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Full-Text Articles in Life Sciences
Freeze-Drying And Related Preparation Techniques For Biological Microprobe Analysis, Romuald Wróblewski, Joanna Wróblewski, Matti Anniko, Lars Edström
Freeze-Drying And Related Preparation Techniques For Biological Microprobe Analysis, Romuald Wróblewski, Joanna Wróblewski, Matti Anniko, Lars Edström
Scanning Electron Microscopy
An X-ray microanalytical and morphological investigation has been carried out on rapidly frozen, freeze-dried or freeze-substituted tissues. A comparison was made between different embedding and polymerisation procedures following freeze-substitution and freeze-drying. The investigation also included an analysis of specimens infiltrated, embedded and polymerised by ultraviolet irradiation at low temperatures with Lowicryl HM20. The morphological preservation of Lowicryl embedded tissue was adequate for the identification of different cell structures like nuclei, mitochondria, lysosomes and different types of endoplasmic reticulum. X-ray microanalytical investigation of low temperature embedded material displayed an elemental composition of cells and organelles similar to that found in freeze-dried …
Two Opposing Theories Of The Cell: Experimental Testing By Cryomethods And Electron Microscopy, L. Edelmann
Two Opposing Theories Of The Cell: Experimental Testing By Cryomethods And Electron Microscopy, L. Edelmann
Scanning Electron Microscopy
A main controversial issue in cell biology concerns the molecular mechanism responsible for K+ accumulation in living cells and Na+ exclusion from them. The alternative theoretical descriptions of these phenomena are based on different assumptions about the physical state of cellular Na+, K+ and H2O. In this article it is shown with striated muscles how cryomethods and microanlytical electron microscopy may be used to test the opposing theories. It is concluded that these methods may yield more realistic informations about the physical state of cellular K+ and Na+ than measurements with …
Low Temperature Embedding, E. Carlemalm, W. Villiger, J. -D. Acetarin, E. Kellenberger
Low Temperature Embedding, E. Carlemalm, W. Villiger, J. -D. Acetarin, E. Kellenberger
Scanning Electron Microscopy
The Lowicryl resins K4M and HM20 are methacrylate/acrylate based formulations which can re used for embedding biological material at low temperature in conjunction with either the progressive lowering of temperature (PLT) technique or with freeze-substitution. The resins are applicable over a very extended temperature range, approximately 210°K to 340°K. Even lower temperatures down to ca. 190°K can be reached with two new resins, K11M and HM23. Test embeddings of unfixed material after freeze-substitution have given promising results which could re useful for imnunocytochemical labeling. Lipid extraction is small or absent when the two new resins are used in combination with …
Freeze Substitution And Low Temperature Embedding, B. Humbel, M. Müller
Freeze Substitution And Low Temperature Embedding, B. Humbel, M. Müller
Scanning Electron Microscopy
The problems of conventional EM-preparation techniques based on chemical fixation may be overcome to a considerable extent by freeze substitution techniques. Although at present substitution cannot be performed at sufficiently low temperatures to prevent the recrystallization of vitrified aqueous specimens, thin sectioned biological samples show an improved information density. If freeze-substitution is combined with conventional embedding above 273 K (Epon/Araldite, Spurr's resin) the substituting organic solvent must contain stabilizing agents such as osmiumtetroxide, glutaraldehyde or uranylions. In combination with low temperature embedding procedures (Lowicryl) completely unfixed samples are obtained, which are suitable for immunolabelling and electron spectroscopic experiments. Water in …