Familial simple ectopia lentis: a case study.

Hereditary simple ectopia lentis affected nine patients in three generations of a family. Inheritance appeared to be autosomal dominant. Examination of 12 family members, employing body proportion measurements, chest x-ray, echocardiogram, and urinary cystine or blood methionine levels, revealed no evidence of any systemic disease. In all cases except two, lenses were bilaterally and superiorly dislocated. The degree of dislocation varied considerably among those affected, causing no visual disturbance in some and severely limiting visual acuity in others. Visual deficits were greatest in patients with intermediate degrees of dislocation. To date, the only known complications related to the dislocations have been two cases of bilateral cataracts. The indications for lensectomy in patients with ectopia lentis are reviewed.

Effects of alpha-aminoadipate isomers on the morphology of the isolated chick embryo retina.

The glutamate analogue, alpha-aminoadipate (alpha AA), was administered in the DL-, D-, and L-forms to chick embryo retinas in vitro. Two-hour incubation of retinas, with each form of alpha AA, resulted in glial swelling of progressive severity as the concentration of the adipate increased. Damage was most severe with the L-isomer, which produced a mixed glial-neuronal lesion that affected inner neuronal structures. The effect of the D,L racemic mixture was limited to glia and was less severe than damage seen with the L-isomer. The D-isomer produced effects similar to, but less severe than, those seen with the D,L mixture. Neuronal damage was seen subsequent to extensive Müller cell swelling in longterm cultures (24 hours) with the L- and DL-isomers. In contrast, the D-isomer did not produce discernible neurotoxicity even after a 24-hour treatment with 2.4 mM. Morphologic changes resulting from 2-hour adipate treatment were, to a large extent, reversible.

Age-dependent effects of glutamate on photoreceptor cells of the isolated chick embryo retina.

Neurotoxic and gliotoxic effects of glutamate were studied in isolated chick embryo retinas of various ages. Employing a short-term incubation system, we found that initial cellular changes in retinas from 15- and 21-day chick embryos were localized to glial Müller cells as previously shown in retinas from 12-day embryos. In the older retinas, however, an additional selective lesion was consistently found in the presumptive photoreceptor cells. Similar photoreceptor damage was not seen in 12-day retinas, even after treatment with relatively high glutamate doses. Autoradiographic uptake of tritiated glutamate in retinas at 12 and 14 days was localized to the glial Müller cells; in the 14-day retinas, however, there was also uptake of the labeled amino acid into the developing inner segments. Uptake of tritiated glutamate in retinas at younger (8-day) and older (21-day) ages did not show any obvious localization of the label.

Glutamate-induced cellular injury in isolated chick embryo retina: Müller cell localization of initial effects.

The neurotoxic and gliotoxic effects of glutamate and several glutamate analogues were studied in isolated chick embryo retinas. To facilitate examination of initial pathological events, a short-term incubation system was developed and used for light microscopic and autoradiographic investigation. Low-dose, short-term glutamate treatment of 12-day retinas resulted in a glial-specific lesion in the Müller cells, characterized by extensive cellular edema; at higher concentrations and/or longer treatment times, neurotoxic as well as gliotoxic effects were seen. The early glial damage was identical in appearance to that seen after incubation with DL-alpha-aminoadipate and other reported gliotoxins. No evidence of a similar glial-specific action was seen after administration of kainic acid, although extensive neuronal degeneration did result. Incubation of retinas with tritiated glutamate (3H-glu) revealed a selective uptake of the label by Müller cells. Autoradiographic grains were localized over Müller foot processes at the inner limiting membrane, and by 30 minutes labeled the entire glial system. Prior treatment with neurotoxic levels of glutamate did not alter the autoradiographic localization to glial cells. Possible glial-neuronal interactions and their effect on cytotoxic patterns are discussed.