bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Streptozotocin-Induced Diabetes on Estradiol-Stimulated Changes in the Ultrastructure of the Rat Endometrium
Authors: Frederick G.T. , Gardner R.M. , Kirkland J.M. , Stancel G.M.
Published: June 2020

Estradiol (E2)-stimulated uterine growth has been well characterized both biochemically and morphologically. Recent studies have shown that insulin plays an important role in the regulation of cellular development. This study examines the effect of streptozotocin-induced diabetes on E2-stimulated changes in the ultrastructure of the endometrium of the rat uterus.

Sprague-Dawley rats were ovariectomized at 21 days of age. Diabetes, defined as blood glucose levels greater than 300mg%, was induced in half of these animals by the injection of 85mg streptozotocin/kg body weight.The remaining animals were classified as normal. Animals from both groups were injected with either 0.9% saline or 4μg E2/100gm body weight. At 18, 24, 36 and 48 hours post-injection of E2, uterine segments were collected from 8-10 animals in each experimental group and processed for electron microscopic examination. Uterine segments from saline-injected animals served as controls. Data summarized describe observations made from thin-sections and have not been extrapolated for whole cells.
The Response of Testis Cells to Low Dose X-Irradiation
Authors: E. Philpott D. , Sapp W. , Williams C. , Stevenson Joann , Black S.
Published: June 2020

The response of spermatogonial cells to X-irradiation is well documented. It has been shown that there is a radiation resistent stem cell (As) which, after irradiation, replenishes the seminiferous epithelium. Most investigations in this area have dealt with radiation dosages of 100R or more. This study was undertaken to observe cellular responses at doses less than 100R of X-irradiation utilizing a system in which the tissue can be used for light and electron microscopy.

Brown B6D2F1 mice aged 16 weeks were exposed to X-irradiation (225KeV; 15mA; filter 0.35 Cu; 50-60 R/min). Four mice were irradiated at each dose level between 1 and 100 rads. Testes were removed 3 days post-irradiation, fixed, and embedded. Sections were cut at 2 microns for light microscopy. After staining, surviving spermatogonia were identified and counted in tubule cross sections. The surviving fraction of spermatogonia compared to control, S/S0, was plotted against dose to give the curve shown in Fig. 1.
The Grid-All: A Multiple Grid Handling, Staining, and Storage Device for Use in Electron Microscopy
Authors: Giammara Beverly
Published: June 2020

A number of methods, including those reviewed by Hayat, have been devised for holding and staining groups of grids. The Grid-All (Polysciences, Inc.), however, has additional functions, including the collection of grids serially from the ultramicrotome, transport, staining, washing and storage, all in the same module (Fig. 1). The grids are kept securely locked and serially held by the Grid-All through all the procedures to which grids are subjected. Grid-Alls have been made in different sizes to hold groups of 3,5,10 or 15 grids. The largest 15-slot Grid-All can be cut to make smaller units, if desired.

The Grid-All is made of a flexible RTV Silastic material that allows insertion of any kind of grid, including tabbed or slotted, when it is flexed (Fig. 2). When relaxed, the material grips the grids tightly in its slots. Protective posts prevent mechanical damage to the grids being held, even if the holder is dropped.
Sachharide Staining in Thin Sections
Authors: Marenus K. , Kuhn E. , Beer M.
Published: June 2020

A specific reagent for the glycol groups of sugars yields similar staining patterns in isolated or embedded and thin sectioned rat tail tendon. These results suggest that the stain specificity and the structure of the protein fibers are retained after cross linking, embedding and thin sectioning.

Osmate in the presence of tetramethylethylenediamine (TEMED) binds to glycols and has been found to stain sugar residues. SLS aggregates, in which adjacent molecules lie in exact register, can be formed by addition of ATP to collagen monomers. Osmate-TEMED staining of these has produced a specific band in Type I collagen at a known glycol position 10% along the molecule from the N-terminal end. We have observed a second band 10% from the C-terminal end (Fig. 1) which is also faintly visible in. In addition, other weak bands have been observed.
Hingeless Complementary Specimen Holders for the Denton Freeze-Etch Apparatus
Authors: Steere Russell L. , Erbe Eric F.
Published: June 2020

A major complication in the use of complementary specimen holders in the Denton freeze-etch apparatus has been breakage of the holders due to the freezing of specimen liquid within the hinges. The hinged holders (Steere and Moseley, 1970) were designed with gaps to prevent capillary movement of specimen liquid into the hinge. Nevertheless, some holders were manufactured with insufficient gaps and many operators fail to take sufficient precautions in sample loading which results in the breakage of specimen holder hinges.

In order to avoid such problems, we have developed a new specimen cap and new complementary specimen holders without hinges (Fig. 1). Because of the simple design of the holders, they can be cut out by hand or by use of a specially designed punch. They can be made in different widths and out of various metals or plastics. Specimen slots of any desired size or orientation can be cut into the opposing faces of the complementary halves of specimen holders.
A Comparison of the Ultrastructural Morphology of Hepatic Necrosis in BDF1 Mice
Authors: Jackson Becky
Published: June 2020

Preliminary investigation has indicated similarity in hepatic ultrastructural morphology in nutritional deprivation, and cyanide induced hepatic necrosis. Analysis of hepatic tissue has indicated disruption of intracellular membranes, specifically, reduction in rough endoplasmic reticulum (RER) mitochondrial integrity, and glycogen stores. An increase in smooth endoplasmic reticulum (SER) portion was observed.

To further investigate the apparent equivalence of necrotic morphology, ultrastructura1ly, BDF1 mice were subjected to senescence, nutritional deprevation, potassium cyanide (KCN) induced toxemia, and acetaminophen induced toxemia. Controls were utilized to ellucidate non-necrotic hepatocellular normals. U1trastructura1 investigation of controls (Fig. 1) shows densely granular RER, abundant glycogen stores, and morphologically normal mitochondria. Subjects with acetaminophen induced necrosis exhibit reduced normal RER with increased levels of dialated, vesicular RER in apparent conversion to SER (Fig. 2), loss of mitochondrial integrity, and glycogen store reduction. Senescent subjects exhibit a pronounced increase in SER and loss of glycogen store. (Fig. 3). Investigation of the senescent SER at high magnification (Fig. 5) indicates that the SER is arising from degranulating and vesiculating RER.
Method for the Ultrastructural Evaluation of Rodent Nasal Mucosa
Authors: Popp James A. , Martin Joseph T.
Published: June 2020

In recent years extensive ultrastructural studies of the pulmonary system have been published. Many of these studies have been initiated to clarify the effects of air pollutants and inhaled gases on tracheal mucosa, intrapulmonary air passages and alveoli. Although light microscopic evaluation of the nasal mucosa has been included in some recent morphologic studies of the effects of inhaled toxicants, the ultrastructural effects on nasal mucosa have rarely been published. This lack of information is primarily due to the difficulty of preparing the epithelial mucosa for examination since it is completely encased in bone. We have developed a detailed systematic method to prepare any site in the rat nasal mucosa for ultrastructural evaluation by both transmission and scanning electron microscopy.

Fixation is achieved by an intravascular perfusion technique using meto- fane (Pitman Moore, Inc.) anesthetized 200 gram Fischer-344 rats. The perfusing catheter is inserted through the left ventricle and into the ascending aorta.
A Preliminary Study of Thin Bird Disease
Authors: Davis Ronald W. , Kenzy Samual , Stauber Erik H.
Published: June 2020

We have initiated a study of a disease that is usually fatal to domestic parakeets and canaries. We have called this syndrome “thin bird disease” for lack of a better name.

Clinically, the disease is diagnosed after observing a bird that is thin, exhibits severe weight loss, lethargy, and ruffled feathers. Fecal smears of affected birds contain many very large, single-celled, rod-shaped bacteria measuring up to 1μm x 90μm.

Post mortem examination of birds exhibiting external symptoms of the disease reveals an enlarged ventriculus (gizzard) that contains unmacerated seeds. A jelly-like mass is found in the ventriculus and pro-ventriculus of affected birds. This material contains bacteria morphologically identical to those found in fecal smears (Figs. 3, 4).

Samples of ventriculus and pro-ventriculus from birds clinically diagnosed as diseased and normal were collected and processed for light microscopy, scanning and transmission electron microscopy. The specimens were fixed in half strength Karnovsky's fixative, post fixed in OsO4, and either embedded in plastic or critical point dried.
Virus-Like and Membrane-Bound Particles in the Venom Apparatus of a Parasitoid Wasp (Hymenoptera:Braconidae)
Authors: Edson Karthryn M.
Published: June 2020

Successful parasitism of a host by a parasitoid wasp may be aided by secretions from the venom apparatus, an accessory gland of the female parasitoid's reproductive system. In the present study, transmission electron microscopy of the venom apparatus of Meteorus leviventris reveals virus-like and membrane-bound particles which may influence successful parasitism of the host. This is the first evidence of such particles within the venom apparatus of a parasitoid.

The venom apparatus of M. leviventris consists of a venom reservoir with two highly ramified gland filaments attached to it by a common duct.TEM of the secretory cells of the gland filaments reveals particles approximately 50 nm in diameter contained within a cytoplasmic stroma (Fig. 1). These virus-like particles (VLP) have a dense inner core and a hexagonal congifuration. Similar particles are found free within the cytoplasm or associated with vacuoles (Fig. 2).

Secretory cells of the gland filaments contain a secretory apparatus which consists of an array of microvilli converging on a central lumen (Fig. 3).
New Ultrastructural Observations on Injury and Regeneration of Cilia in Mammalian Conducting Airway Epithelium
Authors: Carson J.L. , Collier A.M.
Published: June 2020

The ciliated cells lining the conducting airways of mammals are integral to the defense mechanisms of the respiratory tract, functioning in coordination with secretory cells in the removal of inhaled and cellular debris. The effects of various infectious and toxic agents on the structure and function of airway epithelial cell cilia have been studied in our laboratory, both of which have been shown to affect ciliary ultrastructure.

These observations have led to questions about ciliary regeneration as well as the possible induction of ciliogenesis in response to cellular injury. Classical models of ciliogenesis in the conducting airway epithelium of the mammalian respiratory tract have been based primarily on observations of the developing fetal lung. These observations provide a plausible explanation for the embryological generation of ciliary beds lining the conducting airways but do little to account for subsequent differentiation of ciliated cells and ciliogenesis during normal growth and development.
Electron-Immuno-Cytochemistry: Peroxidase-Labeled Antibody Method
Authors: Nakane Paul K.
Published: June 2020

The application of immunohistochemistry to electron microscopy is a natural extension of the immunofluorescent technique developed by Coons for light microscopy. The lack of electron density of fluorescein has necessitated a search for a label with high electron density suitable for ultrastructural use. The label should be attached to the antibody by stable linkages, should not exhibit specific interactions with other proteins or chemicals, should not be too large in order to avoid stereo effects that might interfere with the mobility of the labeled antibody, and must remain stable and withstand the adverse physical conditions presented with electron microscopy. In search for such a label, enzymes of small molecular weight were conjugated to antibodies employing bi-functional reagents. The enzymatically and immunologically active conjugates were reacted with tissues which were then stained histochemically for the enzymes. Horseradish peroxidase was employed since it was stainable histochemically with stable reaction products visible with light and electron microscopes. In addition its endogenous localization was limited to specific sites. This system is highly sensitive because of an amplifying effect. Enzyme is not consumed in the reaction with substrate and each molecule of enzyme-labeled antibody bound to the antigenic site deposits many molecules of reaction product.
Fine Structural Localization of Membrane ATPase Activity in the Choroid Plexus and Ependyma of the Guinea Pig
Authors: Beggs John
Published: June 2020

It is generally accepted that the choroid plexus plays an active role in the formation of cerebrospinal fluid. Present evidence suggests that its specific function is to transport sodium into the ventricular cavity. Since membrane-bound ATPase has been implicated in cation transport in various cells and tissues, this study was designed to localize this activity in the choroid as well as the ependyma at the ultrastructural level.

The final reaction product resulting from hydrolysis of ATP in the Wachstein-Meisel media was deposited at specific sites along the plasmalemmata (no deposits occurred when B-glycerophosphate was substituted, or when ATP was omitted from the incubation media). In the choroid, reaction product at the apical surface was found to have a random pattern on: a) microvilli and cilia, b) on the plasmalemma between microvilli, c) within coated vesicles at and near the surface (Fig. 1). Lateral membranes and their inter-digitations showed sparse reaction product. The highest activity was exhibited at the basal plasmalemma where deposits followed a uniform pattern along cytoplasmic infoldings and vacuoles (Fig. 2).
Cytochemistry of Membrane-Associated Cytochrome Oxidase in Azotobacter Vinelandii
Authors: Gardner J. N. , Lin L. P. , Socolofsky M. D.
Published: June 2020

Young, vegetative cells of the nitrogen-fixing bacterium, Azotobacter vinelandii, contain invaginations of the cytoplasmic membrane. These typical procaryotic cells are characterized by the absence of both a nuclear membrane and organelles such as Golgi bodies and mitochondria (Fig. 1). Although mitochondria are the organelles responsible for electron transport and respiratory operations in eucaryotic organisms, the electron transport function of procaryotic cells is attributed to the membranous structures. In the present study an attempt was made to visualize the site of cytochrome oxidase activity using methods of cytochemistry and electron microscopy.

The classical method for the demonstration of cytochrome oxidase activity is the Nadi reaction; the two reagents of this reaction are 1-naphthol and p-phenylenediamine. A substituted p-phenylenediamine, N-benzyl-p-phenylenediamine (BPDA), was used successfully by Seligman et al in the demonstration of cytochrome oxidase activity. This reagent reacts readily with 1-naphthol to form an osmiophilic quinoneimine group resulting in the transfer of electrons to cytochrome c which is subsequently oxidized by cytochrome oxidase. The quinoneimine group reacts with OSO4 to yield an electron dense pigment at the site of cytochrome oxidase activity.
Fine Structure of Bacteria Grown in the Presence of Acriflavine
Authors: Boatman Edwin S.
Published: June 2020

The effect of acridine derivatives on bacterial growth has been shown to be dependent upon the concentration used, pH, temperature, and the position of the amino substituents on the acridine molecule. These factors, in turn, affect the amount of acridine bound to cell constituents. Many bacterial species, when grown in media containing acridities, become filamentous, or pleomorphic, or growth may be entirely prevented. The fine-structure of two species of bacteria treated with acriflavine was investigated. Both were Gram-positive bacilli, one was a Corynebacterium, and the other an aerobic spore-bearing Bacillus.

Organisms were incubated at 21°c in the presence of concentrations of acriflavine ranging from 0.25 ug/ml to 12 ug/ml in phosphate buffered peptone water yeast extract medium at pH 7.5. Viable counts were carried out and the amount of acriflavine bound, either reversibly or irreversibly, was estimated at 450 mu, using a DB spectrophotometer. Cultures were observed by light microscopy and, after four days growth, were processed for electron microscopy by fixation in veronal-acetate pH 6.1 buffered 0.8% Os O4 for one hour and embedding in Epon 812 resin.
Cell Wall Particles from E. Coli
Authors: Slayter H. S. , Nisbet John H.
Published: June 2020

A number of reports have appeared recently concerning the nature of the cell wall of E. coli (e. g. ref. 1). It has been shown that the region between the outer layer of the cell wall and the inner layer of the plasma membrane consists of strata of protein, lipid, polysaccharide and their complexes. It is also known that the space between the cell wall and the plasma membrane contains substantial activities of various enzymes, such as alkaline phosphatase and acid phosphatase. Micrographs of sections of E. coli often show vesicles which appear to be detached from the cell wall. These range upward from 200Å in diameter. In certain lysine-limited mutants of E. coli a substantial quantity of similar material has been isolated under conditions of lysine deprivation. This material has been characterized chemically (ref. 2).
Some Conditions Necessary for Pinocytosis
Authors: Brightman M. W.
Published: June 2020

The cytological evidence for pinocytosis is the focal infolding of the cell membrane to form surface pits that eventually pinch off and move into the cytoplasm. This activity, which can be inhibited by oxidative and glycolytic poisons, is performed only by cell processes that are at least 300A wide. However, the interpretation of such toxic effects becomes equivocal if the membrane invaginations do not normally lead to the formation of migratory vesicles, as in some endothelia and in smooth muscle. The present study is an attempt to set forth some conditions under which pinocytosis, as distinct from the mere inclusion of material in surface invaginations, can take place.
Nucleolar Segregation in Cells of Untreated Mouse Lymph Node
Authors: Arnold Wm. James , Albert S.
Published: June 2020

Certain cells which often form prominent populations in mouse lymph nodes have the morphological characteristics of, and parallel the development of, young erythroid cells. These cells produce no histochemically detectable amounts of hemoglobin and bear no indication of full-scale nuclear extrusion. Their nucleoli persist beyond the state of development at which nucleoli disappear from erythroid cells of the bone marrow and spleen. In their persistence, these nucleoli display a structure which is very similar to the “segregation” often found in nuclear intoxication.

Profiles of these nucleoli seen in electron micrographs lie usually in contact with condensed chromatin and often appear to be completely surrounded by it (Figure 1). They have the internal appearance of being made up of two or three discrete components each separate from the others. The outer layer is composed of granules about the size and shape of cytoplasmic ribosomes, packed together to an extent intermediate between the interchromatin and the chromatin (Figure 2). Inside the granular shell there are one or several aggregations of fibrillar material, often forming a circular profile (Figure 2). In most nucleoli a third component is present and consists of clusters of darkly staining granules similar to the chromatin but lying within the nucleolus, frequently at the interface of the other components (Figure 3).
The Localization of a Peroxidase Associated With the Formation of Hard Cuticle in Insects
Authors: Locke M.
Published: June 2020

Plant peroxidase has been used to trace the uptake of proteins from the blood into multivesicular bodies and storage granules in several insect tissues. Control experiments without plant peroxidase show that an endogenous peroxidase may also be present at some stages, particularly in epidermal cells during the formation of hard brown cuticle. It occurs in granules about 5μ in diameter and is most easily demonstrated in Calliphora epidermis before puparium formation and in the cells forming the proleg spines in Calpodes larvae (Fig. 1). These granules have the structure of MVB's (Fig. 2) and contain acid phosphatase. Since MVB's are usually regarded as organelles for heterolysis, this location for the endogenous enzyme was difficult to reconcile with a functional relation to hard cuticle formation. The paradox was resolved by a study of the proleg spine cells during cuticle formation.
Investigation of the Origin of the Crystal Containing Cell in the Caecal Epithelium of the Mouse
Authors: Wesley R. K. Anthony , Jensen Thomas E.
Published: June 2020

The crystal containing cell has been found in portions of the large and small intestine of the mouse. The cells are usually located at the basal aspect of the epithelium and contain intracytoplasmic inclusions which demonstrate a 60 A lamellar periodicity (Fig. 1) when the plane of sectioning is perpendicular to the crystal lattice. The purpose of this study is to determine if the crystal containing cells are of true epithelial origin or if they originate from a migratory cell type which enters the epithelium from the lamina propria and then differentiates.

12 mice were administered intraperitoneal injections of actinomycin D in the following divisions: Group I, 23 ug actinomycin D during a 24 hour period; Group II, 33 ug during 48 hours; Group III, 40 ug over 52 hours; and Group IV, 63 ug over 72 hours. Examination of the caecal epithelia with the electron microscope revealed an increase in the number of crystal containing cells in the treated animals (Fig. 3) over the controls which were injected with corresponding amounts of physiological saline. Control epithelia have crystal cells in about 1-2% of the total cell population, whereas the treated mice epithelia have crystal cells in approximately 20%, or more of the total cells. A large number of migratory cells may have invaded the intestine in response to the peritoneal inflammation established during actinomycin D administration. The increased number of crystal cells in treated mice probably developed from the increased migratory cell population. Since low levels of actinomycin inhibit mitoses in mammalian cell lines, the increase in the number of crystal containing cells in the epithelium could not have been from divisions of the pre-existing cells originally present in the epithelium.
Scanning Microscopy of Human Blood and Marrow Smears
Authors: McDonald L. W. , Hayes T. L.
Published: June 2020

The scanning electron microscope (SEM) permits direct observation of standard light microscope slide and cover slip preparations. Single cells can be located and identified in the two instruments and the higher resolution, three dimensional image of the SEM can be correlated with the classic cytological information contained in the light microscope image.

Samples of peripheral blood and bone marrow were obtained from patients with chronic lymphatic leukemia and polycythemia. A drop of either blood or bone marrow from the syringe used for drawing the specimen was placed on alcohol cleaned, 22 mm square cover glasses. A second cover glass was placed over the drop of blood or marrow and the two cover glasses drawn apart in the manner usual for preparing blood and marrow for examination by light microscopy. These cover slips were rapidly air dried and then stained for examination by light microscopy. The staining procedure consisted of flooding the cover glass with Jenner's stain for 5 minutes, adding distilled water to cover the glass for another 5 minutes and then washing in tap water. Following this a Giemsa stain made up freshly from the stock solution was applied to the cover glass for 10 minutes. The cover glass was then washed and air dried. A thin coating of platinum-paladium was applied in a vacuum evaporator to facilitate electrical conduction.
Incomplete Maturation of Iridal Pigment in Heterochromia Iridum
Authors: Shively James N. , Phemister Robert D.
Published: June 2020

Heterochromia is an abnormality of iridal pigmentation characterized by marked differences in the color of the two irides or in segments of one iris. The affected areas are pale blue to grayish white. The condition is known to be present in a variety of species including man, dog, mouse, rabbit, cat, pig, and horse. In some species heterochromia has been transmitted as an autosomal dominant trait. It is also a dominant characteristic in Waardenberg's oculo-dermato-auditive syndrome. In several breeds of dogs heterochromia is associated with merle (or harlequin or dappled) coat color which is controlled by an autosomal dominant gene. Other factors are involved in Fuch's heterochromic cyclitis.

The present study resulted from the spontaneous occurrence of 5 cases of heterochromia in a large colony of beagles produced to study the long-term effects of low doses of radiation administered at various ages. When ten weeks old (3 or 4 weeks after the dog eye has attained adult characteristics), the affected dogs were anesthetized with pentobarbital sodium. The eyes were extirpated and quickly hemisected dorsoventrally. One calotte was fixed in cold glutaraldehyde-acrolein for 90 minutes. Representative blocks through the iris were cut and stored in phosphate buffer (pH 7. 3) overnight, washed in veronal-acetate buffer, pH 7.3, and post-fixed in 2% OsO4 in veronal-acetate buffer. Further processing was by standard techniques. The sections were stained with uranyl acetate and lead citrate. The other calotte was fixed for 24 hours in 6.25% glutaraldehyde for light microscopy. The calotte was rinsed in phosphate buffer, pH 7.3., embedded in paraffin, sectioned at 6μ and stained with hema-toxylin and eosin.
Intestinal Absorptive Epithelium in Wolman's Cholesterol Lipidosis
Authors: Partin John C. , Mereu Tullio R. , Schubert William K.
Published: June 2020

Wolman's cholesterol lipidosis is a rare genetic disorder of lipid metabolism in which large amounts of chemically normal cholesterol and triglyceride are accumulated in tissues, particularly liver, spleen, skin, adrenal and intestine. Affected infants develop vomiting, diarrhea, wasting and enlargement of the liver and spleen during the first weeks of life. Characteristic enlargement and calcification of the adrenal glands are present by x-ray. Most of the children die in early infancy.

This is the first report of electron microscopy (EM) of small intestinal absorptive epithelium in Wolman's disease. Mucosa was obtained by peroral biopsy from a 6 month old affected infant. The tissue was divided and prepared for lipid staining in frozen sections and for electron microscopy. Lipid stains demonstrated large amounts of lipid in the absorptive but not the crypt epithelium. Serial sections were made of the osmium fixed villi through the absorptive epithelium. Remarkable EM changes were present in thelysosomes, thesmooth endoplasmic reticulumand theGolgi system: Lysosomal vacuoles below the terminal web contained large amounts of dense material as well as electron “lucent” crystal-like images, possibly cholesterol or its esters. Smooth endoplasmic reticulum was prominent and contained many osmiphilic droplets. In the ectoplasm near the plasma membrane great cylindrical whorls of crinkled membrane seemed to arise in association with smooth endoplasmic reticulum, frequently wound around a mitochondrion. In the Golgi system, peripheral vesicles were distended with uniform droplets about. μ in diameter resembling chylomicrons.
Comparison of Normal and Thrombasthenic Human Blood Platelets
Authors: Rodman N. F. , Painter J. C. , Mason R. G.
Published: June 2020

The ultrastructure of normal human blood platelets in the resting state has been described in detail. Platelets recovered from citrated plasma of a patient with Glanzmann's thrombopathy or thrombasthenia have a similar appearance (Fig. 1). These anucleate cells are usually disc shaped and hence are round or oval, depending upon the plane of sectioning. They have randomly dispersed cytoplasmic organelles and microtubules which are typically arranged in a marginal band.

Platelet responses to several agglutinating agents and the relation of platelets to fibrin during clotting have been reported. On exposure to thrombin, to ADP, or to collagen, normal and thrombasthenic platelets undergo similar early morphologic changes. Pseudopods form and organelles move toward platelet centers, with microtubules being outermost of the closely packed, centrally apposed organelles. A peripheral rim of cytoplasm is essentially organelle-free except for an occasional mitochondrion or vacuole and except for microtubules which sometimes extend outward into pseudopods. Following these early, preagglutination changes normal platelets agglutinate in response to each of the 3 agglutinating agents, whether in autologous plasma or in salt solution after repeated washings. Thrombasthenic platelets in autologous plasma fail to agglutinate in response to thrombin or to ADP and agglutinate only minimally on exposure to finely divided collagen.
Biological and Morphological Studies on Low-Leukemia-Strain Mice with Hodgkin's-Like Neoplasia Induced by Serial Cell-Free Transmission of Leukemic Organs of SJL/J Strain Mice
Authors: Fujinaga S. , Maruyama K. , Williams C.W. , Sekhri K. , Dmochowski L.
Published: June 2020

Yumoto and Dmochowski (Cancer Res.27, 2098 (1967)) reported the presence of mature and immature type C leukemia virus particles in leukemic organs and tissues such as lymph nodes, spleen, thymus, liver, and kidneys of SJL/J strain mice with Hodgki's-like disease or reticulum cell neoplasm (type B). In an attempt to ascertain the possibility that this neoplasia may be of viral origin, experiments with induction and transmission of this neoplasm were carried out using cell-free extracts of leukemic organs from an SJL/J strain mouse with spontaneous disease.

It has been possible to induce the disease in low-leukemia BALB/c and C3HZB strain mice and serially transfer the neoplasia by cell-free extracts of leukemic organs of these mice. Histological examination revealed the neoplasia to be of either reticulum cell-type A or type B. Serial transfer is now in its fifth passage. In addition leukemic spleen from another SJL/J strain mouse with spontaneous reticulum cell neoplasm (type A) was set up in tissue culture and is now in its 141st serial passage in vitro. Preliminary results indicate that cell-free material of 39th tissue culture passage can reproduce neoplasia in BALB/c mice.
A Versatile, Sensitive Photometer For Electron and Optical Micrography
Authors: Drogosz F. B. , Hungerford W. R. , Bigelow W. C.
Published: June 2020

Many electron microscopes manufactured during the last decade were not equipped with exposure meters. The addition of exposure meters to these instruments greatly increases their efficiency and effectiveness. The photometer described here was developed particularly for this purpose and has been used for a number of years with highly satisfactory results. It is, however, quite versatile and, with appropriate modifications, has been found equally satisfactory for use in macro- and microphotography, photographic enlarging, turbidimetry, etc.

This photometer uses the simple triode cathode-follower circuit shown in Fig. 1 to amplify the response of an inexpensive CdS-SdSe type photocell whose electrical resistance Rc decreases with increasing intensity of illumination. In this circuit, the meter reads the cathode current of the troide which is controlled by the voltage Eg applied to its grid. The grid is connected to a voltage divider composed of the photocell and two sensitivity adjusting resistors Rs, so that Eg = VRc/(Rc + Rs).
Further Ultrastructural Observations on Metastatic Nodules of Human Breast Cancer
Authors: Swedo John L. , Talley R. W. , Watson John H. L.
Published: June 2020

Since the report, which described the ultrastructure of a metastatic nodule of human breast cancer after estrogen therapy, additional ultrastructural observations, including some which are correlative with pertinent findings in the literature concerning mycoplasmas, have been recorded concerning the same subject. Specimen preparation was identical to that in.

The mitochondria possessed few cristae, and were deteriorated and vacuolated. They often contained particulates and fibrous structures, sometimes arranged in spindle-shaped bundles, Fig. 1. Another apparent aberration was the occurrence, Fig. 2 (arrows) of linear profiles of what seems to be SER, which lie between layers of RER, and are often recognizably continuous with them.

It was noted that the structure of the round bodies, interpreted as within autophagic vacuoles in the previous communication, and of vesicular bodies, described morphologically closely resembled those of some mycoplasmas. Specifically, they simulated or reflected the various stages of replication reported for mycoplasmas grown on solid nutrient. Based on this observation, they are referred to here as “mycoplasma-like” structures, in anticipation of confirmatory evidence from investigations now in progress.
Freeze-Etching of Intercellular Junctions of Mouse Liver
Authors: Kreutziger G. O.
Published: June 2020

The tight junction at the bile canniculus of mouse liver contains a packed hexagonal particle array in the intercellular space. This region has been identified in freeze-etch preparations revealing several additional structures.

Mouse liver is fixed in 2% purified glutaraldehyde for 2 hours and infiltrated with 20% glycerine for 1/2 hour. Fixative and cryoprotective solutions are prepared in sodium-free Krebs-Ringer phosphate pH 7.2 to 7.4 and the solutions are oxygenated before use. Fixation and infiltration are conducted at room temperature prior to quick freezing in liquid propane. Freeze-etch replicas are produced with a modified simple freeze-etch device, cleaned with “Clorox”, washed with distilled water and examined unsupported on 300 mesh grids in a Seimens Elmiskop 1A.

Two different views of the Plasmalemma are observed (Fig.1). The intercellular surface is identified by the hexagonal particle array. Outside the tight junction this surface has a dense randomly distributed particle population. Viewed from the intracellular surface a circumscribed area reflects the closer membrane apposition of the occluding junction.
Voids in Quenched Nickel
Authors: Laidler J. J.
Published: June 2020

The presence of three-dimensional voids in quenched metals has long been suspected, and voids have indeed been observed directly in a number of metals. These include aluminum, platinum, and copper, silver and gold. Attempts at the production of observable quenched-in defects in nickel have been generally unsuccessful, so the present work was initiated in order to establish the conditions under which such defects may be formed.

Electron beam zone-melted polycrystalline nickel foils, 99.997% pure, were quenched from 1420°C in an evacuated chamber into a bath containing a silicone diffusion pump fluid . The pressure in the chamber at the quenching temperature was less than 10-5 Torr . With an oil quench such as this, the cooling rate is approximately 5,000°C/second above 400°C; below 400°C, the cooling curve has a long tail. Therefore, the quenched specimens are aged in place for several seconds at a temperature which continuously approaches the ambient temperature of the system.
Microstructure of Electro-Eroded Cemented Carbide Surfaces
Authors: Filimonenko V. N. , Richman M. H. , Gurland J.
Published: June 2020

The high temperatures and pressures that are found in a spark gap during electrical discharging lead to a sharp phase transition and structural transformation in the surface layer of cemented carbides containing WC and cobalt. By means of X-ray diffraction both W2C and a high-temperature monocarbide of tungsten (face-centered cubic) were detected after electro-erosion. The W2C forms as a result of the peritectic reaction, WC → W2C+C. The existence and amount of the phases depend on both the energy of the electro-spark discharge and the cobalt content. In the case of a low-energy discharge (i.e. C=0.01μF, V = 300v), WC(f.c.c.) is generally formed in the surface layer. However, at high energies, (e.g. C=30μF, V = 300v), W2C is formed at the surface in preference to the monocarbide. The phase transformations in the surface layer are retarded by the presence of larger percentages of cobalt.

Metallographic examination of the electro-eroded surfaces of cemented carbides was carried out on samples with 5-30% cobalt content. The specimens were first metallographically polished using diamond paste and standard procedures and then subjected to various electrical discharges on a Servomet spark machining device. The samples were then repolished and etched in a 3% NH4OH electrolyte at -0.5 amp/cm2. Two stage plastic-carbon replicas were then made and shadowed with chromium at 27°.
A High Vacuum Electron Microscope
Authors: Braski D. N.
Published: June 2020

Improved vacuum levels have already been achieved in the electron microscope column or in the specimen chamber. However, little has been done to modify the microscope structure for compatibility with the ultimate high vacuum-low contamination conditions desired for in situ evaporation studies. In our laboratory, a Hitachi HU-11B electron microscope (Fig. 1) has been modified for high-vacuum operation. Three ion pumps with high conductance manifolds and two titanium sublimation pumps are used to differentially evacuate the column. All vacuum-to-atmosphere seals are formed by using copper or Viton-A elastomer gaskets; no vacuum grease has been used in the system. Control feedthroughs have been replaced with dynamic bellows seals of the high-vacuum type, thus eliminating all O-rings in these components. Details of the pumping system and microscope modifications will be published elsewhere.
The Application of Ultra-Thin Sectioning Techniques to Non-Biological Samples
Authors: Oster C. F.
Published: June 2020

Although ultra-thin sectioning techniques are widely used in the biological sciences, their applications are somewhat less popular but very useful in industrial applications. This presentation will review several specific applications where ultra-thin sectioning techniques have proven invaluable.

The preparation of samples for sectioning usually involves embedding in an epoxy resin. Araldite 6005 Resin and Hardener are mixed so that the hardness of the embedding medium matches that of the sample to reduce any distortion of the sample during the sectioning process. No dehydration series are needed to prepare our usual samples for embedding, but some types require hardening and staining steps. The embedded samples are sectioned with either a prototype of a Porter-Blum Microtome or an LKB Ultrotome III. Both instruments are equipped with diamond knives.

In the study of photographic film, the distribution of the developed silver particles through the layer is important to the image tone and/or scattering power. Also, the morphology of the developed silver is an important factor, and cross sections will show this structure.
High Resolution Replication of Metallic Microcrystals
Authors: Bottoms W. R. , Morriss R. H.
Published: June 2020

Bradley's well known direct carbon replication technique with Pt-C shadowing offers the best resolution of any method currently in use. In the present study variations of this technique were applied to a system of gold microcrystals in an effort to obtain replicas of the highest possible resolution. Crystals with diameter on the order of 1000Å and thickness ∼100 Å have been examined for surface defects which might effect the growth process. This requires replication with higher resolution than is normally obtained.

The basic technique consists of evaporating a suspension of the particles onto a clean glass slide, depositing 100-200 angstroms of carbon by vacuum evaporation, floating the carbon film on a solvent to remove the particles, and mounting the replica on support grids for shadowing. The factors limiting the resolution of the replica are:

The accuracy in the reproduction of the surface topography by the carbon film.

“Pile-up” effects due to the physical thickness of the carbon and Pt-C in the shadowing direction.

Contamination of the specimen and replica surfaces by a layer of hydrocarbons.

Granularity of the shadowing material.
The Materials Analysis Company Model 700 Scanning Electron Microscope
Authors: Macres V.G. , Preston O. , Yew N.C. , Buchanan R.
Published: June 2020

The Model 700 scanning electron microscope is a high resolution instrument which incorporates the same basic modular concept that has proven so satisfactory in the Materials Analysis Company Model 400 x-ray microprobe and its latest development, the Model 400S. The instrument described here is the basic building block to which accessories such as additional display tubes, special specimen holders, etc., can be easily added.

The electron-optical column consists of a triode electron gun, double electromagnetic condenser lens, and objective lens. A .004″ tungsten hairpin filament is used as the electron source, and the filament to grid spacing is externally adjustable during operation to optimize gun performance for all operating conditions. The double condenser system is unitized and uses a single energizing coil. An adjustable multiple aperture holder is provided between the double condenser lens system and the objective lens, which serves to define the convergence angle of the probe in the specimen plane.
High Resolution Scanning Electron Microscope Using Lathanum Hexaboride Cathode Electron Gun
Authors: Broers A. N.
Published: June 2020

A new scanning electron microscope has been built which uses a lanthanum hexaboride cathode electron gun. The microscope has three magnetic lenses which are prealigned in the electron optical column to better than 20 micron. The final lens has a design spherical aberration of 1.8 cm for a 6 mm working distance. The pole-pieces of the final lens have been machined round within 0.25 micron and are aligned with respect to the axis of the lens to better than 10 micron. The electron gun which has been described previously uses a lanthanum hexaboride rod cathode. The cathode has approximately two orders of magnitude longer life than a 5 mil tungsten hairpin and is capable of producing an electron beam with a maximum brightness of 5.6 x 105 A/cm2 /ster at 12 KV. This brightness is approximately five times greater than that produced by a 5 mil tungsten hairpin under similar conditions.
Transmission Electron Cinephotography of Aℓ Films During Passage of Electrical Current
Authors: Blech I. A. , Meieran E. S.
Published: June 2020

Mass transport has been observed in metals conducting direct current. The atom flux can be toward either the anode or the cathode, depending on the conductor material. For Aℓ wires, it was found that the Aℓ atoms migrated from the cathode to the anode, apparently due to momentum transfer from the electrons to the atoms.

This mass transport was directly observed during current passage through Aℓ strips by transmission electron microscopy, using a specially constructed sample holder for the Hitachi HU-11 electron microscope and an appropriate sample. The samples were made by evaporating a thin Aℓ film onto an 0.010 inch thick Si wafer coated with 1000Å of SiO2- The Aℓ film was etched into the pattern shown schematically in Fig. 1 by normal photoresist techniques.
Epitaxial Copper Films Evaporated in Ultra-High Vacuum
Authors: Shimaoka G. , Lane J. W.
Published: June 2020

Recent electron microscopy and diffraction studies of vacuum-deposited films have demonstrated the importance of temperature and surface condition of substrate in determining film structure and growth. Many interesting results of thin epitaxial films of face-centered cubic metals such as gold and silver have been reported. But, relatively few studies of copper have been made. The purpose of this study is to investigate structure and epitaxy of copper thin films evaporated onto various single-crystal substrates in an ultra-high vacuum.

High purity copper was evaporated onto freshly cleaved (0001)MoS2, (100)NaC1, (001)mica and (11)CaF2 surfaces heated at temperatures between ∼25° and 200°C in a vacuum of ∼10-8 Torr. Average thickness of deposited films was about 90 Å. Deposition rate was about 0.4 Å/sec. The films were studied by reflection electron diffraction and transmission electron microscopy. Oxidation of copper films during preparation for electron microscopy and diffraction observation was minimized by deposition of thin layer of amorphous carbon upon freshly formed copper films.
Structure of CdS Films Deposited on Single-Crystal Substrates
Authors: Shimaoka G.
Published: June 2020

Recent X-ray or electron diffraction studies of CdS films vacuum-deposited on single-crystal substrates, such as mica, rock salt, etc., have demonstrated a marked effect of the substrate on the structure and orientation of the deposited films, particularly Escoffery has reported that cubic CdS (zinc-blende type) could be produced on molybdenum foil heated at 175°C. The purpose of this study is to investigate structure and orientation of thin CdS films evaporated onto various single-crystal substrates having hexagonal or cubic structure as a function of substrate temperature and to find optimum epitaxial growth condition.

Single-crystal CdS (hexagonal, wurtzite type) was evaporated onto freshly cleaved (0001) MoS2, (111) CaF2 and (100) NaCl surfaces heated at various temperatures between ∼25° and 500°C in a vacuum of about 5 x 10-5 Torr. Average thickness of the deposited films was about 100Å. The rate of deposition was about 2Å/sec. The deposited films were examined by three different methods: a) reflection electron diffraction, b) high-resolution transmission electron diffraction and c) transmission electron microscopy and selected-area electron diffraction.
Etching of Polymers by Oxygen Plasma
Authors: Peck Virgil , Carter W. L.
Published: June 2020

Any electron microscopical study of the morphology of bulk polymers has throughout the years been hampered by the lack of any real ability to produce meaningful surface variations for replication. True etching of polymers should show crystalline and amorphous regions in some form of relief. The use of solvents, acids, organic vapors, and inert ion bombardment to etch samples has proved to be useful only in limited applications. Certainly many interpretations of these results are subject to question.

The recent use of a radiofrequency (R. F.) plasma of oxygen to degrade and remove organic material with only minor heating has opened a new possibility for etching polymers. However, rigid control of oxygen flow, time, current, and sample position are necessary in order to obtain reproducible results. The action is confined to surface layers; the molecular weight of the polymer residue after heavy etching is the same as the molecular weight of the polymer before attack, within the accuracy of measurement.