tbuckley/cabot-search huggingface dataset:
Regulation of myosin heavy chain expression in the hearts of hypertensive rats by testosterone.
Authors: IMorano, JGerstner, J CRüegg, UGanten, DGanten, H PVosberg
Journal: Circulation Research (1990)

Stroke-prone spontaneously hypertensive rats were used for our investigation of the influence of prepubertal gonadectomy and testosterone substitution on blood pressure, cardiac hypertrophy, and the expression of ventricular myosin heavy chain (MHC) isoenzymes at different developmental stages. Blood pressure and the degree of cardiac hypertrophy were decreased by castration and increased by testosterone substitution. We found the same relative distributions of MHC isoforms on the protein level (investigated by pyrophosphate electrophoresis) and on the messenger RNA level (investigated by the polymerase chain reaction). Castration favored the expression of the beta-MHC form, and testosterone substitution enhanced the expression of the alpha-MHC form. These effects were more pronounced in 8-week-old than in 14-16-week-old animals. We conclude that testosterone regulates cardiac MHC expression on a pretranslational level. This regulation is independent of hemodynamic load or cardiac hypertrophy.
Relationship between central hemodynamics and regional blood flow in normal subjects and in patients with congestive heart failure.
Authors: M ELeithe, R DMargorien, J BHermiller, D VUnverferth, C VLeier
Journal: Circulation (1984)

Central and regional (hepatic, renal, and limb) hemodynamic data are presented for a normal population (n = 16) and for a group of patients with congestive heart failure (n = 64). The patient population represented a wide spectrum of severity of congestive heart failure. Various relationships between central and regional hemodynamics were analyzed. The results indicate that in congestive heart failure blood flow to hepatic, renal, and limb regions is significantly decreased, and that this decrease is proportional and linearly related to the reduction in cardiac output. The vascular resistances of these regions correlated directly with systemic vascular resistance. Changes in renal vascular resistance and renal blood flow became attenuated as the severity of the heart failure advanced from moderate to severe and at higher levels of systemic vascular resistance. There was little to no correlation between systemic blood pressure and liver, kidney, and limb blood flow for the range of systemic pressures studied.
Effects of beta-adrenergic stimulation with dobutamine on isovolumic relaxation in the normal and failing human left ventricle.
Authors: J DParker, J SLandzberg, J ABittl, IMirsky, W SColucci
Journal: Circulation (1991)

BACKGROUNDWe tested the hypothesis that beta-adrenergic receptor-stimulated acceleration of left ventricular (LV) isovolumic relaxation (i.e., positive lusitropic response) is attenuated in patients with severe congestive heart failure (CHF) compared with patients without LV dysfunction or CHF.METHODS AND RESULTSThe beta-adrenergic agonist dobutamine was infused by the intracoronary route in 14 subjects (normal group, six; CHF patients, eight) and by the intravenous route in a second group of 14 subjects (normal group, four; CHF patients, 10). The positive inotropic response to intracoronary or intravenous dobutamine was substantially and significantly reduced in the patients with CHF. LV isovolumic relaxation rate was determined by the methods of Weiss (TL), Mirsky (T1/2), and by a nonlinear regression technique (TNL). LV isovolumic relaxation assessed by all three methods was significantly prolonged in CHF patients compared with normal subjects. Intracoronary and intravenous infusions of dobutamine caus...
Effects of endothelin on the coronary vascular bed in open-chest dogs.
Authors: J PClozel, MClozel
Journal: Circulation Research (1989)

The goal of the present study was to evaluate the effects of endothelin, a newly discovered very potent vasoconstrictor secreted by endothelial cells, on the coronary vascular bed. For this purpose, the effects of endothelin injected intracoronarily were tested in open-chest anesthetized dogs with the circumflex coronary artery cannulated and perfused at a constant pressure of 100 mm Hg. Circumflex blood flow, transmural distribution of coronary blood flow (radioactive microspheres), circumflex coronary artery diameter (piezoelectric crystals), and circumflex luminal surface area were measured. Endothelin decreased coronary blood flow by 30% and 61% with doses of 1 and 3 micrograms, respectively. A dose of 10 micrograms was lethal. The decrease of coronary blood flow was larger in the subepicardium than in the subendocardium, which explains that the endocardial-epicardial blood flow ratio increased from 1.27 +/- 0.05 to 1.98 +/- 0.23 (p less than 0.001) with a dose of 3 micrograms endothelin. Circumflex s...
Pressure gradient related to energy conversion in the aorta.
Authors: JMelbin, ANoordergraaf
Journal: Circulation Research (1983)

In this study, we analyzed a common form of experimental investigation of blood vessels, in which measurements are obtained with branches ligated. Utilizing representative pressure and flow pulses and the full expression for the equation of motion, we calculated the axial pressure gradient, in the time domain at a plane in the descending aorta. The time function representing the ratio between axial pressure gradient and axial flow for the resulting tapering geometry was subjected to Fourier analysis. The harmonics were utilized to obtain the real and imaginary components of the longitudinal impedance as if it were a linear system. In a linear system, the real and imaginary components represent the viscous and inertial properties of the fluid, respectively. For the system studied, however, the real part contained both viscous and substantial in-phase components arising from the inertial terms of the equation of motion. The real part, therefore, cannot be interpreted as indicative solely of dissipated energ...
Sexual Desire and Arousal Disorders in Women
Authors: Rosemary Basson
Journal: New England Journal of Medicine (2006)

A 46-year-old woman, married for 16 years, reports having had a low level of sexual desire and minimal sexual arousal during sexual activity for the past 10 years. Sexual thoughts, fantasies, and orgasms are all extremely rare. Lubrication is sufficient to allow painless intercourse. She and her husband have an eight-year-old son who was born after in vitro fertilization for unexplained infertility. How should this patient be assessed and treated?
Effect of ventilation on resuscitation in an animal model of cardiac arrest.
Authors: A HIdris, L BBecker, R SFuerst, VWenzel, W JRush, R JMelker, D JOrban
Journal: Circulation (1994)

BACKGROUNDThe need for ventilation during the initial management of cardiac arrest is an important public health problem that is being debated. The present study was designed to determine whether ventilation affects return of spontaneous circulation from cardiac arrest in a swine model with an interval of untreated ventricular fibrillation of 6 minutes, as reported in witnessed out-of-hospital human cardiac arrest.METHODS AND RESULTSTwenty-four animals were randomly assigned to two groups: one that received ventilation during the first 10 minutes of chest compression and one that did not. Coronary perfusion pressure and minute ventilation were continuously recorded. Arterial and mixed venous blood gases were measured at intervals. Return of spontaneous circulation was defined prospectively as an aortic systolic blood pressure of > 80 mm Hg for > 5 minutes and was the primary outcome variable. All animals were anesthetized, paralyzed, and intubated. Ventricular fibrillation was induced and persisted for 6 ...
E-type prostaglandins: a new emergency therapy for certain cyanotic congenital heart malformations.
Authors: P MOlley, FCoceani, EBodach
Journal: Circulation (1976)

Prostaglandin E2 (PGE2) has been used to maintain patency of the ductus arteriosus in four neonates with cyanotic congenital heart disease due to obstructive right heart malformations. PGE2 was infused prior to surgery, and in three patients, during surgery until a satisfactory aorto-pulmonary shunt was established. PGE2 produced consistently an immediate and persistent rise in arterial oxygen saturation, which could be ascribed to dilation of the ductus arteriosus. No major side effects occurred, except for pyrexia in two infants. All patients recovered well from surgery. We propose this treatment as preparation for surgery in any infant with congenital heart defects and ductus-dependent pulmonary blood flow. The same treatment may be useful preoperatively in patients with aortic interruption who also depend on continued patency of the ductus for blood supply to the lower half of the body.
Accuracy of Endoscopic Ultrasound (EUS)-Elastography in the Diagnosis of Patients With Early Changes of Chronic Pancreatitis
Authors: J Iglesias-Garcia, J Lariño-Noia, D De la Iglesia-Garcia, L Nieto, S Leal-Lopez, S Lojo, JE Dominguez-Muñoz
Journal: Endoscopy (2021)

Aims Evaluate the accuracy of EUS-elastography for the diagnosis of early CP using the ePFT as reference in patients with suspected early CP. Correlation between the degree of pancreatic fibrosis and pancreatic secretion of bicarbonate was also evaluated.
In Search of the Best Way to Identify Those Who Would Benefit Most From COVID-19 Vaccination—Who Goes First?
Authors: Carlos del Rio, Saad Omer
Journal: JAMA Network Open (2021)

George N. Ioannou, BMBCh, MS; Pamela Green, PhD; Vincent S. Fan, MD, MS; Jason A. Dominitz, MD, MHS; Ann M. O'Hare, MD; Lisa I. Backus, MD, PhD; Emily Locke, MPH; McKenna C. Eastment, MD; Thomas F. Osborne, MD; Nikolas G. Ioannou; Kristin Berry, PhD
Low Impact of Genetic Modifiers on the Phenotype of Homozygous Beta Thalassemia in the Last Decennial Cohort of Thalassemia Newborns in Sardinia
Authors: Paolo Moi, Matteo Marcello, Stefania Satta, Laura Manunza, Franca Rosa De Martis, Raffaella Origa, Giovanni Caocci, Susanna Barella
Journal: Blood (2017)
Effects of the angiotensin converting enzyme inhibitor enalapril on the long-term progression of left ventricular dilatation in patients with asymptomatic systolic dysfunction. SOLVD (Studies of Left Ventricular Dysfunction) Investigators.
Authors: M AKonstam, M WKronenberg, M FRousseau, J EUdelson, JMelin, DStewart, NDolan, T REdens, SAhn, DKinan
Journal: Circulation (1993)

BACKGROUNDPatients with heart failure and reduced left ventricular (LV) ejection fraction (EF) manifest progressive LV dilatation, which is prevented by angiotensin converting enzyme (ACE) inhibitors. In patients with asymptomatic LV systolic dysfunction, in whom there is less activation of the renin-angiotensin system, ventricular remodeling might be less rapid and the benefit of ACE inhibitors less discernible.METHODS AND RESULTSOne hundred eight patients enrolled in the Studies of Left Ventricular Dysfunction (SOLVD) Prevention Trial, with left ventricular ejection fraction < or = 0.35 but without clinical heart failure, underwent radionuclide ventriculograms, and 49 underwent left heart catheterizations. Measurements were made before and after double-blinded randomization to enalapril (2.5 to 20 mg/d) or placebo. Repeated-measures analysis of all time points showed significant differences for change in end-diastolic volume (EDV) between enalapril and placebo groups. Significant difference between the ...
Artificial Intelligence in Hypertension
Authors: Sandosh Padmanabhan, Tran Quoc Bao Tran, Anna F. Dominiczak
Journal: Circulation Research (2021)

Hypertension remains the largest modifiable cause of mortality worldwide despite the availability of effective medications and sustained research efforts over the past 100 years. Hypertension requires transformative solutions that can help reduce the global burden of the disease. Artificial intelligence and machine learning, which have made a substantial impact on our everyday lives over the last decade may be the route to this transformation. However, artificial intelligence in health care is still in its nascent stages and realizing its potential requires numerous challenges to be overcome. In this review, we provide a clinician-centric perspective on artificial intelligence and machine learning as applied to medicine and hypertension. We focus on the main roadblocks impeding implementation of this technology in clinical care and describe efforts driving potential solutions. At the juncture, there is a critical requirement for clinical and scientific expertise to work in tandem with algorithmic innovation followed by rigorous validation and scrutiny to realize the promise of artificial intelligence-enabled health care for hypertension and other chronic diseases.
Flow-mediated dilatation of the basilar artery in vivo.
Authors: KFujii, D DHeistad, F MFaraci
Journal: Circulation Research (1991)

Flow-mediated dilatation has been described mainly in peripheral conduit arteries. The goal of this study was to examine mechanisms and functional implications of flow-mediated dilatation in large cerebral arteries in vivo. Vessel diameter and velocity of blood flow through the basilar artery were measured using a cranial window in 45 anesthetized rats. Mean blood flow velocity through the basilar artery increased by 94 +/- 8% during unilateral common carotid artery occlusion and 203 +/- 13% during bilateral occlusion. Diameter of the basilar artery increased by 10 +/- 1% during unilateral common carotid artery occlusion and 29 +/- 2% during bilateral occlusion from control diameter of 275 +/- 8 microns. Vasodilatation appeared with a delay of 13 +/- 1 seconds after the onset of the increase in flow velocity. With systemic arterial pressure maintained at baseline levels, pressure in the basilar artery (servonull) decreased initially during carotid occlusion, and during dilatation of the basilar artery, pr...
An APP ectodomain mutation outside of the Aβ domain promotes Aβ production in vitro and deposition in vivo
Authors: Xulun Zhang, Can Martin Zhang, Dmitry Prokopenko, Yingxia Liang, Sherri Y. Zhen, Ian Q. Weigle, Weinong Han, Manish Aryal, Rudolph E. Tanzi, Sangram S. Sisodia
Journal: The Journal of Experimental Medicine (2021)

Familial Alzheimer's disease (FAD)-linked mutations in the APP gene occur either within the Aβ-coding region or immediately proximal and are located in exons 16 and 17, which encode Aβ peptides. We have identified an extremely rare, partially penetrant, single nucleotide variant (SNV), rs145081708, in APP that corresponds to a Ser198Pro substitution in exon 5. We now report that in stably transfected cells, expression of APP harboring the S198P mutation (APPS198P) leads to elevated production of Aβ peptides by an unconventional mechanism in which the folding and exit of APPS198P from the endoplasmic reticulum is accelerated. More importantly, coexpression of APP S198P and the FAD-linked PS1ΔE9 variant in the brains of male and female transgenic mice leads to elevated steady-state Aβ peptide levels and acceleration of Aβ deposition compared with age- and gender-matched mice expressing APP and PS1ΔE9. This is the first AD-linked mutation in APP present outside of exons 16 and 17 that enhances Aβ production and deposition.
Fatty acid metabolism and contractile function in the reperfused myocardium. Multinuclear NMR studies of isolated rabbit hearts.
Authors: D LJohnston, E DLewandowski
Journal: Circulation Research (1991)

The hypothesis that substrate availability can alter contractile function in reperfused myocardium after global ischemia was investigated in this study. Isolated rabbit hearts were placed in a dual tuned (31P/13C) NMR probe with a 9.4-T magnet and perfused with the following substrates given individually or in combination: 10 mM glucose, 2 mM palmitate, and 2.5 mM [3-13C]pyruvate. Glucose was the sole substrate present for all groups of hearts before the onset of 10 or 20 minutes of zero-flow ischemia. Contractility (dP/dt) was significantly higher in hearts reperfused with glucose compared with hearts reperfused with palmitate or the combination. In addition, myocardial oxygen consumption/unit of work at reperfusion was more efficient with glucose than with palmitate. ATP content during reperfusion was similar with glucose and palmitate and did not account for improved function with glucose. To determine if inhibition of pyruvate metabolism by palmitate might result in altered postischemic function, addi...
Long-term results of catheter ablation of idiopathic right ventricular tachycardia.
Authors: FMorady, A HKadish, LDiCarlo, W HKou, SWinston, MdeBuitlier, HCalkins, SRosenheck, JSousa
Journal: Circulation (1990)

Ten consecutive patients with recurrent episodes of symptomatic, idiopathic, sustained monomorphic ventricular tachycardia (VT) originating in the right ventricle underwent an attempt at catheter ablation of the ventricular tachycardia. There were seven women and three men, with a mean age of 39 +/- 14 years (+/- SD). None of the patients had any evidence of structural heart disease. The VT had a left bundle branch block configuration and an inferior axis in each patient, and the mean cycle length was 313 +/- 75 msec. Based on the methods of induction of the VT and the response of the VT to verapamil, the VT mechanism was presumed to be reentry in six patients, triggered activity in three patients, and catecholamine-sensitive automaticity in one patient. Sites for ablation were guided by pace mapping, and an appropriate target site was identified in the right ventricular outflow tract in each patient. From one to three shocks of 100-360 J (mean total, 336 +/- 195 J) were delivered from a defibrillator bet...
The renin-angiotensin system and volume overload-induced changes in cardiac collagen and elastin.
Authors: MRuzicka, F WKeeley, F HLeenen
Journal: Circulation (1994)

BACKGROUNDBesides cardiac load, the renin-angiotensin system (RAS) and aldosterone may regulate collagen accumulation during maturation or hypertrophic growth. The effect of cardiac volume overload on both left ventricular (LV) and right ventricular (RV) collagen and elastin and the possible role of the RAS in such changes have not yet been assessed.METHODS AND RESULTSIn the present study we assessed (1) the effects of 4 to 10 weeks of volume overload by an aortocaval shunt or minoxidil on LV and RV collagen and elastin and (2) the potential of the angiotensin-converting enzyme inhibitor enalapril and the angiotensin II receptor blocker losartan to prevent and regress volume overload-induced changes in cardiac collagen and elastin. Cardiac volume overload by aortocaval shunt or minoxidil treatment decreased LV collagen accumulation as compared with control rats. In contrast, RV collagen accumulation was potentiated during the initial weeks but not during chronic aortocaval shunt. Enalapril and losartan pr...
Alpha-adrenergic receptors in rat myocardium. Identification by binding of [3H]dihydroergocryptine.
Authors: R SWilliams, R JLefkowitz
Journal: Circulation Research (1978)

[3H]Dihydroergocryptine ([3H]DHE) binds to sites in membranes derived from rat myocardium that have the characteristics expected of alpha-adrenergic receptors. The binding is saturable with 41 fmol [3H]DHE bound per mg of protein and of high affinity with KD = 2.9 nM. The binding is rapid and readily reversible. Adrenergic agonists compete with [3H]DHE for binding in the order: epinephrine greater than norepinephrine greater than isoproterenol; and adrenergic antagonists compete for binding in the order: phentolamine greater than propranolol. For comparison, (-)[3H]dihydroalprenolol [(-)[3h]dha] was used to bind to sites in the same membrane preparations having characteristics of beta-receptors. The number and affinity of beta-receptors were quite similar to those of the alpha-receptors with 46 fmol (-)[EH]DHA per mg protein bound at saturation and KD = 2.5 nM. These techniques allowed identification of both beta- and alpha-adrenergic receptors in membranes derived from isolated atria, right ventricular f...
Blunted nocturnal fall in blood pressure in hypertensive women with future cardiovascular morbid events.
Authors: PVerdecchia, GSchillaci, CGatteschi, IZampi, MBattistelli, CBartoccini, CPorcellati
Journal: Circulation (1993)

BACKGROUNDIn essential hypertension, a blunted or absent nocturnal fall in blood pressure (BP) may be associated with increased target organ damage. In this case-control study, we tested the hypothesis that an association exists between a blunted or absent nocturnal fall in BP and future cardiovascular morbid events in patients with essential hypertension.METHODS AND RESULTSCase subjects were 32 hypertensive patients with a first fatal or nonfatal major cardiovascular event who had off-therapy ambulatory BP monitoring 1 to 5 years earlier in the context of a registry of morbidity and mortality in hypertensive patients. Control subjects were 49 hypertensive patients free from cardiovascular events. The groups were matched with regard to date of baseline ambulatory BP monitoring, age, sex, clinic systolic and diastolic BP, and daytime ambulatory systolic and diastolic BP. At their baseline evaluation, cases and controls did not differ, in either sex, with respect to clinic BP (men, 164/100 vs 162/99 mmHg; w...
Sequence of events in angina at rest: primary reduction in coronary flow.
Authors: SChierchia, CBrunelli, ISimonetti, MLazzari, AMaseri
Journal: Circulation (1980)

To investigate the events that lead to acute myocardial ischemia we monitored continuously the ECG, the left ventricular (four patients) or aortic (two patients) pressure and the great cardiac vein oxygen saturation (CSO2S) by a fiberoptic catheter in six patients with frequent anginal attacks at rest. We recorded 137 transient ischemic episodes (10 with chest pain) characterized by ST-segment elevation in 28 episodes, depression in three episodes and by pseudonormalization of previously inverted or flat T waves in 106 episodes. The onset of electrocardiographic and hemodynamic changes was preceded by a large drop in CSO2S in all 135 episodes with ST-T changes in the anterior leads but not in two episodes with ST elevation on inferior leads. The fall in CSO2S, consistently followed by signs of left ventricular function impairment and never preceded by any detectable increase in the hemodynamic determinants of myocardial oxygen consumption, probably reflects a reduction in regional perfusion. Thus, a reduc...
Effects of atropine on diastolic time.
Authors: K AConrad
Journal: Circulation (1981)

Atropine was given intravenously to 10 normal volunteers in increments of 0.01 mg/kg to a total dose of 0.04 mg/kg. This produced an increase in heart rate from 65 +/- 11 to 112 +/- 14 beats/min, a decrease in diastolic time from 534 +/- 131 to 180 +/- 65 msec, and a decrease in percent diastole from 55.6 +/- 5.3% to 32.4 +/- 7.2% (p < 0.001). Administration of isoproterenol in doses that increased heart rate from 69 +/- 9 to 99 +/- 12 beats/min produced a decrease in diastolic time from 485 +/- 98 to 312 +/- 47 msec and only a slight decrease in percent diastole, from 54.2 +/- 4.3% to 50.6 +/- 3.9%. Atropine, in doses commonly used clinically, may significantly reduce diastolic time and the percent diastole. Because diastolic time is an important determinant of coronary perfusion, administration of atropine to patients with coronary artery disease may increase myocardial ischemia.