False Duchenne Muscular Dystrophy, Muscle Fiber Typing Of Quantitative Research

Objective:In order to explore the pattern of changes in muscular fiber types of DMD, We try to find out a correct, simple and practical technique to determine the muscular fiber type; which may be important and a significant development in DMD diagnosis.Methods:Skeletal muscular biopies of fifteen cases of DMD were investigated. After being rapidly frozen, the samples were made into frozen sections which were then subjected to preincubation myofibril ATP ase stain. Each t~iber was distinguished and determined. The images were imput to CIAS-286 EX image analysis system (made in Germanny) and the fiber traverse area, Circumference length, diameter of equivalent circle, maximal and minimal diameter were determined in each type of DMD. The skelctal muscules of five cases of normal children were used as control group. -Results: 1 The staining intensities on different muscle fibertypes can be classified in four grades: black, grey, grayish and white. 2 -?The changes of parameters of DMD were very different from those of the control group. OThe sizes of muscular fibers were uneven, the difference between hypertrophy and atrophy is significant. The variability coefficients of the maximal and minimal diamcters, traverse surface area, circumfrence and equivalent circle diameter were all in the range 332.7-908.3,exceeding the normal limit of 240. ㏕he average values of each parameter as the surface area, circumference, equivalent as the surface area, circumference, equivalent circle diameter, maximal and minimal diameters were all higher than those of the normal control group.comparison of equivalent circle diameter between different muscle fiber types showed that it was greater in fiber type I than type ~ A and was smaller in fiber type II than II A except for two cases. 〢 determination on the distribution pattern of different muscle fiber types showed a basically equal distribution of the two types, but in four cases, the amounts of Iype I fiber were roughly more those that of type II fiber.Conclusin:The siges of the muscular fibers in DMD were different through ATP ase stain and computer analysis. And the variability coefficients weie larger. This characteristion provides a reliable theoretical basis for distinguishing other type disease.