scholarly journals Acoustic Nerve Disorder NOS, CTCAE

2020 ◽  
Author(s):  
Keyword(s):  
Acoustic Nerve

On the vestibular labyrinth of Brachiosaurus brancai

2005 ◽  
Vol 15 (2) ◽  
pp. 65-71
Author(s):  
A.H. Clarke
Keyword(s):  
Body Mass ◽  
Cranial Nerves ◽  
Semicircular Canals ◽  
Upper Jurassic ◽  
Allometric Relationship ◽  
Vestibular Labyrinth ◽  
Extant Species ◽  
Acoustic Nerve ◽  
The Relationship ◽  
Photogrammetric Measurement

The extensive remains of large sauropods, excavated in the Upper Jurassic layers of the Tendaguru region of Tanzania, East Africa by Janensch [15], include an intact fossil cast of a vestibular labyrinth and an endocast of the large Brachiosaurus brancai. The approximately 150 million year old labyrinth cast demonstrates clearly a form and organisation congruent in detail to those of extant vertebrate species. Besides the near-orthogonal arrangement of semicircular canals (SCCs), the superior and inferior branches of the vestibulo-acoustic nerve, the endolymphatic duct, the oval and round windows, and the cochlea can be identified. The orientation of the labyrinth in the temporal bone is also equivalent to that of many extant vertebrates. Furthermore, the existence of the twelve cranial nerves can be identified from the endocast. The present study was initiated after the photogrammetric measurement of the skeleton volume of B. brancai [13] yielded a realistic estimate of body mass (74.42 metric tons). Dimensional analysis shows that body mass and average SCC dimensions of B. brancai generally fit with the allometric relationship found in previous studies of extant species. However, the anterior SCC is significantly larger than the allometric relationship would predict. This would indicate greater sensitivity, supporting the idea that the behavioural repertoire must have included much slower pitch movements of the head. These slower movements would most likely have involved flexion of the neck, rather than head pitching about the atlas joint. Pursuing the relationship between body mass and SCC dimensions further, the SCC frequency response is estimated by scaling up from the SCC dimensions of the rhesus monkey; this yields a range between 0.008–26 Hz, approximately one octave lower than for humans.

Laminin Promotes Differentiation, Adhesion and Proliferation of Cell Cultures Derived from Human Acoustic Nerve Schwannoma

1995 ◽  
Vol 115 (4) ◽  
pp. 517-521 ◽  
Author(s):  
Angelika M. Baur ◽  
Tobias I. Gamberger ◽  
Heiko G. Weerda ◽  
Mislav Gjuric ◽  
Ernst R. Tamm
Keyword(s):  
Cell Cultures ◽  
Acoustic Nerve

Physiological Basis of Cochlear Transduction and Sensitivity

1976 ◽  
Vol 85 (6) ◽  
pp. 697-710 ◽  
Author(s):  
Vicente Honrubia ◽  
David Strelioff ◽  
Stephan T. Sitko
Keyword(s):  
Hair Cells ◽  
Electrical Impedance ◽  
Cell Function ◽  
Nerve Fibers ◽  
Cochlear Function ◽  
Physiological Basis ◽  
Cochlear Potentials ◽  
Acoustic Nerve ◽  
Energy Dissipated ◽  
Line Organ

Experiments were conducted in the guinea pig cochlea and the Xenopus laevis lateral line organ to obtain information about the electrical impedance properties of the cochlea, the sources and characteristics of the cochlear potentials, and to determine if hair cells are electrically excitable. The significance of the resting and evoked cochlear potentials in the transduction process leading to excitation of the acoustic nerve fibers was evaluated by comparing the results of electrophysiological experiments with the prediction of a model of the cochlea designed after the mechanoelectric theory of hair cell function. The results of these experiments 1) were compatible with the prediction of the mechoelectric theory of cochlear function; 2) made it possible to estimate and compare the energy dissipated in generating and maintaining the cochlear potentials with the stores of biochemical energy available in the cochlea; and 3) showed that the hair cells are electrically excitable, from which it was concluded that interaction between the hair cells is feasible.

Lipochoristomas (Lipomatous Tumors) of the Acoustic Nerve

2003 ◽  
Vol 127 (11) ◽  
pp. 1475-1479 ◽  
Author(s):  
Sandy S. Wu ◽  
William W. M. Lo ◽  
Donald L. Tschirhart ◽  
William H. Slattery ◽  
Joseph N. Carberry ◽  
...  
Keyword(s):  
Cranial Nerve ◽  
Cerebellopontine Angle ◽  
Frozen Section ◽  
Fibrous Tissue ◽  
Clinical Manifestations ◽  
Clinicopathologic Features ◽  
Management Protocol ◽  
Acoustic Nerve ◽  
Cranial Nerve Viii ◽  
Internal Acoustic Canal

Abstract Context.—Lipochoristomas (lipomatous choristomas) are rare tumors of the acoustic nerve (cranial nerve VIII/vestibulocochlear nerve) within the internal acoustic canal and sometimes the cerebellopontine angle, and are histogenetically believed to be congenital malformations. Their clinically indolent behavior has recently prompted a more conservative management protocol in a quest for maximal nerve/hearing preservation. This approach contrasts sharply with that for the common internal acoustic canal/cerebellopontine angle tumors, the neuroepithelial neoplasms (acoustic schwannomas and meningiomas), which behave more aggressively and have more prominent clinical manifestations. Owing to their rarity, the clinicopathologic features of cranial nerve VIII lipochoristomas have been obtained mainly through case reports. Objective.—We present the clinicopathologic features of 11 cases of lipochoristomas of cranial nerve VIII. Design.—The 11 cases were documented between 1992 and 2003. We performed complete clinical reviews with histologic, histochemical, and immunohistochemical analyses of formalin-fixed, paraffin-embedded tumor samples. Results.—The patients were 8 men and 3 women with hearing loss of the right ear (5 patients) or the left ear (6 patients). No patient had bilateral tumors. All lipochoristomas histologically possessed mature adipose tissue admixed with varied amounts of mature fibrous tissue, tortuous thick-walled vessels, smooth muscle bundles, and skeletal muscle fibers, the latter verified with immunohistochemistry. Conclusions.—The histomorphologic and immunophenotypic evidence showed that these tumors are better characterized as choristomas than as simple “lipomas,” as they have been labeled in the past. Their overall nonaggressive clinical nature in addition to the characteristic radiologic and histomorphologic findings are important clinicopathologic features for the pathologist to recognize and differentiate, especially during frozen section evaluations, in order to direct the neurosurgeon to a more appropriate conservative therapeutic intervention.

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