Chemotactic and Inflammatory Responses in the Liver and Brain Are Associated with Pathogenesis of Rift Valley Fever Virus Infection in the Mouse

Rift Valley fever virus (RVFV) is a major human and animal pathogen associated with severe disease including hemorrhagic fever or encephalitis. RVFV is endemic to parts of Africa and the Arabian Peninsula, but there is significant concern regarding its introduction into non-endemic regions and the potentially devastating effect to livestock populations with concurrent infections of humans. To date, there is little detailed data directly comparing the host response to infection with wild-type or vaccine strains of RVFV and correlation with viral pathogenesis. Here we characterized clinical and systemic immune responses to infection with wild-type strain ZH501 or IND vaccine strain MP-12 in the C57BL/6 mouse. Animals infected with live-attenuated MP-12 survived productive viral infection with little evidence of clinical disease and minimal cytokine response in evaluated tissues. In contrast, ZH501 infection was lethal, caused depletion of lymphocytes and platelets and elicited a strong, systemic cytokine response which correlated with high virus titers and significant tissue pathology. Lymphopenia and platelet depletion were indicators of disease onset with indications of lymphocyte recovery correlating with increases in G-CSF production. RVFV is hepatotropic and in these studies significant clinical and histological data supported these findings; however, significant evidence of a pro-inflammatory response in the liver was not apparent. Rather, viral infection resulted in a chemokine response indicating infiltration of immunoreactive cells, such as neutrophils, which was supported by histological data. In brains of ZH501 infected mice, a significant chemokine and pro-inflammatory cytokine response was evident, but with little pathology indicating meningoencephalitis. These data suggest that RVFV pathogenesis in mice is associated with a loss of liver function due to liver necrosis and hepatitis yet the long-term course of disease for those that might survive the initial hepatitis is neurologic in nature which is supported by observations of human disease and the BALB/c mouse model

Functionalization of biomaterials for joint implant application

1 - Articl

Influence of surface mechanical attrition treatment (SMAT) on oxidation behavior of 316L stainless steel at 650°C

Abstract In this paper, the effects of Surface Mechanical Attrition Treatment on the high-temperature oxidation of AISI 316L austenitic stainless steel are investigated. Samples treated with different conditions were oxidized at 650 o C in order to study the effect of this type of nanocrystallisation on the oxidation resistance of the alloy concerned. X-ray diffraction and in-situ Raman spectroscopy were used to identify the oxides formed at the surface. The results indicate the presence of hematite and chromium oxides. Experimental results obtained by Raman spectroscopy were also used to study the stress evolution in Cr2O3 films during isothermal conditions

Ion implantation reinforcement of the protective efficiency of nickel in artificial sea-water

Ni bulk specimens have been implanted with Cr, Cu and Ar ions (4 × 1016 ions/cm2, 60 keV) in order to distinguish between chemical and radiation damage effects on protection corrosion. The corrosion behaviour in artificial sea-water of ion-implanted and pure Ni has been studied at room temperature by electrochemical impedance spectroscopy (EIS) technique. EIS spectra of ion-implanted Ni exhibit one capacitance loop while in pure Ni two distinct loops are observed. Moreover an important increase in the polarisation resistance is noticed for all implanted ions. Theses changes in EIS behaviour with implantation is related to the increase of the superficial layer density resulting in a decrease of heterogeneity of the passive layer. Equivalent circuits are proposed to fit the impedance spectra and corresponding electrochemical parameters are deduced. © 2002 Elsevier Science B.V. All rights reserved

The influence of isocyanurate content on the bioperformance of hydrocarbon-based polyurethanes

International audienc

Influence of a chromium ion implantation on the passive behaviour of nickel in artificial sea-water: An EIS and XPS study

The passive behaviour in artificial sea-water of Cr-implanted (4 × 1016 ions/cm2, 60 keV) and non-implanted Ni was studied at room temperature by electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The transfer resistance obtained for the implanted specimen (Rt ∼ 5586 kΩ cm2) is extremely enhanced compared to the corresponding value of the non-implanted Ni (Rt ∼ 94 kΩ cm2) indicating a considerable increase in the protective efficiency of the implanted layer. The EIS spectra of ion-implanted Ni exhibit one capacitance loop while in the non-implanted Ni two distinct loops can be observed. These changes in EIS behaviour by the ion-implantation are related to the increase of the superficial layer density resulting in a more stable passive layer. Equivalent circuits were proposed to fit the impedance spectra and corresponding electrochemical parameters deduced. These findings were compared with the results obtained by analysis of the passive film formed on Ni, performed by XPS, and with previous investigations of similar alloys. It appears that the passive film formed on Ni consists of NiO and Ni(OH)2 whereas the chromium implantation leads to the formation in the passive state of Cr oxides and hydroxides which are responsible of the large increase of the transfer resistance. © 2001 Elsevier Science B.V