Search results for "Microscopy"
showing 10 items of 3390 documents
Bimodal Oscillation Frequencies of Blood Flow in the Inflammatory Colon Microcirculation
2008
Rhythmic changes in blood flow direction have been described in the mucosal plexus of mice with acute colitis. In this report, we studied mice with acute colitis induced either by dextran sodium sulfate or by trinitrobenzenesulfonic acid. Both forms of colitis were associated with blood flow oscillations as documented by fluorescence intravital videomicroscopy. The complex oscillation patterns suggested more than one mechanism for these changes in blood flow. By tracking fluorescent nanoparticles in the inflamed mucosal plexus, we identified two forms of blood flow oscillations within the inflammatory mouse colon. Stable oscillations were associated with a base frequency of approximately 2 …
Ribbon synapses of the mammalian retina contain two types of synaptic bodies--ribbons and spheres.
1989
The present paper reports that the synaptic bodies of the retinal ribbon synapses in rat, guinea pig, golden hamster and mouse are a heterogeneous population of organelles. In addition to the well-known synaptic ribbons sensu stricto which consist of a platelike electron-dense central structure surrounded by electron-lucent synaptic vesicles, there are what is termed synaptic spheres, in which the core is not platelike, but round to oval. In rat retinae procured at day, ribbons outnumbered spheres by a factor of 4. At night spheres were not seen in photoreceptor cells. Spheres, like ribbons, may lie some distance from the synaptic site, perhaps indicating transit from their site of origin t…
Spatial calibration of structured illumination fluorescence microscopy using capillary tissue phantoms.
2008
Quantitative assessment of microvascular structure is relevant to the investigations of ischemic injury, reparative angiogenesis and tumor revascularization. In light microscopy applications, thick tissue specimens are necessary to characterize microvascular networks; however, thick tissue leads to image distortions due to out-of-focus light. Structured illumination confocal microscopy is an optical sectioning technique that improves contrast and resolution by using a grid pattern to identify the plane-of-focus within the specimen. Because structured illumination can be applied to wide-field (nonscanning) microscopes, the microcirculation can be studied by sequential intravital and confocal…
Loss of desmoglein 2 suggests essential functions for early embryonic development and proliferation of embryonal stem cells.
2002
Summary Desmoglein 2 (Dsg2) is a Ca 2+ -dependent adhesion molecule of desmosomes and is synthesized in all desmosome-bearing tissues from their earliest appearance onward. To examine the function of Dsg2, its gene was inactivated by homologous recombination in embryonal stem (ES) cells for the generation of knockout mice. DSG2 −/− mice and a considerable number of DSG2 +/− mice died at or shortly after implantation. On the other hand, DSG2 −/− blastocysts developed an apparently normal trophectoderm layer, the first tissue known to produce desmosomes, and hatched properly. Immunofluorescence analyses of these blastocysts showed, however, that the distribution of the desmosomal plaque prote…
Adaptation of the disector method to rare small organelles in TEM sections exemplified by counting synaptic bodies in the rat pineal gland
1997
The disector is the only objective method for quantifying particles of variable size in a given volume. With this method, cell organelles are identified on adjacent sections, but only those present in one section are counted. When counting extremely rare structures in transmission electron microscope sections (physical disector), the usual procedure of counting on electron micrographs is limited for economic reasons (e.g. micrographs highly outnumbering the investigated structures). Hence, to apply this unbiased stereological method, a modification of the physical disector concerning 3 aspects has been developed. (1) The prerequisite of screening large corresponding tissue areas (here appro…
Stage-specific chromosomal association of Drosophila dMBD2/3 during genome activation.
2002
The Drosophila gene dMBD2/3 encodes a protein with significant homologies to the mammalian methyl-DNA binding proteins MBD2 and MBD3. These proteins are essential components of chromatin complexes involved in epigenetic gene regulation. Because the available in vitro data on dMBD2/3 are conflicting we have started an in vivo characterization of dMBD2/3. We detected expression of two isoforms specifically during embryonic development. Staining of whole embryos combined with high-resolution confocal microscopy revealed a highly regulated spatial distribution. During the syncytial blastoderm stage, dMBD2/3 formed speckles that localized to the cytoplasm. Shortly after, during the cellular blas…
Immunocytochemistry of M-cadherin in mature and regenerating rat muscle
1994
Background: Cadherins are transmembrane proteins mediating calcium-dependent cell–cell adhesion in a cell type-specific manner by means of homophilic binding. M(muscle)-cadherin is a recently detected member of the cadherin family. Methods: We have investigated the localization of M-cadherin innormal and aneurally regenerating skeletal muscle of rat by means of pre-embedding immunocytochemistry. The antibody was directed against the extra-cellular domain of M-cadherin. Results: Myoblasts and myotubes in regenerating muscles tended to be arranged in clusters enclosed by a common basal lamina. Satellite cells of mature muscle fibers were attached to the underlying fiber without separating bas…
Quantitative Spatial Analysis of the Mouse Brain Lipidome by Pressurized Liquid Extraction Surface Analysis
2014
Here we describe a novel surface sampling technique termed pressurized liquid extraction surface analysis (PLESA), which in combination with a dedicated high-resolution shotgun lipidomics routine enables both quantification and in-depth structural characterization of molecular lipid species extracted directly from tissue sections. PLESA uses a sealed and pressurized sampling probe that enables the use of chloroform-containing extraction solvents for efficient in situ lipid microextraction with a spatial resolution of 400 μm. Quantification of lipid species is achieved by the inclusion of internal lipid standards in the extraction solvent. The analysis of lipid microextracts by nanoelectrosp…
Ruthenium red staining of polyanion containing structures in sections from epoxy-resin embedded tissues
1984
Summary Staining by ruthenium red (0.5 mg/ml in borate buffer at pH = 9.2) has been used for light and electron microscopic visualization of polyanion containing structures in sections from glutaraldehyde-fixed, epoxy-embedded tissues. This staining technique can be applied in a simple and rapid way, showing the reactive cell components with suitable resolution and contrast. Preliminary spectrophotometric studies show the correspondence in absorption characteristics of the dye which is bound to polyanions in situ or in vitro .
Ultrastructure and formation of the physogastric termite queen cuticle
1982
0040-8166 (Print) Journal Article; The physogastric termite queen is the most striking example in insects of growth in size without cuticular moulting. This phenomenon has been studied with electron microscopy and histochemical tests in two species of higher termites, Cubitermes fungifaber and Macrotermes bellicosus. The abdominal hypertrophy (physogastry) is allowed by growth of the arthrodial membranes of the swarming imago. The growth is slow (over several years) but important: the cuticular dry weight is multiplied by 20 in C. fungifaber, by 100-150 in M. bellicosus. The termite queen cuticle arises from the transformation of the cuticle of the swarming imago or imaginal cuticle (unfold…