Life Sciences Commons^™

Chromatid Behavior In Late Mitosis: A Scanning Electron Microscopy Analysis Of Mammalian Cell Lines With Various Chromosome Numbers, D. A. Welter, D. A. Black, L. D. Hodge

Scanning Electron Microscopy

Chromatid activity during the process of nuclear reformation following metaphase is a period of mitosis where little precise information is available. Nuclear reformation requires that chromosomes, at metaphase and chromatids during anaphase and telophase align, position and associate in a clearly defined sequence to insure the specific design of each nucleus. Four cell lines with chromosome numbers ranging from seven to almost seventy were chosen to determine whether the process of nuclear assembly is the same throughout. Chromosomal alignment at metaphase is found to be radial in all four cell lines. Chromosome positioning is essentially the same in all four, …

Dissection Technique For Cochleas Prepared For Scanning Electron Microscopy, Sven Rydmarker, D. E. Dunn, P. Nilsson, C. Lindqvist

Scanning Electron Microscopy

Scanning electron microscopy (SEM) permits a three-dimensional study of the surface morphology of the organ of Corti that is very useful in evaluating the condition of the apical end of the hair cells and the stereocilia. However, some laboratories have experienced problems with curling of the basilar membrane during critical point drying of cochlear specimens prepared For SEM evaluation using the Murakami or osmium thiocarbohydrazide-procedures. This curling of the basilar membrane can obstruct the view of the reticular lamina and the ciliary ends of the hair cells.

We have used a dissection method, referred to as the anchor technique, to …

The Microvascular Architecture Of The Vestibule And The Endolymphatic Duct And Sac Of The Rat In Vascular Corrosion Casts, Takuya Ohmichi, Ryuske Saito, Kiyoshi Matsubara, Kazutaka Terazawa, Shuji Tasaka, Yoshio Ogura

Scanning Electron Microscopy

The blood vessels of the vestibule and the endolymphatic duct and sac (ES) of the rat were reproduced with methacrylate casting medium and observed under a scanning electron microscope.

Dense capillary networks of the macula utriculi and the macula sacculi were observed. The collecting venules from the vestibule emptied into the vein of the vestibular aqueduct (VVAQ). The plexus of the vessels in the ES was triangular in shape and had anastomoses with vessels of the bone and dura and drained into the VVAQ. The posterior meningeal artery (PMA) gave off two branches to the ES. These findings supported the …

Scanning Electron Microscopic Study Of The Surface Of Feline Gastric Epithelium: A Simple Method Of Removing The Coating Material, M. Al-Tikriti, R. W. Henry, F. K. Al-Bagdadi, J. Hoskins, C. Titkemeyer

Scanning Electron Microscopy

Scanning electron microscopic examination of the gastric surface epithelial cells is often hindered by the presence of a coating material. Several methods for removal of coating material on feline gastric mucosa were utilized. The cleansed tissues were evaluated using the scanning electron microscope to assess damage caused by the use of various cleansing methods to surface epithelial cells. The stretched stomach washed several times, including rubbing the mucosal surface with gloved fingers, yielded the best results with no apparent damage to the surface epithelial cells. Flushing unstretched stomachs with saline only did not adequately remove coating material. Flushing unstretched stomachs …

The Three-Dimensional Microstructure Of The Liver A Review By Scanning Electron Microscopy, G. Macchiarelli, P. M. Motta

Scanning Electron Microscopy

The improvement in scanning electron microscopy (SEM) techniques has permitted us to describe the microstructure of the liver. By SEM, the liver peritoneal surface is composed of flat mesothelial cells possessing microvilli and cilia. Hepatic sinusoids connect the portal vessels with the terminal branches of the hepatic vein (central veins). Endothelial cells of the portal space arteries are elongated and arranged longitudinally, while those of the central and portal veins are polygonal and flattened, possessing microvilli. The sinusoidal endothelial cells show both small fenestrations (sieve plates), up to 200 nm in diameter, and large ones, up to 1 𝝁m. Within …

Scanning Electron Microscopy Of The Microvascular System In The Inner Ear, Yoshiaki Nakai, Haruhiko Masutani, Hiromasa Cho

Scanning Electron Microscopy

In the present work, vessels casts in the inner ear of the rat and guinea pig, prepared by casting method using Mercox resin, were subjected to scanning electron microscopic examination and following results were obtained: 1) In adult guinea pig, numerous capillary nets were found in the following parts: stria vascularis, spiral ligament, spiral prominence, Corti's organ, spiral ganglion, plexus cochlearis, semicircular ampulla, saccule, utricle, and endolymphatic sac. These were consistent with functionally and morophologically important areas in the inner ear. 2) In the central side of the area with capillary nets, arterioles were found to run throughout, like a …

Elemental And Ultrastructural Characteristics Of The Egg Capsules Of Nautilus Pompilius, R. J. Koestler, E. D. Santoro, G. Dingerkus

Scanning Electron Microscopy

Six pearly nautili (Nautilus pompilius) raised in captivity produced nonviable egg capsules which were examined using scanning electron microscopy ( SE M) and energy dispersive x-ray spectrometry (EDS). Macro and microscopic observations revealed two distinct and separate walls encircling the yolk sac. Both walls exhibited a porous appearance in cross-section. Protein analysis demonstrated the proteinaceous nature of nidimental gland secretions and egg capsule walls.

EDS analysis of each wall shows the elemental composition to be identical in both, with each wall containing similar proportions of S, CI, Mg, Na, K, and trace amounts of Ca. X-ray mapping of Na and …

Comparison Of Preparative Techniques For Scanning Electron Microscopy Examination Of Soybean Seed Coats In Sectional View, Daniel M. Baker, Harry C, Minor, Merton F. Brown

Scanning Electron Microscopy

Various scanning electron microscopy preparative techniques have been used by researchers to examine sectional views of dry, mature soybean (Glycine~ CL.) Merr.) seed coats. Such previously employed techniques were utilized In our preliminary investigations of seed coat structure, but often yielded unacceptable preservation. Consequently, eight preparative techniques were evaluated In an effort to define conditions required to obtain consistently high quality preservation of soybean seed coats In sectional view. Of the eight procedures tested with the cultivar Williams 82, razor sections and mechanical fractures of dry seed coats yielded the poorest definition of anatomical features. Samples soaked In water prior …

Morphological Observations Of Mineralizing Pericardium Cardiac Grafts, P. Frasca, J. W. Buchanan, R. Z. Soriano, J. M. Dunn, L. Marmon, J. Melbin, S. J. Buchanan, E. E. Golub, I. M. Shapiro

Scanning Electron Microscopy

Pericardial patch grafts were implanted in the hearts of young sheep for periods ranging from two to 120 days. Explants seven to 21 days old revealed the formation of a "pseudoneointima" (PNI) on the blood contacting surface of the pericardium. The PNI was more heavily mineralized than the pericardium. Mineralization was most intense on the blood contacting surface of the PNI and on the chamber surface of the pericardium. After three weeks of implantation, the PNI was much thinner and was organized into a thin fibrous capsule without any signs of mineralization. In the pericardium, mineral deposits were seen in …

Correlation Between Fracture Mechanics Parameters And Fracture Characteristics In Austenites, A. Seibold, R. Löhberg

Scanning Electron Microscopy

Fracture surfaces of austenitic samples tested at room temperature show a correlation between fracture characteristics, Δ K-value and R-ratio: 1) at low Δ K-values up to 400 N/mm³/² and stress ratios of R = 0.1 and R = 0.7, no fatigue striations but fan-like features and flat facets can be seen; 2) fatigue striations, but no facets exist at Δ K-values greater than 900 N/mm³/² and R = 0.1; 3) at a higher stress ratio of R = 0.7 the facets disappear already at lower Δ K-values of about 650 N/mm³/^{2 …}

The Endothelium Of Initial Lymphatics During Postnatal Development Of The Rat Tongue, A. Castenholz

Scanning Electron Microscopy

The luminal surface of the subepithelial lymphatic plexus in the tongue of rats was investigated with SEM at different stages of postnatal development. In newborn and infant animals prominent and branched endothelial cells exhibit a conspicuous phenomenon producing a very irregular inner profile of the vascular wall. Among these cells the spindle-shaped type proves to be an essential component of the valve structures already found in few-day-old animals. There are also prominent cells with a polygonal appearance resembling histioblasts which form with their manifold processes, that partly extend into the lumen, an interlacing cellular pattern. The special morphological characteristics of …

X-Ray Microanalysis Of Urinary Stones, A Comparison With Other Methods, K. M. Kim, H. B. Alpaugh, F. B. Johnson

Scanning Electron Microscopy

A previous study of urinary stones by a combined electron microscopy demonstrated the potential of scanning electron microscopy and X- ray analysis as an analytic tool for urinary stones. Electron diffraction was chosen for the final confirmation of crystals in the study. Although electron diffraction is highly accurate for this purpose, it is desirable to establish the sensitivity of X-ray analysis for the identification of stone components relative to the more commonly used methods. Eighty six consecutive urinary stones were analyzed by X-ray analysis and the findings were compared with those of X-ray diffraction, infrared spectrometry and chemical analysis. The …

Collagen Deposition During Wound Repair, Charles J. Doillon, Michael G. Dunn, Richard A. Berg, Frederick H. Silver

Scanning Electron Microscopy

Collagen fiber diameters, amount of birefringent collagen (brightness) and birefringence retardation were measured in implanted collagen-based sponges containing hyaluronic acid (HA) and fibronectin (FN). In the presence of HA and FN, increased number of fibroblasts and brightness were observed 6 days after wounding. Increased brightness in the presence of HA and FN reflected increased deposition of oriented collagen fibers. From days 9 to 12, increased fiber diameters were similar in implanted collagen-based sponges with or without HA and FN. Increased birefringence retardation in sponges containing HA and FN was consistent with increased packing density of collagen fibers observed by scanning …

Scanning Electron Microscopy As An Analytical Tool For The Study Of Calcified Intrauterine Contraceptive Devices, S. R. Khan, E. J. Wilkinson

Scanning Electron Microscopy

Within the endometrial cavity intrauterine contraceptive devices (IUDs) become encrusted with cellular, acellular, and fibrillar substances. Scanning electron microscopy was used to study the crust. Cellular material consisted mainly of blood cells and various types of bacteria. The fibrillar material appeared to be fibrin which was omnipresent in the crust and formed a thin layer immediately over the IUD surface. X-ray microanalysis of the acellular component of the crust revealed the presence of calcium. No other major peaks were identified. Near the IUD surface characteristic calcium phosphate crystals were present. Their microanalysis showed peaks for calcium and phosphorus. X-ray diffraction …

Towards The Ultimate Scanning Electron Microscope, Albert V. Crewe

Scanning Electron Microscopy

An analysis of all the factors which contribute to the electron probe size in a scanning electron microscope and of the correct method of combining those effects to give optimum performance. Assuming perfect specimen preparation the only other factors are the non-local nature of the basic electron interactions and the nature of the display system.

A Scanning Electron Microscopic Technique For Three-Dimensional Visualization Of The Spatial Arrangement Of Metaphase, Anaphase And Telophase Chromatids, David A. Welter, Lon D. Hodge

Scanning Electron Microscopy

Chromosome and chromatid alignment in mitotic configurations remains a topic of interest because there is little precise information. For example, reconstruction of mitotic configurations from serial sections collected with transmission electron microscopy has proven to be neither practical nor a sensitive method for conceptualizing these arrangements. Similarly light microscopy has been even more unsatisfactory because of its limited resolution and lack of three-dimensional capabilities. These limitations conceivably could be overcome by visualization of mitotic configurations by scanning electron microscopy (SEM). However, SEM has its limitations, of which the most obvious with regard to visualization of mitotic configurations, is that such …

Scanning Electron Microscope Cytochemistry Of Blood Cells, D. Soligo, E. De Harven, E. Pozzoli, M. T. Nava, N. Polli, G. Lambertenghi-Deliliers

Scanning Electron Microscopy

The backscattered electron imaging (BEI) mode of scanning electron microscopy (SEM) has been applied to study various histo-cytochemical reactions in biological specimens since the early seventies. Due to numerous, recent technical improvements the BEI mode of SEM now belongs to the routine of many SEM laboratories.

For cytochemistry, BEI has been mainly used to: visualize intracellular structures and organelles; recognize the different cell types in heterogeneous populations or tissues; study the correlations between enzymatic activities and cell surface features.

We have evaluated the most relevant results obtained in the study of blood cells and the possible future applications of these …

Structural Changes In Mouse Small Intestinal Villi Following Lower Body Hyperthermia, H. M. H. Kamel, K. E. Carr, S. P. Hume, J. C. L. Marigold

Scanning Electron Microscopy

Heating an exteriorised loop of mouse small intestine resulted in marked changes in the shape of the villi as reported earlier. However, the exteriorisation techniques resulted in non-uniformity in both temperature and effect around circumference of intestine and, in addition, the extent to which handling contributed to the observed damage was not known. The work has therefore been extended using lower-body heating in the temperature range 37.5° - 43.0°C.

Heating in the temperature range 37.5° to 41.0°C produced minimal to moderate structural changes, manifested as scattered, vertically collapsed villi amongst predominantly "normal" villi. No villi showed conical or rudimentary forms …

Microstructural Matrix-Crystal Interactions In Calcium Oxalate Monohydrate Kidney Stones, J. Stacholy, E. P. Goldberg

Scanning Electron Microscopy

The role of the proteinaceous matrix in the formation of calcium oxalate kidney stones is still not well understood. Simple scanning electron microscopy (SEM) has been of somewhat limited value in visualizing the organic and inorganic microstructure due to difficulties in obtaining detailed structural information for cut or fractured surfaces.

To help clarify matrix-crystal microstructure, serial sections from 10-20 mm calcium oxalate calculi were partially demineralized with ethylenediamine tetraacetic acid (EDTA) and examined by SEM. Sections etched by EDTA showed a radial crystal structure composed of "microcrystal" subunits. Sections simultaneously EDTA etched and fixed with glutaraldehyde to insolubilize all matrix …

Human Metaphase Chromosome Preparation For Scanning Electron Microscopy - A Consideration Of Inherent Problems, T. D. Allen, E. M. Jack, C. J. Harrison, D. Claugher, R. Harris

Scanning Electron Microscopy

Although the physical dimensions of chromosomes are such that they fall well within the spatial resolving power of scanning electron microscopes, results in the past have been disappointing. This is most likely due to limitations in preparative techniques, coupled with the initial necessity to separate the chromosomes from the remainder of the metaphase cell. Two approaches have been employed, a; to use a variety of isolation buffers which provide bulk chromosome preparations, b; to use metaphase spreads prepared essentially as for light microscopy and re-processed for SEM. In the former, wide variations in chromosome surface topography and fibre organisation arise …

Observation Of Colloidal Gold Labelled Platelet Surface Receptors And The Underlying Cytoskeleton Using High Voltage Electron Microscopy And Scanning Electron Microscopy, R. M. Albrecht, J. A. Oliver, J. C. Loftus

Scanning Electron Microscopy

Fibrinogen conjugated to colloidal gold or colloidal gold-monoclonal anti-glycoprotein IIb/IIIa (fibrinogen receptor) was used to label the receptor on platelets. Whole mount preparations were examined by stereo pair high voltage electron microscopy and then by scanning electron microscopy to determine the feasibility of this approach in detecting the number of receptors and their location relative to the cytoskeletal and surface structure. Both the ligand-gold and antibody-gold labels were effective. The relative numbers of receptors could be seen and their relationship to cytoskeletal structure could be determined. Marked differences in receptor number and distribution were observed when platelets in different stages …

Immuno-Cytochemistry With Backscattered Electrons, D. Soligo, E. De Harven, M. T. Nava, G. Lambertenghi-Deliliers

Scanning Electron Microscopy

Some cytochemical reaction products are visible inside the cytoplasm of cells observed with the scanning electron microscope (SEM) using the backscattered electron imaging (BEI) mode. Methods can be utilized whenever they result in the deposition of heavy metal, like silver, lead or osmium at the sites of the enzymatic reaction.

More recently the BEI mode of the SEM has been demonstrated to improve the detection of immunogold labeled cell surface antigens. Colloidal gold particles, 40 to 15 nm in diameter can be efficiently used for immuno-specific labeling. Moreover, cytochemical reactions can be applied to previously immunogold labeled cells, therefore combining …

High Accuracy And Automatic Measurement Of The Pattern Linewidth On Very Large Scale Integrated Circuits, H. Yamaji, M. Miyoshi, M. Kano, K. Okumura

Scanning Electron Microscopy

High accuracy measurement of pattern linewidth is particularly important in Very Large Scale Integrated Circuits (VLSI) manufacturing.

The measurement of pattern linewidth has been done by optical methods. However, the optical methods have several problems: as the measured value depends on slope angle at pattern edge, thickness and optical property of film and also substrate, there exists a large difference in size (0.3 μm) between the defined edge and the true edge in case of photoresist linewidth measurements. Especially, the optical methods have severe problems to measure bottom of pattern edge and are unsuitable to measure pattern linewidth in VLSI's …

Detection System For Scanning Electron Microscope, J. Hejna, Z. Radzimski, A. Buczkowski

Scanning Electron Microscopy

The kind of information and the quality of the backscattered electron (BSE) images depend upon numerous features of the detector. Therefore, various types of detectors should be used simultaneously to obtain as much of information as possible. The detection system presented here contains a large area semiconductor detector and a BSE to secondary electrons (SE) converter system. These two different kinds of detectors give different BSE images. After subtracting the signal of a semiconductor detector from that of a converter system, an image with good topography and reduced material contrast can be achieved.

The Ependyma Of The Cat Central Canal, With Particular Reference To Its Mitochondria-Containing Bulbs, K. Rascher, K. H. Booz, A. C. Nacimiento, E. Donauer

Scanning Electron Microscopy

The ultrastructure of the ependyma in the central canal of adult cats was examined in both the scanning and the transmission electron microscopes (SEM and TEM).

The same morphological details were seen in the ependyma of the central canal as have so frequently been described in the ependyma of the brain ventricular system, for example bundles of cilia, single cilia, microvilli and occasional small cytoplasmic protrusions. The supraependymal cells and supraependymal nerve fibers found in the central canal also resembled those seen in the ventricular system.

The most striking feature of the canal ependyma were the large, spherical bodies containing …

Scanning And Transmission Electron Microscopic Studies On The Oviducts Of Pekin Ducks Fed Methyl Mercury Containing Diets, A. Balachandran, M. K. Bhatnagar, H. D. Geissinger

Scanning Electron Microscopy

This study was undertaken to examine the effects of varying levels of methyl mercury (MeHg) on the ultrastructure of the surface epithelium of the oviduct of ducks. Accordingly, Pekin ducks were maintained on feed containing varying doses of (0.0; 0.5; 5.0; 15.0 ppm) of MeHg (Group I - control to IV) for 12 weeks and sacrificed. Tissue from the magnum and the shell gland regions of the oviduct was processed for scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that the primary and secondary folds of these regions of the oviducts of the control and 0.5 …

Energy Dispersive X-Ray Analysis Of Ocean Ferromanganese Crusts Using Conventional Zaf Corrections, R. F. Commeau, J. A. Commeau, F. W. Brown, F. T. Manheim

Scanning Electron Microscopy

Ocean ferromanganese crusts are composed of interlayered phases of manganese oxide, iron oxide and oxyhydroxide, calcium carbonate/phosphate, silica, and alumino-silicates. These interlayers are so thin and fine-grained that each phase could not be isolated under the beam of a scanning electron microscope for quantitative x-ray microanalysis. A test was conducted to determine if the grain size of the phases was small enough to allow conventional ZAF techniques to be used without serious errors in the results. A "synthetic" ferromanganese crust was prepared by pelletization of a 1:1 mix of two fine-grained (<5 >micrometer) components. The mean of the energy dispersive …

A Comparison Of Lanthanum Hexaboride, Cold Field Emission And Thermal Field Emission Electron Guns For Low Voltage Scanning Electron Microscopy, J. Orloff

Scanning Electron Microscopy

A comparison of lanthanum hexaboride, cold W(310) field emission and Zr/W thermal field emission cathodes was made by calculating the current-spot size relationship for each, using comparable lenses, to determine which would be suitable for high current operation at 1 keV beam energy, with a focused beam diameter < 0.05 μm. On the criteria of highest current, reasonable operating conditions for the gun for low noise operation and long term cathode stability it was found that the lanthanum hexaboride and cold field emission cathodes are inadequate or marginal and that the best performance is obtainable from the thermal field emission cathode.