Distribution and function of sodium channel subtypes in human atrial myocardium.

Voltage-gated sodium channels composed of a pore-forming α subunit and auxiliary β subunits are responsible for the upstroke of the action potential in cardiac muscle. However, their localization and expression patterns in human myocardium have not yet been clearly defined. We used immunohistochemical methods to define the level of expression and the subcellular localization of sodium channel α and β subunits in human atrial myocytes.

Low-gradient aortic valve stenosis myocardial fibrosis and its influence on function and outcome.

Objectives: This prospective cohort study in patients with aortic stenosis (AS) aimed to identify surrogates of myocardial fibrosis that are easy to derive in clinical practice, allow the differentiation of low-gradient severe AS from moderate AS, and have an impact on clinical outcome.

Background: In patients with symptomatic aortic AS, a characteristic subgroup (i.e.

Donor antigen-specific regulatory T-cell function affects outcome in kidney transplant recipients.

Chronic transplant dysfunction, a major impediment to long-term allograft survival, is caused by several factors including an ongoing alloimmune response termed chronic rejection. To define some of these factors further, we selected 107 patients mismatched to their donors from 623 patients transplanted at a single center. Patients were categorized according to their immunosuppressive treatment and further divided into those with stable or chronic allograft dysfunction.

Inhibition of nuclear translocation of calcineurin suppresses T-cell activation and prevents acute rejection of donor hearts.

Background: Inhibition of calcineurin (CnA) activity by cyclosporine A (CsA) is the mainstay in immunosuppressive therapy. CsA inhibits the phosphatase activity of the cytosolic phosphatase CnA and, therefore, prevents the dephosphorylation and subsequently nuclear translocation of the transcription factor nuclear factor of activated T cells (NFAT). However, CsA has multiple other targets within the cell and is, therefore, not specific.

Cardiac surgery and hematologic malignancies: a retrospective single-center analysis of 56 consecutive patients.

Objective: Patients with a history of hematologic malignancies (HMs) are considered high-risk candidates for cardiac surgery. Increased perioperative rates of infections, thrombo-embolic complications, and bleeding disorders are reported. However, low patient numbers and lack of control groups limit all published studies.

Hemodynamic assessment of severe aortic stenosis: MRI evaluation of dynamic changes of vena contracta.

Purpose: Direct magnetic resonance imaging (MRI) planimetry of the maximal systolic aortic valve area does not consider temporal variations of the opening area during the ejection period. We evaluated an MRI-based methodology for the assessment of valvular dynamics in patients with severe aortic stenosis by measuring the systolic variability of the valvular blood stream, that is, the "vena contracta."

Materials And Methods: With institutional review board approval, we examined 22 patients (13 male, 9 female; mean age, 68 ±10 years) with severe aortic stenosis using 1.

Cardiac operations in the presence of meningioma.

Background: We investigated the effect of concomitant intracranial meningiomas on perioperative and postoperative complications after cardiac operations. Also studied was the intraoperative and perioperative management and long-term outcome of such patients.

Methods: We retrospectively evaluated 16 cardiac surgical patients with intracranial meningiomas between January 1996 and July 2007.

Impact of myocardial fibrosis in patients with symptomatic severe aortic stenosis.

Background: In this prospective follow-up study, the effect of myocardial fibrosis on myocardial performance in symptomatic severe aortic stenosis was investigated, and the impact of fibrosis on clinical outcome after aortic valve replacement (AVR) was estimated.

Methods And Results: Fifty-eight consecutive patients with isolated symptomatic severe aortic stenosis underwent extensive baseline characterization before AVR. Standard and tissue Doppler echocardiography and cardiac magnetic resonance imaging (late-enhancement imaging for replacement fibrosis) were performed at baseline and 9 months after AVR.

Regulatory allospecific T cell clones abrogate chronic allograft rejection.

True alloantigen-specific tolerance is the ultimate goal of solid organ transplantation, eliminating the need for long-term immunosuppression. Recent evidence suggests that Th1-derived cytokines are associated with rejection and Th2-derived cytokines with long-term allograft survival, but the roles of these subsets in rejection and tolerance are incompletely understood. Here, we analyzed the functional and regulatory capacities of T cell clones derived from tolerant and rejecting rats (Wistar rat donors, Lewis rat recipients).

Heterotopic rat heart transplantation (Lewis to F344): early ICAM-1 expression after 8 hours of cold ischemia.

Background: Primary graft dysfunction is a still poorly understood complication after cardiac transplantation. Ischemia/reperfusion injury contributes to different disorders resulting in impaired graft function.

Methods: In a heterotopic rat heart transplantation model we extended graft ischemic time up to 8 hours.

Cardiac allograft vasculopathy after cardiac transplantation and hormone therapy: positive effects?

Background: There is a great deal of controversy surrounding the issue of hormone replacement therapy after transplantation. The question whether or not this therapy has effects in cardiac allograft vasculopathy (CAV), the Achilles heel of cardiac transplantation or other unique aspects of allograft function is still unknown.

Methods: We investigated the long-term effect of 17beta-estradiol as well as phytoestrogen Coumestrol, a synthetically produced phytoestrogen, on the development of CAV and the degree of fibrosis in an ovariectomized female heterotopic chronic allograft model (LEW-F344).

Formation of 4-hydroxy-2-nonenal protein adducts in the ischemic rat heart after transplantation.

Background: Free radicals formed during ischemia and reperfusion can lead to lipid peroxidation (LPO) and the formation of 4-hydroxy-2-nonenal (4-HNE), one of the most toxic products of LPO. Using a heterotopic rat heart transplantation model we investigated endogenous 4-HNE formation as a response to cold storage of the transplant and warm blood reperfusion in the recipient.

Methods: Lewis rat hearts were subjected to 30, 240 or 480 minutes of 4 degrees C cold ischemia in Bretschneider cardioplegic solution without or with transplantation and 240-minute reperfusion in F344 recipients.

Heterotopic rat heart transplantation: severe loss of glutathione in 8-hour ischemic hearts.

Background: Tissue damage caused by reactive oxygen species (ROS) formed during ischemia/reperfusion seems to be an important risk factor in the failure of transplanted hearts. Although endogenous anti-oxidants protect the myocardium against free radical attack under physiologic conditions, their capacity may become limited during severe oxidative stress. Thus, we investigated the effect of 8-hour cold ischemia on the myocardial anti-oxidative defense system in a heterotopic rat heart transplantation model.