Romanian journal of physiology : physiological sciences最新文献

The bilateral olfactory bulbectomy (OB) has been proposed as an animal model of depression. The present study, carried out on NMRI adult male mice kept on a natural LD 12:12 regimen, aimed to assess the influence of OB on the circadian rhythm of blood neutrophils phagocytosis. The results show that OB mice present an about 20% reduction of the basal phagocytic activity at 09.00 hrs, 15.00 hrs. and 21.00 hrs. and a 40% reduction at 03.00 hrs., leading to a flattened circadian phagocytic curve. The results indicate that bilateral olfactory bulbectomy depresses phagocytosis, alters its circadian rhythm and consequently increases susceptibility to infections.

Motion detection is an essential biological property of vertebral brain. In order to localize moving objects exactly, intrinsic time delays of the neuronal network must be compensated for. Invariance of position with regard to velocity of a stimulus due to a negative spatial shift is one option for compensation. Experimental results found in the present study support the view that negative spatial shift occurs in the visual cortex of the cat and the tectum of the frog. An order of 30% of the visual neurons may be suited to compensate intrinsic time delays.

The investigations were carried out on 30 Wistar albino male rats. A group of animals received Levodpa (Nakom), another group received Methyldopa (Dopegyt). One and a half hour after administration, the phagocytic activity was measured using colloidal carbon. Subsequent to Levodopa administration a significant increase occurred in the phagocytic activity. Following the treatment with Methyldopa the phagocytic activity in macrophages decreased. Our studies confirm the idea that the central adrenergic system stimulates the colloidopectic capacity of macrophages.

The Gregg phenomenon has not, yet, a full and complete explanation. We are allowed to consider it a "garden house"-like effect. Positive inotropic factors are released as a consequence of "shear stress" phenomenon following an increased coronarian flow. In our study, it is more probably a "garden house"-like effect that causes a sarcomere stretch. This could explain the increased left ventricle performance found, in some circumstances, in our study. We used the data obtained by coronarography in 22 patients carrying various degrees of coronarian obstruction and we assessed the left ventricle performance during the repeated injection of contrast medium, that increases the pressure in the coronarian bed. The results obtained support the theory regarding the Gregg effect but do not allow us to consider this effect as a fundamental determinant of the cardiac performance.

The proinflammatory cytokines tumor necrosis factor-a (TNF) and interleukin-1b (IL-1) play an important role in the pathogenesis of insulin-dependent diabetes mellitus, while TNF is also involved in promoting insulin resistance. It has been recently shown that glucose can induce the synthesis of TNF and IL-6 in human monocytes. The aim of the present study was to investigate the effect of glucose on unstimulated and lipopolysaccharide (LPS)-induced TNF and IL-1 production by human peripheral blood mononuclear cells (PBMC). No effect of glucose on spontaneous release of TNF or IL-I could be observed. The LPS-stimulated production of TNF was enhanced when cells were preincubated with increasing glucose concentrations. In contrast, no effect of glucose preincubation on LPS-induced IL-I synthesis was found. In conclusion, high glucose concentrations can increase the stimulated TNF production capacity, with possible important consequences for patients with diabetes mellitus.