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

Recent evidence suggests that TGF beta, a substance synthetized and released by Retinal Pigment Epithelial (RPE) cells, might play a role in fibrotic preretinal proliferation. We measured the concentration of this factor by radioreceptor assay in samples of vitreous obtained from 17 patients by vitrectomy. Seven had uncomplicated Retinal Detachment (RD) and 10 had either Proliferative Vitreoretinopathy (PVR) or Epimacular Membranes (EM). In the RD group, the mean concentration of TGF beta was 0.06 p mole/ml of vitreous, and in the PVR group, 0.21 p mole/ml. The total mitogenic activity of native vitreous and the amounts of a and b FGF in each sample were also measured, but were not different in the 2 groups. These results suggest that TGF beta is involved in the mechanism of excessive repair which characterises preretinal proliferation.

In the literature, curves based on the geometrical-optical (theoretical) formula and on regression formulas are established to show the superiority of a certain formula type in respect to the other formula type. Such curves are not based on the data of an individual eye needing an IOL implant, they are (more or less) mean value curves for a certain corneal curvatures and for a certain assumed postoperative position of an IOL. Due to the fact that Sanders, Retzlaff and Kraff suppose a normal corneal curvature, her curve for the theoretical formula gives in short eyes unrealistic and much too high values. A "more realistic" curve for the theoretical formula would be situated in the region of the so called "second generation formulas". All these mean value curves are unable to demonstrate the precision of IOL power formulas for the individual case. For the individual case refractive balances allow precise statements concerning the formulas and the measuring accuracy of the used a-scan. Refractive balances are the comparison of all preoperative data of an eye with all postoperative data including postoperative ultrasound measurings of the pseudophakic eye. Our results of 197 IOL implantations with refractive balances show the clinical precision of the theoretical formula. This is still valid in cases having unusual optical data, for example having short or long eye axes, having unusual corneal curvature or unusual IOL main plain position.

The authors report the different types of arterial vascularization and lacrimal gland innervation, noticed in 100 human orbits with arterial latex injected. The lacrimal artery may be unique, arising either from the ophtalmic artery, the most frequent case (vascularization of type I) or from the external carotid system (vascularization of type II): it is possible that 2 lacrimal arteries are simultaneously present, originating from the 2 carotid system (vascularization of type III). The lacrimal gland is innerved by the lacrimal nerve and by one or several nervous branches, originated from the maxillary nerve. 3 possibilities can be found: a zigomatic branch from the maxillary nerve makes a preglandular anastomosis with the lacrimal nerve; a real lacrimal loop, which may form either an intraglandular anastomosis or be completely independant of the lacrimal nerve. Sometimes, several zigomatic rami do exist. These different variations and their frequency are analyzed and referred to the literature.

Birds are an excellent material for the study of retinal adaptation. In this work, the purpose of the authors is to analyse differences between electroretinograms of species of diurnal habits (Falconiformes) and electroretinograms of species of nocturnal habits (Strigiformes). The same is done on histology material about the two types of retina. The electroretinography answers and the retina histology can be correlated with the different species habits.

The first part of this work deals with the various therapeutics with pituitary aims on ten patients with proliferative retinopathy. In the second part, the Growth Hormone involvement is considered, by the mean of IGF-I dosages in the serum and the vitreous of diabetic and non-diabetic patients. IGF-I is also sought in neovascular membranes by immunohistological methods. If radioimmunological dosages are negative, IGF-I deposits are found into new vessels wall. The significance of these immunohistological findings remains to be determined.

Kainic acid administered intravitreally induced mitogenic effects in the adult rat retina at doses ranging from 60 nm to 200 nm. Similar effects resulted from the injection of domoic acid at doses ranging from 20 nm to 400 nm, and ouabain. L-glutamate, N-methyl D-aspartate and quisqualate provoked similar cytotoxic effects, i.e., swelling and vasuolization of the outer plexiform, inner nuclear and inner plexiform layer, and cell pycnosis. The latter induced no mitoses. The use of Rompun ketamine as anesthetic blocked the mitogenic effects. The immunohistochemical labelling of both glial fibrillary acidic protein and S100 protein in the dividing cells and the location of dividing nuclei in the inner nuclear layer are arguments for their Müllerian nature. We suggest that the mitogenic effects could account for reactive gliosis observed in some clinical conditions.

Corneal endothelium is a target tissue for retinoids and epidermal growth factor (EGF). We report here that retinoic acid and its synthetic analog, CBS-211 A (10(-8)-10(-7) M), enhance the mitogenic effect of EGF on cultured bovine corneal endothelial cells (BCEC). Furthermore, retinoid treatment increases the EGF-binding capacity of BCEC. The addition of cycloheximide (0.5 micrograms/ml) to cultures simultaneously with retinoids suppressed the retinoid effect on EGF-binding. These results suggest that retinoids could induce the expression of EGF receptors on BCEC as an early event. This study demonstrates a cooperation between retinoids and EGF in corneal endothelium and suggests that retinoids could have a beneficial effect on this tissue repair in vivo.

The aim of this study is to examine the variation of HLA expression on organ-cultured human corneas. Using an indirect immunofluorescence technique and monoclonal antibodies anti-HLA-A, B, C and anti-HLA-DR histocompatibility antigens were detected. In fresh corneas class I antigens were detected on epithelium and stroma but not on endothelium. Class II antigens were not detected on any corneal layer but were present on Langerhans cells within epithelium and stroma. The expression of HLA-A, B, C antigens within the corneal epithelium and the corneal stroma was not altered by 28 days of organ culture. HLA-DR antigens were present on Langerhans cells on corneas that had been in organ culture up to 14 days (present 6/9). After 14-28 days in culture Langerhans cells were not found on most corneas (present 3/12). Corneal preservation in organ culture at 31 degrees C affects expression of HLA antigens particularly of HLA-DR antigens. Combination of HLA matching donor-recipient with an 10-15 days organ cultured corneal button in high-risk patients seems to be of interest.

Transretinal PO2 profiles were recorded during normoxia and hyperoxia in normal and ischemic retinal territories in anesthetized miniature pigs using double barrelled recess type microelectrodes. In normoxia and hyperoxia the PO2 in the normal territory decreased from the inner retina and the choroid towards the mid-retina, indicating that the choroid cannot supply O2 to the whole normal retina. Preretinal and transretinal PO2 measurements in ischemic territories following a laser occlusion of a retinal branch vein demonstrated that in normoxia the direction of PO2 gradients prevents O2 diffusing from the choroid to reach the inner retina. This explains why the ischemic territories are hypoxic. In the contrary, during hyperoxia the intraretinal PO2 gradient indicates an O2 flux from the choroid to the inner retina resulting to marked preretinal PO2 increase at the affected territories. We proposed the hypothesis that in the ischemic retinas the hyperoxia does not induce a rise of the O2 consumption of the outer retina. Hence hyperoxia could be a useful tool to restore the oxygenation of the inner hypoxic retinal layers.

Rabbit ciliary body has been irradiated by accelerated proton beam. 24 animals have received on 20 and 40% of the total surface of ciliary body 45 and 60 Gy. We could confirm the very good precision of proton beam irradiation. No complication was noticed on slit lamp examination. The light microscope examination revealed haemorrhages, lymphocytes, plasma cells and histiocytes infiltration, late fibrosis and severe capillary alterations. The electron microscope examination showed a frank difference of radiosensitivity of the epithelial layers and a presumed partial rupture of the blood-aqueous barrier.