169 research outputs found
Leverage, Balance Sheet Size and Wholesale Funding
Some evidence points to the procyclicality of leverage among financial institutions leading to aggregate volatility. This procyclicality occurs when financial institutions finance their assets with non-equity funding (i.e., debt financed asset expansions). Wholesale funding is an important source of market-based funding that allows some institutions to quickly adjust their leverage. As such, financial institutions that rely on wholesale funding are expected to have higher degrees of leverage procyclicality. Using high frequency balance sheet data for the universe of banks, this study tries to identify (i) if such a positive link exists between the assets and leverage in Canada, (ii) how wholesale funding plays a role for this link, and (iii) market and macroeconomic factors associated with this link. The findings of the empirical analysis suggest that a strong positive link exists between asset growth and leverage growth, and the use to wholesale funding is an important determinant of this relationship. Furthermore, liquidity of several short-term funding markets matters for procyclicality of leverage.Financial stability; Financial system regulation and policies; Recent economic and financial developments
Role of glycosaminoglycans of biglycan in BMP-2 signaling
Recently we have reported that biglycan (BGN) promotes osteoblast differentiation and that this function is due in part to its ability to positively modulate bone morphogenetic protein (BMP) functions. In this study we investigated the role of glycosaminoglycans (GAGs) of BGN in this function using in vitro and in vivo models. C2C12 myogenic cells were treated or untreated with BMP-2 alone or in combination with glycanated, partially glycanated or de-glycanated BGN, and the effects on BMP signaling and function were assessed by Smad1/5/8 phosphorylation and alkaline phosphatase (ALP) activity. Furthermore, the effect of de-glycanation of BGN on BMP-2 induced osteogenesis was investigated employing a rat mandible defect model. The defects were filled with collagen scaffolds loaded with glycanated, partially glycanated or de-glycanated BGN alone or in combination with a sub-optimal dose of BMP-2 (subBMP). In in vitro experiments, BMP signaling and function were the greatest when BMP-2 was combined with de-glycanated BGN among the groups tested. In the rat mandible experiments, μCT analyses revealed that the newly formed bone was significantly increased only when subBMP was combined with de-glycanated BGN. The data indicate that the GAG component of BGN functions as a suppressor for the BGN-assisted BMP function
Recombinant Biglycan Promotes Bone Morphogenetic Protein-induced Osteogenesis
The aim of this study was to determine the effects of glutathione-S-transferase-fused recombinant biglycan (GST-BGN) on craniofacial bone regeneration. We recently demonstrated a positive effect of tissue-derived BGN on bone morphogenetic protein 2 (BMP-2) function, which is exerted likely via the BGN core protein. Here, we investigated the effects of GST-BGN lacking any posttranslational modifications on BMP-2 function in vitro and in vivo. In the C2C12 cell culture system, BMP-2-induced Smad 1/5/8 phosphorylation and alkaline phosphatase activity were both enhanced by the addition of GST-BGN. For the in vivo effect, we employed a Sprague-Dawley rat mandible defect model utilizing 1 µg (optimal) or 0.1 µg (suboptimal) of BMP-2 combined with 0, 2, 4, or 8 µg of GST-BGN. At 2 weeks post-surgery, newly formed bone was evaluated by microcomputed tomography and histologic analyses. The results revealed that the greatest amounts of bone within the defect were formed in the groups of suboptimal BMP-2 combined with 4 or 8 µg of GST-BGN. Also, bone was well organized versus that formed by the optimal dose of BMP. These results indicate that recombinant BGN is an efficient substrate to promote low-dose BMP-induced osteogenesis
Effect of fenofibrate on microcirculation and wound healing in healthy and diabetic mice
<p>Abstract</p> <p>Objective</p> <p>Disturbances in wound healing in patients with hyperglycaemic blood sugar values are a common clinical problem. Recent studies identified PPARα-ligands as potential skin therapeutic agents. The aim of this study was to investigate the effects of oral fenofibrate treatment on dermal wound healing and micro-circulatory parameters in diabetic mice.</p> <p>Methods</p> <p>Dermal wounds were created in CD-1 mice. Mice were randomized into four treatment groups: diabetic mice treated (dbf) or not-treated with fenofibrate (dbnf). As controls served non-diabetic mice treated (ndf) or not-treated with fenofibrate (ndnf). At various points in time microcirculation was analyzed by intravital fluorescent microscopy to determine wound surface area, vessel diameter, plasma leakage, functional capillary density, and leukocyte/endothelium interaction.</p> <p>Results</p> <p>The dbf-mice showed a significantly increased diameter of the venules and the arterioles up to 3 days after wound creation compared to dbnf-mice. However, wound healing was not improved in dbf-compared to dbnf-mice. Surprisingly, all microcirculatory parameter (vessel diameter, plasma leakage and functional capillary density) were not deteriorated in dbnf-compared to ndnf-mice.</p> <p>Conclusion</p> <p>We confirm that high blood sugar values lead to a delayed wound healing, but this could not traced back to altered microcirculatory patterns. Furthermore, in dbf-mice an improved vasodilatatory function of small vessels could be detected, but with no substantial effect on wound healing. Further studies are needed to clarify, if topical application of fenofibrate might be beneficial.</p
Loss of BMP signaling through BMPR1A in osteoblasts leads to greater collagen cross-link maturation and material-level mechanical properties in mouse femoral trabecular compartments
Bone morphogenetic protein (BMP) signaling pathways play critical roles in skeletal development and new bone formation. Our previous study, however, showed a negative impact of BMP signaling on bone mass because of the osteoblast-specific loss of a BMP receptor (i.e. BMPR1A) showing increased trabecular bone volume and mineral density in mice. Here, we investigated the bone quality and biomechanical properties of the higher bone mass associated with BMPR1A deficiency using the osteoblast-specific Bmpr1a conditional knockout (cKO) mouse model. Collagen biochemical analysis revealed greater levels of the mature cross-link pyridinoline in the cKO bones, in parallel with upregulation of collagen modifying enzymes. Raman spectroscopy distinguished increases in the mature to immature cross-link ratio and mineral to matrix ratio in the trabecular compartments of cKO femora, but not in the cortical compartments. The mineral crystallinity was unchanged in the cKO in either the trabecular or cortical compartments. Further, we tested the intrinsic material properties by nanoindentation and found significantly higher hardness and elastic modulus in the cKO trabecular compartments, but not in the cortical compartments. Four point bending tests of cortical compartments showed lower structural biomechanical properties (i.e. strength and stiffness) in the cKO bones due to the smaller cortical areas. However, there were no significant differences in biomechanical performance at the material level, which was consistent with the nanoindentation test results on the cortical compartment. These studies emphasize the pivotal role of BMPR1A in the determination of bone quality and mechanical integrity under physiological conditions, with different impact on femoral cortical and trabecular compartments
Dendritic and T Cell Response to Influenza is Normal in the Patients with X-Linked Agammaglobulinemia
Introduction Influenza virus is a potential cause of severe disease in the immunocompromised. X-linked agammaglobu-linemia (XLA) is a primary immunodeficiency characterized by the lack of immunoglobulin, B cells, and plasma cells, secondary to mutation in Bruton’s tyrosine kinase (Btk) gene
The Role of Interleukin-1 and Interleukin-18 in Pro-Inflammatory and Anti-Viral Responses to Rhinovirus in Primary Bronchial Epithelial Cells
Human Rhinovirus (HRV) is associated with acute exacerbations of chronic respiratory disease. In healthy individuals, innate viral recognition pathways trigger release of molecules with direct anti-viral activities and pro-inflammatory mediators which recruit immune cells to support viral clearance. Interleukin-1alpha (IL-1α), interleukin-1beta (IL-1β) and interleukin-18 (IL-18) have critical roles in the establishment of neutrophilic inflammation, which is commonly seen in airways viral infection and thought to be detrimental in respiratory disease. We therefore investigated the roles of these molecules in HRV infection of primary human epithelial cells. We found that all three cytokines were released from infected epithelia. Release of these cytokines was not dependent on cell death, and only IL-1β and IL-18 release was dependent on caspase-1 catalytic activity. Blockade of IL-1 but not IL-18 signaling inhibited up-regulation of pro-inflammatory mediators and neutrophil chemoattractants but had no effect on virus induced production of interferons and interferon-inducible genes, measured at both mRNA and protein level. Similar level of virus mRNA was detected with and without IL-1RI blockade. Hence IL-1 signaling, potentially involving both IL-1β and IL-1α, downstream of viral recognition plays a key role in induction of pro-inflammatory signals and potentially in recruitment and activation of immune cells in response to viral infection instigated by the epithelial cells, whilst not participating in direct anti-viral responses
Dobrava-Belgrade Hantavirus from Germany Shows Receptor Usage and Innate Immunity Induction Consistent with the Pathogenicity of the Virus in Humans
BACKGROUND: Dobrava-Belgrade virus (DOBV) is a European hantavirus causing hemorrhagic fever with renal syndrome (HFRS) in humans with fatality rates of up to 12%. DOBV-associated clinical cases typically occur also in the northern part of Germany where the virus is carried by the striped field mouse (Apodemus agrarius). However, the causative agent responsible for human illness has not been previously isolated. METHODOLOGY/PRINCIPAL FINDINGS: Here we report on characterization of a novel cell culture isolate from Germany obtained from a lung tissue of "spillover" infected yellow necked mouse (A. flavicollis) trapped near the city of Greifswald. Phylogenetic analyses demonstrated close clustering of the new strain, designated Greifswald/Aa (GRW/Aa) with the nucleotide sequence obtained from a northern German HFRS patient. The virus was effectively blocked by specific antibodies directed against β3 integrins and Decay Accelerating Factor (DAF) indicating that the virus uses same receptors as the highly pathogenic Hantaan virus (HTNV). In addition, activation of selected innate immunity markers as interferon β and λ and antiviral protein MxA after viral infection of A549 cells was investigated and showed that the virus modulates the first-line antiviral response in a similar way as HTNV. CONCLUSIONS/SIGNIFICANCE: In summary, our study reveals novel data on DOBV receptor usage and innate immunity induction in relationship to virus pathogenicity and underlines the potency of German DOBV strains to act as human pathogen
The Role of Indoleamine 2,3-Dioxygenase in LP-BPM5 Murine Retroviral Disease Progression
Indoleamine 2,3-dioxygenase (IDO) is an immunomodulatory intracellular enzyme involved in tryptophan degradation. IDO is induced during cancer and microbial infections by cytokines, ligation of co-stimulatory molecules and/or activation of pattern recognition receptors, ultimately leading to modulation of the immune response. LP-BM5 murine retroviral infection induces murine AIDS (MAIDS), which is characterized by profound and broad immunosuppression of T- and B-cell responses. Our lab has previously described multiple mechanisms regulating the development of immunodeficiency of LP-BM5-induced disease, including Programmed Death 1 (PD-1), IL-10, and T-regulatory (Treg) cells. Immunosuppressive roles of IDO have been demonstrated in other retroviral models, suggesting a possible role for IDO during LP-BM5-induced retroviral disease progression and/or development of viral load
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