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Biomedical subjects

E E Fesenko

Publications and source records attributed to E E Fesenko.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

[Activity of natural killer cells of the spleen of mice exposed to low-intensity of extremely high frequency electromagnetic radiation].

The dose dependence of natural killer (NK) cell activity from mouse spleen upon action of low-intensity millimeter waves in the exposure range from 5 to 96 hours was studied. It has found an increase of NK activity by 24 hours posttreatment that returned to normal level in a day after the cessation of the irradiation. Also the stimulation of isolated NK cell activity after millimeter waves treatment within 1 hour was revealed.

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[Three-dimensional reconstruction of synapse and dendritic spines in the hippocampus of rats and ground squirrels: new paradigms of the structure and function of a synapse].

The article reviews the literature data and results obtained by the authors concerning synaptic plasticity and remodeling of synaptic organelles in the central nervous system. Modern techniques of laser scanning confocal microscopy and serial thin sectioning for in vivo and in vitro studies of dendritic spines including a correlation between morphological changes and synaptic transmission efficiency are discussed, particularly, in relation to long-term potentiation. Organization of different types of dendritic spines and involvement of filopodia in spine genesis are examined. Significance of serial ultrathin sections for unbiased quantitative stereological analysis and three-dimensional reconstructions is discussed. The contact of one dendritic spine with two presynaptic boutons (multiple synapses) on both CA1 mushroom dendritic spines is discussed. The analyzed findings suggest new ideas for organization and functioning of synapses.

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[A comparison of the effects of millimeter and centimeter waves on tumor necrosis factor production in mouse cells].

The effects of millimeter (40 GHz) and centimeter (8.15-18.00 GHz) low-intensity waves on the production of tumor necrosis factor (TNE) in macrophages and lymphocytes from exposed mice as well as in exposed isolated cells were compared. It was found that the dynamics of TNF secretory activity of cells varies depending on the frequency and duration of exposure. The application of millimeter waves induced a nonmonotonous course of the dose-effect curve for TNF changes in macrophages and splenocytes. Alternately, a stimulation and a decrease in TNF production were observed following the application of millimeter waves. On the contrary, centimeter waves provoked an activation in cytokine production. It is proposed that, in contrast to millimeter waves, the single application of centimeter waves to animals (within 2 to 96 h) or isolated cells (within 0.5 to 2.5 h) induced a much more substantial stimulation of immunity.

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[The activity of natural killer cells in healthy and tumor-bearing mice after treatment with low-intensity laser light].

The effect of low-intensity laser light on the activity of natural killer cells from healthy and tumor-bearing mice was studied. Skin in the zone of the thymus or hind limb was illuminated, the remaining body surface being screened. The illumination was carried out for 30 days, with the duration of a single exposure being 1 min and intervals between the exposures being 48 h. The effect of laser light depended on the location of the illuminated area. It was shown that the exposure of the thymus of healthy animals for 20 and 30 days leads to a significant decrease in the activity of natural killer cells. On the contrary, the illumination of the limb for 10 or 20 days increased the activity of natural killer cells; but when hind limbs were treated for 30 days, the activity of natural killer cells decreased. Whereas tumor growth increased the natural killer cell activity, the illumination of tumor-bearing mice lowered the adaptive antitumoral resistance by decreasing the activity of natural killer cells.

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[Effects of exposure of different skin areas to low-power laser light].

The effect of helium-neon laser light of extremely low power of 0.2 mW/cm2 and wavelength 632.8 nm on the immune status of mice bearing solid tumors was studied. The evaluation of the status of tumor-bearing animals was provided by taking into account the number of immune cells, cytokine concentration (tumor necrosis factor, interleukin 2, production of nitric oxide, expression of heat shock proteins (Hsp70 and Hsp90), and activity of natural killers. The model of a solid tumor was formed by subcutaneous injection of Ehrlich carcinoma cells, and average life span of tumor-bearing mice achieved about 55 days. Different areas of the skin of tumor-bearing mice were subjected either to a single (1 min, dose 0.012 J/cm3) or repeated exposure to laser light (1 min, 48-h intervals, 30 days). Two different areas were irradiated: the thymus projection area or a hind limb with solid tumors. The results showed that chronic exposure of tumor-bearing mice in the thymus projection area, and especially, hind limb, reduced the resistance, which manifested itself in the acceleration of tumor growth and a tendency of mouse life span to decrease. On the contrary, a single exposure stimulated the antitumor immunity for several days after the exposure. The results show the expediency of further investigation of the immunomodulative effects of low-power laser light and the necessity of monitoring the immune system during laser therapy.

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[Increased survival of preimplantation mouse embryos in medium with recombinant cytokine LIF].

We studied the effects of cytokine LIF on in vitro development of 2-cell mouse embryos to the late blastocyst stage. LIF at 10 ng/ml enhanced the blastocyst formation and hatching from zona pellucida. When blastocysts were cultivated in a medium with LIF for a longer time, the trophoblast adhesive properties and proliferative activity were enhanced. In the presence of this cytokine, the trophoblast cells were attached to the substrate surface and fulfill the function of a sublayer for growth of the inner cell mass colonies with a high activity of endogenous alkaline phosphatase. Expression of LIF was detected in the oviduct and uterus epithelial tissues from day 1 until day 4 of pregnancy, thus suggesting its involvement in early development. According to the data of cultivation, cytokine LIF enhanced the adhesive properties and functional activity of the trophoblast cells, which is essential for implantation of blastocysts in the uterus.

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[Differentiation of embryonic stem cells into cardiomyocytes with the help of cytokine LIF (leukemia inhibitory factor)].

An experimental model of differentiated mouse embryonic stem cells with retractive activity similar to that of cardiomyocytes without preliminary formation of embryoid bodies was obtained. The basic factor that induced in vitro embryonic cell differentiation into cardial type is the recombinant cytokine LIF under prolonged cultivation. The positive reaction of the cells with retractive activity to isoproterenol indicates the presence of the beta-adrenergic receptor activity characteristic only for terminal differentiated mammalian cardiomyocytes.

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[Effect of low-intensity laser radiation (632.8 nm) on immune cells isolated from mice].

The effect of in vitro exposure to low-power laser light with a power density of 0.2 mW/cm2 and a wavelength of 632.8 nm induced by helium-neon laser on the functional activity of macrophages and splenic lymphocytes was studied. If the exposure period did not exceed 60 sec, the stimulation in interleukin-2 (IL-2) and nitric oxide (NO) production, as well as an increase in the activity of natural killer cells were observed. The increase of irradiation dose by prolongation of the exposure duration up to 180 s induced a significant decrease in NO production and natural killer cell activity, but IL-2 production was not different from the control level. A remarkable decrease in interferon-gamma (IFN-gamma) production was observed following laser light exposure of cells for 60 or 180 s, whereas under lower doses (exposure for 5 or 30 sec) IFN-gamma production increased. Irradiation of isolated macrophages induced a significant stimulation of cellular tumor necrosis factor-alpha (TNF- alpha) production at all dboes used, and, what is more important, an enhancement in both TNF-a phaand interleukin-6 (IL-6) production was revealed as early as after a 5-s exposure. In this case, more prolonged exposure periods, 60 and 180 s, either did not induce changes in IL-6 production (in macrophages) or decreased IL-6 production (in lymphocytes). Thus, upon in vitro exposure of cells to extremely low-power laser light, a basic tendency was observed: short-term irradiation predominantly induced stimulation in secretory activity of cells, whereas prolongation of exposure mainly induced immunosuppression. The only exception to the rule was a change in interleukin-3 (IL-3) production, which decreased after short-time exposure, but, on the opposite, increased when the cells were exposed for 180 s. In addition, a high sensitivity to extremely low-power laser light was supported by expression of the inducible heat shock protein, Hsp70, the effect being observed at all doses used, including the exposure for 5 s. At the same time, expression of another heat shock protein, Hsp90, was somewhat reduced after irradiation of cells with laser light.

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[Biophysical aspects of reconstruction of a single cell by the methods of cell engineering].

The problems of a low efficiency of mammalian cloning are discussed with emphasis on the necessity of the expertise of each step of single cell reconstruction, beginning with microsurgical manipulations. The fact of cell content leakage when the cell is held during microsurgery or microinjections with the help of the conventional method using negative pressure in the holding micropipette was demonstrated in experiments on murine embryos. It was shown that the rate of cell content efflux depends on the value of negative pressure generated in the holding micropipette, and is directly proportional to the dimensions of its orifice and the duration of micromanipulations. An alternative method of cell fixation using the capillary forces of the holding micropipette was proposed. The method optimizes the process of cell fixation, reducing the holding effort by two orders of magnitude. As a result, 92% of embryos remain viable after fixation of embryo, as compared with 39% in the conventional technique. In order to diminish the cell damage produced by the tip of a microinstrument, a new technique of fabricating micropipettes was proposed. The improved method of filling the micropipette with viscous liquids, including DNA, which is described in details in the paper, enabled constant (non-stop) microinjection of more than 1000 cells by hand, without any special automatic device.

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[Mechanism of signal transduction in photoreceptors of vertebrates: identification of an intracellular transmitter].

A short account is given of the studies which resulted in identification of cGMP as intracellular transmitter which realizes the control of light-depending channels of vertebrate photoreceptors. The following problems are discussed. 1. Proofs of necessary participation of intracellular mediator in the signal transduction in the photoreception act. 2. Competition between cGMP and Ca2+ ions for the role of such mediator in the photoreceptors of vertebrates. Relationship between metabolism of cGMP and Ca2+ which makes impossible identification of the mediator in the in vivo experiments. 3. Patch-clamp-experiments which have shown that conductivity of the rod plasma membrane is controlled by cGMP rather than by Ca2+ ions. Proofs of the identity of cGMP-regulated channels recorded in patch-clamp-experiments and light-dependent channels observed in the in vivo experiments. 4. Analysis of the prospects of further studies of the control mechanism of light-dependent channels.

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[Cation channels in the plasma membrane of retinal rod outer segments activated by cGMP].

Properties of cGMP-activated cation channels were investigated on isolated patches of the ROS plasma membrane using the "patch clamp" technique. The channels were shown to be characterized by ideal cation selectivity under physiological conditions and are nearly equally permeable for cations of alkaline metals. At the same time they are permeable for some bivalence cations (PNa approximately PCa). Other channel properties are described and their comparative analysis is given. It suggests that cGMP-activated cation channels represent a new type of cation channels.

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[Molecular mechanisms of photoreception. VI. Cyclic nucleotide- and light-dependent phosphorylation of rod outer segment proteins in the frog retina].

Phosphorylation of proteins in purified rod outer segment from frog retina was investigated. Phosphorylation of 18, 17, 12 and 11.5 kDa proteins was stimulated by cAMP (Ka approximately equal to 10(-7) M) and cGMP (Ka approximately equal to 10(-4) M). 32P-incorporation into 18 and 17 kDa proteins was much lower than into 12 and 11.5 kDa, which are in the group of main phosphoproteins of the rod outer segment: 12 and 11.5 kDA phosphoproteins appear to be present in cytoplasm or are slightly bound to disk's membranes. However, they are not discovered in the cytoplasmic membranes. The dephosphorylation of low-molecular weight proteins, discovered earlier by Polans et al., occurs slowly: the light doesn't change the level of phosphorylation of proteins in living retina within the time of photoresponse. It is suggested that the process of light-dependent phosphorylation-dephosphorylation of 12 and 11.5 kDa proteins controls the light sensitivity of the photoreceptor.

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[Isoelectric focusing of rhodopsin].

By method of isoelectric focusing in polyacrylamide gel and sucrose density gradient it has been shown that rhodopsin preparation, obtained by different methods (including the rhodopsin with low content of lipids) are divided into a number of fractions with isoelectric points at the pH-range 5.4-6.0. The corresponding preparations of opsin show heterogeneity in pI, too. Heterogeneity in pI remains at denaturation conditions (8 M urea, 0.01% beta-mercaptoethanol, 1 mM EDTA). If separated in this system at least two protein components are detected. The nature of heterogeneity in pI found and its possible connection with complicated kinetics of the decay of early intermediate products of visual pigment are discussed.

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PubMedDate not supplied

[Molecular mechanisms of photoreception. V. Isolation of cytoplasmic membranes of rod outer segments from the frog retina].

Cytoplasmic membranes of rod outer segments from frog retina intact rods in retina were stained with fluorescent dye fluoresceinmonomercur acetate. The dye is covalently bound to proteins of cytoplasmic membrane and doesn't penetrate into the cells. Upon isolation of the purified outer segments with the labeled cytoplasmic membranes the cells were disrupted and fractionated in density sucrose gradient. Cytoplasmic membranes possess floating densities different from those of disk membranes and thus providing a mean for separating them from the latter. The main peptides of cytoplasmic membranes are 56, 53, 45, 30 and 28 kDa proteins.

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[Development of olfactory epithelial grafts in the anterior chamber of the eye].

Olfactory epithelium of newborn rats was transplanted into the anterior eye chamber of the adult rat. Within 6-8 weeks the transplants increased in weight by a factor of 20-50. Morphological analysis has shown the cells similar to olfactory sensory neurones in the grafts. Electroolfactograms obtained with n-amyl acetate and camphor had the amplitude of about three times less and the duration of about 8-10 times more than those from the normal olfactory epithelium at the same concentration of stimuli. Within six hours after 3H-beta-alanine had been introduced into the anterior eye chamber, 72% of the label were present in the carnosine fraction. The data obtained suggest that olfactory sensory neurones appear in the olfactory epithelium grafts into the anterior eye chamber.

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