701 research outputs found

    Tyrosine kinase inhibitor SU6668 represses chondrosarcoma growth via antiangiogenesis in vivo

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    BACKGROUND: As chondrosarcomas are resistant to chemotherapy and ionizing radiation, therapeutic options are limited. Radical surgery often cannot be performed. Therefore, additional therapies such as antiangiogenesis represent a promising strategy for overcoming limitations in chondrosarcoma therapy. There is strong experimental evidence that SU6668, an inhibitor of the angiogenic tyrosine kinases Flk-1/KDR, PDGFRbeta and FGFR1 can induce growth inhibition of various primary tumors. However, the effectiveness of SU6668 on malignant primary bone tumors such as chondrosarcomas has been rarely investigated. Therefore, the aim of this study was to investigate the effects of SU6668 on chondrosarcoma growth, angiogenesis and microcirculation in vivo. METHODS: In 10 male severe combined immunodeficient (SCID) mice, pieces of SW1353 chondrosarcomas were implanted into a cranial window preparation where the calvaria serves as the site for the orthotopic implantation of bone tumors. From day 7 after tumor implantation, five animals were treated with SU6668 (250 mg/kg body weight, s.c.) at intervals of 48 hours (SU6668), and five animals with the equivalent amount of the CMC-based vehicle (Control). Angiogenesis, microcirculation, and growth of SW 1353 tumors were analyzed by means of intravital microscopy. RESULTS: SU6668 induced a growth arrest of chondrosarcomas within 7 days after the initiation of the treatment. Compared to Controls, SU6668 decreased functional vessel density and tumor size, respectively, by 37% and 53% on day 28 after tumor implantation. The time course of the experiments demonstrated that the impact on angiogenesis preceded the anti-tumor effect. Histological and immunohistochemical results confirmed the intravital microscopy findings. CONCLUSION: SU6668 is a potent inhibitor of chondrosarcoma tumor growth in vivo. This effect appears to be induced by the antiangiogenic effects of SU6668, which are mediated by the inhibition of the key angiogenic receptor tyrosine kinases Flk-1/KDR, PDGFRbeta and FGFR1. The experimental data obtained provide rationale to further develop the strategy of the use of the angiogenesis inhibitor SU6668 in the treatment of chondrosarcomas in addition to established therapies such as surgery

    Cross-talk between cd1d-restricted nkt cells and γδ cells in t regulatory cell response

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    CD1d is a non-classical major histocompatibility class 1-like molecule which primarily presents either microbial or endogenous glycolipid antigens to T cells involved in innate immunity. Natural killer T (NKT) cells and a subpopulation of γδ T cells expressing the Vγ4 T cell receptor (TCR) recognize CD1d. NKT and Vγ4 T cells function in the innate immune response via rapid activation subsequent to infection and secrete large quantities of cytokines that both help control infection and modulate the developing adaptive immune response. T regulatory cells represent one cell population impacted by both NKT and Vγ4 T cells. This review discusses the evidence that NKT cells promote T regulatory cell activation both through direct interaction of NKT cell and dendritic cells and through NKT cell secretion of large amounts of TGFβ, IL-10 and IL-2. Recent studies have shown that CD1d-restricted Vγ4 T cells, in contrast to NKT cells, selectively kill T regulatory cells through a caspase-dependent mechanism. Vγ4 T cell elimination of the T regulatory cell population allows activation of autoimmune CD8+ effector cells leading to severe cardiac injury in a coxsackievirus B3 (CVB3) myocarditis model in mice. CD1d-restricted immunity can therefore lead to either immunosuppression or autoimmunity depending upon the type of innate effector dominating during the infection

    Discrimination of conventional and organic white cabbage from a long-term field trial study using untargeted LC-MS-based metabolomics

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    The influence of organic and conventional farming practices on the content of single nutrients in plants is disputed in the scientific literature. Here, large-scale untargeted LC-MS-based metabolomics was used to compare the composition of white cabbage from organic and conventional agriculture, measuring 1,600 compounds. Cabbage was sampled in 2 years from one conventional and two organic farming systems in a rigidly controlled long-term field trial in Denmark. Using Orthogonal Projection to Latent Structures-Discriminant Analysis (OPLS-DA), we found that the production system leaves a significant (p = 0.013) imprint in the white cabbage metabolome that is retained between production years. We externally validated this finding by predicting the production system of samples from one year using a classification model built on samples from the other year, with a correct classification in 83% of cases. Thus, it was concluded that the investigated conventional and organic management practices have a systematic impact on the metabolome of white cabbage. This emphasizes the potential of untargeted metabolomics for authenticity testing of organic plant products

    Neuropsychological assessment of attention in children with spina bifida

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    <p>Abstract</p> <p>Background</p> <p>Children with the severe form of spina bifida (SBM: spina bifida with myelomeningocele with accompanying hydrocephalus) may manifest attention deficits, and have a similar psychological profile to children with hydrocephalus due to other etiologies. It is unclear to what extent tests to assess attention in SBM are confounded by the accompanying cognitive or visual-motor impairments. The aim of this study was to analyse attention functions by administering two different types of attention tests, one with high and the other with low cognitive and motor requirements. This enabled the possible interaction between attention and cognitive and motor impairment to be assessed.</p> <p>Methods</p> <p>The study group comprised 31 children with SBM with shunted hydrocephalus. Twenty children with SB-only formed a closely matched comparison group. Of these, 19 children with SBM and 18 with SB had a full-scale IQ (FSIQ) higher than 70. All had undergone spinal surgery and all children with SBM had been shunted within the first months of life. Between 6 and 15 years of age, the children were assessed on focused and sustained attention, encoding, and distractibility/impulsivity, using both traditional tests and computerized attention tests.</p> <p>Results</p> <p>Compared to the SB group, attention scores of children with SBM were lower on the traditional tests, but when interfering cognitive and visual-motor requirements were eliminated using the computerised tasks, most differences disappeared. Furthermore, in contrast to traditional attention tasks, computerized tests showed no significant correlations with IQ-scores and visual-motor skills.</p> <p>Conclusion</p> <p>Assessment of attention functions in children with SBM by traditional tests may be misleading, because this paediatric population with complex cerebral malformations has difficulty with the cognitive and visual-motor requirements. To control for these interactions, the use of both traditional and computerized attention tests is recommended.</p

    The deuteron: structure and form factors

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    A brief review of the history of the discovery of the deuteron in provided. The current status of both experiment and theory for the elastic electron scattering is then presented.Comment: 80 pages, 33 figures, submited to Advances in Nuclear Physic

    Magnetism, FeS colloids, and Origins of Life

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    A number of features of living systems: reversible interactions and weak bonds underlying motor-dynamics; gel-sol transitions; cellular connected fractal organization; asymmetry in interactions and organization; quantum coherent phenomena; to name some, can have a natural accounting via physicalphysical interactions, which we therefore seek to incorporate by expanding the horizons of `chemistry-only' approaches to the origins of life. It is suggested that the magnetic 'face' of the minerals from the inorganic world, recognized to have played a pivotal role in initiating Life, may throw light on some of these issues. A magnetic environment in the form of rocks in the Hadean Ocean could have enabled the accretion and therefore an ordered confinement of super-paramagnetic colloids within a structured phase. A moderate H-field can help magnetic nano-particles to not only overcome thermal fluctuations but also harness them. Such controlled dynamics brings in the possibility of accessing quantum effects, which together with frustrations in magnetic ordering and hysteresis (a natural mechanism for a primitive memory) could throw light on the birth of biological information which, as Abel argues, requires a combination of order and complexity. This scenario gains strength from observations of scale-free framboidal forms of the greigite mineral, with a magnetic basis of assembly. And greigite's metabolic potential plays a key role in the mound scenario of Russell and coworkers-an expansion of which is suggested for including magnetism.Comment: 42 pages, 5 figures, to be published in A.R. Memorial volume, Ed Krishnaswami Alladi, Springer 201

    Intensity-modulated radiotherapy of nasopharyngeal carcinoma: a comparative treatment planning study of photons and protons

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    <p>Abstract</p> <p>Background</p> <p>The aim of this treatment planning study was to investigate the potential advantages of intensity-modulated (IM) proton therapy (IMPT) compared with IM photon therapy (IMRT) in nasopharyngeal carcinoma (NPC).</p> <p>Methods</p> <p>Eight NPC patients were chosen. The dose prescriptions in cobalt Gray equivalent (Gy<sub>E</sub>) for gross tumor volumes of the primary tumor (GTV-T), planning target volumes of GTV-T and metastatic (PTV-TN) and elective (PTV-N) lymph node stations were 72.6 Gy<sub>E</sub>, 66 Gy<sub>E</sub>, and 52.8 Gy<sub>E</sub>, respectively. For each patient, nine coplanar fields IMRT with step-and-shoot technique and 3D spot-scanned three coplanar fields IMPT plans were prepared. Both modalities were planned in 33 fractions to be delivered with a simultaneous integrated boost technique. All plans were prepared and optimized by using the research version of the inverse treatment planning system KonRad (DKFZ, Heidelberg).</p> <p>Results</p> <p>Both treatment techniques were equal in terms of averaged mean dose to target volumes. IMPT plans significantly improved the tumor coverage and conformation (<it>P </it>< 0.05) and they reduced the averaged mean dose to several organs at risk (OARs) by a factor of 2–3. The low-to-medium dose volumes (0.33–13.2 Gy<sub>E</sub>) were more than doubled by IMRT plans.</p> <p>Conclusion</p> <p>In radiotherapy of NPC patients, three-field IMPT has greater potential than nine-field IMRT with respect to tumor coverage and reduction of the integral dose to OARs and non-specific normal tissues. The practicality of IMPT in NPC deserves further exploration when this technique becomes available on wider clinical scale.</p
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