tbuckley/cabot-search huggingface dataset:
Metabolic cost of the stimulated beating of isolated adult rat heart cells in suspension.
Authors: R AHaworth, D RHunter, H ABerkoff, R LMoss
Journal: Circulation Research (1983)

Heart cells from adult rats were induced to beat in suspension by electric field stimulation. We have gained evidence that all the rod-shaped cells in suspension were indeed beating, and that the beat had dynamic characteristics similar to those of intact heart muscle contracting under zero load. The cells were undamaged in the process, as judged by maintenance of ATP levels, morphology, and ability to beat. In gaining such evidence, we also measured the metabolic cost to the cells of beating under zero load. In cells with oxidative phosphorylation inhibited by rotenone plus oligomycin (termed anaerobic), the rate of beat-dependent lactate production suggested an equivalent rate of ATP utilization of 0.126 +/- 0.013 nmol ATP/beat per mg protein (plus isoproterenol), and 0.058 +/- 0.005 nmol ATP/beat per mg protein (minus isoproterenol). In respiring cells, the rate of beat-dependent oligomycin-sensitive oxygen consumption gave an equivalent rate of ATP utilization of 0.198 +/- 0.009 nmol ATP/beat per mg p...
Growth of the great vessels in the normal human fetus and in the fetus with cardiac defects.
Authors: P CUrsell, J MByrne, T RFears, B AStrobino, W MGersony
Journal: Circulation (1991)

BACKGROUNDThere is a paucity of quantitative anatomic data regarding human great vessel development that could be useful as a reference for fetal echocardiographers who must distinguish abnormal from normal cardiac development at early stages.METHODS AND RESULTSTo determine normal growth patterns, we plotted the diameters of the aortic and pulmonary valves, ductus arteriosus, aortic isthmus, and descending aorta in 274 autopsy specimens from nonselected spontaneous abortuses of normal karyotype. There was a linear increase in the diameters of these structures within the developmental period studied (10-26 weeks). A relative narrowing of the aorta at the isthmus compared with the aortic valve and descending aorta probably indicates that the majority of fetal left heart output goes to the developing heart and brain. In contrast to previous studies of late gestation and neonatal animals, however, we found that the diameter of the aortic isthmus was larger than that of the ductus arteriosus, suggesting substa...
Mixed-charge pseudo-zwitterionic copolymer brush as broad spectrum antibiofilm coating
Authors: Yang Wu, Cheerlavancha Raju, Zheng Hou, Zhangyong Si, Chen Xu, Dicky Pranantyo, Kalisvar Marimuthu, Partha Pratim De, Oon Tek Ng, Kevin Pethe, En-Tang Kang, Mary B. Chan-Park
Journal: Biomaterials (2021)
Echocardiographic assessment of bicuspid aortic valves. Angiographic and pathological correlates.
Authors: D JRadford, K RBloom, TIzukawa, C AMoes, R DRowe
Journal: Circulation (1976)

Aortic root echocardiograms were recorded from 89 patients whose aortic valves had also been adequately defined by selective angiography or viewed surgically or at autopsy. The eccentricity index (E.I.) of the aortic leaflets was measured at the onset of diastole and an E.I. of 1.3 or greater was taken as abnormal. Of 31 patients with isolated nonobstruced or mildly obstructed bicuspid aortic valves (7 viewed previously at valvotomy and 24 diagnosed radiologically) 23 (74%) had an abnormal E.I. Varying eccentricity occurred in some of these patients. Central leaflet echoes (E.I. of 1.0 to 1.25) were present in the other eight patients. All 14 patients with nonobstructed tricuspid aortic valves had central echoes. Additional multilayered diastolic echoes were found in patients with bicuspid aortic valves as well as in two patients with abnormal tricuspid aortic valves. The valves of 13 patients with aortic stenosis or incompetence were viewed surgically and the E.I. was abnormal in all patients with a bicu...
Diminished inotropic response of aged myocardium to catecholamines.
Authors: E GLakatta, GGerstenblith, C SAngell, N WShock, M LWeisfeldt
Journal: Circulation Research (1975)

The effect of advanced age on the response of active tension, maximal rate of tension development (dT/dt), and contraction duration to catecholamines and to calcium was evaluated in isometric trabeculae carneae from young adult (6-month-old), middle-aged (12-month-old), and aged (25-month-old) rats. Control values were not age dependent except for that for contraction duration which was prolonged in the aged group. At a norepinephrine concentration of 8 times 10-5M, dT/dt increased to 163.8 plus or minus 5.3% of control in the young adult group and to 125.9 plus or minus 6.3% of control in the aged group (P smaller than 0.001). Active tension increased to 121.3 plus or minus 4.0% of control in the young adult muscles but did not increase in the aged muscles (P smaller than 0.01). Contraction duration shortened proportionately in both age groups. Similar results were obtained with isoproterenol. In contrast to the response to catecholamines, there was no age difference in the response of active tension and...
Remodeling of coronary vessels during aging in purebred beagles.
Authors: R JTomanek, M RAydelotte, R JTorry
Journal: Circulation Research (1991)

We compared six young (1 year) and six senescent (11 years) purebred beagles to determine the effects of aging on the coronary microvasculature. The hearts were perfusion-fixed in vitro, and myocardial specimens were subjected to microscopic image analysis. Absolute left ventricular mass increased by 55% with age, while cardiocyte cross-sectional area increased by 10% and 30% in the midmyocardium and endomyocardium, respectively. Although capillary numerical density was lower in the senescent dogs (16% in midmyocardium and 19% in endomyocardium), volume density was similar in the two groups because capillary diameter increased significantly with age in both regions. Capillary length density was reduced by 27% with age in the endomyocardium of the old beagles. Wall/lumen ratios of arterioles of three size classes (less than or equal to 15, 16-25, and 26-50 microns) were found to be nearly identical for the two age groups. Mean arteriolar diameter increased within the smallest size class in both ventricular...
Does normal pump function belie muscle dysfunction in patients with chronic severe mitral regurgitation
Authors: TWisenbaugh
Journal: Circulation (1988)

Left ventricular cineangiography and micromanometry were performed simultaneously in 27 patients with chronic severe mitral regurgitation (MR group) and in 23 normal subjects (NL group). Stress (sigma) and volume (V) were computed frame by frame. Measurements were repeated after pharmacologic load manipulation in subsets of MR (n = 10) and NL (n = 11) groups. An inverse relationship (r = -.90) between EFc (ejection fraction determined from a common preload) and sigma es (afterload) was observed for the NL group. For the MR group, 10 of 14 with EFs less than 0.60 and four of 13 with EFs greater than 0.60 had muscle dysfunction, falling below the 95% prediction band of the normal EFc-sigma es relationship. Maximum myocardial stiffness (maxEN) determined from the end-systolic stress-strain relationship of Mirsky, sigma es = maxEN.gamma.loge(Ves/Vo), was 1398 +/- 716 in the MR (n = 10) vs 1165 +/- 394 in the NL group (n = 11, NS). EF was 0.62 +/- 0.13 in the MR and 0.65 +/- 0.08 in the NL group. Mitral valve ...
Prognosis in patients with low left ventricular ejection fraction after myocardial infarction. Importance of exercise capacity.
Authors: LPilote, JSilberberg, RLisbona, ASniderman
Journal: Circulation (1989)

The measurement of left ventricular ejection fraction (LVEF) plays a key role in many strategies for managing patients after acute myocardial infarction. We tested the hypothesis that exercise capacity 1 month after myocardial infarction provides additional information in patients with a low LVEF and therefore assists in risk stratification. One hundred fifteen patients, with documented myocardial infarction and LVEF less than 35% by gated radionuclide scan 1 month after acute myocardial infarction, were followed up for 2 months to 7 years. Exercise capacity was estimated from a treadmill test 1 month after infarction. Using the Cox proportional hazards model, exercise capacity was a significant predictor of death or reinfarction. The relative risk of death, based on a comparison between the lowermost quintile (less than 4 METS) and uppermost quintile (greater than 7 METS), was 3.5 (95% confidence interval, 1.1-9.7); the relative risk in the fourth, third, and second quintile was 2.7, 2.1, and 1.6, respec...
Contribution of cAMP-phosphodiesterase inhibition and sensitization of the contractile proteins for calcium to the inotropic effect of pimobendan in the failing human myocardium.
Authors: MBöhm, IMorano, BPieske, J CRüegg, MWankerl, RZimmermann, EErdmann
Journal: Circulation Research (1991)

Previous studies have shown reduced effects of cAMP-dependent positive inotropic agents in the failing human myocardium; thus other cAMP-independent mechanisms of action may be useful to increase force of contraction in this condition. The purpose of this investigation was to determine whether a positive inotropic effect of the cAMP-phosphodiesterase (PDE) inhibitor pimobendan is observed in the failing human myocardium and to study whether other factors, such as an increase in the Ca2+ sensitivity of myofilaments, play a functional role in the increase in force of contraction. Pimobendan produced a positive inotropic effect in isolated preparations from nonfailing donor hearts; however, in moderately (New York Heart Association class II-III, NYHA II-III) and severely (NYHA IV) failing myocardium, this effect was reduced. In addition, in NYHA IV specimens pimobendan inhibited the crude cAMP-PDE (crude PDE) and the isoenzymes I-III (PDE I-III) in a concentration-dependent way. As judged from the IC50 value...
A Perspective on Hospice Reform and Additional Caregiver Support—Reply
Authors: Joan M. Teno, Michael R. Plotzke
Journal: JAMA Internal Medicine (2016)

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 Internal Medicine 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 Internal Medicine journal
Effect of the sympathetic nervous system on limb circulation and metabolism during exercise in patients with heart failure.
Authors: J RWilson, NFerraro, D HWiener
Journal: Circulation (1985)

During exercise in patients with heart failure, activation of sympathetic vasoconstrictor nerves may impair vasodilation in active skeletal muscle and thereby interfere with skeletal muscle blood flow. To investigate this hypothesis, we examined the effect of acute alpha-adrenergic blockade with systemic administration of prazosin (10 patients) or regional administration of phentolamine (eight patients) on blood flow, vascular resistance, oxygen consumption (VO2), and lactate release in the leg during maximal bicycle exercise in patients with heart failure. During control exercise, systemic VO2 increased to 12.6 +/- 4.3 ml/min/kg (normal greater than 20 to 25 ml/min/kg), leg blood flow to 2.8 +/- 1.8 liters/min, and leg lactate release to 362 +/- 256 mg/min. Prazosin decreased systemic vascular resistance (12.5 +/- 3.2 to 9.7 +/- 2.5 units; p less than .003) and mean arterial pressure (101 +/- 20 to 87 +/- 22 mm Hg; p less than .002) at maximal exercise, supporting the presence of substantial sympathetic ...
Electrogram criteria for identification of appropriate target sites for radiofrequency catheter ablation of accessory atrioventricular connections.
Authors: HCalkins, Y NKim, SSchmaltz, JSousa, Rel-Atassi, ALeon, AKadish, J JLangberg, FMorady
Journal: Circulation (1992)

BACKGROUNDCatheter ablation of accessory atrioventricular (AV) connections using radiofrequency current has been demonstrated to be effective in the majority of patients with the Wolff-Parkinson-White syndrome or paroxysmal supraventricular tachycardia involving a concealed accessory AV connection. However, electrogram criteria have not been established to guide attempts at radiofrequency catheter ablation.METHODS AND RESULTSThe characteristics of local electrograms recorded at successful and unsuccessful sites of radiofrequency catheter ablation were determined in 132 patients. Electrograms recorded at a total of 438 sites were analyzed: 338 recorded during ablation of 90 manifest accessory AV connections and 100 recorded during ablation of 44 concealed accessory AV connections. During ablation of manifest accessory AV connections, the independent predictors of outcome were electrogram stability (p less than 0.001), the interval between activation of the ventricular electrogram and onset of the QRS compl...
Ultraviolet A radiation and COVID‐19 deaths in the USA with replication studies in England and Italy*
Authors: M. Cherrie, T. Clemens, C. Colandrea, Z. Feng, D.J. Webb, R.B. Weller, C. Dibben
Journal: British Journal of Dermatology (2021)

Understanding factors impacting deaths from COVID-19 is of the highest priority. Seasonal variation in environmental meteorological conditions affects the incidence of many infectious diseases and may also affect COVID-19. Ultraviolet (UV) A (UVA) radiation induces release of cutaneous photolabile nitric oxide (NO) impacting the cardiovascular system and metabolic syndrome, both COVID-19 risk factors. NO also inhibits the replication of SARS-CoV2.To investigate the relationship between ambient UVA radiation and COVID-19 deaths.COVID-19 deaths at the county level, across the USA, were modelled in a zero-inflated negative-binomial model with a random effect for states adjusting for confounding by demographic, socioeconomic and long-term environmental variables. Only those areas where UVB was too low to induce significant cutaneous vitamin D3 synthesis were modelled. We used satellite-derived estimates of UVA, UVB and temperature and relative humidity. Replication models were undertaken using comparable data for England and Italy.The mortality rate ratio (MRR) in the USA falls by 29% [95% confidence interval (CI) 40% to 15%) per 100 kJ m-2 increase in mean daily UVA. We replicated this in independent studies in Italy and England and estimate a pooled decline in MRR of 32% (95% CI 48% to 12%) per 100 kJ m-2 across the three studies.Our analysis suggests that higher ambient UVA exposure is associated with lower COVID-19-specific mortality. Further research on the mechanism may indicate novel treatments. Optimized UVA exposure may have population health benefits.
Smoothened Stabilizes and Protects TRAF6 from Proteosomal Degradation: A Novel Non-Canonical Role of Smoothened with Implications in Lymphoma Biology
Authors: Changju QU, Amineh Vaghefi, Kranthi Kunkalla, Jennifer R Chapman, Yadong Liu, Marzenna Blonska, Juan Pablo Alderuccio, Leon Bernal-Mizrachi, Izidore S Lossos, Ralf Landgraf, Francisco Vega
Journal: Blood (2017)
Late potentials and ventricular enlargement after myocardial infarction. A new role for high-resolution electrocardiography?
Authors: A GZaman, J LMorris, J HSmyllie, J CCowan
Journal: Circulation (1993)

BACKGROUNDArrhythmias are common in patients who have developed ventricular enlargement after myocardial infarction.METHODS AND RESULTSA prospective study was undertaken to assess the relation between ventricular dilatation and the development of late potentials after myocardial infarction. Echocardiograms and signal-averaged ECGs were recorded on days 1,3,7, and 42 in 52 patients with a first anterior myocardial infarction. Twenty-nine percent of patients were late potential-positive on their initial signal-averaged ECG recorded on the day of admission. The incidence of late potentials rose during the next week to a peak of 42% at day 7, declining to 13% by day 42. The presence of late potentials on the day of admission was associated with an increase in end-diastolic volume index of 16.1 +/- 6.0 mL/m2 (mean +/- SEM), compared with a decreased of 4.7 +/- 2.7 mL/m2 among late potential-negative patients (P < .006). Qualitatively similar results were evident for late potentials on day 3 and day 7. By contr...
Eﬃcient drug delivery and anticancer eﬀect of micelles based on vitamin E succinate and chitosan derivatives
Authors: Xiaotong Chen, Junxiang Gu, Le Sun, Wenya Li, Lili Guo, Zhiyang Gu, Litong Wang, Yan Zhang, Wangwang Zhang, Baoqin Han, Jing Chang
Journal: Bioactive Materials (2021)

Nanocarriers have emerged as a promising cancer drug delivery strategy. Multi-drug resistance caused by overexpression of multiple-drug excretion transporters in tumor cells is the major obstacle to successful chemotherapy. Vitamin E derivatives have many essential functions for drug delivery applications, such as biological components that are hydrophobic, stable, water-soluble enhancing compounds, and anticancer activity. In addition, vitamin E derivatives are also effective mitocan which can overcome multi-drug resistance by binding to P glycoproteins. Here, we developed a carboxymethyl chitosan/vitamin E succinate nano-micellar system (O-CMCTS-VES). The synthesized polymers were characterized by Fourier Transform IR, and 1H NMR spectra. The mean sizes of O-CMCTS-VES and DOX-loaded nanoparticles were around 177 nm and 208 nm. The drug loading contents were 6.1%, 13.0% and 10.6% with the weight ratio of DOX to O-CMCTS-VES corresponding 1:10, 2:10 and 3:10, and the corresponding EEs were 64.3%, 74.5% and 39.7%. Cytotoxicity test, hemolysis test and histocompatibility test showed that it had good biocompatibility in vitro and in vivo. Drug release experiments implied good pH sensitivity and sustained-release effect. The DOX/O-CMCTS-VES nanoparticles can be efficiently taken up by HepG2 cancer cells and the tumor inhibition rate is up to 62.57%. In the in vivo study by using H22 cells implanted Balb/C mice, DOX/O-CMCTS-VES reduced the tumor volume and weight efficiently with a TIR of 35.58%. The newly developed polymeric micelles could successfully be utilized as a nanocarrier system for hydrophobic chemotherapeutic agents for the treatment of solid tumors.
Correlation of postmortem anatomic findings with electrocardiographic changes in patients with myocardial infarction: retrospective study of patients with typical anterior and posterior infarcts.
Authors: R MSavage, G SWagner, R EIdeker, S APodolsky, D BHackel
Journal: Circulation (1977)

This retrospective study correlates electrocardiographic and histopathologic findings in 24 patients with single well-circumscribed infarcts to determine 1) whether ECG terms commonly used to describe the location of myocardial infarcts are significant, and 2) whether the extent of infarct can be determined using QRS characteristics. Transverse sections of the hearts were photographed. Based on histologic sections, the infarct was outlined on the photograph and each section was planimetered via a sonic digitizer into a computer that was programmed to divide the left ventricle into 8 radial sectors and also into basal, mesial, and apical thirds. The percentage of infarct in each of these areas was then calculated. Of the 24 hearts evaluated 12 had posterior infarcts and 12 had anterior infarcts. Posterior infarcts principally involved the basal and mesial levels, whereas the anterior infarcts were more extensive in the apical and mesial thirds, with relative or total sparing of the base. Posterior infarcts...
Modulation of Cytokine Production and Protection Against Lethal Endotoxemia by the Cardiac Glycoside Ouabain
Authors: AkiraMatsumori, KohOno, RyosukeNishio, HidekiIgata, BPharm, TetsuoShioi, ShigeoMatsui, YutakaFurukawa, AtsushiIwasaki, YoshisukeNose, ShigetakeSasayama
Journal: Circulation (1997)

Background Recent studies have shown that cytokines are capable of modulating cardiovascular function and that some drugs used in the treatment of heart failure variably modulate the production of cytokines. To examine whether cardiac glycosides also modulate cytokine production, we evaluated the effects of ouabain on the production of cytokines in vitro and in vivo. Methods and Results Human peripheral blood mononuclear cells (PBMC) were obtained from healthy volunteers. PBMC were cultured with or without ouabain in the presence or absence of lipopolysaccharide (LPS). Ouabain induced the production of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α in PBMC and induced mRNA of these cytokines, an induction apparently at the transcriptional level. Amiloride, staurosporin, and genistein inhibited cytokine production, and protein kinase C and tyrosine kinase appeared to be involved in the modulation of cytokine production induced by ouabain. However, when PBMC were stimulated with LPS, ouabain s...
Shall The Journal be Removed to Washington?
Authors: G. W. McCaskey
Journal: JAMA (1891)

To the Editor:  —I have watched with considerable interest the lengthy and numerous discussions which have been presented in your columns in regard to the proposed removal ofThe Journalto Washington. I cannot see wherein any advantage whatever would accrue toThe Journalby such a change in its location. The American Medical Association is not a sectional body; or if it is open to the charge of sectionalism at all, as some may maintain, it certainly is not an Eastern organization. The greatest loyalty to its integrity, honor and development, cannot be claimed by the medical profession of the States East of the Alleghany mountains, as a body. This remark is not intended to reflect in the least upon the illustrious services of a large mumber of Eastern physicians without whose cooperation the American Medical Association would not be what it is to-day. Nevertheless the fact as stated
Glycemic And Hepatic Outcomes After Endoscopic Duodenal Mucosal Resurfacing: A Systematic Review And Meta-Analysis
Authors: GHP de Oliveira, DTH de Moura, TR McCarty, MP Funari, IB Ribeiro, VMT Sagae, WM Bernardes, JR Freitas Junior, GMV Souza, EGH Moura
Journal: Endoscopy (2021)

Aims Duodenal mucosal resurfacing (DMR) is a groundbreaking endoscopic bariatric and metabolic therapy (EBMT). It is an upper endoscopic procedure that, using a catheter, performs mucosal ablation in postpapillary duodenum to achieve better glycemic control. This study aimed to evaluate the glycemic and hepatic effects of this new procedure.