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RNase A Inhibits Formation of Neutrophil Extracellular Traps in Subarachnoid Hemorrhage
Conclusion: Neutrophil extracellular trap formation following SAH originates in the ipsilateral SAS of the bleeding site and spreads gradually over time to basal, cortical, and periventricular areas in the parenchyma within 14days. Intravenous RNase application abrogates NET burden significantly in the brain parenchyma, underpinning a potential role in modulation of the innate immune activation after SAH.
Source: Frontiers in Physiology - September 16, 2021 Category: Physiology Source Type: research

Demonstration of Patient-Specific Simulations to Assess Left Atrial Appendage Thrombogenesis Risk
Atrial fibrillation (AF) alters left atrial (LA) hemodynamics, which can lead to thrombosis in the left atrial appendage (LAA), systemic embolism and stroke. A personalized risk-stratification of AF patients for stroke would permit improved balancing of preventive anticoagulation therapies against bleeding risk. We investigated how LA anatomy and function impact LA and LAA hemodynamics, and explored whether patient-specific analysis by computational fluid dynamics (CFD) can predict the risk of LAA thrombosis. We analyzed 4D-CT acquisitions of LA wall motion with an in-house immersed-boundary CFD solver. We considered six p...
Source: Frontiers in Physiology - February 26, 2021 Category: Physiology Source Type: research

Dynamic Arterial Elastance as a Ventriculo-Arterial Coupling Index: An Experimental Animal Study
Dynamic arterial elastance (Eadyn), the ratio between arterial pulse pressure and stroke volume changes during respiration, has been postulated as an index of the coupling between the left ventricle (LV) and the arterial system. We aimed to confirm this hypothesis using the gold-standard for defining LV contractility, afterload, and evaluating ventricular-arterial (VA) coupling and LV efficiency during different loading and contractile experimental conditions. Twelve Yorkshire healthy female pigs submitted to three consecutive stages with two opposite interventions each: changes in afterload (phenylephrine/nitroprusside), ...
Source: Frontiers in Physiology - April 6, 2020 Category: Physiology Source Type: research

Induction of Secretagogue Independent Gastric Acid Secretion via a Novel Aspirin-Activated Pathway
Aspirin has been widely recommended for acute and chronic conditions for over 2,000 years. Either single or repetitive doses are commonly used for analgesic and antipyretic reasons and to prevent heart attacks, stroke, and blood clot formation. Recent studies show that it can also be used chronically to dramatically reduce the risk of a variety of cancers. However, prolonged usage of aspirin can cause severe damage to the mucosal barrier, increasing the risk of ulcer formation and GI-bleeding events. In the present study, we show the effects of acute low-dose aspirin exposure as an active secretagogue-inducing gastric acid...
Source: Frontiers in Physiology - October 9, 2019 Category: Physiology Source Type: research

Reproducibility of a continuous ramp lower body negative pressure protocol for simulating hemorrhage
Abstract Central hypovolemia elicited by application of lower body negative pressure (LBNP) has been used extensively to simulate hemorrhage in human subjects. Traditional LBNP protocols incorporate progressive steps in pressure held for specific time intervals. The aim of this study was to assess the reproducibility of applying continuous LBNP at a constant rate until presyncope to replicate actual bleeding. During two trials (≥4 weeks intervening), LBNP was applied at a rate of 3 mmHg/min in 18 healthy human subjects (12M; 6F) until the onset of presyncopal symptoms. Heart rate (HR), mean arterial pressure (MAP), str...
Source: Physiological Reports - November 25, 2015 Category: Physiology Authors: Victoria L. Kay, Caroline A. Rickards Tags: Original Research Source Type: research

Contribution of neovascularization and intraplaque haemorrhage to atherosclerotic plaque progression and instability
Abstract Atherosclerosis is a continuous pathological process that starts early in life and progresses frequently to unstable plaques. Plaque rupture leads to deleterious consequences such as acute coronary syndrome, stroke and atherothrombosis. The vulnerable lesion has several structural and functional hallmarks that distinguish it from the stable plaque. The unstable plaque has large necrotic core (over 40% plaque volume) composed of cholesterol crystals, cholesterol esters, oxidized lipids, fibrin, erythrocytes and their remnants (haeme, iron, haemoglobin), and dying macrophages. The fibrous cap is thin, depleted of sm...
Source: Acta Physiologica - January 2, 2015 Category: Physiology Authors: D. A. Chistiakov, A. N. Orekhov, Y. V. Bobryshev Tags: Review Source Type: research

Contribution of neovascularization and intra‐plaque haemorrhage to atherosclerotic plaque progression and instability
This article is protected by copyright. All rights reserved.
Source: Acta Physiologica - December 18, 2014 Category: Physiology Authors: Dmitry A. Chistiakov, Alexander N. Orekhov, Yuri V. Bobryshev Tags: Review Article Source Type: research

Are you bleeding? Validation of a machine-learning algorithm for determination of blood volume status: application to remote triage
In conclusion, a machine-learning algorithm developed from low-level physiological signals could reliably distinguish central hypovolemia from exercise, indicating that this device could provide battlefield remote triage capabilities.
Source: Journal of Applied Physiology - March 1, 2014 Category: Physiology Authors: Rickards, C. A., Vyas, N., Ryan, K. L., Ward, K. R., Andre, D., Hurst, G. M., Barrera, C. R., Convertino, V. A. Tags: ARTICLES Source Type: research

Effects of the blood components on the AMPA and NMDA synaptic responses in brain slices in the onset of hemorrhagic stroke.
In this study, we used the technique of on-line monitoring of electrophysiological parameters referred to synaptic activity in piriform cortex of SHR rat slice. We exposed the olfactory cortex slices to diluted autologous blood or its components and compared with effects of ferric chloride. Whole blood exerted a total inhibition of synaptic activity in piriform cortex within first 5 min. Dilution of blood induced prolonged epileptic synaptic activation of NMDA receptors. Blood plasma and fraction of leucocytes induced hyperactivation of neurons transforming to epileptiform discharges. Fraction of red blood cells acted biph...
Source: General Physiology and Biophysics - September 26, 2013 Category: Physiology Authors: Mokrushin AA, Pavlinova LI Tags: Gen Physiol Biophys Source Type: research

Targets of Vascular Protection in Acute Ischemic Stroke Differ in Type 2 Diabetes.
The objective of the current study was to determine the effects of acute manipulation of potential targets for vascular protection (i.e., NFkB, peroxynitrite, and matrix metalloproteinases) on vascular injury and functional outcome in a diabetic model of cerebral ischemia. Ischemia was induced by middle cerebral artery occlusion in control and type 2 diabetic Goto-Kakizaki rats. Treatment groups received a single dose of peroxynitrite decomposition catalyst FeTPPs,a non-specific NFkB inhibitor curcumin, or a broad-spectrum matrix metalloproteinase (MMP) inhibitor minocycline at reperfusion. Post-stroke infarct volume, edem...
Source: American Journal of Physiology. Heart and Circulatory Physiology - January 18, 2013 Category: Physiology Authors: Kelly-Cobbs AI, Prakash R, Li W, Pillai B, Hafez S, Coucha M, Johnson MH, Ogbi SN, Fagan SC, Ergul A Tags: Am J Physiol Heart Circ Physiol Source Type: research