Search results for "Regression analysis"
showing 10 items of 807 documents
Identifying Prognostic SNPs in Clinical Cohorts: Complementing Univariate Analyses by Resampling and Multivariable Modeling
2016
Clinical cohorts with time-to-event endpoints are increasingly characterized by measurements of a number of single nucleotide polymorphisms that is by a magnitude larger than the number of measurements typically considered at the gene level. At the same time, the size of clinical cohorts often is still limited, calling for novel analysis strategies for identifying potentially prognostic SNPs that can help to better characterize disease processes. We propose such a strategy, drawing on univariate testing ideas from epidemiological case-controls studies on the one hand, and multivariable regression techniques as developed for gene expression data on the other hand. In particular, we focus on …
Prognostic impact and implications of extra-capsular lymph node involvement in colorectal cancer: a systematic review with meta-analysis.
2015
The extranodal extension (ENE) of nodal metastasis (i.e. the extension of tumor cells through the nodal capsule into the perinodal adipose tissue) has recently emerged as an important prognostic factor in different types of malignancies. However, the tumor-node-metastasis (TNM) staging system for colorectal cancer does not consider it as a prognostic parameter. Therefore, we conducted a systematic review and meta-analysis to determine the prognostic role of ENE in patients with lymph node-positive colorectal cancer.Two independent authors searched PubMed and SCOPUS until 7 January 2015 without language restrictions. Prospective studies reporting data on prognostic parameters in subjects wit…
Molecular topology: A new strategy for antimicrobial resistance control
2017
The control of antimicrobial resistance (AMR) seems to have come to an impasse. The use and abuse of antibacterial drugs has had major consequences on the genetic mutability of both pathogenic and nonpathogenic microorganisms, leading to the development of new highly resistant strains. Because of the complexity of this situation, an in silico strategy based on QSAR molecular topology was devised to identify synthetic molecules as antimicrobial agents not susceptible to one or several mechanisms of resistance such as: biofilms formation (BF), ionophore (IA) activity, epimerase (EI) activity or SOS system (RecA inhibition). After selecting a group of 19 compounds, five of them showed signific…
Stagewise pseudo-value regression for time-varying effects on the cumulative incidence
2015
In a competing risks setting, the cumulative incidence of an event of interest describes the absolute risk for this event as a function of time. For regression analysis, one can either choose to model all competing events by separate cause-specific hazard models or directly model the association between covariates and the cumulative incidence of one of the events. With a suitable link function, direct regression models allow for a straightforward interpretation of covariate effects on the cumulative incidence. In practice, where data can be right-censored, these regression models are implemented using a pseudo-value approach. For a grid of time points, the possibly unobserved binary event s…
Search of Chemical Scaffolds for Novel Antituberculosis Agents
2005
3 A method to identify chemical scaffolds potentially active against Mycobacterium tuberculosis is presented. The molecular features of a set of structurally heterogeneous antituberculosis drugs were coded by means of structural invariants. Three tech- niques were used to obtain equations able to model the antituberculosis activity: linear discriminant analysis, multilinear re- gression, and shrinkage estimation-ridge regression. The model obtained was statistically validated through leave-n-out test, and an external set and was applied to a database for the search of new active agents. The selected compounds were assayed in vitro, and among those identified as active stand reserpine, N,N,N…
Revealing the relationship between vegetable oil composition and oxidative stability: A multifactorial approach
2018
Abstract A detailed composition analysis was performed for 22 diverse oils and fats and included determination of tocopherols (α, γ and δ), β-carotene, chlorophyll, total phenolic compounds (TPC) and fatty acid (FA) composition, as well as the determination of their oxidative stability (Rancimat test). Principal components analysis was applied to obtain an overview of the sample variations and to identify behavioural patterns. Linear regression correlations and a multiple linear regression model were performed to quantify the relationship between the composition of oils and fats and their oxidative stability. The TPC and saturated FA were the main individual factors that correlated positive…
Does endogenous serum oestrogen play a role in meibomian gland dysfunction in postmenopausal women with dry eye?
2016
Aim To explore the relationship between serum concentration of sex hormones and dry eye symptoms and signs in postmenopausal women. Methods A cross-sectional analysis was undertaken. Subjects were 46 postmenopausal women with dry eye (mean age 64.4±5.2 years, 13.7±6.4 years since menopause; not undergoing hormone replacement therapy). Ocular symptoms (Ocular Surface Disease Index (OSDI) and Ocular Comfort Index (OCI)), tear function (tear osmolarity, non-invasive tear break-up time, tear secretion), corneal and conjunctival staining, and meibomian gland (MG) appearance, were recorded. Venous blood was collected and serum concentrations of 17β-oestradiol (E2), 3-α-androstanediol-glucuronide …
Iron Status of Vegans, Vegetarians and Pescatarians in Norway
2021
Although plant-based diets provide well-established physical and environmental health benefits, omitting meat or meat products has also been associated with a risk of being deficient in specific nutrients, such as iron. As data on the iron status among Norwegian vegans, vegetarians and pescatarians are lacking, the present study aimed to assess iron status in these groups of healthy adults. Blood markers for iron status were measured in 191 participants (18–60 years old) comprising 106 vegans, 54 vegetarians and 31 pescatarians: serum-ferritin (S-Fe), serum-iron (S-Iron) and serum-total iron binding capacity (S-TIBC). Serum-transferrin-saturation (S-TSAT) was estimated (S-Iron/S-TIBC × 100)…
Ferritin and C-reactive protein are predictive biomarkers of mortality and macrophage activation syndrome in adult onset Still's disease. Analysis of…
2020
ObjectiveTo assess the predictive role of ferritin and C-reactive protein (CRP) on occurrence of macrophage activation syndrome (MAS) and mortality in patients with adult onset Still's disease (AOSD), a rare and severe disease, included in the multicentre Gruppo Italiano di Ricerca in Reumatologia Clinica e Sperimentale (GIRRCS) cohort.MethodsThe predictive role, at the time of diagnosis, of serum levels of ferritin and CRP on occurrence of MAS and mortality, was evaluated by logistic regression analyses and receiver-operating characteristic (ROC) curves were built to identify patients at high risk of MAS and mortality, respectively.ResultsIn assessed 147 patients with AOSD, levels of ferri…
THU0520 Assessment of cardiovascular risk in patients with fibromyalgia by carotid-femoral pulse wave velocity – results of a prospective study
2018
Background Autonomic dysfunction, a basic element of fibromyalgia (FM), has been in some cases related to increased risk of cardiovascular (CV) disease. CV risk associates with aortic stiffness, which can be reliably assessed by carotid-femoral pulse wave velocity (cfPWV). Objectives Aims of this study were to test the hypothesis of increased cfPWV in a group of patients with FM and to examine its association with FM associated parameters and selected traditional CV risk factors. Methods We performed measurements of cfPWV in 99 FM patients and 102 healthy controls. The difference between cfPWV values in the two groups after controlling for possible confounding factors was evaluated through …