Takahisa Abe

Developmental Expression of the Outer Hair Cell Motor Prestin in the Mouse

The development of motor protein activity in the lateral membrane of the mouse outer hair cell (OHC) from postnatal day 5 (P5) to P18 was investigated under whole-cell voltage clamp. Voltage-dependent, nonlinear capacitance (Cv), which represents the conformational fluctuations of the motor molecule, progressively increased during development. At P12, the onset of hearing in the mouse, Cv was about 70% of the mature level. Cv saturated at P18 when hearing shows full maturation. On the other hand, Clin, which represents the membrane area of the OHC, showed a relatively small increase with development, reaching steady state at P10. This early maturation of linear capacitance is further supported by morphological estimates of surface area during development. These results, in light of recent prestin knockout experiments and our results with quantitative polymerase chain reaction, suggest that, rather than the incorporation of new motors into the lateral membrane after P10, molecular motors mature to augment nonlinear capacitance. Thus, current estimates of motor protein density based on charge movement may be exaggerated. A corresponding indicator of motor maturation, the motor’s operating voltage midpoint, Vpkcm, tended to shift to depolarized potentials during postnatal development, although it was unstable prior to P10. However, after P14, Vpkcm reached a steady-state level near −67 mV, suggesting that intrinsic membrane tension or intracellular chloride, each of which can modulate Vpkcm, may mature at P14. These developmental data significantly alter our understanding of the cellular mechanisms that control cochlear amplification and provide a foundation for future analysis of genetic modifications of mouse auditory development.

The role of periostin in eosinophilic otitis media

Abstract Conclusion: We investigated the localization of periostin in middle ear specimens from patients with eosinophilic otitis media (EOM) and from a newly constructed animal model for EOM. Periostin-positive immunostaining was observed in the middle ear sections obtained from the EOM patients. Immunoreactivity for periostin was also seen in the animal model. These results suggest that periostin plays an important role in subepithelial fibrosis in the middle ear in EOM. Objective: The purpose of the present study was to investigate the role of periostin in the middle ear of EOM patients and an animal model. Methods: Histological and immunohistochemical analyses for periostin were carried out in the middle ear specimens of six EOM patients with/without asthma. An animal model of EOM was constructed by intraperitoneal and topical sensitization with ovalbumin (OVA). Histological and immunocytochemical analyses for periostin were also performed in this model. Results: Immunoreactivities for periostin were observed in the basement membrane and extracellular matrix of the middle ear sections obtained from all EOM patients with/without asthma. In the animal model, eosinophil infiltration and middle ear mucosa thickness were observed. Moreover, periostin-positive immunostaining was shown in the extracellular matrix of the middle ear mucosa on the side topically boosted by OVA.

Carcinoma ex pleomorphic adenoma of the parotid gland: a multi-institutional retrospective analysis in the Northern Japan Head and Neck Cancer Society

Abstract Conclusion: The 3-year progression-free survival rate of non-invasive salivary duct carcinoma (SDC) or adenocarcinoma not otherwise specified (NOS) was significantly better than that of invasive SDC or adenocarcinoma NOS in Carcinoma ex pleomorphic adenoma (CXPA). The presence of invasion is an important prognostic factor for SDC and adenocarcinoma NOS in CXPA. Objectives: CXPA is a rare parotid gland malignant tumor for which therapy is not yet standardized. The purpose of this study was to review the characteristics of CXPA patients and to analyze their outcomes in the Northern Japan Head and Neck Cancer Society. Method: The medical records of 33 patients who had been provided initial treatment in 12 institutes of northern Japan from 2002–2011 were reviewed as a multi-institutional retrospective study. Results: The 3-year overall and progression-free survival rate of all patients was 79.9% and 76.8%, respectively. Both the 3-year overall and progression-free survival rates were 87.5% for patients with non-invasive SDC or adenocarcinoma NOS. The 3-year overall and progression-free survival rates for patients with invasive SDC or adenocarcinoma NOS were 60.4% and 30.5%, respectively. The progression-free survival rates for patients with invasive SDC or adenocarcinoma NOS was significantly poor (p < 0.05).

Laryngeal neuroma in multiple endocrine neoplasia type 2B

Multiple endocrine neoplasia (MEN) type 2 syndrome is an autosomal dominant inherited disease caused by mutations of the RET proto-oncogene, and is clinically divided into three phenotypes: MEN2A, MEN2B, and familial medullary thyroid carcinoma. Although multiple mucosal neuromas are commonly observed in patients with MEN2B, there are only a few reports of laryngeal neuroma. We present here a rare case of laryngeal mucosal neuromas with MEN2B.