PROBLEMS OF A MUSCLE DISEASE 



traces of the compound were found in the muscles of patients in whom 

 the disease was advanced. However, absolute values for the concen- 

 tration of adenosine triphosphate in dystrophic muscle have not yet 

 been obtained, because of the factors which have been previously 

 discussed, namely, difficulties inherent in correction of such values for 

 the variable content of fat, connective tissue, water, etc., of the diseased 

 muscle. The difficulties are further enhanced in this instance by the 

 extraordinary lability of adenosine triphosphate. Determination of 

 the adenosinetriphosphatase activity of myosin prepared from speci- 

 mens of diseased muscle has been more feasible. Although the myosin 

 content of biopsy specimens of muscle from dystrophic patients appears 

 to be relatively low, it was probably not lower than would be expected 

 from a consideration of the diminished concentration of contractile 

 cells in the specimens. The enzymic activity of myosin prepared 

 from the diseased muscles was approximately of the same order of 

 magnitude as that prepared from normal muscle, when tested for its 

 ability to dephosphorylate adenosine triphosphate. 



Although attention has been given thus far mainly to a con- 

 sideration of the chemical and physiological e\'ents occurring in the 

 muscles in progressive muscular dystrophy, there has been no adequate 

 evidence presented to show that the primary seat of the disease is 

 actually contained in the musculature. The possibility that the 

 muscular phenomena may be only secondary to an inherent defect 

 arising elsewhere must be kept constantly in mind, lest we become so 

 preoccupied with the organ in which the major symptoms arise that 

 we fail in our over-all search for the site of the initial disorder which 

 sets the muscular syndrome in operation. 



Local and systemic changes in metabolism observed thus far in 

 progressive muscular dystrophy have been quantitative rather than 

 qualitative. Unless, and until, genuine qualitative changes in inter- 

 mediary metabolism in this disease can be demonstrated, the syndrome 

 will continue to escape classification with the rare diseases of inborn 

 metabolism such as alkaptonuria, cystinuria, and others in which 

 such changes are apparent. 



Considered on the basis of incidence in population, progressive 

 muscular dystrophy cannot be regarded as a particularly important 

 syndrome, since happily for humanity it is a comparatively rare 

 disease. Viewed from the standpoint of what the successful solution 



