Biomedical subjects

L Buravkova

Publications and source records attributed to L Buravkova.

5 recordsLinked to original sources

PubMed2000

Simulated hypogravity stimulates cell spreading and wound healing in cultured human vascular endothelial cells.

It is well known that endothelial cells (EC) are highly sensitive to mechanical influences such as hemodynamic conditions or pulsatile stretch. However, it is still unknown, how endothelium responds to the changed gravity. The results of some studies suggest that cellular elements of vascular wall and, particularly, endothelium, may directly participate in development of physiological responces to microgravity. On our suggestion, this is extremely attractive since vascular endothelium is one of the main regulators of vascular tone (via its interaction with vascular smooth muscle cells) and, consequently, can play not last role in maintaining of normal cardiovascular system operation in microgravity. On the other hand, the endothelium itself may be regarded as a widely dispersed organ of approximately 1.5 kg in weight (in the adult human organism). Finally, endothelium is not just a passive barrier between vascular wall and circulating blood but synthesizes, metabolizes, and releases a substances which act on adjacent cell systems or distant cell structures. The main aims of this study were: 1) the development of experimental model, allowing to study functional parameters of human endothelial cells in hypogravity conditions in vitro; 2) the verification of endothelial sensitivity to gravitational micro-environment.

Cell Division↗

PubMed1997

Oxidative phosphorylation in rat skeletal muscles after space flight on board biosatellites.

Polarographic analysis of biological oxidation in rat's skeletal muscles after the 18- and 22-day flights revealed changes specific for the flight animals: oxidative phosphorylation uncoupling, distinct inertness of energy accumulation after 10 hrs of landing. Tissue respiration's inhibition was observed in both flight and synchronous rats suggesting the effect of other than microgravity factors. Energy metabolism in muscles of flight animals returned to the pre-flight level later (29 d) compared to the synchronous rats (6 d). Muscles of different functions (predominance of fast or slow fibers) showed similar responses of energy metabolism to weightlessness, i.e. inhibition of the intensity and decline of the energy efficiency of oxidative processes. A decrease in dehydrogenase activity has been found in the first day of recovery. The effects may be caused by the inhibition of both aerobic and anaerobic metabolism after space flight.

Animals↗

PubMed1996

Involvement of protein kinase C in hypoxia-induced desensitization of the beta-adrenergic system in human endothelial cells.

In order to better understand the mechanisms whereby oxygen deficiency promotes blunting of the endothelial beta-adrenergic receptor (beta-AR) system we examined the effects of hypoxia on beta-AR, adenylate cyclase (AC) activity and phosphoinositide turnover in cultures of human pulmonary artery and umbilical vein endothelial cells. 1 hr of hypobaric hypoxia (290 mm Hg) increased basal levels of inositol mono-, bis-, and tris-phosphate to those following histamine stimulation under normoxia. Basal and isoproterenol-stimulated AC activities were lowered after 1 hr of hypoxia. beta-AR density was decreased after 2-3 hrs of hypoxia and after treatment of EC with histamine, platelet activating factor or phorbol myristate acetate (PMA). In protein-kinase C (PK-C)-downregulated EC, neither hypoxia nor PMA influenced beta-AR density or AC activity. Hypoxia-induced desensitization of beta-AR signal transduction in EC may involve hypoxia-stimulated phosphoinositide turnover and subsequent PK-C activation.

Adrenergic beta-Agonists↗

PubMedDate not supplied

Cell-to-cell interactions in changed gravity: ground-based and flight experiments.

Cell-to-cell interactions play an important role in all physiological processes and are mediated by humoral and mechanical factors. Mechanosensitive cells (e.g., osteocytes, chondrocytes, and fibroblasts) can be studied ex vivo to understand the effects of an altered gravity environment. In particular, cultured endothelial cells (EC) are very sensitive to a broad spectrum of mechanical and biochemical stimuli. Earlier, we demonstrated that clinorotation leads to cytoskeletal remodeling in cultured ECs. Long-term gravity vector changes also modulate the expression of surface adhesion molecules (ICAM-1, E-selectin, VCAM-1) on cultured ECs. To study the interactions of geterological cells, we cocultured endothelial monolayers and human lymphocytes, immune cells and myeloleucemic (K-560) cells. It was found that, although clinorotation did not alter the basal adhesion level of non-activated immune cells on endothelial monolayers, the adhesion of PMA-activated lymphocytes was increased. During flight experiments onboard the Russian segment of the International Space Station, we measured the cytotoxic activity of natural killer (NK) cells incubated with labeled target cells. It was found that immune cells in microgravity retained their ability to contact, recognize, and destroy oncogenic cells in vitro. Together, our data concerning the effects of simulated and real microgravity suggest that, despite changes in the cytoskeleton, cell motility, and expression of adhesion molecules, cell-cell interactions are not compromised, thus preserving the critical physiological functions of immune and endothelial cells.

Cell Adhesion↗

PubMedDate not supplied

Blood biochemical parameters in women during long-term simulated hyperoxic diving up to 8 ATA.

Nowadays an increasing number of women are participating in recreational diving. A special recompression treatment table for delayed pulmonary barotrauma or decompression sickness was developed by V.V. Smolin in the Institute for Biomedical Problems (IBMP, Russia). The aim of our study was to investigate the effect of simulated dives (similar to this recompression treatment table) on biochemical parameters of healthy women. Three healthy female volunteers participated in long-term simulated diving to 8 ATA (0.8 MPa). Blood samples for determination of the biochemical substrate levels and activity of blood enzymes using a Reflotron analyzer were obtained at the control period, at the beginning of decompression and at the post dive period. No significant changes of serum levels of glucose, triglycerides, cholesterol, HDL cholesterol and urea were found during this experimental period or in comparison with the predive values. There were no significant changes in ALT activity in two volunteers but there was some tendency for an insignificant decrease in AST activity. One of the volunteers had a considerable increase in AST and ALT activities 15 h after the dive, probably due to a modified diet outside the experiment conditions. Thus, the long-term simulated diving recompression treatment table did not lead to a shift in the woman's serum biochemical status. However, it remains necessary to consider probable dysfunction of liver due to hyperbaric exposure.

Adult↗