Document QX5KaVN86R6ayNo87LBxBg625

R. M. ANDRE, M. D. Su pe r v is o r Me d ic a l Se c t io n W O R K M E N 'S C O M P E N S A T IO N TH E I N D USTR IL C M MI SS I N O F MEDICAL SECTION Co l u mb u s H IO IN RE CLAIM NO. February 18th, 1943. Dr. Eobt. A. Kehoe, University of Cincinnati, College of Medicine, Cincinnati , Ohio. Dear Doctor Kehoe: In accordance with our recent conversation, I am enclosing a copy of the laboratory procedure used by Dr. Davidson's Laboratory, and we would appre ciate your comments on this procedure. I am at the present time working on a proposed list of approved laboratories for the determin ation of quantitative blood and urine leads. I wish to again extend my appreciation for your kind cooperation. . Very truly yours, BA/MMW. Eno. Ben Amoff, M. D., Chief, Occupational Diseases. YS 001S768 NATION `OP LEAD IN BIOLOGIC TI SSUES AND. FHTIDS (METHOD Ow CHOICE)' Myers, Gustafson, aid Throne describe emthods which are based upon Fairhall's volumetric and colorimetric estimations. Determination of Lead in Biologic Material.-- I. Preparation of Samples. . A. Urine: A liter of urine is used whenever possible. The urine must be fresh or preserved, preferably, with, thymol. It is, ..made ammoniac a1 by the addition of 50 c.c. of concentrated ammonium hydroxide and allowed to stand overnight. The lead is carried . down by entrainment in the phosphate.precipitate. Most of the ; supernatant fluid m a y be siphoned, off and t h e 'rest of the sample is filtered through 12.5 cm. No. 40 Whatman filter paper, The - specimen is dried in the oven and is then ready for ashing and 'a extraction. . .- : B. Blood: Whenever possible, 10 c.c. of oxalated blood are measured into a weighed Coors porcelain crucible and dried in oven. Clot may be used. When the specimen ia dry it is . weighed before -ashing to determine dry -weight, 0. Feces: The sample is placed in a weighed Coors porcelain crucible, dried, and weighed before ashing. D. Spinal Fluid: A measured volume is placed in a crucible, weighed and dried in the oven before ashing. . S. `Hair and Hails: Weigh and ash. - F. Tissue: Drv, weigh, and ash. II. Ashing and Extraction. * . The samples are ashed as completely as possible at red heat over a Bunsen flame. .About 1 c.c. of fuming nitric acid . may be-, added to the urine, feces, and blood samples to complete - the ashing. This is not necessary with spinal fluid, hair, nails, and tissue. . . The crucibles are cooled and 7 c.c. of 1 : 2 .hydrochloric acid are added. The acid is ,boiled gently in the crucibles, cooled, and- filtered through 7 .cm. No. 40 Whatman filter paper into a 250 c.c. Pyrex Erlenmeyer flask. The crucibles are washed four or fives times with approximately 5 c.c. of cold distilled water for each washing. The washings are-added to the filtrate and the final volume is about 35 c.c.' ' . The filtrate is, made .just alkaline with approximately 5 c.c. . of 25 per cent sodium hydroxide, then just acid with .1:2 hydroch loric acid and 1 c.c. of acid is added in excess. Methyl orange . is used as an Indicator. The solution Is diluted to about 150 c.c. and hydrogen sulphide' i a pa seed into, the cold solution for thirty minutes. The sample is then .allowed to stand overnight to insure , complete precipitation of lead, sulphide. , The sulphide solution is filtered through 12.5 cm. No. 40 ` Whatman filterpaper. The flasks and filters are washed three times. .About 15 c.c. of distilled water are used for each washing. Fifteen cubic centimeters of hot 1:1 nitric acid are used to dis- , solve the lead sulphide precipitate and this is caught in the precipitation flasks. The filters are washed with hot water un-' til the tptal volume in the flanks in about 50 c.c. This solution is evaporated tq.ybout 5 c .c. and transferred ouantitati velv to /.\.v< a I S O c.c. Pvr ex -beaker. .The total volume of solution and washings" should be about 50 c.c. Three drops of phenolphthaloin are added - and, the sample made just alkaline with 25 per cent sodium hydroxide, just aeis with 10 per cent acetic acid, and 1 c.c. of acid is added in excess. The content? of the beaker are boiled, then 1 c.c. of 1 per cent potassium chromate is added and then heated on the water -bath for one.hour",''then allowed to stand overnight. The chromate ir filtered hot through 7 cm. No. 40 Whatman filter" P|tper, then both beaks'-- and filter are washed three times* each with hot water using about 10 e. c. for each washing. The chromate precipitate is di-solved off the filter paper with 2 c.c. 1:2 hydrochloric acid which is caught in the precipitation beaker. The filter is washed with 40 c.c. of water added in small portions. Five cubic centimeters of 10 per cent potassium, iodide are added to each sample and after three minute? they are titrated with 0.005 N sodium thiosulphate, using starch as an indicator. One cubic centimeter of 0.005 jl sodium thiosulphate equals 0,3451 mg. lead. A microburet used for the titration is graduated in 1/100 c.c. graduations. The 10 per cent potassium iodide solution is made up fresh each time. The sodium thiosulphate solution is made up fresh each time from a stock solution of 0.1 N thiosulphate Example: Calculations and Results. 1.53 c.c. of 0.0049 .normal sodium thiosulphate were used in the titration. 0.34441 x 1.53=0.5269473 mg. of lead per 860 c.c. of urine (original sample). , 475 x 1000=0.6127 mg. of lead per 1000 c.c. of urine. 860 ) ` " According to che Journal of Industrial Hvgiene, 15: No. 5, September, 1933, the, normal volume is 0.017-0.026 mg. of lead per liter. ' -- suiaiAHY o p u r i n a r y o h a n g IN LNAJ p,0ISON1NG The urinary changes in lead poisoning are a ? follows: albumin; granular casts: red cells: abnormal amounts of lead (see above tests); hematoporphvrin. . - SUMMARY OF BLOOD CHANGER IN LEAD POISONING The blood changes in lead poisoning are as follows: low red cell count; low hemoglobin; high blood platelet count; presence of nucleated red cells; changes in the morphology of the red blood cells; basophilia; polychromasia. (For fuller details,, see Hematology of Lead Poisoning in Chapter on Hematology, page 506.) 001S770