1,881 research outputs found

    A cell-based reglucosylation assay demonstrates the role of GT1 in the quality control of a maturing glycoprotein

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    The endoplasmic reticulum (ER) protein GT1 (UDP-glucose: glycoprotein glucosyltransferase) is the central enzyme that modifies N-linked carbohydrates based upon the properties of the polypeptide backbone of the maturing substrate. GT1 adds glucose residues to nonglucosylated proteins that fail the quality control test, supporting ER retention through persistent binding to the lectin chaperones calnexin and calreticulin. How GT1 functions in its native environment on a maturing substrate is poorly understood. We analyzed the reglucosylation of a maturing model glycoprotein, influenza hemagglutinin (HA), in the intact mammalian ER. GT1 reglucosylated N-linked glycans in the slow-folding stem domain of HA once the nascent chain was released from the ribosome. Maturation mutants that disrupted the oxidation or oligomerization of HA also supported region-specific reglucosylation by GT1. Therefore, GT1 acts as an ER quality control sensor by posttranslationally reglucosylating glycans on slow-folding or nonnative domains to recruit chaperones specifically to critical aberrant regions

    Wind characteristics over complex terrain: laboratory simulation and field measurements at Rakaia Gorge, New Zealand: final report, part II

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    CER77-78RNM29.Prepared for the United States Department of Energy, Division of Solar Technology, Federal Wind Energy Program.DOE contract no. EY-76-S06-2438, A001.Includes bibliographical references (pages 93-102).May 1978

    Plasma plume effects on the conductivity of amorphous-LaAlO<sub>3</sub>/SrTiO<sub>3</sub> interfaces grown by pulsed laser deposition in O<sub>2</sub> and Ar

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    Amorphous LaAlO3/SrTiO3 interfaces exhibit metallic conductivity similarto those found for the extensively studied crystalline-LaAlO3/SrTiO3 interfaces. Here, we investigate the conductivity of the amorphous-LaAlO3/SrTiO3 interfaces grown in different pressures of O2 and Ar background gases. During the deposition, the LaAlO3 ablation plume is also studied, in situ, by fast photography and space-resolved optical emission spectroscopy. An interesting correlation between interfacial conductivity and kinetic energy of the Al atoms in the plume is observed: to assure conducting interfaces of amorphous-LaAlO3/SrTiO3, the kinetic energy of Al should be higher than 1 eV. Our findings add further insights on mechanisms leading to interfacial conductivity in SrTiO3-based oxide heterostructures

    Randomized controlled trial of intraoperative goal-directed fluid therapy in aerobically fit and unfit patients having major colorectal surgery.

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    BACKGROUND: Intraoperative fluid therapy regimens using oesophageal Doppler monitoring (ODM) to optimize stroke volume (SV) (goal-directed fluid therapy, GDT) have been associated with a reduction in length of stay (LOS) and complication rates after major surgery. We hypothesized that intraoperative GDT would reduce the time to surgical readiness for discharge (RfD) of patients having major elective colorectal surgery but that this effect might be less marked in aerobically fit patients. METHODS: In this double-blinded controlled trial, 179 patients undergoing major open or laparoscopic colorectal surgery were characterized as aerobically 'fit' (n=123) or 'unfit' (n=56) on the basis of their performance during a cardiopulmonary exercise test. Within these fitness strata, patients were randomized to receive a standard fluid regimen with or without ODM-guided intraoperative GDT. RESULTS: GDT patients received an average of 1360 ml of additional intraoperative colloid. The mean cardiac index and SV at skin closure were significantly higher in the GDT group than in controls. Times to RfD and LOS were longer in GDT than control patients but did not reach statistical significance (median 6.8 vs 4.9 days, P=0.09, and median 8.8 vs 6.7 days, P=0.09, respectively). Fit GDT patients had an increased RfD (median 7.0 vs 4.7 days; P=0.01) and LOS (median 8.8 vs 6.0 days; P=0.01) compared with controls. CONCLUSIONS: Intraoperative SV optimization conferred no additional benefit over standard fluid therapy. In an aerobically fit subgroup of patients, GDT was associated with detrimental effects on the primary outcome. TRIAL REGISTRY: UK NIHR CRN 7285, ISRCTN 14680495. http://public.ukcrn.org.uk/Search/StudyDetail.aspx?StudyID=7285

    Autologous Stem Cell Transplant is Feasible in Very Elderly Patients with Lymphoma and Limited Comorbidity

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    In patients with recurrent Hodgkin or non-Hodgkin\u27s lymphoma, autologous stem cell transplantation (ASCT) can offer potential for cure or long-term remission. Because of potential toxicity, elderly patients are usually not considered candidates, but data regarding tolerability and efficacy in this group are lacking. The transplant database at Weill Cornell Medical College was reviewed to identify patients with lymphoma undergoing ASCT at age 69 or greater. Clinical data and comorbidities were correlated with outcome. Twenty-one patients were identified. Sixteen of 19 evaluable patients (76%) achieved complete remission following ASCT, while 2 patients died before response assessment. Median progression-free survival following ASCT was 8 months and median overall survival was 18 months. Age was not predictive of overall survival, but patients 75 and older had inferior progression-free survival compared to younger patients. High-risk status by hematopoietic stem cell transplant comorbidity index (HCT-CI) was associated with short overall survival and high transplant-related mortality. ASCT is feasible and of potential benefit in selected elderly lymphoma patients. Consideration of comorbidities, rather than age alone, may allow selection of patients likely to tolerate and benefit from ASCT

    Autologous Stem Cell Transplant is Feasible in Very Elderly Patients with Lymphoma and Limited Comorbidity

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    In patients with recurrent Hodgkin or non-Hodgkin\u27s lymphoma, autologous stem cell transplantation (ASCT) can offer potential for cure or long-term remission. Because of potential toxicity, elderly patients are usually not considered candidates, but data regarding tolerability and efficacy in this group are lacking. The transplant database at Weill Cornell Medical College was reviewed to identify patients with lymphoma undergoing ASCT at age 69 or greater. Clinical data and comorbidities were correlated with outcome. Twenty-one patients were identified. Sixteen of 19 evaluable patients (76%) achieved complete remission following ASCT, while 2 patients died before response assessment. Median progression-free survival following ASCT was 8 months and median overall survival was 18 months. Age was not predictive of overall survival, but patients 75 and older had inferior progression-free survival compared to younger patients. High-risk status by hematopoietic stem cell transplant comorbidity index (HCT-CI) was associated with short overall survival and high transplant-related mortality. ASCT is feasible and of potential benefit in selected elderly lymphoma patients. Consideration of comorbidities, rather than age alone, may allow selection of patients likely to tolerate and benefit from ASCT

    Testing the theory of immune selection in cancers that break the rules of transplantation

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    Modification of cancer cells likely to reduce their immunogenicity, including loss or down-regulation of MHC molecules, is now well documented and has become the main support for the concept of immune surveillance. The evidence that these modifications, in fact, result from selection by the immune system is less clear, since the possibility that they may result from reorganized metabolism associated with proliferation or from cell de-differentiation remains. Here, we (a) survey old and new transplantation experiments that test the possibility of selection and (b) survey how transmissible tumours of dogs and Tasmanian devils provide naturally evolved tests of immune surveillance
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