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At least 325 records · Page 18Linked to original sources
PubMed1992

The effect of trabeculectomy on corneal topography.

Trabeculectomy is increasingly being performed earlier in the treatment of primary open-angle glaucoma (POAG). Surgically-induced alterations in corneal curvature resulting from filtering surgery may have a significant impact on patients, especially younger ones, whose vision may already be compromised by visual-field loss. Using data obtained by computer-assisted topographic analysis performed preoperatively and at 12 weeks postoperatively, we longitudinally studied the corneal surface changes induced by primary trabeculectomy in eight eyes undergoing surgery for POAG or normal-tension glaucoma. Additional data collected included refraction, keratometry, axial length, intraocular pressure, and pachometry. Five of eight eyes developed 1.50 to 2.50 diopters of steepening in the 90-degree meridian. One patient developed flattening in the 180-degree meridian without vertical steepening. Two patients had little change in the central optical zone. Of the six eyes with induced with-the-rule astigmatism, keratometry was less sensitive than topographic analysis in detecting the changes induced by trabeculectomy. Our data indicate that changes in corneal curvature are induced by filtering surgery, but may be undetectable without topographic analysis.

Astigmatism↗
PubMed1991

Interferon-gamma inhibits collagen synthesis by human Tenon's capsule fibroblasts in vitro.

Collagen deposition is largely responsible for scar information, an undesirable outcome of glaucoma filtering surgery. Because interferon-gamma (IFN-gamma) has been reported to inhibit collagen synthesis in a variety of cells, the authors examined its effect on collagen synthesis by Tenon's capsule fibroblasts cultured from three patients. In addition, the authors studied the effects of IFN-gamma on fibroblast proliferation. IFN-gamma inhibited collagen synthesis at dosages of 1-10,000 U/ml. The average median effective dose (ED50) was 6.60 U/ml. In contrast, IFN-gamma had no significant effect on cell proliferation in dosages of 0.001-10,000 U/ml. These results suggest that IFN-gamma may be a useful agent for modifying the wound healing response, particularly after glaucoma filtering surgery.

Adult↗
PubMed1993

Incidence of complications following 5-fluorouracil with trabeculectomies.

To investigate the incidence of complications reportedly caused by the use of 5-fluorouracil (5-FU) in glaucoma filtering surgery, we performed trabeculectomy with 5-FU on 57 eyes of 56 patients with advanced glaucoma. The mean preoperative intraocular pressure was 34.8 mm Hg. The most frequent complication encountered was superficial punctate keratopathy (26%), followed by shallowing of the anterior chamber (12%), choroidal detachment (9%), and flap retraction (7%). We, however, did not encounter any cases of confluent corneal epithelial defect, subepithelial scarring, or striate melanokeratosis which are usually described with the use of 5-FU. With a mean follow-up of 7.1 months, an intraocular pressure less than 16 mm Hg without hypotensive therapy were achieved in 73.7% of cases, and less than 21 mm Hg without hypotensive therapy in 86%. Considering the low incidence of complications and the high success rate, we recommend the use of 5-FU in routine glaucoma filtering surgery.

Combined Modality Therapy↗
PubMed1987

The effect of beta irradiation on monkey Tenon's capsule fibroblasts in tissue culture.

Fibroblast proliferation with subsequent bleb scarring is a major cause of filtering surgery failure. To investigate possible antiproliferative effects of beta radiation, owl monkey Tenon's capsule fibroblasts in tissue culture were irradiated to doses of 30, 100, 300, 1,000, and 3,000 rads with a linear accelerator and to doses of 95,285, and 950 rads with a Strontium-90 applicator. The irradiated cell proliferation expressed as the percentage of the non-irradiated control growth on the third and seventh days, respectively, after beta irradiation was: 97% and 96% after 30 rads; 72% and 90% after 100 rads; 48% and 44% after 300 rads; 39% and 14% after 1,000 rads; and 39% and 14% after 3,000 rads. Similar effects on cell proliferation were observed with the Strontium-90 applicator. The inhibitory effect of beta irradiation on fibroblast proliferation in tissue culture suggests that beta irradiation after filtering surgery may reduce postoperative bleb scarring.

Animals↗
PubMed2000

Outcome of trabeculectomy with mitomycin-C in the iridocorneal endothelial syndrome.

PURPOSE: Eyes with iridocorneal endothelial (ICE) syndrome have a high risk of failure in glaucoma filtering surgery failing. We investigated the efficacy of trabeculectomy with intraoperative mitomycin-C application in these patients. DESIGN: Retrospective nonrandomized comparative trial with historical controls. PARTICIPANTS AND CONTROLS: Ten patients with unilateral iridocorneal endothelial (ICE) syndrome were reviewed. Their intraocular pressures could not be controlled medically. In five eyes, this was the primary surgery performed. Five of the patients had undergone prior intraocular pressure-(IOP) lowering surgery that had failed at the time enrolled. Results were compared with previously published case series of similar patients treated with trabeculectomy alone or trabeculectomy and subconjunctival 5-fluorouracil injections. INTERVENTION: Intervention consisted of trabeculectomy with a limbus-based conjunctival flap and mitomycin-C application. The dosage of mitomycin-C was 0.4 mg/ml for 1 to 4 minutes (mean, 1.9 min). MAIN OUTCOME MEASURES: Adequate control of IOP (without medication lower than 21 mm Hg). RESULTS: In eight eyes the IOP remained well controlled (mean IOP, 12.1 mm Hg) over the entire length of available of follow-up (mean, 14.9 months). Two eyes required implantation of an aqueous tube shunt at 4 and 11 months, respectively, after trabeculectomy with mitomycin-C. One eye experienced visual loss of 3 Snellen lines because of hypotony maculopathy. CONCLUSIONS: Trabeculectomy with mitomycin-C application offers a reasonable intermediate-term success rate in ICE patients, who are otherwise at high risk for failure of filtering surgery.

Adult↗
PubMed1996

A novel MMC-loaded pHEMA drainage device for the treatment of glaucoma: in vitro and in vivo studies.

Administration of subconjunctival 5-fluorouracil (5-FU) and topical mitomycin-C (MMC) has been shown to improve the success rate of glaucoma-filtering surgery. However, corneal toxicity and administrative problems remain. To overcome this limitation, drainage devices for the sustained release of 5-FU and MMC were designed and tested in vitro and in vivo. This paper presents only the results of our studies which were carried out on MMC-loaded devices. Here, the drainage devices were prepared from MMC-loaded poly(hydroxyethyl methacrylate) (pHEMA) matrices in different cross-linking ratios and in different drug loading capacities, i.e. 0.2, 0.5, and 2.0 mg MMC per device. These devices released MMC at approximately 6.0-90.0 micrograms day-1 for over 2 months depending on cross-linking density and initial drug loading. The diffusional release of MMC from glassy and swollen copolymers showed that diffusion mechanism is Fickian in both cases. The usability of the pHEMA implants were investigated by in vivo experiments which were done on eight dog's eye. In the treatment eyes, intraocular pressures remained significantly lower than the control eyes throughout the experimental period (4 months). Subconjunctival implantations revealed no clinical and histological evidence for toxicity. The results of in vitro and in vivo studies indicate that an implantable release system delivering MMC for over 2 months can improve the prognosis for filtering surgery by preventing postoperative fibrosis.

Administration, Topical↗
PubMed1997

In vitro effects of doxorubicin and mitomycin C on human Tenon's capsule fibroblasts.

Doxorubicin is an antiproliferative agent, that also inhibits prolyl 4-hydroxylase in vitro. We evaluated the effects of doxorubicin and mitomycin C (MMC) on the proliferation of human Tenon's capsule fibroblasts and the secretion of type I collagen in these cells to explore the potential use of doxorubicin as an antifibrotic agent after glaucoma filtering surgery. Standard immunoassays were used to determine the concentrations of type I procollagen COOH-terminal peptide (PIP), laminin and vitronectin receptor in conditioned media and cell lysates in the presence or absence of doxorubicin or MMC. The mitotic activity and viability of these cells were also determined. Cellular ultrastructure was evaluated by transmission electron microscopy. Doxorubicin and MMC decreased the cellular viability, the mitotic activity, and the production of the peptides measured. The inhibition of PIP secretion into the culture medium was higher in doxorubicin-treated cultures than in MMC-treated cultures at the tested concentrations (5-100 microM). The decrease in PIP levels in cell lysates was less in doxorubicin-treated culture (25 microM) than in MMC-treated culture (25 microM), suggesting that procollagen synthesis and secretion might be attenuated by doxorubicin. Ultrastructural studies revealed increased numbers of lysosomes in the cytoplasm of doxorubicin-treated cells relative to MMC-treated cells. Doxorubicin and MMC reduced cell viability and inhibited the proliferation and synthesis of PIP, laminin, and vitronectin receptor peptide. Inhibitory effects of doxorubicin on PIP secretion were more potent than those of MMC. Doxorubicin may be useful for inhibiting the fibrotic response at the site of ocular filtering surgery.

Adult↗
PubMed1994

Transcriptional control of human Tenon's capsule fibroblast collagen synthesis in vitro by gamma-interferon.

PURPOSE: Gamma-interferon (gamma-IFN) has been shown to be a potent inhibitor of collagenous protein production independent of its effects on noncollagenous protein production and cell proliferation in vitro. To understand further the processes controlling tissue fibrosis and the potential use of gamma-IFN as an antifibrotic treatment after glaucoma filtering surgery, the in vitro effects of recombinant gamma-IFN on procollagen mRNA production were studied. METHODS: Subconfluent human Tenon's capsule fibroblast cultures were exposed to 10, 50, 500, and 1000 U/ml of human recombinant gamma-IFN for 48 hours and to 500 U/ml for 12, 24, and 72 hours. After the incubation period, polyA+ mRNAs were isolated by oligo (dT) cellulose columns, separated according to size by electrophoresis through a denaturing agarose gel, and transferred to an activated nylon membrane for Northern blot analysis. The levels of type III (alpha 1) procollagen, type I (alpha 1) procollagen, and fibronectin (noncollagenous protein) mRNA were determined by hybridization with radiolabeled cDNA probes specific for these components followed by autoradiography. RESULTS: Densitometric analysis showed gamma-IFN selectively inhibited type III and type I procollagen mRNA synthesis from 24% (10 U/ml) to 99% (1000 U/ml) while leaving fibronectin mRNA synthesis unaffected. The degree of inhibition was also time dependent; more inhibition occurred with increasing incubation time. CONCLUSIONS: These results indicate that gamma-IFN is able to regulate collagen synthesis at the transcriptional level and that its inhibition is relatively specific. Gamma-interferon's specific inhibitory effects may offer advantages over current therapies in modulating the fibrotic response after glaucoma filtering surgery.

Cell Line↗
PubMed2002

Antiproliferative effect of mycophenolate mofetil on cultured human Tenon fibroblasts.

BACKGROUND: Wound healing after glaucoma filtering surgery is often complicated by exaggerated scarring of the subconjunctival Tenon's layer. Therefore, antiproliferatives are commonly employed. The immunosuppressive drug mycophenolate mofetil (MMF) is used to prevent graft rejection after kidney or liver transplantation. The effect is mediated by inhibition of lymphocyte proliferation. In this study we investigated the effect of MMF on human Tenon fibroblast proliferation in cell culture. METHODS: Human Tenon fibroblasts (HTF) were cultivated with 10% fetal calf serum. Cells were incubated with MMF concentrations of 0.1 microM to 3000 microM for up to 20 days. In a second set of experiments HTF were incubated for 10 min only in MMF solutions. Cell counts were performed to evaluate the proliferation rate. The proliferation was also assessed by Ki67 staining. Morphological changes were documented by vimentin staining. RESULTS: Growth inhibition of HTF by MMF was concentration dependent. IC(50) was 0.85+/-0.05 microM for 6 days of incubation. Brief exposure to MMF leads to a reversible growth arrest for up to 14 days with concentrations of 1000 microM or higher. Ki67 staining confirmed the concentration dependent proliferation rate. CONCLUSION: MMF has a concentration-dependent antiproliferative effect on HTF without any detected cytotoxicity in the applied concentration range. Brief incubation also leads to a growth arrest; therefore, intraoperative MMF application might prevent exaggerated scarring after glaucoma filtering surgery.

Aged↗
PubMed1996

Immunolocalization of prolyl 4-hydroxylase in fibroblasts cultured from Tenon's capsule of humans.

BACKGROUND: The excessive accumulation of extracellular matrix (ECM) with the repopulation of fibroblasts may lead to an unsuccessful outcome of glaucoma filtering surgery. We examined the immunolocalization of ECM components and prolyl 4-hydroxylase, an enzyme involved in collagen biosynthesis, in cultured Tenon's capsule fibroblasts (TCFs) of humans to evaluate the production of ECM in the cells. METHODS: We used light microscopy to evaluate the immunolocalization of prolyl 4-hydroxylase and ECM components, collagen types I, III, and IV, cellular fibronectin, and laminin in TCFs. Ultrastructural localization of the enzyme was also evaluated by electron microscopy. RESULTS: Immunoreactivity with monoclonal antibodies against the alpha and beta subunits of the enzyme or with the polyclonal antibody against it was detected in the cytoplasm of the cells in a fine granular pattern, indicating its localization in the endoplasmic reticulum (ER). Immunoreactivity for the enzyme was detected in the cisternae of the ER on electron microscopy. Types I and III collagen reactivities were also observed in the cytoplasm in a fine granular pattern. Type IV collagen reactivity was present diffusely on the cell surface. The distribution of laminin reactivity in the cytoplasm resembled that of types I and III collagen. Cellular fibronectin reactivity was observed in the ECM in a reticular pattern. CONCLUSION: Prolyl 4-hydroxylase was located in the cisternae of the ER. TCFs produced a variety of ECM components in vitro. The results provide insight into the fibrotic process during scar formation at the site of a bleb following filtering surgery.

Aged↗
PubMed1999

An experimental study on homoharringtonine liposome and glaucoma filtration surgery.

PURPOSE: To observe the inhibitory action of homoharringtonine liposome during the healing process of wounds in the filtering sites. METHODS: Posterior sclerectomies were performed in 14 rabbits. Postoperatively one eye of each rabbit received subconjunctival injections of HH liposome and fellow eye received saline injection in a randomized masked fashion. RESULTS: Fourteen days after operation the IOP of experimental eyes reduced significantly (P < 0.01) as compared with the controlled eyes, and the number of remaining filtering blebs increased noticeably (P < 0.05). Pathohistological examination revealed that the number of fibroblasts per square micron in the filtering sites and the thickness of the scars in the center of the filtering sites of the experimental eyes were less than those of the controlled eyes. No serious ocular toxic and side effects were found. CONCLUSION: This experiment suggest that homoharringtonine liposome can markedly inhibit the scar formation of filtering sites after glaucoma filtering surgery, promote the formation of filtering blebs, and provide an experimental evidence for its clinical use in future.

Animals↗
PubMed2006

Trabeculectomy and phacotrabeculectomy, with mitomycin-C, show similar two-year target IOP outcomes.

BACKGROUND: To determine the efficacy and safety of trabeculectomy with mitomycin-C (trabMMC) compared with that of single-site phacotrabeculectomy with mitomycin-C (phacotrabMMC) in glaucoma patients at increased risk for filtering surgery failure. METHODS: Eighty-five consecutive eyes that underwent trabMMC and 105 consecutive eyes that underwent phacotrabMMC were retrospectively compared up to 2 years postoperatively with respect to intraocular pressure (IOP), number of glaucoma medications, and surgical complication rates. The primary outcome was the difference in the cumulative proportion of patients meeting the target IOP range at 2 years. Secondary outcomes included mean postoperative IOP, mean IOP drop from baseline, mean number of glaucoma medications, and surgical complication rates. RESULTS: Baseline characteristics were similar in the 2 groups and most patients had advanced glaucoma with a similar upper limit of the target IOP range (15.5 +/- 2.6 mm Hg for trabMMC vs. 15.3 +/- 2.1 mm Hg for phacotrabMMC, p = 0.56). Loss to follow-up was significant in both groups (almost 50% over 2 years). A statistically similar proportion of patients achieved their target IOP range at 1 and 2 years in both groups: the cumulative success rate at 2 years was 29.04% and 22.91% (p = 0.44) without add-on glaucoma therapy, 25.38% and 25.22% (p = 0.60) with the use of up to 2 glaucoma medications, and 30.01% and 25.17% (p = 0.81) with the use of any number of glaucoma medications, in the trabMMC and phacotrabMMC groups, respectively. Mean postoperative IOP was also similar between the 2 groups at almost all follow-up times up to 2 years (13.56 +/- 4.92 mm Hg in trabMMC vs. 13.98 +/- 4.74 mm Hg in phacotrabMMC at 2 years, p = 0.67). The mean IOP drop from baseline was significantly greater in the trabMMC group throughout the study period (-10.87 +/- 8.33 mm Hg in trabMMC vs. -6.15 +/- 7.01 mm Hg in phacotrabMMC at 2 years, p = 0.003); however, baseline IOP was also higher in the trabMMC group (26.1 mm Hg vs. 20.3 mm Hg, p < 0.0001). Serious postoperative complication rates were similarly low between the 2 groups. INTERPRETATION: TrabMMC and phacotrabMMC may be equally safe and effective in bringing IOP to within an acceptable target range over 2 years in advanced glaucoma patients at increased risk for filtering surgery failure, although trabMMC appears to be associated with greater IOP lowering from baseline.

Adult↗
PubMed1994

Modulation of human fibroblast activity by selected angiogenesis inhibitors.

Tenon's fibroblast (TF) bleb encapsulation is a common cause of filtering surgery failure. Various pharmacologic agents have been used in an attempt to inhibit this response. The effects of three angiogenesis inhibitors were studied. AGM-1470, a fumagillin analog and hydrocortisone 21-phosphate (HC21P) complexed with heparin or with the heparin analog beta-cyclodextrin tetradecasulfate (BCD-TDS) in modulating human tenon's fibroblasts in cell culture. It has been clinically demonstrated that well vascularized blebs are associated with a poorer prognosis. In addition to reducing bleb neovascularization, angiogenesis inhibitors may have an additional therapeutic role in decreasing fibroblast activity. Drug effects were assessed by studying cell growth rates by cell Coulter counting and rate of wound closure. TF's were grown in DMEM with 10% FBS and 1% PCN-strep with fungizone. Angiogenesis inhibitors were added to growth medium in varying concentrations: AGM-1470 alone, HC21P complexed with heparin and HC21P complexed with BCD-TDS. Controls were grown in control medium alone, medium with added ethanol, or with added BCD-TDS, heparin or HC21P. We found a dose related inhibition of cell growth with all of the angiogenesis inhibitor combinations, which was not seen in the control groups. Tenon's fibroblast proliferation was significantly inhibited by AGM-1470 as seen in the four higher concentrations (P < 0.05) with insignificant inhibition at the lowest concentration of AGM-1470 (P = 0.38). The heparin:HC21P and heparin:BCD-TDS combinations demonstrated significant inhibition at all concentrations (P < 0.05). Wound closure was significantly inhibited by all the added agents, except AGM-1470 and the controls. The rate of wound closure was significantly reduced by the highest concentrations of the heparin:HC21P and heparin:BCD-TDS combinations (P < 0.05), although it was not significantly affected by lower concentrations (P > 0.05). Rank order of potencies of these agents for inhibition of TF proliferation was AGM-1470, BCD-TDS:HC21P, heparin:HC21P, HC21P, while the rank order of potencies for these agents for inhibition of wound closure was HC21P, heparin:HC21P, BCD-TDS:HC21P, AGM-1470. These selected angiogenesis inhibitors appear to have marked inhibitory effects on TF proliferation and migration, which may have a potential clinical role in modulating wound healing associated with glaucoma filtering surgery.

Cell Division↗
PubMed2006

Mitomycin: clinical applications in ophthalmic practice.

Mitomycin (mitomycin C; MMC) is an antibiotic isolated from Streptomyces caespitosus. The drug is a bioreductive alkylating agent that undergoes metabolic reductive activation, and has various oxygen tension-dependent cytotoxic effects on cells, including the cross-linking of DNA. It is widely used systemically for the treatment of malignancies, and has gained popularity as topical adjunctive therapy in ocular and adnexal surgery over the past 2 decades. In ophthalmic medicine, it is principally used to inhibit the wound healing response and reduce scarring of surgically fashioned ostia. Hence, it has been used as adjunctive therapy in various ocular surgeries, such as glaucoma filtering surgeries, dacryocystorhinostomy, corneal refractive surgery and surgeries for ocular cicatrisation. In addition, it has been used as an adjunct in the surgical management of pterygia, ocular surface squamous neoplasia, primary acquired melanosis with atypia and conjunctival melanoma. In many of these surgeries and ophthalmic pathologies, MMC showed a significant beneficial effect.

Antibiotics, Antineoplastic↗
PubMed2005

Outcome of cataract extraction and posterior chamber intraocular lens implantation following glaucoma filtration surgery.

PURPOSE: To evaluate the outcome of cataract extraction (CE) after glaucoma filtering surgery (GFS). METHODS: A total of 77 eyes (77 patients) who underwent CE with posterior chamber intraocular lens (PCIOL) implantation following GFS by a single surgeon were reviewed. Main outcome measures were preoperative and postoperative intraocular pressures (IOPs), visual acuities, medications, astigmatism, bleb survival, time of surgical failure, complications, and success rate. RESULTS: Mean time interval between GFS and CE was 46.8+/-50.9 months (range, 2-348 months). The mean preoperative IOP was 13.9+/-4.7 mmHg (range 3-27 mmHg) and mean postoperative IOP at 3 weeks was 13.6+/-5.5 mmHg (range, 6-44 mmHg). The mean follow-up was 19.5+/-20.1 months (range, 1.4-73 months; median 10.6 months). Complete success was achieved in 59 eyes (76.7%). The cumulative probability of complete success was 91.3+/-3.7, 82.0+/-5.6 and 78.1+/-6.5% at the end of 6 months, 1, and 2 years, respectively. Visual acuity before CE was < or =20/50 in all eyes (100%). Visual acuity at last visit was > or =20/40 in 33 eyes (42.8 %), 20/50-20/80 in 30 eyes (39.0%), < or =20/100 in 14 eyes (18.2%). Risk factors identified for qualified success included age at CE>60 years, interval of < or =5 months between GFS and CE, use of preoperative glaucoma medications, and postoperative IOP >19 mmHg within 2 weeks. CONCLUSIONS: IOP and bleb function was maintained after CE with PCIOL implantation following successful GFS with good visual recovery.

Adult↗