tbuckley/cabot-search huggingface dataset:
Magnetic resonance imaging of chronic myocardial infarcts in formalin-fixed human autopsy hearts.
Authors: J CHsu, G AJohnson, W MSmith, K AReimer, R EIdeker
Journal: Circulation (1994)

BACKGROUNDIn post-myocardial infarction patients, three-dimensional structure of the infarct as well as infarct size are likely to be important factors affecting mortality, cardiac function, and arrhythmias. Current morphological methods for determining three-dimensional infarct structure in autopsied hearts are inexact and time consuming. The cardiac magnetic resonance imaging techniques used in living patients have shown potential in determining infarct size and structure but have limited resolution for morphometric postmortem studies. The recent development of magnetic resonance microscopy raises the possibility that three-dimensional infarct structure can be quantified at microscopic levels in autopsied hearts. The purpose of this study was to determine the ability of magnetic resonance imaging at different spatial resolutions to differentiate infarcted from noninfarcted myocardium.METHODS AND RESULTSMagnetic resonance imaging was performed at 2.0 T on cross sections taken from 10 autopsied hearts con...
Effect of propranolol in postinfarction patients with mechanical or electrical complications.
Authors: C DFurberg, C MHawkins, ELichstein
Journal: Circulation (1984)

In post  subgroup analyses, a simple classification system for patients, based on the presence or absence of findings indicative of electrical and/or mechanical complications early during short-term hospitalization, was applied to the data from the Beta-Blocker Heart Attack Trial (BHAT). In the largest subgroup of BHAT patients who had no reported complications, the 25 month mortality was low and the observed benefit of propranolol therapy small. Patients with electrical complications only had intermediate mortality and a pronounced effect of treatment was observed. Those with mechanical complications had the highest mortality and experienced an intermediate relative benefit of beta-blocker treatment. They also reported the most adverse effects. Post hoc analyses should always be interpreted cautiously. It is important to determine whether these findings are present in other completed beta-blocker trials. On the basis of these analyses alone it is suggested that the present practice of prescribing be...
Inhibition of prostaglandin synthesis by indomethacin augments the renal vasodilator response to bradykinin in the anesthetized dog.
Authors: A JLonigro, M HHagemann, A HStephenson, C LFry
Journal: Circulation Research (1978)

It has been proposed that the increase in renal blood flow (RBF) produced by bradykinin (BK) is mediated or amplified by the intrarenal generation of prostaglandins. The present investigation was designed to explore these relationships further. In anesthetized dogs, the renal arterial infusion of BK (100 ng/kg per min), prior to the intravenous administration of indomethacin, produced a 93 +/- 14% increase in RBF and an increase in the renal venous concentration of a prostaglandin E-like substance (PGE) from 51 +/- 23 to 235 +/- 73 pg/ml as determined by bioassay. Following indomethacin (5 mg/kg), the same dose of BK produced a 151 +/- 18% increase in RBF (P less than 0.001 compared to the preindomethacin increase) and the concentration of PGE remained largely below the threshold of sensitivity of the bioassay system. In three experiments, a highly sensitive and specific radioimmunoassay technique was used to obtain better quantitative estimates of concentrations of E2-like (PGE2) and F2alpha-like (...
The relationship between age and relaxation of vascular smooth muscle in the rabbit and rat.
Authors: J HFleisch, C SHooker
Journal: Circulation Research (1976)

Relaxation of rabbit and rat aorta by isoproterenol decreases with increasing age, whereas such responses caused by nitroglycerin or sodium nitrite are not age-dependent. In the present study, we sought to determine whether this relationship also exists in pulmonary arteries and portal veins. As was the case with the aorta, isoproterenol-induced relaxation of pulmonary arteries decreased as the animal aged; relaxation by nitroglycerin was minimally altered. Aging did not influence responses of rabbit and rat portal veins to isoproterenol or nitroglycerin. If the responses of these blood vessels are characteristic of the responses of other vascular smooth muscles to vasodilators, then this study suggests a difference in the manner by which arteries and veins age. We also confirmed that isoproterenol-induced relaxation of rabbit and rat aorta markedly decreases with increasing age and that the responses of rat aorta to nitroglycerin are independent of age. Because of the agonist used to contract the tissues...
Site of myocardial infarction. A determinant of the cardiovascular changes induced in the cat by coronary occlusion.
Authors: P BCorr, D LPearle, J RHinton, W CRoberts, R AGillis
Journal: Circulation Research (1976)

The influence of site of acute myocardial infarction on heart rate, blood pressure, cardiac output, total peripheral resistance (TPR), cardiac rhythm, and mortality was determined in 58 anesthetized cats by occlusion of either the left anterior descending (LAD), left circumflex or right coronary artery. LAD occlusion resulted in immediate decrease in cardiac output, heart rate, and blood pressure, an increase in TPR, and cardiac rhythm changes including premature ventricular beats, ventricular tachycardia, and occasionally ventricular fibrillation. The decrease in cardiac output and increase in TPR persisted in the cats surviving a ventricular arrhythmia. In contrast, right coronary occlusion resulted in a considerably smaller decrease in cardiac output. TPR did not increase, atrioventricular condition disturbances were common, and sinus bradycardia and hypotension persisted in the cats recovering from an arrhythmia. Left circumflex ligation resulted in cardiovascular changes intermediate between those pr...
Exercise training improves left ventricular systolic function in older men.
Authors: A AEhsani, TOgawa, T RMiller, R JSpina, S MJilka
Journal: Circulation (1991)

To determine whether endurance exercise training can improve left ventricular systolic function in older men, 10 healthy sedentary men (64 +/- 3 years old; mean +/- SD) were studied. Training consisted of endurance exercise 4 +/- 0.3 days per week for 11.8 +/- 2.5 months at a progressively increasing intensity of 60-80% of maximal O2 uptake (Vo2max) with additional brief bouts of exercise equal to 93 +/- 13% of Vo2max. Vo2max increased from 29.6 +/- 4.1 to 37.2 +/- 5.7 ml/kg/min (p less than 0.001). Percent body fat was decreased (17.8 +/- 3.6% versus 15.6 +/- 3.6%; p less than 0.001). Before training, left ventricular ejection fraction, determined by electrocardiographic-gated equilibrium blood pool imaging, increased only modestly during exercise (from 66.3 +/- 6.7% at rest to 70.6 +/- 6.9% at peak exercise). After training, the increase in ejection fraction during exercise was significantly greater (from 67 +/- 4.8% at rest to 77.6 +/- 7.5% at peak exercise) than that observed before training and was s...
Exercise cardiac output is maintained with advancing age in healthy human subjects: cardiac dilatation and increased stroke volume compensate for a diminished heart rate.
Authors: R JRodeheffer, GGerstenblith, L CBecker, J LFleg, M LWeisfeldt, E GLakatta
Journal: Circulation (1984)

To assess the effect of age on cardiac volumes and function in the absence of overt or occult coronary disease, we performed serial gated blood pool scans at rest and during progressive upright bicycle exercise to exhaustion in 61 participants in the Baltimore Longitudinal Study of Aging. The subjects ranged in age from 25 to 79 years and were free of cardiac disease according to their histories and results of physical, resting and stress electrocardiographic, and stress thallium scintigraphic examinations. Absolute left ventricular volumes were obtained at each workload. There were no age-related changes in cardiac output, end-diastolic or end-systolic volumes, or ejection fraction at rest. During vigorous exercise (125 W), cardiac output was not related to age (cardiac output [1/min] = 16.02 + 0.03 [age]; r = .12, p = .46). However, there was an age-related increase in end-diastolic volume (end-diastolic volume [ml] = 86.30 + 1.48 [age]; r = .47, p = .003) and stroke volume (stroke volume [ml] = 85.52 +...
Response to Letter Regarding Article, “Comparison of Transplacental Treatment of Fetal Supraventricular Tachyarrhythmias With Digoxin, Flecainide, and Sotalol: Results of a Nonrandomized Multicenter Study”
Authors: Nico A. Blom, Ernestine De Groot, Edgar T. Jaeggi, Brian W. McCrindle, Cedric Manlhiot, Julene S. Carvalho, Olus Api, Sally-Ann B. Clur, Lukas Rammeloo, Greg Ryan
Journal: Circulation (2012)
Opioid Use Increases the Risk of Delirium in Critically Ill Adults Independently of Pain
Authors: Matthew S. Duprey, Sandra M. A. Dijkstra-Kersten, Irene J. Zaal, Becky A. Briesacher, Jane S. Saczynski, John L. Griffith, John W. Devlin, Arjen J. C. Slooter
Journal: American Journal of Respiratory and Critical Care Medicine (2021)

Rationale: It is unclear whether opioid use increases the risk of ICU delirium. Prior studies have not accounted for confounding, including daily severity of illness, pain, and competing events that may preclude delirium detection.Objectives: To evaluate the association between ICU opioid exposure, opioid dose, and delirium occurrence.Methods: In consecutive adults admitted for more than 24 hours to the ICU, daily mental status was classified as awake without delirium, delirium, or unarousable. A first-order Markov model with multinomial logistic regression analysis considered four possible next-day outcomes (i.e., awake without delirium, delirium, unarousable, and ICU discharge or death) and 11 delirium-related covariables (baseline: admission type, age, sex, Acute Physiology and Chronic Health Evaluation IV score, and Charlson comorbidity score; daily: ICU day, modified Sequential Organ Failure Assessment, ventilation use, benzodiazepine use, and severe pain). This model was used to quantify the association between opioid use, opioid dose, and delirium occurrence the next day.Measurements and Main Results: The 4,075 adults had 26,250 ICU days; an opioid was administered on 57.0% (n = 14,975), severe pain occurred on 7.0% (n = 1,829), and delirium occurred on 23.5% (n = 6,176). Severe pain was inversely associated with a transition to delirium (odds ratio [OR] 0.72; 95% confidence interval [CI], 0.53-0.97). Any opioid administration in awake patients without delirium was associated with an increased risk for delirium the next day [OR, 1.45; 95% CI, 1.24-1.69]. Each daily 10-mg intravenous morphine-equivalent dose was associated with a 2.4% increased risk for delirium the next day.Conclusions: The receipt of an opioid in the ICU increases the odds of transitioning to delirium in a dose-dependent fashion.
Noninvasive determination of age-related changes in the human arterial pulse.
Authors: RKelly, CHayward, AAvolio, MO'Rourke
Journal: Circulation (1989)

Arterial pressure waves were recorded noninvasively from the carotid, radial, femoral, or all three of these arteries of 1,005 normal subjects, aged 2-91 years, using a new transcutaneous tonometer containing a high fidelity Millar micromanometer. Waves were ensemble-averaged into age-decade groups. Characteristic changes were noted with increasing age. In all sites, pulse amplitude increased with advancing age (carotid, 91.3%; radial 67.5%; femoral, 50.1% from first to eighth decade), diastolic decay steepened, and diastolic waves became less prominent. In the carotid pulse, there was, in youth, a second peak on the downstroke of the waves in late systole. After the third decade, this second peak rose with age to merge with and dominate the initial rise. In the radial pulse, a late systolic wave was also apparent, but this occurred later; with age, this second peak rose but not above the initial rise in early systole, even at the eighth decade. In the femoral artery, there was a single systolic wave at a...
Hemodynamic assessment after palliative surgery for hypoplastic left heart syndrome.
Authors: PLang, W INorwood
Journal: Circulation (1983)

Ten patients with hypoplastic left heart syndrome underwent cardiac catheterization to assess the effectiveness of palliative surgery designed to prepare them for a modified Fontan procedure. The objectives of palliation were to establish unobstructed systemic blood flow, normalize pulmonary blood flow and pressure, and relieve pulmonary venous obstruction. In the first four patients, systemic blood flow from the right ventricle was established by means of a conduit from either the right ventricular free wall or the proximal main pulmonary artery to the thoracic aorta. Pulmonary blood flow was limited by pulmonary artery banding and ligation of the ductus arteriosus in three patients and by a Blalock-Taussig shunt in one. Conduit obstruction of systemic blood flow developed in two of these infants, and pulmonary vascular abnormalities precluded reparative surgery in the other two. In the other six patients, systemic blood flow was established by direct anastomosis of the proximal main pulmonary artery to ...
Heat-shock response and limitation of tissue necrosis during occlusion/reperfusion in rabbit hearts.
Authors: R WCurrie, R MTanguay, J GKingma
Journal: Circulation (1993)

BACKGROUNDInduction of stress proteins, such as heat-shock protein 71 (HSP71), is associated with cardioprotection in isolated ischemic myocardium. We tested this hypothesis in rabbits pretreated with whole-body hyperthermia and then subjected to 30 or 45 minutes of regional coronary occlusion (CO) followed by 3 hours reperfusion (Rep).METHODS AND RESULTSControl rabbits did not undergo whole-body hyperthermia; heat-shocked (HS) rabbits were subjected to whole-body hyperthermia at 42 degrees C for 15 minutes. Rabbits were allowed to recover from whole-body hyperthermia for 24 or 40 hours and were then subjected to CO/Rep. Heart rate and arterial blood pressure were recorded during the experiments. Area of necrosis (tetrazolium staining) was normalized to anatomic risk zone size (microsphere autoradiography). In rabbits treated with whole-body hyperthermia and 24 hours of recovery, infarct size was significantly reduced in HS rabbits compared with control rabbits (41.2 +/- 7.8% versus 23.2 +/- 6.6%; p < or ...
Use of atropine in patients with acute myocardial infarction and sinus bradycardia.
Authors: M MScheinman, DThorburn, J AAbbott
Journal: Circulation (1975)

Fifty-six patients with acute myocardial infarction complicated by sinus bradycardia (SB) were treated with intravenous atropine and monitored in a coronary care unit. Atropine decreased or completely abolished premature ventricular contractions (PVCs) and/or bouts of accelerated idioventricular rhythm in 27 of 31 patients (87%) and brought systemic blood pressure up to normal in 15 of 17 patients (88%) with hypotension. In addition, atropine administration was associated with improved atrioventricular conduction in 11 of 13 patients (85%) with acute inferior myocardial infarction associated with 2 degrees or 3 degrees atrioventricular block. Seven patients developed ten significant adverse effects: ventricular tachycardia or fibrillation in three, sustainedsinus tachycardia in three, increased PVCs in three, and toxic psychosis in one. These major adverse effects correlated with either a higher initial dose of atropine (i.e., 1.0 mg aa compared with the usual 0.5 or 0.6 mg) or a total cumulative dose exc...
Anti-cholinergic effects of quinidine, disopyramide, and procainamide in isolated atrial myocytes: mediation by different molecular mechanisms.
Authors: TNakajima, YKurachi, HIto, RTakikawa, TSugimoto
Journal: Circulation Research (1989)

Effects of quinidine, disopyramide, and procainamide on the acetylcholine (ACh)-induced K+ channel current were examined in single atrial cells, using the tight-seal, whole-cell clamp technique. The pipette solution contained guanosine-5'-triphosphate (GTP) or guanosine-5'-O-(3-thiotriphosphate) (GTP-gamma S, a nonhydrolysable GTP analogue). In GTP-loaded cells, not only ACh but also adenosine induced a specific K+ channel current via GTP-binding proteins (G) by activating muscarinic ACh or adenosine receptors. Quinidine and disopyramide depressed the ACh-induced K+ current quite effectively. Procainamide had a weak inhibitory effect. Quinidine also depressed adenosine-induced K+ current, while the effect of disopyramide on adenosine-induced current was much smaller than that on ACh-induced current. In GTP-gamma S-loaded cells, the K+ channel was uncoupled from the receptors and was activated irreversibly, probably due to direct activation of G proteins by GTP-gamma S. Quinidine depressed the GTP-gamma S-...
Safety of the Use of Radioactive Iodine in Patients With Hyperthyroidism
Authors: Erin E. Grady, Katherine Zukotynski, Bennett S. Greenspan
Journal: JAMA Internal Medicine (2019)

To the Editor As representatives of the American College of Nuclear Medicine, we wish to comment on a recent Original Investigation by Kitahara and colleagues1 that has indirectly called into question the safety of the use of sodium iodide I-131, also known as radioactive iodine (RAI).
Purification of human angiotensinogen.
Authors: D ATewksbury, M RPremeau, M LDumas, W LFrome
Journal: Circulation Research (1977)

A four-step method for the purification of human angiotensinogen has been devised. The four steps are: (1) removal of albumin by affinity chromatography on blue dextran-Sepharose, (2) chromatography on DEAE-Sephadex, (3) chromatography on hydroxylapatite, and (4) chromatography on DEAE-cellulose. This method is capable of producing 8 mg of purified angiotensinogen from 150 ml of plasma with 33% overall recovery of renin-releasable angiotensin I. The angiotensinogen appears homogeneous by immunochemical and ultracentrifugal techniques. The N-terminal amino acids have been determined to be alanine and aspartic acid or asparagine.
Blood‐Compatible Materials: Blood‐Compatible Materials: Vascular Endothelium‐Mimetic Surfaces that Mitigate Multiple Cell‐Material Interactions (Adv. Healthcare Mater. 7/2021)
Authors: Jessica R. Vlcek, Mohammadhasan Hedayati, Alyssa C. Melvin, Melissa M. Reynolds, Matt J. Kipper
Journal: Advanced Healthcare Materials (2021)

In article number 2001748 by Matt J. Kipper and co-workers, nanostructured surfaces that mimic features of the blood vessel wall and that deliver nitric oxide can be tuned to favorably influence cell-surface interactions with platelets, leukocytes, and bacteria. These surfaces could be used to develop advanced blood-compatible materials.
Regulation of angiotensin II receptors on ventricular myocytes after myocardial infarction in rats.
Authors: L GMeggs, JCoupet, HHuang, WCheng, J MCapasso, C JHomcy, PAnversa
Journal: Circulation Research (1993)

To determine the effects of acute myocardial infarction on the regulation of angiotensin II (Ang II) receptors and contractile performance of left and right ventricular myocytes, coronary artery ligation was surgically induced in rats, and Ang II receptor density and affinity and the mechanical properties of surviving muscle cells were examined 1 week later. Physiological determinations of cardiac pump function revealed the presence of ventricular failure, which was associated at the cellular level with a depression in the velocity of myocyte shortening and relengthening, a prolongation of time to peak shortening, and a reduction in the extent of cell shortening. These abnormalities in single-cell function were more prominent in left than in right ventricular myocytes. Cellular hypertrophy was documented by increases in cell length and width, which were also greater in the spared myocytes of the infarcted left ventricle. Reactive hypertrophy was accompanied by a 1.84- and 1.85-fold increase in the density...
Higher Ca2+ sensitivity of triton-skinned guinea pig mesenteric microarteries as compared with large arteries.
Authors: P JBoels, MTroschka, J CRüegg, GPfitzer
Journal: Circulation Research (1991)

Small mesenteric resistance arteries and the main branch of the mesenteric artery (outer in situ diameter 115 +/- 3 microns [n = 76] and greater than 1,000 microns, respectively) were skinned with 1% Triton X-100. Both preparations were mounted as rings for circumferential force measurement in an EGTA solution (free Ca2+, less than 10 nM; calmodulin, 0.3 microM; pH 6.7). Force-pCa curves were obtained by increasing free Ca2+ (0.05 to 30 microM). The resulting dose-dependent contractions, after normalization to maximal force development (arteries, 21.4 +/- 2.4 [n = 3]; arterioles, 15.3 +/- 2.1 mN/mm2 [n = 5]) were fitted to sigmoidal force-pCa curves. Values of ED50 and of the cooperativity factor h were 6.08 and 2.39 in arterioles and 5.64 and 1.64 in arteries. The higher Ca2+ sensitivity of arteriolar preparations remained at pH 7.0 at higher calmodulin concentrations and after inhibition of smooth muscle phosphatase with okadaic acid. Total myosin light chain kinase activity in crude arteriolar extracts...
Effect of positive inotropic agents on myosin isozyme population and mechanical activity of cultured rat heart myocytes.
Authors: HRupp, H JBerger, APfeifer, KWerdan
Journal: Circulation Research (1991)

To examine whether catecholamines have a direct effect on myosin heavy chain expression of heart myocytes or whether they act via an altered work load, myocytes from neonatal rat hearts were cultured in thyroid hormone-free media containing various positive inotropic and chronotropic agents. The velocity and frequency of contraction of the myocytes were monitored using an optoelectronic system. After 3-5 days of culture, myosin isozyme populations, cellular cAMP content, and 2-deoxy-D-glucose uptake of the myocytes were determined. Compared with myocytes cultured in the absence of inotropic agents (32.6 +/- 3.5% V1), the proportion of myosin V1 was significantly (p less than 0.05) increased in the case of 1 microM isoproterenol (48.2 +/- 5.9% V1), 1 microM forskolin (57.1 +/- 11.7% V1), and 1 mM dibutyryl cAMP (79.1 +/- 2.0% V1). Dibutyryl cAMP increased V1 to a similar level as 30 nM triiodothyronine did (70.2 +/- 13.0% V1). Only a small increase was observed in myocytes cultured in the presence of 10 mi...
Time course of functional improvement in stunned myocardium in risk area in patients with reperfused anterior infarction.
Authors: HIto, TTomooka, NSakai, YHigashino, KFujii, OKatoh, TMasuyama, AKitabatake, TMinamino
Journal: Circulation (1993)

BACKGROUNDThe beneficial effect of coronary reflow on myocardial salvage may be assessed more accurately than in previous studies if the size of risk area is taken into account, particularly because the size of risk area varies significantly among patients. In this study, the risk area was determined with myocardial contrast echocardiography to investigate the time course of functional recovery of postischemic myocardium within the risk area in patients with reperfused anterior myocardial infarction.METHODS AND RESULTSThe study population consisted of 21 patients with anterior myocardial infarction who achieved coronary reflow within 6 hours of onset by means of thrombolysis or coronary angioplasty. Myocardial contrast echocardiography was performed with the injection of hand-agitated Haemaccel (5 ml) into the right and left coronary arteries before coronary reflow, and the risk area was defined as the area of contrast perfusion defect in the apical long-axis view. The ratio of the endocardial length of a...