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The role of endogenous luteinizing hormone-releasing hormone (LHRH) in the development of concanavalin A (ConA)-induced proliferative responses was studied in rat fetuses. Preliminary treatment of fetuses in utero with either the LHRH receptor antagonist or anti-LHRH antibodies resulted in the suppression of ConA-induced proliferative responses of thymocytes. LHRH and LHRH-immunopositive cells, morphologically similar to thymocytes, were detected in intact fetal thymus. A significant content of LHRH was also found in the peripheral blood of fetuses. The LHRH content in thymus and plasma was similar in males and females. Surgical ablation of the hypothalamus resulted in 2-fold decreases in thymus and plasma levels of LHRH in 21-day-old fetuses compared to sham-operated fetuses. It was concluded that LHRH regulates mitogen-induced proliferative responses of thymocytes during prenatal ontogenesis in the rat. The main source of plasma LHRH at that period is the hypothalamus. Moreover, LHRH is synthesized in the fetal thymus. Thus, LHRH is suggested to have not only a central effect but also to be involved in autocrine or paracrine regulation of proliferative immune responses.

The application of film-forming organic polymers, which are in common use in membrane technology, as chromatographic adsorbents for packed and capillary columns has been suggested. The chromatographic characteristics of poly[1-(trimethylsilyl)-1-propine] (PTMSP) as an adsorbent were studied. The film-forming properties of PTMSP simplify manufacturing of capillary and packed gas-solid columns. It was shown that separation of C1-C4 hydrocarbon gases on the columns with PTMSP is of practical interest. In the authors' opinion, PTMSP is also promising for the separation of inorganic gases.

The effect of efficiency improvement of chromatographic system by injecting a sample at a lower carrier gas velocity (in comparison with the carrier gas velocity at subsequent separation) was studied experimentally and theoretically in isothermal gas-liquid chromatography. The suggested technique is based on sample introduction in the programmed carrier gas velocity operation mode: the injection is realized at low carrier gas velocity, then the velocity is increased rapidly up to the operation value. The technique can be applied in chromatographic practice.

Influence of helium and ammonia as carrier gases on retention of neutral solutes on polyethylene glycol has been studied theoretically and experimentally. It was shown that the influence of ammonia on the retention varied significantly depending on the solute's nature. For example, the influence is great for C22 n-alkane and it is small for phenol. Taking into account the results obtained by various researchers it makes sense to express an opinion on the expediency of development of gas chromatography operated under the conditions of acidic-basic chromatography.

The influence of ammonia as a basic carrier gas on the retention of acidic and basic solutes was experimentally studied. Use of the basic carrier gas (ammonia) leads to an increase in retention of acidic solutes. A simplified theory on the influence of carrier gas basicity influence on the retention of acidic and basic solutes was developed. Contact of an inert gas with ammonia water at ambient temperature can be used to obtain basic humid carrier gas and to improve the chromatographic characteristics of amine's zones.

The effect of endogenous luteinizing hormone-releasing hormone (LHRH) on the proliferation induced by concanavalin A (Con A) in rat fetal thymocytes was studied. A selective antagonist (2 microg per fetus) or antibodies to LHRH (20 microl per fetus) were injected in utero into 20-day-old rat fetuses, and this resulted in a two- or fivefold decrease in the Con A-induced proliferation of thymocytes, respectively. In combined culture of the antagonist (10-5-10-6 M) with fetal thymocytes, the proliferative response was not decreased. The concentration of LHRH was determined by radioimmunoassay in tissues of immunocompetent organs and in blood serum of 18- and 21-day-old fetuses, and the hormone was found in the hypothalamus, thymus, and peripheral blood. The initially low level of LHRH in the thymus increased by 65 and 40%, respectively, on the first day after birth and became similar to the level in the hypothalamus. In the fetal blood serum, the LHRH level was significantly higher than in the thymus and hypothalamus of fetuses of the same age. The hormone concentration was greatest in the 18-day-old fetuses, and it decreased twofold by the 21st day. The findings indicate that LHRH is involved in regulation of T-cell immunity even during prenatal ontogenesis.

The role of the neuroendocrine system in the development of cell-mediated immunity has been studied in fetal rats. The spontaneous and mitogen-induced proliferation of liver lymphocytes and thymocytes was evaluated in vitro in rats at the 22nd prenatal day following surgical ablation of the forebrain (encephalectomy) or of the entire brain and pituitary (decapitation) in rat fetuses in utero at the 18th day. Non-operated and sham-operated fetuses served as controls. The ablation of the entire brain and pituitary in rat fetuses resulted in an increase (40-60%) of spontaneous proliferation of liver and thymic cells in comparison with sham-operated fetuses. The ablation of the forebrain including the hypothalamus caused a decrease in the mitogenic proliferative response of thymocytes and liver lymphocytes for 40 and 20%, respectively. The ablation of the entire brain including the hypothalamus and pituitary resulted in a 80% decrease of the proliferative response of thymocytes and in the full suppression of proliferation of liver lymphocytes. The immune proliferative response was restored by the LHRH administration either systemically to operated fetuses (0.2 microg/fetus) or to the cell culture (10(-9) and 10(-7) M). It was concluded that the central nervous system was important for maturation of the immune system in rats during the prenatal period. In particular, neuroendocrine system are likely to play a major role as LHRH treatment in vitro and in vivo appeared to contribute to this regulation.

Optimal equation for fitting the experimental data on the height equivalent to a theoretical plate (HETP) versus carrier gas velocity in GLC was determined. The data obtained by authors and the literary data by other investigators were used for the comparative study of Van Deemter, Golay and the little known Golay-Guiochon equations. The Golay-Guiochon equation takes into account instrumental contribution and other sources of additional band broadening. Correlation coefficient R and Pirson's criterion chi2 were used as a criterion of the data correspondence to the equations. The Golay-Guiochon equation is the best for fitting of the experimental data in 71% considered examples, 19% experimental data may be fitted very precisely by the Van Deemter equation, the Golay equation is preferable for 7% experimental data only. Three percent experimental data may be fitted with the same precision by the Golay and the Van Deemter equations. The results obtained are of theoretical and practical interest. The Golay-Guiochon equation must be used more widely in analytical practice and physicochemical measurements.

In this study the influence of mu-, delta-, and kappa-selective opioid agonists (DAMGO, DSLET, and dynorphin A (1-13)) on cytoplasmic free Ca2+ ([Ca2+]i) level in normal and concanavalin-A (Con A)-activated mouse lymphocytes was investigated. [Ca2+]i was measured using the fluorescent dye FURA-2AM. The opioid peptides at 10-12-10-7 M induced some increase in [Ca2+]i in non-activated lymphocytes. However, DAMGO and DSLET (10-13-10-7 M) considerably inhibited a Con A-induced increase in [Ca2+]i. The inhibiting effect of both peptides was higher after 20-min preincubation compare to 2-h preincubation. The effect of the kappa-agonist dynorphin A (1-13) was significantly different depending on the duration of cell pretreatment and the concentration of the peptide used. After preincubation for 20 min at low concentrations (10-12-10-11 M) it slightly stimulated, while at higher (10-10-10-7 M) concentrations it inhibited lymphocyte response to Con A. After preincubation for 2 h, pronounced stimulation of mitogen-induced Ca2+ flux was observed at peptide concentration 10-9 M. The effects of opioids were antagonized by naloxone. These data indicate that functionally active opioid receptors expressed on lymphocytes could be involved in early stages of mitogen activation.

Cortical projections of the somatic system in the hedgehog cortex were studied by means of the evoked potential (EP) technique. The EPs were shown to arise at a large area of the lateral cortex, the area in question being enlarged under chloralose anaesthesia. In the focus of projection of corresponding modalities the EPs posessed the least latency. Functional differences in the EP generation system both in the focus of projection and outside it are discussed. The wide EPs spreading in the lateral cortex as well as the presence of relatively differentiated projections is supposed to depend on the afferent volley dispersion to the polysynaptic pathways at the thalamic level. Considerable overlapping of sensory projection zones in the cortex is conditioned by the latter and indicates low degree of the somatic analyser organization.

In the evolutionary series of vertebrates, a correlation was established between degrees of structural and functional organization of the brain and features of the formation of complex behavioral acts. Gradual evolution of a complex sequence of motor, food-obtaining, conditioned reflexes, and a capacity for visual discrimination in the phylogenetic line of vertebrates (cartilaginous and marine bony fishes, reptiles, and mammals--insectivores, rodents, and primates) was disclosed.

The differences in the cytoarchitectonic organization and the thalamocortical projections to the anterior and posterior cortical fields in cats provide the basis for judgements about their unequal roles in entire behavior acts. Extracellular recordings of anterior frontal neuronal activity have revealed the predominance of the nonspecific type of afferent activation of gyrus proreus neurons; complex integrative properties of gigantopyramidal neurones [posterior frontal regions] have been observed. Participation of the posterior frontal fields in afferent synthesis and in programming motor activity has been shown in behavioral studies. The phlogenetically younger anterior frontal fields are considered to be yet nonspecialized structures; posterior gigantopyramidal fields in cats are considered as the highest apparatus of programming complex motor activity in an experimental situation.

Food-getting conditioned motor reflexes to light and darkness discrimination were developed in elasmobranchs (the sharks Scyllium canicula and Galleus canis) and bony fishes (Mugil capitocum). Several distinctions in ecological and conditioned motor behavior were observed in sharks with low and high degrees of organization. There were significant differences between elasmobranchs and bony fishes in ecological and food-getting behavior and in conditioned reflex reactions. The nervous activity of elasmobranchs is characterized by a lower and more primitive degree of organization, compared to bony fishes.

The effect of an immunostimulator, Freund's complete adjuvant (FCA), on the ability of Wistar rats to learn in a visual discrimination test was studied by foodgetting and electric-shock avoidance methods. A significant improvement in learning ability was demonstrated under the influence of FCA when the negative reinforcement method was used, but a worsening when the positive reinforcement method was used. Analysis of the dynamics of extinction of the reflexes formed gave similar results. The possible relations between immunogenesis and memory forming processes are discussed.