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The Role Of Marrow Architecture And Stromal Cells In The Recovery Process Of Aplastic Marrow Of Lethally Irradiated Rats Parabiosed With Healthy Litter Mates, Keiki Hayashi, Koichi Kagawa, Michiyasu Awai, Shozo Irino

Scanning Electron Microscopy

Bone marrow aplasia was induced in rats by whole body lethal irradiation (1,000 rads by x-ray), and rats died of irradiation injury within 7 days.

Correlative studies at light (LM), transmission (TEM) and scanning electron microscopy (SEM) demonstrated swelling of endothelial and reticular cells and hemorrhage due to detachment of sinus endothelial cells on days 1 and 2. With time, structural recovery occurred without hemopoietic recovery. Reticular cells developed small intracytoplasmic lipid droplets on days 3 and 4. This resulted in fatty a plastic marrow within 7 days. On the other hand, in the marrow of irradiated rats parabiosed with …

Integrated Image And X-Ray Microanalysis Of Hepatic Lysosomes In A Patient With Idiopathic Hemosiderosis Before And After Treatment By Phlebotomy, M. I. Cleton, J. M. Roelofs, C. J. G. Blok-Van Hoek, W. C. De Bruijn

Scanning Electron Microscopy

Morphometrical and X-ray elemental information was extracted from Scanning Transmission Electron Microscopy (STEM) images of hepatic lysosomes of a patient with idiopathic hemosiderosis before and after treatment by phlebotomy. The elements of interest were (i) iron, stored in pathological quantities in hepatic lysosomal structures and (ii) cerium, used as a capture ion after a cytochemical reaction to detect acid phosphatase activity in the lysosomal structures.

Morphologically the lysosomal structures are heteromorph and the elements iron and cerium are heterogeneously distributed. With "reduced raster" (= reduced scanning area) analysis at 16 x 16 pixel points (integrating image and X-ray microanalysis), a …

Structural Features Of Isolated, Fractionated Bone Marrow Endothelium Compared To Sinus Endothelium In Situ, Seiji Irie, Mehdi Tavassoli

Scanning Electron Microscopy

Structural features of isolated, fractionated rat bone marrow endothelium were compared to those of marrow sinus endothelium in situ. Marrow endothelium was purified, first by density gradient sedimentation on Percoll and then subjected to centrifugal elutriation. Using antifactor VIII antibody staining (indirect immunofluorescent method), preparations of greater than 50% purified endothelium were obtained. By SEM, these cells were about 10 μm in size and showed smooth surface and numerous invaginations. These features were also observed in the in situ endothelium obtained by perfusion-fixation and freeze-cracking. In addition, in situ endothelium displayed numerous hemopoietic cells in migration through the endothelium. By …

Cell Ultrastructure In Disease, R. Laschi, E. Govoni

Scanning Electron Microscopy

The doctor of today must adopt the 'cellular way of thinking' in the evaluation of diseases. This ultrastructural outlook provides him with much indispensable information that also serves a practical purpose. A diseased cell organelle is at the basis of every clinical sign and any attempt of therapy must be aimed at that specific point of lesion. We intend, in the light of a long experience, to propose to clinicians a new way of thinking in which a precise correlation between symptoms and sub-microscopic changes of the cell is considered. Many different examples amply justify this proposal. Electron microscopy can …

An Organic Reference Specimen: Polyacrylonitrile Film Deposited On Oxidizable Metals By Electro-Polymerization, C. Boiziau, G. Lécayon

Scanning Electron Microscopy

Surface investigations of organic materials require the provision of reference specimens for calibrating experimental equipment.

Because of their specific properties (purity, reproducibility, well-known molecular structure and orderly inter-molecular structure, electronic properties associating conductive and insulating behaviour, quality of the film-to-metal bound), polyacrylonitrile films obtained through electro-polymerization on oxidizable metal cathodes (Fe, Ni, Cu) may be used as a first type of reference sample.

Experimental results, obtained by various surface investigation techniques are presented, and their validity evaluated.

Simulation With Pharmacological Agents Of Radiation Damage To Small Intestinal Villi, M. Indran, F. C. Boyle, K. E. Carr

Scanning Electron Microscopy

Irradiation induces damage to intestinal villi, resulting in a progressive decline in villous height and changes in topography. Gamma and neutron radiation are reported to cause changes in the structure of smooth muscle and nerve twigs of the intestinal wall. It is possible, therefore, that villous collapse may be due partly to changes in the underlying stromal elements as a result of damage to nerve or muscle.

To test this hypothesis, mice were treated with the drug reserpine which is known to affect the neural control of intestinal smooth muscle function and the small intestine was examined for topographical and …

Application Of Chelex Standard Beads In Integrated Morphometrical And X-Ray Microanalysis, W. C. De Bruijn, M. I. Cleton-Soeteman

Scanning Electron Microscopy

Chelex ion exchange beads loaded with a known amount (18.3% weight percentage (w/w)) of platinum, have been co-embedded with a mouse peritoneal cell population. To establish the influence of the various deconvolution methods applied, upon the platinum concentration in cytoplasmic granules and erythrocytes these cross-sectioned beads are used as a standard. It is concluded that irrespective of the deconvolution method chosen 1) the Pt concentration inside the particles is identical when the particles and the co-embedded Chelex Pt standard, are analysed strictly under the same instrumental conditions 2) the Pt concentration outside the particle is zero, or virtually zero when …

Reduction Of Electron Beam Induced Radiation Damage Of Organic Material By Cooling To 4 K (Cryo Electron Microscopy), I. Dietrich, E. Knapek, G. Lefranc

Scanning Electron Microscopy

Structure investigations of organic, in particular biological, material are frequently performed with a strong electron beam. If the dose is higher than le/Ų, as required e.g. for high resolution electron microscopy, the results are strongly influenced by radiation damage. There are no means for preventing breaking of chemical bonds and ionizing of atoms and fractures of molecules due to the electron impact. The secondary processes, however, such as diffusion or evaporation of the fragments, can be strongly reduced by cooling the specimen to 4 K (cryoprotection). A suitable instrument for experimenting with cryoprotection is a microscope equipped with …

Monte Carlo Calculations For Electron Microscopy, Microanalysis, And Microlithography, David F. Kyser

Scanning Electron Microscopy

The methodology of Monte Carlo simulation for electron scattering and energy dissipation in solid targets is reviewed. The basic concepts of single and multiple elastic scattering models are compared, and the continuous energy loss model for inelastic scattering is discussed. Some new developments in Monte Carlo simulation are reviewed, including improvements in the elastic scattering model and discrete models for inelastic scattering. A variety of practical applications of Monte Carlo calculations in the fields of electron microscopy, electron probe microanalysis, and electron beam lithography are reviewed. The Monte Carlo computer program listings available in the literature are also described.

Monte Carlo Calculations On The Spatial And Angular Distributions Of High Energy Electron Beams In Amorphous And Polycrystalline Films, J. L. Balladore, J. P. Martinez, J. Trinquier, B. Jouffrey

Scanning Electron Microscopy

We study the plural scattering of electrons in amorphous and polycrystalline films. The incident electron energy ranges from 0.1 to 3 MeV. The cross sections are obtained by measuring the transmission coefficient for targets of gold, silver, aluminium and carbon. The partial elastic cross section is calculated from Lenz's theory using a Wentzel-Yukawa model for the atomic potential of the scattering atom. In the case of inelastic interactions, we take into account either scattering by a free atom (Morse's approximation) or scattering by plasmon creation (relativistic theory of Ashley Ritchie). From these results, we solve the problem of electron transport …