The Relationship of Methylated Arginines with Urine Cadmium Levels.

BACKGROUND: In this study, we aimed to show that methylated arginines are the predictors of non-clinical atherosclerotic cardiovascular complications in metal workers exposed to Cd. METHODS: The 80 Cd-exposed metal workers and 80 non-exposed workers (control) included in the study were available for measuring arginine, ADMA, SDMA, and L-NMMA levels. RESULTS: The average urine Cd levels (CdU) found were 1.03 ± 0.8 µg/g creatinine (0.84 ± 0.65 µg/L) ranging from 0.01 to 3.00 µg/g creatinine in the control group and 5.41 ± 5.2 µg/g creatinine (4.29 ± 3.81 µg/L) ranged from 0.11 to 27.2 µg/g creatinine in metal workers. On the other hand, the median ratios of the different groups (exposed and control) were found to be 449.35 and 483.88 for arginine/ADMA and 1.28 and 1.33 SDMA/ADMA, respectively. CONCLUSIONS: The present study was undertaken to investigate the relationship between cadmium exposure and methylated arginines such as ADMA/SDMA/L-NMMA parameters which is important for the early detection atherosclerotic cardiovascular diseases.

Oxidative Stress Parameters, Selenium Levels, DNA Damage, and Phthalate Levels in Plastic Workers.

Di(2-ethylhexyl)phthalate (DEHP) is the most widely used phthalate. DEHP is highly used in PVC floorings and PVC windows and carpeting. The objective of this study was to determine sex hormone levels, oxidative stress parameters, selenium levels, DNA damage, and phthalate levels in plastics workers (n = 24, age = 20-58 years) working in the production of rubber mechanical goods and exposed to DEHP in workplace. The control group (n = 29, age = 25-54, all male) was selected from age-matched healthy adults. Antioxidant parameters and DNA damage were determined by spectrophotometry. Selenium levels were determined by atomic absorption spectroscopy. Plasma hormone levels were measured by chemiluminescence microparticle immunoassay. Plasma phthalate levels were determined by high-pressure liquid chromatography. Plastic workers had lower serum testosterone and free T4 levels and higher follicle-stimulating hormone levels vs. controls. Liver enzyme activities were markedly higher in workers vs. controls. There were also increases in plasma glutathione peroxidase levels and marked decreases in plasma selenium and erythrocyte total glutathione levels in plastics workers (P < 0.05 vs. control). Plasma 8-hydroxy-2'-deoxyguanosine levels were 14-fold higher in plastics workers than in controls. Plasma DEHP and mono(2-ethylhexyl)phthalate were also markedly higher in workers vs. controls. The results of this study show that occupational exposure to DEHP may lead to disturbances in sex hormones, increased liver problems, higher oxidative stress and DNA damage levels, and lower trace element concentrations in workers. More comprehensive and mechanistic studies with higher numbers of subjects are needed to show the unwanted effects of occupational exposure to DEHP.

Assessment of DNA damage in welders using comet and micronucleus assays.

Welding technology is widely used in pressurized containers, thermal power plants, refineries, chemical facilities and steel structures. Welders are exposed to a number of hazardous compounds such as ultraviolet (UV) radiation, electromagnetic fields, toxic metals and polycyclic aromatic hydrocarbons (PAHs). In the present study, 48 welders and an equal number of control subjects were evaluated for DNA damage in the whole blood and isolated lymphocytes using the comet assay. The genotoxic damage in buccal epithelial cells of subjects was determined by micronucleus (MN) assay. Metal(loids) such as Cr, Mn, Ni, Cu, As, Cd and Pb levels in blood samples were evaluated by using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Results of this study showed that DNA damage in blood, isolated lymphocytes, and buccal epithelial cells were significantly higher in workers compared to the controls. Also, these workers had remarkably higher blood Cr, Cu, Cd, Ni and Pb levels. These results showed that occupational exposure to welding fumes may cause genotoxic damage that can lead to important health problems in the workers. More extensive epidemiological studies should be performed that enable the assessment of health risk in welding industry.

Evaluation of Erectile Dysfunction and Left Ventricular Diastolic Parameters in Lead Exposed Workers.

BACKGROUND: Lead exposure causes a wide range of vascular diseases through oxidative stress, sympathetic hyperactivity and impairment in nitric oxide bioavailability. In this study, the association between the effects of lead exposure on left ventricular diastolic indices and erectile function were assessed. METHODS: A total of 94 lead-exposed workers without known cardiovascular diseases or risk factors and 30 healthy subjects were enrolled. Systolic and diastolic functions were measured using transthoracic echocardiography. All participants were non-smokers. The International Index of Erectile Function Questionnaire (IIEF-5) was used to diagnose and grade erectile dysfunction (ED). Echocardiographic parameters, IIEF-5 score and blood lead level (BLL) were analyzed. RESULTS: The mean age and median BLL were 32.3 ± 6.4 years and 19 µg/dL in the workers, respectively. Sixty-five (69.1%) workers and 9 control subjects (30%) had ED. The IIEF-5 score was lower in the workers (17.0 ± 6.1) than in the controls (22.7 ± 2.1). In the workers, E and e' waves and E/A ratio were lower, and A wave, E/e' ratio, and left atrial volume index (LAVI) were higher than in the controls. Additionally, BLL was correlated with IIEF-5 score, e' wave, and E/e' ratio. IIEF-5 score was correlated with e' wave, E/e' ratio and LAVI. BLL was an independent risk factor for a decreased e' wave and IIEF-5 score and increased E/e' ratio in the lead-exposed workers. CONCLUSIONS: Impairment of diastolic and erectile functions, despite a younger age and in the absence of accompanying risk factors, was correlated with increased BLL.

Serum S100B, NSE, and GRIA1 levels as neurological biomarkers in lead exposure

Background/aim: The central nervous system is one of the major targets in lead exposure. Biomarkers for the diagnosis and follow-up of lead exposure have not been identified. In this study, serum S100B, neuron-specific enolase (NSE), and glutamate receptor 1 (GRIA1) levels were determined as possible biomarkers for lead neurotoxicity. Material and methods: Twenty-five subjects with chronic lead exposure and 25 controls were included in the study. NSE and S100B were measured by electrochemiluminescence immunoassay with a Cobas E601 analyzer. GRIA1 levels were measured with an ELISA kit using a quantitative sandwich enzyme immunoassay technique. Results: GRIA1 levels were significantly higher in the lead exposure group than in the control group. No significant differences for NSE, S100B, ALT, AST, or creatinine in sera were found between lead exposure and control groups. Conclusion: Subjects with chronic lead exposure are found to have increased glutamate receptor levels and do not seem to have glial or neuronal damage, which can be demonstrated with the elevation of NSE and S100B levels. GRIA1 levels might be used as a biomarker for the neurotoxicity of lead.

Assessment of DNA damage in ceramic workers.

It is known that ceramic workers are potentially exposed to complex mixture of chemicals such as silica, inorganic lead, lime, beryllium and aluminum that can be associated with an increased risk of several diseases. All operations in the ceramic industries such as mixing, moulding, casting, shaking out and finishing jobs, have been associated with the higher exposure levels and in most of the silica-related industries, average overall exposure exceeded permissible exposure levels for respirable crystalline silica. The aim of this study was to evaluate the possible genotoxic damage in ceramic workers exposed to complex mixture of chemicals mainly crystalline silica. For this purpose, the blood and buccal epithelial cell samples were taken from the ceramic workers (n = 99) and their controls (n = 81). The genotoxicity was assessed by the alkaline comet assay in isolated lymphocytes and whole blood. Micronucleus (MN), binucleated (BN), pyknotic (PYC), condensed chromatin (CC), karyolytic (KYL), karyorrhectic (KHC) and nuclear bud (NBUD) frequencies in buccal epithelial cells and plasma 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) levels were also evaluated. In the study, 38 workers were diagnosed with silicosis, 9 workers were suspected to have silicosis, whereas 52 workers were found to be healthy. DNA damage in blood and lymphocytes; MN, CC + KHC, PYC frequencies in buccal epithelial cells and 8-oxodG levels in plasma were increased in workers compared to their controls. These results showed that occupational chemical mixture exposure in ceramic industry may cause genotoxic damage that can lead to important health problems in the workers.

Alteration of thiol-disulfide homeostasis in workers occupationally exposed to arsenic.

This study evaluates the redox state in occupationally arsenic-exposed workers (n = 71) by assessing the dynamic serum thiol-disulfide homeostasis. We determined the serum thiol-disulfide homeostasis parameters of exposed workers and controls (n = 43) using a novel automated colorimetric assay. Median urinary As and 8-isoprostane levels of exposed group were significantly higher than control group (16.40 µg/L vs 2µg/L, p < .001 and 2.28 ng/ml vs 0.54 ng/ml, p < .001, respectively). Disulfide level, disulfide/native thiol ratio, and disulfide/total thiol ratio were significantly higher in exposed group. The mean ceruloplasmine and myeloperoxidase activities of As-exposed group were significantly higher than control group (117.15 U/L vs 87.02 U/L, p = .035 and 148.53 U/L vs 97.75 U/L, p = .000, respectively). The median catalase activity did not differ in the two groups. Our findings revealed that As disrupts the thiol-disulfide homeostasis in favor of disulfide.

Possible changes of New-Generation inflammation markers with occupational lead exposure.

OBJECTIVES: Occupational lead (Pb) exposure is still an important health problem in the world. Long-term Pb exposure causes several adverse effects. The aim of this study was to investigate the changes of inflammation markers with chronic Pb exposure by analyzing neopterin levels and kynurenine (Kyn) to tryptophan (Trp) ratio that reflects indolamine 2,3-dioxygenase activity and to compare with healthy volunteers' parameters. METHODS: Blood lead levels (BLLs) were analyzed by atomic absorption spectrometry. Urinary neopterin and serum Kyn and Trp levels were analyzed by high-performance liquid chromatography. RESULTS: According to our results, mean BLL of the 29 workers was 20.4±9.6 µg/dl. Urinary neopterin levels, serum Kyn levels, and Kyn/Trp of Pb workers (188±52 µmol/mol creatinine, 2.70±0.66 µM, and 43.19±10.38 µmol/mmol, respectively) were significantly higher than controls (144±35 µmol/mol creatinine, 2.08±0.34 µM, and 32.24±7.69 µmol/mmol, respectively). Pb-exposed workers were divided into further three groups according to their BLLs: as 10-19 µg/dl (n=18), 20-29 µg/dl (n=8), and 30-49 µg/dl (n=3). Neopterin levels of the workers with BLL of 30-49 µg/dl were significantly higher than those of BLL with 10-29 µg/dl, while Trp levels decreased. Kyn/Trp of workers with BLL of 30-49 µg/dl were elevated significantly compared with the workers with BLL<30 µg/dl. In addition to neopterin, Kyn and Kyn/Trp levels were positively influenced by Pb exposure. CONCLUSIONS: Increased level of inflammation markers confirms the adverse effects of Pb even low BLLs, and we suggest that monitoring BLLs with inflammation markers could help to prevent serious occupational health problems.

Effects of Occupational Silica Exposure on OXIDATIVE Stress and Immune System Parameters in Ceramic Workers in TURKEY.

Silica is the second most common element after oxygen, and therefore, exposures to crystalline silica dust occur in a large variety of occupations such as metal foundries, constructions, and ceramic, quarry, and pottery industries. Since crystalline silica exposure has been linked with silicosis, lung cancer, and other pulmonary diseases, adverse effect attributed to this element has be a cause for concern worldwide. Silica dust exposure in workers is still considered to be important health problem especially in developing countries. The aim of the study was to investigate the effects of occupational silica exposure on oxidative stress parameters including the activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), and levels of total glutathione (GSH) and thiobarbituric acid reactive substance (TBARS) as well as immune system parameters such as interleukin (IL)-1α, IL-1ß, IL-2, IL-4, IL-6, and IL-10 and tumor necrosis factor (TNF)-α in Turkish ceramic workers. In this study, nearly 50% of Turkish ceramic workers were diagnosed with silicosis. Eighty-four percent of these silicotic workers were found to present with profusion category 1 silicosis, whereas controls (n = 81) all displayed normal chest radiographs. Data demonstrated a significant decrease in levels of GSH and activities of CAT, SOD, and GPx, but a significant increase in MDA levels and activity of GR in all workers. Further, workers possessed significantly higher levels of IL-1α, IL-1ß, IL-2, IL-4, IL-6, IL-10, and TNF-α. These observations suggest that ceramic workers may have impaired antioxidant/oxidant status and activated immune system indicative of inflammatory responses.

Evaluation of the ambulatory arterial stiffness index in lead-exposed workers.

OBJECTIVE: Lead exposure has been associated with various cardiovascular disorders. It may also cause increased inflammation and fibrosis in the arterial system resulting in an increase in arterial stiffness. In this study, the ambulatory arterial stiffness index (AASI), which is a technique that measures arterial stiffness, was evaluated in occupationally lead-exposed workers. METHODS: In this cross-sectional study, 68 lead-exposed workers without known cardiovascular risk factors and 68 healthy subjects were evaluated according to the 24-hour ambulatory blood pressure monitorization (ABPM) profiles and blood and 24-hour urine lead levels. A regression slope of diastolic over systolic blood pressure (BP) was computed in each participant. AASI was defined as 1 minus the regression slope. RESULTS: There were no significant differences in terms of baseline demographic, clinical, echocardiographic characteristics, and ABPM profiles between the groups. In lead-exposed workers, the mean age was 34.7±8.1 years, and the median blood and urine lead levels were 40.5 µg/dL and 34.9 µg/L, respectively. AASI was 0.42±0.10 in lead-exposed workers and 0.37±0.10 in control subjects (p=0.007). In correlation analysis, AASI was correlated with both blood (r=0.417, p<0.001) and urine lead (r=0.242, p=0.047) levels. In regression analysis, blood lead level was found to be associated with AASI (ß=0.086, p<0.001). CONCLUSION: AASI, which is an indicator of arterial stiffness, was found to be higher in lead-exposed workers than in healthy individuals. Increased AASI may be considered an early sign of arterial involvement in case of lead exposure.

Assessment of heart rate response to exercise and recovery during treadmill testing in arsenic-exposed workers.

BACKGROUND: Arsenic exposure is associated with various cardiovascular diseases. The aim of the present study was to assess cardiac autonomic function via heart rate response to exercise and recovery period of treadmill testing in arsenic-exposed workers. METHODS: Sixty-five (65) occupationally arsenic-exposed workers and 35 healthy controls were enrolled. Blood and urinary arsenic levels were analyzed and symptom limited maximal treadmill exercise test were performed. Chronotropic response to exercise including age-predicted maximal heart rate (APMHR), heart rate reserve (HRreserve ), age-predicted HRreserve (APHRreserve ) and adjusted HRreserve and 1st-, 2nd-and 3rd-min heart rate recovery (HRR) indices were calculated. RESULTS: Baseline clinical and echocardiographic parameters, exercise test duration, resting and maximal heart rate, peak exercise capacity, HRreserve , APMHR, APHRreserve , and adjusted HRreserve were found to be similar between groups. HRR1 (22.0 ± 4.3 vs. 24.3 ± 3.1 bpm, p = .003) and HRR2 (43.2 ± 6.2 vs. 46.7 ± 6.4 bpm, p = .012) were significantly lower in arsenic-exposed workers compared to controls. Blood and urinary arsenic levels negatively correlated with HRR1 (r = -.477, p < .001 and r = -.438, p < .001, respectively) and HRR2 (r = -.507, p < .001 and r = -.412, p < .001 respectively). CONCLUSIONS: Arsenic-exposed workers had lower HRR indices than normal subjects but chronotropic response were similar. Cardiac autonomic dysregulation may be one of the cardiovascular consequences of arsenic exposure.

Comprehensive Electrocardiographic Analysis of Lead Exposed Workers: An Arrhythmic Risk Assessment Study.

BACKGROUND: To evaluate electrocardiographic parameters which are related with atrial and ventricular arrhythmias measured from 12-lead surface electrocardiogram (ECG) in workers occupationally exposed to lead. METHODS: Sixty lead-exposed workers and 60 healthy controls were enrolled. Twelve-lead surface ECG was recorded and measurements of P wave durations (Pmax, Pmin) and P wave dispersion (PWD), QT durations and dispersion (QTd), corrected QT (QTc), Tp-e interval, and Tp-e/QT ratio were analyzed. RESULTS: The lead-exposed and control groups were similar with respect to baseline demographic, laboratory, and transthoracic echocardiographic indices. PWD (26.3 ± 9.7 vs 22.0 ± 9.0 ms, P = 0.014), Pmin (89.9 ± 13.8 vs 79.2 ± 10.1 ms, P < 0.001), and Pmax (116.2 ± 15.0 vs 101.2 ± 14.2 ms, P < 0.001), QT maximum (377.0 ± 27.6 vs 364.9 ± 28.5 ms, P = 0.02), QTd (38.4 ± 16.5 vs 30.5 ± 12.4 ms, P = 0.004), Tp-e interval (78.9 ± 16.5 vs 70.3 ± 14.5 ms, P = 0.003), and Tp-e/QT ratio (0.22 ± 0.04 vs 0.20 ± 0.04, P = 0.013) were significantly higher in lead-exposed workers. QT minimum and QTc values did not differ significantly. QT maximum, QTd, and Tp-e/QT ratio were correlated with urine lead level and Tp-e interval was correlated with both blood and urine lead levels. CONCLUSIONS: Lead-exposed workers have a higher risk for atrial and ventricular arrhythmias even without overt cardiac diseases compared with healthy subjects. These workers should be followed closely for adverse cardiovascular outcomes especially arrhythmias.

Dynamic disulfide/thiol homeostasis in lead exposure denoted by a novel method.

Lead is a toxic heavy metal, and prevention of human exposure to lead has not been accomplished yet. The toxicity of lead is continually being investigated, and the molecular mechanisms of its toxicity are still being revealed. In this study, we used a novel method to examine thiol (SH)/disulfide homeostasis in workers who were occupationally exposed to lead. A total of 80 such workers and 70 control subjects were evaluated, and their native and total SH values were measured in serum using a novel method; their blood lead levels were also assessed. The novel method used for SH measurements was based on the principle of measuring native SH, after which disulfide bonds were reduced and total SHs were measured. These measurements allowed us to calculate disulfide amounts, disulfide/total SH percent ratios, disulfide/native SH percent ratios, and native SH /total SH percent ratios. We found that disulfide levels were significantly higher in workers who were exposed to lead (21.08(11.1-53.6) vs. 17.9(1.7-25), p < 0.001). Additionally, the disulfide/native SH and disulfide/total SH percent ratios were higher in exposed workers, while the native SH/total SH percent ratios were higher in the control subjects. Furthermore, the lead and disulfide levels showed a positive correlation, with p < 0.001 and a correlation coefficient of 0.378. Finally, the novel method used in this study successfully showed a switch from SH to disulfide after lead exposure, and the method is fully automated, easy, cheap, reliable, and reproducible. Use of this method in future cases may provide valuable insights into the management of lead exposure.

Comparison of European Standard Patch Test Results of 330 Patients from an Occupational Diseases Hospital.

Background and Aim. Contact dermatitis (CD) is the most prevalent occupational skin disease with a significant impact on quality of life. Patch testing is used for the identification of responsible allergens which may improve protective and preventive measures in the workplace. Herein, we aim to identify the demographic characteristics and occupation of patients with early diagnosis of occupational CD and compare patch test results. Materials and Methods. The study included 330 patients referred to our clinic between April 2009 and April 2011 and who were patch-tested with 28-allergen European Standard Test. Results. 126 (38%) patients were female and 204 (62%) were male with a mean age of 36.12 (±13.13) years. Positive allergic reactions were observed in 182 (55%) patients. Nickel sulphate (41/126) and potassium dichromate (39/204) were significantly the most common allergens in women and men, respectively (P < 0.005). Additionally, the most common occupation in women was household activities (83/126) and in men was manufacturing (80/204). Conclusion. The allergens to which people become sensitized differ according to their working environment and occupation. Classification of occupations is important for identification of sensitization risks and monitoring of changes in allergen distribution of different occupations.

Exercise heart rate recovery assessment of the cardiac autonomic nervous system in workers occupationally exposed to lead.

OBJECTIVE: The aim of the present study was to assess cardiac autonomic function via indices of exercise heart rate recovery (HRR) in workers occupationally exposed to lead. METHODS: A total of 98 lead-exposed workers and 98 healthy controls were enrolled. All underwent exercise testing and transthoracic echocardiography. HRR indices were calculated by subtracting 1st- (HRR1), 2nd- (HRR2), and 3rd-minute (HRR3) heart rates from maximal heart rate (HR). Exercise test parameters- HRR in particular- were compared between groups, and correlation analysis of blood, 24-hour urine lead levels, and test parameters was performed. RESULTS: Baseline demographic and clinical characteristics were found to be similar between groups. Mean HRR1 (26.2±3.6 vs 29.0±4.1 bpm, p<0.001), HRR2 (42.6±3.9 vs 46.9±3.7 bpm, p<0.001), and HRR3 (56.6±4.5 vs 61.8±4.3 bpm, p<0.001) values were significantly lower in the lead-exposed group than in the healthy controls. HRR1 was found to be significantly correlated with blood (r:-0.415; p<0.001) and 24-hour urine lead levels (r:-0.446; p<0.001). HRR2 and HRR3 were significantly correlated with 24-hour urine lead level (r:-0.396; p<0.001 and r:-0.233; p=0.021, respectively). CONCLUSION: Lead-exposed workers had lower HRR indices than normal subjects. Blood and 24-hour urine lead levels were significantly associated with HRR indices. Cardiac autonomic functions may be affected by exposure to lead, and those occupationally exposed should be closely followed for adverse cardiovascular outcome.

Assessment of the Cardiac Autonomic Nervous System in Mercury-Exposed Individuals via Post-Exercise Heart Rate Recovery.

OBJECTIVE: The aim of this study was to assess exercise heart rate recovery (HRR) indices in mercury-exposed individuals when evaluating their cardiac autonomic function. SUBJECTS AND METHODS: Twenty-eight mercury-exposed individuals and 28 healthy controls were enrolled. All the subjects underwent exercise testing and transthoracic echocardiography. The HRR indices were calculated by subtracting the first- (HRR1), second- (HRR2) and third-minute (HRR3) heart rates from the maximal heart rate. The two groups were evaluated in terms of exercise test parameters, especially HRR, and a correlation analysis was performed between blood, 24-hour urine and hair mercury levels and the test parameters. RESULTS: The mercury-exposed and control groups were similar in age (37.2 ± 6.6 vs. 36.9 ± 9.0 years), had an identical gender distribution (16 females and 12 males) and similar left ventricular ejection fractions (65.5 ± 3.1 vs. 65.4 ± 3.1%). The mean HRR1 [25.6 ± 6.5 vs. 30.3 ± 8.2 beats per min (bpm); p = 0.009], HRR2 (43.5 ± 5.3 vs. 47.8 ± 5.5 bpm; p = 0.010) and HRR3 (56.8 ± 5.1 vs. 59.4 ± 6.3 bpm; p = 0.016) values were significantly lower in the mercury-exposed group than in the healthy controls. However, there were no significant correlations between blood, urine and hair mercury levels and exercise test parameters. CONCLUSIONS: Mercury-exposed individuals had lower HRR indices than normal subjects. In these individuals, mercury exposure measurements did not show correlations with the exercise test parameters, but age did show a negative correlation with these parameters. Therefore, cardiac autonomic functions might be involved in cases of mercury exposure.

Evaluation of bone mineral density and 25-hydroxyvitamin D levels in subjects with silica exposure.

OBJECTIVE: The purpose of the study was to evaluate the bone mineral density (BMD) and 25-hydroxyvitamin D (25(OH)D) levels in patients with silica exposure. MATERIALS AND METHODS: The study included 104 male subjects with silica exposure and 36 healthy subjects. Posterior-anterior radiographs were classified according to the International Labour Office (ILO) Classification. Category 0 patients were classified as Group I (n = 54), category I patients were classified as Group II (n = 25), Category II and III patients were classified as Group III (n = 25). RESULTS: Femoral neck BMD values were significantly lower in Group III (p = 0.007). Lumbar vertebrae BMD values were significantly lower in all groups with silica exposure than in the control group (p = 0.000). The osteoporosis rate was significantly higher in Group III (p = 0.000). Subjects with silica exposure were determined to have diminished 25(OH)D levels (p = 0.012). CONCLUSION: The results of this study demonstrated that subjects with silica exposure have diminished BMD and 25(OH)D levels.

Arsenic related hearing loss in miners.

PURPOSE: Arsenic is a toxic metalloid that carries number of potential risks to human health, although there is little evidence of the ototoxic effect of arsenic. The aim of this study was to identify the relationship between arsenic exposure and hearing loss by measuring blood arsenic concentrations and hearing among miners. MATERIALS AND METHODS: This research is a retrospective case control study. Included in the study were miners employed in a single silver mine whose blood arsenic concentrations were high. A comparison was made on the pure tone audiometry measurements taken from miners exposed only to arsenic (Group 1), those exposed to both arsenic and noise (Group 2) and a control group exposed to neither arsenic nor noise (Group 3). RESULTS: It was found that for both ears at all frequencies, the hearing level of Group 3 was better than the hearing levels of both Group 1 and Group 2. There was no correlation between the blood arsenic levels and hearing levels in both ears. CONCLUSION: This study has revealed the ototoxic effects of arsenic. As blood arsenic concentrations do not reflect long-term exposure, no correlation was identified between blood arsenic concentrations and hearing levels. Further studies will be needed to clarify the mechanisms involved in the effect of arsenic on hearing. This paper represents the largest study to date focusing on the isolated effects of arsenic on hearing through the use of a clinical auditory test.

The Effects of Lead Exposure on Serum Uric Acid and Hyperuricemia in Young Adult Workers: A Cross-sectional Controlled Study.

OBJECTIVES: This study aims to evaluate the relationship between serum uric acid levels and renal functions in asymptomatic subjects who had occupational lead exposure, particularly for shorter durations whereby saturnine gout has also been discussed. PATIENTS AND METHODS: In this retrospective study, files of 100 males (mean age 34.5±5.9 years; range, 21 to 47 years) with occupational risk for lead exposure and 100 healthy male controls (mean age 34.47±5.8 years; range 21 to 47 years) were reviewed. Demographic characteristics of the subjects and laboratory test results were recorded from the files. Creatinine clearance and 24-hour urinary creatinine were measured in the lead-exposed group. RESULTS: In the lead-exposed group, mean serum uric acid level was higher than those of the control group (p<0.001). Lead exposure time was negatively correlated with 24-hour urinary creatinine levels (r= -0.373, p<0.001). In addition, serum uric acid levels were positively correlated with serum creatinine levels (r=0.412, p<0.001) in the exposed group. Six patients had hyperuricemia (serum uric acid level >6.8 mg/dL) in the lead- exposed group; however, all subjects' serum uric acid level was lower than 6.8 mg/dL in the control group (p=0.029). Although 22 subjects had higher uric acid levels than 6.0 mg/dL in the lead-exposed group, only one control had higher uric acid level than 6.0 mg/dL (p<0.001). CONCLUSION: In light of our results, we may conclude that workers with lead exposure have higher frequency of hyperuricemia and higher serum uric acid levels than those of the control group. Therefore, we may imply that higher serum uric acid levels may be associated with renal impairment in lead-exposed subjects even in the earlier stages of exposure.