394 research outputs found

    Removal of alkali and transition metal ions from water with hydrophobic deep eutectic solvents

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    Hydrophobic deep eutectic solvents were used for the first time for the removal of metal ions from non-buffered water. It was shown that the extraction occurs via an ion exchange mechanism in which all transition metal ions could be extracted with high distribution coefficients, even for high Co2+ concentrations and low DES/water mass ratios. Maximum extraction efficiency could be reached within 5 s and regeneration was possible.<br/

    Fluid intake and clinicopathological characteristics of bladder cancer:the West Midlands Bladder Cancer Prognosis Programme (BCPP)

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    Objective Between 10 and 20% of bladder cancer patients who are diagnosed with nonmuscle-invasive bladder cancer will progress to muscle-invasive disease. Risk of progression depends on several factors at diagnosis including age, tumour stage, grade, size and number, and the presence or absence of carcinoma in situ. Fluid intake may be related to these factors. Methods Data of 1123 participants from the West Midlands Bladder Cancer Prognosis Programme were used. Data collection was via a semistructured questionnaire, and case report forms were used to collect clinicopathological data. Fluid intake was measured for six main categories: alcoholic fluids, hot fluids, fruit fluids, milk, fizzy drinks, and water, and converted into quintile variables. Multilevel mixed-effects linear regression was performed for every beverage category per clinicopathological variable and corrected for age, gender, and smoking status. Results Age at diagnosis was distributed differently amongst those in different total fluid intake quintiles (predicted means 71.5, 70.9, 71.5, 69.9, and 67.4, respectively) and showed a significant inverse linear trend in alcohol (P <0.01), hot fluids (P <0.01), and total fluids intake (P <0.01), in nonmuscle-invasive bladder cancer patients. Conclusion Our results suggest an inverse association for alcohol intake and total fluid intake with age at diagnosis. These results should be confirmed by future studies, alongside a possible (biological) mechanism that could influence tumour growth, and the effect of micturition frequency

    β1 Integrins Mediate Attachment of Mesenchymal Stem Cells to Cartilage Lesions

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    Mesenchymal stem cells (MSC) may have great potential for cell-based therapies of osteoarthritis. However, after injection in the joint, only few cells adhere to defective articular cartilage and contribute to cartilage regeneration. Little is known about the molecular mechanisms of MSC attachment to defective articular cartilage. Here, we developed an ex vivo attachment system, using rat osteochondral explants with artificially created full-thickness cartilage defects in combination with genetically labeled MSC isolated from bone marrow of human placental alkaline phosphatase transgenic rats. Binding of MSC to full-thickness cartilage lesions was improved by serum, but not hyaluronic acid, and was dependent on the presence of divalent cations. Additional in vitro tests showed that rat MSC attach, in a divalent cation-dependent manner, to collagen I, collagen II, and fibronectin, but not to collagen XXII or cartilage oligomeric matrix protein (COMP). RGD peptides partially blocked the adhesion of MSC to fibronectin in vitro and to cartilage lesions ex vivo. Furthermore, the attachment of MSC to collagen I and II in vitro and to cartilage lesions ex vivo was almost completely abolished in the presence of a β1 integrin blocking antibody. In conclusion, our data suggest that attachment of MSC to ex vivo full-thickness cartilage lesions is almost entirely β1 integrin-mediated, whereby both RGD- and collagen-binding integrins are involved. These findings suggest a key role of integrins during MSC attachment to defective cartilage and may pave the way for improved MSC-based therapies in the future

    Improved cartilage integration and interfacial strength after enzymatic treatment in a cartilage transplantation model

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    The objective of the present study was to investigate whether treatment of articular cartilage with hyaluronidase and collagenase enhances histological and mechanical integration of a cartilage graft into a defect. Discs of 3 mm diameter were taken from 8-mm diameter bovine cartilage explants. Both discs and annulus were either treated for 24 hours with 0.1% hyaluronidase followed by 24 hours with 10 U/ml collagenase or left untreated (controls). Discs and annulus were reassembled and implanted subcutaneously in nude mice for 5 weeks. Integration of disc with surrounding cartilage was assessed histologically and tested biomechanically by performing a push-out test. After 5 weeks a significant increase in viable cell counts was seen in wound edges of the enzyme-treated group as compared with controls. Furthermore, matrix integration (expressed as a percentage of the total interface length that was connected; mean ± standard error) was 83 ± 15% in the treated samples versus 44 ± 40% in the untreated controls. In the enzyme-treated group only, picro-Sirius Red staining revealed collagen crossing the interface perpendicular to the wound surface. Immunohistochemical analyses demonstrated that the interface tissue contained cartilage-specific collagen type II. Collagen type I was found only in a small region of fibrous tissue at the level of the superficial layer, and collagen type III was completely absent in both groups. A significant difference in interfacial strength was found using the push-out test: 1.32 ± 0.15 MPa in the enzyme-treated group versus 0.84 ± 0.14 MPa in the untreated controls. The study shows that enzyme treatment of cartilage wounds increases histological integration and improves biomechanical bonding strength. Enzymatic treatment may represent a promising addition to current techniques for articular cartilage repair

    Recellularization of auricular cartilage via elastase-generated channels

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    Decellularized tissue matrices are promising substrates for tissue generation by stem cells to replace poorly regenerating tissues such as cartilage. However, the dense matrix of decellularized cartilage impedes colonisation by stem cells. Here, we show that digestion of elastin fibre bundles traversing auricular cartilage creates channels through which cells can migrate into the matrix. Human chondrocytes and bone marrow-derived mesenchymal stromal cells efficiently colonise elastin-treated scaffolds through these channels, restoring a glycosaminoglycan-rich matrix and improving mechanical properties while maintaining size and shape of the restored tiss

    Developing quality indicators for the care of HIV-infected pregnant women in the Dutch Caribbean

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    <p>Abstract</p> <p>Background</p> <p>Effective interventions to prevent mother-to-child HIV transmission (PMTCT) exist and when properly applied reduce the risk of vertical HIV transmission. As part of optimizing PMTCT in the Dutch Caribbean we developed a set of valid and applicable indicators in order to assess the quality of care in HIV-infected (pregnant) women and their newborns.</p> <p>Methods</p> <p>A multidisciplinary expert panel of 19 experts reviewed and prioritized recommendations extracted from locally used international PMTCT guidelines according to a 3-step-modified-Delphi procedure. Subsequently, the feasibility, sample size, inter-observer reliability, sensitivity to change and case mixed stability of the potential indicators were tested for a data set of 153 HIV-infected women, 108 pregnancies of HIV-infected women and 79 newborns of HIV-infected women in Aruba, Curaçao and St Maarten from 2000 to 2010.</p> <p>Results</p> <p>The panel selected and prioritized 13 potential indicators. Applicability could not be tested for 4 indicators regarding HIV-screening in pregnant women because of lack of data. Four indicators performed satisfactorily for Curaçao ('monitoring CD4-cell count', 'monitoring HIV-RNA levels', 'intrapartum antiretroviral therapy and infant prophylaxis if antepartum antiretroviral therapy was not received', 'scheduled caesarean delivery') and 3 for St Maarten ('monitoring CD4-cell count', 'monitoring HIV-RNA levels', 'discuss and provide combined antiretroviral therapy to all HIV-infected pregnant women') whilst none for Aruba.</p> <p>Conclusions</p> <p>A systemic evidence-and consensus-based approach was used to develop quality indicators in 3 Dutch Caribbean settings. The varying results of the applicability testing accentuate the necessity of applicability testing even in, at first, comparable settings.</p

    Long-term expansion, enhanced chondrogenic potential, and suppression of endochondral ossification of adult human MSCs via WNT signaling mo

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    Mesenchymal stem cells (MSCs) are a potential source of chondrogenic cells for the treatment of cartilage disorders, but loss of chondrogenic potential during in vitro expansion and the propensity of cartilage to undergo hypertrophic maturation impede their therapeutic application. Here we report that the signaling protein WNT3A, in combination with FGF2, supports long-term expansion of human bone marrow-derived MSCs. The cells retained their chondrogenic potential and other phenotypic and functional properties of multipotent MSCs, which were gradually lost in the absence of WNT3A. Moreover, we discovered that endogenous WNT signals are the main drivers of the hypertrophic maturation that follows chondrogenic differentiation. Inhibition of WNT signals during differentiation prevented calcification and maintained cartilage properties following implantation in a mouse model. By maintaining potency during expansion and preventing hypertrophic maturation following differentiation, the modulation of WNT signaling removes two major obstacles that impede the clinical application of MSCs in cartilage repair
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