PubMed Health⌕ Search

Biomedical subjects

J Tsutsui

Publications and source records attributed to J Tsutsui.

At least 19 recordsLinked to original sources
PubMed1992

Neuroethological evaluation of audiogenic seizures and audiogenic-like seizures induced by microinjection of bicuculline into the inferior colliculus. I. Effects of midcollicular knife cuts.

Audiogenic seizures (AS) are a model of generalized tonic-clonic seizures. The inferior colliculus (IC) and the GABAergic neurotransmission seems to be the most critical site and neurotransmitter system, respectively, of the auditory midbrain involved in AS origin and development. Thus, audiogenic-like seizures are evoked by GABAA antagonists such as bicuculline (BIC). Wistar audiogenic AS resistant (R) rats were sham-transected through the midcollicular line and microinjected with IC bicuculline (BIC; 80 ng/0.2 microliters) (n = 8); transected through the midcollicular line and microinjected with IC saline 0.9% (n = 8); transected through the cortex above the midcollicular line and microinjected with IC BIC (n = 3); transected through the midcollicular line up to 6.0 mm depth and microinjected with IC BIC (80 ng/0.2 microliters or 120 ng/0.3 microliters (n = 8). Wistar AS susceptible (S) rats were submitted to cortical transections (n = 8) and midcollicular transections (n = 7). Animals were studied by means of an ethological method before and after microinjections and/or transections in order to evaluate possible pathways in the AS-like evoked seizures. Bicuculline-evoked seizures were very similar to those evoked by acoustic stimulation, but lacked the tonic-clonic component. No modification in animal behavior was observed in the presence of sound, once the AS-like behavior was initiated. A small percentage of the animals, however, presented procursive behavior which was increased by sound. The IC BIC-evoked patterns were almost totally blocked by midcollicular but not cortical transections. Furthermore, midcollicular but not cortical transections blocked the tonic-clonic component of AS in genetically S animals without modifying the wild running component. These data suggest that the inferior colliculus-superior colliculus connection may be involved in the sensorimotor transduction necessary for AS-like behaviors.

Acoustic Stimulation↗
PubMed1992

Genomic structure of human midkine (MK), a retinoic acid-responsive growth/differentiation factor.

Midkine (MK) is a product of a retinoic acid-responsive gene and a new heparin-binding growth/differentiation factor. The coding sequence of human MK was located on 1.5 kb DNA segment. The structure of the cloned human MK gene was determined and compared with that of the mouse gene. The coding sequence was divided into 4 exons, and each exon and exon-intron boundary was highly homologous to those of the mouse. Furthermore, 170 bases in the upstream region of the putative transcription initiation sites and 3 blocks of 200-350 bases in regions further upstream were highly conserved. These sequences are likely to be involved in developmentally regulated expression of MK.

Animals↗
PubMed1992

Spectral analysis of electromyograms for extraocular muscles in normal and ophthalmoplegia cases.

Quantitative analysis of electromyograms (EMGs) of the extraocular muscles (EOMs), which contain fast fibers, like all skeletal muscles, but also slow fibers, was carried out in healthy subjects and a patient with external ophthalmoplegia. Interference EMGs of normal extraocular muscles demonstrated a relatively higher power spectrum in the higher frequency domain than those of the biceps brachii (BB). In the case of ophthalmoplegia, the lateral rectus (LR) and medial rectus (MR) muscles demonstrated a power spectrum with a wide ranging distribution up to 2,000 Hz in the early stage of recovery. Conservative treatment led to an improvement in the patient's ocular motility accompanied by a gradual shift of the spectrum towards lower frequencies within 265 days, during which time EMG examinations were performed four times. The results imply that the electrical activity of the slow fibers proper in the extraocular muscles affects the high frequency domain of the power spectrum and that the those fibers synchronously improve with fast fibers.

Action Potentials↗
PubMed1991

A new family of heparin-binding factors: strong conservation of midkine (MK) sequences between the human and the mouse.

A retinoic acid responsive gene, MK, specifies for a heparin binding factor termed midkine (MK), which is the initial member of a new protein family involved in regulation of growth and differentiation. A cDNA clone of human MK was isolated from a fetal kidney cDNA library. Human MK mRNA was expressed in PA1 teratocarcinoma cells as well as in the kidney. Sequence analysis of the cDNA clone and of a part of the genomic clone yielded the predicted protein sequence of human MK. Human and mouse MK sequences are highly conserved: 87% of amino acids are identical and all amino acid changes are conservative except for an insertion. Comparison of MK and HB-GAM/pleiotrophin (another member of the family) from various species revealed sequences conserved in the family and those specific for each protein.

Adult↗
PubMed1990

Objective visual acuity testing by optokinetic nystagmus suppression.

The features of optokinetic nystagmus (OKN) suppression were investigated in various kinds of visual disturbances including those of optical, retinal, higher cortical and psychogenic etiologies. A new OKN suppression device was developed, modifying the principle of Ohm. Objective visual acuities were calculated using the visual angle of OKN suppression dots which were arranged in 12 steps corresponding to the visual acuity from 0.03 to 1.0 as determined by Landolt's method. A total of 286 cases were tested. Results were classified into four types of coincidence between objective and subjective visual acuities. The first group showed equivalent acuities. Normal subjects, cases of corneal opacity, aphakia with intraocular lens implantation and functional amblyopia belonged to this category. In the second group, objective acuity could not be determined because of fixation disturbance due to cortical lesion. The subjective acuity better than the objective acuity was obtained in the third group which consisted of cases with macular hole, central serous retinopathy and optic neuritis with central scotoma. Disturbance of foveal fixation to the OKN suppression dot seemed to be the reason for this difference in the acuities. In the fourth group, the objective acuity was better than the subjective acuity. This occurred in cases of psychogenic visual disturbance and malingerer.

Adolescent↗
PubMed1990

[Delayed development of binocular function in the long postoperative period of infantile esotropia].

Long-term observation of binocular function was carried out in 30 postoperative cases of infantile esotropia. The period of observation was 5 to 12 years and the targets used for evaluation were deviating angle and stereo acuity. In the successful group, 20 cases out of 30 (67%) achieved a stereo acuity of 60 seconds or better. Among the remainder, partial improvement was seen in 20% and no improvement in 13%. Preexisting amblyopia and ARC improved in the successful group, and the final deviating angle was a mean of 2.3 prism diopter. There were 2 types of cure processes in the successful group. The first group achieved a good binocular function in a relatively early postoperative stage (7 cases), while the second group had delayed development of binocular function over a period of several years (13 cases). The former cases had sufficient orthoptic treatment during admission and the latter showed a gradual improvement of stereo acuity accompanied by good eye position. It has been generally accepted that the rate of binocular function recovery is very poor among cases of infantile esotropia, but our study revealed that skillful orthoptics administered by a selected member of our team over an extended period enabled the achievement of good binocular function in infantile esotropia.

Child↗
PubMed1990

Three-dimensional analysis of averaged electroretinograms for the evaluation of rhegmatogenous retinal detachment and related pathological conditions.

Retinal functional imaging in patients with rhegmatogenous retinal detachment and related pathological conditions was undertaken in 62 eyes of 44 cases by means of three-dimensional analysis (X-Y plane and time) of electroretinogram (ERG) topography. The analysis revealed that the area of maximal amplitude in both dominantly photopic and scotopic conditions deviated to the skin area closest to the location of the retinal detachment (hereafter referred to as paradoxical localization). In temporal retinal detachment, for example, the location of the maximal amplitude of the a- and b-waves deviated toward the temporal side on surface topography. Flicker ERG with a stimulus frequency of 30 Hz was especially successful for disclosing the existence and the location of posterior involvement of retinal detachment within the area surrounding the temporal vascular arcades. The mechanisms of paradoxical localization were considered to be changes in the axis of the equivalent dipole in detachment eyes. These abnormalities disappeared after the retina was reattached. Although the buckling procedure and argon laser retinopexy had little effect on the topographical distribution of the a- and b-waves, it was markedly distorted by cryoretinopexy. No remarkable changes in the topographical distribution of the waves were detected in pathological conditions predisposing to rhegmatogenous retinal detachment. This new method for functional imaging of the retina promises to be valuable for objective clinical evaluation of retinal detachment.

Adult↗
PubMed1990

Three-dimensional analysis of averaged electro-retinograms: normal appearance and bioelectric artifacts.

In 10 normal subjects, three-dimensional analysis (X-Y plane and time) was carried out of the dominantly photopic and scotopic components of the electroretinograms (ERG) for the purpose of functional imaging of the retina, after having evaluated bioelectric artifacts. The study of the artifacts had revealed that the major causes of distorting the topographical distribution were blinking, myogenic activities, eye movement, eye position and background activities of the electroencephalograms. In normal subjects, the maximal amplitude of the dominantly scotopic components was located around the lower eyelid, while that of the dominantly photopic components was situated around the upper eyelid. The mechanisms of the equivalent dipole axis of the dominantly photopic and scotopic components were different. However, similar changes in the equivalent dipole axes were found during the periods of eccentric eye positions. Similar topographical characteristics were noted in the latency mapping. The isopotential line of the dominantly scotopic components had a steep gradient and were suggestive of a superficial (peripheral retinal) origin, while that of the dominantly photopic components had a gradual gradient and seemed to be of deep (central retinal) origin. ERG topography would make functional imaging of the retina possible and would be of great diagnostic value.

Adult↗
PubMed1989

[Histopathological and clinical studies of acute necrotizing ulcerative gingivitis and evaluation of treatment].

We report the clinical data, light and electron microscopic findings, therapy and clinical course of three cases treated for acute necrotizing ulcerative gingivitis. The following results were obtained. 1. An ulcerous lesion was observed in the gingiva of all three cases, with case I also showing a depressed lesion in the ulcerous region. 2. In all three cases, the gingival sections displayed ulceration and showed fibrin deposition and neutrophil infiltration on the surface of the ulcerous region. Congested blood vessels and neutrophil infiltration also were observed in the connective tissue beneath the ulcerous region. 3. Many microorganisms, fibrin, cell debris, and enlarged intercellular spaces of the epithelium were seen on the surface on the ulcerous region. 4. Localized treatment, mainly plaque control, was found to be effective clinically and histopathologically.

Gingivitis, Necrotizing Ulcerative↗
PubMed1989

[Evaluation of typical and atypical retinal pigmentary dystrophy by three dimensional analysis (XY plane and time) of averaged electroretinograms].

Retinal functional imaging of patients with typical and atypical retinal pigmentary dystrophies was investigated by three dimensional (XY plane and time) analysis of ERG topography by comparing visual field and fluorescein angiographic findings. The three dimensional analysis revealed that the area of maximal amplitude deviated to the skin area closest to the dominant location of the retinal pigmentary dystrophy (the so-called paradoxical localization). In patients with temporoinferior sectorial retinal pigmentary dystrophy, for example, the maximal amplitude of the a-, b-waves and retinal oscillatory potentials deviated toward the temporoinferior side on the surface topography. These characteristic phenomena of a- and b-waves were found in 60.8% of all patients. Flicker topography with a stimulus frequency of 30 Hz was especially successful in showing the existence and location of paramacular involvement of retinal dystrophy within the area surrounding temporal vascular arcades. The detectability of macular asymmetric involvement was 65.2%. No significant topographic changes were detected in cases in the early stage with no remarkable visual field defects, or in the end stage with remarkable concentric field defects and complicated glaucomatous visual field defects. A comparative study of topographic changes, visual field changes and fluorescein angiographic findings showed that topographic changes in the a-, b-waves, retinal oscillatory potentials and 30Hz flicker components coincided more closely with visual field changes than fluorescein angiographic findings. We proposed that retinal pigmentary dystrophy is not a homogeneous lesion in its progression and believe that the ERG topography method can, by the imaging of dominant locations, detect this disease as well as visual field testing.

Adult↗
PubMed1989

[Three dimensional analysis (XY plane and time) of averaged electroretinograms for the evaluation of rhegmatogenous retinal detachment and related pathological conditions].

Retinal functional imaging in patients with rhegmatogenous retinal detachment and related pathological conditions was investigated by three dimensional analysis of ERG topography. The three dimensional analysis revealed that the area of maximal amplitude deviated to the skin area closest to the location of the retinal detachment (paradoxical localization). In temporal retinal detachment, for example, the maximal amplitude of the a- and b-waves deviated toward the temporal side on the surface topography. The depth of the retinal detachment was clearly indicated by differential ERG topography. Flicker ERG with a stimulus frequency of 30Hz was especially successful in showing the existence and location of macular detachment within the area surrounding the temporal vascular arcades. ERG topography also indicated the meridional extent of retinal detachment. When there was detachment in two quadrants (e.g., two inferior quadrants), deviation in the surface topography of a- and b-waves appeared in the same quadrants. When detachment expanded into three quadrants, deviation of the amplitude of a- and b-waves closely resembled the extent of the detachment. In addition, however, there was inverse a- and b-wave surface topography on the opposite skin area. When there were two quadrants of retinal detachment, there were two quadrants of inverse a-and b-waves. When there were three quadrants of retinal detachment, there was only one quadrant of inverse a- and b-waves. No inverse a- and b-waves were detected when there was only one quadrant of retinal detachment. In such cases, however, deviation in the surface topography covered three quadrants. These abnormalities were detected in 90.6% of all cases with the retinal detachment disappeared after the retina was reattached. While the buckling procedure and argon laser retinopexy had little effect on the topographical distribution, it was markedly distorted by cryoretinopexy. No remarkable changes in the topographical distribution of a- and b-waves were detected in pathological conditions related to rhegmatogenous retinal detachment. This new method for functional imaging of the retina should be valuable for objective clinical evaluation of retinal detachment.

Adult↗
PubMed1988

Short latency visual evoked potentials in functional amblyopia shown using moving topography.

The conduction from the eye to the visual cortex through the brainstem was investigated in 43 cases of functional amblyopia by means of moving topography of short latency visual evoked potential (SVEP). Anomaly of the SVEP such as a defect of the main component and remarkable reduction of amplitude was found in cases with severe amblyopia whose visual acuity was less than 0.5. The incidence of abnormal SVEP was recognized in 44% of anisometropic amblyopia (18 cases), 52% of strabismic amblyopia (15 cases), and 50% of deprivation amblyopia (10 cases). The results suggested a reduction of electric activity in the subcortical visual pathway including transmitting nuclei.

Adolescent↗
PubMed1987

Moving topography of human presaccadic spike potentials in visually triggered saccade and optokinetic nystagmus.

The spatio-temporal nature of presaccadic spike potentials (SP) associated with the visually evoked saccade and with the fast phase of optokinetic nystagmus was investigated by means of moving electroencephalographic topography. In both cases, SPs were recognized about 15-25 msec before the quick eye movements (peak time 3-7 msec). The amplitude of SPs was +5 to +7 microV for the visually guided saccade and +3.5 to +4.5 microV for optokinetic nystagmus. The location of the SPs was the mid-parieto-occipital region on the scalp, but their topographical character was that of a brainstem potential. In the case of the visually guided saccade, before the appearance of SP, an antecedent potential in the form of a slow positive charge appeared in the parietal region. From their spatio-temporal characteristics, the SPs investigated in this study were interpreted as mass potentials of the brainstem nuclei which generate eye movements.

Action Potentials↗