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PubMed1992

Correlative transmission electron microscopy and high resolution scanning electron microscopy studies on the fine structural organization of the chicken pituitary gland.

The present study employs transmission (TEM) and high-resolution scanning electron microscopy (HR-SEM) to examine the inter- and intra-cellular organization of the pars distalis of the chicken anterior pituitary gland. The overall view of the cryofractured surface of the par distalis illustrates the arrangement of different pituitary cells and tissues in the follicles. Fine structural examination by HR-SEM shows that the membrane of the mitochondria has a similar configuration to that of the rough endoplasmic reticulum. Granule-like structures, on the surface of the mitochondrial membrane, are similar in size to ribosomes. Standard imaging and three-dimensional imaging demonstrated the formation of developing granules inside the Golgi sacs and the release of mature granules from the end of Golgi stacks. The occurrence of granule-granule connections suggests that granules may be released by exocytosis in groups or individually.

Actin Cytoskeleton↗

PubMed1989

Rapid diagnosis in varicella and herpes zoster: re-evaluation of direct smear (Tzanck test) and electron microscopy including colloidal gold immuno-electron microscopy in comparison with virus isolation.

The Tzanck test and electron microscopy with the technique of colloidal gold labelling in varicella-zoster virus (VZV) infections were compared with virus isolation in 54 patients with clinically suspected varicella or herpes zoster infection. The Tzanck test and direct electron microscopy can determine whether or not an eruption is herpetic but cannot distinguish between herpes simplex virus (HSV) and VZV infection. However, colloidal gold immuno-electron microscopy, using monoclonal antibodies against HSV and anti-VZV IgG, can distinguish between these two herpes viruses. This achieves the same specificity as virus isolation followed by virus neutralization or virus typing using immunofluorescence techniques. The Tzanck test was positive in 91%, virus isolation, under optimal conditions of sampling and transportation, in 80%, direct electron microscopy (negative staining) in 80%, and colloidal gold immuno-electron microscopy after a virus concentration procedure in 95% of the cases. The colloidal gold technique offers a rapid diagnosis in patients with suspected VZV infection.

Adolescent↗

PubMed1989

Dynamics of epidermal growth factor receptor internalization studied by Nanovid light microscopy and electron microscopy in combination with immunogold labeling.

Individual gold particles with a diameter of approximately 10 to 40 nm can be visualized using video-enhanced contrast microscopy (Nanovid) (De Brabander et al., Cell Motil. Cytoskel. 6, 105-113 (1986)). This technique allows a study of the dynamic properties of receptors and ligands in living cells at high resolution. We have studied epidermal growth factor (EGF) receptor internalization in human epidermoid carcinoma A431 cells, using a monoclonal anti-EGF-receptor antibody conjugated to 20-nm gold particles, referred to as 2E9-gold. Exposure of A431 cells to 2E9-gold at 37 degrees C resulted in binding of the complex at the cell surface. Most of the gold particles exhibit a Brownian type of movement, while a minority appeared immobile. Binding of the 2E9-gold complex is followed by internalization, as judged from Nanovid light microscopy studies in combination with electron microscopic observations. The internalized gold particles clearly cluster into large aggregates, most likely multivesicular bodies. Individual gold particles as well as aggregates are characterized by a saltatory movement, by which the gold particles eventually move from the cell periphery towards the cell center. Addition of EGF results in an increased rate of internalization of 2E9-gold, while Na-azide and nocodazole completely immobilize the intracellular gold particles, as has been demonstrated previously for the transferrin receptor.

Adenosine Triphosphate↗

PubMed1980

Light microscopy, scanning electron microscopy, and microprobe analysis of bone response to zinc and nonzinc amalgam implants.

Freshly mixed, unset zinc-free and zinc-containing analgam was implanted in the right tibia of 32 rats. Half of the specimens were examined by the light microscope and the other half by the scanning electron microscope and x-ray microprobe analysis. It was found that amalgam is well tolerated by the rat osseous tissue, and there were no histologic reaction differences between zinc and zinc free amalgam. The surfaces of the implants were covered by an organic film at 3 weeks and with bone at later intervals. Very little corrosion products containing sulfur were observed on the amalgam surface at all intervals. Bone adjacent to the amalgam contained tin and sulfur irrespective of the presence of zinc in the alloy, indicating outward migration of specific components of the alloy.

Animals↗

PubMed1990

Thickness measurements on V79-4 cells: a comparison between laser scanning confocal microscopy and electron microscopy.

A quantitative comparison has been carried out between laser scanning confocal microscopy on living cells and standard electron microscope methods on fixed samples. It was estimated from these measurements that there was about 10-20% reduction in thickness in fixed samples of monolayer V79-4 hamster cells. Precise information on the true thickness of living cells, as irradiated, is required for full interpretation of radiobiological data with poorly penetrating radiations, including ultrasoft X-rays. The confocal microscope allows rapid measurements on unperturbed living samples.

Animals↗

PubMed1985

Identification of a subpopulation of primary granules in human neutrophils based upon maturation and distribution. Study by transmission electron microscopy cytochemistry and high voltage electron microscopy of whole cell preparations.

Two main classes of primary granules have been identified in human neutrophils by peroxidase cytochemistry and electron microscopy, spherical granules and elongated granules, containing crystals with well-defined periodicity. In the present study, we report another subpopulation of primary granules, distinguishable from the other primary granules by their small size, strong peroxidase reactivity under selective incubation conditions with diaminobenzidine, stage of neutrophil maturation at which they appear, and distinctive morphological characteristics. Early promyelocytes, reacted with diaminobenzidine before fixation, demonstrate no reactivity in the large primary granules, but strong peroxidase activity in the endoplasmic reticulum and Golgi apparatus. At the end of the promyelocyte stage of maturation, when the endoplasmic reticulum decreases in peroxidase reactivity, small, round or elongated granules (100 to 200 nm) are observed, reacting strongly for peroxidase. These small granules persist during maturation. The data suggest that these small granules are packaged after the large primary granules and before the secondary granules. All three classes of primary granules exhibit peroxidase activity when fixed prior to incubation in diaminobenzidine at neutral or alkaline pH. Distinctive morphological characteristics of the small primary granules are observed in circulating neutrophils. The small granules are arranged in chains or clusters primarily at the cell margin or uropod in moving cells and are aligned along the axis of cell polarity. This granule association is more evident in adherent neutrophils, particularly after short incubation with phorbol myristate acetate. Chains consisting of as many as 17 small granules are observed. Stereo high voltage electron microscopy of whole-mount preparations of adherent neutrophils reveals chains of small granules apparently interconnected by microtrabeculae. Thus, the small granules observed in thin sections do not represent a transverse section of elongated granules, and the interconnection of granules by microtrabeculae may determine the arrangement of granules. These data support the existence of subpopulations of primary granules which contain distinct forms of myeloperoxidase.

Bone Marrow↗

PubMed1998

Electron microscopy: use of transmission and scanning electron microscopy to study cells in culture.

Standard techniques for electron microscopy were developed for tissues dissected from animals. Optimal methods for electron microscopy of cells in culture are different. This chapter describes methods for processing cells grown on plastic or in suspension. Both transmission and scanning electron microscopy are discussed. The focus is on the procedures for fixation, dehydration, embedding, and staining, which will help the reader to obtain superior electron micrographs of cultured cells.

Animals↗

PubMed1979

Glomerulonephritis induced by high doses of ovalbumin. Studies by electron microscopy, immunofluorescence and immuno-electron microscopy.

Experimental glomerulonephritis was produced in 16 rabbits by intravenous injections of ovalbumin in high doses (0.1 g/day during the first week, 0.2 g x 6/day during the second). The animals were killed on day 14. At that time all animals had 2--4+ proteinuria and a serum C3 level reduced to about 50% of the control level; 11 animals had a significantly raised blood urea level. In all rabbits the antigen had induced severe proliferative glomerulonephritis. Electron microscopy showed that many of the cells accounting for the hypercellularity were monocytes. Surprisingly, electron dense deposits were few and small, mainly on the subendothelial and subepithelial aspects of the glomerular basement membrane. In all the animals ultrastructural immunoperoxidase technique revealed deposits containing ovalbumin, rabbit IgG and C3. With immunofluorescence sparse deposits were occasionally seen. It is concluded that a severe experimental glomerulonephritis can be produced in a state of antigen excess, with the deposition of immune complexes being minimal. Immuno-electron microscopy is essential, however, in detecting even the smallest animals of deposited immune reactants.

Animals↗

PubMed1976

Study on development of Agaricus bisporus by fluorescent microscopy and scanning electron microscopy.

Two strains of Agaricus bisporus have been investigated by fluorescent microscopy and scanning electron microscopy. Somatic nuclei, stained with auramin O and examined by fluorescent microscopy, appear to be randomly distributed, divide asynchronously, and assume a nonclassical or "two-track" configuration during mitotic metaphase. A similar configuration has been observed for nuclei during meiosis, but early meiosis in A. bisporus appears to be classical, usually with nine pairs of chromosomes evident during prophase I. Scanning electron microscopy has been used to document developmental stages in the formation and germination of basidiospores. Two-spored basidia were predominant, but occasionally one- or three-spored forms were observed. Four-spored basidia were absent, and uninucleated basidiospores were exceedingly rare to absent.

Basidiomycota↗

PubMed1983

A method for the detection of amyloid in human tissue embedded in epon using a combination of polarizing light microscopy and electron microscopy.

This paper describes a method for demonstrating amyloid in human tissue embedded in epon using a combination of congo red staining and polarizing microscopy. The method involves the removal of the embedding medium from semi-thin sections prior to staining with congo red and examination in the polarizing microscope. Typical apple green birefringence was detected in areas of amyloid deposition; these areas were mapped for selective trimming and ultra-thin sections taken serially were examined in the electron microscope. The method was found to be reliable, easy to use and particularly of value as a sampling procedure prior to investigation in the electron microscope.

Amyloid↗

PubMed1985

[The neurocytes of the caudal part of the tuberomamillary nucleus in Ovis aries L. (light microscopy and electron microscopy studies)].

The neurons of the pars caudalis nuclei tuberomammillaris (pc-NTM) were studed light-microscopically and electron-microscopically in sheep and rams of Merino breed. In our study we observed: In the regarded neural nucleus, there is the majority of the great neurons (up to 60 microns in diameter) rich in the NISSL's bodies. When stained with the cresyl violet, the NISSL's substance is apparently stored mainly in peripheral area of the cell body and in the distant parts of numerous protoplasmic processes, what evokes an impression of the "jagged" surface of these cells. After staining with paraldehyde fuchsin, we found purple coloured lumps of irregular shape stored outside the cell bodies, in the neuropil. The less extended cells, usually with lower content of NISSL bodies, are in pc-NTM less frequent. In the electron-microscopic study we identified 3 types of neurons: Cells rich in rough endoplasmic reticulum; "light" cells, "dark" cells. The cells of the 1st type were the most frequent ones. Cisterns of rough endoplasmic reticulum in the 1st type of cells are often dilated. The protoplasmic processes of these cells are frequently stepped over by flat tubuli of endoplasmic reticulum. The 2nd type of cells is characterized by the light cytoplasmic matrix, low quantity of endoplasmic reticulum and frequent occurrence of lipofuscin bodies. The 3rd type of cells are characterized by the high density of cytoplasmic matrix, well developed GOLGI complex, and very broad cisterns of endoplasmic reticulum, forming a labyrinth, and it is bound to a broad perinuclear space.

Animals↗

PubMed1991

High voltage electron microscopy and low voltage scanning electron microscopy of human neoplastic cell culture.

Improved procedures were developed to correlate cell culture data with the images provided by advanced ultrastructural technologies. These procedures were compatible with the two main types of cellular behavior: adherent, spreading (melanomas, rhabdomyosarcomas) and non-adherent in suspension (leukemias). The ultrastructure and function of spreading neoplastic cells primarily depend on surface properties of the attaching substrates. Therefore, the films used for cultured cell whole-mount ultrastructural analysis must have adherence features identical to those of standard cell culture vessels. Improved procedures were developed to produce the polystyrene films of required qualities. These films allowed processing of cells for electron microscopy including chemical fixation, cryo-immobilization, and immunolabelling. Furthermore, these polystyrene films permitted observations of the same cell in the high voltage electron microscope to reveal the internal organization and in the low voltage scanning electron microscope to reveal the surface topography. Neoplastic cells in suspension may dramatically change their ultrastructure as a result of interactions with substrates or other cells. Therefore, immobilization of cellular processes must occur rapidly while cells remain in suspension. These processes were cryo-immobilized by high pressure freezing through the use of the newly designed specimen carrier. Procedures allowing high yield attachment of cryo-fixed neoplastic cells to amino-propyl-derived glass carriers enabled observations of cell surface topography. Furthermore, freeze-substitution and drying of freeze-fractured cells revealed their three-dimensional internal organization in the low voltage scanning electron microscope.

Cryopreservation↗

PubMed1969

Spatial patterns of threadlike elements in the axoplasm of the giant nerve fiber of the squid (Loligo pealii L.) as disclosed by differential interference microscopy and by electron microscopy.

The giant nerve fiber of the squid (Loligo pealii L.) has been investigated in situ, and in fresh and fixed preparations, by differential interference microscopy and electron microscopy. A continuous, three-dimensional network, composed of threadlike elements, was disclosed in the axoplasm. The threadlike elements in the axoplasm are twisted as a whole into a steep, right-handed helix. In a peripheral ectoplasmic region, the elements are more parallel to one another and more densely packed than in a central endoplasmic core. The threadlike elements can be resolved into a hierarchy of decreasing order of size. Successive levels of the hierarchy are formed by the association of smaller elements into larger ones. The following levels in the hierarchy of network elements have been distinguished: 1-3-micro-wide threads, 0.1-0.35-micro-wide strands, and 70-250-A-wide unit-filament strands. The differential interference microscope selects, from the network, threads oriented at a specific angle to the long axis of the axon. The specific angle depends upon the orientation of the long axis of the axon relative to the direction of shear. It is postulated that the network configuration is expressed in the solid-state properties of the axoplasm essential for the normal functioning of the nerve fiber.

Animals↗

PubMed1977

[Examination of gallstones on their surface and in fractured cross sections by incident light microscopy and scanning electron microscopy (author's transl)].

Operatively removed gallstones were examined on their surfaces and in fractured cross sections by incident light microscopy and scanning electron microscopy. In addition, micro-bore samples and X-ray crystallography were done. Five gallstone types consisting of three basic structural layers are differentiable by incident light microscopy. The three layers consist of a central nucleus which is always present, a radially structured middle layer, and a fine crystalline outer shell, the presence or absence of the latter two layers differentiating the stone types. Two crystal structures could be differentiated by electron microscopy; a flat and a globular type. The nucleus is always of the globular crystalline type, while the outer layers are flat crystalline. From this we were lead to believe that the conditions in vivo, under which the different layers of a gallstone are built, change. The micro-bore samples lead us to believe that calcium is only secondarily layed down in the gallstone framework. White crystalline deposits, which were formed several seconds after fracture, were discovered on the fractured gallstone cross sections.

Cholelithiasis↗

PubMed1975

Transmission electron microscopy of tissue prepared for scanning electron microscopy by ethanol-cryofracturing.

Tissue processed for scanning electron microscopy by ethanol-cryofracturing combined with critical point drying was embedded and sectioned for transmission electron microscopy. Study of specimens cut in a plane passing through the fracture edge indicated that preservation of cellular fine structure of fractured cells was excellent. Even at the most peripheral edge of the fracture there was no evidence that movement of cytoplasmic components occurred to distort the original structural organization of fractured cells. Lack of cytoplasmic detail in ethanol-cryofractographs has been due more to the nature of the fracturing of the tissue and to the obscuring effects of the metal coating than to structural deformation at the fracture edge or to limitations in resolving power of the scanning electron microscope used.

Animals↗

PubMed1986

The Kupffer cell in experimental extrahepatic cholestasis in the rat--a light microscopy, immunohistochemical and electron microscopy study.

Kupffer cell phagocytic function is reduced in the presence of obstructive jaundice. To investigate possible mechanisms we report a study of the rat liver in extrahepatic cholestasis, using light microscopy, immunohistochemistry and electron microscopy, Immunohistochemistry was performed with monoclonal antibodies specific for rat Kupffer cells ED 1, ED 2 and ED 3 and monoclonal antibodies directed against class II antigens of the rat major histocompatibility complex Ox 3 and Ox 6. Extrahepatic cholestasis was produced by bile duct ligation. In bile duct ligated animals light microscopy showed proliferation of bile ductules and an increase in sinusoidal cells. Immunohistochemistry with ED 1, ED 2 and ED 3 demonstrated a marked increase in the number of positive cells, but few of these cells were positive with Ox 3 and Ox 6, whereas the proliferating bile ductules were strongly positive. Electron microscopy revealed two homogeneous granular substances within the sinusoidal lumen and loss of the space of Disse. Despite a reduction in Kupffer cell phagocytic function in obstructive jaundice there is an increase in Kupffer cells, but these cells appear to be in an inactivated state as few express class II antigens on their surface. Furthermore the granular substance within the space of Disse may interfere with function.

Animals↗

PubMed2002

[Morphogenesis of media calcinosis in Mönckeberg disease. Light microscopy, scanning electron microscopy and roentgen microanalysis findings].

OBJECTIVE: In contrast to granular mediacalcinosis of the aorta, Mönckeberg's disease is characterized by the occurrence of sheet-like calcification. It is usually said that the pathogenesis of this calcification is unknown. MATERIAL AND METHODS: To obtain some insight into the mechanism leading to this calcification, we performed light microscopic, scanning electron microscopic and X-ray microanalysis investigations on femoral arteries from autopsies. RESULTS: By light microscopy preferentially sheet-like calcifications of different size appeared. In the alizarin red S stain in the neighborhood of these compact structures calcified globules were observed. By SEM in the neighborhood of the compact areas calcified granules were found; the compact structures themselves consisted of granules sticking one onto the other. X-ray microanalysis exhibited high contents of calcium and phosphorus in the compact calcifications; they also showed a minor content of magnesium. Isolated granules inside the compact calcifications showed a nearly identical composition, while granules outside in the surrounding media consisted preferentially from calcium and phosphorus, but they exhibited a slight higher magnesium content. CONCLUSIONS: It is concluded that Mönckeberg's media calcification is due to dystrophic calcification. Calcified matrix vesicles from necrotic cells, as it is assumed for the pathogenesis of the calcification of arteriosclerotic plaques (31), are interpreted as precursors of the solid calcifications which may develop by confluence and sticking one onto the other of calcified globules.

Aged↗

PubMed1997

Long-term evaluation of bone-titanium interface in rat tibiae using light microscopy, transmission electron microscopy, and image processing.

We conducted a 2-year histologic and histometric evaluation of the tibial bone-titanium (Ti) implant interface in male rats. Thirty male 6-week-old rats were used in this study. They were divided into two groups: 15 for day 28 and 15 for day 730. Microscopic observation at day 28 revealed that the newly formed bone around the implant almost surrounded the implant, but fibroblastlike cells were interposed in some histologic sections. At day 730, in contrast, such cells were rarely seen, and the bone around the implant presented a lamellar structure. Transmission electron microscopic observation at day 28 disclosed mature or poorly mineralized bone near the implant; however, an electron-dense amorphous zone about 50 nm in thickness was interposed between the bone and Ti. In places slender cells were interposed between the bone and Ti. The amorphous zone was also observed at the cell-Ti interface. At day 730, a poorly mineralized layer remained in some areas between the mature bone and the titanium, and the interposed amorphous zone was still observed. Occasionally, a 200-nm-thick layer, thought to be cell remnant, was seen. As calculated in an image-processing, system analysis, the percent bone contact and the thickness and area of the surrounding bone for the Ti implant at day 28 were 43.6%, 30.4 microns, and 0.10 mm2, respectively, and those at day 730 were 89.9%, 53.5 microns, and 0.19 mm2, respectively. In summary, although the passage of time may affect bone maturity, interfacial cells remain at the bone-Ti interface as a uniform layer together with unmineralized bone.

Animals↗