1.
Inflammation
–
The classical signs of inflammation are heat, pain, redness, swelling, and loss of function. Inflammation is a response, and therefore it is considered as a mechanism of innate immunity, as compared to adaptive immunity. Too little inflammation could lead to tissue destruction by the harmful stimulus. In contrast, chronic inflammation may lead to a host of diseases, such as hay fever, periodontitis, atherosclerosis, rheumatoid arthritis, Inflammation is therefore normally closely regulated by the body. Inflammation can be classified as acute or chronic. Acute inflammation is the response of the body to harmful stimuli and is achieved by the increased movement of plasma. A series of biochemical events propagates and matures the inflammatory response, involving the vascular system, the immune system. Inflammation is not a synonym for infection, Inflammation on the other hand describes purely the bodys immunovascular response, whatever the cause may be. But because of how often the two are correlated, words ending in the suffix -itis are sometimes described as referring to infection. There are also situations where microbial invasion does not result in classic inflammatory response—for example, parasitosis. Acute inflammation is a process, usually appearing within a few minutes or hours. It involves a coordinated and systemic mobilisation response locally of various immune, endocrine, in a normal healthy response, it becomes activated, clears the pathogen and begins a repair process and then ceases. It is characterized by five signs, An acronym that may be used to remember the key symptoms is PRISH, for pain, redness, immobility, swelling. Loss of function has multiple causes, Acute inflammation of the lung does not cause pain unless the inflammation involves the parietal pleura, which does have pain-sensitive nerve endings. PAMPs are compounds that are associated with pathogens, but which are distinguishable from host molecules. DAMPs are compounds that are associated with host-related injury and cell damage, at the onset of an infection, burn, or other injuries, these cells undergo activation and release inflammatory mediators responsible for the clinical signs of inflammation. Vasodilation and its resulting increased blood flow causes the redness and increased heat, increased permeability of the blood vessels results in an exudation of plasma proteins and fluid into the tissue, which manifests itself as swelling. Some of the released mediators such as increase the sensitivity to pain
2.
Platelet
–
Platelets, also called thrombocytes, are a component of blood whose function is to stop bleeding by clumping and clotting blood vessel injuries. Platelets have no nucleus, they are fragments of cytoplasm that are derived from the megakaryocytes of the bone marrow. These unactivated platelets are biconvex discoid structures, 2–3 µm in greatest diameter, platelets are found only in mammals, whereas in other animals thrombocytes circulate as intact mononuclear cells. On a stained blood smear, platelets appear as purple spots. The smear is used to examine platelets for size, shape, qualitative number, the ratio of platelets to red blood cells in a healthy adult is 1,10 to 1,20. The main function of platelets is to contribute to hemostasis, the process of stopping bleeding at the site of interrupted endothelium and they gather at the site and unless the interruption is physically too large, they plug the hole. First, platelets attach to substances outside the interrupted endothelium, adhesion, second, they change shape, turn on receptors and secrete chemical messengers, activation. Third, they connect to each other through receptor bridges, aggregation, formation of this platelet plug is associated with activation of the coagulation cascade with resultant fibrin deposition and linking. These processes may overlap, the spectrum is from a predominantly platelet plug, or white clot to a predominantly fibrin clot, the final result is the clot. Some would add the subsequent clot retraction and platelet inhibition as fourth and fifth steps to the completion of the process, low platelet concentration is thrombocytopenia and is due to either decreased production or increased destruction. Elevated platelet concentration is thrombocytosis and is either congenital, reactive, or due to unregulated production, a disorder of platelet function is a thrombocytopathy. An arterial thrombus may partially obstruct blood flow, causing downstream ischemia, or may completely obstruct it, george Gulliver in 1841 drew pictures of platelets using the twin lens microscope invented in 1830 by Joseph Jackson Lister. This microscope improved resolution sufficiently to make it possible to see platelets for the first time, william Addison in 1842 drew pictures of a platelet-fibrin clot. Lionel Beale in 1864 was the first to publish a drawing showing platelets, max Schultze in 1865 described what he called spherules, which he noted were much smaller than red blood cells, occasionally clumped, and were sometimes found in collections of fibrin material. Queens College, Birmingham physician Dr Richard Hill Norris was the first to describe the action of platelets in 1880, giulio Bizzozero in 1882 studied the blood of amphibians microscopically in vivo. He named Schultzs spherules piastrine, little plates, william Osler observed them and, in published lectures in 1886, called them a third corpuscle and a blood plaque and described them as a colorless protoplasmic disc. Thrombocytes are cells found in the blood of non-mammalian vertebrates and they are the functional equivalents of platelets, but circulate as intact mononuclear cells, and are not simply cytoplasmic fragments of bone marrow megakaryocytes. In some contexts, the thrombus is used interchangeably with the word clot
3.
Microorganism
–
A microorganism or microbe is a microscopic organism, which may be single-celled or multicellular. The study of microorganisms is called microbiology, a subject that began with the discovery of microorganisms in 1674 by Antonie van Leeuwenhoek, microorganisms are very diverse and include all bacteria, archaea and most protozoa. This group also contains some fungi, algae, and some such as rotifers. Many macroscopic animals and plants have microscopic juvenile stages, some microbiologists classify viruses and viroids as microorganisms, but others consider these as nonliving. In July 2016, scientists identified a set of 355 genes from the last universal ancestor of all life, including microorganisms. Microorganisms, under certain test conditions, have observed to thrive in the vacuum of outer space. Microorganisms likely far outweigh all other living things combined, the mass of prokaryote microorganisms including the bacteria and archaea may be as much as 0.8 trillion tons of carbon, out of the total biomass of between 1 and 4 trillion tons. Microorganisms appear to thrive in the Mariana Trench, the deepest spot in the Earths oceans, in August 2014, scientists confirmed the existence of microorganisms living 800 m below the ice of Antarctica. According to one researcher, You can find microbes everywhere — theyre extremely adaptable to conditions, microorganisms are crucial to nutrient recycling in ecosystems as they act as decomposers. As some microorganisms can fix nitrogen, they are a part of the nitrogen cycle. Microorganisms are also exploited in biotechnology, both in food and beverage preparation, and in modern technologies based on genetic engineering. A small proportion of microorganisms are pathogenic, causing disease and even death in plants, Robert Hooke coined the term cell after viewing plant cells under his microscope. Antonie Van Leeuwenhoek was one of the first people to observe microorganisms in 1673, later, in the 19th century, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation. In 1876 Robert Koch discovered that microorganisms cause diseases, single-celled microorganisms were the first forms of life to develop on Earth, approximately 3–4 billion years ago. Further evolution was slow, and for about 3 billion years in the Precambrian eon, so, for most of the history of life on Earth, the only forms of life were microorganisms. Bacteria, algae and fungi have been identified in amber that is 220 million years old, microorganisms tend to have a relatively fast rate of evolution. Most microorganisms can reproduce rapidly, and bacteria are able to freely exchange genes through conjugation, transformation and transduction. This rapid evolution is important in medicine, as it has led to the development of multidrug resistant pathogenic bacteria, superbugs, the possible existence of microorganisms was discussed for many centuries before their discovery in the 17th century
4.
Hemodialysis
–
Hemodialysis, also spelled haemodialysis, commonly called kidney dialysis or simply dialysis, is a process of purifying the blood of a person whose kidneys are not working normally. This type of dialysis achieves the extracorporeal removal of waste such as creatinine and urea. Hemodialysis is one of three renal replacement therapies, an alternative method for extracorporeal separation of blood components such as plasma or cells is apheresis. Hemodialysis can be an outpatient or inpatient therapy, routine hemodialysis is conducted in a dialysis outpatient facility, either a purpose built room in a hospital or a dedicated, stand-alone clinic. Less frequently hemodialysis is done at home, Hemodialysis is the choice of renal replacement therapy for patient who need dialysis acutely, and for many patients as maintenance therapy. It provides excellent, rapid clearance of solutes, a nephrologist decides when hemodialysis is needed and the various parameters for a dialysis treatment. These include frequency, length of treatment, and the blood and dialysis solution flow rates. The composition of the solution is also sometimes adjusted in terms of its sodium and potassium. In general, the larger the size of an individual. In North America and the UK, 3-4 hour treatments given 3 times a week are typical, twice-a-week sessions are limited to patients who have a substantial residual kidney function. Four sessions per week are often prescribed for patients, as well as patients who have trouble with fluid overload. Finally, there is growing interest in short daily home hemodialysis, there is also interest in nocturnal dialysis, which involves dialyzing a patient, usually at home, for 8–10 hours per night, 3-6 nights per week. Nocturnal in-center dialysis, 3-4 times per week, is offered at a handful of dialysis units in the United States. Side effects caused by removing too much fluid and/or removing fluid too rapidly include low blood pressure, fatigue, chest pains, leg-cramps, nausea and headaches. These symptoms can occur during the treatment and can persist post treatment, the severity of these symptoms is usually proportionate to the amount and speed of fluid removal. However, the impact of an amount or rate of fluid removal can vary greatly from person to person. The risk of infection varies depending on the type of access used, bleeding may also occur, again the risk varies depending on the type of access used. Infections can be minimized by strictly adhering to infection control best practices, heparin is the most commonly used anticoagulant in hemodialysis, as it is generally well tolerated and can be quickly reversed with protamine sulfate
5.
Ultrasound
–
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is no different from normal sound in its physical properties and this limit varies from person to person and is approximately 20 kilohertz in healthy, young adults. Ultrasound devices operate with frequencies from 20 kHz up to several gigahertz, Ultrasound is used in many different fields. Ultrasonic devices are used to detect objects and measure distances, Ultrasound imaging or sonography is often used in medicine. In the nondestructive testing of products and structures, ultrasound is used to detect invisible flaws, industrially, ultrasound is used for cleaning, mixing, and to accelerate chemical processes. Animals such as bats and porpoises use ultrasound for locating prey, scientist are also studying ultrasound using graphene diaphragms as a method of communication. Acoustics, the science of sound, starts as far back as Pythagoras in the 6th century BC, echolocation in bats was discovered by Lazzaro Spallanzani in 1794, when he demonstrated that bats hunted and navigated by inaudible sound and not vision. The first technological application of ultrasound was an attempt to detect submarines by Paul Langevin in 1917, the piezoelectric effect, discovered by Jacques and Pierre Curie in 1880, was useful in transducers to generate and detect ultrasonic waves in air and water. Ultrasound is defined by the American National Standards Institute as sound at frequencies greater than 20 kHz, in air at atmospheric pressure ultrasonic waves have wavelengths of 1.9 cm or less. The upper frequency limit in humans is due to limitations of the middle ear, auditory sensation can occur if high‐intensity ultrasound is fed directly into the human skull and reaches the cochlea through bone conduction, without passing through the middle ear. Children can hear some high-pitched sounds that older adults cannot hear, the Mosquito is an electronic device that uses a high pitched frequency to deter loitering by young people. Bats use a variety of ultrasonic ranging techniques to detect their prey and they can detect frequencies beyond 100 kHz, possibly up to 200 kHz. Many insects have good hearing and most of these are nocturnal insects listening for echolocating bats. This includes many groups of moths, beetles, praying mantids, upon hearing a bat, some insects will make evasive manoeuvres to escape being caught. Ultrasonic frequencies trigger an action in the noctuid moth that cause it to drop slightly in its flight to evade attack. Tiger moths also emit clicks which may disturb bats echolocation, dogs and cats hearing range extends into the ultrasound, the top end of a dogs hearing range is about 45 kHz, while a cats is 64 kHz. The wild ancestors of cats and dogs evolved this higher hearing range to hear sounds made by their preferred prey. A dog whistle is a whistle that emits ultrasound, used for training and calling dogs, porpoises have the highest known upper hearing limit, at around 160 kHz
6.
Drug injection
–
Drug injection is a method of introducing a drug into the bloodstream via a hollow hypodermic needle and a syringe, which is pierced through the skin into the body. It often applies to substance dependence and recreational drug use and this act is often colloquially referred to as slamming, shooting, banging, pinning, or jacking-up, often depending on the specific drug subculture in which the term is used. Although there are methods of taking drugs, injection is favoured by some users as the full effects of the drug are experienced very quickly, typically in five to ten seconds. This shorter, more intense high can lead to a dependency—both physical, as of 2004, there were 13.2 million people worldwide who used injection drugs, of which 22% are from developed countries. This means that the drug will have a strong and rapid onset. With some drugs, this can produce sensations not found with other routes of administration, more efficient usage — A smaller amount is enough as injection means that more of the drug will reach the brain than with other methods. This is because the defenses and detoxifying mechanisms are bypassed. This means that it requires less drug to achieve the same effect, abscessed infections of injection sites are caused by lack of hygiene and a lack of aseptic technique. Increased chance of overdose — Because IV injection delivers a dose of drug straight into the bloodstream, in addition, because of the rapid onset of intravenous drugs, overdose can occur very quickly, requiring immediate action. Scarring of the peripheral veins — This arises from the use of blunt injecting equipment and this is particularly common with users who have been injecting while in jail and re-use disposable syringes sometimes hundreds of times. IV drug use for an extended period may result in collapsed veins, though rotating sites and allowing time to heal before reuse may decrease the likelihood of this occurring, collapse of peripheral veins may still occur with prolonged IV drug use. IV drug users are among the most difficult patient populations to obtain blood-specimens from because of peripheral venous scarring, the darkening of the veins due to scarring and toxin buildup produce tracks along the length of the veins and are known as track marks. Arterial damage — Arterial pseudoaneurysms may form at sites, which can rupture, potentially resulting in hemorrhage, distal ischemia. Inadvertent intra-arterial injection can also result in endarteritis and thrombosis, with similar consequences. Increased chance of addiction — The heightened effect of administering drugs intravenously can make the chances of more likely. Social stigma — In many societies, there is a stigma attached to IV drug use, in addition to the more general stigma around illegal drug use. The drug—usually in a powder or crystal form—is dissolved in water, normally in a spoon, tin, bottle cap, cylindrical metal containers—sometimes called cookers—are provided by needle exchange programs. Users draw the required amount of water into a syringe and squirt this over the drugs, the solution is then mixed and heated from below if necessary
7.
Anthony S. Fauci
–
He is of Italian descent and grew up Catholic. He graduated from Regis High School in New York City and went on to attend the College of the Holy Cross and he then completed an internship and residency at The New York Hospital-Cornell Medical Center. In 1968, he came to the National Institutes of Health as an associate in the Laboratory of Clinical Investigation in NIAID. In 1974, he became Head of the Clinical Physiology Section, LCI, and in 1980 was appointed Chief of the Laboratory of Immunoregulation, a position he still holds. In 1984, he became Director of NIAID, which has the responsibility for a research portfolio of basic and applied research on infectious. He has developed therapies for formerly fatal diseases such as polyarteritis nodosa, granulomatosis with polyangiitis, Fauci has made influential contributions to the understanding of how HIV destroys the bodys defenses leading to the progression to AIDS. He also has outlined the mechanisms of induction of HIV expression by endogenous cytokines, Fauci has played an important role in developing strategies for the therapy and immune reconstitution of patients with this disease, as well as for a vaccine to prevent HIV infection. His current research is concentrated on identifying the nature of the mechanisms of HIV infection. In 2003, the Institute for Scientific Information indicated that Fauci was the 13th most-cited scientist during the period from 1983 to 2002. He was the ninth most-cited scientist in immunology in the period January 1993 to June 30,2003, flemming Award Fauci has been a visiting professor at many medical centers, and has received 30 honorary doctorate degrees from universities in the United States and abroad. On October 16,2014, in a United States Congressional hearing regarding the Ebola virus crisis, Dr. Dr. Fauci AS, Dale DC, glucocorticosteroid therapy, mechanisms of action and clinical considerations. Fauci AS, Haynes B, Katz P, the spectrum of vasculitis, clinical, pathologic, immunologic and therapeutic considerations. Fauci AS, Haynes BF, Katz P, Wolff SM, wegeners granulomatosis, prospective clinical and therapeutic experience with 85 patients for 21 years. Fauci AS, Macher AM, Longo DL, et al, acquired immunodeficiency syndrome, epidemiologic, clinical, immunologic, and therapeutic considerations. CS1 maint, Explicit use of et al, the human immunodeficiency virus, infectivity and mechanisms of pathogenesis. Pantaleo G, Graziosi C, Fauci AS, New concepts in the immunopathogenesis of human immunodeficiency virus infection. Latent reservoirs of HIV, obstacles to the eradication of virus, proc Natl Acad Sci U S A.96, 10958–61. Morens DM, Folkers GK, Fauci AS, the challenge of emerging and re-emerging infectious diseases
8.
Streptococcus
–
Streptococcus is a genus of coccus Gram-positive bacteria belonging to the phylum Firmicutes and the order Lactobacillales. Cell division in this genus occurs along an axis in these bacteria, thus they grow in chains or pairs, hence the name—from Greek στρεπτός streptos, meaning easily bent or twisted. Most are oxidase-negative and catalase-negative, and many are facultative anaerobes, in 1984, many bacteria formerly considered Streptococcus were separated out into the genera Enterococcus and Lactococcus. Currently, over 50 species are recognised in this genus, however, many streptococcal species are not pathogenic, and form part of the commensal human microbiota of the mouth, skin, intestine, and upper respiratory tract. Furthermore, streptococci are an ingredient in producing Emmentaler cheese. Species of Streptococcus are classified based on their hemolytic properties, alpha-hemolytic species cause oxidization of iron in hemoglobin molecules within red blood cells, giving it a greenish color on blood agar. Beta-hemolytic species cause complete rupture of red blood cells, on blood agar, this appears as wide areas clear of blood cells surrounding bacterial colonies. Beta-hemolytic streptococci are further classified by Lancefield grouping, a serotype classification, the 20 described serotypes are named Lancefield groups A to V. In the medical setting, the most important groups are the alpha-hemolytic streptococci S. pneumoniae and Streptococcus viridans group, table, Medically relevant streptococci When alpha hemolysis is present, the agar under the colony is dark and greenish. Streptococcus pneumoniae and a group of oral streptococci display alpha hemolysis and this is sometimes called green hemolysis because of the color change in the agar. Other synonymous terms are incomplete hemolysis and partial hemolysis, alpha hemolysis is caused by hydrogen peroxide produced by the bacterium, oxidizing hemoglobin to green methemoglobin. S. pneumoniae, is a cause of bacterial pneumonia and occasional etiology of otitis media, sinusitis, meningitis. Inflammation is thought to be the cause of how pneumococci cause disease. The viridans streptococci are a group of commensal bacteria, that are either α-hemolytic, producing a green coloration on blood agar plates. Beta hemolysis, sometimes called complete hemolysis, is a complete lysis of red cells in the media around and under the colonies, streptolysin, an exotoxin, is the enzyme produced by the bacteria which causes the complete lysis of red blood cells. SLS affects immune cells, including polymorphonuclear leukocytes and lymphocytes, and is thought to prevent the host immune system from clearing infection, Streptococcus pyogenes, or group A Streptococcus, displays beta hemolysis. Some weakly beta-hemolytic species cause intense beta hemolysis when grown together with a strain of Staphylococcus and this is called the CAMP test. Clostridium perfringens can be identified presumptively with this test, Listeria monocytogenes is also positive on sheeps blood agar
9.
OCLC
–
The Online Computer Library Center is a US-based nonprofit cooperative organization dedicated to the public purposes of furthering access to the worlds information and reducing information costs. It was founded in 1967 as the Ohio College Library Center, OCLC and its member libraries cooperatively produce and maintain WorldCat, the largest online public access catalog in the world. OCLC is funded mainly by the fees that libraries have to pay for its services, the group first met on July 5,1967 on the campus of the Ohio State University to sign the articles of incorporation for the nonprofit organization. The group hired Frederick G. Kilgour, a former Yale University medical school librarian, Kilgour wished to merge the latest information storage and retrieval system of the time, the computer, with the oldest, the library. The goal of network and database was to bring libraries together to cooperatively keep track of the worlds information in order to best serve researchers and scholars. The first library to do online cataloging through OCLC was the Alden Library at Ohio University on August 26,1971 and this was the first occurrence of online cataloging by any library worldwide. Membership in OCLC is based on use of services and contribution of data, between 1967 and 1977, OCLC membership was limited to institutions in Ohio, but in 1978, a new governance structure was established that allowed institutions from other states to join. In 2002, the structure was again modified to accommodate participation from outside the United States. As OCLC expanded services in the United States outside of Ohio, it relied on establishing strategic partnerships with networks, organizations that provided training, support, by 2008, there were 15 independent United States regional service providers. OCLC networks played a key role in OCLC governance, with networks electing delegates to serve on OCLC Members Council, in early 2009, OCLC negotiated new contracts with the former networks and opened a centralized support center. OCLC provides bibliographic, abstract and full-text information to anyone, OCLC and its member libraries cooperatively produce and maintain WorldCat—the OCLC Online Union Catalog, the largest online public access catalog in the world. WorldCat has holding records from public and private libraries worldwide. org, in October 2005, the OCLC technical staff began a wiki project, WikiD, allowing readers to add commentary and structured-field information associated with any WorldCat record. The Online Computer Library Center acquired the trademark and copyrights associated with the Dewey Decimal Classification System when it bought Forest Press in 1988, a browser for books with their Dewey Decimal Classifications was available until July 2013, it was replaced by the Classify Service. S. The reference management service QuestionPoint provides libraries with tools to communicate with users and this around-the-clock reference service is provided by a cooperative of participating global libraries. OCLC has produced cards for members since 1971 with its shared online catalog. OCLC commercially sells software, e. g. CONTENTdm for managing digital collections, OCLC has been conducting research for the library community for more than 30 years. In accordance with its mission, OCLC makes its research outcomes known through various publications and these publications, including journal articles, reports, newsletters, and presentations, are available through the organizations website. The most recent publications are displayed first, and all archived resources, membership Reports – A number of significant reports on topics ranging from virtual reference in libraries to perceptions about library funding
10.
Staphylococcus
–
Staphylococcus is a genus of Gram-positive bacteria. Under the microscope, they appear round, and form in grape-like clusters, the Staphylococcus genus includes at least 40 species. Of these, nine have two subspecies, one has three subspecies, and one has four subspecies, most are harmless and reside normally on the skin and mucous membranes of humans and other organisms. Found worldwide, they are a component of soil microbial flora. Succinus As with all names in binomial nomenclature, Staphylococcus is capitalized when used alone or with a specific species. Also, the abbreviations Staph and S. when used with a species are correctly italicized and capitalized, however, Staphylococcus is not capitalized or italicized when used in adjectival forms, as in a staphylococcal infection, or as the informal plural. The S. saprophyticus and S. sciuri groups are generally novobiocin-resistant, members of the S. sciuri group are oxidase-positive due to their possession of the enzyme cytochrome c oxidase. This group is the only clade within the staphylococci to possess this gene, the S. sciuri group appears to be the closest relations to the genus Macrococcus. S. pulvereri has been shown to be a synonym of S. vitulinus. Within these clades, the S. haemolyticus and S. simulans groups appear to be related, as do the S. aureus, S. lugdunensis appears to be related to the S. haemolyticus group. S. petrasii may be related to S. haemolyticus, the taxonomic position of S. lyticans, S. pettenkoferi, S. petrasii, and S. pseudolugdunensis has yet to be clarified. The published descriptions of species do not appear to have been validly published. Staphylococcus species can be differentiated from other aerobic and facultative anaerobic, all species grow in the presence of bile salts. All species were thought to be coagulase-positive, but this has since been disproven. Growth can also occur in a 6. 5% NaCl solution, on Baird Parker medium, Staphylococcus species grow fermentatively, except for S. saprophyticus, which grows oxidatively. Staphylococcus species are resistant to bacitracin and susceptible to furazolidone, further biochemical testing is needed to identify to the species level. When these bacteria divide, they do so along two axes, so form clumps of bacteria and this is as opposed to streptococci, which divide along one axis, so form chains. One of the most important phenotypical features used in the classification of staphylococci is their ability to produce coagulase, six species are currently recognised as being coagulase-positive, S. aureus, S. delphini, S. hyicus, S. intermedius, S. lutrae, S
11.
Harrison's Principles of Internal Medicine
–
Harrisons Principles of Internal Medicine is an American textbook of internal medicine. First published in 1950, it is in its 19th edition, although it is aimed at all members of the medical profession, it is mainly used by internists and junior doctors in this field, as well as medical students. It is widely regarded as one of the most authoritative books on medicine and has been described as the most recognized book in all of medicine. The 18th edition of the book was edited by Anthony Fauci, Dennis Kasper, Stephen Hauser, J. Larry Jameson, new chapters added include Systems Biology in Health and Disease, The Human Microbiome, The Biology of Aging, and Neuropsychiatric Illnesses in War Veterans. The 19th edition of the book is edited by Dennis Kasper, Anthony Fauci, Stephen Hauser, Dan Longo, J. Larry Jameson and Joseph Loscalzo. Kasper DL, Braunwald E, Fauci AS, Hauser SL, Longo DL, Jameson JL, new York, McGraw-Hill Medical Publishing Division. Official website Harrisons Online, featuring the complete contents of Harrisons Principles of Internal Medicine, 18th Edition
12.
Fibrin
–
Fibrin is a fibrous, non-globular protein involved in the clotting of blood. It is formed by the action of the protease thrombin on fibrinogen which causes it to polymerize, the polymerized fibrin together with platelets forms a hemostatic plug or clot over a wound site. When the lining of a vessel is broken, platelets are attracted forming a platelet plug. These platelets have thrombin receptors on their surfaces that bind serum thrombin molecules which in turn convert soluble fibrinogen in the serum into fibrin at the wound site, Fibrin forms long strands of tough insoluble protein that are bound to the platelets. Factor XIII completes the cross-linking of fibrin so that it hardens, the cross-linked fibrin forms a mesh atop the platelet plug that completes the clot. Ineffective generation or premature lysis of fibrin increases the likelihood of a hemorrhage, dysfunction or disease of the liver can lead to a decrease in the production of fibrins inactive precursor, fibrinogen, or to the production of abnormal fibrinogen molecules with reduced activity. Hereditary abnormalities of fibrinogen are both quantitative and qualitative in nature and include afibrinogenaemia, hypofibrinogenaemia, dysfibrinogenaemia, and hypodysfibrinogenaemia, reduced, absent, or dysfunctional fibrin is likely to render patients as hemophiliacs. Fibrin from different animal sources is generally glycosylated with complex type biantennary asparagine linked glycans, variety is found in the degree of core fucosylation and in the type of sialic acid and galactose linkage. The image at the left is a structure of the double-d fragment from human fibrin with two bound ligands. The experimental method used to obtain the image was X-ray diffraction, the structure is mainly made up of single alpha helices shown in red and beta sheets shown in yellow. The two blue structures are the bound ligands, the chemical structures of the ligands are Ca2+ ion, alpha-D-mannose, and D-glucosamine. D-dimer Fibrin glue Fibrin scaffold Fibrinolysis TGW1916. net, Defibrinated blood harvested from sheep Fibrin, Molecule of the Month, by David Goodsell, RCSB Protein Data Bank
