Pincheira J, Rodriguez M, Bravo M, Navarrete M H, Lopez-Saez J F
Department of Cellular Biology and Genetics, University of Chile, Santiago.
Clin Genet. 1994 Jan;45(1):25-31. doi: 10.1111/j.1399-0004.1994.tb03985.x.
Lymphocytes from both Down syndrome (DS) patients and age-matched control donors have been investigated to identify a possible disturbance in chromosomal G2 repair. Analyses of caffeine treatments during G2 have shown that the frequency of chromosomal aberrations is higher in DS lymphocytes than in normal lymphocytes. Likewise, G2 duration is longer in DS cells than in normal cells. In both control and DS lymphocytes, caffeine treatments increase the frequencies of chromatid breakages and decrease the average of G2 duration. The reversal of the caffeine potentiation effect by adenosine and niacinamide is higher in DS cells than in normal cells. Furthermore, ATP content per cell in DS lymphocytes is one third of that estimated in normal lymphocytes. The increase of ATP level produced by adenosine or niacinamide generally correlates with the reversal of the caffeine effect on chromosome aberrations. Under the experimental conditions tested, a good negative exponential correlation between ATP level and chromosome aberrations has been detected in both normal and DS lymphocytes which were or were not X-irradiated. Finally, we postulate a decrease in G2 repair capability of DS lymphocytes caused by a low availability of ATP and/or some other factor correlating with it.
对唐氏综合征（DS）患者和年龄匹配的对照供体的淋巴细胞进行了研究，以确定染色体G2修复中可能存在的干扰。对G2期咖啡因处理的分析表明，DS淋巴细胞中染色体畸变的频率高于正常淋巴细胞。同样，DS细胞的G2期持续时间比正常细胞长。在对照淋巴细胞和DS淋巴细胞中，咖啡因处理都会增加染色单体断裂的频率，并缩短G2期的平均持续时间。腺苷和烟酰胺对咖啡因增强效应的逆转在DS细胞中比在正常细胞中更明显。此外，DS淋巴细胞中每个细胞的ATP含量是正常淋巴细胞估计值的三分之一。腺苷或烟酰胺产生的ATP水平升高通常与咖啡因对染色体畸变的影响的逆转相关。在测试的实验条件下，在未受或受过X射线照射的正常淋巴细胞和DS淋巴细胞中，均检测到ATP水平与染色体畸变之间存在良好的负指数相关性。最后，我们推测DS淋巴细胞的G2修复能力下降是由ATP可用性低和/或与之相关的其他一些因素引起的。
