The sense of smell, its signalling pathways, and the dichotomy of cilia and microvilli in olfactory sensory cells

Smell is often regarded as an ancillary perception in primates, who seem so dominated by their sense of vision. In this paper, we will portray some aspects of the significance of olfaction to human life and speculate on what evolutionary factors contribute to keeping it alive. We then outline the functional architecture of olfactory sensory neurons and their signal transduction pathways, which are the primary detectors that render olfactory perception possible. Throughout the phylogenetic tree, olfactory neurons, at their apical tip, are either decorated with cilia or with microvilli. The significance of this dichotomy is unknown. It is generally assumed that mammalian olfactory neurons are of the ciliary type only. The existance of so-called olfactory microvillar cells in mammals, however, is well documented, but their nature remains unclear and their function orphaned. This paper discusses the possibility, that in the main olfactory epithelium of mammals ciliated and microvillar sensory cells exist concurrently. We review evidence related to this hypothesis and ask, what function olfactory microvillar cells might have and what signalling mechanisms they use

Synthetic versus plaster of Paris casts in the treatment of fractures of the forearm in children: a randomised trial of clinical outcomes and patient satisfaction

Fractures of the forearm (radius or ulna or both) in children have traditionally been immobilised in plaster of Paris (POP) but synthetic cast materials are becoming more popular. There have been no randomised studies comparing the efficacy of these two materials. The aim of this study was to investigate which cast material is superior for the management of these fractures. We undertook a single-centre prospective randomised trial involving 199 patients with acute fractures of the forearm requiring general anaesthesia for reduction. Patients were randomised by sealed envelope into either a POP or synthetic group and then underwent routine closed reduction and immobilisation in a cast. The patients were reviewed at one and six weeks. A satisfaction questionnaire was completed following the removal of the cast. All clinical complications were recorded and the cast indices were calculated. There was an increase in complications in the POP group. These complications included soft areas of POP requiring revision and loss of reduction with some requiring re-manipulation. There was an increased mean padding index in the fractures that lost reduction. Synthetic casts were preferred by the patients. This study indicates that the clinical outcomes and patient satisfaction are superior using synthetic casts with no reduction in safety.M. Inglis, B. McClelland, L. M. Sutherland, P. J. Cund

Predicting redisplacement after manipulation of paediatric distal radius fractures: the importance of cast moulding.

INTRODUCTION The majority of displaced distal radius fractures are managed by closed reduction and cast immobilisation. Redisplacement is associated with initial displacement, imperfect reduction and quality of cast. The aim of this study was to establish which factors predict the risk of redisplacement. MATERIALS AND METHODS A retrospective analysis between September 2010 and April 2013 of children who underwent closed manipulation and cast immobilisation for a distal third radius fracture was performed. Open fractures, those treated with fixation, and cases with associated dislocations or physeal injuries were excluded. Initial fracture translation and angulation, the distance from the physis and the presence of an ulna fracture were recorded. Intra-operative radiographs were analysed to assess reduction, the cast index and gap index. Clinic records and post-operative radiographs were reviewed to identify redisplacement or further surgical intervention. RESULTS During the study period, 107 children underwent closed reduction and casting: 82 boys (76.6 %) and 25 girls (23.4 %), and the mean age of the group was 10 years. Twenty-nine children (27 %) suffered a radiographic redisplacement although only five children underwent a second surgical intervention. Statistically significant risk factors for redisplacement were initial fracture translation (p < 0.001), success of reduction (p < 0.001) and associated ulna fracture (p = 0.021). Both the mean cast index (0.81 vs. 0.78) and mean gap index (0.16 vs. 0.14) were higher in the redisplaced group, but this did not reach statistical significance. CONCLUSION Closed reduction and immobilisation of paediatric distal radius fractures is associated with a high redisplacement rate. Initial fracture type and success of reduction are key risk factors