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Biomedical subjects

A Hajek

Publications and source records attributed to A Hajek.

7 recordsLinked to original sources
PubMed1988

Fluorouracil therapy of intraocular Greene melanoma in the rabbit.

We evaluated the efficacy of intraocular and periocular fluorouracil treatment in an experimental iris tumor of the rabbit (Greene amelanotic melanoma). Four consecutive intravitreal injections of 1 mg of fluorouracil given twice weekly completely suppressed tumor growth in all treated eyes for six weeks if treatment was initiated 24 hours after tumor implantation. In contrast, all control eyes implanted with an equal number of Greene melanoma cells but treated with intravitreal saline developed massive tumor invasion of the iris within two weeks. Additional subconjunctival therapy following intravitreal therapy for two weeks was only slightly more effective than intravitreal therapy alone. If therapy was delayed for one week, the iris tumors became macroscopically visible and subsequent treatment with intravitreal and subconjunctival fluorouracil was of limited value in suppressing growth.

Animals↗
PubMed1987

Mutagenic potential of a 193-nm excimer laser on fibroblasts in tissue culture.

In response to concerns regarding possible DNA damage by far ultraviolet radiation during excimer laser corneal surgery, the mutagenic potential of an argon fluoride excimer laser (193 nm) on BALB/3T3 mouse fibroblasts grown in tissue culture was investigated. The cumulative incidence of anaplastic transformation after subablative radiant exposures from 3.5 mJ/cm2/pulse to 13.4 mJ/cm2/pulse was 3.6% of all cell cultures. The incidence of anaplastic transformation in nonirradiated controls was 4.2%. Transformation after exposure to x-ray radiation (60.9 rad) was 98.8%. The difference between the incidence of transformation of nonirradiated controls or excimer-treated cultures compared with x-ray radiation-treated cells was significant P less than 0.0001 (chi square test). In this standard cell line, 193-nm laser energy does not appear to have substantial mutagenic potential.

Anaplasia↗
PubMed1985

Cellular sensitivity to glucocorticoids in patients with POAG. Steroid receptors and responses in cultured skin fibroblasts.

The question of a generalized hypersensitivity to corticosteroids in primary open-angle glaucoma (POAG) was investigated using cultured skin fibroblasts from patients with POAG and age-matched controls. Nuclear binding of (3H)-dexamethasone was performed to evaluate possible changes in the glucocorticoid receptors. Cortisol effects on (3H)-thymidine uptake into the cells were investigated as a measure of the cellular sensitivity to corticosteroids. When POAG and control groups were compared, no significant differences (P less than 0.05) were found for either the number or affinity of glucocorticoid receptors (POAG: Kd = 6.1 +/- 1.0 nM, Rt = 94 +/- 13 sites/cell X 10(3); control: Kd = 5.5 +/- 1.6 nM, Rt = 124 +/- 20 X 10(3) sites/cell) or for cortisol effects on thymidine uptake (POAG: C50 = 83 +/- 38 nM; control: C50 = 80 +/- 34 nM). Use of epidermal growth factor (EGF) resulted in an increased steroid sensitivity in some cell lines, but again no differences between POAG and control groups were detected. These results suggest that a generalized cellular hypersensitivity to glucocorticoids is not intrinsic to POAG. It is possible that environmental alterations and/or endogenous factors may influence the steroid responses observed in these patients.

Adult↗
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↗