The mammalian cochlea has an outstanding ability to analyze frequencies. This function is explained by the travelling wave theory proposed by Békésy. However, the theory is based on the results of experiments using the cochlea lacking the normal configuration of a fresh cadaver. For example, a large hole was made in the wall of the Scala vestibuli to observe the basilar membrane directly. In addition, the organ of Corti and the tectorial membrane were removed. To resolve the issues associated with the previous experimental conditions, I developed a cochlea model using transparent resin and re-examined Békésy's travelling wave theory. When the window was closed, the basilar membrane did not vibrate, and the round window membrane vibrated in the reverse phase to the oval window membrane. When the window was open, the basilar membrane and the third window vibrated together, and the round window membrane did not vibrate at all. Based on these findings, I concluded that Békésy's travelling wave theory should be immediately reconsidered.

Previous data regarding association between DNA repair gene polymorphisms and the risk of hypopharyngeal squamous cell carcinomas (HPSCC) have shown controversial results. The current study aims to achieve a more accurate estimation of the association between four polymorphisms in DNA repair genes (ERCC1, XPD312, XPD751, XRCC1) and the risk of HPSCC. Genotyping was carried out by polymerase chain reaction using the restriction fragment length polymorphism (PCR-RFLP) technique. The odds ratios (ORs) and p value were calculated using statistical analyses. The distribution of DNA repair gene polymorphism in the HPSCC group did not differ from that in the control group. The XRCC1 G/A ＋ A/A genotype group developed distant metastasis of HPSCC (23.2%) less frequently in comparison to the G/G group (41%). In Japan, especially, in the Okinawa region, the mutant allele frequency of XPD312 (2.4%) and XPD751 (3.2%) gene polymorphism were lower in comparison to Europe (36%, 36%) and the United States (20%, 21%), respectively.

Kawasaki disease is an acute febrile disease commonly occurring in infants. The disease is characterized by systemic vasculitis. Kawasaki disease and retropharyngeal abscess in the early stage are difficult to differentiate because the clinical symptoms and image findings are similar. We herein report a case of Kawasaki disease with retropharyngeal abscess-like lesion. The patient was a six-year-old girl. She presented with a fever, left neck swelling and pain. Computed tomography revealed a retropharyngeal low-density lesion without ring enhancement. She had five major symptoms of Kawasaki disease, so we administered γ -globulin. As a result, her symptoms were relieved. In Kawasaki disease, the early diagnosis is important because treatment is required before coronary artery aneurysm formation. Our cases suggest that contrast-enhanced computed tomography, contrast-enhanced magnetic resonance imaging and blood test findings are useful for the early diagnosis of Kawasaki disease.

A nasal foreign body is a common finding for otolaryngologists. However, in rare cases, an unidentified nasal foreign body forms a rhinolith. We herein report the case of a rhinolith with a core of retained gauze that had been inserted approximately 60 years previously, which may be the longest record in Japan. The patient was a 75-year-old man with no symptoms. He visited the Department of Otolaryngology to have his swallowing function examined after suffering a stroke, and on a nasal endoscopic examination, we unexpectedly found a rhinolith in the inferior and common nasal meatus on the left side. It was removed under infiltration anesthesia with no major adverse events. It resembled a gray mass of fungus with fibrotic tissue like gauze. After its removal, the patient revealed that he had undergone bilateral sinus surgery as a student. It was suspected that the gauze had been inserted during this surgery. Pathologically, in addition to the fibrotic tissue and fungus, calcium deposits were observed, and a rhinolith was diagnosed. There was no additional retained gauze or rhinoliths on imaging. We should consider the possibility of an asymptomatic nasal foreign body on encountering a patient with a rhinolith, particularly in the case of elderly patients.