title: Human muscle carbonic anhydrase III (CA-III). Purification, immunohistochemical localization in the human skeletal muscle and its clinical application to the neuromuscular disease.
abstract: The aim of the present work was to investigate histological localization of newly found human muscle CA-III and its diagnostic value in neuromuscular diseases. The following results were obtained. CA-III was purified as a single band from human skeletal muscle nd specific anti-CA-III antiserum was raised in the rabbits. By the direct immunoperoxidase method in human biceps muscle, CA-III was localized mainly in Type I fibers (red muscle type). A radioimmunoassay was developed for CA-III which can detect 5 ng/ml of sample. Among several human tissues, CA-III was found virtually specific to the skeletal muscles with a level of 5 mg/gm wet tissue. Normal serum CA-III level (n = 20) was 22.5 +/- 15.3 (SD) ng/ml. Among 140 cases of various diseases, elevated serum CA-III levels were found in 29 cases, all of which were only from neuromuscular diseases including 17 various muscular dystrophies, 5 polymyositis, 2 other myopathies and 5 ALS. In acute myocardial infarction with highly elevated CPK, serum CA-III remained normal. In 60 cases of various neuromuscular diseases, serum CA-III, CPK and aldolase were measured. Order of sensitivity (% frequency of elevated serum level) was CPK greater than CA-III greater than aldolase, however, CA-III was most frequently elevated in myotonic dystrophy which predominantly affects Type I fibers. In 15 ALS, raised CA-III was found in 5 cases, which were all in relatively early stages showing rapidly progressive clinical courses. This result raises a possibility to use serum CA-III for evaluation of the prognosis in ALS. It is concluded that CA-III is clinically applicable as a new diagnostic marker for muscle diseases, and probably reflects Type-I fiber abnormalities more sensitively than CPK and aldolase.
mesh_terms: D002256:Carbonic Anhydrases / Q000302:isolation & purification* / Q000378:metabolism; D003402:Creatine Kinase / Q000378:metabolism; D006651:Histocytochemistry; D006801:Humans; D007124:Immunoenzyme Techniques; D009132:Muscles / Q000201:enzymology*; D009136:Muscular Dystrophies / Q000201:enzymology; D009203:Myocardial Infarction / Q000201:enzymology; D009220:Myositis / Q000201:enzymology; D009468:Neuromuscular Diseases / Q000201:enzymology*; D011863:Radioimmunoassay
chemical_list: D003402:Creatine Kinase; D002256:Carbonic Anhydrases