Search PubMed⌕ Search

Biomedical subjects

T Hida

Publications and source records attributed to T Hida.

At least 127 records · Page 7Linked to original sources
PubMed1988

Tumor-promoting phorbol esters induce angiogenesis in vivo.

It has been hypothesized that tumor growth is dependent on the concomitant growth of its vascular supply, and thus agents that stimulate angiogenesis may help support tumor growth. Phorbol esters are potent tumor promoters that induce a variety of biochemical effects in cells, including activation of protein kinase C. The specific mechanisms responsible for tumor promotion by phorbol esters are unknown. The objective of this study was to determine whether the tumor-promoting phorbol esters can induce vascular growth. Phorbol esters were tested for their ability to stimulate angiogenesis in vivo using the chick chorioallantoic membrane and rabbit cornea assays. The active tumor promoters 12-O-tetradecanoyl phorbol-13-acetate and phorbol 12,13-didecanoate, which activate protein kinase C, were found to stimulate angiogenesis in a dose-dependent manner. In contrast, 4 alpha-phorbol 12,13-didecanoate, which is inactive as a tumor promoter and does not activate protein kinase C, did not stimulate angiogenesis. Phorbol esters may be indirect angiogenic factors, since no mitogenic effect on bovine capillary endothelial cells in culture could be detected. The results demonstrate that the tumor-promoting activity of phorbol esters may, in part, be secondary to stimulation of neovascularization to support tumor growth and suggest a role for the activation of protein kinase C in this process.

Allantois↗
PubMed1987

Clinical features of a newly recognized type of lattice corneal dystrophy.

We examined five patients with an undescribed type of lattice corneal dystrophy. All patients were in the seventh to ninth decades of life and had developed decreasing vision late in life. None of the patients had suffered from recurrent epithelial erosions, there was no overt evidence of systemic amyloidosis, and the lattice lines were much thicker than those usually observed in lattice corneal dystrophy types I and II. Available pedigree data from two families of three patients indicated that the corneal disorder affected several siblings but not the parents or offspring. Two patients had no affected family members. There was no known consanguinity in any of the four families.

Adult↗
PubMed1987

Histopathologic and immunochemical features of lattice corneal dystrophy type III.

We examined seven corneas from five patients with a new form of lattice corneal dystrophy (designated lattice corneal dystrophy type III) by light and electron microscopy. Numerous amyloid deposits were scattered throughout the corneal stroma, some of which were much larger than those usually observed in either lattice corneal dystrophy type I or II; these were located predominantly midway between the epithelium and the endothelium. Image analysis disclosed that the cross-sectional size of the large stromal amyloid deposits was significantly greater than those in age-matched patients with lattice corneal dystrophy type I. All patients had a discontinuous band of amyloid (15 to 25 micron wide) in the superficial stroma beneath Bowman's layer, which usually had only one or two small disruptions. Descemet's membrane and the endothelium were normal. The stromal deposits, which were composed of 10-nm diameter fibrils typical of amyloid, stained positively with Congo red after the histologic sections were pretreated with dilute potassium permanganate. Immunohistochemical studies on formalin-fixed, paraffin-embedded tissue indicated that only some deposits reacted weakly with antibodies to amyloid protein AA. The deposits stained positively with antibodies to protein AP and negatively with antibodies to kappa and lambda immunoglobulin light chains.

Amyloid↗
PubMed1987

Transvitreal cyanoacrylate retinopexy in the management of complicated retinal detachment.

We used transvitreally delivered cyanoacrylate tissue adhesive to seal retinal breaks in 25 selected patients undergoing vitreous surgery for complicated retinal detachment. With a minimum follow-up period of six months, all but one retinal hole remained closed. Complete retinal reattachment posterior to the encircling buckle was achieved in 18 of 25 eyes (72%). In ten of 25 eyes (40%) the final visual acuity was 5/200 or better.

Adolescent↗
PubMed1987

Experimental transvitreal cyanoacrylate retinopexy in a primate model.

We evaluated the use of transvitreal cyanoacrylate retinopexy in the treatment of experimental rhegmatogenous retinal detachment during vitreous surgery in the cynomolgus monkey. The chorioretinal adhesions produced with cyanoacrylate tissue adhesive as compared with those produced by transscleral retinal cryopexy were more rapid in onset as well as stronger. To test the efficacy of cyanoacrylate retinopexy further, a 360-degree peripheral retinectomy was created in five eyes with circumferential cyanoacrylate application to the posterior retinal edge. The cyanoacrylate retinopexy did not prevent the development of proliferative vitreoretinopathy with traction retinal detachment, but in three of the eyes the tissue adhesive continued to maintain retinal apposition to the retinal pigment epithelium at the retinotomy edge. Histologic examination of the retinas disclosed a foreign body reaction adjacent to the cyanoacrylate sites, but there was no evidence of any distant effects caused by the tissue adhesive.

Animals↗
PubMed1987

Improvement in efficacy of corticosteroid therapy in an animal model of proliferative vitreoretinopathy by pretreatment.

Intraocular injection of the corticosteroid triamcinolone acetonide reduces the incidence of retinal detachment in rabbit eyes injected with tissue-cultured fibroblasts. When the steroid was injected simultaneously with the cells, a reduction of retinal detachment from 93% (control) to 75% (treated) was achieved on day 28. When the steroid was injected 24 h preceding cell injection, the reduction of retinal detachment was from 85% (control) to 43% (treated). The development of retinal detachment is caused by proliferation of injected fibroblasts. Reduction of this proliferation is probably achieved partially through direct inhibition of mitosis, but more important may be the reduction of the reactive inflammatory process.

Animals↗
PubMed1987

Classification of the stages of proliferative vitreoretinopathy in a refined experimental model in the rabbit eye.

Eighty-four rabbit eyes injected intravitreously with tissue-cultured fibroblasts following gas compression of the vitreous were examined clinically over a period of 1 month. Detailed clinical descriptions of the extent of retinal changes were recorded. Clinical landmarks were determined and arranged into a new classification of this model of proliferative vitreoretinopathy (PVR). The proposed classification will allow easier communication between research groups using this model to study the treatment and prevention of PVR.

Animals↗
PubMed1987

Lattice dystrophy type 1: a report of 8 families.

Eight families with lattice corneal dystrophy are reported. The symptoms and signs are almost identical with the typical lattice corneal dystrophy type 1 in western countries. Lattice corneal dystrophy has been considered to be a rare disease until recently, but it might be a more common disorder. This is the first report of a large series of lattice corneal dystrophy in Japan.

Adolescent↗
PubMed1987

Transvitreal cyanoacrylate retinopexy in the management of complicated retinal detachment.

Failures in vitreous surgery for complex vitreoretinal disorders are frequently due to an inability to keep preexisting or iatrogenic retinal breaks permanently closed. We have used transvitreally delivered cyanoacrylate tissue adhesive to seal retinal breaks in selected patients undergoing vitreous surgery for complicated retinal detachment. With a minimum follow-up period of 6 months, all but one retinal hole have remained closed and complete retinal reattachment posterior to the encircling buckle was achieved in 18 of 25 eyes (72%). In 10 of the 25 eyes (40%) the final visual acuity was 5/200 or better.

Adolescent↗
PubMed1986

Experimental transvitreal cyanoacrylate retinopexy through silicone oil.

We evaluated the use of transvitreal cyanoacrylate retinopexy in the treatment of experimental rhegmatogenous retinal detachment during vitreous surgery in rabbit eyes filled with silicone oil. The view to the fundus was superior to that obtained in our previous model of cyanoacrylate retinopexy in the air-filled eye. Glue delivery was consequently both easier and more precise through silicone oil relative to air. The chorioretinal adhesions produced with cyanoacrylate tissue adhesive were compared with those produced by transscleral retinal cryopexy and were found to be more rapid in onset as well as stronger. An exaggerated tissue response adjacent to the cyanoacrylate site suggested a potential toxic chemical or thermal reaction, or both, to the tissue adhesive, but there was no evidence of any distant ocular effects.

Animals↗
PubMed1986

Temperature-dependent light damage to the retina.

We examined the ability of hypothermic infusion fluid to reduce the risk of light damage to the retina from the intraocular fiberoptic probe during vitreous surgery. Following vitrectomy, we exposed the retina of rabbits to light from an intraocular fiberoptic probe during infusion of fluid at body temperature (39 C) and compared this with exposures during infusion of room temperature fluid (22 C). Retinal irradiance was 0.33 W/cm2. Damage was determined ophthalmoscopically and histologically. Cooling the infusion fluid from body to room temperature extended the damage threshold from approximately 25 to 60 minutes. A 35-minute exposure to body temperature fluid was compared with the same exposure during infusion of room temperature fluid. While retinal and retinal pigment epithelium damage was present after the body temperature exposure, no damage was detected after the room temperature exposure. Vitreoretinal surgeons should avoid warming intraocular infusion fluids to levels above room temperature.

Animals↗
PubMed1986

Experimental transvitreal cyanoacrylate retinopexy.

We used an experimental rabbit model of rhegmatogenous retinal detachment to compare the onset, quality, and duration of chorioretinal adhesions obtained by transvitreal application of N-butyl-2-cyanoacrylate mixed with iophendylate with those obtained by transscleral retinal cryopexy. The chorioretinal adhesions produced by the cyanoacrylate tissue adhesive were immediate in onset, stronger, and long lasting.

Animals↗
PubMed1986

Experimental and clinical observations of the intraocular toxicity of commercial corticosteroid preparations.

We tested the vehicles of six different commercially available depot corticosteroids (Celestone Soluspan, Depo-Medrol, Decadron, Decadron L. A., Aristocort, and Kenalog) for possible toxicity when injected intravitreally. When tested on rabbit eyes, the Celestone Soluspan and the Depo-Medrol vehicles caused remarkable retinal degeneration with preretinal membrane formation or cataracts in their standard concentrations. Three other vehicles (Decadron and Decadron L. A.) caused localized retinal degeneration in twice the standard concentration. Thus, toxic effects can be caused by preservatives or inadequate osmolarity of the vehicles alone. The development of proliferative vitreoretinopathy in some cases of injections of intraocular depot corticosteroid can be explained by retinal necrosis and repair processes caused by these vehicles.

Adrenal Cortex Hormones↗
PubMed1986

A refined experimental model for proliferative vitreoretinopathy.

Animal models of proliferative vitreoretinopathy (PVR) in which the intact vitreous is injected with large numbers of tissue cultured fibroblasts do not accurately represent the disease as it is found in humans. A refined model of PVR is presented, in which the vitreous is compressed and partially detached using intravitreally injected perfluorpropane, followed by injection of 25,000 homologous fibroblasts. Proliferation occurred on the retinal surface, causing retinal detachments with the same frequency as models using greater numbers of cells.

Animals↗
PubMed1986

Primary band-shaped spheroidal degeneration of the cornea: three cases from two consanguineous families.

Three cases of primary band-shaped spheroidal degeneration of the cornea from two consanguineous families are reported. In all cases vision deteriorated slowly, the deterioration beginning in childhood. Photophobia in childhood was also a common symptom, and two patients suffered from intermittent painful sensations. The occupational and environmental histories had no bearing on the cases. Histochemical study of the yellow, oily appearing deposits suggested that this material has a complex composition, with staining characteristics of both protein and acid-fast lipid.

Adult↗
PubMed1986

Specular microscopy of posterior polymorphous endothelial dystrophy.

Corneal endothelial conditions in two children with posterior polymorphous endothelial dystrophy were studied by specular microscopy. The localized vesicular lesions seen by slit lamp formed demarcated blackout areas where two distinct populations of cells were adjacent. Focal areas of highly pleomorphic cells with increased reflective highlights, which may represent epithelial-like cells, were surrounded by enlarged and pleomorphic endothelial cells (background cells). The average background endothelial cell area was three to four times larger than the control area. The composite cells which appeared to coalesce were also observed among the enlarged background cells.

Child↗
PubMed1986

Glio-vascular architecture in the rabbit retina.

Differences between the rabbit and human retinal circulation, and the use of the rabbit eye in a model of experimental retinal neovascularization, necessitates a complete description of the normal vascular structure in the rabbit and its relationship to adjacent tissue, particularly the glia. The gliovascular relationships in the rabbit were studied by scanning and transmission electron microscopy. Utilizing gas compression of the vitreous to clear the wings of overlying vitreous, the authors were able to make detailed observations of retinal surface by scanning electron microscopy. Glial sheaths surrounding a large number of medium size and smaller vessels were observed. The glial sheaths contained cells which were ultrastructurally similar to Müller cells. No isolated glial tufts were observed in avascular areas. Finally, small, smooth-surfaced cells were found adjacent to many vessels. The exact nature and function of these cells remains unknown.

Animals↗