vitamin B(redirected from vitamin B B1)
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a group of water-soluble substances originally considered as one vitamin.
1. Vitamin B complex.
2. A member of the vitamin B complex, especially thiamine.
Any of several water-soluble pyridine derivatives, including pyridoxine, pyridoxal, pyridoxamine, and their phosphate esters, found in fish, poultry, potatoes, legumes, whole grains, and enriched foods, and serving as coenzymes in many biochemical processes, especially amino acid synthesis and the formation of neurotransmitters.
A complex compound containing cobalt, found especially in liver and widely used to treat pernicious anemia. Also called cobalamin, cyanocobalamin, extrinsic factor.
See folic acid.
A group of water-soluble substances originally considered as one vitamin.
Inflammation of the optic nerve, which can occur anywhere along its course from the ganglion cells in the retina to the synapse of these cell fibres in the lateral geniculate body. If the inflammation is restricted to the optic nerve head the condition is called papillitis (or intraocular optic neuritis) and if it is located in the orbital portion of the nerve it is called retrobulbar optic neuritis (or orbital optic neuritis).In papillitis the optic nerve head is hyperaemic with blurred margins and slightly oedematous. Haemorrhages and exudates may also appear. In retrobulbar optic neuritis, there are usually no visible signs in the fundus of the eye until the disease has advanced and optic atrophy may appear. However, both types are accompanied by a loss of visual acuity along with a central scotoma and impairment of colour vision. The loss of vision may occur abruptly over a few hours and recovery may be equally rapid but in some patients the loss may be slow. In retrobulbar optic neuritis, there is also pain on movement of the eyes and sometimes tenderness on palpation. The disease is usually unilateral although the second eye may become involved later. It is usually transient and full or partial recovery takes place within weeks. The primary cause of optic neuritis is multiple sclerosis but it may also be associated with severe inflammation of the retina or choroid, vitamin B deficiency, diabetes mellitus, thyroid disease, lactation, toxicity or syphilis. See Devic's disease; papilloedema; Marcus Gunn pupil; Kollner's rule; photostress test.
Group of water-solublesubstances originally considered as one vitamin.