scholarly journals ELECTRON MICROSCOPE STUDIES ON ENZYME ACTIVITY AND THE ISOLATION OF THIOHYDANTOIN-INDUCED MYELIN FIGURES IN RAT LIVER

1965 ◽  
Vol 25 (3) ◽  
pp. 485-493 ◽  
Author(s):  
P. B. Herdson ◽  
J. P. Kaltenbach
Keyword(s):  
Electron Microscope ◽  
Rat Liver ◽  
Osmium Tetroxide ◽  
Enzymatic Reaction ◽  
Cytoplasmic Inclusions ◽  
Thin Sections ◽  
Central Fat ◽  
High Doses ◽  
Parenchymal Cells ◽  
Myelin Figures

Characteristic cytoplasmic inclusions (myelin figures), consisting of concentric multilaminar paired membranes surrounding one or more lipid bodies, were produced in rat liver parenchymal cells by incorporating high doses of an anticonvulsant agent (Bax 422Z) into the animals' diet. Enzymatic reaction product (presumably lead phosphate) was found around the central fat of these myelin figures in liver which had been fixed in glutaraldehyde, incubated in Wachstein and Meisel's medium containing adenosine triphosphate or inosine tri- or diphosphate, postosmicated, embedded in epoxy resin, and examined in the electron microscope. In an attempt to isolate myelin figures, fresh liver from medicated rats was homogenized and differentially centrifuged. Thin sections of osmium tetroxide-fixed, Epon-embedded pellets from each fraction were examined with the electron microscope. The concentric membranous whorls, which are probably derived from cisternae of the endoplasmic reticulum, broke up as the cells were disrupted and became inextricably mixed with the microsomal fraction. However, when liver previously fixed in formalin for 24 hours was homogenized, the myelin figures remained intact.

Ultrastructure of Testicular Spermatozoon of the Fish Oreochromis Niloticus

1988 ◽  
Vol 46 ◽  
pp. 278-279
Author(s):  
T. Guha ◽  
A. Q. Siddiqui ◽  
P. F. Prentis
Keyword(s):  
Electron Microscope ◽  
Oreochromis Niloticus ◽  
Osmium Tetroxide ◽  
Sperm Cells ◽  
Adult Fish ◽  
Testicular Sperm ◽  
Thin Sections ◽  
Important Fish ◽  
Testicular Spermatozoon ◽  
Diamond Knife

Tilapia, Oreochromis niloticus, is an economically important fish in Saudi Arabia. Elucidation of reproductive biology of this species is necessary for successful breeding program. In this paper we describe fine structure of testicular sperm cells in O, niloticus.Testes from young adult fish were fixed in gluteraldehyde (2%) and osmium tetroxide (1%), both in cacodyl ate buffer. Specimens were processed in the conventional way for electron microscopy and thin sections of tissues (obtained by cutting the blocks with a diamond knife) were stained by ura- nyl acetate and lead citrate. These were examined in a Carl Zeiss electron microscope operated at 40 kV to 60 kV. Sperm cells were obtained from testes by squeezing them in cacodyl ate buffer. They were fixed in gluteraldehyde (2%) in the same buffer, air dried, gold coated and then examined in a Philips scanning electron microscope (SEM) operated at 25kV.The spermatozoon of O. niloticus is consisting of head, midpiece and tail (Fig. 1).

Ultrastructure of the lesion induced by toxin T-514 isolated from K. humboldtiana in the alveolar region of the lung

1992 ◽  
Vol 50 (1) ◽  
pp. 640-641
Author(s):  
Julio Sepúlveda-Saavedra ◽  
Beatriz González-Corona ◽  
Víctor A. Tamez Rodríguez ◽  
Ma. Victoria Bermúdez de Rocha ◽  
Alfredo Piñeyro López
Keyword(s):  
Electron Microscope ◽  
Guinea Pig ◽  
Macaca Fascicularis ◽  
Osmium Tetroxide ◽  
Lead Citrate ◽  
Severe Damage ◽  
Thin Sections ◽  
Alveolar Region ◽  
Histopathological Findings

It has been shown in previous studies that the toxin T-514 isolated from K. humboldtiana induces severe damage to the lung in treated rodents. Histopathological findings include edema, and alveolar hemorrage. However, the ultraestructure of the lesion has not been investigated. In this study we used two species of rodents: Hamster and guinea pig, and a primate: Macaca fascicularis. Animals received different single dosis of the toxin via intraperitoneal. Control animals received only the vehicle (propylen glycol). Inmediately after spontaneous death, lung samples were fixed in Karnovsky-Ito fixative, post fixed in osmium tetroxide and embedded in epon. Thin sections were prepared with an Ultratome V LKB, stained with uranly acetate and lead citrate, and studied in an electron microscope Zeiss-EM109.

Observations of thick and thin sections in a field-emission SEM

1994 ◽  
Vol 52 ◽  
pp. 1018-1019
Author(s):  
W. P. Wergin ◽  
S. Roy ◽  
E. F. Erbe ◽  
C. A. Murphy ◽  
C. D. Pooley
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Chemical Fixation ◽  
Thin Sections ◽  
Transmission Electron ◽  
Conventional Transmission Electron Microscope ◽  
Scanning Electron

Larvae of the nematode, Steinernema carpocapsae Weiser strain All, were cryofixed and freezesubstituted for 3 days in acetone containing 2% osmium tetroxide according to established procedures. Following chemical fixation, the nematodes were brought to room temperature, embedded in Spurr's medium and sectioned for observation with a Hitachi S-4100 field emission scanning electron microscope that was equipped with an Oxford CT 1500 Cryotrans System. Thin sections, about 80 nm thick, similar to those generally used in conventional transmission electron microscope (TEM) studies were mounted on copper grids and stained with uranyl acetate for 30 min and lead citrate for 5 min. Sections about 2 μm thick were also mounted and stained in a similar fashion. The grids were mounted on an Oxford grid holder, inserted into the microscope and onto a cryostage that was operated at ambient temperature. Thick and thin sections of the larvae were evaluated and photographed in the SEM at different accelerating voltages. Figs. 4 and 5 have undergone contrast conversion so that the images would resemble transmitted electron micrographs obtained with a TEM.

Intracisternal microtubules in proximal tubule cells of duck kidney: A serendipitous finding

1987 ◽  
Vol 45 ◽  
pp. 898-899
Author(s):  
M.K. Bhatnagar ◽  
S.M. Snelgrove-Hobson ◽  
P.V.V. Prasada Rao
Keyword(s):  
Electron Microscope ◽  
Proximal Tubule ◽  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Kidney Cortex ◽  
Lead Citrate ◽  
Cell Organelles ◽  
Thin Sections ◽  
Proximal Tubule Cells ◽  
Tubule Cells

Cytpplasmic microtubules, ubiquitous cell organelles, lie free in the cytosol without being compartmented off by membranes. In rare instances, however, intracisternal microtubules (ICM) have been reported in ganglionic neurons of aging dogs and in the proximal tubule cells (PTC) of rabbit kidneys. We report here the presence of ICM in the PTC of the kidneys of Peking ducks (Anas platyrhynhos).A total of 106 Peking ducks (24 males and 24 females of 9 months, 48 females of 15 months, 6 males of 30 months and 2 males and 2 females of 48 months of age) were anesthetized and exsanguinated. Pieces of kidney cortex were fixed in 4% glutaraldehyde in 0.5M phosphate buffer (pH 7.3) at 29°C for four hours. Samples were post fixed in 2% osmium tetroxide for two hours. One micron sections of Epon-embedded cortices were stained with toluidine blue and thin sections (70-70 nm) contrasted with uranyl acetate and lead citrate were examined with a JEOL 100-S electron microscope at 80 kV.

The Effect of Electron Microscopy on Pathological Diagnosis of Neoplasm

1990 ◽  
Vol 48 (3) ◽  
pp. 248-249
Author(s):  
Xiaojun Zhou ◽  
Taihe Zhang
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Osmium Tetroxide ◽  
Frozen Section ◽  
Protein A ◽  
Functional Classification ◽  
Lead Citrate ◽  
Thin Sections ◽  
Tumor Tissues ◽  
Frozen Section Diagnosis

Although electron microscopy (EM) has contributed enormously to an understanding of the structural intricacies of tumor cells, the usefulness of EM in pathological diagnoses of neoplasms has not been readily appreciated by general pathologists. In the present study, 223 tumors submitted for EM diagnosis were analyzed in an attempt to gain further information concerning the contribution of EM to tumor diagnosis.223 neoplasms were submitted to EM for their final diagnoses when histopathological diagnoses were obscure, which represented about of the total number of surgical tumor specimens. Most specimens were taken at the time of frozen section diagnosis and a small number of tissues were originally fixed informaldehyde. All of tissues were fixed with buffered glutaradehyde, postfixed with osmium tetroxide and embedded in Epon 812. Ultrasections were made after semith in sections were examined to verify that representative tumor tissues were present. Thin sections were stained with uranium acetate and lead citrate, and examined under JEM-1200 EX electron microscope. In selected cases, mainly with neuroendocrine tumors, nickel grid-mounted sections were subjected to post embedding immunoelectron microscopy (IEM) using protein A-gold for more detailed functional classification. Protein A-gold probes were prepared as Wang and co-workers described.

scholarly journals ON THE FINE STRUCTURE AND COMPOSITION OF THE NUCLEAR ENVELOPE

1961 ◽  
Vol 11 (3) ◽  
pp. 559-570 ◽  
Author(s):  
R. W. Merriam
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Nuclear Envelope ◽  
Pore Structure ◽  
Potassium Permanganate ◽  
Osmium Tetroxide ◽  
Rana Pipiens ◽  
Total Density ◽  
Thin Sections ◽  
Whole Mounts

Nuclei from nearly ripe eggs of Rana pipiens were isolated and cleaned in 0.1 M KCl. The whole nucleus was then digested to various degrees with ribonuclease or trypsin, followed by washing and fixation in either osmium tetroxide or potassium permanganate. The nuclear envelope was dissected off, placed on a grid, air dried, and compared with undigested controls in the electron microscope. Some envelopes were dehydrated, embedded in methacrylate, and sectioned. Annuli around "pores" are composed of a substance or substances, at least partially fibrillar, which is preserved by osmium but lost during permanganate fixation. Material within the "pores" is also preserved by osmium but partially lost after permanganate. No evidence of granules or tubules in the annuli was found in air dried mounts although a granular appearance could be seen in tangentially oriented thin sections. Thin sections of isolated envelopes give evidence of diffuse material within the "pores" as well as a more condensed diaphragm across their waists. In whole mounts of the envelope the total density within "pores" is relatively constant from "pore" to "pore." All material within "pores," including the condensed diaphragm, is removable by trypsin digestion. Wispy material from the "pore" structure projects into the nucleus and annular material extends into the cytoplasm. Both annular and diaphragm materials remain with the envelope when it is isolated and are thus considered a part of its structure, not merely evidences of material passing through. There is no evidence of ribonuclease-removable material in any part of the "pore" complex.

scholarly journals The Striated Musculature of Blood Vessels

1959 ◽  
Vol 6 (3) ◽  
pp. 383-392 ◽  
Author(s):  
H. E. Karrer
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Electron Microscope ◽  
Osmium Tetroxide ◽  
Inferior Vena ◽  
Phosphotungstic Acid ◽  
Vena Cava ◽  
Uranyl Acetate ◽  
Transverse Tubules ◽  
Thin Sections

The musculature of small lung veins, of the thoracic portion of the inferior vena cava, and of other thoracic veins of the mouse have been studied in the electron microscope. Tissues were fixed in 1 per cent osmium tetroxide buffered with veronal, to which either sodium chloride or sucrose had been added. Methacrylate or araldite served as embedding matrices. Phosphotungstic acid or uranyl acetate was used to stain some of the preparations. Thin sections were examined in a Siemens and Halske Elmiskop Ib electron microscope. The entire musculature of the veins examined was of the striated type. It represents a variety of cardiac muscle, characterized by centrally located nuclei, typical mitochondria, and narrow I bands. Many I bands cannot be recognized at all. H and M bands are likewise indistinct. There is a double array of primary and secondary myofilaments. Mitochondria are large and numerous and contain many cristae. The endoplasmic reticulum consists of longitudinal tubules which run through the whole sarcomeres and bypass Z bands, and of transverse tubules which accompany Z bands. Some "triads," located at Z levels, consist of flattened vacuoles flanked by such transverse tubules. Small vesicles located at Z bands, close to the nucleus, and beneath the plasma membrane may represent still other portions of the reticulum.

scholarly journals An Electron Microscope Study of Myelin Figures

1959 ◽  
Vol 5 (3) ◽  
pp. 491-500 ◽  
Author(s):  
Walther Stoeckenius
Keyword(s):  
Molecular Structure ◽  
Electron Microscope ◽  
Fatty Acid ◽  
Human Brain ◽  
Electron Microscope Study ◽  
Striking Similarity ◽  
Fixed Tissue ◽  
Thin Sections ◽  
Tissue Sections ◽  
Myelin Figures

In the electron microscope, thin sections of OsO4-fixed myelin figures from the phospholipide fraction of human brain show a pattern of parallel dark lines with a repeating period of about 40 A. It is shown that the dark lines probably represent the reaction product of OsO4 with double bonds in the fatty acid chains, thereby marking the central portion of one bimolecular lamella. The addition of globin results in dense lines 25 to 50 A wide that cover the surface of the myelin figures. When such a figure consists of only two bimolecular leaflets of lipide covered with globin, the structure shows striking similarity to the image of cell membranes in fixed tissue sections. A hypothetical schema is given of the molecular structure of the figure, and the distribution of OsO4 in it.

scholarly journals PRESERVATION OF MYELIN LAMELLAR STRUCTURE IN THE ABSENCE OF LIPID

1967 ◽  
Vol 34 (3) ◽  
pp. 817-826 ◽  
Author(s):  
Leonard Napolitano ◽  
Francis Lebaron ◽  
Joseph Scaletti
Keyword(s):  
Fatty Acids ◽  
Liquid Chromatography ◽  
Fine Structure ◽  
Electron Microscope ◽  
Lamellar Structure ◽  
Osmium Tetroxide ◽  
Gas Liquid Chromatography ◽  
Glutaraldehyde Fixation ◽  
Thin Sections ◽  
Sciatic Nerves

The fine structure of myelin was studied in glutaraldehyde-fixed rat sciatic nerves depleted of lipid by acetone, chloroform:methanol (2:1 v/v), and chloroform:methanol:concentrated HCl (200:100:1, v/v/v). One portion of each of these nerves, plus the extracts, was saponified and analyzed by gas-liquid chromatography for fatty acids. The remainder of each nerve was stained in osmium tetroxide in CCl4 (5g/100cc) and was embedded in Epon 812. Thin sections, examined in the electron microscope, revealed the preservation of myelin lamellar structure with a 170 A periodicity in nerves depleted of 98% of their lipids. Preservation of myelin lamellar structure depended on glutaraldehyde fixation and the introduction of osmium tetroxide in a nonpolar vehicle (CCl4) after the lipids had been extracted. It is concluded that the periodic lamellar structure in electron micrographs of myelin depleted of lipid results from the complexing of osmium tetroxide, plus uranyl and lead stains, with protein.

Mesosome-like Structures in Cryptococcus neoformans Studied by Chemical Fixation and by the Freeze-etching Technique

1968 ◽  
Vol 26 ◽  
pp. 80-81
Author(s):  
M. R. Edwards ◽  
S. C. Holt
Keyword(s):  
Electron Microscope ◽  
Cryptococcus Neoformans ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Chemical Fixation ◽  
Etching Technique ◽  
Pathogenic Yeast ◽  
Thin Sections ◽  
Lead Salts ◽  
Freeze Etching

The general features of Cryptococcus neoformans, a pathogenic yeast, have been studied with the electron microscope. In the course of such a study it was noted that the plasma membrane of C. neoformans, occasionally invaginated into the cytoplasm and formed membranous organelles which resembled bacterial mesosomes. The present investigation was undertaken in order to examine such structures in detail and to compare the results from chemical fixation with those of freeze-etching.Cells were grown in Sabouraud's agar at 25-27° C for 24-48 hr and fixed with 4% glutaraldehyde in 0.15 M phosphate (Sbrensen's) buffer, at room temperature, for 2 hr; after being thoroughly washed in the buffer and post-fixed in osmium tetroxide, in the same buffer, they were dehydrated in ethyl alcohol and embedded in Epon. Thin sections were cut in a LKB microtome, double stained with uranyl and lead salts and examined in the Siemens Elmiskop IA.

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