Life Sciences Commons^™

Applications Of X-Ray Microanalysis To The Study And Conservation Of Ancient Glasses, S. Hreglich, M. Verita

Scanning Electron Microscopy

X-ray microanalysis can be successfully applied to the study of the chemical composition and weathering processes of ancient glass. The problems concerned with this kind of application are considered. A verification is conducted of the accuracy and sensitivity of this technique, which are sufficient to obtain useful information on technologies and raw materials used and consequently on the origin and dating of ancient glasses.

This analytical method also discloses meaningful data for the optimization of restoration and the choice of appropriate conservation operations.

The Use Of A Line Scan Ratemeter For The X-Ray Microanalytic Evaluation Of Membrane-Bound Histochemical Endproducts, Imre Zs.-Nagy, Valéria Zs.-Nagy

Scanning Electron Microscopy

Although X-ray microanalysis represents a useful tool for identifying electron dense histochemical end-products, quantitative microanalytic measurements are seriously hampered in the case of the activities of certain membrane-bound enzymes. For example, the electron histochemical methods revealing K⁺-dependent pNPPase activity result in a very fine, granular reaction product of lead phosphate. Therefore microanalytic, densitometric or similar evaluations of the reaction, even in semiquantitative terms are not practical by the usual procedures.

This paper describes a method of X-ray microanalysis of thick sections (0.5 μm) processed for K⁺-pNPPase, where a sufficient amount of lead is present for X-ray …

Calcium And Cystic Fibrosis, Godfried M. Roomans

Scanning Electron Microscopy

Cystic fibrosis (CF) is a generally lethal, congenital, genetic disease of unknown etiology. It is likely that a defective regulation of ion and water transport in exocrine glands and possibly also in other epithelial cells has a central role in the pathogenesis of this disease. Calcium has been implicated in the basic defect underlying CF because of findings of abnormally high calcium levels in some secreted fluids and some cells of CF patients.

Using X-ray microanalysis, we have demonstrated elevated calcium concentrations in cultured fibroblasts and in goblet cells of the bronchial epithelium of CF patients. A factor produced by …

The Electron Microscope Detection And X-Ray Quantitation Of Cations In Bacterial Cells, D. C. Sigee, M. H. El-Masry, R. H. Al-Rabaee

Scanning Electron Microscopy

Electron microscope autoradiography and X-ray microanalysis have been used for the detection and quantitation of cations in the bacterium Pseudomonas tabaci. These techniques differ in the information they provide (relating to either cation uptake or in situ levels), their applicability to different cations, their sensitivity and their spatial resolution. With uptake of ⁶³Ni²⁺, high resolution autoradiography (involving gold latensification and physical development) demonstrated a high degree of cation localisation to the central nucleoid area (glutaraldehyde-fixed cells) and within this to the constituent chromatin (acetic-alcohol preparations).

X-ray microanalysis of whole bacterial cells revealed the presence of substantial levels …

Application Of Chelex Standard Beads In Integrated Morphometrical And X-Ray Microanalysis, W. C. De Bruijn, M. I. Cleton-Soeteman

Scanning Electron Microscopy

Chelex ion exchange beads loaded with a known amount (18.3% weight percentage (w/w)) of platinum, have been co-embedded with a mouse peritoneal cell population. To establish the influence of the various deconvolution methods applied, upon the platinum concentration in cytoplasmic granules and erythrocytes these cross-sectioned beads are used as a standard. It is concluded that irrespective of the deconvolution method chosen 1) the Pt concentration inside the particles is identical when the particles and the co-embedded Chelex Pt standard, are analysed strictly under the same instrumental conditions 2) the Pt concentration outside the particle is zero, or virtually zero when …

Post-Mortem Storage Of Tissue For X-Ray Microanalysis In Pathology, Godfried M. Roomans, Joanna Wroblewski

Scanning Electron Microscopy

Possible alternatives to rapid freezing in liquid nitrogen of tissue for X- ray microanalysis of electrolytes at the cellular level were investigated. These alternatives might be used in cases where tissue becomes available for examination, e.g., at autopsy, but liquid nitrogen is not immediately available. Rat submandibular gland was used as a test tissue. Freezing of pieces of tissue in a conventional freezer at -80°C or even at -20°C retained the elemental distribution at the cellular level, and also retained the difference between a 'normal' and a 'pathological' (mimicked by an inject ion of a high dose of isoproterenol) situation. …

Integration Of X-Ray Microanalysis And Morphometry Of Biological Material, W. C. De Bruijn

Scanning Electron Microscopy

It was investigated how to extract both morphometrical and X-ray elemental information from scanning electron microscopical (SEM) or scanning transmission electron microscopical (STEM)-images and how to integrate these two information streams either on line or off-line after storage.

Cytochemical reaction products in cell organelles in ultrathin sections are the biological structures of interest. In such organelles four different situations can be met: morphologically the structures are homomorph or heteromorph; chemically the elements are distributed either homogeneously or heterogeneously. A new program has been proposed and described, which permits determination of both the area and the mean net-intensity value of chemical …

Applications Of Scanning Electron Microscopy And X-Ray Microanalysis In Inner Ear Pathology, M. Anniko, D. J. Lim, A. Sobin, R. Wróblewski

Scanning Electron Microscopy

Surface pathology of inner ear structures so far described in detail concern cochlear and vestibular hair cells and the stria vascularis. In man, surgical intervention into the inner ear is very uncommon and when performed is in general with the primary objective of destroying the diseased peripheral end organs. The vast majority of inner ear tissue available for use with scanning electron microscopy (SEM) is therefore obtained from animals.

The present paper reviews the progression of surface pathology caused by aminoglycoside antibiotics, acoustic overstimulation and in a guinea pig strain with genetic inner ear disease. The primary site of onset …

Cryoultramicrotomy And Electron Microanalysis Of Isolated Bovine Adrenal Chromaffin Cells, Richard L. Ornberg

Scanning Electron Microscopy

Instrumentation and techniques have been developed for the cryoultramicrotomy of isolated bovine adrenal chromaffin cells frozen with a liquid helium cooled copper block method. X-ray microanalysis and electron energy loss spectroscopy were used to measure both light and heavy element content of the adrenal storage granule, the chromaffin granule. Ultrathin freeze-dried cryosections usually have a fine compression which in cellular structure compresses the cytoplasm between organelles. Nuclei, chromaffin granules, and vacuoles are relatively free of compression. The mechanism for this distortion is not known al though static charge induced sticking to the knife may be the most probable cause.

The …

Problems Associated With The Preparation Of Cell Suspensions For X-Ray Microanalysis Highlighted By The Comparison Of Results With Those Obtained From Tissue Sections, A. Warley, M. D. Kendall, I. W. Morris

Scanning Electron Microscopy

Fully quantitative X-ray microanalysis of freeze dried frozen sections allowed the concentration of monovalent ions in the nuclei of mouse thymocytes in tissue sections to be compared with those from thymocytes which had been isolated by a simple preparation procedure. Isolated cells showed increased concentrations of Na and Cl. This was further investigated in the rat where the size of the thymus a 11 owed comparison between different isolation media using cells derived from the same animal. Use of autologous serum as the final suspending medium gave reproducible results, whereas with suspension in BSS, or 20% dextran the results were …

X-Ray Microanalysis In Cryosections Of Natively Frozen Paramecium Caudatum With Regard To Ion Distribution In Ciliates, M. Schmitz, R. Meyer, K. Zierold

Scanning Electron Microscopy

Cells of Paramecium caudatum were shock-frozen without pretreatment for cryoultramicrotomy and freeze-dried for subsequent X-ray microanalysis. Na, Mg, P, S, Cl, K, and Ca were detected in different amounts in several subcellular compartments. In particular, calcium was localized below the cell surface (pellicle). Trichocysts were found to contain significant amounts of Na in their base but not in the tip. Na, Mg, P, S, Cl, K, Ca were found in electron dense deposits within the lumen of the contractile vacuole. A small K concentration was found in the cytoplasm and in the mitochondria. X-ray microanalysis of the element distribution in …

Intracellular Localization Of Heavy Metals In Yeast By X-Ray Microanalysis, Ljerka Kunst, Godfried M. Roomans

Scanning Electron Microscopy

The intracellular localization of heavy metals in yeast cells was studied by means of energy-dispersive X-ray microanalysis. The yeast, Saccharomyces cerevisiae, was pretreated with phosphate and then loaded with different metal ions, by suspending the cells in salt solutions (Ni, Zn, Cd, Pb, Al and Cr). For the analysis, the cells were embedded in gelatin, rapidly frozen, and thin cryosections were cut on a dry knife.

A considerable uptake of divalent cations by the yeast cells was found to occur. The cations were bound to the polyphosphate granules localized in or close to the cell vacuoles. Immediately after phosphate …

Alterations Of The Intracellular Water And Ion Concentrations In Brain And Liver Cells During Aging As Revealed By Energy Dispersive X-Ray Microanalysis Of Bulk Specimens, Gy. Lustyik, I. Zs.-Nagy

Scanning Electron Microscopy

Age dependence of the intracellular concentrations of monovalent ions (Na+, K+ and Cl-) was examined in 1, 11 and 25-month-old rat brain and liver cells by using energy dispersive X-ray microanalysis. The in vivo concentrations of Na+, K+ and Cl- ions were calculated from two different measurements: The elemental concentrations were measured in freeze-dried tissue pieces, and the intracellular water content was determined by means of a recently developed X-ray microanalytic method, using frozen-hydrated and fractured bulk specimens as well as subsequent freeze-drying.

All the single monovalent ion concentrations and consequently, also the total monovalent ion content showed statistically significant …

Monte Carlo Electron Trajectory Calculations Of Electron Interactions In Samples With Special Geometries, Dale E. Newbury, Robert L. Myklebust

Scanning Electron Microscopy

Implementing a Monte Carlo simulation for application to electron sample interactions requires use of accurate treatments of elastic and inelastic scattering. In formulating a Monte Carlo simulation, careful testing must be carried out to ensure that the calculation yields sensible and useful results. A suitable testing procedure includes calculation of (1) electron backscatter coefficients as a function of atomic number, including any necessary adjustment of scattering parameters; (2) backscatter coefficients as a function of specimen tilt; (3) backscatter and transmission coefficients for thin foils; (4) backscattered electron energy distributions; (5) electron spatial distributions; and (6) x-rays, including x-ray depth distributions, …