Infarction enzymatic

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. 

Stone GW, Mehran R, Dangas G, et al. Differential impact on survival of electrocardiographic Q-wave versus enzymatic myocardial infarction after percutaneous intervention, A device-specific analysis of 7174 patients. Circulation 2001 ... 

During platelet plug formation, the fibrinolytic pathway is locally activated. Plasminogen is enzymatically processed to plasmin (fibri-nolysin) by plasminogen activators present in the tissue. Plasmin interferes in clot propagation and dissolves the fibrin network as wounds heal. At present, a number of fibrinolytic enzymes are available for treatment of myocardial infarctions or pulmonary emboli (see p. 201). 

Roberts R, Henry PD, Sobel BE. An improved basis for enzymatic estimation of infarct size. Circulation 1975 52 743-54. 

All these four aspects have their own prognostic implications, but also are complementary amongst themselves and with the clinical and enzymatic risk markers (age, history of infarction, risk factors and level of enzymes risk score) (Morrow etal, 2000a,b) (p. 257). We will now discuss these in detail. 

The presence of different ECG patterns plays a decisive role in the risk stratification of patients with NSTE-ACS. Table 8.1 shows the different ECG patterns found in STE-ACS and NSTE-ACS. We will just highlight here that in case of NSTE-ACS the prognosis is worse when the patient evolves towards a non-Q-wave infarction and even more so when it ends up as a Q-wave infarction. Factors, such as age, the presence of refractory angina and previous infarctions, ejection fraction, enzymatic level,... 

This occurs mainly in distal occlusions of a nondominant LCX or RCA and in the enzymatic infarction (necrosette). Sometimes an apparently normal or mildly abnormal ECG (positive and symmetrical T wavein Vl-V2)may be seen in patients at high risk. To take sequential recordings is mandatory to check the presence of ST-segment deviations. 

The importance of other factors additional to amount ofnecrosis has also been studied. In patients with first acute MI treated with PCI, LAD-related MI show for a similar amount of myocardial necrosis as determined by enzymatic infarct size, lower left-ventricular ejection fraction (LVEF) when compared to non-LAD-related MI. LVEF-measured 6-month post-MI showed a decrease, for every 1000 cumulative lactate dehydrogenase release, of 4.8% for LAD and 2.4% for non-LAD-related infarcts (p < 0.0001), and these results remain in the multivariate analysis (Elsman et al., 2006). 

The ESC/ACC (Alpert et al., 2000) consensus of the new definition of MI considers that an MI exists when enzymatic-level increase (troponins) is found in presence of anginal pain or its equivalent, even when no changes are found in the ECG (sub-ECG MI) (Wagner et al, 2000 Table 6.2). Therefore, more infarctions will be diagnosed than before. In our opinion, we should accept this new classification, though it implies some social, economic and... 

Elsman P, Van t Hof AW, de Boer MJ et al. Impact of infarct location on left ventricular ejection fraction after correction for enzymatic infarct size in acute myocardial infarction treated with primary coronary intervention. Am Heart J 2006 151 1239.e9-14. 

Anderson JL, Karagounis LA, Becker LC, Sorensen SG, Menlove RL. TIMI perfusion grade 3 but not grade 2 results in improved outcome after thrombolysis for myocardial infarction. Ventriculographic, enzymatic, and electrocardiographic evidence from the TEAM-3 Study. Circulation 1993 87 1829-1839. 

Thus, overall in the three trials that assessed the potential benefit of a strategy in which thrombolysis was combined with PCI in the treatment of acute STEMI, no evidence of clinical benefit attributable to prompt PCI following thrombolysis was apparent. By contrast, complications occurred at an increased frequency. None of the trials had been powered to assess an impact on mortality. However, the lack of improvement in left ventricular ejection fraction, enzymatic estimate of infarct size, or the incidence of reinfarction was deemed to be discouraging. Moreover, the lack of apparent benefit was associated with an increased risk of bleeding. 

LDH is used for diagnosis of heart infarction and hepatitis, since its level in serum is considerably elevated in both these diseases. Purified LDH is used in coupled optical tests for the assay of other enzymes, e.g. pyruvate kinase, enolase, transaminases, and for the enzymatic determination of many metabolites, such as ADP, ATP, L-lactate and pyruvate. 

P. is - prostaglandin that is produced by enzymatic transformation of prostaglandin endoperoxides and which dilates blood vessels. P. is chemically unstable in aqueous solutions, but the mono sodium-salt is stable as a solid and in solution. In addition, p. shows antimetastatic effects and has been used for patients with acute myocardial infarction. It has also been postulated that p. acts to stimulate platelet adenylate cyclase and to prevent the action of thrombi in phospholipid breakdown as well as platelet aggregation. In clinical practice, it is used for preventing the loss of platelets in cases wdiere the blood comes into extracorporal contact with artificial surfaces, i.e., in hemodialysis, cardiopulmonary bypass, and charcoal column perfusion for treatment of liver failure. 

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