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Find video protocols related to scientific articles indexed in Pubmed.
Inverse correlation of phospho-KDR/Flk-1 expression and stage of colorectal cancer: implication of the significance of neoangiogenesis in activated VEGFR-2 expressing early stage colorectal adenocarcinomas.
Pol J Pathol
PUBLISHED: 11-06-2014
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The activation of vascular endothelial cell growth factor receptors (VEGFRs) plays an essential role in cancer progression. In this study, we investigated the expression of phosphorylated VEGFR-2 (or phospho-KDR/Flk-1), the activated form of VEGFR-2, in human colorectal adenomas and colorectal adenocarcinomas. Phospho-KDR/Flk-1 showed weak expression in the normal colorectal tissue. Phospho-KDR/Flk-1 was mainly stained in the cytoplasm of colorectal adenomas, and was stained in both the cytoplasm and nuclei colorectal adenocarcinomas. There was no indication of increased phospho-KDR/Flk-1 expression in the colorectal adenocarcinomas, as compared to that of colorectal adenomas. Furthermore, there was an inverse relationship of phospho-KDR/Flk-1 expression with cancer stage (p < 0.0001), lymph node metastasis (p = 0.011), and distant metastasis (p = 0.021) of the colorectal adenocarcinomas. Our results indicate that early stage colorectal adenocarcinomas with highly activated (phosphorylated) VEGFR-2 expression may indicate the significance of neoangiogenesis of the tumors.
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Full-frame projection displays using a liquid-crystal-on-silicon spatial light modulator for beam shaping and speckle suppression.
Appl Opt
PUBLISHED: 10-17-2014
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This paper presents a full-frame laser projection display system in which a spatial light modulator (SLM) is used for beam shaping and speckle suppression. Phase-only computer-generated holograms (CGHs) are used to transform a cross section of the incident laser beam into a square nearly the same size as that of the display device. Under different initial conditions, the diffraction patterns generated by the CGHs possess identical intensity distributions but differ with regard to random phase distribution. Image speckles can be suppressed via the temporal addition of diffraction patterns from the CGHs when displayed by the SLM. The addition of 16 speckled images resulted in speckle suppression ratios of 0.290 in simulations and 0.345 under experimental conditions. Not only were the speckles suppressed, but the quality of the overall image was also improved considerably. The proposed approach presents a simple design with low power consumption and stable display architecture for application in pico-projectors.
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Laser speckle reduction by phase range limited computer generated hologram in laser projection display system.
Appl Opt
PUBLISHED: 10-17-2014
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The speckle phenomenon is an annoyance in laser projection display systems. We propose a novel speckle suppression method that utilizes the interference concept on a pixel point, which reduces the speckle contrast (SC) of the project image by limiting the phase distribution range in the optical field. The SC formula is derived in the uniform interval phase range for partially developed speckle conditions, showing that the SC can be lowered by lessening the phase range limitation. In the ideal simulation model, the SC can be reduced from 98.77% to 0% as the phase range limitation varies from 2? to 0. The phase range limitation model is a novel method using a computer generated hologram to provide beam shaping and phase limitation. In a more realistic simulation model, the SC is reduced from 99.18% to 16.68%.
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Epstein-Barr virus BALF3 mediates genomic instability and progressive malignancy in nasopharyngeal carcinoma.
Oncotarget
PUBLISHED: 09-28-2014
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Nasopharyngeal carcinoma (NPC) is a head and neck cancer prevalent throughout Southern China and Southeast Asia. Patient death following relapse after primary treatment remains all too common but the cause of NPC relapse is unclear. Clinical and epidemiological studies have revealed the high correlation among NPC development, Epstein-Barr virus (EBV) reactivation and host genomic instability. Previously, recurrent EBV reactivation was shown to cause massive genetic alterations and enhancement of tumor progression in NPC cells and these may be required for NPC relapse. Here, EBV BALF3 has the ability to induce micronuclei and DNA strand breaks. After recurrent expression of BALF3 in NPC cells, genomic copy number aberrations, determined by array-based comparative genomic hybridization, had accumulated to a significant extent and tumorigenic features, such as cell migration, cell invasion and spheroid formation, increased with the rounds of induction. In parallel experiments, cells after highly recurrent induction developed into larger tumor nodules than control cells when inoculated into NOD/SCID mice. Furthermore, RNA microarrays showed that differential expression of multiple cancer capability-related genes and oncogenes increased with recurrent BALF3 expression and these changes correlated with genetic aberrations. Therefore, EBV BALF3 is a potential factor that mediates the impact of EBV on NPC relapse.
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Nurses' reflections on good nurse traits: Implications for improving care quality.
Nurs Ethics
PUBLISHED: 09-24-2014
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Good nurses show concern for patients by caring for them effectively and attentively to foster their well-being. However, nurses cannot be taught didactically to be "good" or any trait that characterizes a good nurse. Nurses' self-awareness of their role traits warrants further study.
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Predictors for resectability and survival in locally advanced pancreatic cancer after gemcitabine-based neoadjuvant therapy.
BMC Surg
PUBLISHED: 09-10-2014
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To evaluate the predictors for resectability and survival of patients with locally advanced pancreatic cancer (LAPC) treated with gemcitabine-based neoadjuvant therapy (GBNAT).
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Fabrication of biodegradable polyurethane microspheres by a facile and green process.
J. Biomed. Mater. Res. Part B Appl. Biomater.
PUBLISHED: 08-28-2014
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Two different compositions of water-based biodegradable polyurethane (PU) in the form of homogeneous nanoparticles (NPs) were synthesized using biodegradable polyesters as the soft segment. The first PU (PU01) was based on poly(?-caprolactone) (PCL) diol and the second PU (PU02) was based on 40% PCL diol and 60% polyethylene butylene adipate diol. The PU NP dispersions with different solid contents were sprayed into liquid nitrogen and resuspended in water to generate elastic microspheres (50-60 µm) with different nanoporosities. In vitro degradation analysis revealed that microspheres of PU02 (i.e., PU02 MS) degraded faster than those of PU01 (PU01 MS). Methylene blue was encapsulated during microsphere formation and the release was investigated. Microspheres made from a lower content (10%) of PU02 dispersion (i.e., PU02 MS_10) showed a greater burst release of methylene blue in 6 h, whereas those made from a higher content (30%) of PU01 dispersion (i.e., PU01 MS_30) revealed a prolonged release with a significantly lower burst release. Biocompatibility evaluation using L929 fibroblasts demonstrated that cells were attached and proliferated on microspheres after 24 h. On the other hand, microspheres may further self-assemble into films and scaffolds. Surface modification of microspheres by chitosan may modify the self-assembly behavior of microspheres. Microspheres could be stacked to form scaffolds with different macroporosities. Fibroblasts were successfully seeded and grown in the microsphere-stacked scaffolds. We concluded that the biodegradable and elastic microspheres may be facilely produced from a green and sustainable process with potential applications in drug release and three-dimensional cell culture. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2014.
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Collaborative Mother-Toddler Communication and Theory of Mind Development at Age 4.
J Appl Dev Psychol
PUBLISHED: 08-19-2014
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Focusing on social pragmatics, this longitudinal study investigated the contribution of mother-toddler collaborative communication to theory of mind (ToM) development at age 4. At age 2½, 78 toddlers' (42 boys) and their mothers were observed during pretend play. At age 4, children were tested using 4 false belief understanding tasks. Both mothers and toddlers engaged in more collaborative (inform, guide/request, and support/confirm) than non-collaborative communication acts. Other-focused collaborative acts of support/confirm by mothers and toddlers predicted children's false belief understanding, even after controlling for 5 covariates. In addition, as active agents in their own ToM development, the contribution of toddlers' collaborative acts to false belief understanding was independent of their mothers. Finally, the way toddlers and their mothers co-constructing their communication mattered. Only when toddlers engaged in high levels of collaborative acts, the mothers' high levels of collaborative acts demonstrated a positive effect on children's ToM development. The applied implications of these findings were discussed.
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Nestin predicts a favorable prognosis in early ampullary adenocarcinoma and functions as a promoter of metastasis in advanced cancer.
Oncol. Rep.
PUBLISHED: 08-14-2014
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Nestin exhibits stemness characteristics and is overexpressed in several types of cancers. Downstream signaling of nestin [cyclin-dependent kinase 5 (CDK5) and Ras-related C3 botulinum toxin substrate 1 (Rac1)] functions in cancer to modulate cellular behaviors. We studied the function of nestin in ampullary adenocarcinoma. Immunohistochemistry (IHC), reverse transcription-polymerase chain reaction, and cDNA microarray of nestin in ampullary adenocarcinoma was compared with normal duodenum. CDK5 and Rac1 were assessed by western blotting. We hypothesized that nestin/CDK5/Rac1 signaling behaves different in early and advanced cancer. We found that the presence of nestin mRNA was increased in the early stages of cancer (T2N0 or T3N0) and advanced cancer with lymph node metastasis (T4N1). A total of 102 patients were enrolled in the IHC staining. Weak nestin expression was correlated with favorable characteristics of cancer, decreased incidence of local recurrence and lower risk of recurrence within 12 months after surgery. Patients with weak nestin expression had the most favorable recurrence?free survival rates. Patients with mild to strong nestin expression exhibited an advanced behavior of cancer and increased possibility of cancer recurrence. The reciprocal expression of nestin and RAC1 were explored using a cDNA microarray analysis in the early stages of ampullary adenocarcinoma. Increased level of CDK5 with simultaneously decreased expression of Rac1 was detected by western blotting of ampullary adenocarcinoma in patients without cancer recurrence. The activation of multiple oncogenic pathways, combined with the stemness characteristics of nestin, formed a complex network in advanced ampullary adenocarcinoma. Our study demonstrated that nestin performs a dual role in ampullary adenocarcinoma. Appropriate amount of nestin enhances CDK5 function to suppress Rac1 and excessive nestin/CDK5 participates in multiple oncogenic pathways to promote cancer invasiveness. Inhibiting nestin in patients who exhibit nestin?overexpressed ampullary adenocarcinoma may be a method of preventing cancer recurrence.
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Platinum-Free Counter Electrode Comprised of Metal-Organic-Framework (MOF)-Derived Cobalt Sulfide Nanoparticles for Efficient Dye-Sensitized Solar Cells (DSSCs).
Sci Rep
PUBLISHED: 08-13-2014
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We fabricated a highly efficient (with a solar-to-electricity conversion efficiency (?) of 8.1%) Pt-free dye-sensitized solar cell (DSSC). The counter electrode was made of cobalt sulfide (CoS) nanoparticles synthesized via surfactant-assisted preparation of a metal organic framework, ZIF-67, with controllable particle sizes (50 to 320?nm) and subsequent oxidation and sulfide conversion. In contrast to conventional Pt counter electrodes, the synthesized CoS nanoparticles exhibited higher external surface areas and roughness factors, as evidenced by X-ray diffraction (XRD), scanning electron microscopy (SEM) element mapping, and electrochemical analysis. Incident photon-to-current conversion efficiency (IPCE) results showed an increase in the open circuit voltage (VOC) and a decrease in the short-circuit photocurrent density (Jsc) for CoS-based DSSCs compared to Pt-based DSSCs, resulting in a similar power conversion efficiency. The CoS-based DSSC fabricated in the study show great potential for economically friendly production of Pt-free DSSCs.
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Increased expression of argininosuccinate synthetase protein predicts poor prognosis in human gastric cancer.
Oncol. Rep.
PUBLISHED: 08-06-2014
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Aberrant expression of argininosuccinate synthetase (ASS1, also known as ASS) has been found in cancer cells and is involved in the carcinogenesis of gastric cancer. The aim of the present study was to investigate the level of ASS expression in human gastric cancer and to determine the possible correlations between ASS expression and clinicopathological findings. Immunohistochemistry was performed on paraffin?embedded tissues to determine whether ASS was expressed in 11 of 11 specimens from patients with gastric cancer. The protein was localized primarily to the cytoplasm of cancer cells and normal epithelium. In the Oncomine cancer microarray database, expression of the ASS gene was significantly increased in gastric cancer tissues. To investigate the clinicopathological and prognostic roles of ASS expression, we performed western blot analysis of 35 matched specimens of gastric adenocarcinomas and normal tissue obtained from patients treated at the National Cheng Kung University Hospital. The ratio of relative ASS expression (expressed as the ASS/?-actin ratio) in tumor tissues to that in normal tissues was correlated with large tumor size (P=0.007) and with the tumor, node, metastasis (TNM) stage of the American Joint Committee on Cancer staging system (P=0.031). Patients whose cancer had increased the relative expression of ASS were positive for perineural invasion and had poor recurrence-free survival. In summary, ASS expression in gastric cancer was associated with a poor prognosis. Further study of mechanisms to silence the ASS gene or decrease the enzymatic activity of ASS protein has the potential to provide new treatments for patients with gastric cancer.
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Suppression of mucin 2 promotes interleukin-6 secretion and tumor growth in an orthotopic immune-competent colon cancer animal model.
Oncol. Rep.
PUBLISHED: 07-25-2014
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Mucin 2 (MUC2) is the major secreted mucin of the large intestine and is expressed by adenomas and mucinous carcinomas. Since colon cancer is associated with a proinflammatory microenvironment and dysregulated MUC2 expression, the aim of this study was to characterize the effects of MUC2 gene expression in colon tumor progression using colonic cancer cells. CT26 colon cancer cells were stably transfected with MUC2 siRNA (MUC2 RNAi) or a control construct containing a nonspecific sequence (scrambled RNAi). Expression of MUC2 was significantly decreased in the MUC2 RNAi cell clones. Although MUC2 suppression did not affect the cell growth of colon cancer cells in vitro, MUC2 knockdown promoted tumor growth in an orthotopic colon cancer model in vivo. MUC2 silencing also increased interleukin (IL)-6 secretion by colon cancer cells. IL-6 neutralization attenuated tumor formation by MUC2 RNAi cells; it also increased CD8 T cell infiltration into the peritoneum. Taken together, to the best of our knowledge, this is the first study indicating that the immune response to cancer cells plays an important role in tumor growth regulated by MUC2. Furthermore, given the effects of MUC2 on IL-6 secretion, its targeting may represent a potentially useful strategy to treat colonic carcinomas.
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Antimicrobial peptide GW-H1-induced apoptosis of human gastric cancer AGS cell line is enhanced by suppression of autophagy.
Mol. Cell. Biochem.
PUBLISHED: 07-15-2014
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Gastric cancer is one of the most common malignant cancers worldwide. Due to its poor prognosis and high mortality rate, development of an effective therapeutic method is of urgent need. It has been reported that antimicrobial peptides (AMPs), also known as host-defense peptides, can selectively bind to negatively charged prokaryotic and cancer cell membranes and exert cytotoxicity, without harming normal cells or causing severe drug resistance. We have designed a series of novel cationic AMPs with potent antimicrobial activity against a broad spectrum of bacterial pathogens. In the current study, we evaluated their anticancer potency toward gastric cancer AGS cell line. Cell viability assay revealed that GW-H1 exhibited the lowest IC50 value (less than 20 ?M). Flow cytometry showed that upon GW-H1 treatment for 0-24 h, apoptotic cell populations of AGS increased in a dose- and time-dependent manner. Western blot analysis further revealed that upon treatment for 2-6 h, apoptosis-related caspases-3, 7, 8, 9, and PARP were cleaved and activated, while autophagy-related LC3-II and beclin-1 were concomitantly increased. These results indicated that both apoptosis and autophagy were involved in the early stage of GW-H1-induced AGS cell death. However, upon treatment for 12-24 h, LC3-II began to decrease and cleaved beclin-1 increased in a time-dependent manner, suggesting that consecutive activation of caspases cleaved beclin-1 to inhibit autophagy, thus enhancing apoptosis at the final stage. These findings provided support for future application of GW-H1 as a potential anticancer agent for gastric cancer treatment.
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Acquisition of epithelial-mesenchymal transition and cancer stem-like phenotypes within chitosan-hyaluronan membrane-derived 3D tumor spheroids.
Biomaterials
PUBLISHED: 07-15-2014
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Cancer drug development has to go through rigorous testing and evaluation processes during pre-clinical in vitro studies. However, the conventional two-dimensional (2D) in vitro culture is often discounted by the insufficiency to present a more typical tumor microenvironment. The multicellular tumor spheroids have been a valuable model to provide more comprehensive assessment of tumor in response to therapeutic strategies. Here, we applied chitosan-hyaluronan (HA) membranes as a platform to promote three-dimensional (3D) tumor spheroid formation. The biological features of tumor spheroids of human non-small cell lung cancer (NSCLC) cells on chitosan-HA membranes were compared to those of 2D cultured cells in vitro. The cells in tumor spheroids cultured on chitosan-HA membranes showed higher levels of stem-like properties and epithelial-mesenchymal transition (EMT) markers, such as NANOG, SOX2, CD44, CD133, N-cadherin, and vimentin, than 2D cultured cells. Moreover, they exhibited enhanced invasive activities and multidrug resistance by the upregulation of MMP2, MMP9, BCRC5, BCL2, MDR1, and ABCG2 as compared with 2D cultured cells. The grafting densities of HA affected the tumor sphere size and mRNA levels of genes on the substrates. These evidences suggest that chitosan-HA membranes may offer a simple and valuable biomaterial platform for rapid generation of tumor spheroids in vitro as well as for further applications in cancer stem cell research and cancer drug screening.
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IL-23 promotes TCR-mediated negative selection of thymocytes through the upregulation of IL-23 receptor and ROR?t.
Nat Commun
PUBLISHED: 05-30-2014
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Transient thymic involution is frequently found during inflammation, yet the mode of action of inflammatory cytokines is not well defined. Here we report that interleukin-23 (IL-23) production by the thymic dendritic cells (DCs) promotes apoptosis of the CD4(hi)CD8(hi) double-positive (DP) thymocytes. A deficiency in IL-23 signalling interferes with negative selection in the male D(b)/H-Y T-cell receptor (TCR) transgenic mice. IL-23 plus TCR signalling results in significant upregulation of IL-23 receptor (IL-23R) expressed predominantly on CD4(hi)CD8(hi)CD3(+)??TCR(+) DP thymocytes, and leads to ROR?t-dependent apoptosis. These results extend the action of IL-23 beyond its peripheral effects to a unique role in TCR-mediated negative selection including elimination of natural T regulatory cells in the thymus.
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Increased risks of endotracheal tube cuff colonization after prolonged intubation.
Chin J Physiol
PUBLISHED: 05-16-2014
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Mechanical ventilation using endotracheal tube (ETT) intubation is crucial in saving life but may also cause ventilator-associated pneumonia resulting in morbidity and mortality. The purpose of this study was to examine the effects of intubation duration on pathogen colonization rates of ETT cuff region, and its association with the subsequent re-intubation and tracheostomy. We enrolled 92 patients who were successfully weaned from ventilator and were extubated within 20 days of intubation duration. Patients were divided into Group I and II based on intubation for 1-9 days and 10-20 days, respectively. Pathogen colonization over ETT cuff region and extra-cuff region (including sputum and ETT aspirates) were assessed. As compared to Group I patients, Group II patients had a significant higher pathogen colonization rate (100% vs. 69.2%; P < 0.001) in the ETT cuff samples, but not in the extracuff samples (92.6% vs. 84.8%; P = 0.442). Further studies demonstrated that there was no difference between Group I and II patients in the percentages of patients with the same pathogen over both the cuff and extra-cuff samples (35.5% vs. 30.8%; P = 0.925), suggesting that the increased pathogen colonization rate over the ETT cuff region was least likely from the extra-cuff region. In addition, the results showed that longer intubation was also associated with increased tracheostomy rate from 9.3% to 28.9% for Group I and Group II respectively (P = 0.025). We conclude that longer intubation has a higher pathogen colonization rate over the ETT cuff region in patients receiving mechanical ventilation support; longer intubation also increases the trend of receiving re-intubation and tracheostomy. Our findings indicate that it is crucial to remove ETT as soon as possible and perform pathogen culture over the ETT cuff regions immediately after extubation.
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Substrate-dependent modulation of 3D spheroid morphology self-assembled in mesenchymal stem cell-endothelial progenitor cell coculture.
Biomaterials
PUBLISHED: 05-06-2014
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The structural evolution of three-dimensional spheroids self-assembled from two different types of cells on selective biomaterials is demonstrated in this study. The two types of cells involved in the self-assembly are human mesenchymal stem cells (MSCs) and endothelial progenitor cells (EPCs). When seeded in different population ratios, they can create a variety of cellular patterns on different biomaterial substrates. When the two populations are matched in initial numbers, they are self-assembled in co-spheroids with different morphologies (i.e. randomly mixed, bumped, or concentric spheroids). The morphologies are influenced by the specific cell-substrate interaction possibly through integrin signaling, as well as a substrate-dependent regulation of heterophilic cell-cell interaction possibly through Notch signaling. In particular, the self-assembled core-shell concentric spheroids from adipose-derived MSCs and EPCs show a greater angiogenic effect in vitro. This study reveals the possibility to modulate the self-assembled morphology as well as the effect of cocultured cells by changing the cell culture substratum.
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A randomized controlled trial of clinic-based and home-based interventions in comparison with usual care for preterm infants: effects and mediators.
Res Dev Disabil
PUBLISHED: 04-29-2014
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This study examined the effects and mediators of a clinic-based intervention program (CBIP) and a home-based intervention program (HBIP) compared with usual care in very-low-birth-weight (VLBW) preterm infants on developmental and behavioral outcomes at 24 months of age (corrected for prematurity). In this randomized controlled trial, VLBW preterm infants received either CBIP (n=57), HBIP (n=63), or usual care (n=58) from hospitalization to 12 months. At 12 months, infant emotional regulation was assessed using the toy-behind-barrier procedure and dyadic interaction was observed during free play. At 24 months, infant developmental and behavioral outcomes were assessed using the Bayley Scales of Infant and Toddler Development- 3rd edition and the Child Behavior Checklist for Ages 1.5-5, respectively. Compared with infants under usual care, the CBIP-group infants showed higher cognitive composite scores (difference, 95% confidence interval (CI)=4.4, 0.8-7.9) and a lower rate of motor delay (odds ratio (OR), 95% CI=0.29, 0.08-0.99); the HBIP-group infants had lower sleep problem scores (difference, 95% CI=-1.4, -2.5 to -0.3) and a lower rate of internalizing problems at 24 months (OR, 95% CI=0.51, 0.28-0.93) (all p<.05). The CBIP's effect on cognitive outcome was attenuated when maternal or dyadic interactive behavior was considered; whereas the HBIP's effect on sleep and internalizing behavior was attenuated when duration of orientation to a toy or object was considered. In conclusions, interventions enhanced the cognitive, motor, and behavioral outcomes of VLBW preterm infants. The effects on cognitive and behavioral outcomes might be mediated by early-improved mother-infant interaction and infant emotional regulation, respectively.
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CT of globe rupture: analysis and frequency of findings.
AJR Am J Roentgenol
PUBLISHED: 04-25-2014
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The objective of our study was to evaluate the CT characteristics of globe rupture.
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Efficient gene silencing in mesenchymal stem cells by substrate-mediated RNA interference.
Tissue Eng Part C Methods
PUBLISHED: 04-22-2014
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We described a novel substrate-mediated RNA interference (RNAi) technology to investigate the effect of neural crest marker expression on the multipotency of human gingival fibroblasts (HGFs). HGFs showed significantly higher neural and chondrogenic differentiation potentials compared with adult bone-marrow-derived mesenchymal stem cells and stem cells from human exfoliated deciduous teeth. By sending target-specific RNAi agents with the conventional vehicle (PolyFect), we observed that the multipotency of HGFs was closely associated with the expression of neural crest marker gene Forkhead box D3 (FoxD3). Using the novel chitosan substrate-mediated method, we successfully delivered short-hairpin RNA constructs to HGFs grown on chitosan without the use of conventional vehicles. The delivery efficiency measured by flow cytometry showed a 10-fold increase for HGFs on chitosan versus those on culture dish, and the cell viability was >95%. Moreover, HGFs with FoxD3 gene knockdown did not form spheroids on chitosan. Based on this working principle, we further selected the gene-silenced population from HGFs. The nonsilenced HGFs showed much higher neural differentiation ability with the nestin expression 40-fold greater than FoxD3-silenced population after induction, suggesting the feasibility of the method to silence genes. The new substrate-mediated gene silencing platform that combines the use of substrate and RNAi can be used to clarify the functions of important genes without suffering the toxicity.
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Trajectories of Physical Activity and Risk Factors Among Taiwanese Older Adults.
Int J Behav Med
PUBLISHED: 04-05-2014
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The significance of physical activity has been noticed. However, the dynamic change and the heterogeneity of physical activity patterns among older people are little explored.
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Regulation of human endothelial progenitor cell maturation by polyurethane nanocomposites.
Biomaterials
PUBLISHED: 04-04-2014
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The mobilization and homing of endothelial progenitor cells (EPCs) are critical to the development of an antithrombotic cardiovascular prosthesis. Polyurethane (PU) with superior elasticity may provide a mechanical environment resembling that of the natural vascular tissues. The topographical cues of PU were maximized by making nanocomposites with a small amount of gold nanoparticles (AuNPs). The nanocomposites of PU-AuNPs ("PU-Au") with a favorable response of endothelial cells were previously established. In the current study, the effect of PU and PU-Au nanocomposites on the behavior of human peripheral blood EPCs was investigated in vitro and in vivo. It was found that PU-Au promoted EPCs to become differentiated endothelial cells in vitro, confirmed by the increased expressions of CD31 and VEGF-R2 surface markers. The increased maturation of EPCs was significantly more remarkable on PU-Au, probably through the stromal derived factor 1? (SDF-1?)/CXCR4 signaling pathway. In vivo experiments showed that EPCs seeded on PU-Au coated catheters effectively reduced thrombosis by differentiation into endothelial cells. Surface endothelialization with CD31 and CD34 expression as well as intimal formation with ?-SMA expression was significantly accelerated in the group receiving EPC-seeded PU-Au catheters. Moreover, the analysis of collagen deposition revealed a reduction of fibrosis in the group receiving EPC-seeded PU-Au catheters as compared to the other groups. These results suggest that EPCs engineered with a proper elastic substrate may provide unique endothelialization and antithrombogenic properties that benefit vascular tissue regeneration.
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Characterization of biodegradable polyurethane nanoparticles and thermally induced self-assembly in water dispersion.
ACS Appl Mater Interfaces
PUBLISHED: 04-01-2014
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Waterborne polyurethanes (PU) with different compositions of biodegradable oligodiols as the soft segment were synthesized as nanoparticles (NPs) in this study. Using dynamic light scattering (DLS), multiangle light scattering (MALS), transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS), we demonstrated that these NPs were compact spheres with different shape factors. The temperature-dependent swelling of the PU NPs in water was distinct. In particular, PU NPs with 80 mol % polycaprolactone (PCL) diol and 20 mol % poly(L-lactide) (PLLA) diol as the soft segment had significant swelling (?450%) at 37 °C. This was accompanied by a sol-gel transition observed in about 2 min for the NP dispersion. The thermally induced swelling and self-assembly of these NPs were associated with the secondary force (mainly hydrogen bonding) and degree of crystallinity, which depended on the soft segment compositions. The thermo-responsiveness of the PU NPs with mixed biodegradable oligodiols may be employed to design smart biodegradable carriers for delivery of cells or drugs near body temperature.
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Combined mutational analysis of RAS, BRAF, PIK3CA, and TP53 genes in Taiwanese patients with oral squamous cell carcinoma.
Oral Surg Oral Med Oral Pathol Oral Radiol
PUBLISHED: 03-13-2014
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Many genetic factors have been implicated in the development of oral squamous cell carcinoma (OSCC). Although mutations associated with OSCC have been well documented, the rate of these mutations is known to vary by location. The goal of this study was to determine the frequency of RAS, BRAF, PIK3CA, and TP53 mutations in OSCC within the Taiwanese population.
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The effect of elastic biodegradable polyurethane electrospun nanofibers on the differentiation of mesenchymal stem cells.
Colloids Surf B Biointerfaces
PUBLISHED: 03-10-2014
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Biodegradable polyurethane (PU) was synthesized based on using poly(?-caprolactone) (PCL) as the soft segment. Fibers in different diameters (200-400nm, 600-800nm, and 1.4-1.6?m) were then made by electrospinning PU solution in N,N-dimethylacetamide and 2,2,2-trifluoroethanol. Human bone marrow derived mesenchymal stem cells (hMSCs) in the form of single dispersed cells or aggregates were seeded on the electrospun meshes for evaluation of cell behavior. Differentiation experiments showed that hMSC aggregates on electrospun fibers had greater differentiation capacities than single cells. Besides, nanofibers of 200-400nm diameters significantly promoted the osteogenic and chondrogenic differentiation of hMSCs than fibers of the other diameters. The effect of substrate elasticity was further elucidated by comparing cell behaviors on the nanofibers of PCL-based PU and those of pure PCL. The more elastic PU nanofibers demonstrated more osteogenic and chondrogenic induction potential than PCL electrospun fibers. We suggested that the elastic nanofibers seeded with hMSC aggregates may be advantageous for cartilage and bone tissue engineering.
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High cytoplasmic expression of Krüppel-like factor 4 is an independent prognostic factor of better survival in hepatocellular carcinoma.
Int J Mol Sci
PUBLISHED: 03-06-2014
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Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related mortality in the world. Hepatocarcinogenesis is complex, with an extraordinary molecular heterogeneity. Krüppel-like factor 4 (KLF4) plays an important role in cell proliferation and differentiation, and it can function as a tumor suppressor or an oncoprotein, depending on tissue type. The role of KLF4 in HCC remains controversial. The aim of this study was to explore the clinical significance of KLF4 expression in HCC. The study included 205 patients with surgical resection. We performed immunostaining for KLF4 and Ki-67 to investigate the correlations of the clinicopathological parameters of HCC and to examine the proliferative index. KLF4 staining was observed in the cytoplasm of non-tumorous hepatocytes and tumor cells. We subdivided the immunohistological staining results for KLF4 into low expression (Staining 0 and 1+) and high expression (Staining 2+ and 3+) subgroups. The expression of KLF4 was significantly correlated with tumor differentiation (p = 0.001). The Ki-67 proliferative index was significantly lower in well-differentiated HCCs (0.781% ± 1.02% vs. 2.16% ± 3.14%, p = 0.012), but not significantly different between low-KLF4 expression and high-KLF4 expression (1.87% ± 2.93% vs. 2.51% ± 3.28%, p = 0.32). Kaplan-Meier analysis showed that a high expression of KLF4 was significantly correlated with a longer disease-specific survival (p = 0.019). Univariate and multivariate analyses showed that high KLF4 expression was an independent predictor of a better disease-specific survival (p = 0.017; hazard ratio = 0.398; 95% confidence interval: 0.19-0.85). High cytoplasmic expression of KLF4 was associated with better disease-specific survival and was an independently favorable prognostic factor in hepatocellular carcinoma. These promising results suggest that KLF4 may play an anti-oncogenic role in hepatocarcinogenesis.
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Structural and functional analyses of a glutaminyl cyclase from Ixodes scapularis reveal metal-independent catalysis and inhibitor binding.
Acta Crystallogr. D Biol. Crystallogr.
PUBLISHED: 02-22-2014
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Glutaminyl cyclases (QCs) from mammals and Drosophila are zinc-dependent enzymes that catalyze N-terminal pyroglutamate formation of numerous proteins and peptides. These enzymes have been found to be critical for the oviposition and embryogenesis of ticks, implying that they are possible physiological targets for tick control. Here, 1.10-1.15?Å resolution structures of a metal-independent QC from the black-legged tick Ixodes scapularis (Is-QC) are reported. The structures exhibit the typical scaffold of mammalian QCs but have two extra disulfide bridges that stabilize the central ?-sheet, resulting in an increased thermal stability. Is-QC contains ~0.5 stoichiometric zinc ions, which could be removed by 1?mM EDTA. Compared with the Zn-bound form, apo-Is-QC has a nearly identical active-site structure and stability, but unexpectedly possesses significantly increased QC activities towards both synthetic and physiological substrates. Enzyme-kinetic analysis revealed that apo-Is-QC has a stronger substrate-binding affinity, suggesting that bound zinc interferes with substrate binding during catalysis. The structures of Is-QC bound to the inhibitor PBD150 revealed similar binding modes to both forms of Is-QC, with the exception of the inhibitor imidazole ring, which is consistent with the comparable inhibition activities of the inhibitor towards both forms of Is-QC. These findings have implications for the design of new QC inhibitors.
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Fatty acid metabolic enzyme acyl-CoA thioesterase 8 promotes the development of hepatocellular carcinoma.
Oncol. Rep.
PUBLISHED: 02-07-2014
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Dysregulated metabolism is an emerging hallmark of cancer development, and upregulated lipid synthesis is one of the important tumor metabolic features. However, lipolysis may also contribute to cancer pathogenesis by altering free fatty acid (FFA) metabolism. In the present study, we investigated the importance of the lipolytic enzyme acyl-CoA thioesterase 8 (ACOT8) in hepatocellular carcinoma (HCC) development. Bioinformatic analysis of published microarrays regarding clinical specimens revealed that both ACOT8 gene copy number and mRNA expression were increased in HCC tissues when compared to these variables in non-tumor tissues. ACOT8 silencing with specific shRNA stably expressed in Huh7 and Hep3B HCC cell lines showed that ACOT8 protein expression and overall thioesterase activity were reduced following ACOT8 knockdown. In vitro tumorigenic assays revealed that ACOT8 knockdown inhibited anchorage-dependent and ?independent growth of HCC cell lines. This growth inhibition was partially rescued by addition of the FFA, myristic acid, indicating the importance of FFA in cancer metabolism. In summary, lipolytic enzyme ACOT8 is frequently upregulated in HCC clinical specimens. More importantly, ACOT8 silencing leads to inhibition of cell growth in HCC in vitro.
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Inhibition of fucosylation reshapes inflammatory macrophages and suppresses type II collagen-induced arthritis.
PUBLISHED: 02-03-2014
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Fucosylation catalyzed by fucosyltransferases (FUTs) is an important posttranslational modification involved in a variety of biologic processes. This study was undertaken to determine the roles of fucosylation in rheumatoid arthritis (RA) and to assess the efficacy of reestablishing immune homeostasis with the use of 2-deoxy-d-galactose (2-d-gal), a fucosylation inhibitor.
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Large-scale synthesis of reduced graphene oxides with uniformly coated polyaniline for supercapacitor applications.
ChemSusChem
PUBLISHED: 01-29-2014
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We report an effective route for the preparation of layered reduced graphene oxide (rGO) with uniformly coated polyaniline (PANI) layers. These nanocomposites are synthesized by chemical oxidative polymerization of aniline monomer in the presence of layered rGO. SEM, TEM, X-ray photoelectron spectroscopy (XPS), FTIR, and Raman spectroscopy analysis results demonstrated that reduced graphene oxide-polyaniline (rGO-PANI) nanocomposites are successfully synthesized. Because of synergistic effects, rGO-PANI nanocomposites prepared by this approach exhibit excellent capacitive performance with a high specific capacitance of 286?F?g(-1) and high cycle reversibility of 94?% after 2000?cycles.
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Surfactant-modified nanoclay exhibits an antiviral activity with high potency and broad spectrum.
J. Virol.
PUBLISHED: 01-29-2014
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Nanomaterials have the characteristics associated with high surface-to-volume ratios and have been explored for their antiviral activity. Despite some success, cytotoxicity has been an issue in nanomaterial-based antiviral strategies. We previously developed a novel method to fully exfoliate montmorillonite clay to generate the most fundamental units of nanoscale silicate platelet (NSP). We further modified NSP by capping with various surfactants and found that the surfactant-modified NSP (NSQ) was less cytotoxic. In this study, we tested the antiviral potentials of a series of natural-clay-derived nanomaterials. Among the derivatives, NSP modified with anionic sodium dodecyl sulfate (NSQc), but not the pristine clay, unmodified NSP, a silver nanoparticle-NSP hybrid, NSP modified with cationic n-octadecanylamine hydrochloride salt, or NSP modified with nonionic Triton X-100, significantly suppressed the plaque-forming ability of Japanese encephalitis virus (JEV) at noncytotoxic concentrations. NSQc also blocked infection with dengue virus (DEN) and influenza A virus. Regarding the antiviral mechanism, NSQc interfered with viral binding through electrostatic interaction, since its antiviral activity can be neutralized by Polybrene, a cationic polymer. Furthermore, NSQc reduced the lethality of JEV and DEN infection in mouse challenge models. Thus, the surfactant-modified exfoliated nanoclay NSQc may be a novel nanomaterial with broad and potent antiviral activity.
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Role of VEGF-C gene polymorphisms in susceptibility to hepatocellular carcinoma and its pathological development.
J. Clin. Lab. Anal.
PUBLISHED: 01-29-2014
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Vascular endothelial growth factor C (VEGF-C), an angiogenic/lymphangiogenic factor with high expression levels in tumor tissues, plays important roles in the development of several malignancies including hepatocellular carcinoma (HCC). The purpose of this study was to examine whether VEGF-C gene polymorphisms are associated with susceptibility to HCC and its clinicopathological development.
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Neocartilage formation from mesenchymal stem cells grown in type II collagen-hyaluronan composite scaffolds.
Differentiation
PUBLISHED: 01-24-2014
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Three-dimensional (3D) collagen type II-hyaluronan (HA) composite scaffolds (CII-HA) which mimics the extracellular environment of natural cartilage were fabricated in this study. Rheological measurements demonstrated that the incorporation of HA increased the compression modulus of the scaffolds. An initial in vitro evaluation showed that scaffolds seeded with porcine chondrocytes formed cartilaginous-like tissue after 8 weeks, and HA functioned to promote the growth of chondrocytes into scaffolds. Placenta-derived multipotent cells (PDMC) and gingival fibroblasts (GF) were seeded on tissue culture polystyrene (TCPS), CII-HA films, and small intestinal submucosa (SIS) sheets for comparing their chondrogenesis differentiation potentials with those of adipose-derived adult stem cells (ADAS) and bone marrow-derived mesenchymal stem cells (BMSC). Among different cells, PDMC showed the greatest chondrogenic differentiation potential on both CII-HA films and SIS sheets upon TGF-?3 induction, followed by GF. This was evidenced by the up-regulation of chondrogenic genes (Sox9, aggrecan, and collagen type II), which was not observed for cells grown on TCPS. This finding suggested the essential role of substrate materials in the chondrogenic differentiation of PDMC and GF. Neocartilage formation was more obvious in both PDMC and GF cells plated on CII-HA composite scaffolds vs. 8-layer SIS at 28 days in vitro. Finally, implantation of PDMC/CII-HA constructs into NOD-SCID mice confirmed the formation of tissue-engineered cartilage in vivo.
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Role of CX3CL1 in the chemotactic migration of all-trans retinoic acid-treated acute promyelocytic leukemic cells toward apoptotic cells.
J Chin Med Assoc
PUBLISHED: 01-15-2014
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Phagocytic clearance of apoptotic neutrophils by tissue macrophages is a crucial component in the resolution phase of acute inflammation. However, the number of tissue macrophages is low and not likely to cope satisfactorily with the excess number of dying neutrophils. Although recent studies have reported that neutrophils are able to engulf apoptotic neutrophils, the mechanisms by which living neutrophils are attracted to apoptotic neutrophils are poorly defined. Increased amounts of CX3CL1 and microparticles (MPs) are rapidly released by apoptotic cells, and are involved in the chemoattraction of mononuclear phagocytes toward apoptotic cells. The current study investigated the role of CX3CL1 in the chemoattraction of all-trans retinoic acid (ATRA)-treated NB4 (ATRA-NB4) cells toward apoptotic cells.
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Development and application of a monoclonal antibody against grouper iridovirus (GIV) major capsid protein.
J. Virol. Methods
PUBLISHED: 01-09-2014
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The major capsid protein (MCP) is a main structural protein of iridoviruses, and is used as a marker for the identification, differentiation and classification of ranaviruses. In the present study, six monoclonal antibodies (mAbs) against recombinant MCP of grouper iridovirus (GIV) were produced and characterized. All of the six mAbs were of IgG1 isotype. Among the mAbs, GIV-MCP-mAb-21 showed the highest reactivity in ELISA and was used to further characterize the expression of GIV-MCP during viral replication. RT-PCR and Western blot analyses revealed that GIV-MCP is a late gene during GIV infection. By immunofluorescence assay, the presence of GIV-MCP was observed in not only the cytoplasm but also the nucleus of GIV-infected cells, a surprising finding that might indicate additional role of GIV-MCP. In conclusion, the newly established GIV-MCP-mAbs are a valuable tool for GIV diagnostic and future studies on GIV pathogenesis.
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Synthesis and 3D Printing of Biodegradable Polyurethane Elastomer by a Water-Based Process for Cartilage Tissue Engineering Applications.
Adv Healthc Mater
PUBLISHED: 01-09-2014
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Biodegradable materials that can undergo degradation in vivo are commonly employed to manufacture tissue engineering scaffolds, by techniques including the customized 3D printing. Traditional 3D printing methods involve the use of heat, toxic organic solvents, or toxic photoinitiators for fabrication of synthetic scaffolds. So far, there is no investigation on water-based 3D printing for synthetic materials. In this study, the water dispersion of elastic and biodegradable polyurethane (PU) nanoparticles is synthesized, which is further employed to fabricate scaffolds by 3D printing using polyethylene oxide (PEO) as a viscosity enhancer. The surface morphology, degradation rate, and mechanical properties of the water-based 3D-printed PU scaffolds are evaluated and compared with those of polylactic-co-glycolic acid (PLGA) scaffolds made from the solution in organic solvent. These scaffolds are seeded with chondrocytes for evaluation of their potential as cartilage scaffolds. Chondrocytes in 3D-printed PU scaffolds have excellent seeding efficiency, proliferation, and matrix production. Since PU is a category of versatile materials, the aqueous 3D printing process developed in this study is a platform technology that can be used to fabricate devices for biomedical applications.
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Interleukin-21 promotes germinal center reaction by skewing the follicular regulatory T cell to follicular helper T cell balance in autoimmune BXD2 mice.
PUBLISHED: 01-06-2014
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Follicular regulatory T (Tfr) cells act as the regulatory counterpart of follicular helper T (Tfh) cells to suppress germinal center (GC) B cell differentiation. We recently showed that interleukin-21 (IL-21) promoted Tfh cell differentiation in autoimmune BXD2 mice that develop spontaneous GCs. This study was undertaken to determine the modulatory effects of IL-21 on Tfr cells and the Tfr cell to Tfh cell balance in BXD2 mice.
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Substrate-dependent gene regulation of self-assembled human MSC spheroids on chitosan membranes.
BMC Genomics
PUBLISHED: 01-05-2014
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Three-dimensional (3D) multicellular spheroids of mesenchymal stem cells (MSCs) are generally regarded to have beneficial properties over MSCs in monolayer. Recent literatures have documented that MSCs can self-assemble into 3D spheroids with a greater capacity for differentiation into various cell types when grown on chitosan (CS), a biopolymer. The genomic modulation occurring in these MSC spheroids is thus of essential importance for understanding their uniqueness and therapeutic potentials. In this study, 3D spheroids self-assembled from human umbilical cord MSCs grown on CS membranes were analyzed by mRNA as well as microRNA microarrays, which helped identify the critical signaling events that may alter the cellular functions during the spheroid forming process.
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Substrate-mediated nanoparticle/gene delivery to MSC spheroids and their applications in peripheral nerve regeneration.
Biomaterials
PUBLISHED: 01-02-2014
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Substrate-derived mesenchymal stem cell (MSC) spheroids show greater differentiation capacities than dispersed single cells in vitro. During spheroid formation, nanoparticles (NPs)/genes may be delivered into the cells. In this study, MSCs were conveniently labeled with superparamagnetic Fe3O4 NPs, or transfected with brain-derived neurotrophic factor (BDNF) gene, by the substrate-mediated NP/gene uptake. With the promising in vitro data showing the beneficial effect on neural development and neurotrophic factor expression, MSCs were combined with a polymeric nerve conduit to bridge a 10 mm transection gap of rat sciatic nerve. High-resolution (7-T) magnetic resonance imaging (MRI) was used to track the transplanted cells. Nerve regeneration was assessed by functional recovery and histology. Results revealed that Fe3O4 NP-labeled MSCs were successfully visualized by MRI in vivo. Animals receiving BDNF-transfected MSC spheroids demonstrated the shortest gap bridging time (<21 days), the largest regenerated nerve, and the thickest myelin sheath at 31 days. Compared to MSC single cells, the pristine or BDNF-transfected MSC spheroids significantly promoted the functional recovery of animals, especially for the BDNF-transfected MSC spheroids. The transplanted MSCs were incorporated in the regenerated nerve and differentiated into non-myelinating Schwann cells after 31 days. This study suggests that the substrate-mediated gene delivery and NP labeling may provide extra values for MSC spheroids to carry therapeutic/diagnostic agents in cell-based therapy.
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Isolated panniculitis with vasculitis of the male breast suspicious for malignancy on CT and ultrasound: a case report and literature review.
Springerplus
PUBLISHED: 01-01-2014
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We report a case of a 54-year-old male patient with a hard, painful nodule within his right breast which was misdiagnosed preoperatively as breast cancer.
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Erythrocytic mobilization enhanced by the granulocyte colony-stimulating factor is associated with reduced anthrax-lethal-toxin-induced mortality in mice.
PLoS ONE
PUBLISHED: 01-01-2014
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Anthrax lethal toxin (LT), one of the primary virulence factors of Bacillus anthracis, causes anthrax-like symptoms and death in animals. Experiments have indicated that levels of erythrocytopenia and hypoxic stress are associated with disease severity after administering LT. In this study, the granulocyte colony-stimulating factor (G-CSF) was used as a therapeutic agent to ameliorate anthrax-LT- and spore-induced mortality in C57BL/6J mice. We demonstrated that G-CSF promoted the mobilization of mature erythrocytes to peripheral blood, resulting in a significantly faster recovery from erythrocytopenia. In addition, combined treatment using G-CSF and erythropoietin tended to ameliorate B. anthracis-spore-elicited mortality in mice. Although specific treatments against LT-mediated pathogenesis remain elusive, these results may be useful in developing feasible strategies to treat anthrax.
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Dysregulated cytokine production by dendritic cells modulates B cell responses in the NZM2410 mouse model of lupus.
PLoS ONE
PUBLISHED: 01-01-2014
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The breakdown in tolerance of autoreactive B cells in the lupus-prone NZM2410-derived B6.Sle1.Sle2.Sle3 (TC) mice results in the secretion of autoantibodies. TC dendritic cells (DCs) enhance B cell proliferation and antibody secretion in a cytokine-dependent manner. However, the specific cytokine milieu by which TC DCs activate B cells was not known. In this study, we compared TC and C57BL/6 (B6) control for the distribution of DC subsets and for their production of cytokines affecting B cell responses. We show that TC DCs enhanced B cell proliferation through the production of IL-6 and IFN-?, while antibody secretion was only dependent on IL-6. Pre-disease TC mice showed an expanded PDCA1(+) cells prior to disease onset that was localized to the marginal zone and further expanded with age. The presence of PDCA1(+) cells in the marginal zone correlated with a Type I Interferon (IFN) signature in marginal zone B cells, and this response was higher in TC than B6 mice. In vivo administration of anti-chromatin immune complexes upregulated IL-6 and IFN-? production by splenic DCs from TC but not B6 mice. The production of BAFF and APRIL was decreased upon TC DC stimulation both in vitro and in vivo, indicating that these B cell survival factors do not play a role in B cell modulation by TC DCs. Finally, TC B cells were defective at downregulating IL-6 expression in response to anti-inflammatory apoptotic cell exposure. Overall, these results show that the TC autoimmune genetic background induces the production of B cell-modulating inflammatory cytokines by DCs, which are regulated by the microenvironment as well as the interplay between DC.
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In vitro study of a novel nanogold-collagen composite to enhance the mesenchymal stem cell behavior for vascular regeneration.
PLoS ONE
PUBLISHED: 01-01-2014
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Novel nanocomposites based on type I collagen (Col) containing a small amount (17.4, 43.5, and 174 ppm) of gold nanoparticles (AuNPs, approximately 5 nm) were prepared in this study. The pure Col and Col-AuNP composites (Col-Au) were characterized by the UV-Vis spectroscopy (UV-Vis), surface-enhanced raman spectroscopy (SERS) and atomic force microscopy (AFM). The interaction between Col and AuNPs was confirmed by infrared (IR) spectra. The effect of AuNPs on the biocompatibility of Col, evaluated by the proliferation and reactive oxygen species (ROS) production of mesenchymal stem cells (MSCs) as well as the activation of monocytes and platelets, was investigated. Results showed that Col-Au had better biocompatibility than Col. Upon stimulation by vascular endothelial growth factor (VEGF) and stromal derived factor-1? (SDF-1?), MSCs expressed the highest levels of ?v?3 integrin/CXCR4, focal adhesion kinase (FAK), matrix metalloproteinase-2 (MMP-2), and Akt/endothelial nitric oxide synthase (eNOS) proteins when grown on the Col-Au (43.5 ppm) nanocomposite. Taken together, Col-Au nanocomposites may promote the proliferation and migration of MSCs and stimulate the endothelial cell differentiation. These results suggest that Col-Au may be used to construct tissue engineering scaffolds for vascular regeneration.
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Synthesis of water-dispersible zinc oxide quantum dots with antibacterial activity and low cytotoxicity for cell labeling.
Nanotechnology
PUBLISHED: 10-31-2013
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Typical photoluminescent semiconductor nanoparticles, called quantum dots (QDs), have potential applications in biological labeling. When used to label stem cells, QDs may impair the differentiation capacity of the stem cells. In this study, we synthesized zinc oxide (ZnO) QDs in methanol with an average size of ?2 nm. We then employed two different types of polyethylene glycol (PEG) molecules (SH-PEG-NH2 and NH2-PEG-NH2) to conjugate ZnO QDs and made them water-dispersible. Fourier transform infrared spectroscopy spectra indicated the attachment of PEG molecules on ZnO QDs. No obvious size alteration was observed for ZnO QDs after PEG conjugation. The water-dispersible ZnO QDs still retained the antibacterial activity and fluorescence intensity. The cytotoxicity evaluation revealed that ZnO QDs at higher concentrations decreased cell viability but were generally safe at 30 ppm or below. Cell lines of hepatocytes (HepG2), osteoblasts (MC3T3-E1) and mesenchymal stem cells (MSCs) were successfully labeled by the water-dispersible ZnO QDs at 30 ppm. The ZnO QD-labeled MSCs maintained their stemness and differentiation capacity. Therefore, we conclude that the water-dispersible ZnO QDs developed in this study have antibacterial activity, low cytotoxicity, and proper labeling efficiency, and can be used to label a variety of cells including stem cells.
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Nanohybrids of silver particles on clay platelets delaminate Pseudomonas biofilms.
Nanomedicine (Lond)
PUBLISHED: 09-11-2013
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Aim: To evaluate the effectiveness of novel nanohybrids, composed of silver nanoparticles and nanoscale silicate platelets, to clear Pseudomonas aeruginosa biofilms. Materials & methods: The nanohybrids were manufactured from an in situ reduction of silver salts in the silicate platelet dispersion, and then applied to biofilms in vitro and in vivo. Results: In reference to the biocidal effects of gentamycin, the nanohybrids mitigated the spreading of the biofilms, and initiated robust cell death and exfoliation from the superficial layers of the biofilms in vitro. In vivo, the nanohybrids exhibited significant therapeutic effects by eliminating established biofilms from infected corneas and promoting the recovery of corneal integrity. Conclusion: All of the evaluations indicate the high potency of the newly developed silver nanoparticle/nanoscale silicate platelet nanohybrids for eliminating biofilms. Original submitted 6 June 2012; revised submitted 13 February 2013.
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Cell orientation and regulation of cell-cell communication in human mesenchymal stem cells on different patterns of electrospun fibers.
Biomed Mater
PUBLISHED: 09-03-2013
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Cell behavior can be manipulated by the topography of the culture surface. In this study, we examined the intercellular communication and osteogenic differentiation of mesenchymal stem cells (MSCs) grown on electrospun fibers with different orientations and densities. Human bone marrow-derived MSCs (hMSCs) were seeded on poly(?-caprolactone) (PCL) electrospun scaffolds composed of aligned (1D) or cross-aligned (2D) fibers (1.0-1.2 µm diameter) with high, medium, or low fiber densities. It was found that cells preferred to adhere onto electrospun PCL fibers rather than on the flat substrate. The immunofluorescence staining showed that the expression of vinculin, a focal adhesion protein, was limited to the periphery and the two extremities of aligned cells on the edge of the fibers. Electron microscopy showed that cells extended their lamellipodia across the adjacent fibers and proliferated along the direction of fibers. Cells grown on 1D fibrous scaffolds at all fiber densities had an obvious alignment. On 2D fibers, a higher degree of cell alignment was observed at the higher fiber density. On 1D scaffolds, the gap junction intercellular communication (GJIC) quantified by the lucifer yellow dye transfer assay was significantly promoted in the aligned cells in the direction parallel to the fibers but was abolished in the direction perpendicular to the fibers. The expression of osteogenic marker genes (RUNX2, ALP, and OCN) was significantly enhanced in seven days by culture on 1D but not 2D fibers. It was thus proposed that the promoted osteogenic differentiation of hMSCs may be associated with the fiber-guided and directional induction of GJIC.
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Attenuation of argininosuccinate lyase inhibits cancer growth via cyclin A2 and nitric oxide.
Mol. Cancer Ther.
PUBLISHED: 08-26-2013
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Arginine biosynthesis and nitric oxide (NO) production are important for cancer homeostasis. Degradation of arginine may be used to inhibit liver tumors with low argininosuccinate synthetase (ASS) expression. In this report, we investigated an alternative therapeutic approach by targeting argininosuccinate lyase (ASL). ASL is transcriptionally induced by endoplasmic reticulum stress and is overexpressed in some human liver tumors. Knockdown of ASL expression by short hairpin RNA (shRNA) in three liver cancer cell lines, ML-1, HuH-7, and HepG2, decreased colony formation in vitro and tumor growth in vivo. Furthermore, lentiviral infection of ASL shRNA inhibited tumor growth in a therapeutic animal tumor model. Analysis of ASL shRNA on the cell-cycle progression revealed a G2-M delay. Among cell-cycle regulatory molecules, cyclin A2 expression was reduced. Reintroduction of exogenous cyclin A2 restored the cell growth in ASL-knockdown cells. Autophagy was observed in the cells treated with ASL shRNA, as shown by an increase in LC3-II levels and autophagosome formation. The total cellular arginine level was not altered significantly. Inhibition of autophagy further attenuated cell growth, suggesting that autophagy induced by ASL shRNA plays a feedback prosurvival function. Knockdown of ASL reduced NO content, and addition of NO donor partially recovered the growth inhibition by ASL shRNA. In summary, downregulation of ASL attenuated tumor growth and the inhibition was mainly mediated by a decrease of cyclin A2 and NO.
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Field assessment of Orientia tsutsugamushi infection in small mammals and its association with the occurrence of human scrub typhus in Taiwan.
Acta Trop.
PUBLISHED: 08-13-2013
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We conducted an extensive study in Taiwan of Orientia tsutsugamushi (OT) infection in small wild mammals. Field trapping was carried out at six districts in eastern and western Taiwan as well as various offshore islands during the period 2006-2010. A total of 1061 specimens representing 11 rodent species were captured. The presence of OT infection was assessed by indirect immunofluorescence assay and polymerase chain reaction assays of 56-kDa type-specific antigen gene. The chigger infestation rate among the animals was 35% (371/1061). Among these, OT was detected in 64% (238/371) of the chiggers from the infested animals and in the spleens from 273 (34.3%) of 797 animals. Excluding animals in the Suncus murinus group, the antibody positive rate of scrub typhus was 69.1% (477 of 690 of serum samples). The prevalence of OT infection in animals from areas with a low incidence of human cases of scrub typhus was significantly lower than that in rodents obtained from regions with a high incidence of human cases of the disease (44.4%±4.0% vs. 71.2%±9.7%, p<0.001). In Taiwan, the prevalence of OT infection in wild rodents is considerably high and appears to correlate positively with the occurrence of scrub typhus in humans.
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Fabrication of bioactive conduits containing the fibroblast growth factor 1 and neural stem cells for peripheral nerve regeneration across a 15 mm critical gap.
Biofabrication
PUBLISHED: 07-23-2013
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Nerve conduits are often used in combination with bioactive molecules and stem cells to enhance peripheral nerve regeneration. In this study, the acidic fibroblast growth factor 1 (FGF1) was immobilized onto the microporous/micropatterned poly (D, L-lactic acid) (PLA) nerve conduits after open air plasma treatment. PLA substrates grafted with chitosan in the presence of a small amount of gold nanoparticles (nano Au) showed a protective effect on the activity of the immobilized FGF1 in vitro. Different conduits were tested for their ability to bridge a 15 mm critical gap defect in a rat sciatic nerve injury model. Axon regeneration and functional recovery were evaluated by histology, walking track analysis and electrophysiology. Among different conduits, PLA conduits grafted with chitosan-nano Au and the FGF1 after plasma activation had the greatest regeneration capacity and functional recovery in the experimental animals. When the above conduit was seeded with aligned neural stem cells, the efficacy was further enhanced and it approached that of the autograft group. This work suggested that microporous/micropatterned nerve conduits containing bioactive growth factors may be successfully fabricated by micropatterning techniques, open plasma activation, and immobilization, which, combined with aligned stem cells, may synergistically contribute to the regeneration of the severely damaged peripheral nerve.
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IL-17RA is essential for optimal localization of follicular Th cells in the germinal center light zone to promote autoantibody-producing B cells.
J. Immunol.
PUBLISHED: 07-15-2013
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Germinal centers (GCs) provide a microenvironment that promotes and regulates the interactions of B cells with follicular Th (TFH) cells. In this study, we show that there are significantly higher frequencies of CXCR5(+)ICOS(+) TFH cells in autoimmune BXD2 mice, and these cells express both IL-21R and IL-17RA. Although IL-17 and IL-21 are both important for the formation of spontaneous GCs and development of pathogenic autoantibodies, IL-21, but not IL-17, is required for the proper development of TFH cells in BXD2 mice. The total numbers of TFH cells and their ability to induce B cell responses in vitro were not affected by a deficiency of IL-17RA in BXD2-Il17ra(-/-) mice, the majority of CXCR5(+) TFH cells from BXD2-Il17ra(-/-) mice were, however, not localized in the GC light zone (LZ). Interruption of IL-17 signaling, either acutely by AdIL-17R:Fc or chronically by Il17ra(-/-), disrupted TFH-B interactions and abrogated the generation of autoantibody-forming B cells in BXD2 mice. IL-17 upregulated the expression of regulator of G-protein signaling 16 (RGS16) to promote the ability of TFH to form conjugates with B cells, which was abolished in TFH cells from BXD2-Rgs16(-/-) mice. The results suggests that IL-17 is an extrinsic stop signal that it acts on postdifferentiated IL-17RA(+) TFH to enable its interaction with responder B cells in the LZ niche. These data suggest a novel concept that TFH differentiation and its stabilization in the LZ are two separate checkpoints and that IL-21 and IL-17 act at each checkpoint to enable pathogenic GC development.
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Long-Term Regeneration and Functional Recovery of a 15?mm Critical Nerve Gap Bridged by Tremella fuciformis Polysaccharide-Immobilized Polylactide Conduits.
Evid Based Complement Alternat Med
PUBLISHED: 06-17-2013
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Novel peripheral nerve conduits containing the negatively charged Tremella fuciformis polysaccharide (TF) were prepared, and their efficacy in bridging a critical nerve gap was evaluated. The conduits were made of poly(D,L-lactide) (PLA) with asymmetric microporous structure. TF was immobilized on the lumen surface of the nerve conduits after open air plasma activation. The TF-modified surface was characterized by the attenuated total reflection Fourier-transformed infrared spectroscopy and the scanning electron microscopy. TF modification was found to enhance the neurotrophic gene expression of C6 glioma cells in vitro. TF-modified PLA nerve conduits were tested for their ability to bridge a 15?mm gap of rat sciatic nerve. Nerve regeneration was monitored by the magnetic resonance imaging. Results showed that TF immobilization promoted the nerve connection in 6 weeks. The functional recovery in animals receiving TF-immobilized conduits was greater than in those receiving the bare conduits during an 8-month period. The degree of functional recovery reached ~90% after 8 months in the group of TF-immobilized conduits.
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Suspension bead array of the single-stranded multiplex polymerase chain reaction amplicons for enhanced identification and quantification of multiple pathogens.
Anal. Chem.
PUBLISHED: 05-16-2013
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Rapid identification of single and multiple infectious agents is vital in clinical settings and during biothreat attack. This study assesses the assay of single-stranded multiplex polymerase chain reaction (PCR) amplicons by suspension bead array (SSMP-SBA) for multiple pathogens identification in a single-tube reaction. A 15-plex assay for identification of 11 highly infectious pathogens was developed to evaluate the performance of SSMP-SBA. Pathogen-specific amplicons were obtained by sequential amplification of genomic DNAs using gene-specific primers tagged with artificial unique sequences and unique primers of which the reverse primer was modified by biotin and phosphorothioate. The SSMP products generated by T7 exonuclease-mediated DNA hydrolysis were hybridized to 15 sets of beads coupled with gene-specific and control oligonucleotide probes for pathogen identification and quantification by flow cytometry. This method was validated via assessment of 57 reference strains and one clinical bacterial isolate. All 11 pathogens can be detected by the 15-plex SSMP-SBA assay, and this design significantly enhanced the signal-to-noise ratio and improved the assay performance. This assay achieves similar sensitivity to our in-house real-time PCR system with the limit of detection equivalent to 5-100 genome copies and a linear dynamic range crossing three to five logs. In the validation assay, a 100% accuracy rate was achieved when the pathogens were among the target species. Notably, the species of pathogens were accurately identified from the samples with multiple infections. SSMP-SBA presents superior performance with multiplexing capability in a single-tube reaction and provides a new approach for detection and species identification of multiple pathogen infections.
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Need-based intervention is an effective strategy for improving the nutritional status of older people living in a nursing home: a randomized controlled trial.
Int J Nurs Stud
PUBLISHED: 03-29-2013
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Nutrition is a key element in geriatric health. Protein-energy malnutrition is common in institutionalized persons.
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Cutting Edge: defective follicular exclusion of apoptotic antigens due to marginal zone macrophage defects in autoimmune BXD2 mice.
J. Immunol.
PUBLISHED: 03-29-2013
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Marginal zone macrophages (MZMs) act as a barrier to entry of circulating apoptotic debris into the follicles of secondary lymphoid organs. In autoimmune BXD2 mice, there is a progressive reduction in the function and numbers of MZMs. Absence of MZMs results in retention of apoptotic cell (AC) debris within the marginal zone (MZ) and increased loading of AC Ags on MZ B cells and MZ-precursor (MZ-P) B cells. The MZ-P B cells are capable of translocating the AC Ags to the follicular zone and stimulating T cells. Both MZMs and MZ-P B cells from BXD2 mice express low levels of tolerogenic signals and high levels of inflammatory signals. Thus, the current study suggests a multifaceted mechanism in which MZMs maintain tolerance to apoptotic autoantigens and suppress their translocation to follicles. Lack of clearance of apoptotic debris by MZMs drives follicular Ag-transportation by MZ-P B cells to stimulate an autoimmune response.
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Mesenchymal stem cells from a hypoxic culture improve and engraft Achilles tendon repair.
Am J Sports Med
PUBLISHED: 03-28-2013
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Bone marrow-derived mesenchymal stem cells (MSCs) from humans cultured under hypoxic conditions increase bone healing capacity.
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Spheroid formation and enhanced cardiomyogenic potential of adipose-derived stem cells grown on chitosan.
Biores Open Access
PUBLISHED: 03-22-2013
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Mesenchymal stem cells may differentiate into cardiomyocytes and participate in local tissue repair after heart injury. In the current study, rat adipose-derived adult stem cells (ASCs) grown on chitosan membranes were observed to form cell spheroids after 3 days. The cell seeding density and surface modification of chitosan with Arg-Gly-Asp-containing peptide had an influence on the sizes of ASC spheroids. In the absence of induction, these spheroids showed an increased level of cardiac marker gene expression (Gata4, Nkx2-5, Myh6, and Tnnt2) more than 20-fold versus cells on the tissue culture polystyrene (TCPS) dish. Induction by 5-azacytidine or p38 MAP kinase inhibitor (SB202190) did not further increase the cardiac marker gene expression of these spheroids. Moreover, the enhanced cardiomyogenic potential of the spheroids was highly associated with the chitosan substrates. When ASC spheroids were plated onto TCPS with either basal or cardiac induction medium for 9 days, the spheroids spread into a monolayer and the positive effect on cardiomyogenic marker gene expression disappeared. The possible role of calcium ion and the up-regulation of adhesion molecule P-selectin and chemokine receptor Cxcr4 were demonstrated in ASC spheroids. Applying these spheroids to the chronic myocardial infarction animal model showed better functional recovery versus single cells after 12 weeks. Taken together, this study suggested that the ASC spheroids on chitosan may form as a result of calcium ion signaling, and the transplantation of these spheroids may offer a simple method to enhance the efficiency of stem cell-based therapy in myocardial infarction.
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Death receptor 5-targeted depletion of interleukin-23-producing macrophages, Th17, and Th1/17 associated with defective tyrosine phosphatase in mice and patients with rheumatoid arthritis.
Arthritis Rheum.
PUBLISHED: 03-19-2013
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Bidirectional interactions between granulocyte-macrophage colony-stimulating factor-positive (GM-CSF+) T cells and interferon regulatory factor 5-positive (IRF-5+) macrophages play a major role in autoimmunity. In the absence of SH2 domain-containing phosphatase 1 (SHP-1), GM-CSF-stimulated cells are resistant to death receptor (DR)-mediated apoptosis. The objective of this study was to determine whether TRA-8, an anti-DR5 agonistic antibody, can eliminate inflammatory macrophages and CD4 T cells in the SHP-1-deficient condition.
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Validation of Memorial Sloan-Kettering Cancer Center nomogram for prediction of non-sentinel lymph node metastasis in sentinel lymph node positive breast cancer patients an international comparison.
Int J Surg
PUBLISHED: 03-14-2013
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Current guidelines for breast cancer treatment recommend completion axillary lymph node dissection (CALND) following in case of positive sentinel lymph node (SLN) metastasis, which only in 35%-70% shows additional nodal metastases. Several nomograms and scoring systems have been created to predict the risk of metastasis in non-SLNs. The aim of the study was to identify individual patient risk for non-sentinel lymph node metastasis by validating with MSKCC nomogram and to evaluate the variability within a group of SLN-positive breast cancer patients with the final goal of avoiding unnecessary CALND.
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Microwell chips for selection of bio-macromolecules that increase the differentiation capacities of mesenchymal stem cells.
Macromol Biosci
PUBLISHED: 03-08-2013
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Microwell chips (25?mm?×?25?mm) are fabricated to select proper substrates for growing three-dimensional (3D) spheroids from mesenchymal stem cells (MSCs). Different bio-macromolecules and their combinations are immobilized on the chip by air plasma treatment and by polyelectrolyte interaction. Only a small number of MSCs (?10(5) ) are needed for each chip. The expression level of N-cadherin, a cell-adhesion molecule, is used as an indicator for cell-cell interactions. MSC spheroids expressing the highest N-cadherin level also show the greatest osteogenic potential. The microwell chip may be used as an efficient platform to screen bio-macromolecules that enhance the differentiation potential of MSCs.
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Effectiveness of Japanese SHARE model in improving Taiwanese healthcare personnels preference for cancer truth telling.
Psychooncology
PUBLISHED: 03-07-2013
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Communication skills training (CST) based on the Japanese SHARE model of family-centered truth telling in Asian countries has been adopted in Taiwan. However, its effectiveness in Taiwan has only been preliminarily verified. This study aimed to test the effect of SHARE model-centered CST on Taiwanese healthcare providers truth-telling preference, to determine the effect size, and to compare the effect of 1-day and 2-day CST programs on participants truth-telling preference.
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Substrate-dependent Wnt signaling in MSC differentiation within biomaterial-derived 3D spheroids.
Biomaterials
PUBLISHED: 02-25-2013
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A unique biomaterial-based system was developed to generate dynamic three-dimensional (3D) multicellular spheroids of mesenchymal stem cells (MSCs). MSCs were cultured on transparent membranes made of chitosan or those further grafted with hyaluronan (HA) in different densities. MSCs vigorously migrated and were self-assembled into highly mobile 3D spheroids with substrate-dependent upregulation of adhesion molecule N-cadherin. MSC spheroids showed increased expression of Wnt genes/proteins and substrate-dependent cell fate. The correlation of differentiation capacities with Wnt signaling and crosstalk with other pathways such as ERK1/2 or Smad2/3 were observed for MSC spheroids but not for the conventional 2D cultured cells. Wnt3a-mediated canonical Wnt signaling was more active for MSC spheroids derived on chitosan, which were prone to osteogenesis. Wnt5a-mediated non-canonical Wnt signaling was more active for MSC spheroids derived on HA-grafted chitosan, which were prone to chondrogenesis. In particular, the relative importance of Wnt5a-mediated non-canonical vs. Wnt3a-mediated canonical Wnt signals in determining the cell fate was controlled by the grafting density of HA on chitosan. Treatment with the inhibitor of canonical Wnt-associated signaling molecules suppressed the osteogenesis of MSC spheroids on chitosan. This study demonstrates that Wnt signaling of MSCs is distinct in 3D environment and is substrate-dependent. The convenient 3D platform may be used to examine the role of Wnt signaling in controlling MSC fate under different extracellular environments, and potentially applied to study stem cell behavior in regenerative medicine, normal development, and cancer.
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An improved bioassay facilitates the screening of repellents against cat flea, Ctenocephalides felis (Siphonaptera: Pulicidae).
Pest Manag. Sci.
PUBLISHED: 02-21-2013
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Repellents are a common method for preventing flea bites, making an effective system for flea repellent screening advantageous. We describe an improved technique to facilitate repellent activity screening of numerous plant-based Ctenocephalides felis (cat flea) repellents.
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Suppressive effects of anthrax lethal toxin on megakaryopoiesis.
PLoS ONE
PUBLISHED: 02-15-2013
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Anthrax lethal toxin (LT) is a major virulence factor of Bacillus anthracis. LT challenge suppresses platelet counts and platelet function in mice, however, the mechanism responsible for thrombocytopenia remains unclear. LT inhibits cellular mitogen-activated protein kinases (MAPKs), which are vital pathways responsible for cell survival, differentiation, and maturation. One of the MAPKs, the MEK1/2-extracellular signal-regulated kinase pathway, is particularly important in megakaryopoiesis. This study evaluates the hypothesis that LT may suppress the progenitor cells of platelets, thereby inducing thrombocytopenic responses. Using cord blood-derived CD34(+) cells and mouse bone marrow mononuclear cells to perform in vitro differentiation, this work shows that LT suppresses megakaryopoiesis by reducing the survival of megakaryocytes. Thrombopoietin treatments can reduce thrombocytopenia, megakaryocytic suppression, and the quick onset of lethality in LT-challenged mice. These results suggest that megakaryocytic suppression is one of the mechanisms by which LT induces thrombocytopenia. These findings may provide new insights for developing feasible approaches against anthrax.
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The role of RhoA kinase inhibition in human placenta-derived multipotent cells on neural phenotype and cell survival.
Biomaterials
PUBLISHED: 02-12-2013
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Current advances in stem cell biology have brought much hope for therapy of neuro-degenerative diseases. However, neural stem cells (NSCs) are rare adult stem cells, and the use of non-NSCs requires efficient and high-yielding lineage-specific differentiation prior to transplantation for efficacy. We report on the efficient differentiation of placental-derived multipotent cells (PDMCs) into a neural phenotype with use of Y-27632, a clinically compliant small molecular inhibitor of Rho kinase (ROCK) which is a major mediator of cytoskeleton dynamics. Y-27632 does not induce differentiation of PDMC toward the mesodermal lineages of adipogenesis and osteogenesis, but rather a neural-like morphology, with rapid development of cell extensions and processes within 24 h. Compared with conventional neurogenic differentiation agents, Y-27632 induces a higher percentage of neural-like cells in PDMCs without arresting proliferation or cell cycle dynamics. Y-27632-treated PDMCs express several neural lineage genes at the RNA and protein level, including nestin, MAP2, and GFAP. The effect of the ROCK inhibitor is cell-specific to PDMCs, and is mainly mediated through the ROCK2 isoform and its downstream target, myosin II. Our data suggest that ROCK inhibition and cytoskeletal rearrangement may allow for induction of a neural phenotype in PDMCs without compromising cell survival.
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Bilateral persistent trigeminal arteries with unilateral trigeminal artery to cavernous sinus fistula. A case report.
Interv Neuroradiol
PUBLISHED: 02-10-2013
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A 59-year-old man who denied a history of trauma presented with left pulsatile tinnitus and left orbital swelling for six months. Digital subtraction angiography showed a left persistent trigeminal artery (PTA) with a trigeminal artery to cavernous sinus (trigeminal-cavernous sinus) fistula and a right PTA. Transarterial detachable coil embolization of the left trigeminal-cavernous sinus fistula was performed, and the symptoms subsided. There has been no report of bilateral PTAs with a spontaneous fistula connected from one PTA to the ipsilateral cavernous sinus. This paper reports such a rare circumstance.
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The effects of comorbidities on the trajectory of depressive symptoms among older adults in Taiwan.
J Psychosom Res
PUBLISHED: 02-08-2013
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This study aimed to identify depressive symptoms among older Taiwanese adults and to explore the relationships between different comorbidities and depressive symptoms.
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Bacterial cellulose and bacterial cellulose-chitosan membranes for wound dressing applications.
Carbohydr Polym
PUBLISHED: 01-25-2013
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Bacterial cellulose (BC) and bacterial cellulose-chitosan (BC-Ch) membranes were successfully produced in large scale. BC was synthesized by Acetobacter xylinum. BC-Ch was prepared by immersing BC in chitosan followed by freeze-drying. The surface morphology of BC and BC-Ch membranes were examined by a scanning electron microscope (SEM). SEM images showed that BC-Ch possessed a denser fibril network with smaller pores than BC. Infrared spectroscopy was used to confirm the incorporation of chitosan in BC-Ch. The swelling behavior, water retention capacity, and mechanical properties of BC and BC-Ch were further evaluated. Results indicated that both membranes maintained proper moisture contents for an extensive period without dehydration. The tensile strength and elongation at break for BC-Ch were slightly lower while the Youngs modulus was higher. Cell culture studies demonstrated that BC and BC-Ch had no cytotoxicity. In the antibacterial test, the addition of chitosan in BC showed significant growth inhibition against Escherichia coli and Staphylococcus aureus. The effects of BC and BC-Ch on skin wound healing were assessed by rat models. Histological examinations revealed that wounds treated with BC-Ch epithelialized and regenerated faster than those treated with BC or Tegaderm. Therefore, BC-Ch was considered as a potential candidate for wound dressing materials.
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In vitro and in vivo evaluation of chitosan-gelatin scaffolds for cartilage tissue engineering.
Mater Sci Eng C Mater Biol Appl
PUBLISHED: 01-21-2013
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Chitosan-gelatin polyelectrolyte complexes were fabricated and evaluated as tissue engineering scaffolds for cartilage regeneration in vitro and in vivo. The crosslinker for the gelatin component was selected among glutaraldehyde, bisepoxy, and a water-soluble carbodiimide (WSC) based upon the proliferation of chondrocytes on the crosslinked gelatin. WSC was found to be the most suitable crosslinker. Complex scaffolds made from chitosan and gelatin with a component ratio equal to one possessed the proper degradation rate and mechanical stability in vitro. Chondrocytes were able to proliferate well and secrete abundant extracellular matrix in the chitosan-gelatin (1:1) complex scaffolds crosslinked by WSC (C1G1WSC) compared to the non-crosslinked scaffolds. Implantation of chondrocytes-seeded scaffolds in the defects of rabbit articular cartilage confirmed that C1G1WSC promoted the cartilage regeneration. The neotissue formed the histological feature of tide line and lacunae in 6.5 months. The amount of glycosaminoglycans in C1G1WSC constructs (0.187±0.095 ?g/mg tissue) harvested from the animals after 6.5 months was 14 wt.% of that in normal cartilage (1.329±0.660 ?g/mg tissue). The average compressive modulus of regenerated tissue at 6.5 months was about 0.539 MPa, which approached to that of normal cartilage (0.735 MPa), while that in the blank control (3.881 MPa) was much higher and typical for fibrous tissue. Type II collagen expression in C1G1WSC constructs was similarly intense as that in the normal hyaline cartilage. According to the above results, the use of C1G1WSC scaffolds may enhance the cartilage regeneration in vitro and in vivo.
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A new microsporidium, Triwangia caridinae gen. nov., sp. nov. parasitizing fresh water shrimp, Caridina formosae (Decapoda: Atyidae) in Taiwan.
J. Invertebr. Pathol.
PUBLISHED: 01-11-2013
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A new microsporidium was isolated from the endemic, Taiwanese shrimp, Caridina formosae (Decapoda, Atyidae) from northern Taiwan. A conspicuous symptom of infection was presence of opaque white xenomas located in the proximity of the alimentary tract, the surface of the hepatopancreas, and the gills. A fully developed xenoma consisted of a hard, thick capsule filled with sporophorous vesicles containing multiple spores. Microsporidia developed synchronously within the same sporophorous vesicle, although the stage of parasite development differed among the vesicles. Fresh spores were pyriform, mononucleated and measured 6.53 × 4.38 ?m. The polar filament was anisofilar with 9-11 coils. Phylogenetic analysis based on the small subunit ribosomal DNA sequence showed that the isolate is most similar to the fish microsporidian clade containing the genera Kabatana, Microgemma, Potaspora, Spraguea, and Teramicra. The highest sequence identity, 80%, was with Spraguea spp. Based on pathogenesis, life cycle and phylogenetic analysis, we erect a new genus and species, Triwangia caridinae for the novel microsporidium.
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