Intercalated discs are positive ( can be further diluted).

Upper image: ab2910

Lower image: ab16051

Upper image: ab16051

Lower image ab2910

Near serial sections.

What are these cell clusters that show membraneous beta Catenin and cytoplasmic Caveolin positivity?

Upper image immunostained for Caveolin shows very strong cytoplasmic  positivity in a small group of cells. Myofibres show a moderate membraneous positivity.

Immunostaining with anti beta Catenin ( lower image) shows strong intercalated disc positivity in myofibres but, membraneous positivity in the cells that exhibit strong cytoplasmic Caveolin positivity.

What cells are these?

Arrowheads: red indicater strong membrane positivity of epithelial basal cells; green indicates strong positivity at the interface between myoblasts beginning  to merge, subsequently  forming  myotubes.

Developing seminiferous tubules

Medulla: T/S