tbuckley/cabot-search huggingface dataset:
Mathematical model of the changes in heart rate elicited by vagal stimulation.
Authors: FDexter, M NLevy, YRudy
Journal: Circulation Research (1989)

We developed a mathematical model of the underlying cellular mechanisms responsible for the changes in sinus cycle length (SCL) elicited by vagal stimulation in intact animals. The model incorporated a stimulation-mediated depletion of the releasable pool of acetylcholine (ACh) in the nerve endings, the in vitro reaction kinetics of acetylcholinesterase, and the electrical activity of a pacemaker cell with six membrane ionic currents. SCL increased linearly with the frequency of simulated vagal stimulation, as it does in animal experiments, because the concentration of ACh in the neuroeffector junction [( ACh]) saturated as the frequency of stimulation was increased and because SCL increased geometrically in response to increases in [ACh]. The dependence of SCL on the timing of vagal stimulation in the cardiac cycle resulted, in part, from the dependence of [ACh] on SCL. Simulated vagal stimulation entrained the sinus node because the rate of activation and inactivation of ACh-activated K+ channels depend...
Abstract 11605: Association Between HDL-P Subfractions and Metabolic Syndrome, Inflammation and Insulin Resistance
Authors: Giuliano Generoso, Isabela M Bensenor, Raul D Santos, Alessandra C Goulart, Steven R Jones, James D Otvos, Michael J Blaha, Peter P Toth, Paulo A Lotufo, Marcio S Bittencourt
Journal: Circulation (2018)

Introduction: High-density lipoprotein particles (HDL-P) can be measured by total particle number and also particle number of component subfractions which may have variable effects on atheroscleros...
Sodium-lithium exchange and sodium-proton exchange are mediated by the same transport system in sarcolemmal vesicles from bovine superior mesenteric artery.
Authors: A MKahn, J CAllen, E JCragoe, HShelat
Journal: Circulation Research (1989)

Several laboratories have reported that Na+-Li+ countertransport activities are increased in red blood cells from patients with essential hypertension. It has been proposed that the activity of this red blood cell transport system might reflect the activity of a similar system in vascular smooth muscle. We previously demonstrated Na+-Li+ exchange in sarcolemmal vesicles from canine artery and proposed that this transport function might be mediated by the Na+-H+ exchanger. In the present studies, however, we were unable to demonstrate Na+-Li+ countertransport in canine red blood cells. Since bovine red blood cells have a vigorous Na+-Li+ exchanger and we previously demonstrated Na+-H+ exchange in sarcolemmal vesicles from bovine artery, we wished to determine whether bovine sarcolemmal vesicles mediate Na+-Li+ exchange and whether this transport function is mediated via the Na+-H+ exchanger. We found that an outwardly directed proton or Li+ gradient stimulated 22Na+ uptake in sarcolemmal vesicles from bovi...
Ventricular intramural and epicardial potential distributions during ventricular activation and repolarization in the intact dog.
Authors: M SSpach, R CBarr
Journal: Circulation Research (1975)

Ventricular intramural and epicardial potential distributions were measured during normal excitation and repolarization in intact dogs. Potential distributions were chosen because they can be unambiguously measured, are useful in understanding the shapes of wave forms at many specific sites, and provide a direct measure of repolarization. Unipolar wave forms were recorded from intramural and epicardial electrodes and converted into potential distributions. Well-known shapes of wave forms recorded at the inner and outer layers of the ventricles as well as peak-to-peak voltages were shown by the potential distributions to be determined primarily by superposition effects of distant excitation waves. These effects were most prominent before epicardial breakthrough and then receded during the last half of the QRS complex. However, the potential distributions became more complex as excitation waves merged, collided, and terminated. During terminal depolarization, there were scattered positive repolarization pot...
Gestational diabetes mellitus.
Authors: L Edouard, R F Dyck
Journal: BMJ (1993)

A fine needle on a syringe was introduced through the cyst wall, and air under pressure pushed the syringe barrel outwards.At this point the surgeon and the anaesthetist realised that this pharyngocele had resulted from the inflated cuffof the laryngeal mask used.It was more prominent through the head having been turned to the opposite side.The "diagnostic" puncture of the cuff resulted in a slow deflation, which eventually necessitated the replacement of the mask owing to the development of laryngeal spasm.The surgeon was relieved ofthe need for further investigation of the swelling.
Idiopathic restrictive cardiomyopathy.
Authors: R JSiegel, P KShah, M CFishbein
Journal: Circulation (1984)

This report details the clinical, hemodynamic, and morphologic data from four patients 59 to 77 years old (mean 66) with a primary restrictive cardiomyopathy. All patients had symptoms of congestive heart failure, jugular venous distention, and murmurs of mitral and tricuspid regurgitation. Four patients required pacemakers, three for the brady-tachy syndrome and one for complete heart block. Chest x-ray demonstrated cardiomegaly in all four patients and pulmonary congestion and/or pleural effusions in three. Echocardiographic examination documented left atrial enlargement in all patients, along with normal left ventricular internal dimensions. Global left ventricular systolic function was normal in all, and left and right ventricular filling pressures were elevated and similar in three. A dip and plateau pattern was present in the pressure tracings of two of three patients. Unlike previous reports of restrictive cardiomyopathy, in our four patients there was no specific morphologic cause noted at necrops...
Intramural hemorrhage and endothelial changes in atherosclerotic coronary artery after repetitive episodes of spasm in x-ray-irradiated hypercholesterolemic pigs.
Authors: KNagasawa, HTomoike, YHayashi, AYamada, TYamamoto, MNakamura
Journal: Circulation Research (1989)

To assess whether coronary spasm affects the progression of atherosclerosis and results in evolution of myocardial infarction, the role of coronary spasm on the fine structure of conduit coronary arteries was studied morphologically. Gottingen miniature pigs were fed a semisynthetic diet containing 2% cholesterol and 1.1% sodium cholate. One month after being on this diet, the pigs were anesthetized and the endothelium of a branch of the left coronary artery was denuded using a balloon catheter. X-ray irradiation in a dose of 1,500 rad was given twice selectively to the area denuded, after 4 and 5 months of cholesterol feeding. Five months after endothelial denudation, transient (group A) and repetitive episodes (group B) of coronary spasm were provoked by single and periodic (five times every 5 minutes) intracoronary injections of serotonin (10 micrograms/kg/injection), respectively. The extent of spasm by serotonin at the previously denuded site was 84 +/- 4% (n = 4) and 90 +/- 5% (n = 6) narrowing in g...
Intelligent prediction of RBC demand in trauma patients using decision tree methods
Authors: Yan-Nan Feng, Zhen-Hua Xu, Jun-Ting Liu, Xiao-Lin Sun, De-Qing Wang, Yang Yu
Journal: Military Medical Research (2021)

The vital signs of trauma patients are complex and changeable, and the prediction of blood transfusion demand mainly depends on doctors' experience and trauma scoring system; therefore, it cannot be accurately predicted. In this study, a machine learning decision tree algorithm [classification and regression tree (CRT) and eXtreme gradient boosting (XGBoost)] was proposed for the demand prediction of traumatic blood transfusion to provide technical support for doctors.A total of 1371 trauma patients who were diverted to the Emergency Department of the First Medical Center of Chinese PLA General Hospital from January 2014 to January 2018 were collected from an emergency trauma database. The vital signs, laboratory examination parameters and blood transfusion volume were used as variables, and the non-invasive parameters and all (non-invasive + invasive) parameters were used to construct an intelligent prediction model for red blood cell (RBC) demand by logistic regression (LR), CRT and XGBoost. The prediction accuracy of the model was compared with the area under the curve (AUC).For non-invasive parameters, the LR method was the best, with an AUC of 0.72 [95% confidence interval (CI) 0.657-0.775], which was higher than the CRT (AUC 0.69, 95% CI 0.633-0.751) and the XGBoost (AUC 0.71, 95% CI 0.654-0.756, P < 0.05). The trauma location and shock index are important prediction parameters. For all the prediction parameters, XGBoost was the best, with an AUC of 0.94 (95% CI 0.893-0.981), which was higher than the LR (AUC 0.80, 95% CI 0.744-0.850) and the CRT (AUC 0.82, 95% CI 0.779-0.853, P < 0.05). Haematocrit (Hct) is an important prediction parameter.The classification performance of the intelligent prediction model of red blood cell transfusion in trauma patients constructed by the decision tree algorithm is not inferior to that of the traditional LR method. It can be used as a technical support to assist doctors to make rapid and accurate blood transfusion decisions in emergency rescue environment, so as to improve the success rate of patient treatment.
"Prorenin" in human plasma?
Authors: J ESealey, J HLaragh
Journal: Circulation Research (1975)

An increase in plasma renin activity was demonstrated in plasma from normal subjects and most patients with essential hypertension after prolonged storage of the plasma at -20 degrees C. No change in renin substrate concentration was observed after storage for 12 months, and the rate of angiotensin generation during incubation with a fixed amount of added human renin was not increased. It therefore seems unlikely that the observed increase in renin activity was due to changes in plasma activators or inhibitors. The data are consistent with the activation of an inactive form of renin, tentatively called prorenin in normal subjects averaged from 1 to 2 ng/ml/hr, and did not change during sodium deprivation. However, three of four patients studied who had low-renin essential hypertension secreted abnormally large amounts of prorenin in response to sodium depletion. In these patients, subsequent sodium administration was associated with a return of prorenin to baseline levels.
Endothelin in human congestive heart failure.
Authors: C MWei, ALerman, R JRodeheffer, C GMcGregor, R RBrandt, SWright, D MHeublein, P CKao, W DEdwards, J CBurnett
Journal: Circulation (1994)

BACKGROUNDAlthough recent investigations report the elevation of plasma endothelin (ET) in congestive heart failure (CHF), it remains unclear if this elevation is that of the biologically active peptide ET-1 or of its precursor big-ET. Furthermore, it is unclear if such elevation is associated with increased myocardial ET and if the molecular form from cardiac tissue is altered ET. Last, it remains to be established whether circulating ET is increased at the earliest stage of CHF in patients with asymptomatic left ventricular dysfunction and correlates with the magnitude of ventricular dysfunction.METHODS AND RESULTSThe present study was designed to investigate concentrations and molecular forms of ET in plasma and cardiac tissue in healthy subjects and CHF patients with New York Heart Association (NYHA) class I through IV using cardiac radionuclide angiogram, cardiac myocardial biopsy, radioimmunoassay, gel permeation chromatography (GPC), and immunohistochemical staining (IHCS). Plasma ET was increased ...
Evaluation of the role of polymorphonuclear leukocytes on contractile function in myocardial reperfusion injury. Evidence for plasma-mediated leukocyte activation.
Authors: S MShandelya, PKuppusamy, M LWeisfeldt, J LZweier
Journal: Circulation (1993)

BACKGROUNDIt has been hypothesized that chemotaxis and activation of polymorphonuclear leukocytes (PMNs) occur upon reperfusion of ischemic myocardium. Questions remain, however, regarding the mechanisms by which PMNs are chemotaxed and activated and how this process causes contractile failure.METHODS AND RESULTSStudies were performed in an isolated rat heart model in which the effects of isolated cellular or humoral factors could be studied. Isolated rat hearts were perfused by the method of Langendorff, subjected to 20 minutes of global ischemia, and reperfused with perfusate alone or with perfusate containing PMNs, plasma, PMNs plus plasma, or PMNs plus inactivated plasma (preheated to 56 degrees C for 30 minutes to denature complement) (n = 10 in each group). Left ventricular developed pressure (LVDP) was measured during 1 minute of preischemic control infusion and on reflow after a 20-minute period of global ischemia. Additional measurements of free-radical generation were also performed on the coron...
Dual effect of thrombin on voltage-dependent Ca2+ channels of portal vein smooth muscle cells.
Authors: ABaron, GLoirand, PPacaud, CMironneau, JMironneau
Journal: Circulation Research (1993)

Thrombin induces a number of physiological responses in several types of cells. To determine the action of thrombin in the vein, the electrophysiological and mechanical effects of thrombin were studied in rat portal vein smooth muscle cells. Ca2+ channel currents were recorded using the whole-cell patch-clamp technique. Thrombin had both inhibitory and stimulatory effects on the Ca2+ channel current. The inhibitory effect was reversed on washout of thrombin, whereas the stimulatory effect was maintained after thrombin was removed. Thrombin (1 unit/ml) produced a reversible decrease of 27.3 +/- 3.3% (n = 12) in the current amplitude and a sustained increase of 71.2 +/- 12.9% (n = 20). The thrombin-induced inhibition of Ca2+ channel current was blocked by the thrombin inhibitor hirudin and by the protease inhibitor leupeptin. The stimulatory effect of thrombin was inhibited by hirudin, by intracellular application of guanosine 5'-O-(beta-thio)diphosphate, and by antiphophatidylinositide antibodies but not b...
Limitation of myocardial infarct expansion by reperfusion independent of myocardial salvage.
Authors: J SHochman, HChoo
Journal: Circulation (1987)

Very early reperfusion after coronary occlusion can reduce infarct size and preserve left ventricular function. Whether later reperfusion is of benefit is unclear. We studied the effect of very early reperfusion with myocardial salvage and late reperfusion without myocardial salvage on infarct expansion and aneurysm formation. Sixty-eight rats underwent left coronary artery ligation and were randomized to 30 min reperfusion, 2 hr reperfusion, or permanent coronary artery ligation. The animals were killed and the hearts examined at 2 weeks. Thirty minute reperfusion reduced infarct size, extent of transmurality, and infarct expansion. Two hour reperfusion reduced neither infarct size nor transmurality but inhibited infarct expansion. The results of this study in the rat preparation suggest a beneficial effect of late reperfusion on infarct expansion independent of myocardial salvage. If these results are confirmed in human beings, the period after myocardial infarction during which a patient can be con...
False Positive Phencyclidine Results Caused by Venlafaxine
Authors: PATRICIO MOLERO SANTOS , M.D., PILAR LÓPEZ-GARCÍA , M.D., Ph.D., JAVIER SCHLATTER NAVARRO , M.D., Ph.D., ANTONIO SEVA FERNÁNDEZ , M.D., Ph.D., BELÉN SÁDABA , M.D., Ph.D., JORGE PLA VIDAL , M.D., Ph.D.
Journal: American Journal of Psychiatry (2007)
Contractile state of the left ventricle in man as evaluated from end-systolic pressure-volume relations.
Authors: WGrossman, EBraunwald, TMann, L PMcLaurin, L HGreen
Journal: Circulation (1977)

End-systolic pressure (PES), volume (VES), wall tension (TES) and circumference (CES) of the human left ventricle were studied at cardiac catheterization in 24 subjects with varying degrees of left ventricular dysfunction. Acute alterations in systolic load consistently resulted in changes in VES and CES, with a smaller volume and circumference characterizing the lower systolic load in each subject. End systolic pressure-volume lines were constructed by plotting PES against VES at the higher and lower systolic load in each subject. The slope of the resultant lines was considerably steeper for normal than for poorly contractile left ventricles. Vo, the volume axis intercept of the line (i.e., the theoretical VES at PES = O) was significantly smaller for normal than for poorly contractile ventricles. Similar findings were noted for Co, the theoretic end-systolic circumference at zero end-systolic ventricular wall tension. Post-extrasystolic potentiation resulted in decreased VES and CES with no change in PE...
Diabetes Is the Main Factor Accounting for the High Ferritin Levels Detected in Chronic Hepatitis C Virus Infection
Authors: Albert Lecube, Cristina Hernández, Joan Genescà, Rafael Simó
Journal: Diabetes Care (2005)

After reading the comments by Sebastiani et al. (1) on our article (2) regarding the association between diabetes and ferritin in chronic hepatitis C virus (HCV) infection, we would like to make the following comments. In contrast to our results, the authors did not find any relationship between serum ferritin levels and glucose abnormalities in HCV-infected patients. However, it should be noted that the number of patients included in our …
Hirudin in acute myocardial infarction. Safety report from the Thrombolysis and Thrombin Inhibition in Myocardial Infarction (TIMI) 9A Trial.
Authors: E MAntman
Journal: Circulation (1994)

BACKGROUNDThe Thrombolysis and Thrombin Inhibition in Myocardial Infarction (TIMI) 9A trial compared the efficacy and safety of intravenous hirudin with heparin as adjunctive therapy to thrombolysis and aspirin in patients with acute myocardial infarction. The primary safety end point was the occurrence of major hemorrhage or anaphylaxis.METHODS AND RESULTSBased on experience in phase II trials, TIMI 9A used a hirudin bolus of 0.6 mg/kg followed by a fixed-dose 96-hour infusion of 0.2 mg/kg per hour. A modified weight-adjusted heparin regimen was used (5000-U bolus and infusion of 1000 U/h for patients   or = 80 kg) with titration to a target activated partial thromboplastin time (aPTT) of 60 to 90 seconds. Because rates of hemorrhage in both treatment arms were higher than expected, randomization was suspended in TIMI 9A after 757 patients had been enrolled. Intracranial hemorrhage occurred in 1.7% of patients treated with hirudin and 1.9% of those treated with heparin (P...
Left ventricular end-systolic volume as the major determinant of survival after recovery from myocardial infarction.
Authors: H DWhite, R MNorris, M ABrown, P WBrandt, R MWhitlock, C JWild
Journal: Circulation (1987)

Impairment of left ventricular function is the major predictor of mortality after acute myocardial infarction, but it is not known whether this is best described by ejection fraction or by end-systolic or end-diastolic volume. We measured volumes, ejection fractions, and severity of coronary arterial occlusions and stenoses in 605 male patients under 60 years of age at 1 to 2 months after a first (n = 443) or recurrent (n = 162) myocardial infarction and followed these patients for a mean of 78 months for survivors (range 15 to 165 months). There were 101 cardiac deaths, 71 (70%) of which were sudden (instantaneous or found dead). Multivariate analysis with log rank testing and the Cox proportional hazards model showed that end-systolic volume (chi 2 = 82.9) had greater predictive value for survival than end-diastolic volume (chi 2 = 59.0) or ejection fraction (chi 2 = 46.6), whereas stepwise analysis showed that once the relationship between survival and end-systolic volume had been fitted, there was no ...
Histamine-induced coronary spasm in regions of intimal thickening in miniature pigs: roles of serum cholesterol and spontaneous or induced intimal thickening.
Authors: KEgashira, HTomoike, YYamamoto, AYamada, YHayashi, MNakamura
Journal: Circulation (1986)

The pathogenesis of histamine-induced coronary spasm was examined angiographically and morphometrically in Gottingen miniature pigs. In five of 36 consecutive pigs that were 4 to 5 months of age, coronary spasm was provoked by the intracoronary administration of histamine, and the left coronary arteries were examined histologically without endothelial denudation (group 1). Endothelial balloon denudation of the major branch of the left coronary artery was performed in 31 of 36 pigs and five died during the procedure. The remaining 26 pigs were randomly allotted to one of two groups, one fed a cholesterol-supplemented (group 2, n = 13) and one fed a regular low-cholesterol diet (group 3, n = 13). After 3 months, serum cholesterol increased significantly from 57 +/- 6 to 222 +/- 27 mg/dl (p less than .01) in group 2, but remained unchanged (48 +/- 5 to 55 +/- 6 mg/dl) in group 3. Percent narrowing of the coronary diameter induced by 10 micrograms/kg ic histamine after administration of the H2 blocker cimetid...
Observations on blood viscosity changes after acute myocardial infarction.
Authors: K MJan, SChien, J TBigger
Journal: Circulation (1975)

Serial blood rheologic measurements were made in 25 patients with acute myocardial infarction; measurements included blood and plasma viscosities, hematological data and plasma protein concentrations. The blood viscosity was elevated on admission and for more than 21 days after acute myocardial infarction. However, the cause of the elevated viscosity was changed as a function of time after acute myocardial infarction. During the first three days after admission, the high blood viscosity was mainly attributable to high hematocrit values. Thereafter, the hematocrit fell, but blood viscosity remained high. High blood viscosity after the first three days of acute myocardial infarction can be correlated with increases in plasma viscosity and red cell aggregation, which in turn are explained by elevations of alpha 2 globulin and fibrinogen concentrations. Patients with higher blood viscosity on admission had a significantly higher incidence of complications, i.e., shock, thromboembolism and left ventricular fai...
Concern About the Use of Venlafaxine to Treat Vasomotor Symptoms—Reply
Authors: Hadine Joffe, Andrea Z. LaCroix, Lee Cohen
Journal: JAMA Internal Medicine (2015)

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