tbuckley/cabot-search huggingface dataset:
Relation between myocardial function and expression of sarcoplasmic reticulum Ca(2+)-ATPase in failing and nonfailing human myocardium.
Authors: GHasenfuss, HReinecke, RStuder, MMeyer, BPieske, JHoltz, CHolubarsch, HPosival, HJust, HDrexler
Journal: Circulation Research (1994)

Expression of sarcoplasmic reticulum (SR) Ca(2+)-ATPase was shown to be reduced in failing human myocardium. The functional relevance of this finding, however, is not known. We investigated the relation between myocardial function and protein levels of SR Ca(2+)-ATPase in nonfailing human myocardium (8 muscle strips from 4 hearts) and in myocardium from end-stage failing hearts with dilated (10 muscle strips from 9 hearts) or ischemic (7 muscle strips from 5 hearts) cardiomyopathy. Myocardial function was evaluated by the force-frequency relation in isometrically contracting muscle strip preparations (37 degrees C, 30 to 180 min-1). In nonfailing myocardium, twitch tension rose with increasing rates of stimulation and was 76% higher at 120 min-1 compared with 30 min-1 (P < .02). In failing myocardium, there was no significant increase in average tension at stimulation rates above 30 min-1. At 120 min-1, twitch tension was decreased by 59% (P < .05) in dilated cardiomyopathy and 76% (P < .05) in ischemic c...
Sympathetic modulation of the relation between ventricular repolarization and cycle length.
Authors: AZaza, GMalfatto, P JSchwartz
Journal: Circulation Research (1991)

Sympathetic influences on ventricular repolarization are not yet fully elucidated, despite their relevance to arrhythmogenesis. The sympathetic control of repolarization, measured from an endocardial monophasic action potential duration (APD) and from the QT interval, was investigated in 24 anesthetized cats. The effects of right and left stellectomy and of subsequent bilateral stellectomy or beta-blockade on the relation between APD (or QT) and cycle length (CL) at steady state, and on the kinetics of adaptation of APD to a sudden change in cycle length were studied separately. Steady-state APD/CL (or QT/CL) relations were obtained by atrial pacing at different cycle lengths. The kinetics of APD adaptation were evaluated for a sudden decrease of approximately 100 msec in pacing cycle length. The steady-state APD/CL (QT/CL) relation was fitted by the hyperbolic function APD = CL/[(a. CL) + b]. From this, two parameters were computed: 1) 1/a, that is, APD (QT) extrapolated at infinite cycle length (APDmax ...
The independent value of exercise thallium scintigraphy to physicians.
Authors: MHlatky, EBotvinick, BBrundage
Journal: Circulation (1982)

To determine the effect of exercise myocardial scintigraphy with thallium-201 on diagnostic accuracy and the need for coronary angiography, consecutive patients with a variety of clinical presentations were identified. Clinical summaries, including a detailed history, physical examination, and complete data from a standard treadmill exercise test, were presented to 91 cardiologists. The cardiologists assessed the probability of coronary disease and the need for coronary angiography. They were then presented the results of thallium scintigraphy and revised their assessments if warranted. Scintigraphy significantly increased the cardiologists' diagnostic accuracy beyond that attained with other clinical information (p less than 0.0001). The change in accuracy varied from + 4% to + 20% in different patient groups, and was greatest in patients with atypical angina and a positive exercise ECG. Ratings of the need for coronary angiography changed from -13% to +21% in different patient groups. We conclude that e...
Electrophysiological mechanisms in a canine model of erythromycin-associated long QT syndrome.
Authors: MRubart, M LPressler, H PPride, D PZipes
Journal: Circulation (1993)

BACKGROUNDErythromycin is known to prolong ventricular repolarization and has been associated with the occurrence of torsades de pointes. In this study, we have investigated potential mechanisms in vivo and in vitro for induction of an acquired long QT syndrome by erythromycin.METHODS AND RESULTSVentricular electrograms and endocardial monophasic action potentials were recorded in anesthetized open-chest dogs before and after administration of 40 to 120 mg/kg of erythromycin lactobionate. Conventional microelectrode techniques were used to record transmembrane action potentials in isolated dog Purkinje fibers and papillary muscles. Erythromycin at concentrations > 20 mg/L prolonged action potential duration. At higher concentrations (100 to 200 mg/L), erythromycin induced phase 2 and phase 3 early afterdepolarizations (EADs) both in vivo and in vitro. The effects of erythromycin on repolarization were more marked in Purkinje fibers than in papillary muscle. Pretreatment of Purkinje fibers with erythromyci...
Linkage analysis and long QT syndrome. Using genetics to study cardiovascular disease.
Authors: MKeating
Journal: Circulation (1992)

BACKGROUNDRecombinant DNA technologies have facilitated the development of a set of polymorphic DNA markers covering the human genome. General linkage analysis in families predisposed to inherited disease is now feasible. Linkage analysis can help identify a disease gene even when relatively little is known about the disorder.METHODS AND RESULTSUsing this approach, we have identified linkage between a gene that causes the long QT syndrome and DNA markers on chromosome 11.CONCLUSIONSThe identification of the chromosomal location of the long QT locus is the first step in defining the specific mutations that cause this disease.
Heat production during hypoxic contracture of rat myocardium.
Authors: CHolubarsch, N RAlpert, RGoulette, L AMulieri
Journal: Circulation Research (1982)

Contracture due to hypoxia, to both oxygen and glucose deficiency, and to potassium chloride was induced in rat left ventricular papillary muscle preparations. Under contracture conditions, the sum of resting heat plus contracture heat was measured using Hill-type, planar vacuum-deposited thermopiles. On the basis of the measured total and initial heat output and the corresponding tension-time integral during single twitches under control conditions (Lmax, 21 degrees C, stimulus frequency 12/min), the expected heat output during contracture was calculated, assuming that the contracture tension is maintained by the same calcium-induced cross-bridge cycling as occurs in the single twitch response. With potassium chloride, the contracture tension was 1.33 +/- 0.27 g/mm2, a value which is similar to those found in hypoxic contracture and in contracture due to both oxygen and glucose deficiency. There was no significant difference between measured and calculated values for resting heat plus contracture heat (8...
Treatment of Glaucoma
Authors: E. G. Recordon
Journal: BMJ (1933)

<h3>Abstract</h3> After the spill to humans, in the timeline of SARS-CoV-2, several positively selected variants have emerged. A phylogeographic study on these variants can reveal their spatial and temporal distribution. In December 2020, the alpha variant of the severe acute respiratory syndrome coronavirus (SARS-CoV-2), which has been designated as a variant of concern (VOC) by WHO, was discovered in the southeastern United Kingdom (UK). Slowly, it expanded across India, with a considerable number of cases, particularly in North India. The study focuses on determining the prevalence and expansion of the alpha variants in various parts of India. The genetic diversity estimation helped us understand various evolutionary forces that have shaped the spatial distribution of this variant during the peak. Overall, our study paves the way to understand the evolution and expansion of a virus variant.
Role of nitric oxide in the regulation of oxygen consumption in conscious dogs.
Authors: WShen, XXu, MOchoa, GZhao, M SWolin, T HHintze
Journal: Circulation Research (1994)

The role of nitric oxide (NO) in the regulation of O2 consumption was studied in chronically instrumented conscious dogs. A specific NO synthesis inhibitor, nitro-L-arginine (NLA, 30 mg/kg i.v.), significantly increased mean arterial pressure from 100 +/- 4 to 134 +/- 5 mm Hg (mean +/- SEM) and total peripheral resistance by 157 +/- 16% and reduced cardiac output by 47 +/- 3% and heart rate by 34 +/- 6% after 120 minutes. Changes in arterial blood gases were not observed. There were significant changes in PO2 (-14 +/- 2 mm Hg), O2 saturation (-21 +/- 2%), the percentage of hemoglobin as oxyhemoglobin (-21 +/- 2%), and O2 content (-3.0 +/- 0.9 vol%) and a significant increase in percent reduced hemoglobin (21 +/- 1%) in mixed venous blood, associated with an increase in O2 extraction (5.1 +/- 0.2 vol%) (all P < .01). O2 consumption was increased from 124 +/- 6 to 155 +/- 9 mL/min (P < .05). Methoxamine, titrated to have hemodynamic effects similar to those of NLA (eg, mean arterial pressure increased from ...
Quantitative relationship between left ventricular function and serum cardiac myosin light chain I levels after coronary reperfusion in patients with acute myocardial infarction.
Authors: MIsobe, RNagai, SUeda, HTsuchimochi, HNakaoka, FTakaku, TYamaguchi, KMachii, MNobuyoshi, YYazaki
Journal: Circulation (1987)

To estimate the extent of myocardial infarction after coronary artery reperfusion, serum levels of cardiac myosin light chain (LC) I and creatine kinase (CK) were determined serially in 49 patients with acute myocardial infarction. Intracoronary thrombolysis was successful in 25 patients (reperfusion group), and 24 patients were treated in a conventional manner (control group). The peak level of CK appeared significantly earlier in the reperfusion group (11.3 +/- 3.1 hr, mean +/- SD) than in the control group (21.6 +/- 7.2 hr). Cumulative release of CK was significantly related to angiographically determined left ventricular ejection fraction 1 month after the attack in both groups (r = -.50; -.45, respectively). However, the amount of cumulative release of CK in the reperfusion group was greater compared with that in those with the same left ventricular ejection fraction in the control group. Peak appearance time of LCI was almost equal in the two groups (3.8 +/- 1.4 vs 3.9 +/- 1.2 days). Peak levels of ...
Endoscopic Interventions for Treatment of Pancreatic Ascites- Six Years Single Center Experience
Authors: P Karagyozov, V Mitova, I Tishkov, I Boeva, I Dobreva
Journal: Endoscopy (2021)

Aims We aimed to retrospectively analyze the data on all patients, admitted in our unit, with clinically significant pancreatic ascites over a six-year period.
Percutaneous excimer laser coronary angioplasty of lesions not ideal for balloon angioplasty.
Authors: S LCook, N LEigler, AShefer, TGoldenberg, J SForrester, FLitvack
Journal: Circulation (1991)

BACKGROUNDExcimer laser coronary angioplasty is a new, investigational technique for treating coronary artery stenoses. Initial reports have demonstrated acute efficacy and relative safety of this procedure, but have not addressed the effect of lesion type on acute success and complication rates.METHODS AND RESULTSIn the first 100 patients undergoing percutaneous excimer laser coronary angioplasty at our institution, acute laser success was obtained in 84% and procedural success was obtained in 94%. There were six acute closures during laser angioplasty and one myocardial infarction. Two patients required emergency coronary bypass surgery. Sixty-five percent of patients had lesions not ideal for balloon angioplasty because of lesion morphology (tubular, diffuse, or chronic total occlusion) or ostial location. There were 10 tubular stenoses, 29 diffuse lesions, 18 chronic total occlusions, and eight ostial lesions, including five aorto-ostial lesions. In this nonideal subgroup, the acute success rate with ...
Linear EUS Accuracy in Gastric Cancer Preoperative Staging: A Retrospective Multicentric Study
Authors: G De Nucci, G Impellizzeri, T Gabbani, P Soriani, S Deiana, L Ottaviani, S Vavassori, J Rainer, GF Bonura, A Curatolo, L Frazzoni, L Fuccio, G Manes, M Vecchi, M Manno
Journal: Endoscopy (2021)

Aims Gastric cancer (GC) staging is the most reliable prognostic factor that affects therapeutic choices. Contrast enhanced computed tomography (CECT) and radial endoscopic ultrasound (R-EUS) are the most used staging tools. The accuracy of linear EUS (L-EUS) in this setting is still controversial.
Noninvasive estimation of the instantaneous first derivative of left ventricular pressure using continuous-wave Doppler echocardiography.
Authors: CChen, LRodriguez, J LGuerrero, SMarshall, R ALevine, A EWeyman, J DThomas
Journal: Circulation (1991)

BACKGROUNDThe complete continuous-wave Doppler mitral regurgitant velocity curve should allow reconstruction of the ventriculoatrial (VA) pressure gradient from mitral valve closure to opening, including left ventricular (LV) isovolumic contraction, ejection, and isovolumic relaxation. Assuming that the left atrial pressure fluctuation is relatively minor in comparison with the corresponding LV pressure changes during systole, the first derivative of the Doppler-derived VA pressure gradient curve (Doppler dP/dt) might be used to estimate the LV dP/dt curve, previously measurable only at catheterization (catheter dP/dt).METHODS AND RESULTSThis hypothesis was examined in an in vivo mitral regurgitant model during 30 hemodynamic stages in eight dogs. Contractility and relaxation were altered by inotropic stimulation and hypothermia. The Doppler mitral regurgitant velocity spectrum was recorded along with simultaneously acquired micromanometer LV and left atrial pressures. The regurgitant velocity profiles we...
Suppression of ventricular ectopic depolarizations by tocainide.
Authors: R LWoosley, D GMcDevitt, A SNies, R FSmith, G RWilkinson, J AOates
Journal: Circulation (1977)

In a previous clinical study we demonstrated that tocainide is effective in the suppression of ventricular ectopic depolarizations (VEDs) after single oral doses. This information provided the basis for evaluating this drug's antiarrhythmic efficacy after multiple dose administration according to a loading-maintenance regimen. Twelve patients with stable VEDs were given loading doses of tocainide (400-600 mg) with maintenance doses every 12 hours. Every 48 hours the dose was increased until either arrhythmia suppression to less than 25% of VED frequency during placebo administration or side effects occurred. Computer analysis of 12-hr telemetric ECGs taken 24-36 hr after each dosage increment documented effective suppression (76-95%) in 8 of 12 patients. Those subjects demonstrating suppression were randomly assigned to a cross-over study of placebo or active drug at the dosage found effective in the dose-ranging phase. Dosages for the cross-over stage ranged from 400 to 1100 mg every 12 hours. Comparison...
Adverse Pregnancy Outcomes and Cardiovascular Disease Risk: Unique Opportunities for Cardiovascular Disease Prevention in Women: A Scientific Statement From the American Heart Association
Authors: Nisha I. Parikh, Juan M. Gonzalez, Cheryl A.M. Anderson, Suzanne E. Judd, Kathryn M. Rexrode, Mark A. Hlatky, Erica P. Gunderson, Jennifer J. Stuart, Dhananjay Vaidya
Journal: Circulation (2021)

This statement summarizes evidence that adverse pregnancy outcomes (APOs) such as hypertensive disorders of pregnancy, preterm delivery, gestational diabetes, small-for-gestational-age delivery, placental abruption, and pregnancy loss increase a woman's risk of developing cardiovascular disease (CVD) risk factors and of developing subsequent CVD (including fatal and nonfatal coronary heart disease, stroke, peripheral vascular disease, and heart failure). This statement highlights the importance of recognizing APOs when CVD risk is evaluated in women, although their value in reclassifying risk may not be established. A history of APOs is a prompt for more vigorous primordial prevention of CVD risk factors and primary prevention of CVD. Adopting a heart-healthy diet and increasing physical activity among women with APOs, starting in the postpartum setting and continuing across the life span, are important lifestyle interventions to decrease CVD risk. Lactation and breastfeeding may lower a woman's later cardiometabolic risk. Black and Asian women experience a higher proportion APOs, with more severe clinical presentation and worse outcomes, than White women. More studies on APOs and CVD in non-White women are needed to better understand and address these health disparities. Future studies of aspirin, statins, and metformin may better inform our recommendations for pharmacotherapy in primary CVD prevention among women who have had an APO. Several opportunities exist for health care systems to improve transitions of care for women with APOs and to implement strategies to reduce their long-term CVD risk. One proposed strategy includes incorporation of the concept of a fourth trimester into clinical recommendations and health care policy.
Abstract 112: Asymmetric Dimethylarginine Predicts Outcome and Time of Stay in Hospital in Patients Attending an Internal Medicine Emergency Room
Authors: Friedrich Schulze, Joern Vollert, Renke Maas, Reinhold Mueller, Christian Mueller, Rainer H Boeger, Martin Moeckel
Journal: Circulation (2007)

Introduction For patients attending the emergency room (ER) valid diagnostic criteria which give information about further progress are needed. We investigated the predictive value of asymmetric di...
Antagonistic modulatory roles of magnesium and calcium on release of endothelium-derived relaxing factor and smooth muscle tone.
Authors: M EGold, G MBuga, K SWood, R EByrns, GChaudhuri, L JIgnarro
Journal: Circulation Research (1990)

The objective of this study was to elucidate the mechanisms associated with the reciprocal relation between magnesium and calcium on vascular smooth muscle tone in bovine pulmonary artery and vein. Rapid removal of magnesium from Krebs-bicarbonate medium used to bathe isolated rings of precontracted artery or vein caused transient endothelium- and calcium-dependent relaxation and cyclic GMP accumulation. Both responses were antagonized by oxyhemoglobin, methylene blue, or superoxide anion and were enhanced by superoxide dismutase. The transient relaxation was followed by sustained endothelium-independent contraction. Endothelium-denuded vascular rings contracted in response to extracellular magnesium depletion without alteration in cyclic GMP levels. The data suggest that vascular endothelium-derived nitric oxide is responsible for the calcium-dependent relaxation elicited by extracellular magnesium depletion. Indeed, in bioassay cascade studies, magnesium removal from the medium used to perfuse intact ar...
17 beta-Estradiol inhibits flow- and acute hypoxia-induced prostacyclin release from perfused endocardial endothelial cells.
Authors: E MRedmond, M NCherian, R CWetzel
Journal: Circulation (1994)

BACKGROUNDBecause of the marked difference in the incidence and severity of cardiovascular diseases between men and premenopausal women, several groups have studied the effect of sex steroids, particularly estrogen, on vascular endothelial prostacyclin (PGI2) release. No previous studies have addressed the effect of estrogen on endocardial endothelial cells (EECs), which are involved in the modulation of the myocardium and potentially in downstream pulmonary and systemic vascular tone. Furthermore, all previous studies of estrogen effects on cultured endothelial cell function have used cells grown under standard static cell culture conditions, thereby ignoring the contribution of flow, the ubiquitous environmental endothelial stimulus.METHODS AND RESULTSThe effect of 17 beta-estradiol pretreatment (100 ng/mL, 72 hours) on cultured sheep EEC PGI2 release in response to multiple physiologically relevant stimuli was studied. EECs were grown in six-well plates (static conditions) or on microcarrier beads and ...
Roles of P2-purinoceptors in the cardiovascular system.
Authors: VRalevic, GBurnstock
Journal: Circulation (1991)

Characterization of P2-purinoceptor subtypes has facilitated understanding of the many diverse effects produced by purine nucleotides. P2X-Purinoceptors are located on vascular smooth muscle where they mediate vasoconstriction resulting from ATP released as a cotransmitter with noradrenaline from sympathetic nerves. P2Y-Purinoceptors are usually located on the vascular endothelium where they have a role as mediators of vascular relaxation by locally produced ATP. In some vessels, P2Y-purinoceptors are also located on the smooth muscle, perhaps in association with purinergic or sensory nerves, where they can elicit direct relaxation to neuronally released ATP. The net effect of ATP and its analogues on isolated vessels or on vascular beds will be the results of actions mediated by P2X- and P2Y-purinoceptor subtypes, although changes in vascular tone and in integrity of nerves and endothelial cells may alter the balance of the response. Such changes have been observed in diseased states (e.g., atheroscleros...
Short-term hemodynamic effects of hydralazine in infants with complete atrioventricular canal defects.
Authors: MArtman, M DParrish, R CBoerth, R JBoucek, T PGraham
Journal: Circulation (1984)

We evaluated the acute hemodynamic responses to hydralazine during cardiac catheterization in eight infants (ages 1.0 to 5.5 months) with congestive heart failure due to complete atrioventricular canal defect. Hydralazine administered intravenously (0.5 to 1.0 mg/kg body weight) increased heart rate and systemic blood flow and decreased mean right atrial pressure, systemic and pulmonic arterial pressures, systemic arteriolar resistance, and the ratio of pulmonary to systemic blood flow (p less than .05). The percentage of pulmonary flow contributed by shunted blood (percent left-to-right shunt; measured by indicator dilution) was decreased by hydralazine in six (mean = 85% before to 64% after hydralazine; p less than .01), but remained unchanged (79%) in two infants. The two infants with no change in percent left-to-right shunt had higher pulmonary arteriolar resistances (Rp) before hydralazine (mean = 12.8 vs 3.2 U/m2) and had greater declines in Rp (mean change = -5.1 vs + 0.3 U/m2) in response to hydra...
Increased Ca2+ signaling after alpha-adrenoceptor activation in vascular hypertrophy.
Authors: PPapageorgiou, K GMorgan
Journal: Circulation Research (1991)

In an effort to explain the increased sensitivity to agonists of hypertrophic vascular muscle, intracellular Ca2+ concentration ([Ca2+]i)-signaling mechanisms were studied in normal and hypertrophic rat aortas from normotensive and coarctation-hypertensive rats. Based on both fura 2 fluorescence and aequorin luminescence measurements, qualitatively different patterns of Ca2+ mobilization occur in normal and hypertrophic rat aortic muscle. Normal rat aortic muscle contracts to phenylephrine with little or no increase in [Ca2+]i, whereas the angiotensin II-induced contraction is accompanied by a marked [Ca2+]i transient. In contrast, hypertrophic rat aortic muscle shows a dramatic increase in Ca2+ signaling after phenylephrine stimulation. Moreover, both the amplitude of the angiotensin-induced [Ca2+]i transient and the contractile sensitivity to this agonist are decreased in the hypertrophic muscle. Our results strongly suggest that the amplitude of the [Ca2+]i transient after agonist stimulation determine...