Dose Responses for Chromosome Aberrations Produced in Noncycling Primary Human Fibroblasts by Alpha Particles, and by Gamma Rays Delivered at Sublimiting Low Dose Rates

2002 ◽  
Vol 158 (1) ◽  
pp. 43-53 ◽  
Author(s):  
Michael N. Cornforth ◽  
Susan M. Bailey ◽  
Edwin H. Goodwin
Keyword(s):  
Gamma Rays ◽  
Chromosome Aberrations ◽  
Low Dose ◽  
Human Fibroblasts ◽  
Alpha Particles ◽  
Dose Rates ◽  
Dose Responses

Ovarian Dysfunction in Fetally Irradiated Beagles

1977 ◽  
Vol 35 ◽  
pp. 658-659
Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Low Dose ◽  
Long Term Effects ◽  
Ovarian Dysfunction ◽  
Dose Rates ◽  
Highly Sensitive ◽  
Microscopic Evaluation ◽  
Ovarian Pathology ◽  
Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

No Lengthening of Life Span in Mice Continuously Exposed to Gamma Rays at Very Low Dose Rates

2003 ◽  
Vol 160 (3) ◽  
pp. 376-379 ◽  
Author(s):  
S. Tanaka ◽  
I. B. Tanaka ◽  
S. Sasagawa ◽  
K. Ichinohe ◽  
T. Takabatake ◽  
...  
Keyword(s):  
Life Span ◽  
Gamma Rays ◽  
Low Dose ◽  
Dose Rates

scholarly journals Delayed Numerical Chromosome Aberrations in Human Fibroblasts by Low Dose of Radiation

2015 ◽  
Vol 12 (12) ◽  
pp. 15162-15172 ◽  
Author(s):  
Yoon Cho ◽  
Su Kim ◽  
Hae Woo ◽  
Yang Kim ◽  
Sung Ha ◽  
...  
Keyword(s):  
Chromosome Aberrations ◽  
Low Dose ◽  
Human Fibroblasts ◽  
Numerical Chromosome

Dose-Rate Effects of Protons and Light Ions for DNA Damage Induction, Survival and Transformation in Apparently Normal Primary Human Fibroblasts

2021 ◽  
Author(s):  
Paula V. Bennett ◽  
Alicia M. Johnson ◽  
Sarah E. Ackerman ◽  
Pankaj Chaudhary ◽  
Deborah J. Keszenman ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Survival ◽  
Dose Rate ◽  
Low Dose ◽  
Human Fibroblasts ◽  
Dose Rates ◽  
In Vitro Transformation ◽  
Dose Rate Effects ◽  
Rate Effects

We report on effects of low-dose exposures of accelerated protons delivered at high-dose rate (HDR) or a simulated solar-particle event (SPE) like low-dose rate (LDR) on immediate DNA damage induction and processing, survival and in vitro transformation of low passage NFF28 apparently normal primary human fibroblasts. Cultures were exposed to 50, 100 and 1,000 MeV monoenergetic protons in the Bragg entrance/plateau region and cesium-137 γ rays at 20 Gy/h (HDR) or 1 Gy/h (LDR). DNA double-strand breaks (DSB) and clustered DNA damages (containing oxypurines and abasic sites) were measured using transverse alternating gel electrophoresis (TAFE) and immunocytochemical detection/scoring of colocalized γ-H2AX pS139/53BP1 foci, with their induction being linear energy transfer (LET) dependent and dose-rate sparing observed for the different damage classes. Relative biological effectiveness (RBE) values for cell survival after proton irradiation at both dose-rates ranged from 0.61–0.73. Transformation RBE values were dose-rate dependent, ranging from ∼1.8–3.1 and ∼0.6–1.0 at low doses (≤30 cGy) for HDR and LDR irradiations, respectively. However peak transformation frequencies were significantly higher (1.3–7.3-fold) for higher doses of 0.5–1 Gy delivered at SPE-like LDR. Cell survival and transformation frequencies measured after low-dose 500 MeV/n He-4, 290 MeV/n C-12 and 600 MeV/n Si-28 ion irradiations also showed an inverse dose-rate effect for transformation at SPE-like LDR. This work demonstrates the existence of inverse dose-rate effects for proton and light-ion-induced postirradiation cell survival and in vitro transformation for space mission-relevant doses and dose rates.

Influence of Various Commercial Packaging Conditions on Survival of Escherichia coli O157:H7 to Irradiation by Electron Beam Versus Gamma Rays

1999 ◽  
Vol 62 (1) ◽  
pp. 10-15 ◽  
Author(s):  
VERÓNICA LÓPEZ-GONZÁLEZ ◽  
PETER S. MURANO ◽  
ROBERT E. BRENNAN ◽  
ELSA A. MURANO
Keyword(s):  
Escherichia Coli ◽  
Electron Beam ◽  
Gamma Rays ◽  
Low Dose ◽  
Microbial Population ◽  
Escherichia Coli O157 ◽  
Dose Rates ◽  
Polyethylene Bags ◽  
Effect Of Oxygen ◽  
Permeability Rate

Irradiation of ground beef patties inoculated with the organism Escherichia coli O157:H7 was performed either by gamma rays from a cobalt 60 source or by electron beam generated by a linear accelerator. Patties were packaged in one of the following materials: nylon/polyethylene bags, Saran/polyester/polyethylene bags (PM2), or Saran overwrap with a Styrofoam tray inside. Bags were sealed in air or under vacuum and were irradiated at either 5 or −15°C. Average D10 values (dose required to inactivate 90% of a microbial population) ranged from 0.27 to 0.63 kGy, depending on the conditions. Overall, higher D10 values (P < 0.0001) were obtained upon irradiation at −15°C as compared with 5°C. Cells inoculated in samples packaged in PM2 had the highest D10 values, but only if irradiated by electron beam at −15°C (P < 0.001). Since PM2 had the lowest oxygen permeability rate and since the temperature was too low for radicals to migrate easily, these conditions may have minimized the effect of oxygen- and water-derived radicals on microbial survival. Irradiation by gamma rays resulted in higher D10 values (P < 0.047) than irradiation by electron beam, with the highest values being observed at −15°C. Differences may be attributed to dose rate (1.0 kGy/h for gamma, 17 kGy/min for electron beam) since it is possible that, at low dose rates, microbial enzymes may have more time to repair damage to the cell due to irradiation, resulting in higher D10 values.

Cause of Death and Neoplasia in Mice Continuously Exposed to Very Low Dose Rates of Gamma Rays

2007 ◽  
Vol 167 (4) ◽  
pp. 417-437 ◽  
Author(s):  
I. B. Tanaka ◽  
S. Tanaka ◽  
K. Ichinohe ◽  
S. Matsushita ◽  
T. Matsumoto ◽  
...  
Keyword(s):  
Cause Of Death ◽  
Gamma Rays ◽  
Low Dose ◽  
Dose Rates
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