[MICROBIAL COMPOSITION OF VARIOUS SURFACES OF SKIN DURING DEVELOP- MENT OF ATOPIC DERMATITIS BASED ON DATA FROM MALDI-TOF MASS-SPECTROMETRY IDENTIFICATION METHOD].

AIM: Study transformation of skin microflora during development of atopic dermatitis. MATERIALS AND METHODS: 45 patients with various forms of atopic dermatitis (AtD) were examined. Control group consisted of 26 healthy individuals. The strains were cultivated on elective nutrient media. Identification ofthe isolated strains was carried out by MALDI-TOF mass-spectrometry method. RESULTS: A low frequency of occurrence of taxon Staphylococcus epidermidis on face skin and high frequency of occurrence of Staphylococcus aureus on upper and lower limb skin was established for AtD patients compared with healthy individuals. The frequency of occurrence of proteolyti-cally active isolates of S. aureus in AtD patients was 3 times higher than in healthy carriers of this taxon. Taxons of microorganisms not inherent to healthy individuals such as Bacillus mycoides, Pseudomonas putida, Pseudomonas radiobacter were isolated on lower limb and neck skin of AtD patients. A high frequency of occurrence of Cryptococcus satoi, Candida albicans, Malassezia globosa fungi was noted. CONCLUSION: A decrease of barrier functions of skin during AtD facilitates contamination of patients' skin with rare bacterial taxons and fungi. One of the possible mechanisms of suppression of immune competent cell functions could be proteolytic enzymes of S. aureus.

[THROMBIN-MEDIATED EFFECTS OF BLOOD MICROPARTICLES ON FORMATION, STRUCTURE, AND STABILITY OF FIBRIN CLOTS].

The effects of blood microparticles (MPs) on the dynamics of fibrin polymerization, clot structure and susceptibility to fibrinolysis were studied. Kinetics of fibrin polymerization, fibrinolysis, thrombin generation in platelet-free, microparticle-depleted and microparticle-depleted plasma replenished with cephalin, from healthy donors were analyzed in parallel. MPs have profound effects on all stages of fibrin formation, decrease its turbidity. All parameters obtained in the absence of MPs were recovered after reconstitution of phospholipids. Thrombin generation rates were reduced in the absence of MPs. In the presence of MPs the fibrin networks had less poro us structures with thinner fibers, while clots formed in the absence of MPs had larger pores and were built of thicker fibers. Clots formed in the presence of MPs were significantly more resistant to fibrinolysis. Results show that normally circulating MPs can support the formation of stable clots at the sites of vascular injury.

[3-Hydroxy-1,5-diaryl-4-pivaloyl-2,5-dihydro-2-pyrrolones induce the mitotic exit failure and cell death in tumor cells in vitro].

Some compound refering to the 3-hydroxy-1,5-diaryl-4-pivaloyl-2,5-dihydro-2-pyrrolones have been found to cause an increase in the number of mitotic cells and their subsequent death in vitro. This increased in the number of mitotic cells was not associated with increased cellular proliferative activity and was likely due to mitotic exit failure. Of note, the effect was more pronounced in the tumor cells when compared to human fibroblasts. Further studies are needed to investigate the molecular mechanisms of action of the compounds belonging to the class of 3-hydroxy-1,5-diaryl-4-pivaloyl-2,5-dihydro-2-pyrrolones.

Effects of Staphylococcus aureus supernatants on human lymphocyte surface receptors.

The effects of Staphylococcus aureus proteolytic enzymes on surface receptors of human lymphocytes were studied. Proteolytic activity was detected in 35 supernatants of 45 S. aureus strains. aur and sspA genes were detected by PCR in 43 strains. Incubation of lymphocytes showed reduced expression of receptors labeled with anti-CD8, anti-CD4, and anti-CD16 antibodies and no changes in the receptors labeled with anti-CD3 and anti-CD19 antibodies in comparison with the control (incubation with sterile nutrient medium). S. aureus enzymes can trigger in vivo one of the mechanisms of early death of lymphocyte subpopulations expressing these receptors.

Lymph and blood cytokines in fever of different severity.

Experiments on rats showed that pyrogenal-induced fever is associated with elevation of IL-1ß, IL-6, and IL-10 content in the thoracic duct lymph and blood plasma, whereas low-grade fever induced by administration of Freund's complete adjuvant is associated with elevation of only IL-6 concentration. The increase in IL-1ß concentration during fever and IL-6 concentration in both processes was more pronounced in the central lymph than in blood plasma. Unchanged concentrations of IL-1ß and IL-10 in low-grade fever apparently reflect differences in the mechanisms of these pathological processes.

[Bacterial proteases and bacterial resistance against human innate immunity factors].

The molecular and cell-mediated mechanisms that are developed by certain opportunistic and pathogenic bacteria and were obtained over the course of evolution to preserve resistance against principal components of human body innate immunity are summarized.

Expression of P2X receptor subtypes on CD34+ cells and c-kit+ cells of human umbilical blood.

The presence of several subtypes of P2X receptors on early hemopoietic precursors (CD34+) from human umbilical blood was detected by flow cytometry. The expression of P2X receptors on umbilical blood lymphocytes was an order of magnitude higher than that on adult human blood cells. Our results attest to early involvement of P2X receptors in differentiation of human hemopoietic cells.

Cell microvesicles during experimental endotoxemia.

The dynamics of microvesicle formation in arterial blood in generalized Schwartzman phenomenon was studied. Successive (with 24-h interval) intravenous injections of endotoxin to rabbits in a dose of 1 mg/kg and 3 mg/kg caused an increase in the content of microvesicles in the blood, some of them containing ecto-5'-nucleotidase. Biphasic changes in arterial blood clotting time and erythrocyte hemolysis were observed.

Key role of mitochondria in apoptosis of lymphocytes.

Changes in the mitochondrial potential, expression of phosphatidylserine, parameters of direct and lateral light scattering, and DNA fragmentation during spontaneous and induced apoptosis in peripheral blood lymphocytes were studied by flow cytofluorometry. Dexamethasone and Ca2+ ionophore A23187 served as inductors of apoptosis. A decrease in the mitochondrial potential is an early sign of spontaneous and induced apoptosis. Phosphatidylserine expression on the outer plasma membrane occurred later and inversely depended on the mitochondrial potential. Our results indicate that the involvement of mitochondria in spontaneous and induced apoptosis accompanied by a decrease in the mitochondrial potential is an early and key event of programmed lymphocyte death. The decrease in the mitochondrial potential of lymphocytes induced degradation of their nuclei (DNA fragmentation) and promoted elimination of apoptotic cells (phosphatidylserine expression).