1。准备 1.1。麻醉的老鼠<ol><li>将大鼠预先填充到腔室与异氟醚（约3分钟，5％的腔室的大小而定）麻醉大鼠。 </li><li>一旦麻醉，取出大鼠和称重。 </li><li>将鼻子的大鼠维持麻醉的麻醉面罩（异氟醚2-3％氧气1升/分钟）。在异氟醚麻醉大鼠心脏率下降到300-340 BPM（BPM在小鼠380-420）。 </li></ol> 1.2。插入一个尾静脉插管<ol><li>洗净用温水（38℃）和肥皂大鼠的尾部允许的血管更容易被看到。 </li><li>无论是静脉导管插入，它可以很容易地看到的尾部的外侧面上。使用一个22-24ĝ的静脉导管，开始尝试小费的方式，从约1/3。 </li><li>如果最初的努力是不成功的，近端重试。 </li><li>以血液SAM辉进行分析的血细胞比容（必要计算细胞外体积分数= ECV）。 </li><li>固定静脉导管与皮肤的胶水和胶带。 </li></ol> 1.3。电极定位<ol><li>饱和的酒精棉签或用肥皂和水清洗脚垫。 </li><li>四个电极是必要的，为每个脚之一。 </li><li>将足垫的中间电极，并用胶带固定。 </li><li>扭曲或辫子对方心电图电缆周围形成的循环，会导致ECG信号干扰降到最低。 </li></ol> 2。扫描 2.1。定位的动物和监测<ol><li>将大鼠仰卧或俯卧位上的摄像管中，并定位在心脏中的线圈中心。 </li><li>排列，所以，它的鼻子在于提供异氟醚麻醉（2-3％氧1L /分钟）在锥形大鼠。允许将大鼠呼吸自由在整个成像过程。 </li><li>在肛门口的温度计将传感器，并用胶带固定在桌子上。 </li><li>体温保持在38±1°C的温水加热系统。变暖垫被放置在延伸的外线圈的动物的下方面。请参见示意图MRI实验装置（ 图2）更多的细节。 </li><li>将ECG电极，一旦心电图信号是稳定开始成像。 </li></ol> 2.2。协议/影像扫描参数<ol><li>在这项研究中采用了飞利浦INGENIA 3.0T临床磁共振成像系统的电磁线圈70内径[MR系统的要求是小口径（ 如 16厘米）或大口径专用的小动物（人类的大小， 例如 65厘米）线圈，ECG门控功能的心脏速率高达500/min，供氧和麻醉气体清除系统]。 </li><li>开始一项调查，以核磁共振成像视场的中心的中心定位。 </li><li>一旦位置是正确的，则继续与两腔和四腔电影MRI的意见以确定的几何形状的短轴图像的堆栈。 </li><li>位置对于SALLI，中期腔短轴切片两和四腔图像（PreSALLI）。 4000毫秒采集持续时间和4000毫秒松弛持续时间的组合允许沿z轴的磁化有足够的恢复和防止过热的梯度。要启用的功能分析，相应设置为至少12，时空欠采样因子为2，加快收购。 </li><li>基于钆造影剂注入到留置导尿管，而移动鼠。等待5分钟。 </li><li>开始规划多层短轴栈，包括至少7片（切片厚度2.4毫米）SALLI。定位片，使最前端的心脏和t的顶点以下他顶层是远端心脏瓣膜。尝试，以确保短的轴垂直于隔垫。几乎每隔30分钟（大约三萨里斯）注入另一剂量造影剂。 </li><li>当完成图像采集从扫描仪中删除的大鼠，使其从麻醉中恢复。 </li></ol> 3。图像重建可以进行图像重建，在网上使用预定义的重建参数或离线使用专用的图像重建工具： 3.1。在线重建<ol><li>可以定义各种参数包括： </li></ol><ul><li>对于T1映射：重建窗口的位置和宽度的心动周期内（ 例如，从50到100毫秒至实现收缩T1的地图心律300/min） </li><li>对于红外准备的（LGE）图像：反转时间（TI）的位置和宽度窗口和数量的图像重建的Wi薄，窗口（ 如 TI 100-300毫秒，5幅图像，生成5 LG电子图像与TI的100-150-200-250-300毫秒）。 </li></ul> 3.2。离线重建<ol><li>当使用专用软件包（Gyrotools，Zürich，瑞士）进行图像重建，在一个更​​具交互性的方式提取的三组数据（电影MR，反转恢复和T1地图）。 </li><li>调整为T1通过选择相应的电影图像的最终收缩或舒张末期的定义。 </li><li> T1的地图可视化彩色地图。查找精确值，通过鼠标感兴趣的领域。图像可以存储在各种图像格式，以供进一步分析（ 例如，计算从对比度的前置和后置的T1值心肌和血池的ECV）12。 </li></ol>

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	<li>Messroghli, D. R., Nordmeyer, S., Buehrer, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Small+animal+Look-Locker+inversion+recovery+(SALLI)+for+simultaneous+generation+of+cardiac+T1+maps+and+cine+and+inversion+recovery-prepared+images+at+high+heart+rates:+initial+experience.">Small animal Look-Locker inversion recovery (SALLI) for simultaneous generation of cardiac T1 maps and cine and inversion recovery-prepared images at high heart rates: initial experience.</a> Radiology. 261 (1), 258-2565 (2011).</li><li>Messroghli, D. 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根据实验室动物护理和使用指南，所有动物的程序进行，由当地动物保健当局批准。没有利益冲突的声明。

在这里，我们提出了一种方法来生成小动物多模态（电影MR反转恢复和T1地图）MR图像。小动物的研究中扮演着越来越重要的作用，在心血管疾病的研究和CMR是一个强大的工具，使我们能够学习的功能，结构和组织组成的心肌。然而，小动物CMR有许多独特的挑战，由于高心脏和心脏大小小。在这项技术的发展，改进的成像方法，包括更多的时间有效的方法将进一步发挥作用。 ?...

心肌炎的一个主要原因是急性心脏衰竭，猝死，慢性扩张性心肌病7。 CMR已经建立的测量功能和体内组织分析的金标准技术。新型成像技术和改进在成像不仅可以提高诊断心肌炎，而且还帮助的病理生理研究和治疗靶点的速度辨识8-10。小动物成像是研究心血管疾病的一个重要工具。常规使用的技术，如在临床CMR晚钆增强（LGE）不能很容易地转移到小动物CMR由于高动物的心脏速率，但已经可以显示11。小动物看储物柜反转恢复方法（SALLI）生成的多模态图像数据，全面评估心脏功能和形态（ 图1设置允许ND 3）。这里，我们表明，在详细地说，程序和设置用于小动物成像一个典型的SALLI协议。特别是，我们表明T1成像数据集的重建和分析。

<table border="1">
		<tbody>
		 <tr>
			<td>Name of Reagent/Material</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		 </tr>
		 <tr>
			<td>Adhesive Tape (Silkafix)</td>
			<td>Lohmann und Rauscher</td>
			<td>34327</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Gadopentetat-Dimeglumin (Magnevist)</td>
			<td>Bayer</td>
			<td>G-00012163</td>
			<td>2mmol/Kg</td>
		 </tr>
		 <tr>
			<td>Introcan Safety-W (G24)</td>
			<td>B. Braun</td>
			<td>4254503-01</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Red Dot, Neonatal Monitoring Electrode with Pre-Attached Lead Wire</td>
			<td>3M</td>
			<td>2269T</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Skin glue (Histoacryl)</td>
			<td>B. Braun</td>
			<td>1050052</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Scales (Typ 440)</td>
			<td>Kern</td>
			<td>95088</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Skin desinfection (Softasept N)</td>
			<td>B. Braun Petzold</td>
			<td>360250</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Thermometer </td>
			<td>LumaSense Technologies</td>
			<td>Luxtron 812</td>
			<td></td>
		 </tr>
		</tbody>
 </table>

assessment of cardiac function and myocardial morphology using small animal look-locker inversion recovery (salli) mri in rats

小动物磁共振成像研究心脏功能和心肌组织的变化是一个重要的工具。心脏速率高的小动物（200〜600次/分）先前限于CMR成像的作用。小动物查找储物柜的反转恢复（SALLI）是一个小动物来克服这个问题1 T1映射序列。 T1的地图提供组织改建和造影剂动力学的定量信息。另外，也可以检测弥漫性过程，如心肌间质纤维化或水肿1-6。此外，从一个单一的图像数据集，它能够检查心脏功能和心肌疤痕通过生成电影和反转恢复制备的晚期钆增强型MR图像1。 视频显示一步一步的程序进行小动物CMR成像。在这里，它是一个健康成年DAWL的带有安永大鼠，然而自然地，它可以扩展到不同心脏的小动物模型。

在这里，我们展示了从健康成年大鼠结果。精心准备的动物设置，我们之前描述的，它有可能获得一个稳定的心电图信号。类似人类心脏MRI协议，我们开始一项调查，以找出心。如果大鼠在线圈的位置是正确的，我们将继续与二腔观和四腔观检测为SALLI堆栈的几何形状。 的SALLI技术产生三种类型的在同一时间获得的图像。这是，首先，电影的图像，可以用于研究局部和全局的L...

Watch this Scientific Journal Video about Assessment of Cardiac Function and Myocardial Morphology Using Small Animal Look-locker Inversion Recovery SALLI MRI in Rats at JoVE.com

Assessment of Cardiac Function and Myocardial Morphology Using Small Animal Look-locker Inversion Recovery SALLI MRI in Rats

对比度增强心脏磁共振（CMR）成像允许全面<em&gt;在体内</em&gt;评估心血管疾病的小动物模型的心脏。下面我们就详细的程序执行CMR成像，重建和分析，用小动物锁储物柜反转恢复（SALLI）的大鼠。

使用小动物看更衣室反转恢复（SALLI）的MRI大鼠心脏功能和心肌形态学评估

Small animal magnetic resonance  imaging is an important tool to study cardiac function and changes in myocardial  tissue. The high heart rates of small ...

assessment-cardiac-function-myocardial-morphology-using-small-animal

Research

JoVE Journal

Medicine

Assessment of Cardiac Function and Myocardial Morphology Using Small Animal Look-locker Inversion Recovery (SALLI) MRI in Rats

12.7K 次观看.  German Heart Institute Berlin. 对比度增强心脏磁共振（CMR）成像允许全面在体内评估心血管疾病的小动物模型的心脏。下面我们就详细的程序执行CMR成像，重建和分析，用小动物锁储物柜反转恢复（SALLI）的大鼠。

视频: Assessment of Cardiac Function and Myocardial Morphology Using Small Animal Look-locker Inversion Recovery SALLI MRI in Rats

Assessment of Cardiac Function and Energetics in Isolated Mouse Hearts Using 31P NMR Spectroscopy

Bioengineered mouse models have become powerful research tools in determining causal relationships between molecular alterations and models of cardiovascular disease. Although molecular biology is necessary in identifying key changes in the signaling pathway, it is not a surrogate for functional significance. While physiology can provide answers to the question of function, combining physiology with biochemical assessment of metabolites in the intact, beating heart allows for a complete picture of cardiac function and energetics. For years, our laboratory has utilized isolated heart perfusions combined with nuclear magnetic resonance (NMR) spectroscopy to accomplish this task. Left ventricular function is assessed by Langendorff-mode isolated heart perfusions while cardiac energetics is measured by performing 31P magnetic resonance spectroscopy of the perfused hearts. With these techniques, indices of cardiac function in combination with levels of phosphocreatine and ATP can be measured simultaneously in beating hearts. Furthermore, these parameters can be monitored while physiologic or pathologic stressors are instituted. For example, ischemia/reperfusion or high workload challenge protocols can be adopted. The use of aortic banding or other models of cardiac pathology are apt as well. Regardless of the variants within the protocol, the functional and energetic significance of molecular modifications of transgenic mouse models can be adequately described, leading to new insights into the associated enzymatic and metabolic pathways. Therefore, 31P NMR spectroscopy in the isolated perfused heart is a valuable research technique in animal models of cardiovascular disease.

Assessment of Cardiac Function and Energetics in Isolated Mouse Hearts Using 31P NMR Spectroscopy

Langendorff-mode isolated heart perfusion, in conjunction with 31P NMR spectroscopy, combines the fields of biochemistry and physiology into one experiment. The protocol allows for the dynamic measurement of high energy phosphate content and turnover in the heart while concurrently monitoring physiologic function. When performed correctly, this is a valuable technique in the assessment of cardiac energetics.

在分离的小鼠使用红桃心功能和能量学的评估 31 P核磁共振

Bioengineered mouse models have become powerful research tools in determining causal relationships between molecular alterations and models of ...

科研

医学

Acute Myocardial Infarction in Rats

With heart failure leading the cause of death in the USA (Hunt), biomedical research is fundamental to advance medical treatments for cardiovascular diseases. Animal models that mimic human cardiac disease, such as myocardial infarction (MI) and ischemia-reperfusion (IR) that induces heart failure as well as pressure-overload (transverse aortic constriction) that induces cardiac hypertrophy and heart failure (Goldman and Tarnavski), are useful models to study cardiovascular disease. In particular, myocardial ischemia (MI) is a leading cause for cardiovascular morbidity and mortality despite controlling certain risk factors such as arteriosclerosis and treatments via surgical intervention (Thygesen). Furthermore, an acute loss of the myocardium following myocardial ischemia (MI) results in increased loading conditions that induces ventricular remodeling of the infarcted border zone and the remote non-infarcted myocardium. Myocyte apoptosis, necrosis and the resultant increased hemodynamic load activate multiple biochemical intracellular signaling that initiates LV dilatation, hypertrophy, ventricular shape distortion, and collagen scar formation. This pathological remodeling and failure to normalize the increased wall stresses results in progressive dilatation, recruitment of the border zone myocardium into the scar, and eventually deterioration in myocardial contractile function (i.e. heart failure). The progression of LV dysfunction and heart failure in rats is similar to that observed in patients who sustain a large myocardial infarction, survive and subsequently develops heart failure (Goldman). The acute myocardial infarction (AMI) model in rats has been used to mimic human cardiovascular disease; specifically used to study cardiac signaling mechanisms associated with heart failure as well as to assess the contribution of therapeutic strategies for the treatment of heart failure. The method described in this report is the rat model of acute myocardial infarction (AMI). This model is also referred to as an acute ischemic cardiomyopathy or ischemia followed by reperfusion (IR); which is induced by an acute 30-minute period of ischemia by ligation of the left anterior descending artery (LAD) followed by reperfusion of the tissue by releasing the LAD ligation (Vasilyev and McConnell). This protocol will focus on assessment of the infarct size and the area-at-risk (AAR) by Evan's blue dye and triphenyl tetrazolium chloride (TTC) following 4-hours of reperfusion; additional comments toward the evaluation of cardiac function and remodeling by modifying the duration of reperfusion, is also presented. Overall, this AMI rat animal model is useful for studying the consequence of a myocardial infarction on cardiac pathophysiological and physiological function.

The rat model of acute myocardial infarction (AMI) is useful to study the consequence of a MI on cardiac pathophysiological and physiological function.

大鼠急性心肌梗死

With heart failure leading the cause of death in the USA (Hunt), biomedical research is fundamental to advance medical treatments for cardiovascular ...

Protocol for Long Duration Whole Body Hyperthermia in Mice

Hyperthermia is a general term used to define the increase in core body temperature above normal. It is often used to describe the increased core body temperature that is observed during fever. The use of hyperthermia as an adjuvant has emerged as a promising procedure for tumor regression in the field of cancer biology. For this purpose, the most important requirement is to have reliable and uniform heating protocols. We have developed a protocol for hyperthermia (whole body) in mice. In this protocol, animals are exposed to cycles of hyperthermia for 90 min followed by a rest period of 15 min. During this period mice have easy access to food and water. High body temperature spikes in the mice during first few hyperthermia exposure cycles are prevented by immobilizing the animal. Additionally, normal saline is administered in first few cycles to minimize the effects of dehydration. This protocol can simulate fever like conditions in mice up to 12-24 hr. We have used 8-12 weeks old BALB/Cj female mice to demonstrate the protocol.

This paper describes a protocol for whole body hyperthermia in mice that can stimulate fever like conditions up to 12-24 hr.

持续时间较长的小鼠全身热疗协议

Hyperthermia is a general term used to define the increase in core body temperature above normal. It is often used to describe the increased core body ...

MRI and PET in Mouse Models of Myocardial Infarction

Myocardial infarction is one of the leading causes of death in the Western world. The similarity of the mouse heart to the human heart has made it an ideal model for testing novel therapeutic strategies.
In vivo magnetic resonance imaging (MRI) gives excellent views of the heart noninvasively with clear anatomical detail, which can be used for accurate functional assessment. Contrast agents can provide basic measures of tissue viability but these are nonspecific. Positron emission tomography (PET) is a complementary technique that is highly specific for molecular imaging, but lacks the anatomical detail of MRI. Used together, these techniques offer a sensitive, specific and quantitative tool for the assessment of the heart in disease and recovery following treatment.
In this paper we explain how these methods are carried out in mouse models of acute myocardial infarction. The procedures described here were designed for the assessment of putative protective drug treatments. We used MRI to measure systolic function and infarct size with late gadolinium enhancement, and PET with fluorodeoxyglucose (FDG) to assess metabolic function in the infarcted region. The paper focuses on practical aspects such as slice planning, accurate gating, drug delivery, segmentation of images, and multimodal coregistration. The methods presented here achieve good repeatability and accuracy maintaining a high throughput.

We describe how to perform MRI and PET imaging of the mouse heart. The protocol is tailored to assess treatment efficacy in models of myocardial infarction and heart failure.

MRI和PET心肌梗死小鼠模型

Myocardial infarction is one of the leading causes of death in the Western world. The similarity of the mouse heart to the human heart has made it an ...

Ascending Aortic Constriction in Rats for Creation of Pressure Overload Cardiac Hypertrophy Model

Ascending aortic constriction is the most common and successful surgical model for creating pressure overload induced cardiac hypertrophy and heart failure. Here, we describe a detailed surgical procedure for creating pressure overload and cardiac hypertrophy in rats by constriction of the ascending aorta using a small metallic clip. After anesthesia, the trachea is intubated by inserting a cannula through a half way incision made between two cartilage rings of trachea. Then a skin incision is made at the level of the second intercostal space on the left chest wall and muscle layers are cleared to locate the ascending portion of aorta. The ascending aorta is constricted to 50&#8211;60% of its original diameter by application of a small sized titanium clip. Following aortic constriction, the second and third ribs are approximated with prolene sutures. The tracheal cannula is removed once spontaneous breathing was re-established. The animal is allowed to recover on the heating pad by gradually lowering anesthesia. The intensity of pressure overload created by constriction of the ascending aorta is determined by recording the pressure gradient using trans-thoracic two dimensional Doppler-echocardiography. Overall this protocol is useful to study the remodeling events and contractile properties of the heart during the gradual onset and progression from compensated cardiac hypertrophy to heart failure stage.

We describe a stepwise procedure for creating pressure overload and left ventricular hypertrophy in Wistar rats by constriction of the ascending aorta using a small metallic clip. This model is extensively used for studying remodeling changes during cardiac hypertrophy and for identifying and evaluating strategies for regression of such changes.

大鼠建立压力超负荷心肌肥厚模型在升主动脉缩窄

Ascending aortic constriction is the most common and successful surgical model for creating pressure overload induced cardiac hypertrophy and heart ...

Assessment of Right Ventricular Structure and Function in Mouse Model of Pulmonary Artery Constriction by Transthoracic Echocardiography

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, the RV is significantly affected in pulmonary diseases such as pulmonary artery hypertension (PAH). In addition, the RV is remarkably sensitive to cardiac pathologies, including left ventricular (LV) dysfunction, valvular disease or RV infarction4. To understand the role of RV in the pathogenesis of cardiac diseases, a reliable and noninvasive method to access the RV structurally and functionally is essential.
A noninvasive trans-thoracic echocardiography (TTE) based methodology was established and validated for monitoring dynamic changes in RV structure and function in adult mice. To impose RV stress, we employed a surgical model of pulmonary artery constriction (PAC) and measured the RV response over a 7-day period using a high-frequency ultrasound microimaging system. Sham operated mice were used as controls. Images were acquired in lightly anesthetized mice at baseline (before surgery), day 0 (immediately post-surgery), day 3, and day 7 (post-surgery). Data was analyzed offline using software.
Several acoustic windows (B, M, and Color Doppler modes), which can be consistently obtained in mice, allowed for reliable and reproducible measurement of RV structure (including RV wall thickness, end-diastolic&#160;and end-systolic dimensions), and function (fractional area change, fractional shortening, PA peak velocity, and peak pressure gradient) in normal mice and following PAC.
Using this method, the pressure-gradient resulting from PAC was accurately measured in real-time using Color Doppler mode and was comparable to direct pressure measurements performed with a Millar high-fidelity microtip catheter. Taken together, these data demonstrate that RV measurements obtained from various complimentary views using echocardiography are reliable, reproducible and can provide insights regarding RV structure and function. This method will enable a better understanding of the role of RV cardiac dysfunction.

Right ventricle (RV) dysfunction is critical to the pathogenesis of cardiovascular disease, yet limited methodologies are available for its evaluation. Recent advances in ultrasound imaging provide a noninvasive and accurate option for longitudinal RV study. Herein, we detail a step-by-step echocardiographic method using a murine model of RV pressure overload.

右心室结构和功能的肺动脉缩窄经胸超声小鼠模型的评估

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, ...

Echocardiographic and Histological Examination of Cardiac Morphology in the Mouse

An increasing number of genetically modified mouse models has become available in recent years. Moreover, the number of pharmacological studies performed in mice is high. Phenotypic characterization of these mouse models also requires the examination of cardiac function and morphology. Echocardiography and magnetic resonance imaging (MRI) are commonly used approaches to characterize cardiac function and morphology in mice. Echocardiographic and MRI equipment specialized for use in small rodents is&#160;expensive and requires a dedicated space. This protocol describes cardiac measurements in mice using a clinical echocardiographic system with a 15 MHz human vascular probe. Measurements are performed on anesthetized adult mice. At least three image sequences are recorded and analyzed for each animal in M-mode in the parasternal short-axis view. Afterwards, cardiac histological examination is performed, and cardiomyocyte diameters are determined on hematoxylin-eosin- or wheat germ agglutinin (WGA)-stained paraffin sections. Vessel density is determined morphometrically after Pecam-1 immunostaining. The protocol has been applied successfully to pharmacological studies and different genetic animal models under baseline conditions, as well as after experimental myocardial infarction by the permanent ligation of the left anterior descending coronary artery (LAD). In our experience, echocardiographic investigation is limited to anesthetized animals and is feasible in adult mice weighing at least 25 g.

Echocardiographic examination is frequently used in mice. Expensive high-resolution ultrasound devices have been developed for this purpose. This protocol describes an affordable echocardiographic procedure combined with histological morphometric analyses to determine cardiac morphology.

超声心动图与小鼠心脏形态学的组织学检查

An increasing number of genetically modified mouse models has become available in recent years. Moreover, the number of pharmacological studies performed ...

In Vivo Evaluation of Fracture Callus Development During Bone Healing in Mice Using an MRI-compatible Osteosynthesis Device for the Mouse Femur

Endochondral fracture healing is a complex process involving the development of fibrous, cartilaginous, and osseous tissue in the fracture callus. The amount of the different tissues in the callus provides important information on the fracture healing progress. Available in vivo techniques to longitudinally monitor the callus tissue development in preclinical fracture-healing studies using small animals include digital radiography and &#181;CT imaging. However, both techniques are only able to distinguish between mineralized and non-mineralized tissue. Consequently, it is impossible to discriminate cartilage from fibrous tissue. In contrast, magnetic resonance imaging (MRI) visualizes anatomical structures based on their water content and might therefore be able to noninvasively identify soft tissue and cartilage in the fracture callus. Here, we report the use of an MRI-compatible external fixator for the mouse femur to allow MRI scans during bone regeneration in mice. The experiments demonstrated that the fixator and a custom-made mounting device allow repetitive MRI scans, thus enabling longitudinal analysis of fracture-callus tissue development.

In Vivo Evaluation of Fracture Callus Development During Bone Healing in Mice Using an MRI-compatible Osteosynthesis Device for the Mouse Femur

The evaluation of tissue development in the fracture callus during endochondral bone healing is essential to monitor the healing process. Here, we report the use of a magnetic resonance imaging (MRI)-compatible external fixator for the mouse femur to allow MRI scans during bone regeneration in mice.

在体内MRI 对小鼠股骨骨愈合过程中骨折愈伤组织发育的评价

Endochondral fracture healing is a complex process involving the development of fibrous, cartilaginous, and osseous tissue in the fracture callus. The ...

Normothermic Ex Situ Heart Perfusion in Working Mode: Assessment of Cardiac Function and Metabolism

The current standard method for organ preservation (cold storage, CS), exposes the heart to a period of cold ischemia that limits the safe preservation time and increases the risk of adverse post-transplantation outcomes. Moreover, the static nature of CS does not allow for organ evaluation or intervention during the preservation interval. Normothermic ex situ heart perfusion (ESHP) is a novel method for preservation of the donated heart that minimizes cold ischemia by providing oxygenated, nutrient-rich perfusate to the heart. ESHP has been shown to be non-inferior to CS in the preservation of standard-criteria donor hearts and has also facilitated the clinical transplantation of the hearts donated after the circulatory determination of death. Currently, the only available clinical ESHP device perfuses the heart in an unloaded, non-working state, limiting assessments of myocardial performance. Conversely, ESHP in working mode provides the opportunity for comprehensive evaluation of cardiac performance by assessment of functional and metabolic parameters under physiologic conditions. Moreover, earlier experimental studies have suggested that ESHP in working mode may result in improved functional preservation. Here, we describe the protocol for ex situ perfusion of the heart in a large mammal (porcine) model, which is reproducible for different animal models and heart sizes. The software program in this ESHP apparatus allows for real-time and automated control of the pump speed to maintain desired aortic and left atrial pressure and evaluates a variety of functional and electrophysiological parameters with minimal need for supervision/manipulation.

Normothermic ex situ heart perfusion (ESHP), preserves the heart in a beating, semi-physiologic state. When performed in a working mode, ESHP provides the opportunity to perform sophisticated assessments of donor heart function and organ viability. Here, we describe our method for myocardial performance evaluation during ESHP.

工作模式下的心功能和代谢评估

The current standard method for organ preservation (cold storage, CS), exposes the heart to a period of cold ischemia that limits the safe preservation ...

Continuous Blood Sampling in Small Animal Positron Emission Tomography/Computed Tomography Enables the Measurement of the Arterial Input Function

For quantitative analysis and bio-kinetic modeling of positron emission tomography/computed tomography (PET/CT) data, the determination of the temporal blood time-activity concentration also known as arterial input function (AIF) is a key point, especially for the characterization of animal disease models and the introduction of newly developed radiotracers. The knowledge of radiotracer availability in the blood helps to interpret PET/CT-derived data of tissue activity. For this purpose, online blood sampling during the PET/CT imaging is advisable to measure the AIF. In contrast to manual blood sampling and image-derived approaches, continuous online blood sampling has several advantages. Besides the minimized blood loss, there is an improved resolution and a superior accuracy for the blood activity measurement. However, the major drawback of online blood sampling is the costly and time-consuming preparation to catheterize the femoral vessels of the animal. Here, we describe an easy and complete workflow for catheterization and continuous blood sampling during small animal PET/CT imaging and compared it to manual blood sampling and an image-derived approach. Using this highly-standardized workflow, the determination of the fluorodeoxyglucose ([18F]FDG) AIF is demonstrated. Further, this procedure can be applied to any radiotracer in combination with different animal models to create fundamental knowledge of tracer kinetic and model characteristics. This allows a more precise evaluation of the behavior of pharmaceuticals, both for diagnostic and therapeutic approaches in the preclinical research of oncological, neurodegenerative and myocardial diseases.

Here a protocol for continuous blood sampling during PET/CT imaging of rats to measure the arterial input function (AIF) is described. The catheterization, the calibration and setup of the system and the data analysis of the blood radioactivity are demonstrated. The generated data provide input parameters for subsequent bio-kinetic modeling.

小型动物正电子发射断层扫描/计算机断层扫描中的连续血液采样支持动脉输入函数的测量

For quantitative analysis and bio-kinetic modeling of positron emission tomography/computed tomography (PET/CT) data, the determination of the temporal ...