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Results for “scanning electron microscope”

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PubMed1991

Scanning electron microscopic studies of tissue elastin components exposed by a KOH-collagenase or simple KOH digestion method.

A KOH-collagenase or simple KOH digestion method was employed for scanning electron microscope (SEM) studies of elastin components in the rat thoracic aorta, mouse urinary bladder, and human ductus deferens. Immersion of the fixed tissues in 30% KOH solution for 8-10 min at 60 degrees C, with or without subsequent collagenase treatment, successfully removed collagen fibrils and basal laminae while leaving cellular and elastin elements unchanged at their original shapes and locations. The internal elastic lamina of the rat aorta appeared as a solid sheet formed by elastin fibrils 0.1-0.2 microns thick, while the medial elastic laminae were more fibrous because of the presence of numerous fine elastin fibers on their surface. Adventitial elastin fibers were of a cord-like shape complicatedly entangled among the adventitial fibroblasts. These fibers were seen as bundles of fibrils 0.1-0.2 microns thick. In the mouse urinary bladder, elastin formed a thin lace-like sheet just beneath the serosal covering of the peritoneum. This sheet was composed of small bundles of fine (0.1-0.2 microns thick) fibrils. The external connective tissue of the human ductus deferens was made up of a three-dimensional loose network of elastin fibers 0.1-1.5 microns thick. These fibers also appeared as bundles of the fine fibrils. These findings indicate that the present method is useful for SEM studies of elastin as well as cellular components in various tissues and organs. This study also maintains that elastin fibers and laminae are basically composed of unit fibrils of 0.1-0.2 microns thickness. As elastin components are arranged specific to individual organs and tissues, it is reasonable that these components are concerned in the characteristic mechanical properties of these tissues and organs.

Animals↗

PubMed1979

Toxoplasma Gondii: scanning electron microscope studies on the small intestine of infected and uninfected cats.

The mucosal surfaces of villi from the small intestine of cats infected with Toxoplasma gondii were studied with the scanning electron microscope and compared with those from uninfected control cats. In uninfected cats villi were predominantly leaf shaped and were lined with ridges; goblet cell openings could be seen. The enterocytes had a hexagonal surface outline and were dome-shaped. Infected cats had both normal and abnormal villi. Injured villi were shortened and attained a broad leaf shape, often with blunt edges. Enterocytes containing oocysts were enlarged, and microvilli were resolvable only on these surfaces. Ruptured cells from which parasite discharge had occurred were seen. Oocysts were observed and possessed a smooth coat.

Animals↗

PubMed1985

A scanning electron microscopic study of the mesencephalic trigeminal nucleus in duck and rabbit.

The mesencephalic trigeminal nucleus (MTN) cells of both young and adult ducks as well as of rabbits were investigated by scanning electron microscope. The rabbit showed only ovoid unipolar cells, while the duck also presented polyhedral cells. Few of these latter revealed processes originating from their surface and were recognized as multipolar cells. Some differences between the MTN cell surface of young and adult ducks were noticed. Synaptic bulbs were observed on the MTN cells in both duck and rabbit.

Animals↗

PubMed1994

Scanning electron microscope observation of adherence of Candida albicans to cultured keratinocytes.

The role of antigen 6 in the adherence process of Candida albicans serotype A to cultured keratinocytes was examined with a scanning electron microscope. The number of adhered organisms was significantly lower for the antigen 6-deficient mutant strain than for the antigen 6-positive parent strain (P < 0.001). Fibril- or strand-like structures bridging the organisms and the keratinocytes were found to develop during the later stages of adherence.

Bacterial Adhesion↗

PubMedDate not supplied

X-ray spectrometry and spectrum image mapping at output count rates above 100 kHz with a silicon drift detector on a scanning electron microscope.

A third-generation silicon drift detector (SDD) in the form of a silicon multicathode detector (SMCD) was tested as an analytical x-ray spectrometer on a scanning electron microscope. Resolution, output count rate, and spectral quality were examined as a function of the detector peaking time from 8 micros to 250 ns and over a range of input count rate (dead time). The SDD-SMCD (50 mm2 active area) produced a resolution of 134 eV with a peaking time of 8 micros. The peak width and peak channel were nearly independent of the input count rate (at 8 micros peaking time, the peak width degradation was 0.003 eV/percent dead time and peak position change was -0.7 eV over the dead time range tested). Maximum output count rates as high as 280 kHz were obtained with a 500 ns peaking time (188 eV resolution) and 500 kHz with a 250 ns peaking time (217 eV resolution). X-ray spectrum imaging was achieved with a pixel dwell time as short as 10 ms (with 1.3 ms overhead) in which a 2048 channel (10 eV/channel) spectrum with 2-byte intensity range was recorded at each pixel (scanned at 128 x 128). With a 220 kHz output count rate, a minor constituent of iron (present at a concentration of 0.04 mass fraction or 4 weight %) in an aluminum-nickel alloy could be readily detected in the x-ray maps derived from the x-ray spectrum image database accumulated in 185 s.

Journal Article↗

PubMed2006

[Observation the electroporation of blood cells in vitro by scanning electron microscope].

OBJECTIVE: To observe changes on cell membrane in blood cells after they were been electrified. METHODS: Blood were electrified for 5, 10, 20, 30 s, 1 min respectively, and Scanning electron microscope was used to detect the changes on their cell membranes. RESULTS: Pores were detected both on electrified erythrocytes and leukocytes with round or ellipse shapes. The erythrocytes often have one or more pores while the leukocytes often have more pores looked like cribble. The rates of perforated cells were increased with the prolonging time of electrification, 5 s with 6% and 1 min increased to 40%. CONCLUSIONS: Alternating current can cause the cell perforating, and the rates of perforated cell were increased with the prolonging time of electrification.

Adult↗

PubMed1990

Quantitative assessment of scanning electron microscope defects in uncombable-hair syndrome.

Uncombable-hair syndrome is a rare disorder of scalp hair that starts early in childhood. It is characterized clinically as unruly hair and by scanning electron microscopy as longitudinally grooved hairs with a triangular cross section. Because of the controversy of inheritance and prior reports of similar changes in normal and other hair disorders, we performed a quantitative scanning electron microscopic assessment of four patients with uncombable-hair syndrome, first-degree relatives, and nonaffected controls. Our results indicate that longitudinal grooving of scalp hair is a common occurrence, and that for clinical changes to be apparent, approximately 50% of hairs must be affected.

Child↗

PubMed1998

Scanning electron microscopic and cytochemical analyses of alveolar and peritoneal macrophages of mice, dogs and cats.

Alveolar and peritoneal macrophages (MPs) of mouse, dog and cat were compared in relation to their scanning electron microscopic features and the lysosomal activities of nonspecific esterase, acid phosphatase, and beta-glucuronidase. The long spindle shape of peritoneal MPs differed from the spherical form of alveolar MPs in all species. There was no difference in the morphological findings among the three animals. Murine alveolar and peritoneal MPs were strongly positive for all three enzymes. Canine and feline alveolar and peritoneal MPs were strongly positive for acid phosphatase and beta-glucuronidase, but weakly positive for nonspecific esterase. These results strongly suggest that acid phosphatase and beta-glucuronidase can be used as markers of the MPs in healthy dogs and cats.

Acid Phosphatase↗

PubMed1988

Scanning electron microscopic observations of the ependymal cell and the subependymal layer of the third brain ventricle in the rat.

This investigation was undertaken to clarify the three dimensional ultrastructure of the subependymal layer in relation with the ependymal cell layer in rat brain using the scanning electron microscope (SEM). The subependymal layer existing below the ependyma of the third ventricle in the brain of mature albino rats was examined with S E M. The hypothalamus freshly excised after median sagittal section was treated by collagenase with or without trypsin for a short while to remove the ependymal cells at the ventricular wall. After the enzymatic pretreatment of the specimen, many ependymal cells were removed and the subependymal layer was partially exposed. Most of the ciliated ependymal cells remaining at the ventricular wall extended long, single basal processes which then penetrated into the subependymal layer. The subependymal layer was composed of a delicate framework of thin processes of glial cells, ependymal cells and, in addition nerve cells. Scattered among the neuropil just beneath the ependymal cell layer, there were relatively small, globular subependymal cells. Occasionally, there were large bundles of unmyelinated nerve fibres in the subependymal layer. The individual nerve fibres distinctly showed many axonal varicosities within the fibres. Intermingled with the nerve fibres, glial processes of various forms were present. The structure of the ependymal cells and the subependymal layer was compared with the findings already reported in the studies using light and transmission electron microscope.

Animals↗

PubMed1979

Scanning electron microscopic analysis of the linings of the fourth ventricle in the domestic fowl.

Surface features of the ependymal linings of the fourth ventricle in the fowl were analyzed employing the scanning electron microscope (SEM). On the floor of the median sulcus, each ependymal cell has a solitary cilium, whereas on both sides of the sulcus, cilia are so densely distributed that the details of the underlying cell surface are usually obscured. On the roof of the fourth ventricle, except for the surface of the ciliated groove where numerous cilia are present, the ependymal cells are polygonal in shape, and the center of each cell possesses an aggregate of ten to twenty cilia. Cell surfaces of the choroid tela are entirely covered with delicate microvilli and possess clumped cilia. The ependymal cell surfaces of the area postrema are dome-like in shape. Each ependymal cell has a solitary cilium and shows a smooth surface free of microvilli.

Animals↗

PubMed1980

[Scanning electron microscopic studies of diseases fingernails by means of a casting technic].

By a cast method (silicone resins) which allows a form-fitting reprint of nail-plate relief are made scanning electron microscopic studies of healthy and sick nails. In this way a form-fitting restitution of the surface-relief is guaranteed up to magnifications of 5000:1. Thus it is possible to get a better impression of the affected nail-structure. The exactitude of this nail-structure-representation cannot be reached by normal light microscopy. This method is very simple and quickly to use. Nail-changes in onychoschizia, subungual hematoma and in senile nails are shown.

Aging↗

PubMed2000

A comparative scanning electron microscopic investigation of the efficacy of manual and automated instrumentation of root canals.

The cleaning effectiveness of automated and manual root canal instrumentation was investigated with the aid of a scanning electron microscope. Hand instrumentation was performed with K-Flexofiles used in a reaming working motion and according to the step-back technique and with Hedstrom files used in a filing motion. Automated preparation was performed with the KaVo-Endo Flash device featuring torque-limited rotation using K-Flexofiles, as well as with the mechanical ProFile system using rotary nickel-titanium instruments. Twelve teeth each with either straight or curved root canals were instrumented to size 40. After cracking the roots longitudinally (n = 120), the amount of debris and smear layer were quantified on the basis of a numerical evaluation scale (1 through 5). Comparison of manual instrumentation with the automated KaVo-Endo Flash resulted in an equivalent degree of canal cleaning. Complete cleanliness was not achieved by any of the techniques and devices investigated. Best instrumentation results, especially in curved canals, were obtained with rotary ProFile instruments.

Automation↗

PubMed1987

Scanning electron microscopic study on the angioarchitecture of glomeruli in experimental toxemia of pregnancy in the rabbit.

Experimental toxemia of pregnancy in late gestation in rabbits was induced by constricting the aorta below the renal arteries on day 21 of gestation. Light and transmission electron microscopic examination of glomeruli on day 29 revealed only a slight swelling of endothelial cells. The angioarchitecture was also investigated using scanning electron microscopic examination of methyl methacry corrosion casts of the glomeruli. The kidney in experimental toxemia was characterized by a reduction of glomerular vessel diameter compared to that of normal pregnant rabbits. This probably resulted from enlargement of the endothelial cells, suggesting a reduced blood supply to the glomerulus. These findings suggest that interference with the blood supply to the pregnant uterus is an important factor in the development of the renal lesion of experimental toxemia of pregnancy in the rabbit.

Animals↗

PubMed1976

Light and scanning electron microscopic studies on the esophageal spines in the Pacific ridley turtle, Lepidochelys olivacea.

The peculairly specialized esophagus of the Pacific ridley turtle, Lepidochelys olivacea, was described by light and scanning electron microscopic studies. The esophagus is lined by a stratified squamous epithelium with remarkable keratinization, and its major part forms a number of large spines which have been called "pharyngeal teeth." The epithelium consists of three strate: stratum germinativum, stratum spinosum and stratum corneum. The surface of the spine is covered by a scaly keratin of possibly sloughing cells, and the cornified layer on the spine is very thick (more than 100 mu), reaching 3 to 7 times the depth of the corresponding layer in other parts. This peculiar structure in the marine turtle without toothed jaws prabably is used for breaking food into small pieces.

Animals↗

PubMed1991

Scanning electron microscopic observations of three-dimensional structure of the rat pancreatic duct.

To understand the fine, three-dimensional structure of the pancreatic duct, we made corrosion casts of rat pancreatic ducts and obtained biological specimens of rat pancreatic tissues for scanning electron microscopic observation. We observed the corrosion casts and the inner surfaces of the pancreatic duct specimens, using scanning electron microscopy. A comparative study between casts and specimens demonstrated the exactitude of our corrosion casts. These findings revealed the following facts: 1) The pancreatic ductal system had an almost tree-like shape, but parts of the intercalated ducts anastomosed with each other; 2) Intralobular ducts branched almost at a right angle from the interlobular ducts. Intercalated ducts, which branched off from the intralobular ducts, wound and forked into two branches, without any decrease in thickness. The intercellular secretory canaliculi extended from the central lumina, running straight through the center of the acini, close to the cell bases; 3) In pancreatic ducts, every lumen was covered with microvilli. The diameters of these microvilli were uniform (about 0.1 micron), but the heights were variable, even within a given pancreatic duct.

Animals↗

PubMedDate not supplied

Early changes of experimentally induced cerebral aneurysms in rats: scanning electron microscopic study.

To obtain information about the early changes of experimentally induced cerebral aneurysms in rats, the luminal surface of branching areas of their cerebral arteries was examined with a scanning electron microscope. At the branching sites of major cerebral arteries in the control animals, the intima just distal to the apex markedly protruded into the lumen forming a linear bank-like intimal pad. Along and distal to this pad, there was a shallow long groove (juxta-apical groove). Such grooves were much deeper and wider in experimental animals than those in the control rats. By studying various stages of early aneurysmal changes, cerebral aneurysms were proven to develop from such grooves. In deep juxta-apical grooves and small aneurysms, round regenerated endothelial cells with a large number of microvilli were diffusely present. Degenerated cells with balloons and craters were observed intermingled with such regenerated cells. Interendothelial gaps were also seen. The present study showed the complex structure of the apex of arterial bifurcation in rats, including bank-like intimal pads. Such complex structures of the branching sites were considered to be responsible for the initiation of cerebral aneurysms due to endothelial injury possibly caused by turbulent flow there.

Animals↗

PubMed2005

Microvasculature of the retina, ciliary processes and choroid in the North American raccoon (Procyon lotor) eye: a scanning electron microscopic study of corrosion casts.

We have studied the vasculature of the retina, ciliary processes and choroid in the North American raccoon (Procyon lotor), a nocturnal mammal, using light and scanning electron microscopic examination of corrosion casts. We carried out an identical study in the crab-eating macaque (Macaca fascicularis), which forages only during the daytime, in order to compare the ocular vasculature with that of nocturnal mammals. Our observations in raccoons demonstrated a photoreceptor layer associated with rich lymph and a poorly vascularized retina. The meridian region of the eye, which lies in the horizontal plane and pass around the optic disc, had a markedly sparse capillary network. This horizontal sparse vascular band may correspond to a visual streak. Ciliary process capillaries were delicate, and formed a well-developed and compact network. Choriocapillaries were quite thin and formed a coarse capillary network. This contrasted with the dense retinal and well-extended choroidal capillary networks noted in the macaques. Our findings suggest that the sparse retinal capillary network in raccoons is extremely beneficial for photon capture, thereby allowing the raccoon to see well at night, as the retinal vessels restrict the inflow of photons toward the photoreceptors. The well-developed lymph probably compensates for the sparse retinal capillaries and choriocapillaries and nourishes the retina in the nocturnal raccoon.

Animals↗

PubMed1992

Scanning electron microscopic study of primary teeth in X-linked amelogenesis imperfecta.

Exfoliated primary teeth from a boy and a girl from a family with X-linked amelogenesis imperfecta (XAI) were studied by scanning electron microscopy. Teeth from the boy featured multiple shallow depressions on the enamel surface interspersed with deeper tubular voids. Shallow depressions and similar tubular defects were also apparent in control teeth from an unaffected individual but these were less frequent, irregularly distributed and less marked. Teeth from the heterozygous girl had broad furrows running longitudinally from the cusp(s) of the tooth cervically. These furrows were formed by a series of saucerized depressions which merged together in some areas. The bases of these depressions featured tubular voids extending into the enamel. These similar voids in teeth from both boy and girl probably represent enamel prism spaces vacant because of defective enamel protein synthesis and/or mineralization. Although the scanning electron microscopic features of teeth from females observed in this and previous studies of XAI differ, the enamel appears to be more similar in males with differing clinical XAI phenotypes.

Amelogenesis Imperfecta↗