OBJECTIVE Glioblastoma multiforme (GBM), one of the most common and aggressive malignant brain tumors, is highly resistant to radiotherapy. Numerous approaches have been pursued to find new radiosensitizers. We used a picogreen and colonogenic assay to appraise the DNA damage and cell death in a spheroid culture of GBM cells caused by iodine-131 (I-131) beta radiation in the presence of topotec...

In this work, the chemical changes in calf thymus DNA samples were analyzed by X-ray photoelectron spectroscopy (XPS). The DNA samples were irradiated for over 5 h and spectra were taken repeatedly every 30 min. In this approach the X-ray beam both damages and probes the samples. In most cases, XPS spectra have complex shapes due to contributions of C, N, and O atoms bonded at several different...

and singlet oxygen. ROS is also generated in cells by exposure to radiation and chemical carcinogens, Because ROS damages nearby cellular components such as DNA, proteins and lipids in mernbrane, cells must have evolved multiple defense mechanisms to combat the oxidative stress, Enzymes such as catalase or superoxide dismutase detoxify ROS, and low-molecular-weight scavengers such as glutathion...

crude oil is enriched in polycyclic aromatic hydrocarbons (pahs). many pah analogs have proved to potentially damage dna. dna damage can be assessed using various biomarkers to find out the degree of genotoxicity of pollutants following in vitro exposure. in this research the comet assay and micronucleus (mn) test were used to detect dna damages and cytogenetic changes following crude oil expos...

Ultraviolet light damages DNA by converting two adjacent thymines into a thymine dimer which is potentially mutagenic, carcinogenic, or lethal to the organism. This damage is repaired by photolyase and the nucleotide excision repair system in E. coli by nucleotide excision repair in humans. The work leading to these results is presented by Aziz Sancar in his Nobel Lecture.

Although heavy metals are naturally occurring elements that found throughout the Earth’s crust, most environmental contamination and human exposure result from anthropogenic activities, such as mining smelting operations, industrial production use, domestic agricultural use of metal-containing compounds. The accumulation eventually produces reactive oxygen species can cause oxidative stress, wh...

background: stress may cause damages to dna or/and change the ability of the cells to overcome these damages. it may also cause irregularities in the cell cycle and induce abnormal cell divisions through glucocorticoid-dependent functions. the abnormal cell divisions, in turn, lead to chromosomal mal-segregation and aneuploidy. in this study, the effects of the stress hormone, hydrocortisone (h...