SUMMARY / RELATED TOPICS

Adenosine monophosphate

Adenosine monophosphate known as 5'-adenylic acid, is a nucleotide. AMP consists of a phosphate group, the sugar ribose, the nucleobase adenine; as a substituent it takes the form of the prefix adenylyl-. AMP plays an important role in many cellular metabolic processes, being interconverted to ADP and/or ATP. AMP is a component in the synthesis of RNA. AMP does not have the high energy phosphoanhydride bond associated with ADP and ATP. AMP can be produced from ADP: 2 ADP → ATP + AMPOr AMP may be produced by the hydrolysis of one high energy phosphate bond of ADP: ADP + H2O → AMP + PiAMP can be formed by hydrolysis of ATP into AMP and pyrophosphate: ATP + H2O → AMP + PPiWhen RNA is broken down by living systems, nucleoside monophosphates, including adenosine monophosphate, are formed. AMP can be regenerated to ATP as follows: AMP + ATP → 2 ADP ADP + Pi → ATP AMP can be converted into IMP by the enzyme myoadenylate deaminase, freeing an ammonia group. In a catabolic pathway, adenosine monophosphate can be converted to uric acid, excreted from the body in mammals.

The eukaryotic cell enzyme 5' adenosine monophosphate-activated protein kinase, or AMPK, utilizes AMP for homeostatic energy processes during times of high cellular energy expenditure, such as exercise. Since ATP cleavage, corresponding phosphorylation reactions, are utilized in various processes throughout the body as a source of energy, ATP production is necessary to further create energy for those mammalian cells. AMPK, as a cellular energy sensor, is activated by decreasing levels of ATP, accompanied by increasing levels of ADP and AMP. Though phosphorylation appears to be the main activator for AMPK, some studies suggest that AMP is an allosteric regulator as well as a direct agonist for AMPK. Furthermore, other studies suggest that the high ratio of AMP:ATP levels in cells, rather than just AMP, activate AMPK. For example, the species of Caenorhabditis elegans and Drosophila melanogaster and their AMP-activated kinases were found to have been activated by AMP, while species of yeast and plant kinases were not allosterically activated by AMP.

AMP binds to the γ-subunit of AMPK, leading to the activation of the kinase, eventually a cascade of other processes such as the activation of catabolic pathways and inhibition of anabolic pathways to regenerate ATP. Catabolic mechanisms, which generate ATP through the release of energy from breaking down molecules, are activated by the AMPK enzyme while anabolic mechanisms, which utilize energy from ATP to form products, are inhibited. Though the γ-subunit can bind AMP/ADP/ATP, only the binding of AMP/ADP results in a conformational shift of the enzyme protein; this variance in AMP/ADP versus ATP binding leads to a shift in the dephosphorylation state for the enzyme. The dephosphorylation of AMPK through various protein phosphatases inactivates catalytic function. AMP/ADP protects AMPK from being inactivated by binding to the γ-subunit and maintaining the dephosphorylation state. AMP can exist as a cyclic structure known as cyclic AMP. Within certain cells the enzyme adenylate cyclase makes cAMP from ATP, this reaction is regulated by hormones such as adrenaline or glucagon.

CAMP plays an important role in intracellular signaling. GMD MS Spectrum

Mycotic aneurysm

An infected aneurysm is an aneurysm arising from bacterial infection of the arterial wall. It can be a common complication of the hematogenous spread of bacterial infection. William Osler first used the term "mycotic aneurysm" in 1885 to describe a mushroom-shaped aneurysm in a patient with subacute bacterial endocarditis; this may create considerable confusion, since "mycotic" is used to define fungal infections. However, mycotic aneurysm is still used for all extracardiac or intracardiac aneurysms caused by infections, except for syphilitic aortitis; the term "infected aneurysm" proposed by Jarrett and associates is more appropriate, since few infections involve fungi. According to some authors, a more accurate term might have been endovascular infection or infective vasculitis, because mycotic aneurysms are not due to a fungal organism. Mycotic aneurysms account for 2.6% of aortic aneurysms. For the clinician, early diagnosis is the cornerstone of effective treatment. Without medical or surgical management, catastrophic hemorrhage or uncontrolled sepsis may occur.

However, symptomatology is nonspecific during the early stages, so a high index of suspicion is required to make the diagnosis. Intracranial mycotic aneurysms complicate about 2% to 3% of infective endocarditis cases, although as many as 15% to 29% of patients with IE have neurologic symptoms

Paul Penson

Paul Eugene Penson was an American professional baseball player. A right-handed pitcher from Kansas City, Kansas, he worked in five games in Major League Baseball for the Philadelphia Phillies in 1954, he was listed as 185 pounds. Penson's professional career began in April 1954 after he had had a successful three-year skein as a pitcher while he served in the military. Penson won 50 games pitching for his base team, although sources disagree about the branch in which he served, reported as the United States Air Force and the U. S. Army. Penson made the Phillies out of training camp in 1954 as a member of the team's early-season, 28-man roster, his five games pitched included three starts, he split two decisions. His lone MLB win came in his first start, on Sunday, May 16, 1954. in the second game of a doubleheader at Connie Mack Stadium. He went six innings against the St. Louis Cardinals, allowed four hits, four bases on balls, one earned run, but he was forced to leave the game leading 6–3 when the game was suspended because of Pennsylvania blue laws prohibiting sporting events on Sunday evenings.

The game resumed on Monday, May 17, Philadelphia went on to win, 8–4. Penson would allow eight earned runs on 14 hits and 14 bases on balls in his 16 career MLB innings pitched. Plagued by a sore arm, he disappeared into minor league baseball after May 30, where he won only three of 19 decisions before leaving the game in 1956. Career statistics and player information from Baseball-Reference