L. M. T. Collum

Daunomycin as an inhibitor of human lens epithelial cell proliferation in culture

Abstract Posterior capsule opacification is still a major complication of both extracapsular cataract extraction and phacoemulsification. We evaluated the effects of the antiproliferative agent daunomycin on cultured human and bovine lens epithelial cell viability and proliferation. After ten minutes of exposure, low concentrations of the agent markedly inhibited the proliferation of both cell types. The calculated LD50 for the drug against human cells was 2.20 &mgr;g/ml and against the bovine cells was 0.38 &mgr;g/ml. The bovine cells appeared to be slightly more susceptible to the drug’s effects, although this difference was not marked. Our results indicate that daunomycin is a potent inhibitor of both human and bovine lens epithelial cells in the laboratory.

Effect of topical cyclosporin A on conjunctival T cells in patients with secondary Sjögren's syndrome.

The effect of topical cyclosporin A on conjunctival T cells was studied in nine patients with secondary Sjögrens disease. Patients had conjunctival biopsies performed before and after a 6-week course of topical cyclosporin. Epithelium and substantia propria in the Sjögrens patients before treatment showed significantly more CD4 + cells than specimens taken from nine age- and sex-matched controls. Following treatment with topical cyclosporin, there was a significant reduction in the number of CD4 + cells in both the conjunctival epithelium and substantia propria. Despite the fact that the treatment resulted in immunopathological improvement, the clinical benefit was not as favorable. Our results suggest that topical cyclosporin may have a local immunosuppressive effect on the conjunctiva in patients with Sjögrens disease.

Risk factors, microbiological findings, and clinical outcomes in cases of microbial keratitis admitted to a tertiary referral center in Ireland.

Aim: To identify the risk factors for, and to report the microbiological findings and clinical outcomes of, severe microbial keratitis (MK). Methods: This was a retrospective study of all cases of presumed MK admitted to a tertiary referral center over a 2-year period (September 2001 to August 2003). Data recorded included demographic data, details relating to possible risk factors, results of microbiological studies, clinical findings at presentation, and clinical and visual outcomes. Results: Ninety patients were admitted with a diagnosis of presumed MK during the study period. The mean age of patients was 45 ± 32 years, and the male to female ratio was 47:43 (52.2%:47.7%). Predisposing risk factors for MK included contact lens wear (37; 41.1%), anterior segment disease (19; 21.1%), ocular trauma (13; 14.4%), systemic disease (5; 5.6%), and previous ocular surgery (1; 1.1%). Cultured organisms included gram-negative bacteria (17; 51.5%), gram-positive bacteria (11, 33.3%), acanthamoeba (2; 6.1%), and fungi (1; 3%). Visual acuity improved significantly after treatment [mean best-corrected visual acuity (±standard deviation) at presentation: 0.76 (±0.11); mean best-corrected visual acuity at last follow-up: 0.24 (±0.07); P < 0.001]. Secondary surgical procedures were required in 18 (20%) cases, and these included punctal cautery (1; 1.1%), tissue glue repair of corneal perforation (2; 2.2%), tarsorrhaphy (9; 9.9%), Botulinum toxin-induced ptosis (1; 1.1%), penetrating keratoplasty (3; 3.3%), and evisceration (2; 2.2%). Conclusions: Contact lens wear remains a significant risk factor for severe MK. MK remains a threat to vision and to the eye, but the majority of cases respond to prompt and appropriate antimicrobial therapy.

Homozygosity mapping and linkage analysis demonstrate that autosomal recessive congenital hereditary endothelial dystrophy (CHED) and autosomal dominant CHED are genetically distinct

BACKGROUND Congenital hereditary endothelial dystrophy (CHED) is a corneal dystrophy characterised by diffuse bilateral corneal clouding resulting in impaired vision. It is inherited in either an autosomal dominant (AD) or autosomal recessive (AR) manner. The AD form of CHED has been mapped to the pericentromeric region of chromosome 20. Another endothelial dystrophy, posterior polymorphous dystrophy (PPM), has been linked to a larger but overlapping region on chromosome 20. A large, Irish, consanguineous family with AR CHED was investigated to determine if there was linkage to this region. METHODS The technique of linkage analysis with polymorphic microsatellite markers amplified by polymerase chain reaction (PCR) was used. In addition, a DNA pooling approach to homozygosity mapping was employed to demonstrate the efficiency of this method. RESULTS Conventional genetic analysis in addition to a pooled DNA strategy excludes linkage of AR CHED to the AD CHED and larger PPMD loci. CONCLUSION This demonstrates that AR CHED is genetically distinct from AD CHED and PPMD.

Quantification of the ultraviolet radiation (UVR) field in the human eye in vivo using novel instrumentation and the potential benefits of UVR blocking hydrogel contact lens.

BACKGROUND/AIMS Certain degenerative eye conditions occur predominantly nasally, at the limbal region, and are associated with solar ultraviolet radiation (UVR) induced damage. The relative contribution to the in vivo ocular flux of (a) the reflection of UVR incident on the skin of the nose onto the nasal limbus, and (b) the focusing of UVR incident on the temporal side of the cornea onto the nasal limbus were examined. METHODS A novel photodiode sensor array was used to measure the UVR field across the eye. In addition, a novel spectrometer set-up was used to measure the spectrum of radiation refracted across the cornea. The efficacy of UVR blocking hydrogel contact lenses in filtering incident UVR was assessed in vivo. RESULTS Qualitative and quantitative data indicated an increase nasally of UVR. Photodiode readings showed a net UVR increase from the temporal to the nasal side. Transmission curves showed that most UVR incident on the limbal region is either absorbed by, or transmitted through, the ocular tissues. This radiation is filtered by UVR blocking soft contact lens. CONCLUSIONS An increased UVR flux on the nasal side of the eye, due to reflection off the nasal skin, was identified in vivo. Any UVR passing through the cornea is either absorbed by the conjunctiva and/or transmitted through it onto the sclera where it is absorbed. UVR blocking hydrogel contact lenses can eliminate these sources of UVR.

Acyclovir ointment plus topical betamethasone or placebo in first episode disciform keratitis.

Thirty patients with first episode disciform keratitis and with no previous steroid exposure were randomly assigned to double blind treatment with 3% acyclovir ointment and 0.1% betamethasone (Betnesol) drops or acyclovir ointment and matching placebo. In the steroid group 14 of the 15 patients healed in a mean time of 21.8 days. In the placebo group eight of the 13 patients healed in a mean time of 34.5 days. The difference in mean healing time between the two groups was significant (p < 0.05). The cumulative rate of healing was also quicker in the steroid group when compared with the placebo group (p < 0.001). Other clinical parameters improved more favourably in the combination treatment group. Four patients, two in either group, experienced a mild transient punctate epitheliopathy, but no other serious adverse effects were noted. There has been no significant difference in the recurrence rate between the two groups after a mean follow-up period of approximately 3 years.

Randomised double-blind trial of bromovinyldeoxyuridine (BVDU) and trifluorothymidine (TFT) in dendritic corneal ulceration.

The results of a randomised double-blind clinical trial of 0.1% bromovinyldeoxyuridine (BVDU) and 1% trifluorothymidine (TFT) in 60 patients with corneal dendritic ulceration are presented. There was no significant difference between BVDU and TFT in terms of numbers of ulcers healed (p = 0.61), mean healing time (p = 0.065), and cumulative healing rate (p = 0.058). No serious side effects were observed, though transient stinging was recorded in five patients receiving TFT and in three patients receiving BVDU. One patient in the group treated with TFT developed a punctate epitheliopathy.

Adherence of human lens epithelial cells to conventional poly(methyl methacrylate), heparin-surface-modified, and polyHema lenses

Abstract We developed an in vitro model to assess the adherence of human lens epithelial cells to three types of intraocular lenses: poly(methyl methacrylate) (PMMA), heparin‐surface‐modified PMMA (HSM‐PMMA), and polyHema. Lenses were incubated with a fixed number of human lens epithelial cells. Adherent cells were counted after 72 hours in culture. Scanning electron microscopy showed significantly fewer cells adhering to the HSM‐PMMA and polyHema lenses than to the PMMA lenses (P <.01). Repeat experiments on cell lines established from different donors confirmed these findings.

Growth characteristics of human lens epithelial cells in culture: effect of media and donor age

The effect of different concentrations of fetal calf serum (FCS) on the proliferative capacity of human and bovine lens epithelial cells in culture was evaluated. The effect of donor age on the maximum number of passages achieved using thirty eight individual cultures was also studied. The donor ages ranged from 1–88 years. Fifteen percent FCS was found to be the optimum concentration for both human and bovine cells. The two cell types demonstrated very similar responses across the spectrum of concentrations used. Correlation analysis revealed a significant (p < 0.05) negative correlation between donor age and maximum number of cell passages achieved.

The role of common viral ocular pathogens in Thygeson’s superficial punctate keratitis

Background/aims: The aetiology of Thygeson’s superficial punctate keratitis (TSPK) remains elusive. A viral aetiology has been suggested by the absence of bacterial infection and clinical resemblance to other viral keratopathies. We report the results of polymerase chain reaction analysis for the detection of herpes simplex virus (HSV) 1 and 2, herpes zoster virus, varicella zoster virus (VZV) and adenovirus from corneal epithelial samples from patients with active signs and symptoms of TSPK. Methods: Schirmer strip impressions were taken from the epithelium of eight patients with a known history of TSPK and symptoms and signs of active disease. Three patients were recruited as positive controls (two with herpes simplex keratitis and one with herpes zoster ophthalmicus). Samples from a further three patients acted as negative controls. All 14 samples underwent polymerase chain reaction testing for HSV 1, HSV 2, VZV and adenovirus. Results: DNA corresponding to the expected viral DNA was amplified from all three positive control samples. The three negative control samples showed no evidence of viral DNA. Similarly, all samples from patients with TSPK showed no evidence of the presence of HSV 1, HSV 2, VZV or adenovirus. Conclusion: We conclude that HSV, VZV and adenovirus are not present in the epithelium of patients with TSPK. These results are considered in light of existing theories regarding the aetiology and treatment of this condition.