Models of osteoarthritis: the good, the bad and the promising.

Osteoarthritis (OA) is a chronic degenerative disease of diarthrodial joints most commonly affecting people over the age of forty. The causes of OA are still unknown and there is much debate in the literature as to the exact sequence of events that trigger the onset of the heterogeneous disease we recognise as OA. There is currently no consensus model for OA that naturally reflects human disease. Existing ex-vivo models do not incorporate the important inter-tissue communication between joint components required for disease progression and differences in size, anatomy, histology and biomechanics between different animal models makes translation to the human model very difficult. This narrative review highlights the advantages and disadvantages of the current models used to study OA. It discusses the challenges of producing a more reliable OA-model and proposes a direction for the development of a consensus model that reflects the natural environment of human OA. We suggest that a human osteochondral plug-based model may overcome many of the fundamental limitations associated with animal and in-vitro models based on isolated cells. Such a model will also provide a platform for the development and testing of targeted treatment and validation of novel OA markers directly on human tissues.

The Multiple Mini-Interview: A Possible Solution to Problems Associated with the Interview Processes for a Selected Entry Allied Health Program.

BACKGROUND: Concerns have been raised about the effectiveness of traditional semi-structured interviews in selected entry allied health programs in terms of whether they give applicants the best opportunity to demonstrate their personal qualities and whether the process itself is overly intimidating and impersonal. This in turn raises questions about the reliability and validity of interviews. In this study, a possible alternative process was examined, the multiple mini-interview (MMI). The study investigated the MMI's perceived acceptability for use by a speech-language pathology program. METHODS: The MMI was administered prior to the beginning of the academic year. The study involved 43 applicants and 5 faculty members. On completion of the MMI, participants were invited to complete an optional questionnaire about their perceptions of the process. CONCLUSIONS: Overall, applicants indicated that they found the MMI process to be fair, simple, and non-threatening. The faculty members who interviewed the students also indicated that the process was fairer than the traditional interview, easier for them to manage because they could focus on one specific aspect of the interview process, and gave them an opportunity to meet all of the applicants.

Situated learning in the practice placement.

Nurses who had just completed their training in Scotland were interviewed with regard to their experiences on placements. The nurses had either completed a traditional training course or came from the first cohort of the Project 2000 diploma level course. The interviews focused on the way in which the student nurses had learned in their practice placements. The results suggest that the placement is a complex social and cognitive experience in which there are elements of situated learning. Acceptance into the community of practice is important but this can be separated, conceptually at least, into a social acceptance which might be extended to any student and a professional acceptance which relies on the display of appropriate competence. The nurses described the way in which their mentors had interacted with them in terms which suggested that cognitive apprenticeship strategies had been used to further their learning in practice. It is concluded that, in view of the central importance of the placement for training nurses, explicit use of mentoring techniques derived from situated learning and cognitive apprenticeship might be beneficial.

Student reflective groups at a Scottish College of Nursing.

In this paper student views on reflective groups, set up as an important element of the new Project 2000 course in a Scottish College of Nursing, are reported. A random sample of 19 students were interviewed. While the reflective groups were very popular with students because they provided support, there was little evidence of a linkage between theory and practice. It was clear that the ambitious objective of stimulating reflection-on-action was not attained. Practice certainly was discussed, but it tended to be dominated by dramatic and emotionally charged aspects of care rather than the more frequent routine concerns. There were, however, indications that the original aim of the reflective groups could be achieved if tutors could establish a common understanding of the purpose of the groups and of reflection, and if the practices on which students reflected consisted less of single day visits where the students saw themselves as nonparticipant outsiders.

Situating theory in practice: student views of theory-practice in Project 2000 nursing programmes.

In this paper the views of student nurses taking Project 2000 at a Scottish College of Nursing are reported. A random sample of 19 students were interviewed. The interviews focused on the relationship between the college course and the students' experiences on placement. The majority had difficulty in relating the college course to their practice, except when it came to very specific parts of the programme, for example basic medical procedures. Only a minority could integrate the broader aspects of the course to their practice, largely because there was such a long period of time between studying a topic in college and the related placement. It is tempting to see the results as supporting the situated cognition hypothesis that theory loses meaning out of context, and it is evident, even from this limited study, that the success of Project 2000, with its emphasis on the 'knowledgeable doer', could depend, to a great extent, on the careful phasing of college coursework and placement to enable students to integrate theory and practice more effectively.

Antibodies against active-site peptides common to glucosyltransferases of mutans streptococci.

Polyclonal antibodies were raised against peptides derived from an active-site sequence common to the family of mutans streptococcal glucosyltransferases (GTFs). The sequence contains an aspartic acid residue that functions in formation of the enzyme transition state in catalysis. Two GTFs were targeted with similar but not identical sequences in this region: one that synthesizes an alpha-1,3-linked water-insoluble glucan and a homologous GTF that synthesizes an alpha-1,6-linked water-soluble glucan. For each enzyme, an 8-mer and 22-mer peptide were prepared. The two peptide lengths were chosen in order to increase the likelihood of the peptides folding in a conformation similar to that of the native enzyme. Each peptide immunogen produced high titers of antibody in rabbits, and all antisera cross-reacted with all peptides, albeit to various degrees. Native enzyme showed weak interaction with antisera, which, on the basis of enzyme denaturation experiments, likely reflects binding to a small but finite population of denatured enzyme in the sample. GTF was assayed for inhibition in the presence of protein A-purified immunoglobulin G from each antiserum. Given the mass of the antibody and catalytic importance of the peptide, any enzyme-antibody complex formation would result in enzyme inhibition. No significant inhibition was observed, which demonstrates that either polyclonal antibodies raised against each of the four peptides cannot access this active-site region, or antibodies do not recognize the native enzyme conformation. The advantages and challenges of generating antibodies against enzyme active-site peptides are discussed in the context of the crystal structure of Aspergillus oryzae alpha-amylase, which has a homologous peptide segment which serves the same catalytic function.

The colour centre in the cerebral cortex of man.

Anatomical and physiological studies have shown that there is an area specialized for the processing of colour (area V4) in the prestriate cortex of macaque monkey brain. Earlier this century, suggestive clinical evidence for a colour centre in the brain of man was dismissed because of the association of other visual defects with the defects in colour vision. However, since the demonstration of functional specialization in the macaque cortex, the question of a colour centre in man has been reinvestigated, based on patients with similar lesions in the visual cortex. In order to study the colour centre in normal human subjects, we used the technique of positron emission tomography (PET), which measures increases in blood flow resulting from increased activity in the cerebral cortex. A comparison of the results of PET scans of subjects viewing multi-coloured and black-and-white displays has identified a region of normal human cerebral cortex specialized for colour vision.