[The in vitro release of hydroxyl radicals from dust containing fluoro-edenite fibers identified in the volcanic rocks of Biancavilla (eastern Sicily)].
BACKGROUND
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.


OBJECTIVE
To investigate the ability of the fluoro-edenite fibres present in mineral dusts and house plaster to release hydroxyl radicals in vitro.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Rapisarda
V
V
Clinica di Medicina del Lavoro, Università degli Studi di Ancona, Polo didattico-scientifico Aragosta, via Tronto 10/a, 60020 Torrette di Ancona, AN. nandorapisarda@libero.it
Amati
Monica
M
Coloccini
Sabrina
S
Bolognini
Lucia
L
Gobbi
L
L
Duscio
Domenica
D
D017638:Asbestos, Crocidolite / Q000737:chemistry; D001205:Ascorbic Acid / Q000494:pharmacology; D003252:Construction Materials / Q000009:adverse effects* / Q000032:analysis; D003676:Deferoxamine / Q000494:pharmacology; D003855:Deoxyribose / Q000032:analysis; D004391:Dust / Q000032:analysis*; D005459:Fluorides / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D017665:Hydroxyl Radical / Q000032:analysis*; D066298:In Vitro Techniques; D007501:Iron; D007502:Iron Chelating Agents / Q000494:pharmacology; D008654:Mesothelioma / Q000453:epidemiology / Q000209:etiology; D019016:Mineral Fibers / Q000009:adverse effects; D008903:Minerals / Q000737:chemistry*; D010997:Pleural Neoplasms / Q000453:epidemiology / Q000209:etiology; D012802:Sicily / Q000453:epidemiology; D012987:Soil / Q000032:analysis*; D013890:Thiourea / Q000031:analogs & derivatives* / Q000494:pharmacology; D018707:Volcanic Eruptions
D004391:Dust; D016166:Free Radical Scavengers; D007502:Iron Chelating Agents; D019016:Mineral Fibers; D008903:Minerals; D012987:Soil; D017638:Asbestos, Crocidolite; D017665:Hydroxyl Radical; D003855:Deoxyribose; C038983:1,3-dimethylthiourea; D006861:Hydrogen Peroxide; D007501:Iron; D013890:Thiourea; D003676:Deferoxamine; D001205:Ascorbic Acid; D005459:Fluorides