Neuronal Gonadotrophin‐Releasing Hormone (GnRH) and Astrocytic Gonadotrophin Inhibitory Hormone (GnIH) Immunoreactivity in the Adult Rat Hippocampus

Gonadotrophin‐releasing hormone (GnRH) and gonadotrophin inhibitory hormone (GnIH) are neuropeptides secreted by the hypothalamus that regulate reproduction. GnRH receptors are not only present in the anterior pituitary, but also are abundantly expressed in the hippocampus of rats, suggesting that GnRH regulates hippocampal function. GnIH inhibits pituitary gonadotrophin secretion and is also expressed in the hippocampus of a songbird; its role outside of the reproductive axis is not well established. In the present study, we employed immunohistochemistry to examine three forms of GnRH [mammalian GnRH‐I (mGnRH‐I), chicken GnRH‐II (cGnRH‐II) and lamprey GnRH‐III (lGnRH‐III)] and GnIH in the adult rat hippocampus. No mGnRH‐I and cGnRH‐II+ cell bodies were present in the hippocampus. Sparse mGnRH‐I and cGnRH‐II+ fibres were present within the CA1 and CA3 fields of the hippocampus, along the hippocampal fissure, and within the hilus of the dentate gyrus. No lGnRH‐III was present in the rodent hippocampus. GnIH‐immunoreactivity was present in the hippocampus in cell bodies that resembled astrocytes. Males had more GnIH+ cells in the hilus of the dentate gyrus than females. To confirm the GnIH+ cell body phenotype, we performed double‐label immunofluorescence against GnIH, glial fibrillary acidic protein (GFAP) and NeuN. Immunofluorescence revealed that all GnIH+ cell bodies in the hippocampus also contained GFAP, a marker of astrocytes. Taken together, these data suggest that GnRH does not reach GnRH receptors in the rat hippocampus primarily via synaptic release. By contrast, GnIH might be synthesised locally in the rat hippocampus by astrocytes. These data shed light on the sites of action and possible functions of GnRH and GnIH outside of the hypothalamic‐pituitary‐gonadal axis.     

Lysozyme Activity in the Plasma of Rodents Infected With Their Homologous Trypanosomes

Background

In this study the concentration of lysozyme in blood plasma of Microtus agrestis, Clethrinomys glareolus, Apodemus sylvaticus, BK rats and outbred white mice before and after infection with culture forms of Trypanosoma microti, T, evotomys, T. grosi, T. lewisi and T. musculi respectively was measured.

Methods

Blood samples of rodents, Microtus agrestis, Clethrionomys glareolus, Apodemus sylvaticus, BK rats and outbred mice infected with T. microti, T. evotomys, T. grosi, T. lewisi and T. musculi respectively were collected in heparinized micro- tubes immediately before inoculation and 3, 6, 12, 24, 48, 96 and more than 400 days after intra- perituneal inoculation with 5×10⁵of their homologous trypanosome parasites of which more than half were metacyclic trypomastigote in 0.2 ml of culture medium. Micro- tubes were centrifuged and plasma samples were separated and the lysozyme activity was measured by the agar method.

Results

Levels of lysozyme rose rapidly three to six days after the inoculation to ten to twenty than their pre- infection levels. They then gradually decreased, although after more than one year they were still two to ten folds higher than controls. The highest level measured occurred in rats infected with T. lewisi and the lowest in A. sylvaticus infected with T. grosi. After one year the highest concentration of lysozyme was in mice infected with T. musculi and lowest in A. sylvaticus.

Conclusion

Persistent enhanced lysozyme levels may prevent re- infection with trypanosomes.     

静脉药瘾者人类免疫缺陷病毒核酸测定及亚型分析

目的：了解静脉药瘾者人类免疫缺陷病毒（HIV）感染情况及感染亚型，追踪传染源，预测未来流行株。方法：对1997年从新疆至杭州的15例静脉药瘾者血清进行抗－HIV的初步筛选，结果为阳性者再行免疫印迹（Western blot)、套式聚合酶链反应（Nest-PCR)及HIV核酸序列分析，结果：15例新疆籍静脉药者均感染了HIV－1，其中有2例E亚型，其余均为C亚型。结论：静脉吸毒者主要感染HIV－1C亚型，我国HIV－1主要流行株可能已经发生变化。     

Fetal erythropoiesis in steel mutant mice. III. Defect in differentiation from BFU-E to CFU-E during early development

Erythroid progenitor cells in +/+ and Sl/Sld fetal livers manifested as burst-forming units-erythroid (BFU-E) and colony-forming units- erythroid (CFU-E) were assayed in vitro during early development. The proportion of BFU-E was higher as mutant than in normal fetal livers. On the other hand, the proportion of CFU-E was less in the mutant than in the normal. These results suggest that the defect in Sl/Sld fetal hepatic erythropoiesis is expressed at the steps of differentiation that effect the transition from BFU-E to CFU-E.     

Prevalence and predictors of Toxoplasma seropositivity in women with and at risk for human immunodeficiency virus infection

We assessed the prevalence and predictors of latent Toxoplasma infection in a large group of human immunodeficiency virus (HIV)-infected and HIV-uninfected at-risk US women. The prevalence of latent Toxoplasma infection was 15% (380 of 2525 persons) and did not differ by HIV infection status. HIV-infected women aged > or =50 years and those born outside of the United States were more likely to have latent Toxoplasma infection, with prevalences of 32% and 41%, respectively.     

种植牙——人类的第三副牙齿

研究显示,若全口无牙,人的全身机能将下降40％～60％,佩戴假牙之后,全身机能也只能恢复到正常的81％-95％．种植牙的诞生为彻底解决缺牙带给患者咀嚼功能和语言发音障碍,影响面容美观和心理伤害等长期困扰其健康和生活质量问题提供了一个重要出路．伴随技术的成熟,种植牙也因此被誉为继乳牙、恒牙之后,人类的第三副牙齿．它是生命科学和材料与工程科学完美结合所诞生的产物,是近半个世纪以来口腔医学献给人类健康的一份厚礼．种植牙作为天然牙齿的替代体,人工牙根可以和牙床完全融合,