Natural Clinoptilolite Nanoparticles Coated with Phosphatidylcholine.

A nanocarrier was obtained by coating the natural clinoptilolite particle surface with a phosphatidylcholine layer. The shell effective size does not exceed the thickness of the phospholipid molecular layer, which was confirmed by UV spectrometry and molecular mass spectrometry. The hydrodynamic diameter of the formulated nanocarrier, which was determined by dynamic light scattering, is smaller than the clinoptilolite core size. This effect is assumed to be caused by the phospholipid shell, which reduces the aqueous medium friction. The nanosize of the formulated nanocarrier, the natural clinoptilolite core, and the phospholipid shell together allow a combination of fruitful features that can be used for the fabrication of multifunctional platforms for the delivery of biologically active substances, bioimaging, or as a basis for biosensors.

Laser Microtomography for IVF Oocyte of Human.

For in vitro fertilization technology, the quality of oocytes has a direct impact on the egg fertilization and developmental competence of early embryo. The morphological criteria are used for the estimation of oocyte quality before its fertilization in vitro. To date, only one method is known to determine the maturity of oocyte. This is the routine observation with a light microscope. The aim of this article was to adapt the noninvasive quantitative laser scanning microtomography (QLSM) for the investigation of morphological features of a human oocyte in vitro. This approach was used to accumulate the Z-stack gallery of optical sections of IVF oocyte. The layer-by-layer acquisition allows the fine cytoplasmic structure imaging. Applying the QLSM Z-stack of optical sections, the cellular volume was calculated with quantitative 3D reconstruction of a human oocyte. The volume value and intracellular structure were used as novel criteria to assess the oocyte state after the stress evoked by cryopreservation procedure.

Noninvasive Laser Microtomography of a Human Isolated Oocyte.

Using a non-invasive approach, quantitative laser scanning microtomography (QLSM), the morphology of human oocyte was studied layer-by-layer. Then, the cell volume was computed based on 3D reconstruction of a stack of optical sections obtained by QLSM. The integrity of oocyte membrane after cryopreservation was assessed by measuring the changes in oocyte volume in response to hypotonic shock.

Bacterial Film Disintegration with Electrochemically Reduced Water.

The aim of this work was to study the fine structure of bacterial films grown on the inner tube surface of a flow reactor. Using the scanning electron microscopy (SEM) approaches, the detailed biofilm relief was visualized. The action of electrochemically reduced water (ERW) on the biofilm ultrastructure generated by the plankton form of E. coli and/or lacto bacteria was investigated. The treatment with an ERW solution destroyed the biofilm organic polymer matrix and bacterial cells embedded in the matrix.

Disintegration of Bacterial Film by Electrochemically Activated Water Solution.

The structure of bacterial film formed at the inner surface of the recirculation reactor tube, is studied. The surface relief of the biofilm was visualized by scanning electron microscopy. The effect of electrochemically activated water solution on the film formed from planktonic lactobacteria or E. coli was studied. Treatment with electrochemically activated water solution destroys cells and polymeric matrix of the biofilm.

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.

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. Microflora in the catheter lumen reflects 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 biofilm formed on the catheter surface allows describing the cell pool and structure of the biofilm.

[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 degrees C) operation.

[Electrone 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.

[Cyto B dependent and ouabain insensitive regulatory volume decrease in bicellular mouse embryo].

Mouse single-cell embryos exhibit robust Regulatory Volume Decrease (RVD). In what manner the very early mammalian embryo following zygote stage is appreciably altered by the anisotonic extracellular solution is, as yet, totally unclear. Little attention was paid to this direction since there was no way to determine the blastomere volume. This work has served to quantitatively investigate the osmotic response of bicellular mouse embryos employing Laser Scanning Microtomography (LSM) followed with three-dimensional reconstruction (3 DR). We have shown that bicellular mouse embryos in hypotonic Dulbecco's experience RVD. Embryonic cells subjected to hyposmolar exhibit rapid osmotic swelling followed by gradual shrinking back toward their original volume. The van't Hoff law defines swelling phase with the effective hydraulic conductivity of 0.3 micron x min(-1) x atm(-1). Water release during RVD in bicellular mouse embryos is abolished by Cytochalasin B (Cyto B) and the volume recovery is insensitive to ouabain treatment.

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 modification of its surface upon contact with fluids, e.g. during de novo tissue reconstruction. The method for studying the fine structure of the polymeric film surface was developed. The relief of the wound dressing changes during interaction with the fluid and nanopores appear on the surface. Thus, scanning electron microscopy is an informative method for studying the surface of biosynthetic films.

Estimation of isotonic point of incubation medium for two-cell mouse embryo.

Osmolarity of Dulbecco's medium at which the volume of two-cell mouse embryo remained similar to that of intact embryo was determined. The method is based on comparison of kinetic curves describing the volume of embryonic cell in solutions of different osmolarity. The blastomere volume was measured by quantitative laser microtomography after fixed osmotic stress intervals. It was found that Dulbecco's saline with 125 mM NaCl solution is an isotonic solution for two-cell mouse embryo. This concentration corresponds to 290 mOsm, which is lower than osmolarity (~310 mOsm) of media routinely used for culturing of differentiated cells or biological fluids, e.g. blood plasma.

Evaluation of collagen gel microstructure by scanning electron microscopy.

We performed qualitative comparison of freeze drying and chemical drying as methods of preparing 3D wet specimens for scanning electron microscopy. Human fibroblasts immobilized in collagen gel were used as a model system. Specimens fixed with glutaraldehyde were frozen in liquid nitrogen and freeze-dried at low temperature in high vacuum. In parallel experiments, glutaraldehyde-fixed samples were dehydrated in ascending ethanol solutions, absolute ethanol, and 100% hexamethyldisilazane and then dried at room temperature. Scanning electron microscopy microphotographs of collagen fibers and cells were characterized by high resolution and the absence of collapsed or deformed structures even at high magnification (×50,000) for both chemical drying and high-vacuum freeze drying. However, high-vacuum freeze drying is superior to chemical drying for the investigation of the internal space of 3D scaffolds, because sample fracture can be prepared directly in liquid nitrogen. These techniques are a part of the sample preparation process for scanning electron microscopy and can also be used for studies of cell adhesion, morphology, and arrangement in wet specimens (3D gels and flexible tissue engineering scaffolds).

[Electron probe microanalysis of potassium, sodium, and chlorine levels in the cardiomyocyte cytoplasm during acute ischemia].

Electron probe microanalysis was applied to determine cytoplasmic elemental (K, Na, Cl) concentrations in cardiac cells of the rat (Wistar). Potassium, sodium and chlorine contents were measured in papillary muscle myocytes of the rat heart perfused by the Langendorff's procedure. Ischemic depletion was created by perfusion with deeply deoxygenated Tirode's solution in the absence of glucose. It was found that the initial phase of acute ischemia is characterized by the potassium deficiency and the accumulation of sodium and chlorine in cardiac myocytes. It should be noted that changes in the total charge of the main intracellular cations (K+, Na+) do not compensate for the increased chlorine concentration. This result can be accounted for by the appearance of ionic (K+ and Cl-) transport coupled with the removal of lactate anions produced in cardiomyocytes during anaerobic glycolysis.

Analysis of changes in cell volume of a mouse early embryo exposed to osmotic shock.

The impact of the osmotic component of the incubation medium for the volume of mouse early embryonic cell was studied by laser scanning microscopy. Common Dulbecco's medium caused a prolonged hyperosmotic effect. Adaptive phase of regulatory compensation for the osmotic shock was observed under hypotonic conditions. From these data, water permeability of the blastomer membrane is evaluated as 0.4 micro/(minxatm).

[Osmotic behavior of mouse embryonic cells subjected to hypotonic shock].

Osmotic adaptation in a blastomere of mouse embryo has been studied by the direct measurement of the cell volume using laser scanning microscopy microtomography followed by quantitative 3D reconstruction. Embryonic cells subjected to hypotonic shock first swelled and then returned to the initial size. At the beginning of osmotic stress, the swelling occurred by the van't Hoff equation with the water permeability coefficient (L(p)) of 0.4 micro x min(-1) atm(-1). The phase of the regulatory volume decrease was not abolished by Na+/K(+)-ATPase inhibition.

Quantitative microtomography of the early mammalian embryo by laser scanning microscopy.

The blastomer volume was measured by three-dimensional (3D) reconstruction of a series of successive optical sections of the early mouse embryo. Changes in cell volume during osmotic shock were studied. Incubation of a two-cell embryo in Dulbecco's medium induced slow shrinkage of the embryonic cells followed by recovery of its initial volume. A regulatory phase of osmotic shock compensation is characteristic of a blastomer under hypotonic conditions.

Effects of cytotoxins on intracellular na/K balance in mouse embryonic cell.

Cytoplasmic Na/K imbalance induced by cytotoxic substances (ethylene glycol and cytochalasin B) was studied. Incubation in Dulbecco's medium with these cytotoxins caused changes in K and Na concentrations in the mouse two-cell embryo blastomer. The effects of both substances resulted in a drop of Na content in the embryonic cell. Washing from cytochalasin B restored the initial Na/K balance in the cytoplasm. Possible adaptive mechanisms involved in the regulation of intracellular ionic homeostasis are discussed.