Characterizing Methods of Measuring Flow-Mediated Dilation in the Brachial Artery

Regulation of vascular tone is one of the many important functions of the vascular endothelium. Endothelial dysfunction is a critical early event in the pathogenesis of atherosclerosis and occurs in the absence of angiographic disease. Flow-Mediated Dilation (FMD) is a noninvasive technique commonly used to evaluate endothelium-dependent vasodilation in humans and gauge the health of the cardiovascular system. Reductions in brachial artery FMD have been strongly correlated with disease progression and are predictive of future cardiac events. The flow stimulus for brachial artery FMD occurs as a result of the increased shear stress following deflation of an occlusion cuff around the upper arm. Using 2-dimensional ultrasound, changes in arterial diameter up to 5-minutes following cuff deflation are calculated from baseline image measurements. Along with pulsed Doppler measures of flow velocity through the artery, flow-mediated, endothelium-dependent vasodilation can be assessed. There is debate among investigators, however, about the proper positioning of the occlusion cuff during FMD testing. It is thought that placement of the cuff around the upper arm may not accurately reflect the impact of nitric oxide, a critically important molecule released as a result of the increased shear stress created by the FMD technique. Data suggest that the production of other endogenous metabolites may also contribute to FMD-related changes when positioning the cuff around the upper arm. To overcome the potential influence of such molecules, researchers now suggest that the occlusion cuff be placed below the elbow allowing a more precise estimate of nitric oxide mediated dilation. The purpose of this study is to compare the differences in FMD between the two methodologies of occlusion cuff placement. In addition, this study will determine the method that is easier for ultrasound technicians to perform and will produce a low coefficient of variance between technicians. Ultimately, the results of this study will help in tracking any adverse cardiovascular effects of spaceflight

Racial Differences in Clinical Characteristics, Perceptions and Behaviors, and Psychosocial Impact of Adult Female Acne

Objective: Limited data are available on racial differences in clinical characteristics and burden in adult female acne. The objective was to describe racial differences in clinical characteristics, psychosocial impact, perceptions, behaviors, and treatment satisfaction in facial adult female acne. Design: Cross-sectional, web-based survey. Setting: Diverse sample of United States women. Participants: Women between the ages of 25 and 45 years with facial acne (≥25 visible lesions). Measurements: Outcomes included sociodemographic characteristics, psychosocial impacts, perceptions, behaviors, and treatment satisfaction. Racial differences were evaluated using descriptive statistics and t -test/chi-square analyses. Results: 208 females participated (mean age 35±6 years); 51.4 percent were White/Caucasian and 48.6 percent were non-White/Caucasian women [Black/African American (n=51); Hispanic/Latina (n=23); Asian (n=16); Other (n=ll)]. Age of acne onset (mean 14.8±5 vs. 17.0±8 years, p <0.05) and acne concern occurred earlier (16.6±7 vs. 19.3±9 years, p <0.05) in White/Caucasian than non-White/Caucasian subjects. Facial acne primarily presented on chin (28.0%) and cheeks (30.8%) for White/Caucasian women versus cheeks (58.4%) for non-White/Caucasian women. Non-White/Caucasian women experienced more postinflammatory hyperpigmentation than White/Caucasian women ( p 70%) reported some depression/anxiety symptoms. More White/Caucasian than non-White/Caucasian women were troubled by facial acne (88.8% vs. 76.2%, p <0.05). Lesion clearance was most important to White/Caucasian women (57.9 vs. non-White/Caucasian 31.7%, p <0.001); non-White/Caucasian females focused on postinflammatory hyperpigmentation clearance (41.6% vs. Caucasian 8.4%, p <0.0001). Conclusion: Results highlight racial differences in participant-reported clinical characteristics, attitudes, behaviors, and treatment satisfaction. These findings may inform clinicians about racial differences in facial adult female acne and guide treatment recommendations toward improving care