PubMed Health⌕ Search

Biomedical subjects

V L Bykov

Publications and source records attributed to V L Bykov.

At least 19 recordsLinked to original sources
PubMed1996

[The tissue and cell defense mechanisms of the oral mucosa].

The modern concepts of tissue and cell defense mechanisms in oral mucosa are discussed. These mechanisms include (a) physical barriers (of epithelium and lamina propria), (b) non-specific antimicrobial humoral factors, (c) non-specific cellular defense mechanisms, (d) specific immune humoral and cell-mediated defense mechanisms, (c) saliva, containing both non-specific and specific antimicrobial factors. Special reference is given to antigen-presenting dendritic cells and various lymphocyte subpopulations both in epithelium and in lamina propria. The interaction of different cell and tissue defense mechanisms and their regional variations are briefly characterized.

Animals↗
PubMed1993

[Tissue of ultimobranchial origin in normal and pathologically altered thyroid gland].

Heterogeneity of the thyroid parenchyma and the sources of development of its main components are considered. The least studied are components originating from the ultimobranchial body to which "the second" system of the ultimobranchial follicles and solid epithelial cell nests belong. The data on the incidence, topography and age dynamics of these nests are presented. Their histochemical and immunocytochemical characteristics are given. Hypothesis on a possible role of solid cell nests as a source of various cell types in the thyroid as well as on their probable participation in the genesis of mixed thyroid tumours is discussed.

Animals↗
PubMed1992

[Histochemical study of lesions in superficial and visceral candidiasis].

Mycotic foci were studied histochemically on various experimental models of candidiasis. NAD-H, NADP-H-diaphorase, acid phosphatase and ATPase were revealed in the fungi, the activity of these enzymes depended on the state of the fungus. Diaphorase activity in the mucous membrane epithelium falls only if it is damaged by massive invasion of pseudo-mycelium. Inhibition of the enzyme activity in the visceral foci (kidney, liver, heart) occurs only in case of pronounced destruction and is not observed at the distance from the fungi. The results do not confirm the idea of fungal secretion of mycotoxins penetrating into the surrounding tissues and damaging them.

Acid Phosphatase↗
PubMed1991

[The effect of cytostatics and corticosteroids on the phagocytic and fungicidal activity of the neutrophilic granulocytes].

In vitro tests have revealed that cytostatic agents and corticosteroids, introduced in vivo, produce an inhibitory effect on the phagocytic activity of mouse neutrophil granulocytes and on their capacity for the destruction of Candida albicans blastospores. The action of the above-mentioned preparations may be an important pathogenetic factor which when introduced into the animals, contributes to the development of candidiasis.

Adrenal Cortex Hormones↗
PubMed1991

[Problems for discussion in the development of candidal granulomas in the liver].

Controversial aspects of the development of infectious, in particular mycotic granulomas in the liver of laboratory animals (mice and rats) are discussed. Liver is the organ which is frequently used as a model for studying mechanisms and dynamics of the granulomatous inflammation. A high reactivity of the liver macrophagal system is noted and its ready response by granuloma formation to the bacterial cells, their walls and wall polysaccharide complexes. The expedience of revision of the criteria adopted for granuloma identification is doubted.

Animals↗
PubMed1990

[The interaction of neutrophilic granulocytes with Candida albicans fungi in the formation of mycotic foci under conditions of immunodepression].

In the electron-microscopic study of the interaction of neutrophil granulocytes with the fungal species C. albicans in the process of the formation of mycotic foci in mice under the conditions of cyclophosphamide-induced immunosuppression, mouse leukocytes have been found to retain their capacity for migration to the focus of inflammation and for the phagocytosis of fungal cells. At the same time the fungicidal activity of leukocytes is decreased, which is manifested by the prevalence of viable fungal cells with the partially digested cell wall in the cytoplasm of leukocytes.

Animals↗
PubMed1990

[Pathogenesis and morphogenesis of candidiasis in immunosuppression].

In this review, the peculiarities of etiology, pathogenesis and morphogenesis of candidiasis in immunosuppression (IS) are discussed. It is noted that in mycotic complications of IS, along with C. albicans other less pathogenic Candida species play increasingly important etiological role. Sequential analysis of development and clinical course of candidiasis reveals that IS has profound effect on the different pathomorphogenetic stages, including fungal adherence to the epithelial surfaces, invasion in the host tissues, hematogenous dissemination and formation of secondary lesions, as well as on histo- and organ pathology, tissue and cellular responses to the pathogen.

Animals↗
PubMed1990

[The dynamics of the invasive growth of Candida albicans in the host's tissues].

Using experimental models of candidal vaginitis in leukopenic mice and of stomatitis in neonatal animals, who developed the minimal inflammatory response, the author has defined the rate of invasive growth of C. albicans in mucosal stratified epithelium. Pseudomycelium was found to invade the epithelium at an average rate of 2 microns per hour, penetrating the entire epithelial lining within 24-48 hrs. These data have been extrapolated to a clinical condition. On the basis of measurements of mucosal epithelium thickness (carried out with autopsy and biopsy material), presumable periods of the total epithelium penetration were calculated; such penetration results in vascular invasion, thus making possible a disseminated involvement. These periods ranged from 22 to 59 hrs for different mucous membranes. Our findings demonstrate the significance of cellular and tissue defense reactions, which, if suppressed, may induce the fungi, normally found on epithelial surface as saprophytes, invade the host tissues and cause deep (and in some cases disseminated) mycotic involvement within several days.

Animals↗
PubMed1990

[Candidal carriage and the development of invasive candidiasis of the organs of the digestive tract during experimental immunodepression].

After infecting healthy mice with Candida by their oral administration the fungi are rapidly eliminated from the digestive tract. In the animals, immunosuppressed by the injection of cyclophosphamide, the prolonged persistence of Candida in the digestive tract occurs, and the administration of Candida in considerable doses over prolonged periods in combination with the injections of high doses of immunosuppressing agents results in the development of profound invasive lesions, in some cases leading to the dissemination of the process.

Animals↗
PubMed1990

[Histological, histochemical and ultrastructural analyses of the development of candidal granulomas].

The development of Candida granulomas was studied in experimental model using histological, enzyme histochemical and electron microscopic methods. The granulomatous response first appeared 3-5 days after injection of heat-killed Candida albicans blastospores in hepatic portal system of mice. This response reached maximum at 10-12 days, when a significant part of hepatic parenchyma was involved, regressing thereafter. In the course of maturation, the granulomas, initially consisting of loose aggregates of monocytes and immature macrophages, were transformed into compact structures with the predominance of mature epithelioid cells with typical enzyme histochemical and fine structural features. In regressing granulomas, the accumulation of immature cells was again seen. Long-term administration of cyclophosphamide suppressed the development of Candida hepatic granulomas.

Animals↗
PubMed1990

[The morphogenesis of candidiasis of the mucous membranes after the administration of immunodepressants].

Influence of the immunosuppressants on the development and course of the experimental candidiasis was studied using the model of the murine vaginitis. As distinct from the mice with an intact immune system in which the fungi penetrate into the mucous membrane epithelium only superficially and are rapidly destroyed by the neutrophil granulocytes, the administration of immunosuppressants results in the penetration of the pseudomycelium through the epithelium and its invasion into the lamina propria, vessels and (in some cases) the development of the hematogenic dissemination. Tissue protective reactions are totally inhibited after the administration of high doses and partly depressed and inefficient after moderate doses of immunosuppressants.

Animals↗
PubMed1989

[Morphological analysis of the effect of corticosteroids on the development and course of vaginal candidiasis].

Specific features of the development and course of vaginal candidiasis were examined in corticosteroid-treated mice. Corticosteoids enhance epithelial adhesion of fungal cells and contribute to rapid invasion of the causative agent. Tissue inflammatory response in slow and weak. Pseudomycelium penetrates deep into Malpighi's layer, and, at some sites, damages the epithelial basal layer and invades the mucosal plate. In some animals, vascular invasion led to hematogenic dissemination. The described tissue and cellular mechanisms must be the basis of the stimulating effect of corticosteroids on vaginal candidiasis in the humans.

Adhesiveness↗
PubMed1989

[Histologic diagnosis of African histoplasmosis (the first case of the disease in the USSR)].

The findings obtained from histological examination of a biopsy specimen enabled a case of African histoplasmosis to be first recorded in the USSR. The disease was detected in an African student who had had a long-term latent period. The diagnosis was culturally and clinically verified. The problems of the histological differential diagnosis of African histoplasmosis are also discussed.

Adult↗