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Biomedical subjects

M Leys

Publications and source records attributed to M Leys.

16 recordsLinked to original sources

Progressive cone dystrophy and sensorineural hearing loss.

A 39-year old man presented 13 years ago with a history of progressive loss of vision and photophobia. A full ophthalmological and ENT work-up during several years of follow-up, including psychophysical as well as electrophysiological tests, revealed a progressive cone dystrophy in combination with sensorineural hearing loss. His younger sister presented with very similar features and underwent the same work-up. A novel syndrome of progressive cone dystrophy and sensorineural hearing loss is described in both siblings. Both also suffered from non-ocular disease possibly related to ciliary dysfunction. The condition is likely to be inherited as an autosomal recessive trait.

Adult↗

The effects of acetazolamide in albino rabbits, pigmented rabbits, and humans.

In three separate experiments albino rabbits, pigmented rabbits, and humans were tested following administration of acetazolamide and without acetazolamide. In all three experiments, we recorded electroretinograms (ERGs) under dark adapted and light adapted conditions and measured the b-wave amplitudes. Dark adapted ERG b-wave amplitudes were increased following administration of acetazolamide as compared to control conditions, in albino rabbits, pigmented rabbits and humans. Light adapted b-wave amplitudes showed no statistically significant changes as a function of acetazolamide administration although in all three experiments there was a trend toward light adapted b-wave amplitude reduction following administration of acetazolamide. In the human experiments, ERG a-wave amplitudes were also measured. Light adapted a-wave amplitudes were reduced following administration of acetazolamide. In the human experiments, several behavioral tests were performed, including L'Anthony desaturated D-15, Farnsworth-Munsell 100 hue, Cogan-Gunkel chromatograph, Nagel anomaloscope, Goldmann-Weekers dark adaptometry. There were no consistent changes in the human dark adaptation thresholds or color discrimination, although several measures approached significance.

Acetazolamide↗

X linked progressive cone dystrophy. Localisation of the gene locus to Xp21-p11.1 by linkage analysis.

Six affected males, three female carriers, and two possible carriers were evaluated from a three generation pedigree with X linked progressive cone dystrophy. The affected males presented with progressive decrease of visual acuity, impairment of colour vision, and deterioration of electroretinogram, which ranged from absent response to red light in all young patients to abnormal cone-rod responses in the elderly ones. In most affected males dark adaptation curves were monophasic and the electro-oculogram values were reduced. While some obligate carriers showed functional anomalies, they all had reduced electroretinogram response to red light. The a1/aT ratio for 1 joule white light was an appropriate indicator for carrier state. The family was studied with seven DNA markers from the proximal part of the short arm of the human X chromosome. So far, significant linkage has been found between three DNA markers and COD1, which assigns the progressive cone dystrophy gene (COD1) in this family to Xp21-p11.1. Differential diagnosis with congenital cone dystrophies is discussed.

Adult↗

Identification of a key recombinant which assigns the incomplete congenital stationary night blindness gene proximal to MAOB.

The gene for complete congenital stationary night blindness (CSNB1) has been assigned to the Xp11.3 region. However, little evidence has been provided for the assignment of the incomplete congenital stationary night blindness gene (CSNB2). Here we present the clinical and molecular data from a CSNB2 family which show a key recombinant assigning the CSNB2 gene proximal to MAOB.

Chromosome Mapping↗

Fundus changes in membranoproliferative glomerulonephritis type II. A fluorescein angiographic study of 23 patients.

A total of 23 patients aged between 11 and 64 years who had biopsy-proven membranoproliferative glomerulonephritis type II (dense deposit disease) were studied using fluorescein angiography of the retina. With the exception of two adolescents, all patients exhibited small subretinal nodules that were similar to basal laminar drusen. Subjects with a long history of renal disease displayed more numerous and larger nodules as well as atrophic changes. Four subjects presented with subretinal neovascular membranes.

Adolescent↗

Acute macular neuroretinopathy after shock.

Acute macular neuroretinopathy is a rare disease that has been described mainly in women taking hormonal contraceptives. An association either with a viral illness or with the parenteral use of sympathomimetics was sometimes found. We describe its occurrence in a 22-year-old female following an anaphylactic shock after a bee sting, and in a 26-year-old female following a pregnancy complicated with vena cava syndrome and delivery by caesarean section. A combination of factors including hypoperfusion, Valsalva stress, estrogen-induced hematological and rheological changes, and alpha-adrenergic stimulation apparently provoked this clinical manifestation.

Adult↗

Subretinal neovascular membranes associated with chronic membranoproliferative glomerulonephritis type II.

Subretinal neovascular membranes were observed in three patients with chronic membranoproliferative glomerulonephritis type II (dense deposit disease). The first signs of glomerulonephritis occurred at respective ages of 13, 10 and 10 years; subretinal neovascular membranes were noted at respective ages of 25, 32 and 32 years. All patients had bilateral, widespread retinal pigment epithelial abnormalities. Our findings indicate that subretinal neovascularization is a complication of dense deposit disease. In one patient, the early recognition and laser treatment of an extrafoveal subretinal neovascular membrane prevented further loss of vision.

Adolescent↗

Multiple evanescent white dot syndrome (MEWDS).

We describe the course of MEWDS (multiple evanescent white dot syndrome) in 2 young females. The first patient presented with a very pronounced macular edema. The second patient had merely optic disc edema. Both had an enlargement of the blind spot, which normalized later. Only the granular aspect of the fovea persisted in the involved eye.

Adult↗

Posterior microphthalmos.

Posterior microphthalmos is a congenital anomaly of the posterior segment of the eye, caused by an abnormally thickened sclera. The thickened sclera does not impede the growth of the neuro-retina but seems to influence the development of the choroid and of the retinal pigment epithelium. This may explain the common occurrence of a papillomacular fold in such cases. As such eyes are at risk of developing uveal effusion or angle-closure glaucoma, it is important to consider the diagnosis of posterior microphthalmos in high hypermetropic eyes.

Adult↗

The influence of oxybuprocaine (Novesine) on the intraocular pressure.

Patients with raised intraocular pressure often have lower tension during hospital admissions than on out-patient measurement, even though the therapy is the same. A prospective study on 18 volunteers and 10 glaucoma patients was set up to find out whether oxybuprocaine eyedrops or repeated applanation tonometry could have anything to do with this. The tension was measured at least 3 times a day with the non-contact tonometer (NCT). In the case of the volunteers oxybuprocaine was instilled into the eye 3 times a day for one week. In the case of the patients the tension in one eye was measured with the Goldmann tonometer on several days after the application of oxybuprocaine drops. No reduction in intraocular pressure was found during the observation period, nor was there an obvious difference between the test eyes and the control eyes. In hospital, patients had at 11 o'clock in the morning intraocular pressure which was on the average 2.2 +/- 1.5 mmHg lower than that measured at out-patient checks, in spite of receiving the same therapy.

Adult↗

Blue-yellow colour vision changes as early symptoms of ethambutol oculotoxicity.

To find out the most sensitive parameter of early toxic ocular changes, a group of patients was extensively examined at regular intervals during therapy with ethambutol. Colour vision abnormalities could be detected using the desaturated panel of Lanthony in the presence of normal visual acuity, normal visual fields, normal visual-evoked potentials and a normal panel D-15 test. Major blue-yellow errors were found in treated patients without visual complaints as well as in a group of healthy volunteers, but there was a significant difference between both groups. In a later stage of intoxication, blue defects, red-green defects or tritanomalous defects can be observed, together with other symptoms of ocular intoxication.

Adult↗

Sequential observation of fundus changes in patients with long standing membranoproliferative glomerulonephritis type II (MPGN type II).

Specific fundus changes have been reported in patients with membranoproliferative glomerulonephritis type II (MPGN type II). We studied the clinical course of this retinopathy in four patients who all had a long follow-up with several fundus examinations. Sequential observation was indicative of a slow progression of the retinopathy. Most eyes maintained in the chronic stages a nearly normal visual acuity, and a full visual field despite the existence of marked drusen and atrophic changes. The prognosis however must be somewhat guarded, since choroidal neovascularization developed in three eyes and caused bilateral severe visual loss in one patient.

Adult↗