Evaluation of vitamin B6 intake and status of 20- to 64-year-old Koreans

BACKGROUND/OBJECTIVES: Recent research regarding vitamin B6 status including biochemical index is limited. Thus, this study estimated intakes and major food sources of vitamin B6; determined plasma pyridoxal 5'-phosphate (PLP); and assessed vitamin B6 status of Korean adults. MATERIALS/METHODS: Three consecutive 24-h diet recalls and fasting blood samples were collected from healthy 20- to 64-year-old adults (n = 254) living in the Seoul metropolitan area, cities of Kwangju and Gumi, Korea. Vitamin B6 intake and plasma PLP were analyzed by gender and by vitamin B6 supplementation. Pearson's correlation coefficient was used to determine associations of vitamin B6 intake and plasma PLP. RESULTS: The mean dietary and total (dietary plus supplemental) vitamin B6 intake was 1.94 +/- 0.64 and 2.41 +/- 1.45 mg/day, respectively. Median (50th percentile) dietary intake of men and women was 2.062 and 1.706 mg/day. Foods from plant sources provided 70.61% of dietary vitamin B6 intake. Only 6.3% of subjects consumed total vitamin B6 less than Estimated Average Requirements. Plasma PLP concentration of all subjects was 40.03 +/- 23.71 nmol/L. The concentration of users of vitamin B6 supplements was significantly higher than that of nonusers (P < 0.001). Approximately 16% of Korean adults had PLP levels < 20 nmol/L, indicating a biochemical deficiency of vitamin B6, while 19.7% had marginal vitamin B6 status. Plasma PLP concentration showed positive correlation with total vitamin B6 intake (r = 0.40984, P < 0.0001). CONCLUSIONS: In this study, vitamin B6 intake of Korean adults was generally adequate. However, one-third of subjects had vitamin B6 deficiency or marginal status. Therefore, in some adults in Korea, consumption of vitamin B6-rich food sources should be encouraged.

Effects of Histamine on Cultured Interstitial Cells of Cajal in Murine Small Intestine

Interstitial cells of Cajal (ICCs) are the pacemaker cells in the gastrointestinal tract, and histamine is known to regulate neuronal activity, control vascular tone, alter endothelial permeability, and modulate gastric acid secretion. However, the action mechanisms of histamine in mouse small intestinal ICCs have not been previously investigated, and thus, in the present study, we investigated the effects of histamine on mouse small intestinal ICCs, and sought to identify the receptors involved. Enzymatic digestions were used to dissociate ICCs from small intestines, and the whole-cell patch-clamp configuration was used to record potentials (in current clamp mode) from cultured ICCs. Histamine was found to depolarize resting membrane potentials concentration dependently, and whereas 2-PEA (a selective H1 receptor agonist) induced membrane depolarizations, Dimaprit (a selective H2-agonist), R-alpha-methylhistamine (R-alpha-MeHa; a selective H3-agonist), and 4-methylhistamine (4-MH; a selective H4-agonist) did not. Pretreatment with Ca(2+)-free solution or thapsigargin (a Ca(2+)-ATPase inhibitor in endoplasmic reticulum) abolished the generation of pacemaker potentials and suppressed histamine-induced membrane depolarization. Furthermore, treatments with U-73122 (a phospholipase C inhibitor) or 5-fluoro-2-indolyl des-chlorohalopemide (FIPI; a phospholipase D inhibitor) blocked histamine-induced membrane depolarizations in ICCs. On the other hand, KT5720 (a protein kinase A inhibitor) did not block histamine-induced membrane depolarization. These results suggest that histamine modulates pacemaker potentials through H1 receptor-mediated pathways via external Ca2+ influx and Ca2+ release from internal stores in a PLC and PLD dependent manner.

Suppression of VEGF and Decrease in Vascular Leakage by Pyridoxal 5'-Phosphate in Diabetic Rats

PURPOSE: The authors of the present study investigated whether pyridoxal 5'-phosphate (PLP), an active coenzyme of vitamin B6, could inhibit the development of diabetic retinopathy in streptozotocin (STZ)-induced diabetic rats. METHODS: Seven-week-old Spraque-Dawley rats (n = 20) were used in the present study. STZ (70 mg/kg) was injected intraperitoneally to induce diabetes. Blood glucose and body weight were monitored. Intraperitoneal injections of 5 microg and 50 microg PLP were administered every two days from the second week of induced diabetes. During the third week of PLP injections, the concentration level of plasma homocysteine was measured. In addition, functional status was examined by vitreous fluorophotometer and anatomical status by vascular endothelial growth factor (VEGF) staining in the retina. RESULTS: Based on vitreous fluorophotometry examination, the PLP injection group proved to have a lower level of fluorescein concentration in the vitreous. Additionally, immunohistochemical staining revealed down-regulation of VEGF expression in the PLP group. In addition, the PLP group had a lower plasma homocysteine concentration. However, an over-dosage injection of PLP did not appear to have any noticeable impact on the treatment of diabetes. CONCLUSIONS: PLP, an active coenzyme of vitamin B6, proved to have inhibitory effects on VEGF expression and vascular leakage in the diabetic rat retina.

Assessment of vitamin B6 status in Korean patients with newly diagnosed type 2 diabetes

The purpose of this study was to assess vitamin B6 intake and status in Korean patients with newly diagnosed type 2 diabetes. Sixty-four patients with newly diagnosed type 2 diabetes and 8-11% glycated hemoglobin (A1C), along with 28 age-matched non-diabetic subjects, participated. Dietary vitamin B6 intake was estimated by the 24 hour recall method and plasma pyridoxal 5'-phosphate (PLP) was measured. There was a significant difference in daily total calorie intake between the diabetic and non-diabetic groups (1,917 +/- 376 vs 2,093 +/- 311 kcal). There were no differences in intake of total vitamin B6 (2.51 +/- 0.91 vs 2.53 +/- 0.81 mg/d) or vitamin B6/1,000 kcal (1.31 +/- 0.42 vs 1.20 +/- 0.32 mg) between the diabetic and non-diabetic groups, andI intakes of total vitamin B6 were above the Korean RDA in both groups (180.0 +/- 57.9 vs 179.0 +/- 65.4). There was a higher percentage of diabetic subjects whose plasma PLP concentration was < 30 nmol/L compared to non-diabetic group. Plasma PLP levels tended to be lower in the diabetic subjects than in the non-diabetic subjects, although the difference was not statistically significant due to a large standard deviation (80.0 +/- 61.2 nmol/L vs 68.2 +/- 38.5 nmol/L). Nevertheless, plasma PLP levels should be monitored in pre-diabetic patients with diabetic risk factors as well as in newly diagnosed diabetic patients for long-term management of diabetes, even though this factor is not a major risk factor that contributes to the development of degenerative complications in certain patients.

Vitamin B6 Requirement: Indicators and Factors Affecting

The purpose of this study was to establish the selection of indicators for estimating and factors affecting the requirement of vitamin B6. There has been a need to establish the human requirements of vitamin B6 since vitamin B6 is thought to be involved in more than one hundred biochemical reactions as a coenzyme in the metabolism of amino acids, glucose, and lipid, and the synthesis of neurotransmitters. For the review of the literature, this study included from early findings of the sixties to studies of 2009. This study suggests that plasma pyridoxal 5' phosphate (PLP) is the best single indicator of vitamin B6 status for the healthy but not for the non-healthy. Erythrocyte aspartate aminotransferase and alanine aminotransferase activation by PLP as an indirect measure and urinary 4-pyridoxic acid excretion as a direct measure are useful as supporting indicators. Bioavailability, nutrient interaction, physiological need, and chronic diseases may increase the requirement for vitamin B6. However, these effects can not be quantified due to insufficient evidences.

Effect of Extremely Low Frequency Electromagnetic Fields (EMF) on Phospholipase Activity in the Cultured Cells

This study was conducted to investigate the effects of extremely low frequency electromagnetic fields (EMF) on signal pathway in plasma membrane of cultured cells (RAW 264.7 cells and RBL 2H3 cells), by measuring the activity of phospholipase A2 (PLA2), phospholipase C (PLC) and phospholipase D (PLD). The cells were exposed to the EMF (60 Hz, 0.1 or 1 mT) for 4 or 16 h. The basal and 0.5 microM melittin-induced arachidonic acid release was not affected by EMF in both cells. In cell-free PLA2 assay, we failed to observe the change of cPLA2 and sPLA2 activity. Also both PLC and PLD activities did not show any change in the two cell lines exposed to EMF. This study suggests that the exposure condition of EMF (60 Hz, 0.1 or 1 mT) which is 2.4 fold higher than the limit of occupational exposure does not induce phospholipases-associated signal pathway in RAW 264.7 cells and RBL 2H3 cells.

A Case of Granulicatella adiacens Septicemia Identified by 16S rRNA Sequencing Analysis / 대한임상미생물학회지

Granulicatella adiacens is one of the fastidious gram positive cocci previously described as nutritionally variant streptococci due to their requirement of L-cysteine, pyridoxal, or thiol compounds for growth. These bacteria have been identified as significant causative agents of endocarditis, opthalmic infections, and meningitis. We report a case of septicemia caused by G. adiacens in an 80-year-old patient with cholangiocarcinoma. The organism was identified by phenotypic and 16S rRNA sequencing analyses.

A Case of Cystathioninuria with Delayed Development

Cystathionine is well-known intermediate in the metabolism of methionine. It is cleaved to cysteine and homoserine by gamma-cystathionase. This enzyme utilize pyridoxal 5'-phosphate as coenzyme. gamma-cystathionase deficiency leads to persistent excretion of large amount of cystathionine in urine, as well as to accumulation of cystathionine in body tissues and fluids. It is inherited as an autosomal recessive trait and shows wide variety of clinical manifestations. No clinical abnormality seems to be specifically associated with gamma-cystathionase deficiency. The majority of patients responded to high dose administration of pyridoxine. We report the first case of cystathioninuric patient in Korea, 19 months of female with developmental delay. In brain MRI, there was generalized mild brain atrophy. There were several times of brief paroxysmal generalized polyspike and wave discharges in electroencephalography(EEG). In amino acid analysis of urine, there was elevated level of cystathionine. She was treated with high dose of pyridoxine. In follow up analysis of urinary amino acid, the cystathionine level was markedly decreased to normal range, and EEG was normalized. Her development shows improvement.

Inhibition of gentamicin-induced nephrotoxicity by ascorbic acid and pyridoxal hydrochloride

This study was undertaken to compare the capability of blockade of gentamicin nephrotoxicity by either ascorbic acid [vitamin C] or pyridoxal hydrochloride [vitamin B6] and to evaluate whether their combination has a better protective effect than either alone, as manifested by changes in the serum urea and creatinine levels as well as the histological renal changes. For this purpose, 70 male Wister albino rats were equally divided into 7 groups. A negative control group receiving distilled water, a positive control group receiving vitamin C alone, a positive control group receiving vitamin B6, rats receiving gentamicin alone, rats receiving gentalicin as well as vitamin C, rats receiving gentamicin in addition to vitamin B6, and finally rats receiving gentamicin, vitamin C and vitamin B6. Our results showed that, vitamin B6 plays a better role in the protection against gentamicin nephrotoxicity than vitamin C, moreover, the combination of these two vitamins produced a better protection than either vitamin alone. Strict adherence to the prescribed dose of the aminoglycoside preparations especially gentamicin is required. In addition, a combination of vitamin C and vitamin B6 could provide adequate protection against gentamicin-induced nephrotoxitiy

The study of the catalytic sites of enzymes using fluorescent compounds

The use of fluorescent compounds can be a valuable tool to probe the active site of enzymes. Several examples of this approach are discussed, particularly the use of pyridoxal phosphate analogs. The study of protein-protein interactions by means of fluorescent-labeled proteins is also analyzed

Effects of citrate pyridoxal 5'-phosphate-TRIS(CPT) antivoagulant on spurious low platelet counts caused by EDTA / 대한혈액학회지

No abstract available.