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J Wyse

Publications and source records attributed to J Wyse.

4 recordsLinked to original sources
PubMed1995

Evidence for the validity and utility of the Stages of Exercise Behaviour Change scale in young adults.

This study examined the validity and utility of the Stages of Exercise Behaviour Change (SEBC) scale in 244 young British adults. One-way ANOVA revealed significant differences (F > 7.34, P < 0.01) between the Exercise Behaviour Change Categories of Precontemplation/Contemplation (n = 49), Preparation (n = 87) and Action/Maintenance (n = 108) in self-report levels of exercise behaviour. Significant differences (F > 3.14, P < 0.05) were also revealed in exercise self-efficacy, physical self-perception sub-domains and global self-esteem scores. Subsequent step-wise discriminant analyses revealed that discrimination between the Categories of Exercise Behaviour Change was possible on the basis of selected behavioural and psychological parameters (Canonical r = 0.76-0.82, Wilks' lambda = 0.30-0.33, chi 2 = 60.3-94.6, d.f. = 14, P < 0.0001). In both males and females, the most dominant discriminatory variables in the first Function were revealed to be perceived physical conditioning and 'strenuous' exercise behaviour. For males, the second Function comprised exercise self-efficacy and perceived bodily attractiveness, whilst for females it comprised perceived bodily attractiveness, perceived sports competence and perceived physical strength. Subsequent cross-validation analysis, using a randomly selected 40% sub-sample, revealed that 67.8-70.7% of subjects were assigned to the correct Category. These results appear to confirm the concurrent validity of the SEBC scale in terms of self-report of exercise behaviour. Furthermore, the utility of the SEBC scale was demonstrated via the ability to predict membership of specific Categories of Exercise Behaviour Change using a selection of behavioural and psychological parameters.

Adolescent↗
PubMed1991

Immunocytochemical analysis of glial cells in the hypomyelinated optic nerve of the BW mutant rat.

The Browman-Wyse (BW) rat is a mutant with structural defects of the visual system, including a failure of the proximal (retinal) end of the optic nerve to myelinate. This latter abnormality is correlated with an absence of CAII+ oligodendrocytes, but we have previously shown that astrocytes are normally distributed, as judged by morphological characteristics of GFAP+ cells in vivo. We have further examined in vitro the immunohistochemical characteristics of macroglia isolated from the BW optic nerve, either as cell suspensions or after 4 days in culture. Cell cultures derived from the hypomyelinated proximal segment of BW optic nerves contained very few 0-2A progenitor cells (from which oligodendrocytes and cells with the GFAP+/A2B5+ phenotype develop), whereas over 90% of the glia were Schwann cells. A proportion of these few 0-2A progenitor cells differentiated normally after 4 days in vitro into both progeny phenotypes in appropriate media. Accordingly, we conclude that the myelination deficiency in the BW optic nerve could be explained as a failure of 0-2A progenitor cells to populate fully the proximal extremity of the nerve during development. Since most glia isolated from adult optic nerves did not adhere to the culture substrate, we analysed the phenotypes of freshly isolated cells in suspension. Comparing optic nerves of normal adult rats with those of BW mutants, a significantly higher fraction of the GFAP+ cells reacted with A2B5 in cell suspensions of the latter. The double-labelled cells which are present in abnormally high numbers may be the differentiated progeny of 0-2A progenitors in the hypomyelinated segment of nerve. One explanation for these findings is that Schwann cells within the BW nerve induce the differentiation of 0-2A progenitor cells to the GFAP+/A2B5+ phenotype. We investigated this possibility using conditioned medium from cultured Schwann cells which increased tenfold the frequency of GFAP+/A2B5+ cells in normal neonatal rat optic nerve cultures. Oligodendrocyte numbers showed a concomitant decline with increasing concentration of Schwann cell conditioned medium. Hypomyelination in the BW rat optic nerve may therefore arise because Schwann cells, present in the proximal segment of the nerve, not only impede the migration of 0-2A progenitor cells but also release a factor which induces those 0-2A progenitor cells which arrive in the proximal segment of the nerve to differentiate into GFAP+ cells at a critical stage in oligodendrocyte development.

Animals↗