内蒙古不同浓度砷暴露人群尿砷代谢产物研究

目的 测定内蒙古地区饮用高砷水人群尿砷代谢产物，探讨不同人群砷代谢的特点。方法 采用氢化物发生原子吸收分光光度法检测尿中不同形态的砷代谢产物。结果 2个暴露组人群尿中无机砷（iAs，inorganic arserlic）、甲基砷（MMA，monomethylarsine）、二甲基砷（DMA．dimethylarsine）和总砷（TAs，total arserlic）均高于对照组（P〈0．05）；同样砷暴露水平下，尿中各形态砷含量及其相对比在不同性别问的差异均无统计学意义（P〉0．05），儿童DMA／MMA和DMA％高于成人（P〈0．05），MMA％低于成人（P〈0．05）；2个暴露组儿童、成人分别与对照组比较，暴露组MMA／ias、DMA／MMA、DMA／iAs、DMA％显降低（P〈0．05），而iAs％、MMA％显增高（P〈0．05）；高暴露组与低暴露组相比，儿童DMA／MMA、DMA／iAs、DMA％显增高（P〈0．05），iAs％、MMA％显降低（P〈0．05）。结论 相同砷暴露水平下，男女对砷的甲基化能力无差别，儿童二甲基化能力高于成人。高砷暴露可能降低人群对砷的生物甲基化能力。[编按]     

The prevalence of subjective symptoms after exposure to arsenic in drinking water in Inner Mongolia,China

BACKGROUND: In Inner Mongolia, China, more than 300,000 people are chronically exposed to arsenic via their drinking water. We have previously reported that the prevalence of arsenical dermatosis was as high as 40% in the Hetao Plain area. However, the association between exposure to arsenic in drinking water and adverse health effects has not been fully examined. The purpose of this study was to examine the association between exposure to arsenic and prevalence of subjective symptoms. METHODS: A cross-sectional study was carried out in 431 residents of an arsenic-affected village and 189 residents of an arsenic-free village in 1996. Health-related interviews and physical examinations were conducted. The odds ratio for each subjective symptom was estimated, comparing residents of arsenic-free and affected villages. RESULTS: An arsenic level of 50+ microg/L was found in 90.6% of wells in the arsenic-affected village. Adjusted odds ratios of subjective symptoms, including coughs (odds ratio [OR] = 12.8, 95% confidence interval [CI]: 6.4-25.6), stomachaches (OR = 5.8, 95% CI: 3.6-9.4), palpitations (OR = 3.6, 95% CI: 1.5-8.2), urination problems (OR = 14.7, 95% CI: 3.3-65.5) and spontaneous abortions (OR = 2.7, 95% CI: 0.8-8.4), were markedly higher amongst residents of the arsenic-affected village, including those without arsenic dermatosis. CONCLUSIONS: The present study shows a high prevalence of subjective symptoms amongst residents of an arsenic-affected village. Symptoms occurred in people with and without arsenic dermatosis. Our findings suggest that symptoms other than dermatosis should be considered when a clinical diagnosis of arsenic toxicosis is made.     

Urinary arsenic metabolites of subjects exposed to elevated arsenic present in coal in Shaanxi Province, China

In contrast to arsenic (As) poisoning caused by naturally occurring inorganic arsenic-contaminated water consumption, coal arsenic poisoning (CAP) induced by elevated arsenic exposure from coal combustion has rarely been reported. In this study, the concentrations and distributions of urinary arsenic metabolites in 57 volunteers (36 subjects with skin lesions and 21 subjects without skin lesions), who had been exposed to elevated levels of arsenic present in coal in Changshapu village in the south of Shaanxi Province (China), were reported. The urinary arsenic species, including inorganic arsenic (iAs) [arsenite (iAsIII) and arsenate (iAsV)], monomethylarsonic acid (MMAV) and dimethylarsinic acid (DMAV), were determined by high-performance liquid chromatography (HPLC) combined with inductively coupled plasma mass spectroscopy (ICP-MS). The relative distributions of arsenic species, the primary methylation index (PMI=MMAV/iAs) and the secondary methylation index (SMI=DMAV/MMAV) were calculated to assess the metabolism of arsenic. Subjects with skin lesions had a higher concentration of urinary arsenic and a lower arsenic methylation capability than subjects without skin lesions. Women had a significantly higher methylation capability of arsenic than men, as defined by a higher percent DMAV and SMI in urine among women, which was the one possible interpretation of women with a higher concentration of urinary arsenic but lower susceptibility to skin lesions. The findings suggested that not only the dose of arsenic exposure but also the arsenic methylation capability have an impact on the individual susceptibility to skin lesions induced by coal arsenic exposure.     

渔村与砷暴露地区居民尿砷代谢产物检测比较

目的 测定渔村居民和饮水型砷暴露地区人群尿中各种形态砷和尿总砷(TAs)。方法 选取饮水型砷暴露地区〔口肯板村水砷浓度为0.16 mg/L;乃莫板村水砷浓度为0.09 mg/L;塔布塞村(对照组)饮用水砷浓度<0.01 mg/L〕和渔村居民。采用氢化物发生原子吸收分光光度法检测尿中各形态砷代谢物和TAs含量。结果 TAs含量渔村居民明显低于0.16 mg/L暴露组,高于对照组(P<0.05),与0.09 mg/L暴露组差异无统计学意义;渔村居民尿无机砷(iAs)含量明显低于0.09和0.16 mg/L暴露组(P<0.05);尿甲基砷(MMA)含量同尿二甲基砷(DMA)含量,各组之间差异均有统计学意义(P<0.05);渔村居民尿iAs百分比明显低于对照组、0.09和0.16 mg/L暴露组(P<0.05);尿MMA百分比同尿iAs百分比;各组尿DMA百分比差异均有统计学意义(P<0.05);渔村居民特异性的检测出尿三甲胺(TMA)。结论 人群尿总砷水平受食用海产品等因素影响,不能单独作为砷暴露指标,应使用分析性方法来区分砷复合物中无机砷和有机砷的代谢产物。     

Biomonitoring of perfluorinated compounds in children and adults exposed to perfluorooctanoate-contaminated drinking water

OBJECTIVE: 40,000 residents in Arnsberg, Germany, had been exposed to drinking water contaminated with perfluorinated compounds (PFCs). Internal exposure of the residents of Arnsberg to six PFCs was assessed in comparison with reference areas. DESIGN AND PARTICIPANTS: One hundred seventy children (5-6 years of age), 317 mothers (23-49 years), and 204 men (18-69 years) took part in the cross-sectional study. MEASUREMENTS: Individual consumption of drinking water and personal characteristics were assessed by questionnaire and interview. Perfluorooctanoate (PFOA), perfluorooctanesulfonate (PFOS), perfluorohexanoate, perfluorohexanesulfonate (PFHxS), perfluoropentanoate, and perfluorobutanesulfonate (PFBS) in blood plasma and PFOA/PFOS in drinking water samples were measured by solid-phase extraction, high-performance liquid chromatrography, and tandem mass spectrometry detection. RESULTS: Of the various PFCs, PFOA was the main compound found in drinking water (500-640 ng/L). PFOA levels in blood plasma of residents living in Arnsberg were 4.5-8.3 times higher than those for the reference population (arithmetic means Arnsberg/controls: children 24.6/5.2 microg/L, mothers 26.7/3.2 microg/L, men 28.5/6.4 microg/L). Consumption of tap water at home was a significant predictor of PFOA blood concentrations in Arnsberg. PFHxS concentrations were significantly increased in Arnsberg compared with controls (p < 0.05). PFBS was detected in 33% of the children, 4% of the women, and 13% of the men in Arnsberg compared with 5%, 0.7%, and 3%, respectively, in the reference areas (p < 0.05). Regression analysis showed that age and male sex were significant predictors of PFOS, PFOA, and PFHxS; associations of other regressors (diet, body mass index) varied among PFCs. CONCLUSIONS: PFC concentrations in blood plasma of children and adults exposed to PFC-contaminated drinking water were increased 4- to 8-fold compared with controls.     

Family correlations of arsenic methylation patterns in children and parents exposed to high concentrations of arsenic in drinking water

We investigated the evidence of a familial contribution to urinary methylation patterns in families ingesting arsenic in drinking water. Arsenic methylation can be assessed by measuring urinary levels of inorganic arsenic (InAs) and its methylated metabolites, monomethylarsonate (MMA), and dimethylarsinate (DMA). Methylation activity is reflected in the ratios: InAs/methylated arsenic (InAs/metAs) and MMA/DMA. Eleven families from Chile were selected because of their long-term exposure to very high levels of arsenic in drinking water (735-762 microg/L). Each family consisted of a father, a mother, and two children. We measured urinary arsenic and its methylated metabolites for each participant (n = 44). The intraclass correlation coefficients showed that 13-52% of the variations in the methylation patterns were from being a member of a specific family. Family correlations were calculated for father-mother, parent-child, and sibling-sibling pairs. Methylation patterns correlated strongly between siblings [r = 0.78 for InAs/metAs, 95% confidence interval (CI), 0.34-0.94; r = 0.82 for MMA/DMA, 95%CI, 0.43-0.95] compared to lower correlations in father-mother pairs (r = 0.18, r = -0.01, respectively), after adjustment for total urinary arsenic, age, and sex. Family correlations were not notably altered when adjustments were made for specific blood micronutrients (methionine, homocysteine, folate, vitamin B6, selenium, and vitamin B12 potentially related to methylation. We also report on a family pedigree with high prevalence of arsenic-induced effects. Participants from this family had low InAs/metAs values, which is consistent with increased toxicity of trivalent methylated arsenic species. Despite our small sample size, we observed that methylation patterns aggregate in families and are correlated in siblings, providing evidence of a genetic basis for the variation in arsenic methylation. Larger studies with more extensive pedigrees will need to be conducted to confirm these findings.     

Distribution of urinary selenium and arsenic among pregnant women exposed to arsenic in drinking water

Inorganic arsenic (In-As) is a well-known toxicant and carcinogen found naturally in surface and groundwater around the world. Exposure can cause skin lesions, adverse reproductive outcomes, and cancer. There are two main pathways of arsenic (As) metabolism in humans: the reduction reactions, and the oxidative methylation reactions, where methyl groups are attached to As compounds to form monomethylarsenate (MMA) and dimethylarsenate (DMA). MMA, DMA, and In-As are excreted in urine. Urinary levels of another metalloid, selenium (Se), have recently been shown to be associated with increased As excretion and altered metabolite distribution. This study investigates this association, using data collected in a larger prospective study of arsenic and reproductive effects in Chile. This analysis included 93 pregnant women from Antofagasta. Data on demographic, behavioral, and other characteristics were obtained via interviews conducted by trained midwives, and spot urine samples were analyzed for As and Se concentration using inductively coupled plasma-mass spectrometry (ICP-MS). Urinary Se levels were found to be correlated with urinary As levels in bivariate analysis (r = 0.68, P < 0.01). Multiple linear regression analyses revealed that higher urinary Se levels were associated with increased urinary As excretion, increased %DMA, and decreased %In-As. The results of this study suggest that in populations exposed to arsenic, Se intake may be correlated with urinary As excretion, and may alter As methylation.     

Chromosome studies in human subjects chronically exposed to arsenic in drinking water

A two-year study was carried out on human subjects of various ages and backgrounds who had been drinking water containing more than 0.05 mg/liter (0.05 ppm) arsenic for a period of at least five years. The main aim was to correlate the frequency of chromosome aberrations and sister chromatid exchanges in the lymphocytes with the amount of arsenic in the water. In addition, we explored the incidence of skin cancer, fetal wastage, and genetic or developmental abnormalities. Several other variables—eg, coffee, wine, and cigarette consumption; sex, residence (rural vs urban); and exposure to chemicals, smelters, or pesticides—were also taken into consideration. The data on chromosome aberrations (104 exposed and 86 control individuals) and on sister chromatid exchanges (98 exposed and 83 control individuals) did not show that arsenic at concentrations used by our population (>0.05 mg/liter) has any effect on these parameters. Similarly, no other health effects of arsenic at these concentrations were found.     

Neurosensory effects of chronic exposure to arsenic via drinking water in Inner Mongolia: I. Signs, symptoms and pinprick testing

This study was designed to assess the effects of exposure to arsenic in drinking water on neurosensory function. A questionnaire including neurological signs and symptoms and a brief neurological exam consisting of pinprick testing of the arms and legs and knee-jerk test were administered to 321 residents of the Bamen region of Inner Mongolia, China. Arsenic in water was measured by hydride generation atomic fluorescence. Participants were divided into three exposure groups--low (non-detectible-20), medium (100-300) and high (400-700 microg/I) arsenic. Significant group differences were observed in pinprick scores for all four limbs. Results indicate that arsenic alters pinprick (pain) thresholds at well-water concentrations as low as 400 microg/l, well below the 1000 microg/l threshold for neurological effect specified by NRC (1999). Regression models suggest that a 50% increase in pinprick score is associated with a 71-159 ppb increase in arsenic concentration.     

Neurosensory effects of chronic exposure to arsenic via drinking water in Inner Mongolia: II. Vibrotactile and visual function

This study was designed to assess the effects of exposure to arsenic in drinking water on visual and vibrotactile function in residents of the Bamen region of Inner Mongolia, China. Arsenic was measured by hydride generation atomic fluorescence. 321 participants were divided into three exposure groups- low (non-detectable-20), medium (100-300) and high (400-700 microg/l) arsenic in drinking water (AsW). Three visual tests were administered: acuity, contrast sensitivity and color discrimination (Lanthony's Desaturated 15 Hue Test). Vibration thresholds were measured with a vibrothesiometer. Vibration thresholds were significantly elevated in the high exposure group compared to other groups. Further analysis using a spline regression model suggested that the threshold for vibratory effects is between 150-170 microg/l AsW. These findings provide the first evidence that chronic exposure to arsenic in drinking water impairs vibrotactile thresholds. The results also indicate that arsenic affects neurological function well below the 1000 microg/I concentration reported by NRC (1999). No evidence of arsenic-related effects on visual function was found.     

Urinary arsenic species, toenail arsenic, and arsenic intake estimates in a Michigan population with low levels of arsenic in drinking water

The large disparity between arsenic concentrations in drinking water and urine remains unexplained. This study aims to evaluate predictors of urinary arsenic in a population exposed to low concentrations (≤50?μg/l) of arsenic in drinking water. Urine and drinking water samples were collected from a subsample (n=343) of a population enrolled in a bladder cancer case-control study in southeastern Michigan. Total arsenic in water and arsenic species in urine were determined using ICP-MS: arsenobetaine (AsB), arsenite (As[III]), arsenate (As[V]), methylarsenic acid (MMA[V]), and dimethylarsenic acid (DMA[V]). The sum of As[III], As[V], MMA[V], and DMA[V] was denoted as SumAs. Dietary information was obtained through a self-reported food intake questionnaire. Log(10)-transformed drinking water arsenic concentration at home was a significant (P<0.0001) predictor of SumAs (R(2)=0.18). Associations improved (R(2)=0.29, P<0.0001) when individuals with less than 1?μg/l of arsenic in drinking water were removed and further improved when analyses were applied to individuals who consumed amounts of home drinking water above the median volume (R(2)=0.40, P<0.0001). A separate analysis indicated that AsB and DMA[V] were significantly correlated with fish and shellfish consumption, which may suggest that seafood intake influences DMA[V] excretion. The Spearman correlation between arsenic concentration in toenails and SumAs was 0.36 and between arsenic concentration in toenails and arsenic concentration in water was 0.42. Results show that arsenic exposure from drinking water consumption is an important determinant of urinary arsenic concentrations, even in a population exposed to relatively low levels of arsenic in drinking water, and suggest that seafood intake may influence urinary DMA[V] concentrations.     

Prevalence of chronic diseases in adults exposed to arsenic-contaminated drinking water

Inorganic arsenic is naturally occurring in groundwaters throughout the United States. This study investigated arsenic exposure and self-report of 9 chronic diseases. We received private well-water samples and questionnaires from 1185 people who reported drinking their water for 20 or more years. Respondents with arsenic levels of 2 microg/L or greater were statistically more likely to report a history of depression, high blood pressure, circulatory problems, and bypass surgery than were respondents with arsenic concentrations less than 2 microg/L.     

Methylation study of a population environmentally exposed to arsenic in drinking water.

Methylation is considered the detoxification pathway for inorganic arsenic (InAs), an established human carcinogen. Urinary speciation analysis is used to assess the distribution of metabolites [monomethylarsonate (MMA), dimethylarsinate (DMA), and unmethylated arsenic (InAs)], as indicators of methylation capacity. We conducted a large biomarker study in northern Chile of a population chronically exposed to high levels of arsenic in drinking water. We report the results of the methylation study, which focused on the effects of exposure and other variables on the percent InAs, MMA, DMA, and the ratio of MMA to DMA in urine. The study consisted of 122 people in a town with arsenic water levels around 600 micrograms/l and 98 participants in a neighboring town with arsenic levels in water of about 15 micrograms/l. The corresponding mean urinary arsenic levels were 580 micrograms/l and 60 micrograms/l, of which 18.4% and 14.9% were InAs, respectively. The main differences were found for MMA:DMA; exposure, smoking, and being male were associated with higher MMA:DMA, while longer residence, Atacameño ethnicity, and being female were associated with lower MMA:DMA. Together, these variables explained about 30% of the variability in MMA:DMA. Overall, there was no evidence of a threshold for methylation capacity, even at very high exposures, and the interindividual differences were within a much wider range than those attributed to the variables investigated. The differences in percent InAs were small and within the ranges of other studies of background exposure levels. The biological significance of MMA:DMA, which was more than 1.5 times greater in the exposed group, and its relationship to sex, length of exposure, and ethnicity need further investigation because its relevance to health risk is not clear.     

Decreased intelligence in children and exposure to fluoride and arsenic in drinking water

Recent evidence suggests that fluoride (F) and arsenic (As) may adversely affect intelligence quotient (IQ) scores. We explore the association between exposure to F and As in drinking water and intelligence in children. Three rural communities in Mexico with contrasting levels of F and As in drinking water were studied: Moctezuma (F 0.8+/-1.4 mg/L; As 5.8+/-1.3 microg/L); Salitral (F 5.3+/-0.9 mg/L; As 169+/-0.9 microg/L) and 5 de Febrero (F 9.4+/-0.9 mg/L; As 194+/-1.3 microg/L). The final study sample consisted of 132 children from 6 to 10 years old. After controlling for confounders, an inverse association was observed between F in urine and Performance, Verbal, and Full IQ scores (beta values = -13, -15.6, -16.9, respectively). Similar results were observed for F in drinking water (beta values = -6.7, -11.2, -10.2, respectively) and As in drinking water (beta values= -4.30, -6.40, -6.15, respectively). The p-values for all cases were < 0.001. A significant association was observed between As in urine and Full IQ scores (beta = -5.72, p = 0.003). These data suggest that children exposed to either F or As have increased risks of reduced IQ scores.     

Urinary protein excretion in humans exposed to arsenic and cadmium

OBJECTIVE: In mice, the renal toxicity of arsenic (As) and cadmium (Cd) has been shown to be exacerbated by the simultaneous administration of both elements. To verify the existence of such an interaction in humans, cohorts slightly (Belgian) and moderately (Chinese) exposed to both elements were examined. METHODS: Biological indicators of exposure (Cd in urine and in blood; As in urine) and renal effect parameters (retinol binding protein (RBP); beta(2)-microglobulin (beta(2)M); albumin (ALB); N-acetyl-beta-glucosaminidase (NAG) in urine) were determined and their relationships studied by multiple regression analyses. RESULTS: Changes in renal effect parameters could be ascribed to Cd body burden. RBP and beta(2)M urinary concentration were influenced by exposure to As only in Chinese women, directly and in interaction with Cd exposure. CONCLUSION: A synergistic action of As on the tubular effects of Cd is observed in women moderately exposed to these elements and leads to RBP urinary excretion slightly above normal values.     

谷胱甘肽与亚硒酸钠对饮水砷暴露小鼠体内砷代谢的影响

目的 探讨给予外源性谷胱甘肽(GSH)和亚硒酸钠(sodium selenite)对饮水砷暴露小鼠肝、肾和血中砷代谢的影响.方法 将小鼠按数字表法随机分为对照组、单纯染砷组(砷组)、GSH干预组(GSH组)与亚硒酸钠干预组(硒组),每组各8只小鼠.小鼠以自由饮水方式共染砷4周,饮水砷浓度为50 mg/L.从第4周起,染砷同时腹腔注射GSH(600 mg/kg体重)或亚硒酸钠(1 mg/kg体重)进行干预,共干预7 d.末次注射后处死小鼠,取其肝、肾和血组织样品.采用氢化物发生-超低温捕集-原子吸收分光光度法,分别检测小鼠肝、肾和血中无机砷(iAs)、一甲基胂(MMA)和二甲基胂(DMA)的含量.结果 GSH组小鼠肝中DMA含量[(233.76±60.63)ng/g湿重]及血中DMA含量[(88.52±30.86)ng/g湿重]和总砷(TAs)含量[(162.32±49.45)ng/g湿重]高于相对应的砷组小鼠[(218.36±42.71)、(45.32±12.19)、(108.51±18.00)ng/g湿重](q值分别为3.06、6.40、10.72,P＜0.05).GSH组小鼠肝中砷一甲基化率(PMI,0.65±0.05)和二甲基化率(SMI,0.55±0.05)及血中PMI(0.85±0.07)与砷组小鼠相对应的甲基化率(0.58±0.06、0.44±0.09、0.54±0.11)比较升高(q值分别为3.75、5.26、4.21.P＜0.05).硒组与砷组各项指标间差异无统计学意义.结论 给予外源性GSH可以促进iAs在小鼠体内甲基化代谢,从而降低其对机体的毒性损伤.而亚硒酸钠则无明显作用.     

Urinary trivalent methylated arsenic species in a population chronically exposed to inorganic arsenic

Chronic exposure to inorganic arsenic (iAs) has been associated with increased risk of various forms of cancer and of noncancerous diseases. Metabolic conversions of iAs that yield highly toxic and genotoxic methylarsonite (MAsIII) and dimethylarsinite (DMAsIII) may play a significant role in determining the extent and character of toxic and cancer-promoting effects of iAs exposure. In this study we examined the relationship between urinary profiles of MAsIII and DMAsIII and skin lesion markers of iAs toxicity in individuals exposed to iAs in drinking water. The study subjects were recruited among the residents of an endemic region of central Mexico. Drinking-water reservoirs in this region are heavily contaminated with iAs. Previous studies carried out in the local populations have found an increased incidence of pathologies, primarily skin lesions, that are characteristic of arseniasis. The goal of this study was to investigate the urinary profiles for the trivalent and pentavalent As metabolites in both high- and low-iAs-exposed subjects. Notably, methylated trivalent arsenicals were detected in 98% of analyzed urine samples. On average, the major metabolite, DMAsIII, represented 49% of total urinary As, followed by DMAsV (23.7%), iAsV (8.6%), iAsIII (8.5%), MAsIII (7.4%), and MAsV (2.8%). More important, the average MAsIII concentration was significantly higher in the urine of exposed individuals with skin lesions compared with those who drank iAs-contaminated water but had no skin lesions. These data suggest that urinary levels of MAsIII, the most toxic species among identified metabolites of iAs, may serve as an indicator to identify individuals with increased susceptibility to toxic and cancer-promoting effects of arseniasis.     

Low-level arsenic excretion in breast milk of native Andean women exposed to high levels of arsenic in the drinking water

Objective: To investigate the excretion of arsenic in breast milk of lactating native Andean women living in a village in northwestern Argentina with high concentrations of arsenic in the drinking water (about 200 μg/l) and to assess the exposure of children to arsenic during the very first period of life. Methods: The study included ten lactating women and two nursing babies. Hydride-generation atomic absorption spectrometry (HG-AAS) was used to determine the concentration of arsenic in samples of human milk, drinking water, blood, and urine. Results: The concentrations of arsenic detected in maternal blood (total arsenic) and urine (metabolites of inorganic arsenic) were high, averaging 10 and 320 μg/l, respectively. In subjects without known exposure to arsenic the average concentrations found in blood and urine are 1–2 and about 10 μg/l, respectively. The metabolites of inorganic arsenic constituted more than 80% of the total arsenic in the urine, which shows that inorganic arsenic was the main form of arsenic ingested. The average concentration of arsenic detected in human milk was 2.3 μg/kg fresh weight (range 0.83–7.6 μg/kg). Although data on background levels of arsenic in human breast milk are scarce, the present concentrations seem to be slightly elevated. However, considering the high levels of arsenic exposure in the mothers, the total arsenic concentrations measured in human milk were low. In concordance with the low concentrations of arsenic found in the milk, the concentrations of arsenic metabolites measured in the urine of two of the nursing babies were low: 17 and 47 μg/l, respectively. Conclusions: The low concentrations of arsenic detected in the breast milk and urine of the two nursing babies in relation to the high level of maternal exposure to arsenic indicate that inorganic arsenic is not excreted in breast milk to any significant extent. This is a very important reason for long breast-feeding periods. Received: 27 February 1997 / Accepted: 6 June 1997     

饮水型地方性砷中毒患者皮肤损伤与甲基化代谢关系

目的 探讨饮水型砷中毒患者皮肤损伤与甲基化代谢能力的关系。方法 依据诊断标准对某饮水型砷中毒病区患者症状进行分级,测定血中无机砷(iAs)、甲基砷(MMA)、二甲基砷(DMA)含量并计算百分比(iAs%、MMA%、DMA%),以iAs、MMA及DMA的总和表示总砷(tAs)水平,以(MMA+DMA)/tAs及DMA/(MMA+DMA)分别计算一甲基化率(FMR)和二甲基化率(SMR)水平。结果 患者血中形态砷和甲基化指标水平在性别间差异无统计学意义(P>0.05);轻、中、重度患者FMR水平差异无统计学意义(P>0.05);中度及重度患者SMR水平[(0.36±0.11)、(0.37±0.08)]均低于轻度患者(0.48±0.11),MMA%[(0.50±0.06)、(0.52±0.03)]均高于轻度患者(0.41±0.09);SMR水平与患者皮肤损伤症状等级之间呈负相关(r=-0.429,P<0.05)。结论 SMR水平下降及MMA%水平增高与砷性皮肤损伤关系密切。