tbuckley/cabot-search huggingface dataset:
Properties of oscillatory afterpotentials in young embryonic chick hearts.
Authors: MKojima, NSperelakis
Journal: Circulation Research (1984)

Oscillatory afterpotentials in cardiac tissues are believed to result from an activation of calcium-operated cation channels of mixed selectivity (sodium, potassium), or perturbation of an electrogenic sodium-calcium exchange carrier, by an oscillatory release of calcium from sarcoplasmic reticulum. In the present experiments, the presence and properties of ouabain-induced oscillatory afterpotentials were examined in young (3-day-old) embryonic chick hearts, both fresh and organ cultured for 6-14 days. The hearts did not differentiate in organ culture, and the cells retained slowly rising spontaneous action potentials. To induce the oscillatory afterpotentials, automaticity was suppressed by elevating extracellular K+ ion concentration from 4 mM to 6 mM, and the preparations were electrically stimulated at a rate of 0.5 Hz. Stable oscillatory afterpotentials were induced with 1.3-7.5 microM ouabain. The oscillatory afterpotential amplitude was increased when the stimulation rate was increased to 3 and 4 H...
Abstract 6170: Tricuspid Annular Plane Systolic Excursion Predicts Invasive Hemodynamic Markers of Right Ventricular Function in Pulmonary Hypertension
Authors: Christopher T Sibley, Lynn M Brown, Hunter C Champion, Danielle Boyce, Noah Lechtzin, Elizabeth Ketner, Joao Lima, Paul M Hassoun
Journal: Circulation (2008)

Right ventricular (RV) systolic function is an important prognostic factor in pulmonary hypertension. Its echocardiographic assessment is limited by RV geometry and poor endocardial definition. Tricuspid annular plane systolic excursion (TAPSE) and RV fractional area change (RVFAC) are used as echo measures of RV systolic function. We tested the hypothesis that TAPSE and RVFAC correlate with invasive measurements of cardiac index, dP/dt  max  and dP/dt  max  normalized to instantaneous pressure. (dP/dt max /IP). 15 consecutive patients with pulmonary hypertension and clinical indication for right heart catheterization were prospectively evaluated using high fidelity micromanometry in addition to traditional PA catheterization. Patients underwent transthoracic echo immediately following catheterization. TAPSE was measured by M-mode echo as the mean displacement (cm) of the tricuspid annular plane towards the RV apex from end diastole to end systole. RVFAC was measured as the percent change in RV area from end diastole to end systole as measured in the apical four chamber view. In this cohort, TAPSE correlates with cardiac index p≪26>0.046) and inversely with mean pulmonary artery pressure (p = 0.001). The strongest correlation was with dP/dt max /IP (r = 0.79; p max /IP. RVFAC was not of use in evaluating RV systolic function. As pulmonary hypertension generates high afterload for the RV, correlation with load-independent indices is a particularly desirable characteristic and more directly reflects myocyte contractility. TAPSE is an excellent marker of right ventricular function.
Acute myocardial infarction in toxic cardiomyopathy without coronary obstruction.
Authors: T JRegan, C FWu, A BWeisse, C BMoschos, S SAhmed, M MLyons
Journal: Circulation (1975)

Confluent left ventricular scar without significant coronary obstruction has been found in alcoholic subjects at autopsy. To evaluate the pathogenesis, 12 patients with chronic alcoholism and severe precordial pain persisting 4-24 hours were observed clinically. Cardiac isoenzymes of lactic dehydrogenase rose in serum. ST segment was elevated in anterior or posterior ECG leads, and abnormal Q waves appeared. Hypertnesion and hypercholesterolemia were present in two (group B) but not in the ten (group A). The latter exhibited no significant obstructive disease, based on coronary angiography in seven survivors and postmortem examination of the remaining three. Clinical evidence, as well as the quantitative assessment of platelets, made arterial thromboembolism an unlikely cause for the symptoms. Neither hemotologic or systemic disease affecting myocardium was present. The morphology of the left ventricle in three autopsies was compared with that of patients with alcoholism who had no cardiac disease, cardio...
Myocardial ultrastructure and the development of atrioventricular block in Kearns-Sayre syndrome.
Authors: RCharles, SHolt, J MKay, E JEpstein, J RRees
Journal: Circulation (1981)

A right ventricular endomyocardial biopsy specimen from a 30-year-old male with chromic progressive external ophthalmoplegia, retinal pigmentation and complete atrioventricular block (Kearns-Sayre syndrome) was examined in the electron microscope. There was a proliferation of mitochondria between the myofibrils and beneath the sarcolemma. Many of the mitochondria showed morphologic abnormalities not previously described in this condition. There were associated accumulations of glycogen. A similarly affected female with left anterior hemiblock developed complete atrioventricular block at age 26 years, Despite the ultrastructural changes, clinically detectable myocardial disease is not a feature of Kearns-Sayre syndrome. However, intraventricular conduction defects show an unusually rapid progression to potentially fatal complete atrioventricular block and are an indication for prophylactic cardiac pacing.
Superoxide dismutase reduces reperfusion arrhythmias but fails to salvage regional function or myocardium at risk in conscious dogs.
Authors: JNejima, D RKnight, J TFallon, NUemura, W TManders, D RCanfield, M VCohen, S FVatner
Journal: Circulation (1989)

To determine if oxygen free radical scavengers administered before coronary artery reperfusion can limit reperfusion arrhythmias, increase the return of regional function in ischemic myocardium, and reduce tissue necrosis at 1 week after 90-minute coronary artery occlusion and reperfusion, conscious dogs were treated with superoxide dismutase (SOD) and catalase before and for 1 hour after coronary artery reperfusion. Another group was treated with recombinant SOD (rSOD) because the commercially available SOD and catalase contained endotoxin. The conscious dogs were studied 3-4 weeks after implanting left ventricular pressure gauges, ultrasonic wall thickness gauges in the posterior left ventricular wall, left atrial catheters, and arterial catheters, Doppler flow transducers, and hydraulic occluders on the left circumflex coronary artery. The only beneficial effect observed was that the number of arrhythmic beats per minute in the rSOD-treated group was significantly lower (p less than 0.05) when compared...
Protein kinase C and calcium channel activation as determinants of renal vasoconstriction by angiotensin II and endothelin.
Authors: TTakenaka, HForster, MEpstein
Journal: Circulation Research (1993)

The mechanisms mediating renal microvascular constriction induced by angiotensin II (Ang II) and endothelin (ET) have not been fully established. In the present study, we have determined the effects of isradipine, a dihydropyridine calcium antagonist, on Ang II- or ET-induced constriction of afferent arterioles (AAs) and efferent arterioles (EAs) using the isolated perfused hydronephrotic kidney. Ang II (0.3 nmol/L) and ET (0.3 nmol/L) constricted AAs by 36 +/- 2% and 29 +/- 3%, respectively. Isradipine reversed AA constriction induced by both peptides. However, Ang II-induced AA constriction was more sensitive to isradipine than ET-induced constriction (half-maximal inhibitory concentration [IC50], 1.2 +/- 0.2 nmol/L [n = 12] versus 170 +/- 65 nmol/L [n = 19]; P < .01). The sensitivity of Ang II-induced AA constriction to isradipine was identical to that of KCI-induced AA constriction (IC50, 4.2 +/- 0.9 nmol/L; n = 12). Pretreatment with staurosporine (50 nmol/L), a protein kinase C inhibitor, enhanced t...
Postoperative Chemoradiotherapy or Surgery Alone for Gastric Cancer : The Plausibility of the Question and Pertinence of the Answer Reply
Authors: J.L. Dikken, E.P.M. Jansen, A. Cats, B. Bakker, H.H. Hartgrink, E.M.K. Kranenbarg, H. Boot, H. Putter, K.C.M.J. Peeters, C.J.H. van de Velde, M. Verheij
Journal: Journal of Clinical Oncology (2010)
Cardiorespiratory responses to exercise training after orthotopic cardiac transplantation.
Authors: TKavanagh, M HYacoub, D JMertens, JKennedy, R BCampbell, PSawyer
Journal: Circulation (1988)

We have tested the feasibility and effectiveness of a 2 year (average 16 +/- 7 months) walk/jog exercise program on 36 male orthotopic cardiac transplant patients (21 to 57 years old) seen initially 2 to 23 months after surgery. Comparison of initial exercise test results with those in 45 age-matched normal men showed the patients to have a lesser lean body mass (56 +/- 7 vs 63 +/- 8 kg, p less than .001), with a higher resting heart rate (104 +/- 12 vs 77 +/- 14 beats/min, p less than .001) and systolic (138 +/- 16 vs 129 +/- 17 mm Hg, p less than .001) and diastolic (95 +/- 14 vs 84 +/- 10 mm Hg, p less than .001) blood pressures. Peak power output was less than normal (101 +/- 27 vs 219 +/- 41 W, p less than .001), as was peak heart rate (136 +/- 15 vs 176 +/- 13 beats/min, p less than .001), peak oxygen intake (VO2max) (22 +/- 5 vs 34 +/- 6 ml.kg.min-1, p less than .001), and absolute anaerobic threshold (1.18 +/- 0.40 vs 2.04 +/- 0.40 liters.min-1, p less than .001). Peak ventilatory equivalent was h...
Shear stress-induced reorganization of the surface topography of living endothelial cells imaged by atomic force microscopy.
Authors: K ABarbee, P FDavies, RLal
Journal: Circulation Research (1994)

We report the first topographical data of the surface of living endothelial cells at sub-light-microscopic resolution, measurements essential for a detailed understanding of force distribution in the endothelium subjected to flow. Atomic force microscopy was used to observe the surface topography of living endothelial cells in confluent monolayers maintained in static culture or subjected to unidirectional shear stress in laminar flow (12 dyne/cm2 for 24 hours). The surface of polygonal unsheared cells was smooth, with mean excursion of surface undulation between peak height (over the nucleus) and minima (at intercellular junctions) of 3.4 +/- 0.7 microns (mean +/- SD); the mean height to length ratio was 0.11 +/- 0.02. In cells that were aligned in the direction of flow after a 24-hour exposure to laminar shear stress, height differentials were significantly reduced (mean, 1.8 +/- 0.5 micron), and the mean height to length ratio was 0.045 +/- 0.009. Calculation of maximum shear stress and maximum gradien...
Visualization of the distance between perfusion and anoxia along an ischemic border.
Authors: M BSimson, WHarden, CBarlow, A HHarken
Journal: Circulation (1979)

The distance between perfusion and anoxia was measured on the border of an experimental ischemic area in the rabbit heart. Reduced nicotinamide adenine dinucleotide (NADH) fluorescence photography was used to detect myocardial anoxia. Fluorescein angiography marked areas of myocardial perfusion. The hearts were isolated, perfused with a hemoglobin-free solution and performed no external work. In all hearts there was a narrow band between areas of perfusion and anoxia that measured 329 +/- 42 mu (mean +/- SD). The transition from minimal to full NADH fluorescence was abrupt, less than 80 mu. We conclude that the normoxic/anoxic transition is sharp, and the gap between perfusion and anoxia is narrow along an ischemic border in the isolated heart performing no external work. These data suggest that in the vivo working heart the gap between perfusion and anoxia would be even narrower.
Acute hypertension selectively potentiates constrictor responses of large coronary arteries to serotonin by altering endothelial function in vivo.
Authors: K GLamping, W PDole
Journal: Circulation Research (1987)

We tested the hypothesis that acute coronary artery hypertension may damage vascular endothelium and alter vasomotor responses to humoral agents. We examined effects of intracoronary infusion of the endothelium-dependent agent serotonin and two endothelium-independent agents, angiotensin II and methoxamine, on large coronary artery diameter in the blood perfused dog heart. Responses were examined before and 30 minutes after brief periods of coronary hypertension (200 mm Hg for 10 seconds to 15 minutes). In open-chest anesthetized dogs, the left anterior descending coronary artery was perfused at constant pressure. Coronary diameter (D) was measured with piezoelectric crystals. At a control perfusion pressure of 80 mm Hg, serotonin produced dose-dependent constriction of the large coronary artery (mean +/- SEM; delta D = -22 +/- 10 microns at 5 micrograms/min; -108 +/- 50 microns at 50 micrograms/min). Increasing perfusion pressure to 200 mm Hg increased flow 515 +/- 79% and coronary diameter 509 +/- 9 mic...
Atrial contribution to ventricular filling in mitral stenosis.
Authors: J SMeisner, GKeren, O EPajaro, AMani, J AStrom, R WFrater, SLaniado, E LYellin
Journal: Circulation (1991)

BACKGROUNDThe importance of the contribution of atrial systole to ventricular filling in mitral stenosis is controversial. The cause of reduced cardiac output following the onset of atrial fibrillation may be due to an increased heart rate, a loss of booster pump function, or both.METHODS AND RESULTSWe studied the atrial contribution to filling under a variety of conditions by combining noninvasive studies of patients with computer modeling. Thirty patients in sinus rhythm with mild-to-severe stenosis were studied with two-dimensional and Doppler echocardiography for measurement of mitral flow velocity and mitral valve area (MVA). The mean +/- SD atrial contribution to left ventricular filling volume was 18 +/- 10% and varied inversely with mitral resistance. Patients with mild mitral stenosis (MVA, 1.8 +/- 0.7 cm2) and severe mitral stenosis (MVA, 0.9 +/- 0.2 cm2) had atrial contributions of 29 +/- 4% and 9 +/- 5%, respectively. The pathophysiological mechanisms responsible for these trends were further ...
Shall The Journal be Removed to Washington?
Authors: E. N. Brush
Journal: JAMA (1891)

<h3>To the Editor:</h3> —Except as I desire to seeThe Journalrepresent the best thought and the highest standard of the American medical profession, I am in no way interested in its place of publication nor in who edits it. I do not know the origin of the agitation to takeThe Journalto Washington, but I surmise that it arose out of a feeling that some change was desirable. I do not know how much editing the present editors feel justified in performing, nor exactly what is meant by the term "supervising editor " employed by Dr. Reed in his communication inThe Journalof March 28, but certainly the "supervision " has been somewhat lax. Doctors are not always good writers, I have no reference to the old illegible prescription story, I mean that they do not always pay much attention to the rules of grammar or composition. And even
SAT0715-HPR BREAKING BAD: REPORTING OF VERTEBRAL FRAGILITY FRACTURES AND THE IMPACT TO MANAGEMENT OF BONE HEALTH
Authors: Ann O’ Riordan, Shehla Farrukh, Fahd Adeeb
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> Vertebral fragility fracture (VFF) is the most common osteoporotic fracture and a strong predictor for future vertebral fracture(s) and/or hip fracture. A clear reporting of VFF by radiologists offers ample opportunity for early diagnosis and appropriate management of osteoporosis among treating physicians. <h3>Objectives:</h3> The objectives of this study were two-fold; to evaluate 1) the reporting of VFF by radiologists at one of the largest acute hospitals in southern Ireland 2) the management of osteoporosis (adherence to screening for secondary causes and commencement/switching of anti-resorptive therapy accordingly) for patients with VFF. <h3>Methods:</h3> We conducted a retrospective cross sectional study involving all patients (n=199) who attended our specialist rheumatology outpatient clinics at University Hospital Kerry during the month of November 2018. Patients who previously had undergone plain radiography of the spine (PRS) in the previous 5 years were identified and reassessed for evidence of VFFs. Basic demographic, drug history, clarification of fragility fracture and previous related trauma, investigations for secondary causes of osteoporosis, and treatment received for osteoporosis were documented. <h3>Results:</h3> 73 of the 199 patients had undergone previous PRS, 9 of which had evidence for VFFs. Only two patients (22.2%) were reported as having vertebral "fractures", while 7 others had different terms used to describe the fracture(s)-2 patients with "wedging", 1 with "compression", 2 with "loss of height" and 2 with "collapse". All (2 patients; 100%) with VFF reported as "fracture" had complete clarification of VFF, secondary osteoporotic work-up and treated with anti-resorptive therapy accordingly. Among the other 7 patients with VFFs but not reported as having "fracture", 1 patient had concomitant report of "osteoporotic" bones and had complete management for osteoporosis. 4 patients had concomitant report of "osteopenia", 3 (75%) of which received complete management for osteoporosis; while only 50% (1 patient) of the 2 remaining patients without further description of bone density received appropriate management. Further 6 patients with non-VFF were reported to have reduced bone density (1 reported as "osteoporotic" bones; 5 as "osteopenic" bones). Only one of them (16.7%) had further work-up, evaluation and management for osteoporosis. <h3>Conclusion:</h3> Clear radiological report of PRS with VFFs using the word "fracture" is a strong predictor for appropriate management of bone health. It is essential that other terms used to describe VFFs such as "wedging", "compression", "loss of height" and "collapse" not to be used alone without the concomitant use of the word "fracture". <h3> Disclosure of Interests:</h3> None declared
Relative contributions of cardiopulmonary and sinoaortic baroreflexes in causing sympathetic activation in the human skeletal muscle circulation during orthostatic stress.
Authors: T NJacobsen, B JMorgan, UScherrer, S FVissing, R ALange, NJohnson, W SRing, P SRahko, PHanson, R GVictor
Journal: Circulation Research (1993)

The aim of this study was to reexamine the hypothesis that cardiopulmonary baroreflexes are more important than sinoaortic baroreflexes in causing vasoconstriction in the skeletal muscle circulation during orthostatic stress. We recorded muscle sympathetic nerve activity (MSNA) with microelectrodes in the peroneal nerve (and forearm blood flow with venous occlusion plethysmography) in normal subjects (innervated ventricles) and in heart transplant recipients (denervated ventricles) during graded lower body negative pressure (LBNP) performed alone and in combination with intravenous infusion of phenylephrine, which was titrated to eliminate the orthostatically induced fall in blood pressure and thus the unloading of both carotid and aortic baroreceptors. The principal new findings are as follows: (1) The increases in both MSNA and forearm vascular resistance during multiple levels of LBNP were not attenuated by heart transplantation, which causes ventricular but not sinoaortic deafferentation. (2) In heart...
Efficacy and safety of perhexiline maleate in refractory angina. A double-blind placebo-controlled clinical trial of a novel antianginal agent.
Authors: P LCole, A DBeamer, NMcGowan, C OCantillon, KBenfell, R AKelly, L HHartley, T WSmith, E MAntman
Journal: Circulation (1990)

Despite large gains in the medical and surgical treatment of angina pectoris in the past two decades, many patients are refractory to conventional medical therapy and are unsuitable for a first or, more commonly, repeat coronary revascularization procedure. We evaluated the efficacy of perhexiline maleate, a drug with an antianginal mechanism of action in humans that is as yet unknown, by using a randomized double-blind placebo-controlled crossover design in 17 patients with refractory angina who continued to receive maximal antianginal therapy, typically including nitrates, a beta-blocker, and a calcium channel antagonist. In view of perhexiline's potential for hepatic and neurological toxicity, plasma drug levels were monitored and maintained in the 150-600 ng/ml range. Sixty-three percent of patients were judged perhexiline responders by objective exercise testing criteria, as compared with 18% of patients on placebo (p less than 0.05). By blinded review of subjective measures of anginal frequency and ...
Left anterior hemiblock obscuring the diagnosis of right bundle branch block in acute myocardial infarction.
Authors: SSclarovsky, R FLewin, BStrasberg, JAgmon
Journal: Circulation (1979)

Thirty cases in which transient left anterior hemiblock (LAHB) obscured the diagnosis of right bundle branch block (RBBB) appearing during the first days of an acute myocardial infarction (AMI) are presented. Twenty-eight of the patients with AMI had a clear septal wall involvement, while the remaining two had an anterolateral and lateral wall AMI, respectively. These intraventricular conduction defects developed 2-120 hours (mean 64.9 +/- 26 hours) after the acute event, and persisted for 24 hours to 7 days (mean 63.1 +/- 35 hours). The ECG was characterized by a pure LAHB with wide QRS complexes and the presence of RBBB was shown by recording high V1 and right-sided chest leads. The vectorcardiogram was also useful in several cases. The clinical course of this type of bifascicular block was transient and benign, with an in-hospital mortality of 6.7%. No patient developed trifascicular or complete atrioventricular block and, therefore, we conclude that prophylactic installation of a temporary pacemaker i...
Regulation of fos and jun immediate-early genes by redox or metabolic stress in cardiac myocytes.
Authors: K AWebster, D JDischer, N HBishopric
Journal: Circulation Research (1994)

We have previously demonstrated coordinate inductions of c-fos, c-jun, jun B, and jun D in cardiac myocytes exposed to hypoxia for 2 to 4 hours. Induction of these transcripts occurred before any significant loss of intracellular ATP. In the present study, the origin of the signal(s) that regulates immediate-early gene induction was investigated by comparing the effects of hypoxia with those of the metabolic inhibitors cyanide, deoxyglucose and cyanide combined, and iodoacetic acid. Cyanide, an inhibitor of oxidative metabolism, closely mimicked the metabolic effects of hypoxia, with elimination of oxygen consumption, increased lactate production, and minimal decline in ATP levels under both conditions. Compared with hypoxia, cyanide mediated small transient inductions of fos and jun transcripts that followed a different time course. The combination of cyanide and deoxyglucose resulted in inhibition of lactate production as well as respiration, and ATP dropped rapidly to 20% of control levels. The loss of...
Canine myocardial reperfusion injury. Its reduction by the combined administration of superoxide dismutase and catalase.
Authors: S RJolly, W JKane, M BBailie, G DAbrams, B RLucchesi
Journal: Circulation Research (1984)

Therapy directed against the toxic effects of reactive oxygen species may reduce the final extent of ischemic injury in otherwise viable tissue irreversibly injured by the abrupt reoxygenation of reperfusion. In four groups of dogs, superoxide dismutase plus catalase (groups I-III) or saline (controls) (group IV) was infused into the left atrium. Group I received the infusion for 2 hours, beginning 15 minutes before occlusion of the left circumflex coronary artery (90 minutes) and ending 15 minutes after reperfusion. Group II received the infusion for 1 hour starting 15 minutes before reperfusion. Group III received the infusion for 1 hour beginning 40 minutes after reperfusion. Dogs were killed the next day, and infarct size was determined by dissection and weighing, and confirmed histologically. Infarct size expressed as percent of the anatomic area at risk was: group I, 19.4 +/- 5.0; group II, 21.8 +/- 3.3; group III, 47.6 +/- 10.3; group IV, 43.6 +/- 3.5 (mean +/- SEM). Analysis of variance followed b...