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Biomedical subjects

E Chihara

Publications and source records attributed to E Chihara.

At least 37 records · Page 2Linked to original sources

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↗

Topographic changes in the optic disc in eyes with cotton-wool spots and primary open-angle glaucoma.

Changes in the topography of the optic disc in 26 eyes with cotton-wool spots displaying defects in the retinal nerve-fiber layer and in 31 eyes with early primary open-angle glaucoma showing a similar degree of such defects were studied by computer-assisted optic disc analyzer and then compared with 27 controls. Changes in the cup-to-disc ratio, cup volume, and ratio of rim area to disc area were not significant in eyes with cotton-wool spots. The quotient of cup volume divided by cup-to-disc ratio eyes with of primary open-angle glaucoma was greater than that in eyes with cotton-wool spots. For the detection of nerve loss in eyes with cotton-wool spots, the image analyzer, which identified the notches in the horizontally sectioned contour line of the cup, was more sensitive than stereoscopic detection of the notches in the rim (P less than 0.05). The image analyzer enabled the detection of slight nerve-fiber loss by examination of the contour line of the cup in eyes with cotton-wool spots.

Adult↗

Vascular viscoelasticity of perfused rat hindquarters.

To determine viscoelastic features of the rat hindquarters vasculature, we measured pressure-volume curves. Male Wistar rats were transected at the lumbar level, and the perfused hindquarters were oxygenated with a hollow fiber artificial lung. The blood volume was measured by counting 51Cr-labeled red cells led to a gamma counter through an extracorporeal circuit at a constant rate. With continuous monitoring of the venous pressure and circulating blood volume, saline was infused into the circuit from a venous branch for 5 min [1.2 +/- 0.3% (SD) of tissue weight] followed by a 10-min recovery phase. In the recovery phase, the venous pressure promptly declined to the preinfusion level, whereas the circulating blood volume decreased more slowly. This implied vascular stress relaxation of the hindquarters. Maxwell's viscoelastic model, consisting of a spring component and a viscous component, was applied to analyze the venous pressure-volume diagram. With a curve-fitting method, the calculated vascular compliance and relaxation time (a time constant of stress relaxation) were 1.31 +/- 0.14 ml.mmHg-1.kg-1 and 15.7 +/- 4.0 min (means +/- SE), respectively. The value of compliance of the hindquarters was smaller than those of visceral organs reported. In addition, the value for relaxation time suggests that the viscous response of the vasculature simultaneously overlaps change in blood volume due to extravascular fluid shift during the postinfusion period.

Animals↗

Atypical nerve fiber layer defects in high myopes with high-tension glaucoma.

The incidence of atypical optic nerve head and retinal nerve fiber layer defects was studied in 61 high myopic eyes (greater than or equal to -5 diopters) and 91 emmetropic or hyperopic eyes (0 to +3 diopters) of 152 patients with chronic high-tension glaucoma, and in 45 control myopic eyes (greater than or equal to -5 diopters). Horizontal ovalness or cyclotorsion, oblique insertion of the optic disc, and bean pot disc were more common in the high myopes. In the eyes with high myopia with glaucoma, inferior dominant nerve fiber layer defects, ectopic fiber defects, and multiple nerve fiber layer defects were common. The incidence of superior nerve fiber layer defects or superior-inferior equal nerve fiber layer defects was high in round or vertically oval discs and low in cyclotorted or horizontal oval discs. The oblique insertion of the discs correlated positively with a higher incidence of ectopic defects in high myopic eyes with glaucoma. The incidence of focal type nerve defects is higher in older patients and high myopes with oblique insertion of the optic disc. Atypical shape of the optic disc correlates positively with atypical retinal nerve fiber layer defects in eyes with high-tension glaucoma.

Adolescent↗

A comparative study of measurement of arterial blood pressure using HEM-802F and arterial cannulation.

Finger arterial blood pressures determined by a newly developed sphygmomanometer, HEM-802F, were compared with arterial pressure obtained from direct measurement of the radial artery. An excellent correlation was found between the two methods (systolic: r = 0.93, diastolic: r = 0.91), although there was a large variability among individual subjects. The range of differences between them are from +32 to -13 mmHg for systolic and +15 to -25 mmHg for diastolic blood pressure measurement. HEM-802F underestimated systolic pressure (-4.0 mmHg) and overestimated diastolic pressure (+6.7 mmHg), compared with intra-arterial readings. The HEM-802F was useful for the non-invasive arterial pressure monitoring during general anesthesia.

Journal Article↗

Effect of nicardipine hydrochloride on circulating blood volume and vascular compliance in dogs.

We studied the effect of nicardipine on the canine cardiovascular system, especially on total blood volume and vascular compliance. Under light halothane anesthesia, nicardipine decreased total blood volume significantly (from 80.0 +/- 8.4 ml/kg in the control state to 75.3 +/- 8.0 ml/kg under nicardipine administration, p less than 0.01), while it increased central circulating blood volume (from 17.1 +/- 5.9 ml/kg to 25.5 +/- 8.2 ml/kg, p less than 0.01), increased cardiac output and central venous pressure, and decreased mean arterial pressure (from 134.3 +/- 16.2 mmHg to 93.9 +/- 17.1 mmHg, p less than 0.01) and total peripheral resistance. Vascular compliance derived from fluid infusion experiments showed a significant decrease (from 8.9 +/- 3.8 ml/mmHg/kg to 5.5 +/- 8.0 ml/mmHg/kg, p less than 0.01). In addition to the vasodilatory action of nicardipine on arteries, these findings also suggest that 1) nicardipine causes a fluid shift from the vascular to the interstitial fluid space as a result of increased capillary pressure, 2) it increases preload through blood redistribution from the peripheral to the central circulation, and 3) it decreases compliance of the vessels, perhaps due to an indirect splanchnic venoconstriction.

Animals↗

Characterization of magnesium dependent adenosine 5'-triphosphatase in bovine brain cytoplasmic dynein.

The Mg2(+)-ATPase activity of cytoplasmic dynein isolated from bovine brain was examined in the absence of microtubules. Cytoplasmic dynein in the absence of microtubules showed Mg2(+)-ATPase activity with two distinct Km values, 272 microM and 11.8 microM. The initial burst of Pi liberation, which was due to occurrence of slow decomposition of reaction intermediate, was 0.67 mol per mol of cytoplasmic dynein. These results indicate that Mg2(+)-ATPase reaction of cytoplasmic dynein in the absence of microtubules is similar to that of flagellar and ciliary dyneins which have been shown not to hydrolyze ATP via a single pathway.

Animals↗

[A comparison of oral- and intramuscular-preoperative administration of ranitidine in children].

The effect of preoperative oral and intramuscular ranitidine administration on intragastric pH and volume was evaluated in children. Thirty healthy inpatients whose ages were 2-13 years, were randomly assigned to three groups. Twelve hours before the elective operation apple juice was given to the control group, and apple juice with 0.4 mg.kg-1 ranitidine to the second group (Oral group). For the third group (IM group) an intramuscular injection of 0.1 mg.kg-1 ranitidine was done. Intragastric pH was significantly elevated and gastric volume was also significantly reduced in IM group, and serum ranitidine concentration showed a high level of 359.4 +/- 85.6 ng.dl-1 (mean +/- SD). In oral group ranitidine effect on pH and volume was not significant, and the drug serum concentration was 31.6 +/- 13.3 ng.dl-1 which was slightly lower than the effective level. Though the intramuscular injection guaranteed safer gastric content, a painful injection is stressful for children. With the knowledge of elimination rate of serum ranitidine we recommend oral ranitidine (0.4 mg.kg-1) six hours preoperatively for pediatric premedication.

Administration, Oral↗