Angiotensin II and VEGF are Involved in Angiogenesis Induced by Short-Term Exercise Training

Results from our laboratory have suggested a pathway involving angiotensin II type 1 (AT1) receptors and vascular endothelial growth factor (VEGF) in angiogenesis induced by electrical stimulation. The present study investigated if similar mechanisms underlie the angiogenesis induced by short-term exercise training. Seven days before training and throughout the training period, male Sprague-Dawley rats received either captopril or losartan in their drinking water. Rats underwent a 3-day treadmill training protocol. The tibialis anterior and gastrocnemius muscles were harvested under anesthesia and lightly fixed in formalin (vessel density) or frozen in liquid nitrogen (VEGF expression). In controls, treadmill training resulted in a significant increase in vessel density in all muscles studied. However, the angiogenesis induced by exercise was completely blocked by either losartan or captopril. Western blot analysis showed that VEGF expression was increased in the exercised control group, and both losartan and captopril blocked this increase. The role of VEGF was directly confirmed using a VEGF-neutralizing antibody. These results confirm the role of angiotensin II and VEGF in angiogenesis induced by exercise

Development and Analysis of the Automated Object Reentry Survival Analysis Tool Parametric Study Wrapper

The NASA Orbital Debris Program Office (ODPO) studies all aspects of spacecraft end-of-life and orbital debris measurement, modeling, and mitigation. The reentry safety group within the ODPO uses the Object Reentry Survival Analysis Tool (ORSAT) to calculate the casualty risk due to reentry of spacecraft and other types of orbital debris. ORSAT models spacecraft as a collection of fragments that break apart from the parent object at a pre-defined breakup altitude. It then calculates the trajectory and aero-heating of these fragments to determine which fragments are completely destroyed and which survive to the ground and pose a risk to human population. Because of the historically high computational cost of these calculations, many simplifying assumptions have been made in the traditional calculation and analysis process used by the ODPO, some of which have been shown by recent research by the ODPO and others to be incorrect. Improvements to the ORSAT code and advancements in computer technology have vastly decreased the programs processing time, and have allowed the ODPO to develop a capability for large-scale parametric studies and Monte Carlo reentry simulations that can aid in both the initial spacecraft design and provide more detailed and accurate risk analysis to spacecraft operators

Rawls\u27s Theory Of Justice A Necessary Extension To Environmentalism

John Rawls‟s stated intergenerational justice scheme, known as the just-savings principle, does not include an institutional concern for the environment and is therefore incomplete and incapable of maintaining meaningfully just relations between generations. The theory‟s emphasis on economic theory and capital accumulation demonstrates a misinterpretation of environmental issues and concerns as well as their underlying causes and repercussions. This lapse in Rawls‟s intergenerational scheme exposes flaws in his larger theory of justice by leaving the stability of society in question and placing arbitrary burdens on generations and peoples without institutional recourse. However, by supplementing justice as fairness (JAF) with Rawls‟s other writings, such as The Law of Peoples, a more satisfactory outline for justice between generations can be achieved and a more comprehensive scheme of intergenerational justice can be incorporated into Rawls‟s theory of justic

An Assessment of Ankle Stability in Elite Rugby Union

The aim of the study was to assess dynamic postural stability and the perceived chronic ankle instability (CAI) in a population of elite rugby union players, and to examine the relationship between these two measures. Thirty-three professional rugby players undertook the Cumberland Ankle Instability Tool (CAIT) as well as dynamic postural control testing using the Y-balance test (YBT). Significant differences of between-limb performance in the posterolateral direction on the YBT were seen for those athletes reporting perceived CAI in one or both ankles when compared to no perceived CAI (p = 0.00). These findings suggest poorer lateral dynamic postural control at the ankle in those athletes who identify as having CAI. By administering these tools together, the study suggests that we are able to identify athletes who may benefit from targeted intervention programs to address compromised ankle stability and potential CAI progression

Composite microstructures and climate change

posterDevelop mathematical models to better understand the changes in sea ice as it pertains to global climate. Compare Diffusion Limited Aggregates (DLA) and Electrorheological (ER) fluids to sea ice microstructures

Gender-Specific Protection from Microvessel Rarefaction in Female Hypertensive Rats

Epidemiologic studies reveal that women have a significantly lower age-adjusted morbidity and mortality from cardiovascular disease than men, suggesting that gender is a cardiovascular disease risk factor. The mechanism of the “gender protection” is unknown. In this study, we investigated the microvascular remodeling in reduced renal mass plus a high salt (4.0% NaCl) diet model of hypertension (RRM + HS). We hypothesized that women would be protected from the increase in blood pressure and from the microvascular rarefaction associated with RRM + HS hypertension. Studies were designed to determine whether female rats were less susceptible to changes in microvessel density during RRM + HS. Microvessel density was measured in male and female low salt (0.4% LS) sham-operated controls (Sham + LS) and after 3 days or 4 weeks of RRM + HS hypertension. The microcirculation of hind limb (medial and lateral gastrocnemius, plantaris, soleus) muscles was visualized using rhodamine-labeled Griffonia simplicifolia I lectin. Tissue sections were examined by videomicroscopy and microvessel density was determined by quantitative stereology. As shown previously, mean arterial pressure increased to 160 ± 8 mm Hg and microvessel density decreased (\u3e30% decrease in all beds) in male RRM + HS. In contrast, mean arterial pressure of female RRM + HS rats was modestly increased from 101 ± 2 to 118 ± 4 mm Hg. Despite previous results showing a reduction in microvessel density of both normotensive and hypertensive male rats on a high salt diet, microvessel density of female RRM + HS rats was not reduced at either time. These results suggest that gender protection in the RRM rat extends beyond an attenuation of the increase in pressure to an immunity from microvascular rarefaction

Distinct roles of estrone and estradiol in endothelial colony-forming cells.

Our current understanding of the relationship between estrogen and human endothelial colony-forming cell (hECFC) function is based almost exclusively on studies investigating estradiol action at nuclear estrogen receptors. In the current study the hypothesis was tested that the less potent estrogen receptor agonist, estrone, affects hECFC proliferation, migration, secretion, and tube formation in a way that is unique from that of estradiol. The relationship between the estrogens, estradiol and estrone, is clinically important, particularly in postmenopausal women where estradiol levels wane and estrone becomes the predominant estrogen. Cultured hECFCs from peripheral blood mononuclear cell fractions were treated with concentrations of estradiol and estrone ranging from 1 nM to 1 μM separately and in combination. Following treatment, proliferation, migration, ability to attract other hECFCs (autocrine secretion), and ability to enhance endothelial cell tube formation (tubulogenesis) were tested. Functional assays revealed unique, concentration-dependent physiological effects of estrone and estradiol. Estradiol exposure resulted in increased hECFC proliferation, migration, secretion of chemoattractant, and enhancement of tube formation as expected. As with estradiol, hECFC secretion of chemoattractant increased significantly with each increase in estrone exposure. Estrone treatment produced a biphasic, concentration-dependent relationship with proliferation and tube formation and relatively no effect on hECFC migration at any concentration. The quantitative relationship between the effects of estrone and estradiol and each hECFC function was analyzed. The extent to which estrone was similar in effect to that of estradiol was dependent on both the concentrations of estradiol and estrone and the hECFC function measured. Interestingly, when the two estrogens were present, differing ratios resulted in unique functional responses. hECFCs that were treated with combinations of estrone and estradiol with high estrone to estradiol ratios showed decreased proliferative capacity. Conversely, hECFCs that were treated with combinations that were relatively high in estradiol, showed increased proliferative capacity. Cells that were treated with estrone and estradiol in equal concentrations showed an attenuated proliferative response that was decreased compared to the proliferation that either estrone or estradiol produced when they were present alone. This co-inhibitory relationship, which has not been previously reported, challenges the prevailing understanding of estrone as solely a weak agonist at estrogen receptors. This study provides evidence that estrone signaling is distinct from that of estradiol and that further investigation of estrone\u27s mechanism of action and the biological effect may provide important insight into understanding the dysfunction and decreased number of hECFCs, and the resulting cardiovascular disease risk observed clinically in menopausal women and women undergoing hormone replacement therapy