bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of aromatic hydrocarbons on the distribution of mucopolysaccharides associated with the gill and nasal mucosa
Authors: Norton W.N. , Mattie D.
Published: June 2020

Selective aromatic hydrocarbons such as benzene, xylene and naphthalene have been analyzed as to their relative toxicities to acquatic organisms. The aromatic hydrocarbon fraction of JP-4 jet aviation fuel, which consists of benzene, xylene and toluene induces cellular lesions in a variety of internal organs of the fat-head minnow.

The primary objective of the investigation was to determine the acute ultrastructural effects of the water soluble fraction of petroleum-derived JP-4 aviation fuel on the distribution of mucopolysaccharides normally associated with surfaces of the gill and nasal mucosa of the fat-head minnow. Ruthenium red, a hexavalent cation, was employed as a visual marker for the presence of mucopolysaccharides.

Fish were exposed to a 60% concentration of the water soluble fraction of JP-4. At the time periods of 2, 6 and 12 hours subsequent to the initial exposure, a select number of fish were removed from the solution and the gills and sections of the nasal mucosa were excised. The tissues were immersed for 1 hour in 0.1M cacodylate-buffered (pH 7.4) 2.5% glutaraldehyde containing 500 ppm ruthenium red.
Enumeration of microprocesses of T-lymphoma cells by two morphometric methods using SEM and TEM
Authors: Okagaki Takashi , Clark Barbara A. , Twiggs Leo B.
Published: June 2020

We have demonstrated that the number of pseudopodia is directly correlated with cell differentiation and carcinogenesis in the squamous epithelium. Microprocesses over T-lymphocytes may also reflect cell differentiation or a functional state of the cells as seen in the epithelial cell model, although their functions are not well understood. Visual quantification of spatially distributed bodies such as microprocesses observed with a scanning electron microscope (SEM) is inherently poor. That is, exact quantitation of the number of microprocesses per cell may be necessary to demonstrate a smaller difference in frequency of such structure. One drawback of previous attempts to use such a method was that the quantitation of a structure over a surface which was at a steep angle to the film plane could not be accurate. We developed a modified method of enumeration with SEM and another method with a transmission electron microscope (TEM), using cultured murine T-lymphoma cells (EL-4) as a model, and the results were compared.
Ultrastructural diagnosis of a plexiform liposarcoma
Authors: Siew Shirley , Jhaveri Bharati , Elsensety Evette
Published: June 2020

Less well differentiated malignant neoplasms may pose a serious problem in the establishment of a definitive diagnosis at the light microscopy level. In such instances, transmission electron microscopy (TEM) may prove to be of value as it may identify diagnostic characteristics that can be appreciated only at ultrastructural magnification. The case reported here illustrates the application of TEM in the differential diagnosis of a soft tissue sarcoma.

A 63 year old male presented in the out patient service with a mass in the region of the left scapula. Its gross appearance was likened to that of a "Big Mac." A needle biopsy was performed and submitted for histological and TEM examination. Histology of multiple serial sections showed the presence of a malignant neoplasm composed of markedly pleomorphic cells, including numerous bizarre giant cells and smaller cells with irregular nuclear outline and indistinct eosinophilic cytoplasm. Cytoplasmic vacuoles were prominent. They did not stain with PAS nor mucin stains.
3-D reconstruction of molecular shape from microcrystal thin sections
Authors: Cusack S. , J.-C. Jésior
Published: June 2020

Three-dimensional reconstruction techniques using electron microscopy have been principally developed for application to 2-D arrays (i.e. monolayers) of biological molecules and symmetrical single particles (e.g. helical viruses). However many biological molecules that crystallise form multilayered microcrystals which are unsuitable for study by either the standard methods of 3-D reconstruction or, because of their size, by X-ray crystallography. The grid sectioning technique enables a number of different projections of such microcrystals to be obtained in well defined directions (e.g. parallel to crystal axes) and poses the problem of how best these projections can be used to reconstruct the packing and shape of the molecules forming the microcrystal.

Given sufficient projections there may be enough information to do a crystallographic reconstruction in Fourier space. We however have considered the situation where only a limited number of projections are available, as for example in the case of catalase platelets where three orthogonal and two diagonal projections have been obtained (Fig. 1).
Tubular intranuclear inclusions in a patient with methotrexate-associated pulmonary fibrosis
Authors: Gunning W.T. , Goldblatt P.J.
Published: June 2020

A forty-six year old male, who had received methotrexate therapy for the past year for psoriasis of twenty years' duration, presented with a cough which had persisted for two to three months. There was a two year history of dyspnea upon exertion as well as intermittent fever, chills and sweats. The methotrexate treatment did not improve the skin condition and, because there was evidence of hepatic toxicity, the drug was discontinued. Radiological examination of the chest revealed diffuse bilateral interstitial fibrosis with extensive changes; a subseguent lung biopsy was obtained. Light microscopic evaluation demonstrated marked interstitial fibrosis, chronic inflammation, thickening of the alveolar septa, proliferation of alveolar macrophages, occasional fibrin deposits and multinucleated giant cells.

Electron microscopic studies revealed massive fibrosis with a mixed population of infiltrating inflammatory cells. Some alveolar spaces were lined by metaplastic cuboidal epithelial cells, and in numerous residual type II pneumocytes, aggregates of branching tubules lined by trilaminar membranes were identified within the nucleus.
Transmission electron microscope studies of a piliated strain of Haemophilus influenzae B
Authors: Palmer Booth Doris
Published: June 2020

The role of pili as a mucosal attachment factor that enhances colonization and pathogenicity is well known in Escherichia coli, Neisseria gonorrhea, Streptococcus pyrogenes and Proteus mirabilis. Although Haemophilus influenzae type b (Hib) causes serious infections in children such as meningitis, pneumonia, septic arthritis and epiglottitis, very little information is available about Hib piliation and subsequent adhesion and colonization in vivo. Hib piliation was recently correlated with hemagglutination and adherence (in vitro) to human buccal epithelial cells by Pichichero, et al.

Pili are protein structures which extend from the outer membrane of Hib. Purified pili have an apparent molecular weight of 23,000 daltons by Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and aggregate laterally as well as end on end to form thick filamentous structures. Although pili seem to enhance attachment to respiratory mucosa (a significant foothold during the invasion of healthy tissue) the relative pathogenicity of piliated and non-piliated Hib is yet to be determined.
Sensitivity of the Critical Voltage of Alloys to Composition and Short Range Order
Authors: Shirley C. G. , Fisher R. M.
Published: June 2020

Detailed examination of electron diffraction patterns from thick crystals at accelerating voltages greater than about 100 KV, has revealed that at certain critical voltages, Vc, second-order Kikuchi lines vanish and other characteristic changes occur (1,2). The value of Vc depends on the structure factors which, in turn, are sensitive to (a) redistribution of the outer atomic electrons in the crystalline environment, (b) composition and long-range order, (c) mean-square static and thermal displacements (m.s.d.) of the atoms. The manner in which the critical voltage(s) of a metal or an alloy vary with temperature, composition, and thermal history is potentially a very useful, and sometimes quite precise probe of the sub-microscopic state of the alloy or metal. However, the small number of critical voltages for any particular crystal, and the limited number of experimental variables (temperature, etc.) make it necessary to employ a model of the crystal which depends only on the most important parameters (3,4).
Electron Channeling Patterns
Authors: Joy David C.
Published: June 2020

Electron channeling patterns (ECP) were first found by Coates (1967) while observing a large bulk, single crystal of silicon in a scanning electron microscope. The geometric pattern visible was shown to be produced as a result of the changes in the angle of incidence, between the beam and the specimen surface normal, which occur when the sample is examined at low magnification (Booker, Shaw, Whelan and Hirsch 1967).

A conventional electron diffraction pattern consists of an angularly resolved intensity distribution in space which may be directly viewed on a fluorescent screen or recorded on a photographic plate. An ECP, on the other hand, is produced as the result of changes in the signal collected by a suitable electron detector as the incidence angle is varied. If an integrating detector is used, or if the beam traverses the surface at a fixed angle, then no channeling contrast will be observed. The ECP is thus a time resolved electron diffraction effect. It can therefore be related to spatially resolved diffraction phenomena by an application of the concepts of reciprocity (Cowley 1969).
Electron Wave Optical Identification of Specific Atoms in Thin Crystals
Authors: Uyeda N. , Kobayashi T. , Fujiyoshi Y. , Ishizuka K.
Published: June 2020

The Abbe's prediction about the ultimate resolution of lens acquired a deeper significance for the realization of new type of microscope when the diffraction of electrons was confirmed in accord with de Broglie's theory. However, it was only early 1970's that heavy atoms and well-defined molecules were brought to human eyes in spite of the tremendous progress in modern science. On the occasion of commemorating the 50th anniversary of electron diffraction, it may be worthwhile to note that the resolution of "microscope", which was once resigned to discouraging limitation, has been improved so surprisingly that even oxygen atoms in crystal lattice can be identified in some fortuitous case.
Low Temperature Annealing of Arsenic Implanted <111> Silicon
Authors: Kannan V. C.
Published: June 2020

When arsenic ions are implanted into silicon to a dose of 2xl014 ions/ cm2 or higher, the implanted surface becomes amorphous. The amorphous layer epitaxially recrystallizes back to the original substrate orientation upon annealing at or above 500°C. In the manufacture of integrated circuits and other devices, annealing is carried out at about 900°C in order to restore the electrical activity of implanted arsenic and also to obtain suitable junction depth (drive-in process). The annealing process is, however, not perfect and depending upon annealing temperature and time, interstitial dislocation loops and other unresolvable defects are left behind at the end of the annealing process. The formation of defects is also critically dependent upon the processing variables, namely, the rate of heating to the annealing temperature and the previous thermal history of the sample. Using channelling experiments, Csepregi et.al.
Progress in Single Atom Microscopy
Authors: Isaacson M. , Kopf D. , Utlaut M.
Published: June 2020

We have indicated in previous publications that a scanning transmission electron microscope (STEM) capable of atomic resolution may be a useful instrument for surface science studies and, in particular, capable of reliably observing the distribution and diffusion of individual atoms on thin film substrates (1-3). In this paper we will present further observations relating to the characteristics of individual heavy atoms on low atomic number substrates.

In figure 1, we show pair spacing distributions of individual uranium (1A) and silver (IB) atoms adsorbed to thin (˜20 Å thick) carbon film substrates. These distributions are obtained by measuring spacings between all pairs of atoms on many different fields of view (2). The two distributions for each atom type are for different specimens.(The spacing distribution is defined as the number of atoms/Å2 in an annulus of 1 Å width at a given distance from any atom.) For both the U and Ag distributions, there is a pronounced peak near 4-5 Å.
X-Ray Replication of Submicrometer Linewidth Patterns
Authors: Smith Henry I. , Flanders D.C.
Published: June 2020

Scanning electron beam lithography has been used for a number of years to write submicrometer linewidth patterns in radiation sensitive films (resist films) on substrates. On semi-infinite substrates, electron backscattering severely limits the exposure latitude and control of cross-sectional profile for patterns having fundamental spatial frequencies below about 4000 Å(l),Recently, STEM'S have been used to write patterns with linewidths below 100 Å. To avoid the detrimental effects of electron backscattering however, the substrates had to be carbon foils about 100 Å thick (2,3). X-ray lithography using the very soft radiation in the range 10 - 50 Å avoids the problem of backscattering and thus permits one to replicate on semi-infinite substrates patterns with linewidths of the order of 1000 Å and less, and in addition provides means for controlling cross-sectional profiles. X-radiation in the range 4-10 Å on the other hand is appropriate for replicating patterns in the linewidth range above about 3000 Å, and thus is most appropriate for microelectronic applications (4 - 6).
Scanning Transmission Electron Microscopy Of Polymer Single Crystals
Authors: Krause S. J. , Allard L. F. , Bigelow W. C.
Published: June 2020

Scanning transmission electron microscopy (STEM) has several advantages over conventional transmission electron microscopy (CTEM) for studying the structure of polymer single crystals. A major limitation in the electron microscopy of polymer single crystals is the rapid loss of diffraction contrast due to destruction of crystallinity by beam-induced cross-linking and/or chain scission. Electronic signal amplification, which is inherent in the STEM image forming system, allows images to be formed at lower incident beam dosages than required for photographic recording in the CTEM. This lowers the beam damage rate and routinely permits recording of bright field, dark field, and electron diffraction sequences, or alternatively, single images at high magnification for high resolution.

An SEM operated in the STEM mode at voltages in the range from 20 to 50 KV will give good images of single crystals at magnifications up to 10,000X. An STEM operated at 100 KV with cold stage techniques further improves the imaging capabilities, since beam damage is reduced by 5 to 10 times with an increase in accelerating voltage and lower sample temperatures.1
Progress In The Practical Application Of Automated Image Analysis To Tem Negatives
Authors: Heckman F. A. , Redman E. , Connolly J.E.
Published: June 2020

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.

Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:

Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.
Automated Image Analysis Of Nuclear And Cytoplasmic Changes In Exfoliated Cells From Tracheas Treated With Carcinogen
Authors: Stinson S.F. , Lilga J.C. , Sporn M.B.
Published: June 2020

Increased nuclear size, resulting in an increase in the relative proportion of nuclear to cytoplasmic sizes, is an important morphologic criterion for the evaluation of neoplastic and pre-neoplastic cells. This paper describes investigations into the suitability of automated image analysis for quantitating changes in nuclear and cytoplasmic cross-sectional areas in exfoliated cells from tracheas treated with carcinogen.

Neoplastic and pre-neoplastic lesions were induced in the tracheas of Syrian hamsters with the carcinogen N-methyl-N-nitrosourea. Cytology samples were collected intra-tracheally with a specially designed catheter (1) and stained by a modified Papanicolaou technique. Three cytology specimens were selected from animals with normal tracheas, 3 from animals with dysplastic changes, and 3 from animals with epidermoid carcinoma. One hundred randomly selected cells on each slide were analyzed with a Bausch and Lomb Pattern Analysis System automated image analyzer.
Effect of Grain Boundary Ledges on the Flow Stress in Nickel
Authors: Venkatesh Eswarahalli S. , Murr L.E.
Published: June 2020

In a recent paper1 it was shown that grain boundary ledge structure can be changed by appropriate thermomechanical treatments. Grain boundary ledges are sources of dislocations2. Recently the effects of grain boundaries on the mechanical properties in metals and alloys were studied3,4. For a few years now the structure and properties of grain boundaries and their control have been considered as a means of strengthening polycrystalline materials5,6. Li5 has derived a Hall-Petch type relation in terms of grain boundary dislocation source (ledge) density, m, in the form where L is the grain size, σ0 and α are constants, and G ana b have the usual meaning. The influence of grain boundary ledge density, on the flow stress is considered in this paper.

In the present work, pure (99.98%) nickel sheet mill rolled (hot) to 0.022 in. thick was used.
Scanning Electron Microscopy Studies of Volatile Transport within Particles During Knudsen Effusion Experiments
Authors: Schiffman R.A.
Published: June 2020

During Knudsen effusion experiments on the nickel-rich, 2-phase region of the Ni-S system (Ni3S2+Ni) it was observed that the rate of effusion was not constant as expected but diminished with time. Investigation with a Hitachi Perkin-Elmer HHS-2R SEM, fitted with an Ortec energy dispersive X-ray analyzer, presented evidence that the falloff in vaporization rate was not due to diffusion, but the change in rate can be expected from the limitations inherent in the Knudsen experimental system.

The starting material for these Knudsen effusion experiments, finely mixed NiS2 and sulfur, was placed in an effusion cell and heated at a constant temperature where sulfur, the more volatile component, effused. A mass spectrometer showed that S2 was the only effusing species over the entire Ni-S system within the 250-1100°C range investigated, as predicted.
Influence of X-Ray Induced Fluorescence on Energy Dispersive X-Ray Analysis of Thin Foils
Authors: Kenik E. A. , Bentley J.
Published: June 2020

Cliff and Lorimer (1) have proposed a simple approach to thin foil x-ray analy sis based on the ratio of x-ray peak intensities. However, there are several experimental pitfalls which must be recognized in obtaining the desired x-ray intensities. Undesirable x-ray induced fluorescence of the specimen can result from various mechanisms and leads to x-ray intensities not characteristic of electron excitation and further results in incorrect intensity ratios.

In measuring the x-ray intensity ratio for NiAl as a function of foil thickness, Zaluzec and Fraser (2) found the ratio was not constant for thicknesses where absorption could be neglected. They demonstrated that this effect originated from x-ray induced fluorescence by blocking the beam with lead foil. The primary x-rays arise in the illumination system and result in varying intensity ratios and a finite x-ray spectrum even when the specimen is not intercepting the electron beam, an ‘in-hole’ spectrum. We have developed a second technique for detecting x-ray induced fluorescence based on the magnitude of the ‘in-hole’ spectrum with different filament emission currents and condenser apertures.
Silicic Acid Analogs Affect Silica Body Assembly and Cell Wall Deposition Mechanisms in Urtica Pillulifera Stinging Cells
Authors: Sowers Arthur E.
Published: June 2020

All living organisms possess structures which are the result of macromolecular assembly processes. The mechanism and regulation of these processes is of fundamental importance and has a bearing on the structure and function problem. In the present research effort the phenomenon of silicification in the plant cell wall was the model assembly process. The silica rich cell wall of theUrtica pillulifera(common name: stinging nettle) stinging cell (shown in schematic form in Fig. 1) was the model system which displayed the phenomenon being studied. The silica is present in the form of electron- dense bodies with roughly spherical shapes. Based on morphology, the silica bodies fall into two classes: (1) primary silica bodies (Figs. 2,3) which have a narrow diameter distribution ( ave. = 50 nm ) and a compact and relatively lew electron density, and (2) secondary silica bodies (Fig. 4).
The Fine Structure of the Sheath of Volvox Carteri f. Weismannia
Authors: Birchem Regina
Published: June 2020

Spheroids of the green colonial algaVolvoxconsist of biflagellate Chlamydomonad-like cells embedded in a transparent sheath. The sheath, important as a substance through which metabolic materials, light, and the sexual inducer must pass to and from the cells, has been shown to have an ordered structure (1,2). It is composed of both protein and carbohydrate (3); studies ofV.rousseletiiindicate an outside layer of sulfated polysaccharides (4).

Ultrastructural studies of the sheath material in developmental stages ofV.carterif.weismanniawere undertaken employing variations in the standard fixation procedure, ruthenium red, diaminobenzidine, and high voltage electron microscopy. Sheath formation begins after the completion of cell division and inversion of the daughter spheroids. Golgi, rough ER, and plasma membrane are actively involved in phases of sheath synthesis (Fig. 1). Six layers of ultrastructurally differentiated sheath material have been identified.
Elementary Quantitative Analysis of Lyophilized 10-10L Volume Solutions
Authors: Roinel N.
Published: June 2020

In the biology field an analytical problem is often raised by the very small volumes available for guantitative analysis. The usual chemical technigues can be adapted to the nanoliter scale but are specific for only one or two elements. In 1967, Ingram and Hogben (1) proposed using the electron microprobe to determine potassium and chlorine concentrations in 1 nl(10-91) samples air-dried on a quartz slide. In 1969 Morel and Roinel (2) described a freeze-drying lyophilization technique which avoids X-ray and electron absorption by producing tiny micron-size crystals. This allows measurement in tenth of a nanoliter volumes of 1 mM/1 concentrations of elements of biological interest, particularly Na, Cl, K, Ca, P, Mg and Fe. The samples (unknown and standard solutions) were deposited on a beryllium holder, quickly frozen and lyophilized. This method was applied to renal physiology by Morel et al. in 1969 (3).
Immunoferritin Labelling of Intracellular Murine Mammary Tumor Virus After Thin Sectioning for Electron Microscopy
Authors: Weigand R.A. , Russo J.
Published: June 2020

Simultaneous observation of viral particles and demonstration that they contain viral antigens has only recently been achieved. Most studies involve immunocytochemical labelling followed by embedding and thin sectioning and are limited to the study of budding particles at the cell surface (1). Most recently, methods for immunocytochemical labelling after thin sectioning have been developed. Hamilton (2) has applied these methods to detect murine mammary tumor virus (MuMTV) antigens in thin sections. The method used, however, does not allow simultaneous observation of viral ultrastructure and detection of the labelling product. Here we demonstrate the intracellular localization of a MuMTV antigen. Both the viral morphology and the immuno-ferritin label (labelled MuMTV antigen) can be observed simultaneously.

Primary cultures obtained from a spontaneous mammary tumor of a C3H mouse were grown to confluency. The cultures were fixed as monolayers with cacodylate buffered 3l paraformaldehyde containing 0.05% glutaraldehyde. After dehydration, the monolayers were collected and embedded in Epon-Araldite.
Studies on Type B Virus Particles in Normal Prostate Tissues of Mice from High Mammary Cancer Strains
Authors: Ohtsuki Y. , Dmochowski L. , Seman G. , Bowen J. M.
Published: June 2020

Normal prostate tissues of mice from ten different strains were examined by electron microscopy, in order to determine the presence of virus particles and also to ascertain whether prostatic glands were a potential source of infective oncornaviruses in mice. The observation of type B virus particles in normal prostate tissues of mice has already been reported. Our studies have been presently extended to a total of 61 mice. Type B virus particles (Fig. 1) and budding (Fig. 2) have been found in prostate tissues of 8 approximately 1 year old mice from all three high (C3H/Dm, RIII/Dm and A/Dm) and of one low (BALB/c/Dm) mammary cancer strain.

Experiments have been carried out to characterize immunologically type B virus particles observed in the normal prostate tissues of mice of high mammary cancer strains. Frozen sections of prostate tissues from each of three 1 year old C3H/Dm and A/Dm strain mice were tested by fixed immunofluorescence (FIF) and by immunoelectron microscopy, using goat antiserum to mammary tumor virus (MTV) from A/Dm strain mouse milk.
Initial Polymerization Sites Indicated During Mitochondrial Oxidation of Diaminobenzidine after Toluene Treatment
Authors: Shannon W. A. , Matlib M. A.
Published: June 2020

Numerous studies have dealt with the cytochemical localization of cytochrome oxidase via cytochrome c. More recent studies have dealt with indicating initial foci of this reaction by altering incubation pH (1) or postosmication procedure (2,3). The following study is an attempt to locate such foci by altering membrane permeability. It is thought that such alterations within the limits of maintaining morphological integrity of the membranes will ease the entry of exogenous substrates resulting in a much quicker oxidation and subsequently a more precise definition of the oxidative reaction.

The diaminobenzidine (DAB) method of Seligman et al. (4) was used. Minced pieces of rat liver were incubated for 1 hr following toluene treatment (5,6). Experimental variations consisted of incubating fixed or unfixed tissues treated with toluene and unfixed tissues treated with toluene and subsequently fixed.
Morphological Characteristics of Mitochondria and Cultured Cells Made Permeable for Enzyme Studies
Authors: Shannog W. A. , Matlib M. A. , Robinson J. B. , Hochli M. , Srere P. A.
Published: June 2020

Toluene has been used to make various cells permeable to exogenous substrates. More recently we have extended the method to heart and liver mitochondria (1,2). We reduced the toluene concentration and included 8.5% polyethylene glycol (PEG) to stabilize these organelles (1).

In this study, liver and heart isolated mitochondria and hepatoma type cells (HTC cells) in PEG were treated with either 2% or 0.1% toluene, respectively. The HTC cells were in a solution of 10% PEG, the optimal concentration indicated by biochemical data. The mitochondria were fixed in suspension in 3% glutaraldehyde in 0.1 M phosphate buffer (pH 7.3). It was necessary to add 50% gl utaral dehyde to the HTC cells in PEG-buffer to give a final 3% concentration in order to prevent gross morphological degradation determined to be a result of aqueous glutaraldehyde fixation. Following treatment, specimens were post-fixed in 1% OsO4 and prepared for electron microscopy (1,2).
Ultrastructural Localization of Glycolytic Dehydrogenases in Regressing Cells and in Reticuloendothelial and other Phagocytic Cells
Authors: Hanker J.S. , Coleman R.A. , Carson K.A. , Silverman M.S. , Tyan M.L. , Romanovicz D.K. , Ambrose W.A. , Gonzales L.F.
Published: June 2020

A number of different cells of the reticuloendothelial system which are responsible for the inflammatory reaction and tissue injury, and other phagocytic or regressing cells, were studied with histocytochemical methods1,2for the direct demonstration of the glycolytic dehydrogenases (Fig. 1). The enzymes lactate dehydrogenase (LDH) and NADH dehydrogenase (diaphorase, NADH- DH) were found to be present in unusually high amounts in these cells. LDH was found associated with the limiting membranes (Fig. 2) of many vesicles, lysosomes and digestive vacuoles. It was also found, as was NADH-DH, associated with the plasmalemma and rarely with mitochondrial membranes in many of these cell types. The NADH-DH was more usually distributed in the cytoplasm of these cells than on the limiting membranes of the vacuoles, vesicles and lysosomes but was also prominent in the plasmalemma and occasionally in mitochondria. These associations of the enzymes were especially prominent in cells involved in intracellular (autophagic and heterophagic) and extracellular digestive processes.
Morphology, Histochemistry and Staining of Glycogen in the Dog Heart
Authors: Rybicka Krystyna
Published: June 2020

Muscle glycogen appears in the form of single beta-granules which become visible after staining with lead. Treatment of tissue with uranyl acetate before dehydration (en bloc) causes an apparent disappearance of glycogen. However, histochemical studies have shown that at least a part of glycogen remains in the tissue (5). In our work on the conducting tissue in the dog heart various degrees of glycogen disappearance were observed after uranyl acetate treatment of the tissue (3). The present report includes ultrahisto- chemical analysis of those samples that showed a high degree of glycogen disappearance and a tentative explanation of the effects of uranyl acetate on glycogen structure and staining.

Dog heart was fixed by perfusioninvivo with 3% glutaraldehyde in 0.1 M phosphate buffer, pH 7.2. Excised conducting fibers were fixed overnight in 6% glutaraldehyde, post fixed in OsO4, for 15 minutes, processed either routinely or with uranyl acetate, and embedded in Spurr's epoxy resin.
Analysis of Collagen Fibril Diameters from Rabbit Corneal Wounds
Authors: Cintron C. , Hassinger L.C. , Kublin C.L.
Published: June 2020

The vertebrate cornea is an avascular, translucent organ composed of an orderly arrangement of tissues in three basically parallel layers: the
epithelium, stroma, and endothelium. The stroma, or substantia propia, is an avascular connective tissue containing a sparse population of cells and a tight interlacing meshwork of extracellular fibers. In the rabbit, the deep layers of the stroma contain sharply defined ribbons of fibers (lamellae) which interweave and cross each other at many different angles parallel to the surface of the cornea. The fibers are composed of numerous fibrils which travel in the same direction within the given fiber. These fibrils are made of collagen intimately associated with an apparently amorphous matrix.

Current theory of corneal transparency suggests that restrictions in the cross-sectional diameter of collagen fibrils and the size of interfibrillar spaces are the main factors in maintaining corneal clarity. Corneal transparency is, therefore, determined in part by the physical and chemical nature of collagen in the organ.
Comparative Observations on Fatty Liver using Secondary and Back- Scattered Electrons
Authors: Nopanitaya Waykin , Grisham Joe W.
Published: June 2020

The secondary electron (SE) mode in SEM is routinely used by biologists for the purpose of studying the surface features of biological specimens. This operational mode provides an image of cell and tissue components with greater depth of focus and higher resolution than that achieved by light microscopy. The SE mode of imaging, however, does not provide an insight into intracellular substructures and components of cells.

With the advent of the modern SEM equipped with a back-scattered electron (BSE) detector, which is available in most current models, it is possible to detect intracellular fine structure in biological samples using the BSE imaging system. The present investigation is an attempt to demonstrate the usefulness of BSE imaging for detecting intracellular lipid droplets during accumulation in the liver and to compare these results with data obtained from the SE imaging system.
Effect of Calcitonin and Hydrocortisone on Skin Tumorigenesis in Mice
Authors: Lupulescu A. , Rogers J. , Herbert M. , Habowsky J. , Birmingham D.
Published: June 2020

Skin tumorigenesis is a good experimental model for the study of cell division and differentiation. Previous reports using light microscopy showed that some hormones (hydrocortisone and epinephrine) can influence the DNA synthesis in the squamous epithelial cells. (1). Also, light and electron microscopic observations revealed that calcitonin and corticosteroids significantly intervene in collagen synthesis and fibroblast growth in wounded rabbit and rats on experimental carcinogenesis induced by topical application of 3-methylcholanthrene in mice.

Adult Swiss mice were used in these experiments. They were divided in four groups of 6 mice each; A) Mice painted on dorsal skin with a 0.4% acetone solution of 3-methylcholanthrene (MCA), twice weekly for 2 months. B) Mice painted with MCA as above and concomitantly treated with salmon calcitonin (Calcimar), a dose of 5 MRCU (Medical Research Council Units) injected intramuscularly (im) twice weekly for 2 months. C) Mice painted with MCA and injected (im) with hydrocortisone acetate (Cortef) 2.5 mg.
Ultrastructural Features of a Poorly Differentiated Neoplasm Resembling Synovial Sarcoma
Authors: Simons P. K.
Published: June 2020

Synovial sarcoma is a malignant mesenchymal tumor most commonly occurring in the extremities, but is occasionally seen in the trunk, head, and neck regions. The well developed lesion exhibits a distinct biphasic histologic morphology consisting of a spindle cell fibrosarcomatous stroma and epithelial-lined pseudoacinar structures with an associated mucopolysaccharide secretion. The presence of this biphasic pattern is dependent upon the degree of histologic differentiation. Few studies of the fine structure of synovial sarcomas are available and none of the literature has been concerned with these neoplasms occurring in the less common areas. The ultrastructural features of a tumor classified as a poorly differentiated synovial sarcoma are presented.

A mass of irregularly shaped, cerebreform tissue was surgically removed from the left side of the neck of a 61 year old white male. The majority of the tissue was fixed in neutral buffered formalin and prepared for light microscopy.
Studies on the Reversible Effects of Concanavalin A on CHO Cells in Culture
Authors: McCarty Kenneth S. , Wallace N.R. , Kaufman B. , McCarty K.S.
Published: June 2020

Plant lectins have been useful probes to test the concept that the plasma membrane plays an important role in the regulation of mitotic activity. The carbohydrate specificity of the proteins provides a means of identification of the residues available to the external environment of the cell surface as well as a capacity for the rapid reversal of its effect.

As part of a series of studies on the post-synthetic modifications of chromosomal proteins during mitosis, we tested the effect of the lectin Concanaval- in A (ConA) on Chinese hamster ovary (CHO) cells (clone, K1, Pro-). The generation time for untreated cells was 11.9 hrs. Preliminary observations demonstrate that 30 μg/ml of ConA inhibits the cell cycle at a stage immediately prior to mitosis. The ConA treated cells assume a spherical configuration, which is maximal at the end of 10-11 hrs, with thymidine uptake evident at 4 hrs but not at 10 hrs.
Re-Embedding of Tissue Culture Cells for Comparative and Quantitative Electron Microscopy
Authors: Connelly P. S.
Published: June 2020

Three common methods of preparing tissue culture cells for examination by TEM, i.e. harvesting and pelleting, face-on sectioning and cross-sectioning have inherent limitations if the cells are to be used in a comparative and quantitative study. The large number of cells per section in the harvesting method is overshadowed by the total loss of initial orientation of the cells, changes in organelle position and damage to a number of the cells due to the disruptive methods utilized in the harvesting. Face-on sectioning, which is ideal for the examination of preselected individual cells has the limitation in a comparative study of varying section thicknesses and possible staining differences. These limitations also apply to crosssections and two additional factors add to the reasons why this method is usually rejected. First, unless the cell monolayer is confluent, there will be relatively few cells in a section and second, these sections cannot be examined on unsupported grids because the cells are on the edge of the section.
Intercellular Junctions in Fanft-Induced Transitional Cell Carcinomas in Tissue Culture, In situ Freeze-Fracture Studies
Authors: Pauli Bendicht U. , Weinstein Ronald S.
Published: June 2020

Junctional abnormalities have been described in electron microscopy studies of a broad spectrum of human and animal tumors (for review, see Ref. 1). In such studies, quantitative and qualitative descriptions have been related to tumor morphology and, occasionally, to tumor biological behavior. Few investigations have attempted to correlate changes in junction ultrastructure with dynamic aspects of malignant transformation since such studies would be difficult to carry out in solid tissues. Further, until recently, methods available for freeze-fracturing tissue cultures were cumbersome and limited in their applications.

In this study, we have examined the ultrastructure of cell junctions in tissue culture lines derived from chemical carcinogen induced epithelial tumors, using a novel freeze-fracture technique. The ultrastructure of the cultures was contrasted with comparable solid tumors, as described elsewhere (2). We examined four cell lines in continuous culture (AY27, AY32, AY33, AY34), which we grew from FANFT-induced Fischer rat urinary bladder carcinomas (3), and a fifth line derived from subcutaneously transplanted rat bladder carcinoma (CN27T).
Freeze-Fracture Study of Microfilament Attachments to Membranes
Authors: McNutt N. Scott
Published: June 2020

Actin-containing microfilaments are part of contractile systems in many cells, and the functions of these systems require some type of attachment of microfilaments to membranes (1). This attachment is particularly necessary at the fascia adherens in the intercalated disc of cardiac muscle (2) and at the tips of intestinal microvilli (1). At these locations, the actin filaments are perpendicular to the membrane and a dense-filamentous material is present at the sites of attachment. Freeze-fracture studies of these membranes have revealed a decrease in P face particle density at the fascia adherens (2) and at the tips of intestinal microvilli (3). In contrast, when the microfilaments lie parallel to the plane of the membrane, another structural type of attachment is found which is mediated by fine cross-bridges instead of the dense filamentous material. These cross-bridges are visible in both thin-section and freeze-etch preparations (1,4). The freeze-fracture counterpart of this type of cross-bridge attachment has not been shown previously.
Fine Structure of Spermatogenesis in the Snail Tarebia Granifera (Melaniidae)
Authors: Scates Ronald W. , Blystone Robert V.
Published: June 2020

Jacob (1), citing chromosomal studies, emphasized the extreme rarity, or possible non-existence of viable males in observed Indian populations of Melanoides tuberculatus, of the same family as Tarebia granifera. The snail population, almost totally female in chromosomal count, were presumed to reproduce parthenogenetically; no sexual reproduction was in evidence (no sperm were ever reported observed). Similar findings were reported by Pace (2) in his comprehensive study of populations of T. granifera on the island of Taiwan. Pace, correlating his own findings with those of Jacob, suggested that T. granifera reproduce by apomictic parthenogenesis.

A population of T. granifera is found in Brackenridge Park, San Antonio, Texas. The reproductive tract of randomly selected snails was prepared for electron microscopy. The tissue was fixed in 3% glutaraldehyde in 0.1 M sodium phosphate buffer, postfixed in buffered 1% Osmium tetroxide, dehydrated, and embedded in Spurr embedding media.
The Armadillo Median Eminence: Correlative Scanning + Transmission Electron Microscopy and Cytochemistry
Authors: Ives Phillip J.
Published: June 2020

The cerebral ventricular system, including the ependymal cells of the median eminence, is postulated to be an important site of neuroendocrine transport and control1. The median eminence helps to transfer activity between the hypothalamus and adenohypophyseal control centers. The ependymal lining of the 3rd ventricle contains many different cell types active in phagocytic or autoregulato^y mechanisms involving the transport of releasing hormone or biogenic amines2. Understanding the primitive mammalian ventricular system is essential in determining significance and comparison of structure, development and organization in the more advanced mammalian species. The present investigation was designed to study the organization of the armadillo median eminence and allow for comparison with other animal systems.

The median eminence was removed from each of four immature and eight adult male and female armadillos and processed using standard EM techniques. Some samples were scanned and then placed in 100% acetone and processed for correlative TEM.
Cerebral Response to Ischemia Induced by the Embolism Model
Authors: Dodson R.F. , Chu L. W-F , Miyakawa Y.
Published: June 2020

Two of the most reproducible animal models used to study cerebrovascular related changes involve the surgical occlusion of cerebral vessels or introduction of an embolic material into the cerebrovascular system. The present paper reports the ultrastructural evaluation of parenchymal and arterial response following embolization as compared with those changes induced by vascular clipping.

Six adult baboons (papio anubis) were anesthetized and after surgical preparations for physiological monitoring were completed the embolus was injected through the left carotid catheter in accordance with the Molinari procedure (1) for selective segmental occlusion of the stem of the middle cerebral artery. After an interval of two hours during which continuous monitoring was carried out, the animals were prepared for ultrastructural evaluation by being subjected to whole body intracardiac perfusion. Specimens were taken from the frontal, parietal, occipital, and insular cortices, putamen globus pallidus, caudate nucleus as well as the areas of the artery, proximal, under and distal to the embolus.
Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)
Authors: Dailey P.J.
Published: June 2020

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).

Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.

Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.
Morphological Characteristics of the Abdominal Paraganglia (Extraadrenal
Chromaffin Tissue) in the Rhesus Monkey
Authors: Mascorro J.A. , Klara P.M. , Yates R.D.
Published: June 2020

The abdominal paraganglia represent extraadrenal chromaffin organs rich in catecholamines. Earlier work indicated that the organs degenerate soon after birth. More recently, however, investigators have reported the distribution and persistence of this extraadrenal chromaffin system in higher mammals, including man . The present work reports the occurrence of paraganglia in Rhesus monkeys and illustrates their ultrastruotural morphology.

Two young adult Rhesus monkeys weighting approximately 6 kg. were anesthetized with Nembutal and perfused routinely with glutaraldehyde/ paraformaldehyde in 0.1M sodium cacodylate buffer. The paraganglia were stained and localized by immersing the retroperitoneal tissue block in glutaraldehyde/potassium diahromate and subsequently processed for electron microscopy via rapid dehydration and embedding.

Potassium dichromate tracing produced a gross chromaffin reaction that initially identified the paraganglia as catecholamine containing organs. Correlative electron microscopic observations revealed that the organs were characterized by groups of cells whose cytoplasm contained conspicuous and voluminous accumulations of dense granules.
Serum-Induced Endocytic Vacuole in the Nonphagocytic Tetrahymena Pyriformis Strain NP1
Authors: Brenner L. J. , Osborne D. G. , Schumaker B. L.
Published: June 2020

Tetrahymena pyriformis strains WH6, W, HSM, and GLC, after exposure to normal human serum, give rise to large membrane-bounded endocytic vacuoles, as visualized by transmission electron microscopy (TEM). These vacuoles do not resemble ordinary food vacuoles formed in the oral apparatus. Nor do they appear to be vacuoles containing protein concentrated from the serum: Albumin solutions induce a different type of vacuole (Brenner et al., 1976). The large bodies take a stain (PAS) that indicates the presence of polysaccharide. TEM micrographs show the presence of lipid in some of the large bodies. It is not yet known if these large body vacuoles are formed in the oral apparatus like food vacuoles or result from the fusion of pinocytic vacuoles.

Although the mutant T. pyriformis strain, NP1, is unable to form a functional oral apparatus at 37° C and cannot form food vacuoles (Rasmussen and Orias, 1975), it multiplies in 2% proteose peptone medium supplemented with vitamins and heavy metal salts.