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Biomedical subjects

N Ohba

Publications and source records attributed to N Ohba.

At least 109 records · Page 6Linked to original sources
PubMed1991

[Classification of light-evoked distribution of interphotoreceptor matrix].

Distributional patterns of the interphotoreceptor matrix (IPM) under several different light conditions were examined in adult rats using colloidal iron staining. In the dark, the IPM distributed uniformly throughout photoreceptor outer segments including apical halves of inner segments. After exposure to light for 1 min, the colloidal iron-bound IPM concentrated in bands at apical and basal regions of outer segments and at apical inner segments. After exposure to light for 5-30 min, the IPM distributed throughout inner segments, in addition to the distribution at apical and basal outer segments. In excessive light, diffuse IPM staining was observed throughout the photoreceptor layer. These findings suggest that the light response of the IPM around outer segments precedes that around basal inner segments. It is also remarkable that the excessive light-induced distributional pattern of the IPM is similar to patterns in inherited retinal dystrophy and light-induced retinal degenerations.

Animals↗
PubMed1991

[Lectin binding in the interphotoreceptor matrix in neuraminidase-induced retinal detachment].

Binding sites of fluorescence isocyanate-labeled lectins, peanut agglutinin (PNA) and Ricinus communis agglutinin-1 (RCA-1), were studied in the interphotoreceptor matrix (IPM) of adult rat retinas that were pretreated with an intravitreous injection of neuroaminidase. The localization of binding sites to the subretinal IPM differed significantly between the two lectins. PNA bound to the subretinal IPM components in a cord-like fashion that formed a bridge between the apical photoreceptor outer segments and the surface of the RPE. On the other hand, RCA-1 showed homogeneously prominent binding to the subretinal space IPM, the intensity of which appeared to inversely correlate with the extent of neuraminidase-induced retinal separation. The results suggest that the IPM may consist of mucin-type glycoconjugates as recognized by PNA and serum-type ones as bound by RCA-1, and that these IPM components may play different roles in the maintenance and organization of photoreceptor-RPE complex, e.g. the mucin-type for the retinal adhesion and the serum-type for the transport of metabolites.

Animals↗
PubMed1990

The effects of pyrimidine and purine nucleotides on sialyltransferase activity in bovine neurosensory retina.

Effects of nucleotide phosphates on the sialyltransferase activity in the neurosensory retina of the bovine eye were studied. Enzyme activity was assayed using cytidine monophosphate-[14C]-N acetylneuraminic acid as a substrate and desialylated fetuin as an exogenous acceptor. Cytidine-5'-diphosphate and adenosine triphosphate inhibited the enzyme activity. Uridine diphosphate and guanosine diphosphate increased the enzyme activity at low concentrations and decreased the activity at high concentrations. Cyclic adenosine monophosphate and cyclic guanosine monophosphate increased the enzyme activity at concentrations up to 8 mM. It is thus concluded that sialyltransferase activity of the neural retina may be affected by various nucleotides, its alteration depending on either the type of nucleotides or their concentration.

Animals↗
PubMed1989

Noninfectious anterior uveitis in patients infected with human T-lymphotropic virus type I.

A consecutive series of 34 patients with HTLV-I-associated myelopathy (HAM), a neurological disease associated with human T-lymphotropic virus type I (HTLV-I), were studied with reference to endogenous ocular disorders. These patients were examined at the Kagoshima University Hospital between 1986 and 1988. Five of the 34 HAM patients showed noninfectious, granulomatous anterior uveitis responding to corticosteroid therapy and/or retinal microvascular changes such as isolated cotton-wool spots; one of the patients had recurrent uveitis. Additionally, twelve of 30 patients who had been infected with HTLV-I but remained healthy systemically had ocular manifestations similar to those in HAM patients were included in this study. The ocular lesions in these patients were not explained by any established disorders that manifest uveitis or retinal microangiopathy. Some of the HTLV-I-seropositive patients with ocular disorders showed antibodies against HTLV-I in the aqueous humor. This might have resulted from diffusion of serum antibodies through a damaged blood-aqueous barrier or local synthesis of antibodies. The HTLV-I infection might be primarily responsible for a certain form of endogenous anterior uveitis that has remained hitherto etiologically undefined.

Adult↗
PubMed1989

Pigmentary retinal degeneration in patients with HTLV-I-associated myelopathy.

Ophthalmological evaluations were made of the records of a series of 38 patients with HTLV-I-associated myelopathy, a chronic progressive myelopathy caused by human T-lymphotropic virus type I (HTLV-I). Four patients with no contributory family history showed pigmentary degenerative changes of the retina and choroid. Two of the patients (73-year-old woman, 68-year-old woman) had a progressive visual loss and night blindness with morphologic and functional features of diffuse pigmentary retinal degeneration. The other two patients (59-year-old man, 72-year-old man) complained of recently developed visual loss with sectorial or regional retinochoroidal atrophy. These elderly patients claimed that they had been healthy until a few years before presentation, not only visually but also neurologically. It was concluded, together with an epidemiologic consideration, that the coexistence of pigmentary retinal degeneration and HTLV-I-associated myelopathy is not simply chance but indicates a close association between the two conditions. It is proposed that HTLV-I infection might be a primary causative factor of degenerative changes of the retina and choroid, although the pathogenesis remains to be defined.

Aged↗
PubMed1989

Ocular manifestations in patients infected with human T-lymphotropic virus type I.

Ocular manifestations in patients infected with human T-lymphotropic retrovirus type I (HTLV-I) consisted of a wide range of neoplastic, infectious and noninfectious vascular or inflammatory lesions. These disorders were associated with two distinct HTLV-I-induced systemic diseases, ie, adult T-cell leukemia/lymphoma and HTLV-I-associated myelopathy. Five of the 10 cases of adult T-cell leukemia/lymphoma had inflammatory or opportunistic infectious ocular lesions, including cytomegalovirus retinitis or eyelid tumor as part of generalized lymphomas. Four of the 17 cases of HTLV-I-associated myelopathy showed noninfectious lesions such as isolated, transient cotton-wool spots and granulomatous iridocylitis. Twenty-four (26.9%) of 89 cases with various ocular diseases but no HTLV-I-induced systemic disease had antibodies to HTLV-I in the serum. The aqueous humor antibodies to HTLV-I in the seropositive carriers were negative, except one carrier case who showed isolated cotton-wool spots in one eye and massive vitreous opacities in the other eye.

Adult↗
PubMed1988

Lectin-cytochemical study on epithelial mucus glycoprotein of conjunctiva and pterygium.

The epithelium of pterygium and conjunctiva was studied with reference to cytochemical reactivity to six fluorescein-labeled lectins that recognize a certain carbohydrate residue(s) of cellular membrane-bound or secretory glycoprotein: Ulex europaeus agglutinin-1 (UEA-1, specific for fucose); Dolichos biflorus agglutinin (DBA, specific for N-acetylgalactosamine); peanut agglutinin (PNA, specific for galactose-beta 1-3N-acetylgalactosamine): wheat germ agglutinin (WGA, specific for N-acetylglucosamine and N-acetylneuraminic acid); Concanavalia ensiformis (Con A, specific for mannose); Ricinus communis agglutinin-1 (RCA-1, specific for galactose). Non-goblet epithelial cells of pterygium were labeled with UEA-1, DBA and PNA, while those of conjunctiva were not. Distribution density of goblet cells was larger in pterygium than in conjunctiva, but there was no distinct difference in lectin reactivity between the two tissues, with marked label with WGA, PNA and RCA-1. Con A did not bind to either pterygium or conjunctiva. The observations suggest the presence of anomalous mucus glycoproteins secreted from pterygium.

Aged↗
PubMed1988

Autosomal dominantly inherited optic nerve coloboma.

Four members of three consecutive generations of a family had congenital anomalies of the optic disk: deep excavation of the optic disk containing a mass of white glial tissue at its center, anomalous retinal vessels emerging from the peripheral aspect of the disk, and elevated annulus of peripapillary pigmentary disturbance. These optic disk anomalies occurred bilaterally with some inter- and intra-individual variable expressivity. Five of the eight affected eyes had profound visual loss, but three eyes showed normal vision. Two cases developed unilateral nonrhegmatogenous retinal detachment. There were no other ocular or systemic malformations. This family illustrates an instance of autosomal dominantly inherited optic nerve coloboma.

Adult↗
PubMed1988

A pedigree of Leber's congenital amaurosis.

A pedigree of Leber's congenital amaurosis compatible with autosomal recessive trait is reported. Two male infants from consanguineous parents had remarkable visual loss within the first year of life, with sluggish pupillary responses, poor fixations, minimal eyeground changes and absent electroretinograms on presentations at the ages of four or 14 months. Follow-up studies revealed definite progressions of eyeground abnormalities consisting of attenuated retinal arterioles, pepper- and salt-like appearance with numerous yellowish-white punctate lesions in the midperiphery, and pale optic nerves. Fluorescein angiographic study performed on one case showed multiple hyperfluorescent spots over the posterior and midperipheral eyegrounds suggesting alterations of the retinal pigment epithelium. These functional and morphological abnormalities of the retina were similar in the two siblings. Cycloplegic refractions revealed slight myopic or mixed astigmatism, but no marked hyperopia. The patients had normal physical and mental developments with no obvious systemic complications.

Blindness↗
PubMed1988

[Nonpenetrating brachiocephalic arterial injury].

The injury of brachiocephalic artery is uncommon in the blunt trauma and sometimes it was accompanied by other organ damages. We reported a case and reviewed 47 cases in literature. A 28-year-old woman was transferred to our hospital with the blunt chest trauma and the cerebral infarction due to the traffic accident. The cineangiogram showed complete obstruction at the middle portion of brachiocephalic artery and the subclavian steal-carotid recovery phenomenon. Thirty days after trauma, the operation was performed under the monitoring of right superficial temporal arterial pressure. The vessel with intimal defect was plugged by a clot and it was replaced with a Gore-Tex graft during simple occlusion of the right carotid, subclavian and brachiocephalic arteries without any monitoring pressure change. The postoperative course was uneventful and the symptom improved. The review decided that the main cause of the injury is traffic accidents and the cineangiogram is important to find the arterial damage and the monitoring of superficial temporal arterial pressure is helpful to avoid the brain ischemia during operation.

Accidents, Traffic↗