Meeting of the Advisory Committee for Biology and Medicine May 10-11, 1963 Presentation Program (AEC-Acbm 98)

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ADVISORY COMMITTEE FOR BIOLOGY AND MEDICINE UNITED STATES ATOMIC ENERGY COMMISSION AEC Contract AT (30-1)-901 New England Deaconess Hospital achusetts Institute of Technology Harvard Medical School

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ADAPTIVE ENZYME CHANGES IN ANIPAL TISSUES We have studied mainly two enzymes of liver, the tryptophan pyrrolase and the tyrosine transaminase, which were found to adapt their activity to the physiological condition of the animal, taught us something about the quantitative controls of specific protein synthesis and breakdown. today with the organismic or regulatory aspects of living systems. These studies up to now have This is part of a larger preoccupation of biology The major phenomenon consists of rapid and large changes per cell i n This can be producedthe amount of the newly synthesized enzyme protein. in two different ways: hormone and substrate-type inductions, ihe first is a specific effect of the glucocorticoid hormones on the liver cell, to increase some limiting species of RNA, so that the.synthesis of the specific enzyme protein is accelerated without change in the rate of its combine with the enzyme. The mechanism appears to pull the synthesis of the protein more rapidly through the existing RNA machinery. We believe that the finished product is trapped and its breakdown prevented by coinbination of the enzyme with its substrate, its coenzyme, and its inhibitors. The second way is produced by substances which specifically Re are now looking for proof of the suggested mechanisms. A s presented, they offer a remarkably simple way for the enzymic machinery of a cell to be adjusted to its function: the more enzyme is tied up in its functional conplexes, the more is formed. This is a simple basis for disuse atrophy and work hypertrophy, by which whole segments of the metabolic machinery would exist in amounts proportionate to their function. offers a means by which a chemical signal could alter the course of metabolism. A hormone-induced change in a critical step would then be followed by substrate-type-induced sequentia1 changes throughout the p z w mC~l’* The hormonal mechanism

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Other mechanisms also operating in the adaptive control of these< . . enzyme activities have been noted but not yet investigated. It seems to be clear that the gene action by which these particular proteins are made by a given tissue is separately controlled from the hormone and substrate-type inductions already described. Thus the enzymes are absent from, and cannot be induced in, pre-natal liver. They cannot be induced in other.tissues at any stage of life. After birth, the basal levels of the enzymes appear in liver, and only then can the amounts be modulated by induction. It would appear that the genetic information whiclTmust be present in every cell, becomes available in only certain cells at certain stages of differentiation, in response to an unknown type of signal.

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SUSPECTED INTERFERENCE WITB ThYMIDIKF INCORPORATION OF MOUSE THYROID NUCLEI AFTER VERY LOW DOSES OF 1131 In the course of experiments on the interaction of thyroid and-pituitary thyrotrophs during drag and low dose radioiodine treatment, tritiated thymidine was administered to observe whether stimulation.or depression of thyrotroph or thyroid parenchyma cell division would occur, Although adequate doses of tritiated thymidine were used and good radioautogram of adjacent tissues were obtained, no labelling of pituitary tissue was seen i?n the control, drug or I13'-treated animals. On the other hand, control and drug treated thyroid glands yielded an average of 11 and 6.5 labelled cells per section respectively, The radioiodine-treated animals averaged less than 0.2 labelled cells per section in animzls which had received 2 5 j c and which had retained an average of 2.1~11~(range 1 to 3.25 pc) at approximately 24 hrs. and less than 0,4 labelled cells per section in animals which had received 5 0 y c and retained an average of 3 . 3 ~ ~(range 2 to 5 p c ) at (Rockland RAP strain) receive a dose of 7 to 10 rad per trappedpc of 113' if It has been previously determined that the thyroids of these mice allowed to act for seven half lives. S i m e the a.nimls were kilied on the seventh day after 1131 administration, it is: considered that these thyroids received 45 percent of the total possible dose or 3 to 4.5 rad per trappedyc, that over a range of 3 to 22.5 rad per thyroid serious interference with thymidine In a parallel series 'inwhich the mice were killed on the third day, similar results occurred except that difficulties with the controls preclude serious consideration of the three-day data, Radiation interference with DNA formation at higher total body doses has The possible reasonsfrequently been reported but never with such low doses. for the effectiveness of such low doseswill be discussed.

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STUDIES IN RADIATION CARCINOGENESIS This presentation will be concerned with a discussion of a selected number of present and future investigations. 1. The Incidence -of Leukemia &I Patients with Cancer --of the Cervix Uteri Treated with Radiation. (1960 - 1967). This study deals with the question whether conventionA1 radiotherapy of cancer of the cervix uteri with X- and gamma rays, which always entails exposure of a portion of the bone marrow, increases the risk of these patients to develop leukemia, This prospective epidemiological investigation is being conducted, in part, under the auspices of the World Health Organization. It is performed through the active collaboration of physicians in 31 clinical centers here and abroad. A little over 15,000 patients are enrolled in the study at present. The coordination of this investigation and the collection of the data are being the-Department of Epidemiology of the tiarvard School of Public Health. 2. The Induction -of Tumors in Mice with Radioactive Thymidine.- (1960 - 1964). It is the aim of this investigation to explore the possibility of inducing tumors in mice with a mode of irradiation that affects primarily the cell nucleus (tritiated thymidine) or whole

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cells (carbon-14 labeled thymidine). It has been demonstrated that both materials are effective in producing a variety of malignant tumors in mice under various experimental conditions. done in collaboration with Dr. R. Baserga of the Department of - Pathology of Northwestern University Medical School in Chicago and with Dr. W.E. Kisieleski of the Argonne National Laboratory. This work is being 3. Comparative Studies on the Induction of Breast Tumors --in Rats It is the purpose of this investigation to extend to the breast tissue of the rat the aforementioned observations in mice on the induction of tumors with radioactive thymidine, to compare carcinogenesis produced by radiation with that produced by carcinogenic hydrocarbons, and to study various aspects of this carcinogenic process in greater detail. The breast tissue of female Sprague-Dawley rats is peculiarly susceptible to tumor induction by carcinogenic hydrocarbons and by radiation. A single experiment can now be done in a few months' time (3-5 months), in contrast to the long duration of such an experiment in the mouse (1-3 years). carbons and of external radiation the experimental design envisages the In addition to the use of carcinogenic hydrouse of tritiated thymidine both a s a carcinogen and as an indicator of cellular proliferative activity under various experimental conditions. This investigation has recently been started with the help of Dr. J. Solis of the Cancer Research Institute. No results are available 4 . Observations --on Bone Pathology of Patients with Chronic Radium Poisoning. (1963 - ). These studies will be concerned with the histoDQE ARCH IV ~ pathologic, micro-radiographic and autoradiographic changes in the

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bones of patients with chronic radium poisoning who are currently under observation by Professor R, D. Evans and his colleagues at the Radioactivity Center at the Massachusetts Institute of Technology. will be the aim of these studies to produce a correlation of the distribution of radium in human bones (gross and micro-autoradiography) with in bone, and to relate all of these changes to radiation dose (gross accurately than heretofore possible the histopathology of the bones and An attempt will a l s o be made to describe more the histogenesis of the bone tumors under these conditions of radiation exposure. These studies will be done in cdoperation with Professor

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A SURVEY OF EXPOSURES RECEIVD BY IIOSPI'IIALIZED PATIENTS DURING ROUTINE DIAGNOSTIC X-RAY PROCEDURES F r o m the survey of 2605 patients that were admitted for diagnostic studies in the x-ray department of eight hospitals in Massachusetts, it was found that the dosage to those under 30 years of age was considerably lower than to those between 51-70 years of age. The ratio of patients under 30 years of age in relation to the total patients subjected to x-ray examinations was found to be less than 11 per cent. Patient dosa.ge may be decreased by as moth as 25 per cent in the average x-ray department when properly trained technicians are employed and when fluoroscopic examinations axe carried out by experienced radiologists. Stildent technicians should be closely guided by senior personnel.

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STUDIES ON THE ELBS PERSULFATE OXIDATION: AN ASPECT OF PEROXIDE CHEMISTRY In 1893, K. Elbs found that the reaction-'between o-nitrophenol and persulfate in aqueous base led to the formation of nitrohydroquinonemonosulfatewhich, upon acid hydrolysis, yielded nitrohydroquinone Interest in the general problem of aromatic hydroxylation has stimulated a mechanistic study of this reaction. The kinetics have been shown.tobe first-order in both phenolate ion and persulfate. rate of the reaction by the sulfate radical trapping agent, allyl There is no inhibition of the , acetate. Studies with a number of substituted phenols have shown acceleration of the rate of the reaction by electron-donating attack of persulfate on the phenolate ion. of persulfate as an initiation step is considered improbable. evidence from Ham ett sigma-rho correlations favors rate-limiting attack at oxygen. These results are consistent with electrophilic Homolysis or heterolysis

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EXPERIMENTAL STUDIES IN THE ANEMIA OF MALIGNANCY For the past few years we have been studing ihe anemia of malignancy as one manifestation of the complicated tumor-host relationship, A s o w experimental model we have employed the tumor-bearing golden hamster, using the various transplantable hamster tumors maintailed in OGT laboratory. Three different tumors, a fibrosarcoma, an amelanotic malignant melanoma, and a carcinoma have been used most often in these studies. Growth of each of these tumors is associared with the development of a normocytic, normochromic anemia(mch like-that seen in humn cancer patients) which can best be described as an incompletely compensated hemolytic anemia, Neither frank hemorrhage nor infection appear to be sigQificdnt factors in its pathogenesis, and the anemia develops before cachexia or distant metastases are One hematologic abnormality which appears in tuinor-bearing hzimsters before the onset of anemia is a positive erythroagglutiaation reaction (EAR). reaction is checked by adding tnheated, undiibted, rabbit anti-normal-hamster- - serum serum (absorbed with erythrocytes froxi normal hainsters) to a three percent saline suspension of the test red cells and observing whether or not agglutination hamsters and humans a positive EAR will a l s o be present in certain nonneoplastic conditions, e.g., pregnancy and active inflammation, The EAR is also positive in hawn patients with cancer, but in both At this time, particular stress is placed on an investigation into the basis for, and the significance of, the positive EAR in tumor-bearing hamsters and in human caxer patients e

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CHROMOSOMAL ABNORMALITIES INDUCED BY THERAPEI?TIC IRRADIATION By using the relatively convenient method of blood culture, w6 are now able t o assess directly the effect of irradiation on chromosomes of norm1 human cells. For this study w e have selected patients who have large portions of bone marrow o r spleen irradiated in the co.irse of x-ray therapy. By analyzing chromosomes of cells from cultures grown at intervals during the course of their treatment w e are able t o determine the frequency of variation from the normal chromosome number of 46 as well as the incidence of structural abnormalities. I n our control cultures atleast 85 percent of the cells counted have been found t o have the normal chromosome number of 46. Following irradiation, the frequency of such normal cells may drop t o as low as 40 percent i n some patients. However, once the minimum i s reached the frequency of cells which have abnormal chromosome numbers does not conti rue to increase wit.h radiation dose. 'Ihe frequency of abnormal cells that can be tolerated seems t o be quite patient specific and may persist unchanged for as long as two years after the conclusion Radiation induced struct.cira1 aberrations seem t o be largely random i n terms of chromosomes affected, except that the largest chromosomes a.ppear t o be most frequently broken and involved in di centric s a.nd tram locations. We consistently see a centric fragments i n radiation-damged cells, and also many missing chromosomes. There are frequently more than the norma.1 number of small acrocentric chromosomes, some of which resemble the Philadelphia chromosome.

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THE EFFECTS OF INTERNALLY DEPOSITED EAD ZL MAM I ?iESOP'ti_OI(IzIM IN HUMAN BEIYLS (Massachusetts Institute of Techrrology) When radium is radium is deposited taken into the human body a small fraction of the and retained in the bones. Soft tissue retains substantially no radium. is sufficiently large, clinical effects may be seen after one to four If the amount of radium retained in the skeleton decades and may include bone necrosis, osteoporosis, spontaneous fracture, osteogenic sarcoma, or carcinoma of the paranasal sinuses or mastoid. Our long-range goal is the quantitative determinat:ion of this dose-vs.- response relationship, in -man. This involves teamork between physicists (for evaluation of the radiation dose) and physicians (for evaluation of the biological response). An x-ray scoring system f o r the numerical evaluation of biological response in terms of skeletal changes has been developed in colla.boration with Argonne Cancer Research Hospital and with Argolne National Laboratory. The alterations in normal bone that simulate chaages seen as a resiilt of radium deposition and which are present in the r,ormzl poplilation have been evaluated in a group of 120 aging-control persons. evaluation of body burden has been interchecked by exchange of phantoms Thus far, more than 300 persons have been studied at the Massachusetts Institute of Technology since 1934. Also, about 260 other persons have been studied at the Argonne National Laboratory'diiring the past decade. The results are in comforting agreement. More than 100 of the persons whose dose and response have been

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shorter-lived isotope, mesothorium (Ra-228). In some of these mixtures mesothorium accounted for as much as 9 0 perceit of the skeletal radiation dose. Tentatively, we have expressed these combined doses, in average rads to the skeleton, on a scale of equivalent radium-226, which we call MPRE (minimum pure radium equivalent), by making the limiting assumption of zero initial skeletal absorption of the radiothorium (32-1-228) which was ingested along . with its radioactive parent mesothorium (Ea-228). The domain up to about 0-5 microcurie residual MPRE appears to involve no unequivocal case with clinically significant symptoms attributable to internal irradiation. The Radiation Protection Guide (RPG) of 0.1 microcurie of radium maximum burden involves a cumulative dose which is clearly conservative, by a factor which …