Life Sciences Commons^™

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 …

The Motile Behavior Of Virus-Transformed 3t3 Cells, Guenter Albrecht-Buehler

Scanning Electron Microscopy

Using metallic gold in various assays for the motility of cultured tissue cells, the paper compares the movements of surface projections and the locomotion of polyoma (Py3T3) and SV40 (SV3T3) virus-transformed 3T3 cells with the behavior of the parental 3T3 cells.

The movement of surface projections was assayed by the ability of filopodia, lamellipodia and blebs of freshly plated cells to remove colloidal gold particles from a particle-coated glass substrate. The ability of filopodia to probe the environment for points of anchoraqe was tested by observing cells plated on glass whose filopodia touched the surface of a neighboring area of …

Statolith Formation In Cnidaria: Effects Of Cadmium On Aurelia Statoliths, D. B. Spangenberg

Scanning Electron Microscopy

Statolith formation in Cnidaria was reviewed with an emphasis on Aurelia statoliths. The review provides information on the chemical composition, mechanisms of initiation of mineralization, and effects of environmental factors on Cnidarian statolith formation. Environmental factors discussed include modified sea water ingredients, X-irradiation, clinostat rotation, and petroleum oil ingredients. A detailed account of the effects of cadmium on mineralization and demineralization of Aurelia statoliths is given. Cadmium at dosages of 2 to 4 μM significantly reduces statolith numbers in developing ephyrae. At a dosage of 3 μM, cadmium accelerates statolith loss in unfed ephyrae studied at 4 and 8 days …

High Sensitivity Ion Microscopy: A Tool For Material Science Research, N. A. Thorne, A. Dubus, F. Degrève

Scanning Electron Microscopy

Direct ion imaging is a strong point of the CAMECA IMS 3f ion microscope, but has undergone little commercial development. A modified image acquisition system is presented which incorporates a high sensitivity video camera allied with a rapid image digitizer/processor. Individual ion impacts on the channel plate are detected at maximum gain and image sensitivity is effectively increased to that of the mass spectrometer. For intermediate (10³ to 10⁵) and low (<10³) count rates image processing such as averaging or integration is essential to improve the poor detection statistics and allow real time image formation. …

Solder Characterization On Ancient Gold Artifacts With The Electron Microprobe, A. R. Duval, C. Eluere

Scanning Electron Microscopy

The Laboratoire de Recherche des Musees de France has tested the applicability of the scanning electron microscope with X-ray analysis facilities in the study of ancient gold artifacts and particularly the joining processes. Three types of joining methods are known to have been used in Ancient Times : sintering, brazing with Au-Ag-Cu alloys and copper-salt binding. X-ray distribution maps of selected elements on very small areas show clearly the different processes used in the manufacture of Oriental and Iron-Age artifacts.

Scanning Electron Microscopy Of Thebesian Ostia (Microdissection By Ultrasonication: Enzymatic Digestion), F. A. Rosinia, F. N. Low

Scanning Electron Microscopy

Thebesian vasculature provides for communication between the coronary system and the chambers of the heart. Anatomic, embryologic, physiologic, and therapeutic investigations have involved this component of cardiac anatomy from the early 18th century to the present time. The scanning electron microscope (SEM) now affords an innovative approach to the study of the ostia of these veins as they open into the chambers of the heart. The surface of the intact endocardium is continuous, whether it is treated with boric acid or not, as long as it remains intact. Enzymatic microdissection of tissues with trypsin, hyaluronidase and pronase, followed by similar …

Otoconia As Test Masses In Biological Accelerometers: What Can We Learn About Their Formation From Evolutionary Studies And From Work In Microgravity?, Muriel D. Ross, Kathleen M. Donovan

Scanning Electron Microscopy

This paper reviews previous findings and introduces new material about otolith end organs that help us to understand their functioning and development. In particular, we consider the end organs as biological accelerometers. The otoconia are dealt with as test masses whose substructure and evolutionary trend toward calcite may prove significant in understanding formation requirements. Space-flight helps illuminate the influence of gravity, while right-left asymmetry is suggested by study of certain rat strains.

Surface Ultrastructure Of Human Megakaryocytes Sorted On The Basis Of Dna Content, M. A. Weller, J. Szela, M. I. Barnhart, A. Nakeff

Scanning Electron Microscopy

The relationship of polyploidization (DNA content) to differentiation is not well defined. We have developed centrifugal elutriation and Percoll density gradient centrifugation to obtain larye numbers of highly-purified mega-karyocytes which subsequently were stained for DNA content with Hoechst 33342 and sorted by FACS into SC, 16C and 32C ploidy classes for correlated analysis of cell surface structures by scanning electron microscopy. Each ploidy class revealed unique surface characteristics that reflect differentiation occurring in megakaryocytes independent of their DNA content.

The Capillary Bed In The Choroid Plexus Of The Lateral Ventricles: A Study Of Luminal Casts, Enrico D. F. Motti, Hans-Georg Imhof, Robert C. Janzer, Klaus Marquardt, Gazi M. Yasargil

Scanning Electron Microscopy

Micro-angioarchitecture of the choroid plexus of the lateral ventricles is investigated in microcorrosion casts of animal and human preparations studied with the scanning electron microscope. The capillary bed in the diverse regions of the tissue belongs to one of three patterns: (1)-a network of capillary meshes that envelop the larger arteries and veins predominates in the central segment. (2)-in the villous regions a "leaf-like" organization of sinusoids is found together with (3)-fronds of "glomerular" formations. "Glomeruli" are formed when arterial afferents and venous efferents converge in a quasi hilar structure before branching in arterio-venous loops. Nodular thickenings are observed on …

The Gill Arch Of The Striped Bass, Morone Saxatilis. Ii. Microvasculature Studied With Vascular Corrosion Casting And Scanning Electron Microscopy, Judy A. C. King, F. E. Hossler

Scanning Electron Microscopy

The gill vasculature of euryhaline striped bass, Morone saxatilis, was examined by scanning electron microscopy of corrosion casts prepared by injecting resin (either Mercox/Sevriton or L.R. White) into the ventral aorta. The vasculature of the striped bass gill appears to be similar to that of other euryhaline species. The striped bass gill has three major vascular systems: (1) a respiratory system, (2) an arterio-venous system, and (3) a nutritive system. In the respiratory system, blood from the afferent branchial artery flows to each filament via an afferent filamental artery, and from there to the highly vascularized respiratory lamellae. Lamellar …

Phase Transitions Of Calcium Oxalate Trihydrate And Epitaxy In The Weddellite-Whewellite System, Sergio Deganello

Scanning Electron Microscopy

The phase changes calcium oxalate trihydrate-weddellite, weddellite-calcium oxalate monohydrate and calcium oxalate trihydrate-whewellite are individually examined at the atomic level from a theoretical point of view; concomitantly the topological requirements necessary for phase stability are clarified for each structure type. In solution a sequential series of phase transitions according to the steps calcium oxalate trihydrate-weddellite-whewellite is not likely to be energetically favoured; direct conversion of calcium oxalate trihydrate to whewellite should be, instead, ordinarily expected.

It is formally demonstrated that along two axial directions a set of atoms is in essentially identical positions in both weddellite and whewellite. This notwithstanding, …

Anatomy And Morphometry Of Myocardial Capillaries Studied With Vascular Corrosion Casting And Scanning Electron Microscopy: A Method For Rat Heart, F. E. Hossler, J. E. Douglas, L. E. Douglas

Scanning Electron Microscopy

The present paper describes a procedure for preparing vascular corrosion casts of rat myocardial microvasculature. Essential components of the procedure include: partial "self clearing" of the heart in vitro; cardiac arrest by infusion of KCl; retrograde aortic root infusion of Mercox-Sevriton casting resin; KOH digestion of ventricular tissue; and desiccation and mounting of casts for scanning electron microscopy. About 50% of rats yielded complete casts. Vasculature closely paralleled muscle fiber orientation. Capillary beds characteristically exhibited branching, many intercapillary cross bridges, and occasional coil-ing. Average capillary cast diameter (5.6 μm) and intercapillary distance (15 μm) are comparable to results from in …

Permanent Noise-Induced Damage To Stereocilia: A Scanning Electron Microscopic Study Of The Lizard's Cochlea, Michael J. Mulroy

Scanning Electron Microscopy

Alligator lizards were exposed to broadband noise ranging in intensity from 106 to 132 dB SPL for two hours and permitted to recover from 19 to 62 days. Hearing loss was assessed by comparing the auditory nerve component of the cochlear potential recorded at the end of the recovery period with that recorded before the noise exposure. The stereocilia in these ears were examined with a scanning electron microscope. These sensory hairs showed pathological changes similar to those described in mammalian cochleas with noise-induced damage. In decreasing order of severity the damage included completely missing auditory papillas, missing hair cells, …

The Biomineralization In Social Wasps (Vespinae): The Presence Of Statoliths, J. S. Ishay, T. Shimony, L. Arcan

Scanning Electron Microscopy

In social wasps granular aggregates occur mainly in the head region and the body integument. In the former location they are present both on the outer and inner side of the frons. On the outer side of the frons, in a groove traversing its center, there is a deep pit surrounded by a membrane which forms a cyst-like sac. In the pit of the hornet Vespa orientalis (Linne, 1771), there are aggregates comprising silicon (Sl), potassium (K), calcium (Ca) and iron (Fe), which are arranged in morula-like fashion. A granular material is secreted at the base of sensory hairs …

Effects Of Local Fields On Electron Beam Voltage Measurement Accuracy, J. L. De Jong, Jan D. Reimer

Scanning Electron Microscopy

Voltages at various levels have been measured on unpassivated aluminum lines in an integrated circuit (IC) test structure with widths and spacings ranging from 1.5 μm to 8 μm. For the measurements a pulsed electron beam (e-beam) system with 1 keV electrons was used in conjunction with a planar retarding field analyzer. Examination of the results shows that the voltage measurement accuracy is affected by local fields created by the potential differences between neighboring conductors on the IC. They also reveal how these fields and measurement errors are related to the conductor line width and spacing, the supply voltage level …

Genes, Manganese, And Zinc In Formation Of Otoconia: Labeling, Recovery, And Maternal Effects, L. C. Erway, N. A. Purichia, E. R. Netzler, M. A. D'Amore, D. Esses, M. Levine

Scanning Electron Microscopy

Published studies indicate that genes and dietary manganese deficiency cause vestibular defects and ataxic behaviors. Manganese deficiency during development causes otoconial defects in mice, rats, guinea pigs, and chicks. Mutant genes cause otoconial defects in mice, mink, and poultry. Manganese supplementation prevents the otoconial defects in some mutant mice and mink. Manganese is essential, before crystallization of the otoconia, for synthesis of mucopolysaccharides and otoconial matrix. Such defects can be induced, after otoconia are crystallized during fetal development, by dietary zinc deficiency and sulfonamide treatment (inhibits carbonic anhydrase, a zinc-requiring enzyme). Manganese and/or zinc supplementation ameliorates otoconial defects in pallid …

Topical Modes In The Preparation Of Human Spleen Specimens For Routine Scanning Electron Microscopy Studies, Haim Gamliel, Harvey M. Golomb, Eliezer Avinoah, Dorit Gurfel, Aaron Polliack

Scanning Electron Microscopy

Various preparatory techniques were used to improve scanning electron microscopy images of the fine structure of vascular, cellular, and cordal-reticular components of normal human spleens. The progressive method of fixation (GTGO) applied in the present study, allowed air drying of the tissues and rendered the specimens conductive even in newly fractured surfaces. Vascular perfusion proved necessary only in studies of the splenic blood vessels, while a simple immersion of tissue blocks in the washing solution resulted in better images of the white pulps. Interstitial (trans-splenic) perfusion was found to be superior to vascular perfusion for routine preparation of spleen tissues, …

Particle Probe Analysis In The Study Of Skin Physiology, Bo Forslind

Scanning Electron Microscopy

The basic function of provide a barrier which the epidermis is will separate the body compartment from the environment thus protecting the organism from excessive loss of water and to hinder the entrance of noxious agents. A continuous renewal of the actual barrier makes it possible to fulfill these requirements. Using particle probe analysis, electron microprobe (EMP) and proton microprobe (PMP) analysis we have demonstrated the feasibility of these techniques in the study of skin physiology. The results reported here have been obtained on quench frozen skin specimens inertly prepared by cryotechniques to produce freeze-dried sections presenting cross sections of …

Integrated Image And X-Ray Microanalysis Of Hepatic Lysosomes In A Patient With Idiopathic Hemosiderosis Before And After Treatment By Phlebotomy, M. I. Cleton, J. M. Roelofs, C. J. G. Blok-Van Hoek, W. C. De Bruijn

Scanning Electron Microscopy

Morphometrical and X-ray elemental information was extracted from Scanning Transmission Electron Microscopy (STEM) images of hepatic lysosomes of a patient with idiopathic hemosiderosis before and after treatment by phlebotomy. The elements of interest were (i) iron, stored in pathological quantities in hepatic lysosomal structures and (ii) cerium, used as a capture ion after a cytochemical reaction to detect acid phosphatase activity in the lysosomal structures.

Morphologically the lysosomal structures are heteromorph and the elements iron and cerium are heterogeneously distributed. With "reduced raster" (= reduced scanning area) analysis at 16 x 16 pixel points (integrating image and X-ray microanalysis), a …

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 …

Calcification In Aging Canine Aortic Valve, Kookmin M. Kim, S. H. Chang, B. F. Trump, H. Spurgeon

Scanning Electron Microscopy

Aging changes of aortic valves are thought to underlie the mechanism of calcification, which leads to calcific aortic stenosis in humans. The study of calcification in the aging valvular connective tissue has been hindered by the lack of a suitable animal model. In search of the model, canine aortic valves demonstrated age changes including calcification remarkably similar to those in humans. The mechanism of calcification was studied in the aortic valves of aged Beagles by electron microscopy. Fibroblasts in the canine aortic valves showed the most prominent age changes. The cells accumulated numerous residual bodies and appeared to disintegrate. The …

Use Of Cryogenically Prepared Samples In The Scanning Electron Microscopic Study Of Dry-To-Wet Transitions, John N. A. Lott, Patrice Kerr

Scanning Electron Microscopy

Cryogenic preparation has been used to study changes that occur as a dry specimen undergoes hydration. Conventional techniques such as critical point drying or anhydrous fixation are unsuitable for studying such changes. Seed tissue, a dry moss and various foods were chosen to show dry-to-wet transitions that take place after wetting of the dry sample begins. Cryogenically prepared specimens have great potential, not only in the study of changes which occur during imbibition of one sample, but also in the study of samples with different moisture content.

Scanning Electron Microscopic Features Of Spleen In The Rat And Human: A Comparative Study, S. Sasou, R. Satodate, T. Masuda, K. Takayama

Scanning Electron Microscopy

The marginal zone, white pulp and red pulp of rat and human spleen were studied by scanning electron microscopy and were compared. The marginal zone was observed in both species. The arterial termination in the marginal zone was quite different between both species. The follicular arteries terminated at the boundary of the white pulp and formed a vascular net regarded as the marginal sinus in rat. On the other hand, numerous arterial termini of the follicular and sheathed arteries were scatteringly found in the marginal zone in man. The central artery was surrounded with flat reticular cells in rat and …

The Developmental Features Of Marrow Stroma In Ectopic Bone Marrow Implants, Karla Harjes, Bettye Collier, Mehdi Tavassoli

Scanning Electron Microscopy

Implantation of bits of marrow in ectopic sites is followed by reorganization of tissue and the formation of a hemopoietic nodule surrounded by a shell of bone. This regenerative process is reminiscent of marrow ontogeny and the model can serve to study marrow ontogeny in a relatively short period of time. Early events during this regeneration were studied by scanning (SEM) and transmission electron microscopy (TEM). Within 24 hours the implant elicited an angiogenic reaction and new vessels penetrated the implant. Intense circulation, thus established, divested the implant from hemopoietic cells, leaving the stroma behind. Stromal cells proliferated and the …

Regulation Of Hematopoiesis In Long Term Marrow Cultures: Role Of Humoral Factors In The Proliferation And Differentiation Of Stem Cells And Committed Progenitors, Christine Elins Eastment

Scanning Electron Microscopy

Established systems of long-term bone marrow culture (LTBMC) have contributed to our understanding of the interrelationships between the adherent stromal cells and the stem cells, committed progenitors and mature terminally differentiated cells. While cell-mediated or short range stromal interactions appear to be a major source of homeostatic control between the stromal microenvironment and the stem cells, positive and negative humoral influences or long-range mechanisms also regulate stem cell proliferation and differentiation. Adherent stromal conditioned medium generates factors which can trigger CFU-s into DNA synthesis within 18 hours or inhibit incorporation of tritiated thymidine into rapidly proliferating CFU-s. Other adherent stromal …

Analysis Of Voltage-Contrast Decay On Passivated Devices Under Electron Beam Probing, Y. Watanabe, Y. Fukuda

Scanning Electron Microscopy

Voltage-contrast decay on passivated devices under electron beam probing has been reported. The dependence of the decay time constant of the voltage contrast on the primary electron current, the passivation thickness, and the dielectric constant of the passivation has been analyzed with a recently developed theory of capacitive-coupling voltage contrast. It is found that the theory can be used to estimate the time constant under various observation conditions. Deviation of the time constant from the prediction, depending on the size of the electron beam irradiated area, has been observed and interpreted as being due to secondary electron charging on the …

Scanning Electron Microscopy Of Kidney Cells In Culture: Surface Features Of Polarized Epithelia, J. A. Mcateer, G. S. Dougherty, K. D. Gardner Jr., A. P. Evan

Scanning Electron Microscopy

We have used scanning electron microscopy (SEM) to examine the surface morphology of the renal epithelial cell lines MDCK and LLC-PK1 to determine the influence of alternative culture substrate conditions on cell polarity. We observed that regardless of physical culture conditions, cells establishes and maintained polarity, expressed by the characteristics of apical and basal surfaces. culture conditions did, however, influence the orientation of cell polarity in vitro. MDCK cells were grown within collagen gel, in which individual cells exhibited clonal growth to form fluid-filled epithelial cysts. The cells of MDCK-cysts were polarized with apical surface facing the lumen and …

High Current Density Magnetic Electron Lenses In Modern Electron Microscopes, J. Podbrdský

Scanning Electron Microscopy

New possibilities for the application of high current density magnetic electron lenses in commercially produced electron microscopes are discussed. The optimum current density in the windings of a commercially produced instrument has been determined. An improved indirect water cooling arrangement with a closed, vibration-free, cooling circuit has been found to be a reliable and practical system. This has been made possible by a substantial improvement in the method of manufacturing wire coils, leading to a greatly increased heat transfer. The reduced dimensions of such. coils have made it possible to design a general purpose lens body, that is readily adapted …

A Finite Element Method For The Computation Of Magnetic Electron Lenses, Bohumila Lencová, Michal Lenc

Scanning Electron Microscopy

The success of computer-aided design in electron optics is no longer limited by computing facilities but by our understanding of numerical methods and underlying physical laws used for the computation. This paper deals mainly with the computation of vector potential in rotationally symmetric magnetic lenses. The finite element method, as introduced by Munro in 1971, seems to be the best tool for this purpose, and we aim to show in this paper how it is possible to improve it without losing the original clarity. Therefore we discuss the suitable choice of mesh and the calculation of the coefficients of the …

Optical Microreflectometry And Microscopy Of Chalcopyrite Specimens: Reflectance Calculation And Comparison To Backscattered Electron Microscopy, G. Remond, R. Caye, P. Ruzakowski, P. H. Holloway

Scanning Electron Microscopy

A model was developed to calculate the optical reflectance of an absorbing substrate covered by multiple thin layers of absorbing materials. Both multiple homogeneous thin layers and thin surface layers of mixed phases were modeled. Reflectance versus wavelength was measured for polished chalcopyrite (CuFeS₂) and compared to calculated data. The identity and thickness of surface compounds used to calculate reflectance curves were partially determined using X-ray photoelectron and Auger electron spectroscopies. Very good agreement between theoretical and experimental reflectance curves were observed as a function of surface composition. The hue (color) and luminosity (brightness) of the polished surface …