この研究は、中国国立自然科学財団(81770271;Y、遼)、中国国立自然科学財団の共同資金(U1908205;Y,Liao)、広州科学技術の自治体計画プロジェクト(201804020083;Liao博士)からの助成金によって支えられました。

すべての手順は、米国国立衛生研究所(NIH出版第85-23号、1996年に改訂)が発行した 実験動物のケアと使用 のガイドラインに従って行われました。C57BL/6J雄マウス(8-10週、20〜25g)は、南医科大学動物センターによって提供された。
1. 術前準備
<ol><li>針ホルダーで25G針の先端をつまみ、ホルダーのような硬い物体で鈍らせる。</li>
	<li>5~0 の吸収性縫合糸を針に通し、それをホルダー13で 90° にカーブさせます。 注:異なる研究目的に従って、研究者は異なる吸収時間で吸収可能なラインを選択することができます。このプロトコルでは、大動脈弓を収縮させるために2週間の吸収可能な縫合糸を使用しました。</li>
	<li>別の25G針を120°までカーブさせ、ライゲーションステップでスペーサーとして使用するホルダーで先端を滑らかにします。 注:体重(BW)>25gを持つマウスのスペーサーとして25G針が使用されました。19-24 g BW のマウスには 26 G 針を使用してください。</li>
	<li>75%アルコールで手術部位を消毒します。</li>
	<li>加熱パッドの温度を37°Cに調整します。</li>
	<li>滅菌された手術器具(1つの眼科用ハサミ、1つのマイクロハサミ、2つのマイクロ外科肘ピンセット、1針のホルダーおよび1つのマイクロ針のホールダーを含む)</li>
</ol>2. 麻酔とシェービングの誘導
<ol><li>生理食塩水(0.9%NaCl)で希釈したキシラジン(5mg/kg)とケタミン(100mg/kg)の混合物の腹腔内注射によりマウスを麻酔します。陰性ペダル離脱反射で完全麻酔を確認します。</li>
	<li>縫合糸で切歯を固定し、粘着テープで手足を固定することにより、マウスを上手に置いてください。</li>
	<li>脱毛クリームを適用して、首とシフォイドの毛髪を取り除きます。ヨウ素で地域を消毒し、その後75%のアルコールを消毒します。</li>
</ol>3. 手術
<ol><li>メスで上胸部ノッチと胸部の間の正中位置に10mm以上の切開を行います。次に、皮膚と表面性筋膜を分離する。</li>
	<li>胸骨の角度からリブを数えることによって、最初の肋間空間を識別します。最初の肋間空間で切開を行い、胸骨にできるだけ近い。このスペースを開くために肘のピンセットでそれをぶっきらぼうに貫通してください。</li>
	<li>横大動脈弓が見えるまで、パレンチマと胸腺を穏やかに分離します。 注意:気胸を避けるために頭頂胸膜を損傷しないでください。</li>
	<li>大動脈弓の下に5-0吸収性縫合糸を、腕頭筋動脈と左共通頸動脈の間に、ラッチ針14で渡す。手術場には、腕頭筋動脈、左共通頸動脈、左鎖骨下動脈が見えるようにしてください。</li>
	<li>ステップ1.3で準備したスペーサーを横断大オルタに置き、ステップ3.4で縫合糸でスペーサーにダブルノットを実行します。 注:スペーサーの先端は、それを取り外している間に横の大オルタを傷つけることを避けるために鈍くなければなりません。</li>
	<li>スペーサーを素早くそっと取り出し、縫合糸の端を切ります。</li>
	<li>5-0 ナイロン縫合糸を使用して、最初の肋間空間とスキンを閉じます。75%アルコールで再び皮膚を消毒する。</li>
	<li>回復を促進するために加熱パッドの上にマウスを置きます。手術後最初の3日間、ブプレノルフィン(0.1mg/kg、q12h)腹腔内注射を行う。</li>
	<li>意識回復時に、12時間の明暗サイクル室でマウスをケージに戻します。</li>
	<li>上記の手順と同一の、収縮なしの恥の手術を行う(ステップ3.5)。</li>
	<li>上記のすべてのステップと同じシルク縫合糸群の手術を行いますが、ステップ1.2では5-0シルク縫合糸を使用します。</li>
</ol>4. 結紮と測定の成功の心エコー評価
<ol><li>手術後の日(D)7に対して心エコー評価を行う。</li>
	<li>誘導のための吸入を通して3%のイオブルラン、および0.5-1 L/min酸素流量で麻酔の深さを維持するために1.5%でマウスを麻酔します。</li>
	<li>マウスをプラットフォーム上の上の位置に置き、37°Cに維持し、その手足を電極にテープで貼ります。</li>
	<li>脱毛クリームで胸の毛を取り除き、マウスの胸部に超音波カップリング剤を塗布します。</li>
	<li>30MHzプローブで横大動脈収縮を評価します。<ol>
<li>プラットフォームを左端に傾けます。プローブを垂直位置に保ち、胸部の右寄尾翼線に沿って下げます。次に、大動脈のアーチがはっきりと見えるまで、BモードでX軸とY軸を操作します。</li>
		<li>Bモードで狭窄を見つけて大動脈アーチビュー11を得る。カラードップラーモードとパルス波を使用してピーク流速を測定し、TACグループとして3,000mm/s以上の速度を持つマウスを選択します(値は予備実験に基づいています)。</li>
		<li>ベルヌーイの方程式11の修正版に従って圧力勾配を計算する: 圧力勾配 = 4 x Vmax2. 注: 横方向の大動脈収縮モデルの理想的な圧力勾配は 40 ~ 80 mmHg11から範囲です。</li>
		<li>Cine ストアとフレーム ストアを使用して、データと画像を保存します。</li>
	</ol>
</li>
	<li>30 MHz プローブで左心室(LV)の寸法と収縮性を評価します。<ol>
<li>プラットフォームを水平位置にリセットします。左寄縁線に対して、プローブを反時計回りに30°に保ちます。</li>
		<li>Bモードを使用し、XとYを操作して、心臓の明確で全長の軸図を得ます。</li>
		<li>Mモードを押して、インジケータラインを表示します。後でLVチャンバー寸法、分数短縮、LV壁厚を測定するために、Cine Storeとフレームストアで画像を取得します。</li>
	</ol>
</li>
	<li>一度行われた, イソファラン吸入を停止し、マウスが麻酔から回復することができます.その後、12時間の明暗サイクルルームでケージに動物を戻します。</li>
	<li>手術後のD14とD28では、上記の手順を繰り返して心臓パラメータを測定し、組織学的研究のために心臓を収穫します。</li>
</ol>

<ol>
	<li>Murry, C. E., Jennings, R. B., Reimer, 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=Preconditioning+with+ischemia:+a+delay+of+lethal+cell+injury+in+ischemic+myocardium.">Preconditioning with ischemia: a delay of lethal cell injury in ischemic myocardium.</a> Circulation. 74 (5), 1124-1136 (1986).</li><li>Ban, K., 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=Phosphatidylinositol+3-kinase+gamma+is+a+critical+mediator+of+myocardial+ischemic+and+adenosine-mediated+preconditioning.">Phosphatidylinositol 3-kinase gamma is a critical mediator of myocardial ischemic and adenosine-mediated preconditioning.</a> Circulation Research. 103 (6), 643-653 (2008).</li><li>Wu, Z. K., Iivainen, T., Pehkonen, E., Laurikka, J., Tarkka, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ischemic+preconditioning+suppresses+ventricular+tachyarrhythmias+after+myocardial+revascularization.">Ischemic preconditioning suppresses ventricular tachyarrhythmias after myocardial revascularization.</a> Circulation. 106 (24), 3091-3096 (2002).</li><li>Hausenloy, D. J., Yellon, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preconditioning+and+postconditioning:+underlying+mechanisms+and+clinical+application.">Preconditioning and postconditioning: underlying mechanisms and clinical application.</a> Atherosclerosis. 204 (2), 334-341 (2009).</li><li>Heusch, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+basis+of+cardioprotection:+signal+transduction+in+ischemic+pre-,+post-,+and+remote+conditioning.">Molecular basis of cardioprotection: signal transduction in ischemic pre-, post-, and remote conditioning.</a> Circulation Research. 116 (4), 674-699 (2015).</li><li>Lund, O., Emmertsen, K., Dorup, I., Jensen, F. T., Flo, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regression+of+left+ventricular+hypertrophy+during+10+years+after+valve+replacement+for+aortic+stenosis+is+related+to+the+preoperative+risk+profile.">Regression of left ventricular hypertrophy during 10 years after valve replacement for aortic stenosis is related to the preoperative risk profile.</a> European Heart Journal. 24 (15), 1437-1446 (2003).</li><li>Rockman, H. 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=Segregation+of+atrial-specific+and+inducible+expression+of+an+atrial+natriuretic+factor+transgene+in+an+in+vivo+murine+model+of+cardiac+hypertrophy.">Segregation of atrial-specific and inducible expression of an atrial natriuretic factor transgene in an in vivo murine model of cardiac hypertrophy.</a> Proceedings of the National Academy of Sciiences of the United States of America. 88 (18), 8277-8281 (1991).</li><li>Wei, X., 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=Myocardial+hypertrophic+preconditioning+attenuates+cardiomyocyte+hypertrophy+and+slows+progression+to+heart+failure+through+upregulation+of+S100A8/A9.">Myocardial hypertrophic preconditioning attenuates cardiomyocyte hypertrophy and slows progression to heart failure through upregulation of S100A8/A9.</a> Circulation. 131 (17), 1506-1517 (2015).</li><li>Huang, J., 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=Ultrasound+biomicroscopy+validation+of+a+murine+model+of+cardiac+hypertrophic+preconditioning:+comparison+with+a+hemodynamic+assessment.">Ultrasound biomicroscopy validation of a murine model of cardiac hypertrophic preconditioning: comparison with a hemodynamic assessment.</a> American Journal of Physiology. Heart and Circulatory Physiology. 313 (1), 138-148 (2017).</li><li>Oka, T., 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=Cardiac-specific+deletion+of+Gata4+reveals+its+requirement+for+hypertrophy,+compensation,+and+myocyte+viability.">Cardiac-specific deletion of Gata4 reveals its requirement for hypertrophy, compensation, and myocyte viability.</a> Circulation Research. 98 (6), 837-845 (2006).</li><li>Li, L., 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=Assessment+of+cardiac+morphological+and+functional+changes+in+mouse+model+of+transverse+aortic+constriction+by+echocardiographic+imaging.">Assessment of cardiac morphological and functional changes in mouse model of transverse aortic constriction by echocardiographic imaging.</a> Journal of Visualized Experiments. (112), e54101 (2016).</li><li>Veldhuizen, R. A., Slutsky, A. S., Joseph, M., McCaig, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+mechanical+ventilation+of+isolated+mouse+lungs+on+surfactant+and+inflammatory+cytokines.">Effects of mechanical ventilation of isolated mouse lungs on surfactant and inflammatory cytokines.</a> The European Respiratory Journal. 17 (3), 488-494 (2001).</li><li>Wang, Q., 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=Induction+of+right+ventricular+failure+by+pulmonary+artery+constriction+and+evaluation+of+right+ventricular+function+in+mice.">Induction of right ventricular failure by pulmonary artery constriction and evaluation of right ventricular function in mice.</a> Journal of Visualized Experiments. (147), e59431 (2019).</li><li>Eichhorn, L., 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=A+closed-chest+model+to+induce+transverse+aortic+constriction+in+mice.">A closed-chest model to induce transverse aortic constriction in mice.</a> Journal of Visualized Experiments. (134), e57397 (2018).</li><li>Tavakoli, R., Nemska, S., Jamshidi, P., Gassmann, M., Frossard, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Technique+of+minimally+invasive+transverse+aortic+constriction+in+mice+for+induction+of+left+ventricular+hypertrophy.">Technique of minimally invasive transverse aortic constriction in mice for induction of left ventricular hypertrophy.</a> Journal of Visualized Experiments. (127), e56231 (2017).</li></ol>

著者らは開示するものは何もない。

心臓非虚血予備調整には、依然として非常に未踏の領域があります。これまでの研究に基づき、吸収性縫合糸を使用して心筋肥大プリコンディショニングモデルを改善することに切り替えました。
以前の報告では、多くの研究者がシルク縫合糸を使用して大動脈弓8、14、15を収縮させました。シルク?...

虚血性プレコンディショニングは、虚血と心臓への再灌流の短い非致死的なエピソードを誘発する現象であり、心筋損傷を劇的に減少させる能力を有する1。心筋梗塞サイズ2の制限や心筋血管化後の心室頻脈不整脈の抑制など、虚血性プレコンディショニングの明らかな臨床的影響を考えると、プレコンディショニング4,5によって誘発される心臓保護効果のメカニズムを解剖する研究が多い。対照的に、他の非虚血型のプレコンディショニングは比較的注目されていない。心臓肥大は、大動脈弁置換術6を受けている大動脈狭窄症の患者において鈍化し得る。病理学的心筋肥大の状態が存在するところはどこでも、プレコンディショニングの原理はほとんど報告されない。
1991年、ロックマンらは、まず横大動脈収縮(TAC)7により左心室肥大のマウスモデルを確立した。マウスでTACを2回操作することにより、心筋肥大型プレコンディショニング(MHP)が心臓の一過性肥大刺激につながることが以前に証明され、それによって心臓は将来の持続的な肥大性ストレスに対してより耐性を高める8。MHPモデルの特性は、超音波バイオ顕微鏡と血行力学的評価9によって検証されています。モデルを構築する際の重要なポイントは、3回の経術術、1週間のTAC、1週間のデバンディング、および6週間の二次TACを行うことであった。しかし、デベンディングは出血を引き起こす可能性があり、初心者によって習得されにくく、普及することは困難でした。また、マウスを挿管することは技術的な課題でもあります。不適切な挿管は、気管損傷、気胸、さらにはマウスの死を引き起こす可能性があります。したがって、MHPモデルを構築しながら、いくつかの手順を改善することが必要であり、価値があります。
モデルの難易度を軽減し、その成功を高めるために、我々は最初のTACのための吸収可能な縫合線に切り替え、心エコー検査10の下で大動脈収縮の間の圧力勾配を測定することによってモデルの成功を監視した。我々の予備実験に基づいて、あまりにも低圧勾配のマウスに十分な心筋肥大を誘発することは困難であり、高圧勾配が高すぎるマウスは急性心不全を発症するか死ぬことさえある。モデルの理想的な圧力勾配は40-80 mmHg11から範囲。さらに、この実験は人工呼吸器に頼らず、人工呼吸器関連の技術的操作や傷害を効果的に回避できる12.

<table>
	<tbody>
		<tr>
			<td>Absorbable suture (5-0)</td>
			<td>Shandong Kang Lida Medical Products Co., Ltd</td>
			<td>5-0</td>
			<td>Ligation</td>
		</tr>
		<tr>
			<td>Animal ultrasound system VEVO2100</td>
			<td>Visual Sonic</td>
			<td>VEVO2100</td>
			<td>Echocardiography</td>
		</tr>
		<tr>
			<td>Cold light illuminator</td>
			<td>Olympus</td>
			<td>ILD-2</td>
			<td>Light</td>
		</tr>
		<tr>
			<td>Heat pad- thermostatic surgical system (ALC-HTP-S1)</td>
			<td>SHANGHAI ALCOTT BIOTECH CO</td>
			<td>ALC-HTP-S1</td>
			<td>Heating</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>RWD life science</td>
			<td>R510-22</td>
			<td>Inhalant anaesthesia</td>
		</tr>
		<tr>
			<td>Matrx VIP 3000 Isofurane Vaporizer</td>
			<td>Midmark Corporation</td>
			<td>VIP 3000</td>
			<td>Anesthetization</td>
		</tr>
		<tr>
			<td>Medical nylon suture (5-0)</td>
			<td>Ningbo Medical Needle Co.</td>
			<td>5-0</td>
			<td>Close the skin</td>
		</tr>
		<tr>
			<td>Pentobarbital sodium salt</td>
			<td>Merck</td>
			<td>25MG</td>
			<td>Anesthetization</td>
		</tr>
		<tr>
			<td>Precision electronic balance</td>
			<td>Denver Instrument</td>
			<td>TB-114</td>
			<td>Weighing sensor</td>
		</tr>
		<tr>
			<td>Self-made spacer</td>
			<td></td>
			<td></td>
			<td>25-gauge needle</td>
		</tr>
		<tr>
			<td>Silk suture (5-0)</td>
			<td>Yangzhou Yuankang Medical Devices Co., Ltd.</td>
			<td>5-0</td>
			<td>Ligation</td>
		</tr>
		<tr>
			<td>Small animal microsurgery equipment</td>
			<td>Napox</td>
			<td>MA-65</td>
			<td>Surgical instruments</td>
		</tr>
		<tr>
			<td>Transmission Gel</td>
			<td>Guang Gong pai</td>
			<td>250ML</td>
			<td>Echocardiography</td>
		</tr>
		<tr>
			<td>Veet hair removal cream</td>
			<td>Reckitt Benchiser</td>
			<td>RQ/B 33 Type 2</td>
			<td>Remove hair of mice</td>
		</tr>
		<tr>
			<td>Vertical automatic electrothermal pressure steam sterilizer</td>
			<td>Hefei Huatai Medical Equipment Co.</td>
			<td>LX-B50L</td>
			<td>Auto clean the surgical instruments</td>
		</tr>
	</tbody>
</table>

operating transverse aortic constriction with absorbable suture to obtain transient myocardial hypertrophy

マウスの2回横筋狭窄(TAC)に基づいて、心筋肥大前調整(MHP)が心筋細胞肥大を減衰させ、心不全への進行を遅らせることができることが証明されています。しかし、初心者にとって、MHPモデルは、人工呼吸器の操作における技術的な障害、胸部の繰り返し開き、およびデパンディングによる出血のために確立することは通常非常に困難である。このモデルを容易にするために、外科的成功率を高め、出血の発生率を減少させるために、人工呼吸器のない技術を用いた最初のTACコーミングのための吸収可能な縫合糸に切り替えた。2週間の吸収性縫合糸を用いて、この手順が2週間で重大な心筋肥大を引き起こす可能性があることを実証した。そして手術後4週間、心筋肥大はほぼ完全にベースラインに後退した。このプロトコルを使用すると、オペレータは、より低い操作死亡率でMHPモデルを簡単に習得することができます。

本研究では、45匹のマウスを無作為に、シャム、シルク縫合糸群、および吸収性縫合グループ(D0(ベースライン)、D14、D28後の各群の数をそれぞれ15、10、および5に分割した。手術後のD7、D14、D21、およびD28では、収縮したピーク速度を心エコー検査によって決定した。吸収性の縫合糸を使用して大動脈弓を収縮させたにもかかわらず、TACの後の第2週に収縮時の血流速度は依然として3,000mm/sを超?...

Watch this Scientific Journal Video about Operating Transverse Aortic Constriction with Absorbable Suture to Obtain Transient Myocardial Hypertrophy at JoVE.com

Operating Transverse Aortic Constriction with Absorbable Suture to Obtain Transient Myocardial Hypertrophy

このプロトコルは、吸収性縫合糸を有する一過性心筋肥大を得るための改善された方法を提示し、圧力過負荷を除去した後に減少した左心室肥大をシミュレートする。これは、心筋肥大型プレコンディショニングに関する研究のために貴重な可能性があります。.

過渡性心筋肥大を得るために吸収性縫合を用いて横方向の大動脈収縮を操作する

Based on twice transverse aortic constrictions (TACs) in mice, it is proved that myocardial hypertrophic preconditioning (MHP) could attenuate ...

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Research

JoVE Journal

Medicine

6.2K ビュー.  Southern Medical University. このプロトコルは、吸収性縫合糸を有する一過性心筋肥大を得るための改善された方法を提示し、圧力過負荷を除去した後に減少した左心室肥大をシミュレートする。これは、心筋肥大型プレコンディショニングに関する研究のために貴重な可能性があります。.

ビデオ: Operating Transverse Aortic Constriction with Absorbable Suture to Obtain Transient Myocardial Hypertrophy

A Research Method For Detecting Transient Myocardial Ischemia In Patients With Suspected Acute Coronary Syndrome Using Continuous ST-segment Analysis

Each year, an estimated 785,000 Americans will have a new coronary attack, or acute coronary syndrome (ACS). The pathophysiology of ACS involves rupture of an atherosclerotic plaque; hence, treatment is aimed at plaque stabilization in order to prevent cellular death. However, there is considerable debate among clinicians, about which treatment pathway is best: early invasive using percutaneous coronary intervention (PCI/stent) when indicated or a conservative approach (i.e., medication only with PCI/stent if recurrent symptoms occur).
There are three types of ACS: ST elevation myocardial infarction (STEMI), non-ST elevation MI (NSTEMI), and unstable angina (UA). Among the three types, NSTEMI/UA is nearly four times as common as STEMI. Treatment decisions for NSTEMI/UA are based largely on symptoms and resting or exercise electrocardiograms (ECG). However, because of the dynamic and unpredictable nature of the atherosclerotic plaque, these methods often under detect myocardial ischemia because symptoms are unreliable, and/or continuous ECG monitoring was not utilized.
Continuous 12-lead ECG monitoring, which is both inexpensive and non-invasive, can identify transient episodes of myocardial ischemia, a precursor to MI, even when asymptomatic. However, continuous 12-lead ECG monitoring is not usual hospital practice; rather, only two leads are typically monitored. Information obtained with 12-lead ECG monitoring might provide useful information for deciding the best ACS treatment.
Purpose. Therefore, using 12-lead ECG monitoring, the COMPARE Study (electroCardiographic evaluatiOn of ischeMia comParing invAsive to phaRmacological trEatment) was designed to assess the frequency and clinical consequences of transient myocardial ischemia, in patients with NSTEMI/UA treated with either early invasive PCI/stent or those managed conservatively (medications or PCI/stent following recurrent symptoms). The purpose of this manuscript is to describe the methodology used in the COMPARE Study.
Method. Permission to proceed with this study was obtained from the Institutional Review Board of the hospital and the university. Research nurses identify hospitalized patients from the emergency department and telemetry unit with suspected ACS. Once consented, a 12-lead ECG Holter monitor is applied, and remains in place during the patient's entire hospital stay. Patients are also maintained on the routine bedside ECG monitoring system per hospital protocol. Off-line ECG analysis is done using sophisticated software and careful human oversight.

Continuous 12-lead electrocardiographic (ECG) monitoring can identify transient myocardial ischemia, even when asymptomatic, among patients with suspected acute coronary syndrome (ACS). In this article we describe our method for initiating patient monitoring using a Holter device, downloading the ECG data for off-line analysis, and how to utilize the ECG software to identify transient ischemia.

連続ST部分の解析を使用した疑いのある急性冠症候群（ACS）患者において一過性心筋虚血を検出するための研究法

Each year, an estimated 785,000 Americans will have a new coronary attack, or acute coronary syndrome (ACS). The pathophysiology of ACS involves rupture ...

医学

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

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

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

圧負荷心肥大モデルの作成のためのラットの大動脈狭窄昇順

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

Murine Isolated Heart Model of Myocardial Stunning Associated with Cardioplegic Arrest

The following protocol is of use to evaluate impaired cardiac function or myocardial stunning following moderate ischemic insults. The technique is useful for modeling ischemic injury associated with numerous clinically relevant phenomenon including cardiac surgery with cardioplegic arrest and cardiopulmonary bypass, off-pump CABG, transplant, angina, brief ischemia, etc. The protocol presents a general method to model hypothermic hyperkalemic cardioplegic arrest and reperfusion in rodent hearts focusing on measurement of myocardial contractile function. In brief, a mouse heart is perfused in langendorff mode, instrumented with an intraventricular balloon, and baseline cardiac functional parameters are recorded. Following stabilization, the heart is then subject to brief infusion of a cardioprotective hypothermic cardioplegia solution to initiate diastolic arrest. Cardioplegia is delivered intermittently over 2 hr. The heart is then reperfused and warmed to normothermic temperatures and recovery of myocardial function is monitored. Use of this protocol results in reliable depressed cardiac contractile function free from gross myocardial tissue damage in rodents.

The goal of this protocol to assess myocardial stunning following ischemic cardioplegic arrest in rodents.

心臓麻痺逮捕と気絶心筋関連のマウス単離された心臓モデル

The following protocol is of use to evaluate impaired cardiac function or myocardial stunning following moderate ischemic insults. The technique is useful ...

Assessment of Cardiac Morphological and Functional Changes in Mouse Model of Transverse Aortic Constriction by Echocardiographic Imaging

Transverse aortic constriction (TAC) in mice has been used as a valuable model to study mechanisms of cardiac hypertrophy and heart failure1. A reliable noninvasive method is essential to assess real-time cardiac morphological and functional changes in animal models of heart disease. Transthoracic echocardiography represents an important tool for noninvasive assessment of cardiac structure and function2. Here we used a high-resolution ultrasound imaging system to monitor myocardial remodeling and heart failure progression over time in a mouse model of TAC. B-mode, M-mode, and Doppler imaging were used to precisely assess cardiac hypertrophy, ventricular dilatation, and functional deterioration in mice following TAC. Color and pulse wave (PW) Doppler imaging was used to noninvasively measure pressure gradient across the aortic constriction created by TAC and to assess transmitral blood flow in mice. Thus transthoracic echocardiographic imaging provides comprehensive noninvasive measurements of cardiac dimensions and function in mouse models of heart disease.

The goal of this protocol is to noninvasively assess cardiac structural and functional changes in a mouse model of heart disease created by transverse aortic constriction, using B- and M-mode echocardiography and color/pulse wave Doppler imaging.

心臓形態学的および心エコーイメージングによって横大動脈狭窄のマウスモデルにおける機能の変更の評価

Transverse aortic constriction (TAC) in mice has been used as a valuable model to study mechanisms of cardiac hypertrophy and heart failure1. A reliable ...

Minimally Invasive Transverse Aortic Constriction in Mice

Minimally invasive transverse aortic constriction (MTAC) is a more desirable method for the constriction of the transverse aorta in mice than standard open-chest transverse aortic constriction (TAC). Although transverse aortic constriction is a highly functional method for the induction of high pressure in the left ventricle, it is a more difficult and lengthy procedure due to its use of artificial ventilation with tracheal intubation. TAC is oftentimes also less survivable, as the newer method, MTAC, neither requires the cutting of the ribs and intercostal muscles nor tracheal intubation with a ventilation setup. In MTAC, as opposed to a thoracotomy to access to the chest cavity, the aortic arch is reached through a midline incision in the anterior neck. The thyroid is pulled back to reveal the sternal notch. The sternum is subsequently cut down to the second rib level, and the aortic arch is reached simply by separating the connective tissues and thymus. From there, a suture can be wrapped around the arch and tied with a spacer, and then the sternal cut and skin can be closed. MTAC is a much faster and less invasive way to induce left ventricular hypertension and enables the possibility for high-throughput studies. The success of the constriction can be verified using high-frequency trans-thoracic echocardiography, particularly color Doppler and pulsed-wave Doppler, to determine the flow velocities of the aortic arch and left and right carotid arteries, the dimension of the blood vessels, and the left ventricular function and morphology. A successful constriction will also trigger significant histopathological changes, such as cardiac muscle cell hypertrophy with interstitial and perivascular fibrosis. Here, the procedure of MTAC is described, demonstrating how the resulting flow changes in the carotid arteries can be examined with echocardiography, gross morphology, and histopathological changes in the heart.

Minimally invasive transverse aortic constriction (MTAC) conserves the essentials of regular transverse aortic constriction (TAC) while eliminating the use of a ventilator with tracheal intubation. It proves to be a highly desirable method for high-throughput studies on left ventricular overload, particularly in translational studies.

マウスにおける低侵襲横大動脈狭窄

Minimally invasive transverse aortic constriction (MTAC) is a more desirable method for the constriction of the transverse aorta in mice than standard ...

Full-root Aortic Valve Replacement by Stentless Aortic Xenografts in Patients with Small Aortic Roots

In patients with small aortic roots who need an aortic valve replacement with biological valve substitutes, the implantation of the stented pericardial valve might not meet the functional needs. The implantation of a too-small stented pericardial valve, leading to an effective orifice area indexed to a body surface area less than 0.85 cm2/m2, is regarded as prosthesis-patient mismatch (PPM). A PPM negatively affects the regression of left ventricular hypertrophy and thus the normalization of left ventricular function and the alleviation of symptoms. Persistent left ventricular hypertrophy is associated with an increased risk of arrhythmias and sudden cardiac death. In the case of predictable PPM, there are three options: 1) accept the PPM resulting from the implantation of a stented pericardial valve when comorbidities of the patient forbid the more technically demanding operative technique of implanting a larger prosthesis, 2) enlarge the aortic root to accommodate a larger stented valve substitute, or 3) implant a stentless biological valve or a homograft. Compared to classical aortic valve replacement with stented pericardial valves, the full-root implantation of stentless aortic xenografts offers the possibility of implanting a 3-4 mm larger valve in a given patient, thus allowing significant reduction in transvalvular gradients. However, a number of cardiac surgeons are reluctant to transform a classical aortic valve replacement with stented pericardial valves into the more technically challenging full-root implantation of stentless aortic xenografts. Given the potential hemodynamic advantages of stentless aortic xenografts, we have adopted full-root implantation to avoid PPM in patients with small aortic roots necessitating an aortic valve replacement. Here, we describe in detail a technique for the full-root implantation of stentless aortic xenografts, with emphasis on the management of the proximal suture line and coronary anastomoses. Limitations of this technique and alternative options are discussed.

Full-root aortic valve replacement by stentless aortic xenograft is a viable option in patients with small aortic roots. We describe, a technique for the full-root implantation of stentless aortic xenografts, with emphasis on the management of the proximal suture line and coronary anastomoses, and discuss its limitations and alternative options.

小型大動脈瘤患者におけるステントレス大動脈異種移植による全大動脈弁置換術

In patients with small aortic roots who need an aortic valve replacement with biological valve substitutes, the implantation of the stented pericardial ...

Technique of Minimally Invasive Transverse Aortic Constriction in Mice for Induction of Left Ventricular Hypertrophy

Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure overload-induced left ventricular hypertrophy (LVH) and its progression to heart failure. In the majority of the reported investigations, this procedure is performed with intubation and ventilation of the animal which renders it demanding and time-consuming and adds to the surgical burden to the animal. The aim of this protocol is to describe a simplified technique of minimally invasive TAC without intubation and ventilation of mice. Critical steps of the technique are emphasized in order to achieve low mortality and high efficiency in inducing LVH.
Male C57BL/6 mice (10-week-old, 25-30 g, n=60) were anesthetized with a single intraperitoneal injection of a mixture of ketamine and xylazine. In a spontaneously breathing animal following a 3-4 mm upper partial sternotomy, a segment of 6/0 silk suture threaded through the eye of a ligation aid was passed under the aortic arch and tied over a blunted 27-gauge needle. Sham-operated animals underwent the same surgical preparation but without aortic constriction. The efficacy of the procedure in inducing LVH is attested by a significant increase in the heart/body weight ratio. This ratio is obtained at days 3, 7, 14 and 28 after surgery (n = 6 - 10 in each group and each time point). Using our technique, LVH is observed in TAC compared to sham animals from day 7 through day 28. Operative and late (over 28 days) mortalities are both very low at 1.7%.
In conclusion, our cost-effective technique of minimally invasive TAC in mice carries very low operative and post-operative mortalities and is highly efficient in inducing LVH. It simplifies the operative procedure and reduces the strain put on the animal. It can be easily performed by following the critical steps described in this protocol.

The aim of this protocol is to describe step-by-step the technique of minimally invasive transverse aortic constriction (TAC) in mice. By elimination of intubation and ventilation which are mandatory for the commonly used standard procedure, minimally invasive TAC simplifies the operative procedure and reduces the strain put on the animal.

左室肥大の誘導マウスにおける低侵襲の横大動脈狭窄のテクニック

Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure ...

A Closed-chest Model to Induce Transverse Aortic Constriction in Mice

Research on cardiac hypertrophy and heart failure is frequently based on pressure overload mouse models induced by TAC. The standard procedure is to perform a partial thoracotomy to visualize the transverse aortic arch. However, the surgical trauma caused by the thoracotomy in open-chest models changes the respiratory physiology as the ribs are dissected and left unattached after chest closure. To prevent this, we established a minimally invasive, closed chest approach via lateral thoracotomy. Herein we approach the aortic arch via the 2nd intercostal space without entering the chest cavities, leaving the mouse with a less traumatic injury to recover from. We perform this operation using standard laboratory settings for open chest TAC procedures with equal survival rates. Apart from maintaining physiological breathing patterns due to the closed chest approach, the mice seem to benefit by showing rapid recovery, as the less invasive technique appears to facilitate a fast healing process and to reduce immune response after trauma.

Here, we present a protocol of Transverse Aortic constriction (TAC) via a lateral thoracotomy. This technique is a minimally invasive, closed chest surgical procedure aiming to simulate pressure overload and heart failure in mice utilizing standard TAC laboratory settings.

マウスで横方向の大動脈狭窄を誘導するために閉じて胸モデル

Research on cardiac hypertrophy and heart failure is frequently based on pressure overload mouse models induced by TAC. The standard procedure is to ...

Murine Cervical Aortic Transplantation Model using a Modified Non-Suture Cuff Technique

With the introduction of powerful immunosuppressive protocols, distinct advances are possible in the prevention and therapy of acute rejection episodes. However, only minor improvement in the long-term results of transplanted solid organs could be observed over the past decades. In this context, chronic allograft vasculopathy (CAV) still represents the leading cause of late organ failure in cardiac, renal and pulmonary transplantation.
Thus far, the underlying pathogenesis of CAV development remains unclear, explaining why effective treatment strategies are presently missing and emphasizing a need for relevant experimental models in order to study the underlying pathophysiology leading to CAV formation. The following protocol describes a murine heterotopic cervical aortic transplantation model using a modified non-suture cuff technique. In this technique, a segment of the thoracic aorta is interpositioned in the right common carotid artery. With the use of the non-suture cuff technique, an easy to learn and reproducible model can be established, minimizing the possible heterogeneity of sutured vascular micro anastomoses.

Here, we present a protocol of heterotopic aortic transplantation in mice using the non-suture cuff technique in a cervical murine model. This model can be used to study the underlying pathology of chronic allograft vasculopathy (CAV) and can help evaluate new therapeutic agents in order to prevent its formation.

改変非縫合カフ技術を用いたマウス子宮頸動脈大動脈移植モデル

With the introduction of powerful immunosuppressive protocols, distinct advances are possible in the prevention and therapy of acute rejection episodes. ...

Using Q Suture to Enhance Resistance to Gap Formation and Tensile Strength of Repaired Flexor Tendons

Peripheral epitendinous sutures are believed to enhance core suture strength in tendon repair and decrease the risk of gapping between tendon ends. Here Q suture, an alternative to peripheral sutures, is presented for the use in tendon repair. Its effects on gap formation and tensile strength of the repaired tendons were compared with conventional running peripheral sutures. Three 2-strand sutures and three 4-strand sutures were used in repairing porcine tendons. The time required for performing 2Q and running sutures were recorded. The repaired tendons were subjected to a cyclic loading test, and the cycle number, during which a 2-mm gap was formed, was determined. After the cyclic loading, the gap size at the tendon ends and the ultimate strength of the repaired tendons were measured. Augmentation with the Q sutures reduced the number of tendons showing 2-mm gaps at tendon ends during cyclic loading. With addition of Q sutures 2-strand sutures significantly increased the ultimate strength of the repaired tendons and 4-strand sutures decreased the gap distance at the repair site of tendons. The time required for performing 2Q sutures was significantly less than that for running sutures. Therefore, we conclude that the Q suture is efficient in enhancing the tensile resistance and tendon repair strength and can be an alternative to conventional peripheral sutures.

Here, we present a &#8220;Q&#8221; suture technique that can be performed in tendon repair and its effects on the gap formation and tensile strength of the repaired tendons. Q suture is shown to be efficient in enhancing the tensile resistance and tendon repair strength.

Q縫合糸を用いて、修復された屈曲腱のギャップ形成と引張強度に対する耐性を高める

Peripheral epitendinous sutures are believed to enhance core suture strength in tendon repair and decrease the risk of gapping between tendon ends. Here Q ...