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ABSTRACT: Mammalian cochlear sensory epithelial cells are believed to possess minimal regenerative potential because they halt proliferation during late stage of embryogenesis and never regenerate after birth. This means that sensorineural hearing loss caused by the death of cochlear sensory epithelial cells is a permanent condition. However, stem cells were recently identified in neonatal mice following dissociation of their inner ear organs. This suggests that regenerative therapy for sensorineural hearing loss may be possible. Unfortunately, dissociation distorts the microanatomy of the inner ear, making it difficult to determine the precise location of stem cells in unaltered specimens. To develop new therapeutic approaches based on sensory epithelial cell regeneration, the location of these stem cells must be elucidated. Stem cells normally proliferate at a slow rate in adult organs. In fact, so-called label-retaining cells, or slow-cycling cells, of the brain and skin are recognized as stem cells. In this study, using the exogenous proliferation marker, 5'-bromo-2'-deoxyuridine (BrdU) in combination with the endogenous proliferation marker Ki-67, we identified tympanic border cells. These cells, which are located beneath the basilar membrane in vivo, represent slow-cycling cells of the murine cochlea. Immunohistochemically, these cells stained positive for the immature cell marker Nestin. But it will be difficult to achieve regeneration of the cochlear function because these slow-cycling cells disappear in the mature murine cochlea.
PLoS ONE 01/2012; 7(10):e48544. · 4.09 Impact Factor
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ABSTRACT: We performed ossiculoplasty under conditions preventing inflammation by adopting a planned staged operation, which is suitable for ossiculoplasty using an artificial prosthesis. We identified the presence of chorda tympani nerve as a candidate predictive factor for successful ossiculoplasty.
We aimed to summarize the outcome of ossiculoplasty and to find factors to improve the success rate.
This was a retrospective chart review of 96 patients who underwent ossiculoplasty in Kyoto University Hospital from 2001 to 2008. Patients' backgrounds, hearing outcomes, and surgical procedures were analyzed. To find predictive factors for successful ossiculoplasty, we performed logistic regression analysis.
The improvement in the mean air conduction level was 12.9 dB. The mean postoperative air-bone gap (ABG) was 25.0 dB. The ABG decreased to within 20 dB in 40.7% of the cases. As a result of univariate logistic regression analysis, primary or planned second stage surgery, closed mastoid cavity, and presence of the chorda tympani nerve were identified as favorable factors for successful ossiculoplasty.
Acta oto-laryngologica. Supplementum 11/2010;
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ABSTRACT: In cases of labyrinthine fistulae, we performed complete removal of the cholesteatoma matrix in a one-stage procedure, resulting in a satisfactory bone conduction (BC) hearing preservation rate. Preoperative evaluation of labyrinthine fistulae using high resolution computed tomography (HRCT) detected 86% of cases, and this contributed to favorable results achieved with the surgical treatment of labyrinthine fistulae. We aimed to review cases of labyrinthine fistulae to summarize their outcomes and establish standards of management.
This was a retrospective chart review of 22 patients with labyrinthine fistulae at Kyoto University Hospital from 2001 to 2009. Patient background (age and sex), location and stage of the fistulae, facial nerve status, preoperative and postoperative BC hearing levels, preoperative CT diagnosis, and surgical procedures were analyzed.
The incidence rate of the labyrinthine fistulae was 11.2%. All but one patient had labyrinthine fistula due to cholesteatoma. The fistulae were found in the lateral semicircular canal in 17 cases (77%) and in multiple organs in 4 cases (18%). The BC hearing level was preoperatively scaled out in seven cases. Preoperative HRCT scan revealed the presence of fistulae in 19 cases (86%). For all cases of cholesteatoma, the matrix was completely removed in a one-stage procedure and the fistulae were sealed using bone pate, temporal fascia, and temporal bones. Of the 15 cases with residual BC hearing ability, BC hearing was preserved in up to 12 cases. Two cases with postoperative deterioration of BC hearing had stage 4 fistulae in the cochleae.
Acta oto-laryngologica. Supplementum 11/2010;
