title: Immunohistochemical demonstration of S-100 protein in fibroblast-like cells of the guinea-pig heart.
abstract: The immunocytochemical localization of S-100 protein was examined in the hearts of adult guinea-pigs. In addition to Schwann cells, adipose cells and chondrocytes, fibroblast-like cells densely distributed in the cardiac skeleton, all of the four valves and tendinous chordae were immunoreactive for S-100 protein. The S-100-positive fibroblast-like cells were conspicuously rounded in shape and extended their thin, thread-like cell processes in opposite directions; the cytoplasm was restricted to perinuclear region. In these morphological features, the cells were distinctly different from ordinary fibroblasts which were immunonegative for S-100 protein. Electron microscopic observation revealed that the S-100-like immunoreactivity was distributed throughout the cytoplasmic matrix in the cell body and processes, but absent from the nuclei and cell organelles. The significance of the S-100 immunopositive fibroblast-like cells was discussed in relation to cartilaginous tissues, which have the potential to form in the region of the cardiac skeleton and valves under both normal and abnormal conditions.
mesh_terms: D000818:Animals; D001283:Atrioventricular Node / Q000166:cytology; D005347:Fibroblasts / Q000166:cytology; D006168:Guinea Pigs; D008297:Male; D008854:Microscopy, Electron; D008943:Mitral Valve / Q000166:cytology / Q000648:ultrastructure; D009206:Myocardium / Q000166:cytology* / Q000648:ultrastructure; D009418:S100 Proteins / Q000032:analysis*
chemical_list: D009418:S100 Proteins