An Analysis of the LD 50(30) as Related to Radiation Intensity

Logie, Loren C.; Harris, Monica; Tatsch, Robert E; Hooser, E. N. van

doi:10.2307/3571043

Cited by 20 publications

(4 citation statements)

References 4 publications

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“…Calibration of the source for these experiments was performed by measuring midline absorbed doses in agarose gel phantoms of a rat with embedded plastic vials containing Fricke solution, and doses were determined by spectrophotometry. Based on literature data, the dose of 6.7 Gy was selected as a potential LD 50 dose at 30 days post-irradiation (LD 50/30 ) (8,11,15,16). Unanesthetized animals were confined in custom made individual cages made of wire.…”

Section: Methodsmentioning

confidence: 99%

Increased survival after irradiation followed by regeneration of bone marrow stromal cells with a novel thiol-based radioprotector

et al. 2014

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AimTo investigate the survival of laboratory rats after irradiation and to study the cellularity of their bone marrow and the multipotential mesenchymal stem cells (BM-MSCs) in groups treated with or without a new thiol-based radioprotector (GM2011)MethodsAnimals were irradiated by a Cobalt gamma source at 6.7 Gy. Treated animals were given i.p. GM2011 30 minutes before and 3 and 7 hours after irradiation. Controls consisted of sham irradiated animals without treatment and animals treated without irradiation. After 30 days post-irradiation, animals were sacrificed and bone marrow cells were prepared from isolated femurs. A colony forming unit-fibroblast (CFU-F) assay was performed to obtain the number of BM-MSCs.ResultsIn the treated group, 87% of animals survived, compared to only 30% in the non-treated irradiated group. Irradiation induced significant changes in the bone marrow of the treated rats (total bone marrow cellularity was reduced by ~ 60% – from 63 to 28 cells ×106/femur and the frequency of the CFU-F per femur by ~ 70% – from 357 to 97), however GL2011 almost completely prevented the suppressive effect observed on day 30 post-irradiation (71 cells ×106/femur and 230 CFU-F/femur).ConclusionAlthough the irradiation dosage was relatively high, GL2011 acted as a very effective new radioprotector. The recovery of the BN-MSCs and their counts support the effectiveness of the studied radioprotector.

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Section: Methodsmentioning

confidence: 99%

Increased survival after irradiation followed by regeneration of bone marrow stromal cells with a novel thiol-based radioprotector

et al. 2014

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“…Non-anesthetized immobilized animals were positioned in individual cages made of wire and arranged in a circle around the source (6 rats per session). The distance from the source was 25 cm, as per [22], where a similar setup and source were used. Body irradiation was performed with rats placed sideways to the source.…”

Section: Experimental Designmentioning

confidence: 99%

“…Body irradiation was performed with rats placed sideways to the source. The animals received 6.7 Gy radiation at a dose rate (0.41 Gy/min), which, based on literature data, corresponds to a LD50/30 dose [22][23][24]. In the middle of a course of radiation treatment, the cages with rats were sideways rotated by 180° to provide uniform, whole-body irradiation.…”

Section: Experimental Designmentioning

confidence: 99%

Raman spectral analysis of the brainstem and responses of neuroglia and cytokines in whole-body gamma-irradiated rats after administration of aminothiol-based radioprotector GL2011

Kocovic

Bajuk‐Bogdanović

Maslovarić

et al. 2021

ARCH BIOL SCI BELGRA

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The search for an effective and non-toxic radioprotector is ongoing. We tested a novel, natural aminothiol-based radioprotector, GL2011, that was applied 30 min, 3 h or 6 h after the exposure of male albino Wistar rats to a 6.7 Gy sublethal dose of gamma radiation. The molecular signatures of radioprotection were investigated with Raman microspectroscopy of brainstem tissue samples. Morphological changes and activation of astrocytes and microglia were assessed by immunohistochemistry. Global markers of neuroinflammation were followed by ELISA to monitor blood plasma levels of proinflammatory (IL-6 and TNF-?) and antiinflammatory (IL-10) cytokines. A thirty-day follow-up determined that survival of unprotected animals was 44%. A survival increase was observed after radioprotection (75%, irrespective of the time of application). Raman spectra revealed a slightly deleterious effect of radiation on nucleic acids in surviving animals that was mitigated with the radioprotector, as GL2011 preserved the morphology of both astrocytes and microglia, with reduced microglial infiltration. Cytokine assessment revealed an immunomodulatory effect of the novel radioprotector. The overall results point out the positive effects of a single dose of GL2011 applied at different times. The molecular and cellular changes in the brainstem indicate that the radioprotector applied after radiation conferred better protection, which underlines its translation to cure radiation accidents.

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“…The results from these analyses showed that the MED decreases when dose rate increases and eventually approaching a minimum constant level, but it increases sharply at very low dose rates. The relationships of LD 50 (the lethal dose 50, the lethal dose for 50% of the group) to the dose rate of low-LET (Linear Energy Transfer) radiation exposure for marrow-syndrome lethality in human (Ainsworth et al, 1965), rat (Logie et al, 1960), mouse (Koznova, 1978), and other species have been reported. These studies showed that the curves for LD 50 versus dose rate converge at high dose rates to a common LD 50 for dog, swine, goat, and human (Scott et al, 1988).…”

Section: Discussionmentioning

confidence: 99%

A quantitative model for the evaluation of dose rates effects following exposure to low-dose gamma-radiation

Ogata

Furukawa²,

Kawakami³

et al. 2005

Radioprotection

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Simultaneous consideration of the irradiation time and the cumulative dose isnecessary for evaluating the risk of long-term exposure to radiation at low dose. This study intends to examine several numerical relationships between doses and dose rates in biological responses to gamma radiation. Data on inhibition of [ 3 H] thymidine uptake and micronucleus formation in human osteosarcoma cells were analyzed using the median effective dose (MED) as a measure of the risk. MEDs were calculated using parameters estimated by fitting general logistic curves to the dose-response relationships for each group defined by irradiation time. Both biological responses, the inhibition of [ 3 H] thymidine uptake and micronucleus formation, decreased sharply when the dose rates were less than 0.01 Gy/h. Exponential functions were fitted to the log relationships between MEDs and dose rates. This modified exponential model described well the quantitative effect of dose rates on MEDs, and suggested that risk is extremely low at very low dose rates.

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An Analysis of the LD 50(30) as Related to Radiation Intensity

Cited by 20 publications

References 4 publications

Increased survival after irradiation followed by regeneration of bone marrow stromal cells with a novel thiol-based radioprotector

Increased survival after irradiation followed by regeneration of bone marrow stromal cells with a novel thiol-based radioprotector

Raman spectral analysis of the brainstem and responses of neuroglia and cytokines in whole-body gamma-irradiated rats after administration of aminothiol-based radioprotector GL2011

A quantitative model for the evaluation of dose rates effects following exposure to low-dose gamma-radiation

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