tbuckley/cabot-search huggingface dataset:
Assessment of left atrial appendage function by transesophageal echocardiography. Implications for the development of thrombus.
Authors: CPollick, DTaylor
Journal: Circulation (1991)

BACKGROUNDThe predilection of the left atrial appendage (LAA) for thrombus formation has long been known.METHODS AND RESULTSWe prospectively studied the two-dimensional echocardiographic and Doppler patterns of LAA function in 82 patients by transesophageal echocardiography. In the 63 patients in sinus rhythm, LAA area was measured during LAA diastole at the onset of the electrocardiographic (ECG) P wave (LAAmax) and after LAA systole at the ECG R wave (LAAmin) and LAA ejection fraction was calculated as (LAAmax-LAAmin)/LAAmax; peak Doppler velocity was recorded from the LAA outlet. The 58 patients in sinus rhythm without LAA thrombus were grouped according to left atrial size on transthoracic echocardiography; 39 patients had a left atrial size of less than 40 mm (group 1) and 19 had a left atrial size of 40 mm or greater (group 2). Five patients in sinus rhythm had LAA thrombus. In the 19 patients with atrial fibrillation or flutter LAAmax was measured independent of the ECG; three of these patients had...
Metabolic studies in mitral valve prolapse syndrome. A neuroendocrine--cardiovascular process.
Authors: HBoudoulas, J CReynolds, EMazzaferri, C FWooley
Journal: Circulation (1980)

Symptomatic patients with mitral valve prolapse (MVP) frequently mimic thyrotoxicosis, hyperadrenergic states or hypoglycemia. Twenty symptomatic patients with auscultatory and echocardiographic MVP were studied in the clinical research unit. T3, T4 and plasma cortisol were normal. Patients with MVP had normal responses to oral glucose administration but higher glucose levels than the controls (p less than 0.05). Twenty-four-hour urinary epinephrine (E) and norepinephrine (NE) were greater than normal (E + NE excretion, 44 +/- 2 vs 29.5 microgram/g creatinine, p less than 0.001). The short electromechanical systole corrected for heart rate (529 +/- 3.9 vs normal 548 +/- 2 msec, p less than 0.01) also reflected high adrenergic tone. Frequent premature ventricular complexes (PVCs) with couplets and triplets were found in 14 patients. Catecholamine excretion and frequency of PVCs were parallel and both decreased significantly at night (p less than 0.001). Plasma catecholamine increase with exercise was great...
Measurement of infarct size and percentage myocardium infarcted in a dog preparation with single photon-emission computed tomography, thallium-201, and indium 111-monoclonal antimyosin Fab.
Authors: L LJohnson, K SLerrick, JCoromilas, D WSeldin, P DEsser, J MZimmerman, A MKeller, P OAlderson, J TBigger, P JCannon
Journal: Circulation (1987)

Single photon-emission tomography (SPECT) and indium 111-labeled monoclonal antimyosin Fab fragments were used to measure myocardial infarct size in 12 dogs, six subjected to balloon catheter-induced coronary artery occlusion for 6 hr (late reperfusion) and six subjected to occlusion with reperfusion at 2 hr (early reperfusion). Tomographic imaging was performed 24 hr after the intravenous injection of labeled Fab fragments with the use of a dual-head SPECT camera with medium-energy collimators. Immediately after the first tomographic scan, thallium-201 was injected into nine of 12 dogs and imaging was repeated. Estimated infarct size in grams was calculated from transaxially reconstructed, normalized, and background-corrected indium SPECT images with the use of a threshold technique for edge detection. Estimated noninfarcted myocardium in grams was calculated from obliquely reconstructed thallium SPECT images by a similar method. The animals were killed and infarct size in grams and true infarct size as ...
Development and clinical validation of loop-mediated isothermal amplification (LAMP) assay to diagnose high HBV DNA levels in resource-limited settings
Authors: Jessica Vanhomwegen, Aurélia Kwasiborski, Abou Diop, Laure Boizeau, Damien Hoinard, Muriel Vray, Raymond Bercion, Babacar Ndiaye, Amélie Dublineau, Satoru Michiyuki, Jean-Claude Manuguerra, Virginie Sauvage, Daniel Candotti, Abdoulaye Seck, Syria Laperche, Yusuke Shimakawa
Journal: Clinical Microbiology and Infection (2021)
Different electrical responses to vasoactive agonists in morphologically distinct smooth muscle cell types.
Authors: C BNeylon, P VAvdonin, R JDilley, M ALarsen, V ATkachuk, ABobik
Journal: Circulation Research (1994)

Vascular smooth muscle cells (SMCs) in the blood vessel wall are frequently heterogeneous in nature, differing in their gross morphology, size, and shape, subcellular organelles, cytoskeleton, and contractile protein composition. In adult rat arterial vessels, two populations of SMCs have been shown to predominate: elongated bipolar cells, representing the majority of cells, and epithelial-like SMCs. We examined the ionic responses of these two types of SMCs, isolated by multiple subculture, to vasoactive stimuli. Elevations in intracellular Na+ and Ca2+ were measured with SBFI and fura 2, respectively, and changes in membrane potential were measured using the potential-sensitive fluorescent probe bis-oxonol. The resting membrane potential of the elongated bipolar cells was less negative than that of the epithelial-like SMCs. Exposure of the elongated SMCs to endothelin 1, alpha-thrombin, or arginine vasopressin induced elevations in [Ca2+]i and [Na+]i and membrane depolarization. Depolarization occurred ...
Comparison of Therapy in Advanced Hepatocellular Carcinoma Based on Clear Definition and Accurate Subgroup Data—Reply
Authors: Mohamad Bassam Sonbol, Irbaz Bin Riaz, Tanios Bekaii-Saab
Journal: JAMA Oncology (2021)

Our website uses cookies to enhance your experience. By continuing to use our site, or clicking "Continue," you are agreeing to our Cookie Policy | Continue JAMA Oncology HomeNew OnlineCurrent IssueFor Authors Podcast Publications JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry (1919-1959) JN Learning / CMESubscribeJobsInstitutions / LibrariansReprints & Permissions Terms of Use | Privacy Policy | Accessibility Statement 2023 American Medical Association. All Rights Reserved Search All JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Forum Archive JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry Input Search Term Sign In Individual Sign In Sign inCreate an Account Access through your institution Sign In Purchase Options: Buy this article Rent this article Subscribe to the JAMA Oncology journal
Effects of low-dose dobutamine on coronary hemodynamics, myocardial metabolism, and anginal threshold in patients with coronary artery disease.
Authors: IPacold, BKleinman, RGunnar, H SLoeb
Journal: Circulation (1983)

Fourteen patients with coronary artery disease and normal or near-normal left ventricular function were studied at rest and during atrial pacing until the occurrence of angina (12 patients) before and during infusion of dobutamine (3.80 +/- 0.45 micrograms/kg/min). At rest, during the infusion, three patients developed chest pain, mean ST segment depression increased from 0.02 to 0.08 mV (p less than .001), and myocardial lactate extraction fell from +17.5% to -1.4% (p less than .05). These ischemic changes were associated with significant increases in arterial systolic pressure (134 to 149 mm Hg), heart rate (79 to 91 beats/min), coronary sinus flow (89 to 113 ml/min), and myocardial oxygen consumption (10.8 to 13.5 cc/min). In contrast, during atrial pacing, dobutamine did not reduce the pacing threshold or further increase myocardial oxygen consumption or ST segment changes; however, arterial mean and diastolic pressures were significantly lower with pacing during dobutamine infusion compared with cont...
Low density lipoprotein transport across a microvascular endothelial barrier after permeability is increased.
Authors: J CRutledge, F RCurry, J FLenz, P ADavis
Journal: Circulation Research (1990)

We investigated the pathways for low density lipoprotein (LDL) transport across an endothelial barrier in individually perfused microvessels before and after an increase in permeability. The divalent cation ionophore A23187 (5 microM) was used to increase microvessel permeability. LDL permeability coefficients (PsLDL) were measured using quantitative fluorescence microscopy. In the control state, PsLDL measured after 10-23 minutes of accumulation of fluorescent-labeled LDL outside the microvessel wall was 4.8 x 10(-8) cm/sec. The transvascular vesicular exchange of approximately 50 vesicles/sec would account for the measured flux. The flux of LDL across the microvessel wall increased as much as 170-fold at the peak of the permeability increase (2-4 minutes after ionophore infusion). Permeability returned toward control values 10 minutes after ionophore infusion but remained elevated for as long as ionophore was present in the perfusate. The effective PsLDL was similar in magnitude to the Ps for fluorescen...
Radiofrequency catheter ablation of the atrioventricular junction from the left ventricle.
Authors: JSousa, Rel-Atassi, SRosenheck, HCalkins, JLangberg, FMorady
Journal: Circulation (1991)

BACKGROUNDThe purpose of this study was to describe a new technique for catheter ablation of the atrioventricular junction using radiofrequency energy delivered in the left ventricle.METHODS AND RESULTSCatheter ablation of the atrioventricular (AV) junction using a catheter positioned across the tricuspid annulus was unsuccessful in eight patients with a mean +/- SD age of 51 +/- 19 years who had AV nodal reentry tachycardia (three patients), orthodromic tachycardia using a concealed midseptal accessory pathway, atrial tachycardia, atrial flutter (two patients), or atrial fibrillation. Before attempts at catheter ablation of the AV junction, each patient had been refractory to pharmacological therapy, and four had failed attempts at either catheter modification of the AV node using radiofrequency energy or surgical and catheter ablation of the accessory pathway. Conventional right-sided catheter ablation of the AV junction using radiofrequency energy in six patients and both radiofrequency energy and dire...
Contractile and morphological impairment of cultured fetal mouse myocytes induced by oxygen radicals and oxidants. Correlation with intracellular Ca2+ concentration.
Authors: T YNakamura, KGoda, TOkamoto, TKishi, TNakamura, KGoshima
Journal: Circulation Research (1993)

There is evidence that reperfusion injury of cardiac tissue may be caused by the generation of oxygen-derived free radicals and oxidants and by the induction of intracellular calcium overload, although the relation between these two mechanisms of injury is uncertain. In addition, the relation between the types of cellular injury and specific active species is unclear. In an attempt to resolve these problems, we investigated the effects of oxygen radicals and oxidants, which are purportedly generated during reperfusion after prolonged ischemia, and various antioxidants on contractility and morphology of cultured fetal mouse cardiac myocytes. Xanthine oxidase in the presence of xanthine, H2O2, HOCl, and NH2Cl induced cessation of spontaneous beating followed by cessation of electrical stimulation-elicited beating but did not induce an increase in [Ca2+]i. After prolonged incubation with xanthine oxidase + xanthine and H2O2, the cardiac myocytes showed morphological degeneration (at least 80% of the cells de...
You can’t stop the bleep
Authors: Kamran Abbasi
Journal: BMJ (2021)

On my first day at The BMJ the biggest shock to my system, other than the editor depositing a tall pile of research papers on my desk, was not being "bleeped."I'd often worry I was missing something important.As a new doctor the bleep is a validation of your efforts to join an esteemed profession.It is a status symbol you soon tire of; any moment of peace will be broken by a buzz heralding anything from the mundane to the calamitous.
The syndrome of variant angina culminating in acute myocardial infarction.
Authors: J EMadias
Journal: Circulation (1979)

Ten patients 28-54 years old with recurrent attacks of variant angina (chest pain associated with transient ST-segment elevation) culminating in acute myocardial infarction were studied. Systemic blood pressure and heart rate remained unchanged or decreased during chest pain. Diagnosis of myocardial infarction was made on the basis of pathognomonic enzyme changes and T-wave inversions persisting for several weeks (seven patients) or development of Q waves (three patients). Complications were similar to the ones previously observed in conventional myocardial infarction. None of these patients died. Past history was characterized by absence of effort angina. Exercise stress testing after infarction was normal, and coronary arteriography revealed a spectrum of pathology, ranging from normal arteriograms to three-vessel disease. Intraaortic balloon pumping was ineffective in two patients, but subsequent coronary bypass surgery shortly after myocardial infarction was not followed by further attacks of chest pa...
Covid-19 as a Barrier for Delaying Therapeutic Endoscopy After Radical Treatment of Upper Gastrointestinal Cancer. Analysis of Clinical Cases
Authors: O Basina, A Lapina, A Sivins, A Kaminskis
Journal: Endoscopy (2021)

Aims We decided to present several patient's cases that had several therapeutic endoscopies and follow ups after radical treatment of upper gastrointestinal cancer, as well as point out the problems associated with treatment delay due to COVID-19 pandemic.
Prediction of the normal blood volume. Relation of blood volume to body habitus.
Authors: JFeldschuh, YEnson
Journal: Circulation (1977)

Predictions of blood volume (BV) assume the existence of a constant ratio between BV and body weight or surface area (SA). We examined the validity of this assumption by calculating BV from plasma volume and body hematocrit in 160 normal volunteers whose weights ranged from -38.7 to 210.8% of desirable weight (assessed by a modification of the Metropolitan Life Insurance Company Desirable Weight tables). BV is not a constant fraction of body weight or SA in this population. Its prediction from such constant ratios results in a large error of estimate which is systematically biased with respect to height and weight. BV prediction from the observed regressions of the parameter on weight and SA reduces the error substantially but remains biased with respect to height. BV prediction from the subject's degree of deviation from desirable weight affords a smaller error of estimate which is apparently free from systematic bias.
Canine ventricular arrhythmias in the late myocardial infarction period. 8. Epicardial mapping of reentrant circuits.
Authors: NEl-Sherif, R ASmith, KEvans
Journal: Circulation Research (1981)

We made simultaneous recordings from 48 bipolar electrodes to obtain epicardial isochronal maps during induced ventricular arrhythmias in dogs 3-5 days after ligation of the left anterior descending artery. There was strong evidence of a reentrant circuit (RC) that was discernible largely on the epicardial surface in 21% of ectopic beats that were analyzed. Epicardial recordings were of limited value in analyzing the arrhythmia in other beats. The reentrant circuit consisted of an arc of conduction block around which the activation front advanced in a circular fashion at slow but uneven speeds while the rest of the ventricle was activated by radial spread. The arc of conduction block around which the RC was formed was usually functional in nature, since the same area of myocardium was excitable at relatively long cardiac cycle lengths. Both the length of the arc of conduction block which defines the length of the reentrant circuit and the degree of conduction delay were crucial factors for the occurrence ...
New vectorcardiographic criteria for diagnosing right ventricular hypertrophy in mitral stenosis: comparison with electrocardiographic criteria.
Authors: C DCowdery, G SWagner, J WStarr, GRogers, J CGreenfield
Journal: Circulation (1980)

Frank-lead vectorcardiograms (VCGs) and standard 12-lead electrocardiograms (ECGs) were analyzed to develop simple, linear, quantitative criteria for the diagnosis of right ventricular hypertrophy (RVH). The study subjects included a population with a definite RVH (84 patients with mitral stenosis proved by cardiac catheterization and pulmonary arterial systolic pressure > 40 mm Hg) and a population with minimal likelihood of RVH (173 young, healthy volunteers and 151 normal subjects proved by cardiac catheterization). VCGs were evaluated to identify criteria that provided maximum sensitivity and at least a 95% specificity: the maximum QRS magnitude had to be < 1.8 mV and either (1) the amplitude at -45 degrees (transverse plane) had to be < 0.3 mV or (2) the maximum anterior amplitude plus the maximum rightward amplitude minus the amplitude at -45 degrees must be greater than or equal to 0.5 mV. Application of these criteria achieved 60% (50 of 84) sensitivity in patients with RVH, similar to that for pr...
Efficacy of platelet depletion in counteracting the detrimental effect of acute hypercholesterolemia on infarct size and the no-reflow phenomenon in rabbits undergoing coronary artery occlusion-reperfusion.
Authors: PGolino, P RMaroko, T ECarew
Journal: Circulation (1987)

It has recently been demonstrated that acute hypercholesterolemia per se, independently of its atherogenic effect, increases the extent of myocardial injury in rabbits undergoing coronary artery occlusion-reperfusion. Estimation of myocardial blood flow after reperfusion indicated that this deleterious effect was due to a vascular obstruction that limited the efficacy of reperfusion. The goal of this study was to evaluate the role played by platelets in contributing to the occurrence of this deleterious effect. Accordingly, New Zealand White rabbits were fed a standard laboratory chow diet (plasma cholesterol 67 +/- 12 mg/dl) or a 2% cholesterol-enriched diet for 3 days (plasma cholesterol 329 +/- 70 mg/dl). In a first series of experiments autologous platelets were labeled with 111In-oxine. After labeling, platelets were reinjected in the same animal and 30 min later coronary artery occlusion (CAO) was induced. CAO was maintained for 30 min followed by 5.5 hr of reperfusion. The animals were then killed,...
Effect of phalloidin on structure and permeability of rete capillaries in the normal and hypoxic state.
Authors: E ARasio, MBendayan, C AGoresky, J SAlexander, DShepro
Journal: Circulation Research (1989)

The effects of 10(-6) M phalloidin on reperfusion-injured blood capillary structure and permeability were studied in the countercurrent perfused rete mirabile of the eel swim bladder. In the normal rete, the addition of phalloidin to the perfusion medium did not induce morphological or functional changes. When flow was arrested for 30 minutes, during which time the capillaries were exposed to inhibitors of ATP generation, and flow was then resumed with an oxygenated medium, cell membrane blebs and vacuolization, mitochondrial swelling, pericyte shrinkage, and interstitial space edema were observed. The permeability coefficients for labeled albumin, sucrose, and sodium increased to three to four times baseline values, whereas the permeability to water was not significantly modified. When the same protocol was repeated with phalloidin present in the medium throughout the experiment, the structural integrity of the endothelial cells was completely preserved and pericyte shrinkage was abolished, but interstit...
Alleviation of myocardial stunning by leukocyte and platelet depletion.
Authors: WWestlin, K MMullane
Journal: Circulation (1989)

Neutrophils accumulate in myocardium rendered ischemic and reperfused. Activated neutrophils release mediators such as metabolites of oxygen that can compromise myocellular integrity and provoke cardiac dysfunction. Although it is established that leukopenia reduces infarct size, the role of leukocytes and the source of free radicals in postischemic contractile dysfunction is unresolved. A carotid left anterior descending coronary-artery extracorporeal circuit without (n = 8) or with a Leukopak filter (n = 6) to deplete the leukocytes and platelets from blood entering the left anterior descending artery was established in the anesthetized, open-chest dog 30 minutes before ischemia. Subendocardial segmental function was monitored by sonomicrometry, and ischemia was produced by stopping flow for 15 minutes followed by 3 hours of reperfusion. Depleting leukocytes by 90 +/- 3.2% and platelets by 100% improved segmental function (from 30.5 +/- 7% to 74.1 +/- 12.7% for control versus leukocyte-depleted dogs, re...
Association of a Shortened Duration of Adjuvant Chemotherapy With Overall Survival Among Individuals With Stage III Colon Cancer
Authors: Devon J. Boyne, Winson Y. Cheung, Robert J. Hilsden, Tolulope T. Sajobi, Atul Batra, Christine M. Friedenreich, Darren R. Brenner
Journal: JAMA Network Open (2021)

<h3>Importance</h3> Several real-world oncology studies have produced findings that contradict those from randomized clinical trials. Such disparities may be associated with methodological shortcomings. <h3>Objective</h3> To examine the association between a shortened duration of adjuvant chemotherapy among individuals with stage III colon cancer using real-world data. <h3>Design, Setting, and Participants</h3> This comparative effectiveness study included individuals diagnosed with stage III colon cancer between January 2004 and December 2015 who initiated adjuvant chemotherapy at oncology clinics within the province of Alberta, Canada. Patients were identified through record linkage of various administrative databases and were followed up until September 2017. Eligibility criteria were modeled after those used in the International Duration Evaluation of Adjuvant (IDEA) trial. A target trial emulation and naive observational analysis were conducted. Results from both cohorts were benchmarked against findings from the IDEA trial. Data analysis was conducted from March to December 2020. <h3>Exposure</h3> A shortened duration of adjuvant 5-fluorouracil/leucovorin plus oxaliplatin (FOLFOX) or capecitabine plus oxaliplatin (CAPOX) chemotherapy, defined as 3 to 5 months of treatment vs 6 months. <h3>Main Outcomes and Measures</h3> Overall survival assessed via vital statistics. The per-protocol hazard ratio (HR) was estimated using a weighted pooled logistic regression model. Subgroup analyses were conducted by treatment regimen (ie, FOLFOX vs CAPOX) and cancer stage (ie, T1-3 and N1 vs T4 or N2). <h3>Results</h3> From an initial cohort of 3086 patients, 485 (16%) were eligible for inclusion in the target trial analysis. The median age was 59 years (range, 19-81 years), and 230 (47%) were women. The maximum follow-up was 11.6 years. Median overall survival was not reached. A total of 90 patients (19%) died. The 5-year Kaplan Meier overall survival estimate was 0.79 (95% CI, 0.75-0.84). Estimates from the trial emulation were similar to those from the IDEA trial. For example, a shortened duration of adjuvant chemotherapy was not associated with overall survival among patients prescribed CAPOX in the IDEA trial (HR, 0.96; 95% CI, 0.85-1.08) or in the trial emulation (HR, 0.96; 95% CI, 0.43-2.14). In contrast, the naive observational analysis suggested that a shortened duration of CAPOX was significantly associated with worse survival (HR, 3.33; 95% CI, 1.04-10.65). <h3>Conclusions and Relevance</h3> In this study, the explicit emulation of a target trial better approximated results from an analogous well-conducted randomized clinical trial.