Serum Phenylalanine (Phe) and Tyrosine (Tyr) levels in Congenital Hypothyroidism
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چکیده
منابع مشابه
Effect of tetrahydrobiopterin on Phe/Tyr ratios and variation in Phe levels in tetrahydrobiopterin responsive PKU patients.
BACKGROUND Whilst a reduction in blood phenylalanine (Phe) levels is essential in patients with PKU, a decrease in Phe/Tyrosine (Tyr) ratio and fluctuations in blood Phe levels over time have been recently associated with improved neuropsychological outcome. The aim of this study was to identify if Tetrahydrobiopterin (BH(4)) offers additional benefit based on the assumption that these 2 factor...
متن کاملMicromethods for Measuring Phenylalanine and Tyrosine in Serum.
Spectrophotofluorometricmicromethodsfor the determination of phenylalanineand tyrosine on 25 ,J. of serum are described. These methods were applied to detect phenylketonuriaamong homozygotesand heterozygotesand in the newborn population. The data presentedagreewith those previouslyreported. (1) Phenylketonurics have markedly elevated serum phenylalanineand lower serum tyrosinethan the controls....
متن کاملLiquid-chromatographic measurement of phenylalanine and tyrosine in serum.
With phenylalanine ammonia-lyase (EC 4.3.1.5) we converted phenylalanine (Phe) and tyrosine (Tyr) to transcinnamic acid and p-coumaric acid, respectively. These were separated by "high-performance" liquid chromatography and detected at 280 nm. We measured the Phe and Tyr content of human serum by adding 100 mU of the enzyme to a 20-microL serum aliquot, mixing for 2 h at 24 degrees C, then stop...
متن کاملPhenylalanine and tyrosine levels in newborn screening blood samples.
A previously described difference in newborn blood phenylalanine concentrations between those living in urban and non-urban areas in the south west of England has been confirmed and shown to be independent of the type of feed. Several factors including the place of abode, type of feed, birthweight, and the accuracy of the test have been found to affect the measured, phenylalanine concentration ...
متن کاملStructure-function studies of human aromatase by site-directed mutagenesis: kinetic properties of mutants Pro-308----Phe, Tyr-361----Phe, Tyr-361----Leu, and Phe-406----Arg.
Aromatase, a cytochrome P450, catalyzes the formation of aromatic C-18 estrogenic steroids from C-19 androgens. Four mutants of human aromatase have been expressed in Chinese hamster ovary cells using a stable expression method. The activities of these mutants were determined using [1 beta,2 beta-3H]androstenedione, [19-14C]androstenedione, and [1 beta,2 beta-3H]testosterone as substrates. The ...
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ژورنال
عنوان ژورنال: Pediatric Research
سال: 1981
ISSN: 0031-3998,1530-0447
DOI: 10.1203/00006450-198112000-00124