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Biomedical subjects

N Ohba

Publications and source records attributed to N Ohba.

At least 145 records · Page 8Linked to original sources
PubMed1985

Fundus flavimaculatus: polymorphic retinal change in siblings.

A 12-year-old boy and an 11-year-old girl, siblings of healthy, consanguineous parents, had a bilateral retinal dystrophy with a gradual loss of vision. The brother showed a bull's eye macular change with sparse fundus flavimaculatus type flecks. The sister had numerous fleck lesions of fundus flavimaculatus throughout the posterior fundus, but there was virtually no macular change. Thus the siblings presented instances of polymorphic expressivity of fundus flavimaculatus.

Child↗
PubMed1985

Effects of neuraminidase on lectin binding sites in photoreceptor cells of monkey retina.

Binding of sugar-specific lectins to the monkey retina was investigated with particular reference to the effects of pretreatment with neuraminidase on the photoreceptor cells. Neuraminidase-treated or untreated retinal sections were examined with a fluorescence microscope after incubation with the following fluorescein-labeled lectins: peanut agglutinin (PNA), wheat germ agglutinin (WGA), Ricinus communis agglutinin-1 (RCA-1) and Dolichos biflorus agglutinin (DBA). In the neuraminidase-untreated tissue, PNA, which is specific for D-galactose beta 1----3 N-acetyl-D-galactosamine (Gal beta 1----3GalNAc), was bound preferentially to the cones, and after treatment of sections with neuraminidase, PNA could bind to both cones and rods. WGA, which is specific for sialic acid and N-acetyl-D-glucosamine, was strongly bound to the rods but moderately to the cones without neuraminidase pretreatment, whereas neuraminidase-treated sections showed a weak binding. RCA-1, which is specific for D-galactose, showed patchy fluorescence on the basal and distal portions of the outer segments of the cones and rods, whereas neuraminidase-treated sections had uniform fluorescence throughout the tissues. DBA, which is specific for N-acetyl-D-galactosamine, did not bind to either cones or rods before and after neuraminidase treatment. These results suggest that there is a difference in the carbohydrate chains of glycoconjugates in the cones and rods: in the cones Gal beta 1----3GalNAc may be the terminal sugar as recognized by PNA, whereas in the rods this sugar is contained in the carbohydrate chain but masked by terminal sialyl residues so that those glycoconjugates are inaccessible to PNA without neuraminidase treatment.

Animals↗
PubMed1984

Corneal lesions induced by the systemic administration of capsaicin in neonatal mice and rats.

Following a single subcutaneous injection of capsaicin to neonatal mice, a high incidence of corneal lesions with opacity developed after a long latency. The intensity of the lesions progressed for about 1 month in animals which had received a high dose (50 or 100 mg/kg) of capsaicin. Although the intensity gradually decreased thereafter, 50% of animals still exhibited a visible opacity 6 months after treatment. Similar corneal lesions were also produced in neonatal rats which had been injected with capsaicin. It is suggested that the corneal lesions induced by capsaicin may be due to destruction of the trigeminal nerve.

Aging↗
PubMed1984

Capsaicin-induced neuroparalytic keratitis-like corneal changes in the mouse.

A single subcutaneous injection of 12.5-100 mg kg-1 capsaicin to newborn mice produced gross corneal changes. The changes were manifest about three weeks after capsaicin treatment and progressed dose-dependently from slight punctate vesiculations in the epithelium to diffuse edematous opacities and vascularizations in the stroma, followed by recovery in several weeks with or without residual scars. Control newborn mice with vehicle solution did not show any corneal abnormality. The most prominent histopathological feature of the affected corneas was a marked loss of nerve axons in the epithelium with associated disorganization of the epithelium. Similar corneal changes were observed with systemic capsaicin treatment to young or adult mice. The pathogenesis of the capsaicin-induced corneal changes was discussed with reference to the trophic action of the trigeminal nerve.

Animals↗
PubMed1984

Application of lectins for detection of goblet cell carbohydrates of the human conjunctiva.

Paraffin-embedded and frozen biopsies from the human conjunctival epithelium were examined by fluorescence microscopy after labeling with eight fluorescein-conjugated lectins: wheat germ agglutinin; soybean agglutinin; peanut agglutinin; Ricinus communis agglutinin-1; Limulus polyphemus agglutinin; Ulex europaeus agglutinin-1; Dolichos biflorus agglutinin; concanavalin A. The lectins were used as specific molecular probes to detect carbohydrate composition of glycoproteins secreted from the conjunctival goblet cells. The labeling pattern of goblet cells and conjunctival epithelial surfaces with various lectins suggested that N-acetyl-glucosamine, galactose, N-acetyl-galactosamine and sialic acid are contained in goblet cells and contribute to the formation of tear mucus glycoprotein. Fucose and mannose, which are present in the tear mucus, were not detectable in goblet cells.

Aged↗
PubMed1984

Binding sites of peanut agglutinin in mammalian retina.

Histochemical studies were carried out of the binding sites of a lectin, peanut agglutinin (PNA), in the mammalian retina, using lectin labeled with either fluorescein or horseradish peroxidase. In all mammalian species examined, monkey, pig, cat and rabbit, the cones were intensely labeled with the lectin but the rods were unlabeled. The cone synaptic pedicles, the inner synaptic layer, the internal limiting membrane and the retinal vessels were also labeled. It is suggested from the specificity of the PNA binding that galactosyl and/or galactosaminyl residues are present in the mammalian cones, but not in the rods.

Animals↗
PubMed1983

Phakic retinal detachment associated with atrophic hole of lattice degeneration of the retina.

Forty patients with phakic nontraumatic retinal detachment caused by atrophic retinal hole of lattice degeneration were reviewed. The condition was characterized by insidious, slowly developing shallow detachment, with frequent formation of demarcation lines. Often, the patients did not recognize their visual problems until the detachment had extended to the macular region. Young patients under 40 years of age were more common than older patients. Myopic refractive errors were frequently associated. The results of surgical repair were favorable. The risk of retinal detachment in lattice degeneration with atrophic holes was estimated to be about 1 in 90 patients, and prophylactic treatment for this common anomaly is not readily recommended.

Adolescent↗
PubMed1983

Localization of fluorescence-labeled lectin binding sites on photoreceptor cells of the monkey retina.

The binding of eight fluorescence-labeled lectins to the photoreceptors of the monkey retina was investigated using a post-embedding staining method. Concanavalin A (specific for mannosyl and glucosyl residues) bound to the outer and inner segments of both rods and cones, while the degree of staining was more intense in the rods. The rod outer segments showed patchy fluorescence and the proximal portions of the inner segments were diffusely stained. Wheat germ agglutinin (specific for sialyl and N-acetylglucosaminyl residues) bound preferentially to the surface of the outer and inner segments of both rods and cones. Ricinum communis agglutinin-1 (specific for galactosyl residues) stained the rod outer segments in patches, particularly strongly in the region dividing the outer and inner segments. The cones were also stained, although faintly, in the same pattern as the rods. The distal halves of the rods and cones showed diffuse weak staining and their proximal halves stained spotty. Peanut agglutinin (specific for Gal beta 1 leads to 3GalNAc sequence) bound preferentially to the cones and only scarcely to the rods. The external surface of both outer and inner segments of cones were uniformly stained; the interior of the cone outer segments was also stained, while the interior of the inner segments was not. Two lectins specific for fucosyl residues, namely, Ulexeuropaeus agglutinin-1 and Lotustetragonolobus agglutinin, bound diffusely to the distal halves of the inner segments of both rods and cones. Lectins reacting with N-acetyl-galactosamine residue, i.e. Dolichos biflorus agglutinin and soybean agglutinin, bound weakly to the distal portions of rods and cones.

Animals↗
PubMed1982

Phakic retinal detachment associated with cystic retinal tuft.

Of 200 consecutive cases with phakic nontraumatic rhegmatogenous retinal detachment, 15 cases (7.5%) were causally related to cystic retinal tuft. The cystic retinal tuft was characterized by a small, elevated and chalky-white lesion with cystic features and pigment proliferations. The lesions were present in the equatorial region of the retina, and two types of retinal breaks were found, i.e., horseshoe- or crescent-shaped flap tears and round opercular tears. Flap tears were found more frequently, which were located at the juxtabasal zone of the equator and induced acute, highly elevated detachments. Opercular tears were located at the extrabasal zone of the equator and caused relatively slowly developing, shallow detachments. It was concluded that the cystic retinal tuft is an important vitreoretinal abnormality predisposing to rhegmatogenous retinal detachment.

Adult↗
PubMed1982

Genetics of lattice degeneration of the retina.

First-degree relatives of proband patients with lattice degeneration of the retina revealed a significantly higher prevalence of the disease than the prevalence in the general population: the former had the disease about three times as frequently as the latter. The observed data were analyzed in terms of their accordance with recognized genetic models. The inheritance pattern did not fit well to a monogenic mode of inheritance, and it was hypothesized that a polygenic or multifactorial mode of inheritance is the most likely for lattice degeneration of the retina.

Adolescent↗