scholarly journals Electron Microscopy of Nerve Fibers V. On the Fine Structure of the Small Myelinated Nerve Fibers in the Peripheral Nerve

1962 ◽  
Vol 38 (5) ◽  
pp. 387-409 ◽  
Author(s):  
Ryohei Honjin ◽  
Akira Takahashi ◽  
Akira Nakamura ◽  
Hikaru Taniguchi
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Peripheral Nerve ◽  
Nerve Fibers ◽  
Myelinated Nerve ◽  
Myelinated Nerve Fibers

scholarly journals THE SUBMICROSCOPIC ORGANIZATION OF AXON MATERIAL ISOLATED FROM MYELIN NERVE FIBERS

1953 ◽  
Vol 98 (3) ◽  
pp. 269-276 ◽  
Author(s):  
E. De Robertis ◽  
C. M. Franchi
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Phase Contrast ◽  
Nerve Fibers ◽  
Myelinated Nerve ◽  
Myelinated Nerve Fibers ◽  
Dense Granules ◽  
Small Clusters ◽  
Membranous Material ◽  
The Way

A technique has been developed for the extrusion of axon material from myelinated nerve fibers. This material is then compressed and prepared for observation with the electron microscope. All the stages of preparation and purification of the axon material can be checked microscopically and in the present paper they are illustrated with phase contrast photomicrographs. Observation with the electron microscope of the compressed axons showed the presence of the following components: granules, fibrils, and a membranous material. Only the larger granules could be seen with the ordinary microscope. A considerable number of dense granules were observed. Of these the largest resemble typical mitochondria of 250 mµ by 900 mµ. In addition rows or small clusters of dense granules ranging in diameter from 250 to 90 mµ were present. In several specimens fragments of a membrane 120 to 140 A thick and intimately connected with the axon were found. The entire axon appeared to be constituted of a large bundle of parallel tightly packed fibrils among which the granules are interspersed. The fibrils are of indefinite length and generally smooth. They are rather labile structures, less resistant in the rat than in the toad nerve. They varied between 100 and 400 A in diameter and in some cases disintegrated into very fine filaments (less than 100 A thick). The significance is discussed of the submicroscopic structures revealed by electron microscopy of the material prepared in the way described.

scholarly journals THE ULTRASTRUCTURE OF ADULT VERTEBRATE PERIPHERAL MYELINATED NERVE FIBERS IN RELATION TO MYELINOGENESIS

1955 ◽  
Vol 1 (4) ◽  
pp. 271-278 ◽  
Author(s):  
J. David Robertson
Keyword(s):  
Electron Microscope ◽  
Schwann Cell ◽  
Cell Surface ◽  
Peripheral Nerve ◽  
Myelin Sheath ◽  
Nerve Fibers ◽  
Myelinated Nerve ◽  
Thin Sections ◽  
Double Membrane ◽  
Myelinated Nerve Fibers

Adult chameleon myelinated peripheral nerve fibers have been studied with the electron microscope in thin sections. The outer lamella of the myelin sheath has been found to be connected as a double membrane to the surface of the Schwann cell. The inner lamella is connected as a similar double membrane with the double axon-Schwann membrane. The relations of these double connecting membranes suggest that the layered myelin structure is composed of a double membrane which is closely wound about the axon as a helix. These findings support the new theory of myelinogenesis proposed recently by Geren. The possible significance of these results with respect to cell surface membranes and cytoplasmic double membranes is discussed.

Transitory traumatic paraplegia: electron microscopy of early alterations in myelinated nerve fibers

1972 ◽  
Vol 36 (4) ◽  
pp. 407-415 ◽  
Author(s):  
George J. Dohrmann ◽  
Franklin C. Wagner ◽  
Paul C. Bucy
Keyword(s):  
Electron Microscopy ◽  
Spinal Cord ◽  
White Matter ◽  
Nerve Fibers ◽  
Myelinated Nerve ◽  
Content Type ◽  
Myelinated Nerve Fibers ◽  
Myelin Sheaths ◽  
Fine Print

✓ The white matter of the monkey spinal cord was examined by electron microscopy during the first 4 hours following a contusion sufficient to produce a transitory paraplegia. At 5 min after injury the myelinated nerve fibers resembled those of the control animals. By 15 and 30 min after contusion, selected fibers were noted to have moderately enlarged periaxonal spaces. Attenuated myelin sheaths, splaying of the myelin lamellae, and a marked increase in the periaxonal spaces were present in affected nerve fibers at 1 hr following trauma. By 4 hrs after contusion approximately one-fourth of the fibers showed breakage of the myelin sheaths and consequent denuding of axons or marked attenuation of the myelin sheaths, greatly enlarged periaxonal spaces, and degeneration of the associated axons.

scholarly journals STUDIES ON THE PROBLEM OF PRESERVATION OF MYELIN SHEATH ULTRASTRUCTURE: EVALUATION OF FIXATION, DEHYDRATION, AND EMBEDDING TECHNIQUES

1961 ◽  
Vol 9 (2) ◽  
pp. 429-443 ◽  
Author(s):  
Richard M. Condie ◽  
A. Ervin Howell ◽  
Robert A. Good
Keyword(s):  
Electron Microscopy ◽  
Myelin Sheath ◽  
Nerve Fibers ◽  
Nerve Tissue ◽  
Tissue Preparation ◽  
Myelinated Nerve ◽  
Myelinated Nerve Fibers ◽  
Fixation Techniques ◽  
Myelinated Nerves ◽  
Embedding Methods

Currently accepted methods of tissue preparation for electron microscopy result in alterations of myelinated nerve fibers. In an attempt to minimize distortion of myelin, various fixation techniques, dehydration schedules, and embedding methods have been evaluated. It was found that the major damage to myelinated nerves occurs in the embedding procedure. A technique for embedding nerve tissue using the polyester Vestopal W is described which was found to result in improved preservation of myelin.

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