Influence of folate status on genomic DNA methylation in colonic mucosa of subjects without colorectal adenoma or cancer

DNA hypomethylation may increase the risk of colorectal cancer. The main aim of this study was to assess the influence of folate status (serum and erythrocyte folate and plasma homocysteine concentrations) on DNA methylation. Methylenetetrahydrofolate reductase (MTHFR 677C → T and 1298A → C), methionine synthase (MS 2756A → G) and cystathionine synthase (CBS 844ins68) polymorphisms were measured to account for potential confounding effects on folate status and DNA methylation. A total of 68 subjects (33 men and 35 women, 36–78 years) free from colorectal polyps or cancer were recruited in a cross-sectional study. Tissue biopsies were obtained at colonoscopy for the determination of DNA methylation in colonic mucosa using an in vitro radiolabelled methyl acceptance assay. Serum and erythrocyte folate were inversely correlated with plasma homocysteine (r=−0.573, P<0.001 and r=−0.307, P=0.01 respectively) and DNA hypomethylation in colonic mucosa (r=−0.311, P=0.01 and r=−0.356, P=0.03). After adjusting for gender, age, body mass index, smoking and genotype, there were weak negative associations between serum and erythrocyte folate and colonic DNA hypomethylation (P=0.07 and P=0.08, respectively)

Sensitivity of markers of DNA stability and DNA repair activity to folate supplementation in healthy volunteers

We have previously reported that supplementation with folic acid (1.2 mg day−1 for 12 week) elicited a significant improvement in the folate status of 61 healthy volunteers. We have examined effects of this supplement on markers of genomic stability. Little is known about the effect of folate supplementation on DNA stability in a cohort, which is not folate deficient. Preintervention, there was a significant inverse association between uracil misincorporation in lymphocyte DNA and red cell folate (P<0.05). In contrast, there were no associations between folate status and DNA strand breakage, global DNA methylation or DNA base excision repair (measured as the capacity of the lymphocyte extract to repair 8-oxoGua ex vivo). Folate supplementation elicited a significant reduction in uracil misincorporation (P<0.05), while DNA strand breakage and global DNA methylation remained unchanged. Increasing folate status significantly decreased the base excision repair capacity in those volunteers with the lowest preintervention folate status (P<0.05). Uracil misincorporation was more sensitive to changes in folate status than other measures of DNA stability and therefore could be considered a specific and functional marker of folate status, which may also be relevant to cancer risk in healthy people

Photobiological hydrogen production and artificial photosynthesis for clean energy: from bio to nanotechnologies

Global energy demand is increasing rapidly and due to intensive consumption of different forms of fuels, there are increasing concerns over the reduction in readily available conventional energy resources. Because of the deleterious atmospheric effects of fossil fuels and the uncertainties of future energy supplies, there is a surge of interest to find environmentally friendly alternative energy sources. Hydrogen (H2) has attracted worldwide attention as a secondary energy carrier, since it is the lightest carbon-neutral fuel rich in energy per unit mass and easy to store. Several methods and technologies have been developed for H2 production, but none of them are able to replace the traditional combustion fuel used in automobiles so far. Extensively modified and renovated methods and technologies are required to introduce H2 as an alternative efficient, clean, and cost-effective future fuel. Among several emerging renewable energy technologies, photobiological H2 production by oxygenic photosynthetic microbes such as green algae and cyanobacteria or by artificial photosynthesis has attracted significant interest. In this short review, we summarize the recent progress and challenges in H2-based energy production by means of biological and artificial photosynthesis routes. © 2015 Springer Science+Business Media Dordrecht.

Le Don De Corps En Cote D\'ivoire

Introduction Le don de corps qui permet de se procurer le matériel anatomique de dissection que constitue le cadavre humain n\'existe pas en Afrique noire et notamment en Cote d\' Ivoire. Objectif Recueillir des informations sur le don de corps à Abidjan. Méthode Les auteurs rapportent les informations recueillies au cours dune enquête sur le don de corps réalisée à Abidjan de Juillet a Août 2004, a partir d\'un questionnaire. Ils font une analyse anthropologique de ces informations et situent la position des abidjanais sur la recherche médicale à travers les dissections anatomiques du corps humain. Résultats Il ressort de cette enquête que 35,8 % des abidjanais sont prêts à donner leur corps, 64,2 % sont contre le don de corps. Conclusion 35,8 % des abidjanais peuvent contribuer au progrès de la médecine en donnant leur corps à disséquer après leur mort même si cette décision reste difficile en Afrique compte tenu du culte des morts. Background The concept of body donation for dissection does not exist in black Africa particularly in the Ivory Coast. Objective Collect informations on body donation in Abidjan. Methods Authors report information collected in Abidjan during survey on body donation, carry out from July to August 2004. They make an anthropological analysis of that information and indicate the position of the inhabitants of Abidjan on the research through anatomic human bodies\' dissection. Results Our survey shows that 35.8% of the inhabitants of Abidjan agreed to make a body donation for dissection against 64.2 %. Conclusion 35.8 % of the inhabitants of Abidjan can contribute to the ptogress of medicine by offering their body for dissection after death even if this decision remains difficult in Africa considering deeds worship. Keywords: Anatomy, body donation, Ivory coast, AfricaAfrican Journal of Neurological Sciences Vol. 25 (1) 2006: pp. 5-1