Higher levels of total serum creatine kinase activity have been reported in black compared with white North Americans of the same sex. In a study among South Africans, we found such an interracial difference was notable only for males. The difference was heightened by physical activity. This study affirms the importance of sampling the indigenous population when developing a reference range for...

Members of three unrelated families with the mild Becker type of muscular dystrophy were subjected to lymphocyte capping tests and measurements of serum creatine kinase activity. Both tests correctly identified all nine affected males, but only the capping test was abnormal in seven of eight obligate carriers. The number of capped cells in carriers and affected persons with the Becker-type dyst...

Twenty patients’ serums have been analyzed by both the Sax-Moore (1) and ConnAnido (2) creatine kinase methods. No significant difference in enzyme activity was found. In our hands, the Conn-Anido procedure, as originally described, gave variable results and high background fluorescence. The presence of high alkaline or acid phosphataseactivities in specimensanalyzed by the Sax-Moore procedure ...

Direct assay of creatine kinase by the method of Siegel and Cohen with the Technicon “SMA 12/60” is compared with two indirect coupled-enzyme assay methods. The direct method was linear to greater than 2000 U/liter, whereas the indirect methods were linear to 250 and 1500 U/liter, with use of serial dilutions of a creatine kinase preparation. Increasing the activity of the auxiliary enzymes, he...

Spectrophotometry of CK-B subunit activity based on immunoinhibition is rapid and convenient. However, the low sensitivity limits clinical applications to serum samples with CK-B activities considerably above normal. A sensitive, but not optimized, bioluminescent assay of CK-B, also based on immunoinhibition, has been described. We improved this method by the use of an ADP concentration saturat...