Morphologic Alterations in Sheep After Implantation of the Akutsu Total Artificial Heart

The present report describes morphologic alterations produced in sheep after implantation of a four-chambered total artificial heart. Two groups of sheep were studied. The first group was given no special antishock therapy and had an average survival time of 25.8 hours. Major morphologic changes produced in the first group were focal infarction and massive hemorrhage of the large and small bowel, ascites, severely altered lungs and multiple infarcts in the kidneys. The second group of sheep was given antishock therapy and showed an average survival time of 35.4 hours. Severe morphologic alterations in this group were generally absent in all organs except the lungs, which showed varying degrees of congestion, hemorrhage, edema, pneumonitis and atelectasis. Death in both of the above groups was due to development of irreversible hypotension and respiratory failure.     

人工心脏电动叶轮血泵的动物实验研究

作者报道了左心室辅助及双心室辅助叶轮血泵的急性实验和存活实验。证明离心型人工心脏在可植入性，血液相容性及机械可靠性等方面具有一定优势。并讨论了叶轮血泵的密封问题，从而为叶轮血泵的进一步动物实验，为过渡至急性心脏梗塞后心源性休克和心脏手术后的短期辅助为目标的临床应用准备条件，对于心脏移植前心室辅助超过２周甚至长达数月的叶轮血泵尚需作进一步的研究。     

Application of Adaptive Starling-Like Controller to Total Artificial Heart Using Dual Rotary Blood Pumps

The successful clinical applicability of rotary left ventricular assist devices (LVADs) has led to research interest in devising a total artificial heart (TAH) using two rotary blood pumps (RBPs). The major challenge when using two separately controlled LVADs for TAH support is the difficulty in maintaining the balance between pulmonary and systemic blood flows. In this study, a starling-like controller (SLC) hybridized with an adaptive mechanism was developed for a dual rotary LVAD TAH. The incorporation of the adaptive mechanism was intended not only to minimize the risk of pulmonary congestion and atrial suction but also to match cardiac demand. A comparative assessment was performed between the proposed adaptive starling-like controller (A-SLC) and a conventional SLC as well as a constant speed controller. The performance of all controllers was evaluated by subjecting them to three simulated scenarios [rest, exercise, head up tilt (HUT)] using a mock circulation loop. The overall results showed that A-SLC was superior in matching pump flow to cardiac demand without causing hemodynamic instabilities. In contrast, improper flow regulation by the SLC resulted in pulmonary congestion during exercise. From resting supine to HUT, overpumping of the RBPs at fixed speed (FS) caused atrial suction, whereas implementation of SLC resulted in insufficient flow. The comparative study signified the potential of the proposed A-SLC for future TAH implementation particularly among outpatients, who are susceptible to variety of clinical scenarios.     

人造机械瓣心音的分析研究

在一些致命性心脏病的诊断中,心音听诊是最有效也是应用得最成功的手段之一.鉴于目前机械瓣的使用非常普遍,研究简单有效的机械瓣病变判别方法对于临床诊断来讲具有重要意义.运用希尔波特-黄变换(HHT),针对不同的机械瓣心音进行分析,并设计一种基于Hilbert边界谱特征的提取方法,结合线性判别分析(LDA),对不同的机械瓣心音进行分类.同时,与基于局部最优基特征的分类器分类结果进行比较.分析结果表明,机械瓣心音的各阶Hilbert边界谱具有非常明显不同的分布,基于HHT的分类器识别率达到了97.3％,较基于局部最优基特征分类器的识别率(91.3％)更高.对于人造机械瓣心音而言,HHT是一种有效的分析处理手段.     

Cardiopulmonary exercise testing responses to different external portable drivers in a patient with a CardioWest Total Artificial Heart

Management of patients treated with CardioWest Total Artificial Heart (CW-TAH) as a bridge to heart transplantation (HTx) is complicated by difficulties in determining the optimal timing of transplantation. We present a case of a 53-year-old man supported as an outpatient with a CW-TAH, whose condition deteriorated following exchange of the portable driver. The patient was followed-up with serial cardiopulmonary exercise testing (CPET) which demonstrated a fall of peak VO₂ to below 12 ml/kg/min following driver substitution, and the patient was subsequently treated with urgent orthotopic HTx. This case highlights the potential utility of CPET as a means for monitoring and indicating timing of HTx in patients with CW-TAH, as well as the potential for clinical deterioration following portable driver substitution.     

后置导轮对人工轴流心脏泵的影响分析

后置导轮在人工轴流心脏泵工作过程中具有至关重要的作用,为了研究其对心脏泵的影响,利用计算流体力学(CFD)的方法,详细分析了后置导轮对人工轴流心脏泵工作情况的影响。通过对轴流心脏泵内整个流场的数值模拟,讨论了引入后置导轮后,轴流心脏泵的压强增量、效率、工作情况以及流体受力等重要参数的变化。计算结果表明:引入合适的后置导轮能够改善流场分布,限制出流的速度方向,提供足够的静压增量,有利于传输血液,同时基本保持了泵的效率不降低。因此,在人工轴流心脏泵设计过程中引入后置导轮是必要的,但需要对后置导轮的参数进行严格的分析。     

New Artificial Heart Integrates Parts Taken from Cow

In a new step forward in artificial heart technology, French medical company has developed a new artificial heart that is part bovine and part machine. The idea behind this design was to use actual bovine tissue for parts of the artificial heart that would come in contact with a wearer＇s blood, thus leading to greater biocompatibility. Their design consists of two chambers separated by a membrane taken from a cow＇s heart. One chamber houses the wearer＇s actual blood and the other chamber houses hydraulic fluid that is driven by a motor to exert force on the membrane, thereby causing flow in the chamber housing blood, leading to circulation. In addition to the dividing membrane being made of bovine tissue, the heart valves are also made of components taken from cows. The bovine components used to make the valve not only serves the purpose of greater biocompatibility, but is also equipped with embedded sensors to measure the pressure on them. Such measurements could be used to monitor exertion and adiust ＂hear rate＂ as needed.     

人工生物瓣膜研究进展

人工心脏瓣膜置换术是目前治疗末期心脏瓣膜疾病的有效手段。临床上广泛使用的人工生物瓣虽有血流近似生理流型、不易形成血栓等优点,但却有容易钙化、撕裂、有残留免疫原性及缓慢释放交联剂所带来的细胞毒性等缺点。该文综述了目前为克服这些缺点而进行的相关研究进展。     

State-of-the-art nanopathological diagnostics

The nanopathological diagnostics (ND) is an ultra-specialized branch of pathological anatomy aimed to identify the nanoparticles of metallic, semimetallic, or nonmetallic elements in the inorganic particulate matter present inside pathological tissues, even on the nanometer scale. ND exploits an environmental scanning electron microscope, connected to an X-ray microprobe mounted on an energy-dispersive spectrometer. The searching of nanoparticles can be performed on paraffin-embedded material, omitting emissions of black overlay and plating procedures. The technique is highly sensitive and specific, reproducible and rapid, covering an entire operating cycle in few hours. Nowadays, ND finds many applications: (I) intratumor detection of heavy metals and endocrine metal disruptors; (II) identification of pathogenic nanoparticles in medical or veterinary drugs and devices, cosmetics, household products, and foodstuffs; (III) differential diagnosis of sarcoid-type granulomas (berylliosis, baritosis) and foreign body granulomas (prosthetic, iatrogenic); (IV) attestation of occupational disease correlating the datum with the occupational risk (anthracosis, asbestosis, bauxite fibrosis, byssinosis, chalicosis, siderosis, silicosis, stannosis, talcosis); and (V) forensic investigations to ascertain a causal link between disease and environmental, military, or work exposure. In addition to filling a knowledge gap, ND offers to the pathologist a current research field, with particular reference to the impact of occupational and environmental pollution on the human health and cancer.     

State-of-the-art medical pH probes

This article deals with the development of reusable peroral, transnasal, and endoscopic pH probes, and it looks into the operational features of pH probes equipped with silver-chloride distal and surface reference electrodes. The results obtained revealed that pH probes with a surface reference electrode offer a number of advantages over pH probes with a distal reference electrode.     

人工心脏传子系统数学建模与仿真

目的研究用于左心室辅助装置(LVAD)的无磨损的血泵转子系统,为第三代人工心脏即轴流血泵柔性转子建立数学模型并进行控制仿真分析.方法将血泵转子悬浮于主动式磁轴承(AMB)系统中,利用线性化方法建立系统简单的线性数学模型,利用状态变量反馈(SVFB)方法、全次元观测器(observer)设计和线性二次控制器(LQR)对系统进行控制仿真.结果与讨论人工心脏血泵转子系统对干扰的稳定延迟时间为350ms,稳态误差接近0,无超调现象,满足血泵转子系统设计要求.     

人工心瓣用热解炭断裂韧性研究及断口形貌分析

人工心瓣中常用材料主要是包覆在石墨基体上的热解炭。为研究人工心瓣用热解炭材料断裂韧性,采用MTS电动力学测试系统,对石墨、纯热解炭及不同厚度热解炭包覆石墨复合材料4种DC(T)圆盘样品进行紧凑拉伸实验,利用实验所得数据绘制载荷-位移(P-V)曲线,根据ASTM标准E399规定的方法确定临界载荷值以及计算断裂韧性值,并对样品断口形貌进行显微观察。结果表明:两种热解炭包覆石墨复合材料断裂韧性值大于纯热解炭以及石墨的相应值,石墨断裂韧性值大于纯热解炭断裂韧性值;在热解炭包覆石墨复合材料中,涂层与基体厚度比值大的对应断裂韧性值反而小;显微观察热解炭断口较为平整,石墨断口较为粗糙,且热解炭及石墨在裂纹扩展区以及过载断裂区的断口形貌基本上是一致的。     

State-of-the-art pharmacotherapy of juvenile arthritis

The review of state-of-the-art stage of pharmacotherapy of juvenile arthritis is represented. Main principles and features of the use of antirheumatic remedies in children are given with the accent to age limitations. Detailed characteristic used drugs and treatment schemes and also recommendations for prevention and monitoring of collateral reactions are given. Special attention is devoted to differential approach to the therapy of juvenile arthritis various variants: systemic, polyarticular and oligoarticular. Schematic algorithms of therapeutical tactics are represented.     

表面改性人工机械心脏瓣膜的动物体内实验研究

通过人工瓣膜临床前羊慢性存活实验,探讨新型国产表面改性人工心脏瓣膜的抗凝血性能和综合性能。在19例羊心脏内植入新型TiO2-x/TiN薄膜材料制成的国产双叶人工瓣膜,与植入热解碳制成的St Jude双叶瓣进行对比,分析凝血指标、血流动力学测定、心脏超声检查和长期生存动物形态学及病理组织学检查,对该瓣膜的综合性能做临床前动物体内评价。成活15例,4例死亡,其中对照组8例、实验组7例,最长存活9个月且是实验组。两组凝血指标在围术期及术后24h内相似,无显著性差异(P>0.05);对照组术后1～20周血凝血酶时间均较实验组高,有显著性差异(P<0.05),考虑与华法林抗凝治疗有关,而实验组在术后1周以后恢复术前水平。两组血流动力学围术期变化相似,心脏超声检查及术后半年尸检示两组各瓣膜活动好,均未见血形成,无赘生物,各主要脏器均无栓塞等异常改变。该新型国产人工瓣膜与进口机械瓣有相似的血流动力学功能,获得了满意的长期生存效果,且抗凝血性能明显优于进口机械瓣。