Meta-analysis of non-tumour doses for radiation-induced cancer on the basis of dose-rate

Purpose: Quantitative analysis of cancer risk of ionising radiation as a function of dose-rate

Radiation cancer risk at different dose rates: new dose-rate effectiveness factors derived from revised A-bomb radiation dosimetry data and non-tumor doses

Abstract The dose rate of atomic bomb (A-bomb) radiation to the survivors has still remained unclear, although the dose–response data of A-bomb cancers has been taken as a standard in estimating the cancer risk of radiation and the dose and dose-rate effectiveness factor (DDREF). Since the applicability of the currently used DDREF of 2 derived from A-bomb data is limited in a narrow dose-rate range, 0.25-75 Gy/min as estimated from analysis of DS86 dosimetry data in the present study, a non-tumor dose (Dnt) was applied in an attempt to gain a more universal dose-rate effectiveness factor (DREF), where Dnt is an empirical parameter defined as the highest dose at which no statistically significant tumor increase is observed above the control level and its magnitude depends on the dose rate. The new DREF values were expressed as a function of the dose rate at four exposure categories, i.e. partial body low LET, whole body low linear energy transfer (LET), partial body high LET and whole body high LET and provided a value of 14 for environmental level radiation at a dose rate of 10−9 Gy/min for whole body low LET.</jats:p

Radiation-induced versus endogenous DNA damage: commentary on Pollycove and Feinendegen

Quantitative comparison of ROS-induced endogenous DNA damage with DNA damage induced by ionizing radiation at environmental level, presented by Pollycove and Feinedegen, is timely and provides basic date for establishing a a sound rule for radiation protection. Main point added to their estimation is quantitative data on oxidative damage to DNA precursormolecules, such as oxo dGTP and their cellular decomposition efficiency. If the precursor damages are taken into accout, the amount of initial endogenous DNA damage would be increased by a factor of 100-10000

Transformation of Germinated Spores of <i>Bacillus subtilis</i> on Agar Plates

l -Alanine-germinated spores of Bacillus subtilis developed a competence on agar plates after 10 h of incubation. Addition of marker amino acid to the plates was required for the transformation. </jats:p