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Microvillus Form Of Focal Anchorage In Human Chang Liver Cells Rounded By Antiporter Activation: Scanning Electron Microscopy Profiles And Evidence Of Traction Origin, K. H. Sit, B. H. Bay, K. P. Wong

Scanning Microscopy

Na⁺/H⁺ anti porter activation in human Chang liver cells produces a flat-to-round (FTR) change in cell shape with gross reduction in cell profile area. Scanning electron microscopy (SEM) vividly displays a third phenomenon, viz., the development of focal microvillus anchors. Reduction in cell profile area concomitant with the development of this microvillus form of focal anchorage is quantitated by on-line image analysis during SEM examination. The reduction in profile area is corroborated by spectrophotometric digitization in light microscopy. Transmission electron microscopy (TEM) of rounded cells shows large endocytic channels and endosomes consistent with the observation of internalization …

Fluorescence Recovery After Photobleaching Techniques To Measure Translational Mobility In Microscopic Samples, Ken Jacobson, Fen Zhang, Tsong-Tseh Tsay

Scanning Microscopy

The scope of photobleaching applications and the method itself are briefly reviewed. Two current applications in this laboratory are then outlined. First, the use of spatial Fourier transforms to analyze video photobleaching measurements is presented. This method extracts diffusion coefficients using all the image data and it does not require that the initial condition created by photobleaching be known. Second, the use of genetic engineering methods coupled with photobleaching analysis is discussed as means to uncover the structural determinants of membrane protein lateral mobility.

Three-Dimensional Morphology Of Cerebellar Protoplasmic Islands And Proteoglycan Content Of Mossy Fiber Glomerulus: A Scanning And Transmission Electron Microscope Study, O. J. Castejón, H. V. Castejón

Scanning Microscopy

The present review summarizes the outer and inner surface features of mossy fiber glomeruli in vertebrate cerebellar granular layer as seen by conventional scanning electron microscopy (SEM) and SEM freeze-fracture method. The intracortical trajectory of mossy fibers and their synaptic contacts with granule cell dendrites were traced by the slicing and freeze-fracture techniques revealing the radial distribution of granule cell dendrites around the central mossy rosette. The "en passant" nature of mossy fiber synaptic contacts and the participation of Golgi cell axonal ramifications were demonstrated. The results obtained were compared with available light and transmission electron microscopy data. The freeze-etching …

Alpha-Particle Irradiation-Induced Change In Bronchopulmonary Macrophage Morphology, In Vitro, T. M. Seed, G. K. Niiro

Scanning Microscopy

Bronchopulmonary macrophages, isolated from canine lungs by saline lavage and grown in tissue culture for short periods, were acutely irradiated with a range of doses of either Americium-241 alpha particles (0.03-48 Gy) or 250 keV x-rays (0.5-24 Gy). Following a 24-hour reincubation and "expression" period, cells were examined for radiation-induced changes in overall viability, as well as in cell morphology and ultrastructure. Results indicated that neither quality of radiation had much effect on cell viability over dose ranges examined, but substantial changes in cell volume, surface topography, and cytoplasmic features were noted, especially in the alpha-particle-irradiated specimens. Results support the …

A Scanning Electron Microscopic Morphological And Semi-Quantitative Evaluation Of Rat Stomach Treated With Colloidal Bismuth Subcitrate And Alcohol, C. Winters, S. M. Hinsull, Z. Gregory

Scanning Microscopy

Scanning electron microscopy was utilised to study the effect of absolute alcohol on the normal morphology of the rat stomach, together with the gastroprotective actions of colloidal bismuth subcitrate. Studies on normal gastric morphology revealed that the major portion of the stomach was covered by a protective coating of mucus. However, there was considerable variation in the integrity of the mucosal surface of the control animals, with the loss of surface epithelial cells in some regions which may account for the variation in response to necrotising agents. The long-term administration of the gastrocytoprotective agent colloidal bismuth subcitrate resulted in a …

The Response Of The Tracheal Epithelium To Concomitant Cis-Diamminedichloroplatinum (Ii) And Radiation. An Electron Microscopic Study In Rabbits, C. H. Håkansson, M. Albertsson, M. Palmegren, J. Ranstam

Scanning Microscopy

The ciliated epithelium of the rabbit trachea was irradiated with daily fractions of 2 Gy up to an accumulated dose of 20 Gy (total dose: 2, 6, 10, 16, or 20 Gy). Fifteen to forty-five minutes before the start of each irradiation 0.3 mg Cis-diamminedichloroplatinum (cis-DDP) was given by intraperitoneal injection to each rabbit. Examinations were carried out 1-10 days after each fractionation schedule, when specimens were taken for morphological investigations.

Scanning electron microscope (SEM) examination showed a gradual development of ciliary damage, from blebs on the cilia to swollen tips, broken and bent cilia and finally an epithelial injury …

Timed Acid Bath Effects On Kidney Podocytes Prepared For Scanning Electron Microscopy, B. J. Moore, K. R. Holmes

Scanning Microscopy

In perfusion fixation of dog kidney glomeruli, observation of tear fractured surfaces by scanning electron microscopy reveals the deposition of "debris" on the surface of glomerular visceral epithelium (podocytes) that is not deposited on other kidney tissue surfaces. It is of concern to remove this debris without damage to tissue surfaces. A 5 minute bath in 8N HCI (hydrochloric acid) following postfixation in 1% OsO₄ (osmium tetroxide) removes only some of the debris. A 10 minute acid bath removes this debris without visible damage to podocyte surface structures such as cilia, plicae or blebs. A 20 minute acid bath …

Transplacental Cardiotoxicity Of Cocaine: Atrial Damage Following Treatment In Early Pregnancy, Jacques Gilloteaux, John P. Dalbec

Scanning Microscopy

Using light, transmission (TEM) and scanning (SEM) electron microscopy, cocaine-induced defects were observed in hamster atria. Compared with controls, the treated atria from neonates show endocardial and myocardial damages as the atrial walls thicken. SEM micrographs show intensive blebbing, damage and incomplete coverage of myocardium by the endocardial endothelium. TEM data demonstrate blebs, thinning, and other endothelial cell injuries and complement the SEM findings. Areas of endothelial sloughing may facilitate the formation of luminal and mural thrombi as noticed in many neonatal atria. Adjacent subendocardial myocardial cells display contraction bands, swellings, and vacuolizations. Local and large areas of damaged myocardial …

Copper Toxicity In Erwinia Amylovora : An X-Ray Microanalytical Study, N. Hodson, D. C. Sigee

Scanning Microscopy

The effect of Cu²⁺ ions on the growth and elemental composition of the phytopathogenic bacterium Erwinia amylovora was investigated by in vitro culture in nutrient broth supplemented with CuSO₄.

No detectable inhibition in bacterial growth occurred with medium supplemented at 10^-4M Cu (compared to control medium with no added Cu), but partial inhibition occurred at 10^-3M Cu (limiting toxicity) and complete inhibition at 10^-2M Cu.

Under conditions of limiting toxicity, incubation in Cu²⁺ ions leads to a reduction in the general synthesis of cell materials and the formation of abnormally …

An Introduction To Monte Carlo Simulations, David C. Joy

Scanning Microscopy

The interaction of an electron beam with a solid can be modeled by the so-called Monte Carlo method. This technique produces a stepwise simulation of the electron trajectory by using random numbers to predict scattering angles on the basis of theoretical probability distributions or empirical models. The physical basis of electron scattering in a solid is described and two generic types of Monte Carlo model are then developed together with suggested examples of their application. An IBM PC compatible disc containing these programs is available from the author.

Phenomena Relating To Charge In Insulators: Macroscopic Effects And Microscopic Causes, Jacques Cazaux, Claude Le Gressus

Scanning Microscopy

Conservation of current under steady-state conditions makes it possible to determine the sign of charges trapped in an insulator subjected to ionizing radiation. The maximum value of the surface potential can thus be estimated.

On the basis of a given trapped charge distribution, the pattern of the electrical field and of the potential can thus be established, and the influence of the shape of the sample and its environment can be clearly shown. Change of trapped charges with time (at the start and after irradiation) is then examined. Finally, the microscopic causes of trapping of charge is suggested by analogy …

Imaging Of Magnetic Microstructures At Surfaces: The Scanning Electron Microscope With Spin Polarization Analysis, H. P. Oepen, J. Kirschner

Scanning Microscopy

The scanning electron microscope with spin polarization analysis of secondary electrons has been proven to be a powerful tool for studying magnetic microstructures. Secondary electrons created at the surface of a ferromagnet are spin-polarized and contain information about the sample magnetization and its orientation. The combination of a spin polarization analyzer with a scanning electron microscope yields an unique apparatus for probing magnetic properties on a very small lateral scale. The magnetic resolution of < 40 nm is demonstrated. This type of microscope provides high magnetic contrast, while the surface morphology is strongly or even totally suppressed. The capability of studying magnetic properties of semi- infinite samples as well as in ultrathin films is demonstrated with a Fe(lOO) single crystal, video tape, CoCr perpendicular recording medium and ultrathin cobalt films.

Effects Of Low Energy Beta-Irradiation From Tritiated Water On The Morphology Of 3t3 Fibroblasts, Z. Somosy, Tamara Kubasova, J. Kovács, G. J. Köteles

Scanning Microscopy

Cellular alterations of cultured 3T3 cells irradiated with beta-rays from tritiated water were studied by scanning and transmission electron microscopy. We observed decreased negative surface charges, vacuolization of rough endoplasmic reticulum and Golgi-complex, degeneration of mitochondria, increase of lysosomal activity and changes in distribution and amount of microfilaments in the irradiated cells, that parallelled changes in cell shape.

Physicochemical And Macromolecular Properties Of Starch-Cellulose Fiber Extrudates, R. Chinnaswamy, M. A. Hanna

Food Structure

Three different pure cellulose fibers (James River Corporation, NJ) with lengths of 22, 60 and 110 pm were used at 1, 2, 4, 6, 8 and 10% concentrations with normal corn starch. The fiber-starch mixtures were extruded (C.W. Brabender Laboratory Extruder) at moisture contents of 14, 18 and 22% (db), 140°C barrel temperature and 140 rpm screw speed. The expansion ratio of the starch-fiber extrudates varied from 5.0 to 13.3. The maximum expansion ratio of 13.3 was obtained with 2%-60 mm fiber and 14% (db) moisture content. Increasing fiber concentration and moisture content generally reduced the expansion volumes. Water solubility …

Accuracy In Forecasting: The Results Of A Competition, Rhonda K. Skaggs, Donald L. Snyder

Economic Research Institute Study Papers

No abstract provided.

Structures And Properties Of Stabilized Vitamin And Carotenoid Dry Powders, Victor E. Colombo, Francoise Gerber

Food Structure

The development of special formulated forms of vitamin and carotenoid dry powders solved most of the technical problems encountered in handling the original pure crystalline or oily compounds. Various procedures to obtain stabilized products have been introduced on an industrial scale for feed , food and pharmaceutical purposes. Proven modes of manufacture of formulated dry powders includes the numerous spraying processes for emulsions, dispersions or solutions, and the production of adsorbates of fat-based products.

The objective of this paper is to provide an overview of stabilized vitamin and carotenoid dry powders. This contribution is intended to demonstrate the usefulness of …

Peripheral Nerve Bridges For Central Nervous System Regeneration, Silvio Varon, Theo Hagg, H. Lee Vahlsing, Marston Manthorpe

Cells and Materials

A neuronotrophic hypothesis for the adult central nervous system (CNS) has been increasingly supported by in vivo studies of Nerve Growth Factor (NGF) impacts on adult rat CNS cholinergic neurons. We have extended these investigations to NGF effects on cholinergic axonal regeneration in an adult rat septo-hippocampal model. A fimbriafornix lesion deprives the dorsal hippocampal formation (HF) of its cholinergic afferents and provides a cavity into which sciatic nerve segments can be implanted to serve as regeneration bridges from septum to HF. Septa! cholinergic fibers enter and course through fresh cell-containing nerve bridges to attain a maximal number by the …

Primary Bone Formation In Porous Hydroxyapatite Ceramic: A Light And Scanning Electron Microscopic Study, M. Okumura, H. Ohgushi, S. Tamai, E. C. Shors

Cells and Materials

Porous hydroxyapatite ceramics combined with rat marrow cells were implanted subcutaneously in the back of syngeneic Fischer rats . Fluorochrome-labeling (calcein, tetracycline) was performed post-operatively and the ceramics were harvested 4 weeks after implantation. Undecalcified thin sections of the implants were observed under light microscopy or fluoromicroscopy and the corresponding areas were also analyzed in a scanning electron microscope connected to an electron probe microanalyzer (SEM-EPMA). Many pore areas of the ceramics showed bone and osteoid formation together with active osteoblasts. The bone formation began directly on the surface of the ceramic and proceeded in a centripetal direction towards the …

Deposition And Resorption Of Calcified Matrix In Vitro By Rat Marrow Cells, J. E. Davies, R. Chernecky, B. Lowenberg, A. Shiga

Cells and Materials

Rat bone marrow derived cells were cultured using a-Minimal Essential Medium supplemented with antibiotics, ascorbic acid and !3-glycerphosphate in the presence of 10-8M dexamethasone, on polystyrene and hydrophilic fluorocarbon substrata for periods of 2 - 4 weeks. During this time, a large yield of bone nodules was achieved and the elaborated tissue was examined by both scanning and transmission electron microscopy. The matrix produced by the cells contacting the underlying substratum was an afibrillar, globular, calcified material which formed a layer approximately 0.5μm thick. The calcium and phosphorus content of this material was confirmed by energy dispersive X-ray dot mapping …

Analysis Of Protein Adsorption On Retrieved Human Vascular Grafts Using Immunogold Labelling With Silver Enhancement, N. P. Ziats, N. S. Topham, D. A. Pankowsky, J. M. Anderson

Cells and Materials

The adsorption of proteins on biomedical materials such as vascular grafts is important in modulating thrombosis, one eventual cause of vascular graft failure. We have identified proteins expressed on the surfaces of retrieved vascular grafts to determine if certain proteins were present at the end stage of vascular failure. Scanning electron microscopic analysis of protein adsorption on the surfaces of retrieved vascular prostheses was determined using antibodies to human blood proteins fibrinogen, fibronectin, Hageman factor (factor XII) and factor VIII/von Willebrand Factor. The detection of these proteins on the blood contacting surface was evaluated by immunogold labelling with protein A-gold …

Calcification Of Rat Valve Allografts, Flavian M. Lupinetti, Sandra Cobb, Hans C. Kioschos, Sue Ann Thompson, Katherine S. Walters, Kenneth C. Moore

Cells and Materials

Scanning electron microscopy (SEM) and energy dispersive X-ray microanalysis (EDS) have been used to quantify calcium deposition in bioprosthetic valves. To further characterize the calcification process as it pertains to allograft valve tissue, two models of tissue valve implantation were used. The first model used subcutaneous implantation of glutaraldehyde-preserved allogeneic aortic and pulmonary valve leaflets. The second model used syngeneic or allogeneic fresh aortic valve grafts implanted heterotopically into the abdominal aorta of recipient rats. Reference light microscopy was used to select sections for SEM and EDS. In the subcutaneous model, calcium content in both the pulmonary and aortic valves …

Scanning Electron Microscopic Evaluation Of The Fractured Surfaces Of Canine Calculi From Substrata With Different Surface Free Energy, H. M. W. Uyen, W. L. Jongebloed, H. J. Busscher

Cells and Materials

The strength of adhesion between dental calculus and enamel or dentin surfaces determines the ease with which the calculus can be removed by brushing or professional dental treatment. In this study, we examined the adhesion of canine calculi formed on substrata with different surface free energies (sfe) and roughness by means of scanning electron microscopy. In 4 beagle dogs fenestrated crowns were made on the upper fourth premolars. Subsequently, facings of glass (sfe = 120 mJ. m-2), bovine enamel (sfe = 85 mJ.m-2), bovine dentin (sfe = 92 mJ.m-2), polymethyl-methacrylate (PMMA, sfe = 56 mJ.m-2) and polytetrafluorethylene (PTFE, sfe = …

Polylysine Stimulation Of Ectopic Cartilage Formation, Rocky S. Tuan, Dina M. Turchi, David S. Kreitzer

Cells and Materials

Cartilage development, or chondrogenesis, is a process which involves the condensation of prechondrogenic mesenchymal cells, followed by the expression of the cartilage phenotype characterized by the biosynthesis of cartilage-specific, extracellular matrix components. We have previously shown that the cationic biopolymer, polylysine (PL), is able to stimulate chondrogenesis by embryonic limb bud mesenchymal cells in vitro. In this study, we have evaluated the chondrogenesis-stimulating activity of PL in vivo using an experimental system consisting of chick embryonic muscle explants, which were grafted onto the chorioallantoic membrane of chick embryos maintained in long-term shell-less culture. The muscle grafts were treated with PL …

A Versatile, Low Toxicity Glycol Methacrylate Embedding Medium For Use In Biological Research, And For Recovered Biomaterials Prostheses, Peter O. Gerrits, Bernhard Eppinger, Harry Van Goor, Richard W. Horobin

Cells and Materials

Methods for preparing standardized glycol methacrylate (GMA) based embedding media for use in light microscopy in a rational, precise and reproducible manner are described. The application of these procedures resulted in a versatile, low toxicity GMA embedding medium.

GMA embedding medium and resin blocks were tested utilizing a variety of physico-chemical techniques, namely: gas chromatography, determination of the maximum temperature reached during polymerization, the time taken to reach the maximum temperature, hardness testing, determination of the glass transition temperature, and measurement of the dimensional changes following section stretching and mounting at various temperatures. Data obtained from these techniques enabled a …

Fracture Toughness And Fractography Of Dental Ceramics, H. J. Mueller

Cells and Materials

Chevron-notch short-rod fracture toughness (KIv) and scanning electron microscopy analyses of leucite-, tetrasilicic fluormica-, and alumina- reinforced dental ceramics and control materials were investigated. Short-rod fracture toughness is a measure of the bulk resistance to crack propagation but not of the surface resistance to crack initiation. Results indicated significant differences in KIv among the following six groups (from lowest to highest (a) Dicor and Optec, (b) Optec, Excelco's Incisal, Macor and Excelco's Gingival, (c) Excelco's Brush-O-Paque, (d) Vitadur-N core, (e) Coming's 9606 glass-ceramic, and (t) Vita Hi Ceram. Good agreement occurred with published data for Macor and 9606. Comparisons of …

Structure And Rheology Of Dairy Products: A Compilation Of References With Subject And Author Indexes, David N. Holcomb

Food Structure

No abstract provided.

Effect Of Irradiation And Dielectric Heating On Soybean Ultrastructure, Trypsin Inhibitor, And Lipoxygenase Activities, E. Kovacs, N. D. Lam, J. Beczner, I. Kiss

Food Structure

Scanning electron microscopy ( SEM) was used to observe the protein bodies of soybeans after irradiation (0 - 10 kGy dose range) , dielectric heating and storage . Microbiological changes , lip oxygenase and trypsin inhibit or activities and biological value were also studied after different treatments and storaee . There were no differences in the ultrastructure of control and irradiated ( 3, 6 and 10 kGy) soybeans immediately after irradiation . The effect of storage depended on whether whole or milled soybeans had been stored . There was no direct effect of dielectric he ating on soybeans ultrastruc ture …

Effect Of Extruder Die Temperature On Texture And Microstructure Of Restructured Mechanically Deboned Chicken And Corn Starch, V. B. Alvarez, D. M. Smith, S. Flegler

Food Structure

Proximate composition, textural properties and microstructural changes of mechanically deboned chicken/15% corn starch extrudates were evaluated when restructured at die temperatures of 25, 71, 82, 93 , 104 and ll5°C in a twin-screw extruder. Total sol ids and fat content decreased, whereas protein content increased die temperatures were increased. When die temperature was increased from 71°C to 104°C, apparent stress at failure of extrudates increased by 44 kPa , but decreased at a die temperature of 115°C. Changes in the protein matrix, fat globules and starch granules due to changes i n extruder die temperature were observed by scanning electron …

Immunohistochemical Techniques Applied To Raw And Mildly Heat Treated Meat Systems, B. Egelansdal, S. Kidman, A.-M. Hermansson

Food Structure

Immunohistology was performed with six commercially available antibodies directed against myosins, actins and collagens. The corresponding antigens, appearing on the surface of cryo-sections from meat and meat products heat treated to different end temperatures, were visualized using these antibodies. The meat and meat products were heated from 20 °C to 80 °C. At 80 °C the meat systems were devoid of thermal transitions as judged from differential scanning calorimetric measurements. Our results showed that although reduced binding was the case for systems heated above 60 °C, the signals from the antibody labelling was still sufficiently strong to provide information about …

Two Dimensional, Spatial Arrangement Of Fibronectin Adsorbed To Biomaterials With Different Wettabilities, H. J. Busscher, I. Stokroos, J. M. Schakenraad

Cells and Materials

The effects of concentration, pH and substratum wettability on the two dimensional, spatial arrangement of adsorbed fibronectin are determined. Substrata with different wettability were exposed to a well defined flow of a fibronectin solution (0.1 or 1 mg/ml) in potassium phosphate buffer (pH 7.0 or 4.8) during 120 minutes at a shear rate of 20 s^1. Rotary shadowed replicas of the surfaces were examined by transmission electron microscopy. Well defined structures, island-like in character on the low wettability substrata and knotted, reticulated on the high wettability substrata, could be seen in case of adsorption from pH 7.0 and the …