Comparison of primary lung tumor incidences in the rat evaluated by the standard microscopy method and by multiple step sections.

The data presented in this paper have been derived from a carcinogenicity experiment with rats as part of a comprehensive research project focused on experimental studies on the toxicity and carcinogenicity of intratracheally instilled granular dusts [Ernst H, Rittinghausen S, Bartsch W, Creutzenberg O, Dasenbrock C, Görlitz B-D et al. Pulmonary inflammation in rats after intratracheal instillation of quartz, amorphous SiO(2), carbon black, and coal dust and the influence of poly-2-vinylpyridine-N-oxide (PVNO). Exp Toxicol Pathol 2002; 54: 109-26; Ernst H, Kolling A, Bellmann B, Rittinghausen S, Heinrich U, Pott F.

Lung tumor risk estimates from rat studies with not specifically toxic granular dusts.

Since 1985 several carcinogenicity studies have been published about lung tumors in rats after exposure to respirable granular biodurable particles without known significant specific toxicity (abbreviation of this complex definition by the three letters GBP to substitute the former term inert dusts). During this time, the relevance of the carcinogenicity of GBP in rats was questioned, for example, because no lung tumors from GBP were found in hamsters and carcinogenicity in mice was questionable. However, the carcinogenesis and the tumor risk from quartz appear similar in men and rats, and the effects of GBP in rats appear not to differ, on principle, from that of quartz, but at a much higher dose level.

Pulmonary tumor types induced in Wistar rats of the so-called "19-dust study".

The incidences of primary lung tumor types histologically diagnosed in 28 groups of Wistar rats of the so-called "19-dust study" are described, the total study having been already presented by Pott and Roller (Carcinogenicity study with nineteen granular dusts in rats. Eur J Oncol, 2005; 10: 249-81). Each exposed group was repeatedly instilled intratracheally with a suspension of one type and dose of 13 non-mining dusts differing in at least one of the following properties: chemical composition, density, specific surface area, and mean particle size.

Pulmonary inflammation in rats after intratracheal instillation of quartz, amorphous SiO2, carbon black, and coal dust and the influence of poly-2-vinylpyridine-N-oxide (PVNO).

Effects of poly-2-vinylpyridine-N-oxide (PVNO) were investigated in numerous in vivo and in vitro studies published in the nineteen sixties and seventies. These studies showed that PVNO inhibited development of fibrosis from quartz dust and improved lung clearance of quartz after inhalation exposure. Ameliorating effects of PVNO were observed also for pulmonary damage from colloidal SiO2 and organic substances, and the fibrogenic inflammation caused by carrageenan.