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At least 19 recordsLinked to original sources
PubMed1976

Silicon in rat liver organelles: electron probe microanalysis.

Electron probe microanalysis of unfixed freeze-substituted rat liver tissue embedded in Spurr's low viscosity epoxy resin demonstrated the occurrence of Si as well as P, S, and Cl in the nucleus, nucleolus, mitochondria, and rough endoplasmic reticulum. Chemical analysis confirmed that the Si in the organelles did not originate from instrumental contaminants. This suggests that Si may be involved in the biochemistry of these subcellular organelles.

Cell Nucleolus↗
PubMed1979

Detection of iodine, sulphur and phosphorus in histological thyroid sections by using electron probe microanalysis.

Electron probe microanalysis for iodine, sulphur and phosphorus was performed in histological frozen sections from thyroid tissue of 5 patients undergone thyroid surgery for benign disease. Iodine seemed to be localized in the colloid of the thyroid follicles. Phosphorus localized in areas which corresponded with the epithelium of the follicles. Sulphur showed a strong association with iodine both in localization and in relative amounts. It was suggested that iodine and sulphur reflect the presence of thyroglobulin in the colloid of thyroid follicles.

Electron Probe Microanalysis↗
PubMed1977

Electron microscopy of human melanosomes in unstained, fresh air-dried hair bulbs and their examination by electron probe microanalysis.

Electron microscopy of unstained, fresh air-dried spreads of plucked human hair bulbs revealed relatively well preserved melanocytes and dense storage granules of melanin. Energy dispersive X-ray microanalysis of melanosomes and premelanosomes from black facial hair bulbs disclosed high peaks for potassium and sulfur, intermediate peaks for magnesium and calcium, and low but distinct ones for phosphorus and chlorine. No peaks for magnesium were found in the central portion of mature melanosomes, but at their edges and in premelanosomes conspicuous peaks for this element were obtained.

Electron Probe Microanalysis↗
PubMed1977

Electron probe microanalysis: its present, its future.

Electron probe microanalysis (EPM) is a method of elemental ultramicroanalysis based on the spectrometry of the characteristic X rays which are emitted when a target sample is excited by an electron beam. In the same sample many more elements (from carbon and up in the periodic table) in much smaller volumes (less than 1 micronm3 or 10(-15) liter) can be analyzed with EPM than with any other ultramicroanalytical method. Quantitation down to 10(-15) g is relatively easy. Any application of EPM in biology depends on the development of suitable methods for biological sample preparation. Liquid droplets of 10(-11)-liter volumes are routinely analyzed. Elemental content in isolated cells can be quantitated. The analysis of cellular, extracellular, and intercellular content in the same preparation is in sight: a general method for the analysis of diffusible elements in different compartments in tissue relies on the manipulation of frozen hydrated tissue near liquid nitrogen temperature. Localization in the same preparation of several organic compounds at high resolution will be possible by use of appropriate tags. All fields of microphysiology are likely to benefit from this new discipline.

Cells↗
PubMed1976

A combined scanning and transmission electron microscopic study and electron probe microanalysis of human pineal acervuli.

Untreated, decalcified and trypsinized acervuli from human pineal bodies were studied with the scanning and transmission electron microscope as well as by electron probe microanalysis. The mulberry-like acervuli are composed of a various number of spherical lobes (135-800 mum) between which clustered groups of globuli (4--14 mum in diameter) are observed. The acervular lobes are very probably formed by an aggregation of these globuli. Small round particles 125--500 A in diameter are observed on the surface of the pineal concretions. These are not influenced by either decalcification or trypsin treatment. The acervular mineral corresponds morphologically to hydroxyapatite. The electron probe microanalysis reveals the existence of calcium and phosphorus as main components of the acervuli. Small quantities of magnesium and strontium were also detected.

Aged↗
PubMed1975

Scanning electron microscopy and electron probe microanalysis of calcified alpha-elastin coacervates.

The uptake of calcium and phosphorus from a serum calcification medium by coacervated alpha-elastin was studied by electron probe microanalysis and scanning electron microscopy. Calcium and phosphorus were bound by the coacervate in ratios similar to that of hydroxyapatite. A significant difference was observed in the secondary electron image of the coacercules from the serum during calcification of the coacervate.

Animals↗
PubMed1978

Quantitative electron probe microanalysis of biological thin sections: the use of stem for measurement of local mass thickness.

A method for performing quantitative electron probe microanalysis on ultrathin (less than 30 microgram/cm2) biological samples is described and evaluated. The technique is based on a measurement of the characteristic peak count rate and the degree of beam attenuation as the primary electron beam passes through the sample. Using this method it is possible to measure the concentration of a given element such as sodium in sections ranging in mass-thickness from several microgram/cm2 up to 30 microgram/cm2 with an accuracy of better than 10%. For sections having a mass thickness of approximately 11 microgram/cm2 the minimum detectable concentration for sodium was found to be 20 mmolar or 4 X 10(-2) wt.%. The interaction of the electron beam with the sample is also discussed with emphasis on characterizing the variation in sample mass with radiation dose.

Electron Probe Microanalysis↗
PubMed1992

Comparison of cryopreparation techniques for electron probe microanalysis of cells as exemplified by human erythrocytes.

Erythrocytes in human blood were used to evaluate the reliability of cryopreparation techniques for electron probe X-ray microanalysis of biological cells and tissues. The elemental content determined by X-ray microanalysis of ultrathin freeze-dried cryosections was found to be consistent with data known from the literature. Considerable redistribution of the intracellular elemental composition was found after freeze-substitution as well as after freeze-drying followed by resin embedding. Two conclusions are drawn from this study: 1. Erythrocytes in human blood are a suitable reference specimen for evaluation of specimen preparation techniques for microanalysis. 2. At present, freeze-dried cryosections are the most reliable specimen type for quantitative electron probe microanalysis of cells.

Cryopreservation↗
PubMed1977

Electron probe microanalysis of the chemical elemental content of human follicular fluid.

Follicular fluid samples were obtained by puncturing follicles of ovaries in situ from patients undergoing laparotomy. Sodium, potassium, chloride, magnesium, calcium, phosphorus, and sulfur concentrations measured by electron probe microanalysis were similar to those of blood, with minimal differences. This suggested that culture media in which these electrolytes are added in concentrations similar to those of serum are appropriate for culture of the human oocyte.

Calcium↗
PubMed1978

Electron probe microanalysis of red blood cells. II. Cation changes during maturation.

To understand the sequence of maturation of membrane transport and hemoglobin production during erythropoiesis, we have measured the K, Na, and Fe content in single mature red blood cells and bone marrow cells of dog using electron probe microanalysis (EPMA). Mature red blood cells of dog are low in potassium (LK) and high in sodium. These cells are derived from erythroblastic stem cells, which are high in potassium (HK) and low in sodium. This change from HK stem cells to LK red cells occurs in the marrow. The ratio of K/Na was found to be less than 0.2 independent of Fe/(K + Na) in circulating red cells. However, a significant number of marrow cells had both low K/Na and low Fe/(K + Na). We conclude that the changes in cation transport properties responsible for the conversion of HK to LK cells occur before the synthesis of hemoglobin in at least some marrow cells.

Animals↗
PubMed1977

Electron probe microanalysis in the study of gallstones.

Detailed information on the structure and composition of gallstones was obtained using an electron probe microanalyser in conjunction with the other methods. Gallstones were studied layer by layer without greatly disturbing the arrangement of the materials present. Elements, including trace elements such as copper, iron, and manganese, were identified and their distributions mapped. The range of the method was extended to determine the character and distribution of certain chemical groups present by treating sections of gallstone with reagents which contained easily detected elements. The nature of the bonding of the sulphur in the stones was studied by examining the sulphur-X-ray spectrum. Pigmented sulphur-containing deposits were found to contain sulphur in a low valence state but taurine conjugates and the sulphate groups of mucosubstances were not detected. Microcrystalline apatite present in the stones contained some manganese and seemed to be implicated in the absorption of the low valence sulphur compound and in the nucleation of some stones.

Calcium↗
PubMed1977

Identification of stainless steel welding fume particulates in human lung and environmental samples using electron probe microanalysis.

Open lung biopsy specimens from two welders and air samples from their workplace environments were examined with the electron probe microanalyzer. X-ray analysis showed that the majority of particles found in the lung tissue from both workers and in the air samples to be composed of varying amounts of iron, chromium, manganese and nickel, the major components of some types of stainless steel. Based upon these analyses, it was concluded that the majority of the particles in both biopsy specimens were a result of the workplace environment.

Air Pollutants, Occupational↗