灰毡毛忍冬化学成分研究V灰毡毛忍冬素F和G的结构测定

灰毡毛忍冬化学成分研究Ｖ灰毡毛忍冬素Ｆ和Ｇ的结构测定陈敏，吴威巍，沈国强，罗思齐，李惠庭（上海医药工业研究院２０００４０）灰毡毛忍冬（ＬｏｉｎｃｅｒａｍａｃｒａｎｔｈｏｉｄｅｓＨａｎｄ．－Ｍａｚｚ）系忍冬科忍冬属植物，别名大花忍冬，分布于贵州、广西、...     

Evaluation of a routine for prevention and treatment of fissure caries in permanent first molars

Fissure sealing as well as fluoride varnish have shown good preventive effect against fissure caries in newly erupted teeth. The purpose of this study was to evaluate a clinical routine in which these two methods were combined. The evaluation was done in a public dental clinic in Norway, and three dentists performed and evaluated the treatment. The population belonged to two different year classes (born 1978 and 1979), 196 in all, and they were followed semiannually from age 6 until 8 and 9 yr, respectively. The routine was as follows: all erupted permanent first molars without fissure caries were cleaned and painted with a fluoride varnish (Duraphat) every 6 months. Fissures showing incipient caries were opened with a rotating instrument and sealed if caries was restricted to the enamel. Amalgam fillings were placed if caries had progressed to the dentin. The operator time required for the fissure treatment was recorded. After 2 yr observation of children born in 1978 and 1979, 72% of the fissures were intact, 13% had been sealed, and 15% filled, and the corresponding figures after 3 yr (1978-children) were 65%, 15%, and 20%. In approximately 45% of the children all four permanent molars were intact, while about 12% had all molars sealed or filled. The average time spent for application of sealants was 4.1 min and for application of amalgam fillings 5.9 min.     

Activation of the CPP32 protease in apoptosis induced by 1-beta-D- arabinofuranosylcytosine and other DNA-damaging agents

The response of human myeloid leukemia cells to treatment with 1-beta- arabinofuranosylcytosine (ara-C) includes the induction of apoptosis. Ara-C induced apoptosis is associated with proteolytic cleavage of poly(ADP-ribose) polymerase (PARP) and protein kinase C (PKC) delta. However, the signals involved in this response are unknown. The present studies show that ara-C treatment of U-937 cells is associated with induction of a protease activity that cleaves the tetrapeptides Ac-DEVD- pNA and Ac-DMOD-pNA found at the cleavage sites of PARP and PKC delta, respectively. The ara-C-induced protease activity was sensitive to overexpression of the anti-apoptotic protein Bcl-xL and the baculovirus protein p35. By contrast, overexpression of the cowpox virus protein CrmA blocked apoptosis induced by engagement of the Fas receptor but not that induced by ara-C. CrmA overexpression also had no detectable effect on ara-C-induced cleavage of PKC delta. The results further show that ara-C induces activation of the CPP32 protease by a CrmA- insensitive and p35-sensitive mechanism. Similar results were obtained with cisplatinum, etoposide, and camptothecin. These findings indicate that ara-C and other DNA-damaging agents activate a CrmA-insensitive apoptotic pathway involving CPP32 and that these signals differ from those associated with apoptosis induced by the Fas receptor.     

Stimulation of arachidonic acid metabolism in silica-exposed alveolar macrophages

The molecular events involved in both the initiation and development of silicosis are at present poorly defined, although mediators released from macrophages exposed to silica particles are believed to play a role. We have investigated the in vitro production of arachidonic acid (AA) metabolites in adherent bovine alveolar macrophages (BAM) incubated with crystalline silica. BAM were prelabeled with 3H-AA and incubated with 0.5-5.0 mg silica. Lipid metabolites released into the culture medium were analyzed by high-performance liquid chromatography. Simultaneously, lactate dehydrogenase (LDH) was assayed to provide an indication of cell injury. No 5-lipoxygenase metabolites were detected at the lowest silica dose tested (0.5 mg/well), but 5-hydroxyeicosatetraenoic acid (5-HETE) was the major AA metabolite detected between 1.5 and 5.0 mg of silica. A fivefold increase in the production of leukotriene B4 (LTB4) and its two nonenzymatic diastereomers (Isomers I and II) was observed as the silica concentration was increased from 1.0 to 5.0 mg. In contrast, the release of cyclooxygenase products declined with increasing concentrations of silica. LDH release increased in a linear, dose-dependent fashion in the range of silica doses used. The kinetics of eicosanoid release was investigated over a 3-h interval and LDH release was assayed for each time point. Within 15 min following silica addition, a shift to the production of 5-lipoxygenase metabolites was observed, accompanied by a reduction in cyclooxygenase products. This rapid alteration in AA metabolism preceded cell injury as measured by LDH release. These results demonstrate that silica is a powerful stimulator of arachidonic acid metabolism in BAM. Moreover, silica selectively stimulates the 5-lipoxygenase pathway as the dose of silica increases. Our results suggest that dysfunction in arachidonate metabolism could contribute to the pathogenesis of silicosis.     

Guidelines for international collaborative research

OBJECTIVE: As the global village becomes a reality, there is an increasing need to conduct international collaborative studies in family practice. A workshop at the WONCA meeting in Hong Kong used international attendees to produce a set of guidelines for international research. METHODS: At the workshop four completed international projects, each using a different strategy, were presented so that common themes might become apparent. The themes were then discussed and guidelines emerged from the process. RESULTS: Seven guidelines emerged for consideration before embarking on an international collaborative research project in family medicine. The guidelines deal with the characteristics of the research question and the importance of communication. The need for simple, brief methods of data collection, funding and pilot testing were identified. CONCLUSION: The question must be relevant to all participants to maintain interest and measurement tools must be validated to understand the impact of cultural differences in understanding.      

联苯双酯对鼠肝细胞的生化药理作用

本文结果表明,联苯双酯可增加肝细胞膜流动性。同时,联苯双酯具有保护线粒体结构和功能的作用:消除表面活性剂Triton X-100引起的线粒体肿胀;增加线粒体呼吸控制比;在氧化反应基础上,保持偶联磷酸化,增加线粒体ATP合成效率;促进线粒体对Ca²⁺的摄取。