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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↗

PubMed1977

Comparison of cancer cell surfaces of the lower reproductive tract by scanning electron microscopy.

The squamous cells of the cervix simulate those of the vagina and vulva both histologically and by scanning electron microscopy. However, in areas of the cervix undergoing active metaplasia, there are cells which share some of the characteristics demonstrated by scanning electron microscopy of both squamous and columnar epithelium. In these cells there is a wide range of characteristics of each cell type, suggesting a possible gradual transition from columnar to squamous epithelium. Furthermore, the cells of severe dysplasia and of intraepithelial and invasive squamous cancers of the cervix, though histologically similar to those of vaginal and vulvar cancers, are distinctly different when examined by scanning electron microscopy. These findings suggest that both metaplastic and neoplastic squamous cells are derived from the same progenitor columnar cells of the cervix, by orderly transition in the former and by atypical transformation in the latter. Second, the distinctiveness from the vaginal and vulvar cells indicates different embryonic stem cell lines.

Carcinoma in Situ↗

PubMed1993

Scanning electron microscopy study of articular cartilage in the evolution of hip arthritis.

The authors report the results of scanning electron microscopy examination of samples of articular surface taken from 15 arthritic femoral heads removed during hip replacement. The specimens were collected from areas of the femoral head where different degrees of degenerative changes were identified, and processed with the normal techniques for scanning electron microscopy. A definition was made of the mechanisms leading to articular cartilage wear, the most obvious sign of cartilage degeneration. The earlier stages were characterized by the appearance of clefts in the surface layer, which merged and formed scales that flaked off, giving rise to superficial abrasions. The evolution of the degenerative process led to a deepening of the clefts, reaching the intermediate and deep layers and creating further scales of cartilage tissue, oblique or perpendicular to the surface. The elimination of these formations causes more or less marked wear that can extend down to the subchondral bone (ulcers and ground surfaces). As well as information on the condition of the articular surfaces, scanning electron microscopy may also provide details on the morphology and structure of the chondrocytes and the fibrillar network in the sagittal sections, showing the regressive phenomena associated with arthritis.

Aged↗

PubMed1976

Light and scanning electron microscopy of exfoliated bladder epithelial cells in rats fed N-(4-(5-nitro-2-furyl)-2-thiazolyl)formamide.

Urine specimens obtained periodically from weanling male F344 rats fed 0.2% N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) for 25 weeks followed by control diet for an additional 35 weeks, were examined by light microscopy (LM) and scanning electron microscopy (SEM). LM revealed red blood cells and atypical transitional cells in the urine at 25 and 43 weeks, when microinvasive transitional cell carcinoma was present. Malignant transitional cells were seen in the urine by LM at 60 weeks, when muscle invasion was present in histologic sections. However, SEM showed pleomorphic microvilli on exfoliated urothelial cells as early as 10 weeks after the beginning of FANFT administration, and the microvilli became increasingly pleomorphic as the bladder lesions progressed to muscle invasion at 60 weeks. Noninvasive tumors were present in histologic sections of rat bladders examined at the end of 10 weeks of FANFT administration. The numerous microvilli on exfoliated bladder tumor cells were in sharp contrast to the peaked microridges of normal exfoliated superficial cells.

Animals↗

PubMed1988

A survey by scanning electron microscopy of the extracellular matrix and endothelial components of the primordial chick heart.

Scanning electron microscopy was used to study the morphogenesis of the primitive embryonic chick heart (stage 5 late primitive streak through stage 9+). Components of the developing heart (myocardium, endocardial endothelium, and extracellular matrix) were viewed from the ventral surface after removal of the endoderm. The myocardial component of the heart can first be seen by light microscopy at stage 5 as two darker oval-shaped areas located on either side of the embryonic axis in the cranial region of the embryo. Scanning electron microscopy demonstrates that as early as stage 6 an area of extracellular matrix, enriched in comparison to more lateral and medial splanchnic mesoderm, can be identified ventral to the myocardial primordium. As heart formation progressed we observed primordial endothelial elements in the splanchnic mesoderm lateral to the myocardial primordia. By late stage 7 these lateral primordial elements had anastomosed into small, loose plexuses. This process of anastomosis progressed rapidly, and by stage 8 the entire cranial surface of the myocardial primordium was covered with vascular plexuses. By late stage 8 the progressive fusion of these plexuses resulted in the formation of large multiple tubular elements near the midline. More medially the fusion of tubular elements resulted in a continuous endothelial sheet at the midline.

Animals↗

PubMed1980

Scanning electron microscopy of brain ventricular surfaces: a bibliography.

This bibliography is designed to facilitate the rapid identification and location of references concerning the application of scanning electron microscopy to investigations of the cerebroventricular system and related cerebrospinal fluid contacting surfaces. Because SEM provides information regarding cell surfaces, it is admirably suited to the examination of the brain ventricular system since the morphology of the CSF interface is of the utmost importance in accomplishing the diverse functions of the ependyma and associated circumventricular organs. The bibliography attests to the fact that scanning electron microscopy has provided a major impetus to the study of the structure and function of the circumventricular organs, choroid plexuses and tanycytic ependyma as well as the distribution and morphology of such supraependymal cellular elements as macrophages, neurons, and neuronal proceses. Furthermore, not only are SEM methodologies being applied to an ever lengthening list of phyla and species, but the diversity of problems amenable to the profitable application of scanning electron microscopy also is rapidly increasing. Investigations to date, for example, include studies of ventricular morphology during development and maturity, health and disease, and prior to as well as following experimental manipulation. While remarkable strides have been made toward a greater understanding of many aspects of cerebroventricula structrure and function, many significant problems clearly await the judicious application of scanning electron microscopy.

Bibliographies as Topic↗

PubMed1981

Scanning electron microscopy, autolysis, and irradiation as techniques for studying small intestinal morphology.

Examination of autolysed control mouse small intestine using scanning electron microscopy has revealed details of the connective tissue components of the mucosa. The cores of the villi are seen collapsed across the intervillous basin. Crypts of Lieberkuhn are seen as tubular channels stretching down from the intervillous basin. Sometimes the crypts are split in two by a connective tissue septum. The mouths of the crypts of Lieberkuhn are, in general, arranged in double rows between the single rows of villi. The ratio of number of crypts to numbers of villi was calculated as 5.01:1. This is close to the figure of 4.53:1, as quoted by Smith & Jarvis (1980) who used differential interference contrast microscopy to investigate the crypt to villus ratio. After radiation, the severe drop in the number of crypt mouths can be clearly seen by the combination of autolysis and scanning electron microscopy: the rows of crypt mouths between the villi have been lost, and many crypt mouths have been occluded by stromal tissue. The arrangement of the crypt mouths and the observation of mucosal abnormalities after irradiation have led to the postulation that cells leaving the crypt mouths move in a spiral manner towards and then up the villous surface: this postulated movement might imply an asymmetry in some properties of enterocytes. The use of scanning electron microscopy in conjugation with autolysis and irradiation has thus forced a critical re-examination of the relationships between crypts and villi.

Animals↗

PubMed1985

Scanning electron microscopy of the human myocardium.

Owing to the impossibility of fixation, in the human being, by means of perfusion in vivo and the rare availability of fresh comparatively intact hearts resected at transplantation, the possibility was explored of using post-mortem material in instances where the autopsies were performed within 2 hours of demise of the patients. Four cases were examined: 2 normal adult hearts and 2 hearts of hypertensive patients in the stage of decompensation. The hearts were fixed by means of perfusion with 2.5% glutaraldehyde in phosphate buffer, pH 7.4. Contiguous blocks were taken for light microscopy (LM) and scanning electron microscopy (SEM) from the left ventricular free wall of all 4 cases and of the impulse conducting system of the heart in the 2 normal hearts. The SEM material was processed by the osmium-thiocarbohydrazide-osmium method (O-T-O). There was good correlation between the LM and SEM findings. The left ventricular blocks were sectioned in the transverse axis and SEM showed a step-wise transection of the myofibrils. Z and M bands, mitochondria and myofilaments were identified a ultrastructural magnifications. The difference in vascularity between normal and hypertensive myocardium and the presence of para-arterial fibrosis in the latter were demonstrated by SEM. The SEM study of the impulse conducting system of the heart included the sinoatrial (SA) and atrioventricular (AV) nodes and the penetrating portion of the atrioventricular (AV) bundle of His. Characteristic pacemaker or "P" cells were identified in the nodes.

Adult↗

PubMed2005

A new method for isolation of leukocytes from the peripheral blood of amphibians [Bufo himalayanus, (Gunther)] and study of their surface morphology by scanning electron microscopy.

Using percoll as the density gradient, a new single step method to isolate leukocytes from the peripheral blood of amphibians (B. himalayanus) has been described. Isolated leukocytes were photographed under the scanning electron microscope and an attempt has been made to characterize the leukocyte population on the basis of surface morphology. Apart from regular blood cell types, B. himalayanus have slender, elongated and slightly curved leukocyte type cells in their peripheral blood. Such slender elongated cells were absent in the blood of a related species B. stomnaticus and hence could not be categorized under the known blood cell types.

Animals↗

PubMed1997

[Interaction of silicone oil with various intraocular lenses. A light and scanning electron microscopy study].

BACKGROUND: Silicone oil is increasingly used as an intravitreal tamponade in severe forms of vitreoretinal disorders, also in pseudophakic eyes. In some patients silicone oil was observed to be adherent to the intraocular implant. MATERIAL AND METHODS: To investigate the interaction of silicone oil with IOL-materials and the influence of lipoproteins of the serum on this interaction we used the following in vitro experimental set-up: Sterile IOLs of different IOL-materials (e.g. PMMA, silicone, hydrogel) and surface-modifications (e.g. Pharmacia 809P and 809C, Soflex LI41U, Alcon AcrySof M60BM, Allergan SI-30NB, SI-40NB, Chiron adatomed 90D, C10 and C31UB, MemoryLens U940A, Corneal ISHEMA 66, Storz H60M) were stored in vitro together with silicone oil (1000 centistokes) with and without a fresh serum solution at 37 degrees Celsius. This combination was rotated slowly and mixed thoroughly three times a day. After 3 and 6 months and a standardized special preparation in an ultrasound bath and air treatment, the IOLs were examined by light microscopy followed by scanning electron microscopy. RESULTS: Silicone oil strongly adhered to holes and to the IOL surface especially in silicone and PMMA IOLs. Highly hydrophylic IOLs-like the heparin-surface-modified and hydrogel IOL-cleared from silicone oil relatively early. This effect was more pronounced in the group with lipid-/serum solution than without. In some silicone IOLs silicone oil was strongly adherent to the lens and it was nearly impossible to wash off the oil even when using an alcoholic solution. One silicone IOL lost its haptics in the serum-oil-IOL-mixture, another lost small particles from the IOL surface. CONCLUSION: Silicone oil is more adherent to hydrophobic IOLs than to hydrophylic IOLs. Lipoproteins of the serum play an important role in facilitating an effect of silicone oil on IOL materials. We recommend highly hydrophylic especially surface-modified IOLs for lens implantation following vitreoretinal silicone oil surgery. Implantation of silicone IOLs in vitreoretinal high risk eyes should be avoided.

Equipment Failure Analysis↗

PubMed1988

Scanning electron microscopy of vertebrate cerebellar cortex.

In this study, the Golgi method for light microscopy, transmission and conventional scanning electron microscopy, the ethanol-cryofracturing technique, the freeze-fracture method for SEM, and the freeze-etching method have been used in conjuction to analyze the three-dimensional cytoarchitectonic arrangement and intracortical circuits of vertebrate cerebellar cortex. Approximately more than 100 specimens of mice, rat, teleost fishes and human cerebelli were processed by the above mentioned techniques. A chronological review of other methods for studying hidden surfaces of cerebellar nerve cell has been also described. The three-dimensional morphology, outer and inner surfaces of granule, Golgi, Purkinje and stellate cells were reviewed by means of a correlative and comparative study. The cerebellar circuits formed by mossy and climbing fibers with granule cell dendrites and Purkinje cell-granule cell synapses have been traced by ethanol-cryofracturing technique, freeze-fracture method for SEM and freeze-etching technique. These findings have been correlated with previous light and electron microscope findings published in the last century. Some advantages and limitations of each method are pointed out. The review emphasizes the paramount importance of correlating light microscope Golgi method with ethanol-cryofracturing and slicing techniques for SEM. The correlation between freeze-fracture method for SEM and freeze-etching technique provides a new approach for studying three-dimensional morphology of nerve cells at cellular and macromolecular levels. This modern methodology of three-dimensional analysis offers new potential areas for future experimental investigation in embryology and pathology of the central nervous system.

Animals↗

PubMed1986

Scanning electron microscopy of Barrett's epithelium and its correlation with light microscopy and mucin stains.

The surface epithelial cells of Barrett's esophagus were characterized using quantitative scanning electron microscopy and light microscopy with mucin histochemical stains. Fifty-one biopsy specimens of Barrett's esophagus from 15 patients and 31 control specimens of the stomach and intestines from 9 patients were examined. Three distinct surface cell types, in addition to the goblet cell, were recognized in Barrett's epithelium: the gastric-like cell in 31% of specimens, which was similar to the normal gastric surface cell by quantitative scanning electron microscopy; the intestinal-like cell in 41%, which was most similar to the normal small intestinal surface cell; and the variant cell in 80%, which had a range of surface features. By light microscopy, all specimens with variant and intestinal-like cells were classified as specialized columnar epithelium. The surface mucous cells in Barrett's epithelium displayed a variety of mucin staining patterns with acid nonsulfated (small intestinal-like) mucin present in 90% of specimens and acid sulfated (colonic-like) mucin in 43% of specimens. Quantitative scanning electron microscopy and mucin histochemical stains reveal a striking cellular heterogeneity not apparent by routine light microscopy.

Barrett Esophagus↗

PubMed1975

New immunolatex spheres: visual markers of antigens on lymphocytes for scanning electron microscopy.

New immunochemical reagents consisting of antibodies bound to small latex spheres were used as visual markers for the detection and localization of cell surface antigens by scanning electron microscopy. Cross-linked latex spheres of various sizes from 300 to 3,4000 A in diameter were synthesized by aqueous emulsion copolymerization of methacrylate derivatives containing hydroxyl and carboxyl functional groups. Proteins and other molecules containing primary amino groups were covalently bonded to the acrylic spheres under a variety of mild conditions by the aqueous carbodiimide, cyanogen bromide, and glutaraldehyde methods. For use in the indirect immunochemical-labeling technique, goat antibodies directed against rabbit immunoglobulins were bonded to the spheres. These immunolatex reagents were shown to bind only to cells (red blood and lymphocytes) which had previously been sensitized with rabbit antibodies against cell surface antigens. Mouse spleen lymphocytes with exposed immunoglobulins on their surface (B cells) were labeled with these spheres and distinguished from unlabeled or T lymphocytes by scanning electron microscopy. The distribution of Ig receptors on lymphocytes was also studied using the spheres as visual markers. When lymphocytes were fixed with glutaraldehyde and subsequently labeled with the immunolatex reagents, a random distribution was observed by scanning electron microscopy; a patchy distribution was observed when unfixed lymphocytes were used. These results are consistent with studies using ferritin-labeled antibodies (S. De Petris and M. Raff. 1973. Nature [Lond.]. 241:257.) and support the view that Ig receptors on lymphocytes undergo translational diffusion. In addition to serving as visual markers for scanning electron microscopy, these latex spheres tagged with fluorescent or radioactive molecules have applications as highly sensitive markers for fluorescent microscopy and as reagents for quantitative studies of cell surface antigens and other receptors.

Animals↗

PubMed1982

Scanning electron microscopy of Giemsa-stained chromosomes and surface-spread chromosomes.

Giemsa-stained chromosomes as prepared for light microscopy, and including G-banded, C-banded, and FPG-stained chromosomes, were examined by scanning electron microscopy. Although suitable for light microscopy, these chromosomes were too flat for a close examination of their fine structure by scanning electron microscopy. The surface of Giemsa-positive regions was rough and bright, whereas that of unstained or poorly stained regions was smoother and less bright. Giemsa-staining, therefore, seems to produce the bulkiness of the chromosomes. On topographical examination by scanning electron microscopy, the transparent chromosomes as observed with the light microscope proved to be "footprints". Stereographical examinations of surface-spread chromosomes showed that minimally stretched chromosomes were composed of a mass of nodular and twisted looping fibers with an average diameter of about 300 A. The substructure of these chromosome fibers was not determined. The kinetochore region was discernible as a constriction in the mass of the chromosome fibers, and was distinguishable from gaps by the presence of several chromosome fibers parallel to the axis of the chromatid. The organization of the chromosome fibers, however, was disordered rather than regular.

Azure Stains↗

PubMed1995

Scanning electron microscopy of the human esophagus: application to Barrett's esophagus, a precancerous lesion.

In Barrett's esophagus, metaplastic columnar epithelium replaces the normal squamous epithelium. The importance of this lesion lies in the increased incidence of adenocarcinoma of the esophagus occurring in patients with Barrett's esophagus. We characterized the surface epithelial cells of Barrett's esophagus using quantitative scanning electron microscopy. Three distinct surface cell types, in addition to the globlet cell, were recognized in Barrett's epithelium: the gastric-like cell and the intestinal-like cell, both of which were similar to normal gastric and small intestinal surface cells, respectively, by quantitative scanning electron microscopy, and the variant cell which had a range of surface features. In four biopsy specimens from the squamo-Barrett's junction in three patients, we found the distinctive cell that had features intermediate between those of squamous and columnar epithelium. On the distinctive cell's surface there are two disparate structures not normally present on the same cell in the gastrointestinal tract: microvilli (a scanning electron microscopy feature of glandular epithelium) and intercellular ridges (a scanning electron microscopy feature of squamous epithelium). The surface characteristics of this cell were almost identical to those of cells found in the transformation zone of the uterine cervix, an area in which squamous epithelium physiologically replaces columnar epithelium. Scanning electron microscopy of Barrett's esophagus has increased our understanding of this precancerous lesion by showing striking cellular heterogeneity. It has also identified the distinctive cell which may represent an intermediate step in the development of Barrett's epithelium during which the surface characteristics of two different cell types, columnar and squamous, coexist in the same cell.

Barrett Esophagus↗

PubMed1995

Section directed cryosectioning of specimens for scanning electron microscopy: a new method to study cardiac development.

A new method to study the developing heart was developed. Using this "section directed" cryosectioning method, appropriate fixed embryos can be trimmed optimally to obtain sectional planes that, if necessary, can be matched with histologically treated sections. As a result, the morphological information obtained with the scanning electron microscope can be compared in detail with the information on the molecular phenotypes of the subpopulations of cells as deducted from staining patterns of the sections. This method allows combination of the specific advantages of sophisticated histological techniques, such as immunohistochemistry and in situ hybridisation, with those of the scanning electron microscope.

Animals↗

PubMed1996

Evidence for aggregation in oxalate stone formation: atomic force and low voltage scanning electron microscopy.

PURPOSE: The aim of this investigation was to differentiate between aggregation and crystal growth by studying the structure of oxalate stones at high spatial resolution using recently developed microscopy techniques. MATERIALS AND METHODS: Sections from 6 complete human oxalate stones and 4 stone fragments were prepared by ultramicrotomy and examined by both low voltage scanning electron microscopy and atomic force microscopy. RESULTS: The scanning electron microscopy showed lamellar structures up to 10 microns. in size, consistent with previous results, and provided evidence that these structures were composed of smaller particles. The atomic force microscopy clearly showed arrays of the small particles, whose size varied between 500A and 2800A. CONCLUSION: Our images suggest that an ordered aggregation of small crystallites is responsible for oxalate stone formation.

Humans↗

PubMed1979

Scanning electron microscopy of rectal mucosa in Crohn's disease.

Rectal biopsies from healthy control subjects, and from patients with Crohn's disease whose rectal mucosa appeared normal by sigmoidoscopy and light microscopy, were examined by scanning electron microscopy. Appearances within both groups were quite variable, and no clear differences between the groups could be distinguished.

Adolescent↗