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Biomedical subjects

J Libert

Publications and source records attributed to J Libert.

At least 19 recordsLinked to original sources

Endogenous mycotic endophthalmitis in an infant.

We report a case of atypical bilateral endogenous mycotic endophthalmitis in an infant. A diagnostic vitrectomy was done on the left eye. Electron microscope examination of the vitreous demonstrated fungal mycelia. Intravenous treatment with amphotericin B seemed effective for treating the infection of the right eye, but a vitrectomy was necessary to prevent deprivation amblyopia and retinal traction, secondary to persistence of a dense vitreous membrane.

Amphotericin B

[Vitrectomy in uveitis].

Although its indications are relatively unfrequent, vitrectomy may be justified in certain types of uveitis. It allows differential diagnosis between vitreal inflammation and infection, accurate diagnosis in several metastatic conditions, Whipple disease with ocular involvement, amyloidosis and specific inflammations of various origin. If vitreous opacities become prominent or if retinal complications occur, therapeutic vitrectomy may be indicated without major risks. It will offer a marked improvement of the vision, an easier treatment for new inflammatory episodes and maybe a reduction of the activity of the inflammatory process.

Amyloidosis

[Prevention of bacterial infections using ciprofloxacin in granulocytopenic patients with cancer].

The optimal approach to reduce bacterial infections in granulocytopenic patients is still controversial. Recently, fluoroquinolones have been developed and real progress has been achieved in the prevention of Gram negative bacilli septicemia. This study reports our experience with ciprofloxacin and shows the excellent tolerance of ciprofloxacin by our patients as well as promising data for the reduction of Gram negative bacilli infection. However, practical modalities to prevent infection caused by Gram positive cocci remain to be defined.

Adolescent

Cyclosporine in Behçet's disease resistant to conventional therapy.

Cyclosporine (cyclosporine A) at 7 to 16 mg/kg/day was administered for eight to 18 months to four patients with Behçet's disease with bilateral panuveitis resistant to the combination of prednisone, colchicine, and chlorambucil. Visual acuity was maintained or improved in all eyes. Color vision also improved significantly. A dramatic and significant decrease of the chronic vitreous haze occurred within the first two weeks of therapy and persisted until the end of the study. Retinal inflammation, including hemorrhages, exudates, edema, and fluorangiographic abnormalities, decreased progressively in all eyes. The severity of the anterior and posterior acute attacks also decreased significantly. This study suggests that cyclosporine is beneficial for the treatment of refractory and severe Behçet's disease, but its side effects require careful follow-up.

Adult

Comparative toxicity of intravitreal aminoglycoside antibiotics.

We compared the toxicity of the aminoglycoside antibiotics (tobramycin, amikacin, netilmicin, and kanamycin) by ophthalmoscopy, light and electron microscopy, and electro-retinography after intravitreal injection in rabbits in doses ranging from 100 to 3,000 micrograms. The earliest manifestations of toxicity were confined to the outer retina with each drug, with lamellar lysosomal inclusions in the retinal pigment epithelium as the earliest finding. However, the aminoglycosides displayed marked differences in the threshold dose required to produce toxic reactions, permitting the following ordering of toxicity: (most toxic) gentamicin greater than netilmicin = tobramycin greater than amikacin = kanamycin (least toxic).

Amikacin

[Fucosidosis. Ocular ultrastructure].

An ultrastructural study of the eyes of a six year old girl affected with fucosidosis demonstrated widespread overloading of lysosomes with a fibrillo-granular material of variable density. Conjunctival and corneal epithelial cells, keratocytes, sclérocytes, fibroblasts, corneal endothelial cells, retinal ganglion cells, inner segments of photoreceptors as well as glial cells of the optic nerve were markedly involved by the storage process. On the contrary, the pigment epithelium of the retina, the ciliary body and the iris were unaffected. Membranous cytoplasmic bodies were only disclosed within Schwann cells of conjunctival and ciliary nerves. Particularly striking lesions were observed within the endothelial cells of capillaries and veins of the eyes, as well as in all tissues examined, like the liver, spleen, kidney, lung, brain and skin. On the contrary, artery walls remained intact. These lesions explain the development of retinal vascular tortuosities, conjunctival aneurisms and cutaneous angiomas that characterize the clinical picture of our patient and that are often described in fucosidosis. The massive overloading of retinal ganglion cells contrasts with the absence of a macular cherry-red spot in fucosidosis. The nature of the stored material is probably responsible for this apparent discrepancy. Indeed, ganglion cells contain membranous cytoplasmic bodies in all diseases with cherry-red spots, whereas only a fibrillo-granular material was disclosed in the present case.

Capillaries

Retinal toxicity of intravitreal gentamicin. An electron microscopic study.

Retinal ultrastructure was examined at various intervals following a single intravitreal injection of 100-4,000 micrograms of gentamicin in rabbit eyes. Three days after injections of 100-500 micrograms, numerous abnormal lamellar lysosomal inclusions were observed in the retinal pigment epithelium (RPE) and in macrophages in the subretinal space. These changes were typical of drug-induced lipid storage and were comparable to inclusions reported in kidney and other tissues as manifestations of gentamicin toxicity. One week after similar injections, focal areas of RPE necrosis and hyperplasia with disruption of outer segments appeared, but the inner segments and inner retina were intact. Doses of 800-4,000 micrograms produced a combined picture of RPE/macrophage lipidosis within the first 3 days, with increasing, superimposed, inner, retinal necrosis. This study provides the first evidence of lysosomal alterations in ocular tissues following the intravitreal injection of gentamicin and implicates the RPE as the primary site of observed toxicity.

Animals

Alterations in cultured fibroblasts of sibs with an infantile form of a free (unbound) sialic acid storage disorder.

Cultured fibroblasts from two sibs with generalized hypertonia, hepatosplenomegaly, and psychomotor retardation within the first year of life were found to have unusual morphologic features. When examined by phase microscopy, the unstained and unfixed cells contained a large number of vacuolated structures whose gross appearance resembled that of a honeycomb in the cell cytoplasm. Electron microscopy studies, following fixation, showed the "honeycombing" to be the result of numerous, closely packed, cytoplasmic, membrane-bound vacuoles. In some of these structures the remains of fibrilogranular material could be detected. Biochemical analysis of crude sonicates of these cells revealed increased levels (4--7 x N) of an acid soluble component that reacted with thiobarbituric acid. Analysis of trimethylsilyl derivatives of this material by gas liquid chromatography and mass spectrometry showed it to be indistinguishable from sialic acid (N-acetylneuraminic acid). Quantitation of this material from the cells of one of the sibs after isolation on a Dowex column yielded 39.8 nmoles of free (unbound) sialic acid per mg protein whereas normal fibroblasts had 1--2 nmoles per mg. Bound sialic acid levels were at the upper limits of normal (24.8 versus 11--23 nmoles per mg protein). The concentration of cytidine monophosphate-sialic acid was normal. After incubation of the patient's fibroblasts with [3H]-N-acetylmannosamine for 72 h, there was a 7-fold increase (compared to normal fibroblasts) in the amount of radioactivity in free sialic acid present in the acid soluble fraction. The amount of labeled, bound sialic acid in the acid-insoluble pool, however, was the same in both patient and control fibroblasts.

Carbohydrate Metabolism, Inborn Errors

Multiple sulphatase deficiency with early onset.

This male infant was first brought to attention in the neonatal period because he presented clinical and radiological evidence of multiple bone deformities. He was readmitted at 21/2 months for hydrocephaly, hepatosplenomegaly and poor somatic and psychomotor development. In addition, coarse facies, corneal opacities and stiff joints were noticed. Bone X-ray anomalies and vacuolized lymphocytes supported the clinical presumption of lysosomal storage disorder. The diagnosis of multiple sulphatase deficiency rests on the presence of MPS and sulphatides in the urine, the finding of a mixed storage process in conjunctival biopsy and the demonstration of deficiencies in arylsulphatases A, B, C, iduronate sulphatase and heparan sulphatase in serum, leukocytes and cultured fibroblasts.

Abnormalities, Multiple