397 research outputs found

    Reduction of brain metastases in plasminogen activator inhibitor-1-deficient mice with transgenic ocular tumors

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    Plasminogen activator inhibitor-1 is known to play a paradoxical positive role in tumor angiogenesis, but its contribution to metastatic spread remains unclear. We studied the impact of plasminogen activator inhibitor (PAI)-1 deficiency in a transgenic mouse model of ocular tumors originating from retinal epithelial cells and leading to brain metastasis (TRP-1/SV40 Tag mice). PAI-1 deficiency did not affect primary tumor growth or vascularization, but was associated with a smaller number of brain metastases. Brain metastases were found to be differentially distributed between the two genotypes. PAI-1-deficient mice displayed mostly secondary foci expanding from local optic nerve infiltration, whereas wild-type animals displayed more disseminated nodules in the scissura and meningeal spaces. SuperArray GEarray analyses aimed at detecting molecules potentially compensating for PAI-1 deficiency demonstrated an increase in fibroblast growth factor-1 (FGF-1) gene expression in primary tumors, which was confirmed by reverse transcription-polymerase chain reaction and western blotting. Our data provide the first evidence of a key role for PAI-1 in a spontaneous model of metastasis and suggest that angiogenic factors, such as FGF-1, may be important for primary tumor growth and may compensate for the absence of PAI-1. They identify PAI-1 and FGF-1 as important targets for combined antitumor strategie

    Three cases of severe subfulminant hepatitis in heart-transplanted patients after nosocomial transmission of a mutant hepatitis B virus

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    Fulminant and severe viral hepatitis are frequently associated with mutant hepatitis B virus (HBV) strains. In this study, the genetic background of a viral strain causing severe subfulminant outcome in heart-transplanted patients was studied and compared with viral hepatitis B strains that were not linked to severe liver disease in the same setting. A total of 46 patients infected nosocomially with HBV genotype A were studied. Five different viral strains were detected, infecting 3, 9, 5, 24, and 5 patients, respectively. Only one viral strain was found to be associated with the subfulminant outcome and 3 patient deaths as a consequence of severe liver disease. The remaining 43 patients with posttransplantation HBV infection did not show this fatal outcome. Instead, symptoms of hepatitis were generally mild or clinically undiagnosed. Comparison of this virus genome with the four other strains showed an accumulation of mutations in the basic core promoter, a region that influences viral replication, but also in hepatitis B X protein (HBX) (7 mutant motifs), core (10 mutant motifs), the preS1 region (5 mutant motifs), and the HBpolymerase open reading frame (17 motifs). Some of these variations, such as those in the core region, were located on the tip of the protruding spike of the viral capsid (codons 60 to 90), also known in part as an important HLA class II-restricted epitope region. These mutations might therefore influence the immune-mediated response. The viral strain causing subfulminant hepatitis was, in addition, the only strain with a preCore stop codon mutation and, thus, hepatitis B e antigen (HBeAg) expression was never observed. The combination of these specific viral factors is thought to be responsible for the fatal outcome in these immune-suppressed heart-transplant recipients

    Orthotopic liver transplantation for acute and subacute hepatic failure in adults

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    The role of liver transplantation in 29 patients with fulminant and subacute hepatic failure due to a variety of different causes was examined by comparing the outcome and a variety of “hospitalization” variables. Transplanted patients (n = 13) were more likely to survive (p < 0.05), were younger (p < 0.05) and spent more time in the hospital (p < 0.025) than did those who were not transplanted (n = 16). Despite spending a much longer time in the hospital, transplanted patients spent less time in the intensive care unit (p < 0.05) in coma (p < 0.01) and on a respirator (p < 0.01) than did those not transplanted. Most importantly, the survival rate for transplanted patients was significantly improved (p < 0.05) as compared to those not transplanted. We conclude that liver transplantation can be applied successfully to the difficult clinical problem of fulminant and subacute hepatic failure. Copyright © 1987 American Association for the Study of Liver Disease

    Improving product availability in hospitals : the role of inventory inaccuracies

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Engineering Systems Division, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references (p. [184]-193).All players in the healthcare industry face increasing public and political pressure to improve quality of care and control costs. Hospitals, on the frontline of this challenge, face nursing shortages and financial constraints. Survey data indicate that missing medication and supplies interrupt nurses more than twice per shift, increasing costs and putting patients at risk. These challenges persist even though over 72% of U.S. hospitals have deployed Automated Dispensing Machines (ADMs), electronic cabinets that automate inventory management processes and improve product availability. This research investigates the role of inventory inaccuracies, i.e., mismatches between book inventory and physical inventory on hand, as drivers of product availability in hospitals. The research objectives are three-fold: (1) characterize the sources of inventory inaccuracies prevalent in a hospital context; (2) quantify the impact of inventory inaccuracies on product availability and performance metrics; and (3) identify and evaluate practical strategies that hospitals can use to improve product availability by reducing and mitigating inventory inaccuracies. This thesis views the hospital supply chain as a socio-technical system and addresses the research questions using a multilevel, multi-method approach. The research is empirically grounded by the case study of Lambda, a New England area hospital that provided qualitative and high-frequency transactional data from its network of 108 ADMs that stock over 21,000 product-location combinations. First, by classifying sources of inventory inaccuracies this thesis identifies Imperfect Demand Recording as a hospital-specific source of such inaccuracies. Recording Accuracy is proposed as a metric of user behavior at product and location levels, and reveals that between five and thirty percent of product usage is not recorded. Then, a single-product Discrete-Event Simulation (DES) model shows that Imperfect Demand Recording causes large reductions in availability unless mitigated by frequent and consistent (i.e., equally-spaced) inventory counts, and that service level estimates provided by ADMs can have a large, optimistic bias. Assuming that count timing is independent of inventory state, an analytical model provides a closed-form generalization of the simulation results and shows that variability in cycle count has a nonlinear and substantial effect, causing 35% of counts performed at Lambda to be ineffective. Finally, a sequential and iterative framework integrating the managerial implications of these contributions is proposed.by David C. Opolon.Ph.D

    In vivo study of the GC90/IRIV vaccine for immune response and autoimmunity into a novel humanised transgenic mouse

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    Parathyroid hormone-related protein (PTH-rP), a secreted protein produced by prostate carcinoma and other epithelial cancers, is considered a key agent for the development of bone metastases. We investigated the construct GC90/IRIV, composed of immunopotentiating reconstituted influenza virosomes (IRIV) containing PTH-rP gene plasmids (GC90), as a potential tool for human anticancer immunotherapy into humanised mice transgenic for HLA-A(*)02.01, the human-β2 microglobulin, and the human CD8α molecule. Intranasal administration of GC90/IRIV resulted in the induction of a PTH-rP-specific multiepitope cytotoxic T-cell (CTL) response. Cytotoxic T cells derived from vaccinated mice were capable of lysing in vitro syngenic murine PTH-rP transfectants and human HLA-A(*)02.01+/PTH-rP+ prostate carcinoma LNCaP cells as well. The immune response capacity and the absence of any sign of toxicity and/or autoimmunity in vivo suggest the GC90/IRIV vaccine as a valid tool for active specific immunotherapy of human cancers and metastases overexpressing PTH-rP

    Potentiation of radiation therapy by the oncolytic adenovirus dl1520 (ONYX-015) in human malignant glioma xenografts

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    In spite of aggressive surgery, irradiation and/or chemotherapy, treatment of malignant gliomas remains a major challenge in adults and children due to high treatment failure. We have demonstrated significant cell lysis and antitumour activity of the E1B-55 kDa-gene-deleted adenovirus ONYX-015 (dl1520, CI-1042; ONYX Pharmaceuticals) in subcutaneous human malignant glioma xenografts deriving from primary tumours. Here, we show the combined efficacy of this oncolytic therapy with radiation therapy. Total body irradiation (5 Gy) of athymic nude mice prior to intratumoral injections of ONYX-015 1 x 10(8) PFU daily for 5 consecutive days yielded additive tumour growth delays in the p53 mutant xenograft IGRG88. Radiation therapy was potentiated in the p53 functional tumour IGRG121 with a 'subtherapeutic' dose of 1 x 10(7) PFU daily for 5 consecutive days, inducing significant tumour growth delay, 90% tumour regression and 50% tumour-free survivors 4 months after treatment. These potentiating effects were not due to increased adenoviral infectivity or replication. Furthermore, cell lysis and induction of apoptosis, the major mechanisms for adenoviral antitumour activity, did not play a major role in the combined treatment strategy. Interestingly, the oncolytic adenovirus seemed to accelerate radiation-induced tumour fibrosis. Potentiating antitumour activity suggests the development of this combined treatment for these highly malignant tumours

    Treatment of hepatic encephalopathy by on-line hemodiafiltration: a case series study

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    <p>Abstract</p> <p>Background</p> <p>It is thought that a good survival rate of patients with acute liver failure can be achieved by establishing an artificial liver support system that reliably compensates liver function until the liver regenerates or a patient undergoes transplantation. We introduced a new artificial liver support system, on-line hemodiafiltration, in patients with acute liver failure.</p> <p>Methods</p> <p>This case series study was conducted from May 2001 to October 2008 at the medical intensive care unit of a tertiary care academic medical center. Seventeen consecutive patients who admitted to our hospital presenting with acute liver failure were treated with artificial liver support including daily on-line hemodiafiltration and plasma exchange.</p> <p>Results</p> <p>After 4.9 ± 0.7 (mean ± SD) on-line hemodiafiltration sessions, 16 of 17 (94.1%) patients completely recovered from hepatic encephalopathy and maintained consciousness for 16.4 ± 3.4 (7-55) days until discontinuation of artificial liver support (a total of 14.4 ± 2.6 [6-47] on-line hemodiafiltration sessions). Significant correlation was observed between the degree of encephalopathy and number of sessions of on-line HDF required for recovery of consciousness. Of the 16 patients who recovered consciousness, 7 fully recovered and returned to society with no cognitive sequelae, 3 died of complications of acute liver failure except brain edema, and the remaining 6 were candidates for liver transplantation; 2 of them received living-related liver transplantation but 4 died without transplantation after discontinuation of therapy.</p> <p>Conclusions</p> <p>On-line hemodiafiltration was effective in patients with acute liver failure, and consciousness was maintained for the duration of artificial liver support, even in those in whom it was considered that hepatic function was completely abolished.</p
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