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Oxygen delivery

Marty D Spranger, Jasdeep Kaur, Javier A Sala-Mercado, Abhinav C Krishnan, Rania Abu-Hamdah, Alberto Alvarez, Tiago M Machado, Robert A Augustyniak, Donal S O'Leary
Increases in myocardial oxygen consumption during exercise mainly occur via increases in coronary blood flow (CBF) as cardiac oxygen extraction is high even at rest. However, sympathetic coronary constrictor tone can limit increases in CBF. Increased sympathetic nerve activity (SNA) during exercise is, in part, a function of muscle metaboreflex activation (MMA). As SNA is heightened even at rest in subjects with hypertension (HTN), we tested whether HTN causes exaggerated coronary vasoconstriction during mild treadmill exercise with MMA (elicited by reducing hindlimb blood flow by ~60%) thereby limiting increases in CBF and ventricular performance...
October 21, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Maria Elisabeth Moreira, Ana Paula Esteves Pereira, Saint Clair Gomes Junior, Ruth Guinsburg, Maria Fernanda Branco de Almeida, Silvana Granado Gama, Maria do Carmo Leal
BACKGROUND: Approximately 5-10 % of newborns require some form of resuscitationupon delivery; several factors, such as maternal abnormal conditions, gestational age and type of delivery could be responsible for this trend. This study aimed to describe the factors associated with the need for positive pressure ventilation (PPV) via a mask or endotracheal tube and the use of supplemental O2 in newborns with a gestational age greater than 34 weeks in Brazil. METHODS: We performed a cross-sectional study and obtained data from the Birth in Brazil Survey...
October 17, 2016: Reproductive Health
Cosmo Godino, Antonio Colombo, Alberto Margonato
Heart rate is an established prognostic marker for longevity and is an important contributor in the pathophysiology of various cardiovascular diseases, including ischemic heart disease and heart failure. Most ischemic episodes are triggered by an increase in heart rate, which causes an imbalance between myocardial oxygen delivery and consumption. In addition, increased heart rate is a modifiable risk factor for chronic heart failure. Ivabradine, an inhibitor of If ion channels, is an approved second-line anti-ischemic drug for the treatment of angina...
October 21, 2016: Clinical Drug Investigation
Bryan M Corbett, Charles O'Connell, Mallory A Boutin, Nabil I Fatayerji, Charles W Sauer
BACKGROUND Methylergonovine is an ergot alkaloid used to treat post-partum hemorrhage secondary to uterine atony. Mistaking methylergonovine for vitamin K with accidental administration to the neonate is a rare iatrogenic illness occurring almost exclusively in the delivery room setting. Complications of ergot alkaloids in neonates include respiratory depression, seizures, and death. CASE REPORT A term infant was inadvertently given 0.1 mg of methylergonovine intramuscularly in the right thigh. The error was only noted when the vial of medication was scanned, after administration, identifying it as methylergonovine rather than vitamin K...
October 21, 2016: American Journal of Case Reports
Victor M Niemeijer, Ruud F Spee, Thijs Schoots, Pieter F F Wijn, Hareld M Kemps
The extent and speed of transient skeletal muscle deoxygenation during exercise onset in chronic heart failure (CHF) patients is related to impairments of local O2 delivery and utilization. This study examined the physiological background of submaximal exercise performance in 19 moderately impaired CHF patients (Weber class A, B, and C) compared with 19 matched healthy control (HC) subjects by measuring skeletal muscle oxygenation (SmO2) changes during cycling exercise. All subjects performed two subsequent moderate-intensity 6-minute exercise tests (bout 1 and 2) with measurements of pulmonary oxygen uptake kinetics, and SmO2 using near infrared (NIR) spatially resolved spectroscopy (SRS) at the vastus lateralis for determination of absolute oxygenation values, amplitudes, kinetics (mean response time for onset), and deoxygenation overshoot characteristics...
October 7, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Matthias Jacob, Daniel Chappell, Bernhard F Becker
Oxygen delivery to cells is the basic prerequisite of life. Within the human body, an ingenious oxygen delivery system, comprising steps of convection and diffusion from the upper airways via the lungs and the cardiovascular system to the microvascular area, bridges the gap between oxygen in the outside airspace and the interstitial space around the cells. However, the complexity of this evolutionary development makes us prone to pathophysiological problems. While those problems related to respiration and macrohemodynamics have already been successfully addressed by modern medicine, the pathophysiology of the microcirculation is still often a closed book in daily practice...
October 21, 2016: Critical Care: the Official Journal of the Critical Care Forum
Esther Peters, Bülent Ergin, Asli Kandil, Ebru Gurel-Gurevin, Andrea van Elsas, Rosalinde Masereeuw, Peter Pickkers, Can Ince
Two small clinical trials indicated that administration of bovine intestinal alkaline phosphatase (AP) improves renal function in critically ill patients with sepsis-associated acute kidney injury (AKI), for which the mechanism of action is not completely understood. Here, we investigated the effects of a newly developed human recombinant AP (recAP) on renal oxygenation and hemodynamics and prevention of kidney damage and inflammation in two in vivo AKI models. To induce AKI, male Wistar rats (n=18) were subjected to renal ischemia (30min) and reperfusion (I/R), or sham-operated...
October 16, 2016: Toxicology and Applied Pharmacology
Thomas Breuer, Nima Hatam, Benjamin Grabiger, Gernot Marx, Bradley J Behnke, Joachim Weis, Ruedger Kopp, Ghislaine Gayan-Ramirez, Norbert Zoremba, Christian S Bruells
Perioperative necessity of deep sedation is inevitably associated with diaphragmatic inactivation. This study investigated 1) the feasibility of a new phrenic nerve stimulation method allowing early diaphragmatic activation even in deep sedation and, 2) metabolic changes within the diaphragm during mechanical ventilation compared to artificial activity. 12 piglets were separated into 2 groups. One group was mechanically ventilated for 12 hrs (CMV) and in the second group both phrenic nerves were stimulated via pacer wires inserted near the phrenic nerves to mimic spontaneous breathing (STIM)...
October 19, 2016: Scientific Reports
Sree Vamsee Chintapalli, Srinivas Jayanthi, Prema L Mallipeddi, Ravi Kumar Gundampati, Suresh Kumar Thallapuranam Krishnaswamy, Damian B van Rossum, Andriy Anishkin, Sean H Adams
Previous research has indicated that long-chain fatty acids can bind myoglobin (Mb) in an oxygen dependent manner. This suggests that Oxy-Mb may play an important role in fuel delivery in Mb-rich muscle fibers (e.g., type I fibers and cardiomyocytes), and raises the possibility that Mb also serves as an acylcarnitine binding protein. We report for the first time the putative interaction and affinity characteristics for different chain lengths of both fatty acids and acylcarnitines with Oxy-Mb using molecular dynamic simulations and isothermal titration calorimetry experiments...
October 7, 2016: Journal of Biological Chemistry
Samuel A Einstein, Bradley P Weegman, Meri T Firpo, Klearchos Papas, Michael Garwood
Techniques to monitor the oxygen partial pressure (pO<sub>2</sub>) within implanted tissue-engineered grafts (TEGs) are critically necessary for TEG development, but current methods are invasive and inaccurate. In this study, we investigated an accurate and noninvasive technique to monitor TEG pO<sub>2</sub> utilizing proton (<sup>1</sup>H) or fluorine (<sup>19</sup>F) magnetic resonance spectroscopy (MRS) relaxometry. The value of the spin-lattice relaxation rate constant (R<sub>1</sub>) of some biocompatible compounds is sensitive to dissolved oxygen (and temperature), while insensitive to other external factors...
October 19, 2016: Tissue Engineering. Part C, Methods
Sungmun Lee, Yeu-Chun Kim, Ji-Ho Park
Reactive oxygen species (ROS) play an important role in the development of inflammatory bowel diseases. Superoxide dismutase (SOD) has a great therapeutic potential by scavenging superoxide that is one of ROS; however, in vivo application is limited especially when it is orally administered. SOD is easily degraded in vivo by the harsh conditions of gastrointestinal tract. Here, we design a zein-alginate based oral drug delivery system that protects SOD from the harsh conditions of gastrointestinal tract and releases it in the environment of the small intestine...
October 15, 2016: International Journal of Pharmaceutics
Angel Paternina-Caicedo, Jezid Miranda, Ghada Bourjeily, Andrew Levinson, Carmelo Dueñas, Camilo Bello Muñoz, José A Rojas-Suarez
BACKGROUND: Every day, about 830 women die worldwide from preventable causes related to pregnancy and childbirth. Obstetric early-warning scores have been proposed as a potential tool to reduce maternal morbidity and mortality, based upon the identification of predetermined abnormal values in the vital signs or laboratory parameters, to generate a rapid and effective medical response. Several early-warning scores have been developed for obstetrical patients, but the majority are the result of a clinical consensus rather than statistical analyses of clinical outcome measures (i...
October 14, 2016: American Journal of Obstetrics and Gynecology
Cori R Atlin, Christoph Haller, Osami Honjo, Anusha Jegatheeswaran, Glen S Van Arsdell
BACKGROUND: Size mismatch between body and a systemic-to-pulmonary shunt can result in excessive pulmonary blood flow, compromising systemic oxygen delivery. Previously reported techniques to mechanically restrict shunt flow lack precision and reproducibility. We developed a formula for shunt banding and assessed its efficacy and reproducibility by in vitro and clinical measurements. METHODS: Formulas to determine diameter reduction, length of banding, and effect on the ratio of pulmonary blood flow (Qp) to systemic blood flow (Qs) were established...
November 2016: Journal of Thoracic and Cardiovascular Surgery
Jenny M Pedersen, Yoo-Sik Shim, Vaibhav Hans, Martin B Phillips, Jeffrey M Macdonald, Glenn Walker, Melvin E Andersen, Harvey J Clewell, Miyoung Yoon
Accurate prediction of metabolism is a significant outstanding challenge in toxicology. The best predictions are based on experimental data from in vitro systems using primary hepatocytes. The predictivity of the primary hepatocyte-based culture systems, however, is still limited due to well-known phenotypic instability and rapid decline of metabolic competence within a few hours. Dynamic flow bioreactors for three-dimensional cell cultures are thought to be better at recapitulating tissue microenvironments and show potential to improve in vivo extrapolations of chemical or drug toxicity based on in vitro test results...
2016: Frontiers in Bioengineering and Biotechnology
Anton Chechushkov, Natalia Zaitseva, Elena Vorontsova, Petr Kozhin, Elena Menshchikova, Vyacheslav Shkurupiy
AIMS: Linear dextrans are often proposed as drug delivery systems with milder adverse effects and lower effective drug concentrations. Linear dextrans are polysaccharides that can potentially be used to load macrophages with drugs to transport them to a site of inflammation. Recently, it was reported that dextrans may exert a protective effect vis-à-vis drug cytotoxicity and during wound healing. The aim of the current work was to evaluate molecular mechanisms of action of dextrans that may be relevant to the cytoprotective effects...
October 13, 2016: Life Sciences
J H Kang, B H Choi, K M Moon, Y M Park, K H Yang, J H Ryu, C W Chu
It is well known that the quality of organs retrieved from brain-dead donors (DBDs) is better than those retrieved from circulatory death donors. However, in situations of organ retrieval from marginal DBDs, who are unstable despite intensive care, transplantation outcomes are not good. Organ ischemia is the most important determining factor in decreased organ quality in circulatory death donors and in some DBDs. Extracorporeal membrane oxygenation (ECMO) for management of DBDs can be an emergency countermeasure...
September 2016: Transplantation Proceedings
Peter B Terry, Richard J Traystman
Oxygen delivery and carbon dioxide removal being critical to cell survival, mammals have developed collateral vascular and ventilation systems to ensure tissue viability. Collateral ventilation, defined as ventilation of alveoli via pathways that bypass normal airways, is present in humans and many other species. The presence of collateral ventilation can be beneficial in certain disease states, while its relative absence can predispose to other diseases. These well defined anatomical pathways contribute little to ventilation in normal humans, but modulate ventilation perfusion imbalance in a variety of diseases including obstructive diseases such as asthma and emphysema...
October 14, 2016: Annals of the American Thoracic Society
Michael Welter, Heiko Rieger
Tumor vasculature, the blood vessel network supplying a growing tumor with nutrients such as oxygen or glucose, is in many respects different from the hierarchically organized arterio-venous blood vessel network in normal tissues. Angiogenesis (the formation of new blood vessels), vessel cooption (the integration of existing blood vessels into the tumor vasculature), and vessel regression remodel the healthy vascular network into a tumor-specific vasculature. Integrative models, based on detailed experimental data and physical laws, implement, in silico, the complex interplay of molecular pathways, cell proliferation, migration, and death, tissue microenvironment, mechanical and hydrodynamic forces, and the fine structure of the host tissue vasculature...
2016: Advances in Experimental Medicine and Biology
Gabriele Saccone, Vincenzo Berghella
OBJECTIVE:  To evaluate the effectiveness of antenatal corticosteroids given at ≥34 weeks' gestation. DESIGN:  Systematic review with meta-analysis. DATA SOURCES:  Electronic databases were searched from their inception to February 2016. ELIGIBILITY CRITERIA FOR STUDY SELECTION:  Randomized clinical trials comparing antenatal corticosteroids with placebo or no treatment in women with a singleton pregnancy at ≥34 weeks' gestation...
October 12, 2016: BMJ: British Medical Journal
Janelle Yu, Suzanne Lu, Ann-Marie McLaren, Julie A Perry, Karen M Cross
Diabetic foot ulcers (DFUs) are a significant problem in an aging population. 15% of diabetics develop a DFU over their lifetime, which can lead to potential amputation. The 5-year survival rate after amputation is 31%, which is greater than the lifetime risk of mortality from cancer. Topical oxygen is a promising technique for the adjunctive therapy of chronic wounds including DFUs, but few controlled studies exist to support its clinical adoption. The aim of this study was to compare a portable topical oxygen delivery system in patients with non-healing DFUs to standard best practice...
October 12, 2016: Wound Repair and Regeneration
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