Optic disc diameter measurement using planimeter and scanning laser ophthalmoscope.
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Glaucoma↗
Biomedical subjects
E Chihara
Publications and source records attributed to E Chihara.
Covariation of optic disc measurements and ocular parameters in the healthy eye.
To understand the variations in optic disc topography that may affect the local susceptibility of nerve fibers to glaucomatous damage, we evaluated the correlations between optic disc topography and selected ocular parameters in 210 normal eyes of healthy Japanese. In the total study group, eyes with a longer axial length had a longer distance between the disc and foveola, a larger index of ovalness and a larger disc (P < 0.01). A longer disc-foveola distance correlated with a larger index of ovalness (P < 0.01). The optic discs of severely myopic eyes had a considerably different structure from other eyes. Eyes with a tilted optic disc were unique in that the area of the optic disc was not large despite a positive correlation with long axial length (P < 0.01) a long disc-foveola distance (P < 0.01), and a large index of ovalness (P < 0.01). Eyes with a rotated optic disc were another special case. This eye type correlated in a contradictory fashion with two parameters: a large axial length (P < 0.01) and a short disc-foveola distance (P < 0.01). These findings suggest that changes in optic disc topography or susceptibility to glaucomatous damage correlate with selected ocular parameters but are not completely parallel.
Anthropometry↗
Right atrial pressure and forearm blood flow during prolonged exercise in a hot environment.
Right atrial pressure (RAP) at rest is known to be reduced by an increase in skin blood flow (SkBF) in a hot environment. However, there is no clear evidence that this is so during exercise. To clarify the effect of the increase in SkBF on RAP during exercise, we measured forearm blood flow (FBF) (as an index of SkBF) and RAP continuously using a Swan-Ganz catheter in five male volunteers exercising on a cycle ergometer at 60% of peak aerobic power for 50 min in a hot environment (30 degrees C, relative humidity 20%). Cardiac output increased from 5.5 +/- 0.2 l/min at rest to 17.9 +/- 1.2 l/min (mean +/- SE, P < 0.01) in the first 10 min of exercise and then remained steady until the end of exercise. FBF did not change significantly during the first 5 min, but then increased from 2.7 +/- 0.5 ml/100 ml per min at rest to 10.8 +/- 1.7 ml/100 ml per min (P < 0.001) by 25 min as pulmonary arterial blood temperature (Tb) rose from 37.0 +/- 0.1 degrees C to 38.1 +/- 0.1 degrees C (P < 0.001). FBF then reached a plateau, despite a continuing increase in Tb. RAP increased significantly from 4.3 +/- 0.8 to 7.6 +/- 1.2 mm Hg (P < 0.001) during the first 5 min of exercise and then gradually declined to 6.1 +/- 1.0 mm Hg by 25 min (P < 0.001 vs. 5 min) and further to 5.7 +/- 1.0 mm Hg by 50 min, a value not significantly higher than at rest.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Right atrial pressure and ANP release during prolonged exercise in a hot environment.
To investigate the relationship between right atrial pressure (RAP) and atrial natriuretic peptide (ANP) release during prolonged exercise in a hot environment (30 degrees C, 20% relative humidity), we studied with a Swan-Ganz catheter five male volunteers exercising on a cycle ergometer at 60% of peak aerobic power for 50 min. The ANP level increased from 14 +/- 3 (SE) to 69 +/- 10 pg/ml (P < 0.001) during the first 10 min of exercise as RAP rose from 4.3 +/- 0.8 to 6.9 +/- 1.1 mmHg (P < 0.001). The 10-min ANP level was significantly correlated with RAP (r = 0.88, P < 0.05) but not with heart rate, pulmonary arterial blood temperature, plasma norepinephrine, or plasma epinephrine. The 10-min RAP value was inversely correlated with blood volume (r = -0.98, P < 0.01) and also with stroke volume (r = -0.96, P < 0.01). In the next 20 min of exercise, ANP continued to increase to 101 +/- 12 pg/ml (P < 0.02 vs. 10 min) and remained at this level until 50 min of exercise, whereas RAP decreased and reached a level not significantly different from baseline at 50 min (5.7 +/- 1.0 mmHg; P < 0.01 vs. 10 min). This dissociation of ANP and RAP may have been related to the significant increases from the 10-min values of heart rate, blood temperature, norepinephrine (all P < 0.01), and epinephrine (P < 0.02) during the same period. These results suggest that ANP release is primarily controlled by atrial distension at the onset of exercise but that other stimulators may be involved thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Egress route of emulsified 20 centistokes silicone oil from anterior chamber of rabbit.
Silicone oil is used in recent clinical practice, however, it may cause adverse reactions in the eyes. When the high viscosity silicone oil is contaminated with low molecular weight silicone oil, the contamination may cause ocular toxicity or elevation of the intraocular pressure. To obtain information on the distribution of this preparation, emulsified 20 centistokes silicone oil was injected into the anterior chamber of rabbit eyes. The silicone oil droplets were visualized by light and electron microscopy by using oil soluble phthalocyanine blue. This copper containing dye remains in the tissue after removal of the silicone oil by organic solvents. Two and 4 weeks after an injection, the silicone emulsion was observed as numerous small vacuoles with blue precipitate at the margin of vacuoles within elongated trabecular endothelial cells, fibroblasts along the route of uveoscleral outflow and cells of the iris. Three hours after the injection, only a few vacuoles were present in these cells. These results demonstrated that the emulsified silicone oil leaves the anterior chamber through the conventional and unconventional routes. Phagocytosis by the trabecular endothelial cells and fibroblasts along the uveoscleral route caused an accumulation of the emulsified silicone oil in these cells. With chronic exposure to emulsified silicone oil, changes in the trabecular meshwork may lead to a reduction in the outflow of aqueous humor and cause glaucoma.
Animals↗
Assessment of optic disc topography with scanning laser ophthalmoscope.
Evaluation of the topography of the optic disc is of clinical importance to assess the degree of nerve damage. We conducted a study in 17 glaucomatous and 20 control subjects with a scanning laser ophthalmoscope (SLO; Rodenstock) and compared the results with those in conventional photographs. A tomographic image of the cup area in control subjects and the neuroretinal rim area in glaucomatous subjects obtained with the SLO was smaller than that in photographs taken with a conventional camera (P < 0.05 and P < 0.01 respectively). In both the control and glaucoma groups, the optic disc area obtained with the SLO was significantly smaller than that in conventional photographs (P < 0.01). The coefficient of variation of the optic disc parameters studied with the SLO range from 4.2% to 9.1%. A correlation between the optic disc indices studied with SLO and the mean defect of the visual field was statistically significant. The tomographic images obtained by the SLO permit accurate assessment of optic nerve damage.
Fundus Oculi↗
Retinal nerve fiber layer defect as an early manifestation of diabetic retinopathy.
PURPOSE: An incidence of and risk factors for retinal nerve fiber layer defect were investigated in patients with type II diabetes mellitus and compared with that of age-matched control subjects. METHODS: The authors photographed the retinal nerve fiber layer of the right eye in each of 137 patients with diabetes and 144 healthy control subjects. The level of diabetic retinopathy ranged from levels 1 (no microaneurysm) to 4 (eyes with localized intra-retinal microvascular abnormalities or venous beading). Risk factors for the nerve fiber layer defect analyzed were age of patients, visual acuity, axial length, optic disc size, glycosylated hemoglobin, systolic blood pressure, and level of diabetic retinopathy. RESULTS: Defects of the retinal nerve fiber layer were found in 6/30 (20%) eyes with level 1 retinopathy, 8/14 (57%) eyes with level 2 retinopathy, 24/47 (51%) eyes with level 3 retinopathy, and 36/46 (78%) eyes with level 4 retinopathy. These defect incidences were significantly higher than that of the control group, which had 5/144 (3.5%) defects (P < or = 0.001). Risk factors for this nerve defect were level of diabetic retinopathy (P = 0.002), high systolic blood pressure (P = 0.0232), and patient's age (P = 0.0478). Not correlated with the incidence of the retinal nerve fiber layer defect were visual acuity, disc size, axial length, and glycosylated hemoglobin level at the time of examination. CONCLUSION: These findings suggest that the retinal nerve fiber layer defect is common in patients with early diabetic retinopathy. Risk factors for this defect were higher level of diabetic retinopathy, systemic hypertension, and advanced age.
Adult↗
Clinical features of neuroleptic malignant syndrome in basal ganglia disease. Spontaneous presentation in a patient with Hallervorden-Spatz disease in the absence of neuroleptic drugs.
Hallervorden-Spatz disease is a rare autosomal recessive disorder in which dopaminergic deficiency in the substantia nigra and its nigrostriatal projection has been identified. It is characterised by a slow but progressive course culminating in death. This case report describes a 13-year-old male, with a clinical diagnosis of Hallervorden-Spatz disease, who developed recurrent episodes of an acute illness, the features of which closely resembled those of the neuroleptic malignant syndrome. However, in this patient there had been no exposure to neuroleptic medication. The clinical events in this case suggest that dopaminergic hypoactivity, which is characteristic of Hallervorden-Spatz disease, can trigger episodes of neuroleptic malignant syndrome.
Acute Disease↗
A 3-year follow-up study of ocular hypertension by pattern electroretinogram.
A 3-year following-up study of the pattern electroretinogram (PERG) was performed in 15 eyes of 8 ocular hypertensive (OHT) patients. At first PERG recording, the amplitude of the first positive wave P1 was statistically significantly reduced in the OHT patients compared with age-matched controls (p < 0.05). There was no difference in the amplitude of the second negative wave N2 (p > 0.05). At 40 months, the amplitude of both P1 and N2 decreased and the latency of P1 was elongated. Among the changes, the decrease in N2 amplitude was the most drastic (p = 0.0001 compared with the control, p < 0.05, compared with the first recording). Glaucomatous visual field defects developed 5 years after the first PERG recording and 2 years after the reduction in N2 amplitude in 1 patient. Decreased N2 amplitude of the PERG may be an important warning sign predicting the development of glaucoma in OHT patients.
Adult↗
Trabeculotomy ab externo: an alternative treatment in adult patients with primary open-angle glaucoma.
Seventy-nine adult patients with primary open-angle glaucoma (POAG) were randomly assigned to treatment by modified trabeculotomy ab externo (TAB) (n = 44) and by trabeculectomy with adjunctive mitomycin C (TMC) (n = 35), and the postoperative outcomes achieved with these two techniques were compared. With TAB, the probability of successful intraocular pressure control 1 year postoperatively was .8644; with TMC, .8432; the difference is not significant (P = .7956). However, postoperative complications such as corneal epithelial damage, bleb leaks, hypotony, flat anterior chamber, and serous choroidal detachment were significantly less frequent in the TAB group. Largely because of this latter consideration, in selected cases, TAB may be a viable alternative to TMC.
Adult↗
Apparent cleavage of the retinal nerve fiber layer in asymptomatic eyes with high myopia.
The appearance of the retinal nerve fiber layer was studied in one eye of 203 normal Asians (59 with high myopia greater than or equal to -5 D, and 144 with emmetropia or hyperopia). "Cleavage" of the retinal nerve fiber layer was observed in 3 of these 59 highly myopic eyes, but there was no significant damage to either the retinal pigment epithelium or the choroid. In contrast, no cleavage was observed in the other 144 emmetropic or hyperopic eyes. High myopia (P = 0.0237, Fisher's exact test) was a significant risk factor for "cleavage" development in the retinal nerve fiber layer. The occurrence of a defect (nerve fiber loss) in the retinal nerve fiber layer in severe myopia (5/59, 8%) was also greater than that in either emmetropia or hyperopia (2/144, 1%; P = 0.0229). These results indicate that subtle changes can occur in the appearance of the retinal nerve fiber layer of the eye in some patients with asymptomatic myopia.
Adult↗
Multiple defects in the retinal nerve fiber layer in glaucoma.
We investigated the parameters that correlated with multiple defects in the retinal nerve fiber layer in 77 human eyes with normal-tension glaucoma, 110 with chronic high-tension glaucoma, and 102 control eyes. All 187 glaucomatous eyes had a nerve defect that was multiple in 20 cases. Correlation was significant between the multiple defect and the type of defect in the nerve fiber layer (P less than 0.002), size of the disc (P less than 0.02), and oblique insertion of the disc (P less than 0.02), as evaluated by the chi-square test. By multivariate analysis, refractive error was a high-ranking risk factor for multiple defect. Eyes with multiple defects tended to have moderate myopia, a focal nerve fiber layer defect and a small optic disc (category scores 0.0932, 0.0878 and 0.0697) and were less likely to have a diffuse defect in the nerve fiber layer, emmetropia or hyperopia, and a normal disc size (category scores -0.1077, -0.0705, and -0.548). The multiple defect in the retinal nerve fiber in glaucoma was frequently focal and correlated with myopia and a small optic disc.
Adult↗
Parameters associated with papillomacular bundle defects in glaucoma.
To evaluate the relationship between the papillomacular bundle defect and glaucoma types, abnormalities of the optic disc, distance between the disc and foveola, and axial length, we examined one eye of 82 patients with normal tension glaucoma, 117 patients with chronic high tension glaucoma, and 102 controls. Two types (diffuse and focal types) were found in the papillomacular bundle defect, and the former predominated. Eyes with a long axial length (P < 0.01), a diagnosis of normal tension glaucoma (P < 0.05), or a large optic disc (P < 0.05) tended to have diffuse-type papillomacular bundle defects, while eyes with a short axial length, a diagnosis of high tension glaucoma, or a large ovalness index are less likely to have it. Thus, a long axial length, a large optic disc, and normal tension glaucoma are risk factors for the diffuse-type papillomacular bundle defect.
Adolescent↗
Preservation of nerve fiber layer by retinal vessels in glaucoma.
The authors evaluated the correlation between various parameters and the local preservation of the retinal nerve fiber layer in 156 glaucomatous eyes. A vessel-associated preservation of the nerve fiber layer was observed in 45 of the 156 glaucomatous eyes. The presence of "straight" retinal vessels (either arterioles or large venules) and "tortuous" retinal vessels (large or small venules) inside of the scleral ring was correlated with the local preservation of the nerve fiber layer (P less than 0.001 and P less than 0.05, respectively). A local elevation of the floor of the cup was also correlated with the preservation of the nerve fiber layer (P less than 0.01). However, no correlation existed between either the preservation of the nerve fiber layer and the type of glaucoma, sex or age of patient, tilting of the disc, cilioretinal vessel, vertical cup-to-disc ratio, refractive error, disc size, distance between the disc and foveola, or the index of ovalness of the disc. These results suggest that retinal vessels in the disc significantly influence the vulnerability of the nerve fibers to glaucomatous damage.
Adult↗
Elevated mean systemic filling pressure due to intermittent positive-pressure ventilation.
To clarify the effect of intermittent positive-pressure ventilation (IPPV) on systemic circulation, mean systemic filling pressure (Psf) and circulating blood volume were measured together with other hemodynamic parameters of capacitance vessel. Change in circulating blood volume was determined by dilution with 51Cr-labeled erythrocytes. Vascular compliance (Cvas) was measured from the change in Psf caused by a bolus injection of blood. These parameters were measured during both spontaneous respiration and IPPV in male Wistar rats anesthetized with pentobarbital sodium. The shift from spontaneous respiration to IPPV reduced cardiac output (CO) by 20.9%. Psf increased significantly, from 7.1 +/- 1.2 to 8.6 +/- 1.1 mmHg. Central venous pressure (Pcv) also increased significantly. The pressure gradient for venous return decreased by 15.6% (from 6.4 to 5.4 mmHg). The resistance to venous return did not change significantly, but there was a significant increase in total peripheral resistance. Neither Cvas nor circulating blood volume was changed significantly by IPPV. These results indicate that during IPPV the increased Pcv attenuates the pressure gradient for venous return and decreases CO and that the compensatory increase in Psf is caused by a blood shift from unstressed to stressed blood volume.
Animals↗
Outcome of White pump shunt surgery for neovascular glaucoma in Asians.
We compared the effect of seton (White pump shunt) surgery (16 eyes) with that of trabeculectomy and 5-fluorouracil (31 eyes) in treating 38 Asian patients with medically uncontrollable neovascular glaucoma. We found the probability of long-term success (intraocular pressure < or = 26 > or = 5 mm Hg) of seton surgery (53.0% at 3 years) to be similar to that obtained following trabeculectomy with adjunctive 5-fluorouracil (45.4% at 3 years). However, 3 years postoperatively, the probability of the preservation of visual acuity was significantly greater following trabeculectomy than seton surgery (67.1% vs 23.1%; P < .05). In addition, the prevalence of postoperative complications was higher with the seton procedure (P < .001). The loss of endothelial cells 6 months postoperatively was more marked with seton surgery than with trabeculectomy, whether the shunt device touched the cornea (P < .000001) or not (P < .0005). In conclusion, White's pump shunt was effective in lowering the IOP of eyes with neovascular glaucoma. However, care must be taken to prevent postoperative complications, the incidence of which exceeded those observed following trabeculectomy with adjunctive 5-fluorouracil.
Adult↗
[Serum concentrations of ranitidine after intravenous administration in geriatric patients under general anesthesia].
The elimination rate of serum ranitidine was investigated in healthy geriatric patients under general anesthesia. The patients (50-90 y.o., ASA classification 1 and 2) were divided into Group 1 (age greater than or equal to 70, n = 9) and Group 2 (50 less than age less than 65, n = 6). Ranitidine (1 mg.kg-1) was administered intravenously after the induction of anesthesia, and the serum concentration was measured at 60 min and 120 min. The biological half life of serum ranitidine in Group 1 was 98.9 +/- 13.8 (M +/- SD) min, which was not significantly different from that of Group 2. The half life correlated with intraoperative urine volume (r = 0.62), but not with intraoperative bleeding or age. The duration of the above effective ranitidine concentration was calculated as about 4 and half hours after its i.v. injection. This indicates that additional administration is necessary for longer operations.
Aged↗
[Computerized monitoring system in the operating center with UNIX and X-window].
We previously reported the fully automated data logging system in the operating center. Presently, we revised the system using a highly integrated operating system, UNIX instead of OS/9. With this multi-task and multi-window (X-window) system, we could monitor all 12 rooms in the operating center at a time. The system in the operating center consists of 2 computers, SONY NEWS1450 (UNIX workstation) and Sord M223 (CP/M, data logger). On the bitmapped display of the workstation, using X-window, the data of all the operating rooms can be visualized. Furthermore, 2 other minicomputers (Fujitsu A50 in the conference room, and A60 in the ICU) and a workstation (Sun3-80 in the ICU) were connected with ethernet. With the remote login function (NFS), we could easily obtain the data during the operation from outside the operating center. This system works automatically and needs no routine maintenance.
Operating Room Information Systems↗