ABSTRACT
Acute coronary syndromes range in severity from unstable angina to evolving myocardial infarction with persistent ST-segment elevation, with or without cardiogenic shock. Despite major improvements in medical and percutaneous therapy, acute coronary syndromes still represent a major cause of morbidity and mortality. The aggressive approaches to myocardial revascularization and mechanical circulatory support reviewed in this article seem to reduce the mortality associated with acute coronary syndromes. The optimal timing of surgery should not only reduce short-term mortality but also improve long-term outcomes.
Subject(s)
Acute Coronary Syndrome/therapy , Angioplasty, Balloon, Coronary , Assisted Circulation , Coronary Artery Bypass , Myocardial Infarction/therapy , Acute Coronary Syndrome/complications , Acute Coronary Syndrome/mortality , Acute Coronary Syndrome/surgery , Angina, Unstable/etiology , Angina, Unstable/therapy , Angioplasty, Balloon, Coronary/adverse effects , Angioplasty, Balloon, Coronary/mortality , Assisted Circulation/adverse effects , Assisted Circulation/mortality , Coronary Artery Bypass/adverse effects , Coronary Artery Bypass/mortality , Evidence-Based Medicine , Humans , Myocardial Infarction/etiology , Myocardial Infarction/mortality , Myocardial Infarction/surgery , Severity of Illness Index , Time Factors , Treatment OutcomeABSTRACT
5-Hydroxy-4-oxonorvaline (HON) was produced optimally by Streptomyces akiyoshiensis in media containing starch and casein supplemented with high concentrations of phosphate and magnesium sulfate; cultures grown at initial pH values between 6.3 and 6.6 yielded HON titres of 13-14 mM. Physiological analysis of HON production provided evidence that the excess inorganic constituents in this medium played an important role in optimizing production. In simple defined media buffered at pH 5.5-6.0 and inoculated with either a spore suspension or washed vegetative mycelium, formation of HON was less than one-third the amount produced in the starch-casein-salts medium. Production was markedly affected by the carbon and nitrogen sources used; media containing starch and potassium nitrate or aspartate supported the highest yields of HON. In starch-nitrate media, production was suppressed by excess nitrogen source, and the HON titre decreased 3-fold as the phosphate content was increased from 0.5 to 5 mM; growth was not appreciably altered. The results suggest that the high level of HON production in the complex starch-casein-salts medium is associated with sequestration of metabolic ammonium and reduced availability of phosphate through formation of the poorly soluble magnesium ammonium phosphate.