bluuebunny/crossref_metadata_2025_split huggingface dataset:
An ultrastructural study of hairy-cell leukemia: Report of one case in a Chinese
Authors: Chew E. C. , Li C. L. , Lee K. W. , Chow C. H. , Huang D. P. , Saw D. , Ho J. H. C. 
Published: June 2020

Hairy cell leukemia is a rather rare malignant lymphoreticular disorder. In U.S.A. Bouroncle gave a case incidence of approximately 2% of all leukemias. In China only a few cases have been reported according to a monograph entitled 'Leukemia' written in Chinese by a grout) of authors working in the Haematology Laboratory of the First Hospital affiliated to the Medical University of Wuhan. Recently, a case has been discovered in a Chinese in Singapore (Shannugaratnam*) and probably another in Taiwan (Huang*). We report here a case in whom the hairy cells have been studied by scanning and transmission electron microscopies.For TEM, lymphoid cells isolated from peripheral blood by ficoll solution and centrifugation were fixed in 2.5% glutaraldehyde for 1 hour. Routine procedures were followed for dehydration and embedding in Spon 812. The stained sections were examined with a Philips EM 300 at 60 kV. For SSM, the pre-fixed specimens were dehydrated, critically dried, coated with goldpalladium and examined with a Cambridge Stereoscan 150 EM at 20 kV.
Effect of trypsin in the presence or absence of Ca2+ on tight junction in an epithelial cell line
Authors: Polak-Charcon Sylvie , Pitelka Dorothy R. 
Published: June 2020

Recent studies indicate that adhesion between cells is mediated by at least two different surface sites, one Ca2+-dependent and one Ca2+-independent. The first is highly sensitive to trypsin in the absence of Ca2+ but resistant in the presence of Ca2+, whereas inactivation of the second requires higher trypsin concentrations and Ca2+ has no effect on proteolysis.Tight junctions (TJ) in vertebrate epithelia provide a transepithelial permeability barrier, help to maintain cell polarity, and also are strongly adhesive. Trypsin and other proteases are often used in cell dissociation protocols but are known in several epithelia to induce TJ proliferation. Our previous study of LA7, a rat mammary epithelial cell line, showed as demonstrated by others that withdrawal of Ca2+ leads to disruption of TJ. The effect of trypsin on LA7 cells in the absence or presence of Ca2+ was studied to determine whether TJ are related to the Ca2+-dependent mechanism of cell adhesion in epithelia.
Examination of lysozyme CH crystals by low-dose electron microscopy
Authors: Robinson J.P. , Jeng T.W. , Chiu W. , Hash J.H. 
Published: June 2020

Lysozyme Ch is an extracellular bacteriolytic enzyme produced by a species of fungus that has been provisionally classified as Chalaropsis. This enzyme has been isolated in pure form with a combination of ion-exchange chromatography and salt fractionation and has been physically characterized and completely sequenced. Circular dichroic measurements indicate a high content of beta-structure. It has a molecular weight of 22415 and contains a single disulfide bond. Lysozyme Ch is distinctly different from the lysozymes of avian egg whites, bacteriophages, plants, and invertebrates. Part of the interest in lysozyme Ch stems from its specificity. In addition to having β-1,4-N-acetylmuramidase activity in common with other lysozymes, it also has β-l,4-N,6-0-diacetylmuramidase activity. It is therefore active against bacterial species that have 6-0-acetylmuramic acid in their cell wall peptidoglycans; e.g., Staphylococcus aureus.Lysozyme Ch crystallizes from 45% ammonium sulfate solution and to date crystals in habits suitable for X-ray crystallography have not been obtained. Therefore the available crystals have been examined by electron microscopy. The ammonium sulfate in which the crystals are formed is replaced with ammonium acetate which is more volatile for specimen preparation.
Two-dimensional arrays of membrane-bound (Na+, K+) - ATPase
Authors: Mohraz M. , Kivisild K.L. , Simpson M.V. , Rinder C.A. , Smith P.R. 
Published: June 2020

(Na+, K+) - ATPase is a trans-membrane protein which utilizes energy from ATP hydrolysis to transport K+ into the cell and Na+ out of the cell against the concentration gradient of both of these ions. It consists of a catalytic subunit (α, M.W. 100,000) and a glycoprotein chain (β, M.W. 40,000). It is however, uncertain if the B structure or an oligomeric (αβ)2 structure forms the minimum active unit. The sequence information on the α and β-subunits is also incomplete. Therefore information about the structure of the enzyme should prove helpful in answering some of the outstanding questions about its function.(Na+, K+) - ATPase was purified in membrane-bound form from the outer medulla of pig and dog kidneys according to the procedure of P.L. Jorgensen. The activity measurements and polyacrylamide gel electrophoresis indicated that the preparations were 75-85% pure.
Localization of lipoyl-bearing domains in 2-ketoglutarate dehydrogenase complex by electron microscopy and single-particle averaging methods
Authors: Wagenknecht Terence , Frank Joachim 
Published: June 2020

The 2-ketoglutarate dehydrogenase complex (KGDC) from E. coli (Mr=2.5 x 106) consists of multiple copies of three component enzymes. In addition to its catalytic function one of the components, dihydrolipoyl transsuccinylase (E2), serves as a structural core (Mr=l x 106) to which the other two components are noncovalently bonded. X-ray diffraction studies have shown the E2 complex to be built from 24 identical polypeptide chains and to have the overall shape of a cube having truncated corners. In the electron microscope the E2 complexes adhere preferentially to the support surface by one of their faces and thus appear square-shaped with four morphological units at the vertices and a stain filled center (Fig 1A).Each of the E2 chains contains a lipoic acid cofactor covalently linked to a lysine residue. A domain (Mr=ll,000) containing the lipoyl moiety is removed by trypsin without disrupting the basic architecture of the complex. Micrographs of the trypsin-treated E2 complexes (Fig 1B) appear similar to those of the native complexes (Fig 1A), although the trypsintreated complexes appear slightly smaller and have a more sharply defined 4-fold symmetry.
A structural study of modified fibrinogen and fibrin
Authors: Hewat E. A. , Tranqui L. , Wade R. H. 
Published: June 2020

A knowledge of the form of the fibrinogen molecule and the structure of fibrin are clearly essential to the understanding of their role in the coagulation of vertebrate blood. The elongated multinodular form of the molecule is well established, but its detailed form and the structure of the fibrin fibre have remained controversial. Our approach to this problem has been firstly to examine the form of the molecule in several types of microcrystals of proteolytically modified fibrinogen. Tilting experiments enabled identification of the same molecular form in two different crystalline forms (P21212 and P21). Two projections of the molecule at 0° and at 37° to the 2-fold molecular axis were obtained from the two principal plane projections of the two crystal forms. This information enabled a rough determination of the relative heights of the different subdomains of the molecule. Hence we are able to propose a more detailed model of the fibrinogen molecule than has previously been reported.Secondly, to clarify the existence of any differences between the native and the modified fibrinogen molecule, we examined individual molecules using negative staining and shadowing techniques.
Beryllium skin granuloma: Identification by electron energy loss spectroscopy
Authors: Mehard C. W. , Epstein W. L. 
Published: June 2020

Understanding granulomatous inflammation includes the sequential biochemical and cytological changes which occur following tissue insult or injury. Granulomas may arise as a foreign body response to a colloidal substance involving a simple phagocytic process or as a hypersensitivity phenomena involving the reticuloendothelial system. We report here on the localization and detection of beryllium (Be) in Be-induced skin granulomas. Visualization and elemental analysis of Be, element number, was carried out by scanning transmission electron microscopy and electron energy loss spectroscopy.Foreign body skin granulomas were produced by injecting beryllium lactate subdermally in the upper arms and shoulders of volunteers. Biopsies were taken 6-8 weeks later, fixed in 2% glutaraldehyde, dehydrated in ethanol and embedded in epon. Some specimens were post fixed in osmium tetroxide, dehydrated in a graded, series of ethanol and embedded in epon. Thin sections (500Å-2000Å) were viewed at 100 Kv, unstained in a Hitachi K-60G STEM, equipped with EDS and EELS.
Effects of ciglitazone on the pancreatic islets of C57BL/6J-OB/OB mice: Qualitative electron microscopy of beta cells and quantitative light microscopy of islet surface area and number
Authors: Peterson T. , Sawada G. , Wyse B. , Gilchrist B. , Diani A. 
Published: June 2020

The Ob/Ob mouse of the genetic background C57BL/6J is characterized by obesity, hyperglycemia, insulin resistance, and hyperplasia of the pancreatic beta cells. Under electron microscopy, the beta cells from this animal model display degranulation, proliferation of the rough endoplasmic reticulum, and expansion of the Golgi apparatus, all of which are indicative of a stressed pattern of insulin storage and synthesis.Ciglitazone has been reported to function as an oral hypoglycemic agent in the 0b/0b mouse. This depression of plasma glucose was associated with a significant elevation in pancreatic insulin as observed in our laboratory after six weeks of drug treatment (100 mg/kg-day incorporated into Purina Mouse Chow). Pancreatic islets of treated and age-sex matched control C57BL/6J-Ob/Ob mice were then analyzed by ultramorphology and light microscopy to determine the effect of ciglitazone on beta cells. Under electron microscopy, the pancreatic beta cells of treated mice were well granulated with rare abnormalities of the citoplasmic organelles and insulin secretory granules occupied most of the cytoplasm of the islet - cells.
An ultrastructural morphometric analysis of platelet giant and fusion granules in control subjects and patients with neoplastic myeloproliferative disorders
Authors: Payne Claire M. , Glasser Lewis 
Published: June 2020

Electron microscopy has made a significant contribution to our understanding of the normal and defective human platelet. The normal human platelet is ultrastructurally complex and although only 2-4 microns in diameter, contains many cell organelles and structural elements shared with muscle cells and neurons. Platelet organelles include mitochondria, microfilaments, microtubules, α-granules (contain fibrinogen and platelet factor 4), dense bodies (contain serotonin, ADP, ATP and calcium), a dense tubular system and open canalicular system (Fig. 1). An ultrastructural description of giant granules were first reported in 1960 in Willebrand-Jürgens disease. Fusion granules (giant, irregularly-shaped granules) resulting from an apparent "fusion of normal-sized α-granules have since been reported to be characteristic of platelets obtained from patients with preleukemia and myelomonocytic leukemia.Electron microscopic examination of normal platelets in our laboratory revealed occasional granules which also appear fused and irregular in shape.A qualitative assessment of what constitutes an abnormal granule is therefore subjective. The purpose of this study was to establish morphometric criteria which can be used to define the pathological nature of giant and fusion-type platelet granules, and to determine if patients with neoplastic myeloproliferative disorders can be distinguished from patients with a variety of benign conditions for diagnostic purposes.
Z-line degradation and phagocytosis of sarcomeric fragments in myonecrosis
Authors: Estes Melinda L. , Chou Samuel M. 
Published: June 2020

Many muscle diseases show common pathological features although their etiology is different. In primary muscle diseases a characteristic finding is myofiber necrosis. The mechanism of myonecrosis is unknown. Polymyositis is a primary muscle disease characterized by acute and subacute degeneration as well as regeneration of muscle fibers coupled with an inflammatory infiltrate. We present a case of polymyositis with unusual ultrastructural features indicative of the basic pathogenetic process involved in myonecrosis.The patient is a 63-year-old white female with a one history of proximal limb weakness, weight loss and fatigue. Examination revealed mild proximal weakness and diminished deep tendon reflexes. Her creatine kinase was 1800 mU/ml (normal < 140 mU/ml) and electromyography was consistent with an inflammatory myopathy which was verified by light microscopy on biopsy muscle. Ultrastructural study of necrotizing myofiber, from the right vastus lateralis, showed: (1) degradation of the Z-lines with preservation of the adjacent Abands including M-lines and H-bands, (Fig. 1), (2) fracture of the sarcomeres at the I-bands with disappearance of the Z-lines, (Fig. 2), (3) fragmented sarcomeres without I-bands, engulfed by invading phagocytes, (Fig. 3, a & b ), and (4) mononuclear inflammatory cell infiltrate in the endomysium.
Possibility of Single Atom Resolution in Single-Sideband Imaging
Authors: Downin K. H. 
Published: June 2020

The ability to distinguish between heavy and light components of a specimen, and especially to distinguish single heavy atoms, would be a great benefit in many instances. Even with the demonstrated ability of the STEM, and of the CTEM especially in dark field, to image single atoms, it is of interest to know the possibility of using bright field in a conventional microscope with subsequent image processing to obtain images of single heavy atoms separated from the image of a lighter supporting film.Single-sideband image reconstruction, involving the combination of two images obtained using opposite halves of the diffraction pattern, offers in principle the ability to separate images of heavy and light specimen components, or specimen components giving rise to amplitude and phase contrast, respectively. This has been demonstrated in electron microscopy^, but under conditions or low resolution, where inelastic scattering, as well as scattering outside the effective objective aperture, contribute heavily to the component with amplitude contrast.
Lattice Imaging of Stacking Faults in (011) Silicon
Authors: Krivanek Ondrej L. , Maher Dennis M. 
Published: June 2020

Thermal oxidation of silicon containing surface defects results in the formation of extrinsic stacking faults inhabiting the (111) planes. The faults are bound by Frank partial dislocations, and oxygen may be closely associated with them. The present work aims to explore the fault core structure by lattice imaging.The p-type, 4 Ω-cm Si was boron implanted (50kV, 1x1015/cm2), annealed for 30 min at 1000°C and steam oxidized for 2 hours at 1050°C. The boron implantation prior to oxidation serves to produce a high density of stacking faults to facilitate their observation. The polished and thinned (011) foils were examined at 125kV in a Siemens 102 EM with a goniometer stage at magnifications of 500 000 to 800 000x, using axial illumination and no objective aperture.
Experiments with a Quadrupole Octopole Corrector in a STEM
Authors: Beck V. 
Published: June 2020

Recently a number of experiments have been carried out on a STEM which included a multipole corrector for primary spherical aberration. The results of these experiments indicate that the correction of primary spherical aberration with magnetic multipoles is beset with very serious difficulties related to hysteresis.The STEM and corrector have been described previously. In theory, the corrector should cancel primary spherical aberration so that other aberrations limit the resolution. For this instrument, secondary spherical aberration should limit the resolution to 1 A at 50 kV. A thorough study of misalignment aberrations was made. The result of the study indicates that the octopoles must be aligned to 1000 A. Since mechanical alignment cannot be done to this accuracy, trim coils were built into the corrector in order to achieve the required alignment electrically. The trim coils are arranged to excite all the lower order moments of an element.
Electron Optical Studies Of Catalyzed Gasification Of Graphite
Authors: Szirmae A. , Shirley C.G. , Fisher R.M. 
Published: June 2020

The pronounced catalytic effect of small particles of iron and other elements and compounds on the reaction of carbonaceous solids with various gases (02, CO-CO2, H20-H2) has been documented by a number of investigators reporting on thermogravimetric studies on bulk samples (1,2) and on optical and electron microscope observations of pitting or surface channeling by rapid local attack adjacent to sub-micron iron particles (3,4). In this work, emphasis has been placed on detailed electron microscope studies of Fe particle channeling on graphite exposed to “wet” and “dry” hydrogen at temperatures from 650°C to 1200°C.Flakes of freshly cleaved Ticonderoga graphite are coated with 40 - 1000 Å of Fe by vacuum deposition which forms spherical particles during subsequent annealing at 750°C.
The Suitability Of The Lattice Fringe Imaging Technique For Measuring Spatial Variation In Degree Of Long-Range Order In Fe-Al Alloys
Authors: Allen Samuel M. 
Published: June 2020

A computer simulation of lattice fringe imaging of ordered Fe-Al alloys has been carried out, using the multiple beam dynamical theory of electron diffraction as formulated by Sinclair et al. for CU3AU (1). The object of the study was to determine the suitability of the lattice fringe imaging technique for studying spatial variations in long-range order parameter in singlephase ordered specimens.In the interest of simplicity, the results of simulations in which eight beams were excited in the (200) systematic row for an imperfectly B2-ordered alloy of composition Fe-25% aluminum will be presented. (The prototype crystal structure for the FeAl phase is CsCl.) Simulated images were obtained by combining the direct beam with the (100) superlattice reflection, for the case in which Bragg's Law was satisfied for the (100) reflection, and with both beams equidistant from the optic axis of the microscope.Image intensities as a function of distance parallel to [200] were computed for different specimen thicknesses and long-range order parameters.
Interpretation Of Dark FIELD IMAGES OF CRYSTALS
Authors: Iijima Sumio , O'Keefe M. A. 
Published: June 2020

In order to determine whether image contrast of dark field images of crystals can be interpreted intuitively in terms of crystal structures, in the same way as for bright field images, observations and calculations have been made on the dark field images of a crystal of 4Nb205.9W03(Fig. 1, space group P21212, tetragonal tungsten bronze-type,a= 12.3,b= 36.6,c= 3.9Å). Disorder in this crystal will be duscussed elsewhere (IT). To verify the present state of the art of theoretical interpretation of bright field images, we compared an experimental structure image (Fig. 3a) with one calculated (Fig. 3b) taking into account various parameters including the beam divergence. Low resolution images were also compared (Figs. 3c,d). Matching between the images is satisfactory. From this basis we developed a computer program for dark field images of crystals.To simplify the interpretation we confine ourselves here to low resolution images, i.e., number of beams contributing to the image is less than 15 (position of the objective aperture is indicated in the E.D. pattern of Fig. 2a).
Scanning Electron Microscopy of Human Jejunum in Whipple's Disease
Authors: Watson John H. L. , Sun C. N. 
Published: June 2020

That the etiology of Whipple's disease could be bacterial was first suggested from electron micrographs in 1960. Evidence for binary fission of the bacteria, their phagocytosis by histiocytes in the lamina propria, their occurrence between and within the cells of the epithelium and on the brush border of the lumen were reported later. Scanning electron microscopy has been applied by us in an attempt to confirm the earlier observations by the new technique and to describe the bacterium further. Both transmission and scanning electron microscopy have been used concurrently to study the same biopsy specimens, and transmission observations have been used to confirm those made by scanning.The locations of the brush borders, the columnar epithelial cells, the basement membrane and the lamina propria beneath it were each easily identified by scanning electron microscopy. The lamina propria was completely filled with the wiener-shaped bacteria, Fig. 1.
Biological and Surface Properties of C-Type Virus Particles Produced by Novikoff Ascites Hepatoma Cells
Authors: Hixson D.C. , Chan J.C. , Bowen J.M. , Walborg E.F. 
Published: June 2020

Several years ago Karasaki (1) reported the production of type C virus particles by Novikoff ascites hepatocarcinoma cells. More recently, Weinstein (2) has reported the presence of type C virus particles in cell cultures derived from transplantable and primary hepatocellular carcinomas. To date, the biological function of these virus and their significance in chemically induced hepatocarcinogenesis are unknown. The present studies were initiated to determine a possible role for type C virus particles in chemically induced hepatocarcinogenesis. This communication describes results of studies on the biological and surface properties of type C virus associated with Novikoff hepatocarcinoma cells.Ecotropic and xenotropic murine leukemia virus (MuLV) activity in ascitic fluid of Novikoff tumor-bearing rats was assayed in murine sarcoma virus transformed S+L- mouse cells and S+L- mink cells, respectively. The presence of sarcoma virus activity was assayed in non-virus-producing normal rat kidney (NRK) cells. Ferritin conjugates of concanavalin A (Fer-Con wheat germ agglutinin (Fer-WGA), and Ricinus communis agglutinins I and II (Fer-RCAI and Fer-RCAII) were used to probe the structure and topography of saccharide determinants present on the viral envelope.
Immunocytochemical Localization of Amyloid Protein AA in the “Dense Fibrillar Inclusions” of the Reticuloendothelical Cells
Authors: Shirahama T. , Skinner M. , Cohen A.S. 
Published: June 2020

A1thought the mechanisms of amyloidogenesis have not been entirely clarified, proteolysis of the parent proteins may be one of the important steps in the amyloid fibril formation. Recently, we reported that "dense fibrillar inclusions" (DFI), which had the characteristics of lysosomes and contained organized fibrillar profiles as well, were observed in the reticuloendothelial cells in close association with the foci of new amyloid deposits. We considered the findings as evidence for the involvement of lysosomal system in amyloid fibril formation (l). In the present study, we attempted to determine the identity of the contents of the DFI by the use of antisera against the amyloid protein (AA) and an immuno-electron microscopic technique.Amyloidosis was induced in CBA/J mice by daily injections of casein (l). AA was isolated from amyloid-laden spleens by gel filtration and antibody to it was produced in rabbits (2). For immunocytochemistry, the unlabeled antibody enzyme method (3) was employed.