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Biomedical subjects

T Shiono

Publications and source records attributed to T Shiono.

At least 73 records · Page 4Linked to original sources
PubMed1990

Pattern dystrophy of the retinal pigment epithelium.

The authors describe a family in which one member had pattern dystrophy of the retinal pigment epithelium. The proband also had neovascular membranes which resulted in decreased visual acuity. Two other family members had abnormal electro-oculographic findings, but a clinical normal-appearing fundus that could represent an early stage of the disease. The incidence of this condition in this family indicates autosomal dominance as the inheritance pattern of this dystrophy.

Adult↗
PubMed1990

The effect of oral metyrapone on aqueous humor dynamics in normal human eyes.

We studied the possible influence of oral metyrapone tartrate (which inhibits the adrenal biosynthesis of cortisol) on the rate of aqueous humor flow in 9 eyes of 8 normal subjects by fluorophotometry. On the control day, the mean value of Ko was 1.04 +/- 0.32 min-1 x 10(-2), where Ko was the loss coefficient from the anterior chamber. On the metyrapone trial day, the mean value of Ko was 0.63 +/- 0.15 min-1 x 10(-2). The mean difference in Ko between the two periods was significant (P less than 0.005). These results indicated that systemic metyrapone administration decreases the rate of aqueous humor flow.

Administration, Oral↗
PubMed1990

A case of miliary tuberculosis with disseminated choroidal haemorrhages.

A 20-year-old Japanese man had generalised miliary tuberculosis. Although he had no ocular symptoms, choroidal miliary tuberculosis with pleomorphic findings, including disseminated choroidal haemorrhages, was noted in both fundi. The haemorrhages disappeared as the patient's condition improved on medical therapy. Disseminated choroidal haemorrhages should be looked for in patients with miliary tuberculosis.

Adult↗
PubMed1989

Point mutation affecting processing of the ornithine aminotransferase precursor protein in gyrate atrophy.

A generalized deficiency of the mitochondrial enzyme, ornithine aminotransferase (OAT) is the inborn error in gyrate atrophy, an autosomal recessive degenerative disease of the choroid and retina of the eye that leads to blindness. Southern analysis, using the OAT cDNA probe, of the OAT gene in a gyrate atrophy patient whose level of OAT protein is markedly decreased indicated the functional gene to be grossly intact. Northern analysis of his OAT mRNA demonstrated only half the normal level of OAT message, suggesting expression of only one of the two alleles of the OAT gene. A functional assay of the expressed OAT mRNA by in vitro translation and immunoprecipitation with anti-human OAT antibody indicated synthesis of an OAT protein from the message. The expressed message was cloned and sequenced and was shown to contain a single base change from C to T, resulting in an amino acid codon change from CAT (histidine) to TAT (tyrosine) at position 319 in the translated OAT protein. The mutant and normal OAT precursors were synthesized using transcriptional expression clones of OAT and in vitro translation of the expressed mRNA and tested in an in vitro mitochondrial transport/processing system. The results indicate that the mutant OAT precursor from the gyrate atrophy patient can be transported to the mitochondria but is minimally processed there, which would lead to degradation of the labile precursor and loss of OAT activity as phenotypically observed.

Adult↗
PubMed1989

Immunocytochemical localization of ornithine aminotransferase in human ocular tissues.

Gyrate atrophy of the choroid and retina is a rare inherited form chorioretinal degeneration caused by a deficiency of ornithine aminotransferase. We localized the enzyme in human ocular tissues using immunocytochemical procedures. Immunoreactivity was observed in the nonpigmented epithelium of the ciliary body and lens epithelium. In the retina, ganglion cells and some amacrine cells were immunoreactive. Pigmented granules made it difficult to identify immunoreactive products in the iris, pigmented epithelium of the ciliary body, choroid, and retinal pigment epithelium. Our findings suggested that ornithine aminotransferase plays an important role in ornithine metabolism in these oculartissues.

Eye↗
PubMed1989

Lysosomal enzyme activities in ocular tissues and adnexa of rabbits.

We examined biochemically the distribution of lysosomal enzyme activities in the ocular tissues and adnexa of albino rabbits using p-nitrophenyl derivatives. The pink and white lobes of Harderian gland disclosed the highest specific activities of acid phosphatase, N-acetyl-beta-D-glucosaminidase, and alpha-L-fucosidase. The lacrimal gland showed moderately high specific activities of acid phosphatase and N-acetyl-beta-D-glucosaminidase. The optic nerve, brain, ciliary body plus iris, and retina plus choroid exhibited nearly the same specific enzyme activities. The tear fluids showed higher lysosomal enzyme activities than did the serum. To our knowledge, this is the first reported measurement of lysosomal enzymes in Harderian gland, lacrimal gland, and optic nerve of the rabbit.

Animals↗
PubMed1989

[Application of NMR in the neurology--in its future].

The development of NMR technique is surprisingly progressive also at present. In this article, firstly we want to report our clinical experiments about mainly congenital and development anomalies, vascular disorders, dysmyelinating or demyelinating disorders, and neurodegenerative disorders. Secondly we report about the new techniques of MR imaging and MR spectroscopy those are applicable in clinical studies at present and in the near future. Fast scan imaging technique using gradient echo acquisition enables us to perform CSF cine-mode study, MR angiography, and three-dimensional imaging. Detectability of intracranial calcification is higher in the fast scan images than in the conventional spin-echo images. MR imaging and spectroscopy using other than proton are not performed screening at present. However, in vivo MR imaging of sodium, fluorine, and phosphorus can be used, and their clinical utilities are now evaluated. In vivo MR spectroscopy of proton is also used in some institutes. Its clinical utility is already reported and this application in clinical studies is strongly expected.

Adolescent↗
PubMed1989

[Role of MRI in the pediatric central nervous system disorders].

Recent rapid development of the MRI system has enabled us to diagnose precisely the disorders of the central nervous system (CNS) also in neonates and young children. Because of a long studying time, the use of oral chloral hydrate or other alternative drugs for sedation, such as secobarbital and meperidine, is necessary for young children under 6 years of age. The advantages of MRI are the optional plane imaging, a high contrast resolution, and the artifact-free imaging from the surrounding bones and air. MRI can detect myelination disorders and the lesions in the posterior fossa, the middle fossa, and the spinal canal. These abnormalities are difficult to depict with conventional X-ray CT scanning. MRI is useful also for the survey of various congenital anomalies of the brain and the spine. Furthermore, it is sensitive enough to detect the CNS blood flow and the cerebrospinal fluid (CSF) flow. Arteriovenous malformation, moyamoya disease, and sinus thrombosis are diagnosed by MRI without using contrast media, CSF flow void phenomena in the aqueduct and the Monro's foramina are indexes of the CSF pathway obstruction and of normal pressure hydrocephalus.

Adolescent↗
PubMed1989

Effect of topical anesthesia on secretion of lysozyme and lysosomal enzymes in human tears.

Unilateral topical anesthesia affected the secretion of human tear fluid and its concentrations of lysozyme and lysosomal enzymes. Results of a Schirmer's test with 0.4% oxybuprocaine showed that topical anesthesia reduced the mean test value by 47% and the secretion of protein, lysozyme, acid phosphatase, and N-acetyl-beta-D-glucosaminidase by 30%, 45%, 31%, and 33%, respectively. These results indicated that the paper strip induced reflex secretion from only the stimulated eye. The enzyme activity of lysozyme per fluid volume in tears from anesthetized eyes was as high as that from eyes without anesthesia, while acid phosphatase and N-acetyl-beta-D-glucosaminidase had higher activities. The amount of protein in the tear fluid was higher in anesthetized eyes than in unanesthetized eyes. Enzyme activity of lysozyme per protein of the tear fluid in the anesthetized eyes was lower than in the eyes without anesthesia, while acid phosphatase and N-acetyl-beta-D-glucosaminidase had higher activities per protein in the eyes with anesthesia. These findings disclosed that the concentrations of total protein, acid phosphatase, and N-acetyl-beta-D-glucosaminidase increased, while lysozyme value was constant when the tear secretion decreased.

Acetylglucosaminidase↗
PubMed1988

Acid hydrolases in the bovine lens epithelium.

Acid hydrolases (acid phophatase, N-acetyl-beta-D-glucosaminidase, alpha-D-mannosidase, alpha-L-fucosidase, and beta-D-glucuronidase) in the bovine lens epithelium were studied biochemically. p-Nitrophenyl derivatives were used as substrate. All enzymatic activity was found to be much higher in the epithelium than in the cortex and nucleus. The properties of acid phosphatase, N-acetyl-beta-D-glucosaminidase, and alpha-D-mannosidase were also studied, yielding Km values of 0.28, 0.95, and 0.53 mM, respectively. The optimal pH of these enzymes was acidic. Among the subcellular fractions, both acid phosphatase and N-acetyl-beta-D-glucosaminidase had the highest enzymatic activities in the 20,000 g precipitate fraction, while alpha-D-mannosidase showed no difference in activity among the subcellular fractions, suggesting that alpha-D-mannosidase in the bovine lens epithelium is nonlysosomal.

Animals↗
PubMed1988

Expression defect of ornithine aminotransferase gene in gyrate atrophy.

A generalized deficiency in the mitochondrial enzyme, ornithine aminotransferase (OAT: EC 2.6.1.13), is the hallmark of gyrate atrophy (GA), a hereditary degenerative disease of the choroid and retina of the eye that leads to blindness. A human OAT cDNA, previously constructed and characterized in our laboratory, and anti-human OAT antibody were used as probes to examine the OAT gene, mRNA and protein of GA patients. A blot analysis of the genomic DNAs, RNAs and proteins of 14 GA patients identified a case with a partial heterozygous deletion of the functional OAT gene located on chromosome 10, no detectable OAT mRNA, and a barely detectable level of OAT antibody-reactive protein. The rest of the cases showed grossly normal OAT gene, mRNA, and variably reduced levels of OAT protein. A restriction fragment length polymorphism (RFLP) was identified in the functional OAT gene sequence with EcoRI which may be useful for prenatal diagnosis of GA. RFLPs were also identified in the OAT-related gene sequences located on the X chromosome with Hind III and Pst I which may potentially show linkage to X-linked retinitis pigmentosa locus. The finding of an OAT gene, mRNA, and protein defect in a GA case constitutes the first real demonstration of the molecular genetic defect of OAT in GA.

Choroid↗
PubMed1987

Temporary corneal oedema after acute intake of alcohol.

A 65-year-old man had diffuse, bilateral corneal oedema after acute intake of alcohol. Three days later the total opacification began to clear from the peripheral area towards the centre of the cornea. One month later both corneas were completely clear, and visual acuity was 20/20 in both eyes. Specular microscopy showed in the right eye greatly enlarged endothelial cells, which subsequently shrank, and they showed some pleomorphism six months later. The pleomorphic endothelial cells in the left eye changed little with time. Our findings suggested that the corneal oedema in this patient resulted from temporary endothelial dysfunction with extensive cell loss.

Aged↗
PubMed1987

Pigment deposition in the anterior segment caused by melanocytoma of the optic disc.

A 34-year-old Japanese woman had a melanocytoma of the optic disc with scattered pigment particles in the vitreous in the left eye in 1970. Fifteen years later, we noticed pigment dispersion on the posterior lens surface, iris root, and trabecular meshwork, which resembled findings often caused by ocular malignant melanoma. Because the melanocytoma of the optic disc had decreased in size and the number of dispersed pigment particles in the vitreous cavity was reduced, it appeared that the pigmented particles produced by partial necrosis of the melanocytoma had resulted in the pigmentation of the anterior segment.

Adult↗
PubMed1987

Delta 1-pyrroline-5-carboxylate dehydrogenase in the bovine ciliary body and iris.

Delta 1-pyrroline-5-carboxylate dehydrogenase extracted from the combined ciliary body and iris of bovine eyes was studied biochemically. The enzyme was purified 120-fold. The partially purified enzyme had broad optimum at pH 8.0. Apparent Km values for DL-delta 1-pyrroline-5-carboxylate and NAD were 0.14 and 0.18 mM, respectively. The enzyme activity was strongly inhibited by GABA, proline, hydroxyproline, and glutamine.

1-Pyrroline-5-Carboxylate Dehydrogenase↗
PubMed1987

Immunocytochemical localization of ornithine aminotransferase in rat ocular tissues.

Gyrate atrophy of the choroid and retina is a rare inherited form of chorioretinal degeneration due to a deficiency of ornithine aminotransferase (OAT). We localized the enzyme in rat ocular tissues using immunocytochemical procedures. Immunoreactivity was observed in the epithelia of ciliary body, iris, and lens. Retinal pigment epithelium and Müller cells were immunoreactive in the retina. A little immunoreactive product was found in the choroid. Our findings suggested that OAT plays an important role in ornithine metabolism in these ocular tissues.

Animals↗