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At least 1,747 records · Page 97Linked to original sources
PubMed1986

Elemental content of anagen hairs in a normal Caucasian population studies with proton induced X-ray emission (PIXE).

The elemental content of anagen hair fibers in a Caucasian population of healthy females and males in the age range 10-69 years was performed to constitute a baseline for further studies of pathological conditions. Proton induced X-ray emission (PIXE) analyses were performed on single hair fibers in triplicate from 103 individuals in order to determine sulfur, zinc, calcium, and chlorine content. The hair fibers were all anagen hairs collected from a site little influenced by genetic and hormonal influences 1.5 cm above the right ear of the probands. An area 5-8 mm from the follicle bottom was chosen for the analysis in all cases to minimize effect of hair-do contamination. The average sulfur content was 0.049 g/g and the average zinc content 170 micrograms/g. These results were not significantly influenced by chloroform/ethanol rinsing before analysis. The calcium and chlorine contents were 330 micrograms/g and 0.0033 g/g respectively. The latter data are expected to be more seriously influenced by external factors (e.g., contamination) than sulfur and zinc. No correlation between elemental concentration and sex was found for sulfur and zinc in the present material. PIXE analysis of single hair fibers yields valuable information on the elemental composition of hair fibers and can be rapidly and efficiently performed after simple mounting procedures.

Adolescent↗
PubMed1985

Electron microscopy and microprobe analysis of dialysis contaminants.

A migration of plastic particles from haemodialysis circuit to blood has been recognized to be cause of storage inflammation. Its origin from segments of silicone tubing has been demonstrated by in vivo and in vitro experiments. A similar finding with a peculiar histology picture has been observed in patients who used only PVC and PU-PVC tubing. In this case too microprobe analysis revealed the presence of silicon (Si) in fibril inclusions of liver and spleen cells. TEM, SEM and EDS of cuprophane dialyzer perfusates filtered through Nuclepore revealed the presence of particles with an intense Si Ka. The release from the dialyzer of silicon containing contaminants seems to be an additional risk for uremic patients.

Adult↗
PubMed1985

Ultrastructural modifications of proteoglycans coincident with mineralization in local regions of rat growth plate.

We carried out histochemical and electron-microscopic studies to examine the relationship between mineral deposition and changes in the organization of proteoglycans during mineralization in the cartilaginous growth plate of the rat. To preserve the distribution and organization of proteoglycans in the extracellular matrix and to stain proteoglycans, acridine orange was included in the solutions that were used for fixation and demineralization. In undecalcified sections, mineral crystals that initially appeared at the level of the penultimate hypertrophic chondrocyte grew into dense, spherical mineral clusters, roughly one micrometer in diameter, in the longitudinal septa of the lowermost hypertrophic zone. Following the removal of mineral with EDTA in the presence of acridine orange, proteoglycan structures with a characteristic rosette-like architecture were revealed within the matrix of the longitudinal septa of the lower hypertrophic zone. The location of these rosette-like proteoglycan structures was identical to that of the dense, spherical mineral clusters in the undemineralized controls, and they were remarkably similar in morphology and size. In the electron micrographs stained with uranyl acetate and lead citrate, the greatly increased density of the rosette-like structures and large diameter of the proteoglycan structures located in mineral clusters contrasted sharply with the slender strands of more faintly stained proteoglycan that was diffusely distributed throughout most of the extracellular matrix. X-ray microprobe analysis for sulphur confirmed the existence of proteoglycans in the rosette-like structures and demonstrated that the concentration of proteoglycans was selectively increased in these regions. The cores of the metaphyseal calcified cartilage also exhibited rosette-like proteoglycan structures, which before demineralization were totally obscured by the diffuse, dense homogeneous deposition of mineral. Without stabilization of the proteoglycans in the extracellular matrix with acridine orange, the rosette-like proteoglycan structures could not be demonstrated. These results clearly indicate that there is a selective increase in the concentration of proteoglycans in exactly the same regions where mineral clusters are formed in the hypertrophic zone of the cartilaginous growth plate.

Acridine Orange↗
PubMed1985

Scanning electron microscopy methodology for study of the pathophysiology of calcification in bioprosthetic heart valves.

Scanning electron microscope (SEM) morphologic analysis combined with energy dispersive characteristic X-ray (EDX) microprobe analysis provides insight into the mechanisms associated with disease-related crystal formation in biological materials. SEM and EDX were employed in analyzing specimens which were embedded in standard fashion in glycolmethacrylate. The specimen surfaces under electron microscope investigation resulted from microtomy used in the preparation of reference light microscope histological sections; thus histology served as a direct reference for the SEM and EDX analyses. The particular application of these methods was in the study of bioprosthetic heart valve calcification, largely responsible for clinical failure of these heart valve substitutes. To simulate the clinically observed mineralization processes, glutaraldehyde-pretreated porcine heart valve leaflets were implanted subcutaneously in rats and subsequently removed at various time intervals from 1 to 56 days. Also, to address the hypothesis that the calcification process generates crystalline materials analogous to those in bone, EDX data obtained from pure hydroxyapatite were compared with the embedded tissue results. Further, EDX results were compared with data obtained by chemical analysis of the bulk specimens to assess the validity of the electron microscope technique.

Animals↗
PubMed1985

Wave-length dispersive microprobe analysis of coated samples of bulk tissues.

Hypertrophic scars contain highly pleomorphic cells, including many from the erythrocytic series which have been extravasated. The conventional visual mode of SEM cannot distinguish the cell types with certainty except in the case of typical biconcave disc-shaped erythrocytes. Microprobe elemental analysis might be used to differentiate one type from another on the basis of iron and possibly phosphorus (for nucleated cells). Using coated specimens (gold or gold-palladium) precludes simultaneous visual mode SEM with EDX because of energy line interference with phosphorus and other elements. However, wave-length dispersive analysis offers minimal or no interference, and a coated specimen offers the use of a simultaneous visual mode. We wished to determine if useful elemental data could be obtained from specimens previously prepared only with the purpose of SEM mode studies. Therefore they were not prepared according to contemporary optimal methods. Analysis demonstrates that one group of cells contains 45% or more (dry weight concentration, absolute) iron as opposed to markedly low values in other cell types. Values for phosphorus do not appear essentially different among the cell types except in the case of standard erythrocytes where it is very low. Calcium and sulfur content was also examined. Sulfur might be useful in identifying another cell type in the hypertrophic scar. Using cells and matrix in developing deer antler for control values, the ratio of calcium to phosphorus found in the mineralizing matrix was essentially the predicted value. It is concluded, therefore, that even with a substantially heavy coating of gold, values for the elements tested (Fe, P, Ca, S) are not seriously compromised.

Animals↗
PubMed1979

Electron probe analysis of muscle and X-ray mapping of biological specimens with a field emission gun.

Recent electron probe analytic studies of freeze-dried cryosections of vascular smooth and vertebrate striated muscle are reviewed. The results show that the sarcoplasmic reticulum of striated muscle is not in ionic communication with the extracellular space. Vacuolation by hypertonic solutions and fatigue involves the T-tubule system. The high calcium content of the terminal cisternae of the resting muscle has been quantitated in situ. In smooth muscle, the high Cl content is distributed in the cytoplasm, and mitochondria in rabbit portal vein smooth muscle cells do not contain high concentrations of calcium. Mitochondrial calcium loading in the form of granules is generally due to fiber damage. Nuclear and mitochondrial composition in situ has been quantitated and compared to the composition of the cytoplasm of the same cells. Preliminary phosphorus x-ray maps of smooth muscle show the feasibility of this approach in defining the composition of organelles in thin cryosections. The use of x-ray maps at intermediate resolution is illustrated with tropomyosin paracrystals labelled with Hg-containing dye at the thiol residues. Mercury x-ray maps of such paracrystals show the 40nm periodicity of the thiol groups and their Fourier transforms contain information to a spatial resolution of 10-20nm.

Animals↗
PubMed1979

Intracellular electrolyte concentrations in epithelial tissue during various functional states.

The scanning electron microscope together with an energy dispersive system was used to quantify intracellular elemental concentrations of transporting epithelial cells under a variety of experimental conditions. In the frog skin, the Na transport pool is comprised of the intracellular compartments of all vital cells in the different cell layers, except the mitochondria rich cells. The Na content of this transport pool exchanges easily with the epithelial (outer) bathing solution. Vasopressin increases the Na permeability of the corial cell barrier. Proximal and distal tubular cells of the rat kidney show differences in the pattern of intracellular element concentrations. The distal tubular cell is more resistant to 20 min of ischemia than the proximal cell. The changes in intracellular electrolyte concentrations following 60 min of ischemia are reversible after reperfusing the kidney with blood for 60 min. In the cells of the frog skin and rat kidney, Na and K were equally distributed between the cytoplasm and the nucleus. Differences exist for P, Cl and dry weight.

Amiloride↗
PubMed1984

[Gingival pigmentation caused by dental amalgam. An ultrastructural study].

The aim of this investigation is the ultrastructural analysis of biopsies of human gingiva pigmented by the metallic deposits from dental amalgam. The size, the nature and the distribution of the particles are studied by light and electron microscopy and by energy dispersive spectrometry (EDS). Fragments and particles of different size and composition are observed. No traces of mercury are detected in any examined samples. In contrast, very fine grains (0.01 to 0.05 microns in diameter) of a silver compound are observed to be preferentially bound to intracellular membranes and to extracellular structural components. Tissue modifications in the gingival epithelium as well as in the connective tissue can accompany the pigmentation phenomenon. The different metabolic pathways of the metals diffusing from the amalgams are discussed.

Biopsy↗
PubMed1982

Scanning electron microscopy and EDX analysis of exocrine and endocrine gland cells of rat pancreas surface-etched in an oxygen plasma.

Pancreas, double-fixed in glutaraldehyde and osmium tetroxide and embedded in epoxy resin was cut into sections 0.5-1 micron thick. The sections were surface-etched in an oxygen plasma produced by exciting oxygen with a radio frequency generator. Structural components of exocrine and endocrine cells were morphologically investigated in the secondary electron image mode of the SEM. Moreover, in order to identify some cell components such as endocrine granules, the morphological image obtained of the etched surface by the SEM were compared with those seen in a TEM, using the serial sections from the same tissue block and at the same cellular level. For a microanalytical investigation, tissues were fixed with glutaraldehyde alone. The structural components of exocrine and endocrine cells were analyzed by SEM/EDX. A better resolution under the SEM was obtained of 0.5-0.8 micron thick sections after surface-etching in an oxygen plasma for 1 minute. Intracellular structures such as nuclear membranes, nucleolus, mitochondria, rough endoplasmic reticulum and zymogen granules were readily identifiable. Moreover, the internal structure of organelles such as cristae of mitochondria was recognized. In the serial sections, the mode of arrangement of intracellular structures in the SEM was well consistent with those in the TEM. The peaks of phosphorus, sulphur and calcium were clearly detected from the intracellular components such as nucleolus, nuclear membranes and secretory granules.

Animals↗
PubMed1982

Multi-method analysis of calcium localization in the secretory ameloblast.

X-ray micro-analysis and electron energy loss analysis were used to confirm cytochemical localization by potassium pyro-antimonate of calcium in secretory ameloblasts. Neither intercellular calcium concentration between ameloblasts nor over-all calcium levels of the enamel organ were lowered during a period of inhibition of enamel mineralization by injected fluoride. Calcium concentrations in mitochondria and secretory granules were reduced.

Ameloblasts↗