Search PubMed⌕ Search

Biomedical subjects

D McLeod

Publications and source records attributed to D McLeod.

At least 163 records · Page 9Linked to original sources
PubMed1989

Abortive neovascular outgrowths discovered during vitrectomy for diabetic vitreous haemorrhage.

Abortive neovascular outgrowths from the retina were identified in 13 out of 34 eyes (38%) undergoing vitrectomy for diabetic vitreous haemorrhage. Postoperatively, fluorescein angiography of the lesions demonstrated a characteristic "smoke-stack" pattern of dye leakage. Each outgrowth appears to represent a focal variant of preretinal neovascularisation complicating retinal capillary non-perfusion and inner retinal ischaemia, their distinctive features being determined primarily by the absence of a cortical vitreous scaffold on the retinal surface at the time of vasoproliferation.

Cross-Sectional Studies↗
PubMed1989

Retinal patching: a new approach to the management of selected retinal breaks.

Restoration of retinal continuity by a patching technique is proposed as a new means of treating selected rhegmatogenous retinal detachments where established techniques frequently fail. The patch consists of a substrate and adhesive applied to the inner surface of the retina surrounding the retinal break. Bovine eye cup experiments have been performed to explore the effectiveness of a range of adhesives, and cyanoacrylates and Tisseel have been found to be effective. Studies of these adhesives on confluent cultures of bovine retinal pigment epithelial cells and glia revealed temporary cyanoacrylate toxicity and stimulation of proliferation by Tisseel. Substrate biocompatability was investigated by observing the growth of cells on various substrates in tissue culture; biological substrates such as lens capsule supported cell growth whereas synthetic membranes only did so if pretreated with fibronectin.

Animals↗
PubMed1989

Indentation microsurgery: internal searching for retinal breaks.

Breaks responsible for rhegmatogenous retinal detachments in 78 eyes could not be seen preoperatively owing to opacities in the media, previous buckling or other causes. Deep kinetic indentation of the sclera combined with endoillumination enabled retinal breaks to be identified during closed microsurgery in 95% of these eyes, and retinal reattachment was eventually achieved in 85%.

Adolescent↗
PubMed1989

Endothelial cell-stimulating angiogenesis factor in vitreous from extraretinal neovascularizations.

The presence of endothelial cell-stimulating angiogenic factor (ESAF) in diseased human vitreous humour has been established. The molecular mass and chromatographic behavior of this material and its property of activating procollagenase indicate it to be identical to the ESAF isolated from other sources. The biological activity of ESAF from human vitreous was demonstrated by its ability to induce positive responses in the rabbit corneal pocket, and in the chick chorioallantoic membrane and yolk sac membrane tests.

Angiogenesis Inducing Agents↗
PubMed1988

Retinal pigment epithelial cells in culture produce retinal vascular mitogens.

Conditioned medium from human retinal pigment epithelial cells in culture significantly stimulated the proliferation of subcultured bovine retinal capillary endothelial cells, pericytes, and freshly isolated retinal microvessels. The vascular mitogenic activity enhanced that of retinal crude extract. No evidence emerged of an inhibitor of microvascular cellular proliferation produced by retinal pigment epithelial cells.

Animals↗
PubMed1988

Inflammation and the formation of epiretinal membranes.

In this review of the literature evidence is provided from clinical, histological and experimental sources that inflammatory processes play a central role in the pathogenesis of contractile epiretinal membranes and proliferative vitreoretinopathy.

Animals↗
PubMed1988

Growth and contractility of cells from fibrocellular epiretinal membranes in primary tissue culture.

Cells grew out in tissue culture from 37 of 53 fibrocellular epiretinal membrane explants, those from membranes of less than four months' clinical duration growing more consistently, more rapidly, and more exuberantly than those from membranes of more than four months' clinical duration. Electron microscopy demonstrated prominent microfilaments in the cytoplasm of some of the cells, and immunostaining for actin showed great variations in the pattern and intensity of staining. An ATP contraction assay conducted on 44 detergent-extracted cells and 47 intact cells revealed in each case a 30% average reduction in cell area. Immunostaining for cytokeratins following the ATP assay showed no significant difference in cell contraction between epithelial cells and non-epithelial cells. Clinical duration of the membrane had no significant influence on the contractility of cells growing from the explant.

Actin Cytoskeleton↗
PubMed1988

Viscodelamination at the vitreoretinal juncture in severe diabetic eye disease.

Injection of 1% methylcellulose or 1% sodium hyaluronate (Healonid) was used to separate attached vitreous cortex and fibrovascular epiretinal membranes from the retina in 40 eyes undergoing closed microsurgery for severe diabetic eye disease. The viscodelamination technique was of great value in elevating vitreous cortex or sparsely vascularised epiretinal membranes, especially in eyes with combined traction and rhegmatogenous retinal detachment. However, bleeding from or tearing of the retina limited the usefulness of this technique in the surgery of highly vascularised and adherent membranes, as in eyes with table-top traction retinal detachment. Recurrent epiretinal membrane proliferation was seen in some eyes postoperatively.

Diabetic Retinopathy↗
PubMed1988

The role of inflammation in the development of epiretinal membranes.

Single or multiple (3) injections of "Shigella" endotoxin were administered into the rabbit vitreous body to investigate the development of epiretinal membranes following intraocular inflammation. The evaluation included clinical assessment of the resulting traction retinal detachments, together with histological, autoradiographic, immunohistochemical and ultrastructural studies. Traction retinal detachments were found beneath fibroglial epiretinal membranes (being more extensive in eyes which had received 3 endotoxin injections) in the vicinity of the medullary rays, while purely glial membranes occurred over attached peripheral retina. The primary change at the vitreoretinal interface was an elevation of the inner limiting lamina of the retina followed by the extension of glial cells onto the retinal surface. It is postulated that glial cells breach the inner limiting lamina as a sequel to inflammation involving the vitreoretinal interface and form a scaffold upon which fibroblast-like cells migrate.

Animals↗
PubMed1988

Effects of vitreous from photocoagulated eyes on retinal microvascular cells in culture: a preliminary report.

Panretinal photocoagulation was carried out in mini pigs in an attempt to elucidate the mechanisms involved in laser therapy. The effect of the vitreous from these eyes on the proliferation of retinal microvascular endothelial cells was then studied. Vitreous removed 4 days after panretinal photocoagulation had no effect on the proliferation of bovine retinal microvascular endothelial cells in basal medium but inhibited proliferation in growth medium. Control vitreous was mitogenic for the microvascular cells in basal medium but this effect was not observed in growth medium.

Animals↗
PubMed1987

Pars plana vitrectomy for vitreous amyloidosis.

Thirty-six pars plana vitrectomies were performed on 30 eyes of 17 patients with biopsy-proven vitreous amyloidosis. Reopacification of the retrolental vitreous was the most common reason for vitrectomy revision, required in 24% of patients. Complications of amyloid or vitrectomy included retinal detachment requiring scleral buckling in 17% of eyes and glaucoma requiring filtering surgery in 17% of eyes. After a mean 35-month post-vitrectomy follow-up, 48% of eyes had visual acuities of 20/40 or better, and 32% of eyes had visual acuities between 20/50 and 20/100. Twenty percent of eyes had visual acuities of 20/200 or worse due either to persistent retinal detachment, open angle glaucoma, or residual opacification of the vitreous.

Amyloidosis↗
PubMed1987

Intraocular argon laser photocoagulation.

Intraoperative photocoagulation using an endolaser delivery system is an important recent development in the field of vitreous microsurgery. Endolaser photocoagulation is indicated in a wide variety of vitreoretinal disorders and offers important advantages over previous techniques of endophotocoagulation using xenon energy. We review our experiences of argon laser endophotocoagulation to identify the role of this technique, the potential hazards and stringent precautions required for theatre personnel.

Animals↗
PubMed1987

Closed microsurgery for the sequelae of neovascularisation from veno-occlusive retinopathies.

Our experience of closed microsurgery for vitreous haemorrhage and/or traction retinal detachment complicating extraretinal neovascularisation after retinal vein occlusion or Eales' and Behçet's periphlebitis is discussed. Many of these eyes represented a relatively simple management problem, but the visual outcome was often compromised by intrinsic macular damage. Some eyes had complicated vitreoretinal relationships which presented unexpected technical difficulties, while persisting retinal ischaemia posed the risk of rubeosis iridis or post-operative vitreous haemorrhage unless scatter endophotocoagulation was used.

Cataract Extraction↗
PubMed1987

Age-related cellular proliferation at the vitreoretinal juncture.

Clinical and pathological features of non-vascularised epiretinal membranes are reviewed with special attention to focal epimacular tractional lesions in the elderly. The role of immunohistochemistry in elucidating the nature of component cells of complex epiretinal membranes is emphasised. Clinicopathological correlation establishes the 'fibroglial membrane' as the causative lesion of age-related epimacular traction. The pathogenesis of this process is discussed, including relevant animal models, and chronic inflammation and ischaemia (rather than acute posterior vitreous detachment) are implicated. Vitrectomy and epimacular membrane peeling results in significant visual improvement in most patients.

Adult↗