The ultrastructural pattern of the acoustic nerve Schwannoma was studied on surgically excised tumours and on explants cultured in vitro. The typical neoplastic cell is elongated, spindle-shaped, coated with basement membrane and numerous protruding cellular processes. Cells demonstrating numerous microfilaments are also seen, sometimes intermixed with the typical spindle-shaped cells. Fibroblasts are not uncommon; nor are cells with a round nucleus and rich in organelle cytoplasm, resembling endothelial cells. Numerous collagen fibres and "Luse bodies" are seen in the extracellular space, especially in areas of low cellularity. Round or ovoid cells partially coated with basement membrane are not uncommonly seen in various areas of the neoplasm. In culture, several cells demonstrate fibrillary cytoplasm and long thin cellular processes are frequently seen. Unusual features, such as enwrapping of the cytoplasmic processes forming laminated myelin-like figures are occasionally seen in the surgical specimens as well as in the in vitro cultured explants.

Cells, Cultured↗

PubMedDate not supplied

Substance P in the acoustic area of the cortex during neuronal development and maturation.

Substance P has been proved an important neurotransmitter and neuromodulator, serving not only as an excitatory transmitter of the first afferent synapse of pain pathways but as a valuable neuromodulator in the primary cortical areas of sensosensorial integration. In the human acoustic cortex, substance P has been found in the presynaptic terminals as well as in the cell bodies of numerous polyhedral, triangular and bipolar neurons. Using histochemical techniques, we found recently that substance P is first accumulated in the neuronal elements of the human acoustic cortex in 18-gestational-week (GW) fetuses. Most of substance P is distributed in the neurons of the 3rd and 4th cortical layers, mainly in the cell bodies, the initial part of the axons and the axonic terminals. In 24-GW fetuses, substance P is found in the 2nd cortical area inside the cell body of the granular and bipolar neurons. In 28-GW fetuses, substance P is found in the pre- and postsynaptic terminals. We would suggest that substance P is accumulated increasingly as a function of the neuronal maturity of the primary acoustic cortical area, serving mainly as a neuromodulator.

Auditory Cortex↗

PubMedDate not supplied

The neuropeptides in the acoustic cortex. I. Substance P.

Peptides are the most recently studied chemical category of neurotransmitters. Most of them are found located in special diencephalic neurons and in some cortical areas serving as transmitters for specific synaptic junctions. In the human acoustic cortex we tried to identify substance P which may participate in the synaptic transmission at the various morphological types of synapses.

Adult↗

PubMedDate not supplied

[Congenital dysplasia of the middle ear. Satisfactory results of homotransplants of tympanic membrane and the ossicular system].

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Ear Ossicles↗