H2AX phosphorylation screen of cells from radiosensitive cancer patients reveals a novel DNA double-strand break repair cellular phenotype

BACKGROUND: About 1-5% of cancer patients suffer from significant normal tissue reactions as a result of radiotherapy (RT). It is not possible at this time to predict how most patients' normal tissues will respond to RT. DNA repair dysfunction is implicated in sensitivity to RT particularly in genes that mediate the repair of DNA double-strand breaks (DSBs). Phosphorylation of histone H2AX (phosphorylated molecules are known as gammaH2AX) occurs rapidly in response to DNA DSBs, and, among its other roles, contributes to repair protein recruitment to these damaged sites. Mammalian cell lines have also been crucial in facilitating the successful cloning of many DNA DSB repair genes; yet, very few mutant cell lines exist for non-syndromic clinical radiosensitivity (RS).\ud \ud METHODS: Here, we survey DNA DSB induction and repair in whole cells from RS patients, as revealed by gammaH2AX foci assays, as potential predictive markers of clinical radiation response.\ud \ud RESULTS: With one exception, both DNA focus induction and repair in cell lines from RS patients were comparable with controls. Using gammaH2AX foci assays, we identified a RS cancer patient cell line with a novel ionising radiation-induced DNA DSB repair defect; these data were confirmed by an independent DNA DSB repair assay.\ud \ud CONCLUSION: gammaH2AX focus measurement has limited scope as a pre-RT predictive assay in lymphoblast cell lines from RT patients; however, the assay can successfully identify novel DNA DSB repair-defective patient cell lines, thus potentially facilitating the discovery of novel constitutional contributions to clinical RS

Comparative Study: Physico-Chemical Properties of Virgin Coconut Oil Using Various Culture

Using various culture to produce Virgin Coconut Oil (VCO) by applied fermentation methods are important aspect impacted on characteristic of VCO. The objective of this research is to investigate the physico-chemical properties of VCO produced by various culture. The cultures were used in fermentation methods are Saccharomyces cerevisiae, Lactobacillus plantarum, and Rhizopus oligosporus. Research activities were conducted in two stages; the first stage was the production of VCO by fermentation at 35oC for 24 hours. Then, physico-chemical properties of products were analyzed using standart methods. Results showed that moisture content, acid number and iodine number of VCO produced using Saccharomyces cerevisiae lower than others. Density, viscosity and peroxide number has almost the same value. Nevertheless, all of physico-chemical properties conform to the Asian and Pacific Coconut Community (APCC) and Standar Nasional Indonesia for VCO product.Keywords— culture, fermentation, physico-chemical properties, quality, Virgin Coconut Oil