Document 6RgD9Mn7NzYn82O7naGLD5oR1

Ba l t imo r e Cit y Ho s p it a l s Fr e d e r ic G. Hu b b a r d d ir ec t o r 4940 EASTERN AVENUE BALTIMORE, MARYLAND 21224 October 12, 1971 IN REPLY REFER TO: Dr. Robert A. Kehoe Professor Emeritus of Occupational Medicine Kettering Laboratory Department of Environmental Health University of Cincinnati Eden and Bethesda Avenues Cincinnati, Ohio 45219 o Dear Dr. Kehoe.- - It was indeed a pleasure and a privilege for me to visit the Kettering Labora tory last week. 1 do want to thank you for your great kindness in showing me about the laboratory during the late afternoon. I shall certainly take your advice about certain respiratory exposure data relative to lead. We did not get a chance to discuss the necropsy data which you are now collecting. I am wondering whether you are finding any signifi cant differences from the data reported by Tipton and Schroeder and by Mossman and Barry. There is a great deal of scatter in the data reported by them. I mentioned briefly during my discussions with the students and staff after the lecture our recent experiences with the determination of total porphyrin in blood. It seems to me that this has great potential, particularly in the practical medical sur veillance of groups such as children and occupationally-exposed workers in whom it might well replace the urinary ALA measurement. While the measurement of porphyrin in blood does not have the apparent specificity for lead effect that the measurement of ALA in urine has, it has some practical advantages. The variations encountered in urinary collections would be obviated. The determination of total porphyrin in blood can be made either by fluorescence or by spectrophotometry. In either case, analysis is less time consuming than the analysis of urine. On the other hand, if does not appear that the total porphyrin in blood is stable for more than a few hours. I think that the measurement of total porphyrin in bloodmay also have some biologic significance beyond its practical usefulness. I am at present trying to work out the interrelationship between total blood porphyrin and blood lead concentrations. I would very much like to learn your reaction to these observations. jx. R. A. Kehoe Oct. 12, 1971 Again, it was a great pleasure to have a chance to meet with you and I want to thank you for your generous hospitality. Yours sincerely. JJC:ov i KE 0020210