Radiation adverse outcome pathways (AOPs) are on the horizon: advancing radiation protection through an international Horizon-Style exercise.

Purpose: The Adverse Outcome Pathway (AOP) framework, a systematic tool that can link available mechanistic data with phenotypic outcomes of relevance to regulatory decision-making, is being explored in areas related to radiation risk assessment. To examine the challenges including the use of AOPs to support the radiation protection community, an international horizon-style exercise was initiated through the Organisation for Economic Co-operation and Development Nuclear Energy Agency High-Level Group on Low Dose Research Radiation/Chemical AOP Joint Topical Group. The objective of the HSE was to facilitate the collection of ideas from a range of experts, to short-list a set of priority research questions that could, if answered, improve the description of the radiation dose-response relationship for low dose/dose-rate exposures, as well as reduce uncertainties in estimating the risk of developing adverse health outcomes following such exposures.

Low-dose radiation research and radiation protection policy implementation at the Department of Energy.

One of the Department of Energy's (DOE) highest priorities is the protection of workers, the public and the environment from the conduct of DOE activities. As a self-regulating agency, DOE develops radiation protection policies and orders that integrate national and international consensus standards into requirements that enable it to complete its diverse missions safely and effectively. DOE leadership is unequivocally committed to the well-being of its workforce involved in carrying out its mission.

Workshop Report on Atomic Bomb Dosimetry--Review of Dose Related Factors for the Evaluation of Exposures to Residual Radiation at Hiroshima and Nagasaki.

Groups of Japanese and American scientists, supported by international collaborators, have worked for many years to ensure the accuracy of the radiation dosimetry used in studies of health effects in the Japanese atomic bomb survivors. Reliable dosimetric models and systems are especially critical to epidemiologic studies of this population because of their importance in the development of worldwide radiation protection standards. While dosimetry systems, such as Dosimetry System 1986 (DS86) and Dosimetry System 2002 (DS02), have improved, the research groups that developed them were unable to propose or confirm an additional contribution by residual radiation to the survivor's total body dose.

Workshop report on atomic bomb dosimetry-residual radiation exposure: recent research and suggestions for future studies.

There is a need for accurate dosimetry for studies of health effects in the Japanese atomic bomb survivors because of the important role that these studies play in worldwide radiation protection standards. International experts have developed dosimetry systems, such as the Dosimetry System 2002 (DS02), which assess the initial radiation exposure to gamma rays and neutrons but only briefly consider the possibility of some minimal contribution to the total body dose by residual radiation exposure. In recognition of the need for an up-to-date review of the topic of residual radiation exposure in Hiroshima and Nagasaki, recently reported studies were reviewed at a technical session at the 57th Annual Meeting of the Health Physics Society in Sacramento, California, 22-26 July 2012.

Molecular characterization of Syrian date palm cultivars using plasmid-like DNA markers.

Date palm (Phoenix dactylifera L.) is one of the most important domesticated fruit trees in the Near East and North African countries. This tree has been, for several decades, in serious threat of being completely destroyed by the "Bayoud" disease caused by Fusarium oxysporum f.

Identification of meat species by PCR-RFLP of the mitochondrial COI gene.

Meat authenticity verification is pertinent for economical, religious or public health concerns. The present study investigates the use of PCR-RFLP of a part of the mitochondrial cytochrome c oxidase subunit 1 (COI) gene for identification of species origin of raw meat samples of cow, chicken, turkey, sheep, pig, buffalo, camel and donkey. PCR yielded a 710-bp fragment in all species.

The genus Crataegus L.: an ecological and molecular study.

This study aimed at the indentification of the species and genotypes of the genus Crataegus in Syria and determination of the genetic relationships among them based on the analysis of genomic and chloroplast DNA (cpDNA) using ISSRs and CAPS techniques. Morphological characterization carried out on 49 Crataegus samples collected from different geographical regions of Syria revealed four Crataegus species: C. monogyna, C.

Identification of Orchidaceae species from Northern West of Syria based on chloroplast DNA.

The plant family Orchidaceae has a great economic value (ornamental and medical uses, beside the aromatic features). Traditionally, identification of orchid species has relied heavily on morphological features. These features, however, are either not variable enough between species or too plastic to be used for identification at the species level.

Radiation-induced DNA damage in tumors and normal tissues. VI. Estimation of the hypoxic fraction of experimental tumors.

For several years, we have concentrated our efforts on validating the use of radiation-induced DNA strand breaks and DNA-protein crosslinks to assess the oxygenation status of tumors and normal tissues. We have demonstrated that (1) the oxygen dependence of strand break formation is identical to that of radiation-induced cell killing; (2) the oxygen dependence of DNA-protein crosslink formation is the mirror image of that of radiation-induced cell killing; and (3) the formation of these radiation-induced DNA lesions is predominantly dependent on the oxygen concentration near the DNA and is independent of the cell type, metabolic status, proliferative status, pH of the surrounding environment, and composition or properties of the proteins tightly associated with the DNA. In the present study, the hypoxic fraction of three experimental tumors was estimated using our assay of radiation-induced DNA damage.

Effect of ploidy, recruitment, environmental factors, and tamoxifen treatment on the expression of sigma-2 receptors in proliferating and quiescent tumour cells.

Recently, we demonstrated that sigma-2 receptors may have the potential to be a biomarker of tumour cell proliferation (Mach et al (1997) Cancer Res 57: 156-161). If sigma-2 receptors were a biomarker of tumour cell proliferation, they would be amenable to detection by non-invasive imaging procedures, thus eliminating many of the problems associated with the flow cytometric measures of tumour cell proliferation presently used in the clinic. To be a good biomarker of tumour cell proliferation, the expression of sigma-2 receptors must be essentially independent of many of the biological, physiological, and/or environmental properties that are found in solid tumours.

Radiation-induced DNA damage in tumors and normal tissues: V. Influence of pH and nutrient depletion on the formation of DNA-protein crosslinks in irradiated partially and fully hypoxic tumor cells.

It has been demonstrated that the yield of radiation-induced DNA strand breaks and DNA-protein crosslinks (DPCs) appears to depend predominantly on the oxygen concentration in the microenvironment around the DNA of mammalian cells (Radiat. Res. 142, 163-168, 1995).

Temperature dependence of radiation-induced DNA-protein crosslinks formed under hypoxic conditions.

Recently, we demonstrated that the oxygen dependence of the formation of DNA-protein crosslinks (DPCs) in irradiated mammalian cells measured by the alkaline elution technique is the mirror image of the oxygen dependence of radiation-induced cell killing. Consequently, these radiation-induced DPCs could be used to detect hypoxic cells or estimate the hypoxic fraction of cells in solid tumors. Although several techniques, including alkaline elution, gas chromatography/mass spectrometry (GC/MS) and nitrocellulose filter binding, have been used to measure radiation-induced DPCs, the published reports suggest that the characteristics of these DPCs may depend on both the type of sample irradiated (cellular compared to model systems, oxygenated compared to hypoxic, etc.

Sigma 2 receptors as potential biomarkers of proliferation in breast cancer.

sigma 1 and sigma 2 receptors have been shown to exist in a number of rodent and human tumor cell lines. Although their expression is heterogeneous and their function is unknown, sigma receptors have been proposed as potential targets for diagnostic tumor-imaging agents. In this study, the density of sigma 2 receptors in proliferative (P) and quiescent (Q) cells of the mouse mammary adenocarcinoma, line 66, was examined.

Expression of thymidine kinase is essential to low dose radiation resistance of rat glioma cells.

We have found that thymidine kinase expression is a major radioresponse determinant in rat glioma cells. Cells that lack thymidine kinase expression are significantly more radiosensitive relative to the wild-type cells. The degree of sensitization is large, particularly at the dose levels used in fractionated radiotherapy.

Effect of L-buthionine sulfoximine on the radiation response of human renal carcinoma cell lines.

Background: Renal cell carcinoma (RCC) is a progressive and relatively radioresistant disease. Currently, no data are available on the in vitro radiobiologic characterization of renal tumor cells to the authors' knowledge.

Methods: Two RCC were cultured from specimens from previously untreated patients after either surgical resection of the primary tumor or from the malignant ascites.

Photosensitization of MCF-7 cells with diaziquone using visible light: correlation with DNA strand breaks and free radical production.

The ability of visible light to enhance the activity of diaziquone (AZQ) was evaluated in MCF-7 human breast cancer cells. MCF-7 cells were sensitive to AZQ, while visible light illumination had no appreciable effect on cell survival. In the presence of AZQ, visible light potentiated AZQ's cytotoxicity.