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At least 1,711 records · Page 95Linked to original sources
PubMed2000

A new method for detecting and localizing cell markers endocytosed by fibroblasts in epoxy resin semi-thin sections using scanning electron microscopy combined with energy dispersive X-ray microanalysis after ion-etching.

Cell marking is widely used to examine cell development and differentiation in developmental biology. We developed a new method for localizing cell markers in a semi-thin epoxy section with scanning electron microscopy. Cultured fibroblasts ingesting carbon particles were autologously transplanted into a rabbit transparent ear chamber, 6 mm in diameter and 100 microm in depth. Eight days after the transplantation, tissues in the chamber were fixed and embedded in epoxy resin. Semi-thin sections were cut and stained with toluidine blue. Fibroblasts in connective tissues which contained black spots were observed with a light microscope. These sections were subsequently ion-etched with an ion-coater and coated with platinum. The same fibroblasts were then visualized by secondary electron imaging using a scanning electron microscope. A nucleus with nuclear envelope, nuclear pores, a nucleolus and heterochromatin, mitochondria with cristae and rough endoplasmic reticulum were observed in the fibroblasts. The black spots in the fibroblasts were identified as bright bodies with the scanning electron microscope. The bright bodies were found to be a lump of tiny particles less than 100 nm in diameter. In order to analyse such particles with energy dispersive X-ray microanalysis, ion-etched sections were coated with carbon. X-ray energy spectrometry clearly demonstrated that these were carbon particles, which had been endocytosed by the fibroblast. This suggests that scanning electron microscopy combined with energy dispersive X-ray microanalysis is useful for detecting carbon particles in the cytoplasm at an ultrastructural level in semi-thin epoxy sections subsequent to ion etching and that this method may be applicable to other cell markers, such as gold particles to track cells in the field of cell development and cell differentiation.

Animals↗
PubMed1998

Nickel and gold in skin lesions of pierced earlobes with contact dermatitis. A study using scanning electron microscopy and x-ray microanalysis.

Cases of contact dermatitis due to nickel and gold especially in pierced earlobes, are increasing in number the world over. However, the presence of these metal fragments has not been demonstrated in the skin lesions. The aim of this study was to demonstrate nickel and gold in contact dermatitis lesions in pierced earlobes. Skin specimens taken from such earlobe lesions were examined using scanning electron microscopy and x-ray microanalysis. The pierced earrings worn when the lesions appeared were examined by the same techniques, and their analysis confirmed. In nickel dermatitis, small, electron-dense fragments were seen in the specimens examined by scanning electron microscopy, and nickel was detected in locations corresponding to these fragments by x-ray microanalysis. In contact dermatitis due to gold, small dense fragments containing gold were observed. It is suggested that small fragments of nickel and gold remain in the skin lesions of pierced earlobes for a long time, even after the studs have been removed, and cause prolonged irritation and various cutaneous reactions.

Adult↗
PubMed1984

An investigation into the type of union achieved between cast cores and Wiptam wire posts.

The type of union formed between Wiptam wire posts and cast cores has been investigated. Scanning electron microscopy of sectioned 'as cast' specimens showed that the union between Wiptam posts and cast cores was predominantly mechanical in nature. Diffusion studies, however, using an X-ray Microanalysis Unit, revealed that there was evidence of diffusion of silver atoms into the post from the core. This suggests that the bonding between the two components is not merely a simple mechanical lock.

Chemical Phenomena↗
PubMed2001

Design and application of new 16S rRNA-targeted oligonucleotide probes for the Azospirillum-Skermanella-Rhodocista-cluster.

The genera Azospirillum, Skermanella and Rhodocista form a phylogenetic subgroup within the alfa subclass of Proteobacteria. Based on comparative 16S rRNA sequence analysis a nested set of new oligonucleotide probes was designed. It comprises probes for the whole genus cluster Azospirillum-Skermanella-Rhodocista, for the Azospirilli subcluster I including A. lipoferum, A. doebereinerae, A. largimobile, A. brasilense and A. halopraeferens, for the Azospirilli subcluster II including A. amazonense, A. irakense and the genus Skermanella, for the genus Rhodocista as well as for all Azospirilli species or species cluster. The new probes allow a fast and reliable in situ identification of bacteria belonging to the Azospirillum-Skermanella-Rhodocista-cluster at different phylogenetic levels. The specificity of the new probes was tested with 56 strains of the Azospirillum-Rhodocista-Skermanella-cluster and selected reference cells from other genera by hybridising with the complete probe set. In addition, applications of the fluorescently labelled probes for in situ identification of isolates and for the in situ localisation of A. brasilense on maize roots were demonstrated using confocal laser scanning microscopy.

Alphaproteobacteria↗
PubMed2006

Chinch bug (Hemiptera: Blissidae) mouthpart morphology, probing frequencies, and locations on resistant and susceptible germplasm.

Chinch bugs are common pests of many agronomic and horticulturally important crops and turfgrasses. Previous research has indicated that some grasses exhibit resistance to multiple chinch bug species, whereas others are resistant to only one species. The objectives of this research were to document differences in the probing frequencies and locations among Blissus species as well as differences in mouthpart morphology as a first step in understanding the differential responses of grasses to chinch bug feeding. Scanning electron microscopy detected differences in the total lengths of proboscises as well as individual mouthpart segments among the four species studied. Blissus occiduus Barber probed significantly more often on buffalograss, Buchloë dactyloides (Nuttall) Engelmann, than any other plant material. Probing locations of B. occiduus and Blissus leucopterus leucopterus (Say) were similar on both B. occiduus-resistant and susceptible buffalograsses and KS94 sorghum, Sorghum bicolor (L.) Moench (B. occiduus-resistant, B. l. leucopterus-resistant). However, on 'Wheatland' sorghum (B. occiduus-resistant, B. l. leucopterus-susceptible), stylet tracts of B. l. leucopterus most often terminated in the bundle sheath cells, whereas those of B. occiduus generally terminated in the vascular tissues.

Animals↗
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↗
PubMed1989

Combined effects of laser and fluoride on acid resistance of human dental enamel.

Specimens of human dental enamel were topically applied with solutions of sodium fluoride (NaF) or acidulated phosphate fluoride (APF) before and after laser irradiation. APF application after laser irradiation caused a remarkable increase in acid resistance of the enamel, while APF application before laser irradiation showed a lesser effect, similar to either APF treatment alone or laser irradiation alone. These results were consistent with observations made using a scanning electron microscope. APF application after laser irradiation produced a greater fluoride uptake in the enamel than APF application before laser irradiation, as shown by electron probe microanalyzer. NaF application caused lesser acid resistance and lesser fluoride uptake than APF application, even when the enamel was treated with laser irradiation.

Acid Etching, Dental↗
PubMed2001

Phase, compositional, and morphological changes of human dentin after Nd:YAG laser treatment.

Although techniques for repairing root fracture have been proposed, the prognosis is generally poor. If the fusion of a root fracture by laser is possible, it will offer an alternative to extraction. Our group has attempted to use lasers to fuse a low melting-point bioactive glass to fractured dentin. This report is focused on the phase, compositional, and morphological changes observed by means of X-ray diffractometer, Fourier transforming infrared spectroscopy, and scanning electron microscopy-energy dispersive X-ray spectroscopy in human dentin after exposure to Nd:YAG laser. The irradiation energies were from 150 mJ/ pulse-10 pps-4 s to 150 mJ/pulse-30 pps-4 s. After exposure to Nd:YAG laser, dentin showed four peaks on the X-ray diffractometer that corresponding to a-tricalcium phosphate (TCP) and beta-TCP at 20 = 30.78 degrees/34.21 degrees and 32.47 degrees/33.05 degrees, respectively. The peaks of a-TCP and beta-TCP gradually increased in intensity with the elevation of irradiation energy. In Fourier transforming infrared analysis, two absorption bands at 2200 cm(-1) and 2015 cm(-1) could be traced on dentin treated by Nd:YAG laser with the irradiation energies beyond 150 mJ/pulse-10 pps-4 s. The energy dispersive X-ray results showed that the calcium/phosphorus ratios of the irradiated area proportionally increased with the elevation of irradiation energy. The laser energies of 150 mJ/ pulse-30 pps-4 s and 150 mJ/pulse-20 pps-4 s could result in the a-TCP formation and collagen breakdown. However, the formation of glass-like melted substances without a-TCP at the irradiated site was induced by the energy output of 150 mJ/ pulse-10 pps-4 s. Scanning electron micrographs also revealed that the laser energy of 150 mJ/ pulse-10 pps-4 s was sufficient to prompt melting and recrystallization of dentin crystals without cracking. Therefore, we suggest that the irradiation energy of Nd:YAG laser used to fuse a low melting-point bioactive glass to dentin is 150 mJ/ pulse-10 pps-4 s.

Aluminum Silicates↗
PubMedDate not supplied

Idiopathic calcinosis of the scrotum: scanning electron microscopic study with X-ray microanalysis.

In a 31-year-old man 12 nodules up to 1 cm in diameter were observed in the scrotum; these had developed over 3 years. Energy-dispersive x-ray analysis of the dermal foci showed a high content of calcium and phosphorus even in nodules smaller than 1 mm in diameter. No increased mineral deposition was observed in the surrounding connective tissue, however. Scanning electron microscopy revealed finely granulated crystals, and cellular remnants giving rise to development of calcified nodules were disclosed. The results support the hypothesis of a degenerative origin of scrotal calcinosis.

Adult↗
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↗
PubMed1985

Bioreactions at the tissue/hydroxyapatite interface.

The events at the hydroxyapatite implant material/tissue interface in the rat middle ear were studied by light microscopy, autoradiography, morphometry, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray microanalysis. Deposition of calcium, partially in the form of calcium phosphate, was found at the interface. Resorption of the implant material occurred as the result of mono- and multinuclear phagocyte activity. Resorption decreased 6 mnth after the operation, possibly due to the decreasing number of phagocytes at the interface and the increasing amount of bone in the macropores.

Animals↗
PubMed1989

Analyses of the tidemark on human femoral heads. I. Histochemical, ultrastructural and microanalytic characterization of the normal structure of the intercartilaginous junction.

The tidemark as a boundary between non-calcified and calcified articular cartilage has a complicated structure and fulfils various physiological functions. 25 human femoral heads from healthy joints were examined. In non-decalcified preparations three structural components of the tidemark were demarcated: (1) the PAS-positive, proteoglycan-containing tidemark line adjacent to the basal cartilage, (2) the sublinear light-coloured zone and (3) the demarcation line to the calcified cartilage. Using scanning electron microscopy, the tidemark was characterized as an electron-dense impression between hyaline and calcified cartilage. The presence of specific architecture and orientation of collagenous fibres could not be shown. Concentrations of calcium, phosphorus and sulphur could not be detected in the tidemark by means of an X-ray microanalyzer. A morphological model of the tidemark region was established, which represents the intercartilaginous junction as a double layer of substantially and functionally different surfaces.

Adult↗
PubMed1995

Otoconia on the vestibular dark cells of the ampullar areas.

Morphological and metabolic differences in the otoconia on vestibular dark cells of the ampullar area before and after streptomycin treatment were studied by scanning electron microscopy and X-ray microanalyser. Young adult pigmented guinea pigs were used in this study. In the control group, distribution of the otoconia showed a regular pattern. In the SM group the otoconia decreased in numbers and the regularity of the distribution pattern seemed to disappear. Calcium content of the otoconia in SM group also decreased. From these findings, it was concluded that SM might affect not only the sensory and supporting cells but also the vestibular dark cells.

Animals↗
PubMed1981

Analytical scanning electron microscopy and x-ray microdiffractometry of renal calculi using etched plastic sections.

We describe the technique and illustrate results of renal calculi analyses utilizing correlative analytical scanning electron microscopy and x-ray microdiffractometry on the same 100 micrometer Spurr embedded sections. Essential to the technique is the employment of an extremely sensitive x-ray microdiffractometer, and for morphological analysis, pretreatment of the sections with a sodium ethoxide etching solution. This technique facilitates more precise identification of crystalline constituents especially calcium apatite and magnesium ammonium phosphate hexahydrate (struvite). Further, the technique permits detection and mapping of both crystalline and amorphous constituents within calculi.

Calcium Oxalate↗
PubMed2006

Topographic, electrochemical, and optical images captured using standing approach mode scanning electrochemical/optical microscopy.

We developed a high-resolution scanning electrochemical microscope (SECM) for the characterization of various biological materials. Electrode probes were fabricated by Ti/Pt sputtering followed by parylene C-vapor deposition polymerization on the pulled optical fiber or glass capillary. The effective electrode radius estimated from the cyclic voltammogram of ferrocyanide was found to be 35 nm. The optical aperture size was less than 170 nm, which was confirmed from the cross section of the near-field scanning optical microscope (NSOM) image of the quantum dot (QD) particles with diameters in the range of 10-15 nm. The feedback mechanism controlling the probe-sample distance was improved by vertically moving the probe by 0.1-3 microm to reduce the damage to the samples. This feedback mode, defined as "standing approach (STA) mode" (Yamada, H.; Fukumoto, H.; Yokoyama, T.; Koike, T. Anal. Chem. 2005, 77, 1785-1790), has allowed the simultaneous electrochemical and topographic imaging of the axons and cell body of a single PC12 cell under physiological conditions for the first time. STA-mode feedback imaging functions better than tip-sample regulation by the conventionally available AFM. For example, polystyrene beads (diameter approximately 6 microm) was imaged using the STA-mode SECM, whereas imaging was not possible using a conventional AFM instrument.

Animals↗
PubMed1990

The in vivo auto-oxidation of polyether polyurethane by metal ions.

The first large scale use of polyether polyurethane elastomers in long term human implants was as insulation for cardiac and neurologic pacing leads. While the performance of these polymers has generally been very good over a 14-year period, several failure mechanisms have been discovered that involve interactions between the devices, materials and the body. One of these is auto-oxidation of soft segment ether through the intermediate action of certain transition metal ions, derived from conductor wires by corrosion processes. Biologically produced oxidants appear to be an accelerating factor. In this study, Pellethane 2363-80A tubing containing conductor coils or mandrels of various metals or controls were implanted in rabbits. Explants were analyzed as a function of implant time by optical and scanning electron microscopy, electron dispersive analysis by X-ray, stress-strain, FTIR, GPC and AA spectrophotometry. Only cobalt produced bulk oxidative degradation while surface damage was found in the presence of cobalt bearing alloys. No evidence of significant auto-oxidation was found in the presence of silver, nickel, chromium, molybdenum, iron, titanium, platinum, 304 stainless steel, glass or empty tubing. The combination of polyether polyurethane and metals (especially those containing cobalt) in an implantable device must be carefully evaluated for biostability prior to human use.

Biocompatible Materials↗
PubMed1990

Clinical and histological findings in ligature-induced experimental periodontitis in dogs. A pilot study.

Prior to experimental periodontal regenerative procedures in animals, the process of destruction due to periodontitis is often simulated by placing ligatures around the necks of teeth. 2 models, one using cotton floss ligatures and the other elastic rubber ligatures, have been widely used. The aim of this study was to compare these 2 methods using clinical and histometric criteria. Premolars on both sides of the mandibular jaw were used in 2 beagle dogs. Periodontal tissue breakdown was induced during a 48-day period using cotton floss ligatures on one side of the mandible and contra-laterally by elastic rubber ligatures. At weekly intervals, the ligatures were changed and pocket depth and loss of probing attachment were recorded. All the ligatures were removed after 7 weeks. The animals were fed a soft, plaque-promoting diet during the experimental period. 20 days after ligature removal, the teeth were hemisected and the 2 roots extracted. From each tooth, 1 root was prepared for scanning electron microscopy and one for light microscopy. At the time of extraction, no differences regarding pocket depth or probing attachment level were found between the 2 groups. Root resorption was observed in all elastic ligature teeth, whereas only minor alterations at the root surface were observed on cotton ligature teeth. This finding may be of particular interest to investigators designing studies evaluating the healing sequalae of regenerative surgery in animals. As was observed in this study, root resorption can already be present in the pre-experimental phase of periodontal tissue breakdown, particularly if elastic ligatures are used.

Animals↗