Lens Subluxation after Plasmin and SF6 Injections in Rabbit Eyes (original) (raw)
Related papers
American Journal of Ophthalmology, 2002
To investigate the ultrastructure of the vitreoretinal interface following an intravitreal injection of plasmin. Plasmin (2 U/0.1 ml) was injected into the vitreous cavity of five postmortem human eyes. The five fellow eyes received phosphate-buffered saline and served as controls. After incubation at 37 degrees C for 30 minutes, the globes were placed in fixative and hemisected. Specimens for scanning and transmission electron microscopy were obtained using a corneal trephine. All plasmin-treated eyes showed complete vitreoretinal separation with sparse collagen fibrils covering the inner limiting membrane. All control eyes showed an attached cortical vitreous. At the vitreous base, there was no cleaving effect. The retinal morphology of plasmin-treated eyes was unchanged. Plasmin induces a cleavage between the vitreous cortex and the inner limiting membrane without morphologic alteration of the retina.
Molecular vision, 2012
To investigate the efficacy of plasmin and sulfur hexafluoride (SF(6)) on the vitreoretinal junction, as well as the long-term safety in the eye and effect on the recipient's general health after application in the eye. The study design included four groups of rabbits with three animals in each group. Group 1 received an intravitreal injection (IVI) of plasmin and SF(6) in the right eye; group 2 received an IVI of plasmin in the right eye; group 3 received an IVI of SF(6) in the right eye; and group 4 received an IVI of balanced salt solution in the right eye, which served as a normal control. Long-term safety (up to approximately three months) after plasmin and/or SF(6) injection was evaluated morphologically by clinical examination, histology, and immunohistochemistry, and functionally by electroretinograms (ERGs). General health evaluations after intravitreal injection included the assessment of weight gain, food intake, body temperature, and complete blood count analysis. Pl...
American journal of …, 2005
To investigate the effect of exogenous plasmin administration on the activity of endogenous matrix metalloproteinase-2 (MMP-2) in rabbit and human vitreous.Experimental animal study and interventional case series.Human plasmin was injected into rabbit eyes. The active/pro-MMP-2 ratio in vitreous samples was calculated using the gelatin zymography. Scanning electron microscopy (SEM) was performed to observe the retinal surface. To evaluate the time course of MMP-2 activity, vitreous samples were collected after the injection of 0.5 IU of plasmin, and the active/pro-MMP-2 ratio was calculated in the same manner. Immunohistochemical analysis was performed to confirm the presence of MT1-MMP in the rabbit eye. Human vitreous samples obtained from vitreous surgeries were also used for similar studies.The active/pro-MMP-2 ratios in the vitreous after the injection of 0.25 IU or 0.5 IU of plasmin were significantly higher than that of the control (P < .05). SEM demonstrated that plasmin-treated eyes showed a smooth retinal surface that was dose-dependent. Time course evaluation of the active/pro-MMP-2 ratio in the vitreous after the administration of 0.5 IU of plasmin found a significant difference between the 5 and 15 minutes data points compared with that seen for the control. Immunohistochemical study revealed the presence of MT1-MMP in the inner retina. In human samples, the active/pro-MMP-2 ratio after the plasmin injection was significantly higher than the ratio observed before injection.Our results suggested that activation of endogenous MMP-2 by exogenous plasmin is associated with the induction of posterior vitreous detachment.
Recombinant tissue plasminogen activator following paediatric cataract surgery
British Journal of Ophthalmology, 2000
Background-The use of recombinant tissue plasminogen activator (r-TPA) has been advocated in the treatment of postsurgical fibrinous membrane formation following cataract surgery in adults. Its use in paediatric cases is not well documented. Method-A retrospective review of paediatric cataract extractions performed at Moorfields Eye Hospital between 1 January 1997 and 4 April 1999 was carried out. Results-Cataract extractions were performed in 37 patients, 22 in males 15 in females. Four (9.2%) underwent intracameral injection of 25 µg r-TPA. They were all females of Afro-Caribbean origin. The time to injection varied from 4-14 days, mean 7.2 days. Complete resolution of the fibrinous membrane was seen in all cases. There were no complications by the 3 month follow up. Conclusion-r-TPA may be used safely and eVectively at a dose of 25 µg for the treatment of severe fibrinous membranes following paediatric cataract extraction. It aided the visual recovery of the children and also allowed a reduced regimen of topical steroid therapy to be used postoperatively. (Br J Ophthalmol 2000;84:983-986) Strabismus and
Fibrinolysis, 1996
Plasminogen activators (PA) play an important role not only in fibrinolysis but also in a variety of processes including tissue remodelling. The stroma of the cornea is a dense connective tissue characterized by its transparency. Healing, degenerative, and inflammatory processes lead to corneal opacification. In an attempt to determine the role of PA in corneal physiology, we have analysed the secretion of PA and plasminogen activator inhibitor (PAl-l) by corneal fibroblasts in vitro. We show that in contrast to other adult fibroblasts, corneal fibroblasts secrete both tissue-type plasminogen activator (t-PA) and urokinase-plasminogen activator (u-PA). Epithelial growth factor and basic fibroblast growth factor stimulated t-PA secretion whereas transforming growth factor-13 decreased t-PA and increased PAl-1 secretion, t-PA was secreted in the surrounding medium while u-PA remained mostly associated to the cell surface. The production and secretion of t-PA are characteristic of corneal fibroblasts and could be implicated in matrix remodelling and the maintenance of corneal transparency.
Archivos de la Sociedad Espanola de Oftalmologia
To determine the effectiveness of intravitreal plasmin injection in the treatment of macular epiretinal membranes (MEM) and vitreomacular traction syndrome (VMTS) without associated pars plana vitrectomy. Design: Interventional, prospective, case series pilot study. Patients: Seven patients were enrolled in the study, 4 with MEM and 3 with VMTS. Treatment: 0.2 ml of autologous plasmin intravitreally injected under topical anesthesia was administered to all patients. The plasmin was obtained by a simplified method with urokinase. Main outcome measures: Degree of detachment of the MEM and the VMTS measured by optical coherence tomography (OCT), and the best corrected visual acuity (Snellen scale) before and one month after the plasmin injection. The follow-up period was completed by all the patients. The MEM remained attached to the retina in all cases, as measured either by biomicroscopy or OCT. The VMTS was completely detached from the foveal area in all cases, with the disappearanc...
Ophthalmology, 2004
To study the effect of autologous plasmin enzyme (APE) on the adhesion of the vitreous cortex to the internal limiting membrane (ILM) in eyes with diabetic macular edema. Design: Nonrandomized, comparative, interventional case series. Participants: Ten eyes of 10 patients with diabetic macular edema without a posterior vitreous detachment (PVD), which were treated with APE as an adjunct to conventional pars plana vitrectomy, and 10 eyes of 9 patients without a PVD, which underwent pars plana vitrectomy without APE, were studied. Methods: In the APE group, 0.4 IU of APE was injected into the midvitreous cavity in 9 eyes, and 0.8 IU of APE in 1 eye. Thirty minutes after plasmin injection, the eyes underwent pars plana vitrectomy with ILM peeling. All eyes in the control group had conventional vitreous surgery with ILM peeling. The removed ILMs were investigated for the presence of vitreous and for ultrastructural differences by transmission and scanning electron microscopy. Main Outcome Measures: The status of the vitreous and induction of a PVD during surgery, and the presence of vitreous and ultrastructural differences of the removed ILM by transmission and scanning electron microscopy. Results: In APE-treated eyes, the degree of liquefaction of the vitreous was graded as high in 4 eyes. Spontaneous PVD occurred in 2 eyes, whereas core vitrectomy with a maximum vacuum of 100 mmHg induced a PVD in 2 additional eyes. In the control group, 8 eyes required suction with a maximum of 200 mmHg to induce the PVD. Scanning electron micrography of the removed ILM in the APE-treated eyes showed a smooth surface on the vitreous side in 8 eyes and only sparse collagen fibers in 2 eyes. Conversely, in the control group, dense vitreous fibers were found in 4 eyes, sparse collagen fibrils in 3 eyes, and a smooth retinal surface in 3 eyes. Conclusions: These findings indicate that APE helps separate the vitreous hyaloid from the ILM surface and may be a useful adjunct to conventional vitreous surgery for diabetic macular edema. Ophthalmology 2004;111: