bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructural Morphology of the Plastids in Ferocactus Latispinus (Haworth)
Authors: Rivera E. R. 
Published: June 2020

Mature plants of Ferocactus latispinus were divided into the apical meristem, cortical and cambial tissue, and young and mature photosynthetic tissue. Pieces 2x2x4 mm were fixed in 0.075 M PIPES buffered 5% glutaraldehyde and further treated for conventional transmission electron microscopy.The shoot meristematic cells contained dense cytoplasm with a few small vacuoles. All organelles expected to be found in unspecialized plant cells were present. The proplastids were 1-2 diameters larger than mitochondria. Some of these plastids were elongated and most contained small amounts of lipid globules in the stroma (Fig. 1). In addition, phytoferritin was sometimes found in the stroma. No starch was found in these organelles. The thylakoids were poorly developed, and when there were no inclusions in the stroma, proplastids were difficult to distinguish from mitochondria (Fig. 1).Cortical cells had very large, well-developed vacuoles. The organelles were restricted to the peripheral cytoplasm of the cell and to a few transvacuolar cytoplasmic strands.
Structured Matrices Associated With Adenovirus-Infected Swine Kidney Cells
Authors: Ritchie A. E. , Norman J. O. 
Published: June 2020

Fibrillar matrices (viroplasms) have been described for a number of viruses, mainly from studies of thin-sectioned infected cells. We have recently noted some structured matrices (observed in negatively-stained preparations) that were associated with swine kidney (SK) cells infected with an Adenovirus, infectious canine hepatitis. These cellular fragments may bear some special relationship to the process of viral maturation.Virus was propagated in primary swine kidney cell monolayers. Cell culture harvests were pooled and clarified by centrifugation at 1000 X g for 20 min at 4 C. The pelleted materials were dispersed in 5 to 10 times their volume of distilled water and sampled directly for phosphotungstate (PTA) negative staining: one drop of the suspension was diluted with ca. 15 drops of 1% PTA which contained a trace of bovine serum albumin (Fr. V); the sample was then applied to carbon-coated collodion-filmed grids with a Vaponefrin all-glass nebulizer (Brenner & Horne. Biochim. Biophys. Acta 34: 103 (1959). The process of nebulizing appeared to rupture those cells that reached the specimen grid permitting examination of cellular fragments in great variety.
An Ultrastructural Study of Pericytes
Authors: Murad T. M. , von Haam E. 
Published: June 2020

Pericytes are vascular satellites present around capillary blood vessels and small venules. They have been observed in almost every tissue of the body and are thought to be related to vascular smooth muscle cells. Morphologically pericytes have great similarity to vascular endothelial cells and also slightly resemble myoepithelial cells.The present study describes the ultrastructural morphology of pericytes in normal breast tissue and in benign tumor of the breast. The study showed that pericytes are ovoid or elongated cells separated from the endothelial cell of the capillary blood vessel by the basement membrane of endothelial cell. The nuclei of pericytes are often very distinctive. Although some are round, oval, or elongated, others show marked irregularity and infolding of the nuclear membrane. The cytoplasm shows mono-or bipolar extension in which the cytoplasmic organelles are located (Fig. 1). These cytoplasmic extensions embrace the capillary blood vessel incompletely. The plasma membrane exhibits multiple areas of focal condensation called hemidesmosomes (Fig. 2, arrow). A variable number of pinocytotic vesicles are frequently seen lining the outer plasma membrane. Normally pericytes are surrounded by a basement membrane which is found more consistently on the outer plasma membrane separating the pericytes from the stromal connective tissue.
The Fine Structure of Alginic Acid Components
Authors: Inoue S. , Tanaka Y. , Skoryna S.C. 
Published: June 2020

Sodium alginate, a brown seaweed polysaccharide, is capable of preventing intestinal absorption of radioactive strontium and its radiotoxicological importance is now well established. Alginic acid was found to be composed of 1,4-linked poly-L-guluronic acid and poly-D-mannuronic acid chains with some glycosidic linkages between these uronic acids.Polyguluronic and polymannuronic acid were prepared by acid hydrolysis of alginic acid from Laminaria hyperborea followed by fractionation of the partially degraded sodium alginate at pH 2.8. These components consist almost exclusively of a single uronic acid (polyguluronic acid: man/gul = 0.27; polymannuronic acid: man/gul = 10.7). Sodium polyguluronate inhibits absorption of radiostrontium more effectively than sodium polymannuronate.
Drug Induced Changes in Cell Organelles
Authors: Luse Sarah A. 
Published: June 2020

In the mid-nineteenth century Virchow revolutionized pathology by introduction of the concept of “cellular pathology”. Today, a century later, this term has increasing significance in health and disease. We now are in the beginning of a new era in pathology, one which might well be termed “organelle pathology” or “subcellular pathology”. The impact of lysosomal diseases on clinical medicine exemplifies this role of pathology of organelles in elucidation of disease today.Another aspect of cell organelles of prime importance is their pathologic alteration by drugs, toxins, hormones and malnutrition. The sensitivity of cell organelles to minute alterations in their environment offers an accurate evaluation of the site of action of drugs in the study of both function and toxicity. Examples of mitochondrial lesions include the effect of DDD on the adrenal cortex, riboflavin deficiency on liver cells, elevated blood ammonia on the neuron and some 8-aminoquinolines on myocardium.
Ultrastructure of Blood Vessels of the Area Pellucida of Control and X-irradiated Chick Embryos
Authors: Sanderson Margaret H. , Steamer S. Phyllis 
Published: June 2020

The chick embryo exposed to lethal doses of ionizing radiations develops a fatal circulatory failure within a few hours. This report describes the blood vessels of the area pellucida (a part of the extra-embryonic membranes of the chick embryo) and the effect of 250 kVp x-radiation upon them.Three-day chick embryos, x-irradiated in ovo with 1000-1200 R, were fixed 1-2 hours after exposure. The area pellucida is a multi-layered membrane consisting of ectoderm, somatic and splanchnic mesoderm, and endoderm (Fig. 1). The vascular system arises from the splanchnic mesoderm. The walls of small and medium-sized vessels are composed of endothelial cells, an occasional pericyte and processes of adjacent mesenchyme cells. Types of vessels cannot be distinguished at this stage of development; a basement membrane is seen only in isolated areas. The wall appears double or triple-layered, but the endothelium is frequently less than 0.1 micron thick (Fig. 2). Endothelial cells contain a large complement of polyribosomes, mitochondria, rough and smooth endoplasmic reticulum, a Golgi complex, pinocytotic vesicles and several kinds of inclusion bodies. The nucleus has a well-defined nucleolus.
Mitochondria in Cardiomyopathy: Alterations in Size, Number and Internal Structures
Authors: Hug George , Schubert William K. 
Published: June 2020

A white boy six months of age was hospitalized with respiratory distress and congestive heart failure. Control of the heart failure was achieved but marked cardiomegaly, moderate hepatomegaly, and minimal muscular weakness persisted.At birth a chest x-ray had been taken because of rapid breathing and jaundice and showed the heart to be of normal size. Clinical studies included: EKG which showed biventricular hypertrophy, needle liver biopsy which showed toxic hepatitis, and cardiac catheterization which showed no obstruction to left ventricular outflow. Liver and muscle biopsies revealed no biochemical or histological evidence of type II glycogexiosis (Pompe's disease). At thoracotomy, 14 milligrams of left ventricular muscle were removed. Total phosphorylase activity in the biopsy specimen was normal by biochemical analysis as was the degree of phosphorylase activation. By light microscopy, vacuoles and fine granules were seen in practically all myocardial fibers. The fibers were not hypertrophic. The endocardium was not thickened excluding endocardial fibroelastosis. Based on these findings, the diagnosis of idiopathic non-obstructive cardiomyopathy was made.
Specimen Surface Contamination and the Loss of Structural Detail in Freeze-Fracture and Freeze-Etch Preparations
Authors: Kreutziger G. Oscar 
Published: June 2020

The presence of particles and the absence of depressions or pits of sizes and numbers corresponding to the particles has raised definite questions on the interpretation of freeze-fracture and freeze-etch preparations. In shadow preparations it is well known that the thickness of the deposited metal can result in the loss of surface detail; holes and pits are filled-in and closed, fine particles are obscured, and the size of large particles increases. A similar sequential loss in specimen surface detail resulting from surface contamination prior to replication is illustrated in freeze-etch preparations of the tight junction of mouse heart muscle. Illustrations have been selected from the developmental period of the simple freeze-etch device and it's further modification.In the most favorable preparation the intracellular plasmalemma surface has a sparce particle population, it reflects the closer membrane apposition of the tight junction and the surface within the junction proper is particle free but is populated by numerous pits: the intercellular plasmalemma surface is covered with a dense particle population outside the junction and has the packed hexagonal particle array within the junction proper (Fig. 1).
Examination of Rabbit Fc Crystals
Authors: Robinson J. P. , Lenhert P. G. 
Published: June 2020

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.
Release of Neurosecretion in the Crayfish Sinus Gland
Authors: Shivers Richard R. 
Published: June 2020

The sinus gland is a neurohemal organ located in the crayfish eyestalk and represents a storage site for neurohormones prior to their release into the circulation. The sinus gland contains 3 classes of dense, membrane-limited granules: 1) granules measuring less than 1000 Å in diameter, 2) granules measuring 1100-1400 Å in diameter, and 3) granules measuring 1500-2000 Å in diameter. Class 3 granules are the most electron-dense of the granules found in the sinus gland, while class 2 granules are the most abundant. Generally, all granules appear to undergo similar changes during release.Release of neurosecretory granules may be initiated by a preliminary fragmentation of the “parent granule” into smaller, less dense vesicles which measure about 350 Å in diameter (V, Figs. 1-3). A decrease in density of the granules prior to their fragmentation has been observed and may reflect a change in the chemical nature of the granule contents.
Non-Functioning Delta Cell Carcinoma of Pancreatic Islets
Authors: Bencosme Sergio A. , Ramchand S. , Huang S. N. 
Published: June 2020

In recent years there has been considerable interest in the identity, structure and function of delta cells of pancreatic islets. Williams states that the Zollinger-Ellison Syndrome is associated with neoplasms of delta cells and that these cells secrete gastrin. However, other functions have also been attributed to these cells. An excellent critical review on the identity, structure and possible function of delta cells has been published by Fujita. Clearly all new criteria for identification of delta cells must refer back to those given by Bloom in his original description in 1931.The present report deals with a malignant islet cell tumor of the pancreas in a case autopsied twelve hours after death. By light microscopy tumor cells possessed the classical tinctorial properties of delta cells; the tumor was thus classified as a delta cell carcinoma. Considerable confusion exists on the ultrastructural identification of delta cells in man. Hence, it was decided to investigate the fine structure of these tumor cells and to compare them to non-tumor islet cells of the same patient. To best interpret our results in post mortem material the pancreas of three patients autopsied at three, six and twelve hours after death were processed and studied in a similar manner as the pancreas bearing the tumor. By electron microscopy three types of islet cells could be identified in pancreas taken three hours post mortem.
Electron Microscopy in Studies on the Relationship of Viruses to Tumors in Animals and Man
Authors: Dmochowski Leon 
Published: June 2020

Both DNA- and RNA-carrying viruses play a part in the origin of many tumors in animals and may be involved in some types of neoplasia in man. Presently only some RNA viruses and neoplasia will be discussed. Electron microscopy, combined with biophysical, biochemical and biological approach, has laid foundation of present-day knowledge of viruses being causative factors of many types of neoplasia in animals. The appearance, size, internal structure, and mode of development of a number of RNA-viruses in neoplasia are now known. Electron microscopy has either followed or preceded biological studies on causation of neoplasia by viruses. In either case its contribution has been invaluable.Since the observation of virus particles in mammary tumors of mice (Dmochowski, L. : J.Nat.Cancer Inst.15,785 (1954)), they are now known to be the causative agent of this neoplasia. They are widely distributed in milk of various strains of mice and present long before signs of neoplasia appear. Chemical, physical factors and leukemia virus may stimulate mammary tumor virus and lead to mammary neoplasia. Search for similar virus in milk and breast cancer of women revealed structures resembling virus particles.
The Fine Structure of Replicating Simian Adenoviruses in LLC-MK2
Authors: Pardo Matias , Slifkin Malcolm , Merkow Leonard , Sanchez Marie 
Published: June 2020

The simian adenoviruses SV20, SV30 and SA7 have been found to be oncogenic in the Syrian hamster. The growth characteristics and replicative cycle of these viruses in tissue culture therefore appeared appropriate to investigate. Cesium chloride purified simian adenovirus with an infectivity titer of 100 TCID50, was inoculated into monolayers of LLC-MK2 cells. Cells were fixed in osmium tetroxide and embedded for ultrastructural studies at 1, 3, 6, 9, 18, 24, 48, 72, 120 and 192 hours post-infection.At the first hour post-infection, virus particles were adsorbed to the plasmalemma and found within the peripheral cytoplasm of many LLC-MK2 cells (Fig. 1). Although the first detection of infectious virus occurred at 14 hours and infectivity titers did not reach a maximum until 30 hours, intranuclear virus particles were observed by 3 hours in typical adenovirus crystalline array (Fig. 2) by means of electron microscopy. These typical honeycomb arrayed virus particles at 3 hours provided evidence of significant replication in approximately 5 percent of tissue culture cells examined. Simultaneously, a classical nuclear inclusion manifested by peripheral condensation of nuclear chromatin was evident by light microscopy. As early at 6 to 9 hours, unusual intranuclear concentric membranes formed “tubes” which contained linear arranged virus particles (Fig. 3). In transverse or tangential sections, these “tubes” appeared cochlear-like in shape. In longitudinal section, these intranuclear tubular structures contained individual virus particles at various stages of maturation in a linear arranged order. This arrangement resembled “peas in a pod”.
Electron Microscopy of a Herpesvirus Isolated from Marek's Disease in Duck and Chicken Embryo Fibroblast Cultures
Authors: Nazerian Keyvan 
Published: June 2020

A herpes-like virus has been isolated from duck embryo fibroblast (DEF) cultures inoculated with blood from Marek's disease (MD) infected birds. Cultures which contained this virus produced MD in susceptible chickens while virus negative cultures and control cultures failed to do so. This and other circumstantial evidence including similarities in properties of the virus and the MD agent implicate this virus in the etiology of MD.Histochemical studies demonstrated the presence of DNA-staining intranuclear inclusion bodies in polykarocytes in infected cultures. Distinct nucleo-plasmic aggregates were also seen in sections of similar multinucleated cells examined with the electron microscope. These aggregates are probably the same as the inclusion bodies seen with the light microscope. Naked viral particles were observed in the nucleus of infected cells within or on the edges of the nucleoplasmic aggregates. These particles measured 95-100mμ, in diameter and rarely escaped into the cytoplasm or nuclear vesicles by budding through the nuclear membrane (Fig. 1). The enveloped particles (Fig. 2) formed in this manner measured 150-170mμ in diameter and always had a densely stained nucleoid. The virus in supernatant fluids consisted of naked capsids with 162 hollow, cylindrical capsomeres (Fig. 3). Enveloped particles were not seen in such preparations.
An Electron Microscopic Study of the Acute Effects of Hypothalamic Releasing Factors on the Anterior Pituitary Gland
Authors: Coates P.W. , Ashby E.A. , Krulich L. , Dhariwal A. , McCann S. 
Published: June 2020

The morphologic effects on somatotrophs of crude sheep hypothalamic extract prepared from stalk-median eminence were studied by electron microscopy in conjunction with concurrently run bioassays performed on the same tissue samples taken from young adult male Sherman rats.Groups were divided into uninjected controls and injected experimentals sacrificed at 5', 15', and 30' after injection. Half of each anterior pituitary was prepared for electron microscopic investigation, the other half for bioassay. Fixation using collidine buffered osmium tetroxide was followed by dehydration and embedment in Maraglas. Uranyl acetate and lead citrate were used as stains. Thin sections were examined in a Philips EM 200.Somatotrophs from uninjected controls appeared as described in the literature (Fig. 1). In addition to other components, these cells contained moderate numbers of spherical, electron-dense, membrane-bound granules approximately 350 millicrons in diameter.
Defects in Crystals
Authors: Lawless Kenneth R. 
Published: June 2020

One of the most important applications of the electron microscope in recent years has been to the observation of defects in crystals. Replica techniques have been widely utilized for many years for the observation of surface defects, but more recently the most striking use of the electron microscope has been for the direct observation of internal defects in crystals, utilizing the transmission of electrons through thin samples.Defects in crystals may be classified basically as point defects, line defects, and planar defects, all of which play an important role in determining the physical or chemical properties of a material. Point defects are of two types, either vacancies where individual atoms are missing from lattice sites, or interstitials where an atom is situated in between normal lattice sites. The so-called point defects most commonly observed are actually aggregates of either vacancies or interstitials. Details of crystal defects of this type are considered in the special session on “Irradiation Effects in Materials” and will not be considered in detail in this session.
A Review of Methods for Determining the Nature of Small Defect Clusters
Authors: Rudee M. L. 
Published: June 2020

When a crystalline material is damaged by fast neutron irradiation, the most common defects encountered are small aggregates of vacancies or interstitial atoms. The images observed range from about 150Å down to the resolution limits of the contrast producing mechanism. An understanding of these defects is quite important to theories of irradiation damage, and a significant effort has been directed towards unraveling their nature. The development of the appropriate diffraction contrast techniques has been marked by a number of controversies. Since many are now resolved, this seems a salutary time to put forward a review of the present state of affairs.An image of a defect cluster is a result of the strain field, either expansion or contraction, in the surrounding lattice. Calculations of the contrast from such a strain field have been performed by Ashby and Brown, and more recently by Rühle et al., and McIntyre and Brown. These authors used the two-beam wave-optical dynamical theory of diffraction contrast including anomalous absorption, and the images predicted have two-lobes, one darker and the other lighter than the background.
Hitachi Model XMA-5 Electron Probe Microanalyzer
Authors: Tomura  , Okano  , Hara  
Published: June 2020

The recent advancement in scientific instrumentation has been phenomenal. This is particularity true in the electron probe microanalyzer field. This paper describes the improvements made in the Hitachi Model XMA-5 Electron Probe Microanalyzer to achieve high performance.1.X-ray spectroscopy1-1.It is now possible to analyze a wide variety of elements including ultra light elements in minute concentrations with the advent of an increasing number of dispersing elements and high detectability.1-2.A linear crystal drive and direct wavelength read-out (with respect to the crystal) is employed in the spectrometer to assure simultaneous analyses of up to three elements by using three of the six crystals provided. For correction of absorbed X-rays and fluorescence excitation and with due consideration of the angular distribution of the characteristic X-rays, an X-ray take off angle of 38° (electron probe is incident vertically on the specimen surface) was adopted.
A New High Intensity Grid Cap for RCA-EMU-3 Electron Microscopes
Authors: Christov George , Lloyd Bolivar J. 
Published: June 2020

A new high intensity grid cap has been designed for the RCA-EMU-3 electron microscope. Various parameters of the new grid cap were investigated to determine its characteristics. The increase in illumination produced provides ease of focusing on the fluorescent screen at magnifications from 1500 to 50,000 times using an accelerating voltage of 50 KV.The EMU-3 type electron gun assembly consists of a V-shaped tungsten filament for a cathode with a thin metal threaded cathode shield and an anode with a central aperture to permit the beam to course the length of the column. The cathode shield is negatively biased at a potential of several hundred volts with respect to the filament. The electron beam is formed by electrons emitted from the tip of the filament which pass through an aperture of 0.1 inch diameter in the cap and then it is accelerated by the negative high voltage through a 0.625 inch diameter aperture in the anode which is at ground potential.