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Fractions containing macrophage migration inhibition factor (MIF) and leucocyte migration inhibition factor (LIF) were obtained using Sephadex G-200 filtration from supernatant fluids of human lymphocyte cultures stimulated by PHA. The fractions were tested for the ability to affect migration and phagocytic activity of target cells. Peripheral blood leucocyte migration capacity was inhibited by the fraction with the molecular mass of 60,000-70,000 D (LIF), while migration activity of mouse peritoneal exudate cells was suppressed by the fraction with the molecular mass of 20,000-30,000 D (MIF). MIF- and LIF-containing fractions increased almost three-fold Fc-receptor-mediated phagocytic activity of neutrophils.  相似文献   
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The paper submits the results of studies on the kinetics of spermatogenous epithelium cell number after exposure to fast neutrons (60-300 cGy) and gamma-radiation (200-600 cGy). It was shown that a relative decrease in the quantity of spermatocytes is determined by an exponential dose-response curve with D0 of 35 and 120 cGy for neutrons and gamma-radiation respectively. For spermatides and spermatozoa a single D0 value of 20 and 55 cGy was obtained for neutrons and gamma-radiation respectively. As the radiation dose increases the recovery process in the epithelium is substantially decelerated. The equation T1/2 = T1/2(0)e0.0009D well describes the dependence of the half-recovery period T1/2 upon the equivalent dose.  相似文献   
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The cytotoxic and radiosensitizing effects of hyperthermia was shown on Ehrlich ascites tumor cells heated in vitro. The effect of hyperthermia resulted in the formation of local lesions in membranes of dying cells.  相似文献   
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THERE are two principal groups of theories of ageing—those which hold that random cell damage is chiefly responsible for the events characteristic of ageing, which culminate in death and those which hold that ageing and death are genetically controlled. It is too soon to decide between these points of view and in any case Bullough1 has shown that they are not mutually exclusive. So far experiments to test the random error theories of ageing, involving exposure of organisms to unnaturally large or even small amounts of agents such as X-rays and mutagenic agents (for reviews, see refs. 2 and 3), have been controversial and inconclusive.  相似文献   
279.
The paper is concerned with analysis of the results of intraoperative phlebotesticulography, performed in 50 patients with varicocele of degree I-II during Ivanissevich's operation. The effect of surgical intervention was shown to depend upon the quality of ligation of the testicular vein, some parts of which are anastomosed between themselves. The localization of this anastomosis is revealed by means of intraoperative phlebotesticulography, which permits increasing the results of surgical treatment and predicting a course of a postoperative period.  相似文献   
280.
Release of corticosterone in hungry kittiwake chicks facilitates begging and allows them to restore depleted energy reserves by increasing parental food provisioning. However, in order to avoid detrimental effects of chronic elevation of corticosterone, chicks might suppress adrenocortical activity in response to prolonged food shortages. In this study we examined temporal dynamics of corticosterone release in red-legged kittiwake (Rissa brevirostris) chicks exposed to prolonged restrictions in energy content and/or nutritional quality (low versus high lipid content) of their food. Starting at the age of 15 days, chicks were fed either high- or low-lipid fish at 40%, 65%, and 100% of ad libitum energy intake. Body mass measurements and baseline plasma samples were taken on a weekly basis after beginning of the treatment. After 3 weeks of treatment, chicks were exposed to a standardized acute handling and restraint stress protocol, where in addition to a baseline sample, three plasma samples were taken at intervals up to 50 min. We found that food-restricted chicks had lower body mass, chronically (during 2-3 weeks) elevated baseline and higher acute stress-induced levels of corticosterone compared to chicks fed ad libitum. Low lipid content of food further exacerbated these effects. An increase in baseline levels of corticosterone was observed within a week after energy requirements of food-restricted chicks exceeded their daily energy intake. A tendency for suppression of adrenocortical activity was observed in treatments fed low-lipid diets only at the end of the experiment. We suggest that nest-bound chicks, if food-stressed, might suffer deleterious effects of chronic elevation of corticosterone.  相似文献   
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