The heterogeneity of an influenza virus A population due to differences at individual hemagglutinin H3 sites]

Using monoclonal antibodies to hemagglutinin and nucleoprotein of various influenza virus strains, the populations of long-passaged strain A/Hong Kong/1/68 and of recently isolated strain A/sparrow/Ukraine/83 belonging to the H3N2 serovariant were shown to have subpopulations of virions differing in the structure of antigenic sites of hemagglutinin and in nucleoprotein domain which correlated with the degree of electrostatic interaction of virions with an ion-exchanger. The results of the study indicate a possibility of separation in the course of stepwise ion-exchange chromatography on DEAE-Sephadex A-50 of antigenic variants of influenza virus strains which is very important for the understanding of the mechanisms of population variability as well as for investigation of individual epitopes of hemagglutinin and nucleoprotein domains of influenza virus in evaluation of antigenic relationships of virions belonging to the same strain of a certain serotype.     

In vitro activity of ampicillin, cefoperazone, their combinations with sulbactam and other antimicrobials: survey of Russian isolates

Methodological differences makes it difficult to compare results of antimicrobial susceptibility testing obtained in Russia and in other regions. During the period from October 1993 to May 1994 susceptibility of 1296 isolates of bacteria was investigated according to NCCLS standards by the broth microdilution method. The order of activity of antibiotics against Gram-negative bacteria based on percent of susceptible strains from common hospitals were: amikacin (98%) > ciprofloxacin (93%) = imipenem (93%) > cefoperazone/sulbactam (92%) > ceftazidime (89%) > ceftriaxone (81%) > cefotaxime (80%) > cefoperazone (77%) > gentamicin (71%) > ampicillin/sulbactam (51%) > cefazoline (45%) > ampicillin (25%). The order of activity against strains from teaching hospitals was similar but the percent of susceptible strains was 10-20% less for the majority of antibiotics. The susceptibility level of Gram-negative isolates from Moscow teaching hospitals is lower than from Northern America and Europe. Ampicillln/sulbactam and cefoperazone/sulbactam, as well as other cephalosporins, demonstrated high activity against methicillin-susceptible staphylococci and penicillin-susceptible pneumococci. B-lactams/beta-lactamase inhibitor combinations were active against 100% strains of anaerobic bacteria.     

The no-reflow phenomenon and its clinical significance

The no-reflow phenomenon is characterized by inadequate myocardial perfusion without angiographic manifestations of mechanical vascular occlusion. The phenomenon occurs after coronary vascular interventions (coronary angiography, percutaneous coronary angioplasty, stenting, coronary artery bypass surgery). The development of the no-reflow phenomenon significantly worsens clinical evolution of disease increasing the number of cases of congestive heart failure and hospital mortality. Changes of endothelial function and morphology, changes of blood rheology and microvascular autoregulation are important for pathogenesis of the phenomenon. The treatment include intracoronary introduction of verapamil, adenosine, intravenous introduction of activators of KATP channels (nicorandil), inhibitors of glycoprotein IIb/IIIa receptors. The reasons for early preventive use of intracoronary introduction of verapamil and other drugs in the presence of risk of development of no-reflow phenomenon are presented. The interrelationship between no-reflow phenomenon and syndrome X is also stressed.     

Rheolytic thrombectomy with AngioJet catheter during transluminal coronary revascularization in patients with acute myocardial infarction

BACKGROUND: Although balloon angioplasty and stenting are effective in the treatment of acute myocardial infarction (M1), reduced coronary flow and distal embolization frequently complicate interventions when thrombus is present. Adjunctive treatment with mechanical thrombectomy devices was suggested to reduce these complications. METHODS: We evaluated immediate angiographic, in-hospital and 30-day follow-up clinical outcomes of 185 patients with acute MI and angiographically evident thrombus who were treated with AngioJet rheolytic thrombectomy followed by immediate definitive treatment. RESULTS: Procedural success (residual diameter stenosis <50% and thrombolysis in myocardial infarction [TIMI] flow >2 after final treatment) was 97%. Rheolytic thrombectomy success was achieved in 7% of patients. Subsequent definitive treatment included stenting in 67% and balloon angioplasty alone in 26% of patients. Final TIMI 3 flow was achieved in 89%. AngioJet treatment resulted in mean thrombus area reduction from 69.6 mm(2) at baseline to 17.3 mm(2) post-thrombectomy (p<0.001). Procedural complications included distal embolization (7.6%) and perforation (1.1%). Clinical success (procedure success without major in-hospital cardiac events) rate was 88%, in-hospital mortality - 7.0%. There were no further major adverse events during 30-day follow-up. CONCLUSION: Rheolytic thrombectomy can be performed safely and effectively in patients with acute MI, allowing for immediate definitive treatment of thrombus-containing lesions.     

The place of cardiac glycosides in the treatment of chronic heart failure. Part III. The DIG trial

In a series of papers the authors analyze literature data on the use of cardiac glycosides for long term treatment of chronic heart failure. Data obtained in prospective placebo controlled trial DIG show that digoxin significantly increases mortality of all patients with sinus rhythm and intact left ventricular systolic function (ejection fraction > 45%) and of women with left ventricular systolic dysfunction (ejection fraction < or = 45%). Men with left ventricular systolic dysfunction represent the only category of patients with chronic heart failure in sinus rhythm in whom long term administration of digoxin is justified. Digoxin does not affect mortality of these patients however it reduces requirements in hospitalizations due to worsening of heart failure.     

Comparison of the informative value of the dipyridamole test, transesophageal electrostimulation and exercise tests in the diagnosis of coronary heart disease]

The informative value of dipyridamole test, transesophageal cardiac pacing, bicycle ergometer and treadmill exercise tests were compared in 65 patients suspected for coronary heart disease and Functional Classes I-III angina pectoris. The sensitivity, specificity, positive and negative predictive values of the techniques alone and in various combinations were evaluated. The incoincidence of results from exercise tests was ascertained to be 40-48%. The significance of diagnosis increased with combined functional examination and reached the maximum when all the four tests were performed. The use of the sensitivity, specificity, and predictive value of the techniques in assessing the individual test results allows the optimal scope of studies to be determined on an individual basis in order to make or exclude the diagnosis of coronary heart disease.     

Aspirin in primary prevention of ischemic heart disease

High efficacy of aspirin in secondary prevention after myocardial infarction and stroke is well established. However the place of aspirin in primary prevention of coronary heart disease and other cardiovascular diseases remains questionable. Analysis of results of large controlled studies of efficacy and safety of aspirin in high risk subjects shows that low doses of aspirin should be used in men with high risk of coronary heart disease but without main risk factors of stroke.     

Long term use of a non-selective beta-blocker with vasodilating properties carvedilol in patients with severe heart failure

Results of drug treatment of 51 patients (41 men, 10 women) aged 35-86 years (mean age 62 years) included into COPERNICUS trial are presented. All patients had compensated NYHA class IV chronic heart failure and left ventricular ejection fraction less than 25%. For at least 2 months the patients received therapy with diuretics and angiotensin converting enzyme inhibitors (84%) or angiotensin receptor blockers (16%) and then were randomized to either carvedilol or placebo. Average duration of follow-up was 17 months. Carvedilol was well tolerated both during dose titration and during maintenance therapy. Addition of carvedilol to standard therapy of patients with severe heart failure was associated with increase of average ejection fraction from 21.7 to 30.3%. Rates of cardiovascular and sudden deaths, risk of hospitalization among carvedilol treated patients were 25, 33 and 57% less than among patients subjected only to standard therapy.