F. Leger

Protein Aggregation in the Aging Retina

The age-related altered expression of neuron-related proteins as seen in other regions of the central nervous system is expected in the aging retina. Using immunohistochemical techniques, we characterized the distribution and aggregation of tau, &bgr;A4-amyloid, &agr;-synuclein, and ubiquitin in human retina obtained from 19 enucleated eyes of patients aged 49 to 87 years and correlated the findings with the ages. Using a phosphorylation-independent antibody, tau aggregates were observed within the cytoplasm of several photoreceptor cells, and there was a positive correlation between age and the number of tau-positive ganglionic cells. Tau deposits were immunonegative with a phosphorylation-dependent antibody. We did not observe &bgr;A4-amyloid in subretinal pigment epithelium deposits or in neuroepithelial layers. &agr;-Synuclein and ubiquitin inclusions were found in the inner nuclear layer, and there was colocalization of these proteins. The proportion of patients displaying such &agr;-synuclein and/or ubiquitin intracytoplasmic inclusions was significantly higher with aging. The presence of ubiquitin deposits within drusen was remarkable, but diffuse ubiquitin aggregates between the retinal pigment epithelium and Bruch membrane were also noticed. These results indicate that protein aggregation in the retina increases with aging and that tau, &agr;-synuclein, and ubiquitin should be the subjects of future investigations.

Avantages et inconvénients du microkératome laser femtoseconde

Laser in situ keratomileusis (LASIK) complications are mainly attributable to imperfect cutting with the mechanical microkeratome. The femtosecond laser is an important challenger because it can provide extremely precise cutting beginning at any corneal point. We analyze the potential of this new tool from the results reported in the literature. The optomechanical control of the impact position provides freer and more effective intrastromal cutting than the blade. The best cutting matrix is obtained with the postage stamp method. If the plasma quality is not perfectly under control, side effects such as tissue streaks and secondary ultraviolet radiations can be observed. For LASIK surgery, femtolaser cutting can offer greater safety, reproducibility, predictability and flexibility. The risk of incomplete or irregular cutting and the free cap risk are reduced. Striae, epithelial defects and interface deposits should be minimized. A better flap congruence can limit the risk of secondary displacement and epithelial ingrowth. The results of making thinner flaps should be more predictable. Other than the high cost of the procedure, laser cutting has very few disadvantages. In 1999, Intralase Corporation introduced the first femtolaser microkeratome on the American market. Approximately 120,000 intra-LASIK procedures have been carried out with fewer cutting complications than with the mechanic blade.

Corneal myxoma associated with keratoconus and Down's syndrome.

Purpose. Primary myxoma of the cornea is extremely rare. Until now, only four primary corneal myxomas were reported in the literature, whereas secondary involvement of the cornea by conjunctival and limbal tumors is much more common. Methods. We report an additional case in a 26-year-old woman with keratoconus and Downs syndrome. Excision of the corneal mass was performed by penetrating keratoplasty. Histochemical, immunohistochemistry, and ultrastructural studies were used to obtain a definitive diagnosis. Results. The tumor exhibited the characteristic histologic features of myxoma. The tumor cells showed immunoreactivity for vimentin but not for S-100 protein, epithelial membrane antigen, CAM 5.2, HHF-35, or muscle-specific actin. Ultrastructural features were fibroblast-like or stellate cells with cytoplasm containing abundant, rough reticulum and dilated cisternae. No recurrence was observed 36 months after penetrating keratoplasty. Conclusion. This is only the fifth report of such an occurrence. Although the coexistence of myxoma in Downs syndrome with keratoconus is described here for the first time, the differential diagnosis of apparently evident acute hydrops on clinical inspection should not rule out the possibility of a corneal myxoma. Histologic analysis should therefore be performed.

Effets tissulaires et mécaniques observés lors de l’expérimentation d’un microkératome laser femtoseconde pour la chirurgie réfractive cornéenne

Introduction Malgre les progres des microkeratomes mecaniques utilises en chirurgie refractive, la part des complications mecaniques lors de la decoupe des cornees reste encore non negligeable. Une decoupe par laser pourrait fiabiliser cette procedure. Le laser femtoseconde est, a ce jour, le seul candidat potentiel pour cette utilisation. Le but de cette etude est l’evaluation preliminaire d’un microkeratome femtoseconde pour la decoupe de cornees porcines ex vivo . Materiel et methodes Dans un premier temps, nous avons analyse les elements fondamentaux de l’interaction du rayonnement femtoseconde (fs) avec le stroma corneen, comprenant le volume des lesions tissulaires, le seuil de claquage optique du stroma et la selectivite soustractive du rayonnement. Dans un deuxieme temps, nous avons etudie la decoupe de capots corneens par le laser : les effets tissulaires collateraux et la rugosite des interfaces sont observes respectivement en histologie et en microscopie electronique a balayage. Resultats Les resultats montrent qu’avec le laser femtoseconde, les effets photoablatifs et photodisruptifs du rayonnement sont tres proches. Cette caracteristique est specifique des lasers photodisrupteurs a impulsions ultra-courtes (une fs = 10 −15 seconde) et autorise une grande precision chirurgicale. Le seuil de claquage optique du stroma porcin est evalue a 0,55 J/cm 2 . Les lesions tissulaires collaterales sont infra-micrometriques. La rugosite du lit des capots corneens est optimale pour la technique de decoupe en timbre-poste imposant des impacts jointifs, tres nombreux et de volume le plus spherique possible. Conclusion La photodisruption corneenne par laser femtoseconde est objectivement reproductible et d’une grande precision. Les parametres optomecaniques identifies demandent une grande maitrise technologique et un travail d’equipe de recherche tres specialisee.

Penetrating corneal transplant with inadvertent corneal button inversion

PURPOSE To report a penetrating corneal transplant in which there was inadvertent inversion of the corneal button. DESIGN Interventional case report. METHODS A 48-year-old man with lattice corneal dystrophy had a third penetrating keratoplasty in the right eye 3 years after the second procedure and 2 years following renal transplantation. RESULTS Histologic examination of the corneal button from the second penetrating keratoplasty disclosed inadvertent corneal graft inversion. Survival epithelium from the donor in the anterior chamber may be explained by the ocular anterior chamber-associated immune deviation or by the patients systemic cyclosporine A (CsA) treatment after renal transplantation. CONCLUSIONS Histologically proven corneal button inversion is a rare cause of corneal graft failure.

Orbital melanocytoma: Multimodal imaging and review of the literature

An 11-year-old female, without past medical history, was referred with a two years’ history of proptosis of her left eye and a superotemporal eyelid mass. Her best-corrected visual acuity was 20/20 and the clinical examination found a smooth tumor in front of the lacrimal area and leading to an eyeball infero-medial dystopia. Firstly, a Doppler-ultrasonography was performed and showed a vascular solid lesion. Secondly, a computed tomographic scan demonstrated a large solid hyperdense and well-circumscribed lesion in the right superior orbit, enhanced after intravenous injection of Iobitridol (Guerbet, France) causing a mass effect on the eyeball and repelling the orbital roof without osteolysis (Fig. 1A—B). Finally, a magnetic resonance imaging (MRI) was performed. The mass appeared hyper intense on T1-weighted images and iso intense on T2-weighted images (with few hypo intense areas) homogenously enhancement after gadolinium injection (gadoteric acid, Dotarem, Guerbet, France) and these results were confirmed by subtraction between T1-weighted images without and gadolinium injection (Fig. 1C—D). The preoperative diagnosis was intraorbital cavernoma. After multidisciplinary discussion, a surgical treatment with a complete excision was decided (Fig. 1E). There were no postoperative complications.

Primary diffuse leptomeningeal gliomatosis: do we miss the diagnosis?

Primary diffuse leptomeningeal gliomatosis (PDLG) is characterized by diffuse infiltration of the leptomeningeal space by neoplastic glial cells without evidence of intra-parenchymatous primary tumor. We report a case of PDLG in a 68-year-old man, who died 1 month after onset of symptoms. The diagnosis was made on autopsy data. We discuss the particularities of this entity, which is not registered in the WHO classification of tumors of the central nervous system (2016). In case of an unexplained inflammatory meningeal process and in the presence of atypical cells in the cerebrospinal fluid, PDLG needs to be considered. This diagnosis of PDLG has to be confirmed by meningeal imaging-guided biopsy, which must be repeated if necessary.
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535 Difficultés diagnostiques devant une kératite à Fusarium.sp

Introduction Confrontation des resultats cliniques, microbiologiques et microscopiques confocaux, chez un patient atteint d’une keratite infectieuse severe a Fusarium.sp, etiquetee initialement, a tort, « keratite amibienne ». Objectifs et Methodes Il s’agit d’un patient de 31 ans presentant, depuis deux mois, une keratite severe, d’evolution torpide. Le tableau associait initialement ulceration geographique, infiltrat diffus et keratonevrite. Malgre le traitement antiparasitaire entrepris (Chlorexidine, Desomedine), l’etat clinique s’est deteriore. Notre demarche diagnostique s’est appuyee sur l’aspect clinique, la microscopie confocale et les prelevements microbiologiques. Resultats L’interrogatoire nous orientait tout d’abord vers une keratite amibienne (port de lentilles de contact, regles d’hygiene non respectees). L’examen clinique initial retrouvait un patient tres algique, avec une acuite visuelle a 1/10 e P8. A la lampe a fente, on observait une lesion stromale centrale, heterogene, profonde, ulceree en surface, avec reaction endotheliale. La microscopie confocale retrouvait des kystes evocateurs d’amibes, de taille 50 μm. Un nouveau traitement antiparasitaire (PHMB, Propamidine) fut instaure. L’evolution se fera vers une necrose corneenne necessitant une greffe de cornee en urgence, avec analyse anatomopathologique. Les cultures microbiologiques isolerent Fusarium sp. Le traitement antifungique propose, Posaconazole per os et Natamycine topique, sera alors rapidement efficace. Discussion On note donc la discordance entre les aspects cliniques, microbiologiques et microscopiques confocaux. L’analyse microscopique apparait ici non fiable avec la presence de faux positifs de kyste amibien. Le diagnostic a pu etre retabli grâce aux analyses microbiologiques retrouvant l’agent infectieux responsable. Conclusion Malgre l’apport incontestable des nouvelles technologies diagnostiques non invasives, les prelevements microbiologiques restent un element essentiel et incontournable dans les cas difficiles.