268 research outputs found
Virus-induced hepatocellular carcinomas cause antigen-specific local tolerance
T cell surveillance is often effective against virus-associated tumors because of their high immunogenicity. It is not clear why surveillance occasionally fails, particularly against hepatitis B virus- or hepatitis C virus-associated hepatocellular carcinoma (HCC). We established a transgenic murine model of virus-induced HCC by hepatocyte-specific adenovirus-induced activation of the oncogenic SV40 large T antigen (TAg). Adenovirus infection induced cytotoxic T lymphocytes (CTLs) targeted against the virus and TAg, leading to clearance of the infected cells. Despite the presence of functional, antigen-specific T cells, a few virus-infected cells escaped immune clearance and progressed to HCC. These cells expressed TAg at levels similar to HCC isolated from neonatal TAg-tolerant mice, suggesting that CTL clearance does not select for cells with low immunogenicity. Virus-infected mice revealed significantly greater T cell infiltration in early-stage HCC compared with that in late-stage HCC, demonstrating progressive local immune suppression through inefficient T cell infiltration. Programmed cell death protein-1 (PD-1) and its ligand PD-L1 were expressed in all TAg-specific CD8+ T cells and HCC, respectively, which contributed to local tumor-antigen-specific tolerance. Thus, we have developed a model of virus-induced HCC that may allow for a better understanding of human HCC
Near-infrared ps transient photoinduced absorption in conjugated systems
Optical Science, Engineering and Instrumentation '97, 1997, San Diego, CA, United StatesSergey V. Frolov, Werner Gellermann, Z. Valy Vardeny, Masanori Ozaki, Katsumi Yoshino, Thomas J. Barton, and Guglielmo Lanzani "Near-infrared ps transient photoinduced absorption in conjugated systems", Proc. SPIE 3145, Optical Probes of Conjugated Polymers, (1 December 1997). DOI: https://doi.org/10.1117/12.29553
Two-photon absorption spectra of luminescent conducting polymers measured over wide spectral range
Optical Science, Engineering and Instrumentation '97, 1997, San Diego, CA, United StatesRon K. Meyer, Martin Liess, Robert E. Benner, Werner Gellermann, Z. Valy Vardeny, Masanori Ozaki, Katsumi Yoshino, Yi Wei Ding, and Thomas J. Barton "Two-photon absorption spectra of luminescent conducting polymers measured over wide spectral range", Proc. SPIE 3145, Optical Probes of Conjugated Polymers, (1 December 1997). DOI: https://doi.org/10.1117/12.27927
Physical nature of critical wave functions in Fibonacci systems
We report on a new class of critical states in the energy spectrum of general
Fibonacci systems. By introducing a transfer matrix renormalization technique,
we prove that the charge distribution of these states spreads over the whole
system, showing transport properties characteristic of electronic extended
states. Our analytical method is a first step to find out the link between the
spatial structure of these critical wave functions and the quasiperiodic order
of the underlying lattice.Comment: REVTEX 3.0, 11 pages, 2 figures available upon request. To appear in
Phys. Rev. Let
Multi-component optical solitary waves
We discuss several novel types of multi-component (temporal and spatial)
envelope solitary waves that appear in fiber and waveguide nonlinear optics. In
particular, we describe multi-channel solitary waves in bit-parallel-wavelength
fiber transmission systems for high performance computer networks, multi-colour
parametric spatial solitary waves due to cascaded nonlinearities of quadratic
materials, and quasiperiodic envelope solitons due to quasi-phase-matching in
Fibonacci optical superlattices.Comment: 12 pages, 11 figures; To be published in: Proceedings of the Dynamics
Days Asia-Pacific: First International Conference on Nonlinear Science
(Hong-Kong, 13-16 July, 1999), Editor: Bambi Hu (Elsevier Publishers, 2000
Optimization of Single Voxel MR Spectroscopy Sequence Parameters and Data Analysis Methods for Thermometry in Deep Hyperthermia Treatments
Objective:
The difference in the resonance frequency of water and methylene moieties of lipids quantifies in magnetic resonance spectroscopy the absolute temperature using a predefined calibration curve. The purpose of this study was the investigation of peak evaluation methods and the magnetic resonance spectroscopy sequence (point-resolved spectroscopy) parameter optimization that enables thermometry during deep hyperthermia treatments.
Materials and Methods:
Different Lorentz peak-fitting methods and a peak finding method using singular value decomposition of a Hankel matrix were compared. Phantom measurements on organic substances (mayonnaise and pork) were performed inside the hyperthermia 1.5-T magnetic resonance imaging system for the parameter optimization study. Parameter settings such as voxel size, echo time, and flip angle were varied and investigated.
Results:
Usually all peak analyzing methods were applicable. Lorentz peak-fitting method in MATLAB proved to be the most stable regardless of the number of fitted peaks, yet the slowest method. The examinations yielded an optimal parameter combination of 8 cm3 voxel volume, 55 millisecond echo time, and a 90° excitation pulse flip angle.
Conclusion:
The Lorentz peak-fitting method in MATLAB was the most reliable peak analyzing method. Measurements in homogeneous and heterogeneous phantoms resulted in optimized parameters for the magnetic resonance spectroscopy sequence for thermometry
A Fourier (k-) space design approach for controllable photonic band and localization states in aperiodic lattices
In this paper we present a systematic study of photonic bandgap engineering
using aperiodic lattices (ALs). Up to now ALs have tended to be defined by
specific formulae (e.g. Fibonacci, Cantor), and theories have neglected other
useful ALs along with the vast majority of non-useful (random) ALs. Here, we
present a practical and efficient Fourier space-based general theory to
identify all those ALs having useful band properties, which are characterized
by well-defined Fourier (i.e. lattice momentum) components. Direct control of
field localization comes via control of the Parseval strength competition
between the different Fourier components characterizing a lattice. Real-space
optimization of ALs tends to be computationally demanding. However, via our
Fourier space-based simulated annealing inverse optimization algorithm, we
efficiently tailor the relative strength of the AL Fourier components for
precise control of photonic band and localization properties.Comment: 25 pages, 4 figure
Effect of cyclosporin A on proteinuria in the course of glomerulopathy associated with WT1 mutations
Denys–Drash syndrome (DDS) is characterized by progressive glomerulopathy caused by diffuse mesangial sclerosis (DMS), genitourinary defects, and a higher risk of developing Wilms’ tumor. It is commonly assumed that the DMS is unresponsive to any medications. In this report, we present a patient with Denys–Drash syndrome, in whom the cyclosporine A (CsA) was found to induce total remission. This observation and observations of other authors confirm that in genetic forms of nephrotic syndrome, the proteinuric effect of CsA may be due to a non-immunologic mechanism. We confirm the beneficial effect of CsA treatment in DDS; however, the potential nephrotoxicity of this drug will probably not allow long-term use
Cyclosporine-A-induced nephrotoxicity in children with minimal-change nephrotic syndrome: long-term treatment up to 10Â years
The impact of cyclosporine A (CsA) therapy in patients with steroid-dependent nephrotic-syndrome (SDNS) on long-term renal function is controversial. Data beyond 5 years are rare. Long-term renal function was evaluated in children with SDNS with and without CsA therapy, especially beyond 5 years. Twenty children were treated with CsA (study group) for a mean of 5.4 ± 2.2 years (ten patients for 5–11 years). Glomerular filtration rate (GFR) was calculated before and after 3 and 12 months and at latest follow-up of therapy. Fifteen children with cyclophosphamide-treated SDNS without CsA served as controls. In the study group, GFR decreased within 12 months from 136 ± 19 to 120 ± 31, to 114 ± 14 ml/min per 1.73 m2 at latest follow-up (p < 0.0001). Patients with CsA > 5 years had a GFR of 111 ± 14 ml/min per 1.73 m2 at latest follow-up without a GFR below 90 ml/min per 1.73 m2. No CsA toxicity was found in biopsies. In the control group, GFR dropped within 3 months, from 137 ± 27 to 130 ± 24, to 126 ± 19 ml/min per 1.73 m2 at latest follow-up (p = 0.1). Patients with and without nephrotoxic CsA therapy showed a drop in GFR. In CsA-treated patients, GFR was about 12% lower at latest follow-up compared with patients without nephrotoxic therapy but always remained within normal range. CsA seems to be safe, even in long-term treatment for more than 5 years
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