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PubMed1996

Effects of m-nisoldipine on aortic calcium accumulation in rats with vascular calcium overload.

AIM: To study the effects of a novel calcium channel blocker, m-nisoldipine, on vascular calcium overload (VCO) at both tissue and cellular levels. METHODS: VCO was induced in Wistar rats by treatment with colecalciferol (Col, 400,000 IU.kg-1, p.o.) and an aqueous mixture of ethanol and polyethyleneglycol-400 for 3 d. The tissue and subcellular calcium contents of aorta were determined by atomic absorption spectrometer and electron probe microanalysis, respectively. RESULTS: Chronic treatment with m-nisoldipine (m-Nis, 1-15 mg.kg-1, p.o., bid) only had mild inhibition on the elevation of total calcium in aorta, and the dose-response relationship of m-Nis displayed a bell shape, with inhibition ratio of 24% only for m-Nis 2.5 mg.kg-1. The effect of verapamil (12.5 mg.kg-1, p.o., bid) was a little better than that of m-Nis. The intracellular VCO in medial smooth muscle cells of aorta were remarkably inhibited by m-Nis (2.5 mg.kg-1), with inhibition ratios of 72% for cytoplasm and 76% for mitochondrion. The calcium accumulation in nucleus was reduced to a lesser degree than those in cytoplasm and mitochondrion. CONCLUSION: As for aorta in VCO rats, m-Nis mainly had conspicuous inhibition on intracellular VCO in medial smooth muscle cells, particularly in cytoplasm and mitochondrion, but with little effect on extracellular calcium deposition at tissue level.

Animals↗
PubMed1989

Electron-probe X-ray microanalysis of sodium ion content in vascular smooth muscle cells from spontaneously hypertensive and normotensive rats.

In aortic smooth muscle cells from 12 spontaneously hypertensive rats (SHR) of the Münster strain and 11 normotensive Wistar-Kyoto rats (WKY), the intracellular Na+ content was measured by electron-probe microanalysis. Measurements were performed in aortic cryosections 3 microns thick; the Na+ content was 12.5 +/- 2.4 g/kg dry weight in SHR versus 6.96 +/- 1.1 g/kg dry weight in WKY (P less than 0.01). Thus, aortic smooth muscle cells from SHR are characterized by a markedly elevated intracellular Na+ content compared with normotensive cells. This may either be due to genetically determined disturbances in transmembrane Na+ transport or to a circulating factor affecting Na+ transport. Cellular Na+ handling may be disturbed in SHR aortic smooth muscle as it is in hypertensive blood cells.

Animals↗
PubMed1986

A sample preparation for quantitative determination of magnesium in individual lymphocytes by electron probe X-ray microanalysis.

We present a sample preparation method for measuring magnesium in individual whole lymphocytes by electron probe X-ray microanalysis. We use Burkitt's lymphoma cells in culture as the test sample and compare X-ray microanalysis of individual cells with atomic absorption analysis of pooled cell populations. We determine the magnesium peak-to-local continuum X-ray intensity ratio by electron probe X-ray microanalysis and calculate a mean cell magnesium concentration of 39 +/- 19 mmol/kg dry weight from analysis of 100 cells. We determine a mean cell magnesium concentration of 34 +/- 4 mmol/kg dry weight by atomic absorption analysis of pooled cells in three cell cultures. The mean cell magnesium concentrations determined by the two methods are not significantly different. We find a 10% coefficient of variation for both methods of analysis and a 30% coefficient of variation in magnesium concentration among individual cells by electron probe X-ray microanalysis. We wash cells in ammonium nitrate for microanalysis or in buffered saline glucose for atomic absorption analysis. We find cells washed in either solution have the same cell viability (85%), recovery (75%), cell volume (555 microns 3) and cytology. We air dry cells on thin film supports and show by magnesium X-ray mapping that magnesium is within the cells. We conclude that: our microanalysis cell preparation method preserves whole intact lymphocytes; there is no systematic difference in results from the two methods of analysis; electron probe X-ray microanalysis can determine the variation in magnesium concentration among individual cells.

Burkitt Lymphoma↗
PubMed1984

Distribution of elements in the pancreatic exocrine cells determined by electron probe X-ray microanalysis.

We measured the intracellular electrolytes of acinar cells by making electron probe X-ray microanalysis of hydrated and dehydrated sections of freshly frozen dog pancreas. The concentrations of electrolytes in the cytoplasm were: Na 4.8 +/- 2.1, K 132 +/- 15, Cl 14 +/- 4.7, P 165 +/- 36, S 19 +/- 2.8 and in zymogen granules: Na 6 +/- 5, K 60 +/- 16, Cl 31 +/- 20, P 36 +/- 8, S 172 +/- 25, Ca 7 +/- 5 (mean +/- S.D. mmol/kg wet weight). The cytoplasm, which is rich in rough endoplasmic reticulum, had low Na and high K concentrations, as compared with levels in the acinar cells of other exocrine glands such as the submandibular gland, the bulk of which is occupied by secretory granules. Though the representative feature of secretory granules was a high S content, occasionally low S peaks of spectra from secretory granules were obtained. These findings may reflect the content of mature zymogen granules and immature condensing vacuoles. Pilocarpine stimulation increased cytoplasmic Na, Cl and Ca and decreased K levels in the pancreatic acinar cells. This indicates that secretory stimulation increases the permeability of the cell membrane to Na, Cl and K ions and that there is a simultaneous Ca release from the intracellular Ca stores such as zymogen granules and endoplasmic reticulum, and/or Ca influx from the extracellular space.

Animals↗
PubMed1990

Disruption of cellular elements and water in neurotoxicity: studies using electron probe X-ray microanalysis.

Regulation of elements and water in nerve cells is a complex, multifaceted process which appears to be vulnerable to neurotoxic events. However, much of our knowledge concerning the potential role of elements in nerve cell injury is limited by the relatively gross level of corresponding analyses. If we are to confirm and understand the proposed role, more precise and detailed information is needed. As indicated in this commentary, research employing electron probe microanalysis and digital X-ray imaging has begun to provide this necessary information. Recent EPMA studies of nerve and glial cells in the peripheral and central nervous systems have shown that each cell type and their corresponding morphologic compartments exhibit unique distributions of elements and water. The use of microprobe analysis has allowed us to document precisely how elements and water redistribute in morphological compartments of damaged nerve cells. Accumulating evidence from EPMA studies suggests that, rather than being an epiphenomenon, intracellular changes in diffusible elements might mediate the functional and structural consequences of neurotoxic insult. It is also evident from this research that elements other than Ca might play a pertinent role in the injury response and that changes in intraneuronal elemental composition might develop according to a specific temporal pattern, e.g., transection-induced sequential alterations in axonal K, Na, Cl, and Ca. Therefore, rather than conducting end-point studies, longitudinal investigations are necessary to define the sequential pattern of elemental perturbation associated with a given neurotoxic event. Such research can also help identify the role of individual elements in the injury response. Future microprobe studies should be combined with measurements of ion levels (e.g., using fura-2 or ion selective electrodes) to provide a comprehensive and dynamic view of elemental deregulation. In addition, parallel biochemical studies should be performed to determine mechanisms of elemental disruption and possible biochemical and metabolic consequences of this disruption. Although evidence presented in this commentary suggests that each type of neurotoxic event produces a characteristic pattern of decompartmentalization, further work is necessary to confirm this possibility. Finally, based on a presumed involvement of elements in nerve injury, efforts are currently underway in several laboratories to develop appropriate pharmacological therapies for certain chemical- and trauma-induced neuropathological conditions (Dretchen et al., 1986; El-Fawal et al., 1989; Beattie et al., 1989).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1988

A scanning electron microscopy and electron probe X-ray microanalysis (SEM-EPMA) of pink teeth.

Samples of postmortem pink teeth were investigated by scanning electron microscopy and electron probe X-ray microanalysis. Fracture surfaces of the dentin in pink teeth were noticeably rough and revealed many more smaller dentinal tubules than those of the control white teeth. Electron probe X-ray microanalysis showed that the pink teeth contained iron which seemed to be derived from blood hemoglobin. The present study confirms that under the same circumstance red coloration of teeth may occur more easily in the teeth in which the dentin is less compact and contains more dentinal tubules.

Animals↗
PubMedDate not supplied

Electron probe X-ray microanalysis of otoconia in the guinea pig inner ear.

By using the electron probe X-ray microanalysis technique, the elemental composition of otoconia was analyzed in the normal adult pigmented guinea pig. In the X-ray spectra of otoconia, the most abundant element was Ca, but significant peaks for P, S, Cl and K were also detected. The comparison of the elemental composition in the utricular and saccular otoconia did not show any significant difference. Regression analysis revealed that the concentrations of Ca and K are related by a linear function in both the utricular and saccular otoconia. Analysis of otoconia of different sizes showed that there were no differences in Ca concentration in small, normal and large otoconia. The comparison of other elemental compositions revealed that P, S, Cl and K in the central part of saccular small otoconia showed higher concentrations than those of normal or large otoconia. P, S, Cl and K in the utricular small otoconia showed relatively higher concentrations. These findings may indicate that the small otoconia are immature or newly generated.

Animals↗
PubMed2005

Single-particle characterization of four "Asian Dust" samples collected in Korea, using low-Z particle electron probe X-ray microanalysis.

A single-particle analytical technique, named low-Z particle electron probe X-ray microanalysis (low-Z particle EPMA), employing an ultrathin window X-ray detector and enabling the quantitative determination of even low-Z elements such as C, N, and O, is applied to characterize "Asian Dust" samples, collected in ChunCheon, Korea, during four Asian Dust storm events on March 7, 2000, April 7, 2000, March 22, 2001, and May 17, 2001. In this study, it is demonstrated that single-particle analysis using the low-Z particle EPMA provides detailed information on various types of chemical species in the samples. The most abundantly encountered particles, both in coarse and fine fractions, are aluminosilicates. The relative abundances of those particles on the basis of their size are different between the four Asian Dust samples. The sample collected on March 7, 2000 did not experience any chemical modification during its transport because the sample does not contain particles of chemical species that result from atmospheric reactions. The sample collected on April 7, 2000 contains both genuine and reacted sea-salt particles. The genuine sea-salts are in the form of a mixture of NaCl and MgCl2 entrained during their passage over the Yellow Sea. The reacted sea-salts particles are encountered very much in fine fraction. The sample collected on March 22, 2001 shows somewhat significant chemical modification both for CaCO3 and sea-salts particles. For this sample, a significant number of reacted CaCO3 and sea-salt particles, such as those containing nitrate and/or sulfate, are encountered, implying that CaCO3 and sea-salts particles have reacted with sulfur or nitrogen oxide species during their long-range transport. The sample collected on May 17, 2001 experienced the most extensive chemical modification during its transport. In addition to the observation of the extensively reacted CaCO3 and sea-salt particles, reacted K2CO3 particles are also extensively encountered in this sample, which implies that K2CO3 species should be regarded as an additional important chemical species in the study of the chemical modification of Asian Dust particles during long-range transport.

Air Movements↗
PubMed1987

Electron probe X-ray microanalysis of bacterial DNA.

X-ray microanalysis provides a potentially useful technique for the detection, quantitation and statistical analysis of cation levels in microsamples of freshly-isolated bacterial DNA. The dilution of the sample deposited on the electron microscope grid is important both for the visualisation of discrete macromolecules and also for the microanalytical detection of a full range of divalent cations. Approximately 50 detectable cations (30 monovalent, 20 divalent) were present per 100 phosphorus atoms, which is equivalent to one detectable cation per 2 nucleotides. Significant correlations in the occurrence of K, Ca, Ni and Zn with continuum and also with phosphorus suggests that these cations are distributed homogeneously in the sample, while Mn, Fe and Cu showed no such correlations. The occurrence of K in the different spectral analyses did not show any significant correlation with any divalent cations, whereas significant correlations did occur between divalent cations. This suggest that fundamental differences occur between monovalent and divalent cations in their association with the DNA molecule.

Calcium↗
PubMed2002

Single-particle characterization of urban aerosol particles collected in three Korean cites using low-Z electron probe X-ray microanalysis.

A recently developed single-particle analytical technique, called low-Z electron probe X-ray microanalysis (low-Z EPMA), was applied to characterize urban aerosol particles collected in three cities of Korea (Seoul, CheongJu, and ChunCheon) on single days in the winter of 1999. In this study, it is clearly demonstrated that the low-Z EPMA technique can provide detailed and quantitative information on the chemical composition of particles in the urban atmosphere. The collected aerosol particles were analyzed and classified on the basis of their chemical species. Various types of particles were identified, such as soil-derived, carbonaceous, marine-originated, and anthropogenic particles. In the sample collected in Seoul, carbonaceous, aluminosilicates, silicon dioxide, and calcium carbonate aerosol particles were abundantly encountered. In the CheongJu and ChunCheon samples, carbonaceous, aluminosilicates, reacted sea salts, and ammonium sulfate aerosol particles were often seen. However, in the CheongJu sample, ammonium sulfate particles were the most abundant in the fine fraction. Also, calcium sulfate and nitrate particles were significantly observed. In the ChunCheon sample, organic particles were the most abundant in the fine fraction. Also, sodium nitrate particles were seen at high levels. The ChunCheon sample seemed to be strongly influenced by sea-salt aerosols originating from the Yellow Sea, which is located about 115 km away from the city.

Aerosols↗
PubMed2001

Single-particle analysis of aerosols at Cheju Island, Korea, using low-Z electron probe X-ray microanalysis: a direct proof of nitrate formation from sea salts.

A recently developed electron probe X-ray microanalysis (EPMA), called low-Z EPMA, employing an ultrathin window energy-dispersive X-ray detector, was applied to characterize aerosol particles collected at two sampling sites, namely, Kosan and 1100 Hill of Cheju Island, Korea, on a summer day in 1999. Since low-Z EPMA can provide quantitative information on the chemical composition of aerosol particles, the collected aerosol particles were classified and analyzed based on their chemical species. Many different particle types were identified, such as marine-originated, carbonaceous, soil-derived, and anthropogenic particles. Marine-originated particles, such as NaNO3- and Na2SO4-containing particles, are very frequently encountered in the two samples. In this study, it was directly proven that the observed nitrate particles were from sea salts. In addition, two types of nitrate particles from sea salts were observed, with and without Mg. The sodium nitrate particles without Mg were believed to be collected as crystalline form, either with the sodium nitrate particles being fractionally recrystallized within evaporating seawater drops or with recrystallized sodium chloride particles having reacted with gaseous nitrogen species in the air to form the crystalline sodium nitrate particles. The other seemed to be collected as seawater drops, where the atmospheric reaction had occurred in the droplets, and thus sodium as well as magnesium nitrates were observed. Carbonaceous particles are the most abundant in the samples at both sites. From this study, it was found that about three-quarters of the carbonaceous particles in the samples were biogenic, which partially explains a previously reported observation of a large concentration of organic carbon particles as compared to elemental carbon. Various soil-derived particles were also observed. In addition to aluminosilicate- and iron oxide-containing particles, which are ubiquitous components in soil-derived particles, CaCO3-, Al2O3- and Cr-containing particles were also frequently encountered.

Aerosols↗
PubMed1983

Crystalloids in salivary duct cysts of the human parotid gland. Scanning electron microscopical study with electron probe X-ray microanalysis.

Crystalloids found in salivary duct cysts of the human parotid gland were examined by scanning electron microscopical observations with electron probe X-ray microanalysis. The cystic spaces were filled with numerous crystalloids which had a variety of forms with slight eosinophilic and glassy appearance. Scanning electron microscopically, crystalloids were hexagonal and rhombohedral in shape, and cutting the surface showed a polycyclic structure or regular parallel lamination. By electron probe X-ray microanalysis, sulphur was the only detected element. The present study suggests that crystalloids resulted from deposition from supersaturated saliva containing sulphur containing compounds into the cystic lumen or into epithelial cytoplasm.

Crystalloid Solutions↗
PubMed1985

Quantitative electron probe x-ray microanalysis and densitometric mass determination of individual rat blood platelets.

An improved method for quantitative electron probe X-ray microanalysis of thin biological specimens, introduced recently, has been applied to the elemental analysis of rat blood platelets. The method uses the X-ray signal to quantify the elemental content of an object and electron scattering to determine the total dry mass of the object. Along with the dry mass distribution, data were obtained on the content and mass fraction of calcium, magnesium, and sulfur in 31 individual platelets. The mean platelet dry mass was found to be 985 fg. The mean Ca, Mg, and S contents were 1.80, 3.41, and 18.3 fg, with mean dry mass fractions of 0.195, 0.396, and 1.96%, respectively. Furthermore, these elements appear to be unevenly distributed among the platelet population.

Animals↗
PubMed1994

Calcium-sequestering organelles of Dictyostelium discoideum: changes in element content during early development as measured by electron probe X-ray microanalysis.

Starving Dictyostelium discoideum amoebae aggregate within a few hours by chemotaxis towards the attractant cAMP to form a multicellular organism. The differentiating cells possess rapid and efficient calcium buffering and sequestration systems which enable them to restrict changes in the cytosolic free calcium concentration temporally and spatially during their chemotactic reaction and allow the continuous accumulation of Ca2+ during development. In order to identify and to characterize calcium storage compartments, we analyzed the element content of amoebae at three consecutive stages of differentiation. Determination of the element distribution was done using energy-dispersive X-ray microanalysis of freeze-dried cryosections of rapid-frozen cells. Amoebae were frozen in the vegetative and aggregation-competent state and after formation of aggregates. Aggregation-competent as well as aggregated cells contained mass dense granules with large amounts of calcium together with phosphorous and either potassium or magnesium: in aggregation-competent cells calcium was colocalized with potassium, whereas in aggregated cells the mass dense granules contained calcium and magnesium. Although mass dense granules were also present in undifferentiated, vegetative cells, they contained only low amounts of phosphorous and potassium together with little Ca and Mg. We conclude that during their differentiation D. discoideum cells use an intracellular storage compartment to sequester Ca and other cations constantly throughout development.

Animals↗
PubMed1981

Scanning electron probe x-ray microanalysis of elemental distributions in freeze-dried cryosections of Bacillus coagulans spores.

High-resolution scanning electron probe X-ray microanalysis had been employed to examine elemental distributions in freeze-dried cryosections of Bacillus coagulans spores. Calcium, manganese, and phosphorus were concentrated in the protoplast and the coat. Iron was found in the coat but not in the protoplast, whereas the silicon seen on the coat of other spore species was absent. Sulfur was present in the coat, but was distributed over a broader area than the other elements, which suggested that phosphorus and the metal ions were located in the outer coat layer.

Bacillus↗