Cheng-Ping Shih

Ultrasound-aided microbubbles facilitate the delivery of drugs to the inner ear via the round window membrane

The round window membrane (RWM) acts as a barrier between the middle ear and cochlea and can serve as a crucial route for therapeutic medications entering the inner ear via middle ear applications. In this study, we targeted the practical application of microbubbles (MBs) ultrasound on increasing the RWM permeability for facilitating drug or medication delivery to the inner ear. Using biotin-fluorescein isothiocyanate conjugates (biotin-FITC) as delivery agents and guinea pig animal models, we showed that MB ultrasound exposure can improve the inner ear system use of biotin-FITC delivery via the RWM by approximately 3.5 to 38 times that of solely soaking biotin-FITC around the RWM for spontaneous diffusion. We also showed that there was significant enhancement of hair cell uptake of gentamicin in animals whose tympanic bullas were soaked with MB-mixed gentamicin-Texas Red or gentamicin and exposed to ultrasound. Furthermore, increased permeability of the RWM from acoustic cavitation of MBs could also be visualized immediately following ultrasound exposure by using Alexa Fluor 488-conjugated phalloidin as a tracer. Most importantly, such applications had no resulting damage to the integrity of the RWM or deterioration of the hearing thresholds assessed by auditory brainstem responses. We herein provide a basis for MB ultrasound-mediated techniques with therapeutic medication delivery to the inner ear for future application in humans.

Hypoxia Induces a Metabolic Shift and Enhances the Stemness and Expansion of Cochlear Spiral Ganglion Stem/Progenitor Cells

Previously, we demonstrated that hypoxia (1% O2) enhances stemness markers and expands the cell numbers of cochlear stem/progenitor cells (SPCs). In this study, we further investigated the long-term effect of hypoxia on stemness and the bioenergetic status of cochlear spiral ganglion SPCs cultured at low oxygen tensions. Spiral ganglion SPCs were obtained from postnatal day 1 CBA/CaJ mouse pups. The measurement of oxygen consumption rate, extracellular acidification rate (ECAR), and intracellular adenosine triphosphate levels corresponding to 20% and 5% oxygen concentrations was determined using a Seahorse XF extracellular flux analyzer. After low oxygen tension cultivation for 21 days, the mean size of the hypoxia-expanded neurospheres was significantly increased at 5% O2; this correlated with high-level expression of hypoxia-inducible factor-1 alpha (Hif-1α), proliferating cell nuclear antigen (PCNA), cyclin D1, Abcg2, nestin, and Nanog proteins but downregulated expression of p27 compared to that in a normoxic condition. Low oxygen tension cultivation tended to increase the side population fraction, with a significant difference found at 5% O2 compared to that at 20% O2. In addition, hypoxia induced a metabolic energy shift of SPCs toward higher basal ECARs and higher maximum mitochondrial respiratory capacity but lower proton leak than under normoxia, where the SPC metabolism was switched toward glycolysis in long-term hypoxic cultivation.

Surgical Results of Retrograde Mastoidectomy with Primary Reconstruction of the Ear Canal and Mastoid Cavity

The aim of this study was to retrospectively review the long-term hearing results and the impact of mastoid exclusion/obliteration in patients with cholesteatoma (102 ears) who underwent retrograde tympanomastoidectomy and in whom bone chips/paté were applied as the sole materials during the procedure. In 79 ears, this was combined with ossiculoplasty in a single-stage procedure. In >71% of ears, the results of audiometric testing were monitored for more than 2 years. The results suggested there was a significant gain in hearing following surgery, with respect to the postoperative change in both air-conduction thresholds and air-bone gaps (P < 0.001). Linear regression analyses of pure-tone averages at different frequencies, before and after surgery, demonstrated that patients benefitted from a postoperative hearing gain at low and middle frequencies, but their hearing often deteriorated at frequencies of 8000 Hz. As for the impact of the type of tympanoplasty on hearing outcomes, type III-interposition markedly increased hearing gain. The overall rate of postoperative adverse events was 8.8%. We conclude that reconstruction of the ear canal and mastoid via mastoid exclusion/obliteration using bone chips/paté can be considered as an alternative procedure following retrograde mastoidectomy. It gives excellent surgical results and has fewer postoperative adverse events.

Effects of Microbubble Size on Ultrasound-Mediated Gene Transfection in Auditory Cells

Gene therapy for sensorineural hearing loss has recently been used to insert genes encoding functional proteins to preserve, protect, or even regenerate hair cells in the inner ear. Our previous study demonstrated a microbubble- (MB-)facilitated ultrasound (US) technique for delivering therapeutic medication to the inner ear. The present study investigated whether MB-US techniques help to enhance the efficiency of gene transfection by means of cationic liposomes on HEI-OC1 auditory cells and whether MBs of different sizes affect such efficiency. Our results demonstrated that the size of MBs was proportional to the concentration of albumin or dextrose. At a constant US power density, using 0.66, 1.32, and 2.83 μm albumin-shelled MBs increased the transfection rate as compared to the control by 30.6%, 54.1%, and 84.7%, respectively; likewise, using 1.39, 2.12, and 3.47 μm albumin-dextrose-shelled MBs increased the transfection rates by 15.9%, 34.3%, and 82.7%, respectively. The results indicate that MB-US is an effective technique to facilitate gene transfer on auditory cells in vitro. Such size-dependent MB oscillation behavior in the presence of US plays a role in enhancing gene transfer, and by manipulating the concentration of albumin or dextrose, MBs of different sizes can be produced.

TRPC1 is required for survival and proliferation of cochlear spiral ganglion stem/progenitor cells

OBJECTIVE The present studies were designed to test the hypothesis that canonical transient receptor potential channel 1 (TRPC1) is required for the proliferation of cochlear spiral ganglion stem/progenitor cells (SPCs). METHODS AND MATERIALS TRPC1 were detected and evaluated in postnatal day 1 CBA/CaJ mice pups derived-cochlear spiral ganglion SPCs by reverse transcription-polymerase chain reaction, Western blot, immunocytochemistry, and calcium imaging. The cell viability and proliferation of the spiral ganglion SPCs following si-RNA mediated knockdown of TRPC1 or addition of TRPC channel blocker SKF9635 were compared to controls. RESULTS In spiral ganglion SPCs, TRPC1 was found to be the most abundantly expressed TRPC subunit and shown to contribute to store-operated calcium entry. Silencing of TRPC1 or addition of TRPC channel blockers significantly decreased the rate of cell proliferation. CONCLUSION The results suggest that TRPC1 might serve as an essential molecule in regulating the proliferation of spiral ganglion SPCs.

The correlation between lipoprotein ratios and hearing outcome in idiopathic sudden sensorineural hearing loss patients

Recent reports have identified hypercholesterolaemia as a significant risk factor for idiopathic sudden sensorineural hearing loss (ISSNHL). Therefore, we investigated whether lipid profiles and lipoprotein ratios are correlated with the prognosis of hearing recovery in ISSNHL patients.

T-cell lymphoma manifesting as a uvular mass

A 54-year-old woman had a 5-year history of RA on regular medication presented with a 3-month history of swelling in her throat and muffled voice. Physical examination revealed a uvular mass (Fig. 1A). CT showed an ill-defined mass in the oropharynx (Fig. 1B) and small enhancing cervical lymph nodes. Oropharyngeal biopsy identified the mass as a malignant T-cell lymphoma. Wholebody PET showed increased fluorodeoxyglucose uptake in the oropharynx and cervical lymph nodes. She achieved partial remission after three courses of cyclophosphamide + hydroxydoxorubicin + oncovin + prednisone (CHOP) chemotherapy but died of sepsis before the fourth course. Several autoimmune diseases, including SS, SLE, cryoglobulinaemia and RA, are associated with an elevated risk of lymphoma development [1]. Peripheral T-cell lymphoma is aggressive with a high relapse rate despite the currently available chemotherapies. More than half of extranodal head and neck lymphomas occur in Waldeyer’s ring, and those expressing T-cell markers arise predominantly in the paranasal sinuses and nasal cavity. Oropharyngeal involvement from peripheral T-cell lymphoma is extremely rare.

The association of superior attachment of uncinate process with pneumatization of middle turbinate: a computed tomographic analysis

The frontal sinus outflow pathway is complex and can be influenced by the configuration of the uncinate process (UP). The UP can attach superior to the lamina papyracea, skull base, and middle turbinate. The factors associated with superior attachment remain unclear. This study analyzed the relationships between different types of superior UP attachment and characteristics of the surrounding structures including the agger nasi cell, skull base, and middle turbinate. This retrospective study utilized computed tomography images of 836 sides with identifiable sinus structure from 434 Taiwanese patients. Types of superior UP attachment, height of the ethmoid cribriform plate, prevalence of agger nasi cell, and degree of pneumatization of the middle turbinate were analyzed. In the current study, neither the presence of an agger nasi cell nor height of the cribriform plate had significant relationship with superior UP attachment type. However, UP attachment type was statistically significantly associated with pneumatized middle turbinate (PMT) type (p < 0.01). The PMT group had a higher incidence of UP attachment to the middle turbinate (38%) than the non-PMT group (18%). In the extensive PMT group, the incidence of UP attachment to the middle turbinate was high to 49%. In conclusion, superior UP attachment to the middle turbinate was associated with pneumatization of the middle turbinate. The UP has a greater tendency to attach to the middle turbinate in cases with more PMT.

Diode Laser-assisted Excision of Glomus Tympanicum Tumor: Do Diode Lasers Help in Hemostasis and Tumor Removal?

This report focuses on the use of a diode laser on a 37-year-old woman with a glomus tympanicum tumor that completely filled her middle ear space. Through a postauricular approach, the exposed vascular tumor was gently coagulated to shrink it and sectioned to detach it from the middle ear using a diode laser, followed by the piecemeal removal of the tumor in toto. Ossicular reconstruction was performed in a single-stage tympano-ossiculoplasty. The patient had an uneventful postoperative course, and the audiometry revealed a complete closure of the air-bone gap one year after the operation. Due to its flexible delivery system that can sufficiently work in such restricted middle ear spaces, the application of the diode laser to treat the glomus tympanicum allowed adequate hemostasis to be achieved while avoiding subsequent sequelae. We demonstrate that the diode laser is a well applicable tool in treating highly vascular tumors of the middle ear like glomus tympanicum.

Bilateral Auricular Pseudocyst

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