bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron Microscopy of the Hypertrophic Scar
Authors: Kischer C. W. , Linares H. , Dobrkowsky M. , Larson D. L.
Published: June 2020

Hypertrophic scarring frequently occurs during or after the healing of deep second degree or third degree burns or equivalent trauma to the body surface. Clinically, the scar begins as a generalized firming or hardening of the skin area with an increased reddening over that of normal skin. These conditions intensify rapidly. The scar elevates and begins contracting, sometimes resulting in serious deformities, grotesque appearance, and severe loss of function.

During development of the scar the reticular dermis undergoes an unusual reconstruction. The collagen fibers first become oriented into whorl-like arrangements, which most likely develop further into discrete nodules. The etiology of the hypertrophic scar is unknown. However, since nodular formation is so characteristic for the scar an examination of the nodule itself may suggest etiologic possibilities for the scar.
Pathology of Bone Cells in Pigs with Experimental Turbinate Osteoporosis (Atrophic Rhinitis)
Authors: Fetter A. W. , Capen C. C.
Published: June 2020

Atrophic rhinitis in swine is a disease of uncertain etiology in which infectious agents, hereditary predisposition, and metabolic disturbances have been reported to be of primary etiologic importance. It shares many similarities, both clinically and pathologically, with ozena in man. The disease is characterized by deformity and reduction in volume of the nasal turbinates. The fundamental cause for the localized lesion of bone in the nasal turbinates has not been established. Reduced osteogenesis, increased resorption related to inflammation of the nasal mucous membrane, and excessive resorption due to osteocytic osteolysis stimulated by hyperparathyroidism have been suggested as possible pathogenetic mechanisms.

The objectives of this investigation were to evaluate ultrastructurally bone cells in the nasal turbinates of pigs with experimentally induced atrophic rhinitis, and to compare these findings to those in control pigs of the same age and pigs with the naturally occurring disease, in order to define the fundamental lesion responsible for the progressive reduction in volume of the osseous core.
Permeability in the Blood-Brain Barrier in Monkeys Following Exposure to High Altitude
Authors: Demaree R.S. , Ackerman L.J. , Anderson D. L.
Published: June 2020

People who rapidly ascend to high terrestrial elevations may experience the “acute mountain sickness” syndrome. Speculation and limited evidence suggest that cerebral edema may play an important role in initiating and perpetuating this condition. We have recently demonstrated by electron microscopy that a mild cerebral edema develops in some Cebus apella monkeys rapidly transported to 14,110 feet. In the present study, Cebus apella monkeys were terminated at 1, 3, or 5 days after being shipped from sea level (160 feet) to 14,110 feet without acclimatization at intermediate altitudes.

Thorotrast was administered IV 30 minutes prior to termination by perfusion or guillotine. Cerebral cortex was fixed by either perfusion or immersion in glutaraldehyde, and postfixed in osmium tetroxide. Following fixation, the tissues were dehydrated in ascending concentrations of ethanol followed by propylene oxide and embedded in Epon 812. Ultrathin sections were either not stained or doubly stained with uranyl acetate and lead citrate.
Golgi Complex in Trophozoites of Entamoeba histolytica
Authors: Treviño Norberto , Feria-Velasco Alfredo
Published: June 2020

Several authors have contributed with various descriptions of Entamoeba histolytica at fine structural level. Many of them have mentioned that the trophozoites do not have some cell organelles such as mitochondria, centrioles and Golgi complex. Eaton et al. have reported a “Golgi-like” structure in some trophozoites of E. histolytica cultivated in T.T.Y. Crithidial medium. In our laboratory, during the course of ultrastructural and cytochemical work on trophozoites of Entamoeba histolytica cultivated in mixed, monoxenic and axenic media we have corroborated those findings. However, in experiments designed to study the action of some antiamebic drugs we have been able to observe important morphological changes in the cytoplasm of trophozoites.
Observations of Germinating Lychnis Alba Pollen
Authors: Crang Richard E. , Millay Michael A.
Published: June 2020

The exine surface of Lychnis alba pollen grains is ornamented with spines and pits (Fig. 1) that are variable both in size and number. No relationship appears to exist between the relative nature of these surface features as observed by means of scanning electron microscopy (SEM) and germination potentials of the pollen. The protrusion of cytoplasm at the apertures is a common phenomenon as the grains become hydrated when placed in liquid culture medium. As swelling of the apertures occurs, the aperturate opercula, or pore plates, may be lifted to the terminal surface but frequently are displaced to one side where they become embedded in the pollen tube wall (Fig.2). Although all apertures may protrude, only a single pollen tube will normally form from each grain. The composition of the opercula appear similar to the exine in transmission electron microscopy (TEM) preparations, but is less dense than the exine when observed in SEM preparations, as indicated by surface folds suggestive of a soft composition. There is no structural evidence that enzyme degradations of the exine at germination sites is required for emergence of the pollen tube, although such may be the case when pollen germinates on the style as indicated in SEM observations of Pharbitis nil pollen.
Resolution of Channels in the Exine by Translocation of Colloidal Iron
Authors: Rowley John R.
Published: June 2020

The morphology of the exine of many pollen grains, at the time of flowering, is such that one can suppose that transport of substances through the exine occurred during pollen development. Holes or channels, microscopic to submicroscopic, are described for a large number of grains. An inner part of the exine of Epilobium angustifolium L. and E. montanum L., which may be referred to as the endexine, has irregularly shaped channels early in pollen development although by microspore mitosis there is no indication of such channeling in chemically fixed material. The nucleus in microspores used in the experiment reported here was in prophase of microspore mitosis and the endexine, while lamellated in untreated grains, did not contain irregularly shaped channels. Untreated material from the same part of the inflorescence as iron treated stamens was examined following fixation with 0.1M glutaraldehyde in cacodylate-HCl buffer at pH 6.9 (315 milliosmoles) for 24 hrs, 4% formaldehyde in phosphate buffer at pH 7.2 (1,300 milliosmoles) for 12 hrs, 1% glutaraldehyde mixed with 0.1% osmium tetroxide for 20 min, osmium tetroxide in deionized water for 2 hrs and 1% glutaraldehyde mixed with 4% formaldehyde in 0.1M cacodylate-HCl buffer at pH 6.9 for two hrs.
The Occurrence of “A,” “C” and “Spoked” Virus Particles in Hamster Tumors
Authors: Saito H. , Uzman B. G.
Published: June 2020

Several passages of five different hamster tumor lines were surveyed by electron microscopy for the presence of virus particles. Four of these tumors originated and were serially transplanted in adult Syrian hamsters. One line was derived by implantation of cultured baby hamster kidney cells. In all 5 tumor lines examined, “spoked virus” particles, first described by Bernhard and Tournier, were observed. These particles (Fig. 1) have an outer diameter of 90-110 mµ with a central nucleoid of 40-50 mµ and are always found in cisternae of rough endoplasmic reticulum or within the outer nuclear envelope. They are easily distinguishable from the murine leukemia type C particles by the presence of characteristic electron-dense radial structures which emanate from the nucleoid. In the cell line which has been most extensively studied (H-Sul-1-SC), the number of particles per cell appeared to increase in later passages of the tumor. Tumor cells from this line were grown in culture and were found to carry the same particles. While the “spoked virus” has been found by many investigators in a variety of neoplastic hamster cells, it has not been observed in this laboratory in an extensive survey of human tumor cells serially transplanted in newborn hamsters.
Continuous Type C Virus Production in a Tissue Culture of Human Origin (Burkitt Lymphoma)
Authors: Priori Elizabeth S. , Dmochowski Leon , Myers Brooks , Wilbur Jordan R.
Published: June 2020

Electron microscopy of numerous tissue cultures derived from various types of human tumors revealed only occasional type C virus particles in tissue cultures of leukemia and lymphoma (Dmochowski, L., Fourteenth Annual Conf. on Cancer, Yearbook Medical Publ, Inc., 37, 1969) and of solid tumors such as osteosarcoma, giant cell tumors (Priori, E. S. et al., J. Nat. Cancer Inst., 1971, in press), and in rhabdomyosarcoma.

This report describes a monolayer tissue culture derived from pleural effusion cells of a patient with Burkitt lymphoma (American type) which continuously produces type C virus particles. The child expired 14 days after collection of the pleural effusion due to a generalized varicella infection. Varicella virus particles could not be found in the original pleural effusion cells nor in any of the tissue culture passages.
Lysosome-Like Bodies in the Hepatopancreas of Oniscus Ascellus
Authors: Roberts John W. , Witkus E. R.
Published: June 2020

The hepatopancreas of the Isopod, Oniscus ascellus is comprised of two pairs of blind-ending diverticula which empty into the straight-line digestive tract through the hepatopancreatic duct. The cells at the blind distal tip are unspecialized regenerative cells. Mitotic activity of the cells in this region pushes older cells proximally in the lobe. As this occurs, the cells differentiate into either secretory B-cells or absorptive S-cells. By making serial sections, it is possible to trace the differentiation of the regenerative cells into both cell types.

Lysosome-like bodies were observed within the secretory B-cells. These bodies were found to measure approximately 0.5 to 2.5 microns in diameter. These bodies also were observed to contain many membrane-figures (fig. 1).
Observations on the Nerve Cells and Chromaffin-Like Cells of the Sympathetic Ganglion in the Seminal Vesicle of the Rat
Authors: Scott E. B. , Hung K. S.
Published: June 2020

This report focuses on the ultrastructure of nerve cells and “chromaffin” cells of a peripheral sympathetic ganglion. the nerve cells occured singly, varying in size from 10-18μ. Each nerve cell was ensheathed by satellite cells, with and without intermingled non-myelinated fibres. The nucleus was round or oval; nuclear pores were rare; the chromatin was evenly distributed; a single nucleolus was eccentrically placed. Clusters of ribosomes, dispersed throughout the perikaryon, were densly aggregated around isolated cisternae of granular endoplasmic reticulum. Mitochondria were numerous and of variable size and form. An extensive Golgi complex occupied a perinuclear position and was composed of flat, parallel cisternae and associated vesicles.
Complex Carbohydrates Associated with the Tegument and Subtegument of the Developmental Stages of the Blood Fluke, Schistosoma Mansoni
Authors: Shannon W. Allen
Published: June 2020

Periodic acid-thiocarbohydrazide-osmium(PATCO) and periodic acid-chromic acid-silver methenamine (PACrAS) techniques are employed to visualize complex carbohydrates. The nature of the various inclusions observed in the tegument and subtegument and the acetabular gland inclusions is of particular interest.

In the sporocyst stage, glycogen (gl) is the most prominent PATCO-(Fig.1) and PACrAS-positive substance in the tegument or subtegument. The Ig type of inclusion gives a positive PATCO (Fig.1) or PACrAS reaction when found in the tegument but not when associated with glycogen deposits in the subtegument. In immature cercariae, the glycocalyx (g) as well as the postacetabular gland inclusions (PO) react strongly to the PATCO (Fig.2) and the PACrAS techniques. Both reactions result in some variation in intensity in the postacetabular gland inclusions which may reflect the state of formation or condensation of the ingredients. The preacetabular gland inclusions (PR) are not reactive and disintegrate somewhat under the conditions of the experiments (Fig.2). I1 and I2 types of inclusions in the tegument react intensely (Fig.2). In addition, I3 inclusions in the subtegument exhibit what appears to be a positive reaction with the PACrAS technique.
Dark Field Procedures in Electron Microscopy of Particulate Biological Material
Authors: de Harven E. , Leonard K. R. , Kleinschmidt A. K.
Published: June 2020

The dark field image of a specimen is obtained by allowing elastically scattered electrons to pass along the optic axis of the objective lens. Most of the inelastically scattered and the undeflected electrons are eliminated by various procedures, three of which have been found practical in conventional transmission electron microscopes. These three procedures are based on the use of: i) “beam stop” dark field apertures positioned in the back focal plane of the objective lens, as described by Thon; ii) electron beam tilted mechanically, or by a deflecting magnetic coil system between the condenser lens and the object; iii) a “cone mantle” illumination of the object obtained by an annular condenser aperture of appropriate dimension. Our observations have been made with Siemens Elmiskop 1A and 101 electron microscopes, equipped with pointed cathodes (single crystal or lancet-shaped). All samples were supported by ultrathin (2 to 3 nm) carbon films. They included: (a) various viral DNA-cytochrome c monolayers, (b) horse spleen ferritin, (c) B. Subtilis SP 50 bacteriophages, and (d) 50 S E. Coli ribosomal particles. Samples (c) and (d) were stained with uranyl ions.
Optical Shadowing of Macromolecules
Authors: Haydon Glen B. , Hill Bruce C. , Lemons Ross A.
Published: June 2020

Dramatic 3-D effects resembling that seen in the scanning microscope are possible with the conventional transmission electron microscope employing its full resolution. The effect is especially useful in the study of macromolecules spread upon a substrate. Three examples illustrate the potential:

(1) A strand across a hole in a clean parlodion-carbon film, Figure 1,

(2) A typical shadowed preparation of DNA, Figure 2,

(3) A preparation of ferritin, Figure 3

Although it is premature to draw definitive interpretations from such micrographs, some speculation is possible. Since the optically shadowed image of fresh carbon films shows a very smpoth surface as seen in Figure 1, the rough appearance seen in Figures 2 and 3 must be related to the material which is placed upon the substrate. A part of the appearance probably results from aggregated protein material distributed over the surface. The alteration of such protein structures by the electron beam is not understood. Sufficient exposure to image a molecule might be expected to cause significant molecular rearrangement or dissociation (Breedlove & Trammell, Science 170:1310, 1970). Thus, the rough appearance is that of the organic residue altered to a more stable form in the beam. In the ferritin preparation, Figure 3, the iron cores appear upon a rough surface which is presumably composed of denatured proteins further modified by the electron beam.
High Resolution Stereography of Complementary Freeze-Fracture Replicas Reveals the Presence of Depressions Opposite Membrane Associated Particles of Split Membranes
Authors: Steere Russell L.
Published: June 2020

Complementary replicas have revealed the fact that the two common faces observed in electron micrographs of freeze-fracture and freeze-etch specimens are complementary to each other and are thus the new faces of a split membrane rather than the original inner and outer surfaces (1, 2 and personal observations). The big question raised by published electron micrographs is why do we not see depressions in the complementary face opposite membrane-associated particles? Reports have appeared indicating that some depressions do appear but complementarity on such a fine scale has yet to be shown.

Dog cardiac muscle was perfused with glutaraldehyde, washed in distilled water, then transferred to 30% glycerol (material furnished by Dr. Joaquim Sommer, Duke Univ., and VA Hospital, Durham, N.C.). Small strips were freeze-fractured in a Denton Vacuum DFE-2 Freeze-Etch Unit with complementary replica tooling. Replicas were cleaned in chromic acid cleaning solution, then washed in 4 changes of distilled water and mounted on opposite sides of the center wire of a Formvar-coated grid.
Biological Applications of the Scanning Transmitted Electron Microscope
Authors: Matsuo Tatsuya , Suzuki Mikio
Published: June 2020

Recently, very thick section of biological specimens have been observed by using super high voltage electron microscope to obtain a three dimensional model of a specimen.

However, the thicker the section, the more difficult the penetration of staining solution into the depth of thick section. So, it is doutful whether the stain solution fully penetrated into the thick section. This paper reports an observation of various thick unstained sections using scanning transmitted electron microscope(STEM) and conventional electron microscope(CEM).

The observed specimen is mice liver cells. The tissue was fixed in cold 1% phosphate-buffered osmium tetroxide solution for 2 hours. After fixation, the tissue was dehydrated in a graded series of ethanols and then embedded in Epon 812. The 500 Å, 5,000 Å and 1μ thick sections were cut, not stained with uranyle and lead, and then examined with STEM and GEM operated at accelerating voltage 80 kV.
Modification for Electron Miscroscopy of the Corbett Ammoniacal Silver Stain
Authors: Corbett Robert L.
Published: June 2020

The ammoniacal silver stain for light microscopy of plastic embedded sections has been adapted for use in electron microscopy. Since the silver will stain even very thin sections, i.e., silver and gold for light microscopy, and silver deposits are sufficiently electron dense to be seen in the electron microscope, the results are very useful for correlating light and electron microscopy. Compared to the conventional stains for electron microscopy which usually take over one-half hour, the silver procedure can be done in five minutes or less and thus provides a quick look at sections This stain has more contrast, so it is especially good for low power electron microscopy. The ability of the silver to stain very thin sections enables a correlation between light and electron microscopy in three ways. First, thin sections can be stained with silver on a glass slide and compared with immediately adjacent thin sections on grids stained the usual way for electron microscopy.
The Use of Styrenes as Embedding Media for Electron Microscopy
Authors: De-Lamater Edward D. , Johnson Eric , Schoen Thad , Whitaker Cecil
Published: June 2020

Monomeric styrenes are demonstrated as excellent embedding media for electron microscopy. Monomeric styrene has extremely low viscosity and low surface tension (less than 1) affording extremely rapid penetration into the specimen. Spurr's Medium based on ERL-4206 (J.Ultra. Research 26, 31-43, 1969) is viscous, requiring gradual infiltration with increasing concentrations. Styrenes are soluble in alcohol and acetone thus fitting well into the usual dehydration procedures. Infiltration with styrene may be done directly following complete dehydration without dilution.

Monomeric styrenes are usually inhibited from polymerization by a catechol, in this case, tertiary butyl catechol. Styrene polymerization is activated by Methyl Ethyl Ketone peroxide, a liquid, and probably acts by overcoming the inhibition of the catechol, acting as a source of free radical initiation.

Polymerization is carried out either by a temperature of 60°C. or under ultraviolet light with wave lengths of 3400-4000 Engstroms; polymerization stops on removal from the ultraviolet light or heat and is therefore controlled by the length of exposure.
Scanning and Transmission Electron Microscopic Evaluation of Parathyroid Glands
Authors: Capen C. C. , Fetter A. W.
Published: June 2020

Parathyroid glands of normal animals were composed of groups of chief cells surrounded by a continuous basement membrane and fine collagen fibers (Fig. 1). Scanning electron microscopy demonstrated chief cells to be arranged into spheroidal or ovoid groups interconnected by collagen fibers (Fig. 2). Tubular profiles of capillaries were intimately applied to the surface of the spheres.

Present evidence indicates that the parathyroids contain a single type of secretory cell concerned with the elaboration of one hormone. Chief cells interpreted to be in an inactive stage of the secretory cycle predominated in most species. Organelles other than mitochondria were poorly developed and numerous lipid bodies were present. Active chief cells occurred less frequently and had well developed organelles concerned with protein synthesis and packaging of secretory products.

Secretory granules were readily demonstrated within chief cells. They were more numerous in active than inactive chief cells. The granules were small, ranging from 100-300 μ in greatest diameter, surrounded by a closely applied limiting membrane, and composed of fine dense particles. The granules moved peripherally and the limiting membrane fused with the plasma membrane of the cell.
Fine Structure of the Ultimobranchial Gland in the Chick
Authors: Chan A. S.
Published: June 2020

Although the ultimobranchial gland of the chick has been shown to contain large amounts of calcitonin relatively few reports have been published on its fine structure. In the present study, the ultrastructure of the chick ultimobranchial gland, with emphasis on the cells which appear to be the producers of the hormone, will be examined. Ultimobranchial glands were obtained from twenty 2-week-old chicks and fixed in glutaraldehyde followed by osmium tetroxide.

The gland is composed of aggregate of cords and clusters of cells interspersed with variable numbers of cyst-like cavities. Two parenchymal cell types, namely, light and dark cells can be recognized (Figs. 1,2,3). Epithelial cells, varying from columnar to cuboidal, line the cavities of the cysts.

Light cells form the majority of the cell types (Fig. 1). The cytoplasm is characterized by the presence of membrane-limited secretory granules, measuring from 100 to 350 mμ in diameter. The contents of the secretory granules vary in electron density from moderate to extreme (Figs. 1,2). Secretory granules are distributed randomly in the cytoplasm although some are lined near the cell membrane.
Cytoplasmic Structures in Insect Granular Hemocytes
Authors: Hagopian M.
Published: June 2020

Femoral segments from the metathoracic leg of the freshly molted cockroach nymph, Leucophaea maderae, were removed and were prepared for electron microscopy. The femoral cuticle with underlying epidermal cells encloses muscle, nerves, tracheae, tracheoles, and the hemocoel. In the insect open circulatory system the hemocoel contains hemolymph and hemocytes. Some of the known functions of insect hemocytes are phagocytosis, encapsulation, melanization, Wound healing, coagulation and possible transformation into other tissues. Previous studies of the agranular and granular hemocytes however lack the fine structure that is helpful in determining cellular function.

The several different types of granular hemocytes have a general elliptical appearance, large nucleus, and prominent cytoplasmic granules. The most abundant type of granules are the membrane-bounded, roughly spherical, opaque inclusions which average about 1 to 2μ in diameter. These dense inclusions resemble vertebrate melanosomes. Other granules with an organized substructure are reminiscent of the vertebrate premelanosomes (Figs. 1, 2). In certain planes of section the premelanosome-like granules reveal that the internal configurations are microtubules which measure about 250A in diameter.
Fertilization Membranes and Sea Urchin Embryos Studied by Scanning Electron Microscopy
Authors: Humphreys Walter J. , Lindsay David T.
Published: June 2020

Scanning electron microscopy (SEM) of specimens freeze-dried after fixation in Parducz fixative and ultrathin sections of the sea urchin,Strongylocentrotus purpuratusshow that the egg is covered by many papillae about 0.25μ in diameter and 0.5μ long (Fig. 1a). When the vitelline layer lifts away from the surface of the egg at the time of fertilization it has many uniformly spaced protrusions that persist as prominent and consistent structural features of the fertilization membrane, which forms when material from ruptured cortical granules is added to the inner surface of the raised vitelline membrane. Dimensions of the protrusions, their spacing on the membrane, and their projection in a direction outward from the egg (Fig. 1b) suggests that they originate when the vitelline layer lifts away from the egg surface in the form of a somewhat distorted and expanded replica of the papillae-bearing surface of the unfertilized egg.
Isolated Plasma Membranes of Sea Urchin Eggs
Authors: Inoue S. , Preddie E. C. , Guerrier P.
Published: June 2020

From electron microscope studies of thin sections the sea urchin egg is known to be surrounded by the peripheral membrane system which is made up of the outer coat (vitelline membrane), which elevates from an egg surface after fertilization and becomes a part of the fertilization membrane, and the plasma membrane. In these experiments an effort has been made to isolate plasma membranes of sea urchin eggs and these isolated membranes were observed in the electron microscope.

The vitelline membrane of the eggs from the sea urchin Strongylocentrotus purpuratus was at first digested away by the treatment with 0.02% trypsin in 0.01 M Tris-HCl buffer (pH 8.0) for 5 minutes at 28°C. The plasma membranes were then isolated according to the method of Song et al. which was used for the isolation of rat liver plasma membranes. The vitelline membrane-free eggs were gently homogenized in 10-3 M NaHC03 (pH 7.5) and freed membranes were collected by centrifugation over a discontinuous sucrose gradient preparation.
Modification of Pyrrolizidine Toxicity by Altering Hepatic Microsomes
Authors: Allen J. R. , Carstens L. A.
Published: June 2020

The pyrrolizidine alkaloid, monocrotaline is capable of producing necrosis, megalocytosis, carcinogenesis and veno-occlusive disease of the liver. Kidney lesions include glomerular hyalinization, necrosis of afferent arterioles and disruption of the arterial walls. Capillary occlusion by fibrin and platelet thrombi and hypertrophy of the smooth muscle cells in the small muscular arteries of the lung precede the development of pulmonary hypertension. The means by which this alkaloid produces the above mentioned lesions has not been clarified. Butler et. al. have reported that pyrrole metabolites are capable of causing pulmonary and hepatic lesions similar to monocrotaline. In the presently reported study it is shown that the enhancement (phenobarbital) or inhibition (chloramphenicol) of microsomal enzymes is instrumental in determining the magnitude of the lesions and the survival rate of animals.

Male, Sprague Dawley rats were divided into 6 groups and received monocrotaline, phenobarbital, phenobarbital-monocrotaline, chloramphenicol, chloramphenicol-monocrotaline, and physiological saline (Table 1). Rate of gain was reduced and 50% of the animals in the phenobarbital-monocrotaline group expired within 14 days following the injection of monocrotaline.
Experimental Amyloidosis Induced by Immune Complex
Authors: Kawaoi A.
Published: June 2020

Numbers of immunological approach have been made to the amyloidosis through the variety of predisposing human diseases and the experimentally induced animals by the greater number of agents. The results suggest an important role of impaired immunity involving both humoral and cell-mediated aspects.

Recently the author has succeeded in producing amyloidosis in the rabbits and mice by the injections of immune complex of heat denatured DNA.

The aim of this report is to demonstrate the details of the ultrastructure of the amyloidosis induced by heterologous insoluble immune complex. Eleven of twelve mice, dd strain, subcutaneously injected twice a week with Freund's complete adjuvant and four of seven animals intraperitonially injected developed systemic amyloidosis two months later from the initial injections. The spleens were electron microscopically observed.
Electron Microprobe Analysis of Returned Lunar Samples
Authors: Keil Klaus
Published: June 2020

The principle of the electron microprobe analyzer is explained and the special advantages of the technique in the study of returned lunar samples is discussed. Emphasis is given to non-destructive in-situ quantitative elemental analysis of micron-sized volumes. Results of electron microprobe analyses of rocks, and fines returned to Earth by the Apollo 11 and 12 missions are presented. Data that have significance to hypotheses on the origin and history of the lunar surface in the vicinity of the Apollo 11 and 12 landing sites and the Moon as a whole are given. Evidence is presented for differentiation of the Moon on a large scale, internal melting, absence of hydrous phases, lower oxygen fugacities as compared to terrestrial rocks, impact origin of fines and breccias, and high age near 4.5 billion years. Existing models for the origin of the Moon are discussed in the light of the data obtained by electron microprobe analysis, and it is concluded that neither the fission model nor the classical chondritic model can adequately explain the origin of the Moon.
Microcraters in Lunar Samples
Authors: McKay David S.
Published: June 2020

Introduction. Samples of rock, mineral, and glass fragments returned by Apollo 11 and 12 contain a variety of microcraters which were formed by the impacts of small projectiles. The craters are especially prominent in some of the small glass spherules and related forms.

Crater types. It is possible to classify these microcraters on the basis of morphology as seen by the scanning electron microscope. Type I microcraters (Figure 1) show the following characteristics:

A. A glassy central area is present which has been melted by the impact. This glass is primarily material from the target but may also contain melted projectile material. The central area is normally very smooth and may or may not have a smooth raised lip.
Computer Enhancement of Electron Micrographs
Authors: Nathan Robert
Published: June 2020

The digital computer with associated video camera scanner equipment can be used in conjunction with the microscope's best performance to give improved and ultimately perhaps atomic resolution. Examples of computer application emphasize space photography where the computer enhancement methods originated. The following operations evolved as a result of working with television images: geometric correction, photometric correction, random noise removal, periodic noise removal, scan-line noise removal, and modulation transfer function ,(MTF) correction (compensation for attenuation of spatial high-frequency components).

Other examples include the enhancement of a micrograph of negatively stained catalase, a micrograph of some microtubules and a video recording of indathrene olive. In a crystal, because of its periodicity, improvement can be obtained in the signal to noise ratio by translating and superimposing the image upon itself.
Computer Synthesis and Filtration of Electron Micrographs of Simple Molecular Objects
Authors: Welton T. A.
Published: June 2020

A flexible computer program for the IBM 360/91 gives us the capability of synthesizing fairly realistic electron micrographs in the form of computerproduced transparencies which have all of the essential features of actual electron-exposed emulsions. We can control the assumed properties of the illuminating electron beam, the contents of the object plane, the electron optical properties of the objective and magnification system, and the properties of the detector system (emulsion). Statistical error (noise) can be realistically introduced. The resulting transparencies give very striking visual evidence concerning the quality of the information obtainable about simple molecular (DNA) samples under various interesting assumptions.

As presently operating, we can conveniently place up to three complete periods of the double helical DNA structure (100.8 Å) in the object plane. The object is assumed to repeat indefinitely with a rectangular unit cell, so that a discrete Fourier series can be used. The Fourier coefficients of the image wave (just after sample passage) are computed from the known atomic coordinates.
Stereoscopic Analysis of Dislocation Distributions from Electron Micrographs
Authors: Thomas L. E. , Cuddy L. J.
Published: June 2020

The use of stereo pairs of electron micrographs for quantitative analysis of defect structures offers several advantages over methods which use single micrographs: stereoscopic viewing aids in comprehending complicated 3-dimensional structure. Defect densities can be measured locally, i.e. as a function of depth in the specimen rather than as an average over the foil thickness. The depth definition afforded by 3-dimensional viewing largely eliminates problems of image overlap. The depth dimension can be measured from the micrographs. In this paper, stereo techniques for analyzing dislocation distributions will be discussed along with results obtained using high voltage electron micrographs of very thick foils.

Although the practice of electron stereomicroscopy with diffraction contrast images is not yet widespread, the technique is not difficult. Two different views of the same specimen detail are obtained by tilting the specimen between exposures. With diffraction contrast, the operating reflection and Bragg deviation must be kept the same so that any differences in the position and appearance of the defect images is due to the change in viewpoint.
Phase Contrast in Electron Microscopy
Authors: Johnson H. M. , Parsons D. F.
Published: June 2020

Phase shifting of scattered or non-scattered waves into antiphase with respect to each other has provided the most advantageous optical contrasting technique for light microscopy. Analogously, attempts have been made in electron microscopy to achieve phase contrast, both in-focus and out-of-focus. Results have been complicated by lens aberrations, power supply instabilities, interpretation of defocused images and, in the case of lattice images, by the question of the actual imaging mode.

Defocus contrast has been further complicated by lateral displacement of dark field images from the corresponding bright field image as commonly observed with inorganic crystals (e.g. MgO). By means of image plane detectors (Fig. 1) the defocus contrast variation of polystyrene latex spheres (P.S.L.) (Fig. 2) has been related to the lateral shift of dark field images arising from carbon-carbon nearest neighbor scattering. Lateral displacement arises from defocusing and from spherical aberration at focus (resulting in the variation of in-focus contrast for different microscopes used without an objective aperture).
Effects of Reserpine on Abdominal Paraganglia at the Fine Structural Level
Authors: Mascorro J.A. , Yates R. D.
Published: June 2020

Past investigations with the electron microscope have established the presence of two cell types in the abdominal paraganglia. Type I (glomus or chief) cells exhibit numerous cytoplasmic granules similar to the catecholamine containing ones of the adrenal medulla whereas Type II (sustentacular or supporting) cells lack such granules and send thin cytoplasmic processes partially or completely around clusters of Type I cells. Mascorro and Yates speculated that the granules of Type I cells might contain catecholamines. The present research was undertaken to determine if the amine depleting drug reserpine affected the fine structure of the cytoplasmic granules.

Eight white mice 10-18 days old were used for these experiments. Three of the animals received two subcutaneous injections of reserpine (2.5 mg/ kg) and. were sacrificed 48 hours after the onset of treatment. All animals were prepared for light and electron microscopy by perfusion with 2% glutaraldehyde in 0.1 M phosphate buffer followed by additional fixation in 1% osmic acid.
Ultra-structural Changes Induced in the Heart by In-vitro Perfusion
Authors: Schowengerdt C. G. , Basom C. R. , Wolf G. L.
Published: June 2020

Veterans Administration Hospital, Cincinnati, Ohio 45219 Departments of Surgery, Anatomy, and Laboratory Animal Medicine, University of Cincinnati, College of Medicine, Cincinnati, Ohio 45219

Dilute blood or plasma was used to perfuse mongrel dog hearts for 20-27 hours. The hearts were maintained with a Bramson membrane oxygenator at a pO2 of 200-250 mm.Hg and a pCO2 of 28.2-42.0 mm.Hg on a Belzer-Truman pump at 20-52 pulsations per minute. Warm ischemia time with excision of the heart averaged 6.6 minutes. The perfusate pressure was an average of 70/30 mm.Hg (systolic/diastolic) at a temperature of 12 to 20 degrees C. Of the various factors tested for functional preservation, a warm ischemia time of less than 20 minutes, a perfusate temperature of 12 to 15 degrees C., and a pressure of more than 40/15 mm.Hg were found to be most essential for preservation of functional viability. Functional viability was determined by the capacity of the heart to sustain rhythmic co-ordinated contractions following defibrillation.
Subcellular Elemental Analysis With the Abalytiual Electron Microscope
Authors: Chandler J.A. , Chou C.K.
Published: June 2020

Water-borne copper-chrome-arsenate preservatives(CCA) are now recognised throughout the world as the most effective broad-spectrum preservatives and are extensively used today for a wider range of purposes than any other preservative type. The mode of action of this preservative against decaying fungi, however, is little known and this paper reports investigations into an understanding of the process of treatment. The combination of transmission electron microscopy and x-ray microanalysis has for the first time allowed an accurate location for analysis of the consistuent elements in this preservative when applied to wood.
Biochemistry and Morphology of Fragmented Sarcoplasmic Reticulum
Authors: Peter J. B. , Fiehn W. , Dunn Robert F.
Published: June 2020

The function of the sarcoplasmic reticulum (SR) is well defined, but much confusion exists about the role of the SR in the contraction-relaxation cycle of slow-twitch muscles. Fragmented SR (FSR) was isolated from different guinea pig muscles. The muscles were classified as fast-twitch-red, fast-twitch-white or slow-twitch-intermediate according to their contractionrelaxation times and the histochemical characteristics of the component fibers.

The kinetics of calcium accumulation showed no difference between FSR from fast-twitch-red or fast-twitch-white muscles, and the yield of FSR (expressed as mg vesicle protein per gram of muscle) was the same. By contrast the amount of FSR obtained per gram of slow-twitch-intermediate muscle was only half as high. Likewise, the maximal amount of calcium that could be stored in the presence of oxalate by FSR from slow-twitch-intermediate muscles was only half that of FSR from fast-twitch muscles.
Preliminary Ultrastructural Evaluation of Uterine Leiomyomata
Authors: Scott J. R. , Roberts D. K.
Published: June 2020

Leiomyomata are benign uterine tumors composed of smooth muscle cells and varying amounts of connective tissue. The tumor occurs in approximately 10% of all women with a greater frequency in Negro women. The reasons for growth and development of these tumors are yet unknown. Meyer and DeSnoo suggest that the tumors originate in cell rests or genitoblasts and, under estrogen stimulation, multiply to form the tumor. Witherspoon suggests an ovary-leiomyoma relationship, in which prolonged high estrogen levels are due to cystic change in the ovary secondary to pelvic inflammatory disease. Others have demonstrated development of leiomyomata in animal studies. Anderson proposes that development of the tumor stems from an undetermined connective tissue cell of either the myometrium or its blood vessels.
Formation and Structure of Casein Micelles in Lactating Mammary Tissue
Authors: Carroll Robert J. , Thompson Marvin P. , Farrell Harold M.
Published: June 2020

Milk is an unusually stable colloidal system; the stability of this system is due primarily to the formation of micelles by the major milk proteins, the caseins. Numerous models for the structure of casein micelles have been proposed; these models have been formulated on the basis of in vitro studies. Synthetic casein micelles (i.e., those formed by mixing the purified αsl- and k-caseins with Ca2+ in appropriate ratios) are dissimilar to those from freshly-drawn milks in (i) size distribution, (ii) ratio of Ca/P, and (iii) solvation (g. water/g. protein). Evidently, in vivo organization of the caseins into the micellar form occurs in-a manner which is not identical to the in vitro mode of formation.
Morphological Maturation in Myeloproliferative Virus
Authors: James Arnold Wm. , Soule Herbert D. , Northup N. E.
Published: June 2020

Myeloproliferative virus (MPV) grows abundantly with high virulence in a stable cell line, MCF-6 and well in short-term BALB/c mouse embryo tissue culture infected from MCF-6. MPV was partially purified from culture supernatant by ultracentrifugation, fixed in buffered 3% glutaraldehyde followed with buffered 1% OSO4, embedded in Epon, sectioned and stained with lead and uranium. Cells from MCF-6, embryo cultures, and leukemic mice infected with cell-free MCF-6 supernatant were prepared similarly, or according to Hirsch and Fedorko.

All preparations contain MPV profiles resembling the C particles found associated with murine leukemias, avian leukoses, and Rous sarcoma. MPV buds from the outer surface (Fig.2) or, rarely, into cytoplasmic vesicles of the host cell and retains the empty-centered, concentric form commonly considered to be that of immature C particles until at least a short time before separation.
Electron Autoradiography of Adenovlrus Infected Cells
Authors: Yamamoto T. , Shahrabadi M.S.
Published: June 2020

The sequential morphological alterations in dog kidney cells infected with a canine adenovirus has previously been shown (3) to produce several intranuclear inclusions: (a) early DNA containing inclusions which form ringshaped structures and rapidly expand to form a large virus synthesizing mass; (b) dark staining spherical inclusions; (c) light staining inclusions: and (d) the virus aggregates which at later times, form crystals (Fig. 1). This report is an analysis of the nature and function of these inclusions with respect to the replicating virus using specific enzyme digestion and autoradiographic techniques.
The Initial Stages of Lymphocystis Virus Infection in Fish
Authors: McCoy D. D. , Edwards M. R. , Walker R.
Published: June 2020

The lymphocystis disease of fish is characterized by large wart-like growths on the skin and fins. These tumors are not neoplastic and result from an enormous enlargement of individual connective tissue cells. These cells, transformed by a large icosahedral DNA virus (ca. 200 nm), which replicates in the cytoplasm, are typically surrounded by a large PAS-positive hyaline capsule, and have a proportionately enlarged nucleus with one or more enlarged nucleoli and basophilic Feulgen-positive inclusions in the cytoplasm.
Freeze Etching of Vaccinia Virus Infected Cells
Authors: Easterbrook K.B. , Rozee K.R.
Published: June 2020

Recently the introduction of the technique of freeze - etching has permitted the reexamination of well known virus cell systems under conditions which not only preserve the ultrastructural details of specimens in achemically and physically unaltered state but also portray the topographical features of such details. Results obtained with myxovirus (1) and reovirus (2) have confirmed the potential of the technique for investigation of such systems.
A Comparison of Direct and Indirect Ferritin-Tagging Techniques
Authors: Sydney S. Breese
Published: June 2020

Direct ferritin-tagging techniques have been used on a number of virus systems in the past 4-5 years. More recently, indirect systems have been developed which reduce the number of conjugations which have to be made before experimental work can be started. In this report, examples will be shown of the application of both direct and indirect systems to virus antibody interactions of foot-and-mouth disease virus (FMDV), African swine fever virus (ASFV), and equine arteritis virus (EAV). These systems involve the use of guinea pig, swine, and equine sera and the associated globulins, respectively.
Cerebellar Granule Cells and Their Response to Radiation
Authors: de Estable-Puig Rosita F. , Estable-Puig Juan F.
Published: June 2020

The granular layer of the cerebellar cortex situated between the molecular and medullary layers is built up mainly of the perikarya of small interneurons, the granule cells intermingled with part of their own processes, mossy fiber terminals, fibers of passage and other less numerous intrinsic cells. Ultrastructurally they are characterized by a nucleus which occupies most of the cell body and a rim of cytoplasm. The nucleus exhibits some aggregates of chromatin and in some cells a nucleolus. In the cytoplasm very scarce organelles are observed (Fig.l). Their main synaptic connections are found, first, at the cerebellar glomerulus where granule dendrites are seen in postsynaptic position towards mossy fiber rosettes. Desmosomic attachments are observed between granule dendrites. Second, at the level of the molecular layer where parallel fiber terminals (ramifications of the peripheral axon ) are seen apposing Purkinje dendrite spines.
Three Dimensional Fourier Analysis of the Ribonucleoprotein Particle (Ribosome) Helix of Entamoeba Invadens
Authors: Lake James A. , Slayter Henry S.
Published: June 2020

Cysts of Entamoeba Invadens contain large ordered arrays of closely packed helices which absorb strongly in the ultraviolet. The helices consist of small, approximately spherical particles about 250Å in diameter. Several lines of evidence have indicated that they may be ribosomes. We shall refer to these particles as ribosomes in this paper.

DeRosier and Klug (1) have demonstrated that it is possible to reconstruct a three dimensional object from two dimensional projected images, i.e. micrographs, provided that sufficient views, of individual molecules are available. A single view (micrograph) of one ribosomal helix provides many views of individual ribosomes.
Polymerized Glutaraldehyde in the Fixation of Rat Lung Tissue
Authors: Wrench C. P.
Published: June 2020

Results of more than 70 tests on fixation of lung tissue in untreated Fischer and Osborne-Mendel rats, ages 2-5 months, have shown that a high concentration of aged, polymerized glutaraldehyde has better proteinbinding potential than fresh, or pure, fixative. The general practice in ultrastructural fixation is to maintain the concentration within a range of 2-5%. It has been found in this study that the effective concentration for clear ultrastructural detail in lung tissue is minimally 6%, and optimally 8%. Regular use is now made of 8% glutaraldehyde in 0.1M Sorensen's phosphate buffer for 2 hrs. in the cold. This is followed by thorough rinsing in buffer with added sucrose for 3 days, with daily changes of rinse, then postfixation with 1-2% OsO4 in 0.1M phosphate buffer. Dehydration, embedding, and staining methods are a matter of individual preference. All fixation is done by immersion.