bluuebunny/crossref_metadata_2025_split huggingface dataset:
A potassium permanganate fixative for membranes in sections
Authors: Song Jindan 
Published: June 2020

Potassium permanganate has been used as a fixative for the botanical specimen and membrane system in thin section by Glauert (1975). A new potassium permanganate fixative ( Trisodium citrate 60mM, Potassium chloride 25mM, Magnesium chloride 35mM, and Potassium permanganate 125mM ) for localizing membranous system in whole_mount cultured cells with standard trasmission electron microscopy and phase_contrast microscopy has been developed). Here, we report that using this new potassium permanganate fixative for membranous system in sections.Cultured cells, CV_1 (African green monkey kidney epithelial cells), Balb/c 3T3 ( Mouse embryo fibroblast ) and MCF_7 (Human adenocarcinoma cell line) were used for this study. All cells were grown on 35mm plastic dishes in DME medium containing 5% calf serum at 37 c with 100% humidity and 5% CO2. Using the potassium permanganate fixative to fix the cells for about 7 minutes. After fixation, the cells were dehydrated in a graded series of ethanol.
Uranyl acetate staining under different conditions of preparation, storage and use
Authors: Cross R.H.M. , Hodgson A.N. , Bernard R.T.F. 
Published: June 2020

Uranyl acetate is routinely used in the staining of thin sections of biological tissue for transmission electron microscopy. Although many methods for its preparation and use have been described, there is seldom reference to the reasons for variations in concentration, solvent, storage time and staining time. Likewise, possible variations in the effects of staining under different conditions are largely ignored. In order to gain clarity on this issue an attempt has been made to test three variables (solvent, storage time and use in light or dark) under controlled experimental conditions.The tissues used for the experiment were the testis of a marine limpet, the gut epithelium of a fresh-water catfish, and the kidney of a rat; all of which were fixed and embedded by standard methods. The uranyl acetate solutions were prepared at the outset of the experiment and dispensed into small volumes and stored in the dark at 4°C until required.
A Scanning Electron Microscopy study of laser-cut hair
Authors: Hess W. M. , Gardner John S. , Srinivasan R. , Braren Bodil 
Published: June 2020

Ablative photodecomposition with an ultraviolet laser was used for making clean holes in organic polymers. The purpose of this study was to determine whether similar procedures could be used to cut hair. Cross-sections of hair makes it possible to characterize shape and size of human and animal hair. The use of a laser provides a means to control the angle of cut and a means to cut hair without applying pressure to the hair shaft, preventing shape distortion. Then accurate cross sectional measurements can be obtained for area and perimeter determinations.The laser was filled with argon and fluorine with helium as a buffer gas. The emitted pulses had a wavelength of 193 nm. The beam was narrowed by passage through a convex lens made of fused quartz. The intensity was 200 millijoules/sq.cm. and cutting was done in air. The greater the fluence the greater the depth of removal per pulse.
Detection of mRNAGFAP by post-embedding EM in situ hybridization
Authors: Erickson Page A. , Feinstein Stuart C. , Lewis Geoffrey P. , Fisher Steven K. 
Published: June 2020

We have developed a technique that allows mRNA molecules to be localized within cells at extremely high (nanometer) resolution. Using a cDNA for glial fibrillary acidic protein (GFAP forms lOnm diameter intermediate filaments), we have localized the mRNAGFAP in three different cell types (optic nerve astrocytes, retinal astrocytes and retinal Miiller cells). One retina was experimentally detached to stimulate GFAP expression in retinal Miiller cells. Cells containing GFAP were identified by immunoelectron microscopy. Cat retinas and optic nerves (n=7) were fixed with 2% or 4% paraformaldehyde for 1.0 hr, dehydrated with dimethylformamide, and embedded in Lowicryl K4M resin. Thin sections, placed on nickel grids, were probed with biotinylated cDNAGFAP (overnight at 37°C) followed by streptavidin-gold conjugate (1.0 hr, 23°C).In each of the three cell types that contain GFAP, the localization of the mRNAGFAP was the same. In the nuclei gold spheres were localized over amorphous, electron-dense regions within the euchromatin (presumably precursor mRNA).
A technique for the study of histozoic myxosporean cysts: SEM of faces of partially cut wax embedded blocks
Authors: Odense Paul , Cone David 
Published: June 2020

Myxosporeans include many histozoic protist parasites of fishes in freshwater and marine environments worldwide and in a number of systems constitute important pathogens. Most species produce trophozoites that form obvious and often grotesque, cyst-like structure s within the host tissue. Traditionally, these trophozoites have been studied by means of either light or transmission electron microscopy. We have developed a simple technique whereby SEM can be used to supplement traditional light microscopical observations.Specimens of Myxobolus lamellus Grinham and Cone, 1990 were chosen because of the unusual nature of the trophozoite cyst, which is compartmentalized instead of the hollow fluid-filled sac typical of most species. The material was collected from the secondary gill lamellae of Catastomus commersoni living in a small lake in south shore Nova Scotia, 45 km west of the city of Halifax. Live fish were transported to the laboratory and necropsied. Cysts were fixed in 10% neutral buffered formalin for several days before being dehydrated and embedded in Paraplast using routine histological techniques.
Detection of human cytomegalovirus infection in paraffin sections by Grocott’s methenamine silver stain for light and electron microscopy
Authors: Chien K. , Kim Y.K. , Shintaku I.P. , Van de Velde R.L. , Heusser R.C. , Danao F. , Geller S.A. 
Published: June 2020

Grocott's methenamine silver stain (GMS) has been used histologically for identifying Pneumocystis carinii and fungal infections in paraffin sections of surgical specimens. However, current studies indicate that aggregates of human cytomegalovirus (HCMV) in the cytoplasm of infected cells are also stained by GMS and can be detected by LM. Since precipitated silver particles are electron dense, the presence of silver labelled HCMV virions can be easily located and confirmed by TEM.GMS and light green stained paraffin sections positive for HCMV can be processed for TEM either by conventional procedures or as follows: Coverslips are removed by immersion in xylene. A few drops of 1% 0s04, freshly dissolved in xylene, are then pipetted onto each slide for 5 minutes. Prolonged osmication is to be avoided as it will cause reduction of the silver deposits. Slides are then rinsed in xylene and changed to 100% acetone. Substitution of acetone for xylene prior to resin infiltration will produce a better quality block for sectioning. The sections are embedded, polymerized and subsequently separated from slides as previously described. The light green staining is retained in the epoxy block, which facilitates tissue orientation and selection of areas for thin-sectioning.
Neurotoxicity of manganese in the teleost Tilapia
Authors: Herrera Annabelle A. , Catap Elena S. 
Published: June 2020

Manganese is considered as an essential element for man and other animals. Although it is one of the trace elements least toxic to mammals, man-made pollution related to the steel industries and exposure to the mining of manganese ore represent potential hazards to organisms in these areas.One of the target organ systems of manganese is the central nervous system (Beliles, 1975). Intake of its metal dust can lead to chronic manganese poisoning resembling Parkinson’s disease (Ferraz, et.al., 1988). Symptoms of this disease have been observed in human after prolonged chronic exposure to manganese (Scheuhammer and Cherian, 1981).Studies being reported on manganese deal with mammals and are focused on its neurotoxicity, most of which are based on physiological and neurochemical mechanisms. There has been no report yet of morphological or ultrastructural abnormalities associated with manganese exposure. In this study, the effects of manganese on the morphology and ultrastructure of the brain of Tilapia finger lings will be discussed.Tilapia fingerlings from Central Luzon State University, Muñoz, Nueva Ecija were acclimated prior to MnCl2 exposure.
A simple method for exposing and examining the interior of fragile biological materials
Authors: Wasserman Arthur J. , Pedro Kato Y. , Silver Frederick H. 
Published: June 2020

Examining the inside of delicate and fragile dry biomaterials is difficult because they are vulnerable to mechanical damage. Compression and sheering of a sample during exposure of the interior can produce artifacts making interpretation of the ultrastructure difficult. In this report a simple method for exposing and retaining the interior substructure of delicate specimens and mounting them for scanning electron microscopic (SEM) observation is described.Collagen fibers were prepared as described previously. In brief, 1% collagen dispersion, prepared from bovine hide, was extruded through polyethylene tubing with an inner diameter of 0.28 mm into a 37°C, pH 7.5, fiber formation buffer. After 45 mins in the buffer, the fibers were rinsed in isopropyl alcohol for 4 hrs followed by distilled water for 20 mins. The fibers were then crosslinked.The interior of collagen fibers were exposed by deep freezing 1 cm segments of fiber in liquid nitrogen. Using iris scissors the first and last piece of each segment (which contained ends previously exposed to the atmosphere) were snapped away and discarded. Each frozen segment was then snapped in half. By this method each half of the original 1 cm segment had a freshly cleaved top and bottom surface. The segments were transferred to an aluminum foil pouch (in liquid nitrogen).
Ultrastructural observations on the in vitro cytoadherence of Plasmodium falciparum infected red blood cells
Authors: Ferguson D.J.P. , Berendt A.R. , Tansey J. , Marsh K. , Newbold C.I. 
Published: June 2020

In human malaria, the most serious clinical manifestation is cerebral malaria (CM) due to infection with Plasmodium falciparum. The pathology of CM is thought to relate to the fact that red blood cells containing mature forms of the parasite (PRBC) cytoadhere or sequester to post capillary venules of various tissues including the brain. This in vivo phenomenon has been studied in vitro by examining the cytoadherence of PRBCs to various cell types and purified proteins. To date, three Ijiost receptor molecules have been identified; CD36, ICAM-1 and thrombospondin. The specific changes in the PRBC membrane which mediate cytoadherence are less well understood, but they include the sub-membranous deposition of electron-dense material resulting in surface deformations called knobs. Knobs were thought to be essential for cytoadherence, lput recent work has shown that certain knob-negative (K-) lines can cytoadhere. In the present study, we have used electron microscopy to re-examine the interactions between K+ PRBCs and both C32 amelanotic melanoma cells and human umbilical vein endothelial cells (HUVEC).We confirm previous data demonstrating that C32 cells possess numerous microvilli which adhere to the PRBC, mainly via the knobs (Fig. 1). In contrast, the HUVEC were relatively smooth and the PRBCs appeared partially flattened onto the cell surface (Fig. 2). Furthermore, many of the PRBCs exhibited an invagination of the limiting membrane in the attachment zone, often containing a cytoplasmic process from the endothelial cell (Fig. 2).
Immunogold localization of fibrinogen (FIB) and its receptor on human platelets by conventional and intermediate-voltage EM (IVEM)
Authors: Hensler Mary E. , Hantgan Roy R. , Willard Andra S. , Lewis Jon C. 
Published: June 2020

Platelet aggregation involves fib, which serves as a molecular bridge within hemostatic plugs. The interaction of fib with platelets is mediated by glycoprotein IIb/IIIa (GPIIb/IIIa), which binds fib after platelet activation. Ultrastructural studies have documented relocation of GPIIb/IIIa with long-term activation. However, little is known about GPIIb/IIIa redistribution during early activation. Reported is the use of immunogold chemistry along with thick-section stereo IVEM and TEM stereology to document the location of fib and GPIIb/IIIa during early activation.Platelets were isolated from anticoagulated blood obtained following informed consent from human volunteers. Plasma proteins were removed by gel-filtration over Sepharose 2B in a Hepes-albumin-Tyrodes buffer. The gel-filtered platelets (GFP) were activated in suspension with 10 umol/L ADP in the presence of 2 mmol/L CaCl2 and in select experiments 100 μg/mL fib. GFP at various activation times were fixed in 1% glutaraldehyde, and the following monoclonal antibodies (mabs) were used to localize GPIIb/IIIa: P2 (AMAC, Inc.), AP-2 (provided by Dr. T. Kunicki), and 7E3 (an activation dependent mab from Dr. B. Coller).
Scanning probe microscopy: A new technology takes off
Authors: Elings Virgil 
Published: June 2020

With the expanding use of the scanning tunneling microscope, the technology is developing into other scanning near field microscopes, microscopes whose resolution is determined by the size of the probe, not by some wavelength. The first available “son of STM” will be the atomic force microscope (AFM), a very low force profilometer which has atomic resolution and can profile non-conducting surfaces. The hope is that this microscope may find more applications in biology than the scanning tunneling microscope (STM), which requires a conducting or very thin sample.In the past five years, the STM has progressed from curiosity to everyday lab tool, imaging surfaces with scans from a few nanometers up to 100 microns. When compared to an SEM, the STM has the advantages of higher resolution, lower cost, operation in air or liquid, real three-dimensional output, and small size. The disadvantages are smaller scan size, slower scan speeds, fewer spectroscopic functions and, of course, not as many of the nice features of the more mature electron microscopes. The AFM has similar features to the STM except that the detector and profiling tips are more complicated and more difficult to operate—disadvantages that will decrease with time.
Three Ways to Look at Muscle
Authors: Goldstein Margaret Ann 
Published: June 2020

A pictorial history of muscle morphology from the 1960’s to the 1990’s shows the successive addition of new methodology and the combination of analytical techniques with descriptive approaches. These powerful images express the relationships between the cell components required for cycles of contraction and relaxation.Although electron micrographs are used as pictures to illustrate a story, they are precise descriptions containing analyzable data. The vast quantities of information contained in a single image has been the impetus to make better procedures and technologies to extract and display selected information. One of the simplest methods of feature extraction that is still widely used is cropping images to limit the field of view. Selective staining allows visualization of long-range ordering of specific features in images from HVEM. Optical diffraction and optical reconstruction provide for enhancement of order, and stereological approaches allow for quantitation in studies of muscle protein lattices.
Generating and Comparing Three-Dimensional Images of Structures Obtained by Electron Microscopy and other Methodologies
Authors: DeRosier D. J. 
Published: June 2020

“Subtract the mind,…and the eye is open to no purpose, which before did see.” “Before my eye can see the painting on the wall, this must…be borne into my phantasy, to be assimilated by my understanding.” (both attributed to 14th century philosopher-mystic, Meister Eckhart).Images of models provide a way to look at structures. A well-executed model can embody the results of many studies in a way that our minds easily grasp. We learn from them, and we teach from them. They are especially important in structural studies because comprehension of spatial relationships is key to our understanding. The computer, with its ability to generate, color and animate three-dimensional objects, is a source of both good and evil when producing images of models.Models are really analogies intended to illustrate particular attributes of a structure. A “dangerous pitfall is hidden in the very nature of analogies themselves. Every grade [of analogy] can be traced between remote analogies, and analogies which are so close that they pass into identities, and – paradoxically enough – it is often the remote analogies which have the greatest value, while it is the close analogies of which we have to beware. The misuse of an analogy by pressing it to the point at which it is confused with an identity, is one to which biological thought is particularly liable.” (Agnes Arber, 1953).
The Impact of Imaging Technologies in Materials Engineering
Authors: Gronsky R. 
Published: June 2020

Materials Engineering is widely acknowledged as a “hyper-discipline” spanning the fundamental sciences (Physics, Chemistry and Biology) with all of the traditional engineering pursuits (Civil, Electrical, Mechanical, Metallurgical, Nuclear…). A healthy materials engineering program in fapt demands interaction among basic science and technology, all classes of materials, and the intrinsic elements of the field, parochially known as properties, performance, structure (including composition) and synthesis (including processing). Advanced characterization techniques are obviously critical to this integration, and new imaging technologies have accelerated the process of characterizing materials at all relevant length scales, communicating large data sets to practicing engineers, and refining manufacturing methods with image-based technologies. The importance of imaging technologies was forecast by the National Research Council in a highly regarded 1989 report “Material Science & Engineering for the 1990’s: Maintaining Competitiveness in the Age of Materials,” which included prominent mention of all microscopy methods. Since then, the success and challenges associated with imaging technologies have increased dramatically.In the biomaterials field, which is projected to be a $5 billion dollar industry before the year 2000, imaging technologies are most evident. Cross-modal medical imaging (MRI, CAT..) localizes the results of disease or trauma that might be remedied by implantable structures, developed under condition of strict microstructural control, and monitored for degradation products by non-invasive in-situ means. Products include biochemical sensors requiring high spatial resolution characterization of structure and composition, orthopedic prostheses and repairs, sometimes processed to possess pore structures that mimic natural bone, and wound-management devices, including artificial skin composed of bi-layer silicone elastomers and glycosaminoglycan interspersed with collagen. The last of these is especially dependent upon microstructural characterization. Implantable materials systems, such as the cochlear implant for hearing restoration (direct stimulation of the auditory nerve), or heart-assist devices (long fatigue life), require some of the highest standards in materials selection, design, and integration, with the added dimension of biocompatibility. In addition, the irradiation sensitivity of many candidate biomaterials requires strict attention to low-dose imaging methods, rapid scan image acquisition, and sometimes extensive image processing to avoid or circumvent artefacts. Forward-looking projects on fully implantable therapeutic “agents” for medicinal delivery or chelation of toxins and viruses will place even more demands upon our ability to image in-situ functionality.
In Situ Localization of PPAR Gamma and Uncoupling Protein in Mouse Embryo Sections Using Digoxigenin-Labeled Riboprobes
Authors: Jennermann C. , Kliewer S. A. , Morris D. C. 
Published: June 2020

Peroxisome proliferator-activated receptor gamma (PPARg) is a member of the nuclear hormone receptor superfamily and has been shown in vitro to regulate genes involved in lipid metabolism and adipocyte differentiation. By Northern analysis, we and other researchers have shown that expression of this receptor predominates in adipose tissue in adult mice, and appears first in whole-embryo mRNA at 13.5 days postconception. In situ hybridization was used to find out in which developing tissues PPARg is specifically expressed.Digoxigenin-labeled riboprobes were generated using the Genius™ 4 RNA Labeling Kit from Boehringer Mannheim. Full length PPAR gamma, obtained by PCR from mouse liver cDNA, was inserted into pBluescript SK and used as template for the transcription reaction. Probes of average size 200 base pairs were made by partial alkaline hydrolysis of the full length transcripts. The in situ hybridization assays were performed as described previously with some modifications. Frozen sections (10 μm thick) of day 18 mouse embryos were cut, fixed with 4% paraformaldehyde and acetylated with 0.25% acetic anhydride in 1.0M triethanolamine buffer. The sections were incubated for 2 hours at room temperature in pre-hybridization buffer, and were then hybridized with a probe concentration of 200μg per ml at 70° C, overnight in a humidified chamber. Following stringent washes in SSC buffers, the immunological detection steps were performed at room temperature. The alkaline phosphatase labeled, anti-digoxigenin antibody and detection buffers were purchased from Boehringer Mannheim. The sections were treated with a blocking buffer for one hour and incubated with antibody solution at a 1:5000 dilution for 2 hours, both at room temperature. Colored precipitate was formed by exposure to the alkaline phosphatase substrate nitrobluetetrazoliumchloride/ bromo-chloroindlylphosphate.
Can Microwave Ovens Reduce Immunocytochemical Labeling Times?
Authors: Iadarola Linda , Webster Paul 
Published: June 2020

In recent years the use of microwave ovens in biomedical microscopy laboratories has contributed to reducing the times of fixation and resin embedding. Reports of the use of microwaves for histochemsitry and immunocytochemistry led us to investigate the possible use of a microwave oven to reduce immunocytochemical labeling protocols.The application of specific antibodies to thawed cryosections of aldehyde-fixed material is becoming more accessible to research and service laboratories. These detection methods, routinely performed in our laboratory, were used to study the effect of microwaves on labeling protocols using affinity purified, polyclonal antibodies and protein A-gold.Cells containing 3-(2,4-dinitroanilino)-3-arnino-N-methyldipropylamine (DAMP), a compound which accumulates in low pH compartments, were aldehyde-fixed, cryosectioned and then labeled with rabbit antibodies to dinitrophenol (which bind to DAMP) and 10nm protein-A gold. Regular sequential labeling protocols were compared with protocols using a microwave oven operating at 100% power, where the antibody incubation and washing times were reduced. The effect of microwaves on the labeling efficiency was investigated using simple quantitative methods. The protocol which produced reduced incubation times with no loss of labeling efficiency was then applied to sections in the absence of microwaves. The effect of reducing the final methyl cellulose-uranyl acetate contrasting step was also investigated.