361 research outputs found

    Conserved visual capacity of rats under red light

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    Recent studies examine the behavioral capacities of rats and mice with and without visual input, and the neuronal mechanisms underlying such capacities. These animals are assumed to be functionally blind under red light, an assumption that might originate in the fact that they are dichromats who possess ultraviolet and green but not red cones. But the inability to see red as a color does not necessarily rule out form vision based on red light absorption. We measured Long-Evans rats’ capacity for visual form discrimination under red light of various wavelength bands. Upon viewing a black and white grating, they had to distinguish between two categories of orientation, horizontal and vertical. Psychometric curves plotting judged orientation versus angle demonstrate the conserved visual capacity of rats under red light. Investigations aiming to explore rodent physiological and behavioral functions in the absence of visual input should not assume red-light blindness

    Vaccination of rainbow trout against Streptococcus iniae infection: comparison of different routes of administration and different vaccines

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    Antibody production and clinical efficacy (relative percent survival RPS) were measured in 40±5g rainbow trout after immunization with two types of Streptococcus iniae vaccines consisting of formalin killed cells (FKC) and FKC enriched with the bacterial extracellular products (ECP) administered by intraperitoneal (i.p), immersion and oral routes at 16±1°C for 18 weeks. No significant difference was found in antibody levels among the fish i.p immunized with FKC enriched with ECP plus Freunds' adjuvant (FA), FKC plus FA and FKC vaccines (P>0.05), whilst the antibody production was significantly higher in these three groups than fish immunized by immersion and oral routes of FKC and FKC enriched ECP (P0.05). The RPSs ranging 82.6-100, 73.9-95 and 73.9-91.7% were obtained in the fish intraperitoneally immunized with FKC enriched ECP plus FA, FKC plus FA and FKC vaccines, respectively, compared to 0% survival for the control fish. Also, RPS in fish vaccinated by the immersion route was in the range 45.8-30.4% after 18 weeks post-vaccination. Efficacy of oral vaccination of fish with FKC plus ECP was in range of 8.7-29% and that of fish orally vaccinated with FKC resulted in 8.7-20.8% protection

    Pelargonidin improves passive avoidance task performance in a rat amyloid beta25-35 model of Alzheimer�s disease via estrogen receptor independent pathways

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    Alzheimer�s disease (AD) is a disorder with multiple pathophysiological causes, destructive outcomes, and no available definitive cure. Pelargonidin (Pel), an anthocyanin derivative, is an estrogen receptor agonist with little estrogen side effects. This study was designed to assess Pel memory enhancing effects on the a rat Amyloid Beta25-35 (Aβ) intrahippocampal microinjections model of AD in the passive avoidance task performance paradigm and further evaluate the potential estrogen receptor role on the memory- evoking compound. Equally divided rats were assigned to 5 groups of sham, Aβ intrahippocampal microinjected, Pel pretreated (10 mg/kg; P.O), α estrogen antagonist intra-cerebrovascular (i.c.v.) microinjected, and β estrogen antagonist (i.c.v) microinjected animals. Intrahippocampal microinjections of Aβ were adopted to provoke AD model. Passive avoidance task test was also used to assess memory performance. Pel pretreatment prior to Aβ microinjections significantly improved step-through latency (P<0.001) in passive avoidance test. In α and β estrogen, antagonists received animals, passive avoidance task performance was not statistically changed (P=0.11 & P=0.41 respectively) compared to Pel pretreated and sham animals. Our results depicted that Pel improves Aβ induced memory dysfunction in passive avoidance test performance through estrogen receptor independently related pathways. © 2016 Tehran University of Medical Sciences. All rights reserved

    Extreme Peripheral Blood Plasmacytosis Mimicking Plasma Cell Leukemia as a Presenting Feature of Angioimmunoblastic T-Cell Lymphoma (AITL).

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    Angioimmunoblastic T-cell lymphoma (AITL) is one of four major subtypes of nodal peripheral T cell lymphoma, characterized by its cell of origin, the follicular helper T-cell (TFH). Patients typically present with prominent constitutional (B) symptoms, generalized lymphadenopathy, hepatosplenomegaly, cytopenias, and rash. Here we present a case of a 62-year-old male with progressive cervical adenopathy, fevers and weight loss presenting with extreme polyclonal plasmacytosis and high plasma EBV viral load. While the initial presentation appeared to mimic plasma cell leukemia or severe infection, lymph node biopsy and bone marrow biopsy confirmed a diagnosis of AITL. This case highlights the heterogeneity of the clinical presentation of AITL to enable physicians to more promptly recognize, diagnose and initiate treatment

    Local field enhancement of nano-structured metallic target irradiated by polarized laser beam

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    The local field enhancement is studied numerically in samples of metallic nanoparticles (NPs) randomly distributed over a metallic substrate. The sample was assumed to be irradiated by polarized laser beam. Based on dipole-dipole approximation (DDA), the electric field was calculated Two-dimensionally at the irradiated region. The results show that the optimized field enhancement is strongly depends on NPs characteristics, beam polarization and incident angle

    Development of constitutive model for precast prestressed concrete segmental columns

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    The interest of using precast segmental columns in construction of concrete bridges has significantly increased in recent years. One research area of concrete bridges is the application of Precast Prestressed Concrete Segmental (PPCS) Column in any structural analysis software or FE program code. Modeling a PPCS column, which consists of various materials with interaction between them, is complicated and time-consuming. This research attempts to formulate the stiffness matrix of PPCS columns in order to form the constitutive model in linear form to evaluate the response of the columns. A two-dimensional finite element model is presented in the finite element package ANSYS. Parametric studies are conducted by finite element models to verify the constitutive models for the PPCS column with a different number of concrete segments. Comparison between the constitutive model and the FE program results indicates that the constitutive model is accurate enough to predict the deformation of the PPCS columns

    Polymorphisms of MTHFR and MTR genes are not related to susceptibility to childhood ALL in north India

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    Background:Acute lymphoblastic leukemia (ALL) is the most worldwide common type of childhood cancer. Methylenetetrahydrofolate reductase (MTHFR) and 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR) participate in folate pathways and are known as critical factors for DNA integrity as well as DNA hypomethylation. The aim of this work is to investigate frequency of MTHFR (677C→T and 1298A→C) and MTR (2756A→G) polymorphisms and their interaction with respect to possible effect on risk of childhood ALL among North Indian population. Procedure: A case control study from has been conducted on bone marrow and peripheral blood samples from 125 ALL patients and 100 sex-age matched healthy controls using PCR-RFLP method. Results: No statistically significant differences were observed for different genotypes between patients and controls (p>0.05). Significant difference for the risk of ALL in individuals having genotype of MTHFR 677TT (OR=0.61, 95% CI=0.21–1.77) and MTHFR 1298CC (OR=0.56, 95% CI=0.18–1.68) was not observed. The correlation of SNP of MTR gene and risk of ALL was not observed, too. Conclusions: The differences in distribution of possible combined genotypes of MTHFR (677C→T, 1298A→C) and MTR (2756A→G) between ALL patients and controls were statistically insignificant
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