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DNA glycosylases are enzymes that initiate base excision repair, a process of removal of damaged bases from the cellular DNA. Recent data show that variants of two human DNA glycosylases, MUTYH and OGG1, are associated with an increased risk of cancer. In addition, activities of various DNA glycosylases have been implicated in protection of humans from neurodegenerative diseases, immune disorders and viral infections. On the other hand, DNA glycosylases from pathogenic microorganisms help them to avoid the host defensive systems. Thus, DNA glycosylases represent both potential therapeutic agents and drug targets.

The specific activity of serine, metal dependent and thiolic Ig proteases in the coprofiltrates of children with manifestations of intestinal dysbacteriosis was determined by the enzyme immunoassay. 56 children with pronounced symptoms of intestinal disorders (37 children aged up to 1 year and 19 children over 1 year) were examined. A group of 25 clinically healthy children was used as control. Simultaneously with protease activity of coprofiltrates, there was detected the level of Ig-degrading activity of the opportunistic bacteria islolates of different taxonomic groups from feces of children with dysbacteriosis of different severity (as determined by the classical bacteriological method). The evaluation of the Ig-proteolytic activity of fecal supernatants, associated with the presence of serine, metal-dependent and thiolic proteases in the intestine, as well as detection of such proteases in microbial isolates, seems to be highly important for the diagnosis of intestinal disorders in children and is recommended for screening of intestinal dysbacteriosis.

In the course of the study of the biochemical rapid method for the evaluation of microecological changes in the intestine by means of the test for the caseinolytic activity of fecal supernatants, the simultaneous presence of several enzymes in the samples under test was shown. Different degrees of the thermal inactivation of the active principle, linked with the expression of the positive caseinolytic sample, were established. The manifestations of caseinolytic activity, differing in their thermal stability, were found to have the proteolysis zone of equal size. The study showed the stability of this sign and its preservation during 1.5-2 years of storage of fecal supernatants in a refrigerator. Some details of making tests according to this method and the conditions ensuring the standard reproducibility of results were ascertained.

The persistent properties of the intestinal microflora as a mechanism of adaptation to the host's antimicrobial factors are substantiated. The results of determination of antilysozyme and anticomplementary activities and the inactivating abilities of the bactericidal component of interferon in enteric bacteria isolated in intestinal dysbacteriosis are outlined. Changes were found in the population structure of the Escherichia flora in relation to the severity of dysbacteriosis and a high prevalence of persistent signs were revealed in enteric bacteria. There was a correlation between the persistent signs of bacteria and the severity of intestinal microbiocenotic abnormalities. The factors of microbial persistence are proposed to be used as markers of a dysbiotic process.

A method of primary selection of immunomodulators based on measuring of ecto 5'-nucleotidase activity level of macrophages of peritoneal exudate was developed. Immunostimulators were found to decrease the activity level, while immunosuppressors increased the activity. The preparations having no immunomodulatory effect do not change the activity of this enzyme.

Clinical course of the burn disease of a severe, or extremely severe degree was studied in 56 children aging from 1 to 5 years. It was established that intensity of a leukocytic reaction and the redistribution reactions of neutrophil granulocytes with different activity of myeloperoxidase objectively reflected the course of a pathologic process, permitted to predict the development of local and general infective complications, and to make up a rational program for treatment with differentiated use of the methods of detoxication and immunotherapy. Activity of acid phosphatase and content of PAS-positive substances in neutrophil granulocytes didn't correlated with severity of the course of the burn disease.

Activity of enzymes involved in the bactericidal properties of neutrophils and their capacity to reduce nitroblue tetrazolium were studied in 60 patients with acute myeloblastic leukemia (AML). AML patients with infectious complications showed significantly higher values of enzyme activity than AML patients without such complications, although the values in the control group (patients without leukemia but with inflammatory conditions of the nasopharynx) were higher than in any of AML patients. The conclusion is drawn that the decrease of the bactericidal properties of neutrophils is linked with the disturbance of their oxidative metabolism thus resulting in frequent infections complications in patients with AML.