Evaluation of oxidative stress and genetic instability among residents near mobile phone base stations in Germany.

Human exposure to radiofrequency electromagnetic fields (RF-EMF) is restricted to prevent thermal effects in the tissue. However, at very low intensity exposure "non-thermal" biological effects, like oxidative stress, DNA or chromosomal aberrations, etc. collectively termed genomic-instability can occur after few hours.

Effects of low-dose ionizing radiation on genomic instability in interventional radiology workers.

Interventional radiologists are chronically exposed to low-dose ionizing radiation (IR), which may represent a health risk. The aim of the present study was to evaluate genomic instability by analyzing chromosomal aberrations, micronuclei, and 53BP1 DNA repair foci in peripheral blood lymphocytes of radiologists. Based on the IAEA guidelines on biodosimetry using dicentrics, the average protracted whole-body dose in radiologists were estimated.

Assessment of Individual Radiosensitivity in Breast Cancer Patients Using a Combination of Biomolecular Markers.

About 5% of patients undergoing radiotherapy (RT) develop RT-related side effects. To assess individual radiosensitivity, we collected peripheral blood from breast cancer patients before, during and after the RT, and γH2AX/53BP1 foci, apoptosis, chromosomal aberrations (CAs) and micronuclei (MN) were analyzed and correlated with the healthy tissue side effects assessed by the RTOG/EORTC criteria. The results showed a significantly higher level of γH2AX/53BP1 foci before the RT in radiosensitive (RS) patients in comparison to normal responding patients (NOR).

Chemotherapy and cryopreservation affects DNA repair foci in lymphocytes of breast cancer patients.

Purpose: Although breast cancer (BC) patients benefit from radiotherapy (RT), some radiosensitive (RS) patients suffer from side effects caused by ionizing radiation in healthy tissues. It is thought that RS is underlaid by a deficiency in the repair of DNA double-strand breaks (DSB). DNA repair proteins such as p53-binding protein 1 (53BP1) and phosphorylated histone H2AX (γH2AX), form DNA repair foci at the DSB locations and thus serve as DSB biomarkers.

Imaging flow cytometry and fluorescence microscopy in assessing radiation response in lymphocytes from umbilical cord blood and cancer patients.

DNA double strand breaks (DSB) induced by ionizing radiation (IR) are usually measured using γH2AX/53BP1 DNA repair foci, that is considered to be the most sensitive assay for DSB analysis. While fluorescence microscopy (FM) is the gold standard for this analysis, imaging flow cytometry (IFC) may offer number of advantages such as lack of the fluorescence background, higher number of cells analyzed, and higher sensitivity in detection of DNA damage induced by IR at low doses. Along with appearance of γH2AX foci, the variable fraction of the cells exhibits homogeneously stained γH2AX signal resulting in so-called γH2AX pan-staining, which is believed to appear at early stages of apoptosis.

DNA damage response and apoptosis induced by hyperthermia in human umbilical cord blood lymphocytes.

While hyperthermia (HT) is a promising modality for cancer treatment, the knowledge on mechanisms of its effect on cells is still limited. We have investigated DNA double-strand break (DSB) and apoptosis induced by HT. Umbilical cord blood lymphocytes (UCBL) were subjected to HT at 43 °C.

Effects of different mobile phone UMTS signals on DNA, apoptosis and oxidative stress in human lymphocytes.

Different scientific reports suggested link between exposure to radiofrequency radiation (RF) from mobile communications and induction of reactive oxygen species (ROS) and DNA damage while other studies have not found such a link. However, the available studies are not directly comparable because they were performed at different parameters of exposure, including carrier frequency of RF signal, which was shown to be a critical for appearance of the RF effects. For the first time, we comparatively analyzed genotoxic effects of UMTS signals at different frequency channels used by 3G mobile phones (1923, 1947.

DNA damage response and preleukemic fusion genes induced by ionizing radiation in umbilical cord blood hematopoietic stem cells.

There is clear evidence that ionizing radiation (IR) causes leukemia. For many types of leukemia, the preleukemic fusion genes (PFG), as consequences of DNA damage and chromosomal translocations, occur in hematopoietic stem and progenitor cells (HSPC) in utero and could be detected in umbilical cord blood (UCB) of newborns. However, relatively limited information is available about radiation-induced apoptosis, DNA damage and PFG formation in human HSPC.

Biodosimetry of Low Dose Ionizing Radiation Using DNA Repair Foci in Human Lymphocytes.

Purpose: Ionizing radiation induced foci (IRIF) known also as DNA repair foci represent most sensitive endpoint for assessing DNA double strand breaks (DSB). IRIF are usually visualized and enumerated with the aid of fluorescence microscopy using antibodies to γH2AX and 53BP1. This study analyzed effect of low dose ionizing radiation on residual IRIF in human lymphocytes to the aim of potential biodosimetry and possible extrapolation of high-dose γH2AX/53BP1 effects to low doses and compared kinetics of DSB and IRIF.

Low numbers of pre-leukemic fusion genes are frequently present in umbilical cord blood without affecting DNA damage response.

Despite widely accepted notion that many childhood leukemias are likely developed from hematopoietic stem/progenitor cells (HSPC) with pre-leukemic fusion genes (PFG) formed in embryonic/fetal development, the data on PFG incidence in newborns are contradictive. To provide a better understanding of a prenatal origin of leukemia, umbilical cord blood from 500 newborns was screened for the presence of the most frequent PFG associated with pediatric B-cell acute lymphoblastic leukemia. This screening revealed relatively high incidence of ETV6-RUNX1, BCR-ABL1 (p190) and MLL-AF4 at very low frequencies, averaging ~14 copies per 100,000 cells.

Hematopoietic stem/progenitor cells are less prone to undergo apoptosis than lymphocytes despite similar DNA damage response.

Hematopoietic stem/progenitor CD34+ cells (HSPC) give rise to all types of blood cells and represent a key cellular target for origination of leukemia. Apoptosis and repair of DNA double strand breaks (DSB) are vital processes in leukemogenesis. High doses of ionizing radiation are the best known agent that induces leukemia, but less is known about the leukemogenic potential of low doses.

Validation of JCountPro software for efficient assessment of ionizing radiation-induced foci in human lymphocytes.

Purpose: Ionizing radiation-induced foci (IRIF) known also as DNA repair foci represent the most sensitive and specific assay for assessing DNA double-strand break (DSB). IRIF are usually visualized and enumerated with the aid of fluorescence microscopy using antibodies to phosphorylated γH2AX and 53BP1. Although several approaches and software packages were developed for quantification of IRIF, not one of them was commonly accepted and inter-laboratory variability in the outputs was reported.