tbuckley/cabot-search huggingface dataset:
"Supernormal conduction" of a premature impulse utilizing the fast pathway in a patient with dual atrioventricular nodal pathways.
Authors: PDenes, C RWyndham, DWu, K MRosen
Journal: Circulation (1975)

Electrophysiological studies with atrial extrastimulus technique suggested the presence of dual atrioventricular (A-V) nodal pathways in a patient with hypothyroidism, as evidenced by a sudden increase of H1-H2 intervals at critical A1-A2 coupling intervals. Following the atrial extrastimulus (A2), a third impulse (A3) occurred spontaneously. During slow pathway conduction of A2, and A3, appearing at a critically timed interval allowed fast pathway conduction, resulting in an earlier than expected QRS (a form of supernormal conduction). This demonstration of fast pathway conduction during slow pathway conduction adds strong evidence for the existence of dual A-V nodal pathways.
Potentiation of coronary vasoconstriction by beta-adrenergic blockade in patients with coronary artery disease.
Authors: M JKern, PGanz, J DHorowitz, JGaspar, W HBarry, B HLorell, WGrossman, G HMudge
Journal: Circulation (1983)

Although beta-adrenergic blocking agents reduce myocardial oxygen consumption and symptoms of myocardial ischemia in patients with coronary artery disease (CAD), propranolol has been reported to exacerbate coronary artery spasm in some patients with variant angina. To determine whether increased coronary vasomotor tone can be induced by beta-adrenergic blockade, we measured the changes in coronary vascular resistance (CVR) during cold pressor testing (CPT) in 15 patients, nine with severe CAD and six with normal left coronary anatomy, before and after i.v. propranolol (0.1 mg/kg). Coronary blood flow was measured by coronary sinus thermodilution. CVR was calculated as mean arterial pressure divided by coronary sinus blood flow. Heart rate was maintained constant at a paced subanginal rate of 95 +/- 5 beats/min. Before propranolol, CPT induced significant increases in coronary vascular resistance in patients with CAD (15.0 +/- 2.2%, p less than 0.02), but no increase in CVR in the normal patients. After pr...
The risk of advanced heart block in surgical patients with right bundle branch block and left axis deviation.
Authors: J OPastore, P MYurchak, K MJanis, J DMurphy, L MZir
Journal: Circulation (1978)

The risk of advanced atrioventricular block during anesthesia was studied prosepctively in 44 patients with right bundle branch block and left axis deviation who underwent a total of 52 operations over a 14 month period. All patients had continuous electrocardiographic monitoring throughout anesthesia induction, operation, and surgical recovery. Of the 52 operative procedures, 24 were done under general anesthesia, 11 under spinal, and 17 under local. The preoperative cardiac rhythms were atrial fibrillation in two patients, atrial tachycardia with block in one patient, atrial flutter in one patient, and sinus rhythm in the remaining patients. Temporary pacemakers were inserted preoperatively in six patients, usually because of PR interval prolongation on the preoperative electrocardiogram. There was only one episode of transient complete heart block in 51 of the 52 operative procedures. In two of the six patients with temporary pacemakers, significant pacer-related ventricular irritability occurred. This...
Effective arterial elastance as index of arterial vascular load in humans.
Authors: R PKelly, C TTing, T MYang, C PLiu, W LMaughan, M SChang, D AKass
Journal: Circulation (1992)

BACKGROUNDThis study tested whether the simple ratio of ventricular end-systolic pressure to stroke volume, known as the effective arterial elastance (Ea), provides a valid measure of arterial load in humans with normal and aged hypertensive vasculatures.METHODS AND RESULTSVentricular pressure-volume and invasive aortic pressure and flow were simultaneously determined in 10 subjects (four young normotensive and six older hypertensive). Measurements were obtained at rest, during mechanically reduced preload, and after pharmacological interventions. Two measures of arterial load were compared: One was derived from aortic input impedance and arterial compliance data using an algebraic expression based on a three-element Windkessel model of the arterial system [Ea(Z)], and the other was more simply measured as the ratio of ventricular end-systolic pressure to stroke volume [Ea(PV)]. Although derived from completely different data sources and despite the simplifying assumptions of Ea(PV), both Ea(Z) and Ea(PV)...
Effects of calcium on shortening velocity in frog chemically skinned atrial myocytes and in mechanically disrupted ventricular myocardium from rat.
Authors: P AHofmann, R LMoss
Journal: Circulation Research (1992)

Effects of [Ca2+] on isometric tension and unloaded shortening velocity were characterized in single chemically skinned myocytes from frog atrium and in mechanically disrupted myocardium from rat ventricle. The preparations were attached to a force transducer and piezoelectric translator and were viewed with an inverted microscope to allow continuous monitoring of sarcomere length during mechanical measurements. Unloaded shortening velocity was determined by measuring the time required to take up various amounts of slack imposed at one end of each preparation. Ca2+ sensitivity of isometric tension was assessed as pCa50, i.e., the Ca2+ concentration at which tension was 50% maximal, and was greater for frog atrial myocytes (pCa50 6.17) than for rat ventricular myocytes (pCa50 6.06). This difference in Ca2+ sensitivity may be due to variations in myofibrillar protein isoform composition in the two preparations. Inclusion of caffeine in the activating solutions substantially increased the Ca2+ sensitivity of...
Enhanced renal prostaglandin production in the dog. The effect of sodium arachidonate in nonfiltering kidney.
Authors: J GGerber, J LData, A SNies
Journal: Circulation Research (1978)

Sodium arachidonate, 10(-5) g/kg per minute, was infused into the renal artery of a nonfiltering canine kidney in situ in order to determine the effects of enhanced prostaglandin synthesis on renal blood flow and its distribution in circumstances where prostaglandins produced in the medulla could not gain access to the cortex via tubular fluid. The contralateral normal kidney was also infused with sodium arachidonate and served as control. Radioactive microspheres were used to calculate the hemodynamic effects. In the nonfiltering kidney, the total renal blood flow increased after sodium arachidonate from a mean of 105 ml/min per 100 g to 146 ml/min per 100 g (P less than 0.01). This increase was completely abolished by prior treatment with indomethacin, 8 mg/kg, intravenously. The normal kidney responded qualitatively the same as the nonfiltering side. In both kidneys, blood flow increased significantly to all cortical zones except the outermost (zone 1), but the fractional distribution of renal blood fl...
Persistence and dynamics of fluorescent <i>Lactobacillus plantarum</i> in the healthy <i>versus</i> inflamed gut
Authors: Sophie Salomé-Desnoulez, Sabine Poiret, Benoit Foligné, Ghaffar Muharram, Véronique Peucelle, Frank Lafont, Catherine Daniel
Journal: Gut Microbes (2021)

The gastrointestinal tract is the main ecological niche in which Lactobacillus strains may provide health benefits in mammals. There is currently a need to characterize host-microbe interactions in space and time by tracking these bacteria in vivo. We combined noninvasive whole-body imaging with ex vivo fluorescence confocal microscopy imaging to monitor the impact of intestinal inflammation on the persistence of orally administered Lactobacillus plantarum NCIMB8826 in healthy and inflamed mouse colons. We developed fluorescent L. plantarum strains and demonstrated that mCherry is the best system for in vivo imaging and ex vivo fluorescence confocal microscopy of these bacteria. We also used whole-body imaging to show that this anti-inflammatory, orally administered strain persists for longer and at higher counts in the inflamed colon than in the healthy colon. We confirmed these results by the ex vivo confocal imaging of colons from mice with experimental colitis for 3 days after induction. Moreover, extended orthogonal view projections enabled us to localize individual L. plantarum in sites that differed for healthy versus inflamed guts. In healthy colons, orally administered bacteria were localized in the lumen (in close contact with commensal bacteria) and sometimes in the crypts (albeit very rarely in contact with intestinal cells). The bacteria were observed within and outside the mucus layer. In contrast, L. plantarum bacteria in the inflamed colon were mostly located in the lumen and (in less inflamed areas) within the mucus layer. In more intensely inflamed areas (i.e., where the colon had undergone structural damage), the L. plantarum were in direct contact with damaged epithelial cells. Taken as a whole, our results show that fluorescently labeled L. plantarum can be used to study the persistence of these bacteria in inflamed guts using both noninvasive whole-body imaging and ex vivo fluorescence confocal microscopy.
Arterial hemodynamics in human hypertension. Effects of adrenergic blockade.
Authors: C TTing, C YChou, M SChang, S PWang, B NChiang, F CYin
Journal: Circulation (1991)

BACKGROUNDResistance, pulse wave velocity, and wave reflections have been shown to be increased in patients with essential hypertension compared with normotensive controls. These alterations are completely normalized by nitroprusside infusion but exacerbated during beta-adrenergic blockade, suggesting an enhanced smooth muscle tone that is in part modulated by adrenergically mediated vasodilation. The present study was performed to examine the extent to which this apparently enhanced smooth muscle tone is a result of alpha-adrenergically mediated vasoconstriction.METHODS AND RESULTSAge-matched normotensive and hypertensive Chinese subjects were instrumented with catheter-tipped micromanometers and an electromagnetic flow velocity sensor positioned in the ascending aorta. Aortic impedance and wave reflection properties were obtained from Fourier analysis of the pressure and flow signals during baseline conditions, after beta-blockade with propranolol (0.15 mg/kg i.v.), and after alpha-blockade with intrave...
Origin of the atrial electrogram recorded from the esophagus.
Authors: E NPrystowsky, E LPritchett, J JGallagher
Journal: Circulation (1980)

The purpose of this study was to ascertain the origin of the atrial electrogram recorded on the esophageal lead. The atria and esophagus were mapped during reciprocating tachycardia in 11 patients with the Wolff-Parkinson-White syndrome and one patient with atrioventricular nodal reentry, and during right ventricular pacing in four additional patients. The esophagus was mapped by recording atrial electrograms at 1-cm intervals throughout the esophagus beginning at the most distal area where atrial depolarization was seen. The retrograde atrial activation time recorded on the esophageal lead in its distal position occurred at the same time as atrial septal depolarization in all patients. In 14 of 16 patients, the distal esophageal ventriculoatrial (VA) conduction time was also the shortest esophageal VA conduction time recorded. In two of five patients with left lateral accessory pathways, the shortest esophageal VA conduction time was noted during pullback of the lead from the esophagus instead of at the ...
Selective dye and ionic permeability of gap junction channels formed by connexin45.
Authors: R DVeenstra, H ZWang, E CBeyer, P RBrink
Journal: Circulation Research (1994)

Gap junctions are thought to mediate the direct intercellular coupling of adjacent cells by the gating of an aqueous pore permeable to ions and molecules of up to 1 kD or 8 to 14 A in diameter. We performed ion-substitution and dye-transfer experiments to determine the relative Cl-/K+ conductance and dye permeability of anionic fluorescein derivatives in chick connexin45 (Cx45) channels. We demonstrate that Cx45 forms a 26 +/- 6-picosiemen (pS) channel with a maximum detectable Cl- permeability of 0.2 relative to K+ or Cs+. Although homogeneous channel conductances were observed in multichannel recordings, the open probability estimates were indicative of nonhomogeneous gating behavior and occasional cooperativity. A second conductance state of 19 +/- 4 pS begins to predominate at higher voltages. Cx45 gap junctions are permeable to 2',7'-dichlorofluorescein but are not permeable to the more polar 6-carboxyfluorescein dye. These observations suggest that the Cx45 pore diameter is approximately 10 A and is...
Covid-19: Certifying status for “vaccine passports” must not increase GPs’ workload, says Royal College
Authors: Abi Rimmer
Journal: BMJ (2021)

Thank you for your interest in spreading the word about The BMJ.NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address. Username * Your Email * Send To * You are going to email the following Covid-19: Certifying status for “vaccine passports” must not increase GPs’ workload, says Royal College Your Personal Message CAPTCHA This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Magnetic resonance jet velocity mapping in mitral and aortic valve stenosis.
Authors: P JKilner, C CManzara, R HMohiaddin, D JPennell, M GSutton, D NFirmin, S RUnderwood, D BLongmore
Journal: Circulation (1993)

BACKGROUNDMagnetic resonance (MR) phase-shift velocity mapping is an established method for measurement of nonturbulent intravascular flow. Shortening the echo time of the MR sequence to 3.6 msec allowed application of the technique to turbulent jet flow. The objective of this study was validation of MR jet velocity mapping in patients with cardiac valve stenosis.METHODS AND RESULTSWe used a 0.5-T Picker MR machine to measure peak poststenotic jet velocity in 15 consecutive patients recruited with known valve disease (six mitral stenosis, three of these restudied after valvoplasty, and 11 aortic stenosis). On the same day as the MR study, these patients underwent independent Doppler echocardiographic measurement of peak jet velocity. The results of 10 further MR investigations of aortic stenosis are also reported and compared with Doppler studies performed within 6 months. Of the 29 MR studies, 28 (97%) produced interpretable velocity maps, the one failure being attributed to misplacement of the imaging s...
Impact of Endoscopic Duodenal and Ampullary Resection in Fap Patients: Spigelman Classification can be Considered as Outdated Even in Stage III and IV
Authors: M Belhassine, E Pérez-Cuadrado Robles, K Dahan, D Leonard, A Kartheuser, H Dano, PH Deprez
Journal: Endoscopy (2021)

Aims In familial adenomatous polyposis (FAP) a dedicated endoscopic surveillance with endoscopic resection (ER) of duodenal and ampullary lesions has been proposed by the European guidelines. The Spigelman classification (SC) is used to define surgical indications in patients with advanced duodenal disease. Aims: describe the impact of ER in patients with FAP and the role played by SC.
Graded global ischemia and reperfusion. Cardiac function and lactate metabolism.
Authors: C SApstein, LDeckelbaum, MMueller, LHagopian, W BHood
Journal: Circulation (1977)

The effect of global ischemia of different degrees of severity and reperfusion was studied in the isolated working rat heart. Four degrees of ischemia were induced by reducing the control total coronary flow of 8 ml/min to 0, 0.04, 0.4, or 0.8 ml/min for 30 minutes, after which the coronary flow was returned to the control level. After severe ischemia (0 and 0.04 ml/min ischemic coronary flow groups), recovery of contractility was to less than 30% of the control, pre-ischemic value of ventricular developed pressure and dP/dt, and irreversible cardiac contracture and an increased pacing threshold occurred. After moderate ischemia (0.4 and 0.8 ml/min ischemic coronary flow groups), contractile function recovered completely, ischemic contracture was rapidly reversible and the pacing threshold did not increase. The moderately ischemic groups were able to function at a stable, low level of contractility for the 30 minute ischemic period, whereas the severely ischemic groups had no contractile activity. The amo...
Modulation of evoked contractions in rat arteries by ryanodine, thapsigargin, and cyclopiazonic acid.
Authors: HShima, M PBlaustein
Journal: Circulation Research (1992)

The contribution of sarcoplasmic reticulum (SR) Ca2+ release to evoked tension in rat arterial rings was studied by comparing the effects of ryanodine (an SR Ca2+ channel opener) and thapsigargin and cyclopiazonic acid (CPA) (two Ca(2+)-ATPase inhibitors). Isometric tension was evoked by serotonin (5-HT), 30-50 mM external K+, and 10 mM caffeine in rings of aorta and a small (second-order) branch of the superior mesenteric artery (SMA). Resting tension was unaffected by 10 microM ryanodine or 1-5 microM thapsigargin, but 20 microM CPA raised resting tension in aortic rings and evoked spontaneous contractions in some SMA rings. Ryanodine (10 microM) or 1-5 microM thapsigargin partially depleted the SR Ca2+ stores (indicated by reduced caffeine-evoked contractions) and attenuated 5-HT- and high K(+)-evoked contractions in aortic rings but augmented 5-HT- and high K(+)-evoked contractions in SMA. Caffeine completely emptied the SR Ca2+ stores in the presence of ryanodine but not thapsigargin in both the aort...
Transient outward current carried by potassium and sodium in quiescent atrioventricular node cells of rabbits.
Authors: TNakayama, HIrisawa
Journal: Circulation Research (1985)

Single atrioventricular node cells were dispersed by treating the rabbit heart with collagenase. In Tyrode's solution, the cells became rounded, and about 20% of them showed spontaneous activity, whereas the rest remained quiescent. When those quiescent cells were whole-cell clamped, depolarizing clamp pulses from the holding potential of -83 mV induced an outward current which decayed quickly, with a time course similar to that of the transient outward current in the Purkinje fiber. The amplitude of the current became larger when progressively more positive clamp pulses were given from a very negative holding potential. The inactivation time course of this current consisted of two exponential components. Single-channel current recordings from those cells revealed a class of channels that activated more frequently during the initial part of depolarizing pulses. Summation of those unitary currents reproduced activation and inactivation time courses of the macroscopic current well, suggesting that this chan...
False-Positive 68Ga–Fibroblast Activation Protein-Specific Inhibitor Uptake of Benign Lymphoid Tissue in a Patient With Breast Cancer
Authors: Cihan Gündoğan, Yunus Güzel, Canan Can, Ulaş Alabalik, Halil Kömek
Journal: Clinical Nuclear Medicine (2021)

Abstract 68 Ga-fibroblast activation protein-specific inhibitor (FAPI)-04 PET/CT was performed in a patient with left lower outer quadrant breast cancer who had 18 F-FDG PET/CT imaging. 68 Ga-FAPI-04 PET/CT showed higher accumulation of radiotracer in primary tumor and axillary lymph nodes than 18 F-FDG PET/CT. In addition, focal increased FAPI uptake was observed in another nodular lesion in the lower inner quadrant in the same breast, which was considered malignant. However, Tru-Cut biopsy of this lesion was reported as benign lymphoid tissue. This case showed that all FAPI accumulation in breast tissue should not be interpreted in favor of malignancy; histopathological confirmation is required.
Heterotopic cardiac transplantation decreases the capacity for rat myocardial protein synthesis.
Authors: IKlein, A MSamarel, RWelikson, CHong
Journal: Circulation Research (1991)

Heterotopic cardiac isografts are vascularly perfused hearts that maintain structural and functional integrity for prolonged periods of time. When placed in an infrarenal location, the heart is hemodynamically unloaded and undergoes negative growth, leading to cardiac atrophy. At 7 and 14 days after transplantation, the transplanted heart was decreased in size compared with the in situ heart (p less than 0.001). To assess the possible mechanism(s) to account for this reduction in size we studied in vivo rates of total left ventricular (LV) protein synthesis, total LV RNA content, and 18S ribosomal RNA content by nucleic acid hybridization. The LV protein synthetic rate was 4.7 and 5.3 mg/day in the in situ heart and was significantly decreased to 2.9 and 2.7 mg/day in the transplanted hearts at 7 and 14 days, respectively. LV RNA content of the transplant declined to 53% and 48% of the in situ value at 7 and 14 days, respectively. Hybridization studies revealed that LV 18S ribosomal subunit content was re...
l-cysteine-modified chiral gold nanoparticles promote periodontal tissue regeneration
Authors: Shuang Zhang, Hong Zhou, Na Kong, Zezheng Wang, Huangmei Fu, Yangheng Zhang, Yin Xiao, Wenrong Yang, Fuhua Yan
Journal: Bioactive Materials (2021)

Gold nanoparticles (AuNPs) with surface-anchored molecules present tremendous potential in tissue regeneration. However, little is known about chiral-modified AuNPs. In this study, we successfully prepared L/D-cysteine-anchored AuNPs (L/D-Cys-AuNPs) and studied the effects of chiral-modified AuNPs on osteogenic differentiation and autophagy of human periodontal ligament cells (hPDLCs) and periodontal tissue regeneration. In vitro, more L-Cys-AuNPs than D-Cys-AuNPs tend to internalize in hPDLCs. L-Cys-AuNPs also significantly increased the expression of alkaline phosphatase, collagen type 1, osteocalcin, runt-related transcription factor 2, and microtubule-associated protein light chain 3 II and decreased the expression of sequestosome 1 in hPDLCs compared to the expression levels in the hPDLCs treated by D-Cys-AuNPs. In vivo tests in a rat periodontal-defect model showed that L-Cys-AuNPs had the greatest effect on periodontal-tissue regeneration. The activation of autophagy in L-Cys-AuNP-treated hPDLCs may be responsible for the cell differentiation and tissue regeneration. Therefore, compared to D-Cys-AuNPs, L-Cys-AuNPs show a better performance in cellular internalization, regulation of autophagy, cell osteogenic differentiation, and periodontal tissue regeneration. This demonstrates the immense potential of L-Cys-AuNPs for periodontal regeneration and provides a new insight into chirally modified bioactive nanomaterials.
The cortisol response during heart-lung bypass.
Authors: K MTaylor, J VJones, M SWalker, SRao, W HBain
Journal: Circulation (1976)

The response patterns of plasma cortisol and plasma free cortisol have been studied in 20 consecutive patients undergoing cardiac surgery involving the use of heart-lung bypass. Sixteen consecutive patients undergoing closed mitral valvotomy have been used as controls. Total plasma cortisol levels fell at the onset of extracorporeal circulation (ECC) and did not rise significantly throughout the period of ECC. The peak cortisol level in the bypass patients occurred at 24 hours postoperatively with elevated levels still present at 48 hours. This pattern was significantly different from the control patients (P less than 0.001) who exhibited the typical cortisol stress response pattern. Synthetic ACTH stimulation of the adrenal cortex during heart-lung bypass produced a positive response (i.e., a rise in plasma cortisol greater than 7.5 mug/100 ml) in all six patients studied while the six mitral valvotomy patients had no response to synthetic ACTH administration during operation (P less than 0.01). Plasma f...
冠動脈分岐部病変の治療としての同時kissing baloon法の適切なバルーン径を測定するための機能的公式―volumetric intravascular untrasound分析による臨床的評価―
Authors: Morino Yoshihiro, Yamamoto Hirosada, Mitsudo Kazuaki, Nagaoka Masakazu, Takeuchi Hiroki, Okamoto Nami, Kozuma Kumiko, Matsuzaki Atsushi, Tanabe Kengo, Hara Kazuhiro, Tanabe Teruhisa, Ikari Yuji
Journal: Circulation (2008)