The dual regulation by glucagon of the adenylate cyclase system in the embryonic chick heart]

Taken in physiological concentrations, glucagon increases the activity of adenylate cyclase from the heart of 11-day chick embryos, i.e. at the earliest investigated stage. High glucagon concentrations inhibit the enzyme from cardiac membranes at all ontogenetic stages except mature chicks in which glucagon produces stimulating effect. Guanine nucleotides potentiate this effect up to the 16th day of incubation, this effect being absent at later periods. Reconstruction of adenylate cyclase system from the heart of 16-day embryos with N-proteins from mature liver tissue of chicks results in the recovery of potentiating effect. However, at later developmental stages, potentiation was absent even in the presence of N-proteins.     

The rapid differential diagnosis of bacterial and viral meningitis by using the lysozyme test]

The authors have modified the technique of the lysozyme test by adding polimixin M sulfate into the gel bacterial medium. Rapid diagnosis with the use of this test is based on different time of the appearance of the lysis areas: in bacterial meningitides the CSF lysozyme activity is detectable within 15-120 min, whereas in viral meningitides it manifests 40-50 min later or does not manifest at all. The results were found to depend on the time of the CSF collection: the earlier the CSF samples were obtained, the higher was the share of positive results.     

The etiological structure of acute bacterial meningitis in different regions]

In 1985-1989 the etiological structure of acute bacterial meningitides (ABM) in children was studied in 4 largest industrial cities in different regions of the European part of the former USSR, as well as in 2 industrial cities of western Siberia. Due to the common methodological approach used in all investigations, comparable data were obtained in all cities. These investigations revealed that meningococci caused 53.0-86.7% of all cases of ABM in children, which corresponded to moderately increased morbidity rate in meningococcal infection (3.9-11.0 cases per 100,000 of the population, mostly 5.0-7.0 cases) in these cities with its progressive decrease during 3-4 years of observation. The gradual change of meningococci from group A, prevailing in the '70s and early '80s, to group B and in some cases the appearance of group C meningococci, accompanied by a decrease in morbidity rate, were noted. In St. Petersburg the indices of ABM morbidity in children aged up to 5 years for 1987 and 1988, caused by Haemophilus influenzae (0.74 and 4.13) and pneumococci (3.23 and 4.86), could be calculated. A great number of ABM cases of unclear etiology (15.9-33.3%) suggests that the number of ABM cases caused by these two infective agents was underestimated.