Document zb517z6DbzDmkRna42RaGBBR3

LT.yaiene Qigest May, 1^68 _ manta1. Asbestosis. Studies on the Progressiveness of :he Pulmonary Fibrosis Caused rTT-hrvsotile Dust. P. Cross and R. T. P. deTrevllle. Arch. Environmental Health _1_5. 638^TiNov. l*? /1. (Reprints available from Industrial Hygiene F variation. -4-100 Fifth Avenue, i'ttsburgh. Pennsylvania 15213. ) ; {Ji hamsters, and guinea pigs were given various lung dust burdens of chrysotlle asbestos; Tone, by inhalation and others, by intratracheal injection. For the rat, chrysotiie has about same order of pathogenicity as quartz dust, insofar as a single intratracheal injection of be.'."-eri - and ? mg of either dust util produce minimal lesions m rats. Evidence for the no.npro ls siveness of chrysot-.ie asbestosis :r. rats consists of the observations that the minimal aa-estotic lesion is limited to the '.vail of the respiratory bronchiole and of the adjoining alveolar i-cts and does not extend into adjoining normal alveoli and that the minimal asbestotic lesions '-eal by becoming collagenized and hypocellular. In hamsters, the asbestotic lesions are not -^limited. They are diffuse, cellular, and do not collagenise. These lesions are therefore --ogressive. The early chrysotiie asbestotic lesion In guinea pigs resembles that of rats. The srogresslveness of the chrysotiie asbestotic lesion in hamsters is ascribed to a less effective -ul/nonary clearance mechanism and to a greater reactivity of the pulmonary tissue than exist \ rats. The efficiency of the clearance mechanism of man approximates more that of the rat r.an that of the hamster. Man's lung tissue reactivity also more closely resembles that of the -at. being characterized by the ability to heal. -- Cond. from author's summary. Kbastos Bodies in Routine Necropsies on Tyneside, T. Ashcroft, tdt. Med."j. j., 614-617 (March 9,' 1968). Smears prepared from an incision In the base of the right lung in a series of 311 routine necropsies in patients over 15 years of age were examined microscopically for asbestos bodies. In cases giving a positive smear 6p,-histological sections of lung were also examined. The occupational history was obtained by questionnaire or by interviewing the relatives. Asbestos bodies were found in 20. 3*4 of cases (25.5*4 of 196 males; 11. 3*4 of 115 females). Histological sections of lung revealed bodies in less than half of the cases examined. Minimal asbestosis was found In patients dying from gastrointestinal or lung carcinoma. Positive smears were more common in patients from urban areas, '.Vhere information was available, definite, or orobably occupational exposure of asbestos occurred in over half the cases with positive smears. significantly higher Incidence of bodies was found in histological sections of lung from 23 :ises of diffuse mesothelioma of pleura or peritoneum than in the serieB ot routine case3. -- J. Am. Med. Assn. References ic Reviews Airborne Fibrous Class Particles. Chest Roentgenograms of Persons With Prolonged Exposure. 3. '.V. 7'.'right. Arch. Environmental Health _l_o, 175-131 (Feb., 1?68). Tl-.e effect, as revealed in the chest roentgenogram, of ten to twenty-five years of exposure r. an environment containing airborne particles of fibrous glass has been studied. No unusual cittern of radiologic densities was observed. The frequency of various radiologic appearances .-.r.own to occur in the general population was no higher In those with greatest exposure than in those with the least. Two references are given. -- Author's summary The Evaluation of the Performance of an Electrostatic Precipitator "sing a Pollak-N'olan "ucleus Counter. C. McCreevy. Atmospheric Environ, m 37-35 (March, 1367). `'hen an electrostatic precipitator was employed to sample a heterogeneous aerosol, there was a lias in favor of both small ar.d large particles. The results were independent of the original charged condition of the aerosol entering the precipitator and of the concentration of the nuclei it. the aerosol. There are 16 references. -- Public Health Eng. Absts. "told Method for Evaluating Dust Collectors. 0. S'.ancor.i. ' :c. ?.sv, .Ottawa- 1 \ II). i-3, 11 - 00 (1 J671. ` me .eilieir.i particle sice -i\-a a.vre :s suggested far the rapid determ.inacior. o: dust tlency a: lew c-.sc and g-:c ac cur icy. Two comparisons with conventional ole tsehr.icue or. l large e.e :tro static precisltator are reported.-- Author s aost.