This work was supported by the National Institutes of Health (R01-EB014496). The authors would like to thank Iason Apostolakis for his contribution to the experiments.

该协议被批准哥伦比亚大学的机构动物护理和使用委员会。所有的数据采集和处理用Matlab环境执行。 1.实验装置<ol><li>在90分钟的脱气离体犬肝脏样本。把肝脏样品中的填充有脱气磷酸盐缓冲溶液（ 图1）罐。固定在一个声吸收用针在肝脏的四肢的肝样品。 </li><li>通过一个圆孔位于93元半球阵列HIFU换能器（治疗）的中心，在4.5 MHz的中心频率的70 mm焦距的深度和插入64元0.32毫米间距，2.5 MHz的中心频率相控阵（成像） 1.7毫米×0毫米焦距的大小11。对齐两个传感器同轴和修复成像传感器到治疗换能器的调整螺丝。 <ol><li>盖上HIFU换能器与AVolume控制聚氨酯膜填充有流动的脱气的水来冷却下来。安装在一个计算机控制的3-D定位的换能器组件。 </li></ol></li><li>的HIFU换能器连接到功能发生器发送具有500毫伏最大振幅为25赫兹的调幅正弦波形。成像传感器连接到使用Matlab软件完全可编程超声系统。 注意：用超声系统相关联的软件和利用Matlab环境必须连接到系统中的计算机上。将50 dB的RF放大器和匹配网络应当放置在HIFU换能器与函数发生器分别放大功率并匹配的阻抗之间。 </li><li>创建一个极性的网格，用Matlab，开始从阵​​列的表面50毫米和40毫米深的在径向方向上具有9.625微米，90°，128线和哪些原点的空间的步骤在方位角方向是FOCUS发散波。限定的发散的波10.24毫米源（孔径大小的一半）的阵列的表面的后面，并集中在横向方向上。 <ol><li>创建一个笛卡尔网格，用Matlab，开始从阵​​列的表面50毫米和40毫米深在与9.625微米，宽20毫米，与64线，为平面波的左右方向的空间的步骤的轴向方向。限定所述阵列的表面上的平面波的来源。对于每一个网格，计算从源的时间的每个点的网格和背面到阵列中的每个元素。 </li></ol></li><li>输入“ReconMat_DW”的发散波成像或“ReconMat_PW”在MATLAB命令窗口平面波成像，然后按“Enter”来创建一个标准的延迟与求和算法，每个网格相关的​​重建矩阵。申请延迟与求和算法的标准基础的每个矢量和检索所述非零点的Elemen所得矩阵 11的TS。分配从所得矩阵获得的稀疏矩阵的相应位置中的非零元素。保存在电脑硬盘上的重建矩阵。 注意：发散和平面波的方法使用两个不同的重建矩阵。 <ol><li>铸造重建矩阵到GPU矩阵。输入“SetUpP4_2Flash_4B_streaming_DW”的发散波成像或“SetUpP4_2Flash_4B_streaming_PW”在Matlab的命令窗口，然后按“Enter”来创建使用相控阵由制造商相关的并脚本超声通道数据采集设置文件平面波成像的超声系统。命名安装文件“P4-2Flash_DivergingWave.mat”的发散波成像和“P4-2Flash_PlaneWave.mat”的平面波成像。 注：商业软件包，必须在电脑•安装Ø投重建稀疏矩阵到GPU矩阵。 </li></ol></li><li>使高帧速率的超声数据采集的肝脏开始同时作为HIFU超声系统使用外部触发函数发生器同步。 </li><li>打开Matlab的。运行安装脚本“SetUpP4_2Flash_4B.m”由超声系统制造商使用B模式成像提供。命名创建的安装文件：“P4-2Flash_4B_Bmode.mat”。使用“VSX”命令，在“.MAT文件要处理的名称：”提示，输入安装文件“P4-2Flash_4B_Bmode.mat”的名称。移动这两个换能器，并使用B模式显示该出现在计算机屏幕上，以它们在肝脏消融的目标区域放置。目标的区域中的肝脏表面下大约1cm，以避免高超声波衰减因吸收。保存在计算机上的肝脏的常规B模式图像。 注意：在这里，我们两个肝标本进行高强度聚焦超声消融在11个不同的位置通过移动换能器与所述3D定位器为每个消融。 </li></ol> 2.超声数据采集<ol><li>打开Matlab的。使用“VSX”命令，在“.MAT文件要处理的名称：”提示，输入安装文件“P4-2Flash_DivergingWave.mat”的名称发散波成像或“P4-2Flash_PlaneWave.mat”的平面波成像。启动HIFU和2分钟的目标区域中应用它。 </li><li>在使用发散波2分钟收购以每秒1000帧的RF信道的数据。另外，在2分钟利用平面波收购以每秒1000帧的RF信道的数据。 </li><li>通过PCI特快电缆将数据传输到主计算机每200帧。或者，对于实时流，使用平面波和TRANSF期间2分钟获取以每秒167帧的RF信道的数据器中的数据到主计算机的每2帧。 注：带套200帧的成像方法提供了每套之间的每个设置，但创造的间隙内高时间分辨率，适用于离线处理。在167 fps的影像处理方法具有较低的时间分辨率，但不创建整个消融时间的任何间隙，并且非常适合实时流。 </li><li>铸造RF信道的数据矩阵与Matlab的单精度GPU矩阵。由重建矩阵相乘RF信道的数据矩阵，以获得重建的RF数据11。 </li></ol> 3.排量成像<ol><li>创建一个6 阶 Butterworth低通于4 MHz的截止频率利用Matlab的DSP系统工具箱过滤器。应用此低通滤波器，以重构RF数据来过滤掉4.5兆赫HIFU组件。 </li><li>估计使用一维归一化互相关的连续帧之间的轴向位移用3.1毫米窗口长度和90％的重叠。 </li><li>创建一个6 阶 Butterworth低通在100赫兹的截止频率利用Matlab的DSP系统工具箱过滤器。用Matlab检索50赫兹振荡频率分量应用此低通滤波器的时间位移的数据。 </li><li>定义感兴趣区域（ROI）的区域作为在-6分贝焦点区域（1.7×0.4毫米，在水中）和位于70毫米背离换能器表面。在提取该ROI的位移数据。消融2分钟作为平均位移和在ROI的位移的标准偏差之间的比率后估计在焦点区域中的位移信噪比（SNR d）所示。 </li><li>提取50赫兹时间位移信号在从位移矩阵数据的焦点。时间位移信号转换的重点放到利用Matlab可听见的声音。 </li></ol>

<ol>
	<li>Al-Bataineh, O., Jenne, J., Huber, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+and+future+applications+of+high+intensity+focused+ultrasound+in+cancer.">Clinical and future applications of high intensity focused ultrasound in cancer.</a> Cancer Treat Rev. 38, 346-353 (2012).</li><li>Dewhirst, M. W., Viglianti, B. L., Lora-Michiels, M., Hanson, M., Hoopes, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Basic+principles+of+thermal+dosimetry+and+thermal+thresholds+for+tissue+damage+from+hyperthermia.">Basic principles of thermal dosimetry and thermal thresholds for tissue damage from hyperthermia.</a> Int J Hyperthermia. 19, 267-294 (2003).</li><li>Napoli, A., 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=MR-guided+high-intensity+focused+ultrasound:+current+status+of+an+emerging+technology.">MR-guided high-intensity focused ultrasound: current status of an emerging technology.</a> Cardiovasc Intervent Radiol. 36, 1190-1203 (2013).</li><li>Gudur, M. S., Kumon, R. E., Zhou, Y., Deng, C. X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-frequency+rapid+B-mode+ultrasound+imaging+for+real-time+monitoring+of+lesion+formation+and+gas+body+activity+during+high-intensity+focused+ultrasound+ablation.">High-frequency rapid B-mode ultrasound imaging for real-time monitoring of lesion formation and gas body activity during high-intensity focused ultrasound ablation.</a> IEEE Trans Ultrason Ferroelectr Freq Control. 59, 1687-1699 (2012).</li><li>Jensen, C. R., Cleveland, R. O., Coussios, C. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real-time+temperature+estimation+and+monitoring+of+HIFU+ablation+through+a+combined+modeling+and+passive+acoustic+mapping+approach.">Real-time temperature estimation and monitoring of HIFU ablation through a combined modeling and passive acoustic mapping approach.</a> Phys Med Biol. 58, 5833-5850 (2013).</li><li>Mariani, A., 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=Real+time+shear+waves+elastography+monitoring+of+thermal+ablation:+in+vivo+evaluation+in+pig+livers.">Real time shear waves elastography monitoring of thermal ablation: in vivo evaluation in pig livers.</a> J Surg Res. 188, 37-43 (2014).</li><li>Bing, K. F., Rouze, N. C., Palmeri, M. L., Rotemberg, V. M., Nightingale, K. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combined+ultrasonic+thermal+ablation+with+interleaved+ARFI+image+monitoring+using+a+single+diagnostic+curvilinear+array:+a+feasibility+study.">Combined ultrasonic thermal ablation with interleaved ARFI image monitoring using a single diagnostic curvilinear array: a feasibility study.</a> Ultrason Imaging. 33, 217-232 (2011).</li><li>Athanasiou, A., 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=Breast+lesions:+quantitative+elastography+with+supersonic+shear+imaging--preliminary+results.,+Radiology.">Breast lesions: quantitative elastography with supersonic shear imaging--preliminary results., Radiology.</a> 256, 297-303 (2010).</li><li>Maleke, C., Konofagou, E. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Harmonic+motion+imaging+for+focused+ultrasound+(HMIFU):+a+fully+integrated+technique+for+sonication+and+monitoring+of+thermal+ablation+in+tissues.">Harmonic motion imaging for focused ultrasound (HMIFU): a fully integrated technique for sonication and monitoring of thermal ablation in tissues.</a> Phys Med Biol. 53, 1773-1793 (2008).</li><li>Maleke, C., Konofagou, E. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+feasibility+of+real-time+monitoring+of+focused+ultrasound+surgery+(FUS)+using+harmonic+motion+imaging+(HMI).">In vivo feasibility of real-time monitoring of focused ultrasound surgery (FUS) using harmonic motion imaging (HMI).</a> IEEE Trans Biomed Eng. 57, 7-11 (2010).</li><li>Hou, G. Y., 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=Sparse+matrix+beamforming+and+image+reconstruction+for+2-D+HIFU+monitoring+using+harmonic+motion+imaging+for+focused+ultrasound+(HMIFU)+with+in+vitro+validation.">Sparse matrix beamforming and image reconstruction for 2-D HIFU monitoring using harmonic motion imaging for focused ultrasound (HMIFU) with in vitro validation.</a> IEEE Trans Med Imaging. 33, 2107-2117 (2014).</li></ol>

The authors declare that they have no competing financial interests.

HIFU病变的实时监控是非常重要的，以确保适当和有效的病变交付。作为病变形式中，组织变硬和下激励它的运动幅度减小。施加在HIFU的组织的结果的区域中诱导组织位移的声辐射力。在位移的相对变化是组织硬度相对变化的替代。这种技术提供监测HIFU病变不停止在与其它超声基础的方法治疗的优点。在这项研究中（4.5赫兹）的实时监测的时间分辨率比在MR引导HIFU消融（1赫兹）中获得更高。 ...

High Intensity Focused Ultrasound (HIFU) is a technique that generates temperature elevation at the focal region and can be used to ablate cancerous tissue 1. Temperature elevation at the focus causes thermal lesions in the tissue 2. In order to avoid overtreating a region and to reduce treatment duration, it is imperative to reliably monitor the ablation. Magnetic resonance-guided focused ultrasound (MRgFUS) is the main technique used in clinic to guide and monitor HIFU treatment 3. MRI provides high spatial resolution images of the treated region with tissue displacement or thermal dose but has a frame rate of 0.1-1 Hz and is costly. Several ultrasound-based techniques such as B-mode imaging 4, passive acoustic mapping 5, shear wave imaging 6 and acoustic radiation force impulse 7 have been developed to guide and monitor thermal ablation. However, B-mode imaging and passive acoustic mapping do not provide imaging of mechanical properties of the ablated region which is useful to the operator to improve lesion delivery. 
Shear wave imaging and acoustic radiation force impulse can both characterize the elasticity of the tissue by measuring acoustic radiation force-induced displacements 7,8. However, in both methods, the HIFU treatment is typically interrupted to monitor the ablation. Our group has developed a technique called Harmonic Motion Imaging for Focus Ultrasound (HMIFU) which can monitor the HIFU treatment with ultrasound without stopping the ablation9,10. Briefly, a HIFU transducer sends an amplitude-modulated wave to the region to ablate while simultaneously generating an oscillatory motion in the focal region. A co-axially aligned ultrasound transducer is used to image this oscillation. The magnitude of the induced motion is related to the stiffness of the tissue.
To ensure proper lesion delivery, the temporal resolution of real-time monitoring is of key interest in ablation guidance. Recently, our group has shown real-time streaming of displacement at a frame rate up to 15 Hz, imaged with diverging waves in a narrow field of view and using a fast image reconstruction method 11. Several beamforming techniques can be used to image the displacements. A large field of view can be obtained with diverging wave imaging by changing the delay profile but the axial direction is not aligned with the HIFU beam on the lateral regions and the wave is attenuated due to geometric spreading in the lateral direction, which can affect the quality of the displacement estimation. In contrast, the lateral field of view for plane wave is upper bounded by the active aperture but the axial direction is aligned with the HIFU beam at the focus and there is no geometric spreading in the lateral direction. Depending on the type of application, one or the other imaging method can be selected. The objectives of this protocol are to show how plane wave imaging can provide real-time streaming of displacements images using HMIFU during ablation and to compare the quality of the motion estimation between diverging and plane wave imaging.

<table border="0" cellpadding="0" cellspacing="0">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr>
			<td>P4-2 Phased array</td>
			<td>ATL</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>H-178 HIFU transducer</td>
			<td>Sonic Concepts</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>3-D positioner</td>
			<td>Velmex Inc.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>AT33522A function generator</td>
			<td>Agilent Technologies</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>V-1 ultrasound system</td>
			<td>Verasonics</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>3100L RF amplifier</td>
			<td>ENI</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Matching network</td>
			<td>Sonic Concepts</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Degasing system</td>
			<td>Sonic Concepts</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Programming software</td>
			<td>Matlab</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Jacket software package</td>
			<td>Accelereyes</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

real-time monitoring of high intensity focused ultrasound (hifu) ablation of in vitro canine livers using harmonic motion imaging for focused ultrasound (hmifu)

谐运动成像的聚焦超声（HMIFU）是可以执行和监控高强度聚焦超声（HIFU）消融的技术。的振荡运动在一个93元件和4.5兆赫中心频率的HIFU换能器的焦点通过使用函数发生器施加25赫兹振幅调制的信号生成的。与68kPa峰值压力64元件和2.5兆赫成像换能器被共焦地放置在HIFU换能器获取的射频（RF）信道数据的中心。在这个协议中，使用高强度聚焦超声与对体外犬肝7瓦的声功率热消融的实时监控进行说明。在2分钟HIFU治疗被施加在组织上和烧蚀区域是使用发散或平面波成像高达1000帧/秒成像实时。的RF信道的数据的矩阵乘以一个稀疏矩阵图像重建。视重建场是90°的发散わ已经和20毫米的平面波成像和数据进行采样，在80兆赫。重建是在4.5显示帧速率上的图形处理单元（GPU）执行，以图像在实时的。重构RF数据的一维归一化互相关性被用于估计轴向位移在焦点区域。的峰 - 峰位移的在焦深幅度它表示所述组织的硬化由于病灶的形成热消融过程中降低。位移信噪比（SNR D）在重点领域的平面波是比发散波显示出平面波成像的1.4倍似乎产生更好的置换贴图质量HMIFU比发散波成像。

可以用发散和平面波成像获得HMI排量的实时流期间，高强度聚焦超声消融治疗。 图2是在高强度聚焦超声消融视频截屏显示使用平面波成像技术在体外犬肝脏的声辐射力引起的位移实时显示。的位移以4.5赫兹的显示帧速率流在实时计算机屏幕上。正位移示于红色和负位移为蓝色。病变使用HIFU消融。 图3示出对应于图2的消融后在肝脏中获得的病变被成功?...

Watch this Scientific Journal Video about Real-time Monitoring of High Intensity Focused Ultrasound HIFU Ablation of In Vitro Canine Livers Using Harmonic Motion Imaging for Focused Ultrasound HMIFU a

Real-time Monitoring of High Intensity Focused Ultrasound HIFU Ablation of In Vitro Canine Livers Using Harmonic Motion Imaging for Focused Ultrasound HMIFU

This article describes real-time monitoring of HIFU ablation in canine liver with high frame rate ultrasound imaging using diverging and plane wave imaging. Harmonic Motion Imaging for Focused Ultrasound is used to image the decrease of acoustic radiation force induced displacement in the ablated region.

高强度的实时监控聚焦超声（HIFU）消融<em&gt;体外</em&gt;使用谐运动成像的聚焦超声犬肝脏（HMIFU）

Harmonic Motion Imaging for Focused Ultrasound (HMIFU) is a technique that can perform and monitor high-intensity focused ultrasound (HIFU) ablation. An ...

real-time-monitoring-high-intensity-focused-ultrasound-hifu-ablation

Research

JoVE Journal

Bioengineering

Real-time Monitoring of High Intensity Focused Ultrasound (HIFU) Ablation of In Vitro Canine Livers Using Harmonic Motion Imaging for Focused Ultrasound (HMIFU)

9.9K 次观看.  Columbia University. This article describes real-time monitoring of HIFU ablation in canine liver with high frame rate ultrasound imaging using diverging and plane wave imaging. Harmonic Motion Imaging for Focused Ultrasound is used to image the decrease of acoustic radiation force induced displacement in the ablated region.

视频: Real-time Monitoring of High Intensity Focused Ultrasound HIFU Ablation of In Vitro Canine Livers Using Harmonic Motion Imaging for Focused Ultrasound HMIFU

Contrast Ultrasound Targeted Treatment of Gliomas in Mice via Drug-Bearing Nanoparticle Delivery and Microvascular Ablation

We are developing minimally-invasive contrast agent microbubble based therapeutic approaches in which the permeabilization and/or ablation of the microvasculature are controlled by varying ultrasound pulsing parameters.  Specifically, we are testing whether such approaches may be used to treat malignant brain tumors through drug delivery and microvascular ablation.  Preliminary studies have been performed to determine whether targeted drug-bearing nanoparticle delivery can be facilitated by the ultrasound mediated destruction of "composite" delivery agents comprised of 100nm poly(lactide-co-glycolide) (PLAGA) nanoparticles that are adhered to albumin shelled microbubbles. We denote these agents as microbubble-nanoparticle composite agents (MNCAs). When targeted to subcutaneous C6 gliomas with ultrasound, we observed an immediate 4.6-fold increase in nanoparticle delivery in MNCA treated tumors over tumors treated with microbubbles co-administered with nanoparticles and a 8.5 fold increase over non-treated tumors. Furthermore, in many cancer applications, we believe it may be desirable to perform targeted drug delivery in conjunction with ablation of the tumor microcirculation, which will lead to tumor hypoxia and apoptosis. To this end, we have tested the efficacy of non-theramal cavitation-induced microvascular ablation, showing that this approach elicits tumor perfusion reduction, apoptosis, significant growth inhibition, and necrosis. Taken together, these results indicate that our ultrasound-targeted approach has the potential to increase therapeutic efficiency by creating tumor necrosis through microvascular ablation and/or simultaneously enhancing the drug payload in gliomas.

Insonation of microbubbles is a promising strategy for tumor ablation at reduced time-averaged acoustic powers, as well as for the targeted delivery of therapeutics. The purpose of the present study is to develop low duty cycle ultrasound pulsing strategies and nanocarriers to maximize non-thermal microvascular ablation and payload delivery to subcutaneous C6 gliomas.

超声造影有针对性的治疗胶质瘤的小鼠通过药物轴承纳米粒子交付和微血管消融

We are developing minimally-invasive contrast agent microbubble based therapeutic approaches in which the permeabilization and/or ablation of the ...

科研

生物工程

Decellularization and Recellularization of Whole Livers

The liver is a complex organ which requires constant perfusion for delivery of nutrients and oxygen and removal of waste in order to survive1. Efforts to recreate or mimic the liver microstructure with grounds up approach using tissue engineering and microfabrication techniques have not been successful so far due to this design challenge. In addition, synthetic biomaterials used to create scaffolds for liver tissue engineering applications have been limited in inducing tissue regeneration and repair in large part due to the lack of specific cell binding motifs that would induce the proper cell functions2. Decellularized native tissues such blood vessels3and skin4on the other hand have found many applications in tissue engineering, and have provided a practical solution to some of the challenges. The advantage of decellularized native matrix is that it retains, to an extent, the original composition, and the microstructure, hence enhancing cell attachment and reorganization5.
In this work we describe the methods to perform perfusion-decellularization of the liver, such that an intact liver bioscaffold that retains the structure of major blood vessels is obtained. Further, we describe methods to recellularize these bioscaffolds with adult primary hepatocytes, creating a liver graft that is functional in vitro, and has the vessel access necessary for transplantation in vivo.

Perfusion decellularization is a novel technique to produce whole liver scaffolds that retains the organ's extracellular matrix composition and microarchitecture. Herein, the method of preparing whole organ scaffolds using perfusion decellularization and subsequent repopulation with hepatocytes is described. Functional and transplantable liver grafts can be generated using this technique.

整个肝脏的脱细胞和Recellularization

The liver is a complex organ which requires constant perfusion for delivery of nutrients and oxygen and removal of waste in order to survive1. Efforts to ...

Induction of Adhesion-dependent Signals Using Low-intensity Ultrasound

In multicellular organisms, cell behavior is dictated by interactions with the extracellular matrix. Consequences of matrix-engagement range from regulation of cell migration and proliferation, to secretion and even differentiation. The signals underlying each of these complex processes arise from the molecular interactions of extracellular matrix receptors on the surface of the cell. Integrins are the prototypic receptors and provide a mechanical link between extracellular matrix and the cytoskeleton, as well as initiating some of the adhesion-dependent signaling cascades. However, it is becoming increasingly apparent that additional transmembrane receptors function alongside the integrins to regulate both the integrin itself and signals downstream. The most elegant of these examples is the transmembrane proteoglycan, syndecan-4, which cooperates with &alpha;5&beta;1-integrin during adhesion to fibronectin. In vivo models demonstrate the importance of syndecan-4 signaling, as syndecan-4-knockout mice exhibit healing retardation due to inefficient fibroblast migration1,2. In wild-type animals, migration of fibroblasts toward a wound is triggered by the appearance of fibronectin that leaks from damaged capillaries and is deposited by macrophages in injured tissue. Therefore there is great interest in discovering strategies that enhance fibronectin-dependent signaling and could accelerate repair processes.
The integrin-mediated and syndecan-4-mediated components of fibronectin-dependent signaling can be separated by stimulating cells with recombinant fibronectin fragments. Although integrin engagement is essential for cell adhesion, certain fibronectin-dependent signals are regulated by syndecan-4. Syndecan-4 activates the Rac1 protrusive signal3, causes integrin redistribution1, triggers recruitment of cytoskeletal molecules, such as vinculin, to focal adhesions4, and thereby induces directional migration3. We have looked for alternative strategies for activating such signals and found that low-intensity pulsed ultrasound (LIPUS) can mimic the effects of syndecan-4 engagement5. In this protocol we describe the method by which 30 mW/cm2, 1.5 MHz ultrasound, pulsed at 1 kHz (Fig. 1) can be applied to fibroblasts in culture (Fig. 2) to induce Rac1 activation and focal adhesion formation. Ultrasound stimulation is applied for a maximum of 20 minutes, as this combination of parameters has been found to be most efficacious for acceleration of clinical fracture repair6. The method uses recombinant fibronectin fragments to engage &alpha;5&beta;1-integrin, without engagement of syndecan-4, and requires inhibition of protein synthesis by cycloheximide to block deposition of additional matrix by the fibroblasts., The positive effect of ultrasound on repair mechanisms is well documented7,8, and by understanding the molecular effect of ultrasound in culture we should be able to refine the therapeutic technique to improve clinical outcomes.

This protocol describes the stimulation of cultured fibroblasts with low-intensity pulsed ultrasound, which drives focal adhesion formation and Rac1 activation by mimicking engagement of the transmembrane matrix receptor, syndecan-4. This approach allows investigation of a successful clinical technique at the cellular level, thereby providing opportunities for refinement of the therapy.

诱导粘附依赖使用低强度超声波信号

In multicellular organisms, cell behavior is dictated by interactions with the extracellular matrix. Consequences of matrix-engagement range from ...

Wideband Optical Detector of Ultrasound for Medical Imaging Applications

Optical sensors of ultrasound are a promising alternative to piezoelectric techniques, as has been recently demonstrated in the field of optoacoustic imaging. In medical applications, one of the major limitations of optical sensing technology is its susceptibility to environmental conditions, e.g. changes in pressure and temperature, which may saturate the detection. Additionally, the clinical environment often imposes stringent limits on the size and robustness of the sensor. In this work, the combination of pulse interferometry and fiber-based optical sensing is demonstrated for ultrasound detection. Pulse interferometry enables robust performance of the readout system in the presence of rapid variations in the environmental conditions, whereas the use of all-fiber technology leads to a mechanically flexible sensing element compatible with highly demanding medical applications such as intravascular imaging. In order to achieve a short sensor length, a pi-phase-shifted fiber Bragg grating is used, which acts as a resonator trapping light over an effective length of 350 &#181;m. To enable high bandwidth, the sensor is used for sideway detection of ultrasound, which is highly beneficial in circumferential imaging geometries such as intravascular imaging. An optoacoustic imaging setup is used to determine the response of the sensor for acoustic point sources at different positions.

Optical detection of ultrasound is impractical in many imaging scenarios because it often requires stable environmental conditions. We demonstrate an optical technique for ultrasound sensing in volatile environments with miniaturization and sensitivity levels appropriate for optoacoustic imaging in restrictive scenarios, e.g. intravascular applications.

宽带超声医疗成像应用，光学检测仪

Optical sensors of ultrasound are a promising alternative to piezoelectric techniques, as has been recently demonstrated in the field of optoacoustic ...

Universal Hand-held Three-dimensional Optoacoustic Imaging Probe for Deep Tissue Human Angiography and Functional Preclinical Studies in Real Time

The exclusive combination of high optical contrast and excellent spatial resolution makes optoacoustics (photoacoustics) ideal for simultaneously attaining anatomical, functional and molecular contrast in deep optically opaque tissues. While enormous potential has been recently demonstrated in the application of optoacoustics for small animal research, vast efforts have also been undertaken in translating this imaging technology into clinical practice. We present here a newly developed optoacoustic tomography approach capable of delivering high resolution and spectrally enriched volumetric images of tissue morphology and function in real time. A detailed description of the experimental protocol for operating with the imaging system in both hand-held and stationary modes is provided and showcased for different potential scenarios involving functional and molecular studies in murine models and humans. The possibility for real time visualization in three dimensions along with the versatile handheld design of the imaging probe make the newly developed approach unique among the pantheon of imaging modalities used in today&#8217;s preclinical research and clinical practice.

We provide herein a detailed description of the experimental protocol for imaging with a newly developed hand-held optoacoustic (photoacoustic) system for three-dimensional functional and molecular imaging in real time. The demonstrated powerful performance and versatility may define new application areas of the optoacoustic technology in preclinical research and clinical practice.

通用型手持式三维光声成像探测深部组织人力造影和功能的临床前研究中实时

The exclusive combination of high optical contrast and excellent spatial resolution makes optoacoustics (photoacoustics) ideal for simultaneously ...

Eye Irritation Test (EIT) for Hazard Identification of Eye Irritating Chemicals using Reconstructed Human Cornea-like Epithelial (RhCE) Tissue Model

To comply with the Seventh Amendment to the EU Cosmetics Directive and EU REACH legislation, validated non-animal alternative methods for reliable and accurate assessment of ocular toxicity in man are needed. To address this need, we have developed an eye irritation test (EIT) which utilizes a three dimensional reconstructed human cornea-like epithelial (RhCE) tissue model that is based on normal human cells. The EIT is able to separate ocular&#160;irritants and corrosives (GHS Categories 1 and 2 combined) and those that do not require labeling (GHS No Category). The test utilizes two separate protocols, one designed for liquid chemicals and a second, similar protocol for solid test articles. The EIT prediction model uses a single exposure period (30 min for liquids, 6 hr for solids) and a single tissue viability cut-off (60.0% as determined by the MTT assay). Based on the results for 83 chemicals (44 liquids and 39 solids) EIT achieved 95.5/68.2/ and 81.8% sensitivity/specificity and accuracy (SS&#38;A) for liquids, 100.0/68.4/ and 84.6% SS&#38;A for solids, and 97.6/68.3/ and 83.1% for overall SS&#38;A. The EIT will contribute significantly to classifying the ocular irritation potential of a wide range of liquid and solid chemicals without the use of animals to meet regulatory testing requirements. The EpiOcular EIT method was implemented in 2015 into the OECD Test Guidelines as TG 492.

Eye Irritation Test EIT for Hazard Identification of Eye Irritating Chemicals using Reconstructed Human Cornea-like Epithelial RhCE Tissue Model

We have developed an eye irritation test which utilizes a three dimensional reconstructed human cornea-like epithelial (RhCE) tissue model. The test is able to discriminate between ocular irritant and corrosive materials (GHS Categories 1 and 2 combined) and those that do not require labeling (GHS No Category).

眼刺激试验（EIT）使用重构型人角膜上皮样（RHCE）组织模型眼刺激性化学品危险性鉴定

To comply with the Seventh Amendment to the EU Cosmetics Directive and EU REACH legislation, validated non-animal alternative methods for reliable and ...

Real Time Monitoring of Intracellular Bile Acid Dynamics Using a Genetically Encoded FRET-based Bile Acid Sensor

F&#246;rster Resonance Energy Transfer (FRET) has become a powerful tool for monitoring protein folding, interaction and localization in single cells. Biosensors relying on the principle of FRET have enabled real-time visualization of subcellular signaling events in live cells with high temporal and spatial resolution. Here, we describe the application of a genetically encoded Bile Acid Sensor (BAS) that consists of two fluorophores fused to the farnesoid X receptor ligand binding domain (FXR-LBD), thereby forming a bile acid sensor that can be activated by a large number of bile acids species and other (synthetic) FXR ligands. This sensor can be targeted to different cellular compartments including the nucleus (NucleoBAS) and cytosol (CytoBAS) to measure bile acid concentrations locally. It allows rapid and simple quantitation of cellular bile acid influx, efflux and subcellular distribution of endogenous bile acids without the need for labeling with fluorescent tags or radionuclei. Furthermore, the BAS FRET sensors can be useful for monitoring FXR ligand binding. Finally, we show that this FRET biosensor can be combined with imaging of other spectrally distinct fluorophores. This allows for combined analysis of intracellular bile acid dynamics and i) localization and/or abundance of proteins of interest, or ii) intracellular signaling in a single cell.

We provide a detailed protocol to study bile acid dynamics in living cells using a genetically encoded BAS FRET sensor. This Bile Acid Sensor represents a unique tool to study (regulation of) bile acid transport and FXR activation in a wide range of cell types.

细胞内胆汁酸动态实时监控使用遗传编码的FRET为基础的胆汁酸传感器

F&#246;rster Resonance Energy Transfer (FRET) has become a powerful tool for monitoring protein folding, interaction and localization in single cells. ...

Proper Positioning and Restraint of a Rat Hind Limb for Focused High Resolution Imaging of Bone Micro-architecture Using In Vivo Micro-computed Tomography

The use of in vivo micro-computed tomography (&#181;CT) is a powerful tool which involves the non-destructive imaging of internal structures at high resolutions in live animal models. This allows for repeated imaging of the same rodent over time. This feature not only reduces the total number of rodents required in an experimental design and thereby reduces the inter-subject variation that can arise, but also allows researchers to assess longitudinal or life-long responses to an intervention. To acquire high quality images that can be processed and analyzed to more accurately quantify outcomes of bone micro-architecture, users of in vivo &#181;CT scanners must properly anesthetize the rat, and position and restrain the hind limb. To do this, it is imperative that the rat be anesthetized to a level of complete relaxation, and that pedal reflexes are lost. These guidelines may be modified for each individual rat, as the rate of isoflurane metabolism can vary depending on strain and body size. Proper technique for in vivo &#181;CT image acquisition enables accurate and consistent measurement of bone micro-architecture within and across studies.

Proper Positioning and Restraint of a Rat Hind Limb for Focused High Resolution Imaging of Bone Micro-architecture Using In Vivo Micro-computed Tomography

This paper instructs users of in vivo micro-computed tomography (&#181;CT) scanners how to anesthetize, correctly position and restrain the hind limb of a rat for minimal movement during high-resolution imaging of the tibia. The result is high quality images that can be processed to accurately quantify bone micro-architecture.

应用活体显微计算机断层成像技术对骨微结构高分辨成像大鼠后肢的定位与抑制

The use of in vivo micro-computed tomography (&#181;CT) is a powerful tool which involves the non-destructive imaging of internal structures at high ...

Hand-held Clinical Photoacoustic Imaging System for Real-time Non-invasive Small Animal Imaging

Translation of photoacoustic imaging into the clinic is a major challenge. Handheld real-time clinical photoacoustic imaging systems are very rare. Here, we report a combined photoacoustic and clinical ultrasound imaging system by integrating an ultrasound probe with light delivery for small animal imaging. We demonstrate this by showing sentinel lymph node imaging in small animals along with minimally invasive real-time needle guidance. A clinical ultrasound platform with access to raw channel data allows the integration of photoacoustic imaging leading to a handheld real-time clinical photoacoustic imaging system. Methylene blue was used for sentinel lymph node imaging at 675 nm wavelength. Additionally, needle guidance with dual modal ultrasound and photoacoustic imaging was shown using the imaging system. Depth imaging of up to 1.5 cm was demonstrated with a 10 Hz laser at a photoacoustic imaging frame rate of 5 frames per second.

A clinical handheld photoacoustic imaging system will be demonstrated for real-time non-invasive small animal imaging.

手持式实时非侵入性小动物成像的临床光声成像系统

Translation of photoacoustic imaging into the clinic is a major challenge. Handheld real-time clinical photoacoustic imaging systems are very rare. Here, ...

Focused Ion Beam Lithography to Etch Nano-architectures into Microelectrodes

With advances in electronics and fabrication technology, intracortical microelectrodes have undergone substantial improvements enabling the production of sophisticated microelectrodes with greater resolution and expanded capabilities. The progress in fabrication technology has supported the development of biomimetic electrodes, which aim to seamlessly integrate into the brain parenchyma, reduce the neuroinflammatory response observed after electrode insertion and improve the quality and longevity of electrophysiological recordings. Here we describe a protocol to employ a biomimetic approach recently classified as nano-architecture. The use of focused ion beam lithography (FIB) was utilized in this protocol to etch specific nano-architecture features into the surface of non-functional and functional single shank intracortical microelectrodes. Etching nano-architectures into the electrode surface indicated possible improvements of biocompatibility and functionality of the implanted device. One of the benefits of using FIB is the ability to etch on manufactured devices, as opposed to during the fabrication of the device, facilitating boundless possibilities to modify numerous medical devices post-manufacturing. The protocol presented herein can be optimized for various material types, nano-architecture features, and types of devices. Augmenting the surface of implanted medical devices can improve the device performance and integration into the tissue.

We have shown that the etching of nano-architecture into intracortical microelectrode devices may reduce the inflammatory response and has the potential to improve electrophysiological recordings. The methods described herein outline an approach to etch nano-architectures into the surface of non-functional and functional single shank silicon intracortical microelectrodes.

聚焦 Ion 光束平版印刷到蚀刻纳米架构到微电极

With advances in electronics and fabrication technology, intracortical microelectrodes have undergone substantial improvements enabling the production of ...