Oertel G
Department of Neurology, Karl-Marx-University of Leipzig, G.D.R.
J Neurol Sci. 1988 Dec;88(1-3):303-13. doi: 10.1016/0022-510x(88)90227-4.
The deltoid and lateral vastus muscles of 113 subjects aged from 1 week to 20 years who had suddenly died from accidents were studied at autopsy 8-48 h after death (mean 22 h). All muscles studied gave a positive histochemical reaction for ATPase after alkaline preincubation and for NADH-TR; the fact that the dehydrogenase was still active indicated that the material was reasonably well preserved. The muscles of children shortly after birth contained about 40% type 1 fibres; the percentage of these fibres increased to about 60% within the first 2 postnatal years and then remained constant. This indicates that the normal type 2 to type 1 transformation during development is not completed at birth. The mean diameter of the muscle fibres shortly after birth was 10-12 micron, and at age 15-20 years it was 40-60 micron. The standard deviation of the diameters within a sample never exceeded 20% of the mean value. The 5-fold increase in diameter corresponded to an increase in cross-sectional area by a factor of 25. The largest increase was observed in type 2 fibres of males (31-fold) which at age 15-20 years tended to be thicker than type 1 fibres while in females of that age type 2 fibres tended to be of smaller diameter than type 1 fibres. Before the age of 15, there was no difference between muscles from males and females, and type 1 fibres were usually thicker than type 2 fibres.
对113名年龄从1周大到20岁、因意外突然死亡的受试者的三角肌和股外侧肌在死后8 - 48小时（平均22小时）进行了尸检研究。所有研究的肌肉在碱性预温育后对ATP酶以及对NADH - TR均呈现阳性组织化学反应；脱氢酶仍具有活性这一事实表明材料保存得相当完好。出生后不久的儿童肌肉中约含40%的I型纤维；这些纤维的百分比在出生后的头两年内增加到约60%，然后保持恒定。这表明发育过程中正常的II型到I型转变在出生时并未完成。出生后不久肌肉纤维的平均直径为10 - 12微米，在15 - 20岁时为40 - 60微米。样本内直径的标准差从未超过平均值的20%。直径增加5倍相当于横截面积增加25倍。在男性的II型纤维中观察到最大的增加（31倍），在15 - 20岁时，II型纤维往往比I型纤维更粗，而在该年龄段的女性中，II型纤维的直径往往比I型纤维小。在15岁之前，男性和女性的肌肉之间没有差异，且I型纤维通常比II型纤维更粗。
