Navaneet S.C. Borisuth

Detection, quantification, and significance of basic fibroblast growth factor in the aqueous humor of man, cat, dog and pig.

By using a highly specific and sensitive heterologous radioimmunoassay, we determined the content of basic fibroblast growth factor (bFGF) in fresh samples of aqueous humor obtained from human (n = 18), feline (n = 8), canine (n = 12), and porcine (n = 10) eyes by paracentesis. The content of bFGF in human aqueous humor ranged from 0.480 to 1.44 ng ml-1 (mean +/- S.D. = 1.074 +/- 0.297 ng ml-1); in feline samples, from 0.672 to 1.152 ng ml-1 (1.016 +/- 0.158 ng ml-1); in canine samples, from 0.640 to 1.232 ng ml-1 (1.026 +/- 0.171 ng ml-1); and in porcine samples, from 0.627 to 0.957 ng ml-1 (0.728 +/- 0.115 ng ml-1). These values were confirmed by means of a dot/slot-blot technique. For all species, the aqueous samples had normal protein levels that ranged from 5 to 19 mg dl-1. There was no correlation of the content of bFGF with the level of protein or with age of the human subjects. The similarity in the concentrations of bFGF in the aqueous humor as well as the stability of the blood-aqueous barriers of all four species indicate that cats, dogs, and pigs can serve as suitable animal models for the study of the role of bFGF in health and disease. We suggest the possible involvement of bFGF in the pathogenesis of anterior-segment disorders, such as neovascular glaucoma, and in the wound-healing response of limbal tissues after glaucoma filtration surgery.

Radioimmunoassay of epidermal growth factor in human lenses at various stages of development of cataract

By using a highly specific and sensitive homologous radioimmunoassay, we found that the content of epidermal growth factor (EGF) in the lateral one-third of whole cataractous human lenses (age range 45-85 yr) extracted at elective intracapsular lens surgery, varied from undetectable to 106.25 pg mg-1 water soluble protein (WSP) (mean +/- S.D. = 39.70 +/- 38.90). When the lenses were grouped according to the stage of the cataract, i.e. immature (n = 3), mature (n = 4), and hypermature (n = 3), the means +/- S.D. were 92.56 +/- 26.23, 23.89 +/- 7.71, and 7.92 +/- 2.00 pg mg-1 WSP, respectively. In ten age-matched whole normal lenses that we removed within 2-12 hr after death, the values in EGF of the lateral one-third of the lenses ranged from 2.91 to 36.40 pg mg-1 WSP (19.39 +/- 13.65). No correlation between the age of the lenses and the content of EGF could be demonstrated at the 95% confidence interval for the cataractous and normal lenses. The quantity of endogenous EGF correlated significantly (P less than 0.01) with the clinical stage of the cataract and is probably related to the mitotic activity of the equatorial proliferative zone. We discuss the importance of EGF in normal and cataractous lenses and postulate that EGF in the lens is endogenous in origin.

Mapping of Fc gamma receptors in the human and porcine eye.

By using an immunohistochemical technique, we detected a strong reaction product for Fc gamma receptors in the keratoconjunctival epithelium, uveal trabecular meshwork, optic nerve, and muscle walls of the retinal and ciliary vessels of infant human eyes; moderate staining was seen on the corneal endothelium, corneoscleral trabecular meshwork, non-pigmented ciliary epithelium, ciliary muscle fibers, endothelial lining of ocular blood vessels, as well as the anterior region of Muller cells, the outer nuclear layer, and pigment epithelium of the retina. In aged human and porcine eyes, the same structures stained somewhat less intensely than did those in infant human tissues. Primary cultures of porcine trabecular cells demonstrated a more intense immunoreaction product than did tertiary cultures. We discuss the possible role of Fc gamma receptors in various ocular inflammatory conditions and the implications of age-dependent expression by human trabecular cells in the pathogenesis of open-angle glaucoma.