Effect of diisopropanolamine upon choline uptake and phospholipid synthesis in Chinese hamster ovary cells.

Aminoalcohols differ in mammalian toxicity at least in part based upon their ability to alter the metabolism of phospholipids and to cause depletion of the essential nutrient choline in animals. This study examined the incorporation of diisopropanolamine (DIPA) into phospholipids (PLs) and effects of DIPA upon choline uptake and phospholipid synthesis in Chinese hamster ovary (CHO) cells. Results were compared to those of a related secondary alcohol amine, diethanolamine (DEA), whose systemic toxicity is closely associated with its metabolic incorporation into PLs and depletion of choline pools. DIPA caused a dose-related inhibition of (3)H-choline uptake by CHO cells that was approximately 3-4 fold less potent, based upon an IC50, than that reported for DEA. DIPA, in contrast to DEA, did not cause changes in the synthesis rates of (33)P-phosphatidylethanolamine, (33)P-phosphatidylcholine or (33)P-sphingomyelin at either non-toxic or moderately toxic concentrations. Only approximately 0.004%, of administered (14)C-DIPA was metabolically incorporated into PLs, over 30-fold less than the incorporation of (14)C-DEA under similar conditions. Overall, these data and previous pharmacokinetic and toxicity data obtained in vivo suggests that DIPA is distinct from DEA and lacks significant choline and PL metabolism related toxicity in animals.     

吸莫合烟对金黄色地鼠肺组织超微结构的影响

目的 观察吸莫合烟对金黄色地鼠肺组织超微结构的影响。方法 取肺组织做超薄切片，用透射电镜观察。结果 Ⅰ型肺泡细胞和毛细血管内皮细胞均肿胀，线粒体亦肿胀，嵴排列紊乱，断裂消失；Ⅱ型肺泡细胞线粒体体积缩小，板层小体空泡变，胞膜破裂，细胞器溢出。泡巨噬细胞次级溶酶体明显增多。结论吸莫合烟可造成金黄色地鼠肺组织结构的改变，进而影响气体交换的功能。     

Exposure to ethanol during capacitation impairs the fertilizing ability of human spermatozoa in vitro

To validate earlier findings, mainly in laboratory animals, the effect of ethanol on the fertilizing ability of human spermatozoa has been investigated. Ethanol added to the capacitation medium reduced the penetration of zona-free hamster eggs by human spermatozoa in a dose-dependent manner at concentrations from 50 to 500 mg % (0.05-0.5%). Fertilizing capacity was at least partially restored by washing in ethanol-free medium. Ethanol exposure before capacitation had a slight stimulatory effect on the penetration of spermatozoa into zona-free hamster ova. The motility of spermatozoa was not altered significantly, either quantitatively or qualitatively, by the presence of ethanol in the capacitation medium. These results suggest that the decrease in fertilizing ability of spermatozoa induced by ethanol during capacitation is due to a specific action on the capacitation process.     

鱼露致中国仓鼠卵巢细胞HGPRT位点突变作用

背景与目的:研究鱼露及亚硝化鱼露对中国仓鼠卵巢(CHO)细胞HGPRT位点突变的影响.材料与方法:分别将鱼露和亚硝化鱼露分成4个不同剂量处理组:5 μl/ml、2.5μl/ml、1.25 μl/ml、0.625 μl/ml,另设阳性对照组(EMS:0.75 μg/ml,不需代谢活化;MCA:4 μg/ml,需代谢活化)和溶剂对照组(三蒸水),应用CHO/HGPRT基因突变试验,采用琼脂平皿法,检测鱼露和亚硝化鱼露对CHO细胞的毒性及突变体频率,评价鱼露及亚硝化鱼露引起突变的可能性.结果:经S9系统活化和未经S9系统活化的所有处理组突变体频率差异均有统计学意义(X2S9-=41.115;FS9 =19.528;P均＜0.01);亚硝化鱼露及经S9系统代谢活化后的鱼露组处理突变体频率均显著高于溶剂对照组(P＜0.05或P＜0.01),且存在剂量-效应关系(S9-:r 亚硝化鱼露=0.986,P＜0.05;S9 :r鱼露=0.950,P=0.05;r亚硝化鱼露=0.997,P＜0.01);而未经S9系统活化的鱼露处理组与溶剂对照组间差异均无统计学意义(P＞0.05).结论:鱼露经亚硝化后对CHO/HGPRT位点有致突变作用,经S9系统活化后可能也有此作用.     

中国仓鼠V79细胞系的oua~R和oua~S细胞蛋白质组分的双向电泳比较

作者用聚丙烯酰胺凝胶双向电泳,对中国仓鼠V79细胞系的乌本苷抗性突变型(oua~R)和野生型(oua~S)细胞的蛋白质组分进行比较,选择20个高度重复、分布均匀的肽斑作为参考标记,发现一些多肽在其位置、大小及密度上表现出差异,值得注意的是4小区(pI/MW为5.0/28～30kd)和6小区(pI/MW为6.3/39kd)的变化明显,提示这些多肽可能对V79细胞的oua~R是特异的,也许可作为oua~R细胞的特征性遗传标记。     

ON and OFF components of the receptive fields have different latencies to diffuse flashes of light in the superior colliculus of golden hamsters

Single unit activities were recorded from the superior colliculus in anesthetized hamsters. ON center and OFF center cells without surround showed short (within 150 ms) and long latency (longer than 150 ms) responses to diffuse flashes of light, respectively; ON and OFF center cells with an antagonistic surround and ON-OFF center cells showed both short and long latency responses. We suggest that the short latency discharges represent the activity on the ON component of the receptive field, while the long latency responses correspond to the OFF component. Thus, latencies of unit response to diffuse flashes of light may provide a useful indication of the existence of ON or OFF components in the receptive field.     

The Influence of Photoperiod on the Hypothalamic Content of Beta-Endorphin and the Luteinizing Hormone Responses to Naloxone and to Steroid Withdrawal in the Male Syrian Hamster

The aim of this study was to investigate the influence of inhibitory photoperiods upon opioidergic function, as determined by changes in the hypothalamic content of β-endorphin and the luteinizing hormone response to opioidergic receptor blockade, in the male Syrian hamster over the course of gonadal involution and spontaneous gonadal recrudescence. Animals exposed to an 8 h light: 16 h dark cycle (8L: 16D) for 14 weeks underwent gonadal regression. Regression was also observed in animals held for 7 weeks on one of a range of short daylengths of between 11.5 h and 13.5 h, the degree of atrophy being greatest in those animals on the shortest daylength. The tissue concentration of β-endorphin within the mediobasal hypothalamus was significantly higher in animals exposed to 8L: 16D for 14 weeks than in gonadally active controls held on long days (16L: 8D). Exposure to photoperiods of less than 13.5 h for 7 weeks also caused a significant increase in the β-endorphin content of the mediobasal hypothalamus and there was a positive correlation between the concentration of β-endorphin, the degree of gonadal atrophy and the shortness of the photoperiod. Endorphin levels within the preoptic area were not affected by photoperiodic treatments. Exposure of intact animals to 8L: 16D for 12 weeks caused gonadal atrophy and an associated loss of the luteinizing hormone responses to both naloxone and castration. Castrated animals receiving testosterone replacement (cast + T) also exhibited photoinhibition, in the form of reduced serum levels of luteinizing hormone, and this was similarly accompanied by a loss of sensitivity to naloxone and to withdrawal of steroid. Prolonged exposure to 8L:16D led to spontaneous reactivation of the gonadotrophic axis as a consequence of the development of scotorefractoriness. In both gondally intact animals and in cast + T groups, this was associated with a restoration, in parallel, of the luteinizing hormone responses to naloxone and to castration/ steroid withdrawal. The time-course of the restoration of the response to steroid withdrawal in castrates was not significantly different to that observed in intact animals. The luteinizing hormone response to naloxone took significantly longer to redevelop in cast + T groups than it did in gonadally intact animals. The data demonstrate that central opioid systems are sensitive to photoperiod and are consistent with the hypothesis that opioids are involved in the neuroendocrine regulation of reproductive responses to daylength.     

Testicular function in eight patients with seminoma after unilateral orchidectomy and radiotherapy

Testicular function was monitored in eight patients with low stage seminoma who were treated with radiotherapy following unilateral orchidectomy. The absorbed gonadal radiation dose ranged from 15 to 157.5 rad. At 10-24 months after radiotherapy, serum hormone levels, sperm analysis, sperm penetration into zona-free hamster ova (HOP-test) and lymphocyte chromosome abnormalities were evaluated. Two patients were azoospermic with elevated serum levels of LH and FSH. The remaining six patients had slightly decreased (n = 3) or normal (n = 3) seminal parameters. Their HOP rates were within the normal range. A low incidence of polyspermy (i.e. only one penetrating sperm per ovum) was found in the patients, suggesting low penetrability of motile sperm. A highly significant correlation was found between sperm count or sperm penetrability and time post-irradiation. The results indicate that restitution of testicular function is time-dependent.     

Plasma membrane potential of lymphocytes from ataxia telangiectasia patients

The plasma membrane potential of lymphocytes prepared from ataxia telangiectasia (AT) patients and normal subjects was assessed using the optical indicator bis-(3-phenyl-5-oxoisoxazol-4-yl) pentamethineoxonol (oxonol-V). AT lymphocytes had a potential of -46 +/- 9 mV and normal lymphocytes had a potential of -63 +/- 4 mV. The intracellular cation content (Na+ and K+) of AT and normal lymphocytes was similar. AT and normal lymphocytes were both depolarized by extracellular K+ and to a similar extent. This study indicates that one feature characterizing ataxia telangiectasia is a modification of the ability of the lymphocyte cell membrane to sustain a normal membrane potential.