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In BALB/c mice, successful defense against visceral leishmaniasis is T cell dependent, expressed by tissue granuloma formation, and probably mediated by macrophages activated by cytokines, including gamma interferon (IFN-gamma). C57BL/6 ep/ep (pale ear) mice, which reportedly exhibit impaired IFN-gamma production, were challenged with Leishmania donovani to determine the outcome of infection in a euthymic host with an apparent defect in lymphokine secretion. In BALB/c and normal C57BL/6 mice, L. donovani liver burdens peaked at 2 weeks and were largely eliminated by 4 weeks. In contrast, in pale ear mice, infection progressed until after 4 weeks and persisted at high levels at 8 weeks. The failure to resolve hepatic infections was not related to deficiencies in (i) Thy-1+, L3T4+, or Lyt-2+ T cells; (ii) IFN-gamma secretion; (iii) liver tissue Ia expression; (iv) macrophage antimicrobial capacity; or (v) antileishmanial antibody production. However, despite the anticipated influx of mononuclear cells into livers, these cells were not properly focused on the parasitized Kupffer cells, the inflammatory infiltrate receded prematurely, and mature granulomas failed to develop. These results suggest that there is a cellular immune defect at the tissue level and emphasize the critical role of granuloma formation in successful resolution of systemic intracellular infections.  相似文献   
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Suicide by fire is relatively rare in the Western world, accounting for approximately 1% of completed suicides by all methods. This survey identified suicidal deaths among fatalities known to the Scottish Fire Brigades as having died in a fire incident during 1980 to 1990. It is accepted that this is just one possible definition of what constitutes a suicide by fire. Forty cases were identified as suicides from the circumstances of the death as narrated in the police and Fire Brigade reports of the incident. Autopsy and toxicological reports were examined for all cases and the characteristics of the victim and the incident are described. Most cases occurred in the home of the victim and three-quarters of the victims were pronounced dead at the scene or when first seen by a doctor. Smoke inhalation was the most frequently certified cause of death. Alcohol was present in less than half the cases and toxicological analysis for drugs was performed in the minority of cases. One-quarter of victims were reported to have made at least one suicide attempt previously. A range of apparently precipitating factors was observed: the number of cases which appeared to be impulsive responses to life events suggests that prevention is difficult.  相似文献   
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SQ 65,396, a clinically active anti-anxiety agent, enhanced the binding of 3H-diazepam at 1.5 nM. This effect was due to an increase in the affinity for the ligand, without a change in the number of 3H-diazepam binding sites. This action of SQ 65,396 may mediate its anti-anxiety effects by affecting the action of an endogenous modulator of the "benzodiazepine receptor." Several other substances and treatments increase the affinity of 3H-diazepam for its receptors by mechanisms which may be related to the effect produced by SQ 65,396.  相似文献   
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