Search PubMed⌕ Search

Biomedical subjects

K Kawamoto

Publications and source records attributed to K Kawamoto.

At least 235 records · Page 13Linked to original sources
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

Cochlear potentials of guinea pigs with experimentally induced renal failure.

In order to investigate the relationship between renal failure and hearing loss, the authors made a guinea pig model with experimentally induced renal failure and examined cochlear potentials (N1, CM and EP). When renal damage was greater, the amplitudes of N1 and CM were decreased and the latency of N1 was prolonged, but EP was within normal range. The sensory cells of the cochlea were considered responsible for the hearing loss in the guinea pig model. No pathological alterations of the cochlea were revealed by a light microscopy. It is suggested that the etiology of the hearing loss was due mainly to metabolic disturbances such as uremic toxins, electrolyte imbalance or endocrine abnormalities.

Acute Kidney Injury↗
PubMed1987

Sound perception in the ultrasonic region.

The mechanism of ultrasonic perception was investigated electrocochleographically in guinea pigs (1) to compare AP responses in normal animals with those in kanamycin-poisoned animals with a damaged outer hair cell system; (2) and to analyse the masking property of continuous ultrasonic sound upon the AP evoked by burst stimuli within the auditory field. The study revealed several facts indicating the breakdown of cochlear sharp frequency analysis in the transduction of ultrasonic sound. We concluded that the sound perception in the ultrasonic region could be performed by the inner hair cell system without any enhancement or modulation of the outer hair cell system, which was regarded as an important process in a recent model of cochlear micromechanics.

Action Potentials↗
PubMed1987

Biological property of immune complex to prolong the duration of otitis media with effusion.

This study was designed to evaluate the biological properties of a light molecular weight immune complex, in comparison with that of a heavy molecular weight immune complex. Soluble immune complexes were obtained by mixing horseradish peroxidase (HRP) with guinea pig antiserum to HRP and were divided by gel filtration into several fractions according to their molecular weight (MW). After the chemotactic activity of each fraction was examined in vitro, the lightest and the heaviest MW immune complexes were injected into a guinea pig's left and right superior bulla, respectively. Although a middle ear effusion developed in both the bulla, the histopathological feature of an experimentally induced otitis media with effusion varied with the MW of the injected immune complex. The light MW immune complex proved to be a stronger inducer for a macrophage than the heavy MW immune complex, both in vitro and in vivo, and to have a tendency to persist longer in the tympanic cavity than the heavy MW immune complex. These results suggested that otitis media had a tendency to persist when a light MW immune complex was formed in a middle ear. The light MW immune complex was suspected to be involved in the pathogenesis of otitis media with effusion.

Animals↗
PubMed1987

Prognosis and endotoxin contents in middle ear effusions in cases after acute otitis media.

We analysed the endotoxin content of middle ear effusion (MEE) from patients after acute otitis media, by a Limulus assay. Endotoxin was positive in 70% of the cases treated with antibiotics at an acute event for more than 5 days, while the incidence of bacteria was only 22%. One month after the sample collection, cases with a high concentration of endotoxin in MEE still tended to have effusion. These results suggest that endotoxin in MEE cannot be easily inactivated and may be involved in the development of acute otitis media into chronic otitis media with effusions.

Acute Disease↗
PubMed1987

Ultrastructural pathology of the middle ear mucosa in otitis media with effusion.

To elucidate the histopathological features of the middle ear mucosa in otitis media with effusion (OME), 33 specimens were obtained from OME patients (28 from children and 5 from adults) at the time of the ventilation tube insertion, and examined by light- and electron-microscopy. The mucosa from both pediatric and adult OME patients with glue effusion consisted mostly of non-ciliated cells containing numerous low electron-dense granules with or without a core, and many macroapocrine sections were observed on the apical surface of the cells. The mucosa with mucoid effusion showed various secretory activity, but macroapocrine secretions were rarely found. The intercellular space was intact and the junctional complex was well preserved. In serous otitis cases, the epithelia consisted mostly of cuboid ciliated cells and non-ciliated cells without definite secretory activity. But the intercellular space became widened and the junctional complex was occasionally damaged, indicating that the epithelium was quite permeable. We concluded that there was no significant histopathological difference between the OME mucosa of children and that of adults, although the nature of the effusion was closely correlated with the morphological features of the epithelial linings.

Adult↗
PubMed1987

Topographic diagnosis of facial paralysis by the assay of lysozyme concentration in tears.

Lysozyme in tears is secreted from the main lacrimal gland innervated by a parasympathetic nerve via the greater petrosal nerve. Lysozyme activity in tears was analysed in 10 cases of unilateral facial paralysis due to the cerebellopontine angle (CPA) tumor and 10 normal cases. The lysozyme concentration in tears on the paralysed side collected by Schirmer No. 2 test was significantly lower than that on the healthy side, or bilateral sides of normal subjects. This decreased concentration on the paralysed side is due to the interruption of the reflex are at the level of CPA. It is concluded that our new method is more useful for topographical diagnosis of facial paralysis than is the conventional Schirmer's filter paper test.

Adult↗
PubMed1987

A case-control study of nasal cancers. An occupational survey.

A case-control study on the possible association between nasal cancers (NC) and occupations was undertaken for 107 male patients with nasal or paranasal cancer and 413 patients with other otorhinolaryngological disease (controls) admitted during the past 10 years to the Department of Otorhinolaryngology, Tohoku University Hospital. The controls were matched by sex, age, and time of admission. However, in the occupational groups surveyed, no evidence such as reported in England and other countries was obtained that could confirm the relationship between nasal/paranasal cancers and woodwork (especially furniture making). Although the relative risk of NC for farmers, foresters, carpenters and plasterers was found to be approximately 2, occupational exposure was hardly considered to be a likely cause. Instead, some common factors involved in the life style including dietary customs of people engaged in these occupations seemed to play a role in the increased relative risks.

Carcinoma, Squamous Cell↗
PubMed1987

[Treatment of craniofacial fractures].

In the facial fractures, a large number of these patients also sustain a head injury. Neurosurgical care should be the first choice when an intracranial injury is associated. In such situation, suitable timing of the reduction of the facial fractures would be often missed and this would result in functional disturbance and deformities of the face. The present report concerns the early definitive treatment of the extensive craniofacial fractures. Operative procedure and its result are presented. We have surgically treated 100 cases with facial fractures during the past 7 years. Sixty-nine percent of these cases were injured in traffic accidents. The most common site, accounting for 72%, was the middle third of the face. Open reductions and internal fixations were performed within 10 days following the injury in all cases. Among 100 cases, 28 had associated intracranial injuries. Most of these cases were accompanied with frontobasal or zygomatic fractures. Twenty-four cases underwent craniotomy for acute intracranial hematomas, brain contusions, CSF rhinorrhea or optic nerve injuries. In 21 out of 24 cases, primary reconstruction of the fracture were performed at the time of craniotomy. Whether a primary reconstruction was available or not was determined according to the patient's general condition and the severity of the associated intracranial injury. In the extensive frontobasal injury, it is of the utmost importance to have a water-tight dural closure. Fractures involving the sinus were treated by exenteration of the sinus without packing to establish the pathway to the nasal cavity.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents, Traffic↗
PubMed1986

Vasoactive intestinal peptide- and peptide histidine isoleucine amide-like immunoreactivity colocalize with vasopressin-like immunoreactivity in the canine hypothalamo-neurohypophysial neuronal system.

The distribution of vasoactive intestinal peptide (VIP) and peptide histidine isoleucine amide (PHI) was investigated in the canine hypothalamus by immunocytochemistry. VIP- and PHI-like immunoreactive neurons were detected in the magnocellular supraoptic and paraventricular nucleus. These magnocellular VIP- and PHI-producing neurons coexist with vasopressin-like immunoreactivity and send axons to the median eminence and neurohypophysis. These findings may serve as an anatomical basis for studying the function of VIP and PHI on pituitary hormone secretion.

Animals↗
PubMed1986

A case of primary amyloidosis confined to the small intestine.

A 60 year-old man with primary amyloidosis confined to the small intestine was reported. Multiple polyps of the small intestine were found by an upper GI series and enteroscopic polypectomy revealed massive deposition of amyloid in the lamina propria and the submucosa. No predisposing disorder or other sites of deposition were found, and the diagnosis of primary amyloidosis of the small intestine was confirmed.

Amyloidosis↗
PubMed1986

[Flow cytometric studies of brain tumors--5: New sensitivity test of antineoplastic agents for brain tumors and its clinical application].

Flow cytometry (FCM) has been used not only for the judgement of malignant tumor cells but also for the evaluation of chemotherapy. Recently, we established a new application of FCM for the choice of the best antineoplastic agent in the chemotherapy of brain tumor. At first, the system of sensitivity test was developed through the preliminary study using established brain tumor cell line. Antineoplastic agents were contacted with the cells in the monolayered culture and the cell viability and the changes of DNA-histogram were analyzed by FCM. The cell viability was measured with the staining of fluorescein diacetate, and DNA-histogram was analyzed by the staining of propidium iodide. The best agent was judged based on the changes of the cell viability and cell cycle. The cytocidal and cytostatic effects were evaluated quantitatively, showing coincidence with the sensitivity of the cells to the appropriate antineoplastic agent. Secondary, this system was applied for the 15 malignant tumor cases. In these cases, the best antineoplastic agent could be selected through this method. Present system will be applied for the clinical cases continuously. Sensitivity test by FCM could be established in vitro system, and will be of much value clinically.

Animals↗
PubMed1986

[Antineoplastic effects and mechanism of action of IFN-alpha on brain tumors with use of fluorescent isothiocyanate-labelled IFN].

The antineoplastic effects and mechanism of IFN-alpha with a newly designed fluorescent isothiocyanate-labelled IFN-alpha were studied on three established glioma-cell lines and cultured cells of clinical brain tumors. Viability, cell cycle and cells showing positive reaction with fluorescent isothiocyanate-labelled IFN were analyzed by flow cytometry. U373MG glioma cells in contact with 10(4) IU/ml of IFN for 24 hours had a dose dependency, decreased viability, S-phase block in the cell cycle and high rate of positive reaction with fluorescent isothiocyanate-labelled IFN. Two surgical cases, except for one case, showed similar results and other cell lines or meningiomas were not affected by IFN. As the antineoplastic effects of IFN-alpha correlated with the rate of occurrence of positive cells with fluorescent isothiocyanate-labelled IFN, sensitive tumor cells may have a respective specific receptor for IFN-alpha, and, therefore, fluorescent isothiocyanate-labelled IFN-alpha might be of clinical value with regard to the problem of the receptor as well as sensitivity test.

Adenoma↗