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Biomedical subjects

P Sparks

Publications and source records attributed to P Sparks.

13 recordsLinked to original sources
PubMed2001

Mucin MUC1 is seen in cell surface protrusions together with ezrin in immunoelectron tomography and is concentrated at tips of filopodial protrusions in MCF-7 breast carcinoma cells.

MUC1, a transmembrane member of the mucin family, is believed to have anti-adhesive properties because of its highly sialylated, extended, and rigid rod-like conformation. The ERM proteins (ezrin, radixin, and moesin) function as membrane-cytoskeletal linkers. MUC1 and ezrin are enriched in microvilli in MCF-7az breast carcinoma cells. Similar localization was also found in peripheral membrane areas and in filopodium-like protrusions. Whereas ezrin was consistently detected in the cell-cell contact region, MUC1 was less frequently found there. MUC1 was distinctly expressed in long filopodial protrusions and was highly concentrated at their tips, which also contained ezrin, whereas F-actin was found along the stalk. This localization of MUC1 suggests a role for MUC1 in transient cell structures of migrating cells and transient cell adhesion. No direct association has yet been found between MUC1 and ezrin. However, both MUC1 and ezrin had a similar overall distribution pattern in microvilli and filopodium-like protrusions in immunoelectron tomography. In addition, MUC1 and ezrin showed spatial association, because several 10-nm gold particles used to decorate ezrin were seen in the vicinity close to the clusters of 5-nm gold particles decorating MUC1. Therefore, MUC1 appears to be associated with ezrin, but the nature of this association requires further study.

Cytoskeletal Proteins↗
PubMed2001

Ambivalence about health-related behaviours: an exploration in the domain of food choice.

OBJECTIVES: Interest in attitudes and ambivalence has highlighted problems with the adequacy of conceptualizing attitudes as unitary, unidimensional, evaluations. In this paper, we report an application of the Theory of Planned Behaviour (Ajzen, 1991) in the domain of dietary choice which investigates the hypothesis that ambivalence will attenuate observed attitude-intention relationships (since the evaluations influencing the expression of attitudes are more likely to differ from the evaluations influencing the expression of intentions for people who are more ambivalent. DESIGN: Participants completed a postal questionnaire which contained, inter alia, measures assessing the components of the Theory of Planned Behaviour and a measure of ambivalence. METHODS: Participants (N = 296) were recruited via advertisements placed in local newspapers, asking for volunteers to assist in a research project. Participants were randomly assigned to complete a questionnaire about either their chocolate consumption or their meat consumption. Participants were paid 4. RESULTS: The findings show considerable support for the hypothesis: there was a tendency for attitude-intention relationships to be attenuated among participants with higher levels of ambivalence, compared to participants with lower levels of ambivalence. CONCLUSIONS: The research supports the widespread view that ambivalence is an important issue, both for those involved in basic attitude research and for those who seek to use attitude theories in applied research. In particular, the findings indicate that ambivalence may often have implications for the predictive ability of attitude-intention-behaviour models, especially when applied to health-related behaviours that are characterized by motivational conflicts.

Journal Article↗
PubMed1999

The effects of providing personalized dietary feedback. A semi-computerized approach.

There not only seems to be a trend for people to underestimate the dietary risks that they face, but it appears that this underestimation may be related to the difficulties they encounter when trying to assess their own dietary intake. A study (n = 118) examining the effects of providing people with information about their own dietary fat intake on their attitudes towards dietary change and their subsequent fat consumption is described. Participants in a group receiving feedback about their fat intake did not decrease their consumption of fat more than did those in a control group. No effects on subsequent fat consumption were observed in a group who had higher than average levels of fat consumption, higher perceived fat consumption than actual fat consumption and who received feedback information about their fat consumption. The results are discussed in relation to their implications for health promotion strategies that focus on the motivational effects of providing people with information about their fat consumption.

Attitude to Health↗
PubMed1999

A critical examination of the application of the Transtheoretical Model's stages of change to dietary behaviours.

This paper proposes that the application of the Transtheoretical Model's stages of change to dietary behaviours may be fundamentally problematic due to the difference in nature between dietary behaviours and the addictive behaviours upon which the model was originally based. It was considered that specific problems associated with stage categorization for dietary change would include: problems due to the potential mismatch between a person's perceived and actual dietary behaviour; and problems due to the use of specific time periods to distinguish between different stages. A total of 541 volunteers completed questionnaires that measured their stage of change with respect to one of three dietary behaviours (healthy eating, eating a low-fat diet, and eating five portions of fruit and vegetables per day). Results indicate that people who were actively making a change (actors) or maintaining a change (maintainers) had done so for a range of different periods of time, with no specific cut-off point being evident. Also, more realistic stage categorizations were evident for the most specific dietary behaviours where there was least likelihood of a mismatch between perceived and actual dietary behaviour. Problems associated with issues of operationalization of the model and the application of the stage model to dietary change are discussed.

Adolescent↗
PubMed1998

Interpretations of healthy and unhealthy eating, and implications for dietary change.

Central to many considerations of health-related dietary change is the interpretation given to 'healthy' and 'unhealthy' eating. Results are reported from two studies which investigated people's understanding of these concepts. The first study involved structured interviews with 48 respondents: a wide range of interpretations of healthy and unhealthy eating was found using content analysis techniques. The second study (n = 242) used questionnaires to assess the extent to which different interpretations were endorsed. The extent to which different eating behaviours were perceived as healthy or unhealthy varied greatly. A principal components analysis of perceptions of healthy and unhealthy eating produced five separate factors. Some differences in perceptions were found for people of different age, gender and educational level. Objectively assessed dietary intake and perceived intake were found to be two distinct quantities. 'Healthy' eaters were found to perceive 'healthy eating' slightly differently to 'unhealthy' eaters. The results suggest that lay understanding of healthy eating does generally conform with dietary guidelines, and therefore health promotion priorities should focus on physical and psychological constraints to healthy eating, rather than attempting to increase the public's knowledge as a whole.

Adolescent↗
PubMed1995

Perceived behavioural control, unrealistic optimism and dietary change: an exploratory study.

In the context of five dietary changes conducive to reductions in fat consumption, a short questionnaire was constructed to examine the applicability of the theory of planned behaviour and to assess the presence of the phenomenon of "unrealistic optimism". An extension to the theory of planned behaviour was also included, in the form of a "self-identity" measure assessing identification with concern about the health consequences of diet. The questionnaire was completed by 612 members of the general public at three different locations in the U.K. The findings indicate some support for the applicability of the theory of planned behaviour, with the measure of "self-identity" producing some additional independent effects. Evidence of unrealistic optimism concerning diet-related health risks was found, with greater optimism being significantly related to lower relative consumption estimates of "unhealthy" foods. The findings are discussed in the context of implications for health promotion.

Adolescent↗
PubMed1994

Public perceptions of the potential hazards associated with food production and food consumption: an empirical study.

Although public perceptions of food-related hazards receive much media comment and debate, the research literature on such perceptions is sparse and piecemeal. In the reported study, 216 people completed a questionnaire relating to their perceptions of the "risk characteristics" of potential hazards associated with various aspects of food production and food consumption. Responses were examined via principal-components analysis to obtain a structural representation of risk perception of the kind provided by Fischhoff, Slovic, and their colleagues in their seminal psychometric work. A three-component solution accounting for 87% of the variance was obtained, with the dimensions labeled as "severity," "unknown," and "number of people exposed." The findings also yielded information pointing to evidence of the phenomenon of unrealistic optimism. We conclude that our findings offer a useful base upon which further in-depth research integrating different perspectives on risk perception with respect to food-related hazards may be developed.

Analysis of Variance↗
PubMed1990

Clinical and immunologic evaluation of 37 workers exposed to gaseous formaldehyde.

Thirty-seven workers exposed to formaldehyde (F) were evaluated to determine whether any of their respiratory or ocular symptoms were mediated by an immunologic response to F. Because there has never been a case of defined immunologically mediated respiratory or ocular disease as a result of exposure to gaseous F, we used clinical and immunologic criteria developed for immunologic respiratory diseases that result from inhalational exposure to trimellitic anhydride. A clinical assessment included review of a medical summary of history, physical examination, chest x-ray films, and pulmonary function studies. Serologic assessment was made with an ELISA for IgE and IgG to F human serum albumin. The final evaluation for immunologically mediated disease was based on both the clinical and serologic assessments. None of the workers had IgE or IgG antibody to F-human serum albumin or an immunologically mediated respiratory or ocular disease caused by F; however, some of the workers appeared to experience irritant symptoms caused by workplace exposure to F or other irritant chemicals.

Adult↗