PROBLEMS OF A MUSCLE DISEASE 



sharp lines can be drawn between many of the primary syndromes of 

 muscle, and that some unknown defect in metabolism is responsible 

 for the biological continuity and sequence of phenomena common to 

 these clinical disorders. 



The problem of the secondai'y affections of muscle resolves 

 itself into a fundamental one having to do with the complex relation- 

 ship between the integrity of the innervation of muscle and the main- 

 tenance of an optimum state of nutrition of muscle cells. This so- 

 called "trophic efTect" which cells of the nervous system appear to 

 exert on the metabolism of the contractile cells of muscle is nearly as 

 complex as the problem of muscle metabolism itself, and cannot be 

 sharply divorced from a total consideration of other diseases afTecting 

 the muscular system in which no neurological component is recog- 

 nized. 



Although the study of the muscle disorders has not kept pace 

 with advances in the field of biochemistry and physiology of muscle, 

 it has only recently received impetus from several new and important 

 sources of information. The discovery of a disease of dietary origin 

 in animals which resembles progressive muscular dystrophy, but 

 which, unlike the disease in man, is cured with vitamin E, is influencing 

 the study of human affections of muscle. The clinical observation 

 that prostigmine relieves to a variable extent th^ symptoms of myas- 

 thenia gravis has accelerated fundamental studies on the metabolism 

 of acetylcholine in this disease. The discovery of an aberration in 

 potassium metabolism in periodic muscular paralysis had led to some 

 success in a search for efTective therapy for this disorder, and to the 

 institution of basic studies on the relation of periodic paralysis to other 

 disturbances in muscle function associated with changes in the con- 

 centration of potassium. The presence of a disease in goats, indis- 

 tinguishable symptomatically from congenital myotonia in man, has 

 greatly facilitated studies on the group of myotonic maladies. In the 

 near future, therefore, increasing knowledge of the physiology of 

 muscle, particularly that pertaining to the physiology and chemistry 

 of contraction, transmission of excitation from nerve to muscle, and 

 the mode of action of specific pharmacological agents on the myoneural 

 junction, should provide many new and effective means for an attack 

 on the problem of the muscle diseases as a whole. 



No one syndrome among the diseases of muscle has provided 



