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Biomedical subjects

N Ohba

Publications and source records attributed to N Ohba.

At least 127 records · Page 7Linked to original sources
PubMed1987

Specialization of the interphotoreceptor matrices around cone and rod photoreceptor cells in the monkey retina, as revealed by lectin cytochemistry.

The binding sites of two lectins, peanut agglutinin (PNA) and wheat germ agglutinin (WGA), in the interphotoreceptor matrix (IPM) and photoreceptor plasma membranes of the Japanese monkey (Macaca fuscata) retina were localized using a pre-embedding staining method with ferritin-conjugated (Fer) lectins as well as a postembedding staining method with fluorescence-labeled (FITC) lectins. FITC-PNA, but not WGA, stained cylindrical domains of the IPM around cone outer and inner segments, while the IPM around rods stained with FITC-WGA but not PNA. When the intact (not detached) retinal tissues were incubated with Fer-lectin, the lectin generally labeled neither the IPM nor photoreceptor plasma membranes, but labeled only those structures in detached portions occurring at the edges of occasional retinal tissue blocks. Thus, the neural retinas physically isolated from the retinal pigment epithelium (RPE) were utilized principally here. Ultrastructurally, the IPM in the intact retina consisted of granular and filamentous materials; the IPM in the isolated neutral retina also retained those components, although somewhat loosely organized, and the IPM around cones appeared to be preserved better than did the IPM around rods. Fer-PNA bound to the IPM associated with cones, but not rods; Fer-WGA bound to the rod- but not cone-associated IPM. The ferritin particles were found to lie close to the granular and filamentous materials. Those photoreceptor-associated IPMs extended to the apical surface of the RPE in detached portions or to the apical villi of the RPE which were frequently found in the isolated neural retinas. Also, Fer-PNA labeled the cone, but not rod, plasma membranes; Fer-WGA bound heavily to the plasma membranes of rod and cone outer segments, but sparsely to those of their inner segments. These results suggest that the IPM comprises chemically and physically differential domains specialized for cone and rod photoreceptor cells, and that these specialized IPM are structurally so stable that may be involved in isolating photoreceptor cells physicochemically from each other and in the interactions between the photoreceptors and the RPE, such as retinal adhesion.

Animals↗
PubMed1987

Leber's hereditary optic neuropathy: mitochondrial and biochemical studies on muscle biopsies.

Two patients with Leber's hereditary optic neuropathy underwent morphological and biochemical investigations of muscle biopsy samples from the biceps brachii. Although clinically there was no muscle weakness or atrophy, specific histochemical and electron microscopic examinations showed mild but distinct myopathic changes, including abnormal oxidative enzyme activities, aggregates of enlarged mitochondria in the subsarcolemmal regions, and disruptions of myofilaments. Biochemical analyses of mitochondria isolated from muscle samples did not show and deficiency in respiratory-chain enzyme complexes or defect in content of cytochromes. Leber's hereditary optic neuropathy is assumed to be a multisystem disorder involving skeletal muscle also.

Adolescent↗
PubMed1987

Waardenburg syndrome: a variant with neurological involvement.

A case of a variant of Waardenburg syndrome is reported. A 13-year-old boy with features of Waardenburg syndrome consisting of facial anomalies, heterochromia of the iris and fundus, and congenital sensorineural deafness had a marked mental and motor retardation and developed severe gait disturbance associated with neurological abnormalities including dystonia, muscular stiffness and peripheral neuropathy. Sural nerve biopsy revealed 'onion bulb' formation.

Abnormalities, Multiple↗
PubMed1987

Capsaicin-induced corneal lesions in mice and the effects of chemical sympathectomy.

Effects of chemical sympathectomy on corneal changes induced in mice by a s.c. injection of capsaicin were investigated. Pretreatment with a s.c. injection of 6-hydroxydopamine (6-OHDA) on the 1st and 2nd postnatal day or on the 14th and 15th postnatal day led to a marked suppression of the capsaicin-induced corneal lesions. This suppressive effect also was evident in case of administration after capsaicin treatment. Intraventricular injection of 6-OHDA had a slight, transient effect. DSP4 [N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine], another potent substance used for sympathetic denervation, had a suppressive effect similar to that of 6-OHDA. The concentration of capsaicin in tissues of the head was unaltered with 6-OHDA. The content of substance P (SP) in the ocular anterior segments was decreased, dose-dependently, with capsaicin administration. Neonatal administration of 6-OHDA decreased the rate of capsaicin-induced reduction of SP. However, this effect of 6-OHDA was too slight to explain the suppression of the corneal lesions, as the intensity score of lesions with a large dose of capsaicin after 6-OHDA was lower than that with a small dose of capsaicin without 6-OHDA, whereas SP content in the former was still much lower than that in the latter. On the other hand, the content of norepinephrine in the ocular tissues was decreased in the presence of 6-OHDA but not capsaicin. These results suggest that the corneal changes induced by capsaicin are largely inhibited by a decreased activity in the peripheral sympathetic system.

Animals↗
PubMed1987

Capsaicin-induced corneal changes associated with sensory denervation in neonatal rat.

A single subcutaneous injection of capsaicin (50 mg/kg) to neonatal Wistar rats induced prominent corneal changes consisting of initial edematous lesions and late degenerative opacities in the epithelium and stroma, with disintegrated epithelial cells on histologic sections. Qualitative and quantitative analyses of the corneal nerves by means of gold chloride impregnation revealed a marked degeneration of the intraepithelial terminal fibers, resulting in a significant decrease in neural density by over 70% of the normal value at 4 and 6 weeks after neonatal capsaicin treatment. Thereafter, regeneration of nerve fibers occurred, but the neural density did not return to the normal level at 6 months after treatment.

Animals↗
PubMed1986

Recovery of differential light sensitivity following surgery for rhegmatogenous retinal detachment.

Sixteen patients with phakic, nontraumatic rhegmatogenous retinal detachment were used in a prospective study on the change of the visual field following surgical treatment of the disease. The differential light threshold was measured across the visual field before and after surgery up to 1 year by means of the Octopus automated static perimeter. The visual sensitivity recovered prominently in the initial one to two months, followed by a slight improvement for up to a year. The final prognosis of visual sensitivity was correlated with the duration of detachment, but not with its extent or height. The recovery in the peripheral visual field was less remarkable, with residual slight defect. There was more improvement in visual sensitivity at the fovea than in visual acuity.

Adult↗
PubMed1986

Ultrastructural localization of lectin receptors in the monkey retinal photoreceptors and pigment epithelium: application of lectin-gold complexes on thin sections.

The cell surface and intracellular binding sites of two lectins, wheat germ agglutinin (WGA) and Ricinus communis agglutinin-1 (RCA-1), in the monkey retina were investigated at the ultrastructural level by means of post-embedding staining of Lowicryl K4M-embedded specimens with lectin-colloidal gold complexes. Effects of pretreatment with neuraminidase were also studied. The techniques enabled us to detect lectin binding sites in the various intracellular compartments of photoreceptor cells, retinal pigment epithelium (RPE), and interphotoreceptor matrices. Wheat germ agglutinin, which recognizes N-acetylglucosamine and sialic-acid residues, showed a prominent and uniform binding to the disc membranes of rod outer segments (ROS), rod connecting cilia, interphotoreceptor matrices, and RPE microvilli. The intensity of these binding sites was markedly reduced when thin sections were pretreated with neuraminidase, except the labeling of ROS disc membranes. Cones were labeled sparsely. The staining of phagosomes in the RPE cytoplasm did not change after neuraminidase digestion. RCA-1, which recognizes galactose residues, revealed a moderate binding to the ROS disc membranes, with a noticeably greater intensity of binding to the basal region of ROS disc membranes. With neuraminidase treatment heavier binding with RCA-1 occurred in interphotoreceptor matrices, connecting cilia and RPE microvilli, whereas there was no significant alteration in binding to the ROS disc membranes. Phagosomes in the RPE were also labeled with this lectin. The results suggest the presence of sialic acid and galactose as the constituent carbohydrates of glycoconjugates in the interphotoreceptor matrices and RPE microvilli.

Animals↗
PubMed1986

Two-dimensional gel electrophoretic analysis of lectin receptors in the bovine interphotoreceptor matrix.

Proteins and glycoproteins of the bovine interphotoreceptor matrix (IPM) with or without neuraminidase treatment was analysed by two-dimensional gel electrophoresis combined with Western blotting and staining with seven horseradish peroxidase-labeled lectins. More than 80 spots of proteins and glycoproteins were revealed on the gel. Nineteen spots (or groups of spots) were revealed by staining with five lectins [concanavalin A, wheat germ agglutinin (WGA), peanut agglutinin (PNA), Ricinus communis agglutinin-1 (RCA-1) and soybean agglutinin (SBA)]; some of those spots were specific for one lectin and others reacted with several lectins. We could not detect distinct spots reacting with Dolichos biflorus agglutinin or Ulex europaeus agglutinin-1. Neuraminidase digestions of the IPM increased and unmasked the binding spots for PNA, RCA-1 and SBA. The spots of WGA-receptors without neuraminidase treatment were mostly identical to the receptors for PNA, RCA-1 and SBA, which became prominent after the digestion. Spots reacting with RCA-1 were mostly identical to the spots of SBA-receptors. The spots reacting with PNA coincided only partially with the spots reacting with RCA-1 and SBA.

Animals↗
PubMed1986

Primary vitreoretinal dysplasia resembling Norrie's disease in a female: association with X autosome chromosomal translocation.

A female infant with the typical clinical and histopathological features of vitreoretinal dysplasia is described. She had an apparently balanced reciprocal chromosomal translocation 46XX,t(X;10) with the X chromosome breakpoint being on the short arm. Since the parents' karyotypes were normal, it is most plausible that a de novo chromosomal translocation disrupted the vitreoretinal dysplasia gene itself. The severe clinical symptoms of this heterozygous female patient were explained by non-random X inactivation. She may have had Norrie's disease, an X linked recessive disorder due to an X autosome translocation.

Female↗
PubMed1986

Acute posterior multifocal placoid pigment epitheliopathy associated with diffuse retinal vasculitis and late haemorrhagic macular detachment.

A 20-year-old healthy man suffered rapid loss of bilateral central vision with placoid lesions at the level of the retinal pigment epithelium and choriocapillaris scattered in the posterior pole of the fundus. In addition, acute vasculitis of the retinal veins was remarkable and widespread throughout the posterior pole and midperiphery. These inflammatory signs subsided in several weeks and were succeeded by recovery of the normal visual acuity with residual pigment derangements in the deep retina. Sixteen months after the onset of the disease choroidal neovascular membranes developed in the macular region of the left eye, followed by haemorrhagic macular detachment and marked visual loss. Significant increases in the serum cold agglutinin titre occurred as isolated laboratory findings concurrently with the acute stage of the disease and the late macular complication, though no clinical or other laboratory sign suggested viral infection.

Adult↗
PubMed1986

Haemorrhage in the lens: spontaneous occurrence in congenital cataract.

A 2-month-old female infant had bilateral congenital cataract. In the left eye a blood clot was situated on the subcapsular polar cataract. An uneventful lensectomy combined with anterior vitrectomy by the pars plicata approach revealed remnants of the posterior portion of hyaloid artery on the optic nerve head. It is likely that the spontaneous and long-lasting haemorrhage in the lens had been caused by rupture of the anterior end of the hyaloid artery attached to the posterior lens surface and had occurred in the late prenatal or early postnatal period.

Cataract↗
PubMed1986

Gyrate atrophy of the choroid and retina: 15 Japanese patients.

We examined 15 Japanese patients who had gyrate atrophy of the choroid and retina with hyperornithinaemia. Their visual acuities fell to 0.2 or worse in the second or third decade of life. Myopia developed late in the first decade, and the refractions decreased to -10 or -15 dioptres at age 20. Tunnel vision developed at approximately age 20. Our results suggested that the visual functions of Japanese patients were worse in the third decade or later than similarly affected Finnish patients.

Adolescent↗
PubMed1986

Purification of antibody against peanut agglutinin-receptors of bovine interphotoreceptor matrix.

From rabbit antiserum against peanut agglutinin (PNA)-receptors of the bovine interphotoreceptor matrix, an antibody was isolated by immunoaffinity chromatography on immobilized PNA-receptors. The antibody reacted with the bovine interphotoreceptor matrix at the molecular weight of 130,000 daltons. Immunohistochemical studies revealed that the antibody was bound not only to the surfaces of the cone photoreceptor cells but also to the surfaces of the rods, suggesting that the antibody purified here may have been formed by the major structure of glycoprotein that is common in the interphotoreceptor matrix around the cones and rods.

Animals↗