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Biomedical subjects

S Hayasaka

Publications and source records attributed to S Hayasaka.

At least 37 records · Page 2Linked to original sources
PubMed2000

Local calcium release in dendritic spines required for long-term synaptic depression.

We have used rats and mice with mutations in myosin-Va to evaluate the range and function of IP3-mediated Ca2+ signaling in dendritic spines. In these mutants, the endoplasmic reticulum and its attendant IP3 receptors do not enter the postsynaptic spines of parallel fiber synapses on cerebellar Purkinje cells. Long-term synaptic depression (LTD) is absent at the parallel fiber synapses of the mutants, even though the structure and function of these synapses otherwise appear normal. This loss of LTD is associated with selective changes in IP3-mediated Ca2+ signaling in spines and can be rescued by photolysis of a caged Ca2+ compound. Our results reveal that IP3 must release Ca2+ locally in the dendritic spines to produce LTD and indicate that one function of dendritic spines is to target IP3-mediated Ca2+ release to the proper subcellular domain.

2-Amino-5-phosphonovalerate↗
PubMed2000

The cutler-beard bridge flap technique with use of donor sclera for upper eyelid reconstruction.

We evaluated the Cutler-Beard bridge flap technique with the use of donor sclera for upper eyelid reconstruction. The right upper eyelid of a 22-year-old man (case 1) was bitten by a dog. A mass in the left upper eyelid of an 85-year-old man (case 2) was excised. Major full-thickness defects of the eyelid with small loss of tarsus were reconstructed with the use of donor sclera. Good cosmetic results were obtained. Major full-thickness defects of the upper eyelid with small loss of tarsus may be effectively reconstructed by the Cutler-Beard technique with use of donor sclera.

Adult↗
PubMed2000

Retrobulbar optic neuritis and rhegmatogenous retinal detachment in a fourteen-year-old girl with retinitis pigmentosa sine pigmento.

A 14-year-old girl complained of a sudden decrease in right visual acuity. The patient had night blindness, a mottled retina but no pigments, extinguished scotopic electroretinographic response, central scotoma in the right eye and rhegmatogenous retinal detachment. She had initially received laser photocoagulation around the retinal tear and then corticosteroid therapy, cryoretinopexy and segmental buckling. Her right visual acuity increased to 1.0. The association of retinitis pigmentosa sine pigmento, retrobulbar optic neuritis and rhegmatogenous retinal detachment, as demonstrated in our patient, may be uncommon.

Adolescent↗
PubMed2000

Melanocytoma of the left optic nerve head and right retrobulbar optic neuropathy compressed by a tuberculum sellae meningioma.

A 40-year-old woman had a highly pigmented, slightly elevated tumor on the left optic disc. She had no visual disturbance in the left eye. The tumor was stationary for 5 years. At age 45 years, she complained of decreased visual acuity in the right eye. Magnetic resonance imaging showed a right-shifted homogeneous lesion at the tuberculum sellae. Histopathologic study of the excised lesion revealed interlacing bundles of spindle-shaped fibroblast-like cells with whorl formation. We believe that a relationship between melanocytoma of the optic nerve head and a tuberculum sellae meningioma may exist rather than a chance occurrence, as previously suggested by others.

Adult↗
PubMed2000

Hydrocephalus in mice following X-irradiation at early gestational stage: possibly due to persistent deceleration of cell proliferation.

The pathogenesis of X-ray-induced congenital hydrocephalus was studied. Pregnant mice were irradiated at 1.4 Gy on gestational day 7 (G7). Four hours after irradiation, extensive cell death was evident in the neuroepithelium and underlying mesoderm of the head region, and proliferating cell nuclear antigen (PCNA)-immunoreactive cells almost disappeared. Embryos with thinner lamina terminalis of the telencephalon, when compared with that of the control, were found in the irradiated group on G9. As early as G11 in some irradiated embryos the telencephalic wall was thinner and lateral ventricles were larger than those of the control. The choroid invagination from the lamina terminalis began on G11 in the control brain, but not in the affected brain. During the following development, fetuses with readily apparent hydrocephalus were consistently found among irradiated fetuses. In these brains the brain mantle was thinner, the corpus striatum and thalamic regions were smaller, and lateral ventricles were larger than those of the control. Even on G11 and G13 the frequencies of PCNA-positive cells in the brain mantle and other brain regions were lower in the hydrocephalic brain than those of the control, suggesting a decelerated proliferation of successive cell generations following exposure to X-rays. The cerebral aqueduct was open in the hydrocephalic brain during the fetal period when the lateral ventricles were dilated. The head was vaulted after birth but the cerebral aqueduct was not completely occluded even in these animals. These findings suggested that cell death in the neuroepithelium followed by a persistent deceleration of neural cell proliferation, resulting in the hypoplasia of brain parenchyma with compensatory ventricular dilatation, is important for the establishment of hydrocephalus.

Animals↗
PubMed2000

Similarity between the effects of carbon-ion irradiation and X-irradiation on the development of rat brain.

The effects of carbon-ion irradiation and X-irradiation on the development of rat brain were compared. Twenty pregnant rats were injected with bromodeoxyuridine (BrdU) at 9 pm on day 18 of pregnancy and divided into five groups. Three hours after injection (day 19.0) one group was exposed to 290 MeV/u carbon-ion radiation by a single dose of 1.5 Gy. Other groups were exposed to X-radiation by 1.5, 2.0 or 2.5 Gy, or sham-treated, respectively. Fetuses were removed from one dam in each group 8 h after exposure and examined histologically. Extensive cell death was observed in the brain mantle from the irradiated groups. The cell death after 1.5 Gy carbon-ion irradiation was remarkably more extensive than that after 1.5 Gy X-irradiation, but comparable to that after 2.0 Gy or 2.5 Gy X-irradiation. The remaining rats were allowed to give birth and the offspring were sacrificed at 6 weeks of age. All of the irradiated offspring manifested microcephaly. The size of the brain mantle exposed to 1.5 Gy carbon-ion radiation was significantly smaller than that exposed to 1.5 Gy X-radiation and larger than that exposed to 2.5 Gy X-radiation. A histological examination of the cerebral cortex revealed that cortical layers II-IV were malformed. The defect by 1.5 Gy carbon-ion irradiation was more severe than that by the same dose of X-irradiation. Although the BrdU-incorporated neurons were greatly reduced in number in all irradiated groups, these cells reached the superficial area of the cortex. These findings indicated that the effects of both carbon-ion irradiation and X-irradiation on the development of rat brain are similar in character, and the effect of 1.5 Gy carbon-ion irradiation compares to that of 2.0-2.5 Gy X-irradiation.

Animals↗
PubMed2000

Whole mounted radical prostatectomy specimens do not increase detection of adverse pathological features.

PURPOSE: The optimal method to process radical prostatectomy specimens to maximize the detection of adverse pathological features is unclear and accurate staging is critical. We compare the ability of whole mounted sections to detect these features compared to partially submitted radical prostatectomy specimens. MATERIALS AND METHODS: A total of 93 consecutive radical prostatectomy specimens were processed as whole mounts. Tissue sections were analyzed and the pathological outcomes measured included Gleason score, surgical margin status, and presence or absence of extraprostatic tumor extension and/or seminal vesicle invasion. The pathological outcomes of the preceding cohort were compared to those of a similar cohort consisting of 554 men whose radical prostatectomy specimens were processed as partially submitted glands. RESULTS: A multivariate logistic regression analysis was performed to determine the effect of the method of tissue processing on the pathological outcomes. When considered alone or adjusted for various preoperative patient characteristics (prostate specific antigen, biopsy Gleason score and clinical stage), there were no significant differences in the ability of whole mounted specimens to detect the various outcomes compared to partially submitted specimens (all p >0.4). CONCLUSIONS: Whole mounted sampling of the radical prostatectomy specimen does not improve detection of adverse pathological features.

Histocytological Preparation Techniques↗
PubMed2000

Preferential adhesion of prostate cancer cells to bone is mediated by binding to bone marrow endothelial cells as compared to extracellular matrix components in vitro.

We have demonstrated previously that the preferential adhesion of prostate cancer cells to human bone marrow endothelial (HBME) cells may contribute to their preferential metastasis to bone. Although a subject of debate, it has been postulated that the endothelial cells of the bone marrow are fenestrated. It is unknown therefore whether prostate cancer cells adhere preferentially to the extracellular matrix (ECM) or the endothelial cells. It has also been demonstrated in other organ systems that the types of cell adhesion molecules on the surface of endothelial cells lining the organ microvasculature are determined, in part, by the ECM of the organ. We investigated how prostate cancer cell adhesion to HBME cells is affected by growing HBME cells on selected organ-derived ECM proteins in vitro. Growth of HBME cells and immortalized human aortic endothelial cells on bone, kidney, and placenta ECM proteins significantly increased their ability to bind PC-3 cells. This increased adhesion was not dose dependent and was not demonstrated with human dermal microvascular endothelial cells. Scanning electron microscopic analysis demonstrated that prostate cancer cells adhered directly to the endothelial cells and not to the underlying substrata. These results suggest that unidentified cell adhesion molecules are expressed or up-regulated on the apical surfaces of human aortic endothelial cells and HBME cells grown on bone, kidney, and placenta ECMs. These results also strongly demonstrate that the adhesion of prostate cancer cells to bone may be initiated by direct binding to endothelial cells rather than direct binding to exposed ECM components.

Bone Marrow Cells↗
PubMed1999

REP-1 gene mutations in Japanese patients with choroideremia.

BACKGROUND: Choroideremia (CHM) is an X-linked progressive dystrophy of the choroid, retinal pigment epithelium, and retina. Recently, the REP-1 gene was isolated and the causative mutations in the gene were detected in patients with CHM. In a previous study, we described a Japanese family with CHM who had a mutation in the REP-1 gene. In the present study, we performed extensive analysis of the REP-1 gene in patients with CHM from several institutions in Japan. METHODS: Twenty-six patients with CHM and 5 unaffected females from 22 independently ascertained families were examined. Exons 1-15 of the REP-1 gene were screened by single-strand conformation polymorphism. The DNA fragments suspected of any variations were directly sequenced. RESULTS: Fifteen different mutations, including one previously reported mutation, were detected in 18 families. In addition, carrier status was proven in four unaffected females found to be heterozygous for the mutant allele. CONCLUSIONS: Fifteen different mutations of the REP-1 gene were detected in 18 Japanese families. There were no hot spots for the mutations and no missense mutations. The results show that REP-1 gene defects cause CHM in Japanese patients, and the mutations in these Japanese patients differed from the mutations reported for CHM patients in Europe, Canada, and America except for R267X and 1313delTC. These findings suggest that the mutations occurred independently in the Japanese patients.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Pseudophakic cystoid macular edema treated with high-dose intravenous methylprednisolone.

PURPOSE: To evaluate the efficacy of high-dose methylprednisolone in the treatment of pseudophakic cystoid macular edema (CME). SETTING: University-affiliated hospital. METHODS: Four patients with pseudophakic CME who reported decreased visual acuities were treated with oral prednisolone (20 mg daily for 5 days), oral acetazolamide (500 mg daily for 5 days), and topical dexamethasone 0.1% and diclofenac 0.1% (4 times a day for 14 days). The CME did not resolve. Next, they were treated with high-dose (1000 mg daily) intravenous methylprednisolone for 3 days. RESULTS: In 3 of 4 eyes, the CME resolved and visual acuity improved. CONCLUSION: High-dose methylprednisolone may be effective in the treatment of pseudophakic CME.

Aged↗
PubMed1999

Cataract progression in patients with atopic dermatitis.

PURPOSE: To evaluate the possible causes of cataract progression in Japanese patients with atopic dermatitis. SETTING: Department of Ophthalmology, Toyama Medical and Pharmaceutical University, Toyama, Japan. METHODS: This prospective study comprised 41 patients (81 eyes) with atopic dermatitis. Cataract progression was determined by photographs and visual acuity results. Mean follow-up was 2.5 years (range 1.0 to 3.5 years). RESULTS: Of 41 patients, 10 (24.4%) had progression of cataract. Of 81 eyes, 10 (12.3%) had slow progression and 9 (11.1%), rapid. Cataract progression was not statistically significantly related to patient sex or severity of systemic skin lesions but was to facial skin lesions. Soft contact lens wear and eye rubbing were also correlated with cataract progression. CONCLUSION: Patients with facial atopic dermatitis, contact lenses, or both may rub their eyes more frequently than those with lesions on other body parts, increasing their risk of cataract progression.

Adolescent↗
PubMed1999

1147 del A mutation in the arrestin gene in Japanese patients with Oguchi disease.

We examined the sequence of the arrestin gene in two unrelated patients with Oguchi disease. A 35-year-old woman and a 72-year-old man underwent a complete ophthalmological examination, including evaluation of visual acuity and color vision, fundus examination, and electroretinography. A golden-yellow discoloration was observed in their fundi. After 30 minutes of dark adaptation, the discoloration in the fundus disappeared. A deletion of an adenine in codon 309 of exon 11 of the arrestin gene was identified in both patients. Mutations in the arrestin are common in Japanese patients with Oguchi disease.

Adult↗
PubMed1999

Secondary mutations of mitochondrial DNA in Japanese patients with Leber's hereditary optic neuropathy.

PURPOSE: Based on studies on the pathogenesis of Leber's hereditary optic neuropathy (LHON), mitochondrial DNA (mtDNA) mutations have been divided into two types: primary and secondary. Primary mutations at nucleotide positions (nt) 11778, 3460, and 14484 can each cause LHON. Secondary mutations may be simultaneously found in LHON patients with a primary mutation, may occur at higher frequency in LHON patients than in normal controls, and may play an additional role in the pathogenesis of LHON. We examined the frequencies of secondary mutations of mtDNA at nt3394, 7444, 9438, 9804, 13708, and 15257 in 19 Japanese patients with LHON associated with primary mutations and 108 normal controls. METHODS: Mutations were determined by restriction enzyme analysis or DNA sequencing using polymerase chain reaction (PCR) products. RESULTS: One patient with an nt11778 mutation also had an nt13708 mutation. Another patient with an nt3460 mutation also had an nt7444 mutation. During DNA sequencing of the PCR fragment harboring nt3394, three novel mutations in the ND1 gene (nt3316, 3496, and 3497 mutations) were found in three patients with an nt11778 mutation. The frequency of these mutations in 108 control subjects was studied further: one (0.9%) had an nt3394 mutation, none (0%) had an nt9804 mutation, one (0.9%) had an nt13708 mutation, two (1.9%) had nt3316 mutations, one (0.9%) had an nt3496 mutation, and two (1.9%) had nt3497 mutations. CONCLUSION: It is unlikely that the frequencies of secondary mutations in Japanese patients with LHON are higher than those in normal Japanese controls. It is possible that the mutations at nt3316, 3496, and 3497 are secondary mutations of LHON.

Adult↗
PubMed1999

Vogt-Koyanagi-Harada syndrome in an 11-year-old Boy.

An 11-year-old boy complained of headache, slight fever and decreased visual acuity. Intracameral cells and serous retinal detachment were found in both eyes. Pleocytosis was seen in the cerebrospinal fluid. Bilateral uveitis diminished rapidly in response to corticosteroid treatment. Depigmentation of the fundi developed several months later. We believe that Vogt-Koyanagi-Harada syndrome in a child, as demonstrated in our patient, may be uncommon.

Atropine↗
PubMed1999

Benign pleomorphic adenoma arising from the palpebral lobe of the lacrimal gland associated with elevated intraocular pressure.

A 46-year-old man complained of a painless mass in the left upper eyelid. At age 51 years, the patient complained of dull pain in the left eye and diplopia. His left intraocular pressure had increased to 33 mm Hg. No proptosis was noted. The nontender mass in the eyelid was palpable. Computed tomography showed a mass anterior to the orbital rim compressing the globe. The lesion was removed en bloc by a transconjunctival approach. Histopathologic examination of the excised mass showed myxomatous stroma and highly cellular epithelial areas. Postoperatively, the left intraocular pressure normalized. To our knowledge, benign pleomorphic adenomas arising from the palpebral lobe of the lacrimal gland associated with elevated intraocular pressure, as demonstrated in our patient, may be rare.

Adenoma, Pleomorphic↗
PubMed1999

Hypofluorescent spots on indocyanine green angiography at the recovery stage in multiple evanescent white dot syndrome.

PURPOSE: To evaluate the fundus lesions in a young woman. METHODS: Visual function, ophthalmoscopy, electrophysiology, fluorescein angiography, and indocyanine green angiography were performed. RESULTS: A 24-year-old woman had decreased visual acuity (0.2), granularity in the macula, and multiple yellow-white patches in the fundus, reduced a wave on electroretinography, hyperfluorescence on fluorescein angiography, and hypofluorescence on indocyanine green angiography in the left eye. When visual acuity improved to 1.0, the white dots disappeared ophthalmoscopically, and fluorescein angiography showed normal findings. Hypofluorescent spots were found, however, on indocyanine green angiography. CONCLUSION: It is possible that signs of multiple evanescent white dot syndrome may remain longer during examination by indocyanine green angiography than by visual function, ophthalmoscopy, or fluorescein angiography.

Adult↗