scholarly journals Oroxylin A, but Not Vasopressin, Ameliorates Cardiac Dysfunction of Endotoxemic Rats

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Chin-Hung Liu ◽  
Mei-Fang Chen ◽  
Tzu-Ling Tseng ◽  
Lih-Geeng Chen ◽  
Jon-Son Kuo ◽  
...  
Keyword(s):  
Cardiac Dysfunction ◽  
Constant Pressure ◽  
Myocardial Dysfunction ◽  
Flow Mode ◽  
Constant Flow ◽  
Oroxylin A ◽  
Beneficial Effects ◽  
Isolated Hearts ◽  
Cardiac Functions ◽  
Coronary Endothelium

The mortality in septic patients with myocardial dysfunction is higher than those without it. Beneficial effects of flavonoid oroxylin A (Oro-A) on endotoxemic hearts were evaluated and compared with that of arginine vasopressin (AVP) which is used to reverse hypotension in septic patients. Endotoxemia in rats was induced by one-injection of lipopolysaccharides (LPS, 10 mg/kg, i.p.), and hearts were isolated 5-hrs or 16-hrs later. Isolated hearts with constant-pressure or constant-flow mode were examined by Langendorff technique. Rate and force of contractions of isolated atrial and ventricular strips were examined by tissue myography. Isolated endotoxemic hearts were characterized by decreased or increased coronary flow (CF) in LPS-treated-for-5hr and LPS-treated-for-16-hr groups, respectively, with decreased inotropy in both groups. Oro-A-perfusion ameliorated while AVP-perfusion worsened the decreased CF and inotropy in both preparations. Oro-A and AVP, however, did not affect diminished force or rate of contraction of atrial and ventricular strips of endotoxemic hearts. Oro-A-induced CF increase was not affected following coronary endothelium-denudation with saponin. These results suggest that Oro-A ameliorates LPS-depressed cardiac functions by increasing CF, leading to positive inotropy. In contrast, AVP aggravates cardiac dysfunction by decreasing CF. Oro-A is a potentially useful candidate for treating endotoxemia complicated with myocardial dysfunction.

scholarly journals Vasoactivity of adenosine in the trout (Oncorhynchus mykiss) coronary system: involvement of nitric oxide and interaction with noradrenaline

1998 ◽  
Vol 201 (22) ◽  
pp. 3075-3083 ◽  
Author(s):  
T Mustafa ◽  
C Agnisola
Keyword(s):  
Nitric Oxide ◽  
Constant Pressure ◽  
Constant Flow ◽  
Nitric Oxide Synthase Inhibitor ◽  
Heart Preparation ◽  
Synthase Inhibitor ◽  
Coronary Endothelium ◽  
Oxide Synthase ◽  
Working Heart

A vasoconstrictory response to adenosine has been reported in coronary rings from fish. Since the reactivity of the large coronary arteries and the microcirculation may differ, the present study was undertaken to determine the role of adenosine in the intact coronary system of trout under constant pressure or flow using an isolated and non-working heart preparation. The involvement of nitric oxide (NO) and the interaction with noradrenaline were also studied. At 10(-9) to 10(-8 )mol l-1, adenosine caused a vasoconstrictory response, whereas between 10(-7) and 10(-5 )mol l-1 the response was predominantly vasodilative. Theophylline abolished both these responses to adenosine. The vasodilation induced by adenosine (at 10(-5 )mol l-1) was significantly reduced when the preparation was perfused under constant-flow than rather under constant-pressure conditions. The nitric oxide synthase inhibitor N-nitro-l-arginine (l-NA, 10(-4 )mol l-1) partially reduced the vasodilation induced by adenosine (at 10(-5 )mol l-1) under constant-pressure but not under constant-flow conditions. Perfusion of the intact coronary system with l-arginine or with adenosine significantly increased the rate of nitrite (NO2-) release, while perfusion with l-NA or theophylline reduced NO2- release. Chemical denudation of the coronary endothelium by CHAPS resulted in the loss of both the l-arginine- and adenosine-mediated vasodilation and the l-arginine-induced increase in the rate of NO2- release. Adenosine (10(-5 )mol l-1) offset and overrode the vasoconstriction induced by 10(-7 )mol l-1 noradrenaline. l-NA inhibited only the adenosine-induced vasodilation but not the ability to offset noradrenaline vasoconstriction, excluding the involvement of NO in the interaction between adenosine and noradrenaline.

Prediction of Poststorage Cardiac Function From Cardioplegic Effluent in an Ex Vivo Porcine Heart Model

2019 ◽  
Vol 2 (4) ◽  
Author(s):  
Benjamin Kappler ◽  
Sjoerd van Tuijl ◽  
Teus J. van Laar ◽  
Dara R. Pabittei ◽  
Marc P. Buijsrogge ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Cardiac Function ◽  
Cardiac Dysfunction ◽  
Ex Vivo ◽  
Heart Function ◽  
Laboratory Animals ◽  
Organ Protection ◽  
Isolated Hearts ◽  
Cardiac Functions ◽  
Proactive Measures

Abstract The use of slaughterhouse-based hearts has advantages over hearts obtained from laboratory animals for preclinical testing. However, slaughterhouse hearts have greater variability in cardiac function; this has resulted in a dispute over their actual reproducibility. This study explores the feasibility of examining the cardioplegic effluent during hypothermic cardiac arrest for the presence of biomarkers to predict poststorage heart function of slaughterhouse hearts. This may enable proactive measures to optimize preservation strategies and improve the initial cardiac performance of slaughterhouse heart experiments. Slaughterhouse pig hearts (n = 9; 420 ± 30 g) were arrested and flushed with an additional liter cardioplegia after 1 h. Effluent samples were examined for ammonia, lactate, troponin, and inorganic phosphate. After 2 h, hearts were hemoreperfused in the ex vivo heart platform PhysioHeart™ to restore physiological cardiac functions and to identify correlations between biomarkers and cardiac output. There was a negative correlation between cardiac output of revived hearts and levels of ammonia (r = −0.865; p = 0.002) and lactate (r = −0.763; p = 0.01). No correlation was found between cardiac output and levels of phosphate (r = −0.553; p = 0.12) and troponin (r = −0.367; p = 0.331). The analysis approach to assess cardioplegic biomarkers was feasible and enabled the estimation of the effectiveness of organ protection and cardiac function before reperfusion. Ammonia is a predictor for cardiac dysfunction. Effluent analysis prior to heart revival can uncover poststorage cardiac dysfunction in isolated hearts and may prevent failed experiments while improving reproducibility and standardization.

Myocardial substrate utilization in perfused hearts isolated from adrenalectomizedcats

1975 ◽  
Vol 228 (6) ◽  
pp. 1656-1662 ◽  
Author(s):  
AC Beardsley ◽  
AM Lefer
Keyword(s):  
Fatty Acid ◽  
Constant Pressure ◽  
Fatty Acid Uptake ◽  
Fatty Acid Transport ◽  
Acid Uptake ◽  
Constant Flow ◽  
Isolated Hearts ◽  
Myocardial Substrate ◽  
Perfused Hearts ◽  
Krebs Henseleit Buffer

Isolated hearts form chronically adrenalectomized cats were perfused with Krebs-Henseleit buffer plus either glucose (10mM) or palmitate (0.4 mM) under various conditions of constant pressure and constant flow. Glucose uptake in adrenalectomizedhearts was not diminished from control values under conditions of constant pressure, constant flow, anoxia, or insulin stimulation. Palmatic acid uptake and oxygen consumption were significantly reduced (P less than 0.02) in adrenalectomized hearts. This diminished fatty acid utilization was also reflected in a significantly lower CO'2 production and incorporation of the palmitate into myocardial triglycerides. The decreased fatty acid uptake by adrenalectomized cat hearts may represent aserious defect in myocardial metabolism since lipids are the major energy substrate forthe heart. Whether the defect occurs in fatty acid transport or activation cannot beelucidated by this study. However, it is unlikely that this defect has a major contributory effect on the dysfunction of adrenalectomized hearts since the myocardium iscabable of using other energy substrates readily.

scholarly journals Differences in ischemia-reperfusion-induced endothelial changes in hearts perfused at constant flow and constant pressure

2008 ◽  
Vol 105 (6) ◽  
pp. 1779-1787 ◽  
Author(s):  
Raja B. Singh ◽  
Vijayan Elimban ◽  
Naranjan S. Dhalla
Keyword(s):  
Cardiac Function ◽  
Constant Pressure ◽  
Contractile Activity ◽  
Ischemia Reperfusion ◽  
No Synthase ◽  
Constant Flow ◽  
Calpain Activity ◽  
Isolated Hearts ◽  
Rat Hearts ◽  
Perfused Hearts

Isolated hearts subjected to ischemia-reperfusion (I/R) exhibit depressed cardiac performance and alterations in subcellular function. Since hearts perfused at constant flow (CF) and constant pressure (CP) show differences in their contractile response to I/R, this study was undertaken to examine mechanisms responsible for these I/R-induced alterations in CF-perfused and CP-perfused hearts. Rat hearts, perfused at CF (10 ml/min) or CP (80 mmHg), were subjected to I/R (30 min global ischemia followed by 60 min reperfusion), and changes in cardiac function as well as sarcolemmal (SL) Na+-K+-ATPase activity, sarcoplasmic reticulum (SR) Ca2+ uptake, and endothelial function were monitored. The I/R-induced depressions in cardiac function, SL Na+-K+-ATPase, and SR Ca2+-uptake activities were greater in hearts perfused at CF than in hearts perfused at CP. In hearts perfused at CF, I/R-induced increase in calpain activity and decrease in nitric oxide (NO) synthase (endothelial NO synthase) protein content in the heart as well as decrease in NO concentration of the perfusate were greater than in hearts perfused at CP. These changes in contractile activity and biochemical parameters due to I/R in hearts perfused at CF were attenuated by treatment with l-arginine, a substrate for NO synthase, while those in hearts perfused at CP were augmented by treatment with NG-nitro-l-arginine methyl ester, an inhibitor of NO synthase. The results indicate that the I/R-induced differences in contractile responses and alterations in subcellular organelles between hearts perfused at CF and CP may partly be attributed to greater endothelial dysfunction in CF-perfused hearts than that in CP-perfused hearts.

Mutual Prediction of Retention Times in a Variety of Operating Modes in Temperature Programmed Gas Chromatography

2017 ◽  
Vol 14 (1) ◽  
pp. 591-597
Author(s):  
Xinglong Zhang ◽  
Li Ze ◽  
Zhengchun Yang ◽  
Ruoxin Wu ◽  
Cairong Gong ◽  
...  
Keyword(s):  
Constant Pressure ◽  
The Other ◽  
Flow Mode ◽  
Constant Flow ◽  
Operating Modes ◽  
Prediction Of Retention ◽  
Novel Method ◽  
Temperature Programmed ◽  
Relative Errors ◽  
Prediction Of Retention Times

In this paper, a new concept of calibration hold-up time was defined. On the basis of the concept, a novel method was proposed to predict retention times in temperature programmed (isothermal) under constant flow and constant pressure mode each other, and the method also researched in simultaneous pressure and temperature programmed. The prediction results show that average relative errors are 1.33% (0.64%) in temperature programmed (isothermal) under constant pressure mode by using isothermal dates in constant flow mode, and the other way around, average relative errors are 0.62% (−0.62%). For simultaneous pressure and temperature programmed, retention times were predicted by using isothermal dates in constant flow and constant pressure mode, average relative errors are −0.24% and −0.16%; and retention times were predicted by using isothermal dates directly, average relative errors are −0.62%.

Analysis for Coupling Relationship of Oil Pocket under Eccentric Load in Hydrostatic Worktable

2012 ◽  
Vol 233 ◽  
pp. 28-34
Author(s):  
Jian Hua Zhao ◽  
Dian Rong Gao
Keyword(s):  
Machine Tools ◽  
Constant Pressure ◽  
Numerical Control ◽  
Flow Mode ◽  
Work Piece ◽  
Constant Flow ◽  
Oil Film ◽  
Coupling Relationship ◽  
Performance Indexes ◽  
Oil Pockets

The oil pocket of the hydrostatic worktable in the modern heavy numerical control (NC) machine tools is designed under the circumstance that the working load acts equally on the oil pockets. But when the work piece is out of the rotary center of the worktable, the working load acts unequally on the oil pockets, and then the performance indexes for the oil pockets, such as acting force, oil film thickness, hydraulic damping, rated flow, are different. Based on the eccentric working load, under the circumstance that the oil pocket provides the fluid oil with constant pressure and constant flow mode, the coupling relationship between the oil pockets is analyzed, and the expression and the relatively bar graphics are presented. To achieve the machining quality and to prevent against the totally worn-out of the machine tools, it is best to adjust one oil pocket in order to keep the oil film of all oil pockets at the same thickness. While one oil pocket is adjusted, the oil pockets are intercoupling, and then the performance indexes change synchronously. According to the characteristics of the oil pocket in the hydrostatic worktable, the expression on the coupling relationship for the oil pocket is derived, then the performance indexes are analyzed qualitatively and the curves are plotted. The proposed research analyzed qualitatively the coupling relationship on the performance indexes for the constant pressure and the constant flow oil pockets separately in the worktable. It can improve the design efficiency and the accuracy with the help of the computer programs, and provides the reference for the practical engineering.

An Introduction to the Ansaldo GT36 Constant Pressure Sequential Combustor

2017 ◽  
Author(s):  
Douglas A. Pennell ◽  
Mirko R. Bothien ◽  
Andrea Ciani ◽  
Victor Granet ◽  
Ghislain Singla ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Constant Pressure ◽  
Energy Market ◽  
Combustion System ◽  
Turbine Engine ◽  
Beneficial Effects ◽  
Fuel Flexibility ◽  
Temperature Ranges ◽  
System Robustness

This paper introduces and presents validation of the Constant Pressure Sequential Combustion system (denoted CPSC), a second generation concept developed for and applied to the new Ansaldo GT36 H-class gas turbine combustors. It has evolved from the well-established sequential burner technology applied to all current GT26 and GT24 gas turbines, and contains all architectural improvements implemented since original inception of this engine frame in 1994, with beneficial effects on the operation turndown, fuel flexibility, on the overall system robustness, and featuring the required aspects to stay competitive in the present day energy market. The applied air and fuel management therefore facilitate emission and dynamics control at both the extremely high and low firing temperature ranges required for existing and future Ansaldo gas turbine engine classes.

scholarly journals Paeoniflorin and Hydroxysafflor Yellow A in Xuebijing Injection Attenuate Sepsis-Induced Cardiac Dysfunction and Inhibit Proinflammatory Cytokine Production

2021 ◽  
Vol 11 ◽  
Author(s):  
Xin-Tong Wang ◽  
Zhen Peng ◽  
Ying-Ying An ◽  
Ting Shang ◽  
Guangxu Xiao ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Cardiac Dysfunction ◽  
Cardiac Tissue ◽  
Myocardial Dysfunction ◽  
Cecal Ligation ◽  
Hydroxysafflor Yellow A ◽  
Sepsis Management ◽  
Xuebijing Injection

Sepsis-induced myocardial dysfunction is a major contributor to the poor outcomes of septic shock. As an add-on with conventional sepsis management for over 15 years, the effect of Xuebijing injection (XBJ) on the sepsis-induced myocardial dysfunction was not well understood. The material basis of Xuebijing injection (XBJ) in managing infections and infection-related complications remains to be defined. A murine cecal ligation and puncture (CLP) model and cardiomyocytes in vitro culture were adopted to study the influence of XBJ on infection-induced cardiac dysfunction. XBJ significantly improved the survival of septic-mice and rescued cardiac dysfunction in vivo. RNA-seq revealed XBJ attenuated the expression of proinflammatory cytokines and related signalings in the heart which was further confirmed on the mRNA and protein levels. Xuebijing also protected cardiomyocytes from LPS-induced mitochondrial calcium ion overload and reduced the LPS-induced ROS production in cardiomyocytes. The therapeutic effect of XBJ was mediated by the combination of paeoniflorin and hydroxysafflor yellow A (HSYA) (C0127-2). C0127-2 improved the survival of septic mice, protected their cardiac function and cardiomyocytes while balancing gene expression in cytokine-storm-related signalings, such as TNF-α and NF-κB. In summary, Paeoniflorin and HSYA are key active compounds in XBJ for managing sepsis, protecting cardiac function, and controlling inflammation in the cardiac tissue partially by limiting the production of IL-6, IL-1β, and CXCL2.

Assessment of intracranial dynamics in hydrocephalus: effects of viscoelasticity on the outcome of infusion tests

2013 ◽  
Vol 119 (6) ◽  
pp. 1511-1519 ◽  
Author(s):  
Simone Bottan ◽  
Marianne Schmid Daners ◽  
Diane de Zelicourt ◽  
Norina Fellner ◽  
Dimos Poulikakos ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Standard Method ◽  
Constant Pressure ◽  
Constant Flow ◽  
Infusion Test ◽  
Computational Framework ◽  
Bolus Infusion ◽  
Phantom Model ◽  
Identification Approach ◽  
Infusion Method

Object The treatment of hydrocephalus requires insight into the intracranial dynamics in the patient. Resistance to CSF outflow (R0) is a clinically obtainable parameter of intracranial fluid dynamics that quantifies the apparent resistance to CSF absorption. It is used as a criterion for the selection of shunt candidates and serves as an indicator of shunt performance. The R0 is obtained clinically by performing 1 of 3 infusion tests: constant flow, constant pressure, or bolus infusion. Among these, the bolus infusion method has the shortest examination times and provides the shortest time of exposure of patients to artificially increased intracranial pressure (ICP) levels. However, for unknown reasons, the bolus infusion method systematically underestimates the R0. Here, the authors have tested and verified the hypothesis that this underestimation is due to lack of accounting for viscoelasticity of the craniospinal space in the calculation of the R0. Methods The authors developed a phantom model of the human craniospinal space in order to reproduce in vivo pressure-volume (PV) relationships during infusion testing. The phantom model followed the Marmarou exponential PV equation and also included a viscoelastic response to volume changes. Parameters of intracranial fluid dynamics, such as the R0, could be controlled and set independently. In addition to the phantom model, the authors designed a computational framework for virtual infusion testing in which viscoelasticity can be turned on or off in a controlled manner. Constant flow, constant pressure, and bolus infusion tests were performed on the phantom model, as well as on the virtual computational platform, using standard clinical protocols. Values for the R0 were derived from each infusion test by using both a standard method based on the Marmarou PV equation and a novel method based on a system identification approach that takes into account viscoelastic behavior. Results Experiments with the phantom model confirmed clinical observations that both the constant flow and constant pressure infusion tests, but not the bolus infusion test, yield correct R0 values when they are determined with the standard method according to Marmarou. Equivalent results were obtained using the computational framework. When the novel system identification approach was used to determine the R0, all of the 3 infusion tests yielded correct values for the R0. Conclusions The authors' investigations demonstrate that intracranial dynamics have a substantial viscoelastic component. When this viscoelastic component is taken into account in calculations, the R0, is no longer underestimated in the bolus infusion test.

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