Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.1.12 (biotinidase)
 392 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The uptake of biotin and the closely related biocytin was characterized in primary cultures of calf brain microvessel endothelial (CBME) cells. Biotin uptake was found to be Na(+)-gradient dependent and independent of changes in the membrane potential. Concentration dependence revealed a single saturation mechanism with a K(m) of 47 microM and a V(max) of 101 pmol/min/mg. Inhibition studies demonstrated dependence on metabolic energy and the necessity for a free carboxyl group for transport activity. The anticonvulsants primidone and carbamazepine had no inhibitory effect. Biotin uptake into CBME cells is a secondary active, electroneutral, saturable and specific process. Biocytin which accumulates in biotinidase deficiency, a human congenital disorder, did not inhibit biotin uptake and was not transported into these cells. The presence of human serum with normal biotinidase activity significantly reduced biotin uptake by about 50%. Further, added biocytin was hydrolyzed to biotin, which accumulated intracellularly but to a lesser extent than added free biotin. Biotin uptake after addition of plasma of biotinidase-deficient patients was not different from that in the presence of normal serum. These results indicate that the absence of biotinidase activity in serum does not reduce blood-brain barrier transport of biotin.
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PMID:Biotin and biocytin uptake into cultured primary calf brain microvessel endothelial cells of the blood-brain barrier. 1070 86

In Greece, the National Newborn Screening Program was initiated in 1974 and is performed by the Institute of Child Health (ICH). However, there is a complete absence of conditions that have high rates of mortality and a relatively high prevalence listed in the Catalogue of Disorders screened by the ICH. Our laboratory has expanded the existing NBS program to include newborn screening for inborn errors of metabolism, screening for cystic fibrosis (the most common congenital disorder in the Greek population), congenital adrenal hyperplasia, and for biotinidase deficiency. From July 2007 to December 2009, 45,000 dried blood spots (DBS) were collected from infants born in Athens, Greece, and were analyzed. We present a report of our 30-month experience in the newborn screening area. The samples were tested for amino acidopathies, fatty acid oxidation disorders (FAOD), and organic acid metabolic disorders by applying flow injection analysis-electrospray ionization-tandem mass spectrometry (FIA-ESI-MS/MS); for cystic fibrosis by immunoreactive trypsinogen (IRT) measurement (time-resolved fluoroimmunoassay); for congenital adrenal hyperplasia by fluoroimmunoassay to measure the 17 hydroxy-progesterone level; and for biotinidase deficiency using a colorimetric method and a semiquantitative fluoroimmunoassay to determine biotinidase activity. Sample analysis resulted in establishing cutoff values for the respective disease markers for the first time in the Greek population. Four infants were identified with cystic fibrosis, two with congenital adrenal hyperplasia, two with phenylketonuria (PKU), one with medium-chain acyl CoA dehydrogenase deficiency (MCADD), and one with biotinidase deficiency. To the best of our knowledge, this is the first article reporting the status of expanded newborn screening in Greece.
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PMID:Expanded newborn screening in Greece: 30 months of experience. 2072 92