Figure 2 Immunohistochemical analyses of desmin, ubiquitin and desmin mRNA in the heart of control and in patients with idiopathic dilated cardiomyopathy (IDCM). Immunohistostainings with desmin antibodies revealed: normal, gentle staining of desmin at Z-lines and intercalated disks (A, control); normal, gentle staining of desmin at Z-lines and intercalated disks, giving a regular cross-section pattern (B, type I); increased, intensive staining of desmin at Z-lines and intercalated disks, giving regular cross-striation pattern (C, type IIA); increased, intensive staining of desmin with an irregular cross-striation pattern and/or with the presence of aggregates in perinuclear areas and, occasionally, in intermyofibrillar spaces (D, type IIB); decreased or lack of desmin staining (E, type III). Immunohistostainings with ubiquitin antibodies revealed: gentle, evenly scattered expression of ubiquitin in the cytoplasm of cardiomyocytes (F, control); gentle, evenly scattered expression of ubiquitin in the cytoplasm of cardiomyocytes (G, type A); increased, evenly scattered expression of ubiquitin in the cytoplasm of cardiomyocytes (H, type B); increased, unevenly scattered expression of ubiquitin in the cytoplasm of cardiomyocytes and its increased, evenly scattered expression in the nucleus (I, type C); weak/lack of expression of ubiquitin (J, type D) evaluated using light microscopy. Hybridization signal observed in tissue sections (K, L, M, N, O). Nuclei in each tissue section were stained with DAPI (K, L, M, N, O). Overlay demonstrated the localization of desmin (green colour) and desmin mRNA (red colour). Desmin mRNA proteins were localized in the nucleus of cardiomyocytes and very gently in the cytoplasm (K, control). In patients with DCM, desmin mRNA proteins were localized in the cytoplasm and in the nucleus of cardiomyocytes. Desmin mRNA showed: weak, but even expression in both the nucleus and cytoplasm (L, type 1); intensive expression, which was more pronounced in the nucleus than in the cytoplasm (M, type 2); intensive expression in the cytoplasm, and similar or weaker expression in the nucleus (N, type 3); absent desmin mRNA in the nucleus and very weak distribution in the cytoplasm (O, type 4).