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Biomedical subjects

M Araie

Publications and source records attributed to M Araie.

At least 91 records · Page 5Linked to original sources
PubMed1997

Effect of topical beta-blockers on tissue blood flow in the human optic nerve head.

PURPOSE: To study the effect of topical 0.5% timolol and 2% carteolol on tissue blood flow in the human optic nerve head (ONH). METHODS: Using a laser speckle tissue blood flow analyzer, normalized blur (NB), a quantitative index of tissue blood velocity, was measured every 0.125 s in the temporal site of the ONH free of visible surface vessels and averaged over 3 cardiac pulses (NBONH). To serve as a baseline, NBONH and intraocular pressure (IOP) in both eyes, blood pressure (BP) and pulse rate (PR) were recorded in healthy volunteers before, 1.5, 3 and 4.5 hrs after a 30L instillation of the vehicle of timolol or carteolol. From the following day and twice daily for 3 weeks, 30L of either 0.5% timolol or 2% carteolol was instilled into one eye and the respective vehicle into the fellow eye in a masked manner. NBONH, IOP, BP and PR were again recorded on the 21st and last experiment day. IOP was also recorded on the 7th and 14th days. Carteolol concentration in the plasma was also recorded after instillation of carteolol on the 21st day. RESULTS: During the baseline experiments, all the parameters recorded showed no significant change. After topical timolol, IOP was significantly reduced bilaterally with more reduction in the timolol-treated eye. Bilateral NBONH, BP and PR showed little change on the 21st day. After topical carteolol, IOP was significantly reduced bilaterally with more reduction in the carteolol-treated eyes on the 21st day. NBONH in the carteolol- and vehicle-treated eyes was significantly higher on the 21st day than recorded in the same eye in the baseline experiment (P = 0.013 and 0.047), while BP and PR showed little change. The maximum carteolol concentration in plasma at 3 hrs on the 21st day averaged 1294 pg/ml. CONCLUSIONS: Results indicated that 3-week twice daily topical timolol treatment had no deleterious effect on the ONH tissue blood flow in the human eye, and that 3-week twice daily topical carteolol treatment may increase the tissue blood flow in the human ONH.

Administration, Topical↗
PubMed1997

Intraocular pressure and central visual field of normal tension glaucoma.

AIM: To study whether damage in the central 30 degrees field of normal tension glaucoma (NTG) is relatively heterogeneous or homogeneous with respect to intraocular pressure (IOP) related damage. METHODS: Using the results of Humphrey perimeter examinations, the central 30 degrees field was divided into four subfields; superior and inferior hemifields excluding the caecocentral field (30-2 program) and superior and inferior 10 degrees hemifields (10-2 program). In 103 NTG cases, the intraindividual bilateral difference in the mean of total deviations (mean TD) in the four subfields was analysed by multiple linear regression to correct the effects of factors other than IOP. Explanatory variables were the intraindividual bilateral difference in the mean of clinic IOP (IOPmean), that in the ratio of area of peripapillary atrophy corresponding to each subfield to disc area, and that in myopic refraction. RESULTS: The intraindividual bilateral difference in the mean TD was significantly and negatively correlated with that in IOPmean in three of the above four subfields (p < 0.005) and correlation tended to be negative (p = 0.07) in the superior 10 degrees hemifield. CONCLUSIONS: Diffuse IOP related damage was suggested in the central 30 degrees field of NTG; greater extent of the damage in the above four subfields was correlated with higher mean IOP. The present findings may have clinical implications.

Glaucoma, Open-Angle↗
PubMed1997

Intraocular irrigating solutions and barrier function of retinal pigment epithelium.

AIM: To study the effect of intraocular irrigating solutions on the barrier property of the retinal pigment epithelium (RPE). METHODS: The isolated rabbit RPE-choroid mounted on Ussing-type chambers under short circuit conditions was used. According to a previous study, the inward (from the choroid to the vitreous side) permeability of the tissue to carboxyfluorescein was adopted as a quantitative index of the barrier function of the RPE cells. RESULTS: Of the three solutions tested, Krebs-Ringer solution, a commercially available glucose glutathione bicarbonate solution (BSS plus), and glucose citrate-acetate bicarbonate solution (Opeguard), BSS plus gave a significantly lower permeability (1.1 x 10(-6) cm/s on average) than Krebs-Ringer solution or Opeguard (1.9 or 1.8 x 10(-6) cm/s on average, respectively) (unpaired t test with Bonferroni's correction, p < 0.05). Since the major chemical difference between BSS plus and the other two solutions is the incorporation of oxidised glutathione (GSSG), the effects of GSSG were studied using solutions having an identical composition to BSS plus, but with various concentrations of GSSG. The solution containing 0.3 mM GSSG gave significantly lower permeability than that without GSSG (1.1 x 10(-6) cm/s v 2.0 x 10(-6) cm/s) (unpaired t test with Bonferroni's correction, p < 0.05). CONCLUSION: It was suggested that BSS plus is less harmful to the barrier function of the RPE cells and that GSSG has a beneficial effect on its maintenance.

Animals↗
PubMed1997

[Effect of non-surgical ocular hypotensive therapy in normal-tension glaucoma].

We investigated the effects of the topical ocular hypotensives with or without half circumference argon laser trabeculoplasty (ALT) on intraocular pressure (IOP) of normal-tension glaucoma (NTG) eyes. Seventy-two NTG patients whose pretreatment mean IOP was > or = 15 mmHg at least in one eye were included and one randomly chosen eye from one patient were used for analysis. They were followed for at least 15 months after commencement of the therapy. The mean pretreatment IOP averaged 17.2 +/- 1.6 mmHg (mean +/- standard deviation, n = 72). All eyes were first treated with topical 2% carteolol. In eyes where IOP reduction was considered unsatisfactory, topical 1% pilocarpine or 0.04% dipivefrine was added. In eyes where IOP reduction was still unsatisfactory even with the two medications, half circumference ALT was performed. Mean IOP reduction was 1.5 mmHg in the eyes treated with topical medications alone and 2.5 mmHg in those treated by topical medications plus ALT. The mean outflow pressure reduction was 16 and 26%, respectively. In 40% of the all eyes, satisfactory IOP reduction was obtained by topical medications with or without additional ALT.

Carteolol↗
PubMed1997

[Measurements of blood flow velocity in human retinal veins using laser speckle flowgraphy system].

We measured the blood flow velocity in human retinal veins using a laser speckle flowgraphy system. This system consists of a fundus camera, a diode laser, an image sensor and a personal computer system. The fundus is illuminated with a diode laser through a fundus camera and the laser speckle pattern is imaged onto the area sensor. From the time change of contrast of speckle pattern, normalized blur (NB) value, a quantitative index of tissue blood velocity, was calculated by means of a logistic board, and two-dimensional distribution of NB in the measurement field was displayed in a color display. In the in vitro experiment, the NB obtained from the blood flow in a glass capillary tube was correlated with the diameter of the tube, background NB value and the blood flow rate actually measured. In the in vivo experiment, the blood velocity in human retinal veins of approximately 50 microns in diameter was estimated in 16 normal eyes using nomograms based on the results of the in vitro experiment. Velocity averaged 11.1 +/- 0.6 mm/ sec (mean +/- standard deviation, n = 16) in retinal veins of 53 +/- 6 microns in diameter and the reproducibility index of the in vivo measurements was 2.5 +/- 0.9%.

Adult↗
PubMed1997

Risk factors for unsatisfactory intraocular pressure control in combined trabeculectomy and cataract surgery.

BACKGROUND AND OBJECTIVE: Trabeculectomy combined with posterior chamber intraocular lens (PC IOL) insertion is often chosen for the treatment of glaucoma combined with cataract. In this study, the clinical prognostic indicators for late intraocular pressure (IOP) control in combined procedures were investigated. PATIENTS AND METHODS: The clinical records of 60 eyes that underwent trabeculectomy combined with PC IOL implantation were retrospectively analyzed using the Cox proportional hazards model. All of the patients received postoperative 5-fluorouracil injections. RESULTS: Extracapsular cataract extraction (ECCE) was found to be a statistically significant risk factor for unsatisfactory late IOP control (hazard ratio 2.54; P < .01) and for unsatisfactory filtering bleb appearance (hazard ratio 5; P < .001). The frequency of fibrin formation and the incidence of a transient IOP spike (> or = 25 mm Hg) were significantly lower in the phacoemulsification and aspiration (PEA) group than in the ECCE group. In the PEA group, the probability of IOP control (< or = 15 mm Hg) without medication was 54%, and the probability of persistent filtering bleb appearance was 80% at 18 months. CONCLUSION: The PEA technique, not ECCE, should be employed in combined trabeculectomy and PC IOL implantation.

Aged↗
PubMed1996

A comparison of latanoprost and timolol in primary open-angle glaucoma and ocular hypertension. A 12-week study.

OBJECTIVE: To evaluate the intraocular pressure (IOP)-reducing effect and the side effects of latanoprost (PhXA41), a new phenyl-substituted prostaglandin F2 alpha-isopropyl ester analogue, in patients with elevated IOP, using timolol maleate as the reference drug. METHODS: A total of 184 patients with primary open-angle glaucoma or ocular hypertension at 35 medical centers participated in this randomized double-masked study. The patients were randomized to receive either 0.005% latanoprost once daily or 0.5% timolol maleate twice daily, for a period of 12 weeks. Intraocular pressure was measured 24 hours after the administration of timolol, at 2, 4, 8, and 12 weeks of treatment. RESULTS: Latanoprost reduced IOP at the end of 12 weeks by 6.2 +/- 2.7 mm Hg (mean +/- SD) (26.8%), while timolol reduced IOP by 4.4 +/- 2.3 mm Hg (19.9%). At all visits latanoprost reduced IOP significantly more than timolol did. The main ocular side effects observed in both groups were conjunctival hyperemia and smarting. The main systemic side effect was a reduced pulse rate, which occurred in patients treated with timolol. CONCLUSIONS: The results of this study demonstrated that 0.005% latanoprost taken once daily is well tolerated and more effective in reducing IOP than 0.5% timolol taken twice daily. Thus, latanoprost may become an important choice for the medical treatment of glaucoma.

Adrenergic beta-Antagonists↗
PubMed1996

Movement of carboxyfluorescein across retinal pigment epithelium-choroid.

The movement of carboxyfluorescein (CF) across the isolated retinal pigment epithelium (RPE)-choroid of the albino rabbit was studied using an Ussing chamber under short-circuit conditions with CF concentrations ranging from 15 to 300 microM. The inward (from the choroid to vitreous side) permeability of the tissue to CF showed no significant change over the concentration range tested, averaging 2.2 x 10(-6) cm sec-1. Neither ouabain (1.0 microM), low external sodium concentration nor probenecid (100 microM) had significant effect on the inward movement of CF. The outward (from the vitreous to the choroid side) permeability of the tissue to CF gradually decreased as the concentration increased (ANOVA, P < 0.01: Scheffe's test, P < 0.05), averaging 3.7 x 10(-6) cm sec-1 at 75 microM. Further, it was always significantly greater than the inward permeability at the corresponding concentration (unpaired t-test, P < 0.05-0.01). The outward movement of CF was significantly inhibited by 2,4-dinitrophenol (10 microM), ouabain (1.0 microM), probenecid (100 microM), iodipamide (5.0 mM), hippurate (30 mM) or low external sodium concentration (25 mM). The net outward movement of CF became saturated as concentration was increased and a Lineweaver-Burk plot gave an apparent Km of 237 microM and Vmax of 1.8 nmol hr-1 cm-2. The results indicated that part of the outward movement of CF across the RPE-choroid depends on carrier mediated active transport, but to a much lesser extent than that of fluorescein. The inward movement of CF was thought to occur almost exclusively by passive diffusion through the paracellular spaces.

2,4-Dinitrophenol↗
PubMed1996

Time change of nicardipine effect on choroidal circulation in rabbit eyes.

PURPOSE: To investigate the time course of effects of intravenous administration of a calcium antagonist, nicardipine, on the choroidal circulation of rabbit eyes using a laser speckle tissue circulation analyzer. METHOD: The rabbit fundus was illuminated by a diode laser spot and its image speckle was detected by an image sensor. The difference between the average of the speckle intensity (Imean) and the speckle intensity for successive scannings was calculated, and the ratio of Imean to this difference was defined as normalized blur (NB); a quantitative index of tissue blood velocity. The average NB over the field measured (0.620.62 mm in the choroid) was calculated to give Nb(av). Under general anesthesia, 0.4 ml/kg of 0.01% nicardipine hydrochloride dissolved in physiological saline was injected intravenously in a group of albino rabbits (control group) for measurement in the choroid (nicardipine groups). To serve as control, 0.4 ml/kg of physiological saline was injected in other groups of albino rabbits (control groups). Nb(av) was recorded at 1-min intervals for the first 5 min and at 5-min intervals for the next 85 min. During the experiment mean femoral arterial blood pressure (FABPm), pulse rate (PR), arterial blood pH, Pco2 and Po2 body temperature (BT) and intraocular pressure (IOP) were also monitored. Before and 45 min after nicardipine administration, the choroidal blood flow measurement using the microsphere technique and the Nb(av) measurement were carried out in the same eye in another group of rabbits. RESULTS: Only the rabbits which did not show any significant change in the PR, pH, Pco2, Po2 and BT during the experiment were accepted. FABPm in the nicardipine group dropped to the minimum at 1 min postadministration and this level remained significantly lower than that in the control group up to 15 min post-injection, while te 10P did not show any significant change. The Nb(av) in the nicardipine group showed a significant increase after the FABPm return to the baseline, which was maintained throughout the experiment. The averaged increase between 30 and 90 minutes after administration was 27 +/- 1% (mean +/- S.E.M., n = 10). Relative increase in choroidal blood flow determined by the microsphere technique showed a good correlation (r = 0.90, P < 0.001, n = 12) with those determined by Nb(av) after nicardipine administration. CONCLUSIONS: The present result indicates that the time course of drug effects on the choroidal circulation can be noninvasively and sensitively followed by Nb(av) measurements. Further, it was shown that nicardipine may have considerable potential for the treatment of ocular diseases associated with insufficient choroidal blood flow and that nicardipine's effects here observed deserve to be further studied in humans.

Animals↗
PubMed1996

[Effect of topical adrenergic agents on tissue circulation in human optic nerve head evaluated with a laser speckle microcirculation analyser].

The effects of a single instillation of 2% carteolol or 0.1% dipivefrine on the tissue circulation in the human optic nerve head (ONH) was studied using a laser speckle tissue circulation analyser in 12 healthy volunteers. In the first experiment, normalized blur (NB), a quantitative index of peripheral blood velocity, was measured every 0.125 sec in an area located in the temporal site of ONH free of visible surface vessels and averaged over 5 pulses (mean NB) in both eyes before, 1.5, 3, and 4.5 hours after a 30 microliters instillation of placebo to serve as a control. Intraocular pressure (IOP), blood pressure (BP), and pulse rate (PR) were also measured. In the second experiment, a 30 microliters drop of 2% carteolol (n = 6) or 0.1% dipivefrine (n = 7) was instilled in one randomly chosen eye and the placebo for each drug in the other eye, and the above parameters were measured according to the same time schedule as in the first experiment in a double masked manner. After topical carteolol, carteolol concentration in the plasma (CC) was also measured. In the control experiments, none of the parameters showed any significant change. After topical carteolol, the IOP was significantly lower between 1.5 and 4.5 hrs in the carteolol-treated eyes and at 1.5 and 4.5 hrs in the fellow eyes as compared with that obtained in the control experiment. The mean NB was significantly higher at 3 hrs (23.1%) in carteolol-treated eyes, and at 3 hrs (17.2%) in the fellow eyes, as compared with that obtained in the control experiment (p < 0.05). BP and PR showed little change. The maximum CC at 3 hrs averaged 522 pg/ml. Thus a single instillation of carteolol may increase the tissue blood velocity in ONH in the human eye. After topical dipivefrine, the IOP was significantly lower at 4.5 hr in the dipivefrine-treated eyes than that obtained in the control experiment (p < 0.05). Mean NB, BP and PR showed no significant change.

Adrenergic Agonists↗
PubMed1996

[A monkey chair specially designed for ophthalmic examinations and intraocular pressure measurement in the conscious cynomolgus monkey].

We constructed a monkey chair specially designed for ophthalmic examinations such as biomicroscopic examination, applanation tonometry etc. It was made of stainless steel and acrylic plastic, equipped with a protection plate for the experimenter, and adjustable to the size of the monkey. Using this chair, intraocular pressure (IOP) measurements of a fully conscious cynomolgus monkey were carried out at intervals of one or two hours from 10:00 AM to 10:00 PM. The IOP, at 6:00, 8:00 or 10:00 PM was compared with the IOP measured at the same time of the day after one or two weeks. The IOP while fully conscious showed diurnal variation (p < 0.001, ANOVA). The IOP measured at the same time of the day at one or two week intervals showed reasonable reproducibility.

Animals↗
PubMed1996

Time-course of changes in nicardipine effects on microcirculation in retina and optic nerve head in living rabbit eyes.

The effects of intravenous administration of a calcium antagonist, nicardipine, on microcirculation in the retina and optic nerve head (ONH) of rabbit eyes were investigated using a laser speckle microcirculation analyzer. The rabbit fundus was illuminated by an argon (blue) laser spot to measure the retina or by a diode laser spot to measure the ONH, and the image speckle was detected by an image sensor. The difference between the average of the speckle intensity (Imean) and the speckle intensity for successive scannings was calculated, and the ratio of Imean to this difference was defined as normalized blur (NB); a quantitative index of blood velocity in tissue. The average NB over the field measured (0.62 x 0.62 mm in the retina and 0.42 x 0.42 mm in the ONH) was calculated to give NBav, which was found to show a significant correlation with the retinal blood flow rate determined using a microsphere technique. In Dutch rabbits for measurement in the retina and in albino rabbits for measurement in the ONH (nicardipine group), 0.4 mL/kg of 0.01% nicardipine hydrochloride dissolved in physiological saline was injected intravenously into anesthetized animals. To serve as control, other groups of Dutch or albino rabbits were injected with 0.4 mL/kg of physiological saline. Mean femoral arterial blood pressure (FABPm) in the nicardipine group dropped to the minimum at 1 minute post-injection and this level remained significantly lower than that in the control group up to 15 minutes post-injection. The pulse rate, pH, Pco2 and Po2 of arterial blood, body temperature and the intraocular pressure did not show any significant changes during the experiment. The NBav obtained from the retina in the nicardipine group showed a significant transient decrease, probably due to the initial drop in the FABPm, followed by a significant increase after the FABPm returned to the baseline. The time-course of NBav obtained from the ONH in the nicardipine group showed little change. These results suggest that nicardipine may have considerable potential in the treatment of ocular diseases associated with insufficient retinal blood flow. The nicardipine effects observed here deserve to be studied further in human eyes.

Animals↗
PubMed1995

Non-contact, two-dimensional measurement of tissue circulation in choroid and optic nerve head using laser speckle phenomenon.

A new apparatus has been developed using the laser speckle phenomenon for non-contact, two-dimensional analysis of tissue circulation in the choroid and optic nerve head (ONH). The fundus was illuminated by a diode laser spot and its image speckle was detected by an image sensor. The difference between the average of the speckle intensity (Imean) and the speckle intensity for successive scannings was calculated, and the ratio of Imean to this difference was defined as normalized blur (NB), which is a quantitative index of blood velocity. The results were displayed on color graphic monitors showing the two-dimensional variation of the NB level in the measurement field. In the rabbit, this apparatus was used to study the relationship between the results of NB measurement and the choroidal blood flow determined by the microsphere technique, the relationship between NB obtained from the ONH tissue free of visible surface vessels and the ocular perfusion pressure (OPP) after a lethal injection of pentobarital, and the effect of intraocular pressure (IOP) on the NB in the choroid or in the ONH. A stepwise reduction in the OPP was introduced by elevating the IOP manometrically. The relative decrease in the average NB over the field measured, NBav, in the choroid with the reduction in OPP showed a significant correlation with the relative change in the blood flow rate determined using the microsphere technique (r = 0.60, P < 0.001). NBav in the ONH had a good correlation with the OPP after a lethal injection of pentobarbital (r = 0.98, P < 0.001). NBav in the choroid decreased with reduction in the OPP. Although NBav in the ONH was little affected by OPP change when OPP was above 40 mmHg, at OPP levels below 40 mmHg, NBav in the ONH decreased along with a reduction in the OPP. These results suggest that by using the present apparatus, the blood velocity in the choroid or ONH under various conditions can be studied non-invasively in the living eye.

Animals↗
PubMed1995

Pattern of visual field defects in normal-tension and high-tension glaucoma.

There are probably two major types of causative factors in open-angle glaucoma: pressure-dependent and pressure-independent. If clinical features such as the pattern of visual field defects differ between normal-tension and high-tension glaucoma, the differences may provide an insight for discriminating between the pressure-dependent and the pressure-independent damage in open-angle glaucoma. This article gives a brief review of the most recent studies including reports wherein progression or pattern of visual field defects in normal-tension and high-tension glaucoma or primary open-angle glaucoma are addressed. Further deterioration of the visual field in 5 years is expected in about 50% of eyes with normal-tension glaucoma in which intraocular pressure is one of the contributing factors. This figure may be greater than that seen in eyes with primary open-angle glaucoma where intraocular pressure is controlled with surgery in the middle teens. When eyes with normal-tension glaucoma and high-tension glaucoma or primary open-angle glaucoma were matched for extent of overall visual field loss, many studies noted a difference in the pattern of visual field defects between the two groups. Visual field defects in normal-tension glaucoma are relatively more localized and closer to fixation, especially in the nasal superior quadrant and may be more predominant in the lower hemifield. Results of other psychophysical tests also appear to support the above findings.

Glaucoma, Open-Angle↗
PubMed1995

Evaluation of albumin concentration in rabbit anterior chamber with laser flare-cell meter.

To find an appropriate way of using Kowa's laser flare-cell meter in evaluating the anterior chamber albumin concentration, we characterized the relationship among the flare intensity determined with the flare-cell meter in terms of photon count/ms (flare value), flare value converted to albumin concentration, and anterior chamber albumin concentration in drug-treated rabbit eyes. Flare measurement was done in rabbits that received intravenous administration of fluorescein isothiocyanate-labeled albumin and instillation of prostaglandin E1, pilocarpine, or tropicamide. Flare value, anterior chamber fluorescence, plasma fluorescence, and plasma albumin concentration were determined. Anterior chamber albumin concentration was calculated from the plasma albumin concentration and the corrected aqueous/plasma fluorescence ratio. The correlation between the flare value converted to albumin concentration (Albequiv) and the anterior chamber albumin concentration (Albac) had two phases: 1) Linear correlation was found when the flare value was below 100 photon count/ms: Albac = 0.53 Albequiv - 0.006, r = 0.98; 2) When the flare value was above 100 photon count/ms, the correlation was lower and had a different slope. In this condition, the Albac was correlated better with the flare value itself: Albac = 0.0042 [flare value] + 0.17, r = 0.88. The results suggested that anterior chamber albumin concentration is evaluated quantitatively from the converted flare value when the flare value is below 100 photon count/ms and from the flare value itself when the flare value is above that level.

Administration, Topical↗