Expression of proteins associated with cell-matrix adhesion in proliferative vitreoretinopathy designed by Dispase model.

PURPOSE: During recent years, the interaction of cell surface molecule, extracellular matrix proteins, and cytoskeletal elements has been a topic for research for the purpose of understanding the mechanisms of pathologic conditions. This study aims to evaluate the expression of CD44, as a cell surface adhesion molecule; fibronectin (FN), as an extracellular and a cell surface protein; vinculin and actin/á-smooth muscle actin (alfa-SMA), as cytoskeletal elements; and the interactions of these proteins in the microenvironment of proliferative vitreoretinopathy (PVR). METHODS: This experimental study was designed by the intravitreal Dispase model in rabbits and proteins' expression were evaluated via immunohistochemical staining. RESULTS: As a cell surface protein, CD44 expression was determined in only four eyes focally and weakly, but in a small number of cells. Among the cytoskeletal proteins, vinculin expression was the most extensive and the strongest in intensity in epi- and subretinal membranes. Alpha-SMA expression was mostly present within small foci of cells. Fibronectin expression was determined in some of the eyes only faintly. CONCLUSIONS: Vinculin seems to be involved in PVR pathogenesis. Variability in co-distribution of the expression of vinculin, FN, and alfa-SMA reflects the dynamic interactions evolving between cell and extracellular matrix during the epi- and subretinal membrane formations. The results of this study were determined not to be in support of the assumption that CD44 has a functional role in the pathogenesis of PVR.

Experimental tractional retinal detachment: an immunohistochemical study.

PURPOSE: This study investigated the pathogenesis of tractional retinal detachment associated with proliferative vitreoretinopathy in an experimental model, using immunohistochemical staining. METHODS: To produce tractional retinal detachment in rabbit eyes, homologous cultured fibroblasts obtained from the gluteal muscle fascia were injected intravitreously. Right eyes of 20 rabbits in the study group, and 7 rabbits in the control group were followed for 26 days at weekly intervals with indirect ophthalmoscopy and fundus photographs. RESULTS: During the follow-up period grade III tractional retinal detachment developed in 11 eyes, grade II in six, and grade 1 in three eyes. The spindle-shaped cells contributed predominantly to the development of epiretinal membrane, and a smaller number of round small and large cells. In 10/17 grade II and III eyes, spindle-shaped cells had vimentin, 7/10 had actin, 5/17 had GFAP, 4/17 had S-100 protein immunoreactivity. Round small and large cells expressed S-100 protein, GFAP and actin in 5/17 eyes. Epiretinal membrane appeared to be formed by spindle-shaped fibroblast-like cells and small and large round glia-like cells. Actin positivity of spindle-shaped and round cells was taken as a marker of contractile elements of the cells and their locomotional features. CONCLUSIONS: These features are believed to be involved in contraction of the membrane and retinal detachment.

[Evaluation of conjunctival cultures in various eye infections]. / Cesitli göz enfeksiyonlarinda konjonktiva kültürlerinin degerlendirilmesi.

1550 conjunctival cultures taken between 1985-1988 were evaluated retrospectively. Among 455 cultures with positive growth, bacterial agents seen in their order of occurrence were Staphylococcus epidermidis (35.82%), Streptococcus pneumonia (19.34%) and Staphylococcus aureus (18.46%), respectively. Moreover, the distribution of agents in 185 cases with complete clinical records were discussed in the light of data found in the literature.

[Stability of cefazolin sodium as eyedrops in various solutions]. / Cesitli sivilar ile göz damlasi olarak hazirlanan sefazolin sodyumun stabilitesi.

Cephazolin sodium prepared with four different solutions (NaCl 0.9%, Protagent, Liquifilm and phosphate buffer) to be used as eye drops, was evaluated as to its physicochemical features at +4 degrees C, +37 degrees C and at room temperature and its activity in terms of minimal inhibition concentration. In conclusion, cephazolin sodium prepared with artificial tears at acidic pH can be kept for 3 days at room temperature and at +4 degrees C without any loss of its activity.

[Effect of levodopa therapy on visual evoked potentials and visual acuity in amblyopia]. / Der Effekt der Llevodopatherapie auf das visuell evozierte Potential und die Sehschärfe in der Amblyopie.

Amblyopia represents the most common form of visual impairment in children, affecting approximately 2% of the population. To determine the efficacy of the dopamine agonist levodopa for childhood amblyopia, a double-masked, placebo-controlled randomised study was performed on 32 amblyopic children with central fixation between 4 and 17 years. Subjects received 2 mg/kg levodopa benzeraside or placebo 3 times per day over a 1 week period. Estimates of visual acuity for each eye (Snellen visual acuity) were obtained, and pattern-shift visually evoked potentials (VEP) were examined by an opthalmologist and a neurologist. At the end of dosing regimens, the levodopa group was significantly improved in visual acuity by 1.4 lines and pattern VEP amplitudes. No changes could be detected after placebo administration. One week after the termination of the treatment, Snellen line acuity and pattern VEP amplitude were decreased to pretreatment levels. The transient effect of levodopa points to a long-term treatment with the substance. Our results should therefore encourage further long-term clinical trials investigating the therapeutic potential of levodopa in amblyopia.