1,236 research outputs found

    Pancreatic transplantation at the University of Pittsburgh.

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    Campath-1H preconditioning with tacrolimus monotherapy is an effective immunosuppressive regimen for pancreas transplantation, with acceptable patient and graft survival rates early after transplantation. Rejection rates are low under this protocol if the tacrolimus level is kept consistently >10 ng/ml. This immunosuppressive protocol, combined with recent technical refinements, has resulted in lower rates of thrombosis and overall complications. Pancreatic transplantation en-bloc with visceral grafts has the following unique features: Diabetes is a rare indication, and HLA matching is not required. The gland is immunologically protected by the simultaneously transplanted visceral organs. Disease gravity, surgical complexity and gut alloimmunity influence the overall pancreatic allograft survival. The current UNOS listing criteria and data registry should be modified for obvious logistic and scientific reasons

    Epstein Barr Virus-positive large T-cell lymphoma presenting as acute appendicitis 17 years after cadaveric renal transplant: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>The majority of post-transplant lymphoproliferative disorders in renal transplant patients are of the B-cell phenotype, while the T-cell phenotype is rare. We report a case of Epstein Barr Virus-positive, T-cell lymphoma in a renal transplant patient, presenting unusually as acute appendicitis.</p> <p>Case presentation</p> <p>A 45-year-old Hispanic male renal transplant patient presented with right-side abdominal pain 17 years after transplant. The laboratory studies were unremarkable. Laparoscopic exploration showed an inflamed appendix so a laparoscopic appendectomy was performed. Pathology of the appendix showed large cells positive for CD3, CD56 and Epstein Barr Virus-encoded RNA staining, and negative for CD20 and CD30. The tissue tested positive for T-cell receptor gene rearrangement by polymerase chain reaction analysis. Treatment management involved reduction of immunosuppression and initiation of chemotherapy with cisplatin, etoposide, gemcitabine, and solumedrol followed by cyclophosphamide, hydroxydaunorubicin, vincristine and prednisone). He recovered and the allo-grafted kidney is fully functional.</p> <p>Conclusion</p> <p>We report a rare case of post-renal transplant large T-cell lymphoma, with an unusual presentation of acute appendicitis and Epstein Barr Virus-positivity, which responded well to chemotherapy.</p

    Alternative Mechanisms for Tn5 Transposition

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    Bacterial transposons are known to move to new genomic sites using either a replicative or a conservative mechanism. The behavior of transposon Tn5 is anomalous. In vitro studies indicate that it uses a conservative mechanism while in vivo results point to a replicative mechanism. To explain this anomaly, a model is presented in which the two mechanisms are not independent—as widely believed—but could represent alternate outcomes of a common transpositional pathway

    Early Antiretroviral Therapy reduces the incidence of otorrhea in a randomized study of early and deferred antiretroviral therapy: Evidence from the Children with HIV Early Antiretroviral Therapy (CHER) Study

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    <p>Abstract</p> <p>Background</p> <p>Although otorrhea occurs commonly in HIV-infected infants, there are few data. We compared the incidence of otorrhea in infants receiving early vs deferred ART in the Children with HIV Early Antiretroviral (CHER) trial. Infants aged 6 to 12 weeks of age with confirmed HIV infection and a CD4 percentage greater than or equal to 25% were randomized to early or deferred ART at two sites in South Africa. Medical records from one study site were reviewed for otorrhea.</p> <p>Findings</p> <p>Data were reviewed from the start of the trial in July 2005 until 20 June 2007, when the Data Safety Monitoring Board recommended that randomization to the deferred arm should stop and that all infants in this arm be reviewed for commencing antiretroviral therapy. Infants entered the study at a median of 7.4 weeks of age. Eleven of 38 (29%) on deferred therapy and 7 of 75 (9%) in the early-therapy group developed otorrhea (risk ratio 3.1, 95% confidence interval (CI) 1.31-7.36; p = 0.01).</p> <p>Conclusions</p> <p>Early initiation of antiretroviral therapy is associated with significantly less otorrhea than when a deferred strategy is followed.</p> <p>Trial registration</p> <p><a href="http://www.clinicaltrials.gov/ct2/show/NCT00102960">NCT00102960</a>. ClinicalTrials.Gov</p

    On the effects of mechanical stress of biological membranes in modeling of swelling dynamics of biological systems

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    We highlight mechanical stretching and bending of membranes and the importance of membrane deformations in the analysis of swelling dynamics of biological systems, including cells and subcellular organelles. Membrane deformation upon swelling generates tensile stress and internal pressure, contributing to volume changes in biological systems. Therefore, in addition to physical (internal/external) and chemical factors, mechanical properties of the membranes should be considered in modeling analysis of cellular swelling. Here we describe an approach that considers mechanical properties of the membranes in the analysis of swelling dynamics of biological systems. This approach includes membrane bending and stretching deformations into the model, producing a more realistic description of swelling. We also discuss the effects of membrane stretching on swelling dynamics. We report that additional pressure generated by membrane bending is negligible, compared to pressures generated by membrane stretching, when both membrane surface area and volume are variable parameters. Note that bending deformations are reversible, while stretching deformation may be irreversible, leading to membrane disruption when they exceed a certain threshold level. Therefore, bending deformations need only be considered in reversible physiological swelling, whereas stretching deformations should also be considered in pathological irreversible swelling. Thus, the currently proposed approach may be used to develop a detailed biophysical model describing the transition from physiological to pathological swelling mode.National Aeronautics & Space Administration (NASA):80NSSC19M0049; PR Space Grant (NASA):NNX15AI11Hinfo:eu-repo/semantics/publishedVersio

    ALC: automated reduction of rule-based models

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    <p>Abstract</p> <p>Background</p> <p>Combinatorial complexity is a challenging problem for the modeling of cellular signal transduction since the association of a few proteins can give rise to an enormous amount of feasible protein complexes. The layer-based approach is an approximative, but accurate method for the mathematical modeling of signaling systems with inherent combinatorial complexity. The number of variables in the simulation equations is highly reduced and the resulting dynamic models show a pronounced modularity. Layer-based modeling allows for the modeling of systems not accessible previously.</p> <p>Results</p> <p>ALC (Automated Layer Construction) is a computer program that highly simplifies the building of reduced modular models, according to the layer-based approach. The model is defined using a simple but powerful rule-based syntax that supports the concepts of modularity and macrostates. ALC performs consistency checks on the model definition and provides the model output in different formats (C MEX, MATLAB, <it>Mathematica </it>and SBML) as ready-to-run simulation files. ALC also provides additional documentation files that simplify the publication or presentation of the models. The tool can be used offline or via a form on the ALC website.</p> <p>Conclusion</p> <p>ALC allows for a simple rule-based generation of layer-based reduced models. The model files are given in different formats as ready-to-run simulation files.</p
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