ABSTRACT
In mammals, the piezoelectric protein, Prestin, endows the outer hair cells (OHCs) with electromotility (eM), which confers the capacity to change cellular length in response to alterations in membrane potential. Together with basilar membrane resonance and possible stereociliary motility, Prestin-based OHC eM lays the foundation for enhancing cochlear sensitivity and frequency selectivity. However, it remains debatable whether Prestin contributes to ultrahigh-frequency hearing due to the intrinsic nature of the cell's low-pass features. The low-pass property of mouse OHC eM is based on the finding that eM magnitude dissipates within the frequency bandwidth of human speech. In this study, we examined the role of Prestin in sensing broad-range frequencies (4-80 kHz) in mice that use ultrasonic hearing and vocalization (to >100 kHz) for social communication. The audiometric measurements in mice showed that ablation of Prestin did not abolish hearing at frequencies >40 kHz. Acoustic associative behavior tests confirmed that Prestin-knockout mice can learn ultrahigh-frequency sound-coupled tasks, similar to control mice. Ex vivo cochlear Ca2+ imaging experiments demonstrated that without Prestin, the OHCs still exhibit ultrahigh-frequency transduction, which in contrast, can be abolished by a universal cation channel blocker, Gadolinium. In vivo salicylate treatment disrupts hearing at frequencies <40 kHz but not ultrahigh-frequency hearing. By pharmacogenetic manipulation, we showed that specific ablation of the OHCs largely abolished hearing at frequencies >40 kHz. These findings demonstrate that cochlear OHCs are the target cells that support ultrahigh-frequency transduction, which does not require Prestin.
Subject(s)
Animals , Humans , Mice , Cochlea/metabolism , Hair Cells, Auditory, Outer/metabolism , Hearing , Mammals/metabolism , Mice, Knockout , Molecular Motor Proteins/metabolismABSTRACT
Objective To evaluate the value of 3.0T magnetic resonance multi-b value diffusion-weighted imaging (DWI) in evaluating the efficacy of chemotherapy for patients with central lung squamous cell carcinoma and atelectasis. Methods Twenty patients with lung squamous cell carcinoma were examined by magnetic resonance imaging (MRI) (including T1WI, T2WI and multi-b value DWI) before chemotherapy, 2 cycles of chemotherapy and 4 cycles of chemotherapy. The images, the tumor volume and changes of apparent diffusion coefficient (ADC) were analyzed. Results In the patients with central lung cancer and atelectasis, the tumor and atelectasis could be distinguished on MRI examination before radiotherapy. It was more easily identified on T2WI images after radiotherapy. In the 20 patients, the ADC values in the effective group (partial remission or complete remission) and the invalid group were increased, but the differences of ADC values in the effective group before chemotherapy, 2 cycles and 4 cycles of chemotherapy were statistically significant [b=800 s/mm2:(1.09 ± 0.52) × 10-6 mm2/s, (1.22 ± 0.59) × 10-6 mm2/s, (1.24 ± 0.52) × 10-6 mm2/s, F = 31.19, P < 0.001]. There was no significant difference in ADC values between before and after chemotherapy (b = 800 s/mm2: (1.10 ± 0.49) × 10-6 mm2/s, (1.16 ± 0.60) × 10-6 mm2/s, (1.20 ± 0.72) × 10-6 mm2/s, F=2.86, P=0.089]. When b=800 s/mm2, the ADC curve slope in the effective group was more stable, better linearity. Conclusions The MRI technique can accurately distinguish the tumor from atelectasis before and after chemotherapy. The change of ADC value after chemotherapy is earlier than that of morphological change. The change rate of b value can better evaluate the curative effect of chemotherapy.
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Objective To explore the HRCT characteristics of solitary pure bronchioloalveolar carcinoma.Methods Compared with postop pathological appearance,21 patients with 22 affections tumors which were pathologically confirmed pure bronchioloalveolar carcinoma were retrospectively reviewed.Results the histopathological results prior to surgery showed that 20 patients with 21 affections tumors were non-mucilaginous BAC and 1 patient was mucilaginous BAC.Noguchi's classification:Type A 3 cases,Type B 12 cases,Type C 5 cases.(Mucilaginous BAC was not classified)Stage classification:There were 21 cases with stage ⅠA,the maximum tumor diameter was from 0.3 to 3.0 mm (average diameter 1.3 mm).No case showed pleura metastasis,vessel invasion and lymphaticmetastasis.Appearance of HRCT:according to the amount of GGO,all affections were divided into 4 groups.A group(5/22),B group(7/22),C group(7/22),D group(3/22).There were 11 cases with pleura traction,5 cases with clear boundary and trimmed edges and other 17 cases were contradistinction.There were 21 cases with blood vessel or bronchus shadow.Conclusion HRCT can show scan can provide details of structure characteristics of BAC's pathological histology,so it plays an important role in prediction of pathological infiltration of tumor cells and prognosis assessment.
ABSTRACT
Objective To investigate CT feature after contrast-enhanced and anatomic distribute of the whole body lymph nodes involved by lymphoma. Methods The whole body CT findings in 89 cases (HL 12 cases, NHL 77 cases) of malignant lymphoma were retrospectively analyzed. The contrast-enhanced CT features (size, density and the digree of contrast enhancement) and anatomic distribution of the whole body lymph nodes involved by lymphoma were clarified. Results In the HL group, Diffuse and homogeneous enhancement of the enlarged lymph nodes was found in 9 cases (75.0 %), while homogeneous enhancement of the enlarged lymph nodes with some little necrosis was found in 3 cases (25.0 %). In the NHL group, diffuse and homogeneous enhancement of the enlarged lymph nodes was found in 64 cases (83.1 %), while homogeneous enhancement of the enlarged lymph nodes with some little necrosis was found in 13 cases (16.9 %). There was not statistically significant (Fisher exact probability, P = 0.4461) between the two groups. In the HL group, the enlarged lymph nodes were mixed together in 6 cases (50.0 %), while the enlarged lymph nodes were separate in 6 cases (50.0 %). In the NHL group, the enlarged lymph nodes were mixed together in 8 cases (10.4 %), while the enlarged lymph nodes were separate in 69 cases (89.6 %), there was statistically significant (Fisher exact probability, P = 0.0028). The dominant anatomic distributions of the lymph nodes involved by HL group were neck and mediastinum. The dominant anatomic distributions of the lymph nodes involved by NHL group were neck, mediastinum and abdomen, there was not statistically significant between the anatomic distributions (Fisher exact probability, P =0.110). Conclusion CT can easily demonstrate the involvement and extension of malignant involving the whole body, but CT can not differentiate HL and NHL except for the confluence state.