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Biomedical subjects

S Hayasaka

Publications and source records attributed to S Hayasaka.

At least 217 records · Page 12Linked to original sources
PubMed1987

Nystagmus and subnormal electroretinographic response in nonketotic hyperglycinemia.

We examined ophthalmologically two siblings with nonketotic hyperglycinemia who had negligible activities of glycine cleavage system in the liver. Both had jerky nystagmus. The elder brother had a normal electroretinographic response, while the younger brother's response was subnormal. There may be a close association of subnormal electroretinographic response and hyperglycinemia, because glycine can act as an inhibitory neurotransmitter in the retina.

Amino Acid Metabolism, Inborn Errors↗
PubMed1987

Lysosomal enzymes in tear fluids from patients with Terrien's marginal corneal degeneration.

We examined biochemically the lysosomal enzyme activities in tear fluids from patients with mild myopia, senile cataract, and Terrien's marginal corneal degeneration. Tear acid phosphatase activities in Terrien's degeneration were almost the same as those in mild myopia and senile cataract, while those of N-acetyl-beta-D-glucosaminidase in Terrien's degeneration were higher. The high activity of tear N-acetyl-beta-D-glucosaminidase may be derived from the lacrimal gland and infiltrate histiocytelike cells in Terrien's marginal corneal degeneration.

Acetylglucosaminidase↗
PubMed1987

Secondary localized amyloidosis of the cornea caused by trichiasis.

A 43-year-old woman complained of gradual visual impairment, foreign body sensation, and a white mass in the right eye. Trichiasis and corneal excrescence were observed. A systemic examination revealed no concurrent disease; the family history was noncontributory. A lamellar keratoplasty was performed. An amyloid deposit was found in the excised specimen histopathologically. Secondary localized amyloidosis of the cornea caused by trichiasis is a rare condition.

Adult↗
PubMed1987

Retinal microaneurysms in a patient with drug-induced aplastic anemia.

We examined ophthalmologically a patient with drug-induced aplastic anemia. The patient had good visual acuity and full visual fields, but small round hemorrhages and small red dots were seen ophthalmoscopically in both fundi. Fluorescein angiography revealed punctate hyperfluorescence from the early to late phases, indicating microaneurysms. We believe that retinal microaneurysms are not rare in association with anemia.

Anemia, Aplastic↗
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

Affinity of ocular acid-insoluble melanin for drugs in vitro.

The authors examined spectrophotometrically the ability of drugs to bind with ocular acid-insoluble melanin. Each drug, at 5 X 10(-5) M, was incubated at 37 degrees C for 8 hr with 4 mg of melanin in 20 mM potassium phosphate buffer (pH 7.4 and 8.0) or in 20 mM acetate buffer (pH 4.8). The authors findings showed that chloroquine, thioridazine, befunolol, pindolol, daunomycin, and 5-fluorouracil bound to melanin (pH 4.8, 7.4, and 8.0). Methotrexate bound to melanin (pH 4.8 but not at 7.4 and 8.0). Pilocarpine, epinephrine, acyclovir, vincristine, and colchicine did not bind to ocular acid-insoluble melanin.

Animals↗
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↗
PubMed1986

Leber's congenital amaurosis associated with hyperthreoninemia.

Two siblings had Leber's congenital amaurosis. The girl (Patient 1) showed blindness shortly after birth, absent pupillary light reflex, and multiple round, white spots in both fundi. Her serum threonine level was increased (2.0 to 5.3 mg/dl; normal, 0.78 to 1.82 mg/dl). She died of massive pericardial effusion four months after birth. Her brother (Patient 2) was nearly blind shortly after birth. He had a poor pupillary light reflex and a nearly extinguished electroretinographic response. He also had hyperthreoninemia, hyperthreoninuria, hepatomegaly, and mental and physical retardation. We suspect a close relationship between hyperthreoninemia and Leber's congenital amaurosis in these siblings.

Amino Acids↗
PubMed1986

Ocular findings in childhood lactic acidosis.

We examined ophthalmologically nine children with lactic acidosis. All showed abnormal ocular findings. Optic atrophy was present in six patients, nystagmus in three, blepharoptosis in one, cataract in one, and limitation on abduction in one. We believe that optic atrophy is the most frequent ocular finding and that nystagmus and ophthalmoplegia are common associations in patients with childhood lactic acidosis.

Acidosis, Lactic↗
PubMed1986

Tyrosinase activity in human ocular malignant melanoma.

We examined tyrosinase activity in pigmented specimens from three cases of ocular malignant melanoma. Tissue (cholate-trypsin-treated) extract was prepared in cholate-phosphate buffer by homogenization, centrifugation, trypsin digestion, and hydroxylapatite column chromatography. Tyrosinase activity was spectrophotometrically assayed as dopa (L-3,4-dihydroxylphenylalanine) oxidase activity. Tyrosinase activity was detected in the cholate-trypsin-treated extracts. Enzyme activity was inhibited by phenylthiourea but not by 3-iodo-tyrosine. The enzyme was inactivated when extract was preheated or digested with pronase. We believe that our findings confirm the presence of tyrosinase activity in ocular malignant melanoma.

Aged↗
PubMed1986

Lysosomal enzyme activities of the bovine corneal endothelium.

A quantitative study was carried out on the lysosomal enzyme activities of the bovine corneal endothelium-Descemet's membrane preparation. The corneal endothelium and Descemet's membrane were peeled off together. Cathepsin D was assayed using hemoglobin as substrate; N-acetyl-beta-D-glucosaminidase, beta-glucuronidase, acid phosphatase, and alpha-mannosidase were also examined using p-nitrophenyl derivatives as substrate. The proportions of N-acetyl-beta-D-glucosaminidase, cathepsin D, and beta-glucuronidase of the Descemet's membrane-endothelium complex were particularly high: 11.5%, 12.6%, and 12.5% of the whole cornea, respectively. Corneal endothelial cells also showed high activities of acid phosphatase and alpha-mannosidase (3.8%, and 5.0% of the whole cornea, respectively), while the protein and DNA contents were 0.5% and 0.5% in the complex. Lysosomal enzyme activities in the complex were also compared with those in other ocular tissues and were determined by the same methods at the same time.

Animals↗
PubMed1986

Acid hydrolases in the bovine corneal epithelium.

The activities of acid phosphatase, N-acetyl-beta-D-glucosaminidase, alpha-mannosidase, alpha-fucosidase, beta-glucuronidase, arylsulfatase, and cathepsin D were biochemically investigated in the bovine cornea by separating the tissue into two layers, epithelium and stroma-endothelium. Acid phosphatase, alpha-mannosidase, alpha-fucosidase, and arylsulfatase disclosed much higher activities in the epithelial layer than in the stroma-endothelial layer. The other enzymes showed little difference in enzyme activity between the two layers.

Animals↗
PubMed1986

Acidic lens-protein-degrading activity in aqueous humour.

Lens-protein-degrading activity in human aqueous humor was determined biochemically. Proteolytic activity was found in the pellet of aqueous humor from patients with Morgagnian cataract, traumatic cataract, after cataract, traumatic lens luxation, and phacolytic glaucoma. The activity was found at pH 3.8 and it was inhibited partly by pepstatin or leupeptin. Possibly, cathepsin D and lysosomal thiol proteinases in the macrophages play a major role in the degradation of escaping lens protein under pathologic conditions.

Animals↗
PubMed1986

Malignant melanoma of the choroid in a mother and retinoblastoma in her son.

A 31-year-old woman was diagnosed as having a malignant melanoma of the choroid in the right eye. Twenty months later her 7-year-old son was diagnosed as having retinoblastoma in the right eye. Both diagnoses were confirmed histopathologically after enucleation. A chromosomal study revealed normal karyotypes in the son. The family history was positive for cancer of the stomach. The implications of this rare association are discussed.

Adult↗
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

Two Japanese cases of battered child syndrome with retinal hemorrhage.

We present 2 cases of battered child syndrome with retinal hemorrhage. Case 1 is a 6-year-old boy who was blinded in both eyes following abuse by his mother's common-law husband. Retinal hemorrhages and optic atrophy were found in both eyes. Case 2 is a 6-month-old boy who developed dyspnea following episodes of abuse by his mother's common-law husband. Retinal hemorrhages were visible in both fundi. We believe that retinal hemorrhage is the most frequent clinical finding in abused children and its presence should alert the ophthalmologist to suspect battered child syndrome.

Battered Child Syndrome↗