Fate of Ascorbic Acid in Early Radiation Damage.

AbstractClinical radiodiagnosis and radiotherapy sometimes induce tissue damage and/or increase the risk of cancer in patients. However, in radiodiagnosis, a reduction in the exposure dose causes a blockier image that is not acceptable for diagnosis. Approximately 70% of DNA damage is induced via reactive oxygen species and/or radicals created during X-ray irradiation. Therefore, treatment with anti-oxidants and/or radical scavengers is considered to be effective in achieving a good balance between image quality and damage. However, few studies have examined the effect of using radical scavengers to reduce radiation damage in the clinical setting. In this study, we administrated 20 mg/kg ascorbic acid (AA) to patients before cardiac catheterization (CC) for diagnostic purposes. We analyzed changes in the number of phosphorylated H2AX (γH2AX) foci (a marker of DNA double-strand breaks) in lymphocytes, red blood cell glutathione levels, blood cell counts, and biochemical parameters. Unfortunately, we did not find satisfactory evidence to show that AA treatment reduces γH2AX foci formation immediately after CC. AA treatment did, however, cause a higher reduced/oxidized glutathione ratio than in the control arm immediately after CC. This is a preliminary study, but this result suggests that reducing radiation damage in clinical practice can be achieved using a biological approach.

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Early Effects of Ionizing Radiation on the Collagen Hierarchical Structure of Bladder and Rectum Visualized by Atomic Force Microscopy

Microscopy and Microanalysis ◽

10.1017/s1431927618000065 ◽

2018 ◽

Vol 24 (1) ◽

pp. 38-48 ◽

Cited By ~ 2

Author(s):

Svetlana L. Kotova ◽

Peter S. Timashev ◽

Galina V. Belkova ◽

Marina V. Kochueva ◽

Ksenia V. Babak ◽

...

Keyword(s):

Atomic Force Microscopy ◽

Ionizing Radiation ◽

Radiation Damage ◽

Three Dimensional ◽

Collagen Matrix ◽

Destructive Effect ◽

Force Microscopy ◽

Additional Information ◽

Atomic Force ◽

Early Radiation

AbstractRadiation therapy, widely used in the treatment of a variety of malignancies in the pelvic area, is associated with inevitable damage to the surrounding healthy tissues. We have applied atomic force microscopy (AFM) to track the early damaging effects of ionizing radiation on the collagen structures in the experimental animals’ bladder and rectum. The first signs of the low-dose radiation (2 Gy) effect were detected by AFM as early as 1 week postirradiation. The observed changes were consistent with initial radiation destruction of the protein matrix. The alterations in the collagen fibers’ packing 1 month postirradiation were indicative of the onset of fibrotic processes. The destructive effect of higher radiation doses was probed 1 day posttreatment. The severity of the radiation damage was proportional to the dose, from relatively minor changes in the collagen packing at 8 Gy to the growing collagen matrix destruction at higher doses and complete three-dimensional collagen network restructuring towards fibrotic-type architecture at the dose of 22 Gy. The AFM study appeared superior to the optical microscopy-based studies in its sensitivity to early radiation damage of tissues, providing valuable additional information on the onset and development of the collagen matrix destruction and remodeling.

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THE USE OF CHROMIUM-51 AS A SENSITIVE QUANTITATIVE CRITERION OF EARLY RADIATION DAMAGE TO RAT THYMOCYTES

Canadian Journal of Biochemistry ◽

10.1139/o64-059 ◽

1964 ◽

Vol 42 (4) ◽

pp. 503-512 ◽

Cited By ~ 24

Author(s):

J. F. Scaife ◽

P. V. Vittorio

Keyword(s):

Cell Death ◽

Radiation Damage ◽

Morphological Changes ◽

Quantitative Criterion ◽

Early Radiation

The uptake of Cr61-chromate by thymocytes in suspension can be used as a sensitive quantitative criterion for the evaluation of early radiation damage to these cells, often under situations where other methods of assessing cell death such as morphological changes do not yield valid results. The development of a radiation lesion is characterized by a reduction in the uptake of Cr51, which in vitro can be detected 1 hour following irradiation and with doses as low as 25 rads. By means of this technique thymocytes have been shown to be completely protected by anoxia to doses of up to 150 rads, but at higher levels anoxia affords little protection. No protection of thymocytes could be demonstrated in vivo with S,β-aminoethylisothiouronium bromide hydrobromide (AET) or serotonin at 0.72 mmoles per kg. L-Cysteine, cysteamine, and serotonin at 1 mM concentration in vitro showed no protection of thymocytes provided they were removed from the cells immediately subsequent to irradiation.

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CONCERNING THE INFLUENCE OF HEAD IRRADIATION ON THE DEVELOPMENT OF RADIATION DAMAGE IN THE RAT THYMUS

Canadian Journal of Biochemistry ◽

10.1139/o64-075 ◽

1964 ◽

Vol 42 (5) ◽

pp. 623-629 ◽

Cited By ~ 2

Author(s):

J. F. Scaife

Keyword(s):

Radiation Damage ◽

Dna Content ◽

Whole Body ◽

Low Doses ◽

Nucleotide Content ◽

Wet Weight ◽

Early Radiation

Early radiation damage in rat thymocytes has been assessed at 4 hours and 24 hours following varying doses of whole body irradiation and compared with the effects produced by a dose of 1000 rads to the head only of the animal. The indirect dose to the shielded thymus in these head irradiation experiments was found to be 22 rads. The criteria employed to assess the radiation damage were: changes in wet weight, DNA content, pyknosis, Cr51 uptake, supernatant NADase alkaline RNAase and soluble RNA and nucleotide content of the thymus. No radiation damage beyond what could be expected from scattered irradiation was produced in the thymus by head irradiation only. Adrenalectomized and hypophysectomized animals showed no difference in their response to whole body irradiation as compared to unoperated controls. It is concluded that the adenohypophysis response of irradiation is not involved in the death or damage of thymocytes following low doses of whole body irradiation.

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