tbuckley/cabot-search huggingface dataset:
Mitral prosthesis malfunction. Comparative Doppler echocardiographic studies of mitral prostheses before and after replacement.
Authors: UNellessen, TMasuyama, C PAppleton, TTye, R LPopp
Journal: Circulation (1989)

To assess the influence of mitral prosthesis malfunction on various Doppler echocardiographic indexes, we studied the changes in the peak mitral flow velocity during early diastolic filling phase (Vmax), the mean transprosthesis pressure drop from the simplified Bernoulli equation, the mitral valve area by the pressure half-time method, and the left ventricular isovolumic relaxation time in 15 patients before and after replacement of the malfunctioning mitral prosthesis using continuous wave Doppler echocardiography. Examination of the 15 replaced prostheses revealed a torn or perforated leaflet in 12 valves and a sewing ring dehiscence in one valve. Additional restricted leaflet motion (classified as mild obstruction) was seen in three of these 13 valves. In the remaining two valves, severe prosthesis obstruction was noted. Changes in the Doppler indexes between the preoperative and postoperative study were present in all patients regarding Vmax (mean, 2.2 +/- 0.3 versus 1.6 +/- 0.2 m/sec; p less than 0....
Long-term results of dual-chamber (DDD) pacing in obstructive hypertrophic cardiomyopathy. Evidence for progressive symptomatic and hemodynamic improvement and reduction of left ventricular hypertrophy.
Authors: LFananapazir, N DEpstein, R VCuriel, J APanza, DTripodi, DMcAreavey
Journal: Circulation (1994)

BACKGROUNDWe previously reported that 6 to 12 weeks of dual-chamber (DDD) pacing results in clinical and hemodynamic improvement in obstructive hypertrophic cardiomyopathy (HCM). This study examines the long-term results of DDD pacing in obstructive HCM.METHODS AND RESULTSDDD devices were implanted in 84 patients (mean age, 49 +/- 16 years) with obstructive HCM and severe drug-refractory symptoms. At a mean follow-up of 2.3 +/- 0.8 years (maximum, 3.5 years), the New York Heart Association (NYHA) functional class had improved significantly (1.6 +/- 0.6 versus 3.2 +/- 0.5, P < .00001). Symptoms were eliminated in 28 patients (33%), improved in 47 patients (56%), but remained unchanged in 7 patients (8%). Two patients died suddenly (97% cumulative 3-year survival rate). In 74 patients with significant left ventricular outflow tract (LVOT) obstruction at rest, the LVOT gradients were significantly reduced at follow-up (27 +/- 31 versus 96 +/- 41 mm Hg, P < .00001). Symptoms and provokable LVOT gradients were...
Lehrbuch der Augenheilkunde.
Journal: JAMA (1923)

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 HomeNew OnlineCurrent IssueFor Authors 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) Podcasts Clinical Reviews Editors' Summary Medical News Author Interviews More 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 journal
Acute renovascular hypertension in conscious dogs. Interaction of the renin-angiotensin system and sympathetic nervous system in systemic hemodynamics and regional blood flow responses.
Authors: HGavras, CLiang
Journal: Circulation Research (1980)

The effects of acute renovascular hypertension on the sympathetic nervous system, regional blood flow and cardiac function were studied in conscious dogs submitted to renal artery occlusion by inflation of a cuff implanted previously around one renal artery. We then compared the alterations in plasma renin and catecholamine levels and in the various hemodynamic parameters induced by those maneuvers in intact dogs, to those in dogs pretreated with alpha- and beta-adrenergic receptor blockers. Subsequently, the converting enzyme inhibitor teprotide was administered to inhibit angiotensin formation in both experiments. Our results suggest that both the renin-angiotensin system and the sympathetic system contribute to the rise in blood pressure. The hemodynamic changes and alterations in regional blood flows accompanying this acute hypertension appear to be due mostly to the increase in plasma angiotensin, since prior adrenoceptor blockade only attenuated their magnitude but did not alter their direction. How...
Regional edema formation in isolated perfused dog lungs.
Authors: C AHales, D JKanarek, BAhluwalia, ALatty, JErdmann, SJavaheri, HKazemi
Journal: Circulation Research (1981)

Studies using gravimetric analysis of lungs of frozen animals have suggested that the differences in pulmonary microvascular pressure between non-dependent and dependent lung do not influence the formation of regional pulmonary edema. We wondered if the inability to detect variation in regional extravascular lung water (EVLW) was due to the slow freezing process and, therefore, reassessed the distribution of EVLW in vertically suspended isolated perfused dog lungs with a radioisotopic technique that does not require freezing. Total lung water (TLW), blood or intravascular lung water (IVLW), and EVLW were measured in absolute quantities using a positron camera and the positron-emitting isotopes C15O as a blood label and H2(15)O as a total lung water label. Mean isotopic TLW in 17 lungs that were normal or moderately edematous (wet:dry ratio < 7) was 142 +/- 9 (SE) ml compared to the gravimetric estimate of 148 +/- 7 ml (r = 0.92) and isotopic EVLW was 64 +/- 6 ml compared to the gravimetric estimate of 70 ...
Pressure-flow characteristics of the coronary collateral circulation during cardiopulmonary bypass. Effects of ventricualr fibrillation.
Authors: L HKleinman, A SWechsler
Journal: Circulation (1978)

Even though ventricular fibrillation is used frequently during cardiopulmonary bypass (CPB), the effects of fibrillation on myocardial regions supplied by collateral vessels have not been determined. To study these effects, nine dogs with left ventricles (ameroid model) consisting of a region of myocardium supplied by collateral vessels (CR) and a region supplied by normal coronary arteries (NR) were subjected to normothermic CPB at two perfusion pressures. In both the empty beating heart (EBH) and empty fibrillating heart (EFH) regional myocardial flow was determined by tracer microspheres. Retrograde coronary pressure was measured via cannulation of the circumflex artery distal to the ameroid induced occlusion. When perfusion pressure was maintained at 80 mm Hg, retrograde coronary pressure was similar in the EBH (46 +/- 4 mm Hg) and in the EFH (48 +/- 3 mm Hg). During fibrillation subendocardial flow in the CR was unchanged, while flow in the NR increased (P less than 0.02). In addition, the endo/epi w...
Electrophysiologic studies in patients with ventricular inversion and "corrected transposition".
Authors: P CGillette, UBusch, C EMullins, D GMcNamara
Journal: Circulation (1979)

We evaluated the intracardiac conduction intervals using His bundle recordings in 40 patients with ventricular inversion and 1-transposition of the great arteries. Twenty-nine subjects had 1:1 atrioventricular (AV) conduction. In 15 of those with normal PR intervals and QRS durations, the conduction intervals were not different from those of subjects with normal hearts. In the 14 patients with first-degree AV block, the block was located between the sinus node and AV node in four, between the low right atrium and bundle of His in seven, and below the common bundle of His in four. In 11 subjects with complete AV block, the stie of block was above the site of the His potential in four, below in two and within the His bundle in one. In four patients we could not record a His potential and thus could not localize the site of block. Complete block below the His recording site was associated with syncope in one patient and sudden death in another. His bundle recording is a safe technique for studying the conduc...
Dynamics of normal and ischemic canine papillary muscles.
Authors: S CRayhill, G TDaughters, L JCastro, M ANiczyporuk, M RMoon, N BIngels, M LStadius, G CDerby, A FBolger, D CMiller
Journal: Circulation Research (1994)

This investigation was designed to elucidate the dynamics of the left ventricular (LV) papillary muscles. Miniature tantalum myocardial markers were placed on the tip and base of each papillary muscle in six dogs. Markers were also implanted into the LV myocardium to define two orthogonal equatorial diameters and the long-axis dimension. Two weeks later, after recovery from thoracotomy, markers were visualized by biplane fluoroscopy, and video images were recorded during control conditions, after autonomic blockade, after inotropic stimulation with calcium, after methoxamine infusion (to increase afterload), and after blood volume augmentation (to increase preload). Two days later, radiographic recordings were made before and after occlusion of the left circumflex coronary artery. Computer-aided analysis of the video recordings was used to determine three-dimensional coordinates of the markers. It was found that before circumflex coronary occlusion, the dynamics of both papillary muscles closely mimicked ...
The Challenge of Staging Breast Cancer With PET/CT in the Era of COVID Vaccination
Authors: Adam Harry Brown, Sweni Shah, Ashley M. Groves, Simon Wan, Anmol Malhotra
Journal: Clinical Nuclear Medicine (2021)

Abstract We report a case series of biopsy-proven reactive axillary lymph nodes, which were avid on FDG PET/CT in breast cancer patients post COVID-19 vaccination. With 4 cases presenting in a consecutive 10-day period, it became apparent that metabolically active axillary lymphadenopathy is an adverse effect of COVID-19 vaccines, currently being deployed worldwide. This may lead to patients undergoing unnecessary biopsy. We have started taking a COVID-19 vaccine status history before PET/CT. If enlarged/metabolically active axillary nodes are identified in the ipsilateral vaccinated arm, then axillary ultrasound at 4 weeks is suggested.
Disruption of myofibrillar energy use: dual mechanisms that may contribute to postischemic dysfunction in stunned myocardium.
Authors: R AGreenfield, J LSwain
Journal: Circulation Research (1987)

The abnormalities in regional function produced by myocardial ischemia persist after the ischemic episode resolves. Since a close functional coupling exists between myofibrillar creatine kinase and myosin ATPase, a disruption of this coupling could adversely influence myocardial function and might provide a mechanism for the myocardial dysfunction observed. The purpose of the present study was to determine if an alteration in the activity of creatine kinase associated with the myofibril occurs in the postischemic period. Anesthetized open-chest dogs (n = 6) underwent coronary occlusion for 15 minutes, followed by reperfusion for 15 minutes. In reperfused myocardium, adenine nucleotide content was decreased (72 +/- 10% of nonischemic myocardium, p less than 0.05), documenting the presence of previous ischemia. The creatine phosphate content of reperfused myocardium returned to normal, indicating resumption of myocardial energy production. The creatine kinase activity of purified myofibrils isolated from re...
Inotropic effect, binding properties, and calcium flux effects of the calcium channel agonist CGP 28392 in intact cultured embryonic chick ventricular cells.
Authors: SLaurent, DKim, T WSmith, J DMarsh
Journal: Circulation Research (1985)

CGP 28392 is a recently described dihydropyridine derivative with positive inotropic properties. To study the mechanism of action of this putative calcium channel agonist, we have related the effects of CGP 28392 on contraction (measured with an optical video system) and radioactive calcium uptake to ligand-binding studies in cultured, spontaneously beating chick embryo ventricular cells. CGP 28392 produced a concentration-dependent increase in amplitude and velocity of contraction (EC50 = 2 X 10(-7) M; maximum contractile effect = 85% of the calcium 3.6 mM response). Nifedipine produced a shift to the right of the concentration-effect curve for CGP 28392 without decreasing the maximum contractile response, suggesting competitive antagonism (pA2 = 8.3). Computer analysis of displacement of [3H]nitrendipine binding to intact heart cells by unlabeled CGP 28392 indicated a KD = 2.2 +/- 0.95 X 10(-7) M, in good agreement with the EC50 for the inotropic effect. CGP 28392 increased the rate of radioactive calci...
Heart rate and force-frequency effects on diastolic function of the left ventricle in exercising dogs.
Authors: TMiura, SMiyazaki, B DGuth, CIndolfi, JRoss
Journal: Circulation (1994)

BACKGROUNDPrevious studies from our laboratory have shown pronounced augmentation of the force-frequency relation on myocardial contraction during exercise, but the influence of this effect on diastole has not been investigated.METHODS AND RESULTSAccordingly, the effect of changing heart rate on left ventricular (LV) relaxation, filling dynamics, and pressure-volume relations during exercise was studied in eight conscious dogs. The exercise heart rate was slowed from 208 +/- 21 (SD) to 163 +/- 11 beats per minute by injection of a specific sinus node inhibitor (UL-FS 49, or zatebradine, 0.6 mg/kg) during continuous exercise. Heart rate was then abruptly restored to the predrug level by atrial pacing during continued exercise. LV volume was calculated by use of implanted ultrasonic crystals, and LV pressure was determine with an implanted micromanometer. Comparing conditions after pacing back to a heart rate of 210 beats per minute with those obtained when the heart rate was slowed by atrial pacing, LV dP/...
RE: BRCA2 Polymorphic Stop Codon K3326X and the Risk of Breast, Prostate, and Ovarian Cancers Response
Authors: A.B. Spurdle, S. Domchek, M. Robson, S. Buys, P. Radice, M. de la Hoya, P. Devilee, A.N.A. Monteiro, M. Southey, D. Eccles, F.J. Couch, D.E. Goldgar
Journal: JNCI Journal of the National Cancer Institute (2016)
Coronary collateral function during exercise.
Authors: CEng, R EPatterson, S FHorowitz, D AHalgash, A DPichard, JMidwall, M VHerman, RGorlin
Journal: Circulation (1982)

A totally occluded coronary vessel subtending a noninfarcted, entirely collateral-dependent myocardial region (NIECDMR) provides an opportunity to assess collateral perfusion during exercise stress. Collateral function was determined by analysis of exercise thallium-201 myocardial perfusion images from 31 patients who had at least one NIECDMR (total 41 NIECDMRs) documented during catheterization. Twenty-two of 41 NIECDMRs manifested exercise-induced perfusion defects and 19 were normally perfused. The exercise-negative NIECDMRs were further categorized: Group 1 NIECDMRs (n = 13) were associated with defects in other myocardial regions supplied by diseased vessels and were considered negative relative to other jeopardized regions; group 2 NIECDMRs (n = 6) were not associated with exercise-induced defects in other myocardial regions, which suggests that collateral perfusion was adequate during maximal exercise. Regions supplied by a diseased left anterior descending coronary artery manifested exercise defec...
Debates Around the Role of School Closures in the Coronavirus 2019 Pandemic
Authors: Shuliang Oliver Cheng, Aurelia Liu
Journal: JAMA Pediatrics (2020)

To the Editor: We read with great interest the article by Esposito and Principi, 1 who expressed skepticism as to whether school closure is an effective measure in mitigating the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).It was interesting to read that Taiwan successfully slowed the spread of SARS-CoV-2 without school closure.Additionally, they highlighted that school closure had no significant effect on the spread of SARS-CoV-2 in China.Other countries, such Japan, Israel, Denmark, and Norway, also closed their schools in an attempt to mitigate the spread of SARS-CoV-2.Interestingly, Denmark and Norway reopened their schools in April 2020 and have continued to see a decline in the number of new infections as of May 2020. 2 Denmark was one of the first countries to close schools and enforced school closure on March 11, 2020, with 262 confirmed coronavirus cases.After several weeks of closure, the Danish government reopened schools for young children on April 15, 2020. 2 In this period, the number of cases rose by 6249 to 6511 cases over a period of 35 days.As of May 25, 2020, the number of cases in Denmark stands at 11 360, a rise of 4849 cases in 40 days. 3 Thus, in a longer period with schools reopened, Denmark has seen fewer new cases of SARS-CoV-2 infection than when schools were closed.Norway was another country to close all educational institutions early, doing so on March 12, 2020, with 489 total confirmed cases. 3,4 Norway began reopening kindergartens on April 20, 2020, and junior schools on April 27. 5 Between March 12 and April 27, there was a rise of 7016 cases to a total of 7505.Since reopening primary schools, there have been just 804 new cases in Norway between April 27, 2020, and May 25, 2020, over 29 days. 3 As in Denmark, Norway has seen a huge decrease in the number of new cases while schools reopen.The reopening of schools is extremely important because children depend on schools for normal social and intellectual development.The decrease in new cases in Denmark and Norway as their schools reopen is a very encouraging sign.However, it would be nonetheless prudent to continuously monitor the number of new cases as schools reopen across the world.
Effect of age on blood pressure and membrane-dependent vascular responses in the rat.
Authors: E ESoltis
Journal: Circulation Research (1987)

Alterations in endothelium-dependent, sodium pump-mediated, and calcium-dependent responses of vascular smooth muscle were investigated in 5-7-, 24-26-, and 50-52-week-old male Sprague-Dawley rats. Age-dependent changes in systolic blood pressure were also determined. Although systolic blood pressure increased significantly with age, rats in all 3 age groups were considered normotensive. Initial studies on the passive force-response characteristics of strips of aortic and femoral arterial smooth muscle revealed that the level of passive force required for maximum active tension generation increased with increasing age. Subsequent studies were carried out using optimum passive force requirements. Endothelium-dependent relaxations of aortic smooth muscle induced by acetylcholine and the calcium ionophore A23187 decreased significantly with increasing age. An age-dependent decrease in the contractile response of aortic smooth muscle to ouabain and potassium-free physiological salt solution (PSS) was observed...
Effect of chronic rapid ventricular pacing on total vascular capacitance.
Authors: R IOgilvie, DZborowska-Sluis
Journal: Circulation (1992)

BACKGROUNDRapid right ventricular pacing (RRVP) at 250 bpm for 3-6 weeks produces chronic heart failure manifested by a reduction in cardiac output and increases in right atrial, pulmonary artery, and capillary wedge pressures.METHODS AND RESULTSOne week after splenectomy and pacemaker placement, vascular capacitance, unstressed volume, and compliance were determined in 19 anesthetized dogs from pressure-volume curves using transient circulatory arrests induced by acetylcholine. Nine dogs were restudied 31 +/- 1 days later without RRVP, and 10 dogs underwent RRVP at 250 bpm and were restudied at 23 +/- 8 and 38 +/- 8 days in cardiac failure and after 1 and 2 weeks of postpacing recovery. Control animals had no changes in vascular capacitance or compliance. Dogs undergoing RRVP exhibited a marked increase in mean circulatory filling pressure (5.4 +/- 0.4 to 10.5 +/- 1.5 mm Hg) during the development of cardiac failure with a reduction in unstressed volume (81.9 +/- 5.7 to 43.9 +/- 8.1 ml.kg-1) without chan...
Avelumab in Combination with Axitinib as First-Line Treatment in Patients with Advanced Hepatocellular Carcinoma: Results from the Phase 1b VEGF Liver 100 Trial
Authors: Masatoshi Kudo, Kenta Motomura, Yoshiyuki Wada, Yoshitaka Inaba, Yasunari Sakamoto, Masayuki Kurosaki, Yoshiko Umeyama, Yoichi Kamei, Junichiro Yoshimitsu, Yosuke Fujii, Mana Aizawa, Paul B. Robbins, Junji Furuse
Journal: Liver Cancer (2021)

Combining an immune checkpoint inhibitor with a targeted antiangiogenic agent may leverage complementary mechanisms of action for the treatment of advanced/metastatic hepatocellular carcinoma (aHCC). Avelumab is a human anti-PD-L1 IgG1 antibody with clinical activity in various tumor types; axitinib is a selective tyrosine kinase inhibitor of vascular endothelial growth factor receptors 1, 2, and 3. We report the final analysis from VEGF Liver 100 (NCT03289533), a phase 1b study evaluating safety and efficacy of avelumab plus axitinib in treatment-naive patients with aHCC.Eligible patients had confirmed aHCC, no prior systemic therapy, ≥1 measurable lesion, Eastern Cooperative Oncology Group performance status ≤1, and Child-Pugh class A disease. Patients received avelumab 10 mg/kg intravenously every 2 weeks plus axitinib 5 mg orally twice daily until progression, unacceptable toxicity, or withdrawal. Endpoints included safety and investigator-assessed objective response per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 and modified RECIST (mRECIST) for HCC.Twenty-two Japanese patients were enrolled and treated with avelumab plus axitinib. The minimum follow-up was 18 months as of October 25, 2019 (data cutoff). Grade 3 treatment-related adverse events (TRAEs) occurred in 16 patients (72.7%); the most common (≥3 patients) were hypertension (n = 11 [50.0%]), palmar-plantar erythrodysesthesia syndrome (n = 5 [22.7%]), and decreased appetite (n = 3 [13.6%]). No grade 4 TRAEs or treatment-related deaths occurred. Ten patients (45.5%) had an immune-related AE (irAE) of any grade; 3 patients (13.6%) had an infusion-related reaction (IRR) of any grade, and no grade ≥3 irAE and IRR were observed. The objective response rate was 13.6% (95% CI: 2.9-34.9%) per RECIST 1.1 and 31.8% (95% CI: 13.9-54.9%) per mRECIST for HCC.Treatment with avelumab plus axitinib was associated with a manageable toxicity profile and showed antitumor activity in patients with aHCC.
Isozyme specific modification of myosin ATPase by cAMP in rat heart.
Authors: SWinegrad, AWeisberg
Journal: Circulation Research (1987)

The total ATPase activity of myosin and the values for the isozyme V1 have been measured in hearts from rats of different ages and with different levels of thyroid function. The contribution of V3 was calculated from the difference between total and V1 ATPase, neglecting the small contribution of V2. Hearts were quickly frozen after rapid removal from the animals in order to preserve the state of ATPase activity that existed in the intact animal, and ATPase activity was measured in thin sections of tissue by a microphotometric technique. In euthyroid hearts, although cAMP increases total myosin ATPase activity and the activity of V1, the cyclic nucleotide inhibits the ATPase activity of V3. In hearts from rats with developing hypothyroidism following thyroidectomy, the same occurs. After a sufficient period has elapsed after thyroidectomy for V1 to have practically disappeared, cAMP has no effect on ATPase activity, but the injection of thyroid hormone restores the effect. Total myosin ATPase activity is ...