Sinkeler S P, Daanen H A, Wevers R A, Oei T L, Joosten E M, Binkhorst R A
Department of Neurology, University of Nijmegen, The Netherlands.
Muscle Nerve. 1985 Jul-Aug;8(6):523-7. doi: 10.1002/mus.880080608.
Subjects with myopathies associated with certain enzyme defects often show abnormal concentrations of lactate (LA) and ammonia (NH3) in blood after ischemic exercise. Myoadenylate deaminase (MAD) deficient patients produce only small amounts of NH3, whereas LA rises to normal levels. On the other hand, patients with certain enzyme deficiencies in the glyco(geno)lytic pathway show the opposite. However, the concentrations in blood are dependent on the exercise performed. Standardization of tests for screening purposes, therefore, is necessary. For ischemic contractions, experiments were performed to find the optimal combination for force and frequency, using the highest LA and NH3 concentrations in blood as criteria. Eleven healthy subjects performed ischemic isometric contractions with a handgrip dynamometer at frequencies of 30 and 50/min(-1) and force levels of 50%, 65%, and 80% of maximal voluntary contraction (MVC). A combination of 30/min(-1) and 80% MVC was found to give the best results.
患有与某些酶缺陷相关的肌病的受试者在缺血运动后，血液中乳酸（LA）和氨（NH3）的浓度常常显示异常。肌腺苷酸脱氨酶（MAD）缺乏的患者仅产生少量的NH3，而LA会升至正常水平。另一方面，糖（原）酵解途径中某些酶缺乏的患者则表现出相反的情况。然而，血液中的浓度取决于所进行的运动。因此，为了筛查目的对测试进行标准化是必要的。对于缺血性收缩，进行了实验以找到力和频率的最佳组合，以血液中最高的LA和NH3浓度作为标准。11名健康受试者使用握力计以30和50次/分钟（-1）的频率以及最大自主收缩（MVC）的50%、65%和80%的力水平进行缺血性等长收缩。发现30次/分钟（-1）和80%MVC的组合能产生最佳结果。
