A study of vascular smooth muscle cell function under cyclic mechanical loading in a polyurethane scaffold with optimized porosity

High porosity and pore interconnectivity are important features of a successful tissue engineering scaffold. The objective of this work was to optimize the pore interconnectivity and to increase the porosity of an elastomeric degradable/polar/hydrophobic/ionic (D-PHI) polyurethane porous scaffold while maintaining its mechanical integrity in order to allow for the transfer of mechanical stimulus to vascular smooth muscle cells (VSMCs) seeded onto the scaffold. The effect of varying porogen (sodium bicarbonate (salt) and polyethylene glycol (PEG)) composition and concentration on the mechanical properties, degree of swelling and porosity of the scaffolds was investigated. It was found that the use of 10 wt.% PEG and 65 wt.% salt in scaffold fabrication (D-PHI-75T) resulted in micropore (1–5 μm) formation, a high porosity (79 ± 3%) and mechanical properties (elastic modulus = 0.16 ± 0.03 MPa, elongation-at-yield = 31 ± 5% and tensile strength = 0.04 ± 0.01 MPa) required to withstand the physiologically relevant mechanical strain experienced by VMSCs in vivo. This study also investigated the influence of cyclic mechanical strain (CMS) on select molecular markers of A10 VSMCs when seeded into the optimized D-PHI scaffold. To study the interaction of A10 cells with the optimized D-PHI-75T scaffold in the presence of uniaxial strain (10%, 1 Hz), a CMS bioreactor was designed and constructed. Molecular marker studies showed a statistical increase in DNA mass and calponin expression after 3 and 7 days of CMS when compared to static samples, indicating that the translation of mechanical loading from the novel polyurethane elastomeric scaffold onto VSMCs will be important to consider with regard to modulating cell phenotype.     

Differential expression of nucleostemin,a stem cell marker,and its variants in different types of brain tumors

Nucleostemin (NS) is implicated in the control of stem and cancer cell proliferation. In the present study, we have examined the expression of NS and its spliced variants in various brain tumors. Total RNA was extracted from 59 brain tumor samples, and the expression of different NS spliced variants was measured by semi‐quantitative RT‐PCR. The subcellular distribution of NS protein in brain tumors was further examined by immunohistochemistry. Furthermore, to decipher the potential involvement of NS in brain tumorogenesis, its expression was knocked‐down by means of RNA interference (RNAi) in two malignant glioma (U‐87MG and A172), one astrocytoma (1321N1) and one medulloblastoma (DAOY) cell lines. The alterations in cell‐cycle progression of the treated cells were then analyzed by flow cytometry. Our data revealed that NS and its variants are widely expressed in different types of brain tumors. Among the NS spliced variants, variant “1” and variant “3” were detected in the majority of tumor samples, whereas variant “2” was only detectable in few samples. Moreover, the intensity of the expression was correlated with the grade of the tumors (P < 0.05). Accordingly, the expression was much higher in glial tumors compared to that of meningiomas. As expected, a nucleolar/nucleoplasmic localization of NS protein was observed in the examined tumor samples. RNAi results revealed a significant reduction of NS expression along with a moderate blockade of the cell cycle in G₂/M and S phases of NS‐siRNA treated cells. All in all, our data suggest a potential role for NS in tumorogenesis of brain cancers. © 2010 Wiley‐Liss, Inc.     

Substance P (SP) induces expression of functional corticotropin-releasing hormone receptor-1 (CRHR-1) in human mast cells

Corticotropin-releasing hormone (CRH) is secreted under stress and regulates the hypothalamic-pituitary-adrenal axis. However, CRH is also secreted outside the brain where it exerts proinflammatory effects through activation of mast cells, which are increasingly implicated in immunity and inflammation. Substance P (SP) is also involved in inflammatory diseases. Human LAD2 leukemic mast cells express only CRHR-1 mRNA weakly. Treatment of LAD2 cells with SP (0.5-2?μM) for 6?hours significantly increases corticotropin-releasing hormone receptor-1 (CRHR-1) mRNA and protein expression. Addition of CRH (1?μM) to LAD2 cells, which are "primed" with SP for 48?hours and then washed, induces synthesis and release of IL-8, tumor necrosis factor (TNF), and vascular endothelial growth factor (VEGF) 24?hours later. These effects are blocked by pretreatment with an NK-1 receptor antagonist. Treatment of LAD2 cells with CRH (1?μM) for 6?hours induces gene expression of NK-1 as compared with controls. However, repeated stimulation of mast cells with CRH (1?μM) leads to downregulation of CRHR-1 and upregulation in NK-1 gene expression. These results indicate that SP can stimulate mast cells and also increase expression of functional CRHR-1, whereas CRH induces NK-1 gene expression. These results may explain CRHR-1 and NK-1 expression in lesional skin of psoriatic patients.     

临床表现似视网膜母细胞瘤的脉络膜黑色素细胞瘤1例(英文)

我们报道罕见的脉络膜黑色素细胞瘤1例,以视网膜母细胞瘤之诊断行眼球内容物剜除术。患儿14mo,以左眼外斜视约10mo主诉就诊。眼科检查及影像学检查显示视网膜脱离并钙化病灶。患儿诊断为视网膜母细胞瘤,患眼行眼球内容物剜除术。组织病理学检查显示肿瘤细胞体积大,多面体型,核小,胞浆含大量黑色素颗粒,提示脉络膜及睫状体黑素细胞瘤之诊断。以往有脉络膜及睫状体黑色素细胞瘤表现类似与恶性黑素瘤的报道,但是,黑色素细胞瘤表现为钙化病灶及视网膜脱离,被误诊为视网膜母细胞瘤,此病例罕见,以往未见报道。     

Serum biochemical parameters of Huso huso

Serum biochemical parameters are important aspects in the management of endangered species such as Huso huso. The values of these parameters can be used for confirming the sex and any changes in the quality of waters and related soils. Serum samples of 15 H. huso fish were analysed and their serum parameter values were determined as mean±SD in both sexes. Age, weight, total length and fork length were the same between groups. We compared the levels of calcium (Ca; 2.13 ± 0.69–2.37 ± 0.38 mmol/l), total protein (TOP; 4.51 ± 1–5.50 ± 0.94 mg/dl), blood urea nitrogen (BUN; 1.32 ± 0.23–1.35 ± 0.31 mmol/l), albumin (Alb; 0.88 ± 0.18–1.26 ± 0.29 mg/dl), globulin (Glb; 3.63 ± 0.84–4.5 ± 0.69 mg/dl), uric acid (UA; 1.66 ± 0.18–1.79 ± 0.27 mmol/l), creatinine (CREA; 30.48 ± 4.31–30.48 ± 6.10 mmol/l), phosphorous (P; 2.18 ± 0.38–2.91 ± 0.67 mmol/l), magnesium (Mg; 1.15 ± 0.26–1.51 ± 0.35 mmol/l), glucose (Glc; 3.42 ± 0.84–6.69 ± 1.54 mmol/l), alkaline phosphatase (ALP; 4.48 ± 1.82–5 ± 1.04 IU/l) and amylase (156.19 ± 34.07–166.25 ± 64.27-IU/l). We have shown that there were no differences in the Ca, TOP, BUN, UA, CREA, Mg, ALP and amylase between sexes. However, male fish have higher Glc, P, Alb and Glb than females.