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S Hayasaka

Publications and source records attributed to S Hayasaka.

At least 19 recordsLinked to original sources
PubMed1996

The dilute-lethal (dl) gene attacks a Ca2+ store in the dendritic spine of Purkinje cells in mice.

The absence of smooth endoplasmic reticulum (SER) in the dendritic spine of Purkinje cells was found in dilute-lethal (dl) mouse cerebella as detected by immunohistochemistry using anti-inositol 1,4,5-triphosphate receptor antibody and electron microscopy. Since SER in the spine has been suggested to play a crucial role for synaptic regulation as an intracellular Ca2+ store (for reviews, see [Miller, R.J., Prog. Neurobiol., 37 (1991) 255-285: Simpson, P.B., Challiss, R.A.J. and Nahorski, S.R., Trends Neurosci., 18 (1995) 299-306]), a neurological defect, characterized by clonic convulsions with opisthotonus and ataxia, in the dilute-lethal mouse with homozygous trait may be attributable to the absence of SER in the dendritic spine of Purkinje cells.

Animals↗
PubMed1996

Endoplasmic reticulum is missing in dendritic spines of Purkinje cells of the ataxic mutant rat.

Dilute-opisthotonus (dop) is a spontaneous ataxic mutation in the rat, regulated by an autosomal recessive gene. Immunohistochemical staining with anti-inositol 1,4,5-trisphosphate receptor antibody and electron microscopic examinations revealed that the endoplasmic reticulum in dendritic spines of Purkinje cell was missing in the ataxic rat. This could impair the intracellular signal transduction in the parallel fiber-Purkinje cell synapse, and be a cause of the severe ataxic movement.

Animals↗
PubMed1996

Follow-up study on histogenesis of microcephaly associated with ectopic gray matter induced by prenatal gamma-irradiation in the mouse.

Brain malformation with ectopic gray matter was visualized with magnetic resonance imaging in small-sized heads of prenatally exposed atomic bomb survivors. The identical brain malformation was reproduced in mice and its histogenesis was studied in the present experiment. Pregnant mice were exposed to 60Co gamma-irradiation at a single dose of 1.5 Gy on embryonic day 13 (E13), and then injected intraperitoneally with 30 mg/kg BrdU on E15. The extensive dead cells appeared throughout the brain mantle at 6 hours (h) after exposure. On E16 cell aggregations formed rosettes. On E18 a high proportion of BrdU-labeled cells reached the superficial layers of the cortical plate with the remaining cells located in the ectopic neuronal masses. The quantitative study showed that labeled cells in layers II to III were fewer and those in layers IV to VI more numerous in the prenatally irradiated adult mice than in controls. The anti-GFAP immunostaining revealed that the glial fibers in the irradiated mice were preserved, but disorganized. These findings suggested that the majority of migrating neurons were able to arrive at their normal layers, but some neurons remained due to the interrupted migratory pathway and eventually formed ectopic neuronal masses beneath the subcortical white matter.

Age Factors↗
PubMed1996

Selective reduction of the S cone electroretinogram in diabetes.

AIMS: To determine whether the short wavelength sensitive (S) cone electroretinogram (ERG) is selectively altered in diabetic patients with and without retinopathy. METHODS: Ganzfeld spectral flashes in the presence of bright white background illumination were used to elicit S cone ERGs is 15 non-retinopathic diabetics, 16 background retinopathic diabetics, and 16 age matched normal controls. RESULTS: The amplitude of the S cone ERG b-wave was significantly reduced in both non-retinopathic and retinopathic diabetics. An action spectrum based on equal response criteria revealed a selective loss of S cone sensitivity in diabetics. However, no significant difference was observed in the long and middle wavelength sensitive cone ERG. CONCLUSIONS: Diabetic patients showed selective reduction of the S cone ERG, which is thought to reflect changes in the outer retina.

Adult↗
PubMed1996

Undetectable S cone electroretinogram b-wave in complete congenital stationary night blindness.

AIMS: The short wavelength sensitive (S) cone electroretinograms (ERGs) were examined in two patients with the complete type of congenital stationary night blindness (CSNB). METHODS: Ganzfeld spectral flashes in the presence of strong white adapting fields were used to elicit the S cone ERGs. RESULTS: The S cone ERG b-wave was not detectable to short wavelength stimuli, while the mixed long (L) and middle (M) wavelength sensitive cone responses appeared normal in waveforms with normal amplitude in both patients. Both patients had normal colour vision on the Farnsworth Panel D-15. CONCLUSIONS: These ERG results indicated that the S cone system as well as rod system is more impaired in complete CSNB than the L and M cone system and that normal colour vision may not depend on a normal S cone ERG to full field stimuli.

Child↗
PubMed1996

Decreased aqueous-flare reaction to repeated applications of prostaglandin E2 to the cornea in pigmented rabbits.

To evaluate the effect of single or repeated topical applications of prostaglandin E2 (PGE2) to the cornea on the blood-aqueous barrier, we have measured the extent of flare in the anterior chamber of rabbit eyes at various time intervals. PGE2 was applied to the cornea for 4 min with the use of a glass cylinder in pigmented rabbits. Aqueous flare was measured by a laser flare cell meter. The flare intensity following the second application of 25 or 50 micrograms/ml of PGE2 was smaller than that following the first application. When 50 micrograms/ml of PGE2 was applied every day for 6 days, the flare intensity decreased significantly day by day. After consecutive applications of 10 micrograms/ml of PGE2 at hourly intervals, flare intensity increased up to 3 h, remained elevated from 3 to 5 h, and decreased thereafter. Repeated applications of 10 micrograms/ml of PGE2, every hour for 14 h every Monday, significantly decreased flare intensity week by week. Weekly applications of 50 micrograms/ml of PGE2 did not change flare intensity. This study indicates that the extent of the breakdown of the blood-aqueous barrier in the rabbit eye, as measured by the development of flare in the anterior chamber, is reduced with repeated PGE2 application.

Administration, Topical↗
PubMed1996

Effects of a nitric oxide synthase inhibitor on prostaglandin-induced aqueous flare elevation in pigmented rabbits.

To evaluate the possible role of nitric oxide in the pathogenesis of exogenous prostaglandin (PG) induced aqueous flare elevation, we examined the effect of NG-nitro-L-arginine methyl ester (L-NAME), an L-arginine analogue acting as a specific inhibitor of nitric oxide synthase, on the elevation of aqueous flare in pigmented rabbits. L-NAME was injected into the ear vein of the animals. PGE1, PGE2, and PGF2 alpha were administered topically to the cornea using a glass cylinder. Aqueous flare was measured using a laser flare cell meter. PGE1, PGE2, and PGF2 alpha increased the aqueous flare dose dependently (5-100 micrograms/ml). L-NAME inhibited PGE1-, PGE2-, or PGF2 alpha-induced aqueous flare elevation. L-NAME, injected 30-90 min before PG application, inhibited the aqueous flare elevation maximally. We believe that nitric oxide may be involved in the pathogenesis of PG-induced aqueous flare elevation in rabbits.

Animals↗
PubMed1996

Unilateral acute posterior multifocal placoid pigment epitheliopathy.

A 24-year-old woman complained of paracentral scotomas in her left eye. Her visual acuity was good bilaterally. Multifocal, creamy, yellow-white lesions were seen at the level of the pigment epithelium and choroid in the left fundus. Fluorescein angiography showed blockage at the early phase and hyperfluorescence at the late phase in the left eye. The right fundus remained normal during the follow-up period of 1 year. We believe that unilateral acute posterior multifocal placoid pigment epitheliopathy, as found in our patient, may be uncommon.

Acute Disease↗
PubMed1996

Branch retinal vein occlusion in a patient with Waardenburg syndrome.

A 43-year-old woman (case II-2) with dystopia canthorum, white forelock, blue iris in the left eye, hypopigmented fundi, and systemic hypertension complained of visible floaters in the left eye. Whitish branch retinal vein, preretinal hemorrhages and neovascularization were found in the left fundus. Her intraocular pressure in the left eye was sometimes elevated to 22 mm Hg. The patient's brother (case II-3) was reported to have blue irises in both eyes. We believe that these patients have Waardenburg syndrome, that branch retinal vein occlusion in case II-2 may be caused chiefly by systemic hypertension, and that elevated intraocular pressure associated with the blue iris may be partly involved in the pathogenesis of vein occlusion in the left eye.

Adult↗
PubMed1996

Incomplete occlusion of central retinal artery in a girl with iron deficiency anemia.

We examined a 13-year-old girl who complained of sudden loss of vision in her left eye. Ophthalmoscopic and fluorescein angiographic examinations revealed a clinical picture of incomplete occlusion of the central retinal artery. Laboratory test results showed iron deficiency anemia. The patient was treated with urokinase and ferrous sulfate. The patient's left visual acuity recovered from hand motion to 0.8.

Administration, Oral↗
PubMed1995

Ocular findings in Japanese women with nevus of Ota.

BACKGROUND: Nevus of Ota is common in Japanese women, but most patients are not examined ophthalmologically. METHODS: We performed ophthalmologic examinations on 16 Japanese women who had had bluish pigmentation in the periorbital region, sclera, and conjunctiva since birth. RESULTS: Fifteen patients had unilateral involvement, and one had bilateral lesions. The visual acuities were good, and the intraocular pressures were within normal range. All patients had a negative family history. Three patients had light pigmentation in the optic disc in the affected eye. CONCLUSION: We believe that optic disc pigmentation associated with nevus of Ota, as found in these three patients, may be common but have been rarely described.

Adolescent↗
PubMed1995

Immunohistochemical localization of epidermal growth factor receptor and epithelial antigen in tumors of the human conjunctiva, eyelid, lacrimal gland, and orbit.

BACKGROUND: Increased numbers of epidermal growth factor (EGF) receptors are observed in squamous cell carcinomas of human lung, head, neck, and cervix. We studied the presence of EGF receptors and epithelial antigen in some ophthalmic lesions. METHODS: Immunohistochemical staining for EGF receptors was assessed in tumors of human conjunctiva, eyelid, lacrimal glands, and orbit with monoclonal antibodies (EGF-R1 and clone 29.1). Reactivity of Ber-EP4, which recognizes epithelial antigen, was also examined. RESULTS: Strong staining of EGF-R1 and clone 29.1 and weak to moderate staining of Ber-EP4 were demonstrated in conjunctival squamous cell carcinomas. Cell membranes of conjunctival papilloma were moderately or strongly stained with these antibodies. Ductal components in sebaceous gland adenoma of the eyelid and pleomorphic adenoma of the lacrimal gland were positively stained. The antibodies did not bind to reactive lymphoid hyperplasia of the orbit and Wegener's granulomatosis. Relatively good correlation for immunostaining reaction was observed among EGF-R1, clone 29.1, and Ber-EP4 in each tumor. CONCLUSION: Immunostaining using EGF-R1, clone 29.1, and Ber-EP4 may be useful in differentiating epithelial tumors from non-epithelial lesions. Strong immunostaining for EGF receptor may be the hallmark of epidermoid malignancy.

Adenoma↗
PubMed1995

Nondetectable S-cone electroretinogram in a patient with crystalline retinopathy.

We examined cone and rod electroretinograms to ganzfeld stimuli in a patient with crystalline retinopathy. The 54-year-old man complained of night blindness, blurred vision, and metamorphopsia in both eyes. His visual acuity was 10/200 in the right eye and 10/20 in the left eye; his subjective dark-adaptation threshold was elevated 1 log unit, and he made one tritan error on the Farnsworth Panel D-15. Specular microscopic examinations revealed tiny crystalline deposits in the limbal cornea bilaterally. Ophthalmoscopically, crystalline deposits were found in the posterior fundi. His light-adapted cone electroretinograms to white stimuli were diminished (about 30% of those of normal controls), with normal implicit times. His dark-adapted rod electroretinogram amplitudes were 10% of those of normal controls. The S-cone electroretinogram was not detectable to different spectral stimuli with strong white background, while the L-M-cone responses appeared normal in waveforms with reduced amplitude. These ERG results indicated that the patient's S-cone system is more highly impaired than the L-M-cone system, supporting the psychophysical evidence that the S-cone system is more vulnerable than other cone systems in retinal diseases.

Dark Adaptation↗
PubMed1995

Central retinal vein occlusion in a patient with anorexia nervosa.

PURPOSE/METHODS: We evaluated a unilateral retinal vascular abnormality in a 21-year-old woman with anorexia nervosa. RESULTS/CONCLUSION: The patient had weight loss, amenorrhea, and anemia. The left eye had a nonischemic central retinal vein occlusion and a visual acuity of 20/200. With treatment, the retinal hemorrhages disappeared and visual acuity in the left eye improved to 20/20. Central retinal vein occlusion may be a rare complication of anorexia nervosa.

Adult↗
PubMed1995

Retinopathy and subconjunctival haemorrhage in patients with chronic viral hepatitis receiving interferon alfa.

A total of 43 patients (86 eyes) with chronic viral hepatitis were examined prospectively before and after the start of interferon therapy. Of 37 non-diabetic patients, 23 (group A1) did not have retinopathy or subconjunctival haemorrhage, 11 (group A2) developed retinopathy, and three (group A3) exhibited subconjunctival haemorrhage during the treatment. In most eyes, the retinopathy disappeared after therapy was stopped. Of six diabetic patients, three (group B1) developed retinopathy and three (group B2) showed progression of existing retinopathy. Thrombocytopenia was not associated with the retinopathy in any patient. The patients' good visual acuity remained unchanged, even after retinal changes appeared. Ophthalmologists should be aware that retinopathy and subconjunctival haemorrhage may develop in patients with chronic viral hepatitis receiving interferon therapy.

Adult↗
PubMed1995

Intracameral ascorbic acid, glutathione and protein levels in albino and pigmented rabbits.

We performed a comparative investigation into differences between albino and pigmented rabbits in respect of intracameral concentrations of ascorbic acid, glutathione and total protein with high-performance liquid chromatography. The intracameral concentrations of reduced ascorbic acid, total ascorbic acid, reduced glutathione, total glutathione and protein in albino rabbits were similar (p > 0.05) to those in pigmented rabbits.

Animals↗
PubMed1995

Elevated anti-neutrophil cytoplasmic antibody titer in a patient with atypical orbital pseudotumor.

We recently examined a patient with ophthalmic manifestations of Wegener's granulomatosis in whom antineutrophil cytoplasmic antibody (cANCA) titers provided helpful diagnostic information. A 40-year-old man who had suffered from bilateral exophthalmos for 9 months was diagnosed initially as having idiopathic inflammatory pseudotumor. The patient exhibited purulent nasal discharge and microhematuria. A histopathologic study revealed vasculitis. His ANCA titer for cANCA was found to be evaluated, and our patient was subsequently diagnosed as having Wegener's granulomatosis. His ocular symptoms resolved and did not recur after treatment with corticosteroid in combination with cyclophosphamide. We believe that cANCA levels should be investigated in patients with orbital pseudotumor as a possible sign of Wegener's granulomatosis.

Adult↗