scholarly journals Morphological Signs of Dystrophy, Regeneration and Hypertrophy of Neurons

2021 ◽  
pp. 1-6
Author(s):  
Bon EI ◽  
◽  
Malykhina AV ◽  

Results: Dystrophic changes constitute an extensive group of neuronal disorders and are manifested at the morphological level by deformation of the perikarions and neuropil, wrinkling or swelling of the cell, and changes in the chromatophilia of the cytoplasm. At the electron microscopic level, disorganization of organelles is observed, reflecting gross violations of the vital processes of the neuron. There are several ways to regenerate neurons: intracellular regeneration, restoration of the neuropil, the formation of new neurons (in some parts of the nervous system - the hippocampus, the subventricular layer of the lateral ventricles and olfactory bulbs) and the formation of heterokaryons (fusion of a neuron with an oligodendrocyte). Hypertrophy of neurons may indicate both compensation and the development of a pathological process. To clarify the nature of this phenomenon, it is necessary to conduct an ultramicroscopic study of the organelles of the nerve cell.

1962 ◽  
Vol 12 (2) ◽  
pp. 385-410 ◽  
Author(s):  
Sanford L. Palay ◽  
S. M. McGee-Russell ◽  
Spencer Gordon ◽  
Mary A. Grillo

This paper describes in detail a method for obtaining nearly uniform fixation of the nervous system by vascular perfusion with solutions of osmium tetroxide. Criteria are given for evaluating the degree of success achieved in the preservation of all the cellular components of the nervous system. The method permits analysis of the structural relations between cells at the electron microscopic level to an extent that has not been possible heretofore.


Author(s):  
A.M. Milroy ◽  
D.D. Ralston

Multiple labeling at the electron microscopic level is routinely done in various parts of the central nervous system. We demonstrate that the pre-embedding tetramethylbenzidine (TMB) reaction for visualizing horseradish peroxidase (HRP) of Olucha and the slow osmication of Henry combined with a post-embedding nonetching immunogold method will also preserve good ultrastructure. Furthermore, the post-embedding immunocytochemistry of some neurotransmitters, i.e. gammaaminobutyric acid (GABA), can be done months after the tissue has been reacted for HRP and embedded in regular epon.Pre-embedding histochemistry:The use of TMB as a chromagen for the demonstration of neuronally transported HRP has both the advantage of being highly sensitive and of producing very specific needle-like crystals. Olucha et al demonstrated that one could further stabilize this reaction product with amonium heptamolybdate. Unfortunately the next step, fixation with regular osmium tetroxide, often resulted in the loss of the reaction product. However, the slow osmication with a lower pH (5.5) in the phosphate buffer at room temperature as recommended by Henry et al prevented this loss, and at the same time resulted in well preserved ultrastructure.


1980 ◽  
Vol 28 (12) ◽  
pp. 1312-1318 ◽  
Author(s):  
L F Eng ◽  
R J Lasek ◽  
J W Bigbee ◽  
D L Eng

Antibodies prepared in rabbits against Myxicola infundibulum neurofilaments have been employed to stain neurofilaments immunohistochemically in intact Myxicola infundibulum nervous tissue. Paraffin-embedded and frozen sections (5--6 mu) were examined at the light microscopic level with Sternberger's peroxidase-antiperoxidase method, and Vibratome (20--40 mu) sections were studied at the ultrastructural level with Nakane's conjugated peroxidase method. The neurofilament antibody stained only neurons and axons at the light microscopic level. The staining pattern at the electron microscopic level corresponded to the neurofilaments within axons and neurons. Glial cells, which surround the axons, contain large bundles of filaments that resemble astrocytic filaments in mammalian astrocytes. These filaments do not stain with the anti-neurofilament antibody. Neurons, neurofilaments, glial cells, glial filaments, and nonnervous tissue showed no peroxidase staining when specific antiserum absorbed with neurofilaments was used. These structures were also unstained when antiserum to the glial fibrillary acidic protein of mammalian central nervous system astrocytes was substituted for the neurofilament antiserum. Therefore, in Myxicola infundibulum, the antigenic determinants of the neurofilament protein, as recognized immunohistochemically by anti-neurofilament protein antibodies, are not shared with those of glial filaments.


Author(s):  
K. Yoshida ◽  
F. Murata ◽  
S. Ohno ◽  
T. Nagata

IntroductionSeveral methods of mounting emulsion for radioautography at the electron microscopic level have been reported. From the viewpoint of quantitative radioautography, however, there are many critical problems in the procedure to produce radioautographs. For example, it is necessary to apply and develop emulsions in several experimental groups under an identical condition. Moreover, it is necessary to treat a lot of grids at the same time in the dark room for statistical analysis. Since the complicated process and technical difficulties in these procedures are inadequate to conduct a quantitative analysis of many radioautographs at once, many factors may bring about unexpected results. In order to improve these complicated procedures, a simplified dropping method for mass production of radioautographs under an identical condition was previously reported. However, this procedure was not completely satisfactory from the viewpoint of emulsion homogeneity. This paper reports another improved procedure employing wire loops.


Author(s):  
A. Angel ◽  
K. Miller ◽  
V. Seybold ◽  
R. Kriebel

Localization of specific substances at the ultrastructural level is dependent on the introduction of chemicals which will complex and impart an electron density at specific reaction sites. Peroxidase-antiperoxidase(PAP) methods have been successfully applied at the electron microscopic level. The PAP complex is localized by addition of its substrate, hydrogen peroxide and an electron donor, usually diaminobenzidine(DAB). On oxidation, DAB forms an insoluble polymer which is able to chelate with osmium tetroxide becoming electron dense. Since verification of reactivity is visual, discrimination of reaction product from osmiophillic structures may be difficult. Recently, x-ray microanalysis has been applied to examine cytochemical reaction precipitates, their distribution in tissues, and to study cytochemical reaction mechanisms. For example, immunoreactive sites labelled with gold have been ascertained by means of x-ray microanalysis.


1986 ◽  
Vol 34 (6) ◽  
pp. 785-793 ◽  
Author(s):  
W E Howe ◽  
F G Klier ◽  
R G Oshima

The intracellular distribution of extra-embryonic endodermal, cytoskeletal proteins A (Endo A) and B (Endo B) was investigated by double-label immunofluorescent microscopy and double-label immunoelectron microscopy. In parietal endodermal cells, the immunofluorescent distribution of Endo B was always coincident with that of Endo A and could be distinguished from vimentin, particularly at the periphery of the cell. At the electron microscopic level, antibodies against both Endo A and Endo B recognized both bundles and individual intermediate filaments. Double-label immunoelectron microscopy was achieved by use of two sizes of colloidal gold particles (5 nm and 20 nm) that were stabilized with secondary antibodies. These results show that Endo A and B are found in the same intermediate filament and probably co-polymerize to form such structures.


2003 ◽  
Vol 51 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Toshihiro Takizawa ◽  
Clark L. Anderson ◽  
John M. Robinson

Adequate contrast of ultrathin cryosections is crucial for evaluating morphological detail to assess immunocytochemical localization at the electron microscopic level. We have developed a positive staining method for achieving contrast in ultrathin cryosections, from tissue fixed only in paraformaldehyde, that provides excellent contrast at the electron microscopic level.


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