430 research outputs found
Effects of neo-adjuvant chemotherapy for oesophago-gastric cancer on neuro-muscular gastric function
Delayed gastric emptying symptoms are often reported after chemotherapy. This study aims to characterise the effects of chemotherapy on gastric neuro-muscular function. Patients undergoing elective surgery for oesophago-gastric cancer were recruited. Acetylcholinesterase, nNOS, ghrelin receptor and motilin expressions were studied in gastric sections from patients receiving no chemotherapy (n = 3) or oesophageal (n = 2) or gastric (n = 2) chemotherapy. A scoring system quantified staining intensity (0–3; no staining to strong). Stomach sections were separately suspended in tissue baths for electrical field stimulation (EFS) and exposure to erythromycin or carbachol; three patients had no chemotherapy; four completed cisplatin-based chemotherapy within 6 weeks prior to surgery. AChE expression was markedly decreased after chemotherapy (scores 2.3 ± 0.7, 0.5 ± 0.2 and 0 ± 0 in non-chemotherapy, oesophageal- and gastric-chemotherapy groups (p < 0.03 each) respectively. Ghrelin receptor and motilin expression tended to increase (ghrelin: 0.7 ± 0.4 vs 2.0 ± 0.4 and 1.2 ± 0.2 respectively; p = 0.04 and p = 0.2; motilin: 0.7 ± 0.5 vs 2.2 ± 0.5 and 2.0 ± 0.7; p = 0.06 and p = 0.16). Maximal contraction to carbachol was 3.7 ± 0.7 g and 1.9 ± 0.8 g (longitudinal muscle) and 3.4 ± 0.4 g and 1.6 ± 0.6 (circular) in non-chemotherapy and chemotherapy tissues respectively (p < 0.05 each). There were loss of AChE and reduction in contractility to carbachol. The tendency for ghrelin receptors to increase suggests an attempt to upregulate compensating systems. Our study offers a mechanism by which chemotherapy markedly alters neuro-muscular gastric function
Weak Localization Effect in Superconductors by Radiation Damage
Large reductions of the superconducting transition temperature and
the accompanying loss of the thermal electrical resistivity (electron-phonon
interaction) due to radiation damage have been observed for several A15
compounds, Chevrel phase and Ternary superconductors, and in
the high fluence regime. We examine these behaviors based on the recent theory
of weak localization effect in superconductors. We find a good fitting to the
experimental data. In particular, weak localization correction to the
phonon-mediated interaction is derived from the density correlation function.
It is shown that weak localization has a strong influence on both the
phonon-mediated interaction and the electron-phonon interaction, which leads to
the universal correlation of and resistance ratio.Comment: 16 pages plus 3 figures, revtex, 76 references, For more information,
Plesse see http://www.fen.bilkent.edu.tr/~yjki
An Alphavirus-Based Adjuvant Enhances Serum and Mucosal Antibodies, T Cells, and Protective Immunity to Influenza Virus in Neonatal Mice
Neonatal immune responses to infection and vaccination are biased toward TH2 at the cost of proinflammatory TH1 responses needed to combat intracellular pathogens. However, upon appropriate stimulation, the neonatal immune system can induce adult-like TH1 responses. Here we report that a new class of vaccine adjuvant is especially well suited to enhance early life immunity. The GVI3000 adjuvant is a safe, nonpropagating, truncated derivative of Venezuelan equine encephalitis virus that targets dendritic cells (DCs) in the draining lymph node (DLN) and produces intracellular viral RNA without propagating to other cells. RNA synthesis strongly activates the innate immune response so that in adult animals, codelivery of soluble protein antigens induces robust humoral, cellular, and mucosal responses. The adjuvant properties of GVI3000 were tested in a neonatal BALB/c mouse model using inactivated influenza virus (iFlu). After a single immunization, mice immunized with iFlu with the GVI3000 adjuvant (GVI3000-adjuvanted iFlu) had significantly higher and sustained influenza virus-specific IgG antibodies, mainly IgG2a (TH1), compared to the mice immunized with antigen only. GVI3000 significantly increased antigen-specific CD4+ and CD8+ T cells, primed mucosal immune responses, and enhanced protection from lethal challenge. As seen in adult mice, the GVI3000 adjuvant increased the DC population in the DLNs, caused activation and maturation of DCs, and induced proinflammatory cytokines and chemokines in the DLNs soon after immunization, including gamma interferon (IFN-γ), tumor necrosis factor alpha (TNF-α), granulocyte colony-stimulating factor (G-CSF), and interleukin 6 (IL-6). In summary, the GVI3000 adjuvant induced an adult-like adjuvant effect with an influenza vaccine and has the potential to improve the immunogenicity and protective efficacy of new and existing neonatal vaccines
Bayesian hierarchical clustering for studying cancer gene expression data with unknown statistics
Clustering analysis is an important tool in studying gene expression data. The Bayesian hierarchical clustering (BHC) algorithm can automatically infer the number of clusters and uses Bayesian model selection to improve clustering quality. In this paper, we present an extension of the BHC algorithm. Our Gaussian BHC (GBHC) algorithm represents data as a mixture of Gaussian distributions. It uses normal-gamma distribution as a conjugate prior on the mean and precision of each of the Gaussian components. We tested GBHC over 11 cancer and 3 synthetic datasets. The results on cancer datasets show that in sample clustering, GBHC on average produces a clustering partition that is more concordant with the ground truth than those obtained from other commonly used algorithms. Furthermore, GBHC frequently infers the number of clusters that is often close to the ground truth. In gene clustering, GBHC also produces a clustering partition that is more biologically plausible than several other state-of-the-art methods. This suggests GBHC as an alternative tool for studying gene expression data. The implementation of GBHC is available at https://sites.
google.com/site/gaussianbhc
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Overview of the results of the organics PET Study of the cometary samples returned from comet Wild 2 by the Stardust mission
This presenation will provide an overview of the efforts and results produced by the Organics Preliminary Examination Team during their studies of the samples returned from comet Wild 2 by the Stardust spacecraft
Degradation and healing in a generalized neo-Hookean solid due to infusion of a fluid
The mechanical response and load bearing capacity of high performance polymer
composites changes due to diffusion of a fluid, temperature, oxidation or the
extent of the deformation. Hence, there is a need to study the response of
bodies under such degradation mechanisms. In this paper, we study the effect of
degradation and healing due to the diffusion of a fluid on the response of a
solid which prior to the diffusion can be described by the generalized
neo-Hookean model. We show that a generalized neo-Hookean solid - which behaves
like an elastic body (i.e., it does not produce entropy) within a purely
mechanical context - creeps and stress relaxes when infused with a fluid and
behaves like a body whose material properties are time dependent. We
specifically investigate the torsion of a generalized neo-Hookean circular
cylindrical annulus infused with a fluid. The equations of equilibrium for a
generalized neo-Hookean solid are solved together with the convection-diffusion
equation for the fluid concentration. Different boundary conditions for the
fluid concentration are also considered. We also solve the problem for the case
when the diffusivity of the fluid depends on the deformation of the generalized
neo-Hookean solid.Comment: 24 pages, 10 figures, submitted to Mechanics of Time-dependent
Material
Performance Assessment for Geological Disposal of Graphite Waste Containing TRISO Particles
This paper presents a deterministic performance assessment for spent fuel from deep-burn modular hightemperature reactors (DBMHRs) in the proposed Yucca Mountain repository. Typical DBMHR designs utilize fuel elements manufactured from graphite. The fuel itself is made of TRISO particles containing the fissile material. The performance of the DBMHR spent fuel (DBSF) was evaluated in terms of the annual dose to the reasonably maximally exposed individual (RMEI) under various hydrogeological conditions. Part of this evaluation was an analysis of the graphite waste matrix and of the TRISO particles under repository conditions, the result of which indicates that the lifetime of the graphite matrix greatly exceeds that of the TRISO particles and that it is the graphite, not the TRISO particles, that serves to sequester the radionuclides within the fuel matrix. Under all 14 cases considered, DBSF is seen to comply with the annual dose standards set in Part 197 of Title 40 of the Code of Federal Regulations, for exposure via groundwater contamination under current climatic conditions. Parametric studies for the effect of waste matrix lifetime on annual dose received by the RMEI indicate that repository performance is sensitively linked to waste matrix durability because most radionuclides including actinides are likely to be released congruently with the graphite matrix
Clinical profile and treatment of infantile spasms using vigabatrin and ACTH - a developing country perspective
Background: Infantile spasms represent a serious epileptic syndrome that occurs in the early infantile age. ACTH and Vigabatrin are actively investigated drugs in its treatment. This study describes the comparison of their efficacy in a large series of Patients with infantile spasms from Pakistan. Methods: All Patients with infantile spasms who presented to Aga Khan University Hospital, Karachi, Pakistan from January, 2006 to April, 2008 were included in this study. Inclusion criteria were clinical symptoms of infantile spasms, hypsarrythmia or modified hyparrythmia on electroencephalography, at least six months of follow-up period and receipt of any of the two drugs mentioned above. The type of drug distribution was random according to the availability, cost and ease of administration. Results: Fifty six cases fulfilled the inclusion criteria. 62.5% were males. Mean age at onset of seizures was 5 +/- 1.4 months. Fifty two (92.8%) Patients demonstrated hypsarrythmia on electroencephalography. 64.3% cases were identified as symptomatic while 19.6% were cryptogenic and 16.1% were idiopathic. Eighteen Patients received ACTH while 38 Patients received Vigabatrin as first line therapy. Initial response to first line therapy was similar (50% for ACTH and 55.3% for Vigabatrin). Overall, the symptomatic and idiopathic groups responded better to Vigabatrin. The relapse rate was higher for ACTH as compared to Vigabatrin (55.5% vs. 33.3%) when considering the first line therapy. Four Patients evolved to Lennox-Gastaut variant, all of these Patients had initially received Vigabatrin and then ACTH. Conclusion: Vigabatrin and ACTH showed no significant difference in the initial treatment of infantile spasms. However, Patients receiving ACTH were 1.2 times more likely to relapse as compared to the Patients receiving Vigabatrin when considering monotherapy. We suggest that Vigabatrin should be the initial drug of choice in Patients presenting with infantile spasms. However, larger studies from developing countries are required to validate the therapeutic trends observed in this study
Density of Common Complex Ocular Traits in the Aging Eye: Analysis of Secondary Traits in Genome-Wide Association Studies
Genetic association studies are identifying genetic risks for common complex ocular traits such as age-related macular degeneration (AMD). The subjects used for discovery of these loci have been largely from clinic-based, case-control studies. Typically, only the primary phenotype (e.g., AMD) being studied is systematically documented and other complex traits (e.g., affecting the eye) are largely ignored. The purpose of this study was to characterize these other or secondary complex ocular traits present in the cases and controls of clinic-based studies being used for genetic study of AMD. The records of 100 consecutive new patients (of any diagnosis) age 60 or older for which all traits affecting the eye had been recorded systematically were reviewed. The average patient had 3.5 distinct diagnoses. A subset of 10 complex traits was selected for further study because they were common and could be reliably diagnosed. The density of these 10 complex ocular traits increased by 0.017 log-traits/year (P = 0.03), ranging from a predicted 2.74 at age 60 to 4.45 at age 90. Trait-trait association was observed only between AMD and primary vitreomacular traction (P = 0.0009). Only 1% of subjects age 60 or older had no common complex traits affecting the eye. Extrapolations suggested that a study of 2000 similar subjects would have sufficient power to detect genetic association with an odds ratio of 2.0 or less for 4 of these 10 traits. In conclusion, the high prevalence of complex traits affecting the aging eye and the inherent biases in referral patterns leads to the potential for confounding by undocumented secondary traits within case-control studies. In addition to the primary trait, other common ocular phenotypes should be systematically documented in genetic association studies so that adjustments for potential trait-trait associations and other bias can be made and genetic risk variants identified in secondary analyses
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