Electron Microscopical Studies of Human Malignant Hepatoma Cells (1)

In order to obtain specific and optimal ultrastructural localization of vasopressin and oxytocin in the hypothalamo-neurohypophyseal system of the rat, 2 staining procedures and several tissue treatments were evaluated using neurohypophyseal tissue. It appeared from these studies that post-embedding staining with the unlabeled antibody enzyme method developed by Sternberger allows greater dilution of the first antibody (anti-vasopressin, 1:4800) than the indirect procedure (1:320) using a peroxidase conjugate as second antibody. Immersion fixation with 4% formalin during 24 hours gave better results (general ultrastructure, immunoreactivity) than those obtained by perfusion fixation with 2.5% glutaraldehyde-1% paraformaldehyde or freeze substitution.Since no reliable specificity tests were performed at the electron microscopical level, tests were developed for antibodies against both vasopressin and oxytocin. For anti-vasopressin plasma neural lobes of homozygous Brattleboro rats, that are lacking vasopressin by a genet- ical defect, were used. For antibodies against both hormones serial sections were used that were alternately incubated with the antibodies.

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A light optical diffractometer for electron microscopical images operating in line

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107575 ◽

1978 ◽

Vol 36 (1) ◽

pp. 86-87

Author(s):

P. Bonhomme ◽

A. Beorchia

Keyword(s):

Electron Microscopy ◽

Electron Transfer ◽

Electron Microscope ◽

Image Converter ◽

Coherent Light ◽

Spatial Filters ◽

Electron Image ◽

Electron Microscopical ◽

Working Parameters ◽

Amorphous Part

We have already described (1.2.3) a device using a pockel's effect light valve as a microscopical electron image converter. This converter can be read out with incoherent or coherent light. In the last case we can set in line with the converter an optical diffractometer. Now, electron microscopy developments have pointed out different advantages of diffractometry. Indeed diffractogram of an image of a thin amorphous part of a specimen gives information about electron transfer function and a single look at a diffractogram informs on focus, drift, residual astigmatism, and after standardizing, on periods resolved (4.5.6). These informations are obvious from diffractogram but are usualy obtained from a micrograph, so that a correction of electron microscope parameters cannot be realized before recording the micrograph. Diffractometer allows also processing of images by setting spatial filters in diffractogram plane (7) or by reconstruction of Fraunhofer image (8). Using Electrotitus read out with coherent light and fitted to a diffractometer; all these possibilities may be realized in pseudoreal time, so that working parameters may be optimally adjusted before recording a micrograph or before processing an image.

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Ultrastructure of the soil fungus, Geomyces pannorus

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100113573 ◽

1984 ◽

Vol 42 ◽

pp. 738-739

Author(s):

J. A. Traquair ◽

E. G. Kokko

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Fine Structure ◽

Low Temperatures ◽

Soil Fungus ◽

Organic Soils ◽

Anatomical Studies ◽

Transmission Electron ◽

Electron Microscopical ◽

Scanning Electron

With the advent of improved dehydration techniques, scanning electron microscopy has become routine in anatomical studies of fungi. Fine structure of hyphae and spore surfaces has been illustrated for many hyphomycetes, and yet, the ultrastructure of the ubiquitous soil fungus, Geomyces pannorus (Link) Sigler & Carmichael has been neglected. This presentation shows that scanning and transmission electron microscopical data must be correlated in resolving septal structure and conidial release in G. pannorus.Although it is reported to be cellulolytic but not keratinolytic, G. pannorus is found on human skin, animals, birds, mushrooms, dung, roots, and frozen meat in addition to various organic soils. In fact, it readily adapts to growth at low temperatures.

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Etching of Polymers by Oxygen Plasma

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101797 ◽

1968 ◽

Vol 26 ◽

pp. 408-409

Author(s):

Virgil Peck ◽

W. L. Carter

Keyword(s):

Molecular Weight ◽

Oxygen Plasma ◽

Flow Time ◽

Microscopical Study ◽

Surface Layers ◽

Organic Vapors ◽

Sample Position ◽

Accuracy Of Measurement ◽

Bulk Polymers ◽

Electron Microscopical

Any electron microscopical study of the morphology of bulk polymers has throughout the years been hampered by the lack of any real ability to produce meaningful surface variations for replication. True etching of polymers should show crystalline and amorphous regions in some form of relief. The use of solvents, acids, organic vapors, and inert ion bombardment to etch samples has proved to be useful only in limited applications. Certainly many interpretations of these results are subject to question.The recent use of a radiofrequency (R. F.) plasma of oxygen to degrade and remove organic material with only minor heating has opened a new possibility for etching polymers. However, rigid control of oxygen flow, time, current, and sample position are necessary in order to obtain reproducible results. The action is confined to surface layers; the molecular weight of the polymer residue after heavy etching is the same as the molecular weight of the polymer before attack, within the accuracy of measurement.

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The Fine Structure of Phloem Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100119867 ◽

1985 ◽

Vol 43 ◽

pp. 632-635

Author(s):

James Cronshaw

Keyword(s):

Structural Studies ◽

High Concentration ◽

Long Distance ◽

Phloem Tissue ◽

Sieve Elements ◽

Long Distance Transport ◽

P Protein ◽

Companion Cells ◽

Electron Microscopical ◽

Distance Transport

Long distance transport in plants takes place in phloem tissue which has characteristic cells, the sieve elements. At maturity these cells have sieve areas in their end walls with specialized perforations. They are associated with companion cells, parenchyma cells, and in some species, with transfer cells. The protoplast of the functioning sieve element contains a high concentration of sugar, and consequently a high hydrostatic pressure, which makes it extremely difficult to fix mature sieve elements for electron microscopical observation without the formation of surge artifacts. Despite many structural studies which have attempted to prevent surge artifacts, several features of mature sieve elements, such as the distribution of P-protein and the nature of the contents of the sieve area pores, remain controversial.

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Investigation of thin sections of biological standards by EDX, EELS, and Auger electron spectroscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010013451x ◽

1990 ◽

Vol 48 (2) ◽

pp. 184-185

Author(s):

S. Lehner ◽

H.E. Bauer ◽

R. Wurster ◽

H. Seiler

Keyword(s):

Processing System ◽

Beam Current ◽

Beam Diameter ◽

Thin Sections ◽

Biologically Relevant ◽

Energy Filtering ◽

Low Viscosity ◽

Carbon Foils ◽

Electron Microscopical ◽

Exchange Membrane

In order to compare different microanalytical techniques commercially available cation exchange membrane SC-1 (Stantech Inc, Palo Alto), was loaded with biologically relevant elements as Na, Mg, K, and Ca, respectively, each to its highest possible concentration, given by the number concentration of exchangeable binding sites (4 % wt. for Ca). Washing in distilled water, dehydration through a graded series of ethanol, infiltration and embedding in Spurr’s low viscosity epoxy resin was followed by thin sectioning. The thin sections (thickness of about 50 nm) were prepared on carbon foils and mounted on electron microscopical finder grids.The samples were analyzed with electron microprobe JXA 50A with transmitted electron device, EDX system TN 5400, and on line operating image processing system SEM-IPS, energy filtering electron microscope CEM 902 with EELS/ESI and Auger spectrometer 545 Perkin Elmer.With EDX, a beam current of some 10-10 A and a beam diameter of about 10 nm, a minimum-detectable mass of 10-20 g Ca seems within reach.

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Stain contamination and embedding in electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100141986 ◽

1986 ◽

Vol 44 ◽

pp. 50-53

Author(s):

Hilton H. Mollenhauer

Keyword(s):

Electron Microscopy ◽

Information Retrieval ◽

Epoxy Resins ◽

Image Contrast ◽

Sample Preservation ◽

Factors Associated ◽

Amount Of Information ◽

Electron Microscopical ◽

Contrast Information

Many factors (e.g., resolution of microscope, type of tissue, and preparation of sample) affect electron microscopical images and alter the amount of information that can be retrieved from a specimen. Of interest in this report are those factors associated with the evaluation of epoxy embedded tissues. In this context, informational retrieval is dependant, in part, on the ability to “see” sample detail (e.g., contrast) and, in part, on tue quality of sample preservation. Two aspects of this problem will be discussed: 1) epoxy resins and their effect on image contrast, information retrieval, and sample preservation; and 2) the interaction between some stains commonly used for enhancing contrast and information retrieval.

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