Retrobulbar anesthesia and eyelid closure--effect on corneal angiogenesis

We evaluated the effect of corneal anesthesia produced by retrobulbar injections of bupivicaine and epinephrine on corneal neovascularization in the rat. The eyelids were sutured closed to prevent dessication and ulceration of the insensitive corneas. The amount of corneal neovascularization induced in animals receiving a retrobulbar anesthetic did not differ from those receiving control solutions. However, rats receiving retrobulbar injections exhibited greater corneal neovascularization than those that did not. Rats that had their eyelids sutured or patched closed also had more neovascularization than animals that did not. Likewise, rats that had sutures placed in the upper and lower eyelids, without palpebral immobilization, manifested more neovascularization than rats without sutures. These studies suggest that corneal anesthesia does not affect neovascularization induced by silver/potassium nitrate cauterization and that retrobulbar injections and eyelid closure enhance corneal neovascularization.

Histopathology of silicone oil keratopathy in humans

Corneal endothelial decompensation is a frequent complication when silicone oil is used as a tamponade following vitrectomy for treatment of proliferative vitreoretinopathy in an aphakic eye. We evaluated the clinical, histopathological, and ultrastructural features of silicone oil-induced keratopathy in 10 patients who developed corneal complications requiring penetrating keratoplasty. Clinically, some cases showed corneal edema, corneal hypesthesia, endothelial opacification, band keratopathy, and peripheral corneal vascularization. Histopathologically, retrocorneal membranes were present, and different degrees of stromal hypercellularity, superficial stromal calcification, and vascularization were noted. The ultrastructural features of endothelial cell loss and retrocorneal membrane formation are consistent with changes previously reported in rabbits and cats receiving intracameral silicone oil injections.

12(S)-hydroxy-5,8,10,14-eicosatetraenoic acid is a more potent neutrophil chemoattractant than the 12(R) epimer in the rat cornea

12(R)-hydroxy-5,8,10,14-eicosatetraenoic acid [12(R)-HETE] is reported to be more potent than its epimer 12(S)-HETE as a chemoattractant for human neutrophils in vitro and following topical application to the skin. To assess the in vivo neutrophil chemoattractant potencies of 12(S)-HETE and 12(R)-HETE in the rat, we injected 1 microgram, 5 micrograms, or 10 micrograms of these eicosanoids into the corneal stroma. Rats were killed 12-15 hours after injection, and the number of neutrophils in the stroma was counted in a histological section of the cornea including the injection site. The number of neutrophils was significantly increased in corneas injected with 5 micrograms (+103% of control) or 10 micrograms (+456% of control) of 12(S)-HETE and in those injected with 10 micrograms of 12(R)-HETE (+111% of control). The neutrophilic infiltrate in corneas injected with 1 microgram or 5 micrograms of 12(S)-HETE was not significantly different from that in corneas injected with 1 microgram of leukotriene B4. The data for the 10 micrograms injections indicate that 12(S)-HETE is a more potent neutrophil chemoattractant than 12(R)-HETE in the rat cornea. Our results suggest that species or tissue specificity may determine the relative potencies of 12-HETE epimers as chemoattractants for neutrophils, and that 12(S)-HETE may be an important inflammatory mediator in the rat cornea.

The effect of oxygen on corneal neovascularization

Since tissue oxygen levels are believed to play a pivotal role in new vessel growth in several situations, we studied the effect of several oxygen concentrations (0, 10, 21, 50, 75, or 100%) on corneal vascularization induced in the rat by chemical cautery. We achieved this by perfusing known concentrations of oxygen through goggles fitted over both eyes of the rat after corneal cauterization. Neovascularization was measured in flat corneal preparations with India ink-filled vessels 4 days postcautery using computerized image analysis. The angiogenic response of rats whose eyes were continuously exposed to 0-75% oxygen were not significantly different from each other. The mean response in corneas exposed to 100% oxygen was 10-21% lower than all of the other groups, and this difference was statistically significant when compared to oxygen concentrations of 0, 21 and 75%. The reason for the inhibitory effect of 100% oxygen remains to be determined, but it may represent a toxic effect of oxygen free radicals on the vascular endothelium.

Effect of inhibitors of arachidonic acid metabolism on corneal neovascularization in the rat

We used computerized image analysis to evaluate quantitatively the ability of topically applied corticosteroids (dexamethasone sodium phosphate, prednisolone acetate), cyclooxygenase inhibitors (flurbiprofen, indomethacin, ketorolac), lipoxygenase inhibitors (REV 5901, esculetin, quercetin), and dual cyclooxygenase/lipoxygenase inhibitors (BW 755C, BW A540C) to reduce corneal neovascularization in the rat induced by silver/potassium nitrate cauterization. Significant decreases in the neovascular response were found with corticosteroids and cyclooxygenase inhibitors. A complete dose-response curve was performed for a representative compound from each class. Dexamethasone was found to be superior to flurbiprofen in its ability to reduce neovascularization in this model, while no significant inhibition was noted with either REV 5901 or BW 755C, even at high doses. We conclude that the corneal angiogenic response in this model can be reduced by inhibition of cyclooxygenase as well as by other mechanisms that are steroid-dependent but are, as yet, poorly defined.

The effects of total lymphoid irradiation upon corneal vascularization in the rat following chemical cautery

The effect of total lymphoid irradiation (TLI), a form of radiotherapy known to suppress the number of circulating lymphocytes, on corneal neovascularization was assessed in rats. The corneas of TLI-treated rats were cauterized with silver/potassium nitrate one day after delivering gamma irradiation in five equal fractions (10 Gy total dose). Corneal neovascularization was assessed quantitatively by computerized image analysis in corneal flat preparations 4 days after corneal injury following perfusion of the circulation with India ink. TLI reduced the total leukocyte, lymphocyte, neutrophil, and platelet counts below preirradiation levels. The number of circulating lymphocytes was reduced more than neutrophils and platelets. TLI caused a predominance of cytotoxic/suppressor lymphocytes. Tissue examinations 4 days after TLI disclosed an absence of the thymus, as well as a markedly reduced number and size of lymph nodes. TLI rats had less corneal vascularization than nonirradiated controls. Our findings are consistent with the hypothesis that leukocytes play an important role in the pathogenesis of corneal angiogenesis following chemical cautery, but this study does not indicate how TLI suppresses corneal neovascularization.

Intraocular pressure following intravitreal silicone oil injection

The clinical features of 100 consecutive cases and the histopathology of six enucleated eyes, all having undergone silicone oil injection for complicated retinal detachments, were studied with regard to the incidence and mechanisms of postoperative intraocular pressure changes. Preoperatively, five patients had glaucoma and 35 had hypotony (7 mm Hg or less). Immediately after surgery, 43 patients had glaucoma and 14 had hypotony, while seven had glaucoma and 39 had hypotony in the late postoperative period (average follow-up of 1 year). In most cases, the mechanism of intraocular pressure change did not appear to be directly related to the presence of silicone, but rather to the preoperative status of the eye and other aspects of the vitreoretinal surgery. When silicone was a factor, the resulting intraocular pressure appeared to represent a balance between mechanisms obstructing aqueous outflow (pupillary block and the reaction to silicone bubbles in the anterior chamber angle) and mechanisms reducing aqueous production (cyclitic membranes and retinal detachment).

Quantitation of corneal neovascularization using computerized image analysis

We have developed a method for quantitating corneal neovascularization, induced in anesthetized rats by silver nitrate/potassium nitrate cauterization, using a LeMont OASYS video input image analyzer. Corneal vessels are visualized by perfusing the upper half of deeply anesthetized animals with a mixture of 10% india ink, 11% gelatin in lactated Ringer's solution. The eyes are then rapidly cooled using a stream of compressed dichlorodifluoromethane (Freon) to solidify the gelatin mixture. Magnified images of flat preparations of the corneas are acquired using a television camera attached to a dissecting microscope. The images are electronically converted to digital form and the digitized data are stored in the image analyzer. The area of the cornea and blood vessels are independently determined by analyzing the digitized data as discrete values of varying shades of gray (gray-scale analysis). The area and gray scale of the injury and its distance from the corneoscleral limbus can also be measured to determine variability of location and intensity of the injury in different animals. This technique allows the area occupied by new blood vessels during studies on corneal neovascularization in rats to be rapidly quantitated.

Primary orbital leiomyosarcoma. A case report and review of the literature

An 82-year-old woman presented with a five-week history of painless proptosis. Results of clinical evaluation, including computed tomography, were consistent with a benign orbital tumor. Biopsy followed by surgical resection disclosed leiomyosarcoma. We reviewed the literature and studied the clinical spectrum of this rare disease of the orbit.

Retinal toxicity of cyanoacrylate tissue adhesive in the rabbit

N-butyl-2-cyanoacrylate tissue adhesive was injected into the preretinal space of rabbit eyes to study potential toxicity to the retina. Application of 3.3-10.0 ul of cyanoacrylate tissue adhesive showed localized but definite retinal toxicity. White halos appeared surrounding the preretinal cyanoacrylate immediately after injection with a gradual evolution of the white areas into pigmentary scars by 1 month. Histological examination confirmed severe focal necrosis of the retina. No identifiable distant toxic effects or electrophysiologic changes were observed during the 6-month follow-up period.

Histopathologic and immunochemical features of lattice corneal dystrophy type III

We examined seven corneas from five patients with a new form of lattice corneal dystrophy (designated lattice corneal dystrophy type III) by light and electron microscopy. Numerous amyloid deposits were scattered throughout the corneal stroma, some of which were much larger than those usually observed in either lattice corneal dystrophy type I or II; these were located predominantly midway between the epithelium and the endothelium. Image analysis disclosed that the cross-sectional size of the large stromal amyloid deposits was significantly greater than those in age-matched patients with lattice corneal dystrophy type I. All patients had a discontinuous band of amyloid (15 to 25 micron wide) in the superficial stroma beneath Bowman's layer, which usually had only one or two small disruptions. Descemet's membrane and the endothelium were normal. The stromal deposits, which were composed of 10-nm diameter fibrils typical of amyloid, stained positively with Congo red after the histologic sections were pretreated with dilute potassium permanganate. Immunohistochemical studies on formalin-fixed, paraffin-embedded tissue indicated that only some deposits reacted weakly with antibodies to amyloid protein AA. The deposits stained positively with antibodies to protein AP and negatively with antibodies to kappa and lambda immunoglobulin light chains.

Improvement in efficacy of corticosteroid therapy in an animal model of proliferative vitreoretinopathy by pretreatment

Intraocular injection of the corticosteroid triamcinolone acetonide reduces the incidence of retinal detachment in rabbit eyes injected with tissue-cultured fibroblasts. When the steroid was injected simultaneously with the cells, a reduction of retinal detachment from 93% (control) to 75% (treated) was achieved on day 28. When the steroid was injected 24 h preceding cell injection, the reduction of retinal detachment was from 85% (control) to 43% (treated). The development of retinal detachment is caused by proliferation of injected fibroblasts. Reduction of this proliferation is probably achieved partially through direct inhibition of mitosis, but more important may be the reduction of the reactive inflammatory process.

Experimental transvitreal cyanoacrylate retinopexy in a primate model

We evaluated the use of transvitreal cyanoacrylate retinopexy in the treatment of experimental rhegmatogenous retinal detachment during vitreous surgery in the cynomolgus monkey. The chorioretinal adhesions produced with cyanoacrylate tissue adhesive as compared with those produced by transscleral retinal cryopexy were more rapid in onset as well as stronger. To test the efficacy of cyanoacrylate retinopexy further, a 360-degree peripheral retinectomy was created in five eyes with circumferential cyanoacrylate application to the posterior retinal edge. The cyanoacrylate retinopexy did not prevent the development of proliferative vitreoretinopathy with traction retinal detachment, but in three of the eyes the tissue adhesive continued to maintain retinal apposition to the retinal pigment epithelium at the retinotomy edge. Histologic examination of the retinas disclosed a foreign body reaction adjacent to the cyanoacrylate sites, but there was no evidence of any distant effects caused by the tissue adhesive.

Neovascular glaucoma associated with an iris melanoma. A clinicopathologic report

A 48-year-old man had uniocular neovascular glaucoma, with the only apparent predisposing factor being a primary epithelioid melanoma of the iris. The new vessels disappeared following total excision of the tumor. These findings have implications regarding the mechanisms of neovasculogenesis.

Cholinergic stimulation of phosphatidylinositol hydrolysis by rat corneal epithelium in vitro

Phosphatidic acid (PA) is an obligate intermediate in the phosphatidylinositol (PI) cycle and may serve as a sensitive marker for this pathway of reactions. Previously, we have shown that acetylcholine (ACh) stimulates formation of labeled PA in whole rat corneas whose phospholipids were prelabeled with [14C]arachidonate. To determine which layer of the cornea exhibits the ACh effect, intact epithelium was isolated from the rest of the corneal tissue (designated "stroma/endothelium") by incubating rat corneas with neutral protease and then stripping off the epithelium using forceps. The epithelium was ultrastructurally normal and avidly incorporated [14C]arachidonate into phospholipids; the stroma/endothelium had only trace incorporation. [14C]Arachidonyl-PA formation by the epithelium was significantly increased after a 37 second (+58%) and was maximal after a 5.0 minute (+188%) incubation in the presence of 1 mM ACh. The stimulation by ACh was blocked by atropine and scopolamine but not by d-tubocurarine. The epithelium also incorporated significant quantities of [3H]inositol into phosphatidylinositol (PI), phosphatidylinositol monophosphate (PIP), and phosphatidyl-inositol bisphosphate (PIP 2). When [3H]inositol-labeled epithelia were incubated for 5 minutes with 1 mM ACh, [3H]inositol monophosphate (IP) was increased 200%, [3H]inositol bisphosphate (IP2) was increased 225%, and [3H]inositol 2 trisphosphate (IP3) was increased 74%. These results suggest that muscarinic cholinergic receptors may be an important regulator of the PI cycle in corneal epithelium and thus may affect intracellular calcium mobilization and epithelial proliferation and regeneration.

Ocular rosacea

The demographic, clinical, and histopathologic characteristics of ocular rosacea are reviewed, with emphasis on examination of the skin in patients with external ocular disease. Since no single clinical or pathological hallmark of rosacea exists, a proposed point system for diagnosis is presented. Studies of pathogenesis reveal that no single unifying hypothesis accounts for all the expressions of ocular rosacea. Reports of treatment with tetracycline and other antibiotics demonstrate efficacy, although the mechanisms of action of these drugs are not known. More recently, other classes of drugs, including isotretinoin and hexachlorocyclohexane, have proven to be effective in dermatologic manifestations of rosacea, but effects on ocular manifestations are unknown.

Fatal pulmonary bile embolism following acute acalculous cholecystitis

A 52-year-old man died during reoperation for bleeding after the development of acute postoperative acalculous cholecystitis. While the liver was being manipulated during surgery, the pulmonary artery diastolic pressure increased suddenly, cardiac output and blood pressure decreased, and soon afterward the patient had a cardiac arrest from which he could not be resuscitated. During resuscitative efforts, the maximum partial arterial oxygen pressure achieved was only 55 mm Hg despite 100% inspired oxygen. At autopsy, bile aggregates were found within necrotic liver parenchyma, portal and central vein branches, and numerous pulmonary arterioles and capillaries. The pulmonary arterial bile most likely resulted from embolization of inspissated hepatic bile aggregates during surgical manipulation.

Cholinergic stimulation of phosphatidic acid formation by rat cornea in vitro

The cornea has one of the highest acetylcholine (ACh) concentrations of any tissue but the function of the ACh has remained enigmatic. During studies on corneal arachidonic acid metabolism, we observed that ACh stimulates formation of labeled phosphatidic acid in rat corneas whose phospholipids were prelabeled with [14C]arachidonate. ACh did not affect the metabolism of free [14C]arachidonate. [14C]Arachidonyl-phosphatidic acid formation was doubled after 10 min of incubation in the presence of ACh concentrations of 10(-4) M or greater. The stimulation by ACh could be completely blocked by atropine and scopolamine and partially blocked by d-tubocurarine. These studies suggest that intact rat cornea has muscarinic cholinergic receptors and that the enzymes of the inositol phospholipids pathway are present since phosphatidic acid is an obligatory intermediate in that cycle of reactions.

Ocular cicatricial pemphigoid with granular IgA and complement deposition

A 65-year-old woman developed chronic redness of both eyes, and, over the ensuing 2 1/2 years, she had progressive conjunctival scarring with symblepharon formation. Other mucosal surfaces were not involved. A conjunctival biopsy specimen 12 months following onset of her disease showed areas of epithelial separation from the basement membrane zone as well as subepithelial chronic inflammation and scarring. Two years later, another conjunctival biopsy specimen showed granular deposition of IgA and C3 along the epithelial basement membrane zone using direct immunofluorescent staining. Electron microscopy confirmed the presence of deposits that were morphologically consistent with antigen-antibody complexes. These findings suggest that antigen-antibody (IgA) immune-complex deposition may provide an alternative pathogenetic mechanism to basement membrane zone autoantibody formation for development of progressive conjunctival scarring.

Cutaneous T-cell lymphoma presenting as a rapidly enlarging ocular adnexal tumor

A 63-year-old man, in good health previously, developed swelling and erythema of the right upper eyelid which progressed to involve both eyelids and surrounding tissues. After one month, he had a 9.0 x 9.0 x 3.5 cm mass despite two attempts at incisional drainage and treatment with antibiotics. Multiple asymptomatic erythematosus nodules (2-3 cm in diameter) developed on his back, trunk, and arms four weeks after onset of the eyelid erythema and swelling. Biopsies of two upper back papules and the eyelid disclosed cutaneous T-cell lymphoma, a lymphoproliferative malignancy of thymus derived lymphocytes originating in the skin. Systemic chemotherapy resulted in a marked decrease in the ocular adnexal mass but lymphomatous meningitis and quadriplegia developed. The patient died four months later; an autopsy was not performed. This case demonstrates that cutaneous T-cell lymphoma may rarely have its initial manifestation as a rapidly enlarging eyelid tumor.

Pyoderma gangrenosum involving the eyelid

A 62-year-old man was seen with an ulcer of the left upper eyelid of two weeks' duration. Over the previous 40 years, similar ulcers had intermittently developed elsewhere on his skin and spontaneously resolved over several months leaving atrophic scars. A biopsy specimen of the eyelid lesion showed epidermal ulceration with acute inflammation and liquefactive necrosis of the underlying dermis. Microorganisms and vasculitis were not present. On the basis of the clinical history and a compatible biopsy specimen, the diagnosis of pyoderma gangrenosum was made. This is an uncommon, idiopathic, ulcerating skin disease that may also have ocular manifestations. Eyelid ulcers have not previously been reported, to our knowledge. The diagnosis is established by clinical history and exclusion of other causes of ulceration.

Identification of calcium oxalate crystals using alizarin red S stain

Calcium oxalate crystals stain with alizarin red S at a pH of 7.0 but not at a pH of 4.2. In contrast, calcium phosphate and calcium carbonate stain at a pH of both 7.0 and 4.2. This difference allows presumptive identification of calcium oxalate deposits. The identity of calcium oxalate can then be confirmed by its insolubility in 2M acetic acid, since both calcium carbonate and calcium phosphate are soluble. We have applied this procedure for several years and have found it to be a rapid, reliable, and technically simple procedure for distinguishing calcium oxalate from other calcium deposits.

Mitomycin-induced hemolytic-uremic syndrome

Four patients who took the antitumor agent mitomycin manifested microangiopathic hemolytic anemia, thrombocytopenia, and renal failure. At autopsy, kidneys from all four patients had a microangiopathy typical of the hemolytic-uremic syndrome (HUS), with thromboses in glomerular capillaries and arterioles, fibrin deposition in mesangium, and prominent cellular intimal proliferation of the interlobular arteries. Development of the HUS was an important factor contributing to death in all four patients. From a review of the literature and our initial results of a randomized chemotherapy protocol for metastatic adenocarcinoma of the colorectum, it appears that mitomycin was the most likely cause for the development of the HUS in these patients. As more patients are being treated with mitomycin, particular care must be taken to monitor them for development of a drug-induced HUS.

Controlled aspiration of subretinal fluid in the diagnosis of carcinoma metastatic to the choroid

Carcinoma metastatic to the choroid was diagnosed in three patients by cytopathologic examination of subretinal fluid. The specimen was obtained using a scleral depressor modified to allow controlled aspiration of subretinal fluid through a sharp, angled, 30-gauge needle. This new method provides a useful tool for accurate diagnosis of carcinoma metastatic to the choroid in cases where the diagnosis is in question.