Blood superoxide dismutase and plasma malondialdehyde among workers exposed to asbestos

Blood superoxide dismutase (SOD) and plasma malondialdehyde (MDA) (an indicator of lipid peroxidation [LPO]) were determined in 97 randomly selected asbestos exposed workers (age range: 25–60 years, mean duration of exposures 19.8 ± 8.3 years) and in 42 healthy male controls. MDA, SOD, and MDA/SOD ratio in asbestos exposed workers were significantly higher than in controls. Among both the controls and exposed workers neither age nor smoking was related to SOD or MDA levels. SOD was significantly positively correlated with MDA among the exposed workers. Such correlation was not observed among the controls. SOD but not MDA was significantly positively correlated with the duration of exposure to asbestos. Mean levels of SOD or MDA in exposed workers with radiographic signs of lung fibrosis or pleural thickening did not differ significantly from those without such signs. The results confirm the possible involvement of LPO and development of anti-oxidant mechanism(s) of prolonged exposure to asbestos in humans. However, SOD seems not to be the essential anti-asbestos-induced LPO. Relation between these factors and lung fibrosis is still unclear.     

谷胱甘肽S-转移酶M1基因型与石棉作业工人血液脂质过氧化水平的关系

目的　探讨谷胱甘肽S 转移酶M1(GSTM1)基因型与接触石棉的工人血液发生脂质过氧化的关系。方法　选择 94名石棉作业工人及 5 1名对照工人作为研究对象 ,通过问卷调查收集每个研究对象的一般情况、职业史等。同时测定血浆丙二醛 (MDA)的含量 ,分析淋巴细胞DNA中GSTM1的基因型。结果　石棉作业工人血浆MDA含量为 (0 .2 83± 0 .0 5 4)nmol/L ,明显高于对照组工人 [(0 .16 3± 0 .0 5 3)nmol/L],差异有显著性 (P <0 .0 1) ,但MDA含量与工龄和累积石棉接触剂量之间的相关关系不明显 ;对照组工人携带GSTM1- /-者血浆中的MDA含量 [(0 .190± 0 .0 34 )nmol/L]明显高于携带GSTM1+/+者[(0 .138± 0 .0 5 5 )nmo/L],差异有显著性 (P <0 .0 1) ,而石棉作业工人组虽也有类似趋势 ,但无统计学差异 (P >0 .0 5 ) ;对于石棉作业工人来说 ,在工龄相同或累积石棉接触剂量相同时 ,携带GSTM1- /-者的血浆MDA含量均高于携带GSTM1+/+者 ,但差异均无显著性 (P >0 .0 5 )。结论　接触石棉和GSTM1- /-基因型均与作业工人机体内脂质过氧化有关 ,但石棉的作用可能大于GSTM1基因型的作用。     

采石工人血清脂质过氧化水平和抗氧化酶活性的研究

目的　探讨二氧化硅粉尘对人体作用中的脂质过氧化机制 ,寻求矽尘作业人员早期健康监测灵敏指标。方法　整群抽取 10 4名长期从事矽尘作业的采石工人和 10 1名无接尘、接毒史的健康工人为研究对象。分别测定血清中丙二醛 (MDA)、超氧化物歧化酶 (SOD)和谷胱甘肽过氧化物酶 (GSH Px)的含量并对其结果进行相应的统计分析。结果　接尘组血清MDA、SOD均高于对照组 ,而GSH Px则低于对照组 ,且均有统计学意义。 3项指标的异常检出率均高于对照组 ,其中MDA、SOD差异有显著性。接尘组MDA含量与SOD呈正相关 ,而与GSH Px呈负相关 ,3项指标均与累积接尘剂量有一定的相关。结论　二氧化硅粉尘可引起接触者体内脂质过氧化水平和抗氧化酶活性改变     

Ferruginous bodies and pulmonary fibrosis in dead low to moderately exposed asbestos cement workers: histological examination

Histological slides from the lungs of 89 dead asbestos cement workers have been examined with respect to ferruginous bodies and fibrosis. The results have been compared with individually matched controls with no known exposure to asbestos, and related to asbestos exposure, expressed as duration of exposure and cumulative asbestos dose, and smoking habits. The asbestos cement workers studied had been employed for on average 15 years, with a mean cumulative dose of 26 fibre-years per ml (f-y/ml). Clear dose-response relations between exposure (duration of exposure and cumulative asbestos dose) and level of ferruginous bodies were found. An association was evident already at a low cumulative dose (1-10 f-y/ml). Fibrosis was more common and more pronounced among the exposed workers than among controls. An association between ferruginous bodies and fibrosis was also found. Among the controls, but not among exposed workers, there was an association between smoking history and fibrosis.     

Ferruginous bodies and pulmonary fibrosis in dead low to moderately exposed asbestos cement workers: histological examination.

Histological slides from the lungs of 89 dead asbestos cement workers have been examined with respect to ferruginous bodies and fibrosis. The results have been compared with individually matched controls with no known exposure to asbestos, and related to asbestos exposure, expressed as duration of exposure and cumulative asbestos dose, and smoking habits. The asbestos cement workers studied had been employed for on average 15 years, with a mean cumulative dose of 26 fibre-years per ml (f-y/ml). Clear dose-response relations between exposure (duration of exposure and cumulative asbestos dose) and level of ferruginous bodies were found. An association was evident already at a low cumulative dose (1-10 f-y/ml). Fibrosis was more common and more pronounced among the exposed workers than among controls. An association between ferruginous bodies and fibrosis was also found. Among the controls, but not among exposed workers, there was an association between smoking history and fibrosis.     

Asbestos exposure and antineutrophil cytoplasmic Antibody (ANCA) positivity

The authors used indirect immunofluorescence to examine the association of antineutrophil cytoplasmic antibodies (ANCAs) with exposure to asbestos among 61 asbestos-exposed patients (mean exposure = 24.6 yr) and 39 nonexposed controls. ANCA positivity was detected significantly more frequently (p = 0.034) in the asbestos-exposed group (21.3%) than in the control group (5.1%). ANCA-associated diseases did not occur more frequently among subjects exposed previously to asbestos than among unexposed controls. These findings confirmed that exposure to asbestos is another occupational factor, as is silica exposure, that is associated with ANCA positivity. The influence of asbestos appears stronger than that of silica because ANCA positivity was found among subjects who had histories of exposure to asbestos but who did not exhibit typical radiographic signs of asbestosis on their chest x-rays. Additional stimuli may be necessary to induce systemic vasculitis in asbestos-exposed persons.     

Serum type III procollagen peptide in asbestos workers: an early indicator of pulmonary fibrosis

Serum type III procollagen peptide (PIIIP) concentrations were determined in 36 male workers exposed to asbestos fibres in the production of asbestos cement items and in 13 healthy male controls. Mean (SD) PIIIP serum concentrations were 9.3 (1.5) ng/ml (range 7-12) in the controls and 13.7 (3.5)ng/ml (range 7.5-20) in the asbestos workers; the difference was statistically significant (p less than 0.01). The exposed workers were subdivided according to presence or absence of radiological signs of asbestosis and intensity and duration of exposure. PIIIP serum values of workers with asbestos related interstitial fibrosis were the highest of the groups at 14.6 (2.3) ng/ml. In workers with heavy exposure the PIIIP values were significantly related to duration of exposure (r = 0.95; p less than 0.01). PIIIP serum values may be a useful index for the early diagnosis of asbestos induced pulmonary fibrosis and its use should be considered as part of the biological monitoring of exposed workers.     

Serum type III procollagen peptide in asbestos workers: an early indicator of pulmonary fibrosis.

Serum type III procollagen peptide (PIIIP) concentrations were determined in 36 male workers exposed to asbestos fibres in the production of asbestos cement items and in 13 healthy male controls. Mean (SD) PIIIP serum concentrations were 9.3 (1.5) ng/ml (range 7-12) in the controls and 13.7 (3.5)ng/ml (range 7.5-20) in the asbestos workers; the difference was statistically significant (p less than 0.01). The exposed workers were subdivided according to presence or absence of radiological signs of asbestosis and intensity and duration of exposure. PIIIP serum values of workers with asbestos related interstitial fibrosis were the highest of the groups at 14.6 (2.3) ng/ml. In workers with heavy exposure the PIIIP values were significantly related to duration of exposure (r = 0.95; p less than 0.01). PIIIP serum values may be a useful index for the early diagnosis of asbestos induced pulmonary fibrosis and its use should be considered as part of the biological monitoring of exposed workers.     

Asbestos Exposure and Antineutrophil Cytoplasmic Antibody (ANCA) Positivity

The authors used indirect immunofluorescence to examine the association of antineutrophil cytoplasmic antibodies (ANCAs) with exposure to asbestos among 61 asbestos-exposed patients (mean exposure = 24.6 yr) and 39 nonexposed controls. ANCA positivity was detected significantly more frequently (p = 0.034) in the asbestos-exposed group (21.3%) than in the control group (5.1%). ANCA-associated diseases did not occur more frequently among subjects exposed previously to asbestos than among unexposed controls. These findings confirmed that exposure to asbestos is another occupational factor, as is silica exposure, that is associated with ANCA positivity. The influence of asbestos appears stronger than that of silica because ANCA positivity was found among subjects who had histories of exposure to asbestos but who did not exhibit typical radiographic signs of asbestosis on their chest x-rays. Additional stimuli may be necessary to induce systemic vasculitis in asbestos-exposed persons.     

Radiologic abnormalities in South African mica millers: a survey of a mica milling plant in the Limpopo Province

All 73 workers at a South African mica milling plant were surveyed for radiographic evidence of abnormalities related to dust exposures at work. Chest x-rays were taken and questionnaires administered to determine occupational and environmental exposure histories. Dust levels to which workers were exposed were measured. All but one of 12 airborne inhalable and respirable dust levels were below the occupational exposure limits (OEL-RLs) of 10 mg/m3 and 5 mg/m3 respectively. The mica concentrations were below the OEL-RL of 1 mg/m3 for respirable mica. Mean age and service duration of the workers were 45 and 14 years, respectively. 19 workers (27%) had changes referable to their exposures to asbestos, mica, silica, or combinations. Of these, four showed additional radiographic changes in keeping with tuberculous lung scarring. Six had evidence of lung changes consistent with past tuberculosis alone. Rates of radiologic abnormalities were higher in older workers and those with longer service. An association between mica and radiologic changes could not be convincingly shown because of the nature of the survey and the co-exposure to other mineral dusts. Nevertheless, six workers had radiologic changes consistent with pneumoconiosis attributable to mica or the combination of mica and silica.     

金属镉作业人群的脂质过氧化与抗氧化能力的观察

目的 观察金属镉接触作业人群体内的脂质过氧化产物和抗氧化酶的变化。方法 选取91名接触金属镉（Cd）的作业人员为接触组，并以79名不接触任何毒物的健康人作为对照组，测定血清中丙二醛（MDA）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）和谷胱甘肽硫转移酶（GST）。结果 接触组的SOD、GSH-Px和GST的活性明显下降，而MDA明显增高（P〈0．05）。以工龄分组比较，显示长工龄组较短工龄组MDA高，SOD、GSH-Px和GST活性低（P〈0．05）。结论 Cd能增加体内脂质过氧化产物含量，降低机体的抗氧化能力，增加职业接触人群对氧化应激的易感性。     

煤矿粉尘接触和人群脂质过氧化水平的观察

目的 为了解煤矿粉尘接触和人群脂质过氧化水平。方法 检测煤矿粉尘接触量和人群脂质过氧化水平。结果 矿井巷道和采煤面粉尘浓度低于国家标准装渣,放炮作业和各工种一次最高浓度均超国标。除矿井出风口外,地面各监测点可吸入粉尘均在容许范围,粉尘接触人群ＳＯＤ活性降低,井下工人ＭＤＡ增加,吸烟者更显著,煤工尘肺患者两项指标同时提高,结论 提示煤尘接触引起人群脂质过氧化代谢紊乱,紊乱程度和粉尘接触量有关,吸烟是     

Lipid peroxidation in workers exposed to aluminium, gallium, indium, arsenic, and antimony in the optoelectronic industry

OBJECTIVE: The objective of this study was to investigate whether exposure to aluminum, gallium, indium, arsenic, and antimony induces lipid peroxidation in humans. METHODS: Whole blood and urine levels of 103 exposed electronic industry workers and 67 referents were analyzed by use of inductively coupled plasma mass spectrometry. Malondialdehyde (MDA), the product of lipid peroxidation, was determined by high-performance liquid chromatography. RESULTS: The mean plasma MDA level in the 103 workers was significantly higher than that in 67 referents. The levels of MDA in the exposed workers were correlated significantly with the levels of urinary gallium and arsenic. CONCLUSIONS: Malondialdehyde as an index of lipid peroxidation can be induced by gallium and arsenic exposure. By reducing exposure to these metals, biologic effects such as lipid peroxidation may also be diminished.     

Respiratory impairments due to dust exposure: A comparative study among workers exposed to silica,asbestos, and coalmine dust

We conducted a comparative study of pulmonary dysfunction among workers who were exposed to silica, asbestos, or coalmine dust. The results showed that all three groups of dust-exposed workers, even those without radiographic signs of pneumoconiosis, had decreased spirometric parameters and diffusing capacity (DLco) in both nonsmokers and smokers. Pulmonary function was further decreased when pneumoconioses were present in the three groups. In accord with increasing radiographic categories, pulmonary function in the workers' pneumoconiosis (CWP), it changed relatively little. Workers with mild to moderate (radiographic category I–II) silicosis or asbestosis showed similarly decreased DLco, but those with silicosis showed lower FEV₁/FVC than those with asbestosis. The workers with CWP also showed a lower FEV₁/FVC than those with asbestosis. The major impairment patterns for silica workers, asbestos workers, and coal miners were mixed, restrictive and mixed, and obstructive, respectively. Smoking obviously increased the prevalence of obstruction for all the groups. We conclude from the present study that all the three dusts cause functional abnormalities that precede radiographic changes of pneumoconiosis. We should pay more attention to respiratory impairment in the initial stage of silicosis and CWP. Am. J. Ind. Med. 31:495–502, 1997. © 1997 Wiley-Liss, Inc.     

Screening for asbestos-induced diseases in Finland

Screening for asbestos-induced diseases in Finland was carried out in 1990–1992 as a part of the Asbestos Program of the Finnish Institute of Occupational Health. The aim of the present study was to find the workers who had developed an asbestos-induced disease in certain occupations. Examination of active or retired workers included a personal interview on work history and asbestos exposure, and a chest X-ray. The target group for the screening comprised workers under 70 years of age who had worked at least for 10 years in construction, 1 year in a shipyard or in the manufacture of asbestos products. A preliminary questionnaire was sent to 54,409 workers, 18,943 of whom finally participated in the screening examination. The mean age of the workers was 53 years; 95% were employed in construction, 2% in shipyards, and 3% in the asbestos industry. The criteria for a positive screening result were (1) a radiographic finding clearly indicating lung fibrosis (at least ILO category 1/1), (2) a radiographic finding indicating mild lung fibrosis (ILO category I/O) with unilateral or bilateral pleural plaques, (3) marked abnormalities of the visceral pleura (marked adhesions with or without pleural thickening), or (4) bilateral pleural plaques. The positive cases totalled 4,133 (22%) and were sent for further investigation. In addition to the screening, information on the presence of asbestos in the work environment, prevention of asbestos exposure, as well as on the health effects of asbestos exposure and smoking were given to the participating workers. The screening acted as a preliminary survey to prompt further national follow-up of asbestos-induced diseases among the workers who have been exposed to asbestos. This article presents the material, methods, and overall results of the screening. © 1996 Wiley-Liss, Inc.     

Pulmonary function in long-term asbestos workers in China

The relationship of pulmonary function to exposure to asbestos and radiographic abnormalities has been controversial, especially when smoking is present as a confounder. The aim of the study was to provide further understanding on the radiographic-physiologic associations in nonsmoking and smoking asbestos workers. Radiographic asbestosis, pleural lesion, and pulmonary function were studied in 269 Chinese asbestos workers, with average exposure years of 23 for male workers and 18 for female workers. Their functional data were compared with those of 274 controls without exposure to dust. Although most of the male workers were smokers, none of the female workers smoked. In comparison with controls, asbestos workers had significantly lower lung volume and diffusing capacity, irrespective of gender. Female workers and smoking male workers had lower measurements of forced expiratory volume in 1 second and instantaneous forced expiratory flow at 50% and 25% of forced vital capacity. After adjustment for relevant covariates, asbestos exposure, asbestosis, and pleural abnormalities were associated with decreased parameters of pulmonary function, including lung volume, diffusing capacity, and airway flow. These data indicate that asbestos-related functional defects manifested by lung restriction and mild airway obstruction correlate with exposure to asbestos and with parenchymal and pleural abnormalities, independent of smoking.     

Respiratory symptoms and functional status in workers exposed to silica, asbestos, and coal mine dusts

This study aims to provide further understanding of physiologic and symptomatic changes and radiographic abnormalities due to exposure to silica, asbestos, and coal dusts. Questionnaires and pulmonary function tests were given to 220 silica, 277 asbestos, and 511 coal workers from three different industries in China. Posteroanterior chest radiographs were classified as stages 0, I, II, and III according to degree of parenchymal fibrosis. Significantly poorer pulmonary function and a higher prevalence of dyspnea and chronic cough were observed in workers with pneumoconiosis than those without, irrespective of dust type. Workers with stages II and III silicosis had worse pulmonary function and more common symptoms relative to workers with equivalent coal workers' pneumoconiosis or asbestosis. After adjusting for relevant confounders, reductions in the spirometric parameters and single breath diffusing capacity for carbon monoxide (DLCO) and the occurrence of respiratory symptoms were associated with increasing stage of silicosis, whereas lower DLCO and the occurrence of symptoms were associated with increasing stage of asbestosis and coal workers' pneumoconiosis. The study suggests that despite the differences in degree and pattern due to exposure to different fibrogenic dusts, respiratory impairments of all of the workers are associated with the presence and progression of parenchymal fibrosis and smoking.     

Radiographic abnormalities among construction workers exposed to quartz containing dust

Background: Construction workers are exposed to quartz containing respirable dust, at levels that may cause fibrosis in the lungs. Studies so far have not established a dose-response relation for radiographic abnormalities for this occupational group.

Aims: To measure the extent of radiographic abnormalities among construction workers primarily exposed to quartz containing respirable dust.

Methods: A cross sectional study on radiographic abnormalities indicative of pneumoconiosis was conducted among 1339 construction workers mainly involved in grinding, (jack)-hammering, drilling, cutting, sawing, and polishing. Radiological abnormalities were determined by median results of the 1980 International Labour Organisation system of three certified "B" readers. Questionnaires were used for assessment of occupational history, presence of respiratory diseases, and symptoms and smoking habits.

Results: An abnormality of ILO profusion category 1/0 and greater was observed on 10.2% of the chest radiographs, and profusion category of 1/1 or greater on 2.9% of the radiographs. The average duration of exposure of this group was 19 years and the average age was 42. The predominant type of small opacities (irregularly shaped) is presumably indicative of mixed dust pneumoconiosis. The prevalence of early signs of nodular silicosis (small rounded opacities of category 1/0 or greater) was low (0.8%).

Conclusions: The study suggests an elevated risk of radiographic abnormalities among these workers with expected high exposure. An association between radiographic abnormalities and cumulative exposure to quartz containing dust from construction sites was observed, after correction for potentially confounding variables.

     

Exposure to silica and risk of ANCA-associated vasculitis

BACKGROUND: Exposure to silica dust is considered to be one of etiological factors of antineutrophil cytoplasmic antibodies (ANCA) -associated vasculitis (AAV). METHODS: Subjects exposed to silica dust in Central Bohemia and followed in the Department of Occupational Medicine, Charles University, were selected for study. A group of 86 men exposed to SiO2 for at least 5 years were examined. The association between occupational exposure to silica dust and ANCA positivity is analyzed. RESULTS: The subjects had a mean age of 66.7 years, and mean exposure to silica of 22.3 years. ANCA were detected significantly more frequently in patients group (17.1%; P-ANCA 18x, C-ANCA 3x) than in controls (n = 28, mean age 64.2 years, P-ANCA 1x, i.e., 3.6%). ANCA positivity was found less frequently (7.1%) in the group with history of SiO2 exposure without signs of pronounced silicosis, than in the group with simple (30.3%) or complicated silicosis (36.0%). Odds ratio for ANCA positivity and relative risk estimate in patients with silicosis were highly significant. Among possible predictor factors for ANCA positivity, silicosis and tuberculosis were relevant. No typical AAV was present among the patients. CONCLUSION: Long-term silica exposure may be one of the exogenous factors contributing to ANCA production, however, silica exposure alone, without typical silicosis, was not associated with ANCA positivity.     

Relation between lung function, exercise capacity, and exposure to asbestos cement

A group of 137 male workers with known exposure (mean 20 fibre years per millilitre) to asbestos cement who had symptoms or signs of pulmonary disease was studied together with a reference group of 49 healthy industrial workers with no exposure to asbestos. Lung function measurements were made at rest and during exercise. Evidence of lung fibrosis was found as well as of obstructive airways disease in the exposed group compared with the reference group. Asbestos cement exposure was related to variables reflecting lung fibrosis but not to variables reflecting airflow obstruction. Smoking was related to variables reflecting obstructive lung disease. Exercise capacity was reduced in the exposed workers and was related to smoking and to lung function variables, reflecting obstructive airways disease. There was no significant correlation between exercise capacity and exposure to asbestos cement.