196,309 research outputs found
Emerging role of pharmacogenetic in organ transplantation
No full textThe currently used immunosuppressive drugs have a narrow therapeutic index which required to individualize
the dose regimen for different recipients. Pharmacogenetic is the use of genetic screening to prevent metabolic
responses to different immunosuppressive drugs. Since the oxidative enzymes cytochrome P450 CYP3A and the
drug efflux pump P-glycoprotein (P-gp) play a pivotal role in immunosuppressive drugs metabolism, pharmacogenetic
studies have been mainly focused on these two enzymes. This would provide an important aid toward drug regimen
individualization during the post-transplant therapy and has potential to improve graft outcome
Spectral Analysis of the Biharmonic Operator Subject to Neumann Boundary Conditions on Dumbbell Domains
No full textWe consider the biharmonic operator subject to homogeneous
boundary conditions of Neumann type on a planar dumbbell domain
which consists of two disjoint domains connected by a thin channel.
We analyse the spectral behaviour of the operator, characterizing the
limit of the eigenvalues and of the eigenprojections as the thickness of
the channel goes to zero. In applications to linear elasticity, the fourth
order operator under consideration is related to the deformation of a
free elastic plate, a part of which shrinks to a segment. In contrast to
what happens with the classical second order case, it turns out that
the limiting equation is here distorted by a strange factor depending
on a parameter which plays the role of the Poisson coefficient of the
represented plate
Nosocomial infection in kidney transplant recipients : a retrospective analysis of a single-center experience
No full textPosttransplant bacterial infections are important because of their influence on patient and graft outcomes. Therefore, prevention of infection as well as prompt diagnosis and appropriate treatment are crucial. In this retrospective analysis, we reviewed all posttransplant bacterial infections occurring during the admission of kidney transplant patients from January 2000 to May 2004. Of our patients, 25% had at least one episode of infection. Patients with immunosuppression based on an mTOR inhibitor showed the highest rate of wound infections compared to those receiving a calcineurin inhibitor (odds ratio 5.6, P < .001). Patients with renal failure caused by a urologic disease revealed a increased risk of a urinary tract infections (odds ratio 5.9, P < .001). Although infection complications are an important cause of morbidity in renal transplantation, the extensive use of antibiotics should be avoided in favor of a strict policy for infection prevention and control. (copyright) 2005 by Elsevier Inc. All rights reserved
Spectral properties of the inhomogeneous Drude-Lorentz model with dissipation
No full textWe establish spectral enclosures and spectral approximation results for the inhomogeneous lossy Drude-Lorentz system with purely imaginary poles, in a possibly unbounded Lipschitz domain of R3. Under
the assumption that the coefficients θe, θm of the material are asymptotically constant at infinity, we
prove that spectral pollution due to domain truncation can lie only in the essential numerical range of a
curl curl0 −f (ω) pencil.
As an application, we consider a conducting metamaterial at the interface with the vacuum; we prove
that the complex eigenvalues with non-trivial real part lie outside the set of spectral pollution. We believe
this is the first result of enclosure of spectral pollution for the Drude-Lorentz model without assumptions of
compactness on the resolvent of the underlying Maxwell operato
Boundary homogenization for a triharmonic intermediate problem
No full textWe consider the triharmonic operator subject to homogeneous boundary conditions of intermediate type on a bounded domain of the N‐dimensional Euclidean space. We study its spectral behaviour when the boundary of the domain undergoes a perturbation of oscillatory type. We identify the appropriate limit problems that depend on whether the strength of the oscillation is above or below a critical threshold. We analyse in detail the critical case that provides a typical homogenization problem leading to a strange boundary term in the limit problem
Hypothermic machine perfusion in kidney transplantation: back to the future?
No full textStatic cold storage is currently the most used method of organ preservation worldwide. However, cutting edge technology and dramatic changes in the donor pattern have lately renewed the interest toward hypothermic machine perfusion. Marginal and cardiac death donors show higher rates of primary non function and delayed graft function compared to standard criteria donors. In this setting, machine perfusion may offer several theoretical advantages such as improved organ preservation, continuous graft evaluation, and ex-vivo conditioning of the graft before implantation. These topics have been recently reassessed by several studies. In particular, perfusion characteristics (renal resistance) and perfusate biomarker concentrations (lactate dehydrogenase, aspartate aminotransferase, heart-type fatty acid binding protein, and IL-18) during machine preservation, proved to be reliable tools to rule out graft viability and predict outcomes after transplantation. Treatment strategies acting on tissue repair, cell metabolism, and allorecognition pathway are also under investigation with promising results. Machine perfusion has finally shown its real potential however, stronger evidences and updated cost-effectiveness analysis are needed to fully support its role for the next future
IMMUNOPHARMACOLOGY OF RAPAMYCIN
No full textRapamycin is the latest in a series of new immunosuppressants. Because
of its unique capacity to inhibit lymphokine signal transduction, the
immune-modulating potentials of rapamycin appear to be different from
the antecedent agents, Cyclosporine and FK506. This influence on the
effector arm of the immune-response makes Rapamycin a suitable candidate
for multiple-drug therapy in combination with Cyclosporine which acts
earlier in the immunoresponse process. Rapamycin, unlike Cyclosporine
and FK506, has been shown to affect B-cell functions and T-cell - B-cell
signal pathways. The effect on antibody synthesis may explain Rapamycin
induced unresponsiveness
JC polyomavirus infections in transplant patients
No full textThe polyomavirus JC virus (JCV) is a small nonenveloped DNA virus that asymptomatically infects about 80% of healthy adults and establishes latency in the kidney tissue. In case of immunodeficient hosts, JCV can lytically infect the oligodendrocytes, causing a fatal demyelinating disease, known as Progressive Multifocal Leukoencephalopathy (PML). Although the reactivation of another human polyomavirus, BK Virus (BKV), is relatively common and its association with the Polyomavirus Associated Nephropathy (PVAN) following renal transplantation is assessed, JCV replication and its impact on graft function and survival is less well studied. In addition, none of the performed studies ruled out the hypothesis that JCV could be associated with certain post-trasplantation clinical syndromes. Thus, monitoring of Polyomaviruses infection, especially during the first 24 months post-transplantation, is recommended
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