Silicone oil concentrates fibrogenic growth factors in the retro-oil fluid.

AIM: To determine whether silicone oil concentrates protein and growth factors in the retro-oil fluid. METHODS: A laboratory analysis of intraocular fluid and vitreous specimens obtained from patients undergoing removal of silicone oil, revision vitrectomy, or primary vitrectomy for macular hole, proliferative vitreoretinopathy (PVR), or retinal detachment. Patients were prospectively recruited from routine vitreoretinal operating lists. Vitreous cavity fluid and vitreous samples were analysed for the presence of transforming growth factor beta (TGF-beta2), basic fibroblast growth factor (bFGF), interleukin 6 (IL-6), and total protein using either commercially available enzyme linked immunosorbent assays (ELISA) or protein assay kits. RESULTS: The median levels of bFGF, IL-6, and protein in the retro-oil fluid were raised (p<0.05) compared to all the other vitreous and vitreous cavity fluid samples. bFGF, IL-6, and protein levels were raised in PVR vitreous compared to non-PVR vitreous. TGF-beta2 levels were not significantly raised in retro-oil fluid or in PVR vitreous. CONCLUSIONS: The concentration of fibrogenic (bFGF) and inflammatory (IL-6) growth factors and protein is raised in retro-silicone oil fluid. This may contribute to the process of retro-oil perisilicone proliferation and subsequent fibrocellular membrane formation.

Stable rAAV-mediated transduction of rod and cone photoreceptors in the canine retina.

Recombinant adeno-associated virus (rAAV) vectors are attractive candidates for the treatment of inherited and acquired retinal disease. Although rAAV vectors are well characterized in rodent models, a prerequisite to their clinical application in human patients is the thorough evaluation of their efficacy and safety in intermediate animal models. In this study, we describe rAAV-2-mediated expression of GFP reporter gene in retinal cells following local vector delivery in dogs. Subretinal delivery of rAAV.CMV.GFP was performed unilaterally in eight normal dogs from 6 weeks of age. The area of retinal transduction was maximized by the optimization of surgical techniques for subretinal vector delivery by pars-plana vitrectomy and the use of fine-gauge subretinal cannulae to create multiple retinotomies. rAAV-2 vectors mediated efficient stable reporter gene expression in photoreceptors and retinal pigment epithelial cells. We found efficient transduction of cone photoreceptors in addition to rods in both the canine retina and after subretinal vector delivery in another intermediate animal model, the feline retina. GFP expression in dogs was confined to the area of the retinal bleb and was sustained in cells at this site for at least 18 months. Electroretinography demonstrated a modest reduction in global rod-mediated retinal function following subretinal delivery of rAAV.CMV.GFP. Three of the eight animals developed delayed-onset intraocular inflammation, in two cases associated with a serum antibody response to GFP protein. We conclude that rAAV-2 vectors mediate efficient sustained transgene expression in rod and cone photoreceptors following subretinal delivery in this intermediate animal model. The possibility of adverse effects including intraocular immune responses and reduced retinal function requires further investigation prior to clinical applications in patients.

Proliferative vitreoretinopathy-developments in adjunctive treatment and retinal pathology.

Proliferative vitreoretinopathy (PVR) remains a difficult management problem despite advances in vitreoretinal surgery. There is still a significant incidence of PVR in rhegmatogenous retinal detachment and other forms of retinal disease. Surgery for PVR now has a high anatomical success rate although visual results are often disappointing. The use of adjunctive treatments to prevent cellular proliferation holds promise for the prevention of PVR or recurrences after surgery. Control of proliferation and strategies aimed at improving visual outcome are important areas of future research in PVR and other forms of retinal disease. Studies of the intraretinal and peri-retinal pathology of PVR have demonstrated characteristic changes which may have a significant influence on visual outcome and surgical management.

Animal models of retinal detachment and reattachment: identifying cellular events that may affect visual recovery.

Retinal detachment continues to be a significant cause of visual impairment, either through the direct effects of macular detachment or through secondary complications such as subretinal fibrosis or proliferative vitreoretinopathy. Animal models can provide us with an understanding of the cellular mechanisms at work that account for the retinopathy induced by detachment and for the generation of secondary effects. As we understand the mechanisms involved, animal models can also provide us with opportunities to test therapeutic agents that may reduce the damaging effects of detachment or improve the outcome of reattachment surgery. They may also reveal information of use to understanding other causes of blindness rooted in retinal defects or injuries. Understanding the effects of detachment (and reattachment) are likely to become even more important as surgeons gain skills in subretinal surgical techniques and macular translocation, both of which will generate short-lived detachments. Here we discuss the fundamental events that occur after detachment, present changes associated with reattachment, and discuss retinal changes that may affect the return of vision.

Laser pointers revisited: a survey of 14 patients attending casualty at the Bristol Eye Hospital.

AIMS: The largest clinical series of laser pointer exposures to date is described, to document any long term visual sequelae and assess objectively the visual threat from transient ocular exposure. METHODS: 14 cases were collected prospectively and triaged by ophthalmic nurses before referral to an ophthalmologist for a complete ophthalmic examination. Regardless of the need for clinical follow up, all patients were contacted by telephone at a mean interval of 10.5 months following exposure to inquire about new or persisting symptoms. RESULTS: 11/14 cases presented within 24 hours of exposure and 5/14 incidents were reported to the police. Reduced acuity in the affected eye compared with the contralateral were documented in 5/14 cases. The commonest physical sign was a punctate epitheliopathy, seen in 5/14 cases, and the commonest symptom was ocular discomfort, reported by 11/14 patients. There were no consistent retinal findings. Follow up by telephone survey revealed that two patients were wearing new glasses, but had not been refracted before the exposure; one had intermittent ocular discomfort; the remaining 11 were asymptomatic. CONCLUSIONS: This study is reassuring to the ophthalmology community and the general public in failing to demonstrate consistent, long term damaging effects of transient ocular exposure to laser pointer beams.

Spectrophotometric determination of tellurium after adsorption of its morpholine-4-carbodithioate on microcrystalline naphthalene.

A rapid spectrophotometric method has been developed for microdetermination of Te(IV) after co-precipitation of its morpholine-4-carbodithioate complex on microcrystalline naphthalene and subsequent dissolution in chloroform. The molar absorptivity at 415 nm is 9.18 x 10(3) l.mole(-1).cm(-1). Beer's law is obeyed over the range 5-75 mug of Te(IV); 25.0 mug of Te(IV) in 10.0 ml of final solution gives a mean absorbance of 0.180 with a relative standard deviation of 0.55%. The method has been tested for determination of tellurium in some alloys and synthetic mixtures.

Plamar Dermatoglyphics in Psorlasis-a Pilot Study.

Palmar dermatoglyphics was studied in 24.female cases of psoriasis and 25 normal 'females. TWO parameters were studied. Mean values ridge count from tritadial point to point 'of core between psoriasis and normals showed statistically significant difference in right palm digit I and left palms digit IV. Study of metric analyses of palm between psoriasis and normals showed that mean values of -vertical distance from a-d to the axial triradius on left side showed a statistically significant difference. The role of study of almat p.