Name: measuring the carotid to femoral pulse wave velocity (cf-pwv) to evaluate arterial stiffness
Uploaded: 2018-05-03T13:30:00
Description: Watch this Scientific Journal Video about Measuring the Carotid to Femoral Pulse Wave Velocity Cf-PWV to Evaluate Arterial Stiffness at JoVE.com

This work is under the financial support from National key research and development program of China (Grant No. 2017YFC0111800) and the Shanghai municipal government (Grant ID. 2013ZYJB0902 and 15GWZK1002). Dr. Yi Zhang was supported by the National Nature Science Foundation of China (Grant ID. 81300239 and 81670377).

This protocol was approved by the Ethics Committee of Shanghai Tenth People&#39;s Hospital.
1. Recruitment of Participants
<ol>
	<li>Include Adults with a moderate heart rate (40 &#60; HR &#60; 160).</li>
	<li>Use the following exclusion criteria.
	<ol>
		<li>Exclude those without internal arteriovenous fistula for renal dialysis or any other peripheral arteriovenous fistula like that.</li>
		<li>Exclude those without peripheral arterial spasm, for example the Raynaud disease.</li>
		<li>Exc...

<ol>
	<li>Laurent, 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=Expert+consensus+document+on+arterial+stiffness:+methodological+issues+and+clinical+applications.">Expert consensus document on arterial stiffness: methodological issues and clinical applications.</a> Eur Heart J. 27 (21), 2588-2605 (2006).</li><li>Townsend, R. 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=Recommendations+for+Improving+and+Standardizing+Vascular+Research+on+Arterial+Stiffness:+A+Scientific+Statement+From+the+American+Heart+Association.">Recommendations for Improving and Standardizing Vascular Research on Arterial Stiffness: A Scientific Statement From the American Heart Association.</a> Hypertension. 66 (3), 698-722 (2015).</li><li>Niiranen, T. J., 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=Prevalence,+Correlates,+and+Prognosis+of+Healthy+Vascular+Aging+in+a+Western+Community-Dwelling+Cohort:+The+Framingham+Heart+Study.">Prevalence, Correlates, and Prognosis of Healthy Vascular Aging in a Western Community-Dwelling Cohort: The Framingham Heart Study.</a> Hypertension. 70 (2), 267-274 (2017).</li><li>Reference Values for Arterial Stiffness, 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=Determinants+of+pulse+wave+velocity+in+healthy+people+and+in+the+presence+of+cardiovascular+risk+factors:+'establishing+normal+and+reference+values.">Determinants of pulse wave velocity in healthy people and in the presence of cardiovascular risk factors: 'establishing normal and reference values.</a> Eur Heart J. 31 (19), 2338-2350 (2010).</li><li>Van Bortel, L. M., 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=Expert+consensus+document+on+the+measurement+of+aortic+stiffness+in+daily+practice+using+carotid-femoral+pulse+wave+velocity.">Expert consensus document on the measurement of aortic stiffness in daily practice using carotid-femoral pulse wave velocity.</a> J Hypertens. 30 (3), 445-448 (2012).</li><li>Salvi, 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> Pulse waves: how vascular hemodynamics affect blood pressure. , (2011).</li><li>Mancia, G., 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=2013+ESH/ESC+Guidelines+for+the+management+of+arterial+hypertension:+the+Task+Force+for+the+management+of+arterial+hypertension+of+the+European+Society+of+Hypertension+(ESH)+and+of+the+European+Society+of+Cardiology+(ESC).">2013 ESH/ESC Guidelines for the management of arterial hypertension: the Task Force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC).</a> J Hypertens. 31 (7), 1281-1357 (2013).</li><li>Yamashina, 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=Validity,+reproducibility,+and+clinical+significance+of+noninvasive+brachial-ankle+pulse+wave+velocity+measurement.">Validity, reproducibility, and clinical significance of noninvasive brachial-ankle pulse wave velocity measurement.</a> Hypertens Res. 25 (3), 359-364 (2002).</li><li>Tanaka, 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=Comparison+between+carotid-femoral+and+brachial-ankle+pulse+wave+velocity+as+measures+of+arterial+stiffness.">Comparison between carotid-femoral and brachial-ankle pulse wave velocity as measures of arterial stiffness.</a> J Hypertens. 27 (10), 2022-2027 (2009).</li><li>Lu, 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=Comparison+of+Carotid-Femoral+and+Brachial-Ankle+Pulse-Wave+Velocity+in+Association+With+Target+Organ+Damage+in+the+Community-Dwelling+Elderly+Chinese:+The+Northern+Shanghai+Study.">Comparison of Carotid-Femoral and Brachial-Ankle Pulse-Wave Velocity in Association With Target Organ Damage in the Community-Dwelling Elderly Chinese: The Northern Shanghai Study.</a> J Am Heart Assoc. 6 (2), (2017).</li><li>D'Agostino, R. B., 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=General+cardiovascular+risk+profile+for+use+in+primary+care:+the+Framingham+Heart+Study.">General cardiovascular risk profile for use in primary care: the Framingham Heart Study.</a> Circulation. 117 (6), 743-753 (2008).</li><li>Conroy, R. M., 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=Estimation+of+ten-year+risk+of+fatal+cardiovascular+disease+in+Europe:+the+SCORE+project.">Estimation of ten-year risk of fatal cardiovascular disease in Europe: the SCORE project.</a> Eur Heart J. 24 (11), 987-1003 (2003).</li><li>Zethelius, B., 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=Use+of+multiple+biomarkers+to+improve+the+prediction+of+death+from+cardiovascular+causes.">Use of multiple biomarkers to improve the prediction of death from cardiovascular causes.</a> N Engl J Med. 358 (20), 2107-2116 (2008).</li><li>Vernooij, J. W., 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=Hypertensive+target+organ+damage+and+the+risk+for+vascular+events+and+all-cause+mortality+in+patients+with+vascular+disease.">Hypertensive target organ damage and the risk for vascular events and all-cause mortality in patients with vascular disease.</a> J Hypertens. 31 (3), 492-499 (2013).</li><li>van der Veen, P. 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=Hypertensive+Target+Organ+Damage+and+Longitudinal+Changes+in+Brain+Structure+and+Function:+The+Second+Manifestations+of+Arterial+Disease-Magnetic+Resonance+Study.">Hypertensive Target Organ Damage and Longitudinal Changes in Brain Structure and Function: The Second Manifestations of Arterial Disease-Magnetic Resonance Study.</a> Hypertension. 66 (6), 1152-1158 (2015).</li><li>Ji, 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=Shanghai+Study:+cardiovascular+risk+and+its+associated+factors+in+the+Chinese+elderly-a+study+protocol+of+a+prospective+study+design.">Shanghai Study: cardiovascular risk and its associated factors in the Chinese elderly-a study protocol of a prospective study design.</a> BMJ Open. 7 (3), (2017).</li><li>O'Brien, 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=Practice+guidelines+of+the+European+Society+of+Hypertension+for+clinic,+ambulatory+and+self+blood+pressure+measurement.">Practice guidelines of the European Society of Hypertension for clinic, ambulatory and self blood pressure measurement.</a> J Hypertens. 23 (4), 697-701 (2005).</li><li>Agnoletti, D., 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=Pulse+wave+analysis+with+two+tonometric+devices:+a+comparison+study.">Pulse wave analysis with two tonometric devices: a comparison study.</a> Physiol Meas. 35 (9), 1837-1848 (2014).</li><li>Ji, 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=Shanghai+Study:+cardiovascular+risk+and+its+associated+factors+in+the+Chinese+elderly-a+study+protocol+of+a+prospective+study+design.">Shanghai Study: cardiovascular risk and its associated factors in the Chinese elderly-a study protocol of a prospective study design.</a> BMJ Open. 7 (3), e013880 (2017).</li><li>Zhang, 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=Comparison+study+of+central+blood+pressure+and+wave+reflection+obtained+from+tonometry-based+devices.">Comparison study of central blood pressure and wave reflection obtained from tonometry-based devices.</a> Am J Hypertens. 26 (1), 34-41 (2013).</li><li>Sharman, J. 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=Validation+of+non-invasive+central+blood+pressure+devices:+ARTERY+Society+task+force+consensus+statement+on+protocol+standardization.">Validation of non-invasive central blood pressure devices: ARTERY Society task force consensus statement on protocol standardization.</a> Eur Heart J. 38 (37), 2805-2812 (2017).</li><li>Millasseau, S., Agnoletti, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-invasive+estimation+of+aortic+blood+pressures:+a+close+look+at+current+devices+and+methods.">Non-invasive estimation of aortic blood pressures: a close look at current devices and methods.</a> Curr Pharm Des. 21 (6), 709-718 (2015).</li><li>Olsen, M. 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=A+call+to+action+and+a+lifecourse+strategy+to+address+the+global+burden+of+raised+blood+pressure+on+current+and+future+generations:+the+Lancet+Commission+on+hypertension.">A call to action and a lifecourse strategy to address the global burden of raised blood pressure on current and future generations: the Lancet Commission on hypertension.</a> Lancet. 388 (10060), 2665-2712 (2016).</li></ol>

Here, we demonstrate a widely accessible methodology to assess the participants&#39; novel preclinical vascular TOD, arterial stiffness, evaluated by cf-PWV. In order to compare PWs with minimal hemodynamic differences between measurements done prior to devices, only accept data when the brachial systolic and diastolic BP varied by less than 3 mmHg. This reduces the deviation caused by human manipulation. In this protocol, the critical steps are to have standardized patient conditions using 80% of the direct straight dis...

Arterial stiffening is a good marker for vascular aging evaluation1,2. The measurement of arterial stiffening is traditionally conducted using a pulse wave velocity (PWV) methodology that is an important and reliable measure of arterial stiffness1,3,4,5. Specifically, PWV represents the stiffness of a specific arterial segment. The pulse wave is transmitted through the arterial vessels in a specific segment, and its speed is inversely related to the viscoelastic properties of the wall itself6. PWV value increases with arterial stiffening.
Carotid-femoral PWV (cf-PWV) and brachial-ankle PWV (ba-PWV) are the 2 most frequently applied PWV measurements. They are widely used in clinical practice, where cf-PWV is popular in western countries and ba-PWV is popular in Asian countries.7,8. In fact, cf-PWV has been considered as the &#39;gold-standard&#39; measurement of arterial stiffness1. For cf-PWV, it is taken as representative of the PWV for the entire aorta. Besides, for ba- PWV, there is no true arterial pathway linking the measurement sites (brachial to ankle). The estimated ba-PWV represents the PWV for the entirety of the central and peripheral arterial system9. A previous study has reported that cf-PWV is superior to ba-PWV in associations with asymptomatic hypertensive target organ damage (TOD)10 (Figure 1).
Non-invasive devices for regional stiffness equipped with a specific tonometer are increasingly being used to measure the stiffness of the carotid to femoral segment1. In cf-PWV measurements, this device and a handheld tonometer create a steady waveform on the computer that can record high resolution digital waveform images and the specific PWV values (Figure 2). All these measurements need to be standardized. Here, we show how to record a good quality cf-PWV with this non-invasive tonometry-based device in a real-world setting.
Some established cardiovascular risk prediction models such as the Framingham risk score and the SCORE Risk Charts are mainly calculated and sorted by conventional risk factors11,12. However, some novel biomarkers should be added into the risk assessment model to improve the risk stratification13. In literature, arterial stiffening is considered as an intermediate state between conventional risk factors and clinical cardiovascular events14. Thus, adding cf-PWV into the risk assessment model may be a tool for risk stratification15,16.
Here, we generate a methodology plan to assess participants&#39; cf-PWV, together with PWA, to establish a standard protocol for arterial stiffening assessment.

<table>
	<tbody>
		<tr>
			<td>SphygmoCor tonometry-based device</td>
			<td>AtCor Medical, Australia</td>
			<td></td>
			<td>For central blood pressures and cf-PWV</td>
		</tr>
		<tr>
			<td>Electrodes</td>
			<td>AtCor Medical, Australia</td>
			<td></td>
			<td>To record the ECG</td>
		</tr>
		<tr>
			<td>Semiautomatic Oscillometric device</td>
			<td>OMRON Healthcare, kyoto, Japan</td>
			<td></td>
			<td>To measure brachial BP</td>
		</tr>
	</tbody>
</table>

measuring the carotid to femoral pulse wave velocity (cf-pwv) to evaluate arterial stiffness

For the elderly, arterial stiffening is a good marker for aging evaluation and it is recommended that the arterial stiffness be determined noninvasively by the measurement of carotid to femoral pulse wave velocity (cf-PWV) (Class I; Level of Evidence A). In literature, numerous community-based or disease-specific studies have reported that higher cf-PWV is associated with increased cardiovascular risk. Here, we discuss strategies to evaluate arterial stiffness with cf-PWV. Following the well-defined steps detailed here, e.g., proper position operator, distance measurement, and tonometer position, we will obtain a standard cf-PWV value to evaluate arterial stiffness. In this paper, a detailed stepwise method to record a good quality PWV and pulse wave analysis (PWA) using a non-invasive tonometry-based device will be discussed.

Cf-PWV (with this method) and ba-PWV (with other method10) were conducted in all of the 2098 participants from Northern Shanghai Study19. Both cf-PWV and ba-PWV were used in the same logistic regression model. In this model, age and gender were adjusted. The results showed that only cf-PWV, but not ba-PWV, was significantly associated with increased IMT and arterial plaque, which indicates the superiority of cf-PWV over ba-PWV in the associa...

Watch this Scientific Journal Video about Measuring the Carotid to Femoral Pulse Wave Velocity Cf-PWV to Evaluate Arterial Stiffness at JoVE.com

Measuring the Carotid to Femoral Pulse Wave Velocity Cf-PWV to Evaluate Arterial Stiffness

This protocol describes a method to standardize the measurements of carotid-femoral pulse wave velocity to evaluate arterial stiffness.

Measuring the Carotid to Femoral Pulse Wave Velocity (Cf-PWV) to Evaluate Arterial Stiffness

For the elderly, arterial stiffening is a good marker for aging evaluation and it is recommended that the arterial stiffness be determined noninvasively ...

The overall goal of this non-invasive, tonometry-based procedure is to collect good quality carotid to femoral pulse wave velocity data from human patients. Carotid to femoral pulse wave velocity and pulse wave data is collected using a non-invasive evaluation. A standard protocol is crucial to obtain an accurate value, especially when there are multiple operators.The implications of this technique extend towards the therapy and diagnosis because pulse wave velocity values increased with arterial stiffening. Though this method can provide insight into arterial stiffness, it can also be applied to other cardiovascular phenotypes, such as central blood pressure. Visual demonstration of this method is critical.The wave recording steps are difficult to learn because the tonometer must be correctly positioned over the artery fluctuation point. Make sure to practice this method before using it. The participant's cooperation is crucial, so explain the procedure well before gaining their consent.Conduct this procedure in a quiet room with a stable ambient temperature. Start with measuring the height and weight of the participant. Next, have the participant lie supine with their hands next to their body.Then, connect the three ECG leads to smooth, dry skin for an undisturbed ECG signal. Position the three electrodes according to the diagram. If, during the procedure, the patient's skin gets damp with sweat, wipe the skin dry.Have the patient rest for at least five minutes, and then measure the patient's blood pressure with a semiautomatic oscillometric device. Peripheral vascular dilation caused by artery occlusion when measuring brachial artery blood pressure will change the brachial artery pulse transmission. Resting is essential to avoid excessive deviation.Next, have the patient rest two minutes or longer, staying supine. Meanwhile, update the measurement device with the patient's information. Then, manually measure the distance from the SSN to the remote detection point.Next, determine the distance from the SSN to the proximal detection point, and then measure the distance between the two detection points. At the computer, select the PWA mode. Then, enter a value, ideally zero, for the SSN-carotid distance.Then, for the SSN-femoral distance, enter 0.8 times the carotid-to-femoral distance plus the SSN-carotid distance value. Now, start capturing data. Next, to measure the central blood pressure, put the tonometer on the radial artery fluctuation point, one to two centimeters above the radial styloid process.This is where fluctuations are often most strong and stable. Now, keep a stable grip on the tonometer, so it stays perpendicular to the skin. Once the quality and reproducibility of the tonometry measurements reach the standard, the signal recording will automatically stop.Next, at the computer, change the mode to PWV. Then, collect data with the tonometer, as before. After recording a stable waveform for 15 to 20 seconds, manually stop the recording.Measurements taken with the described method were compared to brachial-ankle PWV measurements collected using the conventional approach. Data was collected from 2, 098 participants. Both data sets were subjected to the same logistic regression model, with age and gender adjusted.The result shows that carotid-femoral PWV data was significantly associated with increased carotid intima-media thickness and arterial plaque, but the brachial-ankle PWV data was not. This supports the improvement of the described method over the conventional method. After watching this video, you should have a good understanding of how to obtain a standard PWV value to evaluate arterial stiffness.Once mastered, this technique can be done in 15 minutes if it is performed properly. While attempting this procedure, it's important to remember to make sure the participants meet the inclusion and exclusion criteria.

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Use of Animal Model of Sepsis to Evaluate Novel Herbal Therapies

Sepsis refers to a systemic inflammatory response syndrome resulting from a microbial infection. It has been routinely simulated in animals by several techniques, including infusion of exogenous bacterial toxin (endotoxemia) or bacteria (bacteremia), as well as surgical perforation of the cecum by cecal ligation and puncture (CLP)1-3. CLP allows bacteria spillage and fecal contamination of the peritoneal cavity, mimicking the human clinical disease of perforated appendicitis or diverticulitis. The severity of sepsis, as reflected by the eventual mortality rates, can be controlled surgically by varying the size of the needle used for cecal puncture2. In animals, CLP induces similar, biphasic hemodynamic cardiovascular, metabolic, and immunological responses as observed during the clinical course of human sepsis3. Thus, the CLP model is considered as one of the most clinically relevant models for experimental sepsis1-3.
Various animal models have been used to elucidate the intricate mechanisms underlying the pathogenesis of experimental sepsis. The lethal consequence of sepsis is attributable partly to an excessive accumulation of early cytokines (such as TNF, IL-1 and IFN-&gamma;)4-6 and late proinflammatory mediators (e.g., HMGB1)7. Compared with early proinflammatory cytokines, late-acting mediators have a wider therapeutic window for clinical applications. For instance, delayed administration of HMGB1-neutralizing antibodies beginning 24 hours after CLP, still rescued mice from lethality8,9, establishing HMGB1 as a late mediator of lethal sepsis. The discovery of HMGB1 as a late-acting mediator has initiated a new field of investigation for the development of sepsis therapies using Traditional Chinese Herbal Medicine. In this paper, we describe a procedure of CLP-induced sepsis, and its usage in screening herbal medicine for HMGB1-targeting therapies.

Sepsis refers to a systemic inflammatory response syndrome resulting from a microbial infection, and can be simulated by a surgical technique termed cecal ligation and puncture (CLP). Here we describe a method to use CLP-induced animal model to screen medicinal herbs for therapeutic agents.

Sepsis refers to a systemic inflammatory response syndrome resulting from a microbial infection. It has been routinely simulated in animals by several ...

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 ...

Pulse Wave Velocity Testing in the Baltimore Longitudinal Study of Aging

Carotid-femoral pulse wave velocity is considered the gold standard for measurements of central arterial stiffness obtained through noninvasive methods1.&#160;Subjects are placed in the supine position and allowed to rest quietly for at least 10 min prior to the start of the exam. The proper cuff size is selected and a blood pressure is obtained using an oscillometric device. Once a resting blood pressure has been obtained, pressure waveforms are acquired from the right femoral and right common carotid arteries. The system then automatically calculates the pulse transit time between these two sites (using the carotid artery as a surrogate for the descending aorta). Body surface measurements are used to determine the distance traveled by the pulse wave between the two sampling sites. This distance is then divided by the pulse transit time resulting in the pulse wave velocity. The measurements are performed in triplicate and the average is used for analysis.

Pulse wave velocity (PWV) measurement assesses arterial stiffness by a tonometry-based system that measures the speed with which arterial pressure wave travels along the arterial tree, typically approximating the time that it takes this wave to travel from the descending aorta (using the carotid artery as a surrogate) to the femoral artery. Carotid-femoral PWV increases two- to threefold across the adult lifespan.

Carotid-femoral pulse wave velocity is considered the gold standard for measurements of central arterial stiffness obtained through noninvasive ...

Measuring Ascending Aortic Stiffness In Vivo in Mice Using Ultrasound

We present a protocol for measuring in vivo aortic stiffness in mice using high-resolution ultrasound imaging. Aortic diameter is measured by ultrasound and aortic blood pressure is measured invasively with a solid-state pressure catheter. Blood pressure is raised then lowered incrementally by intravenous infusion of vasoactive drugs phenylephrine and sodium nitroprusside. Aortic diameter is measured for each pressure step to characterize the pressure-diameter relationship of the ascending aorta. Stiffness indices derived from the pressure-diameter relationship can be calculated from the data collected. Calculation of arterial compliance is described in this protocol.
This technique can be used to investigate mechanisms underlying increased aortic stiffness associated with cardiovascular disease and aging. The technique produces a physiologically relevant measure of stiffness compared to ex vivo approaches because physiological influences on aortic stiffness are incorporated in the measurement. The primary limitation of this technique is the measurement error introduced from the movement of the aorta during the cardiac cycle. This motion can be compensated by adjusting the location of the probe with the aortic movement as well as making multiple measurements of the aortic pressure-diameter relationship and expanding the experimental group size.

Measuring Ascending Aortic Stiffness In Vivo in Mice Using Ultrasound

We describe a technique for measuring aortic stiffness from its pressure-diameter relationship in vivo in mice. Aortic diameter is recorded by ultrasound and aortic pressure is measured invasively with a solid-state pressure catheter. Blood pressure is changed incrementally and the resulting diameter is measured.

We present a protocol for measuring in vivo aortic stiffness in mice using high-resolution ultrasound imaging. Aortic diameter is measured by ultrasound ...

A Murine Model of Arterial Restenosis: Technical Aspects of Femoral Wire Injury

Cardiovascular disease caused by atherosclerosis is the leading cause of death in the developed world. Narrowing of the vessel lumen, due to atherosclerotic plaque development or the rupturing of established plaques, interrupts normal blood flow leading to various morbidities such as myocardial infarction and stroke. In the clinic endovascular procedures such as angioplasty are commonly performed to reopen the lumen. However, these treatments inevitably damage the vessel wall as well as the vascular endothelium, triggering an excessive healing response and the development of a neointimal plaque that extends into the lumen causing vessel restenosis (re-narrowing). Restenosis remains a major cause of failure of endovascular treatments for atherosclerosis. Thus, preclinical animal models of restenosis are vitally important for investigating the pathophysiological mechanisms as well as translational approaches to vascular interventions. Among several murine experimental models, femoral artery wire injury is widely accepted as the most suitable for studies of post-angioplasty restenosis because it closely resembles the angioplasty procedure that injures both endothelium and vessel wall. However, many researchers have difficulty utilizing this model due to its high degree of technical difficulty. This is primarily because a metal wire needs to be inserted into the femoral artery, which is approximately three times thinner than the wire, to generate sufficient injury to induce prominent neointima. Here, we describe the essential surgical details to effectively overcome the major technical difficulties of this model. By following the presented procedures, performing the mouse femoral artery wire injury becomes easier. Once familiarized, the whole procedure can be completed within 20 min.

The mouse femoral artery wire injury model of restenosis is technically challenging. In this protocol we show the key technical details essential for successfully performing wire injury to induce consistent&#160;neointima for studies of restenosis.

Cardiovascular disease caused by atherosclerosis is the leading cause of death in the developed world. Narrowing of the vessel lumen, due to ...

Ultrasound-based Pulse Wave Velocity Evaluation in Mice

Arterial stiffness can be evaluated by calculating pulse wave velocity (PWV), i.e., the speed with which the pulse wave travels in a conduit vessel. This parameter is being increasingly investigated in small rodent models in which it is used for assessing alterations in vascular function related to particular genotypes/treatments or for characterizing cardiovascular disease progression. This protocol describes an image processing algorithm which leads to non-invasive arterial PWV measurement in mice using ultrasound (US) images only. The proposed technique has been used to assess abdominal aorta PWV in mice and evaluate its age-associated changes.
Abdominal aorta US scans are obtained from mice under gaseous anesthesia using a specific US device equipped with high-frequency US probes. B-mode and Pulse-Wave Doppler (PW-Doppler) images are analyzed in order to obtain diameter and mean velocity instantaneous values, respectively. For this purpose, edge detection and contour tracking techniques are employed. The single-beat mean diameter and velocity waveforms are time aligned and combined in order to achieve the diameter-velocity (lnD-V) loop. PWV values are obtained from the slope of the linear part of the loop, which corresponds to the early systolic phase.
With the present approach, anatomical and functional information about the mouse abdominal aorta can be non-invasively achieved. Requiring the processing of US images only, it may represent a useful tool for the non-invasive characterization of different arterial sites in the mouse in terms of elastic properties. The application of the present technique can be easily extended to other vascular districts, such as the carotid artery, thus providing the possibility to obtain a multi-site arterial stiffness assessment.

Arterial stiffness represents a key factor in cardiovascular disease and pulse wave velocity (PWV) can be considered as a surrogate index for arterial stiffness. This protocol describes an image processing algorithm for calculating PWV in mice based on ultrasound image processing that is applicable at different arterial sites.

Arterial stiffness can be evaluated by calculating pulse wave velocity (PWV), i.e., the speed with which the pulse wave travels in a conduit vessel. This ...

In Vivo Gene Transfer to the Rabbit Common Carotid Artery Endothelium

The goal of this method is to introduce a transgene into the endothelium of isolated segments of both rabbit common carotid arteries. The method achieves focal endothelial-selective transgenesis, thereby allowing an investigator to determine the biological roles of endothelial-expressed transgenes and to quantify the in vivo transcriptional activity of DNA sequences in large artery endothelial cells. The method uses surgical isolation of rabbit common carotid arteries and an arteriotomy to deliver a transgene-expressing viral vector into the arterial lumen. A short incubation period of the vector in the lumen, with subsequent aspiration of the lumen contents, is sufficient to achieve efficient and durable expression of the transgene in the endothelium, with no detectable transduction or expression outside of the isolated arterial segment. The method allows assessment of the biological activities of transgene products both in normal arteries and in models of human vascular disease, while avoiding systemic effects that could be caused either by targeting gene delivery to other sites (e.g. the liver) or by the alternative approach of delivering genetic constructs to the endothelium by germ line transgenesis. Application of the method is limited by the need for a skilled surgeon and anesthetist, a well-equipped operating room, the costs of purchasing and housing rabbits, and the need for expertise in gene-transfer vector construction and use. Results obtained with this method include: transgene-related alterations in arterial structure, cellularity, extracellular matrix, or vasomotor function; increases or reductions in arterial inflammation; alterations in vascular cell apoptosis; and progression, retardation, or regression of diseases such as intimal hyperplasia or atherosclerosis. The method also allows measurement of the ability of native and synthetic DNA regulatory sequences to alter transgene expression in endothelial cells, providing results that include: levels of transgene mRNA, levels of transgene protein, and levels of transgene enzymatic activity.

In Vivo Gene Transfer to the Rabbit Common Carotid Artery Endothelium

This method is to introduce a transgene into the endothelium of rabbit carotid arteries. Introduction of the transgene allows the assessment of the biological role of the transgene product either in normal arteries or disease models. The method is also useful for measuring activity of DNA regulatory sequences.

The goal of this method is to introduce a transgene into the endothelium of isolated segments of both rabbit common carotid arteries. The method achieves ...

A Clinical Trial Assessing the Safety, Efficacy, and Delivery of Olive-Oil-Based Three-Chamber Bags for Parenteral Nutrition

Limited evidence exists to precisely estimate efficacy and safety differences between parenteral nutrition (PN) prepared using olive-oil-based three-chamber bags (3CBs) and soybean-oil-based compounded bags (CoBs) in hospitalized adult patients. We designed a multicenter, randomized, prospective, open-label, noninferiority protocol to compare the efficacy, safety, and distribution of olive-oil-based 3CBs and soybean-oil-based CoB formulations in adult Chinese patients requiring PN during surgical intervention. Subjects were randomized to receive either one of the study treatments using an interactive voice or web-based recognition system in accordance with the randomization code. Randomization was further stratified based on the study site and surgical category. Both treatment groups received similar amounts of calories and protein. In addition, the two study treatments contained a similar composition of the amino-acid component. The only difference between the two PN formulations was the lipid constitution. The duration of administration of study treatments was a minimum of 5 days up to a maximum of 14 days after the surgical procedure. The primary efficacy endpoint was serum prealbumin levels on day 5 of the study. Noninferiority was proved if the anti-log of the lower bound of the 95% confidence interval (CI) of the treatment difference was at least 0.80. Other efficacy measures included treatment preparation time; duration to achieve tolerability of oral nutrition; associated infectious complications; length of hospitalization; and laboratory assessment of markers of nutrition, inflammation, metabolism, and oxidative stress. A total of 458 patients were enrolled in the study. The results showed that olive-oil-based 3CBs were non-inferior to soybean-based CoBs, besides being well tolerated. The infection rate was found to be significantly lower in the olive-oil-based 3CB group. Thus, this study may be used as a reference for future research on lipid emulsion and 3CBs.

Here, we present a protocol for a study comparing the efficacy, safety, and delivery of olive-oil-based 3CB and soybean-oil-based CoB formulations in adults requiring parenteral nutrition. The results revealed that olive-oil-based 3CBs is non-inferior and well tolerated compared to soybean formulations.

Limited evidence exists to precisely estimate efficacy and safety differences between parenteral nutrition (PN) prepared using olive-oil-based ...

Using a Knee Arthrometer to Evaluate Tissue-specific Contributions to Knee Flexion Contracture in the Rat

Normal knee range of motion (ROM) is critical to well-being and allows one to perform basic activities such as walking, climbing stairs and sitting. Lost ROM is called a joint contracture and results in increased morbidity. Due to the difficulty of reversing established knee contractures, early detection is important, and hence, knowing risk factors for their development is essential. The rat represents a good model with which the effect of an intervention can be studied due to the similarity of rat knee anatomy to that of humans, the rat's ability to tolerate long durations of knee immobilization in flexion, and because mechanical data can be correlated with histologic and biochemical analysis of knee tissue.
Using an automated arthrometer, we demonstrate a validated, precise, reproducible, user-independent method of measuring the extension ROM of the rat knee joint at specific torques. This arthrometer can be used to determine the effects of interventions on knee joint ROM in the rat.

The goal of the protocol is to measure the extension range of motion of the rat knee. The effects of various diseases that increase the stiffness of the knee joint and the effectiveness of treatments can be quantified.

Normal knee range of motion (ROM) is critical to well-being and allows one to perform basic activities such as walking, climbing stairs and sitting. Lost ...

Improved Renal Denervation Mitigated Hypertension Induced by Angiotensin II Infusion

The benefits of renal sympathetic denervation (RDN) on blood pressure have been proved in a large number of clinical trials in recent years. However, the regulatory mechanism of RDN on hypertension remains elusive. Thus, it&#39;s essential to establish a simpler RDN model in mice. In this study, osmotic mini pumps filled with Angiotensin II were implanted in 14-week-old C57BL/6 mice. One week after the implantation of the mini-osmotic pump, a modified RDN procedure was performed on bilateral renal arteries of the mice using phenol. Age-sex-matched mice were given saline and served as sham group. Blood pressure was measured at baseline and every week subsequently for 21 days. Then, renal artery, abdominal aorta and heart were collected for histological examination using H&#38;E and Masson staining. In this study, we present a simple, practical, repeatable, and standardized RDN model, which can control hypertension and alleviate cardiac hypertrophy. The technique can denervate peripheral renal sympathetic nerves without renal artery damage. Compared to previous models, the modified RDN facilitates the study of the pathobiology and pathophysiology of hypertension.

Here, we present a protocol for renal sympathetic denervation (RDN) in mice with hypertension induced by Angiotensin II infusion. The procedure is repeatable, convenient and allows to study the regulatory mechanisms of RDN on hypertension and cardiac hypertrophy.

The benefits of renal sympathetic denervation (RDN) on blood pressure have been proved in a large number of clinical trials in recent years. However, the ...