Rossiter C E, Chase J R
Joint European Medical Research Board, Beaconsfield, Buckinghamshire, U.K.
Ann Occup Hyg. 1995 Oct;39(5):759-69. doi: 10.1016/0003-4878(95)00054-i.
Five inhalation studies of synthetic vitreous fibres have recently investigated experimental tumorigenic responses to four different refractory ceramic fibres (RCF), two fibre glasses, one stone (rock) wool and one slag wool. Except for one RCF, the source materials were typical commercial products. Three studies included positive control groups exposed to chrysotile or crocidolite asbestos. The studies were conducted using state-of-the-art technologies for fibre size separation, fibre lofting and nose-only inhalation exposure. The target average fibre size was 20 microns long by 1 micron diameter. Hamsters exposed to a kaolin RCF yielded a mesothelioma rate of 38%, but no lung cancers. There were no tumours among the chrysotile-exposed hamsters. At the highest dose of 30 mg m-3 in rat studies, the commercial RCF all produced significant numbers of lung tumours, and some mesotheliomas. The fourth RCF, which had been heat-treated to simulate an after-service fibre, did not produce a significant excess of lung cancers, but did produce one mesothelioma. A rat multi-dose experiment with three lower doses of the kaolin RCF yielded one mesothelioma among 379 rats, but no excess of lung tumours. The overall dose-response relation for lung cancer did not appear to be linear, consistent with the possibility of a threshold close to the Maximum Tolerated Dose. No insulation wool (glass, stone or slag) exposure group had a lung tumour rate that differed statistically significantly from the tumour rate for the respective concurrent control groups, sham-exposed to filtered air. There was no significant difference in the total tumour rates between the four insulation wool groups and the control animals, and no significant dose-response relation above the respective sham-exposed control tumour rates. The total lung tumour rates for rats in both chrysotile and crocidolite exposure groups were significantly raised. One animal in each asbestos-exposed group developed a mesothelioma, whereas no air control or insulation wool-exposed animal did so.
近期有五项关于合成玻璃纤维的吸入研究，调查了对四种不同的难熔陶瓷纤维（RCF）、两种玻璃纤维、一种岩棉和一种矿渣棉的实验致瘤反应。除了一种RCF外，原料均为典型的商业产品。三项研究包括暴露于温石棉或青石棉的阳性对照组。这些研究采用了最先进的技术进行纤维尺寸分离、纤维蓬松处理和仅经鼻吸入暴露。目标平均纤维尺寸为长20微米、直径1微米。暴露于高岭土RCF的仓鼠间皮瘤发生率为38%，但未发生肺癌。暴露于温石棉的仓鼠未出现肿瘤。在大鼠研究中，最高剂量为30 mg/m³时，所有商业RCF均产生了大量肺肿瘤，还有一些间皮瘤。第四种经过热处理以模拟使用后纤维的RCF未产生显著过量的肺癌，但确实产生了一例间皮瘤。一项对三种较低剂量高岭土RCF的大鼠多剂量实验中，379只大鼠中有一例间皮瘤，但未出现过量肺肿瘤。肺癌的总体剂量反应关系似乎不是线性的，这与接近最大耐受剂量时存在阈值的可能性一致。没有绝缘棉（玻璃、石棉或矿渣）暴露组的肺肿瘤发生率与各自同时期暴露于过滤空气的假暴露对照组的肿瘤发生率有统计学显著差异。四个绝缘棉组与对照动物的总肿瘤发生率没有显著差异，且在各自假暴露对照肿瘤发生率之上没有显著的剂量反应关系。温石棉和青石棉暴露组大鼠的总肺肿瘤发生率均显著升高。每个石棉暴露组中有一只动物发生了间皮瘤，而空气对照组或绝缘棉暴露组的动物均未发生。
