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Biomedical subjects

S V Grachev

Publications and source records attributed to S V Grachev.

At least 19 recordsLinked to original sources
PubMed2006

The efficiency of calcitonin transport across the C-cell-blood barrier in rat thyroid.

This paper studies calcitonin (CT) transport across the C-cell-blood (CCB) barrier in normal rats. The efficiency of this transport is expressed as endogenous calcitonin bioavailability (F(CT)), i.e., that portion of CT molecules extruded by the thyroid C-cell basal pole that enters the circulating blood. Because currently F(CT) cannot be estimated directly, a novel methodology was used for its estimation. The essence of this methodology is to assess the CT level before and after the CCB barrier, to study these input-output CT relationships mathematically, and to find the F(CT) range allowed by the relationships. In this context, the subplasmalemmal granule numerical density in the C-cell basal pole (X) and the CT concentration in the right ventricular blood (Y) were found to be highly correlated: r(xy) = 0.922, P < 0.001; the covariance coefficient rho(xy) = 0.9980, P < 0.0001. Clearly, the overall variance of these input-output relationships in the covariance model (square root Var(xy) = 6.32) is explained, specifically, by CT retention (R(CT)) variability at the CCB transport stages. The greater the R(CT) mean value in the studied rats, the greater is the impact of R(CT) variability on Var(xy). The estimated variance caused by R(CT) (Var(CCBR)) makes it possible to determine R(CT) and F(CT) (F(CT) = 100% - R(CT)). Thus we estimated Var(CCBR) as Var(CCBR) < Var(xy) - CV(RIA)(2), where CV(RIA)(2) is CT assay variance: square root Var(CCBR) = 6.00% (P > or = 0.95). We then estimated F(CT) as the value range that does not contradict the Var(CCBR) obtained: 62% < F(CT) < 100% (P > or = 0.95).

Animals↗
PubMed2004

[A clinical and pathothysiological study of protein C in patients with generalized meningococcosis].

The clinical-and-pathogenetic significance of protein C was dynamically investigated within the infection processes in 23 patients (mean age 44 years) with meningococcemia. A reliably lower concentration of protein C in blood plasma (mean 37.8%) was registered versus the normal parameters (N = 70-130%) at exacerbation irrespective of a disease outcome. Leyden mutation was detected in 30.5% of patients. The presence of the above genetic defect denoted a predisposition to a severe disseminated intravascular coagulation (DIC) syndrome in patients of the studied group. A lower concentration of protein C was detected in blood plasma of patients with meningococcemia; it correlated with severity of the infection process and with the development of organic malfunction. The study of the concentration of protein C enabled an evaluation of the functional condition of anticoagulation mechanisms in the DIC development and can be regarded as an important extra criterion for the evaluation of thrombohemorrhagic syndrome in patients with meningococcemia.

Adolescent↗
PubMed2003

Role of matrix metalloproteinases and their inhibitors in tumor invasion and metastasis.

The role of various matrix metalloproteinases (MMP)--such as gelatinases, stromelysins, matrilysin, collagenase-3, and membrane-bound MMP (MB-MMP)--in tumor invasion and metastasis is discussed. Data suggesting significance for malignant growth of the expression level of these enzymes and also of their activators and inhibitors are presented. It is concluded that at different stages of tumor progression the activity of different MMPs is displayed, which is regulated by various growth factors and oncogenes. Different malignancies are characterized by changes in activities of specific MMPs. Data are presented which show significance of the ratio between the MMP activity and that of tissue inhibitors of metalloproteinases (TIMP) in tumor invasion and metastasis, especially in connection with a dual role of TIMP as both MMP inhibitors and activators.

Humans↗
PubMed2003

[Application of elliptical cylinder as a novel model of microvessel shape for analysis of thyroid capillaries in hypercalcemia].

Previously designed stereological method for estimating axial ratios (X0/Y0) of microvessels (MVs) whose shape is approximated by elliptical cylinders was applied for analysis in the rat thyroid perifollicular hemocapillaries in hypercalcemia (Ca gluconate--10% i.m., 0.7 ml/day, for 3 days). Electron microscopy revealed the size of major (X) and minor (Y) radii of ectioning profiles of the capillaries. The X/Y distribution corresponded to use of characteristics foe elliptical cylinder model's stochastically geometric 3D/2D relation of distribution of two--or three-dimensional (3D), and observed, or two-dimensional (2D), axial ratio values. The X0/Y0 values of the MVs under study were estimated as X0/Y0 approximately 1.3 for 79% and X0/Y0 approximately 2.7 for 21% of capillaries. The estimates obtained are of comparable value with the X0/Y0 calculated previously for the thyroid capillaries of the normal rat. They can be employed in physiological studies of the MVs.

Animals↗
PubMed2002

[Pathogenesis of gallbladder cholesterolemia].

Disturbances in cholesterol metabolism may be essential in pathogenesis of gallbladder cholesterosis (GBC). HDL cholesterol in the blood is subnormal. Physicochemical changes in the superficial layer of HDL induce impairment of free cholesterol esterification. Blood lipids and their apoprotein component are important for bile cholesterol level. In gallbladder contractile dysfunction but unaffected absorption there is enhanced passive and active cholesterol transport from the supersaturated bile to the cytoplasm of the epithelial cells from the bladder mucosa. Mechanism of intensive absorption of the lipids by macrophages operates primarily via modification of their apoprotein component. Modification of apoprotein occurs both in blood and gallbladder. Modified apoprotein is recognized by the macrophage and is absorbed by it together with transported lipids. In accumulation of great quantities of lipids in the macrophage it becomes big, slow, stays in the mucous or submucous layer of the wall and finally transforms into the foam cell. Moreover, deterioration of HDL cholesterol acception in GBC leads to slow discharge of cholesterol from the bladder wall.

Adult↗
PubMed2002

[Use of gas flow with nitrogen oxide (NO-therapy) in combined treatment of purulent wounds].

NO-therapy was used in 40 patients with purulent wounds of soft tissues. Bacteriological, cytological and morphological examinations demonstrated acceleration of wound process compared with control group (40 patients without NO-therapy). Laser doppler flowmetry demonstrated significant improvement of microcirculation in wound zone during NO-therapy. This method shortens by 3-5 days the time of preparation of wound surface for surgical closure.

Adolescent↗
PubMed2001

Matrix metalloproteinases of normal human tissues.

This review considers biochemical properties of the family of matrix metalloproteinases (MMPs) of normal human tissues and the involvement of these enzymes in morphogenesis. Four main MMP subfamilies are characterized, and a group of other MMPs is described. Data on mechanisms of activation and inhibition of MMPs in certain tissues during various physiological processes (embryogenesis, angiogenesis, tissue growth and involution) are considered. Information about tissue inhibitors of MMP is presented, and the ability of these inhibitors to regulate the activity of MMPs is analyzed.

Humans↗
PubMed2001

[Priming-phenomenon of neutrophils in patients with Flexner infection].

AIM: To study reproducibility of priming phenomenon of neutrophils in patients with acute Flexner's dysentery and its realization manifestation. MATERIAL AND METHODS: A chemiluminescent response of peripheral blood neutrophils was studied in patients with acute mild and moderate dysentery in the presence of luminol. Lipopolysaccharide Salmonella typhimurium at a final concentration of 20 ng/ml served as a priming substance of S-chemotype. Neutrophils were stimulated with phorbol myristate acetate in concentration 10(-6) M and isolated on Histopaque double gradient (Sigma reagents, USA). RESULTS: In reproduction of priming-phenomenon in vitro on neutrophils of patients with acute Flexner's dysentery chemiluminescence amplitude increased 1.29-1.69-fold vs control. CONCLUSION: Priming-phenomenon on neutrophils in acute dysentery is reproducible. This confirms modulating properties of lipopolysaccharides in conditions of systemic nonphysiological endotoxinemia. Priming phenomenon may be involved in both maintenance of homeostasis and pathophysiological processes.

Acute Disease↗
PubMed2001

[Immunomorphologic detection of apoprotein B antigenic determinants in the gallbladder wall in cholesterosis and cholelithiasis].

The presence and location of apoprotein B (Apo B) antigenic determinants in cholesterosis and cholelithiasis in gall bladder wall were detected for elaboration of modified Apo B role in pathogenesis of these diseases. Macroscopically changed parts of gall bladder (GB) wall of patients with gall bladder cholesterosis (GBC), and also macroscopically unchanged parts of GB wall of patients with cholelithiasis (CL) after cholecystectomy were studied. Macroscopically unchanged parts of GB wall obtained during autopsy of persons without symptoms of GB pathology were used as a control. Apo B location was studied with monoclonal (MAB 5F8 to Apo B) and polyclonal (PAB) antibodies; Apo B modified by malonic dialdehyde and oxidized by Cu2+ (4C11), Apo A with MAB1C5. Antibodies to CD 68 (specific marker of macrophages) was positive control, antibodies to trichinella--negative control. The most intensive accumulation of modified Apo B was revealed in foam cells region with accumulate lipids and form polyps that testifies to connection of apoproteins with lipids and foam cells and suggests their role in pathogenesis of GBC. More intensive staining of GB epithelial cells, particularly on GB peripheral parts by antibodies to apoproteins compared with surrounding tissues shows that bile is the source of detected modified apoproteins. Increase of absorption and accumulation of apoproteins in GB wall were also revealed in CL but these processes are less intensive than in GBS.

Adult↗
PubMed2000

[High-density lipoproteins in cholesterosis of the gall bladder].

The composition of serum high-density lipoproteins (HDL) was studied in 64 patients with polypous cholesterosis (PC). The spectrum of serum lipids in patients with PC was characterized by the lower concentrations of HDL cholesterol (42.0 +/- 2.5 mg/dl; p < 0.05) and higher concentrations of low-density lipoproteins (LDL) cholesterol (169.9 +/- 6.9 mg/dl; p < 0.01) than those in the controls. The decreased HDL cholesterol, or hypoalphacholesterolemia was associated with quantitative changes in HDL phospholipids (PL) (66.48 +/- 3.4; p < 0.01) and with changes in the composition of individual PL by lowering the proportion of lecithin (47.13 +/- 2.19 mg/dl; p < 0.01). It may be suggested that the lower amount of HDL cholesterol is caused by the decreased HDL acception of free cholesterol from the peripheral cell membranes due to the impaired complexation of PL with free cholesterol and associated the altered PL composition of the superficial monolayer of a lipoprotein particle. At the same time the physicochemical changes in Hdl superficial layer are a cause of abnormal free cholesterol esterification and the impaired plunge of esterified cholesterol into the nucleus of a HDL particle, which facilitates the conversion of HDL to LDL and may explain elevated LDL levels in cholesterosis. The findings suggest that serum lipids are involved in the development of cholesterosis.

Adolescent↗
PubMed2000

Role of matrix metalloproteinases in development of diabetic nephropathy.

This review considers molecular mechanisms that underlie disorders in the structure and metabolism of renal extracellular matrix in diabetic nephropathy. The contribution of the increased synthesis of renal extracellular matrix proteins in the accumulation of renal mesangial matrix is considered, and the important role of the degradation system of the extracellular matrix proteins in the development of fibrosis is also shown. Data on changes in mRNA expression for the matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) in various forms of diabetic nephropathy are presented. A correlation is established between changes in the balance of MMP proteolytic activity and TIMP activity and the accumulation of extracellular matrix.

Diabetic Nephropathies↗
PubMed2000

Morphometry error due to non-perpendicular section of microvessel characterized by two-dimensional isotropic arrangement.

Formulas for calculation of the section non-perpendicularity error in estimation of the perimeter and cross-sectional area of microvessel profiles are proposed for the two-dimensional isotropic approximation. A relationship was established between the bias and random error associated with non-perpendicularity corresponding to theta(min) for microvessel profiles meeting the condition theta(min) < or = B/C < or = 1, where B and C are the minimum and maximum axes of the microvessel profile, respectively.

Image Interpretation, Computer-Assisted↗
PubMed2000

[Ten-year activities of the Faculty for Training of Scientific and Pedagogical Personnel, I.M. Sechenov Moscow Medical Academy].

With the assistance and direct participation of the Presidium of the Russian Academy of Medical Sciences, the I. M. Sechenov Moscow Medical Academy has developed and introduced an unique elitist educational system to train of scientific and pedagogical staff at the pre- and postdiploma training stages on the basis of their close relationships and continuity, within whose framework a specially designed faculty has been successfully operating for 10 years. The basic principle that ensures its effective activity and solution of many didactic problems is the individualization and differentiation of an educational process by using a great diversity of reserves and organizational forms. The created system is unique in Russian and foreign practice. It improves the quality of scientific and pedagogical staff training, promotes more effective creation of staff reserves for the departments of higher educational establishments and research institutes of the Russian Academy of Medical Sciences and the Ministry of Health of the Russian Federation.

Academies and Institutes↗
PubMed2000

[Analysis of the annual open Russian competition for the best scientific student work in medical science].

For over 5 years, the I. M. Sechenov Moscow Medical Academy has been the basic Institute for holding the open Russian competition for the best scientific student work in medical sciences. The Academy has developed a methodological basis of this competition, which allowed the practical use of its organizational forms by the areas of informational support, evaluation of works, awards, office work. The authors' skills in presentation have become an original educational component in addition to usual expert estimation of works and afforded to obtain knowledge of progress in basic science and different problems in the organization of researches. The original competition organizing system has raised the popularity of the competition and the annual number of participants from different medical institutes and stimulated youth's interest in researches.

Competency-Based Education↗
PubMed1999

[Regulating activity of plasma membranous Ca2+ channels in PC-12 pheochromocytoma cells with chemicals and pharmaceutic agents].

The activity of the voltage-operated Ca2+ channels (VOC channels) and store-operated Ca(2+)-channels (SOC channels) was studied on rat pheochromatocytomic cells PC-12 by using the fluorescence calcium dye Fura-2. The VOC channels were transferred in their open state by depolarizing the plasma membranes of the cells through addition of high KCl concentrations (50 mM). The SOC channels were activated by treating the cells with tapsigargine, a special inhibitor of Ca2+ ATPase in the intracellular Ca2+ stores. Verapamil effectively inhibited the activity of the VOC channels (IC50 = 0.6 micron), but failed to affect the SOC channels. Arachidonic acid reduced the level of [Ca2+]-induced TG (200 nM) at a concentration of 3-10 microns). The movement of Ca2+ along the SOC channels was electrogenic. The depolarization of the plasma membrane of PC-12 cells caused no release of Ca(2+) from the intercellular Ca2+ stores. It is concluded that PC-12 cells are a suitable model to study the activity of different Ca2+ channels and search for chemical compounds that affect the potential-dependent and potential-independent Ca2+ channels.

Adrenal Gland Neoplasms↗