Effects of eye position on auditory localization and neural representation of space in superior colliculus of cats.

The maps of visual and auditory space within the superior colliculus are in approximate register both with each other and with the underlying motor maps associated with orienting responses. The fact that eyes and ears can move independently poses a problem for the sensorimotor organization of these two modalities. By monitoring eye and pinna positions in alert, head-fixed cats, we showed that the accuracy of saccadic eye movements to auditory targets was little affected by eye eccentricity (range +/- 15 deg) at the onset of the sound.

Protein kinase C activation during corneal endothelial wound repair.

In previous studies, the authors have shown that the two forms of cell translocation that occur during corneal endothelial monolayer wound repair can be pharmacologically separated. Epidermal growth factor (EGF) enhanced the breaking of cell-cell contacts and movement of individual cells from the wound edge, while indomethacin, an inhibitor of PGE2 synthesis, promoted cell enlargement and spreading of the confluent monolayer sheet into the wound defect. From these findings, the authors hypothesized that the two forms of cell translocation were stimulated by different but coordinately regulated second messenger systems.

Analysis of nonlinearities in the flicker ERG.

The electroretinogram (ERG) response to steadily flickering fields shows significant nonlinear components. These nonlinear components have been used to investigate the ERG. We find the following.

Adhesive mechanisms of the corneal epithelium.

The corneal epithelium adheres to the stroma through a series of linked structures termed collectively the adhesion complex. These structures include; intermediate filaments (keratin filaments) which are linked to the hemidesmosome; the hemidesmosome; the anchoring filaments which extend from the membrane at the hemidesmosome through the lamina lucida to the lamina densa region of the basement membrane; the anchoring fibrils which insert into the basement membrane from the stromal side; and the anchoring plaque on which anchoring fibrils terminate distal from their insertion on the basement membrane. Upon wounding, basal cells of the corneal epithelium disassemble their hemidesmosomes.

Aqueous humor cyclic AMP and circadian elevation of intraocular pressure in rabbits.

Rabbits entrained in a daily light-dark environment show a circadian elevation of intraocular pressure (IOP) around the onset of dark. It was reported that concentration of cyclic AMP (cAMP) in aqueous humor increases significantly during this time period. Whether or not the increase of ocular cAMP-mediated activities is related to the circadian elevation of IOP is unclear.

Adrenergic mechanism in circadian elevation of intraocular pressure in rabbits.

Stimulation of the ocular sympathetic nerves is essential for the circadian elevation of intraocular pressure (IOP) in rabbits. Adrenergic mechanisms that participate in this elevation of IOP around the onset of darkness were investigated using selective adrenergic agents. Unilateral topical administration of 0.

Collagens of the bovine vitreous.

The predominant structural components of the vitreous are collagenous fibrils. Prior biochemical analyses have been limited by incomplete solubilization of the constituent collagen types. The techniques described enable an effective separation and nearly complete solubilization of calf vitreous fibrils.

Endogenous hormonal changes and circadian elevation of intraocular pressure.

A unique circadian rhythm of intraocular pressure (IOP) occurs in laboratory rabbits housed in a light-dark environment. The IOP is low in the light and high in the dark. In 32 rabbits studied, the IOP was 18.

Best's macular dystrophy with a macular hole.

The occurrence of a macular hole with Best's dystrophy is an extremely rare finding with only one reported case in the literature. We wish to report two cases with typical Best's dystrophy in one eye and a macular hole in the contralateral eye. In one case the Pattern Reversal VER (PVER) was also recorded and graphed as an amplitude-check size function curve.

Biological control of primate macular pigment. Biochemical and densitometric studies.

The amounts of zeaxanthin (Z) and lutein (L), the carotenoids constituting the primate macular pigment, were measured in the central retinas of monkeys (Saimiri sciureus and Macaca fascicularis). Two independent methods--reverse-phase high-performance liquid chromatography (HPLC) and microdensitometry--were used for analysis of the same set of retinas. Most of the measurements were made on retinas that had been fixed by glutaraldehyde-paraformaldehyde perfusion of the animal.

Plasma carotenoids of monkeys (Macaca fascicularis and Saimiri sciureus) fed a nonpurified diet.

The major carotenoid pigments in the plasma and in a common, nonpurified diet of two species of monkeys (Macaca fascicularis and Saimiri sciureus) were measured. The xanthophylls, lutein, zeaxanthin, alpha-cryptoxanthin, and beta-cryptoxanthin, were the principal carotenoids in both the diet and the plasma. Lutein and zeaxanthin were abundant in the all-trans, the 9-cis, and the 13-cis geometrical isomers in the diet, but the 9-cis form was rarely measurable in plasma.

Chronic electrical stimulation of sympathetic nerves: effects on blood-aqueous barrier.

The effect of electrical stimulation of the sympathetic nerves on the blood-aqueous barrier was investigated in rabbits. The permeability of the barrier was assessed during either acute, chronic or following chronic nerve stimulation. During acute and chronic stimulation of the sympathetic nerves, fluorescein entered the anterior chamber at a rate significantly slower than in control eyes.

Lightness and brightness over spatial illumination gradients.

We extended our studies of lightness and brightness in complex scenes to cathode-ray-tube simulations of an array of 35 gray reflective patches under spatially varying illuminants. There were three illuminance profiles, an abrupt step, a linear gradient, and a simulation of side illumination, with nine steepnesses of each. In half the sessions observers adjusted a test patch at one end of the illumination gradient in order to match the lightness of a standard patch at the other end of the gradient.

Retinal vasculature of the fovea of the squirrel monkey, Saimiri sciureus: three-dimensional architecture, visual screening, and relationships to the neuronal layers.

The retinal vasculature of the fovea of squirrel monkeys was studied in retinal whole mounts and in sections of the same retinas. At the center of the fovea there is an approximately circular avascular zone surrounded by a set of terminal capillaries in the inner nuclear layer. Within the foveal depression, four capillary planes that bear a precise relationship to the neuronal organization appear in a specific sequence with increasing eccentricity.

Stromal degradation in vitamin A-deficient rat cornea. Comparison of epithelial abrasion and stromal incision.

Epithelial abrasions (3-mm diameter) and linear stromal incisions (50-75% depth) were made in vitamin A-deficient (A-) rat corneas to investigate what are contributory factors to the development of keratomalacia. Sixty-four rats were killed at various times after injury, and the corneas were histologically examined. In pair-fed control corneas, wounds healed without stromal degradation.

Central cholinergic stimulation affects ocular functions through sympathetic pathways.

Intracerebroventricular (ICV) injection of carbachol into the third ventricle of conscious rabbits increased pupil size and intraocular pressure (IOP). A significant increase of pupil size by 0.6-1.

Detoxification of Aflatoxins in Foods and Feeds by Physical and Chemical Methods .

Detoxification of aflatoxin contaminated foods has been a continuing challenge for the food industry. This article examines primarily the detoxification of aflatoxin B in foods and feeds. The sensitivity of aflatoxins to physical or chemical treatments is affected by many factors including moisture content, location of the toxins in the food, forms of the food, and interactions of the toxins with food components.

[Static microperimetry with the laser scanning ophthalmoscope].

We have used the scanning laser opthalmoscope (SLO) with a personal computer to develop static microperimetry techniques. They allow to see in real-time on a television monitor the precise retinal localization of the stimulus and fixation. The testing is performed under strict conditions.

Neuronal markers in rat retinal grafts.

Rat E15 retina was grafted to the retina of adult rat hosts. After varying survival times (1 week-6 months), grafts were stained by immunohistochemistry for neurofilament 160 kDa (NF), HPC-1 (an amacrine cell marker), choline acetyltransferase (ChAT), tyrosine hydroxylase (TH), glutamic acid decarboxylase (GAD) and somatostatin-28 (SS-28). The first differentiating graft amacrine cells (cholinergic and dopaminergic) could be seen 1 week after transplantation (corresponding to postnatal day 1 = P1).

Simultaneous pattern reversal ERG and VER recordings. Effect of stimulus field and central scotoma.

The effects of the sizes of the stimulus field and of an artificially created central scotoma on simultaneously recorded pattern-reversal electroretinogram (P-ERG) and pattern-reversal visual-evoked response (P-VER) were investigated. With an increase in the stimulus field from 4 degrees X 4 degrees to 12 degrees X 12 degrees, the amplitude of the P-ERG increased steadily. The amplitude of the P-VER also showed an increase up to a stimulus field of 6 degrees X 6 degrees or 8 degrees X 8 degrees, but showed no increase with further expansion of the stimulus field.

Retinal pigment epithelium wound closure in vitro. Pharmacologic inhibition.

Early-passage bovine retinal pigment epithelium (RPE) cells were grown to confluence in 24-well plates, and a central defect was created mechanically in the monolayer within quadruplicate wells, sequentially over 9 days. Closure of the wounded area occurred by single-cell migration of elongated RPE cells from the edge of the wound and subsequent cell proliferation. Ten days after wounding, the cultures were fixed, stained, and photographed, and the residual wound area was quantified by computerized planimetry.

Posterior vitreous detachment following panretinal laser photocoagulation.

A total of 30 eyes of 19 patients with type I diabetes, varying severity of retinopathy, and no posterior vitreous detachment (PVD) were studied clinically, and vitreous examination was performed by preset lens biomicroscopy. Follow-up was 4.0-7.

Pathologic changes in the exorbital lacrimal gland of the vitamin A-deficient rat.

Histologic changes in lacrimal glands of vitamin A-deficient (A-) and pair-fed control rats were compared. In A- lacrimal glands, secretory granules were strikingly diminished, and rough endoplasmic reticulum appeared somewhat atrophic. Nuclei of acinar cells were hyperchromatic and pleomorphic.

Overexpression of fibronectin induced by diabetes or high glucose: phenomenon with a memory.

To identify events and mechanisms that might contribute to the poor reversibility of diabetic complications, we examined whether diabetes or high glucose induces changes in gene expression and whether such changes outlast the presence of the metabolic abnormalities. The study focused on fibronectin because the increased amounts of this glycoprotein found in diabetic tissues and thickened basement membranes are as yet unexplained. In streptozotocin-induced diabetic rats, fibronectin mRNA levels were increased to 304 +/- 295% of control (mean +/- SD) in the kidney cortex (P less than 0.

Shiny multifocal chorioretinitis with papillitis.

We report a case of unilateral inflammation involving the retinal pigment epithelium-choriocapillaris complex and the optic disc, characterized by multiple, small, shiny, yellowish-white subretinal lesions involving the midperiphery of the retina and associated with optic disc edema. These lesions showed hypofluorescence in the early transit phase of the fluorescein angiogram and leakage in the late phase. Perivascular staining of the retinal vessels and diffuse optic disc leakage were also present.