Study on conditional myosin light chain kinase gene knockout mice resulting in hearing loss / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To investigate the function of myosin light chain kinase (MLCK) in hearing in mouse by generating inner hair cell-specific Mlck knockout mice and analyze the effect on their hearing.</p><p><b>METHODS</b>Cross Mlck floxed mice with IHC-Cre mice, the genotype and knockout efficiency were confirmed by PCR. We used auditory brain stem response (ABR) to evaluate mice hearing function at different frequencies.</p><p><b>RESULTS</b>Mlck knockout mice were selected by mice tail DNA genotyping and confirmed the deletion of the target gene by isolated inner hair cell DNA genotyping. Mlck-deficient mice showed impaired hearing with a rise in ABR threshold response to click and three different pure tones (8 kHz, 16 kHz, 32 kHz), and the rise was over 20 dB at high-frequency(32 kHz). Further analyses of waveforms showed that wave-I amplitudes on 60 dB SPL, 50 dB SPL and 40 dBSPL in response to tone (16 kHz) were less than control group(P < 0.05) on average, but the ratio of wave I/II and I/III were not difference (P > 0.05).</p><p><b>CONCLUSIONS</b>Mlck is successfully deleted in inner hair cell-specific Mlck knockout mice. Mlck knockout mice display a significantly higher threshold in response to click and tones, especially in high-frequencies.</p>

Expression of E-cadherin and uPA and their prognostic value in carcinoma of human larynx / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To investigate the expression of E-cadherin (ECD) and uPA in laryngeal cancer and evaluate their clinical value in prognosis.</p><p><b>METHODS</b>ECD and uPA were determined by immunohistochemistry of Envision methods in carcinoma tissues of 51 patients of laryngeal carcinoma. All patients were followed and the prognostic factors were analyzed.</p><p><b>RESULTS</b>Among 51 patients' tumor tissues, 24 (47.1%) were negative expression of ECD, and 26 (51.0%) were positive uPA immunoreaction was observed. There were four subgroups of patterns of ECD and uPA expression: 14 (27.1%) ECD-positive/uPA-negative, 13 (25.5%) ECD-negative/uPA-negative, 11 (21.6%) ECD-positive/uPA-positive, and 13 (25.5%) ECD-negative/uPA-positive. The tumor tissues with ECD-negative and uPA-positive expression were significant associated with lymph nodes metastasis (chi(2) = 5.545, 5.79, P = 0.019, 0.016 respectively). Patients with ECD-negative expression had a shorter survival than the patients with ECD positive expression but no statistic difference (chi(2) = 2.534, P > 0.05). Patients with uPA-positive expression had a significantly shorter survival time than those with uPA-negative expression (chi(2) = 6.259, P < 0.05). There was a difference for the median survival time between the patients with uPA-negative/ECD-positive and the patients with uPA-positive/ECD-negative in laryngeal cancer tissue (chi(2) = 6.559, P = 0.01), and the survival curves between these two groups was also statistically significant difference. Multivariate analysis of Cox revealed that clinical stage and ECD/uPA (P = 0.009, 0.007 respectively) were two independent prognostic factors.</p><p><b>CONCLUSIONS</b>The combination analysis of uPA and ECD immunohistochemical expression in the laryngeal cancer tissue may be useful for predicting tumor metastatic risks and patient's prognosis.</p>