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Biomedical subjects

F Shiraga

Publications and source records attributed to F Shiraga.

33 records · Page 2Linked to original sources
PubMed1993

Photoreceptor outer segments in the aqueous humor of patients with atopic dermatitis and retinal detachment.

We examined the aqueous humor by electron microscopy of four patients with atopic dermatitis and retinal detachment. All the patients had a moderate number of cells in the aqueous humor. Cataract impaired fundus visualization except for one patient with aphakia. A flat retinal detachment involved a wide area detected by echography. The intraocular pressure in the eyes with retinal detachment demonstrated a marked diurnal fluctuation compared with that of the fellow eye. The aqueous cells consisted predominantly of photoreceptor outer segments. This finding does not support the theory that aqueous cells in atopic dermatitis are of inflammatory origin. Photoreceptor outer segments in aqueous humor are indicative of rhegmatogenous retinal detachment in patients with atopic dermatitis.

Adolescent↗
PubMed1990

Retinal pigment epithelial tear in reactive lymphoid hyperplasia of uvea.

A 76-year-old patient developed cystic exudative retinal detachment with many yellowish subretinal precipitates and a large retinal pigment epithelial (RPE) tear in midperiphery of the right eye in the course of polyclonal hypergammaglobulinemia. The left eye showed localized RPE detachment in the posterior pole which gradually extended. Systemic steroid administration reduced the subretinal precipitates to some extent, but suspicion of malignancy led to enucleation of the right eye after unsuccessful diagnostic vitrectomy. A histopathological study revealed massive infiltration of the uvea with plasma cells and small lymphocytes but no abnormal cells. This is the first report to show the association of an RPE tear with reactive lymphoid hyperplasia of the uvea.

Aged↗
PubMed1990

[A case of crystalline retinopathy with crystalline deposits in the cornea].

We experienced a case of crystalline retinopathy with crystalline deposits in the cornea and the limbal conjunctiva, and performed histological studies of the cornea, conjunctiva and peripheral blood cells. The patient was a 45-year-old man who had no abnormality in hematological studies and urinalysis. In the fundus diffuse atrophy of the retinal pigment epithelium and patchy foci of choroidal atrophy were observed, and sparkling yellowish-white spots were scattered, chiefly in the posterior region. Fluorescein angiography showed neither hyperfluorescence nor hypofluorescence at these spots. In the marginal cornea and the limbal conjunctiva crystalline deposits were observed. Histological findings by light microscopy and electron microscopy revealed sparse degeneration of epithelial cells in both the cornea and the limbal conjunctiva. But no substances corresponding to crystalline deposits could be identified. Inclusion bodies were detected including clefts in circulating lymphocytes and eosinophils. The inclusion bodies suggest that crystalline retinopathy results from a systemic metabolic abnormality.

Conjunctiva↗
PubMed1988

Keratomalacia in a child with familial hypo-retinol-binding proteinemia.

Retinol-binding protein (RBP) is a plasma protein with a molecular weight of 21,000 synthesized in the hepatocytes, binding with retinol (vitamin A), and transporting retinol to peripheral tissues. Keratomalacia is caused by a deficiency of vitamin A itself and/or protein-calorie malnutrition. In the latter condition, production of RBP is inhibited. We report herein familial hypo-retinol-binding proteinemia in a child aged 19 months who developed keratomalacia during measles infection in spite of good nourishment. To the best of our knowledge this is the first description of such a case. The patient, her sister and mother showed persistent low levels, about half the normal levels, of retinol and RBP which were unresponsive to oral vitamin A and protein-rich diet. They had normal liver function tests, normal serum levels of other proteins and fat-soluble vitamins and lipids. This hypo-retinol-binding proteinemia was thought to predispose the child to develop keratomalacia during measles. Family members would be heterozygous with one normal RBP gene and one defective RBP gene.

Child↗
PubMedDate not supplied

Scleral infolding combined with vitrectomy and gas tamponade for retinal detachment with macular holes in highly myopic eyes.

PURPOSE: To describe the effectiveness of a surgical procedure, scleral infolding combined with vitrectomy and gas tamponade, for retinal detachment caused by macular holes in highly myopic eyes. METHODS: In a pilot study, scleral infolding was performed in 5 patients with macular holes, who were selected from 10 consecutive highly myopic patients with retinal detachment caused by macular holes (8 patients) or extramacular posterior-pole holes (2 patients), treated during 1 year at Okayama University Hospital. The patients were all women, 48-77 years of age (mean = 63.4 years), who had been followed-up for 1-2 years. Selection criteria for scleral infolding were either second surgeries for reopening of macular holes (2 patients) or residual retinal detachment around macular holes after complete fluid-air exchange with drainage of subretinal fluid at the initial surgery (3 patients). Following vitrectomy and complete epiretinal membrane removal in the posterior pole, the sclera was shortened by infolding on the temporal side. Three mattress sutures with 5-0 Dacron in each quadrant, 6 sutures in total, were placed at a 7-mm anteroposterior interval with posterior sutures located as deep as possible, near vortex veins. Fluid-gas exchange was then done, with or without endophotocoagulation applied around macular holes. RESULTS: After scleral infolding, macular holes were closed, and the retina was totally attached in all 5 patients. The final visual acuity ranged from 20/2000 to 20/70. CONCLUSION: Scleral infolding is a simple and effective procedure for treating retinal detachment with macular holes in highly myopic eyes and could be used as an optional procedure of reoperation for a failed initial vitrectomy.

Aged↗
PubMedDate not supplied

TIMP-1 production by bovine retinal pigment epithelial cells increases in response to cyclic mechanical stretch.

PURPOSE: The effect of mechanical stretch was examined on cultured retinal pigment epithelial (RPE) cells in order to observe changes in their production of tissue inhibitor of metalloproteinase-1 (TIMP-1) and vascular endothelial growth factor (VEGF) in response to physiological strain. METHODS: Bovine RPE cells in near-confluent culture were exposed to mechanical stretch of the bottom of a 6-cm petri dish at the maximum magnitude of 4500 microstrain and at a cycle of 30 seconds for 72 hours. TIMP-1 and VEGF levels in the medium following 24, 48, and 72 hours of cyclic stretch were measured by enzyme immunoassay. RESULTS: The growth of RPE cells during the 72-hour period of stretching did not show a significant difference from that of nonstretched control cells. RPE cells in the stretched group produced a significantly larger amount of TIMP-1 at 48 and 72 hours after stretch, compared with nonstretched control (P =.044 and P =.027, respectively, Student t-test). The levels of VEGF produced by RPE cells were not significantly different between the stretched group and nonstretched control group. CONCLUSIONS: The secretion of TIMP-1 by bovine RPE cells was enhanced by cyclic mechanical stretch. Mechanical strain is one factor in regulating the secretion of TIMP-1 by RPE cells.

Animals↗
PubMedDate not supplied

TIMP-1 and TIMP-2 levels in vitreous and subretinal fluid.

To understand the role of tissue inhibitors of metalloproteinase-1 and -2 (TIMP-1 and TIMP-2) in intraocular diseases, levels of TIMP-1 and TIMP-2 were measured by enzyme immunoassay in 47 patients with various ocular diseases: in subretinal fluid of 7 patients with rhegmatogenous retinal detachment and in vitreous of 12 patients with proliferative diabetic retinopathy, 4 with proliferative vitreoretinopathy, 2 with vitreous hemorrhage due to branch retinal vein occlusion, 12 with idiopathic macular hole, 3 with retinal detachment due to high-myopic macular hole, 4 with macular epiretinal membrane, and 3 with choroidal neovascular membrane due to age-related macular degeneration. TIMP-1 levels were significantly higher in subretinal fluid than in vitreous fluid with any diseases (P < 0.0001, Mann-Whitney U test). TIMP-1 levels in vitreous fluid of the eyes with proliferative diabetic retinopathy and proliferative vitreoretinopathy were higher than those in vitreous with other diseases (P < 0.0001). In contrast, TIMP-2 levels were not elevated in the subretinal fluid and vitreous. TIMP-1, but not TIMP-2, was secreted into the subretinal space in rhegmatogenous retinal detachment, and also into the vitreous in eyes with proliferative disease, suggesting that TIMP-1 would play a specific role in the process of these diseases.

Biomarkers↗
PubMedDate not supplied

Clinical and angiographic characteristics of retinal manifestations in cat scratch disease.

PURPOSE: To elucidate clinical and angiographic features of retinal manifestations in cat scratch disease. METHODS: Clinical characteristics as well as fluorescein and indocyanine green (ICG) angiographic features were reviewed in 4 consecutive patients with retinal manifestations caused by serologically confirmed cat scratch disease. RESULTS: A subretinal to intraretinal granuloma at the upper margin of the optic disc was found in 3 patients, while 1 patient developed subretinal to intraretinal granuloma in the midperiphery with serous retinal detachment. Fluorescein angiography revealed the abnormal vascular network of the peripapillary granuloma in the early phase followed by its dye leakage toward the late phase. Indocyanine green angiography demonstrated more clearly the abnormal vascular network with its minimal dye leakage than did fluorescein angiography. In contrast, only the late dye leakage was noted from granuloma of the midperipheral fundus by fluorescein angiography in one patient. Indocyanine green angiography detected no choroidal lesions other than the retinal lesions delineated by fluorescein angiography. The granulomas disappeared in response to a 4-week course of sulfamethoxazole-trimethoprim combined with steroids. CONCLUSIONS: Granuloma with abnormal vascular network as revealed by fluorescein and ICG angiography is characteristic of retinal manifestations in cat scratch disease.

Angiography↗
PubMedDate not supplied

TIMP-1 production by human scleral fibroblast decreases in response to cyclic mechanical stretching.

PURPOSE: The effect of mechanical stretching was examined on cultured scleral fibroblasts of the human eye in order to observe changes in their production of TIMP (tissue inhibitor of metalloproteinase)-1, MMP (matrix metalloproteinase)-1 and -2 in response to physiological strain. METHODS: Human scleral fibroblasts were cultured from scleral tissue resected during foveal translocation surgery. The fibroblasts in near confluency were exposed to mechanical stretching of the bottom of a 6-cm Petri dish at the maximum magnitude of 4500 microstrain and at a cycle of 30 s for 72 h. TIMP-1, MMP-1 and MMP-2 levels in the medium following 24, 48 and 72 h of cyclic stretching were measured by enzyme immunoassay. RESULTS: The growth of scleral fibroblasts during the 72-hour period of stretching did not show a significant difference from that of non-stretched control fibroblasts. Scleral fibroblasts in the stretched group produced a significantly smaller amount of TIMP-1 at 72 h after stretching, compared with nonstretched control (p = 0.0353, Student t-test). The levels of MMP-1 and MMP-2 produced by scleral fibroblasts were not significantly different between the stretched group and nonstretched group. CONCLUSION: The production of TIMP-1 by human scleral fibroblasts was suppressed by cyclic mechanical stretching. Mechanical strain would be one factor to regulate the homeostasis of extracellular matrix in the sclera.

Aged↗
PubMedDate not supplied

Retinal cells produce TIMP-1 and TIMP-2 in response to cyclic mechanical stretching.

PURPOSE: Tissue inhibitors of metalloproteinases (TIMPs) are crucial for the maintenance of retinal extracellular matrix such as interphotoreceptor matrix and internal limiting membrane. This study is to examine whether retinal cells respond to mechanical stretching and produce TIMPs. METHODS: Chick retinal adherent cells in near confluency were exposed to mechanical stretching of the bottom of a 6-cm Petri dish at the maximum magnitude of 4,500 microstrain and at a cycle of 30 s for 72 h. TIMP-1 and TIMP-2 levels in the medium at 24, 48 and 72 h after the beginning of stretching were measured by enzyme immunoassay, and their expression was examined by immunohistochemistry. RESULTS: The number of retinal cells during the 72-hour period of stretching did not change significantly both in the stretched group and in the nonstretched control group. Retinal cells in the stretched group produced significantly larger amounts of TIMP-1 and TIMP-2 at 48 h after stretching, compared with nonstretched controls (p = 0.0163 and p = 0.047, respectively, Mann-Whitney U test). Immunohistochemically, a large part of retinal cells in nonstretched Petri dishes was positive for glial fibrillary acidic protein, indicative of glial cells, while some small foci of cells were positive for neuron-specific enolase, indicative of neurons. Fluorescent double labeling demonstrated that both glial cells and neurons were positive for TIMP-1 and TIMP-2. CONCLUSION: Chick retinal cells, most of which were glial cells mixed with a small number of neurons, produced TIMP-1 and TIMP-2. Their production was enhanced by cyclic mechanical stretching.

Animals↗
PubMedDate not supplied

Aqueous flare elevation in the fellow eye after vitrectomy.

OBJECTIVE: Aqueous flare elevation has been shown to occur in the fellow eye after cataract surgery. This study tests whether such subclinical sympathetic reaction also takes place after vitrectomy. PATIENTS AND METHODS: In a prospective clinical study, preoperative and postoperative 2-week levels of aqueous flare in the fellow eyes of 38 patients who underwent vitrectomy during a 6-month period were measured with a laser flare-cell meter. RESULTS: Aqueous flare levels in the fellow eyes 2 weeks after vitrectomy (mean, 15.70 photon counts/millisecond) were significantly higher than preoperative flare levels (mean, 11.78 photon counts/millisecond, Wilcoxon's signed rank test, P = 0.04). CONCLUSION: This study demonstrated that subclinical sympathetic reaction did occur in the fellow eyes after vitrectomy.

Adult↗