The dynamics of the direct current potentials of the brain during sustained attention in 10-11-year-old children

The dynamics of direct current potentials of the brain was studied in 10-11-year-old children during sustained attention to successive presentation of series of Shulte tables. Children were examined twice: before and after the series of training to fast reading. A gradual increase in the level of direct current potentials during sustained attention was observed. The increase was more pronounced in children with excessive than in children with moderate reactions to the loading. After the series of training to fast reading, the increase in the level of direct current potentials was reduced in both groups. This aftertraining neurophysiological phenomenon was combined with a transformation of psychophysiological characteristics: a decrease in the time of viewing of Shulte tables and increase in the speed of reading. It is suggested that the shifts of direct current potentials reflects the dynamics of intensity of the cerebral energy metabolism.     

Homeostatic non-shivering thermogenesis in humans facts and hypotheses

This review considers current research of different forms of non-shivering thermogenesis related to thermoregulatory and substrate homeostasis. The term “homeostatic non-shivering thermogenesis (HNST)” is proposed for explanation of facultative heat production stimulated by exposure to cold, food intake and accumulation of lactate during intensive muscle loading. Similarities and differences in physiological activity are displayed in three HNST types. Existence of a number of common points makes it possible to propose common physiological mechanisms of HNST realization. Among other candidates for HNST location, the brown adipose tissue (BAT) fits best as its function is specifi between thermogenic function in cold environment and diet-induced thermogenesis that makes it possible to link these two HNST types with BAT activity. Here we present the data indirectly confirming BAT functioning in processes of homeostatic normalization not related to cold acclimation or food intake. We also consider new data about BAT functional activity, its topographic body location, mechanisms of uncoupled respiration in different tissues in adult humans and about methods of BAT diagnostics which include the use of molecular markers. We list a number of facts confirming our suggestion about BAT activity being related to homeostatic normalization after physical loading. In conclusion, we propose an experimental research program for the testing of our hypothesis regarding BAT universal homeostatic function in humans.     

Preparation and characterization of monoclonal antibodies to human adiponectin for its quantitative measurement in serum

Mouse Monoclonal antibodies against human adiponectin were produced by the routine method and the specificity of antibodies was verified. These monoclonal antibodies (MoAbs) interacted with the monomeric and trimeric forms of recombinant adiponectin according to the results of a Western blot analysis. Human blood serum was fractionated by gel filtration, and the protein of these fractions was stained using labeled MoAbs. It was established that a single high-molecular-weight form (HMW) of endogenous adiponectin was detected by this method. The use of competitive enzymelinked immunoassay on the basis of the obtained MoAbs allowed us to show that the sera of healthy male donors contains lower adiponectin concentrations than that of female donors (8.42 ± 1.59 μg/ml vs. 11.01 ± 2.58 μg/ml, p = 0.01). We also detected statistically significant lower adiponectin levels in the serum of patients with coronary artery disease for both men (6.01 ± 2.73 μg/ml vs. 8.42 ± 1.59 μg/ml, p = 0.015) and women (5.79 ± 2.98 μg/ml vs. 11.01 ± 2.58 μg/ml, p = 0.0003). Therefore, the developed methods for the analysis of the HMW form of adiponectin can be helpful in the diagnostics of the possible implications and assessment of unfavorable prognoses in patients with cardiovascular disorders.     

Role of the vacuole in the redox homeostasis of plant cells

The review focuses on the mechanisms employed by plant vacuoles for maintaining the redox homeostasis under generation of reactive oxygen species (ROS) promoted by various abiotic stressors. These mechanisms are based on functioning of diverse enzymes and transport systems of the tonoplast as well as on vacuole-specific redox reactions involving vacuolar antioxidants of enzymatic and non-enzymatic nature. The established antioxidant role of plant vacuoles provides a clear example of closely integrated activities of this organelle with the metabolism of other cell parts.     

Dynamics of changes in the genome of callus tissues of <Emphasis Type="Italic">Rauwolfia serpentina</Emphasis> upon a switch to conditions of submerged cultivation

It is established that switching from surface to submerged cultivation in a liquid medium of a special composition does not induce noticeable changes in the callus tissues of Rauwolfia serpentina in the course of the first several passages. Polymorphism of the RAPD spectra is discovered following 4–6 growth passages of tissues in the submerged culture; this polymorphism may reflect both changes in the DNA sequence and in the genetic structure of the cell population forming the strain. Addition of an intermediate passage in a solid medium of simpler composition prior to a switch to the liquid medium does not exert a substantial influence on the level and nature of the changes in the genome.     

Fractionation of eukaryotic DNA in a pulsed electrical field. II. Discrete DNA fragments and level of structural organization of chromatin]

The data presented confirm the possibility of enzymatic formation of discrete DNA-fragments appearing during fractionation of nuclear DNA by FIGE. Teniposide-dependent pattern of DNA-fragments as well as occurrence of protein-linked DNA breaks suggest that discrete cleavage of intact nuclear DNA is modulated by DNA topoisomerase II. The possible relationship between discrete DNA-fragments and the higher order chromatin folding are discussed.     

Changes in the nucleoli of epithelial cells of the kidney tubules in mercuric chloride-induced experimental kidney tubular necrosis

Electron-microscopic studies of epithelial cells of uric tubules in white rat kidneys after i.m. injections of mercury dichloride (0.4 mg/100 of body weight) given every 24, 48 and 72 hours showed the affected epithelial cells to have nonspecific changes in tubule ultrastructure, i.e. dissociation and segregation of tubule components as well as degranulation, fragmentation and hypertrophy. The dissociation of nucleolus components is followed by the damage of an essential part of cell mitochondrial apparatus and becomes irreversible. In some damaged cells degranulation is accompanied by the nucleolus decay into separate solid fragments formed of fibrous tissue. The enlargement of nucleolus fragments in the absence of proribosomes speaks in favour of the depression of proribosome formation process while the ability to synthesize p-RNA in comparatively slight.     

Residual electron momentum and energy in a gas ionized by a short high-power laser pulse

A study is made of the nonadiabatic dynamics of photoelectrons produced during interaction of an elliptically polarized, high-power laser pulse with a gas. Expressions for the so-called residual momentum and energy of the electrons (i.e., the mean electron momentum and energy after the passage of the pulse through the gas) are derived. The residual electron momentum and energy are investigated analytically as functions of the gas and laser parameters. A relationship is established between the residual energy and the electron temperature tensor.     

Biochemical characteristics of the Ca2+ pumping ATPase in the peribacteroid membrane from broad bean root nodules

Ca²⁺-ATPase in the peribacteroid membrane (PBM) of symbiosomes isolated from Vicia faba root nodules was characterized in terms of its hydrolytic and transport activities. Both activities were found to be pH-dependent and exhibit pH optimum at pH 7.0. Translocation of Ca²⁺ through the PBM by the Ca²⁺-ATPase was shown to be fueled by ATP and other nucleotide triphosphates in the following order: ATP?>?ITP???GTP???UTP???CTP, the K _m of the enzyme for MgATP being about 100 μM. Ca-dependent ITP-hydrolytic activity of symbiosomes was investigated in the presence of the Ca-EGTA buffer system and showed the affinity of PBM Ca²⁺-ATPase for Ca²⁺ of about 0.1 μM. The transport activity of Ca²⁺-ATPase was inhibited by erythrosin B as well as orthovanadate, but markedly stimulated by calmodulin from bovine brain. These results allowed us to conclude that this enzyme belongs to IIB-type Ca²⁺-ATPases which are present in other plant membranes.