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. Radioisotopes i n Medicineo8:.The pro s of the second advanced course in the use of isotopes i n medicine (presented i n September of 1953) have been completed, leaving only compilation of the index to be completed before the manuscript, under the title "Radioisotopes i n Medicine," is ready for final publication by the US Government PrintThyroid Uptake Calibration Committee. Caltbration Committee will be held i n Oak Ridge on October lb. mittee i s composed of scientists at leading US research institutions who are attempting t o standardize the methods of measuring the amaunt of radioiodine absorbed by the human thyroid gland. A meeting of the Th+oid Uptake , tentatively planned t o be held i n Oak Ridge i n 1956 under the auspices of the University Relations Division, the Mathematics Panel of CEWL, and t h e American Mathematical Society, has been discussed among members of the three organizations, and has now been deemed an activity of the American Mathematical Society. The proposed summer symposium on mathematics, sentation of a state science-fair work conference, being held atthe Ud vers it y of Texas October 6-8, institution in the presentation of a West Virginia science-fair work conference, t o be ccmducted a t Jackson's Mill, Weston, October 30 - The Institute is cooperating inthe preORINS will also act as a cooperating Representatives of the American Museum of Atomic Energy met a t the North Carolina Agricultural and Technical College, Greensboro, North Carolina, t o arrange fora science-fair work conference for Negroes i n North Carolina. This conference has been scheduled t o be held a t North Carolina A & T November 11-12; six Negro colleges and universities i n North and South Carolina w i l l participate, and the North Carolina Department of Public Instruction will cooperate inthe conaerence. Oak Ridge National Laboratory Distribution and Excretion of Uranium in Man. therapy of brain tumors, the investigation of t h e metabolism and toxiIn studies on the neutron city of uranium i n terminal post-operative brain tumor patients was concluded except for completion of tissue analyses. Henceforth, pre-operati ve brain tumor patients will be injected with low levels of enriched ' uranium for evidence of uptake of uranium i n brain tumor cells and f o r additional data on the excretion pattern. Paramecium aurelia, established by previous work, are recessive lethal mutations and inhibition of nuclear exchange a t conjugation. Two major inheritable effects of radiation in &ring irradiation, while the latter is
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a r e decreased by the presence of cysteine durin It has been shown that they-also differ in that the recessive lethal s irradiation and by low . - > temperature afterward, whereas t h e inhibition of exchange is unaffected The factors lrbich determine stage sensitivity must be q u i t e diffe'r&nt from- those which &e involved i n modification by oxygen concentration, cysteine, and these two treatments, Both effects are very much 1essy.ahm the radiation i s made. shortly before cell division postirradia Hon temperature Vnen Habrobracon eggs are irradiated in the fix& meiotic metaphase, terminal chromosome deletions are incurred which result i n bridges i n t h e second meiotic anaphase and bridge breakage during cleavage. sequent gene imbalance has been considered as the s m r c e of dominant become established in eggs irradiated in the first meiotic prophase, the question arises as tothe cause of dominant lethal it yin these eggs. Examination of dead embryos shows t h a t approximately 80%have been blocked in development atthe6thor 7th cleavage and that the nuclei are Feulgen negative. Thus, it appears that dominant lethal it yin these eggs - i s associated with interruption of deoxgribonucleic acid synthesis. To t e s t whether this action is caused by induced chromosomal deletions of fixed extent, the dead embryos from unirradiated triploid s were of aneuploid types. ment, it appears likely that the radiation effect on deoxyribonucleic acid synthesis is not necessarily brought about by t h e induction of . Since the breakage-fusion-bridge cycle does not appear t o The chromosone complements of such embryos coq rise a variety Since eggs from triploid s died during later developaberrations by 25O-k-q X-rays indicate that in the seed of --Vicia faba the radiation-induced breaks remzin open for the relatively long period of two hours. This plus the fact that a source of energy is needed for the breaks td close has led to the an clu sion that the breaks are a t A time-intensity experiment performed a t high X-ray intensities has provided curves indicating that, i n addition tothe type of break that stays open for two hours, there isindeed another type of break that closes i n the relatively rapid time of less than' three minutes more, this second type of break begins to close immediately after it first opens so that the number of this type is being decreased from the that the removal of metallic ions i s capable of breaking the chromosomes. The da%a accumulated so far f o r the lapidly closing breaks are consistent with the hypothesis that breaks of ionic bonds are produced. i n contrast. t o the data on the breaks which stay open for relatively long periods of time and which are more likely covalent. 0ther.experiments with chelating agents such as Versene indicate Biochemistq. The generalizations on the structure necessary for maximum radiation protective activity (ORNL-PYO5) were further substantiated by the preparation and testing of a new series of thiuwnium compounds.
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BIOLOGP AND MEDICINE I n addition, an excellent correlatioh was found between chemical tests was examined extensively for its biological activity.. It appears t o have about t h e same toxicity as S, B-aminoethy~sothinronium~Br.HBr(W)and t o be equally effective over afmr - fold range of dose (2,309 mg/mouse) against a lethal radiation dose. tec tion to mice when administered intraperitoneally up t o two hours before the radiation dose. Both AET and APT gave effective proPathology and pfiysioloa. In an attempt t o study t h e mechanism whereby transfused nonirradiated bone marrow enables t h e survival of otherwise lethally irradiated animals, rats irradiated with 750 $ of X-rays w e r e subsequently injected with homologous nonexposed bone marrm carrying an immunogenetic marker. Erythrocytes carrying the genetic Label were detected i n the peripheral circulation within 2-3 weeks, whereas controls injected with unirradiated marrow did not show em hro cyte s derived from the implanted marrow, to persist and function as long as IlO days, contributing up t o 80% of the peripheral ergthrocytes, These experiments suggest that the protective action of transfused bone marrow may result from the implant ation and prolifekation of the nonirradiated hemopoietic cells in the Tracer Studies in Microbial Metabolism. Apr evi op report on succinic acid, decarboxylase studies (oRNL-187n described an enzyme system from Marrow 5mplants have been observed combined cell- extracts of Propionibacterium and Veillonella, which fixed Thig transfer was dependent on the presence of D m (reduced diphosphopyridine nucleotide) and pyruvate. unique carboxylation mechanism, and t h a t this product (OCUS) was converted t o malate by the malic dehydrogenase system. It was propbsed that the C i Additional support for this hypothe is was obtained from tracer experithe presence of malonate to inhibit the direct conversion of succinylCall to malate through fumarate. The data obtained demonstrate the inhi bit ion of CO and fipNH, and $he accompanying increased labelling of the malate carboxyl. Only negligible amounts of labelled lactate were formed. In addition, it was observed that catal fli c amounts of malate will replace the requirement for succinyl-Cos during DPNH oxidation with this system Tracer experiments with the same system show'that pyruvate-2-Ca is con verted to lactate in the presence of catalytic amounts of malate.and . substrate quantities of DPMI. The spectrophotometric and tracer experi ments can probably be interpreted most simply as indicating that with (but not propionate) produetiin by addition of pynkate
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DPNH present, pyruvate is converted to lactate on a pathway, thmugh OAA and malate; catalytic amounts 'of the Cg fragment from malate decarboxylation furnish the (carboxyl) carbon required to initiate the cyclic process. The proof of the existence of the pyruvate t o OAA step (and its requirement for malate) e'stablishes the link for the malate-dependent conversion o f pyruvate to lactate through OAAe Mammalian Radiation Recovery. their effect on recovery fr m lethal body irradiation demonstrated that small in test in e, urinary bladder, and subcellular particulates o f adult rat liver are ineffective. given t o 28 irnadiated mice and 2 were living on the 18th day whereas a l l 5 X-ray control mice were dead by the 12th day, vi valis probably significant, Studies on the mechanism of action of bone. marrow tre a bent after total-body irradiation showed that the recovered mice that received isologous (sane mouse strain) bone marrow have a nearly-normal immunologic response torat red blood cell antigens and sheep red blood cell antigens. Recovered mice that reasived heterologous (rat) bone marrow showed no immunologic response torat fed 6lood cell antigens. Quantitative biologic studies demonstrated that recovery from irradiated bone marrow i s proportional t o the dose of injected lsologms bane marrow cells irrespective of the percentage of mice surviving a high white blood cell count) after irradiation resides in the white blood cell mass injected. The screening of tissues and agents for A suspension of rat chloroleukemia cells was This degree of surThe therapeutic action of leukemoid blood (very