127 research outputs found

    Automating Model Comparison in Factor Graphs

    Full text link
    Bayesian state and parameter estimation have been automated effectively in the literature, however, this has not yet been the case for model comparison, which therefore still requires error-prone and time-consuming manual derivations. As a result, model comparison is often overlooked and ignored, despite its importance. This paper efficiently automates Bayesian model averaging, selection, and combination by message passing on a Forney-style factor graph with a custom mixture node. Parameter and state inference, and model comparison can then be executed simultaneously using message passing with scale factors. This approach shortens the model design cycle and allows for the straightforward extension to hierarchical and temporal model priors to accommodate for modeling complicated time-varying processes

    Diagnostic accuracy of positron emission tomography tracers for the differentiation of tumor progression from treatment-related changes in high-grade glioma:a systematic review and meta-analysis

    Get PDF
    Background: Post-treatment high-grade gliomas are usually monitored with contrast-enhanced MRI, but its diagnostic accuracy is limited as it cannot adequately distinguish between true tumor progression and treatment-related changes. According to recent response assessment in neuro-oncology (RANO) recommendations PET overcomes this limitation. However, it is currently unknown which tracer yields the best results. Therefore, a systematic review and meta-analysis were performed to compare the diagnostic accuracy of the different PET tracers in differentiating tumor progression from treatment-related changes in high-grade glioma patients. Methods: Pubmed, Web of Science and Embase were searched systematically. Study selection, data extraction and quality assessment were performed independently by two authors. Meta-analysis was performed using a bivariate random effects model when ≥ 5 studies were included. Results: 39 studies (11 tracers) were included in the systematic review. 18F-FDG (12 studies, 171 lesions) showed a pooled sensitivity and specificity of 84% (95%CI 72-92) and 84% (69-93), respectively. 18F-FET (7 studies, 172 lesions) demonstrated a sensitivity of 90% (81-95) and specificity of 85% (71-93). 11C-MET (8 studies, 151 lesions) sensitivity was 93% (80-98) and specificity was 82% (68-91). The number of included studies for the other tracers were too low to combine, but sensitivity and specificity ranged between 93-100% and 0-100% for 18F-FLT, 85-100% and 72-100% for 18F-FDOPA and 100% and 70-88% for 11C-CHO, respectively. Conclusion:18F-FET and 11C-MET, both amino-acid tracers, showed a comparable higher sensitivity than 18F-FDG in the differentiation between tumor progression and treatment-related changes in high-grade glioma patients. The evidence for other tracers is limited, thus 18F-FET and 11C-MET are preferred when available. Our results support the incorporation of amino-acid PET tracers for the treatment evaluation of high-grade gliomas

    European reference network for rare vascular diseases (VASCERN) consensus statement for the screening and management of patients with pathogenic ACTA2 variants

    Get PDF
    Malaltia aòrtica; Dissecció; Aneurisma aòrtic toràcicEnfermedad aórtica; Disección; Aneurisma de aorta torácicaAortic disease; Dissection; Thoracic aortic aneurysmThe ACTA2 gene encodes for smooth muscle specific α-actin, a critical component of the contractile apparatus of the vascular smooth muscle cell. Pathogenic variants in the ACTA2 gene are the most frequently encountered genetic cause of non-syndromic hereditary thoracic aortic disease (HTAD). Although thoracic aortic aneurysm and/or dissection is the main clinical manifestation, a variety of occlusive vascular disease and extravascular manifestations occur in ACTA2-related vasculopathy. Current data suggest possible mutation-specific manifestations of vascular and extra-aortic traits. Despite its relatively high prevalence, comprehensive recommendations on the care of patients and families with pathogenic variants in ACTA2 have not yet been established. We aimed to develop a consensus document to provide medical guidance for health care professionals involved in the diagnosis and treatment of patients and relatives with pathogenic variants in ACTA2. The HTAD Working Group of the European Reference Network for Rare Vascular Diseases (VASCERN) convened to review current literature and discuss expert opinions on clinical management of ACTA2 related vasculopathy. This consensus statement summarizes our recommendations on diagnosis, monitoring, treatment, pregnancy, genetic counselling and testing in patients with ACTA2-related vasculopathy. However, there is a clear need for additional prospective multicenter studies to further define proper guidelines.This work was supported by the Dutch Heart Foundation (2014 T007) and by an Erasmus University Rotterdam Fellowship (I.M.B.H. van de Laar)

    Female Sex and IL28B, a Synergism for Spontaneous Viral Clearance in Hepatitis C Virus (HCV) Seroconverters from a Community-Based Cohort

    Get PDF
    BACKGROUND & AIMS: Since acute hepatitis C virus (HCV) infection is often asymptomatic, it is difficult to examine the rate and determinants of spontaneous clearance. Consequently, these studies are subject to bias, which can potentially lead to biased rates of viral clearance and risk estimates. We evaluated determinants of spontaneous HCV clearance among HCV seroconverters identified in a unique community-based cohort. METHODS: Subjects were 106 drug users with documented dates of HCV seroconversion from the Amsterdam Cohort Study. Logistic regression was used to examine sociodemographic, behavioral, clinical, viral and host determinants, measured around acute infection, of HCV clearance. RESULTS: The spontaneous viral clearance rate was 33.0% (95% confidence interval (CI) 24.2-42.8). In univariate analyses female sex and fever were significantly associated with spontaneous clearance. The favorable genotypes for rs12979860 (CC) and rs8099917 (TT) were associated with spontaneous clearance, although borderline significant. In multivariate analysis, females with the favorable genotype for rs12979860 (CC) had an increased odds to spontaneously clear HCV infection (adjusted OR 6.62, 95% 2.69-26.13), whereas females with the unfavorable genotype were as likely as men with the favorable and unfavorable genotype to clear HCV. Chronic Hepatitis B infection and absence of HIV coinfection around HCV seroconversion also favor HCV clearance. CONCLUSIONS: This study shows that co-infection with HIV and HBV and genetic variation in the IL28B region play an important role in spontaneous clearance of HCV. Our findings suggest a possible synergistic interaction between female sex and IL28B in spontaneous clearance of HCV

    MEAN-pinolla tehdyn järjestelmän yksikkötestaaminen

    Get PDF
    Tämä opinnäytetyö on laadittu tilaajayritys Mekiwi Oy:n tarpeisiin ja siinä tutkitaan yksikkötestejä sekä niiden merkitystä ja hyötyjä MEAN-pinolla tehdyssä järjestelmässä. Tarve opinnäytetyölle ilmeni, kun sen kohteena olevan järjestelmän testausta haluttiin helpottaa ja automatisoida. Tavoitteena oli tuottaa yritykselle tietoa yksikkötestauksesta ja yksikkötestien rakentamisesta sekä suunnitella ja toteuttaa yksikkötestit kattamaan järjestelmän koko lähdekoodi. Alusta asti oli selvää, että tutkimusta tarvittaisiin varsin vähän, sillä työn painopiste on toiminnallisuudessa. Lähteiden sisältö onkin suurimmaksi osaksi teoriapohjaa, jolla avataan tarvittavat käsitteet ja teknologiat itse toteutusosaa varten. Käytetyistä lähteistä suurin osa on kunkin käsiteltävän asian kotisivuja. Opinnäytetyön tuloksena on kaksi sarjaa yksikkötestejä, jotka testaavat järjestelmän asiakassovelluksen käyttäjiä koskevia tietokantatoimintoja ja HTTP-rajapintoja. Lisäksi sen tuloksena saatiin tietoa tarvittavista toimenpiteistä yksikkötestien tekemisestä kattamaan koko järjestelmän koodi. Pelkkä testien kirjoittaminen ei tule riittämään, sillä sekä järjestelmän palvelin- että asiakassovelluksessa on koodia, jonka yksikkötestaaminen ilman koodimuutoksia on vähintäänkin epäluotettavaa ellei jopa mahdotonta.This thesis was made for a company called Mekiwi Oy. The subject is to examine the purpose and benefits of unit tests in a software built with the MEAN stack. The need for this thesis arose when the company wanted to improve the testing of a software and to make it more automatic. The goal was to provide information to the company about unit testing and to design and produce unit tests to cover the whole of the software’s codebase. It was clear right from the start that the need for research would be limited because the main focus would be on the functional side. The majority of the source material used is information about the concepts and technologies described either in the theory section or in the implementation section. The vast majority of the references are links to a homepage of the subject in question. The end result was two sets of unit tests: one testing the database functionalities regarding users and one testing the HTTP application programming interfaces regarding users. Information on creating unit tests to cover the entire codebase was also uncovered. Mere writing the unit testing will not be sufficient because both the client and the server have code that will need refactoring to make unit testing it possible

    Cost-Effectiveness and Cost-Utility of Early Levodopa in Parkinson's Disease

    Get PDF
    Background: In the Levodopa in EArly Parkinson's disease (LEAP) study, 445 patients were randomized to levodopa/carbidopa 100/25 mg three times per day for 80 weeks (early-start) or placebo for 40 weeks followed by levodopa/carbidopa 100/25 mg three times per day for 40 weeks (delayed-start).Objective: This paper reports the results of the economic evaluation performed alongside the LEAP-study.Methods: Early-start treatment was evaluated versus delayed-start treatment, in which the cost-effectiveness analysis (CEA) and the cost-utility analysis (CUA) were performed from the societal perspective, including health care costs among providers, non-reimbursable out-of-pocket expenses of patients, employer costs of sick leave, and lowered productivity while at work. The outcome measure for the CEA was the extra cost per unit decrease on the Unified Parkinson's Disease Rating Scale 80 weeks after baseline. The outcome measure for the CUA was the extra costs per additional quality adjusted life year (QALY) during follow-up.Results: 212 patients in the early-start and 219 patients in the delayed-start group reported use of health care resources. With savings of D 59 per patient (BCa 95% CI: -829, 788) in the early-start compared to the delayed-start group, societal costs were balanced. The early-start group showed a mean of 1.30 QALYs (BCa 95% CI: 1.26, 1.33) versus 1.30 QALYs (BCa 95% CI: 1.27, 1.33) for the delayed-start group. Because of this negligible difference, incremental cost-effectiveness and cost-utility ratios were not calculated.Conclusion: From an economic point of view, this study suggests that early treatment with levodopa is not more expensive than delayed treatment with levodopa.Neurological Motor Disorder

    Direct-Acting Antiviral Treatment for Hepatitis C Genotypes Uncommon in High-Income Countries:A Dutch Nationwide Cohort Study

    Get PDF
    Background. The majority of hepatitis C virus (HCV) infections are found in low- and middle-income countries, which harbor many region-specific HCV subtypes. Nevertheless, direct-acting antiviral (DAA) trials have almost exclusively been conducted in high-income countries, where mainly epidemically spread HCV subtypes are present. Recently, several studies have demonstrated suboptimal DAA efficacy for certain nonepidemic subtypes, which could hamper global HCV elimination. Therefore, we aimed to evaluate DAA efficacy in patients treated for a nonepidemic HCV genotype infection in the Netherlands. Methods. We performed a nationwide retrospective study including patients treated with interferon-free DAAs for an HCV genotype other than 1a/1b/2a/2b/3a/4a/4d. The genotype was determined by NS5B region phylogenetic analysis. The primary end point was SVR-12. If stored samples were available, NS5A and NS5B sequences were obtained for resistance-associated substitutions (RAS) evaluation. Results. We included 160 patients, mainly infected with nonepidemic genotype 2 (41%) and 4 (31%) subtypes. Most patients were from Africa (45%) or South America (24%); 51 (32%) were cirrhotic. SVR-12 was achieved in 92% (140/152) of patients with available SVR-12 data. Only 73% (8/11) genotype 3-infected patients achieved SVR-12, the majority being genotype 3b patients with 63% (5/8) SVR. Regardless of SVR, all genotype 3b patients had 30K and 31M RAS. Conclusions. (T)he DAA efficacy we observed in most nonepidemic genotypes in the Netherlands seems reassuring. However, the low SVR-12 rate in subtype 3b infections is alarming, especially as it is common in several HCV-endemic countries. Alongside earlier results, our results indicate that a remaining challenge for global HCV elimination is confirming and monitoring DAA efficacy in nonepidemic genotypes
    • …
    corecore