Leishmania species: Comparative ultrastructure of experimental nodules and diffuse human cutaneous lesions in American leishmaniases

Experimental nodules of American leishmaniases were obtained by inoculating 0.1–1 × 10⁵ amastigotes into the dorsum of the hindpaws of golden hamsters and of C57B1/6J mice. The amastigotes were obtained by biopsy of lesions in six human cases of cutaneous leishmaniases and were serially maintained in golden hamsters and in a fetal calf serum-containing medium. Human nodules were obtained by biopsy from several patients with diffuse cutaneous leishmaniases, always prior to treatment. Within the same host species, no ultrastructural differences were seen in the tissue response to isolates of Leishmania mexicana, L. brasiliensis, or L. garnhami, nor were there differences between the host species in response to a particular isolate of the genus Leishmania. The typical inflammatory response was a macrophage granuloma with abundant polymorphonuclear neutrophils, some eosinophils, and plasma cells. Simple human cutaneous leishmanial lesions, as well as experimental nodules in regression, show many fibroblasts, much collagen fiber, but very few parasites. In typical lesions, parasites occurred within macrophage phagolysosomes, within distended lacunar cells, and in the intercellular spaces. Leishmaniae strongly adhered to parasitophorous vacuoles by a site of their plasma membrane directly opposite the flagellum, and the host cell cytoplasm close to the adherence site became highly vacuolated. In most cases the intra- and extracellular parasites show normal morphology, which suggest the inability of phagocytic cells to attack them.     

电刺激兔尾核对丘脑束旁核神经元痛放电的影响

实验在75只家兔上进行。以玻璃微电极记录丘脑束旁核痛放电,以电脉冲(5次/s、0.2ms、8—10V)通过双极同心电极刺激尾核头部,结果表明刺激尾核对束旁核痛放电既产生抑制效应(34/38),也产生易化效应(4/38)。抑制有两种表现方式:1.改变诱发放电的型式,2.跟随着单个刺激脉冲出现对痛放电的短暂压抑。静脉注射纳洛酮或阿托品可以阻断尾核刺激所引起的第一种抑制效应,提示尾核内阿片肽能系统和胆碱能系统活动参与对束旁核痛觉信号活动的调制。本文也观察到尾核刺激可诱发束旁核神经元出现每分钟约6次的周期性锋形电位串。     

我国实验常用豚鼠 Cavia Porcellus 内膝体的定位

按常规方法将豚鼠固定于立体定位仪架上,用插电极、通电烧灼及亚铁氰化钾甲醛溶液灌流固定的检查技术确定内膝体中心的座标值。结果表明,300—800g动物的内膝体前后座标值 A 及左右座标值 LR 有线性地随体重而增大的趋势,水平座标 H 值则变化较小。三组数据的线性方程为 A=0.0047W 3.9,LL或RL=0.0018W 3.7,H=-3.1。体重400—600g豚鼠的模座标值为 A=6.3,LL 或 RL=4.6,H=-3.1。当从电极引出的短声诱发电位主波为负相时通常提示记录点在该核团内,这可作为进行活体实验时有用的定位辅助指标。     

Localization of GRF-like immunoreactive neurons in the rat brain

The localization of human GRF1-44-immunoreactive neurons was studied in the rat brain. A dense accumulation of GRF-containing fibers was noted in the external layer of the median eminence. Cell bodies were observed in colchicine-treated rats. The most intensely fluorescent cluster of cells was contained in the arcuate nucleus. Other cells were seen on the base of the hypothalamus, within the median forebrain bundle, dorsal and ventral aspects of the ventromedial nucleus, zona incerta and dorsal part of the dorsomedial nucleus. These cells may influence the pulsatile release of pituitary growth hormone.     

Different effects of chronic Na+, Cl−, and K+ depletion on brain vasopressin mRNA and plasma vasopressin in young rats

1. We studied the effects of selective chronic dietary sodium, chloride, or potassium depletion in young rats on vasopressin mRNA levels in the supraoptic and paraventricular nuclei, an index of vasopressin formation, and in plasma vasopressin levels, an index of vasopressin release. 2. All diets significantly increased plasma renin activity, contracted the extracellular fluid volume, and decreased serum osmolarity. 3. In the supraoptic nucleus, vasopressin mRNA levels were significantly decreased in the low-sodium group but were not significantly affected by chloride depletion. 4. There were no significant changes in vasopressin mRNA in the paraventricular nucleus after sodium or chloride dietary depletion. 5. After 2 weeks of potassium depletion, vasopressin mRNA levels were decreased in the supraoptic nucleus. When potassium depletion was prolonged for 3 weeks, vasopressin mRNA levels increased in both supraoptic and paraventricular nuclei. 6. Plasma vasopressin levels were high in animals subjected to dietary chloride depletion or to 3 weeks of potassium depletion. Dietary sodium depletion or 2 weeks of dietary potassium depletion did not significantly affect plasma vasopressin. 7. Our results show that chronic sodium, chloride, or potassium depletion differentially affect brain vasopressin mRNA and vasopressin release in young rats. 8. The effect of these diets may be mediated through changes in the extracellular fluid volume, serum osmolarity, and/or renin angiotensin system.     

Efferent projections from the lateral geniculate nucleus to the pineal complex of the Mongolian gerbil (Meriones unguiculatus)

Summary The intergeniculate leaflet of the lateral geniculate nucleus is considered to modulate circadian activity rhythms probably mediated by a direct neuronal connection to the suprachiasmatic nucleus. The present study in the gerbil demonstrates, by anterograde tracing with Phaseolus vulgaris-leucoagglutinin (PHA-L), the existence of an additional neuronal projection from a subportion of the lateral geniculate nucleus, involving the intergeniculate leaflet, directly to the pineal gland. PHA-L-immunoreactive nerve fibers originating from perikarya at the injection site were located under the optic tract projecting towards the midsagittal plane. Delicate PHA-L-immunoreactive nerve fibers were observed in the posterior paraventricular thalamic nucleus, precommissural nucleus, olivary pretectal nucleus, anterior and posterior pretectal nuclei, and posterior commissure. Single fibers could be followed from the caudal part of the medial habenular nucleus and the pretectal area into the rostral part of the deep pineal gland. Other fibers continued through the posterior commissure into the contralateral hemisphere to terminate in the same structures as on the ipsilateral side. From the posterior commissure, small bundles of thick fibers entered the deep pineal gland where they arborized among the endocrine cells. A few nerve fibers were observed in the habenular commissure and the pineal stalk, but no fibers were identified in the superficial pineal. This direct geniculo-pineal connection suggests that the pineal gland is directly influenced by the optic system.     

大鼠前庭内侧核在前庭—交感反应中的作用

实验在氯醛糖和尿酯混合麻醉的大鼠上进行。在内脏大神经上记录刺激同侧前庭神经进入脑干处的交感反应。电刺激前庭神经可在同侧内脏大神经引出—明确的叠加反应,其平均潜伏期为45.8±6.98ms,时程为55.21±5.35ms。增加刺激强度,反应幅度也增加,但潜伏期不变。用前庭内侧核(NVM)的片层场电位作为指标并选择其相位倒转处作刺激点,可在同侧内脏大神经记录到潜伏期为32ms 的叠加反应,而同一动物刺激前庭神经入脑处时内脏大神经反应的潜伏期为43ms。在 NVM 头端损毁后,此前庭-交感反应明显减小,再损毁尾端 NVM 后,此反应消失。损毁 Deiters 核对前庭-交感反应无影响。这些结果表明 NVM在内脏大神经记录到的前庭-交感反应中是一重要的中继站。     

电刺激弓状核对胃内压的影响及其外周途径分析

选用 Wistar,大鼠68只,乌拉坦麻醉下观察了电刺激弓状核对胃内压的影响。结果为:电刺激弓状核,胃内压显著降低;这一作用被迷走神经切断或腹腔神经丛摘除而减弱;酚妥拉明也能减弱电刺激弓状核的这一作用,但阿托品和心得安对此均无影响;同时去除交感神经和迷走神经时,刺激弓状核的这一作用虽被减弱,但仍然存在。上述结果表明:(1)刺激弓状核降低胃内压的外周神经途径同时涉及交感神经和迷走神经;前者由α-受体介导,后者可能由其中的非胆碱能、非肾上腺素能纤维发挥作用;(2)体液因素可能参与刺激弓状核的这一作用。     

大鼠蓝斑核区神经降压素对迷走—加压反应的影响

本文应用放射免疫、核团微量注射及组织荧光分光测定等实验方法,研究大鼠蓝斑核区神经降压素对迷走-加压反应的影响。结果表明:1.电刺激颈迷走神经向中端,孤束核、蓝斑核区和下丘脑中神经降压素免疫活性物的含量明显增高(p<0.05)。2.蓝斑核区注入神经降压素后,刺激颈迷走神经向中端,迷走-加压反应明显减弱(P<0.01),并呈明显的量效依赖关系。3.蓝斑核区注入抗神经降压素血清,迷走-加压反应明显加强(p<0.01)。4.蓝斑核区注入神经降压素后,刺激颈迷走神经向中端,该区去甲肾上腺素含量明显增高(p<0.05)。以上结果提示:内源与外源性神经降压素参与迷走-加压反应的调节过程,并可能与神经降压素引起蓝斑核区去甲肾上腺素含量增加有关。