Detection of integrins in human cataract lens epithelial cells and two mammalian lens epithelial cell lines.

AIM: To compare the incidence of various integrin subunits in human cataract anterior lens epithelial cells (A-LEC) and in two mammalian LEC lines. METHODS: Circular sections of anterior capsules with attached LEC were obtained during cataract surgery. Integrin subunits were immunolocalised in these anterior LEC and in a human and rabbit LEC line, using four monoclonal antibodies specific for subunits alpha2, alpha3, and alpha5, and beta subunit 2. RESULTS: All of these subunits were found in at least a proportion A-LEC samples as follows: alpha2 71%, alpha3 92%, alpha5 62%, and beta2 24%. The human LEC line was immunoreactive for alpha2 and alpha3 only. The rabbit lens epithelial cell line was immunoreactive for alpha5 but there was no staining for alpha2, alpha3, or beta2. CONCLUSION: The A-LEC and mammalian LEC lines showed a similarity in their pattern of integrin expression. As these integrins are receptors for extracellular matrix (ECM) components, they are likely to be associated with the attachment and migration of LECs that precedes capsular opacification. Therefore these cell lines may be useful in the elucidation of mechanisms involved the pathogenesis of capsule opacification.

Expression of CD18, CD49b, CD49c and CD49e on lens anterior capsules in human cataracts.

PURPOSE: To examine the lens epithelial cells obtained from the anterior lens capsules removed during cataract surgery and detect various subclasses of the cell surface adhesion molecules known as integrins. METHODS: The circular sections of anterior capsules with attached lens epithelial cells (LECs) were obtained during cataract surgery from 28 patients. The lens capsules were immunohistochemically stained. RESULTS: CD49b CD49c, CD49e, and CD18 were detected in varying degrees in specimens obtained from human cataractous lenses. The positive percentages were 33, 75, 33, and 20%, respectively. The most striking feature was the increasing staining profiles towards the edges of the capsules (away from the central part of the lens capsules) for CD49c, suggesting that the LECs showed higher immunoreactivity for this antibody. The immunoreactivity for CD49b and CD49e was weaker. This was absent for CD18 in the central part of the lens capsules. CONCLUSION: The positive expression of antibodies suggests that specific integrin subunits were expressed in LECs of human cataracts. These results suggest that lens epithelial cells expressing CD49b, CD49c, CD49e, and CD18 might be precursors in the process of anterior lens epithelial cell (A cell) adhesion, and hence play a role in anterior capsule opacification or in subsequent migration and a possible role in posterior capsule opacification.

Population-based cohort study of microbial keratitis in Scotland: incidence and features.

OBJECTIVE: To investigate the incidence and features of bacterial, fungal and protozoal keratitis in Scotland. DESIGN: Prospective, population-based cohort study of all persons who developed culture proven microbial keratitis over an 8 month period. SETTING: West of Scotland, UK. SUBJECTS: Approximately 3,000,000 population. MAIN OUTCOME MEASURES: Incidence and risk factors for microbial keratitis. METHODS: All patients were included who had presumed microbial keratitis from which bacteria, fungi or Acanthamoeba was isolated from the corneal scraping by the hospital laboratory using a standardised protocol. In addition, contact lens wearing patients with pathognomonic features of Acanthamoeba keratitis, who yielded a negative culture result when referred on chlorhexidine therapy, were included if Acanthamoeba could be cultured from their lens storage case. RESULTS: The overall annual incidence of culture-proven microbial keratitis was 0.26 per 10,000 with a rate of 1.8 per 10,000 for contact lens wearers (all types, soft and rigid). Based on a previous pilot study of 'presumed' microbial keratitis in Glasgow, it was possible to estimate the incidence of expected 'presumed' microbial keratitis as 0.36 per 10,000 overall and 2.44 per 10,000 for contact lens wearers (all types). The incidence for Acanthamoeba keratitis was 1.49 per 10,000 soft contact lens wearers; this infection was not detected in the absence of contact lens wear nor with use of gas permeable or rigid contact lenses. CONCLUSIONS: 'Presumed' microbial keratitis from all causes, in the adult population, was approximately three times less common in the West of Scotland (0.36 per 10,000) than would be expected from a comparable retrospective study from Minnesota, USA for the years 1980-1988 (1.1 per 10,000). It was rare (approximately one case expected in 2 million per year) in the absence of pre-existing corneal disease, cosmetic contact lens wear or trauma. Ocular surface disease was the underlying cause predisposing to infection in 58% of cases, with an incidence of 'presumed' keratitis of 0.21 per 10,000 population; the highest incidence was found in the elderly population. Contact lens wear was responsible for 38% of cases, emphasising the importance of preventive hygiene and effective disinfection in this group. The estimated incidence of 'presumed' microbial keratitis in the West of Scotland associated with cosmetic wear (daily and extended use) of soft contact lenses was significantly less (P<0.05) than that expected from a prospective study in New England, America in 1985 (266 per 10,000, rather than 8.05 per 10,000). However, the estimated incidence for presumed microbial keratitis for the West of Scotland associated with wearing soft contact lenses for cosmetic purposes in the daily wear modality (266 per 10,000) was less, but not significantly less, than that found in the prospective American study (4.20 per 10,000). The daily wear mode for contact lenses is almost universal in the West of Scotland, where extended wear has never been recommended. Extended wear has been shown in the USA to be associated with an incidence of presumed microbial keratitis between five and ten times higher than that associated with daily wear. This explains the lower incidence we have observed and a difference with the US study for overall infection rates but not when associated with daily wear alone. The incidence of proven Acanthamoeba keratitis found in the Scottish study among wearers of soft contact lenses for daily wear cosmetic purposes was exceptionally high at 1.49 per 10,000.

Acanthamoeba keratitis in Scotland: risk factors for contact lens wearers.

OBJECTIVE: To investigate risk factors for Acanthamoeba keratitis amongst contact lens wearers in Scotland. DESIGN: Patients with Acanthamoeba keratitis in the Scottish study, all of whom wore contact lenses, were compared with 46 healthy asymptomatic contact lens-wearing controls. They were all visited at home for contact lens and environmental microbiological sampling. In addition, all 288 optical practices in the West of Scotland were polled for contact lens types and disinfecting solutions sold in 1995, and a sample, each of whom fitted more than 500 contact lenses per year, were polled for a second time. Independently, a poll was commissioned by the Eyecare Information Service in July/August 1995 to estimate the numbers of contact lens wearers in Scotland and the UK. Industry was polled for numbers of each contact lens disinfecting regimen sold in Scotland in 1995. SETTING: West of Scotland, UK. SUBJECTS: All contact lens wearers among the 3 million population of the West of Scotland Health Board Areas. MAIN OUTCOME MEASURES: Risk factors for Acanthamoeba infection and recommendations for its prevention. RESULTS: When Acanthamoeba infection occurred, patients' home water systems were frequently (54%) found to be colonised by this amoeba. Patients more frequently washed their storage cases in tap water than controls (P<0.05) with resulting contamination, kept storage cases wet rather than air drying them (P<0.05), and had coliform bacteria cultured from the storage case (P<0.05) and had viable Acanthamoeba within the storage case (P<0.0001). Overall, patients were found to have significantly more risk factors than controls (P<0.0001). The noncompliant use of chlorine tablet disinfection, or failure to disinfect contact lenses at all, was associated with increased risk (P<0.05). Ionic high water content contact lenses (FDA group 4 material), when used without disinfection or with non-compliant use of low chlorine (Soflab) tablet-based disinfection, were associated with increased risk of Acanthamoeba infection (P<0.05). In log-linear modelling of risky hygiene behaviours associated with contamination of storage cases with Acanthamoeba, the most significant behaviour was found to be use of the less effective disinfection methods (chlorine tablets or no disinfection). However further investigation showed that these methods were associated with an increased probability of rinsing the storage case in tap water, so that these two behaviours are confounded in the group studied. CONCLUSIONS: Failure to disinfect contact lenses, non-compliant use of chlorine tablets and/or introduction of tap water rinsing of storage cases were associated with increased risk of Acanthamoeba infection. New multipurpose solutions and hydrogen peroxide gave the lowest risk of Acanthamoeba infection, with no statistically significant difference between them. Ionic high-water content (FDA group 4) contact lenses were at increased risk of being associated with Acanthamoeba keratitis if used without effective disinfection (multipurpose solutions or hydrogen peroxide). The use of domestic tap water for contact lens and storage case hygiene must be avoided, as a chain-of-causation' was identified from the home water supply.

Antimicrobial management of presumed microbial keratitis: guidelines for treatment of central and peripheral ulcers.

AIMS: To determine the quantitative relation between the major risk factors for microbial keratitis of previous ocular surface disease and contact lens wear and central and peripheral infiltration, often associated with ulceration, in order to establish a rational chemotherapeutic management algorithm. METHODS: Data from 55 patients were collected over a 10 month period. All cases of presumed microbial keratitis where corneal scrapes had been subjected to microbiological examination were included. Risk factor data and laboratory outcome were recorded. Antimicrobial regimens used to treat each patient were documented. RESULTS: 57 episodes of presumed microbial keratitis were identified from 55 patients, 24 male and 31 female. There were 30 central infiltrates and 27 peripheral infiltrates of which 28 were culture positive (73% of central infiltrates, 22% of peripheral infiltrates). 26 patients had worn contact lenses of whom 12 had culture positive scrapes (9/14 for central infiltrates, 3/12 for peripheral infiltrates). 31 patients had an ocular surface disease of whom five previous herpes simplex virus keratitis patients developed secondary bacterial infection. Anterior chamber activity and an infiltrate size > or = 4 mm2 were more common with culture positive central infiltrates than peripheral infiltrates (chi 2 test = 11.98, p < 0.001). CONCLUSIONS: Predisposing factors for "presumed" microbial keratitis, either central or peripheral, were: ocular surface disease (26/57 = 45.6%), contact lens wear (26/57 = 45.6%), and previous trauma (5/57 = 8.8%). Larger ulceration (> or = 4 mm2) with inflammation was more often associated with positive culture results for central infiltration. None of these four variables (contact lens wear, ocular surface disease, ulcer size, anterior chamber activity) were of intrinsic value in predicting if a peripheral infiltrate would yield identifiable micro-organisms. Successful management of presumed microbial keratitis is aided by a logical approach to therapy, with the use of a defined algorithm of first and second line broad spectrum antimicrobials, for application at each stage of the investigative and treatment process considering central and peripheral infiltration separately.

SCAN: a method of community collaboration.

Recent research has highlighted the complexity of the battered child syndrome. Clinical experience suggests that treatment of troubled families is a long-term process, draining financial resources of agencies and emotional resources of professionals. The need to provide support and case consultation to professionals working in the area of child abuse and neglect evolved in the establishment, in 1968, of the Suspected Child Abuse and Neglect (SCAN) Program at Children's Hospital, Pittsburgh, Pennsylvania. This program provides an effective method of intervention through identification, consultation, referral and follow-up of at-risk families. Weekly meetings offer multi-disciplinary case coordination, treatment recommendations, and a channel of communication for representatives of community agencies. This paper traces the history and present status of the SCAN Program, as well as the role of SCAN as a force for change of community attitudes.

Child abuse training: a community-based interdisciplinary program.

In the area of child abuse, a scarce resource is trained personnel. This paper describes a training program focusing on the need for individuals representing diverse disciplines to work together. Subjects discussed are the rationale and the organization process for a multidisciplinary, community-based training program; the formulation of the educational experience and the curriculum; evaluation measures; and the implementation of the program in a typical site. Various activities related to child abuse have been initiated in communities where training has occurred. Plans are to provide more intensive training in the treatment area for those professionals trained so far.