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Results for “scanning electron microscope”

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PubMed1989

[A scanning electron microscopic study on the arteriovenous anastomoses of rabbit ear using corrosive resin casts].

Arteriovenous anastomoses (AVAs) partake in the regulation of blood flow, and although it has been speculated that AVAs in the rabbit ear play a major role in the regulation of the body temperature, no documented work is available on the structural characteristics of AVAs in the rabbit ear. Accordingly, the purpose of this investigation was to determine the frequency of AVAs and their structural characteristics by using the vascular corrosive resin casts and further examination under a scanning electron microscope (SEM). This method permitted not only the visualization of a three-dimensional view of AVAs, but also depicted a clear differentiation between AVAs and arterioles or venules. Within the vascular architecture of rabbit ear, three distinctive vascular layers could be identified. The frontal and dorsal epithelial vascular layers are distributed underneath the epithelium and formed with nearly all capillaries, and the intermediate vascular layer which is established with main arteries, veins and their branches. The AVAs were observed in all three vascular layers, although various venous valves were concentrated primarily in the intermediate vascular layer. In tabulating the frequency of appearance of AVAs, the mean number was 81.5 per centimeter square. The mean number of AVAs in each of the three vascular layers was 31.1 in the frontal layer, 17.1 in the intermediate layer and 33.1 in dorsal layer, respectively. The vasculature of rabbit ear was further anatomically divided into tip, middle and root portions. The mean number of AVAs in each portion, from the tip to the root was 112.9, 49.4 and 84.4, respectively. Several essential types of AVAs were observed, such as the S-shaped and similar forms which were the predominate type. Others observed were U-shaped, straight, Y-shaped and tri-branching types. Most AVAs within the intermediate vascular layer, consisting of a few small vessels which were mainly capillaries and venules, connected to the anastomosing portion of AVA. The high occurrence and strategic location of AVAs in the rabbit ear strongly suggest that AVAs in the rabbit ear partake in thermal regulation.

Animals↗

PubMedDate not supplied

Scanning electron microscopic study on double and single eyelids in Orientals.

The conventional theory is that Occidentals have a terminal insertion of the levator aponeurosis at the anterior portion, resulting in a double eyelid, whereas in Orientals this fiber is not present, and therefore results in a single eyelid have been anatomically demonstrated. However, there have been more than a few reports indicating that the anatomical difference between a single eyelid and double eyelid in Orientals cannot be explained by this theory. Therefore, in order to verify the direction of the levator aponeurosis in the eyelids of Orientals, we observed Japanese eyelids using a scanning electron microscope (SEM). As a result of three-dimensional, cross-sectional observations using SEM, we were able to confirm the existence of a branch of the levator aponeurosis that runs through the layer of the orbicularis oculi muscle and connects with the levator aponeurosis in the double eyelid, as in the occidental eyelid. This was not seen in the single eyelid. It is thought that this new anatomical finding will become an important fundamental for double eyelid operations in Orientals.

Aged↗

PubMed2000

Efficacy of final irrigation--a scanning electron microscopic evaluation.

The purpose of this in vitro study was to determine the degree of removal of pulpal remnants and smear layer from root canals after final irrigation with three different solutions. During instrumentation the step-back preparation and 1% NaOCl were used. The final 4-min, 30-ml irrigation varied as follows: group I, 10 ml of 1% NaOCl + 10 ml of 10% citric acid + 10 ml of distilled water; group II, 15 ml of 0.5% NaOCl + 15 ml of EDTA-T; and group III, 10 ml of 5% NaOCl + 10 ml of 3% H2O2 + 10 ml of 5% NaOCl. Scanning electron microscopic photomicrographs were evaluated for the mean number of visible open dentinal tubules by three observers. The largest number of visible tubules in the three groups was in the cervical third, followed by the middle and apical thirds. There was no statistically significant difference between groups I and II when third was compared with third; however, groups I and II had significantly more visible dentinal tubules than group III.

Acid Etching, Dental↗

PubMed1999

The removal of the smear layer using the Quantec system. A study using the scanning electron microscope.

AIM: The aim of this study was to determine the ability of the Quantec Series 2000 rotary nickel-titanium endodontic system to remove dentinal debris and smear layer produced during canal preparation. METHODOLOGY: A first group (control) of 12 curved root canals was prepared using conventional manual instruments and the step-back technique. A second group of 12 curved root canals was instrumented using the complete Quantec sequence according to the manufacturer's instructions. In both groups, irrigation was performed using a 3% NaOCl solution. The canal walls were observed under a scanning electron microscope and the coronal, middle and apical thirds of each canal photographed at a magnification of 500. The views were divided into 10 subareas by overlaying a grid, and the absence or presence of a smear layer was rated and scored on three appearances using the scale described by Ciucchi et al. (1989). RESULTS: The scores were higher (i.e. less debris was present) in the middle third (P < 0.0001) and in the apical third (P < 0.0001) of canals prepared with the Quantec system when compared with those prepared with K-files. Nevertheless, in canals prepared with Quantec instruments, the scores were significantly higher in the coronal third compared with the apical third (P < 0.005). CONCLUSIONS: The Quantec rotary system produced cleaner canal walls than conventional manual instrumentation, particularly in the middle and apical thirds. This finding may imply that stresses applied to the cutting regions of Quantec instruments by accumulation and compression of the smear layer are minimized.

Dental High-Speed Technique↗

PubMed1998

Hollow implants retrieved for fracture: a light and scanning electron microscope analysis of 4 cases.

One of the possible complications of implant treatment is the occurrence of an implant fracture. Metal fatigue and biomechanical overload seem to be the most common causes of fractured implants. This study evaluated 4 implants (3 hollow cylinders and 1 hollow screw) which fractured after a mean loading period of 2.8 years. All implants had a 4 mm diameter and had been inserted in a posterior location. In 3 cases parafunctional habits were present. In all cases a vertical resorption of the peri-implant bone was present. The endosseous portion of the implant presented always a very high bone-implant contact percentage. Scanning electron microscopic examination showed that at least one of the implant holes was involved in the fracture line; no porosities or material defects were observed on the fractured surface of the implant. In hollow implants the holes could represent a site of less resistance.

Alveolar Bone Loss↗

PubMed1990

Scanning electron microscopic study of laser-induced morphologic changes of a coated enamel surface.

A low-energy Nd:YAG laser was used to irradiate extracted human teeth coated with a black energy-absorbent laser initiator in a study to determine the extent of the morphologic changes produced in the enamel surface. The laser initiator was applied to a cleaned enamel surface and irradiated at an energy output of 30 mJ or 75 mJ. Both energy levels produced morphologic changes of the surface. There was a sharp line of demarcation between the coated, irradiated area and the surrounding noncoated enamel surface. The scanning electron microscope view at the lower energy level showed that the surface had melted and reformed with numerous small, bubble-like inclusions. The 75 mJ energy level showed individual impact craters with shallow centers and raised edges containing numerous pores and large, bubble-like inclusions. Etching is a dental procedure in which an acid is normally used to remove a thin outer layer of the tooth structure. This is necessary to create a roughened, irregular surface in order to provide mechanical retention for dental restorative materials. The changes produced by the laser in this study suggest a simple, effective, and controlled method of etching the enamel surface of a tooth by altering its surface characteristics.

Humans↗

PubMed1980

[Pili canaliculi (uncombable hair syndrome or spun glass hair syndrome). A scanning electron microscope study of ten new cases (author's transl)].

"Uncombable hair" is the denomination applied to a new abnormality of the hair, being characterized by its arranged in bundles disposed in different directions and which are irreductible on combing. It may have a familial trait and starts at the age of 3 months onwards. It appears in children of both sexes, whose hair becomes dry, tightly curled, shiny, lighter and impossible to comb. There are no accompanying abnormalities in the development. Neither have any biological changes been registered. The clinical and ultrastructural aspects of 10 cases of children affected with "uncombable hair" are presented. At the scanning electron microscope we have observed longitudinally disposed canalicular formations on the cuticular surface of 50 p. 100 of hair taken from each patient. The canal is, in some zones, more excavated than in others, occasionaly has an irregular outline and sometimes is uniformly located nearly along the whole length of the hair. The transversal section shows triangular aspects, kidney-shaped or completely irregular. We agree with Dupré to use the term pili canaliculi for the defect shown by these patients.

Adolescent↗

PubMed1994

Scanning electron microscopic evaluation of different endodontic procedures on dentin morphology of human teeth.

Four manual endodontic instruments, an ultrasonic and an endosonic system were studied with a view to evaluating the morphology of the smear layer and the amount of debris and pulpal residues in the apical third of human extracted straight teeth from 55- to 75-yr-old patients. The manual instruments were K files, Ergoflex files used with the step-back technique, Canal Master with its own technique, and Flex-R with the Roane technique. The ultrasonic system was Suprasson Piezo and the endosonic was Excalibur. Human extracted teeth with straight canals were used and examined under a scanning electron microscope. All manual instrumentations showed a homogeneous compact smear layer and no pulp residues. No statistical differences were observed among the four manual techniques. Ultrasonic technique showed the complete removal of the smear layer, leaving small amounts of pulp debris at the apical third, while the Excalibur showed an almost complete elimination of the smear layer, leaving a homogeneous layer of pulpal residues along the canal.

Aged↗

PubMed1991

Scanning electron microscopic study of the effect of salivary pellicle on enamel erosion.

A bovine tooth model system was used to study the effect of experimental salivary pellicle on enamel erosion. Test blocks with varnish-covered control surfaces in each specimen were immersed into an acidic cola beverage (pH 2.6) for 120 min, either with or without the pellicle which was grown for 7 days by using clarified human saliva. After immersion, the pellicle was removed from some specimens with 10% sodium hypochlorite (20 h at 20 degrees C) and ultrasonic bath (60 s) to study its effect on erosion. All specimens were then studied in the scanning electron microscope. The specimens without pellicle (positive controls) showed gross erosion with prism core dissolution in all study blocks. The specimens with pellicle showed occasionally a film-like integument covering the apparently intact test surfaces with adjacent enamel surfaces slightly eroded. The erosion, however, was not of the same magnitude as in the positive controls. After removing the pellicle, the enamel surfaces showed pitted appearance of the prism heads; the demineralization seemed to attack more the prism sheath areas. Thus, salivary pellicle was found to protect the underlining enamel from erosion in vitro.

Animals↗

PubMed2004

Effects of multigrooved surfaces on osteoblast-like cells in vitro: scanning electron microscopic observation and mRNA expression of osteopontin and osteocalcin.

This study evaluated the behavior of osteoblast-like cells on multigrooved surfaces consisting of a combination of microgrooves and macrogrooves. A polystyrene substrate was fabricated with multigrooves with 90-degree, V-shaped microgrooves with a 2-microm pitch cut on trapezoidal macrogrooves, which had a 50-microm ridge width, a 50-microm wall width, a 50-microm bottom width, and 25-microm depth. Smooth polystyrene substrates were also prepared as controls. Rat bone marrow cells were cultured as osteoblast-like cells on the substrates for morphological evaluation using a scanning electron microscope, and for biochemical evaluation using the quantitative reverse transcriptase-polymerase chain reaction technique for osteopontin and osteocalcin mRNA expression. After 8 days of incubation, the osteoblast-like cells were aligned parallel to the surface grooves on the multigrooved substrates. After 16 days of incubation, a dense mineralized extracellular matrix (ECM) was produced along the multigrooves. The ECM on the multigrooved surface appeared oriented more in the direction of the grooves than on the smooth surface, and trapezoid-shaped macrogrooves of the ECM were cast upside down. Although there were not significant differences, the osteopontin and osteocalcin mRNA expressions of the osteoblast-like cells on the multigrooved surfaces tended to be higher than on smooth surfaces. These results suggest that multigrooves could be used to control the orientation of mineralized ECM as well as of cells, and also to enhance the production of mineralized ECM.

Animals↗

PubMed1984

Fallopian tubal mucosal damage induced experimentally by Escherichia coli in the rabbit. A scanning electron microscopic study.

Pelvic inflammatory disease is the main cause of infertility due to a tubal factor. The importance of Gramnegative bacteria as major infecting organisms in pelvic inflammatory disease has been recently recognized. The predominant facultative pathogen found in tuboperitoneal fluid from women with salpingitis are coliform bacteria. This study describes an animal model for E. coli mediated tubal mucosa damage. E. coli (10(5)-10(9) bacteria 1 ml) was injected into the right Fallopian tube of sixty rabbits; the left tube injected with culture medium, served as a control. The luminal surface of the oviducts was examined by scanning electron microscope at various intervals after the injection. The degree of damage was found to be dose-dependent and maximal seven days after innoculation. The injury comprised of large areas of deciliation, severely shortened cilia, swollen and adherent throughout their entire length and disappearance of microvilli from the secretory cells. A process of regeneration began two weeks after the innoculation and was completed eight weeks later. Fertility studies carried out after completion of regeneration showed no difference in the ratio of corpora lutea/gestational sacs between the treated and control sides of individual pregnant animals. This model sheds light on the pathogenesis of tubal surface injury by E. coli and suggests that the major effects described are mediated through the endotoxin liberated from the cell wall of these bacteria and that, therefore, antibiotic treatment has no effect on the magnitude of injury. Endosalpingeal regeneration correlates well in this animal model with normal fertility suggesting that morphologic integrity of the surface epithelium may be a good criterion in assessing the reproductive capacity of the fallopian tube.

Animals↗

PubMed1986

Changes in the urine and scanning electron microscopically observed appearance of the rat bladder following treatment with tumor promoters.

Urine of rats treated with promoters of urinary bladder carcinogenesis was analyzed during weeks 8 to 24 of administration. The sodium salts of several chemicals, including ascorbic acid, erythorbic acid, acid saccharin and o-phenylphenol increased the urinary pH and sodium ion concentration of the urine. In contrast, treatment with sodium hippurate did not cause elevation of urinary pH although it increased the sodium ion concentration in the urine. Butylated hydroxyanisole, butylated hydroxytoluene (BHT), and ethoxyquin did not affect the urinary pH or any electrolytes except for an increase of phosphorus in the urine of rats given BHT or ethoxyquin. Scanning electron microscopic examination showed that epithelial cells of the urinary bladder of rats given promoters of urinary bladder carcinogenesis had pleomorphic microvilli, short, uniform microvilli, and ropy or leafy microridges on their surfaces. Thus, for the class of promoters including the sodium salts of weak to moderate acids, the elevation of urinary pH and the increase of sodium ion concentration accompany the promoting activity, whereas these changes do not occur following administration of the antioxidant class of bladder tumor promoters.

Animals↗

PubMed1997

Histological basis for indirect videostroboscopic phonosurgery--a scanning electron microscopic study.

Indications for indirect videostroboscopic surgery are well established for small, benign functional lesions of the vocal folds. Epithelial cells of the vocal folds are spindle-shaped and by their long axies run parallel to the free edge of the vocal fold. This occurrence is used clinically by surgeons to obtain an even operative defect when using a cup forceps during single-handed manipulations. Nevertheless, there are still some doubts about single-handed procedures, so that many surgeons prefer the convenience of bimanual manipulation offered by direct (suspension) microlaryngoscopic surgery. The aim of this study was to demonstrate that single-handed manipulation during indirect videostroboscopic surgery permitted obtaining regular edges of an operative defect during laryngeal surgery. A scanning electron microscopic study was conducted on five cadaver larynges following indirect videoscopic excisions at the vocal fold's free edge and ten controls. Results demonstrated a clearly regular edge of the operative defects in cases when a posterior traction surgical procedure was followed. These findings reaffirm the value of indirect videostroboscopic surgery for small, benign functional lesions of the vocal folds.

Adult↗

PubMed1987

Surface changes during the arrest of active enamel carious lesions in vivo. A scanning electron microscope study.

The present study examines early enamel surface alterations taking place when active carious lesions enter an arrested stage. Orthodontic bands with a standardized space for plaque accumulation were used to produce incipient carious lesions on the buccal surface of all four first premolars of four young adolescents. The premolars were to be extracted for orthodontic reasons. After 4 weeks of local cariogenic challenge, all teeth were debanded. In each patient one tooth was extracted at the time of debanding. The remaining premolars were extracted 1, 2, and 3 weeks after re-exposure to the oral environment. No fluoride was added during the entire test period, and the patients were told to maintain usual oral hygiene. Scanning electron microscope examination of the experimental surface areas disclosed a gradual wearing away of the outermost crystals during the 3 weeks of observation. This was associated with a leveling off of surface irregularities and the development of a multitude of scratches. The observed attrition of the porous surface in the lesion area indicates that functional wear and toothbrushing were responsible for the arrestment by disturbance and removal of bacterial deposits.

Bacteria↗

PubMed1999

Scanning electron microscopic study of the interface of glass ionomer cement sealers and conditioned bovine dentin.

This in vitro study characterized the interface of glass ionomer cement root canal sealers and dentin conditioned by common endodontic irrigants. The interface of Ketac-Endo and two experimental glass ionomer cement sealers (KT-308 and ZUT) with bovine dentin--conditioned with either distilled water, 2.6% NaOCl, or 17% EDTA, followed by 2.6% NaOCl--was investigated. Cylinders of each of the sealers were formed on the conditioned dentin surface and allowed to set for 90 min. They were first shear tested to failure to determine their adhesive bond strength. Then three dentin specimens from each group were processed for scanning electron microscopic study. The test-failed surface of the strongest and weakest bonded specimens was examined. A third specimen, of intermediate bond strength, was cross-sectioned and the interface was also examined. Failures in all of the specimens were found to be mainly cohesive in nature. Specimens conditioned with 2.6% NaOCl only revealed the presence of a hybrid layer at the interface composed of dentin and whichever of the sealers were tested.

Animals↗

PubMed1985

Effects of infection with Eimeria tenella upon Salmonella typhimurium infection in the gnotobiotic chicks. Scanning electron microscopic study.

The gnotobiotic chicks infected with Eimeria tenella received an oral inoculation of Salmonella typhimurium 4 or 8 days after E. tenella infection. Chicks were necropsied one day after the salmonella infection. In the experiments 1 and 2, there were two groups; birds infected with S. typhimurium alone and birds infected with a combination of E. tenella and S. typhimurium. The number of S. typhimurium in the cecal contents was significantly greater in the concurrent infections than S. typhimurium infection alone. The S. typhimurium counts in the cecal wall of gnotobiotic chickens killed 5 days after E. tenella infection were significantly greater than those of chickens infected with S. typhimurium alone. In the experiment 3, the scanning electron microscopic study was made on damage of cecal mucosa. There were four groups; uninfected birds as control, birds infected with E. tenella, birds infected with S. typhimurium and birds infected with a combination of E. tenella and S. typhimurium. No damage was observed on the cecal mucosa of both the control and the S. typhimurium infection alone. The concurrent infections caused greater damage on the cecal mucosa than did the E. tenella infection alone.

Animals↗

PubMed2006

Effect of tribendimidine on adult Echinostoma caproni harbored in mice, including scanning electron microscopic observations.

Food-borne trematodiasis is an emerging public health problem with more than 10% of the world's population at risk of infection, yet there are only 2 drugs available for treatment and morbidity control. We assessed the effect of a promising broad-spectrum anthelmintic drug, i.e., tribendimidine, with an experimental focus on adult Echinostoma caproni. Female NMRI mice were infected with 30 E. caproni for 2 wk and then administered single oral doses of tribendimidine ranging between 25 and 500 mg/kg. Three days post-treatment, mice were necropsied, and adult worms were recovered from their intestines. Worm burden reductions were assessed against untreated control mice. In addition, scanning electron microscopic observations were done on adult E. caproni recovered from mice given a single dose of 150 mg/kg tribendimidine intragastrically 2, 4, and 8 hr post-treatment. Worm burden reductions of 100% were achieved at doses of 125 mg/kg and above. Severe damage of the tegument, including extensive peeling, formation of blebs, and structural loss of the definition of collar and tegumentary spines already occurred within 2 hr after drug administration. Our findings call for further investigations using tribendimidine in other trematode-animal models, because this compound shows promising trematocidal activity.

Animals↗

PubMed1988

A study of immunogold-labelled blood group A erythrocytes in the scanning electron microscope.

This report presents binding patterns on A1, A2, A3, Ax and Ae1 erythrocytes of a monoclonal anti-A (A 003) antibody which reacts predominantly with difucosylated A oligosaccharides, visualized with colloidal gold particles in the backscattered electron imaging mode of a scanning electron microscope. A relatively weak labelling was found on most A1 cells, while the labelling in subgroups A2, A3 and especially Ax appeared relatively stronger. Very few Ae1 cells were labelled. The results emphasize the qualitative uniqueness of A1 and suggest that many Ax cells have high proportions of difucosylated A oligosaccharides. Labelling variations were found between different A3 and Ax traits, and in all subgroups between cells and even between different parts of the cells. No immunolabelling differences were found in relation to secretor status.

Antibodies, Monoclonal↗