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PubMed1964

FOLIC ACID METABOLISM IN ANTIFOLIC-RESISTANT MUTANTS OF STREPTOCOCCUS FAECALIS.

Johnson, Alva H. (Sloan-Kettering Institute for Cancer Research, Rye, N.Y.), and Dorris J. Hutchison. Folic acid metabolism in antifolic-resistant mutants of Streptococcus faecalis. J. Bacteriol. 87:786-791. 1964.-Streptococcus faecalis ATCC 8043 and three of its mutants resistant to amethopterin were compared for their quantitative requirements for serine, purines, and thymine; for their quantitative requirements of folic acid (FA) for the synthesis de novo of serine, purines, and thymine; for the susceptibility to amethopterin of each pathway; and for the relative capacity of resting cells of each culture to synthesize N(5)-formyltetrahydrofolate (5-CHOFAH(4)) from FA and serine or FA and formate. The mutants were found to be both qualitatively and quantitatively different from one another and from the wild strain. The growth conditions, specifically the composition of the medium in which each mutant strain was selected, had a marked effect on the metabolic capacities of the mutants. The ability to synthesize serine, purines, and thymine, as observed from the FA requirements, directly reflected the level of resistance of each pathway to amethopterin. The resistant mutants were more efficient than the wild strain in the formation of 5-CHOFAH(4) from FA and formate and, furthermore, this formate activation paralleled their capacities in the synthesis de novo of serine. Alterations in purine and thymine biosyntheses were also observed.

Adenine↗
PubMed2006

Rationale and design of the Folic Acid for Vascular Outcome Reduction In Transplantation (FAVORIT) trial.

BACKGROUND: Patients with chronic kidney disease, including kidney transplant recipients, are at high risk for cardiovascular disease (CVD). In addition to the constellation of traditional CVD risk factors in chronic kidney disease, elevated total homocysteine (tHcy) is notably more prevalent among the general population. The Folic Acid for Vascular Outcome Reduction In Transplantation (FAVORIT) trial is designed to evaluate whether lowering tHcy using vitamin supplementation reduces CVD events in renal transplant recipients. METHODS: FAVORIT is a multicenter double-blind randomized controlled clinical trial. Participants are clinically stable renal transplant recipients who are 6 months or longer posttransplant with elevated tHcy. Patients are randomized to a multivitamin that includes either a high-dose or low-dose of folic acid (5 or 0 mg), vitamin B6 (50 or 1.4 mg), and vitamin B12 (1000 or 2 microg). The primary end point is a composite of incident or recurrent CVD outcomes, that is, coronary heart, cerebrovascular, or abdominal aortic/lower extremity arterial events. A sample size of 4000 is estimated to provide 87% power to detect a 20% treatment effect. Recruitment is expected to continue until July 2006, with follow-up through June 2010. RESULTS: From August 2002 through December 2004, 2234 of the target 4000 patients were enrolled. In accordance with trial design, mean (SD) screening tHcy was elevated (17.4 +/- 6.2 micromol/L), and mean (SD) estimated creatinine clearance was consistent with stable renal function (58.0 +/- 18.6 mL/min). Evaluating baseline results to date, 42% of the randomized participants had a history of diabetes mellitus, and 21% had prevalent CVD. CONCLUSIONS: The FAVORIT trial is designed with sufficient power and follow-up time to detect a clinically relevant change in CVD risk between renal transplant recipients receiving a high or low tHcy-lowering folic acid multivitamin. Preliminary screening and baseline data support the trial's objectives.

Adult↗
PubMed1962

Effects of folic acid on the phenylalanine tolerance test in phenylketonuria.

Phenylalanine tolerance tests were performed on four untreated children with phenylketonuria, aged 8 to 12 years, before and after 14 days of folic acid administration (70 mg./day). No significant changes were noted in the phenylalanine tolerance tests or in the general condition of the patients. This study was carried out because of recent findings that a folic acid derivative is a co-factor in the conversion of phenylalanine to tyrosine.

Antimetabolites↗
PubMed1976

A prophylactic trial of iron and folic acid supplements in pregnant Burmese women.

Hemoglobin (Hb) concentration, serum iron level, iron binding capacity and blood folate (Lactobacillus casei) activity were determined in 310 unselected pregnant Burmese women. Hb concentration was less than 11 g/dl in 72% of the women; the serum iron level was less than 50 mug/dl in 33%; serum folate activity was less than 3ng/ml in 13%; and red cell folate activity was less than 100 ng/ml in 17% of the women. Ninety-six of the women in our study were randomly divided into four groups, treated from the 22nd to the 25th week of pregnancy until full term with either ferrous sulfate containing 60 mg elemental iron twice daily, 5 mg folic acid twice daily, a combination of both, or a placebo only. At full term, Hb concentration fell in the groups given placebo or folic acid. On the other hand, in the groups given iron alone or iron plus folic acid there was an increase in Hb of 0.4 and 0.7 g/dl, respectively (intergroup difference not statistically significant). Serum iron and blood folate levels fell in the groups not receiving the appropriate hematinic. In spite of deficient serum and red cell folate levels in 30 and 40%, respectively, of the group on iron alone, the mean Hb concentration increased at full term and none of the women had a Hb concentration lower than 10 g/dl. Blood folate levels were lower in the iron-supplemented group than in the placebo group, indicating that iron deficiency does not aggravate the folate nutritional status.

Adolescent↗
PubMed2006

Folic acid: a public-health challenge.

Despite worldwide public-health campaigns recommending periconceptional daily supplementation of synthetic folic acid to reduce the risk of neural tube defects, many women are not following these recommendations. At the same time, in most European countries no decline in defects has been recorded in recent years. Vulnerable groups are those with a low standard of education, young people, and women with unplanned pregnancies. Furthermore, in most countries without mandatory fortification, the general population is not consuming the recommended 0.4 mg of food folate per day. Voluntary fortification improves the situation, but does not reach all parts of the population. In the USA, Canada, and Chile, mandatory fortification of flour substantially improved folate and homocysteine status, and neural tube defects rates fell by between 31% and 78%. Nevertheless, many countries do not choose mandatory folic acid fortification, in part because expected additional health benefits are not yet scientifically proven in clinical trials, in part because of feared health risks, and because of the issue of freedom of choice. Thus, additional creative public-health approaches need to be developed to prevent neural tube defects and improve the folate status of the general population.

Adult↗
PubMed2006

Population-level changes in folate intake by age, gender, and race/ethnicity after folic acid fortification.

OBJECTIVES: We sought to quantify the impact of the 1998 US Food and Drug Administration (FDA) folic acid fortification policy by estimating folate intake at the population level. METHODS: We analyzed total folate intake levels (from food and supplements) according to gender, age, and race/ethnicity, using data from 2 National Health and Nutrition Examination Surveys. We measured pre- and postfortification folate intake distributions, adjusted for measurement error, and examined proportions of the population who reached certain thresholds of daily total folate intake. RESULTS: Mean daily food and total folate intake increased by approximately 100 microg/day after fortification. The proportion of women aged 15-44 years who consume more than 400 microg/day of folate has increased since fortification, but has not yet reached the FDA's 50% target and varies by race/ethnicity from 23% to 33%. Among persons aged 65 years and older who may be at risk for masking a vita-microg/day (the min B12 deficiency, the percentage who consume more than 1000 "tolerable upper intake level") has at least doubled among Whites and Black men, but has remained less than 5% for all groups. CONCLUSIONS: Since fortification, folic acid intake among the US population has increased, and there are substantial variations by age, gender, and race/ethnicity.

Adolescent↗
PubMed2005

A diabetes-like environment increases malformation rate and diminishes prostaglandin E(2) in rat embryos: reversal by administration of vitamin E and folic acid.

BACKGROUND: Offspring of women with diabetes are at increased risk for congenital malformations and disturbed growth compared with infants from nondiabetic pregnancies. The precise biological process behind these effects is not yet completely clarified. Previous studies have suggested that diabetic embryopathy is associated with increased level of oxidative stress and disturbed arachidonic acid metabolism. The aim of the present study was to investigate whether a diabetes-like environment both in vivo and in vitro increases embryonic levels of isoprostanes and alters embryonic prostaglandin E(2) (PGE(2)) concentration. Furthermore, we studied whether vitamin E and folic acid treatment rectify such alterations. METHODS: Embryos from diabetic and nondiabetic rats at gestational days (GDs) 10 and 11 were used. In the in vitro experiments, we used whole embryo culture, which mimics pregnancy. GD 9 embryos from nondiabetic rats were cultured for either 24 hr (corresponding to GD 10) or 48 hr (corresponding to GD 11) and exposed to 10 or 30 mM glucose concentration with or without folic acid. RESULTS: Embryos from diabetic rats and embryos cultured in a high glucose concentration showed increased malformation rates. Dietary treatment with vitamin E in vivo and supplementation of folic acid in the culture medium with 30 mM glucose in vitro decreased the malformation rate, decreased embryonic isoprostane levels, and increased PGE(2) concentration. CONCLUSIONS: Diabetes-induced oxidative stress and disturbance of PGE(2) production may contribute to the embryonic dysmorphogenesis in the offspring of diabetic rodents and, thereby, may also have a role in human diabetic embryopathy.

Animals↗
PubMed2006

Trends of selected malformations in relation to folic acid recommendations and fortification: an international assessment.

BACKGROUND: Two crucial issues relative to the benefits and impact of folic acid in the prevention of birth defects are whether supplementation recommendations alone, without fortification, are effective in reducing the population-wide rates of neural tube defects (NTDs), and whether such policies can reduce the occurrence of other birth defects. Using data from 15 registries, we assessed rates and trends of 14 major defects, including NTDs, in areas with official recommendations or fortification to assess the effectiveness of recommendations and fortification on a wide range of major birth defects. METHODS: We evaluated surveillance data through 2003 on major birth defects from population-based registries from Europe, North America, and Australia. All included ascertainment of pregnancy terminations (where legal). Trends before and after policies or fortification were assessed via Poisson regression and were compared via rate ratios. RESULTS: Significant changes in trends were seen for NTDs in areas with fortification but not in areas with supplementation recommendations alone. For other major birth defects, there was an overall lack of major trend changes after recommendations or fortification. However, some significant declines were observed for select birth defects in individual areas. CONCLUSIONS: Recommendations alone remain an ineffective approach in translating the known protective effect of folic acid in population-wide decline in NTD rates. Fortification appears to be effective in reducing NTDs. The effect on other birth defects remains unclear.

Dietary Supplements↗
PubMedDate not supplied

The use of HPLC method for determination of the folic acid in multi-component vitamin preparations.

In the present study we tried to use HPLC method to determine the folic acid content in multivitamin and multimineral pharmaceutical preparations. The reverse phases technique was applied and measurements were made at the wavelength 282 nm. The elaborated method, because of its sufficient precision, accuracy as well as short time retention of folic acid may be used as an alternative method to microbiological.

Calibration↗
PubMed1999

Folic acid stimulation of the Galpha4 G protein-mediated signal transduction pathway inhibits anterior prestalk cell development in Dictyostelium.

In Dictyostelium discoideum, several G proteins are known to mediate the transduction of signals that direct chemotactic movement and regulate developmental morphogenesis. The G protein alpha subunit encoded by the Galpha4 gene has been previously shown to be required for chemotactic responses to folic acid, proper developmental morphogenesis, and spore production. In this study, cells overexpressing the wild type Galpha4 gene, due to high copy gene dosage (Galpha4HC), were found to be defective in the ability to form the anterior prestalk cell region, express prespore- and prestalk-cell specific genes, and undergo spore formation. In chimeric organisms, Galpha4HC prespore cell-specific gene expression and spore production were rescued by the presence of wild-type cells, indicating that prespore cell development in Galpha4HC cells is limited by the absence of an intercellular signal. Transplanted wild-type tips were sufficient to rescue Galpha4HC prespore cell development, suggesting that the rescuing signal originates from the anterior prestalk cells. However, the deficiencies in prestalk-specific gene expression were not rescued in the chimeric organisms. Furthermore, Galpha4HC cells were localized to the prespore region of these chimeric organisms and completely excluded from the anterior prestalk region, suggesting that the Galpha4 subunit functions cell-autonomously to prevent anterior prestalk cell development. The presence of exogenous folic acid during vegetative growth and development delayed anterior prestalk cell development in wild-type but not galpha4 null mutant aggregates, indicating that folic acid can inhibit cell-type-specific differentiation by stimulation of the Galpha4-mediated signal transduction pathway. The results of this study suggest that Galpha4-mediated signals can regulate cell-type-specific differentiation by promoting prespore cell development and inhibiting anterior prestalk-cell development.

Animals↗
PubMed2006

Vitamin B12, folic acid, and the nervous system.

There are many reasons for reviewing the neurology of vitamin-B12 and folic-acid deficiencies together, including the intimate relation between the metabolism of the two vitamins, their morphologically indistinguishable megaloblastic anaemias, and their overlapping neuropsychiatric syndromes and neuropathology, including their related inborn errors of metabolism. Folates and vitamin B12 have fundamental roles in CNS function at all ages, especially the methionine-synthase mediated conversion of homocysteine to methionine, which is essential for nucleotide synthesis and genomic and non-genomic methylation. Folic acid and vitamin B12 may have roles in the prevention of disorders of CNS development, mood disorders, and dementias, including Alzheimer's disease and vascular dementia in elderly people.

Animals↗
PubMed1998

[Folic acid deficiency in chronically hospitalized mental patients].

Studies over the past 30 years have shown a relationship between folic acid deficiency and psychopathology. FA deficiency was observed more often in depressed and in psychotic patients, in alcoholics, in those suffering from organic mental disorders and in the psycho-geriatric population. In a chronic inpatient population of 120 patients, of the 106 in whom FA serum levels were examined, only 1 had a definitely subnormal level. An additional 16 had close to the lower limit of normal (2 ng/ml) and were considered borderline cases. FA-deficient and borderline patients were then compared to matched patients with normal FA levels on the MMSE and PANSS scales by blinded raters. Small differences were found between the 2 groups. The FA-deficient and borderline patients had more organic and psychotic symptoms, but the differences were not statistically significant.

Folic Acid↗
PubMed1997

Activation of the mitogen-activated protein kinase ERK2 by the chemoattractant folic acid in Dictyostelium.

The Dictyostelium MAP kinase ERK2 is activated by extracellular cAMP in aggregation-competent cells and is required for receptor activation of adenylyl cyclase (Maeda, M., Aubry, L., Insall, R., Gaskins, C., Devreotes, P. N., and Firtel, R. A. (1996) J. Biol. Chem. 271, 3351-3354; Segall, J., Kuspa, A., Shaulsky, G., Ecke, M., Maeda, M., Gaskins, C., Firtel, R., and Loomis, W. (1995) J. Cell Biol. 128, 405-413). This cAMP-dependent activation of ERK2 is mediated by the serpentine, G protein-coupled cAMP receptors. However, ERK2 activation by cAMP is at least partially heterotrimeric G protein-independent, with a level of activation in cells lacking the sole Gbeta subunit or the G protein-coupled cAMP receptors-coupled Galpha2 subunit that is approximately 50% that of wild-type cells (Maeda, M., Aubry, L., Insall, R., Gaskins, C., Devreotes, P. N., and Firtel, R. A. (1996) J. Biol. Chem. 271, 3351-3354; Segall, J., Kuspa, A., Shaulsky, G., Ecke, M., Maeda, M., Gaskins, C., Firtel, R., and Loomis, W. (1995) J. Cell Biol. 128, 405-413). Folic acid, a chemoattractant in the vegetative cells that enables amoebae to find bacteria in the wild, also triggers the activation of adenylyl cyclase, which is impaired in the vegetative cells lacking the Galpha protein subunit Galpha4 (Hadwiger, J., Lee, S., and Firtel, R. (1994) Proc. Natl. Acad. Sci. U. S. A. 91, 10566-10570). In this study, we show that folic acid activates ERK2 in developmentally regulated manner and is required for ERK2 stimulation of adenylyl cyclase activity. Maximum levels of folate-stimulated ERK2 activity occur in cells from very early in development, prior to aggregation, and again at the tipped aggregate stages, corresponding to the stages in which folate receptors and the coupled Galpha subunit Galpha4 are maximally expressed. During the activation by folic acid, ERK2 is phosphorylated on tyrosine residue(s) and contemporaneously shows a mobility shift on SDS-PAGE. Interestingly, this activation is not elicited in the absence of Gbeta subunits, in contrast to the response to cAMP. This response also requires the Galpha4 subunit known to be required for other folic acid-mediated responses (Hadwiger, J., Lee, S., and Firtel, R. (1994) Proc. Natl. Acad. Sci. U. S. A. 91, 10566-10570). Furthermore, we show that the activation of ERK2 by cAMP is independent of the Galpha4 subunit, while the activation of ERK2 by folate is independent of Galpha2. Taken together, these data indicate that there are at least two pathways of ERK2 activation, heterotrimeric G protein-dependent and -independent pathways.

Adenylyl Cyclases↗