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Biomedical subjects

B A Noble

Publications and source records attributed to B A Noble.

At least 19 recordsLinked to original sources
PubMed1997

Do transplanted corneal limbal stem cells survive in vivo long-term? Possible techniques to detect donor cell survival by polymerase chain reaction with the amelogenin gene and Y-specific probes.

PURPOSE: To investigate donor cell survival following corneal limbal stem cell grafting, which is based on the corneal stem cell model. METHODS: We describe the use of the amelogenin gene probe with the polymerase chain reaction (PCR) to detect surviving donor cells and report preliminary studies using Y-specific DNA probes. RESULTS AND CONCLUSIONS: DNA polymorphisms have a detection limit of 10%. The SRY 'Y-specific' probe has a theoretical detection limit of 1 cell in 10,000. The techniques were applied to investigate survival of male donor cells in an aniridic female patient 2 1/2 years following limbal stem cell grafts. We speculate that low levels of donor-derived cells may still be present. We discuss the advantages and disadvantages of the two approaches, which may have future clinical and experimental application.

Amelogenin↗
PubMed1996

Early-onset posterior polymorphous dystrophy.

We report an unusual case of posterior polymorphous dystrophy in which corneal failure began within a few weeks of birth. Histopathologic findings included the presence of abnormal corneal endothelial cells with many microvilli on the surface. Descemet membrane was severely attenuated, and there was a thick posterior collagenous layer consisting of numerous fibroblast-like cells in a fibrillar extracellular matrix; ultrastructural immunocytochemistry showed this to contain tenascin, fibronectin, and collagen type I. Few histopathologic data on this disease at such an early age have been available, and to our knowledge, the composition of Descemet membrane has not been examined before. The microvilli-covered cells are shown to be present from the outset of the disease, not just in long-standing cases as in previous reports; changes in Descemet membrane may influence disease evolution.

Age of Onset↗
PubMed1995

Factors affecting visual outcome in children following uniocular traumatic cataract.

The correction of paediatric traumatic aphakia remains a controversial topic. This study examines retrospectively the visual outcome in 32 children with uniocular traumatic cataracts. Fifteen received intraocular lens implants following lensectomy, and 17 received aphakic contact lenses. Age range was 2-14 1/2 years at the time of injury. The maximum follow-up time was 13 years. Twenty-four children obtained a good visual result (6/5 to 6/18). These were equally divided between those receiving intraocular lens implants and those with contact lenses. Factors adversely affecting visual outcome are discussed. These include complex trauma, delay in referral for lensectomy, inadequate postoperative correction of aphakia, contact lens difficulties and problems with occlusion therapy. Although aphakic correction with intraocular lens implants may require several subsequent surgical procedures such as capsulotomy, we advise early lensectomy and intraocular lens implantation where possible, particularly in young children with traumatic cataracts. This eliminates contact-lens-associated problems and maximises the chance of good visual outcome and retention of stereoscopic vision.

Adolescent↗
PubMed1994

Retinal and optic disc neovascularization in leukaemia.

We report a case of chronic myeloid leukaemia initially presenting with a vitreous haemorrhage associated with bilateral retinal and optic disc neovascularization. The literature is briefly reviewed and the probable reasons for the observed microcirculatory disturbances are discussed.

Aged↗
PubMed1994

Aggressive management of an epidemic of chronic pseudophakic endophthalmitis: results and literature survey.

Six cases of chronic endophthalmitis following extracapsular cataract extraction and lens implantation are reviewed. All were referred for tertiary management by one surgeon over a period of just over 2 years. In two of the cases coagulase negative staphylococci were isolated and in three Propionibacterium spp were retrieved. In the remaining case a mixed growth of coagulase negative staphylococci and Propionibacterium acnes was cultured. The surgical management, microbiological results, and eventual visual outcome are discussed. To our knowledge, this is the first documented outbreak of chronic pseudophakic endophthalmitis with commensal organisms from a single centre.

Aged↗
PubMed1994

A comparative study of the elastic properties of continuous tear curvilinear capsulorhexis versus capsulorhexis produced by radiofrequency endodiathermy.

Capsulorhexis using radio-frequency endodiathermy may confer some advantages over continuous tear curvilinear capsulorhexis (CTCC) in certain clinical situations. It is unclear whether a capsulorhexis produced in this fashion has the clinically advantageous elasticity and resistance to tearing that a CTCC has been demonstrated to have. To investigate this, a test of capsular elasticity was carried out on pairs of eyes obtained from an eye bank, 42 eyes of 21 patients in total, using modified digital vernier calipers. One eye of each pair had a CTCC, the other a diathermy capsulorhexis (DC). The elasticity of the capsule in both groups was expressed by comparing the circumference of the capsulotomy at rest with its circumference at rupture. The mean capsular elasticity of the CTCC group was significantly greater than that of the DC group (p << 0.001). The capsular edge in both groups was examined using scanning electron microscopy, and the difference in morphology appears to be the source of the difference in elasticity.

Adolescent↗
PubMed1993

Development of atypical amiodarone keratopathy in a corneal graft.

The presence of fine epithelial deposits in a whorled pattern (cornea verticillata) as a consequence of treatment with amiodarone is well documented. We present a case of amiodarone keratopathy in a grafted cornea which is atypical in that the orientation of the pattern is rotated through nearly 90 degrees to that normally observed. This observation runs counter to the hypothesis that cornea verticillata is a manifestation of the line of lid closure. We speculate on the mechanism directing the migrational pathways of epithelial cells.

Aged↗
PubMed1993

The role of intraocular lens exchange in the management of major implant-related complications.

This study evaluates the role of intraocular lens exchange procedures in the management of major implant-related complications. Medical records of 30 patients undergoing intraocular lens exchange at the Leeds General Infirmary from 1 January 1984 to 30 November 1991 were reviewed. Details of their primary implantation surgery, intervening ophthalmic history, lens exchange surgery and outcome were analysed. Follow-up ranged from 3 to 210 weeks. Seventy-six per cent of cases achieved final visual acuity of 6/12 or better. Visual acuity improved in 60%, worsened in 6.6% and was unchanged in 33.4% compared with pre-operative levels. Three patients had cystoid macular oedema, 3 ocular hypertension, 2 bullous keratopathy, 1 chronic anterior uveitis and 1 patient developed a retinal detachment. This approach to managing major implant-related complications gives good visual results. There is a significant complication rate but the risk-benefit ratio justifies the use of the technique.

Adult↗
PubMed1990

Secondary evaluation of hydrogel lens implants.

OBJECTIVE: To review patients currently forming part of a study of poly 2 hydroxyethylmethacrylate (P-HEMA) 'Hydrogel' intraocular lenses. DESIGN: Patients were taking part in the Hydrogel arm of a prospective trial at Scarborough Hospital. Recruitment was by letter. SETTING: District General Hospital. PATIENTS: One hundred and eight from the Scarborough trial in whom a Hydrogel lens had been implanted. INTERVENTIONS: An independent assessment was carried out at a median interval of 20 months following surgery. Visual acuities were assessed with best possible refraction and the eyes examined both before and after pupil dilation. MAIN OUTCOME MEASURES: Visual acuity and major complications. RESULTS: 91% had visual acuities of 6/9 or better and 30% achieved 6/5. In 61% the central area (3 mm diameter) of posterior capsule was clear but 39% had significant fibrosis or pearl formation in this area and 8% had undergone posterior capsulotomy. Five major decentrations had taken place, one of which occurred following a spontaneous rupture of the posterior capsule 17.6% of patients showed significant pigment dispersion behind the IOL either on the posterior capsule or in the anterior vitreous that could not be accounted for purely by surgical trauma. An atonic iris sphincter was noted in 17% of eyes. CONCLUSIONS: This lens gives good visual results but its stability and tendency to cause pigment shedding need to be closely monitored.

Aged↗
PubMed1990

Secondary intraocular lens implantation: eight year experience.

OBJECTIVE: To investigate the outcome of secondary intra-ocular lens implantation. Neither a requirement for vitreous surgery nor previous complicated eye surgery/trauma was considered necessarily to be a contra-indication. DESIGN: Retrospective Study. Recruitment was achieved by examination of operating theatre records. SETTING: Teaching Hospital. PATIENTS: 52 out of 54 consecutive cases in whom a secondary lens had been implanted from 1982-1989 under the care of one consultant (BAN). INTERVENTIONS: The medical records of all patients were reviewed and data collected for 52 of the total of 54 patients. MAIN OUTCOME MEASURES: Visual acuity and major complications. RESULTS: 77% of eyes retained the same Snellen visual acuity or better than that pre-operatively and 88% were within one line or better. The Mann Whitney U-test showed that neither vitreous manipulation at the time of secondary lens implantation nor a previous history of trauma had a significant effect on the change between pre- and post-operative Snellen visual acuity. Only one patient developed a retinal detachment and eight had cystoid macula oedema although in only one patient did this account for a final decrease in post-operative visual acuity of more than one line. The most common complication was an intense post-operative uveitis (35%) leading in some cases to indefinite low dose topical steroid treatment (21%). CONCLUSIONS: This technique gives good visual results, even in the disorganised eye, providing the vitreous is adequately managed. However there is a significant complication rate which should be discussed with the patient before undertaking surgery.

Adult↗
PubMed1989

Bacterial contamination of intraocular lenses: the source of the bacteria.

In order to investigate potential sources for the bacterial contamination of intraocular lenses, specimens were taken for culture from a variety of sites. A swab from the lid margin, the operating room air, an intraocular lens which was allowed to rest on the eye, and the sodium hyaluronate were cultured during routine intercapsular lens implant surgery on 31 patients. Positive cultures were obtained from six intraocular lenses. Subtyping by three independent methods showed that isolates from five of these lenses were indistinguishable from bacteria cultured from the air. In the case of the sixth lens a bacterial isolate from the lid margin matched with that from the lens. Staphylococcus epidermidis was cultured from four lenses; Staphylococcus haemolyticus was also isolated from one of these four lenses and the remaining two lenses produced isolates of Staphylococcus aureus.

Air Microbiology↗
PubMed1987

Hereditary sensory neuropathy with neurotrophic keratitis. Description of an autosomal recessive disorder with a selective reduction of small myelinated nerve fibres and a discussion of the classification of the hereditary sensory neuropathies.

A Kashmiri family with 3 members affected by a congenital sensory and autonomic neuropathy and corneal opacification is described. The 3 affected cases were offspring of consanguinous marriages in two generations; autosomal recessive inheritance is therefore probable. Pain and temperature sensation was lost in the limbs with a resulting mutilating acropathy. Sudomotor function was also impaired. Motor function, tendon reflexes, kinaesthetic sensation and sensory nerve action potentials were normal. Sural nerve biopsy showed a selectively reduced small myelinated nerve fibre population. Corneal histology revealed neurotrophic keratitis. The classification of the hereditary sensory and autonomic neuropathies is discussed. This family represents a previously unrecognized variant.

Adult↗