542 research outputs found

    Effect of orthophosphate on the transaldolase reaction.

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    In previous studies' with a dialyzed supernatant fraction from rat liver it was observed that the formation of heptulose phosphate from fructose g-phosphate was significantly inhibited by inorganic phosphate. It has since been shown (1, 2) that the activity of the dialyzed liver fraction can be related to its content of transketolase and transaldolase and it became of interest to determine whether the inhibition of the over-all process by phosphate was due to its effect on one or both of the enzymes involved in this process. Preliminary experiments indicated that both transketolase and transaldolase were inhibited by inorganic phosphate when the enzymes were tested in the usual assay procedures. The effect of phosphate on transaldolase is reported in the present paper

    Skeletal muscle contraction. The thorough definition of the contractile event requires both load acceleration and load mass to be known

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    <p>Abstract</p> <p>Background</p> <p>The scope of this work is to show that the correct and complete definition of the system of muscle contraction requires the knowledge of both the mass and the acceleration of the load.</p> <p>Results</p> <p>The aim is achieved by making use of a model of muscle contraction that operates into two phases. The first phase considers the effects of the power stroke in the absence of any hindrance. In the second phase viscous hindrance is introduced to match the experimental speed and yield of the contraction. It is shown that, at constant force of the load, changing load acceleration changes the time course of the pre-steady state of myofibril contraction. The decrease of the acceleration of the load from 9.8 m.s<sup>-2 </sup>to 1 m.s<sup>-2 </sup>increases the time length of the pre-steady state of the contraction from a few microseconds to many hundreds of microseconds and decreases the stiffness of the active fibre.</p> <p>Conclusions</p> <p>We urge that in the study of muscle contraction both the mass and the acceleration of the load are specified.</p

    The FXR agonist obeticholic acid inhibits the cancerogenic potential of human cholangiocarcinoma

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    Cholangiocarcinoma (CCA) is an aggressive cancer with high resistance to chemotherapeutics. CCA is enriched in cancer stem cells, which correlate with aggressiveness and prognosis. FXR, a member of the metabolic nuclear receptor family, is markedly down-regulated in human CCA. Our aim was to evaluate, in primary cultures of human intrahepatic CCA (iCCA), the effects of the FXR agonist obeticholic acid (OCA), a semisynthetic bile acid derivative, on their cancerogenic potential. Primary human iCCA cell cultures were prepared from surgical specimens of mucinous or mixed iCCA subtypes. Increasing concentrations (0–2.5 μM) of OCA were added to culture media and, after 3–10 days, effects on proliferation (MTS assay, cell population doubling time), apoptosis (annexin V-FITC/propidium iodide), cell migration and invasion (wound healing response and Matrigel invasion assay), and cancerogenic potential (spheroid formation, clonogenic assay, colony formation capacity) were evaluated. Results: FXR gene expression was downregulated (RT-qPCR) in iCCA cells vs normal human biliary tree stem cells (p < 0.05) and in mucinous iCCA vs mixed iCCA cells (p < 0.05) but was upregulated by addition of OCA. OCA significantly (p < 0.05) inhibited proliferation of both mucinous and mixed iCCA cells, starting at a concentration as low as 0.05 μM. Also, CDCA (but not UDCA) inhibited cell proliferation, although to a much lower extent than OCA, consistent with its different affinity for FXR. OCA significantly induced apoptosis of both iCCA subtypes and decreased their in vitro cancerogenic potential, as evaluated by impairment of colony and spheroid formation capacity and delayed wound healing and Matrigel invasion. In general, these effects were more evident in mixed than mucinous iCCA cells. When tested together with Gemcitabine and Cisplatin, OCA potentiated the anti-proliferative and pro-apoptotic effects of these chemotherapeutics, but mainly in mixed iCCA cells. OCA abolished the capacity of both mucinous and mixed iCCA cells to form colonies when administered together with Gemcitabine and Cisplatin. In subcutaneous xenografts of mixed iCCA cells, OCA alone or combined with Gemcitabine or Cisplatin markedly reduced the tumor size after 5 weeks of treatment by inducing necrosis of tumor mass and inhibiting cell proliferation. In conclusion, FXR is down-regulated in iCCA cells, and its activation by OCA results in anti-cancerogenic effects against mucinous and mixed iCCA cells, both in vitro and in vivo. The effects of OCA predominated in mixed iCCA cells, consistent with the lower aggressiveness and the higher FXR expression in this CCA subtype. These results, showing the FXR-mediated capacity of OCA to inhibit cholangiocarcinogenesis, represent the basis for testing OCA in clinical trials of CCA patients

    Molecular charcteristics of chicken kidney arginase

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    Interrogating colorectal cancer metastasis to liver: a search for clinically viable compounds and mechanistic insights in colorectal cancer Patient Derived Organoids

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    Approximately 20-50% of patients presenting with localized colorectal cancer progress to stage IV metastatic disease (mCRC) following initial treatment and this is a major prognostic determinant. Here, we have interrogated a heterogeneous set of primary colorectal cancer (CRC), liver CRC metastases and adjacent liver tissue to identify molecular determinants of the colon to liver spreading. Screening Food and Drug Administration (FDA) approved drugs for their ability to interfere with an identified colon to liver metastasis signature may help filling an unmet therapeutic need

    The social cost of chronic kidney disease in Italy

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    This study aims to estimate the mean annual social cost per patient with chronic kidney disease (CKD) by stages 4 and 5 pre-dialyses and cost components in Italy. The multicenter cross-sectional study included all adult outpatients in charge of the 14 main Nephrology Centers of Tuscany Region during 7 weeks from 2012 to 2013. Direct medical costs have been estimated using tariffs for laboratory tests, diagnostic exams, visits, hospitalization and prices for drugs. Non-medical costs included expenses of low-protein special foods, travel, and formal and informal care. Patients' and caregivers' losses of productivity have been estimated as indirect costs using the human capital approach. Costs have been expressed in Euros (2016). Totals of 279 patients in stage 4 and 205 patients in stage 5 have been enrolled. The estimated mean annual social cost of a patient with CKD were a,notsign7422 (+/- a,notsign6255) for stage 4 and a,notsign8971 (+/- a,notsign6503) for stage 5 (p &lt; 0.05). Direct medical costs were higher in stage 5 as compared to stage 4; direct non-medical costs and indirect costs accounted, respectively, for 41 and 5 % of the total social cost of CKD stage 4 and for 33 and 9 % of CKD stage 5. In Italy, the overall annual social cost of CKD was a,notsign1,809,552,398 representing 0.11 % of the Gross Domestic Product. Direct non-medical costs and indirect costs were weighted on the social cost of CKD almost as much as the direct medical cost. Patients, their families and the productivity system sustain the burden of the disease almost as much as the healthcare system. © 2016, The Author(s)

    An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

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    For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
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