Shahid Beheshti University of Medical Sciences and Health Services

About: Shahid Beheshti University of Medical Sciences and Health Services is a education organization based out in Tehran, Iran. It is known for research contribution in the topics: Population & Medicine. The organization has 19456 authors who have published 33659 publications receiving 365676 citations.

RNA-mediated epigenetic heredity requires the cytosine methyltransferase Dnmt2.

Abstract: RNA–mediated transmission of phenotypes is an important way to explain non-Mendelian heredity. We have previously shown that small non-coding RNAs can induce hereditary epigenetic variations in mice and act as the transgenerational signalling molecules. Two prominent examples for these paramutations include the epigenetic modulation of the Kit gene, resulting in altered fur coloration, and the modulation of the Sox9 gene, resulting in an overgrowth phenotype. We now report that expression of the Dnmt2 RNA methyltransferase is required for the establishment and hereditary maintenance of both paramutations. Our data show that the Kit paramutant phenotype was not transmitted to the progeny of Dnmt2−/− mice and that the Sox9 paramutation was also not established in Dnmt2−/− embryos. Similarly, RNA from Dnmt2-negative Kit heterozygotes did not induce the paramutant phenotype when microinjected into Dnmt2-deficient fertilized eggs and microinjection of the miR-124 microRNA failed to induce the characteristic giant phenotype. In agreement with an RNA–mediated mechanism of inheritance, no change was observed in the DNA methylation profiles of the Kit locus between the wild-type and paramutant mice. RNA bisulfite sequencing confirmed Dnmt2-dependent tRNA methylation in mouse sperm and also indicated Dnmt2-dependent cytosine methylation in Kit RNA in paramutant embryos. Together, these findings uncover a novel function of Dnmt2 in RNA–mediated epigenetic heredity.

Sensory analysis: relevance for prebiotic, probiotic, and synbiotic product development.

Abstract: Sensory analysis represents a decisive step during the various stages of food product development. For probiotic, prebiotic, and synbiotic foods, which have shown continuous and significant consumption in the functional food category, the choice of an appropriate technique allows obtaining relevant sensory information that contributes to consumer acceptance. This review focuses on the importance of sensory analytical techniques in prebiotic and probiotic food product development. Examples of the most known sensory methodologies applied to these important functional foods are presented, as well as some considerations about consumer attitudes that can influence acceptance of these products. Moreover, applications of such techniques on functional product evaluation are provided.

Breastfeeding and maternal and infant iodine nutrition

Abstract: Summary Objective The aim of this review is to explore information available regarding iodine secretion in milk, both mothers and infants iodine nutrition during breastfeeding and to make recommendations for appropriate iodine supplementation during lactation. Design MEDLINE was queried for studies between 1960 and 2007 that included lactation and breastfeeding with iodine and iodine deficiency. Studies were selected if they studied (i) Secretion of iodine in breast milk; (ii) breastfeeding and iodine nutrition; (iii) factors affecting maternal iodine metabolism and (iv) recommendations for iodine supplementation during breastfeeding. Results Thirty-six articles met the selection criteria. The iodine content of breast milk varies with dietary iodine intake, being lowest in areas of iodine deficiency with high prevalence of goitre. Milk iodine levels are correspondingly higher when programs of iodine prophylaxis such as salt iodization or administration of iodized oil have been introduced. The small iodine pool of the neonatal thyroid turns over very rapidly and is highly sensitive to variations in dietary iodine intake. Expression of the sodium iodide symporter is up-regulated in the lactating mammary gland which results in preferential uptake of iodide. In areas of iodine sufficiency breast milk iodine concentration should be in the range of 100–150 µg/dl. Studies from France, Germany, Belgium, Sweden, Spain, Italy, Denmark, Thailand and Zaire have shown breast milk concentrations of < 100 µg/l. Adequate levels of iodine in breast milk have been reported from Iran, China, USA and some parts of Europe. Conclusions Adequate concentration of iodine in breast milk is essential to provide for optimal neonatal thyroid hormone stores and to prevent impaired neurological development in breast-fed neonates. In many countries of the world, low iodine content of the breast milk indicates less than optimum maternal and infant iodine nutrition. The current WHO/ICCIDD/UNICEF recommendation for daily iodine intake (250 µg for lactating mothers) has been selected to ensure that iodine deficiency dose not occur in the postpartum period and that the iodine content of the milk is sufficient for the infant's iodine requirement.

Food insecurity and mental health: a systematic review and meta-analysis.

Abstract: Objective Food security has been suggested to be a risk factor for depression, stress and anxiety. We therefore undertook a systematic review and meta-analysis of available publications to examine these associations further. Design Relevant studies were identified by searching Web of Science, Embase, Scopus and PubMed databases up to January 2019. Setting OR was pooled using a random-effects model. Standard methods were used for assessment of heterogeneity and publication bias. Participants Data were available from nineteen studies with 372 143 individual participants from ten different countries that were pooled for the meta-analysis. Results The results showed there was a positive relationship between food insecurity (FI) and risk of depression (OR = 1·40; 95 % CI: 1·30, 1·58) and stress (OR = 1·34; 95 % CI: 1·24, 1·44) but not anxiety. Subgroup analysis by age showed that subjects older than ≥65 years exhibited a higher risk of depression (OR = 1·75; 95 % CI: 1·20, 2·56) than younger participants (OR = 1·34; 95 % CI: 1·20, 1·50), as well as a greater risk of depression in men (OR = 1·42; 95 % CI: 1·17, 1·72) than women (OR = 1·30; 95 % CI: 1·16, 1·46). Finally, subgroup analysis according to geographical location illustrated that food insecure households living in North America had the highest risk of stress and anxiety. Conclusions The evidence from this meta-analysis suggests that FI has a significant effect on the likelihood of being stressed or depressed. This indicates that health care services, which alleviate FI, would also promote holistic well-being in adults.