Cultured monkey kidney cells are shown to possess a cell-surface receptor that binds 5-methyltetrahydro[3',5',7,9-3H4]folic acid (5-methyltetrahydro[3H]folic acid) with high affinity (Kd = 3 nM at 4 degrees C). The cell-surface binding capacity for [3H]folic acid or [3H]methotrexate is equivalent to that for 5-methyltetrahydro[3H]folate, but the Kd values are 0.4 and 20 nM, respectively. These ...

OBJECTIVE To characterise plasma and red-blood-cell (RBC) folate status among pregnant women in an area with an extremely high prevalence of neural tube defects, and to compare them with those of women from a low prevalence area. DESIGN A cross-sectional survey conducted in 2003. SETTING One county and one city from each of the high prevalence area and the low prevalence area in China. SU...

High plasma total homocysteine (tHcy) concentration is reported to be a risk factor for vascular diseases. We investigated the extent to which serum folate and plasma tHcy respond to a high intake of natural folate from food. Thirty-seven healthy females volunteered t o participate in a crossover dietary intervention. The study included a baseline period and two 5-week diet periods (low- and hi...

Evidence is accumulating that folate, a B vitamin found in green leafy vegetables, may affect the development of neoplasia. We examined the relationship between folate status and colorectal cancer in a case-control study nested within the Alpha-Tocopherol Beta-Carotene Study cohort of male smokers 50-69 years old. Serum folate was measured in 144 incident cases (91 colon, 53 rectum) and 276 con...

BACKGROUND Serum folate concentration is lower in individuals with the methylenetetrahydrofolate reductase (MTHFR) 677TT genotype than in those with the MTHFR 677CC or 677CT genotypes. Since studies considering folate intake are limited, we examined the association between folate intake and serum folate levels, according to the genotype. METHODS The subjects comprised 170 Japanese persons (74...

BACKGROUND AND OBJECTIVE Nutrient values are influenced by the analytical method used. Food folate measured by high performance liquid chromatography (HPLC) or by microbiological assay (MA) yield different results, with in general higher results from MA than from HPLC. This leads to the question of how to deal with different analytical methods in compiling standardised and internationally compa...

BACKGROUND Folate is involved in DNA synthesis and methylation and may thereby influence carcinogenesis. OBJECTIVES We examined plasma folate (P-folate) concentration in relation to genotypes of the folate-metabolizing enzyme methylenetetrahydrofolate reductase [MTHFR 677C-->T (rs1801133) and 1298A-->C (rs1801131)]. We also explored whether P-folate was associated with risk of postmenopausal ...

Human milk contains both a particulate and a soluble folate binding protein. Following solubilization of the particulate folate binding protein with 1%Triton X-100, the particulate and soluble folate binding proteins were purified 13,000-fold using pteroylglutamic acid-Sepharose as the major purification step. Each of the purified proteins gave a single band on sodium dodecyl sulfatepolyacrylam...

OBJECTIVE To assess the folate status of US women in a study of a folate-fortified oral contraceptive (OC) using the Short Folate Food Frequency Questionnaire and plasma and red blood cell (RBC) folate samples. DESIGN Sub-analysis from a multi-centre, randomised, double-blind, controlled contraceptive trial with assessments at baseline and 6 months. We calculated dietary folate equivalents (D...