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Effects of Low Levels of X-Rays and Irradiation from C14 and H3 on Cell Population Kinetics in the Root Tip of Tradescantia

Description: Reciprocal labelling in double-labelling experiments with H3- and C14- thymidine showed that when H3- thymidine (1μc/ml for 0.5 hr) was given first in the labelling sequence followed by a 4 hr interval before the C14- thymidine treatment, that passage of cells into and out of DNA synthesis was normal. When C14 was first in the sequence, the rate at which cells entered DNA synthesis was decreased. This was attributed to a radiation effect produced by the β-rays from the C14. The rate at which ce… more
Date: March 25, 1963
Creator: Wimber, Donald E.
Partner: UNT Libraries Government Documents Department
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Mechanisms of the Bystander Effect

Description: Generations of students in radiation biology have been taught that heritable biological damage requires direct damage to DNA. We now know that this is not true. The Bystander Effect is the name given to the phenomenon whereby biological effects are observed in cells that are not themselves traversed by a charged particle, but are in close proximity to cells that are. Several research groups have convincingly demonstrated a bystander effect for alpha particle, which are heavy and high LET, becau… more
Date: July 15, 2008
Creator: Hall, Eric J.
Partner: UNT Libraries Government Documents Department
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Possibilities and Limitations in the use of Tritiated Thymidine for in Vivo Cytokinetic Studies on Lymphoreticular Tissue

Description: Tritiated thymidine (H3TDR), a specific precursor of deoxyribonucleic acid (DNA), has proved to be a valuable tool in the study of in vivo cellular kinetics. Various methods of analysis have been used in autoradiographic investigations of proliferative patterns and time parameters in different cell lines.
Date: February 1, 1963
Creator: Cottier, H.; Odartchenko, N.; Feinendegen, L. E. & Bond, V. P.
Partner: UNT Libraries Government Documents Department
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Reutilization of DNA-Thymine, and Conversion of RNA-Pyrimidines for DNA-Thymine, in Normal Rat Bone Marrow Studies with Tritiated Nucleosides

Description: If one injects into an animal H3-thymidine, 50% of it is incorporated into deoxyribonucleic acid (DNA), within approximately 30 to 45 minutes, while the rest is catabolized. A storage of H3-thymidine for later incorporation into DNA does not occur, on the basis of available evidence. Once incorporated, the label remains bound to DNA until cell death and no unequivocal evidence has as yet been presented to indicate metabolic renewal or intracellular turnover of the DNA molecule. The loss of labe… more
Date: November 13, 1963
Creator: Feinendegen, L. E.; Bond, V. P.; Cronkite, E. P. & Hughes, W. L.
Partner: UNT Libraries Government Documents Department
open access

Cell Population Kinetics of an Osteogenetic Tissue, II

Description: A study of the cell kinetics on the actively growing periosteal surface of the femur of rabbits ages two weeks has been continues. A single injection of tritiated thymidine was given and the rabbits killed from one hour to four days after injection. The grain count spectra of the different cell types, pre-osteoblast, osteoblast and osteocyte, have been compared at different times after injection. The results showed evidence for the uptake of thymidine in nuclei which is not associated with cell… more
Date: March 12, 1963
Creator: Owen, Maureen & Pherson, Sheila Mac
Partner: UNT Libraries Government Documents Department
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The Use of Tritiated Thymidine in the Study of Tissue Activation During Germination in Zea Mays L.

Description: The transition from dormancy to growth in plant seeds has been the topic of many biological studies (1,2). Of particular interest to the radiobiologist are the dramatic changes in radiosensitivity occurring soon after the soaking of the seeds (3). These changes are thought to be associated with the commencement of proliferative activity. The recently developed method of labeling DNA with tritiated thymidine allows analysis of proliferative activity in greater detail than was heretofore possible… more
Date: February 1, 1963
Creator: Stein, O. L.
Partner: UNT Libraries Government Documents Department
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Kinetics of Erythrocytic Precursor Proliferations in Dog

Description: In a previous publication, the development of labeled cells (considered capable of division) after a single injection of thymidine, into mitosis and into other morphological stages corresponding to initially non-labeling nucleated erythrocytic precursors led to an evaluation of time parameters for these groups. These observations are extended in the present communication by using multiple injections of tritiated thymidine, compared to a single injection. The data presented confirm the time para… more
Date: 1962
Creator: Odartchenko, N.; Bond, V. P. & Feinendegen, L. E.
Partner: UNT Libraries Government Documents Department
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Evaluation of Mitotic Time in Vivo, Using Tritiated Thymidine as a Cell Marker: Successive Labeling with Time of Separate MItotic Phases

Description: The duration of mitosis is of great importance in an evaluation of growth rates in proliferating somatic tissues, since calculations are based on observations of mitotic activity, and therefore final results are directly proportional to an assumed value for mitotic time. This duration cannot be measured directly in vivo at a tissue level, since the mode of distribution of the single cell value is not known. This difficulty is not overcome in extrapolations from in vitro measurements. Also it is… more
Date: October 15, 1963
Creator: Odartchenko, N.; Cottier, H.; Feinendegen, L. E. & Bond, V. P.
Partner: UNT Libraries Government Documents Department
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The Simultaneous Labeling of Cells in Different Segments of the Mitotic Cycle with Tritiated Thymidine and Colchicine and the Effect of Colchicine on Thymidine Uptake

Description: Treatment of Pisum root meristems with nutrient solutions containing tritiated thymidine (H3-T) and colchicine simultaneously labeled cells in two different segments of the mitotic cycle. Tracings of the serial progression of these differently labeled cells through mitosis resembled sine-cosine curves. When the labeled cells are in interphase the sign of the curves is negative, when they are in mitosis the sign is positive. The concept of the mitotic cycle in terms of trigonometric functions wa… more
Date: October 14, 1963
Creator: Van't Hof, J. & Ying, Huei-Kuen
Partner: UNT Libraries Government Documents Department
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Mechanisms for radiation damage in DNA

Description: A comprehensive report is provided of the author`s research since 1986 on radiolysis of DNA as well as current state of knowledge in this area. In particular study areas such as the influence of hydration on the absolute yield of primary ionic free radicals in irradiated DNA at 77K, Ab Initio molecular orbital calculations of DNA base pairs and their radical ions, and radiation-induced DNA damage as a function of hydration are discussed.
Date: November 1, 1994
Creator: Sevilla, M. D.
Partner: UNT Libraries Government Documents Department
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Elimination of Phases the Life Cycle of Leukemic Cells From in Vivo Labeling in Human Beings With Tritiated Thymidine

Description: Our earlier in vitro studies have suggested that malignant tumors may not produce new cells more rapidly than normal cells are produced in the "steady state" equilibrium. Obviously tumors of all typed represent a diversion from "steady state" production with a net gain in mass of tissue. However, the increase in mass is not necessarily constant and may fluctuate in the natural history of the disorder. DNA labeling with tritiated thymidine had made it possible to characterize normal "steady stat… more
Date: February 1, 1963
Creator: Killmann, S. A.; Cronkite, E. P.; Robertson, J. S.; Fliedner, T. M. & Bond, V. P.
Partner: UNT Libraries Government Documents Department
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The Effect of Tritiated Thymidine on the Morphogenesis of Lateral Roots

Description: Most studies of the effect of radiation upon plant development utilized external sources of irradiation. Where radioactive isotopes were used these were primarily applied in metabolic or cytological studies. The effects of these isotopes are similar to those produced by external irradiation, modified by such phenomena as specific localization, timing of irradiation, modified by such phenomena as specific localization, timing of irradiation, etc. The advent of tritium as a means of irradiation o… more
Date: unknown
Creator: Stein, O. L. & Quastler, H.
Partner: UNT Libraries Government Documents Department
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AN ANALYSIS OF H$sup 3$-THYMIDINE DISTRIBUTION THROUGHOUT THE SHOOT APICAL MERISTEM OF ARABIDOPSIS THALIANA (L.) HEYNH

Description: Sequential autoradiographed sections through the shoot apical meristem of Arabidopsis thaliana treated for six hours with a solution of H/sup 3/- thymidine in combination with 0.1% Tween 20 and dilute mineral solution reveal a differential pattern of labeling, indicative of differential rates of DNA synthesis. This pattern corresponds to the histological zonation of the apex and reveals a sub-apical block of cells in which the amount of incorporation is significantly lower than in the adjacent … more
Date: January 1, 1962
Creator: Brown, J. A. M.; Miksche, J. P. & Smith, H. H.
Partner: UNT Libraries Government Documents Department
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The Fate of Transfused H3 Thymidine Labeled Bone Marrow Cells in Irradiated Recipients

Description: It has been established by chromosome marker studies, histochemical, immunological, and cytological methods that the hemopoietic tissues of animals exposed to lethal doses of whole-body irradiation can be repopulated by transfused autologous, homologous or heterologous bone marrow cells. However, the morphology of the cell responsible for the regeneration of hematopoietic activity in the various hemopoietic organs has not been identified. It has been shown that the bone marrow contains the cell… more
Date: February 1, 1963
Creator: Fliedner, T. M.; Thomas, E. D.; Meyer, L. M. & Cronkite, E. P.
Partner: UNT Libraries Government Documents Department
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Differential roles of XRCC2 in S-phase RAD51 focus formation induced by DNA replication inhibitors

Description: RAD51 proteins accumulate in discrete nuclear foci in response to DNA damage. Previous studies demonstrated that human RAD51 paralogs (RAD51B, RAD51C, RAD51D, XRCC2 and XRCC3) are essential for the assembly of RAD51 foci induced by ionizing radiation and cross-linking agents. Here we report that XRCC2 also plays important roles in RAD51 focus formation induced by replication arrest during S-phase of cell cycle. In wild-type hamster V79 cells treated with hydroxyurea (HU), RAD51 protein form pun… more
Date: May 14, 2004
Creator: Lim, C & Liu, N
Partner: UNT Libraries Government Documents Department
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DEVELOPMENT OF IMPROVED ANAEROBIC GROWTH OF BACILLUS MOJAVENSIS STRAIN JF-2 FOR THE PURPOSE OF IMPROVED ANAEROBIC BIOSURFACTANT PRODUCTION FOR ENHANCED OIL RECOVERY

Description: Our work focuses on the use of microorganisms to recover petroleum hydrocarbons that remain entrapped after current recovery technologies reach their economic limit. Capillary forces between the hydrocarbon and aqueous phases are largely responsible for trapping the hydrocarbons in the pores of the rock and large reductions in the interfacial tension between the hydrocarbon and aqueous phases are needed for hydrocarbon mobilization (1-3, 10, 11). Microorganisms produce a variety of biosurfactan… more
Date: May 31, 2004
Creator: McInerney, M.J.; Folmsbee, M. & Nagle, D.
Partner: UNT Libraries Government Documents Department
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Processing of DNA damage after exposure to a single dose of fission spectrum neutrons takes 40 hours to complete

Description: We have examined the time course over a period of days of repair of chromosomal single-strand breaks (SSB) induced by a single dose of JANUS fission-spectrum neutrons in the DNA of human P3 epithelial teratocarcinoma cells. When the cells are allowed a period of repair incubation the breaks are totally sealed by 7 hours. But then following these initial repair the DNA is dismantled as evidenced by the reappearance of SSBs. This secondary breakage is almost as extensive as that caused by the ori… more
Date: November 1, 1996
Creator: Peak, J.G. & Peak, M.J.
Partner: UNT Libraries Government Documents Department
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Adult Human Pancreatic Islet Beta-Cells Display Limited Turnover and Long Lifespan as Determined by In-Vivo Thymidine Analog Incorporation and Radiocarbon Dating

Description: Diabetes mellitus results from an absolute or relative deficiency of insulin producing pancreatic beta-cells. The adult human beta-cell's turnover rate remains unknown. We employed novel techniques to examine adult human islet beta-cell turnover and longevity in vivo. Subjects enrolled in NIH clinical trials received thymidine analogues [iododeoxyuridine (IdU) or bromodeoxyuridine (BrdU)] 8-days to 4-years prior to death. Archival autopsy samples from ten patients (aged 17-74 years) were employ… more
Date: March 15, 2010
Creator: Perl, S.; Kushner, J. A.; Buchholz, B. A.; Meeker, A. K.; Stein, G. M.; Hsieh, M. et al.
Partner: UNT Libraries Government Documents Department
open access

Results of The Analysis of The Blood Beryllium Lymphocyte Proliferation Test Data From The Oak Ridge Y-12 Study

Description: The potential hazards from exposure to beryllium or beryllium compounds in the workplace were first reported in the 1930s. The tritiated thymidine beryllium lymphocyte proliferation test (BeLPT) is an in vitro blood test that is widely used to screen beryllium exposed workers in the nuclear industry for sensitivity to beryllium. Newman [18] has discussed the clinical significance of the BeLPT and described a standard protocol that was developed in the late 1980s. Cell proliferation is measured … more
Date: December 18, 2001
Creator: Frome, EL
Partner: UNT Libraries Government Documents Department
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