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At least 37 records · Page 2Linked to original sources
PubMed1979

Morphological studies on the periostracum of the fresh-water mussel Amblema (Uniondae): light microscopy, transmission electron microscopy, and scanning electron microscopy.

The structure of the periostracum in the fresh-water mussel Amblema has been described using light microscopy, transmission elec;ron microscopy, and scanning electron microscopy. The structure and evolutive course of the periostracum was studied along its entire length, from the periostracal groove until it forms the tough outer covering of the shell. At least five structurally and functionally distinct regions were identified. In addition, the periostracum itself was seen to be a multilayered structure consisting of three major layers which are themselves subdivided into minor layers. From these morphological observations, a regulatory role for the various periostracal layers in mineral trapping, nucleation, and the subsequent formation of the prismatic and nacreous layers of the shell can be postulated.

Animals↗
PubMed1987

Pitfalls of immunogold labeling: analysis by light microscopy, transmission electron microscopy, and photoelectron microscopy.

The immunogold method is widely used to localize, identify, and distinguish cellular antigens. There are, however, some pitfalls that can lead to nonspecific binding, particularly in cytoskeletal studies with gold probes prepared from small gold particles. We present a list of suggestions for minimizing nonspecific binding, with particular attention to two problems identified in this study. First, we find that the method used to prepare the colloidal gold particles affects the degree of nonspecific binding. Second, the standard BSA-stabilized small gold probes evidently possess exposed regions that bind to the proteins of cytoskeletal preparations. This was investigated in whole-mount cytoskeletal preparations of cultured cells by use of light microscopy, transmission electron microscopy, and photoelectron microscopy of silver-enhanced specimens. Gold probes were made from approximately 5-nm particles generated by reduction of HAuCl4 with three different reducing agents: white phosphorus, sodium borohydride, and citrate-tannic acid. All three preparations stabilized in the conventional way showed significant levels of nonspecific binding, which was highest with citrate-tannic acid. This problem was largely solved with all three types of probes by including fish gelatin in the probe buffer, by substituting fish gelatin for the BSA stabilizer used to prepare the probes, or by pre-adsorption methods. Application of these techniques resulted in clear immunogold labeling patterns with minimal nonspecific background.

Actins↗
PubMedDate not supplied

Scanning electron microscopy in the study of lung cancer. New technique of comparative studies on the same lung cancer cells by light microscopy and scanning electron microscopy.

A new technique for observing the same lung cancer cells by light microscope and SEM was developed. By this technique it was clarified that the surface ultrastructures of epidermoid carcinoma, adenocarcinoma and oat-cell carcinoma cells are different from each other. Those of adenocarcinoma and mesothelial cells were quite different. This technique might be of use, adding new information into the ordinary cytologic diagnosis of cancer cells.

Adenocarcinoma↗
PubMed1990

Correlative light microscopy, scanning electron microscopy, and transmission electron microscopy of osmium-macerated biological tissues.

A method facilitating correlation of light microscopic (LM), scanning electron microscopic (SEM) and transmission electron microscopic (TEM) images was developed. Rat kidney and heart were initially subjected to the osmium maceration procedure and then embedded in acrylic resin. Semithin sections of the tissue blocks were first provided for LM and then examined by SEM after resin removal. Furthermore, the ultrathin sections adjacent to the semithin sections were observed by TEM. The three-dimensional images of intracellular organelles provided an informative adjunct to LM and TEM.

Animals↗
PubMed1998

[Significance of histopathologic analysis of skin lesions in scleromyxedema. Light microscopy, electron microscopy, immunohistochemistry and immunofluorescence microscopy].

Scleromyxedema (SM) may be considered as a possible disease entity in the differential diagnosis of scleroderma. Clinical data and the results of light, immunohistochemical, immunofluorescence and electron microscopic study of skin biopsies taken from a 53-year old patient with SM are reported. In the patient with SM in which abnormal serum paraprotein was not identified, the skin biopsy showed mucinous material in the dermis and proliferation of fibroblasts accompanied by mild dermal sclerosis. Immunofluorescence showed scanty granular IgG along the epidermal basement membrane and IgG and C1q focally along the connective tissue fibres in the dermis of clinically involved skin. In addition to clinical findings, detailed skin biopsy studies including contemporary techniques can contribute to the diagnosis of the disease.

Biopsy↗
PubMed1983

[Muscular changes caused by suction drainage. Scanning electron microscopy, transmission electron microscopy, light microscopy and morphometric studies of dorsal muscles of the rat (Rattus rattus) using drainage].

Changes in the dorsal muscles of 22 rats (Wistar), resulting from surgical drain, have been studied under different morphological aspects. The lumen of drains were obstructed after a short time. In the drains without using low pressure, erythrocytes and fibrin network were seen by scanning microscopical investigation. Patent muscle fibres could be analyzed in the lumen of drain using negative pressure. They prevent the functional drain system. By the effect of surgical drains the fibres of dorsal muscles had become swollen. This fact could be analyzed by morphometrical technique. Some changes in fibres have been demonstrated by histological methods.

Animals↗
PubMed1985

Immunophotoelectron microscopy: the electron optical analog of immunofluorescence microscopy.

The electron optical analog of immunofluorescence microscopy combines three developments: (i) photo-electron microscopy to produce a high-resolution image of exposed components of the cell, (ii) site-specific antibodies, and (iii) photoemissive markers coupled to the antibodies to make the distribution of sites visible. This approach, in theory, provides a way to extend the useful immunofluorescence microscopy technique to problems requiring much higher resolution. The resolution limit of fluorescence microscopy is limited to about 200 nm by the wavelength of the light used to form the image, whereas in photoelectron microscopy the image is formed by electrons (current resolution: 10-20 nm; theoretical limit: 5 nm or better depending on the electron optics). As a test system, cytoskeletons of CV-1 epithelial cells were prepared under conditions that preserve microtubules, and the microtubule networks were visualized by both indirect immunofluorescence and immunophotoelectron microscopy using colloidal gold coated with antibodies. Colloidal gold serves as a label for immunophotoelectron microscopy, providing enhanced photoemission from labeled cellular components so that they stand out against the darker background of the remaining unlabeled structures. In samples prepared for both immunofluorescence and immunophotoelectron microscopy, individual microtubules in the same cells were visualized by both techniques. The photoemission of the colloidal gold markers is sufficiently high that the microtubules are easily recognized without reference to the immunofluorescence micrographs, indicating that this approach can be used, in combination with antibodies, to correlate structure and function in cell biological studies.

Animals↗
PubMed2006

Reflection contrast microscopy: The bridge between light and electron microscopy.

Reflection contrast microscopy (RCM) is a light microscopic method to image cells at high definition and enhanced sensitivity compared to conventional bright-field microscopy. RCM images have very high contrast, which makes them easily applicable for digital image analysis. Because ultrathin sections are mostly used in this method, RCM also functions by bridging light with electron microscopy: the combination of ultrastructural with histochemical studies. RCM can also replace electron microscopy for rapid and simple screening of large quantities of samples for immunocytochemical staining. Special attention is paid to small biological objects, which have to be processed for RCM. If you encounter the limits of brightfield microscopy, in resolution, sensitivity or handling of the specimen, RCM will be a feasible option. Reflection contrast microscopy methods use only slightly adjusted electron microscopy methods for specimen preparation. Therefore, many familiar techniques for ultrathin specimen preparation can be applied. It is essential that only refractive index differences exist in those areas that are of interest and that the further specimen is as optically homogenic as possible, with a refractive index as close to that of glass as possible. Therefore, plastic embedding is recommended.

Animals↗
PubMed2005

Atomic force microscopy and confocal laser scanning microscopy on the cytoskeleton of permeabilised and embedded cells.

We describe a technical method of cell permeabilisation and embedding to study the organisation and distribution of intracellular proteins with aid of atomic force microscopy and confocal laser scanning microscopy in identical areas. While confocal laser scanning microscopy is useful for the identification of certain proteins subsequent labelling with markers or antibodies, atomic force microscopy allows the observation of macromolecular structures in fixed and living cells. To demonstrate the field of application of this preparatory technique, cells were permeabilised, fixed, and the actin cytoskeleton was stained with phalloidin-rhodamine. Confocal laser scanning microscopy was used to show the organisation of these microfilaments, e.g. geodesic dome structures. Thereafter, cells were embedded in Durcupan water-soluble resin, followed by UV-polymerisation of resin at 4 degrees C. This procedure allowed intracellular visualisation of the cell nucleus or cytoskeletal elements by atomic force microscopy, for instance to analyse the globular organisation of actin filaments. Therefore, this method offers a great potential to combine both microscopy techniques in order to understand and interpret intracellular protein relations, for example, the biochemical and morphological interaction of the cytoskeleton.

Actins↗
PubMed1983

Ultrastructural pathology of Crohn's disease: correlated transmission electron microscopy, scanning electron microscopy, and freeze fracture studies.

The mucosa of the ileum or colon from 16 patients with active Crohn's disease was studied using transmission electron microscopy of thin sections, scanning electron microscopy, and freeze fracture electron microscopy. Electron micrographs of diseased tissue, as well as of grossly normal resection margins, were studied. Correlations of mucosal disease, as seen with the various ultrastructural techniques, were made and compared to controls. Alterations of epithelial cell tight junctions in freeze fracture replicas correlated with a decrease in the number of pinpoint contacts between adjacent cells in transmission electron microscopy preparations. Gap junctions in Crohn's disease did not vary with respect to structure or number, when compared to controls. Mucosal microulcerations, affecting 1 to 6 cells, were observed in transmission and scanning electron microscopy preparations. Possible freeze fracture electron microscopy correlates of microulcers consisted of replicas of cells completely devoid of tight junctional structures. "Aphthoid" type ulcers were studied with the various ultrastructural tools and were remarkable for several abnormalities of villi bordering the aphthoid ulcers, as well as surrounding villi. Transmission, scanning, and freeze fracture electron microscopy each provide unique and confirming data that may be used to construct a model for the pathophysiology of Crohn's disease.

Colitis↗
PubMed1997

A comparison of conventional microscopy, immunofluorescence microscopy and flow cytometry in the detection of Giardia lamblia cysts in beaver fecal samples.

A variety of domestic and wild animals are considered to be potential sources of giardiasis in humans. As a result, numerous studies have been reported on the prevalence of Giardia lamblia infection in animals. The majority of these surveys have involved various floatation techniques followed by conventional microscopy in order to detect cysts in fecal samples. Immunofluorescence microscopy has become popular in recent years for the detection of G. lamblia cysts in both clinical and environmental samples. This technique can be automated by combining it with flow cytometry. The present study represents a direct comparison of conventional microscopy, immunofluorescence microscopy, and flow cytometry in terms of their relative efficiency in the detection of G. lamblia cysts in beaver fecal samples. As a result of viewer fatigue, or low cyst concentrations, false negatives were common with conventional microscopy, leading to low prevalence estimates. By specifically targeting the cysts, immunofluorescence microscopy provided more reliable results in a shorter time than conventional methods. When flow cytometry was used in combination with immunofluorescence, a larger number of samples could be examined in a relatively short period of time. The results obtained indicated that this technique allowed for more consistent recognition than either conventional or immunofluorescence microscopy of positive samples containing smaller numbers of cysts.

Animals↗
PubMed1978

Cytoplasmic microtubular images in glutaraldehyde-fixed tissue culture cells by electron microscopy and by immunofluorescence microscopy.

Electron microscopy and indirect immunofluorescence microscopy using monospecific tubulin antibodies were performed in parallel on glutaraldehyde-fixed tissue culture cells without osmium fixation. In order to reduce the excess aldehyde groups of the strongly crosslinked cellular matrix, which normally interfere with subsequent immunofluorescence microscopy, a mild NaBH(4) treatment was introduced during or after the dehydration steps. Cells processed through the NaBH(4) step show, in transmission electron microscopy, normal cytoplasmic microtubules approximately 250 A in diameter. When such cells are subjected to indirect immunofluorescence microscopy using monospecific tubulin antibody they reveal a complex system of unbroken, fine, fluorescent fibers traversing the cytoplasm between the perinuclear space and the plasma membrane. Thin sections of cells processed through the indirect immunofluorescence procedure show antibody-decorated microtubules with a diameter of approximately 600 A. This decoration is not obtained when non-immune IgGs are used instead of monospecific antitubulin IgGs. Thus, a direct comparison of cytoplasmic microtubules in glutaraldehyde-fixed cells by both electron microscopy and immunofluorescence microscopy can be obtained.

Cells, Cultured↗
PubMed1984

Esophageal dysplasia. Assessment by light microscopy and scanning electron microscopy.

This study was performed to determine the characteristics of esophageal dysplasia by scanning electron microscopy. A total of 82 esophageal biopsy specimens were taken from 30 patients who were divided into three groups. Group 1 patients had no known esophageal disease. Group 2 patients had squamous cell cancer. Group 3 patients had esophagitis. Mucosal biopsy specimens that had been diagnosed by light microscopy as normal, esophagitis, or dysplastic mucosa were examined by scanning electron microscopy. A characteristic appearance for each type of mucosa was recognized by scanning electron microscopy. A quantitative analysis of the scanning electron microscopy feature of microridge density showed a statistically significant difference not only between normal and dysplastic mucosa, but also between esophagitis and dysplastic mucosa. The addition of scanning electron microscopy to light microscopy may prove helpful in the diagnosis of dysplasia as well as in the understanding of the biologic behavior of dysplastic cells and possibly their relationship to esophageal carcinoma.

Adult↗