Kumar P M, Fox B W
Br J Cancer. 1974 Jun;29(6):447-61. doi: 10.1038/bjc.1974.97.
MtDNA was extracted by a phenol method from transplanted and primary DAB induced hepatomata in male Wistar rats, normal rat liver, spontaneous human tumours (2 Wilm's tumours, one neuroblastoma and one adrenal carcinoma), as well as 2 specimens of normal human kidney, BNU induced "leukaemias" in mice and CHO fibroblasts in monolayer culture. The proportion of monomers, catenated dimers and oligomers, open dimers and small circles was determined by electron microscopy of the fractions comprising lower and middle DNA bands in a CsCl-EthBr gradient. Tumours were compared where possible with their normal tissue of origin. Open dimers were found in 2 Wilm's tumours and their attached "normal-looking" kidney tissue but not in normal, non-malignant kidney or any other tissue studied. In Wilm's tumours, the occurrence of open dimers is far from being an all-or-none phenomenon. Malignancy produced little change in the relative proportions of catenated dimers and oligomers in the tissues studied. Small circles were found associated with mtDNA from every tissue. Tumour mtDNA was not more heterogeneous in length than monomers from the corresponding normal tissue, neither was the mean length of tumour mtDNA significantly different from its corresponding normal mtDNA.
采用酚法从雄性Wistar大鼠移植的和原发性二乙基亚硝胺诱导的肝癌、正常大鼠肝脏、人类自发性肿瘤（2例肾母细胞瘤、1例神经母细胞瘤和1例肾上腺癌）以及2例正常人类肾脏标本、BNU诱导的小鼠“白血病”和单层培养的中国仓鼠卵巢（CHO）成纤维细胞中提取线粒体DNA（mtDNA）。通过对氯化铯-溴化乙锭梯度中低、中DNA条带的组分进行电子显微镜观察，确定单体、连环二聚体和寡聚体、开环二聚体和小环的比例。尽可能将肿瘤与其起源的正常组织进行比较。在2例肾母细胞瘤及其附着的“外观正常”的肾脏组织中发现了开环二聚体，但在正常的非恶性肾脏或其他任何研究的组织中均未发现。在肾母细胞瘤中，开环二聚体的出现远非全或无的现象。恶性肿瘤对所研究组织中连环二聚体和寡聚体的相对比例几乎没有影响。在每个组织的mtDNA中都发现了小环。肿瘤mtDNA的长度异质性并不比相应正常组织的单体更大，肿瘤mtDNA的平均长度与其相应的正常mtDNA也没有显著差异。
