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Results for “scanning electron microscope”

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PubMed2006

Scanning electron microscope and micro-CT evaluation of cranial sutures in health and disease.

Current knowledge of suture biology has been ascertained as a result of morphological studies of normal cranial sutures (and rarely those undergoing craniosynostosis). These were initially undertaken often using histological investigations, or more recently using CT scans, as investigative tools, but have often used animal models. However, recent technological advances have provided the potential to refine our understanding of the ultrastructure by the use of new advanced scanning technology, which offers the possibility of more detailed resolution. Our aim was to undertake detailed scans of normal, fusing and fused sutures from patients with craniosynosotosis affecting different sutures, to study the detailed structure at different stages of the fusion process using a modern micro-CT scanner and a microanalytical scanning electron microscope. We wished to include in our study all the human sutures because previous studies have mostly been undertaken using the sagittal suture. Ten sutures from seven patients have revealed a complex ultra-structural arrangement. The different patterns of bone ridging seen on the ectocranial and endocranial surfaces of the fused sagittal suture were not repeated on closer inspection of either fused coronal or lambdoid sutures. Elemental analysis confirmed that the amount of calcium increased and the amount of carbon decreased as sampled areas moved away from the suture margin. We conclude that scanning allowed detailed assessment and revealed the complex arrangement of the structure of the human cranial sutures and those undergoing the process of craniosynostosis, with some differences in final structure depending on the affected suture.

Child, Preschool↗

PubMed1979

A scanning electron microscopic study of the effect of various cleansing agents on cavity walls in vitro.

The appearance of prepared cavity walls after treatment with different cavity cleansers and cleaning procedures was studied. Class II and V cavities were prepared on extracted human and monkey teeth and the cavities were exposed to the different agents for 1 min. Where commercial products were used, the manufacturers' directions for use were followed. The cavity walls were examined in the scanning electron microscope and representative photos were taken from dentinal and enamel areas. Only demineralizing solutions producing an etch pattern were able to remove the smeared layer from the cavity walls.

Animals↗

PubMed1982

A new in vivo replica technique for scanning electron microscope study of dental plaque morphology.

For the micro-morphological investigation of soft oral tissues and deposits on the teeth in vivo, the use of an accurate replica technique is essential if the object under study cannot be examined directly. The conventional replica techniques based on resin or elastomer positive dies, have some limitations due to the instability of the sample die in the scanning electron microscope (S.E.M) conditions and artifacts induced at higher magnifications. Therefore, a new replica technique has been developed using a low viscosity impression material that is subsequently copperplated and poured with synthetic plaster. This offers a stable metal positive die suitable for direct examination in the S.E.M. without prior gold evaporation. Higher magnifications (greater than 7500) are easily obtained without the danger of artifacts. Reproduction of details is of a high order, and the reproduction ability depends only on the accuracy of the first impression. This technique offers new possibilities of discerning fine changes in surface detail in longitudinal clinical investigations.

Adult↗

PubMed1992

[Observation of monoclonal antibody E4B7D5 inhibitory effect on leptospiral adherence using scanning electron microscope].

BALB/c mice were immunized intraperitoneally with outer envelopes of serogroup icterohaemorrhagiae lai serovar strain 017 leptospires. Monoclonal antibody (McAb) E4B7D5 against outer envelopes (IgG1, agglutinating titre 1:25,600) was produced by hybridoma technique. Passive immunoprotection experiments have demonstrated the immunoprotection of McAb E4B7D5 against strain 017 leptospires. Effect of McAb E4B7D5 on leptospiral adherence to the surface of normal human pulmonary embryonic fibroblasts was observed by using scanning electron microscope. The results indicated that the leptospiral adherence noted in various agglutinating titre McAb E4B7D5 groups was less frequent than that in the three control groups. It was concluded that the inhibitory effect of McAb E4B7D5 on leptospiral adherence may play a role in the immunoprotection.

Animals↗

PubMed1999

Favorable scanning electron microscopic findings of stapled saphenous vein-carotid artery anastomoses.

BACKGROUND: In the progress toward "off-pump" endoscopic coronary artery surgical procedures, new techniques for coronary artery anastomoses are being developed. One such approach is the use of nonpenetrating titanium clips. We evaluated the quality of anastomoses achieved using this technique in a porcine model of saphenous vein-carotid artery grafting using scanning electron microscopy. METHODS: Bilateral saphenous vein-carotid artery interposition grafts were implanted in 10 "white race" pigs, using the nonpenetrating clips in one side of the neck and conventional hand suturing on the opposite side. One week after operation, the grafts were harvested. RESULTS: All grafts were patent 7 days after operation, and 40 anastomoses underwent scanning electron microscopic study. In all samples, the luminal surfaces of both the carotid artery and vein graft were covered by a continuous layer of endothelial cells up to the anastomosis. Anastomotic sites in all clipped samples and most of the sutured anastomoses were completely endothelialized, and anastomotic clefts were indistinguishable. However, in 25% of sutured specimens, the suture material remained clearly visible inside the lumen of the vessel, and the subendothelial matrix remained exposed, with extensive fibrin, red blood cells, and platelet deposition on its surface. CONCLUSIONS: Because the endothelial coverage consistently appeared to be complete and the subendothelial matrix was not exposed, it is likely that the risk of early anastomotic thrombosis is reduced by using the nonpenetrating titanium clips.

Anastomosis, Surgical↗

PubMed1996

Hypoplasia of cushion ridges in the proximal outflow tract elicits formation of a right ventricle-to-aortic route in retinoic acid-induced complete transposition of the great arteries in the mouse: scanning electron microscopic observations of corrosion cast models.

BACKGROUND: The major morphologic change associated with retinoic acid (RA)-induced complete transposition of the great arteries (TGA), a congenital malformation of the heart, was investigated in a mouse model in which TGA was found in 80% of surviving fetuses. METHODS: Corrosion casts of embryonic hearts with or without prior exposure to retinoic acid were observed under a scanning electron microscope. RESULTS: In control hearts, indentations caused by expanded parietal and septal ridges in the outflow tract established right ventricle-to-left ventral pulmonic and left ventricle-to-right dorsal aortic routes before the aorticopulmonary septum completion. In RA-treated hearts, indentations of proximal regions of the parietal and septal ridges were small in the proximal outflow tract, whereas those in the distal regions developed well. These morphological features in the RA-treated hearts elicited right ventricle-to-right ventral aortic and left ventricle-to-left dorsal pulmonic routes in the TGA morphology. CONCLUSIONS: Hypoplasticity of the proximal regions of parietal and septal ridges in the outflow tract is one of the primary morphological abnormalities of the RA-induced TGA.

Animals↗

PubMed1975

A scanning electron microscope study of human cerebral arteries.

Human cerebral arteries were obtained from autopsy, fixed under pressure, cut open, and tacked onto pieces of cork. For one artery the intima was partly teased away, exposing the media, and treated with a silver nitrate process. For another artery the adventitia was exposed. Both arteries were processed through graded ethanols and coated with gold paladium for the scanning electron microscope. The collagen fibers of the adventitia were approximately 5 mum in diameter and consisted of a bundle of microfilaments, each of which had a diameter of 800-1000 A (1 A = 10(-10) m). The collagen fibers were oriented parallel to the long axis of the artery. The muscle cells of the media had a diameter of 2-5 mum and were arranged circumferentially with a pitch of approximately 20 degrees. The collagen fibers of the media travel perpendicular to the muscle cells, and parallel to the long axis of the artery. The fibrillar components of the elastin in the intima had a diameter of approximately 700-1000 A and were arranged parallel to the long axis of the artery. It was postulated that the fibrillar part of the elastin was the elastic component of the elastin.

Aged↗

PubMed1975

The diameter and number of dentinal tubules in rat, cat, dog and monkey. A comparative scanning electron microscopic study.

The aim of the study was to investigate in commonly used experimental animals the pulpal wall and the dentin with special reference to the number and diameter of the dentinal tubules. The coronal dentin of a total of 26 permanent, intact teeth from rat, cat, dog and monkey was fractured experimentally. The calculations were based on the study of about 150 scanning electron microscope (SEM) photographs of fractured surfaces and of the pulp chamber wall. The number of dentinal tubules per unit area was calculated and the tubule diameter was measured at various distances from the pulp. The tubules were found to be widest at the pulpal wall, where the mean diameter ranged form 1.7 to 2.8 mum, the highest value being found in monkey and the lowest in the incisors of rat. In the middle part of the dentin the mean diameter varied from 1.0 to 1.3 mum and at the periphery it was 0.6 to 0.9 mum. The largest number of tubules per unit area was found immediately incisal of the pulp horn and the smallest number cervically, near the enamel. At the pulpal wall the mean number of the tubules ranged from 50,000 to 90,000/mm2, in the middle of the dentin it was between 37,000 and 50,000/mm2 and at the periphery it was between 10,000 and 25,000/mm2. In all species examined the dentinal tubules showed a straight course, except in incisors of rat, where local irregularities were seen. A comparison was also made between the species studied and homo with respect to the number and width of the dentinal tubules.

Animals↗

PubMed1989

A scanning electron microscope study of human pulp fibroblasts in culture.

Human pulp tissue was obtained from the first lower right molar of a 24 year old male patient during oral surgery. The tooth was healthy with no evidence of carious lesions. 6 cultures were initiated by the explant method. The cells were isolated and carried through 8 passages. Samples from different passages were fixed, dehydrated, and prepared for scanning electron microscopic observations. Some cells had a smooth surface, while others showed microvillous projections from their surface. Both cell types were seen in the same culture. However, in the third passage all the cells were of the smooth surface type. The cells were interconnected by a system of fibrils that were related to their surface. These fibrils also appeared to anchor the cells to the surface of the coverslips on which they were growing. This study showed that more than one cell type apparently existed in human pulp fibroblasts culture. Whether these cell types have different functional properties, or whether they are different developmental stages of the same cell type in culture, remain to be determined.

Adult↗

PubMed1993

Asbestos fiber type in malignant mesothelioma: an analytical scanning electron microscopic study of 94 cases.

Although the association between asbestos exposure and malignant mesothelioma is indisputable, controversy continues regarding the relative contribution of the various types of asbestos fibers to the development of mesothelioma. We examined the types of asbestos fibers recovered from lung parenchyma in more than 90 cases of malignant mesothelioma from the United States, using an analytical scanning electron microscope. Almost half of the patients were former asbestos insulators or shipyard workers. The fibers were recovered from lung tissues obtained at autopsy or surgical resection by means of a sodium hypochlorite digestion procedure. Amosite asbestos was identified in 81% of the cases and accounted for 58% of all fibers 5 microns or greater in length. Tremolite/actinolite/anthophyllite were identified in 55% of the cases and accounted for 10% of all fiber types. Chrysotile was identified in 21% of the cases and accounted for 3% of fibers exceeding 5 microns in length. Crocidolite was found in 16% of the cases and accounted for 3% of fibers exceeding 5 microns in length. Nonasbestos mineral fibers (commonly found in the lungs of the general population) were observed in 71% of the cases and accounted for 25% of all fibers 5 microns or greater in length. The findings in this study are at odds with the assertion that crocidolite asbestos is responsible for most mesotheliomas in the United States.

Adult↗

PubMed2004

Opisthorchiasis-associated biliary stones: light and scanning electron microscopic study.

AIM: Biliary stones are frequently encountered in areas endemic for opisthorchiasis in Thailand. The present study was to describe the prevalence and pathogenesis of these stones. METHODS: Gallstones and/or common bile duct stones and bile specimens from 113 consecutive cholecystectomies were included. Bile samples, including sludge and/or microcalculi, were examined for Opisthorchis viverrini eggs, calcium and bilirubin. The stones were also processed for scanning electron microscopic (SEM) study. RESULTS: Of the 113 cases, 82 had pigment stones, while one had cholesterol stones. The other 30 cases had no stones. Most of the stone cases (76%, 63/83) had multiple stones, while the remainder had a single stone. Stones were more frequently observed in females. Bile examination was positive for O. viverrini eggs in 50% of the cases studied. Aggregates of calcium bilirubinate precipitates were observed in all cases with sludge. Deposition of calcium bilirubinate on the eggshell was visualized by special staining. A SEM study demonstrated the presence of the parasite eggs in the stones. Numerous crystals, morphologically consistent with calcium derivatives and cholesterol precipitates, were seen. CONCLUSION: Northeast Thailand has a high prevalence of pigment stones, as observed at the cholecystectomy, and liver fluke infestation seems involved in the pathogenesis of stone formation.

Adolescent↗

PubMed1992

Analysis of primary bone formation in porous alumina: a fluorescence and scanning electron microscopic study of marrow cell induced osteogenesis.

Porous alumina ceramics alone and combined with rat marrow cells were implanted subcutaneously in the back of syngeneic Fischer rats. Fluorochrome-labeling was performed post operatively and the ceramics were harvested 6 and 8 weeks after implantation. Undecalcified sections of the implants were observed under fluorescence microscopy and the de novo bone-ceramic interfacial areas were analyzed by a scanning electron microscope equipped with an electron probe microanalyzer. Alumina ceramics alone did not show any bone formation, while all marrow cell loaded ceramics showed new bone formation 6 and 8 weeks after implantation. Bone formation was first observed in the center of the pores and proceeded in a centrifugal direction, leading to contact with the ceramic. These results suggest that bone marrow cells have inherent osteogenic capacity and in the pore region of alumina ceramics progression of the osteogenesis causes the dissipation of intervening fibrous tissue between the de novo bone and alumina ceramic surface.

Aluminum Oxide↗

PubMed1992

Computer-designed inlays after 5 years in situ: clinical performance and scanning electron microscopic evaluation.

Eight mesio-occlusodistal adhesive inlays, fabricated from ceramic blocks using a computer-aided design/machining method, were reexamined after 5 years of clinical service. The inlays wre evaluated according to modified US Public Health Service criteria. The results indicated excellent clinical performance, with eight Alfa ratings for wear, recurrent caries, and color match, and five Alfa and three Bravo for marginal discoloration and marginal integrity. Under scanning electron microscope, 81.0% of the tooth-cement interfaces and 84.1% of the cement-inlay interfaces were rated continuous at the occlusal margin. Axially, 73.6% of the tooth-cement interfaces and 87.0% of the cement-inlay interfaces were rated continuous. Although this long-term investigation revealed good clinical performance of the inlays, improvements in the ceramic structure and its properties, the cavosurface design, and the luting composite resin were recently introduced to further optimize quality.

Ceramics↗

PubMed1987

Vascular corrosion casts of the dog testis after experimental microvascular surgical orchiopexy. A scanning electron microscope study.

Five mongrel dogs underwent microvascular surgical orchiopexy by anastomosing the testicular artery and vein with the respective caudal epigastric vessels. In order to assess the effect of a 40 to 50-min period of warm ischaemia (the time required to make the anastomosis) on the testicular blood vasculature, plastic corrosion casts were made of the operated testes and compared with non-operated control specimens. The resulting blood vessel casts were inspected in the scanning electron microscope. One case of testicular atrophy developed, caused by a postoperative wound abscess. Comparing operated with non-operated testes, no differences in vascularisation, pattern or density of arterial supply, capillary network and venous drainage were seen. These findings are in agreement with data from the literature concerning histological, hormonal and clinical results.

Anastomosis, Surgical↗

PubMed1982

Scanning electron microscope studies on rabbit renal glomerulus, with special reference to "podocytic membrane" of Elias and to pored domes on capillary endothelium.

In their transmission electron microscope (TEM) study of the rabbit kidney, Elias et al. (1964, 1966) reported an occurrence of "podocytic membranes" which were attenuated parts of the body of the podocytes covering the processes and pedicels of podocytes and forming closed spaces, "subpodocytic lacunae" (Fig. 1, 2). In this scanning electron microscope (SEM) study, we demonstrate the three-dimensional structure of rabbit podocytes which largely confirms the Elias' diagram. However, the "podocytic membranes" are not as in Elias' view, attenuated portions of the body of the podocytes, but corresponds to their primary processes which are flattened into plates in this species. The "podocytic membranes" do not represent a second filtration barrier for the primary urine, which Elias proposed. On the glomerular endothelium, we found domed microprojections consisting of a pored cytoplasmic sheet not only in the attenuated portions of the endothelium or areolae fenestratae, but also in the nuclear portion of the endothelial cells. This hitherto unknown distribution of pored cytoplasm necessitates revision of the previous view which has interpreted the significance of the endothelial pores only from the aspect of substance transport through the capillary wall.

Animals↗

PubMed1986

Permanent noise-induced damage to stereocilia: a scanning electron microscopic study of the lizard's cochlea.

Alligator lizards were exposed to broadband noise ranging in intensity from 106 to 132 dB SPL for two hours and permitted to recover from 19 to 62 days. Hearing loss was assessed by comparing the auditory nerve component of the cochlear potential recorded at the end of the recovery period with that recorded before the noise exposure. The stereocilia in these ears were examined with a scanning electron microscope. These sensory hairs showed pathological changes similar to those described in mammalian cochleas with noise-induced damage. In decreasing order of severity the damage included completely missing auditory papillas, missing hair cells, missing hairs, hairs fallen over, and hairs that were only moderately splayed apart compared with their normal appearance. Long lasting hearing loss seems to be associated with all of these sensory hair pathologies.

Animals↗

PubMed1992

[A scanning electron microscopic study on experimental ischemic lesions in dogs].

Occlusion of minute vessels in the bowel wall is thought to be a cause of ischemic lesions. This study was performed to clarify the pathohistology and the morphology of these various lesions. Microbarium suspension was injected into the mesenteric vessels of twenty four dogs and the ischemic lesions were produced experimentally. The degree of the bowel damage was parallel to the amount of injected microbarium suspension. The resected specimen of the various stages of the disease was studied histologically and morphologically by a scanning electron microscopy. With the small amount of barium suspension the lesions were confined to the mucosal layers. The epithelial cells regenerated regularly and the villi normalized rather quickly, and these lesions healed within one to two weeks (transient form). With the large amount of barium suspension the lesions involved both submucosal and muscular layers. The epithelial cells regenerated irregularly and the villi rearranged to abnormal forms. These lesions healed in two to four weeks leaving the stenosis due to scar formation (stricturing form). This study suggests that scanning electron microscopic investigation can be used to assess the details of morphological changes of ischemic mucosa, special reference to the degeneration and regeneration process of epithelium of the villi.

Animals↗

PubMed1995

Scanning electron microscope observation on tegumental damage of 21-d-old Schistosoma japonicum induced by praziquantel.

AIM: To study the effect of praziquantel (Pra) on the tegument of 21-d-old schistosomula, mice infected with Schistosoma japonicum cercariae for 21 d were treated ig with Pra at a single dose. METHOD: Groups of mice were killed at different intervals within 48 h, and the worms were collected by perfusion for scanning electron microscopic observation. RESULTS: When the dose used was 300 mg.kg(-1), the worms showed mild or moderate swelling, fusion or even erosion and collapsed of the tegumental ridges, which was characterized by swelling of the discoid sensory structures. At higher dose of 500 mg.kg(-1), similar alterations in the worm surface were seen, but more extensive and serious. When Pra 500 mg.kg(-1) was given daily for 3 d, severe swelling, erosion and peeling of the tegument accompanied by the attachment of the host leukocytes on the damaged surface were seen. CONCLUSION: Pra exhibited a direct killing effect on 21-d-old schistosomula.

Animals↗