tbuckley/cabot-search huggingface dataset:
Quantification of jet flow by momentum analysis. An in vitro color Doppler flow study.
Authors: J DThomas, C MLiu, F AFlachskampf, J PO'Shea, RDavidoff, A EWeyman
Journal: Circulation (1990)

Previous investigations have shown that the size of a regurgitant jet as assessed by color Doppler flow mapping is independently affected by the flow rate and velocity (or driving pressure) of the jet. Fluid dynamics theory predicts that jet momentum (given by the orifice flow rate multiplied by velocity) should best predict the appearance of the jet in the receiving chamber and also that this momentum should remain constant throughout the jet. To test this hypothesis, we measured jet area versus driving pressure, flow rate, velocity, orifice area, and momentum and showed that momentum is the optimal jet parameter: jet area = 1.25 (momentum).28, r = 0.989, p less than 0.0001. However, the very curvilinear nature of this function indicated that chamber constraint strongly affected jet area, which limited the ability to predict jet momentum from observed jet area. To circumvent this limitation, we analyzed the velocities per se within the Doppler flow map. For jets formed by 1-81-mm Hg driving pressure thro...
Acute respiratory acidosis decreases left ventricular contractility but increases cardiac output in dogs.
Authors: K RWalley, T HLewis, L DWood
Journal: Circulation Research (1990)

To understand the cardiovascular response to respiratory acidosis, we measured hemodynamics, left ventricular pressure, and left ventricular volume (three ultrasonic crystal pairs) during eucapnia and respiratory acidosis in 10 fentanyl-anesthetized open-chest dogs. Left ventricular contractility was assessed primarily by measuring the slope (Emax) and intercept (V0) of the left ventricular end-systolic pressure-volume relation determined by combining end-systolic points from a vena caval occlusion and from brief aortic cross-clamping. Respiratory acidosis (pH 7.09, Pco2 92 mm Hg) reduced contractility by a decrease in Emax (11.4 to 9.2 mm Hg/ml, p less than 0.01) with no change in V0. Despite this, cardiac output increased (1.7 to 2.1 l/min, p less than 0.01), and heart rate increased (96 to 121 beats/min, p less than 0.05), with no change in blood pressure. Systemic vascular resistance fell by 26% (p less than 0.01). During eucapnia, propranolol reduced Emax (11.4 to 4.6 mm Hg/ml, p less than 0.01) with...
Stability of heterogeneity of myocardial blood flow in normal awake baboons.
Authors: R BKing, J BBassingthwaighte, J RHales, L BRowell
Journal: Circulation Research (1985)

Regional myocardial blood flow has been thought to be relatively uniform, in accord with the singular function of myocardial cells. However, considerable spatial heterogeneity has been observed in the hearts of anesthetized animals and in isolated hearts. Studies were undertaken in a total of 13 baboons. Eleven were awake, healthy animals sitting in chairs at rest or feeding, some performed mild leg exercise (wheel turning), and others were subjected to whole body heating; two were anesthetized, methodological controls. Microspheres (15 +/- 3 micron diameter, 0.5 X 10(6)/kg body weight) were injected via a catheter into the apex of the left ventricle while arterial blood was sampled at a constant rate for calculating cardiac output. Microspheres with different labels were injected at six intervals of 20 minutes to several hours. On sacrifice, the hearts were sectioned into 204 locatable pieces (left ventricle, 168; right ventricle, 27; and atria, 9). Average resting myocardial flow was 2.1 +/- 0.2 ml/g pe...
RE: BRCA2 Polymorphic Stop Codon K3326X and the Risk of Breast, Prostate, and Ovarian Cancers
Authors: Eloisa Arbustini, Adele Sgarella, Alberta Ferrari, Donatella Grasso, Chiara Cassani, Marco Lucioni, Giuseppe Di Giulio, Maurizia Grasso
Journal: JNCI Journal of the National Cancer Institute (2016)
Comparison of Ca2+, Sr2+, and Mn2+ fluxes in mitochondria of the perfused rat heart.
Authors: D RHunter, HKomai, R AHaworth, M DJackson, H ABerkoff
Journal: Circulation Research (1980)

The amount of readily exchangeable Ca2+ in mitochondria of an isolated working rat heart is less than 10 ng-ions/g heart. We therefore conclude that either no Ca2+ enters mitochondria or that the Ca+ which does enter is removed continuously. Using Sr2+ and Mn2+, we obtained evidence that the mitochondrial Na+-Ca2+ exchanger was indeed operational in releasing metal from mitochondria of the heart. When Ca2+ in the perfusate was replaced by Sr2+, we found that a significant amount of Sr2+ (approximately 100 ng-ions/g heart) entered mitochondria. When the heart then was returned to a Ca2+-containing perfusate, over 80% of the Sr2+ was washed out of mitochondria within 30 seconds. When low levels of Mn2+ were added to the perfusate, we found that Mn2+ accumulated in mitochondria irreversibly. This is evidence for the operation of the Na+-Ca2+ exchanger because Na+ was found to release Ca2+ and Sr2+ but not Mn2+ from isolated rat heart mitochondria. Our estimates indicate that when the Na+-Ca2+ exchanger is ma...
Complement and neutrophil activation in the pathogenesis of ischemic myocardial injury.
Authors: M HCrawford, F LGrover, W PKolb, C AMcMahan, R AO'Rourke, L MMcManus, R NPinckard
Journal: Circulation (1988)

Complement depletion with cobra venom factor (CVF) before coronary artery ligation has been previously shown to reduce subsequent ischemic myocardial tissue injury in the baboon; however, whether complement depletion after the initiation of acute myocardial ischemia affords similar myocardial preservation is not known. Both complement depletion with CVF or the administration of certain nonsteroidal anti-inflammatory drugs, including ibuprofen, are thought to decrease myocardial infarct size by reducing polymorphonuclear leukocytic (PMN) infiltration; nevertheless, complement activation also could alter tissue injury by PMN-independent actions. Thus, the relative effects of CVF administered after coronary artery ligation on the subsequent development of myocardial tissue injury were assessed in a baboon myocardial infarction model. The animals were randomized into three treatment groups (n = 6): either CVF (125 units/kg) or saline was given 30 minutes after coronary artery ligation, and ibuprofen (12.5 mg/...
Introduction of vascular smooth muscle cells expressing recombinant genes in vivo.
Authors: GPlautz, E GNabel, G JNabel
Journal: Circulation (1991)

Vascular smooth muscle cells contribute to the formation of atherosclerotic plaques by proliferating in response to vascular injury and releasing growth-promoting factors. Because their autocrine and paracrine effects are not fully understood, expression of such growth factor genes in specific cell types in vivo would help to determine their mechanism of action. We describe a method to transfer vascular smooth muscle cells expressing recombinant gene products to localized segments of the arterial wall. Vascular smooth muscle cells from the inbred Yucatan minipig were infected in vitro with an amphotropic, replication-defective retrovirus transducing the gene for Escherichia coli beta-galactosidase. Vascular smooth muscle cells expressing this recombinant gene were implanted, using a catheter, into denuded iliofemoral artery segments of pigs in vivo. These arteries subsequently demonstrated beta-galactosidase activity in cells of the intima and media. This method, which provides for the introduction of gen...
Voltage clamp analysis of the effects of dopamine on the transmembrane ionic currents underlying the action potential of sheep cardiac Purkinje fibers.
Authors: J MGelles, R SAronson
Journal: Circulation Research (1977)

Dopamine shifted the voltage-dependence of the slow outward current that underlies spontaneous diastolic depolarization to a more positive voltage range and increased the rate constants of inactivation of this current at voltages negative to -80 mV. Dopamine increased the magnitude of the slow inward current and the delayed outward current. Dopamine had an inconsistent effect on the positive dynamic current and the time-independent potassium current. These effects were consistent with effects on the slope of diastolic depolarization, plateau voltage, and action potential duration and are similar to those of epinephrine. The effects of dopamine on the slow inward current and on the delayed outward current were abolished by verapamil, a slow channel blocker. This finding substantiates that outward potassium currents are modulated by intracellular calcium.
Mildly dilated congestive cardiomyopathy. Use of prospective diagnostic criteria and description of the clinical course without heart transplantation.
Authors: AKeren, SGottlieb, DTzivoni, SStern, RYarom, M EBillingham, R LPopp
Journal: Circulation (1990)

Prognosis in classically described dilated congestive cardiomyopathy has been reported to be related to ventricular size. Mildly dilated congestive cardiomyopathy (MDCM) has been defined as end-stage heart failure of unknown etiology (New York Heart Association class IV, left ventricular ejection fraction less than 30%), occurring with neither typical hemodynamic signs of restrictive myopathy nor significant ventricular dilatation (less than 15% above normal range). The present study includes follow-up in 12 nontransplant patients. In the first 4 months after diagnosis, two patients improved and are living, and two showed cardiac dilation and clinical deterioration and died. Six of the remaining eight with persistent MDCM died (four with intractable heart failure and two, sudden deaths) without change in ventricular size before death, despite medical therapy over 20 +/- 8 months. Eight comparable transplanted patients with persistent MDCM demonstrated improved total survival by life table analysis (p less...
Subcellular mechanism for Ca(2+)-dependent enhancement of delayed rectifier K+ current in isolated membrane patches of guinea pig ventricular myocytes.
Authors: JNitta, TFurukawa, FMarumo, TSawanobori, MHiraoka
Journal: Circulation Research (1994)

Intracellular Ca2+ augments delayed rectifier K+ current (IK) in cardiac myocytes, which may play a major modulatory role in repolarization of action potentials. We investigated subcellular mechanisms for Ca(2+)-induced enhancement of IK in large-pipette inside-out membrane patches excised from isolated guinea pig ventricular myocytes. When [Ca2+]i was raised from 10(-8) to 10(-6) mol/L, the amplitude of IK measured at +80 mV was increased from 12.0 +/- 2.2 to 19.5 +/- 3.3 pA (P < .01). The enhancement of IK by Ca2+ was dose dependent, with an EC50 of 3.8 x 10(-8) mol/L. A calmodulin antagonist, W7 (50 mumol/L), calmidazolium (100 mumol/L), or HT-74 (20 mumol/L), added to the intracellular solution abolished enhancement of IK by Ca2+, whereas the inactive form of the W7 analogue, W5, had no effect on IK. In the presence of a protein kinase inhibitor with a relatively high specificity for protein kinase C (H7), for protein kinase A (H8 or peptide-type inhibitor PKI), or for calmodulin kinase II (KN-62) or ...
Developmental changes in the electrophysiological properties and the beta-adrenergic receptor-effector complex in atrial fibers of the canine coronary sinus.
Authors: E MHorn, N JJohnson, J PBilezikian, M RRosen
Journal: Circulation Research (1989)

beta-Adrenergic stimulation induced delayed afterdepolarizations and triggered activity in atrial fibers of adult but not young canine coronary sinus. However, sensitivity to beta-adrenergic agonists with respect to maximum diastolic potential was identical at both ages, and delayed afterdepolarizations and triggered activity did occur in response to ouabain. Age-dependent lengthening of the action potential duration and plateau also were seen and were greater in the adult than the young. beta-Adrenergic receptor density and affinity and the stimulatory guanine nucleotide regulatory protein (Gs) were similar in adult and young tissues. In contrast, the inhibitory guanine nucleotide regulatory protein (Gi) was 2.5-fold greater in adult (15 fmol/mg) than in young (6.0 fmol/mg) tissues. Basal- and forskolin-stimulated adenylate cyclase activities were greater in adult than young coronary sinus although the increment in isoproterenol-stimulated adenylate cyclase activity in young tissue was greater when compa...
A Systematic Review and Meta-Analysis on Endoscopists’ Accuracy for Detecting Upper Gastrointestinal Neoplasia in Artificial Intelligence Studies: What is the Gold-Standard?
Authors: L Frazzoni, J Arribas, G Antonelli, C Hassan, L Fuccio, M Dinis-Ribeiro
Journal: Endoscopy (2021)

Aims Estimates on miss rates for upper gastrointestinal neoplasia (UGIN), i.e. approximately 10 % mainly relies on registry data or old studies. Significant technological breakthroughs and quality parameters have been issued thereafter. We aimed at assessing endoscopists’ accuracy for detecting UGIN within artificial intelligence (AI) studies.
Antiarrhythmic actions of the ATP-regulated K+ current activated by pinacidil.
Authors: WSpinelli, SSorota, MSiegal, B FHoffman
Journal: Circulation Research (1991)

We tested the hypothesis that a selective increase in membrane current, as contrasted with the decreases in currents caused by most antiarrhythmic agents, would be an effective antiarrhythmic intervention. We studied models of early afterdepolarizations (EADs), delayed afterdepolarizations (DADs), and abnormal automaticity in single canine ventricular myocytes using intracellular microelectrodes or patch electrodes. EADs were induced by injected current, Bay K 8644 (0.5-1 microM), or ketanserin (1.0 microM); DADs were induced by ouabain intoxication (2 x 10(-7) M); and abnormal automaticity was induced by exposure to barium (0.25 mM). To increase outward K+ current, we used pinacidil and the protein kinase C activator 4 beta-phorbol 12,13-dibutyrate (PDBu). Under control conditions, 10-100 microM pinacidil caused a concentration-dependent and reversible decrease in action potential duration and an increase in steady-state outward current; both effects were blocked by glibenclamide and thus presumably refl...
Efficacy of propranolol in the control of exercise-induced or augmented ventricular ectopic activity.
Authors: J VNixon, WPennington, WRitter, WShapiro
Journal: Circulation (1978)

The effect of propranolol on exercise-induced or augmented ventricular ectopy was studied in sixteen male patients, six of whom had documented coronary artery disease. Fifteen patients were exercised after two weeks of oral therapy, fourteen after single oral therapy and eight patients after intravenous therapy. Propranolol dosage was titrated to produce maximal beta-adrenergic blockade. Effective reduction of exercise-induced ventricular ectopy occurred in ten of fifteen patients (P less than 0.001), and in five of six patients with coronary disease (P less than 0.02). Propranolol therapy abolished ventricular couplets in eight of twelve patients and ventricular tachycardia in four of the patients. Single oral and intravenous therapy had similar or greater effects. Plasma propranolol levels following different routes of administration did not correlate with exercise-induced maximal heart rates or percent reduction in ventricular ectopy. When compared to exercise in eleven patients, ambulatory monitoring ...
Improvement of resting myocardial asynergy with cessation of upright bicycle exercise.
Authors: ARozanski, UElkayam, D SBerman, G ADiamond, JPrause, H JSwan
Journal: Circulation (1983)

Exercise generally aggravates ischemic myocardial dysfunction, presumably by increasing tissue oxygen demand out of proportion to the increase in supply. Nevertheless, resting left ventricular (LV) wall motion abnormalities can improve dramatically after upright exercise. To investigate this paradoxical phenomenon, we performed upright bicycle exercise equilibrium radionuclide ventriculography in 93 patients with angiographic coronary artery disease. Immediately after exercise, LV end-diastolic volume was similar to the resting level (1 +/- 22% of rest value), but end-systolic volume (ESV) was significantly below (p less than 0.05) that at rest (-11 +/- 32%) and LV ejection fraction increased significantly compared with rest (0.57 +/- 0.16 vs 0.51 +/- 0.13, p less than 0.05). Improvement in resting myocardial asynergy was frequent (115 of 330 abnormal segments), and was observed more commonly in patients without pathologic Q waves and in segments manifesting mild rather than severe asynergy. In 60 addit...
Characteristics of the resuscitated out-of-hospital cardiac arrest victim with coronary heart disease.
Authors: SGoldstein, J RLandis, RLeighton, GRitter, C MVasu, ALantis, RSerokman
Journal: Circulation (1981)

The clinical entry characteristics and medical history of 142 resuscitated out-of-hospital cardiac arrest victims with coronary heart disease were studied in order to identify factors that affect their long-term survival. The cardiac arrest event was classified as being secondary to an acute myocardial infarction (AMI) in 44% (62 of 142), an ischemic event (IE) in 34% (49 of 142) and a primary arrhythmic event (PAE) in 22% (31 of 142). The majority of patients in all groups had a history of angina pectoris. Twenty-seven percent of the AMI, 55% of the IE, and 71% of the PAE patients had a history of infarction. Ten percent of the AMI, 31% of the IE, and 55% of the PAE had used digitalis before their cardiac arrest. Cardiac arrest was the first cardiac event in 35% of the AMI, 16% of the IE and 6% of the PAE patients. One year after arrest, 89% of the AMI, 80% of the IE and 71% of the PAE were alive (p less than 0.01). Covariate analysis for more than 40 variables indicates that a high-risk group included 2...
Glomerular and vascular atrial natriuretic factor receptors in saralasin-sensitive and -resistant two-kidney, one-clip hypertensive rats.
Authors: RGarcia, GGauquelin, MCantin, E LSchiffrin
Journal: Circulation Research (1988)

We have investigated whether there is a relation between renin dependency of two-kidney, one-clip (2K1C) hypertensive rats and the density of renal glomerular and vascular atrial natriuretic factor (ANF) receptors. Conscious 2K1C rats with blood pressure of 150 mm Hg or higher were classified according to their sensitivity to the blood pressure-lowering effect of the angiotensin II antagonist saralasin. Both hypertension groups had lower body weights and greater relative heart weights than normotensive controls. Hematocrit was lower and plasma volume higher in saralasin-resistant animals than in either saralasin-sensitive or control rats. Plasma renin activity was higher in the saralasin-sensitive group than in the resistant rats. Plasma ANF concentration was greater in saralasin-resistant than in either normotensive or saralasin-sensitive animals. ANF was reduced in both atria of saralasin-resistant 2K1C animals but only in the left atrium of the sensitive group. Both hypertensive groups showed an increa...
COVID-19 Incidence and Mortality Among American Indian/Alaska Native and White Persons — Montana, March 13–November 30, 2020
Authors: Laura L. Williamson, Todd S. Harwell, Todd M. Koch, Stacey L. Anderson, Magdalena K. Scott, James S. Murphy, Greg S. Holzman, Helen F Tesfai
Journal: MMWR Morbidity and Mortality Weekly Report (2021)

Geographic differences in infectious disease mortality rates have been observed among American Indian or Alaska Native (AI/AN) persons in the United States (1), and aggregate analyses of data from selected U.S. states indicate that COVID-19 incidence and mortality are higher among AI/AN persons than they are among White persons (2,3). State-level data could be used to identify disparities and guide local efforts to reduce COVID-19-associated incidence and mortality; however, such data are limited. Reports of laboratory-confirmed COVID-19 cases and COVID-19-associated deaths reported to the Montana Department of Public Health and Human Services (MDPHHS) were analyzed to describe COVID-19 incidence, mortality, and case-fatality rates among AI/AN persons compared with those among White persons. During March-November 2020 in Montana, the estimated cumulative COVID-19 incidence among AI/AN persons (9,064 cases per 100,000) was 2.2 times that among White persons (4,033 cases per 100,000).* During the same period, the cumulative COVID-19 mortality rate among AI/AN persons (267 deaths per 100,000) was 3.8 times that among White persons (71 deaths per 100,000). The AI/AN COVID-19 case-fatality rate (29.4 deaths per 1,000 COVID-19 cases) was 1.7 times the rate in White persons (17.0 deaths per 1,000). State-level surveillance findings can help in developing state and tribal COVID-19 vaccine allocation strategies and assist in local implementation of culturally appropriate public health measures that might help reduce COVID-19 incidence and mortality in AI/AN communities.
Characterization of A1 adenosine receptors in atrial and ventricular myocardium from diseased human hearts.
Authors: MBöhm, BPieske, MUngerer, EErdmann
Journal: Circulation Research (1989)

The purpose of the present study was to characterize adenosine receptors in human atrial and ventricular myocardium. In isolated electrically driven preparations, adenosine produced direct negative inotropic effects in atrial myocardium (AT). In ventricular myocardium (VE), it only had negative inotropic properties when force of contraction had been stimulated with isoprenaline (indirect effect), but it has no inotropic effect alone. The adenosine receptor antagonist 8-phenyltheophylline antagonized the direct and indirect effects; these findings indicated that both effects were mediated by adenosine receptors. In cardiac membranes from human AT and VE, adenosine receptors were characterized with [3H]-8-cyclopentyl-1,3-dipropylxanthine (DPCPX) binding. The effects of agonists R-(-)-N6-phenylisopropyladenosine (R-PIA), S-(+)-N6-phenylisopropyladenosine (S-PIA), and 5'-(N-ethylcarboxamido) adenosine (NECA) and the effects of guanine nucleotides [Gpp(NH)p] were studied also. The antagonist affinities...
Asthma attacks seen in primary care halved in England during pandemic, study finds
Authors: Shaun Griffin
Journal: BMJ (2021)

Asthma attacks seen in primary care halved in England during pandemic, study finds Shaun GriffinGPs in England saw patient consultations for asthma exacerbations halve during the UK's first lockdown, a study has found, 1 although the number of people needing hospital treatment remained the same.1
Carotid Endarterectomy and Statin Therapy in the Management of Patients With Carotid Artery Disease
Authors: John R. Kapoor
Journal: JAMA (2008)

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