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in subjects: "In Vitro"

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Effect of LET and microdistribution of radiation on the transformation in vitro and in vivo. Comprehensive progress report

Work has involved the following three areas: (1) an investigation of the mechanisms of radiation carcinogenesis by studying the events involved in the process of malignant transformation of mouse 10 T-1/2 cells; (2) an investigation of the effects of promoting agents on radiation-induced transformation in vitro; and (3) an investigation of the induction of transformation by internally emitting radionuclides incorporated into cellular DNA. The latter area has been extended to include studies of … more

Date: September 1, 1983

Creator: Little, J. B.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

QNS measurements on water in biological and model systems

Results are presented on the quasi-elastic spectra of 0.95 THz neutrons scattered from pure water, a 20% agarose gel and cysts of the brine shrimp (Artemia) of hydration 1.2 gms H/sub 2/O per gm of dry solids. The lines are interpreted with a two-component model in which the hydration water scatters elastically and the free water is described by a jump-diffusion correlation function. The results for the line widths GAMMA(Q/sup 2/) are in good agreement with previous measurements for the water s… more

Date: January 1, 1981

Creator: Trantham, E. C.; Rorschach, H. E.; Clegg, J. C.; Hazlewood, C. F. & Nicklow, R. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Study of the radiation effects on nucleic acids and related compounds. Annual progress report, August 15, 1974--August 14, 1975. [X radiation, hamster cells, Haemophilus influenzae]

Interest is being centered on the chemical and physical nature of radiation-induced lesions to nucleic acids and their components. These investigations have revealed the enormous complexity of chemical events in these systems and the possible degradation of nucleic acids by strand breakage. Therefore, work in the ionizing radiation of DNA and its components has proceeded along a dual course. For chemical studies, our prime concern is the stepwise isolation and identification of the radiation pr… more

Date: January 1, 1975

Creator: Wang, S. Y.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Repair of DNA treated with. gamma. -irradiation and chemical carcinogens. Progress report, June 1, 1975--January 31, 1976. [MMS, methylnitrosourea, 7-bromomethyl-12-methylbenz(a)-anthracene, Escherichia coli]

Enzymatic mechanisms of DNA repair are under investigation. From E. coli an endonuclease active on apurinic acid has been separated from endonuclease II active on DNA treated with methylmethane sulfonate, methylnitrosourea, 7-bromomethyl-12-methylbenz(a)anthracene and ..gamma..-irradiation. Mutants have been identified for each enzyme. The purification of both enzymes is proceeding and the mechanism of action of endonuclease II which has both an N-glycosidase and a phosphodiester hydrolase acti… more

Date: February 1, 1976

Creator: Goldthwait, D. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Molecular basis for the mutagenic and lethal effects of ultraviolet irradiation. Progress report, December 1, 1977--November 30, 1978. [Micrococcus luteus, Escherichia coli]

Our earlier work on the chemical basis of mutagenesis led to certain chemical generalities necessary to explain how certain mutagens such as UV light and hydroxylamine functioned in information transfer systems (replicative, transcriptive and translational). When such modifications were applied to biologically active DNA in a controlled manner biological expression was non-stoichiometric because much of the damage was removed from the DNA by repair systems. Our efforts were then directed to the… more

Date: July 1978

Creator: Grossman, L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Low angle neutron data acquisition system for molecular biology

The low angle spectrometer system utilizing a 2-dimensional position sensitive counter was designed to accommodate a variety of experiments in molecular biology requiring good low angle resolution. Biological structures requiring low angle analysis techniques fall into two groups: non-ordered systems (proteins or protein complexes in solution) and ordered systems with large spacings like muscle, collagen, and membranes. For structural investigations into such systems, data are ideally needed to… more

Date: January 1, 1977

Creator: Schoenborn, B. P.; Alberi, J.; Saxena, A. M. & Fisher, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Chemical cytotoxicity: a cancer promoter

Study of available data from radiation- and chemically-induced carcinogenesis experiments has indicated a linear relationship between cancer incidence and cytotoxicity for a number of different systems. We hypothesize that the cytotoxic activity (individually or collectively) of a number of chemical carcinogens may act as a promotional stimulus, to generate an enlarging tumor mass from a small population of altered cells. A model is developed from which cancer risk of various chemicals can be e… more

Date: January 1, 1978

Creator: Griffin, G. D.; Jones, T. D. & Walsh, P. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Polycyclic aromatic hydrocarbon-protein interactions. Progress report, March 1, 1979-February 28, 1980

As bovine serum albumin (BSA) undergoes acid- or base-induced conformational changes, the binding of benzo(a)pyrene (BaP) to BSA, as well as the type II uv fluorescence (380 nm) due to pyrene-like oxidation products, increases. The presence of fatty acids also enhances the binding of BaP to BSA at neutral pH, whereas the visible fluorescence of BaP is effectively quenched by fatty acids. L-Tryptophan, which is specifically bound to BSA, enhances the BaP binding and particularly the formation of… more

Date: October 1, 1979

Creator: Fujimori, E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Mechanisms for radiation damage in DNA. Progress report, August 1, 1976--October 31, 1977

In this project we have proposed mechanisms for radiation damage to DNA constituents and DNA, and have detailed a series of experiments utilizing electron spin resonance spectrometry to test the proposed mechanisms. In this past year investigations were completed on reactions of the ..pi..-cations of thymidine TMP and 1-methylthymine, charge transfer in aromatic peptide ..pi..-cation radicals, and electron reactions with amino acid anhydrides. A study in which we have made significant progress … more

Date: July 1, 1977

Creator: Sevilla, M. D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Molecular events basic to cellular radiation response. Progress report

Studies on regulation of gene expression included research projects on turnover of ribosomal RNA, ribonuclease-resistant oligonucleotides, and reutilization of oligonucleotides. Studies on radiation effects on RNA included research projects on radioinduced strand breaks in RNA and radioinduced alterations in RNA nucleotides. Effects of vasopression on radiosensitivity were studied. Studies on amino acid-nucleic acid interactions included research projects on synthesis and spectroscopic analysis… more

Date: January 1, 1976

Creator: Kolodny, G. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Mechanisms for radiation damage in DNA constituents and DNA

The initial effects of all forms of ionizing radiation on DNA are the production of positive ions, negative ions, and excited states of the DNA bases. These species may later react to produce biologically significant damage. The reactions of ion radicals produced individually in DNA bases are reviewed. In this discussion emphasis is placed on the initial events immediately after ionization, i.e., the fate of the electron and positive hole in irradiated DNA. A number of techniques which have bee… more

Date: January 1, 1977

Creator: Sevilla, M. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Maximum likelihood estimation for cytogenetic dose-response curves

In vitro dose-response curves are used to describe the relation between the yield of dicentric chromosome aberrations and radiation dose for human lymphocytes. The dicentric yields follow the Poisson distribution, and the expected yield depends on both the magnitude and the temporal distribution of the dose for low LET radiation. A general dose-response model that describes this relation has been obtained by Kellerer and Rossi using the theory of dual radiation action. The yield of elementary l… more

Date: October 1, 1983

Creator: Frome, E.L & DuFrain, R.J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Hematopoietic cell crisis: An early stage of evolving myeloid leukemia following radiation exposure

Under select radiological conditions, chronic radiation exposure elicits a high incidence of myeloproliferative disease, principally myeloid leukemia (ML), in beagles. Previously we demonstrated that for full ML expression, a four-stage preclinical sequence is required, namely (1) suppression, (2) recovery, (3) accommodation, and (4) preleukemic transition. Within this pathological sequence, a critical early event has been identified as the acquisition of radioresistance by hematopoietic progen… more

Date: January 1, 1990

Creator: Seed, T.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Study of the effects of radiation of nucleic acids and related compounds. Progress report, August 15, 1975--August 14, 1976

Ionizing radiation produces genetic effects in biological systems. Since genetic effects are usually the result of modifications of DNA or sometimes of RNA, interest is being centered on the chemical and physical nature of radiation-induced lesions to nucleic acids and their components. These investigations have revealed the enormous complexity of chemical events and the possible degradation of nucleic acids by strand breakage. Therefore, work in the ionization radiation of nucleic acids has pr… more

Date: April 1, 1976

Creator: Wang, S. Y.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Reaction mechanisms in the radiolysis of peptides, polypeptides and proteins

The purpose of this review is to bring together and to correlate the wide variety of experimental studies that provide information on the reaction products and reaction mechanisms involved in the radiolysis of peptides, polypeptides and proteins (including chromosomal proteins) in both aqueous and solid-state systems. The comparative radiation chemistry of these systems is developed in terms of specific reactions of the peptide main-chain and the aliphatic, aromatic-unsaturated and sulfur-conta… more

Date: January 1, 1985

Creator: Garrison, Warren M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Chlorophyll photochemistry in condensed media: triplet state quenching and electron transfer to quinone in cellulose acetate films

Chlorophyll a was incorporated into cellulose acetate films and the triplet decay and electron transfer to p-benzoquinone in aqueous solution was studied using laser flash photolysis and ESR. The triplet was found to decay by first order kinetics with the same rate constant regardless of chlorophyll concentration, but the yield was concentration dependent. This is due to quenching at the ground and/or singlet state levels. In the presence of quinone, the triplet is quenched and, when the quinon… more

Date: January 1, 1979

Creator: Cheddar, G.; Castelli, F. & Tollin, G.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

[Report of Foreign Travel: International Workshop on Radioiodinated Free Fatty Acids, Amsterdam]

The traveler participated in the Second International Workshop on Radioiodinated Free Fatty Acids in Amsterdam, The Netherlands where he presented an invited paper describing the pioneering work at the Oak Ridge National Laboratory (ORNL) involving the design, development and testing of new radioiodinated methyl-branched fatty acids for evaluation of heart disease. He also chaired a technical session on the testing of new agents in various in vitro and in vivo systems. He also visited the Insti… more

Date: December 11, 1987

Creator: Knapp, Furn F., Jr.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Boronated monoclonal antibody conjugates for neutron capture therapy

This paper describes the effectiveness of /sup 10/B-labeled monoclonal antibodies against Colo-38 human melanoma in vitro. The authors obtained high boron to antibody ratios while maintaining antibody activity by using dextran intermediate carriers to link /sup 10/B to the antibody. They developed a double cell quasi-competitive binding bioassay to minimize the effects of nonspecific binding of boronated complexes to cells. 1 fig., 2 tabs.

Date: January 1, 1986

Creator: Borg, D.C.; Elmore, J.J. Jr. & Ferrone, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Effect of light on respiration and development of photosynthetic cells. Progress report, September 1, 1977--August 31, 1978

The biophotolysis of water by photosynthetic cells resulting in the formation of hydrogen gas is of prime concern. That algal cells require both photosystems to complete this process is established. That a reduced carbon source can be photoxidized to release hydrogen and carbon dioxide has been proven. On the other hand, whether water is split to hydrogen and oxygen by the intact cell adapted to a hydrogen metabolism is an open question. A reconstituted preparation of higher plants can split wa… more

Date: August 31, 1977

Creator: Gibbs, M

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Effects of phenol on ATPase activities in crude gill homogenates of rainbow trout (Salmo gairdneri Richardson)

The ATPase specific activities from crude gill homogenates of rainbow trout were lower than those from microsomal preparations reported in the literature. Sodium pump activity (ouabain sensitive NaK-ATPase) was demonstrable at 37/sup 0/C. An ouabain insensitive NaK-ATPase was demonstrable at temperatures below 30/sup 0/C and may represent a Na-ATPase activity reported by others. Energy of activation at 25/sup 0/C for total NaK-ATPase ws 10,500 cal.mole/sup -1/. Mg-baseline activity had an energ… more

Date: January 1, 1979

Creator: Poston, T. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Biomedical and Environmental Research Program of the LASL Health Division. Progress report, January--December 1975

Separate abstracts were prepared for the six sections of the report. (HLW)

Date: April 1, 1976

Creator: Petersen, D. F. & Sullivan, E. M. (comps.)

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Photochemistry and photobiology of DNA containing 5-iodouracil and 5-iodocytosine. [Escherichia coli, Bacillus subtilis]

The quantum yields for the photolysis of iodinated derivatives of cytosine (leading to the loss of iodine) has been measured for 313 nm radiation and found to decrease from 0.024 for IodCMP down to 0.007 for both Poly(C) and DNA containing 5-IodCyt. In DNA, approximately 1 clean chain break and 1 alkali-labile bond were formed for every 10 iodines lost. Incorporation of iodinated cytosine or uracil into the DNA of Escherichia coli or Bacillus subtilis was shown to have a large effect on the bio… more

Date: January 1, 1978

Creator: Rahn, R.O.; Stafford, R.S. & Hadden, C.T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Polycyclic aromatic hydrocarbon-protein interactions. Progress report, September 1, 1977--February 28, 1979

In the interactions of bovine serum albumin (BSA) and benzo(a)pyrene (BaP), various BaP derivatives are formed. The BSA-BaP complex exhibits three types of fluorescences: visible fluorescence, modified by the formation of hydroxy-BaP derivatives, and two ultraviolet fluorescences (one probably from pyrene-like products and the other from unidentified products). When irradiated with uv (365 nm), BaP products are photo-bound. The benzene extract, which removes non-covalently bound BaP and its pro… more

Date: October 1, 1978

Creator: Fujimori, E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Comparison of in-vitro and in-vivo studies with coal liquids from the SRC-II process

Coal liquids obtained from the SRC-II process and fractions prepared from these liquids have been assayed in a number of in vivo and in vitro systems for biological activity. The in vitro systems includes: (1) the standard Ames Salmonella typhimurium reverse mutation assay, (2) the S. typhimurium fluctuation test; (3) forward mutation assay in S. typhimurium (8-Ag) test; (4) prophage induction (INDUCTEST); (5) Syrian hamster ovary (SHE) cell transformation assay; and (6) Chinese hamster ovary (… more

Date: September 1, 1983

Creator: Mahlum, D. D.; Frazier, M. E.; Pelroy, R. A. & Renne, R. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department