Rapisarda V, Amati Monica, Coloccini Sabrina, Bolognini Lucia, Gobbi L, Duscio Domenica
Clinica di Medicina del Lavoro, Università degli Studi di Ancona, Polo didattico-scientifico Aragosta, via Tronto 10/a, 60020 Torrette di Ancona, AN.
Med Lav. 2003 Mar-Apr;94(2):200-6.
Epidemiological studies revealed an unusually high incidence of malignant pleural mesothelioma in Biancavilla, a town in eastern Sicily located in a volcanic area. In the absence of occupational risk factors connected with asbestos inhalation, a nearby stone quarry, which has long been providing most of the local building materials (e.g. plaster), was suspected to be the source of mineral fibres. These fibres had never been studied before and were identified as fluoro-edenite.
To investigate the ability of the fluoro-edenite fibres present in mineral dusts and house plaster to release hydroxyl radicals in vitro.
After fibre characterisation and the determination of particulate specific surface, the ability of quarry rock dust and house plaster dust to generate hydroxyl radicals was measured in vitro using the deoxyribose degradation assay. Treatment with 1,3-dimethyl-2-thiourea (DMTU), a hydroxyl radical scavenger, or deferoxamine (DFX), an iron chelator, was performed to confirm hydroxyl radical production and study the role of iron. Crocidolite (UICC) was used as positive control.
The rocks were found to contain fibrous amphiboles, identified as fluoro-edenite, which are chemically similar to tremolite. All samples generated hydroxyl radicals, with rocks yielding consistently higher values than plaster. Treatment of the dusts with DMTU or DFX significantly reduced hydroxyl radical production by both samples. The type of biological reactivity observed with these fluoro-edenite fibres resembled that of asbestos fibres.
The hydroxyl radicals generated by asbestos fibres have long been known to mediate inflammatory fibrosis of the lung and DNA damage that may ultimately result in lung carcinoma and mesothelioma.
流行病学研究显示，位于西西里岛东部火山地区的比安卡维拉镇恶性胸膜间皮瘤发病率异常高。在没有与吸入石棉相关的职业风险因素的情况下，附近一个长期以来一直提供大部分当地建筑材料（如石膏）的采石场被怀疑是矿物纤维的来源。这些纤维此前从未被研究过，被鉴定为氟钙闪石。
研究矿物粉尘和房屋石膏中存在的氟钙闪石纤维在体外释放羟基自由基的能力。
在对纤维进行表征并测定颗粒比表面积后，使用脱氧核糖降解试验在体外测量采石场岩石粉尘和房屋石膏粉尘产生羟基自由基的能力。用羟基自由基清除剂1,3 - 二甲基 - 2 - 硫脲（DMTU）或铁螯合剂去铁胺（DFX）进行处理，以确认羟基自由基的产生并研究铁的作用。将青石棉（国际癌症研究机构）用作阳性对照。
发现这些岩石含有纤维状闪石，鉴定为氟钙闪石，其化学性质与透闪石相似。所有样品均产生羟基自由基，岩石产生的值始终高于石膏。用DMTU或DFX处理粉尘显著降低了两个样品的羟基自由基产生量。观察到的这些氟钙闪石纤维的生物反应类型与石棉纤维相似。
长期以来已知石棉纤维产生的羟基自由基可介导肺部炎症性纤维化和DNA损伤，最终可能导致肺癌和间皮瘤。
