52 resultados para FAILURE RATE-FUNCTION
em QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast
Resumo:
Intermedin/adrenomedullin-2 (IMD) is a member of the adrenomedullin/CGRP peptide family. Less is known about the distribution of IMD than for other family members within the mammalian cardiovascular system, particularly in humans. The aim was to evaluate plasma IMD levels in healthy subjects and patients with chronic heart failure. IMD and its precursor fragments, preproIMD25–56 and preproIMD57–92, were measured by radioimmunoassay in 75 healthy subjects and levels of IMD were also compared to those of adrenomedullin (AM) and mid-region proadrenomedullin45–92 (MRproAM45–92) in 19 patients with systolic heart failure (LVEF < 45%). In healthy subjects, plasma levels (mean + SE) of IMD (6.3 + 0.6 pg ml−1) were lower than, but correlated with those of AM (25.8 + 1.8 pg ml−1; r = 0.49, p < 0.001). Plasma preproIMD25–56 (39.6 + 3.1 pg ml−1), preproIMD57–92 (25.9 + 3.8 pg ml−1) and MRproAM45–92 (200.2 + 6.7 pg ml−1) were greater than their respective bioactive peptides. IMD levels correlated positively with BMI but not age, and were elevated in heart failure (9.8 + 1.3 pg ml−1, p < 0.05), similarly to MRproAM45–92 (329.5 + 41.9 pg ml−1, p < 0.001) and AM (56.8 + 10.9 pg ml−1, p < 0.01). IMD levels were greater in heart failure patients with concomitant renal impairment (11.3 + 1.8 pg ml−1) than those without (6.5 + 1.0 pg ml−1; p < 0.05). IMD and AM were greater in patients receiving submaximal compared with maximal heart failure drug therapy and were decreased after 6 months of cardiac resynchronization therapy. In conclusion, IMD is present in the plasma of healthy subjects less abundantly than AM, but is similarly correlated weakly with BMI. IMD levels are elevated in heart failure, especially with concomitant renal impairment, and tend to be reduced by high intensity drug or pacing therapy.
Resumo:
We propose a complete application capable of tracking multiple objects in an environment monitored by multiple cameras. The system has been specially developed to be applied to sport games, and it has been evaluated in a real association-football stadium. Each target is tracked using a local importance-sampling particle filter in each camera, but the final estimation is made by combining information from the other cameras using a modified unscented Kalman filter algorithm. Multicamera integration enables us to compensate for bad measurements or occlusions in some cameras thanks to the other views it offers. The final algorithm results in a more accurate system with a lower failure rate. (C) 2009 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3114605]
Resumo:
PURPOSE: Active surveillance is increasingly accepted as a treatment option for favorable-risk prostate cancer. Long-term follow-up has been lacking. In this study, we report the long-term outcome of a large active surveillance protocol in men with favorable-risk prostate cancer.
PATIENTS AND METHODS: In a prospective single-arm cohort study carried out at a single academic health sciences center, 993 men with favorable- or intermediate-risk prostate cancer were managed with an initial expectant approach. Intervention was offered for a prostate-specific antigen (PSA) doubling time of less than 3 years, Gleason score progression, or unequivocal clinical progression. Main outcome measures were overall and disease-specific survival, rate of treatment, and PSA failure rate in the treated patients.
RESULTS: Among the 819 survivors, the median follow-up time from the first biopsy is 6.4 years (range, 0.2 to 19.8 years). One hundred forty-nine (15%) of 993 patients died, and 844 patients are alive (censored rate, 85.0%). There were 15 deaths (1.5%) from prostate cancer. The 10- and 15-year actuarial cause-specific survival rates were 98.1% and 94.3%, respectively. An additional 13 patients (1.3%) developed metastatic disease and are alive with confirmed metastases (n = 9) or have died of other causes (n = 4). At 5, 10, and 15 years, 75.7%, 63.5%, and 55.0% of patients remained untreated and on surveillance. The cumulative hazard ratio for nonprostate-to-prostate cancer mortality was 9.2:1.
CONCLUSION: Active surveillance for favorable-risk prostate cancer is feasible and seems safe in the 15-year time frame. In our cohort, 2.8% of patients have developed metastatic disease, and 1.5% have died of prostate cancer. This mortality rate is consistent with expected mortality in favorable-risk patients managed with initial definitive intervention.
Resumo:
This chapter seeks to explain the relative stability of the British banking system in terms of its capital structure. From 1826 joint-stock banking was allowed, but shareholder liability was jointly and severally unlimited. Limited liability banks were allowed from 1857–8, but these banks issued partly paid shares with an obligation on shareholders to subscribe for uncalled capital. Contingent capital meant that shareholders and managers would suffer losses in the event of failure and this discouraged risk shifting at the expense of note-holders and depositors. Although individual banks collapsed, the failure rate of banks (in terms of number or capital) did not reach a critical level—10 per cent—beyond which the payments system might have been threatened. This chapter argues that agency problems and systemic risk rose after the abolition of contingent share capital in 1958 and the deregulation of the banking sector in the 1970s.
Resumo:
INTRODUCTION: EGFR screening requires good quality tissue, sensitivity and turn-around time (TAT). We report our experience of routine screening, describing sample type, TAT, specimen quality (cellularity and DNA yield), histopathological description, mutation result and clinical outcome. METHODS: Non-small cell lung cancer (NSCLC) sections were screened for EGFR mutations (M+) in exons 18-21. Clinical, pathological and screening outcome data were collected for year 1 of testing. Screening outcome alone was collected for year 2. RESULTS: In year 1, 152 samples were tested, most (72%) were diagnostic. TAT was 4.9 days (95%confidence interval (CI)=4.5-5.5). EGFR-M+ prevalence was 11% and higher (20%) among never-smoking women with adenocarcinomas (ADCs), but 30% of mutations occurred in current/ex-smoking men. EGFR-M+ tumours were non-mucinous ADCs and 100% thyroid transcription factor (TTF1+). No mutations were detected in poorly differentiated NSCLC-not otherwise specified (NOS). There was a trend for improved overall survival (OS) among EGFR-M+ versus EGFR-M- patients (median OS=78 versus 17 months). In year 1, test failure rate was 19%, and associated with scant cellularity and low DNA concentrations. However 75% of samples with poor cellularity but representative of tumour were informative and mutation prevalence was 9%. In year 2, 755 samples were tested; mutation prevalence was 13% and test failure only 5.4%. Although samples with low DNA concentration (2.2 ng/μL), the mutation rate was 9.2%. CONCLUSION: Routine epidermal growth factor receptor (EGFR) screening using diagnostic samples is fast and feasible even on samples with poor cellularity and DNA content. Mutations tend to occur in better-differentiated non-mucinous TTF1+ ADCs. Whether these histological criteria may be useful to select patients for EGFR testing merits further investigation.
Resumo:
PURPOSE: To investigate whether failure to suppress the prostate-specific antigen (PSA) level to /=2 months of neoadjuvant luteinizing hormone-releasing hormone agonist therapy in patients scheduled to undergo external beam radiotherapy for localized prostate carcinoma is associated with reduced biochemical failure-free survival. METHODS AND MATERIALS: A retrospective case note review of consecutive patients with intermediate- or high-risk localized prostate cancer treated between January 2001 and December 2002 with neoadjuvant hormonal deprivation therapy, followed by concurrent hormonal therapy and radiotherapy was performed. Patient data were divided for analysis according to whether the PSA level in Week 1 of radiotherapy was 1 ng/mL in 52. At a median follow-up of 49 months, the 4-year actuarial biochemical failure-free survival rate was 84% vs. 60% (p = 0.0016) in favor of the patients with a PSA level after neoadjuvant hormonal deprivation therapy of 1 ng/mL at the beginning of external beam radiotherapy after >/=2 months of neoadjuvant luteinizing hormone-releasing hormone agonist therapy have a significantly greater rate of biochemical failure and lower survival rate compared with those with a PSA level of
Resumo:
BACKGROUND: The failure of a kidney transplant is now a common reason for initiation of dialysis therapy. Kidney transplant recipients commencing dialysis have greater morbidity and mortality than transplant-naïve, incident dialysis patients. This study aimed to identify variables associated with survival after graft failure.
METHODS: All recipients of first, deceased donor kidney transplants performed in Northern Ireland between 1986 and 2005 who had a functioning graft at 12 months were included (n = 585). Clinical and blood-derived variables (age, gender, primary renal disease, diabetic status, smoking status, human leukocyte antigen (HLA) mismatch, acute rejection episodes, immunosuppression, cardiovascular disease, graft survival, haemoglobin, albumin, phosphate, C reactive protein, estimated glomerular filtration rate (eGFR), rate of eGFR decline, dialysis modality, and access) were collected prospectively and investigated for association with re-transplantation and survival. The association between re-transplantation and survival was explored by modelling re-transplantation as a time-dependent covariate.
RESULTS: Median follow-up time was 12.1 years. Recipients with a failing graft (158/585) demonstrated rapid loss of eGFR prior to graft failure, reducing the time available to plan for alternative renal replacement therapy. Median survival after graft failure was 3.0 years. In multivariate analysis, age and re-transplantation were associated with survival after graft failure. Re-transplantation was associated with an 88% reduction in mortality.
CONCLUSIONS: Optimal management of kidney transplant recipients with failing grafts requires early recognition of declining function and proactive preparation for re-transplantation given the substantial survival benefit this confers. The survival benefit associated with re-transplantation persists after prolonged exposure to immunosuppressive therapy.
Resumo:
We propose a new selective multi-carrier index keying in orthogonal frequency division multiplexing (OFDM) systems that opportunistically modulate both a small subset of sub-carriers and their indices. Particularly, we investigate the performance enhancement in two cases of error propagation sensitive and compromised deviceto-device (D2D) communications. For the performance evaluation, we focus on analyzing the error propagation probability (EPP) introducing the exact and upper bound expressions on the detection error probability, in the presence of both imperfect and perfect detection of active multi-carrier indices. The average EPP results in closedform are generalized for various fading distribution using the moment generating function, and our numerical results clearly show that the proposed approach is desirable for reliable and energy-efficient D2D applications.
Resumo:
Aims: To assess the reliability of drug use reports by young respondents, this study examined the extent of recanting previous drug use reports within an ongoing longitudinal survey of adolescent drug use. Here, recanting was defined as a positive report of life-time drug use that was subsequently denied 1 year later. The covariates of recanting were also studied. Design: An ongoing longitudinal survey of young adolescents (Belfast Youth Development Study) in Northern Ireland. Setting: Pencil and paper questionnaires were administered to pupils within participating schools. Measurements: Measures analysed included (a) recanting rates across 13 substances, (b) educational characteristics, (c) offending behaviour and (d) socioeconomic status. Findings: High levels of drug use recanting were identified, ranging from 7% of past alcohol use to 87% of past magic mushroom use. Recanting increased with the social stigma of the substance used. Denying past alcohol use was associated with being male, attending a catholic school, having positive attitudes towards school, having negative education expectations and not reporting any offending behaviour. Recanting alcohol intoxication was associated with being male and not reporting serious offending behaviour. Cannabis recanting was associated with having negative education expectations, receiving drugs education and not reporting serious offending behaviour. Conclusions: The high levels of recanting uncovered cast doubts on the reliability of drug use reports from young adolescents. Failure to address this response error may lead to biased prevalence estimates, particularly within school surveys and drug education evaluation trials.
Resumo:
Langerin is a C-type lectin expressed by a subset of dendritic leukocytes, the Langerhans cells (LC). Langerin is a cell surface receptor that induces the formation of an LC-specific organelle, the Birbeck granule (BG). We generated a langerin(-/-) mouse on a C57BL/6 background which did not display any macroscopic aberrant development. In the absence of langerin, LC were detected in normal numbers in the epidermis but the cells lacked BG. LC of langerin(-/-) mice did not present other phenotypic alterations compared to wild-type littermates. Functionally, the langerin(-/-) LC were able to capture antigen, to migrate towards skin draining lymph nodes, and to undergo phenotypic maturation. In addition, langerin(-/-) mice were not impaired in their capacity to process native OVA protein for I-A(b)-restricted presentation to CD4(+) T lymphocytes or for H-2K(b)-restricted cross-presentation to CD8(+) T lymphocytes. langerin(-/-) mice inoculated with mannosylated or skin-tropic microorganisms did not display an altered pathogen susceptibility. Finally, chemical mutagenesis resulted in a similar rate of skin tumor development in langerin(-/-) and wild-type mice. Overall, our data indicate that langerin and BG are dispensable for a number of LC functions. The langerin(-/-) C57BL/6 mouse should be a valuable model for further functional exploration of langerin and the role of BG.
Resumo:
Wireless enabled portable devices must operate with the highest possible energy efficiency while still maintaining a minimum level and quality of service to meet the user's expectations. The authors analyse the performance of a new pointer-based medium access control protocol that was designed to significantly improve the energy efficiency of user terminals in wireless local area networks. The new protocol, pointer controlled slot allocation and resynchronisation protocol (PCSAR), is based on the existing IEEE 802.11 point coordination function (PCF) standard. PCSAR reduces energy consumption by removing the need for power saving stations to remain awake and listen to the channel. Using OPNET, simulations were performed under symmetric channel loading conditions to compare the performance of PCSAR with the infrastructure power saving mode of IEEE 802.11, PCF-PS. The simulation results demonstrate a significant improvement in energy efficiency without significant reduction in performance when using PCSAR. For a wireless network consisting of an access point and 8 stations in power saving mode, the energy saving was up to 31% while using PCSAR instead of PCF-PS, depending upon frame error rate and load. The results also show that PCSAR offers significantly reduced uplink access delay over PCF-PS while modestly improving uplink throughput.
Resumo:
The greatest relaxation time for an assembly of three- dimensional rigid rotators in an axially symmetric bistable potential is obtained exactly in terms of continued fractions as a sum of the zero frequency decay functions (averages of the Legendre polynomials) of the system. This is accomplished by studying the entire time evolution of the Green function (transition probability) by expanding the time dependent distribution as a Fourier series and proceeding to the zero frequency limit of the Laplace transform of that distribution. The procedure is entirely analogous to the calculation of the characteristic time of the probability evolution (the integral of the configuration space probability density function with respect to the position co-ordinate) for a particle undergoing translational diffusion in a potential; a concept originally used by Malakhov and Pankratov (Physica A 229 (1996) 109). This procedure allowed them to obtain exact solutions of the Kramers one-dimensional translational escape rate problem for piecewise parabolic potentials. The solution was accomplished by posing the problem in terms of the appropriate Sturm-Liouville equation which could be solved in terms of the parabolic cylinder functions. The method (as applied to rotational problems and posed in terms of recurrence relations for the decay functions, i.e., the Brinkman approach c.f. Blomberg, Physica A 86 (1977) 49, as opposed to the Sturm-Liouville one) demonstrates clearly that the greatest relaxation time unlike the integral relaxation time which is governed by a single decay function (albeit coupled to all the others in non-linear fashion via the underlying recurrence relation) is governed by a sum of decay functions. The method is easily generalized to multidimensional state spaces by matrix continued fraction methods allowing one to treat non-axially symmetric potentials, where the distribution function is governed by two state variables. (C) 2001 Elsevier Science B.V. All rights reserved.
Resumo:
Objectives: It is increasingly important to develop predictors of treatment response and outcome in schizophrenia. Neuropsychological impairments, particularly those reflecting frontal lobe function, appear to predict poor outcome. Eye movement abnormalities probably also reflect frontal lobe deficits. We wished to see if these two aspects of schizophrenia were correlated and whether they could distinguish a treatment resistant from a treatment responsive group. Methods: Ten treatment resistant schizophrenic patients were compared with ten treatment responsive patients on three eye movement paradigms (reflexive saccades, antisaccades and smooth pursuit), clinical psychopathology (BPRS, SANS and CGI) and a neuropsychological test battery designed to detect frontal lobe dysfunction. Ten aged-matched controls also carried out the eye movement tasks. Results: Both treatment responsive (p = 0.038) and treatment resistant (p = 0.007) patients differed significantly from controls on the antisaccade task. The treatment resistant group had a higher error rate than the treatment responsive group, but the difference was not statistically significant. Similar poor neuropsychological test performance was found in both groups. Conclusions: To demonstrate the biological differences characteristic of treatment resistance, larger sample sizes and wider differences in outcome between the two groups are necessary.
Resumo:
Fasciola hepatica secretes cathepsin L proteases that facilitate the penetration of the parasite through the tissues of its host, and also participate in functions such as feeding and immune evasion. The major proteases, cathepsin L1 (FheCL1) and cathepsin L2 (FheCL2) are members of a lineage that gave rise to the human cathepsin Ls, Ks and Ss, but while they exhibit similarities in their substrate specificities to these enzymes they differ in having a wider pH range for activity and an enhanced stability at neutral pH. There are presently 13 Fasciola cathepsin L cDNAs deposited in the public databases representing a gene family of at least seven distinct members, although the temporal and spatial expression of each of these members in the developmental stage of F. hepatica remains unclear. Immunolocalisation and in situ hybridisation studies, using antibody and DNA probes, respectively, show that the vast majority of cathepsin L gene expression is carried out in the epithelial cells lining the parasite gut. Within these cells the enzyme is packaged into secretory vesicles that release their contents into the gut lumen for the purpose of degrading ingested host tissue and blood. Liver flukes also express a novel multi-domain cystatin that may be involved in the regulation of cathepsin L activity. Vaccine trials in both sheep and cattle with purified native FheCL1 and FheCL2 have shown that these enzymes can induce protection, ranging from 33 to 79%, to experimental challenge with metacercariae of F. hepatica, and very potent anti-embryonation/hatch rate effects that would block parasite transmission. In this article we review the vaccine trials carried out over the past 8 years, the role of antibody and T cell responses in mediating protection and discuss the prospects of the cathepsin Ls in the development of first generation recombinant liver fluke vaccines. Author Keywords: Helminths; Trematodes; Parasites; Cathepsins; Proteases; Vaccines; Immunology; Biochemistry