Biomedical subjects

Y Hayasaka

Publications and source records attributed to Y Hayasaka.

66 records · Page 4Linked to original sources

PubMedDate not supplied

Unilateral symptomatic elevation of intraocular pressure and prevention using a hyperosmotic agent during hemodialysis.

BACKGROUND: We report on a patient with unilateral elevation of intraocular pressure during hemodialysis. CASE: A 60-year-old man with unilateral exfoliative material complained of severe pain in the right eye during hemodialysis. OBSERVATIONS: The intraocular pressure (IOP) in the patient's right eye was 56 mm Hg, and increased repeatedly during hemodialysis. The IOP in his left eye remained within a normal range. Trabeculectomy failed to reduce the elevation of IOP in the right eye. Changes in plasma osmotic pressure during hemodialysis were marked when the IOP was elevated. The administration of a hyperosmotic agent prevented the elevation of IOP during hemodialysis. CONCLUSIONS: Physicians should be aware that elevation of IOP in patients with eyes with exfoliative material may occur during hemodialysis even after trabeculectomy. This can be prevented by administering a hyperosmotic agent during hemodialysis.

Diuretics, Osmotic↗

PubMedDate not supplied

Effect of topical betaxolol on acute rise of aqueous flare induced by prostaglandin E(2) in pigmented rabbits.

PURPOSE: To evaluate the effects of topical betaxolol on experimental ocular inflammation. METHODS: Transcorneal diffusion of 25 microg/mL (7.09 x 10(-2) mmol/L) of prostaglandin E(2) (PGE(2)), placed in a glass cylinder, was employed to induce aqueous flare elevation in pigmented rabbits. Betaxolol was administered topically before PGE(2) application. Aqueous flare was measured with a laser flare cell meter. RESULTS: Four-, two-, and one-time topical instillations of betaxolol inhibited the PGE(2)-induced aqueous flare elevation by 44% +/- 8%, 32 +/- 7%, and 8 +/- 6%(mean +/- SD), respectively. The inhibition of flare elevation was dependent on the number of betaxolol instillations. CONCLUSION: Topical betaxolol has an inhibitory effect on PGE(2)-induced aqueous flare elevation in rabbit eyes.

Acute Disease↗

PubMedDate not supplied

Extracorporeal hybridization of proximal renal tubular cells and an artificial membrane for the purpose of beta 2 microglobulin removal.

The present study was designed to develop a bioartificial kidney hybridized with LLC-PK1 cells for the purpose of beta 2microglobulin (B2M) removal. Cells were prepared in polystyrene culture wells; the bottom of each was covered with collagen fiber and the cells grown as monolayer cultures. Each well was inoculated with 1 ml cell suspensions with 0.0, 1.0 X 10(6), 2.0 X 10(6), or 4.0 X 10(6) cells/well. B2M was added to the culture system at a concentration of 80 micrograms/dl. Results were as follows: 1) Concentration of B2M in the supernatant of 4 X 10(6) cultivated LLC-PK1 cells was decreased from 79.32 +/- 2.41 micrograms/dl to 67.02 +/- 3.00 micrograms/dl (n = 6, p less than 0.01) at 2 hr; 2) Concentration of B2M in the supernatant of 1 X 10(6), 2 X 10(6), and 4 X 10(6) cultivated LLC-PK1 cells was 75.06 +/- 2.31 micrograms/dl (n = 6, p less than 0.05); 67.27 +/- 11.41 micrograms/dl (n = 6, p less than 0.001); and 67.02 +/- 3.00 micrograms/dl (n = 6, p less than 0.001), respectively, vs. 79.32 +/- 2.41 micrograms/dl in controls at 2 hr; 3) There was a significant positive correlation between the efficacy of B2M removal and cell number; and 4) These results suggested that it is possible to develop an artificial kidney hybridized with proximal tubular cells that possesses a high affinity for B2M removal.

Animals↗

PubMedDate not supplied

Prolongation of cardiac xenograft survival by double filtration plasmapheresis and ex vivo immunoadsorption.

A double filtration plasmapheresis (DFPP) technique and ex vivo immunoadsorption were applied to remove natural antibodies and avoid hyperacute rejection in discordant xenotransplantation. A swine heart was heterotopically transplanted into a dog's neck after DFPP and ex vivo immunoadsorption using a swine spleen or liver. Mean graft survival time was prolonged to 240 +/- 141 min in the group treated by combined DFPP and splenic adsorption, and 225 +/- 62 min in the group treated by combined DFPP and hepatic adsorption, whereas it was 9 +/- 5 min in the group without any treatment (p < 0.01). Mean removal rates of IgG and IgM were 85.5% and 93.3%, respectively. Anti-swine lymphocytotoxic antibodies and hemagglutination antibodies were also effectively removed. Deposits of canine IgM and C3 on the vascular endothelium of the graft were observed on immunofluorescence, which suggested that natural antibodies in the IgM fraction played an important role in xenohyperacute rejection.

Animals↗

PubMedDate not supplied

Changes in deviation following correction of hyperopia in children with fully refractive accommodative esotropia.

Changes in deviation may occur following the correction of hyperopia in children with accommodative esotropia. We analyzed possible factors involving the development of changes in deviation. We examined 49 children (23 boys and 26 girls) who had fully refractive accommodative esotropia at the age of 3 or 4 years. All children wore glasses to correct the fully cycloplegic refractive errors. At the age of 10 or 11 years, 28 (57.1%) of these children had good alignment, 12 (24.5%) developed partial accommodative esotropia and 9 (18.4%) developed consecutive exotropia. The age at onset of esotropia, age at initial visit, and refraction, deviation and presence of stereopsis, as determined by the Titmus test using a fly at the initial visit, were similar among the three groups. In the consecutive exotropia group, amblyopia at the initial visit was significantly higher (89%) than that of the good alignment group (50%). The age at the start of the correction, and the refraction, amblyopia and presence of fusion (10 or 11 years) were almost equal among the three groups. We conclude that some children with fully refractive accommodative esotropia associated with amblyopia at the age of 3 or 4 years may be predisposed to developing consecutive exotropia.

Accommodation, Ocular↗

PubMedDate not supplied

Bilateral angle closure glaucoma and visual loss precipitated by antidepressant and antianxiety agents in a patient with depression.

A 71-year-old woman with depression had been treated with an antidepressant (maprotiline) and antianxiety agents (clotiazepam and alprazolam). She had previously complained of ocular pain and blurred vision. However, thorough ocular examination was not performed at those times. On examination, visual acuity was no light perception OD and hand motion OS. Intraocular pressures were 33 mm Hg OU. Moderately dilated pupils, atrophic irises, shallow anterior chambers and closed angles were seen in both eyes. Despite treatment, her visual acuity decreased to no light perception bilaterally. Psychiatrists and ophthalmologists should be aware that antidepressants and antianxiety agents can precipitate angle closure glaucoma in susceptible eyes.

Adrenergic beta-Antagonists↗

PubMedDate not supplied

Effects of topical clonidine on prostaglandin-E(2)-induced aqueous flare elevation in pigmented rabbits.

We evaluated the role of topical clonidine on experimental ocular inflammation. Transcorneal diffusion of prostaglandin (PG) E(2), 7. 09 x 10(-2) mmol/l, with the use of a glass cylinder was employed to produce aqueous flare elevation in pigmented rabbits. Clonidine was topically administered and yohimbine was injected intravenously. Aqueous flare was measured with a laser flare cell meter. Topical instillation of 0.25% clonidine inhibited 89% of PGE(2)-induced aqueous flare elevation. Instillation of clonidine at 60 or 30 min before and 10 min after PGE(2) inhibited flare significantly. Pretreatment with intravenous yohimbine decreased the clonidine-induced inhibition of the flare elevation in a dose-dependent manner. It is possible that the anti-inflammatory action of topical clonidine may be mediated partly by alpha(2)-receptors.

Acute-Phase Reaction↗

PubMedDate not supplied

Serum methanol levels in subjects with or without optic nerve head disease.

We evaluated serum methanol levels in subjects with or without optic nerve head disease. Serum methanol levels were determined using gas chromatography in 71 patients with optic nerve head disease and in 127 subjects without optic nerve head disease. Their ages ranged from 17 to 89 years. Serum methanol levels in 127 subjects without optic nerve head disease ranged from 0.12 to 3.86 microg/ml (mean +/- standard deviation, 1.72 +/- 0.86 microg/ml). In the subjects without optic nerve head disease, the differences in the levels between those with cataract versus retinal detachment, men versus women, and between each age-group (50-80 years) were not significant. The methanol levels in patients with optic neuritis (n = 2), Wolfram syndrome (n = 1), Leber hereditary optic neuropathy at the late stage (n = 2), retinitis pigmentosa (n = 23), and primary open-angle glaucoma (n = 16) were less than 3.86 microg/ml. Methanol levels in 1 patient with Leber hereditary optic neuropathy at the acute stage was 5.28 microg/ml. Of 10 patients with primary angle-closure glaucoma, 1 had a slightly elevated level and 9 had levels less than 3.86 microg/ml. Of 17 patients with normal tension glaucoma, 5 had methanol levels higher than 3.86 microg/ml, and 12 patients had levels less than 3.86 microg/ml. The present study shows that serum methanol levels in subjects without optic nerve head disease ranged from 0.12 to 3.86 microg/ml and were much lower than the levels that produce acute ocular symptoms of methanol intoxication. It is possible that high serum methanol levels may play a part in the acute stage of Leber hereditary optic neuropathy and normal tension glaucoma in certain patients. It is unlikely that increased serum methanol levels participate in primary angle-closure glaucoma.

Adolescent↗

PubMedDate not supplied

Bilateral congenital macular coloboma in a boy with Down syndrome.

PURPOSE: To describe macular coloboma in Down syndrome. METHODS: A 12-year-old boy with Down syndrome underwent ophthalmologic examination. RESULTS: The patient had a circumscribed, round defect about 1 disc diameter, with bared sclera at the base and pigment clump at the macula in both fundi. His poor visual acuity was unchanged since childhood. The results of serum IgG and IgM titers for Toxoplasma gondii were negative. CONCLUSIONS: Congenital macular coloboma associated with Down syndrome, as demonstrated in our patient, may not have occurred by chance.

Child↗

PubMedDate not supplied

Ocular manifestations in patients with microscopic polyangiitis.

PURPOSE: To describe ocular manifestations in patients with microscopic polyangiitis. METHODS: Two patients with microscopic polyangiitis complained of ocular symptoms and underwent ophthalmologic examinations. RESULTS: An 83-year-old woman (Case 1) was diagnosed with microscopic polyangiitis, according to the general clinical findings and the presence of perinuclear pattern of antineutrophil cytoplasmic antibodies (P-ANCA). She had hypopyon iridocyclitis in the right eye and retinal cotton-wool spots in the left eye. The patient was treated with oral prednisolone and subconjunctival betamethasone. The hypopyon iridocyclitis and retinal cotton-wool spots responded. A 79-year-old man (Case 2) had bilateral scleritis. The diagnosis of microscopic polyangiitis was made based on general clinical findings and the presence of P-ANCA. Scleritis was reduced after corticosteroid treatment. CONCLUSIONS: Ophthalmologists should be aware that hypopyon iridocyclitis, cotton-wool spot, and scleritis could occur in patients with microscopic polyangiitis.

Aged↗

PubMedDate not supplied

Prolongation of cardiac xenograft function after reduction of natural antibodies using double filtration plasmapheresis.

A double filtration plasmapheresis (DFPP) technique was applied to selectively remove the natural antibodies in discordant xenotransplantation. A swine heart was heterotopically transplanted in a canine neck after two DFPP procedures during which 200 to 500 ml of plasma were replaced with the same amount of Hartman's solution containing 7% human albumin. Mean removal rate of IgC and IgM by DFPP ranged from 74.2 +/- 0.5 to 95.9 +/- 2.8%. The anti-swine lymphocytotoxic reaction of canine serum was decreased after DFPP but still remained in low titers. Mean graft survival time in the group treated by DFPP in which 1000 ml of plasma was totally replaced was prolonged to 107 +/- 47 min, while it was 9 +/- 5 min in the group without any treatment (p less than 0.01). Deposits of canine IgM and C3 on the vascular endothelium of the graft were observed on immunofluorescence, while there were no deposits of IgG. In conclusion, DFPP effectively removed the natural antibodies, resulting in prolongation of xenograft survival time. Immunofluorescence study suggested that natural IgM antibodies played an important role in this xeno-hyperacute rejection.

Animals↗

PubMedDate not supplied

Changes in electrical charge of leukocyte surface membranes during hemodialysis. Possible role in transient leukopenia.

Change in the electrical charge of leukocyte surface membranes during hemodialysis (HD) using a cellulose membrane was studied by examining adsorbability of leukocytes taken from patients undergoing HD to cation and anion exchange resins. Leukocytes of HD patients were well adsorbed to both anion and cation exchange resins, whereas normal leukocytes were only minimally adsorbed to a cation exchange resin, suggesting that the surface membranes of normal leukocytes were charged electronegatively. Adsorbability to anion exchange resin by patients' leukocytes taken from the venous limb of the HD circuit line 15 minutes after starting HD was significantly decreased when using a cellulosic membrane. This suggests that the decrease in electronegative leukocyte surface membrane charge, which may facilitate the attachment of leukocytes to electronegatively charged endothelial cell membranes, is the factor leading to leukopenia. Adsorbability to anion exchange resin by normal leukocytes incubated with plasma taken from HD patients 10 to 60 minutes after starting HD was increased, suggesting an increase in electronegatively charged substances in patients' plasma; these recombine with leukocyte surface membranes thereby increasing the electronegative charges of the leukocyte surface membranes and enabling subsequent release of leukocytes from endothelial cells, consistent with the transient nature of the leukopenia.

Adsorption↗