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Biomedical subjects

J Ito

Publications and source records attributed to J Ito.

At least 523 records · Page 29Linked to original sources
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Temporal bone pathology of a patient with cochlear implant.

A 66-year-old man with profound total deafness received a 22-channel cochlear implant. After surgery, his hearing improved and the postoperative course was uneventful except transient vertigo. The patient died of lung cancer after 2.5 years. Twelve hours after death, the temporal bone was harvested for histological and electron microscopic examination. The mastoid air cells were preserved, although a few mucosal folds were present. The Dacron mesh tie had largely been absorbed, but part remained embedded in fibrous tissue. No inflammation was noted in the tympanic cavity or the round window through which the electrodes were inserted. In the cochlea, the scala tympani was filled with fibrous tissue at the site of electrode insertion. The scala media had collapsed, while the organ of Corti and stria vascularis showed degeneration. Osseous spiral bundles and spiral ganglion cells were noted, though reduced in number.

Aged↗
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Electrophysiologic evidence for involvement of acetylcholine as a neurotransmitter in the lateral vestibular nucleus.

Monosynaptic spike generation of lateral vestibular nucleus (LVN) neurons with vestibular nerve stimulation in cats was inhibited by microiontophoretic atropine and gamma-aminobutyric acid (GABA). Spontaneous firing of the LVN monosynaptic neuron was increased by iontophoretic acetylcholine and glutamate. Atropine inhibited acetylcholine-induced firing without affecting glutamate-induced firing, while GABA blocked spike generation produced by acetylcholine and glutamate. Acetylcholine probably plays a role in transmission from the vestibular nerve to the LVN monosynaptic neurons.

Acetylcholine↗
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Computed tomographic findings of progressive supranuclear palsy compared with Parkinson's disease.

We investigated computed tomographic (CT) films of 4 pathologically documented cases of progressive supranuclear palsy (PSP) in which the clinical presentations were atypical and compared the findings with those of 15 patients with Parkinson's disease (PD). Dilatation of the third ventricle, atrophy of the midbrain tegmentum, and enlargement of the interpeduncular cistern toward the aqueduct were found to be the characteristic findings in PSP. Thus, radiological findings can be useful when the differential diagnosis between PSP and PD is clinically difficult.

Aged↗
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Inhibition of vestibular nerve activity by efferent fibres in the cat.

Electrophysiological studies were performed in anesthetized cats to examine the role of the parvocellular reticular nucleus (PCRN) in vestibular afferent fibers originating in the horizontal semicircular canal. When the primary afferent fibres intra-axonally recorded in the brainstem were classified into regular, intermediate, and irregular types, repetitive stimuli over 100 Hz applied to the PCRN inhibited spontaneous firing and the increase in firing during horizontal rotation in irregular and intermediate type units, whereas in regular type units PCRN stimulation affected neither the spontaneous firing nor rotation-induced responses. These results strongly suggest that the PCRN stimulation inhibits the primary afferent terminals of irregular type units receiving impulses from type I hair cells of the ampullae.

Animals↗
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Localization of motoneurons innervating the Eustachian tube muscles in cat.

The localizations of the motoneurons supplying the tensor tympani muscle (TTM), tensor veli palatini muscle (TVPM) and levator veli palatini muscle (LVPM) were determined by retrograde transport of horseradish peroxidase (HRP) in the cat. TTM motoneurons were found ipsilaterally outside the trigeminal motor nucleus in an area just ventral to it. TVPM motoneurons were distributed mainly in the ventral part of the ipsilateral trigeminal motor nucleus. They were more compactly distributed in the rostral part of the nucleus than in the caudal part. LVPM motoneurons were found in the ipsilateral nucleus ambiguus. There were no HRP-labelled cells in the contralateral nucleus ambiguus.

Animals↗
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The origin of autonomic nerves of the middle ear as studied by the horseradish peroxidase tracer method.

Autonomic innervation of the middle ear mucosa was investigated by the horseradish peroxidase retrograde tracing method. The middle ear mucosa was found to be sympathetically innervated by the fibres originating in the ipsilateral superior cervical ganglion, but not by those originating in the stellate ganglion. The middle ear mucosa was also innervated by the fibres originating in the ipsilateral pterygopalatine ganglion, suggesting this innervation to be parasympathetic.

Animals↗
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The origin of autonomic nerves of the Eustachian tube as studied by the horseradish peroxidase tracer method.

Autonomic innervation of the Eustachian tube mucosa was investigated by the horseradish peroxidase retrograde tracing method. The Eustachian tube mucosa was found to be sympathetically innervated by fibres originating in the ipsilateral superior and middle cervical ganglia, but not by those originating in the stellate ganglion. The Eustachian tube mucosa was also innervated by fibres originating in the pterygopalatine ganglion, but not by those originating in the otic ganglion. The innervation from the pterygopalatine ganglion was considered to be parasympathetic.

Animals↗
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Electrophysiological and HRP studies of the direct afferent inputs from the cochlear nuclei to the tensor tympani muscle motoneurons in the cat.

The direct fiber connections from the cochlear nuclei to the tensor tympani muscle (TTM) motoneurons were investigated by means of electrophysiological and horseradish peroxidase (HRP) methods, using cats. When HRP was injected into motoneuron region of the TTM, HRP-labelled cells were found bilaterally in the dorsal cochlear nucleus (DCN) and ventral cochlear nucleus (VCN). When the electrical stimulus was applied to the cochlear nucleus, the TTM motoneurons fired spikes monosynaptically with s short latency. These histological and electrophysiological results indicate the existence of direct fiber connections from the bilateral cochlear nuclei to the TTM motoneurons.

Animals↗
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Central fiber connections of the vestibulo-autonomic reflex arc in cats.

The fiber connections associated with the vestibulo-autonomic reflex in the brain stem were investigated in cats using electrophysiological and horseradish peroxidase (HRP) methods. When the peripheral labyrinth was stimulated, the stomach constricted, and in some cases this constriction was strong and lasted for a relatively long period. This phenomenon was interpreted as a kind of vomiting triggered by the vestibuloautonomic reflex. When the electrical stimulus was applied to the peripheral labyrinth, the solitary tractus nuclear (SN) neurons, where the vagal nerve cell bodies exist, fired spikes with short latencies. When HRP was injected into the SN region, HRP-labelled cells were found in the parvocellular reticular nucleus (PC) and vestibular nuclei (VN). When HRP was injected into the PC region, HRP-labelled cells were found in the VN. These electrophysiological and histological results indicate the existence of the following fiber connections: (i) vestibular organs-VN-SN-(vagal nerve)-stomach, (ii) vestibular organs-VN-PC-SN-(vagal nerve)-stomach, associated with the vestibulo-autonomic reflex.

Animals↗
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The influence of middle ear pressure on the vestibular nerve activity in cats.

The influence of middle ear pressure on the vestibular nerve activities was investigated in anesthetized cats. The vestibular nerve activities were recorded intraaxonally and positive or negative pressure was applied to the middle ear cavity through a tympanic membrane perforation. The firing of vestibular nerve fibers, especially the regular type nerve that responded to horizontal semicircular canal stimulation, increased with positive pressure and decreased with negative pressure. Most vestibular nerves that responded to anterior or posterior semicircular canal stimulation were not influenced by changes in the middle ear pressure. These results indicate that middle ear pressure load is transmitted to the vestibular end organs and then to vestibular nerve.

Action Potentials↗
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Somatosensory event-related potentials following different stimulus conditions.

We studied somatosensory event-related potentials (ERPs) in response to rare target, frequent nontarget and rare nontarget stimuli in 12 healthy subjects. Compared with the corresponding peaks following frequent stimuli, the responses elicited by rare target stimuli showed higher amplitudes for N70, P100 and N140 components and those evoked by rare nontarget stimuli showed higher amplitudes for N70 and N140 components. The P300 component following rare nontarget stimuli was shorter in latency and lower in amplitude than that elicited by target stimuli. ERP waveforms evoked by rare nontarget stimuli also showed obvious N240 and P300 components, which differed from those following frequent nontarget stimuli. These findings suggest that there are differences in signal processing in response to target, frequent nontarget and rare nontarget stimuli. The P300 component was distributed symmetrically and there was no significant hemispheric predominance with regard to any ERP component in response to either right or left side stimulation.

Adult↗
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Intellectual status of children with cerebral palsy after elementary education.

Using Wechsler Intelligence Tests, we compared the intellectual status of children with cerebral palsy (CP) immediately before and 2 years after entering school. Verbal and performance IQs could be assessed for 23 children with spastic diplegia but only verbal IQs in six children with spastic quadriplegia. Performance IQs were much lower than verbal IQs in both the Wechsler Preschool and Primary Scale of Intelligence (WPPSI) and the Wechsler Intelligence Scale for Children-Revised (WISC-R) in children with spastic diplegia. After schooling, verbal IQ was significantly increased but there was no change in performance IQ, thus, the difference between these IQs became more pronounced. When comparing the school class types, the verbal IQs of children studying in ordinary classes became statistically higher than those of children in special classes. In contrast, since the increases in mean performance IQs were greater in children in special classes, the differences between these IQs became more pronounced in children studying in ordinary classes. We also found that although verbal IQs were lower for quadriplegic children than for diplegic children at preschool age, there was no difference after 2 years of schooling. These results underline the importance and benefits of appropriate education for children with CP.

Analysis of Variance↗
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Influence of anti-allergic agents on in vivo expression of co-stimulatory molecules in normal mice.

The co-stimulatory signal provided by the interaction between CD28 and its ligands, CD80 and CD86, is critical for T cell activation. Engagement of CD40 and CD40L is also essential for IgE synthesis and secretion. In the present study, we examined the influence of anti-allergic drugs on co-stimulatory molecule (CD40, CD80 and CD86) expression in normal mouse splenocytes by flow cytometry. Treatment of BALB/c mice with azelastine (AZ) at a dose of 50.0 micrograms/kg/day, which is the most effective therapeutic dose, for two weeks scarcely affected the expression of co-stimulatory molecules CD40, CD80 and CD86 on splenocytes, whereas a three-week treatment strongly suppressed the expression of these molecules. We also examined the influence of terfenadine (TR) on co-stimulatory molecule expression. The expression of molecules on splenocytes was inhibited when donor mice were treated orally with 2.0 mg/kg/day of TR for three weeks. However, it was not inhibited during a two-week period treatment. These results suggest that the attenuating effects of anti-allergic agents on the diseases may be explained, in part, by their inhibitory action of co-stimulatory molecule expression.

Animals↗
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Suppressive effects of azelastine hydrochloride on CD40 expression in mice.

The present study was designed to examine the influence of an anti-allergic agent, azelastine hydrochloride (AZ) on a co-stimulatory molecule, CD40 expression in actively sensitized mice. BALB/c mice were sensitized by intraperitoneal injection of two doses of dinitrophenylated-ovalbumin and Al(OH)3 at one-week intervals. The mice were treated orally with 0.1 mg/kg of AZ once a day for 14 days starting the same day of booster sensitization. AZ treatment of mice caused the significant suppression of total serum IgE concentration on Day 21 after the first sensitization. However, AZ treatment scarcely affected IL-4 concentration in aqueous spleen extracts. Flowcytometric analysis revealed the suppressive effects of AZ on CD40 expression on sensitized-spleen cells. These data may suggest that AZ suppresses the production of IgE through the inhibition of CD40 expression.

Animals↗
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Symptomatic child case of subependymoma in the fourth ventricle without hydrocephalus.

We report a rare child case of symptomatic subependymoma in the fourth ventricle without hydrocephalus. The upper half of the tumor was demonstrated as a non-enhancing isodense mass with punctate calcification on CT, whereas the lower portion showed slightly irregular ring-like enhancement with a central hypodense area. The tumor was heterogeneously hyperintense on T2-weighted magnetic resonance (MR) images. When scanned with a T1-weighted sequence, the upper portion of the tumor was isointense to brain, but the lower portion was hypointense. However, using Gd-enhanced T1-weighted imaging, such as in postcontrast CT, the upper portion did not enhance, whereas the lower portion revealed similar ring-like enhancement, which was suggestive of necrosis. To further confirm the nature of the tumor, a diffusion-weighted imaging study with echo-planar technique was performed, and it indicated the solid nature of the tumor, which was confirmed histopathologically.

Brain Neoplasms↗
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Saccular aneurysm at the basilar artery fenestration.

The authors describe a 19-year-old patient who was presented with a subarachnoid hemorrhage and was found to have a saccular aneurysm arising at the proximal end of the fenestration of the basilar artery. Previously reported cases are reviewed. Stereoscopic magnification angiography facilitated the analysis of the three-dimensional-anatomical relationship between the aneurysm and its fenestrated parent artery.

Adult↗
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Use of MR angiography in a pregnant patient with thalamic AVM.

A 32-year-old pregnant woman at 29 gestational weeks suffered from the acute onset of severe headache. Brain CT, MRI, and MR angiography (MRA) showed intraventricular and thalamic hemorrhage, ruptured from a thalamic AVM. Based on these findings, conservative treatment was continued until delivery. After cesarean delivery at 34 gestational weeks, conventional cerebral angiography was performed, followed later by gamma-knife therapy. In pregnant patients with suspected cerebrovascular disorders, MRI and MRA should be the first of choice method to evaluate information on the diseased vessels and associated lesions since there is no radiation risk or side effects of contrast medium.

Adult↗