Dermatitis, biotin

Biotin Dermatitis depression, lassitude, somnolence Urinary biotin ... 

H Biotin Coenzyme in carboxylation reactions in gluco-neogenesis and fatty acid synthesis Impaired fat and carbohydrate metabolism, dermatitis... 

The physiologic sequelae of biotin deficiency are almost unexplored. Severe skin lesions, especially seborrheic dermatitis and Leiner s disease (Erythroderma desquamativum or exfoliative dermatitis), were increased in young infants bom of mothers on a restricted diet low in eggs, livers, and other biotin-rich foods. After biotin administration the lesions healed. There are claims that excess biotin produces a fatty liver characterized by heightened cholesterol content. Choline has no effect in the prevention of biotin-fatty livers (G2, M2). In mice with transplanted tumors, both the tumors and the blood levels of biotin are below normal (R8). More recent studies established a protection with avidin, the biotin-binding fraction of egg white, against tumor formation (K4). More data along these lines are still needed for confirmation. 

A chronically iU patient on long-term (home) parenteral nutrition develops metabolic acidosis, a grayish pallor, scaly dermatitis, and alopecia (hair loss). These symptoms subside upon addition of the B vitamin biotin to the alimentation fluid. 

When a normal diet is followed, biotin dehciency is rare. Clinical symptoms of dehciency are alopecia and cntaneons abnormalities snch as seborrhoeic dermatitis (especially in patients affected by phenylketonnria), periorihcial erythema, and fnngal infection. The main sonrces of biotin are liver, kidney, egg yolk, some vegetables snch as soybeans, nnts, spinach, mnshrooms, and lentils. In green plants and frnits, biotin occnrs in water-extractable forms, whereas in yeast and animal prodncts, it is a hrmly bonnd complex [417]. The variability on the amonnts of biotin in foods is due to both natural variation, bnt also to methodological problems. 

Biotin (vitamin B ) is widespread in foods and is also synthesized by intestinal bacteria. It is a coenzyme for the carboxylation of pyruvate, acetyl-coenzyme-A (CoA), propionyl CoA, and /1-methyl-crotonyl CoA and is involved in fatty acid formation and in energy release from carbohydrates. In humans deficiencies only occur in patients with an abnormal gut flora and manifests itself as exfoliative dermatitis and alopecia. 

Biotin deficiency is characterized by anorexia, nausea, vomiting, glossitis, depression, and dry, scaly dermatitis. Biotin deficiency occurs when avidin, a biotinbinding glycoprotein, is present. Avidin, which is found in raw egg whites, binds the biotin, making it nutritionally unavailable. 

Biotin deficiency can be triggered only experimentally, using diets rich in raw egg white. The latter contains avidin, a 70 kD protein that binds biotin in an inactive form. The deficiency leads to dermatitis and hair loss in rats. 

Angelica polymorpha Max. A. sinensis (Oliv.) Diels Dan Gui (root) Vitamin 12, vitamin E, ferulic acid, succinic acid, nicotinic acid, uracil, adenine, butylidenephalide, ligustilide, folinic acid, biotin, polysaccharide33 Treat irregular menstruation, anemia, thrombophlebitis, neuralgia, arthritis, chronic nephritis, constrictive aortitis, skin disease such as eczematous dermatitis. 

Biotin deficiency is rare but under laboratory conditions it can be induced by feeding subjects with large amounts of raw egg white which contains the protein, avidin, which has a binding site for the imidazole moiety of biotin, thus making it unavailable. Avidin is denatured by heat and, therefore, biotin binding occurs only in raw egg albumen. Symptoms of biotin deficiency include scaly dermatitis, hair loss, loss of appetite, nausea, hallucinations and depression. 

Biotin (68) is an essential growth factor for many microorganisms, but biotin deficiency is not normally found in man, except perhaps in infants. Its only therapeutic use is in the treatment of seborrhoeic dermatitis of infancy, but it has been tried for the treatment of some forms of baldness. Another heterocyclic sulfur compound, lipoic acid (69), serves as a prosthetic group in several enzymes but it has not been associated with any deficiency disease and has no therapeutic use. 

Riboflavin was found to be most responsible for the stimulation of rat growth, while vitamin B6 was needed to prevent a facial dermatitis or "rat pellagra." Pantothenic acid was especially effective in curing a chick dermatitis, while nicotinamide was required to cure human pellagra. Biotin was required for growth of yeast. 

Biotin Precursor of the coenzyme biocytin. Deficiency leads to dermatitis in humans. 

Biotin deficiency and the functional deficiency associated with lack of holo-carboxylase synthetase (Section 11.2.2.1), or biotinidase (Section 11.2.3.1), causes alopecia (hair loss) and a scaly erythematous dermatitis, especially around the body orifices. The dermatitis is similar to that seen in zinc and essential fatty acid deficiency and is commonly associated with Candida albicans infection. Histology of the skin shows an absence of sebaceous glands and atrophy of the hair follicles. The dermatitis is because of impaired metabolism of polyunsaturated fatty acids as a result of low activity of acetyl CoA carboxylase (Section 11.2.1.1). In biotin-deficient experimental animals, provision of supplements of long-chain 6 polyunsaturated fatty acids prevents the development of skin lesions (Mock et al., 1988a, 1988b Mock, 1991). 

DEFICIENCY Deficiency of biotin is rare except in people who only eat raw eggs, as egg whites contain avidin, a protein that inhibits biotin absorption. There may be a dermatitis. 

Biotin (Vitamin B7) Liver, yeast, meat, peanuts, eggs, chocolate, dairy products, grains fruits, vegetables Dermatitis, skui dryness, depression, muscle pam, nausea, anorexia (appetite loss). 

Biotin deficiency in animals results in alopecia, a. scaly dermatitis, anorexia, and eventually death. Some of the biochemical changes occurring in rats consuming a biotin-deficient diet containing raw egg white are illustrated in Figure 9.33. The animals consumed the diet for up to 30 days. The activities of three biotin-requiring enzymes were determined in the livers of rats killed at the indicated times. The en iymes measured were acetyl-CoA carboxylase ( , propionyl-Co A carboxylase (O), and pyruvate carboxylase (A). 

Biotin (vitamin H) Carboxylases Dermatitis, anorexia, depression... 

H Biotin Coenzyme in carboxyiation reactions in giuconeogenesis and fatty acid synthesis roie in reguiation of ceii cycie impaired fat and carbohydrate metaboiism dermatitis... 

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