U.s. AEC Advisory Committee for Biology and Medicine Program March 13, 1964

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UNIVERSITY OF CALIFORNIAy LOS ANGELES SCHOOL OF MEDICINE DEPARTNENT OF BIOPHYSZCS AND NUCLEAR MEDICINE LABORATORY OF NUCLEAR MEDICIlQE AND RADIATION BIOLOGY UNITED STATES ATOMIC ENERGY COMMISSION ADVISORY COHMITTEE FOR BIOLOGY AND WDICINE

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UNITED STATES ATOMIC ENERGY COMM'LSSION ADVISORY COMMITTEE FOR BIOLOGY AND MEDIC'IW UNIVERSITY OF CALIFORNU, LOS ANGELES LABORATORY OF NUCLEAR MEDICINE AND WIATIOP4 SIOLOGY Dean, School of Medicine Dean, Graduate Division Director, Laboratory o f Nuclear Medicine 6 Radiation Biology Relative Sensitivity of Pyrimidine Compounds to RadiatLon The Protective Effects of Bromide on Irradiated Nucleoprotein Constituents In Solution Direct Effects of Ionizing Radiation on Free Fatty Acids Studies of Aging in the Brain Metabolic and Cytological Studies of Cultured Reart- Cells Mechanisms of Mitochondrial Formation Response of Nervous Sy c teen tc TonFZfng Radi aEi on

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Advtsory Committee for Biology and Medicine Meeting Nucleic Acid Transmission of Leukemia in Mice Close-in Effects of Operation Sedan on Vegetatfon and Iodine-131 in Thyroids of Jack Rabbits After the Sedan Test Long-term Radiation Studies of a Desert Ecosystem Kinetic Studies of Calcium Absorption and Placental Transport in Man and the Monkey Erythropoietin in Cerebellar Hemangioblastoma Quantitative Radiorenography for Evaluating Renal Artery Organ Scanning with Radioalbumin Aggregates (Basic Studies and Clinical Applications) Optional: Visit to Laboratory

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Objectives and Program The objectives of the Laboratory may be summarized in seven major interrelated categories as follows: 1. investigation of the effects of ionizing radiation on systems of biological significance and on living organisms, and investigation of methods of minimizing or preventing the detrimental effects of 2. Investigation of the dynamic aspects of physiological and biochemical processes in man, animals, and plants and study of how these processes are modified by radiation and related pathological states. 3. The development of,beneficial uses of ionizing radiation and radioactive substances in medicine and biology. 4 . Assessment of the contamination of our environment by radio-active materials; study of the transport of these materials into living ' organisms; and the evaluation of the effects of the accumulation of these substances upon the health, function and structure of these 5 , Research and development of new and more efficient radiation detection 6. Research including field studies and operational assistance to the AEC in connection with the conduct of weapons tests and biomedical and civil effects experiments at such tests conducted at the continental and overseas test sites. 7. The provision of graduate and post-doctoral education and training in ?he biological and medical aspects of radiation and related fields. Prinary emphasis is placed upon research endeavours, but with the firm klief ttLat : i t - iesz: arid most imaginative research is accomplished in a teaching envi:onnent, an educational program at graduate and post-doctoral levels has been d?.i+lcp:ed during the past 3 years. This has had a salutary effect YPon the res2arc.h programs of the laboratory, and additionally has been of great v a l L c in attracting bright young men and women to the important areas o f radiation biology, nuclear medicine and environmental radiation. A summary of research endeavours in progress is given in the Semiannual Progress Seport of December 31, 1963, (UCLA Report #520) which was forwarded to each member of the Advisory Committee for Biology and Medicine on February Representative examples of this research will be presented on March 13 and are summarized in the following abstracts.

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The Department of Biophysics and Nuclear Medicine provides graduate work enrolled in this program and 10 of these students are working inthe Laboratory of Nuclear Medicine and Radiation Biology under the supervision of the Laboratory staff. awarded i n June of this year. At present,21graduate students are It is anticipated that three Ph D. degrees will be An active post - doctoral training program has been developed. During 1962-1963$ 22 visiting scholars and post - doctoral fellows participated in our research programs, with great profit both to themselves and to our research The department gives a lecture course to freshmen medical students in Additionally,during the summer sessions which fundamental concepts of molecular biophysics,radiation biology and nuclear medicine are introduced - 8-10 medical students work in the Laboratory as research assistants 1963 seven of these medical students were enrolled for credit in the Graduate Further details of the educational program are provided in the Annual Report for 1962-1963 of the Department of Biophysics and Nuclear Medicine and Laboratory of Nuclear Medicine and Radiation Biology, which i s provided here - The Laboratory of Nuclear Medicine and Radiation Biology is the depart - mental laboratory of the Medical School Department of Biophysics and Nuclear t ration, and the research and training programs of the Laboratory - This department i s charged with the responsibility for the adminisThe staff of the Laboratory is organized into one administrative and seven research d'ivisions. (See the appended table of organization). The staff t arial and clerical ; and 60 other supportive personnel ; a total of 214. Thirty - thee of the academic personnel are research series appointees, and of these staff hold tenure faculty appointments and two members are supported by USPHS Research Career Awards. The activities of the Laboratory and Department are coordinated by the Director-Chairman and an Advisory Committee composed of tenure rank staff and Division Chiefs- All academic staff convene a t monthly departmental meetings. The Laboratory o f Nuclear Medicine and Radiation Biology structure was completed and occupied during the summer and fall of 1961, and has proved t o be a superb facility for research and education. square feet of laboratory,office and shop space - It provides 90,000 gross

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Physical Fac ili cie s(cont.) The major portion of the research program i s conducted inthe Laboratory of Nuclear Medicire and Radiation Biology, but some work is carried on i n 1. The clinical aspects of nuclear medicine are conducted by D r - Tap lin and his collaborators at the Los Angeles County Harbor Hospital, 20 miles south of the Laboratory. There are 8staff personnel working in the la bota tory at the hospital, which has been equipped and supplied with funds from Contract GEN-12. 2 . 'Programs in radio ecology are conducted atthe Nevada Test Site, currently8full - time employees work there, and an additional 10 of our staff spends variable amounts o f time there. 3. A study of the cycling of fission products in an agricultural system is in process on a dairy farm i n Utah. Three of our staff work. a t this site on occasion. 4 . The total body counter, and a newly.developed scanning device designed for localization of intra cranial tumors are houised inthe UCLA Medical Center -

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RELATIVE SENSITIVITY OF PYRIMIDINE COMPOUNDS TO RADIATION The relative sensitivity of the chromophoric group of various pyr imi dine compounds to the indirect action of Coy - radiation has been investigated by spec tro photometric techniques. For any parti - cular compound the sensitivity depends on the pH, generally dec reas - ing as the pH is increased from low values, through the physiological region,to high values. Accordingly experiments have been done i n neutral solutions and atthe pH extremes to determine the maximum extent of the variation and its relation to amino, methyl,pen tose, and pentose-phosphate substituents.In acid and neutral solutions, i n which the pyr imi dines are positively charged or neutral,the initial disappearance yield of the c hro mph ore(orthe5,6double bond) is about the same for thymine, uracil,cytosine, 5-methyl cyto - sine, and the corresponding nu cleo sides, approximately 3 molecules/ 100 e.v. absorbed. It is also the same for cy tidy lica cid in acid, but somewhat lower in neutral solution.In alkaline solution,in which the pyr imi dines are negatively charged, the results are complex and depend markedly on the side chains. Thus with uracil and cytosine the yields are initially about the same as in acid,but rapidly decrease with increasing dose. They are essentially zero with compounds which have a methyl group inthe5position.In compounds which have a sugar attached to the ring,the disappearance yield is again zero if a 5-methyl group is present.If it is not, the intensity of the chromophore increases when the nu cleo sides are irradiated.A similar increase was obtained with cy tidy lica cid. These results are consistent with the view that in the positively charged or neutral molecules the5,6 double bond isthe most sensitive group to irradiation but that in the ionized forms the methyl and sugar groups are also attacked if present.

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THE PROTECTIVE EFFECTS OF BROMIDE ON IRRADIATED NUCLEOPROTEIN CONSTITUENTS IN SOLUTION OH free radicals, produced by absorption of ionizing radiations i n water have little specificity as tothe compound they will attack within the living cell. However, the free radicals wtzich they produce by reaction with substances within the cell will be less reactive and may migrate to a sensitive cell " target " . We have been examining the effect of halide ions on radiation yields from nu cleo - protein constituents in solution in order to investigate (a) the reaction mechanisms of OH with the halide ions and (b)the importance of halide ions in sensitizing or protecting cellular components. Previous work has shown that chloride ions do not react with OH free radicals above p H 3.0 and thus do not have an appreciable effect on radiation decomposition of nucleic ac ihs or their constituents in neutral solutions. Bromide ions, however, do react with OH' in neutral solution to produce bromine atoms which are much less reactive than OH'. Thus the presence of bromide ion protects some compounds i n solution ; the bromine atoms produced react further with 0- ion radicals causing a decrease in hydrogen peroxide yield. Compounds such as cyst eine which react with Less reactive free radicals,i.e., 0- are not protected by bromide since they react with bromine atoms. Compounds which react by OH add ft ion and hydrogen abstraction such as thymine, ethanol, and DNA (assayed chemically and biologically) are protected - the latter by a factor of 100 rat loe1 Br. Since bromide ions protect the DNA compounds outside the cell,it i s of interest to find out their effect - & vivo. Experiments are in progress to investigate the effect of BY on, (a> cell death and (b)decrease in DNA transforming activity caused by ionizing radiation.

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DIRECT EFFECTS OF IONIZING RADIATION ON FREE FAnY ACIDS Early investigations of the consequences of exposing free fatty acids to ionizing radiation were prompted by interest in a possible explanation for the origin of petroleum deposits. carbon (and carbon dioxide)were indeed observed among the products of Saturated fatty acid irradiation,together with hydrogen and illdefined polymeric.materia1.Studies involving oleic acid disclosed moreover, that carbon - carbon double bonds may become saturated under these conditions.Curiously,the hydrocarbon obtained by Irradiation of oleic acid was reported to be trans - 8 - hepta de cene,implying that geometric(cis3trans )-- isomer iz ation of the double bond and de carboxyl a - tion are concomitant reactions.Repetition of this work (except for use of Co y - rays instead of deuteron s)yielded hydrocarbon having essentially the same infrared absorption characteristics as those originally reported,but comparison with nu then tic samples of both cis - and trans - 8 - hepta de cene showed that r he -c is olefin is in fact strongly predominant, although accoinpanicd b y some trans and term ally unsaturated material as well.As expected (assuming isomer iz ation and decarboxylation to be concurrent but independent events),the recovered (otherwise uncliznged) fatty acid also conC:;ins somc trans unsaturation. Exploring t'hc possibility that the last might acc u ally represent newly the exist is g double bond), st carica cid wa.: irradiated under the same conditions. ; ; zither the recovered s tea ric acid nor the hydrocarbon formed from it(in yi cid some seven tiiries that obtained from oleic acid with the same dose,4.5X 10 r) contain appr eca i ble trans - unsaturation. These unexpected observations reveal that1)prc scn ce of a carbon-carbon double bond in the fatty acid molecule inhibits de cz r box yl ation ; and 2) that presence of the carboxyl group prevents not only intra - but also inter - ml ecu lard es2.tu ration.Itis proposed that the electron hole produced by the initial ionization(electron ejection)migrates efficiently to sites o f lower energy(olefin ic or carboxyl groups)before further chemical

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DEGRADATION OF THE MYELIN LIPIDS Studies carried out in this and other laboratories have revealed the presence of very Long-chain, odd - chain and alpha hydroxy acids in the brains ph in go lipids.Until recently none of the known mechanisms could explain the existence of the latter two types despite considerable interest in their unusual structure and positive relationship to aging. In This Laboratory a theory has been proposed which could account €or the existence of both the - odd and hydroxy acids as arising from a single de gra dative process, which, in contrast to the usual pinvolves the following oxidative changes: Testing the theory in the whole animal involved the relatively simple (on paper) experiment of injecting young animals with carbo xy - labeled acetate and locating the label in the odd and even long - chain acids of their brains ph in go lipids after6 months. The finding that the even - chain hydroxy and un substituted acids had the C largely in the odd carbons was as expected from a consideration of ' the bio synthetic mechanism. The fact that in the odd - chain acids,the C was predominantly in the even carbons, supported a one-carbon deIn further studies,the enzyme o r enzymes resp on sib.le for the last ':w steps of the proposed scheme have been located in the brain microsomal fraction and their requirements and properties have been partially de1.j.ileated. Further studies are exp ecce d t'o reveal the nature of the first : :.:'iep and to clarify the overall process. The function in the brain of such a system isnot clear atthe mrnent butis of considerable interest. The products of the reaction c cup led with the knowledge that the reaction is not a likely source of c " e rgy for brain metabolism make likely the idea that it is a "scavenging" I ' i ' O Ces shaving as its function the removal of molecules that resist the rli-4i n a 1-17 degrada tion processes a nd mi. p, h to the mise ac cumulate. A1:tcinpts wF11 be made to scud y this process under a variety of con- :]:: C<.ons that might be accompanied by demyelination.