Lipid peroxidation and concentration of glutathione in erythrocytes from workers exposed to lead.

Lipoperoxide concentration in erythrocytes from workers occupationally exposed to lead (mean blood lead concentration 57.1 (SD 17.6) micrograms/dl) was significantly higher than that in controls. It was not different in plasma from the two groups. The activity of superoxide dismutase (SOD) and catalase in erythrocytes from workers exposed to lead was significantly lower than that of control subjects. The effect of lead was also seen in the glutathione concentration of erythrocytes from lead exposed workers, which was reduced to 69% of that found in erythrocytes from control workers. The increase in methaemoglobin content of erythrocytes from workers exposed to lead was less than expected and not significantly different from that of controls. A positive correlation between lipoperoxide concentration in erythrocytes and lead concentration in blood and a negative correlation between glutathione concentration in erythrocytes and blood lead concentration were found. Incubation of erythrocytes for 24 hours at 37 degrees C in the presence of lead (100 micrograms/dl) produced no changes in glutathione and lipoperoxide concentrations, although there was inhibition of activity of SOD (14.3%), catalase (10.1%), and glutathione peroxidase (35.1%). A similar experiment with heparinised whole blood showed increased haemolysis with no changes in membrane lipid peroxidation of erythrocytes. It is postulated that the lowered concentration of glutathione and decreased activity of SOD, catalase, and glutathione peroxidase in erythrocytes from workers exposed to lead may play a part in the increased membrane lipid peroxidation. Furthermore, the results suggest the possibility that leucocytes, or platelets, or both, may induce haemolysis in the presence of lead.     

Lipid peroxidation and antioxidative enzyme activity in erythrocytes of workers occupationally exposed to aluminium

Current research indicates that lipid peroxidation could have a role in aluminium toxicity. The aim of this study was to asses lipid peroxidation and antioxidative enzyme activity in erythrocytes of workers occupationally exposed to aluminium. We investigated a group of 59 workers (Al group) exposed to aluminium fumes (contamination factor F=8.07 to 13.47, national maximal allowed concentration value is 2 mg m-3). The control group (C group) consisted of 75 subjects employed in lime production who had not been occupationally exposed to aluminium or any known toxic substance.Erythrocyte aluminium concentrations were significantly higher in the exposed group than controls [Al group (8.41+/-3.66) microg L-1, C group (5.60+/-0.86) microg L-1, p<0.001]. In the Al group, erythrocyte malondialdehyde concentration was also significantly higher [Al group (189.59+/-81.27) micromol L-1, C group (105.21+/-49.62) micromol L-1, p<0.001] and antioxidative enzyme activity reduced for glucoso-6-phosphate-dehydrogenase [Al group (5.05+/-1.70) IU g-1 Hb, C group (12.53+/-4.12) IU g-1 Hb, p<0.001], glutathione reductase [Al group (1.41+/-0.56) IU g-1 Hb, C group (1.89+/-0.57) IU g-1 Hb, p<0.001], glutathione peroxidase [Al group (12.37+/-5.76) IU g-1 Hb, C group (15.54+/-4.85) IU g-1 Hb, p<0.001], catalase [Al group (116.76+/-26.60) IU g-1 Hb, C group (158.81+/-71.85) IU g-1 Hb, p<0.001] and superoxide dismutase [Al group (1175.8+/-149.9) IU mg-1 Hb, C group (1377.9+/-207.5) IU mg-1 Hb, p<0.001].     

沥青烟作业工人脂质过氧化水平的观察

目的 探讨沥青烟作业工人脂质过氧化水平和红细胞膜ATP酶活力的改变.方法 选择炭素分厂生阳极车间接触沥青烟工人53名为观察组,选择该厂非沥青烟作业职工50名为对照组,检测血浆中脂质过氧化水平相关指标谷胱甘肽过氧化物酶(GSH-Px)、一氧化氮合酶(NOS)、总超氧化物歧化酶(T-SOD)活力和丙二醛(MDA)、一氧化氮(NO)含量及总抗氧化能力(T-AOC)、抑制羟自由基能力和红细胞膜Na~+-K~+-ATPase和Ca~(2+)-ATPase活力.结果 观察组抑制羟自由基能力为(786.03±227.54)U/ml,与对照组[(897.79±153.87)U/ml)]比较明显降低,差异有统计学意义(P<0.05).观察组MDA含量为(11.97±4.26)nmol/ml,明显高于对照组[(9.26±4.90)nmol/ml)],差异有统计学意义(P<0.05).观察组红细胞膜Na~+-K~+-ATPase活力为(18.83±9.97)U/ml,明显低于对照组[(27.06±11.62)U/ml)],差异有统计学意义(P<0.05).抑制羟自由基能力、GSH-Px活力与工龄呈负相关(r=-0.320,r=-0.347,P<0.05),MDA含量与工龄呈正相关(r=0.421,P<0.01).红细胞膜Na~+-K~+-ATPase和Ca~(2+)-ATPase活力与工龄均无明显相关性.结论 沥青烟可引起作业工人脂质过氧化水平和红细胞膜ATP酶活力的改变     

Relationships between blood lead concentration and aminolevulinic acid dehydratase in alcoholics and workers industrially exposed to lead

Blood lead concentration (Pb-B), aminolevulinic acid dehydratase (ALAD), and gamma-GT were measured in 265 workers industrially exposed to lead and in 184 patients with liver disease resulting from alcohol consumption. The first group was divided according to alcohol use, i.e., nondrinkers, moderate drinkers, and heavy drinkers. The second group was divided according to the following criteria: hepatopatic without cirrhosis, hepatopatic with compensated cirrhosis, and hepatopatic with decompensated cirrhosis. Heavy drinkers who were industrially exposed had the highest Pb-B (40.4 +/- 14.6 micrograms/dl) and the lowest ALAD (22.2 +/- 9.1 U/L). The correlations between Pb-B and ALAD show no significant change with the increase of Pb-B. In the alcoholic group, 76 patients with alcoholic liver disease without cirrhosis had the highest Pb-B (40.3-9.1 micrograms/dl) and ALAD the lowest (18.6 +/- 7.7 U/L). The negative correlation between Pb-B and log ALAD disappeared completely in individuals with Pb-B that exceeded 50 micrograms/dl, independent from the seriousness of illness.     

Lipid abnormalities in workers exposed to dioxin

Ten years after an incident in which workers were exposed to tetrachlorodibenzodioxin (TCDD) a controlled biochemical study showed statistically significant increases in the serum cholesterol and triglyceride concentrations of workers both with and without chloracne. Urinary excretion of D-glucaric acid was significantly higher for all workers.     

Lipid abnormalities in workers exposed to dioxin.

Ten years after an incident in which workers were exposed to tetrachlorodibenzodioxin (TCDD) a controlled biochemical study showed statistically significant increases in the serum cholesterol and triglyceride concentrations of workers both with and without chloracne. Urinary excretion of D-glucaric acid was significantly higher for all workers.     

低浓度铅接触女工血铅与红细胞游离原卟啉的关系

为研究低浓度铅作业对女工是否有影响,调查了铅接触浓度（时间加权平均浓度）为０．０３１５ｍｇ／ｍ＾３的女工８２名,分别测定血游离原卟啉（ＦＥＰ）、血铅、尿铅。结果表明ＦＥＰ、血铅、尿铅与对照组比较差异有显著性（Ｐ＜０．０１）。指标间相关性较好呈剂量－反应关系。血铅和ＦＥＰ阳性检出率分别为２０．７３％和２１．９５％,２项均超过正常上限的检出率（１３．４％）。智商ＩＱ值为６０￣７９、８０￣８９、９０￣１     

Erythrocyte deformability in workers exposed to lead.

Erythrocyte deformability and other hematological indicators were determined in 17 male workers exposed to lead at a secondary lead refinery and 13 controls. Blood lead, urine lead, urine coproporphyrin, delta-aminolevulinic acid and erythrocyte zinc protoporphyrin were determined to evaluate the degree of lead exposure in the lead workers above. For the measurement of erythrocyte deformability, the microfilter method was used. The results were summarized as follows: 1. The mean values of blood lead, urine lead, urine coproporphyrin, urine delta-aminolevulinic acid and erythrocyte zinc protoporphyrin levels in lead workers were 53.5 micrograms/100g, 141.4 micrograms/l, 115.9 micrograms/l, 12.0 mg/l and 68.9 micrograms/dl respectively, suggesting a moderate influence of lead exposure. 2. The mean values of erythrocyte count, hematocrit and hemoglobin were significantly lower in lead workers than those in controls. No significant differences were found in the mean values of mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration and corpuscular natrium and potassium between lead workers and controls. 3. Erythrocyte deformability was significantly reduced in lead workers compared with controls.     

Genotoxicity evaluation in workers occupationally exposed to lead

Lead (Pb) is a widely used heavy metal with a broad industrial usage. Nevertheless, Pb is a serious public health issue as it is one of the most widespread environmental and industrial toxins. The aim of this investigation was to assess the genotoxicity of Pb using the comet assay, micronucleus (MN) and chromosomal aberrations (CA) test. Blood and urinary Pb content, levels of δ-aminolevulinic acid dehydratase in the erythrocytes (E-ALAD) and δ-aminolevulinic acid in urine (U-ALA) were determined. The exposure associated oxidative stress was also studied. The study group comprised of 90 male Pb recovery unit workers and 90 matched controls. The results indicated that the exposed workers had a significantly higher mean comet tail length than that of controls (P<0.05). Analysis of micronuclei in buccal epithelial cells (BEC’s) and peripheral blood lymphocytes (PBL) revealed that there was a significant increase in frequency of MN in exposed subjects than controls. The frequency of aberrant metaphases was also found to be significantly elevated in the Pb exposed workers. The levels of antioxidant enzymes were relatively reduced (P>0.05) while the rate of lipid peroxidation was higher in the exposed subjects. Blood and urinary Pb concentrations were found to be higher in exposed workers than in controls. E-ALAD levels were reduced and U-ALA levels were elevated in the exposed subjects in comparison to controls. Results of analysis, taking the confounding factors into consideration provide evidence for the association of Pb exposure and genotoxicity, and predict the increased risk of cancer to the exposed workers. In view of the observed results, it can be strongly concluded that the workers comprise the risk group and adequate safety, precautionary and preventive measures could only minimize exposure and the related health hazards.     

Adverse effects in workers exposed to inorganic lead

This paper describes a retrospective cohort study comparing 60 workers occupationally exposed to inorganic lead and 60 matched controls. All subjects were assessed using data obtained from a specially designed Questionnaire for lead exposure and toxic effects assessment, physical examination, spirometry, ECG, and laboratory tests including blood lead level (BLL) and biomarkers of lead toxic effects. Muscle pain, droopiness, and work-related nasal symptoms were significantly more frequent in lead workers. The prevalence of lung symptoms was higher in lead workers than in controls, but not significantly (20 % vs. 6.6 %, respectively). Mean values of BLL and delta-aminolevulinic acid (ALA) were significantly higher in lead workers. The activity of delta-aminolevulinic acid dehydratase (ALAD) in lead workers was significantly lower than in controls. Abnormal of BLL, ALAD, and ALA were more frequent in lead workers, with statistical difference for BLL and ALAD. Inverse correlation was found between BLL and ALAD, and positive correlation between BLL and age, years of employment, and years of exposure. Inverse correlation was found between ALAD and age, years of employment, years of exposure, blood pressure, alcohol consumption, and years of alcohol consumption. Changes in spirometry correlated inversely with BLL. A positive correlation was found between BLL and erythrocyte count and haemoglobin concentration, whereas it was inverse for ALAD and haemoglobin concentration. A significant difference was found for BLL and ALAD, with a very high odds ratio (14.64 and 7.23, respectively) and high relative risk (4.18 and 3.08, respectively). Our data have confirmed the association between occupational lead exposure and deviation in specific biological markers of lead effect and between the role of occupational exposure in the development of adverse effects.     

Neurophysiological studies on workers exposed to lead

Nerve conduction and somatosensory evoked potential studies were undertaken on 46 workers exposed to a combination of organic and inorganic lead. In addition electroencephalograms were carried out on 20 of the workers; the results were compared with those obtained for workers not exposed to lead. The workers exposed to lead had a mean blood lead concentration of 2.35 mumol/l (48.7 micrograms/100 ml), whereas the concentration for workers not exposed to lead was 0.76 mumol/l (15.8 micrograms/100 ml). The mean maximum motor conduction velocities of the median and the posterior tibial nerves were significantly lower in the workers exposed to lead than in the controls. Similarly, the distal latency for these two nerves was significantly prolonged for the workers exposed to lead. No significant differences for the two groups of workers were seen in the nerve conduction and distal latency measurements of the median (sensory) and the sural nerves. The EEG studies of the 20 workers exposed to lead showed no abnormalities. The somatosensory evoked potential of the median (sensory) and posterior tibial nerves were significantly prolonged when measured at the negative and positive deflections. The results suggest that, in addition to nerve conduction velocities, somatosensory evoked potential and distal latency are suitable measurements to detect subclinical neurological damage among workers exposed to lead. As these changes were seen at blood lead concentrations of 2.35 mumol/l (48.7 micrograms/100 ml) there may be a need for more stringent monitoring of workers exposed to lead.     

Relation between urinary beta-aminoisobutyric acid excretion and concentration of lead in the blood of workers occupationally exposed to lead.

Urinary beta-aminoisobutyric acid (ABA) concentration was determined by fluorometric high performance liquid chromatography in 22 workers occupationally exposed to lead. The urinary excretion of ABA was increased with increasing exposure to lead. The excretion of urinary ABA had a significant correlation with concentration of lead in blood (Pb-B) (r = 0.581), similar to the correlation of Pb-B with urinary delta-aminolaevulinic acid (ALA) concentration (r = 0.563). The determination of urinary ABA concentration in workers exposed to lead, therefore, may offer a new approach for evaluating the health effect of lead.     

Relation between urinary beta-aminoisobutyric acid excretion and concentration of lead in the blood of workers occupationally exposed to lead.

Urinary beta-aminoisobutyric acid (ABA) concentration was determined by fluorometric high performance liquid chromatography in 22 workers occupationally exposed to lead. The urinary excretion of ABA was increased with increasing exposure to lead. The excretion of urinary ABA had a significant correlation with concentration of lead in blood (Pb-B) (r = 0.581), similar to the correlation of Pb-B with urinary delta-aminolaevulinic acid (ALA) concentration (r = 0.563). The determination of urinary ABA concentration in workers exposed to lead, therefore, may offer a new approach for evaluating the health effect of lead.