荧光原位杂交技术分析人结肠菌群方法研究

建立荧光原位杂交技术分析人体内结肠菌群的方法。取受试者新鲜粪便 ,选用 5种特异性的 16SrRNA寡核苷酸探针 ,检测粪便样本收集后的保存时间、温度 ,离心条件及样本固定液存放时间对杂交计数结果的影响。结果建立最佳实验条件为 :粪便样本收集后应尽快在 4℃下保存 ,放置时间不要超过 12小时即作处理 ;样本的适宜离心条件为 70 0g 2分钟 ;样本用多聚甲醛固定后在 - 80℃下存放时间不要超过 5个月。该方法具有较好的稳定性 ,可以有效地检出个体之间结肠菌群的差异。     

Anatomical and behavioral sequelae of fetal brain transplants in rats with trimethyltin-induced neurodegeneration.

The effect of transplants of either fetal hippocampal or dorsal ventricular ridge (DVR) tissue into the brains of adult male rats exposed to TMT was determined for two behavioral tasks. Administration of TMT produced deficits in acquisition and performance of an operant differential reinforcement of low response rates (DRL) schedule and learning in the Morris water maze. The fetal transplants developed well within the TMT-damaged brains of the adult rats and numerous axons could be shown to cross the host-transplant interface. The transplants significantly reduced the DRL deficit produced by exposure to TMT. However, the TMT-induced deficit in water maze acquisition was made significantly worse by the hippocampal transplants. The improvement in DRL performance is attributed to the effect on the host brain of an unidentified trophic substance produced by the transplants. However, this positive effect may not protect the brain sufficiently to produce recovery in tasks demanding more complex neural computations than are required to withhold lever-press responses. The transplant-induced deficit observed in some aspects of water maze acquisition and performance may be attributable to either a tumor-like deleterious effect of the mass of the transplant or to abnormal neuronal activity transmitted from the transplant to the host brain. The results of the present study, and those from other similar studies, suggest that transplants of fetal tissue may be useful in producing changes in the brain of an animal exposed to an environmental neurotoxin, but that research should be focused upon development of transplant methodology that will minimize adverse effects of the grafts.