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Biomedical subjects

V F Ivanova

Publications and source records attributed to V F Ivanova.

At least 19 recordsLinked to original sources
PubMed2006

[Structure-functional changes in the rat pancreas after glucose injection].

Electron microscopic method was used to study the effect of hyperglycemia on the pancreas of albino rats (n = 20) after intraperitoneal administration of 40% glucose solution (daily, for 5 days). The data obtained suggest that repeated administration of glucose was accompanied by marked changes in the structure B-endocrinocytes, indicative of the increased secretion of the insulin. This resulted in the appearance of new small pancreatic islets, that consisted of B-endocrinocytes and acino-insular cells. Most frequently acinar-insular cells were located at the periphery of newly formed islets. The latter often had a symplast-type structural organization.

Animals↗
PubMed2003

[Differentiation of human pancreatic endocrine cells in the period of fetal development].

The stereological analysis of electron micrographs of pancreatic endocrine cells (A and B) obtained from human fetuses at gestational months 4 to 7 was performed to assess the volume densities of membranous organelles (mitochondria, rough endoplasmic reticulum, Golgi complex), polysomes and secretory granules. The differences were established in the ratios of the volume densities of organelles and secretory granules in the process of differentiation. The morphometric characteristics of total A- and B-cell populations as well as the quantitative data on the structural organization of endocrine cells at various stages of differentiation are presented.

Cell Differentiation↗
PubMed2003

[Regularities of cytogenesis in the endocrine gastroenteropancreatic system in vertebrates].

This paper reviews the literature data and the results of authors' own investigations on cytogenesis of endocrine cells of gastro-entero-pancreatic (GEP-) system in vertebrate animals and man. In pancreas two groups of sources of endocrine cell development were distinguished including both intra- and extrainsular. In cytogenesis of mucosal endocrine cells in gastrointestinal tract (GIT) the major role belongs to the stem cells which differentiate through the stage of committed precursors ("agranular cells"). Pancreas and GIT epithelium are characterized by the formation of endocrine cells from exocrine ones. The data presented provide the indication of the endodermal origin of endocrine cells of GEP-system.

Animals↗
PubMed2001

[Cellular level of the body adaptation to the environmental exposure in the large industrial city (Saint-Petersburg)].

By methods of light and electron microscopy structural disturbances of heart, kidneys, liver and pancreas were studied in rats pups who were born and kept for a year at kindergartens of city districts diverse in level of environmental pollution (air and soil). The content of micronuclei in epitheliocytes of oral mucosa in 5-6 ys old children from the kindergartens was controlled in order to detect chromosome aberrations. The examination of morphofunctional state of the organs studied and cells containing micronuclei carried out in different districts of the city allowed to reveal correlation between disorders studied and the level of environmental pollution.

Adaptation, Physiological↗
PubMed2000

[The structure of the optic nerve in experimental glaucoma and in the means for its treatment].

Using light and electron microscopy disorders of structure of the optic nerve were studied in rabbits with adrenaline induced glaucoma and after the action of antioxidants (Emoxipine, Erisode) used for preventive and medical purposes. Changes in glaucoma and after administration of drugs in axons and their myelinated sheath were similar but differently pronounced in right and left eye of the same animal. Positive effect of Erisode used for preventive and medical purposes was noted. Emoxipine enhanced the disturbances in optic nerve structure.

Animals↗
PubMed1999

[Differentiation and cytogenesis of endocrine elements of the rat duodenum in ontogenesis].

Duodenal endocrine apparatus was studied in rat during individual development using electron microscopy. Endocrinocyte differentiation was demonstrated to occur in embryonic period and it is characterised by fast cytotype number growth. During embryogenesis processes of endocrinocyte differentiation occur more intensely than in adult animals which is manifested by higher incidence of different types of incretory elements in embryos. By the moment of birth EC-, L-, S-, D-, D1-, P and I-cells can be identified in the duodenal epithelium at different stages of differentiation as well as "mixed" exo-endocrine cells. The presence of transitory cellular forms from agranular elements up to mature differentiated endocrinocytes and "mixed" exo-endocrine cells reflects cytogenetic processes in population of endocrine cells and allows to consider duodenal epithelium both structurally and functionally as a tissue with common histogenetic basis.

APUD Cells↗
PubMed1998

[Endocrine apparatus of the epithelium of the appendicular mucosa (the appendix-- an endocrine gland, functioning in the embryonal period?].

Based on the concept on gastroenteropancreatic system, endocrinocytes of which are diffusely scattered throughout the digestive tract epithelium and are found in pancreatic islets, an analysis of endocrine apparatus of epithelium in human appendicular mucosa was performed at different stages of ontogenesis. The response of appendicular endocrinocytes to clinical pathology of both this organ and the entire organism was studied. On the base of the analysis of the appendix function from morphological view, the authors proposed a hypothesis postulating it to be an organ equal to an actively functioning endocrine gland and its unique role on early stages of embryogenesis.

Appendix↗
PubMed1997

[The endocrine apparatus of the epithelium of the gastric mucosa in the steppe turtle (Testudo horsfieldi)].

Endocrinocytes of stomach mucosal epithelium were studied using light and electron microscopy in steppe turtle (Testudo horsfieldi). Endocrine apparatus of stomach in turtle was shown to retain the pattern characteristic for other representatives of vertebrates. Difference is observed in endocrinocytes localization. The latter are accumulated predominantly in upper and middle regions of glandulae, sometimes being encountered also in surface epithelium. 8 cell types were identified according to size and structure: EC, G, D, D1, A-like, X, ECL and P. Relating to glandular lumen, endocrinocytes are divided into elements of closed (D, D1, A-like, ECL, X, and P) and open types (EC, G). In the latter apico-basal differentiation is expressed in cytoplasmic structure. Endocrinocytes are unevenly distributed throughout the stomach regions. Greatest number is concentrated in pyloric part, EC-cells being the predominant type. EC, ECL-cells and less A-like and D-cells are mostly encountered in fundal part, EC, G and single D and P cells--in pyloric part and, agranular and exo-endocrine cells--in both stomach parts.

Animals↗
PubMed1997

[Body adaptation to the action of ecological factors at the cellular and subcellular levels].

Chemical and physical factors action on different organ tissues in animals were examined by light and electron microscopy. Comparison of the action of the agents mentioned showed, that in both cases the totality of compensatory-adaptive reactions depends on heterochronism of the changes that develop in organelles, cells and tissues and is determined by individual sensitivity of animals and asynchronism of the development of primary reactions at the organelle level, which accounts for mosaic pattern of structure of cells, comprising the tissues. It is established that in cells energy metabolism is disturbed first due to mitochondria damage irrespective of the unfavourable factor. The phenomenon of tissue adaptation is considered as an integrative process that occur within the ontogenesis. The entire process of tissue adaptation at the level of cells and organelles is divided on 5 stages according to structural changes demonstrated while exerting the influence. This allows to estimate both direction and significance of the damage and tissue compensatory and reparative capacity.

Adaptation, Physiological↗
PubMed1996

[The morphofunctional status of the synovial membrane of the temporomandibular joint under exposure to a helium-neon laser].

By means of light and electronic microscopy the state of tissues of the temporomandibular joint synovial coat was examined in dogs. As a results a model of aseptic inflammation of temporomandibular joint was created (the first series of experiments), the impact of different dozes of helioneonic laser on intact tissues was studied and the most efficient doze of irradiation was established (the second series of experiments). On the third series it was shown that the doze of irradiation chosen influences positively the structural changes in synovial coat, caused by the aseptic inflammation.

Animals↗
PubMed1992

[Biologically active substances from the skin that influence the proliferation and differentiation of cultured human keratinocytes].

Three fractions of biologically active substances of human skin varying in molecular weight (F1 > 15 kD, F2 1.4-15 kD, F3 < 1.4 kD) were tested in primary and regenerating cultures of human epidermal keratinocytes. F1 and F3 caused stimulation of keratinocyte proliferation, F2 inhibited proliferation and enhanced terminal differentiation of epidermal cells.

Cell Differentiation↗
PubMed1990

Cholesterol accumulation in plasma membrane and changes of membrane enzyme activity of Acholeplasma laidlawii cells during culture ageing.

The data presented in this report show that the microviscosity of the plasma membrane and the cholesterol/phospholipid molar ratio of its lipid bilayer increases during ageing of Acholeplasma laidawii cultures. At the same time the age changes of other lipid components content do not correlate with the change of membrane viscosity. It is also shown that membrane enzyme activities of mycoplasma cell decrease with age. These results confirm the membrane hypothesis of ageing according to which increased microviscosity is the essential factor of cell ageing.

Acholeplasma laidlawii↗
PubMed1990

[Structure and cytophysiology of gastric endocrine gland cells after repeated administration of testosterone propionate].

By means of light, electron microscopy and morphometry methods contents and structural organization of endocrinocytes have been investigated in gastric glands of rats, to whom testosterone propionate has been injected for 5, 10, 15, 20 days. The hormone produces certain stimulating effect on the endocrine apparatus function. During the first stages of the experiment most of the endocrinocytes are at the state of active secretion; this is testified as a decreasing composition of histochemically revealed cells in epithelium and their degranulation. During the following stages the process of synthesis is activated in the cells and their amount increases. Appearance of numerous agranular, poorly differentiated endocrinocytes and exo-endocrine cells demonstrates certain intensification of cytogenesis of endocrinocytes in the gastric epithelium. The changes observed are considered as adaptive, directed to stabilize homeostasis, when the hormonal balance is disturbed.

Animals↗
PubMed1987

[Seasonal changes in the endocrine cells of the gastric epithelium of Rana temporaria].

By means of the light and electron microscopy methods histotopography, quantity and ultramicroscopic organization of endocrine cells (EC) have been studied in gastric epithelium of the frog (Rana temporaria) during various periods of its life: hibernation, awakening, active life. At all the periods of life 8 types of EC are revealed. Depending on the season, certain changes both in their amount and ultrastructural organization are observed. Decreasing amount of EC is noted during hibernation and their increase in spring during awakening and in summer. Quantity of enterochromaffin cells is not subjected to seasonal fluctuations. This is explained by the fact that in hibernation these cells are also at their active functional state, since they produce serotonin necessary for maintaining deep hypothermia, specific for hibernating animals.

APUD Cells↗
PubMed1987

[Endocrine cells in the large intestine epithelium in various vertebrate species].

Amount of argyrophile and argentoffin endocrine cells per 1 mm2 of the large intestine mucous membrane has been counted in the turtle, pigeon, white rat and frog at various periods of their life (winter hibernation, awakening, active life). As the animal's organization becomes more complicated, the amount of the endocrine cells in the epithelium increases both in the initial and in the terminal parts of the large intestine, their amount in the terminal (rectum) part being less than in the initial one. The greatest amount of the endocrine cells is found in simmer frogs at the expense of increasing content of the elements that do not belong to the argentaffin group. The latter do not significantly change during various seasons.

Animals↗
PubMed1987

[Endocrine apparatus of the duodenal epithelium in chronic gastroduodenitis in children].

Ultrastructural organization of the endocrine apparatus of the duodenum in children suffering from chronic gastroduodenitis was studied on 15 biopsies, and its involvement in pathological process is shown. Signs of the functional activity enhancement on the one hand and those of damage on the other hand are observed in the cells. Apart from that, poorly differentiated endocrine cells and "mixed" endocrine and exo-endocrine cells which can be considered as a manifestation of endocrine elements recovery appear in the duodenal epithelium.

Adolescent↗