Model construction by students within an integrated medical curriculum.

BACKGROUND: This paper presents our experience of running a special study module (SSM) in the second semester of the first year of our 5-year medical programme, worth 10 per cent of that semester's assessment, in which each student constructs an individually selected model illustrating a specific aspect of the teaching course. METHOD: Each student conceptualises and develops his or her model, to clarify a specific aspect of medical teaching. The use of non-traditional materials in construction is strongly encouraged. Six weeks later, each student presents their model for assessment by four first-year academic teaching staff. The student is quizzed about the concepts that he or she presents, the mode of construction and the materials used. RESULTS: The students' projects broadly cover the disciplines of physiology, biochemistry and anatomy, but are somewhat biased towards anatomy. Students spend on average about 14 hours planning and building their models, at a time when they are busy with other teaching activities. The marks awarded for the projects closely follow a normal distribution. A survey suggests that most students enjoy the exercise and feel that it has enhanced their learning and understanding. DISCUSSION: It is clear from the wide variety of different topics, models and materials that students are highly resourceful in their modelling. Creative activity does not generally play a substantial part in medical education, but is of considerable importance. The development of their models stimulates, informs and educates the constructors, and provides a teaching resource for later use in didactic teaching.

The distribution of the growth factors FGF-2 and VEGF, and their receptors, in growing red deer antler.

The cellular distributions of the growth factors FGF-2 and VEGF, and their receptors FGFR1, FGFR2 and FGFR3, and VEGFR-2 respectively, were visualized by immunohistochemistry and light microscopy in sections of growing red deer antler. Both of these signalling systems were widely expressed in the integument and osteocartilaginous compartments. FGF-2 was found in the same cells as all three FGFRs, indicating that FGF signalling may be principally autocrine. The patterns of labelling for VEGF and its receptor were similar to those seen for FGF-2 and FGFR-3, in both compartments. Our data are consistent with the findings of others in suggesting that FGF-2 induces expression of VEGF, to stimulate and maintain high rates of neovascularisation and angiogenesis, thereby providing nutrients to both velvet and bone as they rapidly grow and develop. The presence of FGF and VEGF and their receptors in epithelial cells suggests that these signalling systems play a role in skin development, raising the possibility that one or both may be involved in the close coupling of the coordinated growth of the integument and osteocartilage of antler, a process which is poorly understood at present.

Distribution of EGF and its receptor in growing red deer antler.

Autografts of the osteogenic part of early antler buds placed elsewhere on the skull have been shown by others to give rise to an antler at the site of grafting. This antler becomes covered in velvet skin, is shed at the end of the growing season and will regrow the following year. Thus, it can be concluded that the nature of antler velvet skin is primarily determined by the underlying osteogenic antler tissue to which it is attached. We hypothesise that a paracrine mechanism operates here and is central to communication between the antler osseous compartment and the integument. A signalling system comprising epidermal growth factor (EGF) and its receptor (EGFR) is known to be expressed in osteogenic cells and to play an important role in skin development and growth. This system may therefore play a significant role in determining the nature and speed of growth of velvet skin via paracrine signalling from osteogenic tissue. We have used bright-field microscope immunohistochemistry to determine the distribution of EGF and its receptor in developing red deer antler osseous compartment and integument. EGF was localized throughout the epidermis and epidermal appendages, in cells of the mesenchyme, in chondrocytes, and in cells of the osteoblastic lineage, including osteoprogenitor cells, osteoblasts and osteocytes. There was strong evidence supporting nuclear and nucleolar staining in sebaceous glands and in keratinocytes. The EGFR was similarly expressed in mesenchyme, chondrocytes and osteoblasts. In skin, the distribution of the EGFR was more localized, being expressed strongly in the deeper cells of the epidermis but not in superficial layers, and was absent from nuclei of cells of the epidermis and its appendages. We conclude that this signalling system is widely distributed in growing antler in a manner which suggests it is predominantly autocrine. No clear-cut evidence for paracrine signalling pathways for this system in either integument or osseous compartments was found. The pattern of distribution of the EGFR in the integument was similar to that seen by others in adult human skin. By contrast, in developing antler osseocartilage, the patterns of distribution were similar to those seen in rodent fetal bone. We conclude that antler consists of rapidly growing fetal osseocartilage overlayed by mature velvet.