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PubMed2003

A simple method to 'point count' silt using scanning electron microscopy aided by image analysis.

This study presents a simple method to 'point count' silt-sized grains using backscattered scanning electron microscopy together with image analysis. The work materialized out of the need to determine the heavy mineral abundance within silt obtained from coastal dunes to aid in the interpretation of dune weathering. This technique allows two broad mineral groups to be quantified according to their modal abundance. The groups are characterized by their dominant atomic elements present; atomic numbers >20 are classified as 'high' (metal oxides, zircon, monazite, carbonates, pyroxenes and amphiboles) and those <20 as 'low' (quartz, feldspars and organics). As a check on this technique, X-ray fluorescence was used. This showed a strong positive correlation (r2=0.85) with the developed point counting technique.

Image Processing, Computer-Assisted↗

PubMed2002

Vasculature of the ophthalmic rete in night herons (Nycticorax nycticorax): scanning electron microscopy of corrosion casts.

Vasculature of the ophthalmic rete (rete ophthalmicum) in the night heron (Nycticorax nycticorax) was studied using scanning electron microscopy of vascular corrosion casts and light microscopy on tissue sections. Most blood to the eyeball and a lesser volume of blood to the brain passed through the ophthalmic rete via the external ophthalmic artery. The collateral retial arterioles originated from the external ophthalmic artery forming a flat and fusiform-shaped arterial network at the ventrotemporal region of the eyeball. The arterial network was intermixed with a similar complex of the veins from the eye. The ophthalmotemporal artery, which supplied the eyeball posteriorly, and supraorbital and infraorbital arteries, which supplied the eyeball anteriorly, originated from the rete. Blood from the eye, which is a site of potential heat loss, drained into the ophthalmic rete via the ophthalmotemporal vein. On the casts of retial arterioles, slit-like cleavages at branching sites representing flap valves, which might play a role as sluice valves, were seen. In addition, marks of circularly running grooves, which might represent tufts of smooth muscle cells and might contribute to a sphincter activity, were observed. These anatomical specializations of the avian ophthalmic rete, involving parallel arrangement of arteries and veins, may function to facilitate counter-current heat exchange and to regulate blood pressure and volume to the eye and the brain.

Animals↗

PubMed1975

Hapten-sandwich labeling. II. Immunospecific attachment of cell surface markers suitable for scanning electron microscopy.

A hapten-sandwich procedure has been used for immunospecific labeling of cell surface antigens with markers visible by scanning electron microscopy. Antihapten antibody was used to link hapten-modified tobacco mosaic virus, bushy stunt virus, or hemocyanin to hapten-modified human erythrocytes. The antihapten antibody bridge was also used to link the hapten-virus marker to hapten-modified antibodies against mammary tumor virus on mouse mammary tumor cells, or against immunoglobulin receptors on mouse splenic lymphocytes. In all cases, labeling was highly specific. With this technique, it is possible to (a) compare morphological features of cells bearing differing cell surface antigens, and (b) examine the arrangement of specific antigenic sites on a cell surface or their distribution relative to membrane structures such as microvilli.

Animals↗

PubMed2000

A re-examination of the cellular reticulum of fibroblast-like cells in the rat small intestine by scanning electron microscopy.

The organization and arrangement of fibroblast-like cells in the rat small intestine were re-examined by scanning electron microscopy after removal of the epithelium and underlying connective tissue components by HCl hydrolysis. In the villi, the fibroblast-like cells had numerous slender processes, and formed a dense and elaborate network like a sieve. It consisted of a large number of circular structures (circles) with various diameters ranging from 0.3 microm to 5 microm formed by the twining of slender processes. In the upper area of villi, numerous fragmental protrusions which were considered to be mainly parts of immune-related cells such as lymphocytes, eosinophils and macrophages extended from the circles. The cells around each tubular gland enclosed it like a basket. These findings suggest that in addition to the function as a skeleton for the villi and glands, the fibroblast-like cells in the upper area of villi may play an important role in regulating the migration of the immune-related cells between the epithelial layer and the underlying lamina propria by their cellular sieve-like structure and contractile ability.

Animals↗

PubMed2004

Repair of fractured framework: scanning electron microscopy and energy dispersive X-ray spectroscopy.

Fractured metal prostheses can be analyzed for possible causes of failure using scanning electron microscopy (SEM). In this study, fractography is used to determine the cause of the failure and whether repair is practical. Energy-dispersive x-ray spectroscopy (EDS) is used to determine composition of the fractured prosthesis so that a repair process can be recommended. The technique is presented for the repair of a titanium framework for an implant-supported overdenture based on the analysis data.

Dental Prosthesis Repair↗

PubMed1977

A specimen carrier, storage disc system for scanning electron microscopy (SEM): evaluation of stainless steel as a substratum for cell culture in vitro.

A method of sample preparation for scanning electron microscopy (SEM) studies based on the use of stainless steel discs as a cell culture substratum is described in detail. A number of different cell lines were grown on stainless steel, and the growth patterns and biocompatibility of cells cultured on stainless steel were compared to identical cells cultured on aluminium, glass and plastic substrata. Stainless steel provides cells with an excellent growth surface which allows these cells to retain their normal growth characteristics and appearance. The non-toxic stainless steel discs can be manipulated through any combination of fixatives and organic solvents. The discs have been incorporated into a versatile system of sample preparation for SEM.

Alloys↗

PubMed1994

Description of the larva, diagnosis of the nymph and female based on scanning electron microscopy, hosts, and distribution of Ixodes (Ixodes) venezuelensis.

The larva, nymph, and female of Ixodes (Ixodes) venezuelensis are diagnosed using scanning electron microscopy, and the larva is described for the first time. This ixodid tick is recorded from the northern neotropics as a parasite of five species of didelphid marsupials and eighteen species of rodents (one sciurid, two heteromyids, eleven murids, two dasyproctids, and two echimyids). Collection records of I. venezuelensis are presented for Costa Rica, Colombia, Panama and Venezuela, with the Costa Rican records being new and extending the known range of this tick by at least 300 km. Altitudinally, I. venezuelensis has been collected between elevations of 24 and 2410 m with most collections between 100 and 800 m. The possibility that I. venezuelensis may be parthenogenetic is discussed.

Animals↗

PubMed1988

Microvasculature of the bear heart demonstrated by scanning electron microscopy.

Morphological features of the coronary microvasculature were examined in ten Black bears (Ursus americanus). Tissue samples were collected for scanning electron microscopy from five animals, and vascular casts of the coronary vessels were prepared from five. Each portion of the microvasculature examined had specific morphological characteristics which may contribute to the control of blood flow. All indications from the present study suggest that the structure of the coronary microvasculature in the Black bear is similar to that of mammalian species previously examined.

Animals↗

PubMed1995

Alterations in surface morphology of Candida albicans produced by rilopirox: a scanning electron microscopy study.

The topological changes produced in Candida albicans cells by incubation in vitro with rilopirox have been investigated by scanning electron microscopy. Rilopirox is a new hydroxypyridone compound with fungicidal activity and the effects of 1x MIC (2.9 micrograms/ml) and 4 x MIC (11.6 micrograms/ml) after 1, 12, 24 hours of incubation were evaluated. The morphological alterations produced by rilopirox are round shapes, collapsed cells, surface folds, clusters, holes and thorn-like extrusion. The effects of rilopirox are already evident at 1 x MIC and after 1 h but their frequency and severity are correlated with the time of incubation and the MIC.

Antifungal Agents↗

PubMed2000

Embryonic muscle development in rainbow trout (Oncorhynchus mykiss): a scanning electron microscopy and immunohistological study.

Embryonic muscle development was studied in rainbow trout (Oncorhynchus mykiss) at low and high temperature using scanning electron microscopy (SEM) and immunohistology. Somite development was described starting at stage 16 (Vernier JM. 1969. Ann Embryol Morphogen 4:495-520) for both temperatures, with special interest in their shape and size. Muscle differentiation, associated with somite growth, is characterized by a larger increase in height compared to width and by acquisition of a chevron shape. Thin structures such as striation, sarcomeres, and myofibrils within muscle cells and myotubes were observed starting at the eyed stage (stage 24). Immunohistological analyses showed appearance of embryonic fast myosin at stage 20 in the deep part of the somite. The area where myosin was expressed extended in the somite throughout embryonic development and the presence of myosin was observed in the entire somite at hatching (stage 30). Slow myosin was expressed in a monolayer of superficial cells at the eyed stage and during the entire embryonic development. Then it was expressed in a few layers of cells located in the red muscle area. These results suggest that muscle differentiation, characterized by myosin expression, is engaged at stage 20. Myogenesis starts in the deep part of the somite, near the notochord and progresses laterally to cover the complete somite at hatching when the somite is composed of muscle fibres exhibiting a high degree of maturity. No significant difference was observed in terms of muscular development between low- and high-temperature conditions. J. Exp. Zool. 286:379-389, 2000.

Animals↗

PubMed1975

A scanning electron microscopy study of the endothelial folds in normal and anastomosed common carotid arteries in albino rats.

The results of this scanning electron microscopy study show that the endothelial folds of the common carotid arteries of rats are composed of rows of 2 or 3 endothelial cells standing alongside one another on the underlying internal elastic lamina. If anastomosed arteries develop a stenosis the endothelial folds, instead of running longitudinally along the vessels, are rotated through 90 degrees to run transversely. The most important factor causing this change in direction of the endothelial folds is fibrosis of the arterial wall following damage to the blood supply of the vessel during dissection and anastomosis.

Animals↗

PubMed1975

Observations on the antibody-dependent cytotoxic cell by scanning electron microscopy.

The cytotoxic effect of human peripheral blood leucocytes on antibody-coated sheep erythrocyte monolayers has been investigated using scanning electron microscopy. Only a small proportion of leucocytes were found to adhere to the monolayers. A progressive destruction was observed beginning as small plaque-like areas of erythrocyte clearing which later became confluent. Three distinct cell types were found to be associated with the areas of lysis. No destruction was observed in control monolayers incubated for a similar period in the absence of either antibody of leucocytes. Surface changes in the erthrocytes adjacent to the leucocytes suggest that mechanical factors may be involved in erythrocyte lysis in this system. It is concluded that more than one leucocyte type may damage antibody-coated erythrocytes, possibly by a mechanism involving attachment to and mechanical disruption of the red cell membrane.

Animals↗

PubMed2002

A scanning electron microscopy study of Musca domestica larvae.

The micro-morphology of the house fly, Musca domestica larvae was studied by scanning electron microscopy (SEM). The ultra-structure of the mouth-hooks, oral ridges, spinulation of body segments and posterior spiracles, was photographed and described.

Animals↗

PubMed1991

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

The three-dimensional (3-D) architecture of the myosalpinx in the rabbit has been investigated by means of scanning electron microscopy after microdissection and the removal of interstitial connective tissue with KOH digestion. In the extramural portion of the tubo-uterine junction, the myosalpinx presents outer longitudinal bundles which form a well-defined continuous muscular layer extending towards the ampulla. Underlying this layer there are single muscular bundles which follow an uneven circular arrangement. At a deeper level the same bundles present a plexiform arrangement. Several bundles reach the base of the mucous folds and follow a discontinuous, approximately longitudinal arrangement. In the isthmus, the myosalpinx shows superficial longitudinal strips that abruptly bend sideways as they approach the ampulla, thereby enveloping the underlying muscular structure. The latter is arranged in the same way as at the extramural portion of the tubo-uterine junction, except for the lack of the outer longitudinal layer originating from the uterus. Our 3-D results revealed that the architecture of the rabbit myosalpinx consists of muscular bundles independent of one another that follow multiple spatial arrangements and form a complex network. Such a type of structure seems to be capable of stirring rather than pushing the embryo and gametes.

Animals↗

PubMed1991

Scanning electron microscopy study of small bowel biopsies in chronic diarrhoea in childhood.

In this study we have compared the results of Scanning Electron Microscopy (SEM) with Light- and Stereomicroscopy in a series of small bowel biopsies in children. In 9 cases displaying features of partial or subtotal atrophy, Light and Dissecting-Microscopy yielded similar results. The distinction between coeliac and non-coeliac chronic diarrhoea was only possible on clinical grounds, and by the immunological detection of specific antibodies. On SEM however coeliac patients showed characteristic alterations consisting of: absence of villi; prominent crypt outlets resulting in a mosaic appearance; concentric furrows running all around the openings; and downy brush feature at high power. The microvilli were loosely distributed and had an irregular pleomorphic outline; they often displayed a drumstick swelling of the tip and were bent. In contrast, non-coeliac chronic diarrhoea cases were characterized by a thick mucous layer on the mucosal surface, that made it impossible to visualize further changes. Peculiar vascular changes in lymphangiectasia and in sickle beta thalassemia could be detected only by Light Microscopy. In addition, in the lymphangiectasia case SEM allowed the detection of enteroadherent bacteria; and in the lambliasis case, of pseudomembranes. Absence of glycocalyx was noted both in controls and in patients. The results of this study point to a diagnostic utility of SEM particularly in the differential diagnosis of chronic diarrhoea; moreover they suggest that enteroadherent bacteria may not be pathogenic and that the absence of glycocalyx is not specific for allergic enteropathy as previously claimed.

Adolescent↗

PubMed1986

Measurement of single-cell DNA synthesis by pokeweed mitogen-stimulated mononuclear cells with combined light and scanning electron microscopy.

The response of peripheral blood mononuclear cells to pokeweed mitogen (PWM) stimulation was investigated with combined light (LM) and scanning electron microscopy (SEM). The DNA content of the nucleus of a cell (measured by fluorescence) was compared directly with the diameter and morphological features (by SEM). It was found that upon PWM stimulation lymphocytes transform into blast cells without measurable increase of diploid DNA content (4C) were not seen. The results of DNA fluorescence measurements were comparable with [3H]thymidine uptake profiles, both having peak values on Days 4 and 5 after the start of stimulation. Lymphocyte-enriched populations stimulated by PWM showed a small but distinct population of cells with a diameter of approximately 4-5 micrometers and having a tetraploid DNA content on Days 3, 4 and 5 after the start of stimulation. This reflects the cells' ability to divide in response to mitogen stimulation. SEM showed no characteristic cell-surface morphology for blast cells with increasing DNA content.

DNA↗

PubMed1986

Adjunctive use of scanning electron microscopy in bite mark analysis: a three-dimensional study.

An examination of a case in which adjunctive use of scanning electron microscopy (SEM) demonstrated the presence of unusual three-dimensional characteristics in a bite mark. Despite the fact that many bite marks do not show "depth," demonstration of the presence of this third dimension can produce significant data for evidentiary purposes. In some instances, these data may transform what seem to be class characteristics of a bite mark into individual characteristics and thus impart much more uniqueness to the evidence. Because of the high level of resolution and magnification of SEM, some three-dimensional characteristics not visible to the eye can be shown quite clearly by its use. Emphasis will be given to the value of SEM as a tool of the forensic odontologist in bite mark analysis.

Adult↗

PubMed1983

[Vascularization of the cervical trachea and its clinical relevance. A scanning electron microscopy study on corrosion casts].

The angioarchitecture of the cervical trachea of the rat as a model was studied using scanning electron microscopy of vascular corrosion casts. Four different types of vascular pattern are described. 1. Supplying and draining vessels of the first order (Superior and inferior thyroid arteries, and inferior thyroid veins) situated within the peritracheal tissue at the lateral sides of the trachea. 2. The vessels arising from them, which have a horizontal course and lie within the intercartilaginous membrane (vessels of the second order). 3. The vessels of the third order branching from those of the second order, perforating the intercartilaginous membrane and again running vertically within the tracheal mucosa. 4. Vessels of the fourth order forming the capillary plexus of the tracheal mucosa, consisting of irregular (pars fibrocartilaginea) or rectangular (pars membranacea) meshes. The clinical relevance of the vascular patterns of the trachea is discussed in respect to ischemic tracheal lesions.

Animals↗