111 resultados para FAILURE ANALYSIS
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BACKGROUND: Tyrosine kinase inhibitors (TKI) improve the outcome of patients with advanced gastrointestinal stromal tumour (GIST), but treatment failure is frequent, and prognosis then bleak. Smaller trials in this setting suggested activity for sorafenib, a multikinase inhibitor of receptor tyrosine kinases and RAF serine/threonine kinases. PATIENTS AND METHODS: We retrospectively evaluated the efficacy of sorafenib, starting dose 400mg twice daily, in a large community-based cohort of 124 patients treated in 12 European and one United States (U.S.) cancer centre. All but one patient had a WHO performance score 0-2. All had failed both imatinib and sunitinib, 68 patients nilotinib and 26 had failed investigational therapy, too. RESULTS: Twelve (10%) patients responded to sorafenib and 70 (57%) patients achieved disease stabilisation. Sorafenib was moderately tolerated, and toxicity reported in 56% of the patients. Rash, hand-foot-syndrome and diarrhea occurred frequently. Sorafenib dosage was reduced in a third of patients, but this did not have an impact on progression-free survival (PFS) (p=0.15). Median PFS was 6.4months (95% confidence interval [CI], 4.6-8.0months) and median overall survival (OS) 13.5months (95% CI, 10.0-21.0months). Patients with a good performance status and those who responded to sorafenib had a significant better PFS. CONCLUSION: We conclude that sorafenib is active in GIST resistant to imatinib, sunitinib and nilotinib. These results warrant further investigation of sorafenib or similar molecules in GIST.
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We present the application of terrestrial laser scanning (TLS) for the monitoring and characterization of an active landslide area in Val Canaria (Ticino, Southern Swiss Alps). At catchment scale, the study area is affected by a large Deep Seated Gravitational Slope Deformation (DSGSD) area presenting, in the lower boundary, several retrogressive landslides active since the 1990s. Due to its frequent landslide events this area was periodically monitored by TLS since 2006. Periodic acquisitions provided new information on 3D displacements at the bottom of slope and the detection of centimetre to decimetre level scale changes (e.g. rockfall and pre-failure deformations). In October 2009, a major slope collapse occured at the bottom of the most unstable area. Based on the comparison between TLS data before and after the collapse, we carried out a detailed failure mechanism analysis and volume calculation.
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OBJECTIVE: To investigate whether HIV-infected patients on a stable and fully suppressive combination antiretroviral therapy (cART) regimen could safely be monitored less often than the current recommendations of every 3 months. DESIGN: Two thousand two hundred and forty patients from the EuroSIDA study who maintained a stable and fully suppressed cART regimen for 1 year were included in the analysis. METHODS: Risk of treatment failure, defined by viral rebound, fall in CD4 cell count, development of new AIDS-defining illness, serious opportunistic infection or death, in the 12 months following a year of a stable and fully suppressed regimen was assessed. RESULTS: One hundred thirty-one (6%) patients experienced treatment failure in the 12 months following a year of stable therapy, viral rebound occurred in 99 (4.6%) patients. After 3, 6 and 12 months, patients had a 0.3% [95% confidence interval (CI) 0.1-0.5], 2.2% (95% CI 1.6-2.8) and 6.0% (95% CI 5.0-7.0) risk of treatment failure, respectively. Patients who spent more than 80% of their time on cART with fully suppressed viraemia prior to baseline had a 38% reduced risk of treatment failure, hazard ratio 0.62 (95% CI 0.42-0.90, P = 0.01). CONCLUSION: Patients who have responded well to cART and are on a well tolerated and durably fully suppressive cART regimen have a low chance of experiencing treatment failure in the next 3-6 months. Therefore, in this subgroup of otherwise healthy patients, it maybe reasonable to extend visit intervals to 6 months, with cost and time savings to both the treating clinics and the patients.
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Large slope failures in fractured rocks are often controlled by the combination of pre-existing tectonic fracturing and brittle failure propagation in the intact rock mass during the pre-failure phase. This study focuses on the influence of fold-related fractures and of post-folding fractures on slope instabilities with emphasis on Turtle Mountain, located in SW Alberta (Canada). The structural features of Turtle Mountain, especially to the south of the 1903 Frank Slide, were investigated using a high-resolution digital elevation model combined with a detailed field survey. These investigations allowed the identification of six main discontinuity sets influencing the slope instability and surface morphology. According to the different deformation phases affecting the area, the potential origin of the detected fractures was assessed. Three discontinuity sets are correlated with the folding phase and the others with post-folding movements. In order to characterize the rock mass quality in the different portions of the Turtle Mountain anticline, the geological strength index (GSI) has been estimated. The GSI results show a decrease in rock mass quality approaching the fold hinge area due to higher fracture persistence and higher weathering. These observations allow us to propose a model for the potential failure mechanisms related to fold structures.
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Turtle Mountain in Alberta, Canada has become an important field laboratory for testing different techniques related to the characterization and monitoring of large slope mass movements as the stability of large portions of the eastern face of the mountain is still questionable. In order to better quantify the volumes potentially unstable and the most probable failure mechanisms and potential consequences, structural analysis and runout modeling were preformed. The structural features of the eastern face were investigated using a high resolution digital elevation model (HRDEM). According to displacement datasets and structural observations, potential failure mechanisms affecting different portions of the mountain have been assessed. The volumes of the different potentially unstable blocks have been calculated using the Sloping Local Base Level (SLBL) method. Based on the volume estimation, two and three dimensional dynamic runout analyses have been performed. Calibration of this analysis is based on the experience from the adjacent Frank Slide and other similar rock avalanches. The results will be used to improve the contingency plans within the hazard area.
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BACKGROUND: We conducted a retrospective analysis of administration of nonoccupational HIV post-exposure prophylaxis (nPEP) in a single centre where tracing and testing of the source of exposure were carried out systematically over a 10-year period. METHODS: Files of all nPEP requests between 1998 and 2007 were reviewed. Characteristics of the exposed and source patients, the type of exposure, and clinical and serological outcomes were analysed. RESULTS: nPEP requests increased by 850% over 10 years. Among 910 events, 58% were heterosexual exposures, 15% homosexual exposures, 6% sexual assaults and 20% nonsexual exposures. In 208 events (23%), the source was reported to be HIV positive. In the remaining cases, active source tracing enabled 298 HIV tests to be performed (42%) and identified 11 HIV infections (3.7%). nPEP was able to be avoided or interrupted in 31% of 910 events when the source tested negative. Of 710 patients who started nPEP, 396 (56%) reported side effects, among whom 39 (5%) had to interrupt treatment. There were two HIV seroconversions, and neither was attributed to nPEP failure. CONCLUSIONS: nPEP requests increased over time. HIV testing of the source person avoided nPEP in 31% of events and was therefore paramount in the management of potential HIV exposures. Furthermore, it allowed active screening of populations potentially at risk for undiagnosed HIV infection, as shown by the increased HIV prevalence in these groups (3.7%) compared with a prevalence of 0.3% in Switzerland as a whole.
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We conducted this study to determine the relative influence of various mechanical and patient-related factors on the incidence of dislocation after primary total hip asthroplasty (THA). Of 2,023 THAs, 21 patients who had at least 1 dislocation were compared with a control group of 21 patients without dislocation, matched for age, gender, pathology, and year of surgery. Implant positioning, seniority of the surgeon, American Society of Anesthesiologists (ASA) score, and diminished motor coordination were recorded. Data analysis included univariate and multivariate methods. The dislocation risk was 6.9 times higher if total anteversion was not between 40 degrees and 60 degrees and 10 times higher in patients with high ASA scores. Surgeons should pay attention to total anteversion (cup and stem) of THA. The ASA score should be part of the preoperative assessment of the dislocation risk.
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BACKGROUND: Determining a specific death cause may facilitate individualized therapy in patients with heart failure (HF). Cardiac resynchronization therapy (CRT) decreased mortality in the Cardiac Resynchronization in Heart Failure trial by reducing pump failure and sudden cardiac death (SCD). This study analyzes predictors of specific causes of death. METHODS AND RESULTS: Univariate and multivariate analyses used 8 baseline and 3-month post-randomization variables to predict pump failure and SCD (categorized as "definite," "probable," and "possible"). Of 255 deaths, 197 were cardiovascular. There were 71 SCDs with a risk reduction by CRT of 0.47 (95% confidence interval 0.29-0.76; P = .002) with similar reductions in SCD classified as definite, probable, and possible. Univariate SCD predictors were 3-month HF status (mitral regurgitation [MR] severity, plasma brain natriuretic peptide [BNP], end-diastolic volume, and systolic blood pressure), whereas randomization to CRT decreased risk. Multivariate SCD predictors were randomization to CRT 0.56 (0.53-0.96, P = .035) and 3-month MR severity 1.82 (1.77-2.60, P = .0012). Univariate pump failure death predictors related to baseline HF state (quality of life score, interventricular mechanical delay, end-diastolic volume, plasma BNP, MR severity, and systolic pressure), whereas randomization to CRT and nonischemic cardiomyopathy decreased risk; multivariate predictors of pump failure death were baseline plasma BNP and systolic pressure and randomization to CRT. CONCLUSION: CRT decreased SCD in patients with systolic HF and ventricular dyssynchrony. SCD risk was increased with increased severity of MR (including the 3-month value for MR as a time-dependent covariate) and reduced by randomization to CRT. HF death was increased related to the level of systolic blood pressure, log BNP, and randomization to CRT. These results emphasize the importance and interdependence of HF severity to mortality from pump failure and SCD.
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PURPOSE: Positron emission tomography with (18)F-fluorodeoxyglucose (FDG-PET) was used to evaluate treatment response in patients with gastrointestinal stromal tumors (GIST) after administration of sunitinib, a multitargeted tyrosine kinase inhibitor, after imatinib failure. PATIENTS AND METHODS: Tumor metabolism was assessed with FDG-PET before and after the first 4 weeks of sunitinib therapy in 23 patients who received one to 12 cycles of sunitinib therapy (4 weeks of 50 mg/d, 2 weeks off). Treatment response was expressed as the percent change in maximal standardized uptake values (SUV). The primary end point of time to tumor progression was compared with early PET results on the basis of traditional Response Evaluation Criteria in Solid Tumors (RECIST) criteria. RESULTS: Progression-free survival (PFS) was correlated with early FDG-PET metabolic response (P < .0001). Using -25% and +25% thresholds for SUV variations from baseline, early FDG-PET response was stratified in metabolic partial response, metabolically stable disease, or metabolically progressive disease; median PFS rates were 29, 16, and 4 weeks, respectively. Similarly, when a single FDG-PET positive/negative was considered after 4 weeks of sunitinib, the median PFS was 29 weeks for SUVs less than 8 g/mL versus 4 weeks for SUVs of 8 g/mL or greater (P < .0001). None of the patients with metabolically progressive disease subsequently responded according to RECIST criteria. Multivariate analysis showed shorter PFS in patients who had higher residual SUVs (P < .0001), primary resistance to imatinib (P = .024), or nongastric GIST (P = .002), regardless of the mutational status of the KIT and PDGFRA genes. CONCLUSION: Week 4 FDG-PET is useful for early assessment of treatment response and for the prediction of clinical outcome. Thus, it offers opportunities to individualize and optimize patient therapy.
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Linezolid is used off-label to treat multidrug-resistant tuberculosis (MDR-TB) in absence of systematic evidence. We performed a systematic review and meta-analysis on efficacy, safety and tolerability of linezolid-containing regimes based on individual data analysis. 12 studies (11 countries from three continents) reporting complete information on safety, tolerability, efficacy of linezolid-containing regimes in treating MDR-TB cases were identified based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Meta-analysis was performed using the individual data of 121 patients with a definite treatment outcome (cure, completion, death or failure). Most MDR-TB cases achieved sputum smear (86 (92.5%) out of 93) and culture (100 (93.5%) out of 107) conversion after treatment with individualised regimens containing linezolid (median (inter-quartile range) times for smear and culture conversions were 43.5 (21-90) and 61 (29-119) days, respectively) and 99 (81.8%) out of 121 patients were successfully treated. No significant differences were detected in the subgroup efficacy analysis (daily linezolid dosage ≤600 mg versus >600 mg). Adverse events were observed in 63 (58.9%) out of 107 patients, of which 54 (68.4%) out of 79 were major adverse events that included anaemia (38.1%), peripheral neuropathy (47.1%), gastro-intestinal disorders (16.7%), optic neuritis (13.2%) and thrombocytopenia (11.8%). The proportion of adverse events was significantly higher when the linezolid daily dosage exceeded 600 mg. The study results suggest an excellent efficacy but also the necessity of caution in the prescription of linezolid.
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AbstractMyotonic dystrophy type 1 (DM1), also known as Steinert's disease, is an inherited autosomal dominant disease. DM1 is characterized by myotonia, muscular weakness and atrophy, but it has a multisystemic phenotype. The genetic basis of the disease is the abnormal expansion of CTG repeats in the 3' untranslated region of the DM protein kinase (DMPK) gene on chromosome 19. The size of the expansion correlates to the severity of the disease and the age of onset.Respiratory problems have long been recognized to be a major feature of the disease and are the main factor contributing to mortality ; however the mechanisms are only partly known. The aim of our study is to investigate whether respiratory failure results only from the involvement of the dystrophic process at the level of the respiratory muscles or comes also from abnormalities in the neuronal network that generates and controls the respiratory rhythm. The generation of valid transgenic mice displaying the human DM1 phenotype by the group of Dr. Gourdon provided us a useful tool to analyze the brain stem respiratory neurons, spinal phrenic motoneurons and phrenic nerves. We examined therefore these structures in transgenic mice carrying 350-500 CTGs and displaying a mild form of the disease (DM1 mice). The morphological and morphometric analysis of diaphragm muscle sections revealed a denervation of the end-plates (EPs), characterized by a decrease in size and shape complexity of EPs and a reduction in the density of acetylcholine receptors (AChRs). Also a strong and significant reduction in the number of phrenic unmyelinated fibers was detected, but not in the myelinated fibers. In addition, no pathological changes were detected in the cervical motoneurons and medullary respiratory centers (Panaite et al., 2008). These results suggest that the breathing rhythm is probably not affected in mice expressing a mild form of DM1, but rather the transmission of action potentials at the level of diaphragm NMJs is deficient.Because size of the mutation increases over generations, new transgenic mice were obtained from the mice with 350-500 CTGs, resulting from a large increase of CTG repeat in successive generations, these mice carry more than 1300 CTGs (DMSXL) and display a severe DM1 phenotype (Gomes-Pereira et al., 2007). Before we study the mechanism underlying the respiratory failure in DMSXL mice, we analyzed the peripheral nervous system (PNS) in these mice by electrophysiological, histological and morphometric methods. Our results provide strong evidence that DMSXL mice have motor neuropathy (Panaite et al., 2010, submitted). Therefore the DMSXL mice expressing severe DM1 features represent for us a good tool to investigate, in the future, the physiological, structural and molecular alterations underlying respiratory failure in DM1. Understanding the mechanism of respiratory deficiency will help to better target the therapy of these problems in DM1 patients. In addition our results may, in the future, orientate pharmaceutical and clinical research towards possible development of therapy against respiratory deficits associated with the DM1.RésuméLa dystrophic myotonique type 1 (DM1), aussi dénommée maladie de Steinert, est une maladie héréditaire autosomique dominante. Elle est caractérisée par une myotonie, une faiblesse musculaire avec atrophie et se manifeste aussi par un phénotype multisystémique. La base génétique de la maladie est une expansion anormale de répétitions CTG dans une région non traduite en 3' du gène de la DM protéine kinase (DMPK) sur le chromosome 19. La taille de l'expansion est corrélée avec la sévérité et l'âge d'apparition de DM1.Bien que les problèmes respiratoires soient reconnus depuis longtemps comme une complication de la maladie et soient le principal facteur contribuant à la mortalité, les mécanismes en sont partiellement connus. Le but de notre étude est d'examiner si l'insuffisance respiratoire de la DM1 est dû au processus dystrophique au niveau des muscles respiratoires ou si elle est entraînée aussi par des anomalies dans le réseau neuronal qui génère et contrôle le rythme respiratoire. La production par le groupe du Dr. Gourdon de souris transgéniques de DM1, manifestant le phénotype de DM1 humaine, nous a fourni un outil pour analyser les nerfs phréniques, les neurones des centres respiratoires du tronc cérébral et les motoneurones phréniques. Par conséquence, nous avons examiné ces structures chez des souris transgéniques portant 350-500 CTG et affichant une forme légère de la maladie (souris DM1). L'analyse morphologique et morphométrique des sections du diaphragme a révélé une dénervation des plaques motrices et une diminution de la taille et de la complexité de la membrane postsynaptîque, ainsi qu'une réduction de la densité des récepteurs à l'acétylcholine. Nous avons aussi détecté une réduction significative du nombre de fibres nerveuses non myélinisées mais pas des fibres myélinisées. Par ailleurs, aucun changement pathologique n'a été détecté pour les neurones moteurs médullaires cervicaux et centres respiratoires du tronc cérébral (Panaite et al., 2008). Ces résultats suggèrent que le iythme respiratoire n'est probablement pas affecté chez les souris manifestant une forme légère du DM1, mais plutôt que la transmission des potentiels d'action au niveau des plaques motrices du diaphragme est déficiente.Comme la taille du mutation augmente au fil des générations, de nouvelles souris transgéniques ont été générés par le groupe Gourdon; ces souris ont plus de 1300 CTG (DMSXL) et manifestent un phénotype sévère du DM1 (Gomes-Pereira et al., 2007). Avant d'étudier le mécanisme sous-jacent de l'insuffisance respiratoire chez les souris DMSXL, nous avons analysé le système nerveux périphérique chez ces souris par des méthodes électrophysiologiques, histologiques et morphométriques. Nos résultats fournissent des preuves solides que les souris DMSXL manifestent une neuropathie motrice (Panaite et al., 2010, soumis). Par conséquent, les souris DMSXL représentent pour nous un bon outil pour étudier, à l'avenir, les modifications physiologiques, morphologiques et moléculaires qui sous-tendent l'insuffisance respiratoire du DM1. La connaissance du mécanisme de déficience respiratoire en DM1 aidera à mieux cibler le traitement de ces problèmes aux patients. De plus, nos résultats pourront, à l'avenir, orienter la recherche pharmaceutique et clinique vers le développement de thérapie contre le déficit respiratoire associé à DM1.
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Myotonic dystrophy (DM1) is a multisystemic disease caused by an expansion of CTG repeats in the region of DMPK, the gene encoding DM protein kinase. The severity of muscle disability in DM1 correlates with the size of CTG expansion. As respiratory failure is one of the main causes of death in DM1, we investigated the correlation between respiratory impairment and size of the (CTG)n repeat in DM1 animal models. Using pressure plethysmography the respiratory function was assessed in control and transgenic mice carrying either 600 (DM600) or >1300 CTG repeats (DMSXL). The statistical analysis of respiratory parameters revealed that both DM1 transgenic mice sub-lines show respiratory impairment compared to control mice. In addition, there is no significant difference in breathing functions between the DM600 and DMSXL mice. In conclusion, these results indicate that respiratory impairment is present in both transgenic mice sub-lines, but the severity of respiratory failure is not related to the size of the (CTG)n expansion.
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Occupational exposure modeling is widely used in the context of the E.U. regulation on the registration, evaluation, authorization, and restriction of chemicals (REACH). First tier tools, such as European Centre for Ecotoxicology and TOxicology of Chemicals (ECETOC) targeted risk assessment (TRA) or Stoffenmanager, are used to screen a wide range of substances. Those of concern are investigated further using second tier tools, e.g., Advanced REACH Tool (ART). Local sensitivity analysis (SA) methods are used here to determine dominant factors for three models commonly used within the REACH framework: ECETOC TRA v3, Stoffenmanager 4.5, and ART 1.5. Based on the results of the SA, the robustness of the models is assessed. For ECETOC, the process category (PROC) is the most important factor. A failure to identify the correct PROC has severe consequences for the exposure estimate. Stoffenmanager is the most balanced model and decision making uncertainties in one modifying factor are less severe in Stoffenmanager. ART requires a careful evaluation of the decisions in the source compartment since it constitutes ∼75% of the total exposure range, which corresponds to an exposure estimate of 20-22 orders of magnitude. Our results indicate that there is a trade off between accuracy and precision of the models. Previous studies suggested that ART may lead to more accurate results in well-documented exposure situations. However, the choice of the adequate model should ultimately be determined by the quality of the available exposure data: if the practitioner is uncertain concerning two or more decisions in the entry parameters, Stoffenmanager may be more robust than ART.
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BACKGROUND: Artemether-lumefantrine is the most widely used artemisinin-based combination therapy for malaria, although treatment failures occur in some regions. We investigated the effect of dosing strategy on efficacy in a pooled analysis from trials done in a wide range of malaria-endemic settings. METHODS: We searched PubMed for clinical trials that enrolled and treated patients with artemether-lumefantrine and were published from 1960 to December, 2012. We merged individual patient data from these trials by use of standardised methods. The primary endpoint was the PCR-adjusted risk of Plasmodium falciparum recrudescence by day 28. Secondary endpoints consisted of the PCR-adjusted risk of P falciparum recurrence by day 42, PCR-unadjusted risk of P falciparum recurrence by day 42, early parasite clearance, and gametocyte carriage. Risk factors for PCR-adjusted recrudescence were identified using Cox's regression model with frailty shared across the study sites. FINDINGS: We included 61 studies done between January, 1998, and December, 2012, and included 14 327 patients in our analyses. The PCR-adjusted therapeutic efficacy was 97·6% (95% CI 97·4-97·9) at day 28 and 96·0% (95·6-96·5) at day 42. After controlling for age and parasitaemia, patients prescribed a higher dose of artemether had a lower risk of having parasitaemia on day 1 (adjusted odds ratio [OR] 0·92, 95% CI 0·86-0·99 for every 1 mg/kg increase in daily artemether dose; p=0·024), but not on day 2 (p=0·69) or day 3 (0·087). In Asia, children weighing 10-15 kg who received a total lumefantrine dose less than 60 mg/kg had the lowest PCR-adjusted efficacy (91·7%, 95% CI 86·5-96·9). In Africa, the risk of treatment failure was greatest in malnourished children aged 1-3 years (PCR-adjusted efficacy 94·3%, 95% CI 92·3-96·3). A higher artemether dose was associated with a lower gametocyte presence within 14 days of treatment (adjusted OR 0·92, 95% CI 0·85-0·99; p=0·037 for every 1 mg/kg increase in total artemether dose). INTERPRETATION: The recommended dose of artemether-lumefantrine provides reliable efficacy in most patients with uncomplicated malaria. However, therapeutic efficacy was lowest in young children from Asia and young underweight children from Africa; a higher dose regimen should be assessed in these groups. FUNDING: Bill & Melinda Gates Foundation.
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BACKGROUND: The mechanism behind early graft failure after right ventricular outflow tract (RVOT) reconstruction is not fully understood. Our aim was to establish a three-dimensional computational fluid dynamics (CFD) model of RVOT to investigate the hemodynamic conditions that may trigger the development of intimal hyperplasia and arteriosclerosis. METHODS: Pressure, flow, and diameter at the RVOT, pulmonary artery (PA), bifurcation of the PA, and left and right PAs were measured in 10 normal pigs with a mean weight of 24.8 ± 0.78 kg. Data obtained from the experimental scenario were used for CFD simulation of pressure, flow, and shear stress profile from the RVOT to the left and right PAs. RESULTS: Using experimental data, a CFD model was obtained for 2.0 and 2.5-L/min pulsatile inflow profiles. In both velocity profiles, time and space averaged in the low-shear stress profile range from 0-6.0 Pa at the pulmonary trunk, its bifurcation, and at the openings of both PAs. These low-shear stress areas were accompanied to high-pressure regions 14.0-20.0 mm Hg (1866.2-2666 Pa). Flow analysis revealed a turbulent flow at the PA bifurcation and ostia of both PAs. CONCLUSIONS: Identified local low-shear stress, high pressure, and turbulent flow correspond to a well-defined trigger pattern for the development of intimal hyperplasia and arteriosclerosis. As such, this real-time three-dimensional CFD model may in the future serve as a tool for the planning of RVOT reconstruction, its analysis, and prediction of outcome.