tbuckley/cabot-search huggingface dataset:
Evidence for a distinct gap-junctional phenotype in ventricular conduction tissues of the developing and mature avian heart.
Authors: R GGourdie, C RGreen, N JSevers, R HAnderson, R PThompson
Journal: Circulation Research (1993)

The gap-junctional proteins connexin43 and connexin42 have been shown to be expressed in the developing and mature avian heart, but their respective spatiotemporal distributions are unknown. In the present study, we have immunolocalized connexin42 in the conduction tissues of the adult avian heart (nonbranching bundle, bundle branches, and Purkinje fibers) and vascular endothelial cells. Connexin43 immunolabeling was confined to vascular smooth muscle. A novel microwave-based method was used to label connexin42 and connexin43 in the same tissue section. Neither connexin42 nor connexin43 was immunolocalized in working myocardium, atrioventricular node, and atrioventricular ring tissue of the bird heart. Although connexin42 first appeared in periarterial conduction myocytes and vascular endothelium at 9-10 embryonic days, the central conduction tissues, including the nonbranching bundle and proximal branches, remained immunonegative for connexin42 up until hatching (approximately 20 embryonic days). During ...
Ionic mechanisms of electronic inhibition and concealed conduction in rabbit atrioventricular nodal myocytes.
Authors: YLiu, WZeng, MDelmar, JJalife
Journal: Circulation (1993)

BACKGROUNDThe term   is used in electrocardiography when a proximal (atrial or ventricular) impulse penetrates the atrioventricular (AV) node but fails to traverse it completely. Its penetration into the node is inferred by its after effects on the propagation of succeeding impulses. Concealed AV nodal conduction is a well-established phenomenon, but its precise cellular and subcellular mechanisms are unknown. It has been suggested that concealed conduction results from a transient impairment of excitability caused by the subthreshold depolarization (ie, electrotonic inhibition) that is elicited downstream of the site of block.METHODS AND RESULTSWe studied the ionic mechanism of electrotonic inhibition and concealed conduction in single myocytes isolated from the rabbit AV node. Cells were paced using just-threshold current pulses delivered at a constant (basic) cycle length of 1 second. Appropriately timed interpolation of a conditioning pulse of depolarizing but subthreshold current...
Commentary: Team perspective
Authors: Saroj Kumar Das, Devdatta Sarwate, J K Mordani, K J Ng, Mark Nel
Journal: BMJ (2006)

Mr Mahon's case raises several questions and shows the controversy that often accompanies attempts to define the best management of a complex clinical problem.1 His initial presentation with a left sided varicocele and a small right sided hydrocele had triggered investigation with ultrasonography. Although varicoceles have been reported in 0.6-11% of patients with renal cell carcinoma,2 they are also common in the general population. The cost effectiveness of routine ultrasonography is therefore questionable, although it should be considered in a patient with rapid onset of varicocele.

Mr Mahon is nevertheless fortunate that he had ultrasonography because it also detected a large abdominal aortic aneurysm. His obesity makes it likely that the aneurysm would have remained undetected. Ultrasonography is a potentially important tool for mass screening and surveillance of abdominal aortic aneurysms, and the multicentre aneurysm screening study has shown that screening is cost effective in high risk populations.3 Elective abdominal aortic aneurysm repair is associated with a less than 5% overall mortality risk, whereas mortality in the case of ruptured aortic aneurysm is around 50-80%.
AAPOR Reporting Guidelines for Survey Studies
Authors: Susan C. Pitt, Todd A. Schwartz, Danny Chu
Journal: JAMA Surgery (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 Surgery HomeNew OnlineCurrent IssueFor Authors Podcast Publications JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry (1919-1959) JN Learning / CMESubscribeJobsInstitutions / LibrariansReprints & Permissions Terms of Use | Privacy Policy | Accessibility Statement 2023 American Medical Association. All Rights Reserved Search All JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Forum Archive JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry Input Search Term Sign In Individual Sign In Sign inCreate an Account Access through your institution Sign In Purchase Options: Buy this article Rent this article Subscribe to the JAMA Surgery journal
High energy phosphate stores and lactate levels in different layers of the canine left ventricle during reactive hyperemia.
Authors: R BDunn, K MMcDonough, D MGriggs
Journal: Circulation Research (1979)

To study postischemic recovery of myocardial energy metabolism in relation to the reactive hyperemic response, the tissue levels of creatine phosphate (CP), adenosine triphosphate (ATP), and lactate were estimated in the outer, middle, and inner layers of the left ventricle before, during, and at several times after a 20-second bilateral coronary arterial occlusion in the open-chest dog. The reactive hyperemic response was characterized by monitoring blood flow in the cannulated coronary sinus in a separate group of dogs. Substantial changes in myocardial CP and lactate, but not ATP, were produced by the occlusion and reciprocal transmural gradients in CP and lactate occurred such that CP was lowest and lactate was highest in the inner layer. Recovery of high energy phosphate stores (CP + ATP) occurred long before blood flow returned to the preocclusion level, this being achieved in two of the three layers after completion of only 29% of the reactive hyperemic response when the blood flow debt repayment w...
The incidence and clinical significance of epicardial late potentials in patients with recurrent sustained ventricular tachycardia and coronary artery disease.
Authors: M EJosephson, M BSimson, A HHarken, L NHorowitz, R AFalcone
Journal: Circulation (1982)

Seventy-eight patients with ventricular tachycardia associated with coronary artery disease underwent intraoperative mapping while in sinus rhythm to evaluate the frequency and significant of late potentials. In 30 of these patients, the surface ECG was subjected to signal averaging to correlate the incidence and duration of low-amplitude, delayed electrograms with the presence of late potentials recorded during epicardial mapping. One to four epicardial late potentials were observed in nine patients (11.5%). These nine patients did not differ hemodynamically from patients without late potentials. In four patients, the site of epicardial breakthrough during ventricular tachycardia bore no relationship (i.e., greater than 3 cm away) to the late potential or the site of origin of the tachycardia. In the five other patients with late potentials, epicardial breakthrough and site of origin of ventricular tachycardia were closely related to the free wall of an apical aneurysm. However, three of these patients h...
Impaired Contraction (Retraction) of Blood Clots Is a Possible Pathogenic Mechanism in Venous Thromboembolism
Authors: Rustem I. Litvinov, Alina D. Peshkova, Dmitry V. Malyasyov, Roman A. Bredikhin, Giang Le Minh, Izabella A. Andrianova, Valerie Tutwiler, John W. Weisel
Journal: Blood (2017)
Enhanced donor screening for faecal microbial transplantation during COVID-19
Authors: Seema Nair Parvathy, John G Lenehan, Ricardo Fernandes, Susan M Poutanen, Susy Hota, Saman Maleki Vareki, Michael Silverman
Journal: Gut (2021)

high-risk procedure 5 due to aerosolisation and contact with infected bodily fluids (sputum, faecal matter and even bile 6 ), but linking transmission of SARS-CoV-2 to a previous endoscopic procedure is difficult, considering the large variation in both the incubation and viraemic periods.The authors did not account for the timing of endoscopy in relation to the moment of infection and/or admission.As shown by recent studies, viral load in patients with COVID-19 decreases substantially over a short period of time, 7 so even patients in critical condition might, in fact, have low viral loads when admitted to the endoscopy ward.Moreover, there is evidence that supports a rapid decline in infectivity after several days, 8 independent of viral load, 9 possibly justifying the lack of infectious isolates from the collected samples.In our own experience, there have been significant delays in access to endoscopy for patients with COVID-19 (data currently under review for publication), and this might, at least in part, account for the results of Boškoski et al.The findings of the study are reassuring, and we would like to point out that, even positive PCR findings would still not be enough to confirm infectivity since viral viability should be demonstrated by means of culture rather than PCR.Due to the significant impact of the SARS-CoV-2 on patient care, in-depth studies to establish clear correlations between viral load, infectivity and transmission risks are required to provide definitive answers in this matter.
Perivenous Stellate Cells Are the Main Source of Myofibroblasts and Cancer‐Associated Fibroblasts Formed After Chronic Liver Injuries
Authors: Shan‐Shan Wang, Xinyu Thomas Tang, Minghui Lin, Jia Yuan, Yi Jacky Peng, Xiujuan Yin, GuoGuo Shang, Gaoxiang Ge, Zhenggang Ren, Bo O. Zhou
Journal: Hepatology (2021)

Background and Aims Studies of the identity and pathophysiology of fibrogenic HSCs have been hampered by a lack of genetic tools that permit specific and inducible fate‐mapping of these cells in vivo . Here, by single‐cell RNA sequencing of nonparenchymal cells from mouse liver, we identified transcription factor 21 ( Tcf21 ) as a unique marker that restricted its expression to quiescent HSCs. Approach and Results Tracing Tcf21 + cells by Tcf21 ‐CreER (Cre‐Estrogen Receptor fusion protein under the control of Tcf21 gene promoter) targeted ~10% of all HSCs, most of which were located at periportal and pericentral zones. These HSCs were quiescent under steady state but became activated on injuries, generating 62%‐67% of all myofibroblasts in fibrotic livers and ~85% of all cancer‐associated fibroblasts (CAFs) in liver tumors. Conditional deletion of Transforming Growth Factor Beta Receptor 2 ( Tgfbr2 ) by Tcf21 ‐CreER blocked HSC activation, compromised liver fibrosis, and inhibited liver tumor progression. Conclusions In conclusion, Tcf21 ‐CreER–targeted perivenous stellate cells are the main source of myofibroblasts and CAFs in chronically injured livers. TGF‐β signaling links HSC activation to liver fibrosis and tumorigenesis.
Limb vascular responsiveness to beta-adrenergic receptor stimulation in patients with congestive heart failure.
Authors: M ACreager, R JQuigg, C JRen, M ARoddy, W SColucci
Journal: Circulation (1991)

BACKGROUNDIn patients with congestive heart failure, the chronotropic and inotropic responses to beta-adrenergic agonists are reduced. It is not known whether desensitization of peripheral beta-adrenoceptors accounts for impaired limb vasodilation in these patients. Accordingly, we studied 14 normal subjects and 13 age-matched patients with congestive heart failure.METHODS AND RESULTSTo distinguish vasodilation mediated by beta-adrenoceptors and adenylate cyclase from that mediated by stimulation of guanylate cyclase, each subject received intrabrachial artery infusions of isoproterenol (1-100 ng/min) and sodium nitroprusside (0.3-10 micrograms/min), respectively. Forearm blood flow was determined by venous occlusion plethysmography. Maximal vasodilative potential, determined during reactive hyperemia, was reduced in the patients with congestive heart failure. The maximal forearm blood flow response to isoproterenol was comparable in patients with heart failure and in normal subjects (8.0 +/- 1.1 versus 9...
Coronary angiogenesis during long-term hypertension and left ventricular hypertrophy in dogs.
Authors: R JTomanek, K ASchalk, M LMarcus, D GHarrison
Journal: Circulation Research (1989)

Many studies have documented that during the development of left ventricular hypertrophy (LVH) coronary vascular growth lags behind that of cardiac muscle. To ascertain whether significant growth of coronary resistance vessels occurs with long-standing hypertension and LVH, we studied dogs with Goldblatt (one-kidney, one-clip) hypertension seven months after surgery. Left ventricular minimal coronary vascular resistance (LV MCVR) was derived from adenosine-induced maximal flow measured with 15 microns microspheres. Morphometric data were based on perfuse-fixed hearts arrested in diastole. Hypertension and LVH were associated with a 46% increase in left ventricular weight/body weight ratio (LVH, 6.73 +/- 0.31; control, 4.62 +/- 0.30), no significant change in LV MCVR/100 g, and a reduction in total LV MCVR (LVH, 0.11 +/- 0.02 mm Hg/ml/min; control, 0.15 +/- 0.02 mm Hg/ml/min). Arterial and arteriolar wall/lumen ratios were virtually identical in the two groups. Arteriolar (lumen diameter less than 200 micr...
Increased oxygen cost of contractility in stunned myocardium of dog.
Authors: YOhgoshi, YGoto, SFutaki, HTaku, OKawaguchi, HSuga
Journal: Circulation Research (1991)

Recent studies have shown that myocardial oxygen consumption does not proportionally decrease with the deterioration of contractile function in stunned myocardium. To investigate this disproportion, we studied the end-systolic pressure-volume relation and the relation between oxygen consumption per beat (VO2) and systolic pressure-volume area (PVA, a measure of total mechanical energy) in stunned hearts. In the VO2-PVA relation, VO2 can be divided into PVA-dependent and PVA-independent fractions. In excised cross-circulated dog left ventricles, a 15-minute normothermic global ischemia followed by 60-120 minutes of reperfusion significantly decreased the ventricular contractility index (Emax) by approximately 40%, but the PVA-independent VO2 did not significantly decrease. Oxygen cost of PVA, defined as the slope of the VO2-PVA relation, was slightly decreased in stunned hearts. Restoration of the depressed Emax to the preischemic control level by calcium infusion increased the PVA-independent VO2 to 137 +...
Impaired prostaglandin E1/I2 receptor activity of human blood platelets in acute ischemic heart disease.
Authors: N NKahn, H SMueller, A KSinha
Journal: Circulation Research (1990)

The platelets from 74 patients with acute myocardial infarction or with unstable angina showed decreased prostaglandin E1/I2 receptor activity when compared with that of 56 normal volunteers by using [3H]prostaglandin E1 as a probe. In normals, Scatchard analyses showed the presence of one high-affinity-low-capacity (Kd1 = 9.0 +/- 1.2 nM [mean +/- SD]; n1 = 120 +/- 30 sites/cell) and one low-affinity-high-capacity (Kd2 = 1.1 +/- 0.5 microM; n2 = 1,460 +/- 250 sites/cell) prostaglandin E1/I2 receptor population in platelets. In contrast (p less than 0.01), platelets from patients showed decreased ligand binding (n1 = 40 +/- 20 sites/cell; n2 = 800 +/- 210 sites/cell) with little change in the affinity of the receptors (Kd1 = 7.50 +/- 1.6 nM; Kd2 = 0.68 +/- 0.24 microM). On the other hand, the platelets from the patients with dilated cardiomyopathy (n = 7) who were hospitalized for acute chest pain but had normal coronary arteries did not show any impairment of the receptor activity. The plasma prostacyclin...
Outcomes Of The Endoscopic Treatment In Biliary Panlithiasis
Authors: MK Temani, M Mahmoudi, S Bradai, A Khsiba, A Ben Mohamed, M Medhioub, L Hamzaoui, MM Azzouz
Journal: Endoscopy (2021)

Aims Biliary panlithiasis (BP) is defined by the presence of multiple lithiasis (more than 3) in the main bile duct (MDB). The aim of our work was to assess the rate of lithiasis extraction failure during BP and the associated factors.
Hemodynamic results of aortic valvular replacement with the porcine xenograft valve.
Authors: D CMorris, S BKing, J SDouglas, C WWickliffe, E LJones
Journal: Circulation (1977)

Twenty-three patients were evaluated by cardiac catheterization two to 12 months following aortic valve replacement with the porcine xenograft valve. These hemodynamic studies established a mean peak-to-peak systolic gradient across the prosthesis of 23 mm Hg with a range of 6-58 mm Hg. The mean effective orifice area was calculated to be 1.25 cm2. The effective orifice area increased with increasing valve size from 0.99 cm2 for the 19 mm prosthesis to 1.44 cm2 for the 25 mm prosthesis. While in general the hemodynamics of the porcine xenograft valve are comparable to other available prostheses, the exceedingly small orifice areas (0.99 cm2 and 1.03 cm2) calculated for the 19 mm and 21 mm prostheses render their use inadvisable.
Abnormal Clones of T Cells Producing Interleukin-5 in Idiopathic Eosinophilia
Journal: New England Journal of Medicine (1999)

Background The cause of persistent eosinophilia and the hypereosinophilic syndrome is unknown. Recent work suggests that in some patients with the hypereosinophilic syndrome, a clone of abnormal T cells produces large amounts of interleukin-5, a cytokine required for the growth and differentiation of eosinophils. We examined T-cell surface markers, rearranged T-cell–receptor genes, and in vitro production of cytokines by T cells from patients with idiopathic eosinophilia. Methods The expression of surface molecules on T cells was measured by flow cytometry. Cytokine expression was measured by enzyme-linked immunosorbent assay, flow cytometry, and immunohistochemical analysis. To identify dominant (clonal) rearrangements of the T-cell receptor within the lymphocyte population, Southern blot analysis ( b chain) and the polymerase chain reaction ( g chain) were performed according to standard protocols. Results Among 60 patients with idiopathic eosinophilia, 16 had circulating T cells with an aberrant immunophenotype. In each of these patients, the abnormal immunophenotype was unique. Evidence of clonal rearrangements of the T-cell receptor was obtained in 8 of the 16 patients. In most instances, the abnormal T cells expressed large amounts of surface proteins associated with T-cell activation (the a chain of the interleukin-2 receptor and the HLA-DR antigen). Moreover, the aberrant T cells produced large amounts of interleukin-5 in vitro. Conclusions Clonal populations of abnormal T cells producing interleukin-5 occur in some patients with idiopathic eosinophilia. (N Engl J Med 1999;341:1112-20.)
Prostaglandins mediate arteriolar dilation to increased blood flow velocity in skeletal muscle microcirculation.
Authors: AKoller, GKaley
Journal: Circulation Research (1990)

In cremaster muscle of pentobarbital-anesthetized rats, temporary occlusion of an arteriole increased red blood cell velocity (mean increase, 8.2 +/- 1.0 mm/sec from a control velocity of 7.9 +/- 0.7 mm/sec) in proximal parallel arteriolar branches (mean control diameter, 19.4 +/- 0.6 microns). Increases in flow velocity were consistently followed by proportional delayed (6-15 seconds) increases in arteriolar diameter (5.8 +/- 0.7 microns). Administration of NG-monomethyl-L-arginine (200 microM), an inhibitor of the synthesis of endothelium-derived relaxing factor that blocked the arteriolar responses to acetylcholine (1 microM) but not to arachidonic acid (10 microM), did not affect the dilation (mean increase, 8.9 +/- 1.1 microns) due to increases in red blood cell velocity (13.4 +/- 1.5 mm/sec). However, the cyclooxygenase inhibitor indomethacin (or meclofenamate), which completely blocked the dilator response to arachidonic acid but did not change the response to acetylcholine, inhibited the arteriola...
Effect of nontransmural necrosis on epicardial potential fields. Correlation with fiber direction.
Authors: SWatabe, BTaccardi, R LLux, P RErshler
Journal: Circulation (1990)

The effect of nontransmural necrosis on epicardial potential distributions was studied in 13 dogs. In previous studies, left ventricular epicardial pacing generated epicardial potential maps at QRS onset with a negative central area and two positive areas that faced the portions of the wavefront propagating along fibers. Subsequently, the positive areas expanded in a counterclockwise direction by 90 degrees to 120 degrees. In those studies, the rotatory expansion of the positive areas was tentatively attributed to the spread of excitation through deep myocardial layers, where fiber direction rotated counterclockwise from epicardium to endocardium. To test this hypothesis, we tried to interrupt the counterclockwise expansion of the positive area by creating localized, nontransmural necrosis at various depths in the left ventricular wall by injection of formalin or application of laser energy. Epicardial potential maps were obtained from a grid of 12 x 15 electrodes on a 44 x 56-mm area. Epicardial pacing f...
Migration of cultured vascular smooth muscle cells through a basement membrane barrier requires type IV collagenase activity and is inhibited by cellular differentiation.
Authors: R RPauly, APassaniti, CBilato, RMonticone, LCheng, NPapadopoulos, Y AGluzband, LSmith, CWeinstein, E GLakatta
Journal: Circulation Research (1994)

The migration of vascular smooth muscle cells (VSMCs) from the tunica media to the neointima is a key event in the development and progression of many vascular diseases and a highly predictable consequence of mechanical injury to the blood vessel. In vivo, VSMCs are surrounded by and embedded in a variety of extracellular matrices (ECMs) that must be traversed during migration. One of the principal barriers to cell movement in the intact vessel is the basement membrane (BM) that surrounds each VSMC and separates the VSMC-containing medial cell layer from the endothelium. We have used a Boyden chamber to monitor the ability of VSMCs to degrade a BM barrier as they migrate toward a chemoattractant and to define the role of extracellular proteases in this process. We show that cultured VSMCs can migrate across a BM barrier and that this ability was dependent on the phenotypic state of the cell. VSMCs maintained in a proliferating or synthetic state readily migrated across a BM toward a chemoattractant, whe...
Isolated drainage of the superior vena cava into the left atrium in a 52-year-old man: a rare congenital malformation in the adult presenting with cyanosis, polycythemia, and an unsuccessful lung scan.
Authors: M DEzekowitz, P OAlderson, B HBulkley, P NDwyer, LWatkins, D LLappe, H LGreene, L CBecker
Journal: Circulation (1978)

This report describes a 52-year-old black male with the isolated finding of an anomalous superior vena cava draining into the left atrium. The patient presented with dizziness, mild cyanosis, polycythemia and  cardiac and pulmonary findings. The first major diagnostic clue in this confusing clinical presentation was an unsuccessful lung perfusion scan in which intravenous tracer consistently bypassed the lungs. This appears to be the first adult presenting with this rare anomaly. This condition should be suspected if cyanosis, clubbing, and a normal cardiac examination coexist and if the more common pulmonary and hematological causes of this triad have been excluded.
76P Epithelial-to-mesenchymal transition circulating tumor cells subtype as a biomarker in resectable NSCLC
Authors: M.J. Moyano Rodriguez, C.I. Bayarri-Lara, D. De Miguel-Perez, P. Bravo-Carmona, A. Garcia-Diaz, M.J. Serrano-Fernandez
Journal: Journal of Thoracic Oncology (2021)