Comparative characteristics of cytosol glucocorticoid receptors from normal liver, the liver of tumor-bearing rats and hormone unresponsive Zajdela hepatoma]

Specific dexametasone (D) and cortisol (F) receptors have been found both in liver and Zajdela hepatoma. Rat liver cytosol receptors are characterized by the association constant (Kas) = 3,8 X 10(8) M-1 for D and 0,57 X 10(8) M-1 for F as well as by a number of binding sites (NBS)=4,9 X 10(-13) moles/mg protein and 4,06 X 10(-13) moles/mg protein, respectively. The receptors show stric specificity to glucocorticoids. Cytosol glucocorticoid-receptor complexes from liver and hepatoma sediment at 6-7S, when centrifuged in the buffer of a low ionic strength, and at 3-4S in the buffer of a high ionic strength (0,4 M KCl). The properties of cytosol receptors in the course of in vivo hepatoma growth were found to be gradually altering: Kas for D dropped whereas that for F increased; the NBS is decreased 3-4 fold as compared to normal liver cytosol--which may partially be accounted for by the unresponsiveness of the tumour to the hormones.     

Homogeneous Cl. perfringens alpha-anatoxin: its physicochemical and immunogenic properties]

The authors present a method of obtaining relatively homogeneous preparations of alpha-toxoid of Cl. perfringens, type A, including the primary conception of the alpha-toxin proteins, their chromatography on DEAE-cellulose, fractionation with (NH4)2SO4, detoxication, with the subsequent gel-filtration through sephadex and isoelectric focussing. Sedimentation coefficient of the preparation proved to be 3.8 S, isoelectric point-4.83 +/- 0.07. In studying the immunogenic properties of alpha-toxoid in experiments on guinea pigs and rabbits their high immunogenicity, exceeding that of the industrial toxoid 8- and 6-fold, respectively, was established. Homogeneous preparations of alpha-toxoid provided intense anti-microbial immunity. Interlinear differences in the levels of the immune response of inbred mice, highly-reactive (BALB/c) and low-reactive (C57BL/6) to alpha-toxoid, reached 20-fold; in combination with the high immunogenicity of this antigen for mice this permits to recommend it for immunogenic studies.     

Perception of the emotional component of vocal signals at different durations of the stimulus

The effect of the temporal structure of a vocal stimulus on the perception of the emotional component of the signal was studied in several age groups (7–10, 11–13, and 14–17 years). The experiments were performed at different durations of the stimulus (0.5, 1, 1.5, 2, and 3 s). ANOVA of the recognition efficiency and response time showed that the stimulus duration and the interactions of this factor with two others (stimulus duration × age and stimulus duration × emotion type) were highly significant for the recognition of emotions. The effects of the temporal structure of the signal on the recognition efficiency and response time were the strongest in the cases of neutral and negative emotional intonations and on going from the youngest to the middle age group. The minimal stimulus duration at which the threshold recognition of the emotion type occurred changed with age (from 2 s in the youngest age group to 0.5 s in the oldest). The capacity of the sensory acoustic memory was evaluated in children and adolescents of different ages.     

Perception of the Emotional Speech Component by Stuttering Children Associated with Noise: Communication II. Analysis of the Temporal Characteristics of the Recognition of Different Emotions

The reaction time for the recognition of different emotions in speech against a background of noise in stutterers and normally speaking children between the ages of 7 to 17 years was studied. The specific differences between these two types of subjects in processing the emotional speech component were more markedly pronounced in terms of the reaction time than the effectiveness of recognition. An increase in the noise level decreases the effectiveness of recognition and increases the reaction time; however, the stutterers do not show a statistically significant lengthening of the reaction time. With increasing age, the recognition time of the emotion type in both groups of subjects is shortened, although sex-related differences may be observed: only in stuttering girls is the difference in the recognition time between the junior and senior groups great enough and comparable to that of normally speaking girls. The stuttering children (SC) were found to have significantly shorter recognition times of the emotion types than their normally speaking counterparts. In this connection, the hypothesis about the specific features of processing the acoustic signal in the sensory memory of SC was advanced. These results suggest that the specific features of the processes occurring in the memory subsystems of stutterers may be one of the causes of stuttering, along with the differences in interhemispheric relations found in previous works.     

Helper B cells promote cytotoxic T cell survival and proliferation independently of antigen presentation through CD27/CD70 interactions

CD8-expressing cytotoxic T cell (CTL) interactions with APCs and helper T cells determine their function and ability to survive. In this study, we describe a novel interaction independent of Ag presentation between activated CTLs and bystander CD19-expressing B lymphocytes. Ag-stimulated CTLs serially engage autologous B lymphocytes through CD27/CD70 contact that promotes their survival and proliferation. Moreover, these interactions induce the release of proinflammatory cytokines that follows two general patterns: 1) an epitope-dependent enhancement of cytokine release, and 2) a previously undiscovered coordinate release of cytokines independent of epitope exposure. The latter includes chemoattractants targeting activated T cells. As a result, activated T cells are attracted to B cells, which exert a "helper" role in lymphatic organs or in areas of inflammation. This observation provides a mechanistic explanation to previously reported experimental observations suggesting that B cells are required for T cell priming in vivo.     

Existence of glucocorticoid-specific receptors in the plasma membranes of rat liver

It was found that isolated plasma membranes whose purity was assayed by determinations of marker enzyme activities, specifically bind dexamethasone. The association constant and the number of binding sites were found to be equal to (7,03 +/- 4,05) . 10(9) M-1 and (1,6 +/- 0,18) . 10(-14) mol/mg protein, respectively. It was assumed that lipoprotein components of plasma membranes are involved in this binding.     

Cryopreserved neurons of a mollusc are capable of morphological differentiation in culture in vitro

It was shown in culture in vitro that neurons isolated from the cryopreserved brain of adult molluscs Lymnaea stagnalis L. retain viability. Isolated brains were frozen in liquid nitrogen vapors at a rate of 400-500 degrees C/min in the presence of 2 M dimethylsulfoxide. The samples were then plunged into liquid nitrogen and stored from 1 month to 2 years. Upon thawing and removing the cryoprotectant, the neurons were isolated from the brain and then introduced into a cellular culture in vitro. It was shown that the thawed neurons were capable of regenerating new nerve processes similar to those formed by unfrozen neurons in the control.