Search PubMed⌕ Search

Biomedical subjects

Y Tano

Publications and source records attributed to Y Tano.

At least 73 records · Page 4Linked to original sources
PubMed2000

The effects of binocular suture and dark rearing on the induction of c-fos protein in the rat visual cortex during and after the critical period.

It has been demonstrated in kittens that binocular lid suture has more deleterious and irreversible effects on plasticity of the developing visual system than rearing in complete darkness. The present study using immunocytochemistry focuses on the effects of the two types of visual deprivation on the inducibility of c-fos protein in visual cortical neurons of rats. Rats were subjected to binocular suture or dark rearing for 1 week during (postnatal days 14-21; P14-P21) and after (P50-P57) the critical period for activity-dependent modifiability of cortical ocular dominance. In rats of both age groups reared in the normal light-dark condition, only a small number of Fos-immunoreactive neurons was obtained in the visual cortex. By contrast, in dark-reared pups and adult rats, numerous c-fos neurons were detected in the layers II-IV and VI of the visual cortex following a brief light exposure (1 h). In rats of both ages subjected to binocular suture, Fos neurons were detected in the same layers as in the dark-reared rats, but significantly less in number. We speculate that the reduced plasticity of the visual cortex in the rats subjected to binocular suture may be due partly to the repressed AP-1 activity in visual cortical neurons. No significant difference was detected in c-fos expression in the visual cortex between visually manipulated pups and adult rats.

Aging↗
PubMed2000

Minimizing radial-keratotomy-induced diurnal variation in vision using contact lenses.

A 41-year-old man with 16 radial keratotomy (RK) incisions in each eye reported a paradoxical diurnal variation in vision in both eyes with low Dk/L soft contact lenses. After rk, the patient experienced the conventional diurnal change a morning-to-evening mean (right and left eyes) myopic change of -1.80 diopters (D). However, while wearing low Dk/L contact lenses, a paradoxical morning-to-evening mean hyperopic change of 2.30 D was found. The diurnal variation was minimized (0.50 D) by wearing high Dk/L contact lenses. These results suggest that contact lenses can be used to treat diurnal variation in manifest refraction after RK by inducing appropriate stress.

Adult↗
PubMed2000

The spectrum of beta ig-h3 gene mutations in Japanese patients with corneal dystrophy.

PURPOSE: This study was undertaken to identify beta ig-h3 gene mutations in Japanese patients with granular corneal dystrophy (GCD), Avellino corneal dystrophy (ACD), lattice corneal dystrophy (LCD), and Reis-Bücklers' corneal dystrophy (RBCD). R124H, R124C, R555W, and R555Q mutations have been reported in Europe to cause ACD, LCD type I, GCD, and RBCD, respectively. METHODS: In total, 91 Japanese patients who had been clinically diagnosed with GCD, LCD, or RBCD were investigated to determine whether they had mutations in the beta ig-h3 gene. Genomic DNA was amplified using the polymerase chain reaction and analyzed using single-strand conformation polymorphism techniques. Mutations were identified using the direct sequencing method. RESULTS: In 68 unrelated patients who had been diagnosed with GCD, 62 patients (91%) were found to have the R124H mutation, which has been reported to cause ACD, whereas only six patients (9%) had the R555W mutation. In LCD patients, 10 patients with type I disease had the R124C mutation, and 10 patients with type IIIA disease had a P501T mutation. One patient with atypical LCD had an L527R mutation. In two patients with RBCD, one had an R555Q mutation and the other patient with geographic opacities was found to have an R124L mutation. CONCLUSIONS: Depending on the specific mutation in the beta ig-h3 gene, the phenotypes of corneal dystrophy may differ. Our results indicate that assay of mutations in the beta ig-h3 gene is required to establish a correct diagnosis.

Corneal Dystrophies, Hereditary↗
PubMed2000

Corneal guttata associated with the corneal dystrophy resulting from a betaig-h3 R124H mutation.

AIMS: To investigate the frequency of corneal guttata in patients with a corneal dystrophy resulting from an Arg124His (R124H) mutation of betaig-h3 gene. METHODS: Slit lamp examination was performed on 30 eyes with corneal dystrophy from a genetically confirmed betaig-h3 R124H mutation and on 50 age matched control eyes. The stage of the corneal dystrophy was classified as stage 0, I, or II and the degree of guttata was classified as none, mild, or severe. Specular microscopic examinations were performed to evaluate the morphology of the corneal endothelium. RESULTS: Slit lamp examination disclosed the presence of corneal guttata in 21 eyes (70%) of the 30 eyes with the corneal dystrophy, but in only one (2%) of the 50 eyes in the age matched control group (p<0.001, chi(2) with Yates's correction). Of the 12 eyes with stage I betaig-h3 R124H corneal dystrophy, seven had no corneal guttata and five had a mild degree of guttata. Of the 18 eyes with stage II, the degree of guttata was none in two, mild in nine, and severe in seven. The degree of corneal guttata was significantly related to the stage of the corneal dystrophy (p<0.0001, Kruskul-Wallis test ANOVA on ranks). There was no significant differences between eyes with betaig-h3 R124H corneal dystrophy and normal eyes in cell density, coefficient of variation, and cell hexagonality of corneal endothelium. CONCLUSION: Corneal guttata are one of the characteristics of the corneal dystrophy resulting from betaig-h3 R124H mutation.

Aged↗
PubMed2000

Intraoperative adjunctive agents in vitrectomy: serum, cytokines, and glue.

The surgical goal in the treatment of retinal breaks is to seal the edges of the break, and traditionally, photocoagulation and cryocoagulation have been used to accomplish this. However, it is sometimes difficult in complicated retinal detachments to maintain the seal against tractional forces. Adhesion is achieved through a process of cell necrosis, inflammation and subsequent fibrovascular proliferation. This strategy, however, may not be appropriate in vision-sensitive areas such as macular holes. To improve the success rate of macular hole surgery, a number of authors have advocated the use of biological modifiers, such as transforming growth factor beta, human autologous serum, tissue glue, or platelet concentrates. These materials may enhance the adhesion of the detached retina and therefore lead to a better anatomical and functional success. We have reviewed the advances of intraoperative application of synthetic or biological adhesives. However, through the improvement of surgical techniques and surgeons' skills in recent years, the anatomical success rate of macular hole surgery has increased in most institutions without adjunctive additives. Thus, many surgeons believe that adjunctive additives may not be necessary for most idiopathic macular holes.

Animals↗
PubMed2000

Fixation patterns of idiopathic macular holes after vitreous surgery.

BACKGROUND: Evaluation of idiopathic macular holes with the scanning laser ophthalmoscope (SLO) has shown fixation to be located at or near the margin of the hole and above the horizontal meridian in most cases. However, changes between preoperative and postoperative fixation have not been well studied. METHOD: We used SLO microperimetry to determine scotomas and fixation points in 13 patients with idiopathic macular holes before and after vitreous surgery. The distance between preoperative and postoperative fixation points and the direction of movement were measured. RESULTS: Preoperatively, fixation was found to be at or near the margin of the macular hole in all eyes and was located above the horizontal meridian in most (84.6%) eyes. Postoperatively, there was a shift in the position of the fixation points. The distance between preoperative and postoperative fixation correlated with the degree of visual improvement (P = 0.032), but the direction of movement was variable. CONCLUSION: A shift in the position of fixation occurs after macular hole surgery, and the amount of shift correlates with visual improvement. From this observation, we define the term functional macular hole closure, characterized by centripetal movement of the neurosensory retina and improvement in vision, and the broader term anatomic macular hole closure, in which apparent hole closure may result from gliosis in the absence of movement of the neurosensory retina, not associated with visual improvement.

Adult↗
PubMed2000

Retinal fascin: functional nature, subcellular distribution, and chromosomal localization.

PURPOSE: To investigate the functional properties, subcellular localization, and chromosomal location of retinal fascin. METHODS: Recombinant retinal fascin protein was prepared by using a baculovirus-insect expression system. Actin-binding and -bundling assays were performed with chick actin purified from skeletal muscle. Western blot analysis and immunohistochemistry were performed with a polyclonal antibody raised against bovine retinal fascin. A human retinal cDNA library was screened with an expressed sequence tag cDNA fragment. Chromosomal location was determined with fluorescent in situ hybridization. RESULTS: The actin-binding and actin-bundling activities of retinal fascin were demonstrated by high- and low-speed centrifugation assays. Formation of filamentous (F)-actin bundles by retinal fascin in vitro was also morphologically confirmed by fluorescence microscopy and electron microscopy. Immunohistochemical analysis revealed that retinal fascin protein was localized specifically in the outer and inner segments of the photoreceptor cells in the retina. Two splicing variants of human retinal fascin cDNA were also located. One clone encoded 492 amino acids, and the other encoded 516 amino acids. The gene encoding retinal fascin was localized to human chromosome 17, region q24 -25. CONCLUSIONS: These results suggest that retinal fascin may play a role in formation of unique morphologic structures of the photoreceptor cells and is a candidate gene for retinal degenerative disorders.

Actins↗
PubMed2000

Rapid detection of M1S1 mutations by the protein truncation test.

PURPOSE: To determine a method of rapid detection of M1S1 gene mutations in patients with gelatinous droplike corneal dystrophy. METHODS: Forty-one patients from 35 families with gelatinous drop-like corneal dystrophy were studied. The entire coding region of the M1S1 gene was screened using the protein truncation test (PYT), with a polymerase chain reaction fragment amplified from genomic DNA serving as a template of in vitro translation. RESULTS: Homozygous or compound heterozygous mutations were detected in all patients by a single reaction of the PTT. This result matched those obtained using the polymerase chain reaction-restriction fragment length polymorphism and direct sequence analyses. The Q118X mutation was present in 63 of the 70 alleles, accounting for 90% of the disease-associated chromosomes in Japanese patients. CONCLUSIONS: The PTT is useful for detecting mutations in the M1S1 gene. This technique showed that the Q118X mutation is a founder mutation in Japanese patients with gelatinous droplike corneal dystrophy, and it reflects the linkage disequilibrium reported previously.

Antigens, Neoplasm↗
PubMed2000

Mutations in the 11-cis retinol dehydrogenase gene in Japanese patients with Fundus albipunctatus.

PURPOSE: To detect mutations in the RDH5 gene encoding 11-cis retinol dehydrogenase in patients from Japan with fundus albipunctatus. METHODS: Polymerase chain reaction and direct genomic sequencing techniques were used to detect mutations of the RDH5 coding exons (exons 2-5) in two unrelated patients with fundus albipunctatus. Selected alleles that altered the coding region or intron splice sites were evaluated further through segregation analysis in the families of the index cases. RESULTS: Two novel RDH5 mutations were identified. One of these was a missense mutation Val264Gly in exon 5, and the other was an in-frame insertion of 3 bp in exon 5. CONCLUSIONS: The data indicate that mutations in RDH5 are the primary cause of fundus albipunctatus.

Alcohol Oxidoreductases↗
PubMed2000

Preventive effect of local plasmid DNA vaccine encoding gD or gD-IL-2 on herpetic keratitis.

PURPOSE: The goal of this study was to evaluate the effectiveness of a local plasmid DNA vaccine encoding herpes simplex virus (HSV) type 1 glycoprotein D (gD) or gD-interleukin (IL)-2 (chimeric gene of gD and human IL-2) in preventing murine herpetic keratitis. METHODS: Plasmids containing gD (pHSDneo1), gD-IL-2 (pHDLneo1), or vaccine vector (pHSGneo) were injected subconjunctivally with BALB/c mice on days 0 and 7 (90 microgram x 2). Immunization was indicated by positive virus-neutralizing antibody titer, swollen pinna (due to delayed-type hypersensitivity [DTH] reaction), and release of (51)Cr from splenic and/or local cytotoxic effector cells on day 28. In another group of the immunized mice, corneas were challenged with HSV-1 (CHR3 strain, 10 microliter of 3 x 10(6) plaque-forming units [PFU]/ml). Mice were evaluated for clinical signs of epithelial or stromal keratitis on days 1 through 8 and days 10 and 14 or measured on days 2, 4, or 6 for viral titers in the eyes, trigeminal ganglia, and brain. RESULTS: All gD-DNA-injected mice obtained specific immunity. Furthermore, gD-IL-2-DNA elicited a higher DTH reaction and more vigorous cytotoxic effector cell activity. Stromal keratitis scores were lower for all immunized mice compared with control mice, although the difference in epithelial keratitis scores was not statistically significant. Viral titers in eyes, trigeminal ganglia, and brains were suppressed in all immunized mice. CONCLUSIONS: Local immunization with plasmid DNA encoding gD or gD-IL-2 induces humoral and cellular immunity against HSV-1 and inhibits development of stromal keratitis. gD-IL-2 DNA induces greater cell-mediated immunity than gD DNA alone. A plasmid encoding gD-IL-2 is therefore a promising candidate for a vaccine against HSV-1.

Animals↗
PubMed2000

Retinal changes after retinal translocation surgery with scleral imbrication in dog eyes.

PURPOSE: To examine retinal changes induced by scleral imbrication during retinal translocation surgery in dog eyes. METHODS: Fifteen dogs were anesthetized and underwent retinal translocation surgery. After lensectomy and vitrectomy, an intentional retinal detachment was created, and the upper temporal sclera around the equator was imbricated with five mattress sutures. Translocated distances were calculated by pre- and postoperative photographs. At 1, 2, and 4 weeks after the surgery, the retina was studied by TdT-dNTP terminal nick-end labeling (TUNEL) and immunohistochemistry of peanut agglutinin (PNA) lectin and glial fibrillary acidic protein (GFAP). RESULTS: The retina was translocated by a mean distance of 0.53 +/- 0.30 disc diameters or 959 +/- 543 micrometer. Retinal folds were created around the optic disc in all eyes. Histologic examination of the retinal folds 1 week after the surgery showed many TUNEL-positive cells in the outer nuclear layer, loss of photoreceptor cells, and shortening of the outer and inner segments. A strong immunoreactivity to GFAP was detected in the folds of the retina. CONCLUSIONS: . The results demonstrated that retinal translocation surgery by scleral imbrication inevitably caused retinal folds as a postoperative complication, and the retina within the folds showed extensive loss of photoreceptor cells. It is recommended that the foveal translocation surgery be planned to avoid involving the fovea in the retinal folds.

Animals↗
PubMed1999

Expression and polarized distribution of an inwardly rectifying K+ channel, Kir4.1, in rat retinal pigment epithelium.

1. In the eye, different substances and ions including potassium (K+) are transported between neural retina and choroid via the subretinal space. Inwardly rectifying K+ channels (Kir) on the apical membrane of retinal pigment epithelial (RPE) cells are thought to play an essential role in K+ transport in the subretinal space. 2. Single-channel recordings from the apical membrane of RPE cells exhibited functional expression of a Kir channel with properties identical to those of Kir4.1, while recordings from the basolateral membrane showed no detectable Kir channel currents. 3. The expression of Kir4.1 mRNA in RPE cells was confirmed by RT-PCR analysis and in situ hybridization. Furthermore, using immunohistochemistry, we found that Kir4.1 was prominently expressed in RPE cells and localized specifically on the processes on their apical membrane. 4. Developmental studies revealed that expression of Kir4.1 started to appear 10 days or later after birth in RPE cells, in parallel with the maturation of retinal neuronal activity as represented by the a- and b-waves of the electroretinogram. 5. These data suggest that Kir4.1 is one of the Kir channels involved in RPE-mediated control of K+ ions in the subretinal space.

Animals↗
PubMed1999

Prevention of visual field defect after macular hole surgery by passing air used for fluid-air exchange through water.

PURPOSE: To evaluate the effect on peripheral visual field defects occurring after macular hole surgery of passing air that is used for fluid-air exchange through water before infusion to the eye. METHODS: We used Goldmann perimetry to measure the visual fields of patients who underwent vitrectomy to manage idiopathic full-thickness macular holes using either room air or humidified air for fluid-air exchange. We retrospectively studied visual fields measured in 39 patients (group 1) who underwent vitrectomy without humidification of air and prospectively studied visual fields measured in 33 patients (group 2) who consecutively underwent vitrectomy with humidified air for fluid-air exchange. RESULTS: In group 1, nine patients (23%) had peripheral visual field defects, most often located in the inferior or inferotemporal quadrant. No patients (0%) in group 2 had a visual field defect after vitrectomy. The difference between groups 1 and 2 in the proportion of patients with visual field defects after vitrectomy was statistically significant (P = .003). CONCLUSIONS: Passing air used for fluid-air exchange through water seems to prevent visual field defects after vitrectomy for macular hole surgery. Visual field defects that occur after room air is used may result from desiccation of the retina by room air.

Aged↗
PubMed1999

Analysis of vitrectomy for idiopathic macular hole by optical coherence tomography.

PURPOSE: To evaluate foveal structure after vitrectomy for idiopathic macular hole in relation to postoperative visual outcome. METHODS: Optical coherence tomography was performed postoperatively to assess retinal thickness at the foveal center in patients who underwent vitrectomy, posterior hyaloid membrane removal, and perfluoropropane gas tamponade for idiopathic macular hole. Thirty-seven eyes of 36 patients documented to have achieved anatomic hole closure by optical coherence tomography were included in the study. RESULTS: Increased visual acuity significantly correlated with greater foveal thickness assessed at a median of 5 months postoperatively (Spearman analysis; R = .453, P = .005). CONCLUSION: Visual outcome after anatomic closure of macular holes by vitrectomy is closely related to the structure of the center of the fovea postoperatively.

Aged↗