Engery-filtering transmission electron microscopy of biological specimens.

By energy-filtering transmission electron microscopy (EFTEM) electrons can be separated by their energy losses. An electron-energy filter, added to the microscope column allows the measurement of the energy distribution of transmitted electrons that have lost energy (< 2,000 eV, with an energy resolution of approximately 1 eV). These filtered electrons, recorded either as a spectrum or as an image, are composed of two parts superimposed on top of each other: (a) the unspecific energy-loss population (= the continuum) and (b) the specific element-related energy-loss population (= the edges).

Electron energy-loss spectroscopical and image analysis of experimentally induced rat microliths. II.

Following a microlith-inducing diet of ethylene glycol plus ammonium chloride, intraluminal and intracellular crystals are observed in aldehyde-fixed rat proximal and distal tubule cells by light and electron microscopy. Qualitative, in-situ analysis with electron-probe X-ray microanalysis (EPMA) of these intraluminal and intracellular crystals shows the presence of calcium, a trace of magnesium, some chlorine and the virtual absence of phosphorus and sulphur. Electron energy-loss spectroscopical element (EELS) analysis and electron-spectroscopic imaging (ESI) confirm, at both sites, the presence of calcium.

Accumulation of iron in erythroblasts of patients with erythropoietic protoporphyria.

We have studied the iron metabolism in nine patients with erythropoietic protoporphyria (EPP) and three patients with sideroblastic anaemia (SA). All, except one EPP patient were iron deficient. The SA patients had a secondary haemochromatosis.

Correspondence analysis for quantification in electron energy loss spectroscopy and imaging.

Electron energy loss spectroscopy (EELS) is a technique to investigate the physical properties of material. Using this technique it is possible to detect the presence of a specific element in a specimen. When used in combination with an electron microscope, energy filtered images may be obtained, which in principle may be used to quantify the local element concentration.

A quantitative immunoelectronmicroscopic study on soluble, membrane-associated and membrane-bound lysosomal enzymes in human intestinal epithelial cells.

We have used quantitative immunoelectronmicroscopy to compare the in situ localization of acid alpha-glucosidase, lysosomal acid phosphatase, beta-hexosaminidase and glucocerebrosidase in intestinal epithelial cells of the human duodenum. Differences between these four lysosomal enzymes were observed with respect to their presence at the apical cell surface. Transport to the apical membrane seems to be a more important intracellular route for lysosomal acid phosphatase and acid alpha-glucosidase than it is for beta-hexosaminidase.