bluuebunny/crossref_metadata_2025_split huggingface dataset:
High magnification in-lens field emission SE-I SEM of carbon based styrenes, diamonds, and endothelial cell membranes
Authors: Apkarian Robert P. , Tarr Jonathan A. , Kaufmann Myron J. , Menger Fredric M. 
Published: June 2020

High resolution topographic imaging of carbon based samples have been problematic primarily due to the low secondary electron-I yield from specimens of low atomic mass. Both cold cathode and Schottky field emission (SFE) in-lens SEMs produce small beam diameters (5-10 Å) and achieve their highest resolution when operated at high (20-30 keV) accelerating voltages. The Topcon in-lens SFE-SEM/STEM has been in service at Emory U. for four years, and has generated quality images of carbon based materials and biological membranes. Enrichment of the SE-I signal from hydrocarbon based specimens was achieved by the application of a 1 run thick, fine grain Cr film and provided images of 1-2 nm particulate features without decoration or enlargement. Specimen beam interaction and the resultant particle contrast in a high magnification analog image recording was compared for graphitic carbon, diamond, and chromium coated polyvinylstyrene and fenestrated endothelial cell membranes (FECM).Chemical vapor deposition (CVD) was used to deposit various forms of carbon on Si (111) wafers.
Human T-lymphocytes (Jurkat cells) expressing TAT-72: LM and TEM
Authors: Gilloteaux J. , Koch J. , Jamison J. M. , Summerst J.L. 
Published: June 2020

The human immunodeficiency virus (HIV-1) is dependent upon the synthesis of TAT for efficient transcriptional activation and replication1. TAT serves to transactivate the HIV-LTR which leads to an increased transcriptional activation of approximately 1000 fold.We have transfected human T-lymphocytes with an expression vector containing the HIV-1 LTR driving the synthesis of TAT-72. A stable cell line was generated by selection with G418.Cells were centrifuged with a cytospin and stained for nucleic acids with methyl green and pyronin Y in order to visualize and to localize DNA and RNA respectively in each preparation examined by light microscopy (LM). In addition, cells were fixed with a 3.5% glutaraldehyde buffered solution (0.1M Na cacodylate) for 5 min at room temperature, 35 min at 4°C, centrifuged in a microfuge (400 rpm, 3 min) to obtain a cellular pellet. Cell pellets were washed in a buffer-sucrose solution and postfixed in a 1.5% aqueous solution of OsO4. Dehydration and epoxy embedding was followed by sectioning for TEM, following treatment with uranyl and lead salts.
SEM of the tongue and related vomeronasal structures in Coluber constrictor and Uta stansburiana
Authors: Froerer J. , Gardner J. S. 
Published: June 2020

The forked tongue in snakes and lizards serves to follow the pheromone trails of both prey and conspecifics. The three phases of the tongue flicking cycle are interrelated with three functional structures involved with the transportation of stimulus particles from the environment to the vomeronasal organ (VNO). (1) The sample phase involves protrusion of the tongue, collection, and transfer of stimulus particles to the anterior processes. (2) A transfer phase in conjunction with the anterior processes serves to facilitate the collection and localization of stimulus particles from the tongue. (3) The delivery phase includes anterior process elevation and the delivery of particles to the VNO. The VNO simultaneously deciphers the chemical concentrations, enabling the animal to follow pheromone trails in relation to the most volatile side, right or left. The morphology of the tongue, anterior processes, and VNO of a previously unevaluated snake and lizard are presented here.Snake species Coluber constrictor and lizard species Uta stansburiana were used in this study. Snakes were collected in Northern Utah and lizards were collected in Southern Utah. All specimens were prepared for scanning electron microscopy using standard techniques.
Molecular chaperones HSP-70 and BiP are present in the secretory pathway of exocrine glands
Authors: Menini T. , Bendayan M. 
Published: June 2020

In the past few years the study of a new group of proteins, the molecular chaperones, has demonstrated their relevant roles in cell biology. These proteins have been extremely well conserved during evolution, with percentages of homology reaching 50% between members of the same family (l).The heat shock 70 kDa family of proteins belonging to the molecular chaperone group includes at least 4 members which are permanent residents of several cellular compartments. Besides being induced by stress, these proteins fulfil many important functions such as collaborating with the proper folding and assembly of newly synthesized proteins and facilitating their transport and translocation into organelles (2).Different studies have demonstrated the involvement of these proteins in cell secretion in bacteria and yeast (3). Few data are however available for mammalian cells (4). In this regard, we have set out a study to demonstrate the presence and localization of two members of this family of proteins, the HSP-70 and the BiP, on several exocrine glands.
Recognition-alignment and adhesion in myoblast fusion
Authors: González Santander R. , Toledo Lobo M.V. , Martínez Alonso F.J. , Martínez Cuadrado G. , González-Santander Martínez M , Monteagudo M. 
Published: June 2020

Myoblast fusion results from a sequence of different stages, previously demonstrated “in vitro”. After withdrawal from the cell cycle, myoblasts align forming long chains, in a process termed “recognition-alignment”. This stage is extracellular Ca2+ and N-Cadherin dependent. Alignment is followed by adhesion, defined as the stage prior to membrane fusion when aggegates are resistant to dispersal by EDTA. Adhesion is extracellular Ca2+-independent and N-CAM-dependent. Membrane fusion originates multinucleate myotubes.We have studied these stages of myoblast fusion at the brachial myotome of chick embryo from 51 to 105 h. of incubation. Samples were obtained by embryo microdissection and included the neural tube, the notochord and the brachial somites. These samples were embedded in araldite by conventional methods. Some samples were embedded in Unicryl, a recently formulated GMA derived resin.The first myoblasts clusters were observed in the ventral-lateral region of the brachial myotome in 22-24 Hamburger and Hamilton stages embryos. Clusters of pre-fusion myoblasts are usually surrounded by “electrondense blast cells” within a basal lamina in process of formation.
Cytochemical study of glycogen in myoblasts of the chick embryo myotome
Authors: González Santander R. , Toledo Lobo M.V. , Martínez Alonso F.J. , Martinez Cuadrado G. , González-Santander Martínez M. , Monteagudo M. 
Published: June 2020

Potassium ferrocyanide-reduced osmium has been used as secondary fixative to study the presence of glycogen in different tissues. However, this method has not been previously applied to skeletal muscle development research. This study reports the use of this method to analyze the structure and cytoplasmic distribution of glycogen particles in the myoblasts of the brachial myotome of chicken embryos at 51-105 h. of incubation (Hamburger and Hamilton stages 16 to 25).In those sections post-fixed with potassium-ferrocyanide reduced osmium it is observed that glycogen particles stain in contrast to the rest of the structures of the cell (Figs. 1,2). In those sections processed for T.E.M., following conventional methods, glycogen particles are occasionally observed in less contrast and number that those with potassium-ferrocyanide reduced osmium. An explanation for this differences might be in the effects of potassium-ferrocyanide reduced osmium fixation preventing the loss of glycogen during dehydration and staining with uranyl acetate. We conclude that this cytochemical method may be specific for glycogen detection.
A method for encystation of Entamoeba invadens
Authors: Morales-Vallarta M. , Villarreal-Treviño L. , Ramíez-Bon E. , Said-Fernández S. , Mata-Cárdenas B. 
Published: June 2020

Some axenic encystaticn media for Entamoeba invadens have been described for different authors: Rengpien and Bailey medium (AEM (1), Vázquezdelara-Cisneros and Arroyo-Begovich (low glucose medium) (2) and Das et al. medium (3). The first medium must aging for one month for reach maturity, moreover its efficiency is also variable, on the other hand, the three media require cells at middle log-phase for good results. In this paper we report not a medium but a method for encystation of Entamoeba invadens.Trophozoites of Entamoeba invadens IP-1 strain were incubated with 103 cells/ml in 16 × 150 mm screw capped tubes, each containing 10 ml of culture medium (TP-S-1 (4) or TYI-S-33 (5) or FEHPS (6)) without vitamines (except FEHPS medium), and gassed with CO2 (0.2 l/min/2 min) through a pasteur pi _ pette with a cotton filter and incubated to 25°C. After 4 days the culture medium is eliminated and sustituted with 10 ml of the same medium but without glucose, newly gassed as above mentioned and incu bated to 25°C. After 4-5 days, formation of cystic structures reach a maximum efficiency of 70-80%.
Rabbit extrasinovial regenerating tendon: an experimental study
Authors: González Santander R. , Plasencia Arriba M.A. , Lopez Alonso A. , Toledo Lobo M.V. , Martínez Cuadrado G. , Martínez Alonso F.J. , González-Santander Martínez M. , Monteagudo M. 
Published: June 2020

The roles of the extrasynovial tendon cells (Achilles tendon) throughout the repairing process following injury are controversial. This study was performed to investigate the ultrastructural features of activated tenocytes and collagen synthesis experienced while healing after partial tenotomy and repair.Adult rabbit Achilles tendons were partially tenotomized. Before the suture of the paratenon, the borders of the surgical dissection were treated with different substances copolimerized with hydrogel. Hydrogel non-treated, tenotomized tendons were considered as controls. The rest of the samples were treated with hydrogel alone or hydrogel with E-vitamin. Rabbit legs were immobilized for 3, 10, 20 and 30 days. Samples from tenotomized and normal tendons were embedded in parafin and in Spurr and Araldite resins by conventional methods.With LM, a more pronounced healing process was observed in tendons treated with hydrogels if compared with controls, but this comparative study needs further investigation. During the process of repair, different stages can be identified: inflammation, revascularization and angiogenesis, cell proliferation, collagen synthesis and fibrillogenesis, and alignment/organization of collagen fibers into bundles oriented in the longitudinal axis of the tendon.
Microanatomical changes of the cerebral capillary network in aged rats: influence of treatment with a dihydropyridine-type calcium antagonist
Authors: Zaccheo D. , Amenta F. 
Published: June 2020

A variety of age-dependent changes affect cerebral vasculature. Morphological changes of the brain microvasculature characterized by microvascular fibrosis , vascular convolutions , thickening or membranous changes of the capillary basal membrane and gliofibrillary proliferation have been reported with aging. These changes may be related with age-dependent impairment in behavioral performance. Increasing evidence suggests that Ca+2 antagonists of the dihydropyridine family, which are used primarily in the therapy of cardiovascular disorders may be useful for treating neurologic diseases including cerebral ischemia, age-related neurodegenerative disorders, senile dementia and epilepsy. This in view of the capability of these compounds to decrease Ca+2 overload which can result in increased cell death.Recent studies have shown that the dihydropyridine Ca2+ antagonists delayed the expression of agerelated microvascular changes in the rat forebrain and sciatic nerve without reducing systolic blood pressure. The present study was designed to assess the influence of long term treatment with the dihydropyridine derivative darodipine [diethyl 4-2,1,3- (benzoxadiazal-4-yl)-l,4-dihydro-2,6-dimethylpyridine- 3,5-dicarboxylate, PY 108-068] on age-related microvascular changes occurring in the rat cerebral cortex and hippocampus. The brain capillary network was investigated using alkaline phosphatase histochemistry associated with image analysis.
Measurement of spontaneous neuronal membrane activity by time lapse confocal microscopy
Authors: Selinfreund R H. , Cornell-Bell A. H. 
Published: June 2020

Cellular electrophysiological properties are normally monitored by standard patch clamp techniques . The combination of membrane potential dyes with time-lapse laser confocal microscopy provides a more direct, least destructive rapid method for monitoring changes in neuronal electrical activity. Using membrane potential dyes we found that spontaneous action potential firing can be detected using time-lapse confocal microscopy. Initially, patch clamp recording techniques were used to verify spontaneous electrical activity in GH4\C1 pituitary cells. It was found that serum depleted cells had reduced spontaneous electrical activity. Brief exposure to the serum derived growth factor, IGF-1, reconstituted electrical activity. We have examined the possibility of developing a rapid fluorescent assay to measure neuronal activity using membrane potential dyes. This neuronal regeneration assay has been adapted to run on a confocal microscope. Quantitative fluorescence is then used to measure a compounds ability to regenerate neuronal firing.The membrane potential dye di-8-ANEPPS was selected for these experiments. Di-8- ANEPPS is internalized slowly, has a high signal to noise ratio (40:1), has a linear fluorescent response to change in voltage.
SEM study of the morphological effects of kinetin and zeatin on the growth and development of the apical meristem in wheat
Authors: Hutchins G. M. , Gardner J. S. 
Published: June 2020

Cytokinins are plant hormones that play a large and incompletely understood role in the life-cycle of plants. The goal of this study was to determine what roles cytokinins play in the morphological development of wheat. To achieve any real success in altering the development and growth of wheat, the cytokinins must be applied directly to the apical meristem, or spike of the plant. It is in this region that the plant cells are actively undergoing mitosis. Kinetin and Zeatin were the two cytokinins chosen for this experiment. Kinetin is an artificial hormone that was originally extracted from old or heated DNA. Kinetin is easily made from the reaction of adenine and furfuryl alcohol. Zeatin is a naturally occurring hormone found in corn, wheat, and many other plants.Chinese Spring Wheat (Triticum aestivum L.) was used for this experiment. Prior to planting, the seeds were germinated in a moist environment for 72 hours.
Ultrastructural changes in roots of peppers resistant and susceptible to Phytophthora capsici
Authors: Ilarslan H. , Ustun A.S. , Yilmazer R. 
Published: June 2020

The infection by Phytophthora capsici Leonian causes foliar blight and crown and root rot of pepper plants. The ultrastructural examination of resistant and susceptible host-pathogen interactions was conducted in the pepper cultivars Ince Sivri-35, PM217, and PM702=CM 334 following inoculation with Phytophthora capsici. Responses were characterized and compared with healthy non-inoculated controls at 2,4 and 6 days after inoculation. Numerous ultrastructural studies have been made of the interaction of various host plants Phytophthora spp. No ultrastructural studies comparing the resistant and susceptible reactions of pepper cultivars to P. capsici. have been reported. It is important to examine the ultrastructural changes in inoculated and infected tissue of resistant and susceptible pepper cultivars to P. capsici. Information reported here characterizes the processes of pathogen containment in resistant interactions and compares these with the processes occuring in susceptible interactions.After 2 days in susceptible interactions, the pathogen grew intercellularly in roots, whereas in resistant interactions only a few intercellular hyphae were observed penetrating the host cells and forming haustoria.
Immunolocalization of lactase in the crypt and villus enterocytes of the neonatal pig intestinal epithelium
Authors: Heath Julian P. , Kömüves László G. 
Published: June 2020

The crypt is the proliferative compartment of the intestinal epithelium where pluripotent stem cells continuously divide giving rise to committed daughter cells that follow a differentiation pathway as they migrate out of the crypt and along the villus axis. Certain cell antigens and markers are crypt-cell specific. Others, such as brush border enzymes, are thought to be expressed only on fully differentiated enterocytes, a theory supported by in situ hybridization analyses that reveal an absence of enzyme mRNAs in the crypt. But recent studies using immunocytochemical detection methods indicated that the brush border enzymes sucrase-isomaltase, aminopeptidase N and dipeptidylpeptidase IV are in fact expressed by both crypt and villus enterocytes. We are using immunogold electron microscopy to examine the effects of diet on enzyme expression in the newborn pig intestine.Tissues were collected from the jejunum of newborn and 9 day-old piglets. Cryosections (100 nm thick) were incubated in monoclonal anti-pig lactase antibody (PBB.3.7 from Dr. A. Quaroni, Cornell Univ) followed by 17 nm gold-conjugated anti-mouse immunoglobulin G.
Ultrastructural distribution of steroid sulfatase activity and mRNA in the human kidney
Authors: Nishikawa M. , Nakazawa T. , Kanda N. , Aikawa E. , Toma H. 
Published: June 2020

Steroid sulfatase (STS) is a microsomal enzyme catalyzing hydrolysis of 3β-hydroxysteroid sulfatases, including dehydroepiandrosterone sulfate, cholesterol and estrogen precursors. STS exists widely in various tissues and is involved in the metabolism of steroid hormones which play a critical role in cell proliferation and may be related to cancer induction in several organ systems. In the kidney, the proximal and distal portions of the nephrons have been suggested as possible sites of synthesis or as target tissues for steroid hormones. However, the presence and the role of STS in the human kidney have not been fully investigated. In this study, we examined the distribution of STS activity and mRNA in human renal tissue by enzyme histochemistry and in situ hybridization at the light and electron microscopic level.Renal tissue specimens were taken from normal areas in the surgically resected kidney from patients with renal cancer. STS activity was analyzed by enzyme histochemistry using 4-methylumbelliferyl sulfate. STS-mRNA distribution was detected by in situ hybridization using an STS cDNA probe cloned from human placenta.
Improvement of lysine effect on aldehyde-ruthenium red preservation and staining of the staphylococcal glycocalyx
Authors: Fassel Theresa A. , Mozdziak Paul E. , Sanger James R. , Edmiston Charles E. 
Published: June 2020

The cationic reagent ruthenium red (RR) has been used to enhance ultrastructural preservation and staining of the bacterial glycocalyx. Lysine was needed in prefixation to preserve the polysaccharide glycocalyx material for the gram-positive, coagulase-negative staphylococci species. The inclusion of lysine in the prefixative of glutaraldehyde (GA)-RR enhanced observation of elaborate and extensive glycocalyx material. However, prefixation in 75 mM lysine in GA-RR is restricted to 20 minutes because gelling or solidification frequently occurs at longer intervals resulting in loss of sample. To improve the utility of this approach, the effect of the Karnovsky ratio of 2% paraformaldehyde to 2.5% GA was investigated.Cells of gram-positive, coagulase-negative staphylococci species, Staphylococcus epidermidis RP62, a polysaccharide producer, and Staphylococcus epidermidis M187-SN3, a polysaccharide negative mutant, were recovered from frozen storage and grown on blood agar plates. After 24 hours, cells were transferred to trypticase soy broth for 18 hours, and incubated at 35°C. Half of the cells were prefixed in 75 mM L-lysine, 0.075% RR, 2.5% GA in 0.1 M sodium cacodylate pH 7.2 for 20 minutes.
Intensity attenuation of Three-Dimensional, confocal fluorescence images of thick tissue
Authors: Kayali S. , Ancin H. , Roysam B. , Shain W. , Szarowski D.H. , Turner J.N. 
Published: June 2020

The confocal scanning laser microscope (CSLM) provides three-dimensional (3-D) images from fixed tissues. These images are obtained by stacking consecutive confocal planes through the depth of a specimen. We have developed software for quantitative analysis of these data sets and have applied these methods to cell counting. A major issue in this analysis is the relative intensity of signal measured from like objects through the depth of the specimen.The rat hippocampus was chosen to test the attenuation of the fluorescence signal allowing us to make observations in areas of higher density-pyramidal cell layer-and lower density -extra-pyramidal regions. Paraformaldehyde fixed specimens were stained with Feulgen-Schiffs acriflavine. This stain was selected for its fluorescent properties and its high DNA specificity. Specimens were mounted in media with different glycerol concentrations. Significant attenuation was observed using a 50:50 mixture of glycerol and buffer, while 100% glycerol provided significantly less attenuation. All data presented here were collected using sections mounted in 100% glycerol. 3-D images were collected from 50-, 75-, and 100-μm thick sections with a 40x oil objective, having an (x,y) resolution of 2 pixels//xm and a distance of 1 fim between optical sections. Fig. 1 is a projection of a 100-μm section of the rat hippocampus illustrating pyramidal and extra-pyramidal areas.
3-D reconstruction from serial thick sections, with multiple-level profiling within stereo pairs, using the albany HVEM's “SSRECN” software
Authors: Marko M. , Banerjee R. , Leith A. , King M. , Radermacher M. , Frank J. , Parsons D. 
Published: June 2020

We have designed and written a program, SSRECN, for making 3-D reconstructions from contours in parallel planes. In our work with serial thick sections, we find a need to sample the object at multiple levels in depth, and we suggest a means for doing this.SSRECN was written with the biological electron microscopist in mind, and its capabilities cover all common requirements for such work. Additional features are added as special user needs come up. Special care was taken to make it “user friendly”; it is menu-driven, with liberal helps and explanations available on-line, and requires no prior computer experience or reading of documentation. Error traps prevent frustration due to accidental loss of data or program crashes. Its comprehensive and versatile database system provides for handling three-dimensional contour data (including depth connection instructions for reconstruction of branching structures) at all points in the program, both as single contours and as groups (i.e. individual contours of a single organelle and also those of a group of organelles of the same type).
Electron microscopy of frozen, hydrated lacrosse virus
Authors: Talmon Y. , Prasad B. V. V. , Clerx J. P. M. , Chiu W. , Hewlett M. J. 
Published: June 2020

LaCrosse (LAC) virus is a member of the California serogroup of the Bunyaviridae. The bunyaviruses are all negative-sense, RNA viruses whose genome consists of three segments of single stranded RNA. LAC virions are composed of multiple viral RNA strands complexed with viral nucleocapsid protein surrounded by a bilayer membrane embedded with 2 glycoproteins.Staining and drying of LAC virus samples produce images in which the virions are collapsed and distorted (Figure 1). Fixation prior to staining, also gives disappointing results, probably due to the high sensitivity of the LAC virus to changes in the ionic strength and composition of the solution in which it is suspended.