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PubMed2001

[Study of the root nodules in some species of the Papilionaceae subfamily by scanning electron microscopy].

Nitrogen-fixing nodules from 16 species in 6 tribes of the sub-family Papilionaceae have been examined by scanning electron microscopy. The structure of infection threads was similar in all the studied papilionoid species except Lupinus polyphillus. In this species the infection threads were found in young nodules only. The morphology of bacterioids and the character of their "package" are determined by the host plant genotype. The obtained results are discussed in relation to the evolution of the legumes.

Fabaceae↗
PubMed1992

Scanning electron microscopy of the rabbit gallbladder mucosal microvasculature.

The arrangement of the microvasculature of the rabbit gallbladder was studied by means of scanning electron microscopy (SEM) of vascular corrosion casts and parallel uncorroded samples, together with correlated light microscopy (LM) observations. The outer layers of the gallbladder wall possess a coarse capillary network supplied by long and straight vessels which also give off numerous smaller twigs for the mucosal layer. Thin richly branched and anastomosing capillaries originate from the mucosal twigs. The mucosal capillaries are arranged in structures having a bowl-like configuration with the convexity facing towards the serosal layer, and the concavity corresponding to the epithelial lacunae seen by SEM of uncorroded samples. These structures were polygonal or irregularly rounded, and limited by vessels arranged in folds. The vessels running in these folds were capillaries and/or venules. The vascular folds corresponded to the epithelial folds demonstrated by SEM and LM of uncorroded samples.

Animals↗
PubMed1992

Preserving the original architecture of elastin components in the formic acid-digested aorta by an alternative procedure for scanning electron microscopy.

The present study examined procedures of specimen preparation for observing elastin components in the formic acid-digested tissue by scanning electron microscopy (SEM). The rat thoracic aorta fixed in 4% paraformaldehyde was treated with 90% formic acid for 85-96 hr at 45 degrees C and processed in two different ways: 1) the tissues were freeze-dried directly from water and 2) they were treated with tannic acid and osmium followed by critical point drying. The former procedure caused marked deformation of elastin components, while the latter preserved them well in shape and arrangement. Thus, the three-dimensional organization and ultrastructure of the elastin components were precisely demonstrated in this study.

Animals↗
PubMed1977

Identification of microcrystals in synovial fluids by combined scanning electron microscopy and x-ray diffraction : application to triclinic calcium pyrophosphate dihydrate.

We report a method for studying microcrystals which combines scanning electron microscopy, electron-dispersive X-ray analysis, and X-ray diffraction. Application of all three techniques to the same crystalline bodies permits correlation of their three-dimensional morphology at high magnification with unambiguous identification by means of their crystallographic properties. The method was applied to triclinic calcium pyrophosphate dihydrate.

Calcium Pyrophosphate↗
PubMed1983

Studies on corneal endothelial growth and repair. IV. Changes in the surface during cell division as revealed by scanning electron microscopy.

Changes in the surface morphology of regenerating rabbit, rat and frog corneal endothelial cells in vivo have been investigated by scanning electron microscopy. In adult tissue these cells do not normally divide unless given a stimulus, such as injury. Surfaces of quiescent rabbit and rat cells are devoid of microvilli but display globular projections and surface pits up to 300 nm in diameter. However, regenerating endothelia are characterized by the appearance of microvilli which attain their greatest length when the cells are rounded. At this stage, cells also possess filopodia and broad processes. In cytokinesis, the microvilli have shortened and blebs and ruffles appear for the first time. In contrast to rabbits and rats, frog endothelial cells of noninjured tissue are covered by microvilli and smaller surface pits of 60-70 nm diameters. During regeneration, these cells have reduced numbers of microvilli and extensive foldings of the membrane. Neither blebs nor filopodia occur during the mitotic cycle and ruffles are not detected until cytokinesis.

Animals↗
PubMedDate not supplied

Studies on T and B lymphocytes by the technique of immune and non-immune rosettes and by scanning electron microscopy (SEM) in Graves' disease and nontoxic nodular goiter.

T and B lymphocytes were studied by the rosettes technique (R) and scanning electron microscopy (SEM). Both techniques showed pathogenic changes in Graves' disease and nontoxic nodular goiter patients. In normal subjects, the mean value for T lymphocytes was 63.8% by R and 62.9% by SEM and for B lymphocytes was 39.9% by R and 29.8% by SEM. In Graves' disease the mean value of T lymphocytes was 93.1% by R and 92.8% by SEM whereas B lymphocytes represented 6.6% by R and 11.5% by SEM. In nontoxic nodular goiter, the mean T lymphocytes count was 64.5% by R and 61.5% by SEM, whereas B lymphocytes represented 27.9% by R and 29% by SEM. The increase in T lymphocytes number in Graves' disease confirms the role of cell immunity in its pathogeny unlike nontoxic nodular goiter where this mechanism has not been confirmed.

Adult↗
PubMed1982

[Scanning electron microscopy of the normal and carious aprismatic enamel surface of human temporary teeth].

The study of human primary teeth surfaces by scanning electron microscopy has shown that the localization and the extent of the aprismatic surface layer although present in all teeth studied was quite variable from one tooth to an other. Such an aprismatic layer could be found along the molar fissures. However each tooth studied possessed an important surface layer consisting of prismatic enamel. The respective distribution of prismatic and aprismatic enamel layers was highly variable and can hardly by systematized. The study of apparently intact layers of incipient carious white spot lesions has shown that the irregular type of surface destruction was related to the presence of an aprismatic enamel surface layer.

Child↗
PubMed1982

Scanning electron microscopy of isolated dog renal tubules.

Isolation of canine renal tubular segments, cell clusters and individual cells permits direct observation by scanning electron microscopy (SEM) of the three dimensional cell shapes and the complex lateral and basal labyrinth structures. These functionally vital areas of the various tubular segments have not been previously observed in such detail. The tubular segments were freed of the obscuring basement membranes by prolonged tryptic digestion of tissue perfusion-fixed with glutaraldehyde, followed by attachment to gelatine coated coverslips and preparation for SEM. The tubular basal labyrinth is found to consist of a mosaic of basal processes arising from the lateral processes and the base of the cell body. The lateral processes and basal processes interdigitate with adjacent cells. Each tubular segment exhibits its own characteristic patterns of basal processes. The basal processes of the proximal convoluted tubule (PCT) are shaped like an inverted anvil, often branching. The basal processes of the proximal straight tubule (PST) and thin limbs are short microvilli. The distal straight tubule (DST) have fishtail-like basal processes. The distal convoluted tubule (DCT) show a swirling mixture of anvil shaped and microvillous basal processes. The collecting ducts exhibit short basal microvilli, plicae and villi lined basal infoldings. The looser structure of the basal labyrinth of cell clusters and isolated cells produced by this isolation procedure facilitated recognition of these complex structures.

Animals↗
PubMedDate not supplied

[Scanning electron microscopy (SEM) and microanalysis (EDS) applied to the study of biomaterials for dental use. 6].

The study considers the use of scanning electron microscopy (SEM) and EDS microanalysis applied to the study of numerous mineral-based biomaterials of common use in odontostomatology. The products studied are the following: reabsorbable Dac Blu, non reabsorbable Dac Blu, non reabsorbable atomized Dac Blu, non rabsorbable fine Dac Blu, reabsorbable Biocoral 450, Calcitite 2040-12, Orthogel, Apagen, BTF 65, Calcitite 4060-2, Osprogel, Bio-Oss, Biostite, Ospro-vit, Merck Hydroxyapatite. By means of SEM it was possible to study the morphology and the microchemistry of the various biomaterials so as to have information about their physical and chemical characteristics, such as the crystalline form, the crystalline aggregations, the space dimensional distribution of the pores and check the possibilities of composition variability. All of these factors are fundamental to evaluate the functional biocompatibility of a biomaterial, once that its performance in a biological environment is known.

Biocompatible Materials↗
PubMed1994

Scanning electron microscopy of the wild boar and pig lingual papillae.

Lingual papillae of wild boar and pig were studied by means of scanning electron microscopy (SEM). Vallate papillae appear with the typical circumvallate morphology. Their papillary bodies show conical or fungiform-like and spicule-like pseudopapillae in both animals. Taste pores were seen in the papillary grooves. Microplicae or pits are visible at high magnification. In pig and wild boar similar foliate papillae were observed. Pig has less but wider leaves than wild boar. Taste pores on papillary walls were viewed. At high magnification microplicae were seen. Morphologically, fungiform papillae correspond with their denomination. Taste pores open onto the upper surface and they are easily identifiable by SEM. The rostral and lateral regions contain the major number of fungiform papillae. The lateral papillae of wild boar and pig show a high number of pores per papilla. These regions must be considered important in taste sensitivity. Lateral papillae in both animals could provide a source of taste buds for study. In both animals the fungiform papillary epithelium showed a pitted appearance as a consequence of keratinization by food environmental stress. The filiform papillae can be both simple and compound (with body and hairs). Large conical papillae are located caudally and curved in the same direction. Filiform and conical papillae have a function in food mastication, handling and deglutition.

Animals↗
PubMedDate not supplied

Detection of calcifications in breast biopsies by scanning electron microscopy.

The identification of microcalcifications in breast biopsy specimens is a common and important task for the surgical pathologist that may sometimes be problematic. Although visualized by preoperative mammographic and operative specimen radiography, some cases may fail to reveal calcifications by histopathologic examination or occasion laborious and time-consuming study to confirm sparse calcifications. The present study demonstrates how conventional bright-field and polariscopic light microscopy did require considerable effort to confirm rare calcification. On the other hand, scanning electron microscopy was employed directly on a routine slide and provided definitive visual and physical proof, e.g., by means of energy dispersive x-ray microanalysis of a rare calcification on a slide previously judged to be negative for calcium and in a short period of time. Recent instrument advances in high voltage beam stabilization and in the ability to vary the pressure of the scanning electron microscope in the vicinity of the specimen now allow complete insertion of a diagnostic glass slide with only trivial preparation. The report, although brief, raises important questions regarding the extent and prevalence of breast calcifications.

Adult↗
PubMedDate not supplied

[Scanning electronic microscopy of the small intestine in persistent diarrhea].

Persistent diarrhea very often leads children to malnutrition. It has become the major cause of death resulting from acute diarrhea episodes in developing countries. In order to determine the ultrastructural alterations of the small bowel that occur in the syndrome, 16 infants with severe persistent diarrhea were studied, utilizing light microscopy and the scanning electron microscope. Stool and jejunal fluid samples were collected for culture, rotavirus, ova and parasite search. Enteropathogenic agents were isolated in stools from 11 (68.7%) patients and bacterial proliferation in the small bowel was detected in 11 (68.7%) patients. EPEC strains were the most frequent enteropathogenic agent isolated both from stool and jejunal fluid cultures. The stool cultures revealed the presence of the following enteropathogenic microorganisms: EPEC 0111 in four, EPEC 0119 in one, EAggEC in five, Shigella flexneri in two, and Shigella sonnei in one; mixed infections due to EAggEC associated with EPEC 0111 were seen in two patients. The light microscopic analysis revealed that 56.2% of the patients suffered moderate villous atrophy most frequently associated with effacement of the microvilli, intracytoplasmatic vacuolization, increased number of multivesicular bodied and increased lymphocytic and eosinophylic infiltration in the lamina propria. The scanning electron microscopic analysis revealed in all cases shortening of the villi and enterocyte derangements; very often there was a total lack and/or effacement of the microvilli; in half of the patients there was a mucoid material covering the enterocytes tightly adhered to the apical epithelium surface. The scanning ultrastructural alterations observed in these patients are probably due to an association of factors brought about by the presence of enteropathogenic microorganisms and the resulting food intolerance that is responsible for perpetuation of diarrhea.

Diarrhea, Infantile↗
PubMed1996

Problems in preparation of chromosomes for scanning electron microscopy to reveal morphology and to permit immunocytochemistry of sensitive antigens.

Although much information about chromosome structure and behaviour has been obtained using light microscopy, greater resolution is needed for a thorough understanding of chromosome organisation. Scanning electron microscopy (SEM) can provide valuable data about these three-dimensional organelles. The introduction of methods using osmium impregnation of methanol-acetic acid-fixed chromosome spreads revolutionised matters, producing life-like images of chromosomes. Nevertheless, it became clear that osmium impregnation introduced various artefacts, although the resulting images were still useful. Methanol-acetic acid-fixed chromosomes are, in fact, flattened on the glass substratum, and the 3-dimensional appearance obtained after osmium impregnation is the result of swelling during this process. At the same time, the fibrous substructure of the chromosomes becomes much coarser. More recently a number of alternative methods have become available for studying chromosomes by SEM. Isolated chromosomes, that have not been allowed to dry during preparation, retain a 3-dimensional appearance without osmium impregnation, and the same is true of methanol-acetic acid-fixed chromosomes that have been treated with 45% acetic acid and processed without drying; however, these methods do not permit the routine production of intact metaphase spreads. Use of cytocentrifuge preparations obviates the use of acetic acid fixation and osmium impregnation, produces intact metaphase spreads, and permits the immunocytochemical detection of antigens that are easily destroyed by routine fixation procedures.

Acetic Acid↗
PubMed1977

Effect of pretreatment with ethanol containing fluoride on etched enamel surface as evaluated by scanning electron microscopy, optical microscopy, and tensile bond strength measurement.

The effects of pretreatment with a fluoride-containing ethanol solution on etched enamel surfaces before application of sealant were examined using scanning electron microscopy, optical microscopy, and tensile bond strength determinations. The results suggested that when etched enamel surfaces are treated with ethanol containing no more than 250 ppm fluorine in potassium fluoride, there is no interference with the bonding of the sealant to the treated, etched anamel surface.

Acid Etching, Dental↗
PubMed2001

Scanning electron microscopy determination of string mozzarella cheese in gastric contents.

As part of a suspected homicide investigation, a sampling of the gastric contents from the victim was forwarded to the U.S. Food and Drug Administration's Forensic Chemistry Center (FCC) for analysis of specific, selected components. The victim was known to have consumed string mozzarella cheese, as a snack, less than 24 h before his disappearance and the subsequent discovery of the body. The investigation sought to confirm or dismiss speculation the victim may have been fed a meal or eaten additional food prior to his death. Analysis of the stomach contents involved examination by stereoscopic light microscopy (SLM) and isolation, processing, and analysis of suspect materials by scanning electron microscopy (SEM). Several wax-like, off-white to cream-colored objects were noted by SLM examination and removed from the gastric contents. Through a series of fixation, sectioning, drying, and coating steps, these objects were prepared for analysis by SEM. Comparison of the suspect material with laboratory control string mozzarella cheese showed excellent correlation between the analyzed samples, confirming the suspect material from the stomach contents as string mozzarella cheese.

Cheese↗
PubMed1989

Scanning electron microscopy and gel electrophoresis of vascularized periosteal autografts.

This study was devised to investigate the morphologic and biochemical sequence of events occurring during early periosteal osteogenesis in vascularized periosteal flaps. A pleuroperiosteal flap based on the intercostal vessels was developed and rotated onto the chest wall in 12 adult dogs. Animals were sacrificed at intervals between 7 and 60 days, and the flaps were removed with the underlying muscular bed. Specimens were studied by tetracycline uptake, gel electrophoresis, light microscopy, and the scanning electron microscope. Osteoprogenitor cells were seen as early as 7 days after transfer. Collagen fiber deposition was vigorous and noted in all specimens with rapid mineralization by 9 to 15 days. There was no structural or vascular interaction between the flaps and the recipient muscular bed. Gel electrophoresis confirmed the presence of type I and III collagen, with an increase in type I collagen over time. The pattern of collagen deposition and the final bony architecture resembled that of woven bone.

Animals↗
PubMedDate not supplied

Comparison in spatial spreads of secondary electron information between scanning ion and scanning electron microscopy.

Monte Carlo simulations have been carried out to compare the spatial spreads of secondary electron (SE) information in scanning ion microscopy (SIM) with scanning electron microscopy (SEM). Under Ga ion impacts, the SEs are excited by three kinds of collision-partners, that is, projectile ion, recoiled target atom, and target electron. The latter two partners dominantly contribute to the total SE yield gamma for the materials of low atomic number Z2. For the materials of high Z2, on the other hand, the projectile ions dominantly contribute to gamma. These Z2 dependencies generally cause the gamma yield to decrease with an increasing Z2, in contrast with the SE yield delta under electron impacts. Most of the SEs are produced in the surface layer of about 5lambda in depth (lambda: the mean free path of SEs), as they are independent of the incident probe. Under 30 keV Ga ion impacts, the spatial spread of SE information is roughly as small as 10 nm, decreasing with an increasing Z2. Under 10 keV electron impacts, the SEI excited by the primary electrons has a small spatial spread of about 5lambda, but the SEII excited by the backscattered electrons has a large one of several 10 to several 100 nanometers, decreasing with an increasing Z2. The main cause of a small spread of SE information at ion impact is the short ranges of the projectile ions returning to the surface to escape as backscattered ions, the recoiled target atoms, and the target electrons in collision cascade. The 30 keV Ga-SIM imaging is better than the 10 keV SEM imaging in spatial resolution for the structure/material measurements. Here, zero-size probes are assumed.

Journal Article↗