The Preparation and Performance of a New Polyurethane Vascular Prosthesis

We investigated the performance of small-caliber polyurethane (PU) small-diameter vascular prosthesis generated using the electrospinning technique. PU was electrospun into small-diameter, small-caliber tubular scaffolds for potential application as vascular grafts. We investigated the effects of electrospinning conditions (solution concentration, mandrel rotation speed) on the microstructure and porosity of the scaffolds for the purpose of preparing scaffolds with optimum microstructures and properties. We evaluated the mechanical properties of the scaffolds by tensile tests and the cytotoxicity of the PU small-diameter, small-caliber PU synthetic vascular graft by the MTT assay. The adhesion of endothelial cells to the PU scaffold was characterized by Hoechst staining and fluorescence microscopy, and we measured endothelial cell proliferation on the PU scaffold by the CCK-8 assay. We analyzed the prosthesis microstructure and endothelial cell morphology using scanning electron microscopy. With increasing PU concentration in the electrospinning solution, the fiber diameter of the vascular graft increased and the porosity decreased. In addition, with increasing electrospinning time, the wall thickness increased and the porosity decreased. We found that regular fiber orientation can be obtained by adjusting the rotation speed of the mandrel. Cell proliferation was not inhibited as the small-caliber PU synthetic vascular grafts showed little cytotoxicity. The endothelial cells had faster adherence to the PU scaffolds than to the PTFE surface during the initial contact. After prolonged cell culture, significantly higher endothelial cell proliferation rate was observed in the PU scaffold groups than the PTFE group. We obtained small-caliber PU vascular grafts with optimal fiber arrangement, excellent mechanical properties, and optimal biocompatibility by optimizing the electrospinning conditions. This study provides in vitro biocompatibility data that is helpful for the clinical application of the PU small-diameter, small-caliber PU vascular grafts.     

Surface Properties and Corrosion Behavior of Co–Cr Alloy Fabricated with Selective Laser Melting Technique

We sought to study the corrosion behavior and surface properties of a commercial cobalt–chromium (Co–Cr) alloy which was fabricated with selective laser melting (SLM) technique. For this purpose, specimens were fabricated using different techniques, such as SLM system and casting methods. Surface hardness testing, microstructure observation, surface analysis using X-ray photoelectron spectroscopy (XPS) and electrochemical corrosion test were carried out to evaluate the corrosion properties and surface properties of the specimens. We found that microstructure of SLM specimens was more homogeneous than that of cast specimens. The mean surface hardness values of SLM and cast specimens were 458.3 and 384.8, respectively; SLM specimens showed higher values than cast ones in hardness. Both specimens exhibited no differences in their electrochemical corrosion properties in the artificial saliva through potentiodynamic curves and EIS, and no significant difference via XPS. Therefore, we concluded that within the scope of this study, SLM-fabricated restorations revealed good surface properties, such as proper hardness, homogeneous microstructure, and also showed sufficient corrosion resistance which could meet the needs of dental clinics.     

2,3,4′,5-Tetrahydroxystilbene-2-O-β-D-glucoside Suppresses Expression of Adhesion Molecules in Aortic Wall of Dietary Atherosclerotic Rats and Promonocytic U937 Cells

We sought to investigate whether TSG suppressed the ICAM-1/VCAM-1 expression in dietary atherosclerotic rats and in Ox-LDL-induced U937 cells. For this purpose, 60 male Sprague–Dawley rats were randomly-and-equally divided into six groups. Atherosclerosis was induced by feeding rats a hyperlipidemic diet. TSG (120, 60 or 30 mg/kg/day) was administered by oral gavage. Simvastatin (2 mg/kg/day) was administered as positive control whereas physiological saline (0.9 % NaCl) served as untreated control. After 12 weeks, rats were euthanized by ethyl carbonate (1,200 mg/kg) and aortic wall samples were collected. Besides, U937 cells were stimulated for 48 h by Ox-LDL (80 μg/mL) with and without TSG (120, 60, 30 μg/L) or simvastatin (100 μg/L). ICAM-1/VCAM-1 mRNA expression was determined by RT-PCR and protein expression was detected by immunohistochemistry and/or western blotting. The data show that ICAM-1/VCAM-1 mRNA/protein expression was significantly enhanced in atherosclerotic aortas compared with normal diet group. Ox-LDL-induced ICAM-1/VCAM-1 mRNA/protein expression in U937 cells. Importantly, TSG significantly inhibited ICAM-1/VCAM-1 expression in atherosclerotic aortas in a dose-dependent manner. TSG-pretreatment also inhibited ICAM-1/VCAM-1 expression in Ox-LDL-induced U937 cells. Therefore, we concluded that TSG suppressed the expression of adhesion (ICAM-1/VCAM-1) molecules both in vivo (in aortic wall of dietary atherosclerotic rats) and in vitro (U937 cells).     

Cloning of the crustacean hyperglycemic hormone and evidence for molt-inhibiting hormone within the central nervous system of the blue crab Portunus pelagicus

The crustacean X-organ–sinus gland (XO–SG) complex controls molt-inhibiting hormone (MIH) production, although extra expression sites for MIH have been postulated. Therefore, to explore the expression of MIH and distinguish between the crustacean hyperglycemic hormone (CHH) superfamily, and MIH immunoreactive sites (ir) in the central nervous system (CNS), we cloned a CHH gene sequence for the crab Portunus pelagicus (Ppel-CHH), and compared it with crab CHH-type I and II peptides. Employing multiple sequence alignments and phylogenic analysis, the mature Ppel-CHH peptide exhibited residues common to both CHH-type I and II peptides, and a high degree of identity to the type-I group, but little homology between Ppel-CHH and Ppel-MIH (a type II peptide). This sequence identification then allowed for the use of MIH antisera to further confirm the identity and existence of a MIH-ir 9 kDa protein in all neural organs tested by Western blotting, and through immunohistochemistry, MIH-ir in the XO, optic nerve, neuronal cluster 17 of the supraesophageal ganglion, the ventral nerve cord, and cell cluster 22 of the thoracic ganglion. The presence of MIH protein within such a diversity of sites in the CNS, and external to the XO–SG, raises new questions concerning the established mode of MIH action.     

Study on the Interaction Mechanism of 2‐Aminoanthraquinone with Calf Thymus DNA

By utilizing multispectrosopic techniques, the toxic interaction of 2‐aminoanthraquinone (2‐AAQ) with calf thymus deoxyribonucleic acid (ctDNA) was investigated in vitro under simulated physiological conditions. The experimental results proved that 2‐AAQ has a toxic interaction with ctDNA. The binding capacity of DNA with 2‐AAQ is diminishing as the pH value of system increasing in the optimization of experimental condition. Moreover we selected pH 7.4, which is nearly physiological condition to enhance the practical significance. According to the Stern–Volmer equation, the quenching was the static quenching process. And the quenching constant can be derived from the fluorescence quenching spectrogram. Ultraviolet absorption spectra and the change in the fluorescence intensity at different ionic strengths further indicated that there was electrostatic binding between 2‐AAQ and ctDNA. The circular dichroism experiment showed that the DNA conformation varied from B to A conformation. The basic group enhanced after 2‐AAQ embedding. The double helix is more compact, and the DNA conformation changes. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:272‐278, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21487     

Development of tree-ring maximum latewood density chronologies for the western Tien Shan Mountains,China: Influence of detrending method and climate response

Three tree-ring maximum latewood density chronologies were developed from high elevation Picea schrenkiana sites in the western Tien Shan Mountains using different detrending methods. The new chronologies extend back to the early 16th and late 17th centuries, and contain significant late spring and summer temperature signals, respectively. An assessment of varying detrending methods and band-pass filtering the chronologies revealed only slightly differing low frequency trends retained in the maximum latewood densities. The distance between sampling sites and the varying seasonality of limiting climatic factors are identified as key drivers affecting the correlation among the maximum latewood density records in the study region. The new chronologies represent reliable proxies of high elevation late spring and summer temperature variability in an area underrepresented by such data, and are ready-to-use for network analyses addressing longer-term climate variations in eastern central Asia.     

Derivation and characterization of cell cultures from the skin of the Indo-Pacific humpback dolphin Sousa chinensis

The marine mammalian Indo-Pacific humpback dolphin, once widely lived in waters of the Indian to western Pacific oceans, has become an endangered species. The individual number of this dolphin has significantly declined in recent decades, which raises the concern of extinction. Direct concentration on laboratorial conservation of the genetic and cell resources should be paid to this marine species. Here, we report the successful derivation of cell lines form the skin of Indo-Pacific humpback dolphin. The cell cultures displayed the characteristics of fibroblast in morphology and grew rapidly at early passages, but showed obvious growth arrest at higher passages. The karyotype of the cells consisted of 42 autosomes and sex chromosomes X and Y. The immortalized cell lines obtained by forced expression of the SV40 large T-antigen were capable of proliferation at high rate in long-term culture. Immortalization and long-term culture did not cause cytogenetically observable abnormality in the karyotype. The cell type of the primary cultures and immortalized cell lines were further characterized as fibroblasts by the specific expression of vimentin. Gene transfer experiments showed that exogenetic genes could be efficiently delivered into the cells by both plasmid transfection and lentivirus infection. The cells derived from the skin of the Indo-Pacific humpback dolphin may serve as a useful in vitro system for studies on the effects of environmental pollutants and pathogens in habitats on the dolphin animals. More importantly, because of their high proliferation rate and susceptibility to lentivirus, these cells are potential ideal materials for generation of induced pluripotent stem cells.     

Carbenoxolone Blocks Endotoxin-Induced Protein Kinase R (PKR) Activation and High Mobility Group Box 1 (HMGB1) Release

The pathogen- and damage-associated molecular patterns (for example, bacterial endotoxin and adenosine 5′-triphosphate [ATP]) activate the double-stranded RNA-activated protein kinase R (PKR) to trigger the inflammasome-dependent high mobility group box 1 (HMGB1) release. Extracellular ATP contributes to the inflammasome activation through binding to the plasma membrane purinergic P2X₇ receptor (P2X₇R), triggering the opening of P2X₇R channels and the pannexin-1 (panx-1) hemichannels permeable for larger molecules up to 900 daltons. It was previously unknown whether panx-1 channel blockers can abrogate lipopolysaccharide (LPS)-induced PKR activation and HMGB1 release in innate immune cells. Here we demonstrated that a major gancao (licorice) component (glycyrrhizin, or glycyrrhizic acid) derivative, carbenoxolone (CBX), dose dependently abrogated LPS-induced HMGB1 release in macrophage cultures with an estimated IC₅₀ ≈ 5 μmol/L. In an animal model of polymicrobial sepsis (induced by cecal ligation and puncture [CLP]), repetitive CBX administration beginning 24 h after CLP led to a significant reduction of circulating and peritoneal HMGB1 levels, and promoted a significant increase in animal survival rates. As did P2X₇R antagonists (for example, oxidized ATP, oATP), CBX also effectively attenuated LPS-induced P2X₇R/panx-1 channel activation (as judged by Lucifer Yellow dye uptake) and PKR phosphorylation in primary peritoneal macrophages. Collectively, these results suggested that CBX blocks LPS-induced HMGB1 release possibly through impairing PKR activation, supporting the involvement of PKR in the regulation of HMGB1 release.     

A novel peptide specifically targeting ovarian cancer identified by in vivo phage display

Discovery of peptide ligands that can target human ovarian cancer and deliver chemotherapeutics offers new opportunity for cancer therapy. The advent of phage‐displayed peptide library facilitated the screening of such peptides. In vivo screening that set in a microanatomic and functional context was applied in our study, and a novel peptide WSGPGVWGASVK targeting ovarian cancer was isolated. The phage clone PC3‐1 displaying peptide WSGPGVWGASVK can gain effective access to accumulate in the tumor sites after intravenous injection while reducing its accumulation in normal organs. Positive immunostaining of PC3‐1 was located in both sites of tumor cells and tumor blood vessels, which resulted in a diffuse binding pattern through the tumor. In vitro study results confirmed the capability of peptide WSGPGVWGASVK binding to and being internalized by both tumor cells and angiogenic endothelial cells. Flow cytometry analysis revealed that the peptide bound to SKOV3 cells with Kd value of 5.43 ± 0.4 μM. Taken together, it suggested that peptide WSGPGVWGASVK is a lead candidate for delivering therapeutics to penetrate into tumors. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.