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PubMed2000

Scanning electron microscopic analysis of skin resolution as an aid in identifying trauma in forensic investigations.

The forensic investigator is frequently confronted with cases that present with wounds and blunt force trauma. Presently, the forensic investigator depends upon previous experience and further investigative deduction of the crime scene to analyze these injuries. Although not readily apparent to the naked eye, many skin tissue injuries can be visualized with scanning electron microscopy (SEM). This study was designed to establish skin trauma resolution using SEM in various skin preparations. Tissue trauma was induced on leather, preserved skin, fresh skin, and living skin using dies of varying thread size. Calibrated pressure forces in pounds per square inch (psi) were applied and impressions made using vinyl polysiloxane. Positive replicas of the tissues were prepared for SEM using isocyanate resin. After sputter coating the cast with 35 nm of gold-palladium, electron micrographs were generated using a Jeol JSM-5310LV scanning electron microscope. To establish resolution, thread widths of 52, 104, and 208 threads per inch (tpi) and trauma forces of 150, 200, and 250 psi were used to produce the impressions. Microgrooves that were identified on the die threads were analyzed. The optimum pressure for resolution studies was 150 psi using the 52 tpi die on the leather sample (4.67 +/- 0.88 microm, p = 0.046 and 0.025, respectively, by ANOVA). The resolution was compared to that of leather using preserved, fresh, and living skin. The resolution in preserved and fresh skin was less than for leather (9.00 +/- 1.73 and 10.5 +/- 4.5 versus 4.67 +/- 0.88 microm, p = 0.09 and p = 0.20, respectively). Living skin resolution was 3 microm at 52 tpi and 100 psi. Various implements of blunt force trauma were also examined using the leather sample. Time after trauma resolution was examined at 0 (3 microm), 5 (6 microm), 10 (8 microm), and 20 (9 microm) min in living tissue. A comparison between the microgrooves on the die replicas and the tissue trauma impressions revealed striking agreement for both linearity and resolution. Analysis of the microgrooves suggests that discrete morphological characteristics are seen in skin tissue traumas. This method could expand the tools available for the forensic investigation of blunt force trauma.

Cadaver↗

PubMed1994

Silicate pneumoconiosis in pigs: optical and scanning electron microscopical investigations with X-ray microanalysis.

Four cases of silicate pneumoconiosis are described in pigs raised near several chalk quarries and two cement works. The pulmonary changes were characterized by thickened alveolar septa, resulting in distorted airspaces, and small foci of initial fibrosis. In the bronchiolar and alveolar sites, as in the interstitium, free and intracytoplasmic dust was detected. An energy dispersive X-ray microanalysis coupled with a scanning electron microscope revealed that this dust was composed mainly of silicon, calcium, potassium, sulphur, aluminium and iron. In lung-associated lymph nodes, severe lymphoid cell depletion and dilatation of peritrabecular and subcapsular sinuses were constant findings. The inorganic material found in the lymph nodes contained the elements listed above. Air samples from the same geographical area revealed particulate pollutants, the qualitative features of which were similar to those found in lung and lymph nodal tissue. It is concluded that domestic animals raised in polluted environmental conditions represent an important biological source from which helpful data may be obtained for assessing risks to human health.

Animals↗

PubMed1996

A scanning electron microscopic study of trabeculae in osteoporotic femoral head.

OBJECTIVE: To investigate osteoclastic resorption in trabeculae of osteoporotic femoral head. METHODS: Osteoporotic femoral heads were collected from 7 aged women with an average age of 72.4 years, who underwent endoprosthetic replacement for intracapsular hip fracture. Femoral head trabeculae from 3 young adults killed in traffic accidents served as control. The two types of specimens were processed and studied under scanning electron microscope. RESULTS: The trabeculae of femoral head formed round or roundish arch structure. The columnar trabeculae of femoral head in the aged women showed overt osteoclastic resorption, manifested in thinning, tapering and perforation, resulting in formation of icicle-like trabeculae, which then became rounded, lost height and eventually turned into small tubercle. As a result, the inter-trabecular space enlarged markedly. Under high magnification, the trabeculae could be discerned oval, narrow oval or spindle-shaped. Howship resorption lacunae, which varied in size, depth and content, but all revealed punched-out margin. During bone resorption, the inorganic and organic components were successively resorbed. In the Howship lacunae and surrounding areas, newly formed collagen fibrils and bone tissues emerged, signifying reversal and new bone formation phases after bone resorption phase. CONCLUSION: Osteoclastic resorption markedly compromises the structural integrity and strength of the trabeculae of the arch structure of the femoral head in the aged women.

Age Factors↗

PubMed2000

The reduction of the beam gas interactions in the variable pressure scanning electron microscope with the use of helium gas

This paper presents experimental observations on electron scattering by gases (helium and air) in the specimen chamber of a variable pressure scanning electron microscope. It shows an important reduction of the beam scattering with the use of helium gas, and the consequences for the x-ray microanalysis are discussed.

Journal Article↗

PubMed1989

The effectiveness of different endodontic irrigation procedures on the removal of the smear layer: a scanning electron microscopic study.

To compare the effectiveness of different irrigation procedures on the removal of the smear layer, 40 curved canals were manually prepared in vitro under copious irrigation with 3 per cent NaOCl. Ten canals served as controls. The remaining 30 were equally distributed in three experimental groups and subsequently irrigated with the following: ultrasound with NaOCl; EDTA; ultrasound with EDTA. In the scanning electron microscope, the appearance of the smear layer was rated over the distribution of dentinal tubule openings for the coronal, middle and apical segments of the canals. Irrigation with NaOCl produced consistently smeared surfaces. Ultrasonic stirring of NaOCl removed the smear layer moderately, while EDTA produced almost smear-free surfaces. Ultrasound in association with EDTA did not enhance the dissolving capability of this chelating agent. A definite decline in the efficiency of the irrigation procedures was also observed along the apical part of the canals.

Dentin↗

PubMed1993

Scanning electron microscopic observation on the dentin surface of rat enamel-free areas.

Formation of the enamel covering on the dentin of the tooth crown is thought to depend upon the dentin surface structure during the early stages of enamel development. For this reason, observations were made of the dentin surfaces of both the enamel-free area (EFA) and the region beneath the enamel area. After treatment with sodium hypochlorite and formic acid, scanning electron microscope observations were made of the EFA surface and the exposed dentin surface beneath the enamel of unerupted rat mandibular first molars. Cone-like projections consisting of matrix fibers were observed on the dentin surface covered with the enamel. These cone-like projections formed continuous ridges that connected with the network structure. At the concavities of these network structures these projections were distributed sparsely. Instead of the cone-like projections, the matrix fibers formed a coarse network structure along the surface at the EFA.

Amelogenesis↗

PubMed2000

Effects of titanium surfaces blasted with TiO2 particles on the initial attachment of cells derived from human mandibular bone. A scanning electron microscopic and histomorphometric analysis.

This study was performed to determine the effect of commercially pure titanium surfaces blasted with TiO2 particles on the biological responses of cells derived from human mandibular bone. The morphology and attachment of those cells were investigated on turned titanium surfaces (control) and surfaces blasted with 45 microns (standard), 45-63 microns, and 63-90 microns TiO2 particles. The surfaces were analyzed in a scanning electron microscope. Based on surface analyses reported elsewhere, the turned samples had the smoothest surfaces and the roughest were those blasted with the largest particles (63-90 microns). The cell profile areas were measured using a semi-automatic interactive image analyzer. The attachment was determined as a ratio of the area of cell profiles and the total micrograph area and was expressed as percentage of attachment. Morphologically, the cells were heterogeneous. In general, the cells had spread well on all titanium surfaces, indicating good attachment to both smooth and rough surfaces. After 1, 3 and 6 h, the percentage of cell attachment did not differ significantly between the surfaces blasted with 63-90 microns and the turned surfaces, but was significantly lower on the surfaces blasted with 45 microns or 45-63 microns particles. After 24 h the surfaces blasted with 63-90 microns particles had a higher rate of cell attachment than all the other surfaces including the controls. It is concluded that attachment and growth of cells originating from human mandibular bone in vitro, are influenced by the micro-texture of the implant surface.

Cell Adhesion↗

PubMed1981

Haemostatic clot formation at anastomosis of synthetic venous graft in defibrinogenated dogs: a scanning electron microscopic study.

A segment of the inferior vena cava was replaced by an expanded polytetrafluoroethylene graft in 13 dogs. Five of them served as a control group, while the other 8 were moderately or severely defibrinogenated with subcutaneous batroxobin. Plasma fibrinogen decreased to extremely low values throughout the experiment in the defibrinogenated dogs except in the moderately treated group in which it temporarily rose to 0.72-0.87 g/l on the first postoperative day. Scanning electron microscopic observations of the haemostatic clot formed at the anastomoses of the graft revealed no significant morphological differences in platelet adhesion and/or aggregation between the three groups. These findings confirmed that platelets play a key role in primary haemostasis during defibrinogenation. The fibrin network was slightly diminished and only short fibrin filaments could be seen in the moderately and severely defibrinogenated groups respectively. These differences in composition of the clots are discussed in relation to their haemostatic capacity.

Animals↗

PubMed2000

Direct measurement of electron beam scattering in the environmental scanning electron microscope using phosphor imaging plates

Phosphor imaging plate technology has made it possible to directly image the distribution of primary beam electrons and scattered electrons in the environmental scanning electron microscope. The phosphor plate is exposed under electron scattering conditions in the microscope chamber. When processed, the electron intensity distribution is displayed as a digital image. The image is a visual representation of the electron probe and skirt and may provide the basis for a more accurate model.

Journal Article↗

PubMed2002

Histochemical, immunohistological and scanning electron microscope analysis of tissue retained on spontaneously extruded ventilation tubes.

The aim of this study was to analyse the tissue surrounding prematurely extruded ventilation tubes (grommets). Thirty-one ventilation tubes, including 21 Shah and six Shepherd tubes, that had been extruded naturally into the ear canal were examined. After formalin fixation, material adhering to the tubes was retrieved and processed to paraffin wax. Five tubes were processed for scanning electron microscope (SEM) analysis. Sections were stained using histochemical methods for collagen, keratin and keratohyaline. In addition, the presence of collagen (type I and III), keratin, vimentin, fibronectin, tenascin, factor VIII-related antigen, CD31 and CD45 was tested for by immunohistochemistry. Results showed that all specimens consisted of an acellular fibrous material, oriented in concentric rings parallel to the tube surface that was often associated with small collections of CD45+ inflammatory cells. Two specimens contained collagen that was detectable by histochemical and immunohistological methods. Twelve specimens contained identifiable desquamated epithelial cells containing keratin and keratohyaline. Only one specimen stained positively for connective tissue markers (vimentin, fibrous fibronectin, tenascin) or showed the presence of vascular epithelium. SEM revealed adherent clusters or sheets of plate-like structures, consistent with the presence of epithelial squames, on three of the five ventilation tubes examined. It is concluded that tissue retained on extruded grommets consists of orthokeratinitizing epithelium infiltrated by inflammatory cells, a finding that is consistent with the theory that tube extrusion occurs as a result of squamous epithelial proliferation, medial migration, differentiation and desquamation.

Biomarkers↗

PubMed2003

[Degradation of copper IUDs in utero. The process of metallic corrosion. A scanning electron microscope study].

OBJECTIVE: The present investigation was carried out in order to study the process of metallic corrosion of copper IUD's in utero, to precise its dynamics and location along the IUD and to appraise the influence of eventual calcareous deposition. MATERIAL AND METHODS: A total of 461 copper IUDs representing four standard models were screened by means of optical microscopy. Especially typical samples were studied at higher magnifications under the scanning electron microscope. The obtained data were considered in terms of statistics. RESULTS: It was possible to demonstrate a preferential corrosive activity in the lower part of the IUD without significant variations between the models. It was also possible to precise the steps of the process, to describe its most characteristic aspects and to study the eventual effect of severe calcareous deposition on corroded copper. DISCUSSION AND CONCLUSIONS: Intrauterine copper corrosion is a normal process which occurs preferentially in the cervical portion of an IUD and can lead to the total metal loss. Both its initiation and evolution are submitted to strong individual variations. Thick and compact vaterite deposits may thwart copper erosion in case of drastic and rapid deposition.

Copper↗

PubMed1977

The effect of acid etching on enamel, dentin, and the inner surface of the resin restoration: a scanning electron microscopic investigation.

Buccal cavities were prepared in vivo on 22 contralateral tooth pairs. The cavities and the surrounding enamel were either etched or cleaned with a surface-active solution (the control). The cavities were filled with Concise Enamel Bond and composite or left unrestored. The teeth were extracted immediately after treatment. Treated surfaces or the inner surface of the restorations were studied in the scanning electron microscope (SEM). An "in-pair" evaluation of the results of 320 photographs was done. The etched axial wall had a smooth surface with widened and patent dentinal tubule apertures. The corresponding inner resin surfaces were irregular, sporadically showing tags of varying length corresponding to the dentinal tubules and alternating with pits of varying size. Etching for 15 seconds or two minutes gave no apparent difference in appearance of enamel, dentin, and inner surface of the restoration.

Acid Etching, Dental↗

PubMed2002

Scanning electron microscopic observation of microvasculature in periodontium.

In this study, vascular resin cast models in the periodontium of beagle dogs were prepared and three-dimensional observation of the relationship between the gingiva and periodontal ligament (PDL) vascular network was performed. After the perfusion of Ringer's solution and fixative, synthetic resin was injected from the inferior alveolar arteries. Soft tissue was digested by proteinase solution and specimens were examined under scanning electron microscope (SEM). The gingival vascular network (GVN) in the region facing the teeth consisted of sulcular and junctional epithelium. The vascular network of the sulcular epithelium (SE) had a renal glomerulus-like form and the junctional epithelium (JE) consisted of squamous mesh. The gingival sulcular fluid exudated from the vascular network directly beneath the JE, and leukocytes permeated from the vascular network beneath the epithelium. Thus, we considered that the GVN performs an important function in the protection against the inflammation. Periodontal ligament had a polygonal mesh vascular network that was anastomosed to the venous plexus of alveolar bone through Volkmann's canals (VC). When occlusal force was applied, the blood in the periodontal vessels flowed out through VC into the bone marrow, and when the force was removed, it flowed backward into the PDL. This blood transfer acted as an absorber against occlusal force. Our findings suggest that the blood vessels of the gingiva perform an important function in defending against inflammation, while the blood vessels of the PDL play a key role in absorbing occlusal force.

Animals↗

PubMed2003

[Scanning electron microscope observation of morphological influence P-aminobenzoic acid (PABA) on Porphyromonas gingivalis].

OBJECTIVE: In order to investigate the effect of PABA produced by Streptococcus sanguis on microecological balance of subgingival plaque, different concentrations of PABA were applied to see if it can influence the form and adherence of P. gingivalis. METHODS: After adding different concentrations of PABA into 1/2 concentration of BHI media, an anaerobic technique was used to culture P. gingivalis. P. gingivalis grew in the medium was observed by a scanning electron microscope. RESULTS: Excessively high or low PABA concentration could influence the form and adherence of P. gingivalis. CONCLUSION: PABA produced by Streptococcus sanguis can affect the form and adherence of P. gingivalis. It indicates that Streptococcus sanguis plays regulative effect on the microecological balance of subgingival plaques.

4-Aminobenzoic Acid↗

PubMed1991

NG-monomethyl-L-arginine increases platelet deposition on damaged endothelium in vivo. A scanning electron microscopic study.

There is increasing evidence that nitric oxide (NO) synthetized in vascular endothelium and in platelets by NO synthase influences vascular tone, down regulates platelet function and platelet-vessel wall interaction both in vitro and in vivo. We investigated the effect of a NO synthase inhibitor, NG-mono-methyl-L-arginine (L-NMMA, 100 mg/kg iv) on platelet-endothelial cell interaction in rabbit arteries ex vivo using scanning electron microscope (SEM). The effect of L-NMMA was examined on intact endothelium and on that damaged by arterial constriction. The infusion of L-NMMA increased systemic blood pressure and decreased carotid blood flow, however, it did not change the appearance of an intact endothelium and did not result in platelet activation on intact endothelial cells. In contrast, SEM of endothelial areas damaged by constriction showed extensive platelet adhesion and aggregation on subendothelium. These morphological changes were not detected in control animals with intact or damaged by arterial constriction endothelium. These results show that under physiological conditions, the inhibition of NO synthase alone does not result in platelet activation in vivo. However, when combined with endothelial injury it may lead to platelet activation and thrombosis.

Amino Acid Oxidoreductases↗

PubMed1975

[Blood microfiltration. Scanning electron microscopic study of the aggregates retained by a transfusion filter made of polyurethane foam].

Preliminary studies of the transfusion filter Bentley PF 127, a polyfilter type with a graded serie of diameters of microfenestration are reported. Dog blood has been used in all instances of the trial phase. Variations of the hematological factors as well as biochemical disparities have been examined and all deposits were assessed by means of scanning electron microscope. Amounts of deposits increased with the blood age. As far as banked dog blood develops less microaggregates during storage than human blood, the SEM pictures reported are a plea for banked blood microfiltration in any transfusion to human beings. The deposits which were trapped in the polyurethane foam, had previously passed through a screen filter with pore size slightly wider than the standard one (250 microns instead of 170 microns). Unfortunately the possibility of thrombus formation is serious as far as banked blood is rather fragile, and due to a slow flow rate, the time of blood contact with the filter is enough to allow thrombus development. However, the amounts of clots greatly increased with the age of the blood. The importance of filtration by adsorption was not very visible. The future of such a depth filter is questionable: should we prefer a transfusion screen filter with small pore size, the efficiently of which is determined by its pore size, and which traps the microaggregates by mechanical retention, or a depth filter which is supposed to retain the microaggregates regard less of the size but which could be very easily thrombus invaded and does not allow a suffisant blood flow rate for patients needing large amounts of blood in period of initial resuscitation? The debate is open but we should recognize that a screen filter with small pore size is widely used in the hospitals.

Animals↗

PubMed1991

Scanning electron microscopic study of subchondral bone tissues in osteoarthritic femoral head.

During total hip replacement for 12 cases of advanced osteoarthritis of the hip joint in aged women, three types of diseased or abnormal articular cartilage with different degrees of severity (white articular cartilage, white and hyperplastic articular cartilage, and yellowish articular cartilage) and ivory bone were obtained together with their subchondral bone tissues. These specimens were processed and studied under scanning electron microscope and were compared with sex- and age-matched non-osteoarthritic femoral head articular cartilage specimens. The following findings were observed: 1. In non-osteoarthritic femoral head, the subchondral bone plate was quite thin. The bone plate connected on its deep surface with the lattice-work of trabeculae of the epiphyseal region. The trabeculae were fine and smooth and some revealed round or spindle-shaped callus resulted from microfracture. 2. In osteoarthritic femoral heads, with increased the severity of the articular lesion, the articular cartilage gradually became thinned out and eventually lost. The subchondral bone plate was markedly thickened. The epiphyseal trabeculae were also thickened and turned rough so that the lattice-work pattern gradually disappeared. The thickened trabeculae finally fused into a large piece of dense bone tissue. No microfracture was detected. These changes were attributable to the increased stress imposed on the subchondral bone tissues as a result of defective articular cartilage. Consequently, the changes on the part of the subchondral bone tissues of the osteoarthritic femoral heads were the sequent, rather than the cause, of the articular lesions.

Cartilage, Articular↗

PubMed1993

Fluoride toxicity: a biochemical and scanning electron microscopic study of enamel surface of rabbit teeth.

The present study has been carried out to investigate the effect of fluoride toxicity on the morphology as well as inorganic chemical constituents of rabbit teeth. Rabbits were administered sodium fluoride at a dose of 10 mg NaF/kg body weight every 24 h for 18 and 23 months. The incisor and molar teeth (whole tooth) were investigated for fluoride, calcium and phosphorus content in 18- and 23-month treated animals. The enamel surfaces of incisor teeth of 23-month treated animals were examined under scanning electron microscope. A significant increase in fluoride levels and significant decrease in calcium content was found following fluoride administration for 18 and 23 months as compared to control. Ca/P ratio was significantly increased only in 23-month treated animals. The scanning electron micrographs revealed hypoplastic, rough, uneven, pitted and cracked enamel surfaces covered with granular deposits as a result of excessive intake of fluoride. It can be concluded that long term fluoride administration leads to severe structural alterations on the enamel surface, possibly through defective mineralization.

Animals↗