We thank the patients for participating in this study. We are also grateful to the Biomedicine Electron Microscopy Laboratory of Basic Medical Science School of Central South University, particularly to Xiaoying Wu and Jin Li for technical support. This work was supported by the National Key Research and Development Program (No. 2018YFC1311204).

The Institutional Review Board approved the study protocol, and samples of the dilated left atrium (LA) tissues in the dextrocardia cases were collected for electron microscopy after written informed consent had been obtained.
1. Surgical procedure and ablation
<ol>
	<li>Perform a median sternotomy and suspend the left lateral pericardium after opening.
	<ol>
		<li>Cannulate the ascending aorta and the superior and inferior vena cava (SVC, IVC) to establish mild hypothermic cardiopulmonary bypass (CPB).</li>
		<li>Have the operator switch position from the right side to the left of the operating table after establishing the bypass.</li>
		<li>Give antegrade cold blood cardioplegia intermittently from the aortic root to achieve cardioplegic arrest.</li>
		<li>Perform the right atrial (RA) incision on the left side of the heart, parallel to the atrioventricular sulcus, providing exposure for subsequent RA ablation and tricuspid valve surgery. Ensure the left-sided left atriotomy is located parallelly under the interatrial groove.</li>
		<li>Place a retractor on the wall of LA for sufficient exposure to perform LA ablation and approach the mitral valve (MV).</li>
		<li>Make an aortic incision via a transverse aortotomy performed specially for selective antegrade cardioplegia into the left and right coronary orifices and subsequent AV surgery. 
		NOTE: This was done for the second patient.</li>
	</ol>
	</li>
	<li>Cryoablation 
	NOTE: In the previous two patients, cryoablation was performed exclusively using a flexible, 10 cm long, metal cryoprobe (see the Table of Materials). The cryoprobe uses nitrous oxide (N2O) gas to achieve rapid atrial tissue freezing to a target of -60 &#176;C10.
	<ol>
		<li>Design the cryolesion set to replicate the mirror image of the CMP-IV lesion set. Set the duration of the LA cryoablation for each lesion at -60 &#176;C for 2 min.
		<ol>
			<li>Ensure the posterior LA box lesion is composed of the LA incision and the cryolesion encircling the left and right pulmonary veins.</li>
			<li>Apply a cryolesion line to connect the left superior pulmonary vein with the left atrial appendage (LAA).</li>
			<li>Form an ice ball to mark the coronary sinus using cryoablation from the epicardium (Figure 2). When performing the mitral isthmus line, place the cryoprobe at the inferior aspect of the left atriotomy and direct it to the mitral annulus at the 8 o&#39;clock position, across the posterior LA and coronary sinus, as marked with the ice ball (Figure 3A).</li>
			<li>Apply right-sided LAA amputation.</li>
			<li>After the LA cryoablation, sample 4 x 8 mm tissue of the cryoablated LA for electron microscopic examination. In addition, sample a similar, large, nonablated tissue from the margin of the LA incision for the control test. 
			NOTE: Nonablated tissue was sampled in the second case.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Perform prosthetic valve replacement surgery with a 27 mm mechanical MV using a 2-0 polypropylene running suture. Replace a 23 mm mechanical AV with 2-0 polypropylene running sutures. 
	NOTE: The mechanical MV replacement surgery was performed on the first patient, whereas the replacement with the mechanical AV was done for the second patient.</li>
	<li>Perform the RA cryoablation during the CPB, with the heart warm and beating, for 2 min at -60 &#176;C for each ablation lesion.
	<ol>
		<li>Create the linear cryoablation lines from the inferior aspect of the left-sided right atriotomy up onto the SVC and down to the IVC (Figure 3B).</li>
		<li>Make the tricuspid isthmus linear cryolesion from the midportion of the right atriotomy, directed endocardially toward the tricuspid annulus at the 10 o&#39;clock position (Figure 3B and Figure 4).</li>
		<li>Make a lateral cryolesion from the midportion of the right atriotomy up to the tip of the right atrial appendage (RAA).</li>
	</ol>
	</li>
	<li>Perform three-dimensional (3D) printing of the heart in advance, using the derived cardiac CT data (Figure 5)11. 
	NOTE: This was done for the third patient.
	<ol>
		<li>Access the left atrium through the interatrial groove during the operation. Extend the mitral isthmus lesion to the posterior mitral annulus for the left atrial lesion sets and ablate the coronary sinus in the endocardium and epicardium with a bipolar radiofrequency pen.
		<ol>
			<li>Make other lesions using bipolar radiofrequency clamps: (i) bilateral pulmonary vein isolation; (ii) ablation lines connecting the left atrial appendage and the left superior pulmonary vein; (iii) ablation lines connecting the right and the left superior pulmonary veins; (iv) ablation lines connecting the right and the left inferior pulmonary veins, and (v) mitral line lesions (Figure 3A).</li>
			<li>Dissect the Marshall ligament, and separate the left atrial appendage using an epicardial atrial clamp closure device. Use bipolar radiofrequency forceps to ablate the entire right atrial lesion sets, including the annular tricuspid valve lesions, superior and inferior vena cava lesion lines, and lesion lines connecting the right atrium incision to the right atrial appendage (Figure 3B).</li>
		</ol>
		</li>
		<li>Resect the A1 ruptured chordae, implant a single, flexible, artificial chord with 4-0 expanded polytetrafluoroethylene in situ (see the Table of Materials), and close the residual leak of the anterior commissure and the A2 leaflet cleft.
		<ol>
			<li>Implant a 32 mm, rigid mitral ring to stabilize the annulus. Ensure that the coaptation height is 9 mm after the mitral valve reconstruction. After de-airing and closure of the interatrial sulcus incision, remove the aortic clamp, then make a longitudinal incision on the surface of the right atrium.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Perform the tricuspid annuloplasty with a 30 mm tricuspid ring or with a 28 mm band, implanting them in an &#34;upside-down&#34; and particularly &#34;mirror-image inversion&#34; manner using 2-0 polyester interrupted sutures (Figure 6). Remove the holder before fixation of the annuloplasty ring. 
	NOTE: Tricuspid annuloplasty was performed in the previous two patients, while the band was used in the third case.</li>
	<li>Ensure that sinus rhythm is restored in all patients without any atrioventricular block before cardiopulmonary bypass weaning. Fix temporary epicardial pacing wires after the cardiac surgery.</li>
</ol>
2. Postoperative management and follow-up
<ol>
	<li>Monitor all patients by continuous ECG recordings during hospitalization to ensure no early AF recurrence occurs.</li>
	<li>Administer antiarrhythmic drugs (AADs) orally, with 200 mg/day of amiodarone routinely, for the first 3-6 months to prevent recurrence of AF.</li>
	<li>Administer warfarin for oral anticoagulation and test prothrombin time (PT) regularly.</li>
	<li>Perform chest roentgenogram, TTE, ECG, and 24 h Holter before discharge.</li>
	<li>After hospital discharge, follow all patients with clinical examination, PT test, TTE, ECG, and 24 h Holter at 3, 6, 12, 18, 24, 36, and 48 months after surgery. 
	NOTE: The third patient was followed during a 12-month follow-up period.</li>
</ol>

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The authors have no conflicts of interest to disclose.

Dextrocardia is a group of rare heart defects in which the heart is situated on the right side of the thoracic cavity instead of on the left side. One-third of all dextrocardia cases are mirror-image cases, which means the orientation of the cardiac chambers is a mirror image to levocardia (normally situated heart)12. It is estimated that situs inversus dextrocardia associated with situs inversus totalis occurs with an incidence of much less than 1 in 10,000-50,000 births1<...

Dextrocardia is a rare, congenital cardiac malformation in which the axis of the heart is indexed to the right side of the thoracic cavity. Dextrocardia with situs inversus totalis refers to all visceral organs, including the heart, being mirrored and is extremely rare1,2. Atrial fibrillation (AF) is the most common arrhythmia that affects millions of people and causes substantial morbidity and mortality, especially with respect to the increased risk of stroke3.
A literature survey was unable to demonstrate a definitive approach for the concomitant Cox-Maze procedure (CMP) and valve surgery in dextrocardia with situs inversus. There are only a few reports of mitral valve replacement in cases of dextrocardia with situs solitus and even less in situs inversus4,5,6,7,8,9. However, those strategies are not applicable to tricuspid valve surgery, not to mention the complex CMP-IV in dextrocardia.
This paper reports the surgical techniques and experience in three cases concerning the biatrial lesion set of the CMP-IV operation using cryoablation or radiofrequency ablation concomitantly with valve surgery in situs inversus dextrocardia. All surgeries succeeded in the maintenance of sinus rhythm (SR) at 12 months follow-up to each patient and at 48 months follow-up to the previous two. Electron microscopy was used to investigate the transmurality of the atrial cryoablation.
CASE PRESENTATION:
Patients and preoperative examination 
From February 2016 to September 2020, a 48-year-old female patient, a 55-year-old male patient, and a 39-year-old male patient were successively admitted to the cardiac center with similar complaints of palpitation, dyspnea, and easy fatigability on exertion lasting for years (Table 1). They all denied any familiar history of situs inversus dextrocardia or other cardiac health comorbidities. All patients were referred to electrocardiography (ECG), chest roentgenography (Figure 1), computed tomography (CT), and Doppler transthoracic echocardiography (TTE) routinely for preoperative examination.
Case 1: A 48-year-old woman presented with complaints of palpitation, dyspnea, and easy fatigability on exertion lasting for years. The anamnesis was unremarkable. During the physical examination, a grade 3 systolic blowing murmur was heard in the fifth intercostal space outside the midline of the right clavicle. X-ray plain film and CT scan showed that the contour of the dextrocardia was enlarged and situs inversus totalis. Transesophageal echocardiography revealed moderate to severe mitral regurgitation and mild tricuspid regurgitation after moderate mitral valve prolapse and tricuspid annular dilation. There was no thrombosis, and the diameter of the left atrium was 5.3 cm. AF with a rapid ventricular rate was detected by ECG.
Case 2: A 55-year-old man presented with similar symptoms for years. There was no history of cardiac health comorbidities; however, he had had a stroke about six months ago. On physical examination, a diastolic blowing murmur was heard at the left second intercostal space, radiating to the neck. Plain X-ray and CT scan revealed dextrocardia with an enlarged contour and situs inversus totalis. Transesophageal echocardiography showed moderate aortic valve regurgitation and mild to moderate tricuspid regurgitation following mild aortic prolapse and tricuspid annular dilation. The diameter of the left atrium was 4.5 cm without atrial thrombosis. AF with a rapid ventricular rate was detected by ECG.
Case 3: A 39-year-old male presented with progressive exertional dyspnea and intermittent palpitation without any history of situs inversus dextrocardia or other cardiac health complications. During the physical examination, a grade 3 systolic blowing murmur was heard in the fifth intercostal space outside the midline of the right clavicle. X-ray plain film and CT scan revealed that the contour of dextrocardia was enlarged and situs inversus totalis. Transesophageal echocardiography showed severe mitral valve regurgitation and tricuspid regurgitation after annular enlargement. There was no atrial thrombosis, and the left atrium diameter was 5.8 cm. A 24 h ambulatory ECG demonstrated paroxysmal AF with a total load of 165 min.
Diagnosis, assessment, and plan 
Case 1: A biatrial cryo-Cox-Maze IV procedure (cryo-CMP-IV) with mechanic mitral valve replacement and tricuspid annuloplasty were simultaneously performed.
Case 2: A biatrial cryo-CMP-IV procedure with concomitant mechanic aortic valve (AV) replacement and tricuspid annuloplasty was performed.
Case 3: A biatrial CMP-IV procedure, mitral valvuloplasty, and tricuspid annuloplasty were performed simultaneously.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>CryoICE</td>
			<td>AtriCure, Cincinnati, Ohio</td>
			<td>CRYO2</td>
			<td>Cryoablation in case 1 and case 2 was performed exclusively using it with a flexible 10cm in length metal cryoprobe.</td>
		</tr>
		<tr>
			<td>Medtronic Open Pivot Standard mechanical MV</td>
			<td>Medtronic, Minneapolis, Minn</td>
			<td>709291 / MHV 500DM27 STD MITRAL</td>
			<td>A 27-mm MV was adopted in case 1.</td>
		</tr>
		<tr>
			<td>Medtronic Open Pivot Standard mechanical AV</td>
			<td>Medtronic, Minneapolis, Minn</td>
			<td>646871 / MHV 500FA23 STD AORTIC</td>
			<td>A 23-mm AV was adopted in case 2.</td>
		</tr>
		<tr>
			<td>bipolar radiofrequency pen</td>
			<td>AtriCure Inc., Cincinnati, OH</td>
			<td></td>
			<td>Maze-IV in case 3</td>
		</tr>
		<tr>
			<td>bipolar radiofrequency clamps</td>
			<td>AtriCure Inc., Cincinnati, OH</td>
			<td></td>
			<td>Maze-IV in case 3</td>
		</tr>
		<tr>
			<td>Goretex</td>
			<td>W.L. Gore &#38; Associates, Inc., Elkton, Maryland</td>
			<td></td>
			<td>A surgical suture made of polytetrafluoroethylene.</td>
		</tr>
		<tr>
			<td>rigid mitral ring</td>
			<td>Kingstron Bio, Suzhou, China</td>
			<td>Element Force ARM32</td>
			<td>A 32 mm ring was adopted in case 3.</td>
		</tr>
		<tr>
			<td>Tricuspid Sovering Band</td>
			<td>Sorin Group Italia S.r.l., VC, Italy</td>
			<td>SBG0730 / SB30T</td>
			<td>A 30 mm ring was adopted in case 1.</td>
		</tr>
		<tr>
			<td>Tricuspid Sovering Band</td>
			<td>Sorin Group Italia S.r.l., VC, Italy</td>
			<td>SQB0240 / SB30T</td>
			<td>A 30 mm ring was adopted in case 2.</td>
		</tr>
		<tr>
			<td>Tricuspid Sovering Band</td>
			<td>Sorin Group Italia S.r.l., VC, Italy</td>
			<td>SBF0930 / SB28T</td>
			<td>A 28 mm band was adopted in case 3.</td>
		</tr>
	</tbody>
</table>

cox-maze iv procedure concomitant with valvular surgery in situs inversus dextrocardia: a single-center experience in china

Atrial fibrillation (AF) is the most common cardiac arrhythmia. The use of ablation technologies made the Cox-Maze IV procedure (CMP-IV) technically easier, faster, becoming the gold standard for the surgical treatment of AF. However, the efficacy and safety of CMP-IV in situs inversus dextrocardia are largely unknown. This paper summarizes the CMP-IV procedure performed concomitantly with valvular surgery in patients with situs inversus dextrocardia at this institution.
From February 2016 to September 2020, three dextrocardia patients with persistent AF and valvular diseases were referred to this institution for valvular and CMP-IV surgery. CMP-IV was performed using either cryoablation with a nitrous oxide (N2O)-based cryoprobe or a bipolar radiofrequency clamp and bipolar radiofrequency pen. Mechanical valve replacement or mitral vavuloplasty was performed in another patient in addition to tricuspid annuloplasty. Transmurality of the ablated atrial tissues was evaluated by electron microscopy. Heart function was assessed by transthoracic echocardiography. Cardiac rhythm was monitored by 24 h Holter at 3, 6, 12, 18, 24, and 48 months follow-up. 
All the AF was successfully eliminated in the ablation procedure without recurrence or other complications during hospitalization. The mean bypass and crossclamp times were similar in all the patients. The postoperative ventilator support time, the duration of stay in the ICU, and postoperative residence time were also not significantly different among the patients. Transmural atrial necrosis was detected in the ablated atrial tissues. Sinus rhythm maintenance was achieved at 3, 6, 12, 18, 24, and 48 months follow-up in all the patients. All valve protheses switched freely; no tricuspid regurgitation was observed. The results of the present study demonstrate that the CMP-IV is safe and effective in eliminating AF in dextrocardia patients concomitant with valvular surgery.

Surgical procedure and early postoperative period 
A mechanic MV replacement, tricuspid annuloplasty, and concomitant cryo-CMP-IV were performed simultaneously for the first patient. The second had undergone surgery of mechanic AV replacement, tricuspid annuloplasty, and concomitant cryo-CMP-IV. In the third patient, a biatrial CMP-IV procedure was performed simultaneously with mitral valvuloplasty and tricuspid annuloplasty. All operations were smooth, and each beating heart restored SR after resus...

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Cox-Maze IV Procedure Concomitant with Valvular Surgery In Situs Inversus Dextrocardia: A Single-Center Experience in China

We summarize the Cox-Maze IV procedure concomitant with valvular surgery performed in patients with situs inversus dextrocardia at this institution.

Atrial fibrillation (AF) is the most common cardiac arrhythmia. The use of ablation technologies made the Cox-Maze IV procedure (CMP-IV) technically ...

cox-maze-iv-procedure-concomitant-with-valvular-surgery-situs

Research

JoVE Journal

Medicine

3.2K Views.  Central South University. We summarize the Cox-Maze IV procedure concomitant with valvular surgery performed in patients with situs inversus dextrocardia at this institution.

Video: Cox-Maze IV Procedure Concomitant with Valvular Surgery In Situs Inversus Dextrocardia: A Single-Center Experience in China

Sequencing of Bacterial Microflora in Peripheral Blood: our Experience with HIV-infected Patients

The healthy gastrointestinal tract is physiologically colonized by a large variety of commensal microbes that influence the development 
	of the humoral and cellular mucosal immune system1,2. 
 Microbiota is shielded from the immune system via a strong mucosal barrier. Infections and antibiotics are known to alter both the normal 
	gastrointestinal tract barrier and the composition of resident bacteria, which may result in possible immune abnormalities3.
HIV causes a breach in the gastrointestinal barrier with progressive failure of mucosal immunity and leakage into the systemic circulation of bacterial bioproducts, such as lipopolysaccharide and 
	bacterial DNA fragments, which contribute to systemic immune activation4-7. Microbial translocation is implicated in HIV/AIDS immunopathogenesis and response to therapy 4,8.
We aimed to characterise the composition of bacteria translocating in peripheral blood of HIV-infected patients. To pursue our aim we set up a PCR reaction for the panbacteric 16S ribosomial gene 
	followed by a sequencing analysis.
Briefly, whole blood from both HIV-infected and healthy subjects is used. Given that healthy individuals present normal intestinal homeostasis no translocation of microflora is expected in 
	these patients. Following whole blood collection by venipuncture and plasma separation, DNA is extracted from plasma and used to perform a broad range PCR reaction for the panbacteric 
	16S ribosomial gene9. Following PCR product purification, cloning and sequencing analyses are performed.

Our experiment will show how to perform a sequencing analysis of bacterial species translocating in peripheral blood of HIV positive patients.

The healthy gastrointestinal tract is physiologically colonized by a large variety of commensal microbes that influence the development 
	of the humoral ...

Improving IV Insulin Administration in a Community Hospital

Diabetes mellitus is a major independent risk factor for increased morbidity and mortality in the hospitalized patient, and elevated blood glucose concentrations, even in non-diabetic patients, predicts poor outcomes.1-4 The 2008 consensus statement by the American Association of Clinical Endocrinologists (AACE) and the American Diabetes Association (ADA) states that "hyperglycemia in hospitalized patients, irrespective of its cause, is unequivocally associated with adverse outcomes."5 It is important to recognize that hyperglycemia occurs in patients with known or undiagnosed diabetes as well as during acute illness in those with previously normal glucose tolerance.
The Normoglycemia in Intensive Care Evaluation-Survival Using Glucose Algorithm Regulation (NICE-SUGAR) study involved over six thousand adult intensive care unit (ICU) patients who were randomized to intensive glucose control or conventional glucose control.6 Surprisingly, this trial found that intensive glucose control increased the risk of mortality by 14% (odds ratio, 1.14; p=0.02). In addition, there was an increased prevalence of severe hypoglycemia in the intensive control group compared with the conventional control group (6.8% vs. 0.5%, respectively; p&lt;0.001). From this pivotal trial and two others,7,8 Wyoming Medical Center (WMC) realized the importance of controlling hyperglycemia in the hospitalized patient while avoiding the negative impact of resultant hypoglycemia. 
Despite multiple revisions of an IV insulin paper protocol, analysis of data from usage of the paper protocol at WMC shows that in terms of achieving normoglycemia while minimizing hypoglycemia, results were suboptimal. Therefore, through a systematical implementation plan, monitoring of patient blood glucose levels was switched from using a paper IV insulin protocol to a computerized glucose management system. By comparing blood glucose levels using the paper protocol to that of the computerized system, it was determined, that overall, the computerized glucose management system resulted in more rapid and tighter glucose control than the traditional paper protocol. Specifically, a substantial increase in the time spent within the target blood glucose concentration range, as well as a decrease in the prevalence of severe hypoglycemia (BG &lt; 40 mg/dL), clinical hypoglycemia (BG &lt; 70 mg/dL), and hyperglycemia (BG &gt; 180 mg/dL), was witnessed in the first five months after implementation of the computerized glucose management system. The computerized system achieved target concentrations in greater than 75% of all readings while minimizing the risk of hypoglycemia. The prevalence of hypoglycemia (BG &lt; 70 mg/dL) with the use of the computer glucose management system was well under 1%.

When compared to the previous paper protocol, implementation of a computerized glucose management system results in a substantial increase in blood glucose concentration measurements within the target range. Using a computerized glucose management system to monitor blood glucose levels, decreases in severe hypoglycemia (&lt;40 mg/dL), clinical hypoglycemia (&lt;70 mg/dL), and hyperglycemia (&gt;180 mg/dL) also can be observed.

Diabetes mellitus is a major independent risk factor for increased morbidity and mortality in the hospitalized patient, and elevated blood glucose ...

Screening for Melanoma Modifiers using a Zebrafish Autochthonous Tumor Model

Genomic studies of human cancers have yielded a wealth of information about genes that are altered in tumors1,2,3. A challenge arising from these studies is that many genes are altered, and it can be difficult to distinguish genetic alterations that drove tumorigenesis from that those arose incidentally during transformation. To draw this distinction it is beneficial to have an assay that can quantitatively measure the effect of an altered gene on tumor initiation and other processes that enable tumors to persist and disseminate. Here we present a rapid means to screen large numbers of candidate melanoma modifiers in zebrafish using an autochthonous tumor model4 that encompasses steps required for melanoma initiation and maintenance. A key reagent in this assay is the miniCoopR vector, which couples a wild-type copy of the mitfa melanocyte specification factor to a Gateway recombination cassette into which candidate melanoma genes can be recombined5. The miniCoopR vector has a mitfa rescuing minigene which contains the promoter, open reading frame and 3'-untranslated region of the wild-type mitfa gene. It allows us to make constructs using full-length open reading frames of candidate melanoma modifiers. These individual clones can then be injected into single cell Tg(mitfa:BRAFV600E);p53(lf);mitfa(lf)zebrafish embryos. The miniCoopR vector gets integrated by Tol2-mediated transgenesis6 and rescues melanocytes. Because they are physically coupled to the mitfa rescuing minigene, candidate genes are expressed in rescued melanocytes, some of which will transform and develop into tumors. The effect of a candidate gene on melanoma initiation and melanoma cell properties can be measured using melanoma-free survival curves, invasion assays, antibody staining and transplantation assays.

A rapid way to screen for melanoma modifiers using a zebrafish autochthonous tumor model is presented. It takes advantage of the miniCoopR vector which allows for expression of candidate melanoma genes in melanocytes. A method to obtain melanoma-free survival curves, an invasion assay, a protocol for antibody staining of scale melanocytes and a melanoma transplantation assay are described.

Genomic studies of  human cancers have yielded a wealth of information about genes that are altered  in tumors1,2,3. A challenge arising from these ...

Echocardiographic Approaches and Protocols for Comprehensive Phenotypic Characterization of Valvular Heart Disease in Mice

The aim of this manuscript and accompanying video is to provide an overview of the methods and approaches used for imaging heart valve function in rodents, with detailed descriptions of the appropriate methods for anesthesia, the echocardiographic windows used, the imaging planes and probe orientations for image acquisition, the methods for data analysis, and the limitations of emerging technologies for the evaluation of cardiac and valvular function. Importantly, we also highlight several future areas of research in cardiac and heart valve imaging that may be leveraged to gain insights into the pathogenesis of valve disease in preclinical animal models. We propose that using a systematic approach to evaluating cardiac and heart valve function in mice can result in more robust and reproducible data, as well as facilitate the discovery of previously underappreciated phenotypes in genetically-altered and/or physiologically-stressed mice.

This protocol provides a detailed description of the echocardiographic approach for comprehensive phenotyping of heart and heart valve function in mice.

The aim of this manuscript and accompanying video is to provide an overview of the methods and approaches used for imaging heart valve function in ...

Evaluating the Procedure for Performing Awake Cystometry in a Mouse Model

Awake filling cystometry has been used for a long time to evaluate bladder function in freely moving mice, however, the specific methods used, vary among laboratories. The goal of this study was to describe the microsurgical procedure used to implant an intravesical tube and the experimental technique for recording urinary bladder pressure in an awake, freely moving mouse. In addition, experimental data is presented to show how surgery, as well as tubing type and size, affect lower urinary tract function and recording sensitivity. The effect of tube diameter on pressure recording was assessed in both polyethylene and polyurethane tubing with different internal diameters. Subsequently, the best performing tube from both materials was surgically implanted into the dome of the urinary bladder of male C57BL/6 mice. Twelve-hour, overnight micturition frequency was recorded in healthy, intact animals and animals 2, 3, 5, and 7 days post-surgery. At harvest, bladders were assessed for signs of swelling using gross observation and were subsequently processed for pathological analysis. The greatest extent of bladder swelling was observed on day 2 and 3, which correlated with behavioral voiding data showing significantly impaired bladder function. By day 5, bladder histology and voiding frequency had normalized. Based on the literature and evidence provided by our studies, we propose the following steps for in vivo recording of intravesical pressure and voided volume in an awake mouse: 1) Perform the surgery using an operating microscope and microsurgical tools, 2) Use polyethylene-10 tubing to minimize movement artifacts, and 3) Perform cystometry on post-operative day 5, when bladder swelling resolves.

This study describes the surgical procedures and experimental techniques for performing awake cystometry in a freely moving mouse. In addition, it provides experimental evidence to support its optimization and standardization.

Awake filling cystometry has been used for a long time to evaluate bladder function in freely moving mice, however, the specific methods used, vary among ...

A Rat Carotid Artery Pressure-Controlled Segmental Balloon Injury with Periadventitial Therapeutic Application

Cardiovascular disease remains the leading cause of death and disability worldwide, in part due to atherosclerosis. Atherosclerotic plaque narrows the luminal surface area in arteries thereby reducing adequate blood flow to organs and distal tissues. Clinically, revascularization procedures such as balloon angioplasty with or without stent placement aim to restore blood flow. Although these procedures reestablish blood flow by reducing plaque burden, they damage the vessel wall, which initiates the arterial healing response. The prolonged healing response causes arterial restenosis, or re-narrowing, ultimately limiting the long-term success of these revascularization procedures. Therefore, preclinical animal models are integral for analyzing the pathophysiological mechanisms driving restenosis, and provide the opportunity to test novel therapeutic strategies. Murine models are cheaper and easier to operate on than large animal models. Balloon or wire injury are the two commonly accepted injury modalities used in murine models. Balloon injury models in particular mimic the clinical angioplasty procedure and cause adequate damage to the artery for the development of restenosis. Herein we describe the surgical details for performing and histologically analyzing the modified, pressure-controlled rat carotid artery balloon injury model. Additionally, this protocol highlights how local periadventitial application of therapeutics can be used to inhibit neointimal hyperplasia. Lastly, we present light sheet fluorescence microscopy as a novel approach for imaging and visualizing the arterial injury in three-dimensions.

The rat carotid artery balloon injury mimics the clinical angioplasty procedure performed to restore blood flow in atherosclerotic vessels. This model induces the arterial injury response by distending the arterial wall, and denuding the intimal layer of endothelial cells, ultimately causing remodeling and an intimal hyperplastic response.

Cardiovascular disease remains the leading cause of death and disability worldwide, in part due to atherosclerosis. Atherosclerotic plaque narrows the ...

Establishing In Situ Closed Circuit Perfusion of Lower Abdominal Organs and Hind Limbs in Mice

Ex vivo perfusion is an important physiological tool to study the function of isolated organs (e.g. liver, kidneys). At the same time, due to the small size of mouse organs, ex vivo perfusion of bone, bladder, skin, prostate, and reproductive organs is challenging or not feasible. Here, we report for the first time an in situ lower body perfusion circuit in mice that includes the above tissues, but bypasses the main clearance organs (kidney, liver, and spleen). The circuit is established by cannulating the abdominal aorta and inferior vena cava above the iliac artery and vein and cauterizing peripheral blood vessels. Perfusion is performed via a peristaltic pump with perfusate flow maintained for up to 2 h. In situ staining with fluorescent lectin and Hoechst solution confirmed that the microvasculature was successfully perfused. This mouse model can be a very useful tool for studying pathological processes as well as mechanisms of drug delivery, migration/metastasis of circulating tumor cells into/from the tumor, and interactions of immune system with perfused organs and tissues.

A protocol is described for in situ perfusion of the mouse lower body, including the bladder, the prostate, sex organs, bone, muscle and foot skin.

Ex vivo perfusion is an important physiological tool to study the function of isolated organs (e.g. liver, kidneys). At the same time, due to the small ...

Using a Chemical Biopsy for Graft Quality Assessment

Kidney transplantation is a life-saving treatment for a large number of people with end-stage renal dysfunction worldwide. The procedure is associated with an increased survival rate and greater quality of patient&#8217;s life when compared to conventional dialysis. Regrettably, transplantology suffers from a lack of reliable methods for organ quality assessment. Standard diagnostic techniques are limited to macroscopic appearance inspection or invasive tissue biopsy, which do not provide comprehensive information about the graft. The proposed protocol aims to introduce solid phase microextraction (SPME) as an ideal analytical method for comprehensive metabolomics and lipidomic analysis of all low molecular compounds present in kidneys allocated for transplantation. The small size of the SPME probe enables performance of a chemical biopsy, which enables extraction of metabolites directly from the organ without any tissue collection. The minimum invasiveness of the method permits execution of multiple analyses over time: directly after organ harvesting, during its preservation, and immediately after revascularization at the recipient&#8217;s body. It is hypothesized that the combination of this novel sampling method with a high-resolution mass spectrometer will allow for discrimination of a set of characteristic compounds that could serve as biological markers of graft quality and indicators of possible development of organ dysfunction.

The protocol presents utilization of the chemical biopsy approach followed by comprehensive metabolomic and lipidomic analysis for quality assessment of kidney grafts allocated for transplantation.

Kidney transplantation is a life-saving treatment for a large number of people with end-stage renal dysfunction worldwide. The procedure is associated ...

A Surgical Model of Heart Failure with Preserved Ejection Fraction in Tibetan Minipigs

More than half of heart failure (HF) cases are classified as heart failure with preserved ejection fraction (HFpEF) worldwide. Large animal models are limited for investigating the fundamental mechanisms of HFpEF and identifying potential therapeutic targets. This work provides a detailed description of the surgical procedure of descending aortic constriction (DAC) in Tibetan minipigs to establish a large animal model of HFpEF. This model used a precisely controlled constriction of the descending aorta to induce chronic pressure overload in the left ventricle. Echocardiography was used to evaluate the morphological and functional changes in the heart. After 12 weeks of DAC stress, the ventricular septum was hypertrophic, but the thickness of the posterior wall was significantly reduced, accompanied by dilation of the left ventricle. However, the LV ejection fraction of the model hearts was maintained at &gt;50% during the 12-week period. Furthermore, the DAC model displayed cardiac damage, including fibrosis, inflammation, and cardiomyocyte hypertrophy. Heart failure marker levels were significantly elevated in the DAC group. This DAC-induced HFpEF in minipigs is a powerful tool for investigating molecular mechanisms of this disease and for preclinical testing.

The present protocol describes a step-by-step procedure to establish a minipig model of heart failure with preserved ejection fraction using descending aortic constriction. The methods for evaluating cardiac morphology, histology, and function of this disease model are also presented.

More than half of heart failure (HF) cases are classified as heart failure with preserved ejection fraction (HFpEF) worldwide. Large animal models are ...

A Personalized 3D-Printed Model for Preoperative Evaluation in Thyroid Surgery

The anatomic structure of the surgical area of thyroid cancer is complex. It is very important to comprehensively and carefully evaluate the tumor location and its relation with the capsule, trachea, esophagus, nerves, and blood vessels before operation. This paper introduces an innovative 3D-printed model establishment method based on computerized tomography (CT) DICOM images. We established a personalized 3D-printed model of the cervical thyroid surgery field for each patient who needed thyroid surgery to help clinicians evaluate the key points and difficulties of the surgery and select the operation methods of key parts as a basis. The results showed that this model is conducive to preoperative discussion and the formulation of operation strategies. In particular, as a result of the clear display of the recurrent laryngeal nerve and parathyroid gland locations in the thyroid operation field, injury to them can be avoided during surgery, the difficulty of thyroid surgery reduced, and the incidence of postoperative hypoparathyroidism and complications related to recurrent laryngeal nerve injury reduced too. Moreover, this 3D-printed model is intuitive and aids communication for the signing of informed consent by patients before surgery.

Here, a new method of establishing a personalized 3D-printed model for preoperative evaluation of thyroid surgery is proposed. It is conducive to preoperative discussion, reducing the difficulty of thyroid surgery.