1 . . . 1 . . 40 WA UR by NUTY. EN !!, WWW C * . JAM . . * Tos . the O . INN , 1 .. . in UNCLASSIFIED ORNL 2TM . N '. 4 ** i *** . . . .. . : . - . . . . -. , Y V 31 . -- . sa- ARS 419 is. . GRAU & 419 Metrteha International Congress of Internal Medicine. Hovember 23-28, 1966 Dumou Aini, Argentina. Drie OCT 5 1964 MASTER Cytogenetic effects of radiation in me. Michael A Bander Blology Division, Oak Ridge National laboratory, Oak Ridge, Tennessee LEGAL NOTICE - Two roport me popared M ount of Coronment sponsored wort. Meither the United mum, mor the Countnehom, sor may person mun on b all of the Counslon: A. Wahes my usranty or repromulou, expressed or implied, mu respect to the accu. racy, complement, or wenu ole maternion commune room, or that we of ray taler nation, appunto, method, or procon discloned In we report may not latring Minatoly od rhai or B. As my liabilities with impct to the wo of, or for dumme rondre Irun the neolwy Wormattan, omaritu, method, or procum daclound in the report. As www to the webero, "pornoa ating on haualt of the Commission" lekciudeo my m. Wayne or inactor of the Commisslon, or employs of much contractor, to the entral dat nel oploymor cmiractor of the Counselor, or employme of much contractor round, dorominas, or provides acco. bo, may haformation Numaat ho na maployment or coormet with the connoston, or die employment me te contractor. Basearch sponsored by the U. S. Atomio Mero commission under contrast with the Vodon Carbide Corporation. UR Extensive studies have been made of the effects of radiation on the chromosome of buwan somatic cells. Such studies are important for two reasons: They provide us vith direct evidence on which to base stimates of human radiosensitivity, and they enable us to we chromosomal aberration production as a "biological dosimeter" in cases of human exposure. Cell systems used for such studies include tiera cultures of various organs, such as skan or kidneys bone marrow cells, and peripheral leukocytes. In order to yield quantitative Information the cells mint be studies in their first post-irradiation division; tissue cultures are thus muitable only for in vitro experiments, while bone marrow and loukocytes are suitable for AnalyB16 of aberrations induced by 10 riro irradiations. Because peripheral blood 18 easily obtainable, and because the leukocytes are in a uniformly radiosensitive-stage, this material has been used extensively. A large number of in vitro speriments provide us with a wealth of background Information about the Induction of chromosomal aberrations in human cells. In general, this work has shown that human chromovonen behave like those of the extensively studied non-tuman materiás. Imok of suitable material bas alloved only a few quantitative studime ar mama cell. Irradlated vivo, but these have confirmed the 12 mtro ronto. The chromosomal aberrations seen inolude single-break deletions, and multiple- break aberrations, the most important of wich are the ring and the dicentric ahromosomes, cach lavolving two brako. Blaglo-break deletione loorene approximately as a linear function of dome, and two-break aberrations Inorinne approximately as the square of love, when acute donet of X or y mwys are nivea. When high water radiations mon a nosion soutrons are used or when the dove la delivered over a long period of time, bowever, multiple. broad aborration produotion approximate a limang hanation of done. . . .. In order to provide useful material for quantitative makurtunt of in vivo aberration yield, a single dose must be delivered in a relatively short time over the entire body. These requirements are rarely met in therapeutic Irradiations; most studies have been restricted to cases of accidental irradiation. People exposed in throc nuclear criticality accidents and in ona y lay accident have been studied. The results agree with thuse of perullal in vitro blesd exposures. The coefficients of human chromosome aberration induction are 1 x 100% deletions per cell per rad and 0.5 * 10-5 rings and dicentrics per cell per rada por X and y rays. Those for fission spectrum neutrons are 45 x 100% deletiono per cell. per rad and 5.5 x 10 rings and dicentrico por cell per red. Long-term studies of those and other cases have determined the time-course of aberration loss, and established that some aberrations persist for at least twenty years. They have also shown that the presence of such chromosomal aberrations does not generally lead to any clinical manifestations. ETTEN WY .... 1 4 :19 M . *'.. . L LY . DATE FILMED 11/ 30 /64 2 TUUL.. ut > .1. - Lite SA KWA - LEGAL NOTICE – This report was prepared as an account of Government sponsored work. Neither the United States, nor the Commission, nor any person acting on behalf of the Commission: A. Makes any warranty or representation, expressed or implied, with respect to the accu. racy, completeness, or usefulness of the information contained in this report, or that the use of ary information, apparatus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or process disclosed in this report. As used in the above, "pe 'son acting on behalf of the Commission" includes any em- ployee or contractor of the Commission, or employee of such contractor, to the extent that such employee or contractor of the Commission, or employee of such contractor prepares, disseminates, or provides access to, any information pursuant to his employment or contract with the Commission, or his employment with such contractor. 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