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Biomedical subjects

A Wilkinson

Publications and source records attributed to A Wilkinson.

122 records · Page 7Linked to original sources
PubMed1973

The interaction between ribonuclease A and surfactants.

1. U.v. difference spectra show that the anionic surfactant sodium n-dodecyl sulphate unfolds ribonuclease A at pH7.3 and 10.3, but that the cationic surfactant n-dodecyltrimethylammonium bromide does not affect the conformation of the enzyme. 2. Equilibrium-dialysis experiments show that sodium n-dodecyl sulphate binds to ribonuclease A, but no binding of n-dodecyltrimethylammonium bromide could be detected at pH7.3. 3. The enzymic activity of ribonuclease A is unaffected by n-dodecyltrimethylammonium bromide up to a concentration of 0.03m at 25 degrees C. 4. Ultracentrifuge studies support the conclusion that n-dodecyltrimethylammonium bromide does not interact significantly with ribonuclease A. 5. The enthalpy change as measured by microcalorimetry on binding of sodium n-dodecyl sulphate to ribonuclease A is consistent with an exothermic enthalpy of binding occurring simultaneously with an endothermic enthalpy of chain unfolding.

Calorimetry↗
PubMedDate not supplied

Primary isolation of the bovine spongiform encephalopathy agent in mice: agent definition based on a review of 150 transmissions.

In the epizootic of bovine spongiform encephalopathy (BSE) in Great Britain, the cattle in which a positive diagnosis was made numbered almost 180 000, but strain characterization was performed on only a very small sample of these cases. This report describes the results of BSE transmission to Prnp(a) mice from 150 transmission experiments at the Veterinary Laboratories Agency (VLA) over the last decade. These data, derived from a large sample of BSE-affected cattle, confirmed previous reports that show no evidence for diversity in BSE isolates. The agent was readily transmitted to mice, with a mean incubation period of 408 days in the RIII strain. Because the incubation period was related to the titre of the inoculum, it is not a reliable characteristic of strain type on primary isolation. Consistent neuropathological changes associated with infection by the BSE agent in RIII and C57Bl mice included focal vacuolation in the dorsal cochlear nuclei, vacuolation of the granule cell layer of the cerebellum, absence of lesions in the hippocampus and in the molecular layer of the cerebellum, and a fine particulate distribution of disease-specific PrP (demonstrated immunohistochemically), with few or no amyloid plaques. These features, together with the conventional lesion profile, will be of use in distinguishing the agents of BSE and scrapie in sheep.

Animals↗
PubMedDate not supplied

Transplantation of the canine distal ulna as a free vascularized bone graft.

An autogenous free vascular bone graft of the canine distal ulna was evaluated. The vascularity of the graft was based on a musculoperiosteal sheath supplied solely by the caudal interosseous artery and vein. Four autogenous heterotopic (ulna to tibia) vascular transfers were performed. Two avascular transfers were performed to provide baseline criteria from which the success of vascularized transfers could be assessed. Clinical lameness evaluation, serial radiographs, bone scintigraphy, and sequential fluorochrome bone labeling were performed after surgery in both vascular and avascular transfers. All dogs were free of lameness in the donor limb by the 26th postoperative day. Serial radiographs revealed rapid graft incorporation and hypertrophy in all vascularized grafts and severe bone resorption in nonvascularized grafts. Histology, microangiography, and evaluation of fluorochrome bone labels were performed 90 days after surgery to determine graft viability, incorporation and temporal remodeling patterns. Microangiography and fluorochrome assessment complemented the histological findings. Based on these findings the distal ulnar bone graft was determined to be both viable and structurally adequate for selected cases of long bone reconstruction.

Angiography↗
PubMedDate not supplied

A randomized controlled trial of the effectiveness of exercise and/or alternating air mattress in the control of back pain after percutaneous transluminal coronary angioplasty.

OBJECTIVE: To determine whether an alternating air mattress, a specifically designed exercise program, or both were effective in alleviating back pain in patients after percutaneous transluminal coronary angioplasty (PTCA). DESIGN: 2 by 2 factorial, randomized control trial. SETTING: Intermediate cardiac care unit in a Canadian regional cardiac referral center. SUBJECTS: The sample included 100 subjects, X age 57.4 years, undergoing PTCA. INSTRUMENTS: 10 cm visual analog and Borg scales, both of which measured subjects' perception of pain. RESULTS: The combination of exercise and alternating air mattress is most effective in pain reduction (p = 0.012). CONCLUSION: The combination of exercise and alternating air mattress is more effective in alleviating back pain in patients after PTCA than conventional methods or exercise and alternating air mattress alone.

Adult↗
PubMedDate not supplied

Locally applied transdermal nitrate patches for the treatment of ischaemic rest pain.

Patients with severe peripheral vascular disease may suffer considerable pain which can be difficult to control with conventional analgesics. We sought to assess the analgesic effect of transdermal nitrate patches in such patients. A prospective trial was performed in 15 patients with ischaemic rest pain due to atherosclerotic peripheral vascular disease. Pain control and oral analgesic requirement were assessed. Fourteen of the 15 had a good or moderate response to the nitrate patches with a subsequent reduction in oral analgesic requirement. The patients with primarily small vessel disease had the greatest improvement in pain control. We conclude that topical nitrates may be used to provide rapid and safe analgesia for patients with ischaemic rest pain.

Administration, Cutaneous↗