Publications by authors named "Karwande S"

Systemic allergic reaction to a percutaneous patent foramen ovale (PFO) occlusion device is a rare event with only scattered reports in the literature. Serious allergic reactions to these devices have a poorly defined incidence, presentation, and natural history. We present a woman with a previously unknown nickel allergy who developed severe chest pain beginning the morning after percutaneous device closure of the PFO.

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Background: Tricuspid valve insufficiency (TI) is common after orthotopic heart transplantation. However, tricuspid valve replacement or repair (TVR) is rare. The aim of this study is to evaluate our experience with TVR in cardiac transplant recipients.

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Transforming growth factor-beta1 (TGF-beta1) is abundantly expressed in pulmonary hypertension, but its effect on the pulmonary circulation remains unsettled. We studied the consequences of TGF-beta1 stimulation on freshly isolated human pulmonary artery smooth muscle cells (HPASMC). TGF-beta1 initially promoted differentiation, with upregulated expression of smooth muscle contractile proteins.

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Pulmonary vein tumours are rare. They can cause significant morbidity and mortality. The present report discusses a rare case of pulmonary vein sarcoma in an elderly male patient.

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Direct cerebral revascularization is an important procedure in the treatment of certain complex aneurysms and skull base tumors when acute sacrifice of the internal carotid artery is required. It likely remains an appropriate treatment in a small subgroup of patients with cerebral ischemia refractory to maximal medical management. Similar to cardiovascular surgery, the choice of a graft conduit is critical for a successful outcome.

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Background: Development of myocardial preservation solutions requires the use of whole organ models which are animal and labor intensive. These models rely on physiologic rather than biochemical endpoints, making accurate comparison of the relative efficacy of individual solution components difficult. We hypothesized that myocardial slices could be used to assess preservation of biochemical function during cold storage.

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Background: Chronic lung allograft rejection, commonly manifest as obliterative bronchiolitis (OB/BOS), hinders long-term survival after lung transplantation (LT). OB/BOS is traditionally treated with augmented immunosuppression and results in short-term stabilization in pulmonary function for most patients. However, peribronchiolar fibroproliferation and airway obstruction usually recur despite initial improvements seen with increases in immunosuppression.

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Background: Vascular endothelial growth factor (VEGF) plays an important role in angiogenesis. We hypothesized that a combination of recombinant angiogenic proteins might induce myocardial VEGF production and cause a shift in the mRNA signal produced.

Materials And Methods: The left ventricles of New Zealand white rabbits were injected with 500 microL of saline, basic fibroblast growth factor (bFGF), platelet-derived growth factor-AB (PDGF(AB)), platelet-derived growth factor-BB (PDGF(BB)), bFGF + PDGF(AB), or bFGF + PDGF(BB).

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Background: Osteoporotic fracture is a significant source of morbidity after lung transplantation. Therapies to prevent posttransplant fracture are largely untested among lung transplant recipients.

Methods: In this prospective uncontrolled study, lung transplant referrals were assessed for bone health with metabolic, radiographic, and bone mineral density measurements.

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Background: In this study we examine whether conversion from a didactic lecture format to a resident self-study and presentation program can improve performance on the Thoracic Surgery In-Training Examination (TSITE).

Methods: During the first 5 years, educational conferences were didactic lectures delivered by the attending thoracic surgery staff (group 1, n = 9 residents). During the second 5 years, residents prepared and delivered reviews from major textbook sources (group 2, n = 9 residents).

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Background: Cardiopulmonary bypass (CPB) may contribute to the complications and cost of coronary artery bypass grafting (CABG). Off-pump CABG (OPCAB) allows coronary revascularization without CPB. We hypothesized that OPCAB provides satisfactory graft patency while reducing complications and cost compared with CABG with CPB.

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Background: Surgical resection of the larynx, hypopharynx and cervical esophagus, or pharyngolaryngoesophagectomy (PLE), with pharyngogastric anastomosis (PGA) offers a means of controlling local and regional carcinoma of the upper aerodigestive tract (UADT). We reviewed our experience with PLE for carcinoma of the UADT to evaluate functional outcome and survival.

Methods: Patients undergoing PLE from 1986 through 1999 were reviewed.

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Interleukin-18 (IL-18) and IL-12 have been shown to play an important role in the induction of interferon-gamma (IFN-gamma). IFN-gamma induces the proliferation of T cells and natural killer (NK) cells and augments the Th1 immune cascade. The role of IL-18 and IL-12 in the induction of IFN-gamma following allogeneic heart transplantation has not been described.

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Background: Development of lung preservation solutions typically requires whole-organ models which are animal and labor intensive. These models rely on physiologic rather than biochemical endpoints, making accurate comparison of the relative efficacy of individual solution components difficult. We hypothesized that lung slices could be used to assess preservation of biochemical function during cold storage.

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We present a patient with rupture of both atrioventricular valves in a previously healthy adult man who sustained a 5-foot fall. The mechanism of injury was such that it would not necessarily raise an adequate index of suspicion for valvular damage had valvular rupture not occurred. The usefulness of perioperative echocardiography is highlighted.

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Objective: Inflammatory cytokines, particularly tumor necrosis factor, contribute to myocardial dysfunction after ischemia-reperfusion injury. Aprotinin may improve outcomes in cardiac surgery through suppression of inflammatory mediators. We hypothesized that aprotinin may exert its beneficial effects through suppression of tumor necrosis factor alpha.

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Background: Transfusion of cellular blood products during left ventricular assist device (LVAD) implantation has been associated with HLA allosensitization, resulting in the need for a negative prospective cross-match and prolonged transplant waiting times. In order to prevent this risk, we developed a protocol to avoid transfusion of cellular blood products.

Methods: The protocol included preoperative patient stabilization, perioperative recombinant erythropoietin and blood conservation strategies, and postoperative monitoring of mixed venous oxygen saturation (SVO2) to assure adequate peripheral oxygen delivery.

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The molecular mechanisms by which endothelin (ET)-1 induces pulmonary hypertension are poorly understood. We investigated the effects of ET-1 on outward K+ currents of normoxic and chronically hypoxic human pulmonary arterial (PA) smooth muscle cells (HPSMCs). In normoxic HPSMCs, ET-1 has dual effects.

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We investigated the effects of chronic hypoxia on the major outward K+ currents in early cultured human main pulmonary arterial smooth muscle cells (HPSMC). Unitary currents were measured from inside-out, outside-out, and cell-attached patches of HPSMC. Chronic hypoxia depolarized resting membrane potential (Em) and reduced the activity of a charybdotoxin (CTX)- and iberiotoxin-sensitive, Ca2+-dependent K+ channel (KCa).

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Background: Short-term studies suggest that cardiac transplant immunosuppression without maintenance corticosteroids is feasible in selected patients. However, concern exists as to the long-term effects, specifically the possibility of increased morbidity and mortality because of late allograft rejection and allograft coronary artery disease.

Methods: We retrospectively reviewed the records from 441 consecutive heart transplantation procedures done in 416 patients with use of an immunosuppressive protocol that attempted corticosteroid withdrawal within 2 months of transplantation.

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In this study, using whole cell and single-channel configurations of the patch-clamp technique, we characterized K+ currents (IK) in cultured human pulmonary arterial smooth muscle cells. The net whole cell outward membrane current (IKo) was activated at potentials positive to -60 mV. One component of IKo, IK(dr), was inhibited by 4-aminopyridine (4-AP) and high concentrations of tetraethylammonium (TEA) but was Ca2+ and charybdotoxin (CTX) insensitive.

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