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Biomedical subjects

Haruki Abe

Publications and source records attributed to Haruki Abe.

At least 19 recordsLinked to original sources
PubMed2006

Negative scotopic ERG and photopic ERG ON response impairment in a patient with normal dark adaptation.

PURPOSE: To present ocular findings in a patient who showed negative scotopic electroretinogram (ERG) and reduced ON response, but normal dark adaptation. CASE: An 18-year-old Japanese male patient who complained of severe asthenopia. His corrected visual acuities were 1.2 in both eyes. His fundi were normal. He had normal contrast sensitivity and normal dark adaptation. METHODS: The patients underwent ERG (including the standard protocol and photopic long flash recordings). RESULTS: The amplitudes of the rod ERG b-wave were reduced. The scotopic standard combined ERG response showed negative configuration. The photopic response to long flash revealed the reduced b-wave (ON response), while the amplitude of the first peak of the d-wave (OFF response) was within the normal range. CONCLUSIONS: Postsynaptic abnormalities in both the rod and cone ON-pathways, which are often found in patients with night blindness, were suggested in the ERG findings, but the dark adaptation of our patient was normal. Neuromuscular evaluation of the patient and ophthalmological evaluation, including ERG, of his parents were normal. To our knowledge, the ophthalmological and electrophysiological findings of our patient cannot be attributed to any known clinical entity.

Adaptation, Ocular↗
PubMed2006

Risk factors for open-angle glaucoma in a Japanese population: the Tajimi Study.

PURPOSE: To identify the risk factors associated with primary open-angle glaucoma (POAG) in the Tajimi Study. DESIGN: Population-based cross-sectional epidemiologic study. PARTICIPANTS: One hundred nineteen POAG patients and 2755 controls. METHODS: Univariate and multivariate comparison of ocular factors and systemic factors between POAG patients and controls. MAIN OUTCOME MEASURES: Difference in factors between POAG patients and controls, factors associated with POAG patients, and their odds ratio (OR). RESULTS: Intraocular pressure (IOP), age, myopia, and history of hypertension differed between POAG patients and controls in univariate analyses. Multivariate analysis with logistic regression with stepwise selection of variables demonstrated that higher IOP (OR, 1.12 [95% confidence interval (CI), 1.04-1.21]), myopia (ORs, 1.85 [95% CI, 1.03-3.31] for low myopia and 2.60 [95% CI, 1.56-4.35] for moderate to high myopia), and older age (OR, 1.06 [95% CI, 1.04-1.08]) were associated with an increased risk of having POAG. CONCLUSIONS: Although the majority (92%) of POAG patients diagnosed in the Tajimi Study had IOP within the normal range, IOP was still identified as a significant risk factor for POAG. Together with IOP, myopia and age were significant risk factors for having POAG.

Age Factors↗
PubMed2006

Night blindness with depolarizing pattern of ON/OFF response in electroretinogram: a case report.

PURPOSE: To present a patient who has night blindness with a depolarizing pattern of ON/OFF response by electroretinography (ERG). CASE: A 43-year-old woman had had night blindness and poorly corrected visual acuity since childhood. Parental consanguinity was noted. The patient had suffered from mental retardation, epilepsy, and mild cerebellar ataxia. Corrected visual acuity was 20/30 in the right eye and 20/25 in the left. Goldmann perimetry showed no scotoma but slight depression with internal isoptors. No evidence for rod activity was observed by Goldmann-Weekers adaptometry. The ocular fundi appeared normal. METHODS: Conventional full-field ERGs to scotopic (dim and bright flash) and photopic (bright flash and flicker) stimuli were recorded. Photopic ERG responses to long flash stimulation (200 ms) were also examined. RESULTS: The scotopic responses to dim flash were non-recordable, while those to bright flash were severely reduced. The photopic responses to bright flash were decreased. The amplitudes of flicker responses also were significantly decreased, and the implicit times of those responses were prolonged. Although the amplitudes of a- and d-waves to long flash stimulation were reduced, those of the b-wave were within normal range. The implicit times of a-, b- and d-waves were significantly prolonged. The patient showed a normal rise for the photopic b-wave but lacked a normal falling slope after the b-wave peak. An OFF-response late-negativity was also noted. CONCLUSIONS: The abnormal ON/OFF response found in the patient could be diagnosed as depolarizing pattern, characterized by elevation of the plateau to a positive potential above the prestimulus baseline. Since the ERG waveforms and clinical features found in our patient were different from those in previous reports, her ERG findings might reflect another retinal physiological mechanism.

Adult↗
PubMed2006

Visual cortical contribution to open-loop and feed-back control of convergence eye movements in the cat.

Open-loop and closed loop controls in convergence eye movement have been reported by human psycho-physical studies. To investigate the visual cortical involvement in open-loop convergence eye movement, we trained a cat to elicit anticipatory convergence (convergence eye movement before the onset of target movement) by using an approaching visual target with a preceding alarm signal. After 1-2 weeks of training, anticipatory convergence was observed in more than half of the trials in seven cats. The frequency of occurrence of anticipatory convergence was significantly decreased after electrocoagulation in the convergence-related region of the lateral suprasylvian (LS) area, an extrastriate visual cortex of the cat. On the other hand, the localized injection of Muscimol, a GABA-A agonist, reduced visually evoked convergence, but caused no significant effects to anticipatory convergence. These differential results suggest that the LS plays a role in both open-loop and feed-back control of convergence eye movement, and a GABA-A sensitive subregion is involved in the feed-back control of convergence eye movement.

Animals↗
PubMed2006

Assessment of axonal degeneration along the human visual pathway using diffusion trace analysis.

PURPOSE: The effectiveness of diffusion trace value analysis for non-invasive assessment of retinal ganglion cell (RGC) axonal degeneration at multiple anatomic levels along the human visual pathway under clinical setting was evaluated. DESIGN: Imaging study. METHODS: Ten patients with unilateral chronic optic neuropathy of varying cause and 16 age-matched normal subjects were studied. Trace, a tensor invariant that is considered to be a sensitive index for pathologic changes in axons, was analyzed at nine anatomic sites in each subject, namely, bilaterally at the level of the optic nerves, uncrossed chiasmal fibers, optic tracts and optic radiations, and crossed chiasmal fibers, using a 3.0 Tesla magnetic resonance imaging system. RESULTS: Trace values of the optic nerve and uncrossed chiasmal fibers ipsilateral to the affected eye, the crossed chiasmal fibers, and optic tracts bilaterally were significantly higher than those of the corresponding anatomic sites in normal subjects. The optic nerve and uncrossed chiasmal fibers ipsilateral to the unaffected side and optic radiations, bilaterally, had trace values which were not significantly different from the values of the corresponding anatomic levels in normal subjects. The increase in trace value in the optic nerve and uncrossed chiasmal fibers ipsilateral to the affected side was greater than those of the crossed chiasmal fibers and optic tracts. CONCLUSIONS: Findings are highly consistent with a degenerative process of RGC axons and trace values are quantitatively well correlated to predicted pathology at the given anatomical sites. Trace value measurement at multiple sites along fiber pathways appears to be a powerful addition to clinical assessment of the functionality of components of the visual pathways during various stages of a pathologic process.

Adult↗
PubMed2006

Pupillography of relative afferent pupillary defect contralateral to monocular mature cataract.

CASE REPORT: Few previous reports have documented a relative afferent pupillary defect (RAPD) in the eye contralateral to a dense unilateral cataract. We report pupillographic findings of a 55-year-old man with a mature cataract in the left eye and an RAPD in the right eye, whose RAPD disappeared after cataract surgery in his left eye. Using binocular infrared video pupillography, we recorded the pupillary responses of the two eyes simultaneously during an automated swinging flashlight test before and after the cataract surgery. The average contraction amplitude in both eyes was significantly larger when the unaffected left eye was stimulated before the cataract surgery, but this difference in contraction amplitude disappeared after surgery on the left eye. COMMENTS: An RAPD was shown quantitatively with a pupillographic technique in the eye contralateral to a mature cataract, confirming previous studies that indicate a dense cataract may produce a small but definite RAPD in the contralateral eye. Such an RAPD associated with a dense cataract must be taken into consideration when evaluating patients with unilateral visual loss.

Cataract↗
PubMed2006

Effect of the background on the disparity-induced ramp vergence response in humans.

PURPOSE: Our purpose was to investigate the changes in the dynamic property of vergence eye movements caused by changes in the co-existing stationary background in the central visual field. METHODS: Disparity-driven target movement was presented virtually by a head-mounted liquid-crystal display. Two targets were used: a bar-shaped target that moved between 2 and 0.5 m along the mid-sagittal line at a speed of 50 cm/s (vergence target) and a background image of a cross-shaped target that stayed at a distance of 2 m (background target). Eight normal subjects participated in the experiments. The subject was asked to follow the vergence target while the configuration of the background target was randomly changed among four conditions in each experiment: the length (experiment 1) or the width (experiment 2) of the horizontal and vertical lines composing the cross of the background target was each randomly changed among four conditions. A limbus tracker was used to measure eye movements. RESULTS: In experiment 1, there was a negative correlation between the amplitude of the vergence eye movements and the lengths of the lines of the cross in each of five subjects (mean r = 0.018, n = 48 in each subject). Similarly, in experiment 2, there was a negative correlation between the amplitude of the vergence eye movements and the width of the lines of the cross in each of 8 subjects (mean r = -0.12, n = 48 in each subject). CONCLUSION: The vergence response to a target object significantly differs depending on the texture of background objects on the visual axis.

Adult↗
PubMed2005

Müller Cells as a source of brain-derived neurotrophic factor in the retina: noradrenaline upregulates brain-derived neurotrophic factor levels in cultured rat Müller cells.

Müller cells, the predominant glial cells in the retina, are thought to play important roles in the survival of retinal neurons. Previous studies have demonstrated that Müller cells express brain-derived neurotrophic factor (BDNF), which has a pronounced neurotrophic effect on retinal ganglion cells. In this study, we investigated whether Müller cells express and release BDNF in culture. Reverse transcriptase-PCR, immunocytochemistry and Western blotting revealed that Müller cells produce BDNF mRNA and protein. Using the enzyme-linked immunosorbant assay, BDNF protein levels in Müller cells and their conditioned medium were quantified, demonstrating that Müller cells produce and release high levels of BDNF. Noradrenaline administration caused an upregulation of BDNF mRNA and protein expression by cultured Müller cells. These results suggest that Müller cells may act as an endogenous source of BDNF in the retina. Furthermore, induction of BDNF expression by adrenergic agonists may provide a therapeutic approach to retinal neurodegenerative disorders.

Animals↗
PubMed2005

Near-infrared spectroscopy of the visual cortex in unilateral optic neuritis.

PURPOSE: To examine the occipital-lobe activation of patients with optic neuritis using near-infrared spectroscopy. DESIGN: Experimental study. METHODS: NIRS was performed on five patients with acute unilateral optic neuritis during monocular visual stimulation. As controls, six normal subjects were also tested in the same manner. RESULTS: In the patients with optic neuritis, the changes in the hemoglobin concentrations (oxyhemoglobin, deoxyhemoglobin, and total hemoglobin) in the occipital lobe were found to be markedly reduced when the clinically affected eyes were stimulated compared with the fellow eyes. The response induced by the stimulation of the affected eye was decreased, even when the patient's visual acuity improved to 20/20 in the recovery phase. There was no difference in the concentration changes between the two eyes in the control subjects. CONCLUSIONS: NIRS may be useful in detecting visual dysfunction objectively and noninvasively in patients with visual disturbance, especially when used at the bedside.

Adolescent↗
PubMed2005

The Tajimi Study report 2: prevalence of primary angle closure and secondary glaucoma in a Japanese population.

PURPOSE: To determine the prevalence of primary angle-closure glaucoma (PACG), secondary glaucoma (SG), and all glaucoma in a Japanese population as a part of the Tajimi Study. DESIGN: Population-based epidemiological survey. PARTICIPANTS: A random sample of residents 40 years or older from Tajimi, Japan. INTERVENTION: Each subject underwent a screening program comprising an interview and an ophthalmic examination, including Goldmann applanation tonometry, slit-lamp examination, a van Herick test, fundus photography, and a screening visual field (VF) test using frequency-doubling technology. If glaucoma was suspected, the subject was referred for a definitive examination that included slit-lamp examination, gonioscopy, intraocular pressure measurement, a VF test, and optic disc and fundus examination. A diagnosis of PACG or SG was made based on slit-lamp examination, gonioscopy, optic disc appearance, and perimetric results. MAIN OUTCOME MEASURES: Prevalences of PACG, SG, and all cases of glaucoma. RESULTS: Of 3870 eligible people, 3021 (78.1%) participated in the study. Estimated prevalences of PACG and SG in those over 40 years were 0.6% (95% confidence interval [CI], 0.4%-0.9%) and 0.5% (95% CI, 0.2%-0.7%), respectively. Prevalences of all glaucoma and glaucoma/suspected glaucoma were estimated to be 5.0% (95% CI, 4.2%-5.8%) and 7.5% (95% CI, 6.5%-8.4%), respectively. CONCLUSIONS: Prevalences were 0.6%, 0.5%, and 5.0%, respectively, for PACG, SG, and all glaucoma in subjects over 40 years from Tajimi, Japan.

Adult↗
PubMed2005

Measurement of intraocular pressure using the NT-4000: a new non-contact tonometer equipped with pulse synchronous measurement function.

PURPOSE: NT-4000 (Nidek Co. Ltd., Gamagori, Japan) is a new non-contact tonometer (NCT) equipped with pulse synchronous measurement function that can measure intraocular pressure (IOP) synchronized with the ocular pulse. The purpose of this study was to evaluate the usefulness of NT-4000 in normal subjects and in patients with glaucoma and ocular hypertension. METHODS: This study included 175 eyes of 175 subjects. Firstly, the IOP was measured using NT-4000 without the pulse synchronous measurement function (NTn). Secondly, the IOP at peak, middle, and trough phases of the pulse signal were measured using NT-4000 with the pulse synchronous measurement function (NTp, NTm, NTt, respectively). Additionally, the IOP was measured with Goldmann applanation tonometer (GT). The coefficient of variation (CV) of three readings in the NCT measurements was used to evaluate the intra-session reproducibility. Statistical comparisons were performed using Wilcoxon signed rank test and one-way analysis of variance with Scheffe's test. Linear regression analysis was used to calculate correlation coefficients. P values less than 0.05 were accepted as statistically significant. RESULTS: The CV of NTn, NTp, NTm, and NTt were 6.4%, 5.5%, 4.9%, and 5.2%, respectively. The CV of NTp, NTm, and NTt were significantly smaller than that of NTn (P = 0.007, P < 0.001, P < 0.001, respectively). NTp was significantly higher than NTt (P = 0.038). GT was significantly correlated with NTn, NTp, NTm, and NTt (r = 0.898, P < 0.001; r = 0.912, P < 0.001; r = 0.908, P < 0.001; r = 0.900, P < 0.001, respectively). CONCLUSION: NT-4000 can detect the fluctuation of IOP associated with the ocular pulse.

Adult↗
PubMed2005

[Evaluation of macula in patients with branch retinal vein occlusion using multifocal electroretinogram and optical coherence tomography].

PURPOSE: To evaluate the functions of the macular area in patients with branch retinal vein occlusion (BRVO) by using multifocal electroretinograms (mERG) and optical coherence tomography(OCT). METHODS: mERGs were recorded from 18 eyes of 18 patients with BRVO. An array of 103 hexagonal elements was displayed on a monitor. The latency (ms) and response density (nV/deg2) of mERGs were measured for 7 central locations. The peak and troughs were labeled N1, P1 and N2, respectively. OCT was used to measure the foveal retinal thickness. RESULTS: Statistically significant correlation was found between visual acuity(log MAR) and P1-N1 response density (r = - 0.629, p < 0.05) and N2 latency(r = 0.619, p < 0.05). Foveal retinal thickness had the significant statistic correlations with P1-N1 response density (r = -0.750, p < 0.0001), P1-N2 response density (r = -0.520, p < 0.05) and N2 latency (r = 0.488, p < 0.05). CONCLUSIONS: In 18 BRVO patients, mERGs from the central retinal area were significantly correlated with foveal retinal thickness measured by OCT and with visual acuity. The mERG recording is sensitive to morphological changes and functional disorders induced by BRVO.

Aged↗
PubMed2005

[Multifocal visually evoked responses in two children with optic neuritis].

PURPOSE: Central visual functions of two children with idiopathic optic neuritis were analyzed and followed in the course of the disease by using multifocal visually evoked potentials (mVEP) and other ophthalmological tests. SUBJECTS AND METHODS: Two girls 10 and 11 years of age with unilateral optic neuritis participated in this study. At the initial onset of the disease, visual acuity of the patients was below 20/400 and severe central visual field impairment was found in the affected eyes. There were no abnormal neurological or radiological findings suggesting multiple sclerosis in these patients. The mVEPs were recorded with a stimulus of 37 hexagons composed of black and white triangles subtending 35 degrees of visual angle. RESULTS: The amplitude of mVEPs from many stimulating locations was severely reduced in the course of the recovery of these patients. Although visual acuity and perimetric sensitivity in the affected eyes recovered to normal after steroid pulse therapy, the amplitude of mVEPs still remained 1/3 to 1/2 of that of the opposite healthy eye. The mVEPs gradually recovered to near the level of the opposite healthy eyes at the latest examination. CONCLUSIONS: Recovery from the central visual impairment due to infantile optic neuritis is more gradual than that suggested by subjective ophthalmological examinations. There is still optic nerve dysfunction after visual acuity and visual field have recovered to normal. The mVEP is one of the most sensitive tools for detecting optic nerve dysfunction in patients with optic neuritis.

Child↗
PubMed2004

Mutations in the gene coding for guanylate cyclase-activating protein 2 (GUCA1B gene) in patients with autosomal dominant retinal dystrophies.

BACKGROUND: We investigated mutations in the gene coding for guanylate-cyclase activating protein 2 (GCAP2), also known as GUCA1B gene, in Japanese patients with retinitis pigmentosa (RP) and tried to identify phenotypic characteristics associated with mutations in the gene. SUBJECTS AND METHODS: Genomic DNA samples from 63 unrelated patients with autosomal dominant retinitis pigmentosa (ADRP) and 33 patients with autosomal recessive retinitis pigmentosa (ARRP) were screened by single-strand conformational polymorphism analysis followed by direct sequencing. Clinical features associated with a mutation were demonstrated by visual acuity, visual field testing, fundus photography, and electroretinography. RESULTS: A novel transitional mutation converting GGA to AGA at codon 157 (G157R) was identified. This mutation has been found in three index patients from three independent families. Phenotypic examination of seven members of the three families revealed that this mutation was associated with RP with or without macular involvement in five members, macular degeneration in one member, and asymptomatic normal phenotype in one member. In addition, previously unknown polymorphic changes including V29V, Y57Y, T87I, and L180L were identified. CONCLUSIONS: A racial difference exists in the spectrum of mutations and/or polymorphisms in the GCAP 2 gene between British and Japanese populations. Our findings suggest that the mutation in the GCAP 2 gene can cause one form of autosomal dominant retinal dystrophy, with variable phenotypic expression and incomplete penetrance.

Adult↗
PubMed2004

The prevalence of primary open-angle glaucoma in Japanese: the Tajimi Study.

PURPOSE: To assess the prevalence of primary open-angle glaucoma (POAG) and its association with intraocular pressure (IOP) in Tajimi City in central Japan. DESIGN: A cross-sectional epidemiologic study in a defined population. PARTICIPANTS: Subjects randomly selected from the population older than 40 years in Tajimi City. INTERVENTION: Each subject underwent a screening examination comprised of an interview and ophthalmic examinations, including measurement of IOP by a Goldmann applanation tonometer, central corneal thickness (CCT), slit-lamp examination, fundus photography, and a screening visual field test using frequency doubling technology. When ocular diseases were suspected, the subjects were referred for definitive examination. During the definitive examination, slit-lamp examination, IOP measurement, a visual field test using Humphrey Field Analyzer 30-2 SITA Standard program (Humphrey Instruments, San Leandro, CA), optic disc and fundus examination, and gonioscopy were performed and stereoscopic disc photographs were obtained. A diagnosis of glaucoma was made based on optic disc appearance, perimetric results, and other ocular findings. MAIN OUTCOME MEASURES: Prevalence of POAG, mean IOP, and mean CCT. RESULTS: Of 3870 eligible people, 3021 (78.1%) participated in the study. The estimated prevalence of POAG in the population older than 40 years was 3.9% (95% confidence interval [CI]), 3.2%-4.6%). The prevalence of cases of POAG with IOP levels of 21 mmHg or less was 3.6% (95% CI, 2.9%-4.3%), whereas the prevalence for those with IOP levels of more than 21 mmHg was 0.3% (95% CI, 0.1%-0.5%). The average IOP for eyes with POAG was 15.4+/-2.8 (standard deviation) in the right eye (n = 115) and 15.2+/-2.8 mmHg in the left eye (n = 115), which was significantly higher than that of nonglaucoma subjects (14.5+/-2.5 in the right eye; n = 2759; P = 0.0004; and 14.4+/-2.6 mmHg in the left eye; n = 2757; P = 0.0026). The mean CCT of POAG eyes with IOP levels of 21 mmHg or less was 518+/-29 (n = 109) in the right eye and 519+/-29 microm (n = 110) in the left eye, levels that were not significantly different from that of nonglaucoma eyes (520+/-32 microm [n = 2690]; and 522+/-32 microm [n = 2692]; P>0.05). CONCLUSIONS: The prevalence of POAG in this population was 3.9%. In 92% patients with POAG, the IOP was 21 mmHg or less.

Adult↗
PubMed2004

Statistical evaluation of the diagnostic accuracy of methods used to determine the progression of visual field defects in glaucoma.

OBJECTIVE: To evaluate trend-type analyses to judge the progression of visual field damage (VFD) of glaucoma in terms of ratios of making judgments of progression and specificity, and to report a new method. DESIGN: Retrospective analysis of visual field (VF) results of actual glaucoma cases and those simulated by computer, and receiver operating characteristic curve analysis of performance of methods to judge the progression of VFD. PARTICIPANTS: One hundred five eyes of 105 open-angle glaucoma (OAG) patients with progressing VFD and 355 eyes of 355 clinically stable OAG patients for VF simulation from 4 university-based referral practices. METHODS: Methods using regression analysis of total deviation (TD), mean deviation (MD), mean TD of a sectored VF, and original scoring used in the Advanced Glaucoma Intervention Study (AGIS) were compared. A VF test was repeated twice in a short period on the 355 stable OAG eyes, and test-retest fluctuation, including variance at each test point and covariance between 2 test points, was calculated to simulate stable glaucomatous VF series by computer. The sensitivity of each method was calculated with 105 progressing VF series, and specificity was calculated with 10,000 simulated stable glaucomatous VF series. MAIN OUTCOME MEASURES: Sensitivity (ratios of making judgments of progression), specificity, and diagnostic power. RESULTS: The methods using the TD slope on one test location showed a sensitivity of 0.848 to 1.000, with a specificity of 0.105 to 0.721, and on 2 adjacent test locations showed a sensitivity of 0.848, with a specificity of 0.722. A significant negative MD slope with P<0.05 showed a sensitivity of 0.524, with a specificity of 0.945. The method using a sectored VF showed a sensitivity of 0.695, with a high specificity of 0.946. The AGIS method showed a sensitivity of 0.305 to 0.467, with a very high specificity of 0.999 to 1.000. The method using previously reported mathematically sectored VFs showed a sensitivity of 0.790, with a specificity of 0.900, and higher diagnostic power (1.69) than the others in this study population. CONCLUSIONS: Most of the methods using the TD slope were characterized by high sensitivity, the AGIS method had a very high specificity, and those using VF sectors had reasonable sensitivity and specificity.

Adolescent↗
PubMed2004

ERG rod a-wave in Oguchi disease.

We analyzed the change in the ERG rod a-wave waveform during the course of dark adaptation in two patients with Oguchi disease. Two Japanese patients showed a homozygous arrestin 1147delA mutation. Scotopic flash ERGs were recorded after different periods of dark adaptation. ERG rod a-waves were obtained after subtraction of the cone ERG contribution. The rod a-waves were fitted with a model of the rod receptor signal. The parameters, Rm(p3) (maximum a-wave amplitude) and S (sensitivity) were calculated. Longer periods in the dark produced larger rod a-wave but only to the first flash presented. The amplitude of the response to subsequent flashes was essentially independent of the period of dark adaptation. Rm(p3) increased with advance of dark adaptation. However, S was nearly constant. Our results suggest that the cause of delayed dark adaptation is not to be sought in the activation of phototransduction process or the regeneration of rhodopsin per se but rather in the deactivation process of the phototransduction cascade.

Dark Adaptation↗