Benchmark dose estimation for coke oven emissions based on oxidative damage in Chinese exposed workers.

Coke oven emissions (COEs) can cause oxidative stress of the body, which in turn induces the occupational lung disease and also increases the risk of other diseases. COEs are the major occupational hazard factors for coke oven workers. The aim of the study is to explore the influences of COEs exposure on oxidative damage and estimate the benchmark dose (BMD) of COEs. A group of 542 workers exposed to COEs and 237 healthy controls from the same city were recruited in this study. The corresponding measuring kits were used to determine the plasma biomarkers of oxidative damage level. Generalized linear models and trend tests were used to analyze the relationship between COEs exposure and biomarkers. EPA Benchmark Dose Software was performed to calculate BMD and the lower confidence limit of the benchmark dose (BMDL) of COEs exposure. A significant association was observed between COEs exposure and oxidative damage with T-AOC as a biomarker. The BMD of COEs exposure were 2.83 mg/m3 and 1.39 mg/m3 for males and females, respectively, and the corresponding BMDL were 1.47 mg/m3 and 0.75 mg/m3, respectively. Our results suggested that the exposure level of COEs below the current national occupational exposure limits (OELs) would induce oxidative damage, and the OEL of COEs based on the T-AOC damage was suggested at 0.03 mg/m3 in this study.

Morphological features of pulmonary fibrosis in workers occupationally exposed to alpha radiation.

Purpose: The article reports on a comparative analysis of biological specimens of lung tissues collected from workers with pulmonary fibrosis induced by internal exposure to plutonium alpha-particles (plutonium-induced pulmonary fibrosis [PuPF]) and with etiologically different pulmonary fibrosis (non-PuPF) that developed as an outcome of a chronic obstructive pulmonary disease (COPD).Materials and methods: To perform histological examinations, lung tissues were sampled during autopsy. Six samples of various lung regions (the apical region, the lingula of the left lung and the inferior lobe) were collected from each donor. The resected tissue samples were fixed in 10% neutral-buffered formalin during 24 h and embedded into paraffin blocks (FFPE). FFPE blocks with lung tissue specimens collected from 56 workers with PuPF, 34 workers with non-PuPF and 35 workers without any lung disease were used in the study. To perform microscopic examination, lung tissue specimens were hematoxylin and eosin stained. To examine the connective-tissue scaffold of lung stroma and identify foci of pulmonary fibrosis, the cut sections of paraffin blocks were stained by Van Gizon's method (to assess the total volume of fibrosis-affected tissues), Gomori's technique (to define the reticular scaffold of lung stroma) and Weigert's technique (to examine elastic fibers). Morphological patterns of all biological specimens were studied using immunohistochemistry. To fit the empirical data, the Weibull's model was used.Results and conclusions: The study found qualitative and quantitative morphological features specific for PuPF compared to non-PuPF. The study demonstrated that hyper-production of collagen type V plays a key role in PuPF. The collagen type V content in fibrotic foci in lung tissue specimens from workers with PuPF was found to be increased.

Estimation of Total Skeletal Content of Plutonium and 241Am From Analysis of a Single Bone.

The skeleton is one of the major retention sites for internally deposited actinides. Thus, an accurate estimation of the total skeleton content of these elements is important for biokinetic modeling and internal radiation dose assessment. Data from 18 whole-body donations to the US Transuranium and Uranium Registries with known plutonium intakes were used to develop a simple and reliable method for estimation of plutonium and Am activity in the total skeleton from single-bone analysis. A coefficient of deposition Kdep, defined as the ratio of actinide content in the patella to that in the skeleton, was calculated for Pu, Pu, and Am. No statistical difference was found in Kdep values among these radionuclides. Variability in Kdep values was investigated with relation to skeleton pathology (osteoporosis). The average Kdep of 0.0051 ± 0.0009 for the osteoporotic group was statistically different from Kdep of 0.0032 ± 0.0010 for nonosteoporotic individuals. The use of Kdep allows for rapid estimation of the total skeletal content of plutonium and Am with up to 35% uncertainty. To improve accuracy and precision of total skeleton activity estimates, regression analysis with power function was applied to the data. Strong correlation (r > 0.9) was found between Pu, Pu, and Am activities measured in the patella bone and total skeleton activity. The results of this study are specifically important for the optimization of bone sample collection for US Transuranium and Uranium Registries partial-body donations.

Impact of occupational cadmium exposure on bone in sewage workers.

Cadmium (Cd) is one of the environmental risk factors for bone loss. The present study included 40 sewage workers occupationally exposed to Cd. Forty nonexposed men were included as a control group. Current smokers represented 65% and 47.5% of the exposed and control groups, respectively. The study aimed to investigate the hazard of occupational Cd exposure on bone health. This was achieved through measuring serum and urinary Cd, and calcium (Ca), in addition to serum osteoprotegerin (OPG) and estrogen receptor-α gene. Results showed significant elevation in serum Cd, OPG, and urinary Ca levels in the exposed compared to the controls. Bony aches and joint pain were more prevalent among the exposed workers. Serum and urinary Cd increased in exposed smokers relative to control smokers. Also, serum OPG levels showed significant rise among exposed smoker and nonsmoker compared to control smoker and nonsmoker groups. Serum Cd level increased significantly in PP and pp genotypes in exposed workers compared to controls, while elevated levels of serum OPG was observed in PP and Pp genotypes in exposed workers relative to controls. Urinary Cd exhibited significant rise in both PP and pp genotypes in exposed workers, while Ca excretion was elevated in pp genotype only. The study reflected an association of genetic predisposition and Cd exposure in progression of osteoporosis. Further research is needed to explain the mechanisms of Cd impact on bone. The role of smoking is important and hence smoking cessation programs are essential for sewage workers.

The neuro-ophthalmological effects related to long-term occupational exposure to organic solvents in painters.

PURPOSE: Organic solvents are widely used in many industries, and usually, exposure occurs with mixtures of solvents. Organic solvent mixtures are known for their ability to affect tissues of high lipid content including the myelin sheath in the nervous system. The purpose of this work was to study the evidence that long-term (more than 10 years) exposure to organic solvent mixtures among painters can induce neuro-ophthalmological effects on the function of retinal ganglion cells and the optic tract. METHODS: Twenty workers with long-term occupational exposure to mixed organic solvents were compared to 40 control subjects. The controls were matched for age, gender, and demographic characteristics but were not occupationally exposed to any known organic solvents, using the following comparators: visual evoked potential (VEP), electroretinogram (ERG), color vision (CV), and contrast sensitivity (CS) testing. Environmental monitoring was done in the work environment with consideration to the American Conference of Governmental Industrial Hygienists Threshold Limit Values (ACGIH-TLVs). RESULTS: The exposed group had significantly longer latency and higher amplitude of VEP waves especially P100, higher Color Confusion Index (CCI), especially affecting the blue-yellow spectrum, and lower Log CS. There was no significant difference between exposed and nonexposed groups in full-field flash ERG response; however, in the pattern ERG, the exposed group had significantly longer latency of P50, which reflects changes in the retinal ganglion cell. CONCLUSION: Long-term occupational exposure to mixed organic solvents appeared to affect the optic tract functions in the form of increasing latency of VEP response, affecting the quality of CV and decreasing CS. It also affects the retinal ganglion cell layer with increased latency of P50 of the pattern ERG response.

Comparison of biomarkers in serum and induced sputum of patients with occupational asthma and chronic obstructive pulmonary disease.

OBJECTIVES: Occupational asthma and chronic obstructive pulmonary disease (COPD) are associated with the airway inflammatory process. The aim of this study was to compare the sputum and serum markers of inflammation in patients with occupational asthma and COPD. METHODS: The study group included 20 patients with stable COPD, 24 patients with asthma, and 22 healthy subjects. Interleukin (IL)-6, IL-1ß, tumor necrosis factor (TNF)-α, matrix metalloproteinase (MMP)-9 levels in serum and induced sputum as well as fibrinogen and CRP in serum were determined in all the subjects. RESULTS: Higher concentrations of IL-1ß, IL-6, TNF-α, and MMP-9 in induced sputum and an increased concentration of acute-phase proteins in serum were observed in COPD patients compared with healthy subjects. Higher concentrations of IL-1ß and MMP-9 in induced sputum and a higher concentration of C-reactive protein (CRP) were detected in COPD patients than in asthmatic subjects. Never smokers with COPD had significantly higher levels of IL-1ß and MMP-9 in induced sputum than never smoker controls. There was no significant difference between the serum and sputum levels of cytokines and MMP-9 of never smokers and smokers with COPD. CONCLUSIONS: Higher concentrations of IL-1ß and MMP-9 in induced sputum and a higher concentration of CRP in serum allow distinguishing between biomarker profiles of COPD patients and asthmatic patients. Occupational exposure induces a systemic proinflammatory state with increased levels of acute-phase proteins in stable COPD patients. MMP-9 and IL-1ß concentrations are increased in induced sputum of never smokers with COPD, which is associated with occupational exposure.

Protein profiles of nasal lavage fluid from individuals with work-related upper airway symptoms associated with moldy and damp buildings.

Upper airway irritation is common among individuals working in moldy and damp buildings. The aim of this study was to investigate effects on the protein composition of the nasal lining fluid. The prevalence of symptoms in relation to work environment was examined in 37 individuals working in two damp buildings. Microbial growth was confirmed in one of the buildings. Nasal lavage fluid was collected from 29 of the exposed subjects and 13 controls, not working in a damp building. Protein profiles were investigated with a proteomic approach and evaluated by multivariate statistical models. Subjects from both workplaces reported upper airway and ocular symptoms. Based on protein profiles, symptomatic subjects in the two workplaces were discriminated from each other and separated from healthy controls. The groups differed in proteins involved in inflammation and host defense. Measurements of innate immunity proteins showed a significant increase in protein S100-A8 and decrease in SPLUNC1 in subjects from one workplace, while alpha-1-antitrypsin was elevated in subjects from the other workplace, compared with healthy controls. The results show that protein profiles in nasal lavage fluid can be used to monitor airway mucosal effects in personnel working in damp buildings and indicate that the profile may be separated when the dampness is associated with the presence of molds.

Usefulness of biomarkers as intermediate endpoints in health risks posed by occupational lead exposure.

The article concerns potential harmful effects of exposure to lead. Although the occurrence of severe lead poisoning has receded in several countries, occupational exposure resulting in moderate and clinically symptomatic toxicity is still common. An earlier and precise characterization of an individual response is obligatory in order to assess the possible risks for human health. Biomarkers may fill important gaps in the path from exposure to a disease. Specifically speaking, emerging (DNA double strand breaks and telomeric DNA erosion) and validated (micronuclei induction and chromosomal aberrations) biomarkers of genotoxicity seem to provide evidence for the assessment of molecular and cellular damage. Moreover, identification of genetic variability with a key role in modulating genotoxic damage may help minimize risks for susceptible subjects. Further investigations are naturally needed to properly define their diagnostic and/or prognostic value as "early warning" signs of a long-term risk for a subsequent clinically overt disease.

[Serum cystathionine ß-synthase (CBS), cystathionine γ-lyase (CSE ) and cytochrome c oxidase (COX) in copper mine miners potentially expose d to hydrogen sulfide]. / ß-syntaza cystationiny (CBS), γ-liaza cystationiny (CSE) i oksydaza cytochromu c (COX) w surowicy górników kopalni miedzi potencjalnie narazonych na emisje siarkowodoru.

BACKGROUND: The aim of the study was to evaluate serum levels of the target enzyme for H2S toxicity--cytochrome c oxidase (COX) and enzymes involved in the synthesis of H2S--cystathionine ß-synthase (CBS) and cystathionine γ-lyase (CSE) in copper mine miners. MATERIAL AND METHODS: The initial and basic study was conducted respectively in 237 and 88 miners, working in 2 mining shafts: I--no H2S emissions recorded in the last 10 years (study group A) and II--H2S emissions occurred (study group B). A medical examination was performed and 10 ml of blood was collected from miners immediately after exiting the mine. RESULTS: There were no clinical or biochemical changes typical for H2S toxicity. Sulfhemoglobine was undetectable and there were no changes in the red-ox system. However, in group B, regulatory changes were found; a tendency to higher concentration of CBS and CSE, a higher activity of angiotensin converting enzyme (ACE) compared to group A (p<0.05) and a linear relationship between ACE and CSE (r=0.6927; p<0.001). It has been shown that cigarette smoking decreases COX (p<0.05), however, in miners working in shaft II, the decreased level of COX may result also from the presence of H2S in the gaseous emissions. CONCLUSIONS: COX concentration can be a sensitive indicator of exposure to H2S. The measurements of blood H2S concentrations carried out in workplaces should explain the cause of the changes observed in the COX, CBS and CSE activity.

Occupational exposure to diisocyanates in polyurethane foam factory workers.

OBJECTIVES: The aim of the study was to evaluate health effects of occupational exposure to diisocyanates (DIC) among polyurethane foam products factory workers. MATERIAL AND METHODS: Thirty workers had a physical examination, skin prick tests with common allergens, allergen-specific immunoglobulin E (IgE) antibodies to diisocyanates and pulmonary function tests. Concentrations of selected isocyanates in the workplace air samples as well as concentration of their metabolites in the urine samples collected from the workers of the plant were determined. RESULTS: The most frequent work-related symptoms reported by the examined subjects were rhinitis and skin symptoms. Sensitization to at least 1 common allergen was noted in 26.7% of the subjects. Spirometry changes of bronchial obstruction of a mild degree was observed in 5 workers. The specific IgE antibodies to toluene diisocyanate (TDI) and 4,4'-methylenebis(phenyl isocyanate) (MDI) were not detected in any of the patients' serum. Cellular profiles of the collected induced sputum (ISP) did not reveal any abnormalities. Air concentrations of TDI isomers ranged 0.2-58.9 µg/m3 and in 7 cases they exceeded the Combined Exposure Index (CEI) value for those compounds. Concentrations of TDI metabolites in post-shift urine samples were significantly higher than in the case of pre-shift urine samples and in 6 cases they exceeded the British Biological Monitoring Guidance Value (BMGV - 1 µmol amine/mol creatinine). We didn't find a correlation between urinary concentrations of TDI, concentrations in the air and concentrations of toluenediamine (TDA) in the post shift urine samples. Lack of such a correlation may be an effect of the respiratory protective equipment use. CONCLUSIONS: Determination of specific IgE in serum is not sensitive enough to serve as a biomarker. Estimation of concentrations of diisocyanate metabolites in urine samples and the presence of work-related allergic symptoms seem to be an adequate method for occupational exposure monitoring of DIC, which may help to determine workers at risk as well as to recognize hazardous workplaces.

[DISSOCIATION OF DISORDERS OF CARBOHYDRATE AND LIPID METABOLISM IN ALUMINUM INDUSTRY WORKERS ACCORDING TO MEDICAL EXAMINATION DATA].

There were analyzed results of a periodical medical examination of 396 aluminum plant workers. There was established the significant dissociation of carbohydrate and lipid metabolism indices in people contacting with elevated concentrations qf inorganic fluorine compounds as compared to control group of patients which were not exposed to the toxic chemicals. This can testify to the risk of early onset of diabetes mellitus type 2 for aluminum industry workers and to the necessity of the implementation of timely measures for this worker category.

Toluene diisocyanate: Induction of the autotaxin-lysophosphatidic acid axis and its association with airways symptoms.

Diisocyanates are industrial chemicals which have a wide range of applications in developed and developing countries. They are notorious lung toxicants and respiratory sensitizers. However, the mechanisms behind their adverse effects are not adequately characterized. Autotaxin (ATX) is an enzyme producing lysophosphatidic acid (LPA), and the ATX-LPA axis has been implicated in lung related inflammatory conditions and diseases, including allergic asthma, but not to toxicity of environmental low-molecular-weight chemicals. We investigated effects of toluene diisocyanate (TDI) on ATX induction in human lung epithelial cell models, and we correlated LPA-levels in plasma to biomarkers of TDI exposure in urine collected from workers exposed to <5ppb (parts per billion). Information on workers' symptoms was collected through interviews. One nanomolar TDI robustly induced ATX release within 10min in vitro. A P2X7- and P2X4-dependent microvesicle formation was implicated in a rapid ATX release and a subsequent protein synthesis. Co-localization between purinergic receptors and ATX was documented by immunofluorescence and confocal microscopy. The release was modulated by monocyte chemoattractant protein-1 (MCP-1) and by extracellular ATP. In workers, we found a dose-response relationship between TDI exposure biomarkers in urine and LPA levels in plasma. Among symptomatic workers reporting "sneezing", the LPA levels were higher than among non-symptomatic workers. This is the first report indicating induction of the ATX-LPA axis by an environmental low-molecular-weight chemical, and our data suggest a role for the ATX-LPA axis in TDI toxicity.

[State of lipid peroxidation in workers engaged into chrysotile-asbestos production].

To study influence of chrysotile-asbestos dust on health of asbestos production workers, the authors conducted biochemical study of serum lipids peroxidation in workers of mining transport enterprise and ore-dressing complex, in accordance with length of service. According to comparative analysis of the resuts obtained, the workers of mining transport enterprise and ore-dressing complex demonstrate more active lipid peroxidation with longer length of service, more pronounced in ore-dressing complex workers.

Scintigraphic assessment of renal function in steel plant workers occupationally exposed to lead.

OBJECTIVES: Occupational exposure to lead may produce kidney damage, but existing data on the dose range associated with nephrotoxicity are inconclusive. We here assessed renal function under conditions of low to moderate lead exposure using renal scintigraphy. METHODS: Fifty-three male foundrymen (exposed group) and fourty male office workers (control group) from a steel plant were included in the study. Glomerular and tubular renal function were assessed by means of (99m)Tc-DTPA and (99m)Tc-EC clearance, respectively. Urinary markers of glomerular dysfunction (albumin) and tubular damage (α1-microglobulin (α1M), ß2-microglobulin (ß2M), retinol-binding protein (RBP), N-acetyl-ß-glucosaminidase (NAG) activity) were determined using latex beads tests or colorimetry. The lead concentration in blood was measured with atomic absorption spectrometry. RESULTS: The blood lead concentrations were 145.8 (121.3-175.3) and 39.3 (35.1-44.1) µg/l (geometric mean, 95(th) CI, p<0.001) in the exposed and control groups, respectively. Subjects exposed to lead presented with increased (99m)Tc-DTPA clearance (158.3 (148.4-168.8) vs. 135.9 (127.9-144.4) ml/min; p<0.01) and urinary albumin excretion (7.61 (6.28-9.22) vs. 4.78 (4.05-5.65) mg/g creatinine; p<0.001). (99m)Tc-EC clearance and excretion of α1M, ß2M, RBP and NAG were not significantly different between the groups. Significant correlations between (99m)Tc-DTPA clearance and blood lead concentrations (r=0.45; p<0.01) and between urinary albumin excretion and blood lead concentrations (r=0.71; p<0.001) were noted. CONCLUSIONS: Use of renal scintigraphy in present study revealed measurable alterations of renal function under the conditions of low-level lead exposure and suggest that increased glomerular filtration may be an early indicator of kidney damage in subjects occupationally exposed to lead.

Importance of tear film instability in dry eye disease in office workers using visual display terminals: the Osaka study.

PURPOSE: To evaluate the relationship between subjective symptoms and clinical signs in dry eye disease (DED) in office workers using visual display terminals (VDTs). DESIGN: Cross-sectional study. METHODS: This study involved 672 Japanese young and middle-aged office workers who use VDTs. The subjects completed questionnaires designed to detect subjective symptoms and risk factors for DED. Dry eye tests, including tear film break-up time (TBUT), corneal-conjunctival staining with fluorescein and lissamine green, and the Schirmer test, were performed. Based on the Japanese diagnostic criteria for DED, the subjects were classified into 3 groups: definite DED, probable DED, and non-DED. Between each group, subjective symptoms and clinical signs were compared. RESULTS: Of the 672 subjects, 561 (374 male, 187 female) completed the questionnaire (response rate: 83.5%). Definite DED was diagnosed in 65 subjects (11.6%), probable DED in 303 subjects (54.0%), and non-DED in 193 subjects (34.4%). The mean subjective symptom score was significantly less in subjects with probable DED (2.05 ± 0.42) and non-DED (1.63 ± 0.38) than in those with definite DED (2.19 ± 0.40) (P < .05 and P < .01, respectively). In the subjects with probable DED, a subgroup with positive subjective symptoms and abnormal TBUT (≤5 seconds) was categorized as short TBUT-type DED, and it was found that they had a higher subjective symptom score (2.09 ± 0.40), equivalent to that of those with definite DED (P = .269). CONCLUSIONS: Despite no or minor epithelial damage, the severity of subjective symptoms was greater in short TBUT-type DED, most likely attributable to tear film instability. Thus, it might prove important to evaluate TBUT to successfully treat those patients.

An exploratory study of the effects of occupational exposure to physical demands on biomarkers of cartilage and muscle damage.

Biomarkers of tissue damage, derived from tissues commonly injured as a result of occupational physical demands, may be of use for future prediction of work-related musculoskeletal disorders (WMSDs). This exploratory study assessed whether selected biomarkers are likely to be sensitive to the level of occupational physical demands. Twenty-four participants were recruited to form two groups, with relatively high and low levels of WMSD risk. Serum levels of Cartilage Oligomeric Matrix Protein (COMP), Interleukin-6 (IL6), and Creatine Kinase (CK)--which respectively indicate cartilage damage, muscle use, and muscle damage--were obtained,. Six blood samples were obtained before and after work on Monday, Wednesday, and Friday of one working week. Additionally, a self-report measure of risk factor exposure, the Hollmann Index, was used to, and did, confirm group differences in WMSD risk. COMP levels varied significantly over time, but not between groups. IL6 levels were greater in the high-risk group at all time points and varied significantly over time and between groups. CK levels did not vary significantly over time or between groups. IL6 successfully differentiated between the high and low risk groups, suggesting potential use in the occupational domain. Prospective studies are needed, though, to associate biomarker levels/changes with WMSD risk.

Change in tear film characteristics in visual display terminal users.

PURPOSE: To evaluate changes in symptoms and tear film characteristics in young computer users. METHODS: Fifty-one computer users and 26 controls were evaluated at the beginning and the end of the working day. Subjects with ocular or systemic disease, history of ocular surgery, use of contact lenses or glasses with antireflective surfaces, and use of topical or systemic medications were excluded from the study. Computer use duration, Ocular Surface Disease Index (OSDI) questionnaire, tear osmolarity, Schirmer test, tear break-up time (TBUT), and ocular surface vital dye staining were performed prevocationally and postvocationally. RESULTS: The mean age was 31.2 ± 6.3 years in computer users and 33.7 ± 5.8 in controls. The mean reported computer use was 6.9 ± 2.7 hours/day in computer users and 0.4 ± 0.5 hours/day in controls. The mean prevocational and postvocational values in computer users for OSDI, osmolarity, TBUT, and Schirmer test were 23.2 ± 16.6 and 27.0 ± 17.6, 306.6 ± 14.9 and 311.0 ± 12.5 mOsm/L, 13.9 ± 4.0 and 13.2 ± 3.8 seconds, 22.7 ± 11.8 and 20.6 ± 12.5 mm, respectively. The vocational change was significant for all parameters in the computer user group but not in the control group. The osmolarity-based dry eye diagnosis was 27.4% in the computer users while it was 15.4% in the control group. Oxford score was only grade 1 in 5.9% of visual display terminal users and did not change at the end of the day. CONCLUSIONS: Both symptoms and signs of dry eye increased significantly with computer use. Approximately 1 of every 3-4 computer users was found to have dry eye with higher tear osmolarity values.

The effect of occupational lead exposure on lipid peroxidation, protein carbonylation, and plasma viscosity.

The aim of the study was to investigate the influence of occupational lead (Pb) exposure on lipid peroxidation, protein carbonylation, and plasma viscosity in workers. The examined group included 283 healthy male employees of manufacturing facilities using zinc and Pb. The mean blood concentrations of Pb and zinc protoporphyrin as well as the mean urine δ-aminolevulinic acid levels were used as markers of exposure for the examined group. Taking into account the obtained mean values of blood lead level, the examined group was divided into three subgroups. When comparing the control group with the subgroups, Pb exposure markers were significantly elevated in all the three subgroups. Concentrations of conjugated dienes (CD), lipid hydroperoxides, malondialdehyde (MDA), and protein carbonyl groups were also significantly increased. Conversely, the levels of total protein and protein sulfhydryls were significantly decreased in the subgroups compared with the controls. The plasma viscosity was significantly elevated in the subgroups. A dose-response between Pb levels and plasma viscosity was not observed. Pb supposedly elevates MDA and CD in a dose-dependent manner. In conclusion, occupational Pb exposure induces oxidative stress that results in lipid and protein damage. Moreover, Pb-induced oxidative stress is likely the primary factor that elevates plasma viscosity, despite decreased protein levels.

Occupational and environmental lead exposure to adolescent workers in battery recycling workshops.

Lead (Pb), as other environmental neurotoxicant substances, has the capability to interfere with many biochemical events present in cells throughout the body. In the present study, the environmental and occupational exposure to Pb has been assessed by analyzing the scalp hair samples of male adolescents aged 12-15 years, who have worked for the last 12-36 months in Pb battery recycling workshops (BRWs). For comparative purposes, gender and age-matched subjects living in the vicinity of recycling workshops as well as in areas without industrial activity were used as controls. The scalp hair samples were oxidized by acid in a microwave oven prior to determination of Pb by electrothermal atomic absorption spectrometry. The results indicated that both workers and nonworking exposed subjects had higher levels of Pb than nonexposed controls. The contents of Pb in scalp hair of adolescent workers in the present study were compared with those reported in other studies.

Reduced pulmonary function and increased pro-inflammatory cytokines in nanoscale carbon black-exposed workers.

BACKGROUND: Although major concerns exist regarding the potential consequences of human exposures to nanoscale carbon black (CB) particles, limited human toxicological data is currently available. The purpose of this study was to evaluate if nanoscale CB particles could be responsible, at least partially, for the altered lung function and inflammation observed in CB workers exposed to nanoscale CB particles. METHODS: Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Brunauer-Emmett-Teller were used to characterize CB. Eighty-one CB-exposed male workers and 104 non-exposed male workers were recruited. The pulmonary function test was performed and pro-inflammatory cytokines were evaluated. To further assess the deposition and pulmonary damage induced by CB nanoparticles, male BALB/c mice were exposed to CB for 6 hours per day for 7 or 14 days. The deposition of CB and the pathological changes of the lung tissue in mice were evaluated by paraffin sections and TEM. The cytokines levels in serum and lung tissue of mice were evaluated by ELISA and immunohistochemical staining (IHC). RESULTS: SEM and TEM images showed that the CB particles were 30 to 50 nm in size. In the CB workplace, the concentration of CB was 14.90 mg/m³. Among these CB particles, 50.77% were less than 0.523 micrometer, and 99.55% were less than 2.5 micrometer in aerodynamic diameter. The reduction of lung function parameters including FEV1%, FEV/FVC, MMF%, and PEF% in CB workers was observed, and the IL-1ß, IL-6, IL-8, MIP-1beta, and TNF- alpha had 2.86-, 6.85-, 1.49-, 3.35-, and 4.87-folds increase in serum of CB workers, respectively. In mice exposed to the aerosol CB, particles were deposited in the lung. The alveolar wall thickened and a large amount of inflammatory cells were observed in lung tissues after CB exposure. IL-6 and IL-8 levels were increased in both serum and lung homogenate. CONCLUSIONS: The data strongly suggests that nanoscale CB particles could be responsible for the lung function reduction and pro-inflammatory cytokines secretion in CB workers. These results, therefore, provide the first evidence of a link between human exposure to CB and long-term pulmonary effects.