Hanisch Frank, Eger Katharina, Bork Silke, Lehnich Holger, Deschauer Marcus, Zierz Stephan
Klinik und Poliklinik für Neurologie, Martin-Luther-Universität, Halle-Wittenberg, Ernst-Grube Strasse 40, 06097 Halle/Saale, Germany.
J Neurol. 2006 Jun;253(6):735-40. doi: 10.1007/s00415-006-0101-7. Epub 2006 Apr 20.
The nonischemic forearm exercise test (NIFET) has been shown to be as effective as the classic ischemic forearm exercise test (IFET) in the diagnosis of patients with McArdle disease. Recently, the lactate increase normalized to the mechanical energy production in NIFET was suggested to have a intermediate sensitivity and satisfactory specifity for the screening of mitochondrial disorders.
NIFET at 80% maximal contraction force (MCF) was performed in normal controls (n = 41), patients with mitochondrial disorders (n = 15) and other myopathies (diseased controls, n = 20). 26 healthy volunteers also underwent IFET at 80% MCF. The ratio of lactate increase and workload was defined as specific lactate production (mmol x s/N x l).
In normal controls there was no significant different lactate increase during NIFET and IFET. The workload performed showed only a weak significant positive correlation with the lactate increase in the NIFET in normal controls (r(2) = 0.20) but not in IFET and NIFET with patients. A moderate negative correlation of specific lactate production and the absolute workload was found in all groups and in both protocols (r(2) = 0.22-0.34). The specific lactate production was highest in patients with other myopathies, intermediate in patients with mitochondrial disorders and lowest in normal controls. NIFET showed a sensitivity of only 20 % and a specifity of 95% for normal controls, but only 75 % for diseased controls.
The specific lactate production during NIFET is neither sufficiently specific nor sensitive for the diagnosis of mitochondrial disorders. Increased specific lactate production during rest-to-work transition period might be caused by increased acetyl group deficits.
非缺血性前臂运动试验（NIFET）已被证明在诊断麦克尔迪氏病患者方面与经典的缺血性前臂运动试验（IFET）一样有效。最近，有人提出在NIFET中乳酸增加量相对于机械能产生量的归一化值对线粒体疾病的筛查具有中等敏感性和令人满意的特异性。
在正常对照组（n = 41）、线粒体疾病患者（n = 15）和其他肌病患者（疾病对照组，n = 20）中进行80%最大收缩力（MCF）的NIFET。26名健康志愿者也进行了80% MCF的IFET。乳酸增加量与工作量的比值定义为特定乳酸产生量（mmol×s/N×l）。
在正常对照组中，NIFET和IFET期间乳酸增加量无显著差异。在正常对照组中，NIFET中执行的工作量与乳酸增加量仅呈微弱的显著正相关（r(2) = 0.20），但在患者的IFET和NIFET中并非如此。在所有组和两种方案中均发现特定乳酸产生量与绝对工作量呈中度负相关（r(2) = 0.22 - 0.34）。特定乳酸产生量在其他肌病患者中最高，在线粒体疾病患者中居中，在正常对照组中最低。NIFET对正常对照组的敏感性仅为20%，特异性为95%，但对疾病对照组仅为75%。
NIFET期间的特定乳酸产生量在诊断线粒体疾病方面既没有足够的特异性也没有足够的敏感性。休息到工作过渡期间特定乳酸产生量增加可能是由于乙酰基团缺乏增加所致。
