View clinical trials related to Night Blindness.
Filter by:The purpose of the study is to determine whether daily consumption of beta-carotene biofortified maize will increase breast milk retinol concentration in lactating Zambian women.
The objectives of this study are: - To evaluate the efficacy of phentolamine mesylate 0.5% and 1.0% ophthalmic solution (Nyxol) in the treatment of night vision complaints, including reduced contrast sensitivity - To evaluate the ocular and systemic safety of phentolamine mesylate 0.5% and 1.0% ophthalmic solution (Nyxol) compared to its vehicle, a sterile, isotonic, buffered aqueous solution containing mannitol and sodium acetate
The purpose of this cluster-randomized trial is to examine whether daily consumption of β-carotene biofortified maize flour can reduce the prevalence of vitamin A deficiency and improve the vitamin A status and among 4-8 year old children in rural Zambia.
The overall aim of the project is to provide proof-of-principle that biofortification of cassava with vitamin A is a viable strategy to improve vitamin A status of deficient populations.
Vitamin A supplementation at birth may increase survival of infants through one year of age by reducing mortality from infectious diseases, though current studies are not conclusive on this point. The goal of our study is to determine if supplementation of newborn infants with 50,000 IU of vitamin A improves aspects of immune function that may be impaired by vitamin A deficiency. Our underlying assumption is that supplementation may thus decrease risk of death by improving immune function and the ability to survive infections. This project will be limited to the examination of the impact of vitamin A on immune function and will not aim to determine the impact on morbidity or mortality, which would require larger sample sizes. The hypotheses addressed by this study are as follows: Provision of vitamin A supplements to newborns at risk of vitamin A deficiency will (1) improve functioning of the thymus (the source of T lymphocytes, cells of the immune system that are important in response to infection and immunization); (2) enhance T lymphocyte-mediated responses to standard vaccines given at birth and early in infancy; and (3) improve gut barrier function (i.e., ability to prevent bacterial infection across the epithelial barrier), relative to provision of a placebo.
Vitamin A deficiency remains a major public health problem in developing country worldwide. Young Children are considered to be at greatest risk of deficiency. However, there is little information on the vitamin A requirement of Chinese children. In the present study, about 400 children aged between 4 and 9 years old in a kindergarten and an elementary school of Shiyan City were screened before admission by questionnaire and anthropometric measurement. The vitamin A status of children was assessed by serum vitamin A level, relative dosage reaction and stable-isotope dilution technique. At the same time, their dietary vitamin A intakes were estimated by weighted-food dietary survey. The dietary vitamin A requirement in young children was determined on the basis of dietary vitamin A intakes in Children with adequate vitamin A level.
Vitamin A supplementation (VAS) significantly reduces all-cause mortality when given after 6 months of age, but has a null or detrimental effect when given between 1-5 months. Studies of neonatal VAS (NNVAS) have produced conflicting findings. These age-pattern variations might result from immunological interactions between VAS and vaccines. The potential efficacy of NNVAS is being retested in 3 large new intervention trials with mortality as endpoint. Complementary mechanistic studies in animals and in human infants in The Gambia (this proposal) and Bangladesh have been commissioned to run in parallel. The investigators will use a 2-arm double blind RCT to test whether NNVAS modulates the early ontogeny of human immune development. Neonates, recruited through a peri-urban clinic in The Gambia, will receive either 50,000 International Units (IU) VAS orally within 48 hours of birth (intervention group, n=100) or a placebo (control group, n=100). Male and female neonates will be randomized separately at enrolment for later analyses by sex. All infants will be followed up from birth to age 1 year. A broad panel of immunological outcomes will examine whether NNVAS: a). normalises thymic development (thymic index by ultrasound); b). skews mycobacterial and recall antigen responses towards a Th2 profile; c). diminishes Th1 and Th17 reactivity to mycobacterial and recall antigens; d). diminishes the tuberculin skin test (TST) response; e). causes increased innate immune reactivity; f). increases the frequency of circulating regulatory T cells (Tregs) expressing gut homing receptors; g). enhances B cell immune responses after routine vaccination (increase of B cell numbers and activation status); h). increases circulating IgA in mucosal immune compartment, especially oral polio vaccine (OPV) specific IgA post-vaccination; i). decreases bacterial translocation, by improving mucosal barrier function; and j). decreases markers of infection or inflammation. Growth and morbidity will also be assessed.
The study will assess the relative bioavailability and bioefficacy of cryptoxanthin (CX) and beta-carotene (BC) from food sources for increasing breast milk carotenoid and retinol concentrations in lactating Bangladeshi women.
The purpose of this study is to determine the vitamin A equivalents in high-carotenoid varieties of cassava.
The project aims to evaluate the potential impact triple fortified rice grains, mixed into natural rice grains, can have on vitamin A status if fed to school children in Southern Thailand. Within a 60 day intervention study, changes in vitamin A status in young children fed the fortified rice compared to children consuming non-fortified rice will be assessed.