Wataru Okita

Contribution of Nitric Oxide and Sensory Transmitters to Non-adrenergic, Non-cholinergic Innervation of Nasal Blood Vessels

The possible contribution of a non-adrenergic, non-cholinergic (NANC) vasodilator mechanism in human nasal mucosa was studied using an in vitro muscle tension measuring technique. Strips of the nasal mucosa were suspended in a Magnus tube filled with Krebs solution and aerated with 95% O2. Isometric changes in tension were detected on administration of various drugs under electric stimulation and recorded with a transducer. The relaxing reaction under electrical train pulse stimulation with pretreatment of blockers of the autonomic nerves was suppressed by nitric oxide synthase inhibitor (L-NAME) and antagonists to the receptors of sensory nerve transmitters (Spantide, hCGRP8-37). This result suggests that nitric oxide, substance P and CGRP may be mediators in the NANC inhibitory nerve system.

The use of intraoperative auditory evoked brainstem responses in the treatment of congenital ossicular anomalies

Intraoperative auditory brainstem responses (ABRs) were monitored in 3 patients undergoing middle ear surgery for congenital ossicular anomalies. It was investigated whether this technique was capable of providing useful information to the operating surgeon. After the induction of anaesthesia and intubation, standard disc electrodes were attached to the vertex (active), ipsilateral mastoid (reference), and forehead (ground). These electrodes were draped out of the surgical field. The general anaesthesia was maintained by inhalation of enflurane. Stimulus intensity was decreased from 80 dBnHL in 10 dB steps until no response was obtained. Thus latency-intensity functions for wave V of ABR were obtained. First (A) recording was performed before the incision. The tympanomeatal flap was then elevated and the bony annulus overloading the oval window was drilled out. This enabled to visualize and confirm the anomalies of the ossicles. Before reconstructing the ossicles, the tympanomeatal flap was returned to its normal position and second (B) recording was obtained. During the reconstruction, recordings (C1, C2,...) were repeated as indicated. Then it was confirmed whether the effective reconstruction was obtained for auditory function. The results suggest that latency of wave V was significantly decreased when the effective reconstruction of the ossicular chain was done. Latency-intensity function is shifted to the left of A and B functions. Intraoperative auditory assessment using ABR in the reconstructive surgery for the ossicular channel is promising in providing useful information for auditory function and in predicting postoperative hearing improvement.