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。     

Metabolic alkalosis after pediatric cardiac surgery.

OBJECTIVE: To determine occurrence, causes and associated mortality of postoperative metabolic alkalosis in pediatric cardiac surgery. METHODS: We retrospectively analyzed clinical and biochemical variables of 186 consecutive cardiac operations other than ductal ligations on children less than 2 years old during the years 1999 and 2000. Metabolic alkalosis was defined as a pH>7.48 corrected for PCO2, with a base excess > or =5 on two or more consecutive measurements during an 8h period. RESULTS: Median age was 15 weeks [range 2 days-95 weeks] and median weight 4.5 kg [range 2.1-15.7 kg]. In 157 cases, cardiopulmonary bypass was used. In 92 [49%] procedures, metabolic alkalosis occurred with the highest corrected pH 24.3h after operation. Multivariate regression analysis associated age [P<0.001], cardiopulmonary bypass [P<0.001] and preoperative ductal dependency [P=0.04] with postoperative metabolic alkalosis. Of the surgical procedures the arterial switch for transposition of the great arteries [n=19] was strongly associated with metabolic alkalosis [100%, P<0.001]. Hemodilution appeared to enhance the development of alkalosis: those who experienced alkalosis had been hemodiluted to a greater extent [P=0.007]. Nearly 95% of patients experienced some increase in bicarbonate, but patients with metabolic alkalosis experienced more than those without [5.9 versus 3.5 mmol/l, P<0.001]. There were four postoperative deaths, only one coincidental with metabolic alkalosis. CONCLUSIONS: Metabolic alkalosis has a high incidence after pediatric cardiac surgery, strongly associated with younger age, cardiopulmonary bypass, preoperative ductal dependency and perioperative hemodilution. Early recognition allows for timely therapeutic intervention.