Recent preclinical studies have suggested that radiotherapy in combination with antiangiogenic/vasculature targeting agents enhances the therapeutic ratio of ionizing radiation alone. Because radiotherapy is one of the most widely used treatments for cancer, it is important to understand how best to use these two modalities to aid in the design of rational patient protocols. The mechanisms of i...

OBJECTIVE To determine population-based rates of the use of diagnostic imaging procedures with ionizing radiation in children, stratified by age and sex. DESIGN Retrospective cohort analysis. SETTING All settings using imaging procedures with ionizing radiation. PATIENTS Individuals younger than 18 years, alive, and continuously enrolled in UnitedHealthcare between January 1, 2005, and De...

Humic substances, i.e. dark paramagnetic polymeric anionic polyelectrolytes, belong to the most widespread macromolecular substances of biogenic origin in soil and aquatic environments. The exact structure of humic substances is unknown because of their complexity resulting from unrecurring precursors, from their composition and their process of synthesis. Degradation processes of these substan...

Loss of p53 function has been shown to cause increased resistance to ionizing radiation in normal murine cells; however, the role of p53 in radioresistance of human tumor cells is less clear. Since wild-type p53 function is required for radiation-induced G1 arrest, we measured G1 arrest in 12 human tumor cell lines that have a wide range of radiosensitivities (surviving fraction at 2 Gy, 0.11-0...

The BRCA1 tumor suppressor contributes to the repair of DNA double-strand breaks (DSB) through homologous recombination, but the mechanism is unknown. The rapid accumulation of BRCA1 into nuclear foci in response to induction of DNA breaks suggests that BRCA1 may function in an early step in the repair pathway. We examined the role of BRCA1 in one such early step, the resection of DSBs to gener...

Different types of ionizing radiation produce different dependences of cancer risk on radiation dose/dose rate. Sparsely ionizing radiation (e.g. γ-rays) generally produces linear or upwardly curving dose responses at low doses, and the risk decreases when the dose rate is reduced (direct dose rate effect). Densely ionizing radiation (e.g. neutrons) often produces downwardly curving dose respon...

Modern medicine cannot exist without diagnostic and therapeutic methods that are based on ionizing radiation. Therefore it is necessary to understand interactions between this form of energy living matter make a full use progress in radiobiology. Ionizing radiation widely used for relatively long time, how known, disproportionately huge doses particularly harmful organisms including humans. How...

snm1 mutants of Saccharomyces cerevisiae have been shown to be specifically sensitive to DNA interstrand crosslinking agents but not sensitive to monofunctional alkylating agents, UV, or ionizing radiation. Five homologs of SNM1 have been identified in the mammalian genome and are termed SNM1, SNM1B, Artemis, ELAC2, and CPSF73. To explore the functional role of human Snm1 in response to DNA dam...

Differentiation-induction therapy is an attractive approach in leukemia treatment. It has been suggested that the accumulation of intracellular reactive oxygen species (ROS) is involved in megakaryocytic differentiation induced by phorbol 12-myristate 13-acetate (PMA) in the K562 leukemia cell line. Therefore, a ROS-inducible technique could be a powerful method of differentiation induction. Ac...

We use a wide-field (0.9 deg) X-ray sample with optical and GALEX ultraviolet observations to measure the contribution of Active Galactic Nuclei (AGNs) to the ionizing flux as a function of redshift. Our analysis shows that the AGN contribution to the metagalactic ionizing background peaks at around z = 2. The measured values of the ionizing background from the AGNs are lower than previous esti...