中文摘要：

目的研究燃煤型地方性砷中毒患者甲基化能力与中毒症状间的关系。方法对贵州省某燃煤型地方性砷中毒病区进行调查,依据诊断标准确定患者,并将患者分为轻、中、重度3组。取尿样,测定尿中无机砷（iAs）、甲基砷（MMA）、二甲基砷（DMA）水平,计算总砷（tAs）水平,以一甲基化率（FMR）和二甲基化率（SMR）评价砷甲基化代谢能力。结果重度患者组iAs、MMA、DMA及tAs水平均显著高于轻度患者组;iAs、MMA及tAs水平均显著高于中度患者组。重度患者组SMR水平显著低于轻度及中度患者组。SMR与尿中MMA水平呈显著负相关（r=-0.793,P=0.001）,与砷中毒症状的轻重程度亦呈显著负相关（r=-0.439,P=0.046）。结论燃煤型地方性砷中毒患者SMR水平与尿中MMA水平显著负相关,重症患者的中毒损伤效应可能是由于患者SMR水平降低而引起MMA水平增高所致。

英文摘要：

Objective To study the correlation between methylation ability and symptom of patients from endemic arsenicosis of burning coal type.Methods atients from the areas of endemic arsenicosis of burning coal type was investigated.Urine samples were collected for the measurement of urinary inorganic arsenic（iAs）,monomethylated arsenic（MMA）,dimethylated arsenic（DMA）.Total arsenic（tAs）,the first methylation ratio（FMR） and the second methylation ratio（SMR） were calculated.Results The levels of iAs,MMA,DMA and tAs of the advanced group were significantly higher than those of the mild group;The levels of iAs,MMA and tAs of the advanced group were markedly higher than those of the moderate group.SMR level of the advanced group was significantly lower than those of the other groups.Significant negative correlations were found between the levels of SMR and MMA（r =-0.793,P=0.001）,and between SMR and the grades of symptoms（r =-0.439,P=0.046）.Conclusions SMR was significantly correlate with MMA in the patients,while the poisoning effects of the advanced patients might be due to the impaired SMR which will lead to the increase level of poisoning MMA.