Subclinical vitamin B12 deficiency in pregnant women attending an antenatal clinic in Nigeria.

SUMMARY: Inadequate vitamin B12 status in a pregnant woman increases the risk for adverse maternal and fetal outcomes. The use of serum vitamin B12 concentration alone to assess vitamin B12 status in pregnant women is unreliable because of the decrease in serum vitamin B12 levels in normal pregnancy. The combination of serum vitamin B12 and methylmalonic acid (MMA) concentrations may provide a better estimate of vitamin B12 status. We obtained blood samples from 98 pregnant women in the third trimester at an antenatal clinic in Jos, Nigeria. All subjects were taking iron and folate supplements. Twelve of the subjects had a serum vitamin B12 concentration <148 pmol/l and 18 subjects had a serum MMA level >271 nmol/l. Using a combination of low serum vitamin B12 and elevated MMA concentrations, eight subjects were classified as having subclinical vitamin B12 deficiency. Because of the potential harmful consequences of vitamin B12 deficiency in pregnant women, it would be advisable to add vitamin B12 supplements to the existing regimen of folate and iron supplements currently provided to pregnant women in Nigeria.

Lysosomal enzymes in preeclamptic women in northern Nigeria.

BACKGROUND: The incidence of preeclampsia is high in northern Nigeria, as it is in many other developing countries, and preeclampsia is associated with significant maternal and fetal morbidity and mortality. We inquired if proteinuria or hypertension alone could account for the altered concentrations of urinary lysosomal hydrolases that have been reported in preeclamptic women and pregnant women without preeclampsia. METHODS: The activities of urinary beta-hexosaminidase and beta-galactosidase were determined fluorometrically in pregnant women assigned to one of four groups: Group I: 41 preeclamptic women; Group II: 31 hypertensive aproteinuric women; Group III: 44 normotensive proteinuric women; and Group IV: 52 healthy pregnant women (controls). RESULTS: The urinary beta-hexosaminidase concentrations were decreased in the preeclamptic women (P<0.005) and proteinuric women (P<0.001) when compared to the healthy pregnant controls. There was no significant difference in beta-hexosaminidase concentrations between the hypertensive women and the healthy pregnant controls. The urinary beta-galactosidase concentrations for preeclamptic, hypertensive, and proteinuric women did not differ significantly versus healthy pregnant controls. CONCLUSIONS: The reduced urinary excretion of beta-hexosaminidase in preeclamptic women is associated with proteinuria, but not hypertension. Measuring urinary concentrations of lysosomal hydrolases alone or in conjunction with urinary protein concentrations is not likely to be useful in predicting or monitoring the clinical course of preeclampsia; however, it might prove important in gaining a more complete understanding of the pathogenesis of renal tubular epithelial cell injury and proteinuria that occurs in preeclampsia.

Effects of digoxinlike immunoreactive substances and digoxin FAB antibodies on the new digoxin microparticle enzyme immunoassay.

Digoxin-like immunoreactive substance (DLIS) is known to interfere with fluorescence polarization immunoassay (FPIA) (Digoxin II, Abbott Laboratories) and falsely elevates the total digoxin concentrations. Digoxin FAB antibody (Digibind) is also known to affect digoxin results by FPIA assay. The authors studied the effects of DLIS and Digibind on a new microparticle enzyme immunoassay (MEIA) for digoxin recently introduced by Abbott Laboratories, compared with the standard FPIA method and chemiluminescence assay (ACS-digoxin, Ciba-Corning). They studied 30 volume-expanded patients (term pregnancy, liver and renal disease) for the presence of DLIS. None of these patients received digoxin. They observed measurable DLIS concentrations in 12 of 30 patients by the FPIA assay and in only 1 patient by both MEIA and ACS assays. The concentration of DLIS in that patient was 0.31 ng/ml of digoxin equivalent by the MEIA assay, 0.36 ng/ml by the ACS assay, and 1.15 ng/ml by the FPIA assay. When they supplemented serum containing digoxin with low to high concentrations of digibind (0.5, 1.0, 2.0 and 4.0, 10, and 20 micrograms/ml), and measured digoxin concentrations by FPIA, MEIA, and ACS assays, they observed lower than expected values of total digoxin. However, when they supplemented serum containing no digoxin with high concentration of digibind (5.0, 10.0 and 20.0 micrograms/ml) and supplemented protein-free ultrafiltrates with digoxin, they observed expected digoxin concentrations in the ultrafiltrates by all three assays, indicating that the ultrafiltrates are essentially free of digibind.

Elevated free fatty acid concentrations in lipemic sera reduce protein binding of valproic acid significantly more than phenytoin.

Higher concentrations of free valproic acid and phenytoin have been reported in patients with uremia and liver disease. Free fatty acids also displace valproic acid and phenytoin. This is a study of the magnitude of displacement of valproic acid and phenytoin from protein binding by free fatty acid in lipemic sera. Higher concentrations of free fatty acids in lipemic sera affected protein binding of valproic acid significantly more than that of phenytoin. Supplementing normal sera with free fatty acids also increased the free concentrations of both valproic acid and phenytoin as expected, but the observed effect was several times higher in magnitude with valproic acid. There was an increased free fraction of valproic acid in patients who received valproic acid and had hypertriglyceridemia. In a patient with uremia, there was also a significant increase in free valproic acid concentration after routine hemodialysis caused by an increase in free fatty acid concentration secondary to hemodialysis. Increased protein binding of valproic acid in sera was observed after treatment with activated charcoal because charcoal can remove free fatty acid. Because higher free fatty acid concentration significantly affects protein binding of valproic acid, careful monitoring of free valproic acid in patients with lipid disorder may be beneficial.