Document rxZR1aB48MxYJKoJaMg662DVJ

Industrial Hygiene Digest April, 191 carborundum [or sanding in the shoe industry; and slate or chalk (or stone-dusting io cc mines. Quarts sands hare been prohibited since 1938 in grinding ol glass, and exposur has beeu regulated. The higher cost of artificial abrasives in the glass and ceramic iet tries is offset by higher working speed. -- Cond. from Bull. Hjrg 503 Respiratory Symptoms and Pulmonary Disability in an Industrial Town, Survey of a Random Sample of the Population. L I. T. Higgins',' P. O. Oldham, A. L. Cochrane, andj. C. Gilson. Brit. Med. J. Z\ 904-910 (Oct. 20, 1956). In 1954 the Pneumoconiosis Research Unit of the Medical Research Council carried out a survey of the male population aged 55-64 of Leigh in Lancashire, iu order to compare the prevalence of respiratory symptoms and disability in miners with (hat found in men who had worked only in other occupations. The random sample consisted of 135 miners and ex-miners and 85 non-miners. Pneumoconiosis was found iu 23% of the miners and ex-miners. Chronic bronchitis was found in 10.7% of the non-miners, in 26. 7% of the miners without pneumoconiosis, and In 12.9% of the miners with evident of pneumoconiosis. Some of the conclusions arm (1) miners and ex-miners had signifi cantly more chronic bronchitis, a lower ventilatory capacity, and more respiratory symptoms .than men who bad never worked in mines; (2) miners without pneumoconiosis were on the average more disabled than those with early simple pneumoconiosis; and (3} the differences between miners and non.miners could not be ascribed to differences in social class or smoking habits, and in the miners there was no obvious relationship between length of exposure to dust and bronchitis. -- Cond. from BuU. Hjrg. 504 The influence of the Shape of Dust Particles on the Rate of Phagocytosis In Vitro. A. Lengerova, V. J. Leoger, M, Etalova, R. Tuscany, and M. Voliova, Brit. J. Ind. Med. 14, 43-46 (Jan. 1957). The rate of phagocytosis of two shapes of dust particles--"long" and * round" -- was studied in an investigation in vitro In cultures of macrophages from the spleen of chicken embryos. The round particles were phagocytoeed preferentially. This result is discussed from the standpoint ol existing theories of phagocytosis as well as from - that of the relation of the rate of phagocytosis and the harmfulness of different kinds of dusts. -- Authors' summary 505 The Prevalence of Tuberculosis at Necropsy In Progressive Massive Fibrosis of Goatwork* D. Rivers, W. R. L. James, D. G. Davies, and S. Thomson. Brit. J. Ind. Med. 14. 39-42 (Jan. 1957). v--w One hundred hltf-ttseecamvf coalworkcrs* pneumoconiosis were examined at necropsy (or the presence of tubercle bacilli both by culture and by animal inoculation. The series contained 118 cases of progressive massive fibrosis which were Ihe special object of this study. Tubercle bacilli were isolated from 41 cases (35%) of massive fibrosis, and In 31 (28%) of these naked-eye or histological evidence of tuberculosis was recognized patho logically. The pathological observations, therefore, correlated well with the bacteriologies results. There Is a marked difference between the prevalence of tuberculous infection found in a post-mortem series and that found in life in cases of progressive massive fibrosis. During life the observed prevalence is only 1.1%, The authors found tubercle bacilli in the bronchi at necropsy, in 28%. Thus open tuberculosis is, in most cases,, a late complication of massive fibrosis. Whether tuberculous infection occurs early or late cannot be deduced from this study. -- Authors' summary 506 Pulmonary Tumors In Mice Exposed to Asbestos Dost. K, M. Lynch, T. A. Melver, and J. R, Cain. Arch. ind. Health 15. ^07-214 (Mar. 1957). Mice of a selected strain (AC Pj) were exposed to a dusty atmosphere containing asbestos floats of a type.used by others experimentally, at 150 to 500 million particles per cubic foot. The largest single'experimental group consisted of 127 animals killed at 19 months after exposure for 17 months. This group was compared with 222 control animals. Primary lung tumors were demonstrated microscopically In 46% of the duated mice and In 18. ______________________