Multivariate comparison of elemental concentrations in human teeth

R-mode factor analysis was applied to characterize the chemical composition of human teeth investigated by particle induced X-ray emission (PIXE), Rutherford backscattering spectrometry (RBS) and X-ray fluorescence (XRF) techniques. The approach developed in this study enabled the separation between essential mineral teeth components and the pollutants deposited in teeth tissues during the human life. The three independent sources of metals incorporated in human teeth were found. The first source, representing about 43% of the variance of the concentration data, was characterized by pollutant elements of power industry emissions. The second factor was loaded with toxic elements of general urban pollution. The third factor represented the tooth source as it contained mainly large fractions of the mineral components of the tooth tissue as Ca and K.     

Design and conduct of occupational epidemiology studies: III. Design aspects of case-control studies

Currently available approaches for the design of occupational case-control studies are reviewed. An accompanying paper reviews methods of analysis. We commence by drawing a distinction between cohort-based and registry-based studies. Methods for selecting cases and controls are then reviewed, including cumulative incidence and incidence density sampling, matching, sources of controls, and issues in control selection. Finally, the advantages and disadvantages of the case-control approach are summarized.     

静脉性脑梗死动物模型的建立及相关研究

静脉性脑梗死动物模型的建立是通过不同的栓塞方法闭塞实验动物上矢状窦的不同部位，其目的是观察脑组织的血流量、血氧饱和度、脑组织水含量、脑灌注压、及各种影像学表现等参数指标的变化，从病理生理角度探讨静脉性脑梗死的发病机理及演变过程。     

手术治疗Pilon骨折34例

Pilon骨折是涉及胫骨踝关节面损伤的胫骨远端干骺端骨折,近年来随着高能量损伤的增多,该类型骨折有增加的趋势,自2000-2005年,采用切开复位内固定的方法治疗Pilon骨折34例,疗效满意,现总结报告如下。1临床资料本组34例,男28例,女6例;年龄13~73岁,平均为40.6岁。车祸伤16例,高处坠落伤18例。开放骨折4例。合并颅脑损伤2例,胸腰椎骨折5例,跟骨骨折1例,腓骨下1/3骨折19例、中段骨折7例。其中按R櫣edi-Allg wer分型[1]:Ⅱ型骨折13例,Ⅲ型骨折21例。伤后就诊时间1h~5d,伤后至手术时间2h~14d,平均9.5d。2治疗方法2.1闭合损伤软组织肿胀严重者,先…     

连续埋线法重睑术的临床评价

目的 探讨连续埋线法重睑术的适应证和手术要点.方法 手术在局部麻醉下施行,从外眦向内眦沿睑板上缘作连续缝合,然后折返,外眦缝合口打结.结果 本组132例患者术后随访形成良好重睑者为121例,占92%;两侧重睑皱襞高低不一的7例,占5%;重睑消失的4例,占3%,后两者均补充埋线法或者切开法重睑术修复.结论 连续埋线法重睑术除适用于上睑皮肤较薄的年轻患者,也可扩大到中等以下程度的上睑皮肤松弛患者,以及以外侧为主的上睑臃肿者.     

Undergraduate psychiatry teaching in Ethiopia

Many epidemiological studies have shown the magnitude and seriousness of mental disorders in developing countries. However, mental health care remains unsatisfactory owing to lack of skilled manpower and many other social and medical priorities. General practitioners and other health personnel can significantly help in extending mental health care provided they receive adequate training during their medical curriculum. With this aim, the Department of Psychiatry at Addis Ababa University runs a 6-week full-time course for undergraduate medical students. Its chief objectives, teaching methods, achievements and shortcomings are discussed in the paper.     

用放免法测定脐血清中T_4T_3及TSH浓度筛选先天性新生儿甲低

本文用放免法测定脐血清T_4值(727例),T_3值(556例)及TSH值(700例)筛选先天性新生儿甲低。T_4值量男为9.56±4.29ug/dl,女为10.15±4.35ug/dl;T_3值量男为86.06±63.42ngldl,女为85.61±44.42ngld;TSH值男为13.77±12.69mIu/ml,女为13.94±12.51mIu/ml。三种激素男女之间均无显著差别,对24例可疑甲低复查了静脉血清T_4、T_3、TSH含量,T_4值均较脐血清高;T_3值较脐血清高出2—3倍TSH值均降到成年人水平。否定了甲低。并对早期诊断的取样问题进行了讨论。     

老年人急性阑尾炎的腹腔镜手术治疗

目的 探讨老年人急性阑尾炎的临床特点，更好地把握腹腔镜阑尾切除（LA）术的方法和特点。方法 回顾分析50例老年人急性阑尾炎LA的临床资料。结果 LA均获成功，患者全部治愈，无严重的并发症发生，肠功能恢复时间及住院时间均缩短。结论 老年人反应迟钝，阑尾炎进展快，易发生坏疽及穿孔，合并症多，手术风险较高，LA是安全、可行的，除个别腹膜后阑尾炎外，其余均可施行LA。     

A simulation study of three sequential methods for the comparison of two treatment groups when the response criterion is censored

Three recent sequential methods, group sequential analysis (GSA), the sequential probability ratio test (SPRT) and the triangular test (TT) are well suited to randomized clinical trials with a censored response criterion, as they do not require matched pairs of patients. We undertook a simulation study to investigate their statistical properties and to compare these three methods with the fixed-sample design. Our results suggest that the three methods have the expected statistical properties for size and power; they allow an important reduction of the average number of events before stopping, except with GSA when there is no treatment difference; the triangular test (closed design) appears the optimal design, as the variance of the number of events is smaller than with the sequential probability ratio test (open design) and analysis after every twenty new events does not alter the statistical properties of these sequential methods and enhances their usefulness.