Biomedical subjects

Y Kitazawa

Publications and source records attributed to Y Kitazawa.

At least 91 records · Page 5Linked to original sources

PubMed1997

Use of antifibrosis agents and glaucoma drainage devices in the American and Japanese Glaucoma Societies.

PURPOSE: To investigate practice patterns among glaucoma subspecialists in the American Glaucoma Society (AGS) and the Japanese Glaucoma Society (JGS), regarding use of antifibrosis agents and glaucoma drainage devices. METHODS: An anonymous survey incorporating 10 clinical situations was mailed to all AGS and JGS members in December 1995. RESULTS: Half of the AGS (105 of 210), and JGS (25 of 50) members returned surveys. Most respondents (51-87%) preferred trabeculectomy with adjunctive mitomycin for all 10 clinical situations. Mitomycin concentrations varied from 0.1 to 0.8 mg/ml (range of means for 10 situations 0.31-0.39 mg/ml) and intraoperative application times ranged from 5 s to 7 min (range of means for 10 situations 2.5-4.6 min). Preferences for either no antifibrosis agent (up to 39%) or 5-fluorouracil (up to 29%) were highest in primary trabeculectomy. Thirty-seven percent to 64% of AGS members used glaucoma drainage devices, especially after complicated postsurgical glaucomas (after penetrating keratoplasty, scleral buckling, or pars plana vitrectomy) and in neovascular glaucoma, but few JGS members used them. Large differences between university- and private practice-based AGS members were found only in mitomycin use for primary trabeculectomy (33% vs. 52%, respectively; p = 0.07) and for complicated postsurgical glaucomas (46% vs. 70%, respectively; p = 0.03). CONCLUSIONS: Trabeculectomy with mitomycin was the preferred surgical procedure among AGS and JGS members in the clinical situations surveyed. Mitomycin concentration and time of application varied widely. Many respondents used 5-fluorouracil or no antimetabolite in primary trabeculectomy. Glaucoma drainage devices were widely used for complicated glaucomas in the United States.

Chemotherapy, Adjuvant↗

PubMed1997

Glaucomatous visual field defects: their characteristics and how to detect them.

Functional defects of glaucomatous optic neuropathy are reviewed and summarized. Glaucomatous visual field defects are basically comprised of four major patterns: an isolated scotoma, an arcuate scotoma, a nasal step, and generalized depression. The field loss progresses conforming to the optic nerve head and retinal nerve fiber changes. Interpretation of the visual field and some tips of the interpretation are outlined in addition to describing differential diagnosis. Lastly, blue-on-yellow perimetry and high-pass resolution perimetry, both of which are promising tools for early detection of glaucoma, are introduced.

Glaucoma↗

PubMed1997

Appositional angle closure in eyes with narrow angles: comparison between the fellow eyes of acute angle-closure glaucoma and normotensive cases.

PURPOSE: To identify topologic features of eyes with acute primary angle-closure glaucoma before an attack as compared with those features in normotensive cases, assuming that untreated fellow eyes of acute primary angle-closure glaucoma are candidates for an acute attack. METHODS: A total of 50 eyes (12 fellow eyes of acute primary angle-closure glaucoma and 38 normotensive cases with a closure-possible narrow angle) were prospectively examined by ultrasound biomicroscopy under dark-room conditions. All eyes were examined before surgical or laser intervention and had normal pupillary reaction without any topical drugs. Four predetermined angle locations per eye were examined. Parameters regarding the chamber angle configuration were measured and compared between the two groups. RESULTS: Appositional angle closures were observed in 27 locations in fellow eyes and in 48 locations in normotensive eyes with a closure-possible narrow angle. The incidence was statistically different between the two groups (69.2% in the fellow eyes and 48% in the normotensive eyes). Appositional angle closures beginning at the entrance of the angle were more frequently detected in the fellow eye group. The distance between the iris root and the bottom of the angle was significantly different between the two groups. CONCLUSION: The fellow eyes of acute primary angle-closure glaucoma have different topologic features from normotensive narrow-angled eyes and a higher incidence of appositional closure that may predispose these eyes to an imminent acute attack.

Acute Disease↗

PubMed1997

Iris-color change developed after topical isopropyl unoprostone treatment.

PURPOSE: To present a case in which iris pigmentation developed after treatment with isopropyl unoprostone, an analogue of a prostaglandin metabolite. METHODS: Case report. RESULTS: A Japanese man with dark brown irises, treated unilaterally with isopropyl unoprostone, developed iris-color change in the treated eye after a 20-month treatment. CONCLUSIONS: Isopropyl unoprostone can induce iris pigmentation as does latanoprost.

Administration, Topical↗

PubMed1996

Comparative 1H-NMR studies on the physical state of water in soft contact lens and mouse lens.

The physical state of water in mouse lenses (2-, 4- or 8-wk-old) and soft contact lenses (SCLs, water content from 18.4 to 79.2%) were studied by measuring spin-lattice relaxation times (T1) and apparent intermolecular cross-relaxation times (TIS) from irradiated protein or polymer protons to water protons, using 360 MHz 1H-NMR spectrometer at 25 degrees C. (1) 1/T1 values of SCLs increased gradually with increasing dry weight (W(%)). 1/TIS values of SCLs were approximately zero at W of 20.8 and 26.8%, increased gradually from 26.8% and then steeply above approximately 50%. (2) A plot of 1/T1 vs. W(%) of mouse lenses was almost equal to that of SCLs. However, a plot of 1/TIS vs. W(%) was an approximately straight line with the intercept at W of 23% and with the slope which is almost equal to that of SCLs above W of approximately 50%. The plot of 1/TIS vs. W(%) of mouse lenses might indicate the significant change in the physical state of water and/or protein-water interactions above W of 23%.

Age Factors↗

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

Paraquat causes S-phase arrest of rat liver and lung cells in vivo.

We examined the in vivo effect of paraquat on the cell cycle in rat liver and lung tissues and the protective effect of tungsten (a xanthine oxidase inhibitor) on paraquat toxicity. The bromodeoxyuridine/propidium iodide double-staining method and flow cytometry were used for cell cycle assessment. Wistar rats were fed a standard diet or a tungsten-enriched diet were injected intravenously with 20 mg/kg paraquat, while uninjected rats served as controls. At 1, 3, and 5 days after paraquat injection, the liver and lungs were removed for examination following in vivo labeling with 20 mg/kg bromodeoxyuridine for 1 h. Liver and lung cells were isolated and incubated with an anti-bromodeoxyuridine antibody and with propidium iodide for DNA staining. Flow cytometry showed that the S-phase cell populations in the liver and lungs of paraquat-injected rats fed a standard diet were increased markedly on days 1 and 3 after injection compared with the control levels. However, on day 5 the liver cells had nearly returned to normal, while the S-phase population remained high in the lungs. In contrast, the S-phase cell populations of liver and lung tissue showed no increase after paraquat injection in rats fed a tungsten-enriched diet. These findings suggest that paraquat-induced cytotoxicity is more prolonged in the lungs than in the liver. In addition, paraquat toxicity appears to be mediated by xanthine oxidase and xanthine oxidase inhibitors may be useful an an antidote.

Animals↗

PubMed1996

In vivo detection of perineural circular arterial anastomosis (circle of Zinn-Haller) in a patient with large peripapillary chorioretinal atrophy.

PURPOSE: In vivo visualization of perineural circular arterial anastomosis (circle of Zinn-Haller) has been considered impossible because of the arterial circle's location in the sclera. We investigated whether the circle of Zinn-Haller could be detected in a glaucoma patient who had a large area of temporal peripapillary chorioretinal atrophy. METHODS: We performed both scanning laser Doppler flowmetry and indocyanine green angiography with a scanning laser ophthalmoscope in the same patient. RESULTS: In the area of peripapillary atrophy, a circumferential vascular loop consistent with a portion of the circle of Zinn-Haller could be detected by the two imaging methods. CONCLUSION: The circle of Zinn-Haller can be visualized in vivo because of the peripapillary atrophy.

Arteries↗

PubMed1996

Correlation between peripapillary atrophy and optic nerve damage in normal-tension glaucoma.

PURPOSE: To investigate the correlation between peripapillary atrophy and visual field defects as well as optic nerve head configurations in patients with normal-tension glaucoma (NTG). METHODS: Topographic measurements for peripapillary atrophy and optic nerve head using confocal scanning laser tomography and automated static threshold perimetry were performed on 102 eyes of 51 patients with NTG. Peripapillary atrophy was divided into (1) a central zone (zone Beta) with visible, large choroidal vessels and sclera, and (2) a peripheral zone (zone Alpha) with irregular hyper- and hypopigmentation. The area, angular extent around the disc, and radial extent of each zone were measured. RESULTS: The area and extent of zone Beta increased significantly with increasing visual field defects expressed in terms of mean deviation, corrected pattern standard deviation, central visual field defects within 5 degrees of fixation, and superior hemifield defects (r = 0.3770-0.5291, P < 0.01). The angular extent of zone Beta represented localized field defects better (r = 0.5217, P < 0.001) than diffuse field defects (r = -0.3770, P < 0.01). Zone Beta significantly correlated with optic nerve head topography. Intraindividual right-left-side differences of corrected pattern standard deviation showed the highest correlation with the side differences of zone Beta area (r = 0.6305, P < 0.001). The location of visual field defects correlated significantly with the location of peripapillary atrophy (chi-square = 9.0484, P = 0.011). Zone Alpha was not significantly correlated with visual field defects or optic nerve head configurations (P > 0.05). CONCLUSION: Peripapillary atrophy is significantly associated with functional and structural optic nerve damage in NTG.

Adult↗

PubMed1996

Prevention of visual field defect progression with brovincamine in eyes with normal-tension glaucoma.

PURPOSE: A prospective investigation of the effect of brovincamine fumarate, a Ca2+-channel blocker, on visual field changes in normal-tension glaucoma (NTG). METHODS: A total of 28, age- and field-matched, patients with NTG were allocated randomly to either brovincamine fumarate (20 mg 3 times daily) or placebo (3 times daily). The patients were followed at least every 4 months for a minimum of 2.5 years, and visual field examinations were carried out at least every 6 months. The mean follow-up periods (+/-standard deviation) were 39.1 +/- 8.7 months in the brovincamine-treated group and 37.9 +/- 10.1 months in the placebo group. Stepwise discriminant analyses were performed to separate the patients who showed improvement of their visual fields from those who failed to improve in the brovincamine-treated group, and to identify factors that may determine the visual field prognosis of all patients with NTG enrolled in the study. RESULTS: In the brovincamine-treated group, six patients showed visual field improvement, whereas none showed improvement in the placebo group using the Statpac 2 linear regression analysis. Discriminant analyses identified better cold recovery rate and higher initial systolic blood pressure to be significantly contributory to a favorable outcome in the brovincamine-treated group, and the use of brovincamine, better cold recovery rate, and higher initial systolic blood pressure were identified to be significantly contributory to a favorable prognosis in all subjects. CONCLUSION: Brovincamine seems to have a favorable effect on visual field in at least some patients with NTG.

Administration, Oral↗

PubMed1996

Effects of endothelin A and B receptors on aqueous humor dynamics in the rabbit eye.

This study attempted to clarify the role of endothelin A and B (ETA and ETB) receptors in modulating aqueous humor dynamics in the rabbit eye. Intraocular pressure (IOP), aqueous flow, total outflow facility, and uveoscleral outflow were measured before, and 24 hours after, intravitreal injection (20 microliters) of a selective ETB agonist, sarafotoxin S6c (SRTX S6c, 10(-5) M), into one eye and its vehicle into the contralateral eye. The measurements were also performed before and after injection of a selective ETA antagonist, 97-139 (10(-2) M) + ET-1 (10(-5) M) into one eye, and vehicle + ET-1 (10(-5) M) into the contralateral eye. In the SRTX S6c-treated eye, total outflow facility increased significantly by 106% compared with that in the vehicle-treated eye 24 hours after injection; aqueous flow and uveoscleral outflow failed to change significantly. The ETA antagonist 97-139 inhibited the decrease in aqueous flow partially, but significantly, but failed to inhibit the increase in total outflow facility caused by ET-1. Therefore, both ETA and ETB play a significant role in modulating aqueous humor dynamics in the rabbit eye. ETA can modulate aqueous humor production, at least in part. ETB can modulate total outflow facility, and the possibility for ETB in modulating aqueous humor formation cannot be ruled out.

Animals↗

PubMed1996

Ocular hypotensive mechanism of topical isopropyl unoprostone, a novel prostaglandin metabolite-related drug, in rabbits.

This study was performed to clarify the ocular hypotensive mechanism of topical isopropyl unoprostone (unoprostone), a novel prostaglandin (PG) metabolite-related drug, in the rabbit eye. The intraperitoneal administration of indomethacin (50 mg/kg) 1 hour before administration of topical 0.12% unoprostone partially diminished the intraocular pressure (IOP) reduction, and completely blocked the increase in aqueous PGE2 concentration caused by unoprostone. Aqueous humor dynamics measurements in the unoprostone- and the vehicle-treated contralateral eyes with indomethacin pretreatment revealed that aqueous flow determined by fluorophotometry was not significantly different, 2.3 +/- 0.3 and 2.4 +/- 0.2 microliters/min, respectively; the total outflow facility measurements determined by the two-level constant pressure perfusion method were 0.20 +/- 0.01 and 0.14 +/- 0.01 microliters/min/mmHg, respectively (p < 0.05); the uveoscleral outflow measurements determined by the fluorescein isothiocyanate-dextran perfusion method were 0.49 +/- 0.02 and 0.46 +/- 0.02 microliters/min, respectively (p < 0.05). The magnitude of the IOP reduction induced by unoprostone was estimated to be 5.2 mmHg, which agrees well with the actual IOP reduction. In conclusion, unoprostone lowers the IOP by affecting aqueous outflow pathways, primarily the pressure-dependent conventional pathway and the secondary uveoscleral outflow pathway in rabbits. Endogenous PGs induced by topical unoprostone are also involved in lowering the IOP in rabbits.

Administration, Topical↗

PubMed1996

Surgery for refractory glaucoma.

PURPOSE: To determine the surgical outcome of mitomycin trabeculectomy in patients with refractory glaucoma. METHODS: Sixty-six eyes of 52 patients with refractory glaucoma underwent mitomycin trabeculectomy. Mitomycin was applied for five minutes only once during trabeculectomy. The follow-up period was six to 61 months. RESULTS: Cumulative success probability was calculated using Kaplan-Meier life-table analysis assuming the cut-off postoperative IOP to be 20 mmHg or IOP reduction by at least 20% in eyes with preoperative IOP 24 mmHg. At the end of 61-month follow-up the success probability was 80% +/- 6% without postoperative ocular hypotensive medication (complete success) and was 95% +/- 3% regardless of postoperative antiglaucoma medication (overall success), respectively. CONCLUSION: The data suggest that mitomycin trabeculectomy is efficacious in reducing IOP in patients with refractory glaucoma.

Adolescent↗

PubMed1996

The effects of intravitreally injected endothelin-1 on the iris-ciliary body microvasculature in rabbits.

PURPOSE: We previously reported that intravitreal injection of 0.5 microg of endothelin-1 (ET-1) caused both a sustained reduction of intraocular pressure (IOP) and decreased aqueous production in the rabbit eye. On the theory that these effects might have resulted from a sustained reduction of blood flow to the ciliary body due to ET-1-mediated vasoconstriction, in the present study we attempted to determine if ET-1 causes any changes in the vascular caliber of the iris-ciliary body. METHODS: ET-1 solution (0.5 microg) was injected into the vitreous of one eye of each of 10 albino rabbits; the same amount of vehicle was injected into the contralateral eyes. One h following these injections in five of the rabbits and 24 h following them in the other five rabbits, ocular microvascular castings were obtained under controlled physiologic conditions, and the amount of vasoconstriction of the arterioles branching from the major arterial circle of the iris (MAC) and supplying the iris-ciliary body was measured by a scanning electron microscope and expressed as a percentage. RESULTS: The ET-1 caused a statistically significant focal vasoconstriction in the treated eyes as compared with the contralateral, control eyes (9.9% at 1 h and 6.2% at 24 h; both P = . 0001). CONCLUSIONS: Intravitreally injected ET-1 caused statistically significant, but only mild vasoconstriction of the arterioles supplying the ciliary processes.

Animals↗

PubMed1996

[Effects of amosulalol hydrochloride on intraocular pressure and aqueous humor dynamics in the rabbit eye].

The effects of amosulalol, which blocks alpha 1 adrenoceptors selectively and beta receptors nonselectively almost to the same extent, on intraocular pressure (IOP) and aqueous humor dynamics were studied in pigmented rabbits. Administration of topical amosulalol (0.5%) resulted in a significant difference in IOP between the treated and the contralateral eyes from 0.5 to 6 hours, and the maximum IOP reduction, 6.0 +/- 0.4 mmHg (mean +/- standard error), was observed at 2 hours after administration. Aqueous humor dynamics measurements (mean +/- standard error) in the amosulalol (0.5%)-treated and the contralateral eyes revealed that total outflow facility determined by the two-level constant pressure perfusion method was not significantly different, 0.14 +/- 0.01 and 0.12 +/- 0.01 microliter/min/mmHg, respectively; the aqueous flow measurements determined by fluorophotometry were 3.0 +/- 0.1 and 3.4 +/- 0.2 microliters/min, respectively (p < 0.05, -11%); the uveoscleral outflow measurements determined by the fluorescein isothiocyanate-dextran perfusion method were 0.53 +/- 0.04 and 0.46 +/- 0.04 microliter/min, respectively (p < 0.05, +15%). In conclusion, amosulalol lowers the IOP by inhibiting aqueous production and increasing uveoscleral outflow.

Adrenergic alpha-Antagonists↗

PubMed1996

[Temporal modulation transfer function in normal-tension glaucoma patients].

In an attempt to detect patients in an early stage of glaucoma, a new screening test, the Flicker System, by which temporal modulation transfer function is evaluated, was performed in 64 normal-tension glaucoma patients and 65 normal eyes. The early stage of glaucoma, i.e., stage 0-1 of Aulhorn-Greve's classification, showed a significant decrease of the modulation in the range from 20 to 45 Hz in comparison with normal eyes (p value < 0.05). The moderate stage of glaucoma of stages 2-3 also revealed significantly decreased values of the modulation in the range from 14 to 55 Hz. In the range from 25 to 45 Hz, the reduction of modulation in the glaucoma with diffuse visual defect was more profound than in glaucoma with localized or mixed defects. The results seem to be compatible with the presence of diffuse visual function deficit in glaucoma.

Adult↗

PubMed1996

Effects of BQ-123, an ETA recepter-selective antagonist, on changes of intraocular pressure, blood-aqueous barrier and aqueous prostaglandin concentrations caused by endothelin-1 in rabbit.

Endothelin-1 (ET-1) is known to affect the intraocular pressure (IOP) in rabbits. We reported that intravitreally administered ET-1 induced biphasic IOP response, an early transient IOP rise followed by a subsequent prolonged decrease. In an attempt to clarify the role of ET receptor subtypes in the IOP responses following ET-1 injection, we studied the effects of ETA receptor-specific antagonist, BQ-123, in rabbits. We also evaluated the possible role of prostaglandins (PGs) and the disruption of the blood-aqueous barrier (BAB) following ET-1 injection in modulating the IOP change. BQ-123 (126.5 or 12.6 micrograms) was injected into the vitreous (20 microL/eye) of one eye in a group of 5 rabbits. Contralateral eyes received the same amount of vehicle in a masked randomized fashion. The same amount of ET-1 (0.5 or 0.05 micrograms) was injected intravitreally 30 minutes later into both eyes. IOP was measured prior to and periodically up to 120 hours after injection using a calibrated pneumatonometer. In another experiment BQ-123 (126.5 micrograms) was injected into one eye of 4 rabbits and the other eye served as a control to observe the effect of BQ-123 on the IOP. One hour and 24 hours following the injection of BQ-123 and ET-1, approximately 100 microL of aqueous humor was withdrawn by paracentesis. Protein concentration was measured by Lowry's method and PGE2 concentration, by radioimmunoassay. BQ-123 had no effect on the IOP when used alone. When used in combination with ET-1, BQ-123 (126.5 micrograms) significantly inhibited both the IOP rise (0.5-1 hour) and the reduction (24-72 hours) caused by ET-1 (0.5 microgram). BQ-123 (12.6 micrograms) also significantly inhibited the IOP reduction (6-8 hours and 72-96 hours) caused by ET-1 (0.05 micrograms). Pre-injection of BQ-123 (126.5 micrograms) significantly suppressed the increase in the aqueous protein and the PGE2 concentration both at 1 and 24 hours. The IOP response and the elevation of aqueous protein and PGE2 concentration following ET-1 injection are at least partly mediated by ETA receptors.

Animals↗

PubMed1996

Epithelial barrier function of the filtering bleb conjunctiva and the cornea after trabeculectomy with mitomycin C.

PURPOSE: To evaluate epithelial barrier function of the filtering bleb conjunctiva and the cornea after trabeculectomy with adjunct, intraoperative mitomycin C, by using a newly developed slit-lamp fluorophotometer. SUBJECTS AND METHODS: Thirteen patients with normal-tension glaucoma with a cystic filtering bleb who had undergone unilateral trabeculectomy with mitomycin C only once at least 1 year previously were subjected to the study. Epithelial barrier function of the bleb conjunctiva and the cornea in the operated eye was evaluated using an Anterior Fluorometer FL-500 to measure the uptake of topically applied fluorescein. RESULTS: Fluorescein uptake (nanograms per milliliter, mean +/- standard error) by the bleb conjunctiva (1,857 +/- 380) was not significantly different from either the uptake by the superior bulbar conjunctiva in the operated eyes, located approximately 90 degrees C away from the filtering bleb (1,974 +/- 258), or the uptake by the conjunctiva in the intact eyes, located symmetrically against the bleb (1,913 +/- 248). The corneal uptake in the operated eye (56.1 +/- 10.2) was not significantly different from that in the intact eye (53.5 +/- 8.3). CONCLUSIONS: Epithelial barrier function of the cystic filtering bleb conjunctiva and the cornea long after trabeculectomy with mitomycin C was demonstrated to be almost identical to that of the control.

Aged↗