Electron probe analysis of cationic species in pyroantimonate precipitates in epon-embedded tissue.
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Animals↗
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A novel UDP-sugar, UDP-3-ketoglucosamine or UDP-4-ketoglucosamine, from bovine heart muscle reduces metmyoglobin with NAD(P)H.
3-Ketoglucose and similar ketosugars have been identified in microorganisms only and little is known about their functions. UDP-sugars are widely found as an intermediate in sugar metabolism in living organisms. Yet what role UDP-sugars play, or whether they play a direct role in metabolism, is still unknown. UDP-sugars were isolated and purified from bovine heart muscle, and a UDP-sugar fraction capable of NAD(P)H-dependent catalytic reduction of metmyoglobin was detected. Subsequent identification revealed that the active UDP-sugar was UDP-3- or UDP-4-ketoglucosamine. These compounds were purified from bovine cardiac muscle by ultrafiltration, anion-exchange column chromatography and reverse-phase chromatography. They were further characterized by determination of their chemical reducing activity, by comparison with synthetic UDP-3- or UDP-4-ketoglucosamine standards using high-performance liquid chromatography, by estimation of molecular mass using fast atom bombardment mass spectrometry, and by Fourier transform infrared microspectroscopy and electron probe microanalysis. The results suggest that UDP-3- or UDP-4-ketoglucosamine reduces metmyoglobin in bovine cardiac muscle. It is important that the reducing activity displayed by this ketosugar is not the effect of UDP-3- or UDP-4-ketoglucosamine alone but depends on NAD(P)H. In other words, this action of UDP-3- or UDP-4-ketoglucosamine is catalytic.
Animals↗
Two-dimensional imaging of atomic distribution morphology created by holographically induced mass transfer of monomer molecules and nanoparticles in a silica-nanoparticle-dispersed photopolymer film.
We report an electron-probe microanalysis of a hologram recorded in a silica-nanoparticle-dispersed photopolymer film. We used S and Si atoms as label elements to identify formed polymer and nanoparticle species, respectively. It is found that the periodic density distributions of S and Si atoms are out of phase with each other, indicating that those of the formed polymer and nanoparticles are out of phase each other. This result shows decisive evidence of the mutual diffusion of monomer molecules and silica nanoparticles in the film under holographic two-beam interference exposure.
Journal Article↗
Elemental composition of rabbit antral fluid during preovulatory follicular swelling.
Electron probe microanalysis was used to determine the concentrations of Na, Cl, K Ca, Mg, S and P in samples of follicular fluid, ovarian vein serum and peripheral venous serum obtained from virgin rabbits at 2-h intervals up to 10 h after injection of hCG. Throughout this 10-h period the elemental composition of follicular fluid was essentially the same as that of blood serum. However, there was a significant drop in follicular fluid Ca relative to blood during the 10-h period which may reflect Ca involvement in the regulation of oocyte maturation. Significant differences were also found between follicles within rabbits for K and P concentrations.
Animals↗
Dried solidified blood calculi in the urinary tract of cats.
We have noted an increased number of calculi submitted to the Gerald V. Ling Urinary Stone Analysis Laboratory, University of California, Davis, that do not contain crystalline material but appear to be composed of dried solidified blood (DSB). Canine and feline laboratory records from 1986-2003 were reviewed for samples composed of >99% DSB. No calculi from dogs were found, but specimens from 49 cats were composed of >99% DSB, of which almost half (n = 22) had been submitted after 2001. The DSB calculi had been removed surgically or by postmortem examination from all areas of the upper and lower urinary tract. All samples were well formed and could be divided in half with Rongeur forceps. Detailed case information was available for 12 cats. Urinalyses were available for 9 of the 12 cats, and the mean specific gravity was 1.017 (range, 1.009-1.032). Red blood cells were reported in the sediment of all cats, with most containing >100 RBC/hpf. Ureteral obstructions but no radio-opaque calculi were visible by radiography, including radiographic contrast studies. Reports of ultrasound examinations were available for 10 cats, and discrete calculi were not recorded. In addition to polarized light microscopy, infrared spectroscopy and electron probe microanalysis were performed on a subset (n = 6, DSB calculi; n = 3, control calculi) of samples. Significantly more carbon, nitrogen, and sulfur (P = .012, P = .02, and P = .012, respectively) were present in the elemental analysis of the DSB calculi than in the control calculi, suggesting that the DSB calculi are primarily formed from organic material. At this time, we are uncertain why these DSB calculi become solidified, and we recommend that samples be submitted both in formalin and preservative free to further investigate their etiology.
Animals↗
[Study of histostructure of fused human enamel by laser irradiation].
By applying the heat effect of laser, it was attempted to fuse artificial materials to tooth enamel with laser irradiation for direct bonding tooth restoration. At first the fusing methods of enamel were studied, and then the fused enamel was analized by polarized microscope, contact microradiogram, vickers hardness, electron probe microanalysis and X-ray diffraction. Furthermore the methods of fusing artificial materials to tooth enamel. Through these studies, the following results were obtained. 1. Among the pigments that were placed on the enamel surface, Fe2O3- particulate- dispersed agents solution was most suitable for the fusion of enamel, and the best irradiation condition was the focused beam of 20 J energy (20 W X 1.0 sec.). 2. Fused enamel, which is proved to be composed of not only hydroxyapatite but also alpha-tricalcium phosphate, is more radiopaoue than non-fused enamel and the birefringence is dissimilar also, but the hardness is the same. 3. It was possible to fuse artificial alpha-tricalcium phosphate to fused enamel, and the results of the analysis were the same as those mentioned before.
Calcium Phosphates↗
The effects of cyproterone acetate on the elements in the intraluminal fluids of the testis and epididymis of the rat.
Spermatozoal maturation and the integrity of the epididymis are dependent on the action of androgen. Micropuncture techniques and electron probe microanalysis were used to investigate the effect of cyproterone acetate on the concentrations of seven elements in intraluminal fluids of the testis, rete testis, and epididymis. After 4 weeks of treatment with cyproterone acetate, the sodium concentration rose in the corpus epididymidis (74.4 +/- 5.4 to 102 +/- 6 mmol/L, p less than 0.01). The concentration of potassium rose in seminiferous tubular fluid (33.9 +/- 2.7 to 49.4 +/- 4.4 mmol/L, p less than 0.01) and caput epididymidal fluid (15.9 +/- 1.4 to 25.7 +/- 0.9 mmol/L, p less than 0.01) after 8 weeks of cyproterone acetate treatment. The chloride concentration rose in the caput (23.7 +/- 0.8 to 65.4 +/- 12.5 mmol/L, p less than 0.01) and distal cauda (39.4 +/- 4.6 to 74.7 +/- 10.8 mmol/L, p less than 0.01) epididymidis after 8 weeks of treatment. Cyproterone acetate had no effect on the concentrations of phosphorus, calcium, and magnesium. The sulfur concentration rose in seminiferous tubular fluid (4.3 +/- 0.3 to 7.3 +/- 0.3 mmol/L, p less than 0.01) and distal cauda fluid (5.3 +/- 0.5 to 14.0 +/- 1.6 mmol/L, p less than 0.01) after 8 weeks of treatment with cyproterone acetate. Four weeks of treatment also increased the sulfur concentration in the distal cauda (6.8 +/- 1.6 to 13.4 +/- 1.5 mmol/L, p less than 0.01). Cyproterone acetate treatment did not affect the concentration of any element in rete testis fluid or serum.
Animals↗
[The effect of tetracycline antibiotics on the calcium and magnesium content of rat incisors].
Using electron probe microanalysis, the authors determined the calcium and magnesium contents in the incisors of rats treated with different doses of tetracycline and oxytetracycline, and in those of untreated rats. The contents of these elements were significantly lower in the dentine of the treated animals than in that of the control animals, whereas the enamel samples showed no statistically significant differences. The concentration tendency in different tooth sections, from the periphery to the pulp canal, i.e., decrease in calcium and increase in magnesium, was not influenced.
Animals↗
Initial studies with high resolution TEM and electron energy loss spectroscopy studies of ferritin cores extracted from brains of patients with progressive supranuclear palsy and Alzheimer disease.
Studies of crystallographic structure and composition of core nanocrystals of ferritin bound to aberrant tau filaments extracted from progressive supranuclear Palsy (PSP) and Alzheimer disease (AD) brain tissues were performed using high resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS). The results were compared with those obtained from synthetic Fe3O4 crystal (magnetite) and horse spleen ferritin cores. Core dimensions of ferritin molecules from PSP and AD were similar to those found in normal brain. Ferritin cores nanocrystals in AD seems to have less ordered structure than in PSP. Some nanocrystals did not have the hexagonal ferrihydrite structure generally found in healthy ferritin but rather a cubic structure similar to magnetite, a crystalline form in which both Fe2+ and Fe3+ are present. The presence of ferrous ion, Fe2+, may indicate some dysfunction in these pathological ferritins that might contribute to production of free radicals via the Fenton reaction involved in neurodegeneration.
Alzheimer Disease↗
[Spin-dependent electronic structure near the iron atom in rubredoxin].
The fine structure of X-ray absorption spectrum of Fe in rubredoxin was interpreted on the basis of the multiple scattering theory and the results of calculations of the self-consistent potential. For biological molecules, such calculations were made for the first time. It was found that the Fe-S interaction is the main factor, which determines the electronic structure of the protein active center. The changes in spectrum shape are mostly due to the spin configuration of 3d-electrons. It was shown that the dipole transition element significantly changes near the absorption edge; therefore, it is impossible to determine the distribution of unoccupied electronic p-states directly from experiment. However, the results of calculations obtained in this work are consistent with the corresponding experimental data, indicating the adequacy of the calculated densities of free electronic states.
Electron Probe Microanalysis↗
Focused ion beam in dental research.
Focused ion beam (FIB) has been available for over 10 yrs but until recently its usage has been confined to the semiconductor industry. It has been developed as an important tool in defect analysis, circuit modification and recently transmission electron microscope sample preparation. This paper introduces FIB and demonstrates its application in dental research. Its ion and electron imaging modes complement the SEM while its ability to prepare TEM samples from a wide range of material will allow the study of new types of adhesive interface. As an example, its use is described in the characterization of the interface of resin to a tribochemically treated surface of an experimental fiber-reinforced resin-based composite. As with all new techniques, the initial learning curve was difficult to manage. This new instrument offers opportunities to expand research in dental materials to areas not possible before.
Aluminum Oxide↗
Microstructures of brazings and welds using grade 2 commercially pure titanium.
PURPOSE: Microstructural analyses of commercially pure titanium (CpTi) are scarce. The present report presents the micrographs, fractographs, elemental characteristics, and hardness profiles of brazed joints and weldments using machined rods of CpTi. MATERIALS AND METHODS: CpTi rods were joined using four techniques: laser welding, electric-arc welding, electron-beam welding, and gold- and Ti-filler brazing. The specimens were then subjected to tensile and fatigue loading. After sectioning and patterning, optical micrographs of intact joints were obtained. Fractured surfaces were investigated using scanning electron microscopy (SEM). The joint's composition was determined by SEM-energy dispersive x-ray analysis. Hardness was determined at specific locations using a microindenter. RESULTS: While laser welding left the parent metal's equiaxed structure fairly intact, electric-arc welding, electron-beam welding, and brazing created a heat-affected zone in the vicinity of the joint. The extent and characteristics of the heat-affected zone depended on the amount of heat transferred to the specimens. In this respect, brazing essentially increased grain size and altered their shape. Electron-beam welding augmented this phenomenon, yielding grains that encompassed the full diameter of the joint. Electric-arc welding disrupted the granular pattern and generated highly lamellar/acicular structures. CONCLUSION: Hardness was not a good indicator of mechanical resistance, nor was the joint's structural continuity with the parent substrate. Still, acicular microstructures were characterized by a peculiar behavior in that such joints were highly resistant to tensile stresses while their fatigue strength ranged among the lowest of the joints tested.
Copper↗
[Study on trace elements in epithelial cells during oral carcinogenesis prevented by garlic].
Sixty-two Wistar rats were divided randomly into two groups, thirty-one for each group. The posterior hard palatal mucosae of all animals were painted thrice weekly with 0.5% 4-nitroquinoline 1-oxide(dissolved in dimethyl sulfoxide). Before that, the garlic injection solution and the distilled water were painted at the same place of the experimental and control group animals, respectively. All animals were killed in turn from the beginning of the experiment at random at the 10th, 13th, and 19th week. Then, trace elements of intranuclear and cytoplasm of epithelial cells or cancer cells at the mentioned weeks were surveyed by electron probe microanalysis. The results were that garlic decreased the levels of intranuclear and cytoplasm copper(P < 0.05); the levels of intranuclear and cytoplasm selenium at the 10th week and the 13th week(P < 0.05) and those of zinc at the 19th week (P < 0.01) increased. So, garlic inhibits oral carcinogenesis by changing concentrations of intranuclear and cytoplasm trace elements that is copper, zinc, selenium, and the ratio of the three elements.
4-Nitroquinoline-1-oxide↗
Platinum-diaminobenzidine reaction and its contribution to the quantitation of cytochrome oxidase activity.
The platinum-diaminobenzidine (Pt-DAB) reaction, which yields a black, electron-dense, insoluble, Pt-containing reaction product at the active site of cytochrome oxidase without postosmification, has been developed. This reaction permits us to quantitate the oxidase activity in an individual mitochondrion or in its constitutent part by the energy dispersive X-ray analysis (EDAX), based on the platinum atoms incorporated in the product.
3,3'-Diaminobenzidine↗
[Study on the interface of Ti-porcelain fused under different surface treatment].
OBJECTIVE: This study was made to observe the topography and ionic diffusion of the elements titanium, silicon, et cetera in the Ti-porcelain interface area which was pretreated with different methods. METHODS: Ti-bond porcelain was fused on commercial pure titanium (CPT) with 8 different pretreatment methods; according to the temperature of the preoxidation, there were 300 degrees C, 400 degrees C, 500 degrees C and 600 degrees C groups, and based on the oxidizing-time in the air, there were 5 min, 15 min, 2 h and 24 h groups. The topography and ionic diffusion of elements in the Ti-porcelain interface area were observed with scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) respectively. RESULTS: There were clefts and exfoliations in the 500 degrees C pre-oxidation group and 600 degrees C pre-oxidation group in SEM images. The distribution of titanium in the interlayer in EPMA images decreased from the titanium surface to porcelain, which was opposite to the distribution of silicon. CONCLUSION: The clefts and exfoliations suggested the position of the fracture and brittleness of alpha-Ti[o] layer. The widths of ionic diffusion in the eight groups were different, but it was difficult to measure and compare them exactly.
Dental Alloys↗
Inorganic components and the fine structures of marginal and deep subgingival calculus attached to human teeth.
Inorganic components and the fine structures of marginal ledge-type and deep subgingival spiny deposits in human old dental calculus were investigated by scanning electron microscopy and energy dispersive electron-probe microanalysis. The ledge-type deposits consisted of the extra- and intracellular calcifying deposits, large plate-shaped crystals, and bacillus-shaped deposits composed of hexahedrally based crystals. The spiny deposits were mainly formed by aggregations of the bacillus-shaped deposits. In the outer and middle layers of the spiny deposits, the Ca, P, and Mg concentrations were all significantly higher than those of the ledge-type deposits. A consideration of the crystal shapes and Ca, P, and Mg molar ratios reveals the following differences. Calculus components of the ledge-type deposits contained crystal types quite similar to sandy grain-shaped hydroxyapatite (HAP), plate-shaped octacalcium phosphate (OCP), and hexahedral Mg-containing whitlockite (WHT). On the other hand, in the spiny deposits, the Mg-containing WHT type comprised a large proportion of the calculus; the HAP type was found in the outermost and inner layers; and no OCP type was detected.
Calcium Phosphates↗
Ultrastructural localization of calcium in normal and abnormal skeletal muscle.
Calcium was demonstrated ultrastructurally as a fine black reaction product with unbuffered 2% saturated potassium pyroantimonate, pH 9.4. In comparison with normal muscle, there was increased precipitate in degenerating skeletal muscle fibers and some degenerating-regenerating fibers occurring in pathologic human muscle, regardless of disease entity, and in experimentally injured rat muscle. The pathologically increased calcium was mainly within the sarcoplasmic reticulum and mitochondria. Both structures could be completely blackened. Nuclear calcium was also increased, the precipitates being localized as circular profiles within the nucleoli and heterochromatin as well as being associated with the nuclear envelope. Myofibrillar calcium was only modestly increased. When normal rat muscle was preincubated in 136 mM calcium-enhanced Hanks' medium, calcium accumulated in the muscle fibers--it was especially heavy in the mitochondria and sarcoplasmic reticulum and appeared identical with the pathologic human and rat muscle fibers. Preincubation of normal rat muscle in 0.1 M acetate buffer (pH 4.65) before calcium loading augmented myofibrillar staining, mainly in the H-zone of the A-bands excluding the M-zone and in broad irregular N1, N2, and "N3" lines of the I-bands. EMMA-4 electron probe microanalysis and EGTA (ethylene glycolbis (beta-aminoethyl ether)N,N'-tetraacetic acid) chelation prior to staining confirmed that the precipitate in the several loci was calcium antimonate. It is proposed that in skeletal muscle fibers injured by various pathologic processes, a breach of the plasmalemma barrier to calcium occurs as a very early abnormality. Extracellular calcium would then pour into the aqueous sarcoplasm of the muscle fiber, from which it would be withdrawn by and accumulated with the still active organelles normally having a great avidity for uptake of this ion, especially the mitochondria and sarcoplasmic reticulum. The resultant organellar calcification would impair function and damage the structure of proteins and phospholipids.
Animals↗
[Cytoplasmic K/Na balance in heart muscle cells of young and old rats under oxygen and substrate deficiency].
Age-related changes in the content of the major cellular cations of potassium and sodium in heart muscle cells of Wistar rats have been studied. The cytoplasmic concentration of potassium and sodium was determined by the electron probe microanalysis. The results revealed differences in both the concentration of the elements in young and old control animals and the responses of a cardiomyocyte to the state of acute hypoxic deenergization modelled on a perfused heart. The data are consistent with the hypothesis about the presence of genetically-related age changes in the conductance of potassium channels, which in old animals are realized against the background of deficient supply of tissues with oxygen and substrate.
Aging↗