Klaude M, Wernerman J, von der Decken A
Wenner-Gren Institute for Experimental Biology, University of Stockholm, Sweden.
Biochem Med Metab Biol. 1989 Jun;41(3):171-6. doi: 10.1016/0885-4505(89)90023-6.
O6-methylguanine-DNA methyltransferase removes methyl groups from the O-6 position of guanine in DNA previously alkylated by alkylating carcinogens. Thus, the protein facilitates restoration of the impaired DNA. The content of O6-methylguanine-DNA methyltransferase was assayed in circulating lymphocytes and the impact of surgical trauma investigated. Patients (n = 13) without metabolic diseases admitted for elective orthopedic surgery were used. The patients were allowed water and food postoperatively. Blood was taken before and 3 days following surgery and the circulating lymphocytes were isolated. Before surgery, the O6-methylguanine-DNA methyltransferase content determined in the cell extracts showed patient-specific variations. Following surgery, a significant decrease of the protein by 60% (from 609 to 243 fmole/mg of DNA) was observed. The intensity of surgical trauma was confirmed by the decrease in plasma albumin concentration and the increase in white blood cell counts. The surgical trauma might elicit its effect as either a change in turnover of O6-methylguanine-DNA methyltransferase or a release from the thymus of lymphocytes low in enzyme levels. In summary, the surgical trauma per se was the cause of the pronounced decrease in the O6-methylguanine-DNA methyltransferase seen here. Investigations on O6-methylguanine-DNA methyltransferase levels have an important relevance in studies on tumor-promoting agents inhaled and then taken up by the T lymphocytes of prospective proliferating capacity.
O6-甲基鸟嘌呤-DNA甲基转移酶可从先前被烷基化致癌物烷基化的DNA中鸟嘌呤的O-6位去除甲基基团。因此，该蛋白质有助于修复受损的DNA。我们检测了循环淋巴细胞中O6-甲基鸟嘌呤-DNA甲基转移酶的含量，并研究了手术创伤的影响。研究选取了13例因择期骨科手术入院且无代谢疾病的患者。术后允许患者饮水和进食。在手术前和手术后3天采集血液，分离循环淋巴细胞。手术前，在细胞提取物中测定的O6-甲基鸟嘌呤-DNA甲基转移酶含量显示出个体差异。手术后，观察到该蛋白质显著下降了60%（从609飞摩尔/毫克DNA降至243飞摩尔/毫克DNA）。血浆白蛋白浓度降低和白细胞计数增加证实了手术创伤的程度。手术创伤可能通过改变O6-甲基鸟嘌呤-DNA甲基转移酶的周转率或从胸腺释放酶水平低的淋巴细胞来发挥作用。总之，此处观察到的手术创伤本身就是O6-甲基鸟嘌呤-DNA甲基转移酶显著下降的原因。对O6-甲基鸟嘌呤-DNA甲基转移酶水平的研究在对吸入后被具有潜在增殖能力的T淋巴细胞摄取的肿瘤促进剂的研究中具有重要意义。
