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Biomedical subjects

R W Acheson

Publications and source records attributed to R W Acheson.

At least 19 recordsLinked to original sources
PubMed2001

Immunogenetics and clinical phenotype of sympathetic ophthalmia in British and Irish patients.

BACKGROUND/AIMS: Sympathetic ophthalmia (SO) is a classic example of autoimmune disease where human leucocyte antigen (HLA) genomic associations could provide further understanding of mechanisms of disease. This study sought to assess HLA genetic polymorphism in British and Irish patients with SO, and to assess whether HLA gene variants are associated with clinical phenotype or disease severity. METHODS: High resolution DNA based HLA typing using polymerase chain reaction sequence specific primers was performed in 27 patients with SO and 51 matched healthy controls. Clinical phenotype and markers of disease severity were determined prospectively in 17 newly diagnosed patients and from medical record review and repeat clinical examination in 10 previously diagnosed patients. RESULTS: HLA-Cw*03 (p=0.008), DRB1*04 (p=0.017), and DQA1*03 (p=0.014) were significantly associated with SO. For class II alleles at higher resolution, only HLA-DRB1*0404 (relative risk (RR) = 5.6, p = 0.045) was significantly associated with SO. The highest relative risk for any of the associated haplotypes was with HLA-DRB1*0404-DQA1*0301 (RR=10.9, p=0.019). Patients with the DRB1*04-DQA1*03 associated haplotype were significantly more likely to develop SO earlier, with fewer inciting ocular trauma events, and to require more systemic steroid therapy to control inflammatory activity. CONCLUSIONS: Sympathetic ophthalmia is associated with HLA-DRB1*04 and DQA1*03 genotypes in white patients, similar to Japanese patients. Differences in DRB1*04 gene variant associations (-0404 in Britain and Ireland and -0405 in Japan) may have implications for HLA peptide binding in disease initiation. The DRB1*04-DQA1*03 haplotype is a marker of increased SO susceptibility and severity, as in Vogt-Koyanagi-Harada disease, which also has similar clinicopathological and HLA associations.

Alleles↗
PubMed1997

Prevalence of diabetic retinopathy in patients with diabetes mellitus diagnosed after the age of 70 years.

AIMS/BACKGROUND: A hospital based prevalence study was undertaken to estimate the prevalence of diabetic retinopathy (DR) in patients diagnosed as having diabetes mellitus after the age of 70 years. The prevalence of visually threatening retinopathy at the time of diagnosis of diabetes was also determined. The association between prevalence of DR and duration of diabetes mellitus, mode of treatment, HbA1c levels, presence of hypertension, and sex of patient was examined and a comparison was drawn between this study and earlier prevalence studies of DR in older type II diabetics. METHODS: Using data on the Irish Diabetic Retinopathy Register located in the Mater Misericordiae Hospital, Dublin, all patients who were diagnosed as having type II diabetes mellitus after the age of 70 years were invited to attend for ophthalmic review. Medical records were examined to determine the duration of diabetes mellitus, mode of treatment, recent HbA1c levels, and the presence of systemic hypertension. RESULTS: Of the 150 patients examined, 21 (14%) had some form of DR and 10 of these patients (6.6%) had visually threatening retinopathy or previously treated visually threatening retinopathy. Five patients (3.3%) presented with visually threatening retinopathy at the time of diagnosis of diabetes. Those patients with DR had a significantly higher median duration of diabetes (5.0 years) compared with those patients without DR (3.5 years). A significantly higher proportion of patients with DR required treatment with insulin and a correspondingly lower proportion of patients without DR were controlled on diet alone. There was no significant association between prevalence of DR and HbA1c levels, systemic hypertension, or sex of patient. There was a lower overall prevalence of DR in comparison with earlier studies. CONCLUSIONS: The prevalence of DR in these elderly type II diabetics is lower than than previously reported in patients with type II disease but a small percentage of patients had visually threatening retinopathy at presentation. Longer duration of diabetes and insulin use were associated with a significantly increased prevalence of DR. All elderly type II diabetic patients require thorough ophthalmic examination near to the time of first presentation and thereafter at regular intervals.

Aged↗
PubMed1997

Primary association of HLA-B51 with Behçet's disease in Ireland.

AIMS/BACKGROUND: While a primary association of HLA-B51 with Behçet's disease (BD) in Japanese and Mediterranean patients supports an immunogenetic predisposition, this link is unclear in north western Europe. This study assessed HLA associations with BD, and HLA-B51 with certain clinical characteristics, in the Republic of Ireland, which has an ethnically homogeneous population. METHODS: HLA-A, HLA-B, and HLA-DR typing was performed in 24 BD patients, conforming to International Study Group criteria, and in blood donors, as controls. Patient records were retrospectively reviewed and patients reassessed clinically. RESULTS: A highly significant HLA-B51 association (corrected exact p value = 0.002, relative risk = 6.3) with BD was determined, despite a low B51 prevalence (25%) in patients. No other HLA type was associated. There was a significant B51 link with male sex in BD patients but no association with age at first manifestation/diagnosis, eye involvement, cyclosporin A therapy, or poor visual acuity was determined. CONCLUSIONS: This study supports a HLA-B51 immunogenetic predisposition, similar to Japanese patients, in Irish BD in an ethnically homogeneous population in north western Europe. However, owing to a low prevalence of B51 positivity in BD patients in Ireland, a multifactorial pathogenesis is suggested.

Adult↗
PubMed1991

A randomized clinical trial of scatter photocoagulation of proliferative sickle cell retinopathy.

A randomized prospective clinical trial of argon laser scatter photocoagulation therapy for proliferative sickle cell retinopathy was performed on 116 patients (174 eyes) in Kingston, Jamaica. Ninety-nine eyes were treated with scatter photocoagulation and 75 eyes served as controls. The average length of follow-up was 42 months for the control eyes and 47 months for the treated eyes. Prolonged loss of visual acuity was statistically significantly reduced in the treated eyes. The incidence of vitreous hemorrhage was also significantly reduced in the treated eyes after controlling for the previously defined risk factors of vitreous hemorrhage and extent of proliferative sickle cell retinopathy at entry into the study. There were no complications associated with argon laser scatter photocoagulation. Scatter photocoagulation of proliferative sickle cell retinopathy is currently the most effective and safe way to treat patients with sea fan neovascularization.

Adult↗
PubMed1991

Treatment of iatrogenic choriovitreal neovascularisation in sickle cell disease.

The effect of scatter photocoagulation on the perfusion of iatrogenic choriovitreal neovascularisation (CVN) has been assessed by a randomised trial in 35 CVN lesions in 18 eyes with proliferative sickle retinopathy. No difference in size or vascularity of CVN lesions was apparent between the nine treated and nine control eyes over a median follow-up of 42 months. Scatter photocoagulation by the stated protocol was not effective in the treatment of CVN.

Adult↗
PubMed1990

Outcome of iatrogenic choroidal neovascularisation in sickle cell disease.

Choroidal neovascularisation developed in 62/66 (94%) eyes followed up for a mean period of 11.2 years after treatment with xenon arc feeder vessel coagulation for proliferative sickle retinopathy (PSR). In 27 eyes the neovascularisation was chorioretinal alone and in 35 eyes choriovitreal. Chorioretinal neovascularisation (CRN) was a benign complication but may convert to choriovitreal neovascularisation (CVN). Late sequelae of CVN included vitreous haemorrhage, posterior vitreous face fibrosis, and tractional retinal detachment. Visual loss (of greater than or equal to 3 Snellen lines for greater than or equal to 3 months) occurred in nine eyes affected by choroidal neovascularisation, though because of other pathology this could not always be attributed to the choroidal neovascularisation. The incidence of visual loss in CVN affected eyes was significantly greater, by survival curve analysis, than in eyes affected by CRN alone. Permanent visual loss from tractional retinal detachment definitely attributable to CVN occurred in 2/35 (6%) eyes.

Adolescent↗
PubMed1988

Argon laser trabeculoplasty in primary open-angle glaucoma--results in black Jamaican population.

A controlled, randomised, prospective trial of Argon laser trabeculoplasty (ALT) was carried out on 48 eyes of 30 black Jamaican patients with primary open-angle glaucoma. All eyes had uncontrolled intra-ocular pressures (greater than or equal to 22 mm Hg) despite medical therapy. Treatment was successful in controlling intraocular pressure in 68% of eyes after 12 months follow-up (p = 0.004). The average drop in intraocular pressure attributable to ALT was 6.6 mmHg. Argon laser trabeculoplasty is an effective adjunct in managing to control intraocular pressure in black Jamaican glaucoma patients.

Adult↗
PubMed1988

Patterns of visual loss in untreated sickle cell retinopathy.

Ophthalmic assessments of 120 patients with homozygous sickle cell (SS) disease and of 222 with sickle cell haemoglobin-C (SC) disease were conducted over a period of ten years. Visual acuity loss (V.A. less than or equal to 6/18) attributable to sickle cell retinopathy occurred in 10% of untreated eyes during a mean observation period of 6.9 years. Visual loss was strongly associated with proliferative sickle retinopathy (p less than 0.001) and most commonly resulted from vitreous haemorrhage, tractional retinal detachment and epiretinal membranes. The incidence of visual loss was 31 per 1000 eye-years observation among eyes with proliferative disease compared to 1.4 per 1000 eye-years observation among eyes with non-proliferative disease.

Adolescent↗
PubMed1988

Sickle cell retinopathy in Jamaican children: further observations from a cohort study.

Serial retinal examinations were performed in children aged 5 years and older and fluorescein angiography/angioscopy in children 6 years and older participating in a cohort study of sickle cell disease. There were 1229 patient years of observation among 389 children aged 5-13 years. Peripheral retinal vessel closure was present in approximately 50% of children with SS and SC genotypes at age 6 years and increased to affect 90% of children by age 12 years. A matched pair analysis, comparing groups with minimal and complete closure, indicated that complete closure was associated with significantly lower total haemoglobin and fetal haemoglobin levels and significantly lower weight in SS disease, whereas in SC disease the risk factors appeared to be high mean cell volume and low platelet count. Proliferative retinopathy was rare, occurring only once in an 8-year-old boy with SC disease, despite 592 patient years of observation in children over this age.

Adolescent↗
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

Epiretinal membranes in sickle cell disease.

Epiretinal membranes at the macula were seen in 4% of the eyes of 355 patients with homozygous sickle cell (SS) disease and sickle cell haemoglobin-C (SC) disease under the age of 60 years. The presence of proliferative sickle retinopathy (PSR), the extent of involvement of PSR, and vitreous haemorrhage all constitute risk factors for the formation of epiretinal membranes. The occlusion of PSR lesions by treatment appears to reduce the risk of epiretinal membranes being formed.

Adolescent↗