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1.
Tympanic membranes (TM) that have healed spontaneously after perforation present abnormalities in their structural and mechanical properties; i.e., they are thickened and abnormally dense. These changes result in a deterioration of middle ear (ME) sound transmission, which is clinically presented as a conductive hearing loss (CHL). To fully understand the ME sound transmission under TM pathological conditions, we created a gerbil model with a controlled 50% pars tensa perforation, which was left to heal spontaneously for up to 4 weeks (TM perforations had fully sealed after 2 weeks). After the recovery period, the ME sound transmission, both in the forward and reverse directions, was directly measured with two-tone stimulation. Measurements were performed at the input, the ossicular chain, and output of the ME system, i.e., at the TM, umbo, and scala vestibuli (SV) next to the stapes. We found that variations in ME transmission in forward and reverse directions were not symmetric. In the forward direction, the ME pressure gain decreased in a frequency-dependent manner, with smaller loss (within 10 dB) at low frequencies and more dramatic loss at high frequency regions. The loss pattern was mainly from the less efficient acoustical to mechanical coupling between the TM and umbo, with little changes along the ossicular chain. In the reverse direction, the variations in these ears are relatively smaller. Our results provide detailed functional observations that explain CHL seen in clinical patients with abnormal TM, e.g., caused by otitis media, that have healed spontaneously after perforation or post-tympanoplasty, especially at high frequencies. In addition, our data demonstrate that changes in distortion product otoacoustic emissions (DPOAEs) result from altered ME transmission in both the forward and reverse direction by a reduction of the effective stimulus levels and less efficient transfer of DPs from the ME into the ear canal. This confirms that DPOAEs can be used to assess both the health of the cochlea and the middle ear.  相似文献   
2.
Zhao  Xiu-Juan  Zhang  Yi-Ran  Bai  Wen-Fei  Sun  Tong-Yan  Yang  Yu-Fen  Wang  Tong-Xin  Bai  Cui-Gai 《Inflammopharmacology》2022,30(5):1717-1728
Inflammopharmacology - The efficacy of the sulforaphane derivative JY4 was evaluated in acute and chronic mouse models of ulcerative colitis induced by dextran sodium sulfate. Oral administration...  相似文献   
3.
AIM:To summarize the data of epidemiological studies on cataract prevalence over 50 years old in urban and rural areas of China from 2000 to 2020,and to analyze the prevalence of cataract and operation rate in China.METHODS:By searching Pub Med,EMBASE,Web of Science,Wanfang Data and CNKI,Chinese and English literatures on the prevalence of cataract in China were retrieved,and the relevant characteristic data were extracted.Then,Stata v15 SE software was used for Metaanalysis and heterogeneity test.According to the results of heterogeneity,the corresponding effect models were selected to combine the extracted data.RESULTS:A total of 20 studies were included in this study,with a total of 111434 cases.Meta-analysis showed heterogeneity.According to the random effect model,the overall prevalence of cataract in Chinese people over 50 years old was 27.45%,that in rural was 28.79%,and that in urban was 26.66%.The overall coverage rate of cataract surgery was 9.19%.CONCLUSION:The prevalence of cataract is high in China,and there is still room for improvement in surgical coverage,so it is very important to promote cataract screening and prevention.  相似文献   
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摘要:WAP-8294A是从Lysobacter sp.发酵液中分离得到的环状脂肽类抗生素。其主要产物WAP-8294A2(lotilibcin)对耐甲氧 西林金黄色葡萄球菌(MRSA)具有强抑制活性,该类化合物通过选择性识别存在于革兰阳性细菌细胞质膜中的甲基萘醌(MK), 破坏细胞膜来杀死细胞,但其低产量限制了工业化生产。本文综述了近年来WAP-8294A类抗生素的研究进展,重点介绍了该类 化合物的起源及生物合成;活性靶点及其构效关系;产量提高策略。为后续探索WAP-8294A类抗生素大规模生产的最适条件及 设计其高活性衍生物奠定基础。  相似文献   
6.
目的探讨一种自拟中药配方制成的护膝治疗膝关节骨性关节炎(knee osteoarthritis,KOA)的临床疗效。方法本次研究选择2020年6月至12月于联勤保障部队临潼康复疗养中心进行治疗的160例确诊为KOA的患者作为研究对象,根据临床治疗方法将全部患者随机分成两组,每组80例,比较两组临床效果。结果比较后发现,总有效率观察组为61.25%;对照组为37.50%,差异有统计学意义;膝关节Lysholm评分对比显示,两组患者的膝关节功能都有明显改善,且观察组治疗效果明显优于对照组,差异有统计学意义。结论该自制护膝对于KOA患者有很好的治疗效果,能显著改善患者关节的各项功能。  相似文献   
7.
IntroductionAlthough hyperferritinemia may reflect the inflammatory status of patients with non-alcoholic fatty liver disease (NAFLD), approximately 33% of hyperferritinemia cases reflect real hepatic iron overload.AimTo evaluate a non-invasive method for assessing mild iron overload in patients with NAFLD using 3T magnetic resonance imaging (MRI) relaxometry, serum hepcidin, and the expression of ferritin subunits.MethodsThis cross-sectional study assessed patients with biopsy-proven NAFLD. MRI relaxometry was performed using a 3T scanner in all patients, and the results were compared with iron content determined by liver biopsy. Ferritin, hepcidin, and ferritin subunits were assessed and classified according to ferritin levels and to siderosis identified by liver biopsy.ResultsA total of 67 patients with NAFLD were included in the study. MRI revealed mild iron overload in all patients (sensitivity, 73.5%; specificity, 70%). For mild (grade 1) siderosis, the transverse relaxation rate (R2*) threshold was 58.9 s?1 and the mean value was 72.5 s?1 (SD, 33.9), while for grades 2/3 it was 88.2 s?1 (SD, 31.9) (p < 0.001). The hepcidin threshold for siderosis was > 30.2 ng/mL (sensitivity, 87%; specificity, 82%). Ferritin H and ferritin L subunits were expressed similarly in patients with NAFLD, regardless of siderosis. There were no significant differences in laboratory test results between the groups, including glucose parameters and liver function tests.ConclusionsMRI relaxometry and serum hepcidin accurately assessed mild iron overload in patients with dysmetabolic iron overload syndrome.  相似文献   
8.
Graefe's Archive for Clinical and Experimental Ophthalmology - Ferromagnetic foreign bodies (FFB) present during magnetic resonance imaging (MRI) explorations can lead to tissue injury due to...  相似文献   
9.
Cancer Causes & Control - Circulating estrogens are an established risk factor for postmenopausal breast cancer (BCa). We describe the distribution of urinary estrogens, their metabolites, and...  相似文献   
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