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Biomedical subjects

T Morimitsu

Publications and source records attributed to T Morimitsu.

At least 73 records · Page 4Linked to original sources
PubMed1987

Computed tomographic evaluation of middle ear aeration following intact canal wall tympanoplasty.

The condition of the mastoidectomy cavity following intact canal wall tympanoplasty (ICWT) is always of great interest to the otosurgeon. We evaluated the status of postoperative aeration in a stable ear following ICWT for various types of chronic otitis media using high-resolution computed tomography (CT). The mastoidectomy cavity in all the cases of simple suppurative otitis is totally aerated and that in over 60% of the cases of adhesive otitis, attic type cholesteatoma and adhesive type cholesteatoma is obliterated by a soft tissue density mass. The size of aerated spaces in the postoperative middle ear cavity not only depends on the type of chronic otitis media but also tends to correlate with the degree of mastoid pneumatization in the opposite ear. CT is useful for the postoperative assessment of middle ear aeration.

Adolescent↗
PubMed1987

Effects of kanamycin sulfate on cochlear potentials and potassium ion permeability through the cochlear partitions.

The cochlear microphonics (CM), endocochlear potential (EP) and potassium ion activities in the endolymph and perilymph were measured in guinea pigs which received daily successive intramuscular injections of 500 mg/kg of body weight of kanamycin sulfate. Preyer's reflex threshold at 8 kHz began to increase after the 5th day of kanamycin treatment and disappeared on the 11th day. The maximum output of CM at 8 kHz began to decrease with a time course similar to Preyer's reflex. The potassium ion activities in the endolymph and perilymph and the EP did not change appreciably through all experimental days. The magnitude of the negative EP decreased in parallel with the reduction in CM and the relative potassium conductance (GK) between the endolymph and perilymph. These results lend support to the hypothesis that the site of production of the negative EP is probably in the hair cells and that the negative EP is mainly dependent on the permeability of the potassium ions in the organ of Corti.

Animals↗
PubMed1987

Mass stranding of Odontoceti caused by parasitogenic eighth cranial neuropathy.

Hearing organs of the Odontoceti from two mass strandings in 1983 and 1986 were examined histopathologically. In the 1983 stranding, two of three pilot whales (Globicephala macrorhynchus) were necropsied and numerous Nasitrema sp. were found close to the eighth cranial nerve (nervus vistibulo cochlearis) in both animals. Patchy degeneration of the eighth cranial nerve in and out of the modiolus of the cochlea was observed. In the 1986 stranding, five of 125 false killer whales (Pseudorca crassiclens) were examined and numerous trematodes (Nasitrema gondo) were found in the tympanic cavities. Severe degeneration of the eighth cranial nerve was discovered and there were many trematode eggs in the nervous and surrounding tissues. Parasitogenic eighth neuropathy is proposed again as the cause of mass stranding of the Odontoceti.

Animals↗
PubMed1986

Recurrent meningitis due to spontaneous cerebrospinal fluid otorrhea. A case report.

Bilateral congenital deafness was observed in a 9-year-old girl with recurrent meningitis. A careful workup, including polytomograph, CT scanning and Radioisotope (RI)-cisternography revealed an inner ear dysplasia of the Mondini type, viz. dilation of the lateral semicircular canal, vestibule and cystic degeneration of cochlea on both ears. RI-cisternography demonstrated an abnormal accumulation of radioisotope in the left mastoid region, suggesting spontaneous cerebrospinal fluid (CSF) otorrhea. At exploratory tympanotomy of the left ear, the CSF leak was found from a round defect in the center of the stapedial foot plate. The CSF leak was treated successfully by packing the vestibule with temporal fascia. Spontaneous CSF otorrhea is seldom the cause of meningitis but has to be considered especially if associated with a dead ear and with recurrent meningitis. The diagnosis and management are discussed.

Cerebrospinal Fluid Otorrhea↗
PubMed1985

Dissociation of the cochlear microphonics and endocochlear potential after injection of ethacrynic acid.

The cochlear microphonics (CM), endocochlear potential (EP) and summating potential (SP) were simultaneously recorded for 60 min after injection of 30 mg/kg body weight of ethacrynic acid. The EP decreased parallel with the CM for about 20 min after injection, but they differed in the recovery stage. Even when the EP was still negative, the output of CM for 500 Hz acoustic stimulus recovered to its original level and was supernormal. A large SP observed in the recovery stage of CM and EP seemed to suggest that some functional change in the hair cells might be connected with the supernormal CM. Four minutes of anoxia during the supernormal CM decreased CM to only 68% of its level prior to anoxia. A cathodal polarization of the scala media, to change the polarity of the dc potential gradient, reversed the polarity of CM in the anoxic guinea-pig cochlea but not in the guinea-pig cochlea administered ethacrynic acid. These results suggest that supernormal CM observed in this experiment may not be dependent on the dc potential gradient, but due to some functional change in the hair cells after the injection of ethacrynic acid, although CM is essentially dependent on the dc potential gradient between the scala media and the inside of the hair cells.

Acoustic Stimulation↗
PubMed1985

Laryngoplasty using suprahyoid muscles--hyoid transposition laryngoplasty.

A new technique of laryngoplasty using the function of the suprahyoid muscles (hyoid transposition laryngoplasty) was reported. Total laryngectomy is carried out as usual and the tracheal stump is anastomosed directly to the hypopharynx. The hyoid bone is cut medially, then transpositioned and sutured to the posterolateral margins of the tracheal stump. With this procedure, the new glottis is pressed strongly to the tongue base during swallowing and aspiration is avoided. Postoperative swallowing and speech in the cases operated on with this method were satisfactory, and even nasal respiration was possible in some cases.

Aged↗
PubMed1983

Surface view of strial vessel, prominence vessel, and external sulcus cells as revealed by scanning electron microscopy.

The stria vascularis and the spiral prominence in the lateral cochlear wall were observed with scanning electron microscopy (SEM) after dissolving out the epithelial layer and the basement membrane by tryptic digestion and HCl hydrolysis. The external sulcus cells have regularly arranged pegs and a fine basal interdigitation on the cell surface. The strial vessel and the spiral prominence vessel could be visualized well and the characteristic surface view of their periendothelial cells presented. The former has cytoplasmic processes with a fine branching appearance similar to red coral and the latter has bulged popcorn like processes. Their functional significance is discussed.

Animals↗
PubMed1982

Fibrinolysis-coagulation system in patients with cancer of the head and neck. Preliminary report.

Five parameters of blood coagulation and fibrinolysis, viz., levels of fibrinogen, fibrinolytic activity of euglobulin, fibrinogen and/or fibrin-degradation products (FDP), antiplasmin activity, and antithrombin activity, were measured in patients with cancer of the head and neck, and the results were compared with those of healthy adults. The fibrinogen content in cancer was significantly increased (p less than 0.001), the fibrinolytic activity of euglobulin significantly enhanced (p less than 0.001), the antiplasmin activity significantly reduced (p less than 0.05), the antithrombin activity significantly reduced (p less than 0.001), and the FDP level slightly increased, although the difference was not significant. The importance of the coagulation and fibrinolytic system in cancer of the head and neck is discussed.

Adult↗
PubMed1981

Differences in physicochemical properties between tissue plasminogen activators from human paranasal mucous membrane and pig heart.

In order to clarify the physicochemical property of tissue plasminogen activator (TA), tissue extracts of human paranasal mucous membrane and pig heart were studied by the biochemical techniques. The studies by gel filtration revealed that two plasminogen activators of different molecular weight were present in the extract of human paranasal mucous membrane. The existence of tissue plasminogen activator with a low molecular weight (LMW-TA) has not previously been reported. This molecular weight of this compound was lower than that of cytochrome c. On the other hand, the molecular weight of tissue plasminogen activator from pig heart (PH-TA) was similar to that of ovalbumin, about 46,000 daltons, as estimated by Sephadex G-150 gel filtration. From the physicochemical property of LMW-TA, it is suggested that the LMW-TA from paranasal mucous membrane with chronic sinusitis was produced by proteases, i.e. trypsin-like enzyme, present in the mucous membrane with chronic inflammation.

Animals↗