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PubMed2000

The vascular bed in the rabbit ear: microangiography and scanning electron microscopy of vascular corrosion casts.

The vascular bed of the rabbit ear has been studied with light microscopy, microangiography and scanning electron microscopy of resin casts in a series of 20 ears. The major arteries supplying the ear were the central and rostral auricular branches of the caudal auricular artery. The caudal auricular branch was not observed, except as a small vessel supplying the rostral auricular base. The central auricular branch supplied blood to most of the auricular integument and was surrounded by capillaries extended from those supplying the skin. The periarterial capillaries formed a fine, compact network in the tunica media and were closely related to the central auricular branch. Evidence is presented suggesting that this vascular mechanism has a counter-current heat-exchange function for regulating body temperature. The artery had the well-developed internal elastic lamina and intimal cushions that regulate blood flow at the branching sites. A number of arteriovenous anastomoses were also observed between arterioles and venules, particularly in marginal regions of the ear. The intimal cushions and arteriovenous anastomoses might play an additional role in thermoregulation by regulating local blood flow in the ear.

Angiography↗
PubMedDate not supplied

Scanning electron microscopy after cytologic examination of urinary cells: lack of diagnostic advantage using combined microscopy.

A simple method for combined light microscopy (LM) and scanning electron microscopy (SEM) of urinary sediment is described. Spontaneously voided cells were routinely collected onto a filter for cytologic study. Individual cells were photographed and demarcated by an ink grid pattern and puncture marks in the filter. The filter was prepared for SEM. The cells that were studied by LM could be readily located and examined by SEM. This study showed the importance of identifying individual cells before observation by SEM since cells with similar appearances by LM may have markedly different features by SEM, and vice versa. The results obtained in a series of patients with transitional-cell bladder carcinoma indicate that degenerative changes in voided urothelial cells negate the utility of SEM as a routine screening tool.

Carcinoma, Transitional Cell↗
PubMed1984

Scanning electron microscopy of experimentally induced hepatocellular carcinoma.

Hepatocellular carcinomas (HCC) induced in rats by diethylnitrosamine were observed by light microscopy (LM) and scanning electron microscopy (SEM). Liver cirrhosis did not develop. The tumors were of 4 types; trabecular, glandular, adenoid and hyperplastic nodular (HN). SEM demonstrated that trabecular lesions were packed with many layers of HCC cells which had in some places bile canaliculi on the intercellular surfaces with sparse microvilli. Glandular lesions were composed of gland-like structures having columnar or cuboidal cells with numerous microvilli on the hemispherical apex. Glandular lumens were bordered from intercellular spaces by the zona occludens. The glandular structures were derived from the exterior of the trabecular lesions and were closed at both ends, as confirmed by reconstruction of serial sections. Adenoid lesions, which had gland-like structures in the trabecula, were often observed between purely trabecular and purely glandular lesions. HN-type lesions composed of two-cell-thick plates were mostly located at the peripheral parts of the HCC tumor and were continuous with other lesions. HN-type lesions had markedly dilated bile canaliculi and well-developed microvillous projections on the intercellular surfaces. The HN-type lesions had structures similar to those of late HN. The existence of lesions indistinguishable from late HN in the periphery of HCC tumors indicates the HCC develop from HN. In summary, the rat HCC were of 4 types of lesions which had characteristic histological and cytological structures, but which were connected with each other, changing gradually from one to the other.

Animals↗
PubMed2002

Evaluation of exhibits from a murder case using the lead isotope method and scanning electron microscopy.

We have used a combination of lead isotopes and scanning electron microscopy to determine the relationships between different exhibits in a murder case. Samples involved lead projectiles removed from the deceased's head and a pillow, lead-rich scrapings and particles (gunshot residues) from spent cartridges and a silencer, and particles from a pillowcase. The lead projectiles had the same isotopic composition. with the lead being derived from the same dominantly geologically old source(s). The lead smear from the silencer had the same isotopic composition as the projectiles, and the lead was probably from the same source. The particles from the spent cartridges had varying elemental compositions ranging from PbO to PbCuZn +/- Ba with or without Si and are consistent with derivation from the primer. The lead isotopic compositions of the particles from the spent cartridges show some variations, but these are markedly different from those of the projectiles, indicating lead from a mixture of geologically old and geologically young lead. The particles from the pillowcase were extremely small (usually <50 microm size) and showed varying isotopic compositions, some consistent with the gunshot residue from the cartridges. As the exhibits had been handled extensively prior to the present investigation, including some being sent to North America, there is a high likelihood that handling was not done in clean room environments and may have been contaminated. In this instance, as we were concerned about contamination, especially of the pillowcase, we felt contamination negated use of the results for assistance in proving the innocence or guilt of the accused. A combination of high-precision lead isotope measurements with scanning electron microscopy provides a powerful tool for forensic investigations if precautions are taken in handling the exhibits.

Firearms↗
PubMed1994

Light and scanning electron microscopy of greenbug aphid damage in wheat using the same section.

A method has been developed to enable correlative light microscopy (LM) and scanning electron microscopy (SEM) on the same section of wheat (Triticum aestivum L.) leaves infested by greenbug aphids (Schizaphis graminum Rondani). Segments of infested leaf tissue were fixed, embedded in paraffin, sectioned, and affixed to slides by standard histological techniques. Serial sections were viewed by LM as temporary mounts in xylene. Sections of interest were identified and re-embedded in fingernail polish, affixed to aluminum stubs, freed of polish with ethyl acetate or acetone, and sputter-coated for SEM. SEM of re-embedded leaf sections showed excellent preservation of leaf anatomy. The same aphid tracks and regions of cell damage identified by LM were visible. SEM increased resolution and provided a much clearer sense of the three-dimensional relations involved in the interaction between plant and insect.

Animals↗
PubMed1993

Microcirculation of the extrahepatic biliary tree: a scanning electron microscopy study of corrosion casts.

The microvascular arrangement of the extrahepatic biliary tree of the rat was studied by light microscopy (LM) and scanning electron microscopy (SEM) of vascular corrosion casts. The plexus that encircles the lumen of the common bile duct, observed by LM, showed a network of vessels of different diameter situated under the epithelium in the lamina propria. Parallel SEM observations of the same structure demonstrated the presence of 2 main vascular layers: an outer arterial and venous layer, corresponding to the larger vessels seen by LM, and a richer inner capillary layer just under the epithelium. On the luminal part of the corrosion casts, there were many round avascular empty pits that corresponded to the presence of small acinar glands distributed along the epithelium of the common bile duct. The rich subepithelial capillary network present in the rat, an animal without a gallbladder, may play an important role in the reabsorption of water and solutes from bile. Moreover, in pathological conditions (e.g. portal hypertension), liver blood flow may take a preferential collateral route through the intrahepatic peribiliary plexus into the relatively large diameter vessels of the extrahepatic peribiliary plexus because of the continuity of the 2 plexi.

Animals↗
PubMed2005

Musculoskeletal responses of 2-year-old Thoroughbred horses to early training. 8. Quantitative back-scattered electron scanning electron microscopy and confocal fluorescence microscopy of the epiphysis of the third metacarpal bone.

AIM: To characterise and explain the increase in density evident by computerised tomography (CT) and radiography in companion studies as a response to training, in bone in the palmar and dorsal regions of the condyles of the third metacarpal bone (Mc3) of 2-year-old Thoroughbred horses. METHODS: Compositional back-scattered electron (BSE) imaging in scanning electron microscopy (SEM) and confocal scanning laser microscopy (CSLM) were conducted on polymethyl methacrylate (PMMA)-embedded mediolateral slices of the right distal Mc3 from seven 2-year-old Thoroughbred horses trained on a racetrack and seven untrained horses kept at pasture. One left Mc3 from each group was studied in transverse section planes. This study focussed on regions of Mc3 found to differ in density between the trained and untrained horses in companion studies using CT and radiography. RESULTS: The increase of bone density in the condyles of Mc3 in trained horses compared with untrained horses occurred, without prior osteoclastic resorption, via the deposition of new bone on pre-existing internal surfaces. Within prior marrow spaces of cancellous bone, there was also rapid formation of immature strands and fronds of bone which were more cellular and mineralised, and more lamellar bone tissue was deposited on these new scaffolding elements in the trained horses. Both resulted in increased bone volume fraction (BVF). The microscopic mineralisation density of the bulk of the new tissue was lower than in pre-existing bone, and CT and radiography underestimated the increase in BVF. The new tissue was thus probably less stiff at the microscopic scale than pre-existing bone, though its addition would stiffen the global structure. CONCLUSIONS: In Mc3 of all the trained horses, there were obvious differences in microscopic structure compared with those from the untrained horses. Moderate, industry-standard levels of exercise used to prepare young horses for racing induced the formation of new bone in non-bone spaces in bone tissue, such that the bone organ should better withstand later increased levels of exercise.

Animals↗
PubMed1982

A technique for quick fixation of whole Drosophila and other small insects for scanning electron microscopy.

A procedure for fixing small insects in natural postures for scanning electron microscopy is reported. Anesthetized insects are partially restrained using a depression slide and a coverslip while preliminary fixation is carried out and wings and legs are positioned with a fine brush. Following this, fixation is completed and the insect is prepared for scanning electron microscopy by essentially standard procedures, which may include critical point drying. Figures illustrate, however, that critical point drying is not necessary for more rigid parts of the exoskeleton. Use of this procedure assures naturally disposed parts even when only a single specimen is available.

Animals↗
PubMed1977

Morphology of human cells, carrier of measles virus, using nomarski optics and scanning electron microscopy.

A human cell line (Lu106) carrier of measles virus was studied in a Nomarski interference-contrast microscope (NICM) and a scanning electron microscope (SEM). The results from this were correlated with fine structure findings obtained from analyses made in the transmission electron microscope (TEM). In both the NICM and SEM it was possible to identify intracellular perinuclear structures, which most likely represent aggregates of measles nucleocapsids. These structures appeared in the NICM as opaque vesicles and in the SEM as bulges in the flattened cells. The SEM also proved to be used for determining cell surface characteristics specific for the carrier culture, which were lacking in uninfected Lu106 cells. In the carrier culture, there were vesiculated cells with bled-like polymorphic and ridged projections, and cells with webbed cytoplasmic extensions. Ridges and transverse striations observed on these cellular protrusions and on microvilli possibly denote oriented viral nucleocapsids at the cell membrane. Furthermore in the carrier cells, the microvilli were more heterogenous in length and diameter and were more frequently branched or fused together when compared to microvilli in uninfected cells. The results are discussed in view of the available information on the appearance of virus-infected or virus-transformed cells in the SEM, also inregard to the various factors, other than virus infection, which play a role in determining the surface features of monolayer cells.

Cell Line↗
PubMed1981

[Taxonomy-trial of the free-living amoebae belonging to the genus Acanthamoeba (Protozoa, Amoeba) by means of the cyst-features in scanning electron microscopy (author's transl)].

In order to verify the contribution of scanning electron microscopy to the taxonomic study of free-living amoebae, the authors studied at the encysted stage 21 strains of free-living amoebae representing 20 species (1 Naegleria gruberi, 1 Tetramitus rostratus and 18 Acanthamoeba sp). The method utilized is satisfactory for distinguishing the different genera. Using optical methods, it is possible to differentiate three groups (I, II, III) of Acanthamoeba, including 3, 10 and 5 species, respectively. The results obtained with scanning electron microscopy, however, are less precise. In particular, group II can be divided into only four sub-groups and group III into only two sub-groups and one species, A. culbertsoni. The method remains valid for group I.

Amoeba↗
PubMed1979

Eimeria dispersa, E. adenoeides, and E. meleagrimitis: intestinal mucosal disruption in turkeys as seen with scanning electron microscopy.

Tissues from the digestive tract of turkeys infected with Eimeria dispersa, E. adenoeides, or E. meleagrimitis were compared with tissues from uninfected controls as seen with light microscopy (LM) and scanning electron microscopy (SEM). Six regions were examined--duodenum, jejunum, ileum, cecal neck, cecal pouch, and large intestine. Although LM showed large numbers of E. dispersa in the epithelial cells, SEM usually showed little mucosal disruption. Occasionally the surface of duodenum and jejunum, as seen with SEM, was convoluted and disrupted. In one bird, some parasite-induced damage was found with either LM or SEM in the duodenum and jejunum of turkeys given E. adenoeides oocysts. Although LM showed parasites in the rest of the digestive tract of all E. adenoeides infected birds, SEM showed only a localized sloughing of the mucosa in the cecal pouch. The most extensive damage to the villar surface was caused by E. meleagrimitis. Infections often disrupted the villar tips, especially in the small intestine and cecal neck. Localized areas of pitting were often found on individual villi. All 3 species produced oocyst extrusion sites, especially in the ileum and the ceca.

Animals↗
PubMed1989

Infection of catheterised patients: bacterial colonisation of encrusted Foley catheters shown by scanning electron microscopy.

The surfaces of 32 encrusted urinary catheters were examined by scanning electron microscopy to investigate the association of bacteria with the encrusting deposits. Deposits consisted of struvite crystals surrounded by aggregates of very small crystallites of hydroxyapatite. Underneath these minerals there was a layer of closely packed bacteria. Impressions of bacteria were also observed in hydroxyapatite. Crystals were often engulfed by the bacterial layer, which thus appeared to bind the crystals to each other and to the catheter surface. This thick layer of bacteria associated with crystals may protect both the bacteria from antibiotics and the crystals from acidic bladder washout solutions intended to dissolve them. Furthermore, the existence of this sessile population explains why urease-producing bacteria are not invariably detected in the urine of patients with encrusted catheters. The observation of this bacterial layer (or "biofilm") by scanning electron microscopy provided direct evidence for infection being implicated in catheter encrustation.

Bacterial Adhesion↗
PubMedDate not supplied

An improved and simplified method for combined light and scanning electron microscopy in human urinary cytology.

Human bladder-washing and voided urine specimens from normal cases and inflammatory and malignant lesions were examined by the combined use of light microscopy (LM) and scanning electron microscopy (SEM). A newly-designed mesh, which consisted of a piece of gelatin-covered, osmium-impregnated and poly-L-lysine-coated glass slide, 0.85 mm in thickness and containing 42 compartments of 25 sq mm in size, was used in this study. This mesh permitted a direct correlation of LM and SEM images, thus shortening the time of observation of specimens under SEM. With SEM, the diagnosis of malignant exfoliated urothelial cells depended on the presence or absence of pleomorphic microvilli. The technique has enhanced the accuracy of diagnosis over conventional methods, especially for noninvasive, low-grade, papillary tumors of the urinary bladder.

Humans↗
PubMed1984

Scanning electron microscopy of experimentally induced sequential alterations of rat liver hyperplastic nodules.

Rat liver hyperplastic foci (HF) and hyperplastic nodules (HN) induced by diethylnitrosamine (DEN) according to the method of Solt and Farber were observed by light microscopy (LM) and scanning electron microscopy (SEM). Liver cirrhosis was not observed. HF, which were composed of basophilic hepatocytes arranged usually in two-cell-thick plates and occasionally one-cell-thick plates, were followed by early HN, which were composed of eosinophilic hepatocytes with enlarged nuclei and prominent nucleoli, at 4 weeks after DEN administration. SEM revealed that hepatocytes in HF had smooth surfaces and dilated bile canaliculi with a few short microvilli. Early HN (4 and 6 weeks) were composed of two-cell-thick plates of hepatocytes, whose intercellular surfaces were covered with numerous microvillous projections. Bile canaliculi were dilated and had numerous short microvilli. Late HN (6 and 8 months) were composed of eosinophilic hepatocytes, which were irregular in shape and size. Their nuclei were enlarged and nucleoli were prominent. Hepatocytes were arranged in two-cell-thick plates, but never in many-cell-thick plates. Bile canaliculi were larger than sinusoids. The bile canaliculi had numerous diverticula, but the zona occludens was present. Microvillous projections of intercellular surfaces of hepatocytes were more numerous than those of early HN. Fenestrae of the sinusoidal endothelium were lost in most parts. Kupffer cells were not seen in any stage of HN. HN progressed gradually toward hepatocellular carcinoma.

Animals↗
PubMed1984

Detection of early neoplastic changes in experimentally induced colorectal cancer using scanning electron microscopy and cell kinetic studies.

Colonic tumours were induced in Wistar rats using 12 consecutive subcutaneous injections of azoxymethane at a dose of 10 mg/kg/week. Pairs of rats were killed at five weekly intervals after initial injection until 25 weeks. Colonic mucosa was sampled from five standard areas along the length of the colon and examined by both scanning electron microscopy and conventional light microscopy. The crypt cell production rate was measured by stathmokinetic techniques. Scanning electron microscopy showed microadenomas as early as five weeks and consistently after 15 weeks. They were found predominantly in the distal colon and increased in size with time. The lesions showed a progressive increase in the number of crypts per adenoma and increasingly disorganised slit shaped crypt orifices. The presence of epithelial dysplasia in the microadenomas and of invasion of the colonic wall by carcinoma was confirmed histologically, although fewer lesions were identified in tissue sections than by scanning electron microscopy. Crypt cell production rate increased with time, particularly in the distal colon. This increase was significant between five and 25 weeks. The results of these observations suggest that there is an adenoma-carcinoma sequence in this animal model. The value of scanning electron microscopy in identifying and quantifying the mucosal changes during carcinogenesis is emphasised.

Adenoma↗
PubMedDate not supplied

Scanning electron microscopy and profilometer evaluation of glazed and polished dental porcelain.

The surface roughness of Vita VMK porcelain following oven glazing and eight grinding/polishing treatments was analyzed qualitatively using scanning electron microscopy and quantitatively using a profilometer. Techniques were selected to simulate clinical practice. Scanning electron microscopy evaluation found oven glazing produced a better surface than other polishing methods. On the basis of the profilometric examination, the best roughness average value was obtained using diamond instruments with progressively smaller particle sizes (30, 15, and 8 microns). Scanning electron microscopy analysis showed that all the treatments left the surfaces partially porous and cracked; however, the glazed surface yielded the best result. Although no significant differences were detected for the different treatments, the use of a 30-microns diamond instrument produced a rougher surface. No correlation was found between scanning electron microscopy and profilometer results. This study suggests that several procedures may be used to effectively finish ceramic surfaces.

Analysis of Variance↗
PubMedDate not supplied

Scanning electron microscopy substantiates histology in showing the inadequacy of the existing theories on the development of the proximal coronary arteries and their connections with the arterial trunks.

Development of proximal coronary arterial segments and coronary arterial orifices was studied by scanning electron microscopy in 20 rat embryos and by light microscopy in serial sections of 20 human and another 18 rat embryos. Neither by scanning electron microscopy nor by light microscopy did we observe more than two coronary arterial orifices. These coronary orifices were always situated in the sinuses of the aorta that faced the pulmonary artery. In the human embryos the coronary orifices emerged between 37-39 days of gestation (16-19 mm crown-rump length, Streeter horizon XVIII-XIX) and were invariably present beyond 39 days (19 mm crown-rump length, Streeter horizon XIX). In rat embryos, the coronary orifices emerged in both scanning electron microscopy and light microscopy at 15-17 days of gestation (13-17 mm crown-rump length) and were invariably present beyond 17 days (17 mm crown-rump length). In both human and rat embryos, either by scanning electron microscopy and light microscopy, the left coronary orifice was observed significantly earlier. In all the investigated embryos, human as well as rat, septation at arterial orifice level was complete, including the earliest stages studied. Light microscopy showed that at the emerging stages of the coronary orifices, the proximal epicardial segments of the left and right coronary arteries could already be identified in a peritruncal ring of epicardial vasculature, before the coronary orifice was observed. This was the case in human as well as in rat embryos. Thus, a coronary orifice was never seen in the absence of a proximal coronary artery. The present theories on development of the proximal coronary arteries and coronary orifices do not offer an adequate explanation for either these data or the known possible congenital abnormalities of the coronary arteries. Our study supports dual proximal coronary arterial development. These two proximal coronary arteries develop out of a peritruncal ring of vascular structures on to the aorta. The process by which the coronary orifices actually develop remains to be explained.

Animals↗