Biomedical subjects

M Araie

Publications and source records attributed to M Araie.

At least 127 records · Page 7Linked to original sources

PubMed1994

[Noninvasive two-dimensional analysis of microcirculation in optic nerve head and choroid--calibration of the normalized blur (NB) value].

We have developed an apparatus using the laser speckle phenomenon for noninvasive two-dimensional measurements of the fundus microcirculation. The normalized blur of the speckle pattern (NB value) was adopted as an index of blood flow velocity in the tissue. The present study investigated whether the NB value can be also used as a quantitative index of the blood flow rate in the tissue. In experimental animals, an injection of a lethal dose of pentobarbital causes rapid reduction in the ocular perfusion pressure (OPP), which linearly correlates with blood flow rate in the ocular tissue. The NB in rabbit optic nerve head (ONH) tissue showed a linear correlation (r = 0.98, p < 0.001) with the OPP after injection of a lethal dose of pentobarbital, which suggested that the NB value parallels the blood flow rate in the ONH tissue. At various levels of OPP, the choroidal NB showed a good correlation (r = 0.60, p < 0.001) with the choroidal blood flow rate measured with microsphere technique. These results indicated that the NB value can be used as a quantitative index not only for the blood flow velocity but also for the blood flow rate in the tissue.

Animals↗

PubMed1994

[Noninvasive two-dimensional analysis of retinal microcirculation using the laser speckle phenomenon--II. Comparison of results with those obtained with the microsphere technique].

We have recently developed an apparatus for noninvasive two-dimensional analysis of the retinal microcirculation using the laser speckle phenomenon. The fundus is illuminated by an argon laser spot and its image speckle is detected by an area sensor. The difference between the average of output data and the output data for successive scannings of the image speckles at the sensor plane is calculated to give the value of normalized blur (NB), which is a quantitative index of tissue blood flow velocity. In pigmented rabbit eyes, the coefficient of reproducibility was 8% when the same area of retina was measured twice at 5-minute intervals and 13% at 24-hour intervals. The NB values in the retina free of visible vessels were recorded under various levels of intraocular pressure ranging from 10 to 80 mmHg and the results were compared with the blood flow rate determined with the colored microsphere technique. A linear correlation was found between the former and the latter, which suggested that the NB value also parallels the tissue blood flow rate.

Animals↗

PubMed1994

[Effect of calcium antagonist on retinal microcirculation evaluated with the laser speckle retinal microcirculation analyzer].

The effect of intravenous administration of a calcium antagonist on the retinal microcirculation in rabbit eyes was examined with a laser speckle retinal microcirculation analyzer. Under general anesthesia, 40 micrograms/kg of nicardipine, a calcium antagonist, was injected intravenously in the nicardipine group, and 0.4 ml/kg of saline in the control group. A quantitative index of blood flow velocity, the normalized blur (NB) value, in a retinal area (0. 62 x 0.62 mm) free of visible vessels, was recorded at 1-minute intervals for the first 5 minutes and at 5 minute-intervals for the next 85 minutes. The retinal NB value in the nicardipine group was significantly greater than in the control group, averaging 119%, 115%, 111%, 112%, and 116% of the initial value at 65, 75, 80, 85, and 90 minutes after injection, respectively. The blood pressure in the nicardipine group decreased significantly from 1 to 20 minutes after injection. The pulse rate, arterial pH, partial CO2 pressure, partial oxygen pressure, body temperature and intraocular pressure did not show significant change during the experiment. These results suggest, for the first time, that nicardipine increases the blood flow velocity in the retinal microvasculature in the living eye.

Animals↗

PubMed1994

[Study on risk factors for progression of visual field damage in normal-tension glaucoma].

We investigated the risk factors for progression of visual field damage in normal-tension glaucoma (NTG), using multiple regression analysis with the proportional hazard model and the life-table method. Seventy-six eyes of 56 patients with untreated NTG showing minor visual-field defects, with a mean deviation (MD) of > - 5 dB by the Humphrey (30-2) STATPAC program at entry, were included in the study. Endpoints of study follow-up were defined as follows: in HFA STATPAC 2 Glaucoma Change Probability Analysis, more than 5 points which significantly deteriorated at p < 0.05 were found at 2 consequent examinations (Criterion 1) or a significant decrease in the MD value at p < 0.025 was encountered at one examination or that at p < 0.05 at 2 consecutive examinations (Criterion 2). During the follow-up period (37 months, mean), 33 eyes (42%) satisfied Criterion 1 and 23 eyes (29%) Criterion 2. When Criterion 1 was employed, peripapillary chorio-retinal atrophy/disc ratio (p = 0.023), intraocular pressure (IOP) (p = 0.03) and cup/disc ratio (p = 0.035) were identified as significant risk factors for progression of visual-field damage. When Criterion 2 was employed, Contribution of cup/disc ratio (p = 0.065) and IOP (p = 0.145) was relatively high, but not significant. These results suggested an association of IOP and local vascular risk factors with progression of visual-field damage in NTG.

Female↗

PubMed1993

Effects of apraclonidine on intraocular pressure and blood-aqueous barrier permeability after phacoemulsification and intraocular lens implantation.

To evaluate the effect of topical apraclonidine on early postoperative intraocular pressure and blood-aqueous barrier permeability, we conducted a double-masked clinical trial in which 37 patients undergoing uncomplicated phacoemulsification and posterior chamber intraocular lens implantation were randomly assigned to treatment with 1% apraclonidine or its vehicle. One drop of 1% apraclonidine or its vehicle was instilled 1/2 hour preoperatively and immediately postoperatively. In addition to intraocular pressure, aqueous flare intensity was also determined before and after the operation by using a laser flare-cell meter. In the apraclonidine group, intraocular pressure showed no significant postoperative increase, whereas it showed a significant increase at six hours in the vehicle group (P < .01). Difference between intraocular pressure recorded at the end of the operation with the Tono-Pen II and that measured postoperatively was significantly greater in the vehicle group by 3.5 to 7.0 mm Hg (P < .05 to .01). In the apraclonidine group, the aqueous flare intensity was about half that in the vehicle group with significant differences at six (P < .05) and 24 (P < .01) hours.

Adrenergic alpha-Agonists↗

PubMed1993

A study on diurnal fluctuation of blood-aqueous barrier permeability to plasma proteins.

The diurnal change of blood-aqueous barrier permeability to protein molecules was investigated in 20 eyes of 10 normal volunteers. Simultaneous determinations of aqueous flow rate and the coefficient of entry into the anterior chamber (k(in)) for plasma protein were performed at different times of the day: (a) 0800 to 1100 hr; (b) 1900 to 2200 hr of the same day; (c) 0800 to 1100 hr of the next day; (d) 1400 to 1700 hr 1 week later; and (e) 0200 to 0500 hr of the following morning. Aqueous flow rate was determined by fluorophotometry and k(in) was calculated for each period from flow rate, plasma protein concentration, anterior chamber volume and aqueous protein concentration measured with a laser flare-cell meter. Calculated values for k(in) did not fluctuate significantly among the periods, and there were no significant changes in anterior chamber volume or plasma protein concentration. Aqueous protein concentration and flow rate showed diurnal fluctuations, the patterns of which inversely corresponded to each other. It was concluded that permeability of the blood-aqueous barrier to protein remains fairly stable over a 24-hr period and the diurnal variation of aqueous protein concentration is mostly attributable to that of aqueous flow rate.

Adult↗

PubMed1993

Visual field defects in normal-tension and high-tension glaucoma.

BACKGROUND: Differences in visual field characteristics between normal-tension glaucoma (NTG) and high-tension glaucoma (HTG) have not been established. This study re-examined the problem by pointwise between-group comparison of data obtained with the Humphrey 30-2 program. METHODS: Sixty-eight NTG cases with maximum intraocular pressure (IOP) of 21 mmHg or lower and 62 HTG cases with maximum IOP of 25 mmHg or greater with a mean deviation (STATPAC) greater than -10 decibels (dB) were included. Age, refraction, mean deviation, or sex ratio were matched between the two groups. Total deviation (STATPAC), the difference between the measured threshold and the age-corrected normal reference at each test point of the 30-2 program, was used for pointwise between-group comparisons. Another parameter, total deviation - mean total deviation, was introduced to normalize the total deviation by the overall visual field damage as an index of disease stage. Mean total deviation is the average of total deviations across the test field. Further, logistic discriminant analysis was applied to confirm that the difference at a questioned test point was due to the difference of disease type, but not disease stage, between the two groups. RESULTS: Comparison using total deviation and total deviation - mean total deviation gave similar results, which were collaborated by logistic discriminant analysis. For a given amount of visual field damage, an area just above the horizontal meridian was significantly more depressed in NTG, while HTG had significantly more diffuse visual field damage. CONCLUSION: Visual field defect of NTG differs from that of HTG, which may suggest that different regions of the optic disc are more susceptible to damage in NTG.

Adult↗

PubMed1993

Diurnal variation in intraocular pressure of normal-tension glaucoma eyes.

BACKGROUND: The nature of intraocular pressure (IOP) in normal-tension glaucoma (NTG) has not been studied in detail, although the information on the IOP is indispensable for diagnosis and treatment of NTG. METHODS: After at least six IOP measurements at daytime clinic, diurnal IOP was measured at 10:00 AM, 12:00 noon, 2:00, 4:00, 6:00, 8:00, 10:00 PM, 12:00 midnight, and at 3:00, 6:00, 8:00, and 10:00 AM by 1-day hospitalization in 118 NTG suspects. Four subjects with peak IOPs exceeding 21 mmHg were diagnosed as primary open-angle glaucoma (POAG) whose eyes all had mean clinic IOPs above 16 mmHg. The remaining 114 patients were diagnosed as having NTG, and their right eye data were used for analysis. RESULTS: The rhythmic nature of the diurnal IOP of NTG was analyzed by fitting the data to a cosine curve. In 54.4% of the eyes, the correlation between the measured IOP and the values predicted from the cosine curve was significant (r > 0.60, P < 0.05), and the equation, diurnal IOP = 13.9 + 1.7 cos 2 pi (t/24-0.40) mmHg, which was similar to that reported in normals, was obtained. Multiple regression analysis showed that the mean diurnal IOP was best predicted with the mean of the six clinic IOPs and systolic blood pressure (R2 = 0.67), and the peak diurnal IOP with the mean of six clinic IOPs (R2 = 0.50). The estimate fell within +/- 1 and +/- 2 mmHg of the actual value in 83% and 96% of the left eyes for the former and in 69% and 93% for the latter, respectively. No eyes with peak diurnal IOP exceeding 21 mmHg were overlooked with the cutoff IOP of 16 mmHg. CONCLUSION: The mean and peak diurnal IOP could be predicted with the mean of clinic IOPs.

Blood Pressure↗

PubMed1993

Sectorization of the central 30 degrees visual field in glaucoma.

PURPOSE: To determine an optimal sector pattern of the central 30 degrees visual field in glaucoma by mathematically analyzing the visual field data of primary open-angle glaucoma (POAG) without any assumption such as the retinal nerve fiber layer anatomy. METHODS: One hundred three visual fields of the 30-2 program of the Humphrey Field Analyzer obtained from 103 POAG patients of early to moderately advanced stage were included. Based on the interpoint correlation of deviation of the measured threshold value from the age-corrected normal reference value (total deviation, STATPAC), test points of the 30-2 program were mathematically clustered using the VARCLUS procedure, a new clustering algorithm developed by the SAS Institute. The sector value, which summarizes the visual field performance of the clustered test points (sector), also was calculated. RESULTS: The 30 degrees central visual field was divided into 15 sectors consisting of at least 3 points. The distribution of sectors was compatible with the projection of nerve fiber layers. There was no sector extending over the horizontal meridian, but the sector pattern was not completely symmetrical around it. Linear regression analysis of the sector values against the mean deviation (STATPAC) suggested that the index is useful in following visual field performance of each sector. CONCLUSION: The sector pattern and sector values obtained were considered useful in studying the visual field data of glaucoma.

Algorithms↗

PubMed1993

An application of laser speckle phenomenon for noninvasive two-dimensional evaluation of microcirculation in ocular fundus--a preliminary report.

A new instrument has been developed which uses the laser speckle phenomenon for noninvasive two-dimensional analysis of the microcirculation in the optic nerve head (ONH). The ONH is illuminated by a diode laser spot and its image speckle is detected by an area sensor. The difference between a pair of output data from successive scannings of the image speckles at the sensor plane is calculated and integrated for each pixel to obtain the average difference (AD) value, which is a quantitative index of blood flow velocity. The results are displayed in color graphics showing the two-dimensional variation of the AD value in the area of interest. In an in vitro model, the AD value correlated well with the speed of rotation of a ground glass in a range between 0 and 5 mm/second. Using this instrument, the effect of intraocular pressure (IOP) on the circulation was studied in the area of the rabbit ONH free of surface vessels. The coefficient of reproducibility was 4.7% when measured twice in this area at 5-minute intervals. A stepwise reduction in the ocular perfusion pressure (OPP) was introduced by elevating the IOP manometrically. The AD value was little affected by a change in OPP when the OPP was above 40 mmHg; while when the OPP was below 40 mmHg, a linear correlation was found between the AD value and the OPP. This finding agreed well with those of previous studies where the effect of the OPP on the ONH blood flow were studied using various invasive methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

[The central visual field defects in low-tension glaucoma. A comparison of the central visual field defects in low-tension glaucoma with those in primary open angle glaucoma].

To discover if there is difference in central visual field damage between low-tension glaucoma (LTG) and primary open angle glaucoma (POAG) eyes, the data obtained with the 10-2 threshold program of the Humphrey visual field analyzer were analysed using logistic discriminant analysis. One hundred and four LTG eyes from 65 case (maximum IOP < or = 21 mmHg) and 48 POAG eyes from 34 cases (maximum IOP > or = 25 mmHg) with early to moderately advanced visual field damage were included. There was no significant difference in mean deviation (MD, STATPAC), refraction, or age between the 2 groups. The analysis demonstrated that an arcuate area in the upper central 5-10 degrees of the visual field was significantly more depressed in LTG than in POAG eyes.

Aged↗

PubMed1993

Effects of topical application of UF-021, a novel prostaglandin-related compound, on aqueous humor dynamics in rabbit.

The mechanism underlying the intraocular pressure (IOP) lowering effect of a novel prostaglandin-related compound, (+)-isopropyl Z-7-[(1R,2R,3R,5S)-3,5-dihydroxy-2-(3-oxodecyl)-cyclopentyl]hept-5 -enoate (UF-021), and the influence of this new hypotensive agent on the permeability of the blood-aqueous barrier (BAB) were studied in albino rabbits. A single instillation of 0.06% UF-021 significantly lowered the IOP with a peak reduction of 5.2 mmHg without changing the aqueous flow rate. Uveoscleral outflow and outflow facility to general blood circulation were both increased. The BAB permeability evaluated with fluorescein isothiocyanate-labeled rabbit albumin (FITC-RA) showed approximately sixfold increase after a single instillation of 0.06% UF-021, which suggested a drug-induced compromise of the rabbit BAB.

Administration, Topical↗

PubMed1993

[A comparative study of visual field damage in low-tension and primary open-angle glaucoma].

We compared the results of visual field examination obtained with a Humphrey 30-2 program between 57 eyes of 57 low-tension glaucoma (LTG) and 57 eyes of 57 primary open-angle glaucoma (POAG; max IOP > or = 25 mmHg) cases, whose mean deviation (MD) given by STATPAC was > -10 dB. MD, age, and refraction showed no differences between the two groups. Corrected pattern standard deviation (CPSD) was significantly higher in the LTG group (p < 0.01). The total deviation (TD), deviation from the age-corrected normal reference, was found to be significantly lower by about 5 dB in the LTG group at two test points nasal-superior to the fixation point (Wilcoxon rank sum test, p < 0.01). Logistic discriminant analysis carried out to exclude a subtle difference in the distribution of the stage of disease between the two groups confirmed a significant between-group difference at the above-mentioned points. Furthermore, to compare the unevenness of visual field in the two groups, [TD-mean TD] was calculated, where mean TD was the average of 70 points of TD excluding the uppermost four points, and the same two points obtained above were found to decrease significantly in LTG, while all points were diffusely damaged in POAG. These results may imply a difference in the mechanism of visual field damage between LTG and POAG.

Adult↗

PubMed1993

[An apparatus using laser speckle phenomenon for noninvasive 2-dimensional analysis of microcirculation in the optic nerve head].

A new instrument using the laser speckle phenomenon for noninvasive 2-dimensional analysis of the microcirculation in the optic nerve head (ONH) was developed. The ONH was illuminated with a diode laser spot and its image speckle was detected by an area array sensor. The difference between a pair of output data for successive scannings of the image speckles at the sensor plane was calculated and integrated for each pixel to obtain the average difference (AD), which is a quantitative index of blood speed. The results were displayed in color graphics showing the 2-dimensional variation of the AD level in the area of interest. The AD had good correlation with the speed of ground glass in a range between 0 and 8 mm/sec. Using this instrument, the effect of intraocular pressure (IOP) on the circulation in the area of the rabbit ONH free from surface vessels was studied. The coefficient of reproducibility was 4.7% when measured in this area twice at 5-minute intervals. A stepwise reduction in the ocular perfusion pressure (OPP) was introduced by elevating the IOP manometrically. The AD was little affected by OPP change when OPP was above 40 mmHg, but with the OPP below 40 mmHg, a linear correlation was found between the AD and OPP.

Animals↗

PubMed1993

[A study of para-foveal color vision in normal-tension and primary open angle glaucoma eyes].

A perimetric color vision test developed by Iijima et al. for evaluating parafoveal color vision provides information regarding local retinal function which can not be evaluated by other color vision tests. Using this method, we investigated para-foveal color sensitivity in normal-tension glaucoma (NTG) and primary open angle glaucoma (POAG) eyes whose glaucomatous visual field change determined with the central 30-2 program of the Humphrey visual field analyzer was confined to either the upper or the lower hemifield. The examined eyes had no abnormalities in ocular media with best corrected visual acuity of 1.0 or higher, and age, refraction, mean deviation, and extent of visual field loss were matched between NTG and POAG eyes. In the para-foveal area of the spared hemifield, acquired blue-yellow dyschromatopsia was detected in 52.3% of the POAG eyes and in 11.3% of the NTG eyes (p < 0.02, chi 2-test), and in damaged hemifield, it was found in 76.1% of the POAG eyes and 80.7% of the NTG eyes. We suggest that visual function is more diffusely damaged in POAG than in NTG and that the perimetric color vision test is useful for detecting glaucomatous damage which cannot be detected with conventional light threshold measurements.

Adult↗

PubMed1993

[An apparatus using laser speckle phenomenon for noninvasive 2-dimensional analysis of choroidal microcirculation].

A new instrument using the laser speckle phenomenon for noninvasive 2-dimensional analysis of the choroidal microcirculation was developed. The fundus was illuminated with a diode laser spot and its image speckle was detected with an area sensor. The difference between the average of the output data (I-mean) and the output data from successive scannings of the image speckles at the sensor plane was calculated and integrated to give as D-mean, and I-mean/D-mean was defined as normalized blur (NB), which is a quantitative index of blood flow velocity. The results were displayed in color graphics showing the 2-dimensional variation of the NB level in the area of interest. The NB had good correlation with the speed measured on ground glass in the range between 2 and 130mm/sec. Using this instrument, the effect of intraocular pressure on the chroidal circulation of the rabbit was studied. The coefficient of reproducibility was 6.9% when measured in the same area twice at 5-minute intervals. A stepwise reduction in the ocular perfusion pressure was introduced by elevating the intraocular pressure manometrically. A linear correlation was found between the NB and the ocular perfusion pressure.

Animals↗

PubMed1993

[Combined posterior chamber intraocular lens implantation and trabeculectomy--a life-table analysis of postoperative clinical course].

Postoperative courses of 68 eyes of 58 glaucoma patients who underwent posterior chamber intraocular lens implantation combined with trabeculectomy were studied retrospectively. The visual acuity was 0.5 or better in 66% of the eyes at 3 months postoperatively. The average intraocular pressure (IOP) was below 15 mmHg till 16 months postoperatively. An analysis of the postoperative course using the life-table method of Kaplan-Meier revealed that the probability of successful IOP control with medication was 83% at 18 months and 47% without medication. The subjects aged 75 years or older showed significantly higher success probability than those younger than 75 years, while types of glaucoma, the preoperative IOP control, location of conjunctival or sclerocorneal incision, postoperative 5-fluorouracil (5-FU) injections or surgical intervention on the iris had no significant effects on the probability of successful IOP control. The probability of subsistence of functional filtering bleb was 24% at 18-month follow-up, on which postoperative administration of 5-FU of 35 mg or more had a favorable effect.

Aged↗

PubMed1993

Movement of fluorescein and its glucuronide across retinal pigment epithelium-choroid.

PURPOSE: To characterize movement of fluorescein and its glucuronide across the blood-retinal barrier. METHODS: Retinal pigment epithelium (RPE)-choroid preparations from New Zealand albino rabbit were sealed in an Ussing-type chamber in a stabilized condition for 3 hr, where movement of fluorescein and fluorescein glucuronide across the RPE-choroid was studied under a short circuit condition. RESULTS: The outward (vitreous-choroid) permeability to fluorescein determined at a concentration of 15 mumol/l was about 4 times greater than the inward (choroid-vitreous) permeability (P < 0.01). The outward permeability was significantly decreased by 50-65% by metabolic or competitive inhibitors (1 mumol/l ouabain, 10 mumol/l 2,4-dinitrophenol, 100 mumol/l probenecid, 30 mmol/l hippurate, or 5 mmol/l iodipamide), whereas the inward permeability was not affected by any of the above competitive inhibitors. As the fluorescein concentration was increased from 15 to 150 mumol/l, the net fluorescein movement across the tissue indicated saturation, and a Lineweaver-Burk plot gave an apparent Km of 26 mumol/l and Vmax of 1.56 nmol/hr/cm2. The outward permeability to fluorescein glucuronide determined at 15 mumol/l was about double the inward permeability (P < 0.01) and about 1/3 of the outward permeability to fluorescein (P < 0.01). The outward permeability to fluorescein glucuronide was significantly decreased by about 50% by 1 mumol/l ouabain, 10 mumol/l 2,4-dinitrophenol, or 100 mumol/l probenecid, whereas the inward permeability was not affected by 100 mumol/l probenecid. CONCLUSION: These results suggest that the majority of the outward fluorescein movement across the tissue and part of that of fluorescein glucuronide depends on an active transport mechanism, whereas the inward movement of both fluorescein and fluorescein glucuronide occurs by a passive mechanism.

2,4-Dinitrophenol↗