The Oxford Dodo. Part 2: from curiosity to icon and its role in displays,education and research

The Tradescant or Oxford Dodo has played an important role in exhibition and education throughout its 360-year history, and has been the subject of scientific research reflecting changing interests and techniques over this time. Due to confusion over its relationships, its placement in the classification systems continually changed, until the dissection in 1847 of the head and foot confirmed its columbid (pigeons and doves) affinities. Here, we describe the dissection of the head and foot and the Tradescant Dodo’s display history, from the late nineteenth century until the present day, and also its use in education. We discuss the importance of the Tradescant Dodo to Lewis Carroll, whose ‘Alice’s Adventures in Wonderland’ made the dodo aware to a worldwide audience. We further provide an overview of recent work including electron microscopic study of feathers, mDNA analysis, cytological investigation of the skin and measuring of the brain capacity, all of which have added to our knowledge of the evolution and ecology of this most extraordinary of birds. Research is ongoing; the Tradescant Dodo is presently subject to CT scanning and functional analysis. This is the second part of a two-part paper.     

Numerical simulation of arterial dissection during balloon angioplasty of atherosclerotic coronary arteries

Balloon angioplasty is a standard clinical treatment for symptomatic coronary artery disease. In this procedure, controlled damage is applied intraluminally to the wall of a stenotic artery. Dissection of the coronary artery is a commonly observed clinical complication of angioplasty; however, not all dissections can be detected angioscopically. This work focuses on studying the dissection mechanisms triggered during the early stages of angioplasty in an atherosclerotic coronary artery, addressing the problem by means of a parametric study based on a simplified finite element model and cohesive interface modeling. Our results emphasize the presence of several damage mechanisms, at different locations, that are triggered near the very beginning of the process and evolve competitively, depending on both geometry and material properties of the atherosclerotic vessel. Small-scale damage was evidenced, which would not be detectable by angiography or intravascular ultrasound, but could potentially be sufficient to stimulate smooth muscle cell activation, promoting late-onset complications such as restenosis.     

鼻内镜下低温等离子刀鼻后神经切断术与鼻内镜下鼻后神经切断术对中重度变应性鼻炎的近远期疗效及安全性分析

摘要 目的：探讨鼻内镜下低温等离子刀鼻后神经切断术与鼻内镜下鼻后神经切断术对中重度变应性鼻炎的近远期疗效及安全性。方法：选择2019年3月到2021年3月来我院诊治的变应性鼻炎患者90例,将其随机分为对照组与观察组,对照组中48例,观察组42例,对照组给予鼻内镜下鼻后神经切断术治疗,观察组给予鼻内镜下低温等离子刀鼻后神经切断术治疗。对比两组患者术前、术后3个月及术后1年的喷嚏、鼻塞、鼻痒、流涕临床症状评分、临床疗效、生活质量评分、血清血管活性肠肽5水平,对比两组并发症发生率。结果：术后3个月及术后1年,两组临床症状评分降低,且观察组较对照组低（P<0.05）;术后3个月,两组的临床症状评分低于同组间术后1年,但对比无差异（P>0.05）。术后3个月及术后1年,观察组的治疗有效率均较高（P<0.05）。术后3个月及术后1年,两组生活质量评分降低,且观察组较对照组低（P<0.05）;术后3个月,两组的生活质量评分高于同组间术后1年,但对比无差异（P>0.05）。术后3个月及术后1年,两组血清血管活性肠肽5水平降低,且观察组较对照组低（P<0.05）;术后3个月,两组的血清血管活性肠肽5水平低于同组间术后1年,但对比无差异（P>0.05）。观察组的并发症发生率较对照组低（P<0.05）。结论：与鼻内镜下鼻后神经切断术相比,鼻内镜下低温等离子刀鼻后神经切断术可提高中重度变应性鼻炎的近远期疗效,且安全性较好。     

A preferential site for sperm-egg fusion in mammals

The tendency of mammalian sperm-egg fusion to occur at a site away from the first polar body was investigated in a homologous (mouse oocytes and mouse spermatozoa) and in a heterologous model (hamster oocytes and mouse spermatozoa). Following micromanipulation of the zona pellucida either in proximity to or opposite the first polar body, in vitro fertilization was performed and subsequent differences in sperm-egg interaction were evaluated. Since spermatozoa from random-bred mice do not readily penetrate intact zonae pellucidae in vitro, it is likely that zona penetration occurred through the artificial holes in both models. The creation of a gap in the zona pellucida opposite the first polar body was associated with levels of sperm fusion that were significantly higher than those resulting from manipulation near the first polar body. Spermatozoa were rarely found to penetrate the hole completely, and in general few spermatozoa were observed in the pervitelline space. The proximity between pronuclei following sperm penetration was correlated with the position of the incision with respect to the polar body. The findings suggest that breaching the zona pellucida for microsurgical fertilization should be performed away from the microvillus-free area of the oocyte.     

Sarcolemmal calcium binding sites in heart: I. Molecular origin in “gas-dissected” sarcolemma

Summary Calcium in the myocardial cell is highly compartmentalized and a fast, an intermediate, a slow and a nonexchangeable calcium pool have been described. The fast pool contains 66% of the total cell exchangeable calcium in cultured neonatal rat heart cells with a t _1/2 of < 1.5 sec. Though the cellular origin of this fast pool is unknown, its rapidity and its displacement by La³⁺ most likely places it at the sarcolemma or at least in rapid equilibrium with the sarcolemma.We isolated the sarcolemma of cultured neonatal rat heart cells using the gas-dissection technique, which yields a pure sarcolemmal preparation in less than a second, thereby precluding membrane changes which might occur during conventional plasma membrane isolation. We determined the calcium binding characteristics of these membranes, using an on-line technique to monitor ⁴⁵Ca, which allows measurement of ⁴⁵Ca binding characteristics in the presence of unbound ⁴⁵Ca. Two classes of calcium binding sites were determined: (i) K _d of 13 m, capacity 7 nmol/mg and (ii) K _d of 1.1 mm, capacity of 84 nmol/mg. To assess the molecular origin of the sarcolemmal calcium binding we treated the membranes with a variety of enzymes. Protease or neuraminidase treatment did not cause large changes in these parameters. Simultaneous treatment with two different phospholipases C or the extraction of the lipids with isopropanol resulted in a dramatic loss of the low-affinity binding sites.These results, in association with previously defined sarcolemmal phospholipid distribution, places the low-affinity binding sites at the cytoplasmic leaflet. The physiological implication of this localization as it pertains to cellular calcium exchange is discussed.We thank Eloise Andrews-Farley for culturing of the neonatal cells. This study is supported by U.S. Public Health Service grants HL 28539-07 and 08, the Laubisch Fund, the Castera Foundation and the American Heart Association, Greater Los Angeles Affiliate.     

The endoscopist and malignant and non-malignant biliary obstruction

Patients with biliary strictures often represent a diagnostic and therapeutic challenge, due to the site and complexity of biliary obstruction and wide differential diagnosis. Multidisciplinary decision making is required to reach an accurate and timely diagnosis and to plan optimal care. Developments in endoscopic ultrasound and peroral cholangioscopy have advanced the diagnostic yield of biliary endoscopy, and novel optical imaging techniques are emerging. Endoscopic approaches to biliary drainage are preferred in most scenarios, and recent advances in therapeutic endoscopic ultrasound allow drainage where the previous alternatives were only percutaneous or surgical. Here we review recent advances in endoscopic practice for the diagnosis and management of biliary strictures. This article is part of a Special Issue entitled: Cholangiocytes in Health and Diseaseedited by Jesus Banales, Marco Marzioni and Peter Jansen.     

ERCP治疗急性胆源性胰腺炎86例胆汁细菌培养及药敏分析

目的了解急性胆源性胰腺炎（ABP）患者胆汁中主要致病菌的分布及其耐药情况,为临床治疗提供理论依据和治疗指导。方法选取2008年6月至2013年2月平顶山市第一人民医院消化内科收治的经内镜逆行胰胆管造影（EndoscopicRetrogradeCholangio—Pancreatography,ERCP）治疗的ABP患者86例,对术中抽取的胆汁标本行细菌培养和药敏试验,回顾性分析其临床结果。结果86例送检标本中,共检出76株病原菌,检出率为88．4％,胆汁感染的革兰阴性菌以大肠埃希菌为最多,革兰阳性菌以粪肠球菌最多;厌氧菌以感染脆弱类杆菌、产气荚膜梭菌等为主。结论ABP胆汁感染检出率高,致病菌种类与肠道细菌的种类基本一致,在胆汁细菌培养和药敏结果明确之前应尽量选用广谱的抗生素联合、足量用药;如药敏结果明确,则可根据治疗效果或药敏结果调整抗生素继续治疗,以提高疗效,避免浪费。     

构建基于患者个体化的Stanford B型主动脉夹层计算流体力学数值模拟分析模型（英文）

目的：探索简便、高效、精确的构建基于真实人体解剖形态结构的Stanford B型主动脉夹层计算流体力学数值模拟分析模型的方法。方法：利用Siemens Sensation Cardiac64层螺旋CT薄层扫描技术,基于1mm层厚获取6例Stanford B型主动脉夹层连续断层DICOM格式图像,导入Materialise MIMICS v12.11软件,界定目标区域后生成三维动脉模型,经网格优化处理去除低质量及相交面网格,保存结果输出,导入TGrid5.0软件,对主动脉面网格模型进行几何修复,使面网格扭曲率〈0.75,采用自由分网方式生成Stanford B型主动脉夹层计算流体力学分析体网格模型,并对所构建模型进行血流属性、流场边界等界定,初步验证模型的有效性。结果：通过初步计算求解,确定所构建的6例Stanford B型主动脉夹层计算流体力学分析模型分别包含1857030,1820501,1844181,1849651,1858246及1814914个四面体单元。结论：利用64层螺旋CT薄层扫描技术获取DICOM格式连续断层CT图像可快速、准确地构建Stanford B型主动脉夹层计算流体力学数值模拟分析模型,为进一步的计算流体力学分析奠定了良好的基础。