Concentration level and distribution of polycyclic aromatic hydrocarbons in soil and grass around Mt. Qomolangma, China

High mountains may serve as a condenser for persistent organic pollutants. In the present study, soil and grass samples from Mt. Qomolangma region, China were collected from 4600 to 5620 m a.s.I and were analyzed for polycyclic aromatic hydrocarbons （PAHs） to determine if they are concentrated at colder, more elevated sites and to evaluate their possible resources and fractionation. The total PAHs concentration in soil samples was 〈 600 ng g^-1, the critical value to differentiate PAHs levels in remote and urban regions. This implied the PAHs levels at Mt. Qomolangma are relatively low and what one might expect in such a remote region of the world. These low values may represent a soil background for mid-latitude Northern Hemisphere soils away from the direct influence of an anthropogenic source. As for the distribution pattern, the low molecular weight PAHs were prone to accumulate at higher altitude, while the high molecular weight PAHs inversely related or unrelated with elevation. Based on high concentration of phenanthrene at elevated sample site and the ratios of individual PAHs, we deduced that home-heating combustion and vehicle emission may result in the constitution trait of PAHs in this mountain region. Monsoon traveling over India, Pakistan and other countries with dense population may carry contaminant to Mt. Qomolangma region.     

Melkersson-Rosenthal综合征3例临床分析

Melkersson-Rosenthal综合征，是一种罕见的神经，皮肤粘膜综合征，临床以间歇性面瘫，再发性唇面肿胀及皱襞舌为三主症，激素治疗有显著疗效，但国内报道极少，早期诊断困难，易被诊，本文报道我院近十年来收治的3例完全型MRS病人及随访资料，结合国内外文献，就其病因，发病机制，临床特征及近年来研究进展进行分析，认为该病发病机理可能与免疫功能异常所致组织炎性肉芽肿有关。     

鼻咽癌放疗致放射性口腔粘膜炎的预防及护理对策

本文介绍了放射性口腔粘膜炎的预防及护理方法。实施正确、有效的护理措施，不仅减轻了患者的痛苦，提高了生活质量，也是鼻咽癌患者放疗顺利完成的重要保证。     

钛合金组合式螺旋柱状人工牙根种植体及种植术的临床研究应用及修复

本文地１９９５年７月－１９９６年６月引进卫生部口腔种植科技中心－华西医科大学口腔医学院研制的钛合金二段式组织螺旋柱状，人工牙根种植体及骨内研究临床１００例，男８８例，女１２例，成功率达９８％，取得了满意的效果。     

碘樟合剂治疗牛乳房炎临床效果观察

<正>我团于2003年从澳大利亚引进荷斯坦母牛950头,经过两年多的饲养,在普通病的发生方面,据统计,乳房炎的发生可占其总发病率85%。由于该病是由多种病原微生物引     

超细HA涂层Ti基底复合种植体的制备新工艺

探讨了用溶胶－凝胶法（简称ＳＯＬ－ＧＥＬ）多次重复涂层烧结ＨＡ－Ｔｉ复合种植体，使多层超细ＨＡ涂层粉末的纯度、结晶度和ＨＡ晶体的纳米结构得到改善的工艺条件，此工艺能使涂层与基底材料各组分相互混合达到分子水平的均匀，并在界面生成牢固的化学过渡层。     

停乳链球菌ISP基因的克隆与表达及其免疫原性研究

根据GenBank报道的停乳链球菌免疫分泌蛋白基因(immunogenic secreted protein,ISP)序列设计引物,PCR扩增得到1 550bp的isp片段,其基因序列与GenBank提交序列的同源性为98.13%.将isp基因与表达载体pET-25b(+)连接,成功构建重组质粒pET-25b(+)-isp.转化大肠杆菌BL21(DE3),成功得到阳性表达重组菌株BL21(pET-25b(+)-isp).经IPTG诱导后,SDS-PAGE与Western blot检测得到约55ku的目的蛋白.经优化确定,isp蛋白的最优表达条件:1mmol/L IPTG,37℃诱导18h,且此时表达的蛋白具有良好的抗原性.该研究制备了奶牛乳房炎停乳链球菌的基因工程疫苗,并对其免疫原性进行了探究,为奶牛乳房炎的免疫防治奠定了基础.