本研究では、米航空宇宙局（NASA）ネブラスカスペースグラント助成番号0926880の下で国立科学財団によって部分的にサポートされていました。

1。ラテックス容器の準備<ol><li>頑丈なワークベンチに固定されているとげのあるホース接続にラテックス容器の両端を固定します。 </li><li>ビューのフィールドを決定するためにラテックス容器の上に関心領域を測定します。ステント試験の対象となる領域は有刺鉄線ホースコネクタの間を中心とし、ステント留置領域の外側の株を観察するためにステントの両側に約1インチを含める必要があります。 </li><li> 1有刺鉄線ホースコネクタの外側の端からもラテックス容器のほぼ中央にあるコネクタとの間の中心位置までの距離を記録します。カテーテルまでステントの中心から測定することにより、カテーテル上の距離を変換します。その後、マーカーの付いたカテーテルをマークします。 </li><li>とげのあるホースコネクタからラテックス容器を取り外します。 </li><li>白と黒のスプレー塗料の確率パターンと関心のある領域を噴霧またはマークすることによって、ラテックス容器を準備します。永久的なマーカーを用いたランダムドットの関心領域。小さいサンプルと細かい確率パターンが必要になります。 </li></ol> ARAMISシステムの2 in vitroの試験システムとキャリブレーション<ol><li>ステップ1で測定された関心領域よりも若干大きいのキャリブレーションパネルを選択します。 </li><li>興味のあるエリアで有刺鉄線ホースコネクタ間のキャリブレーションパネルを配置し、関心領域がよく点灯していることを確認してください。 </li><li>二台のカメラ、サンプルからの距離や、選択したキャリブレーションパネルに基づいて、カメラの高さとの間の距離を調整します。各キャリブレーションパネルは異なりますのでARAMISのユーザマニュアルは、これらの距離を決定するために相談する必要があります。 </li><li> &quot;新規プロジェクト&quot;、次に &quot;ファイル&quot;を選択してARAMISで新しいプロジェクトを開きます。次の &quot;センサー&quot;タブをクリックし、 &quot;キャリブレーション&quot;を選択し、 &quot;フルキャリブレーション&quot;。 </li><li> ARAMISソフトウェアは、tをキャリブレーションする手順を通してユーザーを歩いていく<html>彼のカメラ。 </li><li>完全に開いてレンズの絞りを使用すると、カメラにセットスクリューを緩めて、レンズを回転させることにより、キャリブレーションパネルでカメラの焦点を合わせる。一度集中し、セットスクリューを締めと絞りを閉じます。 </li><li>キャリブレーションプロセスの最初の画像になります。画像は、コンピュータの画面に焦点を当てされるまで、コンピュータ上のデモに従ってキャリブレーションパネルを変位または回転させます。 2枚目の画像を。キャリブレーション画像の残りのために、このプロセスを繰り返します。 </li><li>一度キャリブレーション画像のすべてが取られ、ARAMIS画像解析ソフトウェアは、キャリブレーションの設定を計算します。キャリブレーション偏差が0.04より大きい場合のキャリブレーションプロセスが繰り返されるべきである。カメラのフォーカスやカメラ間の距離に行われたすべての調整は、校正プロセスvoidをレンダリングします。 </li><li>キャリブレーションパネルを取り外し、有刺鉄線ホースコネクタに戻って塗装ラテックス容器を置きます。 </li></ol>過剰なバックグラウンドノイズを回避するためにタイトル &quot;&gt; 3。プリテスト<ol><li>テストのために望まれている1秒あたりのフレーム数を決定します。毎秒増加したフレームは、より均一なひずみの結果を生成します。 </li><li>毎秒1未満のフレームにシャッタースピードを調整しない赤は、画像に表示されないようにします。 </li><li> 5枚を取る。 </li><li>画像系列上のポイントを開始し、テストを計算に追加します。 </li><li> &quot;CTRL&quot;を押しながら、バックグラウンドノイズを観察する試料の中心をクリックします。プリテストノイズがmicrostrain 75を超えている場合は、キャリブレーションプロセスをやり直す必要があります。 </li></ol> 4。ステント配置<ol><li>テスト中に取るように所望の画像の量を選択します。 200枚は、ステントの拡張のために十分であろう。 </li><li>徐々にラテックス容器内にカテーテルを挿入し、それが中央の位置に達するまで、ステント挿入を案内するカテーテル上のマーカーインジケータを使用します。 </li><li> ARAMISで画像を撮影開始します。 </li><li>バルーン拡張型ステントでは、徐々にバルーンが完全に展開されるまで、ステント拡張するバルーンの圧力を増加し、次に徐々にゼロにバルーンの圧力を減少させ、バルーンが収縮し、カテーテルと一緒に撤回されています。 </li><li>ステントが完全に展開されるまで自己拡張型ステントでは、徐々にシースを除去してから、徐々にカテーテルを撤回。 </li></ol> 5。画像解析<ol><li> 容器上の特定の点のひずみ履歴 <ol><li>興味のある領域に &quot;Ctrl&quot;キーを押しながらクリックして、ステージのポイントを作成します。 </li><li> X、Y、XY、主要なひずみ、マイナー株またはミーゼスひずみで必要に応じて、すなわち株である株の種類を選択します。 </li><li>右下隅にあるプロットは、テストの期間に​​わたって選択された時点で歪みが表示されます。 </li></ol></li><li> 船舶の特定のパスに沿って空間的な歪み <ol><li> CR&quot;セクション&quot;タブをクリックして多段ポイントラインをeateし、 &quot;セクションを作成&quot;。 YのX軸に画像の平行のラインを選択してはゼロに等しくなります。これはラインのステージポイントの数を作成します。 </li><li>多段の行が作成された後に下の隅にあるプロットは、1プロット上の一連の行が表示されます。各行には、セクションの長さに沿って時間内の1つのインスタンスのひずみを表しています。 </li></ol></li><li> 容器の膨張率と半径を分析するための最適なシリンダーを作成する <ol><li>上部のツール·バーにして、 &quot;最適なシリンダー&quot;を &quot;プリミティブ&quot;を選択してください。 </li><li>右側のツールバーにある &quot;表面を介して選択し、&quot;ツールを使用して、イメージの小さなセクションを選択します。 </li><li> ARAMISソフトウェアは、三次元ベストフィットシリンダーを生成します。 </li><li>画像はその後ラテックス容器の直径が変動する様子を観察することを通じて、循環することができます。 </li></ol></li><li> 間の距離を評価する二つの点<ol><li> &quot;分析&quot;タブの下に &quot;距離をポイントツーポイント&quot;をクリックします。 </li><li>二つの点を選択することにより、分析のために望まれている画像上の長さを選択します。 </li><li>画像は、その後時間をかけて2点間の距離の変化を観察することを通じて、循環することができます。 </li></ol></li></ol> 6。代表的な結果ステントストラットが血管壁を外側に展開し、株は一般的にステント位置の周りに高くなります。 図1つの特定の時点ではバルーン拡張型ステントと同様に、主要なひずみ履歴の反動プロセスの間にひずみマッピングの例です。 図1の黒い点は、導管にこれらの基準点の変位をキャプチャし、追跡するために高速カメラで使用された基準点である。基準点の記録の動きに基づいて、ソフトウェアは次に導管の株または計算するために使用されます。ニューヨークの他のターゲットオブジェクト。また、最大主ひずみと呼ばれる主要な株は、次のように計算されます。 <img alt="式（1）" src="/files/ftp_upload/3945/3945eq1.jpg" />それが移植されたステントは、血管の表面に不均一なひずみ分布につながったことは明らかである。これは、両端に制約のあるラテックス管とステントの網目構造からの反動の負荷によって説明することができます。この歪場は、 図1の一番下の画像に赤い十字マーカーによって識別されたステントリコイル、初期の段階に対応しています。特定のポイント10の主要なひずみ履歴曲線は、ステントの区別の段階を示した。バルーン拡張はバルーンのデフレーション後約10秒から12秒とステント反動から12と14秒の間で発生する発生します。 <img alt="図1" src="/files/ftp_upload/3945/3945fig1.jpg" /> 図1。 </strong&gt;実験装置（上）、ステント管面上の不均一ひずみ分布（中央）、ポイント10（下）における主要なひずみ履歴。

<ol>
	<li>Fischman, D. L., Leon, M. B., Baim, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+randomized+comparison+of+coronary-stent+placement+and+balloon+angioplasty+in+the+treatment+of+coronary+artery+disease.+Stent+Restenosis+Study+Investigators.">A randomized comparison of coronary-stent placement and balloon angioplasty in the treatment of coronary artery disease. Stent Restenosis Study Investigators.</a> N. Engl. J. Med. 331, 496-501 (1994).</li><li>Abul Hasan Muhammad Bashar, T. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+Properties+of+Various+Z-Stent+Designs:+An+Endovascular+Stent-Grafting+Perspective.">Mechanical Properties of Various Z-Stent Designs: An Endovascular Stent-Grafting Perspective.</a> Artificial Organs. 27, 714-721 (2003).</li><li>Nuutinen, J. u. h. a. -. P. e. k. k. a. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+properties+and+in+vitro+degradation+of+bioabsorbable+self-expanding+braided+stents.">Mechanical properties and in vitro degradation of bioabsorbable self-expanding braided stents.</a> Journal of Biomaterials Science -- Polymer Edition. , 255-266 (2003).</li><li>C. Schulz, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coronary+stent+symmetry+and+vascular+injury+determine+experimental+restenosis.">Coronary stent symmetry and vascular injury determine experimental restenosis.</a> Heart. 83, 462-467 (2000).</li><li>Jiménez, J. M., Davies, P. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hemodynamically+Driven+Stent+Strut+Design.">Hemodynamically Driven Stent Strut Design.</a> Annals of Biomedical Engineering. 1483, (2009).</li><li>Johnston, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Mechanical+Properties+of+Endovascular+Stents:+An+In+Vitro+Assessment.">The Mechanical Properties of Endovascular Stents: An In Vitro Assessment.</a> Cardiovascular Engineering: An International Journal. 10, 128-135 (2010).</li><li>Mejia, J. u. a. n. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+the+effect+of+stent+strut+profile+on+shear+stress+distribution+using+statistical+moments.">Evaluation of the effect of stent strut profile on shear stress distribution using statistical moments.</a> Biomedical Engineering Online. , 1-10 (2009).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> ARAMIS User Manual. , (2009).</li><li>Chesler, N. C., Thompson-Figueroa, J., Millburne, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurements+of+Mouse+Pulmonary+Biomechanics.">Measurements of Mouse Pulmonary Biomechanics.</a> Journal of Biomechanical Engineering. 126, 309-314 (2004).</li><li>de Korte, C. L., Sierevogel, M. J., Mastik, F., Strijder, C., Schaar, J. A., Velema, E., Pasterkamp, G., Serruys, P. W., van der Steen, A. F. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+Atherosclerotic+Plaque+Components+With+Intravascular+Ultrasound+Elastography+In+Vivo+A+Yucatan+Pig+Study.">Identification of Atherosclerotic Plaque Components With Intravascular Ultrasound Elastography In Vivo A Yucatan Pig Study.</a> Circulation. 105, 1627-1630 (2002).</li></ol>

利害の衝突が宣言されません。

ステレオ光学面のひずみ測定システムは、試料に接触することなく両方のインとアウトの平面運動のために変形し、表面上の局所ひずみを測定するために使用されています。このシステムは、表面の株を解決するための高精度で、各点の動きの正確な測定を構築するために表面に置いてランダム対照的なパターンの写真を撮るために2つの高速光学カメラを使用しています。 <p class="jove_cont...

<table border="1"><tbody><tr><td> 使用する機器 </td><td> 会社 </td><td> カタログ番号 </td><td> コメント </td></tr><tr><td> ARAMISカメラシステム</td><td> GOM：光測定技術</td><td></td><td></td></tr><tr><td> PALMAZジェネシス肝胆管ステント</td><td>コー​​ディス</td><td> PG5910B </td><td>バルーン拡張ステント</td></tr><tr><td> Z-MEDバルーン拡張カテーテル</td><td> B. Braunはメディカル株式会社</td><td> PDZ336 </td><td>バルーン拡張カテーテル</td></tr></tbody></table>

monitoring the wall mechanics during stent deployment in a vessel

臨床試験は、様々なステントのデザイン1の別の再狭窄率を報告している。それは動脈壁にステント誘起歪の濃度が再狭窄2-7を開始する組織損傷につながることが推測されています。この仮説は、ステント移植後動脈の非均一ひずみ分布の優れた数量化を含む更な​​る調査が必要である。ステント動脈の非接触面のひずみ測定法は、この作品で提示されます。 ARAMISステレオ光学面のひずみ計測システムは、各基準点の動きをキャプチャするために2つの光高速カメラを使用しており、変形表面8,9を介して三次元の株を解決します。メッシュステントは、その外表面に噴霧または描かれたランダム対照的なパターンでラテックス容器にデプロイされると、表面のひずみは変形のあらゆる瞬間に記録されます。計算されたひずみ分布は、その後、LOを理解するために使用することができますCALの病変の応答は、計算モデルを検証し、in vivoでの研究の更なるための仮説を定式化する。

Watch this Scientific Journal Video about Monitoring the Wall Mechanics During Stent Deployment in a Vessel at JoVE.com

Monitoring the Wall Mechanics During Stent Deployment in a Vessel

ステントによって誘発される動脈のひずみ分布は、光学面のひずみ計測システムを用いて特徴付けられる。この可視化技術は、ホスト容器にステント移植の影響への洞察を得るために使用されています。

容器内ステントの展開中の壁の力学を監視する

Clinical trials have reported different restenosis rates for various stent designs1. It is speculated that stent-induced strain concentrations on the ...

monitoring-the-wall-mechanics-during-stent-deployment-in-a-vessel

Research

JoVE Journal

Bioengineering

9.2K ビュー.  University of Nebraska-Lincoln. ステントによって誘発される動脈のひずみ分布は、光学面のひずみ計測システムを用いて特徴付けられる。この可視化技術は、ホスト容器にステント移植の影響への洞察を得るために使用されています。

ビデオ: Monitoring the Wall Mechanics During Stent Deployment in a Vessel

Magnetic Resonance Elastography Methodology for the Evaluation of Tissue Engineered Construct Growth

Traditional mechanical testing often results in the destruction of the sample, and in the case of long term tissue engineered construct studies, the use of destructive assessment is not acceptable. A proposed alternative is the use of an imaging process called magnetic resonance elastography. Elastography is a nondestructive method for determining the engineered outcome by measuring local mechanical property values (i.e., complex shear modulus), which are essential markers for identifying the structure and functionality of a tissue. As a noninvasive means for evaluation, the monitoring of engineered constructs with imaging modalities such as magnetic resonance imaging (MRI) has seen increasing interest in the past decade1. For example, the magnetic resonance (MR) techniques of diffusion and relaxometry have been able to characterize the changes in chemical and physical properties during engineered tissue development2. The method proposed in the following protocol uses microscopic magnetic resonance elastography (&mu;MRE) as a noninvasive MR based technique for measuring the mechanical properties of small soft tissues3. MRE is achieved by coupling a sonic mechanical actuator with the tissue of interest and recording the shear wave propagation with an MR scanner4. Recently, &mu;MRE has been applied in tissue engineering to acquire essential growth information that is traditionally measured using destructive mechanical macroscopic techniques5. In the following procedure, elastography is achieved through the imaging of engineered constructs with a modified Hahn spin-echo sequence coupled with a mechanical actuator. As shown in Figure 1, the modified sequence synchronizes image acquisition with the transmission of external shear waves; subsequently, the motion is sensitized through the use of oscillating bipolar pairs. Following collection of images with positive and negative motion sensitization, complex division of the data produce a shear wave image. Then, the image is assessed using an inversion algorithm to generate a shear stiffness map6. The resulting measurements at each voxel have been shown to strongly correlate (R2&gt;0.9914) with data collected using dynamic mechanical analysis7. In this study, elastography is integrated into the tissue development process for monitoring human mesenchymal stem cell (hMSC) differentiation into adipogenic and osteogenic constructs as shown in Figure 2.

The procedure demonstrates the methodology of magnetic resonance elastography for monitoring the engineered outcome of adipose and osteogenic tissue engineered constructs through noninvasive local assessment of the mechanical properties using microscopic magnetic resonance elastography (&mu;MRE).

ティッシュエンジニアーコンストラクトの成長評価のための磁気共鳴エラストグラフィの方法論

Traditional mechanical testing often results in the destruction of the sample, and in the case of long term tissue engineered construct studies, the use ...

生物工学

Mass Cytometry: Protocol for Daily Tuning and Running Cell Samples on a CyTOF Mass Cytometer

In recent years, the rapid analysis of single cells has commonly been performed using flow cytometry and fluorescently-labeled antibodies. However, the issue of spectral overlap of fluorophore emissions has limited the number of simultaneous probes. In contrast, the new CyTOF mass cytometer by DVS Sciences couples a liquid single-cell introduction system to an ICP-MS.1 Rather than fluorophores, chelating polymers containing highly-enriched metal isotopes are coupled to antibodies or other specific probes.2-5 Because of the metal purity and mass resolution of the mass cytometer, there is no "spectral overlap" from neighboring isotopes, and therefore no need for compensation matrices. Additionally, due to the use of lanthanide metals, there is no biological background and therefore no equivalent of autofluorescence. With a mass window spanning atomic mass 103-203, theoretically up to 100 labels could be distinguished simultaneously. Currently, more than 35 channels are available using the chelating reagents available from DVS Sciences, allowing unprecedented dissection of the immunological profile of samples.6-7
Disadvantages to mass cytometry include the strict requirement for a separate metal isotope per probe (no equivalent of forward or side scatter), and the fact that it is a destructive technique (no possibility of sorting recovery). The current configuration of the mass cytometer also has a cell transmission rate of only ~25%, thus requiring a higher input number of cells.
Optimal daily performance of the mass cytometer requires several steps. The basic goal of the optimization is to maximize the measured signal intensity of the desired metal isotopes (M) while minimizing the formation of oxides (M+16) that will decrease the M signal intensity and interfere with any desired signal at M+16. The first step is to warm up the machine so a hot, stable ICP plasma has been established. Second, the settings for current and make-up gas flow rate must be optimized on a daily basis. During sample collection, the maximum cell event rate is limited by detector efficiency and processing speed to 1000 cells/sec. However, depending on the sample quality, a slower cell event rate (300-500 cells/sec) is usually desirable to allow better resolution between cells events and thus maximize intact singlets over doublets and debris. Finally, adequate cleaning of the machine at the end of the day helps minimize background signal due to free metal.

The steps necessary for daily tuning and optimization of the performance of a CyTOF mass cytometer are described. Comments on optimal sample preparation and flow rate are discussed

ミササイトメトリー：CyTOFマスメーターで毎日のチューニングと実行した細胞サンプルのためのプロトコル

In recent years, the rapid analysis of single cells has commonly been performed using flow cytometry and fluorescently-labeled antibodies. However, the ...

A Versatile Automated Platform for Micro-scale Cell Stimulation Experiments

Study of cells in culture (in vitro analysis) has provided important insight into complex biological systems. Conventional methods and equipment for in vitro analysis are well suited to study of large numbers of cells (&ge;105) in milliliter-scale volumes (&ge;0.1 ml). However, there are many instances in which it is necessary or desirable to scale down culture size to reduce consumption of the cells of interest and/or reagents required for their culture, stimulation, or processing. Unfortunately, conventional approaches do not support precise and reproducible manipulation of micro-scale cultures, and the microfluidics-based automated systems currently available are too complex and specialized for routine use by most laboratories. To address this problem, we have developed a simple and versatile technology platform for automated culture, stimulation, and recovery of small populations of cells (100 - 2,000 cells) in micro-scale volumes (1 - 20 &mu;l). The platform consists of a set of fibronectin-coated microcapillaries ("cell perfusion chambers"), within which micro-scale cultures are established, maintained, and stimulated; a digital microfluidics (DMF) device outfitted with "transfer" microcapillaries ("central hub"), which routes cells and reagents to and from the perfusion chambers; a high-precision syringe pump, which powers transport of materials between the perfusion chambers and the central hub; and an electronic interface that provides control over transport of materials, which is coordinated and automated via pre-determined scripts. As an example, we used the platform to facilitate study of transcriptional responses elicited in immune cells upon challenge with bacteria. Use of the platform enabled us to reduce consumption of cells and reagents, minimize experiment-to-experiment variability, and re-direct hands-on labor. Given the advantages that it confers, as well as its accessibility and versatility, our platform should find use in a wide variety of laboratories and applications, and prove especially useful in facilitating analysis of cells and stimuli that are available in only limited quantities.

We have developed an automated cell culture and interrogation platform for micro-scale cell stimulation experiments. The platform offers simple, versatile, and precise control in cultivating and stimulating small populations of cells, and recovering lysates for molecular analyses. The platform is well suited to studies that use precious cells and/or reagents.

マイクロスケール細胞刺激のための実験のための多目的自動化プラットフォーム

Study of cells in culture (in vitro analysis) has provided important insight into complex biological systems. Conventional methods and equipment for in ...

Experimental Investigation of Secondary Flow Structures Downstream of a Model Type IV Stent Failure in a 180&#176; Curved Artery Test Section

The arterial network in the human vasculature comprises of ubiquitously present blood vessels with complex geometries (branches, curvatures and tortuosity). Secondary flow structures are vortical flow patterns that occur in curved arteries due to the combined action of centrifugal forces, adverse pressure gradients and inflow characteristics. Such flow morphologies are greatly affected by pulsatility and multiple harmonics of physiological inflow conditions and vary greatly in size-strength-shape characteristics compared to non-physiological (steady and oscillatory) flows 1 - 7.
Secondary flow structures may ultimately influence the wall shear stress and exposure time of blood-borne particles toward progression of atherosclerosis, restenosis, sensitization of platelets and thrombosis 4 - 6, 8 - 13. Therefore, the ability to detect and characterize these structures under laboratory-controlled conditions is precursor to further clinical investigations.
A common surgical treatment to atherosclerosis is stent implantation, to open up stenosed arteries for unobstructed blood flow. But the concomitant flow perturbations due to stent installations result in multi-scale secondary flow morphologies 4 - 6. Progressively higher order complexities such as asymmetry and loss in coherence can be induced by ensuing stent failures vis-&#224;-vis those under unperturbed flows 5. These stent failures have been classified as &#34;Types I-to-IV&#34; based on failure considerations and clinical severity 14.
This study presents a protocol for the experimental investigation of the complex secondary flow structures due to complete transverse stent fracture and linear displacement of fractured parts (&#34;Type IV&#34;) in a curved artery model. The experimental method involves the implementation of particle image velocimetry (2C-2D PIV) techniques with an archetypal carotid artery inflow waveform, a refractive index matched blood-analog working fluid for phase-averaged measurements 15 - 18. Quantitative identification of secondary flow structures was achieved using concepts of flow physics, critical point theory and a novel wavelet transform algorithm applied to experimental PIV data 5, 6, 19 - 26.

Experimental Investigation of Secondary Flow Structures Downstream of a Model Type IV Stent Failure in a 180&amp;#176; Curved Artery Test Section

Stent implants in stenosed arterial curvatures are prone to "Type IV" failures involving the complete transverse fracture of stents and linear displacement of the fractured parts. We present a protocol for detection of secondary flow (vortical) structures in a curved artery model, downstream of clinically relevant "Type IV" stent failures.

180°湾曲動脈テストセクションにおけるモデルIV型ステントの失敗の下流に二次流れ構造に関する実験的研究

The arterial network in the human vasculature comprises of ubiquitously present blood vessels with complex geometries (branches, curvatures and ...

Adapting the Electrospinning Process to Provide Three Unique Environments for a Tri-layered In Vitro Model of the Airway Wall

Electrospinning is a highly adaptable method producing porous 3D fibrous scaffolds that can be exploited in in vitro cell culture. Alterations to intrinsic parameters within the process allow a high degree of control over scaffold characteristics including fiber diameter, alignment and porosity. By developing scaffolds with similar dimensions and topographies to organ- or tissue-specific extracellular matrices (ECM), micro-environments representative to those that cells are exposed to in situ can be created. 
The airway bronchiole wall, comprised of three main micro-environments, was selected as a model tissue. Using decellularized airway ECM as a guide, we electrospun the non-degradable polymer, polyethylene terephthalate (PET), by three different protocols to produce three individual electrospun scaffolds optimized for epithelial, fibroblast or smooth muscle cell-culture. Using a commercially available bioreactor system, we stably co-cultured the three cell-types to provide an in vitro model of the airway wall over an extended time period.
This model highlights the potential for such methods being employed in in vitro diagnostic studies investigating important inter-cellular cross-talk mechanisms or assessing novel pharmaceutical targets, by providing a relevant platform to allow the culture of fully differentiated adult cells within 3D, tissue-specific environments.

Adapting the Electrospinning Process to Provide Three Unique Environments for a Tri-layered In Vitro Model of the Airway Wall

Advancements in biomaterial technologies enable the development of three-dimensional multi-cell-type constructs. We have developed electrospinning protocols to produce three individual scaffolds to culture the main structural cells of the airway to provide a 3D in vitro model of the airway bronchiole wall.

三層のための3つのユニークな環境を提供するために、エレクトロスピニング法を適応させます<em&gt;インビトロ</em&gt;気道壁のモデル

Electrospinning is a highly adaptable method producing porous 3D fibrous scaffolds that can be exploited in in vitro cell culture. Alterations to ...

Ferromagnetic Bare Metal Stent for Endothelial Cell Capture and Retention

Rapid endothelialization of cardiovascular stents is needed to reduce stent thrombosis and to avoid anti-platelet therapy which can reduce bleeding risk. The feasibility of using magnetic forces to capture and retain endothelial outgrowth cells (EOC) labeled with super paramagnetic iron oxide nanoparticles (SPION) has been shown previously. But this technique requires the development of a mechanically functional stent from a magnetic and biocompatible material followed by in-vitro and in-vivo testing to prove rapid endothelialization. We developed a weakly ferromagnetic stent from 2205 duplex stainless steel using computer aided design (CAD) and its design was further refined using finite element analysis (FEA). The final design of the stent exhibited a principal strain below the fracture limit of the material during mechanical crimping and expansion. One hundred stents were manufactured and a subset of them was used for mechanical testing, retained magnetic field measurements, in-vitro cell capture studies, and in-vivo implantation studies. Ten stents were tested for deployment to verify if they sustained crimping and expansion cycle without failure. Another 10 stents were magnetized using a strong neodymium magnet and their retained magnetic field was measured. The stents showed that the retained magnetism was sufficient to capture SPION-labeled EOC in our in-vitro studies. SPION-labeled EOC capture and retention was verified in large animal models by implanting 1 magnetized stent and 1 non-magnetized control stent in each of 4 pigs. The stented arteries were explanted after 7 days and analyzed histologically. The weakly magnetic stents developed in this study were capable of attracting and retaining SPION-labeled endothelial cells which can promote rapid healing.

Our goals were to design, manufacture and test ferromagnetic stents for endothelial cell capture. Ten stents were tested for fracture and 10 more stents were tested for retained magnetism. Finally, 10 stents were tested in-vitro and 8 more stents were implanted in 4 pigs to show cell capture and retention.

内皮細胞捕捉および保持のための強磁性ベアメタルステント

Rapid endothelialization of cardiovascular stents is needed to reduce stent thrombosis and to avoid anti-platelet therapy which can reduce bleeding risk. ...

Mammalian Cell Encapsulation in Alginate Beads Using a Simple Stirred Vessel

Cell encapsulation in alginate beads has been used for immobilized cell culture in vitro as well as for immunoisolation in vivo. Pancreatic islet encapsulation has been studied extensively as a means to increase islet survival in allogeneic or xenogeneic transplants. Alginate encapsulation is commonly achieved by nozzle extrusion and external gelation. Using this method, cell-containing alginate droplets formed at the tip of nozzles fall into a solution containing divalent cations that cause ionotropic alginate gelation as they diffuse into the droplets. The requirement for droplet formation at the nozzle tip limits the volumetric throughput and alginate concentration that can be achieved. This video describes a scalable emulsification method to encapsulate mammalian cells in 0.5% to 10% alginate with 70% to 90% cell survival. By this alternative method, alginate droplets containing cells and calcium carbonate are emulsified in mineral oil, followed by a decrease in pH leading to internal calcium release and ionotropic alginate gelation. The current method allows the production of alginate beads within 20 min of emulsification. The equipment required for the encapsulation step consists in simple stirred vessels available to most laboratories.

This video and manuscript describe an emulsion-based method to encapsulate mammalian cells in 0.5% to 10% alginate beads which can be produced in large batches using a simple stirred vessel. The encapsulated cells can be cultured in vitro or transplanted for cellular therapy applications.

シンプルな攪拌槽を用いたアルギン酸ビーズにおける哺乳類細胞のカプセル化

Cell encapsulation in alginate beads has been used for immobilized cell culture in vitro as well as for immunoisolation in vivo. Pancreatic islet ...

Simulating the Mechanics of Lens Accommodation via a Manual Lens Stretcher

The goal of this protocol is to mimic the biomechanics of physiological accommodation in a cost-efficient, practical manner. Accommodation is achieved through the contraction of the ciliary body and relaxation of zonule fibers, which results in the thickening of the lens necessary for near vision. Here, we present a novel, simple method in which accommodation is replicated by tensing the zonules connected to the lens capsule via a manual lens stretcher (MLS). This method monitors the radial stretching achieved by a lens when subjected to a consistent force and allows for a comparison of accommodating lenses, which can be stretched, to non-accommodating lenses, which cannot be stretched. Importantly, the stretcher couples to the zonules directly, and not to the sclera of the eye, thus only requiring the lens, zonules, and ciliary body rather than the entire globe sample. This difference can significantly decrease the cost of acquiring donor cadaver lenses by about 62% compared to acquiring an entire globe.

We present an efficient method of studying lens accommodation by using a manual lens stretcher. The protocol mimics physiological accommodation by pulling the zonules connected around the lens capsule, thereby, stretching the lens.

マニュアル レンズ担架による焦点調節機構のシミュレーション

The goal of this protocol is to mimic the biomechanics of physiological accommodation in a cost-efficient, practical manner. Accommodation is achieved ...

Nondestructive Monitoring of Degradable Scaffold-Based Tissue-Engineered Blood Vessel Development Using Optical Coherence Tomography

Engineered vascular grafts with structural and mechanical properties similar to natural blood vessels are expected to meet the growing demand for arterial bypass. Characterization of the growth dynamics and remodeling process of degradable polymer scaffold-based tissue-engineered blood vessels (TEBVs) with pulsatile stimulation is crucial for vascular tissue engineering. Optical imaging techniques stand out as powerful tools for monitoring vascularization of engineered tissue enabling high-resolution imaging in real-time culture. This paper demonstrates a nondestructive and fast real-time imaging strategy to monitor the growth and remodeling of TEBVs in long-term culture by using optical coherence tomography (OCT). Geometric morphology is evaluated, including vascular remodeling process, wall thickness, and comparison of TEBV thickness in different culture time points and presence of pulsatile stimulation. Finally, OCT provides practical possibilities for real-time observation of the degradation of polymer in the reconstructing tissues under pulsatile stimulation or not and in each vessel segment, by compared with the assessment of polymer degradation using scanning electron microscopic(SEM) and polarized microscope.

A step by step protocol for nondestructive and long-period monitoring the process of vascular remodeling and scaffold degradation in real-time culture of biodegradable polymeric scaffold-based tissue-engineered blood vessels with pulsatile stimulation using optical coherence tomography is described here.

光干渉断層計を用いた分解足場ベース組織設計血容器開発の非破壊モニタリング

Engineered vascular grafts with structural and mechanical properties similar to natural blood vessels are expected to meet the growing demand for arterial ...

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.

組織レベルの力学を制御するための準拠基板上のヒト胚性幹細胞コロニーの幾何学的パターン化

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