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Biomedical subjects

A Ophir

Publications and source records attributed to A Ophir.

At least 37 records · Page 2Linked to original sources
PubMed1992

A possible role of free radicals in the transplantation of retinal pigment epithelial cells.

Oxygen-derived free radicals have been implicated in tissue injury following ischemia and reperfusion (reoxygenation). It has been hypothesized that the radicals are produced during the early reperfusion stage. Recently, submacular implantation of retinal pigment epithelium cells has been reported. It is probable that during the procedure, the transplant and the 180-degree folded outer retina underwent a period of ischemia, followed by reoxygenation. We, therefore, infer that free radicals were produced during the reoxygenation stage of the procedure, injuring both tissues. We suggest that these hypotheses be investigated with the aim of improving the surgical outcome in eyes with age-related macular degeneration.

Aging↗
PubMed1992

Trabeculectomy with 5-fluorouracil subsequent to circular buckling operation and cataract extraction.

Six patients, each with one eye that had previously undergone circular buckling surgery for the repair of retinal detachment before or followed by cataract extraction with or without intraocular lens implantation, underwent trabeculectomy with 5-fluorouracil (5-FU) for intractable glaucoma. Surgery was done through scarred subconjunctival tissues that were excised partially. The total doses of 5-FU ranged from 65 to 100mg (mean +/- standard deviation, 84.2 +/- 13.2mg) Eight to 47 months later, intraocular pressures were 18mmHg in five eyes, two of which were not receiving hypotensive medications. In the sixth eye, the intraocular pressure was 26mmHg with maximum hypotensive treatment. Intraocular pressures in the six eyes were significantly lower postoperatively than preoperatively (P < .05). This preliminary study suggests that filtering surgery with 5-FU may be beneficial after intraocular operations even in eyes where it is done through postoperative scarred subconjunctival tissues.

Adult↗
PubMed1992

Delayed filtering bleb encapsulation.

Encapsulated filtering blebs concomitant with increased intraocular pressure (IOP) developed 47 and 6 months, respectively, after surgery in two women, 46 and 60 years old, respectively, who had undergone trabeculectomy operations in one eye. Both blebs were associated with mild anterior uveitis. Following treatment with topical steroids, cyclopentolate, hypotensive medications, and digital massage, the uveitis resolved and the IOP fell. The likely cause of these late-appearing encapsulated blebs was anterior uveitis.

Epinephrine↗
PubMed1992

Encapsulated filtering bleb and subconjunctival 5-fluorouracil.

Filtering bleb encapsulation (BE) involves fibroblast proliferation and collagen synthesis. We analyzed the effect of 5-fluorouracil (5-FU) on the inhibition of BE. Forty-one patients with primary open-angle glaucoma underwent trabeculectomy in one eye as an initial surgery. Twenty-one of these eyes, randomly chosen, were treated postoperatively with four to six 5-FU subconjunctival injections over 10 days to inhibit bleb scarring; the remaining 20 eyes did not receive 5-FU. After 12 to 24 months, the surgical success rate was significantly higher in the treated eyes (P less than .05). However, the incidence of BE was similar: two eyes (9.5% and 10%, respectively) in each group. The difference between the effect of 5-FU in the inhibition of BE and bleb scarring suggests that the characteristics of the two fibroblast populations are heterogeneous.

Aged↗
PubMed1991

Effects of 5-fluorouracil on proliferating fibroblasts in vivo.

5-Fluorouracil (5-FU) is a potent inhibitor of the proliferation of fibroblasts, the main cell mediators of scar formation. The mechanism of the toxic effect of 5-FU on cancer cells is well known but unclear in nonmalignant cells. The histopathological effects of 5-FU on proliferating fibroblasts in vivo, 2 and 4 weeks after drug injection, are demonstrated here. An insertion of homologous fibroblasts into rabbits' vitreous followed by one injection of 1 mg 5-FU causes intracytoplasmic accumulation of vacuoles, morphological changes and inhibition of collagen deposition in the matrix.

Animals↗
PubMed1991

Further observations on the prevention of experimental proliferative vitreo-retinopathy by 5-fluorouracil.

The rate of retinal detachment in fellow control eyes of rabbits following fibroblast administration is progressively lower with increased dose of 5-Fluorouracil in the test eyes. Thus, it seems mandatory to choose control eyes in other animals rather than the fellow eyes of the treated ones. Retinal detachment appeared in the second week or earlier after intravitreal fibroblast administration. However, in eyes treated intravitreally with 5-Fluorouracil, retinal detachment or pucker appeared later, even in the second month suggesting routine follow-up of at least 2 months in future studies.

Animals↗
PubMed1991

Regulating the dose of 5-fluorouracil to prevent filtering bleb scarring.

Repeated doses of 5mg of 5-fluorouracil (5-FU) were injected subconjunctivally in 25 poor-prognosis glaucomatous eyes after filtering surgery to prevent filtering bleb scarring. The frequency (1-2 times a day) and duration (minimum, 7 days) of injections were determined by the degree of the anterior chamber reaction and/or conjunctival hyperemia at the filtering bleb site. Punctate corneal erosions or filaments were not considered a contraindication to continuation of 5-FU treatment. After 12 months, intraocular pressure (IOP) of 16 mmHg or less without medical treatment was found in 19 (76%) eyes. In 16 of these (64%), the IOP was 12 mmHg or less. In two (8%) other eyes, it was 20 mmHg or less with medication. We believe that the comparatively low IOP levels achieved without medical treatment in 76% of the eyes in our study can be attributed in part to our therapeutic approach with 5-FU.

Adolescent↗
PubMed1991

Subconjunctival 5-fluorouracil and herpes simplex keratitis.

We present a case of herpes simplex keratitis that appeared during a period following filtering surgery in which subconjunctival 5-FU was being administered. Although the 5-FU treatment was not halted, 4 days later the keratitis healed. The typical practice of discontinuing 5-FU treatment when these kinds of inflammation occur following filtering surgery may be unwarranted.

Eye Diseases↗
PubMed1990

[Prevention of scarring of filtering bleb by 5-fluorouracil].

Scarring of the filtering bleb is the most common cause of failure of surgery for glaucoma. It is much more common when the surgery is for certain types of glaucoma, such as aphakic glaucoma, cases of previously failed filtering surgery and neovascular and uveitic glaucoma. In 31 such high-risk cases we injected 5-fluorouracil subconjunctivally for 7-16 days after operation to prevent scarring of the filtering bleb. The success rate was 83%. After a follow-up of 3-12 months, there was statistically significant improvement in each group as compared to cases in which the drug was not administered. Further indications should be considered for the use of 5-fluorouracil in glaucoma.

Conjunctiva↗
PubMed1990

Filtering surgery with 5-fluorouracil: a second course.

In five glaucoma patients, a previous filtering surgery that was followed by sub-conjunctival injections of 5-Fluorouracil (5-FU) failed, due to filtering bleb scarring. A repetition of the filtering surgery with subsequent sub-conjunctival injections of 5 mg of 5-FU, administered once daily for 8-14 days, was undertaken. At the end of 6-19 months of follow-up, IOP levels in all five eyes were 20 mmHg or less with medication. A repeated course of filtering surgery plus 5-FU treatment seems to be a favourable surgical option in refractory glaucoma.

Adult↗
PubMed1984

5-fluorouracil: new applications in complicated retinal detachment for an established antimetabolite.

Long-term reattachment of the retina following the development of proliferative vitreoretinopathy is often prevented by the occurrence of cellular reproliferation. 5-fluorouracil, a synthetic pyrimidine analog, is a potent inhibitor of fibroblast proliferation in cell culture and an animal model of tractional retinal detachment. Doses of up to 1.0 mg, when administered intravitreally to rabbits, result in no demonstrable retinal toxicity by microscopic and electrophysiologic criteria. The first 22 consecutive patients with advanced forms of proliferative vitreoretinopathy were treated with a combination of periocular and intraocular 5-fluorouracil, in addition to scleral buckling and vitrectomy. Retinal reattachment was achieved in 60% of patients at 6 months postoperatively. No serious systemic or ocular complications were observed although delayed healing of corneal epithelial defects occurred in 18% of cases and subtle subepithelial scarring in 31.8%. In combination with standard vitrectomy techniques, post-operative fluid gas exchange, and photocoagulation, periocular and subconjunctival 5-fluorouracil appears to improve the prognosis for longterm retinal reattachment following the development of proliferative vitreoretinopathy.

Adolescent↗
PubMed1983

Prevention of experimental massive peri-retinal proliferation by 5-fluoro-uracil.

An intermediate report, on the effect of 1 mg 5-Fluoro-uracil on prevention of intra-vitreal fibroblast proliferation, strand formation and traction retinal detachment development in rabbits, is presented. The drug, which appeared to be nontoxic to the ocular tissues, prevented significantly the development of vitreous strands and traction retinal detachment in 10 out of 19 eyes (detachment rate, 47.3%), in comparison to 18 (control) eyes, out of 19, that did develop intravitreal strand and traction retinal detachment (94.7%).

Animals↗
PubMed1982

Experimental intraocular proliferation and neovascularization.

An experimental model of massive periretinal proliferation and intraocular neovascularization, produced in rabbits by the intravitreal injection of 250,00 cultured heterologous fibroblasts, showed no significant difference in the detachment rate (69% to 100%) or neovascularization rate (45% to 88%) between the animals injected with autologous cells and those injected with heterologous cells. Dermal fibroblasts produced a slightly higher detachment rate than conjunctival fibroblasts and were equally effective after reconstitution and subculture from liquid nitrogen storage in 7% dimethyl sulfoxide. Heterologous cells produced no clinical or histologic evidence of rejection when compared with autologous cells in the same animal and had the following advantages: (1) elimination of several biopsies and extended cell culture time; (2) a ready source of cryopreserved cells is available; (3) multiple injections of many animals can be performed within a short time; (4) in vivo and in vitro drug testing can be correlated on the same cell line.

Animals↗
PubMed1982

Fluorouracil for the treatment of massive periretinal proliferation.

A single intravitreal injection of fluorouracil was effective in the treatment of an experimental model of massive periretinal proliferation. When given with an intravitreal injection of 250,000 heterologous fibroblasts, fluorouracil decreased the rate of tractional retinal detachment from 36.8% in controls (seven of 19 eyes) to 5.2% in treated animals (one of 19 eyes) at one week, and from 73.6% in controls (14 of 19 eyes) to 31.5% in treated animals (six of 19 eyes) after four weeks (P less than .05). Intraocular neovascularization was reduced from 52.6% in controls (ten of 19 eyes) to 5.2% in treated animals (one of 19 eyes) after one week and 36.8% in controls (seven of 19 eyes) to 5.2% in treated animals (one of 19 eyes) after four weeks. When supplemented by repeated 10-mg subconjunctival injections of fluorouracil, or in combination with intravitreally administered indomethacin, this effect appeared to be enhanced. Intravitreal and subconjunctival injections of fluorouracil were well tolerated and may prove to be of significant value in the treatment of human disease.

Animals↗