Uptake and anterograde axonal transport of wheat germ agglutinin from retina to optic tectum in the chick.

The uptake and anterograde axonal transport of 125I-wheat germ agglutinin (WGA) has been investigated in the visual system of the chick. In order to obtain a marker with specific and homogeneous binding properties, the iodinated lectin was affinity purified by passage over an N-acetylglucosamine (NAcGlu)-Sepharose column after iodination. 22 h after vitreal injection of the purified 125I-WGA, radioactive label was found accumulated in the retinoreceptive layers of the contralateral optic tectum. Gel electrophoresis of tectal homogenates revealed that greater than 80% of the retrieved label ran in a band which comigrated with native WGA. In chicks injected with the fraction of the iodinated preparation that failed to bind to the affinity column, there was no evidence of tectal labeling. These findings support the hypothesis that WGA is selectively taken up by chick retinal ganglion cells and transported intact in an anterograde direction to their axon terminals in the contralateral optic tectum. This raises the possibility that constituents of perikaryal membrane, i.e., lectin receptors, are transported in an anterograde direction by chick retinal ganglion cells.

A latent, nonpathogenic HSV-1-derived vector stably expresses beta-galactosidase in mouse neurons.

A genetically engineered herpes simplex virus variant was constructed for use as a stable gene vector for neurons. To inhibit replication, the agent possessed a deletion in the immediate early gene ICP4, and to minimize reactivation from the latent state, the gene encoding the latency-associated transcript was deleted. The E. coli beta-galactosidase gene under the control of the Maloney murine leukemia virus long terminal repeat promoter was inserted into the ICP4 region. When introduced into the peripheral nervous system, this virus established latent infections and stably expressed beta-galactosidase in primary sensory neurons. Expression of beta-galactosidase over a more limited time period was observed when the latent infection was established in motor neurons of the hypoglossal nucleus. Agents of this general design have considerable potential for use as gene vectors for studies of neuronal function and correction of genetic defects affecting neurons.

Herpes simplex viral infection of the mouse trigeminal ganglion. Immunohistochemical analysis of cell populations.

Several distinct populations of sensory neurons in the ophthalmic region of the mouse trigeminal ganglion have been identified by their reactivity to antibodies raised against substance P (SP), calcitonin gene-related peptide (CGRP), cell-surface glycoconjugates SSEA3 and LD2, and the plant lectin, Bandeiraea simplicifolia lectin 1, isolectin 4 (BSIL4). Thirty-six percent of the neurons in the ophthalmic portion of the mouse trigeminal ganglion express CGRP and 17%, SP. All neurons that express SP also express CGRP. Forty percent of the neurons in the ophthalmic region of the ganglion are recognized by monoclonal antisera to SSEA3, and 66% of this population also express the neuropeptides SP or CGRP. The neuronal population recognized by BSIL4 is identical to the population with the LD2 epitope. This population of cells (BSIL4/LD2) does not express the SSEA3 glycoconjugate and is largely nonpeptidergic. All four populations of sensory neurons (SP, CGRP, SSEA3, and LD2/BSIL4) can be infected by herpes simplex virus (HSV). However, the relative proportion of SSEA3- and LD2/BSIL4-labeled cells that were infected productively with HSV was much less than expected based on the relative size of the populations of these neurons in the ophthalmic region of the ganglion.

Localization of tumor necrosis factor receptor messenger RNA in normal and herpes simplex virus-infected mouse eyes.

PURPOSE: To investigate the distribution of p75 and p55 tumor necrosis factor receptor (TNFR) mRNA in normal mouse eyes and in mouse eyes acutely infected with McKrae strain herpes simplex virus (HSV). METHODS: In situ hybridization with antisense 35S-labeled riboprobes for p55 and p75 TNFR subtypes was used in uninfected and HSV-infected mouse eyes. Controls included the use of sense riboprobes and corneas inoculated with vehicle alone. RESULTS: In uninfected and infected mouse eyes, in situ hybridization produced an autoradiographic signal for mRNA, encoding both p75 and p55 over the corneal endothelium, iris, ciliary body, choroid, and arachnoid layers of the optic nerve sheath. In addition, the signal was observed over scattered cells at the vitreoretinal interface. Signal for p75, but not p55, was observed over cells in the retinal ganglion cell layer. Acute HSV infection was accompanied by an intense leukocytic infiltrate in the conjunctiva, the corneal subepithelium and stroma, the anterior and posterior chambers, the iris root and ciliary body, and the vitreous cavity. In this setting, increased p75 and p55 mRNA signal was correlated closely with the number and location of receptor-bearing white blood cells. Signal over control sections hybridized with sense p75 and p55 TNFR cRNA probes was comparable to background. Signal over control eyes inoculated with sterile vehicle showed slight increased signal in the immediate vicinity of the traumatic keratitis, but otherwise it was comparable to that observed in uninfected animals. CONCLUSIONS: The observed distribution of p75 and p55 TNFR mRNA in normal and acutely infected mouse eyes, and particularly over the heavily vascularized uveal tract and over cells at the vitreoretinal interface, supports a role for TNF as a mediator of intraocular inflammation, perhaps as a key regulator of the blood-ocular barrier.

Acquired immunodeficiency syndrome--associated herpes simplex virus retinitis. Clinical description and use of a polymerase chain reaction--based assay as a diagnostic tool.

OBJECTIVES: To describe 2 patients with acquired immunodeficiency syndrome who experienced a rapidly progressive, bilateral retinitis due to herpes simplex virus (HSV) (1 case due to HSV type 1 [HSV-1] and 1 case due to HSV type 2 [HSV-2] and to present a novel diagnostic polymerase chain reaction (PCR)-based assay. METHODS: The presentation, clinical course, and diagnostic PCR-based assay used to make the diagnosis of HSV retinitis in 2 patients with acquired immunodeficiency syndrome are described. RESULTS: Both patients experienced a rapidly progressive, bilateral retinal necrosis associated with intraretinal hemorrhages and a diffuse vasculitis. The PCR-based assays demonstrated HSV DNA in the vitreous specimens from the 2 patients. Restriction analysis on the amplified DNA showed HSV-1 in 1 patient and HSV-2 in the second patient. The diagnosis was supported in both patients by the occurrence of a herpes simplex-like encephalitis, and in 1 patient by a positive vitreous culture. The HSV-1-associated vasculitis affected primarily the retinal arterioles, with marked capillary dropout and occlusion of larger arcade vessels. In contrast, the HSV-2-associated vasculitis affected the retinal veins more than the arterioles, and was associated with an exudative retinal detachment. CONCLUSIONS: To our knowledge, these are the first 2 patients with acquired immunodeficiency syndrome in whom HSV has been implicated as the sole cause of a rapidly progressing, necrotizing retinitis. Combined PCR and restriction analysis of vitreous samples from such patients is a useful and highly specific means of diagnosing HSV-1 and HSV-2 retinitis.

Chronic varicella-zoster virus epithelial keratitis in patients with acquired immunodeficiency syndrome.

OBJECTIVE: To characterize further a chronic epithelial keratitis caused by varicella-zoster virus infection in patients with acquired immunodeficiency syndrome (AIDS). METHODS: Patients with AIDS and chronic epithelial keratitis associated with varicella-zoster virus from 3 institutions were identified. Patient records were reviewed retrospectively for the following data: medical and demographic characteristics, techniques of diagnosis, physical findings, course, response to treatment, and outcome. RESULTS: Sixteen patients were studied. CD4+ T-lymphocyte cell counts were available in 11 patients, with a median of 0.034 x 10(9)/L (range, 0-0.094 x 10(9)/L). Two patients had no history of a zosteriform rash. In the remaining patients, the interval between rash and keratitis ranged from 0 days to 6 years. In all cases, the keratitis was chronic and characterized by gray, elevated, dendriform epithelial lesions that stained variably with fluorescein and rose bengal. The peripheral and midperipheral cornea was most commonly affected, and, in 13 of the 16 patients, the lesions crossed the limbus. Pain was a prominent feature, occurring in 12 of 16 patients. In 9 of 12 patients tested, varicella-zoster virus was identified by culture, direct fluorescent antibody testing, polymerase chain reaction testing, or a combination of these studies, with direct fluorescent antibody testing (6 of 8 positive results) and polymerase chain reaction testing (3 of 3 positive results) appearing to be the most sensitive. Response to antiviral medication was variable. CONCLUSIONS: In patients with AIDS, varicella-zoster virus may cause a chronic infection of the corneal epithelium. The keratitis is characterized by dendriform lesions, prolonged course, and frequently by extreme pain. It can occur without an associated dermatitis.

Rate of anterograde axonal transport of [125I]wheat germ agglutinin from retina to optic tectum in the chick.

We have investigated the rate of anterograde axonal transport of affinity-purified [125I]wheat germ agglutinin (WGA) in chick retinal ganglion cells. By 2 lines of evidence, we found the rate to be 22-44 mm/day. This rate is slower than that reported for many other endogenously synthesized proteins or for horseradish peroxidase, the only other exogenously supplied protein studied as an anterograde transported marker. This difference in rate of transport of [125I]WGA may reflect a novel pathway important in membrane recycling.

Further evidence in support of the selective uptake and anterograde transport of [125I]wheat germ agglutinin by chick retinal ganglion cells.

Following intravitreal injection, affinity purified, iodinated wheat germ agglutinin ([125I]WGA) is taken up by chick retinal ganglion cells and transported in an anterograde direction to nerve terminals in the optic tectum. The accumulation of axonally transported label in the tectum may be measured quantitatively. Using such an approach, we find that co-injection of [125I]WGA with an excess of unlabeled WGA reduces the amount of axonally transported labeled lectin. Since co-injection of comparable levels of soybean agglutinin or Ulex Europeanus-I fails to reduce tectal labeling to a similar extent, and since native WGA at the same concentration does not appear to be toxic to retinal ganglion cells, these results support the hypothesis that the uptake and subsequent anterograde axonal transport of WGA by these cells is a selective process, dependent on a limited number of extra- or intracellular binding sites.

HSV (type 1) infection of the trigeminal complex.

Following corneal inoculation with herpes simplex virus (Type 1) (HSV), virus spreads to the CNS by axonal transport in the central branches of trigeminal ganglion cell neurons. Although this mode of viral entry to the CNS is rare for humans, it appears to be the principal route of entry into the CNS in animal models of herpetic corneal disease. In this study, the corneas of BALB/c mice were unilaterally inoculated with HSV, and the distribution of HSV-immunoreactive label was studied to identify the central branches of the axons of infected trigeminal ganglion cells. Virus was first noted in the brainstem trigeminal complex 4 days after corneal inoculation, when HSV-labeled afferents were found throughout the course of the descending tract of V as well as in interstitial neurons in the tract. By 5 days labeled neurons were also found not only in the n. caudalis and portions of the n. interpolaris of the trigeminal complex but also in laminae I-IV of the dorsal horn of the upper cervical levels of the spinal cord. No immunoreactivity was seen in other regions of the complex, including the n. oralis or the main sensory n. of V. By 6 days, however, the infection had spread to the main sensory division of V.

Distribution of tumor necrosis factor receptor messenger RNA in normal and herpes simplex virus infected trigeminal ganglia in the mouse.

PURPOSE: to investigate the distribution of p55 and p75 tumor necrosis factor (TNF) receptor mRNA in normal murine trigeminal ganglia, and in murine trigeminal ganglia acutely infected with McKrae strain herpes simplex virus (HSV). METHODS: in situ hybridization with antisense 35S-labeled riboprobes for mRNA encoding both the p55 and p75 TNF receptor (TNFR) subtypes was used in normal and HSV-infected murine trigeminal ganglia. Sense riboprobes were used as controls. RESULTS: in situ hybridization with both p55 and p75 riboprobes produced a strong autoradiographic signal over many, but not all, trigeminal sensory neurons. Signal for mRNA encoding both TNFR subtypes was also present over the arachnoid layers surrounding trigeminal ganglia. Acute ocular HSV infection was accompanied by an intense leukocytic infiltrate into the ophthalmic portion of the trigeminal ganglia, and, in this setting, increased p55 and p75 mRNA signal was closely related to the location and number of infiltrating white blood cells. The distribution and number of trigeminal sensory neurons expressing mRNA for the two TNFR subtypes did not appear to change following infection. Signal over control sections hybridized with sense p55 and p75 TNFR cRNA probes was comparable to background. CONCLUSIONS: the observed distribution of p55 and p75 TNFR mRNA over trigeminal sensory neurons and over the arachnoid layers surrounding trigeminal ganglia supports suggestions that TNF has a direct effect on neurons, either as a neuromodulator or neurotrophic factor, and that TNF may play a central role in blood-brain barrier regulation. Increased signal for TNFR mRNA in acutely infected trigeminal ganglia appears to reflect infiltration by receptor-bearing white blood cells.

Treatment of ocular disease in eczema herpeticum.

Individuals with atopic dermatitis are particularly susceptible to herpes simplex viral infection and may develop dissemination (eczema herpeticum). Additionally, they may develop severe and bilateral herpetic ocular disease. The keratitis is commonly complicated by stromal scarring and slow epithelial healing despite topical antiviral therapy. We treated three patients who had herpetic keratoconjunctivitis associated with eczema herpeticum. In all three cases the keratitis resolved promptly (48 to 72 hours) without residual scarring after treatment with systemic acyclovir and topical trifluridine. The combined use of systemic acyclovir and topical trifluridine may be of similar value in treating all cases of atopic herpetic keratitis.

Conjunctival lymphocytic nodule associated with the Epstein-Barr virus.

Infection with Epstein-Barr virus has been reported to have numerous systemic and ocular manifestations. In this study, a 38-year-old man with acute infectious mononucleosis was examined for a painless left red eye of three days' duration. The patient had a two-week history of fatigue, low-grade fever, sore throat, and lymphadenopathy. Serologic evaluation was indicative of an acute primary infection with Epstein-Barr virus. A large, salmon-colored, supranasal bulbar conjunctival mass was observed in the left eye. No associated conjunctivitis was present. Biopsy of the conjunctival lesion disclosed a dense leukocytic infiltrate, which consisted primarily of mature lymphocytes and plasma cells. Immunocytochemical evaluation of the tissue with monoclonal antisera disclosed Epstein-Barr latent membrane protein and nuclear protein 2 in a small fraction of the cells constituting the infiltrate. The conjunctival infiltrate resolved completely within one month, paralleling the regression of the patient's lymphadenopathy.

Disciform keratitis: a case of herpes zoster sine herpete.

PURPOSE: To describe a case of disciform keratitis in a patient with acquired immunodeficiency syndrome (AIDS) in which varicella-zoster virus was the causative agent. METHOD: Case report, Polymerase chain reaction-based assays for varicella-zoster virus, cytomegalovirus, and herpes simplex virus were used to analyze an aqueous aspirate. RESULTS: We examined a 41-year-old man with AIDS but without a history of varicella-zoster virus dermatitis who had disciform corneal edema in his left eye. Varicella-zoster virus was detected by a polymerase chain reaction-based assay in the aqueous of the left eye; however, neither cytomegalovirus nor herpes simplex virus DNA were detected by polymerase chain reaction-based assays. The corneal edema slowly resolved while the patient was treated with famciclovir. CONCLUSION: Varicella-zoster virus may cause disciform keratitis without a preceding skin eruption.

Cytomegalovirus-associated acute retinal necrosis syndrome.

PURPOSE: To describe a case of acute retinal necrosis syndrome in which a polymerase chain reaction-based assay provided evidence for cytomegalovirus as the causative agent of the syndrome. METHODS: Polymerase chain reaction-based assays were used to analyze a vitreous aspirate from a 70-year-old man with acute retinal necrosis syndrome. The specimen was tested for cytomegalovirus, varicella-zoster virus, and herpes simplex virus type 1 and type 2. RESULTS: The polymerase chain reaction assay for cytomegalovirus was positive, and polymerase chain reaction assays for varicella-zoster virus and herpes simplex virus type 1 and type 2 were negative. CONCLUSION: Cytomegalovirus may be a causative agent of acute retinal necrosis syndrome.

Identification of bacterial pathogens in patients with endophthalmitis by 16S ribosomal DNA typing.

PURPOSE: To determine whether sequence analysis of 16S ribosomal DNA (rDNA) can be used to detect bacterial pathogens in patients with postoperative endophthalmitis. METHODS: In 10 eyes of 10 patients, vitreous specimens were collected for culture and rDNA typing. Variable segments of each ribosomal DNA specimen were amplified by polymerase chain reaction (PCR), sequenced, and aligned by BLAST, a computer alignment program, against sequences in GenBank at the National Institutes of Health. RESULTS: Specimens were available from five eyes with bacterial endophthalmitis diagnosed by Gram stain or culture. Amplified 16s rDNA sequences from the eyes of three patients were identical to microbiologic results. Polymerase chain reaction results were negative in two cases in which unusual organisms were detected. All five control specimens from patients with nonbacterial endophthalmitis or uveitis were PCR negative. Approximately 48 to 72 hours are required under ideal conditions for final species identification with this ribosomal typing technique. CONCLUSIONS: 16S rDNA typing shows potential as a relatively rapid technique for identifying bacteria in vitreous samples.

Cataract surgery with ciliary sulcus fixation of intraocular lenses in patients with uveitis.

PURPOSE: To describe intentional placement of intraocular lens haptics in the ciliary sulcus of patients with uveitis who are at high risk for postoperative posterior synechiae and lens dislocation. METHODS: We reviewed our experience with 16 eyes of 12 patients with uveitis who underwent cataract surgery with ciliary sulcus fixation of intraocular lenses. Patients were followed for a median of 16.5 months (range, 9 to 44 months) after surgery. We evaluated eyes for surgical technique and the following preoperative and postoperative factors: best-corrected visual acuity, intraocular pressure, anterior chamber cells, and posterior synechiae. The following additional postoperative factors were sought: lens dislocation, lens edge capture, and evidence of pigment dispersion. RESULTS: Posterior synechiae were present in 13 eyes before surgery; postoperative posterior synechiae developed in only three of these eyes. These adhesions resulted in lens edge capture in one eye and limited lens decentration in another. Scant pigment was present on the lens optic or in the anterior chamber, suggesting pigment dispersion, in four eyes. We found no evidence of consistently increased anterior segment inflammation or intraocular pressure after surgery when compared with preoperative levels for this group of patients. Postoperative posterior synechiae were seen more often in eyes that had can-opener anterior capsulotomy than in eyes that had continuous, curvilinear capsulorhexis (P = .036). CONCLUSIONS: Ciliary sulcus fixation allows the intraocular lens to serve as a physical barrier between the iris and the lens capsule remnants. This technique may be useful for reducing the risk of postoperative posterior synechiae in patients with uveitis without increasing the risk of other postoperative problems.

Ocular and sinus microsporidial infection cured with systemic albendazole.

PURPOSE: To report treatment of a patient with acquired immunodeficiency syndrome (AIDS) and ocular and paranasal sinus microsporidial infection. METHOD: Case report. RESULTS: A patient with AIDS and ocular microsporidial infection experienced resolution of ocular symptoms with topical fumagillin, but symptoms recurred upon cessation of therapy. Paranasal sinus microsporidial infection was diagnosed. The patient received sequential systemic treatment with itraconazole followed by albendazole. Sinus symptoms resolved with albendazole. He remained symptom-free with a normal examination 17 months after concluding therapy. CONCLUSIONS: Although fumagillin and itraconazole may have played a role, systemic albendazole appears to be responsible for clinical resolution of microsporidial infection.

Nocardia scleritis.

PURPOSE: To describe a case of Nocardia scleritis, an unusual ocular infection. METHODS: Case report and review of pertinent literature. RESULTS: An 83-year-old man with leukocytoclastic vasculitis was initially examined for infectious necrotizing scleritis after explantation of an extruded scleral buckle. The patient was successfully treated with sulfonamides. CONCLUSIONS: Nocardia asteroides may cause infectious scleritis in the absence of cataract surgery or trauma. Treatment with sulfonamides can result in a satisfactory outcome.

Viral causes of the acute retinal necrosis syndrome.

PURPOSE: The primary goal of this study was to determine the viral cause of the acute retinal necrosis syndrome in 28 patients (30 eyes). A secondary goal was to investigate possible associations between viral cause and patient age, and viral cause and central nervous system disease. METHODS: A retrospective case series in which we reviewed the laboratory results and clinical histories of 28 patients (30 eyes) diagnosed with acute retinal necrosis syndrome, from whom vitreous or aqueous specimens were received, for diagnostic evaluation using previously described polymerase chain reaction-based assays. RESULTS: Varicella-zoster virus, herpes simplex virus, and cytomegalovirus (CMV) DNA were detected in aqueous and/or vitreous specimens from 27 of 28 patients (29 of 30 eyes with a clinical history of acute retinal necrosis syndrome). No sample was positive for DNA from more than one virus. Varicella-zoster virus DNA was detected in 13 patients (15 eyes). Median age was 57 years. Herpes simplex virus type 1 DNA was detected in seven patients (seven eyes). Median age was 47 years. Six of these patients had a history of herpes simplex virus encephalitis. Herpes simplex virus type 2 DNA was detected in six patients (six eyes). Median age was 20 years. Three of these patients had a likely history of meningitis. Cytomegalovirus DNA was detected in one patient who was immunosuppressed iatrogenically. No viral DNA was detected in one patient from whom a sample was taken after 6 weeks of acyclovir therapy. CONCLUSIONS: The data suggest that varicella-zoster virus or herpes simplex virus type 1 cause acute retinal necrosis syndrome in patients older than 25 years, whereas herpes simplex virus type 2 causes acute retinal necrosis in patients younger than 25 years. A history of central nervous system infection in a patient with acute retinal necrosis syndrome suggests that herpes simplex virus is likely to be the viral cause.

Microsporidial keratoconjunctivitis in a patient without human immunodeficiency virus infection.

PURPOSE: To describe a case of microsporidial keratoconjunctivitis in a patient without human immunodeficiency virus (HIV) infection. METHODS: Case report. An epithelial corneal scraping from a woman with chronic bilateral keratoconjunctivitis was evaluated by Giemsa stain. RESULTS: Giemsa stain of an epithelial corneal scraping disclosed intracellular and extracellular spores characteristic of microsporidia. An HIV enzyme-linked immunosorbent assay (ELISA) test was negative. The signs and symptoms of the bilateral keratoconjunctivitis resolved after treatment with albendazole. CONCLUSION: Microsporidia may cause a chronic epithelial keratoconjunctivitis in the absence of HIV infection.