School of Pharmacy at MCV Campus, Virginia Commonwealth University, Smith Building, Room 356C, 410 N 12th Street, Richmond, VA 23298-0533, USA.
Environ Toxicol Pharmacol. 2003 Jan;13(1):21-7. doi: 10.1016/s1382-6689(02)00125-4.
Cigarette smoking is a major risk factor for bladder cancer. Some chemicals from cigarette smoke e.g. aromatic amines, are metabolized in the liver and excreted in urine as either glucuronide or acetyl conjugates. These metabolites undergo pH mediated activation to reactive nitreneum ions that may lead to DNA adducts, initiating bladder tumorigenesis in some smokers. We hypothesize that changing the pH of smokers urine will impact the mutagenic outcome of these metabolites. Overnight samples were collected from smokers (n=11) and nonsmokers (n=11) and stored at -70°C. Each urine sample was adjusted to neutral (7.0), basic (8.2) and acidic (5.5) pH. Mutagenic activity was assessed with the Ames test utilizing the Salmonella Typhimurium strain YG1024 microsuspension assay. Urine from smokers was significantly mutagenic compared with nonsmokers (P<0.001). In both the groups, there was no difference between urine adjusted at different pH (P>0.05). We conclude that changing the pH of smokers urine might not affect their subsequent risk for bladder cancer.
吸烟是膀胱癌的主要危险因素。香烟烟雾中的一些化学物质，如芳香胺，在肝脏中代谢，然后以葡萄糖醛酸或乙酰结合物的形式从尿液中排出。这些代谢物在 pH 介导下发生激活，形成反应性亚硝胺离子，可能导致 DNA 加合物，从而引发一些吸烟者的膀胱癌发生。我们假设改变吸烟者尿液的 pH 值会影响这些代谢物的致突变结果。收集了吸烟者（n=11）和不吸烟者（n=11）的过夜尿液样本，并储存在-70°C 下。每个尿液样本的 pH 值分别调整为中性（7.0）、碱性（8.2）和酸性（5.5）。利用沙门氏菌 Typhimurium 菌株 YG1024 微悬浮液测定法，通过 Ames 试验评估了致突变活性。与不吸烟者相比，吸烟者的尿液具有明显的致突变性（P<0.001）。在这两个组中，不同 pH 值下调整的尿液之间没有差异（P>0.05）。我们得出结论，改变吸烟者尿液的 pH 值可能不会影响他们随后患膀胱癌的风险。
