“…In the last few years, creatine-kinase (CK) isoenzyme activity has been studied widely in serum and muscle of patients with progressive muscular dystrophies. This enzyme has three isoenzyme forms: MM, predominant in cardiac and skeletal muscle; BB, present in the brain; and MB, which is the hybrid form present in minor quantity in cardiac and skeletal muscle [Dawson and Fine, 19671. An increase in CK-MB in dystrophic muscle has been reported by most authors working in the field [Miyazaki et al, 1966;Goto et al, 1969;Tzvetanova, 1971;Somer et al, 1976;Tzvetanova, 1978;Yasmineh et al, 1978;Ionasescu et al, 19811, but a normal distribution of CK isoenzymes has been found by others [Kar and Pearson, 1965;Cao et al, 1968;Laudahn, 19741. The first investigation on serum activity in dystrophic patients reported the presence of only the CK-MM form [Rosalki, 1965;Miyazalu et al, 19661. More recently, with the improvement of electrophoresis and techniques of enzymatic assays, the presence of CK-MB in myopathic serum has been reported more frequently [Goto and Kabuki, 1970;Cao et al, 1971;Somer et al, 1973;Goto, 1974;Somer et al, 1976;Goedde et al, 1977;Tzvetanova, 1978;Goedde et al, 19781.…”