Document qk2Q10Jemr5nVjbYRdzOkwDj

- be-responsible ior the decreased \ ' acterial pneumonia. In recov. 1 ctions, the production of I ^,7!X .it._-dies and interferon m.iy i^>>portant protective agent than .i,'i'ivChe interferon content of mouse $$$#tenza virus infection has been ; *' ] ^ii'ow closely the peak of virus ntibody was not detected in lung. until at least a week later.* ;hs occurred within two to five viral infection and NO. exposure lies reported here, the production on may be influenced by N0;,, anisms involved in the reduced ' NO.-cxposcd squirrel monkeys . and viral infection are now irri gation. ! ' / *u aupported by fund* provided by . Air Pollution Control Administration, of HetKh. Education, and Wcllart, ct PH-86-67-30. nine the research reported here, Ox" adhered to Principlei of Laboratory a* established by the National Society ' Research. t I I nitrogen dioxide: II. Effect on histn>1 lung tissue. Arch Environ Health 1969. H( ). nry MC: Chronic toxicity ot iflcct on resistance to bacterial :h Environ Health 17:860.865. 1968. mo A. Ehrlich Ti. Petrold R: Effect at toke oo resistance to respiratory inter n-iron Health 16:385-391, 1968. ker t, Carpenter RD. Luchsinger PC, .. alveolar macrophage viability. Arch ,h 18:756-759. 1969. A, Hitchock C: Role ol interferon in j a virus infectiooa Lancet 2H5&-71, I960, j *d "synthesis" is regarded with Igest that the past century was reality so that we could look at diKciplinox got going. The next lunlly with complexes of things, nent of man.--Hnra FK: How 1970. ( < ir i Asbestos Versus Nonasbestos Fibers UlCramicroscopic Criteria Patti Grots, MD; Jiobert T. P. deTrcville, MD, Sc D; and. Martin N. Halier, Pittsburgh To classify usefully fibrous dusts Inhaled by urban populations, it is sug gested that they be categorized initially as asbestos or nonasbeslos fibers. This would supply Information aufficient lor statistical significance and re duce analytical requirements, saving time and money. The uttramicroscopic criteria of asbestos fibers are ends which have profiles characterized by step-like interruptions up or down from each other, as seen at a magnifica tion Of 20,000 or 25,000 X under the electron microscope, and a surface view (scanning electron microscope at the same magnification) character ized by parallel longitudinal lines that delineate the fibrils. The ultremicroeeopic criteria of nonesbestos fibers viewed at 20,000 or 25,000 X magnifi cation art ends which have uninterrupted linear profiles, and a surface view devoid of longitudinal parallel lines. Fibrous dust particles are ubiquitous.1 Many are of respirable size and can be recovered quantitatively from lungs with ferruginous bodies that develop from some inhaled fibers.2 The finding of ferruginous bodies in the lungs of urban dwellers has been interpreted by some to indicate pollu tion.of community air with asbestos dust.*-4 As an extension of this interpretation, it was predicted that asbestotic pulmonary fibrosis would result in urban dwellers who were inhaling asbestos fibers from the wearing Submitted for public*tion Sept 12. 1969; accepted Kov 13. | From the Department of Ocatpetionel Health, Industrial Hygiene Renenrch Unit, University of I'illNburgh CmluAle School of ISiblir Henlth (Dr. (kmi) nnd tlic Imluxtrinl Hygiene Kounrlntinn of America, Inc. (Dr. dcTrovillc), Pittsburgh. Haller b I fellow of Mellon Institute, Camegie-Molloo University. Reprint request* to Industrial Hygiene Foundation at America. Inc., 6231 Centre Ave, Pittsburgh 16282 iDr. dsTrwviUt). J down of automobile brake-linings and from the weathering of various asbestos-cement products.* It was even suggested that an increase in the prevalence of lung cancer and mesothelioma may be attributable to inhalation of such polluted community air.* The concern aroused by this interpreta tion stimulated an investigation which as certained that ferruginous bodies were not specific indications of the presence of asbes tos fibers, since a number of fibrous dusts other than asbestos could produce structures indistinguishable from asbestos bodies.* This suggested that the presence of pulmo nary ferruginous bodies in urban popula tions is not necessarily on index of atmos pheric pollution with asbestos dusl. It is important to determine if urban populations the world over3-* are exposed to potentially harmful asbestos dust and, if so, to what extent Such determination requires identi fication of the naked fibers and central cores May 1970 Arch Environ Health--Vol 20, May 1970 .( SCF-FA-6314 0(>0 0w32 nth PRODUCED BY FORD