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Biomedical subjects

R M Wilson

Publications and source records attributed to R M Wilson.

95 records · Page 6Linked to original sources
PubMedDate not supplied

Autonomic denervation may be a prerequisite of diabetic neuropathic foot ulceration.

Studies using visceral (cardiovascular) autonomic function testing have left doubt as to the importance of autonomic neuropathy in the development of diabetic neuropathic foot ulceration. A test for peripheral autonomic denervation has been developed (acetylcholine sweatspot test), dependent on intradermal acetylcholine causing secretion by innervated sweat glands, detected by starch/iodine discoloration. The response is photographed and quantified using a grid (normal score = 0 or 1; abnormal = 5 to 60). The sweatspot test was applied to the feet of 19 diabetic patients with a history of foot ulceration, 17 with neuropathic pain, 8 complaining of numbness, and to 15 diabetic control patients. The sweatspot test score of the foot ulcer patients (median 54) was very much greater than that of the other groups (pain group, 4, p less than 0.005; numbness group, 2, p less than 0.01; diabetic control group, 2, p less than 0.0001). All the patients with neuropathic foot ulceration had peripheral autonomic denervation. The results suggest that autonomic denervation in the feet is always present in patients with diabetic neuropathic foot ulceration. Tests of peripheral autonomic denervation such as the acetylcholine sweatspot test may be useful to identify patients at risk of neuropathic foot ulceration.

Acetylcholine↗
PubMedDate not supplied

Synchrotron x-ray microtomographic investigation of mineral concentrations at micrometre scale in sound and carious enamel.

Synchrotron X-ray microtomography (XMT) was used to measure the linear attenuation coefficient (LAC) for 1.9-microm sidelength voxels within approximal brown spot lesions and sound human enamel. XMT demonstrated three-dimensional features, notably sheets with approximately 30 microm periodicity having low LAC, identified as regions of demineralization corresponding to Retzius lines. Quantitative three-dimensional measurements of mineral concentration, derived from LAC with assumption of a single model composition, were consistent with previous measurements of sound and carious enamel from microradiographic projections. The uncertainty in measurements of mineral concentration and mineral fraction volume was investigated by modelling enamel with a range of composition and component densities. This analysis showed that, although mineral concentration can be determined from LAC with an error of <0.2 g cm(-3), the variation in pore fraction volume within caries lesions cannot be reliably determined from X-ray attenuation measurements alone.

Apatites↗
PubMedDate not supplied

Demineralization around orthodontic brackets bonded with resin-modified glass ionomer cement and fluoride-releasing resin composite.

PURPOSE: Enamel demineralization adjacent to orthodontic brackets is one of the risks associated with orthodontic treatment. Glass ionomer cements have been shown to decrease enamel demineralization adjacent to brackets and bands but do not exhibit bond strengths comparable to resin composites. The purpose of this in vitro study was to compare a fluoride-releasing resin composite versus a resin-modified glass ionomer cement for inhibition of enamel demineralization surrounding orthodontic brackets. METHODS: Forty-five teeth were randomly assigned to 3 groups of 15 teeth. Fifteen were bonded with Concise (3M), a non-fluoride-releasing resin composite (control); 15 teeth were bonded with Light Bond (Reliance), a fluoride-releasing resin composite; and 15 teeth were bonded with Fuji Ortho LC (GC Corporation), a resin-modified glass ionomer cement. The teeth were placed in an artificial caries solution to create lesions. Following sectioning of the teeth in a buccolingual direction, polarized light microscopy was utilized to evaluate enamel demineralization adjacent to the orthodontic bracket. The area of the lesion was measured 100 microns from the orthodontic bracket and bonding agent. RESULTS: MANOVA (P < .0001) and Duncan's test (P < .05) indicated the resin-modified glass ionomer cement (Fuji Ortho LC) and the fluoride-releasing resin composite (Light Bond) had significantly less adjacent enamel demineralization than the non-fluoride-releasing resin composite control. However, there was no significant difference between the resin-modified glass ionomer cement and the fluoride-releasing resin composite. CONCLUSIONS: Based on the results of this in vitro study, it can be concluded that Fuji Ortho LC and Light Bond exhibit significant inhibition of adjacent demineralization compared to the non-fluoride-releasing control.

Acrylic Resins↗