SEARCH · PubMed Health

Results for “Microscopy”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources

PubMed1988

Innervation of the C cells of chicken ultimobranchial glands studied by immunohistochemistry, fluorescence microscopy, and electron microscopy.

Innervation of the ultimobranchial glands in the chicken was investigated by immunohistochemistry, fluorescence microscopy and electron microscopy. The nerve fibers distributed in ultimobranchial glands were clearly visualized by immunoperoxidase staining with antiserum to neurofilament triplet proteins (200K-, 150K- and 68K-dalton) extracted from chicken peripheral nerves. The ultimobranchial glands received numerous nerve fibers originating from both the recurrent laryngeal nerves and direct vagal branches. The left and right sides of the ultimobranchial region were asymmetrical. The left ultimobranchial gland had intimate contact with the vagus nerve trunk, especially with the distal vagal ganglion, but was somewhat separated from the recurrent nerve. The right gland touched the recurrent nerve, the medial edge being frequently penetrated by the nerve, but the gland was separated from the vagal trunk. The left gland was innervated mainly by the branches from the distal vagal ganglion, whereas the right gland received mostly the branches from the recurrent nerve. The carotid body was located cranially near to the ultimobranchial gland. Large nerve bundles in the ultimobranchial gland ran toward and entered into the carotid body. By fluorescence microscopy, nerve fibers in ultimobranchial glands were observed associated with blood vessels. Only a few fluorescent nerve fibers were present in close proximity to C cell groups; the C cells of ultimobranchial glands may receive very few adrenergic sympathetic fibers. By electron microscopy, numerous axons ensheathed with Schwann cell cytoplasm were in close contact with the surfaces of C cells. In addition, naked axons regarded as axon terminals or "en passant" synapses came into direct contact with C cells. The morphology of these axon terminals and synaptic endings suggest that ultimobranchial C cells of chickens are supplied mainly with cholinergic efferent type fibers. In the region where large nerve bundles and complex ramifications of nerve fibers were present, Schwann cell perikarya investing the axons were closely juxtaposed with C cells; long cytoplasmic processes of Schwann cells encompassed large portions of the cell surface. All of these features suggest that C-cell activity, i.e., secretion of hormones and catecholamines, may be regulated by nerve stimuli.

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↗

PubMed1985

Structural organization of an active, chromosomal nucleolar organizer region (NOR) identified by light microscopy, and subsequent TEM and STEM electron microscopy.

The three-dimensional arrangement of the chromatin components within the nucleolar organizer regions (NORs) from living oocyte nuclei was investigated. As a suitable cell system we chose vitellogenic oocytes of the orthopteran insect Acheta. This cell type is particularly attractive for analysis of nucleolar chromatin, since structural and functional aspects of NORs during early oogenic stages (including the association of NORs with amplified rDNA copies) are particularly well known (Lima-de-Faria 1974). In the course of the present study we first identified putative chromosomal NORs in isolated nuclei of mid-diplotene oocytes according to morphological characteristics using differential interference contrast (DIC) or phase contrast light microscopy. The presence of actively transcribing chromosomal NORs during this late stage of Acheta oogenesis obviously had been overlooked by previous investigators, probably due to difficulties of chromosome visualization. For a more detailed ultrastructural analysis, NORs were gently sedimented from opened nuclei and processed for sectioning using a modified "end-embedding" procedure (Mott and Callan 1975; Spring and Franke 1981). A small number of thick and thin sections could be made from individual NORs. Sections were analyzed by light microscopy, conventional transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). Whereas the structural connection of NORs to the chromosome axis and also the general arrangement of active nucleolar genes within the NOR complex could be seen with TEM, the visualization of individual nucleolar genes and the organization of transcription complexes was only possible using bright field STEM of thick sections at low temperature.

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↗

PubMed1983

Light microscopy, electron microscopy, and X-ray diffraction analysis of glycerinated collagen fibers.

Light microscopy, transmission electron microscopy (freeze-fracture replicas and thin sections), and X-ray diffraction techniques were used to investigate the structure of rat tail tendon collagen fibers subjected to one of the following treatments: water, phosphate buffer, glutaraldehyde, glutaraldehyde followed by glycerol, glycerol, and glycerol followed by phosphate buffer. As seen by light microscopy, only treatment with glycerol induces a remarkable swelling of the native (untreated) collagen specimens. Replicas and thin sections show that this swelling is due to an expansion of the interfibrillar space, and to a dissociation of the collagen fibrils into microfibrils. X-Ray diffraction analysis reveals great disorder in the glycerol-swollen collagen fibers. However, this does not appreciably involve the microfibrillar and molecular structure. Light and electron microscopy as well as X-ray diffraction techniques show that the collagen fiber swelling induced by glycerol is an almost completely reversible process.

Animals↗

PubMed1989

Temporal artery biopsies. Correlation of light microscopy and immunofluorescence microscopy.

Immunopathologic studies are done routinely on biopsy specimens from tissues affected by many autoimmune diseases. To evaluate the role of direct immunofluorescence microscopy (DIFM) in identifying temporal arteritis, the authors reviewed all temporal artery biopsies done over a 30-month period (100 consecutive biopsies). The DIFM, using antibodies to IgG, IgM, IgA, complement, and fibrinogen, had a diagnostic sensitivity rate of 93% and a specificity rate of 87% compared with light microscopy. In biopsy specimens showing arteritis by light microscopy, IgG was demonstrated by DIFM in 85% of cases, IgM in 69%, and IgA in 15%. In one patient, a DIFM staining pattern highly suspicious of temporal arteritis identified a patient with features of clinical temporal arteritis despite negative findings by light microscopy. The demonstration of immunoglobulin by DIFM supports the possible role of humoral immunity in the pathogenesis of temporal arteritis.

Aged↗

PubMed1983

Photoelectron microscopy and immunofluorescence microscopy of cytoskeletal elements in the same cells.

Pt K2 rat kangaroo epithelial cells and Rat-1 fibroblasts were grown on conductive glass discs, fixed, and permeabilized, and the cytoskeletal elements actin, keratin, and vimentin were visualized by indirect immunofluorescence. After the fluorescence microscopy, the cells were postfixed and dehydrated for photoelectron microscopy. The contrast in these photoelectron micrographs is primarily topographical in origin, and the presence of fluorescent dyes at low density does not contribute significantly to the material contrast. By comparison with fluorescence micrographs obtained on the same individual cells, actin-containing stress fibers, keratin filaments, and vimentin filaments were identified in the photoelectron micrographs. The apparent volume occupied by the cytoskeletal network in the cells as judged from the photoelectron micrographs is much less than it appears to be from the fluorescence micrographs because the higher resolution of photoelectron microscopy shows the fibers closer to their true dimensions. Photoelectron microscopy is a surface technique, and the images highlight the exposed cytoskeletal structures and suppress those extending along the substrate below the nuclei. The results reported here show marked improvement in image quality of photoelectron micrographs and that this technique has the potential of contributing to higher resolution studies of cytoskeletal structures.

Actins↗

PubMed1979

Morphological studies of the spleen in idiopathic portal hypertension (so-called Banti's syndrome without liver cirrhosis) using light microscopy, scanning electron microscopy and histometry.

Morphological changes in the spleens of patients with idiopathic portal hypertension (IPH) were studied and compared with the normal spleen. The study used (1) light microscopy with histometry, (2) scanning electron microscopy (SEM) of the splenic tissue with histometry and (3) SEM of the spleen vascular replica. Histometrical studies by light microscopy showed that the volume of red pulp of IPH was increased in a unit area and to a total of 12 times the normal in the whole spleen. The white pulp was scanty of lymphocytes and decreased in a unit area but it was increased in the whole spleen. SEM of the white pulp of IPH demonstrated many channels formed by reticulum cells and running parallel with each other along the central artery. This finding presumably corresponds to periarterial fibrosis in light microscopy. SEM histometry demonstrated that the venous sinuses of IPH were small but increased in number and occupied the same percentage area in a unit red pulp area as in the normal spleen. The Billroth cord of IPH was narrowed and occupied by thickened reticulum cells, which may cause increased pooling and destruction of blood cells in the enlarged spleen (hypersplenism). SEM of the tissue and vascular replica demonstrated open arterial termination in the Billroth cord in the spleen of IPH as well as in the normal spleen. Venous sinuses in the replica of IPH ran parallel with each other forming bundles with fewer intercommunications than normal.

Adult↗

PubMed2003

Rapid detection of biofilms and adherent pathogens using scanning confocal laser microscopy and episcopic differential interference contrast microscopy.

Knowledge of biofilm structure and function has changed significantly in the last few years due to advances in light microscopy. One pertinent example is the use of scanning confocal laser microscopy (SCLM) to visualise corrosion pits caused by the biofilm mosaic footprint on corroding metal surfaces. Nevertheless, SCLM has some limitations as to its widespread use, including cost, inability to observe motile bacteria and eukaryotic grazers within biofilms, and difficulty to scan a curved surface. By contrast, episcopic differential interference contrast (EDIC) microscopy has provided a rapid, real time analysis of biofilms on opaque, curved, natural or man-made surfaces without the need for cover slips and oil. EDIC, coupled with epi-fluorescence (EDIC/EF), microscopy has been used successfully to visualise the 3-D biofilm structure, physiological niches, protozoal grazing and iron biomineralization, and the location of specific pathogens such as Legionella pneumophila, Campylobacter jejuni and Cryptosporidium parvum. These species were identified using gold nanoparticles or fluorophores coupled to monoclonal antibodies or 16S rRNA probes, respectively. Among its many potential uses, the EDIC technique will provide a rapid procedure to facilitate the calibration of the modern generation of biofilm-sensing electrodes.

Animals↗

PubMed1985

Identification of feline monocytes and neutrophils as effector cells in antibody-dependent cellular cytotoxicity: sequential analysis, using light microscopy, histochemistry, and scanning electron microscopy.

Feline monocytes and neutrophils functioned as effector cells in antibody-dependent cellular cytotoxicity (ADCC) against antibody-coated chicken erythrocytes. Using light microscopy, effector cell populations were identified in effector-target cell interactions, with further characterization of these identical individual effector cells by histochemical evaluations and scanning electron microscopy. Monocytes and neutrophils, but not lymphocytes, were observed attacking target cells. Carbonyl iron depletion of monocytes and neutrophils from peripheral blood leukocytes caused a marked reduction from a mean of 62% to 3.6% lysis in ADCC as measured by a 4-hour 51Cr release assay. Effector cells functioning in the ADCC reaction were visualized, using sequential analysis and light microscopy, histochemistry, and scanning electron microscopy.

Animals↗

PubMed1993

Scanning and transmission electron microscopy and high resolution intravital video-microscopy of capillaries in the mouse exocrine pancreas, with special emphasis on endothelial cells.

Capillaries in the mouse exocrine pancreas were studied by scanning electron microscopy of microvascular corrosion casts, transmission electron microscopy of tissue sections, and high resolution intravital video-microscopy. Two types of capillaries were discerned by corrosion casting. The first type was rather straight, had a constant diameter of 5-6 microns, and its surface showed multiple circumferential furrows. The frequency of such constrictions was less in the second type, which was more undulated and had a diameter of 7-9 microns. In the second type, these constrictions defined bulged areas of the capillary cast. Corresponding tissue sections also showed two types of capillaries, fenestrated and non-fenestrated capillaries. Microtubules were abundant in all capillary endothelial cells, whereas bundles of microfilaments were scarce. Microtubules were arranged along the long axis of endothelial cells as well as parallel to endothelial cell border regions. Endothelial cells were joined by intermediate junctions along cell borders running both circumferentially and longitudinally. Flow reversal in capillaries and spontaneous endothelial contractions were documented in vivo. Endothelial cells bulged into the lumen, either at their nuclear region or distant from it. Spontaneous contraction of pericytes was not observed. These results suggest that contraction of capillaries is carried out by endothelial cells, representing an autonomous flow regulatory device. Capillary contraction in exocrine pancreas may be influenced by blood-borne agents, probably by those released in Langerhans islets.

Animals↗

PubMed2003

Atomic force microscopy and scanning near-field optical microscopy studies on the characterization of human metaphase chromosomes.

A better knowledge of biochemical and structural properties of human chromosomes is important for cytogenetic investigations and diagnostics. Fluorescence in situ hybridization (FISH) is a commonly used technique for the visualization of chromosomal details. Localizing specific gene probes by FISH combined with conventional fluorescence microscopy has reached its limit. Also, microdissecting DNA from G-banded human metaphase chromosomes by either a glass tip or by laser capture needs further improvement. By both atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM), local information from G-bands and chromosomal probes can be obtained. The final resolution allows a more precise localization compared to standard techniques, and the extraction of very small amounts of chromosomal DNA by the scanning probe is possible. Besides new strategies towards a better G-band and fluorescent probe detection, this study is focused on the combination of biochemical and nanomanipulation techniques which enable both nanodissection and nanoextraction of chromosomal DNA.

Cell Separation↗

PubMed2003

Combined use of confocal laser scanning microscopy and transmission electron microscopy for visualisation of identical cells processed by cryotechniques.

Successive visualisation of identical plant cells by light and electron microscopy is reported. For this purpose segments of pea and barley leaves were prepared by high-pressure freezing, freeze-substitution, and low-temperature embedding. The use of Safranin O during low-temperature dehydration allowed, on one hand, staining of all cellular components as investigated by confocal laser scanning microscopy and, on the other hand, excellent ultrastructural and antigenic preservation. A newly constructed specimen holder enabled precise relocation of the target cells for electron microscopic investigations. Transmission electron microscopy and immunohistochemistry revealed that during the whole procedure the ultrastructure of the cells as well as the antigenicity of cell constituents were preserved.

Cryoelectron Microscopy↗

PubMed2001

Effects of acetone, methanol, or paraformaldehyde on cellular structure, visualized by reflection contrast microscopy and transmission and scanning electron microscopy.

The authors recently showed variable subcellular immunoreactivity of the Bcl-2 and Bax proteins after fixation of cell monolayers with acetone, methanol, or paraformaldehyde (PF) followed by methanol (PF/methanol). Here, the authors demonstrate by reflection contrast microscopy and transmission electron microscopy that acetone or methanol fixation result in complete loss of integrity of intracellular structures in contrast with PF or glutaraldehyde fixation. Scanning electron microscopy revealed poor preservation of plasma membrane integrity after fixation in acetone or methanol. Fixation with PF before methanol reduced damage to intracellular and plasma membranes. In addition, Western blot analysis demonstrated loss of Bcl-2 and Bax protein during acetone or methanol fixation, whereas PF fixation before methanol permeabilization markedly reduced this loss. For studies on the intracellular localization of soluble or unknown types of antigen, the authors discourage the use of acetone and methanol as single fixatives.

Acetone↗

PubMed1986

A rapid and simple technique for correlating light microscopy, transmission and scanning electron microscopy of fixed tissues in Epon blocks.

A simplified and standardized technique for close correlation between light microscopy (LM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) is described. Perfusion and immersion fixed tissue specimens were embedded in Epon 812 and cut for conventional LM and TEM. The Epon blocks with remaining tissue were thereafter treated with epoxy solvent (ethanol-NaOH solution) for partial epoxy resin removal only (dissolving rate approx 33 microns/h). The blocks with partially blotted tissue specimens were then critically point dried and gold coated for SEM. This method, in an easy way, allows repeated observations with LM, TEM and SEM with preserved fine structure and exact correlation. Since the technique is so simple and there is no need for special equipment the method can easily be adopted in all laboratories with basic SEM standards.

Animals↗

PubMedDate not supplied

Concerted use of immunologic and ultrastructural analyses in diagnostic medicine: immunoelectron microscopy and correlative microscopy.

Electron microscopy (EM) is a valuable tool in diagnostic medicine, and in some cases, can be enhanced by immunological methods. A major medical application of EM, diagnostic virology, can frequently be augmented by employment of immunological reagents. Three immunoelectron microscopy (IEM) methods, aggregation, coating, and gold labeling, provide means for serotyping viruses; aggregation by antibody can also be used to concentrate viruses in dilute suspension or to serotype them. As a research tool, IEM can be useful in studying the relationship of various pathogen proteins to the infected cells or tissues. Delineating the subcellular location of viral components can yield information about how virions are constructed, and hence, suggest methods and compounds for inhibiting that process. Conversely, labeling virus-infected cells with antibodies against various cell receptors and proteins can yield information about the association of the proteins with budding virions. Another research example is the identification by immunological staining of virus-infected cells for subsequent ultrastructural identification of the specific cell type involved. Electron microscopy and immunolabeling methods are also useful in the diagnosis of immune complex disorders, including various forms of postinfectious immune complex glomerulonephritis. Precise analysis of immune complex deposits can be accomplished by using EM to pinpoint their location and immunohistology to probe their composition. Finally, a variety of optical microscopic techniques, including some involving immunofluorescent labeling, can be used to identify areas of interest in inhomogeneous tissues for further study by EM.

Child↗

PubMed2003

Chronology of cellular alterations during 7-ketocholesterol-induced cell death on A7R5 rat smooth muscle cells: analysis by time lapse-video microscopy and conventional fluorescence microscopy.

BACKGROUND: Time-lapse video microscopy was used to determine whether mitochondrial and nuclear changes (decrease in mitochondrial transmembrane potential, condensation, and/or fragmentation of the nuclei, morphologic features typical of apoptosis) occurring during 7-ketocholesterol-induced cell death on A7R5 rat smooth muscle cells took place before or after the loss of cell adhesion. In addition, changes in actin organization were followed by conventional fluorescence microscopy. METHODS: Morphologic, functional, and spatial changes at the mitochondrial level were investigated with 3,3'-dihexyloxacarbocyanine iodide and/or MitoTracker Red, and nuclear morphology was characterized by staining with Hoechst 33342. Actin fibers, which are major components of the filament network of the cytoskeleton, were visualized with phalloidin linked to fluorescein. The numbers of adherent and nonadherent cells were determined by cell counting. RESULTS: 7-Ketocholesterol-induced cell death was associated with a rapid alteration of actin fibers, a loss of intercellular junctions, and cell shape modifications. Analysis of mitochondrial transmembrane potential showed successively a hyperpolarization and a more or less pronounced progressive decrease followed by a dramatic drop associated with an increase in Hoechst 33342 staining, reflecting chromatin condensation and morphologic changes in the nuclei. CONCLUSIONS: During cell death induced by 7-ketocholesterol in A7R5 rat smooth muscle cells, the different methods of microscopy allowed us to establish that alterations of actin fibers and mitochondrial dysfunctions occurred before condensation and/or fragmentation of the nuclei, which preceded the loss of cell adhesion.

Actins↗

PubMed2005

Refractive index measurement in viable cells using quantitative phase-amplitude microscopy and confocal microscopy.

BACKGROUND: The refractive index (RI) of cellular material provides fundamental biophysical information about the composition and organizational structure of cells. Efforts to describe the refractive properties of cells have been significantly impeded by the experimental difficulties encountered in measuring viable cell RI. In this report we describe a procedure for the application of quantitative phase microscopy in conjunction with confocal microscopy to measure the RI of a cultured muscle cell specimen. METHODS: The experimental strategy involved calculation of cell thickness by using confocal optical sectioning procedures, construction of a phase map of the same cell using quantitative phase microscopy, and selection of cellular regions of interest to solve for the cell RI. RESULTS: Mean cell thickness and phase values for six cell regions (five cytoplasmic and one nuclear) were determined. The average refractive index calculated for cytoplasmic and nuclear regions was 1.360 +/- 0.004. The uncertainty in the final RI value represents the technique measurement error. CONCLUSIONS: The methodology we describe for viable cell RI measurement with this prototype cell has broad generic application in the study of cell growth and functional responses. The RI value we report may be used in optical analyses of cultured cell structure and morphology.

Cell Survival↗