B6 vitamins

Pyridoxal phosphate, a close relative of vitamin B6, is involved in a large number of metabolic reactions. TeJl the hybridization, and predict the bond angles for each nonterminal atom. 

Riboflavin is one of the B vitamins. It is also known as vitamin B6 and is made up of carbon, hydrogen, nitrogen, and oxygen atoms. When 10.00 g of vitamin B6 is burned in oxygen, 19.88 g of C02 and 4.79 g of H20 are obtained. Another experiment shows that vitamin B6 is made up of 14.89% N. What is foe simplest formula for vitamin Be ... 

Vaporizer, cool mist, 228-229 Vinegar. See Acetic acid Vinyi chloride, 612t, 613 Visible light, 17 Vitamin B6,265 Vitamin D 265 Vitamins, 265... 

Pantothenic Acid Vitamin B1 Vitamin B2 Vitamin B6 Vitamin B12 Vitamin C... 

Vitamin B6 (Fig. 1) is the collective name for all 3-hydroxy-2-methylpyridine-derivatives with vitamin... 

In general, pyridoxamine and pyridoxin are more stable than pyridoxal. All vitamers are relatively heat-stable in acid media, but heat labile in alkaline media. All forms of vitamin B6 are destroyed by UV light in both neutral and alkaline solution. The majority of vitamin B6 in the human body is stored in the form of pyridoxal phosphate in the muscle, bound to glycogen phos-phorylase. 

Plants contain to some extent less bioavailable forms of vitamin B6, e.g., glycosylates, or biologically inactive metabolites, e.g., e-pyridoxin-lysin-complexes. In addition, the release of vitamin B6 from foods rich in fiber is assumed to be delayed. The bioavailability of vitamin B6 from animal-derived foods is therefore overall higher than from plant-derived foods. Good dietary sources of vitamin B6 include chicken, fish, pork, beans, and pulses [1]. 

Vitamin B6-coenzyme is involved in a variety of reactions, e.g., in the immune system, gluconeogenesis, erythrocyte fimction, niacin formation, nervous system, lipid metabolism, and in hormone modulation/gene expression [1, 2]. 

Vitamin B6. Figure 1 Structure of pyridoxin, pyridoxal, pyridoxamine, and the coenzymes pyridoxal-5 -phosphate and pyridoxamine-5Y-phosphate. 

Levodopa interacts with many different drugs. When levodopa is used with phenytoin, reserpine, and papaverine, there is a decrease in response to levodopa The risk of a hypertensive crisis increases when levodopa is used with the monoamine oxidase inhibitors (see Chap. 31). Foods high in pyridoxine (vitamin B6) or vitamin B6 preparations reverse the effect of levodopa However, when carbidopa is used with levodopa, pyridoxine has no effect on the action of levodopa hi fact, when levodopa and carbidopa are given together, pyridoxine may be prescribed to decrease the adverse effects associated with levodopa... 

When taking levodopa, avoid vitamin B6 (pyridox-ine) because diis vitamin may interfere with the action of levodopa (see Home Care Checklist Avoiding Certain Foods While Taking Levodopa). 

If your patient with parkinsonism is taking levodopa, he must be careful to avoid vitamin B6 (pyridoxine) because it may interfere with the therapeutic effects of the drug. Most multivitamin supplements contain vitamin B6. Therefore, be sure to instruct your patient to check with his health care provider before taking any vitamin supplements. 

There is evidence that some people are sensitive to free glutamates. These people get headaches or other symptoms if they ingest too much. This may be related to pyridoxine (vitamin B6) deficiencies, as this vitamin is necessary for glutamate metabolism. People with uncontrolled severe asthma may find that glutamates complicate or worsen their symptoms. 

Hydroxy-2-methyl-4,5-bis-[hydroxymethyl -pyridin-Hydrochlorid (Vitamin B6)8... 

Deoxy-D-r/ireo-pentulose in the Biosynthesis of Pyridoxol (Vitamin B6). 287... 

Valonia, cellulose, 326, 329-330 Vitamin B6, biosynthesis, 1-deoxy-D-threo-pentulose in, 287 Vitamin C... 

By contrast, the cytoplasmic decarboxylation of dopa to dopamine by the enzyme dopa decarboxylase is about 100 times more rapid (Am 4x 10 " M) than its synthesis and indeed it is difficult to detect endogenous dopa in the CNS. This enzyme, which requires pyridoxal phosphate (vitamin B6) as co-factor, can decarboxylate other amino acids (e.g. tryptophan and tyrosine) and in view of its low substrate specificity is known as a general L-aromatic amino-acid decarboxylase. 

LEKLEM j E (1998) Vitamin B6 functions in humans. In Clinical and physiological application of vitamin B6. Eds Eeklem, J E, Reynolds, New York Liss, 297-320. 

Lequea et al. used the activity of tyrosine apodecarboxylase to determine the concentration of the enzyme cofactor pyridoxal 5 -phosphate (vitamin B6). The inactive apoenzyme is converted to the active enzyme by pyridoxal 5 -phosphate. By keeping the cofactor the limiting reagent in the reaction by adding excess apoenzyme and substrate, the enzyme activity is a direct measure of cofactor concentration. The enzymatic reaction was followed by detecting tyramine formation by LCEC. The authors used this method to determine vitamin B6 concentrations in plasma samples. 

Brousmiche, D. W. Wan, P. Photogeneration of an o-quinone methide from pyridoxine (vitamin B6) in aqueous solution. J. Chem. Soc., Chem. Commun. 1998, 491 -92. 

Administer vitamin B6 (pyridoxine) in the setting of isoniazid toxicity... 

Elevated homocysteine concentrations have been associated with an increased risk for cardiovascular disease in both epidemiologic and clinical studies.43 Several studies have evaluated the benefit of lowering homocysteine levels with folic acid supplementation. One study reported a reduction in major cardiac events with the combination of folic acid, vitamin B12, and vitamin B6 following PCI.44 However, a more recent study found an increased risk of instent restenosis and the need for target-vessel revascularization with folate supplementation following coronary stent placement.45 The role of folate in the management of IHD is currently unclear. 

Nonpharmacologic therapy such as dietary, physical, and behavioral approaches should be considered first. Pyridoxine (vitamin B6) 10 to 25 mg three to four times daily alone or in combination with an antihistamine such as doxylamine is often used for NVP.9,11,12 This combination was previously marketed as Bendectin or Debendox but was withdrawn due to concerns over possible teratogenic effects, although the literature did not support this claim.11,12 Pyridoxine is well tolerated, but doxylamine and other antihistamines commonly cause drowsiness. For more severe NVP, promethazine, meto-clopramide, and trimethobenzamide may be effective and have not been associated with teratogenic effects.9... 

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