The Role of Telomerase in Radiation-Induced Genomic Instability.

Findings from previous studies have suggested that the telomerase system is involved in radiation-induced genomic instability. In this study, we investigated the involvement of telomerase in the development and processing of chromosomal damage at different cell cycle stages after irradiation of human fibroblasts. Several response criteria were investigated, including cell survival, chromosomal damage (using the micronucleus assay), G-induced chromatid aberrations (using the conventional G assay as well as a chemically-induced premature chromosome condensation assay) and DNA double-strand breaks (DSBs; using γ-H2AX, 53BP1 and Rad51) in an isogenic pair of cell lines: BJ human foreskin fibroblasts and BJ1-hTERT, a telomerase-immortalized BJ cell line.

Dose assessment intercomparisons within the RENEB network using G-lymphocyte prematurely condensed chromosomes (PCC assay).

Purpose: Dose assessment intercomparisons within the RENEB network were performed for triage biodosimetry analyzing G-lymphocyte PCC for harmonization, standardization and optimization of the PCC assay.

Materials And Methods: Comparative analysis among different partners for dose assessment included shipment of PCC-slides and captured images to construct dose-response curves for up to 6 Gy γ-rays. Accident simulation exercises were performed to assess the suitability of the PCC assay by detecting speed of analysis and minimum number of cells required for categorization of potentially exposed individuals.

RENEB biodosimetry intercomparison analyzing translocations by FISH.

Purpose: In the framework of RENEB, several biodosimetry exercises were conducted analyzing different endpoints. Among them, the analysis of translocations is considered the most useful method for retrospective biodosimetry due to the relative stability of their frequency with post irradiation time. The aim of this study was to harmonize the accuracy of translocation-based biodosimetry within the RENEB consortium.

RENEB intercomparison exercises analyzing micronuclei (Cytokinesis-block Micronucleus Assay).

Purpose: In the framework of the 'Realizing the European Network of Biodosimetry' (RENEB) project, two intercomparison exercises were conducted to assess the suitability of an optimized version of the cytokinesis-block micronucleus assay, and to evaluate the capacity of a large laboratory network performing biodosimetry for radiation emergency triages. Twelve European institutions participated in the first exercise, and four non-RENEB labs were added in the second one.

Materials And Methods: Irradiated blood samples were shipped to participating labs, whose task was to culture these samples and provide a blind dose estimate.

Health effects of desalinated water: Role of electrolyte disturbance in cancer development.

This review contends that "healthy" water in terms of electrolyte balance is as important as "pure" water in promoting public health. It considers the growing use of desalination (demineralization) technologies in drinking water treatment which often results in tap water with very low concentrations of sodium, potassium, magnesium and calcium. Ingestion of such water can lead to electrolyte abnormalities marked by hyponatremia, hypokalemia, hypomagnesemia and hypocalcemia which are among the most common and recognizable features in cancer patients.

Verification by the FISH translocation assay of historic doses to Mayak workers from external gamma radiation.

The aim of this study was to apply the fluorescence in situ hybridization (FISH) translocation assay in combination with chromosome painting of peripheral blood lymphocytes for retrospective biological dosimetry of Mayak nuclear power plant workers exposed chronically to external gamma radiation. These data were compared with physical dose estimates based on monitoring with badge dosimeters throughout each person's working life. Chromosome translocation yields for 94 workers of the Mayak production association were measured in three laboratories: Southern Urals Biophysics Institute, Leiden University Medical Center and the former Health Protection Agency of the UK (hereinafter Public Health England).

Causes of genome instability: the effect of low dose chemical exposures in modern society.

Genome instability is a prerequisite for the development of cancer. It occurs when genome maintenance systems fail to safeguard the genome's integrity, whether as a consequence of inherited defects or induced via exposure to environmental agents (chemicals, biological agents and radiation). Thus, genome instability can be defined as an enhanced tendency for the genome to acquire mutations; ranging from changes to the nucleotide sequence to chromosomal gain, rearrangements or loss.

Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.

Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis.

Assessing the applicability of FISH-based prematurely condensed dicentric chromosome assay in triage biodosimetry.

The dicentric chromosome assay (DCA) has been regarded as the gold standard of radiation biodosimetry. The assay, however, requires a 2-d peripheral blood lymphocyte culture before starting metaphase chromosome analyses to estimate biological doses. Other biological assays also have drawbacks with respect to the time needed to obtain dose estimates for rapid decision on the correct line of medical treatment.

Realising the European network of biodosimetry: RENEB-status quo.

Creating a sustainable network in biological and retrospective dosimetry that involves a large number of experienced laboratories throughout the European Union (EU) will significantly improve the accident and emergency response capabilities in case of a large-scale radiological emergency. A well-organised cooperative action involving EU laboratories will offer the best chance for fast and trustworthy dose assessments that are urgently needed in an emergency situation. To this end, the EC supports the establishment of a European network in biological dosimetry (RENEB).

Cytogenetic studies for a group of people living in Japan 1 year after the Fukushima nuclear accident.

In order to understand the potential health effect of radiation from Fukushima nuclear disaster, a group of people living in Japan during and after the accident were investigated 1 y after the accident. The venous blood samples were extracted in tune from 156 tested persons living in Tokyo and Niigata with average age of 42.4 ± 10.

FISH analysis of translocations induced by chronic exposure to Sr radioisotopes: second set of analysis of the Techa River Cohort.

Fluorescent in situ hybridisation analysis of stable translocations was performed for 26 residents living along the Techa River (Russia), who were predominantly (95%) exposed to ingested strontium radioisotopes ((89)Sr and (90)Sr) resulting in exposure of their red bone marrow (RBM). Analysis was conducted at the Urals Research Center for Radiation Medicine, Public Health England and Leiden University Medical Center. Each laboratory scored 1000 cells per donor, which resulted in ∼1000 genome equivalents (GE) per donor.

What radiation dose does the FISH translocation assay measure in cases of incorporated radionuclides for the Southern Urals populations?

The fluorescence in situ hybridisation (FISH) technique is now well established for retrospective dosimetry in cases of external radiation exposure that occurred many years ago. However, the question remains as to whether FISH provides valid estimates of cumulative red bone marrow radiation doses in cases of incorporation of radionuclides or combined external and internal exposures. This question has arisen in connection with the interpretation of results of dose assessments for epidemiological studies of plutonium workers at the Russian Mayak plant and of members of the public exposed to strontium radioisotopes and external radiation as a result of discharges from Mayak to the Techa River.

Metakaryotic stem cell nuclei use pangenomic dsRNA/DNA intermediates in genome replication and segregation.

Bell shaped nuclei of metakaryotic cells double their DNA content during and after symmetric and asymmetric amitotic fissions rather than in the separate, pre-mitotic S-phase of eukaryotic cells. A parsimonious hypothesis was tested that the two anti-parallel strands of each chromatid DNA helix were first segregated as ssDNA-containing complexes into sister nuclei then copied to recreate a dsDNA genome. Metakaryotic nuclei that were treated during amitosis with RNase A and stained with acridine orange or fluorescent antibody to ssDNA revealed large amounts of ssDNA.

Detection and quantification of a radiation-associated mitochondrial DNA deletion by a nested real-time PCR in human peripheral lymphocytes.

In this study we implemented a new assay using a nested real-time polymerase chain reaction (PCR) to detect radiation-induced common deletion (CD) in mitochondrial DNA (mtDNA) of human peripheral lymphocytes. A standard curve for real-time PCR was established by applying a plasmid DNA containing human normal mtDNA or mutated mtDNA. Human peripheral lymphocyte DNA was amplified and quantified by real-time PCR using primer sets for total damaged or mutated mtDNA, plus probes labeled with the fluorescent dyes.

Realising the European Network of Biodosimetry (RENEB).

In Europe, a network for biological dosimetry has been created to strengthen the emergency preparedness and response capabilities in case of a large-scale nuclear accident or radiological emergency. Through the RENEB (Realising the European Network of Biodosimetry) project, 23 experienced laboratories from 16 European countries will establish a sustainable network for rapid, comprehensive and standardised biodosimetry provision that would be urgently required in an emergency situation on European ground. The foundation of the network is formed by five main pillars: (1) the ad hoc operational basis, (2) a basis of future developments, (3) an effective quality-management system, (4) arrangements to guarantee long-term sustainability and (5) awareness of the existence of RENEB.

Preliminary FISH-based assessment of external dose for residents exposed on the Techa River.

This paper presents the results of a feasibility cytogenetic study using the fluorescence in situ hybridization (FISH) translocation assay for residents of villages located on the Techa River (Southern Urals, Russia) contaminated with liquid radioactive wastes from the Mayak plutonium facility in 1949-1956. The study was conducted with two groups of donors that differed in their main pathways of exposure. The first group comprised 18 residents of the middle Techa region who were exposed predominantly from ingestion of radionuclides (mostly (89,90)Sr) via the river water and local foodstuffs.

Potent cytotoxic effects of Calomeria amaranthoides on ovarian cancers.

Background: Ovarian cancer remains the leading cause of death from gynaecological malignancy. More than 60% of the patients are presenting the disease in stage III or IV. In spite of combination of chemotherapy and surgery the prognosis stays poor for therapy regimen.

Review of retrospective dosimetry techniques for external ionising radiation exposures.

The current focus on networking and mutual assistance in the management of radiation accidents or incidents has demonstrated the importance of a joined-up approach in physical and biological dosimetry. To this end, the European Radiation Dosimetry Working Group 10 on 'Retrospective Dosimetry' has been set up by individuals from a wide range of disciplines across Europe. Here, established and emerging dosimetry methods are reviewed, which can be used immediately and retrospectively following external ionising radiation exposure.

Metakaryotic stem cell lineages in organogenesis of humans and other metazoans.

A non-eukaryotic, metakaryotic cell with large, open mouthed, bell shaped nuclei represents an important stem cell lineage in fetal/juvenile organogenesis in humans and rodents. each human bell shaped nucleus contains the diploid human DNA genome as tested by quantitative Feulgen DNA cytometry and fluorescent in situ hybridization with human pan-telomeric, pan-centromeric and chromosome specific probes. From weeks approximately 5-12 of human gestation the bell shaped nuclei are found in organ anlagen enclosed in sarcomeric tubular syncytia.

A novel radiosensitive SCID patient with a pronounced G(2)/M sensitivity.

V(D)J rearrangement in lymphoid cells involves repair of double-strand breaks (DSBs) through non-homologous end joining (NHEJ). Defects in this process lead to increased radiosensitivity and severe combined immunodeficiency (RS-SCID). Here, a SCID patient, M3, is described with a T(-)B(+)NK(+) phenotype but without causative mutations in CD3delta, epsilon, zeta or IL7Ralpha, genes specifically involved in T cell development.

The cellular phenotype of Roberts syndrome fibroblasts as revealed by ectopic expression of ESCO2.

Cohesion between sister chromatids is essential for faithful chromosome segregation. In budding yeast, the acetyltransferase Eco1/Ctf7 establishes cohesion during DNA replication in S phase and in response to DNA double strand breaks in G2/M phase. In humans two Eco1 orthologs exist: ESCO1 and ESCO2.