tbuckley/cabot-search huggingface dataset:
Capillary perfusion of the rat brain cortex. An in vivo confocal microscopy study.
Authors: AVillringer, AThem, ULindauer, KEinhäupl, UDirnagl
Journal: Circulation Research (1994)

Confocal laser-scanning microscopy was used to visualize subsurface cerebral microvessels labeled with intravascular fluorescein in a closed cranial window model of the anesthetized rat. In noninvasive optical sections up to 250 microns beneath the brain surface, plasma perfusion and blood cell perfusion of individual capillaries were studied. Under resting conditions, in all cerebral capillaries the presence of plasma flow as demonstrated by the appearance of an intravenously injected fluorescent tracer within 20 seconds after injection. Plasma flow was verified even in capillaries that contained stationary erythrocytes or leukocytes; 91.1% of the capillaries contained flowing blood cells, 5.2% contained stationary blood cells, and no blood cells were seen in 3.6%. Mean blood cell velocity was 498.3 +/- 443.9 microns/s, and the mean blood cell supply rate was 35.75 +/- 28.01 cells per second. When capillaries were continuously observed for 1 minute, on and off periods of blood cell flow were noted. D...
Low Grade Neoplasia And Colorectal (CR) Endoscopic Submucosal Dissection (ESD): Are The Adverse Events Acceptable? Results Of A Prospective Multicentre Registry
Authors: JC Marín-Gabriel, A Herreros-de-Tejada, F Ramos-Zabala, PJ Rosón-Rodríguez, Á Terán-Lantarón, E Albéniz-Arbizu, J Santiago-García, H Uchima-Koecklin, J Rodríguez-Sánchez, U Goikoetxea-Rodero, A Sánchez-Yagüe, A Amorós-Tenorio, D García-Romero, Ó Nogales-Rincón, G Fernández-Esparrach, E Rodríguez-de-Santiago, S Parejo-Carbonell, B Peñas-García, P De-María-Pallarés, A del-Pozo-García, J Gordillo-Ábalos, D Pérez, C Dolz-Abadía, P Miranda-García, H Cortés-Pérez, A Álvarez-Delgado, R Durán-Bermejo, O Díaz-Canel, D Busquets, M Bustamante-Balen, L Rivero-Sánchez, A Burgos-García, P Gonçalves-da-Cunha, C Guarner-Argente, J Díaz-Tasende
Journal: Endoscopy (2021)

Aims The European Society of Gastrointestinal Endoscopy (ESGE) has recently published a position statement for optical diagnosis suggesting that, for Vienna category (VC)≤ 3 colorectal lesions (CRL), performing EMR would be sufficient therapy. Our aims were: 1.) to assess the ESD complication rates when comparing VC≤ 3 vs. VC≥ 4 CRL and 2.) to compare the overall ESD risk of complications with a previously published Spanish EMR series.
Relation between right ventricular mass and cavity size: an analysis of 1500 human hearts.
Authors: L GHoran, N CFlowers, C JHavelda
Journal: Circulation (1981)

We examined data on the mass, area and myocardial abnormality (scar or infarction) of the right ventricular free wall (RVFW) from 1500 consecutive dissections of hearts that came to autopsy. There were 447 hearts with associated coronary and ischemic heart disease (CAD) and 826 without CAD. RVFW mass was used as an index of hypertrophy (RVH) and RVFW area was used as an index of dilatation (RVD). In both groups of hearts, RVH and RVD were strongly correlated and can be properly referred to as one entity: right ventricular enlargement (RVE). Right ventricular infarction occurred both with and without RVE but rarely without CAD. Right ventricular infarction usually assumed an apical or basal pattern of distribution parallel to that of the adjacent left ventricular lesion.
Quantification of relative coronary arterial stenosis by cinevideodensitometric analysis of coronary arteriograms.
Authors: A BNichols, C FGabrieli, J JFenoglio, P DEsser
Journal: Circulation (1984)

A computerized method for measuring relative coronary arterial stenosis by cinevideodensitometric analysis of 35 mm coronary arteriograms was developed and validated. Video images of projected coronary arteriographic frames were digitized into a 512 X 512 matrix (256 gray levels) by computer analysis that compared integrated contrast density measured over stenotic and normal arterial segments after background subtraction. Pixel density was 70 to 80 pixels/mm2 actual area. In phantom studies performed on plexiglass cylinders, cinevideodensitometric measurements correlated linearly with concentration of contrast medium (r = .99), with cross-sectional areas (r = .99) of contrast-filled cylinders 1 to 4 mm in diameter over a wide range of contrast concentrations (25% to 100%), and with relative stenosis of eccentric lesions in the cylinders (r = .99, SEE = 3.9%). In postmortem studies of patients who died after undergoing coronary arteriography, videodensitometric measurements of relative stenosis correlated ...
Vasa vasorum in atherosclerotic coronary arteries: responses to vasoactive stimuli and regression of atherosclerosis.
Authors: J KWilliams, M LArmstrong, D DHeistad
Journal: Circulation Research (1988)

The goals of this study were to determine whether vasa vasorum in atherosclerotic coronary arteries respond to vasoactive stimuli and to examine effects of regression of atherosclerosis on blood flow through vasa vasorum in coronary arteries. We studied three groups of monkeys: normal, atherosclerotic, and regression. Blood flow to vasa vasorum was measured with microspheres. Blood flow to intima-media (ml/min x 100 g) was 5 +/- 1 (mean +/- SEM) in normal and 47 +/- 7 in atherosclerotic monkeys (p less than 0.05). Infusion of phenylephrine or serotonin did not alter flow through vasa in normal monkeys. In atherosclerotic monkeys, phenylephrine decreased flow through vasa vasorum in intima-media of coronary arteries to 24 +/- 4 (p less than 0.05), and serotonin decreased flow to 27 +/- 5 (p less than 0.05). In regression monkeys, blood flow to intima-media was sixfold less (7 +/- 2 ml/min x 100 g) than in atherosclerotic monkeys (p less than 0.05). During infusion of adenosine, blood flow to vasa was fourf...
Dietary fish oil reduces leukocyte/endothelium interaction following systemic administration of oxidatively modified low density lipoprotein.
Authors: H ALehr, CHübner, BFinckh, DNolte, UBeisiegel, AKohlschütter, KMessmer
Journal: Circulation (1991)

BACKGROUNDIn vitro and in vivo experiments have demonstrated the role of oxidatively modified low density lipoprotein (oxLDL) in eliciting leukocyte/endothelium interaction during early atherogenesis.METHODS AND RESULTSIn the present study we investigated the effect of dietary fish oil on oxLDL-induced leukocyte/endothelium interaction using intravital fluorescence microscopy in the dorsal skinfold chamber model in awake Syrian golden hamsters. Hamsters were fed for 4 weeks prior to the experiments with either standard laboratory chow or a diet supplemented with 5% of a fish oil concentrate (18% eicosapentaenoate, 12% docosahexaenoate). The efficacy of the fish oil diet was demonstrated by the incorporation of fish oil-derived omega-3 fatty acids into plasma, leukocyte, and erythrocyte lipids. In control hamsters (n = 7) and fish oil-fed hamsters (n = 7), leukocyte/endothelium interaction was assessed in the time course after intravenous injection of human LDL (4 mg/kg), oxidized by 7.5 microM Cu2+ (6 hou...
NG-monomethyl L-arginine inhibits endothelium-derived relaxing factor-stimulated cyclic GMP accumulation in cocultures of endothelial and vascular smooth muscle cells by an action specific to the endothelial cell.
Authors: R AJohns, M JPeach, JLinden, ATichotsky
Journal: Circulation Research (1990)

The effect of NG-monomethyl L-arginine (LNMMA), an analogue of L-arginine (a proposed precursor of endothelium-derived relaxing factor [EDRF]), on EDRF release from bovine pulmonary artery endothelial cells was investigated using endothelial cell-vascular smooth muscle cocultures and a superfused column containing endothelial cells grown on microcarrier beads. Cocultures were stimulated with control buffer, ATP, bradykinin, melittin, A23187, or nitroprusside in the presence and absence of varying concentrations of LNMMA (30-300 microM). LNMMA caused significant, concentration-dependent decreases in cyclic GMP accumulation in response to the endothelium-dependent dilators bradykinin, ATP, melittin, and A23187 but had no effect on control or nitroprusside-stimulated cocultures. The inhibitory effect of LNMMA on cyclic GMP accumulation was partially reversed by treatment with L-arginine, but was unaffected by D-arginine. To determine the specific site of action of LNMMA, endothelial cells on microcarrier bea...
The association between blood pressure, age, and dietary sodium and potassium: a population study.
Authors: K TKhaw, EBarrett-Connor
Journal: Circulation (1988)

We examined the relationship between blood pressure and dietary sodium and potassium intake estimated from 24 hr diet recall in a population of 584 men and 718 women 30 to 79 years old in Southern California. In men, but not women, age-adjusted systolic and diastolic blood pressure correlated significantly with dietary sodium intake. In both men and women, age-adjusted diastolic blood pressure significantly inversely correlated with dietary potassium intake. Age-adjusted systolic and diastolic blood pressure correlated significantly with the dietary sodium/potassium ratio in each sex; correlations were better for the ratio than for either sodium or potassium alone. The relationship was apparent over the whole range of blood pressure and dietary intake. A marked age gradient was apparent in men, the regression slope for blood pressure vs sodium/potassium ratio increasing with increasing age, suggesting increasing sensitivity to dietary sodium/potassium ratio with age. Adjusting for intake of other dietary ...
Reversible asynergy. Histopathologic and electrographic correlations in patients with coronary artery disease.
Authors: M MBodenheimer, V SBanka, G AHermann, R GTrout, HPasdar, R HHelfant
Journal: Circulation (1976)

Histopathologic-electrographic studies of ventriculography depicted nitroglycerin responsive and unresponsive asynergic areas were performed in 25 patients. Of 29 areas, 12 improved with nitroglycerin, showing less than 10% muscle loss. Seventeen unimproved zones demonstrated significant fibrosis. Epicardial electrograms showed R waves in eight of nine improved zones. Of 11 unimproved zones, eight had Q waves. Histopathologic-electrographic data from five responders showed less than 10% muscle loss, of whom four had epicardial R waves. Six unresponsive areas had significant fibrosis, with a QS over four. Thus, nitroglycerin responsive asynergic areas are generally comprised of histologically intact myocardium and are associated with epicardial R waves.
Regular physical exercise and low-fat diet. Effects on progression of coronary artery disease.
Authors: GSchuler, RHambrecht, GSchlierf, JNiebauer, KHauer, JNeumann, EHoberg, ADrinkmann, FBacher, MGrunze
Journal: Circulation (1992)

BACKGROUNDSignificant regression of coronary and femoral atherosclerotic lesions has been documented by angiographic studies using aggressive lipid-lowering treatment. This study tested the applicability and effects of intensive physical exercise and low-fat diet on coronary morphology and myocardial perfusion in nonselected patients with stable angina pectoris.METHODS AND RESULTSPatients were recruited after routine coronary angiography for stable angina pectoris; they were randomized to an intervention group (n = 56) and a control group on usual care (n = 57). Treatment comprised intensive physical exercise in group training sessions (minimum, 2 hr/wk), daily home exercise periods (20 min/d), and low-fat, low-cholesterol diet (American Heart Association recommendation, phase 3). No lipid-lowering agents were prescribed. After 12 months of participation, repeat coronary angiography was performed; relative and minimal diameter reductions of coronary lesions were measured by digital image processing. Cha...
Mechanism of altered patterns of left ventricular filling during the development of congestive heart failure.
Authors: MOhno, C PCheng, W CLittle
Journal: Circulation (1994)

BACKGROUNDThe mechanism of the alterations in the pattern of left ventricular (LV) filling during the development of congestive heart failure (CHF) is not fully understood.METHODS AND RESULTSWe studied six conscious dogs instrumented to measure LV and left atrial (LA) pressures and LV volume as CHF was induced by rapid pacing. Diastolic filling dynamics were serially measured over 4 weeks during normal sinus rhythm. Four days after we initiated pacing, the peak early diastolic filing rate decreased from 108 +/- 24 to 88 +/- 27 mL/s (P < .05) as the maximal early diastolic LA-LV pressure gradient decreased associated with a slowing of the rate of LV relaxation. Subsequently, the peak early filling rate progressively increased, returning to control at 1 week, and by the fourth week, it had increased to 168 +/- 39 mL/s (P < .05). These changes in early filling rates occurred as the maximal early diastolic LA-LV pressure gradient increased in association with a progressive increase in LV pressure despite furt...
Repolarization abnormalities in survivors of out-of-hospital ventricular fibrillation.
Authors: R EHaynes, A PHallstrom, L ACobb
Journal: Circulation (1978)

Survivors of out-of-hospital ventricular fibrillation (VF) are at high risk for recurrent VF, probably reflecting continued myocardial electrical instability. In this study 12-lead ECGs of 125 VF survivors with coronary heart disease were examined and compared to those of 98 ambulatory post-MI patients. The study was part of an effort to define clinical identifiers of patients likely to develop sudden cardiac death. Ventricular fibrillation survivors were commonly had premature ventricular complexes (PVCs):30% versus 13% (P less than 0.01). In addition, ECGs of VF survivors showed a significantly greater prevalence of ST-segment depression (46% versus 10%), T wave flattening (52% versus 26%), and QTc prolongation (35% versus 18%). It is proposed that these repolarization abnormalities represent asynchronous repolarization, which together with frequent PVCs, may set the stage for re-entrant ventricular dysrhythmias and ultimately VF. It is also possible that repolarization abnormalities together with prema...
Alterations of myocardial blood flow associated with experimental canine left ventricular hypertrophy secondary to valvular aortic stenosis.
Authors: DAlyono, R WAnderson, D GParrish, X ZDai, R JBache
Journal: Circulation Research (1986)

Experimental renovascular hypertension or supravalvular aortic constriction results in left ventricular hypertrophy and impaired minimum coronary vascular resistance. However, these experimental models expose the coronary arteries to increased intra-arterial pressure, so that hypertensive vascular changes might be responsible for the impaired minimum coronary resistance. This study was performed to test the hypothesis that left ventricular hypertrophy in the absence of increased coronary pressure results in abnormalities of myocardial perfusion. Aortic valve stenosis was produced by plication of the noncoronary aortic cusp of 11 dogs at 6-8 weeks of age. Studies were carried out when the animals reached adulthood; mean left ventricular:body weight ratio was 7.1 +/- 0.4 as compared to 4.4 +/- 0.3 g/kg in 11 normal dogs (P less than 0.01). Under quiet resting conditions, myocardial blood flow measured with microspheres was significantly greater than normal in dogs with aortic stenosis. However, during maxim...
MTSplice predicts effects of genetic variants on tissue-specific splicing
Authors: Jun Cheng, Muhammed Hasan Çelik, Anshul Kundaje, Julien Gagneur
Journal: Genome biology (2021)

Abstract We develop the free and open-source model Multi-tissue Splicing (MTSplice) to predict the effects of genetic variants on splicing of cassette exons in 56 human tissues. MTSplice combines MMSplice, which models constitutive regulatory sequences, with a new neural network that models tissue-specific regulatory sequences. MTSplice outperforms MMSplice on predicting tissue-specific variations associated with genetic variants in most tissues of the GTEx dataset, with largest improvements on brain tissues. Furthermore, MTSplice predicts that autism-associated de novo mutations are enriched for variants affecting splicing specifically in the brain. We foresee that MTSplice will aid interpreting variants associated with tissue-specific disorders.
Covid-19: Ivermectin’s politicisation is a warning sign for doctors
Authors: Bibi-Aisha Wadvalla
Journal: BMJ (2021)

The drug ivermectin has divided the medical community in South Africa and elsewhere, with some arguing it can both prevent and treat covid-19. <b>Bibi-Aisha Wadvalla</b> explains how the case encapsulates the central argument: do doctors or scientists know best?
Electrophysiological mechanisms underlying rate-dependent changes of refractoriness in normal and segmentally depressed canine Purkinje fibers. The characteristics of post-repolarization refractoriness.
Authors: J MDavidenko, CAntzelevitch
Journal: Circulation Research (1986)

Tissues from diseased hearts are known to exhibit post-repolarization refractoriness and rate-dependent changes of the refractory period that are often inconsistent with changes in action potential duration. To examine the electrophysiological mechanisms responsible for such rate-dependent changes of the refractory period, a narrow inexcitable zone was created by superfusing the central segments of Purkinje fibers with an ion-free isotonic sucrose solution. The degree of conduction impairment could be finely regulated by varying the resistance of the extracellular shunt pathway. At intermediate or low levels of block, the refractory period remained unchanged or decreased, respectively, as the rate was increased. At relatively high levels of block, however, we observed marked increases of the refractory period in response to increases in the stimulation rate. The disparity of refractoriness between normally conducting fibers and fibers exhibiting discontinuous conduction characteristics and post-repolari...
Recanalization of an acutely occluded aortocoronary bypass by intragraft fibrinolysis.
Authors: PRentrop, HBlanke, K RKarsch, HKostering, HOster, HLeitz
Journal: Circulation (1980)

Acute thrombotic occlusion of an aortocoronary bypass graft to the left anterior descending coronary artery (LAD) was successfully dissolved by selective infusion of streptokinase into the graft at 2000 U/min for 1 hour via catheter. There was partial recanalization of the graft and complete filling of the LAD within 15 minutes. After 1 hour of lysis, the graft was completely patent, although high-degree narrowing at the site of the proximal anastomosis was still present. Follow-up angiography 16 days later revealed persistent patency of the graft and disappearance of narrowing at the site of proximal anastomosis. The relatively low total dose of streptokinase (140,000 U) did not result in a systemic hyperlytic state. There were no complications. The technique may prove useful in acute graft occlusion but needs further evaluation.
The effects of daily exercise on susceptibility to sudden cardiac death.
Authors: G EBillman, P JSchwartz, H LStone
Journal: Circulation (1984)

The purpose of this study was to investigate the effects of daily exercise on susceptibility to sudden cardiac death. A 2 min coronary occlusion was initiated during the last minute of an exercise stress test and continued for 1 min after cessation of exercise in chronically instrumented dogs with a healed anterior wall myocardial infarction. Thirteen dogs developed ventricular fibrillation (VF; susceptible), while five did not (resistant). Before the exercise plus ischemia test, the baroreflex was evaluated with a bolus injection of phenylephrine (10 micrograms/kg). The changes in heart rate caused by a 30 mm Hg increase in systolic arterial pressure as well as the slopes of either heart rate or RR interval plotted against systolic arterial pressure were significantly lower in dogs that developed VR (resistant, -49.6 +/- 7.8; susceptible, -15.3 +/- 6.4 beats/min; p less than .001). Four resistant and eight susceptible animals were then placed on a 6 week daily exercise program, while eight susceptible do...
Intercapillary distance and capillary reserve in hypertrophied rat hearts beating in situ.
Authors: LHenquell, C LOdoroff, C RHonig
Journal: Circulation Research (1977)

Functional intercapillary distance (ICD) was measured in stop-motion photomicrographs of hypertrophied, normally compensated, well oxygenated rat hearts beating in situ. Left ventricular hypertrophy was produced by salt loading and unilateral nephrectomy. Minimum ICD (when all capillaries are open) also was measured. Ventricular weight increased by 30-40% within 8-9 weeks after nephrectomy. To compare the effect of normal and pathological growth, ICD was also measured in normal rats. In normal animals, minimum ICD and functional ICD increased linearly and proportionately with left ventricular weight. Consequently, the extent to which capillary recruitment could decrease ICD was the same in large and small normal hearts (about 2 micrometer). In the hypertrophied hearts, capillary recruitment could have maintained ICD within normal limits at rest for several weeks. After 8-9 weeks, however, the capillary reserve in hypertrophy was fully utilized at rest, and mean functional ICD was 1.5-2.0 micrometer greate...
Arterial Stiffness and Cardiovascular Risk in Hypertension
Authors: Pierre Boutouyrie, Phil Chowienczyk, Jay D. Humphrey, Gary F. Mitchell
Journal: Circulation Research (2021)

Arterial stiffness, a leading marker of risk in hypertension, can be measured at material or structural levels, with the latter combining effects of the geometry and composition of the wall, including intramural organization. Numerous studies have shown that structural stiffness predicts outcomes in models that adjust for conventional risk factors. Elastic arteries, nearer to the heart, are most sensitive to effects of blood pressure and age, major determinants of stiffness. Stiffness is usually considered as an index of vascular aging, wherein individuals excessively affected by risk factor exposure represent early vascular aging, whereas those resistant to risk factors represent supernormal vascular aging. Stiffness affects the function of the brain and kidneys by increasing pulsatile loads within their microvascular beds, and the heart by increasing left ventricular systolic load; excessive pressure pulsatility also decreases diastolic pressure, necessary for coronary perfusion. Stiffness promotes inward remodeling of small arteries, which increases resistance, blood pressure, and in turn, central artery stiffness, thus creating an insidious feedback loop. Chronic antihypertensive treatments can reduce stiffness beyond passive reductions due to decreased blood pressure. Preventive drugs, such as lipid-lowering drugs and antidiabetic drugs, have additional effects on stiffness, independent of pressure. Newer anti-inflammatory drugs also have blood pressure independent effects. Reduction of stiffness is expected to confer benefit beyond the lowering of pressure, although this hypothesis is not yet proven. We summarize different steps for making arterial stiffness measurement a keystone in hypertension management and cardiovascular prevention as a whole.