tbuckley/cabot-search huggingface dataset:
Polymorphous ventricular tachycardia: clinical characterization, therapy, and the QT interval.
Authors: P TNguyen, M MScheinman, JSeger
Journal: Circulation (1986)

Forty-five consecutive patients with polymorphous ventricular tachycardia (PVT) were studied. The arrhythmia proved to be of a drug-related cause in 27 and due to an electrolyte disorder in four patients. Coexistent cardiac diseases without metabolic or drug-related abnormalities included ischemic heart disease in three, cardiomyopathy in three, and mitral valve prolapse in two. PVT was exercise-induced in four and associated with bradyarrhythmias in two. A prolonged QT or corrected QT interval was inconsistently related to the occurrence of PVT. In patients in whom PVT was induced by certain type I drugs, other type I antiarrhythmic drugs were usually either ineffective or resulted in aggravation of arrhythmia. For the group as a whole, treatment with lidocaine resulted in inconsistent beneficial effects, while cardiac pacing was almost universally effective for those with drug-induced PVT, regardless of the length of the QT interval. Long-term amiodarone therapy proved safe and effective for 12 of the 2...
Subsets of ambulatory myocardial ischemia based on heart rate activity. Circadian distribution and response to anti-ischemic medication. The Angina and Silent Ischemia Study Group (ASIS)
Authors: T CAndrews, TFenton, NToyosaki, S PGlasser, P MYoung, GMacCallum, R SGibson, T LShook, P HStone
Journal: Circulation (1993)

BACKGROUNDIdentification of whether episodes of ambulatory ischemia are caused by increases in myocardial oxygen demand or to episodic coronary vasoconstriction in patients with stable coronary disease may be important to guide selection of optimal anti-ischemic therapy and to gain insight into mechanisms responsible for adverse cardiac events.METHODS AND RESULTSMean minute heart rate activity during ambulatory ECG (AECG) monitoring was determined for 50 patients treated with propranolol, diltiazem, nifedipine, or placebo in a randomized, double-blind, crossover trial. Periods of heart rate increases of various magnitudes and durations and starting at various baseline heart rates on each therapy were identified throughout each 48-hour AECG recording, and the proportion of these periods associated with an ischemic episode was determined. The circadian variation of ischemic episodes categorized by the presence or absence of an increase in heart rate was analyzed. Eighty-one percent of ischemic episodes were...
How large is the problem of medical negligence?
Authors: J. Davis
Journal: BMJ (1984)

The prognosis of the disease appears to be more accurately indicated by the intensity with which Helix pomatia lectin binds to primary breast cancer cells than by lymph node involvement.This binding reflects expression of N-acetyl-galactosaminyl glyco- conjugates in the cancer cells.There may be many different glycoconjugates but it would be interesting to know whether CA 50 contains N-acetyl-galactosamine.Professor Holmgren's group suggests that formation of new abnormal carbohydrate structures may be caused by activation of normally unexpressed glycosyltransferases.The observed changes, however, could be due to increased levels of normal glycosyltransferases.We raised an antibody to sialytransferase isolated from human milk, and found a tendency for primary breast cancer with a poor prognosis to show greater binding of this antibody than cancer with a good prognosis.This finding is also of interest because increased sialic acid concentrations have been implicated in increased metastatic potential.
Characteristics of adrenoceptors and [3H]nitrendipine receptors of porcine vascular smooth muscle: differences between coronary artery and aorta.
Authors: JNishimura, HKanaide, MNakamura
Journal: Circulation Research (1987)

Characteristics of the bindings of [3H](-)dihydroalprenolol, [125I](-)iodocyanopindolol, [3H]prazosin, [3H]yohimbine, and [3H]nitrendipine to porcine coronary membranes were investigated and the results compared with studies of porcine aortic membranes. In the equilibrium binding study carried out in sarcolemma-enriched fractions, there were no major differences in the Kd values of these radioligands between coronary artery and aorta. However, the densities of beta-, alpha 1-, and alpha 2-adrenoceptors and [3H]nitrendipine receptors of coronary artery were 258, 12, 12, and 561 fmol/mg protein, respectively, while those of aorta were 37, 525, 1,000, and 215 fmol/mg protein. beta-Adrenergic agonists competed with [3H](-)dihydroalprenolol binding sites in coronary artery, the order of potency being (-)isoproterenol greater than (-)norepinephrine greater than (-)epinephrine greater than (+)isoproterenol. In case of aorta, the order was (-)isoproterenol greater than (-)epinephrine greater than (-)norepinephrin...
Internal cardioversion of atrial fibrillation in sheep.
Authors: R ACooper, C AAlferness, W MSmith, R EIdeker
Journal: Circulation (1993)

BACKGROUNDThe cardioversion efficacy of multiple defibrillation waveforms and electrode systems was compared in a sheep model of atrial fibrillation.METHODS AND RESULTSSustained atrial fibrillation could be induced with rapid atrial pacing in 23 (55%) of the animals. This study was performed in four parts. Six sheep with sustained atrial fibrillation were used for data analysis for each part, except in part 4 where five sheep without sustained atrial fibrillation were used. In part 1, four lead systems and four single capacitor truncated exponential defibrillation waveforms (two monophasic and two biphasic) were tested. In part 2, two transvenous lead systems were compared; one was a right-to-left system with one electrode located in the right side of the heart and the other electrode located in the left side of the heart, and the other was a totally right-sided system with both electrodes located in the right side of the heart. Eight (four monophasic and four biphasic) waveforms were tested with each lea...
Emerging Trends in Cancer Drug Discovery—From Drugging the “Undruggable” to Overcoming Resistance
Authors: Joachim Rudolph, Jeff Settleman, Shiva Malek
Journal: Cancer Discovery (2021)

Technology advancement and the courage to challenge dogma have been key elements that have continuously shifted druggability limits. We illustrate this notion with several recent cancer drug-discovery examples, while also giving an outlook on the opportunities offered by newer modalities such as chemically induced proximity and direct targeting of RNA. Treatment resistance is a major impediment to the goal of durable efficacy and cure, but the confluence of new biological insights, novel drug modalities, and drug combinations is predicted to enable transformative progress in this decade and beyond.
The differential diagnosis of acute pericarditis from the normal variant: new electrocardiographic criteria.
Authors: L EGinzton, M MLaks
Journal: Circulation (1982)

We examined the quantitative electrocardiographic differentiation of acute pericarditis from normal variant ST-T changes. The ECGs of 19 patients with acute pericarditis were compared with those of 20 subjects with typical normal variant changes. Patients were excluded if their ECGs demonstrated conditions that markedly altered repolarization. The positive predictive values (PPV) and negative predictive values (NPV) of previously reported criteria were not high (PPV = 0.54-0.83, NPV = 0.56-0.58). In contrast, in the present study, a T-wave amplitude in lead V6 of less than or equal to 0.3 mV diagnosed acute pericarditis (p less than 0.005, PPV = 0.85, NPV = 0.85), but there was overlap of patients between the groups. The ratio of the amplitude of the onset of the ST segment to the amplitude of the T wave in that lead (ST/T ratio in V6) proved to be the most reliable discriminator. An ST/T ratio greater than or equal to 0.25 diagnosed all patients with acute pericarditis (p less than or equal to 0.005, PPV...
Congenital coronary artery obstruction associated with aortic anomalies in children: report of two cases.
Authors: RGibson, M RNihill, C EMullins, D ACooley, F MSandiford, D GMcNamara
Journal: Circulation (1981)

Coronary arterial obstruction associated with congenital aortic valve disease is rare in children. We studied two children with aortic valve disease and symptoms of coronary insufficiency. Cineangiography revealed localized obstruction of the proximal left coronary artery. In one patient, a membrane-like structure partially covered the left sinus of Valsalva, almost isolating the ostium of the left coronary artery; the other patient had severe stenosis of the proximal left coronary artery and a congenitally hypoplastic left coronary cusp. Surgical repair was successful in both cases. Symptoms of myocardial ischemia in children with aortic valve disease should be investigated promptly to exclude obstruction of the coronary arteries.
Noninvasive detection of intracardiac thrombosis: 131-I fibrinogen cardiac survey.
Authors: J HFrisbie, D ETow, A ASasahara, E MBarsamian, A FParisi
Journal: Circulation (1976)

Cardiac survey following administration of 131-1 autologous fibrinogen is a noninvasive technique for the detection of intracardiac thrombosis. Fibrinogen is isolated from plasma by a rapid salting-out method with ammonium sulfate and is iodinated with chloramine T. The purity of 131-fibrinogen, expressed as clottable radioactivity, is greater than 90%. Cardiac survey consisting of serial gamma camera imaging or rectilinear scanning after intravenous administration of 131-I fibrinogen was conducted in dogs with freshly induced thromobosis of the left atrial appendage. An accumulation of radioactivity was detectable in the area of the left atrium and confirmed in each of nine dogs sacrificed. Similarly, 20 patients with heart disease predisposing to intracardiac thrombosis were surveyed. Eight of nine patients with positive studies and 11 of 11 with negative studies were confirmed subsequently at surgery or autopsy. Cardiac survey with 131-I fibrinogen is a simple and noninvasive method of detecting intrac...
It Is Too Early to Declare Early or Late Rescue High-Frequency Oscillatory Ventilation Dead—Reply
Authors: Punkaj Gupta, Robert M. Kacmarek, Randall C. Wetzel
Journal: JAMA Pediatrics (2014)

Our website uses cookies to enhance your experience. By continuing to use our site, or clicking "Continue," you are agreeing to our Cookie Policy | Continue JAMA Pediatrics HomeNew OnlineCurrent IssueFor Authors Podcast Publications JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry (1919-1959) JN Learning / CMESubscribeJobsInstitutions / LibrariansReprints & Permissions Terms of Use | Privacy Policy | Accessibility Statement 2023 American Medical Association. All Rights Reserved Search All JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Forum Archive JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry Input Search Term Sign In Individual Sign In Sign inCreate an Account Access through your institution Sign In Purchase Options: Buy this article Rent this article Subscribe to the JAMA Pediatrics journal
Aspirin-induced increase in collateral flow after acute coronary occlusion in dogs.
Authors: N LCapurro, K CMarr, RAamodt, R EGoldstein, S EEpstein
Journal: Circulation (1979)

Aspirin (acetylsalicylic acid) has inhibitory effects on platelet function and prostaglandin synthesis. Since alterations in either platelet function or prostaglandin-mediated vascular responses could influence blood flow to ischemic myocardium, we tested the effects of aspirin on coronary collateral flow after acute occlusion of the left anterior descending coronary artery in dogs. Aspirin dose (600 mg i.v.) consistently inhibited in vitro ADP-induced platelet aggregation. In 13 open-chest dogs, regional myocardial blood flows (radioactive microsphere technique) were determined at 5 minutes and 4 hours after occlusion). In seven of these dogs, aspirin (600 mg i.v.) was administered 1 hour before occlusion. In the aspirin-treated dogs, collateral flow increased significantly (p less than 0.05), from 0.09 +/- 0.02 ml/min/g at 5 minutes to 0.15 and 0.02 ml/min/g 4 hours after occlusion. Collateral flow was not significantly altered over 4 hours in control dogs. The aspirin-induced increase in collateral flo...
Chaotic activity in a mathematical model of the vagally driven sinoatrial node.
Authors: D CMichaels, D RChialvo, E PMatyas, JJalife
Journal: Circulation Research (1989)

Phase-locking behavior and irregular dynamics were studied in a mathematical model of the sinus node driven with repetitive vagal input. The central region of the sinus node was simulated as a 15 x 15 array of resistively coupled pacemakers with each cell randomly assigned one of 10 intrinsic cycle lengths (range 290-390 msec). Coupling of the pacemakers resulted in their mutual entrainment to a common frequency and the emergence of a dominant pacemaker region. Repetitive acetylcholine (ACh; vagal) pulses were applied to a randomly selected 60% of the cells. Over a wide range of stimulus intensities and basic cycle lengths, such perturbations resulted in a large variety of stimulus/response patterns, including phase locking (1:1, 3:2, 2:1, etc.) and irregular (i.e., chaotic) dynamics. At a low ACh concentration (1 microM), the patterns followed the typical Farey sequence of phase-locked behavior. At a higher concentration (5 microM), period doubling and aperiodic patterns were found. When a single pacemak...
Drug-induced conditioning in congestive heart failure.
Authors: C VLeier, PHuss, R PLewis, D VUnverferth
Journal: Circulation (1982)

Continuous 72-hour infusions of dobutamine reportedly effect sustained clinical improvement in patients with congestive heart failure. This study was designed to determine if shorter, more frequent infusions, delivered in an outpatient setting, elicit a similar response. Twenty-six patients with moderately severe congestive heart failure were randomized, 11 into a control group and 15 into a dobutamine treatment group. Baseline data were collected for 4 weeks in each group. Thereafter, the dobutamine treatment group received 4-hour infusions of dobutamine weekly for 24 weeks. Systolic time intervals, echocardiography, cardiac index and treadmill exercise tolerance were used to follow the progress of the control and dobutamine treatment groups. The ratio of preejection period to left ventricular ejection time and the cardiac index did not change significantly in either group. The velocity of circumferential fiber shortening and the percent change in the minor axis of the left ventricle during systole impro...
Acidic fibroblast growth factor and heart development. Role in myocyte proliferation and capillary angiogenesis.
Authors: G LEngelmann, C ADionne, M CJaye
Journal: Circulation Research (1993)

Proliferative growth of the ventricular myocyte (cardiomyocyte) is primarily limited to fetal and early neonatal periods of development. In concert with the neonatal transition from proliferative to hypertrophic growth, ventricular remodeling of the nonmyocyte compartment is characterized by increased extracellular matrix synthesis/deposition and capillary angiogenesis. A role for locally generated and bioactive ventricular acidic fibroblast growth factor (aFGF) in these processes is proposed and substantiated by the following: 1) colocalization of aFGF peptide and fibroblast growth factor receptor (flg) transcripts to the developing fetal cardiomyocyte by immunohistochemistry, immunoelectron microscopy, and in situ hybridization, 2) continued localization of aFGF peptide and transcripts to the neonatal/mature cardiomyocyte, and 3) localization of flg immunoreactivity and transcripts to specific neonatal ventricular nonmuscle cell types. Specific ventricular cell types at distinct developmental stages a...
Dopamine beta-hydroxylase and plasma renin activity in patients with low-, normal-, and high-renin essential hypertension.
Authors: W JLawton, AFitz, CGrant, D LWitte
Journal: Circulation (1979)

The relationship of serum dopamine-beta-hydroxylase (DBH), plasma renin activity (PRA) and urinary catecholamines (IU catechols) in various forms of essential hypertension (EHT) (low, normal and high renin) was evaluated. Eighty-four predominantly white, young (37 +/ 8 years (SD)), mildly hypertensive patients (diastolic pressure 93 +/- 4 mm Hg (SD)) continued their regular diet and received no medications. Thirteen patients had low-renin, 64 had normal-renin, and seven had high-renin EHT. DBH, total IU catechols and urinary norepinephrine were not different between these renin subgroups. DBH was significantly lower in all hypertensives (55.6 +/- 36 IU) and in the low-renin subgroup (46 +/- 30 IU) compared with normal subjects (68 +/- 35 IU) (p less than 0.01). However, the DBH range was so broad that an individual DBH value did not distinguish EHT from normals. After a baseline period, patients were randomly assigned to receive chlorthali done 50 mg q.a.m. or placebo in a double-blind study. In the chlor...
Transthoracic resistance in human defibrillation. Influence of body weight, chest size, serial shocks, paddle size and paddle contact pressure.
Authors: R EKerber, JGrayzel, RHoyt, MMarcus, JKennedy
Journal: Circulation (1981)

Successful defibrillation depends on delivery of adequate electrical current to the heart; one of the major determinants of current flow is transthoracic resistance (TTR). To study the factors influencing TTR, we prospectively collected data from 44 patients undergoing emergency defibrillation. Shocks of 94-450 J delivered energy were administered from specially calibrated Datascope defibrillators that displayed peak current flow, thereby permitting determination of TTR. Shocks were applied from standard (8.5-cm diameter) or large (13 cm) paddles placed anteriorly and laterally. First-shock TTR ranged from 15-143 omega. There was a weak correlation between TTR and body weight (r = 0.45, p less than 0.05) and a stronger correlation between TTR and chest width (r = 0.80, p less than 0.01). Twenty-three patients who were defibrillated using standard 8.5-cm paddles had a mean TTR of 67 +/- 36 omega (+/- SD), whereas 21 patients who received shocks using paddle pairs with at least one large (13 cm) paddle had ...
Vasectomy and Increased Risk of Prostate Cancer
Authors: J. M. H. Ubachs
Journal: JAMA (1993)

<h3>To the Editor.</h3> —Giovannuci et al<sup>1</sup>present strong evidence that vasectomy increases the risk of prostate cancer. They briefly discuss the biologic mechanisms whereby vasectomy may influence that risk, note that there may be a reduction in prostatic secretions after vasectomy, and speculate that this might result in a greater exposure of the gland to carcinogenic factors. In the Editorial on this topic,<sup>2</sup>Drs Howards and Peterson postulate that there are no data to support the hypothesis that the alterations caused by vasectomy will potentiate prostatic cancer. Howards and Peterson indicate that at the moment there is no credible evidence for a possible immunologic mechanism, that the blocking-antibody hypothesis is not currently accepted, and that altered hormone levels are unlikely to play a part. When discussing the question of an eventual biologic mechanism one should be aware that tumor cell growth and blood coagulation are associated. Fibrin formation
Inhibition of prostacyclin and thromboxane A2 generation by low-dose aspirin at the site of plug formation in man in vivo.
Authors: P AKyrle, H GEichler, UJäger, KLechner
Journal: Circulation (1987)

In a double-blind placebo-controlled crossover study, we investigated in seven healthy male volunteers the effect of a low-dose aspirin regimen (35 mg acetylsalicylate per day for 7 days) on the formation of thromboxane A2 (TxA2) and prostacyclin (PGI2) in blood emerging from a standardized injury of the microvasculature made to determine skin bleeding time. When subjects were treated with placebo, there was rapid and substantial generation of TxA2 and PGI2 at the site of platelet-vessel wall interaction within the first 2 min after vascular injury. This was reflected by a greater than 100-fold and greater than 10-fold increase in thromboxane B2 (TxB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) in blood obtained from incisions made to determine bleeding time as compared with the corresponding plasma values. Low-dose aspirin caused a significant inhibition of both TxA2 and PGI2 generation in blood sampled from the skin incisions, represented by a 85% and 92% and 81% and 84% inhibition of TxB2 an...
Drug-induced expansion of infarct: morphologic and functional correlations.
Authors: HHammerman, F JSchoen, EBraunwald, R AKloner
Journal: Circulation (1984)

It has been established that glucocorticoids and several nonsteroidal antiinflammatory drugs, when administered early after coronary occlusion, interfere with myocardial scar formation. To determine whether this action is associated with expansion of myocardial infarct during the first week of coronary occlusion and whether expansion affects ventricular function, the effects of indomethacin on the left ventricle in the early phase of infarction were studied. In a blinded randomized study, experimental myocardial infarction was produced in 17 open-chest dogs by ligation of the proximal left anterior descending coronary artery; the treated group (n = 8) received 10 mg/kg iv indomethacin at 15 min and 3 hr after occlusion, and the control group (n = 9) received saline. After 7 days, regional function expressed as percent change of area (% delta A) of the left ventricular cavity was calculated from short-axis two-dimensional echocardiograms at the level of the infarct, the animals were killed, and their heart...
Macrophage infiltration in acute coronary syndromes. Implications for plaque rupture.
Authors: P RMoreno, EFalk, I FPalacios, J BNewell, VFuster, J TFallon
Journal: Circulation (1994)

BACKGROUNDRupture of atherosclerotic plaques is probably the most important mechanism underlying the sudden onset of acute coronary syndromes. Macrophages may release lytic enzymes that degrade the fibrous cap and therefore produce rupture of the atherosclerotic plaque. This study was designed to quantify macrophage content in coronary plaque tissue from patients with stable and unstable coronary syndromes.METHODS AND RESULTSHematoxylin and eosin and immunostaining with anti-human macrophage monoclonal antibody (PG-M1) were performed. Computerized planimetry was used to analyze 26 atherectomy specimens comprising 524 pieces of tissue from 8 patients with chronic stable angina, 8 patients with unstable angina, and 10 patients with non-Q-wave myocardial infarction. Total plaque area was 417 +/- 87 mm2 x 10(-2) in patients with stable angina, 601 +/- 157 mm2 x 10(-2) in patients with unstable angina, and 499 +/- 87 mm2 x 10(-2) in patients with non-Q-wave myocardial infarction (P = NS). The macrophage-rich a...