Analysis of Plasma Products for Cellular Contaminants: Comparing Standard Preparation Methods

The mammary gland ultrastructure in various functional states is the object of our investigations. The material prepared for electron microscopic examination by the conventional chemical methods has several limitations, the most important are the protein denaturation processes and the loss of large amounts of chemical constituents from the cells. In relevance to this,one can't be sure about a degree the observed images are adequate to the realy ultrastructure of a living cell. To avoid the disadvantages of the chemical preparation methods,some autors worked out alternative physical methods based on tissue freezing / freeze-drying, freeze-substitution, freeze-eatching techniqs/; actually the technique of cryoultraraicrotomy,i,e.cutting ultrathin sections from deep frozen specimens is assented as a complete alternative method. According to the limitations of the routine plastic embbeding methods we were interested to analize the mammary gland ultrastructure during lactation by the cryoultramicrotomy method.

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Enhancement of Contrast in the CEM and STEM Using Bumpy Specimens and Employing the “Dappled Field” Mode of Operation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052778 ◽

1974 ◽

Vol 32 ◽

pp. 552-553 ◽

Cited By ~ 1

Author(s):

L. Gandolfi ◽

J. Reiffel

Keyword(s):

Operating Mode ◽

Scanning Transmission Electron Microscope ◽

Dark Field ◽

Specimen Preparation ◽

Field Mode ◽

Preparation Methods ◽

Scanning Transmission Electron ◽

Transmission Electron ◽

Mode Of Operation ◽

Scanning Transmission

Calculations have been performed on the contrast obtainable, using the Scanning Transmission Electron Microscope, in the observation of thick specimens. Recent research indicates a revival of an earlier interest in the observation of thin specimens with the view of comparing the attainable contrast using both types of specimens.Potential for biological applications of scanning transmission electron microscopy has led to a proliferation of the literature concerning specimen preparation methods and the controversy over “to stain or not to stain” in combination with the use of the dark field operating mode and the same choice of technique using bright field mode of operation has not yet been resolved.

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Structure-property relations of liquid crystalline polymers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100127013 ◽

1987 ◽

Vol 45 ◽

pp. 460-463

Author(s):

Linda C. Sawyer

Keyword(s):

Solid State ◽

Liquid Crystalline ◽

Structural Model ◽

Crystalline Polymer ◽

Liquid Crystalline Polymers ◽

Mechanical Anisotropy ◽

Structure Property ◽

Preparation Methods ◽

Crystalline Polymers ◽

Extended Chain

Recent liquid crystalline polymer (LCP) research has sought to define structure-property relationships of these complex new materials. The two major types of LCPs, thermotropic and lyotropic LCPs, both exhibit effects of process history on the microstructure frozen into the solid state. The high mechanical anisotropy of the molecules favors formation of complex structures. Microscopy has been used to develop an understanding of these microstructures and to describe them in a fundamental structural model. Preparation methods used include microtomy, etching, fracture and sonication for study by optical and electron microscopy techniques, which have been described for polymers. The model accounts for the macrostructures and microstructures observed in highly oriented fibers and films.Rod-like liquid crystalline polymers produce oriented materials because they have extended chain structures in the solid state. These polymers have found application as high modulus fibers and films with unique properties due to the formation of ordered solutions (lyotropic) or melts (thermotropic) which transform easily into highly oriented, extended chain structures in the solid state.

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DNA nick end labeling: a reliable marker for apoptosis?

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100141184 ◽

1995 ◽

Vol 53 ◽

pp. 962-963

Author(s):

Anne F. Bushnell ◽

Sarah Webster ◽

Lynn S. Perlmutter

Keyword(s):

Cell Death ◽

Cultured Cells ◽

Apoptotic Cell ◽

Morphological Characteristics ◽

Detection Methods ◽

Tissue Preparation ◽

Preparation Methods ◽

Dna Laddering ◽

Disease States ◽

Reliable Marker

Apoptosis, or programmed cell death, is an important mechanism in development and in diverse disease states. The morphological characteristics of apoptosis were first identified using the electron microscope. Since then, DNA laddering on agarose gels was found to correlate well with apoptotic cell death in cultured cells of dissimilar origins. Recently numerous DNA nick end labeling methods have been developed in an attempt to visualize, at the light microscopic level, the apoptotic cells responsible for DNA laddering.The present studies were designed to compare various tissue processing techniques and staining methods to assess the occurrence of apoptosis in post mortem tissue from Alzheimer's diseased (AD) and control human brains by DNA nick end labeling methods. Three tissue preparation methods and two commercial DNA nick end labeling kits were evaluated: the Apoptag kit from Oncor and the Biotin-21 dUTP 3' end labeling kit from Clontech. The detection methods of the two kits differed in that the Oncor kit used digoxigenin dUTP and anti-digoxigenin-peroxidase and the Clontech used biotinylated dUTP and avidinperoxidase. Both used 3-3' diaminobenzidine (DAB) for final color development.

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Scanning electron microscopy of human iliac bone by a simple preparation method

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100158674 ◽

1990 ◽

Vol 48 (3) ◽

pp. 226-227

Author(s):

Toshihiko Takita ◽

Tomonori Naguro ◽

Toshio Kameie ◽

Akihiro Iino ◽

Kichizo Yamamoto

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Preparation Method ◽

Specimen Preparation ◽

Real Surface ◽

Public Attention ◽

Preparation Methods ◽

The Real ◽

Simple Preparation ◽

Scanning Electron

Recently with the increase in advanced age population, the osteoporosis becomes the object of public attention in the field of orthopedics. The surface topography of the bone by scanning electron microscopy (SEM) is one of the most useful means to study the bone metabolism, that is considered to make clear the mechanism of the osteoporosis. Until today many specimen preparation methods for SEM have been reported. They are roughly classified into two; the anorganic preparation and the simple preparation. The former is suitable for observing mineralization, but has the demerit that the real surface of the bone can not be observed and, moreover, the samples prepared by this method are extremely fragile especially in the case of osteoporosis. On the other hand, the latter has the merit that the real information of the bone surface can be obtained, though it is difficult to recognize the functional situation of the bone.

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Microscopy of porous ceramics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154160 ◽

1989 ◽

Vol 47 ◽

pp. 438-439

Author(s):

H. M. Kerch ◽

R. A. Gerhardt

Keyword(s):

Porous Ceramics ◽

Specimen Preparation ◽

High Porosity ◽

Ion Milling ◽

Forming Process ◽

Preparation Methods ◽

Pore Texture ◽

Proper Design ◽

And Function ◽

Function Information

Highly porous ceramics are employed in a variety of engineering applications due to their unique mechanical, optical, and electrical characteristics. In order to achieve proper design and function, information about the pore structure must be obtained. Parameters of importance include pore size, pore volume, and size distribution, as well as pore texture and geometry. A quantitative determination of these features for high porosity materials by a microscopic technique is usually not done because artifacts introduced by either the sample preparation method or the image forming process of the microscope make interpretation difficult.Scanning electron microscopy for both fractured and polished surfaces has been utilized extensively for examining pore structures. However, there is uncertainty in distinguishing between topography and pores for the fractured specimen and sample pullout obscures the true morphology for samples that are polished. In addition, very small pores (nm range) cannot be resolved in the S.E.M. On the other hand, T.E.M. has better resolution but the specimen preparation methods involved such as powder dispersion, ion milling, and chemical etching may incur problems ranging from preferential widening of pores to partial or complete destruction of the pore network.

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High-resolution scanning electron microscopy in biology

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100157607 ◽

1990 ◽

Vol 48 (3) ◽

pp. 14-15

Author(s):

Keiichi Tanaka

Keyword(s):

High Resolution ◽

Immunoglobulin M ◽

Metal Coating ◽

Biological Macromolecules ◽

Ultrahigh Resolution ◽

Preparation Methods ◽

Low Contrast ◽

Almost All ◽

Charging Effect ◽

Scanning Electron

With the development of scanning electron microscope (SEM) with ultrahigh resolution, SEM became to play an important role in not only cytology but also molecular biology. However, the preparation methods observing tiny specimens with such high resolution SEM are not yet established.Although SEM specimens are usually coated with metals for getting electrical conductivity, it is desirable to avoid the metal coating for high resolution SEM, because the coating seriously affects resolution at this level, unless special coating techniques are used. For avoiding charging effect without metal coating, we previously reported a method in which polished carbon plates were used as substrate. In the case almost all incident electrons penetrate through the specimens and do not accumulate in them, when the specimens are smaller than 10nm. By this technique some biological macromolecules including ribosomes, ferritin, immunoglobulin G were clearly observed.Unfortunately some other molecules such as apoferritin, thyroglobulin and immunoglobulin M were difficult to be observed only by the method, because they had very low contrast and were easily damaged by electron beam.

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Improving Sample Preparation Methods For Cannabis-Infused Edible And Topical Products

Planta Medica ◽

10.1055/s-0036-1578645 ◽

2016 ◽

Vol 82 (05) ◽

Author(s):

M Wilcox ◽

M Jacyno ◽

J Marcu ◽

J Neal-Kababick

Keyword(s):

Sample Preparation ◽

Preparation Methods ◽

Sample Preparation Methods

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A in Vivo Assay for Standardizing Heparin Preparations

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646810 ◽

1979 ◽

Vol 41 (03) ◽

pp. 576-582

Author(s):

A R Pomeroy

Keyword(s):

In Vitro Assays ◽

British Pharmacopoeia ◽

In Vitro Method ◽

Standard Preparation ◽

Reliable Estimation ◽

Assay Procedure ◽

Accuracy And Precision ◽

Heparin Preparation

SummaryThe limitations of currently used in vitro assays of heparin have demonstrated the need for an in vivo method suitable for routine use.The in vivo method which is described in this paper uses, for each heparin preparation, four groups of five mice which are injected intravenously with heparin according to a “2 and 2 dose assay” procedure. The method is relatively rapid, requiring 3 to 4 hours to test five heparin preparations against a standard preparation of heparin. Levels of accuracy and precision acceptable for the requirements of the British Pharmacopoeia are obtained by combining the results of 3 to 4 assays of a heparin preparation.The similarity of results obtained the in vivo method and the in vitro method of the British Pharmacopoeia for heparin preparations of lung and mucosal origin validates this in vivo method and, conversely, demonstrates that the in vitro method of the British Pharmacopoeia gives a reliable estimation of the in vivo activity of heparin.

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