evaluation the skin sample showed no evidence of infection according to a veterinarian 39 s histopathological examination the condition was diagnosed as alopecia of unknown etiology the presence of an undefined u201c mononuclear cell infiltrate u201d was noted within the affected skin and without being bound by theory may indicate an autoimmune etiology for alopecia in the mouse eight mice that were developing hair loss were chosen four mice were randomly picked for the pdt treatment while the remaining four served as untreated controls pdt consisted of intravenously injecting vertporfin in a lipid based formulation visudyne u00ae novartis opthalmics duluth ga at a dosage of 1 mg kg of body weight per mouse followed by exposure to 690 nm wavelength red light at 15 j cm 2 delivered by an array of light emitting diode led panels at 1 hour post injection see simkin g et al 1997 inhibition of contact hypersensitivity with different analogs of benzoporphyrin derivative immunopharmacology 37 221 230 which is incorporated by reference as if fully set forth this was followed by two additional pdt treatments on days 7 and 14 the mice were observed and photographed on days 0 13 21 and 28 fig1 and 2 show a representative untreated control and a pdt treated mouse photographed at day 0 day 13 day 21 and day 28.