Centrally Acting Perindopril Attenuates the Exercise Induced Increase in Muscle Sympathetic Nerve Activity during Heavy Dynamic Exercise

Central angiotensin II (Ang II) linked free radical (FR) production scavenges nitric oxide (NO) enabling an increased central sympathetic neural outflow (SNA). The pathophysiological increase in Ang II linked FR production is recognized as a major mechanism involved in neurogenic hypertension. During exercise, there is a physiological increase in Ang II and muscle sympathetic nerve activity (MSNA) in direct relation to increasing exercise intensity. We tested the hypothesis that the exercise induced increase in Ang II linked FR production and MSNA activity during exercise is located within the brain. Six healthy subjects performed three randomly ordered trials of 70° upright back-supported dynamic leg cycling after ingestion of two different lipid soluble Angiotensin converting enzyme inhibitors ((ACEi) Perindopril (PER) - highly lipid soluble; Captopril (CAP) non-lipid soluble)) and/or placebo (PL). Repeated measurements of whole venous blood, MSNA, and mean arterial pressures (MAP) were obtained at rest and during steady-state heavy intensity exercise at heart rates (HR) of 120 bpm (e120). Peripheral venous superoxide concentrations as measured by electron paramagnetic resonance (EPR) were not significantly altered at rest (P≥0.4) and during E120 by the ACE inhibitors (P≥0.07). Likewise, baseline MSNA (PL, 25 ± 1.5 bust/min; CAP, 21 ± 0.7 bust/min; PER, 25 ± 0.7 bust/min) and MAP (PL, 86 ± 2.8 mmHg vs. CAP, 84 ± 2.6 mmHg; PER, 84 ± 0.7 mmHg) were unchanged at rest (P≥0.1; P≥0.8 respectively). However, during E120 central acting PER attenuated the increases in MSNA and MAP, increasing only 15±6% for MAP and 24±8% for MSNA when compared to PL (26 ± 6% MAP; 57±16% MSNA; P\u3c0.05) and CAP (26±4%MAP; 69±13%MSNA P\u3c0.05). From these data we conclude that centrally acting PER attenuated the central increase in the exercise induced Ang II linked free radical production resulting in an increased central NO activity induced reduction in MSNA during heavy intensity dynamic exercise

Antioxidants Attenuate the Exercise Induced Resetting of the Arterial Baroreflex in Healthy Human Subjects: Implications for Exercise Induced Hypertension

Patients with Exercise-induced-Hypertension (EiHT) exhibit exaggerated increases in arterial pressure at the onset of exercise which may prevent EiHT patients from participating in exercise training programs. EiHT is thought to occur due to dysregulated resetting of the arterial baroreflex (ABR). Prior studies in animal models demonstrate that reactive oxygen species (ROS) generated in the brainstem scavenge the sympathoinhibitory function of central Nitric Oxide (NO) and, thereby enable ABR resetting of the operating point (OP) pressure and hypertension. We tested the hypothesis that a centrally and peripherally active antioxidant cocktail (CT; composed of Vitamin E and C with Co-Q10) will attenuate the exercise induced resetting of the ABR‘s centering point (CP) and OP pressures compared to the same exercise intensity performed with a vehicle placebo (PL). Seven healthy human subjects were recruited and performed 700 back-supported semi-recumbent dynamic leg exercise at moderate (HR at 120 beats per minute: e120) and heavy (HR at 150 beats per minute: e150) intensities. Mean arterial pressure (MAP) was continuously recorded using photoplethysmography at the finger, while HR was recorded via a three lead electrocardiogram (ECG). On experimental day 1, subjects were either given the CT or PL 1 hr. (time of peak plasma concentrations) prior to the start of exercise. On a separate experiment day 2, the subjects repeated the same exercise intensity protocol with the other test article (CT or PL) in a randomized repeated measures design. During exercise with the PL ingestion, the CP of the ABR was reset to higher MAPs from rest to e120 (100 ± 3 mm Hg to 121 ± 3 mm Hg, P\u3c0.02) but not e150 (113 ± 3 mm Hg, P=0.15). The absence of resetting at the higher work intensity was likely due to cardiovascular drift (decreasing MAP). Ingestion of the CT prior to the exercise protocols prevented the increase of the CP to higher MAPs from rest to e120 and e150 (rest: 97 ± 3 mm Hg, e120: 106 ± 3 mm Hg, e150: 106 ± 3 mm Hg, P \u3e0.21). Furthermore, the OP- pressure of the ABR was attenuated with CT ingestion compared to PL at e120 (placebo e120: 116 ± 0.8 mm Hg, CT e120: 111 ± 0.8 mm Hg, P = 0.04). These data: (a) confirm that centrally derived ROS contribute to exercise induced ABR resetting; and (b) indicate that EiHT could be treated by ingestion of an anti-oxidant cocktail prior to the start of exercise

Mobile Open Systems Technologies For The Utilities Industries

This chapter considers the provision of mobile computing support for field engineers in the electricity industry. Section 11.2 describes field engineers current working practices and from these derives a set of general requirements for a mobile computing environment to support utilities workers. A key requirement which is identified is the need for field engineers to access real-time multimedia information in the field and it is on this requirement that the remainder of the chapter focuses. Sections 11.3 and 11.4 present a survey of enabling technologies to support distributed systems operating in both local and wide area wireless environments. The impact of these technologies on the provision of mobile computing support is assessed in section 11.5. Section 11.6 describes a software architecture which attempts to address the requirements highlighted in section 11.2 and in particular is designed to support real-time access to data in the field. Finally, section 11.7 considers the degree to which utilities workers requirements can be met by the surveyed technologies and considers the likely impact of remote data access on field engineers working practices

Cerebrovascular Hemodynamics during Concentric and Eccentric Phases of Heavy Resistance Exercise

Rapid and drastic fluctuations in arterial blood pressures, such as those occurring during heavy resistance exercise pose a unique challenge to the maintenance of cerebral perfusion. During high-intensity leg cycling, regulation of cerebral perfusion is reduced by rapid decreases in beat-to-beat fluctuations in blood pressure (diastolic phase) rather than rapid increases (systolic phase). The purpose of this study was to test the hypothesis that rhythmic heavy resistance exercise will similarly impair the regulation of cerebral blood flow during the diastolic phase of beat-to-beat fluctuations in pressure. We studied seven healthy male subjects. Beat-to-beat finger arterial pressures, and middle cerebral artery blood velocity (MCAv) were measured during 10 repetitions (REP) of rhythmic high intensity leg press exercise. Velocities and arterial pressures were evaluated during both the isotonic concentric and eccentric phases of each REP. The Gosling pulsatility index (PI) of MCAv of each REP was calculated as MCAv systolic-MCAv diastolic/MCAv mean. During the concentric phase, systolic arterial pressures progressively increased from REP 1 through REP 10 (P \u3c 0.001), while systolic MCAv was not different across all REPs (P \u3e0.2). Diastolic arterial pressures during the eccentric phase also increased from REP 1 through REP 10 (P = 0.03) however diastolic MCAv decreased during REPs 7-10 compared with REP 2 (P ≤ 0.02). MCAv PI also increased during REP 7-10 compared to REP 2 (P ≤ 0.02). Similar to high-intensity leg cycling, our data suggest that during rhythmic high-intensity leg press exercise, cerebral perfusion is well controlled during periods of rapid increases in blood pressure, but regulation of cerebral perfusion is impaired during the diastolic phase of beat-to-beat fluctuations in pressure

A Bioinformatics-Based Bottom-up Network Reconstruction Approach to Detect Stem Cell-Related Blood Biomarkers of Cardiovascular Damage and Repair

Health Professions - Laboratory/Cellular: 3rd Place (The Ohio State University Denman Undergraduate Research Forum)In peripheral blood there are very rare circulating stem/progenitor cells (CSPCs) with primitive characters and the capacity to differentiate into cardiovascular and other lineages. These cells are promising biomarkers of the organism’s resilience and of its ability to repair injuries. However, because of its complexity, the system of CSPCs has not yet been described by traditional methods in a coherent and simple enough manner to be clinically useful. In response to this limitation, we proposed the CSPC system could be directly assessed by gene expression analysis of peripheral blood mononuclear cells (PBMCs). Initially, 45 genes representing the most used markers of primitivity and differentiation were tested. Among these, 15 genes were organized as a module of the blood transcriptional network which inversely depended on age, blood pressure, and vascular stiffness of donors, as expected from CSPCs. To identify more members of this module, we analyzed 503 Affymetrix microarrays from public databases hybridized with RNA of normal human PBMCs from children (where the primitive genes were better expressed), adults, and burn victims (a response to an injury condition that is preferable to actual cardiovascular patients because of the lack of other risk factors which complicate the interpretation). Normalized data was analyzed by the bioinformatics co-variation method known as “guilt-by-association”. This approach identified 107 potential candidates from data collected from microarrays on healthy children, many having known roles associated with stemness, differentiation, angiogenesis, and/or cardiovascular diseases or repair. A larger study on adults was conducted, as well as studies involving burn injury (that induces massive mobilization of CSPCs) and pregnant women suffering from preeclampsia (a condition due to deficiencies in CSPCs), for comparison. In conclusion, we show how to expand a new, collective, systemic biomarker for the elusive CSPCs that could be used to track their response to injury and to identify patients at risk for developing, or already experiencing, cardiovascular diseases.Arts and Sciences Honors Undergraduate Research ScholarshipAcademic Major: BiologyAcademic Major: Electrical and Computer EngineeringAcademic Major: Neuroscienc

Plant Conservation in a Changing World

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, 201