tbuckley/cabot-search huggingface dataset:
The development of the entire end-systolic pressure-volume and ejection fraction-afterload relations: a new concept of systolic myocardial stiffness.
Authors: IMirsky, TTajimi, K LPeterson
Journal: Circulation (1987)

In this study we introduce a new concept of systolic myocardial stiffness that extends the Suga-Sagawa maximum ventricular elastance concept to the myocardium. End-systole is defined as the time of maximum systolic myocardial stiffness (max Eav), which we examined for its load independence and sensitivity to changes in the inotropic state and to heart rate. Seven adult mongrel dogs were instrumented with ultrasonic crystals for measurements of long and short axes and left ventricular wall thickness, and a high-fidelity micromanometer was inserted for measurement of left ventricular pressures. Preload and afterload were altered by inferior vena cava occlusion, nitroprusside, angiotensin II, atropine, propranolol, and various combinations with propranolol. End-systolic stress-strain relations (slope: max Eav) were linear in all seven dogs, implying that end-systolic myocardial stiffness is independent of end-systolic stress. Changes in max Eav (for constant preload and afterload) reflected changes in the ej...
Physiological substrate for antidromic reciprocating tachycardia. Prerequisite characteristics of the accessory pathway and atrioventricular conduction system.
Authors: D LPacker, J JGallagher, E NPrystowsky
Journal: Circulation (1992)

BACKGROUNDAlthough the anatomic  for the occurrence of antidromic reciprocating tachycardia (ART) has been previously examined, the underlying physiological substrate for this unusual arrhythmia in patients with the Wolff-Parkinson-White syndrome has not been thoroughly characterized.METHODS AND RESULTSThe electrophysiological properties of the accessory pathway and normal ventriculoatrial conduction system in 30 patients with ART and a single accessory pathway were compared with those observed in a control group of 36 patients without this arrhythmia to elucidate the critical physiological substrate essential for the development and maintenance of ART. Inducible ART had a mean cycle length of 286 +/- 31 msec. The average retrograde ventriculoatrial conduction system effective refractory period in ART patients was significantly less than that in the control group (244 +/- 32 versus 291 +/- 46 msec, p = 0.0002). All of the ART patients showed retrograde conduction over the normal conduction syst...
Letter by De Ferrari and Verrier Regarding Article, “Role of Microvolt T-Wave Alternans in Assessment of Arrhythmia Vulnerability Among Patients With Heart Failure and Systolic Dysfunction: Primary Results From the T-Wave Alternans Sudden Cardiac Death in Heart Failure Trial Substudy”
Authors: Gaetano M. De Ferrari, Richard L. Verrier
Journal: Circulation (2009)
Chronic nonocclusive coronary artery constriction impairs ventricular function, myocardial structure, and cardiac contractile protein enzyme activity in rats.
Authors: J MCapasso, AMalhotra, XZhang, JScheuer, PAnversa
Journal: Circulation Research (1992)

To determine the effects of chronic nonocclusive coronary constriction on cardiac hemodynamics, structural integrity, and contractile protein enzyme activity, the left coronary artery was narrowed in rats, and measurements of ventricular performance, magnitude, and distribution of tissue damage and myofibrillar Mg2+ and Ca2+ myosin ATPase activities were evaluated 1 month later. In the presence of coronary artery stenosis averaging 58%, three levels of involvement of global cardiac performance were identified, and the rats were divided accordingly. In the first group, only left ventricular end-diastolic pressure (LVEDP) was increased; in the second group, LVEDP and left ventricular +dP/dt and/or -dP/dt were affected; and in the third group, LVEDP, left ventricular +dP/dt and -dP/dt, and right ventricular end-diastolic pressure were impaired. Thus, left ventricular moderate dysfunction, severe dysfunction, and failure occurred with coronary narrowing. On a structural basis, coronary constriction resulted i...
Stimulation of hypertrophy of cultured neonatal rat heart cells through an alpha 1-adrenergic receptor and induction of beating through an alpha 1- and beta 1-adrenergic receptor interaction. Evidence for independent regulation of growth and beating.
Authors: PSimpson
Journal: Circulation Research (1985)

Catecholamines may be one of the molecular signals linking increased circulatory demand to myocardial hypertrophy, and I have found previously that norepinephrine stimulates hypertrophy of cultured neonatal rat heart muscle cells through an alpha 1-adrenergic receptor. Since catecholamine stimulation of contractility is believed to be under beta-adrenergic control, I asked whether these cultured heart cells had dual pathways regulating growth and contractility through alpha- and beta-adrenergic receptors, respectively. I examined the effect of adrenergic agents on hypertrophy and beating of myocytes in serum-free cultures. Hypertrophy was defined as an increase in myocyte surface area and in cell protein content, measured by a radioisotopic method, and chronotropic activity was examined visually. Norepinephrine and epinephrine were equipotent stimulants of hypertrophy and beating, increasing cell protein and area 1.5- to 2-fold, and the proportion of beating cells from 5% or less to 95%. Response maxima o...
Evaluation of 99mtechnetium stannous pyrophosphate as an imaging agent in acute myocardial infarction.
Authors: F PBruno, F RCobb, FRivas, J KGoodrich
Journal: Circulation (1976)

Serial 99mTc pyrophosphate scintigrams were obtained 7 hr to 15 days after experimental acute myocardial infarction produced by permanent or transient coronary occlusion. Scintigrams were interpreted visually and the increased radioactivity in the precordial image was quantitated and compared to extent of infarction found histologically. Results of these studies indicate: 1) 99mTc pyrophosphate imaging is an extremely sensitive for detection of acute myocardial infarction, i.e., infarction in excess of 1% of the left ventricular mass was detected. 2) Early detection of acute infarction is a function of blood flow since 7 hr after infarction scans were negative after permanent occlusion but were strongly positive after transient occlusion. 3) Radioactivity in the precordial image was inversely related to extent of infarction after permanent occlusion and directly related to extent of infarction after transient occlusion. 4) 99mTc pyrophosphate localized in areas with significant histologic infarction but t...
Increase of the delayed rectifier K+ and Na(+)-K+ pump currents by hypotonic solutions in guinea pig cardiac myocytes.
Authors: NSasaki, TMitsuiye, ZWang, ANoma
Journal: Circulation Research (1994)

To investigate the membrane current changes induced by membrane stretching, single guinea pig ventricular myocytes were superfused with solutions of various osmolarities, and the whole-cell current was recorded by the patch-clamp technique. The application of 70% and 130% osmolar bath solutions increased and decreased the amplitude of delayed rectifier K+ current (IK), respectively, whereas no obvious change was observed in the L-type Ca2+ current or the inward rectifier K+ current. When the Na(+)-K+ pump current (Ipump) was recorded by the use of high-Na+ (> 35 mmol/L) pipette solutions, Ipump was also increased and decreased by the superfusion of hypotonic and hypertonic solutions, respectively, in approximately half of the cells. An increase of the Ipump was also observed in the absence of external Na+, excluding a possibility that the enhancement of Ipump was secondary to an elevation of cytosolic Na+. In most cells that did not show the increase of Ipump, the hypotonic superfusion induced a gradual a...
Potentiation of the hemodynamic effects of acutely administered nitroglycerin by methionine.
Authors: W SLevy, R JKatz, R LRuffalo, R HLeiboff, A GWasserman
Journal: Circulation (1988)

It is believed that nitroglycerin causes vasodilatation by interacting with sulfhydryl groups present in vascular smooth muscle. This study was performed to assess whether methionine, an amino acid capable of increasing sulfhydryl availability, would potentiate the hemodynamic effects of nitroglycerin. Nitroglycerin was initially infused in incremental doses from 1 to 50 micrograms/min in all patients to determine the dose required to reduce mean arterial pressure by 10% and pulmonary capillary wedge pressure by 30%. After a washout period, 10 patients received 5 g methionine i.v. and five patients received an equal volume of 5% dextrose in water (control). Nitroglycerin dose titration was then repeated. Methionine alone induced no hemodynamic effects, but after methionine infusion, there was a significant reduction in the nitroglycerin infusion rate required to reach each hemodynamic endpoint (p less than 0.01). In the control group, there was no significant change in responsiveness to nitroglycerin betw...
Protective effects of N-2-mercaptopropionyl glycine against myocardial reperfusion injury after neutrophil depletion in the dog: evidence for the role of intracellular-derived free radicals.
Authors: S EMitsos, T EAskew, J CFantone, S LKunkel, G DAbrams, ASchork, B RLucchesi
Journal: Circulation (1986)

Reperfusion of the previously ischemic myocardium is associated with the production of oxygen free radicals and their metabolites, which contribute to the ultimate extent of irreversible myocardial injury. The relative importance of polymorphonuclear leukocytes vs intracellular-derived oxygen metabolites has remained uncertain. We evaluated the effectiveness of a free-radical scavenger, N-2-mercaptopropionyl glycine (MPG), in limiting infarct size after ischemia/reperfusion in dogs that were depleted of neutrophils with specific antisera. Twenty-four urethane-anesthetized open-chest dogs were subjected to 90 min of ischemia by occlusion of the left circumflex coronary artery followed by 6 hr of reperfusion. Dogs were randomly assigned to receive nonimmune serum, neutrophil antiserum, or neutrophil antiserum plus MPG (20 mg/kg intra-atrially 15 min before reperfusion was initiated and for 45 min after reperfusion). Infarct size, as a percent of the area at risk, was reduced by 33% in the neutrophil antiser...
Abstract 17173: Diastolic Blood Pressure Levels and Mortality Among Older Women: Results From the Women’s Health Initiative Long Life Study
Authors: Sylvia Wassertheil-Smoller, Aileen McGinn, Bernhard Haring, Victor Kamensky, Michael Alderman
Journal: Circulation (2019)

Background: Systolic blood pressure (SBP) targets of 120mmHg often do not take into account the impact of concomitantly lowering diastolic blood pressure (DBP) to achieve these targets, especially ...
Immune response to dermatomyositis-specific autoantigen, transcriptional intermediary factor 1γ can result in experimental myositis
Authors: Naoko Okiyama, Yuki Ichimura, Miwako Shobo, Ryota Tanaka, Noriko Kubota, Akimasa Saito, Yosuke Ishitsuka, Rei Watanabe, Yasuhiro Fujisawa, Yoshiyuki Nakamura, Akihiro Murakami, Hisako Kayama, Kiyoshi Takeda, Manabu Fujimoto
Journal: Annals of the Rheumatic Diseases (2021)

Objectives To investigate whether autoimmunity to transcriptional intermediary factor 1 (TIF1)γ, a ubiquitous nuclear autoantigen for myositis-specific autoantibodies detected in patients with dermatomyositis (DM) is pathogenetic for inflammatory myopathy. Methods Wild-type, β 2 -microglobulin-null, perforin-null, Igμ‐null and interferon α/β receptor (IFNAR)-null mice were immunised with recombinant human TIF1γ whole protein. A thymidine incorporation assay was performed using lymph node T cells from TIF1γ-immunised mice. Plasma was analysed using immunoprecipitation followed by western blot analysis and enzyme-linked immunosorbent assays. Femoral muscles were histologically and immunohistochemically evaluated. CD8 + or CD4 + T cells isolated from lymph node T cells or IgG purified from plasma were adoptively transferred to naïve mice. TIF1γ-immunised mice were treated with anti-CD8 depleting antibody and a Janus kinase inhibitor, tofacitinib. Results Immunisation with TIF1γ-induced experimental myositis presenting with necrosis/atrophy of muscle fibres accompanied by CD8 + T cell infiltration successfully in wild-type mice, in which TIF1γ-specific T cells and antihuman and murine TIF1γ IgG antibodies were detected. The incidence and severity of myositis were significantly lower in β₂-microglobulin-null, perforin-null, CD8-depleted or IFNAR-null mice, while Igμ‐null mice developed myositis normally. Adoptive transfer of CD8 + T cells induced myositis in recipients, while transfer of CD4 + T cells or IgG did not. Treatment with tofacitinib inhibited TIF1γ-induced myositis. Conclusions Here we show that TIF1γ is immunogenic enough to cause experimental myositis, in which CD8 + T cells and type I interferons, but not CD4 + T cells, B cells or antibodies, are required. This murine model would be a tool for understanding the pathologies of DM.
Incomplete filling and incoordinate contraction as mechanisms of hypotension during ventricular tachycardia in man.
Authors: J ALima, J LWeiss, P AGuzman, M LWeisfeldt, P RReid, T ATraill
Journal: Circulation (1983)

We sought to determine mechanisms for decrease of cardiac output and for hypotension during ventricular tachycardia (VT) in man. Two-dimensional and M mode echocardiograms and left ventricular pressure from micromanometer-tipped catheters were obtained in 20 patients before, during, and at the end of induced hypotensive VT. Patients were divided into two groups according to left ventricular function in sinus rhythm as assessed by angiographic ejection fraction (EF) before electrophysiologic study. Group 1 (n = 8) had angiographic EF greater than or equal to 50% in normal sinus rhythm, and group 2 (n = 12) had EF less than or equal to 40%. During VT, left ventricular cavity volume (as indexed by short- and long-axis two-dimensional end-diastolic cavity areas) was markedly reduced in group 1, from 19.7 +/- 2 to 8.6 +/- 2 cm2 (p less than .001) and from 32.0 +/- 8 to 22.5 +/- 7 cm2 (p less than .001), respectively, but was only slightly reduced in group 2, from 34.1 +/- 6 to 31.5 +/- 7 cm2 (p = .044) and fro...
Post-myocardial infarction mortality in patients with ventricular premature depolarizations. Canadian Amiodarone Myocardial Infarction Arrhythmia Trial Pilot Study.
Authors: J ACairns, S JConnolly, MGent, RRoberts
Journal: Circulation (1991)

BACKGROUNDAmong survivors of acute myocardial infarction, frequent and repetitive ventricular premature depolarizations (VPDs) detected on ambulatory monitoring contribute independently to the risk of all-cause mortality and sudden death. Apart from the beta-blockers, no antiarrhythmic drug has been reliably demonstrated to reduce mortality among patients with VPDs. A pilot study was undertaken to gather data to aid in the design of a multicenter trial of amiodarone for the reduction of mortality from cardiac arrhythmias in such patients.METHODS AND RESULTSSeventy-seven patients with acute myocardial infarction within the previous 6-30 days and 10 or more VPDs/hr or one or more runs of ventricular tachycardia on 24-hour electrocardiographic recording were randomized in a double-blind fashion in a 2:1 amiodarone-to-placebo ratio. The loading dose was 10 mg/kg/day for 3 weeks. The maintenance dose was 300-400 mg/day with reductions at 4-month intervals in response to VPD suppression, excessive plasma levels...
Hemodynamics in transgenic mice with overexpression of atrial natriuretic factor.
Authors: R WBarbee, B DPerry, R NRé, J PMurgo, L JField
Journal: Circulation Research (1994)

The circulatory effects associated with lifelong plasma atrial natriuretic factor (ANF) elevation were examined by generating transgenic mice, which constitutively express a fusion gene consisting of the transthyretin promoter and the ANF structural gene. These mice have chronically elevated ANF levels as compared with their nontransgenic siblings. Transgenic animals exhibited immunoreactive ANF levels that were nearly fivefold higher than those measured in nontransgenic littermates. Systemic and regional hemodynamics and blood volumes were explored by using modifications of the reference microsphere and dilution techniques. Mean arterial pressure was reduced by 24 mm Hg, associated with a 27% reduction in total heart weight. This chronic reduction in blood pressure was due to a 21% reduction in total peripheral resistance, whereas cardiac output, stroke volume, and heart rate were not significantly altered, despite a 15% elevation in plasma volume. Transgenic mice displayed reductions of 35%, 33%, 32%, a...
Noninvasive quantification of muscarinic receptors in vivo with positron emission tomography in the dog heart.
Authors: JDelforge, MJanier, ASyrota, CCrouzel, J MVallois, JCayla, J PLançon, B MMazoyer
Journal: Circulation (1990)

The in vivo quantification of myocardial muscarinic receptors has been obtained in six closed-chest dogs by using positron emission tomography. The dogs were injected with a trace amount of 11C-labeled methylquinuclidinyl benzilate (MQNB), a nonmetabolized antagonist of the muscarinic receptor. This was followed 30 minutes later by an injection of an excess of unlabeled MQNB (displacement experiment). Two additional injections of unlabeled MQNB with [11C]MQNB (coinjection experiment) and without [11C]MQNB (second displacement experiment) were administered after 70 and 120 minutes, respectively. This protocol allowed a separate evaluation of the quantity of available receptors (B'max) as well as the association and dissociation rate constants (k+1 and k-1) in each dog. The parameters were calculated by using a nonlinear mathematical model in regions of interest over the left ventricle and the interventricular septum. The average value of B'max was 42 +/- 11 pmol/ml tissue, the rate constants k+1, k-1, and ...
Characteristics and possible mechanism of ventricular arrhythmia dependent on the dispersion of action potential durations.
Authors: C SKuo, KMunakata, C PReddy, BSurawicz
Journal: Circulation (1983)

The arrhythmogenic role of increased dispersion of repolarization (dispersion) was studied in 23 open-chest dogs using six simultaneously recorded monophasic action potentials (MAPs) from the ventricular surface and programmed ventricular premature stimulation (VPS). Increased dispersion was induced by generalized hypothermia (29 degrees C) and regional warm blood (38-43 degrees C) perfusion through a coronary artery branch. Hypothermia and regional warm blood perfusion increased maximum dispersion from 13 +/- 10 to 111 +/- 16 msec (p less than 0.001), predominantly because of the increased MAP duration difference (10 +/- 15 vs 97 +/- 16 msec, p less than 0.001). The maximal difference between activation times was not significantly changed, but the QRS duration increased from 47 +/- 6 to 52 +/- 7 msec (p less than 0.01). Ventricular arrhythmia did not occur spontaneously but was induced by a single VPS in all 23 dogs during hypothermia and regional warm blood perfusion when dispersion reached a critical m...
Assessment of left ventricular pressure-volume relations using gated radionuclide angiography, echocardiography, and micromanometer pressure recordings. A new method for serial measurements of systolic and diastolic function in man.
Authors: D JMagorien, PShaffer, C ABush, R DMagorien, A JKolibash, C VLeier, T MBashore
Journal: Circulation (1983)

This study was designed to validate the use of combined invasive and noninvasive methods in assessing serial pressure-volume relations in man. Ten patients undergoing cardiac catheterization were studied with simultaneous intracardiac micromanometer pressure recordings, gated radionuclide angiography and echocardiography. Systolic and diastolic function were measured at rest, during right atrial pacing rates of 100 and 120 beats/min and after nitroglycerin administration. Right atrial pacing studies (rate of 100 beats/min) were performed in duplicate to determine the reproducibility of the method. At the conclusion of each study, the model was validated with contrast angiography. Good reproducibility was evident when measuring the maximum and average filling and ejection rates, time to peak filling rate, ejection fraction, the modulus of chamber stiffness, the time course of left ventricular relaxation, global average stress and ventricular work indexes using the model described above. These data were not...
Endoscopic Features and Mucosal Patterns Associated With Collagenous Colitis
Authors: O Labianca, M Sica, C Zulli, A Maurano
Journal: Endoscopy (2021)

Aims Collagenous colitis (CC) is a morphological and clinical-pathological entity of microscopic colitis, characterized by secretory-like aqueous chronic diarrhea, mostly without hematochezia. Although there are no mucosal abnormalities, in some cases particular endoscopic features and mucosal patterns may be described. We have evaluated the endoscopic findings in patients diagnosed with CC in our Digestive Endoscopy Unit.
Microarray patches: Breaking down the barriers to contraceptive care and HIV prevention for women across the globe
Authors: Alejandro J. Paredes, Inken K. Ramöller, Peter E. McKenna, Marco T.A. Abbate, Fabiana Volpe-Zanutto, Lalitkumar K. Vora, Maggie Kilbourne-Brook, Courtney Jarrahian, Kurtis Moffatt, Chunyang Zhang, Ismaiel A. Tekko, Ryan F. Donnelly
Journal: Advanced Drug Delivery Reviews (2021)
Mechanism of endothelin-1-induced pulmonary vasoconstriction.
Authors: M JHorgan, J MPinheiro, A BMalik
Journal: Circulation Research (1991)

Endothelins are endothelial cell-derived peptides with potent vasoconstrictor properties. We investigated the actions of porcine/human endothelin-1 (ET-1) on the microvasculature of the guinea pig lung perfused at constant flow with Ringers-albumin. We measured the perfusion pressure, distribution of pulmonary vascular resistance (using the double occlusion method), lung weight change, and the pulmonary capillary filtration coefficient. At concentrations of greater than or equal to 10(-10) M, ET-1 produced dose-dependent increases in mean pulmonary artery pressure (EC50, approximately 10(-9.5) M), which were rapid in onset and biphasic (first phase peaking at 1-2 minutes; second phase peaking at 10-15 minutes) up to 60 minutes of the perfusion period. The vasoconstrictor response was sustained for the 60-minute perfusion period. The pulmonary vasoconstriction was inhibited by pretreatment with indomethacin (10(-5) M), the thromboxane A2 receptor antagonist SQ-29,548 (4 x 10(-6) M), or papaverine (10(-5) M...
Hydrodynamic compression of the right atrium: a new echocardiographic sign of cardiac tamponade.
Authors: L DGillam, D EGuyer, T CGibson, M EKing, J EMarshall, A EWeyman
Journal: Circulation (1983)

The relationship of right atrial inversion, a previously undescribed cross-sectional echocardiographic sign, to the presence of cardiac tamponade was examined. We studied 127 patients with moderate or large pericardial effusions. Cardiac tamponade was present in 19 and absent in 104. Four patients with equivocal tamponade were excluded from analysis. Right atrial inversion was present in 19 of 19 patients with cardiac tamponade and 19 of 104 without cardiac tamponade (sensitivity, 100%; specificity, 82%; predictive value, 50%). The degree of inversion as quantitated by the area-corrected curvature did not improve the ability to discriminate between patients with and without cardiac tamponade. However, consideration of the duration of inversion by the right atrial inversion time index (duration of inversion/cardiac cycle length) and an empirically derived cut-off of 0.34 did improve the specificity and predictive value (100% and 100%, respectively) without a significant loss of sensitivity (94%). We conclu...