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Biomedical subjects

R Yuasa

Publications and source records attributed to R Yuasa.

At least 37 records · Page 2Linked to original sources
PubMed1988

A case of carcinoid tumor of the middle ear producing peptide hormones.

We report 6th case of carcinoid tumor of the middle ear in a 16-year-old man. The clinical, histologic, immunohistochemical and ultrastructural features are discussed. The tumor in the attic and the tympanic cavity was successfully excised by radical mastoidectomy. Microscopically, the argyrophilic property and neurosecretory granules which are characteristic of carcinoid tumor were found in the cytoplasm of tumor cells. Furthermore, peptide hormones were confirmed immunohistochemically in this case. This tumor should be considered in the differential diagnosis when biologically lowgrade tumor with glandular and trabecular architectures are encountered in the middle ear.

Adolescent↗
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

Sensation of aural fullness and its treatment with an autonomic nerve blocking agent.

One hundred and eighteen patients (143 ears) complaining of a full sensation in the ear without any evidence of other ear diseases were selected for treatment with an autonomic nerve blocking agent and were analysed clinically. Females were extremely predominant in number, 79% of the cases. Sixty-five of 143 ears (45.4%) showed normal hearing and 54 ears (37.8%) had sensorineural hearing loss in low tone. Four mg of butropium bromide, Coliopan, an anti-cholinergic routinely used as an antispastic agent, was injected intravenously. Subsequently, the aural fullness diminished or disappeared in 72.7% (104/143) and 33.5% (48/143) was dramatically relieved within 30 min after the injection. Sensorineural hearing loss in low tone which was recognized in 57 ears in this series also improved remarkably in 57.9% (33/57). These results suggest a close relationship between the autonomic nervous system, aural fullness and sensorineural hearing loss in low tone. According to this study, we recommend anti-cholinergics as the treatment for patients, especially for women, complaining chiefly of aural fullness but with normal otoscopic findings and normal tympanogram, and with or without sensorineural hearing loss in low tone.

Adolescent↗
PubMed1985

Endotoxin in middle ear effusions: in cases with persistent effusion after acute otitis media.

Endotoxin in persistent middle ear effusions (MEEs) from children with acute otitis media (AOM) whose acute inflammation had cleared was assayed by Limulus test, parallel with the detection of bacteria. Seventy-five percents of MEEs were endotoxin positive, and the concentration of endotoxin in MEE was not related to the interval between the onset of AOM and the date of sample collection. However, the cases with MEE that had high concentration of endotoxin tended to have persistent MEE for more than one month after sample collection. Therefore, the presence of endotoxin may be one of the causal factors of a delayed recovery of AOM and of the development of otitis media with effusion.

Acute Disease↗
PubMed1985

[Radiochemotherapy of head and neck cancers: dose reduction through the combination of cisplatin, bleomycin and tegafur].

Twenty-four cases of squamous cell carcinomas of the larynx and maxillary sinus were irradiated with or without cisplatin during a period from April 1973 through March 1984. Both bleomycin in oil and tegafur were administered irrespective of cisplatin. Therapeutic effectiveness was critically evaluated by means of serial biopsy and/or surgery. Radiotherapy alone could not bring about negative conversion of the biopsies, but ultimate negative conversion was observed in 18 out of the 24 cases when chemotherapeutics were appropriately combined. The five positives underwent surgery. In the cases of maxillary cancer, mixed infections appeared to interfere with the curative effectiveness of the radiochemotherapy. A resulting dosage reduction of 15Gy was observed in radiotherapy for negative conversion and one of 10mg for bleomycin as a result of incorporation of cisplatin.

Adult↗
PubMed1983

[Ototoxicity of micronomicin sulfate--audiometric assessment].

Micronomicin sulfate (MCR) is a new aminoglycoside antibiotic, and its antibacterial spectrum is similar to that of gentamicin (GM). According to the animal test, MCR has less ototoxicity than other aminoglycoside antibiotics such as GM. To check its clinical ototoxicity, MCR was given intramuscularly to 20 patients at dose of 120--240 mg/day, respectively for 2--8 days, and audiometry was carried out before and after administration of MCR. No evident change was detected between the preadministration hearing levels and the postadministration hearing levels. These data suggest that MCR is sufficiently safe in ototoxicity within dose of 120 mg/day for 4 days.

Adult↗
PubMed1980

Bone destruction due to the rupture of a cholesteatoma sac: a pathogenesis of bone destruction in aural-cholesteatoma.

Severe bone destruction in a cholesteatoma is one of the characteristic clinical features. To clarify the mechanism of bone destruction in cholesteatoma, the matrix of cholesteatoma and the attached bone, obtained during middle ear surgery, was observed by light microscope. Rupture of the epithelial lining in a cholesteatoma and the escaping contents (keratin), which gave rise to intense characteristic granulations in subepithelial tissue, were found. Furthermore bone destruction was always found at the site of subepithelial tissue of cholesteatoma. From these facts, the escape of contents from the sac of cholesteatoma into the subepithelial layer is considered to be an important factor in the mechanism of bone destruction.

Bone Resorption↗