巢湖水有机提取物致鱼红细胞DNA损伤的初步观察

目的　研究巢湖水有机提取物致突变性。方法　单细胞凝胶电泳技术测定鱼红细胞DNA损伤效应。结果　巢湖源水引起慧星细胞的百分率最高 (5 7.2 5 % ) ,滤前水最低 (2 7.6 3% ) ,出厂水经过二次加氯后慧星细胞的百分率有所上升 (4 4 .0 0 % )。结论　巢湖源水具有潜在致突变性 ,经混凝、活性炭吸附及沉淀处理后其DNA损伤作用有所下降 ,但氯化消毒可增加水中有机提取物的DNA损伤作用。     

Cerivastatin inhibits fetal calf serunvinduced DNA synthesis in cultured rat mesangial cells

SUMMARY: Inhibition of mevalonate synthesis by several statins has been shown to suppress DNA synthesis in glomerular mesangial cells. In the present study, we investigated the effect of a new statin, cerivastatin, on fetal calf serum (FCS)-induced DNA synthesis of cultured rat mesangial cells. Cultured rat mesangial cells were stimulated by 10% FCS in the presence or absence of cerivastatin and mevalonate. 5-bromo-2-deoxyuridine (BrdU) incorporation was used to assess DNA synthesis. the present study showed that 10% FCS caused marked stimulation of DNA synthesis in the mesangial cells. Cerivastatin inhibited FCS-stimulated BrdU incorporation in a dose-dependent manner. IC₅₀ was approximately 1 umol/L. Exogenous mevalonate, farnesyl pyrophosphate and geranylgeranyl pyrophosphate significantly prevented the inhibitory effect of cerivastatin on DNA replication. It appears that cerivastatin, by inhibiting the synthesis of mevalonate, may suppress DNA synthesis in the mesangial cells.     

Andrology: Application of different in-situ hybridization detection methods for human sperm analysis

The detection of some types of aneuploidy in human spermatozoacan be based on the use of the fluorescence in-situ hybridizationtechnique (FISH). One of the crucial steps for FISH is to achievea proper decondensation and denaturation of the DNA in the specimen,so as to obtain efficient hybridization results. However, afterDNA decondensation the morphology of sperm heads is partly distortedand the majority of the tails is lost. This situation leadsto problems in the distinction between disomic and diploid spermatozoa,as well as between abnormal spermatozoa and somatic cells. Double-and triple-target FISH can partly solve this discriminationproblem. To improve these procedures we adapted the steps ofdecondensation and visualization of the single sperm cells.Firstly, DNA decondensation with 25 mM dithiothreitol in 1 MTris at pH 9.5 resulted in sperm cells with intact morphologyof both the head and the tail, and allowed efficient single-,double- and triple-target ISH to be performed. Secondly, weapplied a novel detection method, based on enzyme immunocyto-chemicalreactions, with coloured precipitation products. Thirdly, thisISH procedure was combined with Diff-Quik staining and bright-fieldmicroscopy. This absorption method has the advantage of a permanentsignal, and the adapted cytoplasmic staining of the sperm plasmamembrane allows the visualization of the outline of the singlespermatozoon. Using this approach, therefore, it is possibleto discriminate between disomic, diploid and abnormal spermatozoa,somatic cells and spermatozoa that overlap, because the morphologyof the cells is not distorted and the tails of the spermatozoaare intact and properly visualized.     

荧光定量PCR和ELISA检测乙肝病毒的应用比较

目的　探讨荧光定量PCR检测HBV—DNA的应用价值。　方法　从 2 92 0份用ELISA检测乙肝 5项的体检血清标本中 ,抽取 2 88份HBsAg阳性标本及 10 0份全阴标本 ,进行荧光定量聚合酶链式反应 (FQ—PCR)HBV—DNA定量分析。　结果　经FQ—PCR检测 ,80份HBsAg、HBeAg、HBcAb都阳性的标本 ,HBV—DNA阳性率为 10 0 % ( 80 /80 ) ,平均HBV—DNA拷贝数为 2 2× 10 8cp/ml ;164份HBsAg、HbeAb、HBcAb都阳性的标本 ,HBV—DNA阳性率为79 3 % ( 13 0 /164 ) ,平均HBV—DNA拷贝数为 1 5× 10 6cp/ml;12份HBsAg单项阳性的标本 ,HBV—DNA的阳性率为83 3 % ( 10 /12 ) ,平均HBV—DNA拷贝数为 1 6× 10 5cp/ml;10 0份HBsAg、HBsAb、HBeAg、HBeAb、HBcAb都阴性的标本 ,HBV—DNA的阳性率为 2 % ( 2 /10 0 ) ,平均HBV—DNA拷贝数为 4 5× 10 5cp/ml。　结论　FQ—PCR可以检测HBV的感染和复制情况 ,对准确报告HBV感染 ,指导其选择治疗方案和观察疗效具有重要的临床意义     

转基因食品的快速PCR鉴定

用十六烷基-二甲基-乙基-溴化铵(CTAB)法快速高效地从样品中提取了可供分析的基因组DNA,经PCR扩增,鉴定了含有35S启动子和NOS终止子的转基因样品.该方法的灵敏度可达0.1%,并且具有很好的稳定性.     

荧光偏振检测HBV DNA C区BCP双突变

目的：建立简便、灵敏的HBV DNA序列中BCP双突变点的检测方法．方法：采用终点终止法和偏振光检测技术进行点突变的检测．首先对HBV C区基因进行PCR扩增，然后用特异探针与扩增产物中待测核苷酸的下游序列杂交，使探针的3’端可以在DNA聚合酶的催化下，依据其互补链上的待测核苷酸连接上一个标有特定荧光素的ddNTP，然后检测该3’端带有荧光素的探针，根据检测到的荧光素种类和偏振光的强度可以判定待测点是何种核苷酸．结果：该方法可以检测出HBV基因序列中BCP双突变核苷酸类型以及检测1个拷贝的模板，并且可以从BCP野性株DNA序列中检出5％BCP双突变DNA序列．结论：该技术可以检测血清中HBV DNA C区BCP双突变．     

Perinatal lung development following maternal exposure to methylmercuric chloride

Mercury ingested from dietary sources has potent neurotoxic and teratogenic effects. Initial studies have shown that mercury may also affect fetal lung development. Since these pulmonary effects may play a role in subsequent neonatal morbidity and mortality due to compromising of the development of the lung, mercury effects in fetal and neonatal lung were investigated. Methylmercuric chloride (MMC), 1,000 ppm (15 mg/kg of body weight), was administered via an intragastric tube to timed-pregnant Swiss/Webster mice on day 9 of gestation. Lungs from fetuses on gestational day 18 and from neonates on days 1, 5, or 10 after birth were studied. Significant changes in MMC-exposed lungs compared to controls occurred at postnatal day 1. At this time, lung weight per gram body weight increased, phospholipid content per gram of lung or per microgram of DNA decreased, while DNA per gram of lung increased. Methylmercury appears to have delayed lung maturation. Cuboidal epithelial cells in alveolar tubules contained conspicuous glycogen deposits, and differentiation of alveolar type II cells was adversely affected. These results suggest that prenatal exposure to methylmercury may be detrimental to lung development, specifically to the initiation of surfactant synthesis, by delaying the normal pattern of maturation of the alveolar type II cells within the lungs. Pediatr Pulmonol. 1994; 17:11–21 . © 1994 Wiley-Liss. Inc.     

Applications of DNA Flow Cytometry and Fluorescence In situ Hybridization Using a Chromosome-specific DNA Probe on Paraffin-embedded Tissue Sections of Primary Malignant Melanomas

We have applied DNA flow cytometric analysis to paraffin-embedded tissue sections of primary malignant melanomas. Conventionally, flow cytometric analysis of paraffin-embedded tissue sections has been done by the method of Hedley et al. We added ultrasound treatment to the method of Hedley et al. and a lower value of coefficient of variation was shown. Furthermore, a new technique, fluorescence in situ hybridization with a chromosome-specific repetitive DNA probe, was used for the analysis of chromosomal numerical aberrations in the same paraffin-embedded tissue sections. The DNA flow cytometric analysis showed that in 8 cases six primary malignant melanomas were of the aneuploid pattern and two cases of lentigo maligna (melamona in situ) were of the diploid pattern. By fluorescence in situ hybridization, the two cases with the diploid pattern had spots/nucleus of 1.28 and 1.12, and those with the aneuploid pattern had spots/nucleus from 2.01 to 2.27. Only one nodular melanoma in an aneuploid case showed spots/nucleus of 1.71. These data indicate that fluorescence in situ hybridization with chromosome-specific repetitive DNA probes can serve as a cytogenetic tool for the analysis of interphase nuclei of solid human tumors and may be useful for the study of tumor cell heterogeneity.     

用DNAG C含量和DNA同源性测定法鉴定米克戴德军团菌

本文采用热变性温度法和液相复性速率法对—轻型特征及血清学反应相似米克戴德军团菌(Lm)的菌株进行了测定,结果表明该菌与标准Lm(C DC株)的DNA G Cmol％相差3.45％,与标准Lm(C DC株)的DNA同源性达81.99％,根据伯杰细菌鉴定手册(1984),可判定该菌株与标准Lm(C DC株)为遗传型一致的类群,即从遗传学角度证明该菌为Lm。     

DNA限制性内切酶分析应用于伴放线放线杆菌的鉴定和分型

本文用限制性内切酶分析(REA)作伴放线放线杆菌(Aa)的鉴定和分型研究,提取Aa染色体DNA,井分别用BamHI、HindⅢ,Sal Ⅰ和Xho Ⅰ消化,作琼脂糖凝胶电泳。结果显示,Aa和嗜沫嗜血杆菌的DNA片段图谱明显不同;分属于两种不同血清型的两株Aa菌株,其DNA片段图谱也明显不同。这表明,REA可用于Aa菌的鉴定和分型,在所用的4种酶中,以Sal Ⅰ和Xho Ⅰ消化的DNA片段图谱差异最明显。