Edinburgh Napier University

About: Edinburgh Napier University is a education organization based out in Edinburgh, United Kingdom. It is known for research contribution in the topics: Population & Health care. The organization has 2665 authors who have published 6859 publications receiving 175272 citations.

Senescent T-lymphocytes are mobilised into the peripheral blood compartment in young and older humans after exhaustive exercise.

Abstract: Senescent T-lymphocytes are antigen-experienced cells that express the killer-cell lectin-like receptor G1 (KLRG1) and/or CD57; fail to clonally expand following further antigenic stimulation and prevail in the resting blood of older adults compared to the young. Physical exercise mobilises T-lymphocytes into the bloodstream and is therefore a model with which to compare age-related phenotypes of blood-resident T-cells with those T-cells entering the blood from peripheral lymphoid compartments. Eight young (Y; Age: 21+/-3 years) and 8 older (O; Age: 56+/-3 years) healthy males completed a maximal treadmill exercise protocol. Blood lymphocytes isolated before, immediately after and 1h after exercise were assessed for cell surface expression of KLRG1, CD57, CD28, CD45RA, CD45RO, CD62L and lymphocyte subset markers using three-colour flow cytometry. Lymphocyte subset numbers (CD3+, CD3+/CD4+, CD3+/CD8 and CD3-/CD56+) increased with exercise (p<0.05) but were not different between Y and O. At rest and immediately after exercise, the percentage of CD3+/CD8+ T-lymphocytes expressing KLRG1 and CD45RO was greater in O than Y, whereas Y had a greater expression of CD45RA and CD62L than O. The percentage of all CD3+/CD8+ and CD3+/CD4+ T-lymphocytes expressing KLRG1 and CD57 increased after exercise, but the magnitude of change was not age-dependent. In conclusion, there is a greater proportion of senescent CD3+/CD8+ T-lymphocytes in the blood of older adults compared to young at rest and immediately after exhaustive exercise, indicating that the greater frequency of KLRG1+/CD8+ T-lymphocytes in older humans is ubiquitous and not localised to the peripheral blood.

Free radical activity of industrial fibers: role of iron in oxidative stress and activation of transcription factors.

Abstract: We studied asbestos, vitreous fiber (MMVF10), and refractory ceramic fiber (RCF1) from the Thermal Insulation Manufacturers' Association fiber repository regarding the following: free radical damage to plasmid DNA, iron release, ability to deplete glutathione (GSH), and activate redox-sensitive transcription factors in macrophages. Asbestos had much more free radical activity than any of the man-made vitreous fibers. More Fe3+ was released than Fe2+ and more of both was released at pH 4.5 than at pH 7.2. Release of iron from the different fibers was generally not a good correlate of ability to cause free radical injury to the plasmid DNA. All fiber types caused some degree of oxidative stress, as revealed by depletion of intracellular GSH. Amosite asbestos upregulated nuclear binding of activator protein 1 transcription factor to a greater level than MMVF10 and RCF1; long-fiber amosite was the only fiber to enhance activation of the transcription factor nuclear factor kappa B (NF kappa B). The use of cysteine methyl ester and buthionine sulfoximine to modulate GSH suggested that GSH homeostasis was important in leading to activation of transcription factors. We conclude that the intrinsic free radical activity is the major determinant of transcription factor activation and therefore gene expression in alveolar macrophages. Although this was not related to iron release or ability to deplete macrophage GSH at 4 hr, GSH does play a role in activation of NF kappa B.

When are summary ROC curves appropriate for diagnostic meta‐analyses?

Abstract: Diagnostic tests are increasingly evaluated with systematic reviews and this has lead to the recent developments of statistical methods to analyse such data. The most commonly used method is the summary receiver operating characteristic (SROC) curve, which can be fitted with a non-linear bivariate random-effects model. This paper focuses on the practical problems of interpreting and presenting data from such analyses. First, many meta-analyses may be underpowered to obtain reliable estimates of the SROC parameters. Second, the SROC model may be inappropriate. In these situations, a summary with two univariate meta-analyses of the true and false positive rates (TPRs and FPRs) may be more appropriate. We characterize the type of problems that can occur in fitting these models and present an algorithm to guide the analyst of such studies, with illustrations from analyses of published data. A set of R functions, freely available to perform these analyses, can be downloaded from (www.diagmeta.info).