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Biomedical subjects

S Hayasaka

Publications and source records attributed to S Hayasaka.

At least 55 records · Page 3Linked to original sources
PubMed1999

Inhibitory effect of nilvadipine on disruption of blood-aqueous barrier induced by prostaglandin E2 application in pigmented rabbits: A morphologic study.

The purpose of the present study is to investigate the morphologic sites of breakdown in eyes pretreated with nilvadipine (a calcium channel blocker) that has been shown to inhibit the acute rise of aqueous flare induced by prostaglandin E2 (PGE2). Nilvadipine (100 microg/kg body weight) was injected intravenously in pigmented rabbits. Thirty minutes later, vehicle or PGE2 (10, 50 or 250 microg/ml) was applied on the cornea by use of a glass cylinder. Forty-five minutes later, the animals received horseradish peroxidase (HRP) intravenously and the eyes were enucleated. Distribution of HRP in the anterior segments was observed by electron microscopy. Without nilvadipine pretreatment, HRP was seen in the intercellular space of nonpigmented cells of the eyes treated with 50 microg/ml PGE2 and in the iris stroma of the eyes treated with 250 microg/ml PGE2. With nilvadipine pretreatment, HRP was not observed in these sites. Our results indicate that nilvadipine suppresses disruption of the different sites of the blood-aqueous barrier.

Animals↗
PubMed1999

Carotid artery fistula after cataract surgery.

To determine carotid cavernous fistula associated with choroidal detachment after cataract surgery. A 77-year-old woman underwent cataract surgery in both eyes. Postoperatively, proptosis and dilation of episcleral vessels in her left eye occurred and gradually increased. One month later, choroidal detachment developed in her left eye. Computed tomography showed an enlarged superior ophthalmic vein. Selected cerebral angiography showed fistulas between the megingeal branches of both the internal and external carotid arteries and the cavernous sinus. After the neurosurgical treatment, these symptoms disappeared. The development of carotid cavernous fistula after cataract surgery, as demonstrated in our patient, may be uncommon. [Ophthalmic Surg Lasers 1998;30:160-162.] Carotid cavernous fistula (CCF) is an abnormal communication between the internal carotid artery and the cavernous sinus. Ocular manifestation of the fistula includes proptosis, pulsation of the globe, orbital bruit, episcleral vein dilation, and chemosis. CCF is divided into spontaneous or traumatic by cause and direct or dural by angiographic findings. To our knowledge, CCF development after cataract surgery may be uncommon. We recently examined a patient with such a condition.

Aged↗
PubMed1999

Ultrastructural studies on the formation and distribution of lipid droplets in the lung capillary endothelial cells in patients with sarcoidosis.

BACKGROUND AND AIM OF THE WORK: We previously reported the presence of definite morphological alterations in the capillary endothelium of sarcoid lung. The aim of this study was to examine ultrastructural changes and distribution of lipid droplets in the endothelium of lung capillaries of patients with sarcoidosis. METHODS: Tissue specimens were obtained by transbronchial lung biopsy or open lung biopsy from 16 patients with sarcoidosis and 13 controls. Biopsies were evaluated by electron microscopy following lead citrate and uranyl acetate staining. RESULTS: Typical lipid droplets were observed in pulmonary capillaries of 11 out of 16 sarcoid patients (69%); the droplet frequency was higher in sarcoid patients than in control specimens. Lipid droplets were characterized by biphasic density: most droplets contained eccentrically located vacuoles (saturated fatty acids) others were characterized by low density areas (unsaturated fatty acids). Biphasic droplets were covered by large lysosomal granules and were mainly distributed in the endothelium and pericytes. Interestingly, in the latter, vacuoles increased in size while small amounts of lysosomal granules were detectable. CONCLUSION: Our findings suggest that biphasic droplets increase in number in pulmonary capillaries of patients with sarcoidosis with a characteristic distribution pattern from the endothelium to pericytes.

Adult↗
PubMed1999

Management of traumatic cyclodialysis cleft associated with ocular hypotony.

BACKGROUND AND OBJECTIVE: To evaluate the efficacy of direct cyclopexy for treatment of traumatic cyclodialysis cleft associated with ocular hypotony. PATIENTS AND METHODS: Eyes with traumatic cyclodialysis cleft were treated with direct cyclopexy or 1.0% atropine eyedrop. RESULTS: Five eyes with a large cyclodialysis cleft were treated with direct cyclopexy. Postoperatively, these eyes obtained normal intraocular pressure. Four of the 5 eyes had good visual acuity, and 1 eye that had preoperative subretinal hemorrhage in the macula had poor visual acuity. Of the 3 eyes treated with 1.0% atropine eyedrops, 1 had good visual acuity, and 2 with retinal folds had fairly good and poor visual acuity. CONCLUSION: The present study showed that direct cyclopexy is useful for the treatment of traumatic cyclodialysis cleft associated with ocular hypotony, and that the cyclodialysis should be surgically treated before irreversible retinal folds develop.

Adolescent↗
PubMed1999

[Primary Sjögren's syndrome with lymphocytic interstitial pneumonia and pulmonary multiple cystic lesions].

We report a case of primary Sjögren's syndrome with lymphocytic interstitial pneumonia and multiple cystic lesions. The patient was a 64-year-old woman. Abnormal chest shadows were detected by x-ray and computed tomographic (CT) examinations. The patient had no family history of disease and had never smoked. She had complained of dryness in the eyes and mouth for about 10 years. Laboratory tests were positive for anti-nuclear antigen, anti-SS-A antigen, and anti-SS-B antigen. Sialography revealed marked destruction of the salivary glands, yielding a diagnosis of Sjögren's syndrome. Chest X-ray films and CT scans showed multiple cystic lesions in both lungs, measuring from a few mm to 3 cm in diameter, as well as fine centrilobular nodules. Slight anemia and hyper gamma globlinemia were also detected. Pulmonary function tests showed mild obstructive disturbance. Bronchoalveolar lavage analysis disclosed an elevated lymphocytic fraction (28.6%), but transbronchial lung biopsy provided no adequate specimens for diagnosis. Thoracoscopic lung biopsy specimens demonstrated marked infiltration of lymphocytes and histiocytes through the interstitium of alveolar walls and peri-bronchovascular sheath, with some lymphoid follicles. The overall appearance was compatible with lymphocytic interstitial pneumonia. The cysts themselves were nonspecific, and no cellular infiltration was noted in the cyst walls. Because of the predominantly peribronchial distribution of the lesions, we suspected that the cysts were formed by the check valve mechanism. However, no definitive evidence was obtained.

Cysts↗
PubMed1999

A comparison of effects between accelerated heavy ion irradiation and X-irradiation on the development of rat cerebellum.

The purpose of this experiment is to compare the effects of 290 MeV/u carbon-ion irradiation and X-irradiation on the development of rat cerebellum. Pregnant rats were exposed to carbon-ion beams at a single dose of 1.5 Gy on day 19.0 of gestation. Other groups of pregnant rats were exposed to X-rays on day 19.0 at single doses of 1.5, 2.0 and 2.5 Gy. Their fetuses were removed 8 hr after exposure, and an acute effect examined microscopically for cell death in the external granular layer of the cerebellum. Other dams were allowed to give birth and rear their litters. The offspring were sacrificed at 6 weeks of age, and their cerebella were examined for foliar malformation. The results showed that the effect of 1.5 Gy carbon-ion irradiation on the development of cerebellum was stronger than that of 1.5 Gy X-irradiation and similar to 2.0-2.5 Gy X-irradiation.

Animals↗
PubMed1998

Mitochondrial DNA mutations in Japanese patients with optic neuropathy unassociated with a mutation at nucleotide position 11,778.

We examined for mitochondrial DNA (mtDNA) mutations at nucleotide positions(nt) 3460, 14,484, 9438, 9804, and 15,257 in ten Japanese patients with idiopathic optic neuropathy unassociated with a mutation at nt11,778. The mtDNAs were amplified by polymerase chain reaction (PCR), the products were digested with restriction enzymes, and the sizes of the fragments were analyzed on 8% polyacrylamide gel. Of the ten patients, one had an mtDNA mutation at nt3460 and another patient had a mutation at nt14,484. We suggest that mtDNA mutations in Japanese patients with optic neuropathy unassociated with a mutation at nt11,778 should be further investigated.

Adolescent↗
PubMed1998

Acute comitant esotropia in a boy with head trauma and convulsions receiving carbamazepine.

We examined an 11-year-old boy who complained of acute onset of diplopia. The patient had head trauma and postsurgical convulsions and had been treated with carbamazepine. Diplopia developed after the dose of carbamazepine was increased to 700 mg/day. On examination, comitant esotropia and lateral gaze nystagmus were found. These disorders disappeared after carbamazepine was decreased to 400 mg/day. We believe that acute comitant esotropia and lateral gaze nystagmus may have been precipitated by head trauma and carbamazepine in our patient.

Acute Disease↗
PubMed1998

Decreased visual acuity and Diplopia in a patient with münchausen syndrome.

A 20-year-old woman complained of decreased visual acuity in her left eye and diplopia. She had visited several hospitals previously. On examination, her left visual acuity varied, and her squint angle also changed. No organic disorders that could have caused the symptoms were noted. She complained of edema of her left arm. On admission to another hospital, her arm was found bound tightly with tape. She wanted surgery to correct her esotropia but did not expect to improve her quality of life by having it done. We believe that our patient may have Münchausen syndrome and that the decreased visual acuity and diplopia may be a rare association with the syndrome.

Adult↗
PubMed1998

Idiopathic sclerosing inflammation of the upper eyelid.

Idiopathic sclerosing inflammation has commonly been found in the diffuse orbital tissues. We report the inflammation of the right upper eyelid in a 65-year-old man. Computed tomography and magnetic resonance imaging showed a diffuse mass localized only in the right upper eyelid. Histologic study of the excised specimen revealed dense collagenous tissue with sparse infiltration of mixed inflammatory cells. Immunohistochemical study showed that the inflammatory cells were largely composed of T cells (UCHL-1), histiocytes (PG-M1) and scattered plasma cells (immunoglobulins). No L26-positive B cells were found. We believe that idiopathic sclerosing inflammation of the upper eyelid, as demonstrated in our patient, may be rare.

Aged↗
PubMed1998

Intracameral levels of intravenously injected fluorescein, cefmenoxime, and chloramphenicol in the prostaglandin E2-administered eyes of albino rabbits.

We evaluated the effects of inflammation and physicochemical nature of selected agents on the intracameral levels of intravenously injected drugs in albino rabbits. Transcorneal diffusion of prostaglandin E2 (10, 50 or 250 micrograms/ml) using a glass cylinder was used to produce inflammation of the anterior segment in the right eyes. As a control, a vehicle was applied to the left cornea. Immediately, 2, 5, or 11 h after prostaglandin E2 administration, a mixed solution of fluorescein, cefmenoxime, and chloramphenicol (50 mg each/kg body weight) was injected intravenously. One hour after injection of the drugs, the primary aqueous humor was withdrawn. The intracameral levels of protein and these drugs after prostaglandin E2 administration increased at 1 h in a dose-dependent manner. These levels then gradually decreased. One hour after prostaglandin E2 administration, the intracameral levels of protein and these drugs in the prostaglandin E2-administered eyes were significantly higher than those in the vehicle-administered eyes, except chloramphenicol after administration of 10 micrograms/ml prostaglandin E2. Our findings indicate that the intracameral levels of intravenously administered drugs are altered not only by the severity of inflammation but also by the properties of drugs.

Animals↗
PubMed1998

Nilvadipine inhibits acute rise of aqueous flare and intraocular pressure induced by prostaglandin E2 in pigmented rabbits.

To evaluate the possible role of calcium channel blocker on changes in aqueous flare and intraocular pressure induced by prostaglandin E2 (PGE2) in pigmented rabbits, we examined the effects of nilvadipine and nicardipine (calcium channel blockers). PGE2, 25 micrograms/ml, was administered using a glass cylinder. Nilvadipine or nicardipine was injected intravenously. Aqueous flare was measured by a laser flare cell meter. Intraocular pressure was measured by a noncontact tonometer. After administration of PGE2, aqueous flare and intraocular pressure increased and then decreased. Increased flare and elevated intraocular pressure following PGE2 administration were inhibited by nilvadipine in a dose-dependent manner (5-500 micrograms/kg body weight). These responses were inhibited only slightly by nicardipine at the same concentration. Nilvadipine injected 30 min before PGE2 application inhibited the increase maximally. The inhibitory effect was found on days 1, 3, 5, and 7 by daily administration of nilvadipine. A good correlation between the inhibition of intraocular pressure and the inhibition of increased flare by nilvadipine was found. We believe that Ca2+, or calcium channel blocker-related substances may be involved in the mechanism of PGE2-induced elevation of aqueous flare and intraocular pressure in the pigmented rabbit.

Animals↗
PubMed1998

123I-MIBG SPECT of Merkel cell carcinoma.

131I-MIBG may be useful in the detection of neuroendocrine tumours. Merkel cell carcinoma is a neuroendocrine tumour of the skin. We evaluated a patient with Merkel cell carcinoma using 123I-MIBG single photon emission computed tomography (SPECT) which demonstrated tumour accumulation of the radiotracer in the right eyelid. This result suggests that 123I-MIBG SPECT may be useful in the evaluation of Merkel cell carcinoma.

3-Iodobenzylguanidine↗
PubMed1998

Disturbed Purkinje cell migration due to reduced expression of Reelin by X-irradiation in developing rat cerebellum.

The major histogenetic events of the rat cerebellum take place in the early postnatal days. During this period, precursors of microneurons, such as granule cells, form the external granular layer (EGL), extend over the surface of the primordial cerebellum, and actively proliferate. Postmitotic granule cells leave the EOL and migrate to the internal granular layer (IGL). On the other hand, guided by radial glial fibers, immature Purkinje cells migrate from the ventricular zone of the fourth ventricle and settle in the Purkinje cell plate with thickness of several cells. Various cell adhesion molecules are involved in the interaction between the migratory immature Purkinje cells and processes of the radial glia as the basis for contact guidance. The second process is the formation of immature Purkinje cells to the monolayer. This process takes place at the first week after birth of the rat and cell adhesion molecules such as neural cell adhesion molecule (NCAM), fibronectin, tenascin and Reelin are also suggested to play an important role for the cell patterning. When rat fetuses are exposed to X-radiation in the last gestation period, abnormal foliation of the cerebellum develops with ectopic Purkinje cells. The molecular mechanism that contributes to abnormal migration of Purkinje cells and foliar malformation induced by X-irradiation in the cerebellum are not yet clear. This study was undertaken to elucidate the mechanisms of ectopic Purkinje cell formation by examining the expression of cell adhesion molecules.

Animals↗
PubMed1998

Congenital hydrocephalus caused by exposure to low level X-radiation at early gestational stage in mice.

Hydrocephalus is a severe and often lethal birth defect in humans resulting from excess accumulation off cerebrospinal fluid (CSF) in the cranial vault, accompanied by enlargement of the head, prominence of the forehead and atrophy of the brain. A wide variety of teratogenic procedures have been used to obtain congenital hydrocephalus in laboratory animals. Radiation, infections, trypan blue, hypervitaminosis A, salisylates and nutritional deficiencies were considered as the teratogens. Several investigators induced congenital hydrocephalus following irradiation of pregnant animals. The purpose off this study is to elucidate the pathogenesis off congenital hydrocephalus induced by X-irradiation in mice. Since the sensitive period for malformations produced by X-radiation in mice ranges from gestational day 7 (G7) to Gl3.

Abnormalities, Radiation-Induced↗
PubMed1998

Dose response relationship of disturbed migration of Purkinje cells in the cerebellum due to X-irradiation.

Pregnant rats were exposed to 2.0, 2.25 or 2.5 Gy X-irradiation on gestation day 21. Pups were sacrificed 12 hr after exposure, and on postnatal day 5 (P5), P7 and P9. Their cerebella were observed immunohistochemically using anti-inositol 1,4,5 triphosphate (IP3) receptor antibody to identify Purkinje cells. These cells were disturbed to migrate and remained in the internal granular layer and white matter of the cerebellum. They had short dendrites, and some showed an abnormal direction of dendrites in rats exposed to 2.25 or 2.5 Gy. Alignment of Purkinje cells was also disturbed when examined either on P5, P7 or P9 especially by doses of 2.25 and 2.5 Gy. There was a relationship between X-ray doses and the number of cells piling up in the Purkinje cell layer of the cerebellum. The dose-response relationship with the number of ectopic Purkinje cells was noted in the anterior lobes of the cerebellum.

Animals↗