En Bloc Removal of the Mandible, the Masticatory Muscles and the Mandibular Nerve in the Chimpanzee (Pan troglodytes, Blumenbach 1799), with a Review and Critique of the Methods Used to Expose the Trigeminal Musculature in Derived Primates

Uranyl acetate has been used as an electron stain for en bloc staining as well as for staining ultrathin sections in conjunction with various lead stains (Fig. 1). Present studies reveal that various platinum compounds also show promise as electron stains. Certain platinum compounds have been shown to be effective anti-tumor agents. Of particular interest are the compounds with either uracil or thymine as one of the ligands (cis-Pt(II)-uracil; cis-Pt(II)-thymine). These compounds are amorphous, highly soluble in water and often exhibit an intense blue coloration. These compounds show enough electron density to be used as stains for electron microscopy. Most of the studies are based on various cell lines (human AV, cells, human lymphoma cells, KB cells, Sarcoma-180 ascites cells, chick fibroblasts and HeLa cells) while studies on tissue blocks are in progress.

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Cellular Contacts Within the Interhemal Membrane of the Rat Placenta at Term

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050743 ◽

1974 ◽

Vol 32 ◽

pp. 146-147

Author(s):

William P. Jollie

Keyword(s):

Osmium Tetroxide ◽

Uranyl Acetate ◽

Capillary Endothelium ◽

En Bloc ◽

Aldehyde Fixation ◽

Chorioallantoic Placenta

By routine EM preparative techniques, the tissues which, collectively, separate maternal and fetal bloods in the fully formed chorioallantoic placenta of the rat have been shown to consist of three chorionic layers, or trophoblast, and a layer of allantoic capillary endothelium [Fig. 1]. Relationships between these layers are best demonstrated by special techniques, viz., cacodylate-buffered aldehyde fixation, collidine-buffered osmium tetroxide postfixation, and en bloc staining with uranyl acetate. By using this method on placentas at term, the cells of the outermost chorionic layer (Trophoblast 1) appear to be attached to each other by means of maculae adherentes which sometimes occur in clusters [Fig. 2].

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Localization of pancreatic enzymes in ultrathin frozen sections stained with metal labeled antibody

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081310 ◽

1978 ◽

Vol 36 (2) ◽

pp. 90-91

Author(s):

Kenjiro Yasuda

Keyword(s):

Fluorescent Antibody ◽

Pancreatic Enzymes ◽

Tissue Preparation ◽

Zymogen Granules ◽

Frozen Sections ◽

En Bloc ◽

Antibody Method ◽

Ultrathin Frozen Sections ◽

Fluorescent Antibody Method

Localization of amylase,chymotrypsinogen and trypsinogen in pancreas was demonstrated by Yasuda and Coons (1966), by using fluorescent antibody method. These enzymes were naturally found in the zymogen granules. Among them, amylase showed a diffuse localization around the nucleus, in addition to the zymogen granules. Using ferritin antibody method, scattered ferritin granules were also found around the Golgi area (Yasuda et al.,1967). The recent advance in the tissue preparation enables the antigen to be localized in the ultrathin frozen sections, by applying the labeled antibodies onto the sections instead of staining the tissue en bloc.The present study deals with the comparison of the localization of amylase and lipase demonstrated by applying the bismuth-labeled, peroxidase-labeled and ferritin-labeled antibody methods on the ultrathin frozen sections of pancreas, and on the blocks of the same tissue.

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Lead aspartate: a new en bloc stain for electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081036 ◽

1978 ◽

Vol 36 (2) ◽

pp. 34-35

Author(s):

J.R. Walton

Keyword(s):

Electron Microscopy ◽

Calcium Ion ◽

Enzyme Reaction ◽

Lead Citrate ◽

Reaction Products ◽

En Bloc ◽

Thin Sections ◽

Lead Salts ◽

Thin Sectioning ◽

High Alkalinity

In electron microscopy, lead is the metal most widely used for enhancing specimen contrast. Lead citrate requires a pH of 12 to stain thin sections of epoxy-embedded material rapidly and intensively. However, this high alkalinity tends to leach out enzyme reaction products, making lead citrate unsuitable for many cytochemical studies. Substitution of the chelator aspartate for citrate allows staining to be carried out at pH 6 or 7 without apparent effect on cytochemical products. Moreover, due to the low, controlled level of free lead ions, contamination-free staining can be carried out en bloc, prior to dehydration and embedding. En bloc use of lead aspartate permits the grid-staining step to be bypassed, allowing samples to be examined immediately after thin-sectioning.Procedures. To prevent precipitation of lead salts, double- or glass-distilled H20 used in the stain and rinses should be boiled to drive off carbon dioxide and glassware should be carefully rinsed to remove any persisting traces of calcium ion.

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Quantitative EM of gap junction distribution in mutant drosophila wing discs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100077177 ◽

1983 ◽

Vol 41 ◽

pp. 720-721

Author(s):

J.S. Ryerse

Keyword(s):

Gap Junctions ◽

Growth Control ◽

Intercellular Junctions ◽

Wing Disc ◽

En Bloc ◽

Metabolic Cooperation ◽

Drosophila Wing ◽

Adult Wing ◽

Wing Discs ◽

Wing Pouch

Gap junctions are intercellular junctions found in both vertebrates and invertebrates through which ions and small molecules can pass. Their distribution in tissues could be of critical importance for ionic coupling or metabolic cooperation between cells or for regulating the intracellular movement of growth control and pattern formation factors. Studies of the distribution of gap junctions in mutants which develop abnormally may shed light upon their role in normal development. I report here the distribution of gap junctions in the wing pouch of 3 Drosophila wing disc mutants, vg (vestigial) a cell death mutant, 1(2)gd (lethal giant disc) a pattern abnormality mutant and 1(2)gl (lethal giant larva) a neoplastic mutant and compare these with wildtype wing discs.The wing pouch (the anlagen of the adult wing blade) of a wild-type wing disc is shown in Fig. 1 and consists of columnar cells (Fig. 5) joined by gap junctions (Fig. 6). 14000x EMs of conventionally processed, UA en bloc stained, longitudinally sectioned wing pouches were enlarged to 45000x with a projector and tracings were made on which the lateral plasma membrane (LPM) and gap junctions were marked.

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Ultrastructural comparison of prolactin adenomas of pituitary in men and women

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100103796 ◽

1988 ◽

Vol 46 ◽

pp. 346-347

Author(s):

R.C. Caughey ◽

U.P. Kalyan-Raman

Keyword(s):

Endoplasmic Reticulum ◽

Electron Microscope ◽

Phosphate Buffer ◽

Pituitary Adenomas ◽

Osmium Tetroxide ◽

Secretory Granules ◽

Uranyl Acetate ◽

En Bloc ◽

Men And Women ◽

Transmission Electron

Prolactin producing pituitary adenomas are ultrastructurally characterized by secretory granules varying in size (150-300nm), abundance of endoplasmic reticulum, and misplaced exocytosis. They are also subclassified as sparsely or densely granulated according to the amount of granules present. The hormone levels in men and women vary, being higher in men; so also the symptoms vary between both sexes. In order to understand this variation, we studied 21 prolactin producing pituitary adenomas by transmission electron microscope. This was out of a total of 80 pituitary adenomas. There were 6 men and 15 women in this group of 21 prolactinomas.All of the pituitary adenomas were fixed in 2.5% glutaraldehyde, rinsed in Millonig's phosphate buffer, and post fixed with 1% osmium tetroxide. They were then en bloc stained with 0.5% uranyl acetate, rinsed with Walpole's non-phosphate buffer, dehydrated with graded series of ethanols and embedded with Epon 812 epoxy resin.

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