ongerich L

A comprehensive evaluation of food fortification with folic acid for the primary prevention of neural tube defects

BackgroundPericonceptional use of vitamin supplements containing folic acid reduces the risk of a neural tube defect (NTD). In November 1998, food fortification with folic acid was mandated in Canada, as a public health strategy to increase the folic acid intake of all women of childbearing age. We undertook a comprehensive population based study in Newfoundland to assess the benefits and possible adverse effects of this intervention.MethodsThis study was carried out in women aged 19–44 years and in seniors from November 1997 to March 1998, and from November 2000 to March 2001. The evaluation was comprised of four components: I) Determination of rates of NTDs; II) Dietary assessment; III) Blood analysis; IV) Assessment of knowledge and use of folic acid supplements.ResultsThe annual rates of NTDs in Newfoundland varied greatly between 1976 and 1997, with a mean rate of 3.40 per 1,000 births. There was no significant change in the average rates between 1991–93 and 1994–97 (relative risk [RR] 1.01, 95% confidence interval [CI] 0.76–1.34). The rates of NTDs fell by 78% (95% CI 65%–86%) after the implementation of folic acid fortification, from an average of 4.36 per 1,000 births during 1991–1997 to 0.96 per 1,000 births during 1998–2001 (RR 0.22, 95% CI 0.14–0.35). The average dietary intake of folic acid due to fortification was 70 μg/day in women aged 19–44 years and 74 μg/day in seniors. There were significant increases in serum and RBC folate levels for women and seniors after mandatory fortification. Among seniors, there were no significant changes in indices typical of vitamin B12 deficiencies, and no evidence of improved folate status masking haematological manifestations of vitamin B12 deficiency. The proportion of women aged 19–44 years taking a vitamin supplement containing folic acid increased from 17% to 28%.ConclusionsBased on these findings, mandatory food fortification in Canada should continue at the current levels. Public education regarding folic acid supplement use by women of childbearing age should also continue.

Interpretation of serum digoxin values in renal failure.

We have studied three circumstances that have been reported to make interpretation of the serum digoxin concentration difficult in patients with renal failure: increased biotransformation; endogenous digitalis‐like factors (DLF); and sudden, unexpected increases in serum digoxin values, even after the discontinuation of digoxin. Biotransformation, as estimated by the percent true digoxin in serum, was comparable in patients with renal failure who were dependent on dialysis and in control subjects (76% vs. 73%). Certain commercial immunoassays did not, or rarely, gave values for DLF of clinical significance (>0.2 ng/ml digoxin equivalents) in patients with a wide range of renal dysfunction who were not receiving digoxin. With a sensitive method, values for DLF did not exceed 0.23 ng/ml in 22 dialysis patients dependent on dialysis, but were significantly increased in comparison with values in control subjects. The case histories of two patients with renal failure, acute illness, and sudden unexpected marked increases in serum digoxin concentrations are presented and possible explanations are discussed.

Deuterium oxide prevents hypertension and elevated cytosolic calcium in hypertensive rats.

Increased calcium uptake in vascular tissue, leading to elevated cytosolic free calcium, has been implicated in the pathophysiology of hypertension. This study examined the dose-dependent effect of deuterium oxide (5%, 10%, or 20% in drinking water) on systolic blood pressure, aortic calcium uptake, and platelet cytosolic free calcium in spontaneously hypertensive rats. Starting at age 8 weeks, spontaneously hypertensive rats were divided into four groups of six animals each. The drinking water of groups 1, 2, 3, and 4 was replaced by 100% water and 5%, 10%, and 20% deuterium oxide in water, respectively, for another 7 weeks. Ten Wistar-Kyoto rats, age 8 weeks, were given 100% water for the next 7 weeks. The usual increase in systolic blood pressure and the associated increase in aortic calcium uptake and platelet cytosolic free calcium in spontaneously hypertensive rats at age 15 weeks was lowered in a dose-dependent manner by deuterium oxide. Deuterium oxide also prevented renal vascular changes in spontaneously hypertensive rats. A minimum dose of 10% deuterium oxide was needed to completely prevent the development of hypertension, elevated aortic calcium uptake, platelet cytosolic free calcium, and renal vascular changes in spontaneously hypertensive rats.

Assessment of specific gravity determined by Ames N-Multistix-SG

Specific gravity (SG) was determined in 204 urines by N-Multistix-SG solid phase test strip. Seventy-seven of the urines were from patients with known renal disease or were positive for protein or glucose, or had pH greater than 6.4 (Group I) and were assayed for osmolality, SG by urinometer and refractometer, and several other parameters, intercorrelations were calculated. Osmolality was used as the gold standard. In Group I, correlation of osmolality with N-Multistix SG (r = 0.66) was not significantly different (p greater than 0.1) from that found with SG determined by refractometer (r = 0.72), or urinometer (r = 0.60). The correlation coefficient for 45 N-Multistix-SG values determined by two staff members was 0.91. For the 127 Group II normal urines, the correlation coefficient between Multistix-SG and SG by refractometer was 0.85. Multistix-SG avoids the errors related to large molecules such as glucose and radiographic contrast media seen with SG determined by urinometer and refractometer (uncorrected for glucose) and was found to have comparable accuracy to these two methods when compared with osmolality, in patients with known renal disease or abnormal urinalysis.