The adrenergic receptors in man were analyzed using isolated sphincter, dilator, and ciliary muscle strips, dissected from eyebank eyes. The dilator is mainly alpha, the sphincter both alpha and beta, and the ciliary muscle predominantly beta adrenergic.
Beef eye anterior chambers were perfused with media containing radiolabeled glycogen precursors. Incorporation of 14C from 1-alanine-U-14C into corneal epithelium glycogen suggested the presence of a gluconeogenic pathway in the eye. Failure to isolate radioactive glucose from 1-alanine-U-14C-containing perfusate after passage through the anterior chamber strongly suggests a corneal site for this pathway.
This study reviewed the potential for survival of a pathogenic bacteria when inoculated into McCarey-Kaufman modified tissue culture media 199. A clinically isolated specimen of Staphylococcus aureus was selected and rabbit eyes inoculated with 0.1 ml. of the organism in a suspension of 1 to 3 x 10(-5). Upon enucleation 12 hours later no clinical signs of infection were noted. Limbal-conjunctival cultures were obtained on all eyes before and after application of the antibiotic. Corneas were stored in M-K media with standard penicillin-streptomycin added and cultured up to 48 hours. Our studies showed some recovery of the infecting organism from the media with topical antibiotic application but none following complete immersion of eyes in antibiotic. Direct cultures from corneal buttons taken 48 to 72 hours after antibiotic application by either method showed 1 to 3 colonies per plate in 25 per cent of eyes. In this study improperly applied antibiotic allowed some survival of S. aureus in the media.
Axonal transport in primate optic nerve axons was studied by autoradiography, scintillation counting, and electron microscopy under conditions of short-term intraocular pressure elevation. With elevation of intraocular pressure to 30 mm. Hg below mean arterial blood pressure, blockage of transport was detected within 2 hours by autoradiography and within 1 hour by electron microscopy. The earliest buildup of radioactively labeled protein and ultrastructurally visible cellular organelles was within the scleral lamina cribrosa. The degree of blockage, judged by amount of label buildup, increased with time. Some transported material traversed the lamina cribrosa despite pressure elevation at the level tested. Reversal of transport blockade occurred rapidly after normalization of intraocular pressure.
Some characteristics of children with xerophthalmia are described and the difference in age between those with serious corneal xerophthalmia and those showing milder conjunctival xerophthalmia is noted. The various public health measures instituted to prevent xerophthalmia are examined. The particular importance of protein in food given to severely malnourished children suffering from xerophthalmia is stressed and studies on enzyme activities which are enhanced in the xerophthalmic cornea are briefly noted.
The development of the macaque monkey fovea begins about 100 days before birth when a large number of ganglion cells accumulate in the retina temporal to the optic disc. The same region contains only cones in the outer nuclear layer. All of the cells in the three retinal layers delineated by the 1,600 nm wide pure-cone area will eventually redistribute and be included in the area of the adult fovea. Fifty days before birth, the foveal depression has begun to form by the peripheral displacement away from the fovea of first the retinal ganglion cells and, slightly later, the amacrine, horizontal, Midler, and bipolar cells. All of these cells occupy their adult location and the foveal pit is well formed shortly after birth. The cones begin to be displaced toward the fovea 50 days before birth and continue this movement until about 3 months after birth; the direction and amount of displacement of the foveal cone are shown by its elongated basal axon which always points peripherally. The period after birth is marked by a considerable elongation of all regions of the cone, with a concomitant decrease in width of the inner segment to half that at birth and a fourfold, increase in the number of cone inner and outer segments within the fovea.
The relationship of the concentration of glutathione (GSH) in lens epithelium to the transport of cations in the lens was studied by decreasing the level of GSH in the epithelium and monitoring subsequent effects in the lens on the distribution of cations, the activity of Na+-K+ ATPase and the uptake and efflux of 86Rb. Oxidation of GSH in cultured rabbit lenses was accomplished by the use of 1 mM tertiary butyl hydroperoxide (TBHP), a reagent which appears to be suitable for the specific oxidation of GSH in this tissue. The concentration of GSH found in the normal lens epithelium was estimated to be 64 mum per gram wet weight or nearly six times that present in the whole lens. A decrease in the concentration of GSH in lens epithelium of 60 per cent or more leads to an increase in hydration, a shift in the distribution of Na+, K+, and Cl-, a decrease in the activity of Na+-K+ ATPase, and a decrease in the active transport, and an increase in the passive diffusion of 86Rb. In the TBHP-treated lenses there is a rapid decrease in the production of lactate, possibly as a result of the inhibition of Na+-K+ ATPase, but the effect on the level of lens ATP is delayed and less pronounced. It appears that the adverse effect on membrane permeability caused by the oxidation of GSH is partially reversed when a high level of GSH returns to the epithelium. However, the decrease in active transport of 86Rb and the inactivation of Na+-K+ ATPase are not reversed by either regeneration of GSH in the tissue or by treatment with exogenous dithiothreitol and may indicate an irreversible conformational change in the enzyme initiated by the loss of the protective effect of GSH. The data indicate that a critical level of GSH is required in the lens epithelium for the maintenance of normal cation transport.
(1) In owl monkeys, where no yellow staining of the media is present, there are clear-cut ophthalmoscopic and histologic differences in the lesions produced by equal amounts of argon green and blue light. (2) The yellow staining of the macula causes differences in lesion intensity and depth when different wavelengths are used for photocoagulation. (3) In humans the influence of age on this difference is apparent.
Outflow facility responses to pilocarpine were determined in ten cynomolgus monkey eyes after disinsertion of the ciliary muscle from the scleral spur. The effect of large intravenous dose given on one occasion was compared to the effect of intense topical treatment for 18 to 24 hours on another occasion. The effect of the two modes of treatment differed from eye to eye, but were similar in the individual eye. In some eyes facility rose while in others it fell. The average effect of both treatments was very small.
Abnormal tear calcium concentrations, which might be expected in ocular and systemic disorders,may be obscured if tear calcium concentration varies with flow rate. The results of the present study indicated that tear calcium concentration is independent of flow rate with rates faster than those which occur with stimulated overflow tearing (i.e., 2 mu1 per minute), but with slower flow rates such as would be encountered with basal, nonstimulated tear flow, tear calcium concentration increases as flow rate decreases. In addition, at given flow rates, tear calcium concentration is the same as that in at least two components of tears, i.e., lacrimal gland fluid, uncontaminated by fluid from the other orbital glands, and fluid from the other orbital glands, uncontaminated by lcarimal gland fluid. It is apparent that only if calcium concentration is correlated with fluid flow rate will determination of calcium in tears and in the components of tears produce valid information not only about tear calcium levels in the presence of ocular and systemic diseases but also about the mechanism of secretion of calcium by the orbital glands.
A grating pattern presented to one eye of an individual capable of alternating suppression induces a visual aftereffect (contrast threshold elevation), even when the pattern is phenomenally suppressed from vision. This finding indicates that strabismic suppression occurs within the visual system after the site of the aftereffect, and points out a similarity between strabismic suppression and binocular rivalry suppression.
Rabbit corneas were subjected to MK-medium or moist-chamber storage for periods up to 7 days. Sodium, potassium, and chloride concentrations and hydration were measured. The hydration of corneas stored in MK medium was less than that of those stored in moist chambers. The sodium concentration of MK corneas remained stable for up to 7 days; the potassium concentration, however, decreased with increasingly longer periods of storage. Chloride concentrations quickly equilibrated with the high chloride level of MK medium. The concentration of sodium and chloride in moist chamber-stored corneas fell with progressively longer storage periods. Potassium showed an initial decrease in concentration followed by an increase in concentration that paralleled, and equilibrated with, the increasing acqueous humor concentration.
After topically administered nitrogen mustard the irritative effect on the pupil, intraocular pressure, protein concentration of the aqueous humor and on the vessels of the iris and conjunctiva was quantified. The protein level in aqueous was determined by refractometry. The degree of hyperemia of conjunctiva and iris was determined by measuring the amount of Evans blue dye present in the tissue minutes after intravenous administration. A reproducible relationship was obtained using these methods to evaluate the degree of irritation produced by nitrogen mustard.
Dose-response curves of increase in pupil size and decrease in intraocular pressure with topical epinephrine have been determined in the sympathetically denervated rabbit eye. Topical pretreatment with the catechol-O-methyl transferase inhibitor U-0521 potentiated the effects of epinephrine on both the pupil and pressure. These observations suggest a possible role for catechol-O-methyl transferase in the aqueous humor dynamics of the supersensitive eye. The possible use of the denervated rabbit eye as an experimental model for the glaucomatous eye in evaluating the ocular effects of adrenergic agents is discussed.
In rats with primary retinal degeneration, lens extraction combined with total retinal detachment provided a model for injection of a tracer of colloidal carbon into the subretinal space. Electron microscopy and acid phosphatase cytochemistry were subsequently used to analyze the ingestion of tracer by the retinal pigment epithelium. It was found that the attachment, ingestion, and digestion phases of the phagocytic process were apparently preserved. From this evidence it is suggested that there is no lack of phagocytic power in the retinal pigment epithelium of affected rat strains.
The efficiency of 5-iodo-5'-amino-2'5'-dideoxyuridine (AIU) in the therapy of experimental herpes keratitis in rabbits has been examined. Virus infections were established bilaterally in 40 animals using herpes simplex, type 1 (NIH strain 11124). Twenty-four hours after infection the rabbits were divided into five matched groups of eight and each group was treated, double-blind, with topical drugs at four-hour intervals for a total of 72 hours. The solutions instilled were: (1) saline; (2) IdUrd, 1 mg. per milliliter; (3) AIU, 1 mg. per milliliter; (4) AIU, 4 mg. per milliter; and (5) AIU, 8 mg. per milliliter. Each eye was examined daily for 12 days and graded independently by two ophthalmologists. Although IdUrd and AIU (8 mg. per milliliter) were effective therapeutically, IdUrd had a greater effect. The AIU at 1 and 4 mg. per milliliter were less active, but showed more rapid healing than the saline control. Viral recovery studies are consistent with the clinical observations. A second independent experiment, similar to that described above, gave essentially identical results. Although less potent than IdUrd, AIU does provide effective therapy for herpes keratitis.
A high incidence of keratoconjunctivitis was observed in a closed colony of inbred Lewis/Wistar rats. Clinical signs including blinking, ocular discharge, circumcorneal flush, corneal opacity, ulceration, pannus, hypopyon, and hyphema were observed at about three weeks of age. Acute disease subsided by six weeks of age, but some lesions progressed to low-grade chronic keratitis. Six per cent of affected rats developed megaloglobus, which usually appeared by three weeks of age. Lesions included focal or diffuse interstitial keratitis, corneal ulceration, anterior synechia, and inflammatory exudate in the anterior chamber. A high incidence of lenticular and retinal degeneration was associated with megaloglobus. Most affected rats also had harderian dacryoadenitis. Sialodacryoadenitis virus (SDA) was recovered from nasal washes, but not from affected eyes. Serological evidence indicated that SDA virus infection was widespread in the colony.
