tbuckley/cabot-search huggingface dataset:
Forearm vascular responsiveness to alpha 1- and alpha 2-adrenoceptor stimulation in patients with congestive heart failure.
Authors: CIndolfi, AMaione, MVolpe, ARapacciuolo, GEsposito, RCeravolo, VRendina, MCondorelli, MChiariello
Journal: Circulation (1994)

BACKGROUNDThe alpha-adrenergic component of the sympathetic nervous system plays a major role in the pathophysiology, clinical manifestations, and natural history of human congestive heart failure (CHF). However, the functional integrity of vascular alpha 1- and alpha 2-adrenoceptors in CHF remains to be elucidated. The present study was designed to assess the vascular responsiveness of alpha 1- and alpha 2-adrenoceptors in patients with CHF.METHODS AND RESULTSTo evaluate alpha 1- and alpha 2-adrenoceptor responsiveness, we studied the effects of the regional infusion into the brachial artery of increasing doses of phenylephrine (a selective alpha 1-adrenoceptor agonist) and BHT 933 (a selective alpha 2-adrenoceptor agonist) on vascular responses in 12 healthy subjects and in 24 patients with CHF secondary to primary dilated cardiomyopathy or ischemic heart disease. Left ventricular ejection fraction was measured by radionuclide angiography, and forearm blood flow was determined by venous occlusion plethy...
Suppression of endothelin-1 secretion by lysophosphatidylcholine in oxidized low density lipoprotein in cultured vascular endothelial cells.
Authors: MJougasaki, KKugiyama, YSaito, KNakao, HImura, HYasue
Journal: Circulation Research (1992)

Oxidatively modified low density lipoprotein (oxidized LDL), an atherogenic lipoprotein that exists in the atherosclerotic arteries, has been shown to alter endothelial cell functions. In the present study, we examined the effects of oxidized LDL on the production of endothelin-1-like immunoreactivity (ET-1-LI) by the cultured vascular endothelial cells from porcine aorta and human umbilical vein. Incubation with oxidized LDL resulted in a dose-dependent suppression of ET-1-LI release by both endothelial cells. Oxidized LDL also inhibited thrombin-mediated stimulation of ET-1-LI secretion. However, native LDL had no effects on ET-1-LI secretion. A lipid extract from oxidized LDL, but not from native LDL, inhibited ET-1-LI secretion, indicating that the lipid component of oxidized LDL was required for the inhibition of ET-1-LI secretion. Oxidative modification of LDL was associated with degradation of a substantial amount of phosphatidylcholine to lysophosphatidylcholine (LPC). Pretreatment with defatted a...
Transcatheter umbrella closure of congenital heart defects.
Authors: J ELock, J TCockerham, J FKeane, J PFinley, P EWakely, K EFellows
Journal: Circulation (1987)

Between October 1984 and September 1986, we attempted transcatheter umbrella closure, using the Rashkind PDA occluder, of 12 congenital or postoperative cardiovascular  (other than patent ductus arteriosus [PDA]) in 11 patients. In each, we used the umbrella for closure because the defect was too short and/or too large to close with conventional transcatheter methods. The  included three post-Glenn venous communications (superior vena cava-right atrium, n = 2; azygos vein to inferior vena cava), four congenital interatrial defects producing cyanosis (coronary sinus septal defect, left superior vena cava to left atrium, patent foramen ovale, left inferior vena cava to left atrium), and five non-PDA systemic-to-pulmonary arterial communications (two congenital and three postoperative). Ten of 12  were embolized successfully; nine had complete or subtotal closure, and one was partially closed. The first attempted closure resulted in embolization of a 12 mm device to a lower-lobe pulm...
Electrical stimulation of the endothelial surface of pressurized cat middle cerebral artery results in TTX-sensitive vasoconstriction.
Authors: D RHarder, J AMadden
Journal: Circulation Research (1987)

The purpose of this study was to examine the electrical and mechanical responses of cat middle cerebral arteries to electrical stimulation of the adventitial vs. intimal surface of the vessels and to determine the responses as a function of transmural pressure. Middle cerebral arteries were cannulated at both ends. Within each cannula was a stimulating electrode. Electrical stimulation (0.5-msec square current pulses at 0.5 Hz yielding 160 microA of current between electrodes) resulted in significant reduction in diameter that was greater at both 40 and 80 mm Hg vs. 100 or 140 mm Hg. Conversely, adventitial stimulation of perivascular nerves with transmural platinum stimulating electrodes resulted in significant vasodilation. The constrictor response to intimal stimulation, as well as the dilatory response to adventitial stimulation, was blocked by tetrodotoxin. The constrictor response to luminal stimulation was enhanced by scorpion toxin demonstrating a functional role for tissues containing fast Na+ ch...
From the authors
Authors: M. Hoogendoorn, M. P. M. H. Rutten-van Mölken, T. L. Feenstra
Journal: European Respiratory Journal (2005)

We would like to thank N.B.Pride for the interest in our article [1] and the opportunity to elaborate on our projections of the increasing prevalence of chronic obstructive pulmonary disease (COPD) in the Dutch population.
Effect of temperature on digital systolic pressures in lower limb in arterial disease.
Authors: A MSawka, S ACarter
Journal: Circulation (1992)

BACKGROUNDToe pressures correlate with the chances of healing of skin lesions and with the risk of amputation and mortality. They are not affected by incompressibility of the tibial vessels, which may render ankle pressures inaccurate and reflect the overall arterial obstruction down to the digits. Digital pressures, however, may be affected by temperature.METHODS AND RESULTSMeasurements under routine laboratory conditions were compared with those at controlled temperatures in 77 limbs with arteriosclerosis obliterans. The desired local temperatures were attained by perfusing water through the cuffs for 7 minutes before the measurements while the flow was interrupted by a tourniquet to allow equilibration of the toe and water temperatures. Mean toe pressure of 34 +/- 4 mm Hg at 10 degrees C was significantly lower (p less than 0.001) than the values during routine measurements (57 +/- 4 mm Hg) and at 30 degrees C (69 +/- 4 mm Hg). The pressure at 30 degrees C was 10 +/- 3 mm Hg higher than during routine ...
Echocardiographic assessment of a normal adult aging population.
Authors: GGerstenblith, JFrederiksen, F CYin, N JFortuin, E GLakatta, M LWeisfeldt
Journal: Circulation (1977)

Echocardiograms were performed on 105 male participants in the National Institutes on Aging's volunteer Longitudinal Study Program. All subjects (25--84 years of age) were physically active and had no evidence of hypertension or cardiovascular disease. Measurements were made of the initial diastolic (E-F) slope of the anterior mitral valve leaflet, the aortic and left ventricular cavity dimensions, and the thickness of the posterior left ventricular wall. Fractional shortening of the minor semi-axis of the left ventricle and the velocity of circumferential fiber shortening were also determined. It was found that increasing age correlated with a decrease mitral valve E-F slope and increased aortic root diameter and left ventricular wall thickness. Aging did not affect left ventricular cavity dimension, fractional shortening of the minor semi-axis, and velocity of circumferential fiber shortening. These findings suggest that aging in the normal male is associated with altered left ventricular diastolic fill...
The prevalence and clinical significance of residual myocardial ischemia 2 weeks after uncomplicated non-Q wave infarction: a prospective natural history study.
Authors: R SGibson, G ABeller, MGheorghiade, T WNygaard, D DWatson, B LHuey, S LSayre, D LKaiser
Journal: Circulation (1986)

Despite having smaller infarct size and better left ventricular function, patients with non-Q wave myocardial infarction (NQMI) appear to have an unexpectedly high long-term mortality that is ultimately comparable to that of patients with Q-wave myocardial infarction (QMI). Patients with NQMI may lose their initial prognostic advantage because there is more viable tissue in the perfusion zone of the infarct-related vessel, rendering myocardium more prone to reinfarction. We tested this hypothesis in a prospective study of 241 consecutive patients 65 years of age or younger with acute uncomplicated myocardial infarction confirmed by creatine kinase levels (MB fraction). All patients received customary care and none underwent thrombolytic therapy or emergency angioplasty. Predischarge coronary angiography, radionuclide ventriculography, 24 hr Holter monitoring, and quantitative thallium-201 (201T1) scintigraphy during treadmill exercise were performed 10 +/- 3 days after infarction. Infarcts were designated...
Natriuretic activity of human and monkey atria.
Authors: M NNemeh, J PGilmore
Journal: Circulation Research (1983)

Recent evidence indicates that mammalian atria contain a substance that produces a rapid onset natriuresis in anesthetized rats. In the present experiments, small portions of human right atria obtained from patients undergoing coronary bypass surgery, as well as monkey atria and ventricles obtained from the Regional Primate Center, Seattle, were boiled or acid extracted and lyophilized. These materials (30 mg/kg) were dissolved in Ringer's lactate and injected intravenously into anesthetized monkeys to determine their effects on renal function. Their effects were also compared with those of furosemide (0.1 mg/kg) and chlorothiazide (10 mg/kg). Human and monkey atrial extracts produced significant increases in sodium and calcium excretion that were independent of changes in creatinine clearance. Monkey ventricular extract had no consistent renal effects. Furosemide, but not chlorothiazide, mimicked the renal responses to human and monkey atrial extracts in terms of time of onset, duration, and pattern of e...
Intravascular ultrasound cross-sectional arterial imaging before and after balloon angioplasty in vitro.
Authors: J MTobis, J AMallery, JGessert, JGriffith, DMahon, MBessen, MMoriuchi, LMcLeay, MMcRae, W LHenry
Journal: Circulation (1989)

A prototype ultrasound imaging catheter was evaluated in vitro using 17 human atherosclerotic artery segments before and after balloon dilatation angioplasty. The catheter was 1.2 mm in diameter and incorporated a single 20-MHz ultrasound transducer to obtain cross-sectional images of the arterial lumen. In 15 of the 17 (88%) arteries, high quality images were obtained, which demonstrated clear demarcation between the lumen and the endothelium, the atheroma plaque, the muscular media, and the adventitia. Qualitative characteristics of plaque disruption, dissection, and residual flaps were readily visible. In addition, quantitative information about cross-sectional lumen area was obtained before and after balloon dilatation. The mean cross-sectional lumen area increased from 8.7 to 15.1 mm2 (p less than 0.01) following balloon dilatation. The lumen area measured from the ultrasound images following dilatation correlated closely with the area measured from histologic sections (r = 0.88). The results from th...
The role of arterial baroreceptors in the regulation of arterial pressure in conscious dogs.
Authors: R JMcRitchie, S FVatner, G RHeyndrickx, EBraunwald
Journal: Circulation Research (1976)

To elucidate the role of arterial baroreceptors in the acute regulation of arterial pressure in the conscious animal, arterial pressure was lowered and raised in intact, conscious dogs, and in dogs after bilateral section of both carotid sinus and aortic nerves (total arterial baroreceptor denervation, TABD). Pressure was altered by intravenous bolus injections and continuous infusions of nitroglycerin and methoxamine and also by hemorrhage. TABD resulted in a change in peak mean arterial pressure 2-4 times as great as that seen in intact dogs following injection of nitroglycerin or methoxamine. However, when the time taken for the arterial pressure disturbance to return to control levels, as well as the absolute change in arterial pressure, was considered (the pressure-time product), responses of dogs with TABD were far greater for nitroglycerin (7-9 times that seen in intact dogs) and methoxamine (11-15 times). Arterial pressure responses of dogs with selective section of the carotid sinus nerves were i...
Detection of left main coronary artery stenosis by transesophageal color Doppler and two-dimensional echocardiography.
Authors: KYoshida, JYoshikawa, THozumi, YYamaura, TAkasaka, TFukaya, HKato
Journal: Circulation (1990)

Although transthoracic two-dimensional echocardiography can detect dilation of the coronary arteries, the reliability of this technique in the detection of coronary artery stenosis is still doubtful. The purpose of this study was to test the ability of newly developed biplane transesophageal color Doppler and two-dimensional echocardiography in the detection of left main coronary artery stenosis. Blood flow in the left main coronary artery was detected in 57 of 67 (85%) patients by transesophageal color Doppler flow imaging. Using transesophageal two-dimensional echocardiography, adequate images of the full length of the left main coronary artery and identification of the bifurcation were obtained in 60 of 67 (90%) patients. Transesophageal echocardiography clearly showed significant (greater than or equal to 50%) narrowing of the coronary lumen in 10 of 11 patients (sensitivity, 91%) and insignificant narrowing or no abnormalities of the coronary lumen in the other 49 patients (specificity, 100%). The po...
Active modulation of electrical coupling between cardiac cells of the dog. A mechanism for transient and steady state variations in conduction velocity.
Authors: M SSpach, J MKootsey, J DSloan
Journal: Circulation Research (1982)

Propagation velocities of action potentials were measured simultaneously along the longitudinal and transverse axes of cardiac fibers in ventricular muscle. The anisotropic distribution of propagation velocities was found to be altered transiently and in the steady state by the rate and pattern of stimulation and by ouabain. The relative amount of velocity change varied with the direction of propagation and was greatest in the direction perpendicular to the long fiber axis. None of the variables usually associated with the membrane ionic mechanism of depolarization--resting potential, Vmax, and taufoot--showed enough variation to account for the observed changes in velocity. A simplified anisotropic propagation model representing the internal current pathway as an alternating sequence of cytoplasmic and junctional resistance is presented, taking into account the larger contribution to the internal resistance made by the cell couplings in the transverse direction than in the longitudinal direction. On the ...
Acceleration of idioventricular rhythms by histamine in guinea pig heart: mediation by H2 receptors.
Authors: RLevi, J HZavecz
Journal: Circulation Research (1979)

To evaluate the ability of histamine to induce ventricular arrhythmias, we studied the effects of histamine on ventricular rhythmicity in the isolated guinea pig heart with complete atrioventricular conduction block. As a function of dose (0.1-30 microgram), histamine enhanced the idioventricular rate by increasing the rate of firing of the original pacemaker and also by causing the sudden appearance of faster idioventricular rhythms that coincided with changes in pacemaker site. Anaphylaxis in the isolated guinea pig heart with complete atrioventricular conduction block caused histamine release and acceleration of idioventricular rate. The effects of histamine on idioventricular rhythmicity were not attenuated by the histamine H1 receptor antagonist chlorpheniramine, but were antagonized by the H2 receptor antagonist cimetidine. Moreover, the selective H2 agonist 4-methylhistamine (4MeH) accelerated the idioventricular rate, whereas 2-(2-thiazolyl) ethylamine (ThEA), at doses selective for H1 receptor ac...
Physician-Assisted Suicide
Authors: Faye Girsh
Journal: Annals of Internal Medicine (2002)

Letters6 August 2002Physician-Assisted SuicideFaye Girsh, EdDFaye Girsh, EdDThe Hemlock Society; Denver, CO 80250-1810Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-137-3-200208060-00018 SectionsAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail TO THE EDITOR:The position adopted by the College opposing the legalization of physician-assisted dying (1) is typical of the attitudes of physicians that drive away patients and make them gratefully seek a source like Jack Kevorkian for the ultimate relief of their suffering. This position forces physicians to turn away from desperate patients or to break the law to provide compassionate help at their peril. It forces people to live longer than they would ever want to, it puts their families through anguish, and it often leads the sufferer or the loved one to a weapon or to some ...Reference1. Snyder L, Sulmasy DP. Physician-assisted suicide. Ann Intern Med. 2001;135:209-16. [PMID: 11487490] LinkGoogle Scholar Author, Article, and Disclosure InformationAuthors: Faye Girsh, EdDAffiliations: The Hemlock Society; Denver, CO 80250-1810 PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetailsSee AlsoPhysician-Assisted Suicide Lois Snyder , Daniel P. Sulmasy , and Physician-Assisted Suicide Lois Snyder , Daniel P. Sulmasy , and William E. Golden Physician-Assisted Suicide Cavin P. Leeman Physician-Assisted Suicide Antoine de Torrenté Metrics 6 August 2002Volume 137, Issue 3Page: 216KeywordsFearSuicide ePublished: 6 August 2002 Issue Published: 6 August 2002 Copyright & PermissionsCopyright © 2002 by American College of Physicians. All Rights Reserved.PDF downloadLoading ...
Adenosine metabolism in canine myocardial reactive hyperemia.
Authors: R AOlsson, J ASnow, M KGentry
Journal: Circulation Research (1978)

In pentobrabital-anesthetized open chest dogs, myocardial adenosine content is elevated by 5 or 15 seconds of left coronary artery occlusion and falls exponentially to control levels during reactive hyperemia. The rate constants for adenosine dissipation are (mean +/- SEM): -0.08 +/- 0.01 and -0.034 +/- 0.007 sec-1 after 5- and 15-second occlusion, respectively. Kinetic analysis of the reactive hyperemia flow curves (Circ Res 14/15 (suppl I): 81-85, 1963) predicts rates of -0.069 +/- 0.009 sec-1 and -0.04 +/- 0.009 sec-1, indicating that changes in adenosine levels can account for the way coronary flow changes during this response. The log (dose-) response curve relating reactive hyperemia flow to tissue adenosine concentration has a steeper slope and is half-maximal at a lower adenosine concentration than the dose-response curve obtained by intracoronary infusions of adenosine in oxygenated hearts, indicating that the coronary vasoactivity of adenosine is enhanced during reactive hyperemia. This could ex...
Pregnancy in cyanotic congenital heart disease. Outcome of mother and fetus.
Authors: PPresbitero, JSomerville, SStone, EAruta, DSpiegelhalter, FRabajoli
Journal: Circulation (1994)

In a series of 416 women with congenital heart disease seen in the Royal Brompton National Heart and Lung Hospital, London, and the Hospital Giovanni Bosco, Torino, Italy, there were 822 pregnancies. The outcomes of 96 pregnancies in 44 patients with cyanotic congenital heart disease were studied. Patients with the Eisenmenger reaction were excluded. Patients were divided arbitrarily into groups according to the type of maternal congenital cardiac anomaly, and factors influencing maternal and fetal outcome were evaluated. The incidence of maternal cardiovascular complications was high (32%), with one death from endocarditis 2 months after delivery. Forty-one (43%) of 96 pregnancies resulted in a live birth; 15 (37%) were premature. Mean weight of full-term infants was 2575 g. Univariate analysis suggested that maternal disease, Ability Index, hemoglobin, and arterial oxygen saturation before the pregnancy were factors that discriminated between successful and unsuccessful fetal outcome, with hemoglobin an...
Spontaneous occurrence of symptomatic paroxysmal atrial fibrillation and paroxysmal supraventricular tachycardia in untreated patients.
Authors: W KClair, W EWilkinson, E AMcCarthy, R LPage, E LPritchett
Journal: Circulation (1993)

BACKGROUNDAmbulatory outpatients (n = 150) with a history of paroxysmal supraventricular arrhythmia were studied to establish the characteristics of the first recurrence of symptomatic tachycardia (time to first recurrence, heart rate during tachycardia, and observed rhythm that was regular versus irregular) when no antiarrhythmic drug was being taken. Baseline variables were examined to assess their impact on time to first recurrence: index arrhythmia (paroxysmal atrial fibrillation [n = 37] versus paroxysmal supraventricular tachycardia [n = 113]), age (mean +/- SD, 43.3 +/- 16.1 years), female sex (n = 71), or presence of other heart or lung disease (n = 53).METHODS AND RESULTSTranstelephonic monitoring of the ECG was used to document the rhythm during recurrences of symptomatic tachycardia. Time to first recurrence of symptomatic tachycardia and heart rate during tachycardia were measured, the observed rhythm was classified as irregular (consistent with paroxysmal atrial fibrillation) or regular (cons...
Artificial Intelligence (AI) Vs Endoscopists in Detection of Barrett’s Neoplasia
Authors: M Abdelrahim, M Saikou, N Maeda, E Hossain, A al-Kandari, A Para-Blanco, AS Yague, E Coron, A Repici, P Bhandari
Journal: Endoscopy (2021)

Aims We aimed to develop and validate an AI algorithm based on deep neural networks for detection of Barrett’s neoplasia, and compare its performance to endoscopists.
Effects of increasing intercellular resistance on transverse and longitudinal propagation in sheep epicardial muscle.
Authors: MDelmar, D CMichaels, TJohnson, JJalife
Journal: Circulation Research (1987)

Propagation in cardiac muscle is faster in the longitudinal than in the transverse axis of the cells. Yet, as a result of the larger upstroke velocity of action potentials propagating transversely, it has been suggested that longitudinal propagation is more vulnerable to block. To study the relation between conduction velocity and maximal upstroke velocity (Vmax), as well as the time course of conduction delay and block in the transverse vs. longitudinal direction, thin square pieces of sheep epicardial muscle were superfused with the cellular uncoupler heptanol (1.5 mM). Action potentials were recorded with microelectrodes at opposite corners of the preparation while stimulating alternately in the longitudinal or transverse direction with bipolar electrodes located at contralateral corners. In all cases, block occurred more promptly for transverse than for longitudinal propagation. The decrease in conduction velocity was greater than expected for Vmax decay and, in some cases, Vmax increased while conduc...