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Biomedical subjects

R Manabe

Publications and source records attributed to R Manabe.

At least 73 records · Page 4Linked to original sources
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↗
PubMed1985

A new punctum plug.

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Equipment and Supplies↗
PubMed1985

Fluid dynamics in eyes with rhegmatogenous retinal detachments.

Inward and outward permeabilities to sodium fluorescein at the blood-retinal barrier were measured by kinetic vitreous fluorophotometry in ten eyes with rhegmatogenous retinal detachments. Fellow eyes were used as controls. Inward permeability of eyes with detachments was significantly larger than that of controls (P less than .005), suggesting damage to the blood-retinal barrier in eyes with detachments. Outward permeability of eyes with detachment and retinal holes was slightly less than that of controls, but the difference was not statistically significant. However, outward permeability of eyes with detachments and with retinal tears was significantly larger than that of controls (P less than .05). This increased outward permeability may be attributed to the increased fluid flow posteriorly through the break across the retinal pigment epithelium.

Adolescent↗
PubMed1985

Co-existence of glucagon- and substance P-like immunoreactivity in the chicken retina.

This immunohistochemical study of chicken retina using flat-mounts shows that pancreatic glucagon- and substance P-like immunoreactive amacrine cells have more heterogeneous subpopulations than was previously understood to be the case. Using double-staining immunohistochemical procedures we demonstrate that a substantial proportion of all subtypes of glucagon-like immunoreactive cells contain substance P-like immunoreactivity and that the ratio of the amacrine cells containing both peptides to total immunoreactive cells varies according to position in the retinal and cell type. These results suggest that retinal cells may have different functions according to position or cell type.

Animals↗
PubMed1985

Actin organization in migrating corneal epithelium of rabbits in situ.

We have found previously that fibronectin enhances the migration of rabbit corneal epithelium both in vitro and in vivo. In this paper we report a change of actin localization in migrating corneal epithelium as determined by immunofluorescent microscopy. Rabbit cornea was cut into small blocks and cultured in TC-199 medium. In the normal cornea, actin was detected as diffuse fluorescence at each epithelial layer. After 8 hr of cultivation epithelial cells had not started to migrate significantly, but actin had accumulated at the cell membrane. After 24 hr, epithelial migration had begun, and actin-specific fluorescence was detected mainly in the basal cell layer at the leading edge. When fibronectin or epidermal growth factor was added to the culture medium, epithelial migration began 8 hr after initiation of culture, and at 24 hr actin-specific fluorescence at the basal side of the migrating epithelial cells appeared stronger than that of a control group cultured in TC-199 unsupplemented medium. At the same time, fibronectin-specific fluorescence was more intense beneath the migrating epithelial cells. It is known that fibronectin has an affinity to collagen, and thus it might coat the cut surface of the stroma. Epithelial cells may attach then to the stroma via coated fibronectin. When a large quantity of exogenous fibronectin is added or when fibronectin is synthesized by the addition of epidermal growth factor, it may further stimulate the organization of intracellular actin from globular form (G-actin) to fibrilar form (F-actin). As a result, the change of intracellular localization and appearance of organized actin molecule might lead to cellular migration.

Actins↗
PubMed1985

Clinical evaluation of fibronectin eyedrops on epithelial disorders after herpetic keratitis.

The clinical efficacy was investigated of fibronectin eyedrops on the nonhealing corneal epithelial defect after herpetic keratitis. Fibronectin eyedrops were prepared from the patient's own blood plasma by an affinity chromatography using gelatin-coupled agarose gel and by gel filtration technique. Twenty eyes with metaherpetic trophic ulcer with persistent epithelial defect that had not responded to conventional therapy were treated by the instillation of fibronectin eyedrops 6 times a day. The mean +/- standard deviation duration of epithelial defect was 61.5 +/- 66.1 days. The epithelial defects healed within 15.6 +/- 12.4 days. These results suggest that fibronectin eyedrops are a possible effective therapeutic approach in nonhealing corneal epithelial defect after herpetic keratitis.

Adolescent↗
PubMed1984

[A comparative study of C19 steroid-induced hypertension and deoxycorticosterone acetate (DOCA)-salt hypertension].

Recently, it has been recognized that 19-hydroxyandrostenedione (19-OH-AD), one of the C19 steroids, acts to amplify the mineralocorticoid activity and to elevate blood pressure. However, there is no detailed report about the pressor mechanism and the effects on several humoral depressor factors, i.e., kallikrein, kinin and prostaglandins etc. Therefore, we studied the differences in the pressor mechanisms and the changes in urinary prostaglandin E (PGE) and kinin excretions among deoxycorticosterone acetate (DOCA)-salt hypertension, 19-OH-AD induced hypertension, and testosterone induced hypertension. In this study, DOCA, 19-OH-AD and testosterone were administered subcutaneously to castrated male rats (Wistar rats, 12 weeks) at a dose of 10 mg/body/week for the first 6 weeks. Then the doses were increased to 30 mg/body/week for the next 5 weeks. These experiments were done in metabolic cages. It was found that 19-OH-AD induced hypertension earlier than DOCA and testosterone. However, 19-OH-AD and testosterone had no effect on the levels of urinary kinin and PGE excretions, while DOCA significantly increased urinary kinin and PGE excretions immediately after the onset of hypertension. Furthermore, DOCA increased the urinary Na/K ratio, while 19-OH-AD and testosterone did not change the ratio. It is suggested that 19-OH-AD might induce the pressor action due to the changes in the vascular reactivity rather than the mineralocorticoid activity.

Androstenedione↗
PubMed1984

Serial alterations in endothelial cell shape and pattern after intraocular surgery.

We serially examined the endothelial cellular pattern and thickness of the central cornea after intracapsular cataract extraction and penetrating keratoplasty. The endothelial cellular pattern was analyzed with a computer-assisted digitizer. We used the frequency of hexagonal cells as the index to describe the degree of hexagonality in the cellular pattern. In the intracapsular cataract extraction group (20 eyes), the frequency of hexagonal cells was 68% preoperatively. During the first four weeks this frequency decreased rapidly to a significantly lower level (52%). The corneal thickness was significantly increased within the first week (0.57 mm) and steadily decreased to preoperative values at four weeks (0.53 mm). During the period from four to 24 weeks, the frequency of hexagonal cells increased gradually to 64%. In the penetrating keratoplasty group (ten eyes), the frequency of hexagonal cells and the thickness at one month were 62% and 0.64 mm respectively. During the next six months the frequency of hexagonal cells decreased significantly to 53%, and the thickness decreased to 0.53 mm. There was a gradual increase in the frequency of hexagonal cells to 62% during the two years after penetrating keratoplasty.

Aged↗
PubMed1984

Quantitative analysis of endothelial mosaic pattern changes in anterior keratoconus.

The corneal endothelia of 21 eyes with anterior keratoconus and 15 eyes of age-matched controls were investigated with a specular microscope. Of the 21 eyes, 15 had definite keratoconus while six apparently normal fellow eyes were designated as latent. The corneal endothelial photographs were subjected to a computerized digitizer analysis of the area and shape of individual cells. The endothelium in keratoconus showed a significant increase in the extent of polymegethism (the coefficient of variation in cell area; 0.36 +/- 0.07) as compared with controls (0.24 +/- 0.03), with the mean cell area staying within normal limits. The relative frequency of hexagonal cells in keratoconus (50.5 +/- 5.7%) was significantly lower than that of controls (70.6 +/- 5.5%). Additionally, an increase of various cell shapes was noted, indicating that there was also a significant increase in cellular pleomorphism. In the latent group, alterations in cellular structure could not be detected by analysis of cell area when compared to controls. However, when these eyes were subjected to cell shape analysis and compared to fellow keratoconic eyes, both eyes showed similar pleomorphic characteristics. These results suggest that in the fellow eye in unilateral keratoconus, even when there are no ocular signs and symptoms, diagnosis can be made early with specular microscopy and computerized cell shape analysis.

Adolescent↗
PubMed1984

[Changes in responses of blood pressure and several hormones to infusions of angiotensin II and angiotensin III in patients with essential hypertension].

In this study, the effects of angiotensin II (A II, Asn-Arg-Val-Tyr-Val-His-Pro-Phe) and angiotensin III (A III, Arg-Val-Tyr-Ile-His-Pro-Phe) on blood pressure (B.P.), pulse rate, several hormones [plasma renin activity (PRA), plasma aldosterone (PA), ACTH, plasma cortisol (PC), urinary catecholamines and urinary aldosterone] and urinary electrolytes were investigated in 9 male patients with essential hypertension [mean age 36.2 +/- 4.1 (S.E.) years]. A II and A III infusions (8 ng/kg/min, 60 min) were started from 0900 h and blood samples were drawn before, at 15, 30, 45, 60 min after the beginning of the infusions, and at 15 min after their cessation. Urinary samples were collected within 2 hrs before and after the infusions, respectively. A II significantly increased B.P.(p less than 0.01) during the infusions, whereas A III did not increase B.P.. PRA significantly decreased after the infusions of A II and A III (p less than 0.05), but the potency of A II was significantly greater than that of A III (p less than 0.01). PA was increased after both infusions, but in response to A III, a peak was observed at 30 min after the infusion and subsequently, the levels decreased gradually. Significant differences between both responses were found at 45 and 60 min (p less than 0.05) after the infusions. ACTH was unchanged during the infusions, but PC was equipotentially suppressed during the infusions, with the suppression of A II being similar to that of A III. In the responses of urinary catecholamines, noradrenaline and dopamine were equipotentially decreased after the infusions (p less than 0.05). The results of the present study clearly indicate that several differences exist between the biological activities of A II and those of A III. Further systematic experimental studies are needed to resolve the details.

Adrenocorticotropic Hormone↗
PubMed1984

Fibronectin enhancement of corneal epithelial wound healing of rabbits in vivo.

The effect of topical administration of fibronectin on corneal reepithelialization in vivo was investigated in rabbits. Rabbit plasma fibronectin was purified by affinity chromatography using gelatin-coupled agarose gel (Sepharose 4B). The concentration of purified fibronectin was adjusted to 0.75 mg/mL. Corneal epithelial cells were removed by iodine vapor in 13 rabbits (26 eyes), and the size of the epithelial defect was calculated from the printed photographs in each eye. Fibronectin or phosphate-buffered saline eye drops were instilled. Healing rate was calculated by linear regression. The mean epithelial healing rate in fibronectin-treated eyes was 1.62 +/- 0.33 sq mm/hr, whereas in the control eyes it was 1.30 +/- 0.35 sq mm/hr. This study shows that fibronectin facilitates corneal epithelial wound healing in vivo.

Administration, Topical↗
PubMed1984

Ontogeny of substance P-containing structures in the ocular tissue of the rat: an immunohistochemical analysis.

The ontogeny of the substance P-like immunoreactivity (SPI) containing system in the ocular tissue of the rat was examined by means of the indirect immunofluorescence method. SPI-containing amacrine cells first appeared at postnatal day 4 and displaced SPI-containing amacrine cells at postnatal day 5. After this time, they developed markedly reaching their maximum content and distribution at postnatal day 14. On the other hand, SPI-containing cells in the trigeminal ganglion were first seen at gestational day 17 and reached their maximum content at birth. SPI-containing fibers in the cornea and uvea were first observed at gestational days 17-19. The SPI-containing fibers in the iris reached their maximum content at birth, while those in the cornea, choroid and ciliary body were fully developed at postnatal day 3. In the adult rats, numerous SPI structures were still seen in the ocular tissue, retina, cornea and uvea. These findings suggest that SPI might play some role in the developing ocular tissue in addition to its neurotransmitter or neuromodulator role in the adult, because SPI structures appear in the retina before establishment of synaptogenesis and in the cornea and uvea during the fetal stage.

Animals↗
PubMed1984

Subretinal neovascularisation in eyes with localised inferior posterior staphylomas.

We report seven cases of subretinal neovascularisation with inferior posterior staphyloma. The upper border of the shallow staphyloma, detected by B-mode echography, invaded the macular area, and there was a neovascular net at the edge of the staphyloma. Three of the cases showed chorioretinal atrophy at the upper edge of the staphyloma in the same location as the neovascular net. Our cases were identical to those of subretinal neovascularisation in high myopic eyes in which the rupture of Bruch's membrane was related to the deformity of the scleral shell. As our cases included not-high-myopic eyes, the results suggest that the identical mechanism might be involved in the occurrence of neovascular maculopathy in the pathological high myopic eye and in the not-high-myopic eye with posterior staphyloma. Localised inferior posterior staphyloma may be an important cause of 'idiopathic' subretinal neovascularisation.

Adult↗