scholarly journals Formaldehyde as a Fixative for Light and Electron Microscopy

2000 ◽  
Vol 8 (3) ◽  
pp. 34-35
Author(s):  
Freida L. Carson
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Light And Electron Microscopy ◽  
Parallel Study ◽  
Electron Microscopic ◽  
Dual Purpose ◽  
Ultrastructural Morphology ◽  
The World ◽  
Selection Of

Since Blum discovered its hardening properties in 1893, formaldehyde has become the most widely used fixative in the world for specimens to be examined by light microscopy. However, since most commercial preparations of formaldehyde contain methanol, a protein precipitant, formaldehyde has been considered an unsatisfactory fixative for tissues to be examined by electron microscopy.In 1973, Carson et a/, described a parallel study comparing the electron microscopic results of fixation with paraformaldehyde vs. formaldehyde. They found that there was no difference in the preservation of ultrastructural morphology provided that the buffer systems were identical. In 1976, McDowell and Trump described a fixative combining commercial formaldehyde and glutaraldehyde (4CF-1G). Both of these fixatives are dual purpose fixatives and preclude the selection of tissue for electron microscopy prior to fixation. They can both be prepared in large quantities and used for routine surgical specimens.

scholarly journals Formaldehyde as a Fixative for Light and Electron Microscopy

2000 ◽  
Vol 8 (5) ◽  
pp. 30-31
Author(s):  
Freida L. Carson
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Light And Electron Microscopy ◽  
Parallel Study ◽  
Electron Microscopic ◽  
Dual Purpose ◽  
Ultrastructural Morphology ◽  
The World ◽  
Selection Of

Since Blum discovered its hardening properties in 1893, formaldehyde has become the most widely used fixative in the world for specimens to be examined by light microscopy. However, since most commercial preparations of formaldehyde contain methanol, a protein precipitant, formaldehyde has been considered an unsatisfactory fixative for tissues to be examined by electron microscopy. In 1973, Carson et al., described a parallel study comparing the electron microscopic results of fixation with paraformaidehyde vs. formaldehyde. They found that there was no difference in the preservation of ultrastructural morphology provided that the buffer systems were identical. In 1976, McDowell and Trump described a fixative combining commercial formaldehyde and glutaraldehyde (4CF-1G). Both of these fixatives are dual purpose fixatives and preclude the selection of tissue for electron microscopy prior to fixation. They can both be prepared in large quantities and used for routine surgical specimens. The fixative containing formaldehyde alone does not need to be refrigerated and is stable for months; whereas, the formaldehyde-glutaraldehyde mixture should be refrigerated.

scholarly journals THE GLOMERULUS IN EXPERIMENTAL RENAL DISEASE IN RATS AS OBSERVED BY LIGHT AND ELECTRON MICROSCOPY

1955 ◽  
Vol 102 (5) ◽  
pp. 573-580 ◽  
Author(s):  
Carolyn F. Piel ◽  
Luther Dong ◽  
F.W.S. Modern ◽  
Joseph R. Goodman ◽  
Roger Moore
Keyword(s):  
Electron Microscopy ◽  
Endothelial Cells ◽  
Basement Membrane ◽  
Light Microscopy ◽  
Light And Electron Microscopy ◽  
Electron Microscopic ◽  
Crescent Formation ◽  
Colloidal Iron ◽  
Narrow Channels ◽  
Glomerular Capillary

Nephrotoxic serum disease in rats has been studied by light and electron microscopy from 1 hour to 10 weeks after production of the disease. By light microscopy leucocytic infiltration of the glomerular capillary was observed between the 3rd and 6th hour. At 6 hours an increase in colloidal iron-positive material was observed coating the extraluminal surface of the capillaries. Also at this time swelling of the endothelial cells becomes prominent. By 72 hours, thickening of the basement membrane was observed. Glomerular capillary thrombi were observed in approximately half the tissue examined in the first 2 weeks of disease. 50 per cent of the animals showed severe chronic lesions, exudation into the capsular space, crescent formation, and obliteration of glomeruli. At 1 hour electron microscopic pictures showed that osmophilic material may line the foot processes of the epithelial cells and obliterate all but narrow channels of the space between the feet. By 6 hours thickening of the basement membrane was prominent. This change persisted throughout 10 weeks of observation. The tissue from animals which had severe chronic alterations by light microscopy revealed changes which could not be interpreted at this time.

Ruthenium red-osmium bridging with TCH: new technique to stain biological specimens for light and TEM and to coat them for SEM

1988 ◽  
Vol 46 ◽  
pp. 20-21
Author(s):  
B. Giammara ◽  
J. Hanker
Keyword(s):  
Electron Microscopy ◽  
Microscopic Study ◽  
Osmium Tetroxide ◽  
Light And Electron Microscopy ◽  
Ruthenium Red ◽  
Surface Coat ◽  
Repeated Application ◽  
Electron Microscopic ◽  
Sputter Coating ◽  
Selection Of

The demonstration and coating of glycomacromolecular surface coat components of biological specimens (1) with ruthenium red (RR, Fig. 1) is improved by treating with osmium tetroxide (2) probably due to its attachment to glycolipids. Since 1966 studies have shown how bridging osmium to osmium with thiocarbohydrazide (TCH, Fig. 2) can result in improvement in contrast of biological specimens (3,4) for light and electron microscopy. Since 1973 this bridging procedure has widely been applied (5,6) to obtain a conductive coating for biological specimens for SEM eliminating the need for sputter coating. Improvement in conductance of uncoated specimens for EM has also been obtained (6) by bridging osmium with p-phenylenediamine hydrochloride (PPD). The improvement in conductance of RR coated biological specimens for SEM by OsO4 treatment without TCH (2) required repeated application of the reagent solutions and did not result in sufficient staining of the glycomacromolecules and glycolipids for the light microscopic selection of areas for electron microscopic study.

scholarly journals A Histochemical Approach to Correlative Light and Electron Microscopic Detection of Acidic Glycoconjugates by a Sensitized High Iron Diamine Method

1998 ◽  
Vol 46 (6) ◽  
pp. 767-770 ◽  
Author(s):  
Yoshifumi Hirabayashi ◽  
Kazuyori Yamada
Keyword(s):  
Electron Microscopy ◽  
Heavy Metals ◽  
Light Microscopy ◽  
Light And Electron Microscopy ◽  
Reaction Products ◽  
Electron Microscopic ◽  
Microscopic Method ◽  
Final Reaction ◽  
High Iron ◽  
Electron Microscopic Method

A sensitized high iron diamine method is among the reliable and useful histochemical means of detecting acidic glycoconjugates by light microscopy. Because the final reaction products obtained using this method are heavy metals, it can be applied to specimens for visualization by both light and electron microscopy. In this study the high iron diamine method was utilized successfully as a correlative light and electron microscopic method for detection of acidic glycoconjugates.

scholarly journals Alport’s syndrome and benign familial haematuria: Light and electron microscopic studies of the kidney

2008 ◽  
Vol 136 (Suppl. 4) ◽  
pp. 275-281
Author(s):  
Jovan Dimitrijevic ◽  
Vera Todorovic ◽  
Anastasija Aleksic ◽  
Dijana Jovanovic ◽  
Dijana Pilcevic ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Light And Electron Microscopy ◽  
Definitive Diagnosis ◽  
Basement Membranes ◽  
Tissue Slices ◽  
Electron Microscopic ◽  
Tissue Samples ◽  
Hereditary Nephritis ◽  
Hereditary Nephropathy

INTRODUCTION. Hereditary nephropathy is clinically characterized by the familial occurrence in successive generations of progressive haematuric nephritis and neural hearing loss. Hereditary nephropathy of Alport?s syndrome (AS) and benign familial (recurrent) haematuria (BFH) are morphologically characterized by specific and diagnostically important thickening and splitting of lamina densa of the glomerular basement membranes. Those lesions can be recognized only by electron microscopy. Hereditary nephritis is usually present clinically with haematuria, and new mutations without a family history of haematuria. It is therefore important to differentiate hereditary nephritis from BFH and no familial haematuria. Thus, electron microscopy is essential in diagnosis of haematuria. OBJECTIVE. The aim of this study was to describe, by light microscopy, constellation of renal alterations by which hereditary nephropathy can be recognized with high probability as well as to compare the diagnostic validity of the findings observed by light and electron microscopy in AS and BFH. METHOD. We examined 48 renal biopsies of the patients with hereditary nephoropathies by light and electron microscopy. Tissue samples were fixed in buffered paraformaldehyde and embedded in paraffin for long-term preservation. For the electron microscopy analysis, the following fixation in 4% glutaraldehyde tissue was postfixed in 1% osmium tetroxide. Thereafter, the following dehydration procedure tissue slices were embedded in epon. RESULTS. Our results demonstrated that the interstitial foam cells, foetal-like glomeruli, minimal glomerular abnormalities with stain less intense in basement membranes, mild irregular mesangial widening, focal thickening of Bowman?s capsule, foci of dilatation tubules, tubular ectasia and atrophy, erythrocyte tubules casts were present in hereditary nephritis. Additionally, light microscopic biopsy findings in patients with BFH were either normal or revealed minor changes (e.g. increased mesangial matrix). All biopsies were reevaluated by electron microscopy and ultrastructural findings confirmed the diagnosis of hereditary nephropathies. CONCLUSION. The findings observed by light microscopy represent an important step that leads to a definitive diagnosis of AS and BFH. The definitive diagnosis, however, depends on electron microscopy.

Immunocytochemistry. A Review of Methodology for Electron Microscopic Applicaiton

1974 ◽  
Vol 32 ◽  
pp. 328-329
Author(s):  
Joseph E. Mazurkiewicz
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Ultrastructural Level ◽  
Electron Microscopic ◽  
Biological Interest ◽  
Investigative Approach ◽  
Immunologic Activity ◽  
Dense Label

Immunocytochemistry is a powerful investigative approach in which one of the most exacting examples of specificity, that of the reaction of an antibody with its antigen, isused to localize tissue and cell specific molecules in situ. Following the introduction of fluorescent labeled antibodies in T950, a large number of molecules of biological interest had been studied with light microscopy, especially antigens involved in the pathogenesis of some diseases. However, with advances in electron microscopy, newer methods were needed which could reveal these reactions at the ultrastructural level. An electron dense label that could be coupled to an antibody without the loss of immunologic activity was desired.

A Method for Electron Microscopic Study of Tissue Culture Cell Monolayers Grown in Tubes

1967 ◽  
Vol 25 ◽  
pp. 132-133
Author(s):  
R. Stephens ◽  
G. Schidlovsky ◽  
S. Kuzmic ◽  
P. Gaudreau
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Light Microscopy ◽  
Cell Sheet ◽  
Culture Cell ◽  
Tissue Culture Cell ◽  
Electron Microscopic ◽  
Cell Sheets ◽  
Morphological Alterations ◽  
Culture Cells

The usual method of scraping or trypsinization to detach tissue culture cell sheets from their glass substrate for further pelletization and processing for electron microscopy introduces objectionable morphological alterations. It is also impossible under these conditions to study a particular area or individual cell which have been preselected by light microscopy in the living state.Several schemes which obviate centrifugation and allow the embedding of nondetached tissue culture cells have been proposed. However, they all preserve only a small part of the cell sheet and make use of inverted gelatin capsules which are in this case difficult to handle.We have evolved and used over a period of several years a technique which allows the embedding of a complete cell sheet growing at the inner surface of a tissue culture roller tube. Observation of the same cell by light microscopy in the living and embedded states followed by electron microscopy is performed conveniently.

mRNA localization by Electron microscopic in situ hybridization

1991 ◽  
Vol 49 ◽  
pp. 430-431
Author(s):  
J. A. Pollock ◽  
M. Martone ◽  
T. Deerinck ◽  
M. H. Ellisman
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Nucleic Acids ◽  
Recombinant Dna ◽  
Light And Electron Microscopy ◽  
Electron Microscopic ◽  
High Voltage Electron Microscopy ◽  
Functional Sites ◽  
Voltage Electron

Localization of specific proteins in cells by both light and electron microscopy has been facilitate by the availability of antibodies that recognize unique features of these proteins. High resolution localization studies conducted over the last 25 years have allowed biologists to study the synthesis, translocation and ultimate functional sites for many important classes of proteins. Recently, recombinant DNA techniques in molecular biology have allowed the production of specific probes for localization of nucleic acids by “in situ” hybridization. The availability of these probes potentially opens a new set of questions to experimental investigation regarding the subcellular distribution of specific DNA's and RNA's. Nucleic acids have a much lower “copy number” per cell than a typical protein, ranging from one copy to perhaps several thousand. Therefore, sensitive, high resolution techniques are required. There are several reasons why Intermediate Voltage Electron Microscopy (IVEM) and High Voltage Electron Microscopy (HVEM) are most useful for localization of nucleic acids in situ.

The Response of Testis Cells to Low Dose X-Irradiation

1981 ◽  
Vol 39 ◽  
pp. 542-543
Author(s):  
D. E. Philpott ◽  
W. Sapp ◽  
C. Williams ◽  
Joann Stevenson ◽  
S. Black
Keyword(s):  
Electron Microscopy ◽  
Stem Cell ◽  
Light Microscopy ◽  
Dose Level ◽  
Cross Sections ◽  
Low Dose ◽  
Light And Electron Microscopy ◽  
Cellular Responses ◽  
Post Irradiation ◽  
X Irradiation

The response of spermatogonial cells to X-irradiation is well documented. It has been shown that there is a radiation resistent stem cell (As) which, after irradiation, replenishes the seminiferous epithelium. Most investigations in this area have dealt with radiation dosages of 100R or more. This study was undertaken to observe cellular responses at doses less than 100R of X-irradiation utilizing a system in which the tissue can be used for light and electron microscopy.Brown B6D2F1 mice aged 16 weeks were exposed to X-irradiation (225KeV; 15mA; filter 0.35 Cu; 50-60 R/min). Four mice were irradiated at each dose level between 1 and 100 rads. Testes were removed 3 days post-irradiation, fixed, and embedded. Sections were cut at 2 microns for light microscopy. After staining, surviving spermatogonia were identified and counted in tubule cross sections. The surviving fraction of spermatogonia compared to control, S/S0, was plotted against dose to give the curve shown in Fig. 1.

Electron Microscopic Characterization and Quantitation of Air Borne Particulate Matter with Special Emphasis on Asbestos

1972 ◽  
Vol 30 ◽  
pp. 356-357
Author(s):  
Peter K. Mueller ◽  
Glenn R. Smith ◽  
Leslie M Carpenter ◽  
Ronald L. Stanley
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Ambient Air ◽  
Quality Standard ◽  
Primary Objective ◽  
Cellulose Ester ◽  
Main Concept ◽  
Electron Microscopic ◽  
Air Samples ◽  
Diffraction Patterns

At the present time the primary objective of the electron microscopy group of the Air and Industrial Hygiene Laboratory is the development of a method suitable for use in establishing an air quality standard for asbestos in ambient air and for use in its surveillance. The main concept and thrust of our approach for the development of this method is to obtain a true picture of fiber occurrence as a function of particle size and asbestos type utilizing light and electron microscopy.We have now available an electron micrographic atlas of all asbestos types including selected area diffraction patterns and examples of fibers isolated from air samples. Several alternative approaches for measuring asbestos in ambient air have been developed and/or evaluated. Our experiences in this regard will be described. The most promising method involves: 1) taking air samples on cellulose ester membrane filters with a nominal pore size of 0.8 micron; 2) ashing in a low temperature oxygen plasma for several hours;

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