Transmembranous currents of isolated spinal cord neurons of ammocete—Larva of the lamprey <Emphasis Type="Italic">Lampetra fluviatilis</Emphasis>

The work is carried out with aid of the patch-clamp method in the “whole cell” modification. There were studied potential-activated and chemosensitive currents of isolated spinal neurons of the lamprey larva-ammocete. The described properties of the currents indicate their similarities with those in adult lampreys.     

Cytology of oocytes in ground squirrels (Citellus citellus L.)

Oocytes of primordial, primary, growing, and Graaf follicles of the ovaries of 96 ground squirrels (Citellus citellus L.) were studied during the four seasons of the year. Multilamellar bodies in the oocytes were observed by electron microscopy. The bodies underwent changes during the follicle growth. The vesicles included in the multilamellar bodies were filled with an amorphous substance, while in Graaf follicles trapezoidal, rhomboidal, and hexagonal inclusions were found. The primordial follicle of the oocyte had no Balbiani body. In the hibernating ground squirrel the functions of the Balbiani body were probably performed by the multilamellar bodies, which were considered to be analogous to the Balbiani body.     

Homeostatic role of calcitonin antibodies in calcium metabolism in experimental diabetes mellitus

In experimental alloxan diabetes marked hypocalcemia and hyperglycemia are observed in the blood of rats during the acute period of the disease (from 1.5 to 2 months). After 2.5-3.5 months of diabetes calcium level reaches the upper normal limit. Simultaneously, antibodies to calcitonin appear. It is quite likely that excessive calcitonin secretion, leading to hypocalcemia, decreased insulin secretion and hyperglycemia take place in the acute stage of diabetes. When diabetes persists the antibodies to calcitonin which reveal a homeostatic reaction blocking the excess of calcitonin appear. This normalizes the level of calcium in the blood and prevents the further increase in the blood sugar level.     

In vitro and in silico investigation of interferonogenic analogues of nucleic acids, artificially programmed to block the initial stages of HIV infection of cells

Approaches to the molecular design of antiviral agents based on the principals of adequacy and mimicry to biopolymers have been discussed. The approaches permit for the reproduction of pharmaceutically valuable properties of the polymeric basis (core) and to create novel nongenetic “programs” of bioactivity of macromolecules by means of grafting specific side group combinations to this core. In vivo experiments have shown that the immunostimulating (in particular, interferon-inducing) antiviral potency of nucleic acids (NAs) is a characteristic of carboxylic acid analogues with an NA-type order of furan and anionic component alteration in the polymer chain. Controlled grafting of virus-targeted side groups of the polymeric basis leads to the direct blockage of viral infection in vitro as an additional antiviral effect. In this work, the inhibition of the early penetration stages of human immunodeficiency virus type 1 (HIV-1) in cells has been studied. Modelling of the macromolecule interaction with the most probable target (the virus-cell fusion mediator (an α-helical complex of the N- heptad repeat regions of three HIV-1 envelope glycoprotein gp41 transmembrane molecules) was performed. Computational docking of the experiment in silico resulted in the clarification of the putative mechanisms and parameters for the programming of site-tropic, axial, and belting blockages of the target via the application of an alicyclic-type side group. The discovered opportunities of multipoint axial cobelting blockage of a target opens up new prospects for the prevention/therapy of AIDS, as well as for other viral infections that use similar systems of envelope fusion peptides (of the first and third types) for penetration into cells.     

Seasonal changes of the ovarian atretic follicles of the ground squirrel (Citellus citellus L.)

The ovaries of 84 ground squirrels (C. Citellus L.) were studied during the four seasons of the year. The ovarian atretic follicles were examined by histological methods and by electron microscopy. The histoenzyme activities of NAD.H2-tetrazolium reductase, glucose-6-phosphate dehydrogenase, and 3 beta-hydroxy-delta 5-steroid dehydrogenase were photometrically demonstrated. The steroid-producing atretic follicles were mainly described as they reached their highest enzyme activity during the lactation period in April. The atresia of the primordial and primary follicles was manifested by disappearance of the oocyte and preservation of the granulose cells surrounded by basal lamina. Atresia of follicles with two oocytes was a typical process for the ground squirrel. Later on the oocytes and the granulose cells around it disappeared. The remaining part of the follicle continued its development and reached maturity. Atresia was observed mainly in March, April, and May.     

Role of long-term potentiation in mechanism of the conditioned learning

The review analyzes the fundamental problem of study of the neuronal mechanisms underlying processes of learning and memory. As a neuronal model of these phenomena there was considered one of the cellular phenomena that has characteristics similar with those in the process of “memorizing”—such as the long-term potentiation (LTP). LTP is easily reproduced in certain synapses of the central nervous system, specifically in synapses of hippocampus and amygdala. As the behavioral model of learning, there was used the conditioned learning, in frames of which production of the context-dependent/independent conditioned reaction was considered. Analysis of literature data showed that various stages of LTP produced on synapses of hippocampus or amygdala can be comparable with certain phases of the process of learning. Based on the exposed material the authors conclude that plastic changes of synapses of hippocampus and amygdala can represent the morphological substrate of some kinds of learning and memory.     

Toward the mathematical modeling of heat and mass transfer in vacuum freeze-drying: I. Thermodynamic analysis of heat- and mass-transfer processes in capillary porous materials undergoing freeze-drying

A number of existing mathematical models of heat- and mass-transfer processes taking place inside a material undergoing vacuum freeze-drying are reviewed in brief. Some physical considerations with respect to freeze-drying in a vacuum are presented and a corresponding mathematical model is proposed to describe coupled heat and mass transfer inside the material undergoing freeze-drying. The model is based on linear nonequilibrium thermodynamic results. After appropriate numerical analysis, the model is expected to yield new data to be utilized in vacuum freeze-drying design and technology.     

The ovarium of the hibernator (Citellus citellus L.) after spring arousal

The ovaries of 20 ground squirrels (Citellus citellus L.) were studied after spring arousal, while the animals were in the stage of estrus. The membrana granulosa of the preovulatory folic was luteinized. Epithelial cords were observed in the ovarial stroma. Cells in different stages of differentiation were found in the cords. For the first time nucleoli-like bodies in the nucleus and in the interstitial cells of the ovary of the ground squirrels. Probably, these nucleoli-like bodies played a definite role in the process of membrane formation during the cell differentiation. The NADH2 reductase and 3 beta-hydroxy-delta 5-steroid dehydrogenase activity confirmed that the process of differentiation of the interstitial cells was still in an initial stage. The findings were compared with the changes that took place during the puberty period.