Identifiability and estimation of the sign of a covariate effect in the competing risks model.

It is well known that the competing risks model is identified if the dependence structure between risks (the copula function) is known or assumed. Special cases include independence of risks or independent censoring. If the copula function is not specified, parameters of interest are only set identified. As these sets are often wide in applications, it is difficult to obtain informative results. In this paper we strike a balance between imposing too much and too little structure. By establishing a general link between observable changes in subdistributions (cumulative incidence curves) and the sign of changes in marginal distributions (the causal treatment effect) we are able to show the identifiability of the latter if the copula function is independent of the varying covariate. This has two important implications: First, it is possible to obtain informative results even if the copula function is mainly unspecified or unknown. Second, the sign of the covariate effect tends to be invariant with respect to the chosen dependence structure. Our method is computationally very simple and our simulations suggest that it identifies and consistently estimates the sign of the treatment effect for large sets of duration times. An application to unemployment duration data illustrates the usefulness of our method for empirical research.dependent censoring, nonparametric estimation, bootstrap

A Regression Model for the Copula Graphic Estimator

We consider a dependent competing risks model with many risks and many covariates. We show identifiability of the marginal distributions of latent variables for a given dependence structure. Instead of directly estimating these distributions, we suggest a plug-in regression framework for the Copula-Graphic estimator which utilises a consistent estimator for the cumulative incidence curves. Our model is an attractive empirical approach as it does not require knowledge of the marginal distributions which are typically unknown in applications. We illustrate the applicability of our approach with the help of a parametric unemployment duration model with an unknown dependence structure. We construct identification bounds for the marginal distributions and partial effects in response to covariate changes. The bounds for the partial effects are surprisingly tight and often reveal the direction of the covariate effect.Archimedean copula, dependent censoring

Bounds analysis of competing risks: a nonparametric evaluation of the effect of unemployment benefits on migration in Germany

"In this paper we derive nonparametric bounds for the cumulative incidence curve within a competing risks model with partly identified interval data. As an advantage over earlier attempts our approach also gives valid results in case of dependent competing risks. We apply our framework to empirically evaluate the effect of unemployment benefits on observed migration of unemployed workers in Germany. Our findings weakly indicate that reducing the entitlement length for unemployment benefits increases migration among high-skilled individuals."(author's abstract

International consensus recommendations on the diagnostic work-up for malformations of cortical development

Malformations of cortical development (MCDs) are neurodevelopmental disorders that result from abnormal development of the cerebral cortex in utero. MCDs place a substantial burden on affected individuals, their families and societies worldwide, as these individuals can experience lifelong drug-resistant epilepsy, cerebral palsy, feeding difficulties, intellectual disability and other neurological and behavioural anomalies. The diagnostic pathway for MCDs is complex owing to wide variations in presentation and aetiology, thereby hampering timely and adequate management. In this article, the international MCD network Neuro-MIG provides consensus recommendations to aid both expert and non-expert clinicians in the diagnostic work-up of MCDs with the aim of improving patient management worldwide. We reviewed the literature on clinical presentation, aetiology and diagnostic approaches for the main MCD subtypes and collected data on current practices and recommendations from clinicians and diagnostic laboratories within Neuro-MIG. We reached consensus by 42 professionals from 20 countries, using expert discussions and a Delphi consensus process. We present a diagnostic workflow that can be applied to any individual with MCD and a comprehensive list of MCD-related genes with their associated phenotypes. The workflow is designed to maximize the diagnostic yield and increase the number of patients receiving personalized care and counselling on prognosis and recurrence risk

The potential diagnostic yield of whole exome sequencing in pregnancies complicated by fetal ultrasound anomalies

Introduction: The aim of this retrospective cohort study was to determine the potential diagnostic yield of prenatal whole exome sequencing in fetuses with structural anomalies on expert ultrasound scans and normal chromosomal microarray results. Material and methods: In the period 2013-2016, 391 pregnant women with fetal ultrasound anomalies who received normal chromosomal microarray results, were referred for additional genetic counseling and opted for additional molecular testing pre- and/or postnatally. Most of the couples received only a targeted molecular test and in 159 cases (40.7%) whole exome sequencing (broad gene panels or open exome) was performed. The results of these molecular tests were evaluated retrospectively, regardless of the time of the genetic diagnosis (prenatal or postnatal). Results: In 76 of 391 fetuses (19.4%, 95% CI 15.8%-23.6%) molecular testing provided a genetic diagnosis with identification of (likely) pathogenic variants. In the majority of cases (91.1%, 73/76) the (likely) pathogenic variant would be detected by prenatal whole exome sequencing analysis. Conclusions: Our retrospective cohort study shows that prenatal whole exome sequencing, if offered by a clinical geneticist, in addition to chromosomal microarray, would notably incre

Plasma glial fibrillary acidic protein is raised in progranulin-associated frontotemporal dementia

Background There are few validated fluid biomarkers in frontotemporal dementia (FTD). Glial fibrillary acidic protein (GFAP) is a measure of astrogliosis, a known pathological process of FTD, but has yet to be explored as potential biomarker. Methods Plasma GFAP and neurofilament light chain (NfL) concentration were measured in 469 individuals enrolled in the Genetic FTD Initiative: 114 C9orf72 expansion carriers (74 presymptomatic, 40 symptomatic), 119 GRN mutation carriers (88 presymptomatic, 31 symptomatic), 53 MAPT mutation carriers (34 presymptomatic, 19 symptomatic) and 183 non-carrier controls. Biomarker measures were compared between groups using linear regression models adjusted for age and sex with family membership included as random effect. Participants underwent standardised clinical assessments including the Mini-Mental State Examination (MMSE), Frontotemporal Lobar Degeneration-C linical Dementia Rating scale and MRI. Spearman's correlation coefficient was used to investigate the relationship of plasma GFAP to clinical and imaging measures. Results Plasma GFAP concentration was significantly increased in symptomatic GRN mutation carriers (adjusted mean difference from controls 192.3 pg/mL, 95% CI 126.5 to 445.6), but not in those with C9orf72 expansions (9.0, -61.3 to 54.6), MAPT mutations (12.7, -33.3 to 90.4) or the presymptomatic groups. GFAP concentration was significantly positively correlated with age in both controls and the majority of the disease groups, as well as with NfL concentration. In the presymptomatic period, higher GFAP concentrations were correlated with a lower cognitive score (MMSE) and lower brain volume, while in the symptomatic period, higher concentrations were associated with faster rates of atrophy in the temporal lobe. Conclusions Raised GFAP concentrations appear to be unique to GRN-related FTD, with levels potentially increasing just prior to symptom onset, suggesting that GFAP may be an important marker of proximity to onset, and helpful for forthcoming therapeutic prevention trials

Biochemical processes for geothermal brine treatment

As part of the DOE Geothermal Energy Program, BNL`s Advanced Biochemical Processes for Geothermal Brines (ABPGB) project is aimed at the development of cost-efficient and environmentally acceptable technologies for the disposal of geothermal wastes. Extensive chemical studies of high and low salinity brines and precipitates have indicated that in addition to trace quantities of regulated substances, e.g., toxic metals such as arsenic and mercury, there are significant concentrations of valuable metals, including gold, silver and platinum. Further chemical and physical studies of the silica product have also shown that the produced silica is a valuable material with commercial potential. A combined biochemical and chemical technology is being developed which (1) solubilizes, separates, and removes environmentally regulated constituents in geothermal precipitates and brines, (2) generates an amorphous silica product which may be used as feedstock for the production of revenue generating materials, (3) recover economically valuable trace metals and salts. Geothermal power resources which utilize low salinity brines and use the Stretford process for hydrogen sulfide abatement generate a contaminated sulfur cake. Combined technology converts such sulfur to a commercial grade sulfur, suitable for agricultural use. The R and D activities at BNL are conducted jointly with industrial parties in an effort focused on field applications

Reduced incidence of infusion-related reactions in metastatic colorectal cancer during treatment with cetuximab plus irinotecan with combined corticosteroid and antihistamine premedication

BACKGROUND: The multinational MABEL study of 1147 patients with metastatic colorectal cancer (mCRC) who had recently failed an irinotecan-containing regimen confirmed in a community practice setting the efficacy and safety of cetuximab combined with irinotecan. METHODS: This report describes a post hoc analysis of the influence of prophylactic premedication on the incidence of infusion-related reactions (IRRs) in the MABEL study. The analysis was focused on the subpopulation of patients premedicated with antihistamines either with (n = 700) or without (n = 422) corticosteroids. Stepwise Cox regression modeling was used to examine the explanatory value of the type of premedication on progression-free survival (PFS) and overall survival (OS) times. RESULTS: The incidence of IRRs was lower in the group of patients who received antihistamine plus corticosteroid (9.6%) compared with those who received antihistamine alone (25.6%). A similar trend was seen for grade 3 or 4 IRRs (1.0% vs 4.7%, respectively). The 12-week PFS rates (61% vs 60%), median PFS (16.1 vs 13.1 weeks) and OS (9.2 vs 9.0 months) times for patients who received, respectively, antihistamines with and without corticosteroids were similar. Cox regression modeling did not identify any impact of type of premedication used (antihistamine with or without corticosteroids) on the efficacy of treatment in relation to PFS or OS. CONCLUSIONS: Prophylactically premedicating mCRC patients with both antihistamine and a corticosteroid appeared to reduce the frequency of cetuximab-associated IRRs. Given that this was a post hoc analysis, caution must be exercised in the interpretation of these data, which require formal confirmation in a randomized study

Cetuximab plus irinotecan in heavily pretreated metastatic colorectal cancer progressing on irinotecan : MABEL study

Purpose: This large, multinational study aimed to confirm in a community practice setting the efficacy and safety of cetuximab plus irinotecan in patients with epidermal growth factor-expressing metastatic colorectal cancer (mCRC) who had recently failed an irinotecan-containing regimen. Patients and Methods: The primary objective was to determine the progression-free survival (PFS) rate at 12 weeks. The initial cetuximab dose was 400 mg/m2 and was followed weekly by 250 mg/m2; irinotecan (according to prestudy regimen) was given weekly (125 mg/m2 weekly for 4 of 6 weeks), every 2 weeks (180 mg/m2 each), or every 3 weeks (350 mg/m2 each). Results: The intention-to-treat/safety population comprised 1,147 treated patients who received irinotecan weekly (n = 93); every 2 weeks (n = 670); every 3 weeks (n = 356); or another dose (n = 28). The PFS rate at 12 weeks was 61%, and the median survival was 9.2 months. Treatment was generally well tolerated. The most common treatment-related grades 3 to 4 adverse events were diarrhea (19%), neutropenia (10%), rash (7%), and asthenia (6%). The rate of grades 3 to 4 infusion-related reactions (IRRs; composite adverse event category) was 1% for patients who received both antihistamine and corticosteroid premedication. Conclusion: Tolerability (except IRR incidence), PFS rate, and overall survival rate were in line with previous results. At 1%, the rate of IRRs in patients who received prophylactic premedication with both antihistamine and corticosteroid is lower than previously reported. MABEL clearly confirms in a community practice setting the efficacy and safety of cetuximab plus irinotecan in the treatment of mCRC