Search

Purpose: New treatments against long-lasting uveitis need to be tested. Our aim was to develop a six-week model of uveitis in rabbits. Methods: Rabbits were presensitized with an s.c. injection of Mycobacterium tuberculosis H37RA emulsified with TiterMax® Gold adjuvant. Uveitis was induced at day 28 and 50, by intravitreal challenges of antigen suspension. Ocular inflammation was assessed till euthanasia at day 71 after s.c. injection of M. tuberculosis H37RA by: (a) the number of inflammatory cells in aqueous humor (AH); (b) the protein concentration in AH; (c) the clinical score (mean of conjunctival hyperaemia, conjunctival chemosis, oedema and secretion); (d) the microscopical score (mean presence of fibrin and synechiae, aqueous cell density and aqueous flare grade, as scored by slit lamp). Results: At the sites of presensitization injection, rabbits presented flat nodules which progressively vanished. The first challenge induced a significant increase in the four parameters ( p < 0.05 the Wilcoxon/Kruskal-Wallis test). The AH contained 764 ± 82 cells/µl and 32 ± 0.77 mg protein/ml. During the following days, inflammatory parameters decreased slightly. The second intravitreal challenge increased inflammation (3564 ± 228 cells/µl AH and 31 ± 1 mg protein/ml), which remained at a high level for a longer period of time. Conclusion: We developed a model of long-term uveitis, which could be maintained in rabbits for at least six weeks. Such a model could be used to test the efficacy of either new drugs or various drug delivery systems intended to deliver active agents during a few months. [ABSTRACT FROM AUTHOR]

Purpose: Necrotizing herpetic retinopathies (NHR), a new spectrum of diseases induced by viruses of the herpes family (herpes simplex virus, varicella-zoster virus and cytomegalovirus), includes acute retinal necrosis (ARN) occurring in apparently immunocompetent patients and progressive outer retinal necrosis (PORN) described in severely immuno-compromised patients. Signs of impaired cellular immunity were seen in 16% of ARN patients in a review of 216 reported cases, indicating that immune dysfunction is not only at the origin of PORN but might also be at the origin of ARN. The aim of this study was to correlate clinical findings in NHR patients with their immunologic parameters.Methods: Charts from patients with the diagnosis of ARN or PORN seen from 1990 to 1995 were reviewed. Clinical characteristics and disease patterns were correlated with immunological parameters taking into account CD4 lymphocyte rate in AIDS patients and blood-lymphocyte subpopulation determination by flow cytometry, cutaneous delayed type hypersensitivity testing and lymphocytic proliferation rate to seven antigens in HIV-negative patients.Results: During the period considered, 11 patients and 7 patients fulfilled the criteria of ARN and PORN respectively. Immune dysfunctions were identified in most patients. Mild type of ARN and classical ARN were associated with discrete immune dysfunctions, ARN with features of PORN was seen in more immunodepressed patients and classical PORN was always seen in severely immunodepressed HIV patients.Conclusion: Our findings suggest that NHR is a continuous spectrum of diseases induced by herpes viruses, whose clinical expression depends on the immune state of the host going from mild or classical ARN at one end in patients with non-detectable or slight immune dysfunction to PORN in severely immunodepressed patients at the other end and with intermediary forms between these extremes. [ABSTRACT FROM AUTHOR]

Purpose: To compare retinal arterio-venous circulation time by fluorescein (FA) and indocyanine green angiography (ICGA) in birdshot chorioretinopathy.Methods: We analyzed prolonged retinal arterio-venous fluorescein transit time, a known feature in birdshot chorioretinopathy and correlated it with ICGA findings in four consecutive patients.Results: Mean retinal arterio-venous fluorescein circulation time was 31.1 +/- 5.2 seconds, a transit time significantly longer than in a group of ten patients with sarcoidosis (9.45 +/- 3.36 sec., p < 0.0001) and in a group of three cases with Vogt-Koyanagi-Harada disease (7.0 +/- 1.1 sec., p < 0.0001).Conclusion: Prolonged fluorescein arterio-venous transit time seems to be a characteristic feature of birdshot chorioretinopathy that does however not reflect the actual intravascular hemodynamic situation but diffuse blood-retinal barrier damage allowing exudation, slow gradual tissue impregnation and delayed venous reabsorption of small molecules like fluorescein. [ABSTRACT FROM AUTHOR]

AIMS/BACKGROUND: The subcutaneous injection of bacterial endotoxin in Lewis rats produces an acute intraocular inflammation evolving over a 24 hour period. This endotoxin induced uveitis (EIU) is characterised by a biphasic protein exudation and a cellular infiltrate composed of macrophages and polymorphonuclear neutrophils (PMNs). This model was used to study the mechanism of cellular infiltration in ocular inflammation. METHODS: EIU was induced by a subcutaneous injection of lipopolysaccharide (LPS) (S typhimurium) at 350 micrograms/kg. The levels of cytokine induced neutrophil chemoattractant (CINC) were measured every 2 hours in the serum and in the aqueous humour by ELISA. The intraocular inflammation was quantified by protein measurement and leucocyte counting. RESULTS: The kinetics of CINC production in the systemic circulation showed a rapid rise, peaking 2 hours after LPS injection, followed by a progressive decline over the next 8 hours. In the eye, the CINC levels increased above the serum levels 10 hours after EIU induction corresponding to the time of cellular infiltration. When leucocyte entry in the eye was inhibited by 56% and 64% with an antiadhesion molecule antibody, there was only a slight reduction in the aqueous humour CINC levels of 9% and 16%, respectively, indicating that CINC was produced by ocular tissue cells. The specific effect of CINC in the eye was confirmed when a direct intraocular injection of 250 ng of purified CINC was followed by significant PMN infiltration, in the absence of protein exudation. CONCLUSION: The data indicate that the production of the CINC chemotactic factor by ocular tissue participates in the inflammatory reaction in EIU. [ABSTRACT FROM PUBLISHER]

Rifabutin is a semi-synthetic antimycobacterial agent mainly used in the treatment of Mycobacterium avium-complex (MAC) in AIDS patients. Rifabutin-induced anterior uveitis has been reported previously. We report the case of a rifabutin-induced cystoid macular oedema (CMO) in an immunocompetent patient with pulmonary MAC infection. As far as we know, CMO secondary to rifabutin therapy has not been described previously. [ABSTRACT FROM AUTHOR]

Corneal intraepithelial neoplasia (CIN) is a rare dysplastic process affecting mostly elderly fair-skinned people. A variant of the disease associated with contact lens wear was recently described. The three cases reported here had a history of contact lens wear together with strong ultraviolet light exposure. These two conditions may represent a serious risk factor for the development of CIN. [ABSTRACT FROM PUBLISHER]

Purpose To develop a long‐term experimental model of uveitis using a new easier method for animals. Methods A suspension of desiccated Mycobacterium tuberculosis H37RA was mixed with TiterMax® Gold Adjuvant to produce a water‐in‐oil emulsion. Pigmented rabbits were pre‐sensitized with a s.c. multisite injection (400 ul) of emulsion. Two challenges were performed by intravitreal injection of 100 ul of M. tuberculosis H37RA suspension, under systemic and topical anesthesia. Clinical examinations and aqueous humors punctures under systemic anesthesia were regularly performed till day 71. Hyperemia, chemosis, edema and secretion were clinically scored from 0 to 3. Ocular inflammation was assessed by: a) the clinical score mean (sum of individual scores divided by 4), b) the number of inflammatory cells in aqueous humor (AH) and c) the protein concentration in AH. Results Rabbits presented a nodule at the sites of pre‐sensitization injection. Clinical score of inflammation reached a maximum 3 days after the first intravitreal challenge. The AH contained 835 cells/ ul and protein concentration in AH was 30 mg /ml. During the following days, inflammatory cell number and protein concentration in AH significantly decreased, whereas the clinical score returned to zero. The second intravitreal challenge induced an inflammation; six days after this challenge, 3800 cells/ul and 30 mg of proteins /ml were counted in AH. Inflammation remained high to moderate over 21 days at least. Conclusion We developed a new model of experimental uveitis, whose schedule was simple. The use of TiterMax® Gold Adjuvant showed advantages over other adjuvants. And uveitis could be maintained during 21 days at least. [ABSTRACT FROM AUTHOR]

Purpose To describe angiographic patterns encountered in the context of ocular syphilis and to offer statistical associations between specific angiographic manifestations and severity of disease presentation as well as disease evolution after treatment. Methods We retrospectively reviewed the Fluorescein and ICG angiograms of 23 patients with ocular syphilis presented to the Uveitis clinic of the Jules‐Gonin Eye Hospital. FA and ICGA were performed following a standard protocol for posterior uveitis. Patterns of fluorescence were noted and subsequently statistical associations between each angiographic pattern and any demographic, clinical or laboratory parameter at baseline and after treatment were sought. Results Vasculitis in fluroangiography exhibited a statistically significant association with vitritis (p=0.020) and a borderline association with macular oedema (p=0.086). Disc hyperfluorescence in fluroangiography was significantly associated with seropositivity for HIV infection (p=0.012). The presence of any Dark Dots in ICGA significantly correlated with anterior uveitis (p=0.013) and marginally with vitritis (p=0.034) and relapse of inflammation after proper antibiotic treatment (p=0.066). An important association between the presence of Hot Spots on ICGA and longer duration of symptoms prior to initial visit was also identified (p=0.007). Conclusion Out of the several associations identified implicating specific angiographic features, we underline the possible predictive value of the presence of any Dark Dots in ICGA for future relapse of inflammation after treatment and the role of Hot Spots in ICGA as markers of long‐standing disease. [ABSTRACT FROM AUTHOR]