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Phenylalanine can be detected in brain tissue of healthy subjects by 1 H magnetic resonance spectroscopy
Author(s) -
Pietz J.,
Lutz T.,
Zwygart K.,
Hoffmann G. F.,
Ebinger F.,
Boesch C.,
Kreis R.
Publication year - 2003
Publication title -
journal of inherited metabolic disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 102
eISSN - 1573-2665
pISSN - 0141-8955
DOI - 10.1023/b:boli.0000005648.75276.71
Subject(s) - phenylalanine , phenylketonurias , kinetics , amino acid , proton magnetic resonance , magnetic resonance imaging , nuclear magnetic resonance spectroscopy , chemistry , spectroscopy , nuclear magnetic resonance , medicine , proton , pathogenesis , endocrinology , biochemistry , stereochemistry , radiology , physics , quantum mechanics
Summary: Transport of phenylalanine (Phe) and the other large neutral amino acids across the blood–brain barrier plays a crucial role in the pathogenesis of phenylketonuria (PKU). Thus, investigation of Phe transport kinetics by means of proton magnetic resonance spectroscopy ( 1 H MRS) became an important research area in the mid 1990s. As 1 H MRS measurements of brain phenylalanine are restricted to tissue concentrations above 100–150 µmol/kg wet weight, this approach was possible only in PKU patients, and comparison with healthy controls was not achieved. Using standardized single‐dose oral Phe loading in three healthy subjects, it was shown that Phe values increase steeply, peak at about 1 h post load, and decrease thereafter. In a single case study, repetitive Phe loading was then performed to achieve a plateau of high blood Phe concentrations for several hours. It was demonstrated that detection and monitoring of brain Phe concentrations is feasible by means of 1 H MRS. This approach constitutes a prerequisite for describing carrier kinetics in health.