I noticed the presence of strange sperical structures among my cells. Those are muscle cells of passage 6, freshly fixed with PFA. I am not sure if the spheres were there already before the fixation. The structures appeared to be fixed on their spots, located slightly above the cells. Very uniform in their color/texture, but the sizes range between 5-25 µm. Do you have an idea what could that be?
Update: the spheres dissapeared after additional fixation with methanol.