Effect of desympathization on repair of the resected thyroid gland in adult rats

Department of Biology, Izhevsk Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR D. S. Sarkisov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 107, No. 3, pp. 353–356, March, 1989.     

A study of relation between hopelessness and causal attribution in school-aged children

This study was conducted to investigate the relation between hopelessness and causal attribution in Japanese school-aged children. In Study 1, the Japanese edition of hopelessness scale for children developed by Kazdin, French, Unis, Esveldt-Dawsan, and Sherick (1983) was constructed. Seventeen original items were translated into Japanese and they were administrated to 405 fifth- and sixth-graders. All of the items could be included to the Japanese edition of hopelessness scale. The reliability and validity was examined. In Study 2, the relation between hopelessness and causal attribution in children were investigated. The causal attribution questionnaire developed by Higuchi, Kambare, and Otsuka (1983) and the hopelessness scale developed by Study 1 were administered to 188 sixth-graders. Children with high scores in hopelessness scale significantly attributed negative events to much more effort factor than children with low scores. It supports neither the reformulated learned helplessness model nor the causal attribution theory of achievement motivation. It was explained mainly from points of self-serving attribution, cultural difference, and social desirability. Some questions were discussed for developing studies on depression and causal attribution in Japan.     

A simplified method of counting microorganisms in studying human autoflora

Formulae for the calculation of the count of microorganisms isolated from natural bacterial biocenoses of a child's body have been derived. The authors suggest a variant of simplified drip method for the computation of microorganism colonies in solid media. The described method helps cut down the nutrient media consumption at least 3-fold and is time-saving.     

Lack of effect of aspartame or of L-phenylalanine on photically induced myoclonus in the baboon, Papio papio

The effects of large doses of L-phenylalanine and of aspartame on seizure susceptibility and severity have been assessed in baboons Papio papio from Senegal which show photosensitive epileptic responses similar to primary generalised epilepsy in man. L-Phenylalanine, 50, 150 or 450 mg/kg, or aspartame, 300 or 1000 mg/kg, were administered orally. Peak plasma L-phenylalanine concentrations of approximately 2000 mumoles/l occurred 1-4 h after the highest dose of L-phenylalanine or aspartame. The plasma L-phenylalanine to large neutral amino acid ratio increased approximately 30-fold at this time. Compared with water administration there were no changes in epileptic responses 1-5 h after either treatment. In this primate model of epilepsy acute increases in plasma phenylalanine concentration are neither pro- nor anticonvulsant.     

Wall-thickness and midwall-radius variations in ventricular mechanics.

A fluid-fiber-collagen stress tensor is used to describe the rheology of the left ventricle of the heart. Linear theory is used to find the equilibrium solutions for the end-diastolic and end-systolic states of general axisymmetric shapes that are small perturbations of a thick-walled finite cylinder. The general problem can be studied by superposing the effects of variable midwall radius but constant wall thickness with those of variable wall thickness but constant midwall radius. A Fourier series representation is used to describe the midwall radius and thickness functions. Numerical calculations are performed to determine the deformed geometry and spatial distributions of tissue pressure, stresses, and fiber strains. The calculations proved to be highly accurate when compared to an analytical solution obtained for the special case of no fibers. The results show significant longitudinal differences when compared to results for the cylindrical geometry, with more sensitivity to variation in wall thickness than to variation in midwall radius.     

Reassessment of enkephalin (ENK)-containing afferents to the rat lateral septum with reference to the fine structures of septal ENK fibers

Using a combination of horseradish peroxidase (HRP) histochemistry and immuno-beta-galactosidase staining, and pre-embedding immuno-electron microscopy, the present study was intended to re-examine the origins of enkephalin-like immunoreactivity (ENKI) in the rat lateral septum (LS), and to show the fine structures of septal ENKI fibers. Following HRP injection into the LS, double-labeled cells which contained a homogeneous blue reaction product of ENKI and a black or brown granular reaction product of retrogradely transported HRP were identified in 4 discrete brain regions: perifornical hypothalamic area at the level of the paraventricular nucleus (PeF); posterior part of the anterior hypothalamic nucleus (AHP); bed nucleus of the stria terminalis, medial division, posterolateral part (BSTMPL); and dorsal hypothalamic area (DA). Immuno-electron micrographs demonstrated that some of the ENKI terminals in the LS form synapses with the soma and dendrites of septal neurons devoid of ENKI, though ENKI dendrites postsynaptic to non-immunoreactive terminals were also seen in the LS. These findings suggest that a large proportion of septal ENKI fibers have their origins in the above regions (PeF, AHP, BSTMPL, DA) different from the previously considered one, and they further provide a morphological basis for the postsynaptic inhibitory effects of enkephalins on septal neurons.     

D1 Dopamine receptor-mediated substance P depletion in the striatonigral neurons of rats subjected to neonatal dopaminergic denervation: implications for self-injurious behavior

The present study examined the influences of dopamine (DA) receptor stimulation on enkephalin (Met5-enkephalin; ME) and tachykinin (substance P; SP) systems of basal ganglia of Sprague-Dawley rats, lesioned as neonates with 6-hydroxydopamine (6-OHDA). It has been proposed that the neonatal 6-OHDA-lesioned rat could serve as a model for the DA deficiency and self-injurious behavior (SIB) observed in the childhood neurological disorder. Lesch-Nyhan syndrome. In agreement with earlier work, the present study found that the neonatal 6-OHDA treatment at 3 days of age, reduced DA and caused an increase in ME and a decrease in SP content in the striatum and substantia nigra, when tested as adults. Administration of the DA precursor, L-dihydroxyphenylalanine (L-DOPA), to lesioned animals, induced SIB; increased DA and DOPAC levels; produced a greater decrease (-64%) in SP levels in the striatum and substantia nigra than was observed with lesion alone (-28%). The L-DOPA-induced decrease in SP levels and the SIB observed in the lesioned animals were blocked by pretreatment with the D1 receptor antagonist, SCH-23390. Moreover, administration of the D1 receptor agonist, SKF-38393, but not the D2 agonist, LY-171555, to lesioned animals mimicked the L-DOPA responses in all respects, except that the agonists did not alter DA or DOPAC levels. None of the DA agonists or antagonists treatments affected lesion-induced increase in ME levels in the striatum. These results indicate for the first time, that SIB precipitated by DA agonists in neonatal dopaminergic denervated animals, is associated with a marked and selective decrease in SP in the striatonigral SP neurons. This process has two components: (a) a retarded development of the SP system due to neonatal dopaminergic denervation: and (b) a depletion of the remaining SP, presumably by enhanced release due to D1 DA receptor-mediated activation of striatonigral SP neurons.     

Effect of estrogen on calcium homeostasis and pituitary hormones in the growing chick

An experiment was carried out to investigate the effect of a range of estradiol (E2) doses (0.1-6.5 micrograms/g body wt/day) on vitamin D metabolism and the plasma levels of growth hormone (GH) and prolactin (PRL) in the growing chick. Doses of 0.5-0.7 microgram/g E2, which are insufficient to raise the plasma calcium level, did induce an increase in growth rate, an increase in 25-hydroxyvitamin D 1 alpha-hydroxylase (1-hydroxylase) and 24-hydroxylase activities, and an increase in plasma GH level. These parameters leveled off or fell over the dose range 1-2 micrograms/g E2 but there was evidence of a second peak in 1-hydroxylase activity at 6 micrograms/g E2. At this high dose rate, the plasma Ca level rose to 8 mM, as it does in the laying hen; 24-hydroxylase activity, growth rate, and plasma GH and plasma PRL levels all decreased. It was concluded that the dose response to estrogen in the growing chick is not linear and, in the case of 1-hydroxylase activity, may even be biphasic.     

Effect of bacterial purified antigenic fractions on natural defence mechanisms

The in vitro ability of bacterial purified antigenic fractions to interfere with the immune system has been investigated on human mononuclear cells from peripheral blood. Exposure of purified monocytes to the drug at concentrations from 1 to 1000 micrograms/ml, for different periods from 0 to 18 h, significantly increased cell-mediated cytotoxicity against TU5 target cells. Moreover, monocytes exposed for 1 to 18 h to drug concentrations from 0.1 to 1000 micrograms/ml released significant amounts of tumor necrosis factor alpha in a dose-dependent manner in the culture supernatants. The drug was also tested on natural killer (NK) cell activity; mononuclear cells exposed to antigenic fractions for different periods showed a significant increase of NK cytotoxic activity against K562 target cells after 3 and 6, but not 0 and 18 h. Active concentrations were from 1 to 100 micrograms/ml, higher and lower doses being ineffective. Bacterial purified antigenic fractions thus have some ability to interfere in vitro with mechanisms of cytolysis mediated by cells and soluble factors.