bluuebunny/crossref_metadata_2025 huggingface dataset:
A High Voltage Electron Microscopy Study of Sub-Oxide Formation in Vanadium
Authors: Geiss R. H. , Ladd R. L. , Lawless K. R.
Published: June 2020

Detailed electron microscope and diffraction studies of the sub-oxides of vanadium have been reported by Cambini and co-workers, and an oxidation study, possibly complicated by carbon and/or nitrogen, has been published by Edington and Smallman. The results reported by these different authors are not in good agreement. For this study, high purity polycrystalline vanadium samples were electrochemically thinned in a dual jet polisher using a solution of 20% H2SO4, 80% CH3OH, and then oxidized in an ion-pumped ultra-high vacuum reactor system using spectroscopically pure oxygen. Samples were oxidized at 350°C and 100μ oxygen pressure for periods of 30,60,90 and 160 minutes. Since our primary interest is in the mechanism of the low pressure oxidation process, the oxidized samples were cooled rapidly and not homogenized. The specimens were then examined in the HVEM at voltages up to 500 kV, the higher voltages being necessary to examine thick sections for which the oxidation behavior was more characteristic of the bulk.
Electron Microscopy of Thin Film Immiscible-Miscible Systems
Authors: Staudhammer K. P. , Murr L. E.
Published: June 2020

Some preliminary studies on immiscible systems have been previously reported. This paper is a continuation of this work in an effort to expand the characterization of immiscible systems. The non-equilibrium behavior of many thin film materials compared to that of the bulk is fairly well established. The work discussed in the present paper is a comparative investigation of immiscible systems such as Ni-Ag to that of a simple eutectic, Ag-Si. Earlier work on immiscible systems has shown that upon thermal activation, one of the components exsolves out of the matrix and grows as single crystals upon the thin film matrix. Further investigation revealed this to be characteristic of a number of immiscible systems; however, a few anomalies have been found.

Thin films were prepared by the co-evaporation of the components from separate sources at ambient temperatures onto freshly-cleaved (100) NaCl substrates. The co-evaporated films (300-400 Å thick) were deposited at a nominal background pressure (prior to deposition) of 4 X 10-5torr.
Aspirin-Induced Damage to the Gastric Mucosa
Authors: Pfeiffer C. J. , Weibel J. , Bair J. W. , Roth J. L. A.
Published: June 2020

The gastric bleeding diathesis related to ingestion of salicylate compounds has long been recognized. Although the pathogenesis of this common adverse drug reaction is poorly understood, hypotheses have been advanced suggesting the direct irritation of the mucosa by salicylate, impaired mucus protection of the gut surface, back diffusion of hydrogen ions, and adverse systemic effects of salicylate on the mucosal metabolism. The present study was undertaken to characterize the early cytologic responses, the relative sensitivities of different mucosal cell types, and the mucosal surface damage related to bleeding after oral ingestion of aspirin.

Acetylsalicylic acid (10 mg/kg) in an acidic solution (0.1 N HCl) was administered by gastric intubation to normal adult female ferrets, and animals were sacrificed at 10-45 min after ingestion. Control ferrets received 0.9% NaCl, 0.1 N HC1, or a solution containing both aspirin and sodium bicarbonate buffer (10 mEq/kg). Tissue samples taken from both the antrum and fundus of the stomach, were prepared in a conventional manner and studied with a Jeolco Jem-7 Transmission Electron Microscope.
A New Cell-Type in the Impulse-Conducting Tissue of Rat Heart
Authors: Sekhri K. K.
Published: June 2020

The ultrastructural alterations induced in the contractile cardiac tissue of rats by chronic administration of alcohol have been reported previously. The present paper deals with the cardiotoxic effects of ethanol on the impulse-conducting tissue. Several groups of male simonsen rats were fed commercial Purina rat chow diet and 15% ethanol ad libitum for 55 weeks. The controls were maintained on chow diet and distilled water. For electron microscopy tissue samples from atrium were fixed in 2.5% Cacodylate-buffered Glutaraldehyde, post-fixed in 2% buffered Osmium tetroxide and embedded in Epon-Araldite.

On EM examination, the myocardial cells of alcoholic rat showed profound ultrastrcutural changes involving the formation of giant mitochondria by a process of coalescence, coupled with the fragmentation of myofibrils and the dehiscence of the intercalated discs. The conduction tissue of the treated animals, however, revealed an unusual type of cell, which to my knowledge has not been reported before in the literature. This peculiar conduction cell was wedged in between the ordinary myocardial cells and was characterized by a few remnants of sarcomeres delimited by dark Z lines and the familiar thick and thin filaments. The glycogen granules were scanty and the few mitochondria were randomly scattered.
Congenital Dyserythropoietic Anemia Type II: Excessive Endoplasmic Reticulum in Erythroid Cells and Mitochondrial Inclusions of Hepatic Cells
Authors: Hug George , Wong K. Y. , Lampkin Beatrice
Published: June 2020

Congenital dyserythropoietic anemia (CDA) as described in 1966 was characterized by (i) erythroblastic multinuclearity and (ii) lysis of the patient's red cells in acidified compatible normal human serum. This condition has since been labeled CDA Type II to distinguish it from a similar entity, CDA Type I, with erythroblastic multinuclearity but without red cell lysis in acidified human serum. According to this classification, our initial study of bone marrow ultrastructure in CDA concerned a girl with Type II. Her bone marrow contained erythroid cells with excessive cytoplasmic membranes and multiple nuclei. The present report illustrates this observation. The patient was a 12 year old white girl with congenital anemia and benign recurrent jaundice. Hemolysis was not present since Cr51 red cell survival time was normal. Bone marrow aspirates (Figure 1, 2 and 4) circulating red cells (Figure 3) and hepatic biopsy specimens were examined. The markers indicate 0.5 microns and N designates nucleus. The myeloid series was normal. Figure 1 shows a representative polychromatophilic normoblast.
Ultrastructural Pathology of Syphilitic Interstitial Keratitis
Authors: Van Horn Diane L. , Pederson Harlan J.
Published: June 2020

Gradual loss of corneal transparency and resultant reduction of visual acuity may be a late manifestation of congenital syphilis. These changes may occur years after the acute attack of syphilitic interstitial keratitis which leaves “ghost vessels” in the deep layers of the stroma as permanent proof of the previous attack. In this study, six corneal buttons obtained at the time of transplantation surgery in five adult patients with congenital syphilis were examined by light and electron microscopy.
Adenomatoid Tumor of the Testis, A Mesonephric Hamartoma
Authors: Fresco Raoul , Chang-Lo Mary
Published: June 2020

Confusion surrounds the nature of the “adenomatoid tumor” of the testis, as evidenced by the large number of synonyms which have been ascribed to it. Various authors have considered the tumor to be of endothelial, mesothelial or epithelial origin. There appears to be no controversy as to the stromal elements of the tumor, which consists mainly of smooth muscle and fibrous tissue. It is the irregular gland-like spaces which have given rise to the numerous theories as to its histogenesis, and even recent ultrastructural studies fail to agree on the origin of these structures.

Electron microscopy of a typical intrascrotal adenomatoid tumor showed the gland-like spaces to be lined by epithelial cells (Fig. 1), rich in cytoplasmic tonofibrils and united to each other by numerous desmosomes (Fig. 2). The most salient feature of these epithelial cells was the presence on their luminal surface of numerous long and repeatedly branching microvillous structures of the type known as stereocilia (Fig. 3). These are extremely long slender cell processes which are as much as three to four times the length of those in brush borders.
Cell Wall Ultrastructure in Three Strains of a Cariogenic Streptococcus
Authors: Kramer M. J. , Coykendall Alan L.
Published: June 2020

During the almost 50 years since Streptococcus mutans was first suggested as a factor in the etiology of dental caries, a multitude of studies have confirmed the cariogenic potential of this organism. Streptococci have been isolated from human and animal caries on numerous occasions and, with few exceptions, they are not typable by the Lancefield technique but are relatively homogeneous in their biochemical reactions. An analysis of the guanine-cytosine (G-C) composition of the DNA from strains K-1-R, NCTC 10449, and FA-1 by one of us (ALC) revealed significant differences and DNA-DNA reassociation experiments indicated that genetic heterogeneity existed among the three strains. The present electron microscopic study had as its objective the elucidation of any distinguishing morphological characteristics which might further characterize the respective strains.
The Ultrastructure of Luzula Kinetochores During Mitosis
Authors: Braselton James P.
Published: June 2020

In most eukaryotic organisms the attachment of each chromosome to the division spindle occurs at a specialized region, the kinetochore (centromere), which generally appears in light microscopy as a constriction. Ultrastructural descriptions of localized kinetochores may be classified into the following categories: (a) the kinetochore region appears morphologically undifferentiated from the rest of the chromatin; (b) the kinetochore appears more electron-dense than the rest of the chromatin; (c) the kinetochore appears less electron-dense than the rest of the chromatin; and (d) the kinetochore consists of several layers of varying complexity and electron-density (for reviews see 1, 3, and 6).
Ultrastructural Changes in the Epidermal Cells of the Cotyledon in the Germinating Seeds of Euphorbia esula
Authors: Fellows R. J. , Hayat M. A.
Published: June 2020

The transformation of an apparently inanimate seed into a viable, growing organism has been the object of many investigations. Several investigators have studied the ultrastructure of the seed embryo both in the dormant and in the germinating seed (e.g., Yoo, 1970). While mature leaves of the family Euphorbiaceae have been studied (Marty, 1969), no work has been reported on the embryo of the germinating seed. The objective of this study was to follow the ultrastructural changes in the epidermal cells of the cotyledon accompanying the germination of the seed.

Samples were taken from the cotyledons of both the dormant and the germinating seeds. The seeds were germinated on moistened filter paper in the dark at 20-22°C. Samples of germinating seeds were taken at 3,4,5,6,7 and 8 days after initial imbibition. All tissue samples were processed according to standard procedures (Hayat, 1970).
A SEM and Light Microscope Study of the Epidermal Leaf Structures of the Carnivorous Plant, Sarracenia purpurea, L.
Authors: Panessa B. J. , Gennaro J. F.
Published: June 2020

Tissue from the hood and sarcophagus regions were fixed in 6% glutaraldehyde in 1 M.cacodylate buffer and washed in buffer. Tissue for SEM was partially dried, attached to aluminium targets with silver conducting paint, carbon-gold coated(100-500Å), and examined in a Kent Cambridge Stereoscan S4. Tissue for the light microscope was post fixed in 1% aqueous OsO4, dehydrated in acetone (4°C), embedded in Epon 812 and sectioned at ½u on a Sorvall MT 2 ultramicrotome. Cross and longitudinal sections were cut and stained with PAS, 0.5% toluidine blue and 1% azure II-methylene blue. Measurements were made from both SEM and Light micrographs.

The tissue had two structurally distinct surfaces, an outer surface with small (225-500 µ) pubescent hairs (12/mm2), numerous stoma (77/mm2), and nectar glands(8/mm2); and an inner surface with large (784-1000 µ)stiff hairs(4/mm2), fewer stoma (46/mm2) and larger, more complex glands(16/mm2), presumably of a digestive nature.
Freeze-Etching of Intranuclear Adenovirus
Authors: Brown Dennis T. , Burlingham Byron T.
Published: June 2020

Adenoviruses are revealed by negative staining to be icosahedral in structure and composed of 252 subunits (insert Fig. 1). The vertices have a fiber-like projection which has been implicated in the adsorbtion of the virus to the host cell. Ultra thin sections of adenovirus-infected cells has revealed that virus morphogenesis occurs in the nucleus.

Human carcinoma (KB) tissue culture cells were productively infected with adenovirus type 2 at a multiplicity of 10 and incubated for 40 hours at 37°C. The infected monolayers were fixed in place with 1%, gluteraldehyde buffered in Millonigs phosphate buffer. The fixed cells were suspended in 30%, glycerol and processed according to the procedure of Moor in a Balzers 360 M freeze etch unit with an etching time of 70 seconds at -100°C. A second portion of the fixed cells in glycerol was post-fixed with 1% osmium tetroxide and embeded in epon 812 for ultrathin sectioning.
Fine Structural Analysis of Sarcoma-180 Tumor Before and After cis-Platinum (II) Diamminodichloride
Authors: Aggarwal S. K. , Sodhi A. , Van Camp L.
Published: June 2020

It has been shown that a single injection of 8.0 mg/kg of the cis (Pt(NH3)2cl2) in normal saline is effective in regressing solid Sarcoma-180 tumors in Swiss White mice, with no apparent irreversible damage to the host. Present investigations were undertaken to study the fine structure of Sarcoma-180 under experimental and control conditions. Platinum injections were made on day 10, (taking the tumor implant as day 0), and the animals were sacrificed at 2 day intervals for 12 days after the injections. The tissue from injected and uninjected animals was processed for electron microscopic studies.
Localization of Sodium in Normal and Inhibited Transporting Epithelia
Authors: Kaye G. I. , Cole J. D.
Published: June 2020

For a number of years we have used an adaptation of Komnick's KSb(OH)6-OsO4 fixation method for the localization of sodium in tissues in order to study transporting epithelia under a number of different conditions. We have shown that in actively transporting rabbit gallbladder epithelium, large quantities of NaSb(OH)6 precipitate are found in the distended intercellular compartment, while localization of precipitate is confined to the inner side of the lateral plasma membrane in inactive gallbladder epithelium. A similar pattern of distribution of precipitate has been demonstrated in human and rabbit colon in active and inactive states and in the inactive colonic epithelium of hibernating frogs.
Structure and Function of Isolated Mucosal Cells of the Urinary Bladder of Turtle (Pseudemys scripta)
Authors: Yoder M. J. , Gennaro J. F. , Linsky N. B. , Brodsky W. A. , Scott W. N.
Published: June 2020

The isolated urinary bladder of the fresh water turtle (Pseudemys scripta) actively transports sodium, chloride and bicarbonate from the luminal to the blood side of the tissue. Electron micrographs of the intact epithelium reveal several cell types. We have attempted to separate the various cell types in order to determine whether structural heterogeneity is paralled by functional heterogeneity.

Urinary bladders, were dissected from exsanguinated turtles, and rinsed with Ringer's solution. The necks of thess bladders, in the form of closed sacs, were each tied to the outlet of a Luer lock syringe, filled with and immersed in Ca++ free Ringer's solution containing 2 mM EDTA, and incubated for 60 min. at 25°C. The fluid containing the disaggregated mucosal cells was collected and centrifuged at 5,000 g for 15 min. (2X). The cells were resuspended in Ringer's solution (containing 2 mM EDTA)and layered over a Plcoll gradient. Ficoll dissolved in EDTA-Ringer's was used to prepare discontinuous gradients (5-30 % Ficoll) in a Beckman SW-27 rotor.
Electron Microscopy of EDTA-Treated Ribosomal Subunits from Escherichia coli
Authors: Nisbet John H. , Slayter Henry S.
Published: June 2020

Several studies have indicated that treatment of ribosomes and ribosomal subunits with EDTA at low ionic strength results in the formation of slower-sedimenting species which have not lost any significant amount of protein (see, for example, reference 1). Here we attempt to follow morphologically the process of magnesium removal from the 50S ribosomal subunit of Escherichia coli, using strain Q13 which exhibits a low RNase I activity. 50S particles, initially in 0.01M Tris, 0.0001M MgCl2, pH 7.4, were treated with EDTA either by dialysis against 0.002M Tris, 0.001M EDTA, pH 7.4, or by direct addition of a 0.1M solution of EDTA to a final concentration of 0.001M. On sucrose gradients made up in the Tris-EDTA buffer, the particles sedimented as a sharp peak in the 10-12S region, with no detectable slower - sedimenting species. Sucrose gradient analysis of the ribosomal RNA following EDTA treatment of 50S subunits showed that 23S RNA were largely converted to 16S, reflecting a low level of endogenous nuclease activity in the subunit preparation.
Qualitative and Quantitative Analysis of tRNA with the Electron Microscope
Authors: Yoshikami Doju , Abermann Reinhard J.
Published: June 2020

Several investigators have already performed EM studies of tRNA; however, they did not report any statistical assessment of their EM micrographs, and it appears that their preparative procedures may have been limiting in this regard. In contrast, the reproducibly uniform distributions of tRNA particles in the EM micrographs obtained by the procedures described in the accompanying paper allow us to readily identify and characterize tRNA by EM in a quantitative manner. In order to exploit this ability, we have conducted experiments wherein monomers and dimers of tRNA were examined.

We have synthesized covalently bonded dimers of tRNA where the monomeric units were linked to each otherviatheir 3′ termini. The 3′ terminal ribose moieties of two monomers were cross-linked with a dihydrazide to produce the dimer. The dimer was purified after synthesis by gel-filtration chromatography (Fig. 1). The preparatory procedure for EM visualization described in the accompanying paper gave sufficient resolution so that the dimer could be readily distinguished from the monomeric starting material (compare Fig. 2a (dimer) with Fig. 2c (monomer)).
Structures Formed by Cryoprotective Agents Used in Freezc-Etching
Authors: Cocks G. G. , Cluthe C. E.
Published: June 2020

The freeze etching technique is potentially useful for examining dilute solutions or suspensions of macromolecular materials. Quick freezing of aqueous solutions in Freon or propane at or near liquid nitrogen temperature produces relatively large ice crystals and these crystals may damage the structures to be examined. Cryoprotective agents may reduce damage to the specimem, hut their use often results in the formation of a different set of specimem artifacts.

In a study of the structure of polyethylene oxide gels glycerol and sucrose were used as cryoprotective agents. The experiments reported here show some of the structures which can appear when these cryoprotective agents are used.

Figure 1 shows a fractured surface of a frozen 25% aqueous solution of sucrose. The branches of dendritic ice crystals surrounded hy ice-sucrose eutectic can be seen. When this fractured surface is etched the ice in the dendrites sublimes giving the type of structure shown in Figure 2. The ice-sucrose eutectic etches much more slowly. It is the smooth continuous structural constituent surrounding the branches of the dendrites.
A Simple, Reliable Method for Preparing Perforated Formvar Films
Authors: Eisner Paul R.
Published: June 2020

Perforated films used as test specimens for compensation of asymmetry in electron microscope lenses can be made by introducing water or glycerol into a Formvar solution. This can be done by preparing an emulsion or by exposing a thin layer of Formvar solution on the surface of glass to steam or moist air. Consistent production of small, round test holes with smooth edges is difficult. The following method employs solvent treatment for enlarging perforations formed in high humidity. Edge characteristics and hole size can be controlled easily and consistently. Useful holes as small as 0.15μ diameter can be produced.

Procedures described by Bradley are used to clean glass slides, dissolve Formvar in ethylene dichloride, cast films on glass, and mount films on grids. In a room or chamber at room temperature (23 C) with 50-70%. relative humidity, the clean glass slides are dipped into a Coplin staining jar containing 0.2-0.4% (w/v) Formvar solution. Figure 1 shows perforations formed during casting in a chamber at 60% relative humidity using a 0.4% Formvar solution. The perforated films are mounted on grids, which are immersed in acetone, absolute methanol, or chloroform-absolute methanol (1:9) contained in compartments of a depression plate.
Fibrin Clots for Electron Microscopy and Cytochemistry of Minute Biological Samples
Authors: Sicko Linda M. , Arnold Wm. James
Published: June 2020

The inclusion of loose cells and tissue fragments in protein or agar matrices is an accepted method to facilitate handling and processing for microscopy. Means of attaining the matrix have extended from the use of chicken blood plasma to highly refined and expensive nucleohistone gels, but more often, the difficult and often unsatisfactory suspension of materials in molten agar. Fibrin clots, introduced by Chatton and Lwoff, have the advantages of availability, speed and ease of application, predictability, homogeneity of dispersal, low expense, and applicability to the embedding of a wide variety of specimens in polymers for light and electron microscopy. The fibrin clot is high among the preferred methods of manipulating fragile protistes and yeasts and mycetozoans and fungi.

Fibrin is compatible with most common buffer systems except ones containing cacodylate, as noted by Charret and Fauré-Fremiet. By manipulating fibrinogen content, clots may be prepared with densities ranging from an open, mucus-like network, just binding specimen particles together (200 mg per 100 ml), to hard agar-like gels capable of withstanding considerable rough handling (1.5 percent). With animal cell suspensions and blue-green algae we prefer a concentration of 0.7 percent bovine fibrinogen, Cohn fraction I (Nutritional Biochemicals, Cleveland) dissolved in distilled water with the salts suggested by Furtado: sodium citrate, 0.16 percent and sodium chloride, 0.85 percent. Bovine fibrinogen is least expensive but the amount of clotable material varies according to the manufacturer, thus norms may have to be adjusted when changing lots. We prefer to use freshly prepared solutions of fibrinogen. Thrombin (Parke-Davis, Detroit) is used in sterile distilled water or saline at a concentration of 100 N.I.H. units per milliliter. Thrombin may be stored frozen at least 2 months in 10x concentrated stock solution.
Band Densities in Unstained and “Negatively Stained” Collagen Fibrils
Authors: Spadaro J. A.
Published: June 2020

Three models for the 3-dimensional organization of tropocollagen macromolecules within the collagen fibril are currently in vogue. While all fairly similar, these models are largely based on, or in agreement with, electron micrographs from collagen stained with the “negative contrast” technique. The purpose of this study was to examine the banding pattern in electron micrographs of unstained collagen fibrils and compare this to the “negatively stained” pattern and to the band densities predicted by the theoretical models. The results indicate that the models need modification and that a revised interpretation of “negatively stained” micrographs of collagen is in order.
Selective Staining of Pulmonary Type II Alveolar Cell Lamellar Bodies in “I-Micron” Plastic Sections
Authors: Mackay G. R.
Published: June 2020

Schlipköter in 1954 described a concentric lamellated osmiophilic body contained within the cytoplasm of certain pulmonary alveolar epithelial cells. The occurrence of these bodies and microvilli on the free cell border is the ultrastructural trademark of the type II alveolar epithelial cell. Numerous reports have been made concerning the histogenesis of this cell type and the composition and function of its lamellated inclusions. Though the significance of these bodies remains undetermined, their faithful occurrence facilitates the identification of the type II cell in fine structure studies.

In paraffin sections of lung tissue, vacuoles are found in those cytoplasmic areas of the type II cell which are normally occupied by the lamellar inclusions. Presumably a chemical extraction has occurred during the embedding procedure. Thus, the identification of the type II cell in these sections is based mainly upon its shape and location. When 1-2 micron-thick sections of plastic-embedded lung tissue are stained with methylene blue and azure II, then counterstained with basic fuchsin according to the method of Mackay and Mead, the lamellar bodies of the type II cell show an affinity for the basic fuchsin.
Ultrastructure of Oviduct Epithelium of the Porcine in Estrus
Authors: Nayak R. K. , Zimmerman D. R.
Published: June 2020

Cyclic changes of porcine oviduct epithelium studied by light microscopy were first reported by Snyder in 1923. UltrastructuraI features of the porcine oviduct epithelium have not yet been described. Electron microscopic studies of oviduct epithelium have been reported for only a few species. These reports have been recently reviewed by Nilsson and Relnius. This report describes the fine structure of, the oviduct epithelium and attempts to elucidate the mechanism of ciliogenesis and the secretory process in the porcine during estrus.

Tissue sections from the fimbria and ampulla were fixed in cold 3% cacodylate buffered glutaraldehyde (pH 7.4), post-fixed in 1% osmic acid and embedded in Epon. Ultra-thin sections were stained with uranyl acetate and lead citrate and examined in a RCA 3-G electron microscope operated at 100 kv.

The epithelium of the tubal mucosa consists of secretory and ciliated cells. The cells are columnar and rest on a common basement membrane, which is about 50 mμ thick. The distal or free borders of the surface epithelial cells possess few irregular microvilli. The membranes of adjacent cells show tight intercellular junctions and macula adhaerentes (Figs. 1, 2).
Early Development of Drug-Induced Hepatic Necrosis
Authors: Zaki F. G. , Detzi E. , Keysser C. H.
Published: June 2020

This study represents the first in a series of investigations carried out to elucidate the mechanism(s) of early hepatocellular damage induced by drugs and other related compounds. During screening tests of CNS-active compounds in rats, it has been found that daily oral administration of one of these compounds at a dose level of 40 mg. per kg. of body weight induced diffuse massive hepatic necrosis within 7 weeks in Charles River Sprague Dawley rats of both sexes. Partial hepatectomy enhanced the development of this peculiar type of necrosis (3 weeks instead of 7) while treatment with phenobarbital prior to the administration of the drug delayed the appearance of necrosis but did not reduce its severity.

Electron microscopic studies revealed that early development of this liver injury (2 days after the administration of the drug) appeared in the form of small dark osmiophilic vesicles located around the bile canaliculi of all hepatocytes (Fig. 1). These structures differed from the regular microbodies or the pericanalicular multivesicular bodies. They first appeared regularly rounded with electron dense matrix bound with a single membrane. After one week on the drug, these vesicles appeared vacuolated and resembled autophagosomes which soon developed whorls of concentric lamellae or cisterns characteristic of lysosomes (Fig. 2). These lysosomes were found, later on, scattered all over the hepatocytes.
Image Analysis of Electron Micrographs by Computor
Authors: Watanabe M. , Sasaki S. , Anasawa N.
Published: June 2020

Since the electron microscope allows only a two-dimensional image of the specimen to be projected in the direction of the incident beam, it is difficult to represent a three-dimensional arrangement of the specimen substructure from an electron microscopic image. It is also difficult and troublesome to determine the inner specimen structure by means of electron diffraction due to its intrinsic nature. The same is ture of stereo electron microscopic technique. A new method by which one can derive detailed information on the three-dimensional structure of materials is of vital necessity.

A method of quantitative determination of three-dimensional structure from electron microscopic images has been reported by De Rosier and Klug. This method makes it possible to derive from electron micrographs, the structures of micro specimens and bio-polymers inadequate for X-ray analysis.
Ultrastructural Cytochemical Demonstration of Acid Phos Phatase in Trophozoites of E. Histolytica.
Authors: Feria-Velasco A. , Treviño N.
Published: June 2020

Although proteolytic enzymes have been found in Entamoeba histolytica, a good correlation of those findings and its invasiveness can not be properly done without taking into account some other factors; namely a) its association with pathogenous and non-pathogenous bacteria, as well as with some flagellates; and b) the presence of various enzymes within the trophozoites. Employing biochemical techniques, several enzymes have been demonstrated in homogenates of E. histolytica. However, little attention has been paid to the precise location of those enzymes -within the cytoplasm of the trophozoite. For demonstration of acid phosphatase in trophozoites of E. histolytica A.B.R.M. strain obtained from acute ulcerative amebic colitis were cultured in a monoxenic medium with Bacteroides symbiosus (12829 strain from the American Type Collection), according to the Shaffer-Frye method. Tests for pathogenicity of the parasites were positive in hamsters and Guinea pigs after inoculation in the liver and peritoneum. After separation of the trophozoites from the bacteroids, the former were fixed in 1/4 strength Karnovsky's fixative or 3% glutaraldehyde for 1.5 hours at room temperature. After overnight washing in 0.1 M cocadylate buffer pH 7.4 at 4 C, the trophozoites were placed in the incubation medium for acid phosphatase and then processed for electron microscopy.
Morphometric Analysis of Particulate Fractions from Rat Liver
Authors: Deter Russel L.
Published: June 2020

The morphological evaluation of fractions isolated by a variety of centrifugation methods has, until recently, been a qualitative one, based essentially on subjective impressions of small samples whose representativeness was not known. The lack of quantitative information about components of these fractions severely limited the usefulness of these morphologic data and made correlation with biochemical results rather difficult. In response to this situation, Baudhuin et al., and later Baudhuin and Berthet presented a method which circumvented previous problems and gave quantitative results directly comparable to those obtained by other methods. This method has been used in recent investigations concerned with the role of the lysosomal system in cellular autophagy carried out in this laboratory.
Alveolate Reticulum - An Alteration of Endoplasmic Reticulum Observed in Human Tissues
Authors: Uzman Betty G. , Kasac Marjorie
Published: June 2020

Electron microscopic studies of human tumors have been correlated by phase microscopy of ∼1μ sections with conventional histopathology. In tumor nodules from patients with fibrosarcoma (Fig. 1), malignant histiocytosis, and Hodgkin's disease (Figs. 2, 3, 4); in leukemic cells infiltrating spleen and lymph node; and in one parotid secretory cell (case of acute myeloblastic leukemia) alterations of the granular endoplasmic reticulum have been observed. These structures (indicated by arrows) resemble moth-eaten membranous bodies continuous with the encircling (Figs. 1, 2) or contiguous (Figs. 3, 4) cisternal wall. As many as five such alveolate reticular regions have been observed in a single cell.
Ciliated Granulosa Cells of the Bat, Myotis grisesoens
Authors: Appley Marlene B. , Richter Kenneth M.
Published: June 2020

Ultrastructural study of the bat ovary reveals ciliated granulosa cells in follicles of all stages of development. Figs. 1-4 show a developmental range of follicles from the very youngest (Fig. 1) to the near or mature follicle (Fig. 4).

The location and intracellular association of the cilia with the nucleus, Golgi complex and diplosome are the same in follicles of all degrees of development (Figs. 1-4). It seems significant that the cilium (c) of the granulosa cell is located consistently on that surface of the cell which is oriented toward the ovum (Figs. 1-4).

The cilia have a fiber pattern of 9+0, in contrast to the usual 9+2 (Fig. 2). Cilia of this type have been found in a wide range of dissimilar organs. They are limited to metazoans. Their presence provides no clue to the origin of the granulosa cells, since all three germ layers may give rise to ciliated cells.
Intramembranous Fibrils at Tight Junctions
Authors: Weinstein Ronald S. , McNutt N. Scott , Nielsen Surl L. , Pinn Vivian W.
Published: June 2020

The tight junction (zonula occludens) forms a linear region of contact between plasma membranes of adjacent epithelial cells near their juxtaluminar borders. This junction is a seal that prevents free diffusion between luminal and adluminal aspectsoof epithelia. At tight junctions in thin sections, the two apposed 75 Å plasma membranes join to form a membrane complex 140 Å in thickness. There is apparent “fusion” of the membranes with loss of outer leaflet material of one or both of the membranes. Previous interpretations of freeze-cleaved (and etched) tight junctions have been based on the Moor-Muhlethaler hypothesis that true membrane surfaces are revealed by cleaving. However, there is now compelling evidence that the surfaces revealed by cleaving are generated by splitting frozen membranes along a central plane thereby creating two new surfaces: Face A oriented toward the extracellular compartment and Face B directed toward the cytoplasm. We now describe a distinctive intramembranous fibrillar component in plasma membranes at tight junctions as revealed by membrane splitting.
Enumeration of Virus Particles in Thin Sectioned Pellets
Authors: Smith Kendall O. , Gehle Warren
Published: June 2020

Electron microscopists studying viruses during the last decade have concentrated heavily upon morphogenesis and viral ultrastructure. These efforts have borne rich harvests of important information about the macromolecular configuration of viruses and have strongly influenced the design of our present viral classification schemes. Viruses such as the Epstein-Barr herpes particle and several members of the “C”-particle class of viruses were recognized by electron microscopy before they could be effectively detected or quantitated biologically. Once such viruses are discovered, however, it is useful to know how many particles are present in certain materials. Thus, quantitation of virus particles (particle counting) has attracted the attention of those interested in viruses for which there is still no adequate biological detection or quantitation system.
Ultrastructural Lesions Produced by Alcohol and Sucrose in the Heart and Liver of C57BL Mice
Authors: SEKHRI K.K. , ALEXANDER C.S. , NAGASAWA H.T.
Published: June 2020

C57BL male mice (Jackson Lab., Bar Harbor, Maine) weighing about 18 gms were randomly divided into three groups: group I was fed sweetened liquid alcohol diet (modified Schenkl) in which 36% of the calories were derived from alcohol; group II was maintained on a similar diet but alcohol was isocalorically substituted by sucrose; group III was fed regular mouse chow ad lib for five months. Liver and heart tissues were fixed in 2.5% cacodylate buffered glutaraldehyde, post-fixed in 2% osmium tetroxide and embedded in Epon-araldite.
Retrieval of Paraffin Embedded Material for Ultrastructure Study
Authors: Clark T. S. , Rochlani S. P.
Published: June 2020

With the increasing use of electron microscopy in pathology, there appears to be an equally increasing need for the utilization of paraffin embedded material for ultrastructure study. Several investigators! have identified viruses in retrieved material, but made little comment on the ultrastructure of the tissue or the techniques involved. It is erroneous to assume that tissue fixed in formalin has no value for the ultrastructure pathologist.

We have analyzed the routine paraffin processed histological material to determine where and when loss of tissue and cell integrity occurs. In determining this site of “ultrastructure trauma” we have also tried various methods of retrieval of paraffin embedded material to prevent further loss of cellular structure.
Conformational Study of trna, Using the High Resolution Scanning Electron Microscope
Authors: Langmore J. , Wall J.
Published: June 2020

Individual molecules of yeast transfer RNA have been observed in the elastic dark field, inelastic dark field and “Z contrast” modes of the 5 Å high resolution scanning electron microscope. The operation, and contrast forming abilities of this instrument, are discussed elsewhere.

Of particular interest here is the fact that the contrast in this microscope is very high, so that negative staining techniques are not required. This does, however, present a problem in specimen preparation. The single tRNA molecules are approximately 30 Å thick and 50 to 150 Å long and are supported only by a thin carbon film. Difficulties are being experienced at the moment in preserving the structure of the molecules during the specimen preparation stage.
Light Optical Diffraction Studies of Macromolecular Ultrastructure
Authors: Haydon Glen B.
Published: June 2020

Analysis of light optical diffraction patterns produced by electron micrographs can easily lead to much nonsense. Such diffraction patterns are referred to as optical transforms and are compared with transforms produced by a variety of mathematical manipulations. In the use of light optical diffraction patterns to study periodicities in macromolecular ultrastructures, a number of potential pitfalls have been rediscovered. The limitations apply to the formation of the electron micrograph as well as its analysis.

(1) The high resolution electron micrograph is itself a complex diffraction pattern resulting from the specimen, its stain, and its supporting substrate. Cowley and Moodie (Proc. Phys. Soc. B, LXX 497, 1957) demonstrated changing image patterns with changes in focus. Similar defocus images have been subjected to further light optical diffraction analysis.
Microincineration and Scanning Electron Microscopy: Silica in Rice Hulls
Authors: S. Thomas Richard , T. Jones Francis
Published: June 2020

Microincineration has long been used to localize biological minerals by light microscopy, and recently the technique has been adapted for use with the transmission electron microscope1. From this, it seemed that the technique should also be useful in combination with the scanning microscope (SEM). An appropriate material for exploring this new combination is rice hulls. They contain about 20 percent mineral, and 99 percent of this is silica. The high silica content needs study since it hinders economic utilization or disposal of this important mill by-product. At the same time, it proves to be an asset in maintaining a three-dimensional ash structure for studying by SEM.
Sem Examinations of Glass Knives
Authors: Temple Black J.
Published: June 2020

There are two types of edge defects common to glass knives as typically prepared for microtomy purposes: 1) striations and 2) edge chipping. The former is a function of the free breaking process while edge chipping results from usage or bumping of the edge. Because glass has no well defined planes in its structure, it should be highly resistant to plastic deformation of any sort, including tensile loading. In practice, prevention of microscopic surface flaws is impossible. The surface flaws produce stress concentrations so that tensile strengths in glass are typically 10-20 kpsi and vary only slightly with composition. If glass can be kept in compression, wherein failure is literally unknown (1), it will remain intact for long periods of time. Forces acting on the tool in microtomy produce a resultant force that acts to keep the edge in compression.
Pre-shadowed Surface Replicas of Frozen Biological Specimens
Authors: Steere Russell L. , Haga J. Y.
Published: June 2020

A solid copper specimen cap without central hole serves as a flat surface for easy and rapid preparation of surface replicas of frozen biological specimens (1) in a Denton DFE-2 freezeetch apparatus (2). A thin film of 40% glycerol is spread over the flat upper surface of the cap, and small pieces of leaf, petal, or other tissue are placed on this moistened surface. Suspensions of cells or particulates may be spread thinly on a glass or metal plate which is then placed on the glycerol-coated cap. The freeze-etch module is flushed with ultra high-purity dry nitrogen gas, then the cap with specimens in place is clamped to the stage and the double shroud mechanism (3) moved inward to put the specimen in the inner chamber.
Morphologic Chahges in Testicular Interstitial Tissue of the Rat After Crtptorchidism or X-Irradiation
Authors: J. Niewenhuis Robert , R. Basom Charles , T. Binhammer Robert
Published: June 2020

Adult male rats were divided into five groups: (1 & 2) those surgically rendered either unilaterally cryptorchid or bilaterally cryptorchid; (3 & 4) those exposed to either unilateral or bilateral testicular x-irradiation and (5) a group of unilaterally cryptorchid animals which were treated with 100 I.U. of human chorionic gonadotrophin (HCG) for 21 days. Control animals were used for all groups. Tissues were fixed with glutaraldehyde using the whole body perfusion technique and post-fixed with osmium tetroxide. Epon 8l2 was used for embedment.

Ultrastructural examination of interstitial cells from cryptorchid and irradiated testes revealed basic changes in the amount and organization of the smooth endoplasmic reticulum (SER). In interstitial cells from control animals the SER was arranged primarily in the form of anastomotic tubules.
Detection of Influenza Virus Particles in Throat Washings by Electron Microscopy
Authors: B. Pendharker Mahadeo , A. Siegesmund Kenneth , D. Rose Harold , Piraino Frank , C. Kory Ross
Published: June 2020

Although the symptomatology of influenza is well known and fairly typical in most cases, the exact diagnosis is often presumptive because of the technical difficulties in performing laboratory tests. We have recently developed a method for concentrating and processing throat washings to provide a cell block which can be sectioned for ultrastructural study. We have used this technique for studying the throat washings from five sero-logically proven patients with Influenza A2 Hong Kong infection. Two ml of throat washings were mixed with 0. 5 ml of a fixative containing 2% acrolein, 3% glutaraldehyde in phosphate buffer at pH 7. 2 in a centrifuge tube. A disc of filter paper (Whatman #41 ashless) 5 mm in diameter was placed in the centrifuge tube, and the samples were centrifuged at 18,000 rpm for one hour.
Measurement of Radial Distortion
Authors: Reisner John H .
Published: June 2020

Radial distortion is not usually an important problem in electron microscopy, and can in many applications be tolerated in amounts up to ten percent. However, when accurate quantitative results are required, or when a montage of photomicrographs is to be prepared, radial distortion must be taken into account.

The scheme described for the measurement of radial distortion grew out of a need for a short procedure simple enough to be described over the telephone, and not requiring special or unusual test specimens. The procedure is undoubtedly not new; but the writer has never seen it published or used elsewhere, and in response to several suggestions has prepared it for publication.
Contrast & Resolution in Scanning Electron Microscopy using Backscattered Electrons
Authors: Ong P.S.
Published: June 2020

Primary backscattered electrons are not widely used in scanning electron microscopy, despite the fact that they exhibit properties which cannot be duplicated by the use of secondary electrons. Among these are:

The backscatter coefficient depends strongly on the average atomic number of the specimen.

The angular distribution of the backscattered electrons is similar to that of light, interacting with a diffuse sample. i.e., it exhibits a cosine distribution for normal incidence and approaching total re flection at grazing angles.

By virtue of their high energy, they are not affected by small elec tric and magnetic fields, and thus travel in straight lines.
A Comparison of TEM and SEM Fractography
Authors: Hubbard James L.
Published: June 2020

For many years now, metallurgists have been using replica techniques for electron micrographic studies of the fracture surfaces of metals. The general features which are indicative of a certain mode of fracture, such as fatigue, overstress, or stress corrosion, have become quite familar in a wide variety of alloys. Although replicas are subject to many artifacts these features are usually recognized as such and disregarded in the analysis of the surface. Also since negative replicas are generally used one must reverse his perspective in order to obtain a true mental picture of the fracture surface.

With the scanning electron microscope, micrographs of such samples can now be taken directly with no surface replication or preparation involved. The scanning micrographs, while limited in resolution, present a picture not only true to the surface but with a stereo perspective with which one can relate the surface features to reality.
Solid Solution Effects and Deformation Micros trueture of Shock-Loaded Iron Manganese Alloys
Authors: Christou A. , Foltz J. V. , Brown N.
Published: June 2020

In general, all BCC transition metals have been observed to twin under appropriate conditions. At the present time various experimental reports of solid solution effects on BCC metals have been made. Indications are that solid solution effects are important in the formation of twins. The formation of twins in metals and alloys may be explained in terms of dislocation mechanisms. It has been suggested that twins are nucleated by the achievement of local stress-concentration of the order of 15 to 45 times the applied stress. Prietner and Leslie have found that twins in BCC metals are nucleated at intersections of (110) and (112) or (112) and (112) type of planes.

In this paper, observations are reported of a transmission microscope study of the iron manganese series under conditions in which twins both were and were not formed. High strain rates produced by shock loading provided the appropriate deformation conditions. The workhardening mechanisms of one alloy (Fe - 7.37 wt% Mn) were studied in detail.
The Ultrafine Structure of Carbon Fibers
Authors: Phillips V. A. , Hugo J. A. , Roberts B. W.
Published: June 2020

High resolution phase contrast microscopy has been used to study the ultrafine structure of Morganite I and Thornel high modulus carbon fibers. Both are commercial fibers processed at 2800° to 3000°C, the former made from a polyacrylonitrile and the latter from an cellulose (rayon) precursor. Graphitizing is combined with stretching in order to align the basal planes parallel to the fiber axis to secure the high modulus. The ultrafine structures of these fibers have previously proved elusive.

The fibers have been looked at in two ways. Since they are irregular in shape it was found possible to direct the electron beam normal to the fiber axis and image the basal planes viewed edge-on at the periphery of a fiber. The image disappears as one moves into the thicker region, so that only the structure near the surface is accessible. The second approach was to fracture the fiber by applying local bending stresses.