المؤلفون ممتنون لSchipke شاد وChesser دانيال لمساعدتهم في تصميم وتصنيع هذا النظام ومايلز Valtresa للمساعدة في إعداد مخطوطة.

1. حصاد الأنسجة والتحضير <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> وينبغي جمع صمامات الأبهر من الخنازير البالغين وزنها لا يزيد عن 120 £ على الفور بعد الموت. </li><li style=";text-align:right;direction:rtl"> غسل الصمامات مرتين مع الفوسفات العقيمة مخزنة المالحة (PBS) والنقل إلى المختبر على الجليد. </li><li style=";text-align:right;direction:rtl"> يجب أن يتم تنفيذ جميع الخطوات اللاحقة في ظل ظروف معقمة. </li><li style=";text-align:right;direction:rtl"> تأكد من أن المنشورات لا تظهر أي علامة على انحطاط ، وتمزيق أو التكلس. إزالة المناشير من جذر الأبهر عن طريق قطع 1 / 3 من المسافة من الحلقة. </li><li style=";text-align:right;direction:rtl"> منشورات المركز في الآبار الفردية لوحة six جيدا واحتضان بين عشية وضحاها مع متوسطة 3ml Dulbecco في النسر التعديل تستكمل مع حل anti-biotic/anti-mycotic 1 ٪ و 10 ٪ في مصل بقري جنيني من 37 درجة مئوية و 5 ٪ CO 2. </li><li style=";text-align:right;direction:rtl"> كما يمكن أن تكون بديلا المصنف ، والخلايا المعزولة في لوحات ثقافة ستة جيدا وتستخدم في جهاز الضغط. لا يمكن أن يؤديها عزل الخلايا البطانية وخلايا صمام خلالي كما هو موضح سابقا 13 و 14. </li></ol> 2. الضغط الدراسات <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> وقد تم تصميم نظام الضغط مصنوعة خصيصا لدراسة آثار mechanobiological دوري للضغط على أنسجة الصمام الأبهر 15. </li><li style=";text-align:right;direction:rtl"> تسجيل الدخول إلى جهاز الكمبيوتر وفتح البرنامج LABVIEW (الشكل 1). </li><li style=";text-align:right;direction:rtl"> المعايرة : <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> قبل التجريب ، ينبغي أن يكون نظام معايرة بشكل صحيح. </li><li style=";text-align:right;direction:rtl"> توصيل التيار الكهربائي إلى لوحة الدائرة. وهذا يوفر الطاقة إلى الملف اللولبي الصمامات التي تتحكم في تدفق الهواء إلى داخل وخارج القاعة. </li><li style=";text-align:right;direction:rtl"> تأكد من توصيل الهواء المضغوط للنظام وفتح العرض الجوي لسرعة الكامل. </li><li style=";text-align:right;direction:rtl"> تشغيل مكبر إشارة. تأكد من قراءة الجهد هو 0.00. ضبط حسب الضرورة </li><li style=";text-align:right;direction:rtl"> واجهة LABVIEW وتبديل وضع علامة &quot;TEST / محضر&quot;. تأكد من تعيين رمز التبديل إلى &quot;اختبار&quot;. انقر على زر &quot;آير التموين&quot; لفتح صمام الملف اللولبي المدخل. </li><li style=";text-align:right;direction:rtl"> باستخدام منظم ضغط الغاز ، مع الضغط على غرفة الهواء المضغوط في 1 PSI. يمكن قراءة الضغط في الغرفة باستخدام مقياس الضغط الرقمي الموجود على الجزء الخلفي نهاية لوحة للغرفة. بمجرد الضغط ومعايرتها وسجل القراءة الجهد من مكبر للصوت إشارة. كرر لPSI 2 و 3 و 4 و 5. </li><li style=";text-align:right;direction:rtl"> بناء منحنى معايرة ضغط مقابل الجهد. وينبغي تحويلها إلى ضغوط من PSI مم زئبق. يمكن وضعها في المعادلة من الرسم إلى رمز للبرنامج LABVIEW </li></ol></li><li style=";text-align:right;direction:rtl"> إزالة اللوحة الأمامية الألومنيوم من غرفة الضغط ورش الغرفة مع الايثانول 70 ٪. إجازة لمدة لا تقل عن 10 دقيقة للسماح للأبخرة الإيثانول المتبقية لتبدد. </li><li style=";text-align:right;direction:rtl"> مكان لوحة سداسية كذلك تحتوي على عينات من النشرة الى غرفة واستبدال لوحة أمامية. ضمان الختم هو محكم من خلال تشديد المكسرات الموجودة على قضبان مترابطة four (الموجود في كل زاوية من لوحة النهاية) باليد. المكان غرفة الضغط في الحاضنة 37 درجة مئوية. ويظهر رسم تخطيطي للغرفة الضغط في الشكل 2. </li><li style=";text-align:right;direction:rtl"> فإن واجهة المستخدم موجه لتوفير مقدار الوقت دورات النظام بين المدخلات والمخرجات الهواء المضغوط. يجب تعيين هذه إلى و0.6s 0.4s لمحاكاة الظروف الانقباضي الانبساطي و، على التوالي ، على تردد 1Hz. يجب على المستخدم أيضا إدخال مسار ملف البيانات. </li><li style=";text-align:right;direction:rtl"> في LABVIEW ، انقر فوق تشغيل وتبديل &quot;TEST / محضر&quot; تبديل إلى &quot;السجل&quot;. </li><li style=";text-align:right;direction:rtl"> تأكد من أن الضغط على المستوى المطلوب باستخدام الرسم على واجهة LABVIEW. يمكن ضبط الضغط باستخدام منظم ضغط الغاز. </li><li style=";text-align:right;direction:rtl"> تشغيل البرنامج لمدة من الوقت المطلوب. </li><li style=";text-align:right;direction:rtl"> بمجرد اكتمال التجربة ، انقر فوق الزر إيقاف على LABVIEW ، وإيقاف العرض الجوي وفتح صمام العادم في غرفة الضغط. </li><li style=";text-align:right;direction:rtl"> إزالة اللوحة الأمامية من الغرفة وجلب عينات لوحة تحتوي على ستة جيدا. ويمكن الآن أن تحلل عينات للتعبير الجينات ، والتعبير البروتين ، والأنسجة ، الخصائص الميكانيكية الخ. </li></ol> 3. ممثل النتائج : نظام ضغط قادرة على محاكاة أقصى الضغوط لوحظ تحت transvalvular normotensive ، المرحلة الأولى وارتفاع ضغط الدم ظروف المرحلة الثانية. ومع ذلك ، كان الضغط غير قادرة على محاكاة التدرج الضغط الانقباضي ، وهو أساسا صفر في الجسم الحي. الحفاظ على وتيرة 1Hz ، مع مدخل الهواء 0.6s الوقت والوقت عوادم 0.4s. ويمكن رؤية ممثل الطول الموجي ضغط ظروف الضغط العادية ومرتفعة تم الحصول عليها من هذا النظام في الشكل 3. <img src="/files/ftp_upload/3316/3316fig1.jpg" alt="الشكل 1"/> الشكل 1 : لقطة الشاشة واجهة ابفيو (LabVIEW). <img src="/files/ftp_upload/3316/3316fig2.jpg" alt="الشكل 2"/> الشكل 2 : رسم تخطيطي لعرض ألف غرفة الضغط متساوي القياس من غرفة الضغط ؛ باء عرض الجانبية للغرفة الضغط ؛C. عرض أعلى غرفة الضغط. <img src="/files/ftp_upload/3316/3316fig3.jpg" alt="الشكل 3"/> الشكل 3 : رسم بياني لمحاكاة الضغط داخل حجرة الضغط على (A) normotensive ، (ب) المرحلة الأولى ارتفاع ضغط الدم ، و (C) المرحلة الثانية ظروف ارتفاع ضغط الدم.

<ol>
	<li>Freeman, R. V., Otto, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spectrum+of+calcific+aortic+valve+disease:+pathogenesis,+disease+progression,+and+treatment+strategies.">Spectrum of calcific aortic valve disease: pathogenesis, disease progression, and treatment strategies.</a> Circulation. 111, 3316-3326 (2005).</li><li>Robicsek, F., Thubrikar, M. J., Fokin, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cause+of+degenerative+disease+of+the+trileaflet+aortic+valve:+review+of+subject+and+presentation+of+a+new+theory.">Cause of degenerative disease of the trileaflet aortic valve: review of subject and presentation of a new theory.</a> Ann Thorac Surg. 73, 1346-1354 (2002).</li><li>Thubrikar, M. J., Aouad, J., Nolan, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patterns+of+calcific+deposits+in+operatively+excised+stenotic+or+purely+regurgitant+aortic+valves+and+their+relation+to+mechanical+stress.">Patterns of calcific deposits in operatively excised stenotic or purely regurgitant aortic valves and their relation to mechanical stress.</a> Am J Cardiol. 58, 304-308 (1986).</li><li>Agno, F. S., Chinali, M., Bella, J. N., Liu, J. E., Arnett, D. K., Kitzman, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aortic+valve+sclerosis+is+associated+with+preclinical+cardiovascular+disease+in+hypertensive+adults:+the+Hypertension+Genetic+Epidemiology+Network+study.">Aortic valve sclerosis is associated with preclinical cardiovascular disease in hypertensive adults: the Hypertension Genetic Epidemiology Network study.</a> J Hypertens. 23, 867-8673 (2005).</li><li>Cawley, P. J., Otto, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prevention+of+calcific+aortic+valve+stenosis+-+fact+or+fiction.">Prevention of calcific aortic valve stenosis - fact or fiction.</a> Annals of Medicine. 41, 100-108 (2009).</li><li>Durst, C. A., Grande-Allen, J. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+and+physical+characterization+of+a+synchronous+multivalve+aortic+valve+culture+system.">Design and physical characterization of a synchronous multivalve aortic valve culture system.</a> Ann Biomed Eng. 38, 319-3125 (2010).</li><li>Engelmayr, G. C., Soletti, L., Vigmostad, S. C., Budilarto, S. G., Federspiel, W. J., Chandran, K. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+flex-stretch-flow+bioreactor+for+the+study+of+engineered+heart+valve+tissue+mechanobiology.">A novel flex-stretch-flow bioreactor for the study of engineered heart valve tissue mechanobiology.</a> Ann Biomed Eng. 36, 700-712 (2008).</li><li>Sucosky, P., Padala, M., Elhammali, A., Balachandran, K., Jo, H., Yoganathan, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+of+an+ex+vivo+culture+system+to+investigate+the+effects+of+shear+stress+on+cardiovascular+tissue.">Design of an ex vivo culture system to investigate the effects of shear stress on cardiovascular tissue.</a> J Biomech Eng. 130, 035001-03 (2008).</li><li>Syedain, Z. H., Tranquillo, R. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlled+cyclic+stretch+bioreactor+for+tissue-engineered+heart+valves.">Controlled cyclic stretch bioreactor for tissue-engineered heart valves.</a> Biomaterials. 30, 4078-4084 (2009).</li><li>Lagana, K., Moretti, M., Dubini, G., Raimondi, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+bioreactor+for+the+controlled+application+of+complex+mechanical+stimuli+for+cartilage+tissue+engineering.">A new bioreactor for the controlled application of complex mechanical stimuli for cartilage tissue engineering.</a> Proc Inst Mech Eng H. 222, 705-715 (2008).</li><li>Wartella, K. A., Wayne, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioreactor+for+biaxial+mechanical+stimulation+to+tissue+engineered+constructs.">Bioreactor for biaxial mechanical stimulation to tissue engineered constructs.</a> J Biomech Eng. 131, 044501-044501 (2009).</li><li>Wallis, M. C., Yeger, H., Cartwright, L., Shou, Z., Radisic, M., Haig, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Feasibility+study+of+a+novel+urinary+bladder+bioreactor.">Feasibility study of a novel urinary bladder bioreactor.</a> Tissue Eng Part A. 14, 339-348 (2008).</li><li>Butcher, J. T., Nerem, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Valvular+endothelial+cells+regulate+the+phenotype+of+interstitial+cells+in+co-culture:+effects+of+steady+shear+stress.">Valvular endothelial cells regulate the phenotype of interstitial cells in co-culture: effects of steady shear stress.</a> Tissue Eng. 12, 905-915 (2006).</li><li>Metzler, S. A., Pregonero, C. A., Butcher, J. T., Burgess, S. C., Warnock, J. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cyclic+Strain+Regulates+Pro-Inflammatory+Protein+Expression+in+Porcine+Aortic+Valve+Endothelial+Cells.">Cyclic Strain Regulates Pro-Inflammatory Protein Expression in Porcine Aortic Valve Endothelial Cells.</a> J Heart Valve Dis. 17, 571-578 (2008).</li><li>Schipke, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Design of a cyclic pressure bioreactor for the ex vivo study of aortic heart valve mechanobiology. , (2008).</li><li>Smith, K. E., Metzler, S. A., Warnock, J. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cyclic+strain+inhibits+acute+pro-inflammatory+gene+expression+in+aortic+valve+interstitial+cells.">Cyclic strain inhibits acute pro-inflammatory gene expression in aortic valve interstitial cells.</a> Biomechanics and Modeling in Mechanobiology. , (2009).</li><li>Warnock, J. N., Burgess, S. C., Shack, A., Yoganathan, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+immediate-early+gene+responses+to+elevated+pressure+in+porcine+aortic+valve+interstitial+cells.">Differential immediate-early gene responses to elevated pressure in porcine aortic valve interstitial cells.</a> J Heart Valve Dis. 15, 34-41 (2006).</li><li>Brathwaite, D., Weissman, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+new+onset+of+atrial+arrhythmias+following+major+noncardiothoracic+surgery+is+associated+with+increased+mortality.">The new onset of atrial arrhythmias following major noncardiothoracic surgery is associated with increased mortality.</a> Chest. 114, 462-468 (1998).</li><li>Walsh, S. R., Oates, J. E., Anderson, J. A., Blair, S. D., Makin, C. A., Walsh, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Postoperative+arrhythmias+in+colorectal+surgical+patients:+incidence+and+clinical+correlates.">Postoperative arrhythmias in colorectal surgical patients: incidence and clinical correlates.</a> Colorectal Dis. 8, 212-216 (2006).</li><li>Walsh, S. R., Tang, T., Gaunt, M. E., Schneider, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+arrhythmias+after+non-cardiothoracic+surgery.">New arrhythmias after non-cardiothoracic surgery.</a> BMJ. 7, 333-333 (2006).</li><li>Walsh, S. R., Tang, T., Wijewardena, C., Yarham, S. I., Boyle, J. R., Gaunt, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Postoperative+arrhythmias+in+general+surgical+patients.">Postoperative arrhythmias in general surgical patients.</a> Ann R Coll Surg Engl. 89, 91-95 (2007).</li></ol>

الإعلان عن أي تضارب في المصالح.

ويتعرض نظام الضغط بنجاح منشورات صمام الشريان الأبهر للضغوط التي كانت ممثلة دوري للضغط الانبساطي transvalvular. ومع ذلك ، فإنه لم يكن قادرا على محاكاة الضغط الانقباضي transvalvular ، كما انخفض ضغط فقط إلى 40 مم زئبق. الضغط Transvalvular هو الفرق بين الضغط في الأبهر الصاعد والبطين الأيسر. ?...

<table border="1" style=";text-align:right;direction:rtl"><tbody><tr><th> اسم كاشف </th><th> شركة </th><th> فهرس العدد </th><th> تعليقات (اختياري) </th></tr><tr><td> DMEM </td><td> سيغما </td><td> D5671 </td><td></td></tr><tr><td> Dulbecco في برنامج تلفزيوني </td><td> سيغما </td><td> D5652 </td><td></td></tr><tr><td> Anti-mycotic/antibiotic الحل </td><td> سيغما </td><td> A5955 </td><td></td></tr><tr><td> المصل البقري الجنين </td><td> ThermoScientific </td><td> SH30070 </td><td></td></tr><tr><td> VITON الصمامات غشاء الملف اللولبي </td><td> ماكماستر كار </td><td> 4868K11 </td><td></td></tr><tr><td> محول الضغط </td><td> اوميغا الهندسية ، وشركة </td><td> PX302 - 200GV </td><td></td></tr><tr><td> تحميل خلية مكيف </td><td> الظهور الالكترونيات ، وشركة </td><td> 4025-101 </td><td></td></tr><tr><td> الحصول على البيانات (دق) وحدة </td><td> قياس الحوسبة </td><td> PMD1608 </td><td></td></tr></tbody></table>

design of a cyclic pressure bioreactor for the ex vivo study of aortic heart valves

الصمام الأبهري ، وتقع بين البطين الأيسر والشريان الأورطي ، ويسمح لتدفق الدم أحادي الاتجاه ، ومنع ارتجاعي في البطين. وتتألف منشورات صمام الشريان الأبهر من الخلايا الخلالي علقت داخل المصفوفة خارج الخلية (ECM) وتصطف مع الخلايا البطانية أحادي الطبقة. صمام يقاوم قاسية ، بيئة دينامية ويتعرض باستمرار إلى القص ، والانحناء ، والتوتر والضغط. وقد أظهرت الأبحاث الآفات كلسي في الصمامات المريضة تحدث في مناطق التوتر ميكانيكية عالية نتيجة لتعطل أو البطانية الخلالي مصفوفة الضرر 1-3. وبالتالي ، فإنه ليس من المستغرب أن الدراسات الوبائية أظهرت ارتفاع ضغط الدم ليكون عامل خطر رئيسي في ظهور مرض الصمام الأبهر 4. خيار العلاج الوحيد المتاح حاليا للمرض هو استبدال صمام جراحية لمريضة مع صمام صمام bioprosthetic أو ميكانيكية 5. وتحسين فهم البيولوجيا صمام استجابة للضغوط المادية تساعد في الكشف عن آليات المرضية صمام. في المقابل ، يمكن أن يساعد ذلك في تطوير علاجات غير الغازية مثل التدخل الصيدلانية أو الوقائية. وقد تم تطويره من قبل العديد من المفاعلات الحيوية لدراسة mechanobiology من صمامات القلب الأصلي أو هندسيا 6-9. كما تم تطوير المفاعلات الحيوية نابض لدراسة مجموعة من الأنسجة بما في ذلك الغضروف 10 ، 11 العظام والمثانة 12. كان الهدف من هذا العمل لوضع نظام دوري الضغط التي يمكن استخدامها لتوضيح الاستجابة البيولوجية منشورات صمام الشريان الأبهر للأحمال زيادة الضغط. يتألف النظام من غرفة الاكريليك التي ترغب في وضع العينات وانتاج ضغط الدوري ، والصمامات اللولبي VITON الحجاب الحاجز للسيطرة على توقيت دورة الضغط وجهاز كمبيوتر للتحكم في الأجهزة الكهربائية. تم رصد الضغط باستخدام محول الضغط ، وكانت مشروطة الإشارة باستخدام مكيفات تحميل الخلية. برنامج ابفيو (LabVIEW) ينظم الضغط باستخدام جهاز تمثيلي على ضخ الهواء المضغوط في النظام بسعر مناسب. تحاكي النظام الحيوي مستويات ضغط transvalvular المرتبطة صمام الشريان الأبهر ، وشهدت موجة الأسنان تنتج زيادة تدريجية في الضغط ، نموذجية من التدرج الضغط transvalvular التي موجود في جميع أنحاء صمام أثناء انبساط ، تليها انخفاض ضغط حاد في تصور فتح صمام انقباضة. يسمح البرنامج للمستخدمين ابفيو (LabVIEW) للتحكم في حجم وتواتر الضغط بصفة دورية. كان النظام قادرا على إخضاع عينات الأنسجة لظروف الضغط والفيزيولوجية المرضية. ويمكن استخدام هذا الجهاز لزيادة فهمنا لكيفية صمامات القلب الاستجابة للتغيرات في البيئة المحلية الميكانيكية.

Watch this Scientific Journal Video about Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves at JoVE.com

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

وقد تم تصميم مفاعل حيوي قادر على الضغط دوري تعريض أنسجة القلب صمام ضغط الظروف الفسيولوجية والمرضية. برنامج يتيح للمستخدمين ابفيو (LabVIEW) للسيطرة على ضغط حجم والسعة والتردد. ويمكن استخدام هذا الجهاز لدراسة mechanobiology من نسيج صمام القلب او خلايا معزولة.

تصميم مفاعل حيوي لضغط الدوري السابقين فيفو دراسة صمامات القلب الأورطي

The aortic valve, located between the left ventricle and the aorta, allows for unidirectional blood flow, preventing backflow into the ventricle. Aortic ...

design-cyclic-pressure-bioreactor-for-ex-vivo-study-aortic-heart

Research

Education

JoVE Core

JoVE Journal

Physics

Bioengineering

Unit 1

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

Sources of Magnetic Fields

SCIENTISTS IN ACTION

15.6K Views.  Mississippi State University. وقد تم تصميم مفاعل حيوي قادر على الضغط دوري تعريض أنسجة القلب صمام ضغط الظروف الفسيولوجية والمرضية. برنامج يتيح للمستخدمين ابفيو (LabVIEW) للسيطرة على ضغط حجم والسعة والتردد. ويمكن استخدام هذا الجهاز لدراسة mechanobiology من نسيج صمام القلب او خلايا معزولة.

Video: Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

Patient-specific Modeling of the Heart: Estimation of Ventricular Fiber Orientations

Patient-specific simulations of heart (dys)function aimed at personalizing cardiac therapy are hampered by the absence of in vivo imaging technology for clinically acquiring myocardial fiber orientations. The objective of this project was to develop a methodology to estimate cardiac fiber orientations from in vivo images of patient heart geometries. An accurate representation of ventricular geometry and fiber orientations was reconstructed, respectively, from high-resolution ex vivo structural magnetic resonance (MR) and diffusion tensor (DT) MR images of a normal human heart, referred to as the atlas. Ventricular geometry of a patient heart was extracted, via semiautomatic segmentation, from an in vivo computed tomography (CT) image. Using image transformation algorithms, the atlas ventricular geometry was deformed to match that of the patient. Finally, the deformation field was applied to the atlas fiber orientations to obtain an estimate of patient fiber orientations. The accuracy of the fiber estimates was assessed using six normal and three failing canine hearts. The mean absolute difference between inclination angles of acquired and estimated fiber orientations was 15.4 &deg;. Computational simulations of ventricular activation maps and pseudo-ECGs in sinus rhythm and ventricular tachycardia indicated that there are no significant differences between estimated and acquired fiber orientations at a clinically observable level.The new insights obtained from the project will pave the way for the development of patient-specific models of the heart that can aid physicians in personalized diagnosis and decisions regarding electrophysiological interventions.

A methodology to estimate ventricular fiber orientations from in vivo images of patient heart geometries for personalized modeling is described. Validation of the methodology performed using normal and failing canine hearts demonstrate that that there are no significant differences between estimated and acquired fiber orientations at a clinically observable level.

المريض محددة النمذجة من القلب: تقدير توجهات الألياف البطيني

Patient-specific  simulations of heart (dys)function aimed at personalizing cardiac therapy are hampered  by the absence of in vivo imaging technology for ...

Design of a Biaxial Mechanical Loading Bioreactor for Tissue Engineering

We designed a loading device that is capable of applying uniaxial or biaxial mechanical strain to a tissue engineered biocomposites fabricated for transplantation. While the device primarily functions as a bioreactor that mimics the native mechanical strains, it is also outfitted with a load cell for providing force feedback or mechanical testing of the constructs. The device subjects engineered cartilage constructs to biaxial mechanical loading with great precision of loading dose (amplitude and frequency) and is compact enough to fit inside a standard tissue culture incubator. It loads samples directly in a tissue culture plate, and multiple plate sizes are compatible with the system. The device has been designed using components manufactured for precision-guided laser applications. Bi-axial loading is accomplished by two orthogonal stages. The stages have a 50 mm travel range and are driven independently by stepper motor actuators, controlled by a closed-loop stepper motor driver that features micro-stepping capabilities, enabling step sizes of less than 50 nm. A polysulfone loading platen is coupled to the bi-axial moving platform. Movements of the stages are controlled by Thor-labs Advanced Positioning Technology (APT) software. The stepper motor driver is used with the software to adjust load parameters of frequency and amplitude of both shear and compression independently and simultaneously. Positional feedback is provided by linear optical encoders that have a bidirectional repeatability of 0.1 &mu;m and a resolution of 20 nm, translating to a positional accuracy of less than 3 &mu;m over the full 50 mm of travel. These encoders provide the necessary position feedback to the drive electronics to ensure true nanopositioning capabilities. In order to provide the force feedback to detect contact and evaluate loading responses, a precision miniature load cell is positioned between the loading platen and the moving platform. The load cell has high accuracies of 0.15% to 0.25% full scale.

We designed a novel mechanical loading bioreactor that can apply uniaxial or biaxial mechanical strain to a cartilage biocomposite prior to transplantation into an articular cartilage defect.

تصميم مفاعل حيوي ذو محورين الميكانيكية جار للهندسة الأنسجة

We  designed a loading device that is capable of applying uniaxial or biaxial  mechanical strain to a tissue engineered biocomposites fabricated for  ...

Operation of a Benchtop Bioreactor

Fermentation systems are used to provide an optimal growth environment for many different types of cell cultures. The ability afforded by fermentors to carefully control temperature, pH, and dissolved oxygen concentrations in particular makes them essential to efficient large scale growth and expression of fermentation products. This video will briefly describe the advantages of the fermentor over the shake flask. It will also identify key components of a typical benchtop fermentation system and give basic instruction on setup of the vessel and calibration of its probes. The viewer will be familiarized with the sterilization process and shown how to inoculate the growth medium in the vessel with culture. Basic concepts of operation, sampling, and harvesting will also be demonstrated. Simple data analysis and system cleanup will also be discussed.

Fermentors are used to increase culture yield and productivity of bioengineered cells. After screening multiple microbial or animal cell culture candidates in shake flasks, the next logical step is to increase the selected culture&#x2019;s biomass with the fermentor. This video demonstrates the setup and operation of a typical benchtop bioreactor system.

تشغيل الفوق تفاعلات الاحيائية

Fermentation systems are used to provide an optimal growth environment for many different types of cell cultures. The ability afforded by fermentors to ...

Characterization of Complex Systems Using the Design of Experiments Approach: Transient Protein Expression in Tobacco as a Case Study

Plants provide multiple benefits for the production of biopharmaceuticals including low costs, scalability, and safety. Transient expression offers the additional advantage of short development and production times, but expression levels can vary significantly between batches thus giving rise to regulatory concerns in the context of good manufacturing practice. We used a design of experiments (DoE) approach to determine the impact of major factors such as regulatory elements in the expression construct, plant growth and development parameters, and the incubation conditions during expression, on the variability of expression between batches. We tested plants expressing a model anti-HIV monoclonal antibody (2G12) and a fluorescent marker protein (DsRed). We discuss the rationale for selecting certain properties of the model and identify its potential limitations. The general approach can easily be transferred to other problems because the principles of the model are broadly applicable: knowledge-based parameter selection, complexity reduction by splitting the initial problem into smaller modules, software-guided setup of optimal experiment combinations and step-wise design augmentation. Therefore, the methodology is not only useful for characterizing protein expression in plants but also for the investigation of other complex systems lacking a mechanistic description. The predictive equations describing the interconnectivity between parameters can be used to establish mechanistic models for other complex systems.

We describe a design of experiments approach that can be used to determine and model the influence of transgene regulatory elements, plant growth and development parameters, and incubation conditions on the transient expression of monoclonal antibodies and reporter proteins in plants.

توصيف النظم المعقدة باستخدام تصميم التجارب النهج: عابر التعبير البروتين في التبغ كدراسة حالة

Plants provide multiple benefits for the production of biopharmaceuticals including low costs, scalability, and safety. Transient expression offers the ...

Anatomically Realistic Neonatal Heart Model for Use in Neonatal Patient Simulators

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

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

نموذج القلب الولدان تشريحيا واقعية لاستخدامها في أجهزة محاكاة المرضى حديثي الولادة

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

Light-sheet Fluorescence Microscopy for the Study of the Murine Heart

Light-sheet fluorescence microscopy has been widely used for rapid image acquisition with a high axial resolution from micrometer to millimeter scale. Traditional light-sheet techniques involve the use of a single illumination beam directed orthogonally at sample tissue. Images of large samples that are produced using a single illumination beam contain stripes or artifacts and suffer from a reduced resolution due to the scattering and absorption of light by the tissue. This study uses a dual-sided illumination beam and a simplified CLARITY optical clearing technique for the murine heart. These techniques allow for deeper imaging by removing lipids from the heart and produce a large field of imaging, greater than 10 x 10 x 10 mm3. As a result, this strategy enables us to quantify the ventricular dimensions, track the cardiac lineage, and localize the spatial distribution of cardiac-specific proteins and ion-channels from the post-natal to adult mouse hearts with sufficient contrast and resolution.

This study uses a dual-sided illumination light-sheet fluorescence microscopy (LSFM) technique combined with optical clearing to study the murine heart.

ورقة الضوء الفلورية الفحص المجهري لدراسة قلب مورين

Light-sheet fluorescence microscopy has been widely used for rapid image acquisition with a high axial resolution from micrometer to millimeter scale. ...

A New Ex Vivo Model for the Evaluation of Endoscopic Submucosal Injection Material Performance

Increasing the performance of submucosal injection materials (SIMs) is important for endoscopic therapy of early gastrointestinal cancer. It is essential to establish an ex vivo model that can evaluate SIM performance accurately, for developing high-performance SIMs. In our previous study, we developed a new ex vivo model that can be used to evaluate the performance of various SIMs in detail by applying constant tension to the specimen&#39;s ends. We also confirmed that the proposed new ex vivo model allows accurate submucosal elevation height (SEH) measurement under uniform conditions and detailed comparisons of the performances of various types of SIMs. Here, we describe the new ex vivo model and explain the detailed setup methodology of this model. Since all parts of the new model were easy to obtain, the setup of the new model could be completed quickly. SEH of various SIMs could be measured more accurately by using the new model. The critical factor that determines SIM performance can be identified using the new model. SIM development speed will drastically increase after the factor has been identified.

A New Ex Vivo Model for the Evaluation of Endoscopic Submucosal Injection Material Performance

We developed a new ex vivo model that applies constant tension to the porcine gastric specimen. This development made it possible to evaluate the performance (the height and duration of the submucosal elevation) of various SIMs accurately.&#160; The detailed setup methodology of this new model is explained.

نموذج السابقين فيفو جديد لتقييم أداء مواد الحقن بالمنظار سوبموكوسال

Increasing the performance of submucosal injection materials (SIMs) is important for endoscopic therapy of early gastrointestinal cancer. It is essential ...

Biaxial Mechanical Characterizations of Atrioventricular Heart Valves

Extensive biaxial mechanical testing of the atrioventricular heart valve leaflets can be utilized to derive&#160;optimal parameters used in constitutive models, which provide a mathematical representation of the mechanical function of those structures. This presented biaxial mechanical testing protocol involves (i) tissue acquisition, (ii) the preparation of tissue specimens, (iii) biaxial mechanical testing, and (iv) postprocessing of the acquired data. First, tissue acquisition requires obtaining porcine or ovine hearts from a local Food and Drug Administration-approved abattoir for later dissection to retrieve the valve leaflets. Second, tissue preparation requires using tissue specimen cutters on the leaflet tissue to extract a clear zone for testing. Third, biaxial mechanical testing of the leaflet specimen requires the use of a commercial biaxial mechanical tester, which consists of force-controlled, displacement-controlled, and stress-relaxation testing protocols to characterize the leaflet tissue&#39;s mechanical properties. Finally, post-processing requires the use of data image correlation techniques and force and displacement readings to summarize the tissue&#39;s mechanical behaviors in response to external loading. In general, results from biaxial testing demonstrate that the leaflet tissues yield a nonlinear, anisotropic mechanical response. The presented biaxial testing procedure is advantageous to other methods since the method presented here allows for a more comprehensive characterization of the valve leaflet tissue under one unified testing scheme, as opposed to separate testing protocols on different tissue specimens. The proposed testing method has its limitations in that shear stress is potentially present in the tissue sample. However, any potential shear is presumed negligible.

This protocol involves characterizations of atrioventricular valve leaflets with force-controlled, displacement-controlled, and stress-relaxation biaxial mechanical testing procedures. Results acquired with this protocol can be used for constitutive model development to simulate the mechanical behavior of functioning valves under a finite element simulation framework.

بياكسيال الخصائص الميكانيكية لصمامات القلب بي

Extensive biaxial mechanical testing of the atrioventricular heart valve leaflets can be utilized to derive&#160;optimal parameters used in constitutive ...

A Friction Testing-Bioreactor Device for Study of Synovial Joint Biomechanics, Mechanobiology, and Physical Regulation

In primary osteoarthritis (OA), normal 'wear and tear' associated with aging inhibits the ability of cartilage to sustain its load-bearing and lubrication functions, fostering a deleterious physical environment. The frictional interactions of articular cartilage and synovium may influence joint homeostasis through tissue level wear and cellular mechanotransduction. To study these mechanical and mechanobiological processes, a device capable of replicating the motion of the joint is described. The friction testing device controls the delivery of reciprocal translating motion and normal load to two contacting biological counterfaces. This study adopts a synovium-on-cartilage configuration, and friction coefficient measurements are presented for tests performed in a phosphate-buffered saline (PBS) or synovial fluid (SF) bath. The testing was performed for a range of contact stresses, highlighting the lubricating properties of SF under high loads. This friction testing device can be used as a biomimetic bioreactor for studying the physical regulation of living joint tissues in response to applied physiologic loading associated with diarthrodial joint articulation.

The present protocol describes a friction testing device that applies simultaneous reciprocal sliding and normal load to two contacting biological counterfaces.

جهاز اختبار الاحتكاك - المفاعل الحيوي لدراسة الميكانيكا الحيوية للمفصل الزليلي ، وعلم الأحياء الميكانيكي ، والتنظيم الفيزيائي

In primary osteoarthritis (OA), normal 'wear and tear' associated with aging inhibits the ability of cartilage to sustain its load-bearing and lubrication ...

Procurement and Decellularization of Rat Hindlimbs Using an Ex Vivo Perfusion-Based Bioreactor for Vascularized Composite Allotransplantation

Patients with severe traumatic injuries and tissue loss require complex surgical reconstruction. Vascularized composite allotransplantation (VCA) is an evolving reconstructive avenue for transferring multiple tissues as a composite subunit. Despite the promising nature of VCA, the long-term immunosuppressive requirements are a significant limitation due to the increased risk of malignancies, end-organ toxicity, and opportunistic infections. Tissue engineering of acellular composite scaffolds is a potential alternative in reducing the need for immunosuppression. Herein, the procurement of a rat hindlimb and its subsequent decellularization using sodium dodecyl sulfate (SDS) is described. The procurement strategy presented is based upon the common femoral artery. A machine perfusion-based bioreactor system was constructed and used for ex vivo decellularization of the hindlimb. Successful perfusion decellularization was performed, resulting in a white translucent-like appearance of the hindlimb. An intact, perfusable, vascular network throughout the hindlimb was observed. Histological analyses showed the removal of nuclear contents and the preservation of tissue architecture across all tissue compartments.

Procurement and Decellularization of Rat Hindlimbs Using an Ex Vivo Perfusion-Based Bioreactor for Vascularized Composite Allotransplantation

We describe the surgical technique and decellularization process for composite rat hindlimbs. Decellularization is conducted using low-concentration sodium dodecyl sulfate through an ex vivo machine perfusion system.

شراء وإزالة الخلايا من الأطراف الخلفية للفئران باستخدام مفاعل حيوي قائم على التروية خارج الجسم الحي لزراعة الخيول المركبة الوعائية

Patients with severe traumatic injuries and tissue loss require complex surgical reconstruction. Vascularized composite allotransplantation (VCA) is an ...