Retrograde tracing studies of subdivisions of the orbicularis oculi muscle in the rhesus monkey.

Functionally and anatomically, the orbicularis oculi (OO) muscle can be subdivided in a pretarsal, a preseptal, and an orbital portion. In the rhesus monkey, fluorescent and neuronal retrograde tracing experiments were performed in the pretarsal or the orbital portion of the OO muscle, or both, using fast blue, diamidino yellow, and wheat germ agglutinin-horseradish peroxidase as tracers. The preseptal portion was not investigated because of close anatomical relationships to the other portions.

New indirect pathways subserving the pupillary light reflex: projections of the accessory oculomotor nuclei and the periaqueductal gray to the Edinger-Westphal nucleus and the thoracic spinal cord in rats.

The pupillary light reflex (PLR) is under the control of retinal ganglion cells projecting to the olivary pretectal nucleus (OPN). The OPN has a major projection to the Edinger-Westphal (EW) nucleus, which exerts its parasympathetic action on the iris musculature via the ciliary ganglion. The accessory oculomotor nuclei (AON) and the periaqueductal gray (PAG) receive input from the OPN and influence the PLR.

Detecting connectedness.

Natural visual images are typically composed of multiple objects, which need to be segregated from each other and from the background. The visual system has evolved to capture a great variety of cues that allow a meaningful segmentation of the visual input. One of these cues is connectedness.

Polarized secretion of IL-6 and IL-8 by human retinal pigment epithelial cells.

A number of cell types situated along interfaces of various tissues and organs such as the peritoneum and the intestine have been shown to secrete inflammatory cytokines in a polarized fashion. Retinal pigment epithelial (RPE) cells are positioned at the interface between the vascularized choroid and the avascular retina, forming part of the blood-retina barrier. These cells are potent producers of inflammatory cytokines and are therefore considered to play an important role in the pathogenesis of ocular inflammation.

Figure-ground activity in primary visual cortex is suppressed by anesthesia.

By means of their small receptive fields (RFs), neurons in primary visual cortex perform highly localized analyses of the visual scene, far removed from our normal unified experience of vision. Local image elements coded by the RF are put into more global context, however, by means of modulation of the responses of the V1 neurons. Contextual modulation has been shown to follow closely the perceptual interpretation of the scene as a whole.

Two families with dyshidrotic ectodermal dysplasia associated with ingrowth of corneal vessels, limbal hair growth, and Bitôt-like conjunctival anomalies.

Five cases from two unrelated families with a hitherto unknown combination of dyshidrotic ectodermal dysplasia with corneal vessel ingrowth, limbal hair follicles with hairs, and Bitôt-like spots in the conjunctiva are described. The corneal lesions were slowly progressive. In one pedigree, autosomal recessive inheritance is most likely, in the other there is uncertainty about the mode of inheritance.

Cystatins in tears of patients with different corneal conditions.

A presence of cystatins, inhibitors of cysteine protease, was investigated in tears of patients with different corneal pathologies. Tear fluid samples were collected with glass capillaries in 28 patients (28 eyes) and 15 healthy controls (15 eyes). Only after corneal transplantation (8) or in corneal dystrophy (6) but not after cataract extraction (5) or other traumatic conditions of the cornea (9) was a significant difference in inhibitory activity of cystatins measured in comparison with the 15 controls.

Cholesterol, phospholipid, and protein changes in focal opacities in the human eye lens.

Purpose: Focal opacities are signs of early cataractogenesis in the human lens. They progress slowly over a lifetime and may be precursors of mature cataracts. The authors analyzed changes in proteins, phospholipids, and cholesterol in these opacities using in situ techniques: Raman microspectroscopy, filipin cytochemistry for cholesterol, and transmission electron microscopy (TEM).

Deterioration of visual fields in patients with glaucoma with and without optic disc hemorrhages.

Objective: To evaluate visual field deterioration in patients with glaucoma with and without optic disc hemorrhages (DHs).

Design: A prospective study at quarterly base involving annual perimetry; mean follow-up of 9 years.

Setting: Outpatient department, nonreferral basis.

A gene for X-linked optic atrophy is closely linked to the Xp11.4-Xp11.2 region of the X chromosome.

The aim of this study was to identify the chromosomal location of the disease-causing gene in a family apparently segregating X-linked optic atrophy. A large family of 45 individuals with a four-generation history of X-linked optic atrophy was reexamined in a full ophthalmic as well as electrophysiological examination. A DNA linkage analysis of the family was undertaken in order to identify the chromosomal location of the disease-causing gene.

Localization of a novel X-linked progressive cone dystrophy gene to Xq27: evidence for genetic heterogeneity.

Clinical reexamination and DNA linkage analysis were carried out in an X-linked progressive cone dystrophy (XLPCD) family, previously described by Pinckers and Timmerman in 1981. In a large pedigree segregating XLPCD, by use of > or = 27 markers spanning the entire X chromosome, a novel locus for XLPCD was identified in Xq27. All other regions on the chromosome could be excluded.

Macrophages and MHC class II positive cells in the choroid during endotoxin induced uveitis.

Aims/background: Endotoxin induced uveitis has been regarded as a model for acute anterior uveitis and until now little was known about choroidal involvement. The aim of this study was to investigate changes in macrophages and MHC class II positive cells in the choroid of Lewis rats during endotoxin induced uveitis.

Methods: Choroid-sclera wholemounts were isolated from normal Lewis rats and at different time points--4, 8, 16, 24, 48, 72, and 96 hours, and 7, 10, and 14 days after a footpad injection of 200 micrograms of lipopolysaccharide (LPS).

Architecture of human corneal nerves.

Purpose: The corneal innervation, mainly analyzed in light microscopical studies, has been described as radially oriented stromal nerve bundles that ramify as leashes in the subbasal plexus. The current study aims to determine the orientation, the size, and the postmortem changes of the nerve fibers in the subbasal plexus of the human cornea.

Methods: Before processing for light and electron microscopy, the position of the corneas within the enucleated eyes of persons with melanoma and pairs of postmortem eyes was marked.

Influx of immunoglobulins from the vascular compartment into a grafted cornea.

Purpose: To determine the effect of a fresh corneal wound or a healed corneal scar on the immunodiffusion of immunoglobulins into the cornea.

Methods: F344 rats were immunized with human serum albumin (HSA) 1 week before an autologous rotational keratoplasty of the right cornea or 1 year after an autograft was performed. One group of rats also was treated with gentamicin-dexamethasone ointment in the grafted eye for 1 week after transplantation to reduce the postsurgical inflammatory signs.

The ultrastructure of the olivary pretectal nucleus in rats. A tracing and GABA immunohistochemical study.

The olivary pretectal nucleus is a primary visual centre, involved in the pupillary light reflex. In the present study an ultrastructural analysis was made of the olivary pretectal nucleus by means of separate, anterograde and retrograde tracing techniques and immunohistochemistry of gamma-aminobutyric acid. Large-projection neurons and two types of gamma-aminobutyric acid-immunoreactive (GABA-ir) neurons are observed in the olivary pretectal nucleus.

Fluorescein angiographic evaluation of the effect of latanoprost treatment on blood-retinal barrier integrity: a review of studies conducted on pseudophakic glaucoma patients and on phakic and aphakic monkeys.

Endogenous prostaglandins (PGs) have been claimed to play a role in the development of cystoid macular edema (CME). Two fluorescein angiographic studies evaluating the effect of latanoprost, a new ocular hypotensive PG analogue, on blood-retinal barrier integrity are, therefore, reviewed here. In the first study, six of eight unilaterally aphakic cynomolgus monkeys were treated bilaterally once daily for six months with 0.

Separation of fibres from the capsule enhances mitotic activity of human lens epithelium.

Proliferation and migration of lens epithelial cells is at the origin of after-cataract, currently the main side effect of cataract surgery. Extracapsular cataract surgery necessitates opening of the anterior lens capsule and removal of the lens fibres before an intraocular lens can be placed in the cleaned capsular bag. The present study was aimed at testing the potential of the lens capsule and the fibres to affect the mitotic activity of the lens epithelial cells in human donor eyes.

Near infrared light absorption in the human eye media.

Available literature on the spectral transmittance of the eye media in the infrared (IR) is insufficiently accurate to estimate the deposited doses, e.g. in view of light damage risks.

Interaction between nitric oxide and prostaglandin synthesis in the acute phase of allergic conjunctivitis.

Both nitric oxide and prostaglandins induce vasodilatation which is an important feature of local inflammation. The purpose of the study described here was to investigate a possible interaction between these two types of mediators in an experimental model of allergic conjunctivitis. A conjunctival allergic reaction was induced with antigen in sensitized guinea pigs.

Modulating wavelength discrimination in goldfish with ethambutol and stimulus intensity.

Wavelength discrimination in goldfish was measured behaviourally. Both acute application of ethambutol injected into the eye and chronic application by feeding the animals daily 25 mg ethambutol for 1 month had the same effect on wavelength discrimination in the range of 560-640 nm. This means that: (1) electrophysiological experiments, in which drug application is primarily acute, reflect the same disturbance as behavioural experiments, in which drug application is chronic; and that (2) the origin of the color vision defect must be retinal.

Conclusive evidence for a distinct congenital stationary night blindness locus in Xp21.1.

X linked congenital stationary night blindness (CSNBX) is a non-progressive retinal disorder characterised by decreased visual acuity and disturbance of night vision. CSNBX appears to be not only clinically but also genetically heterogeneous. On studying a single large family, we recently suggested the presence of a distinct locus for CSNBX in Xp21.

Corneal endothelium and growth factors.

Human corneal endothelium is characterized by a low regenerative capacity, mainly because of a low mitotic activity, and therefore complete regeneration of the endothelial layer after injury is precluded. A decrease in endothelial cell density and an abnormal cell mosaic, which may occur after many conditions, can compromise the integrity of the endothelial monolayer, resulting in corneal decompensation with reduced vision and eventual need for penetrating keratoplasty. It would be beneficial to have growth factors that can help to maintain or restore the integrity of this delicate endothelial monolayer by maintaining or increasing the endothelial cell density or to stimulate the regeneration during wound healing.