Document da9N5jzMgGkVVez7VYKBmDyre

industrial Hygiene Digest 281 Fundamental a of Silicosis Research. K. Thomas. Schweiz. med. Wochscnr. 94. 213-217 (Feb. 15, 1964). The author discusses the conditions which have a bearing on the development, in x. perimental intraperitoneal testa, of the stratified hyaline granuloma which is characteristic of silicosis. Special attention is drawn to the granule size and the surface texture of the powders- the crystalline texture of the SiOr material, on the other hand, is not particularly significant. The recently discovered high-pressure and high-temperature modified materials, called "Coesit" and "Stischowlt" will probably provide further insight into the primary mechanism of the tissue-damaging reaction of the SiOj particle after phagocytosis. These investigations fall within a hitherto neglected sphere of biological chemistry, known as solid-body biology. In this field, the relation of the texture of solid surfaces to certain metabolic reactions is studied. --APCAAbsts. 282 Experimental Trlcalclum Phosphate Crystallosis. H.A. ReUnarm, Thelma Ducanes, and R. Patter. Arch. Environmental Health 10, 33-36 (Jan. 1965), Crystals smaller than 5 microns of triealcium phosphate, a component of some denti frices, entered the intestinal mucosa of rats after Ingestion and their lungs after intracheal injection. Intraperitoneal injection caused local microscopic foreign-body granulomas. The lungs and the gut served as portals of entry for the hematogenous and lymphogenous systemic dispersion of crystals. They were deposited in normal appearing tissues, or caused areas of mild or severe inflammation and granulomas. -- Authors' summary 283 Lung Structure--Relation to Response to Particulate. P.P. Yevich. Arch. Environmental Health 10, 37-43 (Jan. 1965). One of the main anatomical differences between the lung of the dog and rat is In the terminal portions of the bronchial tree. Exposure of dogs and rats for long periods to oil mist and calcined diatomaceous earth revealed that the histopathologic response In the dog was limit*! to accumulation of particulates and macrophages around the respiratory bronchioles; the alveolar spaces of the air sacs were free of any changes. In the rat the histopathologic changes showed accumulation of particulate-laden macrophages in the alveolar spaces and around the blood vessels. Phagocytosis of the particulates by macrophages was seen in both species of animals. Accumulation sites differed between the rat and dog. This probably was due to lack of lymphatics and a long respiratory bronchiole in the terminal portions of the bronchial tree of the rat lung. Bronchoconstriction in the dog may be an important factor for the accumu lation of particulates in this area. That the human lung accumulates particulates around the respiratory bronchioles has been shown by numerous researcHers. -- Author's summary 284 Asbestosis and Lung Cancer. W.J. Williams. Arch. Environmental health 10, 44-45 (Jan. 1965). This report records 52 American cases of asbestosis among whom there were 10 pa***8" with malignant tumors, an incidence similar to that reported in Britain. There are 17 referec<> -- Author's conclusion 285 Lung Function Changes in Talc Pneumoconiosis. M. Kleinfeld, et al. J. Occ. -Nied. 7, 12-17 (Jan. 1969). r Pulmonary function tests were performed in 16 workers who were engaged in the mill*8.' of talc for more than 10 years and had clinical and roentgenographic findings consistent with ts', pneumoconiosis. In 14 of 16 the pneumoconiosis was symptomatic. Dyspnea was the predotn:1''*' symptom. Cough was present but was not consistent. The mean duration of exposure for the ^ group was 20.4 years, with a range of 13.26, and the mean weighted average exposurewas *>3- mppef. The latter exceeds the present threshold of 20 mppcf as recommended by the Americ8 Conference of Governmental Industrial Hvgier.ists. The changes in pulmonary function indicte` that there was an impairment in ventilatory function and diffusion capacity (Olcp) la a sign*' |( fiuhnt number of individuals. The changes in ventilatory function were primarily of a restnC* type, although in some instances an obstructive component was also present, Some correlat*11. was found between Dj.co and clubbing and pulmonary infiltration. The total lung capacity *!<>**' a correlation with clubbing only. There are 11 references. 20. - - Authors' summary