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.

中文翻译：

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pH值对吸烟者和非吸烟者尿液致突变性的影响。

吸烟是膀胱癌的主要危险因素。香烟烟雾中的某些化学物质（例如芳香胺）在肝脏中代谢，并以葡糖醛酸苷或乙酰基结合物的形式在尿中排出。这些代谢物经过pH介导的活化性反应性亚硝酸根离子活化，可能导致DNA加合物，从而在某些吸烟者中引发膀胱肿瘤发生。我们假设改变吸烟者尿液的pH值将影响这些代谢物的诱变结果。从吸烟者（n = 11）和非吸烟者（n = 11）收集过夜样品，并保存在-70°C。将每个尿液样品调节至中性（7.0），碱性（8.2）和酸性（5.5）pH。使用鼠伤寒沙门氏菌菌株YG1024微悬浮液试验，通过Ames试验评估诱变活性。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）。两组中，在不同pH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。