经导管瓣膜瓣中瓣模式下流体力学性能体外测试及评价

目的 随着生物瓣膜毁损病例的增加,越来越多的经导管瓣膜作为瓣中瓣被应用于二次瓣膜置换手术,但其流体力学性能鲜有报道.本文将经导管瓣膜安装在生物瓣膜内形成瓣中瓣结构,并对其流体力学性能进行体外测试及评价.方法 将经导管瓣膜(23 mm、27 mm、29 mm)分别安装在对应规格生物瓣膜(23 mm、27 mm、29 mm)中形成瓣中瓣,进行稳态前向流实验、稳态反向泄漏实验、脉动流实验,对其流体力学性能进行评价,并与同规格生物瓣膜流体力学性能进行对比.结果 稳态前向流实验中,同一规格的经导管瓣中瓣跨瓣压差随着前向流量的增大而增大.稳态反向泄漏实验中,同一规格的经导管瓣中瓣泄漏量随着反向压力的增大而增大.脉动流实验中,经导管瓣中瓣和生物瓣膜的平均跨瓣压差、返流百分比和有效瓣口面积变化趋势相同.对于同一规格的经导管瓣中瓣和生物瓣膜,随着心输出量的增加,跨瓣压差增大,返流百分比减小,有效瓣口面积增大;在同一心输出量下,随着经导管瓣中瓣和生物瓣膜规格的增大,跨瓣压差减小,返流百分比增大,有效瓣口面积增大.结论 经导管瓣中瓣体外脉动流性能指标满足YY/T1449.3—2016标准中经导管瓣膜的性能要求,且其脉动流性能与同规格生物瓣膜相比无明显差异.该经导管瓣中瓣具有良好的血流动力学性能.     

介入瓣膜瓣中瓣模式下耐久性能测试及评价

目的随着之前植入外科人工生物心脏瓣膜患者瓣膜毁损的病例增加,介入瓣膜瓣中瓣越来越多地被用于临床。由于其临床应用时间不长,目前没有长期临床数据可以参考,故实验采用体外加速方法,对一种介入瓣膜瓣中瓣耐久性能进行测试及评价。方法将23 mm、27 mm、29 mm 3个规格(牛心包材质)介入瓣膜作为瓣中瓣分别安装在23 mm、27 mm、29 mm对应规格外科生物心脏瓣膜中,通过预扩达到相同的内径后进行体外加速疲劳耐久性能测试,每5 000万次对其脉动流性能进行测试。2.0亿次疲劳测试后,对瓣叶进行热力学分析、双光子共聚焦显微镜下观察瓣叶胶原纤维结构。结果经过2.0亿次耐久性能测试,介入瓣膜瓣中瓣平均跨瓣压差无显著变化[23 mm:1.92～1.98 kPa(14.4～14.9 mmHg);27 mm:0.92～1.64 kPa(6.9～12.3 mmHg);29 mm:0.72～1.02 kPa(5.4～7.4 mmHg)],有效瓣口面积基本一致(23 mm:1.45～1.66 cm2;27 mm:1.88～2.17 cm2;29 mm:2.24～2.54 cm2),反流百分比减小(23 ...     

一种新型抗钙化处理的人工生物瓣膜流体力学性能

目的 评价一种新型生物瓣膜的体外流体力学性能,并与传统生物瓣膜及机械瓣膜进行比较.方法 将测试瓣膜分成三组:新型生物瓣组(GA SOB处理牛心包瓣),传统生物瓣组(单纯GA处理牛心包瓣),机械瓣组(双叶瓣),每组分别选21号、25号、29号三种型号,采用清华大学TH-1200脉动流测试仪,按照ISO5840瓣膜检测标准进行流体性能检测,包括跨瓣压差、返流量、返流百分比及有效开口面积,并进行组间的分析、比较.结果 新型生物瓣膜的前向流跨瓣压差较传统生物瓣小17%～30%,较机械瓣小23%～50%;新型生物瓣的有效开口面积较传统生物瓣和机械瓣分别大13%～37%和36%～50%;新型生物瓣的返流量较传统生物瓣大1.2～2.0 mL,约3%～6%;较机械瓣小0.9～2.8mL,约1.3%～5%.结论 新型人工生物瓣膜具有良好的血流动力学性能.     

含有镍钛合金丝的PET纺织瓣膜有限元分析及体外流体力学测试

目的 利用有限元方法分析径向织入镍钛金属丝的涤纶(polyethylene terephthalate, PET)基纺织瓣膜力学性能,结合体外血流动力学测试,分析金属丝数量和分布形式对PET瓣膜流体动力学性能的影响。方法 使用建模软件构建在径向方向上具有不同数量和分布的金属丝PET瓣膜和无金属丝PET瓣膜三维几何模型;根据文献和实验数据给定PET瓣膜和金属丝的材料属性;使用体外脉动流实验得到PET瓣膜的跨瓣压差曲线作为边界条件;利用有限元分析软件研究瓣膜在心动周期内的应力分布;通过体外脉动流实验评估金属丝瓣膜的流体力学性能。结果 有限元分析结果表明,径向织入镍钛金属丝可以增强对PET纺织瓣膜的支撑作用,金属丝均匀分布的瓣膜在瓣叶腹部区域的支撑力及作用区域随着金属丝数量增加而增大,金属丝分布在两侧位置的情况类似。金属丝的织入一定程度上改善PET瓣膜上的应力集中。脉动流实验结果表明,织入金属丝PET瓣膜开闭形态的稳定性、有效开口面积、反流分数和跨瓣压差等指标均优于无金属丝的纯PET瓣膜。结论 在PET纺织瓣膜的径向方向织入金属丝可以有效减少心动周期内PET纺织瓣膜上的应力集中,降低PET纺...     

一种新型介入瓣膜脉动流性能的初步研究

本文对一种国产新型介入瓣膜(HVPMIT)的体外脉动流性能进行了初步评价,并就该方法对HVPMIT的适用性进行了初步探索。试验中以国产HVPMIT为试验样品、进口的常规生物瓣为对照样品,根据ISO5840-2005和GB 12279-2008标准列出的方法,采用人工心脏瓣膜脉动流测试仪测定了试样的脉动流参数(包括平均跨瓣压差、返流百分比和有效开口面积)。结果显示,在模拟心输出量为5L/min时,HVPMIT的返流百分比高达13%,显著高于对照瓣,显示其发生了瓣周漏。进一步分析可以发现因为HVPMIT在植入体内时不需缝合,因此在HVPMIT支架外侧没有缝合环。当将HVPMIT夹持在试验仪器上时夹持垫片和HVPMIT支架间有明显缝隙,所以导致瓣周漏的发生。这说明,HVPMIT在外形、结构、在心脏上的固定方式、临床的手术方法等方面和传统的心脏瓣膜有明显的区别。必须根据其自身的特点,设计和建立适用的检测方法来科学客观地评价HVPMIT的性能。     

婴幼儿罗叶泵聚氨酯瓣膜的制作及功能测试

背景：现有成人罗叶泵使用机械瓣,但机械瓣膜的尺寸较大,对血液破坏较大,不适于婴幼儿心室辅助泵,故设计和制作尺寸小、血栓形成低的高分子瓣膜是目前研究的热点。 目的：设计和制作20 mL婴幼儿罗叶泵的瓣膜,并进行基本功能测试和疲劳测试 方法：通过MASTERCAM软件设计瓣膜尺寸和形状,通过制作瓣膜模具和注塑获得聚氨酯瓣膜;根据ISO5840的要求测试聚氨酯瓣膜的静止泄露、跨瓣压差和耐疲劳性能。 结果与结论：制作了聚氨酯三叶瓣膜,但注塑失败率较高;所制作的三叶瓣膜的基本功能基本符合ISO 5840的要求;聚氨酯瓣膜在连续运行1.0×107次后,20 mL罗叶泵的搏出量的变化率为5.2%。两个聚氨酯瓣膜保持完整,瓣叶无变化。说明设计并成功制作了聚氨酯三叶瓣膜;所制备的聚氨酯瓣膜能满足20 mL罗叶泵的需要,已具备了临床试验的能力。     

同种主动脉瓣作为人工心瓣流体动力学特性测试标准参比…

本研究采用类似于临床原位移植方法，将同种动脉瓣固定在ＰＳ－１型装置的主动脉瓣位上。脉动流测试结果表明：此无结构和材料缺陷心瓣表现出理想心瓣特性：小而相对固定的瓣膜关闭容积，无舒张期泄漏，瓣环可扩张，在相对于正常成人的模拟心率和心输出量时，有效开口面积不小于其对应的肺动脉瓣环径解剖值。这是用此装置测试人工心瓣血流动力学性能的绝对标准。与在体正常值比较，测试高估收缩期跨瓣压差，瞬时最大跨瓣压差这一参数     

应用于零维左心血液循环的二尖瓣模型的研究

提出一个可以准确合理地模拟二尖瓣动力学特性的瓣叶运动流阻模型。考虑影响二尖瓣瓣叶运动的跨瓣压差和血流推力,建立二尖瓣运动的控制方程,提出依赖于瓣叶打开角度θ的瓣叶运动流阻模型,把该模型应用于零维左心血液循环系统,得到血液动力学特性。在保持心输出量和反流分数一致的条件下,比较该模型、瞬态关闭的阶梯流阻模型和经验指定的时变流阻模型。结果发现,瓣叶运动流阻模型能反映瓣膜关闭过程中的血液动力学,如压差和流量的滞后性以及关闭流量,同时该模型可以通过调整单位转动惯量跨瓣压差影响系数K_p和血流影响系数K_b的大小,改变瓣膜打开过程和关闭过程所需时间,瓣膜打开和关闭时间分别为50.0和40.2 ms。该模型可弥补阶梯流阻模型中忽略瓣膜运动过程的瞬态关闭的缺点,同时也能避免时变流阻模型中关闭起始时间的不合理性。此模型较为合理准确地模拟二尖瓣关闭过程的动力学特性,且简单易控制。     

同种主动脉瓣作为人工心瓣流体动力学特性测试标准参比瓣的研究——原位移植式安装、脉动流测试结果

本研究采用类似于临床原位移植方法,将同种动脉瓣固定在PS—1型装置的主动脉瓣位上。脉动流测试结果表明:此无结构和材料缺陷心瓣表现出理想心瓣特性:小而相对固定的瓣膜关闭容积、无舒张期泄漏、瓣环可扩张,在相对于正常成人的模拟心率和心输出量时,有效开口面积不小于其对应的肺动脉瓣环径解剖值。这是用此装置测试人工心瓣血流动力学性能的绝对标准。与在体正常值比较,测试高估收缩期跨瓣压差,瞬时最大跨瓣压差这一参数的意义值得怀疑。测试结果缺乏规律,模拟左室压力波形与病理波形一致,表明采用同种主动脉瓣作为人工心瓣脉动流测试的标准参比尚需进一步研究。     

CS无支架心包二尖瓣应用研究

目的比较传统有支架心包瓣与CS无支架心包二尖瓣的性能。方法测试瓣膜分为两组:A组,有支架心包瓣(与Ionescu-Shiley瓣相似);B组,无支架心包二尖瓣(与Quattro相似,由中南大学研制,简称CS瓣)。检测内容包括:①钙化倾向(SD鼠皮下埋藏模型);②组织学;③热皱缩温度;④断裂强度;⑤生物相容性;⑥血流动力学;⑦疲劳试验;⑧有限元分析。结果①B组钙化明显低于A组(P<0.01)。②组织学示A组心包片有大块钙化及胶元纤维裂解;B组仅见稍许钙化灶,胶原纤维保存完好。③热皱缩温度A组与B组无统计学意义。④断裂强度B组明显强于A组(P<0.005)。⑤内皮细胞种植后第1天,A组细胞明显少于B组(P<0.001);第3天A组已无细胞生长,B组内皮细胞增殖活跃;多数细胞Ⅷ因子检测呈阳性。⑥在模拟心输出量为2、4、6L,A组跨瓣压差明显高于B组(P<0.05),返流量和回流百分比A组显著高于B组(P<0.01),有效瓣口面积两组无统计学意义,仅在流量为4L时A组优于B组。⑦B组寿命比A组(n=2)长2.5倍。⑧B组瓣叶应力分布较为合理。结论CS无支架心包二尖瓣避免了应力集中区,其抗钙化、胶原纤维保存、断裂强度、生物相容性、血流动力学、疲劳寿命等均明显优于传统有支架心包瓣。     

The dawn of consumer-directed testing

As the public's interest in genetics and genomics has increased, there has been corresponding and unprecedented growth in direct-to-consumer genetic testing (DTC-GT). Although regulatory concerns have limited true DTC-GT available without a physician order, the paradigm has shifted to a model of consumer-directed genetic testing (CD-GT) in which patients are researching testing options and requesting specific genetic testing from their health-care providers. However, many nongenetics health-care providers do not have the background, education, interest, or time to order and/or interpret typical clinical genetic testing, let alone DTC-GT. The lines between CD-GT, DTC-GT, and traditional clinical genetic testing are also blurring with the same types of tests available in different settings (e.g., carrier screening) and tests merging medical and nonmedical results, increasing the complexity for consumer decision-making and clinician management. The genetics community has the training to work with CD-GT, but there has been a hesitancy to commit to working with these results and questions about what to do when consumers have more complicated asks, like interpretation of raw data. Additionally, at the rate with which CD-GT is growing, there are questions about having sufficient genetics professionals to meet the potential genetic counseling demand. While there are many complex questions and challenges, this market represents a chance for the genetics community to address and unmet need. We will review the history of the CD-GT/DTC-GT market and outline the issues and opportunities our profession is facing.     

Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) Practices of Sports Medicine Professionals

Context:

Computerized neurocognitive testing is becoming popular among clinicians evaluating sport-related concussions across all levels of sport. Baseline neurocognitive testing has been recommended to provide more accurate representation of the preconcussion cognitive status of individual athletes. However, little is known about the use of baseline neurocognitive testing in concussion assessment and management.

Objective:

To examine implementation and practice trends of sports medicine professionals using baseline neurocognitive testing at the high school and collegiate levels.

Design:

Quantitative survey research.

Setting:

Online survey.

Patients or Other Participants:

Certified athletic trainers (ATs) from approximately 1209 US institutions listed on the ImPACT Web site were recruited. A total of 399 ATs completed the survey, for a response return rate of 32.7%.

Main Outcome Measure(s):

Survey questions addressed educational level, years of certification, employment setting, percentage of athletes baseline tested, and accuracy of baseline tests. Other items addressed postconcussive neurocognitive testing protocols and scenarios for return-to-play decisions based on neurocognitive testing.

Results:

Nearly all ATs (94.7%) administered baseline computerized neurocognitive testing to their athletes. However, only 51.9% examined these baseline tests for validity. The majority of ATs indicated that they administer baseline neurocognitive tests most frequently to football players (88.4%), followed by women''s soccer players (78.8%) and men''s soccer players (71.2%). Nearly all respondents (95.5%) stated that they would not return a symptomatic athlete to play if the athlete''s neurocognitive scores were back to baseline. However, when asked if they would return an athlete who is symptom free but who scores below his or her baseline, 86.5% responded no, 9.8% responded yes, and 3.8% indicated that it depended on the importance of the competition.

Conclusions:

The use of baseline testing, baseline testing readministration, and postconcussion protocols among ATs is increasing. However, the ATs in this study reported that they relied more on symptoms than on neurocognitive test scores when making return-to-play decisions.     

Quality in genetic counselling for presymptomatic testing — clinical guidelines for practice across the range of genetic conditions

Presymptomatic testing (PST) is the performance of a genetic test on an asymptomatic individual at risk of a condition to determine whether the person has inherited the disease-causing mutation. Although relevant guidelines exist for specific diseases, there is no overarching protocol that can be adapted to any disorder or clinical setting in which such testing is offered. The objective of this European project was to develop a set of coherent guidelines for PST (for adult-onset monogenic conditions) for use by health professionals working in a range of disciplines, countries or contexts. To ensure the guidelines were appropriate and practice based, we organised a workshop attended by an expert group of practitioners with relevant health professional backgrounds from 11 countries. Models of service for offering PST were presented, the group then discussed different aspects of testing and the standard of care required to ensure that patients were prepared to make decisions and deal with results and consequences. After the workshop, several rounds of consultation were used with a wider group of professionals to refine the guidelines. The guidelines include general principles governing the offer of testing (eg, autonomous choice of the patient), objectives of genetic counselling in this context (eg, facilitation of decision making), logistical considerations (eg, use of trained staff) and topics to be included during counselling discussion with the patient (eg, consequences of both positive and negative outcomes). We recommend the adoption of these guidelines to provide an equitable structure for those seeking PST in any country.     

Cryopreservation of newly formed hybridomas

A new freezing technique is described which permits time-consuming protocols as a first screening of newly formed hybridomas. In this procedure complete 96 well clustertrays with growing hybridomas are cryopreserved after programmed freezing. This procedure has been successfully applied to a number of fusion protocols for which the objective was to obtain monoclonal antibodies against tissue specific antigens. To this end hybridoma supernatants were screened by an immunoperoxidase technique on frozen sections. Freezing of the hybridoma containing clustertrays permitted extensive screening and partial characterization of the previously collected supernatants. After subsequent thawing of appropriate wells, the hybridoma clones proved to be viable and usually no loss of antibody production was observed.     

磁力驱动轴流血泵溶血实验和动物实验

目的对研制开发的一种新型的磁力外驱动轴流式心室辅助血泵的血液相容性能进行测试。方法利用特制血袋作为模拟循环管道,羊血作为循环介质,采用标准溶血指数衡量体外溶血实验性能。通过3只山羊12h在体实验衡量其在体适应性。结果实验测得轴流血泵体外实验标准溶血指数(NIH)为(0.158±0.043)mg/L。3例实验动物12h在体辅助无机械故障,血泵辅助后实验动物血液中游离血红蛋白(FHb)开始上升,最高达到164.8mg/L。结论磁力外驱动轴流血泵实验结果比较理想,值得进一步改进。     

Clinical performance evaluation of Elecsys HIV Duo,Anti-HCV II,HBsAg II,Anti-HBc II,and Syphilis assays for routine screening of first-time blood donor samples at a French blood donation center

ObjectivesImplementing fully automated analyzers has become a crucial safety step in blood donation centers. The Elecsys® assays were evaluated on the cobas e 801 module (Roche Diagnostics) for routine first-time blood donor screening.Materials & MethodsFive Elecsys infectious disease assays were tested on the cobas e 801 module at Etablissement Français du Sang, Montpellier, France (March–April 2018). The performance of Elecsys HIV Duo, Anti-HCV II, HBsAg II, Anti-HBc II, and Syphilis assays was compared with PRISM HIV O Plus, HCV, HBsAg, HBcore, and newbio pk TPHA assays (specificity analyses)/ARCHITECT Syphilis TP (sensitivity analyses), respectively. Specificity was determined in residual fresh serum samples from unselected first-time blood donors (n ≥ 5195 per parameter). Elecsys assay sensitivity was tested using 30 preselected, positively characterized samples per assay and compared with archived routine testing data for comparator assays.ResultsAcross all parameters, specificities for repeatedly reactive samples ranged from 99.81–100.00% for Elecsys assays and 99.71–99.98% for comparator assays. Sensitivities of Elecsys and comparator assays were the same for hepatitis C (85.19%), hepatitis B surface antigen (70.00%), hepatitis B core antigen antibodies (100.00%), and syphilis (100.00%). The sensitivity of the Elecsys HIV Duo assay was higher than the comparator assay (83.33% vs. 76.67%), but the difference was not statistically significant.ConclusionsElecsys infectious disease assays on the cobas e 801 module demonstrated high specificity and sensitivity for screening first-time blood donor samples, and were comparable with other commercially available assays. The Elecsys assays are reliable tests for screening blood donations.     

CCMG guidelines: prenatal and postnatal diagnostic testing for uniparental disomy

The aim of this statement is to provide clinicians, cytogeneticists and molecular geneticists of the Canadian College of Medical Geneticists (CCMG) a comprehensive review of the role of UPD in constitutional genetic diagnosis and to provide a guideline as to when investigation for UPD is recommended. Members of the CCMG Cytogenetics, Molecular Genetics, Clinical Practice, and Prenatal Diagnosis committees reviewed the relevant literature on uniparental disomy (UPD) in constitutional genetic diagnosis (May 2010). Guidelines were developed for UPD testing in Canada. The guidelines were circulated for comment to the CCMG members at large and following appropriate modification, approved by the CCMG Board of Directors (July 2010).     

Use of the Abbott Architect HIV antigen/antibody assay in a low incidence population

BackgroundWith the availability of 4th generation HIV diagnostic tests which are capable of detecting acute infection, Iowa evaluated the 3rd and 4th generation HIV test and compared the performance of these products in a low incidence population.ObjectiveThis study was conducted to evaluate the performance of an HIV antigen/antibody combination (4th generation) assay compared to an EIA 3rd generation assay.Study designOver a 4 month period, 2037 specimens submitted for HIV screening were tested by Bio-Rad GS HIV-1/HIV-2 Plus O EIA and the Abbott Architect i1000SR HIV Ag/Ab Combo. The performance characteristics of sensitivity, specificity, positive predictive value and negative predictive value were determined.ResultsOf the 2037 specimens tested, there were 13 (0.64%) true positives detected. None of the positive specimens were from patients in the acute phase of infection. The Abbott antigen/antibody combo assay had a sensitivity, specificity, positive-predictive value and negative predictive value of 100%, 99.85%, 81.25%, and 100% respectively. The Bio-Rad EIA assay had a sensitivity, specificity, positive-predictive value and negative predictive value of 100%, 99.80%, 76.47% and 100%, respectively. The EIA had four false positive results which tested negative by the antigen/antibody assay and western blot.ConclusionIn a low-incidence state where early infections are less commonly encountered, the EIA assay and the antigen/antibody assay performed with near equivalency. The antigen/antibody assay had one less false positive result. While no patients were detected in the acute stage of infection, the use of the antigen/antibody assay presents the opportunity to detect an infected patient sooner and prevent transmission to others.     

Research on the mechanisms of action of aneugenic chemicals and regulatory approaches for their control in the European communities

The European Communities have developed a wide range of regulatory instruments for the control of chemical products sold and used within its geographical area. An important part of the testing requirements for most chemicals within the European Communities is the preparation of an information package on the potential mutagen properties of each chemical. Currently, no test requirements specify a unique test for aneugenic activity, although current methods such as in vitro cytogenetic and bone marrow micronucleus assays provide some useful indirect information on aneugenic activity. During the past 15 years the European Communities supported a series of collaborative research projects that have investigated the mechanisms by which chemicals induce aneuploidy and developmental studies of test methods for the detection of aneugenic chemicals. These projects led to the development of in vitro methods for the detection and quantification of induced nondisjunction and chromosome loss and the measurement of aneuploidy in rodent bone marrow. The European Communities projects have demonstrated the aneugenic potential of a diverse range of chemicals and their potential role in inherited disease and tumour induction. However, regulatory guidelines have yet to be modified to take advantage of the methods developed for the detection and evaluation of aneugenic chemicals. © 1996 Wiley-Liss, Inc.