bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantification of axonally transported material using cytofluorimetric scanning
Authors: Dahlström A. , Kling‐Petersen T. , Bööj S. , Lundmark K. , Larsson P. A. 
Published: August 2011

SummaryThis paper describes in detail a cytofluorimetric scanning technique used for studying amounts of material axonally transported in antero‐ and retrograde direction in peripheral nerves. Operating procedures, preparation of tissues and instrumental set‐up are described. The basis for quantification of material in a nerve section treated for immunofluorescence is discussed. The reliability of the method has been tested by comparing results with biochemical data. There are several advantages of the technique. (1) Many different substances can be studied in one single nerve segment, thus reducing biological variation and costs. (2) Both morphological data and quantitative figures can be obtained; following scanning the section can be photographed. (3) The method can also be used on studies in the central nervous system and on tissue cultures, since it is possible to scan on single axons or bundles of fibres.
Scanning and detection techniques used in a confocal scanning laser microscope
Authors: Carlsson K. 
Published: August 2011

SUMMARYA two‐mirror scanning mechanism for confocal microscopy is described. No optical components, in addition to the scanning mirrors, are used. Design criteria and performance of the scanner are discussed. The photometric linearity of a detector unit incorporating a photomultiplier tube is reported, and a dual detector unit with tunable split wavelength is described.
A confocal video‐rate laser‐beam scanning reflected‐light microscope with no moving parts
Authors: Goldstein Seth R. , Hubin Thomas , Rosenthal Scott , Washburn Clayton 
Published: August 2011

SUMMARYA no‐moving‐parts, 30 frames/s, laser‐beam scanning confocal reflected‐light microscope has been developed. In principle, the technique can be extended to fluorescence and transmission light microscopy. Acousto‐optic beam deflectors controlled by digital electronics move a laser beam in a 512‐line interlaced 8·5 times 8·5‐mm raster. The light passes through a beam splitter, enters an inverted microscope through the side camera port, and is imaged at the object by the microscope objective. Reflected light returns through the objective, exits the camera port, is reflected off the beam splitter, and is imaged on to the photocathode of an image dissector tube (IDT). Confocality is provided by raster scanning the IDT aperture coincident with the congruent image of the laser beam incident on the object. Real‐time jitter‐free reflected light images of a variety of biological objects have been produced. Computer‐controlled alignment of the laser scan and IDT is performed in several seconds.
Positron emission tomography—a new technique for studies of the central nervous system
Authors: Eriksson Lars , Dahlbom Magnus , Widén Lennart 
Published: August 2011

SUMMARYPositron emission tomography (PET) has become an important tool to study the central nervous system. Examples of such studies are cerebral blood flow and metabolism and determination of receptor characteristics of the brain. In the following the basic principles and the physics behind PET are given. Different aspects are discussed such as detector design, image reconstructions and data analyses. Since quantification is essential in PET, data have to be corrected for absorption, scatter and random coincidences. These corrections and their influence on image data are discussed.A review of state‐of‐the‐art PET research of the brain is given.
A quantitative approach to cytoarchitectonics: Analysis of structural inhomogeneities in nervous tissue using an image analyser
Authors: Schleicher Axel , Zilles Karl 
Published: August 2011

SUMMARYCytoarchitectonic investigations are based on the analysis of structural inhomogeneities in the neuronal composition of nervous tissue. Boundaries of brain regions are established at locations where local structural properties, such as density, shape, orientation or arrangement of the nerve cells, change. A quantitative approach requires a complete scanning of histological sections and the measurement of at least one of these properties using an automatic device. In contrast to recently developed stereological methods which result in unbiased estimates of parameters and which are based on efficient sampling procedures, measurements with automatic devices are biased due to section thickness and problems in the segmentation of nerve cell bodies. Automatic measurements are necessary, however, if a complete scanning of histological sections is required in order to localize areal or laminar boundaries. In this approach, the grey level index (GLI) is measured with a TV‐based image analysing system from routine histological sections. Using Nissl‐staining, this parameter is a biased estimate of the local volume density of Nissl‐positive structures (cell bodies). The histological section is digitized into a GLI image by a scanning procedure. The GLI image is processed by image enhancement procedures in order to visualize the laminar pattern. Areal boundaries are localized at positions where this laminar pattern changes. GLI statistics of single brain regions can easily be evaluated by delineating these regions with a cursor in the GLI images of the sections. Information from a series of sections is compiled by specific application programs.
A rapid preparation technique for leucocytes
Authors: McCarthy D. A. , Bernhagen J. , Liu Y‐C. , Perry J. D. 
Published: August 2011

SUMMARYA procedure is described for making leucocyte preparations from blood samples fixed ex vivo. Briefly, blood is treated with buffered formaldehyde and the erythrocytes and platelets removed subsequently by lysis and differential centrifugation. The fixed leucocyte preparations can then be processed or fixed further for various types of microscopy as required. In stained preparations examined by light microscopy, the different leucocytes, i.e. lymphocytes, polymorphonuclear leucocytes (PMN) and monocytes, can readily be identified by their characteristic nuclear morphology, and polarized PMN can easily be recognized by their non‐spherical shape. Experiments with chemotaxins in vitro indicated that the procedure could be used to determine whether polarized PMN circulate in the blood of normal individuals and patients with inflammatory disease. A study of the blood from eleven normal subjects showed that 84.0 ± 10.8% (mean ± 2 SEM) of circulating PMN were spherical, while the majority of the remainder (14.3 ± 10.5%) were only ‘slightly’ polarized.
Carbon‐based immunocytochemistry
Authors: Baigent C. L. , Müller G. 
Published: August 2011

SUMMARYA carbon‐based immunocytochemistry (CarBIC) method, whereby the epoxy resin is completely removed from a section prior to immunocytochemistry (IC), is described. The resulting absence of embedding medium allows for an optimal access of both primary antibodies and marker systems to structures at various levels throughout the depth of the section. A carbon film evaporated onto the surface of the section before extraction of the resin forms a base to which the section adheres and maintains structural integrity during subsequent processing. The conventional and accepted electron microscopical (EM) appearance for epoxy‐resin‐embedded material is regained by re‐embedding in Epon before contrasting in the normal manner. The technique is demonstrated using human cytomegalovirus (HCMV)‐infected human fibroblasts. HCMV+ serum is the source of primary antibodies and 10‐nm protein A‐gold (pA‐G10) together with rabbit anti‐human IgG + IgM is the marker for IC.
Preparation of the nematode‐trapping fungus, Arthrobotrys oligospora, for scanning electron microscopy by freeze substitution
Authors: Wharton D. A. , Murray D. S. 
Published: August 2011

SUMMARYA freeze‐substitution technique for preparing fungal specimens for scanning electron microscopy is described. This involves cryofixation in liquid nitrogen, freeze substitution in methanol at — 20°C and critical‐point drying. The trapping complexes and conidiophores of the nematophagous fungus Arthrobotrys oligospora are well preserved and retain their normal three‐dimensional arrangement.
Three‐dimensional reconstruction of a plant dictyosome from series of ultrathin sections using computer image processing
Authors: Lockhausen Jürgen , Kristen Udo , Menhardt Wido , Dallas William J. 
Published: August 2011

SUMMARYA single dictyosome from an actively secreting ovary gland cell of Aptenia cordifolia has been reconstructed in 3‐D from a series of twenty‐nine electron micrographs by computer image processing. The reconstruction is presented under different viewing angles in the form of shaded perspective displays. From these displays the entire dictyosome, surrounded by numerous vesicles, appears to be more a spherical than a flat body. The plate‐like region of the dictyósome is demonstrated when only a portion of the electron micrographs is used for the image processing, leading to ‘cut‐off’ displays. Since some upper planes were removed, such ‘cut‐off’ displays revealed both tubular connections between cisternae of the dictyosome and the neighbouring endoplasmic reticulum as well as tubular continuities between adjacent Golgi cisternae within the same stack. Possible consequences of both types of interconnections on transport and processing of proteins and glycoproteins are discussed.
Confocal microscopy as a tool for the study of the intranuclear topography of chromosomes
Authors: van Dekken H. , van Rotterdam A. , Jonker R. , van der Voort H. T. M. , Brakenhoff G. J. , Bauman J. G. J. 
Published: August 2011

SUMMARYA scanning confocal microscope was used to investigate the spatial positions of specific regions within blood cell nuclei. These centromeric regions were fluorescently labelled by in‐situ hybridization to suspended nuclei with a centromere‐1‐specific DNA probe. The 3‐D image data sets, obtained by optical sectioning of the cells, were used to determine the spatial position of the centromeric regions in the nuclei by means of specially developed software. The centromeres were found to be localized near the nuclear boundary. This spatial pattern was tested against a random distribution model by means of the Kolmogorov—Smirnov test. The difference between the two patterns was at a P < 0ċ01 significance level.
Confocal fluorescence microscopy: some applications in bone cell biology
Authors: Jones S. J. , Taylor M. L. 
Published: August 2011

SUMMARYThree‐dimensional information is necessary for the proper investigation of the interrelationships of bone cells, and of the complex interface between these cells and the bone matrix they form and destroy. The use of fluorescence confocal microscopy was explored in the determination of the distribution of immunolabelled actin and vinculin—cytoskeletal and attachment proteins—in isolated chick bone cells cultured on dentine, and in neonate rat and rabbit calvaria. Confocal imaging, compared with conventional fluorescence imaging, greatly enhanced the interpretation possible.
In vitro confocal imaging of the rabbit cornea
Authors: Masters Barry R. , Paddock Stephen 
Published: August 2011

SUMMARYWe were able to observe in vitro the fine structure of the rabbit cornea using a laser scanning confocal microscope, especially in the regions between Descemet's membrane and the epithelial basal lamina. We observed submicrometre filaments throughout the stroma with high concentrations adjacent to Descemet's membrane, and found extensive interconnecting processes between stromal keratocytes. There are numerous regions containing nerve plexuses in the stroma. We found a deeply convoluted basal lamina adjacent to the epithelium, and observed regions containing junctions between endothelial cells in fluorescent images of rabbit corneas stained with the actin‐specific compound fluorescein phalloidin.
Microwaves for microscopy
Authors: Kok L. P. , Boon M. E. 
Published: August 2011

SUMMARYSample preparation for microscopy is based on physical and chemical processes. These processes can be influenced by microwave irradiation. The prerequisite for the development of good microwave procedures is knowledge of histochemistry combined with understanding of the physics of microwave irradiation. Examples of superior results of fixation, processing, and (immuno) staining performed in the microwave oven are presented, both for light‐ and electron microscopy.
Fine structure of unstained human chromosome fibres dried with no fixative as observed by X‐ray contact microscopy
Authors: Shinohara K. , Nakano H. , Kinjo Y. , Watanabe M. 
Published: August 2011

SUMMARYX‐ray contact microscopy was used to examine unstained human chromosomes dried without any fixative. This is the first report of the observation of single human chromosome fibres at high resolution without any modification(s) such as staining or fixation. The ‘beads‐on‐a‐string’ structure was observed in stretched portions of chromosome fibres. The diameters of the thin filaments and small particles were 7–15 nm (mean ± SD of 12·2 ± 2·1 nm) and 16–69 nm (31·4 ± 13·2 nm), respectively. These sizes correspond to those of fibres composed of nucleosomes (10–15 nm in diameter) and particle units (15–50 nm in diameter) called superbeads (unit structures composed of a multiple association of nucleosomes). These results are in good agreement with the current nucleosome and superbead model for chromosome fibre structure.
Ultrastructural localization of nucleic acids in plant tissues following the use of malachite green or neutral red in the fixative solution
Authors: Lawton June R. 
Published: August 2011

SUMMARYMalachite green and neutral red, when added to glutaraldehyde for fixation of various tissues, yielded high‐contrast images of cell ultrastructure. Malachite green, in acid conditions, appeared to increase contrast of heterochromatin material in the nucleus whereas neutral red gave greater clarity to the nucleolus and to cytoplasmic ribosomes. Control tissue fixed under acid conditions showed little damage but there were ‘crystalline’ areas at the periphery of the nucleolus. RNase did not digest cytoplasmic ribosomes from tissue after neutral red glutaraldehyde fixation. These results suggested that neutral red became bound to RNA in the tissues. Fixation with malachite green, at a pH below 6, did not affect the digestion of RNA by RNase but did protect chromatin against the bleaching action of the chelating agent EDTA. The addition of malachite green (pH < 6) or neutral red to glutaraldehyde are useful techniques for the investigation of the ultrastructure of nuclear material and cytoplasmic ribosomes.
Cooling rate and ice‐crystal measurement in biological specimens plunged into liquid ethane, propane, and Freon 22
Authors: Ryan K. P. , Bald W. B. , Neumann K. , Simonsberger P. , Purse D. H. , Nicholson D. N. 
Published: August 2011

SUMMARYSpecimens sandwiched between copper planchettes were plunged up to a depth of 430 mm into coolants used for cryofixation. Hydrated gelatin containing a miniature thermocouple was used to mimic the behaviour of tissue during freezing. Gelatin and red blood cells were used for ice‐crystal analysis. Ethane produced the fastest cooling rates and the smallest ice‐crystal profiles, and Freon 22 produced the slowest cooling rates and the largest crystal profiles. Smaller crystal profiles were often seen in the centre of the specimens than in subsurface zones. The results show that ethane, rather than propane, should be used for freezing metal‐sandwiched freeze‐fracture specimens by the plunging method, and probably also in the jet‐cooling method. They further suggest that good cryofixation could occur at the centre of thin specimens rather than only at their surfaces. Comparison between theoretical and experimental ice‐crystal sizes was satisfactory, indicating that where the experimental parameters can be defined then realistic predictions can be made regarding cryofixation results.
The value of assessing cell proliferation in breast cancer
Authors: Lawry J. , Giri D. , Rogers K. , Duncan J. L. 
Published: August 2011

SUMMARYUsing three methods to measure cell proliferation, namely DNA cell cycle; anti‐proliferating cell monoclonal antibody (MAb) (Ki67, P145) analysis by flow cytometry; and the histological silver (argyrophilic) staining technique to visualize nuclear‐organizing regions (AgNOR), twenty‐two paired samples of primary breast tumour and axillary lymph node were analysed. The results showed variable levels of correlation between the methods used for the tumour group (r = 0.915, P <0.001 for Ki677 versus P145; r = 0.42, P <0.005 for percentage S/G2/M‐phase versus P145; r = 0.16, P <0.5 for percentage S/G2/M‐phase versus AgNOR; r = 0.400, P < 0.1 for Ki67 versus AgNOR). The lymph‐node group showed slightly poorer correlations, yet involved nodes showed a consistently higher level of proliferation than non‐involved nodes by all methods used.Overall, MAb binding of Ki67 or P145 was seen to be a good indicator of cycling cells, detecting G1‐phase cells in addition to S/G2/M‐phase cells indentified by the other methods used. However, no advantage was found over the usual DNA flow cytometric analysis of cells, which had clear prognostic value. AgNOR scores were found to be able to discriminate between diploid and aneuploid; and dividing and non‐dividing cells, but areas of score overlap limited the application of this technique to that of a positive discriminator only.
A variable‐thickness., multipurpose culture chamber for high‐magnification observation
Authors: Braga P. C. 
Published: August 2011

SUMMARYA new, versatile, general‐purpose, high‐magnification perfusion chamber for ex vivo microscopy, which can be machined at low cost, and which can be assembled very rapidly, is described. An additional useful feature is the special lock system, with an annular threaded screw tap with the inside wall cut to fit against the slant of the microscope objective, to increase the field of observation.
Acoustic microscopy of rocks
Authors: Rodriguez‐Rey A. , Briggs G. A. D. , Field T. A. , Montoto M. 
Published: August 2011

SUMMARYAcoustic images of two common rocks, granodiorite and limestone, are studied to explore the kind of geological information that they can provide. The contrast is primarily due to Rayleigh waves; in rock specimens they are mainly affected in their propagation by crystal anisotropy and surface discontinuities. Therefore, acoustic microscopy makes possible detailed identification of intragranular structures in the rock‐forming minerals (very fine cracks, grain and subgrain boundaries, etc.); these features may appear more sharply than in transmitted polarized light microscopy or in scanning electron microscopy. In particular the acoustic images are effective in microfractographic studies, they can show not only the finest cracks, even those much less than a wavelength wide, but also their position in relation to the grain and subgrain structure.
Biological cryosection preparation and practical ion yield evaluation for ion microscopic analysis
Authors: Sod Earl W. , Crooker Allen R. , Morrison George H. 
Published: August 2011

SUMMARYA mounting method utilizing an indium substrate is described for preparing freeze‐dried cryosections of biological tissue for ion microscopic analysis. Using this procedure, a qualitative comparison between cryosection, conventional chemical, and freeze‐substitution specimen preparations is made with rat liver tissue. Practical ion yield variations in cryosections are found to be minimal (± 13% relative standard deviation) in tissue‐containing areas of rat liver and small intestine.
Measurement of boundaries using a digitizer tablet
Authors: Mercer Robert R. , Randell Scott H. , Young Stephen L. 
Published: August 2011

SUMMARYThe perimeter is the most error prone of the primary measurements (length, perimeter and area) made when using a device such as a digitizer tablet to trace profiles on micrographs. To allow for minimization of this error an expression is developed relating the error in the perimeter to the digitizer resolution plus other errors in the entry process. The predictions of this expression are shown to be in good agreement with the results of computer simulation of the tracing process, as well as results from manual tracing using a digitizer tablet. This analysis of the digitizer entry process also provides a method by which an optimal choice of the sample spacing between digitizer coordinates can be made.
Occupational risks of (meth)acrylate compounds in embedding media for electron microscopy
Authors: Tobler M. , Freiburghaus A. U. 
Published: August 2011

SUMMARY(Meth)acrylates are the main constituents of embedding media widely used in electron microscopy research for low‐temperature embedding of biological tissue. (Meth)acrylates toxicology is still incompletely understood and therefore an estimation of health hazards involved in handling must be inaccurate. (Meth)acrylate monomers are known to be harmful to skin and other tissues and may sensitize workers. Since low‐temperature electron microscopy techniques have gained popularity in research laboratories, it is important to establish safety rules for handling the (meth)acrylate‐containing solutions.The aim of our report is to review briefly the toxicological properties and occupational hazards of the chemicals involved, summarize our own experiences with resins and protective devices in this respect, give guidelines for safe embedding and pass on these data to all interested researchers in order that workers are not discouraged from using (meth)acrylate embedding media, but know the risks and how to minimize them.
A revisionist history of microscopical sciences
Authors: Phinney Harry K. 
Published: August 2011

SUMMARYIndices of productivity have been constructed using the scientific literature of the seventeenth through mid‐nineteenth century for use in judging the accuracy of generalized statements citing low or no productivity in microscopical science during this time. The evidence produced refutes the expressed opinions that: (1) microscopes of that period were considered useless for scientific studies; (2) microscope images were considered unreliable by the scientific community; (3) the trivial activities of ‘amateurs’ precluded serious studies by ‘professionals’; (4) the microscope was simply unappreciated as a research tool until the middle of the nineteenth century.
Visualization and coding in three‐dimensional image processing
Authors: Forsgren Per‐Ola 
Published: August 2011

SUMMARYA system for calculating orthographic views of three‐dimensional objects from a confocal microscope has been implemented in a high‐level language. It is used on a regular basis in a number of projects and on different computers. The system enables the user to filter the original data and make a selection of which points and parts of the objects to show in a projective view. The information to be shown is coded in a compact format that is well suited for projection calculations. Several display principles were implemented that enhance different aspects of the objects.
Measuring the forces acting during microtomy by the use of load cells
Authors: Allison Russell T. , Vincent Julian F. V. 
Published: August 2011

SUMMARYThe forces acting upon the cutting blade during microtomy can be accurately measured by using a load cell. From the information obtained, the optimal knife angles (rake, clearance and slant) can be determined. In addition, the speed of cutting and thickness of sections can also be optimized. The information obtained from the load cell additionally reveals variations in tissue composition which affect the cutting forces. This paper is a preliminary communication to illustrate the possible roles for a modified microtome in (a) the study of microtomy and (b) comparative studies of tissue density.