We would like to thank the Division of Engineering, Mayo Clinic for their technical support. This study was financially supported by European Regional Development Fund - FNUSA-ICRC (No. CZ.1.05/1.100/02.0123), National Institutes of Health (T32 HL007111), American Heart Association Scientist Development Grant (AHA #06-35185N), and The Grainger Innovation Fund - Grainger Foundation.

Mandrel Collector Poliüretan 1. Elektrospinning <ol><li> Elektrospinning için mandrel hazırlanması <ol><li> dereceli bir silindir içinde biyolojik olarak uyumlu, gıda için suda çözünür taşıyıcı malzeme yaklaşık 8 ml eriyik (yaklaşık 9 mm çapında ve 110 mm derinlik) bir fırın kullanılarak 155 ° C &#39;de. </li><li> mandrel yüzeyi üzerinde destek maddesinin bir kaplama elde etmek için, 3 mm bir çapa ve 100 mm uzunlukta paslanmaz çelik mandrel batırın. daldırma öncesinde erimiş destek malzemesi ile bir yüzey ıslatma yardımcı mandrel yüzeyi sıcaklığını yükseltmek için yaklaşık 15 dakika boyunca 155 ° C&#39;de bir fırında mandrelleri yerleştirin. </li><li> Erimiş destek malzemesi mandreli yüzeyi üzerinde üniform bir ince bir kaplama oluşturan katılaşırken daldırma mili yaklaşık olarak 140 ° C&#39;ye soğumaya bırakılmıştır. yerçekimi kapalı damla fazla destek materyali neden böylece soğutma işlemi sırasında, dikey mili asmak. Bu kaplama kolay sağlarmandrel bitmiş stent greft çıkarılması. </li></ol></li><li> Elektro sisteminin göbek kolektörünün Ayar (Şekil 1 &#39;de gösterildiği gibi) <ol><li> Yatay laboratuvar mikser hizalayın ve davlumbaz içine ters sonunda paslanmaz çelik mandrel yapacak bir plastik çubuk bağlayın. </li><li> mandrel sonunda plastik destek çubuğunu karşılamak için su içinde mandrelin sadece ucu daldırarak mandrelin ucu destek malzemesinin çözülür. Mandrel toplayıcı düzgün dönmesi yardımcı mandrel serbest ucunda plastik destek çubuğunu destekler. </li><li> paslanmaz çelik mandrel güvence altına almak ve elektrospinning esnasında kaymasını önlemek için plastik destek çubuklarının set vidaları kullanın. </li><li> Paslanmaz çelik mandrel bir U-şekilli bir topraklama kablosu takarak göbek toplayıcı Şasiye. malafa kenarlarına topraklama kablosu tutmak için lastik O-halkalarını kullanın. </li></ol></li><li> settiElektrospinning sisteminin sıvı poliüretan ekstrüzyon sistemi ng <ol><li> % 15 elde etmek üzere% 25 (kütle / hacim), poliüretan (PU) stok çözeltisi ile dimetilasetamid (DMA) karışımı (a / h) poliüretan DMA çözeltisi (örneğin, 9 ml% 25 poliüretan çözeltisine DMA 6 ml ilave). DİKKAT! Uygun kişisel koruyucu ekipman ile bir davlumbaz içine çalışın. </li><li> % 15 poliüretan çözeltisi ile kör uç paslanmaz çelik iğne (püskürtme memesi) ile 5 ml&#39;lik bir cam şırınga doldurun. </li><li> şırınganın iç çapına göre 0,01 mL / dakika a&#39;ya şırınga pompası Program. </li><li> yatay yaklaşık 20 cm mandrel kolektörü iğne ucu ile şırınga pompası püskürtme memesinin ile şırınga monte edin. elektrik arkı önlemek için kauçuk sayfaları kullanarak pompa şırınga iletken parçalarından şırınga izole. </li><li> bir timsah klibi kullanarak şırınga püskürtme memesinin yüksek voltaj jeneratörü bağlayın. </li></ol></li><li> 0.01 ml / dak ve rota şırınga pompasını çalıştırırLaboratuvar karıştırıcı yavaş hızda (örneğin, 50 rpm) çalışan mandrel te. </li><li> 20 püskürtme memesinden üzerinden kV ve kolektör mandrel bir gerilim farkı uygulayın. PU nanolifler dönen mandrel üzerine yatırılması başlayacak ve ince bir tabaka birkaç dakika içinde görünür olacaktır. davlumbaz kapatılır ve egzoz electrospun nanoliflerden kaybını önlemek için kapalı olduğundan emin olun. </li></ol> 2. Stent greft elektrospinning <ol><li> (Aşama 1 &#39;de açıklandığı gibi), 2 saat için bir döner mandrel üzerine Electrospin PU nanolifler muntazam bir tüp oluşturmak için kullanılır. </li><li> çıplak metal stent yüklemek için laboratuvar mikser bağlı plastik çubuk mili çıkarın. önce çözücü buharlar kaldırılır kalıntısını sağlamak için mili çıkarmadan davlumbaz ve açık egzoz açın. </li><li> Istenilen konuma electrospun tüpüne balon genişletilebilir paslanmaz çelik stenti 26 kaydırın. o sli yüzden biraz stent genişletmek için gerekli olabilirelectrospun tüp zarar vermeden üzerinde ps. </li><li> Stent sıkıca mandrel üzerine tüp malzeme üzerine kurmak ve slayt yeterince gevşek olmadığından emin olmak için stent kıvırın. Bu, aynı zamanda, iç ve dış tabakaların delaminasyonunu önler ve yardımcı olacaktır. </li><li> Stent-greft dış katmanını elektrospinning için laboratuvar mikser plastik çubuk üzerinde tekrar tüp ve stent ile mandrel yükleyin. </li><li> Aşama 1 &#39;de açıklandığı gibi 3 saat Electrospin nanolifler stent greft dış tabaka imal etmek için. </li><li> Daha sonra dış elektrospinning sonra, çevresel PU malzemeye bir neşter kullanılarak stentin ucundan yaklaşık 1 mm kesti. </li><li> mandrelden stent greft yayınlayacak mandrel destek materyali çözmek için deiyonize su içinde stent-greft mandrel ıslatın. Tamamen destek materyali çözmek için gereken taze su ile değiştirin. </li><li> destek malzemesi çözülür sonra, yavaşça t stent-greft kaldırmako mandrel ve kurumaya bırakın. kuru hava izin vermeden önce geri kalan destek malzemesinin çözünmesi için deiyonize su içinde ayrılmıştır stent greft ıslatma göz önünde bulundurun. </li></ol> İmal Stent-greft 3. Test <ol><li> 3 mm üç katlı balon stent-greft kaydırın. </li><li> aracı sıkma bir el kullanarak balon üzerine stent-greft kıvırın. </li><li> homojen kıvırma nedeniyle stent deformasyona kaplama malzemesi delaminasyonu veya delinme gibi yetmezliği başka işareti için bir mikroskop kullanılarak kıvrılmış stent greft kontrol edin. </li><li> enflasyon cihazı ve su ile üç katlı balon basınç ile 3 mm tasarlanmış çapa stent-greft genişletin. Yine üniforma genişleme ve yetersizliği belirtileri için genişletilmiş stent greft inceleyin. </li></ol>

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Yazarlar hiçbir rakip mali çıkarları olduğunu beyan ederim.

We have developed a fabrication technique for a small caliber stent-graft which can be deployed using a standard percutaneous coronary intervention (PCI) procedure. Stent-grafts currently available are limited in their ability to maintain a low profile and flexibility for deployment. Bare metal stents developed by our group in our previous studies have proven to assist in rapid healing of the stented artery24,26. Various polymers have been electrospun by other groups and polyurethane has been proven biostable ...

Koroner girişim prosedürleri nedeniyle plak ve damar duvarının bozulması önemli damar duvarında yaralanmaya neden olabilir. Bu koroner lümeni 1-4 restenoz, damar greft periferik emboli ve devamsızlık sonuçlanır. Bu komplikasyonlardan kaçınmak için, gelecek vaat eden bir strateji potansiyel restenoz inhibe damar lümeninin süreksizlik gelen risklerin azaltılması ve çevresel emboli önleyecektir anjiyoplasti sitesinde, vasküler yüzeyini kapsayacak şekilde olacaktır. Önceki çalışmalar stent greft 5 için olumlu sonuçları ile greft stent çıplak metal stent karşılaştırılmıştır. Araştırmacılar stent kapsayacak şekilde zarları üretmek için birçok malzemeyi kullandık. Bu polietilen tetraftalat (PET), politetrafloroetilen (PTFE), poliüretan (PU), ve silikon ya da kaplı stentlerin 6-9 üretimi için otolog damar dokusu gibi sentetik malzemeler bulunmaktadır. stenti örtmek için kullanılan ideal bir greft materyali olmayan biodegr, tromboya olmalıdıradable ve aşırı çoğalması ve inflamasyon 10 olmadan yerli dokusu ile entegre edilmelidir. stenti kapsayacak şekilde kullanılan greft materyali de stent-greft iyileşmesini teşvik etmelidir. Stent-greftler yaygın aort koarktasyonu, karotid arter sözde anevrizma, arteriyovenöz fistül tedavisinde kullanılan, greft, ven dejenere ve dev serebral anevrizma büyük. Ama küçük kalibreli stent greft geliştirme stent greft 11-14 dağıtım yardımcıları düşük profilli ve esneklik sağlamak için yeteneği ile sınırlıdır. PU düşük bir profil ve iyi esneklik 15,16 ulaşmak için istenen bir özelliktir iyi mekanik dayanıklılık ile bir elastomerik polimerdir. İyi dağıtılabilirlik sahip olmanın yanı sıra, stent greftler de hızlı iyileşme ve endothelialization teşvik etmelidir. PU stent greftler daha iyi biyouyumluluk gösterdi ve endothelialization 17 arttırmıştır kaplı. araştırmacılar varDaha önce PU endotel hücreleri 17 ile ekim stent-greft kaplı endoteliyalize çalıştı. Nanolif matris oluşturmak için PU elektro damar üretimi 18,19 greft için değerli bir teknik olduğu gösterilmiştir. Doğal hücre-dışı matrisi mimarisini taklit nano varlığı da endotelyal hücre proliferasyonunu 20,21 teşvik ettiği bilinir. Elektrospinning aynı zamanda malzemenin 22 kalınlığı üzerinde kontrol sağlar. PU yapılmış küçük kalibreli damar greft gibi yüzey kaplamaları, antikoagülanlardan ve hücre çoğalması bastırıcı olarak modifikasyonları kullanılarak iyileşmesini sağlamak için çalışılmıştır. Tüm bu değişiklikler konak kabul aracılık ve greft iyileşmesini 23 teşvik için tasarlanmıştır. Grubumuz hayvan modellerinde 24-26 dağıtılabilir bir balon genişletilebilir çıplak metal stent geliştirdi. Bir electrospun poliüretan örgü ve bir top kombinasyonuotuşuna genişleyen stent küçük kalibreli balon genişleyen stent greft oluşturmak için bize sağlamıştır. Mevcut stent greft çoğu girişimsel işlem sırasında femoral arter yoluyla tanıtıldı, ancak sadece bir kaç ticari kapalı stentler bir un-şişirilmiş balon 27 için gerekli olandan daha büyük 1 Fransız boyutu sokulabilir. Bu çalışmada, perkütan girişimsel prosedürde bir standart 8-9 Fransız kılavuz kateter kullanılarak koroner arter teslim edilebilir electrospun PU iki kat arasında bir balon genişletilebilir stent kapsülleme tarafından küçük kalibreli damar stent greft geliştirdik.

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			<td height="21" style="height:21px;width:240px;">Glass syringe</td>
			<td style="width:155px;">Air Tite</td>
			<td style="width:135px;">7.140-33</td>
			<td style="width:457px;">Syringe for spinneret</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:240px;">Graduated cylinder 5 mL</td>
			<td style="width:155px;">Fisher Scientific</td>
			<td style="width:135px;">08-552-4G</td>
			<td>5 mL pyrex graduated cylinder about 9mm diameter and 11 cm long</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:240px;">High voltage generator</td>
			<td style="width:155px;">Bertan Accociates, Inc.</td>
			<td style="width:135px;">205A-30P</td>
			<td>Used to apply voltage difference across spinneret and collector</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:240px;">Laboratory mixer with rpm control</td>
			<td style="width:155px;">Scilogex</td>
			<td style="width:135px;">SCI-84010201</td>
			<td>Available from various laboratory equipment suppliers</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:240px;">Polyurethane</td>
			<td style="width:155px;">DSM</td>
			<td style="width:135px;">BioSpan SPU</td>
			<td>Biospan Segmented Polyurethane</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:240px;">Rubber sheet</td>
			<td style="width:155px;">McMaster Carr</td>
			<td style="width:135px;">1370N11</td>
			<td>Used to insulate syringe during electrospinning</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:240px;">Stainless steel mandrel</td>
			<td style="width:155px;">N/A</td>
			<td style="width:135px;">N/A</td>
			<td>Manufactured&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:240px;">Stainless steel needle</td>
			<td style="width:155px;">Hamilton</td>
			<td style="width:135px;">91018</td>
			<td>Used as spinneret in electrospinning</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:240px;">Support material</td>
			<td style="width:155px;">EnvisionTec</td>
			<td style="width:135px;">B04-HT-DEMOMAT</td>
			<td>Biocompatible water soluble material</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:240px;">Syringe Pump</td>
			<td style="width:155px;">Harvard Apparatus</td>
			<td style="width:135px;">55-3333</td>
			<td></td>
		</tr>
	</tbody>
</table>

fabrication of small caliber stent-grafts using electrospinning and balloon expandable bare metal stents

Stent-grafts are widely used for the treatment of various conditions such as aortic lesions, aneurysms, emboli due to coronary intervention procedures and perforations in vasculature. Such stent-grafts are manufactured by covering a stent with a polymer membrane. An ideal stent-graft should have a biocompatible stent covered by a porous, thromboresistant, and biocompatible polymer membrane which mimics the extracellular matrix thereby promoting injury site healing. The goal of this protocol is to manufacture a small caliber stent-graft by encapsulating a balloon expandable stent within two layers of electrospun polyurethane nanofibers. Electrospinning of polyurethane has been shown to assist in healing by mimicking native extracellular matrix, thereby promoting endothelialization. Electrospinning polyurethane nanofibers on a slowly rotating mandrel enabled us to precisely control the thickness of the nanofibrous membrane, which is essential to achieve a small caliber balloon expandable stent-graft. Mechanical validation by crimping and expansion of the stent-graft has shown that the nanofibrous polyurethane membrane is sufficiently flexible to crimp and expand while staying patent without showing any signs of tearing or delamination. Furthermore, stent-grafts fabricated using the methods described here are capable of being implanted using a coronary intervention procedure using standard size guide catheters.

<html> Bizim electrospinner kurulumu (Şekil 1) yüksek kaliteli poliüretan nanolifler (Şekil 2) sonuçlandı. Bir stent-graft (Şekil 3), bir mandrel üzerine poliüretan bir iç tabaka electrospinning Bu katı üzerine çıplak metal stent kaymasını ve poliüretan bir ikinci dış tabaka Elektrospinning tarafından üretilmiştir. Poliüretan nanolifler 100 um arasında bir iç tabaka ve stent greft 150 um&#39;lik bir dış tabaka ile sonuçlanan 50 um / saat hız?...

Watch this Scientific Journal Video about Fabrication of Small Caliber Stent-grafts Using Electrospinning and Balloon Expandable Bare Metal Stents at JoVE.com

Fabrication of Small Caliber Stent-grafts Using Electrospinning and Balloon Expandable Bare Metal Stents

In the protocol, we present a method to manufacture a small caliber stent-graft by sandwiching a balloon expandable stent between two electrospun nanofibrous polyurethane layers.

Elektrospinning ve Balon Genişletilebilir Bare Metal stentler Kullanma Küçük Caliber Stent-greft Fabrikasyon

Stent-grafts are widely used for the treatment of various conditions such as aortic lesions, aneurysms, emboli due to coronary intervention procedures and ...

fabrication-small-caliber-stent-grafts-using-electrospinning-balloon

Research

JoVE Journal

Medicine

8.8K Görüntüleme.  Mayo Clinic. In the protocol, we present a method to manufacture a small caliber stent-graft by sandwiching a balloon expandable stent between two electrospun nanofibrous polyurethane layers.

Video: Fabrication of Small Caliber Stent-grafts Using Electrospinning and Balloon Expandable Bare Metal Stents

Contrast Enhanced Vessel Imaging using MicroCT

Microscopic computed tomography (microCT) offers high-resolution volumetric imaging of the anatomy of living small animals. However, the contrast between different soft tissues and body fluids is inherently poor in micro-CT images 1. Under these circumstances, visualization of blood vessels becomes a nearly impossible task. To overcome this and to improve the visualization of blood vessels exogenous contrast agents can be used. Herein, we present a methodology for visualizing the vascular network in a rodent model. By using a long-acting aqueous colloidal polydisperse iodinated blood-pool contrast agent, eXIA 160XL, we optimized image acquisition parameters and volume-rendering techniques for finding blood vessels in live animals. Our findings suggest that, to achieve a superior contrast between bone and soft tissue from vessel, multiple-frames (at least 5-8/ frames per view), and 360-720 views (for a full 360&deg; rotation) acquisitions were mandatory. We have also demonstrated the use of a two-dimensional transfer function (where voxel color and opacity was assigned in proportion to CT value and gradient magnitude), in visualizing the anatomy and highlighting the structure of interest, the blood vessel network. This promising work lays a foundation for the qualitative and quantitative assessment of anti-angiogenesis preclinical studies using transgenic or xenograft tumor-bearing mice.

Contrast enhanced small animal vessel imaging by microCT is a rapid, cost-effective and high-throughput technique for serial in situ examination for tumor development, for analyzing the network of blood vessels that nourish them, and for following the response of tumors to preclinical therapeutic intervention(s).

Kontrast Geliştirilmiş Gemi Görüntüleme MicroCT kullanarak

Microscopic computed tomography (microCT) offers high-resolution volumetric imaging of the anatomy of living small animals. However, the contrast between ...

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Protocol for Long Duration Whole Body Hyperthermia in Mice

Hyperthermia is a general term used to define the increase in core body temperature above normal. It is often used to describe the increased core body temperature that is observed during fever. The use of hyperthermia as an adjuvant has emerged as a promising procedure for tumor regression in the field of cancer biology. For this purpose, the most important requirement is to have reliable and uniform heating protocols. We have developed a protocol for hyperthermia (whole body) in mice. In this protocol, animals are exposed to cycles of hyperthermia for 90 min followed by a rest period of 15 min. During this period mice have easy access to food and water. High body temperature spikes in the mice during first few hyperthermia exposure cycles are prevented by immobilizing the animal. Additionally, normal saline is administered in first few cycles to minimize the effects of dehydration. This protocol can simulate fever like conditions in mice up to 12-24 hr. We have used 8-12 weeks old BALB/Cj female mice to demonstrate the protocol.

This paper describes a protocol for whole body hyperthermia in mice that can stimulate fever like conditions up to 12-24 hr.

Farelerde Uzun Süre Whole Body Hipertermi için protokol

Hyperthermia is a general term used to define the increase in core body temperature above normal. It is often used to describe the increased core body ...

Vascular Balloon Injury and Intraluminal Administration in Rat Carotid Artery

The carotid artery balloon injury model in rats has been well established for over two decades. It remains an important method to study the molecular and cellular mechanisms involved in vascular smooth muscle dedifferentiation, neointima formation and vascular remodeling. Male Sprague-Dawley rats are the most frequently employed animals for this model. Female rats are not preferred as female hormones are protective against vascular diseases and thus introduce a variation into this procedure. The left carotid is typically injured with the right carotid serving as a negative control. Left carotid injury is caused by the inflated balloon that denudes the endothelium and distends the vessel wall. Following injury, potential therapeutic strategies such as the use of pharmacological compounds and either gene or shRNA transfer can be evaluated. Typically for gene or shRNA transfer, the injured section of the vessel lumen is locally transduced for 30 min with viral particles encoding either a protein or shRNA for delivery and expression in the injured vessel wall. Neointimal thickening representing proliferative vascular smooth muscle cells usually peaks at 2 weeks after injury. Vessels are mostly harvested at this time point for cellular and molecular analysis of cell signaling pathways as well as gene and protein expression. Vessels can also be harvested at earlier time points to determine the onset of expression and/or activation of a specific protein or pathway, depending on the experimental aims intended. Vessels can be characterized and evaluated using histological staining, immunohistochemistry, protein/mRNA assays, and activity assays. The intact right carotid artery from the same animal is an ideal internal control. Injury-induced changes in molecular and cellular parameters can be evaluated by comparing the injured artery to the internal right control artery. Likewise, therapeutic modalities can be evaluated by comparing the injured and treated artery to the control injured only artery.

This protocol uses a balloon catheter to cause an intraluminal injury on the rat carotid artery and henceforth elicit neointimal hyperplasia. This is a well-established model for studying the mechanisms of vascular remodeling in response to injury. It is also widely used to determine the validity of potential therapeutic approaches.

Sıçan Karotis Arter Vasküler Balon Yaralanma ve intraluminal İdaresi

The carotid artery balloon injury model in rats has been well established for over two decades. It remains an important method to study the molecular and ...

A Rat Carotid Balloon Injury Model to Test Anti-vascular Remodeling Therapeutics

The rat carotid balloon injury is a well-established surgical model that has been used to study arterial remodeling and vascular cell proliferation. It is also a valuable model system to test, and to evaluate therapeutics and drugs that negate maladaptive remodeling in the vessel. The injury, or barotrauma, in the vessel lumen caused by an inflated balloon via an inserted catheter induces subsequent neointimal growth, often leading to hyperplasia or thickening of the vessel wall that narrows, or obstructs the lumen. The method described here is sufficiently sensitive, and the results can be obtained in relatively short time (2 weeks after the surgery). The efficacy of the drug or therapeutic against the induced-remodeling can be evaluated either by the post-mortem pathological and histomorphological analysis, or by ultrasound sonography in live animals. In addition, this model system has also been used to determine the therapeutic window or the time course of the administered drug. These studies can leadto the development of a better administrative strategy and a better therapeutic outcome. The procedure described here provides a tool for translational studies that bring drug and therapeutic candidates from bench research to clinical applications.

The rat carotid balloon injury model described below allows researchers to evaluate drugs or therapeutics that negate injury-induced arterial hyperplasia. Detailed pre-surgical preparation, surgical procedure, and post-surgical cares of the animal are described.

Rat Karotis Balon Yaralanma Modeli Anti-vasküler Tadilat Therapeutics Test

The rat carotid balloon injury is a well-established surgical model that has been used to study arterial remodeling and vascular cell proliferation. It is ...

Balloon-based Injury to Induce Myointimal Hyperplasia in the Mouse Abdominal Aorta

The use of animal models is essential for a better understanding of MH, one major cause for arterial stenosis.In this article, we demonstrate a murine balloon denudation model, which is comparable with established vessel injury models in large animals. The aorta denudation model with balloon catheters mimics the clinical setting and leads to comparable pathobiological and physiological changes. Briefly, after performing a horizontal incision in the aorta abdominalis, a balloon catheter will be inserted into the vessel, inflated, and introduced retrogradely. Inflation of the balloon will lead to intima injury and overdistension of the vessel. After removing the catheter, the aortic incision will be closed with single stiches. The model shown in this article is reproducible, easy to perform, and can be established quickly and reliably. It is especially suitable for evaluating expensive experimental therapeutic agents, which can be applied in an economical fashion. By using different knockout-mouse strains, the impact of different genes on MH development can be assessed.

This article demonstrates a murine model to study the development of myointimal hyperplasia (MH) after aortic balloon injury.

Fare Abdominal aort Myointimal Hiperplazi ikna etmek için balon tabanlı yaralanma

The use of animal models is essential for a better understanding of MH, one major cause for arterial stenosis.In this article, we demonstrate a murine ...

In Vivo Evaluation of Fracture Callus Development During Bone Healing in Mice Using an MRI-compatible Osteosynthesis Device for the Mouse Femur

Endochondral fracture healing is a complex process involving the development of fibrous, cartilaginous, and osseous tissue in the fracture callus. The amount of the different tissues in the callus provides important information on the fracture healing progress. Available in vivo techniques to longitudinally monitor the callus tissue development in preclinical fracture-healing studies using small animals include digital radiography and &#181;CT imaging. However, both techniques are only able to distinguish between mineralized and non-mineralized tissue. Consequently, it is impossible to discriminate cartilage from fibrous tissue. In contrast, magnetic resonance imaging (MRI) visualizes anatomical structures based on their water content and might therefore be able to noninvasively identify soft tissue and cartilage in the fracture callus. Here, we report the use of an MRI-compatible external fixator for the mouse femur to allow MRI scans during bone regeneration in mice. The experiments demonstrated that the fixator and a custom-made mounting device allow repetitive MRI scans, thus enabling longitudinal analysis of fracture-callus tissue development.

In Vivo Evaluation of Fracture Callus Development During Bone Healing in Mice Using an MRI-compatible Osteosynthesis Device for the Mouse Femur

The evaluation of tissue development in the fracture callus during endochondral bone healing is essential to monitor the healing process. Here, we report the use of a magnetic resonance imaging (MRI)-compatible external fixator for the mouse femur to allow MRI scans during bone regeneration in mice.

Vivo Fare uyluk için bir MRI uyumlu Osteosentez aygıtı kullanma farelerde kemik iyileşme sırasında kırık Kallus gelişimi değerlendirme

Endochondral fracture healing is a complex process involving the development of fibrous, cartilaginous, and osseous tissue in the fracture callus. The ...

Mechanisms Underlying Gut Hormone Secretion Using the Isolated Perfused Rat Small Intestine

The gut is the largest endocrine organ of the body, producing more than 15 different peptide hormones that regulate appetite and food intake, digestion, nutrient absorption and distribution, and post-prandial glucose excursions. Understanding the molecular mechanisms that regulate gut hormone secretion is fundamental for understanding and translating gut hormone physiology. Traditionally, the mechanisms underlying gut hormone secretion are either studied in vivo (in experimental animals or humans) or using gut hormone-secreting primary mucosal cell cultures or cell lines. Here, we introduce an isolated perfused rat small intestine as an alternative method for studying gut hormone secretion. The virtues of this model are that it relies on the intact gut, meaning that it recapitulates most of the physiologically important parameters responsible for the secretion in in vivo studies, including mucosal polarization, paracrine relationships and routes of perfusion/stimulus exposure. In addition, and unlike in vivo studies, the isolated perfused rat small intestine allows for almost complete experimental control and direct assessment of secretion. In contrast to in vitro studies, it is possible to study both the magnitude and the dynamics of secretion and to address important questions, such as what stimuli cause secretion of different gut hormones, from which side of the gut (luminal or vascular) is secretion stimulated, and to analyze in detail molecular sensors underlying the secretory response. In addition, the preparation is a powerful model for the study of intestinal absorption and details regarding the dynamics of intestinal absorption including the responsible transporters.

Here, we present a powerful and physiological model to study the molecular mechanisms underlying gut hormone secretion and intestinal absorption &#8212; the isolated perfused rat small intestine.

Gut hormonu salgılanması izole kullanarak temel mekanizmaları fare bağırsağı periosteum

The gut is the largest endocrine organ of the body, producing more than 15 different peptide hormones that regulate appetite and food intake, digestion, ...

Implantation of Human-Sized Coronary Stents into Rat Abdominal Aorta Using a Trans-Femoral Access

Percutaneous coronary intervention (PCI), combined with the deployment of a coronary stent, represents the gold standard in interventional treatment of coronary artery disease. In-stent restenosis (ISR) is determined by an excessive proliferation of neointimal tissue within the stent and limits the long-term success of stents. A variety of animal models have been used to elucidate pathophysiological processes underlying in-stent restenosis (ISR), with the porcine coronary and the rabbit iliac artery models being the most frequently used. Murine models provide the advantages of high throughput, ease of handling and housing, reproducibility, and a broad availability of molecular markers. The apolipoprotein E deficient (apoE-/- ) mouse model has been widely used to study cardiovascular diseases. However, stents must be miniaturized to be implanted into mice, involving important changes of their mechanical and (potentially) biological properties. The use of apoE-/- rats can overcome these shortcomings as apoE-/- rats allow for the evaluation of human-sized coronary stents while at the same time providing an atherogenic phenotype. This makes them an excellent and reliable model to investigate ISR after stent implantation. Here, we describe, in detail, the implantation of commercially available human coronary stents into the abdominal aorta of rats with an apoE-/- background using a trans-femoral access.

This protocol describes the implantation of human coronary stents into the abdominal aorta of rats with an apoE-/- background using a trans-femoral access. Compared with other animal models, murine models carry the advantages of high throughput, reproducibility, ease of handling and housing, and a broad availability of molecular markers.

Trans-Femoral Erişim Kullanılarak İnsan Büyüklüğünde Koroner Stentlerin Rat Abdominal Aort'a yerleştirilmesi

Percutaneous coronary intervention (PCI), combined with the deployment of a coronary stent, represents the gold standard in interventional treatment of ...

The Intra-Aortic Balloon Pump

Cardiogenic shock remains one of the most challenging clinical syndromes in modern medicine. Mechanical support is being increasingly used in the management of cardiogenic shock. Intra-aortic balloon pump (IABP) is one of the earliest and most widely used types of mechanical circulatory support. The device acts by external counterpulsation and uses systolic unloading and diastolic augmentation of aortic pressure to improve hemodynamics. Although IABP provides less hemodynamic support when compared with newer mechanical circulatory support devices, it can still be the mechanical support device of choice in appropriate situations because of its relative simplicity of insertion and removal, need for smaller size vascular access and better safety profile. In this review, we discuss the equipment, procedural and technical aspects, hemodynamic effects, indications, evidence, current status and recent advances in the use of IABP in cardiogenic shock.

We describe the steps for the percutaneous implantation of the intra-aortic balloon pump (IABP), a mechanical circulatory support device. It acts by counterpulsation, inflating at the onset of diastole, augmenting diastolic aortic pressure and improving coronary blood flow and systemic perfusion, and deflating before systole, reducing left ventricular afterload.

Aort İçi Balon Pompası

Cardiogenic shock remains one of the most challenging clinical syndromes in modern medicine. Mechanical support is being increasingly used in the ...

Combining 3D-Printing and Electrospinning to Manufacture Biomimetic Heart Valve Leaflets

Electrospinning has become a widely used technique in cardiovascular tissue engineering as it offers the possibility to create (micro-)fibrous scaffolds with adjustable properties. The aim of this study was to create multilayered scaffolds mimicking the architectural fiber characteristics of human heart valve leaflets using conductive 3D-printed collectors.
Models of aortic valve cusps were created using commercial computer-aided design (CAD) software. Conductive polylactic acid was used to fabricate 3D-printed leaflet templates. These cusp negatives were integrated into a specifically designed, rotating electrospinning mandrel. Three layers of polyurethane were spun onto the collector, mimicking the fiber orientation of human heart valves. Surface and fiber structure was assessed with a scanning electron microscope (SEM). The application of fluorescent dye additionally permitted the microscopic visualization of the multilayered fiber structure. Tensile testing was performed to assess the biomechanical properties of the scaffolds.
3D-printing of essential parts for the electrospinning rig was possible in a short time for a low budget. The aortic valve cusps created following this protocol were three-layered, with a fiber diameter of 4.1 &#177; 1.6 &#181;m. SEM imaging revealed an even distribution of fibers. Fluorescence microscopy revealed individual layers with differently aligned fibers, with each layer precisely reaching the desired fiber configuration. The produced scaffolds showed high tensile strength, especially along the direction of alignment. The printing files for the different collectors are available as Supplemental File 1, Supplemental File 2, Supplemental File 3, Supplemental File 4, and Supplemental File 5.
With a highly specialized setup and workflow protocol, it is possible to mimic tissues with complex fiber structures over multiple layers. Spinning directly on 3D-printed collectors creates considerable flexibility in manufacturing 3D shapes at low production costs.

The presented method offers an innovative way for engineering biomimetic fiber structures in three-dimensional (3D) scaffolds (e.g., heart valve leaflets). 3D-printed, conductive geometries were used to determine shape and dimensions. Fiber orientation and characteristics were individually adjustable for each layer. Multiple samples could be manufactured in one setup.

Biyomimetik Kalp Kapağı Broşürleri Üretmek için 3D Baskı ve Elektrospinning'i Birleştirme

Electrospinning has become a widely used technique in cardiovascular tissue engineering as it offers the possibility to create (micro-)fibrous scaffolds ...