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Medicine, South Korea

Choi C.H.,Research Center for Resistan Cells | Pak S.C.,Charles Sturt University | Jang C.H.,Research Center for Resistan Cells | Jang C.H.,Chonnam National University
International Journal of Pediatric Otorhinolaryngology | Year: 2016

Background & objective: The effect of direct application of local lidocaine with epinephrine on the facial nerve (FN) has not been reported. The aim of this study is to assess the effects of 2% lidocaine with 1:100,000 epinephrine at clinically relevant concentrations in a rat FN model with respect to facial nerve blood flow (FNBF) and subsequent electrophysiological changes. Materials and methods: To assess the influence of drugs on FNBF and electrically evoked muscle action potential (EMAP), small pieces of gelfoam were soaked in PBS 100 μl (n = 5, control group), 50 μl (n = 5, treatment group A) and 100 μl (n = 5, group B) of 2% lidocaine with 1:100,000 epinephrine, and 50 μl (n = 5, group C) and 100 μl (n = 5, group D) of 2% lidocaine. After 5 min of stable recordings, we applied a 2% lidocaine with or without 1:100,000 epinephrine impregnated gelfoam over the main trunk of the facial nerve of rats for 30 min. After removing the applied gelfoam, FNBF and threshold of EMAP were measured separately in each group. Results: Compared to the control group, the treatment groups showed a significant reduction in FNBF in a dose-dependent manner. The maximal reductions in FNBF were observed in all treatment groups for a period after 10 min of the application. Synergistic reduction in FNBF was greater in groups A and B than in the lidocaine applied groups (C and D). The maximal increase in the EMAP threshold was observed immediately after the respective drug application in all groups. The greatest increase in the EMAP threshold was observed in group B. The increased EMAP threshold returned to the baseline value within 120 min in groups A and C. Conclusion: From these results, it can be considered that the topical application of lidocaine with epinephrine caused reduction in FNBF and elevation of EMAP threshold. These acute reductions in FNBF and elevations in the EMAP threshold were restored in a time-dependent manner. © 2016 Elsevier Ireland Ltd.

Jang C.H.,Chonnam National University | Jang C.H.,Research Center for Resistan Cells | Cho Y.B.,Chonnam National University | Kim J.S.,Chonnam National University | And 2 more authors.
Laryngoscope | Year: 2012

Objectives/Hypothesis: The study aimed to regenerate pneumatic air cells in guinea pig bulla using three-dimenisonal (3D) biocomposite scaffolds consisting of polycaprolactone/β-tricalcium phosphate (PCL/β-TCP). Study Design: Prospective controlled study in experimental animals. Methods: PCL/β-TCP composites were implanted into the bulla with mucosa preservation in group A (n = 10). PCL/β-TCP composites coated with collagen were implanted in group B (n = 10). After 12 weeks, the bullae were extracted and evaluated by micro-computed tomography (micro-CT) and were processed for histological analyses. Results: In group A, micro-CT showed a well-maintained honeycomb appearance of micropores without obstruction. Regeneration of the mucosa was noted inside the pores of the 3D scaffold. However, partial obstruction of the micropores with new bone formation was evident in group B. Conclusions: Group A showed more satisfactory mucosal regeneration into the micropores. Our results indicate that the 3D scaffold may be amenable for use during mastoidectomy. Further studies for gas exchange in the regenerated mucosa are necessary. © 2012 The American Laryngological, Rhinological and Otological Society, Inc.

Jang C.H.,Chonnam National University | Jang C.H.,Research Center for Resistan Cells | Cho Y.B.,Chonnam National University | Yeo M.G.,Sungkyunkwan University | Kim G.H.,Sungkyunkwan University
Macromolecular Bioscience | Year: 2013

Two different composite scaffolds, solid-freeform-fabricated PCL/β-TCP supplemented with and without collagen nanofibers are fabricated. These scaffolds are evaluated whether a combination of collagen nanofibers with PCL/β-TCP can promote osteogenesis in a mastoid obliteration. To assess the effects of the cellular activities of osteoblast-like-cells (MG63), SEM images and MTT assays are conducted. Experimental mastoid obliteration is performed using guinea pigs that are divided group A (PCL/β-TCP/collagen-nanofiber scaffold) and group B (PCL/β-TCP scaffold). The results reveal that PCL/β-TCP/collagen scaffold provide much broader cell attachment sites than PCL/β-TCP scaffold. The μ-CT and fluorescent microscopy results reveal that the acceleration of early new bone formation within the pores and scaffold itself at week 4 post-operation is more effective in group A. In addition, based on the results of the histological and μ-CT at 12 weeks post-surgery, the effective regeneration of bone in the PCL/β-TCP/collagen scaffold is appeared. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Jang C.H.,Chonnam National University | Jang C.H.,Research Center for Resistan Cells | Cho Y.B.,Chonnam National University | Yeo M.,Sungkyunkwan University | And 4 more authors.
International Journal of Biological Macromolecules | Year: 2013

Chronic tympanic membrane (TM) perforation is one of the most common otology complications. Current surgical management of TM perforation includes myringoplasty and tympanoplasty. The purpose of this study was to evaluate the efficacy and feasibility of three dimensional (3D) porous collagen scaffolds with topically applied human umbilical cord serum (UCS) for the regeneration of chronic TM perforation in guinea pigs. To achieve this goal, we fabricated porous 3D collagen scaffolds (avg. strut diameter of 236. ±. 51. μm, avg. pore size of 382. ±. 67. μm, and a porosity of 96%) by using a 3 axis robot dispensing and low temperature plate systems. Guinea pigs were used in a model of chronic TM perforation. In the experimental group (. n=. 10), 3D collagen scaffold was placed on the perforation and topically applied of UCS every other day for a period of 8 days. The control group ears (. n=. 10) were treated with paper discs and phosphate buffered saline (PBS) only using the same regimen. Healing time, acoustic-mechanical properties, and morphological analysis were performed by otoendoscopy, auditory brainstem response (ABR), single-point laser Doppler vibrometer (LDV), optical coherence tomography (OCT), and light microscopic evaluation. The closure of the TM perforation was achieved in 100% of the experimental group vs. 43% of the control group, and this difference was statistically significant (. p=. 0.034). The ABR threshold at all frequencies of the experimental group was significantly recovered to the normal level compared to the control group. TM vibration velocity in the experimental group recovered similar to the normal control level. The difference is very small and they are not statistically significant below 1. kHz (. p=. 0.074). By OCT and light microscopic examination, regenerated TM of the experimental group showed thickened fibrous and mucosal layer. In contrast, the control group showed absence of fibrous layer like a dimeric TM. © 2013 Elsevier B.V.

Jang C.H.,Chonnam National University | Jang C.H.,Research Center for Resistan Cells | Jo S.Y.,Chonnam National University | Cho Y.B.,Chonnam National University
Acta Oto-Laryngologica | Year: 2013

Conclusion: Matrix removal by a non-suction technique with intraoperative dexamethasone injection is a safe and effective management modality, regardless of fistula size. Objective: Our goal was to evaluate the outcome of hearing treated by non-suction technique with intraoperative dexamethasone injection. Methods: This was a retrospective chart review of 720 mastoidectomy cases for cholesteatoma, performed at our tertiary otolaryngologic care centers between 2005 and 2012. A total of 17 patients with a unilateral labyrinthine fistula were encountered. Results: There was no recurrent cholesteatoma in any of the patients. In all cases, the matrix was removed by intraoperative dexamethasone injection with a bimanual non-suction technique, regardless of the fistula size. None of the patients showed deteriorated bone conduction (BC). Averaged BC was unchanged (n = 13) or improved (n = 4) in all patients and did not decrease by 10 dB more in any patient. The mean threshold of postoperative BC was significantly improved compared with preoperative mean threshold. Fistulae on the preoperative CT scans ranged from 1.41 to 7.12 mm and averaged 2.89 mm. There was no correlation between the fistula size and the postoperative BC level. Even with a large fistula, postoperative hearing preservation was possible with one-stage matrix removal. © 2013 Informa Healthcare.

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