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Background: In the process of bone defective reparation and engineered bone tissue construction, osteoblasts are adhered to the surface of the scaffold materials and impart the external mechanical load to the osteoblasts. So, the dynamic mechanical property of the scaffolds play an important role in the bone tissue repair and it is valuable to research. Material type and the architectural design of scaffolds are also important to facilitate cell and tissue growth. The aim of this study was to prepare a kind of material with good pore connectivity and analyze its dynamic mechanical property.Methods: Fabrication and characterization of micro-hydroxyapatite(m-HA)/chitosan(CS) polymer composite scaffolds with well interconnected spherical pore architectures were reports. Micro-HA was prepared by being calcined and ball milled. Paraffin spheres in the range of 160-330 µm were fabricated with a dispersion method and used as the porogen in the fabrication of the scaffolds. Polymer scaffolds were fabricated by the technique of compression molding and particulate leaching method. The effects of the porogen content on the properties of the scaffolds were studied.Results: With the increase of porogen, the pore of the scaffolds increased and became interconnected. Cyclic loading of three scaffolds were tested with 10 % strain under four levels of loading frequency, 0.1, 0.5, 1 and 1.5 Hz. The porous composite scaffolds exhibited a viscosity-elastic behaviour with a maximum stress of 3-4 kPa. At each frequency, modulus value is decreased with the paraffin microspheres content, but there was no significance difference in the peak stress of the three samples. All the samples tested displayed clear hysteresis loops. There was no significance difference in the peak hysteresis of the three samples, and the hysteresis difference values between the sixth compression cycle and the initial cycle for three samples was similar, with no statistically significant differences.Conclusions: Micro-HA/CS composite scaffolds with interconnected spherical macropores were fabricated using pherical paraffin as porogen. The porous composite scaffolds exhibited a viscosity-elastic behaviour with good repeatability. It is benefit to study the influence of the mechanical load on the cell of the scaffold. [ABSTRACT FROM AUTHOR]

Background: Porcine reproductive and respiratory syndrome (PRRS) remains a major threat to swine industry all over the world. The aim of this study was to investigate the mechanism of pathogenesis and immune responses caused by a highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV)., Results: All piglets experimentally infected with a HP-PRRSV TJ strain virus developed typical clinical signs of PRRS. The percentages of CD3 + , CD4 + , and CD8 + lymphocytes significantly decreased in the infected group as compared to the uninfected control animals (p < 0.01). Total WBC dropped in the infected animals during the experiment. The level of ELISA antibody against PRRSV increased in 7-10 days after infection and then started to decline. Pathological observations demonstrated various degree lesions, bleeding and necrosis in the lungs of the infected piglets., Conclusions: These results clearly indicated that HP-PRRSV TJ strain infection would activate host humoral immune response at the early period post infection and cause severe pathological damages on lungs and inhibit cellular immune response after infection.

Background: Hypoxia induced by antiangiogenic agents is linked to the generation of cancer stem cells (CSCs) and treatment failure through unknown mechanisms. The generation of endothelial cell-independent microcirculation in malignant tumors is defined as tumor cell vasculogenic mimicry (VM). In the present study, we analyzed the effects of an antiangiogenic agent on VM in triple-negative breast cancer (TNBC)., Methods: Microcirculation patterns were detected in patients with TNBC and non-TNBC. Tientsin Albino 2 (TA2) mice engrafted with mouse TNBC cells and nude mice engrafted with human breast cancer cell lines with TNBC or non-TNBC phenotypes were administered sunitinib and analyzed to determine tumor progression, survival, microcirculation, and oxygen concentration. Further, we evaluated the effects of hypoxia induced with CoCl2 and the expression levels of the transcription factor Twist1, in the presence or absence of a Twist siRNA, on the population of CD133(+) cells and VM in TNBC and non-TNBC cells., Results: VM was detected in 35.8 and 17.8% of patients with TNBC or with non-TNBC, respectively. The growth of tumors in TNBC and non-TNBC-bearing mice was inhibited by sunitinib. The tumors in TA2 mice engrafted with mouse TNBCs and in mice engrafted a human TNBC cell line (MDA-MB-231) regrew after terminating sunitinib administration. However, this effect was not observed in mice engrafted with a non-TNBC tumor cell line. Tumor metastases in sunitinib-treated TA2 mice was accelerated, and the survival of these mice decreased when sunitinib was withdrawn. VM was the major component of the microcirculation in sunitinib-treated mice with TNBC tumors, and the population of CD133+ cells increased in hypoxic areas. Hypoxia also induced MDA-MB-231 cells to express Twist1, and CD133(+) cells present in the MDA-MB-231 cell population induced VM after reoxygenation. Moreover, hypoxia did not induce MDA-MB-231 cells transfected with an sh-Twist1 siRNA cell to form VM and generate CD133(+) cells. Conversely, hypoxia induced MCF-7 cells transfected with Twist to form VM and generate CD133+ cells., Conclusions: Sunitinib induced hypoxia in TNBCs, and Twist1 expression induced by hypoxia accelerated VM by increasing population of CD133(+) cells. VM was responsible for the regrowth of TNBCs sunitinib administration was terminated.

Background: The aim of this study was to investigate prognostic value of excision repair cross-complementing 1 (ERCC1), BCL2-associated athanogene (BAG-1), the breast and ovarian cancer susceptibility gene 1 (BRCA1), ribonucleotide reductase subunit M1 (RRM1) and class III β-tubulin (TUBB3) in patients with non-small cell lung cancer (NSCLC) who received platinum- based adjuvant chemotherapy., Methods: Messenger RNA expressions of these genes were examined in 85 tumor tissues and 34 adjacent tissue samples using semi-quantitative RT-PCR. The expressions of these five genes were analyzed in relation to chemotherapy and progression-free survival (PFS) and overall survival (OS). Seventy-four patients were enrolled into chemotherapy., Results: Patients with ERCC1 or BAG-1 negative expression had a significantly longer PFS (P = 0.001 and P = 0.001) and OS (P = 0.001 and P = 0.001) than those with positive expression. Patients with negative ERCC1 and BAG-1 expression benefited more from platinum regimen (P = 0.001 and P = 0.002). Patients with BRCA1 negative expression might have a longer OS (P = 0.052), but not PFS (P = 0.088) than those with BRCA1 positive expression. A significant relationship was observed between the mRNA expression of ERCC1 and BAG-1 (P = 0.042). In multivariate analysis, ERCC1 and BAG-1 were significantly favorable factors for PFS (P = 0.018 and P = 0.017) and OS (P = 0.027 and P = 0.022)., Conclusions: ERCC1 and BAG-1 are determinants of survival after surgical treatment of NSCLC, and its mRNA expression in tumor tissues could be used to predict the prognosis of NSCLC treated by platinum.