Tract Tracing Methods at the Light Microscopic Level

Author(s):  
Marina Bentivoglio ◽  
Giuseppe Bertini
Author(s):  
D. J. McComb ◽  
J. Beri ◽  
F. Zak ◽  
K. Kovacs

Investigation of the spontaneous pituitary adenomas in rat have been limited mainly to light microscopic study. Furth et al. (1973) described them as chromophobic, secreting prolactin. Kovacs et al. (1977) in an ul trastructural investigation of adenomas of old female Long-Evans rats, found that they were composed of prolactin cells. Berkvens et al. (1980) using immunocytochemistry at the light microscopic level, demonstrated that some spontaneous tumors of old Wistar rats could contain GH, TSH or ACTH as well as PRL.


Author(s):  
Vivian V. Yang ◽  
S. Phyllis Stearner

The heart is generally considered a radioresistant organ, and has received relatively little study after total-body irradiation with doses below the acutely lethal range. Some late damage in the irradiated heart has been described at the light microscopic level. However, since the dimensions of many important structures of the blood vessel wall are submicroscopic, investigators have turned to the electron microscope for adequate visualization of histopathological changes. Our studies are designed to evaluate ultrastructural changes in the mouse heart, particularly in the capillaries and muscle fibers, for 18 months after total-body exposure, and to compare the effects of 240 rad fission neutrons and 788 rad 60Co γ-rays.Three animals from each irradiated group and three control mice were sacrificed by ether inhalation at 4 days, and at 1, 3, 6, 12, and 18 months after irradiation. The thorax was opened and the heart was fixed briefly in situwith Karnofsky's fixative.


Author(s):  
D.F. Clapin ◽  
V.J.A. Montpetit

Alzheimer's disease is characterized by the accumulation of abnormal filamentous proteins. The most important of these are amyloid fibrils and paired helical filaments (PHF). PHF are located intraneuronally forming bundles called neurofibrillary tangles. The designation of these structures as "tangles" is appropriate at the light microscopic level. However, localized domains within individual tangles appear to demonstrate a regular spacing which may indicate a liquid crystalline phase. The purpose of this paper is to present a statistical geometric analysis of PHF packing.


Author(s):  
Rick L. Vaughn ◽  
Shailendra K. Saxena ◽  
John G. Sharp

We have developed an intestinal wound model that includes surgical construction of an ileo-cecal patch to study the complex process of intestinal wound healing. This allows approximation of ileal mucosa to the cecal serosa and facilitates regeneration of ileal mucosa onto the serosal surface of the cecum. The regeneration of ileal mucosa can then be evaluated at different times. The wound model also allows us to determine the rate of intestinal regeneration for a known size of intestinal wound and can be compared in different situations (e.g. with and without EGF and Peyer’s patches).At the light microscopic level it appeared that epithelial cells involved in regeneration of ileal mucosa originated from the enlarged crypts adjacent to the intestinal wound and migrated in an orderly fashion onto the serosal surface of the cecum. The migrating epithelial cells later formed crypts and villi by the process of invagination and evagination respectively. There were also signs of proliferation of smooth muscles underneath the migratory epithelial cells.


Author(s):  
R.V.W. Dimlich ◽  
M.H. Biros

In severe cerebral ischemia, Purkinje cells of the cerebellum are one of the cell types most vulnerable to anoxic damage. In the partial (forebrain) global ischemic (PGI) model of the rat, Paljärvi noted at the light microscopic level that cerebellar damage is inconsistant and when present, milder than in the telencephalon, diencephalon and rostral brain stem. Cerebellar injury was observed in 3 of 4 PGI rats following 5 minutes of reperfusion but in none of the rats after 90 min of reperfusion. To evaluate a time between these two extremes (5 and 90 min), the present investigation used the PGI model to study the effects of ischemia on the ultrastructure of cerebellar Purkinje cells in rats that were sacrificed after 30 min of reperfusion. This time also was chosen because lactic acid that is thought to contribute to ischemic cell changes in PGI is at a maximum after 30 min of reperfusion.


Author(s):  
Masako Yamada ◽  
Yutaka Tanuma

Although many fine structural studies on the vertebrate liver have been reported on mammals, avians, reptiles, amphibians, teleosts and cyclostomes, there are no studies on elasmobranchii liver except one by T. Ito etal. (1962) who studied it on light microscopic level. The purpose of the present study was to as certain the ultrastructural details and cytochemical characteristics of normal elasmobranchii liver and was to compare with the other higher vertebrate ones.Seventeen Scyliorhinus torazame, one kind of elasmobranchii, were obtained from the fish stock of the Ueno Zoo aquarium, Ueno, Tokyo. The sharks weighing about 300-600g were anesthetized with MS-222 (Sigma), and the livers were fixed by perfusion fixation via the portal vein according to the procedure of Y. Saito et al. (1980) for 10 min. Then the liver tissues were immersed in the same fixative for 2 hours and postfixed with 1% OsO4-solution in 0.1 Mc acodylate buffer for one hour. In order to make sure a phagocytic activity of Kupffer cells, latex particles (0.8 μm in diameter, 0.05mg/100 g b.w.) were injected through the portal vein for one min before fixation. For preservation of lipid droplets in the cytoplasm, a series of these procedure were performed under ice cold temperature until the end of dehydration.


Development ◽  
1986 ◽  
Vol 91 (1) ◽  
pp. 65-78
Author(s):  
T. Fukuzawa ◽  
H. Ide

It is still unknown why dermal melanophores disappear during larval development, and why no or very few epidermal melanophores appear during and after metamorphosis, in Xenopus laevis showing periodic albinism (ap). To elucidate these points, we investigated (1) the occurrence of depigmentation in mutant (ap/ap) melanophores during in vitro proliferation and (2) the incidence of melanophore differentiation from mutant melanoblasts in the skin in vitro. During in vitro proliferation of mutant melanophores, ap-type melanosomes decreased in number gradually and instead the number of premelanosomes increased in the cells, which caused depigmentation at the light microscopic level in the culture. Depigmentation was observed only in mutant melanophores, and not in wild-type (+/+) melanophores. These results suggest that autonomous depigmentation of mutant dermal melanophores is the cause of the disappearance of these cells in vivo. Dopa-positive melanoblasts were demonstrated in both wild-type and mutant skins. However, the melanoblasts of metamorphosed mutant froglets did not differentiate in vitro, while those of wild-type froglets did. These results suggest that mutant melanoblasts in the skin of froglets lose the potency to differentiate into melanophores, and that this causes the lack of mutant melanophores in the froglets. The site of action of the ap gene is also discussed.


2017 ◽  
Vol 33 (7) ◽  
pp. 576-587 ◽  
Author(s):  
Marcela Fátima Medina ◽  
María Celeste Arrieta ◽  
Marcela Noemí Villafañe ◽  
Sandra María Roxana Klyver ◽  
Iris María Aybar Odstrcil ◽  
...  

The cadmium (Cd) concentration in the environment has increased as a consequence of anthropogenic activity. The objective of this study was to determine early signs of Cd toxicity in testes and sperm as possible biomarkers. The dose orally administered to Wistar rats was within the range where chronic toxicity can appear. At the light microscopic level, gonads presented preserved cytoarchitecture throughout treatment; however, after the second month, transmission electron microscopy (TEM) revealed disruption of the blood–testis barrier. The study of sperm with light microscopy showed defects in gamete morphology after 2 months of treatment. Another parameter that revealed alteration was sperm motility after 3 months of treatment. TEM was used to analyze the flagellum, which in the midpiece showed aberrant mitochondria and displacement of outer dense fibers in relation to the central axoneme after 2 months. The data obtained were associated with Cd concentration in the testes, an increase in its levels being observed in a time-dependent manner. The results provided in this study demonstrated that early signs of Cd toxicity were observed in gonads and gametes during the second month of the treatment, generating morphological and functional alterations in the sperm that could lead to infertility.


1985 ◽  
Vol 33 (10) ◽  
pp. 995-1000 ◽  
Author(s):  
R B Alexander ◽  
W B Isaacs ◽  
E R Barrack

A method is presented whereby the staining of intracellular structures with immunogold probes for electron microscopy can be evaluated at the light microscopic level. Methanol-fixed monolayers of cultured Dunning R-3327-H rat prostatic adenocarcinoma cells were stained for cytokeratins using a two-step immunogold technique consisting of primary anti-keratin antibody followed by gold-labeled secondary antibody. Bound immunogold probe was then visualized with a fluorescent tertiary anti-immunogold probe antibody. Fluorescence microscopy of the whole cell monolayers showed a typical keratin cytoskeleton. The extra staining step did not interfere with subsequent fixation, embedding, and sectioning for electron microscopy, which showed cytoplasmic intermediate filaments decorated with colloidal gold. Using this method, it should be possible to manipulate parameters critical to staining with immunogold probes and to evaluate the labeling without necessitating repeated time-consuming electron microscopic processing. The method also provides a useful correlation between the light microscopic and ultrastructural labeling patterns of immunogold probes.


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