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Tumor production in Syrian hamsters following inhalation of PuO/sub 2/--ZrO/sub 2/ aerosol

Description: Syrian golden hamsters of both sexes were exposed to aerosols of ZrO/sub 2/ containing PuO/sub 2/. The starting material in the aerosol generator also had a small amount of /sup 57/Co added as a tracer. The mixture of all three constituents was nebulized and the droplets passed through a heating column at 1000/sup 0/C. Aerosol sampling was accomplished with a cascade impactor and electrostatic precipitator. The median aerodynamic diameters in all inhalation runs were approximately 2 ..mu..m wit… more
Date: January 1, 1978
Creator: Thomas, R. G. & Smith, D. M.
Partner: UNT Libraries Government Documents Department
open access

Clonal theory of radiation carcinogenesis

Description: In some cases, usually involving high-LET radiations, the dose response at low doses follows a power function of dose with exponent less than one over a wide dose range. This type of response is of great interest since (a) it implies greater effect per unit dose at progressively smaller doses, and (b) it is not predicted by most models and theories of radiobiology. A theoretical framework is presented for responses having the above characteristics over a dose range extending over a factor of 10… more
Date: January 1, 1982
Creator: Baum, J.W.
Partner: UNT Libraries Government Documents Department
open access

DNA repair in spermatocytes and spermatids of the mouse

Description: When male mice are exposed to chemical agents that reach the germ cells several outcomes are possible in terms of the germ cell unscheduled DNA synthesis (UDS) response and removal of DNA adducts. It is possible that: the chemical binds to the DNA and induces a UDS response with concomittant removal of DNA adducts; the chemical binds to the DNA but no UDS response is induced; or the chemical does not bind to DNA and no UDS is induced. Many mutagens have been shown to induce a UDS response in po… more
Date: January 1, 1982
Creator: Sega, G.A.
Partner: UNT Libraries Government Documents Department
open access

Qualitative analysis of mouse specific-locus mutations: information on genetic organization, gene expression, and the chromosomal nature of induced lesions

Description: Analysis of mouse specific-locus (SL) mutations at three loci has identified over 33 distinct complementation groups - most of which are probably overlapping deficiencies - and 13 to 14 new functional units. The complementation maps that have been generated for the d-se and c regions include numerous vital functions; however, some of the genes in these regions are non-vital. At such loci, hypomorphic mutants must represent intragenic alterations, and some viable nulls could conceivably be intra… more
Date: January 1, 1982
Creator: Russell, L.B.
Partner: UNT Libraries Government Documents Department
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The revised International Commission on Radiological Protection (ICRP) dosimetric model for the human respiratory tract

Description: A task group has revised the dosimetric model of the respiratory tract used to calculate annual limits on intake of radionuclides. The revised model can be used to project respiratory tract doses for workers and members of the public from airborne radionuclides and to assess past exposures. Doses calculated for specific extrathoracic and thoracic tissues can be adjusted to account for differences in radiosensitivity and summed to yield two values of dose for the respiratory tract that are appli… more
Date: May 1, 1992
Creator: Bair, W.J.
Partner: UNT Libraries Government Documents Department
open access

The Toxicity of Inhaled Particles of Sup 238 PuO2 in Dogs

Description: This study was conducted to determine the toxicity of inhaled {sup 238}PuO{sub 2} in the dog. Inhalation was selected because it is the mostly likely route of human exposure in the event of an accidental airborne release. Of 166 dog in the study, 72 inhaled 1.5{mu}m and 72 inhaled 3.0 {mu}m activity median aerodynamic diameter particles of {sup 238}PuO{sub 2}. Another 24 dogs inhaled the aerosol vector without plutonium. The aerosol exposures resulted in initial pulmonary burdens ranging from 3… more
Date: January 1, 1991
Creator: Muggenburg, B. A.; Guilmette, R. A.; Griffith, W. C., (Jr.); Hahn, F. F.; Boecker, B. B. & Gillett, N. A.
Partner: UNT Libraries Government Documents Department
open access

Radiation damage and its influence on source requirements for high resolution x-ray holography

Description: Soft x-ray holography offers the possibility of obtaining high resolution, 3-D images of living cells and organelles therein. To achieve a specified resolution, a certain number of photons must be scattered by the smallest features of interest within the sample. This requires a certain irradiating fluence, the magnitude of which depends on the wavelength of the x rays and the scattering cross- sections of the features. Unfortunately, irradiation of the sample will be accompanied by the absorpti… more
Date: January 1, 1989
Creator: London, R. A.
Partner: UNT Libraries Government Documents Department
open access

Comments on mutagenesis risk estimation

Description: Several hypotheses and concepts have tended to oversimplify the problem of mutagenesis and can be misleading when used for genetic risk estimation. These include: the hypothesis that radiation-induced mutation frequency depends primarily on the DNA content per haploid genome, the extension of this concept to chemical mutagenesis, the view that, since DNA is DNA, mutational effects can be expected to be qualitatively similar in all organisms, the REC unit, and the view that mutation rates from c… more
Date: January 1, 1976
Creator: Russell, W.L.
Partner: UNT Libraries Government Documents Department
open access

Alteration of the retinoblastoma gene locus in radium-exposed individuals

Description: This study was performed to determine if the retinoblastoma suppressor gene was altered in individuals exposed to radium. We analyzed the Rb gene in 30 individuals, 17 of whom were exposed to radium either occupationally or iatrogenically. In the kidney DNA from four of nine radium-exposed individuals, the Rb gene was deleted. Three of these alterations in the Rb gene were internal deletions, which resulted in the absence of Rb mRNA accumulation. These results imply that the Rb gene is suscepti… more
Date: January 1, 1991
Creator: Hardwick, J.P.; Schlenker, R. & Huberman, E.
Partner: UNT Libraries Government Documents Department
open access

Genetic changes in Mammalian cells transformed by helium cells

Description: Midterm Syrian Hamster embryo (SHE) cells were employed to study high LET-radiation induced tumorigenesis. Normal SHE cells (secondary passage) were irradiated with accelerated helium ions at an incident energy of 22 MeV/u (9--10 keV/{mu}m). Transformed clones were isolated after growth in soft agar of cells obtained from the foci of the initial monolayer plated postirradiation. To study the progression process of malignant transformation, the transformed clones were followed by monolayer subcu… more
Date: November 1, 1990
Creator: Durante, M.; Grossi, G. (Naples Univ. (Italy). Dipt. di Scienze Fisiche); Yang, T.C. & Roots, R. (Lawrence Berkeley Lab., CA (USA))
Partner: UNT Libraries Government Documents Department
open access

Sunlight activation of shale-oil byproducts as measured by genotoxic effects in cultured Chinese hamster cells

Description: Activation of certain classes of promutagens/procarcinogens can be accomplished by exposure to various radiation sources. Retort processes currently in use in the production of shale oil generate significant quantities of process waters which contain a wide spectrum of uv-absorbing, organic material. Photoactivation of these waters with an artificial source of NUV results in genotoxic events in cultured mammalian cells. Since significant amounts (2 to 4%) of solar radiation reaching the earth's… more
Date: January 1, 1981
Creator: Strniste, G.F.; Chen, D.J. & Okinaka, R.T.
Partner: UNT Libraries Government Documents Department
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Cancer risks and neutron RBE's from Hiroshima and Nagasaki

Description: The new radiation dose estimates for Hiroshima and Nagasaki are radiobiologically examined for compatability with other human and experimental data. The new doses show certain improvements over the original T65 doses. However, they suggest for chronic granulocytic leukemia, total malignancies, and chromosome aberrations, at neutron doses of 1 rad, RBEs in excess of 100, higher than expected from other findings. This and other indications suggest that either there are unrecognized systematic pro… more
Date: March 25, 1982
Creator: Dobson, R.L. & Straume, T.
Partner: UNT Libraries Government Documents Department
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Tritium toxicity program in the Medical Department, Brookhaven National Laboratory

Description: It is possible to detect somatic, cytogenetic and genetic effects resulting from exposures at 33 to 100 times the mpc's for tritiated water (HTO). The reduction in bone marrow cells in animals maintaining normal total cellularity demonstrate both the presence of an effect at the primitive cell level as well as the animal's ability to compensate for this effect by recruiting stem cells from the G/sub 0/ resting state. This evidence of damage together with the observed cytogenetic changes leads o… more
Date: January 1, 1983
Creator: Carsten, A.L.
Partner: UNT Libraries Government Documents Department
open access

Estimates of radiation doses in tissue and organs and risk of excess cancer in the single-course radiotherapy patients treated for ankylosing spondylitis in England and Wales

Description: The estimates of absorbed doses of x rays and excess risk of cancer in bone marrow and heavily irradiated sites are extremely crude and are based on very limited data and on a number of assumptions. Some of these assumptions may later prove to be incorrect, but it is probable that they are correct to within a factor of 2. The excess cancer risk estimates calculated compare well with the most reliable epidemiological surveys thus far studied. This is particularly important for cancers of heavily… more
Date: February 1, 1982
Creator: Fabrikant, J.I. & Lyman, J.T.
Partner: UNT Libraries Government Documents Department
open access

Radiation-induced mesotheliomas in rats

Description: Mesotheliomas have been reported in rats that inhaled plutonium, but these tumors have not been extensively studied. To investigate a possible role for inhaled radionuclides in the induction of mesotheliomas, four life-span studies conducted at the Inhalation Toxicology Research Institute are reviewed. A total of 3076 F344 rats were exposed by inhalation to aerosols of {sup 239}PuO{sub 2}, mixed uranium-plutonium oxide, or {sup 144}CeO{sub 2}. Results showed that a low incidence of pleural meso… more
Date: January 1, 1990
Creator: Hahn, F. F.; Haley, P. J.; Hubbs, A. F.; Hoover, M. D. & Lundgren, D. L.
Partner: UNT Libraries Government Documents Department
open access

Respiratory tract carcinogenesis induced by radionuclides in the Syrian hamister

Description: Syrian hamsters were exposed to lung irradiation by various modalities that differed in degree of localization and the fraction of lung exposed. The animals were given alpha emitters under several exposure conditions: intratracheal (IT) instillation of /sup 210/Po and /sup 239/PuO/sub 2/-ZrO/sub 2/ microspheres; inhalation (INH) of /sup 238/ /sup 239/PuO/sub 2/-ZrO/sub 2/ particles; and/or intravenous (IV) injection of /sup 238/ /sup 239/PuO/sub 2/-ZrO/sub 2/ microspheres. Beta-emitting /sup 14… more
Date: January 1, 1979
Creator: Smith, D. M.; Thomas, R. G. & Anderson, E. C.
Partner: UNT Libraries Government Documents Department
open access

Comparison of protein patterns of xrs-5, a radiosensitive Chinese hamster ovary cell line, and CHO-K1, its radioresistant parent, using two-dimensional gel-electrophoresis

Description: X-ray sensitive strains of Chinese hamster ovary cell lines have been used to analyze radiation repair mechanisms. One cell line, xrs-5, has been shown to be very sensitive to ionizing radiation and radical forming chemical mutagens. This sensitivity is thought to be a result a mutation in the DNA double strand break (DSB) repair mechanism, and its characterization has been a goal of several repair mechanism studies. Using two-dimensional gel electrophoresis, we have detected a protein (MW appr… more
Date: January 1, 1991
Creator: Kramer, J.M. (Miami Univ., Oxford, OH (USA). Dept. of Zoology)
Partner: UNT Libraries Government Documents Department
open access

The influence of oscillating electromagnetic fields on membrane structure and function: Synthetic liposome and natural membrane bilayer systems with direct application to the controlled delivery of chemical agents

Description: Investigations have been conducted to determine if an imposed electromagnetic field can influence membrane transport, and ion and drug permeability in both synthetic and natural cell membrane systems. Microwave fields enhance accumulation of sodium in the lymphocyte and induce protein shedding at Tc. Microwaves also trigger membrane permeability of liposome systems under specific field exposure conditions. Sensitivity varies in a defined way in bilayers displaying a membrane structural phase tr… more
Date: September 1, 1989
Creator: Liburdy, R.P.; de Manincor, D. & Fingado, B.
Partner: UNT Libraries Government Documents Department
open access

Projected global health impacts from severe nuclear accidents: Conversion of projected doses to risks on a global scale: Experience from Chernobyl releases

Description: Best estimates of possible additional health effects were projected for the Northern Hemisphere: (1) over the next 50 years, up to 28 thousand radiation-induced fatal cancers, compared to an expected 600 million cancer deaths from natural or spontaneous causes; (2) over the next year, up to 700 additional cases of severe mental retardation, compared to a normal expectation of 340 thousand cases; and (3) in the first generation, up to 1.9 thousand radiation-induced genetic disorders, compared to… more
Date: January 1, 1987
Creator: Catlin, R. J.; Goldman, M. & Anspaugh, L. R.
Partner: UNT Libraries Government Documents Department
open access

Probabilistic methodology for estimating radiation-induced cancer risk

Description: The RICRAC computer code was developed at Oak Ridge National Laboratory to provide a versatile and convenient methodology for radiation risk assessment. The code allows as input essentially any dose pattern commonly encountered in risk assessments for either acute or chronic exposures, and it includes consideration of the age structure of the exposed population. Results produced by the analysis include the probability of one or more radiation-induced cancer deaths in a specified population, exp… more
Date: January 1, 1981
Creator: Dunning, D. E. Jr.; Leggett, R. W. & Williams, L. R.
Partner: UNT Libraries Government Documents Department
open access

Experimental radiation carcinogenesis: what have we learned

Description: The author reviews the need for animal experiments in development of a biological model for radioinduced carcinogenesis. He concludes they are vital for: (1) study of mechanisms; (2) establishment of generalizations; (3) elucidation of dose-response and time-dose relationships; and (4) determination of dose-distributions and their results, particularly for radionuclides. (PSB)
Date: January 1, 1980
Creator: Fry, R.J.M.
Partner: UNT Libraries Government Documents Department
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Effect of radiation quality and repair processes on the incidence of neoplastic transformation in vitro. [X radiation, mice]

Description: Studies of the effect of radiation dose fractionation on survival of mammalian cells show that x-ray dose fractionation results in a substantial increase in net survival due to the rapid repair of sublethal damage. For high LET radiations, however, the magnitude of any net survival increase is appreciably less and may be essentially absent. Thus the capacity of cells to repair sublethal damage is an important factor in considering the effect of fractionation radiation exposure in the potential … more
Date: January 1, 1979
Creator: Han, A. & Elkind, M. M.
Partner: UNT Libraries Government Documents Department
open access

Endogenous retrovirus and radiation-induced leukemia in the RMF mouse

Description: The induction of myeloid leukemia in irradiated RFM/Un mice has been associated with retrovirus infection. However, two characteristics of this strain complicate efforts to define the role of the virus. This strain possesses only one inducible host range class of endogenous virus and a unique gene, in addition to the Fv-1/sup n/ locus, which specifically restricts exogenous infection by endogenous viruses. These characteristics possibly account for absence of recombinant viruses in this strain,… more
Date: January 1, 1982
Creator: Tennant, R. W.; Boone, L. R.; Lalley, P. & Yang, W. K.
Partner: UNT Libraries Government Documents Department
open access

Dominant-lethal mutations and heritable translocations in mice

Description: Chromosome aberrations are a major component of radiation or chemically induced genetic damage in mammalian germ cells. The types of aberration produced are dependent upon the mutagen used and the germ-cell stage treated. For example, in male meiotic and postmeiotic germ cells certain alkylating chemicals induce both dominant-lethal mutations and heritable translocations while others induce primarily dominant-lethal mutations. Production of these two endpoints appears to be determined by the st… more
Date: January 1, 1983
Creator: Generoso, W.M.
Partner: UNT Libraries Government Documents Department
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