Myocardial infarction creatine phosphokinase

The hrefly Inciferin system is very sensitive and can be conpled to any enzymatic reaction that prodnces or nses ATP. For example, creatine phosphokinase can be determined by this method and hence be nsed in the diagnosis of myocardial infarction and mnscle disorders. The creatine phosphokinase converts AMP into ATP which then nndergoes the reaction with Inciferin as shown in Fignre 3.25. ATP pro-dnction is essential for every known life form and the firefly Inciferin system can be nsed to check for microbial life. Hence systems have been developed that use a portable luminescence workstation to monitor sanitation in food manufacturing and to check for sterile environments in technological workplaces. The system can also be applied in checking cell viability, for instance in cell cultures and to measure the toxic effects of chemicals on cells. 

The diagnosis of myocardial infarction is based on the patient s history, ECG changes and significant increases in myocardial enzymes. In particular there is a rise in cardiac creatine phosphokinase, reaching a peak 24 hours post infarction and an increase in troponin I and T, which are specific markers of myocardial injury when infarction has occurred. 

Adenosine triphosphate creatine A-phosphotransferase (EC 2.7.3.2), also creatine phosphokinase. Creatine kinase is found in muscle and is responsible for the formation of creatine phosphate from creatine and adenosine triphosphate creatine phosphate is a higher energy source for muscle contraction. Creatine kinase is elevated in all forms of muscular dystrophy. Creatine kinase is dimer and is present as isozymes (CK-1, BB CK-2, MB CK-3, MM) and Ck-mt (mitochondrial). Creatine kinase is also used to measure cardiac muscle damage in myocardial infarction. See Bais, R. and Edwards, J.B., Creatine kinase, CRC Crit. Rev. Clin. Lab. ScL 16, 291-355, 1982 McLeish, M.J. and Kenyon, G.L., Relating structure to mechanism in creatine kinase, Crit. Rev. Biochem. Mol. Biol 40, 1-20, 2005. 

Myocardial infarction occurs when the blood supply to the heart muscle is blocked for an extended time. If this lack of blood supply, called ischemia, is prolonged, the myocardium suffers irreversible cell damage and muscle death, or infarction. When this happens, the concentration of cardiac enzymes in the blood rises dramatically as the dead cells release their contents into the bloodstream. Although many enzymes are liberated, three are of prime importance. These three enzymes, creatine phosphokinase (CPK), lactate dehydrogenase (LDH), and aspartate aminotransferase/serum glutamate-oxaloacetate transaminase (AST/SGOT), show a characteristic sequential rise in blood serum level following myocardial infarction and then return to normal. This enzyme profile, shown in the ac-... 

Creatine phosphokinase (CK), one of the proteins measured to follow Ann Jeina s myocardial infarction (see Chapter 6) is present in cells as dimers (two subunits). The dimers may be homodimers (two identical subunits of either the M [muscle] isozyme or the B [brain] isozyme), or heterodimers (MB) The MB isozyme is produced only by the heart and readily released from injured cardiomyocytes into the blood (see Chapter 6). 

A single dose of methylprednisolone (30 mg/kg) to patients with myocardial infarction did not affect the creatine-phos-phokinase pattern. However, following repeated doses (every 6 hours for 48 hours) creatine-phosphokinase levels remained elevated beyond 72 hours after initiation of treatment (98 ). 

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