Primary DNA Damage Assessed With the Comet Assay and Comparison to the Absorbed Dose of Diagnostic X-rays in Children

2009 ◽  
Vol 28 (5) ◽  
pp. 405-416 ◽  
Author(s):  
Đurđica Milković ◽  
Vera Garaj-Vrhovac ◽  
Mária Ranogajec-Komor ◽  
Saveta Miljanić ◽  
Goran Gajski ◽  
...  
Keyword(s):  
Dna Damage ◽  
Comet Assay ◽  
Absorbed Dose ◽  
Peripheral Blood Lymphocytes ◽  
X Rays ◽  
X Ray ◽  
Before And After ◽  
The Individual ◽  
Dose Measurements ◽  
Posterior Anterior

The aim of this work is to assess DNA damage in peripheral blood lymphocytes of children prior to and following airway X-ray examinations of the chest using the alkaline comet assay and to compare data with the measured absorbed dose. Twenty children with pulmonary diseases, between the ages of 5 and 14 years, are assessed. Absorbed dose measurements are conducted for posterior–anterior projection on the forehead, thyroid gland, gonads, chest, and back. Doses are measured using thermoluminescent and radiophotoluminescent dosimetry systems. Differences between tail lengths, tail intensity, and tail moments as well as for the long-tailed nuclei before and after exposures are statistically significant and are dependent on the individual. The results demonstrate the usefulness of the comet assay as a measure of X-ray damage to lymphocytes in a clinical setting. Doses measured with both dosimeters show satisfactory agreement (0.01 mSv) and are suitable for dosimetric measurements in X-ray diagnostics.

scholarly journals DNA Damage and Repair Capacity in Patients With Lung Cancer: Prediction of Multiple Primary Tumors

2008 ◽  
Vol 26 (21) ◽  
pp. 3560-3566 ◽  
Author(s):  
Irene Orlow ◽  
Bernard J. Park ◽  
Urvi Mujumdar ◽  
Himali Patel ◽  
Puiki Siu-Lau ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Dna Damage ◽  
Comet Assay ◽  
Peripheral Blood Lymphocytes ◽  
Repair Capacity ◽  
Dna Damage And Repair ◽  
Primary Tumors ◽  
Multiple Primary Tumors ◽  
Multiple Primary ◽  
Before And After

PurposePatients who survive one occurrence of non–small-cell lung cancer (NSCLC) are at higher risk of a second malignancy. Capacity to repair damaged DNA may modulate individual susceptibility to develop lung cancer. Therefore, we evaluated constitutive and induced DNA damage, and repair capacity, in patients with multiple NSCLCs (cases) and compared the results to those obtained in patients with a single NSCLC (controls).Patients and MethodsOne hundred eight cases and 99 controls matched by age, sex, and time since diagnosis were studied. DNA damage was assessed on peripheral blood lymphocytes by the comet assay before and after exposing cells to a tobacco-derived carcinogen, using the tail moment and the tail intensity as measures to assess baseline damage, induced damage and repair capacity.ResultsConstitutive DNA damage, benzo(a)pyrene diol epoxide–induced damage, and repair after BPDE-induced damage were all significantly higher in cases than in controls. These results were confirmed in regression analyses adjusted for potential confounders.ConclusionDNA damage as measured by the comet assay is associated with the development of multiple primary tumors in individuals with NSCLC.

scholarly journals Exposure of the cytoplasm to low-dose X-rays modifies ataxia telangiectasia mutated-mediated DNA damage responses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Munetoshi Maeda ◽  
Masanori Tomita ◽  
Mika Maeda ◽  
Hideki Matsumoto ◽  
Noriko Usami ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Ataxia Telangiectasia ◽  
Kinase Inhibitor ◽  
Surrogate Marker ◽  
X Rays ◽  
Ataxia Telangiectasia Mutated ◽  
Whole Cell ◽  
X Ray ◽  
Dna Damage Responses

AbstractWe recently showed that when a low X-ray dose is used, cell death is enhanced in nucleus-irradiated compared with whole-cell-irradiated cells; however, the role of the cytoplasm remains unclear. Here, we show changes in the DNA damage responses with or without X-ray microbeam irradiation of the cytoplasm. Phosphorylated histone H2AX foci, a surrogate marker for DNA double-strand breaks, in V79 and WI-38 cells are not observed in nucleus irradiations at ≤ 2 Gy, whereas they are observed in whole-cell irradiations. Addition of an ataxia telangiectasia mutated (ATM) kinase inhibitor to whole-cell irradiations suppresses foci formation at ≤ 2 Gy. ABL1 and p73 expression is upregulated following nucleus irradiation, suggesting the induction of p73-dependent cell death. Furthermore, CDKN1A (p21) is upregulated following whole-cell irradiation, indicating the induction of cell cycle arrest. These data reveal that cytoplasmic radioresponses modify ATM-mediated DNA damage responses and determine the fate of cells irradiated at low doses.

scholarly journals Physical and chemical imaging of adhesive interfaces with soft X-rays

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Hiroyuki Yamane ◽  
Masaki Oura ◽  
Osamu Takahashi ◽  
Tomoko Ishihara ◽  
Noriko Yamazaki ◽  
...  
Keyword(s):  
Molecular Level ◽  
Covalent Bond ◽  
Chemical Imaging ◽  
Diglycidyl Ether ◽  
X Rays ◽  
X Ray ◽  
Covalent Bond Formation ◽  
Chemical States ◽  
The Individual ◽  
Physical And Chemical

AbstractAdhesion is an interfacial phenomenon that is critical for assembling carbon structural composites for next-generation aircraft and automobiles. However, there is limited understanding of adhesion on the molecular level because of the difficulty in revealing the individual bonding factors. Here, using soft X-ray spectromicroscopy we show the physical and chemical states of an adhesive interface composed of a thermosetting polymer of 4,4’-diaminodiphenylsulfone-cured bisphenol A diglycidyl ether adhered to a thermoplastic polymer of plasma-treated polyetheretherketone. We observe multiscale phenomena in the adhesion mechanisms, including sub-mm complex interface structure, sub-μm distribution of the functional groups, and molecular-level covalent-bond formation. These results provide a benchmark for further research to examine how physical and chemical states correlate with adhesion, and demonstrate that soft X-ray imaging is a promising approach for visualizing the physical and chemical states at adhesive interfaces from the sub-mm level to the molecular level.

scholarly journals The use of fricke dosimetry for low energy x-rays

2006 ◽  
Vol 49 (spe) ◽  
pp. 17-23 ◽  
Author(s):  
Carlos de Austerlitz ◽  
Viviane Souza ◽  
Heldio Pereira Villar ◽  
Aloisio Cordilha
Keyword(s):  
Ionization Chamber ◽  
Parallel Plate ◽  
Low Energy ◽  
Calibration Factor ◽  
X Rays ◽  
Measuring Systems ◽  
X Ray ◽  
Dose Measurements

The performance of four X-ray qualities generated in a Pantak X-ray machine operating at 30-100 kV was determined with a parallel-plate ionization chamber and a Fricke dosimeter. X-ray qualities used were those recommended by Deutsch Internationale Normung DIN 6809 and dose measurements were carried out with Plexiglas® simulators. Results have shown that the Fricke dosimeter can be used not only for soft X-ray dosimetry, but also for the maintenance of low-energy measuring systems' calibration factor.

Structural study of the X-ray-induced enzymatic reaction of octahaem cytochromecnitrite reductase

2015 ◽  
Vol 71 (5) ◽  
pp. 1087-1094 ◽  
Author(s):  
A. A. Trofimov ◽  
K. M. Polyakov ◽  
V. A. Lazarenko ◽  
A. N. Popov ◽  
T. V. Tikhonova ◽  
...  
Keyword(s):  
Nitrite Reductase ◽  
Catalytic Reaction ◽  
Active Sites ◽  
Enzymatic Reaction ◽  
Absorbed Dose ◽  
Free Form ◽  
Data Sets ◽  
X Rays ◽  
X Ray ◽  
Site Water

Octahaem cytochromecnitrite reductase from the bacteriumThioalkalivibrio nitratireducenscatalyzes the reduction of nitrite to ammonium and of sulfite to sulfide. The reducing properties of X-ray radiation and the high quality of the enzyme crystals allow study of the catalytic reaction of cytochromecnitrite reductase directly in a crystal of the enzyme, with the reaction being induced by X-rays. Series of diffraction data sets with increasing absorbed dose were collected from crystals of the free form of the enzyme and its complexes with nitrite and sulfite. The corresponding structures revealed gradual changes associated with the reduction of the catalytic haems by X-rays. In the case of the nitrite complex the conversion of the nitrite ions bound in the active sites to NO species was observed, which is the beginning of the catalytic reaction. For the free form, an increase in the distance between the oxygen ligand bound to the catalytic haem and the iron ion of the haem took place. In the case of the sulfite complex no enzymatic reaction was detected, but there were changes in the arrangement of the active-site water molecules that were presumably associated with a change in the protonation state of the sulfite ions.

scholarly journals Corrigendum to: Standardisation of the in vitro comet assay: influence of lysis time and lysis solution composition on the detection of DNA damage induced by X-rays

Mutagenesis ◽  
2019 ◽  
Vol 34 (5-6) ◽  
pp. 431-431
Author(s):  
José M Enciso ◽  
Kristine B Gutzkow ◽  
Gunnar Brunborg ◽  
Ann-Karin Olsen ◽  
Adela López de Cerain ◽  
...  
Keyword(s):  
Dna Damage ◽  
Comet Assay ◽  
X Rays ◽  
Solution Composition ◽  
Lysis Time

scholarly journals Analysis of Sensitometry in Radiographic Films using Optical Density Measurement

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Oladotun A. Ojo ◽  
Peter A. Oluwafisoye ◽  
Charles O. Chime
Keyword(s):  
Quality Control ◽  
Optical Density ◽  
Density Measurement ◽  
Absorbed Dose ◽  
Good Prediction ◽  
Radiographic Film ◽  
X Ray ◽  
Dose Curve ◽  
Optical Density Measurement ◽  
Before And After

The sensitivity of radiographic films is an important factor to the clarity and accuracy of X-ray exposure to patients during treatment or diagnostic periods. It is therefore important to do a thorough analysis of the sensitivity of the radiographic film before and after exposure to enhance the Quality Assurance (QA) and the Quality Control (QC), of the exposure procedures. The optical densities (OD) of each film was measured, with a densitometer model MA 5336, made by GAMMEX. These values were then converted to the absorbed dose (X mGy), which is the amount of dose absorbed by each patient. The optical density versus the dose curve, followed the expected pattern, showing a good prediction from the General model, that the films employed in the exposures were of good quality and standard. Hence the optical density versus dose sensitometric curves depicts the outcome of the various films sensitivity after an exposure to the X-ray radiation through the patients.

Preliminary Study on the Anti-radiation Effect of Jen-Sheng-Yang-Yung-Tang

1993 ◽  
Vol 21 (02) ◽  
pp. 187-195 ◽  
Author(s):  
Hsue-yin Hsu ◽  
Yau-hui Ho ◽  
Shi-Iong Lian ◽  
Chun-ching Lin
Keyword(s):  
Bone Marrow ◽  
Radiation Effect ◽  
Bone Marrow Cells ◽  
X Rays ◽  
Male Mice ◽  
X Ray ◽  
Colony Forming Units ◽  
Before And After ◽  
Preliminary Study ◽  
Different Doses

Six to seven week old male mice of ICR strain were exposed to different doses of x-rays to determine if Jen-Sheng-Yang-Yung-Tang could be a modifier in the elimination of radiation damage. Colony forming units of bone marrow cells in the spleen (CFUs) were measured before and after x-ray irradiation with intraperitoneal injection of 10 mg/20 g or 20 mg/20 g body weight of Jen-Sheng-Yang-Yung-Tang, once a day for seven consecutive days. The recovery of CFUs and hemocytes counts by 4 Gy irradiation with Jen-Sheng-Yang-Yung-Tang administration was faster for a concentration of 20 mg/20 g than 10 mg/20 g. The measurement of 10-day CFUs showed an increase of radiotolerance in the treatment of 20 mg/20 g administration before x-ray irradiation. The injection of Jen-Sheng-Yang-Yung-Tang accelerated the recovery of hemocyte counts in mice irradiated with 4 Gy x-ray; the effect was especially profound for leukocytes with 20 mg/20 g Jen-Sheng-Yang-Yung-Tang administration after irradiation.

Cytogenetic Damage of Human Lymphocytes in Humanized Mice Exposed to Neutrons and X Rays 24 h After Exposure

2021 ◽  
Vol 161 (6-7) ◽  
pp. 352-361
Author(s):  
Qi Wang ◽  
Younghyun Lee ◽  
Monica Pujol-Canadell ◽  
Jay R. Perrier ◽  
Lubomir Smilenov ◽  
...  
Keyword(s):  
Dna Damage ◽  
Radiation Exposure ◽  
Human Lymphocytes ◽  
Absorbed Dose ◽  
Chromosome 1 ◽  
X Rays ◽  
Chromosomal Dna ◽  
Humanized Mouse Model ◽  
Significant Difference

Detonation of an improvised nuclear device highlights the need to understand the risk of mixed radiation exposure as prompt radiation exposure could produce significant neutron and gamma exposures. Although the neutron component may be a relatively small percentage of the total absorbed dose, the large relative biological effectiveness (RBE) can induce larger biological DNA damage and cell killing. The objective of this study was to use a hematopoietically humanized mouse model to measure chromosomal DNA damage in human lymphocytes 24 h after in vivo exposure to neutrons (0.3 Gy) and X rays (1 Gy). The human dicentric and cytokinesis-block micronucleus assays were performed to measure chromosomal aberrations in human lymphocytes in vivo from the blood and spleen, respectively. The mBAND assay based on fluorescent in situ hybridization labeling was used to detect neutron-induced chromosome 1 inversions in the blood lymphocytes of the neutron-irradiated mice. Cytogenetics endpoints, dicentrics and micronuclei showed that there was no significant difference in yields between the 2 irradiation types at the doses tested, indicating that neutron-induced chromosomal DNA damage in vivo was more biologically effective (RBE ∼3.3) compared to X rays. The mBAND assay, which is considered a specific biomarker of high-LET neutron exposure, confirmed the presence of clustered DNA damage in the neutron-irradiated mice but not in the X-irradiated mice, 24 h after exposure.

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