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PubMed1977

Isolated metaphase chromosomes: scanning electron microscopic appearance of salt-extracted chromosomes.

Scanning electron microscopy of salt extracted, isolated metaphase chromosomes has been used to further the understanding of the role of proteins and DNA in chromosome architecture. Metaphase chromosome surfaces consist of numerous compact microconvules with an average diameter of 520 +/- 78 A which result from several orders of supercoiling. Treatment of isolated chromosomes with various salt concentrations ranging from 0.4 to 2.0 M NaCl revealed a longitudinal array of fibres within the chromatids as well as regions of coalesced nucleoprotein. The results demonstrate sensitivity of chromosome structure based on chromatin supercoiling, to progressive extraction of chromosomal proteins and DNA over the range of salt concentrations examined.

Cell Fractionation↗
PubMed1994

[Osteoclastic resorption of trabeculae in osteoporotic femoral head: a scanning electron microscopic study].

Osteoclastic resorption was studied by scanning electron microscopy on the trabeculae of femoral heads collected from 7 cases of aged women at an average age of 72.4 years, who underwent endoprosthetic replacement for intracapsular fracture of femoral neck. Femoral head trabeculae from 3 young adults killed in traffic accident served as control. The trabeculae of the femoral head formed round or roundish arch structure. The columnar trabeculae of the femoral head in the aged women showed overt osteoclastic resorption, manifesting thinning, tapering and perforation. The icicle-like trabeculae then became rounded, lost height and eventually turned into a small tubercle. As a result, the inter-trabecular space enlarged markedly. Under high magnification, on the trabeculae could be discerned oval, narrow oval or spindle-shaped Howship lacunae, which were various in size, depth and content, but all revealed punch-out edge. Around the lacunae the collagen fibril lamella normally covering the quiscient bone surface became resorbed sooner or later. During bone resorption, the inorganic component of the bone matrix were first dissolved and resorbed leaving behind rough and irregular collagen fibrils; nevertheless, the collagen might be degraded and resorbed first with residual inorganic crystals and irregular bone nodules. Then emerged in the Howship lacunae and surrounding area newly formed collagen fibrils and bone tissue, signifying reversal and new bone formation phases following the the bone resorption phase. In the aged women, however, this phenomenon was rather infrequently encountered, thereby leaving the bone turnover always in a negative balance state.

Aged↗
PubMed1978

Cleaning of scanning electron microscope specimens by puncture perfusion.

Puncture perfusion method was described for elimination of blood and tissue fluid in the scanning electron microscope specimens. It was also demonstrated that the puncture perfusion is of excellent use in cleaning the small samples including the human biopsy samples, which are hardly washed by the vascular cannulation.

Cytological Techniques↗
PubMed1976

Attachment of the inner sensory cell hairs to the tectorial membrane. A scanning electron microscopic study.

The residue of tectorial membrane insertion of cochlear inner sensory cell hairs was studied under a scanning electron microscope. In addition to the clear imprints resulting from outer sensory cell hair insertions, an adjacent medial row of bow-shaped imprints was noted on the base of the tectorial membrane. The relative position of these imprints corresponded to the location and the size of the inner cell hairs. These imprints were thus thought to arise from the insertion of the inner sensory hair cells. Such imprints were found only in the lower turns of the cat's cochlea, but not on the guinea pig tectorial membrane. Thus an actual physical contact between the tectorial membrane and the inner sensory cell hiars may exist in some species but not in others, and when there is physical contact, it is thought to be less firm than that of the outer sensory hair cells.

Animals↗
PubMed1985

A new method for obtaining scanning electron microscopic images of the reorganization process of human dermal microvascular endothelium in vitro.

A new method for obtaining scanning electron microscopic images of the reorganization process of endothelial cells has been developed. When covered with a collagen-coated disk, all the cultured endothelial cells reorganized on the collagen of the disk, which was easily taken out from the dish to process for SEM. The reorganization process could be divided into four stages: endothelial cell growth (Stage 1), reticular network formation (Stage 2), tubular structure formation (Stage 3), and cytolysis of the tube (Stage 4). Between Stages 1 and 2 the endothelial cells transformed from a cobblestone to a spindle-shaped pattern and fused each other, forming a board-like structure. Between Stages 2 and 3 break up of parts of the board-like structure and outflow of a necrotic mass from the centre of the structure occur. At Stage 3 a tubular structure is formed following enwrapping of the cleared centre by the surrounding endothelial cells. This method produces a means to study the angiogenesis in a variety of disorders including tumours and wound-healing process using SEM.

Cells, Cultured↗
PubMed1988

Effect of fluoride and cobalt on forming enamel: scanning electron microscope and X-ray microanalysis study.

The forming surfaces of enamel of rat incisors were examined by scanning electron microscope one hour after injection of either 5 mg/100 g body weight of sodium fluoride or 12 mg/100 g body weight of cobalt chloride. The cell debris from the surfaces of the separated incisors was either gently wiped off with soft facial tissues or chemically removed by treating with NaOH, NaOCl or trypsin. Best results to remove cell debris were obtained from 0.25% trypsin treatment. SEM studies revealed that the surface of the normal secretory enamel was characteristic in appearance with well-developed smooth prism outlines. In fluoride specimens the prism outlines were feathery in appearance, laced with protruding spine-shaped clusters of mineral crystals. In the case of cobalt treatment, prism outlines were less uniform and in some areas they were incomplete. The calcium concentration of surface enamel was significantly lower in the cobalt-treated specimens than those from control and fluoride-treated animals. The Ca:Mg ratio was also lower in cobalt-treated specimens as compared to control and fluoride-treated ones.

Animals↗
PubMed1990

Freeze fracture and scanning electron microscope studies on the nuclear envelope and perinuclear cytomembranes (parabasal apparatus) in the protozoan, Lophomonas blattarum.

Phase contrast, scanning electron microscope (SEM), and freeze fracture studies on the parasitic flagellate, Lophomonas blattarum, have demonstrated that the endomembrane system (parabasal apparatus) is highly ordered, restricted in position to a perinuclear zone at the anterior end of the organism, and is supported in this localized cytoplasmic region by overlapping sheets or plates of microtubules, previously called the calyx and axial filament, which may participate in supporting the nucleus-endomembrane system in a restricted region of the cell. Light microscope observations, SEM and freeze fracture data provide support to previous views that the rough- and smooth-surfaced endoplasmic reticulum are interconnected and attached to the outer layer of the nuclear envelope. The continuity of these membrane systems provides an orderly and restricted packing in the perinuclear cytoplasm since other areas of the cell may become filled with yeast. These flagellates are especially adept at phagocytosis of entire yeast. In yeast-laden cells, the flagella-nucleus-parabasal body-calyx-axial filament complex may separate from the remainder of the cell and assume a motile existence for a time. The significance of the described relationships, in addition to providing efficiency in endomembrane localization, may also reflect synthesis of enzymes and proteins by the RER and packaging in the SER, both of which are continuous. Granules characteristic of glycogen are concentrated around the SER which may be involved in glycogen metabolism. Although critical information is lacking, the endomembrane system may also be involved in the synthesis and morphogenesis of lysosomes, and perhaps peroxisomes. Lophomonas thus amplifies a highly ordered spatial relationship between the nuclear envelope and the ER.

Animals↗
PubMed1976

Immunospecific labeling of mouse lymphocytes in the scanning electron microscope.

Bone marrow-derived (B) and thymus-derived (T) Balb/c mouse lymphocytes were identified in the scanning electron microscope (SEM) by the immunospecific attachment of one of several kinds of large-molecular-weight markers distinguishable in SEM. These markers (tobacco mosaic virus, keyhole limpet hemocyanin, bushy stunt virus, and bacteriophage T4) could be modified with hapten groups and linked with anti-hapten antibody, in an indirect (sandwich) scheme, to hapten-modified anti-cell-surface antibody bound to the cell surface. Hapten-modified antibodies to B cell antigens (goat anti-mouse-immunoglobulin) or to T cell antigens (rabbit anti-mouse brain) were employed to identify these two lymphoid cell types in unfractionated spleen, mesenteric lymph node, bone marrow, and thymus cell populations. The topography of B cells was always indistinguishable from that of T cells. No surface features were found to be unique to either cell type. In suspension, the majority of B and T cells had one or no microvilli regardless of the tissue source of the labeled cells. Cells in suspension that had microvilli (usually 10% of the total cell population) were always unlabeled. However, after cell contact with a glass surface, approximately half of both the B and T cell population had a villous topography.

Animals↗
PubMed1976

[Exogeneous hair damage caused by bleaching and cold waving. A case report with scanning electron microscope studies].

A case of exogeneous hair damage caused by bleaching and cold waving is reported. The clinical picture showed brittle, lustreless, fallow hair. The light microscope showed irregular spreading of the cuticular cells. The scanning electron microscope revealed loss of the regular cuticular pattern, breakage of the edges of the cuticular cells, and wave-like separations of the cuticular cells from the cortex. The hair shafts showed multiple longitudinal indentations like seen on a tree trunk.

Adult↗
PubMed1980

On the microscopic anatomy of the rete testis a scanning electron microscopic and light microscopic study.

The microscopic anatomy of the transitional zone of the seminiferous tubules, the tubuli recti and the rete testis in adult rats was studied with histological serial sections, semithin sections and scanning electron microscopy. In paraffin section most transitional zones of the seminiferous tubules seemed to be obliterated by the modified Sertoli cells. Thinner plastic sections showed always a lumen, however. PAS--positive material, thought to represent masses of degenerating spermatozoa surrounded by Sertoli cell nuclei was found in 20% of transitional zones. About 80% of the tubuli recti had an initial widening which surrounded the bulging Sertoli cell bodies of the transitional zones. The intratunical rete consisted of five to seven intercommunicating channels, usually of small caliber. One wide communication was regularly present, however. The extratesticular rete was usually formed of two wide cavities. From their subdivisions the five to seven ductuli efferentes arose. The rete epithelium varied from very thin squamous to cuboidal and even columnar. The epithelial cells contained a flagellum surrounded by peripheral microvilli. Loose connective tissue was found under the epithelium of all parts of the rete.

Animals↗
PubMed2002

Field emission of individual carbon nanotubes in the scanning electron microscope.

The field emission of individual multiwall carbon nanotubes grown by chemical vapor deposition was measured in a scanning electron microscope. By using a sharp anode, we were able to select one nanotube for measurements in carefully controlled conditions. Single nanotubes follow the Fowler-Nordheim law, and the dependence of the field enhancement with interelectrode distance and nanotube radius is in good agreement with the recent model of Edgcombe and Valdré. Our results suggest that only nanotubes with the highest field enhancement factors, i.e., at least 8x higher than those of the average nanotube population, contribute to the emitted current in usual large area measurements.

Journal Article↗
PubMed1990

[Treatment of experimental HSV keratitis with recombinant human interferon (rHuIFN): a clinical and scanning electron microscopic study].

Treatment of experimental HSV keratitis in rabbits with rHuIFN alpha-1 instillations was studied Clinical and scanning electron microscopic observations revealed that local application of rHuIFN alpha-1 protected the target cells against virus invasion and restrained development of HSV keratitis. The initial punctate lesions did not expand uniformly but linearly to form dendritic patterns due to varying sensitivity of cells to virus.

Animals↗
PubMed1990

[Scanning electron microscopic observation of microvascular cast changes of bone following rigid limb immobilization].

This paper reported the results of scanning electron microscopic observation of microvascular cast changes of tibia following long cast immobilization of lower extremity. Beginning from 10 days after immobilization, the diameter of microvessels, particularly capillaries and sinusoids system in bone marrow, displayed severalfold enlargement compared with the control side. The changes became more obvious at 20 days. The number of sinusoids increased whereas the degree of dilatation declined at 40 days. The vessels within the epiphyseal region also showed more intense dilatation, growth of sinusoid-like structure and proliferation of sinusoidal and capillary system in marrow at 60 to 80 days. Similar changes in the cortical bone emerged as well at 80 days. The above-mentioned changes decreased at 100 days. These results pointed out that the pump effect of muscle on the blood flow in bone almost disappeared completely and disturbance of intraosseous venous drainage occurred. Under the condition of increased but unbalanced bone metabolism and turnover, the intraosseous microvascular system exhibited the described changes. Thus the total bone blood volume and the total bone blood flow increased.

Animals↗
PubMed1984

Scanning electron microscopic study of eye tissues.

We present a survey of our current investigations on lens and corneal tissue. Using scanning electron microscope techniques, we have studied lens fiber organization, lens capsule and subcapsular epithelium, the effect of Nd:YAG laser treatment on the lens, the endothelial effects of a relatively traumatic introduction of an intraocular lens, with and without sodium hyaluronate (Healon) pretreatment, and the epithelial reaction to foldings in Descemet's membrane (Descemet's folds).

Animals↗
PubMed1996

Scanning electron microscopic investigation of catheters for blood access.

Using blood-contacting catheters, infections, thromboses, and stenoses are among the most frequent complications. They are caused by surface properties of the basic material. Ion beam based processes such as ion implantation (silicone rubber) and ion beam assisted deposition (silver-based coatings) affect only the outer micron of the treated material surface; there is little effect on bulk properties. These processes were employed also in the production of large-bore catheters used for extra-corporeal detoxification. In a prospective study in 56 patients, 72 large-bore catheters were inserted into the internal jugular and subclavian veins and investigated after removal for bacterial colonization using a scanning electron microscope. In 24 patients 30 surface-treated catheters (Spi-Argent I n = 14; Spi-Silicone n = 16) were used. 42 untreated catheters used in 32 patients served as controls. Bacterial colonization was observed in 8.9% in contrast to 38.1% in untreated catheters. The scanning electron microscopic investigations showed in all catheters a low thrombogenicity. The ion beam based processes make the surface-treated catheters thrombus and infection resistant.

Catheterization, Central Venous↗
PubMed1998

A scanning electron microscopic study of the cleansing effectiveness of three irrigating modalities on the tubular structure of dentin.

This is a scanning electron microscope study of the cleaning effectiveness of three irrigating modalities on root dentin. When hydrogen peroxide was followed by sodium hypochlorite, it effectively cleaned the dentinal tubules of the root. When RC-Prep was reacted with sodium hypochlorite, it proved to be a more efficient irrigating method than the hydrogen peroxide and sodium hypochlorite solution. When a new improved RC-Prep with 15% carbanide peroxide was reacted with sodium hypochlorite, it proved to be a superior cleansing method for root dentin.

Carbamide Peroxide↗