1,762 research outputs found

    Rice protein radicals: growth and stability under microwave treatment

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    Low-molecular-weight heparin reduces hyperoxia-augmented ventilator-induced lung injury via serine/threonine kinase-protein kinase B

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    <p>Abstract</p> <p>Background</p> <p>High-tidal-volume mechanical ventilation and hyperoxia used in patients with acute lung injury (ALI) can induce the release of cytokines, including high-mobility group box-1 (HMGB1), oxygen radicals, neutrophil infiltration, and the disruption of epithelial and endothelial barriers. Hyperoxia has been shown to increase ventilator-induced lung injury, but the mechanisms regulating interaction between high tidal volume and hyperoxia are unclear. We hypothesized that subcutaneous injections of enoxaparin would decrease the effects of hyperoxia on high-tidal-volume ventilation-induced HMGB1 production and neutrophil infiltration via the serine/threonine kinase/protein kinase B (Akt) pathway.</p> <p>Methods</p> <p>Male C57BL/6, either wild type or Akt<sup>+/-</sup>, aged between 6 and 8 weeks, weighing between 20 and 25 g, were exposed to high-tidal-volume (30 ml/kg) mechanical ventilation with room air or hyperoxia for 2 to 8 hours with or without 4 mg/kg enoxaparin administration. Nonventilated mice served as a control group. Evan blue dye, lung wet-to-dry weight ratio, free radicals, myeloperoxidase, Western blot of Akt, and gene expression of HMGB1 were measured. The expression of HMGB1 was studied by immunohistochemistry.</p> <p>Results</p> <p>High-tidal-volume ventilation using hyperoxia induced microvascular permeability, Akt activation, HMGB1 mRNA expression, neutrophil infiltration, oxygen radicals, HMGB1 production, and positive staining of Akt in bronchial epithelium. Hyperoxia-induced augmentation of ventilator-induced lung injury was attenuated with Akt deficient mice and pharmacological inhibition of Akt activity by enoxaparin.</p> <p>Conclusion</p> <p>These data suggest that enoxaparin attenuates hyperoxia-augmented high-tidal-volume ventilation-induced neutrophil influx and HMGB1 production through inhibition of the Akt pathway. Understanding the protective mechanism of enoxaparin related with the reduction of HMGB1 may help further knowledge of the effects of mechanical forces in the lung and development of possible therapeutic strategies involved in acute lung injury.</p

    A cross-sectional study on attitudes toward gender equality, sexual behavior, positive sexual experiences, and communication about sex among sexually active and non-sexually active adolescents in Bolivia and Ecuador

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    Background: It is widely agreed upon that gender is a key aspect of sexuality however, questions remain on how gender exactly influences adolescents’ sexual health. Objective: The aim of this research was to study correlations between gender equality attitudes and sexual behavior, sexual experiences and communication about sex among sexually active and non-sexually active adolescents in 2 Latin American countries. Design: In 2011, a cross-sectional study was carried out among 5,913 adolescents aged 14–18 in 20 secondary schools in Cochabamba (Bolivia) and 6 secondary schools in Cuenca (Ecuador). Models were built using logistic regressions to assess the predictive value of attitudes toward gender equality on adolescents’ sexual behavior, on experiences and on communication. Results: The analysis shows that sexually active adolescents who consider gender equality as important report higher current use of contraceptives within the couple. They are more likely to describe their last sexual intercourse as a positive experience and consider it easier to talk with their partner about sexuality than sexually experienced adolescents who are less positively inclined toward gender equality. These correlations remained consistent whether the respondent was a boy or a girl. Non-sexually active adolescents, who consider gender equality to be important, are more likely to think that sexual intercourse is a positive experience. They consider it less necessary to have sexual intercourse to maintain a relationship and find it easier to communicate with their girlfriend or boyfriend than sexually non-active adolescents who consider gender equality to be less important. Comparable results were found for boys and girls. Conclusions: Our results suggest that gender equality attitudes have a positive impact on adolescents’ sexual and reproductive health (SRH) and wellbeing. Further research is necessary to better understand the relationship between gender attitudes and specific SRH outcomes such as unwanted teenage pregnancies and sexual pleasure among adolescents worldwide

    Effect of 1,25-(OH)2D3 on proliferation of fibroblast-like synoviocytes and expressions of pro-inflammatory cytokines through regulating MicroRNA-22 in a rat model of rheumatoid arthritis

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    Objective: This study aims to investigate the regulatory mechanism of 1,25-(OH)2D3 on the proliferation of fibroblast-like synoviocytes (FLS) and expressions of pro-inflammatory cytokines in rheumatoid arthritis (RA) rats via microRNA-22 (miR-22).Methods: A rat model of RA was established with a subcutaneous injection of type II collagen. After treated with different concentrations of 1,25-(OH)2D3 the proliferation of FLS was estimated by the MTT method, and the optimal concentration of 1,25-(OH)2D3 was selected for further experiments. Cell proliferation was detected by MTT. Cell cycle and apoptosis were analyzed by FCM. The IL-1β, IL-6, IL-8, and PGE2 protein expressions were determined by ELISA, and MMP-3, INOS, and Cox-2 mRNA expressions were measured by qRT-PCR.Results: The rat model of RA was successfully established. Compared with the blank group, the 1,25-(OH)2D3 and miR-22 inhibitors groups exhibited higher proliferation inhibition and apoptosis rates, lower levels of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, and PGE2), and decreased mRNA expressions of MMP-3, INOS, and Cox-2. The miR-22 mimics group had lower proliferation inhibition and apoptosis rates, elevated expressions of pro-inflammatory cytokines and MMP-3, INOS, and Cox-2 than the blank group. In contrast to the 1,25-(OH)2D3 group, the proliferation inhibition and apoptosis rates were down-regulated, and the expressions of pro-inflammatory cytokines and MMP-3, INOS, and Cox-2 were up-regulated in the 1,25-(OH)2D3 + miR-22 mimics group.Conclusion: Our study demonstrated that 1,25-(OH)2D3 inhibits the proliferation of FLS and alleviates inflammatory response in RA rats by down-regulating miR-22

    Alternative splicing and nonsense-mediated decay regulate telomerase reverse transcriptase (TERT) expression during virus-induced lymphomagenesis in vivo

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    <p>Abstract</p> <p>Background</p> <p>Telomerase activation, a critical step in cell immortalization and oncogenesis, is partly regulated by alternative splicing. In this study, we aimed to use the Marek's disease virus (MDV) T-cell lymphoma model to evaluate TERT regulation by splicing during lymphomagenesis <it>in vivo</it>, from the start point to tumor establishment.</p> <p>Results</p> <p>We first screened cDNA libraries from the chicken MDV lymphoma-derived MSB-1 T- cell line, which we compared with B (DT40) and hepatocyte (LMH) cell lines. The chTERT splicing pattern was cell line-specific, despite similar high levels of telomerase activity. We identified 27 alternative transcripts of chicken TERT (chTERT). Five were in-frame alternative transcripts without <it>in vitro </it>telomerase activity in the presence of viral or chicken telomerase RNA (vTR or chTR), unlike the full-length transcript. Nineteen of the 22 transcripts with a premature termination codon (PTC) harbored a PTC more than 50 nucleotides upstream from the 3' splice junction, and were therefore predicted targets for nonsense-mediated decay (NMD). The major PTC-containing alternatively spliced form identified in MSB1 (ie10) was targeted to the NMD pathway, as demonstrated by UPF1 silencing. We then studied three splicing events separately, and the balance between in-frame alternative splice variants (d5f and d10f) plus the NMD target i10ec and constitutively spliced chTERT transcripts during lymphomagenesis induced by MDV indicated that basal telomerase activity in normal T cells was associated with a high proportion of in-frame non functional isoforms and a low proportion of constitutively spliced chTERT. Telomerase upregulation depended on an increase in active constitutively spliced chTERT levels and coincided with a switch in alternative splicing from an in-frame variant to NMD-targeted variants.</p> <p>Conclusions</p> <p>TERT regulation by splicing plays a key role in telomerase upregulation during lymphomagenesis, through the sophisticated control of constitutive and alternative splicing. Using the MDV T-cell lymphoma model, we identified a chTERT splice variant as a new NMD target.</p

    Stokes solitons in optical microcavities

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    Solitons are wave packets that resist dispersion through a self-induced potential well. They are studied in many fields, but are especially well known in optics on account of the relative ease of their formation and control in optical fibre waveguides. Besides their many interesting properties, solitons are important to optical continuum generation, in mode-locked lasers, and have been considered as a natural way to convey data over great distances. Recently, solitons have been realized in microcavities, thereby bringing the power of microfabrication methods to future applications. This work reports a soliton not previously observed in optical systems, the Stokes soliton. The Stokes soliton forms and regenerates by optimizing its Raman interaction in space and time within an optical potential well shared with another soliton. The Stokes and the initial soliton belong to distinct transverse mode families and benefit from a form of soliton trapping that is new to microcavities and soliton lasers in general. The discovery of a new optical soliton can impact work in other areas of photonics, including nonlinear optics and spectroscopy

    Immune complex formation impairs the elimination of solutes from the brain: implications for immunotherapy in Alzheimer's disease

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    Background: Basement membranes in the walls of cerebral capillaries and arteries form a major lymphatic drainage pathway for fluid and solutes from the brain. Amyloid-β (Aβ) draining from the brain is deposited in such perivascular pathways as cerebral amyloid angiopathy (CAA) in Alzheimer's disease (AD). CAA increases in severity when Aβ is removed from the brain parenchyma by immunotherapy for AD. In this study we investigated the consequences of immune complexes in artery walls upon drainage of solutes similar to soluble Aβ. We tested the hypothesis that, following active immunization with ovalbumin, immune complexes form within the walls of cerebral arteries and impair the perivascular drainage of solutes from the brain. Mice were immunized against ovalbumin and then challenged by intracerebral microinjection of ovalbumin. Perivascular drainage of solutes was quantified following intracerebral microinjection of soluble fluorescent 3kDa dextran into the brain at different time intervals after intracerebral challenge with ovalbumin. Results: Ovalbumin, IgG and complement C3 co-localized in basement membranes of artery walls 24 hrs after challenge with antigen; this was associated with significantly reduced drainage of dextran in immunized mice. Conclusions: Perivascular drainage along artery walls returned to normal by 7 days. These results indicate that immune complexes form in association with basement membranes of cerebral arteries and interfere transiently with perivascular drainage of solutes from the brain. Immune complexes formed during immunotherapy for AD may similarly impair perivascular drainage of soluble Aβ and increase severity of CAA

    Expression of HIWI in human esophageal squamous cell carcinoma is significantly associated with poorer prognosis

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    <p>Abstract</p> <p>Background</p> <p>HIWI, the human homologue of Piwi family, is present in CD34<sup>+ </sup>hematopoietic stem cells and germ cells, but not in well-differentiated cell populations, indicating that HIWI may play an impotent role in determining or maintaining stemness of these cells. That HIWI expression has been detected in several type tumours may suggest its association with clinical outcome in cancer patients.</p> <p>Methods</p> <p>With the methods of real-time PCR, western blot, immunocytochemistry and immunohistochemistry, the expression of HIWI in three esophageal squamous cancer cell lines KYSE70, KYSE140 and KYSE450 has been characterized. Then, we investigated HIWI expression in a series of 153 esophageal squamous cell carcinomas using immunohistochemistry and explored its association with clinicopathological features.</p> <p>Results</p> <p>The expression of HIWI was observed in tumour cell nuclei or/and cytoplasm in 137 (89.5%) cases, 16 (10.5%) cases were negative in both nuclei and cytoplasm. 86 (56.2%) were strongly positive in cytoplasm, while 49 (32.0%) were strongly positive in nuclei. The expression level of HIWI in cytoplasm of esophageal cancer cells was significantly associated with histological grade (<it>P </it>= 0.011), T stage (<it>P </it>= 0.035), and clinic outcome (<it>P </it>< 0.001), while there was no correlation between the nuclear HIWI expression and clinicopathological features.</p> <p>Conclusion</p> <p>The expression of HIWI in the cytoplasm of esophageal cancer cells is significantly associated with higher histological grade, clinical stage and poorer clinical outcome, indicating its possible involvement in cancer development.</p

    Targeting colorectal cancer stem cells with inducible caspase-9

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    Colorectal cancer stem cells (CSCs) drive tumor growth and are suggested to initiate distant metastases. Moreover, colon CSCs are reportedly more resistant to conventional chemotherapy, which is in part due to upregulation of anti-apoptotic Bcl-2 family members. To determine whether we could circumvent this apoptotic blockade, we made use of an inducible active caspase-9 (iCasp9) construct to target CSCs. Dimerization of iCasp9 with AP20187 in HCT116 colorectal cancer cells resulted in massive and rapid induction of apoptosis. In contrast to fluorouracil (5-FU)-induced apoptosis, iCasp9-induced apoptosis was independent of the mitochondrial pathway as evidenced by Bax/Bak double deficient HCT116 cells. Dimerizer treatment of colon CSCs transduced with iCasp9 (CSC-iCasp9) also rapidly induced high levels of apoptosis, while these cells were unresponsive to 5-FU in vitro. More importantly, injection of the dimerizer into mice that developed a colon CSC-iCasp9-induced tumor resulted in a strong decrease in tumor size, an increase in tumor cell apoptosis and a clear loss of CD133+ CSCs. Taken together, our data indicate that dimerization of iCasp9 circumvents the apoptosis block in CSCs, which results in effective tumor regression in vivo
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