Guinea pig and rat sciatic nerves were fixed with cacodylate-buffered aldehydes and OsO4, and were stained with ferric ion and ferrocyanide. Cytoplasmic surfaces of the non-myelinated nodal axon membrane of A-fibres display distinct electron-dense aggregates of stain. These aggregates were not observed in association with the paranodal or internodal axolemma. The membranes of C-fibres exhibit n...

In this paper, we consider a highly recursive interconnection network known as the fully connected cubic network (FCCN). By exploiting its recursive properties, we thoroughly analyze the performance of a simple routing algorithm for the FCCN. We show that at least 800 of the routes obtained from this simple algorithm are shortest paths, and this percentage increases further with the network siz...

Sural nerve biopsies from 13 patients with radiologically confirmed skeletal fluorosis were studied for myelinated fibre densities, frequency distribution of their diameters, and single teased nerve fibre preparations. It was observed that most of the biopsies showed a marked reduction in myelinated fibre densities with more than half of them involving the smaller fibres of less than 7 gm diame...

In the peripheral nerve trunks of vertebrates, the distance between the nodes of Ranvier is normally greater on fibres of larger diameter than on those of smaller size (Ranvier, 1875; Key and Retzius, 1876). At the time of myelination during development , internodal length is uniformly short, the nodes being spaced about 150 to 300 ,u apart. Each inter-node represents the territory of an indivi...

We have shown previously that ethylene, which accumulates in the air spaces of submerged stem sections of rice (Oryza sativa L. cv "Habiganj Aman II"), is involved in regulating the growth response caused by submergence. The role of gibberellins in the submergence response was studied using tetcyclacis (TCY), a new plant growth retardant, which inhibits gibberellin biosynthesis. Stem sections e...

Animal and plant cells compartmentalize to perform morphogenetic functions. Compartmentalization of myelin-forming Schwann cells may favor elongation of myelin segments to the size required for efficient conduction of nerve impulses. Compartments in myelinated fibers were described by Ramón y Cajal and depend on periaxin, mutated in the hereditary neuropathy Charcot-Marie-Tooth disease type 4F ...

Two experiments were conducted to characterize changes associated with ontogenetic aging in coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and to identify possible maturation "markers" for this species. In the first experiment (Experiment 1), scions of ages 1, 4 and 9 years were collected from four seed zones in field progeny tests and grafted onto 1-year-old rootstocks. In Experime...

Chronic cerebral hypoperfusion is a key mechanism associated with white matter disruption in cerebral vascular disease and dementia. In a mouse model relevant to studying cerebral vascular disease, we have previously shown that cerebral hypoperfusion disrupts axon-glial integrity and the distribution of key paranodal and internodal proteins in subcortical myelinated axons. This disruption of my...