diation effect oceurs, but they also reflect changes that are isiduced by i@ radiation. The data have been gradually accumulated and subsequent evaluatiog of e course of the disease has been considered in the light of these findings. ese studies go far beyond the usual routine observations commonly sade on tients treated with I 31, The ultimate value of the data is not full own because the long term effects of ti3l are only recently coming tc ght. Our laboratory represents one of 19 centers included in the Public alth follow-up study of J/31 treated patients. Our detailed data on proximately 175 of these patients, studied under this contract, have oven to be the most thorough in this national study. The kinetics off the 31 in these treatment petients, along with the collateral observatiore @ now serv: vior of r131. as the basis for attempting to define the patterns of be- It ig the hope of those in charge of the national project at, having established kinetic patterns from the data on our patients on fragmenta of data from other less completely studied patients fron other iters can be analyzed and the missing data eatimated for thoss patients the use of computors, The reasons for the variations in the therapelitic tcome may thus be learned in a large number of patients now being folkowed. : responsible investigator of this contract has been appointed Chairman of > Steering Committee concerned with the analysis of the clinical data] that ‘e now been assembled from the 19 centers. It should be admitted tha th of the data that have been acquired under this grant are not fully lerstood by us, but with the collaboration of others more knowledgeable the study of kinetica and the use of patients from other centers, more uld be learned. We continue to carry out a detailed study on selected ‘lents when: 1) an appropriate patient is to be treated, 2) when he is lable for intmeive study, and 3) when the personnel working under itract have a sufficient block of consecutive days to complete the stady that patient. , Synthesis in Radiated and Stimulated Rat Thyroids Gradually, as the project has progressed, emphasis has shifted somewhat e from the purely physiologic toward the morphologic changes caused |! 1 radiation. The Large bizarre nuclear forms originally found and cribed (1,¢) at the beginning of this project have received increasing ention. The production of the odd nuclear forms in animals after ony 12 doses of 1131 followed by a stimulus of thiouracil has been re- ted(1,2) from this project. The finding of excessively large amounts DNA as demonstrated(3) by Feulgen staining and quantitative microspedtrotometry in nuclei of thyroid cells of animals was reviewed in detail complete review submitted last year. A manuscrppt entitled "The Acute and Long Term Effects of Var3us Hoses Radioiodine on the Thyroid of the Rat as Demonstrated by Mitotic Activity ng Tritiated Thymidine"(4) wes apperJed as a separate manuscript with our orehensive report one year ago. That mar ‘ccript was sent to Endoc polos publication. Some relatively minor editirial suggestions were made editor. With the lapse of time, and rer » ideration of the manuacript, 3eemed the paper could be improved upon, .-. only by making some suggested x3 revisions, but by redesigning the presentation with some change in 1asis. In that study tritiated thymidine was used in rats to show ratlio-~ graphically which cells were forming DNA in preparation for mitosis.