This work was supported by a grant from the Virginia Tech College of Science Discovery Fund.

All methods described below including the use of human volunteers have been reviewed and approved by the local Institutional Review Board (IRB), and are in accordance with the Declaration of Helsinki and Belmont Report. All participants (N=72) signed informed consent as proscribed by the IRB protocol. Inclusion/exclusion criteria and discontinuation procedures were designed to maximize participant safety, and any deviation from these procedures should be considered in light of their impact on risk and tolerability to human subjects. In the context of the work presented here, the exclusionary criteria restricted participation to individuals with no personal or family history of inflammatory conditions, or any licit or illicit substances. The justification for doing so is that these factors may influence responses to the MED testing procedure.
1. Participant Selection
<ol>
	<li>Use the following inclusion criteria: 18-55 years old; in good general health as determined by Medical Symptom Checklist (MSCL)5; can understand and communicate about the lab safety protocol presented in English; can provide written consent.</li>
	<li>Use the following exclusion criteria: Fitzpatrick skin type I, as determined by self-report; uses commercial tanning equipment regularly; skin wounds or lesions at the planned site of exposure; current skin cancer, or personal history of skin cancer; family history of skin cancer; diabetes; psoriasis or other inflammatory skin condition; peripheral vascular disease, peripheral arterial disease, Raynaud&#39;s disease, or any other diagnosed circulatory disorders; any involuntary motor disorders; allergic to adhesive tape; takes inhaled steroids for asthma (e.g., Fluticasone); takes any corticosteroids; 2 or more of the following (diagnosed hypertension, hyperlipidemia, high cholesterol, smoke cigarettes, family history of coronary or atherosclerotic disease (parents/siblings prior to age 55)); active substance dependence - legal or illicit; people with substance dependence new to recovery (less than one year); use of medications that affects CNS function, including psychotropics, opiate medication or corticosteroids, during the last 3 months; any prescribed psychotropic medications, currently or during the last 3 months (These include medications for anxiety, depression, or other psychological problems).</li>
</ol>
2. Scheduling and Preparation for the MED
<ol>
	<li>Schedule participants for two appointments: the first, the MED exposure event (approximately 45 min), and the second, a follow-up to gather spectrophotometry readings (approximately 10 min). Schedule the follow-up appointment for 24 h subsequent to the first appointment.</li>
	<li>Before participants arrive, lay out and set up essential equipment including two dose testing cuffs and safety equipment. Have a variety of UV-protective clothing (such as UV-protective sports sleeves, UV-protective gloves, long sleeve medical scrubs, UV-protective sheets and tape to affix the sheets) for both the participant and the researcher to cover all skin exposed to UV radiation.</li>
	<li>Calibrate the spectrophotometer according to manufacturer specifications. Do this for each subject and each session.</li>
</ol>
3. Determining Fitzpatrick Skin Type (FST)
<ol>
	<li>When the participant arrives for the MED exposure event (Visit 1), identify FST either through self-report or spectrophotometry. To maximize participant safety, do not conduct MED testing on participants categorized as FST 1. For all other Fitzpatrick Skin Types (2&#8212;6), use the FST score to determine which exposure schedule should be used.</li>
</ol>
4. Cuff 1 Application
<ol>
	<li>Explain to the participant how MED testing works and solicit questions before proceeding.</li>
	<li>Generally, perform the MED procedure on the inside of the non-dominant forearm.</li>
	<li>Place Cuff 1 (with all aperture coverings removed) avoiding freckles, moles, scars, hair (to the extent possible), and any cuts, bruises or lesions on the skin. Remove only the protective wax paper backing from the lateral (not central) portions of Cuff 1. It is important that the wax paper backing from the central portion of Cuff 1 not be removed, as the adhesive has a strong potential to irritate the skin when peeled off after baseline readings, causing reddening of skin proximal to the apertures.</li>
	<li>After situating Cuff 1 at the intended exposure site, place landmarks using a permanent marker to ensure that Cuff 2 will be situated at precisely the same location. Mark the skin at four points outside of the creases of each of the side flaps of Cuff 1, the upper right, upper left, lower right and lower left points.
	<ol>
		<li>Make these marks dark enough to survive approximately 24 h, as they will also be used to place Cuff 3 in precisely the same location at the follow-up appointment 24 h later.</li>
	</ol>
	</li>
</ol>
5. Baseline Reading: Cuff 1 Application
<ol>
	<li>Using a spectrophotometer that has been calibrated according to manufacturer specifications, obtain and permanently record readings at each of the six open apertures in sequence.</li>
	<li>Ensure that the spectrophotometer is placed the center of the cuff apertures while avoiding moles, scars, or other blemishes to the extent possible.</li>
	<li>Permanently record all &#8220;SCI&#8221; values (L, A, B). To ensure consistent readings with the same calibration point, keep the spectrophotometer in the ON for the duration of the MED procedure and do not turn off until the post-exposure readings have been completed.</li>
	<li>After baseline spectrophotometry measurements have been recorded, remove Cuff 1. To minimize participant discomfort, apply medical adhesive solvent to the perimeter of Cuff 1 as it is peeled off, which will prevent painful removal of hair on the arm.</li>
</ol>
6. Pre-exposure Reading: Cuff 2 Application
<ol>
	<li>After removal of Cuff 1, situate Cuff 2 at the same location using the landmarks drawn on the skin for Cuff 1. The full adhesive backing may be exposed and applied to ensure that Cuff 2 is sufficiently sealed to prevent cross exposure among apertures due to insufficient adhesion to the skin.</li>
	<li>Have both the participant and the researcher don UV-protective clothing and safety accessories. At minimum, the participant, the technician administering the procedure and any other parties in the room must don UV-protective glasses. Technicians should wear long sleeves or use a UV-protective sleeve.</li>
	<li>Prior to activating the lamp, have the technician assist the participant in covering all exposed skin, including the arm above the patch, the arm and wrist below the patch, the hand, and parts of the front or back of the arm that may be exposed on the sides of the patch (UV-protective sheets and tape to affix the sheets may be helpful for this). Additionally, some participants wearing shirts with open necklines may want to drape UV-protective cloth over their neck and chest if these areas will be close to the UV source.</li>
	<li>Spread a UV-protective cloth under the participant&#8217;s arm (to reduce reflectance off the table surface).</li>
</ol>
7. MED Procedure: Pre-exposure
NOTE: The rays from the lamp must be perpendicular to the exposure site. In general, physical movement of the lamp is less possible than movement or arrangement of the angle of participants&#8217; arm.
<ol>
	<li>Prior to activating the lamp, arrange the participant&#8217;s arm such that the UV rays from the lamp will be perpendicular to the angle of Cuff 2 on the participant&#8217;s arm.</li>
	<li>Identify the proper distance between the lamp and Cuff 2 on the participant&#8217;s arm. Place the radiometer&#8217;s sensor facing the UV lamp parallel to the surface of the skin and as close as possible to the location of Cuff 2.</li>
	<li>Cover the participants arm with a UV proof cloth to prevent exposure, and briefly activate the lamp to adjust the distance to Cuff 2 until the radiometer&#8217;s sensor reads 270 &#956;W/cm2.
	<ol>
		<li>To achieve this reading, adjust the distance between the lamp and the surface of the skin until the radiometer reads 270 &#956;W/cm2 (&#177; 10 &#956;W). Once the proper distance has been determined, deactivate the lamp. 
		NOTE: It is important to note here that small differences in the angle of the radiometer will greatly affect the reading. Thus, the angle of the radiometer should be as close to parallel to the surface of the skin as possible.</li>
	</ol>
	</li>
	<li>Make further adjustments in distance throughout the exposure session to prevent drift in the location of the arm. At each reading, confirm the distance and readjust as necessary to maintain radiometer readings at approximately 270 &#956;W/cm2 (&#177; 10 &#956;W).</li>
</ol>
8. MED Procedure: Exposure
<ol>
	<li>Use a stopwatch to implement the MED schedule. Remove the first aperture covering before activating the UV source. Activate the source and the stopwatch simultaneously and remove each aperture covering on Cuff 2 according to the schedule specified below, based on FST.</li>
	<li>At the point of removal for each aperture covering, record the radiometer reading when the radiometer is held parallel to the surface of the skin and pointed at the lamp. If the distance has changed, adjust the distance to lamp to ensure that the radiometer once again reads 270 (&#177; 10) &#956;W/cm2.</li>
	<li>Have the technician monitor the participant&#8217;s arm to ensure consistent positioning. In particular, readjust the arm if the arm rotates, as many participants will rotate the arm as they relax. Subsequent to any adjustments, re-confirm that the radiometer reads 270 &#956;W/cm2 (&#177; 10 &#956;W).</li>
	<li>Turn off the lamp at precise time specified by the dosage schedule in Table 1. Do not deactivate the stopwatch, as an additional series of spectrophotometer readings should be gathered exactly 7 minutes subsequent to deactivation of the lamp, as described below.</li>
</ol>
9. 7 Min Post-exposure Reading
<ol>
	<li>Exactly 7 minutes subsequent to the deactivation of the lamp, record the final spectrophotometer readings from each aperture in Cuff 2. The purpose in collecting data immediately subsequent to the exposure procedure is to first confirm no adverse reaction to the UV radiation, and second to evaluate initial responses, which in some cases can be slight, but measurably different from baseline (pre-exposure) values. Any increase in redness after 7 minutes is likely to be a thermal effect and not erythema. 
	NOTE: An adverse reaction to UV radiation exposure after 7 minutes is likely related to the minimal urticarial dose of solar urticaria, an acquired photosensitivity disorder. Photosensitivity disorders are assessed prior to the MED procedure and subjects with these disorders should be ruled out. However, if this is observed at any point during testing the exposure protocol should be discontinued immediately.</li>
	<li>After exposure to UV radiation, Cuff 2 can be particularly difficult to remove. Use medical-grade adhesive solvent, if necessary, to minimize discomfort to participants during removal of Cuff 2. Participants with particularly hirsute or otherwise sensitive skin may find it helpful to apply either olive oil or alcohol-based adhesive remover under the edge of Cuff 2, as they remove the patch slowly. After Cuff 2 is removed participants may have residual adhesive on their skin, which can also be removed with either olive oil or medical adhesive solvent.</li>
	<li>Prior to departure from the exposure session, remind participants not to wash the landmarks and not apply any lotions to the exposure site.</li>
</ol>
10. Follow-up Appointment: Cuff 3 Application
<ol>
	<li>Before the participant arrives, calibrate the spectrophotometer according to manufacturer specifications.</li>
	<li>Prepare Cuff 3 by removing all of the aperture coverings (leaving the white wax paper backing on the central portion of the patch). When placing Cuff 3 on the participant&#8217;s arm, remove the white wax paper backing from the two side flaps of the patch. Using the landmarks on the participant&#8217;s forearm, place Cuff 3 in the same location as the previous two patches.</li>
	<li>Take a reading at each of the six open apertures in sequence. Additionally, visually inspect each aperture and record whether there appears to be visual evidence of an erythema response in each of the six apertures (red or pink skin indicates erythema). After permanently recording spectrophotometer readings, remove Cuff 3, using solvent if necessary.</li>
	<li>To further enhance participant comfort and safety, provide 4-6 single-use burn gel or aloe vera, and indicate to the participant that if the exposure site becomes itchy or uncomfortable, it may be treated like a sunburn with these or similar over the counter products.</li>
</ol>

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	<li>Magnus, I. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dermatological+Photobiology:+Clinical+and+Experimental+Aspects.">Dermatological Photobiology: Clinical and Experimental Aspects.</a> Blackwell Scientific Publications. , (1976).</li><li>Grundmann-Kollmann, 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=Phototherapy+for+atopic+eczema+with+narrow-band+UVB.">Phototherapy for atopic eczema with narrow-band UVB.</a> Journal of the American Academy of Dermatology. 40 (6), 995-997 (1999).</li><li>Honigsmann, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phototherapy+for+psoriasis.">Phototherapy for psoriasis.</a> Clinical and Experimental Dermatology. 26 (4), 343-350 (2001).</li><li>Heckman, C. 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=Minimal+Erythema+Dose+(MED)+testing.">Minimal Erythema Dose (MED) testing.</a> Journal of Visualized Experiments. (75), e50175 (2013).</li><li>Kroenke, K., 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=Physical+symptoms+in+primary+care.+Predictors+of+psychiatric+disorders+and+functional+impairment.">Physical symptoms in primary care. Predictors of psychiatric disorders and functional impairment.</a> Archives of Family Medicine. 3 (9), 774-779 (1994).</li><li>Coelho, S. 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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=Evidence+for+a+new+paradigm+for+ultraviolet+exposure:+a+universal+schedule+that+is+skin+phototype+independent.">Evidence for a new paradigm for ultraviolet exposure: a universal schedule that is skin phototype independent.</a> Photodermatology Photoimmunology &amp; Photomedicine. 28 (4), 187-195 (2012).</li><li>Pershing, L. K., 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=Reflectance+spectrophotometer:+The+dermatologists'+sphygmomanometer+for+skin+phototyping.">Reflectance spectrophotometer: The dermatologists' sphygmomanometer for skin phototyping.</a> Journal of Investigative Dermatology. 128 (7), 1633-1640 (2008).</li><li>Kollias, N., Baqer, A., Sadiq, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimum+Erythema+Dose+Determination+in+Individuals+of+Skin+Type-V+and+Type-Vi+with+Diffuse-Reflectance+Spectroscopy.">Minimum Erythema Dose Determination in Individuals of Skin Type-V and Type-Vi with Diffuse-Reflectance Spectroscopy.</a> Photodermatology Photoimmunology &amp; Photomedicine. 10 (6), 249-254 (1994).</li><li>Treesirichod, A., Chansakulporn, S., Wattanapan, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlation+Between+Skin+Color+Evaluation+by+Skin+Color+Scale+Chart+and+Narrowband+Reflectance+Spectrophotometer.">Correlation Between Skin Color Evaluation by Skin Color Scale Chart and Narrowband Reflectance Spectrophotometer.</a> Indian Journal of Dermatology. 59 (4), 339-342 (2014).</li><li>Gambichler, T., 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=Reference+limits+for+erythema-effective+UV+doses.">Reference limits for erythema-effective UV doses.</a> Photochemistry and Photobiology. 82 (4), 1097-1102 (2006).</li><li>Kool, 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=Suction+blister+fluid+as+potential+body+fluid+for+biomarker+proteins.">Suction blister fluid as potential body fluid for biomarker proteins.</a> Proteomics. 7 (20), 3638-3650 (2007).</li><li>Clark, K. E., Lopez, H., Abdi, B. 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=Multiplex+cytokine+analysis+of+dermal+interstitial+blister+fluid+defines+local+disease+mechanisms+in+systemic+sclerosis.">Multiplex cytokine analysis of dermal interstitial blister fluid defines local disease mechanisms in systemic sclerosis.</a> Arthritis Research &amp; Therapy. 17, 73 (2015).</li><li>Rosenkranz, M. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+comparison+of+mindfulness-based+stress+reduction+and+an+active+control+in+modulation+of+neurogenic+inflammation.">A comparison of mindfulness-based stress reduction and an active control in modulation of neurogenic inflammation.</a> Brain Behavior and Immunity. 27 (1), 174-184 (2013).</li><li>Smith, T. J., Wilson, M. A., Young, A. J., Montain, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+suction+blister+model+reliably+assesses+skin+barrier+restoration+and+immune+response.">A suction blister model reliably assesses skin barrier restoration and immune response.</a> Journal of Immunological Methods. 417, 124-130 (2015).</li><li>Holm, L. 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=A+Suction+Blister+Protocol+to+Study+Human+T-cell+Recall+Responses+In+Vivo.">A Suction Blister Protocol to Study Human T-cell Recall Responses In Vivo.</a> Journal of Visualized Experiments. (138), 57554 (2018).</li><li>Seitz, J. C., Whitmore, C. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+erythema+and+tanning+responses+in+human+skin+using+a+tri-stimulus+colorimeter.">Measurement of erythema and tanning responses in human skin using a tri-stimulus colorimeter.</a> Dermatologica. 177 (2), 70-75 (1988).</li><li>Henriksen, M., Na, R., Agren, M. S., Wulf, H. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimal+erythema+dose+after+multiple+UV+exposures+depends+on+pre-exposure+skin+pigmentation.">Minimal erythema dose after multiple UV exposures depends on pre-exposure skin pigmentation.</a> Photodermatology Photoimmunology &amp; Photomedicine. 20 (4), 163-169 (2004).</li><li>Stamatas, G. N., Zmudzka, B. Z., Kollias, N., Beer, J. 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The authors on this study declare no conflicts of interest, financial or otherwise.

Precision implementation of MED testing as described here could offer several advantages over other extant lab-based inflammatory challenges that have achieved popular use. For example, suction blister protocols17,18,19 raise a fluid-filled blister on the skin that is subsequently aspirated with a syringe to gain direct access to the cytokine microenvironment. Although skin blistering is a well-known tool for studying skin immun...

Minimal erythema dose (MED) testing is an FDA-approved procedure to evaluate cutaneous sensitivity to radiation typically in the UVB range, although the MED can be determined at other wavelengths in the UV and visible spectrum1. Erythema is defined as superficial reddening on the surface of the skin caused by engorgement of capillaries (later stages of erythema are more commonly known as sunburn). MED testing has been used extensively in the dermatology literature and clinical phototherapy settings to identify the minimal amount of ultraviolet (UV) radiation that will produce the smallest unit of measurable change in the redness of the skin. MED testing can be accomplished with a commercially available UV lamp, equivalent to what is used in most commercial tanning facilities.
MED testing involves continuous dispersal of UV radiation or light from the visible spectrum onto the surface of the skin for a predetermined length of time, with dosage schedules depending primarily on pigmentation of the skin and the intensity and type of radiation. This procedure is commonly used in clinical settings to determine dosage schedules for patients receiving UV radiation therapy for skin conditions such as psoriasis and eczema2,3. Basic procedures for determining the MED in clinical settings have been described elsewhere4, and can be used to adjust the total dosage of UV radiation upward or downward, depending on individual variation in skin sensitivity.
Skin pigmentation is perhaps the most important subject-specific variable in conducting and measuring results from the MED procedure6. This is because the duration of UV exposure required to evoke the minimal erythema response is principally determined by the lightness or darkness of the participant&#8217;s skin, as defined by the participant&#8217;s Fitzpatrick skin type (FST). FST7 is a numerical scheme for classifying human skin color. The Fitzpatrick scale is a recognized tool for dermatological research into human skin pigmentation8,9, and classifies human skin into one of six categories from lightest (FST I) to darkest (FST VI).
Darker FST typologies require longer UV duration, therefore accurate classification of FST is important. There is an extensive literature on methods for accurate assessment of FST, using a wide variety of approaches including self-report, dermatologist interview and instrumentation-based assessment. Observer ratings of FST have been shown to be correlated with current, but not natural skin color10, however FST can be determined subjectively11 using self-report via questionnaire12 and/or objective assessment via spectrophotometry. Fitzpatrick typing by spectrophotometry has been shown to correlate closely to participant self-report in a number of studies10,13,14,15.
Despite the utility and widespread use of MED testing in clinical services, this procedure has not been widely adopted in laboratory settings for measurement of individual variation in response to pro-inflammatory stimulation. The purpose of the methodology outlined here is to provide techniques and step-by-step procedures that increase the precision and reproducibility of the MED testing procedure, in order to facilitate future work in laboratory settings focused on fine-grained quantification of intra-individual variability in inflammatory response. We further provide representative results that illustrate the capability of this standardized protocol to accurately capture person-to-person variation in inflammation.

<table>
	<tbody>
		<tr>
			<td>6-aperture dose testing patch (&#8220;Cuff&#8221;)</td>
			<td>Daavlin</td>
			<td>&#160;</td>
			<td>&#160;</td>
		</tr>
		<tr>
			<td>Medical grade adhesive solvent</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Non-reflective UV proof cloth</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Radiometer</td>
			<td>SolarLight</td>
			<td>Model 6.2 UVB Meter</td>
			<td></td>
		</tr>
		<tr>
			<td>Single use aloe or burn gel</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Spectrophotometer</td>
			<td>Konika-Minolta</td>
			<td>CM-2600D</td>
			<td></td>
		</tr>
		<tr>
			<td>Stopwatch</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>UV lamp &#8211; Fiji Sun</td>
			<td>Sperti</td>
			<td></td>
			<td>Emission spectrum 280nm-400nm, approximately 25% UVB</td>
		</tr>
		<tr>
			<td>UV-proof safety glasses (2 pair)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>UV-proof sleeve</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>White cotton gloves (2 pair)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

precision implementation of minimal erythema dose (med) testing to assess individual variation in human inflammatory response

Minimal erythema dose (MED) testing is frequently used in clinical settings for determining the smallest amount of ultraviolet (UV) irradiation necessary to produce erythema (inflammatory reddening) on the surface of the skin. In this context, the MED is regarded as a key factor in determining starting doses for UV phototherapy for common skin conditions such as psoriasis and eczema. In research settings, MED testing also has potential to be a powerful tool for assessing within- and between-persons variation in inflammatory responses. However, MED testing has not been widely adopted for use in research settings, likely owing to a lack of published guidelines, which is a barrier to obtaining reproducible results from this assay. Also, protocols and equipment for establishing MED vary widely, making it difficult to compare results across laboratories. Here, we describe a precise and reproducible method to induce and measure superficial erythema using newly designed protocols and methods that can easily be adapted to other equipment and laboratory environments. The method described here includes detail on procedures that will allow extrapolation of a standardized dosage schedule to other equipment so that this protocol can be adapted to any UV radiation source.

The timing schedule presented in Table 1 is a novel dosage schedule that was calculated to capture the MED, on average, at the mid-point of the exposure event (i.e., aperture 3 or 4) for each FST. The basis for the calculated schedule is as follows.
Prior work has established that for individuals with FST 2, the median MED for radiation in the UVB range is 66.9 milliwatts (mW) per cm2, 77.429 mW/cm2 for FST 3 and 85.0 for FST 416. ...

Watch this Scientific Journal Video about Precision Implementation of Minimal Erythema Dose MED Testing to Assess Individual Variation in Human Inflammatory Response at JoVE.com

Precision Implementation of Minimal Erythema Dose MED Testing to Assess Individual Variation in Human Inflammatory Response

Minimal erythema dose (MED) testing is used to establish dosage schedules for ultraviolet radiation phototherapy. It can assess individual variation in inflammatory response but lacks methodology for achieving reproducible results. Here, we present a precision implementation of MED and demonstrate its ability to capture individual variation in inflammatory response.

Precision Implementation of Minimal Erythema Dose (MED) Testing to Assess Individual Variation in Human Inflammatory Response

Minimal erythema dose (MED) testing is frequently used in clinical settings for determining the smallest amount of ultraviolet (UV) irradiation necessary ...

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8.4K Views.  Virginia Tech. Minimal erythema dose (MED) testing is used to establish dosage schedules for ultraviolet radiation phototherapy. It can assess individual variation in inflammatory response but lacks methodology for achieving reproducible results. Here, we present a precision implementation of MED and demonstrate its ability to capture individual variation in inflammatory response.

Video: Precision Implementation of Minimal Erythema Dose MED Testing to Assess Individual Variation in Human Inflammatory Response

Minimal Erythema Dose (MED) Testing

Ultraviolet radiation (UV) therapy is sometimes used as a treatment for various common skin conditions, including psoriasis, acne, and eczema. The dosage of UV light is prescribed according to an individual's skin sensitivity. Thus, to establish the proper dosage of UV light to administer to a patient, the patient is sometimes screened to determine a minimal erythema dose (MED), which is the amount of UV radiation that will produce minimal erythema (sunburn or redness caused by engorgement of capillaries) of an individual's skin within a few hours following exposure. This article describes how to conduct minimal erythema dose (MED) testing. There is currently no easy way to determine an appropriate UV dose for clinical or research purposes without conducting formal MED testing, requiring observation hours after testing, or informal trial and error testing with the risks of under- or over-dosing. However, some alternative methods are discussed.

Minimal Erythema Dose MED Testing

This article describes how to conduct minimal erythema dose (MED) testing in order to determine the lowest dose of ultraviolet radiation that will cause erythema (burning) when administered to an individual.

Ultraviolet radiation (UV) therapy is  sometimes used as a treatment for various common skin conditions, including  psoriasis, acne, and eczema. The ...

The Use of Reverse Phase Protein Arrays (RPPA) to Explore Protein Expression Variation within Individual Renal Cell Cancers

Currently there is no curative treatment for metastatic clear cell renal cell cancer, the commonest variant of the disease. A key factor in this treatment resistance is thought to be the molecular complexity of the disease 1. Targeted therapy such as the tyrosine kinase inhibitor (TKI)-sunitinib have been utilized, but only 40% of patients will respond, with the overwhelming majority of these patients relapsing within 1 year 2. As such the question of intrinsic and acquired resistance in renal cell cancer patients is highly relevant 3.
In order to study resistance to TKIs, with the ultimate goal of developing effective, personalized treatments, sequential tissue after a specific period of targeted therapy is required, an approach which had proved successful in chronic myeloid leukaemia 4. However the application of such a strategy in renal cell carcinoma is complicated by the high level of both inter- and intratumoral heterogeneity, which is a feature of renal cell carcinoma5,6 as well as other solid tumors 7. Intertumoral heterogeneity due to transcriptomic and genetic differences is well established even in patients with similar presentation, stage and grade of tumor. In addition it is clear that there is great morphological (intratumoral) heterogeneity in RCC, which is likely to represent even greater molecular heterogeneity. Detailed mapping and categorization of RCC tumors by combined morphological analysis and Fuhrman grading allows the selection of representative areas for proteomic analysis.
Protein based analysis of RCC8 is attractive due to its widespread availability in pathology laboratories; however, its application can be problematic due to the limited availability of specific antibodies 9. Due to the dot blot nature of the Reverse Phase Protein Arrays (RPPA), antibody specificity must be pre-validated; as such strict quality control of antibodies used is of paramount importance. Despite this limitation the dot blot format does allow assay miniaturization, allowing for the printing of hundreds of samples onto a single nitrocellulose slide. Printed slides can then be analyzed in a similar fashion to Western analysis with the use of target specific primary antibodies and fluorescently labelled secondary antibodies, allowing for multiplexing. Differential protein expression across all the samples on a slide can then be analyzed simultaneously by comparing the relative level of fluorescence in a more cost-effective and high-throughput manner.

The Use of Reverse Phase Protein Arrays RPPA to Explore Protein Expression Variation within Individual Renal Cell Cancers

RPPA enables the protein expression of hundreds of samples, printed on nitrocellulose slides to be interrogated simultaneously, using fluorescently labelled antibodies. This technique has been applied to study the effect of drug treatment heterogeneity within clear cell renal carcinoma.

Currently there is no curative treatment for metastatic clear cell renal cell cancer, the commonest variant of the disease. A key factor in this treatment ...

Accuracy in Dental Medicine, A New Way to Measure Trueness and Precision

Reference scanners are used in dental medicine to verify a lot of procedures. The main interest is to verify impression methods as they serve as a base for dental restorations. The current limitation of many reference scanners is the lack of accuracy scanning large objects like full dental arches, or the limited possibility to assess detailed tooth surfaces. A new reference scanner, based on focus variation scanning technique, was evaluated with regards to highest local and general accuracy. A specific scanning protocol was tested to scan original tooth surface from dental impressions. Also, different model materials were verified. The results showed a high scanning accuracy of the reference scanner with a mean deviation of 5.3 &#177; 1.1 &#181;m for trueness and 1.6 &#177; 0.6 &#181;m for precision in case of full arch scans. Current dental impression methods showed much higher deviations (trueness: 20.4 &#177; 2.2 &#181;m, precision: 12.5 &#177; 2.5 &#181;m) than the internal scanning accuracy of the reference scanner. Smaller objects like single tooth surface can be scanned with an even higher accuracy, enabling the system to assess erosive and abrasive tooth surface loss. The reference scanner can be used to measure differences for a lot of dental research fields. The different magnification levels combined with a high local and general accuracy can be used to assess changes of single teeth or restorations up to full arch changes.

Accuracy is a major demand in dental medicine. To verify accuracy, reference scanners are needed. This article presents a new reference scanner with an adjusted scanning method to acquire a broad variety of dental morphologies with high trueness and precision.

Reference scanners are used in dental medicine to verify a lot of procedures. The main interest is to verify impression methods as they serve as a base ...

Minimal Invasive Surgical Procedure of Inducing Myocardial Infarction in Mice

Myocardial infarction still remains the main cause of death in western countries, despite considerable progress in the stent development area in the last decades. For clarification of the underlying mechanisms and the development of new therapeutic strategies, the availability of valid animal models are mandatory. Since we need new insights into pathomechanisms of cardiovascular diseases under in vivo conditions to combat myocardial infarction, the validity of the animal model is a crucial aspect. However, protection of animals are highly relevant in this context. Therefore, we establish a minimally invasive and simple model of myocardial infarction in mice, which assures a high reproducibility and survival rate of animals. Thus, this models fulfils the requirements of the 3R principle (Replacement, Refinement and Reduction) for animal experiments and assure the scientific information needed for further developing of therapeutical strategies for cardiovascular diseases.

A highly reproducible model for myocardial infarction in mice with minimal invasive manipulations is described. The model can be easily performed, resulting in a high reproducibility and survival rate. Thus, the described model will reduce the number of required animals as requested by the 3R principle (Replacement, Refinement and Reduction).

Myocardial infarction still remains the main cause of death in western countries, despite considerable progress in the stent development area in the last ...

Trabecular Meshwork Response to Pressure Elevation in the Living Human Eye

The mechanical characteristics of the trabecular meshwork (TM) are linked to outflow resistance and intraocular pressure (IOP) regulation. The rationale behind this technique is the direct observation of the mechanical response of the TM to acute IOP elevation. Prior to scanning, IOP is measured at baseline and during IOP elevation. The limbus is scanned by spectral-domain optical coherence tomography at baseline and during IOP elevation (ophthalmodynamometer (ODM) applied at 30 g force). Scans are processed to enhance visualization of the aqueous humor outflow pathway using ImageJ. Vascular landmarks are used to identify corresponding locations in baseline and IOP elevation scan volumes. Schlemm canal (SC) cross-sectional area (SC-CSA) and SC length from anterior to posterior along its long axis are measured manually at 10 locations within a 1 mm segment of SC. Mean inner to outer wall distance (short axis length) is calculated as the area of SC divided by its long axis length. To examine the contribution of adjacent tissues to the effect IOP elevations, measurements are repeated without and with smooth muscle relaxation with instillation of tropicamide. TM migration into SC is resisted by TM stiffness, but is enhanced by the support of its attachment to adjacent smooth muscle within the ciliary body. This technique is the first to measure the living human TM response to pressure elevation in situ under physiological conditions within the human eye.

Trabecular meshwork (TM) migration into Schlemm&#8217;s canal space can be induced by acute pressure elevation by ophthalmodynamometer, and observed by spectral domain optical coherence tomography. The goal of this method is to quantify the morphometric response of the living outflow tract to acute pressure elevation in living tissues in situ.

The mechanical characteristics of the trabecular meshwork (TM) are linked to outflow resistance and intraocular pressure (IOP) regulation. The rationale ...

Generation of Microtumors Using 3D Human Biogel Culture System and Patient-derived Glioblastoma Cells for Kinomic Profiling and Drug Response Testing

The use of patient-derived xenografts for modeling cancers has provided important insight into cancer biology and drug responsiveness. However, they are time consuming, expensive, and labor intensive. To overcome these obstacles, many research groups have turned to spheroid cultures of cancer cells. While useful, tumor spheroids or aggregates do not replicate cell-matrix interactions as found in vivo. As such, three-dimensional (3D) culture approaches utilizing an extracellular matrix scaffold provide a more realistic model system for investigation. Starting from subcutaneous or intracranial xenografts, tumor tissue is dissociated into a single cell suspension akin to cancer stem cell neurospheres. These cells are then embedded into a human-derived extracellular matrix, 3D human biogel, to generate a large number of microtumors. Interestingly, microtumors can be cultured for about a month with high viability and can be used for drug response testing using standard cytotoxicity assays such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and live cell imaging using Calcein-AM. Moreover, they can be analyzed via immunohistochemistry or harvested for molecular profiling, such as array-based high-throughput kinomic profiling, which is detailed here as well. 3D microtumors, thus, represent a versatile high-throughput model system that can more closely replicate in vivo tumor biology than traditional approaches.

Patient-derived xenografts of glioblastoma multiforme can be miniaturized into living microtumors using 3D human biogel culture system. This in vivo-like 3D tumor assay is suitable for drug response testing and molecular profiling, including kinomic analysis.

The use of patient-derived xenografts for modeling cancers has provided important insight into cancer biology and drug responsiveness. However, they are ...

Ultrasound-guided Intracardiac Injection of Human Mesenchymal Stem Cells to Increase Homing to the Intestine for Use in Murine Models of Experimental Inflammatory Bowel Diseases

Crohn&#39;s disease (CD) is a common chronic inflammatory disease of the small and large intestines. Murine and human mesenchymal stem cells (MSCs) have immunosuppressive potential and have been shown to suppress inflammation in mouse models of intestinal inflammation, even though the route of administration can limit their homing and effectiveness 1,3,4,5. Local application of MSCs to colonic injury models has shown greater efficacy at ameliorating inflammation in the colon. However, there is paucity of data on techniques to enhance the localization of human bone marrow-derived MSCs (hMSCs) to the small intestine, the site of inflammation in the SAMP-1/YitFc (SAMP) model of experimental Crohn&#39;s disease. This work describes a novel technique for the ultrasound-guided intracardiac injection of hMSCs in SAMP mice, a well-characterized spontaneous model of chronic intestinal inflammation. Sex- and age-matched, inflammation-free AKR/J (AKR) mice were used as controls. To analyze the biodistribution and the localization, hMSCs were transduced with a lentivirus containing a triple reporter. The triple reporter consisted of firefly luciferase (fl), for bioluminescent imaging; monomeric red fluorescent protein (mrfp), for cell sorting; and truncated herpes simplex virus thymidine kinase (ttk), for positron emission tomography (PET) imaging. The results of this study show that 24 h after the intracardiac administration, hMSCs localize in the small intestine of SAMP mice as opposed to inflammation-free AKR mice. This novel, ultrasound-guided injection of hMSCs in the left ventricle of SAMP mice ensures a high success rate of cell delivery, allowing for the rapid recovery of mice with minimal morbidity and mortality. This technique could be a useful method for the enhanced localization of MSCs in other models of small-intestinal inflammation, such as TNF&#916;RE6. Future studies will determine if the increased localization of hMSCs by intra-arterial delivery can lead to increased therapeutic efficacy.

Murine studies in models of colonic inflammation have demonstrated that a small percentage (1 - 5%) of mesenchymal stem cells (MSC) injected intravenously or intraperitoneally home to the inflamed colon1,2. This study shows that ultrasound-guided intracardiac injections of MSCs result in increased localization to the intestine.

Crohn&#39;s disease (CD) is a common chronic inflammatory disease of the small and large intestines. Murine and human mesenchymal stem cells (MSCs) have ...

Technique and Patient Selection Criteria of Right Anterior Mini-Thoracotomy for Minimal Access Aortic Valve Replacement

Aortic valve stenosis has become the most prevalent valvular heart disease in developed countries, and is due to the aging of these populations. The incidence of the pathology increases with growing age after 65 years. Conventional surgical aortic valve replacement through median sternotomy has been the gold standard of patient care for symptomatic aortic valve stenosis. However, as the risk profile of patients worsens, other therapeutic strategies have been introduced in an attempt to maintain the excellent results obtained by the established surgical treatment. One of these approaches is represented by transcatheter aortic valve implantation. Although the outcomes of high-risk patients undergoing treatment for symptomatic aortic valve stenosis have improved with transcatheter aortic valve replacement, many patients with this condition remain candidates for surgical aortic valve replacement. In order to reduce the surgical trauma in patients who are candidates for surgical aortic valve replacement, minimally invasive approaches have garnered interest during the past decade. Since the introduction of right anterior thoracotomy for aortic valve replacement in 1993, right anterior mini-thoracotomy and upper hemi-sternotomy have become the predominant incisional approaches among cardiac surgeons performing minimal access aortic valve replacement. Beside the location of the incision, the arterial cannulation site represents the second major landmark of minimal access techniques for aortic valve replacement. The two most frequently used arterial cannulation sites include central aortic and peripheral femoral approaches. With the purpose of reducing surgical trauma in these patients, we have opted for a right anterior mini-thoracotomy approach with a central aortic cannulation site. This protocol describes in detail a technique for minimally invasive aortic valve replacement and provides recommendations for patient selection criteria, including cardiac computer tomography measurements. The indications and limitations of this technique, as well as its alternatives, are discussed.

The goal of this protocol is to describe in detail the technique of minimally invasive aortic valve replacement through a right anterior mini-thoracotomy and central aortic cannulation. This technique can potentially enhance patients&#39; comfort and, by reducing post-operative morbidity, promote lowering the length of stay and global costs.

Aortic valve stenosis has become the most prevalent valvular heart disease in developed countries, and is due to the aging of these populations. The ...

A Training and Testing System for Performing Vascular Reconstruction In Vitro

Manual vascular reconstruction training is essential for a beginner surgeon. However, an optimal training system for vascular reconstruction in vitro has yet to be developed. In this study, we introduce an in vitro training and testing system using a magnetic anchoring technique with which a trainee can practice manual vascular reconstruction individually. Additionally, this system can also be used to test the quality of the reconstruction. The described system includes a vascular reconstruction training machine, magnetic tractors, and a magnetic suture puller. In this manuscript, we detail an end-to-end vein anastomosis using porcine right and left iliac veins. To identify the potential damage caused by a magnetic suture puller on the suture, we created three groups with six segments of 4-0 polypropylene sutures each: a control group with no intervention on the polypropylene suture, a group in which the polypropylene suture is manually pulled with sterile gloves 20x, and a magnetic puller group in which the magnetic puller pulled the polypropylene suture 20x. These groups were tested by light microscopy and breaking strength tests, and the effect of reconstruction was assessed. In the light microscopy test, the control group was less likely to be damaged (p &#60; 0.05) and the number of damaged points of the manual group and magnetic puller group were similar (p &#62; 0.05). The results of the breaking strength test were compared across groups and no significant difference was observed (p &#62; 0.05). The end-to-end anastomosis of the porcine iliac veins was successfully performed using this training system, and the reconstructed veins could undergo 2.0 kPa perfusion pressure. Using this training and testing system the trainee can practice manual vascular reconstruction in vitro individually with the aid of magnetic tractors and a magnetic suture puller, and the quality of the reconstruction can be tested.

Here we present a training and testing system where a trainee can complete manual vascular reconstruction in vitro individually using a magnetic anchoring technique. The system can also be used to test the quality of reconstruction.

Manual vascular reconstruction training is essential for a beginner surgeon. However, an optimal training system for vascular reconstruction in vitro has ...

Semi-Minimal Invasive Method to Induce Myocardial Infarction in Rats and the Assessment of Cardiac Function by an Isolated Working Heart System

Myocardial infarction (MI) remains the main contributor to morbidity and mortality worldwide. Therefore, research on this topic is mandatory. An easily and highly reproducible MI induction procedure is required to obtain further insight and better understanding of the underlying pathological changes. This procedure can also be used to evaluate the effects or potency of new and promising treatments (as drugs or interventions) in acute MI, subsequent remodeling and heart failure (HF). After intubation and pre-operative preparation of the animal, an anesthetic protocol with isoflurane was performed, and the surgical procedure was conducted&#160;quickly. Using a minimally invasive approach, the left anterior descending artery (LAD) was located and occluded by a ligature. The occlusion can be performed acutely for subsequent reperfusion (ischemia/reperfusion injury). Alternatively, the vessel can be ligated permanently to investigate the development of chronic MI, remodeling or HF. Despite common pitfalls, the drop-out rates are minimal. Various treatments such as remote ischemic conditioning can be examined for their cardioprotective potential pre-, peri- and post-operatively. The post-operative recovery was quick as the anesthesia was precisely controlled and the duration of the operation was short. Post-operative analgesia was administered for three days. The minimally invasive procedure reduces the risk of infection and inflammation. Furthermore, it facilitates rapid recovery. The &#8220;working heart&#8221; measurements were performed ex vivo and enabled precise control of preload, afterload and flow. This procedure requires specific equipment and training for adequate performance. This manuscript provides a detailed step-by-step introduction for conducting these measurements.

This article presents an efficient method to perform myocardial ischemia and subsequent chronic reperfusion in rats using a minimally invasive approach. In addition, left ventricular hemodynamic function of rats is assessed by echocardiography and isolated working heart methods.&#160;

Myocardial infarction (MI) remains the main contributor to morbidity and mortality worldwide. Therefore, research on this topic is mandatory. An easily ...