Pineal response after pyridoxine test in children

Summary To characterize the pineal response to pyridoxine, plasma melatonin was measured in one hundred and twenty children 3 hours after vitamin B₆ administration. The children, aged between 1.5 and 8 years, were divided in four groups as follows: a) control day group, grouping 27 children sampled at 9:00 and at 12:00; b) control night group, grouping 29 children sampled at 21:00 and at 24:00; c) pyridoxine day group, grouping 30 children sampled at 9:00, then intravenously (i.v.) injected with 3mg/kg of pyridoxine, and sampled at 12:00; and d) pyridoxine night group, grouping 34 children sampled at 21:00, i.v. injected with 3mg/kg of pyridoxine, and sampled at 24:00. Melatonin concentration was measured by radioimmuno assay. The data obtained showed a significant increase in melatonin levels after pyridoxine administration in the pyridoxine night group (39.87 ± 8.02pg/ml basal vs 88.45 ± 9.21 pg/ml after pyridoxine, p < 0.001). The other groups did not showed significant differences in melatonin concentrations. Statistical analysis shows that the administration of pyridoxine during the nocturnal hours represents a stimulating factor to increase the pineal production of melatonin in children.     

Effect of avitaminosis B6 in mice on T-lymphocyte function in vitro

The effect of different degrees of avitaminosis B₆ in mice on the cytolytic activity of T lymphocytes, measured as the quantity of Na₂Cr⁵¹O₄ released from lysed target cells, was studied on a model of the primary immune response in a mixed lymphocyte culture in vitro. Keeping animals for 3 weeks on a diet without pyridoxine did not affect the ability of the lymphocytes to proliferate in vitro or their cytolytic activity. In animals receiving a diet without pyridoxine for 45 days the content of pyridoxal-5-phosphate in the spleen was 55% lower than in the control. Lymphocytes taken from these animals, when cultured in vitro, showed sharply weakened ability to incorporate [³H]thymidine into DNA in response to the alloantigen. The cytolytic activity of these lymphocytes also was reduced. The ability of different forms of pyridoxine to restore the functions of T lymphocytes, when disturbed by avitaminosis B₆, was studied.Laboratory of Systemic Blood Diseases, Oncologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. A. Kraevskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 8, pp. 185–188, August, 1977.     

Solubility Enhancement of Nucleosides and Structurally Related Compounds by Complex Formation

Water-soluble vitamins, amino acids, and nontoxic pharmaceutical excipients were studied as solubilizing agents for poorly water-soluble adenine (nucleic acid base), guanosine (nucleoside), and structurally related drugs (acyclovir and triamterene). The apparent solubility of the substrates (adenine, guanosine, acyclovir, or triamterene) was appreciably increased by forming complexes with the ligands (vitamins, amino acids, or other ligand). Apparent association constants (K _a ) values were measured at 25°C in pH 7 phosphate buffer using phase solubility analysis. The effect of combination ligands on substrate solubility was also studied. Additive solubility enhancement was obtained for several ligand pairs.     

Hyperoxaluria and systemic oxalosis: current therapy and future directions

Excessive urinary oxalate excretion, termed hyperoxaluria, may arise from inherited or acquired diseases. The most severe forms are caused by increased endogenous production of oxalate related to one of several inborn errors of metabolism, termed primary hyperoxaluria. Recurrent kidney stones and progressive medullary nephrocalcinosis lead to the loss of kidney function, requiring dialysis or transplantation, accompanied by systemic oxalate deposition that is termed systemic oxalosis. For most primary hyperoxalurias, accurate diagnosis leads to the use of therapies that include pyridoxine supplementation, urinary crystallisation inhibitors, hydration with enteral fluids and, in the near future, probiotic supplementation or other innovative therapies. These therapies have varying degrees of success, and none represent a cure. Organ transplantation results in reduced patient and organ survival when compared with national statistics. Exciting new approaches under investigation include the restoration of defective enzymatic activity through the use of chemical chaperones and hepatocyte cell transplantation, or recombinant gene therapy for enzyme replacement. Such approaches give hope for a future therapeutic cure for primary hyperoxaluria that includes correction of the underlying genetic defect without exposure to the life-long dangers associated with organ transplantation.     

UHILIC-MS/MS法同时测定复方三维右旋泛酸钙糖浆中5种维生素的含量

目的 建立一种超高效亲水作用色谱串联三重四极杆质谱法（UHILIC-MS/MS）,同时测定复方三维右旋泛酸钙糖浆中维生素B₁、维生素B₂、维生素B₆、烟酰胺和泛酸钙的含量。方法 采用超高效液相色谱仪,Waters ACQUITY BEHHILIC Amide色谱柱（2.1 mm×100 mm,1.7 μm）,以90%乙腈（含0.5%甲酸）-10 mmol/L甲酸铵水（含0.5%甲酸）为流动相,进行梯度洗脱,流速0.30 ml/min;在电喷雾（ESI）正离子模式下,用多反应监测（MRM）模式进行含量测定。结果 在5 min内,样品中5种维生素分别在各自考察的浓度范围内呈良好的线性关系,相关系数（r）均大于0.998 4;整体加样回收率在93.27%~100.39%之间,RSD为1.41%~4.96%;10批样品中维生素B₁、维生素B₂、维生素B₆、烟酰胺、泛酸钙的含量测定结果分别为32.40~38.91、7.002~8.462、9.677~11.17、33.64~39.58、3.276~3.771 mg/250 g。结论 本研究建立的UHILIC-MS/MS方法可快速实现对复方三维右旋泛酸钙糖浆中5种维生素类成分定性鉴定或定量检测,为复方三维右旋泛酸钙糖浆的开发利用和质量评价提供了可靠的技术检测方法。     

Supplementation with Vitamin B6 Reduces Side Effects in Cambodian Women Using Oral Contraception

Hormonal contraceptives may produce side effects that deter women from their use as a method of family planning. In nutritionally vulnerable populations these effects may be more pronounced due to micronutrient deficiencies and health status. Previous studies have been unable to resolve whether micronutrient supplementation may reduce such side effects. Aim: In a longitudinal study, 1011 women obtaining oral contraception through the public health system in rural Cambodia were allocated to either intervention or control groups, receiving either daily Vitamin B6 supplement or care as usual (without placebo). Results: The intervention participants (n = 577) reported fewer side effects in three categories: nausea/no appetite, headache, and depression compared with control group participants (n = 434). Conclusion: Women taking Vitamin B6 supplement were less likely to report side effects in a nutritionally vulnerable population. Underlying nutrition status should be considered by clinicians and reproductive health policy makers in the context of providing contraceptive services. Further investigation into micronutrient supplementation, particularly with B6, in reproductive-aged women using hormonal contraception should be conducted in other settings to determine the potential for widespread adoption.     

Simultaneous Derivative Spectrophotometric Analysis of Doxylamine Succinate, Pyridoxine Hydrochloride and Folic Acid in Combined Dosage Forms

Two UV spectrophotometric methods have been developed, based on first derivative spectrophotometry for simultaneous estimation of doxylamine succinate, pyridoxine hydrochloride, and folic acid in tablet formulations. In method I, the concentrations of these drugs were determined by using linear regression equation. Method II is also based on first derivative spectrophotometry however simultaneous equations (Vierdot''s method) were derived on derivative spectra. The first derivative amplitudes at 270.0, 332.8 and 309.2 nm were utilized for simultaneous estimation of these drugs respectively by both methods. In both the methods, linearity was obtained in the concentration range 2.5-50 μg/ml, 1-40 μg/ml and 1-30 μg/ml for doxylamine succinate, pyridoxine hydrochloride, and folic acid respectively. The developed methods show best results in terms of linearity, accuracy, precision, LOD, LOQ and ruggedness for standard laboratory mixtures of pure drugs and marketed formulations. The common excipients and additives did not interfere in their determinations.     

MAGNESIUM OXIDE-PYRIDOXINE THERAPY FOR RECURRENT UROLITHIASIS

An extensive clinical trial of four to five years duration appears to have demonstrated that daily oral supplements of magnesium oxide and pyridoxine will reduce or prevent recurrent urinary calculi in most idiopathic stone formers.