Duchenne型肌营养不良症

作者综述了１０年来对Ｄｕｃｈｅｎｎｅ型肌营养不良症（ＤＭＤ）的研究概况。主要包括①ＤＭＤ的临床研究。②血清生化研究表明ＣＫ、ＬＤＨ、Ｍｂ是诊断ＤＭＤ病人和携带者的敏感指标。③心脏无创性检测和肌肉超微结构研究。④部分抗肌萎缩蛋白基因ＹＡＣ物理图谱，精细限制酶图谱和缺失热区的核苷酸顺序分析，首次发现内含子中ＡＴ富集区的同源顺序与ＤＭＤ断裂有关。⑤抗肌萎缩蛋白的缺失热区疏水肽段存在与否与ＤＭＤ发病密切相关。     

Antimutagenic activities of naturally occurring polyamines in Chinese hamster ovary cells in vitro

Spermine and spermidine, ubiquitous polyamines present in bacteria and animal cells, are also involved in cell growth. Since they interact with the double helix, they can stabilize the DNA molecule. Recent evidence of the antimutagenic and anticarcinogenic capacity of spermine has focused attention on the mechanism(s) by which such agents can protect cells from induced damages. In the present paper we show the ability of spermine and spermidine to decrease the level of sister chromatid exchanges induced in Chinese hamster ovary cells cultivated in vitro, by treating them with Psoralen + UVA irradiation (able to induce mainly monoadducts and DNA cross-links). Two different mechanisms of polyamine action can be invoked to explain the preservative activity of this class of agents.     

细胞色素P450调节剂对DNA加合物形成的影响

人羊膜上皮细胞ＦＬ系分别接触ａ－萘黄酮（０．６ｍｍｏｌ·Ｌ￣（－１））β－萘黄酮（２０ｐｍｏｌ·Ｌ￣（－１））２４ｈ后，再用苯并（ａ）芘［Ｂ（ａ）Ｐ，１０ｕｍｏｌ·Ｌ￣（－１）］处理２４ｈ，用３２Ｐ后标记技术测定以Ｂ（ａ）－ＤＮＡ加合物。结果发现，阳性对照组，ａ－萘黄酮预处理组及β－萘黄酮预处理组加合物的量分别为（加合物个数／１０’个核苷酸）：４．７±０．２（１００％），１．８±０．９（３８．３％），１６．０±２．２（３４０．１％）．该实验结果直接显示了纳胞色素Ｐ４５０调节剂对肿瘤发生影响的作用水平。亦为药物对致癌物代谢影响的研究提供了一种方法．     

Differential effects of luminol,nickel, and arsenite on the rejoining of ultraviolet light and alkylation-induced DNA breaks

When Chinese hamster ovary cells were treated with ultraviolet (UV) light or methyl methanesulfonate (MMS), a large number of DNA strand breaks could be detected by alkaline elution. These strand breaks gradually disappeared if the treated cells were allowed to recover in a drug-free medium. The presence of nickel or arsenite during the recovery incubation retarded the disappearance of UV-induced strand breaks, whereas the disappearance of MMS-induced strand breaks was retarded by the presence of arsenite or of luminol, a new inhibitor for poly(ADP-ribose) synthetase. Luminol, however, had no apparent effect on the repair of UV-induced DNA strand breaks, and nickel had no effect on the repair of MMS-induced DNA strand breaks. When UV- or MMS-treated cells were incubated in cytosine arabinofuranoside (AraC) plus hydroxyurea (HU), a large amount of low molecular weight DNA was detected by alkaline sucrose sedimentation. The molecular weight of these DNAs increased if the cells were further incubated in a drug-free medium. This rejoining of breaks in cells pretreated with UV plus AraC and HU was inhibited by nickel and by arsenite, but not by luminol. The rejoining of breaks in cells pretreated with MMS plus AraC and HU was inhibited by luminol and by arsenite, but not by nickel. These results suggest that different enzymes may be used in DNA resynthesis and/or ligation during the repairing of UV- and MMS-induced DNA strand breaks, and that nickel, luminol, and arsenite may have differential inhibitory effects on these enzymes. © 1994 Wiley-Liss, Inc.     

Fractionation of a chalone-containing preparation from Ehrlich's ascites tumor by high performance liquid chromatography

Department of Biology, Medico-Biological Faculty, and Applied Research Laboratory of Ecology, Toxicology, and Metabolism of Medicinal Preparations, attached to the Department of Biochemistry, Medico-Biological Faculty, N. I. Pirogov Second Moscow Medical Institute. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 112, No. 10, pp. 418–419, October, 1991.     

Rapid and simple isolation of DNA from agarose gels

Summary We present a simple method for the isolation of DNA from agarose gels that is economic, fast, and independent of electrical equipment. DNA fragments of up to 6 kb can be easily extracted within 5 min using a disposable plastic syringe and filter paper. Total extraction of DNA fragments between 10 and 20 kb in size is achieved by concentrating the DNA flushed from the gel in a DNA-binding column.     

Protective effect of interferon-α on the DNA- and RNA-degrading pathway in anti-Fas-antibody induced apoptosis

Aim: Fas membrane-associated polypeptide antigen is a receptor molecule responsible for apoptosis-mediated signals. In animal models of acute viral hepatitis, apoptosis of hepatocytes is mediated by Fas-death receptors; therefore, the aim of this study was to evaluate the effect of interferon (IFN)-alpha on apoptotic markers and nuclease activity against different coding and non-coding single and double stranded RNAs during Fas-induced liver apoptosis. Methods: An in vivo experiment was performed with simultaneous administration of anti-Fas (CD95) antibodies and IFN-alpha, and an in vitro experiment was performed in hepatocyte cultures treated with anti-Fas antibodies and IFN-alpha. Results: Detection of apoptosis using Annexin V-FITC/propidium iodide, Bcl-2 and Bax expression in hepatocyte cultures confirmed the appearance of early apoptotic events and progression toward late apoptosis after anti-Fas antibody treatment. IFN-alpha had a tendency to retard the apoptosis process in Fas-induced apoptosis by increasing the number of viable cells and decreasing the number of cells in late apoptosis, by increasing the percentage of Bcl-2 positive cells, by decreasing the percentage of Bax positive cells, and by decreasing the nuclease activity compared to the anti-Fas antibody treated group. Total DNA and RNA concentration was much reduced in the Fas group and DNA fragmentation assay provided evidence for increased DNA degradation. Enhanced nuclease activity against DNA, rRNA, poly(A), poly(C), poly(U), poly(I:C), and poly(A:U) was manifested in the anti-Fas antibody treated group, except for the inhibitory-bound alkaline RNase. Conclusions: The results demonstrate that the RNA-degrading pathway in Fas-induced apoptosis can accelerate the liberation of the latent enzyme from the inhibitor complex. IFN-alpha prevented enormous, Fas-ligand induced degradation of all the substrates used in this experimental study, most probably due to similarities in the signal transduction pathways. Investigations of death receptor-induced apoptosis may lead to novel treatment combinations for patients with acute or chronic liver diseases.     

长、短链探针以链延伸反应提高基因传感器检测MRSA灵敏度的实验研究

目的：利用链延伸反应的原理延长引物链以提高石英谐振式基因传感器表面的质量负载，从而提高传感器检测MRSA的灵敏度。方法：以不对称PCR的反应产物做为长链探针，人工合成的寡核苷酸片段为短链探针，在基因传感器阵列表面分别固定上金黄色葡萄球菌mecA和femA的长链及短链探针共4种探针片段，与相应的靶序列杂交后，加入Klenow酶，37℃进行链延伸反应1h。结果：长、短链探针均有效地固定了传感器表面。mecA,femA短链探针在链延伸反应前的检测灵敏度为0.5nmol/L，但经链延伸反应后检测灵敏提高到了0.05nmol/L；而长链探针却无法与相应的基因组靶序列发生杂交。结论：短链探针链延伸反应有效地提高了石英谐振式基因传感器的灵敏度，但该法不适用于链探针。     

大鼠腹裂模型肠管损伤的研究

目的研究先天性腹裂的肠管受损害情况，探讨该病术后并发症的原因。方法利用大鼠腹裂模型，运用组织学、生化学和免疫组织化学方法，分析腹裂胎鼠肠管的组织结构，DNA和蛋白质，细胞增生和凋亡等方面的改变。结果共获得腹裂胎鼠16只，对照胎鼠21只。与对照组相比，腹裂鼠肠管变短、充血水肿、粘连，肠壁表面纤维覆盖，壁内胶原沉积，DNA总量下降，蛋白质总量基本不变，细胞增生率下降，凋亡率上升。结论腹裂的肠管损伤是多方面的，是术后肠管运动和吸收功能异常的原因，大鼠的腹裂模型是对先天性腹裂的病因、病理等方面研究的合适工具。