Ophtalmologie : organe de la Societe francaise d'ophtalmologie最新文献

Pharmacological inhibition of capsule opacification e.g. using antimitotics such as daunomycin is a promising concept. Our own in vitro studies on cultured porcine lens epithelial cells have shown, that daunomycin penetrates the cells within at least 5 minutes. It possesses a low acute cytotoxicity and significantly inhibits epithelial cell proliferation at dose dependent concentrations ranging from 2.5 to 7.5 mg/l. In addition, in vitro studies on isolated pig corneas showed almost no corneal endothelial toxicity. After 10 resp. 30 min. exposure to 7.5 mg/l daunomycin, there was only 4.8 +/- 1.6 resp. 6.1 +/- 1.5% endothelial damage that dit not significantly differ from BSS serving as control. Encouraged by our clinical experience of good anterior segment tolerance of 7.5 mg/l daunomycin when used during vitrectomy in PVR, we started a prospective clinical trial to assess the effect to daunomycin on capsular opacification after ECCE with endo-capsular IOL implantation using the envelope technique. After agreement of the medical ethic commission we chose 6 patients with a mean age of 78 (72-83), no other ocular or general diseases and bilateral cataract of identical morphology and density. After written consent of the patients their first eye was operated using BSS as control. At least 4 weeks later the second eye was operated and received 0.5 ml of daunomycin (7.5 mg/l) applied during 5 minutes into the cleaned capsular bag, leaving the anterior capsular flap and a Healon filled anterior chamber to protect the surrounding intraocular structures. Mean postoperative control time actually is 12 (6-17) months for the controls and 10 (5-14) months for the eyes treated with daunomycin.(ABSTRACT TRUNCATED AT 250 WORDS)

Up to now EOG has been the only method used to record ocular movements in daily practice. However such a mean has various drawbacks and limits. It has two main gaps: firstly for vertical movements because the interference discharges related with palpebral movements and blinkings; on the other hand for oblique movements because the unequal transmission of EOG potential towards the orbital rim. The differential photo-oculography perfected by Charlier et Buquet has been fitted and now can be easily used in clinical conditions. With this optical method, it exists a direct relation between the gaze direction and video signals of the eye. The authors point out the reliability of its results not only for horizontal movements, but also for vertical and oblique movements. This method allows a relevant analysis of all kinetic parameters whatever the moving axis may be.

An experimental model was developed to study the permeability of individual retinal vessels in vitro using microperfusion techniques adapted from the kidney tubule studies. Inulin was used as the reference tracer and D-glucose as the test tracer. We found a concentration dependent flux of D-glucose from lumen to bath that increased as D-glucose concentrations in the lumen rose. The flattening of the hyperbolic curve at the higher D-glucose concentrations in the lumen appears consistent with the Michaelis-Menten equation (Km = 6 x 10(-3) M).

An instrumental setup has been developed in order to perform a quantitative clinical study of the reflectance of ocular tissues in several spectral ranges of the visible and the near infrared. The images recorded at different wavelengths are obtained nearly simultaneously from a CCD camera adapted to a retinal camera and connected to a microcomputer. The results of their analysis after processing are described. Each different type of lesion exhibits a typical spectral signature, demonstrating the value of this noninvasive extra ancillary test to help the differential diagnosis and the follow-up of choroidal tumors.

The authors suggest the production by the cultured RPE cell of one or more angiogenic substances. This activity is highly increased when RPE are cultured in poor conditions, either due to a poor medium or after having been challenged by a high number of rod outer segments. The mitotic factor appears heat-labile and trypsine sensitive, but not dialysable which suggest their biochemical nature to be a protein.

In situ hybridization of nucleic acid probes, encoding the key enzymes of the synthesis of neurotransmitters, with sections of retina is a new method giving complementary informations to the data obtained by immunocytochemistry and autoradiography. It will allow a better characterization of amacrin cells, whatever might be their type, and a refined understanding of their function. It is an accurate tool to investigate the mechanisms of retinal degenerations and spontaneous or experimental microphtalmia.

Macular drusen, hard or soft, have been often observed at the early stages of age-related macular degeneration. Clinically, it has been shown that soft drusen and macular subretinal new vessels are associated in a statistically significative manner. The question is to recognize and to determine drusen at greatest risk for developing choroidal neovascularization? To answer to this question, a method of digital images analysis of fluorescein angiography had been perfected. About ten eyes, preliminary results show, an objective and quantitative difference of the evolution of the grey level during the same angiogram between the different retinal structures. This method would bring a prognostic feature for the long term follow-up of patients with drusen.

An immunohistological study was performed in specimens of epiretinal membranes obtained during surgery in patients with proliferative diabetic retinopathy or retinal detachment with proliferative vitreoretinopathy. Using immunostaining procedures, these membranes were found to contain great amounts of immunoglobulins and complement, as well as a strong expression of class II antigens. These results confirm the involvement of auto-immune phenomena in intra-ocular proliferative diseases and the close relationship between the immune system and peptide growth factors.

From a KOS herpes simplex virus strain prepared in VERO cells we have been able to obtain after several exposures to increasing concentrations of trifluorothymidine, four resistant mutants. Among these strains, 31 T mutant was a TK-altered strain of low pathogenicity, sensible to acyclovir and did not induce recurrences. These properties might allow the use of such a strain as a living attenuated antiherpetic vaccine.

Composition of gas generated by the utilisation of Nd-Yag laser in eyes filled with silicone oil were studied by means of an in vitro optical breakdown in silicone oil. The newly formed gas were analysed by headspace gas chromatography on two separate columns. The secondary gas were mainly methane and ethylene which might be potentially harmful to the ocular tissues.