Biology Commons^™

Location And Identification Of Colloidal Gold Particles On The Cell Surface With A Scanning Electron Microscope And Energy Dispersive Analyzer, Sinikka Eskelinen, Raija Peura

Scanning Microscopy

The use of colloidal gold particles for locating cell surface components by scanning electron microscopy (SEM) has been restricted due to difficulties in the identification of these gold particles under SEM. It is shown here how the gold particles bound to cell surfaces can be located and identified under SEM using the secondary electron imaging (SEI) mode with an energy dispersive X-ray microanalyzer (EDS). This enables reliable identification of gold particles and good quality micrographs of the cells to be achieved at the same time. The distribution of receptors for two lectins, concanaval in A (ConA) and wheat germ agglutinin …

Polarized Epithelial Cysts In Vitro: A Review Of Cell And Explant Culture Systems That Exhibit Epithelial Cyst Formation, J. A. Mcateer, G. S. Dougherty, K. D. Gardner Jr., A. P. Evan

Scanning Microscopy

The purpose of this paper is to review in vitro cell and explant culture systems that exhibit epithelial cyst formation and that are used as models of polarized epithelial function. We examine a number of culture systems derived from a variety of cell and organ types, briefly describe the methodology and conditions used to establish these cultures and discuss aspects of the experimental application of each system. We conclude that the characteristics of epithelial cyst-forming cultures are dependent upon the origin and identity of the cell population, as well as the multiple factors that define the culture environment. Culture systems …

The Role Of Scanning Electron Microscopy In Ophthalmic Science, P. Versura, M. C. Maltarello

Scanning Microscopy

The eyeglobe is one of the classical domains of Scanning Electron Microscopy (SEM) in biology as it exposes several inner and outer surfaces. Both corneal and conjunctival epithelia towards the tear film as well as the corneal endothelial cells facing the anterior chamber may be accurately evaluated. The architecture of the angle and particularly the morphology of the Schlemm's canal inner wall are clarified by SEM more than by TEM serial reconstruction. The surfaces of the iris and ciliary body, the zonula and the choroidal vessel arrangement are described in great detail. Three distinct types of membrane anchoring devices are …

Extracellular Matrix Production By Osteoblasts On Bioactive Substrata In Vitro, J. E. Davies, T. Matsuda

Scanning Microscopy

Some bone-substitute biomaterials have been classified as bioactive since they allow direct biological bonding to their surface in vivo. Using in vitro techniques, we have re-created the first stages of this biological bonding phenomenon and compared the initial, fibrillar, extracellular matrices produced by migrated primary osteoblast cell populations in contact with both dense and macroporous calcium phosphate substrata, apatite/bioactive glass composite (ABC) and 45S5 bioactive glass (BAG). The first formed fibrils in contact with these materials may be identified as collagen from their morphology as observed by scanning electron microscopy (SEM). However, the organization of this fibrillar material is …

Preparation Of Cytoskeletons Of Cells In Culture For High Resolution Scanning And Scanning Transmission Electron Microscopy, Paul B. Bell Jr., Margaretha Lindroth, Bengt-Arne Fredriksson

Scanning Microscopy

In this tutorial we describe our methods for preparing detergent-extracted cytoskeletons for observation by high resolution scanning (SEM) and scanning transmission (STEM) electron microscopy. We both discuss the theoretical background and provide practical procedures for each of the following steps: cell culture on Formvar-coated gold grids; prefixation with aldehydes or protein crosslinking reagents (homobifunctional N-hydroxy-succinimide esters); extraction with Triton X-100 or Brij 58 detergent in microtubule stabilizing buffer; postfixation in formaldehyde and glutaraldehyde; dehydration; critical point and freeze drying; sputter coating with 1-2 nm of platinum or tungsten; and examination by SEM and both normal and inverted contrast STEM. These …

Preparation Of Cultured And Isolated Cells For X-Ray Microanalysis, K. Zierold, D. Schäfer

Scanning Microscopy

Various electron microscopical preparation techniques are compared with regard to the preservation of the intracellular element distribution as determined by X-ray microanalysis in scanning and scanning transmission electron microscopy. By use of chemical agents for fixation and dehydration ions are redistributed and washed out. This is also true for freeze-substitution. Whole cells are prepared by cryofixation followed by freeze-drying. Interference of intracellular measurements by extracellular elements can be avoided by appropriate washing the cells before cryofixation. The washing medium has to be carefully selected in order to avoid distortions of the original intracellular element content. These problems are circumvented by …

Scanning Electron Microscope And Intragingival Microorganisms In Periodontal Diseases, F. R. Saglie

Scanning Microscopy

During the past two decades there has been an increased understanding of bacterial invasion as a pathogenic mechanism of periodontal diseases. Scanning Electron Microscope (SEM) has played a key role in supporting the idea that bacterial invasion may be another pathogenic mechanism in periodontal disease. This has been due to the fact that SEM has a larger depth of focus and better resolving power than the Light Microscope (LM) and also allows for observation of rather large areas of tissue showing in depth the surface of the sample.

This review deals with information obtained by using SEM as the fundamental …

Evidence Of Variable Zn/Fe In Zinc-Ferrites Produced From Roasting Of Zinc Sulphide Concentrate, R. Lastra, N. Rowlands, J. A. Finch

Scanning Microscopy

Zn-Fe-O phases formed during roasting of concentrates from zinc sulfide ores produce soluble zinc oxide, oxy-sulfates and insoluble ferrite compounds. The ferrites have a general formula ZnOFe₂O₃. However, these ferrites have a range of magnetic properties, suggesting variable stoichiometry. Scanning electron microscopy has been used to obtain the general relationship between the Zn/Fe ratio of the ferrites and their magnetic susceptibility.

Enamel Of Yalkaparidon Coheni: Representative Of A Distinctive Order Of Tertiary Zalambdodont Marsupials, K. S. Lester, M. Archer, C. F. Gilkeson, T. Rich

Scanning Microscopy

The enamel of an incisor and a premolar of Yalkaparidon coheni was examined by scanning electron microscopy in fractured and in sectioned, polished surfaces. The enamel of both teeth demonstrated: complete, ovoid and horse-shoe shaped prisms in a Pattern 2 arrangement; a simple parallel prism course; and, enamel tubules in abundance in the premolar but restricted to the innermost enamel in the incisor. Overall, the enamel ultrastructure supports the marsupial affiliation proposed for Yalkaparidon coheni but does not unambiguously ally it with any other order of marsupials.

The observation of a significant ultrastructural difference between the anterior and posterior teeth …

Intracellular Water Distribution And Aging As Examined By X-Ray Microanalysis, Thomas Von Zglinicki

Scanning Microscopy

The results reviewed here demonstrate that 1. the distribution of dry mass as observed in frozen-dried cryosections might be used as an unbiased measure of intracellular dry mass resp. water distributions in the tissue in vivo and 2. the well-known loss of water from cells during aging is solely due to a water loss from mitochondria without changes in the water content of all other components of the cell in the case of rat liver and heart muscle.

The reason for the water loss might be increased counter ion binding by membrane-bound enzymes due to decreased fluidity of the inner …

Surface And Sub-Surface Composition And Properties Of Ion-Bombarded Lithium Alloys, A. R. Krauss, D. M. Gruen, N. Q. Lam, A. B. Dewald, M. G. Valentine, A. Sagara, K. Kamada

Scanning Microscopy

Lithium-bearing alloys such as Si-Li, Al-Li and Cu-Li are of importance in a variety of technological applications, many of them depending on the fact that the surface composition of these alloys differs significantly from that of the bulk, both at thermal equilibrium and under ion bombardment. During ion sputtering, these materials exhibit a variety of phenomena which affect the surface composition and concentration depth profile in a complex manner. We present here experimental measurements of the surface and near-surface composition profiles of sputtered Cu-Li and Al-Li alloys. The experimental results are interpreted in terms of surface loss and radiation-induced segregation …

Multiphoton Ionization Followed By Time-Of-Flight Mass Spectroscopy Of Sputtered Neutrals, M. J. Pellin, C. E. Young, D. M. Gruen

Scanning Microscopy

Multiphoton ionization (MPI) by pulsed, tunable lasers provides a sensitive means for detection of neutral atoms, resulting from the high probability achievable in both the ionization and subsequent detection steps. Substantial selectivity is achieved by excitation between energy levels of the atom of interest. This resonant MPI technique can access all atomic states including ground and metastable levels.

The high efficiency of MPI technique permits detailed sputtering data to be obtained with minimal target damage. The goal is to obtain velocity and angular distributions for each energy level of every sputtered species. In practice, two types of experimental configurations have …

A New Method For Finishing Minicavities, A. Lussi, M Gygax, P. Hotz, D. Lüthi

Scanning Microscopy

Minicavities were prepared in 26 caries-free teeth. Cavity preparation and the finishing of the occlusal area and the gingival floor was done with diamond burs (diameter 1 mm, grain sizes 90 μm and 15 μm, respectively). For the finishing of the axial box margin and the proximo-cervicaI curved border, a new set was developed: It is composed of an EVA-system with the total amplitude reduced to 0.34 mm, and a highly flexible file (Cavishape, grain 15 μm). The shape of this file had to be modified in order to follow the proximo-cervical curvature. The efficiency of the new device was …

Proton Microprobe And Particle Induced X-Ray Emission (Pixe) Analysis For Studies Of Pathological Brain Tissue, K. G. Malmqvist, A. Brun, K. Inamura, E. Martins, L. G. Salford, B. K. Siesjö, U. A. S. Tapper, K. Themner

Scanning Microscopy

Particle Indiced X-ray Emission and proton microprobe analyses have been applied for the investigation of regional elemental distributions in connection with various pathological states in the brain. Malignant brain tumours and adjacent histologically intact tissue removed during surgery were analysed with PIXE. Systematic elemental variations, e.g., for calcium and selenium, were observed in the tumour front. The proton microprobe was applied to study the Ca and K concentrations in various cell strata in hippocampus following transient ischaemia in rat brain. Significant increases in the Ca level occurred in selectively vulnerable cells within 48 h after the ischaemia.

The Growth Of Calcium And Strontium Sulfates On Barium Sulfate Surfaces, L. Perez, G. H. Nancollas

Scanning Microscopy

The crystallization of calcium sulfate dihydrate (gypsum) and strontium sulfate (celestite) induced by the presence of barium sulfate (barite) surfaces has been studied using a Constant Composition kinetic method. In contrast to calcium sulfate, strontium sulfate appears to grow epitaxially on barium sulfate surfaces. However, barium sulfate induces calcium sulfate dihydrate precipitation from meta stable supersaturated solutions of the salt. Following nucleation, the rate of growth of strontium sulfate was found to be a second order with respect to supersaturation indicating a surface dislocation growth mechanism. The observed epitaxial growth is in agreement with calculations based on crystal lattice mismatch.

Zinc Deficiency: Specific Scalp Hair Defects Seen By Scanning Electron Microscopy May Provide A Valuable New Test, D. W. Gregory, L. Stankler

Scanning Microscopy

Zinc deficiency in man results in multisystem disease. It may be acquired or hereditary; the latter can be fatal if left untreated. Premature babies are particularly susceptible to zinc deficiency. Unfortunately no simple, reliable test for zinc status exists at present.

Short, newly-emerging scalp hair samples from 3 classical cases of zinc deficiency all showed the same characteristic abnormalities when examined by scanning electron microscopy, i.e. straight, blunt tips bearing scales, unusually thick cuticular scales with jagged free-edges, and very fine longitudinal corrugations in individual scales. These abnormal features occurring together appear to be specific for zinc deficiency; they also …

Scanning Electron Microscopy Of The Spermatheca Of Plethodon Larselli (Amphibia: Plethodontidae): Changes In The Surface Morphology Of The Spermathecal Tubule Prior To Ovulation, Christine M. Davitt, John H. Larsen Jr.

Scanning Microscopy

Spermathecae from eight mature female Larch Mountain salamanders (Plethodon larselli) were used to study cellular changes accompanying the administration of ovulation-inducing pregnant mare serum gonadotropin (PMSG). Animals injected daily with 25 IU of PMSG were sacrificed on day 2 or day 4. Ultrastructural alterations of the spermathecal tubules include an increase in the synthesis and release of product into the lumen and hypertrophy of two epithelial cell types by day 4. One cell type exhibits apocrine blebs and is covered with microvilli; the other contains large spherical vesicles and has only a few, short microvilli on its surface. These changes …

Developmental And Radiobiologic Characteristics Of Canine Multinucleated, Osteoclast-Like Cells Generated In Vitro From Canine Bone Marrow, T. M. Seed, L. V. Kaspar, F. Domann, G. K. Niiro, D. A. Lebuis

Scanning Microscopy

We report here our initial observations on the growth and morphology, and developmental radiosensitivity of giant, multinucleated, osteoclast-like cells (MN-OS} generated through in vitro cultivation of hematopoietic progenitor-enriched canine bone marrow samples. Maximum cell densities of 5.5 x 10³ to 6.5 x 10³ MN-OS per cm² of growth area were achieved following 10 to 14 days of culture at 37°C. Acute gamma irradiation of the initial marrow inocula resulted in significant, dose-dependent perturbations of MN-OS formation, growth, and development. Attempts to estimate radiosensitivity of MN-OS progenitors from canine marrow yielded a range of D_O values from …

Sem Of Canine Chromosomes: Normal Structure And The Effects Of Whole-Body Irradiation, G. K. Niiro, T. M. Seed

Scanning Microscopy

Canine chromosomes are not only numerous (38 autosomal pairs), but they are small (compared to human chromosomes) and morphologically similar as well. Analysis of the canine karyotype by light microscopy (LM) of banded chromosomes is, thus, difficult, and the literature on the canine karyotype is scanty. In this study, we describe examination of chromosomes from normal and chronically irradiated dogs with the scanning elect ran microscope (SEM). Metaphase chromosomes from bone marrow aspirates were Giemsa-banded with either 0.025% trypsin alone or 0.1% trypsin preceded by 10% H2O2 and prepared for SEM. Examination of chromosomes from normal dogs revealed cylindrical chromosome …

Silver As A Removable Conductive Coating For Scanning Electron Microscopy, A. A. Mills

Scanning Microscopy

A thin film of silver, applied by sputtering or vacuum evaporation, provides an excellent conformal conductive coating for scanning electron microscopy of insulating specimens. When no longer required it is easily removed with Farmer's reducer a dilute aqueous solution of potassium ferricyanide and sodium thiosulphate. No damage was apparent to fine structure in the calcite matrix of ostracode shells, or to other biological tissues. No problems have been encountered with grain in the silver film at magnifications up to 15,000 X, or in the storage of coated specimens in a desiccator for periods exceeding 6 months.

Enamel Structure In Primates: A Review Of Scanning Electron Microscope Studies, L. B. Martin, A. Boyde, F. E. Grine

Scanning Microscopy

Comparative studies of dental enamel microstructure have involved three main areas of enquiry, with structural features having been investigated in relation to developmental mechanisms, function and/or phylogeny. The phylogenetic, or taxonomic aspect has been emphasized in the majority of studies involving the Order Primates, where efforts have focused upon attempts to recognise structural differences among various hierarchical groups.

Studies of primate enamel microstructure by SEM are reviewed here, with emphasis on what has been learned concerning the most suitable preparative techniques that can be employed, and with particular emphasis to the relevance of enamel microstructure in taxonomic analyses of living …

The Capabilities Of The Microprobe Kontron Image Analysis System: Application To Mineral Beneficiation, W. Petruk

Scanning Microscopy

Image analysis is a technique for determining quantities, grain size distributions, grain orientations, intergrowths, associations, liberations and degrees of alteration of minerals or phases in naturally occurring and processed materials. It is performed by analysing images of polished or thin sections of the material under study. To obtain accurate results the images must be faithful reproductions of the material, and each mineral or phase displayed in the images must be distinct enough to be automatically discriminated and identified without operator interaction. An image analysis system that meets these requirements was developed in the Process Mineralogy Section at CANMET by interfacing …

The Effects Of Polepiece Saturation On The Electron Optical Properties Of Asymmetric Condenser - Objective Lenses, Wenxiong Chen

Scanning Microscopy

The electron optical properties of an asymmetric magnetic condenser-objective lens are determined not only by its geometric structure and shape parameters, but also by the degree of saturation of its polepieces. A systematic investigation has been carried out for a series of asymmetric magnetic condenser-objective lenses. Results show that, owing to its small bore, the lower polepiece of such an asymmetric condenser-objective lens has considerable effects on the electron optical properties. When this polepiece is appropriately highly saturated, an asymmetric condenser-objective lens possesses low spherical aberration and chromatic aberration coefficients. On the other hand, the large bore of the upper …

Microscopic Effects Of Predator Digestion On The Surfaces Of Bones And Teeth, John M. Rensberger, Hartmut B. Krentz

Scanning Microscopy

Concentrations of small fossil mammals are frequently encountered in Cenozoic deposits, but the causes for such accumulations have seldom been determined. In many cases the tooth, jaw, and limb fragments appear to be well-preserved under light microscopy, and it is difficult to differentiate damage due to predator digestion from breakage and abrasion due to physical agents. In order to find more specific evidence of predator digestion, we used a scanning electron microscope (SEM) to examine the surface microstructure of bones and teeth consumed by Bubo virginianus (great horned owl) and Canis latrans (coyote), which prey upon similar species. Effects …

Metal Ion And Cluster Beams For Microelectronic Research And Development: A Review, G. Ben Assayag, P. Sudraud

Scanning Microscopy

Applications of focused ion and cluster beams emitted by liquid metal ion sources are particularly attractive in microelectronic engineering. We overview this area of research and development adding recent results concerning repair, tuning and characterization obtained either by focusing ions or droplets on a microcircuit controlled by in-situ SEM observation of the process.

Microcorrosion Casting In Normal And Pathological Biliary Tree Morphology, E. Gaudio, L. Pannarale, F. Carpino, G. Marinozzi

Scanning Microscopy

The organization of the intrahepatic biliary tree was studied in three dimensions by scanning electron microscopic (SEM) corrosion casts, in normal and cholestatic rat liver.

In the normal liver the observation revealed the features of the biliary passages from the bile canaliculi to the canaliculo-ductular junction, to the ductules and the bile ducts, confirming previous SEM observations.

In cholestatic liver, the modifications and the proliferation of bile ductules appear clearly.

Resin flow from canalicular to sinusoidal network was never observed.

The method was found to be very useful in the evaluation of the architecture of the intrahepatic biliary tree, under …

Extraneous Background-Correction Program For Matrix Bound Multiple Point X-Ray Microanalysis, W. C. De Bruijn, M. P. C. Van Miert

Scanning Microscopy

A program is described that allows online determination of extraneous background in multiple point X-ray microanalytical matrices. The program is based upon the calculations of the extraneous background for the film (when present), the standard and the unknown by (100 sec.) point analysis. The program searches for a peak-free part of the spectrum in which the calculated value for the extraneous background is about equal to the value in this region of the spectrum (=b_e). Online the contents of this b_e-region is subtracted from an unmanipulated continuum region in the vicinity of the element present in …

Presence Of Calcium Oxalate Crystals In The Mammalian Thyroid Gland, Raymond L. Hackett, Saeed R. Khan

Scanning Microscopy

Birefringent crystals of calcium oxalate have been previously identified in the colloid of human thyroid glands. We found such crystals in 19/20 adult thyroids at autopsy, in 4/ 20 infants at autopsy, and, using frozen sections, in 19/20 thyroids partially or totally removed at surgery. These crystals were soluble in hydrochloric acid, insoluble in acetic acid, and contained only calcium by energy dispersive X-ray microanalysis, confirming their calcium oxalate character. Similar crystals were found in equine and ovine thyroids.

Tip-Techniques For Microcharacterization Of Materials, Y. Martin, C. C. Williams, H. K. Wickramasinghe

Scanning Microscopy

The invention of the Scanning Tunneling Microscope has stimulated the development of new techniques for microcharacterization of materials, which are based on the use of a very fine tip. Two of these techniques have emerged about one year ago, the Thermal Profiler and the Atomic Force Microscope. Both techniques have recently demonstrated the capability to profile and image conductors and insulators. The resolution attained varies from approximately 50 nm by the Thermal Profiler to a few nanometers with the Atomic Force Microscope, therefore competing with the resolution obtained with electron beam microscopy. We shall describe the principle of these techniques, …

Interferon-Induced Surface Alterations In Hairy Cells. A Review, Haim Gamliel, Dorit Gurfel, Shi-Hua Wu, Harvey M. Golomb

Scanning Microscopy

Hairy cells (HCs), derived from the peripheral blood and spleen of hairy cell leukemia (HCL) patients, constantly displayed both ruffles and microvilli. HCs which were kept in culture for up to three days exhibited extremely polarized and active surfaces with elongated microvilli and exaggerated "spiked" ruffles. Cells derived from 11 cases of HCL were treated with alpha-interferon (IFN) in-vitro and examined by immuno -scanning electron microscopy (immuno-SEM). In 8 cases, up to one-third of the IFN-treated hairy cells displayed deformed surfaces with "bubbling" membrane and markedly villous bud-like formations. Monoclonal antibodies (MoAb), used in conjunction with immuno-qold labeling, facilitated better …