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Protein Metabolism in the Rabbit Cornea
SOCIETY PROCEEDINGS 6th, 9th, 12th, 16th and 21st days. The anterior portion of each eye was studied histologically. An intense inflammatory reaction was found in the cornea from Days 1 to 6. No tumor cells were identified in the cornea but some were found in the anterior chamber. From Days 6 to 8, the tumor was noted in the cornea. Beyond Day 9, the growth of the tumor was so extensive it was impos sible to determine its anatomic origin. SPECIFIC
SUBSTANCES
IN
LENS
DEVELOP
M E N T AND LENS REGENERATION DRS. D. J. MCCALLION, P. M. LENICQUE, R. P. THOMPSON AND I. N I A Z E : Localiza
tion of specific substances: Alpha, beta, gamma crystalline were identified by using antilens sera from rabbits which had been injected with lens homogenate from chicken eyes. Fluorescent labelling determined the site of distribution of the crystalline. Alpha crystallin was present in the pri mary optic vesicle and wall of the brain. It then concentrated in the lens placode and ultimately in lens, disappearing elsewhere. Beta crystallin appeared later, when poste rior lens fibers were distinguishable, in the posterior part of lens. Gamma crystallin ap peared even later, no exact distribution was determined. The casual relationship between alpha crystallin and lens formation was not appar ent but a whole eye extract tended to inhibit differentiation of lens and nervous retina, when the lens extract was fractionated the fraction containing nucleotides inhibited lens differentiation, the margin of optic cup was a source of lens regeneration. If the optic vesicle was explanted 72 hours, 70 percent did develop a small lenticle from the margin of optic cup. A few hours later, alpha crystallin had disappeared from cup, such regeneration did not occur. It was suggested that alpha crystallin is a factor in early states of lens formation and that beta crystallin is involved in the forma
837
tion of fibers from the posterior pole at a later stage. PROTEIN METABOLISM I N T H E RABBIT COR NEA DR. R. C. FRENCH AND M R S . Z. D U M A :
Proteins make up over 80 percent of dry weight of the cornea. Labelled amino acids were injected into the anterior chamber, and their incorporation into the cornea of the rabbit was studied. C1* was used to label glycine and proline for this purpose, since these two amino acids form 50 percent of the amino-acid residue of the corneal pro tein. Rabbit stromal cells in tissue culture are found actively to incorporate the (^"-la belled glycine and proline. Heat-killed cells showed comparatively little activity. Amino-acid uptake, as shown by C14 up take of the endothelium, was twice as ac tive, and the epithelium four times as active, as that of the stroma. Uptake into the cornea from the anterior chamber was considered to be an active metabolic synthesis, rather than adsorption. This synthesis is inhibited by chlorampheni col in high concentrations. SILICONE 200 AND PHOTOCOAGULATION DRS.
W.
G.
ROMBOUGH
AND C.
B.
A method of replacing vitreous humor of rabbits with silicone 200, having a viscosity of 1,000 centistokes, was de scribed. The conjunctiva is incised five mm. behind the limbus and a silk suture is placed in the sciera. A radial two-mm. incision is made through the sciera and choroid and vitreous humor, 0.5 cc, is removed through a No. 18 blunt needle connected to a syringe. Using a new needle and syringe, 0.5 cc. of silicone 200 is then injected into the vitreous cavity. The preplaced suture is tightly drawn before removing the needle. Once the silicone was injected, it lay in the upper part of the vitreous cavity. Photo coagulation using a setting of GI06 was MORTIMER:
SUBSTANCES
IN
LENS
DEVELOP
M E N T AND LENS REGENERATION DRS. D. J. MCCALLION, P. M. LENICQUE, R. P. THOMPSON AND I. N I A Z E : Localiza
tion of specific substances: Alpha, beta, gamma crystalline were identified by using antilens sera from rabbits which had been injected with lens homogenate from chicken eyes. Fluorescent labelling determined the site of distribution of the crystalline. Alpha crystallin was present in the pri mary optic vesicle and wall of the brain. It then concentrated in the lens placode and ultimately in lens, disappearing elsewhere. Beta crystallin appeared later, when poste rior lens fibers were distinguishable, in the posterior part of lens. Gamma crystallin ap peared even later, no exact distribution was determined. The casual relationship between alpha crystallin and lens formation was not appar ent but a whole eye extract tended to inhibit differentiation of lens and nervous retina, when the lens extract was fractionated the fraction containing nucleotides inhibited lens differentiation, the margin of optic cup was a source of lens regeneration. If the optic vesicle was explanted 72 hours, 70 percent did develop a small lenticle from the margin of optic cup. A few hours later, alpha crystallin had disappeared from cup, such regeneration did not occur. It was suggested that alpha crystallin is a factor in early states of lens formation and that beta crystallin is involved in the forma
837
tion of fibers from the posterior pole at a later stage. PROTEIN METABOLISM I N T H E RABBIT COR NEA DR. R. C. FRENCH AND M R S . Z. D U M A :
Proteins make up over 80 percent of dry weight of the cornea. Labelled amino acids were injected into the anterior chamber, and their incorporation into the cornea of the rabbit was studied. C1* was used to label glycine and proline for this purpose, since these two amino acids form 50 percent of the amino-acid residue of the corneal pro tein. Rabbit stromal cells in tissue culture are found actively to incorporate the (^"-la belled glycine and proline. Heat-killed cells showed comparatively little activity. Amino-acid uptake, as shown by C14 up take of the endothelium, was twice as ac tive, and the epithelium four times as active, as that of the stroma. Uptake into the cornea from the anterior chamber was considered to be an active metabolic synthesis, rather than adsorption. This synthesis is inhibited by chlorampheni col in high concentrations. SILICONE 200 AND PHOTOCOAGULATION DRS.
W.
G.
ROMBOUGH
AND C.
B.
A method of replacing vitreous humor of rabbits with silicone 200, having a viscosity of 1,000 centistokes, was de scribed. The conjunctiva is incised five mm. behind the limbus and a silk suture is placed in the sciera. A radial two-mm. incision is made through the sciera and choroid and vitreous humor, 0.5 cc, is removed through a No. 18 blunt needle connected to a syringe. Using a new needle and syringe, 0.5 cc. of silicone 200 is then injected into the vitreous cavity. The preplaced suture is tightly drawn before removing the needle. Once the silicone was injected, it lay in the upper part of the vitreous cavity. Photo coagulation using a setting of GI06 was MORTIMER: