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At least 19 recordsLinked to original sources
PubMed1977

Tensile strength of fascia lata sutures following gamma radiation.

Gamma radiation (Co-60) is used to sterilize biological sutures. We wished to compare the effect of gamma-radiation in doses of 2.7 and 4.0 Mrads on the tensile strength of human fascia lata sutures obtained from the same cadaver. Five variables of tensile strength viz. Breaking Elongation, Breaking Load, Yield Point Load, Work of Rupture and Elastic Stiffness were determined for each suture. For Breaking Elongation the mean strength for the 4.0 Mrad dose was 3% less than for 2.7 Mrad dose (P less than 0.05); for Breaking Load 11% less (P less than 0.01); for Yield Point Load 9% less (P less than 0.02); for Work of Rupture 14% less (P less than 0.01); and for Elastic Stiffness 8% less (P less than 0.02). Irradiation with 4.0 Mrads, does not greatly change the tensile strength characteristics of fascia lata sutures.

Adult↗
PubMed1975

recA+-dependent inactivation of the lambda repressor in Escherichia coli lysogens by gamma-radiation and by tif expression.

When gamma lysogens of E. coli are induced by gamma-radiation the gamma repressor, as measured by its specific binding to gamma DNA, is rapidly inactivated by a recA+-dependent process which does not require new protein synthesis. This rapid inactivation is similar to inactivation of repressor by expression of the temperature sensitive E. coli mutation tif. In contrast, induction by UV irradiation or mitomycin C treatment requires new protein synthesis and there is a lag before the repressor is inactivated (Tomizawa and Ogawa, 1967; Shinagawa and Itoh, 1973).

Coliphages↗
PubMed1992

Involvement of RecB-mediated (but not RecF-mediated) repair of DNA double-strand breaks in the gamma-radiation production of long deletions in Escherichia coli.

Experiments were designed to determine the association between the repair of gamma-radiation-induced DNA double-strand breaks (DSB) and the induction of 700-1000 bp long deletions (Lac(-)----Lac+), base substitutions (leuB19----Leu+), and frameshifts (trpE9777----Trp+) in Escherichia coli K-12. Over the range of 2.5-20 krad, deletions were induced with linear kinetics, as has been shown for the induction of DSB, while the induction kinetics of base substitutions and frameshifts were curvilinear. Like the repair of DSB, deletion induction showed an absolute requirement for an intact recB gene as well as a dependency on the type of preirradiation growth medium; these requirements were not seen for base substitutions or frameshifts. In addition, about 80% of the spontaneous deletions were absent in the recB21 strain. A recC1001 mutation, which confers a 'hyper-Rec' phenotype, increased the rate of gamma-radiation-induced deletions as well as the low-dose production of base substitutions and frameshifts. A recF143 mutation increased the yield of gamma-radiation-induced deletions without increasing base substitutions or frameshifts. A mutS mutation markedly enhanced the gamma-radiation induction of frameshifts, and had a slight effect on base substitutions, but did not affect the induction of deletions. Resistance to gamma-irradiation and the capacity to repair DSB (albeit at about half the normal rate) were restored to the radiosensitive recB21 strain by the addition of the sbcB21 and sbcC201 mutations. However, the radioresistant recB sbcBC strain, which is recombination proficient via the RecF pathway, was still grossly deficient in the ability to produce deletions. A model for deletion induction as a by-product of the recB-dependent (Chi-dependent) repair of gamma-radiation-induced DSB is discussed, as is the inability to detect deletions in cells that use only the recF-dependent (Chi-independent) mechanism to repair DSB.

Bacterial Proteins↗
PubMed1976

The effect of gamma radiation on the cysticerci of Taenia solium.

Cysticerci of Taenia solium were exposed to gamma radiation in doses varying from 20-140 krad. Radiation had an adverse effect on the ability of the cysticerci to evaginate in vitro after a time lag of 9 days. This effect was most marked at doses of 100 krad and higher, thus no cysticerci exposed to 140, 120 and 100 krad evaginated after 12, 18 and 21 days, respectively. On Day +24, when 60% of the control cysticerci evaginated, 55%, 50%, 30% and 40% of the cysticerci exposed to 20, 40, 60, and 80 krad, respectively, evaginated in vitro. Cysticerci exposed to radiation doses of 20-120 krad are as infective to golden hamsters as are unirradiated cysticerci. Cestodes resulting from irradiated cysticerci, however, cannot maintain themselves indefinitely, and are excreted or digested at varying times from Day +12 onwards. Moreover, cestodes resulting from such irradiated cysticerci do not grow, but are resorbed, and finally consist of only a scolex. By Day +30 the mean length of the worms resulting from the unirradiated cysticerci is 173,8 mm, while those resulting from cysticerci exposed to 20 and 40 krad consist of scolices only and the hamsters fed material exposed to 60 krad were negative. It appears, therefore, that radiation inhibits the ability of the cells in the neck region to divide and thus form new proglottids. Carcasses infested with cysticercosis can possibly be rendered fit for human consumption by exposure to gamma radiation at doses between 20 and 60 krad.

Animals↗
PubMed1979

Effect of ultraviolet and gamma-radiation on Herpetomonas samuelpessoai.

A study was made about the influence of ultraviolet (UV) and gamma-radiations on Herpetomonas samuelpessoai grown either in a chemically defined or in a complex medium. Cells cultivated in defined medium were more sensitive to UV than those from complex medium, as estimated by inhibition of cellular growth. The effect of gamma-radiation, however, was independent of the media in which the cells were grown. Both radiations interfere with the plasma membrane as analysed by parameters such as excretion of cellular material and concanavalin-A-induced agglutination. Doses of UV which inhibit the cellular growth do not interfere with the plasma membrane. With gamma-radiation, however, doses which inhibit cellular growth also interfere with the plasma membrane. These results suggest that for certain applications UV radiation may be an advantage in vaccine production.

Agglutination↗