Blood biotin

Typical reference interval values for whole blood biotin by a microbiological method are 0.5 to 2.20nmol/L, mean 1.31nmol/L. Deficiency is considered likely below 0.5 nmol/L. Reference values for other metabolites and fluids have been published elsewhere. ... 

Prenatal and postnatal diagnoses can be made by enzyme assay of cultured amniocytes, fibroblasts or white blood cells. Treatment remains symptomatic. Sodium bicarbonate is necessary to correct the acidosis. Aspartic acid supplementation will improve the systemic condition but has no effect on the neurological disturbances. Biotin supplementation is of no value. 

A variety of biotin-requiring microorganisms have been used to assay biotin Saccharomyces cerevisiae (H6), Lactobacillus casei (S2), Lactobacillus arabinosus (now L. plantarum ATCC No. 8014) (W14), Micrococcus sodonensis (Al), Neurospora crassa (H10), and Rhizobium tri-folii (W7). None have been applied successfully for assaying biotin in biologic fluids. Because the flagellate Ochromoms danica had a specific and sensitive biotin requirement (A2), it was utilized as a reagent for biotin in blood, serum, urine, brain, and liver tissue (B3b). 

Blood was permitted to coagulate at room temperature. The coagulum was centrifuged off and the serum reserved for assay. Serum was assayed for biotin as described for blood. 

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. 

R8. Ritchey, M. G., Wicks, L. F., and Tatum, E. L., Biotin, choline, inositol, p-aminobenzoic acid, and vitamin B6 in transplantable mouse carcinomas and in mouse blood. J. Biol. Chem. 171, 51-59 (1947). 

Assay for human immunodeficiency virus type 1 (HIV-1) proviral DNA in peripheral blood monuclear cells can be performed by PCR followed by detection of PCR products by electrochemiluminescence-labeled oligonucleotide probe [Tris-bipyridine ruthenium (II) complex]. Since one of the PCR primers is biotin-labeled at the 5 end, facile capture of the PCR product-probe complex can be accomplished on streptavidin-conjugated magnetic particles, prior to analysis in an electrochemiluminescence analyzer (S3). 

Figure 2.9. Differential pharmacological effect elicited by vector-mediated delivery of a VIP analogue. The organ blood flow in brain and salivary gland was measured in conscious rats after i.v. administration of vehicle (saline), the brain delivery vector OX26-SA, the VIP peptide alone, or the chimeric peptide. While cerebral blood flow increased in the chimeric peptide group by 60% compared to the saline control, the increase in salivary gland blood flow seen with the peptide alone was abolished by coupling to the vector. The VIP analogue was biotinylated with a non-cleavable 14-atom spacer (biotin-XX) for coupling to the vector. Data from reference [95].

Quantitative assay of biotinidase activity including evaluation for the presence of a Km defect requires 1 ml of plasma. Serum samples can be also used. Biotin therapy does not affect the assay [ 32 ]. The activity in plasma may decrease during storage (see Pitfalls and Limitations , below). We recommend the use of ethylene-diami-netetraacetic acid (EDTA)-plasma separated from whole blood and assayed within... 

A rapid avidin/biotin ELISA has been developed for the determination of bovine somatotropin in blood and milk (150). The method uses affinity-purified polyclonal antisera raised in rabbits to immobilize bovine somatotropin from... 

In the ruminant mammary tissue, it appears that acetate and /3-hydroxybutyrate contribute almost equally as primers for fatty acid synthesis (Palmquist et al. 1969 Smith and McCarthy 1969 Luick and Kameoka 1966). In nonruminant mammary tissue there is a preference for butyryl-CoA over acetyl-CoA as a primer. This preference increases with the length of the fatty acid being synthesized (Lin and Kumar 1972 Smith and Abraham 1971). The primary source of carbons for elongation is malonyl-CoA synthesized from acetate. The acetate is derived from blood acetate or from catabolism of glucose and is activated to acetyl-CoA by the action of acetyl-CoA synthetase and then converted to malonyl-CoA via the action of acetyl-CoA carboxylase (Moore and Christie, 1978). Acetyl-CoA carboxylase requires biotin to function. While this pathway is the primary source of carbons for synthesis of fatty acids, there also appears to be a nonbiotin pathway for synthesis of fatty acids C4, C6, and C8 in ruminant mammary-tissue (Kumar et al. 1965 McCarthy and Smith 1972). This nonmalonyl pathway for short chain fatty acid synthesis may be a reversal of the /3-oxidation pathway (Lin and Kumar 1972). 

Biotin 629, 808 Biphasic system el45 Bipotentiostat 909 Bis(l-butylpentyl)adipate 60 Bis-pyrene 821 Bismuth electrodes 144 based metal sensor 136 Blood 6 electrolytes 5 gases 5 plasma 6... 

Fig. 4. Expression profile of cytokine genes in human lymphocytes detected by cDNA expression array system. RNA was extracted from human peripheral blood lymphocytes from (a) normal control subjects and (b) allergic asthmatic patients. Total RNA was reverse-transcribed and labeled with biotin, and gene expressions were detected using the Human Chemokine Nonrad-GEArray Kit (SuperArray Inc., Bethesda MD, USA). Negative control genes pUC18 DNA (1A, 2A) positive control genes /J-actin (3A, 4A) and GADPH (8B, 8C, 5A, 6A, 7A, 8A).

Streptavidin conjugated to immobilized biotin BSA, PEG Red blood cells tCP of protein-linker with PEG backfill simultaneous coating of protein linker via pFP 2003 [121]... 

To determine the type of multiple carboxylase deficiency, blood was obtained to determine the biotin holocarboxylase synthetase activity in leukocytes, and serum was sent to determine the biotinidase activity. The results of the serum biotinidase activity returned first and indicated less than 1% of mean normal serum activity, confirming that the child had profound biotinidase deficiency (less than 10% of mean normal serum biotinidase activity). Subsequently, biotin holocarboxylase synthetase activity was found to be normal. Although many states screen for biotinidase deficiency in the newborn period, this child was bom in a state where newborn screening for biotinidase deficiency is not performed. 

Children with any of the isolated carboxylase deficiencies do not improve with biotin supplementation, whereas those with multiple carboxylase deficiency do. A trial of biotin is often expedient and useful in discriminating between the isolated carboxylase deficiencies and the multiple carboxylase deficiencies. Isolated carboxylase deficiencies can be definitively confirmed by demonstrating deficient enzyme activity of one of three mitochondrial carboxylases in extracts of peripheral blood leukocytes (prior to biotin therapy) or cultured fibroblasts, whereas the activities of the other two carboxylases are normal. 

Both multiple carboxylase deficiencies are characterized by deficient activities of the three mitochondrial carboxylases in peripheral blood leukocytes prior to biotin treatment. The carboxylase activities increase to near normal or normal after treatment with pharmacological doses of biotin. Patients with biotin holocarboxylase synthetase deficiency have deficient activities of the three mitochondrial carboxylases in fibroblasts incubated in medium with low biotin concentrations (containing only the biotin contributed by fetal calf serum added to the medium for cell growth), whereas patients with biotinidase deficiency have normal carboxylase activities under these conditions. The activities of the carboxylases in biotin holocarboxylase synthetase deficiency become near normal to normal when cultured in medium supplemented with high concentrations of biotin. 

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