Hideki Okubo

Protection of outer hair cells from reperfusion injury by an iron chelator and a nitric oxide synthase inhibitor in the guinea pig cochlea.

To examine whether an active process of the cochlea was injured by ischemia-reperfusion, time courses of distortion-product otoacoustic emissions (DPOAEs) were examined before, during and after 30 min cochlear ischemia using albino guinea pigs. DPOAEs decreased to the minimum level when the animals were subjected to ischemia. When the cochlea was recirculated, DPOAEs initially recovered with time until 20 min after the onset of reperfusion. However, thereafter the amplitude of DPOAEs gradually decreased toward the noise level. Administration of deferoxamine (an iron chelator) or N-nitro-L-arginine (a nitric oxide synthase inhibitor) ameliorated this decrease of DPOAEs during reperfusion and significantly increased the DPOAE amplitudes 60 min after the onset of reperfusion as compared with those in non-treated animals. These results suggest that cochlear reperfusion as well as ischemia injured the active process of the cochlea and that free radicals and nitric oxide play important roles in this injury.

Distortion-product Otoacoustic Emissions in Experimentally Induced Hydropic Ears

The postoperative changes of distortion-product otoacoustic emissions (DPOAEs) and cochlear potentials were examined using 15 albino guinea pigs in which endolymphatic hydrops was induced by obliterating the endolymphatic sac. DPOAEs (geometric mean: 4,6 and 8 kHz) were measured once before and every week after surgery. At the 2nd (n = 5), 4th (n = 5) and 12th (n = 5) postoperative weeks, endocochlear potential (EP) and compound action potential (CAP) were measured. Although the reduction in DPOAEs at 8 kHz was first detected at the 12th week, the amplitude of DPOAEs at 4 and 6 kHz was already reduced at the first week and decreased gradually thereafter. In contrast to these results, the CAP threshold was not elevated at the 2nd week and a slight increase was first detected at the 4th week. The results obtained in the present study suggest that DPOAEs are more sensitive than CAP in detecting the presence of hydrops.

Nevoid basal cell carcinoma syndrome: report of an aggressive case with ethmoid sinus invasion

Nevoid basal cell carcinoma syndrome, also referred to as Gorlin-Goltz syndrome, is a rare autosomal dominant disorder characterized by multiple basal cell carcinomas, jaw cysts, palmar or plantar pits, ectopic calcification of the falx cerebri, and various skeletal developmental abnormalities. A minority of basal cell carcinomas demonstrate aggressive behavior and involve the craniofacial bones in nevoid basal cell carcinoma syndrome. A non-familial case of nevoid basal cell carcinoma syndrome with a basal cell carcinoma of the eyelid invading to the ethmoid sinus is reported.

Thrombophlebitis of the head and neck: report of two cases.

Septic thrombophlebitis caused by head and neck infection has become a rare disorder due to the development of antibiotics. We report herein two cases of septic thrombophlebitis of the head and neck. Case 1 was a 7-year-old girl, who presented with fever, otalgia, and headache. Acute otitis media was diagnosed in another hospital. A computed tomography (CT) scan and magnetic resonance imaging (MRI) demonstrated mastoiditis with thrombophlebitis of the right lateral and sigmoid sinuses. Case 2 was a 39-year-old woman, who presented with left neck pain, fever chills and severe pharyngalacia. Peritonsillar abscess was diagnosed. A CT scan demonstrated a left internal jugular vein thrombus in addition to multiple pulmonary nodules with emboli. A diagnosis of Lemierres syndrome was made based on these findings. Both cases were successfully treated by intravenous antibiotics. A lack of awareness of these conditions and a delayed diagnosis may lead to potentially fatal consequences. A clinical suspicion of septic thrombophlebitis seems to be essential to make an accurate diagnosis during the early stage of the disease and archive a successful outcome.

Modified combination of platelet count and neutrophil “to” lymphocyte ratio as a prognostic factor in patients with advanced head and neck cancer

We evaluated the prognostic potential of the combination of platelet count and neutrophil to lymphocyte ratio (COP‐NLR) in patients with advanced head and neck cancer.

Chemotherapy for Stage IV Oral and Oropharyngeal Cancer.

Present study evaluated the effect of chemotherapy on the survival of patients with advanced oral or oropharyngeal cancer. A total of 51 patients with a stage IV squamous cell carcinoma of the oral cavity or oropharynx (40 males and 11 females), treated at the University of Tsukuba Hospital from 1988 to 2001, were included in the study. Nineteen patients were treated by full-dose irradiation and 32 patients underwent surgery after radiotherapy. Chemotherapy consisting of cisplatin (50-80mg/m2) or carboplatin (300mg/m2) followed by administration of fluorouracil (500mg/body) or peplomycin (5mg/body) for 5 days was given to 25 patients. The effect of chemotherapy on disease-free survival rate was of slight significance (0.05<p<0.1). The approach using chemotherapy for advanced oral or oropharyngeal cancer warrants further investigation.

Adenoid Cystic Carcinoma of the Sphenoid Sinus; Report of a Case

A case of adenoid cystic carcinoma of the sphenoid sinus is reported. The patient was a 38-year-old male presenting with diplopia. Computed tomography (CT) scan revealed a tumor originating from the sphenoid sinus and invading to the orbital apex and the cavernous sinus. Histological examination using specimens taken in an exploratory sphenoidectmy revealed adenoid cystic carcinoma. The patient died of disease approximately 3 years after radiotherapy at a dose of 60Gy.