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Shin-Ichi Ishimoto

Publications and source records attributed to Shin-Ichi Ishimoto.

8 recordsLinked to original sources
PubMed2005

Correlation between microtia and temporal bone malformation evaluated using grading systems.

OBJECTIVE: To evaluate the relationships between temporal bone abnormalities and the severity of microtia in Japanese patients using objective grading systems. DESIGN: Retrospective case series study conducted between 1992 and 2003. SETTING: Academic, tertiary care, referral medical center. PATIENTS: One hundred forty-two ears of 109 Japanese patients (85 male and 24 female patients; mean age, 12.8 years [range, 2-36 years]) with microtia. MAIN OUTCOME MEASURES: The severity of microtia was classified according to Marx classification. Developmental abnormalities of the temporal bone were evaluated by a computed tomographic (CT) scoring system modified after the system used by Jahrsdoerfer and colleagues, using high-resolution CT scans of the temporal bone. Correlations between the scores obtained from these 2 grading systems were evaluated using a nonparametric statistical method. RESULTS: Male preponderance and incidence of bilateral cases of approximately 30% were observed in our Japanese patients with microtia. There was no significant difference in the severity of microtia between unilateral and bilateral cases. The mean +/- SEM total points in the CT scoring system (full marks, 10) was 7.9 +/- 0.4 for grade I microtia, 6.6 +/- 0.6 for grade II, and 6.4 +/- 0.3 for grade III; the total points correlated inversely with the microtia grade. Development of the auricle correlated significantly with aeration in the middle ear spaces but not with ossicular development or formation of the oval/round windows. Proportion of acceptable surgical candidates according to the CT scoring system (>5 points) was 79% for grade I microtia, 52% for grade II microtia, and 65% for grade III microtia. CONCLUSION: The principle "the better developed the auricle, the better developed middle ear" was confirmed in Japanese patients with microtia; however, even with grade II/III microtia, more than half of the patients were considered suitable for atresia surgery.

Abnormalities, Multiple↗
PubMed2004

The role of the external auditory canal in the development of the malleal manubrium in humans.

OBJECTIVE: To determine if the external auditory canal (EAC) plays a role in the induction and proper positioning of the malleal manubrium in humans. STUDY DESIGN: Retrospective study between 1994 and 2002. SETTING: Academic, tertiary care referral medical center. Patients Fifty-five ears of 50 patients with congenital atresia (n = 47) or stenosis (n = 8) of the EAC, for which meatoplasty was performed at the University hospital between 1994 and 2002. MAIN OUTCOME MEASURES: The presence of the manubrium was examined during surgery, and the corre-lation between the presence of the manubrium and the grade of the microtia was evaluated. RESULTS: The manubrium was identified in all ears with EAC stenosis, whereas it was absent in all ears with EAC atresia. No correlation was observed between manubrium formation and auricular deformity. CONCLUSIONS: Our results demonstrated a close relationship between the formation of the EAC and that of the malleal manubrium in humans. This is consistent with the recent findings in knockout mice. This information is useful for surgical intervention in cases of congenital EAC anomalies.

Adolescent↗
PubMed2003

Math1 gene transfer generates new cochlear hair cells in mature guinea pigs in vivo.

Hair cell loss in the mammalian cochlea is irreversible and results in permanent hearing loss. Math1, the basic helix-loop-helix transcription factor homolog of the Drosophila atonal gene, is a positive regulator of hair cell differentiation during cochlear development. Developing hair cells express Math1, and nonsensory cells do not. We set out to determine the outcome of overexpression of Math1 in nonsensory cells of the cochlea on the phenotype of these cells. We demonstrate that in vivo inoculation of adenovirus with the Math1 gene insert into the endolymph of the mature guinea pig cochlea results in Math1 overexpression in nonsensory cochlear cells, as evident from the presence of Math1 protein in supporting cells of the organ of Corti and in adjacent nonsensory epithelial cells. Math1 overexpression leads to the appearance of immature hair cells in the organ of Corti and new hair cells adjacent to the organ of Corti in the interdental cell, inner sulcus, and Hensen cell regions. Axons are extended from the bundle of auditory nerve toward some of the new hair cells, suggesting that the new cells attract auditory neurons. We conclude that nonsensory cells in the mature cochlea retain the competence to generate new hair cells after overexpression of Math1 in vivo and that Math1 is necessary and sufficient to direct hair cell differentiation in these mature nonsensory cells.

Adenoviridae↗
PubMed2002

Direct application of keratinocyte growth factor, basic fibroblast growth factor and transforming growth factor-alpha during healing of tympanic membrane perforation in glucocorticoid-treated rats.

Peptide growth factors and cytokines modulate both normal and impaired wound healing. Topical application of growth factors in the form of ear drops may counteract impairment of wound healing in the tympanic membrane (TM). We applied keratinocyte growth factor (KGF), transforming growth factor (TGF)-alpha or basic fibroblast growth factor (bFGF) to the perforated TMs of rats in which healing impairment had been caused by systemic administration of a glucocorticoid. Histologic studies of the injured TM, including anti-5-bromo-2'-deoxyuridine immunohistochemistry, were performed on the third day after wounding. In the control ear, epidermal migration was markedly inhibited by glucocorticoid treatment and no hyperplasia was observed in any layer at the perforation edge. TMs treated with KGF showed marked hyperplasia in the epithelial layer at the perforation edge. In the bFGF- and TGF-alpha-treated groups, hyperplasia was observed in the epithelial and intermediate layers of the TM near the malleus handle and annulus, while no hyperplasia was seen in any layer at the perforation edge. Only KGF, therefore, improved epidermal migration in the TM, while all the growth factors tested induced hyperplasia in the TM.

Animals↗
PubMed2002

Total middle ear reconstructive surgery for the radicalized ear.

OBJECTIVE: To evaluate the efficacy of total middle ear reconstructive surgery (TMRS) for patients with open cavity problems. STUDY DESIGN: Retrospective study of patients treated between 1994 and 1997. SETTING: Tertiary care, referral medical center. PATIENTS: Fifty-nine consecutive patients (62 ears) with open cavity problems (draining ears) who underwent TMRS. MAIN OUTCOME MEASURES: Postoperative states of the ears and complications were evaluated in two groups, with and without persistent purulent otorrhea at the time of surgery. RESULTS: In the noninfected group, ears without otorrhea were maintained in 12 (100%) of 12 ears in the short term and 10 (83%) of 12 ears in the long term. In the infected group, the proportions were 40 (80%) of 50 ears and 35 (73%) of 48 ears, for the short and long terms, respectively. Hollowing and/or retraction of the reconstructed canal wall was observed in 1 (8%) of 12 ears of the noninfected group and in 15 (31%) of 48 ears of the infected group after long-term follow-up. Postoperative complications were encountered in 9 ears (14.5%) in the infected group only. CONCLUSIONS: Total middle ear reconstructive surgery is considered useful for the management of persistent discharge from radicalized cavities. It was found important to minimize infection at the time of surgery to achieve satisfactory results.

Adult↗
PubMed2002

Vocal cord paralysis after surgery for thoracic aortic aneurysm.

OBJECTIVE: To determine the incidence, etiology, prognosis, and treatment of vocal cord paralysis (VCP) after surgery for thoracic aortic aneurysm (TAA). STUDY DESIGN: Retrospective study performed between 1989 and 1995. SETTING: Academic, tertiary care, referral medical center. PATIENTS: Seventy-one TAA patients underwent surgery at the Kameda Medical Center between 1989 and 1995. RESULTS: Sixty-two of 71 patients were examined postoperatively for voice quality. Twenty patients (32%) had hoarseness develop caused by VCP, as confirmed by laryngoscopy. The left recurrent laryngeal nerve had been sacrificed in 1 patient during surgery, but it was preserved in the remaining 19 patients. Unilateral left VCP was noted in 19 patients, and bilateral VCP occurred in 1 patient. The incidence of VCP was higher in those patients who underwent surgery for type I aneurysms (9 of 14 patients, 64%). In 16 of the 19 patients (84%) who received follow-up for > 6 months, vocal cord movement did not return to normal. Surgery to improve voice quality, arytenoid adduction in five patients and intracordal injection in two patients, was performed with success. CONCLUSIONS: Our results indicate that surgery for TAA is associated with a relatively high incidence of VCP. VCP occurred despite preservation of the recurrent laryngeal nerve, and the paralysis did not show a spontaneous recovery even 6 months after surgery.

Adult↗