Alice J. Claflin

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.

Intravitreal Autotransplantation of Fibroblasts

Tissue cultured skin fibroblasts autotransplanted into the vitreous cavity of rabbit eyes formed intravitreal strands that grew toward the medullary ray and optic nerve head and caused preretinal puckers and traction detachment. After four weeks, 32 of 51 eyes (63%) developed these changes. Light and electron microscopy revealed initial cell death. Remaining cells aligned themselves quickly into strands and began to multiply as shown by tritiated thymidine methyl incorporation. The appearance of cells that resemble myofibroblasts may explain the contractability of the strand. Because the effect of intraocular proliferation can be quantitated by the number of puckers and retinal detachments developing, this model may be useful for the study of therapeutic means to reduce intraocular proliferation.

The effect of aqueous humor on the growth of subconjunctival fibroblasts in tissue culture and its implications for glaucoma surgery

We used aqueous humor from cataract patients and glaucoma patients as a medium for tissue culture of subconjunctival fibroblasts. The aqueous humor from cataract patients consistently inhibited the growth of their own subconjunctival fibroblasts, whereas that of some of the glaucoma patients did not. We found a significant correlation between the success of the filtering operation and the ability of that patients aqueous humor to inhibit the growth of fibroblasts in tissue culture.

Aqueous Humor Changes After Experimental Filtering Surgery

We studied aqueous humor of rhesus and owl monkeys for its effect on the growth of subconjunctival fibroblasts in tissue culture. Aqueous humor samples obtained before glaucoma surgery inhibited the initiation of growth of fibroblasts. However, postoperative aqueous humor samples supported growth of fibroblasts. The change in aqueous humor physiology lasted for up to two months after glaucoma surgery. Our study indicated that possibly material added to the postoperative aqueous humor inactivates an inhibitor normally present in primary aqueous humor. An alternative explanation would be that primary aqueous humor, in contrast to secondary aqueous humor, lacks sufficient nutrient material to support fibroblast growth in tissue culture.

Rapid induction of alkaline phosphatase activity by retinoic acid.

Abstract Retinoic acid (vitamin A acid) increased alkaline phosphatase activity in cultured cells derived from both normal rat prostate and the Dunning R-3327 transplantable prostatic adenocarcinoma. Retinoic acid was found to be 3–4-fold more effective as an inducer of enzyme activity than retinol or retinal. In one rapidly-growing cell line (UMS-1541Q) which has a barely-detectable level of enzyme activity in the uninduced state, increased activity could be detected as early as 3–4 hours after the addition of 10μM retinoic acid. This increase was totally blocked by actinomycin D and cycloheximide. The demonstrated rapid inducibility of alkaline phosphatase activity provides a specific marker for the action of retinoic acid at the molecular level.

Chemotherapy of the Transplantable Adenocarcinoma (R-3327) of the Copenhagen Rat

A number of therapeutic agents including L-asparaginase, Actinomycin-D, CCNU, Hydroxyurea, 5-FU, Cis-platinum, Cyclophosphamide, orchiectomy, Adriamycin and DES alone and in various combinations has been applied against the Dunning R-3327 rat prostatic adenocarcinoma subline G. We have found a parallel between the results of this study and those of similar therapeutic application to the human tumor. We conclude that this animal model may prove to be a useful screening system for agents against human prostatic cancer.

The Dunning R3327 prostate adenocarcinoma in the Fischer-Copenhagen F1 rat: A useful model for immunological studies

The Dunning R3327 tumor sublines in the Fischer-Copenhagen F1 rat provide a spectrum of transplantable prostate adenocarcinomas for the study of host-tumor interactions. The tumor can be transplanted with both fresh and cryopreserved cell suspensions. The F1 rat is an appropriate animal for immunological studies based on humoral and cellular immune responses. Preliminary evidence of the host-tumor relationship in the F1 rat indicates that purified membrane preparations induced a specific cytotoxic population of lymphocytes.

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.