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PubMed1992

Postvaccinal sarcomas in the cat: epidemiology and electron probe microanalytical identification of aluminum.

An increase in fibrosarcomas in a biopsy population of cats in the Pennsylvania area appears to be related to the increased vaccination of cats following enactment of a mandatory rabies vaccination law. The majority of fibrosarcomas arose in sites routinely used by veterinarians for vaccination, and 42 of 198 tumors were surrounded by lymphocytes and macrophages containing foreign material identical to that previously described in postvaccinal inflammatory injection site reactions. Some of the vaccines used have aluminum-based adjuvants, and macrophages surrounding three tumors contained aluminum oxide identified by electron probe microanalysis and imaged by energy-filtered electron microscopy. Persistence of inflammatory and immunological reactions associated with aluminum may predispose the cat to a derangement of its fibrous connective tissue repair response, leading to neoplasia.

Aluminum↗
PubMed1996

In vitro characterization of enamel epithelium and pulp cells in mouse tooth germs.

Mixed cell populations consisting of enamel epithelium and pulp cells obtained from 18-day embryonic mouse tooth germs were cultured in vitro. Epithelial cells and pulp cells were also cultured individually and examined. Isolated cells were cultured in alpha-MEM supplemented with 10% fetal bovine serum for up to four weeks and examined morphologically using histological procedures including immunostaining, light and electron microscopy, and electron probe microanalysis. The pulp cells proliferated and differentiated in the absence of epithelium, but the number of epithelial cells showed a strong dependence on the pulp cells. Pulp cells showing fibroblastic morphology in the mixed culture gradually became elliptical, and eventually transformed into spherical cells surrounded by a calcified extracellular matrix. Alkaline phosphatase (ALPase) activity was expressed on the pulp cells prior to calcification of the extracellular matrix, as shown by von Kossa's and alizarin-red staining. Calcification deposition, which is closely associated with thick banded type-I collagen fibrils, was shown to be composed of calcium and phosphorous using electron probe microanalysis. Type-I collagen immunoreactivity was detected on the extracellular matrix after two weeks of culturing. The present results show that the proliferation and differentiation of pulp cells, and subsequent calcification of the extracellular matrix occur in the presence or absence of epithelial elements, but that the proliferation of epithelial cells depends on the presence of pulp cells.

Ameloblasts↗
PubMed1997

Backscattered electron imaging of cultured cells: application to electron probe X-ray microanalysis using a scanning electron microscope.

We report a simple method to study the elemental content in cultured human adherent cells by electron probe X-ray microanalysis with scanning electron microscopy. Cells were adapted to grow on polycarbonate tissue culture cell inserts, washed with distilled water, plunge-frozen with liquid nitrogen and freeze-dried. Unstained, freeze-dried cultured cells were visualized in the secondary and backscattered electron imaging modes of scanning electron microscopy. With backscattered electron imaging it was possible to identify unequivocally major subcellular compartments, i.e. the nucleus, nucleoli and cytoplasm. X-ray microanalysis was used simultaneously to determine the elemental content in cultured cells at the cellular level. In addition, we propose some improvements to optimize backscattered electron and X-ray signal collection. Our findings demonstrate that backscattered electron imaging offers a powerful method to examine whole, freeze-dried cultured cells for scanning electron probe X-ray microanalysis.

Animals↗
PubMed1991

Absence of aluminium in Alzheimer's disease brain tissue: electron microprobe and ion microprobe studies.

Brain tissue from the frontal cortex and hippocampal formation, taken at autopsy or biopsy from 7 patients with Alzheimer's disease, was studied by two methods of microanalysis. One case of Down's syndrome was also studied. Electron probe microanalysis of the frontal cortex and Ammon's horn of the hippocampus showed no aluminium in the various cell organelles, especially in the lysosomes, although some aluminium was found in a few contaminating dusts. Ion microscopy, a method of extremely high sensitivity, also showed the absence of an aluminium signal.

Adult↗
PubMed1986

Ca-pools involved in the regulation of cardiac contraction under positive inotropy. X-ray microanalysis on rapidly-frozen ventricular muscles of guinea-pig.

Electron probe microanalysis of rapidly-frozen small ventricular trabeculae of guinea-pig demonstrates that the distribution of total intracellular calcium varies under positive inotropy depending on the type of inotropic intervention. The sarcoplasmic reticulum (SR) (or part of it) localized at the level of the z-lines reveals high calcium accumulation at the end of diastole whenever a stimulus is followed by a contraction with a short time to peak of force. After paired pulse stimulation, only this cell compartment accumulates calcium at the end of diastole. Since this cell compartment is "Ca-empty" in muscles frozen during contraction, SR is considered to be the source of activator Ca. In several cases of inotropy (after application of ARL, caffeine or after lowering the extracellular Na+ concentration), calcium is also detectable on the mitochondria, suggesting that these organelles participate in slow regulation of cytosolic calcium. In some cases, total calcium located on the sarcomeres is increased. The interpretation of this finding is intriguing and requires the assumption of supplementary cytosolic Ca-sinks as yet unknown.

Animals↗
PubMed1976

Pulmonary mineral dust. A study of ninety patients by electron microscopy, electron microanalysis, and electron microdiffraction.

The results of a study of 90 patients are presented. Intrapulmonary mineral deposits were characterized by electron diffraction and electron probe microanalysis. Using this method, pneumoconioses may be distinguidhed from other pneumopathies. In cases of pneumoconiosis, there exists a specific relationship between the etiology of the dust exposure and the crystallographic characteristics of the intrapulmonary deposits. The nature of the deposits may be indicative of a specific type of pneumoconiosis. This method is particularly useful in differentiating between asbestos bodies and ferruginous bodies. The value of the method in general and its importance in the study of pneumoconiosis are discussed.

Asbestos↗
PubMed1974

Elemental analysis of asbestos fibers by means of electron probe techniques.

The identification and characterization of microparticles has become an important field of study in recent years due to their presence in the environment and association with pathogenesis. Asbestos fibers have been intensively studied for these reasons. Since conventional microscopy has not provided unique identification of these materials, electron probe microanalysis, which yields chemical data, has been utilized in conjunction with other techniques to provide the necessary answers.The options now available to undertake electron probe analysis are discussed with relation to their utilization for microparticle analyses. Two types of electron sources are available, thermionic and field emission. The x-ray spectroscopy requires the use of either wavelength-dispersive focussing crystal spectrometers or an energy-dispersive Si(Li) x-ray detector. Data are presented to demonstrate the feasibility of asbestos identification by using modified raw data obtained with a scanning electron microscope and energy-dispersive x-ray spectrometer. Further, the extension of the technique to other microparticle identification problems is discussed.

Air Pollutants↗
PubMedDate not supplied

Estimation of the copper-iron correlation in the liver under experimental conditions. A microscopic and microchemical study.

Liver obtained from copper-intoxicated rats was studied by electron microscopy and electron probe microanalysis. Large ultrastructural disorders in liver cells appeared at the level of lysosomes and mitochondria. Diffuse and aggregate copper granules were observed in the entire cell, but mainly in pericentrolobular and periportal zones. Probe analysis revealed an increased copper deposit, particularly during the chronic copper intoxication, and a very high concentration of iron gradually accumulated.

Animals↗
PubMed1979

X-ray analysis of pathological calcifications including urinary stones.

Electron-probe microanalysis (EPM) is an ideal technique with which to study biological calcification. It is particularly effective in identification of crystalline or non-crystalline deposits of minute size in tissues, and in detecting artifacts which may occur during tissue processing. Human aorta, aortic valves, tumours, joint fluid, and calculus specimens were analyzed via scanning electron microscopy (SEM), EPM, transmission electron microscopy (TEM), and selected-area electron diffraction (ED). Crystals found in the specimens were definitively identified by combined SEM-EPM. It is apparent that EPM is an invaluable tool that will potentially improve the acuity of 'in house' laboratory diagnosis of many pathological calcifications.

Aorta↗
PubMed1998

Electron microscopic observations and X-ray microanalysis of a multinucleated giant cell.

Giant cells and macrophages play important roles in defence and in reparative functions of the body. This paper describes a giant cell and macrophage present in an inflammatory mass in the temporal bone. X-ray microanalysis performed at the ultrastructural level revealed the presence of a very high iron content in the electron dense precipitates observed in both types of cells. The high iron content is probably due to phagocytosed haemosiderin, a breakdown product of free haemoglobin since there was evidence of haemorrhage present in the biological sections. As the tissue was chemically fixed, it also demonstrates that there is still a place for electron probe microanalysis in tissues (including archived specimens) which have undergone chemical fixation.

Adult↗
PubMed1998

Ultrastructural organization and microanalysis studies of deciduous enamel crystallites in regional odontodysplasia (RO).

The ultrastructural organization and chemical components of enamel crystallites in two deciduous teeth affected by RO, an uncommon developmental condition giving the tooth a ghost-like appearance, were investigated by scanning and transmission electron microscopy, X-ray diffraction, electron probe microanalysis and Fourier transform improved microspectroscopy. Pathologic mineralizations involving prismatic structures, which affected the size, shape and stoichiometric structure of crystallites and led to enhanced Mg/Ca and Na/Ca ratios and crystal defects, were observed. Local circulatory disorders may have caused this developmental anomaly.

Child, Preschool↗
PubMed1995

Chronic copper intoxication due to ingestion of coins: a report of an unusual case.

We report an unusual case of acute copper intoxication in a patient who died after swallowing more than 700 coins mainly of 1p and 2p denomination. At autopsy the liver showed fibrosis and extensive copper deposition was demonstrated in the histological sections. Electron probe microanalysis also confirmed the presence of copper in the hepatic tissue.

Copper↗
PubMed1987

The mechanism of acute cytotoxicity of triethylphosphine gold(I) complexes. I. Characterization of triethylphosphine gold chloride-induced biochemical and morphological changes in isolated hepatocytes.

Triethylphosphine gold complexes are effective therapeutic agents used for the treatment of rheumatoid arthritis. Many of those molecules are also highly cytotoxic in vitro and can inhibit DNA and protein synthesis. Preliminary experiments have indicated that triethylphosphine gold chloride (TEPAu) may induce the peroxidative decomposition of cellular membrane lipids. The purpose of these investigations therefore was to evaluate the role of lipid peroxidation in the mechanism of acute cytotoxicity of a gold(I) coordination complex, TEPAu, and to examine the early morphological and biochemical changes induced by TEPAu in suspensions of freshly isolated rat hepatocytes. TEPAu caused a rapid loss of cell viability at concentrations above 25 microM which was significantly different from that of control by 60 min and complete by 180 min of incubation. TEPAu also depleted cells of reduced glutathione (GSH) and increased the formation of malondialdehyde (MDA) by 60 min. Incubation of cells with either of the antioxidants, N,N'-diphenyl-p-phenylenediamine (DPPD) or promethazine blocked the formation of MDA but did not alter the time course of cell death or GSH depletion induced by TEPAu. TEPAu also caused a decrease in cellular NADPH and NADH by 10 min. Electron microscopy of hepatocytes exposed to TEPAu revealed early (5 min) formation of flocculent electron-dense precipitates within condensed mitochondria. These changes characteristically preceded cell death. Energy-dispersive electron-probe microanalysis indicated that the electron-dense precipitates did not contain detectable amounts of gold. TEPAu also caused a concentration-dependent decrease in cellular ATP and oxygen consumption in isolated rat hepatocytes. These data suggest that lipid peroxidation, as indicated by the formation of MDA, is probably not a major mechanism by which triethylphosphine gold complexes lethally injure cells. These data, therefore, suggest that mitochondria may be target organelles in TEPAu-induced toxicity to isolated rat hepatocytes.

Animals↗
PubMed1988

Collagen expression, ultrastructural assembly, and mineralization in cultures of chicken embryo osteoblasts.

A newly defined chick calvariae osteoblast culture system that undergoes a temporal sequence of differentiation of the osteoblast phenotype with subsequent mineralization (Gerstenfeld, L. C., S. Chipman, J. Glowacki, and J. B. Lian. 1987. Dev. Biol. 122:49-60) has been examined for the regulation of collagen synthesis, ultrastructural organization of collagen fibrils, and extracellular matrix mineralization. Collagen gene expression, protein synthesis, processing, and accumulation were studied in this system over a 30-d period. Steady state mRNA levels for pro alpha 1(I) and pro alpha 2 collagen and total collagen synthesis increased 1.2- and 1.8-fold, respectively, between days 3 and 12. Thereafter, total collagen synthesis decreased 10-fold while mRNA levels decreased 2.5-fold. In contrast to the decreasing protein synthesis after day 12, total accumulated collagen in the cell layers increased sixfold from day 12 to 30. Examination of the kinetics of procollagen processing demonstrated that there was a sixfold increase in the rate of procollagen conversion to alpha chains from days 3 to 30 and the newly synthesized collagen was more efficiently incorporated into the extracellular matrix at later culture times. The macrostructural assembly of collagen and its relationship to culture mineralization were also examined. High voltage electron microscopy demonstrated that culture cell layers were three to four cells thick. Each cell layer was associated with a layer of well developed collagen fibrils orthogonally arranged with respect to adjacent layers. Fibrils had distinct 64-70-nm periodicity typical of type I collagen. Electron opaque areas found principally associated with the deepest layers of the fibrils consisted of calcium and phosphorus determined by electron probe microanalysis and were identified by electron diffraction as a very poorly crystalline hydroxyapatite mineral phase. These data demonstrate for the first time that cultured osteoblasts are capable of assembling their collagen fibrils into a bone-specific macrostructure which mineralizes in a manner similar to that characterized in vivo. Further, this matrix maturation may influence the processing kinetics of the collagen molecule.

Animals↗
PubMed1982

A study of ultrastructural alterations in experimental non-A, non-B hepatitis by electron-beam analysis.

An electron-beam X-ray microanalysis was carried out on sections of liver biopsy specimens obtained from chimpanzees infected with non-A, non-B hepatitis. The microanalysis was concentrated over areas where typical derangement of the endoplasmic reticulum, with the formation of tubular forms possessing walls with electron-dense central membrane, was visualized. These tubular structures are regarded as the most notable pathological alteration in affected hepatocytes. However, the electron-probe microanalysis showed no deviation of the energy spectrum when compared with the background or control analysis.

Animals↗
PubMed1976

Calcification of alpha-elastin coacervates: a bulk property of elastin.

Scanning electron microscopy and electron probe microanalysis studies are reported on thin sections of calcified coacervates of alpha-elastin. It is found that the capacity of elastin coacervates to initiate calcification is a bulk property of the coacervate and not limited to the serum-coacervate interface, that the calcium phosphate deposits act to bind the protein units together and slow the dissolution and spreading of the coacervate as it floats on an airwater interface, and that, within the limits of detectability, there is no involvement of sulfur. As the charged groups of alpha-elastin had been blocked, the initiation of deposition is due to neutral sites in the protein which are tightly bound to the calcium phosphate deposits.

Animals↗
PubMed1990

Scanning and transmission electron microscopy, and electron probe analysis of the interface between implants and host bone. Osseo-coalescence versus osseo-integration.

Bioinert materials (e.g., alumina implants) and bioactive ceramics (e.g., calcium phosphate ceramics, glass-ceramics) are now extensively used in dentistry. However, the physico-chemical interactions at the interfaces between the implant and the host bone are poorly understood. The purpose of this study was to define the interactions at these interfaces using a combination of analytical techniques: light microscopy, scanning and transmission electron microscopy, electron probe microanalysis, X-ray microradiography, X-ray diffraction, and infrared spectroscopy. Bioinert (pure titanium) and bioactive materials (hydroxyapatite, beta-tricalcium phosphate and biphasic calcium phosphate) were implanted in dogs, and the implants, recovered after various periods of implantation, were analyzed. The results demonstrated the following: the bioactive materials interact with the biological fluid and the living tissues in a specific manner. This process includes biodissolution/biodegradation, apatite crystal precipitation, and bone formation on the implant surface at the expense of the material. The results are discussed according to the limitations of the analytical techniques used. The medical and chemical word coalescence is suggested to describe the specific interactions of bioactive materials and interaction for the phenomenon of physical contact of the bioinert materials with the host bone.

Animals↗