bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adaptation of a low‐power stereomicroscope to scan cell colonies labelled with fluorescein isothiocyanate
Authors: McMahon James B. , Iype P. Thomas 
Published: August 2011

SUMMARYA stereomicroscope was modified for use in visualizing fluorescence‐labelled cell‐colonies at low magnifications. A xenon lamp and an FITC filter (Zeiss) were used to obtain exciting radiation to illuminate fluorescent‐labelled specimens. The system is precise enough to distinguish between normal and cancer cell‐colonies after specific interaction with FITC‐conjugated antiserum.
An improved technique for the freeze‐fracture of cell cultures grown as monolayers
Authors: Umrath W. 
Published: August 2011

SUMMARYAn improved and rapid procedure for the freeze‐fracture of cell cultures grown as monolayers is described. No additional equipment than normally used for freeze‐fracturing is necessary and cell culture conditions are as usual on plastic dishes. Cells are grown on a plastic foil membrane so that they can be viewed with a light microscope. If necessary, while viewing with a binocular microscope, specimen holders are glued to the foil membrane over selected areas of the culture. The specimen holders with the attached cell culture are dissected out and processed for freeze‐fracturing in a BIOETH 2005. Fracture planes occur along the cell surface as well as through entire cells. Analysis of corresponding fracture faces is possible.
Vicia faba root slices examined after freeze‐fracture and thaw‐fixation
Authors: Haggis G. H. 
Published: August 2011

SUMMARYVicia faba root slices have been frozen, fractured and thawed into fixative, to give a deep view into cell cytoplasm and into cell organelles. Fracture through interphase nuclei shows a tangle of 20–25 nm chromatin as well as finer strands. The nucleoli appear very compact. The proplastids in these preparations are packed with starch grains. In fracture through smaller organelles, probably mitochondria, 10–12 nm strands are seen which may correspond to organelle DNA in supercoiled form. Strands of this dimension, as well as finer strands, are also seen in preparations of isolated leaf chloroplasts after freeze‐thaw lysis.
The design and use of a simple device for rapid quench‐freezing of biological samples
Authors: Handley Dean A. , Alexander Jack T. , Chien Shu 
Published: August 2011

SUMMARYThe detailed design of a simple device for rapid quench‐freezing of biological samples under reproducible conditions is presented. With spring‐augmented descent, sample immersion velocity of 10 m s−1 into a cryogenic liquid is achieved. Biological samples, loaded in Balzers planchets, Denton holders, or a newly designed ‘titanium envelope’, are suitable for rapid‐freezing with this device. Using 4 μm titanium foil, light weight (1 mg) streamlined holders can easily be made to enclose cell suspensions or tissue samples. The foil envelope is designed for efficient heat dissipation while protecting the sample from possible impact or flow distortions occurring from spring‐augmented immersion. Human erythrocytes, quench‐frozen in the titanium envelope, were prepared for electron microscopy by the freeze‐substitution technique. Two opposing 25–30 μm surface zones were frozen in the apparent absence of ice. The extended depth of cryofixation is attributed to the advantages of thin foil in the titanium envelope design and the use of rapid‐immersion technique.
Polyvinyl alcohol coating: an improvement of the freeze‐fracture technique
Authors: Brown Dennis 
Published: August 2011

SUMMARYA modification of the freeze‐fracture technique, involving the coating of tissues with polyvinyl alcohol (Vinol) prior to freezing, is described. This results in substantial improvements over the more conventional method in which material is cryoprotected and frozen in buffered glycerol alone. The high vacuum is produced more rapidly and can be better than in the absence of vinol and the speed of replica recuperation is greatly increased.
Estimation of surface labelling on whole, critical point dried, cells by microprobe analysis in the scanning electron microscope
Authors: ap Gwynn I. 
Published: August 2011

SUMMARYA method is described whereby the relative amount of histochemical label, such as ferritin, provided it is exclusively attached to the surface of cells, can be estimated. The X‐ray emission from the metal coating, deposited from a diode‐sputter coating unit, is used to correct for the variations in the iron counts from the label which could occur due to changing analysis conditions.
Microdensitometry with image analyser video scanners
Authors: Jarvis L. R. 
Published: August 2011

SUMMARYA numerical method for calibration of the Quantimet 720 1D Auto detector as a densitometer in absolute density units has been developed and applied to integrated microdensitometric measurement. A procedure for the estimation and correction of microscope glare error has also been derived. The error after glare correction was found to be comparable with threshold setting variation encountered in routine use of the Quantimet.The method should prove valuable in densitometric applications not only for Quantimet image analysers but also for any instrument employing a video imaging system because the underlying principles are the same.
On the relative efficiencies of alternative ratio estimators for morphometric analysis of cell membrane surface features
Authors: Mayhew T. M. 
Published: August 2011

SUMMARYFor morphometric analysis of desmosomes, synapses and other membrane surface features, estimating component densities on a reference surface (the membrane with which they are associated) often provides a useful practical alternative to estimating densities in a reference volume (the tissue in which they are enclosed). The present report assesses the relative efficiencies of these two approaches. In particular, the efficiencies of stereological estimators for component numerical density on a surface (Ns) and in a volume (Nv) are compared, together with those for the surface densities Ss and Sv.For this purpose, a morphometric model developed for characterizing desmosomes in human forearm skin was quantified by point and intersection counting. The efficiencies of the alternative ratio estimators were evaluated by comparing their coefficients of variation obtained on samples of equivalent size and having a similar overall analysis time. Various types of bias influencing the results are also discussed.The results demonstrate that estimators of component densities on a surface are superior to those of densities in a volume when studying epidermal desmosomes. For a given size of sample they offer a smaller coefficient of variation. In other words, they are more efficient. They may be even more advantageous in other experimental situations.
Three‐dimensional reconstruction from images of tilted specimens: the paramyosin filament
Authors: Dover S. D. , Elliott A. , Kernaghan A. K. 
Published: August 2011

SUMMARYThe three‐dimensional structure of the paramyosin filament has been reconstructed from images obtained when the specimen is tilted at different angles about its long axis. The micrographs were correlated spatially using gold marker beads and digitized. The different views contained in each micrograph were combined using a computational technique involving Fouri***er transforms and the resulting three‐dimensional images are presented as various sets of serial sections. The results confirm that the Bear‐Selby (1956) net can be seen at all levels in the specimen.
Morphometric studies on mouse bone using a computer‐based image‐analysis system
Authors: Green D. , Howells G. R. , Thorne M. C. 
Published: August 2011

SUMMARYThe morphological structure of the ilium, femur, third lumbar vetrebra and a central caudal vertebra of the female CBA mouse has been studied using 5 μm thick, plastic embedded, transverse and longitudinal sections. The sections were analysed on a Quantimet 720, system 30, image analyser connected on‐line to a PDP11 computer. Separate endosteal and periosteal surface to volume ratios were calculated for each position of sampling in each bone. For this calculation the anisotropy of the bone was estimated from measurements of mean chord lengths in longitudinal sections of the bone using a new analytical technique. Chord length distributions in transverse sections of bone were also measured and the relevance of such measurements to the study of morphological changes in the bone and its included marrow are briefly discussed.
The use of a computerized algorithm to determine single cardiac cell volumes
Authors: Marino Thomas A. , Cook Larry , Cook P. Nong , Dwyer Samuel J. 
Published: August 2011

SUMMARYSingle cardiac muscle cell volume data have been difficult to obtain, especially because the shape of a cell is quite complex. With the aid of a surface reconstruction method, a cell volume estimation algorithm has been developed that can be used on serial sections of cells. The cell surface is reconstructed by means of triangular tiles so that the cell is represented as a polyhedron. When this algorithm was tested on computer generated surfaces of a known volume, the difference was less than 1·6%. Serial sections of two phantoms of a known volume were also reconstructed and a comparison of the mathematically derived volumes and the computed volume estimations gave a per cent difference of between 2·8% and 4·1%. Finally cell volumes derived using conventional methods and volumes calculated using the algorithm were compared. The mean atrial muscle cell volume derived using conventional methods was 7752·7 ± 644·7 μm3, while the mean computerized algorithm estimated atrial muscle cell volume was 7110·6 ± 625·5 μm3. For AV bundle cells the mean cell volume obtained by conventional methods was 484·4 ± 88·8 μm3 and the volume derived from the computer algorithm was 506·0 ± 78·5 μm3. The differences between the volumes calculated using conventional methods and the algorithm were not significantly different.
Sectioning and imaging hard mineral fibres in biological tissues
Authors: Johnson N. F. , Ibe K. 
Published: August 2011

SUMMARYA technique is described which overcomes the problems associated with sectioning biological tissue containing hard mineral fibres. 0·2–0·5 μm thick sections were cut with a diamond knife, placed in a folding grid, conventionally stained with uranyl acetate and lead citrate and viewed at an accelerating voltage of 200 kV in the scanning transmission mode.
Stereological estimation of the radial distribution function of centres of spheres
Authors: Hanisch K.‐H. , Stoyan D. 
Published: August 2011

SUMMARYThe usual stereological formulae yield mean values or one‐dimensional distributions. However, for the description of correlations in particle systems, second‐order characteristics are useful, for example the radial distribution function or the second‐order product density of the point process of particle centres. For the case of spherical particles some exact and approximate stereological formulae are given. These connect the spatial second‐order quantities with quantities available from planar or linear intersections.
Focused apparent image position with convergent, parallel binocular and monocular microscopes
Authors: Richards Oscar W. , Mathews Steven M. , Shaffer Steven M. 
Published: August 2011

SUMMARYThe distance from the observer's eye at which the image appears to be focused was measured with monocular, convergent and parallel eyepiece bodies, interchangeable on a Spencer microscope, with a camera lucida prism and a calibrated optometer. Five optometric tests for binocular vision and one for stereopsis made on thirty‐four observers revealed no significant correlation with the positions of the images. The apparent image position from the eye using the parallel binocular eyepieces averaged 671 mm, with the convergent eyepiece body at 587 mm, and 469 mm with monocular observation. The relations of these image positions with possible rest equilibrium positions of the accommodative mechanism of the eye and optical design of binocular instruments are discussed.
The use of polystyrene microcarriers to prepare cell monolayers for transmission electron microscopy
Authors: Sargent G. F. , Sims T. A. , McNeish A. S. 
Published: August 2011

SUMMARYA simple method is described, using polystyrene microcarrier beads, that allows cell monolayers to be prepared without distortion for transmission electron microscopy.Cells cultured on polystyrene beads (Biosilon R, Nunc, Kamstrup, Denmark) are held in an agar matrix. Before embedding, the beads are dissolved in 1, 2‐epoxypropane.The technique increases the number of observable cells, when compared to preparations of planar monolayers, and there is good preservation of morphological detail.
A technique for obtaining ribbons of epoxy and other plastic sections for light microscope histology
Authors: Richards Peter R. 
Published: August 2011

SUMMARYA method is described by which ribbons of thick, large area sections of material embedded in epoxy resins prepared from standard recipes for electron microscopy, can be cut using conventional microtomes. The epoxy blocks are double embedded in an epoxy/polyethylene glycol mixture and ribbons are cut dry with fluorocarbon coated long‐edged (‘Ralph’) glass knives. The method can also be applied to other plastic embedding media such as glycol methacrylate.
Strong evidence against section thawing whilst cutting on the cryo‐ultratome
Authors: Frederik P. M. , Busing W. M. 
Published: August 2011

SUMMARYThe distribution of ice crystal sizes in frozen thin sections correlates with the size distribution in freeze fracture replicas. In the hypothetical case of melting (and refreezing) during cyro‐sectioning this correlation should be lost as was found after intentional melting or frozen thin sections. These observations demonstrate that there is neither a through section melting nor a growth of ice crystals during cryo‐ultramicrotomy.
Photographic defocusing: a means to render recognizable line traced models of negatively stained biological specimens
Authors: Rodrigues F. Carvalho , Nunes J. F. Moura , Chagas J. Pinto , Soares J. O. 
Published: August 2011

SUMMARYA simple method of obtaining analogue images from traced models of biological specimens is presented. It consists of the photographic defocusing of traced models and it is illustrated with negatively stained cylindrical forms of the ASFV; the black lines of the trace in the model correspond to the negative stain surrounding the viral morphological subunits as seen in the electron micrograph. The photographic defocusing is the means by which the traced model is filtered and is used to introduce grey levels on an otherwise black and white image. The right amount of defocusing is attained when the width of the trace of the model equals the width of the rim of the negative stain appearing between the morphological subunits in the electron micrograph.
Polychromatic Giemsa staining for Epon semi‐thin sections
Authors: Cañete M. , Stockert J. C. 
Published: August 2011

SUMMARYA polychromatic staining procedure which uses the Giemsa stain and differentiates between several cell and tissue structures with distinct colours has been developed for semi‐thin sections of glutaraldehyde‐fixed, Epon‐embedded animal and plant tissues.The method does not require removal of the plastic and can be applied in a simple and rapid way for routine staining of semi‐thin sections with good results.
X‐ray microanalysis with Si(Li) detectors
Authors: Statham P. J. 
Published: August 2011

SUMMARYThe Si(Li) detector, with its relatively high collection solid angle, has brought X‐ray microanalysis within the operating current limits of both SEMs and transmission microscopes. At present, the main deficiencies arise in the low‐energy region of the spectrum, below about 2 keV. Here, detection efficiency falls off because of absorption in the entrance window, peaks invariably overlap and pile‐up rejection is less effective. High‐energy photons generated in transmission microscopes are responsible for new spectral artefacts and problems of overload. While computer processing of spectra can correct for most artefacts, background and peak overlaps, accuracy is fundamentally limited by counting statistics and the overall stability of the spectrometer. The technique will therefore benefit from improved design of both electronic circuitry and components. For example, advances in FET design may bring a substantial reduction in electronic noise which will not only improve resolution at low energies, but will also improve discrimination between small pulses and noise so that pile‐up rejection can be more effective. This will be most important when a very thin entrance window is used to permit observation down to the C Kα energy (282 eV) although the hazards involved in such ‘windowless' operation still limit its application. The stability of detection efficiency with time has been exploited in methods which attempt to remove the need for repetitive standardization of the spectrometer and new techniques have been developed for the analysis of thin films, particles and rough surfaces which make use of information contained in the bremsstrahlung continuum.
An X‐ray microanalytical examination of precipitation methods for the ultrastructural localization of potassium in plant tissue: II. Tetraphenyl boron
Authors: van Steveninck Margaret E. , van Steveninck R. F. M. 
Published: August 2011

SUMMARYThe possibility of using sodium tetraphenyl boron (TPB) as a precipitant for the ultrastructural localization of K+ was examined using both in vitro and in vivo studies. Because TPB salts are soluble in the usual dehydrating agents, glutaraldehyde‐urea was used for embedding. When Na TPB was introduced to the tissue together with OsO4, good cytoplasmic preservation was achieved, and deposits containing K were located within the cytoplasm and vacuoles. However, these deposits cannot be distinguished visually, so that X‐ray microanalysis is necessary to confirm the presence of K.
The development of squamous cell metaplasia in human bronchial epithelium by light microscopic morphometry
Authors: Bertram J. F. , Rogers A. W. 
Published: August 2011

SUMMARYBronchial biopsies from ten subjects, including five smokers, have been examined using light microscopic morphometry. The biopsies were free from identifiable disease. Using manual point counting and a Quantimet 720 image analysing computer, a number of parameters were measured. Computer‐based cluster analysis of seven of these parameters associated the subjects into three groups: visual inspection of the sections achieved the same separation. Four subjects (non‐smokers) had normal epithelia: four subjects (one non‐smoker, three smokers) showed mucous cell hyperplasia: two subjects (smokers) had squamous cell metaplasia. Three parameters in conjunction contained sufficient information to characterize accurately the histological appearance of the epithelia: the epithelial thickness, the volume density of intracellular mucus and the number of nuclear profiles per unit area of sectioned epithelium. Reduction of these three parameters to a linear plot closely approximated a similar reduction of the original seven parameters. These three parameters can be measured rapidly, either manually or by the Quantimet. The linear representation of these parameters provides a reproducible and objective basis for comparing specimens of bronchial epithelium.
Glycol methacrylate in light microscopy: nucleic acid cytochemistry
Authors: Cole Madison B. , Ellinger Joan 
Published: August 2011

SUMMARYTechniques utilizing Feulgen, azure B bromide, methyl green‐pyronin, gallocyanin chromalum and cresyl violet stains have been modified and adapted for visualizing nucleic acids in 0.5–2.0 μm sections of tissues embedded in glycol methacrylate (GMA). Methods for evaluating the stain specificity for DNA and RNA using deoxyribonuclease and ribonuclease digestions, aldehyde blocking, and acid extractions are also described. The specificity of the stains in GMA embedded tissues is comparable to that reported for paraffin‐embedded tissues.
Scanning X‐ray microradiography of a section of a carious lesion in dental enamel
Authors: Elliott J. C. , Dowker S. E. P. , Knight R. D. 
Published: August 2011

SUMMARYA scanning X‐ray microradiographic system is described with which it is possible to measure the X‐ray absorption in a 1 mm × 1 mm area of a section in about 27 h at a resolution of 20 μm with a reproducibility of about ± 1.5%. This system has advantages over photographic methods for certain quantitative investigations. The results can be presented in various forms including contour maps and half‐tone pictures and this is illustrated with a radiograph of a section of a carious lesion in dental enamel.
Multinucleate giant enterocytes in small intestinal villi after irradiation
Authors: Carr K. E. , Hamlet R. , Nias A. H. W. , Watt C. 
Published: August 2011

SUMMARYScanning electron microscopy of the small intestine of the mouse 5 days after X‐ or neutron irradiation has revealed the formation of giant cells on the villus surface.Correlative light microscopy and transmission electron microscopy have shown that these giant cells are syncytial in nature.Characteristic features of lipid inclusions and apical microvilli suggest that these syncytia are giant enterocytes. It has also been shown that these giant cells are in contact with the connective tissue core of the villus and have a close contact with the normal enterocytes, thus maintaining mucosal integrity. It is postulated that radiation damage has caused incomplete separation during mitosis and that attempted division occurs outside the crypts of Lieberkuhn.
The contribution of scanning electron microscopy in haematology: its role in defining leucocyte and erythrocyte disorders
Authors: Polliack Aaron 
Published: August 2011

SUMMARYThis report reviews the contribution of scanning electron microscopy (SEM) in haematology. Important observations regarding red cell shape and deformities are referred to and contributions in the definition and classification erythrocyte disorders are stressed. In this field there is no doubt that SEM has contributed much to the three‐dimensional visualization of RBC disorders.As far as leucocyte pathology is concerned the situation is less clear. SEM has contributed much to current knowledge and understanding of the surface properties of white blood cells. Normal leucocytes have different surface features and can be distinguished under the SEM. However, some overlap does occur, making individual distinction on the basis of surface architecture alone extremely difficult. The difficulties in this regard are discussed in this review and factors influencing the variability of surface microprojections are reviewed briefly.Leukaemic cells of different origins may also be distinguished under the SEM. However, while ‘hairy’ cells have typical surface features and non‐lymphoid leukaemic cells, in particular monocytes, are readily distinguished from lymphoid leukaemic cells, there is much overlap of surface topography. Undifferentiated cells and early myeloblasts and lymphoblasts have similar surface features and cannot be distinguished under the SEM. While SEM adds a valuable third dimension to morphology and ultrastructure, it cannot be used alone in the definition of difficult cases of acute leukaemia.