Transgenic mice with pigmented intraocular tumors: tissue of origin and treatment.

Purpose: To describe the cell of origin, tumor progression, light and electron microscopic appearance, immunohistochemical properties, and response to frequently used anticancer therapies in two transgenic models of intraocular melanoma.

Methods: Two lines of transgenic mice that develop pigmented intraocular tumors were produced with the SV40 T and t antigens under the control of the mouse tyrosinase gene. Tumors were sequentially studied and characterized by light microscopy, electron microscopy, and immunohistochemistry stains.

Superior cervical ganglionectomy in monkeys: light and electron microscopy of the anterior eye segment.

Morphological changes in the anterior eye segment of eight cynomolgus monkeys were investigated 2 days to 2.2 years after unilateral surgical superior cervical ganglionectomy (SCGx). SCGx was confirmed by histologic examination of the excised surgical specimen and persistent ipsilateral miosis.

The color of the human eye: a review of morphologic correlates and of some conditions that affect iridial pigmentation.

Iris color can be affected by a variety of ocular disorders. It is suspected that iris color may not remain constant throughout life. These observations have drawn attention to the morphologic correlates of iris color and its regulation.

Clinicopathologic correlation of intraretinal microvascular abnormalities.

Purpose: To define the cross-sectional morphology of intraretinal microvascular abnormalities, which previously have been described only in terms of trypsin digestion.

Material/methods: Fourteen vascular lesions of five patients with diabetic retinopathy were identified on fundus photographs and/or fluorescein angiograms and classified as intraretinal microvascular abnormalities. Eyes of these patients were obtained after the patients' deaths.

Melanocytes and iris color. Electron microscopic findings.

Objective: To quantitatively associate iris color with melanocyte pigment content.

Methods: Autopsy eyes were classified as uniform-blue, uniform-hazel, or uniform-brown or showing a darker peripupillary ring. Using electron microscopic images and computerized image analysis, area, number, and size of mature melanosomes within the perinuclear cytoplasmic area only or within perinuclear and peripheral cytoplasmic areas of the superficial stromal melanocytes combined were measured.

Melanocytes and iris color. Light microscopic findings.

Objective: To systematically evaluate morphologic differences in iris stroma that contribute to clinically perceptible differences in iris color, using immunohistochemical identification of stromal melanocytes and fluorescence microscopy.

Methods: Paraffin-embedded sections from 51 human irides were stained with S100a and fluorescein isothiocyanate. Cells were counted and scored as melanocytes or other.

Renin mRNA is synthesized locally in rat ocular tissues.

Components of the Renin Angiotensin System (RAS) have been detected in ocular tissues and fluids. The source of the ocular RAS proteins is unknown but possibilities include diffusion or leakage from the systemic circulation, specific uptake from the blood, or local synthesis. We have used RT-PCR and in situ hybridization (ISH) to show that renin mRNA is present in ocular tissues from 3 strains of rats.

Ocular renin angiotensin: EM immunocytochemical localization of prorenin.

Prorenin (PR) was localized by electron microscopic (EM) immunostaining of cryo-ultramicrotomy sections of human ciliary body and correlated with light microscopic immunostaining. Both layers of the ciliary epithelium contained the prohormone. However, density was much higher in the adjacent extracellular spaces, particularly in the vitreous cortex.

Sub-pigment epithelial membranes after photocoagulation for diabetic macular edema.

Objective: The chronic histopathologic effects of focal and grid argon laser photocoagulation were examined in eyes obtained at autopsy that had previously been treated for diabetic macular edema. The focus was on further characterizing fibrous sub-pigment epithelial membranes that previously had been shown to extend beyond burn edges.

Design: A total of 131 argon laser burns were evaluated in five eyes.

Systemic hypertension produces pericyte changes in retinal capillaries.

Purpose: The purpose of this study was to examine retinal capillaries and their pericytes that previous research suggests to be contractile. A contractile role regulating capillary blood flow may be more apparent when the vasculature is subjected to the stress of systemic hypertension.

Methods: Using ultrastructural morphometry and the myosin subfragment-1 technique, retinal capillaries of normal and hypertensive rats were measured at three different time points, early, intermediate, and late (24, 44, and 68 wk).

Levator aponeurosis elastic fiber network.

This light and electron microscopic study demonstrates an elastic fiber network (EFN) for the levator palpebrae superioris muscle complex, which forms an intricate insertion into the upper eyelid. The EFN is examined in the monkey, in a fresh exenteration specimen, and in fresh frozen cadaver specimens from both sexes of different age groups. Multiple elastic insertions of the levator aponeurosis and Muller's muscle attachment with well-organized elastic fibers are demonstrated using special staining techniques and serial microscopic sectioning.

Identification of orbital lymphatics: enzyme histochemical light microscopic and electron microscopic studies.

The presence of orbital lymphatics in the primate model is demonstrated using light and electron microscopic enzyme histochemistry. In addition, strictly morphological definitions of lymphatics, such as discontinuous basal lamina, thin and irregular walls, anchoring filaments, and attenuated endothelial cell cytoplasm, were applied. This study confirmed the presence of conjunctival lymphatics reported by others.

An ocular renin-angiotensin system. Immunohistochemistry of angiotensinogen.

The circulating renin-angiotensin system (RAS) is an important determinant in maintaining adequate systemic blood pressure, and it also may modify organ-specific blood flow. All recognized RAS components have been identified in the eye. In this study, angiotensinogen (ANG) was localized using an affinity-purified antibody and paraffin sections of seven human eyes.

Sympathetic nerve anatomy in the cavernous sinus and retrobulbar orbit of the cynomolgus monkey.

We present new information regarding the sympathetic nerve anatomy in the cavernous sinus and retrobulbar orbit of the cynomolgus monkey. Postganglionic sympathetic nerves were identified using an immunoperoxidase technique in which the primary antiserum was directed against tyrosine hydroxylase, the rate-limiting enzyme in norepinephrine synthesis. Our work is unique in adapting this staining method to paraffin-embedded tissue.

Clinicopathologic correlation of diode laser burns in monkeys.

One hundred twenty-five retinochoroidal photocoagulation burns, produced by a transpupillary diode laser (810 nm) in six eyes of three cynomolgus monkeys, were evaluated by clinicopathologic correlation for up to 9 weeks after laser treatment. Diode burns of clinical grade 2 strength were comparable to those described for argon laser. However, diode burns of clinical grade 3 strength produced choroidal changes more intense than those described for argon laser.

Parasympathetic denervation of the ciliary muscle following panretinal photocoagulation.

Cynomolgus monkeys underwent unilateral panretinal scatter photocoagulation (PRP) and/or nasal and temporal horizontal retinal meridional photocoagulation (HRMP) with xenon arc or argon or krypton laser light. Shortly thereafter, in the PRP-treated eyes, accommodative responsiveness to topical eserine and electrical stimulation of the Edinger-Westphal nucleus (EWN) was diminished, accommodative responsiveness to intramuscular (i.m.

Pericyte changes in branch retinal vein occlusion.

The model of experimental branch vein occlusion (BVO) in the monkey offers the opportunity to examine retinal capillaries under stress. Electron microscopic morphometry was done on 812 capillaries of 13 eyes of cynomolgus monkeys, comparing 579 capillary collaterals of 9 BVO eyes with 233 normal capillaries of 4 control eyes. The tissue underwent the myosin subfragment-1 technique to decorate and quantify bundles of actin filaments in capillary pericytes.

Immunocytochemical study of an eye with proliferative vitreoretinopathy and retinal tacks.

After an eye-wall resection for a choroidal melanoma, a 32-year-old woman had subsequent retinal detachment with proliferative vitreoretinopathy (PVR), and an unsuccessful attempt at repair with retinal tacks. Gross and light-microscopic examination of the globe revealed a total retinal detachment with extensive preretinal and subretinal membranes. The membranes surrounded the tack heads and extended in taut bands to form a tractional detachment of the pars plana.

Immunostaining of preretinal membranes for actin, fibronectin, and glial fibrillary acidic protein.

The frequency and extent of immunostaining for actin, fibronectin (FN), and glial fibrillary acidic protein (GFAP) were determined in 37 preretinal membranes (PRMs) obtained at vitrectomy from 35 patients with proliferative diabetic retinopathy (PDR) (n = 16), proliferative vitreoretinopathy (PVR) (n = 18), or idiopathic macular pucker (MP) (n = 3). All three proteins were detected in the vast majority of specimens (actin, 86%; FN, 95%; GFAP, 96%), although the extent of staining varied for each. Actin-FN co-localization was observed in all diagnostic groups on comparison of adjacent sections and in double-labeled sections.

Ocular renin-angiotensin: immunohistochemical evidence for the presence of prorenin in eye tissue.

Angiotensin II (A2) is a vasoconstrictor generated by the renin-angiotensin system. A2 appears to act also as an angiogenic factor. Recent evidence suggests that renin is synthesized at many tissue sites and may generate A2 locally.

Cystoid macular degeneration in experimental branch retinal vein occlusion.

Macular edema and collateral vessels were examined clinically and histopathologically up to 48 months after branch retinal vein occlusion in six eyes of five cynomolgus monkeys. In all six, central macular swelling and fluorescein leakage from the retinal vasculature were confined to the acute stage. However, histopathologically, at the chronic stage, only two maculas were completely recovered and unremarkable, whereas the other four showed variable degrees of cystoid degeneration and photoreceptor cell loss.

Focal photocoagulation of diabetic macular edema. A clinicopathologic case report.

This is the first reported clinicopathologic correlation of focal photocoagulation treatment in a diabetic patient treated as part of the Early Treatment of Diabetic Retinopathy Study (ETDRS). Twenty focal argon laser burns were evaluated clinically in their acute and chronic stages, and histopathologically more than 3 years after exposure. Damage profiles of the lesions were reconstructed from serial tissue sections.

The development of vitreous membranes and retinal detachment induced by intravitreal carbon microparticles.

We induced intravitreal cellular proliferation by injection of carbon microparticles (size 20-70 nm) into the vitreous of 21 eyes of 11 cynomolgus monkeys. Pathological changes were evaluated by light and electron microscopy. At 1 week, there was conspicuous cyclitis showing exudative separation of the nonpigmented and pigmented ciliary epithelium, inflammatory cells, mononuclear phagocytes, and premacular vitreous detachment.

Microvascular changes in experimental branch retinal vein occlusion.

Collateral vessel maturation and regional capillary nonperfusion were examined clinically and histopathologically up to 48 months after branch retinal vein occlusion (BVO) in a monkey model. Significant increases in endothelial density, but not pericyte density, were noted in both dilated and normal capillary caliber vessels in regions of collateral flow, independent of duration of BVO from 4 to 15 1/2 months. Patent capillaries in regions of hypoperfusion showed increased endothelial densities but decreased pericyte densities.