The authors acknowledge the following funding sources, Whittier Foundation, Harrington Foundation, National Institutes of Health and Research to Prevent Blindness.

All enucleated eyes were obtained from an abattoir and all experiments were performed in accordance with institutional biosafety laws.
<ol>
	<li>Secure enucleated eye down on a surface. Do this by placing tissue pins through the excess tissue around the eye and securing it down into a Styrofoam board.</li>
	<li>Dissect and detach perilimbal conjunctiva from eye.
	<ol>
		<li>Use fine forceps (0.3 forceps) and microscissors (Westcott scissors) to incise the conjunctiva at the limbus and bluntly dissect it off the sclera. Cut the conjunctiva along the limbus as the blunt dissection proceeds to allow further dissection.</li>
		<li>Remove conjunctiva all the way around the eye (360 degrees) to expose as much sclera as possible. 
		NOTE: It is helpful to leave a small amount of conjunctiva to facilitate fixating the eye with the surgical pins or a forceps during the rest of the procedure.</li>
	</ol>
	</li>
	<li>Create a full thickness scleral flap along one side of the eye (scalpel blade 69).
	<ol>
		<li>Make a ~5 mm scleral incision parallel to the limbus and 3 mm posterior to the limbus by gently cutting into the sclera with a scalpel (scalpel blade 11) until darkly pigmented choroid is visible. Be careful not to incise the choroid itself.</li>
		<li>Carefully dissect along the plane between the sclera and choroid, either with scissors (using blunt dissection) or with the scalpel, until it is possible to enlarge the potential space between these tissues by pushing the choroid gently inward.</li>
		<li>Make another scleral incision perpendicular to the first scleral incision with sharp microscissors, creating a T-shaped incision.</li>
		<li>Then continue to bluntly dissect in a circumferential fashion to remove the scleral tissue from the underlying choroid and gently push the choroid away from the sclera as mentioned above.</li>
		<li>Enlarge the scleral flap as needed.
		<ol>
			<li>Gently blunt dissect the choroid away from the sclera throughout the process.</li>
			<li>Enlarge the flap until the incision made perpendicular to the limbus reaches the optic nerve and the incision made parallel to the limbus is at least one-third of the eye circumference (45&#176;).</li>
			<li>Use the scleral flap as a source of leverage for manipulating the eye during blunt dissection. The counter-traction on the flap makes it easier for blunt dissection.</li>
		</ol>
		</li>
		<li>Repeat the previous step on the other scleral flap.</li>
	</ol>
	</li>
	<li>Cut away the scleral flaps to expose a large area of choroid.</li>
	<li>Continue the incision made in step 3 around the eye&#8217;s circumference (360 degrees).</li>
	<li>Remove the remaining choroid-retina tissue.
	<ol>
		<li>Within the exposed region, use a cotton-tip to gently brush off the choroid-retina tissue remaining. Alternatively, gently grab the tissue with forceps and peel it off the underlying vitreous body.</li>
		<li>If necessary make an incision into the choroid starting from the optic nerve. Then peel away the choroid gently to expose the retina and vitreous cortex.</li>
	</ol>
	</li>
	<li>Continue blunt dissecting the choroid away from the sclera and then peel away the choroid to obtain the whole, intact vitreous.</li>
	<li>Use the scleral rim attached to the cornea to position the whole vitreous in desired location. At this point, the vitreous is attached to the anterior sclera and lens.</li>
	<li>Blunt dissect the vitreous from the inside of the sclera, around the lens, removing all sclera.</li>
	<li>Use a blunt tool to scoop the lens away from the vitreous if need be. Use the sample for various vitreodynamic experiments.
	<ol>
		<li>Place sample in a glass beaker with known surface area exposed to air. Place oxygen sensitive probe at the edge of the sample. Use a micro-manipulator to move the probe to a known distance (r) into the sample.</li>
		<li>Use Fick&#8217;s laws of diffusion to obtain the theoretical diffusion equation. With the data collected in step 10.1, obtain the experimental diffusion coefficient/reaction term etc.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Siggers, J. H., Ethier, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluid+Mechanics+of+the+Eye.">Fluid Mechanics of the Eye.</a> Annual Review of Fluid Mechanics. 44 (1), 347-372 (2012).</li><li>Sebag, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Age-related+changes+in+human+vitreous+structure.">Age-related changes in human vitreous structure.</a> Graefes Arch Clin Exp Ophthalmol. 225 (2), 89-93 (1987).</li><li>Grignolo, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fibrous+components+of+the+vitreous+body.">Fibrous components of the vitreous body.</a> AMA Arch Ophthalmol. 47 (6), 760-774 (1952).</li><li>Gisladottir, S., Loftsson, T., Stefansson, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diffusion+characteristics+of+vitreous+humour+and+saline+solution+follow+the+Stokes+Einstein+equation.">Diffusion characteristics of vitreous humour and saline solution follow the Stokes Einstein equation.</a> G Graefes Arch Clin Exp Ophthalmol. 247 (12), 1677-1684 (2009).</li><li>Xu, J., Heys, J. J., Barocas, V. H., Randolph, T. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Permeability+and+diffusion+in+vitreous+humor:+implications+for+drug+delivery.">Permeability and diffusion in vitreous humor: implications for drug delivery.</a> Pharm Res. 17 (6), 664-669 (2000).</li><li>Watts, F., Tan, L. E., Wilson, C. G., Girkin, J. M., Tassieri, M., Wright, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigating+the+micro-rheology+of+the+vitreous+humor+using+an+optically+trapped+local+probe.">Investigating the micro-rheology of the vitreous humor using an optically trapped local probe.</a> Journal of Optics. 16 (1), 015301 (2014).</li><li>Skeie, J. M., Mahajan, V. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissection+of+human+vitreous+body+elements+for+proteomic+analysis.">Dissection of human vitreous body elements for proteomic analysis.</a> J Vis Exp. (47), e2455 (2011).</li><li>Abdallah, W., Ameri, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vitreal+oxygenation+in+retinal+ischemia+reperfusion.">Vitreal oxygenation in retinal ischemia reperfusion.</a> Invest Ophthalmol Vis Sci. 52 (2), 1035-1042 (2011).</li><li>Goldenberg, D., Trese, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pharmacologic+vitreodynamics:+what+is+it?+Why+is+it+important.">Pharmacologic vitreodynamics: what is it? Why is it important.</a> Expert Review of Ophthalmology. 3 (3), 273-277 (2008).</li><li>Choonara, Y. E., Pillay, V., Danckwerts, M. P., Carmichael, T. R., du Toit, L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+implantable+intravitreal+drug+delivery+technologies+for+the+treatment+of+posterior+segment+eye+diseases.">A review of implantable intravitreal drug delivery technologies for the treatment of posterior segment eye diseases.</a> J Pharm Sci. 99 (5), 2219-2239 (2010).</li><li>Balachandran, R. K., Barocas, V. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Computer+modeling+of+drug+delivery+to+the+posterior+eye:+effect+of+active+transport+and+loss+to+choroidal+blood+flow.">Computer modeling of drug delivery to the posterior eye: effect of active transport and loss to choroidal blood flow.</a> Pharm Res. 25 (11), 2685-2696 (2008).</li><li>Smith, C. a., Newson, T. a., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+framework+for+modeling+ocular+drug+transport+and+flow+through+the+eye+using+micro-CT.">A framework for modeling ocular drug transport and flow through the eye using micro-CT.</a> Phys Med Biol. 57 (19), 6295-6307 (2012).</li><li>Quiram, P. A., Leverenz, V. R., Baker, R. M., Dang, L., Giblin, F. J., Trese, 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=Microplasmin-induced+posterior+vitreous+detachment+affects+vitreous+oxygen+levels.">Microplasmin-induced posterior vitreous detachment affects vitreous oxygen levels.</a> Retina. 27 (8), 1090-1096 (2007).</li><li>Shui, Y., Holekamp, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+gel+state+of+the+vitreous+and+ascorbate-dependent+oxygen+consumption:+relationship+to+the+etiology+of+nuclear+cataracts.">The gel state of the vitreous and ascorbate-dependent oxygen consumption: relationship to the etiology of nuclear cataracts.</a> Arch Ophthalmol. 127 (4), 475-482 (2009).</li><li>Burk, S. E., Da Mata, A. P., Snyder, M. E., Schneider, S., Osher, R. H., Cionni, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualizing+vitreous+using+kenalog+suspension.">Visualizing vitreous using kenalog suspension.</a> J Cataract Refract Surg. 29 (4), 645-651 (2003).</li><li>Spaide, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualization+of+the+Posterior+Vitreous+with+Dynamic+Focusing+and+Windowed+Averaging+Swept+Source+Optical+Coherence+Tomography.">Visualization of the Posterior Vitreous with Dynamic Focusing and Windowed Averaging Swept Source Optical Coherence Tomography.</a> Am J Ophthalmol. S0002-9394 (14), 00537-00536 (2014).</li><li>Domalpally, A., Gangaputra, S., Danis, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Diseases of the Vitreo-Macular Interface. 21, 21-27 (2014).</li><li>Stocchino, R., Repetto, A., Cafferata, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+investigation+of+vitreous+humour+motion+within+a+human+eye+model.">Experimental investigation of vitreous humour motion within a human eye model.</a> Phys Med Biol. 50 (19), 4729-4743 (2005).</li></ol>

The authors have nothing to disclose.

There are two critical steps that must be carefully performed during vitreous dissection. Step 3, creating a full thickness scleral flap, is crucial to the entire dissection. Care should be taken to not cut into the choroid when creating the full thickness scleral flap. The other critical step is dissecting away the sclera from the choroid. This step must be carefully done to prevent creating multiple holes in the choroid from which the vitreous can spill out. There is a way to modify the protocol and still dissect intac...

The goal of this method is to detail a technique to isolate a whole, intact vitreous body, with the vitreous core and cortex intact, from a cadaver eye, for the purposes of vitreodynamic analysis. As the field of vitreous physiology has grown, multi-disciplinary researchers, such as fluid mechanics researchers, are investigating the physical and biomechanical properties of the vitreous1. To this end, it is essential to detail a technique to isolate the whole, intact vitreous body to aid multi-disciplinary researchers.
Sebag et al.2 and others3 performed elegant whole vitreous dissections on human cadaver eyes and showed illustrations of the results. However, the technique used was not described in detail and non-experts would not be able to replicate the method independently. Other studies have harvested vitreous from cadaver eyes using simpler methods such as aspiration or partial dissection, both of which do not result in a whole, intact vitreous body. Gisladottis et al.4 and Xu et al.5 investigate permeability in vitreous humor harvested from cadaver eyes. However, since no method of vitreous extraction was described, it was assumed that they aspirated the vitreous humor with a syringe. Watts et al.6 went one step further by describing a method of isolating rabbit vitreous humor with a surgical technique. However, this method results in an isolation of just the vitreous core and not the vitreous cortex. Skeie et al.7 later organized the vitreous into 4 unique regions and elegantly described a method to dissect out each part for analysis. This technique however, does not result in an intact vitreous as a whole.
The current technique was developed to facilitate biophysical experiments that are currently only performed in cadaver eyes. Previous methods, as described above, are limited because 1) none completely isolate the whole vitreous body, 2) harvested vitreous core and cortex are homogenized, 3) vitreous anatomical structure is not maintained, or 4) dissection techniques are not adequately detailed for replication by researchers in other fields. In addition, due to the opacity of sclera and choroid, visualization of the vitreous body is limited in the intact eyeball. This limits the precision and feasibility of measurements that can be made inside the whole eye. In addition, the anatomical structures surrounding the vitreous can confound the study of biochemical and physical properties of the vitreous.
In recent years, the body of vitreous science has grown tremendously and there is reason to believe that the whole vitreous body has different properties than its individual parts. There is growing interest in investigating the physical, biomechanical, and chemical properties of the vitreous for vitreodynamics research, which has applications in clinical medicine such as drug delivery, intravitreal oxygenation8 and vitrectomy. Pharmacological vitreodynamics, which uses pharmacologic agents to manipulate the vitreous, can be used to improve vitrectomy outcomes9. Biomechanical properties are used to model vitreous fluid flow, which can be used to improve intravitreal drug delivery technologies10&#8211;12. Physical properties of various segments of the vitreous are crucial to understanding vitreo-retinal oxygen transport13. The proposed vitreous dissection technique can be used to study various properties of the intact vitreous humor. It enables bench-top experiments to be done on whole, intact vitreous bodies with better visualization.
In summary, current methods for study of the vitreous are either not adequately described, or result in an incomplete isolation the vitreous core and cortex. Therefore, there is a need to perform experiments in a transparent eye model while retaining the anatomy of the vitreous that exists in the cadaver eye.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>0.3 forceps</td>
			<td>Storz Opthalmics</td>
			<td>E1793</td>
			<td></td>
		</tr>
		<tr>
			<td>Westcott Tenotomy Scissors Curved Right</td>
			<td>Storz Opthalmics</td>
			<td>E3320 R</td>
			<td></td>
		</tr>
		<tr>
			<td>Scalpel Handle No. 3</td>
			<td>VWR</td>
			<td>25607-947</td>
			<td></td>
		</tr>
		<tr>
			<td>Scalpel Blade, #11, for #3 Handle</td>
			<td>VWR</td>
			<td>470174-844</td>
			<td></td>
		</tr>
	</tbody>
</table>

whole vitreous humor dissection for vitreodynamic analysis

The authors propose an effective technique to isolate whole, intact vitreous core and cortex from post mortem enucleated porcine eyes. While previous studies have shown the results of such dissections, the detailed steps have not been described, precluding researchers outside the field from replicating their methods. Other studies harvest vitreous either through aspiration, which does not maintain the vitreous structure anatomy, or through partial dissection, which only isolates the vitreous core. The proposed method isolates the whole vitreous body, with the vitreous core and cortex intact, while maintaining vitreous anatomy and structural integrity. In this method, a full thickness scleral flap in an enucleated porcine eye is first created and through this, the choroid tissue can be separated from the sclera. The scleral flap is then expanded and the choroid is completely separated from the sclera. Finally the choroid-retina tissue is peeled off the vitreous to leave an isolated intact vitreous body. The proposed vitreous dissection technique can be used to study physical properties of the vitreous humor. In particular, this method has significance for experimental studies involving drug delivery, vitreo-retinal oxygen transport, and intraocular convection.

Following the protocol will lead to a successful vitreous dissection with the core and cortex (Figure 3) intact. This is evident from the residual pieces of retina adhered to the vitreous cortex. Intact whole vitreous humor can be used in several ways for specific vitreodynamic experiments. In our case, the diffusion rate of oxygen in intact vitreous humor and it&#8217;s corresponding time constant was studied (Figure 2). Vitreous that was dissected (core and cortex) using our method was...

Watch this Scientific Journal Video about Whole Vitreous Humor Dissection for Vitreodynamic Analysis at JoVE.com

Whole Vitreous Humor Dissection for Vitreodynamic Analysis

The goal of this protocol is to show an effective technique to isolate whole, intact vitreous core and cortex from post mortem enucleated porcine eyes.

The authors propose an effective technique to isolate whole, intact vitreous core and cortex from post mortem enucleated porcine eyes. While previous ...

whole-vitreous-humor-dissection-for-vitreodynamic-analysis

Research

JoVE Journal

Medicine

11.3K vues.  University of Southern California. The goal of this protocol is to show an effective technique to isolate whole, intact vitreous core and cortex from post mortem enucleated porcine eyes.

Vidéo: Whole Vitreous Humor Dissection for Vitreodynamic Analysis

Dissection of Human Vitreous Body Elements for Proteomic Analysis

The vitreous is an optically clear, collagenous extracellular matrix that fills the inside of the eye and overlies the retina. 1,2 Abnormal interactions between vitreous substructures and the retina underlie several vitreoretinal diseases, including retinal tear and detachment, macular pucker, macular hole, age-related macular degeneration, vitreomacular traction, proliferative vitreoretinopathy, proliferative diabetic retinopathy, and inherited vitreoretinopathies. 1,2 The molecular composition of the vitreous substructures is not known. Since the vitreous body is transparent with limited surgical access, it has been difficult to study its substructures at the molecular level. We developed a method to separate and preserve these tissues for proteomic and biochemical analysis. The dissection technique in this experimental video shows how to isolate vitreous base, anterior hyaloid, vitreous core, and vitreous cortex from postmortem human eyes. One-dimensional SDS-PAGE analyses of each vitreous component showed that our dissection technique resulted in four unique protein profiles corresponding to each substructure of the human vitreous body. Identification of differentially compartmentalized proteins will reveal candidate molecules underlying various vitreoretinal diseases.

This video shows an effective technique for differentiating and dissecting the various semi-transparent structures of the human vitreous body in post mortem eyes.

The vitreous is an optically clear, collagenous extracellular matrix that fills the inside of the eye and overlies the retina. 1,2 Abnormal interactions ...

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.

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 ...

3D Whole-heart Myocardial Tissue Analysis

Cardiac regenerative therapies aim to protect and repair the injured heart in patients with ischemic heart disease. By injecting stem cells or other biologicals that enhance angio- or vasculogenesis into the infarct border zone (IBZ), tissue perfusion is improved, and the myocardium can be protected from further damage. For maximum therapeutic effect, it is hypothesized that the regenerative substance is best delivered to the IBZ. This requires accurate injections and has led to the development of new injection techniques. To validate these new techniques, we have designed a validation protocol based on myocardial tissue analysis. This protocol includes whole-heart myocardial tissue processing that enables detailed two-dimensional (2D) and three-dimensional (3D) analysis of the cardiac anatomy and intramyocardial injections. In a pig, myocardial infarction was created by a 90-min occlusion of the left anterior descending coronary artery. Four weeks later, a mixture of a hydrogel with superparamagnetic iron oxide particles (SPIOs) and fluorescent beads was injected in the IBZ using a minimally-invasive endocardial approach. 1 h after the injection procedure, the pig was euthanized, and the heart was excised and embedded in agarose (agar). After the solidification of the agar, magnetic resonance imaging (MRI), slicing of the heart, and fluorescence imaging were performed. After image post-processing, 3D analysis was performed to assess the IBZ targeting accuracy. This protocol provides a structured and reproducible method for the assessment of the targeting accuracy of intramyocardial injections into the IBZ. The protocol can be easily used when the processing of scar tissue and/or validation of the injection accuracy of the whole heart is desired.

This protocol describes a novel method for the 3D comparison of whole-heart myocardial tissue with MRI. This is designed for the accurate assessment of intramyocardial injections in the infarct border zone of a chronic porcine model of myocardial infarction.

Cardiac regenerative therapies aim to protect and repair the injured heart in patients with ischemic heart disease. By injecting stem cells or other ...

Dissection of the Mouse Pancreas for Histological Analysis and Metabolic Profiling

We have been investigating the pancreas specific transcription factor, 1a cre-recombinase; lox-stop-lox- Kristen rat sarcoma, glycine to aspartic acid at the 12 codon (Ptf1acre/+;LSL-KrasG12D/+) mouse strain as a model of human pancreatic cancer. The goal of our current studies is to identify novel metabolic biomarkers of pancreatic cancer progression. We have performed metabolic profiling of urine, feces, blood, and pancreas tissue extracts, as well as histological analyses of the pancreas to stage the cancer progression. The mouse pancreas is not a well-defined solid organ like in humans, but rather is a diffusely distributed soft tissue that is not easily identified by individuals unfamiliar with mouse internal anatomy or by individuals that have little or no experience performing mouse organ dissections. The purpose of this article is to provide a detailed step-wise visual demonstration to guide novices in the removal of the mouse pancreas by dissection. This article should be especially valuable to students and investigators new to research that requires harvesting of the mouse pancreas by dissection for metabolic profiling or histological analyses.

This video article provides a detailed demonstration of the procedures required to successfully remove the pancreas from a mouse by dissection for histological analysis and metabolic profiling.

We have been investigating the pancreas specific transcription factor, 1a cre-recombinase; lox-stop-lox- Kristen rat sarcoma, glycine to aspartic acid at ...

Discovering Middle Ear Anatomy by Transcanal Endoscopic Ear Surgery: A Dissection Manual

The middle ear is located in the center of the temporal bone and bears a highly complex anatomy. The recently introduced exclusively endoscopic transcanal approach to the middle ear is a minimally invasive technique sparing the bone and mucosa of the mastoid bone, since the middle ear is accessed through the external auditory canal. This emerging method has several advantages over the traditional (microscopic) approaches to the middle ear such as the panoramic wide-angle views of the anatomy, the possibility to approach and magnify tiny structures, and the possibility of looking around the corner using angled endoscopes.
The cadaveric dissection method presented here consists of an overview on the technical requirements and a precise description of a step-by-step protocol to discover the anatomy of the middle ear. Each step and anatomical structure is carefully described in order to provide a comprehensive guide to endoscopic ear anatomy. In our opinion, this is particularly important to any novice in endoscopic ear surgery as it provides thorough anatomical knowledge and may improve surgical skills.

The aim of this article is to describe the methodology of exclusively endoscopic cadaveric middle ear dissection. Moreover, we aim to provide a comprehensive guide to endoscopic middle ear anatomy.

The middle ear is located in the center of the temporal bone and bears a highly complex anatomy. The recently introduced exclusively endoscopic transcanal ...

Dissection and Explant Culture of Murine Allantois for the In Vitro Analysis of Allantoic Attachment

The placenta is essential for the growth and development of mammalian embryos. For this reason, numerous genetic alterations and likely also environmental insults that disturb placenta development or function can cause early pregnancy loss in mice and humans. Nevertheless, simple in vitro assays to screen for potential effects on placenta formation are lacking. Here, we focus on modeling the first and critical step in placenta formation, which consists of the attachment of the allantois to the chorion. We describe a method to rapidly assess the attachment of allantoic explants on immobilized &#945;4&#946;1 integrin, which serves as a chorio-mimetic substrate.This in vitro approach enables a qualitative evaluation of the attachment and spreading behavior of multiple allantois explants at different consecutive time points. The protocol may be used to investigate the effect of targeted mouse mutations, drugs, or various environmental factors that have been linked to pregnancy complications or fetal loss on allantois attachment ex vivo.

Dissection and Explant Culture of Murine Allantois for the In Vitro Analysis of Allantoic Attachment

We describe an in vitro assay to model chorioallantoic attachment, the first step in placenta formation. The protocol demonstrates the dissection and explant culture of murine allantoides on immobilized &#945;4&#946;1 integrin. Allantois attachment is evaluated microscopically at pre-determined time points.

The placenta is essential for the growth and development of mammalian embryos. For this reason, numerous genetic alterations and likely also environmental ...

Whole-brain Segmentation and Change-point Analysis of Anatomical Brain MRI&#8212;Application in Premanifest Huntington's Disease

Recent advances in MRI offer a variety of useful markers to identify neurodegenerative diseases. In Huntington&#39;s disease (HD), regional brain atrophy begins many years prior to the motor onset (during the &#34;premanifest&#34; period), but the spatiotemporal pattern of regional atrophy across the brain has not been fully characterized. Here we demonstrate an online cloud-computing platform, &#34;MRICloud&#34;, which provides atlas-based whole-brain segmentation of T1-weighted images at multiple granularity levels, and thereby, enables us to access the regional features of brain anatomy. We then describe a regression model that detects statistically significant inflection points, at which regional brain atrophy starts to be noticeable, i.e. the &#34;change-point&#34;, with respect to a disease progression index. We used the CAG-age product (CAP) score to index the disease progression in HD patients. Change-point analysis of the volumetric measurements from the segmentation pipeline, therefore, provides important information of the order and pattern of structural atrophy across the brain. The paper illustrates the use of these techniques on T1-weighted MRI data of premanifest HD subjects from a large multicenter PREDICT-HD study. This design potentially has wide applications in a range of neurodegenerative diseases to investigate the dynamic changes of brain anatomy.

Whole-brain Segmentation and Change-point Analysis of Anatomical Brain MRI&amp;#8212;Application in Premanifest Huntington&#039;s Disease

This paper describes a statistical model for volumetric MRI data analysis, which identifies the &#34;change-point&#34; when brain atrophy begins in premanifest Huntington&#39;s disease. Whole-brain mapping of the change-points is achieved based on brain volumes obtained using an atlas-based segmentation pipeline of T1-weighted images.

Recent advances in MRI offer a variety of useful markers to identify neurodegenerative diseases. In Huntington&#39;s disease (HD), regional brain atrophy ...

Quantitative Micro-CT Analysis of Aortopathy in a Mouse Model of &#946;-aminopropionitrile-induced Aortic Aneurysm and Dissection

Aortic aneurysm and dissection is associated with significant morbidity and mortality in the population and can be highly lethal. While animal models of aortic disease exist, in vivo imaging of the vasculature has been limited. In recent years, micro-computerized tomography (micro-CT) has emerged as a preferred modality for imaging both large and small vessels both in vivo and ex vivo. In conjunction with a method of vascular casting, we have successfully used micro-CT to characterize the frequency and distribution of aortic pathology in &#946;-aminopropionitrile-treated C57/Bl6 mice. Technical limitations of this method include variations in the quality of the perfusion introduced by poor animal preparation, the application of proper methodologies for vessel size quantification, and the non-survivability of this procedure. This article details a methodology for the intravascular perfusion of a lead-based radiopaque silicone rubber for the quantitative characterization of aortopathy in a mouse model of aneurysm and dissection. In addition to visualizing aortic pathology, this method may be used for examining other vascular beds in vivo or vascular beds removed post-mortem.

Quantitative Micro-CT Analysis of Aortopathy in a Mouse Model of &amp;#946;-aminopropionitrile-induced Aortic Aneurysm and Dissection

This article describes a detailed methodology of using a radiopaque lead-based silicone rubber to perfuse the murine vasculature for aortic diameter quantification in a mouse model of aortic aneurysm and dissection.

Aortic aneurysm and dissection is associated with significant morbidity and mortality in the population and can be highly lethal. While animal models of ...

Imaging and Analysis of Oil Red O-Stained Whole Aorta Lesions in an Aneurysm Hyperlipidemia Mouse Model

Apolipoprotein E (Apoe)- or low density lipoprotein receptor (Ldlr)-deficient hyperlipidemic mice are the two most commonly used models for atherosclerosis research. They are used to study the impact of a various genetic factors and different cell types on atherosclerotic lesion formation and as well as test the development of new therapies. Isolation, excision of the whole aorta, and quantification of Oil Red O-stained atherosclerotic lesions are basic morphometric methods used to evaluate atherosclerotic burden. The goal of this protocol is to describe an optimized, step-by-step surgical method to dissect, perfuse-fix, isolate, stain, image and analyze atherosclerotic lesions in mouse aortas with Oil Red O. Because atherosclerotic lesions can form anywhere in the entire aortic tree, this whole aorta Oil Red O staining method has the advantage of evaluating lipid-laden plaques in the entire aorta and all branches in a single mouse. In addition to Oil Red O staining, fresh isolated whole aortas can be used for variety of in vitro and in vivo experiments and cell isolations.

This protocol provides a step-by-step procedure to analyze atherosclerotic burden in mice. Investigators can use this protocol to compare the abundance, location, and size of atherosclerotic lesions in different animals.

Apolipoprotein E (Apoe)- or low density lipoprotein receptor (Ldlr)-deficient hyperlipidemic mice are the two most commonly used models for ...

Location, Dissection, and Analysis of the Murine Stellate Ganglion

The autonomic nervous system is a substantial driver of cardiac electrophysiology. Especially&#160;the role of its sympathetic branch is an ongoing matter of investigation in the pathophysiology of ventricular arrhythmias (VA). Neurons in the stellate ganglia (SG)&#160;&#8211;&#160;bilateral star-shaped structures of the sympathetic chain &#8211;&#160;are an important component of the sympathetic infrastructure. The SG are a recognized target for&#160;treatment via cardiac sympathetic denervation in patients with therapy-refractory VA. While neuronal remodeling and glial activation in the SG have been described in patients with VA, the underlying cellular and molecular processes that potentially precede the onset of arrhythmia are only insufficiently understood and should be elucidated to improve autonomic modulation. Mouse models allow us to study sympathetic neuronal remodeling, but identification of the murine SG is challenging for the inexperienced investigator. Thus, in-depth cellular and molecular biological studies of the murine SG are lacking for many common cardiac diseases. Here, we describe a basic repertoire for dissecting and studying the SG in adult mice for analyses at RNA level (RNA isolation for gene expression analyses, in situ hybridization), protein level (immunofluorescent whole mount staining), and cellular level (basic morphology, cell size measurement). We present potential solutions to overcome challenges in the preparation technique, and how to improve staining via quenching of autofluorescence. This allows for the visualization of neurons as well as glial cells via established markers in order to determine cell composition and remodeling processes. The methods presented here allow characterizing the SG to gain further information on autonomic dysfunction in mice prone to VA and can be complemented by additional techniques investigating neuronal and glial components of the autonomic nervous system in the heart.

Pathophysiological changes in the cardiac autonomic nervous system, especially in its sympathetic branch, contribute to the onset and maintenance of ventricular arrhythmias. In the present protocol, we show how to characterize murine stellate ganglia to improve the understanding of the underlying molecular and cellular processes.

The autonomic nervous system is a substantial driver of cardiac electrophysiology. Especially&#160;the role of its sympathetic branch is an ongoing matter ...