Publications by authors named "Ninette Shenouda"

Increased arterial wave reflections can increase left ventricular wasted pressure effort (WPE) and cardiovascular disease risk. Naturally menstruating women experience fluctuations in sex hormones with known cardioprotective effects. We sought to determine whether hormonal fluctuations alter arterial hemodynamics or wave reflections, and thereby WPE, or contribute to sex differences.

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Vascular dysfunction, marked by lower endothelial function and increased aortic stiffness, is a nontraditional risk factor that precedes the development of cardiovascular disease (CVD). However, the age at which these changes in vascular function occur in women and the degree to which reproductive hormones mediate these changes has not been characterized. Women free from major disease were enrolled across the adult life span (aged 18-70 yr, = 140).

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Mitochondria-derived oxidative stress has been implicated in vascular and skeletal muscle abnormalities in chronic kidney disease (CKD). The purpose of this study was to investigate the effects of a mitochondria-targeted ubiquinol (MitoQ) on vascular function and exercise capacity in CKD. In this randomized controlled trial, 18 patients with CKD (means ± SE, age: 62 ± 3 yr and estimated glomerular filtration rate: 45 ± 3 mL/min/1.

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Aging increases arterial stiffness and wave reflections that augment left ventricular wasted pressure effort (WPE). A single bout of exercise may be effective at acutely reducing WPE via reductions in arterial wave reflections. In young adults (YA) acute aerobic exercise decreases, whereas handgrip increases, wave reflections.

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Endogenous sex hormone concentrations vary between healthy naturally menstruating (non-OCP) and oral contraceptive pill-using (OCP) women, as well as across cycles. The aim of this study was to investigate potential differences in concentrations of inflammatory cytokine interleukin-6 (IL-6) and vasoconstrictive substance endothelin-1 (ET-1) and measures of vascular function among relatively lower- and higher-hormone phases of non-OCP and OCP women. Concentrations of estrogen, progesterone, IL-6, and ET-1 and measures of vascular function were collected in 22 women (22 ± 1 yr, OCP: = 12) during the early follicular (EF, ≤5 days of menstruation onset) and early luteal (EL, 4 ± 2 days postovulation) phases of non-OCP subjects and were compared to the placebo pill (PP, ≤5 days of PP onset) and active pill (AP, ≤5 days of highest-dose AP) phases of OCP subjects.

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Following aerobic exercise, sustained vasodilation and concomitant reductions in total peripheral resistance (TPR) result in a reduction in blood pressure that is maintained for two or more hours. However, the time course for postexercise changes in reflected wave amplitude and other indices of pulsatile load on the left ventricle have not been thoroughly described. Therefore, we tested the hypothesis that reflected wave amplitude is reduced beyond an hour after cycling at 60% V̇o for 60 min.

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Central aortic pressure waveforms contain valuable prognostic information in addition to central systolic pressure. Using pressure-flow relations, wave separation analysis can be used to decompose aortic pressure waveforms into forward- (Pf) and backward-traveling (Pb) components. Reflection magnitude, the ratio of pressure amplitudes (RM = Pb/Pf), is a predictor of heart failure and all-cause mortality.

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Introduction: Low-flow mediated constriction (L-FMC) has emerged as a valuable and complementary measure of flow-mediated dilation (FMD) for assessing endothelial function non-invasively. High dietary sodium has been shown to impair FMD independent of changes in blood pressure (BP), but its effects on L-FMC are unknown.

Purpose: To test the hypothesis that high dietary sodium would attenuate brachial artery L-FMC in salt-resistant adults.

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Carotid artery longitudinal wall motion (CALM) exhibits reduced magnitude in older adults and in individuals with chronic diseases, although longitudinal data are lacking to indicate how changes in CALM might develop over time. Therefore, the aim of this study was to investigate the effect of exercise training in healthy men on CALM using a retrospective design. Carotid ultrasound data were analysed from two previous studies in which men performed 12 wk of moderate-intensity continuous exercise training (n = 9), sprint-interval training (n = 7), higher-repetition resistance exercise training (n = 15) or lower-repetition resistance exercise training (n = 15).

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Sex hormone concentrations differ between men, premenopausal women with natural menstrual cycles (NAT), and premenopausal women using oral contraceptive pills (OCP), as well as across menstrual or OCP phases. This study sought to investigate how differences in sex hormones, particularly estradiol, between men and women and across cycle phases might influence brachial artery endothelial function. Fifty-three healthy adults (22 ± 3 yr, 20 men, 15 NAT women, and 18 second-, third-, or fourth-generation OCP women) underwent assessments of sex hormones and endothelial [flow-mediated dilation (FMD) test] and smooth muscle [nitroglycerin (NTG) test] function.

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New Findings: What is the central question of this study? What is the acute brachial artery endothelial function response to sprint interval exercise and are there sex-based differences? What is the main finding and its importance? Brachial artery endothelial function did not change in either men or women following an acute session of SIT consisting of 3 × 20 s 'all-out' cycling sprints. Our findings suggest this low-volume protocol may not be sufficient to induce functional changes in the brachial artery of sedentary, but otherwise healthy adults.

Abstract: Sprint interval training (SIT) is a potent metabolic stimulus, but studies examining its acute effects on brachial artery endothelial function are limited.

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Arterial stiffness is associated with increased cardiovascular disease risk. Previous sex-based investigations of local and central stiffness report inconsistent findings and have not controlled for menstrual cycle phase in women. There is also evidence that sex hormones influence the vasculature, but their impact on arterial stiffness across a natural menstrual (NAT) or oral contraceptive pill (OCP) cycle has been understudied.

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Moderate-intensity continuous training (MICT) improves peripheral artery function in healthy adults, a phenomenon that reverses as continued training induces structural remodeling. Sprint interval training (SIT) elicits physiological adaptations similar to MICT, despite a lower exercise volume and time commitment; however, its effect on peripheral artery function and structure is largely unexplored. We compared peripheral artery responses to 12 wk of MICT and SIT in sedentary, healthy men (age = 27 ± 8 yr).

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Many commercial ultrasound systems are now including automated analysis packages for the determination of carotid intima-media thickness (cIMT); however, details regarding their algorithms and methodology are not published. Few studies have compared their accuracy and reliability with previously established automated software, and those that have were in asymptomatic adults. Therefore, this study compared cIMT measures from a fully automated ultrasound edge-tracking software (EchoPAC PC, Version 110.

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