Enzymatic antioxidant defense in isolated rat hepatocytes exposed to cadmium

The aim of the study was the evaluation of cadmium effects on the activity of antioxidant enzymes in rat hepatocytes. The studies were conducted with isolated rat hepatocytes incubated for 1 or 2 hours in a modified (deprived of carbonates with phosphates) Williams’ E medium (MWE) in the presence of cadmium chloride (25, 50 and 200 μM). Hepatocytes incubated in the MWE medium without cadmium chloride were used as a control. The application of the modified Williams’ E medium allowed for the appearance of cadmium compounds in a soluble form that is indispensable for suitable estimation of its toxic action. There were evaluated markers of the oxidative stress such as: concentration of thiobarbiturate reactive substances (TBARS) – proportional to the level of lipid peroxidation, concentration of reduced glutathione (GSH), and the activity of antioxidant enzymes, including superoxide dismutase (SOD1 and SOD2), catalase (CAT), total glutathione peroxidase (GSHPx), selenium – dependent glutathione peroxidase (SeGSHPx), glutathione transferase (GST) and glutathione reductase (GSHR). Alterations of antioxidant enzymes activity, the level of TBARS and GSH in isolated rat hepatocytes caused by cadmium in vitro, were shown to depend on the concentration and time of exposure of cells to this metal. The increased level of TBARS and GSH was observed as well as changes in the activity of antioxidant enzymes. The activity of SOD isoenzymes and CAT was increased, whereas GSHPx and GST were decreased. These results indicate that cadmium induces oxidative stress followed by alterations in the cellular antioxidant enzyme system in isolated rat hepatocytes

The antioxidant defence mechanisms of parasite and host after chronic Hymenolepis diminuta infestation of the rat

The aim of the present study was to determine antioxidant defence mechanisms in the rat and Hymenolepis diminuta after long-term infestation. We determined levels of oxidative stress markers, and activity of antioxidant enzymes in the rat small intestine and in particular parts of H. diminuta. Observed changes in antioxidant enzymes activity in H. diminuta and the rat intestine indicate the defence against parasitic infestation and probably allowed parasite to adapt and live in oxidative stress

Comparison of the MChip to Viral Culture, Reverse Transcription-PCR, and the QuickVue Influenza A+B Test for Rapid Diagnosis of Influenza

The performance of a diagnostic microarray (the MChip assay) for influenza was compared in a blind study to that of viral culture, reverse transcription (RT)-PCR, and the QuickVue Influenza A+B test. The patient sample data set was composed of 102 respiratory secretion specimens collected between 29 December 2005 and 2 February 2006 at Scott & White Hospital and Clinic in Temple, Texas. Samples were collected from a wide range of age groups by using direct collection, nasal/nasopharyngeal swabs, or nasopharyngeal aspiration. Viral culture and the QuickVue assay were performed at the Texas site at the time of collection. Aliquots for each sample, identified only by study numbers, were provided to the University of Colorado and Vanderbilt University teams for blinded analysis. When referenced to viral culture, the MChip exhibited a clinical sensitivity of 98% and a clinical specificity of 98%. When referenced to RT-PCR, the MChip assay exhibited a clinical sensitivity of 92% and a clinical specificity of 98%. While the MChip assay currently requires 7 to 8 h to complete the analysis, a significant advantage of the test for influenza virus-positive samples is simultaneous detection and full subtype identification for the two subtypes currently circulating in humans (A/H3N2 and A/H1N1) and avian (A/H5N1) viruses

Influenza-induced immune suppression to methicillin-resistant Staphylococcus aureus is mediated by TLR9.

Bacterial lung infections, particularly with methicillin-resistant Staphylococcus aureus (MRSA), increase mortality following influenza infection, but the mechanisms remain unclear. Here we show that expression of TLR9, a microbial DNA sensor, is increased in murine lung macrophages, dendritic cells, CD8+ T cells and epithelial cells post-influenza infection. TLR9-/- mice did not show differences in handling influenza nor MRSA infection alone. However, TLR9-/- mice have improved survival and bacterial clearance in the lung post-influenza and MRSA dual infection, with no difference in viral load during dual infection. We demonstrate that TLR9 is upregulated on macrophages even when they are not themselves infected, suggesting that TLR9 upregulation is related to soluble mediators. We rule out a role for elevations in interferon-γ (IFNγ) in mediating the beneficial MRSA clearance in TLR9-/- mice. While macrophages from WT and TLR9-/- mice show similar phagocytosis and bacterial killing to MRSA alone, following influenza infection, there is a marked upregulation of scavenger receptor A and MRSA phagocytosis as well as inducible nitric oxide synthase (Inos) and improved bacterial killing that is specific to TLR9-deficient cells. Bone marrow transplant chimera experiments and in vitro experiments using TLR9 antagonists suggest TLR9 expression on non-hematopoietic cells, rather than the macrophages themselves, is important for regulating myeloid cell function. Interestingly, improved bacterial clearance post-dual infection was restricted to MRSA, as there was no difference in the clearance of Streptococcus pneumoniae. Taken together these data show a surprising inhibitory role for TLR9 signaling in mediating clearance of MRSA that manifests following influenza infection

Integrin αvβ1 promotes infection by human metapneumovirus

Human metapneumovirus (hMPV) is a recently described paramyxovirus that causes lower respiratory infections in children and adults worldwide. The hMPV fusion (F) protein is a membrane-anchored glycoprotein and major protective antigen. All hMPV F protein sequences determined to date contain an Arg-Gly-Asp (RGD) sequence, suggesting that F engages RGD-binding integrins to mediate cell entry. The divalent cation chelator EDTA, which disrupts heterodimeric integrin interactions, inhibits infectivity of hMPV but not the closely related respiratory syncytial virus (RSV), which lacks an RGD motif. Function-blocking antibodies specific for αvβ1 integrin inhibit infectivity of hMPV but not RSV. Transfection of nonpermissive cells with αv or β1 cDNAs confers hMPV infectivity, whereas reduction of αv and β1 integrin expression by siRNA inhibits hMPV infection. Recombinant hMPV F protein binds to cells, whereas Arg-Gly-Glu (RGE)-mutant F protein does not. These data suggest that αvβ1 integrin is a functional receptor for hMPV