Blood Flow and Vascular Conductance Responses to Dynamic Handgrip Exercise in Hispanic American and Non-Hispanic White Women

Hispanic Americans (HA) are the fastest growing ethnic minority in the United States, with disproportionately higher incidence of obesity, hyperlipidemia and type 2 diabetes compared to their non-Hispanic white (NHW) counterparts. As such, the risk of cardiovascular complications is significantly higher in this population, while the underlying mechanisms remain largely unexplored. Alterations in vascular function occur early in cardiovascular diseases and have not been comprehensively studied in the HA population. Previous studies have demonstrated higher flow-mediated dilation (FMD, an index of resting vascular function) in young HA compared to NHW women. However, whether these differences in vasodilation also occur in response to dynamic exercise remains unknown. PURPOSE: We tested the hypothesis that during increasing intensities of rhythmic handgrip exercise, young, healthy HA women would demonstrate greater forearm blood flow and vascular conductance responses compared to age- and weight-matched NHW women. METHODS: Six HA women (20 ± 2 yr; BMI = 21.45 ± 2.2 kg/m2) and 9 NHW women (20 ± 2 yr; BMI = 21.49 ± 2.2 kg/m2) performed rhythmic handgrip exercise for 3 minutes at 15%, 30%, and 45% of their maximum voluntary contraction (MVC). Each exercise bout was separated by at least 10 minutes of rest. Mean arterial pressure (MAP; finger photoplethysmography), heart rate (ECG), and forearm blood flow (FBF; duplex Doppler ultrasound) was measured at rest and during the last minute of rhythmic exercise. Forearm vascular conductance was calculated as FBF/MAP. RESULTS: Baseline FBF (HA: 53.3 ± 7.6 and NHW: 52.4 ± 11.3 ml/min, mean ± SD, p = 0.87), FVC (HA: 0.64 ± 0.09 and NHW: 0.62 ± 0.16 ml/min/mmHg, p = 0.85), MAP (HA: 83.3 ± 3.18 and NHW: 84.75 ± 6.85 mmHg, p = 0.64), and MVC (HA: 53 ± 13 and NHW: 49 ± 6 kg, p = 0.36) were similar between groups. In response to exercise, both groups demonstrated an intensity dependent increase in FBF (%DFBF during 45%: HA= 437± 90% and NHW= 459 ± 162%, p = 0.76) but no significant difference was found between groups (repeated-measures 2-way ANOVA; interaction effect: p = 0.66, intensity effect: p = 0.0001, ethnicity effect: p = 0.73). Similar to FBF, there was no significant difference in FVC responses between groups (%DFVC 45%: HA= 385 ± 110 and NHW= 393 ± 135, p = 0.91). CONCLUSION: Forearm blood flow and vascular conductance responses during increasing intensities of rhythmic handgrip exercise were not different between HA and NHW women

Forearm Vascular Responses to Rhythmic Handgrip Exercise in Young Healthy Hispanic Men

Hispanic American (HA) men have higher prevalence of Type 2 Diabetes (T2D) when compared to Caucasian American (CA) men (15.3% vs 10.8%). Impaired vascular function is a hallmark of T2D, increasing the risk of cardiovascular morbidity and mortality in this clinical population. However, vascular function in the Hispanic population has not been investigated thoroughly. To date, only two studies have examined the resting flow mediated dilation (FMD) and found a higher FMD in young, healthy, HA adults. Whether exercise-induced reactive hyperemia is preserved in HA adults remains unknown. PURPOSE: We tested the hypothesis that young, healthy HA men would have a higher response in forearm blood flow (FBF) and forearm vascular conductance (FVC) when compared to age-matched CA men. METHODS: In young, healthy HA (n = 7, BMI = 25±2 cm/kg2) and CA men (n = 6, BMI = 24±3), FBF (Duplex doppler ultrasound), heart rate (3-lead ECG), and mean arterial pressure (MAP; finger plethysmography) were measured at rest and during rhythmic handgrip exercise performed for 3 min at 15%, 30%, and 45% of their maximum voluntary contraction (MVC). FVC was calculated by FBF/MAP. Lean muscle mass was measured via dual-energy X-ray absorptiometry (DEXA). RESULTS: Baseline MAP (HA: 85±7 mmHg, CA: 84±7, Mean ± SD, p = 0.85), and MVC (HA: 74 ± 18 kg, CA: 80 ± 17, p = 0.51) were not significantly different between the groups at baseline. Baseline FBF (HA: 83.9±21.9 mL/min, CA: 135.5±39.7, p\u3c0.05) and FVC (HA: 1.0 ± 0.3 mL/min/mmHg, CA: 1.6 ± 0.5, p \u3c 0.05) were significantly greater in CA when compared to HA. In both groups, an intensity dependent increase in FBF and FVC was observed with a significant ethnicity effect between the groups but no significant interaction effect (repeated-measures 2-way ANOVA; interaction effect: p = 0.63, intensity effect: p \u3c 0.01, ethnicity effect: p = 0.006). For example, increase in FVC from baseline (%DFVC) at 45% MVC in HA men was 442 ± 82%, compared to 311 ± 97% CA men, with similar increases in MAP from baseline (45% MVC DMAP; HA: 15 ± 12, CA: 7 ± 5, p = 0.17) or lean muscle mass (HA: 57 ± 4 kg, CA: 61 ± 9 kg, p = 0.41). CONCLUSION: Our preliminary data indicate a higher forearm blood flow and vascular conductance response in response to rhythmic handgrip in HA men compared to matched CA men

Setting upper limits on the strength of periodic gravitational waves from PSR J1939+2134 using the first science data from the GEO 600 and LIGO detectors

Data collected by the GEO 600 and LIGO interferometric gravitational wave detectors during their first observational science run were searched for continuous gravitational waves from the pulsar J1939+2134 at twice its rotation frequency. Two independent analysis methods were used and are demonstrated in this paper: a frequency domain method and a time domain method. Both achieve consistent null results, placing new upper limits on the strength of the pulsar's gravitational wave emission. A model emission mechanism is used to interpret the limits as a constraint on the pulsar's equatorial ellipticity

CMB-S4: Forecasting Constraints on Primordial Gravitational Waves

CMB-S4---the next-generation ground-based cosmic microwave background (CMB) experiment---is set to significantly advance the sensitivity of CMB measurements and enhance our understanding of the origin and evolution of the Universe, from the highest energies at the dawn of time through the growth of structure to the present day. Among the science cases pursued with CMB-S4, the quest for detecting primordial gravitational waves is a central driver of the experimental design. This work details the development of a forecasting framework that includes a power-spectrum-based semi-analytic projection tool, targeted explicitly towards optimizing constraints on the tensor-to-scalar ratio, $r$, in the presence of Galactic foregrounds and gravitational lensing of the CMB. This framework is unique in its direct use of information from the achieved performance of current Stage 2--3 CMB experiments to robustly forecast the science reach of upcoming CMB-polarization endeavors. The methodology allows for rapid iteration over experimental configurations and offers a flexible way to optimize the design of future experiments given a desired scientific goal. To form a closed-loop process, we couple this semi-analytic tool with map-based validation studies, which allow for the injection of additional complexity and verification of our forecasts with several independent analysis methods. We document multiple rounds of forecasts for CMB-S4 using this process and the resulting establishment of the current reference design of the primordial gravitational-wave component of the Stage-4 experiment, optimized to achieve our science goals of detecting primordial gravitational waves for $r > 0.003$ at greater than $5\sigma$, or, in the absence of a detection, of reaching an upper limit of $r < 0.001$ at $95\%$ CL.Comment: 24 pages, 8 figures, 9 tables, submitted to ApJ. arXiv admin note: text overlap with arXiv:1907.0447

CMB-S4: Forecasting Constraints on Primordial Gravitational Waves

Abstract: CMB-S4—the next-generation ground-based cosmic microwave background (CMB) experiment—is set to significantly advance the sensitivity of CMB measurements and enhance our understanding of the origin and evolution of the universe. Among the science cases pursued with CMB-S4, the quest for detecting primordial gravitational waves is a central driver of the experimental design. This work details the development of a forecasting framework that includes a power-spectrum-based semianalytic projection tool, targeted explicitly toward optimizing constraints on the tensor-to-scalar ratio, r, in the presence of Galactic foregrounds and gravitational lensing of the CMB. This framework is unique in its direct use of information from the achieved performance of current Stage 2–3 CMB experiments to robustly forecast the science reach of upcoming CMB-polarization endeavors. The methodology allows for rapid iteration over experimental configurations and offers a flexible way to optimize the design of future experiments, given a desired scientific goal. To form a closed-loop process, we couple this semianalytic tool with map-based validation studies, which allow for the injection of additional complexity and verification of our forecasts with several independent analysis methods. We document multiple rounds of forecasts for CMB-S4 using this process and the resulting establishment of the current reference design of the primordial gravitational-wave component of the Stage-4 experiment, optimized to achieve our science goals of detecting primordial gravitational waves for r > 0.003 at greater than 5σ, or in the absence of a detection, of reaching an upper limit of r < 0.001 at 95% CL

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)