Intravitreal triamcinolone in cystoid macular edema due to uveitis and repeated surgery after a penetrating trauma.

PURPOSE: To test the effectiveness of intravitreal triamcinolone acetonide in treating macular edema due to multiple vitreoretinal surgical procedures and uveitis after a penetrating trauma with metallic foreign body retention in a 37-year-old man. METHODS: The patient received two intravitreal injections of triamcinolone acetonide-2 mg/0.05 mL and 4 mg/0.1 ml(-1) month apart. The 6-month follow-up included best-corrected visual acuity (BCVA) measurement and optical coherence tomography evaluation. RESULTS: After the first injection (2 mg) the foveal thickness (685 microm, as compared to a normal value of <165 microm) and the BCVA (20/200) remained unchanged with respect to the preinjection values; 1 week after the second injection (4 mg), the foveal thickness went down to 130 microm and the BCVA improved (20/80). Such results were unchanged at the 6-month control. No complications occurred. CONCLUSIONS: A 2 mg dose of triamcinolone acetonide did not improve the anatomic and functional status of the macula. A 4 mg dose markedly improved BCVA and reduced the macular thickness in this case of macular edema.

Perfluorohexyloctane (F6H8) induces structural modifications and increases apoptosis in rat primary retinal cultures.

The effects of perfluorohexyloctane (F6H8), recently investigated as a long-term artificial vitreous substitute, were studied in vitro, with the use of rat retinal cultures seeded on microporous inserts that allow the cell layer to be in contact with the material to be tested, on the apical side, and with the nutrient medium, on the basal side. After 72 h of treatment with F6H8, retinal cultures lost the characteristic two-layered organization with glial cells at the bottom and neuronal cells on top of them. They appeared to be composed of only one layer of polyhedrical, flattened, and disconnected cells. TUNEL assay revealed an evident increase in the percentage of apoptotic cells in F6H8-treated cultures (30.1 +/- 4.5), compared to control (10.3 +/- 2.6) and perfluoroctane-treated cultures (10.1 +/- 1.7). Immunolabeling of MAP-2, a protein of neuronal cytoskeleton, evidenced a marked loss of neurites. The results suggest that F6H8 is harmful to retinal cells in vitro and can therefore be potentially noxious to the retina as an artificial vitreous substitute.

Influence of dacron tissue thickness on the performance of the Pintucci biointegrable keratoprosthesis: an in vitro and in vivo study.

PURPOSE: In 1979 Pintucci developed a biointegrable keratoprosthesis with polymethylmethacrylate optical cylinder integrated with a Dacron tissue-colonizable supporting element to avoid the complications caused by the interaction between the haptic element and the eye. The purpose of this article is to compare the colonization of three Dacron fabrics (thicknesses of 0.25 mm, 0.6 mm, and 1.4 mm) in vitro and in vivo to optimize the device performance. METHODS: In vitro three different Dacron fabrics were cultured for 3 days with 3.5 x 10(5) human fetal lung fibroblasts and observed with a scanning electron microscope. In vivo three different Dacron fabrics were implanted on the sclera near the superior rectus insertion in the right eye of six albino rabbits and were observed after 4 days with light and scanning electron microscopy. RESULTS: In the in vitro experiments, the cells were preserved and their structure was found to be normal. The 0.25-mm thick fabric was coated only on the surface, and the other fabrics were colonized in three dimensions. In the in vivo experiments, the 0.25-mm thick fabric appeared coated only on its surface. The other fabrics were three-dimensionally colonized and the Dacron filaments appeared embedded in neovascularized connective tissue with minimal foreign body reaction. The 1.4-mm thick colonized fabric showed a substantial loss of pliability. CONCLUSION: Given that the 0.25-mm thick fabric was coated only by connective tissue, that the 0.6-mm and 1.4-mm thick fabrics were perfectly colonized, and that the 1.4-mm thick fabrics showed a substantial loss of pliability, the 0.6-mm thick fabric haptic part of the Pintucci keratoprosthesis is preferred. For 19 years, the 0.6-mm Dacron fabric Pintucci keratoprosthesis was implanted in 159 eyes with good results, overcoming the apparently inseparable difficulties represented by mechanical anchorage and biointegrability of a keratoprosthesis.

Alteration of organized structure of biofilm formed by Staphylococcus epidermidis on soft contact lenses.

The effect of a nonsteroidal antiinflammatory drug commercially available in eye drop form (sodium diclofenac) was assayed for its ability to affect biofilms formed by clinical Staphylococcus epidermidis isolates. Biofilms produced by one strain positive for a slime-associated antigen, suggested to be expressed by more virulent strains, was not affected by sodium diclofenac treatment. On the other hand, biofilm produced by the slime-positive, antigen-negative strain showed dramatic alterations already after short treatments with sodium diclofenac as reported for salicylate and other nonsteroidal drugs. Such results suggest further investigation of the possible use of sodium diclofenac drops in the treatment of ophthalmic infections in soft contact lens wearers.

PEDF (pigment epithelium-derived factor) promotes increase and maturation of pigment granules in pigment epithelial cells in neonatal albino rat retinal cultures.

Pigment Epithelium-Derived Factor (PEDF), purified from human retinal pigment epithelial (RPE) cell culture medium, is a neurotrophic factor which potentiates the differentiation of human Y-79 retinoblastoma cells and increases the survival of cerebellar granule cells. To investigate the effects of PEDF on non-transformed retinal cells, we used primary cultures of neonatal albino rat retinas, where the three principal cell types of the retinal layers (neuronal, glial and epithelial) were all present and focussed our attention on RPE cells, which are of special relevance for retinal pathophysiology. PEDF had a dramatic effect on these cells. They showed a modified phenotype, with larger dimensions, higher cytoplasmic spreading, presence of phagocytic vacuoles, development of wide intercellular contacts, and increase and maturation of pigment granules. These results suggest that PEDF may have a role in regulating RPE cell differentiation.

Perfluorodecalin modifies the pattern of cell arrangement and induces loss of neurites in rat retinal cultures.

Perfluorodecalin (PFD), a high specific weight, water-immiscible perfluorocarbon, previously studied as a potential blood substitute, now is used widely in the field of ophthalmic surgery as a tool for maneuvering intraocular tissues and as a short- or medium-term vitreous substitute. In in vivo experiments, several types of lesions in retinal tissue have been described in conjunction with long-term PFD treatment. To better evaluate the biological effects of PFD on retinal cells, we tested it on primary cultures of rat retina seeded on special cyclopore wells that allow the culture to be fed from the bottom side while the top side is in contact with the water-immiscible compound. We found that PFD changed the pattern of cell arrangement and induced loss of neurites. The modification of cell arrangement was less evident at the periphery of the wells where the amount of PFD, and consequently the pressure exerted, was lower. This observation suggests that the changes may be due more to a physical than to a toxic effect of PFD.

Effects of hyaluronan viscous materials on cell membrane electrical properties.

Hyaluronan [hyaluronic acid (HA)] has been implicated in various cellular processes such as proliferation, adhesion, migration, and differentiation. The secondary and tertiary structures of HA give it very important and unique viscoelastic properties. HA-composed materials are currently used intraocularly during ophthalmological surgery to facilitate surgical procedures and prevent tissue damage. To examine the effects of three viscous biomaterials composed of hyaluronan (Healon, IAL, and Biolon) used in ophthalmological surgery, the membrane electrical properties of the erythroleukemic K562 cell line exposed to these materials were investigated. Membrane conductivity, membrane permittivity, and the conductivity of the cytosol were evaluated using dielectric relaxation measurements in the radiofrequency range and fitting the experimental results to the general equations of the Maxwell-Wagner effect. The results demonstrate that while membrane permittivity and the conductivity of the cytosol are not significantly altered, the membrane conductivity of K562 cells exposed to all three biomaterials increases substantially and in a time-dependent manner with respect to untreated cells. These observations seem to indicate that hyaluronan perturbs ionic transport while it does not vary the type, quantity, or distribution of membrane components. In addition, the variations induced by these substances on the cell membrane are not dependent upon the molecular weight or on the biological origin of hyaluronan. These results may aid in elucidating the mechanisms involved in hyaluronan/cell membrane interaction and thus may provide a deeper understanding of the complications related to their use in ophthalmological surgery.

Visual disturbances associated with primary empty sella syndrome in patients with chronic renal failure.

After describing the main clinical features of primary empty sella syndrome and the main hormonal alterations in chronic renal failure, the authors report the results obtained in a group of 33 patients undergoing dialysis three times a week. Each patient had a complete ophthalmologic examination, with electroretinography and visual-evoked potentials, a complete radiologic examination, including skull stratigraphy (particularly of the sellar and parasellar bony structures), and a computed tomographic scan. In the whole group, visual acuity, ocular and lid motility, and visual fields were normal. In two patients, a slight bilateral papilledema, associated with a P100 latency increase and normal morphology and visual-evoked potentials, was reported. Two patients had initial unilateral papillary pallor associated with P100 amplitude alterations. In all four of these patients, radiologic examination showed a markedly pathologic sellar widening with thickening and double contour image of the floor. The report of a primary empty sella was confirmed by computed tomography in all four cases. The authors discuss the possible etiopathogenic mechanisms of the neuroophthalmologic symptoms associated with this syndrome.

Epidemiology of viral hepatitis in dialysis centers: a national survey.

Because of the great problem of viral hepatitis in hemodialysis patients, the Italian Society of Nephrology decided to perform a national epidemiologic survey. We contacted 467 nephrological centers by a questionnaire which let us have information on 25,746 uremic patients: 18,338 on HD, 2,250 on PD and 5,176 with kidney transplant, respectively 78.5% of the total Italian dialysed patients and 91.4% of the total transplanted patients. Statistical analyses were performed. HBV infections occur in 7.8% of the patients (2,008 cases) but considering that 485 cases became spontaneously negative, the true overall incidence of chronic carriers falls to 4.9%. The main causes of the infection are reported as transfusions (64.3%) and dialysis environment (12%). The vaccination program performed by 93.2% of the centers, obtained an efficacious seroconversion in 4,626 of 7,790 cases vaccinated: the vaccine currently most utilized is the recombinant type administered by means of 3 versus 4 boosters. In the 2nd part of the survey, we report information concerning the presence of nephropaties associated with HBV infections in nonuremic patients (208 cases). We present and discuss the clinical picture of the nephropaties, the hystologic bioptic pattern and the prognosis of the kidney pathology.