Positive control tissues for immunohistochemistry.

(A,B) The crypts of normal human colon were selected as control positive structures for Cx26 (A) and Cx43 (B): immunoreactivity is evident in the ephitelial cells of crypts (arrows). (C) Human myocardium was used as positive control for pS368-Cx43: immunoreactivity is localized at level of intercalated disks (arrows); immunoreactivity of myocardium for Cx43 is displayed in the box. (D) A human myenteric neuron, taken as a positive control cell for PKC, displays an intense PKCps immunoreaction. (E) A granulocyte of normal colon, chosen as positive control for RhoA, is markedly immunoreactive. (F) Mast cells (arrows), locked in the tunica muscularis of human normal colon, show a strong immunoreaction for c-Kit. In the same field an intramuscular c-Kit positive ICC is also evident (arrowhead). Scale bar: 50 µm.