PMC5140878_01
Histological examination of biopsied skeletal muscle samples. Immunohistochemistry procedures were performed with an established method using formalin-fixed, paraffin-embedded sections. The following antibodies were used and diluted as shown: Cardiac troponin T (cTnT), Cardiac Isoform Ab-1 (Lab Vision Corp., Fremont, USA, Cat. no. # MS-295-P1; 1: 100). To detect bound antibodies, slides were incubated with antimouse-labeled polymer peroxidase and developed with the HRP/ DAB Detection System [Horseradish peroxidase/Diaminobenzidine (Dako)] for 2 min. Skeletal myocytes in noncaseating granulomas stained positive for cTnT (arrows) (A, B), as well as a skeletal myocyte surrounded by inflammatory cells (C, D).
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Therefore, a biopsy of her bicep was performed and revealed noncaseating epithelioid granuloma (Fig. 1A), suggesting sarcoidosis. Immunohistochemical staining for cTnT was positive in the degenerated skeletal muscle (Fig. 1B and D).
Time course of creatine kinase (CK) and cardiac troponin T (cTnT) in response to steroid therapy.
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Her muscular symptoms subsequently improved, and the CK (131 IU/L) and cTnT (0.026 ng/mL; Roche) levels also normalized (Fig. 2).