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Biomedical subjects

J Hozawa

Publications and source records attributed to J Hozawa.

At least 19 recordsLinked to original sources
PubMed1993

Immunocytochemical localization of substance P and neurofilament proteins in the guinea pig vestibular ganglion.

To examine the cytochemical features of primary vestibular afferent neurons, we examined the immunocytochemical distribution of substance P(SP) and neurofilament proteins (NFP) in the guinea pig vestibular endorgans and ganglion. 84.9% of vestibular ganglion cells showed SP-like immunoreactivity. SP immunoreactive cells were small in diameter (25.4 microns), and randomly distributed in the ganglia. NFP immunoreactive cells (34.2%) were relatively large in diameter (31.1 microns). By double-staining immunocytochemistry it was possible to distinguish three different cell types: SP-positive/NFP-negative, SP-negative/NFP-positive, and SP/NFP-positive vestibular ganglion cells. Vestibular ganglion cells can thus be classified on the basis of size and immunocytochemical characteristics. These chemically distinct subpopulations of vestibular ganglion cells may be an indication of functional differences within vestibular afferent neurons.

Animals↗
PubMed1992

Preprotachykinin A mRNA detected by in situ hybridization in guinea pig vestibular ganglion.

In situ hybridization histochemistry was conducted to examine the expression of mRNA encoding preprotachykinin A (PPTA), the precursor of the neuropeptide substance P (SP) and neurokinin A (NKA), in guinea pig vestibular ganglion. Signals for PPTA mRNA moderately accumulated on most ganglion cells. SP and NKA are thus confirmed to be present in vestibular ganglion cells of the guinea pig.

Animals↗
PubMed1992

Middle ear inflation with a gas mixture.

We studied the middle ear (ME) pressure in 13 atelectatic ears to evaluate the effect of politzerization or ME inflation by a catheter using both room air and a gas mixture. The gas contained 12% O2, 6% CO2 and 82% N2. Tympanometry was performed before and after the treatment. The elevated ME pressure induced by the treatments, whether with room air or the gas mixture, declined rapidly within the first 30 min. However, at 35 and 45 min after the treatment with room air, the mean decrease in pressure was significantly greater than with the gas mixture, which might be due to slow oxygen absorption through the ME mucosa.

Acoustic Impedance Tests↗
PubMed1991

Localization of substance P-like immunoreactivity in guinea pig vestibular endorgans and the vestibular ganglion.

The immunocytochemical distribution of substance P (SP) in guinea pig vestibular endorgans and the vestibular ganglion was investigated. Two kinds of SP-immunoreactive fibers were distinguished. Most were thick, and found around or beneath sensory hair cells. These SP-immunoreactive fibers were distributed predominantly on the slope of the crista and the peripheral region of the macula. By electron microscopy, we confirmed this type of SP-like immunoreactivity to be restricted within primary afferent neurons. Some vestibular ganglion cells also showed SP-like immunoreactivity, suggesting that SP is present in some primary afferent neurons, and is involved in afferent neurotransmission. The characteristic distribution of SP may indicate functional differences within each endorgan. The other group of immunoreactive nerve fibers, varicous thin fibers, could be found in the stroma of vestibular endorgans, nerve trunk, vestibular ganglion, and along blood vessels of the vestibular ganglion. These fibers may have a different origin, and have an influence on blood flow and certain other functions.

Animals↗
PubMed1991

The mechanism of irritative nystagmus and paralytic nystagmus. A histochemical study of the guinea pig's vestibular organ and an autoradiographic study of the vestibular nuclei.

To establish the difference of mechanism between irritative and paralytic nystagmus, alterations of Na-K-ATPase and succinic dehydrogenase activity in the vestibular sensorineural elements were investigated for 20 guinea pigs, and glucose uptake of the vestibular nuclei for 13 guinea pigs were measured by the [14C]-2-deoxy-D-glucose method. Irritative and paralytic nystagmus were experimentally provoked by introducing K+ into the perilymphatic space. From the results it was concluded that irritative nystagmus is provoked by increased excitability of vestibular sensory cells, while paralytic nystagmus is provoked by decreased excitability. However, the direction of nystagmus was eventually decided by the tonus imbalance between the bilateral vestibular nuclei. The ipsilateral vestibular nucleus was predominant during irritative nystagmus, while the contralateral vestibular nucleus was predominant during paralytic nystagmus.

Animals↗
PubMed1991

Coexistence of substance P and calcitonin gene-related peptide-like immunoreactivities in the rat vestibular endorgans.

The immunocytochemical distribution and coexistence of substance P (SP) and calcitonin gene-related peptide (CGRP) in the rat vestibular endorgans were investigated. SP-like immunoreactivity was found in nervous elements beneath and around hair cells. CGRP-like immunoreactivity was also abundantly distributed beneath and within the sensory epithelia. In the present study, double-staining immunocytochemistry revealed that three different types of immunoreactivities: SP-positive/CGRP-negative, SP-negative/CGRP-positive, and SP/CGRP-positive immunostaining can be distinguished. SP/CGRP-immunoreactive fibers were localized within as well as beneath the sensory epithelia. These fibers often penetrated the epithelia and nearly reached the surface. The present immunocytochemical evidence suggests that different types of peripheral nervous systems may exist in the vestibular periphery.

Animals↗
PubMed1991

Comparative study of computerized trapezoid rotation test and sinusoidal harmonic acceleration test.

By using the Contraves computerized rotary chair system, trapezoid rotation (TR) test and sinusoidal harmonic acceleration (SHA) test were performed on each subject on the same day. The results in 25 normal volunteers and 145 patients with peripheral vestibular disorders were as follows: 1) As regards directional preponderance, the results of two rotation tests agreed in 75.9% of all patients, but a discrepancy was found in the rest. Abnormality was detected by TR test in 57.2% of all patients, and, less frequently, in 45.5% by SHA test. 2) In normal subjects, the maximum slow phase velocity of nystagmus provoked by TR test was greater than that of nystagmus provoked by SHA test using angular acceleration of a magnitude comparable to that in TR test. 3) As to the detection of abnormal VOR gain, the results of two rotation tests agreed in 100% of patients with bilateral vestibular disorders. However, in patients with unilateral vestibular disorders, the detection rate was higher for SHA test than that for TR test.

Acceleration↗
PubMed1989

Immunocytochemical study of the GABA system in chicken vestibular endorgans and the vestibular ganglion.

The immunocytochemical distribution of gamma-aminobutyric acid (GABA), GABA synthesizing enzyme; L-glutamate decarboxylase (GAD) and degradative enzyme; GABA transaminase (GABA-T) in the chicken vestibular endorgans and the vestibular ganglion was investigated. GABA and GAD-like immunoreactivity were confined to the sensory hair cell cytoplasm, suggesting that GAD synthesizes GABA in the hair cell. GABA-T-like immunoreactivity, indicative of GABA degradation, was found around hair cells, along nerve fibers running through the stroma and within the ganglion cell. These immunocytochemical findings indicate that the GABAergic system exists in the chicken vestibular endorgans and that GABA may function as an afferent neurotransmitter at the level of hair cells.

4-Aminobutyrate Transaminase↗
PubMed1989

Chronic sinusitis and woodworking as risk factors for cancer of the maxillary sinus in northeast Japan.

In the period 1983 to 1985, 66 patients presented to six Japanese university hospitals with squamous cell carcinoma of the maxillary sinus. Using self-administered questionnaires, a case-control study was conducted to examine history of nasal diseases, occupational exposures, and other possible risk factors for this disease. For each patient, two controls were selected from the general population, matched to the patient by sex, age (+/- 5 years), and district of residence. A history of chronic sinusitis was associated with a 2.3-fold increase in risk (p = 0.05). A high relative risk was also observed in males with an occupational history of woodworking or joinery, particularly when these jobs involved sanding or lathing practices (RR = 7.5, p = 0.02). No association between cigarette smoking and maxillary sinus cancer was observed in this study and no evidence was found that indoor air pollution in the home is involved in cancer development.

Adult↗
PubMed1989

[Anatomical study of the superior jugular bulb by use of high-resolution computed tomography].

Using high-resolution computed tomography, the relationship between the superior jugular bulb and the tympanic cavity was analysed in 40 subjects. Until now, the superior jugular bulb was thought to lie below the floor of the hypotympanum, however, the following observations were made from this study: 1) In 48 (60%) out of 80 temporal bones (40 cases), the top of the superior jugular bulb was situated in the higher level than the floor of the hypotympanum. 2) In 9 cases, the jugular bulb was separated from the tympanic cavity by only thin bony wall. This finding was noticed on the right side in 8 cases and was bilateral in a case. 3) In 21 cases (52.5%), the right jugular bulb was situated in higher level than the left, and the reverse finding was noticed only in 4 cases (10.0%). The reason why the right jugular bulb is frequently higher than the left was thought to be related to its function. Namely, the jugular bulb is useful to absorb the pulsation of the carotid artery, therefore, it was considered that the anatomical and physiological differences between the right and left carotid arteries induce the asymmetry of the jugular bulbs.

Chronic Disease↗
PubMed1988

Immunocytochemical study of catecholaminergic innervation in the guinea pig cochlea.

The enzymes for synthesis of catecholamine, tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), and phenylethanolamine N-methyl transferase (PNMT), have been immunocytochemically localized in the guinea pig cochlea. Two groups of catecholamine-containing neurons could be distinguished. The first group, which was TH-positive/DBH, PNMT-negative, was found in the inner spiral bundle and the tunnel spiral bundle. The other group was TH, DBH-positive/PNMT-negative, and was found around the blood vessels. The immunocytochemical evidence obtained in this experiment suggests that the catecholamines should play a functional role in the guinea pig cochlea.

Animals↗
PubMed1988

[Effect of combined BCG and UFT therapy of human maxillary cancer transplanted into nude mice].

Twenty male 5-6 week-old nude mice transplanted with human maxillary cancer (MC-Ya) were divided into 4 groups. Group I was treated with oral administration of 0.2 ml of 0.9% saline solution daily for 10-30 days, and served as control. Group II was treated with oral administration of 1 mg/mouse of BCG once a week for 10-30 days. Group III was treated with oral administration of 15 mg/kg of UFT daily for 10-30 days. Group IV was treated with the combination therapy of BCG and UFT. In comparison of the treatment effects in 4 groups, following results were obtained: 1) Mouse immunosuppressive acidic protein in the sera of nude mouse elevated in all groups, especially in group III. 2) The inhibitory effect on the growth of tumor was observed in group III and IV, especially in group IV, but not in group II. 3) The reason why the growth-inhibitory effect was observed more remarkably in group IV than in group III, would be explainable as the immunosuppression by UFT was restored by the immunostimulating effect of BCG.

Administration, Oral↗
PubMed1987

Effect of high perilymphatic potassium concentration on the guinea pig vestibular sensory epithelium.

The 'rupture theory' has been proposed to explain the vertiginous attack of Meniere's disease, and the high perilymphatic potassium concentration was thought to be the most important factor in this theory. In this investigation, potassium ion was introduced through the round window into the perilymphatic space in guinea pigs by means of iontophoresis, to investigate the effect of high perilymphatic potassium concentrations on the vestibular sensory epithelium, histochemically. Following the iontophoretic procedure, spontaneous nystagmus was observed, directed toward the iontophoretic side (irritative nystagmus) for the first 10 min, and then toward the unaffected side (paralytic nystagmus) for 24 h. Both these nystagmus types were quite reversible and left no morphological change in sensory cells. However, histochemical analysis revealed an increased ATPase activity during the irritative nystagmus and decreased ATPase activity during the paralytic nystagmus in the synaptic area between the hair cells and the nerve endings of the vestibular sensory epithelium on the iontophoretic side. Judging by these results, high perilymphatic potassium concentration is assumed to affect the synaptic area of the sensory epithelium, leading to reversible nystagmus.

Animals↗
PubMed1987

The value of 'Trapezoid Rotation Test' by Contraves computerized rotary chair system.

Trapezoid Rotation Tests using the Contraves computerized rotary chair system were performed in 60 normal subjects and 213 patients with peripheral vestibular disorder. In normal subjects, directional preponderance was not observed. The so-called 'response decline phenomenon' by repeating the tests was not detected and the test results showed good reproducibility. On the other hand, the test results of patients were variable, in close relationship with the state of vertigo, and reflected patient's labyrinthine pathology so accurately that the inspection of the treatment course was possible by this testing system.

Evaluation Studies as Topic↗
PubMed1986

Experimental studies on mechanism of the Menière's attack: investigation into vestibulo-cochlear response of the guinea pig induced by potassium ion.

After introducing potassium ion through the round window into the perilymphatic space of 40 guinea pigs by means of iontophoresis, physiological and histochemical investigations were performed to determine the role of the high perilymphatic potassium concentration in the vertiginous attack of Ménière's disease. About 15 min after the iontophoretic procedure, electronystagmography revealed irritative nystagmus for the first 5 min and then paralytic nystagmus for the following 6 to 24 hr. Histochemical analysis of the vestibular sensory epithelia revealed the increased activity of succinic dehydrogenase and Na-K-ATPase during irritative nystagmus and the decreased activity during paralytic nystagmus. The Na-K-ATPase activity was dominant in the synaptic area between the hair cells and the nerve-endings of the vestibular sensory epithelia. There was some delay between the reversal of nystagmus-direction and the change of enzyme activity. This delay was thought to be produced by the central regulatory mechanism for the disturbed tonus-balance in the vestibular nucleus. On the other hand, electrocochleography revealed the decrease of the action potential without any initial irritative cochlear sign, and the enzyme activity of the cochlear sensory cells was decreased from the beginning.

Animals↗
PubMed1986

Validity of Ewald's law in the horizontal semicircular canals and the vestibular nuclei: electron microscopic observation and quantitative [14C]-2-deoxy-D-glucose study.

Two series of experiments were performed by using a total of 36 guinea pigs. The 1st series was to compare the influence of rotatostimulation on the bilateral cristae ampullare. After repeating the rotatostimulation with the cupulometric mode (the terminal turning velocity: 450 degrees/sec) for 48 hr, ultrastructural changes of sensory cells were found in 9 of 17 animals with transmission electron microscopy. They showed stronger influences on the ampullopetal flow side with the exception of one animal. In the 2nd series, the difference in excitability between the bilateral vestibular nuclei was investigated on 6 guinea pigs which were exposed to the clockwise constant angular acceleration of 1 degree/sec2 for 8 min. The autoradiographic study with [14C]-2-deoxy-D-glucose (the 2-DG) revealed that the rotation-induced glucose uptake was increased significantly in the superior and the medial vestibular nuclei of the ampulloptal flow side. The results of the two series of experiments suggest the predominance of the ampullopetal effect not only in the horizontal semicircular canals but also in the vestibular nuclei.

Animals↗