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Biomedical subjects

S Harino

Publications and source records attributed to S Harino.

At least 19 recordsLinked to original sources

Indocyanine green and fluorescein hyperfluorescence at the site of occlusion in branch retinal vein occlusion.

BACKGROUND: In patients with branch retinal vein occlusion (BRVO), we investigated the presence of indocyanine green (ICG) and fluorescein hyperfluorescence at the site of occlusion. We also assessed the association of this feature with the clinical outcome of these patients. METHODS: Both indocyanine green (ICG) videoangiography and fluorescein angiography (FAG) were performed in 21 eyes with BRVO of less than 1 month duration. Deterioration of the disease was defined clinically as an increase in retinal hemorrhages or retinal edema. Capillary nonperfusion was quantified with computer image analysis from the FAG pictures. RESULTS: ICG videoangiography showed focal hyperfluorescence along the venous wall at the site of the affected A-V crossing in 9 of the 21 eyes, and FAG showed this feature in 10 eyes. The ICG hyperfluorescence was more prominently and focally detected than the hyperfluorescence on FAG, which was sometimes diffusely seen throughout the whole occluded area. Eight of the nine eyes showing ICG hyperfluorescence had clinical deterioration with an increase in retinal hemorrhage or edema. This deterioration occurred more frequently in eyes with hyperfluorescence and/or late leakage than in ones without these features. The mean nonperfused area was significantly larger in eyes with hyperfluorescence than in eyes without these features. CONCLUSION: The ICG hyperfluorescence at the site of A-V crossing is associated with disease deterioration in patients with fresh BRVO. The ICG hyperfluorescence was more easily detectable than the hyperfluorescence on FAG, although the difference in sensitivity between the two methods is not great.

Adult↗

The effect of nipradilol, an alpha-beta blocker, on retinal blood flow in healthy volunteers.

PURPOSE: To study the effects of topically applied nipradilol, an alpha-beta blocker recently developed in Japan as an ocular hypotensive drug, on retinal blood flow (RBF) in healthy volunteers. METHODS: Seven healthy volunteers (mean age, 33 years) underwent measurement of RBF using a newly developed stabilized laser Doppler velocimetry system. In a double-blind trial, retinal arterial blood flow, intraocular pressure (IOP), and blood pressure (BP) were measured before and after the instillation of nipradilol or saline every hour for 5 hours. RESULTS: Retinal arterial blood flow and the diameter of the retinal artery significantly (p< 0.05) increased at 4 hours after instillation in nipradilol-treated eyes. Retinal blood velocity did not change significantly. Nipradilol evoked a significant (p< 0.05) bilateral decrease in IOP. Mean BP decreased significantly (p< 0.05) 3 hours after instillation. Ocular perfusion pressure (OPP), calculated from the mean BP and IOP, did not change significantly during the study. CONCLUSION: Topical nipradilol significantly increased retinal arterial blood flow in healthy volunteers, not through a secondary effect dependent on a change in OPP, but likely through the vasodilatory action of the drug.

Adrenergic alpha-Antagonists↗

Liposomal prostaglandin E1 enhances optic nerve head blood flow in cats.

We investigated the effects of intravenous administration of prostaglandin E1 (PGE1) and lipo-prostaglandin E1 (lipo-PGE1), on optic nerve head blood flow (ONHBF) using ten anesthetized cats. Changes in relative ONHBF were noninvasively and continuously measured with fundus camera-based laser Doppler flowmetry. The blood pressure (BP) decreased significantly by 6 +/- 5 (mean +/- SD)% and 8 +/- 4%, respectively, after PGE1 (30, 100 ng/kg/min) administration, but at either of these concentrations there were no significant changes in ONHBF. On the other hand, with lipo-PGE1 (10 ng/kg/min), the BP remained unchanged, but ONHBF increased significantly by 61 +/- 49%. A larger dose of lipo-PGE1 (30 ng/kg/min) had opposite effects because the BP decreased significantly by 14 +/- 4% after administration, and the ONHBF remained unchanged (i.e., 67 +/- 102%). In all cases, there were no changes in IOP. With 10 ng lipo-PGE1, the large increase in ONHBF can be accounted for by vasodilation since perfusion pressure was unchanged. The inability of 30 ng lipo-PGE1 to affect ONHBF could be ascribed to the decrease in BP resulting in decreased ocular circulation. These results suggest that, in humans, lipo-PGE1 may also increase ONHBF provided that it is used at doses that do not produce large decreases in BP.

Alprostadil↗

A high incidence of Staphylococcus aureus colonization in the external eyes of patients with atopic dermatitis.

OBJECTIVE: To determine the frequency distribution of bacteria on the external surface of eyes of patients with atopic dermatitis (AD) and to investigate the relationship between the frequency of bacterial colonization and the grade of atopy or ocular diseases associated with AD. DESIGN: Comparative cross-sectional study. PARTICIPANTS: Thirty-six AD patients (mean age, 24.5 years) and 16 nonatopic, age-matched control participants (mean age, 25.5 years). INTERVENTION: The eyelid margins and conjunctival sacs were scraped with sterile swabs. These samples were inoculated into aerobic and anaerobic culture media. MAIN OUTCOME MEASURES: The frequency distribution of bacteria isolated from the eyelid margins and conjunctival sacs. RESULTS: Bacteria isolated from AD patients were: Staphylococcus aureus in 21 of 36 patients (including methicillin-resistant Staphylococcus aureus in two patients); Staphylococcus epidermidis in two patients (including methicillin-resistant Staphylococcus epidermidis in one patient); other coagulase-negative Staphylococcus in six patients;alpha-streptococcus in three patients; Corynebacterium species in three patients; Neisseria species in two patients; and Propionibacterium acnes in one patient. From the nonatopic control participants, we isolated S. aureus in one patient, S. epidermidis in two patients and alpha-streptococcus in one patient. S. aureus was isolated from 67% of the AD patients, and any type of bacteria was isolated from 86% of the patients. These rates were significantly higher than those of nonatopic control participants (6% S. aureus and 25% any bacteria). There was no significant relationship between the frequency distribution of bacteria and the grade of atopy or associated ocular diseases. CONCLUSIONS: High rates of bacterial colonization, especially S. aureus, were found in the conjunctival sacs and eyelid margins of AD patients. In case management of AD patients, this unique distribution of bacteria must be carefully considered.

Adolescent↗

Real time fixation point monitoring system for photocoagulation of juxtafoveal neovascularisation.

BACKGROUND/AIMS: A new real time monitoring system has been developed to locate the fixation point during juxtafoveal laser photocoagulation. METHOD: The red diode laser beam is combined coaxially with the illumination beam to image a cross in the focal plane of the slit lamp, which allows projection of a red cross onto the patient's fundus. 27 patients with juxtafoveal choroidal neovascularisation were treated by photocoagulation using this system. RESULTS: 13 (48%) patients whose visual acuity ranged from 20/200 to 20/40 answered that it was easier to keep the focus on the cross target image than on the aiming beam. The patient maintained stable fixation throughout the treatment. The laser treatment was completed without foveal damage near the fixation point in all patients. CONCLUSION: The real time fixation monitoring system should allow surgeons to treat juxtafoveal lesions with laser photocoagulation more safely and accurately.

Choroidal Neovascularization↗

Role of nitric oxide in mediating retinal blood flow regulation in cats.

The role of nitric oxide (NO) was evaluated in mediating control of retinal blood flow in the anesthetized cat. This was done under resting conditions and as a function of decreases in perfusion pressure. The retinal blood flow was calculated by measuring blood velocity with laser Doppler velocimetry (LDV) and retinal blood vessel diameter with image analysis. Graded decreases in perfusion pressure were obtained by increasing intraocular pressure (IOP). Following intravenous administration of 30 mg/kg NG-nitro-L-arginine methyl ester (L-NAME), an NO synthase inhibitor, the arterial blood pressure increased under resting conditions by 34+/-3% (n = 7), the blood vessel diameter decreased by 18+/-2%, and retinal blood flow significantly declined by 27+/-6% (n = 6). Irrespective of the presence or absence of L-NAME (30 mg/kg), stepwise reductions in perfusion pressure that reached a level that was 35% of the baseline value had no significant effect on retinal blood flow. These results suggest that, under resting conditions, retinal blood flow decreases in response to a putative fall in NO levels. However, NO does not appear to be involved in mediating the autoregulatory response to a decrease in perfusion pressure.

Animals↗

Extraction of fluorescent dot traces from a scanning laser ophthalmoscope image sequence by spatio-temporal image analysis: Gabor filter and radon transform filtering.

The scanning laser ophthalmoscope (SLO) allows the tracking of fluorescent dot motion, thereby enabling the flow velocities in perimacular capillaries to be directly measured. These can serve as an important index of local retinal soundness or reflect the whole body circulation status in disorders such as diabetes. Although it is possible to perceive moving fluorescent dots with the human eye, they are so faint and unstable that it is difficult to detect them by conventional digital still-image processing methods. To solve this problem, we generated spatio-temporal images of the fluorescent dots in a capillary and applied Gabor filters tuned to the direction of the traces in order to detect them. Finally, by discriminating and integrating the output using two levels of threshold, we were able to extract their traces. Because the medium-size Gabor filter requires a considerable amount of time for two-dimensional convolution calculation, we prove that there is a certain equivalence between the Gabor filter, the radon transform, and the Hough transform. In the light of this, we propose a form of radon transform filtering that includes a radon transform Gabor filter as a very long Gabor filter. This allows a whole trace to be detected in a single step with a one-dimensional convolution, thereby shortening the processing time. In an experiment, 60% of the traces could be detected without error, which is sufficient to allow the mean flow velocity in a capillary to be measured.

Filtration↗

Effects of intravenous cilostazol on optic nerve head and choroidal blood flow in anesthetized cats.

Cilostazol is one of a number of anti-platelet agents used for the treatment of thrombotic disorders, such as chronic arterial obstruction, and is a vasodilator as well. In the present study, cilostazol was intravenously administered to seven anesthetized cats, and the optic nerve head (ONH) and choroidal blood flows were continuously monitored in a noninvasive method using laser Doppler flowmetry. The systemic blood pressure dropped significantly by 4+/-4% (p<0.05) with cilostazol 0.03 microg/kg/min, although there were no significant changes in ONH and choroidal blood flows. When the drug was given at 0.1 microg/kg/min, ONH blood flow remained significantly higher than the baseline, 54+/-37% (p<0.05) at maximum, immediately after the start of administration. Soon after the start of the infusion, a significant decrease, 17+/-10% (p<0.05) at maximum, in choroidal blood flow occurred, but this was followed by a significant increase, 35+/-27% (p<0.05) at maximum. At that time, the systemic blood pressure dropped significantly by 14+/-6% (p<0.05). These findings indicate that an intravenous administration of cilostazol increases both ONH and choroidal blood flows, suggesting the potential usefulness of cilostazol for both prophylactic and therapeutic management of ophthalmic circulatory disorders.

Animals↗

Scanning laser ophthalmoscope microperimetric assessment in patients with successful laser treatment for juxtafoveal choroidal neovascularization.

PURPOSE: To evaluate fixation stability and changes in retinal function in patients with laser scar expansion after successful macular photocoagulation for juxtafoveal choroidal neovascularization (CNV). METHODS: A consecutive series of 35 patients was examined in this prospective study. Only patients who had been successfully treated with laser photocoagulation for juxtafoveal CNV and who could be followed over a period of at least 6 months were enrolled. Fixation stability and localized light sensitivity were examined by microperimetry using a scanning laser ophthalmoscope. Visual acuity was measured 2 weeks and 3 and 6 months after the laser treatment. The correlation between changes in the logarithm of the minimum angle of resolution (LogMAR) visual acuity and the distance between fixation and the center of the fovea was evaluated. RESULTS: Of 22 eyes of 20 patients that underwent data analysis, laser scar expansion was observed in 16 (72.7%). Ten (62.5%) of the 16 eyes had relative scotomas corresponding to the expanded laser scars. Mean laser scar expansion ratio was 28.7% in the ARMD group and 109.2% in the myopia group, a statistically significant difference (P < 0.01). The change in LogMAR visual acuity was significantly correlated with the distance of fixation locus from the center of the fovea (r = 0.76). CONCLUSIONS: Laser scars produced by photocoagulation for juxtafoveal CNV may expand and extend into the fovea, causing secondary retinal dysfunction. Scanning laser ophthalmoscopic assessment may be useful in evaluating fixation stability and subclinical changes in retinal function surrounding the laser scars before visual disturbance appears.

Aged↗

[Evaluation of scanning laser Doppler flowmetry in anesthetized cats].

The aim of this work was to evaluate the reliability of scanning laser Doppler flowmetry (SLDF) developed by Michelson (Heidelberg retina flowmeter) as compared to fundus camera based laser Doppler flowmetry (FLDF). Blood flow was measured on several occasions by SLDF in the optic nerve head (ONH) and in retinal capillaries of the intervascular area (IV A) in four immobilized anesthetized cats. The circulation was stimulated with pure oxygen breathing, and intravenous infusion of noradrenalin or papaverine. Blood flow was also monitored during euthanasia. The two techniques were compared in repeated successful experiments. In the ONH and IV A, mean values of blood flow were 20-1600 (arbitrary units, AU), and 400-1700 AU respectively. The mean coefficient of variance was 9.1% in the ONH and 8.0% in the IV A in five consecutive measurements. The relative change in IV A blood flow between SLDF and FLDF during noradrenalin infusion were similar over time, although the values of the changes were not significantly correlated (n = 15 r = 0. 489 p = 0.064). Papaverine infusion showed various responses in the ONH except one point where FLDF showed an increase in blood flow. During euthanasia, the SLDF revealed an increase in ONH blood flow temporally in some animals, but not in IV A. A Value of 100-200 AU for both ONH and IV A remained even after euthanasia. The FLDF, however, showed a decrease in ONH blood flow with systemic blood pressure. Measurement of IV A blood flow appears more reliable than that of ONH blood flow. The characteristics of SLDF should be considered when we interpret the blood flow value.

Animals↗

Friedreich-like ataxia with retinitis pigmentosa caused by the His101Gln mutation of the alpha-tocopherol transfer protein gene.

The alpha-tocopherol transfer protein (alpha-TTP) is a cytosolic liver protein that is presumed to function in the intracellular transport of alpha-tocopherol, the most biologically active form of vitamin E. We studied 4 unrelated patients with autosomal recessive Friedreich-like ataxia who had isolated vitamin E deficiency. A point mutation was identified in all of them at position 101 of the gene for alpha-TTP, where histidine (CAT) was replaced with glutamine (CAG). Three of the 4 patients developed retinitis pigmentosa subsequent to the onset of ataxia. Neurological symptoms included ataxia, dysarthria, hyporeflexia, and decreased proprioceptive and vibratory sensations. Electrophysiological and pathological examinations showed that the cardinal sites affected were the central axons of dorsal root ganglion cells and the retina, with minor involvement of the peripheral sensory nerve, optic nerve, and pyramidal tract. The vitamin E tolerance test performed showed that the absorption of vitamin E was normal but that its decrease from the serum was accelerated. Oral administration of vitamin E appeared to halt the progression of visual and neurological symptoms. We propose a new treatable syndrome of Friedreich-like ataxia and retinitis pigmentosa caused by a defect in the alpha-TTP gene.

Aged↗

Comparative study of intraocular lens implantation through 3.0 mm temporal clear corneal and superior scleral tunnel self-sealing incisions.

PURPOSE: To compare the clinical outcome of phacoemulsification and foldable silicone intraocular lens (IOL) implantation through a 3.0 mm temporal clear corneal incision and 3.0 mm superior scleral tunnel incision. SETTING: Department of Ophthalmology, Yodogawa Christian Hospital, Osaka, Japan. METHODS: Eighty cataractous eyes of 78 patients with pre-existing against-the-rule (ATR) astigmatism were recruited for this prospective, randomized study. The patients were assigned to one of the two groups. Data on uncorrected and corrected visual acuities, keratometry, flare intensity measurement, and central cornea endothelial cell count were evaluated preoperatively and at 2 days, 1 week, and 1 and 3 months postoperatively. RESULTS: Although the pre-existing keratometric cylinder decreased in the temporal clear corneal incision group and increased in the superior scleral tunnel incision group, the amount of cylinder shift was not significantly different. Mean scalar shift of keratometric cylinder in the corneal incision group was 1.19 diopters (D) at 2 days postoperatively, 0.86 D at 1 week, and 0.56 D at 3 months and in the scleral incision group, 1.09 D at 2 days, 0.76 D at 1 week, and 0.65 D at 3 months. Eighty percent of the eyes in each group achieved an uncorrected visual acuity of 20/40 or better from the second day postoperatively. No statistically significant difference in visual rehabilitation or other parameters was noted between the groups throughout the study. Complications including corneal endothelial cell loss and wound incompetence requiring suturing were observed in the temporal clear corneal incision group. CONCLUSIONS: Both incisions offered satisfactory clinical results, but the superior scleral tunnel incision resulted in fewer complications. Minimal corneal keratometric change induced by a 3.0 mm incision was not related to uncorrected visual rehabilitation.

Aged↗

[Optic nerve head and choroidal circulation measured by laser Doppler flowmetry in response to intravenous administration of noradrenaline].

We investigated the change of optic nerve head blood flow (ONHBF) and choroidal blood flow (CBF) in response to noradrenaline (NA) intravenously administered in anesthetized cats. NA (0.03, 0.1, 0.3 micrograms/kg/min) was injected 5 minutes continuously via the femoral vein. The relative blood flow and systemic blood pressure were continuously measured before and after NA administration with fundus camera-based laser Doppler flowmetry. Systemic blood pressure increased by 6%, 42% and 48% according to the dose. The changes in ONHBF after NA administration were -1.4 +/- 3.5% (mean +/- standard deviation) with 0.03 micrograms/kg/min, 2.4 +/- 6.9% with 0.1 micrograms/kg/min, -2.2 +/- 4.4% with 0.3 micrograms/kg/min, respectively. It did not change significantly despite doses of NA. CBF did not change significantly with 0.03 micrograms/kg/min. CBF increased significantly by 62.7 +/- 65.4% with 0.1 micrograms/kg/min, and 80.4 +/- 73.1% with 0.3 micrograms/kg/min. These results suggest that ONHBF is autoregulated despite the change of perfusion pressure by NA administration. This response is different from that of CBF.

Animals↗

[Treatment of age-related subfoveal choroidal neovascularization by low-dose external radiation: a preliminary study].

We applied low dose external beam radiation (6 MV) to 17 eyes of 17 patients (Mean age 70.9 years, range 58 approximately 85) who had subfoveal choroidal neovascularization associated with age-related macular degeneration. None of the cases were suitable for photocoagulation according to the Macular Photocoagulation Study protocol, and no feeding vessels underlying choroidal neovascular membrane could be detected. Corrected visual acuity ranged from 0.02 to 0.6 before treatment. The patients were divided into two groups. One group of 11 eyes was treated with 10 Gy and the other group of 6 eyes with 21 Gy. Mean follow up period was 347 +/- 89 (mean +/- standard deviation) days in the 10 Gy group and 312 +/- 100 days in the 21 Gy group. We evaluated the outcome as "effective' if no progression in neovascular membrane was found by ophthalmoscopic and angiographic examination. Only 3 eyes (21%) of patients in the 10 Gy group and 2 eyes (33%) in 21 Gy group showed any effect. Although the rate of progression in choroidal neovascular membrane was significantly smaller in the 10 and 21 Gy group than in the controls, the corrected visual acuity in the treated group was not improved over that of the controls. No serious complications were seen. Only one case showed a stabilized neovascular membrane in the control group of 7 patients. Although the present results seem to be worse than those in previous reports, the efficacy of this treatment still needs to be evaluated because no beneficial strategies in the treatment of subfoveal neovascularization have been established.

Aged↗

[The effect of hyperbaric oxygen on ophthalmic artery blood velocity in patients with diabetic neuropathy].

We investigated changes in the blood velocity of the ophthalmic artery to observe its relationship to the complication of diabetes mellitus before and after hyperbaric oxygen therapy (HBO). Color Doppler imaging (Toshiba, SSA-260A) was used. In this study, there were 7 diabetic neuropathy patients, 3 diabetes patients without neuropathy, and 7 normal subjects for control. These patients were examined before and after HBO. The patients were made to breathe 100% oxygen at 2.0 atmosphere absolute (ATA) for one hour. HBO is sometimes used for treatment of diabetic neuropathy. HBO produced an average decrease in blood velocity of 15.0 +/- 9.0 (mean +/- standard deviation) % in normal subjects, 10.7 +/- 8.6% in diabetes patients without neuropathy, and returned to the baseline level 4 hours after the conclusion of HBO. On the other hand, the blood velocity increased by about 20.6 +/- 9.5% in diabetic neuropathy patients regardless the degree of severity of diabetic retinopathy. These results suggest that the increase in the blood velocity of the ophthalmic artery after HBO in diabetic neuropathy patients could be attributed to an imbalance in autonomic nervous function.

Blood Flow Velocity↗

Indocyanine green angiographic findings in Vogt-Koyanagi-Harada disease.

PURPOSE: To report the indocyanine green angiographic findings associated with Vogt-Koyanagi-Harada disease and compare them with fluorescein angiographic findings and monochromatic scanning laser images. METHODS: In a prospective study, indocyanine green angiography, by scanning laser ophthalmoscopy or infrared fundus photography, was performed in ten consecutive patients (20 eyes) with Vogt-Koyanagi-Harada disease during the acute stage before and recovery stage after corticosteroid treatment. Findings were compared with fluorescein angiographic features and monochromatic scanning laser imaging. RESULTS: During the acute stage of the disease, indocyanine green angiography disclosed a dark background in the early phase and multiple, non-uniform hypofluorescent lesions in the midphases. Lesions were more numerous and extensive than areas either of serous retinal detachment on monochromatic scanning laser imaging or of punctate hyperfluorescence on fluorescein angiography. During the recovery stage, the abnormal dark background on indocyanine green angiography at initial examination resolved, with choroidal vessels visible in all cases, but nonuniform hypofluorescent lesions persisted in most eyes. Fluorescein angiography disclosed hypofluorescent patchy areas, and confocal infrared laser imaging showed some bright reflective lesions in three patients with especially severe clinical symptoms. On final examination after an average of 17.7 months, both angiographies still disclosed abnormal findings in these three patients. CONCLUSIONS: Indocyanine green angiographic findings suggest that choroidal inflammation may cause a transient choroidal circulatory disturbance during the acute stage of Vogt-Koyanagi-Harada disease. In more severe cases, this dysfunction may secondarily damage the retinal pigment epithelium.

Acute Disease↗

Effects of endothelin-1 on optic nerve head blood flow in cats.

We determined the effects of endothelin-1 on optic nerve head (ONH) blood flow in anesthetized cats. Endothelin-1 (50-2500 pmol) injected into the vitreous produced a dose-related and sustained decrease (22 +/- 6% by 500 pmol and 36 +/- 11% by 2500 pmol) in the ONH blood flow. Blood pressure (BP) and heart rate (HR) remained, however, unchanged. In contrast, intravenous (i.v.) injected endothelin-1 (0.004-0.4 nmol kg-1) produced a dose-related and short-lasting increase in the ONH blood flow; its maximum increase by 0.4 nmol kg-1 was 135 +/- 34%. Endothelin-1, at 0.4 nmol kg-1, i.v., produced a transient decrease followed by a more sustained increase in BP, but had no remarkable effect on HR. The increase in ONH blood flow by i.v. injection of endothelin-1 was abolished by N(G)-nitro-L-arginine methyl ester (L-NAME, 5 mg kg-1 min-1, i.v.). The suppression of blood flow by L-NAME was reversed by the addition of L-arginine (50 mg kg-1 min-1). Pressor responses to endothelin-1 (0.4 nmol kg-1, i.v.) were augmented in the presence of L-NAME, but reversed in combination with L-arginine. These findings suggest that i.v. injection of endothelin-1 causes NO release from endothelial cells which increases ONH blood flow, whereas intravitreal injection of endothelin-1 decreases ONH blood flow by its vasoconstrictive effect. Different populations of ET receptors on vascular smooth muscles or endothelial cells would reflect the opposing effects of endothelin-1.

Animals↗