Document 2q5Q6yXKrLoBqMkpqxRK61O57

FILE NAME: US Gypsum (USG) DATE: May 5, 1937 DOC#: USG026 DOCUMENT DESCRIPTION: 1937 First progress report on asbestosis experiments. First Progress Report on Asbestosis Experiments at the Saransc Laboratory. Kay 5, 1937. To furnish a better understanding of the disease, asbestosis, and to provide standards as a basis for its diagnosis by x-ray films, a group c animal experiments has now been started. It is expected that anatomical -changes will be produced in the lungs of animals inhaling fibrous asbestos which will cast shadows on an x-ray film comparable to those seen in human beings. Since the animals can be killed as seems advisable it will be possible to compare the anatomic changes in their lungs with the shadows seen in the films. To make certain whether the fibrosis in the lung is due to the chemical composition of asbestosis or whether it is the result of a mild irrita tion in the walls of the air spaces resulting from the action of a fibrous foreign body (L.e. its physical structure) injection experiments are in progress. If no fibrosis results from accumulations of asbestos in other organs it may probably be assumed that chemical stimulation of the tissues is not responsible for the pulmonary fibrosis. As a further check on the physical vs. the chemical hypothesis, the action of ground serpentine is being compared with that of chrysotile. Since they both have the same chemical composition the comparison should be instructive whatever the result. To check the effect of mere fibrous structure, a search for other fibrous minerals was made. Hone other than those classified as asbestos could be discovered which had the same structural composition, -owever, because of our interest in the action of gypsum, a sample of satin spar (fibrous) and also one of soda tremolite were selected, for comparative testing. Finally, the action of various members of the asbestos group, amphibole, amesite, crocidolite and anthophyllite are all being compared with that of chrysotile. It is too early to report more than the fact that the experiments have been started. Fo r the inhalation of chrysotile, a dustfurnished by h r . Fisher from a plant at Kanville, N.J. is bein2 employed. As it YcL 5 i'n0 dust was not sufficiently fine for experiments of this type and ~e were forced to regrind i* in a ball mill. Considerable time was spent in experimenting with a proper type of mill for the pur cos e This di.fficulty was overcome and inhalation was be?un on .'aren *-.. In the dusting room we placed 80 guinea pigs, 20 rats, S rabbits and 3 cats, hore of the latter will be procured as they become available. A dust concentration of approximately 17$ million particles cubic foot of air is no1;? being maintained. This may later changed. Over ?CfJ of th? particles are less than 5 microns diameter. Since significant results cannot be expected to develop until exposures have been continued for from 1 to 2 v* o--a r*wc there can be little to report before the expiration of that t i m e . The various injection experiments are further advanced a1th 0 U 2 h it is too early to report any results. For this purpose al 1 have been analysed chemically and petrographically .* They ere then ground ana fractiona.tea by allutriation. Only parti cl 5! 1 o ? microns in diameter were used. Their composition was asain neckea by tne same methods of analysis. The various tests are adulated for your information. et- O et" Chrvsotile ('Thetford') a. Intravenous Injections. Have proved difficult. 7 rabbits have died, apparently from mechanical effects, without receiving significant Quantities o*" the dust. Further attempts are in o-o^e^s o. Intraperitoneal Injections - 5 guinea pigs, larch 31, 1937 One killed after one month. No gross fiorosis. Amphibole a * Intravenous Injection. L rabbits still in progress. Have each received 11 doses totalling G-55 grams. Mo fatalities'. b* Intraperitoneal Injection. 5 suinea Digs. Feb. 5, 1937 " ` ~ 2 killed after 12 and 30 days respectively. Dust plaques without gross fibrosis. Amesit e d Intravenous Injection. L rabbits still in progress, Have each received 11 dose s totalling 0.55 grams. No fatalities. b Intraoeritoneal Injection. 5 guinea pigs on Feb. 5 > 1937 2 died of infection. 1 killed after 1 month, no fibrosis. '.lost of the dust absorbed; - 3- Crocldolite a. intravenous Injection. 4- rabbits-have each received full dose of one gram in '20 injections. None killed. :-:-b.,~--Intraperitoneal -Injection." 7 guinea pigs/ 2 died of infection. . -, . 1 killed after 1 month. Pigmented dust plaques without fibrosis." Anthophvllite a. Intravenous Injection. 4- rabbits have each received fuj.1 dose of 1 gram in 20 injections. 2 killed after 3 1/2 to 6 months respectively. No evidence of fibrosis in the lungs, spleen, liver or bone marrow. b. Intraperitoneal Injection. 5 guinea pigs. 3 killed after 1, L and 8 months respectively. Disappearing reaction with gross evidence of fibrosis. Serpentine a. Intravenous Injection. L rabbits have each received full dose of 1 gram in 20 injections.. All alive and well. b. Intraperitoneal Injection. 5 guinea pigs. 2 killed after 1 and L months respectively. Soft pigmented dust plaques without fibrosis. Fibrous C-vpsum - Satin Spar a. Intravenous Injection. L rabbits have each received 11 of 20 injections, or a total of 0.55 g r a m s ^ ^ N o " fatalities. '-iV '" r' b. Intraperitoneal Injections - not made. Soca Trenolite ... --- -- a. Intravenous Injection. L rabbits have each reos i^ed total dose of 1 gram.'in 20 injections. All alive and well. b. Intraperitoneal Injection. 5 guinea pigs. plaque s wi ihout n c r o s i s None of tnese early results is regarded as significant and no con elusions vrill be d r a m until the observations have been continued for at least one year. It is not+* yet+ /c-lT er \ ar. r'* twrVh eritrVh ea rt +t*1h-1ea CliXvi with intravenous injections of chrysotile are merely a natter of technique or whether this substance is essentially toxic, V.Te are attempting to discover the cause.