Simulation studies are computer experiments that involve creating data by pseudo‐random sampling. A key strength of simulation studies is the ability to understand the behavior of statistical methods ...because some “truth” (usually some parameter/s of interest) is known from the process of generating the data. This allows us to consider properties of methods, such as bias. While widely used, simulation studies are often poorly designed, analyzed, and reported. This tutorial outlines the rationale for using simulation studies and offers guidance for design, execution, analysis, reporting, and presentation. In particular, this tutorial provides a structured approach for planning and reporting simulation studies, which involves defining aims, data‐generating mechanisms, estimands, methods, and performance measures (“ADEMP”); coherent terminology for simulation studies; guidance on coding simulation studies; a critical discussion of key performance measures and their estimation; guidance on structuring tabular and graphical presentation of results; and new graphical presentations. With a view to describing recent practice, we review 100 articles taken from Volume 34 of Statistics in Medicine, which included at least one simulation study and identify areas for improvement.
Colorectal cancers are classified as right/left-sided based on whether they occur before/after the splenic flexure, with established differences in molecular subtypes and outcomes. However, it is ...unclear if this division is optimal and whether precise tumor location provides further information.
In 1,876 patients with colorectal cancer, we compared mutation prevalence and overall survival (OS) according to side and location. Consensus molecular subtype (CMS) was compared in a separate cohort of 608 patients.
Mutation prevalence differed by side and location for
, and
Within left- and right-sided tumors, there remained substantial variations in mutation rates. For example, within right-sided tumors,
mutations decreased from 70% for cecal, to 43% for hepatic flexure location (
= 0.0001), while
V600 mutations increased from 10% to 22% between the same locations (
< 0.0001). Within left-sided tumors, the sigmoid and rectal region had more
mutations (
= 0.027), less
(
= 0.0009),
(
= 0.0033), or
mutations (
< 0.0001), and less MSI (
< 0.0001) than other left-sided locations. Despite this, a left/right division preceding the transverse colon maximized prognostic differences by side and transverse colon tumors had K-modes mutation clustering that appeared more left than right sided. CMS profiles showed a decline in CMS1 and CMS3 and rise in CMS2 prevalence moving distally.
Current right/left classifications may not fully recapitulate regional variations in tumor biology. Specifically, the sigmoid-rectal region appears unique and the transverse colon is distinct from other right-sided locations.
.
Impaired insulin-mediated suppression of hepatic glucose production (HGP) plays a major role in the pathogenesis of type 2 diabetes (T2D), yet the molecular mechanism by which this occurs remains ...unknown. Using a novel in vivo metabolomics approach, we show that the major mechanism by which insulin suppresses HGP is through reductions in hepatic acetyl CoA by suppression of lipolysis in white adipose tissue (WAT) leading to reductions in pyruvate carboxylase flux. This mechanism was confirmed in mice and rats with genetic ablation of insulin signaling and mice lacking adipose triglyceride lipase. Insulin’s ability to suppress hepatic acetyl CoA, PC activity, and lipolysis was lost in high-fat-fed rats, a phenomenon reversible by IL-6 neutralization and inducible by IL-6 infusion. Taken together, these data identify WAT-derived hepatic acetyl CoA as the main regulator of HGP by insulin and link it to inflammation-induced hepatic insulin resistance associated with obesity and T2D.
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•Insulin inhibits gluconeogenesis by suppressing lipolysis and hepatic acetyl CoA•Hyperglycemia associated with HFD is due to increased WAT-derived hepatic acetyl CoA•ATGL KOs are protected from HFD-induced insulin resistance due to decreased lipolysis•mφJNK KOs are protected from HFD-induced insulin resistance due to decreased lipolysis
Metabolic abnormalities associated with a high-fat diet are found to be driven by increased hepatic acetyl CoA levels, which are shown to be a consequence of white adipose tissue inflammation and inappropriately increased lipolysis.
Background
Colorectal cancer (CRC) incidence is increasing in adults younger than 50 years. This study evaluated clinical and molecular features to identify those features unique to early‐onset CRC ...that differentiate these patients from patients 50 years old or older.
Methods
Baseline characteristics were evaluated according to the CRC onset age with 3 independent cohorts. A fourth cohort was used to describe the impact of age on the consensus molecular subtype (CMS) prevalence.
Results
This retrospective review of more than 36,000 patients with CRC showed that early‐onset patients were more likely to have microsatellite instability (P = .038), synchronous metastatic disease (P = .009), primary tumors in the distal colon or rectum (P < .0001), and fewer BRAF V600 mutations (P < .001) in comparison with patients 50 years old or older. Patients aged 18 to 29 years had fewer adenomatous polyposis coli (APC) mutations (odds ratio OR, 0.56; 95% confidence interval CI, 0.35‐0.90; P = .015) and an increased prevalence of signet ring histology (OR, 4.89; 95% CI, 3.23‐7.39; P < .0001) in comparison with other patients younger than 50 years. In patients younger than 40 years, CMS1 was the most common subtype, whereas CMS3 and CMS4 were uncommon (P = .003). CMS2 was relatively stable across age groups. Early‐onset patients with inflammatory bowel disease were more likely to have mucinous or signet ring histology (OR, 5.54; 95% CI, 2.24‐13.74; P = .0004) and less likely to have APC mutations (OR, 0.24; 95% CI, 0.07‐0.75; P = .019) in comparison with early‐onset patients without predisposing conditions.
Conclusions
Early‐onset CRC is not only distinct from traditional CRC: special consideration should be given to and further investigations should be performed for both very young patients with CRC (18‐29 years) and those with predisposing conditions. The etiology of the high rate of CMS1 in patients younger than 40 years deserves further exploration.
Early‐onset colorectal cancer (at an age <50 years) has distinct clinical and molecular features, including increased prevalences of synchronous metastatic disease, microsatellite instability, primary tumors located in the distal colon or rectum, and consensus molecular subtype 1 and fewer mutations in BRAF V600, in comparison with colorectal cancer in patients older than 50 years. Among patients with early‐onset colorectal cancer, those aged 18 to 29 years and those with predisposing conditions are distinct from the other patients younger than 50 years, and this suggests that considering all patients with colorectal cancer younger than 50 years together may not be appropriate.
Current interest in melanin films derived from the autoxidation of dopamine stems from their use as a universal adhesion layer. Here we report chemical and physical characterization of polydopamine ...films deposited on gold surfaces from stirred basic solutions at times ranging from 2 to 60 min, with a focus on times ≤10 min. Data from Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and electrochemical methods suggest the presence of starting (dopamine) and intermediate (C=N-containing tautomers of quinone and indole) species in the polydopamine films at all deposition times. A uniform overlayer analysis of the XPS data indicates that film thickness increased linearly at short deposition times of ≤10 min. At deposition times ≥10 min, the films appeared largely continuous with surface roughness ≈ ≤ 2 nm, as determined by atomic force microscopy (AFM). Pinhole-free films, as determined by anionic redox probe measurements, required deposition times of 60 min or greater.
Beyond fossil fuel-driven nitrogen transformations Chen, Jingguang G; Crooks, Richard M; Seefeldt, Lance C ...
Science (American Association for the Advancement of Science),
05/2018, Letnik:
360, Številka:
6391
Journal Article
Recenzirano
Odprti dostop
Nitrogen is fundamental to all of life and many industrial processes. The interchange of nitrogen oxidation states in the industrial production of ammonia, nitric acid, and other commodity chemicals ...is largely powered by fossil fuels. A key goal of contemporary research in the field of nitrogen chemistry is to minimize the use of fossil fuels by developing more efficient heterogeneous, homogeneous, photo-, and electrocatalytic processes or by adapting the enzymatic processes underlying the natural nitrogen cycle. These approaches, as well as the challenges involved, are discussed in this Review.
Evolving treatments, disease phenotypes, and biology, together with a changing drug development environment, have created the need to revise castration-resistant prostate cancer (CRPC) clinical trial ...recommendations to succeed those from prior Prostate Cancer Clinical Trials Working Groups.
An international expert committee of prostate cancer clinical investigators (the Prostate Cancer Clinical Trials Working Group 3 PCWG3) was reconvened and expanded and met in 2012-2015 to formulate updated criteria on the basis of emerging trial data and validation studies of the Prostate Cancer Clinical Trials Working Group 2 recommendations.
PCWG3 recommends that baseline patient assessment include tumor histology, detailed records of prior systemic treatments and responses, and a detailed reporting of disease subtypes based on an anatomic pattern of metastatic spread. New recommendations for trial outcome measures include the time to event end point of symptomatic skeletal events, as well as time to first metastasis and time to progression for trials in the nonmetastatic CRPC state. PCWG3 introduces the concept of no longer clinically benefiting to underscore the distinction between first evidence of progression and the clinical need to terminate or change treatment, and the importance of documenting progression in existing lesions as distinct from the development of new lesions. Serial biologic profiling using tumor samples from biopsies, blood-based diagnostics, and/or imaging is also recommended to gain insight into mechanisms of resistance and to identify predictive biomarkers of sensitivity for use in prospective trials.
PCWG3 moves drug development closer to unmet needs in clinical practice by focusing on disease manifestations most likely to affect prognosis adversely for therapeutics tested in both nonmetastatic and metastatic CRPC populations. Consultation with regulatory authorities is recommended if a trial is intended to seek support for drug approval.
Prostate-specific membrane antigen (PSMA) is of considerable interest as a target for diagnostics and therapy of prostate cancer patients. PSMA-targeted imaging has demonstrable value in guiding the ...management of the clinical evolution of prostatic cancer. The use of PSMA-targeted therapy using
Lu-labeled PSMA-617 is similarly effective and is progressing toward approval. The phase III VISION trial represents the largest well-designed and executed study of a theranostic pair. This article provides an overview of the phase III trial and delineates the different study arms and their implications in the assessment of efficacy. The VISION (phase III) trial will provide data of critical value to the field of theranostics and especially the field of prostatic cancer management.
Guiding the beta-emitting isotope lutetium-177 to prostate cancer lesions with the prostate-specific membrane antigen–targeted radioligand
177
Lu-PSMA-617 plus using standard care was compared with ...standard care in patients with metastatic castration-resistant prostate cancer. The radioligand therapy prolonged progression-free and overall survival. Adverse effects were more common, but quality of life was maintained.
Summary Background MDV3100 is an androgen-receptor antagonist that blocks androgens from binding to the androgen receptor and prevents nuclear translocation and co-activator recruitment of the ...ligand-receptor complex. It also induces tumour cell apoptosis, and has no agonist activity. Because growth of castration-resistant prostate cancer is dependent on continued androgen-receptor signalling, we assessed the antitumour activity and safety of MDV3100 in men with this disease. Methods This phase 1–2 study was undertaken in five US centres in 140 patients. Patients with progressive, metastatic, castration-resistant prostate cancer were enrolled in dose-escalation cohorts of three to six patients and given an oral daily starting dose of MDV3100 30 mg. The final daily doses studied were 30 mg (n=3), 60 mg (27), 150 mg (28), 240 mg (29), 360 mg (28), 480 mg (22), and 600 mg (3). The primary objective was to identify the safety and tolerability profile of MDV3100 and to establish the maximum tolerated dose. The trial is registered with ClinicalTrials.gov , number NCT00510718. Findings We noted antitumour effects at all doses, including decreases in serum prostate-specific antigen of 50% or more in 78 (56%) patients, responses in soft tissue in 13 (22%) of 59 patients, stabilised bone disease in 61 (56%) of 109 patients, and conversion from unfavourable to favourable circulating tumour cell counts in 25 (49%) of the 51 patients. PET imaging of 22 patients to assess androgen-receptor blockade showed decreased18 F-fluoro-5α-dihydrotestosterone binding at doses from 60 mg to 480 mg per day (range 20–100%). The median time to progression was 47 weeks (95% CI 34–not reached) for radiological progression. The maximum tolerated dose for sustained treatment (>28 days) was 240 mg. The most common grade 3–4 adverse event was dose-dependent fatigue (16 11% patients), which generally resolved after dose reduction. Interpretation We recorded encouraging antitumour activity with MDV3100 in patients with castration-resistant prostate cancer. The results of this phase 1–2 trial validate in man preclinical studies implicating sustained androgen-receptor signalling as a driver in this disease. Funding Medivation, the Prostate Cancer Foundation, National Cancer Institute, the Howard Hughes Medical Institute, Doris Duke Charitable Foundation, and Department of Defense Prostate Cancer Clinical Trials Consortium.
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