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This study explores factors determining axon calibres, using the normal cochlear nerve as a model. The topographic distribution of axon calibres in the cochlear nerve of the guinea pig was found to correspond to its known tonotopic organization. Axons derived from the cochlear apex which carry sounds of low pitch were located centrally in the nerve and were(More)
Wallerian degeneration was studied in the phrenic or sciatic nerves of mice following transplantation into Millipore diffusion chambers of 0.22 micron pore size which were implanted in the peritoneal cavity and kept for up to eight weeks. This method positively eliminates the access of nonresident cells to the tissue, at the same time providing proper(More)
The significance of internode length for sheath thickness was analyzed by electron microscopic morphometry in isolated internodes from the human roots C3 and S1. These populations differ in length but have similar caliber. The amount of myelin per internode was in linear relation with the product of axon circumference and the length of the ensheathed axon(More)
Counts of nuclei in electron micrographs of rat sciatic nerve show that approximately one third of the nuclear population is fibroblasts. Comparison of these figures with counts in teased fibers indicates that the majority of fibroblasts adheres tightly to myelinated nerve fibers. The early reactions and cellular transformations of the endoneurial(More)
(1) The length of the human ventral spinal roots in the newborn and in the adult were compared with the length of the internodes in these roots. Internodes of fibers of a given caliber were more than twice as long in the adult sacral roots than in the cervical roots. The factors of root elongation corresponded closely to the factors of internode elongation.(More)
The conditions under which frogs are kept prior to experimentation were found to have a measurable effect on peripheral nerve structure. Frogs kept for 12 weeks at 4 degree C had markedly shrunken sciatic nerve fibers compared with frogs kept at 19 degrees C. Intermediate fiber shrinkage was found for frogs kept at 19 degrees C without feeding. Counts of(More)
Unilateral hydrocephalus due to occlusion of one foramen of Monro was found incidentally at necropsy in a 52-year-old man. There was no evidence of a postinflammatory or neoplastic origin of the occlusion. Backward tilting of the diencephalon, asymmetric insertion of the septum pellucidum, lateral tilting of the fornices, and deformation of the hippocampal(More)
A method for the in situ fixation of human meninges for electron microscopic examination is described. It was found that the cranial meninges of humans do not include a subdural space. Instead there is a complex, tight layer of cells, the interface layer, composed in the innermost portion of the dura mater (the dural border cells) and the outermost portion(More)
The proximal stumps of five rat sciatic fibers, transected 72 hr earlier, were reconstructed on the basis of morphometry in subserial electron micrographs of isolated fibers. Three fibers showed extensive axon sprouting; 2 had no sprouts but were excessively swollen. The total volume of axoplasm in the axon swellings approximated the volume of axoplasm in(More)
The structure of macrocapillaries (also called 'sinusoids") in the outer membrane of chronic subdural hematomas was investigated by electron microscopy, with particular attention paid to vascular permeability. One characteristic of macrocapillaries is the frequent formation of gap junctions between adjacent endothelial cells. In endothelial gap junctions(More)