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At least 1,009 records · Page 56Linked to original sources
PubMed2003

Effect of long-term carbamazepine therapy on serum lipids, vitamin B12 and folic acid levels in children.

Serum triglycerides, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), vitamin B12 and folic acid levels were studied in 16 children with epilepsy who had been receiving carbamazepine (CBZ), and in 16 healthy children. Our purpose was to determine whether there was any effect of CBZ therapy on serum lipids, vitamin B12 and folic acid levels. Age ranged from 5 to 19 years (12.25 +/- 3.79 years) and 5.5 to 18 years (12.16 +/- 3.53 years) in the study and control groups, respectively. The duration of CBZ therapy in the patients was between 1 and 4.5 years (3.01 +/- 1.04 years). Serum CBZ level varied between 4 and 12 microg/ml (6.26 +/- 2.07 microg/ml). There was no statistically significant difference in serum triglycerides, TC, HDL-C, LDL-C, VLDL-C or vitamin B12. However, mean folic acid level was found to be lower in the study group than that of the control group (p < 0.05). Nonetheless, serum folic acid levels were within the normal range in all patients. Our study demonstrated that CBZ therapy does not affect serum lipids, vitamin B12 and folic acid levels, and may safely be used with regard to these parameters in children.

Adolescent↗
PubMed2006

Serum homocysteine, vitamin B 12 and folic acid levels in different types of glaucoma.

BACKGROUND: This study was performed to compare levels of serum homocysteine (Hcy), vitamin B12 and folic acid in patients with primary open-angle glaucoma (POAG), pseudoexfoliative glaucoma (PEXG), normotensive glaucoma (NTG) and healthy controls. METHODS: Twenty-five patients with POAG, 24 with PEXG, and 18 with NTG, along with 19 control healthy subjects were included this prospective study. Levels of serum Hcy were measured using immunoassay, and those of serum vitamin B12 and folic acid were measured using competitive chemiluminescent enzyme immunoassay. RESULTS: The mean Hcy concentration in the PEXG group was significantly higher (P < 0.001) as compared to the other groups. There were no significant differences with respect to the mean Hcy concentrations among other groups (P > 0.05). There were no statistical differences in serum vitamin B12 levels among POAG, PEXG, NTG and control subjects (P > 0.05). The mean serum folic acid level was significantly lower in the subjects with PEXG (P < 0.009). However, the mean folic acid concentrations among the other groups did not differ significantly (P > 0.05). CONCLUSION: Elevated levels of Hcy in PEXG may explain the role of endothelial dysfunction among patients with PEXG.

Aged↗
PubMed1962

Changes in serum vitamin B12 levels in patients with megaloblastic anaemia treated with folic acid.

In 21 patients with megaloblastic anaemia associated with the tropical malabsorption syndrome serum vitamin B(12) levels have been measured serially before and during parenteral folic acid therapy. In 11 patients there was a significant rise in serum B(12) levels, reaching a peak three to 17 days after starting the folic acid. In three of these cases, absorption of labelled B(12) was the same before and after the administration of folic acid. In two cases there was a fall in serum B(12) levels and in seven there was no change. In one case small amounts of folic acid produced no change in serum B(12) levels, whereas larger doses produced a prompt but transient rise.

Anemia↗
PubMed2000

Folic acid targeting of protein conjugates into ascites tumour cells from ovarian cancer patients.

Despite a wealth of in vitro data describing the use of folic acid for drug and DNA delivery into ovarian cancer cell lines, there have been no reports describing the targeting of such compounds to freshly isolated tumour cells. We have carried out a study to determine the usefulness of folic acid as a targeting ligand for ovarian cancer by measuring the uptake of folic acid-BSA-FITC in tumour cells isolated from the ascitic fluid of ovarian cancer patients. In 7 out of 7 patients we have found folic acid mediated uptake of the fluorescently labelled albumin, with the accumulation (average cell fluorescence) and differential uptake (ratio between receptor mediated and fluid phase uptake) varying between patients. Accumulation of folic acid-albumin FITC occurs in ascites tumour cells expressing the epithelial cell marker EMA, with a significant proportion of EMA negative cells also accumulating the conjugate. There is no correlation between cell cycle and uptake of folic acid-BSA-FITC. These results suggest that folic acid-targeting of therapeutics is a promising approach for the treatment of ovarian cancer.

Ascites↗
PubMed1999

Effects of oral folic acid supplementation on endothelial function in familial hypercholesterolemia. A randomized placebo-controlled trial.

BACKGROUND: Folates have been suggested to be of benefit in reducing cardiovascular risk. The present study was designed to examine whether oral folic acid supplementation could improve endothelial function as an intermediate end point for cardiovascular risk in patients with increased risk of atherosclerosis due to familial hypercholesterolemia (FH). METHODS AND RESULTS: In a prospective, randomized, double-blind, placebo-controlled study with crossover design, we evaluated the effects of 4 weeks of treatment with oral folic acid (5 mg PO) on endothelial function in FH. In 20 FH patients, forearm vascular function was assessed at baseline, after 4 weeks of folic acid treatment, and after 4 weeks of placebo treatment by venous occlusion plethysmography, with serotonin and sodium nitroprusside used as endothelium-dependent and -independent vasodilators. In addition, we examined the vasoconstrictor response to the NO synthase inhibitor N(G)-monomethyl-L-arginine to assess basal NO activity. In FH patients, folic acid supplementation restored the impaired endothelium-dependent vasodilation, whereas it did not significantly influence endothelium-independent vasodilation or basal forearm vasomotion. There was a trend toward improvement in basal NO activity. CONCLUSIONS: These data demonstrate that oral supplementation of folic acid can improve endothelial function in patients with increased risk of atherosclerotic disease due to hypercholesterolemia, without changes in plasma lipids.

Administration, Oral↗
PubMed1996

Folic acid fortification of the food supply. Potential benefits and risks for the elderly population.

OBJECTIVE: To estimate the potential benefits and risks of food folic acid fortification for an elderly population. Benefits are expected through the improvement of folate and homocysteine status, but there is also a risk of masking or precipitating clinical manifestations related to vitamin B12 deficiency with increasing exposure to folic acid. DESIGN: Cross-sectional analysis, with projected change at various levels of folic acid fortification. SETTING: Participants in the Framingham Heart Study original cohort. PARTICIPANTS: A total of 747 subjects aged 67 to 96 years who both completed usable food frequency questionnaires and had blood concentrations of B vitamins and homocysteine measured. MAIN OUTCOME MEASURES: Projected blood folate and homocysteine concentrations and combined high folate intake and low plasma vitamin B12 concentration. RESULTS: Percentages of this elderly population with folate intake below 400 microg/d are projected to drop from 66% at baseline to 49% with 140 microg of folate per 100 g of cereal-grain product, to 32% with 280 microg, to 26% with 350 microg, and to 11% with 700 microg. Percentages with elevated homocysteine concentrations (>14 micromol/L) are projected to drop from 26% at baseline to 21% with 140 microg of folate per 100 g, to 17% with 280 microg, to 16% with 350 microg, and to 12% with 700 microg. Without fortification, the prevalence of combined high folate intake (>1000 microg/d) and low plasma vitamin B12 concentration (<185 pmol/L [<250 pg/mL]) was 0.1%. This is projected to increase to 0.4% with folate fortification levels of 140 to 350 microg/100 g and to 3.4% with 700 microg. CONCLUSION: The evidence suggests that, at the level of 140 microg/100 g of cereal-grain product mandated by the Food and Drug Administration, the benefits of folate fortification, through projected decreases in homocysteine level and heart disease risk, greatly outweigh the expected risks. However, quantification of the actual risks associated with vitamin B12 deficiency remains elusive. Before higher levels of folic acid fortification are implemented, further research is needed to better understand the clinical course of various forms of vitamin B12 deficiency, to measure the potential effect of high folate intake on this course, and to identify cost-effective approaches to the identification and treatment of all forms of vitamin B12 deficiency.

Aged↗
PubMed2001

Knowledge and use of folic acid among women of reproductive age--Michigan, 1998.

Neural tube defects (NTDs), which include spina bifida and anencephaly, are serious malformations that occur in the developing fetus during the first 17-30 days after conception. Consumption of supplements containing folic acid can reduce NTDs 50%-70%. In the United States, approximately 4000 pregnancies are affected by NTDs each year, including approximately 140 infants in Michigan. In 1992, the U.S. Public Health Service recommended that all women of childbearing age consume at least 400 microg of folic acid daily. In 1998, the Institute of Medicine reaffirmed that recommendation and added that women capable of becoming pregnant take 400 microg of synthetic folic acid daily from fortified foods and/or supplements and consume a balanced, healthy diet of folate-rich foods. This report summarizes findings from the 1998 Behavioral Risk Factor Surveillance System (BRFSS) about multivitamin use and folic acid knowledge among women of reproductive age in Michigan. The findings suggest that public health campaigns that promote the consumption of folic acid should target women who are young, unmarried, obese, smoke, eat few fruits and vegetables, and have a low level of education.

Adult↗
PubMed1996

Case-control study of periconceptional folic acid supplementation and oral clefts.

There is consistent evidence that the risk of neural tube defects is decreased by periconceptional supplementation with folic acid. A similar protective effect has been postulated for oral clefts. A case-control study was conducted in greater metropolitan Boston; Massachusetts; Philadelphia, Pennsylvania; and southeastern Ontario, Canada, from 1988 through 1991 to test the hypothesis that folic acid supplementation during the periconceptional period reduces the risk of oral clefts. Crude and multivariate-adjusted relative risks were calculated for all oral clefts (n = 303), cleft palate (n = 108), and cleft lip with or without cleft palate (n = 195). Controls (n = 1,167) were liveborn or stillborn infants less than age 6 months who had various congenital anomalies other than oral clefts, neural tube defects, or other "midline defects." Adjusted relative risks and 95 percent confidence intervals for daily folic acid supplementation during the periconceptional period were: oral clefts, 1.1 (95% confidence interval (CI) 0.8-1.7), cleft palate, 0.9 (95% CI 0.5-1.6), and cleft lip with or without cleft palate, 1.3 (95% CI 0.8-2.1). These findings do not support a protective association between the periconceptional use of folic acid supplements and the risk of oral clefts.

Case-Control Studies↗
PubMed2005

Rates of selected birth defects in relation to folic acid fortification, Hawaii, 1986-2002.

Because of studies suggesting that folic acid use reduces risk of various birth defects, the Unites States fortified enriched cereal grains with folic acid in 1998. To determine whether this fortification reduced rates for birth defects in Hawaii, rates were calculated before and after fortification. Of the 19 birth defects categories studied, the rates for 16 were lower after fortification.

Congenital Abnormalities↗
PubMed2005

[Folate and folic acid intake estimation and food enrichment requirements].

The term "folate" is a generic way to name the different forms derived from folic acid, one of the B vitamins (specifically B9 vitamin). They are essential in the metabolism when they act as cofactors in the transfer reactions of one carbon. However, only plants and microorganisms are able to synthesize them de novo, in such a way that both animals and human beings have to intake them through their diet. Folic acid is widely spread in nature, mainly in vegetables, liver ans cereals. However, nowadays, the lack of folates in the diet is one of the most common nutritional deficiencies in the world, and it has serious consequences on human health. There is evidence that even in developed countries folate intake is usually low; and even, is some cases, below optima levels. The authorities in several countries have adapted different norms related to folic acid, fortifying staple food such as dairy products or cereals, mandatory (U.S.A., Canada or Chile) or voluntary (most of the European countries).

Adolescent↗
PubMed2006

Hyperhomocysteinemia induces liver injury in rat: Protective effect of folic acid supplementation.

Hyperhomocysteinemia, a condition of elevated blood homocysteine level, is an independent risk factor for cardiovascular diseases. Hyperhomocysteinemia is also found in patients with liver diseases. However, the direct effect of homocysteine on liver injury is not well known. Folic acid supplementation is a promising approach for improving endothelial function in patients with hyperhomocysteinemia. The aim of this study was to investigate the direct effect of hyperhomocysteinemia on liver injury and whether folic acid could offer any protective effect to the liver. Hyperhomocysteinemia was induced in rats fed a high-methionine diet for 4 weeks. There was a significant increase in the serum aspartate aminotransferase and alanine aminotransferase activities reflecting liver injury in hyperhomocysteinemic rats. Hepatic NAD(P)H oxidase was activated during hyperhomocysteinemia leading to increased superoxide anion production and peroxynitrite formation in the liver. As a consequence, the level of lipid peroxides was significantly elevated in livers of hyperhomocysteinemic rats. Folic acid supplementation effectively inhibited NAD(P)H oxidase-mediated superoxide anion production leading to reduced lipid peroxidation in the liver. Folic acid supplementation also alleviated hyperhomocysteinemia-induced liver injury. These results suggest that hyperhomocysteinemia can cause liver injury and supplementation of folic acid offers a hepatoprotective effect.

Animals↗
PubMed2001

Determination of serum B12 vitamin and folic acid levels in patient with stroke.

The aim of this study is to evaluate whether any relationship between stroke and vitamin B12, folic acid concentration. We examined 50 patients with stroke (male: 26 and female: 24) aged between (mean +/- SD, year) 59 +/- 14 and 16 control subjects (male: 6 and female: 10) aged between (mean +/- SD, year) 53 +/- 11. Patients were classified into two groups as infarct and hemorrhagic by using Computerised Brain Tomography and Cranial Nuclear Magnetic Resonance Imaging techniques. The percentage of patients with infract was 47.5% in female and 52.5% in male while it was 40% in female and 60% in male with hemorrhagic. The vitamin B12 levels of patients with infarct, hemorrhagic and control group were found as mean +/- SEM, 355 +/- 47 pg/ml, 313 +/- 58 pg/ml, 1569 +/- 258 pg/ml and folic acid levels 13.4 +/- 2.6 ng/ml, 7.7 +/- 1.0 ng/ml, 14.8 +/- 4.0 ng/ml, respectively. The significant difference was found between subgroups of patients with stroke and control group in both folic acid and B12 vitamin levels (p < 0.001 and p < 0.0001, respectively). But, there was no significant difference between vitamin B12 and folic acid levels of patients with hemorrhagic and infarct. In order to well understand the effects of these vitamin in patients with stroke, more detailed follow up studies with long period are needed.

Cerebral Hemorrhage↗
PubMed1980

Effect of folic acid supplementation on pregnancy in the squirrel monkey (Saimiri sciureus).

Supplementation of squirrel monkeys with folic acid improved hematologic and folate status, maternal weight gain during pregnancy, and infant birth weight. Thus the folate content in the stock diet (1.4 microgram/g) did not meet the requirement for pregnancy. Low plasma vitamin B12 values suggest that vitamin B12 in the stock diet (22 ng/g) also was not adequate. Changes with folic acid supplementation are similar to those for human subjects, indicating that the squirrel monkey is an appropriate model for folic acid deficiency in pregnancy in man.

Animals↗
PubMed2006

Hospitalizations of newborns with folate-sensitive birth defects before and after fortification of foods with folic acid.

CONTEXT: The prevalence of neural tube defects is reduced in populations of women who receive folic acid supplementation. Since 1998, grain products in the United States have been fortified with folic acid. Fortification may have additional benefits by reducing the national prevalence of newborn hospitalizations for other folate-sensitive birth defects. OBJECTIVE: Our purpose with this work was to compare rates of hospitalizations of newborns with folate-sensitive birth defects before and after implementation of fortification of grains. METHOD: National hospital discharge data from the Healthcare Cost and Utilization Project were used to compute rates of newborn hospitalizations for selected birth defects per 10,000 live births in the United States. Newborn hospitalization rates involving congenital anomalies recognizable at birth were analyzed for 5 years before fortification of grains and 5 years after fortification. Additional analyses compared changes in newborn hospitalization rates for birth defects by race/ethnicity, income, insurance status, and region of the country. RESULTS: Newborn hospitalization rates for spina bifida decreased 21% from 1993-1997 to 1998-2002. Newborn hospitalization rates also decreased for anencephaly (20%) and limb-reduction defects (4%). Decline in hospitalizations for spina bifida occurred more often among Hispanic newborns (33%) than among white (13%) or black (21%) newborns. Decline in limb-reduction defects was seen primarily among blacks (11%). Findings using hospitalization data were similar to recent reports using birth defect surveillance systems with the exception of findings for orofacial clefts and conotruncal heart defects. No reductions were noted in newborn hospitalizations for these anomalies. CONCLUSIONS: Results from this ecological study fail to demonstrate substantial declines in newborn hospitalizations beyond those anticipated from a reduction in neural tube defects. The society-wide impact of the fortification program on birth defects and other health conditions should continue to be monitored.

Congenital Abnormalities↗
PubMed1999

Knowledge and use of folic acid by women of childbearing age--United States, 1995 and 1998.

In the United States, approximately 4000 pregnancies are affected by neural tube defects each year; 50%-70% of these developmental defects could be prevented with daily intake of 400 microg of the B vitamin folic acid throughout the periconceptional period. In 1992, the Public Health Service recommended that all women capable of becoming pregnant consume 400 microg of folic acid daily throughout their childbearing years to reduce their risk for having a pregnancy affected by neural tube defects. In 1998, the Institute of Medicine recommended that all women of childbearing potential consume 400 microg of synthetic folic acid per day from fortified foods and/or a supplement in addition to food folate from a varied diet. This report summarizes the findings of a survey conducted during July-August 1998 to assess folic acid knowledge and practices among women of childbearing age in the United States and compares these results with those from a similar survey conducted in 1995. The findings indicate that 7% of women know folic acid should be taken before pregnancy to reduce the risk for neural tube defects.

Adolescent↗
PubMed2006

Unmetabolized folic acid in plasma is associated with reduced natural killer cell cytotoxicity among postmenopausal women.

Folic acid (FA) supplements and food fortification are used to prevent neural tube defects and to lower plasma homocysteine. Through exposure to food fortification and vitamin supplement use, large populations in the United States and elsewhere have an unprecedented high FA intake. We evaluated dietary and supplemental intakes of folate and FA in relation to an index of immune function, natural killer cell (NK) cytotoxicity, among 105 healthy, postmenopausal women. Among women with a diet low in folate (<233 microg/d), those who used FA-containing supplements had significantly greater NK cytotoxicity (P = 0.01). However, those who consumed a folate-rich diet and in addition used FA supplements > 400 microg/d had reduced NK cytotoxicity compared with those consuming a low-folate diet and no supplements (P = 0.02). Prompted by this observation, we assessed the presence of unmetabolized FA in plasma as a biochemical marker of excess FA. Unmetabolized folic acid was detected in 78% of plasma samples from fasting participants. We found an inverse relation between the presence of unmetabolized FA in plasma and NK cytotoxicity. NK cytotoxicity was approximately 23% lower among women with detectable folic acid (P = 0.04). This inverse relation was stronger among women >or= 60 y old and more pronounced with increasing unmetabolized FA concentrations (P-trend = 0.002). Because of the increased intake of FA in many countries, our findings highlight the need for further studies on the effect of long-term high FA intake on immune function and health.

Diet↗
PubMed1964

THE ASSAY OF FOLIC-ACID ACTIVITY OF LIVER.

Methods of preparing liver for the microbiological assay of folic-acid activity have been compared. Maximum values were obtained by incubating an alkaline homogenate of liver in the presence of ascorbic acid for five hours at 37 degrees C. Most other procedures resulted in significant loss of folic-acid activity.

Ascorbic Acid↗