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Biomedical subjects

R Manabe

Publications and source records attributed to R Manabe.

At least 55 records · Page 3Linked to original sources
PubMed1987

Herpetic keratitis therapy to reduce recurrence.

Since the herpes simplex virus locates latently in the ganglia and is reactivated by certain triggers, the important problem in treatment is to prevent or reduce recurrence. The present study investigates the role of mechanical debridement in lessening the recurrence of dendritic keratitis in patients with herpetic epithelial keratitis. Group A was treated with mechanical debridement plus IDU, Group B with IDU alone. Also studied was the effect of steroid subconjunctival injection on herpetic recurrence in patients with herpetic stromal keratitis: Group C was treated with intravenous infusion of pepsin-treated gamma-globulin (PTGG) and steroid subconjunctival injection, Group D with steroid subconjunctival injection alone and Group E with intravenous infusion of PTGG alone. The recurrence rates of dendritic keratitis were 19% in Group A and 40% in Group B (average follow-up periods: 24 and 25 months). The recurrence rates of stromal keratitis were 61% in Group C, 64% in Group D, and 36% in Group E (average follow-up periods: 20, 19 and 15 months). The difference between Groups D and E was statistically significant (chi 2 test, P less than 0.05). The recurrence rates of dendritic keratitis were 18% in Group C, 21% in Group D and 7% in Group E. In conclusion, mechanical debridement tended to reduce the recurrence of herpetic epithelial keratitis and steroid subconjunctival injection to increase the recurrence of epithelial or stromal keratitis.

Administration, Topical↗
PubMed1987

The effects of aldose reductase inhibitor on the corneal endothelial morphology in diabetic rats.

Diabetic rats were produced by intravenous injection of streptozotocin. Of these, eleven rats were treated with topical instillation of 0.5% aldose reductase inhibitor (ARI), while ten received vehicle alone. The corneal endothelium of these diabetic rats was examined by specular microscopy and compared to age-matched nondiabetic rats (ten rats). Computerized morphometric analysis of individual cells demonstrated that the endothelium of the untreated diabetic rats had marked polymegathism (increased coefficient of variation in cell area) and pleomorphism (decreased percentage of hexagonal cells), as previously observed in diabetic patients. Similar endothelial changes were also noted in the ARI-treated diabetic rats, but to a significantly lesser extent. These results suggest that topically applied ARI can be effective in reducing morphologic changes of the diabetic endothelium, and that activation of the sorbitol pathway may be implicated in the etiology of such endothelial changes.

Aldehyde Reductase↗
PubMed1987

Induction of cytochrome P-450 in the rabbit eye by phenobarbital, as detected immunohistochemically.

The present study was aimed to demonstrate that cytochrome P-450 was induced by drug administration in particular tissues in the eye. Phenobarbital was used as an inducer. We showed immunohistochemically that cytochrome P-450 was induced in the cornea, conjunctiva and ciliary epithelium of rabbits after four days of intraperitoneal administration of phenobarbital at a dose of 80 mg per kg per day. We did not detect significant immunofluorescence in other ocular tissues. Prolonged administration caused degeneration of the ciliary epithelium, but not pathological change was seen in other ocular tissues. In this case, immunofluorescence was not detected in the ciliary epithelium but in the cornea, conjunctiva and lens.

Animals↗
PubMed1987

Interferon enhances the natural killer cell activity of the retinoblastoma patients to autologous retinoblastoma cells.

The cytotoxic activities of the peripheral lymphocytes prepared from two retinoblastoma patients to freshly isolated autologous tumor cells were measured using 51Cr-release assay. The retinoblastoma cells of the two patients resisted lysis by unstimulated effectors, whereas interferon(IFN)-stimulated effector cells gave a significantly higher cytotoxicity. This result implies that IFN therapy may be potent in treating high-risk retinoblastoma patients.

Cytotoxicity, Immunologic↗
PubMed1987

Dome formation in cell cultures of chick embryo retinal pigment epithelium and effects of ouabain and 2,4-dinitrophenol thereon.

Cells from chick embryo retinal pigment epithelium were cultured on glass slips. The primary culture cells formed confluent cell layers which were studded with a number of domes. The domes had usually appeared by the fourth day of culture and were susceptible to 3 X 10(-6) M ouabain and 10(-4) M 2,4-dinitrophenol, indicating that fluid was transepithelially transported from the apical to the basal side by means of an energy-requiring and ouabain-sensitive mechanism. Other than domes, small blisters appeared after 4-10 days of culture. They were also susceptible to the metabolic inhibitors.

2,4-Dinitrophenol↗
PubMed1987

Indomethacin and the epinephrine-induced breakdown of the blood-ocular barrier in rabbits.

Using aqueous and vitreous fluorophotometry, the authors examined the blood-aqueous and blood-retinal barrier functions in three groups of pigmented rabbits. Epinephrine (1.25%) was applied topically five times daily and indomethacin (0.5% sesame oil suspension) was applied topically three times daily to one eye of each of the animals in Group 1; under the same regimen, epinephrine and indomethacin placebo were administered to one eye of each of the animals in Group 2 and epinephrine placebo and indomethacin placebo were administered to one eye of each of the animals in Group 3. Fluorophotometry was done 1, 2, and 3 months after drug administration. The results showed that epinephrine induced disruption of the blood-aqueous barrier 2 and 3 months after drug administration, and that the magnitude of this disruption increased with time. Epinephrine also induced disruption of the blood-retinal barrier 3 months after drug administration. Indomethacin significantly prevented disruption of the blood-aqueous barrier at 2 and 3 months and significantly prevented disruption of the blood-retinal barrier at 3 months. The magnitudes of the barrier disruptions in eyes treated with both epinephrine and indomethacin were slightly higher than, or the same as, those of the control eyes. The results strongly indicated that the epinephrine-induced disruption of the blood-ocular barrier was partially caused by prostaglandins and other cyclo-oxygenase products whose biosynthesis was initiated by epinephrine.

Animals↗
PubMed1986

Effects of intravenous administration of a calcium antagonist on prostaglandins and thromboxane in plasma and urine in humans.

The effects of a calcium antagonist [Nicardipine hydrochloride (NH)] on the prostaglandin [prostaglandin E2 (PGE2), and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha)] and thromboxane B2 levels in the blood and urine were examined in 6 patients with essential hypertension following intravenous infusion of NH for 120 minutes. At the same time, the plasma renin activity (PRA), plasma aldosterone concentration (PAC), and plasma and urinary electrolyte levels were also determined. During NH administration, the blood pressure was significantly decreased (p less than 0.05) with an increased pulse rate (p less than 0.05). PRA was significantly increased after NH loading (p less than 0.05) but PAC showed no change. The plasma PGE2 and 6-keto-PGF1 alpha levels tended to increase slightly, while the blood thromboxane B2 level showed a decreasing tendency. The 6-keto-PGF1 alpha to thromboxane B2 ratio was significantly increased after NH loading as compared to the preloading ratio (p less than 0.05), and then returned to the preloading value at about 30 minutes after discontinuation of NH loading. The urinary excretions of PGE2, 6-keto-PGF1 alpha and thromboxane B2, PGE2 and 6-keto-PGF1 alpha tended to decrease after NH loading. In particular, the decrease in PGE2 was statistically significant (p less than 0.05). No change occurred in the urinary excretion of thromboxane B2. The above findings indicate that NH increased the plasma 6-keto-PGF1 alpha to thromboxane B2 ratio but decreased the urinary excretion of prostaglandins. In addition, the possible involvement of an enhanced 6-keto-PGF1 alpha/thromboxane B2 ratio in part of the hypotensive mechanism of NH is suggested.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

Photokeratoscopy in fitting contact lens after penetrating keratoplasty.

The formula based on keratometric readings which is generally used is unsatisfactory for fitting contact lenses after penetrating keratoplasty, possibly owing to lack of information on the peripheral corneal toricity. In these studies a photokeratoscope was used to examine the entire graft topography. In all cases the corneal configuration became more normal after suture removal, but a considerable toricity still remained, especially near the graft-host junction. One month after removal of sutures spherical hard contact lenses (polymethylmethacrylate, PMMA) were fitted to 30 patients in accordance with data obtained by computerised analysis of the photokeratograms. Of the 30 patients (contact lens wearers) 27 (90%) obtained a stable vision of better than 20/30 for eight hours daily, and 24 (80%) achieved a stable vision of 20/20 for their full waking hours. After one year the contact lens wearers showed a significant decrease in the extent of astigmatism when compared with the non-contact-lens wearers (10 patients). These results suggest that the photokeratoscope can be more useful than ordinary keratometers in fitting contact lenses after keratoplasty, and that hard contact lenses have moulding effects on the graft topography.

Adolescent↗
PubMed1986

Aspects of electrolyte transport across isolated dog retinal pigment epithelium.

Transport of Na and Cl across the isolated dog retinal pigment epithelium (RPE) choroid was investigated. Under the short-circuit condition, a net Na flux was observed from choroid to retina and a net Cl flux was determined in the opposite direction. The current created by the net flux of these two ions was larger than the short-circuit current (SCC). Addition of 10(-5) M ouabain to the apical side inhibited net fluxes of both Na and Cl, whereas it reduced the SCC 84%. Addition of 10(-4) M furosemide to the apical side inhibited net Cl flux but had no effect on the net Na transport. The 10(-4) M furosemide reduced the SCC 38%. These drugs had no effect when applied to the basal side. Thus the transport of both Na and Cl depends on the Na-K-ATPase in the apical membrane of the dog RPE. A furosemide-sensitive neutral carrier at the apical membrane is suggested for the transport of Cl. Replacement of HCO3 with SO4 in the bathing solution caused an increase in the SCC, indicating the choroid-to-retina movement of HCO3 across the short-circuited dog RPE choroid.

Animals↗
PubMed1986

Cytochrome P-450 and related components of the microsomal electron transport system in the bovine ciliary body.

Microsomes were prepared from bovine ciliary bodies. The contents of cytochrome P-450 and related components of the microsomal electron transport system were determined. The cytochrome P-450 content was 32 pmoles/mg protein, which was about 4% that in rat liver. The cytochrome b5 content was 59 pmoles/mg protein. The NADH-cytochrome c reductase and NADPH-cytochrome c reductase activities were 268 and 18 nmoles/min/mg protein, respectively. The ethoxyresorufin deethylase activity was 2.1 pmoles product formed/min/mg protein.

Animals↗
PubMed1986

A newly established cell line of rabbit lens epithelium.

Rabbit lens epithelial cells have been cultured continuously for more than 24 months (200 generations) in monolayers. Their morphology resembled cobblestones when confluent and was spindle-shaped during growth. The doubling time was 40 hours. The cells were capable of colony formation and their plating efficiency was about 6%. They had immunoreactivity to antiserum to the crystalline-rich supernatant of rabbit lens homogenate. Therefore, it was concluded that they were a permanent cell line and they were named TOTL-86 cells.

Animals↗
PubMed1986

Corneal endothelial cell damage associated with intraocular gas tamponade during pars plana vitrectomy.

A prospective study was conducted of corneal endothelial damage associated with intraocular gas tamponade during pars plana vitrectomy performed in 44 patients. In addition to vitrectomy or combined vitrectomy-lensectomy, 25 patients (the gas-treated group) underwent intraocular gas tamponade, which was not performed in 19 patients (the control group). The central corneal endothelium was examined with a specular microscope preoperatively and 3 months postoperatively. Endothelial changes were quantitated by computerized morphometric analysis of individual cells. A total of 20 eyes were phakic after vitrectomy, 13 eyes in the gas-treated group and 7 eyes in the control group. The mean endothelial cell loss for the gas-treated group (1.9%) did not differ significantly from that for the control group (1.8%). Twenty-four eyes were aphakic after vitrectomy, 12 eyes in the gas-treated group and 12 eyes in the control group. The gas-treated group had a significantly greater cell loss (28.3%) than those in the control group (16.3%).

Air↗