SEARCH · PubMed Health

Results for “scanning electron microscope”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources

PubMed1993

[Trabecular arch structure of the upper end of femur and its biomechanical significance in hip fractures: a scanning electron microscopic study].

Scanning electron microscopic study was carried out in cancellous bone tissues of the femoral heads of 19 specimens. The reticular cancellous bone tissues comprised columns and flakes of trabeculae. The arch structure of the cancellous bone in the femoral head assumed round or roundish configuration, the arch structure of the femoral head-neck junction revealed oval outline, while the arch structure of the femoral neck showed narrow oval profile. The fine structure of the trabeculae in the femoral head could be divided into three zones: superficial zone central zone and transitional zone. Under weight-bearing, the central zone suited to sustain the load, while the superficial zone could produce elastic deformation lest fracture should ensue. These structural characteristics endowed the femoral head cancellous bone tissues the capability to bear weight and to absorb the impulsive load. The arch structure of the femoral head-neck junction and the femoral neck facilitates weight-bearing under physiological condition. However, external violence in the form of either adduction or abduction force, would act in a horizontal direction on the long axis of the oval and narrow oval arches. Under such circumstances, the arch structures would lose their mechanical advantage, and thus subcapital or transcervical fracture of femur might take place in aged people suffering from osteoporosis.

Adult↗

PubMed1995

Extrusion of root-filled incisors in beagles--a light microscope and scanning electron microscope investigation.

The response of the periodontal ligament to orthodontic extrusion of the incisor of a beagle was examined with light microscope and scanning electron microscope techniques. The ligament morphology was slightly altered by the procedure but was essentially normal. Teeth that were extruded and retained for 12 weeks exhibited partial relapse. Where a full thickness mucogingival flap was raised and immediately replaced in lieu of retention, continued extrusion was observed. Root resorption was observed at the interproximal region of the cervical third in three out of five specimens. The resorption had been repaired with cellular cementum.

Animals↗

PubMed1982

Correlative light microscopic and scanning electron microscopic study of completely and incompletely orthokeratinized rat oral epithelium.

Using light microscope (LM) and scanning electron microscope (SEM) a study of the surface morphology of rat oral epithelium was undertaken. A good correlation was found between the LM and SEM findings in the demonstration of the characteristic differences in surface structure between completely and incompletely orthokeratinized areas of the rat oral epithelium. Completely keratinized epithelium (hard palate and attached gingiva) shows a surface layer of orderly arranged, closely approximated and overlapping cells. The individual cell surface shows a honeycomb pattern of interconnecting ridges surrounding depressions or micropits. Incompletely keratinized epithelium (buccal mucosa, alveolar sulci, gingival crest and interpapillary area of the dorsum of the tongue) shows a very uneven, corrugated surface layer. There is considerable loss of cell cohesion with the formation of wide intercellular clefts. The individual cell surface is characterized by microplications of irregular size and arrangement. The findings of the present investigation are discussed in the light of an idea previously put forward by the authors that a correlation exists between surface morphology of the keratinized rat oral mucosa and colonization and penetration of Candida organisms in experimental candidosis.

Animals↗

PubMed1988

Light microscopical and scanning electron microscopical examinations of deposits on disposable constant wear lenses.

An inexpensive, disposable soft contact lens for extended wear (DanaLens) has been developed. The lens is polymerized moulded in the wet state from hydroxyethyl methylacrylate and hydroxyethyl acrylate. Twenty-two pairs of the lens have in an open study been worn permanently from 1 to 43 days. Light microscopical and scanning electron microscopical examinations of the used lenses showed: superficial deposits on the front surfaces of the lenses of a mucous-like, easily removable material. Neither bacteria nor fungi were demonstrated.

Adolescent↗

PubMed1979

[Light microscope and scanning electron microscope findings in acute keratoconus (author's transl)].

An acute keratoconus was examined for the first time using a scanning electron microscope. The alterations in the epithelium of the cornea consisted of a reduction in microvilli and microplicae structures, disruption of the intercellular spaces with raised protrusions of epithelial cells in the region of the peak of the keratoconus or even of the complete disappearance of all regular surface structures. In the stroma distinct irregularities in the lamellae, sometimes even the formation of cavities in the region of the cornea peak, could be seen. These findings correlate well with the light microscope pictures and with the published transmission electron microscopic results.

Acute Disease↗

PubMed1977

The epithelium in healing experimental standard lesions in the gastric mucosa of the rat. A light microscopical and scanning electron microscopical study.

In a series of experiments in rats, the movement of the advancing sheet of epithelial cells streaming from a border region into the woind bed of standardized defects in the glandular mucosa of the stomach was studied using the light microscope and the scanning electron microscope (SEM). A very high synthetic activity of mucus in gastric lining cells of the border region (with a typical shift in its reaction product towards a more acidly reacting product showing metachromasia with toluidine blue) was observed histochemically, together with a loss of characteristic features of glandular cells in the border region with an increase in mitotic activity. The SEM images enabled a detailed analysis of the advancing epithelial front in its relation to the border regions. Considerable local differences were noted in the moving pattern of the migrating epithelium, possibly in relation with the nature of the base on which it has to move. The lesion of 3 mm diameter appeared to close usually after 10 days; in some instances, however, small epithelial defects were later found which could easily be traced with the SEM.

Animals↗

PubMed1986

Collagenous network in cartilage of human femoral condyles. A light microscopic and scanning electron microscopic study.

To determine the spatial arrangement of collagen fibrils in articular cartilage of the human femoral head, three healthy femoral heads, obtained at necropsy, were examined by light microscopy and scanning electron microscopy. Light microscopic observations revealed no collagen fibril organization. Scanning electron microscopic observations showed a fine fibrillar texture throughout the articular cartilage. At the articular surface, smooth and fibrillated areas were detectable. Underneath the articular surface, the collagen network in the superficial zone showed a tighter appearance when compared with the homogeneous collagen network of the matrix in the deeper zones. The calcified cartilage zone was well demarcated from the uncalcified cartilage. The arcade model of Benninghoff [Z. Zellforsch. Mikrosk. Anat. 2: 783-862 (1925)] could not be confirmed. It was concluded that the organization of collagen fibrils in hyaline cartilage shows a three-dimensional network of randomly oriented fibrils.

Adult↗

PubMed1977

[Light microscopic and scanning electron microscopic observations on phagocytosis of Plasmodium berghei infected erythrocytes by mouse macrophages [author's transl)].

Peritoneal macrophages from mice were cultured in Leighton tubes for 2 hours. Thereafter suspensions of washed red blood corpuscles originating from Plasmodium berghei-infected mice were offered to the cultured cells for phagocytosis. After 15 minutes of incubation 13,5% of the macrophages showed phagocytized parasites if the peritoneal cells came from malariaimmune mice. Cells from normal mice or from infected mice had lower rates (4,8/9,1%). After an incubation of 3 hours about 50% of the cells showed phagocytosis in all three groups. The system used allowed to estimate the halftimes for intracellular elimination of the parasites. The values are 27 minutes for cells from immune animals, 57 minutes for cells from normal animals, and 66 minutes for cells from infected animals. Details of the process of phatocytosis were recorded by scanning electron microscopic pictures.

Animals↗

PubMed1977

Vascularization of the pars intermedia of the hypophysis in the toad, , Bufo bufo (L.) (Amphibia, Anura). A comparative light microscopical and scanning electron microscopical study. II.

The vascularization of the pars intermedia of the hypophysis of the toad, Bufo bufo (L.) was studied by injection of a mixture of India-ink and gelatine into the circulatory system of the head via the arteria carotis communis. Further methyl-methacrylate corrosion casts of brains were made and the hypophysial region of the corrosion casts was examined with the scanning electron microscope. The results showed that the vascularization of the pars intermedia of the toad hypophysis consists of a single-layered vascular network, which is located on the ventral surface of the pars intermedia. The network is formed by capillaries, which primarily run caudally in a fan-like manner and which show only a few cross-connections. In the rostral region of the pars intermedia this network lies rather superficially, while in the caudal region it slightly penetrates the parenchyma. The vascular network originates from vessels of the neural stalk and from wide capillaries of the rostro-ventral region of the neurointermediate junction. The venous drainage of the pars intermedia is exerted by veins, which leave the caudal region and drain into the veins leaving the venous pole of the pars distalis. The flat, wide meshed vascular net on the ventral side of the pars intermedia, demonstrated in this study, fits into the concept that the pars intermedia of the anuran hypophysis is under the control of nerve fibers coming from the hypothalamus.

Animals↗

PubMed1977

Vascularization of the pars distalis of the hypophysis in the toad, Bufo bufo (L.) (Amphibia, Anura). A comparative light microscopical and scanning electron microscopical study. I.

The vascularization of the pars distalis of the hypophysis of the toad, Bufo bufo (L.), was studied by the traditional method of injecting a mixture of India-ink and gelatine into the circulatory system of the head via the arteria coratis communis. Further, methyl-methacrylate corrosion casts of the brains were made; the hypothalamo-adenohypophysial region of these corrosion casts was studied with the scanning electron microscope. The results showed that the portal vessels which arise from the median eminence do not supply distinct areas in the pars distalis as is supposed by the point-to-point-hypothesis. The portal vessels enter the ventro-median region of the pars distalis and branch off into a three-dimensional network of the secondary capillary plexus of the pars distalis. The plexus is made up mostly by four- to six-sided meshes. This angioarchitecture guarantees an optimal supply of the glandular cells of the pars distalis with nutritional factors and releasing hormones, on the one hand, and facilitates the removal of the hormones which are released by these cells, on the other hand. The venous drainage of the pars distalis is exerted mainly by two large veins, which bilaterally leave the dorso-lateral region (venous pole) of the pars distalis and by a few small veins, which drain into the wide, sinus-like vessel, which curves around the dorso-caudal region of the pars distalis and joins bilaterally the vena hypophysea transversa.

Animals↗

PubMed1983

A light microscopic and scanning electron microscopic study of intraventricular macrophages in the brains of aged mice.

Intraventricular macrophages in the aged mouse brain (25-31 months) are found mainly on the surface of the choroid plexus. About half the population are flattened cells similar to those described by a number of authors in adult animals. The remainder are partially or completely distended due to the presence of varying amounts of lipid, either in the form of droplets or of foamy masses. These variations in shape are visible in the scanning electron microscope, as well as in semithin sections. The source of the lipid is unclear. It may result from passage of lipid into the cerebrospinal fluid from the ependyma, because many ependymal cells contain large lipid droplets. Alternatively, the lipid may be the result of phagocytosis of degeneration products of epithelial cells of the choroid plexus, either of complete cells, or of parts of cells extruded into the cerebrospinal fluid.

Aging↗

PubMed2002

Carbon fibres and plasma-preserved tendon allografts for gap repair of flexor tendon in bovines: gross, microscopic and scanning electron microscopic observations.

The efficacy of carbon fibres and plasma-preserved tendon allografts for gap repair in the superficial digital flexor tendon in the mid-metatarsal region was evaluated in 12 crossbred calves. Experimental tenectomies were performed, followed by implantation of carbon fibres in group I (12 legs) and plasma-preserved tendon allografts in group II (12 legs). Gross observations in group I showed filling of the defect with granulation tissue with more vascularity on day 7, which was less prominent at day 14. On day 30, the neotendon formed was slightly thicker and comparable to normal tendon in appearance and texture. On day 90, it exhibited all the characteristics of a fully developed tendon. Whereas, in group II increased vascularity at the site and encapsulation of the graft with connective tissue in early periods was observed. The gap between graft and host was filled with fibrous connective tissue. Peritendinous adhesions were maximum on day 7 which were gradually reduced in both groups. Microscopically, an acute inflammatory reaction in the periphery of carbon fibres was observed on day 7. Immature fibroblasts were arranged in a haphazard pattern at this stage. By day 14, numerous newly formed capillaries and comparatively more mature fibroblasts were present in between and around the carbon fibres which were aligning parallel to the longitudinal axis of the tendon. By day 30 the healing tissue exhibited longitudinal orientation of collagen fibres and was at a more advance stage of maturation. By day 90, the neotendon formed simulated the picture of normal tendon. In the grafted tendon group, there was normal healing tissue at the functional sites between host and grafted tendon. The fibroblastic activity appeared to be both extrinsic and intrinsic in origin. The connective tissue had invaded the graft to a variable distance and there was resorption of graft which was replaced by newly formed connective tissue on day 90. Scanning electron microscopic observation revealed formation of neotendon between carbon fibre strands, resulting in thickening of the implant. In later stages parallel collagen fibres resembling normal tendon were observed in both groups.

Animals↗

PubMed2003

Acellular and glutaraldehyde-preserved tendon allografts for reconstruction of superficial digital flexor tendon in bovines: Part II--Gross, microscopic and scanning electron microscopic observations.

Sixteen tenorrhaphies were performed at mid-metatarsal region in eight buffalo calves. A 2-cm long gap was created in the superficial digital flexor (SDF) tendon in all animals. The gap was immediately repaired with acellular grafts in animals of group I, 1% glutaraldehyde-preserved tendon allografts in group II, and in group III the defect was repaired with autografts (control group). The contralateral limb in each animal was operated after an interval of 60 days and the animals underwent the same procedure according to the designed groups. Gross observation revealed filling of host tendon-graft junction with fibrous connective tissue. Increased vascularity was seen in group I when compared with group II and III. Graft was resorbed in animals of group I and III, whereas partial absorption of graft was seen in group II. Histological observations on day 30 revealed restoration of cellularity in acellular graft and fragmentation and resorption of glutaraldehyde-preserved graft. Graft was replaced by newly formed fibrous connective tissue. Tissue reaction around polygalactin suture consisted of plasma cells, lymphocytes and macrophages. On day 90, most of the acellular graft was replaced by newly formed fibrous connective tissue. In group II the majority of graft portion remained at the site and was in a state of resorption. In the control group it was difficult to distinguish between the host tendon and the graft. Scanning electron microscopical observation showed densely packed neoformed tissue at host tendon-graft junction. Hydrolysis and invasion of connective tissue between polygalactin suture filaments, resorption of graft with cavity formation and dissolution of ground substance were observed.

Animals↗

PubMed1985

Osteoarthritis of the temporomandibular joint: a light microscopic and scanning electron microscopic study of the articular cartilage of the mandibular condyle.

The aim of this study was to investigate the organization of collagen fibrils and the histopathologic alterations as well as the morphologic aspects of osteoarthritic articular cartilage of the human mandibular condyle. Nine osteoarthritic condyles, three obtained at necropsy and the other six during surgery, were examined by light microscopy and scanning electron microscopy. Light microscopic observations revealed features of progressive and regressive remodeling and the presence of clefts. Scanning electron microscopic observations showed the presence of thick, coiled fibrils at the joint surface and numerous osmiophilic lipid globules scattered between the collagen fibrils. The collagen fibrils were disordered. It was concluded that collagen fiber network disintegration and fatty degeneration comprise the osteoarthritic changes of the articular cartilage of the human mandibular condyle.

Adult↗

PubMed1994

Calcification of porcine bioprosthesis implanted into human heart: high resolution scanning electron microscopic and scanning tunneling microscopic investigation.

High-resolution scanning electron microscopy (HR-SEM) combined with scanning tunneling microscopy (STM) was used to investigate the calcification mechanism occurring in the porcine bioprostheses implanted into the human heart. Eleven explanted porcine heart valves obtained during open heat surgery were prepared for HR-SEM and STM observations. HR-SEM examinations of all explanted valves with secondary and backscattered electron imaging revealed abnormal accumulation of calcium in various shapes and sizes on the defective valve surface and in the underlying basement membrane. Calcific deposits were consistently observed within the pinhole defects on the valve surface and in the subsurface structures of the valve tissues along the surface defects. In addition, calcium-containing crystals were often present just underneath the disrupted valve surface. STM examinations also showed that calcific deposits were frequently accumulated in or around the pinhole defects on the valve surface. Thus, STM findings were compatible with HR-SEM observations. In view of the occurrence of calcific deposits in the vicinity of the surface defects on the valve tissue and frequent observation of calcific spots and crystals in the subsurface structures just beneath the defective valve surface, our results prove the hypothesis that alteration of the valve surface is an important factor for calcification occurring in the implanted bioprosthetic heart valves.

Animals↗

PubMed1981

Characterisation of urinary crystals and thin polished sections of urinary calculi by means of an optical microscopic and scanning electron microscopic arrangement.

The use of optical microscopy and scanning electron microscopy combined permits a more far-reaching investigation of a given specimen. The subsequent element distribution analysis (EDAX system) allows the determination of mixed phases, inclusions and single crystals. The instrument combination was successfully tried on urinary crystals and thin sections of urinary calculi. The description of some findings, with the aid of examples, explains the efficiency of the system in the expansion of urinary calculus analysis.

Crystallization↗

PubMed1983

The fragile X: a scanning electron microscope study.

Scanning electron microscopy (SEM) has been used to study the fragile X chromosome. The fragile site appears as an isochromatid gap in the majority of cases, confirming light microscope (LM) observations. SEM has allowed a more precise location of the fragile site to the Xq27 . 3 region.

Chromosome Mapping↗

PubMed1977

Lesions of experimentally induced colibacillosis in neonatal gnotobiotic pigs: a scanning electron microscopic study.

Scanning electron and light microscopy were used in studies of stomach, duodenum, cranial, and caudal portions of the jejunum, ileum, cecum, and spiral colon from 18 gnotobiotic pigs. Five pigs were raised as controls and 13 were exposed at 6 days of age by oral administration of 1.6 X 10(6) colony-forming units of Escherichia coli O138:K81:NM. Infiltration of leukocytes into the mucosa of the stomach seen with the light microscope has not been previously reported. The irregular pattern of the mucosal surface of the stomach formed by the gastric pits and the mucosal extensions on the individual rugae revealed with scanning electron microscopy was different than anticipated. Sections of the ileum from control and infected pigs contained collapsed cells around the extrusion zone at the tips of the villi. These collapsed cells were more numerous in infected pigs and appeared to have sloughed from the area of the extrusion zone resulting in exposure of the lamina propria. Cecum and spinal colon were free of changes. Alterations of the mucosa of the intestinal tract of gnotobiotic pigs infected with E coli as visualized by scanning electron microscopy were considered too inconsistent to be of diagnostic significance.

Animals↗