Search results for "Microscopy"
showing 10 items of 3390 documents
Evaluation of the healing of precoated vascular dacron prostheses.
1991
Knitted and woven Dacron grafts commercially coated with bovine collagen, gelatin and human albumin were implanted end-to-side between the infrarenal aorta and the bifurcation in 35 growing pigs. Grafts were explanted after 4, 8 and 12 weeks and compared to 6 uncoated knitted prostheses preclotted with blood that served as a control. Uncoated grafts rapidly developed a firmly attached neointima lined with endothelium. Compared with coated grafts the thrombus-free area of uncoated grafts was significantly larger (P less than 0.05). The slow resorption of albumin resulted in a delayed and incomplete neointimal healing and failing graft incorporation. Although the bovine collagen was only mini…
The fine structure of de-and reinnervated muscle spindles
1974
Reinnervated muscle spindles in lower lumbrical muscles of rats studied 17 days to 24 months after crushing the sciatic nerve showed a series of alterations which have not been analysed, thus far, by electron microscopy. There was a striking increase of the number of intrafusal muscle fibers seen in approximately 20% of reinnervated spindles. These spindles showed 5–11 intrafusal muscle fibers whereas normal spindles usually contained 3–4 fibers only.
Integration of complex larval chemosensory organs into the adult nervous system ofDrosophila
2003
The sense organs of adult Drosophila, and holometabolous insects in general, derive essentially from imaginal discs and hence are adult specific. Experimental evidence presented here, however, suggests a different developmental design for the three largely gustatory sense organs located along the pharynx. In a comprehensive cellular analysis, we show that the posteriormost of the three organs derives directly from a similar larval organ and that the two other organs arise by splitting of a second larval organ. Interestingly, these two larval organs persist despite extensive reorganization of the pharynx. Thus, most of the neurons of the three adult organs are surviving larval neurons. Howev…
Engineered axon tracts within tubular biohybrid scaffolds
2021
[EN] Injuries to the nervous system that involve the disruption of axonal pathways are devastating to the individual and require specific tissue engineering strategies. Here we analyse a cells-biomaterials strategy to overcome the obstacles limiting axon regeneration in vivo, based on the combination of a hyaluronic acid (HA) single-channel tubular conduit filled with poly-L-lactide acid (PLA) fibres in its lumen, with pre-cultured Schwann cells (SCs) as cells supportive of axon extension. The HA conduit and PLA fibres sustain the proliferation of SC, which enhance axon growth acting as a feeder layer and growth factor pumps. The parallel unidirectional ensemble formed by PLA fibres and SC …
Practical application of electron microscopy to neuromuscular diseases.
2013
Concerning individual neuromuscular conditions, electron microscopy may be considered “essential,” “helpful,” or “wasteful.” “Essential” electron microscopy should provide a clear diagnosis, because of the disease specificity of the ultrastructural findings, in particular as to inclusions within muscle fibers, such as cylindrical spirals and reducing bodies. Electron microscopy may be “helpful” in detecting ultrastructural features preceding typical light microscopic findings, for instance, undulating tubules in endothelial cells. Congenital, metabolic, and inflammatory myopathies may often be more easily and more reliably diagnosed by means of the electron microscope. Diagnostically “waste…
FRET based ratiometric Ca(2+) imaging to investigate immune-mediated neuronal and axonal damage processes in experimental autoimmune encephalomyeliti…
2015
Abstract Background Irreversible axonal and neuronal damage are the correlate of disability in patients suffering from multiple sclerosis (MS). A sustained increase of cytoplasmic free [Ca2+] is a common upstream event of many neuronal and axonal damage processes and could represent an early and potentially reversible step. New method We propose a method to specifically analyze the neurodegenerative aspects of experimental autoimmune encephalomyelitis by Forster Resonance Energy Transfer (FRET) imaging of neuronal and axonal Ca2+ dynamics by two-photon laser scanning microscopy (TPLSM). Results Using the genetically encoded Ca2+ sensor TN-XXL expressed in neurons and their corresponding axo…
Morphological aspects of the neuronal ceroid lipofuscinoses
2000
Morphological aspects of the neuronal ceroid lipofuscinoses (NCL) encompass two main features: loss of nerve cells and accumulation of autofluorescent lipopigments within cellular compartments. The former requires histology and morphometry for assessment, while the latter necessitates fluorescence microscopy, electron microscopy, and immunohistochemistry. Accumulation of lipopigments is widespread throughout the central nervous system and extracerebrally. The latter feature enables diagnosis of NCL and its clinical subtype. Loss of neurons is most pronounced in cerebral and cerebellar cortices, in early childhood forms. In subcortical grey matter and in later-onset forms, juvenile and adult…
Supravital Uptake of Cationic Dyes by Mast Cell Granules: A Light and Electron Microscope Study
1994
Methylene blue and neutral red were selected for staining mast cell granules by supravital injections. A new technique was applied for embedding in paraffin and Araldite without dislocation or loss of dye. Stabilization and electron microscopic identification of the dyes were achieved by transforming them into electron-dense precipitates using phosphomolybdic acid dissolved in a paraformaldehyde-glutaraldehyde mixture to preserve the ultrastructure of the tissues. It was found that in general the intensity of the light microscopic staining correlated directly with the electron density. Closer study revealed that not all cytoplasmic granules exhibited the same strong affinity for the cationi…
Magnetoelectric coupling driven by inverse magnetostriction in multiferroic BiMn3Mn4O12
2013
By means of neutron powder diffraction, we investigated the effect of the polar Bi$^{3+}$ ion on the magnetic ordering of the Mn$^{3+}$ ions in BiMn$_3$Mn$_4$O$_{12}$, the counterpart with \textit{quadruple} perovskite structure of the \textit{simple} perovskite BiMnO$_3$. The data are consistent with a \textit{noncentrosymmetric} spacegroup $Im$ which contrasts the \textit{centrosymmetric} one $I2/m$ previously reported for the isovalent and isomorphic compound LaMn$_3$Mn$_4$O$_{12}$, which gives evidence of a Bi$^{3+}$-induced polarization of the lattice. At low temperature, the two Mn$^{3+}$ sublattices of the $A'$ and $B$ sites order antiferromagnetically (AFM) in an independent manner …
Electronmicroscopical Contrast by Palladium Chloride
1986
Thin sections of glutaraldehyde-fixed, epoxy resin-embedded bone marrow from rats were treated with 2% palladium chloride in 2% concentrated HCl. This procedure was found to induce high electron density in chromatin from all cell types and in cytoplasmic granules of neutrophils and eosinophils. In the latter, the crystalline body showed more contrast than the matrix.