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Biomedical subjects

F A Billson

Publications and source records attributed to F A Billson.

At least 55 records · Page 3Linked to original sources
PubMed1992

Nonabsorbable suture material in cataract surgery: a comparison of Novafil and nylon.

We compared the performance of 10-0 Novafil (polybutester, Davis & Geck, American Cyanamid Company, New South Wales, Australia.) with that of 10-0 nylon (Alcon) in 60 patients undergoing extracapsular cataract extraction and implantation of a posterior chamber intraocular lens. A standard technique was used, and the incision was closed with interrupted sutures of either 10-0 Novafil or 10-0 nylon. Length of follow up ranged from 6 to 26 months (average, 15 months). We assessed the intraoperative handling qualities of the suture materials, as well as their effect on wound healing and inflammation. We also compared the surgically-induced astigmatism in the two suture groups over the first 3 postoperative months and then in long-term follow up (average, 15 months). Sutures removed at long-term follow up were examined by scanning electron microscopy (SEM). Both suture materials handled easily at operation and were well tolerated by all patients. There was no significantly different surgically-induced astigmatism in the two suture groups after 12 weeks (P = .962) or during longer follow up (P = .401). SEM confirmed more advanced biodegradation of nylon as compared with Novafil sutures after they had been in place an average of 18 months.

Adult↗
PubMed1991

Problems in the diagnosis and management of unilateral retinoblastoma.

The improved prognosis for life in retinoblastoma challenges us to readdress the severe morbidity associated with late presentation and treatment, particularly in unilateral disease. Three cases of unilateral sporadic retinoblastoma are presented to illustrate the range of therapeutic options that need to be considered in management and to show that early recognition of the tumour and local treatment have the potential to minimise morbidity and to enable binocular vision to be retained.

Antineoplastic Agents↗
PubMed1991

A case of progressive hemifacial atrophy with uveitis and retinal vasculitis.

Parry Romberg syndrome is a rare disorder characterised by progressive hemifacial atrophy that is usually unilateral, involving the skin, subcutaneous tissue, and subsequently the muscle, cartilage and bone. Previous cases with various ocular manifestations have been reported. A case of Parry Romberg syndrome with retinal vasculitis is reported.

Alopecia↗
PubMed1991

Visual disability and major causes of blindness in NSW: a study of people aged 50 and over attending the Royal Blind Society 1984 to 1989.

Visual disability in individuals aged 50 years and over seeking services of the Royal Blind Society in the years 1984 to 1989, was studied with respect to changes in frequency of major causes together with age and sex of those affected. The results mirror statistics in the UK. Age-related macular degeneration (AMD) accounts for an increasing proportion of visual disability (34% in 1984 to 43% in 1989). Of particular interest was the frequency of disability attributed to cataract. While decreasing (24% in 1984 to 19% in 1989), cataract still represents a significant cause of potentially treatable disability. The authors conclude that there is a changing prevalence of visual disability caused mainly by an increase in AMD and a subgroup of patients attending for services who appear to have a potentially remediable disability. These conclusions affirm the need for close liaison between ophthalmological practitioners and agencies for the blind.

Aged↗
PubMed1991

Long-term comparison of Novafil and nylon in corneoscleral sections.

To compare the long-term degradation of Novafil (polybutester, American Cyanamid Company) and nylon suture material, we examined corneoscleral sections of nine rabbits 23 months after the placement of sutures. Only two nylon sutures remained, one in each wound of two rabbits; all the Novafil sutures were still present. However, examination of the Novafil sutures with scanning electron microscopy revealed signs of disintegration.

Animals↗
PubMed1990

Early differentiation of ganglion, amacrine, bipolar, and Muller cells in the developing fovea of human retina.

We examined the differentiation and maturation of neurons and glia of the inner nuclear layer (INL) and ganglion cell layer (GCL) in the retina of a human fetus of 15 weeks gestation. Serial, ultrathin sections were cut from a resin-embedded specimen from the posterior pole of the retina. The region of the putative fovea was defined by the absence of rod photoreceptors from the outer nuclear layer; only sections through the putative fovea were studied. Cell somata were classified on the basis of morphological criteria and, through the analysis of serial sections, morphological characteristics of the cell processes were established. In the inner plexiform layer (IPL), the types of synapses were analysed. The majority of cells in the INL and GCL were differentiated and could be identified. Ganglion cell somata were observed in the GCL and INL. Of 186 somata analysed in the INL, 66 were Muller cells, 21 amacrine cells, and 2 ganglion cells; a further 7 cells were classified as either amacrine or ganglion. Bipolar cells were thought to comprise the majority of the remaining 90 somata, but these could not be positively identified, as it was not possible to trace bipolar cell axons to their cell bodies deep in the INL. A detailed description of the morphological characteristics of the identified cells and their processes, and of the axonal processes of bipolar cells, is provided. Puncta adherentia and other simple intercellular junctions were commonly seen in the IPL and involved all cell types. Amacrine cell synapses and immature, monad bipolar cell synapses were common within the IPL. Dyad bipolar synapses were uncommon at this stage of development. A possible sequence of synaptogenesis in the IPL is discussed.

Cell Differentiation↗
PubMed1990

Angiogenesis in normal human retinal development: the involvement of astrocytes and macrophages.

Recent studies have suggested a role for mononuclear phagocytes series (MPS) cells in neovascularisation associated with retinal pathology and experimentally induced subretinal neovascularisation. The present study is concerned with the normal development of the human retinal vasculature. Morphological details are provided of developing vascular structures including the formation of tight junctions and canalisation of angioblast cords. The relationships of astrocytes and pericytes to developing structures and the presence of a perivascular collagenous matrix are described. Ultrastructural and histochemical analyses reveal an association between MPS cells and developing vascular structures. It is suggested that MPS cells may influence angiogenesis in normal retinal development, as well as in retinal pathology.

Astrocytes↗
PubMed1990

Autoantibodies to retinal astrocytes associated with age-related macular degeneration.

Sera from 128 patients with age-related macular degeneration (AMD) were examined and profiles of a variety of serum constituents, including immunoglobulins, alpha and beta globulins and autoantibodies, were tabulated. A similar series of tests were carried out on 20 control sera. The results indicate a higher incidence of serum abnormalities, particularly involving alpha-2 globulin, in patients with disturbance of pigmentation of the retinal pigment epithelium (RPE). The sera were further tested for the presence of autoantibodies with specificity for retinal tissue, and five major staining patterns were observed. Many sera produced patterns of labelling on human retina identical to that observed using labelled monoclonal anti-glial fibrillary acid protein (GFAP) antibodies, which are an established marker of retinal astrocytes. Although anti-retinal autoantibodies have been reported in association with a number of ocular pathologies, the observation of anti-astrocyte autoantibodies is new. Astrocytes are involved in the maintenance of the blood-retinal barrier (BRB) and also appear to be the facultative antigen-presenting cells of neural tissue. The present results indicate that the formation of anti-astrocyte autoantibodies may be an early feature of the pathogenesis of AMD.

Aged↗
PubMed1990

A thin I-125 seed eye plaque to treat intraocular tumors using an acrylic insert to precisely position the sources.

A thin re-usable stainless steel ophthalmic applicator is described. The radioactive Iodine-125 sources are inserted in an acrylic button which fits neatly into a stainless steel shell 1 mm thick. The applicator can be assembled with the radioactive sources precisely positioned without the use of adhesives or mechanical devices such as clamps or screws in a matter of a few minutes, (under sterile conditions if necessary). The applicator can be dismantled in seconds after which it is ready for cleaning and re-sterilization. The overall thickness of the plaque is 2.6 mm, but this has the potential to be reduced to 2.1 mm. Suture holes are provided on a flange subtending 120 degrees around the circumference of the shell and are exactly matched on a stainless steel template.

Acrylates↗
PubMed1990

The conservative management of choroidal melanoma.

The results of 32 choroidal melanomas managed by observation, Iodine-125 scleral plaques and local surgical excision are presented. Initially, 12 patients were managed by observation, and of these three continued to be managed by observation alone. Fifteen patients were managed with Iodine-125 scleral plaques and followed for an average of 15 months. The tumour regressed in 11, remained the same in three, and recurred in one case. The final visual acuity remained within two Snellen lines of that recorded preoperatively in 10 patients. Fourteen patients underwent local excision with an average follow-up of 31 months. These cases, in general, had larger tumours. The final visual acuity was within two Snellen lines of the preoperative vision in four patients. Five eyes required enucleation at a later date. Four of the five enucleations occurred earlier in the series. The management of choroidal melanoma remains controversial. Various methods of conservative treatment are described and the indications for conservative management by observation, scleral plaque and local excision are discussed.

Adult↗
PubMed1990

Ultrastructural features of contact lens-induced deep corneal neovascularization and associated stromal leukocytes.

Deep stromal vascularization was observed in corneas of four cynomolgus monkeys after extended monocular hydrogel contact lens wear. Keratocytes and extravascular leukocytes, including macrophages, lymphocytes, and in one case, neutrophils, were associated with the vessels in three monkeys. Vessel regression was observed in some animals, but not when lens wear was continuous. In one animal, neutrophil infiltration of the stroma associated with gross epithelial edema was observed. Involution of neutrophils by apoptosis and phagocytosis of pyknotic cells by macrophages was noted. The present study describes the ultrastructural features of deep corneal vascularization developed during extended contact lens wear and illustrates an association between leukocytes and new vessels.

Animals↗
PubMed1989

The wide-angle pattern electroretinogram. Relation between pattern electroretinogram amplitude and stimulus area using large stimuli.

Pattern electroretinograms (PERGs) were recorded from two normal human subjects in response to various spatial frequencies and stimulus areas. The maximum stimulus area was 75 degrees x 86 degrees which was achieved by using a standard TV monitor and a reduced viewing distance. The amplitude of the PERG increased with area in an approximately logarithmic fashion over the range investigated. The explanation relates to non-linearities of the stimulus, the retinal image and neural processing. The wide-angle PERG may be useful in the assessment of retinal diseases affecting the mid-peripheral inner retina, such as diabetic retinopathy.

Electroretinography↗
PubMed1989

Malignant melanoma associated with human immunodeficiency virus infection in three homosexual men.

This report concerns three patients with human immunodeficiency virus (HIV) infection in whom malignant melanoma developed. One patient had metastatic malignant melanoma, one had iris melanoma, and one had a single skin melanoma. All three had lower absolute numbers of CD4+ cells than a control group, and the severity of their disease was inversely proportional to the absolute number of CD4+ cells. This report suggests an association between the immunodeficiency resulting from HIV infection and the development of malignant melanoma.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Supranuclear disorders of eye movement.

Eye movements are the result of activity in discrete systems. Saccades and smooth pursuit movements respond to target position and target velocity respectively. Compensatory responses to movements that alter the position of the eyes in space depend upon the vestibular and optokinetic systems. Vergence movements allow fusion and binocular vision. Eye movement abnormalities of supranuclear origin may be divided into nystagmus, other ocular oscillations, saccadic dysfunction, smooth pursuit dysfunction, gaze palsy, tonic deviation, and vergence disability. An algorithm for the analysis of supranuclear eye movement disorders is presented.

Convergence, Ocular↗
PubMed1989

Postural drainage in the management of postoperative hyphaema.

We describe the technique of postural drainage of hyphaemas following trabeculectomy alone or when combined with lens extraction and intraocular lens implantation. This technique helps avoid surgical intervention and seems to have no short-term deleterious effect on bleb function.

Cataract Extraction↗
PubMed1989

Atypical mycobacterial keratitis.

A case of marginal corneal abscess and hypopyon due to Mycobacterium chelonae is presented. Its therapy is described, followed by a brief discussion of atypical mycobacterial keratitis.

Abscess↗