Biocompatibility of elastin-like polymer poly(VPAVG) microparticles: in vitro and in vivo studies.

Poly(L-valine-L-proline-L-alanine-L-valine-L-glycine) (VPAVG) is a new kind of proteinaceous polymer belonging to the Elastin-like family. These polymers are based on the recurrence of certain short peptide monomers that are considered as "building blocks" in the natural elastin. This smart thermoresponsive polymer has the ability to self-associate at physiological temperature to form aggregates with about 60% in water. This ability can be harnessed to prepare microparticles loaded with an active substance. The aim of this report is to evaluate, from the results of the experiment conducted, the biocompatibility of microparticles prepared from poly(VPAVG). We have studied the cytotoxic effects of microparticles, edema formation after subcutaneous injection (1 and 2.5 mg) in rats (n = 6), and also intraocular tolerance after the intravitreal injection of 2.5 mg of poly(VPAVG) microparticles into pigmented rabbits (n = 12). The polymer did not induce any cytotoxicity or nonspecific depression of cellular respiration on macrophages under the range of polymer concentrations investigated in this study (20, 30, 40, and 60 mg/mL). We observed no inflammatory response to microparticles after subcutaneous injection in the hind-paw of rats, with no significant differences between the control group (PBS) and experimental groups. Anterior and posterior segment signs were evaluated after intraocular injection of poly(VPAVG) microparticles. Only a few eyes (2/11) of the experimental group presented inflammation signs at day 28 postinjection. Nevertheless, 45% (5/11) of the eyes receiving microparticles showed tractional retinal detachment. The results observed in this work suggested certain fibroblastic activity induced by poly(VPAVG) microparticles after their intraocular injection.

[Outer retinal edema or multifocal choroiditis after retinal detachment surgery. A case report]. / Edema retiniano externo o coroiditis multifocal tras la cirugía del desprendimiento de retina. A propósito de un caso.

CASE REPORT: We describe a case of a woman who, in the postoperative period of retinal detachment, developed an ophthalmoscopic picture which could correspond to abnormal outer retinal swelling or multifocal choroiditis. Ophthalmoscopic appearance consists of multiple yellowish subretinal lesions in the temporal area of the posterior pole with a cobblestone appearance. DISCUSSION: The two entities are extremely rare complications of rhegmatogenous retinal detachment surgery, with very similar funduscopic appearance. The first one consists of localized pockets of subretinal fluid remaining after retinal detachment surgery. Multifocal choroiditis is an inflammatory process related to various causes.

[Ghost cell detection in vitreous cytology: clinico-pathological correlation]. / Detección de células fantasma en citologías vítreas: correlación clínico-patológica.

PURPOSE: To determine the prevalence of detection of ghost cells (GCs) in vitreous hemorrhages (VHs) and correlate it with the development of ghost cell glaucoma. To compare our results with those previously reported. METHODS: Retrospective analysis of clinical records and vitreous cytology reports (cytospin and direct paraffin embedding) from patients undergoing vitrectomy for VH at Instituto Universitario de Oftalmobiología Aplicada and University Hospital, Valladolid, for the last 2 years. RESULTS: 76 VHs have been analysed; 45 corresponded to proliferative diabetic retinopathy and the remainder to several pathologies. GCs have been detected in 18 cases (25%) (4 out of 76 specimens were excluded): 14 were phakic and 4 pseudophakic. Most of 76 VHs lasted more than 2 months. No case of ghost cell glaucoma was detected, neither previously nor after vitrectomy. CONCLUSIONS: The frequency of detection of GCs in vitreous cytology may vary according to the cytologic technique. In contrast with the information previously reported, ghost cell glaucoma is an unfrequent disease, particularly after vitrectomy, probably because of a better removal of hemorrhagic debris from the vitreous cavity nowadays. Nevertheless, this diagnosis should not be overlooked.

[Treatment of the massive suprachoroidal hemorrhages]. / El tratamiento de las hemorragias supracoroideas masivas.

PURPOSE: To analyze the anatomical and functional results obtained in post- surgical suprachoroidal hemorrhages treated from 1998 to 2000 and to review the information on the series of this complication that have been published during the last five years and which included at least 10 patients. METHODS: A retrospective analysis of the medical records of patients with suprachoroidal hemorrhages at the Instituto Universitario de Oftalmobiología Aplicada (IOBA) - University Hospital of Valladolid. Bibliographic search by Med-Line/Pub Med from 1995 to 2000 was performed. RESULTS: 8 patients who fulfill these criteria have been treated and 8 papers, also complying with the criteria, have been found. CONCLUSIONS: The functional and anatomic results of post-surgical suprachoroidal hemorrhages are still poor, even though the prognosis seems to have improved in the last 20 years. The standardized classification of massive suprachoroidal hemorrhages based on severity and the standardization of the follow-up would improve these results.

[Comparison of different techniques for cytologic analysis of vitreous specimens]. / Comparación de diferentes técnicas de análisis citológico en muestras vítreas.

PURPOSE: To assess the efficacy of four methods to study the cytology of vitreous samples, and to evaluate the most efficient for routine analysis and immunocytochemical staining. METHODS: Diluted and undiluted vitreous samples of 87 consecutive patients suffering vitreoretinal surgery for different diseases were analysed. The specimens were centrifugated and then processed through four different procedures: agar sandwich (29 cases), direct paraffin embedding (33 cases), cytospin preparations (82 cases) and cytoblock (8 cases). RESULTS: Evaluable material was obtained in: agar sandwich 18 out of 29 cases (62%), direct paraffin embedding 32 out of 33 cases (96.9%), cytospin 72 out of 82 cases (87.8%) and cytoblock 1 out of 8 cases (12.5%). CONCLUSIONS: Direct paraffin embedding and cytospin are the most efficient procedures for routine purposes. Agar sandwich technique seems to be useful for studying small pieces of tissue. Direct paraffin embedding and agar sandwich technique seems to be valuable for immunocytochemistry. After 8 cases processed with cytoblock, our experience did not show valuable results for processing vitreous samples.

[Retinal shortening: the most severe form of proliferative vitreoretinopathy (PVR)]. / Acortamiento retiniano: la forma más grave de la vitreorretinopatía proliferante (VRP).

PURPOSE: To identify the clinical characteristics of patients developing retinal shortening due to intraretinal PVR. METHODS: Observational and retrospective cohort study on 110 PVR patients operated on between 2000 and 2001. During surgery, after removing epiretinal membranes and ruling out the presence of subretinal membranes, a perfluorocarbon liquid was injected. Those cases in which retinal flattening was not accomplished, were considered intraretinal PVR (group 1). Those in which retinal flattening allowed endolaser application, were taken as the control group (group 2). Clinical features of both groups were compared by chi-square test. RESULTS: 60 cases (54.5%, CI 95%: 40.5-68.5) showed retinal shortening (group 1). In 24 cases (21.8%, CI 95%: 12.9-30.7) complete retinal flattening was accomplished (group 2). In 26 cases (23.6%), evaluation was inconclusive. In 9 out of the 60 cases of group 1 (15%) a retinectomy was necessary to reattach the retina. Differences between both groups were not statistically significant for any of the clinical variables. However, the number of retinal detachments of more than 60 days of evolution was significantly higher in retinectomized eyes (20.7%) than in group 1 (3.7%) (p=0.04). CONCLUSIONS: Retinal shortening is a relatively frequent phenomenon in PVR. Further studies are necessary to characterize this clinical presentation of PVR and its pathogenesis.

Protocol for mitomycin C use in glaucoma surgery.

PURPOSE: To evaluate the results of a protocol described for mitomycin C (MMC) use in trabeculectomy or combined surgery (phacoemulsification and trabeculectomy). METHODS: A total of 143 eyes (60 trabeculectomies and 83 combined surgeries) of 124 patients were divided into four groups: group 1 (without MMC); group 2 (with 0.1 mg/ml MMC); group 3 (with 0.2 mg/ml MMC), and group 4 (with 0.4 mg/ml MMC). Two-minute MMC was used in every case in groups 2, 3 and 4. The results were analysed after 1 year of follow-up. Intraocular pressure (IOP) and complications were evaluated. Successful IOP control was defined when IOP was <21 mmHg and <16 mmHg if advanced glaucoma was present, always without additional medical treatment. RESULTS: Mean preoperative IOP decreased from 24.60 mmHg (SD 1.40 mmHg) to 13.47 mmHg (SD 0.37 mmHg) (p < 0.00001), 12 months postoperatively. Control in IOP was achieved in 79.02% of eyes. No significant differences were found in final mean IOP values (p > 0.196) or in postoperative complications (p > 0.120) in groups 2, 3 and 4. CONCLUSION: With the protocol described, a selection of concentration of MMC has been made in different clinical forms of glaucoma. No significant differences in IOP control and postoperative complications were noticed among the groups.