Search PubMed⌕ Search

Biomedical subjects

H Shinkawa

Publications and source records attributed to H Shinkawa.

76 records · Page 5Linked to original sources
PubMedDate not supplied

Calbindin-D28K localization in the primate inner ear.

The distribution of one of the calcium-binding proteins, calbindin-D28K (CB-D28K), was studied in the adult human and squirrel monkey inner ear by means of immunocytochemical methods. Inner and outer hair cells in the organ of Corti and vestibular hair cells showed CB-D28K immunoreactivity, though some vestibular hair cells were devoid of immunoreactivity. In the spiral and vestibular ganglion, immunoreactive cells were found in both the squirrel monkey and human. The present results indicate that CB-D28K is localized within afferent neuronal components in these sensory organs and may regulate Ca++ levels for optimal neurotransmission in the primate auditory and vestibular systems. This study also provides evidence of two nonneuronal localizations of CB-D28K in the squirrel monkey. Subpopulations of fibrocytes in the spiral ligament and vestibular end organs were enriched with CB-D28K, suggesting that these cells are possibly equipped with the function to regulate Ca++ concentration in the perilymphatic fluid. In the maculae, many CB-D28K-immunoreactive particles were found in the otoconial membrane, indicating that CB-D28K may participate in the formation of otoconia.

Adolescent↗
PubMedDate not supplied

Histopathology of the inner ear in Usher's syndrome as observed by light and electron microscopy.

A case of Usher's syndrome, type 3, is described. Histologic study of the inner ear of the patient demonstrated hair cell loss in the basal turn, severe loss of spiral ganglion cells, widespread neural degeneration in the cochlea, and discrete collections of degenerating supporting cells in the organ of Corti. The pattern of neural degeneration bore some similarity to abnormalities in the retina in retinitis pigmentosa. However, the findings in the supporting cells had no obvious parallel to the findings in the retina in this disorder. The histopathology of Usher's syndrome has been equated with the Scheibe, or cochleosaccular, pattern of degeneration. However, the findings in the present case and a critical analysis of published data did not support this concept.

Cytoplasm↗
PubMedDate not supplied

Effect of diuretics on endolymphatic hydrops.

The effect of diuretics on endolymphatic hydrops, which was produced by obliteration of the endolymphatic duct and sac in guinea pigs, was determined by statistical analysis of volumetric changes in the scala media. When acetazolamide was administered orally at 159 to 434 mg/kg per day for a period of 30 days, endolymphatic hydrops did not reach the extent of distension shown in animal ears without drug treatment. No difference was seen in animals with one month of drug treatment followed by three additional months without treatment. This result suggests that acetazolamide has the effect of reducing endolymphatic hydrops only during the period of drug administration. On the other hand, there appeared to be no effect, statistically, on hydrops in animals which were treated with chlorthalidone 72 to 182 mg/kg every other day for one month with survival times varying from one to four months. The effect of this drug favorably reported for the treatment of Meniere's disease symptoms is not demonstrated on endolymphatic hydrops, but rather is likely to involve other mechanisms. There was no essential difference in the extent of cochlear sensory and neural atrophy in the inner ears of animals with or without these drug treatments.

Acetazolamide↗