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21.
Voltage-gated K+ channels undergo a voltage-dependent conductance change that plays a key role in modulating cellular excitability. While the Open state is captured in crystal structures of Kv1.2 and a chimeric Kv1.2/Kv2.1 channel, the Close state and the mechanism of this transition are still a subject of debate. Here, we propose a model based on mutagenesis combined with measurements of both ionic and gating currents which is consistent with the idea that the Open state is the default state, the energy of the electric field being used to keep the channel closed. Our model incorporates an 'Activated state' where the bulk of sensor movement is completed without channel opening. The model accounts for the well characterized electrophysiology of the 'V2' and 'ILT' mutations in Shaker, where sensor movement and channel opening occur over distinct voltage ranges. Moreover, the model proposes relatively small protein rearrangements in going from the Activated to the Open state, consistent with the rapid transitions observed in single channel records of Shaker type channels at zero millivolts. 相似文献
22.
Cardiac MRI in the management of congenital heart disease in children, adolescents, and young adults
Woodard PK Bhalla S Javidan-Nejad C Bierhals A Gutierrez FR Singh GK 《Current treatment options in cardiovascular medicine》2008,10(5):419-424
Recent advances in MRI have made this modality an important tool for evaluating heart disease. Faster scanning techniques, high spatial resolution, lack of ionizing radiation, lack of dependence on contrast material, and capability for functional imaging have made it an emerging noninvasive diagnostic tool with great potential in younger patients with heart disease. This article discusses the role of cardiac MRI, methods of evaluation, and newer application of MRI in evaluating congenital heart disease in pediatric and young adult patients. 相似文献
23.
Cardiac catheterization through ipsilateral radial and ulnar artery access during the same procedure
Dilip Kumar Madhumanti Panja Ashesh Halder Soumya Patra Arindam Pande Sanjeev Salil Kumar Mukherjee Rana Rathor Roy Ejaz Ahmad Bari Anil Kumar Singhi 《Indian heart journal》2021,73(3):387-388
We evaluated the safety and feasibility of ipsilateral radial and ulnar artery cannulation during the same catheterization procedure. Crossover from radial to femoral was done in 122 patients. Both ipsilateral radial and ulnar catheterization were performed in 16 patients without any complications, which was further supported by Doppler ultrasonography. 相似文献
24.
Jae-Jin Cho Brigid Joseph Baljit Singh Sappal Ranjit K Giri Richard Wang John W Ludlow Mark E Furth Robert Susick Sanjeev Gupta 《Liver international》2004,24(4):361-370
BACKGROUND: The availability of well-characterized human liver cell populations that can be frozen and thawed will be critical for cell therapy. We addressed whether human hepatocytes can recover after cryopreservation and engraft in immunodeficient mice. METHODS: We isolated cells from discarded human livers and studied the properties of cryopreserved cells. The viability of thawed cells was established with multiple in vitro assays, including analysis of liver gene expression, ureagenesis, cytochrome P450 activity, and growth factor-induced cell proliferation. The fate of transplanted cells was analysed in immunodeficient NOD-SCID mice. RESULTS: After thawing, the viability of human hepatocytes exceeded 60%. Cells attached to culture dishes, proliferated following growth factor stimulation and exhibited liver-specific functions. After transplantation in NOD-SCID mice, cells engrafted in the peritoneal cavity, a heterologous site, as well as the liver itself, retained hepatic function and proliferated in response to liver injury. Transplanted hepatocytes were integrated in the liver parenchyma. Occasionally, transplanted cells were integrated in bile ducts. CONCLUSIONS: Cryopreserved human liver cell showed the ability to retain functional integrity and to reconstitute both hepatic and biliary lineages in mice. These studies offer suitable paradigms aimed at characterizing liver cells prior to transplantation in people. 相似文献
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Lévy Samuel Steinbeck Gerhard Santini Luca Nabauer Michael Maceda Diego Penela Kantharia Bharat K. Saksena Sanjeev Cappato Riccardo 《Journal of interventional cardiac electrophysiology》2022,65(1):287-326
Journal of Interventional Cardiac Electrophysiology - Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice. The aim of this review was to evaluate the... 相似文献
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Hsu LC Ali SR McGillivray S Tseng PH Mariathasan S Humke EW Eckmann L Powell JJ Nizet V Dixit VM Karin M 《Proceedings of the National Academy of Sciences of the United States of America》2008,105(22):7803-7808
NOD2, a NOD-like receptor (NLR), is an intracellular sensor of bacterial muramyl dipeptide (MDP) that was suggested to promote secretion of the proinflammatory cytokine IL-1beta. Yet, the molecular mechanism by which NOD2 can stimulate IL-1beta secretion, and its biological significance were heretofore unknown. We found that NOD2 through its N-terminal caspase recruitment domain directly binds and activates caspase-1 to trigger IL-1beta processing and secretion in MDP-stimulated macrophages, whereas the C-terminal leucine-rich repeats of NOD2 prevent caspase-1 activation in nonstimulated cells. MDP challenge induces the association of NOD2 with another NLR protein, NALP1, and gel filtration analysis revealed the formation of a complex consisting of NOD2, NALP1, and caspase-1. Importantly, Bacillus anthracis infection induces IL-1beta secretion in a manner that depended on caspase-1 and NOD2. In vitro, Anthrax lethal toxin strongly potentiated IL-1beta secretion, and that response was NOD2 and caspase-1-dependent. Thus, NOD2 plays a key role in the B. anthracis-induced inflammatory response by being a critical mediator of IL-1beta secretion. 相似文献
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Nonpharmacological therapy for malignant ventricular arrhythmias: Implantable defibrillator trials 总被引:2,自引:0,他引:2
Sanjeev Saksena Gunter Breithardt Paul Dorian H. Leon Greene Nandini Madan Michael Block 《Progress in cardiovascular diseases》1996,38(6):429-444
Implantable cardioverter-defibrillators (ICDs) are an important nonpharmacological option in the treatment of malignant ventricular arrhythmias. Technological advances in current devices permit nonthoracotomy implantation with transvenous lead systems using biphasic shocks. Decreasing device size has resulted in pectoral implantation. Battery longevity is still short in comparison with that of pacemakers. Lead failure rates as well as pacing thresholds are significantly higher than those for cardiac pacing lead systems. Other complications of ICD systems include infection, perforation, and thrombosis. The long-term performance of nonthoracotomy lead systems for ICD devices has now been extensively studied. Sudden death recurrence rates for these systems are less than 2% in 3 years and less than 5% at 5 years. Clinical trials with both monophasic and biphasic systems show a high degree of prevention of sudden death. Comparison of ICD outcome with that of drug therapy in three large retrospective studies and two small prospective randomized trials favors improved survival and sudden death prevention with device therapy. However, these studies need corroboration from large prospective trials. Two large prospective trials, CIDS and the AVID study, are now in progress to address this issue. 相似文献