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Certain Nutrients (certain + nutrient)
Selected AbstractsEtiology, pathogenesis and prevention of neural tube defectsCONGENITAL ANOMALIES, Issue 2 2006Rengasamy Padmanabhan ABSTRACT Spina bifida, anencephaly, and encephalocele are commonly grouped together and termed neural tube defects (NTD). Failure of closure of the neural tube during development results in anencephaly or spina bifida aperta but encephaloceles are possibly post-closure defects. NTD are associated with a number of other central nervous system (CNS) and non-neural malformations. Racial, geographic and seasonal variations seem to affect their incidence. Etiology of NTD is unknown. Most of the non-syndromic NTD are of multifactorial origin. Recent in vitro and in vivo studies have highlighted the molecular mechanisms of neurulation in vertebrates but the morphologic development of human neural tube is poorly understood. A multisite closure theory, extrapolated directly from mouse experiments highlighted the clinical relevance of closure mechanisms to human NTD. Animal models, such as circle tail, curly tail, loop tail, shrm and numerous knockouts provide some insight into the mechanisms of NTD. Also available in the literature are a plethora of chemically induced preclosure and a few post-closure models of NTD, which highlight the fact that CNS malformations are of hetergeneitic nature. No Mendelian pattern of inheritance has been reported. Association with single gene defects, enhanced recurrence risk among siblings, and a higher frequency in twins than in singletons indicate the presence of a strong genetic contribution to the etiology of NTD. Non-availability of families with a significant number of NTD cases makes research into genetic causation of NTD difficult. Case reports and epidemiologic studies have implicated a number of chemicals, widely differing therapeutic drugs, environmental contaminants, pollutants, infectious agents, and solvents. Maternal hyperthermia, use of valproate by epileptic women during pregnancy, deficiency and excess of certain nutrients and chronic maternal diseases (e.g. diabetes mellitus) are reported to cause a manifold increase in the incidence of NTD. A host of suspected teratogens are also available in the literature. The UK and Hungarian studies showed that periconceptional supplementation of women with folate (FA) reduces significantly both the first occurrence and recurrence of NTD in the offspring. This led to mandatory periconceptional FA supplementation in a number of countries. Encouraged by the results of clinical studies, numerous laboratory investigations focused on the genes involved in the FA, vitamin B12 and homocysteine metabolism during neural tube development. As of today no clinical or experimental study has provided unequivocal evidence for a definitive role for any of these genes in the causation of NTD suggesting that a multitude of genes, growth factors and receptors interact in controlling neural tube development by yet unknown mechanisms. Future studies must address issues of gene-gene, gene-nutrient and gene,environment interactions in the pathogenesis of NTD. [source] Nutritional supplements, foods, and epilepsy: Is there a relationship?EPILEPSIA, Issue 11 2008Ali A. Asadi-Pooya Summary Anecdotal reports suggest that certain foods and dietary contents might influence the occurrence of seizures. However, the existing data are scanty and sometimes controversial. Some studies have found that the supplementation with individual nutrients reduced seizure frequency or improved other aspects of health in patients with epilepsy, while other studies have failed to confirm those findings. Nutrient supplementation may be necessary to prevent or reverse the effects of certain deficiencies that frequently result from the use of antiepileptic drugs (AEDs). However, the potential benefits of nutrient supplementation in patients with epilepsy must be weighed against reports that large doses of certain nutrients can interfere with the action of some AEDs. This paper reviews dietary and nutritional considerations in patients with epilepsy and also the relationship between foods, dietary elements, and seizures. [source] Saccharomyces cerevisiae plasma membrane nutrient sensors and their role in PKA signalingFEMS YEAST RESEARCH, Issue 2 2010Marta Rubio-Texeira Abstract The ability to elicit a fast intracellular signal leading to an adaptive response is crucial for the survival of microorganisms in response to changing environmental conditions. Therefore, in order to sense changes in nutrient availability, the yeast Saccharomyces cerevisiae has evolved three different classes of nutrient-sensing proteins acting at the plasma membrane: G protein-coupled receptors or classical receptor proteins, which detect the presence of certain nutrients and activate signal transduction in association with a G protein; nontransporting transceptors, i.e. nutrient carrier homologues with only a receptor function, previously called nutrient sensors; and transporting transceptors, i.e. active nutrient carriers that combine the functions of a nutrient transporter and receptor. Here, we provide an updated overview of the proteins involved in sensing nutrients for rapid activation of the protein kinase A pathway, which belong to the first and the third category, and we also provide a comparison with the best-known examples of the second category, the nontransporting transceptors, which control the expression of the regular transporters for the nutrient sensed by these proteins. [source] The role of nutrients in modulating diseaseJOURNAL OF SMALL ANIMAL PRACTICE, Issue 6 2008D. L. Chan The role of nutrition in the management of diseases has often centred on correcting apparent nutrient deficiencies or meeting estimated nutritional requirements of patients. Nutrition has traditionally been considered a supportive measure akin to fluid therapy and rarely it has been considered a primary means of ameliorating diseases. Recently, however, further understanding of the underlying mechanisms of various disease processes and how certain nutrients possess pharmacological properties have fuelled an interest in exploring how nutritional therapies themselves could modify the behaviour of various conditions. Nutrients such as omega-3 fatty acids, antioxidants and certain amino acids such as arginine and glutamine have all been demonstrated to have at least the potential to modulate diseases. Developments in the area of critical care nutrition have been particularly exciting as nutritional therapies utilising a combination of approaches have been shown to positively impact outcome beyond simply proving substrate for synthesis and energy. Application of certain nutrients for the modulation of diseases in veterinary patients is still in early stages, but apparent successes have already been demonstrated, and future studies are warranted to establish optimal approaches. This review describes the rationale of many of these approaches and discusses findings both in human beings and in animals, which may guide future therapy. [source] Genetically Engineered Crops: Their Potential Use for Improvement of Human NutritionNUTRITION REVIEWS, Issue 5 2002Lin Yan Ph.D. Great success has been achieved in increasing agriculture productivity to fulfill human needs during the second half of the 20th century. However, there will be much greater challenges in the future. Based on the current population growth rate of 1.4% per year, the world's population is forecast to increase from the current level of approximately six billion to nine to twelve billion in 50 years. In addition to continuously increasing demand for agricultural production, there is an urgent need to improve the nutritional quality of human diets for this rapidly growing human population. Malnutrition is still a worldwide health issue. Macronutrient and micronutrient deficiencies are prevalent in developing countries, and over-consumption of certain nutrients in developed countries (e.g., saturated fatty acids) is associated with high incidence of certain chronic diseases. Furthermore, there will be declining natural resources such as arable land and water, and the challenges to humans must be met without further degrading the environment. Biotechnology offers a valuable tool to help achieve these goals. This review focuses on the most recent advances in biotechnology, which promise to improve human nutrition by enhancing the nutrient density of plant foods. Issues relating to the safety of food products from genetically engineered crops are also discussed. [source] | |||||||||||||