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Chan, Y. M.

Publications and source records attributed to Chan, Y. M..

3 recordsLinked to original sources

Vitamin D deficiency during pregnancy and its associated factors among third trimester Malaysian pregnant women

BackgroundDespite perennial sunshine, vitamin D deficiency is prevalent among Malaysian especially pregnant women.\n\nObjectiveTo determine the vitamin D status and its associated factors among third trimester pregnant women attending government health clinics in Selangor and Kuala Lumpur, Malaysia.\n\nMethodsInformation on socio-demographic characteristics, obstetrical history, vitamin D intake, supplement use, and sun exposure were obtained through face-to-face interviews. Serum 25-hydroxyvitamin D concentration was measured and classified as deficient (< 30 nmol/L), insufficient (30-50 nmol/L), and sufficient ([&ge;] 50 nmol/L).\n\nResultsOf the 535 pregnant women recruited, 42.6% were vitamin D deficient. They consumed an average of 8.7 {+/-} 6.7 g of vitamin D daily. A total of 80.4% of the vitamin D were obtained from the food sources, while 19.6% were from dietary supplements. Fish and fish products showed the highest contribution to vitamin D intake (35.8%). The multivariate generalized linear mixed models, with clinic as a random effect, indicates that higher intake of vitamin D is associated with lower risk of vitamin D deficiency among pregnant women (OR = 0.96; 95% CI = 0.93-0.99). Non-Malay pregnant women had lower odds of having vitamin D deficiency (OR = 0.13; 95% CI = 0.04-0.37) compared to Malays. No associations were found between age, educational level, monthly household income, work status, gravidity, parity, pre-pregnancy body mass index, total hours of sun exposure, total percentage of body surface area, and sun exposure index per day with vitamin D deficiency.\n\nConclusionsVitamin D deficiency is prevalent among Malaysian pregnant women. Considering the possible adverse obstetric and fetal outcomes of vitamin D deficiency during pregnancy, antenatal screening of vitamin D levels and nutrition education should be emphasised by taking into consideration ethnic differences.

epidemiology↗

Relating excitatory and inhibitory neurochemicals to visual perception: a magnetic resonance study of occipital cortex between migraine events.

Certain perceptual measures have been proposed as indirect assays of brain neurochemical status in people with migraine. One such measure is binocular rivalry, however, previous studies have not measured rivalry characteristics and brain neurochemistry together in people with migraine. This study compared spectroscopy-measured levels of GABA and Glx (glutamine and glutamate complex) in visual cortex between 16 people with migraine and 16 non-headache controls, and assessed whether the concentration of these neurochemicals explains, at least partially, inter-individual variability in binocular rivalry perceptual measures. Mean Glx level was significantly reduced in migraineurs relative to controls, whereas mean occipital GABA levels were similar between groups. Neither GABA levels, nor Glx levels correlated with rivalry percept duration. Our results thus suggest that the previously suggested relationship between rivalry percept duration and GABAergic inhibitory neurotransmitter concentration in visual cortex is not strong enough to enable rivalry percept duration to be reliably assumed to be a surrogate for GABA concentration, at least in the context of healthy individuals and those that experience migraine.

neuroscience↗

The RNA-binding site of poliovirus 3C protein doubles as a phosphoinositide-binding domain

Some viruses use phosphatidylinositol phosphate (PIP) to mark membranes used for genome replication or virion assembly. PIP-binding motifs of cellular proteins do not exist in viral proteins. Molecular-docking simulations revealed a putative site of PIP binding to poliovirus (PV) 3C protein that was validated using NMR spectroscopy. The PIP-binding site was located on a highly dynamic -helix that also functions in RNA binding. Broad PIP-binding activity was observed in solution using a fluorescence polarization assay or in the context of a lipid bilayer using an on-chip, fluorescence assay. All-atom molecular dynamics simulations of the 3C protein-membrane interface revealed PIP clustering and perhaps PIP-dependent conformations. PIP clustering was mediated by interaction with residues that interact with the RNA phosphodiester backbone. We conclude that 3C binding to membranes will be determined by PIP abundance. We suggest that the duality of function observed for 3C may extend to RNA-binding proteins of other viruses.

biochemistry↗