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Biomedical subjects

R Manabe

Publications and source records attributed to R Manabe.

At least 37 records · Page 2Linked to original sources
PubMed1990

[Herpes simplex virus latency in the cornea].

We tried to identify herpes simplex virus type 1 (HSV-1) latency in the cornea obtained at the time of penetrating keratoplasty from patients with herpetic stromal keratitis in the non-active (subsided) stage. The subject consisted of 8 patients (3 males and 5 females; average age 42.3 years) who were diagnosed as having herpetic stromal keratitis and underwent penetrating keratoplasty during a period without active lesions (subsided stage) between August, 1984 and July, 1988. No infective virus was detected in the centrifugation supernatant following each corneal homogenization. Latent virus was detected from the culture supernatant of sections of the corneas in 4 of the 8 patients. Although the ganglion trigger theory of Hill et al. has been conventionally supported as the mechanism(s) of herpetic keratitis recurrence, our results suggest that HSV-1 proliferation from latency in the cornea (peripheral tissue) might stimulate the ganglion (ganglion and skin trigger theory). The present study is the first to demonstrate HSV-1 latency in the cornea.

Adult↗
PubMed1990

The mechanism of accelerated corneal epithelial healing by human epidermal growth factor.

The effect of biosynthetic human epidermal growth factor (hEGF) was investigated on a 10-mm diameter corneal epithelial defect model in rabbits. Topical application of over 10 micrograms/ml of hEGF five times a day significantly enhanced the epithelial healing rate, in a dose-dependent manner. The maximum healing rate was observed in eyes treated with 20 micrograms/ml of hEGF (1.59 +/- 0.26 mm2/h), whereas application of less than 5 micrograms/ml of hEGF did not increase the rate of epithelial regeneration compared statistically with control vehicles (1.03 +/- 0.24 mm2/h). S-phase analysis indicated that hEGF treatment induced a high rate of epithelial replication, particularly near the limbal region, during 12 to approximately 24 hours after wounding, followed by massive cell replication from 1 mm behind the leading edge through the limbus during 24-48 hours. The change in number and distribution of S-phase cells thereafter did not essentially differ between hEGF-treated and control groups. In concordance with the S-phase analysis, there was a statistically significant increase in the DNA content in regenerating epithelium at 48 and 72 hours in the hEGF-treated group. These findings indicate that hEGF-induced acceleration of large corneal epithelial wound healing is associated with about twofold cell replication in the regenerating epithelium during 24 to approximately 48 hours after wounding. It is concluded that cell proliferation induced by hEGF, particularly that in limbal and peripheral corneal epithelial cells, may play an important role in accelerating epithelial healing.

Administration, Topical↗
PubMed1989

Coexistence of enkephalin and somatostatin in the chicken retina.

A double immunostaining method was used in the present study to demonstrate that enkephalin (ENK) and somatostatin (SOM) coexist within single amacrine cells of the chicken retina. The ratio of double-labeled cells to either ENK- or SOM-bearing cells was more than 90%, indicating that retinal ENK and SOM are most likely to be found together in the same amacrine cell. This rate of colocalization is the highest yet observed among any neurotransmitters and modulators that coexist.

Animals↗
PubMed1989

The effect of hard contact lens wear on the keratoconic corneal endothelium after penetrating keratoplasty.

Using wide-field specular microscopy, we evaluated the morphologic features of the corneal endothelium in 14 eyes of 14 patients with keratoconus who had worn a polymethylmethacrylate hard contact lens for at least four years (mean, 71 months) after penetrating keratoplasty. Comparisons were made with 14 non-lens-wearing eyes of 14 patients with keratoconus matched for age, length of postoperative period, and other variables. Examination of the endothelium of the contact lens wearers showed a significantly higher coefficient of variation in cell size (polymegethism) and a marked decrease in the percentage of hexagonal cells (pleomorphism), with a significant decrease in cell density (P less than .05). The cause of these morphologic abnormalities remains unclear but may be related to lens-induced hypoxic stress to the corneal endothelium causing ongoing cell loss.

Cell Count↗
PubMed1989

A case of neurofibroma located in the retroperitoneum involving the uncinate process of the pancreas.

A case of solitary neurofibroma in the retroperitoneum involving the uncinate process of the pancreas, which has been reported in only one case in Japan and less than 20 cases in the world literature, is described. A 57-year-old male complained of back pain and microhematuria. Plain and enhanced abdominal computed tomography (CT) indicated an 8 x 6 cm hypovascular tumor located in the uncinate process. We initially assumed it to be a cancer of the pancreas. His physical examination and blood chemistry result were normal. Various diagnostic imaging methods however, disclosed a rare type of tumor. The tumor was resected by pancreaticoduodenectomy and histological examination revealed it to be neurofibroma.

Humans↗
PubMed1989

Co-localization of adrenergic receptors and vitamin-D-dependent calcium-binding protein (calbindin) in the dopaminergic amacrine cells of the rat retina.

Using antisera against tyrosine hydroxylase (TH) and purified beta 2-adrenergic receptors (beta 2-AdR), we found that TH- and AdR-like immunoreactivities coexisted in large amacrine cells. These findings indicated an association between dopamine-containing amacrine cells and adrenergic amacrine cells. The present study also showed that amacrine cells with TH-like immunoreactivity have vitamin-D-dependent calcium-binding protein (calbindin, 27,000 kDa)-like immunoreactivity as well, suggesting that calbindin plays an important postsynaptic role in dopaminergic amacrine cells.

Animals↗
PubMed1989

Intraocular penetration of CT-112, an aldose reductase inhibitor, following topical instillation.

Intraocular penetration of 5-(3-ethoxy-4-pentyloxyphenyl)thiazolidine-2,4-dione (CT-112), an aldose reductase inhibitor, was investigated in rabbits following topical instillation. The concentration of CT-112 in corneal epithelium, stroma, endothelium, lens, and aqueous humor, was sequentially determined by high-performance liquid chromatography. CT-112 peaked in the corneal epithelium, stroma, endothelium and aqueous humor in 30 minutes following instillation, then gradually diminished time-dependently over a period of 24 hours. CT-112 remained detectable in the lens up to 24 hours, with a peak concentration at 2 hours after instillation.

Administration, Topical↗
PubMed1989

A case of simultaneous bilateral herpetic epithelial keratitis.

The patient, a 56-year-old man, presented with dendritic keratitis in the right eye and geographic keratitis in the left, with decreased corneal sensation in both eyes. The virus isolated from both eyes was identified as herpes simplex virus (HSV-1) by the indirect immunofluorescent method using anti-HSV-1 monoclonal antibody. Antibody tests of paired sera suggested that the epithelial lesions were not primary but recurrent. No significant difference was observed in DNA cleavage patterns between the virus isolates obtained bilaterally.

Cell Division↗
PubMed1989

Comparative efficacy of three antiviral drugs in mice herpetic keratitis.

The antiherpetic effects of 9-(1,3-dihydroxy-2-propoxymethyl)guanine (DHPG) in vitro and in vivo were investigated in comparison with those of acyclovir (ACV) and 5-iodo-2'-deoxyuridine (IDU). ACV was found to be consistently superior to the other two agents in antiviral activity against all ocular isolates in vitro. In vivo tests in mice, in contrast, showed DHPG in ointment form to be more effective than ACV in treating herpetic keratitis. It was noted that even 0.03% DHPG ointment was as efficacious as 0.3% ACV ointment. Other studies using the same keratitis model also demonstrated that DHPG eyedrop solution is far more effective than IDU eyedrop solution. These results indicate that DHPG can be a useful antiviral agent in the treatment of herpetic keratitis.

Acyclovir↗
PubMed1989

[Penetrating keratoplasty and cataract surgery].

Of 46 eyes undergoing simultaneous penetrating keratoplasty and cataract extraction, 25 grafts (54%) remained clear with an average follow-up of 37 months. This low success rate can be party explained by the fact that more than 50% of our patients had unfavourable ocular conditions preoperatively. In case of simultaneous procedures, methods of cataract extraction (ICCE or ECCE) did not have any significant affect on the rate of clear grafts. In eyes with favourable ocular conditions preoperatively, the rates of clear grafts were similar (approximately 75%) in cases of simultaneous operation (21 eyes) and separate operation (8 eyes).

Adult↗
PubMed1989

Differential regulation of fibronectin synthesis in three different types of corneal cells.

The production of fibronectin (FN) and its response to serum or epidermal growth factor (EGF) were investigated in three different types of rabbit corneal cells cultured in vitro. The corneal epithelial cells, stromal fibroblasts (keratocytes) and endothelial cells were separately cultured in different media: basic medium containing minimal serum (0.5%), basic medium with supplementary serum at a final concentration of 10% and basic medium with 100 ng/ml EGF, respectively. FN production by each type of cell was examined either by the immunofluorescent staining method or by the metabolic labeling method followed by immunoprecipitation of FN in the culture medium. Each type of corneal cell produced and secreted FN. FN secretion into the culture medium by keratocytes and by endothelial cells was enhanced by the addition of EGF. However, FN secretion by epithelial cells was lowered by the additional serum or EGF. Furthermore, when the epithelial cells were cultured in the basic medium, DNA synthesis was low but FN secretion was high. These results suggest that the control mechanism of FN production differs between epithelial cells and keratocytes or endothelial cells.

Animals↗
PubMed1989

Presence of epidermal growth factor in human tears.

Epidermal growth factor (EGF) is a polypeptide that stimulates the growth of various tissues, including the cornea. The presence of EGF in tears from normal volunteers and in aqueous humor from cataract patients was investigated via human EGF (hEGF)-specific radioimmunoassay. Immunoreactive hEGF was found to be present at similar concentrations in both reflex (ranging from 0.7 to 8.1 ng/ml) and non-reflex tears (ranging from 1.9 to 9.7 ng/ml), but was undetectable in aqueous humor. Immunoreactive EGF in human tears was indistinguishable immunologically, biologically and biochemically from urine EGF and standard hEGF.

Adult↗
PubMed1988

Vitamin A eyedrops for superior limbic keratoconjunctivitis.

We treated 12 patients with superior limbic keratoconjunctivitis with topical vitamin A (retinol palmitate) eyedrops. After a follow-up period of at least three months, this therapy was found to be effective, to a varying extent, in ten patients (83%). Superior limbic keratoconjunctivitis lesions did not recur in these patients as long as topical application was continued.

Adult↗
PubMed1988

Aldose reductase inhibitor (CT-112) eyedrops for diabetic corneal epitheliopathy.

We treated two diabetic patients with corneal epithelial disorder that resisted conventional medical therapy with topical CT-112 (5-[3-ethoxy-4-pentyloxyphenyl]-2,4-thiazolidinedione), a newly synthesized aldose reductase inhibitor. One patient had developed recurrent corneal erosion after vitrectomy and the other had spontaneously developed superficial punctate keratopathy. The corneal lesion in each patient responded to topical CT-112 in two to four weeks and was almost cleared within two months. A similar corneal lesion recurred in both patients soon after CT-112 was discontinued, but it disappeared again when the drug was resumed.

Aged↗
PubMed1988

Histamine H1-receptor in the retina: species differences.

Histamine H1-receptors in membranes of the various mammalian retinas were studied by [3H]mepyramine binding assay. Specific [3H]mepyramine bindings to bovine, pig, dog and human retinas were observed with the dissociation constants (KD), 3.8 +/- 1.2 nM, 1.8 +/- 0.6 nM, 2.6 +/- 0.6 nM and 3.0 +/- 0.9 nM, respectively, which were similar to those found in brains. But there was no detectable specific binding in the guinea-pig and rabbit retinas. The number of binding sites (Bmax) ranged from negligible value to 290.7 +/- 51.7 fmole/mg protein(human retina). Some H1-antagonists acted as potent agents in competing with [3H]mepyramine binding to bovine and pig retinas. These results indicated that histamine H1-receptors exist in some mammalian retina and have similar characteristics to those in brain membranes, but they distributes in the wide difference of the binding capacities among the species, while in brain variations were smaller.

Animals↗
PubMed1988

The corneal endothelium following autokeratoplasty. A case report.

An autokeratoplasty was performed on the left eye of a 64-year-old female, with the graft transferred from the contralateral, blind eye. The endothelial morphology and thickness of the central cornea were studied pre-operatively and yearly for 6 years after surgery. The endothelial cell density decreased rapidly during the first 2 years post-operatively (55.5%), after which cell loss occurred at a considerably slower rate (about 2% of the pre-operative cell density per year). During the observation period, the coefficient of variation in cell size stayed relatively constant (approximately 0.3). When the corneal thickness returned to normal 2 months after surgery, the endothelium showed a significant decrease in the percentage of hexagonal cells (15.0%). Between 2 months and 2 years post-operatively, the percentage of hexagonal cells gradually returned to normal. These endothelial changes noted are remarkably similar to those previously seen in homografts, suggesting that cell damage due to immunologic reactions may not be a major factor in long-term endothelial changes after homografting.

Cornea↗
PubMed1988

Corneal endothelial changes associated with herpetic stromal keratitis.

Wide-field specular microscopy was performed on both eyes of 33 patients with unilateral herpetic stromal keratitis. Endothelial changes were quantitated by computerized morphometric analysis of individual cells. In the 16 patients with disciform keratitis, the corneal endothelium of the affected eyes showed no difference in cell density but demonstrated significant increases of variation in cell size (polymegathism) and shape (pleomorphism) when compared to the cells in the fellow unaffected eyes. The eyes with keratouveitis (17 patients), however, had marked polymegathism and pleomorphism of the endothelium and a distinctly lower endothelial cell density (mean, 19%) than the healthy fellow eyes.

Adolescent↗