Name: continuous iv infusion is the choice treatment route for arginine-vasopressin receptor blocker conivaptan in mice to study stroke-evoked brain edema
Uploaded: 2016-09-01T14:00:00
Description: Watch this Scientific Journal Video about Continuous IV Infusion is the Choice Treatment Route for Arginine-vasopressin Receptor Blocker Conivaptan in Mice to Study Stroke-evoked Brain Edema at JoVE.c

We thank Swedish Medical Center for providing the funding and facilities. We also thank Craig Hospital for the generous use of laboratory space.

Experiments were carried out in accordance with the guidelines of the National Institutes of Health for the care and use of animals in research and were approved by the Swedish Medical Center Animal Care and Use Committee. All procedures were performed with appropriate aseptic techniques. Experimental animals utilized for the study were male, 3 months old, wild type C57 mice with body weight from 25 to 27 g.
1. In Vivo Stroke Induction
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	<li>Pre-coat the Filament with Dental Res...

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R., 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=Etiology+of+stroke+and+choice+of+models.">Etiology of stroke and choice of models.</a> Int J Stroke. 7, 398-406 (2012).</li><li>Vakili, A., Kataoka, H., Plesnila, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+arginine+vasopressin+V1+and+V2+receptors+for+brain+damage+after+transient+focal+cerebral+ischemia.">Role of arginine vasopressin V1 and V2 receptors for brain damage after transient focal cerebral ischemia.</a> J Cereb Blood Flow Metab. 25, 1012-1019 (2005).</li><li>Zeynalov, E., Jones, S. M., Seo, J. W., Snell, L. D., Elliott, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Arginine-Vasopressin+Receptor+Blocker+Conivaptan+Reduces+Brain+Edema+and+Blood-Brain+Barrier+Disruption+after+Experimental+Stroke+in+Mice.">Arginine-Vasopressin Receptor Blocker Conivaptan Reduces Brain Edema and Blood-Brain Barrier Disruption after Experimental Stroke in Mice.</a> PloS one. 10, e0136121 (2015).</li><li>Med Lett Drugs Ther.. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conivaptan+(Vaprisol)+for+hyponatremia.">Conivaptan (Vaprisol) for hyponatremia.</a> The Medical letter on drugs and therapeutics. 48, 51-52 (2006).</li><li>Zhao, X. Y., 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=Effect+of+arginine+vasopressin+on+the+cortex+edema+in+the+ischemic+stroke+of+Mongolian+gerbils.">Effect of arginine vasopressin on the cortex edema in the ischemic stroke of Mongolian gerbils.</a> Neuropeptides. 51, 55-62 (2015).</li><li>Manaenko, A., Chen, H., Kammer, J., Zhang, J. H., Tang, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+Evans+Blue+injection+routes:+Intravenous+versus+intraperitoneal,+for+measurement+of+blood-brain+barrier+in+a+mice+hemorrhage+model.">Comparison Evans Blue injection routes: Intravenous versus intraperitoneal, for measurement of blood-brain barrier in a mice hemorrhage model.</a> J Neurosci Methods. 195, 206-210 (2011).</li><li>Adams, S., Pacharinsak, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+anesthesia+and+analgesia.">Mouse anesthesia and analgesia.</a> Curr Protoc Mouse Biol. 5, 51-63 (2015).</li><li>Zeynalov, E., 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=The+perivascular+pool+of+aquaporin-4+mediates+the+effect+of+osmotherapy+in+postischemic+cerebral+edema.">The perivascular pool of aquaporin-4 mediates the effect of osmotherapy in postischemic cerebral edema.</a> Crit Care Med. 36, 2634-2640 (2008).</li><li>Zeynalov, E., Dore, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low+doses+of+carbon+monoxide+protect+against+experimental+focal+brain+ischemia.">Low doses of carbon monoxide protect against experimental focal brain ischemia.</a> Neurotox Res. 15, 133-137 (2009).</li><li>Zeynalov, E., Nemoto, M., Hurn, P. D., Koehler, R. C., Bhardwaj, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neuroprotective+effect+of+selective+kappa+opioid+receptor+agonist+is+gender+specific+and+linked+to+reduced+neuronal+nitric+oxide.">Neuroprotective effect of selective kappa opioid receptor agonist is gender specific and linked to reduced neuronal nitric oxide.</a> J Cereb Blood Flow Metab. 26, 414-420 (2006).</li><li>Ma, M. C., Qian, H., Ghassemi, F., Zhao, P., Xia, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxygen-sensitive+{delta}-opioid+receptor-regulated+survival+and+death+signals:+novel+insights+into+neuronal+preconditioning+and+protection.">Oxygen-sensitive {delta}-opioid receptor-regulated survival and death signals: novel insights into neuronal preconditioning and protection.</a> J Biol Chem. 280, 16208-16218 (2005).</li><li>Ahmad, M., Zhang, Y., Liu, H., Rose, M. E., Graham, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prolonged+opportunity+for+neuroprotection+in+experimental+stroke+with+selective+blockade+of+cyclooxygenase-2+activity.">Prolonged opportunity for neuroprotection in experimental stroke with selective blockade of cyclooxygenase-2 activity.</a> Brain Res. 1279, 168-173 (2009).</li><li>Meisel, C., 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=Preventive+antibacterial+treatment+improves+the+general+medical+and+neurological+outcome+in+a+mouse+model+of+stroke.">Preventive antibacterial treatment improves the general medical and neurological outcome in a mouse model of stroke.</a> Stroke. 35, 2-6 (2004).</li><li>Miner, N. A., Koehler, J., Greenaway, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intraperitoneal+injection+of+mice.">Intraperitoneal injection of mice.</a> Appl Microbiol. 17, 250-251 (1969).</li><li>Adis International Limited. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conivaptan:+YM+087.">Conivaptan: YM 087.</a> Drugs in R&amp;D. 5, 94-97 (2004).</li><li>Murphy, T., Dhar, R., Diringer, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conivaptan+bolus+dosing+for+the+correction+of+hyponatremia+in+the+neurointensive+care+unit.">Conivaptan bolus dosing for the correction of hyponatremia in the neurointensive care unit.</a> Neurocrit Care. 11, 14-19 (2009).</li><li>Liu, X., Nakayama, S., Amiry-Moghaddam, M., Ottersen, O. P., Bhardwaj, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Arginine-vasopressin+V1+but+not+V2+receptor+antagonism+modulates+infarct+volume,+brain+water+content,+and+aquaporin-4+expression+following+experimental+stroke.">Arginine-vasopressin V1 but not V2 receptor antagonism modulates infarct volume, brain water content, and aquaporin-4 expression following experimental stroke.</a> Neurocrit Care. 12, 124-131 (2010).</li><li>Wallace, B. K., Jelks, K. A., O'Donnell, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ischemia-induced+stimulation+of+cerebral+microvascular+endothelial+cell+Na-K-Cl+cotransport+involves+p38+and+JNK+MAP+kinases.">Ischemia-induced stimulation of cerebral microvascular endothelial cell Na-K-Cl cotransport involves p38 and JNK MAP kinases.</a> Am J Physiol Cell Physiol. 302, C505-C517 (2012).</li><li>O'Donnell, M. E., 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=Intravenous+HOE-642+reduces+brain+edema+and+Na+uptake+in+the+rat+permanent+middle+cerebral+artery+occlusion+model+of+stroke:+evidence+for+participation+of+the+blood-brain+barrier+Na/H+exchanger.">Intravenous HOE-642 reduces brain edema and Na uptake in the rat permanent middle cerebral artery occlusion model of stroke: evidence for participation of the blood-brain barrier Na/H exchanger.</a> J Cereb Blood Flow Metab. 33, 225-234 (2013).</li><li>Walcott, B. P., Kahle, K. T., Simard, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+treatment+targets+for+cerebral+edema.">Novel treatment targets for cerebral edema.</a> Neurotherapeutics. 9, 65-72 (2012).</li><li>Shen, Z., 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=Inhibition+of+G+protein-coupled+receptor+81+(GPR81)+protects+against+ischemic+brain+injury.">Inhibition of G protein-coupled receptor 81 (GPR81) protects against ischemic brain injury.</a> CNS Neurosci Ther. 21, 271-279 (2015).</li></ol>

This study has important value for preclinical stroke research. This study reveals that continuous IV infusion of conivaptan (0.2 mg/day) after experimental stroke in mice efficiently reduces brain edema after 48 hr of treatment. The effect of IP injection of the same dose of conivaptan on brain edema was also investigated. Conivaptan treatment by both IV and IP routes produces aquaresis in mice as indicated by: 1) increase in plasma osmolality slightly above physiological levels; and 2) decrease in urine osmolality due ...

Stroke continues to be an enormous burden for patients and clinicians. Animal stroke models have been used in the laboratory setting for nearly two decades.1 Nevertheless, experimental treatments that work in animals often fail in humans.2 This discrepancy in treatment outcomes may be due to various factors, such as administration routes for drugs used in animal research, drug metabolism and elimination rate, and many other aspects. One of the major complications of stroke, brain edema, is a focus of current research in neuroscience. Mechanisms of brain edema formation involve disturbances in water and electrolyte balance triggered by the arginine-vasopressin (AVP) response to ischemic brain injury.3 Therefore, AVP and its receptors (V1a and V2) are a major focus of research studies of post-ischemic brain edema formation.3
We have developed a methodology to study the effects of mixed arginine-vasopressin (V1a and V2) receptor blocker conivaptan on post-ischemic brain edema in mice.4 Molecular targets of conivaptan5 make the drug a suitable candidate for exploration of its properties in alleviation of brain edema. Furthermore, conivaptan needs to be studied in the context of pathophysiological events of stroke.6 In designing this study, we considered comparing treatment outcomes using two different routes of administration for conivaptan: intravenous (IV)4 and intraperitoneal (IP).7 Effects of the treatments on stroke-induced brain edema were evaluated. Here detailed protocols are described for surgical induction of experimental stroke by middle cerebral artery occlusion (MCAO), and followed by continuous conivaptan treatment using the installation of a jugular IV catheter. After induction of stroke, animals were randomly allocated into the following groups: vehicle or conivaptan (0.2 mg/day) treated IV or IP.

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			<td>Heated Pad</td>
			<td>K&#38;H Manufacturing Inc</td>
			<td>1060</td>
			<td></td>
		</tr>
		<tr>
			<td>Temperature Monitor with Rectal Probe</td>
			<td>Physitemp</td>
			<td>7029</td>
			<td></td>
		</tr>
		<tr>
			<td>Silk Suture Spool, 6-0</td>
			<td>Surgical Specialties Corporation</td>
			<td>SP114</td>
			<td></td>
		</tr>
		<tr>
			<td>Silk Suture on a Needle, 3-0</td>
			<td>Ethicon</td>
			<td>1684G</td>
			<td></td>
		</tr>
		<tr>
			<td>Nylon Suture, 7-0</td>
			<td>Ethicon</td>
			<td>1696G</td>
			<td></td>
		</tr>
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			<td>Dental Resin Polysiloxane with Hardener</td>
			<td>Heraeus Kulzer</td>
			<td>65817930</td>
			<td></td>
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			<td>Microinfusion IV Pump</td>
			<td>Kent Scietific</td>
			<td>GT0897</td>
			<td></td>
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		<tr>
			<td>Swivel 22GA</td>
			<td>Instech</td>
			<td>375/22PS</td>
			<td></td>
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			<td>Laboratory Tubing, 0.94 x 0.51 mm</td>
			<td>Dow Corning</td>
			<td>508-002</td>
			<td></td>
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		<tr>
			<td>Laboratory Tubing, 3.18 x 1.98 mm</td>
			<td>Dow Corning</td>
			<td>508-009</td>
			<td></td>
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continuous iv infusion is the choice treatment route for arginine-vasopressin receptor blocker conivaptan in mice to study stroke-evoked brain edema

Stroke is one of the major causes of morbidity and mortality in the world. Stroke is complicated by brain edema and other pathophysiological events. Among the most important players in the development and evolution of stroke-evoked brain edema is the hormone arginine-vasopressin and its receptors, V1a and V2. Recently, the V1a and V2 receptor blocker conivaptan has been attracting attention as a potential drug to reduce brain edema after stroke. However, animal models which involve conivaptan applications in stroke research need to be modified based on feasible routes of administration. Here the outcomes of 48 hr continuous intravenous (IV) are compared with intraperitoneal (IP) conivaptan treatments after experimental stroke in mice. We developed a protocol in which middle cerebral artery occlusion was combined with catheter installation into the jugular vein for IV treatment of conivaptan (0.2 mg) or vehicle. Different cohorts of animals were treated with 0.2 mg bolus of conivaptan or vehicle IP daily. Experimental stroke-evoked brain edema was evaluated in mice after continuous IV and IP treatments. Comparison of the results revealed that the continuous IV administration of conivaptan alleviates post-ischemic brain edema in mice, unlike the IP administration of conivaptan. We conclude that our model can be used for future studies of conivaptan applications in the context of stroke and brain edema.

Body temperature of the animals was within the physiological range and stable throughout the surgical procedure of stroke induction. Two mice that exhibited NDS lower than 2 immediately after MCAO were excluded from the study.
MCAO in mice produces infarct volume in the ipsilateral hemisphere at 48 hr. Evaluation of the TTC-stained slices shows that about 50% of the hemisphere is affected by infarct after MCAO (Figure 1D...

Watch this Scientific Journal Video about Continuous IV Infusion is the Choice Treatment Route for Arginine-vasopressin Receptor Blocker Conivaptan in Mice to Study Stroke-evoked Brain Edema at JoVE.c

Continuous IV Infusion is the Choice Treatment Route for Arginine-vasopressin Receptor Blocker Conivaptan in Mice to Study Stroke-evoked Brain Edema

Our studies have revealed that the beneficial effects of conivaptan are dependent on the method of delivery after experimental stroke in mice. We have developed a research protocol for delivery of the receptor blocker via IV catheter on stroke-evoked brain edema formation in mice.

Stroke is one of the major causes of morbidity and mortality in the world. Stroke is complicated by brain edema and other pathophysiological events. Among ...

The overall goal of this pre-clinical study, is to create a successful mouse model of Conivaptan administration after stroke, to help improve the design of future research studies in the stroke field. This method can help answer key questions in the stroke research field, such as, what is the importance of the delivery route to the beneficial effects of Conivaptan on stroke recovery in mice. The main advantage of this technique, is that it will assist researchers in the modelling studies of Conivaptan and it's effects on stroke-evoked brain edema.At least two hours before the surgery, cut a 12 millimeter piece of filament from a 7-0 nylon suture, then mix two parts dental resin with one part hardener, and quickly dip the filament into the mixture, until approximately four millimeters of the filament have been coated. Immediately verify that the filament tip is covered with a smooth coat of dental resin. Then, air-dry the filament for two hours.When the resin is ready, place an anesthetized mouse onto a heating pad on the operating table, and confirm a lack of response to toe-pinch. Remove the hair on the front and back of the neck with clippers, spray the neck with rubbing alcohol, and apply ointment to both eyes. To continuously monitor body temperature during the surgery, use a rectal temperature probe connected to a digital display.Place the mouse in the supine position under a dissecting microscope, and if necessary, position a piece of rolled gauze underneath the neck to arch it. Then disinfect the neck with a Povidone Iodine 10%scrub solution. Then, cover the animal with a sterile drape, and use a size 10 surgical blade to make a mid-line incision along the neck.Using a 6-0 silk suture, temporarily ligate the left common carotid artery, and follow this with a tie on the left external carotid artery. Place a microvascular clip on the internal carotid artery, and use microvascular scissors to cut a small hole on the external carotid artery. After inserting the dental resin-coated filament into the opening, advance the filament cephalically while removing the clip until resistance is felt.Place a temporary tie onto the internal carotid artery to secure the filament in position, and close the skin with a silk suture. Then infiltrate the wound on the front of the neck with 0.2 millimeters of 0.5%Bupivacaine and transfer the mouse to a recovery chamber with monitoring until sternal recumbance is maintained. For Neurological Deficit Scoring, lift the mouse by the tail, and place the animal on a flat surface for two to three minutes.Score the animal's behavior according to the text, excluding mice that exhibit a Neurological Deficit Score lower than two, due to an insufficient occlusion of the middle cerebral artery. To remove the filament, re-sterilize the incision with a 10%Povidone Iodine scrub solution, and cut and remove the suture to re-open the surgical wound. Then, under a dissecting microscope, place a microvascular clip on the internal carotid artery, and untie the internal carotid arterial suture.Hold the clip open to slide out the filament. Then immediately close the clip again, and suture the external carotid artery proximal to the cut. When the external carotid artery ligature is secure, remove the clip and untie the suture around the common carotid artery to restore the blood flow to the brain.Immediately after removing the common carotid artery suture, disinfect the back of the neck with a 10%Povidone Iodine scrub solution, and use a size 10 surgical scalpel blade to make a one centimeter incision. Then re-sterilize the front of the neck, and re-open the surgical wound. Now tunnel a piece of 0.94 millimeter outer-diameter tubing, nested within a piece of 3.18 millimeter outer-diameter tubing under the skin of the animal from the back to the front of the neck, and exteriorize the tubing when it reaches the front incision.Remove the subcutaneous adipose tissue from the left side of the front of the neck about one centimeter laterally from the mid-line. Then locate the left jugular vein under the dissecting microscope, and place two ties along the vein 5 millimeters apart, slightly stretching the vessel. Next, use microvascular scissors to make a small hole on the jugular vein between the two ties, and insert the tip of the inner tubing five millimeters deep caudally toward the heart.Secure the tubing with both ties to the jugular vein, and use a 3-0 silk suture to close the skin on the front of the neck. Then secure the tubing to the skin on the back of the neck with a suture and connect the tubing to a micro-infusion intravenous pump through a swivel. Infiltrate the skin incisions on the front and the back of the neck with 0.2 millimeters of 0.5%Bupivacaine to prevent post-operative pain, and allow the animal to awaken in the recovery chamber with monitoring.When the animal is recumbent, set the infusion rate for a continuous 48 hour intravenous treatment of Conivaptan or vehicle, at 1.5 millimeters per kilogram per hour, and start the infusion. Alternatively, administer 0.2 milligrams of Conivaptan and 1.44 milliliters of 5%Dextrose twice intraperitoneally, daily for two days, followed by a brief observation of the animals after each injection. Middle cerebral arterial occlusion in mice, produces an infarct volume in the ipsilateral hemisphere at 48 hours with approximately 50%of the hemisphere affected as visualized by tetrazolium chloride staining.The evaluation of the brain water content at 48 hours after a 60 minute middle cerebral arterial occlusion induction, reveals that intravenous Conivaptan administration significantly reduces the brain edema, in both the ipsilateral and contralateral hemispheres. In contrast, daily intraperitoneal Conivaptan treatment by a 0.2 millimeters bolus fails to produce similar positive effects on the stroke-evoked brain edema. Once mastered, this technique can be completed in two hours, if it is performed properly.While attempting this procedure, it's important to remember to avoid excessive blood loss in the experimental animal because it can affect your study result and lead to increased mortality. Following this procedure, other studies like evaluating the blood brain barrier disruption can be performed to answer additional questions about the involvement of inflammation in post-ischemic brain edema. After the development, this technique paved the way for researchers in the field of neuroscience, to explore the importance of route of drug administration for clinical studies.After watching this video, you should have a good understanding of how to surgically create ischemic conditions in mice and stow an intravenous catheter into the jugular vein and administer Conivaptan by continuous IV infusion in mice. Don't forget that working with live animals can be extremely hazardous and that precautions such as wearing surgical gloves and masks should always be taken while performing this procedure.

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Research

JoVE Journal

Medicine

The Measurement and Treatment of Suppression in Amblyopia

Amblyopia, a developmental disorder of the visual cortex, is one of the leading causes of visual dysfunction in the working age population. Current estimates put the prevalence of amblyopia at approximately 1-3%1-3, the majority of cases being monocular2. Amblyopia is most frequently caused by ocular misalignment (strabismus), blur induced by unequal refractive error (anisometropia), and in some cases by form deprivation.
Although amblyopia is initially caused by abnormal visual input in infancy, once established, the visual deficit often remains when normal visual input has been restored using surgery and/or refractive correction. This is because amblyopia is the result of abnormal visual cortex development rather than a problem with the amblyopic eye itself4,5 . Amblyopia is characterized by both monocular and binocular deficits6,7 which include impaired visual acuity and poor or absent stereopsis respectively. The visual dysfunction in amblyopia is often associated with a strong suppression of the inputs from the amblyopic eye under binocular viewing conditions8. Recent work has indicated that suppression may play a central role in both the monocular and binocular deficits associated with amblyopia9,10 .
Current clinical tests for suppression tend to verify the presence or absence of suppression rather than giving a quantitative measurement of the degree of suppression. Here we describe a technique for measuring amblyopic suppression with a compact, portable device11,12 . The device consists of a laptop computer connected to a pair of virtual reality goggles. The novelty of the technique lies in the way we present visual stimuli to measure suppression. Stimuli are shown to the amblyopic eye at high contrast while the contrast of the stimuli shown to the non-amblyopic eye are varied. Patients perform a simple signal/noise task that allows for a precise measurement of the strength of excitatory binocular interactions. The contrast offset at which neither eye has a performance advantage is a measure of the "balance point" and is a direct measure of suppression. This technique has been validated psychophysically both in control13,14 and patient6,9,11 populations.
In addition to measuring suppression this technique also forms the basis of a novel form of treatment to decrease suppression over time and improve binocular and often monocular function in adult patients with amblyopia12,15,16 . This new treatment approach can be deployed either on the goggle system described above or on a specially modified iPod touch device15.

Amblyopia is a developmental disorder of the visual cortex that is often accompanied by strong suppression of one eye. We present a new technique for measuring and treating interocular suppression in patients with amblyopia that can be deployed using virtual reality goggles or a portable iPod Touch device.

Amblyopia, a developmental disorder of the visual cortex, is one of the leading causes of visual dysfunction in the working age population. Current ...

Orthotopic Aortic Transplantation in Mice for the Study of Vascular Disease

Vascular procedures involving anastomoses in the mouse are generally thought to be difficult and highly dependent on the skill of the individual surgeon. This is largely true, but there are a number of important principles that can reduce the difficulty of these procedures and enhance reproducibility. Orthotopic aortic transplantation is an excellent procedure in which to learn these principles because it involves only two end-to-end anastomoses, but requires good suturing technique and handling of the vessels for consistent success. This procedure begins with the procurement of a length of abdominal aorta from a donor animal, followed by division of the native aorta in the recipient. The procured aorta is then placed between the divided ends of the recipient aorta and sutured into place using end-to-end anastomoses. To accomplish this objective successfully requires a high degree of concentration, good tools, a steady hand, and an appreciation of how easily the vasculature of a mouse can be damaged, resulting in thrombosis. Learning these important principles is what occupies most of the beginner's time when learning microsurgery in small rodents. Throughout this protocol, we refer to these important points. This model can be used to study vascular disease in a variety of different experimental systems1-8. In the context shown here, it is most often used for the study of post-transplant vascular disease, a common long-term complication of solid organ transplantation in which intimal hyperplasia occurs within the allograft. The primary advantage of the model is that it facilitates quantitative morphometric analyses and the transplanted vessel lies contiguous to the endogenous vessel, which can serve as an additional control9. The technique shown here is most often used for mice weighing 18-25 grams. We have accumulated most of our experience using the C57BL/6J, BALB/cJ, and C3H/HeJ strains.

We describe a technique in which a section of the abdominal aorta from a mouse is transplanted orthotopically to just below the renal arteries in an allogeneic or syngeneic recipient. This technique can be useful in studies in which transplantation of large arteries of uniform size is deemed advantageous.

Vascular procedures involving anastomoses in the mouse are generally thought to be difficult and highly dependent on the skill of the individual surgeon. ...

A Novel High-resolution In vivo Imaging Technique to Study the Dynamic Response of Intracranial Structures to Tumor Growth and Therapeutics

We have successfully integrated previously established Intracranial window (ICW) technology 1-4 with intravital 2-photon confocal microscopy to develop a novel platform that allows for direct long-term visualization of tissue structure changes intracranially. Imaging at a single cell resolution in a real-time fashion provides supplementary dynamic information beyond that provided by standard end-point histological analysis, which looks solely at 'snap-shot' cross sections of tissue.
Establishing this intravital imaging technique in fluorescent chimeric mice, we are able to image four fluorescent channels simultaneously. By incorporating fluorescently labeled cells, such as GFP+ bone marrow, it is possible to track the fate of these cells studying their long-term migration, integration and differentiation within tissue. Further integration of a secondary reporter cell, such as an mCherry glioma tumor line, allows for characterization of cell:cell interactions. Structural changes in the tissue microenvironment can be highlighted through the addition of intra-vital dyes and antibodies, for example CD31 tagged antibodies and Dextran molecules.
Moreover, we describe the combination of our ICW imaging model with a small animal micro-irradiator that provides stereotactic irradiation, creating a platform through which the dynamic tissue changes that occur following the administration of ionizing irradiation can be assessed.
Current limitations of our model include penetrance of the microscope, which is limited to a depth of up to 900 &mu;m from the sub cortical surface, limiting imaging to the dorsal axis of the brain. The presence of the skull bone makes the ICW a more challenging technical procedure, compared to the more established and utilized chamber models currently used to study mammary tissue and fat pads 5-7. In addition, the ICW provides many challenges when optimizing the imaging.

A Novel High-resolution In vivo Imaging Technique to Study the Dynamic Response of Intracranial Structures to Tumor Growth and Therapeutics

We describe a novel in vivo imaging technique that couples fluorescent chimeric mice with intracranial windows and high-resolution 2-photon microscopy. This imaging platform aids studies of dynamic changes in brain tissue and microvasculature, at a single-cell level, following pathological insults and is adaptable to assess intracranial drug delivery and distribution.

We have successfully integrated previously established Intracranial window (ICW) technology 1-4 with intravital 2-photon confocal microscopy to develop a ...

Using Continuous Data Tracking Technology to Study Exercise Adherence in Pulmonary Rehabilitation

Pulmonary rehabilitation (PR) is an important component in the management of respiratory diseases. The effectiveness of PR is dependent upon adherence to exercise training recommendations. The study of exercise adherence is thus a key step towards the optimization of PR programs. To date, mostly indirect measures, such as rates of participation, completion, and attendance, have been used to determine adherence to PR. The purpose of the present protocol is to describe how continuous data tracking technology can be used to measure adherence to a prescribed aerobic training intensity on a second-by-second basis.
In our investigations, adherence has been defined as the percent time spent within a specified target heart rate range. As such, using a combination of hardware and software, heart rate is measured, tracked, and recorded during cycling second-by-second for each participant, for each exercise session. Using statistical software, the data is subsequently extracted and analyzed. The same protocol can be applied to determine adherence to other measures of exercise intensity, such as time spent at a specified wattage, level, or speed on the cycle ergometer. Furthermore, the hardware and software is also available to measure adherence to other modes of training, such as the treadmill, elliptical, stepper, and arm ergometer. The present protocol, therefore, has a vast applicability to directly measure adherence to aerobic exercise.

Pulmonary rehabilitation is widely recognized in the management of respiratory diseases. A key component to successful pulmonary rehabilitation is adherence to the recommended exercise training. The purpose of the present protocol is to describe how continuous data tracking technology can be used to precisely measure adherence to a prescribed aerobic training intensity.

Pulmonary rehabilitation (PR) is an important component in the management of respiratory diseases. The effectiveness of PR is dependent upon adherence to ...

High-throughput Flow Cytometry Cell-based Assay to Detect Antibodies to N-Methyl-D-aspartate Receptor or Dopamine-2 Receptor in Human Serum

Over the recent years, antibodies against surface and conformational proteins involved in neurotransmission have been detected in autoimmune CNS diseases in children and adults. These antibodies have been used to guide diagnosis and treatment. Cell-based assays have improved the detection of antibodies in patient serum. They are based on the surface expression of brain antigens on eukaryotic cells, which are then incubated with diluted patient sera followed by fluorochrome-conjugated secondary antibodies. After washing, secondary antibody binding is then analyzed by flow cytometry. Our group has developed a high-throughput flow cytometry live cell-based assay to reliably detect antibodies against specific neurotransmitter receptors. This flow cytometry method is straight forward, quantitative, efficient, and the use of a high-throughput sampler system allows for large patient cohorts to be easily assayed in a short space of time. Additionally, this cell-based assay can be easily adapted to detect antibodies to many different antigenic targets, both from the central nervous system and periphery. Discovering additional novel antibody biomarkers will enable prompt and accurate diagnosis and improve treatment of immune-mediated disorders.

Over the recent years, live cell-based assays have been used successfully to detect antibodies against surface and conformational antigens. Here, we describe a method using high-throughput flow cytometry enabling the analysis of large cohorts of patients. Detection of novel antibodies will improve diagnosis and treatment of immune-mediated disorders.

Over the recent years, antibodies against surface and conformational proteins involved in neurotransmission have been detected in autoimmune CNS diseases ...

Heterotopic Mucosal Engrafting Procedure for Direct Drug Delivery to the Brain in Mice

Delivery of therapeutics into the brain is impeded by the presence of the blood-brain barrier (BBB) which restricts the passage of polar and high molecular weight compounds from the bloodstream and into brain tissue. Some direct delivery success in humans has been achieved via implantation of transcranial catheters; however this method is highly invasive and associated with numerous complications. A less invasive alternative would be to dose the brain through a surgically implanted, semipermeable membrane such as the nasal mucosa that is used to repair skull base defects following endoscopic transnasal tumor removal surgery in humans. Drug transfer though this membrane would effectively bypass the BBB and diffuse directly into the brain and cerebrospinal fluid. Inspired by this approach, a surgical approach in mice was developed that uses a donor septal mucosal membrane engrafted over an extracranial surgical BBB defect. This model has been shown to effectively allow the passage of high molecular weight compounds into the brain. Since numerous drug candidates are incapable of crossing the BBB, this model is valuable for performing preclinical testing of novel therapies for neurological and psychiatric diseases.

A mouse model of human endoscopic skull base reconstruction has been developed that creates a semipermeable interface between the brain and nose using nasal mucosal grafts. This method allows researchers to study delivery to the central nervous system of high molecular weight therapeutics which are otherwise excluded by the blood-brain barrier when administered systemically.

Delivery of therapeutics into the brain is impeded by the presence of the blood-brain barrier (BBB) which restricts the passage of polar and high ...

Slow-release Drug Delivery through Elvax 40W to the Rat Retina: Implications for the Treatment of Chronic Conditions

Diseases of the retina are difficult to treat as the retina lies deep within the eye. Invasive methods of drug delivery are often needed to treat these diseases. Chronic retinal diseases such as retinal oedema or neovascularization usually require multiple intraocular injections to effectively treat the condition. However, the risks associated with these injections increase with repeated delivery of the drug. Therefore, alternative delivery methods need to be established in order to minimize the risks of reinjection. Several other investigations have developed methods to deliver drugs over extended time, through materials capable of releasing chemicals slowly into the eye. In this investigation, we outline the use of Elvax 40W, a copolymer resin, to act as a vehicle for drug delivery to the adult rat retina. The resin is made and loaded with the drug. The drug-resin complex is then implanted into the vitreous cavity, where it will slowly release the drug over time. This method was tested using 2-amino-4-phosphonobutyrate (APB), a glutamate analogue that blocks the light response of the retina. It was demonstrated that the APB was slowly released from the resin, and was able to block the retinal response by 7 days after implantation. This indicates that slow-release drug delivery using this copolymer resin is effective for treating the retina, and could be used therapeutically with further testing.

This paper details how Elvax 40W can be used as a slow-release method for drug delivery to the adult rat retina. The protocol for preparing, loading, and delivering the drug-resin complex to the eye is described.

Diseases of the retina are difficult to treat as the retina lies deep within the eye. Invasive methods of drug delivery are often needed to treat these ...

Using Saccadometry with Deep Brain Stimulation to Study Normal and Pathological Brain Function

The oculomotor system involves a large number of brain areas including parts of the basal ganglia, and various neurodegenerative diseases including Parkinson's and Huntington's can disrupt it. People with Parkinson's disease, for example, tend to have increased saccadic latencies. Consequently, the quantitative measurement of saccadic eye movements has received considerable attention as a potential biomarker for neurodegenerative conditions. A lot more can be learned about the brain in both health and disease by observing what happens to eye movements when the function of specific brain areas is perturbed. Deep brain stimulation is a surgical intervention used for the management of a range of neurological conditions including Parkinson's disease, in which stimulating electrodes are placed in specific brain areas including several sites in the basal ganglia. Eye movement measurements can then be made with the stimulator systems both off and on and the results compared. With suitable experimental design, this approach can be used to study the pathophysiology of the disease being treated, the mechanism by which DBS exerts it beneficial effects, and even aspects of normal neurophysiology.

This paper describes the use of quantitative measurement of eye movements in conjunction with stimulation of focal areas of the deep brain in order to study physiology, pathophysiology, and the mechanisms of deep brain stimulation.

The oculomotor system involves a large number of brain areas including parts of the basal ganglia, and various neurodegenerative diseases including ...

Neurodegeneration in an Animal Model of Chronic Amyloid-beta Oligomer Infusion Is Counteracted by Antibody Treatment Infused with Osmotic Pumps

Decline in hippocampal-dependent explicit memory (memory for facts and events) is one of the earliest clinical symptom of Alzheimer&#39;s disease (AD). It is well established that synapse loss and ensuing neurodegeneration are the best predictors for memory impairments in AD. Latest studies have emphasized the neurotoxic role of soluble amyloid-beta oligomers (A&#946;o) that begin to accumulate in the human brain approximately 10 to 15 yr before the clinical symptoms become apparent. Many reports indicate that soluble A&#946;o correlate with memory deficits in AD models and humans. The A&#946;o-induced neurodegeneration observed in neuronal and brain slice cultures has been more challenging to reproduce in many animal models. The model of repeated A&#946;o infusions shown here overcome this issue and allow addressing two key domains for developing new disease modifying therapies: identify biological markers to diagnose early AD, and determine the molecular mechanisms underpinning A&#946;o-induced memory deficits at the onset of AD. Since soluble A&#946;o aggregate relatively fast into insoluble A&#946; fibrils that correlate poorly with the clinical state of patients, soluble A&#946;o are prepared freshly and injected once per day during six days to produce marked cell death in the hippocampus. We used cannula specially design for simultaneous infusions of A&#946;o and continuous infusion of A&#946;o antibody (6E10) in the hippocampus using osmotic pumps. This innovative in vivo method can now be used in preclinical studies to validate the efficiency of new AD therapies that might prevent the deposition and neurotoxicity of A&#946;o in pre-dementia patients.

To study the effects of A&#946;o in vivo, we developed a model based on repeated hippocampal infusions of soluble A&#946;o coupled with continuous infusion of A&#946;o antibody (6E10) in the hippocampus using osmotic pumps to counteract the neurotoxic effect of A&#946;o.

Decline in hippocampal-dependent explicit memory (memory for facts and events) is one of the earliest clinical symptom of Alzheimer&#39;s disease (AD). It ...

Network Analysis of Foramen Ovale Electrode Recordings in Drug-resistant Temporal Lobe Epilepsy Patients

Approximately 30% of epilepsy patients are refractory to antiepileptic drugs. In these cases, surgery is the only alternative to eliminate/control seizures. However, a significant minority of patients continues to exhibit post-operative seizures, even in those cases in which the suspected source of seizures has been correctly localized and resected. The protocol presented here combines a clinical procedure routinely employed during the pre-operative evaluation of temporal lobe epilepsy (TLE) patients with a novel technique for network analysis. The method allows for the evaluation of the temporal evolution of mesial network parameters. The bilateral insertion of foramen ovale electrodes (FOE) into the ambient cistern simultaneously records electrocortical activity at several mesial areas in the temporal lobe. Furthermore, network methodology applied to the recorded time series tracks the temporal evolution of the mesial networks both interictally and during the seizures. In this way, the presented protocol offers a unique way to visualize and quantify measures that considers the relationships between several mesial areas instead of a single area.

This protocol describes a procedure to track the evolution of mesial network measures in temporal lobe epilepsy (TLE) patients. It is based on the combination of intracranial recordings with a novel numerical technique for data analysis. Specifically, we present a protocol for network analyses of foramen ovale recordings.