Publications by authors named "Yutaka Tazawa"
Article Synopsis
- - The study investigates how limb amputation combined with intensive motor practice affects the brain's sensorimotor cortex, focusing on a Paralympic long jumper with a below-knee amputation who trained using a prosthesis.
- - Findings show that this athlete activated both sides of the sensorimotor cortex more than healthy long jumpers during knee muscle contractions with his prosthetic leg, indicating unique brain adaptations due to his training and limb loss.
- - The results highlight the brain's ability to reorganize itself functionally after significant changes like amputation and extensive training, suggesting that motor rehabilitation can lead to significant cortical plasticity.
Purpose: To characterize the s-wave of the multifocal electroretinogram (mfERG) in cats, and to determine the contribution of the inner retina to the s-wave by examining the effects of tetrodotoxin (TTX) and N-methyl D: -aspartate (NMDA) injected into the vitreous cavity.
Methods: mfERGs were recorded from 15 eyes of 15 male cats under general anesthesia. The stimulus consisted of 37 elements, and the luminance of the bright and the black elements were 200 and 4 cd/m2, respectively.
Purpose: To determine whether myopia is more prevalent in Japanese patients with idiopathic focal subretinal neovascularization (IFSN) than in normal control subjects.
Methods: Forty-seven eyes of 46 patients with an initial diagnosis of IFSN and 291 eyes of 291 controls were studied. Refractive errors were measured with an autorefractometer, and the spherical equivalent of the refractive error was used for the statistical analyses.
Purpose: To determine whether a significant correlation exists between the amplitude of the s wave of the multifocal electroretinogram (mfERG) and the retinal nerve fiber layer thickness (RNFLT) in glaucomatous eyes.
Methods: Twenty-three eyes of 23 patients with glaucoma were studied. In all eyes, the severity of the defects in the upper visual field differed significantly from the severity of those in the lower half.
Purpose: To determine the functional changes in the rod and cone pathways after photoreceptor loss by continuous light exposure.
Methods: Fifty-four male Sprague-Dawley rats were exposed to diffuse fluorescent light of 2000 lux for 24 or 48 hr. Two weeks after the light exposure, full-field scotopic and photopic electroretinograms (ERGs) were elicited by different stimulus intensities with a maximum luminance of 0.
Purpose: To determine possible mechanisms that shape the negative electroretinograms (ERGs) in rats with photoreceptor degeneration induced by destruction of the retinal pigment epithelium.
Methods: Sprague-Dawley rats (n = 48) were injected intravenously with 60 mg/kg of sodium iodate (NaIO(3)). Full-field ERGs were elicited by different stimulus intensities with a maximum luminance of 1.
Purpose: To investigate the relationship between retinal function and histopathology following retinal ischemia-reperfusion in rats.
Methods: Retinal ischemia was induced in 27 Sprague-Dawley rats by raising the intraocular pressure for 60- or 90-minutes. Two weeks after the retinal ischemia-reperfusion, ganzfeld stimuli of different luminances (maximum 0.
Neuroprotective effect of hepatocyte growth factor against photoreceptor degeneration in rats.
Invest Ophthalmol Vis Sci
November 2004
Purpose: To determine whether hepatocyte growth factor (HGF) has a neuroprotective effect against photoreceptor degeneration in rats.
Methods: Eight-week-old Sprague-Dawley (SD) and 24-day-old Royal College of Surgeons (RCS) rats received an intravitreal injection of HGF in the right eyes. The left eyes were injected with vehicle and served as the control.
Background: Birdshot chorioretinopathy, acute posterior multifocal placoid pigment epitheliopathy, and retinal pigment epithelial detachment have been reported as rare manifestations associated with sarcoidosis, suggesting that ocular sarcoidosis may affect the choroidal circulation. We report a case of ocular sarcoidosis representing a choroidal circulatory disturbance without the appearance of retinal lesions or loss of retinal function.
Case: A 20-year-old woman was referred with blurred vision in the left eye.
Purpose: To determine the sensitivity of the blue cone system by static perimetry in patients with unilateral acute idiopathic blind spot enlargement (AIBSE) syndrome.
Design: Observational case series.
Methods: Four patients with AIBSE syndrome, aged 16 to 30 years, were studied.
Purpose: To determine whether the amplitude of the s-wave on a multifocal electroretinogram (mfERG) is correlated with the degree of visual field depression in eyes with glaucoma.
Methods: Twenty patients (20 eyes) with glaucoma,ages 46 to 69 years, were studied. Twenty healthy volunteers (20 eyes) with normal intraocular pressure and with no eye diseases served as controls.
Purpose: To determine whether the s-wave is present in the multifocal electroretinogram (mfERG) and whether it is altered in eyes with primary open-angle glaucoma (POAG).
Methods: A Visual Evoked Response Imaging System was used to record mfERGs from 15 eyes of 15 normal adults, as control eyes, and from 15 eyes of 15 patients with POAG. The stimulus consisted of 37 hexagonal stimulating elements with luminances of 200 cd/m(2) (white), 66.
Purpose: To evaluate changes in the anterior and posterior corneal shape, corneal thickness, and anterior chamber depth (ACD) caused by mydriasis or miosis using scanning-slit corneal topography.
Setting: Department of Ophthalmology, Iwate Medical University School of Medicine, Iwate, Morioka, Japan.
Methods: Twenty-eight eyes of 28 healthy volunteers with refractive errors of -6.
Purpose: To determine how the photopic negative response (PhNR) is affected in central retinal artery occlusion (CRAO).
Design: Observational case series.
Methods: Seven patients with unilateral CRAO were included.
Objective: To determine how the photopic negative response (PhNR) is altered in patients with optic nerve atrophy.
Methods: Ten patients with optic nerve atrophy induced by compression, trauma, or inflammation were examined. There were 6 men and 4 women with a mean age of 52.
Purpose: To investigate how long indocyanine green (ICG) dye remains in the ocular fundus and how the remaining dye interferes with ICG angiographic findings after vitreoretinal surgery assisted by ICG.
Methods: Eight eyes with macular hole, three with epiretinal membrane, and one with an intraocular foreign body were included. Those patients underwent vitrectomy facilitated by an intraocular administration of ICG.
ATP, when leaked from damaged cells, is capable of eliciting responses in neighboring cells. A better understanding of the mechanism of this response is essential for designing therapeutic strategies for disease, there have been only a limited number of studies on the effect of ATP on the human cornea. We examined ATP-induced intracellular Ca2+ ([Ca2+]i) changes in the human corneal epithelia, cultured to near confluence.
View Article and Find Full Text PDFPurpose: To determine the effects of aging on the first and second-order kernels of the multifocal electroretinogram (ERG).
Methods: Multifocal ERGs were recorded from 52 healthy subjects (52 eyes) (0 >or= refractive error >or= -3.0 diopter).
A new wavelet in the multifocal electroretinogram, probably originating from ganglion cells.
Invest Ophthalmol Vis Sci
May 2002
Purpose: To report the properties of a newly detected positive wavelet on the descending limb of P1 of the first-order kernel of the human multifocal electroretinogram (mfERG).
Methods: Twenty eyes of 20 normal individuals, ages 21 to 29 years (mean, 25.6) and nine eyes of 6 patients with optic neuritis ages 5 to 38 years (mean, 17.