Biomedical subjects

L B Buravkova

Publications and source records attributed to L B Buravkova.

At least 19 recordsLinked to original sources

PubMed2005

Mesenchymal stem cells from human bone marrow and adipose tissue: isolation, characterization, and differentiation potentialities.

Comparative study of cultured human bone marrow and adipose tissue (lipoaspirate) mesenchymal stem cells was carried out. The main morphological parameters, proliferative activity, expression of surface and intracellular markers of these cells were characterized. Flow cytofluorometry and histological staining showed that both cell types exhibited similar expression of CD105, CD54, CD106, HLA-I markers, were positively stained for vimentin, ASMA, collagen-1, and fibronectin, but not HLA-DR, CD117, and hemopoietic cell markers. The cells underwent differentiation into adipocytes and osteoblasts under appropriate conditions of culturing. Incubation under neuroinductive conditions led to the appearance of a cell population positively stained for type III beta-tubulin (neuronal differentiation marker).

Adipose Tissue↗

PubMed2004

[Outcome of the long-term isolation on the development of allergic reactions in humans].

Studied were consequences of long-term isolation in airtight environment for development of the type-I (IgE-antibodies production) and type-IV (involvement of sensibilized T-lymphocytes) allergic reactions in humans. No significant changes in total IgE, specific IgE-antibodies for domestic, epidermal, fungal, grass pollen and food-borne allergens or serum IL-4 level were found in the period of the 240-d isolation with the microclimate and atmospheric parameters within their normal variations, and on completion of the experiment. Yet, after 3 mos. in isolation all subjects exhibited inhibited leukocyte migration in the presence of tuberculin. These findings bear witness to an activation of sensibilized lymphocytes known as effectors of delayed hypersensitivity.

Adult↗

PubMed2004

Cell interactions in microgravity: cytotoxic effects of natural killer cells in vitro.

To study cell-to-cell interactions in microgravity we examined the functional activity of natural killer cells on board of the ISS. NK cells are the effector cells with direct cytotoxic activity to oncogenic, virus-infected cells and cells with modified differentiation. Ground-based experiments have shown that the examination of target cell lysis after incubation with NK cells is a simple and informative model for studying the influence of microgravity. NK cytotoxicity was measured as the value of non-degradeted labeled myeloblasts (K-562) after 24 hrs exposure with human lymphocytes in suspension. A special device was developed for space flight experiments. Human cultured lymphocytes and labeled K-562 cells were loaded into special syringes and delivered to the Russian segment of the ISS. Cosmonauts prepared co-cultured suspensions during the first day of microgravity, exposed them at 37 degrees C for 24 hrs and then separated H3-labeled cells on special filters. The results of ISS-8 mission showed that human NK cells in vitro remain lysis activity toward target cells in microgravity. The basal level of NK cytotoxicity was low and we did not found significant differences between "control" and "flight" values. Interferon production during the interaction between immune and target cells (ratio 10:1) in microgravity did not differ compared with ground-based control experiments. Ground exposure of the same lymphocyte samples with K-562 cells to 24 hrs clinorotation also did not lead to significant differences. These experiments paved the way for understanding the cell interaction mechanisms in space flight and the obtained results suggest that microgravity does not disrupt the interaction of NK cells with tumor cells.

Cell Communication↗

PubMed2004

The primary effects of clinorotation on cultured human mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are specific cells capable of long-term proliferation and differentiation into various stromal tissue cell types. The state of MSCs depends on the cellular microenvironment and several soluble factors. We proposed that gravity could, in addition, influence MSCs features. To prove this hypothesis, we studied the effects of prolonged clinorotation on cultured human MSC morphology, proliferation rate and expression of specific cellular markers. Human bone marrow-derived MSCs were isolated by Histopaque-1.077 density centrifugation and cultured in DMEM-LG with 10% FBS. MSC cultures were composed of fibroblastoid cells negative for hemopoietic cell markers and positive for ASMA, collagen-1, fibronectin, CD54, CD105 and CD106. Cells were exposed to clinorotation from 1 hour to 10 days. It was shown that the proliferative rate was decreased in experimental cultures as compared to cells growing in normal conditions. Clinorotated MSCs appeared more flattened and reached confluence at a lower cell density. The obtained results suggest that cultured human mesenchymal stem cells sense the changes in gravity vector and may respond to microgravity by altered functional activity.

Actins↗

PubMed2003

[Antidiuretic reaction of the human and rat kidney to peroral administration of arginine-vasopressin and desmopressin].

Water in amount of 5 ml/100 g body weight was administered through a gastric probe into the stomach in alert rats; subjects-volunteers drank 20 ml of water per 1 kg of body weight. This resulted in diuresis at the peak of which the excreted water fraction reached 23% in rats and 12.4% in human subjects, whereas excretion of the osmotically free water amounted to 0.103 +/- 0.018 ml/min/100 g body weight and 10.0 +/- 1.8 ml/min/1.73 m2 of the body surface, respectively. These data indicate a practically complete inhibition of the arginine vasopressin secretion. On intragastric administration of 10 micrograms of arginine vasopressin or 0.2 microgram of desmopressin, with water in rats, a prolonged and quite obvious antidiuretic response occurred, with a marked increase of reabsorption of the osmotically free water in kidneys. A direct correlation has been found between the dose of the intragastrically administered vasopressin in the dose range from 0.1 to 10 micrograms/100 g body weight and a decrease of clearance of the osmotically free water. In subjects volunteers, an antidiuretic reaction to administration of 0.2 mg of desmopressin with water, was found. The data obtained provide a direct proof of intestinal absorption of nanopeptides without loss of their physiological activity. Significance of the data obtained for physiology of digestion and for clinical medicine, is discussed.

Administration, Oral↗

PubMed2003

[Effect of short-term hypoxia and re-oxygenation on mice peritoneal macrophages in vitro].

Microfluorimetry of single cells could help to analyze their morphology and function state during changes of gas environment. It is very important to have a possibility of the cell visual control during hypoxia and collection of dynamic fluorimetric data in digital form. The effects of short-term pO2 decrease were studied. For estimating the effects of hypoxia and reoxygenation we used the mice peritoneal macrophages, which are very sensitive to physical, chemical and regulatory stimuli. A special small chamber for fluorimetric measurements during pO2 changes, was developed. The level of active oxygen forms, intracellular pH, and cell membrane instability were investigated during replacement of air by nitrogen or argon (of the basal level decreased to 20% of basic level) and in subsequent reoxygenation. The increase of active oxygen forms was shown during 30 min of hypoxia and their level continued to rise immediately after reoxygenation. A short-term decrease and subsequent increase of pO2 in the medium led to an increase of intracellular pH level. The shifts of measured cell indices were stabilized after 30-40 min of pO2 changes thus suggesting a fast comprehension of countermeasure cell mechanisms. No macrophages with membrane disorders were found despite the rise of the active oxygen forms level during hypoxia and reoxygenation in vitro. There were no significant differences between nitrogen and argon used for replacement of air in the medium. The data obtained suggest a high resistance of macrophages against pO2 changes and an involvement of the antioxidative mechanisms for cell protection especially during reoxygenation period.

Animals↗

PubMed2001

[Alterations in actin cytoskeleton and rate of reparation of human endothelium (the wound-healing model) under the condition of clinostatting].

Effects of long-term simulation of hypogravity on actin cytoskeleton and cell migration were investigated in cultured human endothelium cells (EC). In control, F-actin resided predominantly on the periphery of cell forming an array of parallel bundles with "dense bodies" along the edge. A small number of actin cable fibers was found in the center. Already after 1-2 hrs of clinostatting at 5 RPM the cell cytoskeleton showed actin filament thinning and displacement toward the cell edges. In subsequent 6-18 hrs, almost all actin fibers had left the center part of EC and had ranged themselves in a continuous F-actin line in the intercellular contact area. In most cases, these changes resulted in the so-called "ruff-edge". Since both the disappearance of cable fibers and formation of the "ruff-edge" add to the cell migration activity, this parameter was studied with the would-healing model. According to our data, 24-48 hrs of exposure to hypogravity stimulates cell migration and expedites 2-3 times reparation of mechanically damaged monolayer. The results suggest that effects of hypogravity on cultured human EC are likely to be consequent to alterations in the activity of protein kinase C and/or adenylate cyclase involving many members of the cellular metabolism.

Actin Cytoskeleton↗

PubMed2001

[Effect of argon and nitrogen on the peritoneal macrophages in mice and their resistance to the UV damaging effect in vitro].

Explored were effects of argon and nitrogen on intracellular pH in peritoneal macrophages in mice and resistance of cellular membranes to the UV damaging effect in vitro. Blasting argon or nitrogen along the surface of cell cultures in airtight chamber for 20 minutes was shown to decrease 5-folds the oxygen content of solution as compared with initial level with culture pH unchanged. Ten-minute blasting argon or nitrogen through the incubation chamber slightly elevates intracellular pH in macrophages. The standard cell incubation conditions recovered following approximately 60 minutes in hypoxic atmosphere, the ability of macrophages to build up fluorescein was degraded and they increased intracellular pH no matter the indifferent gas yet more marked in case of nitrogen in use. It was demonstrated that the normobaric gas environment with oxygen partly replaced by nitrogen or argon protects plasmatic membranes of cells from UV-induced damage.

Animals↗

PubMed2001

[Morphological and functional study of human endothelium response to hyperthermia in vitro].

Effects of hyperthermia (+42.5 degrees C) on the endothelial monolayer organization, actin cytoskeleton and cell viability have been examined in culture of human aortic endothelial cells (EC). Short-lasting hyperthermia (1-4 hrs) provoked disappearance of stress fibers, redistribution of actin filaments to the area of cell-to-cell contacts, shape changes and reorganization of the monolayer. It also stimulated formation of intercellular contacts in a preconfluent EC culture. The cAMP content was elevated one hour after heat treatment and then lowered to negligible values (comparing to the basal cAMP level). Long-lasting hyperthermia (6-72 hrs) resulted in EC injury, and damage of endothelial monolayer accompanied by increased Chromium-51 release and almost complete blockade of [3H]-thymidine incorporation into DNA. Addition of cAMP elevating drugs (forskolin, 8-Br-cAMP or isobutylmethylxanthine) into the cell culture medium prevented heat-induced decrease in cAMP concentration, stimulated EC spreading, protected EC from injury, and promoted integrity of endothelial monolayers. Obtained results indicate that long-lasting hyperthermia can be regarded as an additional factor of endothelium injury involved in development of vascular pathology.

Aorta↗

PubMed2001

Expression of cell adhesion molecules and lymphocyte-endothelium interaction under simulated hypogravity in vitro.

Using histochemical staining and FACS-analysis we have studied the basal and TNF-alpha induced expression of E-selectin, ICAM-1 and VCAM-1 in human umbilical vein endothelial cells (ECs) exposed to simulated hypogravity. Control ECs did not contain detectable amounts of E-selectin or VCAM-1 but were ICAM-1 positive. As soon as after 6-8 hrs of clinorotation at 5 RPM the cellular content of ICAM- 1 increased. Moreover, hypogravity potentiated the effect of inflammatory cytokines (TNF-alpha and IL-1) on ICAM-1 expression. No increase in E-selectin or VCAM-1 expression was observed in ECs exposed to hypogravity itself. However, hypogravity reduced E-selectin and VCAM-1 expression in cell cultures activated by cytokines, more visible at their low (5-10 U/ml) concentrations. Both, control and clinorotated ECs poorly supported spontaneous lymphocyte adhesion; the adhesion of PMA-activated leukocytes was 15-20-fold higher. The interaction of unstimulated lymphocytes with cytokine-activated endothelium was more noticeable but significantly lower in cultures exposed to hypogravity. Activated blood cells interacted with endothelium more effectively, particularly, under hypogravity. Obtained results suggest that EC adhesion molecule expression and endothelium-lymphocyte interaction are altered under simulated hypogravity conditions in direction of increase of endotlielial adhesiveness for activated blood cells.

Cells, Cultured↗

PubMed2000

[Effect of increased pressure and changed gaseous media on biological properties of microorganisms].

Bacterial contamination of diving outfit and inner surfaces of pressure complex increases at the expense of expansion of gram-negative microflora during long exploitation of undersea complexes. Gram-negative bacteria were hypothesized to effectively adapt to hyperbaric conditions. We investigated the effect of hyperbaric conditions and changed gaseous environment on the cultural and morphological characteristics of colonies, growth rate and time of generation of test cultures (P. aeruginosa ATCC 10145, E. coli Tg1, and Bac. subtilis GB2036). Phenotypically modified clones were selected for subsequent analysis of changes at a genetic level. Experiments revealed no essential changes in the studied properties under the effect of extreme conditions.

Bacillus cereus↗

PubMed2000

[Gravitation sensitivity of human endothelium].

Experiments on the effects of hypogravity (clinostatting) on growth and formation of monolayer of cultivated endothelium cells of the human umbilical vein demonstrated sensitivity of endothelium to the gravitational stimulus as it responded by a significant reduction of the proliferative activity of cells in culture. The most favorable conditions for cultivating endothelium cells under extended (15-d) hypogravity in vitro were determined.

Adaptation, Physiological↗

PubMed2000

[Sensitivity in vitro of test-cultures and collection s of microoganisms isolated from surfaces of a pressurized complex to detergents].

Human subjects are a prime source of microbial contamination of the diving gear and the interior of deep-water diving complexes (DWDC). Disinfecting measures cannot ensure infectious safety of deep-water dives. Investigations in vitro were to compare effectiveness of a standard and a novel detergent against the microorganisms isolated from DWDC-250 at SRC-IBMP. It was discovered that 21% of microbial strains were resistant to the standard 3% solution of hydrogen peroxide. Diluted in ratio 1:10, polycept Demos (alkyl dimethyl benzyl ammonium chloride AB 0.5%) demonstrated 100% effectiveness in usual conditions and in hyperbaric experiments with various gaseous mixtures. Biocide Demos should be further tested during simulation of dives in DWDC-250.

Detergents↗

PubMed1999

[The use of microfluorimetric analysis for the studies of the influence of changed gravity on isolated lymphocytes in the spleen of the mouse].

Effects of simulated changed gravity on isolated splenetic lymphocytes of mouse were evaluated with the microfluorimetic technique enabling observation of probe fluorescence in individual cells. It was stated that 5 and 60 min of clinostatting stimulated fluorochrome accumulation in cells whereas centrifugation, particularly for 60-minutes, decreased the ability of cells to accumulate fluorescein. Also, alteration of the gravity force had the opposite effect on the ability of cells to retain fluorescein. The most significant drain of the dye immediately after short hypogravity may be indicative of the functional lability of cells during clinostatting. However, as judged by slight changes in intracellular pH, metabolic and regulatory functions were not affected. Hypergravity for 15 min decreased intracellular pH. The increased period of centrifugation stabilized the parameter. Absence of changes in the proliferative activity in all the test exposures also backs up the conclusion that short-term changes in gravity do not produce any substantial shifts in the morphofunctional state of cells in vitro.

Animals↗

PubMed1999

[The individual and integral effects of brief simulated descents and anesthetic pharmacological preparations on human metabolism].

In short-term chamber (GVK-250) "descents" by three healthy male volunteers mechanisms of hyperbaric narcosis against high partial pressures of indifferent nitrogen and argon were compared with anesthetic ketamine and sibason. Clinical biochemistry was engaged to determine any possible changes in metabolism due to the "descents" up to 0.4-0.6 MPa. Cubital vein blood was sampled prior to and following decompression. Plasma spectrophotometry was performed using biochemical analyzer EPAC-6140 (Eppendorf, Germany) and standard sets of reagents by Raichem (USA) and Biocon (Germany). On the whole, shifts in albumin, total protein, uric acid, lactate, and the creatine kinase activity were found to be within the physiological norm. However, several cases of excursion outside the boundaries of the clinical norm (A/T, AT, lactate dehydrogenase, triglycerides, lipase) could be associated with changes in the functional state of the liver caused by administration of the anesthetics during the hyperbaric exposure.

Adaptation, Physiological↗

PubMed1998

The influence of short term gravity changes on mouse spleen lymphocytes in vitro (microfluorimetry with probes).

Despite of the great successes achieved in gravitational cell biology, problem of mechanisms underlying cell effects of gravity is far from being solved. Available data are very contradictory, because of the differences in experimental conditions: gravity value, exposition time, type of cells and other factors. Besides, there are no satisfactory methods to avoid additional influence of various biologically active factors on cells during the space experiments. It is absolutely clear, that successful development in this field may be provided only by investigations in controlled experimental conditions, including analysis of cell functional activity and state of cell regulatory systems. One of the most adequate approaches for these scientific tasks is cell microfluorimetry with using of fluorescent probes. The study of influence of short-term pattern changes in gravity (clinostation and centrifugation) on hydrolytic activity of intracellular content of mouse spleen lymphocytes, leakage of accumulated fluoresce in and intracellular pH is the goal of present research.

Animals↗

PubMed1998

[Fatty acid composition of the lipids in human blood plasma and erythrocyte membranes during simulation of extravehicular activities of cosmonauts].

Dynamics of the lipoacidic content of total plasma lipids and erythtocyte membranes was studied in 32 experiments with ten apparently healthy male subjects aged 27 to 41 years who were exposed to repeated decompression from the normal ground down to 40-35 kPa. For two hours of exposure to lowered pressure the subjects were breathing pure oxygen in mask and performing incremental physical work mimicking loading of the upper extremities of cosmonauts doing extravehicular activities (EVA) at the energy cost of 3 kcal/min. Decompression sessions were repeated with intervals from 3 to 5 days. In seven experiments, the subjects developed symptoms of the decompression sickness (DCS). Penetration of gas bubbles (GB) into the pulmonary artery was registered in 27 cases (84.4%). In 24 cases maximal intensity of the US signals from GB reached 3 to 4 Spencer's points. No changes in the lipidoacidic content of blood plasma or erythrocyte membranes were determined following the first exposure to decompression. BY the onset of repeated decompression, total number of lipids in erythrocyte membranes decreased from 54.6 to 40.4 mg% in the group of subjects who had not displayed DCS symptoms (n = 5) and from 51.2 to 35.2 mg% (p < 0.05) in the group of subjects with DCS symptoms (n = 5). In the subjects with DCS, polyunsaturated linoleic acid (18:2) tended to decrease against the upward trend of saturated fatty acids (16:0, 18:0). In these subjects, arachidonic acid in erythrocyte membranes (20:4) decreased following each decompression exposure and significantly increased (p < 0.05) in-between. In both groups, blood plasma showed slight fluctuations in the lipoacidic contents. These data suggest that exposure to the variety of the EVA-simulating factors may entail quite distinct but reversible modifications in the lipid metabolism in blood and the structural/functional state of erythrocyte membranes. The most marked alterations were observed in the subjects with the DCS symptoms during high intensity of US signals from GB in the venous blood flow.

Adult↗

PubMed1997

Education programme on aerospace and environmental medicine for medical faculty of Lomonosov Moscow State University.

The problems and approaches to organisation of the education process in the field of aerospace and environmental medicine for medical students are discussed. Original education developed on the basis of Russian experience in space biology and physiology, environmental medicine, aerospace medicine and medical support during spaceflight. The main goals of these programs are to acquaint students with: interaction of living organisms with natural and artificial surroundings, including space flight conditions; the physiological reactions on extreme environmental factors; basic mechanisms of human adaptation to space flight and particularly to microgravity; the current research in space medicine and new telecommunication technologies. All programs are formed in accordance with contemporary progress in life sciences and revealed a result of the interdisciplinary approach to education process.

Aerospace Medicine↗