1.
Growth hormone 1
–
Somatotropin is a protein that in humans is encoded by the GH1 gene. The protein encoded by this gene is a member of the family of hormones that play an important role in growth control. The five genes share a high degree of sequence identity. Alternative splicing generates additional isoforms of each of the five growth hormones, leading to further diversity and this particular family member is expressed in the pituitary but not in placental tissue as is the case for the other four genes in the growth hormone locus. Mutations in or deletions of the lead to growth hormone deficiency
Growth hormone 1
Growth hormone 1
–
PDB rendering based on 1a22.
Growth hormone 1
Growth hormone 1
2.
Entrez
–
The name Entrez was chosen to reflect the spirit of welcoming the public to search the content available from the NLM. Entrez Global Query is a search and retrieval system that provides access to all databases simultaneously with a single query string. Entrez can efficiently retrieve related sequences, structures, and references, the Entrez system can provide views of gene and protein sequences and chromosome maps. Some textbooks are available online through the Entrez system. The Entrez front page provides, by default, access to the global query, all databases indexed by Entrez can be searched via a single query string, supporting boolean operators and search term tags to limit parts of the search statement to particular fields. This returns a unified results page, that shows the number of hits for the search in each of the databases, Entrez also provides a similar interface for searching each particular database and for refining search results. The Limits feature allows the user to narrow a search a web forms interface, the History feature gives a numbered list of recently performed queries. Results of previous queries can be referred to by number and combined via boolean operators, search results can be saved temporarily in a Clipboard. Users with a MyNCBI account can save queries indefinitely and also choose to have updates with new search results e-mailed for saved queries of most databases and it is widely used in the field of biotechnology as a reference tool for students and professionals alike. Entrez searches the following databases, PubMed, biomedical literature citations and abstracts, including Medline - articles from journals, in addition to using the search engine forms to query the data in Entrez, NCBI provides the Entrez Programming Utilities for more direct access to query results. The eUtils are accessed by posting specially formed URLs to the NCBI server, there was also an eUtils SOAP interface which was terminated on July 2015. In 1991, entrez was introduced in CD form, in 1993, a client-server version of the software provided connectivity with the internet. In 1994, NCBI established a website, and Entrez was a part of initial release. In 2001, Entrez bookshelf was released and in 2003, the Entrez Gene database was developed, Entrez search engine form Entrez Help
Entrez
–
The NCBI Entrez CD-ROM c. 1996
Entrez
–
The Entrez logo
3.
National Center for Biotechnology Information
–
The National Center for Biotechnology Information is part of the United States National Library of Medicine, a branch of the National Institutes of Health. The NCBI is located in Bethesda, Maryland and was founded in 1988 through legislation sponsored by Senator Claude Pepper, the NCBI houses a series of databases relevant to biotechnology and biomedicine and is an important resource for bioinformatics tools and services. Major databases include GenBank for DNA sequences and PubMed, a database for the biomedical literature. Other databases include the NCBI Epigenomics database, all these databases are available online through the Entrez search engine. NCBI is directed by David Lipman, one of the authors of the BLAST sequence alignment program. He also leads a research program, including groups led by Stephen Altschul, David Landsman, Eugene Koonin, John Wilbur, Teresa Przytycka. NCBI is listed in the Registry of Research Data Repositories re3data. org, NCBI has had responsibility for making available the GenBank DNA sequence database since 1992. GenBank coordinates with individual laboratories and other databases such as those of the European Molecular Biology Laboratory. Since 1992, NCBI has grown to other databases in addition to GenBank. The NCBI assigns a unique identifier to each species of organism, the NCBI has software tools that are available by WWW browsing or by FTP. For example, BLAST is a sequence similarity searching program, BLAST can do sequence comparisons against the GenBank DNA database in less than 15 seconds. RAG2/IL2RG The NCBI Bookshelf is a collection of freely accessible, downloadable, some of the books are online versions of previously published books, while others, such as Coffee Break, are written and edited by NCBI staff. BLAST is a used for calculating sequence similarity between biological sequences such as nucleotide sequences of DNA and amino acid sequences of proteins. BLAST is a tool for finding sequences similar to the query sequence within the same organism or in different organisms. It searches the query sequence on NCBI databases and servers and post the results back to the browser in chosen format. Input sequences to the BLAST are mostly in FASTA or Genbank format while output could be delivered in variety of such as HTML, XML formatting. HTML is the output format for NCBIs web-page. Entrez is both indexing and retrieval system having data from sources for biomedical research
National Center for Biotechnology Information
–
National Center for Biotechnology Information logo
4.
Swiss-Prot
–
UniProt is a freely accessible database of protein sequence and functional information, many entries being derived from genome sequencing projects. It contains an amount of information about the biological function of proteins derived from the research literature. The UniProt consortium comprises the European Bioinformatics Institute, the Swiss Institute of Bioinformatics, EBI, located at the Wellcome Trust Genome Campus in Hinxton, UK, hosts a large resource of bioinformatics databases and services. SIB, located in Geneva, Switzerland, maintains the ExPASy servers that are a resource for proteomics tools. In 2002, EBI, SIB, and PIR joined forces as the UniProt consortium, each consortium member is heavily involved in protein database maintenance and annotation. Until recently, EBI and SIB together produced the Swiss-Prot and TrEMBL databases and these databases coexisted with differing protein sequence coverage and annotation priorities. Swiss-Prot aimed to provide reliable protein sequences associated with a level of annotation. Recognizing that sequence data were being generated at a pace exceeding Swiss-Prots ability to keep up, meanwhile, PIR maintained the PIR-PSD and related databases, including iProClass, a database of protein sequences and curated families. The consortium members pooled their resources and expertise, and launched UniProt in December 2003. UniProt provides four core databases, UniProtKB, UniParc, UniRef, UniProt Knowledgebase is a protein database partially curated by experts, consisting of two sections, UniProtKB/Swiss-Prot and UniProtKB/TrEMBL. As of 19 March 2014, release 2014_03 of UniProtKB/Swiss-Prot contains 542,782 sequence entries, UniProtKB/Swiss-Prot is a manually annotated, non-redundant protein sequence database. It combines information extracted from literature and biocurator-evaluated computational analysis. The aim of UniProtKB/Swiss-Prot is to all known relevant information about a particular protein. Annotation is regularly reviewed to keep up with current scientific findings, the manual annotation of an entry involves detailed analysis of the protein sequence and of the scientific literature. Sequences from the gene and the same species are merged into the same database entry. Differences between sequences are identified, and their cause documented, a range of sequence analysis tools is used in the annotation of UniProtKB/Swiss-Prot entries. Computer-predictions are manually evaluated, and relevant results selected for inclusion in the entry and these predictions include post-translational modifications, transmembrane domains and topology, signal peptides, domain identification, and protein family classification. Relevant publications are identified by searching databases such as PubMed, the full text of each paper is read, and information is extracted and added to the entry
Swiss-Prot
–
UniProt
5.
Locus (genetics)
–
A locus in genetics is the position on a chromosome. Each chromosome carries many genes, humans estimated haploid protein coding genes are 19, 000-20,000, a variant of the similar DNA sequence located at a given locus is called an allele. The ordered list of known for a particular genome is called a gene map. Gene mapping is the process of determining the locus for a biological trait. The chromosomal locus of a gene might be written 3p22.1, here 3 means chromosome 3, p means p-arm. And 22 refers to region 2, band 2 and this is read as two two, not as twenty-two. So the entire locus is read as three P two two point one, the cytogenetic bands are counting from the centromere out toward the telomeres. A range of loci is specified in a similar way. For example, the locus of gene OCA1 may be written 11q1. 4-q2.1, meaning it is on the arm of chromosome 11. The ends of a chromosome are labeled pter and qter, a centisome is defined as 1% of a chromosome length. Chromosomal translocation Cytogenetic notation Karyotype Null allele Michael, R. Cummings, belmont, California, Brooks/Cole Overview at ornl. gov Chromosome Banding and Nomenclature from NCBI
Locus (genetics)
–
Chromosome components: (1)
Chromatid (2)
Centromere (3) Short (p) arm (4) Long (q) arm
Locus (genetics)
–
Short and long arms
6.
Chromosome 17 (human)
–
Chromosome 17 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome, chromosome 17 spans more than 83 million base pairs and represents between 2.5 and 3% of the total DNA in cells. Identifying genes on each chromosome is an area of genetic research. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome varies, in January 2017, two estimates differed by 9%, with one estimate giving 2,432 genes, and the other estimate giving 2,653 genes. Chromosome 17 contains the Homeobox B gene cluster, disease genes and chromosomes, disease maps of the human genome
Chromosome 17 (human)
–
Pair of human chromosome 17 (after
G-banding). One is from mother, one is from father.
7.
Growth hormone 2
–
Growth hormone variant is a protein that in humans is encoded by the GH2 gene. The protein encoded by this gene is a member of the family of hormones. The five genes share a high degree of sequence identity. Alternative splicing generates additional isoforms of each of the five growth hormones, leading to further diversity, as in the case of its pituitary counterpart, growth hormone 1, the predominant isoform of this particular family member shows similar somatogenic activity, with reduced lactogenic activity. Mutations in this lead to placental growth hormone/lactogen deficiency
Growth hormone 2
Growth hormone 2
–
PDB rendering based on 1a22.
Growth hormone 2
Growth hormone 2
8.
Cell (biology)
–
The cell is the basic structural, functional, and biological unit of all known living organisms. A cell is the smallest unit of life that can replicate independently, the study of cells is called cell biology. Cells consist of cytoplasm enclosed within a membrane, which contains many such as proteins. Organisms can be classified as unicellular or multicellular, while the number of cells in plants and animals varies from species to species, humans contain more than 10 trillion cells. Most plant and animal cells are only under a microscope. The cell was discovered by Robert Hooke in 1665, who named the unit for its resemblance to cells inhabited by Christian monks in a monastery. Cells emerged on Earth at least 3.5 billion years ago, Cells are of two types, eukaryotic, which contain a nucleus, and prokaryotic, which do not. Prokaryotes are single-celled organisms, while eukaryotes can be either single-celled or multicellular, prokaryotic cells were the first form of life on Earth, characterised by having vital biological processes including cell signaling and being self-sustaining. They are simpler and smaller than eukaryotic cells, and lack membrane-bound organelles such as the nucleus, prokaryotes include two of the domains of life, bacteria and archaea. The DNA of a prokaryotic cell consists of a chromosome that is in direct contact with the cytoplasm. The nuclear region in the cytoplasm is called the nucleoid, most prokaryotes are the smallest of all organisms ranging from 0.5 to 2.0 µm in diameter. Though most prokaryotes have both a cell membrane and a wall, there are exceptions such as Mycoplasma and Thermoplasma which only possess the cell membrane layer. The envelope gives rigidity to the cell and separates the interior of the cell from its environment, the cell wall consists of peptidoglycan in bacteria, and acts as an additional barrier against exterior forces. It also prevents the cell from expanding and bursting from osmotic pressure due to a hypotonic environment, some eukaryotic cells also have a cell wall. Inside the cell is the region that contains the genome, ribosomes. The genetic material is found in the cytoplasm. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular, linear bacterial plasmids have been identified in several species of spirochete bacteria, including members of the genus Borrelia notably Borrelia burgdorferi, which causes Lyme disease. Though not forming a nucleus, the DNA is condensed in a nucleoid, plasmids encode additional genes, such as antibiotic resistance genes
Cell (biology)
–
Onion (
Allium) cells in different phases of the cell cycle
Cell (biology)
–
Structure of an animal cell
Cell (biology)
–
A fluorescent image of an endothelial cell. Nuclei are stained blue,
mitochondria are stained red, and microfilaments are stained green.
Cell (biology)
–
Human cancer cells with nuclei (specifically the DNA) stained blue. The central and rightmost cell are in
interphase, so the entire nuclei are labeled. The cell on the left is going through
mitosis and its DNA has condensed.
9.
Human development (biology)
–
Human development is the process of growing to maturity. In biological terms, this entails growth from a zygote to an adult human being. Fertilization occurs when the sperm enters the ovums membrane. The genetical material of the sperm and egg that combine to form a cell, called a zygote. The germinal stage refers to the time from fertilization, through the development of the early embryo, the germinal stage is over at about 10 days of gestation. The zygote contains a full complement of genetic material and develops into the embryo, briefly, embryonic developments have four stages, the morula stage, the bastula stage, the gastrula stage, and the neurula stage. Prior to implantation, the remains in a protein shell, the zona pellucida. A week after fertilization the embryo still has not grown in size and this induces a decidual reaction, wherein the uterine cells proliferate and surround the embryo thus causing it to become embedded within the uterine tissue. The embryo, meanwhile, proliferates and develops both into embryonic and extra-embryonic tissue, the forming the fetal membranes and the placenta. In humans, the embryo is referred to as a fetus in the stages of prenatal development. The transition from embryo to fetus is arbitrarily defined as occurring 8 weeks after fertilization, in comparison to the embryo, the fetus has more recognizable external features and a set of progressively developing internal organs. A nearly identical process occurs in other species, auxology Child development Developmental biology Embryogenesis Life-history theory
Human development (biology)
–
"Developmental" redirects here. For other uses, see
Development.
10.
Amino acid
–
Amino acids are organic compounds containing amine and carboxyl functional groups, along with a side chain specific to each amino acid. The key elements of an acid are carbon, hydrogen, oxygen. About 500 amino acids are known and can be classified in many ways, in the form of proteins, amino acids comprise the second-largest component of human muscles, cells and other tissues. Outside proteins, amino acids perform critical roles in such as neurotransmitter transport. In biochemistry, amino acids having both the amine and the acid groups attached to the first carbon atom have particular importance. They are known as 2-, alpha-, or α-amino acids and they include the 22 proteinogenic amino acids, which combine into peptide chains to form the building-blocks of a vast array of proteins. These are all L-stereoisomers, although a few D-amino acids occur in bacterial envelopes, as a neuromodulator, twenty of the proteinogenic amino acids are encoded directly by triplet codons in the genetic code and are known as standard amino acids. The other two are selenocysteine, and pyrrolysine, pyrrolysine and selenocysteine are encoded via variant codons, for example, selenocysteine is encoded by stop codon and SECIS element. N-formylmethionine is generally considered as a form of methionine rather than as a separate proteinogenic amino acid, codon–tRNA combinations not found in nature can also be used to expand the genetic code and create novel proteins known as alloproteins incorporating non-proteinogenic amino acids. Many important proteinogenic and non-proteinogenic amino acids also play critical roles within the body. Nine proteinogenic amino acids are called essential for humans because they cannot be created from other compounds by the human body, others may be conditionally essential for certain ages or medical conditions. Essential amino acids may also differ between species, because of their biological significance, amino acids are important in nutrition and are commonly used in nutritional supplements, fertilizers, and food technology. Industrial uses include the production of drugs, biodegradable plastics, the first few amino acids were discovered in the early 19th century. In 1806, French chemists Louis-Nicolas Vauquelin and Pierre Jean Robiquet isolated a compound in asparagus that was subsequently named asparagine, cystine was discovered in 1810, although its monomer, cysteine, remained undiscovered until 1884. Glycine and leucine were discovered in 1820, usage of the term amino acid in the English language is from 1898. Proteins were found to yield amino acids after enzymatic digestion or acid hydrolysis, in the structure shown at the top of the page, R represents a side chain specific to each amino acid. The carbon atom next to the group is called the α–carbon. Amino acids containing an amino group bonded directly to the alpha carbon are referred to as amino acids
Amino acid
–
The structure of an alpha amino acid in its un-ionized form
11.
Polypeptide
–
Peptides are biologically occurring short chains of amino acid monomers linked by peptide bonds. The covalent chemical bonds are formed when the group of one amino acid reacts with the amine group of another. The shortest peptides are dipeptides, consisting of 2 amino acids joined by a peptide bond, followed by tripeptides, tetrapeptides. A polypeptide is a long, continuous, and unbranched peptide chain, hence, peptides fall under the broad chemical classes of biological oligomers and polymers, alongside nucleic acids, oligosaccharides and polysaccharides, etc. Peptides are distinguished from proteins on the basis of size, all peptides except cyclic peptides have an N-terminal and C-terminal residue at the end of the peptide. Ribosomal peptides Ribosomal peptides are synthesized by translation of mRNA and they are often subjected to proteolysis to generate the mature form. These function, typically in higher organisms, as hormones and signaling molecules, some organisms produce peptides as antibiotics, such as microcins. Since they are translated, the amino acid residues involved are restricted to those utilized by the ribosome, however, these peptides frequently have posttranslational modifications such as phosphorylation, hydroxylation, sulfonation, palmitoylation, glycosylation and disulfide formation. In general, they are linear, although lariat structures have been observed, more exotic manipulations do occur, such as racemization of L-amino acids to D-amino acids in platypus venom. Nonribosomal peptides Nonribosomal peptides are assembled by enzymes that are specific to each peptide, the most common non-ribosomal peptide is glutathione, which is a component of the antioxidant defenses of most aerobic organisms. Other nonribosomal peptides are most common in organisms, plants. These complexes are often out in a similar fashion. These peptides are often cyclic and can have highly complex cyclic structures, since the system is closely related to the machinery for building fatty acids and polyketides, hybrid compounds are often found. The presence of oxazoles or thiazoles often indicates that the compound was synthesized in this fashion, Peptones See also Tryptone Peptones are derived from animal milk or meat digested by proteolysis. In addition to containing small peptides, the material includes fats, metals, salts, vitamins. Peptones are used in nutrient media for growing bacteria and fungi, Peptide fragments Peptide fragments refer to fragments of proteins that are used to identify or quantify the source protein. Peptides received prominence in molecular biology for several reasons, the first is that peptides allow the creation of peptide antibodies in animals without the need of purifying the protein of interest. This involves synthesizing antigenic peptides of sections of the protein of interest and these will then be used to make antibodies in a rabbit or mouse against the protein
Polypeptide
–
A tetrapeptide (example
Val -
Gly -
Ser -
Ala) with green marked
amino end (
L-Valine) and blue marked
carboxyl end (
L-Alanine).
12.
IGF-1
–
Insulin-like growth factor 1, also called somatomedin C, is a protein that in humans is encoded by the IGF1 gene. IGF-1 has also referred to as a sulfation factor and its effects were termed nonsuppressible insulin-like activity in the 1970s. IGF-1 is a similar in molecular structure to insulin. It plays an important role in growth and continues to have anabolic effects in adults. A synthetic analog of IGF-1, mecasermin, is used for the treatment of growth failure, IGF-1 consists of 70 amino acids in a single chain with three intramolecular disulfide bridges. IGF-1 has a weight of 7,649 Dalton. IGF-1 is produced primarily by the liver as an endocrine hormone as well as in tissues in a paracrine/autocrine fashion. Approximately 98% of IGF-1 is always bound to one of 6 binding proteins, IGFBP-3, the most abundant protein, accounts for 80% of all IGF binding. IGF-1 binds to IGFBP-3 in a 1,1 molar ratio, the highest rates of IGF-1 production occur during the pubertal growth spurt. The lowest levels occur in infancy and old age, protein intake increases IGF-1 levels in humans, independent of total calorie consumption. IGF-1 is a mediator of the effects of growth hormone. Growth hormone is made in the pituitary gland, is released into the blood stream. In addition to the effects, IGF-1 can also regulate cell growth and development, especially in nerve cells. Its primary action is mediated by binding to its receptor, the insulin-like growth factor 1 receptor. IGF-1 binds to at least two cell surface receptors, the IGF-1 receptor, and the insulin receptor, the IGF-1 receptor seems to be the physiologic receptor – it binds IGF-1 at significantly higher affinity than the IGF-1 that is bound to the insulin receptor. Like the insulin receptor, the IGF-1 receptor is a tyrosine kinase – meaning it signals by causing the addition of a phosphate molecule on particular tyrosines. IGF-1 activates the receptor at approximately 0.1 times the potency of insulin. Part of this signaling may be via IGF1R/Insulin Receptor heterodimers, insulin-like growth factor 1 has been shown to bind and interact with all the IGF-1 binding proteins, of which there are seven, IGFBP1, IGFBP2, IGFBP3, IGFBP4, IGFBP5, IGFBP6, and IGFBP7
IGF-1
IGF-1
–
PDB rendering based on 1bqt.
IGF-1
IGF-1
13.
Recombinant DNA
–
Recombinant DNA is possible because DNA molecules from all organisms share the same chemical structure. They differ only in the sequence within that identical overall structure. Recombinant DNA is the name for a piece of DNA that has been created by the combination of at least two strands. Recombinant DNA molecules are called chimeric DNA, because they can be made of material from two different species, like the mythical chimera. R-DNA technology uses palindromic sequences and leads to the production of sticky, the DNA sequences used in the construction of recombinant DNA molecules can originate from any species. For example, plant DNA may be joined to bacterial DNA, in addition, DNA sequences that do not occur anywhere in nature may be created by the chemical synthesis of DNA, and incorporated into recombinant molecules. Using recombinant DNA technology and synthetic DNA, literally any DNA sequence may be created and introduced into any of a wide range of living organisms. Proteins that can result from the expression of recombinant DNA within living cells are termed recombinant proteins, when recombinant DNA encoding a protein is introduced into a host organism, the recombinant protein is not necessarily produced. Expression of foreign proteins requires the use of specialized expression vectors, molecular cloning is the laboratory process used to create recombinant DNA. It is one of two widely used methods, along with polymerase chain reaction, used to direct the replication of any specific DNA sequence chosen by the experimentalist, there are two fundamental differences between the methods. One is that cloning involves replication of the DNA within a living cell, while PCR replicates DNA in the test tube. The other difference is that cloning involves cutting and pasting DNA sequences, formation of recombinant DNA requires a cloning vector, a DNA molecule that replicates within a living cell. The choice of vector for molecular cloning depends on the choice of host organism, the size of the DNA to be cloned, the DNA segments can be combined by using a variety of methods, such as restriction enzyme/ligase cloning or Gibson assembly. These steps are described in detail in a related article. Following transplantation into the host organism, the foreign DNA contained within the recombinant DNA construct may or may not be expressed and that is, the DNA may simply be replicated without expression, or it may be transcribed and translated and a recombinant protein is produced. Specific changes to the host organism may be made to improve expression of the ectopic gene, in most cases, organisms containing recombinant DNA have apparently normal phenotypes. Significant exceptions exist, and are discussed below, gross phenotypic changes are not the norm, unless the recombinant gene has been chosen and modified so as to generate biological activity in the host organism. In some cases, recombinant DNA can have deleterious effects even if it is not expressed, one mechanism by which this happens is insertional inactivation, in which the rDNA becomes inserted into a host cells gene
Recombinant DNA
–
A group of
GloFish fluorescent fish
Recombinant DNA
–
Construction of recombinant DNA, in which a foreign DNA fragment is inserted into a plasmid vector. In this example, the gene indicated by the white color is inactivated upon insertion of the foreign DNA fragment.
14.
Prescription drug
–
A prescription drug is a pharmaceutical drug that legally requires a medical prescription to be dispensed. In contrast, over-the-counter drugs can be obtained without a prescription, the reason for this difference in substance control is the potential scope of misuse, from drug abuse to practicing medicine without a license and without sufficient education. Different jurisdictions have different definitions of what constitutes a prescription drug, rx is often used as a short form for prescription drug in North America- a contraction of the Latin word recipe meaning take. Prescription drugs are often dispensed together with a monograph that gives detailed information about the drug, the use of prescription drugs has been increasing since the 1960s. In the U. S. 88% of older adults use at least 1 prescription drug, who is able to prescribe the drug. When purchasing a drug under the PBS the maximum price a consumer pays is the patient co-payment contribution and those covered by government entitlements and those covered under the Repatriation Pharmaceutical Benefits Scheme have a reduced co-payment, which is $6.00 in 2014. The table below indicates the changes in co-payments over the years and these co-payments are compulsory and cannot be discounted by pharmacies under any circumstances. Private prescriptions are issued for medicines not covered on the PBS, or being used off-label, the patient pays the pharmacy for medicines privately prescribed. In the United Kingdom the Medicines Act 1968 and Prescription Only Medicines Order 1997 contain regulations that cover the supply of sale, use, prescribing is also covered by this legislation. A patient visits a medical practitioner or dentist authorised to prescribe drugs and certain other medical items, also, suitably qualified and experienced nurses and pharmacists may be independent prescribers. Both can prescribe all POMs but pharmacists are not allowed to prescribe schedule 1 controlled drugs, once issued, a prescription is taken by the patient to a pharmacy, which dispenses the medicine. Most prescriptions in the UK are NHS prescriptions, subject to a standard charge unrelated to what is dispensed, the NHS prescription fee was increased to £8. The pharmacy charges the NHS the actual cost of the medicine, a patient can consolidate prescription charges using a prescription payment certificate, effectively capping costs at £29.10 per quarter or £104.00 per year. Outside the NHS, private prescriptions are issued by private medical practitioners, NHS supply beyond three months worth is not covered, and must be purchased privately. A patient pays the pharmacy the normal price for medicine prescribed outside the NHS, in the United States, the Federal Food, Drug, and Cosmetic Act defines what substances require a prescription in order to be dispensed by a pharmacy. The Controlled Substances Act was enacted into law by the Congress of the United States in 1970, the CSA is the federal U. S. drug law under which the manufacture, importation, possession, use and distribution of certain substances is regulated. The legislation created five schedules with varying qualifications for a substance to be included in each, the safety and effectiveness of prescription drugs in the US is regulated by the federal Prescription Drug Marketing Act of 1987. The Food and Drug Administration is charged with implementing this law, misuse or abuse of prescription drugs can lead to adverse drug events, including those due to dangerous drug interactions
Prescription drug
–
Regulation of therapeutic goods in the United States
15.
NCAA
–
The National Collegiate Athletic Association is a non-profit association which regulates athletes of 1,281 institutions, conferences, organizations, and individuals. It also organizes the programs of many colleges and universities in the United States and Canada. The organization is headquartered in Indianapolis, Indiana, in 2014, the NCAA generated almost a billion dollars in revenue. 80 to 90% of this revenue was due to the Division I Mens Basketball Tournament and this revenue is then distributed back into various organizations and institutions across the United States. In August 1973, the current three-division setup of Division I, Division II, under NCAA rules, Division I and Division II schools can offer scholarships to athletes for playing a sport. Division III schools may not offer any athletic scholarships, generally, larger schools compete in Division I and smaller schools in II and III. Division I football was divided into I-A and I-AA in 1978. Subsequently, the term Division I-AAA was briefly added to delineate Division I schools which do not field a football program at all, in 2006, Divisions I-A and I-AA were respectively renamed the Football Bowl Subdivision and Football Championship Subdivision. Inter-collegiate sports began in the US in 1852 when crews from Harvard University, as other sports emerged, notably football and basketball, many of these same concepts and standards were adopted. Football, in particular, began to emerge as a marquee sport, the IAAUS was officially established on March 31,1906, and took its present name, the NCAA, in 1910. For several years, the NCAA was a group and rules-making body, but in 1921, the first NCAA national championship was conducted. Gradually, more rules committees were formed and more championships were created, a series of crises brought the NCAA to a crossroads after World War II. The Sanity Code – adopted to establish guidelines for recruiting and financial aid – failed to curb abuses, postseason football games were multiplying with little control, and member schools were increasingly concerned about how the new medium of television would affect football attendance. The complexity of problems and the growth in membership and championships demonstrated the need for full-time professional leadership. Walter Byers, previously an executive assistant, was named executive director in 1951. Byers wasted no time placing his stamp on the Association, as college athletics grew, the scope of the nations athletics programs diverged, forcing the NCAA to create a structure that recognized varying levels of emphasis. In 1973, the Associations membership was divided into three legislative and competitive divisions – I, II, and III, five years later in 1978, Division I members voted to create subdivisions I-A and I-AA in football. Until the 1980s, the association did not offer womens athletics, instead, the Association for Intercollegiate Athletics for Women, with nearly 1000 member schools, governed womens collegiate sports in the United States
NCAA
–
The current NCAA headquarters office in
Indianapolis
NCAA
–
National Collegiate Athletic Association
NCAA
–
NCAA National Championship
trophies, rings, and watches won by
UCLA teams
NCAA
–
2006 NCAA championship banners hang from the ceiling of the NCAA Hall of Champions in Indianapolis.
16.
Urine
–
Urine is a liquid by-product of metabolism in the bodies of many animals, including humans. It is expelled from the kidneys and flows through the ureters to the urinary bladder, cellular metabolism generates numerous by-products, many nitrogenous, that require clearance from the bloodstream. These by-products are eventually expelled from the body during urination, the method for excreting water-soluble chemicals from the body. These chemicals can be detected and analyzed by urinalysis, of the many such substances that exist, the three main nitrogenous wastes of the mammalian body are urea, uric acid, and creatinine. Animal urine forms part of the nitrogen cycle, in balanced ecosystems it fertilizes soil and plants, which in turn continue to support the animal population. Some animals use it to mark their territories, human urine and human feces are collectively referred to as human waste, as sewage, they require sewage treatment in places where population density is high. Livestock urine and feces similarly require proper management if the population density is high. Such management is part of ecological sanitation, most animals have excretory systems for elimination of soluble toxic wastes. In humans, soluble wastes are excreted primarily by the system and, to a lesser extent in terms of urea. The urinary system consists of the kidneys, ureters, urinary bladder, the system produces urine by a process of filtration, reabsorption, and tubular secretion. The kidneys extract the soluble wastes from the bloodstream, as well as water, sugars. The resulting urine contains high concentrations of urea and other substances, urine flows from the kidney through the ureter, bladder, and finally the urethra before passing from the body. Research looking at the duration of urination in a range of species found that 9 larger species urinated for 21 ±13 seconds irrespective of body size. Smaller species including rodents and bats cannot produce jets and instead urinate with a series of drops, producing too much or too little urine needs medical attention. Polyuria is a condition of excessive production of urine, oliguria when <400 mL are produced, about 91-96% of urine consists of water. Urine also contains an assortment of inorganic salts and organic compounds, including proteins, hormones, the total solids in urine are on average 59 g per person per day. Organic matter makes up between 65% and 85% of urine dry solids, with volatile solids comprising 75–85% of total solids, urea is the largest constituent of the solids, constituting more than 50% of the total. On an elemental level, human urine contains 6.87 g/L carbon,8.12 g/L nitrogen,8.25 g/L oxygen, the exact proportions vary with individuals and with factors such as diet and health
Urine
–
Sample of human urine
Urine
–
Urea structure
Urine
–
Green urine during long term infusion of the sedative
propofol
Urine
–
A Doctor Examining Urine.
Trophime Bigot.
17.
Use of performance-enhancing drugs in sport
–
The use of banned drugs to enhance performance is considered unethical, and therefore prohibited, by most international sports organizations, including the International Olympic Committee. Furthermore, athletes taking explicit measures to evade detection exacerbates the ethical violation with overt deception, historically speaking, the origins of doping in sports go back to the very creation of sport itself. From ancient usage of substances in chariot racing to more recent controversies in baseball and cycling, the general trend among authorities and sporting organizations over the past several decades has been to strictly regulate the use of drugs in sport. The reasons for the ban are mainly the health risks of performance-enhancing drugs, the equality of opportunity for athletes, anti-doping authorities state that using performance-enhancing drugs goes against the spirit of sport. There are many suggestions as to the origin of the term doping, one is that it is derived from dop, an alcoholic drink used as a stimulant in ceremonial dances in 18th century Southern Africa. By 1889, dope was used in connection with the preparation of a thick viscous preparation of opium for smoking, in 1900, dope was also defined as a preparation of drugs designed to influence the performance of a racehorse. The use of drugs in sports goes back centuries, about all the way back to the invention of the concept of sports. In ancient times, when the fittest of a nation were selected as athletes or combatants, they were fed diets, for instance, Scandinavian mythology says Berserkers could drink a mixture called butotens, to greatly increase their physical power at the risk of insanity. One theory is that the mixture was prepared from the Amanita muscaria mushroom, the ancient Olympics in Greece have been alleged to have been contaminated with forms of doping. In ancient Rome, where chariot racing had become a part of their culture. By April 1877, walking races had stretched to 500 miles, the event proved popular, however, with 20,000 spectators attending each day. The fascination with six-day bicycle races spread across the Atlantic and the appeal brought in the crowds in America as well. And the more spectators paid at the gate, the higher the prizes could be and their exhaustion was countered by soigneurs, helpers akin to seconds in boxing. Among the treatments they supplied was nitroglycerine, a used to stimulate the heart after cardiac attacks. Riders suffered hallucinations from the exhaustion and perhaps the drugs, the American champion Major Taylor refused to continue the New York race, saying, I cannot go on with safety, for there is a man chasing me around the ring with a knife in his hand. Public reaction turned against such trials, whether individual races or in teams of two and it appears from the reports of this singular performance that some of the bicycle riders have actually become temporarily insane during the contest. Days and weeks of recuperation will be needed to put the racers in condition, the father of anabolic steroids in the United States was John Ziegler, a physician for the U. S. weightlifting team in the mid-20th century. Ziegler learned from his Russian days that the Soviet weightlifting teams success was due to their use of performance-enhancing drugs, deciding that U. S. athletes needed chemical assistance to remain competitive, Ziegler worked with the CIBA Pharmaceutical Company to develop an oral anabolic steroid
Use of performance-enhancing drugs in sport
–
Hicks and supporters at the
1904 Summer Olympics.
Use of performance-enhancing drugs in sport
–
Ilona Slupianek in 1981.
Use of performance-enhancing drugs in sport
–
Controversial athlete
Floyd Landis, shown here at the
2006 Tour of California, triggered a public scandal when caught
doping to help his cycling.
18.
Blood test
–
A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a needle, or via fingerprick. Multiple tests for specific blood components are grouped together into one test panel called a blood panel or blood work. Blood tests are used in health care to determine physiological and biochemical states, such as disease, mineral content, pharmaceutical drug effectiveness. Typical clinical blood panels include a basic metabolic panel or a complete blood count, Blood tests are also used in drug tests to detect drug abuse. In some of the United States, a blood test is required before marriage, venipuncture is useful as it is a minimally invasive way to obtain cells and extracellular fluid from the body for analysis. Blood flows throughout the body, acting as a medium which provides oxygen, coincidentally, the state of the bloodstream affects, or is affected by, many medical conditions. For these reasons, blood tests are the most commonly performed medical tests, if only a few drops of blood are needed, a fingerstick is performed instead of drawing blood from a vein. Phlebotomists, laboratory practitioners and nurses are those charged with patient blood extraction, however, in special circumstances, and emergency situations, paramedics and physicians sometimes extract blood. Also, respiratory therapists are trained to extract arterial blood to examine arterial blood gases, a basic metabolic panel measures sodium, potassium, chloride, bicarbonate, blood urea nitrogen, magnesium, creatinine, glucose, and sometimes calcium. Tests focusing on cholesterol levels can determine LDL and HDL cholesterol levels, some tests, such as those that measure glucose or a lipid profile, require fasting eight to twelve hours prior to the drawing of the blood sample. For the majority of tests, blood is obtained from the patients vein. Other specialized tests, such as the blood gas test. While the regular glucose test is taken at a point in time. Blood tests results should always be interpreted using the ranges provided by the laboratory that performed the test, upon completion of a blood test analysis, patients may receive a report with blood test abbreviations. Examples of common blood test abbreviations are shown below, protein electrophoresis Western blot Liver function tests Polymerase chain reaction. DNA profiling is today possible with very small quantities of blood, this is commonly used in forensic science. Northern blot Sexually transmitted diseases Full blood count Hematocrit MCV Mean corpuscular hemoglobin concentration Erythrocyte sedimentation rate Cross-matching, determination of blood type for blood transfusion or transplants Blood cultures are commonly taken if infection is suspected. Positive cultures and resulting sensitivity results are useful in guiding medical treatment
Blood test
–
A
venipuncture performed using a
vacutainer
Blood test
–
Vacutainer blood bottles
Blood test
–
Samples of human blood collected for testing. The
barcodes contain information that is used to identify the individual from whom the sample was taken and the blood test requested.
19.
World Anti-Doping Agency
–
The World Anti-Doping Agency is a foundation initiated by the International Olympic Committee based in Canada to promote, coordinate and monitor the fight against drugs in sports. The aims of the Council of Europe Anti-Doping Convention are also aligned with those of WADA. The World Anti-Doping Agency is a foundation created through an initiative led by the International Olympic Committee. It was set up on November 10,1999 in Lausanne, Switzerland, as a result of what was called the Declaration of Lausanne, to promote, coordinate, since 2002, the organizations headquarters have been located in Montreal, Quebec, Canada. The Lausanne office became the office for Europe. Other regional offices have established in Africa, Asia/Oceania and Latin America. As of 2014, its president is Sir Craig Reedie, initially funded by the International Olympic Committee, WADA now receives half of its budgetary requirements from them, with the other half coming from various national governments. Its governing bodies are composed in equal parts by representatives from the sporting movement. The agencys key activities include research, education, development of anti-doping capacities. The highest decision-making authority in WADA is the 38-member foundation board, the Foundation Board appoints the agencys president. Most day-to-day management is delegated to a 12-member executive committee, membership of which is split equally between the IOC and governments. There also exist several sub-committees with narrower remits, including a Finance and Administration Committee and it delegates work in individual countries to Regional and National Anti-Doping Organizations and mandates that these organisations are compliant with the World Anti-Doping Code. WADA also accredits around 30 laboratories to perform the scientific analysis for doping control. The statutes of WADA and the World Anti-Doping Code mandate the Court of Arbitration for Sports ultimate jurisdiction in deciding doping-related cases, the Code is a document aiming to harmonize anti-doping regulations in all sports and countries. It embodies an annual list of prohibited substances and methods that sportspersons are not allowed to take or use, in 2004, the World Anti-Doping Code was implemented by sports organizations prior to the Olympic Games in Athens, Greece. In November 2007, more than 600 sports organizations unanimously adopted a revised Code at the Third World Conference on Doping in Sport, the updated code came into effect on January 1,2015. The Anti-Doping Convention of the Council of Europe in Strasbourg was opened for signature on December 16,1989 as the first multilateral legal standard in this field and it has been signed by 48 states including the Council of Europe and non-member states Australia, Belarus, Canada and Tunisia. The Convention is open for signature by other non-European states, in this sense the Convention strives for the same general aims as WADA, without being directly linked to it
World Anti-Doping Agency
–
World Anti-Doping Agency
20.
2004 Olympic Games
–
10,625 athletes competed, some 600 more than expected, accompanied by 5,501 team officials from 201 countries. There were 301 medal events in 28 different sports, Athens 2004 marked the first time since the 1996 Summer Olympics that all countries with a National Olympic Committee were in attendance. 2004 marked the return of the games to the city where they began, a new medal obverse was introduced at these Games, replacing the design by Giuseppe Cassioli that had been used since the 1928 Games. This rectified the long lasting mistake of using a depiction of the Roman Colosseum rather than a Greek venue, the new design features the Panathenaic Stadium. The cost of the 2004 Athens Summer Games has been cited as a contributor to the Greek government-debt crisis, some of the venues lie vacant and rotting, while others are in use, the Independent newspaper reports as many as 21 out of 22 are unused. The final medal tally was led by the United States, followed by China, several World and Olympics records were broken during the games. Several concerns were raised over the preparations of the Games and these included excessive budget overruns, infrastructural compromise, the games were deemed generally successful with the rising standard of competition amongst nations across the world. Athens was chosen as the host city during the 106th IOC Session held in Lausanne on 5 September 1997, Athens had lost its bid to organize the 1996 Summer Olympics to Atlanta nearly seven years before on 18 September 1990, during the 96th IOC Session in Tokyo. 1996 coincided with the 100th Anniversary of the first modern Olympics, under the direction of Gianna Angelopoulos-Daskalaki, Athens pursued another bid, this time for the right to host the Summer Olympics in 2004. After leading all voting rounds, Athens easily defeated Rome in the 5th, cape Town, Stockholm, and Buenos Aires, the three other cities that made the IOC shortlist, were eliminated in prior rounds of voting. Six other cities submitted applications, but their bids were dropped by the IOC in 1996 and these cities were Istanbul, Lille, Rio de Janeiro, San Juan, Seville, Saint Petersburg and Cali. The 2004 Summer Olympic Games cost the Government of Greece €8.954 billion to stage, the Athens 2004 Organizing Committee, responsible for the preparation and organisation of the games, concluded its operations as a company in 2005 with a surplus of €130.6 million. ATHOC contributed €123.6 million of the surplus to the Greek State to cover other related expenditures of the Greek State in organizing of the games, as a result, ATHOC reported in its official published accounts a net profit of €7 million. The State’s contribution to the total ATHOC budget was 8% of its expenditure against an originally anticipated 14%, the overall revenue of ATHOC, including income from tickets, sponsors, broadcasting rights, merchandise sales etc. totalled €2,098.4 million. The largest percentage of income came from broadcasting rights. The overall expenditure of ATHOC was €1,967.8 million. e, the large projects required for the upgrade of the country’s infrastructure, including sports infrastructure, roads, airports, hospitals, power grid etc. This cost, however, is not directly attributable to the organisation of the Games. Such infrastructure projects are considered by all standards as fixed asset investments that stay with the hosting country for decades after the Games
2004 Olympic Games
–
The ceremony for the lighting of the flame is arranged as a pagan pageant, with priestesses dancing.
2004 Olympic Games
–
Games of the XXVIII Olympiad
2004 Olympic Games
–
The OAKA Plaza and Arch adjacent to the Olympic Stadium
2004 Olympic Games
–
Faliro Sports Pavilion Arena
21.
Athens, Greece
–
Athens is the capital and largest city of Greece. In modern times, Athens is a cosmopolitan metropolis and central to economic, financial, industrial, maritime. In 2015, Athens was ranked the worlds 29th richest city by purchasing power, Athens is recognised as a global city because of its location and its importance in shipping, finance, commerce, media, entertainment, arts, international trade, culture, education and tourism. It is one of the biggest economic centres in southeastern Europe, with a financial sector. The municipality of Athens had a population of 664,046 within its limits. The urban area of Athens extends beyond its administrative city limits. According to Eurostat in 2011, the Functional urban areas of Athens was the 9th most populous FUA in the European Union, Athens is also the southernmost capital on the European mainland. The city also retains Roman and Byzantine monuments, as well as a number of Ottoman monuments. Athens is home to two UNESCO World Heritage Sites, the Acropolis of Athens and the medieval Daphni Monastery, Athens was the host city of the first modern-day Olympic Games in 1896, and 108 years later it welcomed home the 2004 Summer Olympics. In Ancient Greek, the name of the city was Ἀθῆναι a plural, in earlier Greek, such as Homeric Greek, the name had been current in the singular form though, as Ἀθήνη. It was possibly rendered in the later on, like those of Θῆβαι and Μυκῆναι. During the medieval period the name of the city was rendered once again in the singular as Ἀθήνα, an etiological myth explaining how Athens has acquired its name was well known among ancient Athenians and even became the theme of the sculpture on the West pediment of the Parthenon. The goddess of wisdom, Athena, and the god of the seas, Poseidon had many disagreements, in an attempt to compel the people, Poseidon created a salt water spring by striking the ground with his trident, symbolizing naval power. However, when Athena created the tree, symbolizing peace and prosperity. Different etymologies, now rejected, were proposed during the 19th century. Christian Lobeck proposed as the root of the name the word ἄθος or ἄνθος meaning flower, ludwig von Döderlein proposed the stem of the verb θάω, stem θη- to denote Athens as having fertile soil. In classical literature, the city was referred to as the City of the Violet Crown, first documented in Pindars ἰοστέφανοι Ἀθᾶναι. In medieval texts, variant names include Setines, Satine, and Astines, today the caption η πρωτεύουσα, the capital, has become somewhat common
Athens, Greece
–
From upper left: the
Acropolis, the
Hellenic Parliament, the
Zappeion, the
Acropolis Museum,
Monastiraki Square, Athens view towards the sea
Athens, Greece
–
Athena, patron goddess of Athens;
National Archaeological Museum
Athens, Greece
–
Acropolis of Athens, with
Odeon of Herodes Atticus seen on bottom left
Athens, Greece
–
Statue of
Theseus. Theseus was responsible, according to the myth, for the
synoikismos ("dwelling together")—the political unification of
Attica under Athens.
22.
FDA
–
The Food and Drug Administration is a federal agency of the United States Department of Health and Human Services, one of the United States federal executive departments. As of 2017, 3/4th of the FDA budget is funded by the pharmaceutical companies due to the Prescription drug user fee act and these include regulating lasers, cellular phones, condoms and control of disease on products ranging from certain household pets to sperm donation for assisted reproduction. The FDA is led by the Commissioner of Food and Drugs, appointed by the President with the advice, the Commissioner reports to the Secretary of Health and Human Services. Dr. Robert M. Califf, MD is the current commissioner, who took over in February 2016 for Dr. Stephen Ostroff, the FDA has its headquarters in unincorporated White Oak, Maryland. The agency also has 223 field offices and 13 laboratories located throughout the 50 states, the United States Virgin Islands, in 2008, the FDA began to post employees to foreign countries, including China, India, Costa Rica, Chile, Belgium, and the United Kingdom. The site was renamed from the White Oak Naval Surface Warfare Center to the Federal Research Center at White Oak, the first building, the Life Sciences Laboratory, was dedicated and opened with 104 employees on the campus in December 2003. Only one original building from the facility was kept. All other buildings are new construction, the project is slated to be completed by 2017, assuming future Congressional funding While most of the Centers are located in the Washington, D. C. The Office of Regulatory Affairs is considered the eyes and ears of the agency, the Office of Regulatory Affairs is divided into five regions, which are further divided into 20 districts. Districts are based roughly on the divisions of the federal court system. Each district comprises a main office and a number of Resident Posts. ORA also includes the Agencys network of laboratories, which analyze any physical samples taken. Though samples are usually food-related, some laboratories are equipped to analyze drugs, cosmetics, the Office of Criminal Investigations was established in 1991 to investigate criminal cases. Unlike ORA Investigators, OCI Special Agents are armed, and dont focus on aspects of the regulated industries. In many cases, OCI pursues cases involving Title 18 violations, OCI Special Agents often come from other criminal investigations backgrounds, and work closely with the Federal Bureau of Investigation, Assistant Attorney General, and even Interpol. OCI receives cases from a variety of sources—including ORA, local agencies, OCI is a smaller branch, comprising about 200 agents nationwide. The FDA frequently works with federal agencies, including the Department of Agriculture, Drug Enforcement Administration, Customs and Border Protection. Often local and state government agencies also work with the FDA to provide regulatory inspections, the FDA regulates more than US$1 trillion worth of consumer goods, about 25% of consumer expenditures in the United States
FDA
–
FDA Building 31 houses the Office of the Commissioner and the Office of Regulatory Affairs.
FDA
–
Food and Drug Administration
FDA
–
Regulation of therapeutic goods in the United States
FDA
–
FDA Building 51 houses the Center for Drug Evaluation and Research.
23.
Industrial agriculture
–
Intensive farming or intensive agriculture is any of various types of agriculture that involve higher levels of input and output per unit of agricultural land area. It is characterised by a low ratio, higher use of inputs such as capital and labour. This is in contrast to agriculture in which the inputs per unit land are lower. The term intensive has various senses, some of which refer to organic farming methods and others of which refer to nonorganic, both increase the yields of food and fiber per acre as compared to traditional animal husbandry. In CAFO, feed is brought to the animals, while in MIRG the animals are repeatedly moved to fresh forage. Most commercial agriculture is intensive in one or more ways, forms that rely especially heavily on industrial methods are often called industrial agriculture, which is characterised by innovations designed to increase yield. Techniques include planting multiple crops per year, reducing the frequency of fallow years, intensive farms are widespread in developed nations and increasingly prevalent worldwide. Most of the meat, dairy, eggs, fruits and vegetables available in supermarkets are produced by such farms, smaller intensive farms usually include higher inputs of labor and more often use sustainable intensive methods. The farming practices commonly found on farms are referred to as appropriate technology. These farms are widespread in both developed countries and worldwide, but are growing more rapidly. Most of the food available in specialty markets such as farmers markets is produced by these smallholder farms, agricultural development in Britain between the 16th century and the mid-19th century saw a massive increase in agricultural productivity and net output. This in turn supported unprecedented population growth, freeing up a significant percentage of the workforce, historians cited enclosure, mechanization, four-field crop rotation, and selective breeding as the most important innovations. Industrial agriculture arose along with the Industrial Revolution, by the early 19th century, agricultural techniques, implements, seed stocks and cultivars had so improved that yield per land unit was many times that seen in the Middle Ages. The industrialization phase involved a process of mechanization. Horse-drawn machinery such as the McCormick reaper revolutionized harvesting, while inventions such as the cotton gin reduced the cost of processing, during this same period, farmers began to use steam-powered threshers and tractors, although they were expensive and dangerous. Mechanical harvesters, planters, transplanters and other equipment were then developed and these inventions increased yields and allowed individual farmers to manage increasingly large farms. The identification of nitrogen, potassium, and phosphorus as critical factors in plant growth led to the manufacture of synthetic fertilizers, in 1909 the Haber-Bosch method to synthesize ammonium nitrate was first demonstrated. Farmers adopting this approach were initially referred to as humus farmers, chemicals developed for use in World War II gave rise to synthetic pesticides
Industrial agriculture
–
Agriculture
Industrial agriculture
–
Early 20th century image of a tractor ploughing an
alfalfa field.
Industrial agriculture
–
A commercial chicken house raising broiler pullets for meat.
Industrial agriculture
–
Satellite image of circular crop fields in
Haskell County, Kansas in late June 2001. Healthy, growing crops of
corn and
sorghum are green (Sorghum may be slightly paler).
Wheat is brilliant gold. Fields of brown have been recently harvested and plowed under or have lain in fallow for the year.
24.
Bovine somatotropin
–
Bovine somatotropin or bovine somatotrophin, or bovine growth hormone, is a peptide hormone produced by cows pituitary glands. Like other hormones, it is produced in quantities and is used in regulating metabolic processes. Four large pharmaceutical companies, Monsanto, American Cyanamid, Eli Lilly, Monsanto was the first firm to receive approval. Other countries also approved rBST for commercial use, Monsanto licensed Genentechs patent, and marketed their product as Posilac. In October 2008, Monsanto sold this business, in full, to Eli Lilly, RBST has not been allowed on the market in Canada, Australia, New Zealand, Japan, Israel, or the European Union since 2000. Argentina also banned the use of rBST, the FDA, World Health Organization, and National Institutes of Health have independently stated that dairy products and meat from BST-treated cows are safe for human consumption. In the United States, public opinion led some manufacturers and retailers to market only milk that is rBST-free, in 1937, the administration of BST was shown to increase the milk yield in lactating cows by preventing mammary cell death in dairy cattle. Until the 1980s, use of the compound was very limited in agriculture as the source of the hormone was from bovine carcasses. During this time, the knowledge of the structure and function of the hormone increased, with the advent of biotechnology, one of the pioneering biotech companies, Genentech, succeeded in cloning the gene for BST. The two companies used genetic engineering to clone the BST gene into E. coli, the bacteria are grown in bioreactors, then broken up and separated from the rBST, which is purified to produce the injectable hormone. They published their first field trial results in 1981, Lilly, American Cyanamid, Upjohn, and Monsanto all submitted applications to market rBST to the U. S. Patrick Leahy. FDA approved Monsantos application in 1993, Monsanto launched rBST, brand-named Posilac, in 1994. An average dairy cow begins her lactation with a daily level of milk production. This daily output increases until, at about 70 days into the lactation, production peaks, from that time until the cow is dry, production slowly decreases. This increase and decrease in production is partially caused by the count of milk-producing cells in the udder, cell counts begin at a moderate number, increase during the first part of the lactation, then decrease as the lactation proceeds. Once lost, these generally do not regrow until the next lactation. The effects are mediated by the growth factor system, which is upregulated in response to BST or rBST administration in well-fed cows. From 2000-2005, the USDA National Agricultural Statistics Service survey of dairy producers found that about 17% of producers used rBST, the 2010 USDA National Agricultural Statistics Service survey of Wisconsin farms found that about 18% of dairy farms used rBST
Bovine somatotropin
–
rBST is a product primarily given to
dairy cattle by injection to increase milk production.
Bovine somatotropin
–
The use of rBST increases health problems with cows, including
mastitis.
25.
Somatomammotropin
–
Human placental lactogen, also called human chorionic somatomammotropin, is a polypeptide placental hormone, the human form of placental lactogen. Its structure and function are similar to those of growth hormone. It modifies the state of the mother during pregnancy to facilitate the energy supply of the fetus. HPL is a hormone secreted by the syncytiotrophoblast during pregnancy, like human growth hormone, hPL is encoded by genes on chromosome 17q22-24. HPL molecular mass is 22,125 and contains single chain consisting of 191 amino acid residues that are linked by two disulfide bonds and the structure contains 8 helices, maximum levels are reached near term, typically to 5–7 mg/L. Higher levels are noted in patients with multiple gestation, little hPL enters the fetal circulation. Its biological half-life is 15 minutes, HPL affects the metabolic system of the maternal organism in the following manners, In a bioassay hPL mimics the action of prolactin, yet it is unclear whether hPL has any role in human lactation. Metabolic ↓ maternal insulin sensitivity leading to an increase in blood glucose levels. ↓ maternal glucose utilization, which ensure adequate fetal nutrition. Chronic hypoglycemia leads to a rise in hPL. ↑ lipolysis with the release of fatty acids. With fasting and release of hPL, free fatty acids become available for the organism as fuel. Also, ketones formed from fatty acids can cross the placenta. These functions help support fetal nutrition even in the case of maternal malnutrition, an enhancer for the human placental lactogen gene is found 2 kb downstream of the gene and participates in the cell-specific control gene expression. While hPL has been used as an indicator of fetal well-being and growth, also, normal pregnancies have been reported with undetectable maternal levels of hPL. Placental lactogen in other species Somatotropin family RCSB Protein Data Bank - Structure Summary for 1Z7C - Crystal Structure of Human Placental Lactogen, Human Chorionic Somatomammotropin Enhancer Function Is Mediated by Cooperative Binding of TEF-1 and CSEF-1 to Multiple, Low-Affinity Binding Sites. Speroff L, Glass RH, Kase NG, hagerstwon, MD, Lippincott Williams & Wilkins. Human Placental Lactogen at the US National Library of Medicine Medical Subject Headings
Somatomammotropin
–
Crystal Structure of Human Placental Lactogen.
26.
Prolactin
–
Prolactin, also known as luteotropic hormone or luteotropin, is a protein that is best known for its role in enabling mammals, usually females, to produce milk. It is influential in over 300 separate processes in various vertebrates, Prolactin is secreted from the pituitary gland in response to eating, mating, estrogen treatment, ovulation and nursing. Prolactin is secreted in pulses in between these events, Prolactin plays an essential role in metabolism, regulation of the immune system and pancreatic development. Discovered in non-human animals around 1930 by Oscar Riddle and confirmed in humans in 1970 by Henry Friesen prolactin is a peptide hormone and it is associated with human milk production. In fish it is thought to be related to control of water, Prolactin also acts in a cytokine-like manner and as an important regulator of the immune system. It has important cell cycle-related functions as a growth-, differentiating-, as a growth factor, binding to cytokine-like receptors, it influences hematopoiesis, angiogenesis and is involved in the regulation of blood clotting through several pathways. The hormone acts in endocrine, autocrine and paracrine manner through the prolactin receptor, pituitary prolactin secretion is regulated by endocrine neurons in the hypothalamus. Thyrotropin-releasing factor has an effect on prolactin release, however prolactin is the only adenohypophyseal hormone whose principal control is inhibitory. Several variants and forms are known per species, many fish have variants prolactin A and prolactin B. Most vertebrates including humans also have the closely related somatolactin, in humans, three smaller and several larger variants exist. Prolactin has a variety of effects. Sometimes, newborns secrete a substance from their nipples known as witchs milk. This is in part caused by maternal prolactin and other hormones, Prolactin plays an important role in maternal behavior. Prolactin provides the body with sexual gratification after sexual acts, The hormone counteracts the effect of dopamine and this is thought to cause the sexual refractory period. The amount of prolactin can be an indicator for the amount of satisfaction and relaxation. Unusually high amounts are suspected to be responsible for impotence and loss of libido, elevated levels of prolactin decrease the levels of sex hormones — estrogen in women and testosterone in men. The effects of elevated levels of prolactin are much more variable, in women. Prolactin is sometimes classified as a gonadotropin although in humans it has only a weak luteotropic effect while the effect of suppressing classical gonadotropic hormones is more important, Prolactin within the normal reference ranges can act as a weak gonadotropin, but at the same time suppresses GnRH secretion
Prolactin
–
PDB rendering based on 1n9d.
27.
Atomic mass unit
–
The unified atomic mass unit or dalton is a standard unit of mass that quantifies mass on an atomic or molecular scale. One unified atomic mass unit is approximately the mass of one nucleon and is equivalent to 1 g/mol. The CIPM has categorised it as a non-SI unit accepted for use with the SI, the amu without the unified prefix is technically an obsolete unit based on oxygen, which was replaced in 1961. However, many still use the term amu but now define it in the same way as u. In this sense, most uses of the atomic mass units. For standardization a specific atomic nucleus had to be chosen because the mass of a nucleon depends on the count of the nucleons in the atomic nucleus due to mass defect. This is also why the mass of a proton or neutron by itself is more than 1 u, the atomic mass unit is not the unit of mass in the atomic units system, which is rather the electron rest mass. The relative atomic mass scale has traditionally been a relative value and this evaluation was made prior to the discovery of the existence of elemental isotopes, which occurred in 1912. The divergence of these values could result in errors in computations, the chemistry amu, based on the relative atomic mass of natural oxygen, was about 1.000282 as massive as the physics amu, based on pure isotopic 16O. For these and other reasons, the standard for both physics and chemistry was changed to carbon-12 in 1961. The choice of carbon-12 was made to minimise further divergence with prior literature. The new and current unit was referred to as the atomic mass unit u. and given a new symbol, u. The Dalton is another name for the atomic mass unit. 1 u = m u =112 m Despite this change, modern sources often use the old term amu but define it as u. Therefore, in general, amu likely does not refer to the old oxygen standard unit, the unified atomic mass unit and the dalton are different names for the same unit of measure. As with other names such as watt and newton, dalton is not capitalized in English. In 2003 the Consultative Committee for Units, part of the CIPM, recommended a preference for the usage of the dalton over the atomic mass unit as it is shorter. In 2005, the International Union of Pure and Applied Physics endorsed the use of the dalton as an alternative to the atomic mass unit
Atomic mass unit
–
Base units
28.
Species
–
In biology, a species is the basic unit of biological classification and a taxonomic rank. A species is defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction. While this definition is often adequate, looked at more closely it is problematic, for example, with hybridisation, in a species complex of hundreds of similar microspecies, or in a ring species, the boundaries between closely related species become unclear. Other ways of defining species include similarity of DNA, morphology, all species are given a two-part name, a binomial. The first part of a binomial is the genus to which the species belongs, the second part is called the specific name or the specific epithet. For example, Boa constrictor is one of four species of the Boa genus, Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped that species could evolve given sufficient time, Charles Darwins 1859 book The Origin of Species explained how species could arise by natural selection. Genes can sometimes be exchanged between species by horizontal transfer, and species may become extinct for a variety of reasons. In his biology, Aristotle used the term γένος to mean a kind, such as a bird or fish, a kind was distinguished by its attributes, for instance, a bird has feathers, a beak, wings, a hard-shelled egg, and warm blood. A form was distinguished by being shared by all its members, Aristotle believed all kinds and forms to be distinct and unchanging. His approach remained influential until the Renaissance, when observers in the Early Modern period began to develop systems of organization for living things, they placed each kind of animal or plant into a context. Many of these early delineation schemes would now be considered whimsical, animals likewise that differ specifically preserve their distinct species permanently, one species never springs from the seed of another nor vice versa. In the 18th century, the Swedish scientist Carl Linnaeus classified organisms according to shared physical characteristics and he established the idea of a taxonomic hierarchy of classification based upon observable characteristics and intended to reflect natural relationships. At the time, however, it was widely believed that there was no organic connection between species, no matter how similar they appeared. However, whether or not it was supposed to be fixed, by the 19th century, naturalists understood that species could change form over time, and that the history of the planet provided enough time for major changes. Jean-Baptiste Lamarck, in his 1809 Zoological Philosophy, described the transmutation of species, proposing that a species could change over time, in 1859, Charles Darwin and Alfred Russel Wallace provided a compelling account of evolution and the formation of new species. Darwin argued that it was populations that evolved, not individuals and this required a new definition of species. Darwin concluded that species are what appear to be, ideas
Species
–
John Ray
Species
–
Carl Linnaeus believed in the fixity of species.
29.
Old World monkey
–
The Old World monkeys or Cercopithecidae are a family of catarrhines, the only family in the superfamily Cercopithecoidea in the clade of Catarrhini. However, a group of monkeys still survives in Gibraltar to this day. Old World monkeys include many of the most familiar species of primates, such as baboons. Old World monkeys are medium to large in size, and range from arboreal forms, such as the monkeys, to fully terrestrial forms. By superficial appearance, Old World monkeys are unlike apes in that most have tails and, unlike the New World monkeys, technically, the distinction of catarrhines from platyrrhines depends on the structure of the nose, and the distinction of Old World monkeys from apes depends on dentition. In platyrrhines, the nostrils face sideways, while in catarrhines, for example, the colobus monkeys have stubs for thumbs to assist with their arboreal movement, the proboscis monkey has an extraordinary nose, while the snub-nosed monkeys have almost no nose at all. The male mandrills penis is red and the scrotum is lilac, the coloration is more pronounced in dominant males. Most Old World monkeys are at least partially omnivorous, but all prefer plant matter, the Barbary macaques diet consists mostly of leaves and roots, though it will also eat insects and uses cedar trees as a water source. Gestation in the Old World monkeys lasts between five and seven months, births are usually single, although, as with humans, twins occur from time to time. The young are born relatively well-developed, and are able to cling onto their mothers fur with their hands from birth, compared with most other mammals, they take a long time to reach sexual maturity, with four to six years being typical of most species. In most species, daughters remain with their mothers for life, males leave the group on reaching adolescence, and find a new troop to join. In many species, only an adult male lives with each group, driving off all rivals. Group sizes are variable, even within species, depending on the availability of food. Therefore, cladistically, apes, catarrhines and related contemporary extinct groups such as Parapithecidaea are monkeys as well, for any consistent definition of monkey
Old World monkey
Old World monkey
–
Paracolobus chemeroni fossil
Old World monkey
–
Black-footed gray langur, Semnopithecus hypoleucos
30.
Growth hormone receptor
–
Growth hormone receptor is a protein that in humans is encoded by the GHR gene. GHR orthologs have been identified in most mammals and this gene encodes a protein that is a transmembrane receptor for growth hormone. Binding of growth hormone to the leads to receptor dimerization. A common alternate allele of this gene, called GHRd3, lacks exon three and has been well-characterized, mutations in this gene have been associated with Laron syndrome, also known as the growth hormone insensitivity syndrome, a disorder characterized by short stature. Other splice variants, including one encoding a soluble form of the protein, have observed but have not been thoroughly characterized. Laron mice, have a reduction in body mass. Growth hormone receptor has shown to interact with SGTA, PTPN11, Janus kinase 2, Suppressor of cytokine signaling 1. The GHR gene is used in animals as a nuclear DNA phylogenetic marker, the exon 10 has first been experienced to explore the phylogeny of the major groups of Rodentia. GHR has also proven useful at lower levels, e. g. in octodontoid, arvicoline, muroid, murine, and peromyscine rodents, in arctoid and felid carnivores. Note that the GHR intron 9 has also used to investigate the mustelid and hyaenid carnivores phylogenetics. Growth hormone receptor antagonists such as pegvisomant are used in the treatment of acromegaly and they are used if the tumor of the pituitary gland causing the acromegaly cannot be controlled with surgery or radiation, and the use of somatostatin analogues is unsuccessful. Pegvisomant is delivered as a powder that is mixed with water and injected under the skin
Growth hormone receptor
Growth hormone receptor
–
PDB rendering based on 1a22.
Growth hormone receptor
Growth hormone receptor
31.
Molecule
–
A molecule is an electrically neutral group of two or more atoms held together by chemical bonds. Molecules are distinguished from ions by their lack of electrical charge, however, in quantum physics, organic chemistry, and biochemistry, the term molecule is often used less strictly, also being applied to polyatomic ions. In the kinetic theory of gases, the molecule is often used for any gaseous particle regardless of its composition. According to this definition, noble gas atoms are considered molecules as they are in fact monoatomic molecules. A molecule may be homonuclear, that is, it consists of atoms of one element, as with oxygen, or it may be heteronuclear. Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are not considered single molecules. Molecules as components of matter are common in organic substances and they also make up most of the oceans and atmosphere. Also, no typical molecule can be defined for ionic crystals and covalent crystals, the theme of repeated unit-cellular-structure also holds for most condensed phases with metallic bonding, which means that solid metals are also not made of molecules. In glasses, atoms may also be together by chemical bonds with no presence of any definable molecule. The science of molecules is called molecular chemistry or molecular physics, in practice, however, this distinction is vague. In molecular sciences, a molecule consists of a system composed of two or more atoms. Polyatomic ions may sometimes be thought of as electrically charged molecules. The term unstable molecule is used for very reactive species, i. e, according to Merriam-Webster and the Online Etymology Dictionary, the word molecule derives from the Latin moles or small unit of mass. Molecule – extremely minute particle, from French molécule, from New Latin molecula, diminutive of Latin moles mass, a vague meaning at first, the vogue for the word can be traced to the philosophy of Descartes. The definition of the molecule has evolved as knowledge of the structure of molecules has increased, earlier definitions were less precise, defining molecules as the smallest particles of pure chemical substances that still retain their composition and chemical properties. Molecules are held together by covalent bonding or ionic bonding. Several types of non-metal elements exist only as molecules in the environment, for example, hydrogen only exists as hydrogen molecule. A molecule of a compound is made out of two or more elements, a covalent bond is a chemical bond that involves the sharing of electron pairs between atoms
Molecule
–
Atomic force microscopy image of a
PTCDA molecule, which contains five carbon rings in a non-linear arrangement.
Molecule
Molecule
–
A
scanning tunneling microscopy image of
pentacene molecules, which consist of linear chains of five carbon rings.
Molecule
–
Arrangement of
polyvinylidene fluoride molecules in a
nanofiber –
transmission electron microscopy image.
32.
Somatostatin
–
Somatostatin inhibits insulin and glucagon secretion. Among the vertebrates, there exist six different somatostatin genes that have been named SS1, SS2, SS3, SS4, SS5, the six different genes along with the five different somatostatin receptors allows somatostatin to possess a large range of functions. Humans have only one gene, SST. In addition, somatostatin release from cells can act in a paracrine manner. In the stomach, somatostatin acts directly on the parietal cells via a G-protein coupled receptor to reduce acid secretion. Somatostatin is produced by neurons of the ventromedial nucleus of the hypothalamus. These neurons project to the eminence, where somatostatin is released from neurosecretory nerve endings into the hypothalamo-hypophysial system through neuron axons. Somatostatin is then carried to the pituitary gland, where it inhibits the secretion of growth hormone from somatotrope cells. Somatostatin is also produced by other populations that project centrally, i. e. to other areas of the brain. In particular, there are populations of neurons in the arcuate nucleus, the hippocampus. Somatostatin is classified as a hormone, and is induced by low pH. Its actions are spread to different parts of the body, in the anterior pituitary gland, the effects of somatostatin are, Inhibit the release of growth hormone Inhibit the release of thyroid-stimulating hormone Inhibit adenylyl cyclase in parietal cells. Inhibits the release of glucagon Suppresses the exocrine secretory action of pancreas, since it is absorbed poorly from the gut, it is administered parenterally. It is indicated for treatment of carcinoid syndrome and acromegaly. It is also finding increased use in diseases of the liver. Lanreotide is a used in the management of acromegaly and symptoms caused by neuroendocrine tumors. It is a analog of somatostatin, like octreotide. It is available in countries, including the United Kingdom, Australia, and Canada
Somatostatin
–
Sst is expressed in interneurons in the telencephalon of the embryonic day 15.5 mouse.
Allen Brain Atlases
Somatostatin
–
Somatostatin
Somatostatin
–
Sst expression in the adult mouse.
Allen Brain Atlases
33.
Hypophyseal portal system
–
The hypophyseal portal system is a system of blood vessels in the brain that connects the hypothalamus with the anterior pituitary. Its main function is the transport and exchange of hormones to allow a fast communication between both glands, peptides released near the median eminence from hypothalamic nuclei are transported to the anterior pituitary, where they apply their effects. Branches from the carotid artery provide the blood supply to the pituitary. The superior hypophyseal arteries form the primary capillary plexus that supplies blood to the median eminence, from this capillary system, the blood is drained in hypophyseal portal veins into the secondary plexus. The peptides released at the median eminence enter the primary plexus capillaries, from there, they are transported to the anterior pituitary via hypophyseal portal veins to the secondary plexus. The secondary plexus is a network of fenestrated sinusoid capillaries that provide blood to the anterior pituitary, the blood supply and direction of flow in the hypophyseal portal system has been studied over several years on laboratory animals and human cadaver specimens with injection methods. Small ascending vessels arising from the anastomoses that connect the upper with the lower hypophyseal arterial system also supply blood to hypophyseal vessels, the majority of these branches penetrate into the neural tissue to break up into capillaries for rapid hormone exchange. Proper hormone secretion in the fetus is crucial for its growth in the womb of the mother. Hormone-exchanging blood vessels between the hypothalamus and the gland, similar to those of the hypophyseal portal system. In some of the fetuses, portal capillary loops had penetrated into the median eminence and these experimental results give evidence for an early development of what is later the fully developed hypophysial portal system. This can have effects on the respective target glands, making it impossible for them to carry out their functions properly. Occlusions and other issues in the vessels of the hypophysial portal system can also cause complications in the exchange of hormones between the hypothalamus and the pituitary gland. Hypopituitarism Functional Anatomy of the Hypothalamus and Pituitary Gland, Colorado State University
Hypophyseal portal system
–
Hypophyseal portal system
34.
NREM sleep
–
Non-rapid eye movement sleep, or NREM, is, collectively, sleep stages 1–3, previously known as stages 1–4. Rapid eye movement sleep is not included, there are distinct electroencephalographic and other characteristics seen in each stage. Unlike REM sleep, there is little or no eye movement during these stages. Dreaming is rare during NREM sleep, and muscles are not paralyzed as in REM sleep, people who do not go through the sleeping stages properly get stuck in NREM sleep, and because muscles are not paralyzed a person may be able to sleepwalk. According to studies, the activity that takes place during NREM sleep is believed to be thought-like, whereas REM sleep includes hallucinatory. The mental activity that occurs in NREM and REM sleep is a result of two different generators, which explains the difference in mental activity. In addition, there is a parasympathetic dominance during NREM, during the period of Non-REM sleep, the mindset of a person is more organized. The differences in the REM and NREM activity reported is believed to arise from differences in the stages that happen during the two methods of sleep. NREM sleep was divided into four stages in the Rechtschaffen and Kales standardization of 1968 and that has been reduced to three in the 2007 update by The American Academy of Sleep Medicine. Stage 1 – occurs mostly in the beginning of sleep, with eye movement. This state is referred to as relaxed wakefulness. Alpha waves disappear and the wave appears. People aroused from this stage often believe that they have been fully awake, during the transition into stage-1 sleep, it is common to experience hypnic jerks. Stage 2 – no eye movement occurs, and dreaming is very rare, the sleeper is quite easily awakened. EEG recordings tend to show characteristic sleep spindles, which are bursts of high frequency brain activity. Stage 3 – previously divided into stages 3 and 4, is deep sleep, Stage 3 was formerly the transition between stage 2 and stage 4 where delta waves, associated with deep sleep, began to occur, while delta waves dominated in stage 4. In 2007, these were combined into just stage 3 for all of deep sleep, Dreaming is more common in this stage than in other stages of NREM sleep though not as common as in REM sleep. The content of SWS dreams tends to be disconnected, less vivid and this is also the stage during which parasomnias most commonly occur
NREM sleep
–
Stage 1:
35.
Growth hormone releasing hormone receptor
–
The growth-hormone-releasing hormone receptor is a G-protein-coupled receptor that binds growth hormone-releasing hormone. The GHRHR activates a Gs protein that causes a cascade of cAMP via Adenylate cyclase and this gene, expressed in the pituitary, encodes a receptor for growth-hormone-releasing hormone. Binding of this hormone to the leads to synthesis and release of growth hormone. Mutations in this gene have been associated with isolated growth-hormone deficiency, also known as Dwarfism of Sindh, many alternate transcriptional splice variants encoding different isoforms have been described, but only two have been characterized to date
Growth hormone releasing hormone receptor
–
Growth hormone releasing hormone receptor
36.
Ghrelin
–
Besides regulating appetite, ghrelin also plays a significant role in regulating the distribution and rate of use of energy. When the stomach is empty, ghrelin is secreted, Ghrelin is encoded by the GHRL gene and is presumably produced from the cleavage of the prepropeptide ghrelin/obestatin. Full-length preproghrelin is homologous to promotilin and both are members of the motilin family, unlike the case of many other endogenous peptides, ghrelin is able to cross the blood-brain-barrier, giving exogenously-administered ghrelin unique clinical potential. Ghrelin was discovered after the ghrelin receptor was discovered in 1996 and was reported in 1999, the hormone name is based on its role as a growth hormone-releasing peptide, with reference to the Proto-Indo-European root ghre-, meaning to grow. The GHRL gene produces mRNA which has four exons, five products arise, the first is the 117-amino acid preproghrelin. It is cleaved to produce proghrelin which is cleaved to produce a 28-amino acid ghrelin and C-ghrelin, obestatin is presumed to be cleaved from C-ghrelin. Ghrelin only becomes active when caprylic acid is linked posttranslationally to serine at the 3-position by the enzyme ghrelin O-acyltransferase and it is located on the cell membrane of ghrelin cells in the stomach and pancreas. The non-octanoylated form is desacyl ghrelin, in particular, decanoyl ghrelin has been found to constitute a significant portion of circulating ghrelin in mice, but as of 2011 its presence in humans has not been established. The ghrelin cell is known as an A-like cell, X-cell, X/A-like cell, Epsilon cell, P/D sub 1 cell. Ghrelin cells are mainly in the stomach and duodenum, but also in the jejunum, lungs, pancreatic islets, gonads, adrenal cortex, placenta. It has recently shown that ghrelin is produced locally in the brain Ghrelin cells are found in oxyntic glands, pyloric glands. They are ovoid cells with granules, Ghrelin cells are not terminally differentiated in the pancreas, they are progenitor cells that can give rise to A-cells, PP cells and Beta-cells there. The net result of processes is reflected in body weight. At any given moment in time, it may be in equilibrium or disequilibrium, Ghrelin and synthetic ghrelin mimetics increase body weight and fat mass by triggering receptors in the arcuate nucleus that include the orexigenic neuropeptide Y and agouti-related protein neurons. Ghrelin-responsiveness of these neurons is both leptin- and insulin-sensitive, Ghrelin reduces the mechanosensitivity of gastric vagal afferents, so they are less sensitive to gastric distension. Ghrelin receptors are located on neurons in this circuit, hypothalamic ghrelin signalling is required for reward from alcohol and palatable/rewarding foods. Ghrelin also improves endothelial function and inhibits proatherogenic changes in cell cultures and it activates the endothelial isoform of nitric oxide synthase in a pathway that depends on various kinases including Akt. Ghrelin has been linked to inducing appetite and feeding behaviors, circulating ghrelin levels are the highest right before a meal and the lowest right after
Ghrelin
–
Preproghrelin (green and blue) and ghrelin (green).
37.
Growth hormone secretagogue receptor
–
Growth hormone secretagogue receptor, or ghrelin receptor, is a G protein-coupled receptor that binds ghrelin and plays a role in energy homeostasis and regulation of body weight. In the brain, they are located in the ventromedial nucleus and arcuate nucleus. Inverse agonists for the receptor could be particularly interesting for the treatment of obesity. This activity seems to provide a tonic signal required for the development of normal height, two identified transcript variants are expressed in several tissues and are evolutionary conserved in fish and swine. One transcript, 1a, excises an intron and encodes the functional protein, the second transcript retains the intron and does not function as a receptor for ghrelin, however, it may function to attenuate activity of isoform 1a. A range of ligands for the GHSR receptor are now available and are being developed for several clinical applications. On the other hand, GHSR antagonists have anorectic effects and are likely to be useful for the treatment of obesity. A-778,193 Portelli J, Thielemans L, Ver Donck L, Loyens E, Coppens J, Aourz N, Aerssens J, Vermoesen K, Clinckers R, Schallier A, Michotte Y, Moechars D, Collingridge GL, Bortolotto ZA, Smolders I. Inactivation of the constitutively active ghrelin receptor attenuates limbic seizure activity in rodents, IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology
Growth hormone secretagogue receptor
–
Growth hormone secretagogue receptor
38.
Androgen
–
This includes the activity of the primary male sex organs and development of male secondary sex characteristics. Androgens were first discovered in 1936, androgens increase in both boys and girls during puberty. Androgens are also the original anabolic steroids and the precursor of all estrogens, the primary and most well-known androgen is testosterone. Dihydrotestosterone and androstenedione are less known generally, but are of importance in male development. DHT in the embryo life causes differentiation of penis, scrotum, later in life DHT contributes to balding, prostate growth and sebaceous gland activity. Although androgens are described as sex hormones, both males and females have them to varying degrees, as is also true of estrogens. They are one of three types of sex hormones, the others being estrogens like estradiol and progestogens like progesterone, the main subset of androgens, known as adrenal androgens, is composed of 19-carbon steroids synthesized in the zona reticularis, the innermost layer of the adrenal cortex. Adrenal androgens function as weak steroids, and the subset includes dehydroepiandrosterone, dehydroepiandrosterone sulfate, androstenedione, besides testosterone, other androgens include, Dehydroepiandrosterone is a steroid hormone produced in the adrenal cortex from cholesterol. It is the precursor of natural estrogens. DHEA is also called dehydroisoandrosterone or dehydroandrosterone, androstenedione is an androgenic steroid produced by the testes, adrenal cortex, and ovaries. While androstenediones are converted metabolically to testosterone and other androgens, they are also the parent structure of estrone, use of androstenedione as an athletic or bodybuilding supplement has been banned by the International Olympic Committee, as well as other sporting organizations. Androstenediol is the steroid metabolite thought to act as the regulator of gonadotropin secretion. It is found in equal amounts in the plasma and urine of both males and females. Dihydrotestosterone is a metabolite of testosterone, and a potent androgen than testosterone in that it binds more strongly to androgen receptors. It is produced in the skin and reproductive tissue, during mammalian development, the gonads are at first capable of becoming either ovaries or testes. In humans, starting at about week 4, the rudiments are present within the intermediate mesoderm adjacent to the developing kidneys. At about week 6, epithelial sex cords develop within the forming testes, in males, certain Y chromosome genes, particularly SRY, control development of the male phenotype, including conversion of the early bipotential gonad into testes. In males, the sex cords fully invade the developing gonads, the mesoderm-derived epithelial cells of the sex cords in developing testes become the Sertoli cells, which will function to support sperm cell formation
Androgen
–
Effects of anaerobic exercise also vary with length of time.
39.
Estrogen
–
Estrogen or oestrogen is the primary female sex hormone as well as a medication. It is responsible for the development and regulation of the reproductive system. Estrogen may also refer to any substance, natural or synthetic, the estrane steroid estradiol is the most potent and prevalent endogenous estrogen, although several metabolites of estradiol also have estrogenic hormonal activity. They are one of three types of sex hormones, the others being androgens/anabolic steroids like testosterone and progestogens like progesterone, estrogens are synthesized in all vertebrates as well as some insects. Their presence in both vertebrates and insects suggests that sex hormones have an ancient evolutionary history. The three major naturally occurring forms of estrogen in women are estrone, estradiol, and estriol, another type of estrogen called estetrol is produced only during pregnancy. Quantitatively, estrogens circulate at lower levels than androgens in both men and women, while estrogen levels are significantly lower in males compared to females, estrogens nevertheless also have important physiological roles in males. Like all steroid hormones, estrogens readily diffuse across the cell membrane, once inside the cell, they bind to and activate estrogen receptors which in turn modulate the expression of many genes. Additionally, estrogens bind to and activate rapid-signaling membrane estrogen receptors, the three major naturally occurring estrogens in women are estrone, estradiol, and estriol. Estradiol is the predominant estrogen during reproductive years both in terms of serum levels as well as in terms of estrogenic activity. During menopause, estrone is the predominant circulating estrogen and during pregnancy estriol is the predominant circulating estrogen in terms of serum levels. Though estriol is the most plentiful of the three estrogens it is also the weakest, whereas estradiol is the strongest with a potency of approximately 80 times that of estriol. Thus, estradiol is the most important estrogen in non-pregnant females who are between the menarche and menopause stages of life, however, during pregnancy this role shifts to estriol, and in postmenopausal women estrone becomes the primary form of estrogen in the body. Another type of estrogen called estetrol is produced only during pregnancy, all of the different forms of estrogen are synthesized from androgens, specifically testosterone and androstenedione, by the enzyme aromatase. Estradiol, estrone, and estriol have all been approved as drugs and are used medically. Estetrol is currently under development for medical indications, but has not yet approved in any country. A variety of synthetic estrogen esters, such as estradiol valerate, estradiol cypionate, estradiol acetate, estradiol undecylate, polyestradiol phosphate, the aforementioned compounds behave as prodrugs to estradiol, and are longer-lasting in comparison. Esters of estrone and estriol also exist and are employed in clinical medicine, ethinylestradiol is a more potent synthetic analogue of estradiol that is used widely in hormonal contraceptives
Estrogen
–
Estradiol. Note one
hydroxyl group attached to the D ring. The 'di' refers both to this hydroxyl and the one on the A ring (leftmost).
40.
L-DOPA
–
L-DOPA is an amino acid that is made and used as part of the normal biology of humans, some animals and plants. Some animals and humans make it via biosynthesis from the amino acid L-tyrosine, L-DOPA is the precursor to the neurotransmitters dopamine, norepinephrine, and epinephrine collectively known as catecholamines. Furthermore, L-DOPA itself mediates neurotrophic factor release by the brain, L-DOPA can be manufactured and in its pure form is sold as a psychoactive drug with the INN levodopa, trade names include Sinemet, Pharmacopa, Atamet, Stalevo, Madopar, and Prolopa. As a drug, it is used in the treatment of Parkinsons disease. L-DOPA has a counterpart with opposite chirality, D-DOPA, as is true for many molecules, the human body produces only one of these isomers. The enantiomeric purity of L-DOPA may be analyzed by determination of the rotation or by chiral thin-layer chromatography. L-DOPA crosses the protective barrier, whereas dopamine itself cannot. Thus, L-DOPA is used to increase dopamine concentrations in the treatment of Parkinsons disease and this treatment was made practical and proven clinically by George Cotzias and his coworkers, for which they won the 1969 Lasker Prize. Once L-DOPA has entered the central system, it is converted into dopamine by the enzyme aromatic L-amino acid decarboxylase. Pyridoxal phosphate is a cofactor in this reaction, and may occasionally be administered along with L-DOPA. Besides the central system, L-DOPA is also converted into dopamine from within the peripheral nervous system. Excessive peripheral dopamine signaling causes many of the side effects seen with sole L-DOPA administration. In addition, L-DOPA, co-administered with a peripheral DDCI, has been investigated as a treatment for restless leg syndrome. However, studies have demonstrated no clear picture of reduced symptoms, the two types of response seen with administration of L-DOPA are, The short-duration response is related to the half-life of the drug. The longer-duration response depends on the accumulation of effects over at least two weeks, during which ΔFosB accumulates in nigrostriatal neurons. In the treatment of Parkinsons disease, this response is evident only in early therapy, L-DOPA is produced from the amino acid L-tyrosine by the enzyme tyrosine hydroxylase. It is also the precursor for the monoamine or catecholamine neurotransmitters dopamine, norepinephrine, Dopamine is formed by the decarboxylation of L-DOPA by aromatic L-amino acid decarboxylase. L-DOPA can be metabolized by catechol-O-methyl transferase to 3-O-methyldopa
L-DOPA
–
L -DOPA
41.
Nicotine
–
Nicotine is a potent parasympathomimetic stimulant and an alkaloid found in the nightshade family of plants. Nicotine acts as a receptor agonist at most nicotinic acetylcholine receptors, Nicotine is found in the leaves of Nicotiana rustica in amounts of 2–14%, the tobacco plant Nicotiana tabacum, Duboisia hopwoodii and Asclepias syriaca. Nicotine constitutes approximately 0. 6–3. 0% of the dry weight of tobacco, less than one millionth of that concentration is found in edible Solanaceae such as eggplants and tomatoes. It functions as a chemical, consequently, nicotine was widely used as an insecticide in the past. An average cigarette yields about 2 mg of absorbed nicotine, and in lesser doses of that order and this stimulant effect is a contributing factor to the addictive properties of tobacco smoking. Nicotines addictive nature includes psychoactive effects, drug-reinforced behavior, compulsive use, relapse after abstinence, beyond addiction, both short and long-term nicotine exposure have not been established as dangerous to adults, except among certain vulnerable groups. At high-enough doses, nicotine is associated with poisonings and is potentially lethal, Nicotine as a tool for quitting smoking has a good safety history. There is inadequate research to show that nicotine itself is associated with cancer in humans, Nicotine in the form of nicotine replacement products is less of a cancer risk than smoking. Nicotine is linked to birth defects. During pregnancy, there are risks to the later in life for type 2 diabetes, obesity, hypertension, neurobehavioral defects, respiratory dysfunction. Nicotines mood-altering effects are different by report, in particular it is both a stimulant and a relaxant, first causing a release of glucose from the liver and epinephrine from the adrenal medulla, it causes stimulation. Users report feelings of relaxation, sharpness, calmness, and alertness, like any stimulant, it may very rarely cause the often uncomfortable akathisia. By reducing the appetite and raising the metabolism, some smokers may lose weight as a consequence, Nicotine also extends the duration of positive effects of dopamine and increases the sensitivity of the brains reward system to rewarding stimuli. Most cigarettes contain 1–3 milligrams of inhalable nicotine, studies suggest that when smokers wish to achieve a stimulating effect, they take short quick puffs, which produce a low level of blood nicotine. At very high doses it dampens neuronal activity, the primary therapeutic use of nicotine is in treating nicotine dependence in order to eliminate smoking with the damage it does to health. Controlled levels of nicotine are given to patients through gums, dermal patches, lozenges, studies have found that these therapies increase the chance of success of quitting by 50 to 70%, though reductions in the population as a whole have not been demonstrated. Nicotine is frequently used for its effects on cognition, alertness. Nicotine is commonly consumed as a drug for its stimulant effects
Nicotine
–
A 21 mg patch applied to the left arm. The
Cochrane Collaboration finds that
nicotine replacement therapy increases a quitter's chance of success by 50% to 70%.
Nicotine
–
Nicotine
Nicotine
–
Types
42.
Propranolol
–
Propranolol is a medication of the beta blocker type. It is used to high blood pressure, a number of types of irregular heart rate, thyrotoxicosis, capillary hemangiomas, performance anxiety. It is used to prevent migraine headaches, and to prevent further problems in those with angina or previous heart attacks. It can be taken by mouth or by injection into a vein, the formulation that is taken by mouth comes in short acting and long acting versions. Propranolol appears in the blood after 30 minutes and has an effect between 60 and 90 minutes when taken by mouth. Common side effects include nausea, abdominal pain, and constipation and it should not be used in those with an already slow heart rate and most of those with heart failure. Quickly stopping the medication in those with coronary artery disease may worsen symptoms and it may worsen the symptoms of asthma. Greater care is recommended in those with liver or kidney problems, Propranolol may cause harmful effects in the baby if taken during pregnancy. Its use during breastfeeding is safe, but the baby should be monitored for side effects. It is a beta blocker which works by blocking β-adrenergic receptors. It is on the World Health Organizations List of Essential Medicines, Propranolol is available as a generic medication. The wholesale cost in the world is between 0.24 and 2.16 USD per month as of 2014. In the United States it costs about 15 USD per month at a typical dose and it is occasionally used to treat performance anxiety. Evidence to support the use in other anxiety disorders is poor, Propranolol works to inhibit the actions of norepinephrine, a neurotransmitter that enhances memory consolidation. Individuals given propranolol immediately after trauma experienced fewer stress-related symptoms and lower rates of PTSD than respective control groups who did not receive the drug and this treatment shows promise as being superior to corticosteroids when treating IHs. Extensive clinical case evidence and a controlled trial support its efficacy. Dreaming was reduced and increased awakening, adverse drug reactions associated with propranolol therapy are similar to other lipophilic beta blockers. β-blocking agents in general reduce perfusion of the placenta which may lead to adverse outcomes for the neonate, including pulmonary or cardiac complications, the newborn may experience additional adverse effects such as hypoglycemia and bradycardia
Propranolol
43.
Deep sleep
–
Slow-wave sleep, often referred to as deep sleep, consists of stage three of non-rapid eye movement sleep, according to the Rechtschaffen & Kales standard of 1968. There is not a distinction between stages three and four. Stage three has 20-50 percent delta activity, whereas stage four has more than 50 percent, as of 2008, the American Academy of Sleep Medicine has discontinued the use of stage four, such that the previous stages three and four now are combined as stage three. An epoch which consists of 20% or more slow-wave sleep is now considered to be stage three and this period of sleep is called slow-wave sleep because the EEG activity is synchronized, producing slow waves with a frequency of less than 1 Hz and a relatively high amplitude. The first section of the wave signifies a state, which is an inhibition period in which the neurons in the neocortex are silent. This is the period when the neurons are able to rest. The second section of the wave signifies an up state, which is a period in which the neurons fire briefly at a high rate. The former state is a phase and the latter is a depolarizing phase. The principal characteristics during slow-wave sleep that contrast with REM sleep are moderate muscle tone, slow or absent eye movement, slow-wave sleep is considered important to consolidate new memories. This is sometimes referred to as sleep-dependent memory processing, impaired memory consolidation has been effected in individuals with primary insomnia who thus do not perform as well as normal patients in memory tasks following a period of sleep. Furthermore, slow-wave sleep improves declarative memory, a central model has been hypothesized that the long-term memory storage is facilitated by an interaction between the hippocampal and neocortical networks. In several studies, after the subjects have had training to learn a declarative memory task and this is the result of the spontaneously occurring wave oscillations that account for the intracellular recordings from thalamic and cortical neurons. Sleep deprivation studies with humans suggest that the function of slow-wave sleep may be to allow the brain to recover from its daily activities. Glucose metabolism in the brain increases as a result of tasks that demand mental activity, another function affected by slow-wave sleep is the secretion of growth hormone, which is always greatest during this stage. It is also thought to be responsible for a decrease in sympathetic, the highest arousal thresholds are observed in deep sleep. This phenomenon has been called sleep inertia, after sleep deprivation there is a sharp rebound of SWS, that is, the following bout of sleep will include more and deeper SWS than normal. The duration of sleep is determined by the previous duration of this stage as well as the duration of prior wakefulness. Some of the known to increase slow-wave sleep in the sleep period that follows them include body heating
Deep sleep
–
Polysomnogram demonstrating SWS, stage four. High amplitude EEG is highlighted in red.
44.
Fasting
–
Fasting is a willing abstinence or reduction from some or all food, drink, or both, for a period of time. An absolute fast is normally defined as abstinence from all food and liquid for a period, usually a period of 24 hours. Water fasting allows drinking water but nothing else, other fasts may be partially restrictive, limiting only particular foods or substances. A fast may also be intermittent in nature, Fasting practices may preclude intercourse and other activities as well as food. In a physiological context, fasting may refer to the status of a person who has not eaten overnight. Several metabolic adjustments occur during fasting, and some tests are used to determine a fasting state. For example, a person is assumed to be fasting after 8–12 hours from their last meal, metabolic changes toward the fasting state begin after absorption of a meal, post-absorptive state is synonymous with this usage, in contrast to the postprandial state of ongoing digestion. A diagnostic fast refers to prolonged fasting conducted under observation for investigation of a problem, many people may also fast as part of a medical procedure or check-up such as a colonoscopy. Fasting is also a part of religious observances. Fasting is often practiced prior to surgery or other procedures that require general anesthetics because of the risk of aspiration of gastric contents after induction of anesthesia. Additionally, certain tests, such as cholesterol testing or certain blood glucose measurements require fasting for several hours so that a baseline can be established. In the case of a panel, failure to fast for a full 12 hours will guarantee an elevated triglyceride measurement. Fasting is of no help in preventing or treating cancer. Fasting can help alleviate symptoms of depression. However the psychological effects may include anxiety and depression. Fasting will lead to weight loss, using fasting for weight loss is considered dangerous. It has been argued that fasting makes one better appreciate food, Fasting is often used as a tool to make a political statement, to protest, or to bring awareness to a cause. A hunger strike is a method of non-violent resistance in which participants fast as an act of political protest, or to provoke feelings of guilt, a spiritual fast incorporates personal spiritual beliefs with the desire to express personal principles, sometimes in the context of a social injustice
Fasting
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The Buddha emaciated after undergoing severe ascetic practises.
Gandhara, 2 – 3rd century CE.
British Museum.
Fasting
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Ending the fast at a mosque
45.
Exercise
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Physical exercise is any bodily activity that enhances or maintains physical fitness and overall health and wellness. Frequent and regular physical exercise boosts the immune system and helps prevent diseases of such as cardiovascular disease, type 2 diabetes. Childhood obesity is a global concern, and physical exercise may help decrease some of the effects of childhood. Some care providers call exercise the miracle or wonder drug—alluding to the variety of benefits that it can provide for many individuals. Aside from the advantages, these benefits may include different social rewards for staying active while enjoying the environment of one’s culture. Many individuals choose to exercise publicly outdoors where they can congregate in groups, socialize, in the United Kingdom two to four hours of light activity are recommended during working hours. The goal of aerobic exercise is to increase cardiovascular endurance, examples of aerobic exercise include cycling, swimming, brisk walking, skipping rope, rowing, hiking, playing tennis, continuous training, and long slow distance training. Anaerobic exercise, which includes strength and resistance training, can firm, strengthen, and tone muscles, as well as improve bone strength, balance, examples of strength moves are push-ups, pull-ups, lunges, and bicep curls using dumbbells. Anaerobic exercise also include training, functional training, eccentric training, Interval training, sprinting. Flexibility exercises stretch and lengthen muscles, activities such as stretching help to improve joint flexibility and keep muscles limber. The goal is to improve the range of motion which can reduce the chance of injury, Physical exercise can also include training that focuses on accuracy, agility, power, and speed. Sometimes the terms dynamic and static are used, dynamic exercises such as steady running, tend to produce a lowering of the diastolic blood pressure during exercise, due to the improved blood flow. Conversely, static exercise can cause the pressure to rise significantly. Some studies indicate that exercise may increase life expectancy and the quality of life. People who participate in moderate to high levels of exercise have a lower mortality rate compared to individuals who by comparison are not physically active. Moderate levels of exercise have been correlated with preventing aging by reducing inflammatory potential, the majority of the benefits from exercise are achieved with around 3500 metabolic equivalent minutes per week. A lack of physical activity causes approximately 6% of the burden of disease from coronary disease, 7% of type 2 diabetes, 10% of breast cancer. Overall, physical inactivity causes 9% of premature mortality worldwide, individuals can increase fitness following increases in physical activity levels
Exercise
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A
U.S. Marine participates in a
triathlon at
Catoctin Mountain in 2005
Exercise
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Indian wrestler exercising near
Varanasi
Exercise
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A common
elliptical training machine
Exercise
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US Marines exercising on the
USS Bataan
46.
Negative feedback
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Whereas positive feedback tends to lead to instability via exponential growth, oscillation or chaotic behavior, negative feedback generally promotes stability. Negative feedback tends to promote a settling to equilibrium, and reduces the effects of perturbations, Negative feedback loops in which just the right amount of correction is applied with optimum timing can be very stable, accurate, and responsive. General negative feedback systems are studied in control systems engineering, in the invisible hand of the market metaphor of economic theory, reactions to price movements provide a feedback mechanism to match supply and demand. In centrifugal governors, negative feedback is used to maintain a near-constant speed of an engine, in a Steering engine, power assistance is applied to the rudder with a feedback loop, to maintain the direction set by the steersman. In servomechanisms, the speed or position of an output, as determined by a sensor, is compared to a set value, and any error is reduced by negative feedback to the input. In analog computing feedback around operational amplifiers is used to generate mathematical functions such as addition, subtraction, integration, differentiation, logarithm, in a phase locked loop feedback is used to maintain a generated alternating waveform in a constant phase to a reference signal. In many implementations the generated waveform is the output, but when used as a demodulator in a FM radio receiver, if there is a frequency divider between the generated waveform and the phase comparator, the device acts as a frequency multiplier. In organisms, feedback enables various measures to be maintained within a range by homeostatic processes. Negative feedback as a technique may be seen in the refinements of the water clock introduced by Ktesibios of Alexandria in the 3rd century BCE. Self-regulating mechanisms have existed since antiquity, and were used to maintain a constant level in the reservoirs of water clocks as early as 200 BCE, Negative feedback was implemented in the 17th Century. The term feedback was well established by the 1920s, in reference to a means of boosting the gain of an electronic amplifier, friis and Jensen described this action as positive feedback and made passing mention of a contrasting negative feed-back action in 1924. Karl Küpfmüller published papers on an automatic gain control system. Nyquist and Bode built on Black’s work to develop a theory of amplifier stability, early researchers in the area of cybernetics subsequently generalized the idea of negative feedback to cover any goal-seeking or purposeful behavior. All purposeful behavior may be considered to require negative feed-back, for understanding the general principles of dynamic systems, therefore, the concept of feedback is inadequate in itself. What is important is that complex systems, richly cross-connected internally, have complex behaviors, to reduce confusion, later authors have suggested alternative terms such as degenerative, self-correcting, balancing, or discrepancy-reducing in place of negative. In many physical and biological systems, qualitatively different influences can oppose each other, for example, in biochemistry, one set of chemicals drives the system in a given direction, whereas another set of chemicals drives it in an opposing direction. If one or both of these influences are non-linear, equilibrium point result. In biology, this process is referred to as homeostasis, whereas in mechanics
Negative feedback
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Feedback loops in the human body
Negative feedback
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The
fly-ball governor is an early example of negative feedback.
47.
Glucocorticoid
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Glucocorticoids are a class of corticosteroids, which are a class of steroid hormones. Glucocorticoids are corticosteroids that bind to the receptor, that is present in almost every vertebrate animal cell. The name glucocorticoid is composed from its role in regulation of metabolism, synthesis in the adrenal cortex. A less common synonym is glucocorticosteroid, gCs are part of the feedback mechanism in the immune system which reduces certain aspects of immune function, such as reduction of inflammation. They are therefore used in medicine to treat diseases caused by an immune system, such as allergies, asthma, autoimmune diseases. GCs have many effects, including potentially harmful side effects. They also interfere with some of the mechanisms in cancer cells. This includes, inhibitory effects on lymphocyte proliferation as in the treatment of lymphomas and leukemias, gCs affect cells by binding to the glucocorticoid receptor. Glucocorticoids are distinguished from mineralocorticoids and sex steroids by their specific receptors, target cells, in technical terms, corticosteroid refers to both glucocorticoids and mineralocorticoids, but is often used as a synonym for glucocorticoid. Glucocorticoids are chiefly produced in the zona fasciculata of the adrenal cortex, cortisol is the most important human glucocorticoid. It is essential for life, and it regulates or supports a variety of important cardiovascular, metabolic, immunologic, glucocorticoid effects may be broadly classified into two major categories, immunological and metabolic. In addition, glucocorticoids play important roles in development and body fluid homeostasis. As discussed in detail below, glucocorticoids function through interaction with the glucocorticoid receptor. Down-regulate the expression of proinflammatory proteins, glucocorticoids are also shown to play a role in the development and homeostasis of T lymphocytes. This has been shown in mice with either increased or decreased sensitivity of T cell lineage to glucocorticoids. The name glucocorticoid derives from early observations that these hormones were involved in glucose metabolism, in the fasted state, cortisol stimulates several processes that collectively serve to increase and maintain normal concentrations of glucose in blood. Enhancing the expression of enzymes involved in gluconeogenesis is probably the best-known metabolic function of glucocorticoids, mobilization of amino acids from extrahepatic tissues, These serve as substrates for gluconeogenesis. Excessive glucocorticoid levels resulting from administration as a drug or hyperadrenocorticism have effects on many systems, some examples include inhibition of bone formation, suppression of calcium absorption, delayed wound healing, muscle weakness, and increased risk of infection
Glucocorticoid
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Chemical structure of
cortisol, a glucocorticoid
48.
Dihydrotestosterone
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Dihydrotestosterone, or 5α-dihydrotestosterone, also known as 5α-androstan-17β-ol-3-one, is an endogenous androgen sex steroid and hormone. The enzyme 5α-reductase catalyzes the formation of DHT from testosterone in certain tissues including the prostate gland, seminal vesicles, epididymides, skin, hair follicles, liver and this enzyme mediates reduction of the C4-5 double bond of testosterone. Relative to testosterone, DHT is considerably more potent as an agonist of the androgen receptor. DHT has an affinity of 0.25 to 0.5 nM for the human AR, the dissociation rate of DHT from the AR is 5-fold slower than that of testosterone. The EC50 of DHT for activation of the AR is 0.13 nM, in bioassays, DHT has been found to be 2. 5- to 10-fold more potent than testosterone. The terminal half-life of DHT in the body is longer than that of testosterone, a study of transdermal DHT and testosterone treatment reported terminal half-lives of 2.83 hours and 1.29 hours, respectively. An example illustrating the significance of DHT for the development of sex characteristics is congenital 5α-reductase type II deficiency. This genetic mutation can result in pseudohermaphroditism, the condition typically presents with underdeveloped male genitalia and prostate. Males with this condition are often raised as girls due to their lack of male genitalia. At the onset of puberty, although their DHT levels remain very low and their musculature develops like that of other male adults. After puberty, men with this condition have a deficiency of pubic and body hair. They also reportedly have no incidence of prostate cancer, unlike other androgens such as testosterone, DHT cannot be converted by the enzyme aromatase into an estrogen like estradiol. In the case of female androgenic alopecia, on the hand, the situation is more complex. Women with increased levels of DHT may develop symptoms of such as certain androgynous masculine secondary sex characteristics, including a deepened voice. In men, prostate growth and differentiation are highly dependent on androgens, especially DHT, both finasteride and dutasteride are approved for the treatment of BPH and androgenic alopecia. Dutasteride is three times more potent than finasteride in inhibiting the type II enzyme and 100 times more potent than finasteride in inhibiting the type I form of the DHT-producing enzyme, both finasteride and dutasteride are potent inhibitors of the third isotype of the enzyme. Acne, hirsutism, and seborrhea are also DHT-related conditions, in addition, antiandrogens like cyproterone acetate, spironolactone, and bicalutamide, as well as estrogens like ethinylestradiol, may also be used to treat these conditions. DHT is synthesized from testosterone by the enzyme 5α-reductase, in males, approximately 5% of testosterone undergoes 5α-reduction into DHT
Dihydrotestosterone
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Dihydrotestosterone
49.
Endocrine disruptor
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Endocrine disruptors are chemicals that can interfere with endocrine systems at certain doses. These disruptions can cause tumors, birth defects, and other developmental disorders. Any system in the controlled by hormones can be derailed by hormone disruptors. The critical period of development for most organisms is between the transition from an egg into a fully formed infant. As the cells begin to grow and differentiate, there are critical balances of hormones, therefore, a dose of disrupting chemicals may do substantial damage to a developing fetus. The same dose may not significantly affect adult mothers and they are sometimes also referred to as hormonally active agents, endocrine disrupting chemicals, or endocrine disrupting compounds. Studies in cells and laboratory animals have shown that EDCs can cause adverse effects in animals. The term endocrine disruptor is often used as synonym for xenohormone although the latter can mean any naturally occurring or artificially produced compound showing hormone-like properties, the term endocrine disruptor was coined at the Wingspread Conference Centre in Wisconsin, in 1991. One of the papers on the phenomenon was by Theo Colborn in 1993. In this paper, she stated that environmental chemicals disrupt the development of the system, and that effects of exposure during development are often permanent. ”The statement noted that it is difficult to show that endocrine disruptors cause human diseases. A concurrent statement expresses policy concerns, some are pervasive and widely dispersed in the environment and may bio-accumulate. Others are rapidly degraded in the environment or human body or may be present for short periods of time. Prior to its ban in the early 1970s, doctors prescribed DES to as many as five million pregnant women to block spontaneous abortion and it was discovered after the children went through puberty that DES affected the development of the reproductive system and caused vaginal cancer. Aquatic life subjected to endocrine disruptors in an urban effluent have experienced decreased levels of serotonin, the team pointed to wide gaps in knowledge and called for more research to obtain a fuller picture of the health and environmental impacts of endocrine disruptors. Research, more evidence is needed to identify the effects of mixtures of EDCs on humans and wildlife to which humans. Reporting, many sources of EDCs are not known because of insufficient reporting and information on chemicals in products, materials, collaboration, more data sharing between scientists and between countries can fill gaps in data, primarily in developing countries and emerging economies. Endocrine systems are found in most varieties of animals, the endocrine system consists of glands that secrete hormones, and receptors that detect and react to the hormones. Hormones travel throughout the body and act as chemical messengers, hormones interface with cells that contain matching receptors in or on their surfaces
Endocrine disruptor
. PMID 21584161. doi:10.4103/2230-8210.77573.
