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At least 1,027 records · Page 57Linked to original sources
PubMedDate not supplied

Subjective vs. objective analysis of the corneal endothelial cells in the rabbit cornea by scanning electron microscopy - a comparison of two different methods of corneal fixation.

OBJECTIVE: To illustrate a method of quantitative scanning electron microscopy (SEM) for the evaluation of the corneal endothelia of small animals by comparing two commonly used fixation methods. ANIMALS STUDIED: Female New Zealand white rabbits, aged 10-12 weeks. PROCEDURES: The corneas were either dissected from the eye and placed in fixative (2% glutaraldehyde in 80 mm cacodylate, pH 7.4) or the whole eyeball immersed in fixative solution and the cornea dissected later. Lower (x 200) and high magnification (x 1,000-5,000) images were inspected for overall appearance. Magnification images (x 500) were used to measure the areas of 100 cells, and cell density (CD) calculated from the average area. RESULTS: Both fixation protocols yielded an intact endothelial surface, but the dissect- then-fix protocol resulted in more creasing and distortion artifacts that were avoided with the whole-eyeball fixation. Overall, the CD values were higher if the dissect-then-fix method was used, and the uniformity of the cell mosaic was less. The median CD values for the central, mid-peripheral and peripheral regions following dissect-then-fix protocols were 7,693, 7,353, and 7,071 cells/mm(2) (average eight corneas at each location). If the whole-globe fixation was used, the median CD values were 6,098, 5,747, and 4,785 cells/mm(2). CONCLUSION: Cell density values in SEM can be very different according to the fixation method used. A distinct regional difference in CD was evident, which was more pronounced if the cornea was fixed prior to being dissected from the eye.

Animals↗
PubMed1980

Dictyostelium discoideum fruiting bodies observed by scanning electron microscopy.

The fruiting bodies of Dictyostelium discoideum, fixed in a vapor of 25% glutaraldehyde, were observed by scanning electron microscopy. The surface of the basal disk had rootlike ripples, sometimes with concentric rings of riblike striations at its periphery. The surface of the stalk had pleated and twisted ridges along its entire length, but no lateral projections. The spores were randomly orientated and had a crinkled surface. The surface of the lower part of the papilla had flattened ridges running horizontally. A slime coat remained in the region of transition between the stalk and sporangium, but not on the spores.

Dictyostelium↗
PubMed1980

Scanning electron microscopy and x-ray microanalysis of mineral deposits in lungs of a patient with pleural mesothelioma.

Scanning electron microscopy of lung tissue, ashed at low temperature, and obtained from an insulation worker who had died of pleural mesothelioma, showed the presence of numerous inorganic particles and fibres. A regional variation in fibre concentration in different tissue samples was found, and the size distribution of naked fibres and asbestos bodies was determined. By energy dispersive x-ray microanalysis the fibres were identified mainly as amphibole asbestos. This method also showed the presence of particles containing titanium and of fragments of diatom shells. Despite a mean concentration of 33 x 10(6) fibres per gram of dry tissue no significant lung fibrosis was found.

Adult↗
PubMed1990

Study of the elastic skeleton of intracranial arteries in animal and human vessels by scanning electron microscopy.

We studied the elastic skeleton of major cerebral arteries in rats, monkeys, and one human using scanning electron microscopy after hot formic acid extraction followed by freeze-drying. For comparison, we also examined the thoracic aorta and femoral artery of rats. The cerebral arteries of rats had one distinct internal elastic lamina connected to the thin adventitia with sponge-like medial elastic tissue. This internal elastic lamina had fenestrations, which we found to be less frequent in cerebral arteries than in extracranial arteries, and fold-like protrusions into the lumen. This finding has not been recognized before. Such protrusions were more prominent in cerebral arteries than in extracerebral arteries. At the apical intimal pad, the internal elastic lamina appeared to be continuous, making a honeycomb-like structure. The folds and fenestrations were numerous at the apex. There were no essential differences among species. Our study shows that the internal elastic lamina is not a simple sheet but part of the complicated architecture of the elastic tissue of the vessel wall. These differences in the elastic skeleton, including fenestrations and fold-like structures, in various sites of different arteries may explain the development of various localized vascular diseases.

Animals↗
PubMed1979

Scanning electron microscopy in the evaluation of neurosurgical neoplasms: a review of new approaches.

Present and potential applications of scanning electron microscopy (SEM) to the study of solid neoplasms, the lining of cysts, exfoliated cells, mineral deposits, and supporting tissues of the central nervous system (CNS) are discussed. Special features of the SEM image include a large field of view and depth of focus, high resolution, and a three-dimensional impression of surface topography. These features have contributed a clearer understanding of similarities between colloid cyst and olfactory epithelium. They demonstrated differences between glial and nonglial fibrils of selected CNS neoplasms. These features may ultimately enhance decisions, diagnosis, and study of neoplastic origins and spread within the CNS and cerebrospinal fluid. Special features of tissue examination by SEM include processing without the need of thin sections and elemental analysis by X-ray spectroscopy. These features have been applied to studies of calcium and thorium associated with meningiomas and a schwannoma.

Adenoma↗
PubMed1996

The three-dimensional architecture of the myosalpinx in the sheep as revealed by scanning electron microscopy.

The three-dimensional (3-D) architecture of the myosalpinx in the sheep was studied by scanning electron microscopy after the removal of interstitial connective tissue with NaOH digestion. In the extramural portion of the tubo-uterine junction, the myosalpinx is made up of densely packed, circularly arranged superficial fibers and of innermost loose fiber bundles following an almost longitudinal course. In the isthmus and ampulla, the myosalpinx is constituted by oblique bundles of variable length, which run around the tube and merge into the surrounding musculature, giving rise to a plexiform arrangement. The present 3-D observations demonstrate that the sheep myosalpinx consists mainly of single muscular fibers and more complex bundles which show a multiple spatial arrangement and a plexiform distribution. Such a muscular architecture is more likely suited for stirring rather than pushing the embryos and gametes through the tube.

Animals↗
PubMed1999

Light and scanning electron microscopy of the inner surfaces of resins used in direct pulp capping.

PURPOSE: To investigate with the scanning electron microscopy (SEM) the inner surface of the resin restorative used as a direct pulp capping. MATERIALS AND METHODS: Class V cavities were prepared on the facial surfaces of 90 intact monkey teeth, and the pulps were intentionally exposed with a carbide bur through the cavity floor. Each exposed pulp was capped with one of three commercially available adhesive resin systems (BondWell LC, GC; Imperva Bond, Shofu; Clearfil Liner Bond II, Kuraray). The cavities were restored with an adhesive resin and a hybrid resin-based composite. Histopathological changes of the mechanically exposed pulp were evaluated at 3, 30 and 60 days postoperatively. The interface between the resin and pulp tissues on the inner surface of the resin restorative was observed by SEM. RESULTS: Bacterial penetration along the cavity walls and pulp tissue could not be detected in any specimen. Slight inflammatory cell infiltration was the main initial reaction, while dentin bridge formation was the major long-term reaction in all groups. The resin surface adjacent to the etched cavity floor contained numerous resin tags corresponding to the dentin tubules. Remnants of pulpo-dentin complex, such as fragments of blood clots, pulpal cell, and dentin were also seen scattered along the inner resin surface.

Animals↗
PubMed1998

The microvasculature of the corpus luteum in pregnant rabbit. A scanning electron microscopy study of corrosion casts.

The vascular network of pregnant rabbit ovaries was studied by means of scanning electron microscopy (SEM) of corrosion casts, in order to evaluate the morphofunctional changes of the microcirculation of corpus luteum (CL). Pregnant rabbit ovary showed an overwhelming vascularization. Ovarian hilus displayed an increase in the arterial spirallisation. The arterial spiral pattern was present along the entire vessel course, up to CL tissues. The CL of pregnancy was supplied by wide vascular plexuses (2-5 plexuses were found in each pregnant ovary) whose major axis was about 2 mm. Luteal capillaries showed a tortuous course and were arranged in a three-dimensional, wide and rounded-meshed network. Postcapillary venoconstrictions were present. The venous drainage appeared more developed then the arterial supply. Tight artero-venous contacts in hilar, juxtamedullar and medullar regions of the ovary were observed. These results clearly show that the morphofunctional expression of CL of pregnancy is greatly dependent on its hemodynamic control. In particular, the increase of spirallisation exhibited by the arteries during pregnancy is likely to be considered a significant functional change. The spirallisation likely is a device for reducing the blood pressure through the CL. The artero-venous contacts, also previously described in hCG stimulated (pseudopregnant) ovaries, may support a counter-current like system that may allow a veno-arterial exchange of small molecules through the wall of the facing vessels. In addition, in 10-day pregnant rabbit CL the consolidation of a well-developed capillary network was revealed, which is a sign that the CL of pregnancy reached the full morphofunctional maturation. Furthermore, the CL of 10-day pregnant rabbit did not present significant capillary permeabilization and dilation or angiogenic processes, aspects that were previously found in stimulated periovulatory ovaries. Indeed, changes of the arterial supply and venous drainage of the CL of pregnancy were demonstrated. This suggests that the control of the blood flow through the CL of pregnancy may be transferred from the local capillary microcirculation to the regional artero/venous circulation. This may be probably related to the significant increase of the ovarian blood flow necessary for the maintenance of CL endocrine functions during pregnancy.

Animals↗
PubMed1990

Scanning electron microscopy of the sheathed infective larva and parasitic third-stage larva of Haemonchus contortus (Nematoda: Trichostrongyloidea).

Scanning electron microscopy was used to describe the infective and parasitic third-stage larvae of Haemonchus contortus, the large stomach worm of ruminants. Infective larvae are ensheathed in the cuticle of the second stage, so the descriptions are of the second- and third-stage cuticles. Both larval stages had an inner circle of 6 labial papillae, an outer circle of 6 labial papillae and 4 somatic papillae, and lateral amphidial pits. Infective larvae (cuticle of the second stage) had the 6 internal labial papillae on prominent bluntly rectangular lappets in a star-shaped arrangement around a large triradiate mouth, small triangular or round amphidial pits, flattened ribbonlike lateral alae, and phasmidial apertures opening on the ventral surface of the lateral alae. Parasitic third-stage larvae had the 6 internal labial papillae on small elevations without lappets around a small mouth; large, oval amphidial pits; ribbonlike lateral alae for most of their length, but with the anterior 30-40 microns of the alae cordlike; and phasmidial apertures on the body cuticle ventral to the lateral alae.

Animals↗
PubMed1988

Vascularization of male gonads in Blennius pavo (Teleostei, Blenniidae) as revealed by scanning electron microscopy of vascular corrosion casts.

The vascular architecture of male gonads of Blennius pavo is studied by scanning electron microscopy of vascular corrosion casts. Arterial supply to the gonads is by a branch of the first ventral segmental artery of the tail. From the surface of the gonads, this vessel gives rise to branches which supply testes, spermatic ducts, testicular glands, blind pouches, urogenital sinus and urogenital papilla. The testis has a rope-ladder-like capillary network around the seminiferous tubules, while in the testicular gland the capillary network is irregular in form. The spermatic ducts are found to have an exterior capillary network located in the compact connective tissue layer and an interior one, lying subepithelially. Urogenital sinus and urogenital papilla show a multilayered capillary network. Angioarchitecture in mature and immature gonads does not differ.

Animals↗
PubMed1986

Morphogenesis of the venous valves in the rat heart. I. Light and scanning electron microscopy.

Hearts from rat embryos ranging from 12.5 days gestation through birth were studied with light and scanning electron microscopy. Both valves of the sinus venosus are very prominent structures in the right atrium of the developing rat heart. The right venous valve is large and undulating and extends to the right atrioventricular canal. Many nodules are apparent on the surface of this valve by the thirteenth day. These nodules decrease in number as development progresses. The left venous valve is considerably smaller than the right. Neither valve shows signs of regression, and just prior to birth, both valves are very prominent. The right valve is so large that it almost divides the right atrium into two chambers. Based on these observations the rat may serve as a model for cor triatriatum dexter.

Animals↗
PubMed1985

Haemodynamically-induced intimal tears in experimental U-shaped arterial loops as seen by scanning electron microscopy.

Experimentally-induced U-shaped carotid loops, simulating arterial tortuosities and kinks were examined by scanning electron microscopy to seek flow-induced changes in the intimal surface. In 14 New Zealand white rabbits carotid arterial transplants were fashioned into U-shaped loops by microvascular surgery. The rabbits were sacrificed from 4 to 226 days post-operatively. Tears in the internal elastic lamina occurred in all loops from 5 days post-operatively and were predominantly transverse and localised about the greater curvature of the bends of each loop. Though initially denuded, all tears appeared endothelialised after 6 days, coalescing later as they increased in size and extent. In older animals only islands of wrinkled internal elastic lamina remained at those sites. Endothelial cells in the tears were small, numerous and polyhedral with raised nuclei. The lesser curvature of the three bends in the loops displayed some irregular wrinkling of the internal elastic lamina. In the three oldest animals a few longitudinal tears were observed on the lesser curvature of the main bend. The specific localization of intimal tears supports the concept that they were hemodynamically induced.

Animals↗
PubMed1979

Stereological analysis in scanning electron microscopy.

The traditional field of stereological analysis based on quantitative image analysis data is expanded to include scanning electron microscopy (SEM). Two major methodological advances enable useful results to be obtained: 1) Image recording of backscattered electrons using an annular semi-conductor detector; 2) Direct link between SEM and image analyser by means of an on-line coupling providing synchronisation of both sub-systems.

Computers↗
PubMed1984

Scanning electron microscopy of wound healing in rat embryos.

Wound healing in rat early embryos has been studied by scanning electron microscopy. Initially the wound gapes slightly and cells peripheral to the wound assume a cobble-stone appearance. Wound closure is quite rapid; some small wounds are almost closed within 10 min of incision. Wound closure is accompanied by the appearance of some elongated cells at the wound edge. These features are similar to, although less pronounced than, those which have been observed to accompany wound closure in amphibian and avian embryos. Healing of wounds made in the amnion is also accompanied by changes in the shapes of cells at the wound margins. Wound healing in embryos cultured in Hank's saline is similar to wound healing in embryos cultured in serum, suggesting that the macromolecular components of serum are not essential to wound healing. Cytochalasin B, which inhibits wound closure in amphibian embryos, does not inhibit wound healing in rat early embryos unless used at a concentration high enough to cause cell dissociation. Similarly chelation of the free calcium in the medium, which also prevents wound closure in amphibian embryos, does not inhibit wound closure unless the embryo is dissociating. Removal of free calcium does however cause collapse of the elevated neural folds. These observations suggest that the cellular mechanisms involved in wound healing are different in mammalian and amphibian embryos.

Animals↗
PubMed1983

Scanning electron microscopy of soy protein-induced damage of small bowel mucosa in infants.

Observations are reported by scanning electron microscopy (SEM) of soy protein-induced villous atrophy and mucosal recovery in two infants aged 5 weeks and 4 1/2 months. Whereas, by light microscopy, the mucosal lesions appeared similar, i.e., a flat mucosa, their appearance by SEM was different: the damage appeared more severe in the younger infant, although there was a shorter period of exposure to soy protein. The mucosal architecture was restudied 6 weeks after the initial biopsy. The degree of mucosal reconstruction was more advanced in the older infant--the one who showed less severe damage by SEM on the first biopsy. Although these investigations by SEM of damaged small bowel mucosa in soy protein intolerance did not contribute definite information to clarify the pathogenesis of villous atrophy in this condition, the injury was consistent with a lectin-induced toxicity, similar to the one postulated for celiac disease. SEM seems eminently suited to study of the effect of interactions between environment and host at mucosal surfaces; and finer gradations of damage to small bowel mucosa can be determined better by SEM, while this is not possible by light microscopy. Of interest was the rather extensive colonization of the mucosal surface by microorganisms in one of the two patients. However, the contribution of microbial colonization to mucosal damage could not be assessed.

Biopsy↗
PubMed1984

Nasal polyps. Scanning electron microscopy and artifact.

Nasal polyps are grossly oedematous tissue which has undergone considerable shrinkage when processed for scanning electron microscopy (SEM), converting the normally smooth surface into one with undulations. This shrinkage resulted in variable degrees of loss of the surface epithelium and thus gave rise to artifact. In its severest form, the entire surface epithelium was removed and the basement membrane exposed; lesser damage resulted in exposure of the basal cells, giving the previously described 'cobblestone' appearance. When the epithelium was intact, it was typical respiratory in type.

Adult↗
PubMedDate not supplied

Aspects of the T and B lymphocyte surface architecture in chronic internal diseases with immune component. Scanning electron microscopy studies.

Investigations on the T and B lymphocyte surface architecture were carried out by means of scanning electron microscopy (SEM) in 102 patients with various chronic internal diseases such as chronic hepatitis, diabetes mellitus, systemic lupus erythematosus, chronic lymphocytic leukemia, a.o. The clinical and biological examination performed in these cases reveled also some cytochemical, biochemical and immune disturbances. Emphasis is laid on the superiority of SEM, as compared with the E and EAC rosette tests, for the identification of T and B lymphocytes. Moreover, by detecting certain cellular anomalies, SEM can provide useful indications regarding the diagnosis, prognosis and therapy of the above mentioned diseases. Association of SEM with other clinical and laboratory investigations can either confirm, disapprove or even enhance the value of the morphological findings by electron microscopy.

B-Lymphocytes↗