Biology Commons^™

Diluted And Undiluted Mercox Severely Destroy Unfixed Endothelial Cells. A Light And Electron Microscopic Study Using Cultured Endothelial Cells And Tadpole Tail Fin Vessels, J. Gassner, A. Lametschwandtner, T. Weiger, H. C. Bauer

Scanning Microscopy

Mercox is a methylmethacrylate-based resin which is widely used for vascular corrosion casting with subsequent scanning electron microscopic analysis. In the present study the effect of undiluted and diluted Mercox (4+1; volume + volume; Mercox: monomeric methylmethacrylate (MMA); 0.02 g catalyst MA/ml Mercox) and methylmethacrylate with and without catalyst MA (0.625 g/10 ml MMA) on fixed and unfixed endothelial cells was studied. Light microscopy (LM) of cultured capillary endothelial cells (ECs), which were replicated with diluted or undiluted Mercox shows degranulation and membrane perturbation of ECs, while no morphological changes occur in glutaraldehyde-prefixed ECs. Scanning electron microscopy (SEM) of replicas …

Superstructures Of Graphite Intercalation Compound Formed By Sodium-Hydroxide Solution Studied By Scanning Tunneling Microscopy, Koji Miyake, Aiso Yoshiaki, Makoto Komiyama, Hidemi Shigekawa

Scanning Microscopy

Highly oriented pyrolytic graphite (HOPG) treated with sodium hydroxide solution was found to show an X-ray diffraction pattern characteristic of a stage-8 intercalation compound. Superstructures such as 2 X 2, √3 X √3 and noble orthorhombic lattices were observed on the NaOH-treated graphite surfaces by scanning tunneling microscopy, as was previously observed on stage-1 alkali-metal graphite intercalation compound (GIC) surfaces formed by Li, K, Rb and Cs intercalates. The orthorhombic phase has a periodic structure formed by four bright and two dark rows, which were explained by the intercalant arrangement occupying two different sites, in the GIC.

Data Handling In Quantitative Microanalysis In Biology, V. Starý

Scanning Microscopy

In cell biology, electron probe X-ray microanalysis can reveal the distribution of chemical elements inside a single cell. The full description of a biological system (cell population, tissue) requires a great number of spot measurements. In quantitative analysis, the measurements are subject to experimental errors of several types; moreover, the relations between the resulting values are usually more interesting than the absolute concentrations. Nevertheless, the proper evaluation of quantitative values can discover information more on the object of study.

A system of simple statistical tests is suggested here which can solve several problems. Some concentration values can be far from …

Role Of Agglomeration In The Early Stages Of Papillar Stone Formation, O. Söhnel, F. Grases, L. Garcia-Ferragut

Scanning Microscopy

Possible effects of crystal agglomeration on the early stages of calcium oxalate papillar stone formation are evaluated. The collecting ducts are filled with liquid that flows laminarly as established through hydrodynamical and physicochemical considerations. Under such conditions, agglomeration due to laminar shear forces proceeds. Agglomeration of calcium oxalate monohydrate crystals present in urine at a concentration typical for clinically observed crystalluria cannot result in the formation of a particle sufficiently large enough to be retained in the Bellini's duct and become a papillar stone nidus (nucleus). Formation of such an aggregate during the passage time of urine through the duct …

Direct Observation By Scanning Tunneling Microscopy Of The Two-Dimensional Lattice Structure Of The S-Layer Sheath Of The Archaeobacterium Methanospirillum Hungatei Gp1, B. L. Blackford, W. Xu, M. H. Jericho, P. J. Mulhern, M. Firtel, T. J. Beveridge

Scanning Microscopy

Observation of the two-dimensional (2-D) 3 nm x 3 nm lattice structure of the S-layer sheath of the archaeobacterium Methanospirillum hungatei is reported for the first time by scanning tunneling microscopy. The samples consisted of sheath fragments deposited on a TaSe₂ substrate and coated with a Pt/Ir film. In addition to confirming the 2-D structure, the images reveal some new information about the nano-scale details of the sheath structure. A lateral resolution of 1 nm was achieved, suggesting that the grain size of the Pt/Ir films was much less than for similar films deposited on a smooth metal surface.

Etiology Of Experimental Calcium Oxalate Monohydrate Nephrolithiasis In Rats, W. C. De Bruijn, E. R. Boevé, P. R. W. A. Van Run, P. P. M. C. Van Miert, J. C. Romijn, C. F. Verkoelen, L. C. Cao, F. H. Schröder

Scanning Microscopy

In a rat-model system, tubular crystal retention as a possible mechanism for the etiology of nephrolithiasis in man, was studied by conventional transmission electron microscopy. The animals were supplied for nine days with a crystal-inducing diet, with ethylene glycol plus NH₄Cl in their drinking-water. After this induction period, a two day regime with fresh drinking-water was included, to allow crystals to be removed by spontaneous crystalluria. After aldehyde fixation of the rat kidneys, large crystals were seen inside the tubular lumen. The crystals were attached to cell surfaces and covered by neighboring epithelial cells. Some crystals were overgrown …

Electronic Trap Microscopy - A New Mode For Scanning Electron Microscopy (Sem), H. -J. Fitting, Th. Hingst, R. Franz, E. Schreiber

Scanning Microscopy

Insulating layers on conducting substrate are investigated by means of secondary electron field emission SEFE in a digital SEM. The kinetics of charge storage and release with time and temperature are controlled and recorded by an external computer.The evaluation is performed pixel-wise with respect to electronic trap concentration n_t0, trap capture cross section σ_c and thermal activation energy E_t. Mapping of these trap parameters indicates hidden inhomogenities, defects and pre-treatments of the dielectric layers as well as the pattern of thermal bleaching and release of electrons. The latter ones appear as inhomogeneous processes starting with …

Sequencing Of Proteins Extracted From Stones, J. P. Binette, M. B. Binette

Scanning Microscopy

Proteins from urinary tract and gallbladder stones were extracted and characterized to determine the composition of the matrix and possibly unravel the role of the organic phase in stone formation. Proteins from crushed stones were extracted by electrodialysis and concentrated in the Amicon centricon cartridge or by lyophilization after dialysis against distilled water. Aliquots were first analyzed by isoelectric focusing in gel and if suitable subjected to two-dimensional (2D) electrophoresis. The most promising spots were harvested and the N-terminal amino acids sequenced, thus providing maximum information with minimum expenditure of material. The 2D separations and amino acid sequences of several …

Methodological Aspects Of Spontaneous Crystalluria Studies In Calcium Stone Formers, C. A. Bader, A. Chevalier, C. Hennequin, P. Jungers, M. Daudon, O. Beaugendre, M. P. Hoarau

Scanning Microscopy

Despite nearly a half-century of study, the clinical value of spontaneous crystalluria (Cx) examinations in calcium stone formers (CaSF) is still uncertain. The analytical complexity of urine particle study is largely responsible for this situation. As a result, there is no consensus regarding technical methods in Cx with several techniques for urine sampling and three different instruments currently used for particle study, namely, particle counting (PC), light microscopy (LM) and petrographic microscopy (PM). In this work, we first examined urine sampling and instrument methods regarding their appropriateness for Cx studies. Then we performed a comparative analysis of Cx studies in …

Arrangement Of Elastic Fibres In The Integument Of Domesticated Mammals, W. Meyer, K. Neurand, R. Schwarz, T. Bartels, H. Althoff

Scanning Microscopy

The hairy skin of important domesticated mammals (12 species) was studied with scanning electron microscopy, transmission electron microscopy, laser scanning microscopy, and several light microscopical methods, to obtain more information about three-dimensional elastic fibre arrangement. It was obvious that there is a basic construction scheme of the elastic fibre meshwork as present in the upper and mid-dermis, with special regard to the size, number, and grouping of hair follicles. In the densely-haired species, in particular, a typical elastic mat with horizontal fibres is formed. In many of the sparsely-haired animals, the upper and mid-dermis show a sponge-like elastic system. In …

General Pattern And Morphological Specializations Of The Avian Cochlea, Franz Peter Fischer

Scanning Microscopy

In different bird species, there is a common pattern in the hair-cell morphology and innervation of the basilar papilla; the absolute values, however, are species-specific. In the barn-owl papilla, an extreme being case, the basal high-frequency part of the papilla is greatly expanded. In this behaviorally most important frequency range of the barn owl, the number of afferent nerve terminals to neural hair cells is extensively increased. Instead of about 2 afferent terminals as in other species, up to 20 afferents are present. In the bird species studied (chicken, starling, emu, barn owl), the area of the afferent nerve terminals …

Ultrastructural Patterns Of Cell Damage And Death Following Gamma Radiation Exposure Of Murine Erythroleukemia Cells, R. Di Pietro, E. Falcieri, L. Centurione, M. A. Centurione, G. Mazzotti, R. Rana

Scanning Microscopy

Radiation causes damage to cell surface membranes, cytoplasmic organelles, and the nuclear process of DNA synthesis and repair, and this eventually results in different modes of cell death. In this study we examined murine erythroleukemia (MEL) cells, exposed to 15 and 60 Gy of 10 MeV photonic energy, and left in culture for up to 96 hours. Electron microscopical analysis was performed on conventionally embedded samples and freeze-fracture replicas, in order to detect ultrastructural patterns of cell damage and death. Of interest was the observation of chromatin condensates, nuclear membrane associations and nuclear pore redistribution during early apoptosis. Pronounced rearrangements …

Glycol Methacrylate Embedding And Microwave Staining For Light Microscopy Of The Mouse Cochlea, Bharti Katbamna, Atha Ralston

Scanning Microscopy

This study examined the utility of a methacrylate-based embedding medium and microwave staining for light microscopic quantification of hair cells and spiral ganglion cells in the mouse cochlea. The most important phase of the preparation process involved slowing down the polymerization process. The tissue molecules so locked within the plastic matrix produced excellent preservation of the organ of Corti and adjacent structures including the spiral ganglion, as well as tissue ionic charges. Excitable by microwaves, these ionic charges accelerated the movement of the basic dye (hematoxylin) into the tissue, reducing the time for this segment of the staining process from …

Time-Resolved Cryofixation Methods For The Study Of Dynamic Cellular Events By Electron Microscopy: A Review, Keith P. Ryan, Gerd Knoll

Scanning Microscopy

The preservation of cells for electron microscopy by chemical fixation is a lengthy process, requiring up to 30 minutes for cytoplasmic stabilisation. This time lag enables many changes to occur in specimens so that they may not reflect their living state when they are observed in electron microscopes. Many artefacts can be avoided by using cryofixation, which freezes specimens over a period that is measured in milliseconds, so that specimens are preserved by cryoimmobilisation. This time resolution can be used to study rapid processes in biology and chemistry because, although electron microscopes cannot observe dynamic cellular events directly, processes can …

Imaging Of Local Thermal And Electrical Conductivity With Scanning Force Microscopy, M. Maywald, R. J. Pylkki, L. J. Balk

Scanning Microscopy

The evaluation of thermal and electrical properties has been demonstrated using a scanning force microscope under ambient air condition. For the first time, the investigation of thermal conductivity on a chemical vapor deposited (CVD) grown diamond surface has been performed with a lateral resolution below 200 nm. Depending on the growing parameters, structures consisting of lines of different thicknesses and spacings are visible. The determination of the electrical structure has been carried out with a resolution of 2 nm using the contact current mode (CCM) showing similar structures. The thermal images exhibit a high thermal conductivity mostly on the diamond …

Epicuticular Wax Load Of Near-Isogenic Barley Lines Differing In Glaucousness, A. Febrero, J. L. Araus

Scanning Microscopy

Scanning electron microscopy observations of epicuticular waxes on flag leaves (blades and sheaths) and ears were carried out on a pair of near-isogenic lines of two-row barley (Hordeum vulgare L. ), derived from cv. Troubadour, differing in their degree of glaucousness (wax bloom). Plants were grown under irrigated and rainfed mediterranean conditions. Wax bloom in flag leaves consisted mainly of thin wax deposits over the blade, and tubes over the sheath. Wax bloom in the blade was denser and more uniformly arranged on the adaxial than on the abaxial side. In the ears, tubular waxes predominated, forming dense patches …

Microvascular Corrosion Casting Of The Rat Mandibular Joint: A Technical Approach, Etienne Piette, Alois Lametschwandtner

Scanning Microscopy

The rat mandibular joint is a ginglymoarthrodial joint deeply hidden under the zygomatic process of the squamosal bone. This joint was studied by scanning electron microscopy (SEM) of microvascular corrosion casts in 47 adult rats. Six additional rats were injected with India ink and thick sections of the joint area were examined by light microscopy. The small size of the joint (2.5 mm x 1.5 mm in occlusion), the existence of two slit-like joint compartments, the close proximity of bones and soft tissues in a mobile structure, and the intimate relationships of the joint with adjacent skeletal muscles made the …

Detection Of Topographic Contrast In The Scanning Electron Microscope At Low And Medium Resolution By Different Detectors And Detector Systems, J. Hejna

Scanning Microscopy

Origins of topographic contrast in the scanning electron microscope (SEM) are different at different resolution levels. At low resolution, tilt contrast of large features dominates; at medium resolution, diffusion contrast of features smaller than an interaction volume of primary electrons dominates.

The secondary electron (SE) signal, commonly used in the SEM, does not give a good tilt contrast; better contrast can be obtained with backscattered electron (BSE) signal of a converter and a sector-shaped ring detector. For obtaining topographic images from signals containing topographic and material contrast, signals of detector systems containing two or more detectors are mixed. Detector systems …

Electron Microprobe Analysis Of Electrolytes In Whole Cultured Epithelial Cells, S. Borgmann, M. Granitzer, J. Crabbé, F. X. Beck, W. Nagel, A. Dörge

Scanning Microscopy

Microprobe analysis was used to determine electrolyte contents in whole epithelial sheets of A6 cells and to investigate the most critical points of this method. Analysis of dextran standard sections of different thickness revealed that low accelerating voltages of about 10 kV are best suited for whole freeze-dried cells on thick supports, since 5 μm thick sections are not penetrated by 10 kV electrons. Washing of A6 cells for 10 sec with distilled water led to cell swelling of about 40%, but the molar concentration ratios and the concentrations per dry weight (dw) were not altered. Washing for 60 sec …

Ultrastructural Features Of Apoptosis, Elisabetta Falcieri, Pietro Gobbi, Loris Zamai, Marco Vitale

Scanning Microscopy

Apoptosis is a gene-directed physiological and programmed process of cell deletion aimed at the regulation of tissue and organ development. It affects different cell types and is triggered by a variety of stimuli all inducing closely comparable structural changes. Despite the deeply different morphology and metabolism of the cell models and the various inducers and their initial effects, a convergence seems to take place in a common metabolic pathway that, in most cases, involves the activation of a Ca²⁺ dependent endonuclease. A growing body of data is now available on the molecular events that lead to DNA damage. DNA …

Radiation Induced Membrane Changes And Programmed Cell Death: Possible Interrelationships, F. Ojeda, H. A. Diehl, H. Folch

Scanning Microscopy

A short review of the evidence that lymphocyte membranes are a target for the initiation of irradiation induced programmed cell death (PCD) is given. It is assumed that for lymphocytes PCD represents an essential physiological mechanism in order to prevent degeneration of the biological system involved. Initiation of PCD can be obtained by a pharmacological activation as well as with irradiation. In both cases, protein kinase-C (PKC) is involved in the signal transduction from the cellular membrane to the nucleus where, by means of a metabolically active process, DNA fragmentation is induced. It is hypothesized that processes connected to lipid …

Stereometry Of Crystalline Phases Observed In Scanning Electron Microscopy, M. A. Martínez, J. M. Gómez De Salazar, A. J. Criado

Scanning Microscopy

A study of edges and angles of known samples has been performed by means of stereoscopic pairs with electron microscopy in two and three dimensional systems. The derived equations have been included in a computer program. Measurements on stereoscopic pairs with different tilt angles using several crystals of galena, calcite and other objects with known dimensions have been performed. The optimum tilt angles have been obtained by comparison with the actual values, and a logarithmic ratio between these angles and the stereoscopic pairs magnification has been found. The errors obtained using this system of calculation are lower than 6% in …

Scanning Electron Microscopy And Energy-Dispersive X-Ray Microanalysis Studies Of Several Human Calculi Containing Calcium Phosphate Crystals, Tetsuo Kodaka, Kazuhiro Debari, Tsuneyoshi Sano, Masayuki Yamada

Scanning Microscopy

Human calcium phosphate calculi: two sialoliths, a urolith, a rhinolith, and a tonsillolith were investigated by scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX). The sialoliths and urolith had appositional shells with thick cortices, respectively, around several nuclei composed of calcospherulites and a rubber-film fragment. The rhinolith had a thin cortex with appositional laminations around a glomerulus-like mass of calcified cotton-like strings. The tonsillolith had a rough cortex with appositional laminations. Its porous interior was composed of numerous calcified conglomerates with microorganisms and calcified masses with fine appositional laminations around the conglomerates. The major crystals were identified as biological …

An X-Ray Microanalytical Study On The Effects Of Ouabain And N-Ethyl Maleimide On The Elemental Concentrations In Malpighian Tubule Cells Of Locusta, Natalia Pivovarova, John H. Anstee, Ken Bowler

Scanning Microscopy

X-ray microanalysis was used to study elemental distribution in Malpighian tubule cells of Locusta migratoria and how these are affected by the replacement of bathing medium K⁺ with Rb⁺ and by inclusion of the transport inhibitors ouabain and n-ethyl maleimide (NEM) in standard (K⁺-containing) and Rb⁺-Ringer (K⁺-free) solutions. Incubation of tubules in standard Ringer containing 1 mM ouabain dramatically affected the intracellular levels of K and Na. The intracellular K concentration fell and Na concentration increased in all regions studied. Despite this, a gradient of increasing K concentration from basal to apical …

Scanning Electron Microscopic Study Of The Three-Dimensional Structure Of The Collagen Networks Of Gastric Cancer, Masuki Iyoki, Keijiro Araki, Takuro Ogata

Scanning Microscopy

The three-dimensional structure of the collagen networks in human gastric carcinoma was examined by scanning electron microscopy (SEM) after treatment with the cell-maceration method using a low temperature NaOH solution. Based on stromal content, the poorly differentiated adenocarcinoma can be divided into the medullary carcinoma area and the scirrhous carcinoma area. In the medullary carcinoma, the collagen sheath around the small tumor cell acinus formed spherical chambers (20-30 μm in diameter) with fenestrations (about 5 μm in diameter) connecting the chambers. The collagen sheath was composed of fine collagen fibrils (about 50 nm in diameter). In the scirrhous area, there …

Collagen Fiber Arrangement In Temporo-Mandibular Joint (Tmj) Disks From Human Subjects With Functional Diseases. Scanning Electron Microscopy Investigations, C. Piacentini, C. Marchetti, G. Bernasconi, P. Menghini, U. Baciliero, C. Brusotti

Scanning Microscopy

Twelve articular disks from patients with temporo-mandibular joint (TMJ) arthropathy were studied and compared with two normal disks. Scanning electron microscopy (SEM) examination of the surfaces and of longitudinal and cross-sections of the disks allowed the observation of the arrangement of the collagen fiber component in different parts of the disk. The superficial part of the articular disks appears to be formed by rather compact fibers. The internal portion is usually formed by bundles of collagen fibers in sheets, alternating with isolated fibers arranged in a parallel or irregular way.

In some samples, blood vessels were observed. Our investigations suggested …

Different Forms Of Corrosion Casts, Seyedhossein Aharinejad, Peter Böck

Scanning Microscopy

We have previously described artifacts in corrosion casts prepared with Mercox®, diluted with methylmethacrylic acid (MMA). Using scanning electron microscopy (SEM) of casts and light microscopy (LM) of tissue sections, we found new forms of artifacts in casts prepared with both undiluted and MMA-diluted Mercox®. When undiluted Mercox® was used, most of the casts did not show artifacts. Artifacts were rarely seen and comprised empty casts consisting of a rim, while endothelial cell nuclear imprints and other vascular wall structures were replicated. Other casts sometimes showed vessels with a fine granular surface or some with conglomerates in their internal structure, …

Energy-Filtering Transmission Electron Microscopy As A Tool For Structural And Compositional Analysis Of Isolated Ferritin Particles, A. L. D. Beckers, W. C. De Bruijn, J. F. Jongkind, M. I. Cleton-Soeteman, R. P. Apkarian, E. S. Gelsema

Scanning Microscopy

Structural and compositional analysis of isolated horse-spleen ferritin particles was performed by energy filtering transmission electron microscopy (EFTEM). Ferritin particles were collected in ultrathin (2 nm thick) chromium films and analyzed without any additional stain by electron energy-loss spectroscopy (EELS) for iron and carbon and by electron-spectroscopic imaging (ESI) for carbon. The ultrastructure of the proteinaceous shell of the ferritin particle, as obtained by the carbon net-intensity electron spectroscopical and carbon concentration-distribution images, was qualitatively compared to the structure as acquired by a negative-staining procedure.

Quantitative analysis of the number of carbon atoms in the ferritin-shell proteins was carried out …

Influence Of A Corpus Luteum Tissue Extract On Rabbit Ovarian Mesothelial Cells, S. V. Nicosia, R. J. Narconis, B. O. Saunders

Scanning Microscopy

This study investigates rabbit ovarian mesothelial (OM) cells exposed in vitro to a crude corpus luteum extract (CLE; 60 μg/ml). The growth of OM cells was evaluated by measuring the change in cell number (mean % ± standard error of mean, SEM), the number of cell population doublings (CPD ± SEM), and the cell population doubling time in hours (CPDT ± SEM) after 7.5 days of culture in a serum-poor medium. Quantitative estimates of surface morphology changes were obtained by analyzing the total number (mean no. ± SEM), density (mean no./100 μ.m² ± SEM), and length-to-diameter ratio (mean L/D …

Distribution Of Ca-Atpases In The Medial Habenula In Mouse, A. Kittel

Scanning Microscopy

The aim of this study was to investigate the distribution of the ecto-Ca,Mg-adenosine-triphosphatases (ecto-Ca,Mg-ATPases) in the medial habenular nucleus. Nerve terminals that seemed to be similar in morphological terms showed a different distribution of enzyme activity. Also, synapses showed a different distribution of enzyme activity. This could be related to the involvement of different neurotransmitters and modulators.