Volume 39 ·  Issue 11 ·  2003

To Investigate the effectiveness and complications of injection of tissue plasminogen activator into a retinal vein for treatment of retinal vein occlusion via micropuncture of the retinal vein.

Thirty miniature pigs (one eye of each pig) were produced photodynamic thrombi of retinal vein by injecting Rose bengal (20 mg/kg) into the ear vein, and randomly divided into three groups: (1) control (n = 8), (2) infusion of sterile water (n = 8) or (3) infusion of tissue-type plasminogen activator (n = 14) in obstructed retinal vein. In the first group no micropuncture of retinal vein was performed. In the others micropuncture of retinal vein were performed by a micromanipulator that we designed and sterile water was infused in retinal vein in the second group or tissue-type plasminogen activator was infused in the third one. Fluorescent angiography and histological study were performed to document the morphological alterations with clinical observations.

18 eyes were successfully performed micropuncture of retinal vein in the 22 eyes (81.4%). Except stopping operation due to surgical accident, there were 7 eyes that the thrombi were lysed in 9 eyes by infusion of tissue-type plasminogen activator in obstructed retinal vein (77.8%). If the micropipette was not accurate for puncturing the vessels, the vessels' wall could be ruptured and hemorrhage appeared. If thrombi of retinal veins were lysed, no bleeding and no leakage of the infused drug were observed from the site of micropuncture after micropipette was withdrawn from the vessel. Sterile water failed to flush the clot downstream. When the thrombus failed to be dislodged, the infusion fluid would back flow into the distal retinal vein and, an exudative retinal detachment would occur. In the first group, the retina exhibited hemorrhages and edema due to the vein occluded. In the second group, sterile water resulted in exaggerated retinal edema and exudative retinal detachment. In the third group, after thrombi of retinal veins were lysed, the hemorrhages and edema of retinal tissues were reduced significantly in few days.

Infusing thrombolytic agents into the thrombosed retinal vein is a new method for treatment of retinal vein occlusion. This surgery must performed accurately by a special design. This study demonstrated that the rate and dose of thrombolytic agents infused in retinal vein should be limited in case of injuring retina tissues.

To explore the possible mechanism of ferulic acid(FA) on the proliferation of nerve cells of retinas in vitro and provide the principal for prevention and treatment of some degenerative retinal diseases.

Retinal cells suspension from 7 months human embryo, neonatal calf, and 4 months postnatal mice were treated with FA, brain-derived neurotrophic factor(BDNF) and kakonein were used as palcebo. 72 hours after incubation with BDNT, MTT and ³H-thymidine (³H-TdR) incorporation were used to evaluate cell proliferation and DNA synthesis.

The proliferation of three retinas cell lines was stimulated by the treatment of FA, it was shown that the effect of FA on cell viability was dose-dependent, and the highest response was seen in mice retinal cell. It has been found that to the adult mice group, FA within 15.6 to 1 000.0 mg/L was shown promotion for nerve cell proliferation, but only FA with 125.0-1 000.0 mg/L to that of 7 months human embryo, neonatal calf. To the 7 months human embryo group, FA with 62.5-1 000.0 mg/L was shown the promotion for DNA synthesis, moreover, 500.0 mg/L was most suitable for cell proliferation and DNA synthesis. BDNF with 12.5-50.0 μg/L was also shown promotion for nerve cell proliferation, moreover the 50.0 μg/L was the most suitable, but kakonein was not shown obvious promotional effect.

These results suggested that FA was better for nerve cell proliferation than that of BDNF, and would probably become one of new agents for prevention and treatment of some degenerative retinal diseases.

To assess the expression of bFGF, FGFR1, Bcl-2 and caspase-3 in human RPE cells exposed to visible light in vitro.

Cultured human RPE cells were exposed to visible light [(2 000 ± 500) Lux] for 12 hours. Immunocytochemical staining, enzyme-linked assays and RT-PCR were used to determine the expression of bFGF and its receptor FGFR1, Bcl-2 as well as the activity of caspase-3.

(1) Bcl-2 was detected in normal cultured human RPE cells. No significant change was found at 6 or 12 hours after light exposure (P> 0.05). But 24 hours after exposure, a significantly decreasing of Bcl-2 expression was observed (P< 0.01). The changes in expression of Bcl-2 mRNA paralleled to the changes in its protein, except that differences could be detected earlier viz. 12 hours after exposure. (2) The upregulation of bFGF and FGFR1 mRNA expression occurred with longer period of light exposure (P<0.05). (3) The upregulation of caspase-3 activity was detected 6 hours after light exposure, and was more significant over 6 hours and 12 hours (P< 0.05). No significant difference was found between 12 hours and 24 hours exposure (P> 0.05).

Visible light exposure over threshold causes upregulation of endogenous bFGF and FGFR1, downregulation of Bcl-2 and activation of caspase-3 in human RPE cells.

To investigate mRNA expression of vascular endothelial growth factor (VEGF) and its receptor FLK-1 in iris pigment epithelium (IPE) cells and retinal pigment epithelium (RPE) cells, and the feasibility of transplantation of autologous IPE cells to substitute RPE in the treatment of age-related macular degeneration (AKMD) and diseases of RPE dysfunction.

IPE and RPE cells were isolated from pigmented rabbits. The expression of mRNA for VEGF and FLK-1 were detected by reverse transcription polymerase chain reaction (RT-PCR).

Rabbit IPE and RPE cells express VEGF mRNA and FLK-1; the express of VEGF and FLK-1 mRNA in IPE cells was relatively low compared with the expression in RPE cells. The amount of VEGF mRNA in IPE cells was 44.62% of RPE cells, and amount of FLK-1 mRNA was 52.36% of RPE cells- The results of the differences of expression of VEGF and FLK-1 mRNA between IPE and RPE cells was statistically significant (t-test, P< 0.001).

VEGF and FLK-1 mRNA in IPE cells express is relatively low compared with the expression in RPE cells, and the results suggest that IPE cells could be more beneficial than RPE cells in the transplantation into the subretinal space.

To investigate the therapeutical effect of basic fibroblast growth factor (bFGF) on retina ischemia/reperfusion injury.

Experimental retinal ischemia/reperfusion injury was induced by increasing intraocular pressure of rats eyes. 48 rats were divided into groups of control, ischemia/reperfusion and bFGF-treated, randomly. Apoptotic cells were detected using the TdT-dUTP terminal nick-end labeling at 1 hour, 6 hours, 12 hours, 24 hours, and 72 hours after reperfusion. The expression of caspase-3 at specified times was determined by Streptavidin Peroxidase immunohistochemistry. Atomic absorption spectrum method was used to evaluate the intracellular calcium changes of retinal tissues.

In ischemia group, apoptotic cells began to appear at 6th hour after reperfusion and increased progressively with time. The number of apoptotic cells reached the peak 24 hour after reperfusion, and no apoptotic cells could be found at 72 hours. Changes in caspase-3 expression followed a similar trend. The intracellular calcium level of rat retina began to increase at 1 hour after reperfusion, and continued to increase with the reperfusion time. At 24 hours after reperfusion the intracellular calcium level reached the peak, and decline thereafter up to 72 hours. The patterns of change of the three markers of treatment group were similar to the above. However, the magnitude of changes was relatively lower. A statistically significant difference (P< 0.05) between the ischemia group and treatment group at 6th, 12th and 24th after reperfusion was observed.

Apoptosis may play a vital role in ischemia-reperfusion injury of the retina. bFGF may have a therapeutical effect on ischemia-reperfusion injury by inhibiting the increase of retinal intracellular calcium stores and caspase-3 protein expression.

To study the morphological features of submacular choroidal neovascularization in central exudative chorioretinopathy (CEC) using optical coherence tomography (OCT).

Using OCT, we examined 21 consecutive eyes (20 patients; 8 men, 12 women; mean age 38 years) with central exudative chorioretinopathy.

of OCT were compared with fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA).

Choroidal neovascularization appeared in subsensory retinal space anterior to the retinal pigment epithelium as a highly or moderately reflective mass, which protruded from the retinal pigment epithelium in 16 of 21 eyes. In five eyes, choroidal neovascularization appeared as a highly reflective fusiform or irregular mass at the level of retinal pigment epithelium and choriocapillaris. Nine of 21 eyes were associated with serous neurosensory retina detachment, 6 eyes with hemorrhagic pigment epithelium detachment (PED) and 14 eyes with edema and thickening of sensory retina. In 3 ~ 12 months (mean 6 months), choroidal neovascularization of 17 eyes with PDT regressed and its morphological features changed. The results obtained from OCT, FFA and ICGA could be supplemented with each other. Conclusions OCT can be used to confirm the morphological features, location and size of submacular choroidal neovascularization. Choroidal neovascularization appears as a highly or moderately reflective round mass which protrudes from the retinal pigment epithelium in most cases. The morphology and the size of this mass may change after treatment and during follow-up.

To study the clinical and imaging features together with diagnosis and management of orbital histocytosis X.

In a retrospective study from 1973 to 1999, 47 cases of histocytosis X were reviewed related with clinical materials, including eosinophilic granuloma 17 cases and Hand-Schuller-Christian disease 30 cases.

Most occur in children and teenagers, mainly in male. Characteristic clinical features, roentgenography, ultrasonography, CT, MRI provide the most diagnostic assistance.

Solitary unifocal eosinophilic granuloma mainly involves teenagers. Hand-Schuller-Christian disease usually take places between birth and 5 years of age, which is characterized by multifocal variant of eosinophilic granuloma, especially the classic triad. Characteristic images contribute to the diagnosis. Multiple management is needed, including surgery, chemotherapy and radiotheraphy. The prognosis varies with the three types.

To study the indication and incision of phacoemulsification and intraocular lens (IOL) implantation after high-risk penetrating keratoplasty (PKP) and to evaluate the clinical results.

Twenty-six eyes of 25 patients who underwent high-risk PKP were treated with phacoemulsification and IOL implantation. The high-risk reasons included chemical burn of cornea, severe infective corneal perforation, total keratoplasty, diameter of the corneal graft larger than 8.5 mm, secondary keratoplasty and PKP combined with cataract extraction and anterior segment vitrectomy. Systemic and local steroid administration was given and surgical indication and incision were chosen according to the condition of the eyes. The mean interval time between PKP and IOL implantation was 11 months. Visual acuity, refractive status, central corneal endothelial cell density before and after IOL implantation (3 months) and allograft rejection were recorded. The mean follow-up after IOL placement was 17 months.

Uncorrected visual acuity was 50/100 or better in 7 (27%) eyes and corrected visual acuity was 50/100 or better in 12 (46%) eyes. Fourteen (54%) eyes had refractive errors within 2 diopters. The mean refractive cylinders before and after IOL implantation were 5.70 D and 4.70 D, respectively (paired t test, t = 1.471, P=0.154). The endothelial cell density before and after IOL implantation was 1 883 cells/mm² and 1 760 cells/mm², respectively (t = 1.934, P = 0.065) and the rate of endothelial cell loss was 6.5%. Only one graft rejection (4%) occurred 7 months after IOL implantation (anterior chamber IOL).

It is safe and effective to perform phacoemulsification and IOL implantation after high-risk PKP when paying attention to the perioperative treatment and selecting the surgical indication and the position of the incision.

To study the surgical treatment of the subluxated lens with cataract caused by broken suspensory ligament of the lens.

Phacoemulsification combined with intraocular lens implantation was performed in 21 eyes. Extracapsular cataract extraction with small-incision was performed in 6 eyes. The visual acuity, the position of IOL, and the postoperative complications were observed and analyzed.

Postoperative vision was increased in all patients. Vision 3 days after the operation was 0.1-0.4 in 6 eyes and 0.5-0.8 in 21 eyes. Vision 1 month after the operation was 0.1-0.4 in 7 eyes and 0.5-0.8 in 20 eyes. The up-edge of IOL could be observed at normal pupil in only one eye. IOL positions were found to be diverged after dilation of the pupil in 2 eyes; no diplopia was experienced. There were no serious complications during or after the operation.

If the operator has perfect skill and chooses the optimal method, a good result can be obtained in surgical treatment of the subluxated lens.

To investigate patients who had ocular presentations after allogeneic hematopoietic stem cell transplantation.

The eyes of 20 patients of leukemia who had undergone allogeneic hematopoietic stem cell transplantation were examined. The ocular surface of these patients was examined by slit-lamp. The eye examination also included evaluation of tear break-up time, Schirmer tests with and without nasal stimulation, and fluorescein staining, rose bengal staining, etc. Conjunctival impression cytology and pathological examination of surgical specimens from 3 patients were performed.

Fourteen of 20 patients developed chronic graft-versus-host disease (cGVHD). Eight patients suffered from dry eye accompanied by GVHD simultaneously. The incidence of dry eye in GVHD was 57%. Among them, 4 cases were severe dry eye associated with significant decrease of visual acuity and even development of corneal ulcer. Ophthalmic pathology findings were as follows: loss of conjunctival goblet cells or significant reduction in amount; conjunctival and corneal epithelial keratinization and squamous metaplasia; and dominance of T cell in conjunctival inflammatory infiltration cells.

Dry eye is the major ocular complication after allogeneic hematopoietic stem cell transplantation. It affected the patients' life quality severely. The high incidence and potentially severe ocular problems in these patients suggest that close ophthalmic monitoring is important in allogeneic hematopoietic stem cell transplantation.