Mechanisms of Asbestos and Nonasbestiform Particles and Fibers in Bronchogenic Carcinoma.
Health Issues Related to Metal and Nonmetallic Mining 1983:123-134
The mechanisms underlying asbestos (1332214) and nonasbestos type particles and fibers in the development of bronchogenic carcinoma were investigated. Methods for long term culture of hamster tracheal epithelium after in-vitro exposure to known amounts of minerals were developed. The cocarcinogenicity of the polycyclic aromatic hydrocarbon (PAH) 3-methylcholanthrene (56495) (3MC) after adsorption on crocidolite asbestos (12001284) (CA), carbon (7440440), kaolin (1332587), and hematite (1317608) was determined. It was theorized that the cocarcinogenicity may be related to either affinity of the dust for 3MC, or its elution into the culture medium. However, the relative amounts of 3MC adsorbed and released from the different particulates was not consistently related to tumorigenic potential. This led to an examination and detailed discussion of the concepts of carcinogenesis and the role of promoters. Events in the cellular transformation involved inhibition of normal differentiation, and induction of ornithine- decarboxylase, the rate limiting enzyme. The increased incorporation of thymidine, basal cell hyperplasia, and the appearance of squamous metaplasia in cultured tracheal cells was mentioned. The importance of interactions between PAH and minerals was considered. The authors conclude that asbestos appears to be noncarcinogenic or only weakly carcinogenic in tracheal epithelium unless combined with complete carcinogens such as PAH or cigarette smoke, and that the effects are similar to those of classical tumor promoters. Compared to the nonasbestos type materials, the asbestos type particles increase activation and retention of PAH, thereby increasing the chances of interaction between PAH and DNA, the transformation target.
NIOSH-Grant; Pulmonary-system-disorders; Carcinogenesis; Carcinogens; In-vitro-study; Lung-cancer; Mineral-dusts; Miners; Occupational-exposure; Respirable-dust; Mineral-dusts; Polycyclic-aromatic-hydrocarbons;
Pathology University of Vermont RM a-151 Medical Alumni Bldg Burlington, VT 05405
1332-21-4; 56-49-5; 12001-28-4; 7440-44-0; 1332-58-7; 1317-60-8;
Book or book chapter;
Wagner-WL; Rom-WN; Merchant-JA;
Asthma and Chronic Obstructive Pulmonary Disease; Disease and Injury; Pulmonary-system-disorders;
Health Issues Related to Metal and Nonmetallic Mining
University of Vermont & St Agric College, Burlington, Vermont