硒的人体最大安全摄入量研究 三、恩施高硒点居民血和发中某些拮抗金属元素的含量

恩施高硒区的硒来源于煤.煤中除硒外,尚有高含量的氟.此外,本地尚分布有丰富的硫铁矿,居民用作生产硫磺.由于环境污染严重,因此在观察硒的毒性时,应考虑其它有关元素的含量.本文测定了居民发中的Cd,Hg,As以及全血中的Cd,Zn和Cu等元素.从组织和血中这些元素的含量来考虑,唯有Cd对硒中毒的影响值得注意.     

Vasopressin receptors in the mouse (Mus musculus) brain: sex-related expression in the medial preoptic area and hypothalamus

We have investigated the distribution of vasopressin binding sites in the brain of male and female adult mice using a radio-iodinated ligand and film autoradiography. Vasopressin receptors were uncovered in various regions of the brain including the basal nucleus of Meynert, the substantia innominata, the hypothalamic paraventricular nucleus, the substantia nigra pars compacta and the hypoglossal nucleus. A sex-related difference in the expression of vasopressin receptors was seen in the medial preoptic area/anterior hypothalamus corresponding to the rat sexually dimorphic nucleus in the rat and in the hypothalamic mammillary nuclei. In both structures the autoradiographic labeling is more intense in females than in males. These observations confirm that vasopressin binding sites are present in the hypothalamic preoptic area of most species examined so far and that sex-related expression of neuropeptide receptors could trigger sex-related behavioral differences.     

Motor unit potential contribution to surface electromyography

The background of the bioelectric activity of muscle recorded from the surface of the skin (surface electromyography) in terms of the representation of single motor units of the underlying muscle(s) is not very well documented or understood. An insight into the composition of an electromyogram is essential for the proper interpretation of one of the most widely applied electrophysiological techniques. In the present paper, a study of the contribution of single motor unit potentials to the surface electromyogram is presented. To this end, the decline of different components of the motor unit potential with depth of the motor unit is quantified. Experimentally, the action potentials from motor units at several positions in the muscle were recorded by 30 skin surface electrodes. Simultaneous use of scanning electromyography provided information about the actual position and size of the motor unit. Observed linear log–log relationships between motor unit potential magnitudes and distance indicated the usefulness of a power function to describe the motor unit potential's dependence on recording distance. It is shown that different specific surface motor unit potential characteristics fall off differently with depth. The magnitude–distance relationship is shown to be dependent on the recording configuration (unipolar vs. bipolar recording, including the inter-electrode distance) and the chosen motor unit potential parameter (negative peak amplitude, positive peak amplitude and area).     

Analysis of the Inhibitory Effect of Oestradiol on Functional GABA/5-HT Relationship in the Rat Suprachiasmatic Area

The purpose of this study was to test the capacity of oestradiol to modulate the stimulating effect of a-aminobutyric acid (GABA) on serotonin (5-HT) metabolism, previously described in the Suprachiasmatic area of the male rat. After an in vivo stimulation of GABA transmission by systemic administration of a GABA-transaminase inhibitor (amino-oxyacetic acid) or a GABA_B agonist (RS-baclofen), the 5-HT metabolism was studied in the Suprachiasmatic area of ovariectomized, and ovariectomized oestradiol-treated rats. Amino-oxyacetic acid or RS-baclofen treatment increased the endogenous content of 5-HT in the Suprachiasmatic area of males and ovariectomized rats. These two treatments were without effect in ovariectomized oestradiol-treated rats. GABA transmission stimulation induced by amino-oxyacetic acid treatment failed to affect the release and synthesis of 5-HT in ovariectomized oestradiol-treated rats while it increased these two parameters of 5-HT metabolism in the Suprachiasmatic area of male and ovariectomized rats. To investigate the main target of oestradiol effect, comparative studies of the serotoninergic and GABAergic metabolism in the Suprachiasmatic area were performed in the three experimental groups. Under our experimental conditions the endogenous 5-HT metabolism was similar between ovariectomized and ovariectomized oestradiol-treated rats. Nevertheless, 5-HT metabolism was higher in the two female groups than in the male group. Neither GABA metabolism nor GABAergic response to GABA-related drug treatment differed between ovariectomized, and ovariectomized oestradiol-treated rats. However, the turnover of GABA was higher when compared to the two female groups. It is concluded that the lack of 5-HT responsiveness to GABA transmission stimulation in ovariectomized oestradiol-treated rats was not related to an effect of oestradiol on 5-HT metabolism or to an effect of the steroid on GABA turnover. Furthermore, our results suggest a sex difference in the activity of serotoninergic and GABAergic systems in the Suprachiasmatic area.     

Down-Regulation of Estrogen Receptor Immunoreactivity by 17β-estradiol in the Guinea Pig Forebrain

Low amplitude pulses of estradiol-17β (E₂-17β) are more effective than large single bolus injections or constant exposure to E₂-17β in inducing progesterone-facilitated sex behavior in female rats and guinea pigs. The present study examined whether the increased responsiveness to E₂-17β is due to an increase in the number of estrogen receptors in the estrogen receptor rich areas of the hypothalamus and amygdala. Initial studies examined the rapid effects (20 min) of a high dose of E₂-17β (50 μg) on estrogen receptor immunostaining using either the H222 antibody or the ER 21 antiserum. ER 21 immunostaining was not affected by the E₂-17β treatment suggesting that it binds to both occupied and unoccupied estrogen receptors. Therefore the ER 21 antiserum was used to characterize the regulation of estrogen receptor immunoreactivity (ER-IR) by E₂-17β. ER-IR was examined for 48 h and serum E₂-17β for 24 h following a 2 μg s.c. injection of E₂-17β (a dose similar to that used in multiple pulse paradigms). Serum E₂-17β peaked 15 to 30 min following the injection and returned to baseline values by 1 h. In all but one area maximal suppression of ER-IR occurred at 12 h. In summary, 1) decreases in estrogen receptor immunoreactivity following E₂-17β are consistent with studies in which estrogen receptors were assayed by binding assays and estrogen receptor mRNA was determined by in situ hybridization; 2) the ER 21 antiserum is able to detect both occupied and unoccupied estrogen receptors and 3) H222 immunoreactivity is influenced by the presence of E₂-17β, so that the level of H222-IR is a reflection of ligand/receptor binding dynamics. The data suggest that up-regulation of estrogen receptors does not account for the increase in behavioral sensitivity which is observed following multiple pulses of E₂-17β.     

鞍区肿瘤术后中枢性低钠血症的诊断和治疗

目的:探讨鞍区肿瘤术后中枢性低钠血症的诊断及处理方法。方法:对我科近四年鞍区肿瘤术后并发中枢性低钠血症的58例患者进行回顾性分析,术前、手术当日及术后每日定时检测血钠,观察尿量变化,测定中心静脉压,确定低钠血症的类型并给予相应的处理。结果:56例恢复正常,1例死于严重肺部感染,1例自动出院。结论:鞍区肿瘤易出现抗利尿激素分泌不当综合症和脑性耗盐综合症两种类型。前者需限水治疗,后者应予以充分补钠、补水,根据水、钠检测水平治疗。     

大鼠癫痫持续状态黑质－腹侧被盖区多巴胺的组织化学研究

本实验用荧光组化技术及记录显微自动曝光时间方法研究了马桑内酯所致的Ｗｉｓｔａｒ大鼠癫痫持续状态黑质－腹侧被盖区多巴胺含量的变化。结果显示癫痫发作高峰组（１０只）和发作后组（８只）该区多巴胺含量明显低于对照组（１０只）和发作前组（１０只）。由于多巴胺是一种抑制性神经递质，它的减少可能表明抑制作用的下降对癫痫的发作有一定的调控作用。     

内蒙古啮齿动物分布聚类区初步探讨

本文将内蒙古５５种啮齿动物在本自治区８个动物地理省中的有或无分布作为二元属性，表征动物地理省间种类组成的相似性用联合系数表示，并以类平均法进行聚类。根据聚类结果，讨论了分布聚类与动物地理区划的关系。     

Nasal septum lesions caused by chromium exposure among chromium electroplating workers

A chromium electroplating worker, suffering from epistaxis during work, was found to have nasal septum perforation. To determine the etiology and prevalence of nasal septum lesions, we conducted a survey of seven chromium electroplating factories and examined 79 workers. Forty workers from three aluminum electroplating factories were also enrolled as the reference group. Subjects were thoroughly examined by an otolaryngologist and each of them provided a blood and urine sample. A questionnaire interview regarding symptoms of the upper respiratory tract, past medical history, life style, and work history was also conducted. Air chromium concentrations were measured by taking area samples for 4–6 hours. Based on field observation and chromium measurements, we divided chromium electroplating into three different exposure zones: workers directly dealing with electroplating tanks (n = 31), other process workers (n = 29), and office workers and drivers (n = 19). Among the 79 chromium electroplating workers, there were 16 cases of nasal septum perforation, and 42 with either scar formation or ulceration; 10 chromium electroplating workers developed skin ulcers after performing chrome plating. No workers from aluminum electroplating factories had any nasal septum or skin abnormalities. There was a consistent trend between the degree of chromium exposure and the signs and symptoms related to the nose, throat, and skin. Immediate improvement of occupational hygiene is warranted.     

大肠癌高发区嘉善县大肠癌危险因子的调查研究

在大肠癌高发区嘉善县进行了病例对照调查,以探索大肠癌的致癌危险因子。病例160名(结肠癌61名,直肠癌99名),对照320名。调查询问项目分食物项目和非食物项目。计算结果表明,在非食物方面,RR数值达到显著水平的有:肠息肉、腹泻、粘液血便、精神刺激、阑尾炎、阑尾切除和家族肿瘤史等;在食物方法,对照组比病例组摄入的粗纤维和维生素C的量多,且达到显著水平。