tbuckley/cabot-search huggingface dataset:
Aortic stenosis in elderly patients aged 80 or older. Treatment by percutaneous balloon valvuloplasty in a series of 92 cases.
Authors: BLetac, ACribier, RKoning, ELefebvre
Journal: Circulation (1989)

Very elderly patients with severe aortic stenosis will probably benefit from percutaneous balloon valvuloplasty. Ninety-two patients, aged 80 or older (mean age, 84 +/- 3.7 years) and all severely incapacitated (18 with an associated pathologic condition or in critical condition with terminal heart failure), underwent a valvuloplasty procedure. Femoral access was used in all cases except seven (8%), in whom the femoral route had to be abandoned and the brachial approach was used due to severe arterial tortuosity. Peak-to-peak ventriculoaortic gradient decreased from 71 +/- 27 to 27 +/- 15 mm Hg, and the aortic valve area increased from 0.48 +/- 0.16 to 0.91 +/- 0.35 cm2 (p less than 0.01). Thirty-two percent had a postprocedure aortic valve area more than or equal to 1 cm2. The final valve area was less than or equal to 0.7 cm2 in 30% of the patients. There were three deaths (ages, 82, 92, and 98 years) in the procedure room. One stroke occurred 1 day after the procedure. Hematoma or thrombosis at the fem...
Importance of two-dimensional echocardiographic assessment of left ventricular systolic function in patients presenting to the emergency room with cardiac-related symptoms.
Authors: PSabia, R DAbbott, AAfrookteh, M WKeller, D ATouchstone, SKaul
Journal: Circulation (1991)

BACKGROUNDThis prospective study was designed to test the hypothesis that the assessment of left ventricular systolic function at the time of emergency room (ER) presentation provides valuable diagnostic and prognostic information in patients with cardiac-related symptoms.METHODS AND RESULTSThe study is based on a 2-year follow-up of 171 consecutive patients evaluated in the ER for such symptoms. In the course of follow-up, one third of the patients (55 of 171) suffered a major cardiac event. For those with left ventricular systolic dysfunction (LVSD), the age-adjusted rate of early events (occurring within 48 hours of presentation) was more than eight times higher than for those without LVSD (26.9% versus 3.3%, p less than 0.01). For events occurring after 48 hours of ER presentation, LVSD was associated with a nearly fourfold excess of cardiac events (23.9% versus 6.4%, p less than 0.01). Other than advanced age, the most important confounder for early events included an abnormal electrocardiogram diagn...
Evidence for cholinergically mediated vasodilation at the beginning of isometric exercise in humans.
Authors: J SSanders, A LMark, D WFerguson
Journal: Circulation (1989)

Vasodilation occurs in the nonexercising forearm at the beginning of isometric handgrip despite activation of sympathetic vasoconstrictor reflexes. The mechanism of this response remains unclear. In 33 normal humans, age 24 +/- 1 years (mean +/- SEM), we measured mean arterial pressure, heart rate, and forearm blood flow (plethysmography) in the nonexercising arm during sustained contralateral isometric handgrip at 30% maximal voluntary contraction. Sympathetic nerve activity to calf muscles (microneurography) was also measured in 15 subjects. Handgrip resulted in increases in arterial pressure from 86 +/- 2 to 97 +/- 3 mm Hg (p less than 0.05). Despite increases in nerve activity to calf muscles from 229 +/- 43 to 337 +/- 66 units (p less than 0.005), which would be expected to produce forearm vasoconstriction, forearm vascular resistance in the contralateral resting arm decreased from 20 +/- 3 to 18 +/- 2 units (p less than 0.05). To determine the mechanism of this vasodilatory influence, additional stu...
Effectiveness of unsupervised and supervised high intensity physical training in normalizing serum lipids in men with type iv hyperlipoproteinemia.
Authors: R MLampman, J TSantinga, D RBassett, NMercer, W OBlock, J DFlora, M LFoss, W GThorland
Journal: Circulation (1978)

The effect of high intensity physical training (HIPT), conducted in an unsupervised (group A) or supervised (group B) setting, was studied in 23 middle-aged men with Type IV hyperlipoproteinemia (HLP). Following 10 weeks of HIPT intervention, significant metabolic changes were observed such as reductions in both fasting triglyceride and insulin levels, but no changes in fasting serum cholesterol or glucagon levels were found. Other favorable results noted included a significant improvement in physical fitness, as measured by increases in aerobic power, and a decrease in body fatness with only minimal weight losses. There were no significant differences in the results when groups A and B were compared. It was concluded that HIPT is an effective means of lowering fasting triglyceride and insulin levels in Type IV HLP individuals. In addition, such physical training programs can be conducted in either an unsupervised or supervised setting, provided the subjects are highly motivated.
Vasoreactivity of the culprit lesion in unstable angina.
Authors: PBogaty, DHackett, GDavies, AMaseri
Journal: Circulation (1994)

BACKGROUNDAlthough abnormal vasoconstriction may be involved in the pathogenesis of the acute coronary syndromes, the vasoreactivity of the lesion responsible for unstable angina (culprit lesion) has not been directly investigated. It is also unknown if enhanced vasoreactivity is found downstream to this lesion or extends to uninvolved coronary arteries.METHODS AND RESULTSWe studied seven unstable angina patients whose condition had sufficiently stabilized to allow ergometric bicycle exercise and a cold pressor test to be performed as provocative stimuli during coronary arteriography. We measured the luminal diameter of the culprit lesion, a normal-appearing distal segment, and the segment of an uninvolved coronary artery using quantitative coronary angiography. Seven stable angina patients served as controls. Antianginal medications were tapered and interrupted. The culprit lesion constricted significantly with exercise and the cold pressor test compared with a stable angina control lesion. The culprit l...
The time course of action potential repolarization affects delayed afterdepolarization amplitude in atrial fibers of the canine coronary sinus.
Authors: BHenning, A LWit
Journal: Circulation Research (1984)

The effects of changing the time course of action potential repolarization on the amplitude and coupling interval of delayed afterdepolarizations were studied in small preparations of coronary sinus atrial fibers exposed to catecholamines. Repolarization was accelerated or retarded by current pulses passed through an intracellular microelectrode in the depolarizing or repolarizing direction. Acceleration of repolarization decreased the amplitude of delayed afterdepolarizations, prolonged their coupling interval to the action potential upstroke, and prevented triggered activity. Prolonging the time for repolarization increased afterdepolarization amplitude, shortened the coupling interval, and caused triggered activity. The afterdepolarization amplitude and coupling interval had a linear relationship to the duration of the action potential plateau. In some preparations, the action potential plateau increased spontaneously at stimulation rates that caused afterdepolarization amplitude to increase and trigge...
Cardiac tamponade: hemodynamic observations in man.
Authors: P SReddy, E ICurtiss, J DO'Toole, J AShaver
Journal: Circulation (1978)

Hemodynamic studies were performed before and after pericardiocentesis in 19 patients with pericardial effusion. Right atrial pressure decreases significantly, from 16 +/- 4 mm Hg (mean +/- SD) to 7 +/- 5 mm Hg in 14 patients with cardiac tamponade. This change was accompanied by significant increases in cardiac output (3.87 +/- 1.77 to 7 +/- 2.2 l/min) and inspiratory systemic arterial pulse pressure (45 +/- 29 to 81 +/- 23 mm Hg). The remaining five patients did not demonstrate cardiac tamponade, as evidenced by lack of significant change in these hemodynamic parameters. In all patients with tamponade, right ventricular end-diastolic pressure (RVEDP) was elevated and equal to pericardial pressure; equilibration was uniformly absent in patients without tamponade. During gradual fluid withdrawal in the tamponade group, significant hemodynamic improvement was largely confined to the period when right ventricular filling pressure remained equilibrated with pericardial pressure. In 10 patients with tamponade...
Intraaortic balloon counterpulsation with and without reperfusion for myocardial infarction shock.
Authors: M ADeWood, R NNotske, G RHensley, J PShields, W PO'Grady, JSpores, MGoldman, J HGanji
Journal: Circulation (1980)

Forty patients were treated for cardiogenic shock secondary to acute myocardial infarction. Twenty-one (group 1) were treated with intraaortic balloon counterpulsation and 19 (group 2) were treated with counterpulsation and coronary artery bypass grafting. The groups were similar in age, incidence of previous infarction, initial hemodynamics and coronary anatomy. The in-hospital mortality between group 1 (52.4%) and group 2 (42.1%) was not significantly different. The difference in long-term mortality between group 1 and group 2 was substantially different (71.4% vs 47.3%). The subset of group 2 (n = 12) that underwent reperfusion and counterpulsation within 16 hours from the onset of symptoms of infarction had a lower mortality (25.0%) than the subset (n = 7) that underwent operation more than 18 hours after the onset of symptoms (71.4%). The long-term mortality in the subset of group 2 patients operated on within 16 hours after the onset of infarction was significantly different from that in group 1 (25...
Regulation of Ca2+ channels by cAMP and cGMP in vascular smooth muscle cells.
Authors: TIshikawa, J RHume, K DKeef
Journal: Circulation Research (1993)

Whole-cell Ca2+ channel currents in rabbit portal vein cells were recorded using the amphotericin B-perforated patch-clamp technique at 35 degrees C. This technique allowed recording of stable inward currents in the absence of run-down for more than 30 minutes. Depolarizing voltage steps from a holding potential of -70 mV elicited voltage-dependent inward currents. The voltage dependence of inward currents measured in either 2.5 mmol/L Ba(2+)- or 2.5 mmol/L Ca(2+)-containing solution were very similar. However, maximum Ba2+ current (obtained at around +10 mV) was approximately 1.5-fold larger than maximum Ca2+ current. Changing the holding potential from -70 to -40 mV decreased inward currents but did not shift the voltage dependence significantly. Inward currents were also completely blocked by the dihydropyridine Ca2+ channel blocker, nicardipine (10 mumol/L), suggesting the presence of predominantly L-type Ca2+ channels in rabbit portal vein cells. Isoproterenol caused small increases in the amplitude ...
Selective removal of astrocytic APOE4 strongly protects against tau-mediated neurodegeneration and decreases synaptic phagocytosis by microglia
Authors: Chao Wang, Monica Xiong, Maud Gratuze, Xin Bao, Yang Shi, Prabhakar Sairam Andhey, Melissa Manis, Caitlin Schroeder, Zhuoran Yin, Charlotte Madore, Oleg Butovsky, Maxim Artyomov, Jason D. Ulrich, David M. Holtzman
Journal: Neuron (2021)
Advantages and applications of the centerline method for characterizing regional ventricular function.
Authors: F HSheehan, E LBolson, H TDodge, D GMathey, JSchofer, H WWoo
Journal: Circulation (1986)

We sought to identify theoretical advantages and applications of the centerline method for quantitative assessment of regional ventricular function. Motion was measured along 100 chords constructed perpendicular to a centerline drawn midway between the end-diastolic and end-systolic contours, and normalized for heart size. Abnormality was expressed in units of standard deviations from the mean motion in a normal reference population to indicate both the severity and significance of the wall motion abnormality. The mean abnormality averaged over 100 chords correlated highly with the area ejection fraction (r = .97). The centerline method uses a sliding window to measure motion where it is abnormal, because assessment of wall motion in predefined regions of the ventricular contour underestimates abnormality. From the 100 data points, the extent (% of contour) of regional abnormalities can also be determined. The severity of hypokinesis at the site of acute myocardial infarction correlated better with infa...
Rate-dependent prolongation of cardiac action potentials by a methanesulfonanilide class III antiarrhythmic agent. Specific block of rapidly activating delayed rectifier K+ current by dofetilide.
Authors: N KJurkiewicz, M CSanguinetti
Journal: Circulation Research (1993)

Class III antiarrhythmic agents act by selective prolongation of cardiac action potential duration (APD). Methanesulfonanilide class III agents (e.g., E-4031 and dofetilide) are extremely potent and lengthen action potentials in a reverse rate-dependent manner; i.e., effects are greater at low compared with high rates of stimulation. By using the whole-cell current-clamp technique in isolated guinea pig ventricular myocytes, APD was shortened by rapid pacing (244 +/- 16 msec at 30 pulses per minute, 166 +/- 8 msec at 240 pulses per minute; n = 8). Dofetilide (1 microM) prolonged APD more when cells were stimulated at the rate of 30 pulses per minute (44 +/- 10-msec increase) than at 240 pulses per minute (21 +/- 5-msec increase). We investigated the mechanism of APD prolongation using voltage-clamp techniques. Dofetilide selectively inhibited IKr (IC50, 31.5 nM), defined as the rapidly activating inward rectifying component of net delayed rectifier K+ current (IK), without effects on the larger but more...
High tumor angiogenesis is associated with poorer survival in carcinoma of the cervix treated with radiotherapy
Authors: Cooper, Wilks, Logue, Davidson, Hunter, Roberts, West
Journal: Clinical Cancer Research (1998)

The purpose of this study was to examine the relationship between tumor angiogenesis and prognosis in carcinoma of the cervix treated with radiotherapy with a median follow-up time of 55 months. A retrospective study was carried out on 111 patients. Formalin-fixed, paraffin-embedded tumor biopsies were stained with anti-factor VIII using immunohistochemistry. Tumor angiogenesis was assessed by scoring the distance to the closest microvessel from random points within the tumor and the intratumor microvessel density (IMD) in the areas of highest neovascularization, High vascularity, as measured by both methods, was associated with a poor prognosis but was only significant for IMD. The ii-year survival rates for tumors with high versus low values were 50 and 65%, respectively. ND was a significant prognostic factor within a Cox multivariate analysis, Higher tumor vascularity was associated with lower overall survival and locoregional control, but this association was not significant in the case of metastasis-free survival, The method used to assess tumor vascularity is important, The level of angiogenesis in carcinoma of the cervix is an independent prognostic parameter
Chest wall velocity and the second heart sound. An improved sensor of S2 splitting.
Authors: DSmith, YOzawa, ECraige
Journal: Circulation (1983)

We report a new method of detection of the timing of the aortic and pulmonary valve closure that depends not on the registration of audible vibrations, but rather, on subtle but distinct movements of the chest wall, which are external manifestations of these events. We studied these phenomena in six open-chest dogs and in 69 human subjects. The dog studies show that the two distinct inward movements detected by a motion sensor applied to the epicardium in the vicinity of the right ventricular outflow tract correlate with the timing of the incisural notches of the pressure signals from the great vessels. In humans, these movements are transmitted to the skin surface and can be detected noninvasively. In 48 of the 69 human subjects (70%), these spikes provided a significantly better indication of the timing of semilunar valve closure than did the conventional phonocardiogram.
Interobserver variability in coronary angiography.
Authors: L MZir, S WMiller, R EDinsmore, J PGilbert, J WHarthorne
Journal: Circulation (1976)

Four experienced coronary angiographers (two radiologists and two cardiologists) independently assessed the location and degree of coronary artery stenosis, and the location and degree of left ventricular wall motion abnormalities in 20 coronary angiograms. Marked interobserver variability was noted in quantifying percent coronary artery stenosis and degree of left ventricular wall motion abnormalities. For example, in only 13/20 (65%) of the coronary angiograms did all observers agree about the significance of a stenosis (defined as greater than 50% in diameter luminal narrowing) in the proximal or mid left anterior descending coronary artery. In 3/20 (15%) angiograms there was disagreement by at least one observer about the significance of lesions noted in the main left coronary artery. The ventricle was divided into five segments and the degree of wall motion abnormality graded into six categories of increasing severity from normal to dyskinesis. There was a 42% mean disagreement among all four observe...
Effects of adenosine and its analogues on isolated intracerebral arterioles. Extraluminal and intraluminal application.
Authors: A CNgai, H RWinn
Journal: Circulation Research (1993)

We evaluated the responses of brain parenchymal arterioles to intraluminal and extraluminal application of adenosine and its analogues. Intracerebral arterioles (28.4- to 60.3-microns diameter) were isolated from Sprague-Dawley rats, cannulated with micropipettes, and perfused in vitro. Both extraluminal and intraluminal adenosine, 5'-(N-ethylcarboxamido)adenosine (NECA), R-N6-(phenylisopropyl)adenosine (R-PIA), and S-N6-(phenylisopropyl)adenosine (S-PIA) elicited concentration-dependent dilation of these arterioles, but intraluminal application was less potent and efficacious than extraluminal application. Inosine was not vasoactive. A common order of agonist potency (NECA > adenosine > R-PIA > or = S-PIA) was determined for both extraluminal and intraluminal application. Theophylline (10 microM) caused a rightward shift of the adenosine concentration-response curve and a 50-fold reduction in potency. Intraluminal theophylline was one sixth as effective as extraluminal theophylline in antagonizing the ex...
Background potassium current active during the plateau of the action potential in guinea pig ventricular myocytes.
Authors: P HBackx, EMarban
Journal: Circulation Research (1993)

Background outward K+ currents in guinea pig ventricular myocytes were characterized over a broad range of membrane potentials, including those corresponding to the plateau of the action potential. The background current that is blocked by 1 mM Ba2+ (IK,p) activates within 5 msec at positive potentials, does not inactivate, and deactivates very rapidly on repolarization. IK,p is insensitive to Cl- channel blockers, internal or external [Cl-], dihydropyridines, and sulfonylureas. In contrast, the delayed rectifier K+ current (IK) was not completely blocked even by 30 mM Ba2+. Ba(2+)-sensitive current density increased progressively from 0.16 +/- 0.04 pA/pF at 0 mV to 0.52 +/- 0.21 pA/pF at +80 mV (n = 13, mean +/- SEM). The background current remains present when [K+]o is reduced to 0 mM, which suppresses the inward rectifier K+ current (IK1). These and other features suggest that IK,p is generated by K+ channels that are distinct from IK1 or IK. The kinetics and voltage dependence of IK,p render it capabl...
ST segment changes post-infarction: predictive value for multivessel coronary disease and left ventricular aneurysm.
Authors: D AWeiner, CMcCabe, M DKlein, T JRyan
Journal: Circulation (1978)

To ascertain whether exercise testing might predict multivessel coronary disease and left ventricular aneurysm after a myocardial infarction, 154 patients with a single documented myocardial infarction who had both exercise testing and coronary angiography were grouped according to whether they had greater than or equal to 1 mm ST depression, greater than or equal to 1 mm ST elevation, or neither during exercise testing: 83 patients developed ST depression alone (group 1); 22 patients had ST elevation with concomitant ST depression in other leads (group 2); 19 patients had ST elevation alone (group 3); and 30 patients had no ST changes (group 4). Multivessel disease, defined as greater than or equal to 70% luminal narrowing in two or more coronary vessels, was present in 76% (63 of 83) of group 1, 91% (20 of 22) of group 2, 21% (four of 19) of group 3, and 13% (four of 30) of group 4. A left ventricular aneurysm was present in 31% (26 of 83) of group 1, 68% (15 of 22) of group 2, 79% (15 of 19) of group 3...
Suppression of ouabain-induced ventricular rhythms with aprindine HCl. A comparison with other antiarrhythmic agents.
Authors: P RFoster, R MKing, A BNicoll, D PZipes
Journal: Circulation (1976)

Three groups of dogs were given ouabain (mean 60 mug/kg) until an accelerated ventricular escape (AVE) and repetitive ventricular response (RVR) followed cessation of pacing. In a group of six control dogs, the AVE and RVR were found to occur at stable escape intervals for periods of at least three hours. A second group of dogs received various antiarrhythmic agents in an attempt to suppress the AVE and RVR. Quinidine, diphenylhydration, lidocaine, procainamide, and propranolol, were successful in only 0 to 33% of trials. Potassium canrenoate, 12 mg/kg was unsuccessful in three dogs. Verapamil, by bolus, suppressed RVR in 41% and AVE in 21% of trials. KCl, infused until AVE and RVR were suppressed, was successful when the mean serum potassium rose from 3.8 mEq/L to 7.2 mEq/L. Aprindine, 2.86 mg/kg, suppressed AVE and RVR in 14 of 14 dogs. In the third group of dogs, verapamil was infused continuously and suppressed RVR and AVE at a mean cumulative dose of 2.93 mg/kg. Calcium chloride reversed aprindine an...
Pregnancy in primary sclerosing cholangitis
Authors: A. Gossard, K. Lindor
Journal: Gut (2011)

Pregnancy in primary sclerosing cholangitis (PSC) is not well studied. There is little known regarding how pregnancy might affect PSC, and how the disease might affect the fetus. In general, advice regarding conception for a woman with PSC reflects knowledge gleaned from a few small studies and case reports 1–5 A common question for a newly diagnosed patient with PSC pertains to future fertility and childbearing. The case series published in this issue of Gut by Wellge and colleagues6 ( see page 1117 ) provides an important look at pregnancy in PSC. In the review by Wellge et al , 229 patients with PSC were evaluated as were 569 healthy controls. The authors found that the number of children was not different between the two groups. This would imply that fertility was not affected by the diagnosis of PSC. A total of 17 patients with known PSC and …