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Biomedical subjects

Emiko Adachi-Usami

Publications and source records attributed to Emiko Adachi-Usami.

At least 19 recordsLinked to original sources
PubMed2006

Up-regulation of genes for oxidative phosphorylation and protein turnover in diabetic mouse retina.

Diabetic retinopathy is one of the most frequent complications of diabetes and is a leading cause of vision loss in adulthood. To better understand the molecular pathophysiology of diabetic retinopathy, we performed comprehensive gene expression analysis of the mouse retina under diabetic conditions with an in-house cDNA microarray system that was designed to be suitable for the small amount of RNA available from a single mouse retina. Diabetes was induced in male C57BL/6 mice by an intraperitoneal injection of streptozotocin, and the changes in retinal mRNA levels were examined in three pairs of diabetic and age-matched control mice at 1 and 3 months after the injection of streptozotocin. Northern blot analysis with amplified total cRNA confirmed the increase in mRNA levels of several selected genes. Most of the significantly up-regulated genes could be classified into two functional categories: oxidative phosphorylation and protein turnover. All mitochondrial DNA-encoded and most of the nuclear DNA-encoded genes for oxidative phosphorylation were up-regulated in the diabetic retina. This was in sharp contrast with a previous report of a down-regulation of these genes in skeletal muscles of streptozotocin-induced diabetic mice and type 2 diabetic humans. Genes for protein synthesis and ubiquitin were also up-regulated in the diabetic retina, suggesting the increase in turnover rates for at least a part of the protein population. Taken together, the diabetic retina appears to be in a state activated for intermediary metabolism, presumably because of an increase in insulin-independent glucose influx. These results provide insights into possible preventive and therapeutic intervention of diabetic retinopathy.

Animals↗
PubMed2006

Histopathological study of a case with branch retinal vein occlusion.

A retinal specimen from a 68-year-old patient with glaucoma and branch retinal vein occlusion was examined by light and electron microscopy. The venous and arterial lumina were filled with erythrocytes, and many erythrocytes extravasated into the venous wall. We suggest that constant rubbing of endothelial cells of the occluded vein results in damage and erythrocyte extravasation was caused by diapedesis.

Aged↗
PubMed2004

Binocular summation in visual evoked cortical potential in patients who have significantly different P100 peak latencies in their two eyes.

PURPOSE: To determine whether binocular summation in visual evoked cortical potential (VEP) is present in patients who have significantly different P100 peak latencies in their two eyes. METHODS: Twelve patients with unilateral optic neuritis (ON) and 11 normal controls were studied. All of them had visual acuity of > or = 20/20 in both two eyes and good stereoacuity. Transient and steady-state VEPs were recorded with monocular and binocular pattern-reversal stimulation. RESULTS: In normal controls, the binocular summation ratio was 1.05 with transient stimulation and 1.21 with steady-state stimulation, and in ON patients it was 1.19 and 1.30, respectively. In ON patients, the peak latency of P100 components was delayed significantly when the affected eye was stimulated, but with binocular stimulation the waveform was very similar to that when the fellow eye was stimulated. CONCLUSION: Binocular summation of VECP is not present in ON cases with large differences in the peak latency between the two eyes even if they have good stereoacuity. Binocular summation may not be correlated with stereopsis in adults whose binocular function has already matured.

Adolescent↗
PubMed2004

Clinical characteristics of Japanese children with optic neuritis.

The clinical characteristics of children with optic neuritis have been reported to be different from that of adults and to vary among different races. To determine the clinical characteristics of Japanese children with optic neuritis, we examined the medical records of 41 children who were diagnosed with optic neuritis at the Department of Ophthalmology of Chiba University Hospital between January 1979 and December 2001. Information on the sex, age of onset, laterality, initial visual acuity, final visual acuity, recent infections and immunizations, and presence of systemic neurologic diseases, such as multiple sclerosis or acute disseminated encephalomyelitis, was obtained. These findings revealed that the clinical features of optic neuritis in children were similar to those reported earlier. The percentage of optic neuritis cases that developed multiple sclerosis in children was similar to that for children in Europe and North America, and this percentage was not lower than that in adults in our clinic. These findings can be taken as the characteristics of optic neuritis of children in Japan.

Adolescent↗
PubMed2003

Adenovirus-mediated gene transfer of Bcl-xL impedes neurite regeneration in vitro.

Mouse retinal explants were transfected with recombinant adenovirus vector carrying the green fluorescent protein (GFP) gene and the rat bcl-xL gene (Adeno-Bcl-xL) to determine its ability to protect retinal ganglion cells against apoptotic cell death and to promote retinal ganglion cell neurite regeneration. Adeno-Bcl-xL-incubated retinas had reduced apoptosis compared to controls. However, neurite regeneration in adeno-treated retinas was less than that of vector-free retina. These results suggest that the usefulness of adenovirus vectors for gene therapy for retinal ganglion cells may be limited.

Adenoviridae↗
PubMed2003

Adenovirus-mediated gene transfer of Bcl-xL impedes neurite regeneration in vitro.

Mouse retinal explants were transfected with recombinant adenovirus vector carrying the green fluorescent protein (GFP) gene and the rat bcl-x(L) gene (Adeno-Bcl-xL) to determine its ability to protect retinal ganglion cells against apoptotic cell death and to promote retinal ganglion cell neurite regeneration. Adeno-Bcl-xL-incubated retinas had reduced apoptosis compared with controls. However, neurite regeneration in adeno-treated retinas was less than that of vector-free retina. These results suggest that the usefulness of adenovirus vectors for gene therapy for retinal ganglion cells may be limited.

Adenoviridae↗
PubMed2003

The effect of caspase inhibitors and neurotrophic factors on damaged retinal ganglion cells.

To elucidate the role of caspase inhibitors and neurotrophic factors in retinal ganglion cell (RGC) death and regeneration, we cultured mouse retinal explants in the presence of caspase-1, -3, -8, or -9 inhibitors, brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF) in serum-free culture media. We quantified apoptosis by TUNEL staining in RGCs and assessed the number of regenerating neurites. Apoptosis of RGCs treated with all caspase inhibitors or with neurotrophic factors was significantly reduced and the number of regenerating neurites was significantly greater than controls (p < 0.05). Our findings indicate that caspase-1, -3, -8, -9 play a critical role in explanted RGC death and may be ideal targets of neuroprotection and regeneration of damaged RGCs.

Animals↗
PubMed2003

Visual field indexes for version 3.0 of frequency doubling perimetry in patients with glaucoma.

PURPOSE: A new version of frequency doubling perimetry was compared to a former version in patients with glaucoma. DESIGN: Prospective observational study. METHOD: Thirty-two patients with glaucoma were examined twice sequentially in one eye with threshold c-20 of frequency doubling perimetry version 2.6. Within 3 months, the same eye was again examined twice sequentially, this time using the new version 3.0. Mean deviation, pattern standard deviation, short-term fluctuation, intraocular pressure at examination, and test duration were compared between versions. RESULTS: No significant difference was found in mean deviation, pattern standard deviation, intraocular pressure, or short-term fluctuation between versions. CONCLUSIONS: Version 3.0 took less time to perform the threshold test than did version 2.6. Version 3.0 of the frequency doubling perimetry program took less time to perform and showed similar values of visual field indexes when compared with version 2.6.

Adult↗
PubMed2003

Accelerated aging of senescence accelerated mice R-1 demonstrated by flash visually evoked cortical potentials.

To determine the physiological alterations of visual functions induced by aging, the latency of the N40 peak of the flash visual evoked cortical potentials at several stimulus frequencies were analyzed from senescence accelerated mice (SAM). The senescence prone (P-8) and senescence resistant (R-1) SAM lines were studied. In both the P-8 and ICR (the standard outbred albino laboratory mouse also called CD-1) mice, the peak latency was not significantly different at 6 and 12 months of age. In contrast, there was a prolongation of the peak latency in the R-1 line at 12 months compared to that at 6 months. We conclude that there is an acceleration of the aging process in the R-1 line for visually evoked responses. Thus, the R-1 line might be an independent line suited for the study of aging effects on visual functions.

Aging↗
PubMed2003

Diagnosis of autosomal dominant retinitis pigmentosa by linkage-based exclusion screening with multiple locus-specific microsatellite markers.

PURPOSE: To describe a hierarchical approach for efficient genetic diagnosis of autosomal dominant retinitis pigmentosa (adRP). METHODS: Forty di-, tri-, or tetra-nucleotide repeats tightly linked to 10 genes known to be responsible for adRP were identified from the human genome sequence and used as markers in multiplex amplification and genotyping, followed by linkage analysis. Discordance of cosegregation of markers and the disease excluded the majority of the examined genes as candidates, and mutation screening for the remaining genes was performed. RESULTS: With this strategy, examination of an adRP-affected family indicated that 3 of 10 candidate genes segregated concordantly with the disease. Further searches for mutations revealed a novel insertion and deletion in the last exon of a splicing factor gene, PRPF8. CONCLUSIONS: This systematic approach facilitates the molecular diagnosis of adRP, which is known to have a highly heterogeneous genetic background.

Carrier Proteins↗
PubMed2002

Citicoline has a protective effect on damaged retinal ganglion cells in mouse culture retina.

Some clinical reports indicate that exogenous CDP-choline (citicoline) may have a therapeutic effect in patients with glaucoma. However, the precise effect of citicoline on damaged retinal ganglion cells (RGCs) remains to be explained. We performed tissue culture of mouse retinal explants and investigated the effect of citicoline on damaged RGCs by the quantitative analysis of TdT-dUTP terminal nick-end labeling (TUNEL) staining and the assessment of the number of regenerating neurites. The TUNEL-positive ratio in 0.1-10 micromol/l citicoline-treated retina was very low, and the number of regenerating neurites increased more than in control retina. Our findings suggest that citicoline has a protective effect on damaged RGCs in tissue culture of retina.

Animals↗
PubMed2002

Learning effect for frequency doubling perimetry in patients with glaucoma.

PURPOSE: We studied the results obtained by repeated frequency doubling perimetry in patients with glaucoma and demonstrated a learning effect. METHODS: Prospective observational study. Thirty-three patients who had glaucoma and had never experienced frequency doubling perimetry participated in this study. The patients were examined by frequency doubling perimetry three times within 6 months. Mean deviation, pattern standard deviation, and intraocular pressure at examination were compared among three results. RESULTS: On frequency doubling perimetry, the mean deviation results of the first, second, and third tests were -7.96 dB, -7.29 dB, and -7.36 dB, respectively. The first and second results and the first and third results were significantly different (P = 0.029 and P = 0.049, respectively). No significant differences with regard to pattern standard deviation and intraocular pressure were noted. CONCLUSION: A positive learning effect was found for frequency doubling perimetry in the first and second mean deviation results of patients with glaucoma.

Adult↗
PubMed2002

Rescue of axotomized retinal ganglion cells by BDNF gene electroporation in adult rats.

PURPOSE: To determine whether the brain-derived neurotrophic factor (BDNF) gene can be transfected into retinal ganglion cells (RGCs) by electroporation and whether axotomized RGCs can be rescued after transfection by BDNF in adult rats. METHODS: Mouse BDNF cDNA was injected intravitreally followed by in vivo electroporation in adult rats. The expression of BDNF in RGCs was confirmed by Western immunoblot analysis and immunohistochemistry. After introduction of BDNF cDNA, the survival of axotomized RGCs was estimated by the TdT-dUTP terminal nick-end labeling (TUNEL) method and measured by counting the number of RGCs that were labeled retrogradely by 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyamine percholorate (diI) applied to the superior colliculus (SC). RESULTS: Eyes with injection of the BDNF gene followed by in vivo electroporation showed a significantly higher level of expression of BDNF in the RGC layer, a higher rescue ratio, and a lower number of TUNEL-positive cells than the control samples. CONCLUSIONS: These findings demonstrate that electroporation is an effective method for the direct delivery of genes into RGCs, and that the BDNF gene transferred into RGCs by in vivo electroporation can protect axotomized RGCs against apoptosis.

Animals↗
PubMed2002

The role of c-fos in cell death and regeneration of retinal ganglion cells.

PURPOSE: To investigate the effect of c-fos on apoptotic cell death and regeneration of damaged retinal ganglion cells (RGCs) in tissue culture of retinal explants. METHODS: Retinas from transgenic mice carrying the exogenous c-fos gene under the control of the interferon (IFN)-alpha/beta inducible Mx-promoter (Mx-c-fos), c-fos-deficient mice, and littermate control mice were dissected and cultured in a three-dimensional collagen gel culture system, followed by an analysis of TdT-dUTP terminal nick-end labeling (TUNEL) staining and measurement of neurites that emerged from explants. RESULTS: Compared with littermate control mice, Mx-c-fos transgenic animals showed a higher ratio of TUNEL positivity in the RGC layer from early in the culture period that correlated with the small number of regenerating neurites. In contrast, the c-fos-null mutated mice showed a still-lower ratio of TUNEL-positive cells. Nevertheless, the number of regenerating neurites was significantly lower in the initial phase, although the drastic increase in density of neurite regeneration was observed in the late period of culture. CONCLUSIONS: These findings suggest that c-fos is involved in both apoptotic cell death and regeneration of damaged RGCs. Elucidation of the precise c-fos-mediated cascade involved in RGC apoptosis and regeneration is significant in realizing neuronal survival and regeneration.

Animals↗
PubMed2002

Binocular interaction reflected in visually evoked cortical potentials as studied with pseudorandom stimuli.

PURPOSE: To study the interaction of visual signals from both eyes with visual evoked cortical potentials (VECPs) elicited by pseudorandom binary sequence (PRBS) stimuli. METHODS: A PRBS was used to drive two independent LED arrays to elicit VECPs. The right and left eyes were simultaneously stimulated by two different series of PRBS stimuli. The impulse response function of each eye was calculated from the raw data by cross-correlating the PRBS and the response. The effect of changing the luminosity of the LEDs parametrically on the responses obtained from the two eyes was evaluated. RESULTS: The impulse response, obtained from 10 volunteers with normal vision, had characteristics similar to responses to the conventional VECP, with a major positive peak at 110 ms (P110). When two eyes were bilaterally exposed to two PRBS stimuli of the same luminosity, the P110 amplitudes of both eyes were decreased by the same amount from that obtained by stimulating only one eye. When the luminosity in the two eyes was different, the VECP amplitude in the eye with the dimmer stimuli decreased, and the amplitude in the contralateral eye increased. CONCLUSIONS: The results clearly demonstrate that interocular luminance interaction can be detected electrophysiologically in normal subjects by using PRBS- driven stimuli in which the feasibility of recording response from the two eyes independently.

Adult↗
PubMed2002

Effect of body temperature on electroretinogram of mice.

PURPOSE: To investigate the ERG alterations induced by changes in body temperature in mice. METHODS: Three-week-old BALB/c mice were used. Rectal temperature was measured with a digital thermometer and taken as the body temperature. In experiment 1, the body temperature was kept at 33 degrees C, and the ERGs elicited by a constant stimulus intensity were recorded every 5 minutes. In experiment 2, the body temperature was lowered in five steps from 38 degrees C to 33 degrees C, 28 degrees C, 23 degrees C, and 18 degrees C. At each body temperature, ERGs elicited by different stimulus intensities were recorded. RESULTS: In experiment 1, the mean amplitudes and implicit times of both the a- and b-waves did not change significantly. In experiment 2, the amplitude of both the a- and b-waves decreased significantly with a decrease in body temperature, and the implicit times of the a- and b-waves were prolonged with a decrease in body temperature. CONCLUSIONS: Body temperature greatly affects the amplitude and timing of the ERG. Great care must be taken to maintain as normal a body temperature as possible when using the ERG to evaluate the retina, especially in small animals such as mice.

Animals↗
PubMedDate not supplied

Comparison of Yatabe-Guilford personality test results in retinitis pigmentosa and glaucoma patients.

PURPOSE: To determine the psychological state and personality traits of patients with retinitis pigmentosa (RP) or glaucoma so that a closer and better relationship can be developed with the patients. METHODS: The Yatabe-Guilford personality test was administered to 75 RP patients and 42 glaucoma patients. The latter group included 29 cases of primary open-angle glaucoma, 6 of primary angle-closure glaucoma, and 7 of normal-tension glaucoma. The patients were being treated at the Department of Ophthalmology, Chiba University Hospital. As controls, 47 age-matched volunteers were tested. RESULTS: A comparison of these three groups showed that the proportions of patients with cyclic tendency, rhathymia, and lack of cooperativeness traits were significantly higher in the RP group than in the glaucoma group. The lack of cooperativeness value was especially higher in the RP than in the glaucoma group and the control group (Fisher exact test, P <.05). On the other hand, the nervousness value was significantly higher in the glaucoma group than in the RP group and than in controls (Fisher exact test, P <.05). Factors of sex, age, type of disease, corrected visual acuity, and central visual fields did not influence the profiles of the RP and glaucoma groups. CONCLUSION: RP patients had relatively well-stabilized personalities and were optimistic, while glaucoma patients tended toward nervousness in comparison with RP patients and controls.

Adult↗