Genetic ecotoxicology I: DNA integrity and reproduction in mosquitofish exposed in situ to radionuclides

Female mosquitofish (Gambusia affinis) were collected from two sites located on the US Department of Energy's Oak Ridge Reservation that are contaminated with 137Cs, 90Sr, other radionuclides and chemical genotoxicants. Fish from non- radionuclide contaminated environments located off the reservation were also collected. DNA, extracted from liver tissue and blood cells, was examined by gel electrophoresis for structural damage in the form of strand breakage. In general, the level of DNA strand breaks was elevated in fish from radionuclide-contaminated sites with observed differences in the number and type of strand breaks between liver tissue and blood cells. The number of malformed embryos was higher in fish at the contaminated sites, and varied with season. Fecundity was negatively correlated with the level of double strand breaks in the DNA of fish from one contaminated site. Females with broods that included malformed embryos had more DNA strand breakage than those that did not; and furthermore, a threshold effect was observed between the occurrence of malformed embryos and the presence of double strand breaks in the DNA of the mother. These findings have implications for both ecological risk assessment and evolutionary ecology     

Rh phenotype prediction by DNA typing and its application to practice

The complexity of the RHD and RHCE genes, which is the greatest of all blood group systems, confounds analysis at the molecular level. RH DNA typing was introduced in 1993 and has been applied to prenatal testing. PCR-SSP analysis covering multiple polymorphisms was recently introduced for the screening and initial characterization of partial D. Our objective is to summarize the accrued knowledge relevant to the approaches to Rh phenotype prediction by DNA typing, their possible applications beyond research laboratories and their limitations. The procedures, results and problems encountered are highly detailed. It is recommended that DNA typing comprises an analysis of more than one polymorphism. We discuss future directions and propose a piecemeal approach to improve reliability and cost-efficiency of blood group genotyping that may eventually replace the prevalent serology-based techniques even for many routine tasks. Transfusion medicine is in the unique position of being able to utilize the most extensive phenotype databases available to check and develop genotyping strategies.     

食管癌高发及低发区患者DNA修复功能的研究

本文对食管癌高、低发区食管癌患者和正常人,经MNNG诱导的DNA损伤修复功能进行了研究。实验采用外周血淋巴细胞培养的方法。每组又分为对照组及MNNG诱导组。样品以~3H-TdR标记后经液闪仪计数法进行检测。结果发现,低发区正常人经MNNG诱导的DNA损伤修复功能明显高于对照组,两个地区食管癌患者修复能力均低于正常人,与地区无关。     

过氧化氢对白色念珠菌DNA破坏的研究

本文用热变性温度法研究一定浓度 H_2O_2对 C.albicans DNA 破坏作用。结果表明,经6%和10%H_2O_2处理后,C.albicans DNA G c Mol%(分别为28.1±0.82和14.4±1.51)显著低于对照 DNA G C Mol%(85.9±0.62),并推断 H_2O_2可能作用于 C.albicans DNA 碱基以及其间的氢键上;DNA 电泳图谱发现,经3%和6%H_2O_2处理的 C.albicans DNA 电泳带明显不同于对照,提示 H_2O_2更易造成 C.albicans DNA 核苷酸链的降解或断裂.H_2O_2对 C.albicans DNA 的破坏,增强了其杀菌作用。     

宫颈腺癌细胞DNA流式细胞光度分析

应用流式细胞计对３０例宫颈腺癌和混合癌细胞的ＤＮＡ指数和细胞增殖周期各时相细胞分布比例进行分析，结果显示非整倍体肿瘤２９例，占９６．７％．流式细胞计在诊断恶性肿瘤方面是有价值的。细胞增殖周期比ＤＮＡ指数对预后的估价更有意义．乳头型腺癌、分化Ｉ级的肿瘤，Ｓ＋Ｇ２Ｍ比率最低，５年生存率最高．     

聚合酶链反应（PCR）对单纯疱疹病毒性脑炎的临床诊断价值

应用聚合酶链反应（ＰＣＲ）检测技术对１１８例颅内感染性疾病患者及３７例无神神经系统疾病患者脑脊液（ＣＳＦ）中的单纯疱疹病毒ＤＮＡ（ＨＳＶ－ＤＮＡ）进行了检测及分型。结果提示：“散发性脑炎”组的阳性率为３８．４６％（２０／５２），细菌、真菌性脑膜炎、其它病毒性脑炎组以及无神经系统疾病组均为阴性。作者认为：①本检测是目前单纯疹病毒性脑炎（ＨＳＥ）较为简便而准确的早期诊断方法之一；②ＨＳＶ分型检测，对病原诊断更具有全面性；③两型单纯疱疹病毒均可引起ＨＳＥ。     

原发性肝癌DNA含量与核形态学参数关系的分析及其临床意义

本研究图像分析技术（ＩＡＴ）对５５例原发性肝癌（ＰＨＣ）病人的ＤＮＡ含量及核形态学参数进行检测，结果显示：无１例ＰＨＣ的ＤＮＡ干系水平睡于ＤＮＡ含量二倍体区域，３例处于近二倍体（５．４５％），５２例处于异倍体（９４．５５％）。ＤＮＡ含量与有无淋巴结转移（Ｐ〈０．０５）、瘤体大小（Ｐ〈０．０１）、生存率（Ｐ〈０．００１）有相关性。核形态学参数与ＰＨＣ的ＤＮＡ含量及ＰＨＣ有无淋巴结转移亦有统计学意义。     

赖型钩端螺旋体重组DNApCX7的特异性鉴定和限制性内切酶谱分析

本实验将赖型钩端螺旋体（简称钩体）ＤＮＡ基因库的克隆ｐＣＸ７制备成￣（３２）Ｐ－重组ＤＮＡ探针，对８个不同血清群的１７株问号状钩体、双曲钩体ＰａｔｏｃⅠ株以及细螺旋体３０５５株ＤＮＡ进行打点杂交；同时用１５种ＤＮＡ片断进行限制性内切酶谱分析。结果表明，该重组ＤＮＡ具有问号状钩体种（Ｓｐｅｃｉｅｓ）特异性，但与不同问号状钩体之间的同源性程度有差别；限制性内切酶谱分析发现ｐＣＸ７重组ＤＮＡ片段长约１．７ｋｂ，具有１个Ｂｇ１Ⅱ识别位点和３个ＢｓｔＢ１识别位点。     

结节性甲状腺肿及其非典型结节与甲状腺癌细胞核DNA定量研究

作者对结节性甲状腺肿及其非典型结节与甲状腺癌细胞核直径、面积及 DNA 含量检测,发现核直径与面积的(?)和 S 为甲状腺癌组>非典型结节组>对照组(P<0.01);随着细胞增生异型程度的加重,核直径、面积及离散程度随之增加、DNA 含量也显著增加,显示Ⅲ级 DNA 含量细胞出现频率越高恶性的可能性就越大;同时发现各组细胞核不同 DNA 含量的核直径、面积均明显增加,与对照组相比差异生非常显著(P<0.01)。