AlprostadilErectile DysfunctionIschemiaUrethraCoitusPenisPenile ErectionSciatic NeuropathyMyocardial IschemiaDrug Administration RoutesBrain IschemiaVasodilator AgentsReperfusion InjuryDouble-Blind MethodMyocardial Reperfusion InjuryIschemic Attack, TransientReperfusionWarm IschemiaTreatment Outcome