Animal Models of Middle Ear Cholesteatoma

Middle ear acquired cholesteatoma is a pathological condition associated with otitis media, which may be associated with temporal bone resorption, otorrhea and hearing loss, and occasionally various other complications. Cholesteatoma is characterized by the enhanced proliferation of epithelial cells with aberrant morphologic characteristics. Unfortunately, our understanding of the mechanism underlying its pathogenesis is limited. To investigate its pathogenesis, different animal models have been used. This paper provides a brief overview of the current status of research in the field of pathogenesis of middle ear acquired cholesteatoma, four types of animal models previously reported on, up-to-date cholesteatoma research using these animal models, our current studies of the local hybrid ear model, and the future prospect of new animal models of middle ear cholesteatoma

Effect of Reduction in Thickness and Rolling Conditions on Mechanical Properties and Microstructure of Rolled Mg-8Al-1Zn-1Ca Alloy

A cast Mg-8Al-1Zn-1Ca magnesium alloy was multipass hot rolled at different sample and roll temperatures. The effect of the rolling conditions and reduction in thickness on the microstructure and mechanical properties was investigated. The optimal combination of the ultimate tensile strength, 351 MPa, yield strength, 304 MPa, and ductility, 12.2%, was obtained with the 3 mm thick Mg-8Al-1Zn-1Ca rolled sheet, which was produced with a roll temperature of 80°C and sample temperature of 430°C. This rolling process resulted in the formation of a bimodal structure in the α-Mg matrix, which consequently led to good ductility and high strength, exclusively by the hot rolling process. The 3 mm thick rolled sheet exhibited fine (mean grain size of 2.7 μm) and coarse grain regions (mean grain size of 13.6 μm) with area fractions of 29% and 71%, respectively. In summary, the balance between the strength and ductility was enhanced by the grain refinement of the α-Mg matrix and by controlling the frequency and orientation of the grains

新聞の議題設定についての考察 －日韓外相会談報道にみる慰安婦問題－

本稿は、2015年12月28日に行われた「日韓外相会談」に関する新聞報道（2015年12月24日から2016年1月23日の朝日新聞および読売新聞）の分析から、「慰安婦問題」に関する新聞の議題設定の状況を明らかにすることを試みたものである。分析の結果、「日韓外相会談」に関する新聞報道は、この会談が慰安婦問題を「解決」に向かわせる出来事として伝えたこと、慰安婦問題は韓国、米国、北朝鮮など他国との関係においても言及されることなど、いくつかの傾向を導出した

3Dマッピングシステムを用いた両心房Stimulus-V mapによる順行性速伝導路入口部の解剖学的位置並び特徴の検討

Purpose Previous studies examined the right atrial (RA) input site of the antegrade fast pathway (AFp) (AFpI). However, the left atrial (LA) input to the atrioventricular (AV) node has not been extensively evaluated. In this study, we created three-dimensional (3-D) bi-atrial stimulus-ventricle (St-V) maps and analyzed the input site and characteristics of the AFp in both the RA and LA. Methods Forty-four patients diagnosed with atrial fibrillation or WPW syndrome were included in this study. Three-dimensional bi-atrial St-V mapping was performed using an electroanatomical mapping system. Sites exhibiting the minimal St-V interval (MinSt-V) were defined as AFpIs and were classified into seven segments, four in the RA (F, S, M, and I) and three in the LA (M1, M2, and M3). By combining the MinSt-V in the RA and LA, the AFpIs were classified into three types: RA, LA, and bi-atrial (BA) types. The clinical and electrophysiological characteristics were compared. Results AFpIs were most frequently observed at site S in the RA (34%) and M2 in the LA (50%), and the BA type was the most common (57%). AFpIs in the LA were recognized in 75% of the patients. There were no clinical or electrophysiological indicators for predicting AFpI sites. Conclusions Three-dimensional bi-atrial St-V maps could classify AFpIs in both the RA and LA. AFpIs in the LA were frequently recognized. There were no significant clinical or electrophysiological indicators for predicting AFpI sites, and 3-D bi-atrial St-V mapping was the only method to reveal the precise AFp input site

Effects of Esaxerenone on Diabetes-Induced Endothelial Dysfunction

Aims: Pharmacological blockade of mineralocorticoid receptors (MRs) is a potential therapeutic approach to reduce cardiovascular complications since MRs play a crucial role in cardiovascular regulation. Recent studies suggest that MR antagonists affect several extrarenal tissues, including vessel function. We investigated the effect of a novel nonsteroidal selective MR blocker, esaxerenone, on diabetes-induced vascular dysfunction. Methods: Diabetes was induced by a single dose of streptozotocin in 8-week-old male C57BL/6 mice. Esaxerenone (3 mg/kg/day) or a vehicle was administered by gavage to diabetic mice for 3 weeks. Metabolic parameters, plasma aldosterone levels, and parameters related to renal function were measured. Endothelium-dependent or -independent vascular responses of the aortic segments were analyzed with acetylcholine or sodium nitroprusside, respectively. Human umbilical vein endothelial cells (HUVECs) were used for the in vitro study. Results: Induction of diabetes elevated plasma aldosterone level (P＜0.05) and impaired endothelium-dependent vascular relaxation (P＜0.05). The administration of esaxerenone ameliorated the endothelial dysfunction (P＜0.01) without the alteration of metabolic parameters, blood pressure, and renal function. Esaxerenone improved the eNOSSer1177 phosphorylation in the aorta obtained from diabetic mice (P＜0.05) compared with that in the vehicle-treated group. Furthermore, a major MR agonist, aldosterone, decreased eNOSSer1177 phosphorylation and increased eNOSThr495 phosphorylation in HUVECs, which recovered with esaxerenone. Esaxerenone ameliorated the endothelium-dependent vascular relaxation caused by aldosterone in the aortic segments obtained from C57BL/6 mice (P＜0.001). Conclusion: Esaxerenone attenuates the development of diabetes-induced endothelial dysfunction in mice. These results suggest that esaxerenone has potential vascular protective effects in individuals with diabetes

センタク ニヨル オリモノ ノ シュウシュク ト センザイ ノ エイキョウ

手洗いと洗濯機のドライコースで,それぞれ羊毛,絹およびレーヨンの織物を洗濯し,洗濯後の収縮率および厚さ変化と,洗濯回数および洗剤の種類などとの関係について実験を行った。その結果を参考にして収縮に対する洗濯回数,洗濯方法および洗剤などの影響,洗濯による織物の収縮機構および収縮の異方性について考察し,次のような結果を得た。1.本実験に用いた織物(羊毛,絹,レーヨン)はいずれも1回の洗濯でかなり収縮し,羊毛およびレーヨンでは2回目以降も収縮率が増加する。絹の繊維は細く,水による膨潤も比較的小さいため,2回目以降収縮率はほとんど増加しない。2.手洗いでは,洗濯機に比べていずれの試料も,3回目までの収縮率が小さい。手洗いでは外力はほとんど加えられていないが,洗濯機では試料にわずかな振動が加えられているためであろう。3.洗濯による収縮は,水のみで洗濯しても,水に洗剤を加えて洗濯した場合とあまり変わらない。洗濯による織物の収縮は大部分水の影響によるものである。ただし,羊毛の表面は撥水性であり,洗剤の添加により濡れやすくなるので,収縮率および厚さ変化率が増加する傾向がある。4.各試料とも収縮率が大きい方向の糸のクリンプが大きい。また,たて方向の収縮が大きい試料では,収縮によりたて曲がり構造に近づき,よこ方向の収縮が大きい試料では,よこ曲がり構造に近づくため,織物の厚さが増加する。5.レーヨン織物のたて方向の厚さ変化率は収縮率と同程度の値であり,繊維自体の緩和収縮では説明できない。また,水のみの厚さ変化率と収縮率との関係は,原点を通る直線で近似できる。従ってレーヨンの収縮は,主として繊維の膨潤に基づく糸の屈曲状態(クリンプ)の変化によるものと考えられる

Clinical clerkship students’ preferences and satisfaction regarding online lectures during the COVID-19 pandemic

Background: The COVID-19 pandemic has caused an unprecedented disruption in medical education. Students and lecturers had to adapt to online education. The current study aimed to investigate the level of satisfaction and future preference for online lectures among clinical clerkship students and elucidated the factors that affect these outcomes. Methods: We selected a sample of 114 medical students undergoing clinical clerkship during the COVID-19 pandemic. We conducted onsite lectures before the pandemic and online lectures after the outbreak. A survey was conducted, and the sample included students and 17 lecturers. The average scores of total satisfaction and future preference related to online lectures were computed. Results: Students’ scores on total satisfaction with online lectures and their future preference were higher than those for onsite lectures. Scores on the ease of debating dimension were low and those on accessibility of lectures in online lectures were higher than those in onsite lectures. There was no difference between the two groups in the scores on the comprehensibility and ease of asking questions dimensions. Results of the multiple regression analysis revealed that accessibility determined total satisfaction, and future preference was determined by comprehensibility as well as accessibility. Contrary to students’ future preferences, lecturers favored onsite lectures to online ones. Conclusion: Online lectures are an acceptable mode of teaching during the COVID-19 pandemic for students undergoing clinical clerkship. Online lectures are expected to become more pervasive to avoid the spread of COVID-19

Expression of human mutant cyclin dependent kinase 4, Cyclin D and telomerase extends the life span but does not immortalize fibroblasts derived from loggerhead sea turtle (Caretta caretta)

Conservation of the genetic resources of endangered animals is crucial for future generations. The loggerhead sea turtle (Caretta caretta) is a critically endangered species, because of human hunting, hybridisation with other sea turtle species, and infectious diseases. In the present study, we established primary fibroblast cell lines from the loggerhead sea turtle, and showed its species specific chromosome number is 2n = 56, which is identical to that of the hawksbill and olive ridley sea turtles. We first showed that intensive hybridization among multiple sea turtle species caused due to the identical chromosome number, which allows existence of stable hybridization among the multiple sea turtle species. Expressions of human-derived mutant Cyclin-dependent kinase 4 (CDK4) and Cyclin D dramatically extended the cell culture period, when it was compared with the cell culture period of wild type cells. The recombinant fibroblast cell lines maintained the normal chromosome condition and morphology, indicating that, at the G1/S phase, the machinery to control the cellular proliferation is evolutionally conserved among various vertebrates. To our knowledge, this study is the first to demonstrate the functional conservation to overcome the negative feedback system to limit the turn over of the cell cycle between mammalian and reptiles. Our cell culture method will enable the sharing of cells from critically endangered animals as research materials