Phasische und tonische Funktion der Augenmuskeln

Zusammenfassung Die Augenbewegungen von 3 Patienten mit totaler Lähmung eines R. internus oder eines R. externus wurden elektronystagmographisch untersucht. Das freibewegliche Auge führte Blickzielbewegungen im horizontalen Meridian aus. Am Partnerauge (mit dem gelähmten Muskel) zeigte sich dabei folgendes: Bei Sakkaden in der Wirkungsrichtung des gesunden Muskels ruckte das Auge mit einer Amplitude, die etwa dem geforderten Blicksprung entsprach. Nach dem Ruck sank das Auge aber wieder völlig oder teilweise in die Ausgangsstellung zurück. Die verbleibende Stellungsänderung war umso größer, je weiter die Sakkade im Wirkungsfeld des gesunden Muskels ausgeführt wurde. — Aufgrund der Befunde kann geschlossen werden, daß ein normaler Augenmuskel zur Beschleunigung des Bulbus im gesamten Blickfeld gebraucht wird. Zum Halten des Bulbus wird der Muskel dagegen nur dann benötigt, wenn der Bulbus in der Blickfeldhälfte steht, die seiner Wirkungsrichtung entspricht.

---

Phasic and tonic function of eye musclesSaccades in patients with oculomotor or abducens paralysis

Summary Bye movements in 3 patients with a complete paralysis of one of the horizontal eye muscles were studied. In these cases, all horizontal movements of the affected eye were due to the opposing, well functioning muscle. No reciprocal innervation changes had to be taken into account in the paralysed muscle. The eye with the paralysed muscle, i. e. the bad eye, was occluded, and the good eye had to perform horizontal saccades which were initiated from various positions in the horizontal plane and were aimed towards the working direction of the well functioning muscle of the bad eye. The response of the bad eye always began with a phasic jerk. After this jerk the eye receded to a new position with an exponential time course. The difference between the previous and the new steady position was regarded as the tonic response. The jerks of the bad eye were only a little short of the saccades of the good eye, regardless of the position of the eyes at saccade onset. The amount of change in the tonic position largely depended on the sector of the field of gaze in which the saccade of the good eye was performed. In the off-field of the bad eye's working muscle, the tonic response was negligible, in the on-field the tonic responce reached nearly normal amplitude. These results fit nicely to Collin's measurements of in situ tendon forces in freely moving eyes and allow some inferences to be drawn as to the division of labour in the agonist and antagonist. The main task of the agonist in its off-field is to accelerate the globe during saccades. The ensuing new position is held predominantly by relaxation of the antagonist. In its on-field, the agonist is important for both, holding eccentric eye position as well as acceleration during saccades.

---

---

Mit Unterstützung der Deutsehen Forschungsgemeinschaft SFB 70, B4.     

The effect of argon laser trabeculoplasty on the blood-aqueous barrier and intraocular pressure in human glaucomatous eyes treated with diclofenac 0.1%

Background: We studied the effect of argon laser trabeculoplasty (ALT) on the bloodaqueous barrier (BAB) in 41 eyes of 41 patients with primary open-angle glaucoma, pseudoexfoliation glaucoma, or pigment dispersion glaucoma using the Fluorotron Master II. Methods: Fluorophotometry was performed the day before ALT and on the 3rd day after surgery at 30 and 60 min after intravenous injection of 7 mg/kg body weight sodium fluorescein 10%. Intraocular pressure (IOP) was measured using Goldmann applanation tonometry on the day before surgery and at 3rd days and 1 year (mean) after ALT. Patients were treated with argon laser by one surgeon (180°, 0.1 s, 50 m 0.6–1.0 W 56 laser burns). Eyes were randomly assigned to either diclofenac-sodium 0.1 % eye drops or vehicle. Eye drops were applied six times 1 h before ALT into the operated eyes and five times daily for 3 days postoperatively. Results: On the 3rd day after ALT there was significant disruption of the BAB in the placebo-treated eyes compared to the diclofenac 0.1%-treated eyes. In the placebo-treated eyes as well as in diclofenac-sodium 0.1 %-treated eyes there was a significant decrease of IOP postoperatively for up to 1 year. There was no significant difference concerning the IOP reduction after 1 year. Diclofenac-sodium 0.1 % eye drops significantly stabilized the BAB on the 3rd day after ALT, compared to placebo, in this model. Conclusion: Diclofenac-sodium 0.1 % significantly stabilized the disruption of the blood-aqueous barrier on the 3rd day after ALT. Concerning the IOP-lowering effect of ALT, the postoperative application of steroids should be avoided.     

Fibroblast growth factor 2, heparin and suramin reduce epithelial ulcer development in experimental HSV-1 keratitis

Background: We have previously shown that basic fibroblast growth factor (FGF-2) enhances corneal epithelial healing in different experimental models in vivo. In order to study the healing effect of this growth factor in pathological conditions of the cornea, we investigated whether topical application of FGF-2 could affect herpes keratitis in rabbits. Since HSV-1 infection is prevented in vitro by incubation with heparin, we also topically applied heparin and suramin, considering the similar interaction of herpes simplex virus and FGF-2 with cell membrane-anchored heparan sulfate. Methods: After virus inoculation with a human BEY.2 strain, rabbits were treated with either FGF-2 (200 ng to 2 g/application), heparin (250 g/application) or suramin (250 g/application) 4 times daily until day 14. Acyclovir and placebo administrations served as controls (n=48 rabbits). Computerized ulcer surface analysis, clinical observations and virus recovery assays were performed. Results: Topical FGF-2, heparin and suramin treatment revealed a significant reduction in peak ulcer sizes, and complete epithelial healing was achieved earlier than in placebo-treated corneas. However, no significant antiviral effect of FGF-2, heparin and suramin was detectable in plaque assays from conjunctival swabs. Conclusions: These experiments demonstrate that FGF-2 is effective in promoting herpetic epithelial ulcer healing, either due to its proliferative effects on epithelial cells or indirectly by occupying the sites on cell surface heparan sulfate necessary for the attachment of the virion. The latter mechanism of action is presumably the reason for the similar effect of heparin and suramin.     

Tierexperimentelle Untersuchungen zur Bestimmung der Dauer der „mechanisch-effektiven Periode“ des Muskelfasermembranaktionspotentials und der „elektro-mechanischen Latenzzeit“ der „fast fibres“ äußerer Augenmuskeln bei Kaninchen in vivo

Zusammenfassung Es wird über tierexperimentelle Untersuchungen zur Bestimmung der Dauer der mechanisch-effektiven Periode des Muskelfasermembranaktionspotentials und der elektro-mechanischen Latenzzeit von fast fibres äußerer Augenmuskeln bei Kaninchen in vivo berichtet.Die Untersuchungen wurden mit einer international standardisierten Glasmikroelektrodentechnik durchgeführt. Die statistische Auswertung basiert auf 250 Einzelregistrierungen in Superpositionstechnik.Den Mittelwert der mechanisch-effektiven Periode des Muskelfasermembranaktionspotentials bestimmten wir mit ¯x=0,52 ms, Standardabweichung s=0,08 ms. Die Vertrauensgrenzen lagen bei 99 % statistischer Sicherheit bei 0,43 ms und bei 0,55 ms. Nach diesen Untersuchungen beträgt die Dauer der mechanisch-effektiven Periode der fast fibres äußerer Augenmuskeln nur 1/3 der mechanisch-effektiven Periode der vergleichbaren Skelettmuskeln.Der Mittelwert der Dauer der elektro-mechanischen Latenzzeit der fast fibres wurde mit ¯x=1,97 ms berechnet, Standardabweichung s=0,30 ms. Die Vertrauensgrenzen lagen bei 99 % statistischer Sicherheit bei 1,86 ms und 2,08 ms. Die elektromechanische Latenzzeit der fast fibres äußerer Augenmuskeln ist also wesentlich geringer als die vergleichbarer Skelettmuskeln, sie liegt unter der 50 %-Grenze der elektro-mechanischen Latenzzeit der analogen Skelettmuskulatur.Durch diese Untersuchungen konnten die wichtigsten elektrophysiologischen Parameter bestimmt werden, die den Grenzwert der maximalen Geschwindigkeit einer Blickrichtungsänderung bedingen.

---

Animal experimental investigations for determining the duration of the mechanical-effective period of muscle action potentials and of the electro-mechanical latency period of fast fibres of external ocular muscles

Summary A report is given of an animal experimental study for determination of the duration of the mechanical effective period of the muscle fiber membrane action potential and the electromechanical latency period of fast fibers of the external ocular muscles in rabbits in vivo.The studies were carried out with an internationally standardized glass micro-electrode technique. The statistical values are based on 250 tests employing the superposition technique.The mean mechanical effective period of the muscular fiber membrane action potential was determined with SE=0.52 ms, SD=0.08 ms. The confidence thresholds were 99% statistically reliable with 0.43 ms and 0.55 ms. According to these studies, the duration of the mechanical effective period of the fast fibers of the external ocular muscles was only one-third off the mechanical effective period of the skeletal muscles.The mean duration of the electromechanical fast-fiber latency period was calculated with SE=1.97 ms, SD=0.30 ms. The confidence threshold was 99% statistically reliable with 1.86 ms and 2.08 ms. The electromechanical latency period of the fast fibers of the external ocular muscles was therefore significantly less than the skeletal muscles, lying under the 50% limit of the electromechanical latency period of the analogous skeletal musculature.These studies permit determination of the most important electrophysiological parameters which define a threshold value of maximal speed in vision direction changes.

---

---

Die experimentellen Untersuchungen wurden im Physiologischen Institut der Martin-Luther-Universität Halle mit Unterstützung durch Herrn Dr. rer. nat. H. Opitz durchgeführt, damaliger Direktor: Prof. Dr. med. habil. B. Lueken     

Mediators of the ocular inflammatory response to interleukin-1β plus tumor necrosis factor-α

Background: Intravitreal injection of marginally inflammatory doses of interleukin-1 and tumor necrosis factor- (IL-1 /TNF) has been shown to produce intraocular inflammation distinctly different from that induced by higher intravitreal doses of either IL-1 or TNF. Since cyclooxygenase inhibitors and platelet-activating factor (PAF)-receptor antagonists can reduce IL-1- or TNF-induced uveitis, the present investigation was undertaken to determine whether cyclooxygenase metabolites of arachidonic acid and PAF are important mediators of IL-1/TNF-induced uveitis. Methods: The cyclooxygenase inhibitor indomethacin and two structurally dissimilar PAF-receptor antagonists, SRI 63-441 and WEB 2086, were used to investigate the importance of cyclooxygenase metabolites and PAF in IL-1/TNF-induced uveitis. Results: Based upon the effectiveness of indomethacin, the anterior uveitis induced by IL-1/TNF could be divided into two phases; a primary phase dependent upon generation of cyclooxygenase metabolites (the first 24 h) and a secondary phase largely independent of cyclooxygenase metabolite production (24–48 h). Posterior uveitis was also apparent at 48 h and was reduced by indomethacin. SRI 63-441 reduced the anterior uveitis at 24 h and to a lesser extent at 48 h; it also reduced the posterior uveitis at 48 h. However, although WEB 2086 was as effective as SRI 63-441 in reducing PAF-induced platelet aggregation, ex vivo, it did not significantly reduce IL-1/TNF-induced uveitis. Conclusions: Although the findings do not support an important role for PAF in TNFa/IL-1-induced uveitis, it cannot be ruled out that more intensive treatment with a specific and long-acting PAF-receptor antagonist might yield more positive results.     

Toxicity of 1-(β-d-arabinofuranosyl)cytosine after intravitreal injection in the rabbit eye

The retinal toxicity of intravitreally injected 1-(-d-arabinofuranosyl)cytosine (cytarabine) was examined in 7 chinchilla rabbits to determine if cytarabine can be used as local therapy for vitreoretinal non-Hodgkin's lymphoma. Fractionated dose of 600 g, 1500 g, and 2700 g cytarabine in stabilized saline were given intravitreally in one eye (2 × 300 g, 5 × 300 g, and 3 × 900 g, respectively, with an interval time of 24 h) and stabilized saline in the other eye as control. Toxic effects were evaluated with biomicroscopy, direct ophthalmoscopy, fluorophotometry, electroretinography, light, and electron microscopy. Toxic effects were found with the 1500 g and 2700 g doses only. They consisted of a temporary impairment of the blood retina barrier function for fluorescein as measured by fluorophotometry and an irreversible change of the b-wave in the electroretinograms. No histopathologic changes were seen under the light microscope. Electron microscopic examination showed aberrations in the synaptic pedicles of the photoreceptor cells at a dose of 1500 g cytarabine. The results suggest that the cytarabine dose that is expected to be therapeutic for vitreoretinal non-Hodgkin's lymphoma (about 90 g given in three doses of 30 g) is non-toxic for ocular structures.Correspondence to: J.A. van Best     

Altersveränderungen kollagener Fasern der Aderhaut

Zusammenfassung Es wurden die Veränderungen der kollagenen Fasern der Aderhaut in verschiedenen Lebensaltern polarisationsoptisch untersucht. Die Menge ihrer fibrillären Elemente nimmt mit fortschreitenden Lebensjahren zu, die Grundsubstanz dagegen ab. Zwischen dem jugendlichen und älteren Kollagen ist ein struktureller Unterschied nachzuweisen. Die zart aufgebauten kollagenen Fasern der jugendlichen Chorioidea können als Porokollagen, die dicht strukturierten älteren Fasern als Stenokollagen aufgefaßt werden.

---

Summary The alterations of the collagenic fibres of different age in the choroid membrane were investigated by the polarisation-optic method. The quantity of fibrillar elements was found to increase in connection with age, whereas those of matrix to decrease. Structural differences have been shown between the young and the elder collagens. The collagenic fibres in a young choroid have a loose structure named porocollagen, whereas the old collagen has a solid one, the so-called stenocollagen.

     

Conjunctival tissue examination in severe eye burns: a study with scanning electron microscopy and energy-dispersive X-ray analysis

Background: Longlasting inflammation is a major problem in treatment after severe eye burns and may find expression in an altered elemental composition of the conjunctiva. Particulate contamination of biological tissue induces such inflammatory processes. In the anterior eye segment, trauma or subsequent therapy may give rise to such contamination. Scanning electron microscopy and energy-dispersive X-ray analysis are able to detect traumatic residues of submicron size and changes of the elemental composition.Methods: Conjunctival specimens from first-time peridectomy of three healthy and nine severely burnt-eyes were examined with scanning electron microscopy and energy-dispersive X-ray analysis. The samples were prepared as cryo- or paraffin sections, mounted on carbon blocks and coated with evaporated elemental carbon.Results: The samples of healthy conjunctiva showed higher concentrations of Na, P and CI. These elements showed lower concentrations in conjunctival stroma of burnt eyes excised before the 20th day after trauma than in material obtained subsequently. In two burnt conjunctival specimens there was severe traumatic contamination with Ca in Ca(OH)₂ and CaO burns, and in one case the traumatic substance was Si, in a peroxide plus silicone spray burn. In the remaining six cases, particulate contamination with Fe, Al, Ni, Zn, Cu, Ti and other substances was present in the burnt conjunctivas, while no contamination was detected in the specimens of healthy conjunctivas.Conclusions: The origin of the contaminant particles is assumed to be the trauma itself and the subsequent therapy. These investigations stress the importance, for clinical purposes, or early peridectomy and contamination-free therapy.     

Characterisation of the neovascularisation process in diabetic retinopathy by means of fractal geometry: diagnostic implications

The neovascularisation formation and regression process of the peripheral retina in diabetic retinopathy was studied by means of fractal analysis. The fractal dimension of the local retinal vessel pattern was calculated to be significantly lower before formation of relevant neovascularisations than 2.5 years later, after formation of strong preretinal neovascularisations. Another year later the new vessels had regressed partially and the fractal dimension was again significantly reduced. This behaviour is almost independent of the representation of the vessel thickness during calculation. Since the retinal vasculature is a fractal, the fractal dimension appears as the natural measure of proliferative retinal vessel changes. It is demonstrated that the fractal dimension can be applied to characterise proliferative diabetic retinopathy. These features offer the possibility for computer-driven (automated) quantitative characterisation of the treatment effect in proliferative diabetic retinopathy and possibly automated detection of proliferative diabetic retinopathy in the future. The limitations of the method are discussed.A preliminary report of this work was presented at the 33rd Meeting of the Association for Eye Research, Aachen, Germany, 10–13 June, 1992     

Frequency and amplitude in scotopically stimulated optokinetic nystagmus

Background: It was previously shown that optokinetic nystagmus (OKN) gain (eye velocity/target velocity) increases with increasing target luminance at a constant target velocity during scotopic vision. Eye velocity was defined as the amplitude of the eye jerk divided by the period time. The dependence of frequency and amplitude of eye jerks in scotopic OKN on target luminance and velocity was investigated in the present study Method: A total of nine subjects were examined for OKN with various target luminance and velocities under scotopic conditions. Monocular OKN was elicited by a vertical grating projected in a hemisphere. The eye movement was recorded by DC EOG Results: It was found that when a constant target velocity is used, both the frequency and amplitude of eye jerks increase with an exponential decline as target luminance increases. The maximum frequency and amplitude obtained at high target luminance are independent of target velocity. The exponential decline constants for both frequency and amplitude decrease with increased target velocity Conclusion: Both frequency and amplitude of eye jerks are responsible for changes in OKN gain when target luminance and velocity change.     

Immune response to intraocular injection of retinal S-antigen in adjuvant

It has been proposed that the introduction of foreign material into the eye at the moment of a penetrating trauma provides an adjuvant effect which, coupled with the release of antigen, might be responsible for sensitizing the immune system to produce a contralateral sympathetic ophthalmia. We addressed that hypothesis by injecting S-antigen with complete Freund's adjuvant (CFA) into the anterior chamber (AC) of the eye of Lewis rats. The injection of an identical dose of antigen (30 g S-Ag in CFA in a total volume of 10 l) via the foodpad (FP) or under the conjunctiva (SC) could induce typical experimental autoimmune uveitis (EAU). By immunizing via the AC route, we could demonstrate a positive sensitization of the immune system, manifested by serum antibody production against S-Ag and by the presence of S-Ag-specific, responsive T-lymphocytes in the spleen. However, immunization via the AC route did not induce contralateral uveitis, and the animals did not produce a DTH skin response when challenged intradermally with S-Ag as they did after FP immunization. In the light of these results, we evaluated the possibility that a DTH suppressive response was elicited by intracameral (IC) injection as seen in anterior chamber-associated immune deviation (ACAID): we tested the effect of splenectomy and cyclophosphamide pretreatment before IC immunization and the effect of secondary footpad immunization as well as T-helper cell transfer after IC immunization. The results given by these approaches argue against the induction of suppressor cells by IC immunization. We believe that the absence of lymphatic drainage from the interior of the eye is probably responsible for the absence of EAU induction through the IC route and that extrusion of the antigen under the conjunctiva might be required for the activation of EAU effector cells.     

Morphological changes in “Dry eye syndrome”

The authors present the pathologic changes of the conjunctiva in dry eye syndrome. They state that stratification of the epithelial cells and microplicae, change in the goblet cell population, and inflammation of the basal tissue cannot be regarded as characteristic symptoms.

---

Zusammenfassung Die Autoren berichten über die Bindehautveränderungen beim trockenen Auge Syndrom. Sie stellen fest, daß die Abflachung der Epithelzellen und Mikroplicae, eine Veränderung der Zahl der Becherzellen und die Entzündung des subepithelialen Gewebes nicht für charakteristische Symptome gehalten werden können.

     

Adult-onset foveomacular vitelliform dystrophy and indocyanine green videoangiography

Background Adult-onset foveomacular vitelliform dystrophy (AOFVD) represents a heterogeneous group of disorders with different clinical, angiography, and histopathological features. The most common form is characterized by a yellow, round to oval subretinal macular lesion with or without central pigmented spot. Methods Eight patients affected by typical AOFVD underwent fluorescein an giography and indocyanine green videoangiography (ICGV). Results Fluorescein angiography showed a central hypofluorescent spot surrounded by an irregular hyperfluorescentring ICGV demonstrated a foveal nonfluorescent spot, visible during the entire examination, and a hyperfluorescent area surrounding the central spot, which became evident soon after the beginning of the examination. Conclusions In light of previous histopathological studies, the central nonfluorescent spot may be interpreted as a masking effect of a pigment clump, whereas the hyper-fluorescent area may represent dye pooling or staining of the subretinal pigment epithelial material.     

Apparent cleavage of the retinal nerve fiber layer in asymptomatic eyes with high myopia

The appearance of the retinal nerve fiber layer was studied in one eye of 203 normal Asians (59 with high myopia – 5 D, and 144 with emmetropia or hyperopia). Cleavage of the retinal nerve fiber layer was observed in 3 of these 59 highly myopic eyes, but there was no significant damage to either the retinal pigment epithelium or the choroid. In contrast, no cleavage was observed in the other 144 emmetropic or hyperopic eyes. High myopia (P=0.0237, Fisher's exact test) was a significant risk factor for cleavage development in the retinal nerve fiber layer. The occurrence of a defect (nerve fiber loss) in the retinal nerve fiber layer in severe myopia (5/59, 8%) was also greater than that in either emmetropia or hyperopia (2/144, 1 %; P= 0.0229). These results indicate that subtle changes can occur in the appearance of the retinal nerve fiber layer of the eye in some patients with asymptomatic myopia.Correspondence to: E. ChiharaThis study was supported by grant-in-aid B-02454403 for Scientific Research from the Ministry of Education, Science and Culture of the Japanese Government     

Ocular findings in cystic fibrosis patients receiving vitamin A supplementation

Background: Vitamin A deficiency with eye symptoms has been reported in patients with cystic fibrosis who received the recommended daily intake of vitamin A. Methods: We measured serum retinol, dark adaptation, contrast sensitivity, and dry eye status in 35 adult cystic fibrosis patients to ascertain whether they had ocular signs or symptons. Results: Median serum retinol concentration was 1.95 mol/l, range 1.08–4.01 mol/l, with no values indicating vitamin A deficiency. Retinal light sensitivity was normal. Nineteen patients had reduced contrast sensitivity. Conjunctival imprints all showed plenty of goblet cells, but were characteristic of dry eye in 42% of patients (n=14). Decreased tear film stability was found in 49% (n=17), tear production was low in 31% (n=11), and 23% (n=8) showed an increased amount of dying epithelial cells. Nine patients (26%) had keratocon-junctivitis sicca according to the Copenhagen criteria. Conclusion: Our patients had no biochemical or clinical signs of vitamin A deficiency. We speculate that the high incidence of dry eye could be a primary manifestation of cystic fibrosis.     

Integrins in human anterior chamber angle

Background: Integrins, which are composed of an and subunit, are capable of binding to a number of extracellular matrix proteins and, hence, affect cell adhesion and proliferation.Methods: The distribution of the integrin (₁, ₃-₅) and (_1–6 and _v) subunits in human anterior chamber angle was studied in eyes from subjects aged 9 months to 81 years using the indirect immunofluorescence technique.Results: Immunoreaction for the ₁ subunit was found throughout the trabecular meshwork (TM), in the cribriform layer, and in the endothelial lining of Schlemm's canal (SC). Labelling for the ₃ subunit was found in the TM and the cribriform layer only. In infant eyes the ₅ subunit was present in all three areas with the highest concentration in the cribriform layer, whereas no reaction was observed in adult eyes. The ₆ subunit was localized to the endothelium of SC only. Immunoreaction for the _v subunit was present in the TM and the cribriform layer of infants and young adults.Conclusion: The present results suggest the presence of several integrin heterodimers, acting as potential receptors for laminin, collagen, fibronectin, and vitronectin, in the anterior chamber angle.     

Expression of mRNA coding for TNFα, IL-1β and IL-6 by cells infiltrating retinal membranes

Background: Cellular mechanisms of inflammation are thought to be involved in the pathogenesis of proliferative vitreoretinopathy, and cytokines, which are products of cell activation, are known to play an important role in the development and maintainance of inflammatory reactions. It was the aim of this work to investigate the presence of cells expressing cytokine mRNA within retinal membranes. Methods The presence of mRNA coding for the cytokines interleukin 1 (IL-1), interleukin 6 (IL-6) and tumour necrosis factor (TNF) was investigated in 19 epiretinal membranes obtained from eyes undergoing vitrectomy for the treatment of retinal detachment complicated by proliferative vitreoretinopathy. Results Cells expressing mRNA for IL-1 were observed in 7 membranes, cells positive for IL-6 mRNA were seen in 12 membranes, and cells exhibiting mRNA for TNF were present in 9 specimens. Only three membranes contained cells expressing mRNA for all the cytokines investigated. Four membranes possessed positive cells for IL-6 and TNF, two contained cells expressing mRNA for IL-6 and IL-1, and two others exhibited cells expressing mRNA for TNF and IL-1. Five membranes contained IL-6 mRNA-positive cells only, whilst two exhibited cells expressing mRNA for IL-1, or TNF only. Conclusion The present findings indicate that cellular activation may occur during the development of PVR, and suggest that these cytokines may be locally produced by cells infiltrating epiretinal membranes. The presence of IL-1, IL-6 and TNF mRNA-positive cells within retinal membranes provides further evidence of a pathogenic role of these cytokines in proliferative vitreoretinopathy.     

Cytotoxic effects of antiproliferative agents on human retinal glial cells in vitro

Purpose: Proliferative vitreoretinopathy (PVR) is characterizedby the formation of cellular membranes on the detached retina and also in the vitreous. Glial cellscan be found in epiretinal and subretinal membranes from eyes with PVR, proliferative diabeticretinopathy (PDR), idiopathic macular pucker, uveitis and other diseases affecting theretina. Proliferation and contraction of glial cells appears to play a role in the pathogenesisof PVR. This study is designed to inspect the effectiveness of harringtonine, as well as colchicine,daunomycin and fluorouracil, against cellular proliferation of cultured human retinal glial cellsthat might be involved in the retinal and/or vitreous proliferation. Methods: Cultures of human retinal glial cells were preparedusing the enzyme digesting method. Cells that had been in culture for 2–5 passages were usedin this study. Harringtonine (0.063 g/ml 2.0 g/ml), colchicines(0.5 g/ml 16.0 g/ml), daunomycin (0.1 g/ml 3.2 g/ml) and 5-fluorouracil(0.5 g/ml 16.0 g/ml) were added to cultures of human retinal glial cellsand the proliferation rates of the cells were measured by the MTT method. Results: Harringtonine at the dosage of 0.063 g/mlinduced suppression of cellular growth, but the changes were not statistically significant (p > 0.05).At a dosage ranging from 0.125 g/ml to 2.0 g/ml, harringtonine significantly suppressedcellular growth according to the test (p < 0.01). Likewise, other antiproliferativeagents inhibited cellular growth significantly at a dosage from 1.0 g/ml to 16.0 g/ml(colchicine), 0.2 g/ml to 3.2 g/ml (daunomycin) and 1.0 g/ml to 16.0 g/ml(5-fluorouracil), but not at 0.5 g/ml (colchicine), 0.1 g/ml (daunomycin) and0.5 g/ml (5-fluorouracil). The ID₅₀ were 0.33 g/ml (harringtonine), 3.11 g/ml (colchicine), 0.79 g/ml (daunomycin) and 5.23 g/ml (5-fluorouracil), respectively.Conclusions: Harringtonine was extremely effective ininhibiting human retinal glial cell proliferation, like other antiproliferative drugs such as colchicine,daunomycin and 5-fluorouracil. Harringtonine, therefore, may be a candidate for further studies regardingthe treatment of experimental PVR.     

The spectrum of eye disease in children with AIDS due to vertically transmitted HIV disease: Clinical findings, virology and recommendations for surveillance

Background: Eye disease in children infected with HIV is uncommon, but there is little information on which children require screening or surveillance and the management of those with retinitis. Methods: We examined 12 children with symptomatic HIV disease (of a cohort of 98 HIV-positive children) using indirect ophthalmoscopy. When retinitis was found it was documented photographically at the time of diagnosis and on follow-up. Results: Four cases of infective retinitis were diagnosed: three with probable cytomegalo-virus retinitis and one with progressive outer retinal necrosis. Conclusion: Detection of reactivation is difficult and we recommend fundus photography under general anaesthesia wherever possible. Children with other end-organ disease, symptomatic eye disease and advanced HIV disease with severe immunosuppression require ophthalmological surveillance.     

The effect of chemical stability and purification of perfluorocarbon liquids in experimental extended-term vitreous substitution

Background: To determine the importance of chemical stability and purification of perfluorocarbon liquids (PFCLs) in experimental retinal tolerance, we tested four different substances as long-term vitreous tamponade: purified and nonpurified perfluorodecalin (PFD) and perfluoro-octylbromide (PFOB) Method: After mechanical vitrectomy we replaced the vitreous of 65 rabbit eyes. Five groups were formed; four of them received the four PFCLs, while one served as control and received Ringer solution. The eyes were observed clinically every week and examined histologically after 1, 2, 4 and 8 weeks Results: After 1 week we observed foam cells and intraretinal macrophages in all eyes with PFCLs. Purified PFD caused retinal lesions in the photoreceptor, ganglion cell and outer nuclear layers after only 2 weeks in the lower part of the eyes. In eyes filled with purified PFOB we observed more pronounced damage of the same nature. Unpurified substances caused severe inflammation and retinal detachment Conclusion: Our study demonstrates that purification and chemical stability are important factors in retinal tolerance of PFCLs for vitreous replacement. Although purified PFD was tolerated by the rabbit eyes for 1 week, we cannot recommend this substance for short-term clinical use as a vitreous substitute.