Prenatal diagnosis of chinese homozygous α-thalassaemia 1 and haemoglobin H disease by analysis of α- and φζ-globin genes in chorionic villi and amniocytes

Eighty-eight high-risk pregnancies, 81 for homozygous α-thalassaemia 1 and 7 for haemoglobin (Hb) H disease, were collected in this study. Chorionic villus sampling (CVS) was done in 63 cases and amniocentesis in 25 cases to obtain fetal cells. Southern blotting and DNA hybridization with α- and φζ-globin gene probes were used to determine the α-globin gene status. In two non-informative families with non-deletional mutations, DNA analysis failed to rule out the affected condition, and fetal blood sampling (FBS) and Hb electrophoresis were used for the final diagnosis. In the 81 fetuses at risk for homozygous α-thalassaemia 1, 17 (13 by CVS and 4 by amniocentesis) were afffected, 30 were α-thalassaemia 1 heterozygotes, 19 were normal, and the remaining 15 were either normal or heterozygous. In the seven fetuses at risk for Hb H disease, one was normal, three were α-thalassaemia 1 heterozygotes, two were α-thalassaemia 2 heterozygotes, and one was affected with Hb H disease and developed hydrops fetalis. DNA analysis on fetal cells enabled us to diagnose prenatally severe α-thalassaemias, to prevent the birth of infants with Hb H disease, and to minimize maternal obstetrical complications from harbouring a fetus with Hb Bart's hydrops fetalis.     

柴油车尾气的致突变作用

用大鼠肝细胞悬液程序外ＤＮＡ合成试验（ＵＤＳ），来检测５种柴油机颗粒物的致突变活性，结果显示国产及进口的轻、中、重型柴油机，其排出颗粒提取物均能引起大鼠肝细胞ＵＤＳ试验的ＣＰＭ值升高，且有一定的剂量－反应关系，说明柴油机排出的颗粒提取物存在细胞遗传毒性；各牌号比较发现其颗粒物致突变性的轻型车大于中、重型车，国产车大于同类进口车的趋势。     

环境物质稀土多元复合肥对玉米根尖细胞DNA的损伤

有关对稀土多元复合肥(RE-MECF)的卫生毒理研究较多,但对其遗传毒理研究报道较少.在此,采用了单细胞凝胶电泳技术,探知RE-MECF对玉米细胞DNA是否会产生损伤,以期引起注意.用不同梯度浓度的RE-MECF对农作物玉米进行染毒6 h后,将玉米根尖细胞制备成原生质体,再进行单细胞凝胶电泳,确定对DNA损伤并探讨其剂量-效应关系.结果显示,质量浓度为10 mg·L-1剂量组与阴性组比较没有显著性差异;质量浓度在102～103 mg·L-1剂量范围内彗星细胞的头长随着剂量的增加而缩短,而尾长随着剂量的递增而增长.与阴性组比较存在显著性差异,DNA拖尾率、损伤率随着剂量的增加相应升高;质量浓度在104mg·L-1剂量组彗星的头长和尾长与阴性组相比皆无显著性差异.实验结果表明:RE-MECF对玉米根尖细胞DNA具有一定的损伤作用.     

兰州地区空气飘尘对人淋巴细胞SCE的诱发及DNA的损伤

用苯、己烷、异丙醇(7:2:1)混合溶剂萃取兰州市石油化工区及离市区西64公里农村的空气飘尘.萃取物能使人淋巴细胞姊妹染色单体互换频率(SCE)增高,使SCE比对照组增高一倍的浓度:化工区为23μg/ml、农村为47μg/ml,萃取物还能损伤DNA棋板,证明化工区空气飘尘的致突变或致癌的机率比农村大.     

DNA加合物8-氢基脱氧鸟苷特性研究

作为DNA氧化损伤的生物学标志物，8-羟基脱氧鸟苷（8-OH-dG）的特性研究，对稳定、灵敏、准确地定量8-OH-dG，进而研究有毒化学物质对生物体内的氧化损伤很重要，该文研究了氧化损伤DNA中8-OH-dG的分析、水解、储存、稳定性等方面的问题，采用Fenton型产羟自由基系统如螯合剂Fe^2 -H2O2为氧化源，与脱氧鸟苷和小牛胸腺DNA反应，生成的8-OH-dG用高压液相色谱-电化学法检测，并对8-OH-dG的分析条件进行优化，该法最低检出限为32fmol，比光学吸收法高2～3个数量级，线性范围可高达4个数量级，从0.32pmol到3.2nmol，相关系数0.9996。并对酶水解DNA的条件、储存酸度、中性偏酸的缓冲液中损失较少，其形成与所处介质环境有关，在氧化源存在或有氧环境中一定时间内有积累作用，添加抗氧化剂等干预措施后，能灵敏而稳定地对DNA中的8-OH-dG进行测定。     

Prenatal diagnosis of X-linked retinitis pigmentosa (RP) in five pregnancies at risk

Five pregnancies at risk for X-linked retinitis pigmentosa (RP) have been monitored by first-trimester prenatal diagnosis using DNA markers flanking the RP2 and RP3 loci. Three affected and two unaffected fetuses, including a female carrying a wild-type genotype, were predicted on the basis of marker segregation and estimation of the recombination fraction.     

Recycling greenhouse gas fossil fuel emissions into low radiocarbon food products to reduce human genetic damage

Radiocarbon from nuclear fallout is a known health risk. However, corresponding risks from natural background radiocarbon incorporated directly into human genetic material have not been fully appreciated. Here we show that the average person will experience between 3.4 × 10¹⁰ and 3.4 × 10¹¹ lifetime chromosomal damage events from natural background radiocarbon incorporated into DNA and histones, potentially leading to cancer, birth defects, or accelerated aging. This human genetic damage can be significantly reduced using low radiocarbon foods produced by growing plants in CO₂ recycled from ordinary industrial greenhouse gas fossil fuel emissions, providing additional incentive for the carbon sequestration.     

狼蛛优势种群的12S rRNA对长期农药胁迫的分子响应

应用12SrRNA基因序列分析探讨了狼蛛优势种群对长期农药胁迫的分子响应机制.研究显示:(1)拟水狼蛛Piratasubpiraticus和拟环纹豹蛛Pardosapseudoannulata在长期农药胁迫下的12SrRNA基因第三结构域序列均发生了明显改变,即碱基组成由315bp和300bp分别减少为301bp和299bp,转换/颠换为17/5和11/10,核苷酸变异百分数达到0.095和0.083,同源性仅分别为85.8%和91.7%;(2)分子水平上表明拟水狼蛛较拟环纹豹蛛对农药的胁迫更为敏感;(3)供试两种狼蛛标本的基因组DNA的4个碱基对中以A和T的变异频率最高,属农药敏感型碱基对;(4)长期农药胁迫下供试两种狼蛛标本的12SrRNA基因片段的共同突变位点规律显示:192～228片段是其农药胁迫的敏感区.图2表3参9     

二氧化硫亚慢性染毒对大鼠肺细胞DNA的损伤

为了探讨低浓度SO2长期暴露对哺乳动物肺细胞DNA的影响,采用动式吸入法(SO2浓度为28mg/m3)对Wistar大鼠染毒30d,运用单细胞凝胶电泳技术(彗星试验)研究了SO2亚慢性染毒对大鼠肺细胞DNA的损伤作用.结果表明,SO2可引起雌、雄性大鼠肺细胞核DNA迁移长度显著增加(P<0.01),且SO2对雄性小鼠肺细胞DNA损伤比雌性小鼠严重;经染毒后,与对照组相比,大鼠的体重减轻,肺体比增加.这些结果表明,较低浓度的SO2也具有引起哺乳动物肺细胞DNA突变的潜在危险.表3参15