新疆高原石棉作业工人肺功能调查

对新疆某高原石棉矿191名接尘作业工人和生活区69名非接尘工人进行了肺功能检查。结果表明：高原石棉矿接尘工人与非接尘工人各项测试指标均偏高，接尘工人肺功能随接尘工龄的增加而逐步下降，病例组肺功能异常率高于其它组，肺功能异常与吸烟关系不明显。     

Lung function and chest radiograph abnormalities among construction insulators.

We carried out a prevalence survey of pulmonary health parameters among current and retired construction insulators (50 years old and older) from all areas of British Columbia, Canada. The study population included 59 active workers (81 percent participation in this group) and 29 workers who were retired or inactive due to illness (69% participation). Radiograph results were compared to those from actively working bus mechanics from the same age group, and retired grain and civic workers, who were all tested in the same manner. Chest radiographs were read independently by two readers and were graded according to the ILO classification system. Pleural abnormalities alone were found in 34% (20) of active workers (5% in comparison group) and 45% (13) of non-active workers (14% in comparison group). Rates for parenchymal abnormalities for these same groups (ILO grade 1/0 or higher) were 17% (5%) and 20% (5%), respectively. Airflow obstruction was present in 35% (31) of the insulators and was associated with age and the presence of diffuse pleural thickening, and 5 or more years of employment in pulp mills. Restrictive lung function was present in 22% (19) of the insulator population and was associated with age and radiographic evidence of parenchymal fibrosis. The results indicate that construction insulators, a group at high risk for asbestos-related lung disease, also have a high prevalence of airflow obstruction. This was associated not only with smoking, but also with diffuse pleural thickening and a history of pulp-mill employment, suggesting that airflow obstruction in this population is also partly work related.     

Biological durability and oxidative potential of a stonewool mineral fibre compared to crocidolite asbestos fibres

Experiments are described concerning the differences in redox properties and biodurability of natural asbestos fibres and an experimental stonewool fibre incubated in Gamble solution and reconstructed surfactant fluid. Crocidolite exhibits a significantly higher oxidative potential compared to the tested stonewool fibres. The oxidative acitivity of both types of fibres is not constant during incubation over several weeks, but rather shows a sinoidal curve including reactivities much higher than those at the beginning of the incubation. A continuous loss of mass is concluded not to be definitively connected with a continuous loss of toxicity. Received: 19 November 1996 / Accepted: 27 March 1997     

Cooperative stimulation by sulfite and crocidolite asbestos fibres of enzyme catalyzed production of reactive oxygen species

Methylthioketobutyric acid has been used as an indicator for the production of reactive oxygen species during incubation with xanthine oxidase or NADH diaphorase in the presence of an autooxidizable quinone. The production of OH-radical-type oxidants is enhanced in the presence of crocidolite but not by the asbestos types chrysotile or amosite. This activity of crocidolite in the diaphorase system is further stimulated by bisulfite. Crocidolite-dependent ethylene formation from methylthioketobutyric acid is inhibited by both superoxide dismutase and catalase. In the presence of both crocidolite and bisulfite, however, the inhibition by superoxide dismutase is preserved, but the inhibition by catalase is lost. Since in some respect the NADH-diaphorase quinone system may reflect the situation in the activated macrophage, crocidolite activation may represent a biochemical model system describing potential asbestos toxicity.Abbreviations SOD Superoxide dismutase - KMB methylthioketobutyrate - XOD xanthine oxidase     

石棉诱发大鼠间皮瘤的超微结构及免疫组织化学研究

作者对23例大鼠间皮瘤作了超微结构研究,其中7例混合型作了免疫组化研究。结果说明,间皮瘤可能来自间皮下多功能的原始间叶细胞。作者还就本组间皮瘤与人和其他动物的间皮瘤进行了比较,并对电镜及免疫组化在研究间皮瘤中的作用进行了讨论。     

Risk factors for lung cancer in Iowa women: implications for prevention

BACKGROUND: Multiple risk factors possibly associated with lung cancer were examined as part of a large-scale residential radon case-control study conducted in Iowa between 1994 and 1997. We were particularly interested in stratifying risk factors by smoking status. Relatively little risk factor information is available for Midwestern rural women. METHODS: Four hundred thirteen female lung cancer cases and 614 controls aged 40-84, who were residents of their current home for at least 20 years, were included. Risk factors examined included cigarette smoking, passive smoking, occupation, chemical exposure, previous lung disease, family history of cancer, and urban residence. Multiple logistic regression analysis was conducted after adjusting for age, education, and cumulative radon exposure. RESULTS: As expected, active cigarette smoking was the major risk factor for lung cancer. While cessation of smoking was significantly associated with a reduced risk for lung cancer, the risk remained significantly elevated for 25 years. Among all cases, asbestos exposure was a significant risk. Among ex-smokers, pack-year history predominated as the major risk. Among never smokers, a family history of kidney or bladder cancer were significant risk factors (OR=7.34, 95% CI=1.91-28.18; and OR=5.02, 95% CI=1.64-15.39, respectively), as was a history of previous lung disease (OR=2.28, 95% CI=1.24-4.18) and asbestos exposure. No statistically significant increase in lung cancer risk was found for occupation or urban residence. CONCLUSIONS: Smoking prevention activities are urgently needed in rural areas of the United States. Relatives of individuals with smoking-related cancers are potentially at increased risk. Genetic risk factors should be more fully investigated in never smokers.     

The health effects of chrysotile: current perspective based upon recent data

This review substantiates kinetically and pathologically the differences between chrysotile and amphiboles. The serpentine chrysotile is a thin walled sheet silicate while the amphiboles are double-chain silicates. These different chemistries result in chrysotile clearing very rapidly from the lung (T(1/2)=0.3 to 11 days) while amphiboles are among the slowest clearing fibers known (T(1/2)=500 days to infinity). Across the range of mineral fiber solubilities chrysotile lies towards the soluble end of the scale. Chronic inhalation toxicity studies with chrysotile in animals have unfortunately been performed at very high exposure concentrations resulting in lung overload. Consequently their relevance to human exposures is extremely limited. Chrysotile following subchronic inhalation at a mean exposure of 76 fibers L>20 microm/cm(3) (3413 total fibers/cm(3)) resulted in no fibrosis (Wagner score 1.8-2.6), at any time point and no difference with controls in BrdU response or biochemical and cellular parameters. The long chrysotile fibers were observed to break apart into small particles and smaller fibers. Toxicologically, chrysotile which rapidly falls apart in the lung behaves more like non-fibrous mineral dusts while response to amphibole asbestos reflects its insoluble fibrous structure. Recent quantitative reviews of epidemiological studies of mineral fibers have determined the potency of chrysotile and amphibole asbestos for causing lung cancer and mesothelioma in relation to fiber type have also differentiated between these two minerals. The most recent analyses also concluded that it is the longer, thinner fibers that have the greatest potency as has been reported in animal inhalation toxicology studies. However, one of the major difficulties in interpreting these studies is that the original exposure estimates rarely differentiated between chrysotile and amphiboles. Not unlike some other respirable particulates, to which humans are, or have been heavily occupationally exposed, there is evidence that heavy and prolonged exposure to chrysotile can produce lung cancer. The value of the present and other similar studies is that they show that low exposures to pure chrysotile do not present a detectable risk to health. Since total dose over time decides the likelihood of disease occurrence and progression, they also suggest that the risk of an adverse outcome may be low if even any high exposures experienced were of short duration.     

Effect of quartz and asbestos on erythrocyte surface charge

Summary Experiments in vitro have been conducted to determine the surface-charge density of human red cells incubated with 7 quartz varieties as well as the UICC asbestos dusts: chrysotiles A and B, anthophyllite, amosite, and crocidolite. Red cell mobility was measured by capillary migration on Whatman paper strips and by electrophoresis. All dusts tested significantly decreased the erythrocyte surface electric charge as compared to control samples that were free of dust.Pretreatment of quartz dust with Polyvinylpyridine-N-Oxide restored the electronegativity of erythrocytes. The results obtained provide support for the cytotoxic effect of quartz and asbestos on the external cell membrane.     

黄根抗石棉尘肺泡巨噬细胞毒性的研究

应用体外培养和扫描电镜技术探讨黄根抗石棉粉尘的细胞毒作用及主要作用方式。结果表明:黄根对兔肺泡巨噬细胞(PAM)未显示明显毒性;经黄根孵育过的PAM再与石棉粉尘作用时,(?)程度明显减轻,培养液中LDH活性仅是直接与石棉尘作用组的51.68％。提示黄根能在一定程度上增强PAM抗石棉尘毒性的能力,进而减轻了PAM自身的损伤。本实验为石棉肺的预防性给药提供了参考。