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Low-level x-irradiation of the brain during development morphological, physiological, and behavioral consequences. Final report, September 1, 1976--August 31, 1977

Description: Morphological research was continued in the following areas: glial recovery patterns in the rat corpus callosum after x-irradiation during infancy; the prenatal development of the deep nuclei and cortex of the cerebellum; the prenatal development of the inferior olive, pontine gray and the precerebellar reticular nuclei; and the postnatal development of the olfactory bulb. In these studies autoradiography and x-irradiation were among the experimental techniques utilized. The behavioral studies,… more
Date: January 1, 1977
Creator: Altman, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Delayed radiation injury of gut-exposed and gut-shielded mice. II. The decrement in life span

Description: Two mouse strains (RF/J and C57B1/6J) were exposed to x-ray doses totaling 400, 800, and 1200 rad. Total doses were given in 200-rad fractions at 7-day intervals to the whole body, gut only, or bone tissue with the gut shielded. Animals were anesthetized during exposure. Two control groups were used. A sham control group was anesthetized but not exposed to x rays, and another control group received neither anesthesia nor x-radiation. All mice were retained in a standard laboratory environment f… more
Date: January 1, 1978
Creator: Spalding, J.F.; Archuleta, R.F. & Prine, J.R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Late biological effects of ionizing radiation as influenced by dose, dose rate, age at exposure, and genetic sensitivity to neoplastic transformation. [Gamma radiation, mice]

Description: A most comprehensive investigation is in progress at the Los Alamos Scientific Laboratory to study the late biological effects of whole-body exposure to gamma irradiation as they may be influenced by total dose, dose rate, age at exposure, and genetic background. Strain C57B1/6J mice of four age groups (newborn, 2, 6, and 15 months) were given five doses (20, 60, 180, 540, and 1620 rad) of gamma rays, with each dose being delivered at six dose rates (0.7, 2.1, 6.3, 18.9, 56.7 rad/day and 25 rad… more
Date: January 1, 1978
Creator: Spalding, J.F.; Prine, J.R. & Tietjen, G.L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Spermatogonial stem cell renewal following irradiation

Description: The spermatogonial cell renewal system can maintain function and a steady level of cell population for relatively long periods of continuous low-level irradiation indicating that there does not appear to be a serious accumulation, over many generations, of damage affecting proliferation. Provided the dose-rate is quite low, there is an effective selective removal of damaged cells with almost complete repair of cellular nonlethal damage. At dose-rates greater than 2 rad/day, spermatogonia are ve… more
Date: May 1, 1979
Creator: Fabrikant, Jacob I.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Metabolism and biological effects of alpha-emitting radionuclides

Description: The emphasis of much of the current and planned research on the toxicity of alpha-emitting radionuclides is directed toward the complexities of actual and potential conditions of occupational environmental exposures of human beings. These, as well as the more limited studies on mechanisms of biological transport and effects, should increase our ability to predict health risks more accurately and to deal more confidently with human exposures, if and when they occur.
Date: May 1, 1979
Creator: Bair, W. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Study on the induction of thyroid tumors in rats using x irradiation in conjunction with a goitrogen. [1 methyl--2 mercaptoimidazole (methimazole)]

Description: The influence of acute localized thyroid x irradiation and chronic goitrogen administration, separately or combined, on thyroid tumor formation in mature female rats was studied. In the first experiment, the radiation doses were 0, 80, 160, 320, or 640 rads, and the dosages of goitrogen were 0, 4, or 40 parts per million (ppM) of 1 methyl - 2 mercaptoimidazole (MMI). The incidence of rats with thyroid tumors in any treated group receiving 0 or 4 ppM MMI was not significantly greater than the in… more
Date: January 1, 1979
Creator: Mahler, P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Relationship between unscheduled DNA synthesis and mutation induction in male mice

Description: Unscheduled DNA synthesis (UDS) induced in the germ cells of male mice by chemical and physical agents can be studied in vivo by making use of the timing of spermatogenesis and spermiogenesis. In meiotic and post-meiotic germ-cell stages UDS occurs from leptotene through mid-spermatid stages but is not detected in later stages. No consistent correlation has been seen between the occurrence of UDS in the germ cells and reduced dominant-lethal frequencies or reduced specific-locus mutation freque… more
Date: January 1, 1979
Creator: Sega, G. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Radiation-induced dominant skeletal mutations in mice: mutation rate, characteristics, and usefulness in estimating genetic hazard to humans from radiation

Description: The work discussed in this paper represents a major advance in the difficult task of trying to estimate the effects that an increase in mutation frequency would have on human health. Male mice were bred to three females prior to being killed and skeleton studies made. Guidelines were instituted for checking progeny mutations. Surprising results showed a mutation frequency of 1.4% per gamete where none would have been expected. It is now clear that mice can be greatly deformed without showing ex… more
Date: May 1, 1979
Creator: Selby, P. B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Repair in fertilized eggs of mice and its role in the production of chromosomal aberrations. [Comparison of the effects of the chemical mutagens EMS, IMS, and TEM with the physical mutagen x rays]

Description: The fertilized egg may influence the yield of dominant-lethal mutations produced from chemical treatment of male postmeiotic germ cells to a small or large extent depending upon the mutagen used and the competence of the egg to repair the premutational lesions induced. The strain of females has small influence on the yield of dominant-lethal mutations induced by TEM or EMS in spermatids and spermatozoa. On the contrary, it has large influence in the case of IMS. In addition to this difference, … more
Date: January 1, 1979
Creator: Generoso, W M
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Radiation- and drug-induced DNA repair in mammalian oocytes and embryos

Description: A review of studies showing ultraviolet- or drug-induced unscheduled DNA synthesis in mammalian oocytes and embryos suggests that the female gamete has an excision repair capacity from the earliest stages of oocyte growth. The oocyte's demonstrable excision repair capacity decreases at the time of meiotic maturation for unknown reasons, but the fully mature oocyte maintans a repair capacity, in contrast to the mature sperm, and contributes this to the zygote. Early embryo cells maintain re… more
Date: January 1, 1979
Creator: Pedersen, R A & Brandriff, B
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Carcinogenesis in mice after low doses and dose rates

Description: The results from the experimental systems reported here indicate that the dose-response curves for tumor induction in various tissues cannot be described by a single model. Furthermore, although the understanding of the mechanisms involved in different systems is incomplete, it is clear that very different mechanisms for induction are involved. For some tumors the mechanism of carcinogenesis may be mainly a result of direct effects on the target cell, perhaps involving one or more mutations. Wh… more
Date: January 1, 1979
Creator: Ullrich, R.L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Possibilities and problems in uv radiation carcinogenesis experiments

Description: Experiments were designed to solve problems in dose-response relationships in uv-induced carcinogenesis. Two strains of hairless mice were exposed to 300 to 400 nm, 320 to 400 nm, and 365 nm wavelength emissions following exposure to 8-methoxy-psoralen; various fractionation regimes were used. Results showed that the number of psoralen-DNA crosslinks per cell increased linearly with dose. The importance of wavelength in the initiation and the expression of tumors is emphasized. (HLW)
Date: January 1, 1978
Creator: Fry, R.J.M.; Ley, R.D. & Grube, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Cellular proliferation and regeneration following tissue damage. Progress report. [X radiation; rabbit lenses]

Description: Studies were conducted on the following research projects: effects of x radiation on rabbit lenses; DNA synthesis and mitosis in cultured lenses; serum dependency and actinomycin D sensitivity; changes in ultrastructure; injury-induced growth of vascular endothelium; corneal neovascularization following injury; and human cataractous lenses. (HLW)
Date: January 1, 1977
Creator: Harding, C.V.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Mutational repair in mammals and its bearing on risk assessment

Description: Most of the genetic risk from radiation in humans will involve germ cell stages that are of long duration, namely, the spermatogonial stem cells in the male and the oocytes in the female. Mutagenic studies in the mouse that are concerned with risk assessment have, therefore, concentrated on these stages. The first evidence that some repair of mutational damage could occur came from investigations with the specific-locus method in the mouse in which it was shown that when a given dose of radiati… more
Date: January 1, 1977
Creator: Russell, W.L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Effects of ionizing radiation on the light sensing elements of the retina. [Structural and physiological effects of carbon, helium, and neon ions on rods and cones of salamanders and mice]

Description: This investigation was undertaken to quantitate possible morphological and physiological effects of particles of high linear energy transfer on the retina, in comparison with x-ray effects. The particles used were accelerated atomic nuclei of helium, carbon, and neon at kinetic energies of several hundred MeV/nucleon. For morphological studies, scanning and transmission electron microscopy and light microscopy were used. Physiological studies consisted of autoradiographic data of the rate of in… more
Date: July 1, 1978
Creator: Malachowski, M.J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Effects of a radiation-induced. cap alpha. -thalassemia on the production of multiple forms of hemoglobins in fetal mice

Description: Embryonic hemoglobins in ..cap alpha..-thalassemic heterozygotes and normal fetuses were compared to study the effects of the deficient ..cap alpha.. chain on the synthesis of hemoglobins in the nucleated embryonic erythrocytes derived from the fetal yolk sac. Acrylamide gel electrophoresis showed that less hemoglobin Ell (..cap alpha../sub 2/y/sub 2/) was formed in ..cap alpha..-thalassemic heterozygotes between 12/sup 1///sub 2/ and 14/sup 1///sub 2/ days of gestation. Quantitation of in vitr… more
Date: January 1, 1978
Creator: Popp, R. A.; Bradshaw, B. S. & Hirsch, G. P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Basic study on the role of thymus in hemopoietic differentiation

Description: Marrow, after in vitro treatment with either ..cap alpha.. Thy 1.2 or nonimmune serum and complement, was transplanted to separate groups of lethally irradiated isogenic mice. Mice of several different genotypes were used in 12 studies. Macroscopic spleen colony numbers were similar in the two groups, but differences were found when spleens were examined microscopically. The most striking and consistent finding was a decrease in granulopoietic colonies in recipients of ..cap alpha.. Thy 1.2 tre… more
Date: January 1, 1977
Creator: Goodman, J W; Basford, N L & Shinpock, S G
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Age-dependent radiosensitivity of mouse oocytes

Description: It has been shown that there are three distinct phases of radiosensitivity in oocytes of prepubertal mice: a period of rapidly increasing sensitivity between 0 and 4 days of age; a period of consistent, high sensitivity between 5 and 18 days of age; and a period of decreasing sensitivity from 19 to at least 21 days of age. Two distinct phases have been demonstrated for the rate of population decline of the oocytes of primary follicles: an initial period of rapid loss from 0 to 4 days of age; an… more
Date: June 8, 1976
Creator: Koehler, C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Genetic effects of radiation. [Extrapolation of mouse data to man]

Description: Data are reviewed from studies on the genetic effects of x radiation in mice and the extrapolation of the findings for estimating genetic hazards in man is discussed. Data are included on the frequency of mutation induction following acute or chronic irradiation of male or female mice at various doses and dose rates.
Date: January 1, 1976
Creator: Selby, P. B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Aging and DNA repair capability. [Review]

Description: A review of the literature on DNA repair processes in relation to aging is presented under the following headings: DNA repair processes; age-related occurrence of unrepaired DNA lesions; DNA repair capability as a function of age; tissue-specific DNA repair capability; acceleration of the aging process by exposure to DNA damaging agents; human genetic syndromes; and longevity and DNA repair processes. (HLW)
Date: January 1, 1977
Creator: Tice, Raymond R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Effects of whole-body. gamma. -irradiation on the biosynthesis of certain serum proteins. Final report, November 29, 1967--June 30, 1976. [Rats]

Description: Whole-body exposure of rats to ionizing radiations yielded an increased incorporation of labeled amino acids into serum albumin in in vivo studies suggesting a stimulation of biosynthesis. Actually this may have been caused by an elevated hepatic transport of labeled amino acids (see below). A suppressed biosynthesis of albumin was observed when the experiments were performed in vitro using liver microsomes. Impaired biosynthesis appeared to be caused by a reduced mRNA production. Irradiation s… more
Date: June 30, 1976
Creator: Neuhaus, O. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Acquired immunologic tolerance in chimeras and histocompatibility factors in cattle and their relationship to those in humans. Final report. [Gamma radiation]

Description: During the course of this project we have studied 35 pairs of chimeric cattle twins. It is now clear that fractionated doses of whole-body /sup 60/Co irradiation can cause marked shifts in the proportions of the two erythrocyte populations that make up the chimeric mixture. However, it has not been possible to eliminate one of the two cell types and thus abrogate the acquired immunologic tolerance. The results of our extensive skin-grafting experiments are remarkable because they show that a ch… more
Date: March 1, 1976
Creator: Stone, W. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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