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Biomedical subjects

E A Smirnova

Publications and source records attributed to E A Smirnova.

At least 19 recordsLinked to original sources
PubMed2005

Natural conditions inducing programmed cell death in the yeast Saccharomyces cerevisiae.

Although yeasts have been extensively used as an experimental model to study apoptosis, it is still unclear why a unicellular organism like yeast possesses a suicide program. Here we discuss three hypothetical scenarios of "natural" yeast suicide. We argue that by correctly deducing the physiological situation(s) for yeast to undergo cell death, one can not only improve the efficiency of yeast as model system for apoptotic studies, but also obtain a certain insight into the survival strategies of communities of organisms.

Apoptosis↗
PubMed2005

[Chromosomal aberrations in myelodysplastic syndrome].

AIM: To analyse incidence rate of chromosomal aberrations in myelodysplastic syndromes (MDS), specification of clinicomorphological features of some cytogenetic variants. MATERIAL AND METHODS: Chromosomal analysis by the method of G-differential staining of chromosomes was made in 209 patients with different variants of MDS. RESULTS; Clonal chromosomal aberrations occured in 60.8%. The following aberrations were found most frequently: deletion of the long arm of the chromosome 5 (del(5q)) - 34.6%, trisomy of chromosome 8 (14.1%), monosomy of chromosome 7 (13.4%), aberrations 3q21q26 (12.6%), aberrations of a long arm of X-chromosome (4.7%), the absence of Y-chromosome (3.1%). Complex aberrations of karyotype were found in 13.5% cases. Chromosomal aberrations determined not only clinical and morphological features but also the prognosis of the disease. CONCLUSION: Cytogenetic examination is an essential component of MDS patients examination. It allows more precise classification of MDS variant and prognostification of the disease course.

Adolescent↗
PubMed2004

Expression of argyrophilic proteins in the nucleolar organizer regions of human thymocytes and thymic epitheliocytes under conditions of coculturing with vilon and epithalon peptides.

Vilon stimulated and Epithalon suppressed the expression of argyrophilic proteins in nucleolar organizer regions of thymocytes and epithelial cells, stimulating or reducing, respectively, the formation, assembly, and transport of ribosomes into the cytoplasm and thus determining the intensity of protein synthesis in these cells. A direct mitogenic effect of Vilon was also revealed: this peptide promoted thymocyte transformation into proliferating blast cells.

Cells, Cultured↗
PubMed2003

Effects of cholecystokinin-4 on secretory activity of rat mast cells.

Intraperitoneal injection of cholecystokinin-4 in a dose of 100 mg/kg markedly increased secretory activity of mast cells in the mesentery and subcutaneous fat. These changes developed 5 min after treatment and progressed in time. Over the first 15 min we observed primarily merocrine secretion (granulolysis), while 60 min after cholecystokinin-4 administration apocrine secretion (degranulation) prevailed. In vitro cholecystokinin-4 had no effect on secretory activity of mast cells. Our findings suggest that stimulation of secretory activity of mast cells is determined by psychoemotional stress associated with activation of the sympathoadrenal and hypothalamic-pituitary-adrenal systems.

Animals↗
PubMed2003

Secretory activity of mast cell during stress: effect of prolyl-glycyl-proline and Semax.

Stress increased secretory activity of mast cells in the mesentery and subcutaneous fat of rats. Intraperitoneal injection of Semax and prolyl-glycyl-proline in doses of 0.05 and 1 mg/kg, respectively, 1 h before stress abolished this effect. The test preparations did not modulate secretory activity of mast cells in unstressed animals. Semax and prolyl-glycyl-proline in vitro prevented activation of mast cells with synacten and acetylcholine. The stabilizing effect of peptides on mast cells probably determines their antiulcer activity.

Acetylcholine↗
PubMed2003

Glyprolines and semax prevent stress-induced microcirculatory disturbances in the mesentery.

One-hour immobilization stress considerably disturbed microcirculation in the mesentery: blood flow in small mesenteric vessels decreased or stopped and numerous hemorrhages appeared. Lymphatic vessels lost spontaneous activity and did not respond to norepinephrine. Administration of Semax and glyprolines 1 h before stress decreased the severity of stress-induced microcirculatory disturbances. PGP and GP were most effective in this respect.

Adrenocorticotropic Hormone↗
PubMed2003

[Ultrastructural criteria of clinical prognosis in hormonally non-active adrenocortical tumors].

The investigation was concerned with histological and ultrastructural features of adrenocortical tumors of the adrenals, which have a differential-diagnostic and clinico-prognostic relevance. Histological and electron-microscopical examination of 60 tumors (adrenocortical adenoma--12; adrenocortical cancer--48) was carried out and the findings were compared with clinical data. No significant correlation between histological pattern of adrenocortical tumors and survival was established. Ultrastructural evidence showed electron-microscopical examination to be a reliable procedure for making prognosis of adrenocortical cancers. There was a direct correlation between the level of differentiated cells and degree of their differentiation, on the one hand, and the quality of prognosis and survival, on the other. The significant predominance of differentiated cells was characteristic of adrenocortical adenomas.

Adrenal Cortex Neoplasms↗
PubMed2003

[Cell differentiation in human melanoma cells caused by dicarbamine (ultrastructural investigation)].

The effects of dicarbamine (r) and polytransretinoic acid (PTRA) on human melanoma MEL-6 transplanted into Balb/c nude female mice have been compared by histological and electron microscopic procedures. It was discovered that long-term administration of 1.5 mg/kg dicarbamine caused melanoma MEL-6 cells to undergo terminal differentiation. As a result, the number of melanosome-containing cells was 3-4 times and the number of melanosomes in them--5 times those in intact controls. Dicarbamine effect was double that of PTRA.

Animals↗
PubMed2003

[N-nitrosodiethylamine-induced changes in the liver of syrian hamster with superinvasive opistorchiasis].

Trematoda O. felinius-induced hepatic lesions were investigated in Syrian golden hamsters with superinvasive opistorchiasis. One hundred hamsters were divided into 4 groups: (1)--control; (2) N-nitrosodiethylamine (DENA), i.p., twice a week, 3 weeks, total dose 72 mg/kg; (3) metacercariae O. felinius, with drinking water, 3 injections per day, once in 2 weeks, and (4) metacercariae O. felinius, as in group 3, followed by DENA, as in group 2. Animals were sacrificed 12 months after the beginning of the study. No changes in the liver were found in group 2. Reddish protrusions, up to 4 cm in diameter, appeared on liver surfaces in groups 3 and 4. Group 4 featured the highest relative and absolute weights of liver as well as clusters of oval cells and cholangiocellular tubules and cholangiofibrosis (in group 3, they were less visible). Electron microscopic examination identified hepatocytes with destructive changes to plasmalemma, nucleus and cytoplasmic organelles. Also, perisinusoidal cells (Ito cells) occurred. Tumor-bearing animals showed low hepatic cytochrome P-450. It is suggested that proliferative growth in the liver was stimulated by opistorchis invasion.

Animals↗
PubMed2002

Defect-induced magnetic structure in (Ga(1)-(x)Mn(x))As.

We show that magnetic structures involving partial disorder of local magnetic moments on the Mn atoms in (Ga(1)-(x)Mn(x))As lower the total energy, compared to the case of perfect ferromagnetic ordering, when As defects on the Ga sublattice are present. Such magnetic structures are found to be stable for a range of concentrations of As antisites, and this result accounts for the observed magnetic moments and critical temperatures in (Ga(1)-(x)Mn(x))As. We propose an explanation for the stabilization of the partially disordered magnetic structures and conclude that the magnetization and critical temperatures should increase substantially by reducing the number of As antisite defects.

Journal Article↗
PubMed2002

Ultrastructural criteria of malignancy of adrenal medullary tumor.

Histological analysis and electron microscopy of 12 benign pheochromocytomas and 9 malignant pheochromoblastomas showed that there are no reliable histological differences between cells of benign and malignant tumor of the adrenal medulla. The ratio of ultrastructurally differentiated and undifferentiated cells in the tumor can reflect their maturity; the more ultrastructurally undifferentiated and less differentiated cells in the tumor, the higher is the malignant potential of this tumor.

Adrenal Gland Neoplasms↗
PubMed2002

[Disruption of organization of mitotic microtubules in root meristem cells of Allium cepa induced by chloral hydrate].

Data are presented on the effect of chlorahydrate on microtubule organization in the root meristem of Allium cepa. Our studies show that an incomplete preprophase band commonly appears during G2-prophase transition, yet the major effect is the lack of perinuclear microtubules, leading to inhibition of the prophase spindle formation and transition to C-mitosis. Upon chloralhydrate treatment of metaphase cells, we found cells with chromosomes regularly aligned within the metaphase plate and differently disorganized mitotic spindles. Concurrently, C-metaphase cells with remnants of kinetochore fibers were present. In addition, normal bipolar and abnormal irregular types of chromosome segregation were detected, this representing multipolar and diffuse anaphases. The major difference between them is the presence of polar microtubules during multipolar anaphase, and their lacking during diffuse anaphase. Alternatively, microtubule clusters between segregated groups of chromosomes are typical for cells with diffuse anaphase. During bipolar anaphase, excessive aster-like microtubules emanate from the spindle poles, and in telophase accessory phragmoplasts are observed at the cell periphery. The formation of incomplete phragmoplasts was observed after normal bipolar and abnormal chromosome segregation. We conclude that chloralhydrate may affect the nuclear surface capability to initiate the growth of perinuclear microtubules, thus blocking the prophase spindle formation. It also disturbs the spatial interaction between microtubules, which is crucial for the formation and functioning of various microtubular systems (preprophase band, spindle and phragmoplast).

Allium↗
PubMed2002

[Immunohistochemical identification of hormonally-inactive tumors of the adrenal gland].

An immunohistochemical study was carried out to differentiate between such neoplasms of the cortical and cerebral layers of the adrenal as adrenocortical tumor and pheochromocytoma. It used antibodies to chromogranin A, synaptophysin, vimentin, cytokeratin 8, pancytokeratin, carcinoembryonic antigen, epithelial membrane antigen, neurofilaments, alpha-fetoprotein, alpha-antitripsin and neuron-specific enolase. Chromogranin A and synaptophysin appeared to be immunohistochemical markers for pheochromocytoma since it responded negatively to vimentin and cytokeratin. Adenocortical tumors were associated with positive reaction to vimentin and a negative one to cytokeratin. These characteristics were used to differentiate adrenocortical tumors from adenomas which responded to cytokeratin and hardly to vimentin. A possibility of adrenal tumors consisting of endocrine and neurogenic cells is considered.

Adrenal Gland Neoplasms↗
PubMed2001

Effect of amylin on mast cell secretion as a possible mechanism increasing gastric mucosa resistance.

Water-immersion restraint stress increased secretory activity of mast cells and led to the formation of erosive lesions in the gastric mucosa. Intraperitoneal administration of amylin in a dose of 0.5 microg/kg 1 h before stress suppressed degranulation of mast cells and decreased the severity of gastric mucosa damages. In in vitro experiments amylin abolished the activating effects of acetylcholine and bradykinin on mast cell degranulation. Amylin-induced stabilization of activated mast cells probably underlies its protective effects during ulceration.

Acetylcholine↗