bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integrated microscopy resource for biomedical research at the university of wisconsin at madison
Authors: Schatten G. , Pawley J. , Ris H. 
Published: June 2020

The High Voltage Electron Microscopy Laboratory [HVEM] at the University of Wisconsin-Madison, a National Institutes of Health Biomedical Research Technology Resource, has recently been renamed the Integrated Microscopy Resource for Biomedical Research [IMR]. This change is designed to highlight both our increasing abilities to provide sophisticated microscopes for biomedical investigators, and the expansion of our mission beyond furnishing access to a million-volt transmission electron microscope. This abstract will describe the current status of the IMR, some preliminary results, our upcoming plans, and the current procedures for applying for microscope time.The IMR has five principal facilities:1.High Voltage Electron Microscopy2.Computer-Based Motion Analysis3.Low Voltage High-Resolution Scanning Electron Microscopy4.Tandem Scanning Reflected Light Microscopy5.Computer-Enhanced Video MicroscopyThe IMR houses an AEI-EM7 one million-volt transmission electron microscope.
Recent developments and controversies in the ultrastructural pathology of tumors
Authors: Henderson Douglas W. 
Published: June 2020

Fundamental aspects of the diagnostic fine structure of tumors are covered in detail in standard works on this topic, and will not be reiterated here. Instead, this presentation concentrates on selected recent developments and controversies in tumor ultrastructure.The distinction of epithelial mesothelioma from adenocarcinoma and of sarcomatoid mesothelioma from fibrohistiocytic sarcomas is a well-known problem in surgical pathology. In contrast to the short microvilli found in adenocarcinomas, mesothelial cells are typified by numerous elongated complex microvilli (MV), and a characteristic interdigitation of the MV with stromal collagen fibres may be seen in some cases - which I have never encountered in an adenocarcinoma. Estimation of the microvillus length:diameter ratio (MLDR) is now widely used in the evaluation of suspected mesotheliomas; values exceeding 11 are considered suggestive of mesothelioma, whereas lower values are usually found in adenocarcinomas.
Technical notes on routine TEM procedures
Authors: Chien K. , Van de Velde R.L. , Heusser R.C. 
Published: June 2020

Sectioning quality of epoxy resins can be improved by the addition of a 1% silicone 200 fluid (Dow Corning), however this produces a softer block. To compensate, a harder plastic has been used for embedding various tissues encountered in our pathology laboratory. Exact amounts of the plastic mixture can be directly made up for embedding as shown:
The chart reveals a Poly/Bed 812 (WPE 145) to anhydride ratio of 1:0.7 and a NMA to DDSA ratio of 7:3. 1% silicone fluid is added to above mixtures.Due to impurities within the DDSA and NMA, the polymerized epoxy blocks vary in darkness and appear to affect sectioning quality. After discussing this problem with Polysciences Inc., they have agreed to purify their anhydrides in an effort to standardize the consistency of the plastic.
Ultrarapid cooling and molecular distillation drying for sample preparation
Authors: Linner J.G. , Livesey S.A. , Harrison D.S. , Schifani T.A. 
Published: June 2020

The efficacy of electron microscopy as a tool to answer biochemical structure-function questions relates directly to the changes induced during sample preparation. Limitations of conventional methods include: slow penetration and crosslinking
by fixative, aqueous extraction, solvent extraction and chemical modification by crosslinking agent. Advantages include: stability of resin embedded sections and the
opportunity for repeated analysis. The aim of this study has been to develop and apply a technique of sample preparation which minimizes the limitations while maintaining the advantages of a resin embedded section. The method is divided into four components i.e., ultrarapid cooling, molecular distillation drying, vapor phase osmication and direct resin infiltration in vacuo.Ultrarapid cooling was obtained by the use of the metal mirror technique. Tissue samples (1mm3) or cultured cells grown on Therminox plastic were mounted on sample holders designed to minimize compression.
A time comparison circuit in the electric fish midbrain
Authors: Carr C. E. 
Published: June 2020

The weakly electric fish Eigenmannia is able to detect temporal disparities as small as 400 nanoseconds between two signals from different parts of the body surface. The elements of this time comparison circuit have been identified by EM reconstruction of its component cells.Information about the timing of the zero-crossings of signals on each area of the body surface is coded by phase coder receptors, a subset of tuberous electroreceptors. Electroreceptors on the body surface are innervated by primary afferents with a central termination on the spherical cells of the medullary electrosensory lateral line lobe. These cells project to lamina IV of the midbrain torus, a structure similar to the inferior colliculus. Afferents entering lamina VI form a very restricted terminal arbor in which they synapse upon the three cell types of this lamina.
Microcircuitry of the cat retina: Connections between arrays of neurons
Authors: Freed Michael A. , Sterling Peter 
Published: June 2020

One of the most basic of structure-function relationships in the mammalian visual system is the relationship between the size of a ganglion cell's receptive field and the number of rod photoreceptors which are connected to it. There is also the flip side of the coin: how many ganglion cells does a single photoreceptor connect to? We have estimated the number of rods which converge upon an on-beta type of retinal ganglion cell; we have also estimated the number of on-beta ganglion cells which a single rod diverges to. Our method is to extract a three-dimensional circuit from a series of two-dimensional electron microscope sections. The results have implications for the preservation of the signal/noise ratio in the ganglion cell.There are two well-documented routes from the rods to the on-beta ganglion cell.
Polychlorinated biphenyl induced hepatocyte alterations
Authors: Collins D.N. , Turner J.N. , Brosch K.O. , Seegal R.F. 
Published: June 2020

Polychlorinated biphenyls (PCBs) are a ubiquitous class of environmental pollutants with toxic and hepatocellular effects, including accumulation of fat, proliferated smooth endoplasmic recticulum (SER), and concentric membrane arrays (CMAs) (1-3). The CMAs appear to be a membrane storage and degeneration organelle composed of a large number of concentric membrane layers usually surrounding one or more lipid droplets often with internalized membrane fragments (3). The present study documents liver alteration after a short term single dose exposure to PCBs with high chlorine content, and correlates them with reported animal weights and central nervous system (CNS) measures. In the brain PCB congeners were concentrated in particular regions (4) while catecholamine concentrations were decreased (4-6). Urinary levels of homovanillic acid a dopamine metabolite were evaluated (7).Wistar rats were gavaged with corn oil (6 controls), or with a 1:1 mixture of Aroclor 1254 and 1260 in corn oil at 500 or 1000 mg total PCB/kg (6 at each level).
Extracellular filaments in the perineurium of the florida lobster,Panulirus argus
Authors: Baerwald Roy J. , Williamson Lura C. 
Published: June 2020

In arthropods the perineurium surrounds the neuropile, consists of modified glial cells, and is the morphological basis for the blood-brain barrier. The perineurium is surrounded by an acellular neural lamella, sometimes containing scattered collagen-like fibrils. This perineurial-neural lamellar complex is thought to occur ubiquitously throughout the arthropods. This report describes a SEM and TEM study of the sheath surrounding the ventral nerve cord ofPanulirus argus.JuvenileP. arguswere collected from the Florida Keys and maintained in marine aquaria. Nerve cords were fixed for TEM in Karnovsky's fixative and saturated tannic acid in 0.1 M Na-cacodylate buffer, pH = 7.4; post-fixed in 1.0% OsO4in the same buffer; dehydrated through a graded series of ethanols; embedded in Epon-Araldite; and examined in a Philips 200 TEM. Nerve cords were fixed for SEM in a similar manner except that tannic acid was not used.
Visualization in the EM of the intermediates in the actin-myosin ATPase cycle prepared by a rapid-freezing/stopped-flow method
Authors: Pollard T.D. , Bhandari D. , Maupin P. , Weeds A.G. , Huxley H.E. 
Published: June 2020

Motion and force are produced by myosin and actin in muscle and nonmuscle cells when myosin heads move along the surface of actin filaments. The energy is provided by the hydrolysis of ATP on the head of the myosin molecule. The details of the molecular motion in the myosin crossbridge have resisted characterization, in part because the crossbridge act asynchronously, even in the semicrystalline array of filaments found in striated muscles. Consequently, averaging techniques, including spectroscopic methods, tend to record a blurred signal from a large population of crossbridges.One way to circumvent this problem is :to examine individual myosin heads as they go through their cycle of ATP hydrolysis on the surface of the actin filament. The heads of myosin are large enough to image by EM, but the low affinity of active crossbridges for actin filaments complicates the situation.
Psammomatous duodenal carcinoid producing somatostatin: Ultrastructural investigation
Authors: Ilse G. , Kovacs K. , Gardiner G. , Moore T. 
Published: June 2020

Somatostatin producing duodenal psammomatous carcinoids, described first by Kaneko et al. in 1979, are rare. We have studied such a tumor by histology, immunohistochemistry, transmission electron microscopy, immunoelectron microscopy and energy dispersive x-ray microanalysis.A 60-year-old woman with attacks of biliary pain underwent cholecystectomy. At surgery, a tumor measuring 3 cm in diameter was discovered in the wall of the duodenum. Transduodenal biopsy revealed a psammomatous carcinoid exhibiting strong immunopositivity for somatostatin. The tumor was removed 4 months later. By histology, the tumor showed a tubular pattern as well as a cribriform arrangement, contained amorphous hematoxylinophil deposits and psammoma bodies which were positive with the von Kossa method and alizarin red. The avidin-biotin-peroxidase complex technique demonstrated positivity for somatostatin, mAB lu-5 (a monoclonal panepithelial antibody), keratin, neuron specific enolase and chromogranin. No immunoreactivity was obtained for ACTH, calcitonin, endorphin, FSH, gastrin, glucagon, GH, insulin, LH, neurophysin, PP, PRL, serotonin, α-subunit, VIP and vasopressin.
A freeze fracture technique for examining human hair medulla with Scanning and Transmission Electron Microscopy
Authors: Coble D. W. , Kairinen E. O. 
Published: June 2020

Examination of hair medulla by transmission electron microscopy (TEM) is difficult because of the keratinous composition of hair and because of sectioning problems that result from insufficient infiltration and nonmiscibility of hair with embedding resins, even those of low viscosity. Although longitudinally cutting or tearing fibers will expose the medulla for embedment or direct viewing, considerable disruption occurs in its structure. Less disruption results from the use of freeze fracture techniques for either transmission or scanning electron microscopy (SEM).Freshly plucked human scalp and beard hairs were submersed in liquid nitrogen for a minimum of three minutes, held at proximal and distal ends with Dumont #10 tweezers, and slowly bent to an arc until the specimens broke at the apex. Customarily, clean bevelled fractures occurred along the tips of the arcs and exposed not only the medulla but also the cortex and cuticle. The fractured specimens were then removed from liquid nitrogen.
Ultrastructural studies of the effect of cystamine on primary rat proximal tubular cell (PTC) cultures
Authors: Koizumi K. , Nishihira T. , Elliget K. A. , Phelps P. C. , Berezesky I. K. , Trump B. F. 
Published: June 2020

Cystamine has been shown to alter intracellular Ca2+ homeostasis in isolated perfused rat liver and isolated hepatocytes by inhibiting Ca2+ efflux. This inhibition of the active extrusion of Ca2+ from hepatocytes is associated with the formation of mixed disulfides between cystamine and plasma membrane thiols and a subsequent inactivation of Ca2+-ATPase. The resulting sustained increase in cytosolic free Ca2+ is followed by both proteolysis and phospholipid hydrolysis, the proposed mechanism of hepatotoxicity.We have investigated cystamine-induced nephrotoxicity in PTC primary cultures. This study reports ultrastructural changes in kidney cells resulting from exposure to 10 mM cystamine for 15, 60, 120 and 180 min.Primary tubular cells were isolated from male Fischer 344 rat kidney cortex and maintained in a 50:50 mixture of DME and Ham's F12. Four day-old cultures were treated with cystamine, washed twice with HBSS, fixed in 4% phosphate-buffered formaldehyde:1% glutaraldehyde, post-fixed is OsO4, dehydrated through an ethanol series and embedded in Polybed 812. Ultrathin sections were examined in a JEOL 100B electron microscope.
Bacterial cell damage by the complement system of channel catfish, Ictalurus punctatus
Authors: Rosell-Davis Rosemarie , Jenkins Jill A. , Coons Lewis B. , Ourth Donald D. 
Published: June 2020

The alternative complement pathway (ACP) provides the non-immune channel catfish with protection against many Gram-negative bacteria. The role of serum complement against Gram-negative bacteria is death of cells by insertion of the membrane attack complex (C5b-9) into the cell membrane. The assembly of the membrane attack complex is generated by the ACP and is activated by bacterial cell wall components. Pseudomonas fluorescens is a pathogen of channel catfish. In this study, bacteria were examined after incubation with catfish serum by scanning and transmission electron microscopy (SEM and TEM) for ultrastructural evidence of cell envelope damage by the complement system.A percent bactericidal assay determined that catfish plasma was 99% bactericidal against a 24 h culture of P. fluorescens (ATCC 13525). Following a 1 h incubation at 30°C of bacterial dilutions with equal volumes of serum, heat-inactivated serum, zymosan-adsorbed serum, or saline, the bacterial cells were filtered onto 0.22 um nuclepore filters, fixed in glutaraldehyde, dehydrated in ethanol, critical point dried, sputter coated with 15 nm gold and imaged using a JEOL SEM.
Improved preservation of the otolithic membranes
Authors: Cohen G. M. , Grasso J. S. , Domeier M. L. , Mangonon P. T. 
Published: June 2020

Any explanation of vestibular micromechanics must include the roles of the otolithic and cupular membranes. However, micromechanical models of vestibular function have been hampered by unresolved questions about the microarchitectures of these membranes and their connections to stereocilia and supporting cells. Otolithic membranes are notoriously difficult to preserve because of severe shrinkage and loss of soluble components. We have empirically developed fixation procedures that reduce shrinkage artifacts and more accurately depict the spatial relations between the otolithic membranes and the ciliary bundles and supporting cells.We used White Leghorn chicks, ranging in age from newly hatched to one week. The inner ears were fixed for 3-24 h in 1.5-1.75% glutaraldehyde in 150 mM KCl, buffered with potassium phosphate, pH 7.3; when postfixed, it was for 30 min in 1% OsO4 alone or mixed with 1% K4Fe(CN)6. The otolithic organs (saccule, utricle, lagenar macula) were embedded in Araldite 502. Semithin sections (1 μ) were stained with toluidine blue.
Electron microscopic study of age-related changes in the spleen of the cat
Authors: Faroon O. M. , Henry R. W. 
Published: June 2020

The spleen is involved in several immunological and physiological activities. The spleen serves as a “reservoir” of red blood cells, and their rapid release is correlated with the development of the capsule and the trabeculae. The spleen is a site of hematopoietic activity in the early stages of life. Investigations of age-related changes in megakaryocytopoiesis has been conducted on the rat spleen. Age-dependent changes which influence the microenvironment may lead to a decrease in the hematopoiesis and lymphocytic response. The decrease of immune response in aged animals has been investigated.The decline of immunological activity in animals and humans, increases susceptibility to infectious disease and malignancy. Splenic structure and age-related changes has been studied in rats and other mammalian species. However, there is no information on the changes which occur with age in the spleen of the cat. Therefore, this preliminary study, using cats of varying ages (prenatal to adult), was done to prepare for a quantitative study.
Chromosome banding in cultured cells transformed by polyoma virus
Authors: Mazzone H. M. 
Published: June 2020

Chromosome banding procedures commonly employ treatment steps in order to visualize the bands. In various cases, band-positive regions of chromosomes are observed after the latter are exposed to, e.g., acids, bases, salts, heat, or enzymes. Recently, mouse chromosomes treated with the antibiotic actinomysin D and the dye acridine orange demonstrated high resolution G-banding patterns by light microscopy. However, occasionally, banding can be produced with little or no treatment of the chromosomes. The present report describes the presence of bands in chromosomes of cultured cells whereby no treatment steps, as noted above, were employed. It is interesting that the history of the cells included their transformation by polyoma virus.Maintenance of virus-transformed Syrian hamster cell lines and their examination in the transmission electron microscope (TEM) was done in the Department of Biology of the Massachusetts Institute of Technology.
Plant Pathology Diagnosed by X-Ray Microanalysis
Authors: Resau J. H. , Howell N. , Chang S. H. 
Published: June 2020

Spinach grown in Texas developed “yellow spotting” on the peripheral portions of the leaves. The exact cause of the discoloration could not be determined as there was no evidence of viral or parasitic infestation of the plants and biochemical characterization of the plants did not indicate any significant differences between the yellow and green leaf portions of the spinach. The present study was undertaken using electron microscopy (EM) to determine if a micro-nutrient deficiency was the cause for the discoloration.Green leaf spinach was collected from the field and sent by express mail to the EM laboratory. The yellow and equivalent green portions of the leaves were isolated and dried in a Denton evaporator at 10-5Torr for 24 hrs. The leaf specimens were then examined using a JEOL 100 CX analytical microscope. TEM specimens were prepared according to the methods of Trump et al.
Liquid crystalline order of biopolymers in cuticles and bones
Authors: GIRAUD-GUILLE Marie-Madeleine 
Published: June 2020

The two major polymers of animal skeletal structures are chitin, a polysaccharide associated with proteins in arthropod cuticles, and collagen the main protein of bone. Electron microscopic studies, with the use of a goniometric stage, have shown that in biological tissues, the three-dimentional arrangement of these biopolymers often follow liquid crystalline geometries. Moreover highly concentrated solutions of purified collagen molecules spontaneously form close assemblies known as cholesteric phases. These results suggest that the determinism of supramolecular order in many extracellular matrices could well correspond to liquid crystalline assembly principles.The crab cuticle first allowed to establish an analogy between the fibrous chitin-protein network and the arrangement of molecules in cholesteric liquid crystals. The demonstration was obtained by tilting, in the electronic microscope, sections showing a typical pattern consisting of series of nested arcs (Fig.1). The suppression, or even better the inversion of arcs, validates the cholesteric model where the fibrillar directions, all parallel to the epidermis, rotate continuously from one plane to the next when moving outwards (LIVOLANT et al, 1978).
Cryo-TEM of micelles and lyotropic liquid crystals in non-aqueous solvents
Authors: Lin Zuchen 
Published: June 2020

Surfactant molecules can form spherical micelles in water above the critical micellization concentration. At still higher concentrations, they can form thread-like micelles and liquid crystals. Cryo-transmission electron microscopy of these microstructures in water is now used successfully for studying aqueous biological and synthetic systems. The controlled environment vitrification system (CEVS) makes it possible to prepare samples accurately. Further, The on-grid processing makes specimens possible from evolving systems halted in mid-process.Despite all the successes with aqueous systems, imaging of microstructures formed in non-aqueous solvents has not been reported. The main difficulties are radiation damage, thermal drift of the specimen, and low contrast. As small a spot size and as well spread a beam as possible are needed for low magnification searching. During the image recording, the minimum dose and lowest magnification possible are desired in order to avoid the thermal drift and radiation damage while maintaining an adequate signal-to-noise ratio.
Epithelial cell morphology on titanium implant surfaces
Authors: Laffoon John E. , Keller J.C. , Zaharias R. 
Published: June 2020

Previous work has indicated that the in vitro attachment and morphology of epithelial cells derived from oral mucosa are affected by substrate morphology. These findings have importance for dental implants in order to maintain an intact permucosal seal for the prevention of peri-implant disease similar in etiology to periodontitis. Since current dental implants have a variety of surface compositions ana morphologies, a more complete understanding of this tissue/implant interface is required.Discs of titanium, representing implant surfaces, were polished through 600 grit SiC papers or were polished thru lμm diamond paste to prepare grooved or smooth specimens respectively for SEM studies. For complimentary TEM studies of cell/substrate interfaces, standard tissue culture plastic was polished with 600 grit paper or was left intact prior to the application of a thin sputtercoated layer of titanium. All specimens were sterilized by exposure to UV light prior to the in vitro studies. Gingival and/or buccal epithelial cells derived from adult rat oral mucosa were maintained in FAD culture media supplemented with 10% fetal bovine serum.