Kouji Yajin

Localization of nitric oxide synthase in human nasal mucosa with nasal allergy.

Nitric oxide (NO) plays an important role in the regulation of upper respiratory function. In the nasal cavity, the concentration of NO in the air in patients with untreated allergic rhinitis is higher than that in normal individuals. NO is produced by the action of NO synthase (NOS) using L-arginine as a substrate. To investigate the expression of NOS in human nasal mucosa, histochemical staining for NADPH diaphorase and immunohistochemical staining for NOS isoforms were carried out in nasal inferior turbinate mucosa from patients with nasal allergy. Those without nasal allergy served as controls. NADPH diaphorase histochemical study revealed that NOS was expressed in the nasal epithelium, submucosal glands, nerve fibres and the endothelium in specimens of both allergic and control groups. Immunoreactivity to endothelial NOS (eNOS) was localized to epithelial and endothelial cells in both allergic and control groups. In some specimens in both groups, nerve fibres around submucosal glands stained positively for eNOS. Immunoreactivity to eNOS, however, was slightly stronger in the epithelia of the allergic group than in those of the controls. Immunoreactivity to inducible NOS (iNOS) was localized to epithelial cells, endothelial cells, nasal glands and inflammatory cells. The staining of epithelial cells and inflammatory cells was more marked in the allergic group than the controls. These findings may suggest that the greater amounts of NO in the nasal air of patients with allergic rhinitis are mainly induced by iNOS activity.

Recurrent lower gingival squamous cell carcinoma spreading along the pathway of the inferior alveolar nerve

Computed tomography images showed recurrent lower gingival squamous cell carcinoma spreading from the mandibular foramen to the middle cranial fossa. This extensive tumor spread followed exactly the same anatomic pathway as the inferior alveolar nerve. Histopathologic examination revealed squamous cell carcinoma. Tumor spread was thought to be caused by perineural invasion. This case demonstrates computed tomography features of perineural tumor spread along the inferior alveolar nerve.

Effect of Streptomycin Intoxication on Vestibular Nerve Regeneration and Posture Recovery

The action of streptomycin sulfate (SM) on the regenerative process of the vestibular nerve and posture recovery was studied, using bull frogs. The vestibular nerve was sectioned in various conditions with intact endorgan or with SM intoxication. When the nerve was sectioned with the hair cells left intact, the nerve regenerated well and body balance recovered to normal. However, when neural regeneration was blocked, recovery was incomplete. SM intoxication resulted in various degrees of hair cell damage. Degree of posture recovery correlated well with the number of hair cells. When the nerve was sectioned after damaging the hair cell, the nerve failed to regenerate and posture recovery was incomplete. These results suggest that the degree of posture recovery depends on hair cell function and neural regeneration. Furthermore, neural regeneration is strongly influenced by hair cell function.

Modified Canalith Repositioning Procedure for Benign Paroxysmal Positional Vertigo.

The majority of benign paroxysmal positional vertigo (BPPV) cases with posterior canal lesion can be easily cured by the canalith repositioning procedure (CRP). BPPV with lateral canal lesions can also be cured by a modified CRP specifically designed by the authors. There are some cases which present with a combination of pure-torsional nystagmus and direction-changing geotropic nystagmus. This type of BPPV could involve both posterior and lateral semicircular canals. Twelve cases of such a combined type of BPPV were treated by applying the CRP for each canal. Complete remission was obtained in 5 cases, and a substantial decrease in the nystagmus was observed in the other 7 cases. The CRP should be applied to cases of BPPV with combined lesions as the first choice of treatment.