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苯酮尿症患者血中高浓度的苯丙氨酸(Phe)与其他大分子中性氨基酸竞争血脑屏障氨基酸转运体进入脑内,影响脑发育。通过氢磁共振波谱分析可测定脑Phe浓度,通常血/脑Phe的浓度比例约为3∶1。研究发现,脑Phe浓度较血Phe浓度与临床表型的相关性更大。个体血脑屏障对Phe的转运与脑Phe浓度相关,高表观转运米氏常数、低最大转运速率/脑内消耗率者的脑Phe浓度较低,对脑白质的损伤及智能发育的影响均较小;采用大分子中性氨基酸制剂可降低患者脑内Phe浓度,改善脑内神经递质合成,成为苯酮尿症治疗方面的又一新的探索。
High levels of phenylalanine (Phe) in the blood of patients with phenylketonuria compete with other macromolecular neutral amino acids for the blood-brain barrier amino acid transporter into the brain, affecting brain development. Brain Phe concentration can be determined by hydrogen magnetic resonance spectroscopy, usually at a blood / brain Phe concentration ratio of about 3: 1. The study found that brain Phe concentration than blood Phe concentration and clinical phenotype more relevant. Individual blood brain barrier Phe transport and brain Phe concentration-related, high apparent transport Michaelis constant, low maximum transport rate / brain depletion of brain Phe concentration were low on the white matter damage and mental development were Smaller; the use of macromolecular neutral amino acid preparations can reduce brain Phe concentration in patients with brain neurotransmitter synthesis, as phenylketonuria treatment of another new exploration.