Name: using a laminating technique to perform confocal microscopy of the human sclera
Uploaded: 2016-05-06T14:00:00
Description: Watch this Scientific Journal Video about Using a Laminating Technique to Perform Confocal Microscopy of the Human Sclera at JoVE.com

German Research Foundation (FOR2240 "(Lymph) Angiogenesis and Cellular Immunity in Inflammatory Diseases of the Eye" to CC and LMH; HE 6743/2-1 and HE 7643/3-1 to LMH; CU47/6-1 to CC), German Cancer Aid (to LMH and CC), GEROK program University of Cologne (to SLS and LMH), and EU COST BM1302 "Joining Forces to Corneal Regeneration" (to CC).

The use of human tissues must be reviewed and approved by an institutional review board or the equivalent. The work described here was approved by the local ethics committee and had approval for scientific examination. This work was performed according to the Declaration of Helsinki. The human scleral specimens were obtained from the eyes of globe donors (maximum post-mortem time 24 hr) at the Eye Bank of the Department of Ophthalmology, University of Cologne, Germany.
1. Experimental Preparation
<ol>
	<li>Prepa...

<ol>
	<li>Schlereth, S. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enrichment+of+lymphatic+vessel+endothelial+hyaluronan+receptor+1+(LYVE1)-positive+macrophages+around+blood+vessels+in+the+normal+human+sclera.">Enrichment of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE1)-positive macrophages around blood vessels in the normal human sclera.</a> Invest Ophthalmol Vis Sci. 55 (2), 865-872 (2014).</li><li>Schlereth, S. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Absence+of+lymphatic+vessels+in+the+developing+human+sclera.">Absence of lymphatic vessels in the developing human sclera.</a> Exp Eye Res. 125, 203-209 (2014).</li><li>Hos, D., Cursiefen, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lymphatic+vessels+in+the+development+of+tissue+and+organ+rejection.">Lymphatic vessels in the development of tissue and organ rejection.</a> Adv Anat Embryol Cell Biol. 214, 119-141 (2014).</li><li>Hos, D., Schlereth, S. L., Bock, F., Heindl, L. M., Cursiefen, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antilymphangiogenic+therapy+to+promote+transplant+survival+and+to+reduce+cancer+metastasis:+what+can+we+learn+from+the+eye.">Antilymphangiogenic therapy to promote transplant survival and to reduce cancer metastasis: what can we learn from the eye.</a> Semin Cell Dev Biol. , (2014).</li><li>Streilein, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immune+privilege+as+the+result+of+local+tissue+barriers+and+immunosuppressive+microenvironments.">Immune privilege as the result of local tissue barriers and immunosuppressive microenvironments.</a> Curr Opin Immunol. 5 (3), 428-432 (1993).</li><li>Streilein, J. W., Niederkorn, J. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+anterior+chamber-associated+immune+deviation+requires+an+intact,+functional+spleen.">Induction of anterior chamber-associated immune deviation requires an intact, functional spleen.</a> J Exp Med. 153 (5), 1058-1067 (1981).</li><li>Streilein, J. W., Yamada, J., Dana, M. R., Ksander, B. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anterior+chamber-associated+immune+deviation,+ocular+immune+privilege,+and+orthotopic+corneal+allografts.">Anterior chamber-associated immune deviation, ocular immune privilege, and orthotopic corneal allografts.</a> Transplant Proc. 31 (3), 1472-1475 (1999).</li><li>Keeley, F. W., Morin, J. D., Vesely, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+collagen+from+normal+human+sclera.">Characterization of collagen from normal human sclera.</a> Exp Eye Res. 39 (5), 533-542 (1984).</li><li>Lee, R. E., Davison, P. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collagen+composition+and+turnover+in+ocular+tissues+of+the+rabbit.">Collagen composition and turnover in ocular tissues of the rabbit.</a> Exp Eye Res. 32 (6), 737-745 (1981).</li><li>Moses, R. A., Grodzki, W. J., Starcher, B. C., Galione, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Elastin+content+of+the+scleral+spur,+trabecular+mesh,+and+sclera.">Elastin content of the scleral spur, trabecular mesh, and sclera.</a> Invest Ophthalmol Vis Sci. 17 (8), 817-818 (1978).</li><li>Foster, C. S., Sainz de la Maza, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The sclera. , (2012).</li><li>Kiss, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Der+Blutkreislauf+des+Auges.">Der Blutkreislauf des Auges.</a> Ophthalmologica. 106, 225 (1943).</li><li>Ashton, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anatomical+study+of+Schlemm's+canal+and+aqueous+veins+by+means+of+neoprene+casts.+Part+I.+Aqueous+veins.">Anatomical study of Schlemm's canal and aqueous veins by means of neoprene casts. Part I. Aqueous veins.</a> Br J Ophthalmol. 35 (5), 291-303 (1951).</li><li>Ashton, N., Smith, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anatomical+study+of+Schlemm's+canal+and+aqueous+veins+by+means+of+neoprene+casts.+III.+Arterial+relations+of+Schlemm's+canal.">Anatomical study of Schlemm's canal and aqueous veins by means of neoprene casts. III. Arterial relations of Schlemm's canal.</a> Br J Ophthalmol. 37 (10), 577-586 (1953).</li><li>Ashton, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anatomical+study+of+Schlemm's+canal+and+aqueous+veins+by+means+of+neoprene+casts+II.+Aqueous+veins.">Anatomical study of Schlemm's canal and aqueous veins by means of neoprene casts II. Aqueous veins.</a> Br J Ophthalmol. 36 (5), 265-267 (1952).</li><li>Hayreh, S. S., Scott, W. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescein+iris+angiography.+II.+Disturbances+in+iris+circulation+following+strabismus+operation+on+the+various+recti.">Fluorescein iris angiography. II. Disturbances in iris circulation following strabismus operation on the various recti.</a> Arch Ophthalmol. 96 (8), 1390-1400 (1978).</li><li>Virdi, P. S., Hayreh, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anterior+segment+ischemia+after+recession+of+various+recti.+An+experimental+study.">Anterior segment ischemia after recession of various recti. An experimental study.</a> Ophthalmology. 94 (10), 1258-1271 (1987).</li><li>Bron, A. J., Easty, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescein+angiography+of+the+globe+and+anterior+segment.">Fluorescein angiography of the globe and anterior segment.</a> Trans Ophthalmol Soc U K. 90, 339-367 (1970).</li><li>Ikegami, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescein+angiography+of+the+anterior+ocular+segment.+Part+1.+Hemodynamics+in+the+anterior+ciliary+vessels+(author's+transl).">Fluorescein angiography of the anterior ocular segment. Part 1. Hemodynamics in the anterior ciliary vessels (author's transl).</a> Nihon Ganka Gakkai Zasshi. 78 (7), 371-385 (1974).</li><li>Banerji, S., 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=LYVE-1,+a+new+homologue+of+the+CD44+glycoprotein,+is+a+lymph-specific+receptor+for+hyaluronan.">LYVE-1, a new homologue of the CD44 glycoprotein, is a lymph-specific receptor for hyaluronan.</a> J Cell Biol. 144 (4), 789-801 (1999).</li><li>Breiteneder-Geleff, S., 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=Angiosarcomas+express+mixed+endothelial+phenotypes+of+blood+and+lymphatic+capillaries:+podoplanin+as+a+specific+marker+for+lymphatic+endothelium.">Angiosarcomas express mixed endothelial phenotypes of blood and lymphatic capillaries: podoplanin as a specific marker for lymphatic endothelium.</a> Am J Pathol. 154 (2), 385-394 (1999).</li></ol>

Laminating the human sclera is a method for performing confocal microscopy on this tissue. A critical step in this process is the use of ethanol instead of formalin for affixing the tissue. In our experience, better results are obtained when using ethanol instead of formalin for fixation. Blunt scalpels aggravate the procedure and should be avoided. Similarly, the drying up of the sclera should be avoided, as it complicates the procedure and reduces the quality of the images.
Regarding the imm...

The sclera is the rigid outer layer that covers the eye, which is made of dense connective tissue. It helps to protect intraocular structures and to maintain intraocular pressure. Thus, the sclera is essential for clear vision. It is devoid of lymphatic vessels 1,2 and thereby forms an outer lymphatic-free border between it and the lymphatic-free inner eye 3-7. It also provides attachment sites for extraocular muscles, thereby sharing anatomical similarities with tendons. Because the sclera mainly consists of dense bundles of type I collagen and has smaller numbers of collagen types III, IV, V, VI, VIII 8,9 and elastin 10,11, this tissue is not easy to use for immunohistochemistry.
Anatomically, the sclera can be separated into three main layers: (1) the superficial vascularized episclera, found underneath the conjunctiva and tenon&#39;s capsule and towards the sides and the back of the eye facing the orbit; (2) the scleral stroma, the main part of the sclera; and (3) the lamina fusca, which is a thin, pigmented layer located directly above the uvea. Our anatomical knowledge about the sclera stems mainly from the first half of the 20th century. At that time, researchers studied the anatomy of vasculature mainly by using India ink injections 12 and vascular casting 13-15. Later, it was researched in angiographic studies 16-19.
Since that time, older techniques have been improved and new ones have been developed that have allowed us to supplement previous anatomical knowledge. For example, it has only been about one decade since we have had such reliable lymphatic markers as lymphatic vascular endothelium specific hyaluronan receptor-1 (LYVE1) 20 or podoplanin 21. Confocal microscopy offers new possibilities for studying the anatomical features of the different tissues of the eye. It allows for multiple stains to be used for differentiating markers of cells or for the localization of cells in relation to blood vessels and other anatomical structures. It provides an overview when the sample is of a larger size and allows us to scan through a sample when in search of a specific cell type. With Z-Stack technology, confocal microscopy can be used for samples up to 100-200 &#181;m. The sclera differs in thickness between 0.3 mm behind the muscle insertions and 1 mm at the posterior pole 11. Due to both its thickness and opaqueness, the sclera is not suitable for confocal microscopy using traditional methods.
To remedy this, scleral tissues were laminated to allow for their analysis with confocal microscopy. This technology is useful for gaining a better understanding of both physiological and pathological situations in the human sclera.

<table>
	<tbody>
		<tr>
			<td>96% ethanol</td>
			<td>Merck Chemicals, Darmstadt, Germany</td>
			<td>P075.4</td>
			<td></td>
		</tr>
		<tr>
			<td>binocular stereo microscope&#160;</td>
			<td>Motic, Hongkong, China</td>
			<td>n.a</td>
			<td></td>
		</tr>
		<tr>
			<td>26G needles&#160;</td>
			<td>Terumo, Leuven, Belgium</td>
			<td>303800</td>
			<td></td>
		</tr>
		<tr>
			<td>15.5mm trepan</td>
			<td>Geuder, Heidelberg, Germany</td>
			<td>n.a</td>
			<td></td>
		</tr>
		<tr>
			<td>no.10 scalpel&#160;</td>
			<td>Feather, pfm medical, Osaka, Japan</td>
			<td>2E+08</td>
			<td></td>
		</tr>
		<tr>
			<td>ophthalmic scalpel micro feather&#160;</td>
			<td>Feather, pfm medical, Osaka, Japan</td>
			<td colspan="2">no. 7657BR</td>
		</tr>
		<tr>
			<td>CD 31 antibody (monoclonal mouse anti human)</td>
			<td>Dako, USA</td>
			<td>IR610</td>
			<td></td>
		</tr>
		<tr>
			<td>LYVE1 antibody&#160; (polyclonal rabbit anti human)</td>
			<td>Zytomed, Germany</td>
			<td colspan="2">RBK014-05</td>
		</tr>
		<tr>
			<td>goat anti mouse FITC antibody</td>
			<td>Sigma Aldrich, Steinheim, Germany</td>
			<td>F0257</td>
			<td></td>
		</tr>
		<tr>
			<td>goat anti rabbit Cy3 antibody</td>
			<td>Dianova, Germany</td>
			<td colspan="2">111-165-003</td>
		</tr>
		<tr>
			<td>Goat Serum normal</td>
			<td>Dako, Glostrup, Denmark</td>
			<td colspan="2">X090710-8</td>
		</tr>
		<tr>
			<td>DAPI</td>
			<td>Carl Roth GmbH, Karlsruhe, Germany</td>
			<td>6335.1</td>
			<td></td>
		</tr>
		<tr>
			<td>microscope slides&#160;</td>
			<td>Engelbrecht, Ederm&#252;nde, Germany</td>
			<td colspan="2">WC7695002</td>
		</tr>
		<tr>
			<td>Coverslips 24x24mm</td>
			<td>Th. Gayer, Lohmar, Germany</td>
			<td>7695026</td>
			<td></td>
		</tr>
		<tr>
			<td>DAKO fluorescent mounting medium&#160;</td>
			<td>DAKO, USA</td>
			<td>S3023</td>
			<td></td>
		</tr>
		<tr>
			<td>LSM Meta 510 confocal microscopy&#160;</td>
			<td>Carl Zeiss AG, Jena, Germany</td>
			<td>n.a</td>
			<td></td>
		</tr>
	</tbody>
</table>

using a laminating technique to perform confocal microscopy of the human sclera

The sclera is a dense connective tissue that covers and protects the eye. It mainly consists of dense collagen bundles (types I, III, IV, V, VI, and VII). Due to its autofluorescence, opaqueness, and thickness, it has not been found suitable for confocal microscopy. An alternative approach to the one presented here, which uses formalin-fixed sclera embedded in paraffin for immunohistochemistry, has technical challenges, especially when preheating the tissue for antigen retrieval. Since the sclera is relatively poor in both cells and vessels, the use of larger tissue samples was explored to help prevent overlooking cells and to understand their localization in relation to vessels and other anatomical sites. To allow for the analysis of larger tissue samples under the confocal microscope, a laminating technique was performed to create thin layers from the sclera. Following the analysis of results of CD31 blood vessels and lymphatic vessel endothelial hyaluronan receptor 1 (LYVE1) positive cells, for which approval for scientific examination was obtained, the advantages and limitations of this method are discussed.

In the representative experiments performed here, there are demonstrable benefits derived from the use of this particular laminating technique. The first experiment illustrates the diverse network of the episcleral blood vessel plexus in three representative pictures (Figure 3). The vessels are positive for CD31.
The second experiment shows immune cells, in particular LYVE1 + cells of the episclera and their rel...

Watch this Scientific Journal Video about Using a Laminating Technique to Perform Confocal Microscopy of the Human Sclera at JoVE.com

Using a Laminating Technique to Perform Confocal Microscopy of the Human Sclera

Human sclera tissue is mainly collagen; therefore, it is not easily usable for immunohistochemistry. To achieve the goal of performing immunohistochemistry for confocal microscopy of scleral tissue, a laminating technique was used.


The sclera is a dense connective tissue that covers and protects the eye. It mainly consists of dense collagen bundles (types I, III, IV, V, VI, and ...

The overall goal of this methodology, is to perform confocal microscopy of the human sclera. This method can help to answer key questions in the ophthalmic field. Such as immune cell distribution and vascular status in the healthy, and the pathological conditions in the Sclera.The main advantage of this technique is that it allows for the confocal imaging of dense connective tissue. Demonstrating the procedure will be Stefan Kremers, a grad student from our laboratory. To begin, prepare 96 percent Ethanol and PBS in individual tubes.Then prepare 100 micro-liters per sample of the primary antibodies in the recommended dilution of PBS containing two percent BSA, and keep all solutions on ice. Arrange clean instruments, including one to two Colibri forceps, straight micro-dissecting scissors, curved scissors, a number 10 scalpel, or ophthalmic scalpel micro feather, four 26 gauge needles, and a swab. Wrap aluminum foil around a polystyrene plate, or prepare a cork plate to affix the tissue.After producing an anteriorly opened bulb according to the text protocol, place the Sclera on a swab with the open part facing up. Then use colibri forceps to remove the retina, and the pigmented uveal layers from the inner sclera until the sclera is free of these layers. Next use curved scissors if necessary to remove the retina and uvea from the papilla.Then remove the remaining conjunctiva, extra-ovular muscles, and tenons capsule from the superficial sclera. Now using colibri forceps to gently hold the tissue, with straight scissors cut approximately two square centimeter sized scleral samples from different locations on the tissue, avoiding repeated grabbing with the forceps which will make the area unsuitable for confocal microscopy. Place the samples in 1.5 milliliter tubes, add 1.5 milliliters of 96 percent ethanol, and incubate for 15 minutes to fix the tissue.Then after removing the ethanol, use 1.5 milliliters of PBS to wash the samples three times for five minutes each while shaking. Next, transfer the samples to 1.5 milliliters of PBS with five percent BSA, and incubate at room temperature for two hours which will induce swelling of the samples, to help with laminating and prevent nonspecific binding. When the samples have swelled, under a stereo-binocular microscope use 26 gauge needles that have been bent at the edges to affix the posterior scleral samples to the foil wrapped polystyrene membrane, or cork plate.Then to laminate the full thickness samples use colibri forceps to horizontally hold the anterior edge of the scleral tissue. With a number 10 scalpel, carefully cut as thin a layer as possible of the superficial sclera, from the underlying layer. To prevent the tissue from drying out pipette 50 micro-liters of PBS onto the layers.Then after the layers have been cut place them in 100 micro-liters of PBS in a 96 well plate, and use a waterproof marker to label both the orientation and the layer. Continue to isolate layers and transfer to the 96 well plate until the tissue is fully laminated. To carry out Immunohistochemistry, remove the medium from the 96 well plate by holding the pipette against the wall of each well and aspirating the fluid.Then add 100 micro-liters of the primary antibodies diluted one to 100 in PBS with two percent BSA to the appropriate wells, and incubate at four degrees Celsius overnight. The next day use 200 to 300 micro-liters of PBS to wash the samples on a shaker three times for five minutes each. If needed, use another primary antibody and incubate again overnight at four degrees Celsius.Then add 100 micro-liters of the corresponding secondary antibodies, diluted one to 300 in PBS with two percent goat serum, and incubate in the dark at room temperature for one to two hours. After the incubation, use 200 to 300 micro-liters of PBS to rinse the samples again on the shaker three times for five minutes each. Then add 100 micro-liters of a one to 2000 dilution of DAPI to each well and incubate in the dark at room temperature.Before using 200 to 300 micro-liters of PBS to wash the samples two times. Transfer the samples onto microscope slides under the stereo-binocular microscope to make sure the sample is lying flat on the slide, and add one to two drops of fluorescent mounting medium. Then place a cover slip on top and use transparent nail polish to seal the edges.Store in the dark at four degrees Celsius for later use or examine directly by confocal microscopy. To verify the thickness of the samples take z-stacks as the thickness differs equatorially and posteriorly depending on the scleral location. These images show the diverse network of the blood vessel plexis in laminated human sclera derived from the anterior and posterior episclera.The blood vessels are positive for CD31 as shown in green. In this figure, LYVE1 positive immune cells of the episclera and their relationship to the CD31 positive blood vessels are illustrated. The z-stack series was taken at 10x magnification to examine the three dimensional relationships of blood vessels and immune cells.As shown here the extra-ocular muscles enclosed within the sclera can also be analysed for the presence of blood vessels or immune cells, using the markers CD31 and LYVE1 respectively. Once mastered the laminating technique can be done in less than one hour if it is performed properly. While attempting this procedure it is important to remember to prevent the tissue from drying out.Don't forget that working with human tissue can be potentially infectious and precautions such as microbiological and virological diagnostics should always be taken beforehand.

using-laminating-technique-to-perform-confocal-microscopy-human

Research

JoVE Journal

Medicine

Corneal Confocal Microscopy: A Novel Non-invasive Technique to Quantify Small Fibre Pathology in Peripheral Neuropathies

The accurate quantification of peripheral neuropathy is important to define at risk patients, anticipate deterioration, and assess new therapies. Conventional methods assess neurological deficits and electrophysiology and quantitative sensory testing quantifies functional alterations to detect neuropathy. However, the earliest damage appears to be to the small fibres and yet these tests primarily assess large fibre dysfunction and have a limited ability to demonstrate regeneration and repair. The only techniques which allow a direct examination of unmyelinated nerve fibre damage and repair are sural nerve biopsy with electron microscopy and skin-punch biopsy. However, both are invasive procedures and require lengthy laboratory procedures and considerable expertise. Corneal Confocal microscopy is a non-invasive clinical technique which provides in-vivo imaging of corneal nerve fibres. We have demonstrated early nerve damage, which precedes loss of intraepidermal nerve fibres in skin biopsies together with stratification of neuropathic severity and repair following pancreas transplantation in diabetic patients. We have also demonstrated nerve damage in idiopathic small fibre neuropathy and Fabry's disease.

Corneal Confocal microscopy is a non-invasive clinical technique which may be used to quantify C fibre damage to diagnose and stratify patients with increasing neuropathic severity.

The accurate quantification of peripheral neuropathy is important to define at risk patients, anticipate deterioration, and assess new therapies. ...

Utilizing Transcranial Magnetic Stimulation to Study the Human Neuromuscular System

Transcranial magnetic stimulation (TMS) has been in use for more than 20 years 1, and has grown exponentially in popularity over the past decade. While the use of TMS has expanded to the study of many systems and processes during this time, the original application and perhaps one of the most common uses of TMS involves studying the physiology, plasticity and function of the human neuromuscular system. Single pulse TMS applied to the motor cortex excites pyramidal neurons transsynaptically 2 (Figure 1) and results in a measurable electromyographic response that can be used to study and evaluate the integrity and excitability of the corticospinal tract in humans 3. Additionally, recent advances in magnetic stimulation now allows for partitioning of cortical versus spinal excitability 4,5. For example, paired-pulse TMS can be used to assess intracortical facilitatory and inhibitory properties by combining a conditioning stimulus and a test stimulus at different interstimulus intervals 3,4,6-8. In this video article we will demonstrate the methodological and technical aspects of these techniques. Specifically, we will demonstrate single-pulse and paired-pulse TMS techniques as applied to the flexor carpi radialis (FCR) muscle as well as the erector spinae (ES) musculature. Our laboratory studies the FCR muscle as it is of interest to our research on the effects of wrist-hand cast immobilization on reduced muscle performance6,9, and we study the ES muscles due to these muscles clinical relevance as it relates to low back pain8. With this stated, we should note that TMS has been used to study many muscles of the hand, arm and legs, and should iterate that our demonstrations in the FCR and ES muscle groups are only selected examples of TMS being used to study the human neuromuscular system.

Transcranial magnetic stimulation (TMS) is a non-invasive tool to gain insight on the physiology and function of the human nervous system. Here, we present our TMS techniques to study cortical excitability of the upper limb and lumbar musculature.

Transcranial magnetic stimulation (TMS) has been in use for more than 20 years 1, and has grown exponentially in popularity over the past decade.  While ...

Probe-based Confocal Laser Endomicroscopy of the Urinary Tract: The Technique

Probe-based confocal laser endomicroscopy (CLE) is an emerging optical imaging technology that enables real-time in vivo microscopy of mucosal surfaces during standard endoscopy. With applications currently in the respiratory1 and gastrointestinal tracts,2-6 CLE has also been explored in the urinary tract for bladder cancer diagnosis.7-10 Cellular morphology and tissue microarchitecture can be resolved with micron scale resolution in real time, in addition to dynamic imaging of the normal and pathological vasculature.7
The probe-based CLE system (Cellvizio, Mauna Kea Technologies, France) consists of a reusable fiberoptic imaging probe coupled to a 488 nm laser scanning unit. The imaging probe is inserted in the working channels of standard flexible and rigid endoscopes. An endoscope-based CLE system (Optiscan, Australia), in which the confocal endomicroscopy functionality is integrated onto the endoscope, is also used in the gastrointestinal tract. Given the larger scope diameter, however, application in the urinary tract is currently limited to ex vivo use.11 Confocal image acquisition is done through direct contact of the imaging probe with the target tissue and recorded as video sequences. As in the gastrointestinal tract, endomicroscopy of the urinary tract requires an exogenenous contrast agent&mdash;most commonly fluorescein, which can be administered intravenously or intravesically. Intravesical administration is a well-established method to introduce pharmacological agents locally with minimal systemic toxicity that is unique to the urinary tract. Fluorescein rapidly stains the extracellular matrix and has an established safety profile.12 Imaging probes of various diameters enable compatibility with different caliber endoscopes. To date, 1.4 and 2.6 mm probes have been evaluated with flexible and rigid cystoscopy.10 Recent availability of a &lt; 1 mm imaging probe13 opens up the possibility of CLE in the upper urinary tract during ureteroscopy. Fluorescence cystoscopy (i.e. photodynamic diagnosis) and narrow band imaging are additional endoscope-based optical imaging modalities14 that can be combined with CLE to achieve multimodal imaging of the urinary tract. In the future, CLE may be coupled with molecular contrast agents such as fluorescently labeled peptides15 and antibodies for endoscopic imaging of disease processes with molecular specificity.

Probe-based confocal laser endomicroscopy enables real-time microscopy of the human urinary tract during cystoscopy, providing dynamic, intravital imaging of pathological states such as bladder cancer with cellular resolution. Endomicroscopy may augment the diagnostic accuracy of standard white light endoscopy and provide intraoperative image guidance to improve surgical resection.

Probe-based  confocal laser endomicroscopy (CLE) is an emerging optical imaging technology  that enables real-time in vivo microscopy of mucosal surfaces ...

Excitotoxic Stimulation of Brain Microslices as an In vitro Model of Stroke

Examining molecular mechanisms involved in neuropathological conditions, such as ischemic stroke, can be difficult when using whole animal systems. As such, primary or &#39;neuronal-like&#39; cell culture systems are commonly utilized. While&#160;these systems are relatively easy to work with, and are useful model systems in which various functional outcomes (such as cell death) can be readily quantified, the examined outcomes and pathways in cultured immature neurons (such as excitotoxicity-mediated cell death pathways) are not necessarily the same as those observed in mature brain, or in intact tissue. Therefore, there is the need to develop models in which cellular mechanisms in mature neural tissue can be examined. We have developed an in vitro technique that can be used to investigate a variety of molecular pathways in intact nervous tissue. The technique described herein utilizes rat cortical tissue, but this technique can be adapted to use tissue from a variety of species (such as mouse, rabbit, guinea pig, and chicken) or brain regions (for example, hippocampus, striatum, etc.). Additionally, a variety of stimulations/treatments can be used (for example, excitotoxic, administration of inhibitors, etc.). In conclusion, the brain slice model described herein can be used to examine a variety of molecular mechanisms involved in excitotoxicity-mediated brain injury.

Excitotoxic Stimulation of Brain Microslices as an In vitro Model of Stroke

We have developed a brain slice model which can be used to examine molecular mechanisms involved in excitotoxicity-mediated brain injury.&#160;This technique generates viable mature brain tissue and reduces animal numbers required for experimentation, whilst keeping the neuronal circuitry, cellular interactions, and postsynaptic compartments partly intact.

Examining molecular mechanisms involved in neuropathological conditions, such as ischemic stroke, can be difficult when using whole animal systems. As ...

Human Skeletal Muscle Biopsy Procedures Using the Modified Bergstr&#246;m Technique

The percutaneous biopsy technique enables researchers and clinicians to collect skeletal muscle tissue samples. The technique is safe and highly effective. This video describes the percutaneous biopsy technique using a modified Bergstr&#246;m needle to obtain skeletal muscle tissue samples from the vastus lateralis of human subjects. The Bergstr&#246;m needle consists of an outer cannula with a small opening (&#8216;window&#8217;) at the side of the tip and an inner trocar with a cutting blade at the distal end. Under local anesthesia and aseptic conditions, the needle is advanced into the skeletal muscle through an incision in the skin, subcutaneous tissue, and fascia. Next, suction is applied to the inner trocar, the outer trocar is pulled back, skeletal muscle tissue is drawn into the window of the outer cannula by the suction, and the inner trocar is rapidly closed, thus cutting or clipping the skeletal muscle tissue sample. The needle is rotated 90&#176;&#160;and another cut is made. This process may be repeated three more times. This multiple cutting technique typically produces a sample of 100-200 mg or more in healthy subjects and can be done immediately before, during, and after a bout of exercise or other intervention. Following post-biopsy dressing of the incision site, subjects typically resume their activities of daily living right away and can fully participate in vigorous physical activity within 48-72 hr. Subjects should avoid heavy resistance exercise for 48 hr to reduce the risk of herniation of the muscle through the incision in the fascia.

Human Skeletal Muscle Biopsy Procedures Using the Modified Bergstr&amp;#246;m Technique

The purpose of this video is to present the modified Bergstr&#246;m skeletal muscle biopsy technique on human subjects.

The percutaneous biopsy technique enables researchers and clinicians to collect skeletal muscle tissue samples. The technique is safe and highly ...

Development of an Algorithm to Perform a Comprehensive Study of Autonomic Dysreflexia in Animals with High Spinal Cord Injury Using a Telemetry Device

Spinal cord injury (SCI) is a debilitating neurological condition characterized by somatic and autonomic dysfunctions. In particular, SCI above the mid-thoracic level can lead to a potentially life-threatening hypertensive condition called autonomic dysreflexia (AD) that is often triggered by noxious or non-noxious somatic or visceral stimuli below the level of injury. One of the most common triggers of AD is the distension of pelvic viscera, such as during bladder and bowel distension or evacuation. This protocol presents a novel pattern recognition algorithm developed for a JAVA platform software to study the fluctuations of cardiovascular parameters as well as the number, severity and duration of spontaneously occurring AD events. The software is able to apply a pattern recognition algorithm on hemodynamic data such as systolic blood pressure (SBP) and heart rate (HR) extracted from telemetry recordings of conscious and unrestrained animals before and after thoracic (T3) complete transection. With this software, hemodynamic parameters and episodes of AD are able to be detected and analyzed with minimal experimenter bias.

The catheter of a telemetry device is implanted into the abdominal aorta in order to continuously collect beat-by-beat hemodynamic data from animals pre and post-high thoracic spinal cord transection. A novel JAVA software was employed to analyze hemodynamic parameters as well as frequency and intensity of spontaneous episodes of autonomic dysreflexia.

Spinal cord injury (SCI) is a debilitating neurological condition characterized by somatic and autonomic dysfunctions. In particular, SCI above the ...

Topical Airway Anesthesia for Awake-endoscopic Intubation Using the Spray-as-you-go Technique with High Oxygen Flow

A patient&#39;s willingness to cooperate is an absolute precondition for successful awake intubation of the trachea. Whilst drug-sedation of patients can jeopardize their spontaneous breathing, topical anesthesia of the airway is a popular technique. The spray-as-you-go technique represents one of the simplest opportunities to anesthetize the airway mucosa. The application of local anesthetic through the working channel of the flexible endoscope is a widespread practice for anesthetists as well as pulmonologists. There is neither need for additional devices nor special training as a pre-requisite to perform this technique. However, a known clinical problem is the coughing and gagging reflex that may occur when the liquid anesthetic strikes the airway mucosa and other sensitive structures like the vocal cords. This can be avoided by the use of oxygen applied through the working channel with the aim of fogging the local anesthetic into finer particles. Furthermore, the oxygen flow provides a higher oxygen supply and contributes to a better view, dispersing mucus secretions and blood away from the lens. Using an atomizer with a high oxygen flow of 10 L/min we maximized these benefits, caused less coughing and had more satisfied and therefore cooperative patients. Possible, but very rare complications of using oxygen flow including gastric insufflation, organ rupture or barotrauma did not arise. We attribute the complication-free use of high oxygen flow to the design of the set, which permits flow and pressure release.

The topical anesthetic lidocaine was atomized using a high oxygen flow through the working channel of a flexible intubating endoscope to achieve topical airway anesthesia for awake endotracheal intubation. We prefer this modified spray-as-you-go technique for endoscopic intubation to classical bolus application because of higher patient satisfaction and better compliance.

A patient&#39;s willingness to cooperate is an absolute precondition for successful awake intubation of the trachea. Whilst drug-sedation of patients can ...

Second Harmonic Generation Signals in Rabbit Sclera As a Tool for Evaluation of Therapeutic Tissue Cross-linking (TXL) for Myopia

Methods to strengthen tissue by introducing chemical bonds (non-enzymatic cross-linking) into structural proteins (fibrillar collagens) for therapy include photochemical cross-linking and tissue cross-linking (TXL) methods. Such methods for inducing mechanical tissue property changes are being employed to the cornea in corneal thinning (mechanically weakened) disorders such as keratoconus as well as the sclera in progressive myopia, where thinning and weakening of the posterior sclera occurs and likely contributes to axial elongation. The primary target proteins for such tissue strengthening are fibrillar collagens which constitute the great majority of dry weight proteins in the cornea and sclera. Fortuitously, fibrillar collagens are the main source of second harmonic generation signals in the tissue extracellular space. Therefore, modifications of the collagen proteins, such as those induced through cross-linking therapies, could potentially be detected and quantitated through the use of second harmonic generation microscopy (SHGM). Monitoring SHGM signals through the use of a laser scanning microscopy system coupled with an infrared excitation light source is an exciting modern imaging method that is enjoying widespread usage in the biomedical sciences. Thus, the present study was undertaken in order to evaluate the use of SHGM microscopy as a means to measure induced cross-linking effects in ex vivo rabbit sclera, following an injection of a chemical cross-linking agent into the sub-Tenon&#39;s space (sT), an injection approach that is standard practice for causing ocular anesthesia during ophthalmologic clinical procedures. The chemical cross-linking agent, sodium hydroxymethylglycinate (SMG), is from a class of cosmetic preservatives known as formaldehyde releasing agents (FARs). Scleral changes following reaction with SMG resulted in increases in SHG signals and correlated with shifts in thermal denaturation temperature, a standard method for evaluating induced tissue cross-linking effects.

Second Harmonic Generation Signals in Rabbit Sclera As a Tool for Evaluation of Therapeutic Tissue Cross-linking TXL for Myopia

This protocol describes techniques for evaluating chemical cross-linking of the rabbit sclera using&#160;second harmonic generation imaging and differential scanning calorimetry.

Methods to strengthen tissue by introducing chemical bonds (non-enzymatic cross-linking) into structural proteins (fibrillar collagens) for therapy ...

Immunofluorescence Labelling of Human and Murine Neutrophil Extracellular Traps in Paraffin-Embedded Tissue

Neutrophil granulocytes, also called polymorphonuclear leukocytes (PMN) due to their lobulated nucleus, are the most abundant type of leukocytes. They mature in the bone marrow and are released into the peripheral blood, where they circulate for about 6&#8722;8 h; however, in tissue, they can survive for days. By diapedesis through the endothelium, they leave the blood stream, enter tissues, and migrate towards the site of an infection following chemotactic gradients.&#160;Neutrophils can combat invading microorganisms by phagocytosis,&#160;degranulation, and generation of neutrophil extracellular traps (NETs). This protocol will help to detect NETs in paraffin-embedded tissue. NETs are the result of a process called NETosis, which leads to the release of nuclear, granular, and cytoplasmic components either from living (vital NETosis) or dying (suicidal NETosis) neutrophils. In vitro, NETs form cloud-like structures, which occupy a space several times larger than that of the cells from which they descended. The backbone of NETs is chromatin, to which a selection of proteins and peptides originating from granules and cytoplasm are bound. Thereby, a high local concentration of toxic compounds is maintained so that NETs can capture and inactivate a variety of pathogens including bacteria, fungi, viruses, and parasites, while diffusion of the highly active NET components leading to damage in neighboring tissue is limited. Nevertheless, in recent years it has become apparent that NETs, if generated in abundance or cleared insufficiently, do have pathological potential ranging from autoimmune diseases to cancer. Thus, detection of NETs in tissue samples may have diagnostic significance, and the detection of NETs in diseased tissue can influence the treatment of patients. Since paraffin-embedded tissue samples are the standard specimen used for pathological analysis, it was sought to establish a protocol for fluorescent staining of NET components in paraffin-embedded tissue using commercially available antibodies.

Neutrophil extracellular traps (NETs) are three-dimensional structures generated by stimulated neutrophil granulocytes. It has become clear in recent years that NETs are involved in a wide variety of diseases. Detection of NETs in tissue may have diagnostic relevance, so standardized protocols for labelling NET components are required.

Neutrophil granulocytes, also called polymorphonuclear leukocytes (PMN) due to their lobulated nucleus, are the most abundant type of leukocytes. They ...

Characterization of a Novel Human Organotypic Retinal Culture Technique

Previous human organotypic retinal culture (HORC) models have utilized detached retinas; however, without the structural support conferred by retinal pigment epithelium-choroid (RPE-choroid) and sclera, the integrity of the fragile retina can easily be compromised. The aim of this study was to develop a novel HORC model that contains the retina, RPE-choroid and sclera to maintain retinal integrity when culturing retinal explants.
After cutting circumferentially along the limbus to remove iris and lens, four deep incisions were made to flatten the eyecup. In contrast to previous HORC protocols, a trephine was used to cut through not only the retina but also the RPE-choroid and sclera. The resultant triple-layered explants were cultured for 72 h. Hematoxylin and Eosin staining (H&#38;E) was used to assess anatomical structures and retinal explants were further characterized by immunohistochemistry (IHC) for apoptosis, M&#252;ller cell integrity and retinal inflammation. To confirm the possibility of disease induction, explants were exposed to high glucose (HG) and pro-inflammatory cytokines (Cyt), to mimic diabetic retinopathy (DR). The Luminex magnetic bead assay was used to measure DR-related cytokines released into the culture medium.
H&#38;E staining revealed distinct retinal lamellae and compact nuclei in retinal explants with the underlying RPE-choroid and sclera, while retinas without the underlying structures exhibited reduced thickness and severe nuclei loss. IHC results indicated absence of apoptosis and retinal inflammation as well as preserved M&#252;ller cell integrity. The Luminex&#160;assays showed significantly increased secretion of DR-associated pro-inflammatory cytokines in retinal explants exposed to HG + Cyt relative to baseline levels at 24 h.
We successfully developed and characterized a novel HORC protocol in which retinal integrity was preserved without apoptosis or retinal inflammation. Moreover, the induced secretion of DR-associated pro-inflammatory biomarkers when exposing retinal explants to HG + Cyt suggests that this model could be used for clinically translatable retinal disease studies.

This study aims to develop a novel human organotypic retinal culture (HORC) model that prevents compromising retinal integrity during explant handling. This is achieved by culturing the retina with the overlying vitreous and the underlying retinal pigment&#160;epithelium-choroid (RPE-choroid) and sclera.

Previous human organotypic retinal culture (HORC) models have utilized detached retinas; however, without the structural support conferred by retinal ...