tbuckley/cabot-search huggingface dataset:
Negative feedback regulation of endothelial cell function by nitric oxide.
Authors: G MBuga, J MGriscavage, N ERogers, L JIgnarro
Journal: Circulation Research (1993)

The objective of this study was to determine whether nitric oxide (NO) could function as a negative feedback modulator of endothelial cell function by inhibiting NO synthase in vascular endothelial cells. The rationale for this approach was a previous study from this laboratory, which revealed that NO inhibits neuronal NO synthase from rat cerebellum. In the present study, NO and NO-donor agents noncompetitively inhibited NO synthase derived from bovine aortic endothelial cells. Oxyhemoglobin blocked the inhibitory action of NO and by itself increased NO synthase activity. This finding suggests that NO acts as a negative feedback modulator of NO synthase. In intact aortic endothelial cells grown on microcarrier beads and perfused in a bioassay cascade system, pretreatment of cells with NO-donor agents caused a marked inhibition of endothelial NO biosynthesis in response to bradykinin and increased fluid shear or flow. When isolated bovine pulmonary arterial rings precontracted by phenylephrine were used, ...
Noninvasive method for determination of arterial compliance using Doppler echocardiography and subclavian pulse tracings. Validation and clinical application of a physiological model of the circulation.
Authors: R HMarcus, CKorcarz, GMcCray, ANeumann, MMurphy, KBorow, LWeinert, JBednarz, D DGretler, K TSpencer
Journal: Circulation (1994)

BACKGROUNDThe Poiseuillian model of the arterial system currently applied in clinical physiology does not explain how arterial pressure is maintained during diastole after cessation of pulsatile aortic inflow. Arterial pressure-flow relations can be more accurately described by models that incorporate arterial viscoelastic properties such as arterial compliance. Continuous pressure and flow measurements are needed to evaluate these properties. Since the techniques used to date to acquire such data have been invasive, physiological models of the circulation that incorporate these properties have not been widely applied in the clinical setting. The purpose of this study was (1) to validate noninvasive methods for continuous measurement of central arterial pressure and flow and (2) to determine normal reference values for arterial compliance using physiological models of the circulation applied to the noninvasively acquired pressure and flow data.METHODS AND RESULTSSimultaneously acquired invasive and noninv...
Predictors of Precut Techniques Requirement During ERCP Cannulation
Authors: N Zaragoza, M Alburquerque, I Miguel, M Figa, E Pijoan, JM Miñana, A Vargas, G Torres, JM Reñe, F González-Huix
Journal: Endoscopy (2021)

Corrected by:Predictors of Precut Techniques Requirement During ERCP CannulationEndoscopy 2021; 53(S 01): C5DOI: 10.1055/s-0041-1729517
Recent Advances in Cardiology
Authors: Derek Rowlands, Bernard Clarke
Journal: JAMA (1949)

From a careful study of many monographs and magazine articles of the last two decades, the authors have produced a book that is far superior to the ordinary compilation. The thoroughness with which the literature has been reviewed, the good judgment shown in rejecting the insignificant and the repetitious, together with the fairness and wisdom of the editorial comment, make the book a valuable and reliable epitome of recent cardiology. One occasionally wonders why certain facts that might be assumed as known and that really are not recent are taken up. But this is evidently done so as to increase the usefulness of the volume to the student or practitioner whose knowledge of these topics may be a bit hazy or whose memory is a little unretentive. Naturally, some subjects appear to be handled in a more satisfactory way than are others. Rheumatic carditis, for example, seems to be more
Cardiac arrhythmias after chronic embolization of the sinus node artery: alterations in parasympathetic pacemaker control.
Authors: J MLoeb, D EEuler, W CRandall, J FMoran, GBrynjolfsson
Journal: Circulation (1980)

Embolization of the sinus node artery was accomplished in dogs by injecting rapidly hardening vinyl latex into the sinus node artery. Embolization immediately shifted the pacemaker to a junctional focus; however, with time postoperatively, the pacemaker shifted to an atrial site. Variable episodes of pacemaker failure, sinoatrial block, junctional rhythm, wandering atrial pacemaker and idioventricular escape rhythms were commonly observed on Holter monitor in isolation but only rarely when the dog was in the laboratory. Severe bradycardia (38.9 +/- 3.7 beats/min) was the predominant rhythm by 3-6 months postoperatively. In addition, these same dogs had a greater overall increase in heart rate after atropine than normal dogs (17.5 +/- 13.5 vs 116.6 +/- 15.9 beats/min above control; p less than 0.02). Responses to vagal stimulation in this group were abnormal, as long periods of asystole and bradycardia were observed after stimulation was terminated. These data suggest an alteration in parasympathetic pacem...
Electrocardiographic body surface mapping in patients with ventricular tachycardia. Assessment of utility in the identification of effective pharmacological therapy.
Authors: L BMitchell, C LHubley-Kozey, E RSmith, D GWyse, H JDuff, A MGillis, B MHoracek
Journal: Circulation (1992)

BACKGROUNDBody surface maps of net QRST deflection areas (isointegrals) reflect regional ventricular repolarization properties. Vulnerability to ventricular tachyarrhythmias is associated with maps that feature multiple islands (extrema) of positive and negative values; such maps reflect regional disparity of ventricular recovery properties. The value of body surface mapping in prediction of the efficacy of antiarrhythmic therapy for ventricular tachyarrhythmias has not been determined.METHODS AND RESULTSIsointegral ECG body surface mapping was performed in 51 patients with inducible ventricular tachycardia having programmed stimulation studies at baseline and after oral quinidine therapy. The degree of nondipolarity of QRST isointegral distribution was expressed by the number of extrema and by the percentage contribution of nondipolar eigenvectors after Karhunen-Loeve transformation. QRST isointegral nondipolarity was greater in ventricular tachycardia patients than in 51 age- and sex-matched normal subj...
Fluoride in Drinking Water, Diet, and Urine in Relation to Bone Mineral Density and Fracture Incidence in Postmenopausal Women
Authors: Emilie Helte, Carolina Donat Vargas, Maria Kippler, Alicja Wolk, Karl Michaëlsson, Agneta Åkesson
Journal: Environmental Health Perspectives (2021)

BACKGROUND: Although randomized controlled trials (RCTs) have demonstrated that high fluoride increases bone mineral density (BMD) and skeletal fragility, observational studies of low-dose chronic exposure through drinking water (<1:5 mg=L, the maximum recommended by the World Health Organization) have been inconclusive.OBJECTIVE: We assessed associations of fluoride in urine, and intake via diet and drinking water, with BMD and fracture incidence in postmenopausal women exposed to drinking water fluoride ≤1 mg=L.METHODS: Data were from participants in the Swedish Mammography Cohort-Clinical, a population-based prospective cohort study.At baseline (2004)(2005)(2006)(2007)(2008)(2009), fluoride exposure was assessed based on urine concentrations (n = 4,306) and estimated dietary intake (including drinking water) (n = 4,072), and BMD was measured using dual energy X-ray absorptiometry.Incident fractures were ascertained via register-linkage through 2017.Residential history was collected to identify women with long-term consistent drinking water exposures prior to baseline.RESULTS: At baseline, mean urine fluoride was 1:2 mg=g creatinine ( ± 1:9) and mean dietary intake was 2:2 mg=d ( ± 0:9), respectively.During followup, 850, 529, and 187 cases of any fractures, osteoporotic fractures, and hip fractures, respectively, were ascertained.Baseline BMD was slightly higher among women in the highest vs. lowest tertiles of exposure.Fluoride exposures were positively associated with incident hip fractures, with multivariableadjusted hazard ratios of 1.50 (95% CI: 1.04, 2.17) and 1.59 (95% CI: 1.10, 2.30), for the highest vs. lowest tertiles of urine fluoride and dietary fluoride, respectively.Associations with other fractures were less pronounced for urine fluoride, and null for dietary fluoride.Restricting the analyses to women with consistent long-term drinking water exposures prior to baseline strengthened associations between fractures and urinary fluoride.DISCUSSION: In this cohort of postmenopausal women, the risk of fractures was increased in association with two separate indicators of fluoride exposure.Our findings are consistent with RCTs and suggest that high consumption of drinking water with a fluoride concentration of ∼ 1 mg=L may increase both BMD and skeletal fragility in older women.
Omega-3 Fatty Acids Effect on Major Cardiovascular Events in Patients at High Cardiovascular Risk
Authors: Yutang Wang
Journal: JAMA (2021)

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
Kinetic properties of 99mTc-Q12 in canine myocardium.
Authors: M CGerson, R WMillard, N JRoszell, A JMcGoron, MGabel, L CWashburn, DBiniakiewicz, DBlankenship, W HMallin, R CElder
Journal: Circulation (1994)

BACKGROUND99mTc-Q12 is a new Tc(III) perfusion imaging agent that permits prompt myocardial visualization in humans. We postulated that 99mTc-Q12 myocardial activity is related to actual myocardial blood flow during conditions of myocardial ischemia and pharmacological coronary artery vasodilation and that 99mTc-Q12 shows little or no myocardial redistribution as long as 4 hours after intravenous injection.METHODS AND RESULTSIn seven anesthetized, open chest dogs, the left circumflex coronary artery was occluded, and dipyridamole (0.32 or 0.56 mg/kg) was infused into the right atrium, followed by 10 mCi of 99mTc-Q12. Myocardial blood flow was measured by radiolabeled microspheres. The animals were euthanized, and a total of 315 myocardial samples were assayed in a well counter for 99mTc activity. One week later, radiolabeled microsphere activity was determined, and myocardial blood flow was calculated. 99mTc activity (y) was related to myocardial blood flow (x) from 0 to 2 mL.g-1 x min-1 by the relation y...
Reply to D. Crivellari et al
Authors: Sileny N. Han, Sibylle Loibl, Ben Van Calster, Patrick Neven, Valentina Nekljudova, Frédéric Amant
Journal: Journal of Clinical Oncology (2013)

ClinicalOncology, Amant et al 1 reported the results from an international collaborative study on prognosis of women with primary breast cancer diagnosed during pregnancy.Their results contrast with those of a recent report 2 on a meta-analysis of 30 studies derived from the literature and that showed a significantly higher risk of death for patients diagnosed during pregnancy or 1 year afterward, with a particular risk for those diagnosed postpartum; this group of patients was not included in the Amant study.In addition, there was no statistically significant difference in disease-free and overall survival at a median follow-up of 61 months in the overall group of 311 evaluable patients.The majority of these patients had triple-negative or human epidermal growth factor receptor 2-positive disease (118 and 145 patients respectively, whereas there were 145 endocrine-responsive patients overall).For these patients at higher risk, no or little effect of hormonal milieu may be anticipated, and activity of targeted agents may have contributed to improve prognosis.On the other hand, in the luminal B cohort a hazard ratio (HR) of 1.73 in overall survival with an extremely large 95% CI (0.63 to 4.75) was reported in the 109 pregnant patients.In their discussion, the authors did not mention this fact.They simply concluded that they found similar survival for patients with pri-mary breast cancer diagnosed during pregnancy when compared with nonpregnant patients after adjusting for known prognostic factors.To better understand differences in the biology of breast cancer this may be at least in part true for triple-negative disease (HR, 1.04; 95% CI, 0.51 to 2.09) or human epidermal growth factor receptor 2-positive disease (HR, 1.34; 95% CI, 0.51 to 3.54) but may be not the case for endocrine-responsive breast cancer, given that only 46 patients were considered with luminal A and 99 patients with luminal B breast cancer (HR, 0.60; 95% CI, 0.08 to 4.68).Therefore, according to our opinion, the conclusions of the authors should be taken with caution particularly for endocrineresponsive patients.As we have no data from evidence-based studies, the issue of the recommendation to proceed with a pregnancy in young hormoneresponsive patients remains an open question.
The Johns Hopkins Hospital 1997 Guide to Medical Care of Patients with HIV Infection
Authors: John A. Robinson
Journal: Annals of Internal Medicine (1998)

Medical Writings1 July 1998The Johns Hopkins Hospital 1997 Guide to Medical Care of Patients with HIV InfectionJohn A. Robinson, MDJohn A. Robinson, MDLoyola University Stritch School of Medicine, Maywood, Illinois.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-129-1-199807010-00031 SectionsAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail The Johns Hopkins Hospital 1997 Guide to Medical Care of Patients with HIV Infection; 7th ed. Bartlett JG. 190 pages. Baltimore: Williams & Wilkins; 1997. $12.00. ISBN 0683303562. Order phone 800-638-0672.Field of medicine: Infectious diseases.Format: Softcover book.Audience: Medical students, residents, infectious disease fellows, general internists, subspecialists, and neurologists.Purpose: To provide guidelines for the care of patients with HIV infection.Content: This guide presents, in a logical sequence, everything the clinician needs to know about caring for patients with HIV infection and AIDS. The final chapter contains a series of helpful algorithms on the care of patients ... Author, Article, and Disclosure InformationAffiliations: Loyola University Stritch School of Medicine, Maywood, Illinois. PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetails Metrics 1 July 1998Volume 129, Issue 1Page: 79-80KeywordsAIDSFever of unknown originGastrointestinal infectionsHIVHIV infectionsInfectious diseasesOutpatient clinicsPatientsPulmonary diseasesSub-specialty care ePublished: 15 August 2000 Issue Published: 1 July 1998 Copyright & PermissionsCopyright © 1998 by American College of Physicians. All Rights Reserved.PDF downloadLoading ...
Differential effects of heptanol, potassium, and tetrodotoxin on reentrant ventricular tachycardia around a fixed obstacle in anisotropic myocardium.
Authors: JBrugada, LMont, LBoersma, CKirchhof, M AAllessie
Journal: Circulation (1991)

BACKGROUNDThe aim of this study was to test the hypothesis that electrical uncoupling and depression of the fast sodium channels have differential effects on propagation of the electrical impulse relative to the fiber orientation.METHODS AND RESULTSIn a model of reentrant ventricular tachycardia (VT) (mean cycle length, 144 +/- 13 msec) around a ring of anisotropic myocardium in 10 Langendorff-perfused rabbit hearts, the effects of extracellular K+ concentration [( K+]o) and heptanol were studied. [K+]o and heptanol each had a dose-dependent effect on VT cycle length. However, high [K+]o slowed the VT mainly by depressing longitudinal conduction, whereas heptanol preferentially depressed transverse conduction. The ratio between longitudinal and transverse conduction velocities progressively decreased with high [K+]o and progressively increased with heptanol. Heptanol terminated VT at a mean concentration of 3.5 +/- 0.5 mM. The cycle length before termination was 446 +/- 120 msec (p less than 0.001). In ei...
From the authors
Authors: G.N. Willson, A.J. Piper, R.R. Grunstein
Journal: European Respiratory Journal (2004)

two types of mask ventilation.Although the questions of this study are relevant, I believe that the design of the study was not adequate to answer these questions.First, all patients were on NM for w3 months and one patient even for 70 months, whereas they trained only for 1 day on FFM.In our centre (Dept of Pulmonary Diseases/ Home mechanical ventilation, University Hospital Groningen, Groningen, The Netherlands), patients routinely need more time (y7 days) to adjust to their specific mask.As a result of this short time of training on FFM compared with a long-term adjustment on NM, it is not surprising that total sleep time and sleep efficiency were worse in the FFM group compared with the NM group.As a consequence of their longer experience with the NM mask, the patients also rated less leak and more comfort in the NM night compared with the FFM night.Secondly, no differences were found between pressure settings if NM was compared with FFM.However, this study will not detect any differences if pressure settings, optimalised during their review night, remained unchanged during the subsequent mask trials.Due to the previously mentioned issues, I believe that the study by WILLSON et al. [1], with its present design, makes it difficult to draw strong conclusions.It would have been preferable to compare both mask ventilations in a parallel study of naı ¨ve patients in whom noninvasive ventilation was started.In this way, it would have been possible to compare the time it takes to adjust to either nasal mask or full face mask.If the patients were adjusted to the mask, it would be possible to determine differences in terms of sleep quality, tolerability and pressure needed to maintain an effective noninvasive ventilation.
Determinants of ventricular defibrillation in adults.
Authors: J AGascho, R SCrampton, M LCherwek, J NSipes, F PHunter, W MO'Brien
Journal: Circulation (1979)

Conventional defibrillators which stored no more than 400 J and used damped sine wave pulses defibrillated 240 of 253 (95%) episodes of ventricular fibrillation (VF) in 94 prospectively assessed resuscitations in 88 adults. Shocks of 80--240 J (under 3 J/kg) delivered to the chest wall defibrillated more often than higher energy levels. Defibrillation rate did not correlate with weight. Defibrillation was determined by the diagnosis and setting in which VF occurred. Patients with acute myocardial infarction (AMI) and primary VF or with coronary disease and no AMI defibrillated more easily than patients with AMI and secondary VF or with no coronary disease. VF in a terminal patient (agonal VF) defibrillated less often than VF in other clinical situations. Age, weight, delivered energy, duration of pulse wave, and duration of VF had little, if any, influence on rate of defibrillation. These data fail to support the use of more expensive, high-output defibrillators sold by 11 or 14 American manufactures.
A cellular mechanism for impaired posthypoxic relaxation in isolated cardiac myocytes. Altered myofilament relaxation kinetics at reoxygenation.
Authors: H SSilverman, MNinomiya, P SBlank, OHano, HMiyata, H ASpurgeon, E GLakatta, M DStern
Journal: Circulation Research (1991)

Single, isolated rat ventricular myocytes were made hypoxic for 10 minutes and then reoxygenated. During hypoxia, there was a marked abbreviation of the mechanical twitch, without a decrease in its amplitude. Immediately after reoxygenation, both the time to peak shortening and the duration of relaxation were markedly prolonged, and they remained prolonged for 10-50 minutes. The alterations in contraction and relaxation were not associated with any change in the time course of either the transmembrane action potential or the cytosolic calcium transient, as recorded with the fluorescent probe indo 1. Intracellular pH, measured with a fluorescent probe (carboxyseminaphthorhodofluor), showed an acid shift during hypoxia and an alkaline rebound immediately after reoxygenation. The time courses of intracellular pH and contraction duration were not parallel during hypoxia or reoxygenation, and simulation of the alkaline pH shift by lowering PCO2 or superfusing NH4Cl (in the absence of exposure to hypoxia) did n...
Hormonal control of plasma renin substrate; (angiotensinogen).
Authors: L RKrakoff, A JEisenfeld
Journal: Circulation Research (1977)

The effect of ethinyl estradiol (EE2) and dexamethasone (Dex) upon plasma renin substrate (PRS) was studied in rats in relation to sexual maturation and pituitary function. Normal adult rats had large increases in PRS when given either EE2 or Dex. Prepubescent (25-day-old) rats also had a substantial increase in PRS following Dex, but no increase in PRS after EE2. In adult rats, hypophysectomy prevented the rise in PRS due to EE2 but did not prevent the increase in PRS due to Dex. Hepatic estrogen and glucocorticoid receptors were measured in immature and adult rats. Immature rats had markedly reduced concentration of hepatic estrogen receptors (16%), compared with adults. In contrast, glucocorticoid receptor concentration was not significantly different between immature and adult rats. The results indicate that the effect of estrogens and glucocorticoids upon PRS are mediated by pathways that are separable at the hormone receptor level.
Smooth and skeletal muscle actin are mechanically indistinguishable in the in vitro motility assay.
Authors: D EHarris, D MWarshaw
Journal: Circulation Research (1993)

Smooth muscle produces as much stress as skeletal muscle with less myosin. To determine if the actin isoforms specific to smooth muscle contribute to the enhanced force generation, the motility of actin filaments from smooth and skeletal muscle were compared in an in vitro assay in which single fluorescently labeled actin filaments slide over a myosin-coated coverslip. No difference was observed between the velocity of smooth versus skeletal muscle actin filaments over either smooth or skeletal muscle myosin over a large range of assay conditions (changes in pH, ionic strength, and [ATP]). Similarly, no difference was observed between the two actins when the filaments moved under load over mixtures of phosphorylated smooth and skeletal muscle myosin. Thus, it appears that the actin isoforms of smooth and skeletal muscle are mechanically indistinguishable in the motility assay and that smooth muscle's enhanced force generation may originate within the myosin molecule specific to smooth muscle.