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PubMed2000

Cytological changes in chlorhexidine-resistant isolates of Pseudomonas stutzeri.

Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy-dispersive analysis of X-ray (EDAX) have been used to examine chlorhexidine diacetate (CHA)-sensitive and -resistant isolates of Pseudomonas stutzeri and to determine the effects of CHA on the cells. Significant differences were observed in the structure, size and elemental composition of CHA-sensitive and -resistant cells. Treatment with CHA produced considerably greater changes in CHA-sensitive cells, with widespread peeling of the outer membrane, a substantial loss of cytoplasmic electron-dense material and extensive lysis. Cells from the resistant isolates showed no blebbing of the outer membrane and no structural damage. X-ray mapping confirmed the difference in CHA uptake between CHA-sensitive and CHA-resistant cells. It is proposed that changes in the outer membrane form a major mechanism of resistance to CHA in P. stutzeri.

Chlorhexidine↗
PubMed1987

Treatment of dentin with stannous fluoride--SEM and electron microprobe study.

The effect of SnF2-treatment of dentin surfaces was investigated by means of scanning electron microscopy (SEM) and electron microprobe analysis. Human dentin was treated with aqueous SnF2 solutions of concentrations varying from 1 to 10%. The treatment periods lasted for 1, 5, 10, or 60 min. Both tin and fluoride were identified on the surfaces. The concentration varied depending on the extensiveness of the treatment. Immersion in 1 M KOH for 15 h removed both tin and fluoride from the surfaces. This reaction was not observed after immersion in H2O for the same time period. Examination of the SnF2-treated dentin surfaces showed a dense layer of globular particles and in addition some larger particles. The dentinal tubules were totally covered even after the treatment with the lowest concentration of SnF2. Deposition of tin- and fluoride-containing globules on dentin surfaces may be of clinical interest. This layer may have importance both for the caries resistance of dentin and for hypersensitivity reactions.

Dental Caries↗
PubMed1981

Application of scanning electron microscopy to x-ray analysis of frozen-hydrated sections. II. Analysis of standard solutions and artificial electrolyte gradients.

New specimen handling and analytic techniques for the application of x-ray microanalysis to studies of cell and organ biology have been recently described (Saubermann et al., 1981, J. Cell Biol. 88:257-267). Based on these techniques, absolute quantitative standardization has been established through x-ray analysis of frozen-hydrated and then dried sections of independently measured standard solutions of elements. These experiments demonstrate that the specific techniques employed have a probable error of less than 10%. Artificial electrolyte gradients established in gelatin were subjected to analysis to determine whether there was elemental displacement under non-membrane-limited conditions at the temperatures employed for sectioning (-30 degrees to -40 degrees C). No significant difference was observed between such gradients in serial sections cut at -30 degrees and -80 degrees C. Similarly, no additional ice-crystal-damage artifact was found in sections cut at -30 degrees C when compared with sections cut at -80 degrees C. Thus, in terms of ice-crystal size, gradient maintenance, and compartmental differentiation, cryosectioning at -30 degrees to -40 degrees C was not associated with redistribution incompatible with 1- to 2-micrometers spatial resolution, and absolute measurements of elemental concentration were practical within regions of this size.

Chlorides↗
PubMed2005

Interface evaluation after manual and ultrasonic insertion of standardized class I inlays using composite resin materials of different viscosity.

OBJECTIVE: The aim of the present study was to investigate the effect of manual and ultrasonic insertion of standardized class I inlays (Cerana) using three composite resin materials of different viscosity (Tetric Flow, Tetric, and Tetric Ceram) on time to seat inlays, film thickness, and filler distribution within the materials. METHODS: In a preliminary test, mean loads for manual and ultrasonic insertion were measured using the high viscosity composite resin material (Tetric Ceram). These loads were then applied with all composite resin materials to evaluate the times required to seat the inlays. In addition, film thickness was assessed using scanning electron microscopy, and filler distribution (wt% silicon, barium, ytterbium) was monitored using energy-dispersive spectroscopy. RESULTS: Ultrasonic insertion significantly reduced mean load applied to seat inlays (6.4+/-1.4 N; mean+/-SD) as compared to manual insertion (18.9+/-3.1 N; p < 0.001). Using an ultrasonic device, times for insertion values were significantly lower in the high and medium viscosity composite resin material groups compared to manual insertion (p < 0.05). The widest film thickness was recorded for the high viscosity composite resin material in combination with manual insertion (p < 0.05). However, when ultrasound was applied, there was no difference in film thickness between the three materials at any levels. Furthermore, the analysis of filler distribution revealed no significant differences between groups. CONCLUSION: Highly filled viscous composite resin materials may be used in combination with the ultrasonic insertion technique without untoward effects on film thickness or filler distribution.

Barium↗
PubMed2003

Resorbable and nonresorbable hydroxyapatite granules as bone graft substitutes in rabbit cortical defects.

BACKGROUND: The use of various synthetic calcium phosphate compositions for the promotion of bone in bone defects is of potential interest because such materials may be tailor made and may bond to bone. There is yet an inadequate knowledge of the role of calcium phosphate composition and resorbability for the bone response. PURPOSE: The aim of the present study was to compare the ability of resorbable versus nonresorbable hydroxyapatite (HA) granules to promote new bone formation in cortical bone defects. Resorbable and nonresorbable HA granules, used as bone graft substitutes, were evaluated after 6 weeks and 3 months in the rabbit tibia. Circular defects (diameter 5.0 mm) were made in both tibias of 18 New Zealand white rabbits. The 36 defects were divided into three groups (six observations per group and time, respectively). The first group was augmented with resorbable HA granules, the second group was augmented with ceramic nonresorbable HA granules, and the third group was left without augmentation (control). The animals were killed after 6 weeks and 3 months, and the tissue was evaluated with light microscopic (LM) morphology and morphometry, scanning electron microscopy (SEM), and energy dispersive x-ray analysis (EDX). RESULTS: After 3 months LM morphometry revealed significantly more newly formed bone in the two HA augmented groups compared with that in the control. A close contact was found between both kinds of HA granules and new bone as viewed with light microscopy and SEM. A relatively slow degradation process was indicated by the small reduction of the total granule area in the cortical defects. However, LM observations showed a change of granule form. Pilot experiments using SEM-EDX indicate that Ca and P contents had decreased in the resorbable HA granules between 6 weeks and 3 months. Further, a higher content of Ca and P was found in the newly formed bone close to granules, in comparison with more distant newly formed bone. CONCLUSIONS: Our results suggest that both resorbable and nonresorbable HA granules promote new bone formation in rabbit cortical defects, which does not occur in control defects.

Absorbable Implants↗
PubMed2007

Effect of ultraviolet B radiation on the absorption characteristics of various intraocular lenses.

BACKGROUND: The aim of this study was to determine the effect of ultraviolet B (UVB) exposure on UV filters of various intraocular lenses (IOLs). METHODS: Eight samples each of the hydrophobic acrylic, hydrophilic acrylic and silicone IOLs were used. Four IOLs of each type was selected randomly as the control group while the remaining four IOLs of each type were exposed to a UVB dose of 1.4 J/cm(2) (2.40 mW/cm(2)) for 9.45 min, two times with a 4-week interval. IOLs were evaluated for any sign of opacification under microscope weekly. After a follow-up period of 16 weeks, spectrometry for UV filter absorption rates, scanning electron microscopy for deposit formation and energy dispersive X-ray analysis for elemental composition were performed for all IOLs, and findings of the control group IOLs were compared with those of the UVB-exposed IOLs. All these procedures were done at the Department of Ophthalmology, Faculty of Medicine, Dokuz Eylul University. RESULTS: All the IOLs were free of any opacification during the follow-up period. Spectrometric analysis of their UV filters revealed a change in absorption rates in the hydrophilic acrylic and silicone IOLs compared to the control IOLs of the same type. Only the hydrophobic acrylic IOLs preserved the same UV absorption curve after UVB exposure. CONCLUSION: The pathogenesis of IOL opacification is still undetermined. Some reports claimed that the UV light was the responsible factor. Our experimental study revealed that high doses of UVB did not cause any opacification though they impaired the function of UV filters of the hydrophilic acrylic and silicone IOLs.

Acrylic Resins↗
PubMed2006

Scanning electron microscopic analysis of acrylic intraocular lenses for microincision cataract surgery.

PURPOSE: To analyze the surface quality before and after folding of 2 intraocular lens (IOL) models designed for microincision cataract surgery. SETTING: Eye Clinic and Department of Human Pathology and Oncology, University of Florence, Florence, Italy. METHODS: Two IOL models now available for sub-2.0 mm microincision were studied: UltraChoice 1.0 Rollable ThinLens (ultrathin lens by ThinOptX) and AcriSmart (foldable lens by AcriTec). Eight IOLs of each model were examined. Scanning electron microscopy (SEM) was performed before and after IOL folding with a dedicated injector. Special attention was given to the optic surface and edges, the optic-haptic junction, and the haptic itself. RESULTS: Initially, the surface quality of IOLs was evaluated before folding. On SEM, smooth and homogeneous optic and haptic surfaces were revealed in both IOL models with no surplus material or molding flashes; edge finish of all optics showed no evidence of ridges. The IOL surfaces were evaluated after insertion into their injectors and after ejection at room temperature. After folding, the microincision IOLs showed no sign of surface alteration, probably because of their high water content, which makes these IOLs soft and flexible. CONCLUSIONS: Visual results and long-term biocompatibility of the IOLs are influenced by surface properties. In recent years, there has been a trend toward microincision cataract surgery. Our study shows that the 2 IOL models now available for sub-2.0 mm microincision have acceptable surface properties.

Acrylic Resins↗
PubMed2004

Calcium crystals in the anther of Petunia: the existence and biological significance in the pollination process.

Using an X-ray microanalysis system fitted with variable-pressure scanning electron microscopy, we noted that many calcium crystals accumulated under the stomium in the anther of Petunia. When the anther was dehisced and pollen grains were released from the stomata, the calcium crystals adhered to pollen grains and moved to the stigma together with pollen grains. In contrast, an X-ray microanalysis of the stigma surface before pollination detected no calcium emission on the stigma surface. Furthermore, pollen germination and pollen tube growth in medium without Ca occurred as in complete medium. However, after the pollen grains had been washed with abundant germination medium without calcium, pollen germination in the medium without Ca was inhibited. These results show that the calcium crystals dissolved in the aqueous drop under the exudate on the stigma and supplied calcium ions for pollen germination. In addition, calcium crystals were produced not only in the anther of Petunia but also in Nicotiana, suggesting that calcium crystals supply pollen grains with the calcium ions required for pollen germination and serve to improve reproduction efficiency in Solanaceae.

Calcium↗
PubMed2006

Whole insect and mammalian embryo imaging with confocal microscopy: morphology and apoptosis.

BACKGROUND: After fluorochromes are incorporated into cells, tissues, and organisms, confocal microscopy can be used to observe three-dimensional structures. LysoTracker Red (LT) is a paraformaldehyde fixable probe that concentrates into acidic compartments of cells and indicates regions of high lysosomal activity and phagocytosis, which both correlate to apoptosis activity. LT has been shown to be an indicator of apoptotic cell death which is correlated to other standard apoptotic assays. METHODS: The mammalian samples were stained with LT, fixed with paraformaldehyde/glutaraldehyde, dehydrated with methanol (MEOH), and cleared with benzyl alcohol/benzyl benzoate (BABB). Following this treatment, the tissues were nearly transparent. Mosquitoes were fixed with MEOH and stained with propidium iodide. Next the tissues were dehydrated with MEOH and cleared with BABB. RESULTS: Tissues as thick as 500 microm can be visualized after clearing with BABB. LT staining revealed apoptotic regions in mammalian limbs, fetuses, and embryos. Morphological observation of insect tissue consisted of combining autofluorescence with either nucleic acid staining (either propidium iodide or ethidium bromide). CONCLUSIONS: The use of BABB matches the RI of the tissue within the suspending medium. It helps in increasing the penetration of laser light in a confocal microscope by reducing the amount of light scattering artifacts and allows for the visualization of morphology in thick tissues. LT is a probe that stains the acid regions of tissues and cells and has been correlated to apoptosis. Morphological features of a tissue or organism (embryo, mosquito larvae) can be elucidated by fixation aldehydes, autofluorescence, and red-emitting probes. This sample preparation procedure with optimization of confocal laser scanning microscopy allowed for the detection and visualization of apoptosis in fetal limbs and embryos which were approximately 500-microm thick.

Amines↗
PubMed2004

Characteristics of manganese-coated sand using SEM and EDAX analysis.

"Manganese-coated sand" is a type of silica medium coated with manganese oxides, formed from the sorption of manganese oxides during long-term filtration via the process of rapid sand filtration, followed by aeration in a water treatment plant. Locally available manganese-coated sand, both for packing and as a byproduct of filtration processes for water treatment plants in Taiwan, was found to be a low-cost and promising adsorbent for removal of Mn(2+) from raw water. This study was conducted to build the basic data for coating hydrated manganese oxide on the sand surface to utilize the adsorbent properties of the coating and the filtration properties of the sand. In this study, gas adsorption porosimetry and scanning electron microscopy analyses were used to investigate the surface properties of the coated layer. An energy dispersive X-ray (EDAX) technique of analysis was used to characterize metal adsorption sites on a manganese-coated sand surface. Results indicated that manganese-coated sand had more micropores and higher specific surface area, owing to attachment of manganese sand. Manganese ions penetrated into the micropores and mesopores of manganese oxide on a sandy surface; regeneration of manganese-coated sand could be achieved by soaking with pH < 2.0 acid solution. Results of EDAX analysis showed that the interfacial layer constructed the interface of manganese-coated sand. Acid and alkali resistance tests interpret a wide application range of pH for manganese-coated sand, and general temperature conditions do not affect the performance of this sand. Manganese-coated sand is potentially suitable for application as a packed bed for treatment of heavy metals from water. The results of this study can also benefit plant operational capacity data for engineering design.

Adsorption↗
PubMed2003

Ultrastructural analysis of salivary calculus in combination with X-ray microanalysis.

Ultrastructural studies of salivary calculi were performed. Scanning electron microscopic examination of the calculi revealed lamellar and concentric structures. Granular or globular structures and pyramid structures were found on the surface of the calculi, and in some cases a scaly structure corresponding to fiber and bacteria was recognized. X-ray microanalysis showed the main constitutes of the calculi to be Ca and P. Transmission electron microscopic examination revealed a fine fibrous structure near the degenerated organelles, and analyses of the structure by electron diffraction revealed hydroxyapatite. Calcification was found around the degenerative organelles in the form of lipid-like structures, mitochondria, lysosomes, and microbial structures. Judging from our results, as one of the processes leading to calculi formation, it is speculated that degenerative substances are emitted by saliva, by some phenomenon, and calcification around these substances then occurs, contributing to the formation of calculi.

Electron Probe Microanalysis↗
PubMed1994

Evaluation of distraction osteogenesis by scanning electron microscopy.

A model of bifocal distraction osteogenesis in the canine model was used to assess and quantitate the mineral content of the newly forming bone within the canine mandible. A 2-cm defect was created in the body of the mandible, and after a posterior osteotomy, the transport disk was advanced at 0.25 mm per 8 hours for 21 days and then held in rigid fixation for an additional week. As a control for this study, three additional dogs underwent the same procedure with the exception that the transport disk was not advanced. Electron dispersive spectroscopy analysis was performed on the newly formed regenerate bone and compared with areas of existing cortical bone of both the transport disk and the mandible. In the control model, special note was made of the pericortical callus at the osteotomy site as well as of the regenerative bone that filled the 2-cm defect in the body of the mandible. Calcium/phosphorous ratios were used to assess the composition of the mineralized regions of the mandible. The regenerate bone that filled the defect and the mineralized callus surrounding the site of osteoclasis in the control mandible were significantly different in composition when compared with the regenerate bone that formed during distraction osteogenesis. This suggests that distraction osteogenesis may effect an initial matrix production that is more similar in composition to the mature cortical bone from which it was derived than does periosteal regeneration and filling of an osseous defect.

Animals↗
PubMed1990

Limitations of ZAF correction factors in the determination of calcium/phosphorus ratios: important forensic science considerations relevant to the analysis of bone fragments using scanning electron microscopy and energy-dispersive x-ray microanalysis.

A series of calcium phosphate standards having calcium/phosphorus (Ca/P) molar ratios of 0.50, 1.00, 1.50, and 1.67, respectively, was prepared for bulk specimen analysis using scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDXA). The standards were mounted on carbon planchettes as either pure crystals or crystals embedded in epoxy resin. Ten different samples of each embedded and non-embedded standard were analyzed in a JEOL 100 CX electron microscope interfaced with a Kevex 8000 EDXA system using a lithium-drifted silicon detector and a multichannel analyzer. The Ca/P ratios were determined by calculating both net peak intensities without matrix corrections and atomic kappa-ratios using the MAGIC V computer program with ZAF correction factors for quantitative analysis. There was such extensive absorption of phosphorus X-rays in standards embedded in an epoxy matrix that the observed Ca/P ratios were statistically compatible with four different standards ranging in theoretical Ca/P ratios from 1.0 to 1.67. Although the non-embedded crystals showed a greater separation in the Ca/P ratios, both methods of preparation produced serious flaws in analysis. Direct application of the discovery of this caveat to the identification of suspected bone fragments for forensic science purposes is discussed.

Bone and Bones↗
PubMed1996

Hard tissue of teeth and their calcium and phosphate content in Ambystoma mexicanum (Urodela: Ambystomatidae).

The wall of the pulp cavity, fracture faces and the demineralized surfaces of teeth from larvae and adults of Ambystoma mexicanum were investigated by scanning electron microscopy (SEM). Calcium and phosphate contents were determined by microanalysis. The apical part of the tooth (crown, tooth apex) contains dentin canals. In the larva, these do not reach the enamel-dentin border but end below this border in front of a denser hard substance, possibly enameloid. The pedicel in the adult and the basal portion of the tooth in the larva (base) are without dentin canals. These parts of the teeth are characterized by longitudinally arranged collagen fibres as visualized on the demineralized surfaces. These observations indicate a congruency in early-larval and adult teeth between base and pedicel as well as apex and crown. This partition is also confirmed by the calcium and phosphate values which were identical in larvae and adults. Highest values are found in enamel and lowest values in the tooth-bearing bone. Calcium and phosphate content show a clear difference between dentin and the basal part of the tooth (pedicel and base). The ring-like dividing zone in the adult tooth is less well mineralized.

Ambystoma mexicanum↗
PubMed1997

Fractal analysis of beta-cyclodextrin-indomethacin particles compacted by ultrasound.

An association between indomethacin and beta-cyclodextrin (beta-CD) was obtained by compacting a 1:2 molar physical mixture by ultrasound. The product prepared by this technique was compared with the initial physical mixture and with materials having the same composition but prepared by a simple compaction and kneading process. The samples examined by scanning electron microscopy revealed morphological differences related to the methods of preparation. In particular the material obtained by ultrasound had a smooth surface and on milling produced particles of uniform size; moreover EDAX analysis (energy dispersion analysis by X-rays) also revealed a homogeneous distribution of the two components in each particle examined. Surface fractal dimension of the surface of these particles is very low, suggesting the presence of a regular and smooth surface whereas the sample obtained by kneading had a higher value. The reactive dimension related to dissolution was much higher than the corresponding surface dimension in all cases and had comparable values for all samples regardless of the techniques used. This behavior was attributed to the hydrophilicity of beta-CD, which levels the differences during dissolution and which could be originated by surface imperfections. Experimental results suggested that the material obtained by ultrasound had a dissolution rate comparable to that measured with the kneaded material. The use of ultrasound, however, can both reduce the production time and improve the homogeneity of the association between indomethacin and beta-CD.

Cyclodextrins↗
PubMed1986

Adipocyte development in primary rat cell cultures: a scanning electron microscopy study.

This study utilized scanning electron microscopy (SEM) techniques to observe primary cultures of stromal-vascular (SV) cells derived from postnatal rat inguinal adipose tissue. Cells were grown on collagen-coated, fibronectin-coated, or uncoated glass coverslips. Coverslips were normally fixed in glutaraldehyde, osmium tetroxide, dehydrated, and critical-point-dried. Other coverslips were frozen in isopentane (cooled in LN2) and dried or fixed in Baker's formalin for demonstration of inosine diphosphatase (IDPase) by X-ray microprobe analysis (XRMA). Adipocyte morphologies were similar on all substrates. At 2 days of culture, actin cables were detected extending from developing adipocytes. No difference in actin cable structure, cellular shape, or lipid accumulation was observed among the different substrates. Some stromal cells did not accumulate lipid but proliferated into a multilayer by 9 days in culture. Inosine diphosphatase was detected in the Golgi apparatus of developing adipocytes utilizing the technique of XRMA. This study demonstrates the potential for using SEM and XRMA techniques to define morphological features and cytochemical markers of adipocytes in vitro and the response of primary cultured rat SV cells to other attachment substrates.

Adipose Tissue↗
PubMed2001

Effects of erbium, chromium:YSGG laser irradiation on root surface: morphological and atomic analytical studies.

OBJECTIVE: The purpose of this study was to investigate the morphological and atomic changes on the root surface by stereoscopy, field emission-scanning electron microscopy (FE-SEM), and energy dispersive X-ray spectroscopy (SEM-EDX) after erbium, chromium:yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser irradiation in vitro. SUMMARY BACKGROUND DATA: There have been few reports on morphological and atomic analytical study on root surface by Er,Cr:YSGG laser irradiation. METHODS: Eighteen extracted human premolar and molar teeth were irradiated on root surfaces at a vertical position with water-air spray by an Er,Cr:YSGG laser at the parameter of 5.0 W and 20 Hz for 5 sec while moving. The samples were then morphologically observed by stereoscopy and FE-SEM and examined atomic-analytically by SEM-EDX. RESULTS: Craters having rough but clean surfaces and no melting or carbonization were observed in the samples. An atomic analytical examination showed that the calcium ratio to phosphorus showed no significant changes between the control and irradiated areas (p > 0.01). CONCLUSIONS: These results showed that the Er,Cr:YSGG laser has a good cutting effect on root surface and causes no burning or melting after laser irradiation.

Calcium↗
PubMed1996

A pilot study comparing screw-shaped implants. Surface analysis and histologic evaluation of bone healing.

The purpose of this study was to compare surface treatment and bone formation adjacent to 2 screw shaped implants of similar design manufactured by two different companies. The test implants were manufactured by SERF (Decines, France), while the controls were manufactured by Nobelpharma (Goteborg, Sweden). The surface of 3 standard 3.75 mm test and 3 standard 3.75 mm control implants were investigated by means of scanning electron microscopy (SEM), X-ray micro-analysis, electron spectroscopy for chemical analysis (ESCA) and surface topography analysis. There was a microscopic difference on the thread design (SEM). Test threads were flat at the edge, while controls appeared rounded at the edge of the threads. Tests and controls were made of commercially pure titanium, with a regular topography. Results of ESCA indicated that the carbon peak for SERF implants was slightly higher than for the Brånemark implants. 5 test and 5 control implants were installed into the epiphyseal head of the femur of 2 ewes using a standardized surgical technique. In order to stain the bone for histologic analysis, oxytetracycline injections were given 17 and 8 days before the animals were sacrificed. The animals were sacrificed 12 weeks after implant placement. Histomorphometric analysis indicated that there was an average bone to implant contact orf 68% for the test implants and 61% for the controls. There were no statistical differences between tests and controls. The preliminary results of this pilot study indicated that early bone healing for the 2 screw shaped implants investigated were similar.

Animals↗