OBJECTIVES To determine pineal response to pyridoxine in normal men. MATERIAL AND METHODS Twelve healthy men were given orally pyridoxine (100 mg) or placebo at 1700h. Serum melatonin levels were determined every 30 minutes with simultaneous measurement of core body temperature between 1700h to 0300h. Polysomnographic sleep recordings were performed between 1800h to 2000h. RESULTS Serum mel...

1. Evidence of deficiency of, antagonism to, or abnormal dependency upon pyridoxine has been sought in four patients with primary hyperoxaluria. The urinary excretion of kynurenine, 3-hydroxykyurenineY 3-hydroxyanthranilic acid, kynurenic acid and xanthurenic acid, before and after a loading dose of L-tryptophan was used to assess pyridoxine nutrition. 2. Three of the four patients studied had ...

BACKGROUND Pyridoxine dependent epilepsy is a rare cause of seizures in childhood. The diagnosis is made on clinical criteria, that in many cases are never met. Therefore, epidemiological data on pyridoxine dependency are scarce. AIMS To study the epidemiology of pyridoxine dependent epilepsy in the Netherlands, and to determine whether the diagnosis is based on the appropriate criteria. ME...

In some patients without vitamin B6 deficiency, epilepsy can not be controlled without an extra supplement of vitamin B6. The therapeutic role of pyridoxal phosphate (PLP), the active form of vitamin B6, may not be replaced with other forms of vitamin B6 sometimes. Until now, four inborn errors of metabolism are known to affect vitamin B6 concentrations in the brain. Three of them are hyperprol...

The capacity of rat liver mitochondria to transport and metabolize B6 compounds has been studied. In B6-sufficient rats, 20% of the B6 content in liver is located in mitochondria. The ratio of pyridoxal-P to pyridoxamine-P in isolated mitochondria is increased with 2-oxoglutarate as substrate and decreased with glutamate. Isolated mitochondria contain pyridoxal-P(pyridoxamine-P) hydrolase activ...

In 1942 pyridoxine was related to protein metabolism (1). Since that time this vitamin or a derivative thereof has been described as a component of transaminase (2) and of decarboxylase (3). Pyridoxine has been claimed to be beneficial in the treatment of a variety of diseases. An attempt to produce a deficiency of this vitamin in a human subject failed to give evidence of any significant chang...

In 1942 pyridoxine was related to protein metabolism (1). Since that time this vitamin or a derivative thereof has been described as a component of transaminase (2) and of decarboxylase (3). Pyridoxine has been claimed to be beneficial in the treatment of a variety of diseases. An attempt to produce a deficiency of this vitamin in a human subject failed to give evidence of any significant chang...

y-Aminobutyric acid is present in the free form in large amounts in brain (l-3), where it is formed from glutamic acid by a L-glutamic acid decarboxylase (2, 4, 5). The enzyme requires pyridoxal phosphate as coenzyme (5), which can be synthesized in brain from adenosinetriphosphate and pyridoxal (6). This decarboxylase has a high degree of substrate and coenzyme specificity (6). The concentrati...

CONTEXT AND OBJECTIVE The coenzyme of aspartate aminotransferase is pyridoxal phosphate, generated from fresh vegetables containing pyridoxine. Vitamin B6-responsive sideroblastic anemia, myelofibrosis and Peyronies syndrome respond to high pyridoxine doses. The objective was to investigate the oral pyridoxine oral dose that would lead to maximized pyridoxal phosphate saturation of red cell asp...

In uitro, isolated choroid plexuses, the anatomical location of the system that transports vitamin I~,$ (BJ from blood into cerebrospinal fluid, and brain slices concentrated :‘H from media containing [3H]pyridoxine. Within these tissues, most of the intracellular [:‘H]pyridoxine was converted to and retained as the phosphorylated [“HIB,; vitamers. However, isolated choroid plexuses and brain s...