Fixation of the Central Nervous System by Perfusion With Aldehydes and its Effect on the Extracellular Space as seen by Electron Microscopy

1967 ◽  
Vol 2 (3) ◽  
pp. 377-386
Author(s):  
PATRICIA V. JOHNSTON ◽  
BETTY I. ROOTS

Rat brains fixed by perfusion with glutaraldehyde and prepared for electron microscopy under certain conditions showed an abundance of very closely apposed or completely fused surface membranes in some areas. This apparent lack of extracellular space was most consistently observed in the lateral geniculate body and the superior colliculus and less consistently in the cerebellum and parietal cortex. Lowering the temperature of the perfusate from body temperature (38-39 °C) to room temperature (19-20 °C) and/or lowering the pressure at which it was delivered (from 140 to 70 cm of water) led to the appearance of more extracellular space. A striking change in the amount of extracellular space was observed when ethanol was used for dehydrating the samples instead of acetone. When ethanol was employed a space of approximately 100 Å was seen between most cellular elements, whereas acetone dehydration led to an abundance of closely apposed or fused surface membranes. It is suggested that if glutaraldehyde acts by cross-linking proteins in apposing membranes, this reaction is more effectively completed in the presence of acetone and that this may be due to depolymerization of glutaraldehyde by the solvent. It is also suggested that the variation in the amount of extracellular space seen in brains fixed by perfusion with aldehydes may reflect real differences in distances between membranes at the time of fixation.

1995 ◽  
Vol 37 (2) ◽  
pp. 137-143
Author(s):  
C.L.P. Lancellotti ◽  
C.E.P. Corbett ◽  
M.I.S. Duarte

Histopathological and ultrastructural studies of 23 patients who died with clinical diagnosis of measles were carried out. In 12 cases viral nucleocapsids were searched by electron microscopy and detected in 100% of the cases in the lungs and in 50% of the cases in the central nervous system. They were mostly intranuclear. Histopathological changes associated to neurological alterations and the detection of virion are discussed in relation to acute and delayed clinical manifestations.


Author(s):  
P.H. Mortimer

This paper briefly introduces animal disease aspects of ryegrass staggers IFiGS) and describes the occurence and the clinical signs of the disease. Recent suggestions for the production of a reversible biochemical lesion in the central nervous system are mentioned in relation to the apparent lack of specific morphological lesions found in sheep. The recent isolation of novel potent neurotoxins, the lolitrems, from toxic pasture material is reviewed. There is now strong circumstantial evidence that the lolitrems produce the neurotoxic disease of RGS and also that the lolitrems are elaborated in the close association of perennial ryegrass with its parasitic fungus, Lolium endophyte, in pastures. Under what conditions the lolitrems are produced, or their precise locus within the association, are not yet known.


1968 ◽  
Vol 5 (1) ◽  
pp. 67-74 ◽  
Author(s):  
W. Kay Read ◽  
Charles H. Bridges

Spontaneous lipidosis of the central nervous system of two Yorkshire swine is reported. The presence of membranous cytoplasmic neuronal inclusions similar to those reported in Tay-Sach's disease in man was confirmed by electron microscopy.


2015 ◽  
Vol 26 (5) ◽  
pp. 489-506 ◽  
Author(s):  
Manuela Marcoli ◽  
Luigi F. Agnati ◽  
Francesco Benedetti ◽  
Susanna Genedani ◽  
Diego Guidolin ◽  
...  

AbstractMultiple players are involved in the brain integrative action besides the classical neuronal and astrocyte networks. In the past, the concept of complex cellular networks has been introduced to indicate that all the cell types in the brain can play roles in its integrative action. Intercellular communication in the complex cellular networks depends not only on well-delimited communication channels (wiring transmission) but also on diffusion of signals in physically poorly delimited extracellular space pathways (volume transmission). Thus, the extracellular space and the extracellular matrix are the main players in the intercellular communication modes in the brain. Hence, the extracellular matrix is an ‘intelligent glue’ that fills the brain and, together with the extracellular space, contributes to the building-up of the complex cellular networks. In addition, the extracellular matrix is part of what has been defined as the global molecular network enmeshing the entire central nervous system, and plays important roles in synaptic contact homeostasis and plasticity. From these premises, a concept is introduced that the global molecular network, by enmeshing the central nervous system, contributes to the brain holistic behavior. Furthermore, it is suggested that plastic ‘brain compartments’ can be detected in the central nervous system based on the astrocyte three-dimensional tiling of the brain volume and on the existence of local differences in cell types and extracellular space fluid and extracellular matrix composition. The relevance of the present view for neuropsychiatry is discussed. A glossary box with terms and definitions is provided.


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