tbuckley/cabot-search huggingface dataset:
Role of afterload in determining regional right ventricular performance during coronary underperfusion in dogs.
Authors: YUrabe, HTomoike, KOhzono, SKoyanagi, MNakamura
Journal: Circulation Research (1985)

The relationship between coronary perfusion pressure and regional myocardial performance of the right ventricular free wall was studied, in the presence or absence of right ventricular hypertension in 13 open-chest dogs. The right coronary artery was perfused through a shunt from a carotid artery. Regional systolic shortening of the right ventricular free wall was measured by means of a sonomicrometric technique at various levels of coronary perfusion pressure. Regional shortening was insensitive to coronary perfusion pressure or flow when it was above 31 mm Hg or 0.27 ml/min per g. Once coronary perfusion was below this critical level, regional shortening in both base to apex and circumferential orientations decreased linearly, depending on the degree of perfusion pressure. Despite the presence of a monoexponential relationship between coronary perfusion pressure or flow and regional shortening, a direct linear relation between perfusion pressure and flow was consistently noted, with or without pulmonary...
The effects of membrane potential, extracellular potassium, and tetrodotoxin on the intracellular sodium ion activity of sheep cardiac muscle.
Authors: C TJanuary, H AFozzard
Journal: Circulation Research (1984)

The intracellular sodium ion activity was measured using liquid ion-exchange microelectrodes with rapid response times in sheep Purkinje fibers and ventricular muscle under voltage control. The mean sodium ion activity in quiescent Purkinje fibers was 8.5 mM at a holding potential of -80 mV. With maintained hyperpolarizing (-110 mV) or depolarizing (-40 and 0 mV) voltage steps, sodium ion activity increased or decreased, respectively. At 0 mV, the mean steady state value for the sodium ion activity was 3.8 mM. Following a voltage step to 0 mV, or back to -80 mV, the time course of the sodium ion activity change could be fitted by single exponentials, with similar half-times. Increasing the extracellular potassium ion concentration from 5.4 to 15 mM did not alter the steady state value of the sodium ion activity at clamped voltages of -80 or 0 mV, which suggests that the external potassium ion activating site of the Na-K pump was saturated. With the extracellular potassium concentration 0 mM (holding poten...
TCTAP A-046 Incidence of Silent Ischemic Stroke After Transcatheter Aortic Valve Replacement in Severe Aortic Stenosis in Thailand Using 3.0 Tesla MRI
Authors: Numfon Sinchai, Wongsakorn Luangphiphat, Chatree Wongsinkongman, Viroj Muangsillapasart, Anuruck Jeamanukoolkit, Piyanart Preeyanont, Worawut Tassanawiwat, Jiraporn Laothamatas, Tanyarat Aramsareewong
Journal: Journal of the American College of Cardiology (2021)
Carbon Monoxide Poisoning
Authors: Arthur J. McBay
Journal: New England Journal of Medicine (1965)

MEDICOLEGAL problems arise when carbon monoxide is responsible for death. The cause of death may be conclusively established if the amount of carbon monoxide in the blood is determined, and if this amount exceeds certain limits. Once death has been discovered to be due to carbon monoxide, establishing whether it is accidental, suicidal or homicidal is often very difficult. The source of the carbon monoxide must be ascertained by competent investigators, not only to document the specific cause of death but, even more important, to cause the condition to be remedied to prevent further casualties from the same source. Every . . .
The True False Negative Rate of Colon Capsule Endoscopy is Low
Authors: S Semenov, Ismail MS, F O’Hara, S O’Donnell, A O’Connor, N Breslin, B Ryan, D McNamara
Journal: Endoscopy (2021)

Aims Colon capsule endoscopy (CCE) is an established diagnostic tool for colonic pathology. There is a lack of clinical data on the true capsule false negative (FN) rates. We aimed to assess the causes of missed pathology in a CCE cohort.
Sarcomere length-resting tension relation in single frog atrial cardiac cells.
Authors: MTarr, J WTrank, PLeiffer, NShepherd
Journal: Circulation Research (1979)

It generally has been thought that the relatively high resting tension characteristic of cardiac tissue resides in structures (collagen, elastin) external to the individual cardiac cells, but the evidence to support this conclusion has been indirect, since the resting tension of intact single cardiac cells has not been determined previously. The purpose of the present investigation was to determine the resting tension (stress)-sarcomere length relationships of single intact frog atrial cells. For tension determinations, a single cell was attached between two poly-L-lysine coated glass beams; one beam served as a compliant calibrated cantilevered force beam, and length changes were imposed on the cell by movement of the other beam. Coventional bright-field light microscope techniques were used to view the cell, the sarcomere pattern within the cell, and the position of the force beam. The resting tension of the intact cell increased from a value of about 10 nN at a sarcomere length of 2.35 microns to a val...
Noninvasive visualization of the left main coronary artery by cross-sectional echocardiography.
Authors: A EWeyman, HFeigenbaum, J CDillon, K WJohnston, R CEggleton
Journal: Circulation (1976)

Real time cross-sectional echocardiographic studies of the left main coronary artery (LMCA) were performed in 15 normal patients, 15 patients with angiographically proven coronary artery disease but normal left main coronary segments, three patients with greater than 75% obstruction of the left main coronary artery, and one patient with a larger aneurysm of the left main coronary artery. In normal subjects the LMCA evaginates from in inferolateral wall of the aorta. The artery appears as two dominant parallel linear echoes separated by a clear space representing the lumen of the vessel. The LMCA courses beneath the right ventricular outflow tract and can generally be followed to its expected point of bifurcation. Confirmation that this structure was in fact the LMCA was obtained by injection of cardiogreen dye directly into the LMCA in two cases and by visualization of dye in this structure following aortic flush in one case. In the three cases with obstructive lesions of the LMCA, there was an area of in...
Phenotypic characterization of leukemia-initiating stem cells in chronic myelomonocytic leukemia
Authors: Gregor Eisenwort, Irina Sadovnik, Alexandra Keller, Daniel Ivanov, Barbara Peter, Daniela Berger, Gabriele Stefanzl, Karin Bauer, Katharina Slavnitsch, Georg Greiner, Karoline V. Gleixner, Wolfgang R. Sperr, Michael Willmann, Heinz Sill, Peter Bettelheim, Klaus Geissler, Michael Deininger, Thomas Rülicke, Peter Valent
Journal: Leukemia (2021)
Super-Resolution of Cardiac MR Cine Imaging using Conditional GANs and Unsupervised Transfer Learning
Authors: Yan Xia, Nishant Ravikumar, John P. Greenwood, Stefan Neubauer, Steffen E. Petersen, Alejandro F. Frangi
Journal: Medical Image Analysis (2021)

High-resolution (HR), isotropic cardiac Magnetic Resonance (MR) cine imaging is challenging since it requires long acquisition and patient breath-hold times. Instead, 2D balanced steady-state free precession (SSFP) sequence is widely used in clinical routine. However, it produces highly-anisotropic image stacks, with large through-plane spacing that can hinder subsequent image analysis. To resolve this, we propose a novel, robust adversarial learning super-resolution (SR) algorithm based on conditional generative adversarial nets (GANs), that incorporates a state-of-the-art optical flow component to generate an auxiliary image to guide image synthesis. The approach is designed for real-world clinical scenarios and requires neither multiple low-resolution (LR) scans with multiple views, nor the corresponding HR scans, and is trained in an end-to-end unsupervised transfer learning fashion. The designed framework effectively incorporates visual properties and relevant structures of input images and can synthesise 3D isotropic, anatomically plausible cardiac MR images, consistent with the acquired slices. Experimental results show that the proposed SR method outperforms several state-of-the-art methods both qualitatively and quantitatively. We show that subsequent image analyses including ventricle segmentation, cardiac quantification, and non-rigid registration can benefit from the super-resolved, isotropic cardiac MR images, to produce more accurate quantitative results, without increasing the acquisition time. The average Dice similarity coefficient (DSC) for the left ventricular (LV) cavity and myocardium are 0.95 and 0.81, respectively, between real and synthesised slice segmentation. For non-rigid registration and motion tracking through the cardiac cycle, the proposed method improves the average DSC from 0.75 to 0.86, compared to the original resolution images.
Integrative microbiomics in bronchiectasis exacerbations
Authors: Micheál Mac Aogáin, Jayanth Kumar Narayana, Pei Yee Tiew, Nur A’tikah Binte Mohamed Ali, Valerie Fei Lee Yong, Tavleen Kaur Jaggi, Albert Yick Hou Lim, Holly R. Keir, Alison J. Dicker, Kai Xian Thng, Akina Tsang, Fransiskus Xaverius Ivan, Mau Ern Poh, Martina Oriano, Stefano Aliberti, Francesco Blasi, Teck Boon Low, Thun How Ong, Brian Oliver, Yan Hui Giam, Augustine Tee, Mariko Siyue Koh, John Arputhan Abisheganaden, Krasimira Tsaneva-Atanasova, James D. Chalmers, Sanjay H. Chotirmall
Journal: Nature Medicine (2021)
The mechanism of termination of reentrant activity in ventricular fibrillation.
Authors: Y MCha, UBirgersdotter-Green, P LWolf, B BPeters, P SChen
Journal: Circulation Research (1994)

The reentrant wave fronts in ventricular fibrillation (VF) have only a limited life span. The mechanisms by which these reentrant wave fronts terminate are unknown. We performed computerized mapping studies in six open-chest dogs before and after right ventricular subendocardial ablation with Lugol's solution. Recordings were made with 56 bipolar electrodes separated by 3 mm. Baseline pacing was performed on the right side of the tissue to create parallel activation wave fronts. A premature 50-V shock of either anodal or cathodal polarity was given to a bar electrode on the upper edge of the tissue. Counterclockwise reentrant wave fronts and VF were induced both before (60 episodes) and after (57 episodes) subendocardial ablation with either anodal or cathodal shocks. Among these reentrant wave fronts, 8 episodes before and 10 episodes after ablation had over 10 rotations (P = NS). The reentrant wave fronts in other episodes terminated with an average of 3.2 +/- 1.9 rotations before and 3.1 +/- 1.8 rotati...
Management of Hyperglycemia in Type 2 Diabetes: A Consensus Algorithm for the Initiation and Adjustment of Therapy: A Consensus Statement From the American Diabetes Association and the European Association for the Study of Diabetes
Authors: Christopher G. Parkin, Jaime A. Davidson
Journal: Diabetes Care (2006)

We applaud the efforts of those who developed the American Diabetes Association/European Association for the Study of Diabetes algorithm for managing type 2 diabetes (1). Although the algorithm provides a comprehensive assessment of the clinical utility of various medications, the authors’ strong focus on A1C as a measure of glycemic control may lead to inadequate management of glycemia because it fails to consider important issues relevant to diabetes pathophysiology and outcomes.

First, the algorithm assumes that patients have only recently developed type 2 diabetes and that the A1C is only slightly elevated. The majority of type 2 diabetes is diagnosed 9–12 years after it develops (2). Further, the algorithm suggests that individuals should first be …
Morphometry of exercise-induced right ventricular hypertrophy in the rat.
Authors: PAnversa, VLevicky, CBeghi, S LMcDonald, YKikkawa
Journal: Circulation Research (1983)

In our morphometric study of the effects of exercise on the heart, male Wistar-Kyoto rats at 5 weeks of age were subjected daily to a moderate treadmill running program that lasted for 7 weeks. The heart responded to physical conditioning by different magnitudes of tissue growth of the right (22%) and left (7%) ventricular myocardium, the latter change not statistically significant. The increase in right ventricular volume was associated with a 25% enlargement of ventricular area, a 26% average lengthening of the myocytes, and no change in sarcomere length and in ventricular midwall thickness. Exercise produced significant alterations in the quantitative parameters of the microvasculature of the right ventricle, but no appreciable changes in the left ventricle. Right ventricular hypertrophy was characterized by an absolute 44% growth of the endothelial luminal surface brought about through a 16% increase in capillary numerical density, and a 41% augmentation of the total length of the capillary network. M...
Spinal adrenergic mechanisms regulating sympathetic outflow to blood vessels.
Authors: D GTaylor, M JBrody
Journal: Circulation Research (1976)

The role of descending spinal catecholamine (CA)-containing fibers in cardiovascular regulation was examined. Monoamine-containing fibers were visualized by fluorescence histochemical methods at the cervical, thoracic, and lumbar spinal segments. Two major groups of descending CA-containing axons were located in the lateral funiculus at the midcervical spinal level. At the thoracolumbar spinal segments CA-containing terminals were concentrated mostly around cells of the intermediolateral nucleus. In addition a distinct CA-containing fasciculus was observed at the level of the sympathetic nucleus which appeared to course toward the opposite site of the cord. To evaluate the role of the efferent CA-containing fibers, changes in heart rate, arterial pressure, femoral blood flow, and calculated peak vascular resistance were elicited by electrical stimulation of selected sites in the midcervical spinal cord. Although changes in femoral flow and arterial pressure were evoked from many midcervical sites, there w...
Developmentally timed expression of an embryonic growth phenotype in vascular smooth muscle cells.
Authors: C LCook, M CWeiser, P ESchwartz, C LJones, R AMajack
Journal: Circulation Research (1994)

Little is known about the phenotypic changes that occur in vascular smooth muscle cells (SMCs) as the developing aorta undergoes the transition from a loosely organized, highly replicative tissue to a morphologically mature, quiescent tissue. In the present study, we have characterized the in vivo pattern of SMC replication during intrauterine and neonatal aortic development in the rat and have cultured and assessed the in vitro growth properties of embryonic, fetal, and neonatal vascular SMCs. Embryonic SMCs, which exhibited a very high in vivo replication rate (75% to 80% per day), demonstrated a significant potential for self-driven replication, as assessed by the ability to proliferate under serum-deprived conditions. Several lines of evidence suggest that the autonomous growth of SMCs in the  growth phenotype may be driven by a unique mechanism independent of known adult SMC mitogens: embryonic SMC replication was not associated with the detectable secretion of mitogenic activity capable o...
Diffusional shunting in the canine myocardium.
Authors: A CRoth, E OFeigl
Journal: Circulation Research (1981)

A test for the existence of a diffusional shunt in the myocardium was performed in closed-chest, chloralose-anesthetized dogs. Coronary blood flow was varied from 0.21 to 1.17 ml/min per g with a roller pump via a stainless steel coronary perfusion cannula. Following intracoronary artery bolus indicator injection, the coronary sinus venous appearance times of hydrogen, plasma protein labeled with indocyanine green dye, and red blood cells labeled with 99mTc were measured. Venous appearance time was calculated, either as the time from injection until the indicator reached 5% of its peak venous concentration or the time from injection until 0.1% of the injected material arrived at the coronary sinus. At low coronary flow rates (0.4 sec dye appearance time) hydrogen appearance preceded by about 1 second the appearance of the intravascular 99mTc-labeled red blood cells and the dyed plasma, indicating that hydrogen traversed an extravascular shunt path from small arteries to veins. As flow was increased, this ...
Identification of alpha 1-adrenergic receptors on sarcolemma from normal subjects and patients with idiopathic dilated cardiomyopathy: characteristics and linkage to GTP-binding protein.
Authors: TVago, MBevilacqua, GNorbiato, GBaldi, EChebat, PBertora, GBaroldi, RAccinni
Journal: Circulation Research (1989)

Discontinuous density sucrose gradient centrifugation was used to isolate membrane vesicles from the left ventricle of three normal subjects (one prospective organ donor and two traffic victims whose hearts were obtained 1 hour after death) and nine patients undergoing cardiac transplantation as a consequence of idiopathic dilated cardiomyopathy. Sarcolemma-enriched subcellular fractions, detected in the interface between 8.55% and 25% sucrose, were identified by the increased activity of Na+,K+-ATPase and by enrichment in beta-adrenergic receptor density. The density of beta-adrenergic receptors was lower in vesicles from diseased hearts (610 +/- 71 fmol/mg protein) than in vesicles from normal hearts (1,410 +/- 226 fmol/mg protein; p less than 0.01). alpha 1-Adrenergic receptors were identified in these membrane vesicles by [3H]prazosin binding. Specific binding of [3H]prazosin was about 50% of the total binding at 1 nM, and alpha 1-adrenergic binding sites were saturable at approximately 3 nM. Scatchar...
The effects of large negative intrathoracic pressure on left ventricular function in patients with coronary artery disease.
Authors: S MScharf, J ABianco, D ETow, RBrown
Journal: Circulation (1981)

Using first-pass radionuclide ventriculography, we evaluated the effects of decreases in intrathoracic pressure (Mueller maneuver [M] to -20 to -30 cm H2O) in 14 patients with five patients without coronary artery disease (CAD) and in 12 normal control subjects. In the patients with CAD, control ejection fraction was 0.53 +/- 0.06 (SEM) and control heart rate was 83 +/- 6 beats/min. These did not change during M. In the patients with CAD, control ejection fraction was 0.37 +/- 0.03 and heart rate was 82 +/- 7 beats/min. During M, heart rate did not change, but ejection fraction decreased to 0.33 +/- 0.33 (p less than 0.01). Examination of regional wall motion abnormalities showed akinesis of at least one myocardial segment in nine of 14 patients with CAD, but in none of the patients without CAD, nor in any of the 12 previously studied normal subjects (retrospectively analyzed). These data are consistent with the hypothesis that the Mueller maneuver acts to increase afterload placed on the left ventricle. ...
Rate-dependent changes in excitability of depressed cardiac Purkinje fibers as a mechanism of intermittent bundle branch block.
Authors: JJalife, CAntzelevitch, VLamanna, G KMoe
Journal: Circulation (1983)

When the heart rate is accelerated, rate-dependent intraventricular block may occur. This block has been attributed to abnormal action potential prolongation in a diseased conducting pathway. Less often, intraventricular block develops during slowing of the heart rate and has been explained in terms of phase 4 depolarization in potentially automatic cells within the diseased fascicle. We tested these hypotheses in isolated bundles of Purkinje fibers placed in a three-chambered tissue bath. In one group of experiments, conditions of localized injury and depressed excitability were mimicked by superfusing the central segment with sucrose solution. Action potentials were initiated in the proximal segment while the slope of phase 4 of cells in the distal end was controlled by intracellular ramps of current of either polarity. In these preparations, phase 4 depolarization facilitated rather than retarded propagation across the depressed segment, even at takeoff potentials as low as -45 mV. In a second group, d...
L-arginine augments endothelium-dependent vasodilation in cholesterol-fed rabbits.
Authors: X JGirerd, A THirsch, J PCooke, V JDzau, M ACreager
Journal: Circulation Research (1990)

Evidence exists that an endothelium-derived relaxing factor is nitric oxide and that L-arginine is the precursor for the synthesis of nitric oxide in vitro. Whether exogenous L-arginine contributes to the modulation of vascular smooth muscle tone in vivo is still controversial. In hypercholesterolemia, resistance vessels do not relax normally in response to pharmacological stimuli that release endothelium-derived relaxing factor; bioassay experiments have suggested that impaired synthesis or release of endothelium-derived relaxing factor accounts, in part, for this blunted relaxation. We hypothesized that hypercholesterolemia reduces arginine metabolism and thereby impairs endothelium-derived relaxing factor synthesis. Accordingly, we designed a study to determine whether exogenous L-arginine could augment endothelium-dependent vasodilation of hind limb resistance vessels in anesthetized cholesterol-fed rabbits. Femoral blood flow was recorded with an electromagnetic flow probe in 16 cholesterol-fed and 1...
Effects of simulated ischemia and reperfusion on the sarcoplasmic reticulum of digitonin-lysed cardiomyocytes.
Authors: C MHohl, A AGarleb, R AAltschuld
Journal: Circulation Research (1992)

ATP-dependent, inorganic phosphate-supported 45Ca2+ uptake by digitonin-lysed adult rat ventricular cardiomyocytes was used to evaluate the effects of simulated ischemia and reperfusion on the physically intact sarcoplasmic reticulum. Mitochondrial reactions were inhibited with rotenone and oligomycin. 45Ca2+ accumulation in the presence of the calcium efflux inhibitors, procaine (10 mM) and ruthenium red (30 microM), was used to characterize unidirectional uptake kinetics. A decrease in pH from 7.2 to 6.6 increased the [Ca2+] K0.5 from 0.5 to 2.0 microM and reduced the apparent Vmax by 28%. In the absence of procaine and ruthenium red, at a free [Mg2+] of 0.5 mM, maximum net uptake occurred at pCa 6.2 when pH was 7.2 and at pCa 6.0 when pH was 6.6. At lower pCa, net Ca2+ accumulation declined. Increasing free [Mg2+] from 0.5 to 1 mM at pH 6.6 or to 2.5 mM at pH 7.2 increased net 45Ca2+ accumulation in the absence of procaine and ruthenium and shifted maximum uptake to pCa 5.6 and 6.0, respectively. Incre...
Carcinoid heart disease: diagnosis by two-dimensional echocardiography.
Authors: R JHoward, MDrobac, W DRider, T JKeane, JFinlayson, M DSilver, E DWigle, HRakowski
Journal: Circulation (1982)

We prospectively studied 14 patients with the carcinoid syndrome to determine if two-dimensional echocardiography could detect the nature and extent of valvular abnormalities. Eight of the 14 patients had definite abnormalities of the right-sided cardiac valves. The tricuspid valve had a characteristic appearance, similar to previously described pathologic findings. The leaflets appeared diffusely thickened, shortened and stiff without evidence of commissural fusion. Saline contrast studies demonstrated tricuspid regurgitation, which corresponded to the severity of the tricuspid valve involvement. The pulmonary valve could only be adequately assessed in seven of 14 patients, and morphologic abnormalities similar to those in the tricuspid valve were found. Follow-up studies have shown progression of cardiac disease in six of eight patients. We conclude that two-dimensional echocardiography can detect the characteristic cardiac abnormalities in the carcinoid syndrome and may be a useful tool for following t...