Biology Commons^™

The Appearance Of Endothelium In Small Arteries After Treatment With 5-Fluorouracil. An Electron Microscopic Study Of Late Effects In Rabbits, M. Cwikiel, J. Eskilsson, J. B. Wieslander, U. Stjernquist, M. Albertsson

Scanning Microscopy

Cardiotoxicity is an unexplained toxic manifestation of 5-fluorouracil (5-FU). Its possible mechanism could be a direct cytotoxic effect on the vascular endothelium. We have tested this hypothesis in an experimental study in rabbits, using scanning and transmission electron microscopic evaluation of endothelium in small arteries (the central artery of the ear). The perfusion fixation method at physiological pressure and temperature was used. Both local and systemic effects of 5-FU on endothelium were studied 1, 3, 7, 14 and 30 days after in vivo treatment with 5-FU. Fifteen rabbits were used and five additional animals served as controls. The following parameters …

Impact Of The Incubation Medium On The Endothelium Of Autologous Vein Grafts: Damage Scoring By Scanning Electron Microscopy, M. A. Konerding, M. Knocks, H. -R. Zerkowski

Scanning Microscopy

The aim of this study was to examine the influence of different incubation media on the morphology of the endothelium of great saphenous vein grafts and establish a suitable scoring system for the evaluation of damage caused by these media. Fifty specimens of saphenous veins from ten patients during elective aorto-coronary bypass surgery were used. Ten specimens served as controls; the others were assigned to test groups and exposed to heparinized whole blood, Bretschneider's HTK, human albumin or Ringer's solution. Specimens exposed to heparinized blood showed only slight morphological alterations, whereas the other three mediums caused severe damage. Thus, heparinized …

Spiral Structures In The Wall Of The Hepatic Venous System In The Dog, Shigenori Okada, Yoshikuni Ohta

Scanning Microscopy

Unique spiral structures, located in the wall of the hepatic venous system in the dog, were examined in the central veins and the hepatic venous branches, utilizing microvascular corrosion casting and freeze-fracture technique in scanning electron microscopy and transmission electron microscopy of tissue sections. The whole hepatic venous system was divided into 4 portions: the central, sublobular, collecting and branches of the hepatic veins. The central vein was spindle-shaped with several compressions. Removing the endothelial cells of the central vein, pathways of venous sinusoids were like a labyrinth. In the sublobular veins, spiral structures distinctly appeared as the diameter increased. …

Microprobe Analysis Of Element Distribution In Rabbit And Dog Erythrocytes As Examples Of "High" And "Low" Potassium Cells, H. R. Catchpole, M. B. Engel

Scanning Microscopy

The concentrations of Na, Mg, P, S, Cl, K and Fe were determined by microprobe in near 100% hematocrit suspensions of rabbit and dog erythrocytes prepared by freezing and drying. These cells are representative, respectively, of "high" potassium, "low" sodium, and "high" sodium, "low" potassium cells. Water contents of the cells were the same, as were, approximately, the levels of Cl, S and Fe. Rabbit P was nearly double that of the dog. For the rabbit, the cell Na/K ratio was 0.21 and for the dog 15.4, illustrating the major diffusible electrolyte difference between these two types of cell. The …

Apoptosis And Red Blood Cell Echinocytosis: Common Features, Alexei B. Chukhlovin

Scanning Microscopy

Apoptosis of nucleated blood cells induced by oxidants and/or reactive oxygen species is accompanied by the typical membrane pathology. Meanwhile, red blood cell (RBC) membrane. is a popular object for studying appropriate cytotoxic effects. Scanning electron microscopy provides a reliable tool for detecting the oxidative changes in RBC shape and size. Transition of normal discoid erythrocytes to crenated forms (echinocytes) is often induced by the same factors which cause apoptosis of blood cells, e.g., ionizing radiation and other reactive oxygen intermediate-inducing agents, exogenous oxidants, in vitro aging conditions, cytosolic calcium increase, etc. Moreover, the biochemical membrane alterations in oxidant-induced echinocytosis …

Pathological And Immunocytochemical Changes In Chronic Calcium Oxalate Nephrolithiasis In The Rat, R. De Water, E. R. Boeve, P. P. M. C. Van Miert, C. P. Vermaire, P. R. W. A. Van Run, L. C. Cao, W. C. De Bruijn, F. H. Schroder

Scanning Microscopy

In the present study, we exposed rats to a crystal-inducing diet (CID) consisting of vitamin D3 and 0.5% ethylene glycol (EG), and we investigated histologically the kidney damage induced by the deposition of calcium oxalate (CaOx) crystals. After 28 days, 50 % of the animals had renal CaOx crystals, of which 60% also had small papillary stones. Most crystals were present in the cortex. The occurrence of these crystals coincided with morphological and cytochemical changes: glomerular damage, tubular dilatation and necrosis, and an enlargement of the interstitium. The number of epithelial and interstitial cells positive for the proliferating cell nuclear …

Touch-Plate And Statolith Formation In Graviceptors Of Ephyrae Which Developed While Weightless In Space, Dorothy B. Spangenberg, Elisa Coccaro, Russell Schwarte, Brian Lowe

Scanning Microscopy

Ultrastructural studies of the statocysts and touch-plates of graviceptors (rhopalia) of Aurelia ephyrae revealed that (1) touch-plate hair cells are present; and (2) cytoplasmic strands from the hair cell bases extend from the neurite plexus to touch similar strands from the lithocytes. This close association of hair cell neurites and statocysts may have important implications regarding the transmitting and processing of positional information with respect to the gravity vector.

Graviceptors of ephyrae which developed while weightless in microgravity were compared with controls at the ultrastructural level. We found that hair cells of ephyrae which developed in microgravity had fewer lipid …

Ion Beam Induced Charge Microscopy Of Integrated Circuits, M. B. H. Breese

Scanning Microscopy

The ion beam induced charge (IBIC) microscopy technique has recently been developed as a means of imaging the depletion regions of working microelectronic devices beneath their thick metallisation and passivation layers. IBIC microscopy is analogous to electron beam induced current microscopy but has the advantages of a larger analytical depth, lower lateral scattering of the incident focused MeV ion beam and negligible charging effects. These characteristics enable IBIC to image small, buried active device regions without the need to remove the surface layers prior to analysis. The basis of this new technique is outlined and the applications for integrated circuit …

Lectin-Cytochemistry Of Experimental Rat Nephrolithiasis, W. C. De Bruijn, R. De Water, E. R. Boeve, P. R. W. A. Van Run, P. J. Vermaire, P. P. M. C. Van Miert, J. C. Romijn, C. F. Verkoelen, L. C. Cao, F. H. Schroder

Scanning Microscopy

Lectin reactivity in epithelial apical cell coats of normal rat kidneys was compared to that from animals subjected to crystal inducing diets (CID). The aim was to see whether the absence of lectin reactivity in cell coats is related to intratubular calcium oxalate crystal retention. In normal rat kidneys, after a pre-embedding procedure, it was observed that at the ultrastructural level, reactivity was present but that the lectin specificity for the various parts of the nephron might have to be reconsidered. There was heterogeneity between the epithelial cells with respect to the presence of coat material in the tubular cell …

Atomic Force Microscopy Of Dna, Nucleoproteins And Cellular Complexes: The Use Of Functionalized Substrates, Yuri L. Lyubchenko, Robert E. Blankenship, Alexander A. Gall, S. M. Lindsay, Ottavio Thiemann, Larry Simpson, Luda S. Shlyakhtenko

Scanning Microscopy

Progress towards rapid and simple characterization of biomolecular samples by scanning probe microscopy is impeded mainly by limitations of the current approach to sample preparation. We are working on approaches based on chemical functionalization of mica. Treatment of mica with aminopropyltriethoxy silane (APTES) makes the surface positively charged (AP-mica) and able to hold DNA in place for imaging, even in water. We have shown that AP-mica is an appropriate substrate for numerous nucleoprotein complexes as well. The AFM images of the complex of DNA with RecA protein are stable and indicate a structural periodicity for this filament. AP-mica holds strongly …

Imaging Molecular Structure Of Channels And Receptors With An Atomic Force Microscope, Ratneshwar Lal

Scanning Microscopy

Biological membranes contain specialized protein macromolecules such as channels, pumps and receptors. Physiologically, membranes and their constituent macromolecules are the interface surfaces toward which most of the regulatory biochemical and other signals are directed. Yet very little is known about these surfaces. The structure of biological membranes has been analyzed primarily using imaging techniques that are limited in their resolution of surface topology. An atomic force microscope (AFM) developed by Binnig, Quate and Gerber, can image molecular structures on specimen surfaces with subnanometer resolution, under diverse environmental conditions. Also, AFM can manipulate surfaces with molecular precision: it can nanodissect, translocate, …

In Vitro Systems And Cultured Cells As Specimens For X-Ray Microanalysis, Godfried M. Roomans, Jarin Hongpaisan, Zhengzhu Jin, Ann-Christin Mörk, Ailing Zhang

Scanning Microscopy

In vitro systems and cultured cells are recognized as useful systems in many areas of biomedical research, including X-ray microanalysis. To be reliable, in an vitro system should have an elemental composition close to that of the tissue in situ, react in the same way to stimuli, and retain the in situ regulation of ion transport. In the present paper, four of the most commonly used in vitro systems will be reviewed: incubated tissue slices (liver and pancreas), isolated glands (submandibular gland acini, sweat glands), primary cell cultures (sweat glands, endometrium), and cell lines (the colon cancer cell line …

Accessing Nuclear Structure For Field Emission, In Lens, Scanning Electron Microscopy (Feisem), T. D. Allen, G. R. Bennion, S. A. Rutherford, S. Reipert, A. Ramalho, E. Kiseleva, M. W. Goldberg

Scanning Microscopy

Scanning electron microscopy (SEM) has had a shorter time course in biology than conventional transmission electron microscopy (TEM) but has nevertheless produced a wealth of images that have significantly complemented our perception of biological structure and function from TEM information. By its nature, SEM is a surface imaging technology, and its impact at the subcellular level has been restricted by the considerably reduced resolution in conventional SEM in comparison to TEM. This restriction has been removed by the recent advent of high-brightness sources used in lensfield emission instruments (FEISEM) which have produced resolution of around 1 nanometre, which is not …

Angiogenesis In The Gonadal Capillary Network Of The Chick Embryo, F. J. Pérez-Aparicio, A. Carretero, M. Navarro, J. Ruberte

Scanning Microscopy

Seventy-one chick embryos of both sexes at the 35 Hamburger and Hamilton (H-H) developmental stage were processed for scanning electron microscopy of vascular corrosion casts and of critical point dried specimens, as well as transmission electron- and light microscopy, in order to study the angiogenic structures. The gonadal subepithelial capillary network was located at the level of the tunica albuginea under the covering epithelium. The casts showed a densely-meshed capillary network and numerous sprouting (nodular protrusions or capillary sprouts) and non-sprouting (enlarged vessels and angiogenic holes) angiogenic structures that were randomly distributed and mixed. Four types of angio-genic holes were …

Micrographic Fracture Characterization Of Gallium Arsenide Wafers, H. E. Belsinger Jr., L. D. T. Topoleski, B. Wilner

Scanning Microscopy

Single crystal gallium arsenide (GaAs) specimens were loaded to failure. Scanning electron microscope examination of fracture surfaces showed that GaAs fails in a brittle manner on {110} planes. Features on these fracture surfaces were used to identify preexisting (critical) flaws that potentially initiated fracture when loaded by tensile stresses. Critical flaws in each specimen were identified by comparison to an intentionally damaged control. The size and shape of critical defects were consistent with existing failure models.

Tc-Mapping And Investigation Of Water-Initiated Modification Of Yba2cu3o7-X Thin Films By Low Temperature Scanning Electron Microscopy, A. V. Bobyl, M. E. Gaevski, S. G. Konnikov, D. V. Shantsev, V. A. Solov'ev, R. A. Suris

Scanning Microscopy

The T_c -mapping method using low temperature scanning electron microscopy (LTSEM) has been developed to study the spatial distribution of the critical temperature in high temperature superconducting (HTSC) films with a spatial resolution approaching 2 μm. To achieve so high a spatial resolution, a numerical deconvolution method was applied that eliminated distorting effects associated with the thermal diffusion and with the contribution from the absorbed beam current. The T_c -mapping method was used to investigate modification by water of YBa₂Cu₃O_7-x films grown on (100) MgO and (110) LaAIO₃ substrates. The rate of …

Crystallization During Volume Reduction Of Solutions With An Ion-Composition Corresponding To That In The Distal Tubuli, Inge Hojgaard, Anne-Marie Fornander, Mari-Anne Nilsson, Hans Goran Tiselius

Scanning Microscopy

The effect of macromolecules on the crystallization in solutions with an ion-composition and a pH corresponding to that of urine in the distal part of the distal tubuli was examined by recording the number and volume of crystals in a Coulter Multisizer and by studying the crystal morphology with scanning electron microscopy at different degrees of evaporation. The experiments were carried out with 100 ml samples of salt solutions with and without different concentrations of dialysed urine (dU) from normal subjects. Addition of dU resulted in a greater number of crystals and a reduction in the mean crystal volume (MCV). …

A Yohimbine-Dependent, Uk14,304 Induced Ion Transient In Ht29 Cells Studied By X-Ray Microanalysis, Wei Zhang, Godfried M. Roomans

Scanning Microscopy

The response of HT29 cells to α₂-adrenoceptor agonists was investigated by X-ray microanalysis. Treatment of the cells with 10 μM UK14,304, an α₂-agonist, resulted in a rise of intracellular Cl and Na, suggesting an antisecretory effect. When the cells were exposed to yohimbine or RX821002, both of which are arantagonists, the former had no effect, whereas the latter produced a minor decrease of the cellular Na, Cl and K concentrations. However, when the cells were pretreated with yohimbine, UK14,304 induced a transient change in ion concentrations, which consisted of a rapid increase of intracellular Cl, Na …

Cytoskeleton Architecture Of C6 Rat Glioma Cell Subclones Whole Mount Electron Microscopy And Immunogold Labeling, Wolfgang Bohn, Dörte Etzrodt, Roland Foisner, Gerhard Wiche, Peter Traub

Scanning Microscopy

Whole mount electron microscopy of extracted cells combined with immunogold labeling techniques can be used to characterize the cytoskeletal architecture of cultured cells. As shown with subclones of the C6 rat glioma cell line, heavy metal shadowing was suitable for getting basic information concerning the arrangement of the various filament types within the networks. Pure carbon shadowing combined with immunogold double labeling proved to be optimal to identify linkages between filaments, to localize filament associated proteins and to follow the arrangement of filaments in dense arrays such as lamellipodiae and cell margins. Thin connecting filaments which interact with actin as …

Imaging Soft Materials With Scanning Tunneling Microscopy, J. T. Woodward Iv, J. A. Zasadzinski

Scanning Microscopy

By modifying freeze-fracture replication, a standard electron microscopy fixation technique, for use with the scanning tunneling microscope (STM), a variety of soft, non-conductive biomaterials can be imaged at high resolution in three dimensions. Metal replicas make near ideal samples for STM in comparison to the original biological materials. Modifications include a 0.1 μm backing layer of silver and mounting the replicas on a fine-mesh silver filters to enhance the rigidity of the metal replica. This is required unless STM imaging is carried out in vacuum; otherwise, a liquid film of contamination physically connects the STM tip with the sample. This …

Experimental Measurements Of Electron Stopping Power At Low Energies, David C. Joy, Suichu Luo, Raynald Gauvin, Pierre Hovington, Neal Evans

Scanning Microscopy

The electron stopping power has been measured for twelve elements and fifteen compounds, over the energy range from 1 eV to 10 keV, by the analysis of electron energy loss spectra, optical data, and photon mass absorption data. Values of the effective mean ionization potential Jeff and the effective number of participating electrons Neff have also been determined in each case. The results obtained have been compared with other experimental data, with first-principles theoretical calculations, and with a number of proposed analytical models.

Energy Dispersive X-Ray Microanalysis Of The Dentin In Rat Molars After Corticosteroid Treatment, Karin Nasstrom, Rolf Odselius, Arne Petersson

Scanning Microscopy

The aim of this study was to investigate whether the calcium (Ca) and phosphorus (P) composition of corticosteroid induced dentin was the same as in normally developed dentin. Seven rats were given corticosteroids intravenously and three rats served as controls. Energy dispersive X-ray microanalysis (EDX) was carried out on the axially sawn roots of the molars. Measurements were made at 20 sites, equally distributed in the buccal, mesial, lingual and distal direction. The results showed that the Ca/P ratio (weight %) was slightly above 2.0 in both the experimental and the control group, indicating that the corticosteroid induced dentin had …

Patterns Of Calcium Oxalate Crystal Production By Three Species Of Wood Decay Fungi, Jon H. Connolly, Howard J. Arnott, Jody Jellison

Scanning Microscopy

Wood decay experiments using red spruce wood resting on moist soil were conducted to discern temporal and spatial patterns of calcium oxalate (CaOx) crystal production by three species of fungi over the course of decay. All three species produced crystals of calcium oxalate dihydrate, but not monohydrate, in and on wood. Over the course of decay, the production of CaOx crystals was shown to be heterogeneous in both space and time. The relative quantity, morphology and longevity of CaOx crystals varied among species. Gloeophyllum (G.) trabeum produced substantial quantities of "free" crystals; Fomitopsis (F.) pinicola produced encrusting crystals; and Trichaptum …

Atomic Force Microscopy Of Dna Electrophoresed Onto Silylated Mica, Irène Revenko, Helen G. Hansma

Scanning Microscopy

A new technique has been developed for electrophoresing DNA molecules from an agarose gel onto a silylated mica substrate where they can be imaged with an atomic force microscope (AFM). With a simple modification, the technique can also be used for polyacrylamide gels. This method does not require purification of samples from the gels. Using tapping mode AFM, we have observed plasmids after electrophoretic separation into two bands. Differences in conformation were observed between the plasmids in the two bands.

Regenerating Synovial Lining Of The Normal Rabbit Knee: A Scanning Electron Microscopy Study, Haim Stein, Daniel Levanon

Scanning Microscopy

Regeneration of the synovial lining in the synovectomized rabbit knee was studied using the scanning electron microscope. The resected synovia regenerated considerably 3 weeks after synovectomy. However, 44 weeks following excision, their surface morphology was still very different from that of the normal tissue of intact animals. The regenerated synovia were characterized by three main features: the large number of various patterns, the many fields harboring fibrillation and the almost total lack of a bubble layer (the latter was formerly shown to be predominant on normal, intact synovia). The surface morphology of the non-operated (contralateral) knee differed greatly from that …

Determinants Of Weddellite Formation: Chondroitin Sulfates And Citrate Determine Weddellite Formation In Vitro, Kookmin M. Kim

Scanning Microscopy

In synthetic urine (SU), addition of oxalate tends to form monohydrates of calcium oxalate. However, addition of oxalate to natural urine preferably forms calcium oxalate dihydrate (COD). Urine apparently contains a determinant for COD formation. To identify the determinant, the effects of pH, temperature, oxalate, calcium, urate, citrate, magnesium, sulfate and chondroitin sulfates (CS) on calcium oxalate crystal formation were studied. Lower temperatures, higher oxalate concentrations and higher pH favored COD formation in a SU. Mixed CS in the presence of citrate were the most decisive determinant of COD formation. Substitution of CS for agar and gelatin produced similar results, …

Potential Sputtering Of Protons With Slow Multiply Charged Ions, Yasunori Yamazaki, Nobukazu Kakutani

Scanning Microscopy

Experimental findings of insulator sputtering with slow multiply charged ions are reviewed with particular emphasis on proton sputtering, including recent studies which pay attention not only to the yields, but also to the energy distributions of sputtered particles. A simplified scenario of multiply charged ion interaction with a solid surface is discussed, which consists of two stages, i.e., resonant charge transfers well above the surface (the stage I), and a violent collision with the surface transferring a major part of the potential energy (the stage II). A couple of processes relating to the sputtering in the stages I and II …

Effects Of Ionizing Radiation On Cartilage: Emphasis On Effects On The Extracellular Matrix, M. Cornelissen, H. Thierens, L. De Ridder

Scanning Microscopy

In this report, we review data dealing with radiation effects on cartilage. More specifically, we emphasize on alterations caused in the extra-cellular cartilage matrix. Although radiation studies predominantly describe the effect on the structure of DNA and on the mitotic activity of cells, alterations caused by the effect on the non-mitotic activity can also be important. Cartilage, having an extracellular matrix composed of 2 major components, aggrecan and collagen, provides a good model to study this kind of radiation effects. The following topics concerning literature data are summarized: effects on the amount of matrix synthesized, effects on the activity of …

The Nucleation And Growth Of Calcium Phosphate Crystals At Protein And Phosphatidylserine Liposome Surfaces, G. H. Nancollas, A. Tsortos, A. Zieba

Scanning Microscopy

The kinetics of calcium phosphate crystal growth at the surfaces of proteins and phospholipids has been investigated using free drift and constant composition methods in supersaturated calcium phosphate solutions (relative supersaturations: with respect to hydroxyapatite, HAP, σHAP = 15.0, and with respect to octacalcium phosphate, OCP, σOCP = 1. 9). Fibrinogen and collagen molecules adsorbed at hydrophobic surfaces as well as uncross-linked collagen fibrils induce ion binding and subsequent nucleation of calcium phosphate. The formation of OCP on phosphatidylserine vesicles introduced to highly supersaturated calcium phosphate solutions probably involves the interaction of the calcium ions with the ionized carboxylic groups …

Ionizing Radiation-Induced Apoptosis And Dna Repair In Murine Erythroleukemia Cells, R. Di Pietro, L. Centurione, E. Santavenere, M. A. Centurione, G. Sanitá Di Toppi, L. Zamai, R. Rana

Scanning Microscopy

A morphological study of DNA repair and apoptotic patterns in relationship with cell cycle events was performed on murine erythroleukemia cells. The presence and distribution of DNA replicon sites were evaluated through the BrdU-anti BrdU immunofluorescence and immunogold techniques in light and electron microscopy. Different patterns of labelling and percentages of BrdU positive cells were observed depending on irradiation dose (up to 60 Gy) and time in post-irradiation culture (up to 24 hours). An enlargement of the S phase of the cell cycle was evidenced 18 hours post-irradiation as determined by flow cytometry analysis. The high resolution approach showed that, …