Current topics in radiation research quarterly最新文献

{"title":"Investigation of tritium incorporation of tritium incorporation by means of excreted metabolites.","authors":"T Biró,&nbsp;M Szilágyi","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The commonly accepted urine analysis by liquid scintillation method was applied for whole body dose estimating. After the separation of metabolite fractions the organically bound tritium in urine could be measured. Urine samples from workers repeatedly exposed to tritium incorporation during the chemical processing of various labeled compounds have been collected and analyzed. The time dependence of tritium activity in certain metabolites was found to be characteristic, significantly differing from the 3H concentration curve of the native or treated urine sample.</p>","PeriodicalId":75768,"journal":{"name":"Current topics in radiation research quarterly","volume":"12 1-4","pages":"313-21"},"PeriodicalIF":0.0,"publicationDate":"1978-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11843039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chromosome aberrations in human lymphocytes exposed to tritiated water in vitro.","authors":"E Bocian,&nbsp;B Ziemb-Zak,&nbsp;O Rosiek,&nbsp;J Sablinski","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The induction of chromosome aberrations in human peripheral blood lymphocytes by tritiated water or 180 kV X-rays in vitro was studied. Lymphocytes were exposed to various concentrations of HTO for 2 h or for 53 h. Chromosome and chromatid type aberrations were scored during the first mitotic division after stimulation with phytohaemagglutinin. For the analysis of the dose-response relationship the data were fitted by the method of least-squares to different models. After acute exposure to tritium beta-rays and X-rays, the dicentrics + centric rings and terminal + interstitial deletions gave the best fit to the linear-quadratic function. However, data for these types of aberrations after 53 h exposure to HTO gave equally good fit to the linear and linear-quadratic functions. The best description of the dose-response relationship for chromatid aberrations is given by the linear model. In the system studied the RBE of tritium beta-rays as compared to 180 KV X-rays was 1.17 +/- 0.02.</p>","PeriodicalId":75768,"journal":{"name":"Current topics in radiation research quarterly","volume":"12 1-4","pages":"168-81"},"PeriodicalIF":0.0,"publicationDate":"1978-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11840977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The tritium RBE at low-level exposure--variation with dose, dose rate, and exposure duration.","authors":"R L Dobson,&nbsp;T C Kwan","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Differing values have been reported for the relative biological effectiveness (RBE) of 3H beta-radiation compared with X- and gamma-rays; but the significance of these differences has not been adequately clarified. Because large quantities of tritium are involved in nuclear energy operations, it is essential to have precise knowledge of its effectiveness compared with a \"standard\" radiation such as gamma-rays. This is especially true for chronic, low-level exposure since available information on protracted irradiation derives mostly from gamma-ray studies. We have approached this problem experimentally by measuring effects of low-level exposures to HTO and gamma-rays on a very sensitive mammalian system. Microscopic enumeration of oocytes in ovaries of exposed and control mice provided measurements of in vivo cell killing by constant HTO levels in body water and, for comparison, by continuous 60Co gamma-irradiation. For protracted exposure from conception to 14 days after birth, the RBE was found to be greater than 1 and to vary inversely with exposure level. At effective gamma-ray doses of 50 rad, delivered at 3.5 rad/day, the RBE was 1.6. But for 25 rad, at 1.8 rad/day, it increased to 1.9. It continued to rise as dose decreased, reaching a value of 2.5. Corrected for scattered radiation, the RBE was 2.8, close to 2.9 reported previously, but below the maximum value of 3.75 predicted by microdosimetric measurements and the theory of dual radiation action. An RBE close to 3 at low doses was not suprising. But decrease at higher doses, due to downward curvilinearity of the gamma-ray dose-response curve, was unexpected for protracted exposure. It suggested that primary oocytes in the prepubertal mouse (the cells used in this study) have limited capacity for recovery. Survival-curves for constant gamma-ray dose rates of 1 rad/min and 0.002 rad/min were therefore determined. Curvilinearity was seen in both, with greater steepness for the higher dose rate, indicating that oocytes do have some ability to recover, but that even with a dose rate only 3.2 rad/day recovery is incomplete. This in turn suggests that the observed gradient in RBE is due partly to a dose-rate effect and partly to inverse variation with dose itself, as predicted by the theory of dual radiation action for acute exposure (or incomplete recovery). Comparing protracted and shorter, 5-day exposures revealed further contrasts. At 30 rad of gamma-rays the RBE in short exposures was only 1.4, while it was 2 for protracted ones. This could be due at least in part to dose rate; it may to some degree, however, reflect difference in microdistribution of tritium atoms, greater radiobiological effect in protracted exposures resulting from 3H incorporation into especially effective sites. These systematic variations of RBE with dose, dose rate, and exposure duration help to explain some of the existing lack of agreement regarding tritium's RBE and provide a more secure basis for hazard ","PeriodicalId":75768,"journal":{"name":"Current topics in radiation research quarterly","volume":"12 1-4","pages":"44-62"},"PeriodicalIF":0.0,"publicationDate":"1978-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11841782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The bromine enhancement ratio in mammalian cells in vitro and experimental mouse tumours.","authors":"G Tisljar-Lentulis,&nbsp;L E Feinendegen","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Human kidney cells in culture and cells of mouse sarcoma-180 were allowed to incorporate bromine into their DNA. Cultured cells with and without incorporated BUdR were irradiated with electromagnetic radiations ranging in energy from 12 keV X-rays to 60Co gamma-rays to find out whether or not there exists any energy dependence of the bromine dose enhancement ratio BER. Such a dependence should show in the immediate neighbourhood of the K-absorption edge of bromine (13.5 keV). Any influence of the Auger effect triggered in bromine by external irradiation should show by a significant increase of the BER for energies rising from slightly below to slightly above the bromine K-edge. Values of D37, D0 and the extrapolation numbers of the cell survival curves served as biological endpoints. Measured values of BER ranged from 1.12-2.00 without any significant dependence energy. A weakly pronounced peak was found for 50 kV X-rays of 26 keV mean energy. Sarcoma-180 were irradiated with 14 kEV X-rays and 60C gamma-rays. BUdR was administered i.v., i.p. and directly into the tumours in quantities of up to 1 ml of a 10(-3) M solution. Tumour regression caused by the irradiations served as a measure of the radiation effects with and without incorporated BUdR. No significant dose enhancement effect of bromine was observed in this case. Within error limits, the combination of BUdR with 14 keV X-rays proved more effective than BUdR combined with 60Co gamma-rays.</p>","PeriodicalId":75768,"journal":{"name":"Current topics in radiation research quarterly","volume":"12 1-4","pages":"526-36"},"PeriodicalIF":0.0,"publicationDate":"1978-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11841786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The use of nitroaromatic compounds as hypoxic cell radiosensitizers.","authors":"P Wardman","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":75768,"journal":{"name":"Current topics in radiation research quarterly","volume":"11 4","pages":"347-98"},"PeriodicalIF":0.0,"publicationDate":"1977-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11542700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tunnelling in radiation chemistry.","authors":"W M Bartczak,&nbsp;J Kroh,&nbsp;E Romanowska,&nbsp;C Stradowski","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>This review is devoted to the radiation chemistry of frozen systems with emphasis on the recent theoretical and experimental investigations suggesting tunnel character of trapped electron transfer to scavenger molecule.</p>","PeriodicalId":75768,"journal":{"name":"Current topics in radiation research quarterly","volume":"11 4","pages":"307-46"},"PeriodicalIF":0.0,"publicationDate":"1977-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11542699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Irradiation of cells by single and double pulses of high intensity radiation: oxygen sensitization and diffusion kinetics.","authors":"E R Epp,&nbsp;H Weiss,&nbsp;C C Ling","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The biological effects of ionizing radiation in living cells are the ultimate result of a long chain of events with the initial step being the local absorption of radiation. Whereas such physical abosrption is probably over within 10(-16) s after dose delivery, the biological consequences of radiation do not manifest themselves until very much later times. Between these two extremes of time, events occur relatively early at the molecular level which are undoubtedly critically related to the still unknown basic mechanisms of cellular radiation damage. These events may include not only the interaction of highly reactive species produced within the cell but also the diffusion of molecules such as oxygen or other chemical radiosensitizers.</p>","PeriodicalId":75768,"journal":{"name":"Current topics in radiation research quarterly","volume":"11 3","pages":"201-50"},"PeriodicalIF":0.0,"publicationDate":"1976-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12012442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cytological factors and their predictive role in comparative radiosensitivity: a general summary.","authors":"A G Underbrink,&nbsp;V Pond","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Various cytological factors, including interphase chromosome volume (ICV), nuclear volume (NV), cell volume, DNA content per nucleus and per chromosome, have been reviewed to determine their usefulness as indices to predict radiosensitivity. Fourteen topics are discussed. They are: a historical development of the concept of using karyotypic features to estimate radiosensitivity; interrelationships between cellular parameters; relationship of the karyotype to the duration of mitosis and meiosis; relationships between chronic and acute irradiation and ICV using several radiobiological end points for woody and herbaceous species; correlations between dose and cellular parameters ftween chromosome aberrations and cellular characteristics after chronic irradiation; polyploidy and plant radiosensitivity; radiation-induced petal mutations in plants and their relationship to cellular parameters; correlations between mean survival time facter irradiation and cellular parameters in amphibians and higher plants; correlations between radiobiological end points and cellular parameters after whole-body irradiation in amphibians. insects and mammals; correlations between radiosensitivity and cellular parameters in diverse single-cell organisms; correlations between radiobiological end points and cellular parameters in higher plants irradiated with neutrons and the value of cell parameters to estimate relative biological effectiveness (RBE); and energy absorption and trends in radiosensitivity among species and radiobiological end points. It is concluded that ICV is usually the most useful parameter for predicting radiosensitivity.</p>","PeriodicalId":75768,"journal":{"name":"Current topics in radiation research quarterly","volume":"11 3","pages":"251-306"},"PeriodicalIF":0.0,"publicationDate":"1976-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12217731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photochemical inactivation of enzymes.","authors":"L I Grossweiner","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The mechanisms of enzyme inactivation by ultraviolet light and visible light in the presence of sensitizing dyes are reviewed. Recent flash photolysis studies on amino acids and enzymes are summarized in terms of proposed models relating the initial photochemical reactions to permanent chemical and biological damage. The generation and reactions of singlet oxygen are discussed in connection with photodynamic processes. The photochemical results are compared with ionizing radiations, particularly pulse radiolytic methods employing radical anions as selective probes. The interrelationships between the various modes of enzyme inactivation are discussed, as well as the new information to be learned about the structure and functions of the native enzymes from selective radiation-induced alterations.</p>","PeriodicalId":75768,"journal":{"name":"Current topics in radiation research quarterly","volume":"11 2","pages":"141-99"},"PeriodicalIF":0.0,"publicationDate":"1976-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11964704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An historical survey of radiobiology and radiotherapy with fast neutrons.","authors":"S B Field","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The treatment of cancer using fast neutrons was first attempted from 1938 to 1942, only a few years after the identification of the particle in 1932. The radiobiological information which was available at that time was both inadequate and contradictory, and provided no definite rationale for using neutrons in preference to X-rays. The doses given were often too high, causing many patients to suffer severe late reactions. As a result, further attempts to use fast neutrons in radiotherapy were abandoned for nearly 30 years. Interest in the use of fast neutrons was stimulated again by the elucidation of the oxygen effect and the discovery that it was less for neutrons than for X-rays. Thus tumours containing hypoxic cells would be less protected against neutrons. Also the reduced repair of sublethal damage with neutrons provided at least a partial explanation of the miscalculation of dose in the early trial. This was confirmed by means of a series of experiments on pig skin, from which it was also concluded that late damage was not more severe after neutrons, compared with X-rays for a given degree of early damage. A new clinical trial began in 1966, and the results so far are encouraging. In order to relate radiotherapy experience with X-rays to neutrons, it is necessary to measure the relative biological effectiveness (RBE) of neutrons. This has been done for skin of man, pig, mouse and rat. Because of the smaller recovery from sublethal damage after neutrons, the RBE increases as the dose per fraction decreases, but the relationship between RBE and dose per fraction is the same for all four species. Similar information, but only for rodents, has been obtained for a variety of other normal tissues with both cyclotron-produced and monoenergetic 14 or 15 meV neutrons. Experiments with animal tumours have indicated that there might be a wide variation in RBE from tumour to tumour due both to the presence of hypoxic cells and to differences in their capacities to recover from sublethal damage after X-rays and neutrons. The largest series of experiments on one tumour shows that whereas certain fractionation techniques with X-rays may produce a poor tumour response for a given level of normal tissue damage, all the neutron regimes produced a similar, close to optimum result. There is no evidence from which to expect any special dangers from neutron irradiation, and their likely advantage is that they may provide a more reliable method of radiotherapy as well as sterilizing some tumours which are normally resistant to X-rays.</p>","PeriodicalId":75768,"journal":{"name":"Current topics in radiation research quarterly","volume":"11 1","pages":"1-86"},"PeriodicalIF":0.0,"publicationDate":"1976-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12287886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}