Donald George Weir

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Using data from a recent case-control study, a woman's risk of having a child with a neural tube defect (NTD) was found to be associated with early pregnancy red cell folate levels in a continuous dose-response relationship. These findings were used to calculate the reduction in NTD cases that would be expected under two different strategies to raise folate(More)
Blood was taken at the first antenatal clinic from 56,049 pregnant women. Neural tube defect (NTD) pregnancies (81) were compared to controls (247) for plasma vitamin B12 (B12) (ng/l), plasma folate (microgram/l), and red cell folate (RCF) (microgram/l). Median values were significantly different and were, respectively, 243 and 296 (p = 0.001); 3.47 and(More)
Elevated plasma homocysteine, an independent risk factor for cardiovascular disease (CVD) can be lowered by administration of pharmacological doses of folic acid. The effect of lower doses in apparently normal subjects is currently unknown but is highly relevant to the question of food fortification. Healthy male volunteers (n = 30) participated in a(More)
It is now well-established that folic acid, taken peri-conceptionally, can reduce the risk of neural tube defects (NTDs). Recent work has demonstrated that an abnormality of homocysteine metabolism is a critical factor. The gene for 5,10 methylenetetrahydrofolate reductase, an enzyme important in homocysteine metabolism, was studied in relation to NTDs. To(More)
Recent reports have implicated the "thermolabile" (T) variant of methylenetetrahydrofolate reductase (MTHFR) in the causation of folate-dependent neural tube defects (NTDs). We report herein the largest genetic study of NTD cases (n=271) and families (n=218) to date, establishing that, in Ireland, the "TT" genotype is found in 18.8% of cases versus 8.3% of(More)
Periconceptual consumption of folic acid has been shown to decrease the incidence of neural tube defects. The strategy of universal fortification of staple foodstuffs with folic acid presents the possibility of life-long exposure to unmetabolized folic acid. Chief among the risks of exposure to folic acid in the circulation is that of masking the diagnosis(More)
BACKGROUND There is concern that the incidence of non-Hodgkin's lymphoma (NHL) will rise with increasing use of immunosuppressive therapy. AIMS Our aim was to determine the risk of NHL in a large cohort of patients with inflammatory bowel disease (IBD), and to study the association between IBD, NHL, and immunosuppressive therapy. METHODS We studied 782(More)
BACKGROUND The dietary reference values for folate, as for other nutrients, are targeted to the general and supposedly normal population, not people with special needs, such as those with genetic or metabolic abnormalities or diseases. However, 5-15% of general populations are homozygous for a thermolabile variant of 5,10-methylenetetrahydrofolate reductase(More)
BACKGROUND Current data suggest that physiologic doses of vitamin B-6 have no significant homocysteine-lowering effect. It is possible that an effect of vitamin B-6 was missed in previous trials because of a much greater effect of folic acid, vitamin B-12, or both. OBJECTIVE The aim of this study was to investigate the effect of low-dose vitamin B-6(More)
1. Conflicting reports exist as to the organ distribution of betaine-homocysteine methyltransferase (EC 2.1.1.5). It is important to establish its presence or absence in brain, since its substrate, betaine, has recently become established in the treatment of certain diseases involving this organ. 2. It remains unclear whether the reported success of this(More)