作者感谢蓝沁博士和Shane Stanek收集数据的帮助。

<ol>
	<li>Low, P. A., Denq, J. C., Opfer-Gehrking, T. L., Dyck, P. J., O'Brien, P. C., Slezak, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+age+and+gender+on+sudomotor+and+cardiovagal+function+and+blood+pressure+response+to+tilt+in+normal+subjects.">Effect of age and gender on sudomotor and cardiovagal function and blood pressure response to tilt in normal subjects.</a> Muscle Nerve. 20, 1561-1568 (1997).</li><li>Low, P. A., Denq, J. C., Opfer-Gehrking, T. L., Dyck, P. J., O'Brien, P. C., Slezak, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+age+and+gender+on+sudomotor+and+cardiovagal+function+and+blood+pressure+response+to+tilt+in+normal+subjects.">Effect of age and gender on sudomotor and cardiovagal function and blood pressure response to tilt in normal subjects.</a> Muscle Nerve. 20, 1561-1568 (1997).</li><li>Low, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Composite+autonomic+scoring+scale+for+laboratory+quantification+of+generalized+autonomic+failure.">Composite autonomic scoring scale for laboratory quantification of generalized autonomic failure.</a> Mayo Clin Proc. 68, 748-752 (1993).</li><li>Low, P. A., Low, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laboratory+evaluation+of+autonomic+function.">Laboratory evaluation of autonomic function.</a> Clinical Autonomic disorders. , 179-209 (1997).</li><li>Low, P. A., Low, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laboratory+evaluation+of+autonomic+failure.">Laboratory evaluation of autonomic failure.</a> Clinical Autonomic disorders. , 179-209 (2008).</li><li>Novak, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+sympathetic+index+from+Valsalva+maneuver.">Assessment of sympathetic index from Valsalva maneuver.</a> Neurology. , (2011).</li></ol>

陷阱完成自主测试在大多数患者简单的，可以在1个小时内完成。特别是每个测试步骤的陷阱是在下面讨论。 设备，数据采集和处理自主信号。 有主要涉及到数据的质量缺陷的数目。不足清洁皮肤，可导致过量噪音，可以使心电信号的R波检测困难。血压传感器我放置不当，提供虚假的高或低价值的。经颅多普勒信号质量高，可由于小骨窗老年患者很难得到。可能没有足够强大的区分文物例如帕金森患者的震颤，血压的数据处理软件。 深呼吸<ol><li>焦虑和不正常的呼吸模式可能会影响深呼吸的结果。在测试过程中的主体应得到很好的放松。焦虑的一个良好指标是心率配置文件。如果主题是着急，可升高，心率。深呼吸测试开始之前，确保心率是不是趋势向上或向下，如果发生这种情况的等待，直到平均心率保持平坦。休息时呼吸模式应该是正常的，例如，不应该有过度换气（年底潮汐的CO 2测量）或呼吸急促（呼吸频率是每分钟11以上） 。 </li><li>深呼吸的测试有限的，例如，在房颤时心率起搏器控制在一定的心脏dysrythmia实用性，因为心脏的迷走神经调制将会由心脏产生的节奏，或心脏起搏器覆盖。心律异常的基本知识，建议。 </li><li> R波因工件的不适当的检测，显然会导致结果错误。这可以发生，如果R波太小，无法可靠地检测，如果心电图背景是嘈杂例如由于皮肤接触不佳。 </li></ol> Valsalva动作 Valsalva动作，需要相当大的合作，从学科，许多老人或体弱的患者不能正确执行Valsalva动作。最常见的原因是口肌肉无力，漏气的结果，在呼吸株。在这种情况下，它是有效的温柔围绕管密封漏气， 用手指6。 肾上腺素功能的评价不能做Valsalva动作（ 图10）的方波变种。这种反应是罕见的，但可以在健康受试者或充血性心力衰竭患者。 倾斜试验用药次数可能会影响测试难度倾斜测试渲染解释。它并不总是可行的测试前停止服药。 这可能是难以取得良好的品质的录音，例如帕金森患者的震颤，运动障碍的病人。 Sudomotor测试（QSART） <ol><li>不完全去除油性表面或皮肤刺激太大，影响汗液的输出。 </li><li>泄漏胶囊不水密或疼痛，由于太多紧张胶囊</li><li>常用的药物有抗胆碱作用，干扰与汗水测试。在许多情况下，是不切实际的，停止这些药物渲染结果难以解释。 </li></ol>植物神经障碍分级使用综合自主严重性分数（中国社会科学院）。 中国社会科学院得分的产生是相当麻烦的，因为它涉及到在绝对值和百分比值的多重比较。不幸的是，没有任何商业软件，能够自动计算得分。在麻省大学，我们使用专有软件自动生成中国社会科学院得分的。中国社会科学院分数的例子是表 8 。

表9推荐的设备。 <table border="1"><tbody><tr><td> 设备名称 </td><td> 公司 </td><td> 评论 </td></tr><tr><td>电动倾斜表</td><td> WR医疗电子</td><td>任何运动平稳表5-10秒内达到70度</td></tr><tr><td>心电监护仪</td><td></td><td>任何模拟输出设备</td></tr><tr><td>无创性的节拍拍血压监测</td><td> Finapres医疗系统</td><td>几个型号可供选择，都是相似的</td></tr><tr><td> Q -汗水</td><td> WR医疗电子</td><td></td></tr><tr><td>经颅多普勒超声</td><td></td><td>任何模拟输出设备</td></tr><tr><td>录音系统</td><td> LabChart，ADInstruments </td><td>简单的编程</td></tr><tr><td>录音系统</td><td> Labview的</td><td>复杂的编程</td></tr><tr><td>录音系统</td><td> Matlab的</td><td>复杂的编程</td></tr><tr><td>录音系统</td><td>西铁医疗</td><td>随时使用，但有限的灵活性</td></tr><tr><td>二氧化碳监测</td><td></td><td>睡眠研究中使用的许多型号</td></tr><tr><td>呼吸监测</td><td></td><td>简单的热敏电阻连接到录音系统</td></tr></tbody></table>

quantitative autonomic testing

与植物神经系统功能紊乱相关的疾病是相当普遍，但经常无法识别。定量自主测试可以评价这些疾病的宝贵工具，无论是在诊所和研究。有自主测试，然而，只有少数进行了验证临床或定量。在这里，测试植物神经功能全面的定量和临床验证协议。作为最低限度的临床植物神经实验室应该有倾斜，心电监护仪，连续无创血压监测，呼吸监测和评价sudomotor域平均。自主测试的记录和评价软件数据的正确评价的关键。所提出的协议进行评估的3个主要的自主域:cardiovagal，肾上腺素和sudomotor。测试包括深呼吸，Valsalva动作，头部倾斜，定量的sudomotor轴突测试（QSART）。使用复合自主严重程度评分（社科院）的严重性和分布的dysautonomia定量。提供详细的协议是突出强调正确的数据采集与测试的重要方面，获得自主信号的相关参数和不带偏见的评价。以及提供规范的数据和结果的解释中国社会科学院算法。

Watch this Scientific Journal Video about Quantitative Autonomic Testing at JoVE.com

Quantitative Autonomic Testing

植物神经功能测试规范，全面和充分的定量描述。自主测试包括所有三个主要包括cardiovagal，肾上腺素和sudomotor自主域的评价。使用复合材料的自主严重程度评分是定量的严重性和分布的dysautonomia。

定量自主测试

Disorders associated with dysfunction of autonomic nervous system are quite common yet frequently unrecognized. Quantitative autonomic testing can be ...

Research

Education

JoVE Core

JoVE Journal

Pharmacology

Medicine

Unit 1

Drugs Acting on Autonomic Nervous System: Cholinergic Agonists and Antagonists Agents

SCIENTISTS IN ACTION

56.4K 次观看.  University of Massachusetts Medical School. 植物神经功能测试规范，全面和充分的定量描述。自主测试包括所有三个主要包括cardiovagal，肾上腺素和sudomotor自主域的评价。使用复合材料的自主严重程度评分是定量的严重性和分布的dysautonomia。

视频: Quantitative Autonomic Testing

Quantitative Analysis of Chromatin Proteomes in Disease

In the nucleus reside the proteomes whose functions are most intimately linked with gene regulation. Adult mammalian cardiomyocyte nuclei are unique due to the high percentage of binucleated cells,1 the predominantly heterochromatic state of the DNA, and the non-dividing nature of the cardiomyocyte which renders adult nuclei in a permanent state of interphase.2 Transcriptional regulation during development and disease have been well studied in this organ,3-5 but what remains relatively unexplored is the role played by the nuclear proteins responsible for DNA packaging and expression, and how these proteins control changes in transcriptional programs that occur during disease.6 In the developed world, heart disease is the number one cause of mortality for both men and women.7 Insight on how nuclear proteins cooperate to regulate the progression of this disease is critical for advancing the current treatment options.
Mass spectrometry is the ideal tool for addressing these questions as it allows for an unbiased annotation of the nuclear proteome and relative quantification for how the abundance of these proteins changes with disease. While there have been several proteomic studies for mammalian nuclear protein complexes,8-13 until recently14 there has been only one study examining the cardiac nuclear proteome, and it considered the entire nucleus, rather than exploring the proteome at the level of nuclear sub compartments.15 In large part, this shortage of work is due to the difficulty of isolating cardiac nuclei. Cardiac nuclei occur within a rigid and dense actin-myosin apparatus to which they are connected via multiple extensions from the endoplasmic reticulum, to the extent that myocyte contraction alters their overall shape.16 Additionally, cardiomyocytes are 40% mitochondria by volume17 which necessitates enrichment of the nucleus apart from the other organelles. Here we describe a protocol for cardiac nuclear enrichment and further fractionation into biologically-relevant compartments. Furthermore, we detail methods for label-free quantitative mass spectrometric dissection of these fractions-techniques amenable to in vivo experimentation in various animal models and organ systems where metabolic labeling is not feasible.

Advances in mass spectrometry have allowed the high throughput analysis of protein expression and modification in a host of tissues. Combined with subcellular fractionation and disease models, quantitative mass spectrometry and bioinformatics can reveal new properties in biological systems. The method described herein analyzes chromatin-associated proteins in the setting of heart disease and is readily applicable to other in vivo models of human disease.

在疾病的染色质蛋白质组的定量分析

In the nucleus reside the proteomes whose functions are most intimately linked with gene regulation. Adult mammalian cardiomyocyte nuclei are unique due ...

科研

医学

Measuring Cardiac Autonomic Nervous System (ANS) Activity in Children

The autonomic nervous system (ANS) controls mainly automatic bodily functions that are engaged in homeostasis, like heart rate, digestion, respiratory rate, salivation, perspiration and renal function. The ANS has two main branches: the sympathetic nervous system, preparing the human body for action in times of danger and stress, and the parasympathetic nervous system, which regulates the resting state of the body.
ANS activity can be measured invasively, for instance by radiotracer techniques or microelectrode recording from superficial nerves, or it can be measured non-invasively by using changes in an organ's response as a proxy for changes in ANS activity, for instance of the sweat glands or the heart. Invasive measurements have the highest validity but are very poorly feasible in large scale samples where non-invasive measures are the preferred approach. Autonomic effects on the heart can be reliably quantified by the recording of the electrocardiogram (ECG) in combination with the impedance cardiogram (ICG), which reflects the changes in thorax impedance in response to respiration and the ejection of blood from the ventricle into the aorta. From the respiration and ECG signals, respiratory sinus arrhythmia can be extracted as a measure of cardiac parasympathetic control. From the ECG and the left ventricular ejection signals, the preejection period can be extracted as a measure of cardiac sympathetic control. ECG and ICG recording is mostly done in laboratory settings. However, having the subjects report to a laboratory greatly reduces ecological validity, is not always doable in large scale epidemiological studies, and can be intimidating for young children. An ambulatory device for ECG and ICG simultaneously resolves these three problems.
Here, we present a study design for a minimally invasive and rapid assessment of cardiac autonomic control in children, using a validated ambulatory device 1-5, the VU University Ambulatory Monitoring System (VU-AMS, Amsterdam, the Netherlands,<a href="http://www.vu-ams.nl" target="_blank"> www.vu-ams.nl</a>).

Measuring Cardiac Autonomic Nervous System ANS Activity in Children

Measurement of autonomic nervous system activity usually confines the researcher and participant to the laboratory, which may provide an intimidating environment to children. The VU University Ambulatory Monitoring System (VU-AMS) device can record cardiac autonomic control in any setting. The VU-AMS proved very amenable to testing in children.

测量心脏自主神经系统（ANS）儿童活动

The autonomic nervous system (ANS) controls mainly automatic bodily functions that are engaged in homeostasis, like heart rate, digestion, respiratory ...

Minimal Erythema Dose (MED) Testing

Ultraviolet radiation (UV) therapy is sometimes used as a treatment for various common skin conditions, including psoriasis, acne, and eczema. The dosage of UV light is prescribed according to an individual's skin sensitivity. Thus, to establish the proper dosage of UV light to administer to a patient, the patient is sometimes screened to determine a minimal erythema dose (MED), which is the amount of UV radiation that will produce minimal erythema (sunburn or redness caused by engorgement of capillaries) of an individual's skin within a few hours following exposure. This article describes how to conduct minimal erythema dose (MED) testing. There is currently no easy way to determine an appropriate UV dose for clinical or research purposes without conducting formal MED testing, requiring observation hours after testing, or informal trial and error testing with the risks of under- or over-dosing. However, some alternative methods are discussed.

Minimal Erythema Dose MED Testing

This article describes how to conduct minimal erythema dose (MED) testing in order to determine the lowest dose of ultraviolet radiation that will cause erythema (burning) when administered to an individual.

最小红斑剂量（MED）测试

Ultraviolet radiation (UV) therapy is  sometimes used as a treatment for various common skin conditions, including  psoriasis, acne, and eczema. The ...

A Novel Application of Musculoskeletal Ultrasound Imaging

Ultrasound is an attractive modality for imaging muscle and tendon motion during dynamic tasks and can provide a complementary methodological approach for biomechanical studies in a clinical or laboratory setting. Towards this goal, methods for quantification of muscle kinematics from ultrasound imagery are being developed based on image processing. The temporal resolution of these methods is typically not sufficient for highly dynamic tasks, such as drop-landing. We propose a new approach that utilizes a Doppler method for quantifying muscle kinematics. We have developed a novel vector tissue Doppler imaging (vTDI) technique that can be used to measure musculoskeletal contraction velocity, strain and strain rate with sub-millisecond temporal resolution during dynamic activities using ultrasound. The goal of this preliminary study was to investigate the repeatability and potential applicability of the vTDI technique in measuring musculoskeletal velocities during a drop-landing task, in healthy subjects. The vTDI measurements can be performed concurrently with other biomechanical techniques, such as 3D motion capture for joint kinematics and kinetics, electromyography for timing of muscle activation and force plates for ground reaction force. Integration of these complementary techniques could lead to a better understanding of dynamic muscle function and dysfunction underlying the pathogenesis and pathophysiology of musculoskeletal disorders.

We describe a new ultrasound-based vector tissue Doppler imaging technique to measure muscle contraction velocity, strain and strain rate with sub-millisecond temporal resolution during dynamic activities. This approach provides complementary measurements of dynamic muscle function and could lead to a better understanding of mechanisms underlying musculoskeletal disorders.

肌肉骨骼超声成像的一种新应用

Ultrasound is an attractive modality for imaging muscle and tendon  motion during dynamic tasks and can provide a complementary methodological  approach ...

Cerebrospinal Fluid MicroRNA Profiling Using Quantitative Real Time PCR

MicroRNAs (miRNAs) constitute a potent layer of gene regulation by guiding RISC to target sites located on mRNAs and, consequently, by modulating their translational repression. Changes in miRNA expression have been shown to be involved in the development of all major complex diseases. Furthermore, recent findings showed that miRNAs can be secreted to the extracellular environment and enter the bloodstream and other body fluids where they can circulate with high stability. The function of such circulating miRNAs remains largely elusive, but systematic high throughput approaches, such as miRNA profiling arrays, have lead to the identification of miRNA signatures in several pathological conditions, including neurodegenerative disorders and several types of cancers. In this context, the identification of miRNA expression profile in the cerebrospinal fluid, as reported in our recent study, makes miRNAs attractive candidates for biomarker analysis.
There are several tools available for profiling microRNAs, such as microarrays, quantitative real-time PCR (qPCR), and deep sequencing. Here, we describe a sensitive method to profile microRNAs in cerebrospinal fluids by quantitative real-time PCR. We used the Exiqon microRNA ready-to-use PCR human panels I and II V2.R, which allows detection of 742 unique human microRNAs. We performed the arrays in triplicate runs and we processed and analyzed data using the GenEx Professional 5 software.
Using this protocol, we have successfully profiled microRNAs in various types of cell lines and primary cells, CSF, plasma, and formalin-fixed paraffin-embedded tissues.

We describe a protocol of real time PCR to profile microRNAs in the cerebrospinal fluid (CSF). With the exception of RNA extraction protocols, the procedure can be extended to RNA extracted from other body fluids, cultured cells, or tissue specimens.

脑脊液的microRNA分析采用实时定量PCR技术

MicroRNAs (miRNAs) constitute a potent layer of gene regulation by guiding RISC to target sites located on mRNAs and, consequently, by modulating their ...

Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease

Quantitative magnetic resonance imaging (qMRI) describes the development and use of MRI to quantify physical, chemical, and/or biological properties of living systems. Neuromuscular diseases often exhibit a temporally varying, spatially heterogeneous, and multi-faceted pathology. The goal of this protocol is to characterize this pathology using qMRI methods. The MRI acquisition protocol begins with localizer images (used to locate the position of the body and tissue of interest within the MRI system), quality control measurements of relevant magnetic field distributions, and structural imaging for general anatomical characterization. The qMRI portion of the protocol includes measurements of the longitudinal and transverse relaxation time constants (T1 and T2, respectively). Also acquired are diffusion-tensor MRI data, in which water diffusivity is measured and used to infer pathological processes such as edema. Quantitative magnetization transfer imaging is used to characterize the relative tissue content of macromolecular and free water protons. Lastly, fat-water MRI methods are used to characterize fibro-adipose tissue replacement of muscle. In addition to describing the data acquisition and analysis procedures, this paper also discusses the potential problems associated with these methods, the analysis and interpretation of the data, MRI safety, and strategies for artifact reduction and protocol optimization.

Neuromuscular diseases often exhibit a temporally varying, spatially heterogeneous, and multi-faceted pathology. The goal of this protocol is to characterize this pathology using non-invasive magnetic resonance imaging methods.

骨骼肌疾病的定量磁共振成像

Quantitative magnetic resonance imaging (qMRI) describes the development and use of MRI to quantify physical, chemical, and/or biological properties of ...

Quantitative Fundus Autofluorescence for the Evaluation of Retinal Diseases

The retinal pigment epithelium (RPE) is juxtaposed to the overlying sensory retina, and supports the function of the visual system. Among the tasks performed by the RPE are phagocytosis and processing of outer photoreceptor segments through lysosome-derived organelles. These degradation products, stored and referred to as lipofuscin granules, are composed partially of bisretinoids, which have broad fluorescence absorption and emission spectra that can be detected clinically as fundus autofluorescence with confocal scanning laser ophthalmoscopy (cSLO). Lipofuscin accumulation is associated with increasing age, but is also found in various patterns in both acquired and inherited degenerative diseases of the retina. Thus, studying its pattern of accumulation and correlating such patterns with changes in the overlying sensory retina are essential to understanding the pathophysiology and progression of retinal disease. Here, we describe a technique employed by our lab and others that uses cSLO in order to quantify the level of RPE lipofuscin in both healthy and diseased eyes.

The retinal pigment epithelium (RPE) supports the sensory retina through recycling visual cycle byproducts, which accumulate as lipofuscin. These products are autofluorescent and can be qualitatively imaged in vivo. Here, we describe a method to quantitatively image RPE lipofuscin using confocal scanning laser ophthalmoscopy.

定量自体荧光眼底视网膜疾病的评价

The retinal pigment epithelium (RPE) is juxtaposed to the overlying sensory retina, and supports the function of the visual system. Among the tasks ...

Measuring Cardiac Autonomic Nervous System (ANS) Activity in Toddlers - Resting and Developmental Challenges

The autonomic nervous system (ANS) consists of two branches, the parasympathetic and sympathetic nervous systems, and controls the function of internal organs (e.g., heart rate, respiration, digestion) and responds to everyday and adverse experiences 1. ANS measures in children have been found to be related to behavior problems, emotion regulation, and health 2-7. Therefore, understanding the factors that affect ANS development during early childhood is important. Both branches of the ANS affect young children&#8217;s cardiovascular responses to stimuli and have been measured noninvasively, via external monitoring equipment, using valid and reliable measures of physiological change 8-11. However, there are few studies of very young children with simultaneous measures of the parasympathetic and sympathetic nervous systems, which limits understanding of the integrated functioning of the two systems. In addition, the majority of existing studies of young children report on infants&#8217; resting ANS measures or their reactivity to commonly used mother-child interaction paradigms, and less is known about ANS reactivity to other challenging conditions. We present a study design and standardized protocol for a non-invasive and rapid assessment of cardiac autonomic control in 18 month old children. We describe methods for continuous monitoring of the parasympathetic and sympathetic branches of the ANS under resting and challenge conditions during a home or laboratory visit and provide descriptive findings from our sample of 140 ethnically diverse toddlers using validated equipment and scoring software. Results revealed that this protocol can produce a range of&#160;physiological responses to both resting and developmentally challenging conditions, as indicated by changes in heart rate and indices of parasympathetic and sympathetic activity. Individuals demonstrated&#160;variability in resting levels, responses to challenges, and challenge reactivity, which provides additional evidence that this protocol is useful for the examination of ANS individual differences for toddlers.

Measuring Cardiac Autonomic Nervous System ANS Activity in Toddlers - Resting and Developmental Challenges

We describe the methods for continuous monitoring of the autonomic nervous system under resting and challenge conditions with 18 month old children. Results revealed that this protocol can produce meaningful physiological responses in both branches of the autonomic nervous system and elicit significant individual variability in patterns of responses.

测量心脏自主神经系统（ANS）活性的幼儿 - 安静和发展挑战

The autonomic nervous system (ANS) consists of two branches, the parasympathetic and sympathetic nervous systems, and controls the function of internal ...

Intracoronary Acetylcholine Provocation Testing for Assessment of Coronary Vasomotor Disorders

Intracoronary acetylcholine provocation testing (ACH-test) is an established method for assessment of epicardial coronary artery spasm in the catheterization laboratory which was introduced more than 30 years ago. Due to the short half-life of acetylcholine it can only be applied directly into the coronary arteries. Several studies have demonstrated the safety and clinical usefulness of this test. However, acetylcholine testing is only rarely applied in the U.S. or Europe. Nevertheless, it has been shown that 62% of Caucasian patients with stable angina and unobstructed coronary arteries on coronary angiography suffer from coronary vasomotor disorders that can be diagnosed with acetylcholine testing. In recent years it has been appreciated that the ACH-test not only assesses the presence of epicardial spasm but that it can also be useful for the detection of coronary microvascular spam. In such cases no epicardial spasm is seen after injection of acetylcholine but ischemic ECG shifts are present together with a reproduction of the patient's symptoms during the test. This article describes the experience with the ACH-test and its implementation in daily clinical routine.

Intracoronary acetylcholine testing has been established for the assessment of epicardial coronary spasm more than 30 years ago. Recently, the focus has shifted towards the microcirculation and it has been shown that microvascular spasm can be detected using ACH-testing. This article describes the ACH-test and its implementation in daily routine.

冠状动脉内乙酰胆碱激发试验冠状动脉的血管收缩评估疾病

Intracoronary acetylcholine provocation testing (ACH-test) is an established method for assessment of epicardial coronary artery spasm in the ...

Proximal Cadaveric Femur Preparation for Fracture Strength Testing and Quantitative CT-based Finite Element Analysis

Cadaveric fracture testing is routinely used to understand factors that affect proximal femur strength. Because ex vivo biological tissues are prone to lose their mechanical properties over time, specimen preparation for experimental testing must be performed carefully to obtain reliable results that represent in vivo conditions. For that reason, we designed a protocol and a set of fixtures to prepare the femoral specimens such that their mechanical properties experienced minimal changes. The femora were kept in a frozen state except during preparation steps and mechanical testing. The relevant clinical measures of total hip and femoral neck bone mineral density (BMD) were obtained with a clinical dual X-ray absorptiometry (DXA) bone densitometer, and the 3D geometry and distribution of bone mineral were obtained using CT with a calibration phantom for quantitative estimations based on the greyscale values. Any possible bone disease, fracture, or the presence of implants or artifacts affecting the bone structure, was ruled out with X-ray scans. For preparation, all bones were carefully cleaned of excess soft tissue, and were cut and potted at the internal rotation angle of interest. A cutting fixture allowed the distal end of the bone to be cut off leaving the proximal femur at a desired length. To allow positioning of the femoral neck at prescribed angles during later CT scanning and mechanical testing, the proximal femoral shafts were potted in polymethylmethacrylate (PMMA) using a fixture designed specifically for desired orientations. The data collected from our experiments were then used for validation of quantitative computed tomography (QCT)-based finite element analysis (FEA), as described in a different protocol. In this manuscript, we present the protocol for the precise bone preparation for mechanical testing and subsequent QCT/FEA modeling. The current protocol was successfully applied to prepare about 200 cadaveric femora over a 6-year time period.

We present a robust protocol on how to carefully preserve and prepare cadaveric femora for fracture testing and quantitative computed tomography imaging. The method provides precise control over input conditions for the purpose of determining relationships between bone mineral density, fracture strength, and defining finite element model geometry and properties.

近端股骨尸制备基于CT的断裂强度测试和定量的有限元分析

Cadaveric fracture testing is routinely used to understand factors that affect proximal femur strength.  Because ex vivo biological tissues are prone to ...