Outflow characteristics of isolated anterior segments of human eyes.

Purpose: To evaluate the relationship between intraocular pressure (IOP) and flow through the trabecular meshwork in isolated anterior segments of human eyes. Outflow facility (C) is thought to decrease proportionally with increasing IOP in human eyes in vivo and in vitro.

Methods: Twenty-nine eviscerated human anterior segments were perfused with ascending and descending pressure sequences in a stepwise fashion (range, 4 to 40 mm Hg); 11 of the 29 eyes were treated similarly after 20 hours of perfusion at 12 mm Hg.

Innervation of the lacrimal gland in the cynomolgous monkey: a retrograde tracing study.

Retrograde transport of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) was used to study the localisation of neurons that innervate the lacrimal gland of the cynomolgous monkey. WGA-HRP-labelled neurons were localised in the ipsilateral trigeminal, superior cervical and ciliary ganglia and in the ipsilateral and contralateral pterygopalatine ganglia. In the trigeminal ganglion WGA-HRP-labelled somata were found in the ophthalmic part (18%) and the maxillary part (5%).

Serologic and polymerase chain reaction analysis of intraocular fluids in the diagnosis of infectious uveitis.

Purpose: Infectious uveitis entities are usually rapidly progressive blinding diseases that can be prevented by prompt administration of specific antimicrobial therapy. With the aim of improving early diagnosis in patients with infectious uveitis, intraocular fluid samples from patients with sight-threatening posterior uveitis were investigated to determine the causative agent.

Methods: Thirty-eight patients with acquired immunodeficiency syndrome (AIDS) and retinitis, eight immunosuppressed patients with retinitis, 16 immunocompetent patients with acute retinal necrosis, and 22 immunocompetent patients with toxoplasmic retinochoroiditis were analyzed by polymerase chain reaction for the presence of herpesviruses and Toxoplasma gondii DNA and for local antibody production against these microorganisms.

Nitric oxide plays a role as a mediator of conjunctival edema in experimental allergic conjunctivitis.

The role of nitric oxide in allergic conjunctivitis was studied in a guinea pig model. The eyes of sensitized guinea pigs were challenged with ovalbumin (20 micrograms per eye) or histamine (20 micrograms per eye). Synthesis of nitric oxide (NO) was inhibited using L-NAME (200 micrograms per eye) or aminoguanidine (200 micrograms per eye).

Ultrastructural organization of human corneal nerves.

Purpose: Although the human cornea is densely innervated, observations of the nerve fiber distribution and ultrastructure are scarce. This study aimed to provide a detailed electron microscopic analysis of nerve fibers in the central and peripheral human cornea.

Methods: Samples from seven fresh corneas, obtained from the eyes of persons with melanoma, were processed for light and electron microscopic examinations.

Robinson's Computerized Strabismus Model Comes of Age.

In this article we review our further development of D.A. Robinson's computerized strabismus model.

Coherence in localized visual evoked potentials (VEPs) to spatial stimulus attributes (orientation and displacement) in man.

The purpose of this study was to compare visual evoked potentials (VEPs) of striate-peristriate and Cz to posterior parietal, especially IPL's supramarginal (Su) and angular (Ang, Ano, and Ant) leads in response to human face spatial attributes attend-task, to assess the concern of the former with basic features versus the latter's spatial attributes "rotated" rightwards, leftwards, or oblique (unusual angle of sight) or nodal one (eye)- and two-item, eye/mouth displacement. Monopolar cranially derived VEPs were recorded bihemispherically from six adults using 12 electrode arrays 1.5 to 2 cm apart.

Elevated serum angiotensin-converting enzyme activity in onchocerciasis.

Our objective was to measure serum angiotensin-converting enzyme (ACE) activity in patients with onchocerciasis. Serum ACE activity is commonly used in the diagnosis and follow-up of patients with sarcoidosis. However, serum ACE activity can also be elevated in a number of other granulomatous disorders.

Calcium distribution in the human eye lens.

The distribution of calcium in the human eye lens was investigated using the oxalate-pyroantimonate technique. In epithelial cells and superficial cortical fibers calcium is sequestered and tightly bound to proteins in the endoplasmic reticulum, nuclear envelope, Golgi cisterns and mitochondria. In intermediate fibers these cell organelles are broken down and the liberated calcium is ionically bound to the phospholipids at the extracellular side of the fiber-limiting membrane.

Sympathetic innervation of the rat choroid: an autoradiographic tracing and immunohistochemical study.

The sympathetic innervation of the choroid was investigated by means of the anterograde tracer 3H-leucine, injected into the rostral part of the superior cervical ganglion. The tracer was autoradiographically visualized at the light- and electron-microscopic levels. Labelled unmyelinated fibres were found in the choroid and labelled terminals were observed in close proximity to the smooth muscle cells of arterioles.

Fine mapping of the autosomal recessive retinitis pigmentosa locus (RP12) on chromosome 1q; exclusion of the phosducin gene (PDC).

In a previous study on a large pedigree from a genetically isolated population in the Netherlands, we localized a gene for autosomal recessive retinitis pigmentosa with paraarteriolar preservation of the retinal pigment epithelium (PPRPE) on the long arm of chromosome 1. In this study, we present an integrated genetic map of the target region. The resulting genetic order of the markers was used to construct haplotypes and to screen for key-recombinants in the pedigree.

Macrophages in the retina of normal Lewis rats and their dynamics after injection of lipopolysaccharide.

Purpose: To investigate the density, distribution, and morphology of macrophages (bone marrow-derived microglia) and major histocompatibility complex (MHC) class II-positive cells in the retina of Lewis rats and the dynamics of these cells after systemic lipopolysaccharide (LPS) injection.

Methods: Immunohistochemistry was carried out using monoclonal antibodies specific to monocytes and macrophages (ED1, ED2) and MHC class II-positive cells (OX-6) on whole-mounts of the retina obtained from Lewis rats before and at different time points after footpad injection of 200 micrograms of LPS.

Results: The inner layers of the normal retina contained a network of macrophages, whereby ED1 and ED2 staining revealed similar results.

Novel aspects of the ultrastructural organization of human corneal keratocytes.

Purpose: Proper functioning of the endothelium and proper structural organization of the keratocytes and collagen bundles are of ultimate importance for transparency of the cornea. The role of the endothelium has been investigated extensively, whereas the role of the keratocytes is still unclear. Detailed knowledge on the ultrastructural organization of keratocytes and the relationship between keratocytes and collagen bundles is as essential for understanding corneal transparency as is knowledge of endothelial functioning.

The mitochondrial DNA mutation ND6*14,484C associated with leber hereditary optic neuropathy, leads to deficiency of complex I of the respiratory chain.

The electron transfer activity of Complex I of the respiratory chain and Complex I-linked ATP synthesis were investigated in leukocytes of four males affected by Leber hereditary optic neuropathy and a mutation in the ND6 gene at nucleotide position 14,484 of mtDNA. The electron transfer activity in leukocytes of the patients was about 35% of that in control leukocytes, whereas the Complex I-linked ATP synthesis showed a decrease of only about 20%. This demonstrates that all three mtDNA mutations that are clearly associated with Leber hereditary optic neuropathy result in deficiency of Complex I.

Calcium localization and ultrastructure of clear and pCMPS-treated rat lenses.

Purpose: The sulfhydryl complexing agent p-chloromercuri-phenylsulfonate (pCMPS) has been shown to increase lens membrane permeability, Na+ and Ca2+ content, and light scatter in the rat lens in vitro. This study aimed to investigate the ultrastructural changes accompanying the increase in light scatter. In addition, high-resolution histochemistry was used to study the cellular distribution of Ca2+ in normal and cataractous lenses.

Nitric oxide induces vascular permeability changes in the guinea pig conjunctiva.

The role of nitric oxide (NO) as an inflammatory mediator in the mechanism of increased microvascular permeability was examined in a guinea pig model of allergic conjunctivitis. Topical challenge with antigen, compound 48/80, histamine or platelet activating factor (PAF) resulted in a marked increase of the conjunctival vascular permeability. Vascular permeability was determined by measuring the albumin content in the lavage fluid of the challenged eyes after 30 min.

Efferent synaptic organization of the olivary pretectal nucleus in the albino rat. An ultrastructural tracing study.

In this study an ultrastructural analysis was made of the efferent projections of the olivary pretectal nucleus in the rat. The anterograde tracer Phaseolus vulgaris leucoagglutinin was injected iontophoretically into the olivary pretectal nucleus. Ascending and descending pathways were studied.

Efferent projections of the olivary pretectal nucleus in the albino rat subserving the pupillary light reflex and related reflexes. A light microscopic tracing study.

The olivary pretectal nucleus is a primary visual centre sensitive to luminance changes. It is involved in the pupillary light reflex, the consensual pupillary light reflex and related reflexes, such as the lid closure reflex whereby pupillary constriction takes place. Since the olivary pretectal nucleus is a small nucleus, previous studies using degeneration, horseradish peroxidase and radioactive amino acid tracing were limited regarding to the exclusiveness of the projections from the olivary pretectal nucleus.

Efficient DNA carrier detection in X linked juvenile retinoschisis.

Juvenile retinoschisis is a rare, X linked hereditary vitroretinal degeneration. Female carriers of the disease do not develop any ocular abnormalities. Therefore, carrier detection by DNA analysis is extremely useful for these females.

Long term ocular and neurological involvement in severe congenital toxoplasmosis.

Aims: This study was set up to determine the long term ocular and systemic sequelae in patients with severe congenital toxoplasmosis.

Methods: Cross sectional and retrospective study of 17 patients with severe congenital toxoplasmosis.

Results: In addition to chorioretinitis (100%), the most common abnormal ocular features were optic nerve atrophy (83%), visual acuity of less than 0.

Multipoint linkage analysis and homogeneity tests in 15 Dutch X-linked retinitis pigmentosa families.

Linkage analysis and homogeneity tests were carried out in 15 Dutch families segregating X-linked retinitis pigmentosa (X L R P). The study included segregation data for eight polymorphic DNA markers from the short arm of the human X chromosome. The results of both multipoint linkage analysis in individual families and heterogeneity analysis support the view that there are only two X L R P loci on the short arm of the human X chromosome, with one locus near the OTC gene and one in the vicinity of DXS255.

New approach to assess the cholesterol distribution in the eye lens: confocal Raman microspectroscopy and filipin cytochemistry.

Confocal Raman microspectroscopy (CRM) is a non-invasive, non-destructive, and sensitive analytical tool for the study of some aspects of the molecular organization of cells and tissues with high spatial resolution. Filipin, a polyene antibiotic, specifically binds to cholesterol, and its molecular structure predicts it to be Raman-active. The aim of the present study was to assess the potentialities of a combined CRM-filipin approach to study the distribution of cholesterol in the human eye lens.

Localization of a novel X-linked congenital stationary night blindness locus: close linkage to the RP3 type retinitis pigmentosa gene region.

X-linked congenital stationary night blindness (CSNBX) is a non-progressive retinal disorder characterized by decreased visual acuity and loss of night vision. CSNBX is clinically heterogeneous with respect to the involvement of retinal rods and/or cones in the disease. In this study, we localize a new locus for CSNBX to Xp21.

HLA typing in congenital toxoplasmosis.

HLA-A, HLA-B, HLA-C, and HLA-D typing was performed in 47 mothers of patients suffering from ocular toxoplasmosis to investigate whether an immunogenetic predisposition exists for developing congenital toxoplasmosis in their offspring. No significant association between any HLA antigen was observed in the mothers of patients with ocular toxoplasmosis, although a total absence of the HLA-B51 antigen was found in this group. HLA-A, HLA-B, and HLA-C typing was also performed in their children (52 patients with ocular toxoplasmosis), to investigate a possible relation between the severity of ocular toxoplasmosis and an eventual immunogenetic factor.