Resume of Myung Whan Suh, 1990-05

Naval Postgraduate School Faculty Resum

Decreased Immunoreactivities of the Chloride Transporters, KCC2 and NKCC1, in the Lateral Superior Olive Neurons of Kanamycin-treated Rats

ObjectivesFrom our previous study about the weak expressions of potassium-chloride (KCC2) and sodium-potassium-2 chloride (NKCC1) co-transporters in the lateral superior olive (LSO) in circling mice, we hypothesized that partially damaged cochlea of circling mice might be a cause of the weak expressions of KCC2 or NKCC1. To test this possibility, we reproduced the altered expressions of KCC2 and NKCC1 in the LSO of rats, whose cochleae were partially destroyed with kanamycin.MethodsRat pups were treated with kanamycin from postnatal (P)3 to P8 (700 mg/kg, subcutaneous injection, twice a day) and sacrificed for immunohistochemical analysis, scanning electron microscope (SEM) and auditory brain stem response.ResultsThe SEM study revealed partially missing hair cells in P9 rats treated with kanamycin, and the hearing threshold was elevated to 63.8±2.5 dB SPL (4 ears) at P16. Both KCC2 and NKCC1 immunoreactivities were more prominent in control rats on P16. On 9 paired slices, the mean densities of NKCC1 immunoreactivities were 118.0±1.0 (control) and 112.2±1.2 (kanamycin treated), whereas those of KCC2 were 115.7±1.5 (control) and 112.0±0.8 (kanamycin treated).ConclusionWe concluded that weak expressions of KCC2 and NKCC1 in circling mice were due to partial destruction of cochleae

Clinical Manifestations of Recurrent Parotid Pleomorphic Adenoma

Objectives. This study was undertaken to confirm the clinical characteristics of recurrent pleomorphic adenoma (RPA), and to identify those factors that affect the development of malignant transformation (MT) from RPA. Methods. The medical records of 270 patients, who were operated upon for parotid PA, were retrospectively reviewed. The pathologic specimens of a selected series of 23 patients were reviewed for histologic subtype and microscopic multi-nodularity. Results. Mean age of initial operation in RPA without MT (RPA(-MT)) group was significantly lower than that of primary PA group. Mean age of the revision operation in RPA with MT (RPA(+MT)) group was significantly greater than that of RPA(-MT) group. Mean interval from operation to recurrence shortened after each revision operation. The risk of MT and additional recurrence increased significantly with recurrence. In RPA(-MT) group tumor recurrence occurred in 21.4% of patients despite a clear resection margin. Conclusion. The risk factors for MT may be an age of over 45 yr and multiple recurrences. However, younger patients are more at risk of recurrence. A clear resection margin cannot guarantee a cure in RPA, and it seems that parotid pleomorphic adenomas slowly gain malignant characteristics after repeated recurrences.SUH MW, 2005, KOREAN J HEAD NECK O, V21, P146HANNA EY, 2005, CUMMINGS OTOLARYNGOL, P1348Ghosh S, 2003, CLIN OTOLARYNGOL, V28, P262Glas AS, 2002, CANCER, V94, P2211, DOI 10.1002/cncr.10445Glas AS, 2001, HEAD NECK-J SCI SPEC, V23, P311BRADLEY PJ, 2001, CURR OPIN OTOLARYNGO, V9, P100Carew JF, 1999, OTOLARYNG HEAD NECK, V121, P539Junquera L, 1999, HEAD NECK-J SCI SPEC, V21, P652Hancock BD, 1999, ANN ROY COLL SURG, V81, P299Bankamp DG, 1999, LARYNGO RHINO OTOL, V78, P77Hoorweg JJ, 1998, EUR J SURG ONCOL, V24, P452Henriksson G, 1998, CANCER, V82, P617Laskawi R, 1998, BRIT J ORAL MAX SURG, V36, P48Klijanienko J, 1997, HEAD NECK-J SCI SPEC, V19, P629Leverstein H, 1997, EUR ARCH OTO-RHINO-L, V254, P313SunardhiWidyaputra S, 1995, PATHOL RES PRACT, V191, P1186PHILLIPS PP, 1995, ANN OTO RHINOL LARYN, V104, P100BUCHMAN C, 1994, LARYNGOSCOPE, V104, P1231NATVIG K, 1994, HEAD NECK-J SCI SPEC, V16, P213JACKSON SR, 1993, J LARYNGOL OTOL, V107, P546MCGREGOR AD, 1988, BRIT J PLAST SURG, V41, P177FEE WE, 1978, LARYNGOSCOPE, V88, P265SEIFERT G, 1976, HNO, V24, P415NAEIM F, 1976, ARCH PATHOL LAB MED, V100, P271FRAZELL EL, 1954, CANCER, V7, P637

Long Term Outcomes of Early Cochlear Implantation in Korea

ObjectivesThe objective of this study was to compare the long-term auditory performance and language skill depending on the age of cochlear implantation in the Korean population. We especially tried to separate the effect of maturation/development from that of the age at implantation.MethodsEighty-six pre-lingual children with profound hearing loss who underwent a cochlear implantation before the age of six and had been followed for more than 3 yr were included in this study prospectively. Categories of Auditory Performance (CAP) and Korean Picture Vocabulary Test (K-PVT) were serially followed up. In order to separate the age at implantation effect, K-PVT results were readjusted to the child's chronological age in the normal hearing population.ResultsWhen the CAP and K-PVT scores were directly compared without chronological readjustment, we failed to show a significant difference for improvements according to the age at implantation. Early cochlear implantation was associated with better language development, only when the K-PVT scores were readjusted to percentile scores of their chronological age.ConclusionEarly cochlear implantation was associated with better language development even within the critical period. This advantage may be recognized only when the effect of the age at implantation is separated from the effect of maturation/development

Clinical Outcomes of Cochlear Reimplantation Due to Device Failure

ObjectivesThe aim of this study was to evaluate the clinical features of cochlear reimplantation due to device failure.MethodsThe medical records of 30 patients who had undergone a revision cochlear implantation were retrospectively reviewed. Causes of revision operations, number of electrode channels inserted, and postoperative speech performances were analyzed.ResultsDevice failure (N=12, 38.7%) and hematoma (N=3, 9.6%) were the two most common reasons for revision surgery. In patients with device failure, the number of electrode channels reinserted was equal to, or more than the number of channels inserted during initial implantation. Speech performance scores remained the same, or improved after reimplantation in patients with device failure.ConclusionDevice failure was the most common cause of revision operation in patients with cochlear implanttion. Contrary to expectation, new electrodes were fully inserted without difficulty in all reimplantation cases. Intracochlear damage due to reimplantation appeared to be clinically insignificant

Resume of Myung Whan Suh, 1993-10

Naval Postgraduate School Faculty Resum