Characterization of a hyperpolarization-activated time-dependent potassium current in canine cardiomyocytes from pulmonary vein myocardial sleeves and left atrium

Abstract Background The ablation targets of atrial fibrillation (AF) are adjacent to bronchi and pulmonary arteries (PAs). We used computed tomography (CT) to evaluate the anatomical correlation between left atrium (LA)-pulmonary vein (PV) and adjacent structures. Methods Data were collected from 126 consecutive patients using coronary artery CT angiography. The LA roof was divided into three layers and nine points. The minimal spatial distances from the nine points and four PV orifices to the adjacent bronchi and PAs were measured. The distances from the PV orifices to the nearest contact points of the PVs, bronchi, and PAs were measured. Results The anterior points of the LA roof were farther to the bronchi than the middle or posterior points. The distances from the nine points to the PAs were shorter than those to the bronchi (5.19 ± 3.33 mm vs 8.62 ± 3.07 mm; P < .001). The bilateral superior PV orifices, especially the right superior PV orifices were closer to the PAs than the inferior PV orifices (left superior PV: 7.59 ± 4.14 mm; right superior PV: 4.43 ± 2.51 mm; left inferior PV: 24.74 ± 5.26 mm; right inferior PV: 22.33 ± 4.75 mm) (P < .001). Conclusions The right superior PV orifices were closer to the bronchi and PAs than other PV orifices. The ablation at the mid-posterior LA roof had a higher possibility to damage bronchi. CT is a feasible method to assess the anatomical adjacency in vivo, which might provide guidance for AF ablation.

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Metastatic renal cell carcinoma extending to the left atrium through the inferior pulmonary vein

Interactive Cardiovascular and Thoracic Surgery ◽

10.1093/icvts/ivab018 ◽

2021 ◽

Author(s):

Alan G Dawson ◽

Cathy J Richards ◽

Leonidas Hadjinikolaou ◽

Apostolos Nakas

Keyword(s):

Renal Cell Carcinoma ◽

Cell Carcinoma ◽

Left Atrium ◽

Pulmonary Vein ◽

Metastatic Renal Cell Carcinoma ◽

Renal Cell ◽

Pulmonary Veins ◽

Lower Lobe ◽

Inferior Pulmonary Vein ◽

The Right

Abstract Metastatic renal cell carcinoma with involvement through the pulmonary veins to the left atrium is very rare. We report the case of a 70-year-old male with metastatic renal cell carcinoma to the right lower lobe of the lung abutting the inferior pulmonary vein with extension to the left atrium without pre-operative evidence. Surgical resection was achieved through a posterolateral thoracotomy. Lung masses that abut the pulmonary veins should prompt further investigation with a pre-operative transoesophageal echocardiogram to minimize unexpected intraoperative findings.

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Successful Surgical Treatment of a Giant Pulmonary Vein Ewing's Sarcoma Invading Left Atrium

Archivos de Bronconeumología (English Edition) ◽

10.1016/j.arbr.2019.12.031 ◽

2021 ◽

Vol 57 (8) ◽

pp. 542

Author(s):

F. Javier González-García ◽

José Joaquín Domínguez del Castillo ◽

Ángel Salvatierra Velázquez

Keyword(s):

Surgical Treatment ◽

Left Atrium ◽

Pulmonary Vein ◽

Ewing’S Sarcoma ◽

Ewing's Sarcoma

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Characterization of the A‐type potassium current in murine gastric antrum

The Journal of Physiology ◽

10.1113/jphysiol.2002.025171 ◽

2002 ◽

Vol 544 (2) ◽

pp. 417-428 ◽

Cited By ~ 30

Author(s):

Gregory C. Amberg ◽

Salah A. Baker ◽

Sang Don Koh ◽

William J. Hatton ◽

Keith J. Murray ◽

...

Keyword(s):

Potassium Current ◽

Gastric Antrum

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Study of the Characteristics of the Pulmonary Vein and Superior Vena Cava of Rabbits

Journal of Biomaterials and Tissue Engineering ◽

10.1166/jbt.2021.2585 ◽

2021 ◽

Vol 11 (1) ◽

pp. 112-122

Author(s):

Pan Wang ◽

Xin-Chun Yang ◽

Xiu-Lan Liu ◽

Rong-Feng Bao ◽

Huai-Yu Ding ◽

...

Keyword(s):

Action Potential ◽

Pulmonary Vein ◽

Refractory Period ◽

Potassium Current ◽

Superior Vena ◽

Vena Cava ◽

Current Intensity ◽

Left And Right ◽

The Difference ◽

Right Atria

Background: This study aims to (1) investigate the characteristics of the action potential and triggering activity of cardiomyocytes in the pulmonary vein (PV) and superior vena cava (SVC) of rabbits and (2) study the features of cation currents in cardiomyocytes in rabbit PV and SVC-inward rectifier potassium current (IK1), transient outward potassium current (Ito), and non-selective cation currents (INSCC). Methods: The standard glass microelectrode and whole-cell patch-clamp techniques were used to record the action potential and various currents in the above cells. Results: (1) Cardiomyocytes in either PV or SVC had longer action potential durations than in the adjacent atrium, and spontaneous early after depolarization (EAD) could occur in both PV and SVC under normal physiological conditions. (2) The action potential in PV cardiomyocytes had a relative refractory period but did not have an absolute refractory period, and this characteristic enabled a premature beat that triggered a second plateau response, which led to EAD. (3) INSCC was found for the first time in the PV, SVC, and atria. (4) The current intensity of IK1, Ito, and INSCC was significantly lower in the PV and SVC than in the left and right atria, and the difference in the current intensity in INSCC could influence the action potential. Conclusions: PV and SVC can both initiate and maintain AF, but PV is the primary ectopic foci in initiating AF. The present study found that the second plateau response was easily induced in cardiomyocytes in PA shortly after depolarization. This was a specific characteristic of the action potential of PV. In addition, we preliminarily analyzed the differences in the main outward currents and noted a voltage-dependent INSCC in both PV and SVC rabbits’ cardiomyocytes. Furthermore, the current intensities of IK1, Ito, and INSCC were significantly lower in the PV and SVC than in the left and right atria, and the difference in the current intensity of INSCC influenced the action potential. The different permeability of INSCC for cations at different phases may play a role in inducing EAD.

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Oxypeucedanin is a mechanism-based inactivator of CYP2B6 and CYP2D6

Current Drug Metabolism ◽

10.2174/1389200222666210629114830 ◽

2021 ◽

Vol 22 ◽

Author(s):

Kehan Zhang ◽

Yilin Li ◽

Yao Fu ◽

Tiantian Cui ◽

Qian Wang ◽

...

Keyword(s):

Pain Relief ◽

Liver Microsomes ◽

Reactive Intermediates ◽

Enzyme Inactivation ◽

Time Dependent ◽

Reactive Metabolites ◽

Angelica Dahurica ◽

Dependent Inhibition ◽

Microsomal Incubation

Background: Herbal medicine Angelica dahurica is widely employed for the treatment of rheumatism and pain relief in China. Oxypeucedanin is a major component of the herb. Objectives : The objectives of this study are aimed at the investigation of mechanism-based inactivation of CYP2B6 and CYP2D6 by oxypeucedanin, characterization of the reactive metabolites associated with the enzyme inactivation, and identification of the P450s participating in the bioactivation of oxypeucedanin. Methods : Oxypeucedanin was incubated with liver microsomes or recombinant CYPs2B6 and 2D6 under designed conditions, and the enzyme activities were measured by monitoring the generation of the corresponding products. The resulting reactive intermediates were trapped with GSH and analyzed by LC-MS/MS. Results : Microsomal incubation with oxypeucedanin induced a time-, concentration-, and NADPH-dependent inhibition of CYPs2B6 and 2D6 with kinetic values of KI/kinact 1.82 µM/0.07 min-1 (CYP2B6) and 8.47 µM/0.044 min-1 (CYP2D6), respectively. Ticlopidine and quinidine attenuated the observed time-dependent enzyme inhibitions. An epoxide and/or γ-ketoenal intermediate(s) derived from oxypeucedanin was/were trapped in microsomal incubations. CYP3A4 was the primary enzyme involved in the bioactivation of oxypeucedanin. Conclusion : Oxypeucedanin was a mechanism-based inactivator of CYP2B6 and CYP2D6. An epoxide and/or γ-ketoenal intermediate(s) may be responsible for the inactivation of the two enzymes.

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