bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron Microscope Provided with a Six-Stage Image Forming Lens System
Authors: Arai Y. , Ishida Y. , Watabe T. , Harada Y. 
Published: June 2020

The image forming lens system of an electron microscope used for medical and biological applications has to meet the following requirements: (1) minimum off-axis aberration and distortion, (2) eliminated image rotation and focus deviation over wide magnification range, and (3) a wide field of view at low magnification. We have developed a new type of electron microscope which has a six-stage image forming lens system to satisfy the above requirements.The present paper describes the features of the electron microscope and also gives some application data for biological fields obtained with this instrument. The electron optical system is designed to provide a wide magnification range of 50x to l,000,000x by using a high resolution side entry goniometer with tilting facility of ±25°. Fig.l shows typical ray diagrams formed by the six-stage image forming system. The system consists of a dual objective (objective lens; OL and objective mini-lens; OM), triple intermediate lens (IL1, IL2 and IL3) and single projector lens (PL).
Epizootic Hemorrhagic Disease Virus Infection in Salivary Glands ofCulicoides Variipennis
Authors: Foster Neil M. , Jones Robert H. 
Published: June 2020

Epizootic hemorrhagic disease virus (EHDV) is transmitted to ruminants by the biting gnatculicoides variipennis. In cultured cells, EHDV replicated in cytoplasmic matrixes; filaments and macrotubules were observed in the cytoplasm and in association with viroplasms. This report describes EHDV infection ofC. variipennissalivary gland cells.Normal colony female flies were infected either by intrathoracic inoculation of EHDV propagated in BHK-21 cell cultures (CC) or orally on EHDV-infected CC fluids mixed 1:9 with normal sheep blood. EHDV-exposed flies and noninfected controls were maintained alternately on water and a 10% sugar solution until salivary glands were removed at 9 (inoculated flies) and 19 (orally exposed flies) days for processing and viewing in thin section.Viroplasms were observed in the cytoplasm often in intimate association with progeny virions and macrotubules (Fig. 1). Macrotubules and progeny virions also were found free in the cytoplasm away from viroplasms (Fig. 2). Macrotubules were found in bundles in ordered array whether in association with viroplasms or free in the cytoplasm.
Studies on the Fungal Pathogen of Dutch Elm Disease
Authors: Mazzone H.M. , Wray G. , Zerillo R. 
Published: June 2020

The fungal pathogen of the Dutch elm disease (DED), Ceratocystis ulmi (Buisman) C. Moreau, has eluded effective control since its introduction in the United States more than sixty years ago. Our studies on DED include establishing biological control agents against C. ulmi. In this report we describe the inhibitory action of the antibiotic polymyxin B on the causal agent of DED.In screening a number of antibiotics against C. ulmi, we observed that filter paper discs containing 300 units (U) of polymyxin B (Difco Laboratories) per disc, produced zones of inhibition to the fungus grown on potato dextrose agar or Sabouraud agar plates (100mm x 15mm), Fig. 1a. Total inhibition of fungal growth on a plate occurred when agar overlays containing fungus and antibiotic (polymyxin B sulfate, ICN Pharmaceuticals, Inc.) were poured on the underlying agar growth medium. The agar overlays consisted of the following: 4.5 ml of 0.7% agar, 0.5 ml of fungus (control plate); 4.0 ml of 0.7% agar, 0.5 ml of fungus, 0.5 ml of polymyxin B sulfate (77,700 U). Fig. 1, b and c, compares a control plate and polymyxin plate after seven days.
Ultrastructural Changes in Tumor Cells During Human Peripheral Blood Monocyte-Mediated Cytotoxicity
Authors: Muse K. E. , Fischer D. G. , Koren H. S. 
Published: June 2020

Mononuclear phagocytes, a pluripotential cell line, manifest an array of basic extracellular functions. Among these physiological regulatory functions is the expression of spontaneous cytolytic potential against tumor cell targets.The limited observations on human cells, almost exclusively blood monocytes, initially reported limited or a lack of tumoricidal activity in the absence of antibody. More recently, freshly obtained monocytes have been reported to spontaneously impair the biability of tumor target cells in vitro (Harowitz et al., 1979; Montavani et al., 1979; Hammerstrom, 1979). Although the mechanism by which effector cells express cytotoxicity is poorly understood, discrete steps can be distinguished in the process of cell mediated cytotoxicity: recognition and binding of effector to target cells,a lethal-hit stage, and subsequent lysis of the target cell. Other important parameters in monocyte-mediated cytotoxicity include, activated state of the monocyte, effector cell concentrations, and target cell suseptibility. However, limited information is available with regard to the ultrastructural changes accompanying monocyte-mediated cytotoxicity.
Fine Structure of Type IV Glycogenosis
Authors: Simons P.K. 
Published: June 2020

Glycogenosis is defined as any condition in which the tissue concentration of glycogen is increased. There are currently ten recognized variants of glycogenosis that are heritable inborn errors of metabolism. The specific enzymatic defect in each of the variants is known or at least suspected. In all cases, the enzymatic defect prevents the proper metabolism or formation of the glycogen molecule. The clinical and histologic differences between the types of glycogenosis is important to a proper diagnosis after the presence of such a condition is realized. This study was initiated to examine the ultrastructure of the rare Type IV Glycogenosis (Amylopectinosis) of which there is very little morphologic characterization in the literature.Liver tissue was obtained by needle biopsy from a 12-month-old Oriental female who was originally admitted to the hospital after observation of poor development, loss of appetite, and hepatomegaly. The majority of the tissue was fixed for light microscopy in neutral buffered formalin and processed using routine and special staining procedures (reticulin, trichrome, iron, copper, PAS, PAS-diastase and PAS-pectinase.
SEM Evaluation of Fluoride Pretreatment Effects on Acid-Etching of Caries-Like Enamel Lesions In Vitro
Authors: John Hicks M. 
Published: June 2020

Acid-etching of enamel surfaces has been performed routinely to bond adhesive resin materials to sound dental enamel as a caries-preventive measure. The effect of fluoride pretreatment on acid-etching of enamel has been reported to produce inconsistent and unsatisfactory etching patterns. The failure to obtain an adequate etch has been postulated to be due to fluoride precipitation products deposited on the enamel surface. The purpose of this study was to evaluate the effects of fluoride pretreatment on acid-etching of carieslike lesions of human dental enamel.Caries-like lesions of enamel were created in vitro on human molar and premolar teeth. The teeth were divided into two fluoride treatment groups. The specimens were exposed for 4 minutes to either a 2% Sodium Fluoride (NaF) solution or a 10% Stannous Fluoride (SnF2) solution. The specimens were then washed in deionized-distilled water. Each tooth was sectioned into four test regions. This was carried out to compare the effects of various time exposures (0 to 2 minutes) and differing concentrations (10 to 60% w/w) of phosphoric acid (H3PO4) on etching of caries-like lesions. Standard preparation techniques for SEM were performed on the specimens.
Localization of Alpha Bungarotoxin Binding Sites in the Rat Carotid Body Using Horseradish Peroxidase-Conjugated Toxin
Authors: Chen I-Li , Mascorro Joe A. , Lumsden Patricia W. , Yates Robert D. 
Published: June 2020

In a previous communication, we reported binding of 125I-alpha bungarotoxin (αBgt) to certain parenchymal cells in the rat carotid body. However, the exact cell types exhibiting the binding sites were not definitively identified. During the present study, horseradish peroxidase (HRP)-conjugated αBgt was used in order to obtain a precise location of αBgt-acetylcholine (ACh) receptor sites in the carotid body. αBgt was conjugated to HRP by a two-step technique, and its specificity to ACh receptors was tested histochemically by utilizing frozen sections of the mouse diaphragm. Carotid bodies from adult rats, with or without preincubation in 10-3M d-tubocurarine (d-Tc), were incubated in approximately 700 nM αBgt-HRP for one hour at 37°C. The tissue was washed, fixed in glutaraldehyde, reacted with a diaminobenzidine-hydrogen peroxide mixture, postosmicated and embedded in Epon 812.Semithin sections revealed that the conjugate penetrated throughout the carotid body and became localized in all groups of parenchymal cells. Preincubation in 10-3M d-Tc completely abolished the labelings.
Dedifferentiation of the Axolemma Associated with Demyelination
Authors: Rosenbluth J. , Sumner A. , Saida T. 
Published: June 2020

Freeze-fracture analysis of myelinated nerve fibers has shown that the axolemma has a highly differentiated structure. The node is characterized by a high concentration of intramembranous particles, primarily in the E fracture face, which may represent the sodium channels known to be concentrated there, and the paranodal axolemma is characterized by a distinctive paracrystalline pattern that corresponds to the intercellular junction formed with the terminal “loops” of myelin lamellae. Studies of myelin formation in normal animals and of myelin-deficient mutant animals indicate that the development of these axolemmal specializations is profoundly influenced by the associated myelinforming cells. The present study considers whether or not nodal or paranodal specializations that have already formed persist after demyelination.In order to investigate this question, specimens of peripheral nerves were examined following exposure to an antiserum to galactocerebroside (GC), which is known to cause a predictable series of changes leading to demyelination. Freeze-fracture replicas of rat spinal roots exposed to anti-GC serum in situ for six hours showed marked changes in the paranodal axolemma.
Studies on the Galactose-Specific Recognition System of Mammalian Liver
Authors: Hubbard A. L. , Wall D. A. , Zeitlin P. L. , Hong S. W. 
Published: June 2020

The rapid removal of circulating desialylated glycoproteins from the blood plasma of mammals is well-documented, occurs exclusively in the liver and is mediated by a carbohydrate recognition system present only in hepatocytes. After binding to a plasma membrane receptor that recognizes galactose, glucose or N-acetylgalactosamine residues on their oligosaccharide chains, ligands are rapidly internalized, transported within membrane-bound structures to lysosomes and subsequently degraded. The fate of the receptor is less clear, although it is reutilized. Our recent experiments have addressed three questions: 1) What is the detailed intracellular pathway taken by asialo-glycoproteins (ASGP's)? 2) Where on the hepatocyte cell surface are ASGP's bound? and 3) What is the intracellular distribution of the ASGP receptor?Two electron microscopic tracers have been used to investigate the internalization of ASGP's by hepatocytes: asialoorosomucoid covalently coupled to horseradish peroxidase (ASOR-HRP); and lactosaminated ferritin (Lac-Fer), a ferritin molecule to which 90-110 lactose molecules have been attached via their glucose moieties.
Structural Changes in Cerebellar Cortex Induced by Intrauterine Growth Retardation in the Rat
Authors: Feria-Velasco Alfredo , Tapia-Arizmendi Guadalupe 
Published: June 2020

Intrauterine growth retardation (IUGR), both in human and experimental animals, can be produced by two types of factors : intrinsic and extrinsic. Intrinsic growth failure may result from congenital and/or genetic alterations. Two main categories of extrinsic growth failure have been described: a) produced by interfering with placental blood flow to fetuses; and b) produced by maternal dietary restriction. In both types, alterations of neurological functions are observed, mainly related to learning and memory.In various models of IUGR, the cerebellum is more affected than the other structures of the central nervous system,according to biochemical studies carried out by different authors.For the present work, IUGR was produced in Sprague Dawley rats according to Wigglesworth's method by ligation of one uterine artery at the 15th gestational day. The products and placentas were obtained by cæsarean section at the 21st gestational day to be weighed and studied with the light and electron microscope. The data here presented correspond to the ultrastructural study of cerebellar cortex of neonates perfused intravascularly with 2.5% buffered-glutaraldehyde, postfixed with buffered osmium tetroxide and processed for transmission electron microscopy.
Ultrastructure of Human Placenta: Effects of Maternal Drinking
Authors: Amankwah K.S. , Weberg A.D. , Kaufmann R.C. 
Published: June 2020

The effects of maternal alcohol consumption upon the fetus during gestation have been well documented in the literature. The data in such studies are primarily based on gross morphological evaluations of the fetus and the placenta. The placenta is an organ specially formed during gestation to exchange metabolites between mother and fetus. Although it functions by selectively transporting certain materials from the maternal blood, it is freely permeable to other substances such as alcohol. In this investigation, we have studied the effects of maternal alcohol consumption on the ultrastructure of the human placenta by TEM and SEM.Placentae from four women who admitted to consuming copious amounts of alcoholic beverages and four controls were used in this study. Villous tissue from centrally located cotyledons of freshly delivered placentae were fixed in 3% gluteraldehyde in 0.1M cacodylate buffer pH 7.3.Samples for SEM were processed by OTOTO3 technic, dehydrated and critical point dried with CO2. Samples for TEM were post-fixed in Osmium ferro- cyanide (1:1 mixture of 1.5% aqueous OsO4 and 2.5% K4Fe(CN)6).
Morphologic Changes in the Egg of the Polychaete Worm Mercierella Enigmatica after Fertilization
Authors: Humphreys Walter J. 
Published: June 2020

Comparative ultrastructural studies of changes in the morphologies of invertebrate eggs that occur after fertilization may shed light on the evolution of the fertilization process and the incorporation of mechanisms that may serve to insure monospermy as well as to provide protective envelopes for the developing embryo. This report describes changes that occur in the egg of Mercierella enigmatica as noted 35 minutes after fertilization.Eggs or sperm were shed spontaneously when the worms were pulled from their tubes and placed in individual watch glasses containing sea water. The unfertilized eggs were fixed for 1 hour in 2.5% glutaraldehyde in 0.1M cacody- late buffer at pH 7.5. The eggs were rinsed in sea water and post fixed for 1 hour in 1% osmium tetroxide buffered with 0.1M phosphate buffer at pH 7.5. Other eggs were fertilized by the addition of sea water containing sperm and fixed as above after 35 minutes. Eggs were embedded in Epon and compared by TEM. Embedments of the unfertilized eggs and fertilized eggs were fractured and coated with vacuum evaporated gold for SEM.
Activated Pectin Stained with Heavy Metals
Authors: Smith Craig A. , Hanker Jacob S. , Malcolm Brown R. 
Published: June 2020

Pectin was visualized in carrot tissue culture with a stain utilizing hydroxylamine and iron. Actively growing cells were fixed in glutaraldehyde or paraformaldehyde. The pectin was activated by an alkaline hydroxylamine treatment. When the so formed pectic hydroxamic acids were reacted with ferric chloride, a reddish-brown color was visible en masse, but the cells were not sufficiently stained for either light or electron microscopy.We hoped to intensify the stain by bridging iron to osmium. Since one Fe (III) complexes three gallocyanins, we tested this dye as a bridge in an attempt to amplify the staining. Thiocarbohydrazide (TCH) was tested as an alternate bridge. After excess iron was washed out, the cells were treated with either 1% gallocyanin for one hour, or 0.5% TCH for one minute. After excess bridge was removed by a second wash, a portion of each treatment was placed in 1% osmium tetroxide for one hour.
The Extent of Platinum-Carbon Electron Beam Gun Degassing Before Replication Can Change the Size and Frequency of Replicated Small Particles
Authors: Ruben George C. 
Published: June 2020

The freeze-fracture of cellular membranes generally reveals particles of different sizes distributed on a membrane fracture face. These views of the membrane are generally characterized by the frequency of particles per area and a particle shadow width distribution with its mean. It is generally assumed that these particle size and frequency parameters can be influenced by the replica film thickness and the shadowing angle. It is not known whether the extent of Pt-C electron beam gun degassing prior to the replication step can change the shadow width distribution means of spherical gold particles, and their percent representation following replication.Two experiments were performed in a Balzer's model 360M freezing microtome (10-6 torr) in which the EKV 552 Pt-C electron beam gun was degassed for 19 sec. (film I) and for 120 sec. (film II) at a current setting of 5 on the EVM 052 control unit. The gold ball calibration grids (2) were cooled to -96°C and covered with the knife arm (-196°C) during degassing.
Correlation of Ultrastructural, Morphometric and Biochemical Changes in Rats after Treatment with the Hypolipidemic Drugs Clofibrate and Probucol
Authors: Visscher G. E. , Robison R. L. , Engstrom R. G. 
Published: June 2020

It was our goal to evaluate the reliability and reproducibility of semi-automated morphometric techniques in the analysis of structural changes observed during drug safety assessment. Studies are presented to correlate the ultrastructural, morphometric and biochemical effects that the two hypolipidemic agents, clofibrate and probucol, produce in rats.Charles River CD Sprague-Dawley derived male rats (200-225 g body wt.) were used for the three studies performed. In studies I and II, clofibrate was administered as a dietary admixture to approximate a dosage of 300 mg/kg/day for six days. In study III, clofibrate and probucol were given as dietary admixtures to approximate dosages of 300 and 250 mg/kg/day respectively for fourteen days. Processing of hepatic specimens for electron microscopy included fixation in 1.3% sym-collidine buffered osmium tetroxide, ethanol dehydration and Epon embedment. Thin sections (600Å) were stained with uranyl acetate and lead citrate. Survey and photography was performed in the manner according to Weibel. Final prints (14,400x) were analyzed with a Zeiss MOP for morphometric quantitation.
Characteristic Lesions in Mouse Retina Irradiated with Accelerated Iron Particles
Authors: Malachowski M.J. , Philpott D.E. , Corbett R.L. , Tobias C.A. 
Published: June 2020

During the Apollo flights to the moon the astronauts reported light flash sensations after dark adaption. The cause of these “flashes” is due to the passage of heavy energetic cosmic-ray particles (HZE) through the retina. The rate of energy transfer of the HZE particle in tissue along the path of the particle is proportional to the square of the atomic number and approximately inversely proportional to the kinetic energy. Thus, a single iron particle (Z=26) transfers 676 times more energy than a proton of the same velocity. A critical question concerning the potential hazards of HZE particles is whether or not an individual particle can inflict serious damage to a series of ceils.A program is underway to determine the radiation hazards of HZE particles using the Bevalac, a heavy-ion accelerator at LBL. Our earlier work with helium, carbon, neon, and argon particles, and exposure of rats to HZE particles in space flight demonstrated some deleterious biological effects.
Purkinje Cell Morphology Under Experimental and Natural Rabies Infection in Different Species
Authors: Hernández-Jáuregui P. , González-Angulo A. , Hernández-Baumgarten E. 
Published: June 2020

Purkinje neurons frequently showed rabies inclusion bodies in natural rabies infection thus providing elements for an accurate diagnosis of rabies. After studying several sections of cerebellar cortex of experimentally infected mice with fixed rabies virus, no viral inclusion bodies were found. Degenerative changes in Purkinje cells however were commonly found as mayor evidence of cell damage or infection. (Fig. 1,2) The fact that no viral inclusions (Negri bodies) were present in Purkinje neurons of experimentally infected animals and instead there were definite degenerative changes prompted us to study the ultrastructure of these cells in an attempt to find an explanation of this peculiar reactions.Experimentally infected animals; 20 mice were infected in the brain using the Mazatan and V319 fixed rabies strains isolated from infected Desmodus rotundus vats. Five dogs were innoculated in the maseteric muscles using a salivary gland suspension previously obtained from natural rabid dogs. The cerebellar cortex of these animals were fixed by vascular perfusion and conventionally studied for transmission electron microscopy.
Use of the Yolk (Vitelline) Membrane as an In Vitro Model to Study Yeast Adherence
Authors: Persi M. A. 
Published: June 2020

Quantitation of viral, bacterial and fungal pathogenicity has been assessed using the chorioallantoic membrane (CAM) of fertilized chicken eggs, Gall us domestica. Although virulence of pathogens such as Candida albicans can be measured by inoculating the CAM, there are still limitations in controlling various endogenous environmental parameters inside the egg. The in vitro membrane model introduced here, when used to study adherence and how it may lead to pathogenicity, has several advantages. It is simple and inexpensive membrane and membrane holder apparatus which allows for easy membrane removal and isolation; but the best advantage is the ability to control the environmental parameters at the membrane's surface such as CO2/O2 tension, pH and temperature which may play an important role in attachment and which cannot be controlled while the CAM is inside the egg.The egg shell of a large unfertilized grade A egg was aseptically punctured, the inner and outer shell membranes were removed at the air-sac end of the egg, the egg white was extracted and the unruptured yolk was removed from the egg shell.
Microanalysis of Calcium and Phosphorus in Biology Using Electron Energy Loss Spectroscopy
Authors: Leapman R.D. , Swyt C.R. 
Published: June 2020

Quantitative microanalysis of the important elements calcium and phosphorus in thin biological samples is normally performed using EDX spectroscopy. Sometimes, however, it is helpful to obtain additional information such as the relative amounts of nitrogen and oxygen present. EELS is sensitive to these low-Z elements and in certain cases can also improve P and Ca detection limits because of the higher EELS counting rate. Here we demonstrate the feasibility of Ca:P:Q:N ratio determinations, though we must be cautious about the N and O ratios because of mass loss.Fig. 1(a) is a STEM image of isolated dense bodies extracted from human blood platelets by sonication and then centrifuged onto a thin carbon substrate. The dense bodies which are typically 1000 Å in diameter were well separated from other constituents of the cells. Fig. 2(a) shows an EELS spectrum from a dense body about 800 Å in diameter. It was recorded at 100 keV beam energy with a Hitachi spectrometer attached to an H700H electron microscope.