Biomedical subjects

Yoshiaki Kitazawa

Publications and source records attributed to Yoshiaki Kitazawa.

23 records · Page 2Linked to original sources

PubMed2002

Properties of perimetric threshold estimates from Full Threshold, SITA Standard, and SITA Fast strategies.

PURPOSE: To investigate the distributions of threshold estimates with the Swedish Interactive Threshold Algorithms (SITA) Standard, SITA Fast, and the Full Threshold algorithm (Humphrey Field Analyzer; Zeiss-Humphrey Instruments, Dublin, CA) and to compare the pointwise test-retest variability of these strategies. METHODS: One eye of 49 patients (mean age, 61.6 years; range, 22-81) with glaucoma (Mean Deviation mean, -7.13 dB; range, +1.8 to -23.9 dB) was examined four times with each of the three strategies. The mean and median SITA Standard and SITA Fast threshold estimates were compared with a "best available" estimate of sensitivity (mean results of three Full Threshold tests). Pointwise 90% retest limits (5th and 95th percentiles of retest thresholds) were derived to assess the reproducibility of individual threshold estimates. RESULTS: The differences between the threshold estimates of the SITA and Full Threshold strategies were largest ( approximately 3 dB) for midrange sensitivities ( approximately 15 dB). The threshold distributions of SITA were considerably different from those of the Full Threshold strategy. The differences remained of similar magnitude when the analysis was repeated on a subset of 20 locations that are examined early during the course of a Full Threshold examination. With sensitivities above 25 dB, both SITA strategies exhibited lower test-retest variability than the Full Threshold strategy. Below 25 dB, the retest intervals of SITA Standard were slightly smaller than those of the Full Threshold strategy, whereas those of SITA Fast were larger. CONCLUSIONS: SITA Standard may be superior to the Full Threshold strategy for monitoring patients with visual field loss. The greater test-retest variability of SITA Fast in areas of low sensitivity is likely to offset the benefit of even shorter test durations with this strategy. The sensitivity differences between the SITA and Full Threshold strategies may relate to factors other than reduced fatigue. They are, however, small in comparison to the test-retest variability.

Adult↗

PubMed2002

[The effect of phosphodiesterase type 3 inhibitor on chorio-retinal blood flow in rabbits eyes].

PURPOSE: To investigate the ocular effect of intravenous administration of a phosphodiesterase type 3 inhibitor (NSP-805) and to compare the effect of NSP-805 with that of a calcium antagonist (nicardipine hydrochloride) on chorio-retinal blood flow in anesthetized albino rabbits. METHODS: Twenty-four female albino rabbits (weighting 2.0-4.0 kg) were anesthetized with intravenous injection. NSP-805(40 micrograms/kg and 100 micrograms/kg) and nicardipine of 40 micrograms/kg were intravenously administrated to the anesthetized rabbits. Intravenously administration of 20% dimethyl sulfoxide (DMSO) was used as a vehicle. Chorio-retinal blood flow was measured with a laser Doppler flowmeter at baseline and every 20 minutes after intravenous administration for 120 minutes. Heart rates and systemic blood pressure were monitored. Baseline measurements were compared with every 10 minutes after intravenous administration. Differences between the drug groups and vehicle group were analyzed. RESULTS: After administration of a low dose of NSP--805 (40 micrograms/kg) and nicardipine (40 micrograms/kg), the chorio-retinal blood flow was significantly increased (p < 0.05). A high dose NSP-805(100 micrograms/kg) reduced systemic blood pressure significantly, but the increase of chorio-retinal blood flow was less than that at the low dose of NSP-805(40 micrograms/kg) and nicardipine (40 micrograms/kg). Chorio-retinal blood flow in the NSP 805(40 micrograms/kg) and nicardipine (40 micrograms/kg) groups was significantly increased over that in the control group (20% DMSO) (p < 0.05). CONCLUSION: The results suggest that the NSP-805 has the potential of increasing chorio-retinal blood flow in rabbit eyes.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMedDate not supplied

Neuroprotective effects of R(-)-1-(benzo[b]thiophen-5-yl)-2- [2-(N,N-diethylamino)ethoxy]ethanol hydrochloride (T-588) against retinal ganglion cell death induced by elevated intraocular pressure in rat.

PURPOSE: We investigated whether T-588 can attenuate retinal ganglion cell (RGC) death induced by elevated intraocular pressure (IOP). METHODS: IOP elevation was induced unilaterally by argon laser irradiation of the rat trabecular meshwork 4 days after an intracameral injection of India ink. We orally administered either the vehicle, or 10, 30, or 100 mg/kg body weight (BW) of T-588 24 hours before the laser application. Five days after the laser application, 1.5 microL of 3% Fast Blue was injected into the superior colliculi bilaterally. Three days after the Fast Blue injection, the eye was enucleated and the retinal whole flatmount was prepared. Labeled ganglion cells were counted by fluorescence microscope with an ultraviolet filter. RESULTS: Laser treatment significantly increased the IOP. The percentages of labeled RGCs in the lasered eyes as compared with the nonlasered contralateral eyes were 78.0 +/- 11.6% in the control group, 78.7 +/- 12.9% in the 10 mg/kg BW group, 79.1 +/- 13.0% in the 30 mg/kg BW group, and 91.0 +/- 9.0% in the 100 mg/kg BW T-588-treated group. The survival rate of RGCs was significantly higher in the 100 mg/kg BW T-588-treated group than in the control group. CONCLUSION: T-588 appears to have a neuroprotective effect on retinal ganglion cells in this ocular hypertensive model.

Administration, Oral↗

PubMedDate not supplied

Influence of topical betaxolol and timolol on visual field in Japanese open-angle glaucoma patients.

PURPOSE: To assess the effects of topical betaxolol and timolol on the visual field in Japanese open-angle glaucoma (OAG) patients. METHODS: This study was a multicenter, 2-year, prospective, randomized and double-masked study. Tests using the Humphrey 30-2 perimeter program were conducted every 6 months and the data of 95 patients were analyzed using regression analysis. Estimated regression coefficients for mean deviation (MD), corrected pattern standard deviation (CPSD), and total deviation (TD) values clustered into 15 sectors were obtained for each treatment group. RESULTS: Estimated slopes (dB/year) for MD and CPSD showed no significant difference from zero in either group. However, in the betaxolol group, estimated slopes (dB/year) for two adjacent sectors in the inferior arcuate area were significantly positive (P =.0135,.0116) while in the timolol group, no significant difference from zero was seen in any of the sectors. IOP changes from baseline in the timolol group were greater than in the betaxolol group, although no statistical significance was seen at any of the examination times. CONCLUSION: MD and CPSD showed no significant change in either group. In the betaxolol group, however, a significant trend in improvement of visual field performance was seen in the inferior arcuate subfield. Timolol reduced IOP more effectively than betaxolol in OAG patients.

Administration, Topical↗

PubMedDate not supplied

Quantification of retinal nerve fiber defects in glaucoma: three-dimensional analysis by Heidelberg retina tomograph.

PURPOSE: To describe a new method of quantifying retinal nerve fiber layer defects (NFLD) in glaucomatous eyes using the Heidelberg Retina Tomograph (HRT). METHODS: Mean tomographic images including the optic disc and peripapillary area were constructed using HRT. An image field of 15 degrees x 15 degrees or 20 degrees x 20 degrees was used for the NFLD analysis. Data on the nerve fiber layer thickness was collected and further analyzed circumferentially across the NFLD at a position 500 microm away from the optic disc margin. We studied 31 patients with early to moderate open-angle glaucoma, ie, with visual field defects appearing earlier than stage 3 of the modified Aulhorn-Greve classification. We determined the width (W), maximum depth (D), and cross-sectional area of the NFLD (A), and we identified correlations between these parameters and the visual field indices from Humphrey Visual Field tests, mean deviation (MD) and corrected pattern standard deviation (CPSD). RESULTS: NFLD parameters could be obtained from 20 of 31 eyes (65%). There was a statistically significant correlation between the D and A parameters, and between these parameters and the maximum depression threshold in the corresponding visual field. No significant correlation was found between the NFLD parameters, the global visual field indices (MD, CPSD) and the mean value of the total deviation (TD) in the corresponding hemifield visual field. CONCLUSIONS: A cross-sectional NFLD image can be obtained using HRT. Among the three NFLD parameters, maximum depth (D), and area under the surface (A) correlated well with the visual field threshold.

Diagnostic Techniques, Ophthalmological↗