Biomedical subjects

Robert Latour

Publications and source records attributed to Robert Latour.

4 recordsLinked to original sources

PubMed2006

Selective protein adsorption on a phase-separated solvent-cast polymer blend.

Polymer-based biomedical devices are growing increasingly sophisticated as compositions evolve toward copolymers and blends in order to satisfy complex design criteria. Such polymers afford opportunities for both micro- and macrophase separation at nano- and micro-length scales and raise questions concerning the role of heterogeneous surface morphology on protein adsorption. Adsorbed protein layers play a critical role in mediating the interaction of cells with polymer surfaces, and both understanding and controlling protein adsorption is assuming greater significance in the development of surfaces with enhanced physiological compatibility. Here we study the short-time adsorption of ferritin, a model protein highly resistant to denaturation and easily imaged in the transmission electron microscope (TEM), onto a phase-separated homopolymer blend of polycaprolactone (PCL) and a polycarbonate derived from desaminotyrosyl-tyrosine dodecyl ester (PDTD). At physiological pH, ferritin selectively adsorbs onto the PDTD phase at a surface density approximately three times greater than that on the PCL phase. By decreasing the pH below ferritin's isoelectric point so its average charge becomes positive, the selective adsorption disappears and the surface density of adsorbed ferritin becomes independent of the phase separation. We attribute the selectivity to the electrostatic repulsion between ferritin and hydrolytically charged PCL, both of which will have a net negative charge at physiological pH. To perform these experiments, we solvent-cast ultrathin polymer films onto dissolvable salt substrates, and we characterize the morphology by TEM imaging and quantitative spatially resolved electron energy-loss spectroscopy (EELS). We find that the film morphology depends strongly on such processing-related variables as the solvent evaporation rate and the nature of the surface in contact with the polymer film during casting. The adsorption of ferritin depends on whether the film is phase-separated as well as to which surface of the film the protein solution is exposed, and these findings suggest that seemingly small variations in polymer processing that influence both the bulk and surface morphology can have a profound effect on the short-time protein adsorption.

Adsorption↗

PubMed2005

The diversity of prevention and health promotion services offered by Québec Community Health Centres: a study of infant and toddler programmes.

Research has shown that preventive and health promotion (PHP) services offered by community health centres are often vulnerable in times of health reform or budgetary cutbacks. The present study was conducted in Québec, Canada, approximately 10 years after the start of a major transformation of health care services. The objectives were: (1) to examine the diversity of infant/toddler prevention and health promotion services offered by centres locaux de services communautaires (CLSCs, local community health and social services centres); and (2) to investigate the organisational and environmental correlates of such diversity. All Québec CLSCs were invited to complete a survey questionnaire regarding their PHP services (response rate = 69%). Data on environmental and organisational factors were extracted from existing Québec government data sets. Bivariate and multivariate analyses were performed to identify the correlates of the CLSCs' level of diversity of PHP services. The results revealed that CLSCs varied greatly in terms of their diversity of PHP services. The number of full-time equivalents in the Child and Family Services Programme (one of two programmes aimed at reaching the targeted clientele) and the degree of CLSC collaboration with other community-based organisations in the planning and delivery of PHP activities were positively associated with the level of diversity, whereas the unemployment rate in the population served was a negative predictor. This study makes an important contribution in being one of the very few which contribute to building our knowledge about the performance of community health centres. Identifying the correlates of diversity among PHP services offered by CLSCs helps us to begin to understand the processes at work in the production of PHP activities, as well as the potential leveraging forces.

Child Health Services↗

PubMedDate not supplied

[The preventive and health promotion services for infants, children and youth. What is problematic for clients of the CLSCs].

OBJECTIVE: This article presents the results of a survey on preventive and health promotion (PHP) services provided by Quebec CLSCs for infants, children and youth. Two dimensions of services are examined: the diversity of PHP issues addressed and the type of clientele targeted by the CLSC team. METHODS: Questionnaire survey. RESULTS: Although identified a priori as public health priorities, many PHP issues remain less often addressed by CLSCs. This is particularly the case for activities aimed at children and youth as compared to infants. In addition, the data show that CLSC teams are less inclined to target specific clienteles; when they do so, it is more often in the context of services for infants. DISCUSSION: This study is important in that it constitutes one of the first efforts to systematically document PHP services for infants, children, and youth. In shedding new light on intervention sectors that need to be reinforced, these results should help managers and policymakers as they reflect on the role of PHP services in CLSCs within the context of health reform.

Adolescent↗

PubMedDate not supplied

[Breastfeeding promotion and support services in local community health centers].

This study had a two-fold goal. First, to document services relating to breastfeeding promotion and support in CLSCs and, second, to examine the links between the delivery of such services and certain organizational and environmental factors. The data were collected in 1999 by means of a self-administered questionnaire sent to all CLSCs in Quebec. The responses indicated that breastfeeding is most often systematically addressed at prenatal meetings and through integrated perinatal programs. CLSCs belonging to a multipurpose establishment are more apt to integrate the issue of breastfeeding into perinatal activities; in addition, many of them offer breastfeeding activities considered innovative, although the average for this kind of activities is fairly low (33%). In addition, CLSCs that collaborate more closely with community organizations and those that spend more on perinatal programs are the ones that most often offer "innovative" breastfeeding activities.

Breast Feeding↗