资助，这项工作的一部分，由NIH资助HL087653和HL105314。在博士罗伯特Mecham的实验室在华盛顿大学医学院的一些方法。

1。超声和​​压力系统<ol><li>根据制造商的说明（VEVO 770，Visualsonics）的启动超声系统。填写适当的探针（年龄E18 - P7的= 708，年龄&gt; P7的模型707B模型），用蒸馏水和连接的超声系统。探头放置在可调底座的大致方位，要获得一个LV长轴成像平台上安装鼠标，使LV尖向注射胳膊指出。 </li><li>压力系统由一个充满液体的压力传感器，桥式放大器，数据采集系统和数据记录软件（LabChart）。三通旋塞，油管，鲁尔锁和软管倒钩连接组成。 20 ml注射器充满10％的肝素生理盐水冲洗一端。另一端连接到一根针和3毫升注射器的身体保持在针管注射的手臂（图1）作为外壳使用的修改。 </li><l我&gt;校准与压力表压力传感器系统。 </li><li>安装在超声系统注入手臂的针管和套管。中环站钳压力传感器，在成像平台的近似高度。将鼠标的年龄（年龄E18 - P3 = 30G，年龄&gt; P3的= 25G）适当的针管一针。较小的针头得到更容易堵塞，更难以通过胸壁推进，有一个较慢的响应时间。因此，最大的针头大小，适合在LV腔用于各年龄段。 </li><li>超声凝胶成像平台上放置一个土堆，仔细排队探头针，这样可以提前进入凝胶直接下的成像探针中心（图2）使用可调底座。针必须足够远低于探头穿刺探头盖，但足够接近内探测震源深度。如果有必要，可弯针，手工，所以它仍然在日Ë正确的飞机在其整个旅行。 </li><li>保持对齐，收回针，并提高了成像探测成像平台上放置一个鼠标。冲洗针，以消除任何可能已进入尖端的凝胶。 </li></ol> 2。鼠标准备<ol><li>制度的动物护理和使用委员会已批准在本协议中的所有方法。定时怀孕的母亲（E18）或新生鼠（P1 - 20）持续吸入1.5％异氟醚麻醉。管道可以插入到一个标准的鼻锥，早日新生鼠（P1 - 15），以适应小头。 </li><li>确保鼠标在背LV尖对注射手臂指向卧位超声系统成像平台。对于孕妇，应用超声的凝胶监测与心率附加心电图探测器的插入直肠温度计体温反馈控制。新生鼠过小F这些探测器，使心率监测在压力测量体温保持与外部的热灯。 </li><li>从对孕妇的腹部或胸部的小老鼠用脱毛霜的头发。新生鼠（P1 - 10）不需要任何脱毛。 </li><li>对于孕妇，剖开腹​​部，用解剖剪刀，弯钳。外部一个子宫角和地方纱布蘸温盐水。仔细地操纵胚胎，到适当的位置，获得的LV 1胸骨旁长轴观，用超声探头。这一边测量外其他子宫角前，在所有胚胎的压力。保留所有胚胎和定期此外温生理盐水湿润的母亲的腹部。 </li></ol> 3。压力测量<ol><li>地方预热，脱气超声凝胶，对胚胎或新生鼠。新生小鼠仍未ðepilated应该有少量的超声凝胶擦到自己的胸部前余下的超声凝胶应用，以提高耦合。降低成像探针和成像平台的角度调整，以获得最佳的胸骨旁左室长轴。不调整探头的角度，都将丢失，因为针对齐。 </li><li>同时监测超声屏幕上LV的形象，慢慢推进针，直到它是探头的底部附近。调整针和探头的位置，如有必要，纠正对齐转变。轻轻用生理盐水冲洗针。开始录制压力数据和为零的与LabChart软件的压力传感器。传感器的漂移，温度和位置，所以重要的是它只是之前测量每个鼠标的压力为零。 </li><li>慢慢地前进针，直到它可以在超声图像边缘，但不是在LV尚未。调整针的位置，如有必要，在进入的LV顶点。调整探头位置，如有必要，保持针的清晰图像。推进到LV流明（图3）针，而压力数据记录和监控的超声图像上的针位置。从压力传感器开始搏动录音证实管腔内的LV（图4）的位置。 </li><li>如果针出现在LV腔，但不脉动压力的录音，用注射器的柱塞上的光自来水冲洗，直到压力增加（约5 - 10μL的体积）检测。这应该清除任何阻塞，可能会阻止一个准确的读数。如果压力读数仍然没有搏动，针头可能高于或低于正确的平面和不被插入到LV腔。缩回针头，用生理盐水，并提前再次刷新。如果搏动的读数仍然没有得到，移动到下一个鼠标。每个鼠标使用一种新的针。 </li><li>成功的压力读数可从75％胚胎和新生小鼠的企图。读数应采取5 - 10分钟和鼠标的压力数据不应包括心跳率比预期有显着不同（图5A）。心率有显着影响心血管措施和心跳率的改变指示心脏窘迫的。胚胎窘迫通常发生在1 - 1.5小时后，第一个外在的子宫，所以速度是重要的，用于测量压力，在整个产仔。 </li></ol> 4。代表结果结果表明C57BL6J小鼠。在LV流明的图像如图3所示的P1鼠标针。针是必要的胸壁穿刺和获得LV的小管腔，但它显着增加的压力系统的响应时间。当近似压力逐步增加手动应用到系统中，时间达到67％的最大压力是0.067 SEc配合油管（最有可能的实时应用的压力步骤指示），0.105秒与25的的Ğ针和0.529秒与30克针。完整的描图4A和4C所示，可以看出在延迟达到最大压力。虽然响应时间慢的30G针，更好地捕获波形在胚胎和新生儿早期阶段，因为心率增加小鼠5岁。尽管这个限制，收缩压可以计算假设，真正的舒张（最小）的压力是零，和收缩压（最高）低压压力是两次平均LV压力，处于稳定状态的读数（图4B和4D确定）6。人们普遍认为，收缩期LV和动脉压力是相等的。如图5所示测量心率，并计算LV的E18和P14之间的不同年龄段的压力。 <img src="/files/ftp_upload/3756/3756fig1.jpg" /> 图1。连接三通旋塞，男（M）和女性（F）的鲁尔锁连接，软管倒钩，油管，注射器和针头的压力传感器的图像。 <img src="/files/ftp_upload/3756/3756fig2.jpg" /> 图2图像的设立成像探测（一）配合针。成像平台是LV尖，使鼠标正面临着注射手臂的旋转。探头安装在可调的立场，在必要的大致方向，以获得一个LV长轴图像。针管套管安装在注射的手臂。针推进到一个超声波凝胶丘上的成像平台，以确定适当的角度，以尊重成像探测（二）垂直和水平位置。 <img src="/files/ftp_upload/3756/3756fig3.jpg" /> 图3。针（N）的图像通过先进的胸壁（连续）到LV在P1鼠标流明。比例尺= 0.1毫米。 <img src="/files/ftp_upload/3756/3756fig4.jpg" /> 图4。范例脉动压力读数针进入LV的E18（一）和P14（三）鼠标。有一个在达到一个稳定的状态，由于针连接系统的响应时间延迟。在稳定状态的读数放大视图显示在B和D注最低E18低压压力接近零，但完整的波形从零到最大压力不能被记录在P14的小鼠的心跳率较高。平均压力测量稳态读数，假设LV收缩压= 2×平均压力。 <img src="/files/ftp_upload/3756/3756fig5.jpg" /> 图5测量心跳率（A）和计算收缩期左室压力（B）为E18 - P14的小鼠。 n = P3的，E18，P1，22 5 7 23 P7和P14的16 <suP&gt; 5-7。

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没有利益冲突的声明。

这里介绍的协议提供了一个LV的压力，在后期的胚胎和新生儿早期小鼠的测量方法。该协议的主要限制是压力系统的时间分辨率。压力信号衰减，因为它从LV旅行通过针传感器，不仅意味着可以记录压力值。最小的阻​​尼可以通过使用尽可能最大的针，但针必须在LV流明，适合不同年龄的小鼠。因为舒张压可近似为零，LV因此动脉收缩压，可以计算平均LV压力测量。虽然额外动脉变量将是理想的（...

<table border="1"><tbody><tr><td> 试剂/设备名称 </td><td> 公司 </td><td> 目录编号 </td><td> 评论 </td></tr><tr><td>高分辨率超声系统</td><td> visualsonics </td><td> VEVO 770 </td><td>或其他适当的超声系统</td></tr><tr><td>高频超声探头</td><td> visualsonics </td><td> 708和707B </td><td></td></tr><tr><td>成像平台和注射手臂</td><td> visualsonics </td><td>成像站2 </td><td>心电图和温度反馈控制平台</td></tr><tr><td>压力传感器</td><td>公元仪器</td><td> MLT 844 </td><td></td></tr><tr><td>桥式放大器</td><td>公元仪器</td><td> ML221 </td><td></td></tr><tr><td>数据采集​​系统</tD&gt; <td>公元仪器</td><td> ML866 </td><td></td></tr><tr><td>数据记录软件</td><td>公元仪器</td><td> LabChart </td><td></td></tr><tr><td>环站和钳</td><td>各供应商</td><td></td><td>在测量过程中要保持压力传感器</td></tr><tr><td>三路活塞，带Luer连接，男性锁</td><td>科尔帕默</td><td> 30600-02 </td><td></td></tr><tr><td> 1/16“编号聚乙烯管材</td><td>科尔帕默</td><td> 06408 </td><td></td></tr><tr><td>男性和女性luers W / 1/16“软管倒刺</td><td>科尔帕默</td><td> 45510-50 45510-00 </td><td></td></tr><tr><td> 24“在每年年底与男性和女性的鲁尔油管</td><td>科尔帕默</td><td> 30600-60 </td><td></td></tr><tr><td> 3日和10毫升的注射器</td><td> BD公司</td><td></td><td></td></tr><tr><td> 30和25G的针头</td><td> BD公司</td><td></td><td> 1.5英寸长</td></tr><tr><td>大本钟压力计</td><td>里斯特</td><td> 1456-100 </td><td></td></tr><tr><td>盐水</td><td>各供应商</td><td></td><td></td></tr><tr><td>肝素</td><td>各供应商</td><td></td><td></td></tr><tr><td>超声凝胶</td><td>帕克</td><td> aquasonic 100 </td><td></td></tr><tr><td>头发卸妆乳液</td><td>奈尔</td><td></td><td></td></tr></tbody></table>

measuring left ventricular pressure in late embryonic and neonatal mice

血压显着增加脊椎动物​​在胚胎和出生后的发展。在小鼠，血流量首先是围绕胚胎一天（五）8.5 1检测。收缩期左心室（LV）压力是E9.5在2毫米汞柱和11毫米汞柱在E14.5 2。在这些中期萌芽阶段，LV是清晰可见，通过创血压测量胸壁肋骨和皮肤，因为没有得到充分的开发。在E14.5和出生（约E21号）的成像方法必须使用查看LV。出生后，平均动脉压力增大30 - 35 3 - 70毫米汞柱从产后天（P）2。超越P20的，可以测量血压与固态导管（即米勒或Scisense）。 P20的之前，这些导管有太大发展小鼠动脉和动脉血压测量必须用自定义拉塑料导管连接到充液压力传感器或玻璃micropipettes ATT痛伺服空压力传感器4。 我们最近的工作表明，血压增幅最大的中后期早在产后5-7小鼠胚胎发生。这种血压的大量增加，可能会影响发展的动脉平滑肌细胞（SMC）的表型和触发重要的机械传导事件。在人类疾病，地方发展动脉的性能是在细胞外基质蛋白（即马凡氏的综合症8和主动脉瓣上狭窄9）的缺陷损害血压，在此期间迅速变化可能有助于疾病的表型和严重程度通过在机械传导的改变信号。因此，重要的是要能够测量血压的变化，人类疾病的小鼠模型中后期胚胎和新生儿时期。 我们描述了在后期测量左室压力的方法胚胎（E18）和产后早期（小 - 20）小鼠。超声引导下，一个充满液体的压力传感器连接到一个针插入的LV。护理是采取维持正常的心脏功能，尤其是在实验协议的小鼠胚胎。有代表性的数据提出并讨论了该协议的限制。

Watch this Scientific Journal Video about Measuring Left Ventricular Pressure in Late Embryonic and Neonatal Mice at JoVE.com

Measuring Left Ventricular Pressure in Late Embryonic and Neonatal Mice

测量左室压力在胚胎和新生小鼠（LV）的描述。压力测量插入到LV连接到一个充满液体的传感器，超声引导下针。必须小心维持正常的心脏功能，在实验协议。

测量中晚期胚胎和新生小鼠左心室压力

Blood pressure increases significantly during embryonic and postnatal development in vertebrate animals. In the mouse, blood flow is first detectable ...

measuring-left-ventricular-pressure-late-embryonic-neonatal

Research

JoVE Journal

Bioengineering

13.8K 次观看.  Saint Louis University. 测量左室压力在胚胎和新生小鼠（LV）的描述。压力测量插入到LV连接到一个充满液体的传感器，超声引导下针。必须小心维持正常的心脏功能，在实验协议。

视频: Measuring Left Ventricular Pressure in Late Embryonic and Neonatal Mice

Measuring and Modeling Contractile Drying in Human Stratum Corneum

Stratum corneum (SC) is the most superficial skin layer. Its contact with the external environment means that this tissue layer is subjected to both cleansing agents and daily variations in ambient moisture; both of which can alter the water content of the tissue. Reductions in water content from severe barrier dysfunction or low humidity environments can alter SC stiffness and cause a build-up of drying stresses. In extreme conditions, these factors can cause mechanical rupture of the tissue. We have established a high throughput method of quantifying dynamic changes in the mechanical properties of SC upon drying. This technique can be employed to quantify changes in the drying behavior and mechanical properties of SC with cosmetic cleanser and moisturizer treatments. This is achieved by measuring dynamic variations in spatially resolved in-plane drying displacements of circular tissue samples adhered to an elastomer substrate. In-plane radial displacements acquired during drying are azimuthally averaged and fitted with a profile based on a linear elastic contractility model. Dynamic changes in drying stress and SC elastic modulus can then be extracted from the fitted model profiles.

This article describes a method of quantifying the dynamic drying behavior and mechanical properties of stratum corneum by measuring spatially resolved in-plane drying displacements of circular tissue samples adhered to an elastomer substrate. This technique can be used to measure how different chemical treatments alter drying and tissue mechanical properties.

测量与建模干燥收缩人类角质层

Stratum corneum (SC) is the most superficial skin layer. Its contact with the external environment means that this tissue layer is subjected to both ...

科研

生物工程

Ammonia Synthesis at Low Pressure

Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in areas requiring ammonia for synthetic fertilizer. Such wind energy is often called &#34;stranded,&#34; because it is only available far from population centers where it can be directly used.
In the proposed low pressure process, nitrogen is made from air using pressure swing absorption, and hydrogen is produced by electrolysis of water. While these gases can react at approximately 400 &#176;C in the presence of a promoted conventional catalyst, the conversion is often limited by the reverse reaction, which makes this reaction only feasible at high pressures. This limitation can be removed by absorption on an ammine-like calcium or magnesium chloride. Such alkaline metal halides can effectively remove ammonia, thus suppressing the equilibrium constraints of the reaction. In the proposed absorption-enhanced ammonia synthesis process, the rate of reaction may then be controlled not by the chemical kinetics nor the absorption rates, but by the rate of the recycle of unreacted gases. The results compare favorably with ammonia made from a conventional small scale Haber-Bosch process.

Ammonia can be synthesized at low pressure by using a conventional catalyst and an ammonia selective absorbent.

低压氨合成

Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in ...

Anatomically Realistic Neonatal Heart Model for Use in Neonatal Patient Simulators

Neonatal patient simulators (NPS) are artificial patient surrogates used in the context of medical simulation training. Neonatologists and nursing staff practice clinical interventions such as chest compressions to ensure patient survival in the case of bradycardia or cardiac arrest. The simulators used currently are of low physical fidelity and therefore cannot provide qualitative insight into the procedure of chest compressions. The embedding of an anatomically realistic heart model in future simulators enables the detection of cardiac output generated during chest compressions; this can provide clinicians with an output parameter, which can deepen the understanding of the effect of the compressions in relation to the amount of blood flow generated. Before this monitoring can be achieved, an anatomically realistic heart model must be created containing: two atria, two ventricles, four heart valves, pulmonary veins and arteries, and systemic veins and arteries. This protocol describes the procedure for creating such a functional artificial neonatal heart model by utilizing a combination of magnetic resonance imaging (MRI), 3D printing, and casting in the form of cold injection molding. Using this method with flexible 3D printed inner molds in the injection molding process, an anatomically realistic heart model can be obtained.

This protocol describes a procedure for creating functional artificial neonatal heart models by utilizing a combination of magnetic resonance imaging, 3D printing, and injection molding. The purpose of these models is for integration into the next generation of neonatal patient simulators and as a tool for physiological and anatomical studies.

在新生儿患者模拟器中使用的解剖现实新生儿心脏模型

Neonatal patient simulators (NPS) are artificial patient surrogates used in the context of medical simulation training. Neonatologists and nursing staff ...

Mouse Model of Pressure Ulcers After Spinal Cord Injury

Pressure ulcers (PUs) are common debilitating complications of traumatic spinal cord injury (SCI) and tend to occur in soft tissues around bony prominences. There is, however, little known about the impact of SCI on skin wound healing in the context of animal models in controlled experimental settings. In this study, a simple, non-invasive, reproducible and clinically relevant mouse model of PUs in the context of complete SCI is presented. Adult male mice (Balb/c, 10 weeks old) were shaved and depilated. Post-depilation (24 h), mice were subjected to laminectomy followed by complete spinal cord transection (T9-T10 vertebrae). Immediately after, a skin fold on the back of the mice was lifted and sandwiched between two magnetic discs held in place for next 12 h, thus creating an ischemic area that developed into a PU over the following days. The wounded areas demonstrated tissue edema and epidermal disappearance by day 3 post-magnet application. PUs spontaneously developed and healed. Healing was, however, slower in the SCI mice compared to control non-SCI mice when the wound was created below the level of SCI. Conversely, no difference in healing was seen between SCI and control non-SCI mice when the wound was created above the level of SCI. This model is a potentially useful tool to study the dynamics of skin PU development and healing after SCI, as well as to test therapeutic approaches that may help heal such wounds.

Here, we describe a simple method to induce clinically relevant skin pressure ulcers (PUs) in a mouse model of spinal cord injury (SCI). This model can be used in pre-clinical studies to screen for different therapeutics for healing PUs in SCI patients.

脊髓损伤后压力溃疡的小鼠模型

Pressure ulcers (PUs) are common debilitating complications of traumatic spinal cord injury (SCI) and tend to occur in soft tissues around bony ...

Measuring Global Cellular Matrix Metalloproteinase and Metabolic Activity in 3D Hydrogels

Three-dimensional (3D) cell culture systems often more closely recapitulate in vivo cellular responses and functions than traditional two-dimensional (2D) culture systems. However, measurement of cell function in 3D culture is often more challenging. Many biological assays require retrieval of cellular material which can be difficult in 3D cultures. One way to address this challenge is to develop new materials that enable measurement of cell function within the material. Here, a method is presented for measurement of cellular matrix metalloproteinase (MMP) activity in 3D hydrogels in a 96-well format. In this system, a poly(ethylene glycol) (PEG) hydrogel is functionalized with a fluorogenic MMP cleavable sensor. Cellular MMP activity is proportional to fluorescence intensity and can be measured with a standard microplate reader. Miniaturization of this assay to a 96-well format reduced the time required for experimental set up by 50% and reagent usage by 80% per condition as compared to the previous 24-well version of the assay. This assay is also compatible with other measurements of cellular function. For example, a metabolic activity assay is demonstrated here, which can be conducted simultaneously with MMP activity measurements within the same hydrogel. The assay is demonstrated with human melanoma cells encapsulated across a range of cell seeding densities to determine the appropriate encapsulation density for the working range of the assay. After 24 h of cell encapsulation, MMP and metabolic activity readouts were proportional to cell seeding density. While the assay is demonstrated here with one fluorogenic degradable substrate, the assay and methodology could be adapted for a wide variety of hydrogel systems and other fluorescent sensors. Such an assay provides a practical, efficient and easily accessible 3D culturing platform for a wide variety of applications.

Here, a protocol is presented for encapsulating and culturing cells in poly(ethylene glycol) (PEG) hydrogels functionalized with a fluorogenic matrix metalloproteinase (MMP)-degradable peptide. Cellular MMP and metabolic activity are measured directly from the hydrogel cultures using a standard microplate reader.

三维水凝胶中全球细胞基质金属蛋白酶和代谢活性的测定

Three-dimensional (3D) cell culture systems often more closely recapitulate in vivo cellular responses and functions than traditional two-dimensional (2D) ...

Methods for In Vivo Biomechanical Testing on Brachial Plexus in Neonatal Piglets

Neonatal brachial plexus palsy (NBPP) is a stretch injury that occurs during the birthing process in nerve complexes located in the neck and shoulder regions, collectively referred to as the brachial plexus (BP). Despite recent advances in obstetrical care, the problem of NBPP continues to be a global health burden with an incidence of 1.5 cases per 1,000 live births. More severe types of this injury can cause permanent paralysis of the arm from the shoulder down. Prevention and treatment of NBPP warrants an understanding of the biomechanical and physiological responses of newborn BP nerves when subjected to stretch. Current knowledge of the newborn BP is extrapolated from adult animal or cadaveric BP tissue instead of in vivo neonatal BP tissue. This study describes an in vivo mechanical testing device and procedure to conduct in vivo biomechanical testing in neonatal piglets. The device consists of a clamp, actuator, load cell, and camera system that apply and monitor in vivo strains and loads until failure. The camera system also allows monitoring of the failure location during rupture. Overall, the presented method allows for a detailed biomechanical characterization of neonatal BP when subjected to stretch.

Methods for In Vivo Biomechanical Testing on Brachial Plexus in Neonatal Piglets

Presented here are methods to perform in vivo biomechanical testing on brachial plexus in a neonatal piglet model.

新生儿小猪体内胸腺菌的活体力学试验方法

Neonatal brachial plexus palsy (NBPP) is a stretch injury that occurs during the birthing process in nerve complexes located in the neck and shoulder ...

Optical Imaging of Isolated Murine Ventricular Myocytes

The ability to isolate adult cardiac myocytes has permitted researchers to study a variety of cardiac pathologies at the single cell level. While advances in calcium sensitive dyes have permitted the robust optical recording of single cell calcium dynamics, recording of robust transmembrane optical voltage signals has remained difficult. Arguably, this is because of the low single to noise ratio, phototoxicity, and photobleaching of traditional potentiometric dyes. Therefore, single cell voltage measurements have long been confined to the patch clamp technique which while the gold standard, is technically demanding and low throughput. However, with the development of novel potentiometric dyes, large, fast optical responses to changes in voltage can be obtained with little to no phototoxicity and photobleaching. This protocol describes in detail how to isolate adult murine myocytes which can be used for cellular shortening, calcium, and optical voltage measurements. Specifically, the protocol describes how to use a ratiometric calcium dye, a single-excitation calcium dye, and a single excitation voltage dye. This approach can be used to assess the cardiotoxicity and arrhythmogenicity of various chemical agents. While phototoxicity is still an issue at the single cell level, methodology is discussed on how to reduce it.

We present the methodology for the isolation of murine myocytes and how to obtain voltage or calcium traces simultaneously with sarcomere shortening traces using fluorescence photometry with simultaneous digital cell geometry measurements.

分离的月毛心室肌细胞的光学成像

The ability to isolate adult cardiac myocytes has permitted researchers to study a variety of cardiac pathologies at the single cell level. While advances ...

Patterning the Geometry of Human Embryonic Stem Cell Colonies on Compliant Substrates to Control Tissue-Level Mechanics

Human embryonic stem cells demonstrate a unique ability to respond to morphogens in vitro by self-organizing patterns of cell fate specification that correspond to primary germ layer formation during embryogenesis. Thus, these cells represent a powerful tool with which to examine the mechanisms that drive early human development. We have developed a method to culture human embryonic stem cells in confined colonies on compliant substrates that provides control over both the geometry of the colonies and their mechanical environment in order to recapitulate the physical parameters that underlie embryogenesis. The key feature of this method is the ability to generate polyacrylamide hydrogels with defined patterns of extracellular matrix ligand at the surface to promote cell attachment. This is achieved by fabricating stencils with the desired geometric patterns, using these stencils to create patterns of extracellular matrix ligand on glass coverslips, and transferring these patterns to polyacrylamide hydrogels during polymerization. This method is also compatible with traction force microscopy, allowing the user to measure and map the distribution of cell-generated forces within the confined colonies. In combination with standard biochemical assays, these measurements can be used to examine the role mechanical cues play in fate specification and morphogenesis during early human development.

Extracellular matrix ligands can be patterned onto polyacrylamide hydrogels to enable the culture of human embryonic stem cells in confined colonies on compliant substrates. This method can be combined with traction force microscopy and biochemical assays to examine the interplay between tissue geometry, cell-generated forces, and fate specification.

在符合标准的基质上对人类胚胎干细胞菌落的几何结构进行模式化，以控制组织级力学

Human embryonic stem cells demonstrate a unique ability to respond to morphogens in vitro by self-organizing patterns of cell fate specification that ...

Evaluation of Left Ventricular Structure and Function using 3D Echocardiography

Three-dimensional (3D) quantification of the left ventricle (LV) provides significant added value in terms of diagnostic accuracy and precise risk stratification in various cardiac disorders. Recently, 3D echocardiography became available in routine cardiology practice; however, high-quality image acquisition and subsequent analysis have a steep learning curve. The present article aims to guide the reader through a detailed 3D protocol by presenting tips and tricks and also by highlighting the potential pitfalls to facilitate the widespread but technically sound use of this important technique concerning the LV. First and foremost, we show the acquisition of a high-quality 3D dataset with optimal spatial and temporal resolution. Then, we present the analytical steps toward a detailed quantification of the LV by using one of the most widely applied built-in software. We will quantify LV volumes, sphericity, mass and also systolic function by measuring ejection fraction and myocardial deformation (longitudinal and circumferential strain). We will discuss and provide clinical examples about the essential scenarios where the transition from a conventional echocardiographic approach to a 3D-based quantification is highly recommended.

In this article, we provide a step-by-step acquisition and analysis protocol for the volumetric assessment and speckle-tracking analysis of the left ventricle by 3D echocardiography, particularly focusing on practical aspects that maximize the feasibility of this technique.

使用3D超声心动图评估左心室结构和功能

Three-dimensional (3D) quantification of the left ventricle (LV) provides significant added value in terms of diagnostic accuracy and precise risk ...

Measuring 3D In-vivo Shoulder Kinematics using Biplanar Videoradiography

The shoulder is one of the human body's most complex joint systems, with motion occurring through the coordinated actions of four individual joints, multiple ligaments, and approximately 20 muscles. Unfortunately, shoulder pathologies (e.g., rotator cuff tears, joint dislocations, arthritis) are common, resulting in substantial pain, disability, and decreased quality of life. The specific etiology for many of these pathologic conditions is not fully understood, but it is generally accepted that shoulder pathology is often associated with altered joint motion. Unfortunately, measuring shoulder motion with the necessary level of accuracy to investigate motion-based hypotheses is not trivial. However, radiographic-based motion measurement techniques have provided the advancement necessary to investigate motion-based hypotheses and provide a mechanistic understanding of shoulder function. Thus, the purpose of this article is to describe the approaches for measuring shoulder motion using a custom biplanar videoradiography system. The specific objectives of this article are to describe the protocols to acquire biplanar videoradiographic images of the shoulder complex, acquire CT scans, develop 3D bone models, locate anatomical landmarks, track the position and orientation of the humerus, scapula, and torso from the biplanar radiographic images, and calculate the kinematic outcome measures. In addition, the article will describe special considerations unique to the shoulder when measuring joint kinematics using this approach.

Biplane videoradiography can quantify shoulder kinematics with a high degree of accuracy. The protocol described herein was specifically designed to track the scapula, humerus, and the ribs during planar humeral elevation, and outlines the procedures for data collection, processing, and analysis. Unique considerations for data collection are also described.

使用双平面影像学测量 3D 体内肩部运动学

The shoulder is one of the human body's most complex joint systems, with motion occurring through the coordinated actions of four individual joints, ...