Neutrophil Oxygen Radical Production by Dialysis Membranes

The ability of different dialysis membranes to activate polymorphonuclearneutrophil oxygen radical production was investigated with chemiluminescence.All the six membranes, namely cuprophan, cellulose acetate,polycarbonate, polysulphone, polyacrilonitrile and polymethylmethacrylatewere able to interact with neutrophils and stimulate their oxygenradical production, the highest responses being seen with polyacrilonitrile,polymethylmethacrylate and polycarbonate. To analyse the roleof complement in this interaction, fresh plasma, heat inactivatedand zymosan-activated plasma were added: with fresh plasma oxygenradical production was stimulated on cuprophan, cellulose acetateand polysulphone, not modified on polycarbonate, and decreasedon polyacrilonitrile and polymethylmethacrylate. With heat-inactivatedplasma, the responses were decreased or abrogated on all themembranes except polycarbonate and polymethylmethacrylate, whereaswith zymosanactivated plasma similar responses to fresh plasmawere observed. In addition, when plasma was used to precoatthe membrane, cuprophan, cellulose acetate and polysulphonedisclosed an enhanced neutrophil oxidative burst, while precoatedpolyacrilonitrile and polymethylmethacrylate were less stimulatorythan uncoated membranes. In contrast the precoating of polycarbonatedid not modify oxygen radical production. These data suggestthat neutrophil activation occurs by direct membrane neutrophilinteraction. Plasmatic factors modulate this interaction butcomplement seems involved on cellulosic and polysulphone membranesonly. Therefore, it appears that oxygen radicals produced fromcontact of neutrophils with the dialysis membrane might playan initial and/or additional role in the events occurring atthe initiation of haemodialysis.     

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。