Biomedical subjects

Paul Mitchell

Publications and source records attributed to Paul Mitchell.

At least 91 records · Page 5Linked to original sources

PubMed2005

Pterygium, pinguecula, and 5-year incidence of cataract.

PURPOSE: To assess longitudinal associations between pterygium, pinguecula, and 5-year incident cataract. DESIGN: Population-based cohort study. METHODS: The Blue Mountains Eye Study examined 3,654 residents aged > or =49 years during 1992 to 1994 and reexamined 2,335 (75.1% of survivors) 5 years later. Slit-lamp examination recorded pterygium and pinguecula. Cataract was assessed using masked grading of lens photographs. Incidence was assessed in participants without cataract at baseline. Eye-specific data were analyzed using generalized estimating equation models, adjusting for age, sex, smoking, diabetes, and corticosteroid use. RESULTS: Pinguecula was associated with a borderline-significant, increased risk of developing cortical cataract (adjusted odds ratio, 1.3; 95% confidence interval, 1.0 to 1.7). We found no significant association between baseline pterygium and the incidence of cortical, nuclear, or posterior subcapsular cataract. CONCLUSIONS: Longitudinal data from the same study population provide weak support for cross-sectional associations between pinguecula and cortical cataract previously reported from our study.

Cataract↗

PubMed2005

Intraocular pressure over the clinical range of blood pressure: blue mountains eye study findings.

PURPOSE: To quantify the relation of blood pressure (BP) and intraocular pressure (IOP) across the clinical range of BP in an older phakic population not using glaucoma medications. DESIGN: Cross-sectional population-based study METHODS: Seated BP and applanation IOP were measured, and their relation was assessed in regression models. RESULTS: Mean IOP of the two eyes increased linearly from 14.3 mm Hg for systolic BP <110 mm Hg to 17.7 mm Hg for systolic BP > or =200 mm Hg, a 3.4-mm Hg excursion over this range. Mean IOP also increased from 15.2 mm Hg for diastolic BP <70 to 18.4 mm Hg for diastolic BP > or =120, a similar variance. There were no changes after age and multivariate adjustments for IOP or after excluding undiagnosed glaucoma cases. CONCLUSION: A 3-mm linear IOP increase over the clinical spectrum of BP levels was evident; this variance is greater than with most other systemic and ocular parameters.

Blood Pressure↗

PubMed2005

Numerical confusion errors in ishihara testing: findings from a population-based study.

PURPOSE: To describe the prevalence of numerical confusion errors in Ishihara testing in a representative sample of Australian children. DESIGN: Cross-sectional, population-based study. METHODS: The Sydney Myopia Study examined a representative stratified random cluster sample of 1,741 children (aged 6 years) attending 34 schools in Sydney, Australia (response rate, 78.9%), including color vision tests in 1,735 children. Those with any color vision defects (n = 33; 1.9%; 97% boys) were excluded. Responses for each Ishihara plate were recorded. RESULTS: Numerical confusion errors were made by 75.8% of children with normal color vision; there was no gender difference. Plates 3 and 7 were particularly prone to numerical confusion errors; 48.4% and 40.8%, respectively, of children misread these plates. CONCLUSION: Numerical confusion errors in the Ishihara test were relatively common in children with normal color vision. The frequency of such errors could indicate an inherent deficiency in this commonly used test.

Child↗

PubMed2005

Impact of birth parameters on eye size in a population-based study of 6-year-old Australian children.

PURPOSE: To study the effect of birth parameters, including birth weight, birth length, and birth head circumference on ocular dimensions in 6-year-old children. DESIGN: Cross-sectional study. METHODS: A stratified random cluster sample of 6-year-old Sydney school-students (n = 1765) were participants in this study. Children had ocular dimensions measured with non-contact methods (Zeiss IOLMaster, Zeiss, Meditec-AG, Jena, Germany). Information on birth weight, height, and head circumference was derived from a questionnaire. RESULTS: After adjusting for cluster, age, and gender, children with birth weight <2500 g had mean axial length 22.46 mm (95% confidence interval [CI], 22.20-22.72) and mean corneal radius 7.70 mm (CI 7.61-7.79). This compared with axial length 22.80 mm (CI 22.70-22.90) and mean corneal radius 7.85 mm (CI 7.81-7.89) for children with birth weight > or =4000 g. Axial length and corneal radius were also related to birth length and head circumference. Refraction, however, was unrelated to birth size. CONCLUSION: Birth parameters have a lasting effect on eye size but not on spherical equivalent refraction.

Biometry↗

PubMed2005

Prevalence and associations of epiretinal membranes in the visual impairment project.

PURPOSE: To determine the prevalence and factors associated with epiretinal membranes in a random sample of the population aged 40 years and older in Victoria, Australia. DESIGN: Population-based cross-sectional study. METHODS: Detailed eye examinations, including retinal photographs, were conducted in 1992 and 1997 in 3271 people (83% of the eligible) in Melbourne and 1473 (92% of the eligible) in rural Victoria. Eyes present with either cellophane macular reflex (CMR) or preretinal macular fibrosis (PMF) were classified as having epiretinal membranes. Eyes with both CMR and PMF present were classified as having PMF. Age-standardized prevalence rates and 95% confidence limits were calculated by the direct methods using Segi's world population. RESULTS: Epiretinal membranes were observed in 253 of 4313 participants (6.0%; 95% confidence interval [CI] 5.2 to 6.7), bilaterally in 19%. Prevalence increased significantly by age group (0.5% for 40 to 49 years, 2.6% for 50 to 59 years, 9.4% for 60 to 69 years, 15.1% for 70 to 79 years, and 11.3% for 80 years and older). Prevalence was similar in males and females after adjusting for age. The overall age- and gender-standardized prevalence of CMR was 4.8% (95% CI 4.0 to 5.6) and PMF was 1.7% (95% CI 1.2 to 2.3). A decrease in visual acuity (<6/6) was significantly associated with idiopathic PMF (odds ratio [OR] 1.9; 95% CI 1.0 to 3.6) and CMR (OR 1.5; 95% CI 1.1 to 2.0) after adjusting for age. CONCLUSIONS: The prevalence of epiretinal membranes was similar to that reported in other population-based studies. Population shifts in the age distribution to older ages could lead to an increase in mild visual impairment caused by epiretinal membranes.

Adult↗

PubMed2005

Accuracy of the Lang II stereotest in screening for binocular disorders in 6-year-old children.

PURPOSE: To assess the accuracy of the Lang II stereotest in screening for strabismus, amblyopia, and anisometropia in 6-year-old children. DESIGN: Cross-sectional population-based study. METHODS: The Sydney Myopia Study examined 1765 6-year-old children (78.9% of eligible) who were identified by random cluster sampling of 34 schools in Sydney, Australia. Sensitivity and specificity of the Lang II stereotest was determined by best stereoacuity. Cycloplegic autorefraction, assessment of visual acuity, and ocular motility were conducted. RESULTS: Test sensitivity ranged from 21.4% for anisometropia (> or =1.0 diopter) to 31.3% for amblyopia. The detection rate for new cases of amblyopia ranged from 20% to 40%; the detection rate for new cases of strabismus was 30%. Specificity was >98% in all three conditions. Children with false-negative results included newly diagnosed cases of strabismus (14 of 25 children) or amblyopia (5 of 12 children). CONCLUSION: The Lang II stereotest, when used alone, has very limited value as a screening test of binocular dysfunction.

Amblyopia↗

PubMed2005

Patterns of spectacle use in young Australian school children: findings from a population-based study.

PURPOSE: To describe the patterns of spectacle use in a population-based sample of Australian Year 1 school children (mostly aged 6 years). METHODS: Logarithm of the minimum angle of resolution (logMAR) visual acuity was measured in both eyes before and after pinhole correction, and using spectacles if worn. Cycloplegic autorefraction (cyclopentolate) and detailed dilated fundus examination were performed. Visual impairment was defined as visual acuity <40 logMAR letters (ie, <20/40 Snellen equivalent). Myopia was defined as spherical equivalent (SE) refraction < or = -0.50 diopters (D), and hyperopia as SE refraction > or = +2.0D, deemed significant when > or = +3.0D. Astigmatism was defined as cylinder > or =1.0D and anisometropia as SE refraction difference between the two eyes at least 1.0D. RESULTS: One thousand seven hundred forty predominantly 6-year-old school children were examined during 2003 to 2004. Spectacle use was documented in 77 children (4.4% of sample). Uncorrected visual impairment was found in the worse eye of 71 children (4.1%) and refractive error accounted for the majority (69.0%). Astigmatism was the most common refractive error causing visual impairment, accounting for 46.5%. Hyperopia, with or without astigmatism, was the most frequent reason for spectacle use, documented in 40.3%. Spectacle use in the absence of significant refractive error, amblyogenic risk factors, or visual impairment was noted in 26 children (33.8% of spectacle wearers). The prescription of spectacles could have benefited a further 26 children (1.5% of sample), mostly for correction of astigmatism. CONCLUSION: This study documents a significant disparity between spectacle use and need. Astigmatism was the most common cause of visual impairment due to refractive error.

Child↗

PubMed2005

Direct quantitation of T cell signaling by laser scanning cytometry.

Current flow cytometric technology allows quantitative assessment of surface and intracellularly expressed molecules on isolated cells. However, the need to disrupt tissues prevents correlation of phenotypic expression with anatomical location. In contrast, immunohistochemistry in conjunction with conventional or confocal microscopy allows localisation of staining, but little in the way of quantitation. The laser scanning cytometer (LSC) allows a combination of both approaches, as it can apply quantitative flow cytometric laser technology to intact tissue. The purpose of this protocol is to describe in vitro and ex vivo methods for quantifying cell signaling molecule expression and activation within antigen-specific T cells by laser scanning cytometry.

Animals↗

PubMed2005

Retinal vessel diameter and open-angle glaucoma: the Blue Mountains Eye Study.

PURPOSE: To examine the relationship between open-angle glaucoma (OAG) and retinal vessel diameter among baseline participants in the Blue Mountains Eye Study. DESIGN: Population-based cross-sectional study. PARTICIPANTS: The study included 3654 persons older than 49 years, representing 82.4% of permanent residents living in an area west of Sydney. METHODS: Participants had a detailed eye examination, including automated perimetry and stereo optic disc photography. A computer-assisted program measured retinal vessel diameters from digitized photographs of right eyes. MAIN OUTCOME MEASURES: Open-angle glaucoma was diagnosed from matching visual field defects and optic disc cupping, without reference to intraocular pressure (IOP) level. Ocular hypertension was defined as IOP of >21 mmHg in either eye, without matching glaucomatous optic disc and field changes. Average retinal vessel diameters, measured from right eyes, were summarized as arteriolar and venular equivalents. The lowest quintile of the arteriolar equivalent or arteriole-to-venule ratio was used to define generalized retinal arteriolar narrowing. RESULTS: The study included 3314 participants, after excluding those with incomplete data or nonglaucomatous optic nerve disease. Of persons included, 59 (1.8%) had evidence of glaucomatous damage affecting the right eye, 3065 (92.5%) had no damage to either eye, and 163 (4.9%) had ocular hypertension. Right eyes with glaucomatous damage had significantly narrower retinal arteriolar diameters (183+/-2.6 microm) than eyes without glaucoma (194+/-0.4 microm, P = 0.0001) or eyes with ocular hypertension (195+/-1.6 microm, P = 0.0002), after adjusting for age, mean arterial blood pressure, and other confounding variables, including refraction. Right eyes with glaucomatous damage were at least 2 times more likely to have generalized retinal arteriolar narrowing than eyes without glaucoma (odds ratio, 2.7; 95% confidence interval, 1.5-4.8). CONCLUSIONS: These population-based data suggest that generalized retinal arteriolar narrowing, an indicator of localized vascular change, is significantly associated with optic nerve damage caused by OAG. It is not clear whether such a retinal arteriolar change reflects an ischemic process leading to optic nerve damage or results from loss of retinal neurons secondary to glaucoma.

Aged↗

PubMed2005

Is renal impairment a predictor of the incidence of cataract or cataract surgery? Findings from a population-based study.

PURPOSE: To explore the relationship between creatinine clearance, an estimate of glomerular filtration rate, and 5-year incidence of cataract and cataract surgery. DESIGN: Population-based cohort study. PARTICIPANTS: Of the 3654 participants (aged 49 years or older) of the Blue Mountains Eye Study (BMES I) baseline examination (during 1992 to 1994), 2334 (75%) were reexamined after 5 years from 1997 to 1999 (BMES II). METHOD: Risk factor data were collected for all participants at baseline (BMES I). Assessment of renal function was based on estimated creatinine clearance (C(Cr)) calculated with the Cockcroft-Gault formula, adjusted for body surface area, and expressed in ml/minute/1.73 m2. Cataract incidence was determined from graded photographs. The association between renal function and incidence of cataract and cataract surgery was analyzed by logistic regression. MAIN OUTCOME MEASURES: Incidence of nuclear, cortical, and posterior subcapsular cataract, and cataract surgery. RESULTS: Mean C(Cr) +/- standard deviation was 60+/-13 ml/minute/1.73 m2. The overall 5-year incidence of nuclear, cortical, and posterior subcapsular cataract was 35.7% (417 of 1167 participants at risk), 16.7% (274 of 1641), and 4.3% (77 of 1790), respectively. Cataract surgery was performed in 6.8% (144 of 2123) of participants. There were no significant associations of renal function with incident nuclear (odds ratio [OR], 1.0; 95% confidence interval [CI], 0.99-1.02), cortical (OR, 1.0; CI, 0.98-1.01), and posterior subcapsular cataract (OR, 1.0; CI, 0.99-1.04) after adjusting for multiple risk factors. After adjusting for age, gender, and dark brown iris color, moderate or worse renal impairment (C(Cr) <60 ml/minute/1.73 m2) compared with normal or mildly impaired function (C(Cr) > or =60 ml/minute/1.73 m2) was significantly associated with incident cataract surgery (P<0.05), but the effect depended on age. Participants younger than 60 years of age with moderate to severe renal impairment had increased odds of incident cataract surgery (OR, 2.75; CI, 1.06-7.14), but this OR decreased with age. In participants 80 years old or older, the OR was 0.34 (CI, 0.11-1.10). CONCLUSIONS: There were no significant effects of renal function on the incidence of cataract of any type. The effect of moderate or worse renal impairment on incident cataract surgery depended on age. However, the interpretation of this effect is uncertain because of additional factors that may be involved in patients having surgery.

Aged↗

PubMed2005

Cardiovascular risk factors for retinal vein occlusion and arteriolar emboli: the Atherosclerosis Risk in Communities & Cardiovascular Health studies.

OBJECTIVE: To examine the associations of retinal vein occlusion and arteriolar emboli with cardiovascular disease. DESIGN: Population-based cross-sectional study. PARTICIPANTS: Pooled from the Atherosclerosis Risk in Communities Study (n = 12,642; mean age, 60 years) and the Cardiovascular Health Study (n = 2824; mean age, 79 years). METHODS: Retinal vein occlusion and arteriolar emboli were identified from a single nonmydriatic retinal photograph using a standardized protocol. Photographs were also graded for arteriovenous nicking and focal arteriolar narrowing. All participants had a comprehensive systemic evaluation, including standardized carotid ultrasonography. MAIN OUTCOME MEASURES: Retinal vein occlusion and arteriolar emboli. RESULTS: Prevalences of retinal vein occlusion and arteriolar emboli were 0.3% (n = 39 cases) and 0.2% (n = 34 cases), respectively. After adjusting for age, retinal vein occlusion was associated with hypertension (odds ratio [OR], 2.96; 95% confidence interval [CI], 1.43-6.14), systolic blood pressure (BP) (OR, 4.12; 95% CI, 1.40-12.16; highest quartile vs. lowest), diastolic BP (OR, 2.64; 95% CI, 1.07-6.46; highest quartile vs. lowest), carotid artery plaque (OR, 5.62; 95% CI, 2.60-12.16), body mass index (OR, 3.88; 95% CI, 1.23-12.18; highest quartile vs. lowest), plasma fibrinogen (OR, 3.29; 95% CI, 1.08-10.02; highest quartile vs. lowest), arteriovenous nicking (OR, 4.09; 95% CI, 2.00-8.36), and focal arteriolar narrowing (OR, 5.17; 95% CI, 2.59-10.29). After adjusting for age, retinal arteriolar emboli were associated with hypertension (OR, 3.14; 95% CI, 1.44-6.84), systolic BP (OR, 3.46; 95% CI, 1.13-10.65; highest quartile vs. lowest), prevalent coronary heart disease (OR, 2.33; 95% CI, 1.01-5.42), carotid artery plaque (OR, 4.62; 95% CI, 1.85-11.57), plasma lipoprotein (a) (OR, 3.69; 95% CI, 1.20-11.41; highest quartile vs. lowest), plasma fibrinogen (OR, 3.09; 95% CI, 0.98-9.76; highest quartile vs. lowest), and current cigarette smoking (OR, 3.08; 95% CI, 1.47-6.47). Approximately a quarter of participants with retinal vein occlusion and arteriolar emboli had evidence of carotid artery plaque as defined from ultrasound. CONCLUSIONS: Retinal vein occlusion and retinal arteriolar emboli are associated with carotid artery disease, hypertension, and other cardiovascular risk factors.

Aged↗

PubMed2005

Visual acuity and the causes of visual loss in a population-based sample of 6-year-old Australian children.

PURPOSE: To describe the distribution of visual acuity and causes of visual loss in a representative sample of Australian schoolchildren. DESIGN: Population-based cross-sectional study. PARTICIPANTS: One thousand seven hundred thirty-eight predominantly 6-year old children examined during 2003 to 2004. METHODS: Logarithm of the minimum angle of resolution (logMAR) visual acuity was measured in both eyes before and after pinhole correction and with spectacles if worn. Cycloplegic autorefraction (cyclopentolate) and detailed dilated fundus examination were performed. MAIN OUTCOME MEASURES: Visual impairment was defined as any (visual acuity <20/40; <40 letters) or severe (visual acuity < or =20/200; 0-5 letters) for both better and worse eyes. Myopia was defined as spherical equivalent (SE) refraction < or =-0.50 diopters (D), and hyperopia as SE refraction > or =+2.0 D, deemed significant when > or =+3.0 D. Astigmatism was defined as cylinder > or =1.0 D and anisometropia as SE refraction difference between eyes at least 1.0 D. Amblyopia was defined as corrected visual acuity <0.3 logMAR units (<20/40; <40 letters) in the affected eye not attributable to any underlying structural abnormality of the eye or visual pathway, together with a 2-logMAR line difference between the eyes and presence of an amblyogenic risk factor. RESULTS: The mean visual acuity of this sample was 20/25 (49.3 letters). Uncorrected visual impairment was found in the better eye of 23 children (1.3%) and in the worse eye of 71 children (4.1%). The prevalence was higher in girls than boys and among children of lower socioeconomic status. Refractive error was the most frequent cause, accounting for 69.0%, followed by amblyopia (22.5%). Astigmatism was the principle refractive error causing visual impairment and was frequently uncorrected. Presenting visual impairment (using current glasses if worn) was found in the better and worse eyes of 15 children (0.9%) and 54 children (2.8%), respectively. This was mainly due to under corrected or uncorrected refractive error. CONCLUSIONS: This study has documented a relatively low prevalence of visual impairment in a population of Australian children. Uncorrected astigmatism and amblyopia were the most frequent causes.

Child↗

PubMed2005

Methods for a population-based study of myopia and other eye conditions in school children: the Sydney Myopia Study.

PURPOSE: The Sydney Myopia Study will establish the prevalence of myopia and other eye diseases in a large representative sample of Sydney school children. It will also examine the relationship between myopia and potential modifiable risk factors and will assess potential gene-environment interactions by examining parents and siblings. METHODS: The target population is a stratified random cluster sample of 1750 Year 1 (age 6 years) and 1500 Year 7 (age 12 years) students from Sydney metropolitan schools. Procedures (comprehensive parent-administered questionnaire and examination) involve standardized protocols to allow for comparison with international population-based data. Examinations include a detailed assessment of visual acuity, cover testing for strabismus, identification of amblyopia, slit-lamp examination, non-contact ocular biometry and cycloplegia (cyclopentolate) followed by autorefraction, optical coherence tomography, retinal thickness measurement, digital mydriatic retinal photography and aberrometry. CONCLUSIONS: The Sydney Myopia Study design and methodology will ensure valid findings on ocular development and health in a large representative sample of Sydney school children, for comparison with other population-based refraction data.

Adolescent↗

PubMed2005

Vision and self-rated health: longitudinal findings from an older Australian population.

PURPOSE: To assess temporal associations between vision and self-rated health. METHODS: We examined 3654 Australian residents (82.4% response) aged 49+ years in the Blue Mountains Eye Study, during 1992 to 1994, and re-examined 2334 in 1997 to 1999. Change in vision was defined if baseline and 5-year visual acuity (VA) changed by > or =10 letters (2 lines). Change in self-rated health was defined if overall health ranking (excellent, good, fair, poor) changed by > or =1 step. RESULTS: Of 2285 participants with data from both examinations, 59.8%, 23.9%, and 16.3% reported unchanged, declined, and improved self-rated health, respectively. Among persons whose self-rated health declined, the proportions with a decline in presenting VA, no change, or improvement were similar (25.2%, 23.8% and 22.5%, respectively, p for trend = 0.5). Among participants with decline, no change, or improvement in self-rated health, a similar magnitude in the age-sex adjusted mean VA decline (-1.0 to -2.7 letters) was observed. After adjusting for age, sex, hospitalizations, and incident chronic conditions, declining VA was not associated with increased decline in 5-year self-rated health (multivariate-adjusted odds ratio 0.99, 95% CI 0.75-1.30). CONCLUSION: There were no parallel 5-year changes in self-rated health and vision in this population.

Aged↗

PubMed2005

Vision and hearing impairment in aged care clients.

PURPOSE: To determine the frequency of sensory impairments among aged care clients. METHODS: We examined 188 persons aged 65-99 years being evaluated for aged care services at a geriatric assessment center, west of Sydney, Australia. Visual acuity was measured using a LogMAR chart. Visual impairment was defined in the better eye: mild < 20/40 to > or = 20/80, moderate < 20/80 to > or = 20/200, and severe < 20/200. Hearing function was assessed by portable pure-tone air-conduction audiometry. Hearing loss was defined using average hearing thresholds in the better ear: mild > 25 to < or = 40 decibels (dB), moderate > 40 to < or = 60dB, and severe > 60dB. RESULTS: Vision, hearing, or both were randomly tested in 96, 93, and 49 aged care clients, respectively. Vision impairment was found in 30.2% of clients. Distance vision could be improved with pinhole in 16.7% of 84 clients with presenting VA < 20/20. Moderate to severe hearing loss was present in 50.5%. Combined sensory impairment was detected in 22.5% of persons having both tests. The age-standardized proportions with vision impairment was 25.6%, higher than the rate (17.4%) found in the Blue Mountains Eye Study (BMES) community population, but lower than the 37.7% prevalence reported from the BMES nursing home sample. Hearing impairment was also more common in aged care clients (28.1% vs 17.5%). CONCLUSIONS: This study suggests a high prevalence of sensory impairment among older persons transitioning from independent community living to institutionalized care.

Aged↗

PubMed2005

Effects of caffeine on intraocular pressure: the Blue Mountains Eye Study.

PURPOSE: To examine the relationship between coffee and caffeine intakes and intraocular pressure (IOP). MATERIALS AND METHODS: The Blue Mountains Eye Study examined 3654 participants aged 49+ years in an area west of Sydney, Australia. A detailed medical history questionnaire included average daily intakes of coffee and tea. The eye examination included Goldmann applanation tonometry and automated perimetry. Participants using glaucoma medications or who had previous cataract or glaucoma surgery or signs of pigmentary glaucoma/pigment dispersion, were excluded. Mean and maximum IOP calculations were used. RESULTS: Participants with open-angle glaucoma (OAG) who reported regular coffee drinking had significantly higher mean IOP (19.63 mm Hg) than participants who said that they did not drink coffee (16.84 mm Hg), after multivariate adjustment, P = 0.03. Participants consuming > or = 200 mg caffeine per day had higher mean IOP (19.47 mm Hg) than those consuming < 200 mg caffeine per day (17.11 mm Hg), after adjusting for age, sex, and systolic blood pressure (SBP), P = 0.06. This association did not reach statistical significance after multivariate adjustment. No association between coffee or caffeine consumption and higher IOP was found in participants with ocular hypertension (OH) and those without open-angle glaucoma. CONCLUSIONS: In participants with open-angle glaucoma, this study identified a positive cross-sectional association between coffee consumption/higher caffeine intakes and elevated intraocular pressure.

Blood Pressure↗

PubMed2005

Cataract surgery in patients with age-related maculopathy: preoperative diagnosis and postoperative visual acuity.

PURPOSE: To report the reliability in detecting age-related maculopathy (ARM) lesions before cataract surgery and postoperative visual acuity (VA) in cataract surgery patients with ARM. METHODS: Medical records of surgical patients in a large public hospital, west of Sydney, were reviewed retrospectively. Detection of ARM lesions was compared before and after surgery to determine sensitivity and specificity of preoperative diagnoses. Postoperative VA was assessed 4 weeks after surgery. RESULTS: Data were available for 721/784 eyes (92.0%) of 656 patients aged 60 years or older. ARM lesions were detected in 98 eyes (13.6%) before and 92 eyes (12.8%) after surgery. Sensitivities for detecting late ARM lesions, soft drusen and retinal pigment epithelium abnormalities preoperatively were 100%, 94% and 69%, respectively. Corresponding specificities were 100%, 100% and 77%, respectively. Postoperative VA achieved or remained 6/12 or better in 81.6% of eyes. CONCLUSION: A high sensitivity and specificity in detecting late ARM lesions and soft drusen preoperatively, and a good postoperative VA outcome is achievable in patients with preoperative early ARM lesions.

Aged↗

PubMed2005

The LEE1 promoters from both enteropathogenic and enterohemorrhagic Escherichia coli can be activated by PerC-like proteins from either organism.

The PerC protein of enteropathogenic Escherichia coli (EPEC), encoded by the pEAF plasmid, is an activator of the locus of enterocyte effacement (LEE) pathogenicity island via the LEE1 promoter. It has been assumed that the related LEE-containing pathogen enterohemorrhagic E. coli (EHEC) lacks PerC-dependent activation due to utilization of an alternative LEE1 promoter and lack of a perC gene. However, we show here that EPEC PerC can activate both the EPEC and EHEC LEE1 promoters and that the major transcriptional start site is similarly located in both organisms. Moreover, a PerC-like protein family identified from EHEC genome analyses, PerC1 (also termed PchABC), can also activate both promoters in a manner similar to that of EPEC PerC. The perC1 genes are carried by lambdoid prophages, which exist in multiple copies in different EHEC strains, and have a variable flanking region which may affect their expression. Although individual perC1 copies appear to be poorly expressed, the total perC1 expression level from a strain encoding multiple copies approaches that of perC in EPEC and may therefore contribute significantly to LEE1 activation. Alignment of the protein sequences of these PerC homologues allows core regions of the PerC protein to be identified, and we show by site-directed mutagenesis that these core regions are important for function. However, purified PerC protein shows no in vitro binding affinity for the LEE1 promoter, suggesting that other core E. coli proteins may be involved in its mechanism of activation. Our data indicate that the nucleoid-associated protein IHF is one such protein.

5' Flanking Region↗