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Biomedical subjects

T Fujikado

Publications and source records attributed to T Fujikado.

50 records · Page 3Linked to original sources
PubMed1995

Euthyroid Graves' disease showing no thyroid abnormalities except positive thyroid-stimulating antibody (TSAb): two case reports.

We report two cases of euthyroid Graves' disease in women who had ophthalmopathy without previous history of hyperthyroidism. Enlargement of extraocular muscles was observed by magnetic resonance imaging (MRI). The patients had no thyroid enlargement and their serum concentrations of free T4, free T3, and TSH were normal. The sera were negative for antithyroid microsomal and thyrogobulin antibodies, and anti-TSH receptor antibodies measured by radioreceptor assay. T3 suppression test results were normal. Only thyroid-stimulating antibody (TSAb) measured by sensitive bioassay was positive. These findings indicate that sensitive TSAb is the most useful laboratory test in the diagnosis of euthyroid Graves' disease.

Adult↗
PubMed1994

The effect of dopamine on the response to pattern stimulation--study of the chick ERG.

The effect of dopamine (DA) on the chick ERG was studied to evaluate its action on the on and off pathways and on the contrast mechanism with regard to background intensity. After intravitreal injection of DA, the b-wave, one component of the on response, was reduced with stimulus intensities lower than background intensity and enhanced with stimulus intensities that were higher. While the d-wave, one of the off responses, was enhanced with stimulus intensities higher than background intensity but not reduced with stimulus intensities that were lower. The pattern ERG amplitude was decreased at higher spatial frequencies. These results suggest that DA has different effects on the on and the off pathways as a function of the adaptive state and could affect the contrast mechanism.

Adaptation, Ocular↗
PubMed1994

Dural sinus thrombosis in Behçet's disease--a case report.

Sinus thrombosis, which causes pseudotumor cerebri, is difficult to diagnose with conventional imaging apparatus, CT and MRI. We report a case of sinus thrombosis due to Behçet's disease diagnosed by magnetic resonance angiography (MRA). A forty-five-year old man with severe headache and ocular pain was examined. Since he had a history of oral ulcers, genital ulcers, and erythema nodosum venous thrombosis, he had been diagnosed as having Behçet's disease previously. He showed marked papilledema bilaterally but no obvious intracranial lesion was observed by CT and MRI. On MRA, an obstruction was apparent at the sagittal sinus. Anticoagulant and steroid therapy were effective to relieve the headache, and to improve the constricted visual field temporarily. By MRA, blood flow was confirmed in the sagittal sinus. However, mild papilledema persisted and finally vision was lost because of optic atrophy.

Behcet Syndrome↗
PubMed1994

[Binocularity after treatment for constant exotropia].

We studied the binocularity of cured chronic exotropic patients and discussed the critical period of gross stereopsis and its vulnerability. An infant, developing chronic exotropia associated with myasthenia gravis at the age of 17 months, returned to exophoria 10 months later and showed a stereo-acuity of 800 sec. This clinical finding suggests that the critical period for gross stereopsis is before the age of 18 months and the function is recoverable even when it is suppressed for several months after that period. Of the 18 patients with chronic exotropia who had undergone surgery after school age. 16 patients (83.3%) recovered stereoacuity of 3,000 sec or better, which suggests that gross stereopsis once established will never vanish. Patients with chronic exotropia with poor central vision also recovered gross stereopsis and stable eye position after strabismus surgery, indicating that gross stereopsis with peripheral fusion is significant for the stabilization of the eye position.

Adolescent↗
PubMed1987

Saccadic eye movements evoked by microstimulation of lobule VII of the cerebellar vermis of macaque monkeys.

1. Oculomotor responses to microstimulation of the cerebellar vermis were studied on macaque monkeys by measuring eye position with a magnetic search-coil method. 2. Vermal microstimulation resulted in conjugate eye movements. Analyses of amplitude-velocity and amplitude-duration relationships revealed that although the peak velocities were slightly faster, the durations of these responses were comparable to those of spontaneous and visually guided saccadic eye movements (saccades). 3. Systematic mapping with microstimulation revealed that the low-threshold sites were localized in the white matter of a limited number of folia in the posterior vermis. The low-threshold region from which saccades could be evoked with stimulus intensities less than 10 microA was confined to lobule VII in seven monkeys; in the other five monkeys it included a posterior part of lobule VI (folium VIc). This region coincided with the distribution of saccade-related neural activity observed in the present study and corresponded to the vermal folia from which we previously recorded the burst mossy fibre units and the oculomotor Purkinje cell activity (Kase, Miller & Noda, 1980). 4. Microstimulation of most sites in the oculomotor vermis evoked saccades in oblique directions and the horizontal component of the saccade was always ipsilateral to the stimulation side. In penetrations through the paramedian vermis, the direction of the saccade changed gradually from upward oblique to downward oblique as the electrode was advanced vertically across lobule VII. The vertical component was dominant in these saccades. When the stimulation track was systematically shifted from the medial to the lateral part of the vermis, the horizontal component of the saccade increased and the vertical component decreased gradually until the saccade became almost horizontal. 5. The direction of saccades changed with the stimulus intensity; thus the topographical change in the direction of a saccade was consistent only when the stimulus intensity was adjusted to the threshold for every stimulus site. When stimulated with near threshold intensities, the evoked saccades were very seldom straight: the trajectories were curved in the responses observed at most vermal sites. The horizontal and vertical components of these saccades showed different onset latencies, durations, and peak-velocity latencies. Increasing the stimulus current produced differing effects on the two components of the saccades.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Involvement of Purkinje cells in evoking saccadic eye movements by microstimulation of the posterior cerebellar vermis of monkeys.

Neural mechanisms for evoking saccadic eye movements by microstimulation of the posterior vermis were investigated in monkeys trained to fixate a visual target. The low-threshold region from which saccadic eye movements could be evoked with currents less than 10 microA was confined to lobule VII in two monkeys and it included a posterior part of lobule VI (lobule VIc) in another monkey. The region from which saccade-related neural activity was recordable coincided with the low-threshold region. This region corresponded to the vermal lobules from which eye position and saccade-related Purkinje cells were recorded. Kainic acid (kainate) injected in the white matter of lobule VII resulted in severe losses of Purkinje cells within a radius of 1-2 mm of the injection site. The lesion tended to be larger toward the peripheral cerebellar cortices, which were connected to the injection site by natural courses of the afferent and efferent fibers. After the kainate administration, the distribution of saccade-related neural activity did not differ significantly from that of the preoperative mapping, in spite of the severe losses of cortical neurons. Burst discharges of mossy fibers were recordable in the white matter near the injection site, indicating that afferent fibers were relatively unaffected by kainate. After kainate administration, the saccadic eye movements could no longer be evoked by microstimulation applied to the posterior vermis. The stimulus sites from which saccades could be evoked after kainate administration were always associated with the presence of intact Purkinje cells. In such cases, the minimum current necessary to evoke saccades depended on the percentages of intact Purkinje cells spared. In the folia with normal Purkinje cell layers, the amplitude and direction of evoked saccades and the thresholds for evoking such eye movements were almost comparable to the preoperative data. Saccadic eye movements in response to microstimulation of the posterior vermis were caused by orthodromic impulses conveyed through the axons of the Purkinje cells. Insofar as the saccades elicited from lobule VII with currents less than 10 microA are concerned, antidromic activation of the afferent fibers is not the neural mechanisms subserving the oculomotor responses.

Animals↗
PubMed1987

Topography of the oculomotor area of the cerebellar vermis in macaques as determined by microstimulation.

1. Oculomotor responses to microstimulation of the cerebellar vermis of macaque monkeys were investigated by using a magnetic search-coil method. 2. The oculomotor responses were conjugate eye movements with an ipsilateral horizontal component. Analyses of amplitude-velocity and amplitude-duration relationships revealed that the peak eye velocities and the durations of the responses were comparable to those of saccadic eye movements. 3. Systematic mapping with microstimulation disclosed that the region in the cerebellar vermis that yielded saccades with weak stimulus currents was confined to lobule VII in five monkeys but included a part of folium VIc in the other four monkeys. This region coincided with the distribution of the saccade-related neural activity observed in the present study and also corresponded to the vermal folia from which we recorded the burst mossy-fiber units and the oculomotor Purkinje cell activity. 4. The oculomotor vermis was defined as that region of the cerebellar vermis that met the following criteria: 1) saccades were evoked with low-intensity microstimulation (with currents less than 10 microA); 2) vigorous saccade-related neural activity was present; and 3) Purkinje cell discharges were modulated with eye movements. The oculomotor vermis was more circumscribed and located more posteriorly than the vermal cortex explored in previous microstimulation experiments on monkeys. 5. Microstimulation of the oculomotor vermis evoked more or less curved saccades in oblique directions. The horizontal and vertical components were not simultaneous in some saccades: the shorter component started later or ended earlier than the other component and their peak velocities were not always synchronous. 6. The amplitude of the saccade depended on stimulus parameters; microstimulation with 10-12 pulses within a period of approximately 20 ms (500-600 Hz) was shown to be optimal. When the pulses were applied to the white matter or to the granular layer, a stimulus current of 10 microA was sufficient to evoke saccades. When the molecular layer was stimulated, evoked saccades were smaller and frequently curved, and an increase in the stimulus current changed either the initial direction or the trajectory of the saccade. 7. When the stimulus current was carefully controlled and maintained near the threshold, the direction of the saccade evoked from the oculomotor vermis was topographically organized.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMed1981

Two pathways from the facial skin to the superior colliculus in the rat.

In response to single shock stimulation of the facial skin, the field potential of two negative waves (N1 and N2) appear in the intermediate layers of the rat superior colliculus (SC). From the experiments of functional ablations of the cortical facial area, the N1 wave was ascribed to the post-synaptic activity mediated by the direct trigemino-tectal pathway whereas the N2 wave to that mediated by the trigemino-cortico-tectal pathway. Single unit recordings also confirmed the existence of two pathways from the facial skin to the intermediate layers of SC.

Animals↗
PubMed1980

Low frequency dielectric relaxation and light scattering under AC electric field of DNA solutions.

Low frequency dielectric relaxation of aqueous DNA was measured in a frequency range from 0.1 Hz to 30 kHz. Agreement was found between dielectric relaxation time and rotational one estimated from reduced viscosity for dilute solutions of DNA. The low frequency relaxation is thus ascribed to rotation of the major axis of DNA chains elongated by electrostatic repulsion between charges on the chain. A quasi-permanent dipole moment of DNA estimated from the dielectric increment is well explained by the fluctuation of dissociation of DNA. The above conclusion was confirmed for DNA samples of various molecular weights and for solutions in water ethanol mixtures. Effects of binding of salts and dyes are also interpreted in terms of the same mechanism. Light scattering of aqueous DNA under a.c. electric field supports the above conclusion.

Animals↗
PubMedDate not supplied

Use of dynamic and colored stereogram to measure stereopsis in strabismic patients.

The effectiveness of movement or color has not been well studied in assessing stereopsis in patients with strabismus. We developed a new stereotest equipped with both a monochromatic dynamic random dot stereogram (DRDS) and a static-colored stereogram (SCS) and examined the stereopsis of patients with strabismus. Three-dimensional (3D) images were displayed on a liquid crystal display equipped with a parallax barrier system, allowing 3D images to be seen independently by each eye without glasses. A DRDS with maximum disparity of 3200 seconds of arc was displayed having front-rear movement. An SCS displaying cartoon characters with disparities of 400 seconds of arc was also tested and compared with the Titmus stereotest. A total of 52 strabismic patients were tested. The DRDS showed a significantly higher (P = 0.02) detection rate of stereopsis (39/52, 75%) as compared with the Titmus fly test (28/52, 54%). The SCS did not show any difference in the stereopsis detection rate (24/521, 46%) when compared with the Titmus animal test (20/52, 38%). Thus, the DRDS was useful in detecting stereopsis in patients without stereopsis on the conventional Titmus fly test, while the SCS did not show any difference when compared with the Titmus animal test. The DRDS may examine a different aspect of stereopsis from the static stereopsis measured by the Titmus stereotest or SCS.

Adolescent↗
PubMedDate not supplied

Strabismus surgery using the intraoperative adjustable suture method under anesthesia with propofol.

PURPOSE: To evaluate the feasibility and efficacy of using the intraoperative adjustable suture method with anesthesia induced by intravenously administered propofol for strabismus surgery. METHODS: Seven adult patients (mean age, 29.7 +/- 18.5 years) with different types of strabismus were enrolled in this study. All patients underwent full ophthalmological and general medical examinations before surgery. Surgery was performed after induction of anesthesia using intravenously administered propofol that was titrated to control consciousness. RESULTS: Arousal of consciousness was observed at approximately 2 minutes after discontinuation of the propofol infusion in each case, and the consciousness level was sufficient to allow accurate cover-uncover testing and intraoperative adjustment of sutures. Minor complications of nausea in three patients and vomiting in one patient were noted after surgery. CONCLUSIONS: Strabismus surgery using the adjustable suture method with propofol intravenous anesthesia appears to be safe and useful for the treatment of adult strabismus.

Adult↗
PubMedDate not supplied

Effect of a nitric oxide synthase inhibitor on lens-induced myopia.

PURPOSE: It has still not been determined whether the retinal mechanism causing form-deprivation myopia (FDM) is different from that causing lens-induced myopia (LIM). We previously reported that FDM was blocked by an intravitreal injection of the nitric oxide (NO) synthase inhibitor, N-nitro-L-arginine methyl ester (L-NAME). In this study, we investigated the effect of L-NAME on LIM in chicks. METHOD: The left eyes of 6-day-old chicks were injected with 30 microl of nontoxic concentrations of L-NAME (< or = 360 mM) or saline. The right eyes were injected with 30 microl of saline. A -16 dpt lens was placed in front of the left eye for 6 days. Another group of 6 chicks were injected with 180 mM L-NAME (left eye) and with saline (right eye) before placing -16 dpt lenses in front of both eyes. After removing the lens, the refraction and the axial length were measured. The effect of L-NAME (180 mM) on the retina of a separate group of chicks was examined by electroretinography 60 min after an intravitreal injection in non-LIM-treated eyes. RESULTS: The eyes of chicks that were injected with 180 or 360 mM L-NAME were less myopic and had significantly shorter axial lengths than control eyes. A significant decrease of the On response and an increase of the Off response were observed. CONCLUSION: The injection of L-NAME into developing chick eyes that were then covered with a -16 dpt lens resulted in a modifications of retinal function and an inhibition of the development of myopia. These results, combined with the earlier findings, suggest that NO modulates a common retinal pathway that leads to both LIM and FDM.

Animals↗