[Morphology and metabolism of otoconia of guinea pig].
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Biomedical subjects
N Tagashira
Publications and source records attributed to N Tagashira.
Three-dimensional structures of the vestibular sensory epithelia.
Vestibular neurosensory epithelia of the guinea pig and the bull frog were investigated by scanning electron microscopy. The crista ampullaris or macula were freeze fractured followed by maceration with 0.1% OsO4 solution for 24-60 h (osmium-DMSO-osmium method). Following this, three-dimensional intracellular structures were observed. The mitochondria which exist in the nerve chalice surrounding the type I cell were various in shape, globular, long and slender. Golgi apparatus, endoplasmic reticulum and thin fibrous structures of the sensory cells or supporting cells were clearly demonstrated. Concerning nervous system, nerve fibre, afferent and efferent nerve endings, further synaptic structures were also observed stereoscopically.
Acoustic Maculae↗
Electron-microscopic study of the vestibular dark cells in the crista ampullaris of the guinea pig.
The ultrastructure of the vestibular dark cells in the crista ampullaris of the guinea pig was observed using both transmission and scanning electron microscopy. The dark cells had numerous vacuoles of varying size and electron density, and also characteristic well-developed basal infoldings. These findings strongly suggest that the dark cells play an important role in fluid transport. Unique meshwork structures were observed on the luminal surface of the dark cells. Otoconia showing varying degree of degeneration were occasionally recognized on and near these structures. Electron microscopy revealed that the meshwork was comprised of cytoplasmic processes in a reticular arrangement. They seem to be engaged in the metabolism of otoconia, and perhaps also in fluid transport.
Animals↗
Three-dimensional observation of the spiral ganglion cell. Normal structure and pathological changes.
Spiral ganglia of guinea pig and mouse were investigated by scanning electron microscopy (SEM). The cochlea was freeze-fractured and then macerated with 0.1% OsO4 solution for 70-90 h (A-O-D-O method (1]. This allowed three-dimensional observation of the general view of the spiral ganglion and the intracellular structure. Two types of spiral ganglion cell, type I and type II, could be distinguished by the A-O-D-O method. Intracellular membranous structures such as mitochondria, endoplasmic reticulum (ER) and Golgi apparatus were also demonstrated stereoscopically. Furthermore, morphological changes in mouse spiral ganglion cells due to injection of Mycobacterium fortuitum were observed, using SEM. The degenerative process began as swelling of the mitochondria. When Schwann cell became affected, the myelin sheath disappeared and the ganglion cell border became indistinct. This degeneration developed rapidly, suggesting a direct influence of the bacteria on the ganglion cell. Various types of inclusion body with limiting membrane could be demonstrated stereoscopically. As Romand & Romand (4) suggested, these inclusion bodies may be remnants of cellular organellae or various type of lysosomes.
Animals↗
Three-dimensional observation of the cochlea. Intracellular structure of the hair cell and the supporting cell.
Intracellular structures of the guinea pig cochlea were observed by scanning electron-microscopy. The cochlea was freeze-fractured and then macerated with 0.1% OsO4 solution (aldehyde-osmium-DMSO-osmium (AODO) method). Intracellular organelles, such as mitochondria, endoplasmic reticulum (ER), and Golgi apparatus, were demonstrated stereoscopically. The ER of the outer hair cell showed the most interesting features, such as subsurface cisternae and lamellar body. The subsurface cisternae which formed a stratiform network covered the inner surface of the cell membrane of the supranuclear part. Variously shaped mitochondria were found on the innermost layer of the subsurface cisternae. The lamellar body consisted of dilated cisternae and tubules of ER. The tubular ER of the lamellar body were contiguous with the subsurface cisternae. The pillar cells, Deiters' cells and Hensen's cells had well-developed tubular ER, while Claudius' cells had poorly developed tubular ER.
Animals↗