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The current study developed a method for quantifying four drugs-Sulfamethoxazole, Trimethoprim, Isoniazid, and Pyridoxine-in rabbit plasma. The method uses gradient liquid chromatography based on analytical quality by design. To achieve separation, a Eclip Plus C18 (250 mm × 5 mm, 4.6 µm) column with L1 packing was used, and analytes were detected at 254 nm at ambient temperature. The optimized mobile phase consisted of 50 mM potassium dihydrogen phosphate buffer (pH 6.5) and Methanol. The concentration of Methanol was 3% (0-5 min), 15% (5-15 min), 55% (15-27 min), and 3% Methanol until the end of the 30-min runtime, and the flow rate was set at 0.95 mL/min. Control Noise Experimentation was used to screen studies, revealing that flow rate, pH, and Methanol concentration significantly affected the analytical attributes. The study identified critical attributes (resolution and asymmetric factor) and developed a quality target method profile. A central composition design was used to optimize the essential parameters. The method developed for the drugs showed peaks at retention times of 6.990 min for Isoniazid, 7.880 min for Pyridoxine, 15.530 min for Sulfamethoxazole, and 26.890 min for Trimethoprim, respectively. The method was validated with linearity in the range of 10-640 ng ml -1 , with R 2 of 0.9993, 0.9987, 0.9993, and 0.9992 for Sulfamethoxazole, Trimethoprim, Isoniazid, and Pyridoxine, respectively., (© 2024. The Author(s).)

Background and Aims: Vitamin B6 is involved in a large spectrum of physiological processes and comprises of the vitamers pyridoxamine (PM), pyridoxal (PL), pyridoxine (PN), and their phosphorylated derivatives including the biological active pyridoxal 5'-phosphate (PLP). While PN toxicity is known to complicate several treatments, PM has shown promise in relation to the treatment of metabolic and age-related diseases by blocking oxidative degradation and scavenging toxic dicarbonyl compounds and reactive oxygen species. We aimed to assess the metabolization of oral PM supplements in a single and three daily dose., Materials and Methods: We optimized and validated a method for the quantification of the B6 vitamers in plasma and urine using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Five healthy volunteers were recruited to study PM metabolization after a single oral dose of 200 mg PM or a three daily dose of 67 mg PM. A third protocol was implemented as control for dietary intake. Venous blood samples, 24 h urine and fasted second void urine samples were collected., Results: After a single oral dose of 200 mg PM, plasma PM increased in the first 3 h to a maximum of 2324 ± 266 nmol/L. While plasma PM levels returned to baseline after ~10 h of PM intake, PLP increased to a maximum of 2787 ± 329 nmol/L and reached a plateau. We found a small increase of PN to a maximum of 13.5 ± 2.1 nmol/L; it was nearly undetectable after ~12 h. With a three daily dose of 67 mg PM we observed an increase and decline of plasma PM, PL, and PN concentrations after each PM intake. PLP showed a similar increase as in the single dose protocol and accumulated over time., Conclusion: In this study we showed high plasma levels of PM after oral PM supplementation. We found steadily increasing levels of the biologically active PLP, with minimal formation of PN. The B6 vitamer PM is an interesting supplement as an inhibitor of harmful processes in metabolic diseases and for the treatment of vitamin B6 deficiency., Clinical Trial Registry: The study was approved by the Medical Ethics Committee of Maastricht University (NL) and was registered at ClinicalTrials.gov as NCT02954588., Competing Interests: Conflicts of interest The authors declare no conflict of interest., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Pyridoxine is an important co-factor for many biochemical reactions in cellular metabolism related to the synthesis and catabolism of amino acids, fatty acids, neurotransmitters. Deficiency of pyridoxine results in impaired transcellular signaling between neurons and presents with muscular convulsions, hyperirritability, and peripheral neuropathy. Deficiency of pyridoxine is usually found in association with other vitamin B deficiencies such as folate (vitamin B9) and cobalamin (vitamin B12). Isolated pyridoxine deficiency is extremely rare. We present the case of a 59-year old female with type 2 diabetes who complained of painful muscle spasms. Her muscle spasms involved in both feet, which have spread proximally to her legs. She also experienced intermittent muscle spasms in her left arm, which is not alleviated by baclofen, cyclobenzaprine. Her plasma pyridoxal 5-phosphate confirmed pyridoxine deficiency. Vitamins B1, B3, B12, and folate were within normal limits. The patient received standard-dose intramuscular pyridoxine injections for three weeks followed by oral supplements for 3 months and her symptoms resolved. This case illustrates the rare instance of isolated pyridoxine deficiency in type 2 diabetes patient manifesting as myoclonic muscle spasms involving the legs and arms in the absence of objective polyneuropathy. Pyridoxine level should, therefore, be assessed in patients with type 2 diabetes, including newly diagnosed patients., (Copyright © 2020 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.)

Objectives: This prospective study aimed to compare changes in serum thiamine and pyridoxine levels of patients who underwent liver transplant or living donor hepatectomy., Materials and Methods: Between January 2013 and November 2013, 35 patients with chronic liver disease who underwent liver transplant (the recipient group) and 30 healthy individuals who underwent living donor hepatectomy (the control group) during the same period were prospectively compared in terms of both preoperative and postoperative serum thiamine and pyridoxine levels. The groups were also subjected to intragroup analysis of preoperative and postoperative changes in serum vitamin levels to determine how a major surgical procedure affected serum vitamin levels. Mann-Whitney U test and Wilcoxon signed-rank test were used for intergroup comparisons and intragroup repeated measurements, respectively., Results: The intergroup comparisons revealed significant differences in favor of the control group with respect to preoperative thiamine (P < .026) and postoperative thiamine (P < .017) levels, whereas there were statistically significant differences in favor of the recipient group with respect to the preoperative pyridoxine (P < .006) and postoperative pyridoxine (P < .001) levels. The intragroup comparisons showed significant increases in serum thiamine (P < .001) and pyridoxine (P < .031) levels compared with the preoperative serum levels of both vitamins at postoperative day 5 in the recipient group. In the control group, serum thiamine level (P < .001) at postoperative day 5 was significantly different from the preoperative level. On the other hand, a drop in serum pyridoxine level was detected at postoperative day 5, although this was not statistically significant (P < .21)., Conclusions: This study showed a lower serum thiamine level but a higher serum pyridoxine level in patients with chronic liver disease versus healthy controls. This difference persisted into the early postoperative period. This study also showed significant increases in thiamine and pyridoxine levels after transplant surgery.

Herein, a fluorimetric sensor was fabricated based on molecularly imprinted polymers (MIPs) with two types of carbon dots as fluorophores. The MIPs produced had similar excitation wavelengths (400 nm) and different emission wavelengths (445 and 545 nm). They were used for the simultaneous analysis of levodopa and pyridoxine. First, two types of carbon dots, i.e. nitrogen-doped carbon dots (NCDs) with a quantum yield of 43%, and carbon dots from o-phenylenediamine (O-CDs) with a quantum yield of 17%, were prepared using the hydrothermal method. Their surfaces were then covered with MIPs through the reverse microemulsion method. Finally, a mixture of powdered NCD@MIP and O-CD@MIP nanocomposites was used for the simultaneous fluorescence measurement of levodopa and pyridoxine. Under optimal conditions using response surface methodology and Design-Expert software, a linear dynamic range of 38 to 369 nM and 53 to 457 nM, and detection limits of 13 nM and 25 nM were obtained for levodopa and pyridoxine, respectively. The capability of the proposed fluorimetric sensor was investigated in human blood serum and urine samples. Graphical Abstract Schematic representation of nitrogen-doped carbon dots (NCDs), carbon dots from o-phenylenediamine (O-CDs), NCDs coated with imprinted polymers (NCD@MIPs), and O-CDs coated with imprinted polymers (O-CD@MIPs) in the presence and absence of levodopa and pyridoxine.

Background: Migraine, especially migraine with aura (MA), has been linked to increased risk for ischemic cerebrovascular disease. The possible role of elevated serum homocysteine (Hcy, a cause of thrombophilia) in migraine has been demonstrated by several studies., Objective: The present study aims to review and meta-analyze data from studies investigating the difference of serum Hcy and Hcy lowering vitamins between migraine patients and healthy controls (HC), as well as between patients with MA and migraine without aura (MO)., Methods: Literature search involved MEDLINE, Embase, CENTRAL, Google Scholar, and trial registries. The Newcastle-Ottawa Scale was used to evaluate the quality of the retrieved studies. Standardized mean differences (SMDs) and 95% confidence intervals (95%CIs) were calculated. Funnel-plots were utilized for the evaluation of publication bias., Results: Overall, 29 (28 case-control and 1 cross-sectional) studies were retrieved. Meta-analysis was indicative of higher Hcy concentration in migraine patients vs HC overall [adults and children: 16 studies, I 2  = 81%, SMD = 0.41, 95%CI = (0.20, 0.61)]. Hcy was consistently elevated in adults with migraine [adults: 12 studies, I 2  = 76%, SMD = 0.35, 95%CI = (0.15, 0.54); children: 1 study, SMD = 0.37, 95%CI = (-0.05, 0.79)]. Subgroup analyses reproduced the results for both adults with MA [7 studies, I 2  = 83%, SMD = 0.37, 95%CI = (0.03, 0.71)] and MO [5 studies, I 2  = 84%, SMD = 0.46, 95%CI = (0.03, 0.89)]. Figures for serum folate were lower in the overall comparison of migraine patients with HC [adults and children: 11 studies, I 2  = 87%, SMD = -0.36, 95%CI = (-0.68, -0.05); adults: 8 studies, I 2  = 6%, SMD = -0.11, 95%CI = (-0.22, 0.01); children: 1 study, SMD = -0.71, 95%CI = (-1.14, -0.29); MA adults: 4 studies, I 2  = 44%, SMD = -0.16, 95%CI = (-0.35, 0.04); MO adults: 4 studies, I 2  = 47%, SMD = -0.17, 95%CI = (-0.44, 0.10)]. Serum vitamin B12 levels were not different between migraine patients and HC [adults and children: 11 studies, I 2  = 88%, SMD = -0.24, 95%CI = (-0.57, 0.09); adults: 8 studies, I 2  = 57%, SMD = -0.10, 95%CI = (-0.28, 0.08); children: 1 study, SMD = 0.29, 95%CI = (-0.13, 0.71); MA adults: 4 studies, I 2  = 63%, SMD = -0.14, 95%CI = (-0.48, 0.20); MO adults: 4 studies, I 2  = 59%, SMD = -0.15, 95%CI = (-0.45, 0.15)]. Serum Hcy was lower in MO than MA [adults and children: 10 studies, I 2  = 39%, SMD = 0.30, 95%CI = (0.14, 0.46), adults: 6 studies, I 2  = 29%, SMD = 0.21, 95%CI = (0.09, 0.36), children: 1 study, SMD = 0.51, 95%CI = (0.22, 0.80)]. Serum folate and vitamin B12 did not differ between MA and MO., Conclusions: Our results suggest that there is a possible link between migraine, mainly MA, and elevated serum Hcy., (© 2020 American Headache Society.)

A 64-year-old woman developed symptoms of vomiting and tonic-clonic convulsions 9.5 h after eating 50 roasted Ginkgo biloba seeds with 100 g of alcohol. The intravenous administration of pyridoxal phosphate effectively improved the symptoms. Blood samples were collected and stored over 35 h. The assessment of 4'-O-methylpyridoxine and vitamin B6 vitamers indicated high levels of both, but the pyridoxal phosphate levels were low during the acute stage. These results suggest that 4'-O-methylpyridoxine inhibits the transformation of vitamin B6 analogues to the active form, pyridoxal phosphate. In our case, alcohol may have extended the period until ginkgo intoxication appeared.

Recently, connections have been made between feeding and eating problems and autism spectrum disorder (ASD) and between autism pathophysiology and diet issues. These could explain some of the mechanisms which have not yet been discovered or are not sufficiently characterized. Moreover, there is an increased awareness for micronutrients in ASD due to the presence of gastrointestinal (GI) problems that can be related to feeding issues. For example, levels of vitamins B 1 , B 6 , B 12 , A and D are often reported to be low in ASD children. Thus, in the present mini review we focused on describing the impact of some vitamins deficiencies and their relevance in ASD patients., Competing Interests: The authors declare no conflict of interest.

So far, there have been no analyses of correlations between the level of water-soluble vitamins in women with polycystic ovary syndrome (PCOS) and hormone and lipid profiles as well as carbohydrate metabolism. The unpopular concept that PCOS may also be conditioned by a chronic infection leads to a suspicion that water-soluble vitamins may be involved in the struggle against PCOS. This is why the aim of this research was to determine whether there are any indications that could confirm this hypothesis. The study included 64 women of Caucasian race: 50 patients aged 29.52 ± 7.01 years with PCOS, diagnosed according to the Rotterdam criteria. The control group consisted of 14 women aged 30.23 ± 6.3 years with correct BMI. HPLC Infinity1260 Binary LC (Agilent Technologies, Waldbronn, Germany) was used to analyze nine vitamins. The vitamins were separated using the gradient method, a buffer of 25 mM HK2PO4 with pH equal to 7.0, and 100 % methanol buffer. The acquired results were compared using Statistica 12.0 (Statsoft, Tulsa, Oklahoma, USA). Non-parametric tests were used: Mann-Whitney tests for comparisons between groups (PCOS and control group, CG), in which p < 0.05 was considered statistically significant. Subsequently, we performed a correlation matrix of the biochemical parameters of blood with vitamins at p ≤ 0.05. Higher concentrations of ascorbic acid were observed in PCOS. The content of the remaining vitamins was higher in the control group, and the statistical differences were significant in reference to thiamine, riboflavin, pyridoxine and folic acid in comparison to the control group. A significant positive correlation was observed between vitamin C and testosterone/insulin, another between riboflavin and androstenedione/testosterone, next between biotin and thyrotropic hormone (TSH), between pantothenic acid and dehydroepiandrosteron (DHEA-SO4), and finally between pyridoxine and androstenedione. A negative correlation was observed in the case of niacin with sex hormone binding protein (SHBG) and high density lipoprotein (HDL). Water-soluble vitamins play an important role in the therapy of women with PCOS through the reduction of antioxidative stress and low-intensity inflammation caused by various factors, including chronic infection., Competing Interests: Declaration of Competing Interest The authors have not reported any conflict of interest., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objectives: Mental health disorders are major contributors to disease burden in older people. Deficient status of folate and the metabolically related B vitamins may be implicated in these conditions. This study aimed to investigate folate, vitamin B 12 , vitamin B 6 , and riboflavin in relation to depression and anxiety in aging and also considered the role of fortified foods as a means of optimizing B-vitamin status and potentially reducing the risk of these mental health disorders., Design: The Trinity Ulster Department of Agriculture (TUDA) aging study was a cross-sectional cohort study., Setting and Participants: Community-dwelling adults (n = 5186; ≥60 years) recruited from 2 jurisdictions within the island of Ireland from 2008 to 2012., Measures: Depression and anxiety were assessed using the Centre for Epidemiological Studies Depression (CES-D) and the Hospital Anxiety and Depression (HAD) scales, respectively. The following B-vitamin biomarkers were measured: red blood cell folate, serum total vitamin B 12 , plasma pyridoxal-5-phosphate (PLP; vitamin B 6 ), and erythrocyte glutathione reductase activation coefficient (EGRac; riboflavin)., Results: Biomarker values in the lowest 20% of status for folate (odds ratio [OR] 1.79; 95% CI 1.23-2.61), vitamin B 6 (OR 1.45, 95% CI 1.01-2.06), or riboflavin (OR 1.56, 95% CI 1.10-2.00), but not vitamin B 12 , were each associated with an increased risk of depression (CES-D score ≥16). Correspondingly, B vitamin-fortified foods if consumed daily were associated with a reduced risk of depression (OR 0.54, 95% CI 0.41-0.70). A deficient status of vitamin B 6 (OR 1.73, 95% CI 1.07-2.81), but not other vitamins, was associated with increased anxiety., Conclusions/implications: Better B-vitamin status may have a role in impacting positively on mental health in older adults. Regular intake of fortified foods can provide a means of optimizing B-vitamin status and thus could contribute to reducing depression. If confirmed by a randomized trial, these results may have implications for nutrition and mental health policy, and thus quality of life, in older people., (Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.)

Vitamin B deficiency in patients with inflammatory bowel disease (IBD) is well-documented; however, few studies have explored genomic damage in patients with IBD using the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay. This study investigated the frequency of micronuclei (MNi) using the CBMN-Cyt assay and the level of vitamin B in patients with IBD. This prospective study was conducted in 15 patients with ulcerative colitis, 15 patients with Crohn's disease, and 30 healthy controls from one tertiary hospital. Serum vitamin B and homocysteine levels were measured, and the MNi status was analyzed using the CBMN-Cyt assay. The patients with IBD showed significantly lower serum pyridoxine levels and significantly higher homocysteine levels than controls. The frequencies of binucleated cells (BNCs) with MNi, nucleoplasmic bridges (NPBs), and nuclear buds (Nbuds) were 8.5 [5.8-13.5], 1.0 [0.0-1.9], and 5.4 [4.3-7.4] for the IBD group, and 5.9 [4.8-7.7], 0.2 [0.0-1.0], and 3.5 [2.9-5.4] for the control group (P =  0.011, P =  0.010, and P =  0.002), respectively. This study suggests that patients with IBD have increased frequencies of MNi and decreased levels of pyridoxine than healthy controls., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: In our study, we aimed to evaluate the serum homocysteine levels, pyridoxine, folate and vitamin B12 levels in children with attention deficit hyperactivity disorders (ADHD)., Subjects and Methods: This study included 30 newly diagnosed drug-naive children with ADHD (23 males and 7 female, mean age 9.3±1.8 years) and 30 sex-and age matched healthy controls. The diagnosis of ADHD was made according to DSM-V criteria. Children and adolescents were administered the Schedule for Affective Disorders and Schizophrenia for School Aged Children, Present and Lifetime Version, the Conners' Parent Rating Scale-Revised, Long Form, the Conners' Teacher Rating Scale and the Wechsler Intelligence Scale for Children Revised (WISC-R) for all participants. Homocysteine, pyridoxine, folate and vitamin B12 levels were measured with enzyme-linked immunosorbent assay., Results: Homocysteine, pyridoxine, folate and vitamin B12 levels were significantly lower in children with ADHD compared with their controls (p<0.05). A positive significant correlation was observed between the all WISC-R scores and vitamin B12 level in patients (r=0.408, p=0.025)., Conclusions: The results obtained in this study showed that reduced homocysteine, pyridoxine, folate and vitamin B12 levels could be a risk factor in the etiology of ADHD.

Background: Continuous renal replacement therapy (CRRT) is commonly used to provide renal replacement therapy in the intensive care unit. Limited published data suggest that CRRT may lead to depletion of water-soluble vitamins and trace elements. The goal of this study was to identify the incidence of trace element and vitamin deficiencies in critically ill patients during CRRT., Materials and Methods: This study is based on a retrospective chart review of patients who were referred to Emory University Hospital's nutrition support services and had at least 1 serum micronutrient level measured during CRRT (thiamin, pyridoxine, ascorbic acid, folate, zinc, and copper) between April 1, 2009, and June 1, 2012., Results: Seventy-five patients were included in the study. Nine of 56 patients (16%) had below-normal whole blood thiamin concentrations, and 38 of 57 patients (67%) had below-normal serum pyridoxine levels. Serum ascorbic acid and folate deficiencies were identified among 87% (13 of 15) and 33% (3 of 9) of the study patients, respectively. Nine of 24 patients had zinc deficiency (38%), and 41 of 68 patients had copper deficiency (60%). Of the 75 total subjects, 60 patients (80%) had below-normal levels of at least 1 of the micronutrients measured., Conclusions: The incidence of various micronutrient deficiencies in critically ill patients who required CRRT was higher than previously reported. Prospective studies are needed to determine the impact of CRRT on micronutrient status and the potential clinical and metabolic efficacy of supplementation in the intensive care unit setting., (© 2017 American Society for Parenteral and Enteral Nutrition.)

Pyridoxal 5'-phosphate (PLP), the metabolically active form of vitamin B6, plays an essential role in brain metabolism as a cofactor in numerous enzyme reactions. PLP deficiency in brain, either genetic or acquired, results in severe drug-resistant seizures that respond to vitamin B6 supplementation. The pathogenesis of vitamin B6 deficiency is largely unknown. To shed more light on the metabolic consequences of vitamin B6 deficiency in brain, we performed untargeted metabolomics in vitamin B6-deprived Neuro-2a cells. Significant alterations were observed in a range of metabolites. The most surprising observation was a decrease of serine and glycine, two amino acids that are known to be elevated in the plasma of vitamin B6 deficient patients. To investigate the cause of the low concentrations of serine and glycine, a metabolic flux analysis on serine biosynthesis was performed. The metabolic flux results showed that the de novo synthesis of serine was significantly reduced in vitamin B6-deprived cells. In addition, formation of glycine and 5-methyltetrahydrofolate was decreased. Thus, vitamin B6 is essential for serine de novo biosynthesis in neuronal cells, and serine de novo synthesis is critical to maintain intracellular serine and glycine. These findings suggest that serine and glycine concentrations in brain may be deficient in patients with vitamin B6 responsive epilepsy. The low intracellular 5-mTHF concentrations observed in vitro may explain the favourable but so far unexplained response of some patients with pyridoxine-dependent epilepsy to folinic acid supplementation.

Pyridorin ® , a naturally occurring metabolite of vitamin B6 that inhibits and scavenges reactive oxygen species, is being developed as a potential therapeutic for acute kidney injury. An investigational new drug application (IND) was opened for Pyridorin in support of its ongoing oral drug clinical development program. Currently, a Pyridorin intravenous (IV) formulation is being developed for use in surgical patients. To support the IND for Pyridorin, a full battery of nonclinical Good Laboratory Practice compliant studies was performed with no neurological or behavioral signs of toxicity seen following oral or IV administration of pyridoxine dihydrochloride (the active ingredient in Pyridorin). However, excessive ingestion of vitamin B6 has been reported to cause neurotoxic syndrome in humans. Therefore, under Food and Drug Administration recommendation, a 7-day IV study in rats was conducted to further evaluate the drug's potential to cause neurotoxicity. Blood plasma samples indicated that exposure to pyridoxamine dihydrochloride and its metabolites, pyridoxal, pyridoxine, and 4-pyridoxic acid was linearly dose proportional and independent of gender. At doses of up to 200 mg/kg/day pyridoxine dihydrochloride, no treatment-related effects were seen in rats, providing further evidence for the absence of pyridoxine dihydrochloride-related changes in the nervous system. A no observed adverse effect level of 200 mg/kg/day was identified for this study.

Experimental studies suggest a protective effect of B-vitamins on breast cancer risk, potentially modulated by alcohol intake. However, epidemiological studies are limited, especially regarding non-folate B-vitamins. Furthermore, few studies included quantitative assessment of supplemental intake. This prospective study aimed to investigate the associations between intakes of B-vitamins (dietary, supplemental, total) and breast cancer risk. 27,853 women aged ≥45 years from the NutriNet-Santé cohort (2009-2016) were included, with a median follow-up time of 4.2 years. Dietary data were collected using repeated 24 h records. A specific questionnaire assessed dietary supplement use over a 12-month period. A composition database of 8000 supplements was developed. Associations were characterized by multivariable Cox models, and 462 incident breast cancers were diagnosed. Dietary (HR Q4vs.Q1 = 0.74 (0.55, 0.99), P -trend = 0.05), supplemental (HR Q4vs.Q1 = 0.61 (0.38, 0.98), P -trend = 0.05), and total (HR Q4vs.Q1 = 0.67 (0.50, 0.91), P -trend = 0.01) pyridoxine intakes were inversely associated with breast cancer risk. Total thiamin intake was borderline inversely associated with breast cancer risk (HR per 1-unit increment = 0.78 (0.61, 1.00), P = 0.05). Statistically significant interactions between alcohol consumption and B-vitamin (thiamin, riboflavin, niacin, pantothenic acid, pyridoxine, folate, and cobalamin) supplemental intake were observed, the latter being inversely associated with breast cancer risk in non-to-low alcohol drinkers but not in higher drinkers. This large prospective study, including quantitative assessment of supplemental intake, suggests a potential protective effect of pyridoxine and thiamin on breast cancer risk in middle-aged women.

We describe the case of a malnourished 48-year-old man who had previously undergone a Billroth II procedure for severe peptic ulcer disease. He was found to have a severely stenotic gastrojejunal anastomosis with inflamed mucosa that prevented him from tolerating solid food. Laboratory assessment revealed deficiencies in thiamin, pyridoxine, vitamin D, and carotene. This case demonstrates potential vital micronutrient complications following a partial gastrectomy.

Background: Recent decades have unravelled the molecular background of a number of inborn errors of metabolism (IEM) causing vitamin B6-dependent epilepsy. As these defects interfere with vitamin B6 metabolism by different mechanisms, the plasma vitamin B6 profile can give important clues for further molecular work-up. This has so far been investigated in only a small number of patients., Methods: We evaluated the vitamin B6 vitamers pyridoxal 5'-phosphate (PLP), pyridoxal (PL), pyridoxamine (PM), pyridoxine (PN) and the catabolite pyridoxic acid (PA) in the so far largest patient cohort: reference (n = 50); pyridox(am)ine 5'-phosphate oxidase (PNPO) deficiency (n = 6); antiquitin (ATQ) deficiency (n = 21); tissue non-specific alkaline phosphatase (TNSALP) deficiency (n = 2) and epileptic encephalopathy (EE) of unknown etiology tested negative for ATQ and PNPO deficiency (n = 64)., Results: High plasma PM concentration was found in all patients with PNPO deficiency irrespective of vitamin B6 supplementation. Their PM concentration and the PM/PA ratio was significantly higher (p < 0.0001), compared to any other patients analysed. One patient with TNSALP deficiency and sampling prior to PN supplementation had markedly elevated plasma PLP concentration. On PN supplementation, patients with TNSALP deficiency, ATQ deficiency and patients of the EE cohort had similar plasma vitamin B6 profiles that merely reflect the intake of supra-physiological doses of vitamin B6. The interval of sampling to the last PN intake strongly affected the plasma concentrations of PN, PL and PA., Conclusions: PM concentrations and the PM/PA ratio clearly separated PNPO-deficient patients from the other cohorts. The plasma PM/PA ratio thus represents a robust biomarker for the selective screening of PNPO deficiency.

Isoniazid exposure causes dose-dependent pyridoxine deficiency. Recently, the recommended dosage of isoniazid in children was increased from 5 (4-6) to 10 (10-15) mg/kg/day. We aimed to analyze longitudinally pyridoxine levels in a cohort of previously healthy children and adolescents treated with isoniazid. Mild symptom-free pyridoxine deficiency was observed in 4/75 (5.6%) and 3/40 (7.5%) at baseline and at 3-month follow-up, respectively. Classical age-related risk factors identified patients at risk of pyridoxine deficiency. Our preliminary results support current recommendations regarding pyridoxine supplementation in healthy children.

An 8-year-old girl treated at our facility for superrefractory status epilepticus was found to have a low pyridoxine level at 5 μg/L. After starting pyridoxine supplementation, improvement in the EEG for a 24-hour period was seen. We decided to look at the pyridoxine levels in adult patients admitted with status epilepticus. We reviewed the records on patients admitted to the neurological ICU for status epilepticus (SE). Eighty-one adult patients were identified with documented pyridoxine levels. For comparison purposes, we looked at pyridoxine levels in outpatients with epilepsy (n=132). Reported normal pyridoxine range is >10 ng/mL. All but six patients admitted for SE had low normal or undetectable pyridoxine levels. A selective pyridoxine deficiency was seen in 94% of patients with status epilepticus (compared to 39.4% in the outpatients) which leads us to believe that there is a relationship between status epilepticus and pyridoxine levels., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Setting: Distal sensory polyneuropathy (DSP) may manifest in human immunodeficiency virus (HIV) infected individuals before or after antiretroviral therapy (ART). DSP can also occur in response to isoniazid (INH); this can be prevented by pyridoxine supplementation. N-acetyltransferase 2 (NAT2) polymorphisms influence drug acetylation and possibly the risk for INH-associated DSP., Objective: To investigate the relationship between previous/current TB, pyridoxine deficiency and DSP in HIV-infected individuals enrolled in a government-sponsored HIV programme., Design: Neuropathy assessments were performed among 159 adults pre-ART and 12 and 24 weeks thereafter. DSP was defined as ⩾1 neuropathic symptom and sign. NAT2 genotypes predicted acetylation phenotype. Serum pyridoxine levels (PLP) were quantified at baseline and week 12., Results: DSP was present in 16% of individuals pre-ART and was associated with previous/current TB (P = 0.020). Over 50% were pyridoxine deficient (PLP < 25 nmol/l), despite supplementation with vitamin B complex supplements (2-4 mg/day pyridoxine). Those with a history of TB and pre-ART DSP were more likely to be pyridoxine deficient (P = 0.029), and slow/intermediate NAT2 phenotypes impacted on their PLP levels. Incident/worsening DSP after ART developed in 21% of the participants. PLP levels remained low after ART, particularly among those with prior TB, but without an association between DSP or NAT2 phenotypes., Conclusion: Adequate pyridoxine supplementation before ART initiation should be prioritised, particularly in those with a history of TB or current TB.

Background: Low chronic vitamin B-6 status can occur in a subset of women who use oral contraceptives (OCs) with uncertain metabolic consequences. An insufficiency of cellular pyridoxal 5'-phosphate (PLP), which is the coenzyme form of vitamin B-6, may impair many metabolic processes including one-carbon and tryptophan metabolism., Objective: We investigated the effects of vitamin B-6 supplementation on the in vivo kinetics of one-carbon metabolism and the concentration of one-carbon and tryptophan metabolites in vitamin B-6-deficient OC users., Design: A primed, constant infusion of [(13)C5]methionine, [3-(13)C]serine, and [(2)H3]leucine was performed on 10 OC users (20-40 y old; plasma PLP concentrations <30 nmol/L) before and after 28 d of supplementation with 10 mg pyridoxine hydrochloric acid/d. In vivo fluxes of total homocysteine remethylation, the remethylation of homocysteine from serine, and rates of homocysteine and cystathionine production were assessed. Targeted metabolite profiling was performed, and data were analyzed by using orthogonal partial least-squares-discriminant analysis and paired t tests adjusted for multiple testing., Results: Pyridoxine supplementation increased the mean ± SD plasma PLP concentration from 25.8 ± 3.6 to 143 ± 58 nmol/L (P < 0.001) and decreased the leucine concentration from 103 ± 17 to 90 ± 20 nmol/L (P = 0.007) and glycine concentration from 317 ± 63 to 267 ± 58 nmol/L (P = 0.03). Supplementation did not affect in vivo rates of homocysteine remethylation or the appearance of homocysteine and cystathionine. A multivariate analysis showed a clear overall effect on metabolite profiles resulting from supplementation. Leucine, glycine, choline, cysteine, glutathione, trimethylamine N-oxide, and the ratios glycine:serine, 3-hydroxykynurenine:kynurenine, 3-hydroxykynurenine:3-hydroxyanthranilic acid, and 3-hydroxykynurenine:anthranilic acid were significant discriminating variables., Conclusions: Consistent with previous vitamin B-6-restriction studies, fluxes of one-carbon metabolic processes exhibited little or no change after supplementation in low-vitamin B-6 subjects. In contrast, changes in the metabolic profiles after supplementation indicated perturbations in metabolism, suggesting functional vitamin B-6 deficiency. This study was registered at clinicaltrials.gov as NCT01128244., (© 2015 American Society for Nutrition.)

Food poisoning from Ginkgo biloba seeds can cause epilepsy because of a decrease in γ-aminobutyric acid (GABA) concentrations in the brain. We previously demonstrated that 4'-O-methylpyridoxine (MPN) is responsible for this observed toxicity of G biloba seeds; however, the mechanism for the decrease in GABA and plasma concentration profile of MPN has not been clarified. Our hypothesis is that MPN induces a decrease in vitamin B6 concentrations, resulting in a decrease in GABA concentration. This study aimed to characterize the plasma concentration profile of MPN and intrinsic vitamin B6 concentrations (pyridoxal [PL], PL-5'-phosphate [PLP], and 4-pyridoxic acid) using a rat model. Plasma concentrations of B6 vitamers after intravenous MPN administration (5 mg/kg) were determined using high-performance liquid chromatography with a fluorescence detector. The half-life of MPN (0.91 ± 0.05 hours) was shorter in rats than the previously reported value in humans. We found a significant decrease in the plasma concentration of PLP, an active form of vitamin B6, after MPN administration. We also observed an increase in plasma PL and 4-pyridoxic acid concentrations; the increase in PL concentration may be caused by either metabolism of MPN to PL or by MPN-mediated inhibition of PL kinase. The present study is the first in vivo study showing relatively rapid elimination of MPN in rats and a decrease in plasma PLP concentration caused by MPN., (Copyright © 2015 Elsevier Inc. All rights reserved.)

An 11-year-old male with autism became less responsive and was hospitalized with hepatomegaly and liver dysfunction, as well as severe lactic acidosis. His diet for several years was self-limited exclusively to a single "fast food"-a particular type of fried chicken-and was deficient in multiple micronutrients, including the B vitamins thiamine and pyridoxine. Lactic acidosis improved rapidly with thiamine; 2 weeks later, status epilepticus-with low serum pyridoxine-resolved rapidly with pyridoxine. Dietary B vitamin deficiencies complicated the care of this critically ill autistic child and should be considered in this setting., (© 2014 American Society for Parenteral and Enteral Nutrition.)

Vitamin B6 has been known to possess antiemetic effects since 1942. This water soluble compound has several forms in the circulation including pyridoxine, pyridoxal, and pyridoxal phosphate. The active antiemetic form of vitamin B6 is unknown. This was a pre-specified substudy of a randomized, placebo-controlled trial comparing the antiemetic effect of the doxylamine-vitamin B6 combination (Diclectin®) (n = 131) to placebo (n = 126) in women with nausea and vomiting of pregnancy. Serum concentrations of pyridoxine, pyridoxal, and pyridoxal 5' phosphate (PLP) and doxylamine were measured on Days 4, 8, and 15. With Diclectin® exhibiting a significant antiemetic effect in pregnancy, serum concentrations of pyridoxine were unmeasurable in almost all patients and those of pyridoxal were undetectable in half of patients. In contrast, PLP was measurable at sustained, stable steady-state levels in all patients. Our data suggest that there is a correlation between PLP levels and PUQE score of morning sickness symptoms when pyridoxine and pyridoxal levels are undetectable, and hence they might be prodrugs of PLP, which may be the active antiemetic form of vitamin B6., (© 2014, The American College of Clinical Pharmacology.)

Background/objectives: Folate, pyridoxine and cobalamin are coenzymatically essential in one-carbon methyl metabolism, and their deficiencies could explain some alterations during breast carcinogenesis. We aimed to evaluate the validity of folate, pyridoxine and cobalamin estimates from a food frequency questionnaire (FFQ) on the basis of their corresponding fasting plasma biomarkers, in breast cancer (BC) patients., Subjects/methods: In a prospective, consecutive case series, 149 women with primary BC aged between 30 and 69 years as a representative sample of Iranian women with BC were recruited. The 136-item FFQ was used for the validity assay. Fasting plasma folate and cobalamin were tested by automated electrochemiluminescence. The high-pressure liquid chromatography with fluorescence detection was used to determine the plasma levels of pyridoxal-5'-phosphate (PLP) and total homocysteine (tHcy)., Results: Area under the curve (AUC) for assessing the diagnostic accuracy of folate-related data through an FFQ was 0.74 (P<0.01) in the reference model (folate plasma level<5.9 ng/ml), with sensitivity and specificity of 68% and 63%, respectively. The positive and negative predictive values (PPV and NPV) were 96.9% and 96.8%, respectively. The AUC for cobalamin intake in the reference model (plasma cobalamin<260 pmol/l) was 0.64 (P<0.01), with 60% sensitivity and 61% specificity. Although tHcy ≥10.0 μmol/l was used as reference indicator, the folate intake (AUC=0.71, P<0.01) and cobalamin intake status (AUC=0.67, P<0.05) were also determined appropriately by FFQ., Conclusions: Dietary folate and cobalamin estimates from FFQ were significantly correlated with their fasting plasma concentrations. Our data supported the validity of new FFQ to rank individuals by dietary intake status of folate and cobalamin.

Recently the elevated plasma total homocysteine (tHcy) concentration has been concerned as the secondary feature of tumoral proliferation and enhances the likelihood of thrombogenesis in cancer patients. The objective of this study was to determine the associations between folate, cobalamin, and pyridoxine with fasting plasma tHcy concentration in breast cancer (BC) patients. The intake levels of nutrients were assessed using a validated food frequency questionnaire in 141 newly diagnosed BC patients. The plasma tHcy and pyridoxal-5-phosphate were measured using high performance liquid chromatography with fluorescence detector. Plasma tHcy levels were observed to be significantly higher among BC participants with Stage III where the plasma concentrations of folate was also comparatively less (P < 0.05) than other stages. Dietary pyridoxine was even being consumed less at this stage (P < 0.05). The plasma, dietary, and residual variables of folate were inversely correlated with plasma tHcy concentration (P < 0.05). Dietary cobalamin was also associated negatively with tHcy (P < 0.05). The odds ratio of comparing the highest tertile of plasma cobalamin (>394 pmol/l) and folate (>11.4 ng/ml) vs. the lowest categories were associated with reduced odds of high tHcy occurrence with 0.20 (95% confidence interval: 0.04-0.98) and 0.14 (95% confidence interval: 0.03-0.64), respectively. In conclusion, nutrition-related methyl-group insufficiency could lead to imbalance in tHcy metabolism, as a possible cancer marker.

Most bioequivalence (BE) studies are conducted in males with the assumption that variability in pharmacokinetics is similar between the sexes. The purpose of this single-center, reference replicate study was to determine the effect of sex on the pharmacokinetics and BE of doxylamine-pyridoxine 10 mg-10 mg delayed-release tablets. Healthy males (n = 12) and non-pregnant females (n = 12) were administered two tablets, and blood sampling was conducted from 1 hour pre-dose until 72 hours post-dose. After 21 days, dose administration and blood sampling were re-conducted. All analytes were measured using liquid chromatography-tandem mass-spectrometry. Pharmacokinetic parameters were calculated for each study period using standard, non-compartmental methods, and differences were assessed using ANOVA. BE testing was conducted using the relative 90% confidence interval for the AUC0-t for each analyte. Females had significantly larger AUC0-t for doxylamine, 1,550 ng h/mL (coefficient of variance [CV = 19%]) versus 1,272 ng h/mL (CV = 21%; P ≤ .05), and pyridoxine, 35 ng h/mL, (CV = 43%) versus 25 ng h/mL (CV = 31%; P ≤ .05) compared to males. A higher Cmax for doxylamine was observed in females, 107 ng/mL (CV = 16%), compared to males, 86 ng/mL (CV = 15%) (P ≤ .05). BE testing did not demonstrate bioequivalence between males and females. Pharmacokinetic differences observed between the sexes have implications for future BE studies using doxylamine-pyridoxine., (© 2013, The American College of Clinical Pharmacology.)

Vitamin B6 (pyridoxine) is closely associated with the functions of the nervous, immune and endocrine systems. It also participates in the metabolic processes of proteins, lipids and carbohydrates. Pyridoxine deficiency may result in neurological disorders including convulsions and epileptic encephalopathy and may lead to infant abnormalities. The Intravenous administration of pyridoxine to patients results in a dramatic cessation of seizures. A number of analytical methods were developed for the determination of pyridoxine in different dosage forms, food materials and biological fluids. These include UV spectrometric, spectrofluorimetric, mass spectrometric, thin-layer and high-performance liquid chromatographic, electrophoretic, electrochemical and enzymatic methods. Most of these methods are capable of determining pyridoxine in the presence of other vitamins and complex systems in µg quantities. The development and applications of these methods in pharmaceutical and clinical analysis mostly during the last decade have been reviewed.

Although Diclectin (doxylamine/pyridoxine delayed-released combination) is widely used in Canada, its pharmacokinetics (PK) during pregnancy has never been described. The objective of this study was to compare the PK of doxylamine/pyridoxine delayed-released combination in pregnant versus nonpregnant women. The apparent clearances (CL) of doxylamine and pyridoxal 5'-phosphate (PLP; the active metabolite of vitamin B(6) ) during the first-trimester pregnancy in women who participated in a Diclectin randomized trial were compared with those of healthy, adult, nonpregnant women who participated in a voluntary PK trial. Eighteen nonpregnant women were compared with 50 pregnant women who were treated with Diclectin. There was no difference in the apparent CL of doxylamine in women in their first trimester of pregnancy when compared with nonpregnant women on day 4 (median = 196.7 vs 249.5 mL/h/kg, respectively, P = .065), day 8 (median = 248.4 vs 249.5 mL/h/kg, respectively, P = .82), and day 15 (median = 200.9 vs 249.5 mL/h/kg, respectively, P = .55). No difference was found in the apparent CL of PLP on day 15 (median = 342.3 vs 314.7 mL/h/kg, respectively, P = .92). There was no pregnancy-induced effect in the apparent CL of either doxylamine or PLP in women during the first trimester of pregnancy despite the existence of morning sickness., (© The Author(s) 2013.)

Objective: The study aimed to determine vitamin B6 status in elderly (age ≥ 60 years) and younger (age <60 years) recipients of allogeneic kidney graft and to investigate associations between vitamin B6 status and immunity markers., Design: A retrospective observational study., Setting: The study was conducted at the Medical University of Gdańsk, Poland., Subjects: We recruited 34 kidney allograft recipients (17 males and 17 females) and allocated them into 2 groups: patients aged ≥ 60 years (18 patients) and those aged <60 years (16 patients). Exclusion criteria included patients receiving vitamin B6 supplementation or drugs known to influence vitamin B6 metabolism., Main Outcome Measure: Plasma levels of pyridoxal 5'-phosphate (PLP), pyridoxal, pyridoxine, pyridoxamine, pyridoxamine 5'-phosphate, and 4 pyridoxic acid were determined by high-performance liquid chromatography. Measured immunity markers were serum cytokines (interleukin-6, interleukin-10, and transforming growth factor-β), levels of T-lymphocyte subsets, and the proliferative ability of peripheral blood mononuclear cells., Results: Concentrations of all vitamin B6 vitamers in plasma (PLP, pyridoxal, pyridoxamine 5'-phosphate, pyridoxamine, pyridoxine, 4 pyridoxic acid) were comparable in the 2 studied groups. There were no cases of PLP deficiency in the study population, but 29% of patients had PLP concentrations more than the upper reference limit. Vitamin B6 vitamer concentrations were not influenced by gender, estimated glomerular filtration rate, and circulating phosphate concentration. There was no difference in immunity markers according to age. However, the plasma concentrations of vitamin B6 vitamers were inversely associated with levels of CD28(+) lymphocyte subsets, as well as with the proliferative response of peripheral blood mononuclear cells in both groups., Conclusions: No cases of vitamin B6 deficiency were found among kidney allograft recipients, and we report inverse links between vitamin B6 vitamer concentrations and markers of cellular immunity, suggesting that bioactive vitamin B6 concentration in kidney allograft recipients merits further investigation., (Copyright © 2013 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

Vitamin B(6) dependent seizure disorders are an important and treatable cause of childhood epilepsy. The molecular and biochemical basis for some of these disorders has only recently been elucidated and it is likely that inborn errors affecting other parts of this complex metabolic pathway are yet to be described. In man vitamin B(6) ingested from the diet exists as six different vitamers, pyridoxal (PL), pyridoxamine (PM), pyridoxine (PN), pyridoxal 5'-phosphate (PLP), pyridoxamine 5'- phosphate (PMP) and pyridoxine 5'-phosphate (PNP). Its breakdown product, 4-pyridoxic acid (PA), is excreted in urine. Here we describe an analytical LC-MS/MS method to measure all vitameric B(6) forms in plasma and have subsequently applied this methodology to investigate children with vitamin B(6) responsive seizure disorders. We show that patients with inborn errors of B(6) metabolism such as pyridox(am)ine 5'-phosphate oxidase (PNPO) deficiency have characteristic B(6) profiles which allow them to be differentiated from each other and control populations, even when on treatment with B(6). Regardless of diagnosis, patients on treatment doses of pyridoxine hydrochloride and pyridoxal phosphate have markedly elevated levels of some vitameric forms (PLP, PL and PA). Such mega doses of B(6) treatment are known to be associated with neurotoxicity. This LC-MS/MS method will be a useful tool for treatment monitoring and may help further our understanding of mechanisms of neurotoxicity in patient groups.

Aims: Various studies have shown that plasma homocysteine (HCY) serum levels are elevated in actively drinking alcohol-dependent patients a during alcohol withdrawal, while rapidly declining during abstinence. Hyperhomocysteinemia has been associated not only with blood alcohol concentration (BAC), but also with deficiency of different B-vitamins, particularly folate, pyridoxine and cobalamin., Methods: Our study included 168 inpatients (110 men, 58 women) after admission for detoxification treatment. BAC, folate, cobalamin, pyridoxine, thiamine and riboflavin were obtained on admission (Day 1). HCY was assessed on Days 1, 7 and 11., Results: HCY levels significantly declined during withdrawal. General linear models and linear regression analysis showed an influence of BAC, folate and riboflavin on the HCY levels on admission as well as on HCY changes occurring during alcohol withdrawal. No significant influence was found for thiamine, cobalamin and pyridoxine., Conclusions: These findings show that not only BAC and plasma folate levels, but also plasma levels of riboflavin influence HCY plasma levels in alcohol-dependent patients.

Background: A negative association between systemic markers of inflammation and plasma vitamin B-6 has been observed in population-based and patient cohorts; however, vitamin B-6 (pyridoxine) treatment has mostly failed to improve inflammatory indexes., Objective: We aimed to assess the effect of pyridoxine treatment on B-6 vitamer and inflammatory marker relations., Design: We measured pyridoxal 5'-phosphate (PLP), pyridoxal, 4-pyridoxic acid (PA), C-reactive protein (CRP), neopterin, and the kynurenine-to-tryptophan ratio (KTR) in plasma and the white blood cell count (WBC). A partial Spearman's correlation was used to assess associations of B-6 vitamers with inflammatory markers before and after daily treatment with 40 mg pyridoxine hydrochloride. Generalized additive models and segmented regression analysis were used for nonlinear relations., Results: A 9-60-fold increase in B-6 vitamer concentrations over baseline values was observed after 28 d of treatment with pyridoxine. PLP was negatively associated with all 4 inflammatory markers at baseline and, predominantly, with CRP and KTR at day 28. The catabolite PA was positively associated with neopterin and KTR before and after treatment. The dose-response relation between CRP and B-6 vitamers at day 28 was nonlinear, with an increased steepness of slope at CRP >7 mg/L. Finally, changes in B-6 vitamer concentrations were correlated with changes in inflammatory marker concentrations over a time span of 4 wk., Conclusions: The associations between plasma vitamin B-6 and inflammatory markers were preserved or even increased after pyridoxine treatment. The results suggest that the acute phase and activated cellular immunity are associated with increased cellular uptake and catabolism of vitamin B-6, respectively.

Introduction: The purpose of this study was to evaluate the B-6 vitamers in plasma and related symptoms in hemodialysis subjects taking high- or low-dose vitamins., Methods: A total of 24 hemodialysis (HD) subjects were divided into two groups. Twelve subjects received a high-dose vitamin supplement [50 mg pyridoxine hydrochloride (PN-HCl) /tablet] and 12 received a low-dose vitamin supplements containing (10 mg PN-HCl/tablet) for 6+ months. Plasma B-6 vitamers were analyzed using HPLC. Other data were obtained from subjects' medical records. Subjects were assessed for vitamin B-6 related symptoms. Cluster analysis was used to form symptom groups. Student t-tests and analysis of variance were used to determine differences (p < 0.05) in group means., Results: The mean ± SD plasma B-6 vitamer and 4-pyridoxic acid concentrations (nmol/L) were as follows in the 10-mg and 50-mg PN-HCl groups, respectively: pyridoxal- 5'-phosphate (PLP) 10 ± 3 and 16 ± 8 (p = 0.04); pyridoxal (PL) 50 ± 96 and 68 ± 06; pyridoxine (PN) 26 ± 50 and 191 ± 107; and 4-pyridoxic acid (4-PA) 43 ± 64 and 99 ± 361. The cluster group with a significantly higher (p = 0.04) plasma 4-PA concentration of 167 ± 697 nmol/L reported more tingling hands, tachycardia, and diarrhea., Conclusion: Plasma PLP levels and symptoms related to B-6 in HD subjects are impacted by dose of PN-HCl.

Objective: In children, vitamin B(6) (pyridoxine) deficiency has been described as a cause of seizures that are refractory to conventional antiepileptic medications. We describe the clinical presentation of 3 adults with refractory seizures (later diagnosed with vitamin B(6) deficiency) that resolved after pyridoxine treatment., Design: Case series., Setting: Tertiary care surgical intensive care unit., Patients: In the first case, a 54-year-old male with history of alcoholic cirrhosis developed new-onset seizures refractory to phenytoin and levetiracetam 8 days after liver transplantation. In the second case, a 59-year-old male with hepatitis C infection developed intracranial hemorrhage and new-onset seizures refractory to phenytoin, levetiracetam, and pentobarbital. The third patient is a 78-year-old male with a history of alcohol dependence who was admitted for an intraventricular bleed and developed new onset of refractory seizures., Interventions: Intravenous pyridoxine followed by oral pyridoxine., Measurement and Main Results: In all 3 cases, seizures persisted despite escalation of conventional antiepileptic medications but resolved within 2 days of pyridoxine supplementation. In each case, low serum pyridoxal 5'-phosphate concentrations normalized with pyroxidine administration., Conclusions: Although refractory seizures caused by vitamin B(6) deficiency are rare in adults, it should be considered in critically ill adult patients with refractory seizures.

Background: Diclectin, composed of 10 mg doxylamine succinate (DOX) and 10 mg pyridoxine hydrochloride, is the drug combination of choice for the management of nausea and vomiting during pregnancy in Canada. However, there is large variability in its onset and duration of action among women. To understand and improve its effectiveness, the variability in the pharmacokinetics of the ingredients in this doxylamine succinate/pyridoxine hydrochloride combination must be studied., Objectives: To determine the pharmacokinetics of DOX and pyridoxine after oral administration of two tablets of this drug combination in the form of Diclectin and to calculate their respective relative bioavailability by comparison with intravenous administration in another population., Methods: Eighteen nonpregnant, nonlactating, healthy females between 18 and 45 years of age were administered two tablets of Diclectin with 240 mL of water under empty stomach conditions. Blood samples were analyzed for DOX and pyridoxine along with its four active metabolites: pyridoxal, pyridoxal-5'-phosphate (PLP), pyridoxamine, and pyridoxamine-5'-phosphate using tandem mass spectrometry. For the purpose of this study, pharmacokinetic values for DOX and PLP were adjusted for body weight., Results: The mean DOX-AUC0→∞ was calculated to be 3137.22 ± 633.57 ng·hr/mL (range, 2056.59-4376.06 ng·hr/mL). The mean PLP-AUC0→∞ was calculated to be 5513.10 ± 2362.35 ng·hr/mL (range, 1572.56-10,153.77 ng·hr/mL). Based on literature values of the PLP-AUC0→∞ after intravenous administration and data from the current study, the relative bioavailability of pyridoxine in Diclectin was calculated at 100%., Conclusion: There was a 2.1-fold variability in the DOX-AUC0→∞ and 6.5-fold variability in the PLP-AUC0→∞ after oral administration of 20 mg Diclectin. Using literature values and data from the current study, we estimated the oral bioavailability of pyridoxine to be 100%. Therefore, interindividual differences in metabolism, and not in bioavailability, may be important sources of variability that need to be addressed in dosing guidelines.

Polyneuropathy related to decreased levels of Vitamin B6 are well known. In contrast, the association between elevated levels of pyridoxine and neuropathy is not well described. This study is a retrospective review of patients in our neuromuscular clinic that were found to have elevated B6 levels. Twenty-six patients were found to have elevated serum B6 levels. The mean B6 level was 68.8 ng/ml. Twenty patients (76.9%) reported daily vitamin use. Twenty-one patients (80.8%) reported only sensory complaints. The most common symptoms reported were numbness (96%), burning pain (49.9%), tingling (57.7%), balance difficulties (30.7%), and weakness (7.8%). Nine (out of 26) had an abnormal EMG/NCS. Eight patients had an abnormal quantitative sensory study. We conclude that elevated pyridoxine levels should be considered in the differential diagnosis of any sensory or sensorimotor polyneuropathy.

Objective: Homocysteine is a sulfur-containing amino acid formed during the demethylation of methionine and high levels of this amino acid is a known risk factor for both arterial and also venous thromboembolic complications. Deficiencies of cobalamin, folate, and pyridoxine may predispose subjects to hyperhomocysteinemia, a common phenomenon in inflammatory bowel disease (IBD) patients. The aim of this study was to identify the prevalence, risk factors of hyperhomocysteinemia and its correlation with prior thromboembolic events in an IBD cohort without past intestinal resections., Methods: In this prospective study, we studied the concentrations of homocysteine, cobalamin, folate, and pyridoxine in 105 consecutive patients with IBD, of whom 11 had a prior history of thromboembolic complications. Data regarding smoking habits, medication use, disease location, and severity were gathered and patients with past intestinal resections were excluded. Age-matched and sex-matched 85 healthy volunteers served as controls and multivariate regression analysis was performed to find out independent predictors of hyperhomocysteinemia., Results: The mean age (+/-SD) in the IBD cohort was 38.69+/-12.13 years, and 51% were male. The mean age in the control group was 37.61+/-10.05 years, and 52% were male. Homocysteine concentrations in patients were higher [16.35 micromol/L (range 6.82 to 48.15) vs. 9.60 micromol/L (range 4.97 to 17.39), P=0.000] and hyperhomocysteinemia had a higher prevalence in patients than in the controls (56.2% vs. 4.7%, chi2=56.179, P=0.000), thus IBD significantly increased the risk of hyperhomocysteinemia [odds ratio=25.973 (95% confidence interval: 8.861-76.128)]. Homocysteine concentrations in patients with a history of thrombosis were not higher than those without a history of thrombosis [16.29 micromol/L (range 8.45 to 34.75) vs. 16.36 micromol/L (range 6.82 to 48.15), not significant]. Hyperhomocysteinemia was found in 54.5% of patients with thrombosis and 56.4% of patients without thrombosis (not significant). On stepwise regression analysis, plasma cobalamin level, albumin concentration, erythrocyte sedimentation rate, and platelet count were found to be independent predictors of elevated homocysteine levels., Conclusions: IBD patients have a higher prevalence of hyperhomocysteinemia than do healthy controls and elevated homocysteine levels are independently associated with lower serum cobalamin, albumin levels and elevated erythrocyte sedimentation rate, and platelet count. There is no correlation between hyperhomocysteinemia and a history of prior thromboembolic events.

A rapid, simple, and highly sensitive second derivative synchronous fluorometric method has been developed for the simultaneous determination of metoclopramide (MT) and pyridoxine (PY) in a binary mixture. The method is based on measurement of the native fluorescence of these drugs at delta lambda = 80 nm in methanol. The different experimental parameters affecting the native fluorescence of the drugs were carefully studied and optimized. The fluorescence-concentration plots were rectilinear over the ranges of 0.02-0.4 and 0.1-2 microg/mL for MT and PY, respectively. The limits of detection were 0.003 and 0.007 microg/mL and the limits of quantification were 0.008 and 0.02 microg/mL for MT and PY, respectively. The proposed method was successfully applied to the determination of MT and PY in synthetic mixtures and in commercial syrup. The results were in good agreement with those obtained with a reported method. The high sensitivity attained by the proposed method allowed the determination of MT in spiked and real human plasma samples. The mean percent recoveries of MT from spiked and real human plasma (n = 3) were 93.72 +/- 3.15 and 89.72 +/- 2.19 respectively.

This report describes a case of ginkgo nut intoxication in a 2-year-old male. The patient presented with vomiting and afebrile convulsion 4 hours after eating a large number of roasted gingko nuts. There was a large volume of ginkgo nuts in his vomited matter, and on admission the concentrations of 4-O-methoxypyridoxine in his serum and urine were elevated. The patient was diagnosed as having ginkgo nut intoxication, and diazepam and pyridoxal phosphate were administered intravenously. After the treatment, his symptoms were resolved. The neurotoxicity of ginkgo nuts should be recognized by pediatricians and parents who have infants.

Plasma concentrations of B-6 vitamers and homocysteine as well as erythrocyte alanine aminotransferase activity coefficients and vitamin B-6 (dietary + supplement) intakes of apparently healthy young Latino children of immigrant parents living in rural Nebraska were determined and differences determined by gender. Thirty-five Latino children (16 males and 19 females), aged 4-8 years, were included in the study. Nutrient intake information was obtained from the children's parents utilizing two nonconsecutive 24-hour food recalls. No differences were observed by gender with regard to vitamin B-6 intakes, plasma concentrations of B-6 vitamers and homocysteine, and erythrocyte alanine aminotransferase activity coefficients. The intakes of all children met the Recommended Dietary Allowance for vitamin B-6. Plasma pyridoxal 5'-phosphate concentrations, plasma homocysteine concentrations, and erythrocyte alanine aminotransferase activity coefficients of the children were (mean +/- SD) 83.71 +/- 37.35 nmol/L, 6.81 +/- 1.63 micromol/L, and 1.08 +/- 0.06, respectively. All the Latino children of immigrant parents in this study had values indicative of adequate vitamin B-6 status.

Plasma total homocysteine (tHcy) concentrations are associated with deficits in cognitive performance in persons free from dementia. The extent to which age modifies these associations is in need of further investigation in large, community-based, prospective studies combining the following elements: 1) multiple cognitive tests; 2) statistical adjustment for the role of the vitamin cofactors folate, vitamin B6, and vitamin B12; and 3) adjustment for the presence of risk factors for cardiovascular disease and stroke. Using data collected between 1991 and 2002, the authors investigated the associations between tHcy and multiple measures of cognitive performance in 2,096 dementia- and stroke-free participants of the Framingham Offspring Study, who were stratified into three age groups (40-49 years, 50-59 years, 60-82 years), after findings of statistically significant tHcy-by-age interactions for multiple cognitive measures. Regardless of statistical adjustment for age, sex, gender, the vitamin cofactors, and cardiovascular risk factors, statistically significant inverse associations between tHcy and multiple cognitive domains were observed for individuals aged 60 or more years; no such associations were observed for participants aged less than 60 years. Early preventive interventions may be important, because the inverse association between tHcy and cognitive performance is observed beyond middle age.

Objective: To evaluate the effectiveness of a vitamin-fortified maize meal to improve the nutritional status of 1-3-year-old malnourished African children., Design: A randomised parallel intervention study was used in which 21 experimental children and their families received maize meal fortified with vitamin A, thiamine, riboflavin and pyridoxine, while 23 control children and their families received unfortified maize meal. The maize meal was provided for 12 months to replace the maize meal habitually consumed by these households., Methods: Sixty undernourished African children with height-for-age or weight-for-age below the 5th percentile of the National Center for Health Statistics' criteria and aged 1-3 years were randomly assigned to an experimental or control group. Baseline measurements included demographic, socio-economic and dietary data, as well as height, weight, haemoglobin, haematocrit, serum retinol and retinol-binding protein (RBP). Anthropometric, blood and serum variables were measured again after 12 months of intervention. Complete baseline measurements were available for 44 children and end data for only 36. Changes in these variables from baseline to end within and between groups were assessed for significance with paired t-tests, t-tests and analysis of variances using the SPSS program, controlling for expected weight gain in this age group over 12 months. Relationships between changes in variables were examined by calculating correlation coefficients., Results: The children in the experimental group had a significantly (P < or = 0.05) higher increase in body weight than control children (4.6 kg vs. 2.0 kg) and both groups had significant (P < or = 0.05) but similar increases in height. The children in the experimental group showed non-significant increases in haemoglobin and serum retinol, while the control children had a significant (P = 0.007) decrease in RBP. The change in serum retinol showed a significant correlation with baseline retinol (P = 0.014), RBP (P = 0.007) and weight (P = 0.029), as well as with changes in haemoglobin (P = 0.029)., Conclusion: Despite a small sample size, this study showed positive effects of a vitamin-fortified maize meal on weight gain and some variables of vitamin A status in 1-3-year-old African children. The study confirmed the relationship between vitamin A and iron status. The results suggest that fortification of maize meal would be an effective strategy to address micronutrient deficiencies in small children in South Africa.

Background and Aims: It is uncertain what impact increasing voluntary folate fortification may be having on the statistical power of randomized trials testing the homocysteine hypothesis of atherothrombosis. The objective of this study was to determine whether there has been a change in folate status between 1998 and 2002 in stroke patients randomized into the VITAmins TO Prevent Stroke (VITATOPS) Study at a single center in Perth, Australia, and what impact this may have had on the magnitude of the homocysteine-lowering effect achieved over time with folic acid-based multivitamin therapy., Methods: We conducted a randomized, double-blind, placebo-controlled study involving 285 patients with stroke or transient ischemic attack who were recruited between 1998 and 2002 and randomized to long-term folic acid 2.0 mg/day, pyridoxine 25 mg/day and cobalamin 0.5 mg/day (active VITATOPS medication) or placebo. Fasting plasma total homocysteine, red cell folate, serum cobalamin and serum pyridoxine levels were measured at baseline and 6 months, and the change in blood levels over 4 time quartiles and differences in levels between the two randomized treatments were examined., Results: Between 1998 and 2002, there was a significant rise in baseline mean red cell folate levels over 4 time quartiles among the entire stroke cohort (723.3, 780.1, 922.6 and 1,023.7 nmol/l in the first, second, third and fourth quartiles, respectively; p < 0.0001), but this was not associated with a spontaneous reduction in mean baseline total homocysteine levels during the same time period (12.7, 14.3, 12.1 and 12.8 micromol/l in the first, second, third and fourth quartiles, respectively; p = 0.55). The homocysteine-lowering effect of the active VITATOPS trial medication at 6 months after randomization also did not change significantly between 1998 and 2002 (difference between randomized groups: -4.1, -4.1, -3.1 and -3.6 micromol/l in the first, second, third and fourth quartiles, respectively; p = 0.56)., Conclusions: The homocysteine-lowering effect of the active VITATOPS trial medication has not attenuated significantly in the past 5 years despite increasing voluntary fortification of foods with folic acid as reflected by a progressive rise in baseline folate status. These data suggest that in the continuing absence of a program of mandatory folate fortification of food in populations served by centers participating in the VITATOPS trial, the study will remain adequately powered to test the homocysteine-lowering hypothesis for which it was designed., (Copyright (c) 2005 S. Karger AG, Basel.)

Objective: To investigate the mechanism by which exogenous oestrogen influences the homocysteine metabolism in postmenopausal women., Study Design: A randomized placebo controlled trial in which a methionine-loading test was performed, in 25 healthy postmenopausal women, before and after a 12-week oral treatment with placebo or daily 4 mg 17beta-estradiol with (HRT) or without (ERT) 10 mg dydrogesterone. Fasting and post-load homocysteine as well as Vitamins B(6), B(12) and folate were determined., Results: In both treatment groups a significant 12% decrease in fasting homocysteine was observed. This decrease was accompanied by a post-load homocysteine increase of more than 20%. Vitamin B(6) values were decreased by more than 25%., Conclusion: The hormone therapy induced lowering of fasting homocysteine and Vitamin B(6) levels and an increase in post-load homocysteine, supporting the hypothesis that homocysteine-methionine metabolism is modulated by hormone therapy in postmenopausal women.

Background: A micellar reversed-phase liquid chromatographic procedure was developed for the determination of B6 group vitamins, i.e. pyridoxine, pyridoxal and pyridoxamine, in human serum., Methods: Chromatographic conditions used were a C18 column, isocratic mode, flow-rate of 1 ml/min and UV-detection at 290 nm. Optimization of the composition of the mobile phase was performed using an interpretative strategy., Results: After modeling, the composition of the selected mobile phase was 150 mM sodium dodecyl sulphate (SDS)--2% (v/v) pentanol-dihydrogenphosphate buffer 10 mM at pH 3. In this mobile phase, serum samples were injected without pretreatment and analysis time was below 14 min. Calibrations for the three vitamins were linear, with coefficient regression better than 0.999, and intra- and inter-day precision, achieved according to ICH, offering values below 4.3% and 3.2%, respectively. The method was applied to the determination of the B6 vitamins in spiked serum samples, with recoveries around 100%, and in the pharmacokinetic determination of pyridoxine half-life in serum, which was found to be 47.5 +/- 3.2 min (n = 5). The procedure was also applied for the analysis of pyridoxine in human serum spiked with several pharmaceutical preparations that contain other drugs which do not produce any kind of interference. Finally, solutions of B6 vitamins kept at -201 degrees C are stable for up to 3 months., Conclusions: Using the method proposed here, with an SDS-pentanol mobile phase, it is possible to carry out the fast sensitive determination of B6 vitamins in serum following direct injection, without sample pretreatment.