Computational model for simulation of vascular adaptation following vascular access surgery in haemodialysis patients

An important number of surgical procedures for creation of vascular access (VA) in haemodialysis patients still results in non-adequate increase in blood flow (non-maturation). The rise in blood flow in arteriovenous shunts depends on vascular remodelling. Computational tools to predict the outcome of VA surgery would be important in this clinical context. The aim of our investigation was then to develop a 0D/1D computational model of arm vasculature able to simulate vessel wall remodelling and related changes in blood flow. We assumed that blood vessel remodelling is driven by peak wall shear stress. The model was calibrated with previously reported values of radial artery diameter and blood flow after end-to-end distal fistula creation. Good agreement was obtained between predicted changes in VA flow and in arterial diameter after surgery and corresponding measured values. The use of this computational model may allow accurate vascular surgery planning and ameliorate VA surgery outcomes.     

The C-seal: A Biofragmentable Drain Protecting the Stapled Colorectal Anastomosis from Leakage

Colorectal anastomotic leakage (AL) is a serious complication in colorectal surgery leading to high morbidity and mortality rates¹. The incidence of AL varies between 2.5 and 20% ^2-5. Over the years, many strategies aimed at lowering the incidence of anastomotic leakage have been examined^{6, 7}.The cause of AL is probably multifactorial. Etiological factors include insufficient arterial blood supply, tension on the anastomosis, hematoma and/or infection at the anastomotic site, and co-morbid factors of the patient as diabetes and atherosclerosis⁸. Furthermore, some anastomoses may be insufficient from the start due to technical failure.Currently a new device is developed in our institute aimed at protecting the colorectal anastomosis and lowering the incidence of AL. This so called C-seal is a biofragmentable drain, which is stapled to the anastomosis with the circular stapler. It covers the luminal side of the colorectal anastomosis thereby preventing leakage.The C-seal is a thin-walled tube-like drain, with an approximate diameter of 4 cm and an approximate length of 25 cm (figure 1). It is a tubular device composed of biodegradable polyurethane. Two flaps with adhesive tape are found at one end of the tube. These flaps are used to attach the C-seal to the anvil of the circular stapler, so that after the anastomosis is made the C-seal can be pulled through the anus. The C-seal remains in situ for at least 10 days. Thereafter it will lose strength and will degrade to be secreted from the body together with the gastrointestinal natural contents.The C-seal does not prevent the formation of dehiscences. However, it prevents extravasation of faeces into the peritoneal cavity. This means that a gap at the anastomotic site does not lead to leakage.Currently, a phase II study testing the C-seal in 35 patients undergoing (colo-)rectal resection with stapled anastomosis is recruiting. The C-seal can be used in both open procedures as well as laparoscopic procedures. The C-seal is only applied in stapled anastomoses within 15cm from the anal verge. In the video, application of the C-seal is shown in an open extended sigmoid resection in a patient suffering from diverticular disease with a stenotic colon.     

虫害诱导黑杨对分月扇舟蛾生长发育的影响

在实验室条件下,通过人工饲养研究了虫害处理的69杨和895杨对分月扇舟蛾Clostera anastomosis幼虫、蛹及成虫的生长发育的影响。结果表明:虫害处理的叶片对分月扇舟蛾幼虫表现为驱避作用;取食虫害处理的叶片,使得幼虫的发育历期延长,死亡率增加,对食物的利用和转化效率下降;蛹重减轻,蛹期延长;成虫的羽化率降低,产卵量减少。说明昆虫取食危害能够诱导杨树对分月扇舟蛾产生抗虫性。     

激光血管吻合技术研究进展

临床血管吻合常使用缝合、吻合夹或吻合针。缝合法手术成本低、成功率高并且适合各种尺寸的血管,因此使用最为广泛。上述常用方法都会对血管产生损伤,而且手术工作量大。激光血管吻合术提供了一种微创的血管吻合方法。其潜在的优点包括保证吻合口的密闭,增加伤口吻合强度。同时减少手术操作时间、降低感染和流血的可能性,并且术后疤痕少,带有一定美容效果。因此,与传统缝合法等相区别的激光血管吻合技术作为一种新颖的技术受到极大的关注。然而,激光血管吻合术未成为一种临床常用的血管吻合方法,其主要原因有：直接激光照射可对组织产生过度热损伤、组织精准对齐技术难度大、手术成功与否的终点判断比较模糊以及重复性较差等。近年来,随着激光器技术以及材料技术的发展,激光血管吻合术正在逐步走向成熟,有可能作为一种应急性的、微创的血管吻合方法而应用于I临床。     

降落伞式缝合在肠道吻合术中的应用

目的:通过胆肠吻合缝合技术的改进,减少并发症的发生。方法:对52例肠道吻合手术采用降落伞式缝合。结果:降落伞式胆肠吻合时间平均20 min,明显缩短了手术时间,全部病例均未出现胆肠吻合漏,无死亡病例。结论:降落伞式胆肠吻合术具有操作简便、省时、并发症少等特点。     

Vegetative compatibility groups and sexual reproduction among Spanish Monilinia fructicola isolates obtained from peach and nectarine orchards,but not Monilinia laxa

The frequency of occurrence of Monilinia fructicola in the Ebro Valley, Spain has increased since its first appearance in 2006, and M. fructicola has displaced Monilinia laxa, the native species which is the main cause of brown rot in peaches in this valley. In order to determine the characteristics that may be related to the displacement, we studied the capacity to generate new genotypic combinations of M. fructicola under laboratory conditions. The morphology and parasitic ability from ten field isolates of M. fructicola and M. laxa collected from three different orchards in the valley, and sampling from five different lesions were studied. Nitrate-non-utilising (nit) mutants were generated in order to test the isolates for vegetative compatibility which was done by assessing their colony growth when cultured singly or in pairs on media that contained different nitrogen sources. For the M. fructicola isolates, five vegetative compatibility groups (VCGs) were identified using the nit mutants and six VCGs were identified when they were grown on potato dextrose agar dishes. In all instances, the vegetatively compatible M. fructicola isolates came mainly from the same orchard. Only one VCG displays the same morphological and competition characteristics. No VCGs were identified among the M. laxa isolates. We did not find any apothecia of M. laxa and M. fructicola isolates in the soil of the three orchards, but we were able to produce apothecia of M. fructicola in the laboratory. Our finding of sexual reproduction and VCGs in the M. fructicola isolates suggests that the genetic variability of M. fructicola could be maintained by sexual and/or parasexual recombination.     

中国东北地区玉米纹枯病菌的融合群鉴定

自东北三省采集玉米纹枯病标本300余份,分离获得286个丝核菌菌株。融合群测定及5.8S rDNA-ITS区序列分析结果表明,这些菌株分别属于多核丝核菌的AG1-IA、AG1-IB、AG1-IC、AG4-HG-I、AG4-HG-III、AG-5、WAG-Z群及双核丝核菌的AG-Ba群。其中AG1-IA是优势致病群,占分离菌株总数的38.46%,其次是WAG-Z和AG-5群,分别占26.92%及24.83%。AG4-HG-III群菌株是国内首次从罹病玉米植株上分离得到。自各融合群中选取代表性的菌株进行5.8     

美洲黑杨不同无性系对分月扇舟蛾幼虫的抗性及相关机理

为了选育出在生产上具有推广价值的美洲黑杨Populus deltoides优良抗虫品系,本研究以分月扇舟蛾Clostera anastomosis 3龄幼虫为材料,以I-72杨为对照评价和分析了18个美洲黑杨无性系在实验室条件（28±1℃,RH 70%,16L∶8D）下的抗虫性,通过选择性和非选择性取食实验筛选出了11个具有较强抗性的无性系; 测定了美洲黑杨主要营养物质和次生代谢物质含量,研究了不同无性系对分月扇舟蛾体内保护酶和消化酶活性及对该虫生长发育和食物利用的影响。结果表明：美洲黑杨不同无性系抗性的大小与它们叶片中总酚含量呈明显正相关趋势; 抗性水平不同的无性系对分月扇舟蛾幼虫的生长发育和食物利用有不同的影响,表现在幼虫体重、每日体重增加量、相对生长率、近似消化率、食物利用率和食物转化率等主要生长发育指标的变化上,同时对分月扇舟蛾幼虫取食量和排粪量亦有不同的影响。结果说明,分月扇舟蛾对次生代谢物质的反应更为敏感,抗性无性系对分月扇舟蛾幼虫体内SOD和CAT酶活性有明显的激活作用。