caa a22 4500 475785789 CHVBK 20180406123657.0 cr unu---uuuuu 170329e20000901xx s 000 0 eng 10.1007/PL00014374 doi (NATIONALLICENCE)springer-10.1007/PL00014374 In vivo proton magnetic resonance spectroscopy in phenylketonuria [Elektronische Daten] [Harald E. Möller, Kurt Ullrich, Josef Weglage] In vivo nuclear magnetic resonance spectroscopy permits the non-invasive examination of metabolic characteristics of the human brain in a clinical environment. Methods to detect elevated phenylalanine (Phe) in patients with phenylketonuria (PKU) using difference spectroscopy and to estimate absolute brain Phe concentrations, [Phe]brain, have been developed. In patients with classical PKU, [Phe]brain typically varied between 0.14 and 0.78 mmol/l depending upon actual blood Phe concentrations, [Phe]blood, between 0.47 and 2.30 mmol/l. Dynamic investigations can be used to extract information about Phe transport at the human blood-brain barrier, which may be described by a symmetric Michaelis-Menten model. Carrier saturation and competitive inhibition of the influx of other large neutral amino acids can be expected at blood levels usually found in PKU patients. In single cases of untreated, normal intelligent patients, abnormally low [Phe]brain ≤ 0.15 mmol/l were observed despite high stationary Phe levels ([Phe]blood=1.15 ± 0.10 mmol/l). Conclusion Significant variations in phenylalanine transport parameters in untreated, normal intelligent patients indicated that blood-brain barrier transport or intracerebral phenylalanine consumption are causative factors for the individual vulnerability to phenylketonuria. Springer-Verlag Berlin Heidelberg, 2000 Key words Blood-brain barrier nationallicence Nuclear magnetic resonance spectroscopy nationallicence Phenylalanine transport nationallicence Phenylalanine turnover nationallicence Phenylketonuria nationallicence AbbreviationsBBB blood-brain barrier nationallicence Cr creatine nationallicence NMR nuclear magnetic resonance nationallicence Phe phenylalanine nationallicence [Phe]blood blood Phe concentration nationallicence [Phe]brain intracerebral Phe concentration nationallicence PKU phenylketonuria nationallicence PRESS point resolved spectroscopy nationallicence STEAM stimulated echo acquisition mode nationallicence T2 app apparent spin-spin relaxation time nationallicence TE echo time nationallicence VOI volume-of-interest nationallicence Möller Harald E. Institute for Physical Chemistry, University of Münster, Schloßplatz 4/7, 48149 Münster, Germany e-mail: moeller@uni-muenster.de Tel.: +49-251-8356140; Fax: +49-251-8347312, DE aut Ullrich Kurt Department of Paediatrics, University Hospital Eppendorf, Hamburg, Germany, DE aut Weglage Josef Department of Paediatrics, University f Münster, Münster, Germany, DE aut https://doi.org/10.1007/PL00014374 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/PL00014374 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Möller Harald E. Institute for Physical Chemistry, University of Münster, Schloßplatz 4/7, 48149 Münster, Germany e-mail: moeller@uni-muenster.de Tel.: +49-251-8356140; Fax: +49-251-8347312, DE aut NATIONALLICENCE 700 1- Ullrich Kurt Department of Paediatrics, University Hospital Eppendorf, Hamburg, Germany, DE aut NATIONALLICENCE 700 1- Weglage Josef Department of Paediatrics, University f Münster, Münster, Germany, DE aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer