PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 10028138

Two-state mixed renewal processes for chronic disease.

R J Cook·E T Ng·J Mukherjee·D Vaughan
View original source ↗Export metadata ↓

Abstract

We develop a model based on a two-state mixed renewal process and propose its use for modelling disease activity in studies of chronic conditions. We specify Weibull forms for the conditional transition intensities to allow for time trends, and bivariate frailties to accommodate subject-to-subject variability in the disease process. Extensions of this model are considered for stratified analyses in which strata are defined by the number of past exacerbations. Data from a motivating study of chronic bronchitis are analysed to illustrate the methodology.

Explore related subjects

Anti-Infective AgentsBronchitisChronic DiseaseCiprofloxacinHumansLikelihood FunctionsModels, BiologicalMulticenter Studies as TopicRandomized Controlled Trials as TopicRegression AnalysisRisk FactorsStochastic ProcessesClinical TrialJournal ArticleRandomized Controlled TrialResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

R J Cook, E T Ng, J Mukherjee, D Vaughan. 1999-01-30. Two-state mixed renewal processes for chronic disease.. https://doi.org/10.1002/(sici)1097-0258(19990130)18%3A2%3C175%3A%3Aaid-sim997%3E3.0.co%3B2-b

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Chemical composition and antimicrobial activity of volatile compounds of Tamarix boveana (Tamaricaceae).

The chemical composition of the Tamarix boveana volatile oils obtained from the whole aerial part, flowers, leaves and stems by steam distillation was analysed using gas chromatograph (GC)-flame ionization detectors (FID) and GC-MS. Sixty-two components were identified. Hexadecanoic acid (18.14%), docosane (13.34%), germacrene D (7.68%), fenchyl acetate (7.34%), Benzyl benzoate (4.11%) were found to be the major components in the whole aerial parts. This composition differed according to the tested part: 2.4 Nonadienal was the main compound in the flowers (12.13%) while germacrene D was the major component in leaves (31.43%) and hexadecanoic acid in the stems (13.94%). To evaluate in vitro antimicrobial activity, all volatile oils were tested against six Gram-positive and Gram-negative bacteria and four fungi. The T. boveana volatile oils exhibited an interesting antibacterial activity against all strains tested except Pseudomonas aeruginosa but no antifungal activity was detected.

Anti-Infective Agents↗
PubMed2007

Role of human neutrophil peptides in the initial interaction between lung epithelial cells and CD4+ lymphocytes.

Human neutrophil peptides (HNP) exert immune-modulating effects. We hypothesized that HNP link innate and adaptive immunity through activation of costimulatory molecules. Human lung epithelial cells and CD4+ lymphocytes were treated with HNP separately or in coculture. Stimulation with HNP induced an increase in cell surface expression of CD54 (ICAM-1), CD80, and CD86 on lung epithelial cells and the corresponding major ligands, CD11a (LFA-1), CD152 (CTLA-4), and CD28 on CD4+ lymphocytes. There was an increased nuclear expression of the transcription factor p53 in human alveolar A549 cells and an elevated NF-kappaB (p50) and a degradation of I-kappaB protein in CD4+ lymphocytes following HNP stimulation. HNP enhanced the interaction between A549 cells and CD4+ lymphocytes by increasing cell adhesion and release of IFN-gamma, IL-2, and IL-8. This was attenuated by using an alpha1-proteinase inhibitor to neutralize HNP. We conclude that HNP play an important role in linking innate to acquired immunity by activation of costimulatory molecules in lung epithelial cells and CD4+ lymphocytes.

Anti-Infective Agents↗