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Biomedical subjects

C J Gillespie

Publications and source records attributed to C J Gillespie.

17 recordsLinked to original sources
PubMed1979

Radioprotection by DMSO of mammalian cells exposed to X-rays and to heavy charged-particle beams.

Populations of G1-phase Chinese hamster cells in stirred suspensions containing various concentrations of DMSO were irradiated with 250 kV X-rays or various heavy charged-particle beams. Chemical radioprotection of cell inactivation was observed for all LET values studied. When cell survival data were resolved into linear and quadratic components, the extent and concentration dependence of DMSO protection were found to be different for the two mechanisms. The chemical kinetics of radioprotection for single-events were similar for LET values up to those which gave the maximum RBE. DMSO protected to a lesser extent against energetic argon ions at an median LET of approximately 220 keV/micron. These data could indicate the contribution of indirect action by hydroxyl radicals and hydrogen atoms to cell inactivation by single-hit and double-hit mechanisms for various radiation qualities. The decrease in RBE observed at very high LET may result, in part, from reduced yields of water radicals at 10(-9)-10(-8) s resulting from radical recombination mechanisms within the charged particle tracks.

Animals↗
PubMed1976

DNA strand breaks, repair, and survival in x-irradiated mammalian cells.

The yields of unrepairable single-and double-strand breaks in the DNA of x-irradiated Chinese hamster cells were measured by low-speed neutral and alkaline sucrose density gradient sedimentation in order to investigate the relation between these lesions and reproductive death. After maximal single-strand remoining, at all doses, the number of residual single-strand breaks was twice the number of residual double-strand breaks. Both double-strand and unrepairable single-strand breaks were proportional to the square of absorbed dose, in the range 10-50 krad. No rejoining of double-strand breaks was observed. These observations suggest that, in mammalian cells, most double-strand breaks are not repairable, while all single-strand breaks are repaired except those that are sufficiently close on complementary strands to constitute double-strand breaks. Comparison with cell survival measurements at much lower doses suggests that loss of reproductive capacity corresponds to induction of approximately one double-strand break.

Cell Line↗
PubMed1975

Kinetics of the single-strand repair mechanism in mammalian cells.

Alkaline sucrose gradient measurements of single-strand breaks from sublethal X-ray doses yield the same breakage efficiency as from lethal doses. Repair of the breaks is random, first order with a single rate constant, and characterized by 24 kcal/mole activation energy.

Cell Line↗
PubMed1971

MEDLARS abbreviations for medical journal titles.

The National Library of Medicine announces its adoption of the Anglo-American standard for the formulation of journal title abbreviations according to the American National Standard for the Abbreviation of Titles of Periodicals (1969), with individual words abbreviated, in turn, according to the International List of Periodical Title Word Abbreviations (1970). The history of the activity of the specific Z39 Committee of USASI (now ANSI) concerned with journal title abbreviations is reviewed, covering the period from 1962 to the present. A history of the National Clearinghouse for Periodical Title Word Abbreviations and of the International List is also given. Former NLM usage is compared with the forms of the present International List and examples show the major changes in NLM abbreviations. The NLM Rules for Abbreviation of Periodical Titles as derived from the new standard are appended.

Abbreviations as Topic↗