Does the Tail Wag the Dog?: The Effect of Credit Default Swaps on Credit Risk

We use credit default swaps (CDS) trading data to demonstrate that the credit risk of reference firms, reflected in rating downgrades and bankruptcies, increases significantly upon the inception of CDS trading, a finding that is robust after controlling for the endogeneity of CDS trading. Additionally, distressed firms are more likely to file for bankruptcy if they are linked to CDS trading. Furthermore, firms with more “no restructuring” contracts than other types of CDS contracts (i.e., contracts that include restructuring) are more adversely affected by CDS trading, and the number of creditors increases after CDS trading begins, exacerbating creditor coordination failure in the resolution of financial distress.postprin

Case study on user knowledge and design knowledge in product form design

2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Inhibitory Effect of Polysaccharides from Scutellaria barbata D. Don on Invasion and Metastasis of 95-D Cells Lines via Regulation of C-MET and E-CAD Expressions

Purpose: To investigate the inhibitory effect of polysaccharides from Scutellaria barbata (PSB) on invasion and metastasis of lung cancer, and study the possible mechanism.Methods: PSB was extracted with water and by alcohol precipitation, and purified by DEAE-52 column chromatography. A highly invasive and metastatic lung carcinoma cell, 95-D cell line, was used for the study. Cell adhesion and invasion assays in vitro were performed to evaluate the anti-invasive and antimetastatic effects of PSB (50 - 200 μg/ml) on 95-D cell. Immunocytochemical staining and Western blot techniques were employed to study the regulatory effects of PSB on the expression of C-MET and ECAD.Results: The results indicate that PSB significantly inhibited cell invasion and migration of 95-D in a concentration-dependent manner (p < 0.05). The adhesion of 95-D cells to fibronectin was also inhibited by PSB (p < 0.05). The expression of C-MET and E-CAD in 95-D cells treated with PSB were significantly down-regulated and up-regulated, respectivelt (p < 0.05).Conclusion: Treatment with PSB can significantly inhibit the invasion and metastasis of 95-D cells in vitro, probably through the regulation of C-MET and E-CAD.Keywords: Polysaccharide, Scutellaria barbata, 95-D cell lines, Invasion, Metastasi

Biomechanical study of the funnel technique applied in thoracic pedicle screw replacement

Background: Funnel technique is a method used for the insertion of screw into thoracic pedicle.Aim: To evaluate the biomechanical characteristics of thoracic pedicle screw placement using the Funnel technique, trying to provide biomechanical basis for clinical application of this technology.Methods: 14 functional spinal units (T6 to T10) were selected from thoracic spine specimens of 14 fresh adult cadavers, and randomly divided into two groups, including Funnel technique group (n=7) and Magerl technique group (n=7). The displacement-stiffness and pull-out strength in all kinds of position were tested and compared.Results: Two fixed groups were significantly higher than that of the intact state (P<0.05) in the spinal central axial direction, compression, anterior flexion, posterior bending, lateral bending, axial torsion, but there were no significant differences between two fixed groups (P>0.05). The mean pull-out strength in Funnel technique group (789.09±27.33) was lower than that in Magerl technique group (P<0.05).Conclusions: The Funnel technique for the insertion point of posterior bone is a safe and accurate technique for pedicle screw placement. It exhibited no effects on the stiffness of spinal column, but decreased the pull-out strength of pedicle screw. Therefore, the funnel technique in the thoracic spine affords an alternative for the standard screw placement.Keywords: Thoracic; Pedicle screws; Biomechanics; Funnel techniqu

Association Between Atopic Dermatitis and Aging: Clinical Observations and Underlying Mechanisms

Peng-Yu Chen,1 Minxue Shen,2– 4 Sui-Qing Cai,1 Zhen-Wei Tang1 1Department of Dermatology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, People’s Republic of China; 2Department of Dermatology, Xiangya Hospital, Central South University, Changsha, 410008, People’s Republic of China; 3Hunan Engineering Research Center of Skin Health and Disease; Hunan Key Laboratory of Skin Cancer and Psoriasis (Xiangya Hospital), Changsha, 410008, People’s Republic of China; 4Department of Social Medicine and Health Management, Xiangya School of Public Health, Central South University, Changsha, 410078, People’s Republic of ChinaCorrespondence: Zhen-Wei Tang; Sui-Qing Cai, Email [email protected]; [email protected]: As one of the most prevalent chronic inflammatory skin diseases, atopic dermatitis (AD) increasingly affects the aging population. Amid the ongoing global aging trend, it’s essential to recognize the intricate relationship between AD and aging. This paper reviews existing knowledge, summarizing clinical observations of associations between AD and aging-related diseases in various systems, including endocrine, cardiovascular, and neurological. Additionally, it discusses major theories explaining the correlation, encompassing skin-mucosal barriers, systemic inflammation and stress, genes, signal transduction, and environmental and behavioral factors. The association between AD and aging holds significant importance, both in population and basic perspectives. While further research is warranted, this paper aims to inspire deeper exploration of inflammation/allergy-aging dynamics and the timely management of elderly patients with AD.Keywords: atopic dermatitis, aging, age-related diseases, clinical observations, mechanical theorie

The Granulin/Epithelin Precursor Abrogates the Requirement for the Insulin-like Growth Factor 1 Receptor for Growth in Vitro

3T3 cells null for the type 1 insulin-like growth factor receptor are refractory to stimulation by a variety of purified growth factors that are known to be required for the stimulation of other 3T3 cells. However, these cells, known as R- cells, grow in serum-supplemented medium and also in media conditioned by certain cell lines. We report here the purification of a growth factor that stimulates DNA synthesis (and growth) of R- cells. The growth factor, purified to homogeneity by SDS-polyacrylamide gel electrophoresis, was identified as the granulin/epithelin precursor by an accurate determination of the masses of endoproteinase Lys-C peptides using matrix-assisted laser desorption ionization mass spectrometry, followed by a data base search. The granulin/epithelin precursor is a little known growth factor, secreted by a variety of epithelial and hemopoietic cells. It is at present the only purified growth factor that can stimulate the growth of mouse embryo fibroblasts null for the type 1 insulin-like growth factor receptor

Inhibition of the tyrosine phosphatase SHP-2 suppresses angiogenesis in vitro and in vivo

Endothelial cell survival is indispensable to maintain endothelial integrity and initiate new vessel formation. We investigated the role of SHP-2 in endothelial cell survival and angiogenesis in vitro as well as in vivo. SHP-2 function in cultured human umbilical vein and human dermal microvascular endothelial cells was inhibited by either silencing the protein expression with antisense-oligodesoxynucleotides or treatment with a pharmacological inhibitor (PtpI IV). SHP-2 inhibition impaired capillary-like structure formation (p < 0.01; n = 8) in vitro as well as new vessel growth ex vivo (p < 0.05; n = 10) and in vivo in the chicken chorioallantoic membrane (p < 0.01, n = 4). Additionally, SHP-2 knock-down abrogated fibroblast growth factor 2 (FGF-2)-dependent endothelial proliferation measured by MTT reduction ( p ! 0.01; n = 12). The inhibitory effect of SHP-2 knock-down on vessel growth was mediated by increased endothelial apoptosis ( annexin V staining, p ! 0.05, n = 9), which was associated with reduced FGF-2-induced phosphorylation of phosphatidylinositol 3-kinase (PI3-K), Akt and extracellular regulated kinase 1/2 (ERK1/2) and involved diminished ERK1/2 phosphorylation after PI3-K inhibition (n=3). These results suggest that SHP-2 regulates endothelial cell survival through PI3-K-Akt and mitogen-activated protein kinase pathways thereby strongly affecting new vessel formation. Thus, SHP-2 exhibits a pivotal role in angiogenesis and may represent an interesting target for therapeutic approaches controlling vessel growth. Copyright (C) 2007 S. Karger AG, Basel

Multi-Patterned Dynamics of Mitochondrial Fission and Fusion in a Living Cell

Mitochondria are highly-dynamic organelles, but it is challenging to monitor quantitatively their dynamics in a living cell. Here we developed a novel approach to determine the global occurrence of mitochondrial fission and fusion events in living human epithelial cells (Hela) and mouse embryonic fibroblast cells (MEF). Distinct patterns of sequential events including fusion followed by fission (Fu-Fi), the so-called “kiss and run” model previously described, fission followed by fusion (Fi-Fu), fusion followed by fusion (Fu-Fu), and fission followed by fission (Fi-Fi) were observed concurrently. The paired events appeared in high frequencies with short lifetimes and large sizes of individual mitochondria, as compared to those for unpaired events. The high frequencies of paired events were found to be biologically significant. The presence of membrane uncoupler CCCP enhanced the frequency of paired events (from both Fu-Fi and Fi-Fu patterns) with a reduced mitochondrial size. Knock-out of mitofusin protein Mfn1 increased the frequency of fission with increased lifetime of unpaired events whereas deletion of both Mfn1 and Mfn2 resulted in an instable dynamics. These results indicated that the paired events were dominant but unpaired events were not negligible, which provided a new insight into mitochondrial dynamics. In addition to kiss and run model of action, our data suggest that, from a global visualization over an entire cell, multiple patterns of action appeared in mitochondrial fusion and fission

Comparison of sterols and fatty acids in two species of Ganoderma

<p>Abstract</p> <p>Background</p> <p>Two species of <it>Ganoderma, G. sinense </it>and <it>G. lucidum</it>, are used as <it>Lingzhi </it>in China. Howerver, the content of triterpenoids and polysaccharides, main actives compounds, are significant different, though the extracts of both <it>G. lucidum </it>and <it>G. sinense </it>have antitumoral proliferation effect. It is suspected that other compounds contribute to their antitumoral activity. Sterols and fatty acids have obvious bioactivity. Therefore, determination and comparison of sterols and fatty acids is helpful to elucidate the active components of <it>Lingzhi</it>.</p> <p>Results</p> <p>Ergosterol, a specific component of fungal cell membrane, was rich in <it>G. lucidum </it>and <it>G. sinense</it>. But its content in <it>G. lucidum </it>(median content 705.0 μg·g^-1, range 189.1-1453.3 μg·g^-1, n = 19) was much higher than that in <it>G. sinense </it>(median content 80.1 μg·g^-1, range 16.0-409.8 μg·g^-1, n = 13). Hierarchical clustering analysis based on the content of ergosterol showed that 32 tested samples of <it>Ganoderma </it>were grouped into two main clusters, <it>G. lucidum </it>and <it>G. sinense</it>. Hierarchical clustering analysis based on the contents of ten fatty acids showed that two species of <it>Ganoderma </it>had no significant difference though two groups were also obtained. The similarity of two species of <it>Ganoderma </it>in fatty acids may be related to their antitumoral proliferation effect.</p> <p>Conclusions</p> <p>The content of ergosterol is much higher in <it>G. lucidum </it>than in <it>G. sinense</it>. Palmitic acid, linoleic acid, oleic acid, stearic acid are main fatty acids in <it>Ganoderma </it>and their content had no significant difference between <it>G. lucidum </it>and <it>G. sinense</it>, which may contribute to their antitumoral proliferation effect.</p

Processing and characterization of chitosan microspheres to be used as templates for layer-by-layer assembly

Chitosan (Ch) microspheres have been developed by precipitation method, cross-linked with glutaraldehyde and used as a template for layer-by-layer (LBL) deposition of two natural polyelectrolytes. Using a LBL methodology, Ch microspheres were alternately coated with hyaluronic acid (HA) and Ch under mild conditions. The roughness of the Ch-based crosslinked microspheres was characterized by atomic force microscopy (AFM). Morphological characterization was performed by environmental scanning electron microscopy (ESEM), scanning electron microscopy (SEM) and stereolight microscopy. The swelling behaviour of the microspheres demonstrated that the ones with more bilayers presented the highest water uptake and the uncoated cross-linked Ch microspheres showed the lowest uptake capability. Microspheres presented spherical shape with sizes ranging from 510 to 840 lm. ESEM demonstrated that a rougher surface with voids is formed in multilayered microspheres caused by the irregular stacking of the layers. A short term mechanical stability assay was also performed, showing that the LBL procedure with more than five bilayers of HA/Ch over Ch cross-linked microspheres provide higher mechanical stability