V. N. Pogorelova

Amino Acid Correction of Regulatory Volume Decrease Evoked by Hypotonic Stress in Mouse Oocytes In Vitro

Regulatory volume decrease in response to hypotonic stress is typical of the oocytes and early mouse embryos. Changes in the kinetics of osmotic reaction can be used as a marker of the modulating effect of the incubation medium on transmembrane transport in embryonic cells. Quantitative laser scanning microtomography (QLSM) was used to measure oocyte volume. In this paper, it is shown that addition of 5 μM glycine, taurine, or GABA, as well as ATP to Dulbecco’s medium abolished the regulatory volume decrease in mature mouse oocytes.

Scanning Electron Microscopy of Biofilms Adherent to the Inner Catheter Surface

The inner surface of the drainage catheter used in surgical interventions for biliary system pathologies was examined by scanning electron microscopy. Microfl ora in the catheter lumen refl ects etiological characteristics of the pathological process and helps to predict possible complications. The developed scanning electron microscopy imaging technique of visualization of the fi ne spatial structure of microbial biofi lm formed on the catheter surface allows describing the cell pool and structure of the biofi lm.

Scanning Electron Microscopy of Biosynthetic Wound Dressings Biocol

The surface of wound dressing Biocol was studied by scanning electron microscopy. This composite system consists of latex matrix with incorporated water-soluble polysaccharide. The peculiarities of the surface are important for manufacturing of the dressing and for modifi cation of its surface upon contact with fl uids, e.g. during de novo tissue reconstruction. The method for studying the fi ne structure of the polymeric fi lm surface was developed. The relief of the wound dressing changes during interaction with the fl uid and nanopores appear on the surface. Thus, scanning electron microscopy is an informative method for studying the surface of biosynthetic films.

Hypoxia during mammalian preimplantation development: Extreme circumstance vs. typical environment

The given paper summarizes the data on the early mammalian embryo development in culture media containing low oxygen concentration. Experimental results on in vitro modeling the hypoxia for preimplantation development are reviewed. Hypoxic conditions were shown to be available in the female reproductive tract of different mammalian species. The estimation of the embryo developing in vitro exhibits that lower oxygen level in culture media improves embryonic quality.

Comparative study of vasaprostan and alprostan in spontaneous platelet aggregation test in mice.

We propose a method for evaluation of spontaneous aggregation of mouse platelets based on routine clinical blood tests for humans. Comparative analysis of Vasaprostan and Alprostan drugs showed that this test can be used for testing of new drugs on animals.

The Use of ToF-SIMS for Analysis of Bioorganic Samples

The technique for the preparation of biological tissue sections developed for Electron Probe Microanalysis has been adapted for ToF-SIMS analysis of mouse GV stage oocytes. GV-oocyte sample preparation involves the following steps: plunge freezing, freeze drying, impregnation in an embedding medium, and section cutting. Molecule-specific images of the distribution of molecules in a single oocyte have been obtained with the described technique and ToF-SIMS analysis. The ToF-SIMS analysis data show that the efficient lateral image resolution is approximately 1 μm. Hence, ToF-SIMS enables us to study the distribution of chemical substances in relation to the morphological data obtained by scanning electron microscopy or conventional light microscopy.

Electrochemically Reduced Water: Modification of the Incubation Medium and Oxidative Activity

It has been shown that Dulbecco’s incubation medium prepared with electrochemically reduced water compensates for oxidative stress induced by hydrogen peroxide addition (H2O2, 0.2 mM) to the incubation medium. The incubation medium modified in this way does not affect the H2O2 induced apoptosis in an early mouse embryo. The embryonic cell in the experimental model of apoptosis shows the presence of characteristic morphological changes and decreased cell volume. These apoptosis-related changes were detected using laser-scanning microtomography.

High Potassium Concentration during Culturing of Early Mammalian Embryos: Normal or Extreme Situation?

Analysis of the element composition of oviduct and uterine fluid in mammals showed high potassium concentrations in the early embryo microenvironment in vivo. The results of early embryogenesis of mammals in vitro in the presence of high potassium concentrations are discussed. The data are summarized in accordance with the conditions of experimentally modeled pre-implantation development. Comparative assessment of the quality of embryo development until the blastocyst stage in vitro proved the embryos more successfully developed at potassium concentrations close to those registered in the oviductal fluid.

Nonspecific effect of Na+/K+-ATPase inhibition with strophanthin or under hypothermia in rat heart

Electron probe microanalysis was applied to study the kinetics of changes in potassium and sodium concentration in muscle cells of isolated heart from Wistar rat during experimental ischemia. Hypoxic perfusion without glucose was shown to evoke the potassium deficiency and sodium accumulation in cardiac myocells. Short-term action (10 min) of strophanthin (0.1 mM/L) recovered Na/K balance in ischemic myocells. Hypothermic perfusion exhibited the opportunity to conserve the cytoplasmic elemental contents in the state corresponding to the beginning of low temperature (4°C) operation.

Electron probe microanalysis of rubidium retention in myocell of rat heart during acute ischemia

In the given investigation contents of potassium and its physiological analog, rubidium, are determined in cardiomyocyte. Applying Electron Probe Microanalysis (EPMA), cytoplasmic concentrations of elements (K, Rb) are measured. The data obtained exhibit that for initial acute ischemia phase the active transport is involved in the uptake of rubidium which competes with potassium entry in cardiac myocell. Then, deep deenergization leads to the intracellular potassium depletion and rubidium retention. This suggests that Rb+ is physiologically not complete analog for K+. Results of combined perfusion with and without rubidium allow us to hypothesize the appearance of cascade of ionic transports to compensate acute ischemic disturbances following the oxygen and substrate deficiency.