The role of Self-Defined Race/Ethnicity in Population Structure Control

Population-based association studies are powerful tools for the genetic mapping of complex diseases. However, this method is sensitive to potential confounding by population structure. While statistical methods that use genetic markers to detect and control for population structure have been the focus of current literature, the utility of self-defined race/ethnicity in controlling for population structure has been controversial. In this study of 1334 individuals, who self-identified as either African American, European American or Hispanic, we demonstrated that when the true underlying genetic structure and the self-defined racial/ethnic groups were roughly in agreement with each other, the self-defined race/ethnicity information was useful in the control of population structure.     

Effect of divalent cations on structure-function relationships of the antitumor protein α-sarcin

α-Sarcin binds one Zn(II) cation per protein molecule, with a K_d value of 0.9 mM, determined by equilibrium dialysis experiments. Ca(II), Mg(II), and Mn(II) do not bind to α-sarcin. Cd(II) and Co(II) also behave as Zn(II). The binding produces local modifications on the protein conformation affecting the microenvironment of tryptophan residues. The three cations modify the fluorescence emission of the protein. The near-u. v. circular dichroism spectrum of the protein is also altered. The binding of Zn(II) and related cations does not modify the secondary structure of the protein. The ribonucleolytic activity of a-sarcin is inhibited upon Zn(II) binding, but no alteration of the ability of the protein to aggregate phospholipid vesicles has been observed.     

Sperm chromatin integrity in young men with no experiences of infertility and men from idiopathic infertility couples

Damage to the genetic component of spermatozoa seems to play the main role in a majority of cases where current approaches fail to reveal the specific cause of male infertility. In this study, we compared semen quality in men assigned to two defined groups: men from couples with unexplained infertility – idiopathic infertility (A) and young men with no experiences of infertility (B). All samples were examined by standard ejaculate analysis and sperm chromatin structure assay (SCSA). Sperm chromatin damage was significantly higher in men from group A than in those from group B. Similar results were obtained by comparison of men from group A (all men were normozoospermic) with normozoospermic men from group B. According to these results, we can suppose that chromatin disorders may be the causal factor of subfertility or infertility in some of these men. No evidence for a strong association between chromatin disorders and standard parameters of ejaculates was found. We failed to confirm a relationship between smoking and sperm quality in men from any of the investigated groups. SCSA is a method that facilitates the identification of infertile men who otherwise show normal semen variables.     

压膜式间隙保持器的临床应用

目的:观察正压压膜式间隙保持器的临床应用特点和效果.方法:选择60例5.9～10岁的乳牙过早缺失的患儿,随机分为实验组和对照组,实验组用正压压膜式间隙保持器,对照组用带环式丝圈间隙保持器.分别从患者对保持器的接受程度、保持器的制作、椅旁操作时间、固位效果及其保持疗效和因保持器本身问题导致的复诊率进行对比研究,并对测量数据进行统计学处理.结果:两组患者在对保持器的接受程度、保持器的制作、椅旁操作时间、美观、防止对合牙过度伸长方面具有显著的差异,在固位效果及其保持疗效和因保持器本身问题的复诊率上有差异,但是差异没有显著性.结论:正压压膜式间隙保持器是一种美观舒适,制作简单,戴用便捷、固位好,疗效佳,便于观察恒牙萌出程度的间隙保持器,它为口腔医师进行保持缺隙治疗时提供了一种新的选择.     

36例原发胃肠道淋巴瘤的诊断和治疗

目的：探讨提高原发胃肠道淋巴瘤术前诊断率及治疗效果的方法。方法：对36例原发胃肠道淋巴瘤患者的临床表现、体征及辅助检查进行分析，通过COX回归等统计方法对其预后因素及生存率等进行分析。结果：该病临床表现无特异性；诊断主要依靠内窥镜病理活检；手术方式、综合治疗完成情况、临床分期为与预后有关的影响因素。结论：提高对该病临床表现及内镜、造影检查特点的认识，采用正确的活检方法是提高术前诊断率的关键；以手术及化疗为主的综合治疗措施是提高疗效的关键。     

Working‐correlation‐structure identification in generalized estimating equations

Selecting an appropriate working correlation structure is pertinent to clustered data analysis using generalized estimating equations (GEE) because an inappropriate choice will lead to inefficient parameter estimation. We investigate the well‐known criterion of QIC for selecting a working correlation structure, and have found that performance of the QIC is deteriorated by a term that is theoretically independent of the correlation structures but has to be estimated with an error. This leads us to propose a correlation information criterion (CIC) that substantially improves the QIC performance. Extensive simulation studies indicate that the CIC has remarkable improvement in selecting the correct correlation structures. We also illustrate our findings using a data set from the Madras Longitudinal Schizophrenia Study. Copyright © 2008 John Wiley & Sons, Ltd.     

原发性肝癌患者外周血IL-2,sIL-2R,TNFa水平及NK细胞活性检测

目的 :检测原发性肝癌患者外周血IL -2,sIL -2R,TNFa水平及NK细胞活性 ,并探讨患者细胞免疫功能低下的原因。方法 :采用MTT法检测30例原发性肝癌患者外周血单个核细胞白细胞介素2(IL -2)的诱生水平 ;采用ELISA法检测血清可溶性白细胞介素2受体 (sIL -2R) ,肿瘤坏死因子a(TNFa)水平 ;自然杀伤细胞活性 (NK -A)检测采用MTT法。结果 :原发性肝癌患者外周血TNFa水平降低 (P<0.01) ;IL -2、NK -A活性水平低于对照组 (P<0.05) ;sIL -2R水平高于对照组 (P<0.01)。结论 :原发性肝癌患者Th1细胞因子及NK -A活性有所降低 ,检测该指标有助于了解患者机体细胞免疫功能及预后评估。     

酸碱对药所含酸碱性成分共煎形成复合物的结构研究

目的:研究乌头碱与甘草酸、乌头碱与大黄酸、小檗碱与大黄酸、麻黄碱与甘草酸在煎煮条件下形成的大分子复合物的结构.方法:采用X-射线光谱仪测定反应物及反应产物的结合能,用量子化学密度泛函理论计算各反应产物的基态电荷分布情况.结果:4对化合物中乌头碱与甘草酸、乌头碱与大黄酸、小檗碱与大黄酸的结合能在反应前后发生了改变,酸性成分的分子结构中特征性原子有较高正电荷,碱性成分的分子结构中特征性原子有较高负电荷.结论:4对化合物中乌头碱与甘草酸、乌头碱与大黄酸、小檗碱与大黄酸结合形成复合物.麻黄碱与甘草酸未形成复合物.     

一种识别蛋白质的保守氨基酸残基的新方法

保守氨基酸残基在生物进化过程中具有较强的稳定性,一般不会发生太大的变化;生物信息学认为：氨基酸序列决定蛋白质结构,蛋白质结构决定蛋白质功能。因此,作者基于氨基酸的生化特性、几何特性和动态特性描述了一个新颖的算法去发现蛋白酶家族中的保守氨基酸残基,而保守氨基酸残基将对蛋白质的结构和功能的研究具有重要的意义。     

支气管肺癌伴其它部位多原发癌的影像诊断(附25例报告)

经病理确诊的527例原发性支气管肺癌(PBC)(1972～1987)中,PBC伴其它部位多原发癌(MPC)25例(4.7％)。其中双原发肺癌(DPBC)、12例(2.3％),PBC伴消化道癌6例(1.14％)。25例中共有原发癌灶52个,其中2例为3原发癌;同期组6例(其中DPBC 4例),后期组19例(其中14例间隔3年以上,内2例分别间隔14年及25年)。组织类型相同者8例,不同者4例。 25例MPC特点如下:1.55岁以上20例(80％);2.24例(96％)第2原发癌为1980年后发现;3.第2原发癌为肺癌者23例(92％);4.双原发肺癌12例(48％)。上述特点说明80年代老年人中MPC,尤其是肺癌发病率增高。 本文着重对第2原发肺癌的影像学表现和鉴别诊断进行讨论。