Linkage Between Silica And Lung Cancer

Crystalline silica (quartz) is a mineral found in many types of rocks, granite, mineral deposits, and sand. Silica is a well-recognized health hazard for workers engaged in mining, construction, sandblasting, farming, and other occupations. Environmental exposure to aerosolized fine silica is also a major public health issue. Although silica is now considered as a human carcinogen, the molecular mechanisms involved in silica-induced carcinogenesis remain to be answered, because evidence for carcinogenicity in humans and animals is still debated. Human epidemiologic studies have not conclusively documented evidence or a dose-response relationship regarding the role of silica as a potential carcinogen in many exposed population studies. Furthermore, animal exposure studies to silica are controversial, because silica shows species differences in carcinogenicity. In the rat, a single intratracheal instillation of silica induces lung tumors, i.e., mostly of adenocarcinomas associated with silicotic fibrosis. In mice and hamsters, on the other hand, similar exposure to silica does not produce characteristic fibrotic lesions or tumors.86 However, silica can interact with human and animal pulmonary cells in vitro and in vivo to induce carcinogenesis through several mechanisms directly involving ROS generation, DNA damage, apoptosis, signal transduction, induction of oncogenes, and activation of transcription factors. Obviously, a sustained induction and activation of these silica-induced cellular responses may promote carcinogenesis.

A Disquistion On The Evils Of Using Tobacco

A Disquistion On The Evils Of Using Tobacco

Among the evils which a vitiated appetite has fastened upon mankind, those that arise from the use of Tobacco hold a prominent place, and call loudly for reform. We pity the poor Chinese, who stupifies body and mind with opium, and the wretched Hindoo, who is under a similar slavery to his favorite plant, the Betel but we present the humiliating spectacle of an enlightened and christian nation, wasting annually more than twenty-five millions of dollars, and destroying the health and the lives of thousands, by a practice not at all less degrading than that of the Chinese or Hindoo.

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