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Biomedical subjects

I S Petrova

Publications and source records attributed to I S Petrova.

At least 19 recordsLinked to original sources
PubMed1982

[Trypsin-like proteinase from Actinomyces fradiae 119].

Using electrophoresis and ultracentrifugation, a homogeneous proteinase was isolated from protofradine, a protease Act. fradiae 119 preparation. The purification procedure included filtration on DEAE-cellulose, gel filtration through Arcylex P-10, CM-chromatography and desalting on Sephadex G-15. The proteinase under study is an endopeptidase which hydrolyzes low molecular weight synthetic trypsin substrates as well as casein and denaturated collagen. Diisopropylfluorophosphate and soya bean trypsin inhibitor completely inhibit the proteinase activity, whereas pCMB and EDTA have no such effect. The stability maximum is observed at pH of 2.5-3.5, the action maximum at pH 8.7-9.5. The amino acid composition of the enzyme is similar to that of trypsin from Str. griseus. The molecular weights of the proteinase as determined by gel filtration and sedimentation equilibrium method are equal to 25400 and 26500, respectively. The isoelectric point lies at 5.3. The data obtained suggest that the proteinase can be attributed to the family of trypsin proteinases.

Actinomyces↗
PubMed1982

[Immunoepidemiological study of the meningococcal carrier state in groups of children and adolescents].

Immunoepidemiological study in groups of children of different ages was carried out. The study comprised the monthly bacteriological examination of the members of these groups and selective determination of the presence of specific meningococcal A- and C-antibodies, IgA, IgM and IgG in the blood serum, as well as the lysozyme activity of the saliva. The results thus obtained indicated that during the whole year two rises in the level of meningococcal carriership, in autumn and in spring, were registered, while the cases of meningococcal diseases were absent. The first rise was due to the influence of the conditions under which the groups had been formed, as well as to some decrease in specific immunity characteristics and nonspecific protective factors; the second rise occurred simultaneously with a considerable decrease in the content of specific meningococcal A- and O-antibodies.

Adolescent↗
PubMed1979

[Elastolytic enzymes from Actinomyces fradiae 119].

Using ion-exchange chromatography and gel-filtration, elastase II, the main elastolytic component of protofradin (preparation of proteases of Act. fradiae 119), was purified to an electrophoretically homogeneous state. The enzyme is a serine proteinase with mol. weight of 17800 +/- 1000 and a pI greater than 10. The enzyme is stable at pH greater than 4,0 and exhibits its maximal activity towards elastin at pH 9,2. An analysis of elastolytic products revealed that the enzyme hydrolyses natural elactin of bovine nuchal ligament to form large fragments with mol. weights ranging from 25 000 to 80 000 and small oligopeptides. The elastolysis is ceased at the stage of formation of short-chained peptides, predominantly tripeptides. Elastase I is a minor component of protofradin and in its molecular weight and some enzymatic properties is similar to elastase II.

Actinomyces↗
PubMed1979

[Immunological structure of the population vis-à-vis the meningococcus].

The immunological and epidemiological study of 3362 serum samples selectively taken from healthy persons in Yaroslavl showed the presence of highly pronounced inverse correlation between morbidity rate indices and level of antibodies, as well as direct correlation between the level of carriership and the level of antibodies, which indicated the specific character of this process. The analysis of serological data showed that all meningococcal antigenic fractions took part in the formation of the immunological structure of the population, but lipopolysaccharides and polysaccharides played the most active role in this process. The level of all immunoglobulin classes (especially IgA) in the sera of the persons selected for this study was also shown to depend on their age.

Adolescent↗
PubMed1978

[Evaluation of the sanative action of rifampicin on the meningococcal carrier state].

The results of the epidemiological control experiment on the efficacy of rifampicin in sanation of meningococci carriers are presented. The preliminary study of rifampicin sensitivity of 41 freshly isolated nasopharyngeal meningococcal strains showed that the MIC of the drug for 63 per cent of the isolates was 0.04--0.1 gamma/ml. Sanation was performed for 2 days; 1.2 g of the drug was used during the treatment course. The results of examination of 91 meningococci carriers showed that 4 days after the sanation the specific weight of the persons isolating no meningococci was reliably higher in the experimental group than that in the control group. The coefficient of rifampicin efficiency was 70.8 per cent. 10 days after sanation the difference in the level of the carriers isolating no meningococci in the experimental and the control groups was statistically insignificant. Therefore, the carriers treated with the drug received temporary protection from the causative agent at an average for 1 week. Later on they could become carriers again. As a result of sanation no changes in the meningococcal sensitivity to rifampicin was observed.

Adolescent↗
PubMed1976

[Isolation of individual proteases from protofradin].

An electrophoretically homogeneous trypsin-like proteinase, two homogeneous proteases (presumably metal-containing) and two elastases, possessing the ATEE-esterase activity, were isolated from protofradin, a protease preparation from Actinomyces fradiae 119, using fractionation on KM-cellulose K-32. The trypsin like proteinase of protofradin possesses the esterase activity, equal to the activity of pancreatic trypsin. Protofradin elastases differ in their pH optima, response to EDTA, stability upon storage and the degree of elastin hydrolysis. The specificity of elastase is probably the same, since in elastin both enzymes hydrolyze the peptide bonds, formed by the NH2-group of glycine and alanine residues, found in elastin in large amounts. The end products of elastin hydrolysis are tripeptides.

Actinomyces↗