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In this article, we describe an efficient method for testing both auditory receptor and auditory nerve function in a single recording session. Auditory receptor function is tested in response to pure tone, tone burst and click acoustic stimuli (i.e. distortion products of otoacoustic emissions, DPOAE; and auditory-evoked brainstem responses, ABR). The function of the auditory neurons and nerve is measured in response to direct electric current stimulation (i.e. electrically evoked auditory brainstem responses, eABR). All measurements were obtained from anesthetized laboratory rats during single recording sessions using hardware and software stimulation and analysis programs developed by Intelligent Hearing Systems, Miami, FL.

Small bowel ischemia is a relatively uncommon disorder requiring prompt recognition and aggressive management if significant morbidity and mortality are to be averted. The pathophysiology of the ischemic event usually will determine the management approach used. Factors to be considered include whether the ischemia is the consequence of arterial or venous occlusive disease; the cause and nature of the ischemia (ie, a consequence of arterial spasm, inflammation, complete or incomplete occlusion); whether the occlusion is the result of an embolus or thrombosis; the preexistence and degree of development of arterial collateral channels; and the existence and extent of comorbid conditions [1,2]. Established and experimental therapeutic interventions have varied in efficacy and include 1) correction of physiologic alterations predisposing to the ischemic event, 2) angiography with arterial infusion of vasodilators; 3) embolectomy or thrombectomy, and resection of necrotic bowel; 4) anticoagulation (veno-occlusive disease); and 5) selective application of thrombolytic agents. The overall success of any therapeutic intervention depends upon the early recognition and management of ischemia, as the incidence of morbidity and mortality rises after infarction occurs.

Colonic ischemia is the most common form of intestinal ischemia. It results from reduction in blood flow to the gastrointestinal tract, which, when prolonged, brings a spectrum of gross and microscopic changes in the affected intestinal wall. Clinical presentations range from asymptomatic to acute and fulminant, and outcomes from reversible to chronic and progressive or fulminant, with high morbidity and low mortality. This article presents an overview of colonic ischemia and discusses potential changes in imaging and treatment.