Retained particle burden in the lungs of monkeys after chronic quartz dust exposure.

A chronic exposure study was designed simulating conditions of modern tunneling construction in which a hyperbaric atmosphere was combined with shotscrete lining methods producing a silicate aerosol at high relative humidity. Monkeys were exposed to either a DQ12 quartz dust concentration of 10 mg/m3 or a hyperbaric atmosphere at 2500 hPa or a combination of both over 26 months. All quartz-exposed monkeys developed silicosis. In this part of the study the retained mass of quartz dust was determined in the lungs using an O2 plasma ashing technique. Quartz concentrations of 7.05 ± 2.78 mg/g and 11.14 ± 3.29 mg/g dry lung tissue was found in the quartz-exposed group and in the quartz-exposed group at hyperbaria, respectively. Although the quartz concentration was rather homogeneous in a given lung, differences in the quartz concentration between individual animals indicated a sustained variation in deposition in the lungs and/or clearance from the lungs

Proliferative and nonproliferative lesions of the rat and mouse respiratory tract

The INHAND Project (International Harmonization of and Diagnostic Criteria for Lesions in Rats and Mice) is a joint initiative of the Societies of Toxicologic Pathology from Europe (ESTP). Great Britain (BSTP). Japan (JSPT) and North America (STP) to develop an internationally-accepted nomenclature for proliferative and non-proliferative lesions in laboratory animals. The purpose of this publication is to provide a standardized nomenclature for classifying microscopic lesions observed in the respiratory tract of laboratory rats and mice, with color photomicrographs illustrating examples of some lesions. The standardized nomenclature presented in this document is also available electronically on the internet (http.//www gorem org/) Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous developmental and aging lesions as well as lesions induced by exposure to test materials. A widely accepted and utilized international harmonization of nomenclature for respiratory tract lesions in laboratory animals will decrease confusion among regulatory and scientific research organizations in different countries and provide a common language to increase and enrich international exchanges of information among toxicologists and pathologists