Influence of free radicals on cardiovascular risk due to occupational exposure to mercury.
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This study was designed to investigate the relation between occupational exposure to mercury and cardiovascular risk, as well as free radicals. The study subjects included 30 male workers exposed to mercury from a fluorescent lamp plant in Alexandria after exclusion of 12 workers with conditions that may bias the results. A matched control group of 20 male subjects were selected from a food industrial plant. The participants were subjected to interview, clinical examination, electrocardiography and R-R deep breathing variability test as a measure of cardiac autonomic function. Spot urine and venous blood samples were collected to measure mercury levels. Free radicals related markers were measured in serum namely lipid peroxide, superoxide dismutase (SOD) activity, catalase activity and glutathione S-transferase. Results showed significant longer electrocardiographic Q-Tc interval, which is corrected to heart rate, in exposed workers than in controls (p=0.002). The R-R deep breathing variability indices were significantly increased among exposed workers in comparison to controls (maximal variation (MV) ratio, p=0.024 & MV rate, p=0.019). The mercury levels in both urine and blood of exposed workers were significantly higher than controls (p<0.0001), with mean levels exceeding the permissible limits. Free radicals related markers revealed significant higher level of lipid peroxide, as well as significant lower levels of SOD activity, catalase activity and glutathione S-transferase among exposed workers than among controls (p<0.0001 for all). Independent relations were observed between Q-Tc and lipid peroxide, and between MV rate and SOD and catalase activities among exposed workers after adjustment for the confounders by multivariate regression analyses. These findings may suspect a cardiac autonomic dysfunction probably related to free radicals in mercury exposed workers. Also, it may through light on some preventive implications.Keywords:
Lipid peroxide
Venous blood
Mercury
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Exposure to single chemicals and associated disorders in occupational environments has received significant attention. Understanding these events holds great promise for risk identification, assessment and chemical induced disease prevention. Fifty (50) fasting male workers, age range 18-50 years exposed to chemical mixtures in a works department, mean duration 17.7±10.1 years and 30 controls matched for age, diet, sex and other demographic characteristics except exposure to chemicals were selected. Body mass index (BMI), antioxidant status and other biochemical indices including plasma proteins (total protein) and subsets, albumin and total globulins were determined in plasma. The BMI was similar between chemical workers (exposed) and controls (p>0.05). Uric acid level was significantly higher in the exposed than in the controls (p 0.05). Plasma proteins were significantly lower in chemical workers than in controls (p<0.001). Total globulins was significantly reduced in chemical workers (p<0.01). Other variables did not differ significantly. These data are consistent with the existence of oxidative stress in these chemical workers.
Key words: Chemical mixtures, occupational exposure, oxidative stress.
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To study the effects of exposure to low concentration of mixed benzene on their semen quality and very early fetal loss (VEFL) in the occupational population.Environmental monitoring and biological monitoring were conducted in 126 employees exposed to mixed benzene and 60 unexposed ones selected from a large petrochemical corporation and a large chemical fiber corporation. Quality of semen in 70 male workers in the exposed group and 90 male internal controls and 132 male external controls were analyzed, and urinary beta-human chorionic gonadotropin (beta-hCG) was determined for 42 female exposed workers and 49 female internal controls and 118 external controls.1. Exposure to mixed benzene mainly existed in low concentrations (0.7-27.0 mg/m3) in the petrochemical corporation, and urine concentration of t, t-MA in the workers correlated significantly to benzene concentration in ambient air of the workshops (r = 0.64, P = 0.03). 2. The sperm progression and motility in the exposed (1.97 +/- 0.63 and 0.55 +/- 0.16) and the internal control (1.97 +/- 0.69 and 0.55 +/- 0.17) groups were significantly (P < 0.05) lower than those in the external control group (2.56 +/- 0.61 and 0.60 +/- 0.13), however, the sperm abnormality rates in the exposed and internal control groups were significantly (P < 0.01) higher than those in the external control group, and the summary abnormality rate of sperm in the exposed group (85.71%) was higher than that in the internal (70.00%) and external control (76.51%) groups (P < 0.05). 3. The incidence rates of the VEFL in female workers and the cyclic occurrence of VEFL both in the exposed and internal control groups (10.42% and 9.60%) were higher than those in the external control group (5.09%), with statistical significance (P < 0.05).Exposure to low concentration of mixed benzene maybe correlated with the declined quality of semen and VEFL in occupational workers, and urinary t, t-MA and beta-hCG can be used as biomarkers of exposure and effect, respectively.
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Objective To understand the effect of manganese exposure on liver and cardiovascular functions.Methods Serum TPR,ALB,ALT,AST,TTT,ChE,heartbeat,ECG and blood pressure of 15 exposed workers and 15 control subjects were examined in the present investigation.Data collected were analyzed by SPSS software in microcomputer for paired design.Results The geometric mean of air MnO\-2 level was 0 25(0.09-1.04)mg/m\+3.The heartbeat of the female of exposed workers was significantly slower than that of the female of control workers.The mean of systolic blood pressure of the male of exposed workers was significantly higher than that of the male of control workers.There were no significant differences in the other indices of cardiovascular and liver functions between the exposed and the control groups.Conclusion The present findings suggested that the workers' cardiovascular function could be affected by low level manganese exposure.
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Lead (geology)
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Objectives:To study any possible correlation between blood lead levels and some oxidative stress parameters of selected groups of lead-exposed automobile occupational Jordanian workers.Material and Methods: Blood lead levels were determined for a total of 90 male automobile workers aged within the range of 25-45 years old along with the group of 20 agematched healthy males control.To get an idea about the antioxidant status of controls and lead-exposed workers, and to estimate the oxidative stress caused by exposure to lead, we measured the hydrogen peroxide (H 2 O 2 ) concentration, superoxide dismutase (SOD) activity, lipid peroxidation as malondialdehyde (MDA) and total antioxidant capacity of controls and workers.Results: The study showed that lead levels in the case of workers were approximately 4-5 times as high as in controls 14.5-21 μg×dl -1 vs. 4.3 μg×dl -1 , respectively.There was a significant decrease (16-25%) in the level of plasma reduced glutathione and 21-33% decrease in total antioxidant capacity (TAOC) in all worker groups, as compared to controls.The results showed that the concentration of malondialdehyde (MDA) in plasma was higher (120-333%) in the case of workers than controls being the highest in automobile electronics and the lowest -in mechanics.Furthermore, there was 149-221% increase in hydrogen peroxide (H 2 O 2 ) concentration, and 26-38% increase in SOD activity in the case of workers compared to the control group.Conclusions: There is a strong evidence for the associations between occupational lead exposure and various markers of oxidative stress in Jordanian automobile occupational workers.Thus, there is an urgent need to raise awareness and to initiate suitable protection guidelines for workers.
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Objective To investigate the effects of occupational trichloroethylene(TCE)exposure on the levels of 3 urinary micro-proteins.Methods 112 TCE exposed workers and 70 controls were recruited.Occupational history,age,gender,smoking and alcoholic habits of all subjects were collected by questionnaire.Trichloro-acetic acid(TCA)level and the levels of urinary α1-microglobulin(α1-M),β2-microglobulin(β2-M),and retinal binding protein(RBP)were measured.Results The distributions of age,gender,smoking and alcoholic habits were not significantly different between TCE exposed workers and controls.The differences in levels of urinary α1-microglobulin(α1-M),β2-microglobulin(β2-M),and RBP in both exposed and control groups were not statistically significant.When the subjects were grouped according to working age,exposure concentration and levels of urinary TCA,the level of α1-M in workers with working age≥1.9a was significantly higher than that of the controls;the difference was significant(P0.05).In high TCE exposure concentration(198.0~257.0 mg/m3)and urinary TCA≥50 mg/L group,the RBP levels were significantly higher than those of the controls,the difference was significant(P0.05).Conclusions Long-term and high level TCE exposure could induce the increase of urinary α1-M and RBP levels among occupational exposed workers.
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Abstract Background Fish is considered protective for coronary heart disease (CHD), but mercury (Hg) intake from fish may counterbalance beneficial effects. Although neurotoxic effects of methylmercury (MeHg) are well established, cardiovascular effects are still debated. The objective of the present study was to evaluate blood pressure in relation to Hg exposure and fish consumption among a non-indigenous fish-eating population in the Brazilian Amazon. Methods The study was conducted among 251 persons from six communities along the Tapajós River, a major tributary of the Amazon. Data was obtained for socio-demographic information, fish consumption, height and weight to determine body mass index (BMI), systolic and diastolic blood pressure, and Hg concentration in hair samples. Results Results showed that overall, systolic and diastolic blood pressure, were relatively low (mean: 113.9 mmHg ± 14.6 and 73.7 mmHg ± 11.0). Blood pressure was significantly associated with hair total Hg (H-Hg), age, BMI and gender. No association was observed between fish consumption and blood pressure, although there were significant inter-community differences. Logistic regression analyses showed that the Odds Ratio (OR) for elevated systolic blood pressure (≥ 130 mmHg) with H-Hg ≥ 10 μg/g was 2.91 [1.26–7.28], taking into account age, BMI, smoking, gender and community. Conclusion The findings of this preliminary study add further support for Hg cardiovascular toxicity.
Methylmercury
Fish consumption
Mercury
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