Houyong Kang

Development and evaluation of the Nurotron 26-electrode cochlear implant system.

Although the cochlear implant has been widely acknowledged as the most successful neural prosthesis, only a fraction of hearing-impaired people who can potentially benefit from a cochlear implant have actually received one due to its limited awareness, accessibility, and affordability. To help overcome these limitations, a 26-electrode cochlear implant has been developed to receive Chinas Food and Drug Administration (CFDA) approval in 2011 and Conformité Européenne (CE) Marking in 2012. The present article describes design philosophy, system specification, and technical verification of the Nurotron device, which includes advanced digital signal processing and 4 current sources with multiple amplitude resolutions that not only are compatible with perceptual capability but also allow interleaved or simultaneous stimulation. The article also presents 3-year longitudinal evaluation data from 60 human subjects who have received the Nurotron device. The objective measures show that electrode impedance decreased within the first month of device use, but was stable until a slight increase at the end of two years. The subjective loudness measures show that electric stimulation threshold was stable while the maximal comfort level increased over the 3 years. Mandarin sentence recognition increased from the pre-surgical 0%-correct score to a plateau of about 80% correct with 6-month use of the device. Both indirect and direct comparisons indicate indistinguishable performance differences between the Nurotron system and other commercially available devices. The present 26-electrode cochlear implant has already helped to lower the price of cochlear implantation in China and will likely contribute to increased cochlear implant access and success in the rest of the world. This article is part of a Special Issue entitled .

A new floating piezoelectric microphone for the implantable middle ear microphone in experimental studies

Abstract Conclusions: The new floating piezoelectric microphone is feasible for use as an implantable middle ear microphone in a totally implantable cochlear implant. Objectives: A piezoelectric sensor that is driven by the acoustic vibration of the ossicles is one possible design for a microphone for a totally implantable cochlear implant. Such a new floating piezoelectric microphone has been manufactured in the lab. The purpose of this article was to study the frequency response of the new floating piezoelectric microphone in the intact ossicular chain and to identify whether it is usable and implantable. Methods: The frequency response of the new floating piezoelectric microphone was analyzed using in vitro testing of fresh cadaveric heads. The microphone, which was designed with an integrated unibody structure to ensure good biocompatibility and capsulation, was attached to the long process of the incus by a titanium clip, or placed in the tympanic cavity and stimulated with pure tones of different frequencies. Results: The new floating piezoelectric microphone can pick up the vibration of the long process of the incus and convert it into electrical signals sensitively and flatly.

Objective and subjective evaluations of the Nurotron Venus cochlear implant system via animal experiments and clinical trials.

Abstract Conclusion: This study described objective and subjective evaluations of the Nurotron® Venus™ Cochlear Implant System and indicated that this system produced a satisfactory performance. Objective: To observe the performance of the Nurotron® Venus™ cochlear implant (CI) system via electrophysiological and psychophysical evaluations. Methods: A 26-electrode CI system was specially designed. The performance of MRI in animal and cadaveric head experiments, EABR in cats experiment, the correlation between ESRT and C level, and psychophysics evaluations in clinical trials were observed. Results: In the animal and cadaveric head experiments, magnet dislocation could not be prevented in the 1.5 T MRI without removal of the internal magnet. The EABR was clearly elicited in cat experiment. In the clinical trial, the ESRT was strongly correlated with C level (p < 0.001). The human clinical trial involving 57 post-lingually deafened native Mandarin-speaking patients was performed. Residual hearing protection in the implanted ear at each audiometric frequency was observed in 27.5–46.3% patients post-operatively. A pitch ranking test revealed that place pitches were generally ordered from apical to basal electrodes. The recognitions of the perceptions of 301 disyllabic words, environment sounds, disyllabic words, and numerals were significantly better than the pre-operative performance and reached plateaus.

Knockdown of NFBD1/MDC1 enhances chemosensitivity to cisplatin or 5-fluorouracil in nasopharyngeal carcinoma CNE1 cells

Abstract Nasopharyngeal carcinoma (NPC) is a rare but highly invasive cancer that is prevalent among people of southern Chinese ancestry in southern China and Southeast Asia. Radiotherapy and cisplatin (CDDP)-based chemotherapy are the main treatment options. Unfortunately, disease response to concurrent chemoradiotherapy varies among patients with NPC, and many cases are resistant to CDDP and radiotherapy. NFBD1 functions in cell cycle checkpoint activation and DNA repair following DNA damage. In this study, we identified the NFBD1 as a tractable molecular target to chemosensitize NPC cells. NFBD1 expression in NPC CNE1 cell lines was depleted using lentivirus-mediated short hairpin RNA, and the elevated sensitivity of these NFBD1-inhibited NPC cells to therapeutic reagent CDDP and 5-fluorouracil (5-FU) was evaluated using MTS assays. Flow cytometry analysis also showed that NFBD1 knockdown led to an obvious induction of apoptosis in CDDP- or 5-FU-treated CNE1 cells. Furthermore, we implicated the involvement of NFBD1 in Rad51 and DNA-PKcs foci formation following CDDP or 5-FU chemotherapy. In conclusion, NFBD1 knockdown improves the chemosensitivity of NPC cells by inhibiting cell growth and promoting apoptosis through the impairment of DNA damage repair, suggesting NFBD1 as a novel therapeutic target for NPC.

TrkB promotes laryngeal cancer metastasis via activation PI3K/AKT pathway

Objectives The aim of our study was to investigate the role of TrkB pathway in tumor occurrence and development for in order to provide theoretical basis to laryngeal cancer therapy. Materials and methods Biological characteristics of the cells were studied by migration tests and colony forming assay. Gene and protein expression analysis was performed by RT-PCR or western blot. in vivo experiments were conducted in syngeneic BALB/c mice. Results Significant changes in protein and gene expression, including higher expression level of TrkB, were found in cells and laryngeal cancer specimens. we demonstrated that TrkB activates AKT via c-Src, leading to increased proliferation. Also, TrkB induced EMT via increased expression of EMT related transcription factors such as Twist-1 and Twist-2. Conclusion Our data indicate TrkB are overexpressed in laryngeal cancer, and TrkB signaling is involved in tumorigenicity of laryngeal cancer. These observations suggest that TrkB is a promising target for future intervention strategies to prevent tumor metastasis, EMT program in laryngeal cancer. What is already known about this subject? • Cancer of the larynx is one of the most common types of head and neck cancer. • The survival rate of advanced laryngeal cancer is only 30 to 40%. • The tropomyosin-related kinase B receptor (TrkB), together with TrkA and TrkC, are neurotrophin receptors regulating the proliferation and differentiation of neuronal cells. What are the new findings? • TrkB are overexpressed in laryngeal cancer. • TrkB signaling is involved in tumorigenicity of laryngeal cancer. • TrkB acts as a key regulator of the PI3K/AKT signal pathway-mediated tumor metastasis. How might these results change the focus of research or clinical practice? • These observations suggest that TrkB is a promising target for future intervention strategies to prevent tumor metastasis, EMT program in laryngeal cancer. Our study provides molecular insight into the tumor metastasis and has important implications in elucidating oncogenic processes.

Changes in circulating follicular helper T-cells in Chinese patients with allergic rhinitis.

Abstract Conclusions: Changes of circulating Follicular helper T (cTfh) cells existed in allergic rhinitis (AR) patients, and the severity of disease was associated with a more severe change of cTfh milieu. These results imply that cTfh cells may play a crucial role in the pathology of AR in Chinese patients. Objectives: The aim of this study was to investigate the changes in cTfh cells in Chinese AR patients. Methods: Fifty-two patients were studied (32 in the AR group and 20 in the control group) for this research. The cTfh cell frequency and mRNA levels of transcription factor Bcl-6, B lymphocyte induced maturation protein 1 (BLIMP-1), and related cytokine IL-21 (IL-21 protein was also measured) were analyzed. Clinical severity was evaluated by total serum IgE levels, visual analog scale scores (VAS), and rhino-conjunctivitis quality-of-life questionnaires (RQLQ). Results: The frequency of cTfh cells were elevated in AR groups vs healthy controls (p < 0.05). Levels of IL-21 mRNA, Bcl-6 mRNA and the level of IL-21 protein were also significantly higher in the AR groups (p < 0.05), whereas BLIMP-1 mRNA was decreased (p < 0.05). Furthermore, positive correlations were identified between the frequency of cTfh cells and indicators of clinical severity (p < 0.01).

The airway inflammation induced by nasal inoculation of PM2.5 and the treatment of bacterial lysates in rats

Particulate matter (PM) is one of the most important environmental issues in China. This study aimed to explore the correlation between PM2.5 and airway inflammation in healthy rats. The PM2.5 group was given an intranasal instillation of PM2.5 suspension on 15 consecutive days, and each received oral saline from day 16 to 90. The BV intervention group was treated as the PM2.5 exposure group, except that BV instead of saline was given daily. A histopathologic examination was performed to evaluate the airway inflammation. The prevalence and function of Th1/Th2/Treg/Th17 cells were detected by flow cytometry and ELISA. The expression of AhR was detected by western blot and real-time PCR. We found that epithelial damage and increased infiltration of inflammatory cell were present in the airways after PM2.5 exposure; there was an immune imbalance of Th cells in the PM2.5 group; the expression of AhR was increased in the airways after PM2.5 exposure. In the PM2.5 + BV group, we demonstrated alleviated immune imbalance and reduced inflammatory cell infiltration in the airways. Our study showed that exposure to PM2.5 induced airway inflammation. The imbalance of Th1/Th2/Treg/Th17 in PM2.5-induced airway inflammation might be associated with activation of the AhR pathway. Oral BV reduces PM2.5-induced airway inflammation and regulates systemic immune responses in rats.

Exposure to air pollution and risk of prevalence of childhood allergic rhinitis: A meta-analysis

OBJECTIVES Allergic rhinitis (AR), a common chronic inflammatory disease in the upper airways. The prevalence of AR in children seems to be increasing recently, and the most significant causes of the increase are thought to be changes in environmental factors, especially air pollution. However, we could not find any meta-analysis on the risk of air pollution exposure on the prevalence of AR in childhood. The aim of this research was to carry out a meta-analysis on the results of recent studies (21 s t century) to present valid information about exposure to air pollution and risk of prevalence of childhood AR. METHODS PubMed, Science, Google Scholar, Elsevier and MDPI web database were searched up to January 1, 2000 to February 28, 2018. Including of air pollution and AR in childhood related to the observation of literature. Meta-analysis, study quality assessment, heterogeneity analysis and publication bias test were using Stata-MP 14.1 and Review Manager version 5.3 software. RESULTS 13 studies will be included in the meta-analysis (8 cross-sectional studies, 5 cohort studies). Exposure to NO2 (OREurope = 1.031, 95%CI [1.002,1.060], P = 0.033; ORAsia = 1.236, 95%CI [1.099,1.390], P = 0.000; ORoverall = 1.138, 95%CI [1.052,1.231], P = 0.001); Exposure to SO2 (OREurope = 1.148, 95%CI [1.030,1.279], P = 0.012; ORAsia = 1.044, 95%CI [0.954,1.142], P = 0.352; ORoverall = 1.085, 95%CI [1.013,1.163], P = 0.020); Exposure to PM10 (OREurope = 1.190, 95%CI [1.092,1.297], P = 0.000; ORAsia = 1.075, 95%CI [0.995,1.161], P = 0.066; ORoverall = 1.125, 95%CI [1.062,1.191], P = 0.000); Exposure to PM2.5 (OREurope = 1.195, 95%CI [1.050,1.360], P = 0.007; ORAsia = 1.163, 95%CI [1.074,1.260], P = 0.000; ORoverall = 1.172, 95%CI [1.095,1.254], P = 0.000). CONCLUSIONS Exposed to air pollution probable is a risk of prevalence of childhood AR. And the prevalence of AR will be increase when exposed to NO2, SO2, PM10 and PM2.5, but maybe the relationship between SO2/PM10 and prevalence of AR are not closely in Asia.

Associations of single nucleotide polymorphisms of PTPN22 and Ctla4 genes with the risk of allergic rhinitis in a Chinese Han population

BACKGROUND Allergic rhinitis (AR) is an inflammatory disorder of the upper airway. Protein tyrosine phosphatase non-receptor 22 encoded by PTPN22 gene and cytotoxic T-lymphocyte associated 4 encoded by Ctla4 gene are associated with autoimmune diseases. PURPOSE This study was performed to evaluate the potential association of PTPN22 and Ctla4 single nucleotide polymorphisms (SNPs) with AR in a Chinese Han population. METHODS A case-control study was performed in 783 Chinese AR patients and 811 healthy controls. Three SNPs in PTPN22 gene (rs2488457, rs1310182, and rs3789604) and 6 SNPs in Ctla4 gene (rs3087243, rs231779, rs11571302, rs11571315, rs231725, and rs35219727) were detected using a polymerase chain reaction-restriction fragment length polymorphism assay (PCR-RFLP). RESULTS For PTPN22 gene, a significantly decreased prevalence of the rs2488457 CC genotype and C allele was found in AR patients. The frequencies of the rs1310182 CC genotype, CT genotype, and C allele were significantly associated with the risk of AR. For Ctla4 gene, a significantly increased prevalence of the rs11571302 AA genotype, CA genotype and A allele was noted in AR patients. CONCLUSION SNPs of PTPN22 and Ctla4 genes are significantly associated with the risk of AR in the Chinese Han population.