[MORPHOMETRIC AND HISTOCHEMICAL CHARACTERISTICS OF THE THYROID GLAND AFTER ADMINISTRATION OF HYDRA PEPTIDE MORPHOGEN].

The effect of Hydra peptide morphogen (HPM) on quantitative histochemical and morphometric parameters of the thyroid gland (TG) was studied. The experiments were conducted on 40 outbred albino male mice weighing 20-25 g, which were injected intraperitoneally with HPM at the dose of 100 µg/kg of body weight per day for 5 days. Relative volumes occupied by the epithelium (E), including its follicular (E(f)), interfollicular (E(i)) components, and colloid (C) were determined using stereological method on TG transverse sections. E(f)/E(i) and E/C ratios were calculated as the indices of follicular organization and TG activity, respectively. Mitotic activity of thyrocytes was also evaluated. The enzymes, characterizing the metabolic activity of thyrocytes: NADH-diaphorase, succinate- and lactate dehydrogenases were demonstrated on cryostat sections of material, frozen in liquid nitrogen and their activity was assessed cytophotometrically. The results demonstrated that HPM administration lead to a significant increase in relative volume of thyroid epithelium with a concomitant reduction of the volume of the colloid. E(f)/E(i) ratio was not significantly different from that in the control. HPM also induced a significant increase of thyrocyte proliferation rate and of the activity of enzymes studied. Collectively, the quantitative histoenzymological and morphometric data obtained indicate the stimulating effect of HPM on TG functional activity and thyrocyte proliferation.

[Paneth cells: history of discovery, structural and functional characteristics and the role in the maintenance of homeostasis in the small intestine].

Cells with acidophilic granules in the crypts of the small intestine were first described, along with the other cells of intestinal epithelium, in 1872 by a well-known German anatomist, histologist and anthropologist G.A. Schwalbe, however they were named after an Austrian histologist and physiologist J. Paneth, who has performed their detailed morphological analysis in 1888. For many decades the role of Paneth cells (PCs) remained completely unclear, until in 1960-1970 the production of antimicrobial molecules by these cells was found. At present, it is established that PCs produce a broad spectrum of antimicrobial compounds, thus controlling the number and content of intestinal microbial populations. PCs are an important part of innate immunity defense mechanisms, however, by interacting with the other cells, they participate in the reactions of the adaptive immunity. By creating high concentrations of antimicrobial substances within the crypt, PCs protect intestinal stem cells from the damage by potentially pathogenic microorganisms, while by releasing some signaling molecules, they control the vital functions of these cells, being an important component of their niche. Affecting the host tissues and influencing the microbial populations, PCs play a significant role in the maintenance of homeostasis in the intestine.

[Tissue and cell interactions in the oral mucosa after cytostatic drugs administration].

In the preceding work ("Morphology", 2011, issue 2), the regularities of oral mucosal (OM) epithelium injury after the cytostatic drug (CSD) treatment and its further regeneration, were reviewed. This paper presents the systematized summary of current literature data and the authors' own findings on the regularities of CSD effect on non-epithelial OM cell populations and their interactions with each other and the epithelium. The changes of intraepithelial tissue homeostasis, associated with CSD effect on intraepithelial lymphocytes, granulocytes, dendritic antigen presenting cells and melanocytes, interacting with epitheliocytes, are described. The data are presented, indicating that along with the epithelium, the cell populations of lamina propria and submucosal connective tissue, as well as the small blood vessels, are important targets of CSD in the OM tissues. The concept of a unifying model, describing tissue, cellular and molecular mechanisms of the oral mucositis development after CSD treatment, is reviewed.

[Injury and reparative regeneration of the oral mucosal epithelium after cytostatic drugs administration (tissue, cell and molecular mechanisms)].

This paper presents the systematized summary of current literature data and the authors' own findings on the regularities of human and animal surface oral mucosal epithelium (OME) injury caused by cytostatic drugs (CSD) administration, and on the ways of its regeneration after the cytostatic chemotherapy (CSCT) discontinuation. Tissue, cell and molecular mechanisms of CSCT effects on OME, are described. The direct effects of CSD included the epithelial layer attenuation with the derangement of its architecture, epitheliocyte proliferation suppression, apoptosis activation, and differentiation disturbances (involving the broad spectrum of cytological, cytochemical, ultrastructural and molecular-biological changes). In severe cases, these processes resulted in the loss of the epithelial layer integrity with the development of ulceration. Complete epithelial regeneration requires a long period after the CSCT discontinuation. Indirect effects of CSD on OME are associated with the microbial invasion and the diffusion of microbial vital activity products into the epithelium with concurrent leukopenia, immunosuppression and decreased salivary secretion.

[Morpho-functional characteristic of oral mucosal epithelium after treatment with a cytostatic drug].

The effect of cytostatic drug cyclophosphamide (CY) on lingual epithelium was studied in 90 female mice using histological, morphometric, quantitative histochemical and immunohistochemical methods. CY (400 mg/kg) was injected intraperitoneally three times with a 48 h interval. Material was obtained 2 days after injections and 10-20 days after their discontinuation. CY treatment was shown to result in the damage of both surface epithelium of the tongue and the epithelium of minor lingual salivary glands. Damage to the surface epithelium was more pronounced on the ventral surface of the tongue and was associated mainly with the disturbances of its proliferation. Changes were less severe on the dorsal surface and were seen as the disturbances of epithelial differentiation and desquamation. Glandular epithelium was damaged to a lesser extent than the surface one, with serocytes being more sensitive to the cytotoxic injury than mucocytes. After cytostatic drug discontinuation, the tendency for the normalization of the epithelial characteristics was noted. Most persistent changes in the surface epithelium were found on the dorsal surface of the tongue and in the glandular epithelium--in the serous secretory portions of the salivary glands.

[Tissue engineering of the oral mucosa].

This review contains the systematized data on the development and application of tissue engineering methods to generate in vitro oral mucosa (OM) tissues and its full-thickness equivalents. The data are presented describing the cultivation of epithelial monolayers and stratified sheets and connective tissue component, as well as their unification into the tissue-engineered constructs reproducing the structure of native OM. The equivalents engineered in vitro are used as the transplants in the areas of the defects of OM, or of some other mucous membranes and the skin. They are also widely applied as test-systems for in vitro experiments conducted to assess the effect of various factors on OM.

[Juxtaoral organ of Chievitz].

This review presents the analysis of the systematized data on human juxtaoral organ (JOO) development, structure and function based on the results of classical and recent morphological studies. JOO morphogenesis is traced, including the appearance of its anlage at the bottom of the primitive mouth, epithelial invagination into the mesenchyme, JOO detachment from the oral epithelium, its innervation, connective tissue capsule formation, and final maturation. The analysis of the results of macroscopical, histological, electron microscopical, histochemical and immunohistochemical studies is presented, suggesting high metabolic and synthetic activity of its epithelium, which expresses several neural markers, and emphasizing a rich innervation of both its epithelial and stromal components. The findings supporting the concepts of JOO secretory and mechanosensory functions, are examined. The data on the differential diagnosis between JOO and tumoral processes are discussed, as well as the pathological changes of JOO itself and their significance for the diagnosis of the diseases.

[Morpho-functional characteristics of the lingual epithelium after administration of hydra peptide morphogen].

Using histological, morphometric and quantitative histoenzymological methods, the changes of lingual epithelium were studied in 40 outbred albino mice after 5 intraperitoneal injections of 100 micrograms of hydra peptide morphogen (HPM) per 1 kg of body weight. Administration of HPM was found to increase the total thickness of epithelial layer on the dorsal tongue surface in the interpapillary regions, while in the area of filiform papillae these changes were not significant. On the ventral tongue surface HPM induced a marked increase of total thickness of the epithelial layer as compared to that in control animals. Mitotic activity was increased in the epithelium covering the ventral surface and in the interpapillary regions on the dorsal tongue surface. Histoenzymologic study which involved the demonstration of NADH-diaphorase, succinate- and lactate-dehydrogenase (LDH) activities, followed by a cytophotometric evaluation of enzyme activity, has shown a stimulatory effect of HPM on the activity of all the enzymes studied, which was most pronounced in respect to LDH and was maximally expressed on the dorsal tongue surface. These findings collectively suggest that HPM exerts a stimulatory effect on proliferation activity and metabolism of lingual epithelium, which is differentially expressed in its variuoe topographical zones.

[Functional morphology of the surface epithelium of esophageal tunica mucosa].

This review presents the systematized summary of classical and current conceptions on the functional morphology of the surface epithelium of esophageal tunica mucosa. The data describing the architecture of epithelial lining, classification and structure of its layers, are presented. The detailed characteristics of the cells of each layer and their ultrastructure, organization of germinal compartment, stem cell distribution and activity as related to their topography, are presented. The parameters of epitheliocyte cell cycle, mechanisms controlling their proliferation and circadian rhythms by growth factors and hormones, changes of proliferation activity under natural, pathological and experimental conditions, are discussed. The process of epithelial desquamation is described, as well as a mucus layer covering the epithelial surface together with its sources and protective role. The characteristics of the process of epitheliocyte apoptosis and the mechanisms of its control in normal and pathological states, are presented.

[Defense mechanisms of the surface epithelium of the human esophageal mucosa].

This review, which is based on the literature data and the results of personal research, contains an analysis of the current concepts on the tissue, cellular and molecular mechanisms, protecting human esophageal epithelium (EE) from gastric juice, bile, hot and rough food, microorganisms, alcohol, carcinogens, drugs and oxidizing agents. The response of EE to concrete environmental factors includes both specific and non-specific components, which depend on the nature of injurious agent. EE is damaged structurally and functionally only when it is exposed to the injurious factors of high intensity and/or long duration, which result in the exhaustion of resources of defense mechanisms. The insufficiency of EE defense mechanisms may be based on various genetic defects.

[Morphological and functional changes in the esophageal epithelium after treatment with a cytostatic agent].

Using histological, morphometric, histochemical and immunocytochemical methods, the effect of cytotoxic treatment on structural and functional characteristics of the epithelium of esophageal mucosa was studied in mice together with the reversibility of the changes induced by cytotoxic drug. Fourfold intraperitoneal injection of cyclophosphamide (400 mg/kg of body mass) resulted in such morpho-functional changes, as thickening of epithelial layer, increase in proportion of its stratum corneum and its loosening, disturbances in cornification process, hyperkeratosis, vacuolization of cell cytoplasm in stratum basale and stratum spinosum, interstitial edema, nuclear hypertrophy and parakeratosis. Mitotic activity and the activity of NADH-diaphorase were significantly reduced, while the number of PCNA' cells was increased. Cyclophosphamide had no significant affect on the concentration of total proteins. 15 days after the discontinuation of cytostatic treatment, most of the indexes did not return to normal values, indicating profound disturbances in the esophageal epithelium.

[Human gingival immunocompetent cells in the norm and in inflammatory periodontal diseases].

The review describes characteristics of gingival immuno-competent cells (lymphocytes, macrophages, dendritic antigen-presenting and plasma cells), forming a unified system and interacting with each other in physiological conditions and in inflammatory processes. The role of microbial factors and immunocompetent cell dysfunction in the development of destructive changes in periodontal tissues is analyzed. Gingival mast cell, fibroblast and epitheliocyte participation in immune reactions is discussed.