Schmidt-Sommerfeld E, Penn D, Kerner J, Bieber L L, Rossi T M, Lebenthal E
Department of Pediatrics, University of Chicago, IL 60637.
J Pediatr. 1989 Oct;115(4):577-82. doi: 10.1016/s0022-3476(89)80284-7.
Urinary carnitine esters were quantitated in an infant with medium-chain acylcoenzyme A dehydrogenase deficiency by means of a highly sensitive and specific radioisotopic exchange high-pressure liquid chromatography method. During fasting, the excretion of free carnitine and of acetylcarnitine, octanoylcarnitine, and hexanoylcarnitine was increased. The fractional tubular reabsorption of free carnitine was decreased, suggesting a renal leak of free carnitine. In the symptom-free, fed state, only minor amounts of free carnitine and of short-chain acylcarnitine, octanoylcarnitine, and hexanoylcarnitine were present in urine, and carnitine loss occurred in the form of "other" carnitine esters not exceeding that of control subjects. During L-carnitine therapy, the excretion of free carnitine, short-chain acylcarnitine, octanoylcarnitine, and hexanoylcarnitine, and particularly of "other" carnitine esters, was increased, suggesting a possible detoxifying effect of administered carnitine that is not confined to the elimination of octanoic and hexanoic acids. The employed method detects very low urinary concentrations of octanoylcarnitine and hexanoylcarnitine (less than 1 mumol/L) characteristic of medium-chain acyl-coenzyme A dehydrogenase deficiency and may be useful in screening for this disease, which has been associated with sudden infant death.
采用高灵敏度和特异性的放射性同位素交换高压液相色谱法，对一名患有中链酰基辅酶A脱氢酶缺乏症的婴儿的尿中肉碱酯进行了定量分析。在禁食期间，游离肉碱、乙酰肉碱、辛酰肉碱和己酰肉碱的排泄量增加。游离肉碱的肾小管重吸收分数降低，提示存在游离肉碱的肾漏。在无症状的进食状态下，尿中仅存在少量游离肉碱和短链酰基肉碱、辛酰肉碱和己酰肉碱，且肉碱损失以“其他”肉碱酯的形式出现，不超过对照组。在左旋肉碱治疗期间，游离肉碱、短链酰基肉碱、辛酰肉碱和己酰肉碱，特别是“其他”肉碱酯的排泄量增加，提示所给予的肉碱可能具有解毒作用，且不限于消除辛酸和己酸。所采用的方法可检测到尿中极低浓度的辛酰肉碱和己酰肉碱（低于1μmol/L），这是中链酰基辅酶A脱氢酶缺乏症的特征，可能有助于筛查这种与婴儿猝死有关的疾病。
