Biomedical subjects

A W MacDonald

Publications and source records attributed to A W MacDonald.

21 records · Page 2Linked to original sources

PubMed1989

Expression of cytokeratin in the epithelium of dentigerous cysts and odontogenic keratocysts: an aid to diagnosis.

Sections of tissue embedded in paraffin wax from 18 selected odontogenic cysts were studied both histologically and immunohistochemically with antibodies to cytokeratins using the indirect peroxidase technique. The cysts were divided on a clinical and histological basis into two equal groups comprising dentigerous cysts and odontogenic keratocysts. It was possible to differentiate the two cyst types in every case by the pattern of staining using the monoclonal antibody LP34 for cytokeratins of intermediate molecular weight. The monoclonal antibody CAM 5.2 for cytokeratins of low molecular weight was not discriminatory. Such a clear distinction may prove useful diagnostically in distinguishing between two cysts of similar appearance but very different behaviour.

Dentigerous Cyst↗

PubMedDate not supplied

Giant colonic diverticulum.

BACKGROUND: Over 100 giant colonic diverticuli have been recorded in the literature to date. The magnetic resonance imaging (MRI) and pathophysiology of their aetiology have rarely been described. AIM: To report a giant colonic diverticulum along with the MRI of this clinical entity. RESULTS: An 87 year old female presented with symptoms of tenesmus, urgency and alteration in bowel habit. A type I giant colonic diverticulum was diagnosed and a segmental colonic surgical resection was performed. The plain abdominal radiograph, barium enema and MRI, along with classification and management options are presented. CONCLUSION: Giant colonic diverticuli are rare surgical curiosities that may be successfully treated with either primary segmental or extended colonic resection.

Aged↗

PubMedDate not supplied

Directional atherectomy in iliac stent failure: clinical technique and histopathologic correlation.

PURPOSE: To assess the feasibility and efficacy of directional atherectomy in the treatment of iliac stent stenosis or occlusion and to evaluate the histologic composition of excised atherectomy specimens. METHODS: Directional atherectomy of six occluded and 10 severely stenosed iliac stents was undertaken in 12 patients at a mean interval of 28 months (range 3-69 months) after stent insertion for occlusive aortoiliac disease. In cases of stent occlusion, atherectomy was preceded by low-dose thrombolysis. In all patients stent clearance with return of femoral pulses was achieved within 24 hr and there were no significant complications. All excised specimens were sent for histologic examination. RESULTS: Eleven patients (92%) remain symptom free with unlimited walking distance at a mean follow-up interval of 11.5 months (range 3-31 months) after treatment. Histologic examination revealed typical myointimal hyperplasia at three excision sites, intimal fibrosis at three sites, atheroma at four sites and organized thrombus at six sites. CONCLUSION: Atherectomy offers an effective treatment in iliac stent occlusion and restenosis with no significant adverse effects. Debulking of these lesions seems to offer a more logical approach than simple balloon angioplasty. Clinical and duplex follow-up confirms satisfactory outcome within the first year but longer-term results are not yet known. The histologic data obtained demonstrate that stent restenosis and occlusion are likely to be multifactorial, and challenge the assumption that myointimal hyperplasia is the sole cause of iliac stent occlusion.

Aged↗