bluuebunny/crossref_metadata_2025 huggingface dataset:
A computer‐assisted stereological quantification program: Openstereo
Authors: Abrams Don‐Carlos , Facer Paul , Bishop Anne E. , Polak Julia M.
Published: February 2005

At present, the stereological assessment of histological sections is made possible by the use of manual counting techniques which estimate measurement parameters. These methods are tedious, time‐consuming, and subject to operator error. This paper describes a UNIX‐based computer program, OpenStereo, which was developed to facilitate the quantitative investigation of innervation and vascularity from histological sections. We designed OpenStereo to reduce operator error and increase the efficiency of stereological point counting for volume estimation and intercept counting for surface area analysis. The program was written in the C language for the SunTM Workstation and uses the XView graphics user interface. Digital images, obtained by a variety of modalities, may be processed using stereological point counting, interceptions, planimetry, or thresholding techniques. The program displays selected images in a random fashion for analysis or processing and records the number of manually selected points or interceptions. Delineation of the reference space provides the computer with the data necessary to calculate volume or surface densities. The efficiency of OpenStereo was demonstrated by performing a pilot study on the quantification of innervation in the normal human colon and ileum. This stereological package benefits from the features of the X‐windowing environment and has proved to be suitable for what has hitherto been a tedious and time‐consuming task. © 1994 Wiley‐Liss, Inc.
Three‐dimensional reconstructions of autonomic projections to the gastrointestinal tract
Authors: Powley Terry L. , Holst Mary‐Clare , Boyd David B. , Kelly Joshua B.
Published: February 2005

Three‐dimensional reconstruction protocols in confocal microscopy are typically considered in terms of rendering separate stacks of optical sections. Single stacks, however, include volumes that are often too small to permit descriptions of entire neurons, complete axonal arbors, or complex neural networks. Furthermore, traditional tissue preparation protocols generally yield specimens too limited to permit reconstructions of complex neural systems. For 3‐D analyses of extensive networks such as the autonomic nervous system projections within the viscera, it is critical to incorporate appropriate tissue techniques, including suitable tracer protocols, into the reconstruction strategy. This report summarizes complementary technologies, including whole mount procedures, tracer techniques for identifying single fibers in situ, and methods of examining stacks of optical images, which make it practical to describe the complete terminal field of an individual axon in the gastrointestinal tract. Such methods establish that vagal motor axons travel long distances within their target organs, collateralize frequently, and ramify extensively. Vagal afferents have extensive, complex, and, in some cases, polytopic arbors within target tissues. © 1994 Wiley‐Liss, Inc.
Phorbol ester‐stimulated stellation in primary cultures of astrocytes from different brain regions
Authors: Davis‐Cox Margaret I. , Turner James N. , Szarowski Donald , Shain William
Published: February 2005

Stellation is the process by which astrocytes change from epithelial‐like to process‐bearing cells. Stellation occurs following activation of either cyclic AMP‐dependent protein kinase or protein kinase C. This process occurs through tubulin‐dependent rearrangement of the cytoskeleton. We have evaluated the ability of phorbol, 12‐myristate, 13‐acetate (PMA) to induce astrocyte stellation. Astrocytes from five brain regions (cerebellum, cerebral cortex, hippocampus, diencephalon, and brain‐stem) were examined to determine if all astrocytes would exhibit similar responses to this activator of protein kinase C. Stellation was evaluated following cell fixation by either phase optics using conventional light microscop, or scanning laser confocal light microscopy of cultures prepared using immunocytochemistry for tubulin and glial fibrillary acidic protein. Both the number of cells responding to PMA and the sensitivity to PMA varied for astrocytes from each brain region. PMA‐induced stellation was most robust in cerebellar and brainstem astrocytes, with greater than 70% responding. Less than 40% of hippocampal and diencephalic astrocytes responded to PMA at the maximum does (10−5 M). PMA also induced different numbers of processes or branching patterns of processes on astrocytes from different brain regions. The protein kinase C induced stellation response in astrocytes supports the hypothesis that astrocytes contribute to neural plasticity. © 1994 Wiley‐Liss, Inc.
Construction and analysis of a database representing a neural map
Authors: Troyer Todd W. , Levin Jacob E. , Jacobs Gwen A.
Published: February 2005

We describe the development and analysis of a quantitative database representing the global structural and functional organization of an entire sensory map. The database was derived from measurements of anatomical characteristics of a statistical sample of typical mechanosensory afferents in the cricket cercal sensory system. Anatomical characteristics of the neurons were measured quantitatively in three dimensions using a computer reconstruction system. The reconstructions of all neurons were aligned and scaled to a common standard set of dimensions, according to a highly reproducible set of intrinsic fiducial marks. The database therefore preserves accurate information about spatial relationships between the neurons within the ensemble.

Algorithms were implemented to allow the integration of electrophysiological data about the stimulus/response characteristics of the reconstructed neurons into the database. The algorithms essentially map a physiological function onto a “field” representing the continuous distribution of synaptic terminals throughout the neural structure. Subsequent analysis allowed quantitative predictions of several important functional characteristics of the sensory map that emerge from its global organization. First, quantitative and testable predictions were made about ensemble response patterns within the map. The predicted patterns are presented as graphical images, similar to images that might be observed with activity‐dependent dyes in the real neural system. Second, the synaptic innervation patterns from the sensory afferent map onto the dendrites of a postsynaptic target interneuron were predicted by calculating the overlap between the interneuron's dendrites with the afferent map. By doing so, several aspects of the stimulus/response properties of the interneuron were accurately predicted. © 1994 Wiley‐Liss, Inc.
Morphological characteristics of boar efferent ductules and epididymal duct
Authors: Stoffel Michael H. , Friess Armin E.
Published: February 2005

The aim of the present study was to provide a comprehensive morphological analysis of the porcine epididymis in view of the specific functions being performed in different regions of this organ. Blood supply and microvasculature of efferent ductules and epididymal duct were investigated by means of corrosion casts which were analysed macroscopically and by scanning electron microscopy. This revealed blood supply to the testis and epididymis to be closely related. The capillary pattern was typical for the efferent ductules, the caput, corpus, and distal cauda epididymidis, respectively. Corrosion casts were also used to visualize the course of the efferent ductules themselves. Tissue samples from different regions of the efferent ductules and epididymal duct were examined by light microscopy and both scanning and transmission electron microscopy, with special attention being payed to transitional areas. Morphological criteria allowed the distinction of three segments within the efferent ductules and of the initial segment, proximal caput, distal caput, corpus, proximal cauda, and distal cauda regions of the epididymal duct. Components of the endocytic apparatus of efferent ductule principal cells were identified by ferritin uptake. Ultrastructural evidence of absorption in the epididymal duct was particularly prominent in proximal and distal caput. Extensive cisternae of rough endoplasmic reticulum and a well‐developed Golgi apparatus were indicative of active protein synthesis and secretion especially in the distal caput and corpus regions. However, assignment of various organelles in principal cells of the epididymal duct to either absorptive or secretory pathways still remains tentative. © 1994 Wiley‐Liss, Inc.
Order‐disorder in T, T′, and T* phase: Superconductors and related materials
Authors: González‐Calbet J. M. , Sayagués M. J. , Varela A. , Alonso J. M. , Caneiro A. , Vallet‐Regí M.
Published: February 2005

After reviewing microstructural studies on superconducting materials showing T, T′, and T* structural types, results are presented on the microstructure of some n‐type superconductors and related materials prepared with accurate control of the oxygen stoichiometry. Electron microscopy is used to describe the ordering of interstitial oxygen defects in T‐type La2NiO4+δ leading to the formation of the n = 2 term of a homologous series with the general formula La8nNi4nO16n+1. Structural transitions and superstructure formation in the Pr2−x−yCexSryCuO4‐δ system are reported, where T, T′;, and T* phases are isolated as a function of both Ce and Sr content. © 1995 Wiley‐Liss, Inc.
Transmission EELS of oxide superconductors with a cold field emission TEM
Authors: Wang Y. Y. , Zhang H. , Dravid V. P.
Published: February 2005

Electron energy loss spectrometry (EELS) with a cold field emission gun (cFEG) transmission electron microscope (TEM) is implemented to analyze the evolution of the electronic structure and dielectric function of oxide superconductors. The O‐K core loss spectra of p‐type doped oxide superconductors are analyzed in terms of holes formation on oxygen sites, while low loss spectra are analyzed for free carrier plasmas, other spectral excitations, and their crystallographic confinement.

It is illustrated that the transmission EELS with a cFEG TEM very much complement soft X‐ray absorption spectroscopy and optical spectroscopy, with the added advantages of high spatial resolution (∼1–100 nm), and is compatible with other analytical, diffraction, and imaging techniques, which are readily available in a cFEG TEM. © 1995 Wiley‐Liss, Inc.
Mesenchymal‐epithelial interactions and transforming growth factor‐β1 expression during normal and abnormal prostatic growth
Authors: Timme Terry L. , Truong Luan D. , Slawin Kevin M. , Kadmon Dov , Park Sang Hee , Thompson Timothy C.
Published: February 2005

Mesenchymal‐epithelial interactions are associated with growth and morphogenesis of the prostate. We have detected three isoforms of transforming growth factor β (TGF‐β) in the developing mouse prostate that may mediate some of these interactions. Separation of the fetal urogenital sinus (UGS) tissue into mesenchymal and epithelial components indicated that mRNA expression of TGF‐β;1, 2, and 3 was more abundant in the mesenchyme compared to the epithelium. Immunohistochemical analysis revealed accumulation of TGF‐β1 in the mesenchyme surrounding ductules in the UGS and neonatal prostate. Further analysis of TGF‐β1 localization in surgically removed adult human prostate tissues revealed more intense staining associated with regions of abnormal growth compared to normally appearing tissue. The percent of the total stained area with extracellular accumulation of TGF‐β1 was 59% in prostate cancer, 26% in benign prostatic hyperplasia (BPH), and 8.6% in normal tissue. In additional immunohistochemical studies we observed that intracellular TGF‐β1 was predominantly associated with the epithelial cells in prostate cancer (epithelial cells = 33.5% of the total stained area, stromal cells = 13.3%, and unstained = 53.2%), whereas in BPH intracellular TGF‐β1 was predominantly associated with stromal cells (stromal cells = 32.2% of the total stained area, epithelial cells = 12.3%, and unstained = 55.5%). Although additional experimental and clinical studies are needed to better understand the relationships between TGF‐β1 and abnormal prostatic growth, our observations thus far suggest a role for TGF‐β1 in the development of benign and malignant growth abnormalities in the prostate. One approach to establishing the pathobiological significance of TGF‐β1 accumulation in the prostate is by introducing and overexpressing the TGF‐β1 cDNA in prostate tissue using the mouse prostate reconstitution model system. We discuss applicability of transgenic animal and organ reconstitution models for experimental studies concerning TGF‐β—induced prostate growth abnormalities. © 1995 Wiley‐Liss, Inc.
Patterns of myosin isoforms in mammalian skeletal muscle fibres
Authors: Hämäläinen Nina , Pette Dirk
Published: February 2005

The present article attempts to combine existing information on the distribution of fast and slow myosin isoforms in histochemically distinct muscle fibres. Four myosin heavy chain (MHC) isoforms, MHCI, MHCIIa, MHCIIb, and MHCIId(x), have been identified in small mammals and have been assigned to the histochemically defined fibre types I, IIA, IIB, and IID(x), respectively. These fibres express only one MHC isoform and are called pure fibre types. Hybrid fibres expressing two MHC isoforms are regarded as transitory between respective pure fibre types. The existence of pure and hybrid fibres even in normal muscles under steady state conditions creates a spectrum of fibre types. The multiplicity of fibre types is even greater when myosin light chains are taken into account. A large number of isomyosins results from the combinatorial patterns of various myosin light and heavy chains isoforms, further increasing the diversity of muscle fibres. As shown by comparative studies, the distribution of different fibre types varies in a muscle‐specific, as well as a species‐specific manner. © 1995 Wiley‐Liss, Inc.
Computer graphics of SEM images facilitate recognition of chromosome position in isolated human metaphase plates
Authors: Hodge L. D. , Barrett J. M. , Welter D. A.
Published: February 2005

There is general agreement that at the time of mitosis chromosomes occupy precise positions and that these positions likely affect subsequent nuclear function in interphase. However, before such ideas can be investigated in human cells, it is necessary to determine first the precise position of each chromosome with regard to its neighbors. It has occurred to us that stereo images, produced by scanning electron microscopy, of isolated metaphase plates could form the basis whereby these positions could be ascertained. In this paper we describe a computer graphic technique that permits us to keep track of individual chromosomes in a metaphase plate and to compare chromosome positions in different metaphas plates. Moreover, the computer graphics provide permanent, easily manipulated, rapid recall of stored chromosome profiles. These advantages are demonstrated by a comparison of the relative position of group A—specific and groups D—and G—specific chromosomes to the full complement of chromosomes in metaphase plates isolated from a nearly triploid human‐derived cell (HeLa S3) to a hypo‐diploid human fetal lung cell. © 1995 Wiley‐Liss, Inc.
Ultrastructural characterization of neurons recorded intracellularly in vivo and injected with lucifer yellow: Advantages of immunogold‐silver vs. immunoperoxidase labeling
Authors: Branchereau Pascal , Van Bockstaele Elisabeth J. , Chan June , Pickel Virginia M.
Published: February 2005

Immunoperoxidase labeling of lucifer yellow provides a sensitive method for morphological characterization of neurons recorded intracellularly in vitro or in vivo. However, the reaction product is often so dense that it obscures ultrastructural details necessary for the analysis of synaptic contacts onto individually filled neurons. In the present study, we describe a silver intensification procedure using 1 nm gold labeling of lucifer yellow as an optimal means for immunocytochemically identifying single physiologically characterized neurons at the ultrastructural level. Single neurons in the frontal cortex of anesthetized rats were impaled in vivo and filled with lucifer yellow. The brians were then perfused with an acrolein fixative. Single vibratome sections through the recording site were reacted with a rabbit antibody directed against lucifer yellow followed by goat anti‐rabbit 1 nm gold‐labeled IgG and silver intensified. For comparison, additional sections were processed for immunoperoxidase detection of lucifer yellow. Labeled sections were processed for light microscopy or embedded in plastic for electron microscopy. The immunogold‐silver label as well as peroxidase reaction product of lucifer yellow was readily detected in cell bodies, proximal and distal dendrites, and spines. However, in contrast to immunoperoxidase, the immunogold‐silver reaction did not obscure subcellular orgnelles. Most importantly, the synaptic junctions formed by afferents to the filled neuron were more easily identifiable following the immunogold‐silver procedure. This clear visualization of postsynaptic densities is essential for examining synaptic circuitry between afferents and physiologically characterized neurons. © 1995 Wiley‐Liss, Inc.
Dystrophin expression in the developing conduction system of the human heart
Authors: Ginjaar Ieke B. , Virágh Szabolcs , Markman Marry W. M. , Van Ommen Gert‐Jan B. , Moorman Antoon F. M.
Published: February 2005

Duchenne muscular dystrophy (DMD) is frequently associated with myocardial involvement. Dystrophin, the DMD protein, is found at the plasmamembrane of striated muscle fibers. Although dystrophin is missing in most or all muscle fibers of DMD patients, cardiac muscle is not as severely affected as skeletal muscle. Therefore it is of great importance to study the expression of dystrophin in normal cardiac muscle. We performed immunohistochemical studies and examined cardiac muscle of fetuses of 8 to 13 weeks of development on dystrophin expression. At these stages dystrophin is observed in the myocytes of the developing ventricular conduction system and in the atrial cardiomyocytes. Dystrophin was absent from the heart of a 12‐week‐old DMD fetus. © 1995 Wiley‐Liss, Inc.
Mapping of the orientation of myocardial cells by means of polarized light and confocal scanning laser microscopy
Authors: Jouk Pierre‐Simon , Usson Yves , Michalowicz Gabrielle , Parazza Franck
Published: February 2005

The study of the topological organisation of myocardial cells is a basic requirement for the understanding of the mechanical design of the normal and pathological heart. We developed a technique based on multiparametric image analysis of transmitted polarized light to generate maps of the azimuth and the elevation angles of the myocardial cells. The properties of birefringence of the myocardium embedded in methylmetacrylate were measured in papillary muscles with monitored 3D orientation. This birefringence is positive uniaxial with a 0° extinction angle when the axis of the fiber is parallel to the axis of the polarizer or the analyzer. Thick sections were studied between crossed polars, and four images of each section were digitized for an angle of the polarizer with the section varying from 0–67.5° in steps of 22.5°. The amounts of transmitted light for each setup of the polarizer were combined in order to extract the values of the azimuth angle (modulo 90°) and the elevation angle of the myocardial cells, according to the Johannsen equation. The respective maps of these angles were calculated and then assessed with confocal scanning laser microscopy. This method provides an efficient and accurate tool for the study of the histological architecture of the fetal and neonatal heart. © 1995 Wiley‐Liss, Inc.
Section directed cryosectioning of specimens for scanning electron microscopy: A new method to study cardiac development
Authors: Seo Jeong‐Wook , Kim Eul‐Kyeong , Brown Nigel A. , Wessels Andy
Published: February 2005

A new method to study the developing heart was developed. Using this “section directed” cryosectioning method, appropriate fixed embryos can be trimmed optimally to obtain sectional planes that, if necessary, can be matched with histologically treated sections. As a result, the morphological information obtained with the scanning electron microscope can be compared in detail with the information on the molecular phenotypes of the subpopulations of cells as deducted from staining patterns of the sections. This method allows combination of the specific advantages of sophisticated histological techniques, such as immunohistochemistry and in situ hybridisation, with those of the scanning electron microscope. © 1995 Wiley‐Liss, Inc.
Design and implementation of a database and program for 3D reconstruction from serial sections: A data‐driven approach
Authors: Verbeek Fons J. , Huijsmans D. P. , Baeten R. J. A. M. , Schoutsen N. J. C. , Lamers W. H.
Published: February 2005

This paper describes a structured approach for a standard setup of a computer program for 3D reconstruction from serial sections. Three‐dimensional reconstruction as a technique increases in importance as, along with modern immunohistochemical techniques, it is a tool in the understanding of three‐dimensional development patterns. In order to apply 3D reconstruction technique in a standard laboratory setup, an attempt was made to streamline the input and the manipulation of the data such that results are obtained easily. One will find a combination of two approaches in this paper: the first is a strict ordering of the complex data, and the second is an ordering of the processes that one wishes to apply on the data (together, these two approaches constitute an information analysis); because it was observed that developmental biologists tend to work from simple lines to describe their observations, the contour model was chosen as the vehicle to build a reconstruction model from. Consequently, the data is ordered in a database that has to be manipulated to get the data out in the desired format. The most important output format is a display of the reconstructed contour stack on a graphical computer screen. Together with the other data manipulation processes, such as the input, the inspection, the revision (correction), and the reconstruction, all processes are described using the reconstruction of an 11 embryonic days (ED) rat embryo as an example. Finally, the merits of the program are illustrated with an example from the development of the human embryonic heart. © 1995 Wiley‐Liss, Inc.
Three‐dimensional analysis and visualization of myofibrillogenesis in adult cardiomyocytes by confocal microscopy
Authors: Messerli J. M. , Perriard J.‐C.
Published: February 2005

Confocal light microscopy has found its place among the standard analytical tools in cell and molecular biology. When combined with techniques such as immunofluorescence or fluorescent in situ hybridization, the spatial distribution of individual biological components can be traced within cells and tissues and, under certain circumstances, even with living samples. In this article, advanced 3D visualization techniques have been applied to analyze the distribution of myofibrillar proteins in cultured adult rat cardiomyocytes. By combining confocal immunofluorescence microscopy with specially designed three‐dimensional visualization, we have obtained images which are similar to those obtained with the scanning electron microscope. The subcellular distribution of proteins expressed after transfection of cDNA is monitored in the cultured heart cells. The expressed proteins are distinguished from their endogenous counterparts by the use of an epitope tagging technique. The described methods are suitable to specifically monitor the behavior of several closely related isoprotein mutants in cell or tissue preparations. © 1995 Wiley‐Liss, Inc.
Immunocytochemistry of plant defense mechanisms induced upon microbial attack
Authors: Benhamou Nicole
Published: February 2005

During the past few years, cyto‐ and immunocytochemical techniques have been developed and widely used for locating and identifying various molecules in plant cell compartments. The last decade has witnessed tremendous improvements in molecular cytology, thus allowing an accurate in situ detection of various components thought to play important biological functions in the plant metabolism. The use of immunocytochemistry to investigate resistance mechanisms of plants upon pathogen attack has provided key information on the defense strategy that plants elaborate during a host‐pathogen interaction. Of the various proteins induced in response to infection, chitinases and β‐1,3‐glucanases have been the focus of particular attention due to their believed antimicrobial activity through the hydrolysis of the main fungal wall components, chitin and β‐1,3‐glucans. Attention has also been paid to β‐fructosidase, the enzyme that hydrolyzes sucrose into glucose and fructoside. The marked accumulation of this enzyme upon pathogen infection has led to the consideration that infection may greatly infleunce the metabolic activity of colonized tissues by creating alterations of source‐sink relationships. Another facet of the plant's defense strategy that has been the focus of considerable interest is related to the accumulation of structural compounds, such as hydroxyproline‐rich glycoproteins and callose, to reinforce the wall architecture, thus decreasing vulnerability to microbial enzymes. A number of alternatives designed to improve plant protection towards pathogen invasion have been suggested. Among these, the production of transgenic plants expressing constitutively a foreign resistance gene and the pretreatment of plants with elicitors of defense reactions have been the subject of intensive studies at the molecular, biochemical, and cytological levels. Results of such studies clearly demonstrate the important contribution that cyto‐ and immunocytochemical approaches can make to our knowledge of how plants defend themselves and how plant disease resistance can be directly enhanced. These approaches will undoubtedly be active areas for future research in the development of biological control alternatives in which the mode of action of the product used is of key importance. © 1995 Wiley‐Liss, Inc.
Immunogold localization of actin in the testis and exocrine pancreas: Spatial relationship with tight junctional strands
Authors: Kan Frederick W. K. , Lin Yan
Published: February 2005

The fracture‐label technique was used in conjunction with a monoclonal antibody to actin and the phospholipase A2‐colloidal gold (PLA2‐CG) method to examine the spatial distribution of actin filaments in relation to the three‐dimensional arrangement of tight junctional strands in rat testes and exocrine pancreatic acinar cells. The intimate association of actin filaments with tight junctional strands in the pancreas and testis was also illustrated by a doublelabeling experiment in which freeze‐fractured pancreas or testis was labeled with monoclonal antibody‐protein A‐gold (30 nm gold size) followed by incubation with a PLA2‐CG complex (11 nm gold size). Freeze‐fracture‐exposed tight junctional strands in both testicular and exocrine pancreatic cells labeled by PLA2‐CG complex indicated the presence of phospholipids in these cylindrical membranous structures. Immunolabeling of freeze‐fractured testes with a monoclonal antibody to actin revealed a narrow band of gold particles juxtaposed to the cytoplasmic aspect of the protoplasmic membrane halves decorated with parallel linear arrays of cylindrical tight junctional strands. Many of the gold particles representing actin antigenic sites were in direct contact with the cross‐fractured tight junctional strands. Fracture‐label preparations of exocrine pancreas labeled with the monoclonal anti‐actin antibody also exhibited a similar labeling pattern at the apex of acinars cells where the tight junction complex is located. Double‐labeling experiments revealed the simultaneous labeling of actin and phospholipids in the same fracture‐label preparations. Digestion of testicular and pancreatic tissue samples in a free PLA2 solution prior to labeling with the monoclonal antibody or PLA2‐CG complex removed not only the gold labeling previously seen over the tight junctional strands but also reduced drastically the immunolabeling for actin that was previously seen associated with the tight junction complex. Taken together, results of the present study showed that actin filaments are structural components of the tight junction strands and are connected to the cytoplasmic aspect of the latter structures. The interaction between this particular cytoskeletal element and the tight junction may be through the binding of a special domain of the actin filament to the phospholipids that partially make up the tight junctional complex. © 1995 Wiley‐Liss, Inc.
Morphological studies of the developing human esophageal epithelium
Authors: Ménard Daniel
Published: February 2005

This article focusses on the structural development of human esophageal ciliated epithelium. A combination of transmission electron microscopic (TEM), scanning electron micro‐scopic (SEM), radioautographic, and light microscopic (LM) analyses were carried out using intact fetal tissues between 8 and 20 weeks of gestation as well as cultured esophageal explants. Up to the age of 10 weeks, the stratified esophageal epithelium consisted of two longitudinal primary folds. The surface cells were undifferentiated and contained large glycogen aggregates. Between 11 and 16 weeks, the primary folds (now up to four) had developed secondary folds. The thickness of the epithelium drastically increased (123%) in concomittance with a differentiation of surface columnar ciliated cells. These highly specialized surface cells exhibited junctional complexes and well‐developed organelles with numerous microvilli interspesed among the cilia. Transverse sections revealed the internal structure of the cilia with a consistent pattern of nine doublet microtubules surrounding a central pair of single microtubules. Freeze‐fracture studies illustrated the presence of a ciliary necklace composed of 6 ring‐like rows of intramembranous particles. They also revealed the structure of ciliary cell tight junctions consisting of up to nine anastomosing strands (P‐face) or complementary grooves (E‐face). Ultrastructural studies (LM, TEM, SEM) of the esophageal squamous epithelium obtained after 15 days of culture showed that the newly formed epithelium was similar to adult human epithelium. Finally LM and SEM observations established that the esophagogastric junction was not yet well delineated, consisting of a transitional area composed of a mixture of esophageal ciliated cells and gastric columnar mucous cells. © 1995 Wiley‐Liss, Inc.
Freeze‐fracture and immunohistochemical studies of gap junctions in human gastric mucosa with special reference to their relationship to gastric ulcer and gastric carcinoma
Authors: Ohkusa T. , Fujiki K. , Tamura Y. , Yamamoto M. , Kyoi T.
Published: February 2005

Our aim was to determine whether the development of gap junctions in the human gastric mucosa has any relation to gastric ulcer and gastric carcinoma. Freeze‐fracture replicas were prepared from the endoscopic biopsy specimens of 20 patients with gastric ulcer and 7 healthy volunteers. Large fractured areas of lateral cell membranes of surface mucous cells were examined randomly under an electron microscope. Small gap junctions were observed between gastric surface mucous cells in all healthy volunteers. Gap junctions in the patients with gastric ulcer were significantly fewer than in the healthy volunteers. In addition, gap junctions in patients with recurrent ulcer were significantly fewer than in those with first‐onset ulcer. There was no obvious relationship between age and the development of gap junctions in patients with gastric ulcer or in healthy volunteers. In the areas of intestinal metaplasia, gap junctions were occasionally seen between absorptive cells of the villi, but not in the lateral membranes of goblet cells. Fresh frozen sections for indirect immunofluorescence were prepared from the endoscopic biopsy specimens of 19 patients with gastric ulcer and 5 patients with gastric cancer. Monoclonal antibody against liver gap junction protein (anti‐connexin 32, 6–3G11) was used for the indirect immunofluorescence. On the border of gastric ulcer, fluorescent spots in the surface mucous cells were significantly fewer than in the surface mucous cells of the body and antrum which were distant from the ulcer area in the same patients. In gastric cancer tissue specimens, fluorescent spots were not observed at all. On the other hand, fluorescent spots in the noncancerous tissue of the patients with gastric cancer were present along the intercellular junctions between gastric surface mucous cells. These findings suggest that loss of intercellular communication via gap junctions is associated with gastric ulcer formation and gastric cancer formation. © 1995 Wiley‐Liss, Inc.
Ultramicrotomy of nanocrystalline materials
Authors: McMahon G. , Malis T.
Published: February 2005

The methodology and one of the first attempts to produce transmission electron microscopic (TEM) specimens of nanocrystalline metals, alloys and ceramics by ultramicrotomy are presented. Samples of the pure elements Co, Pd; alloys of Y‐12 at.% Fe, Al‐7 at.% Ag and W‐30 at.% Ga; and ZnO ceramic, were found to section successfully to varying degrees. Advantages of sections prepared through ultramicrotomy over ion beam methods include extensive electron‐transparent regions of uniform thickness and absence of ion beam damage. Typical artefacts were observed (knife marks, tearing, pull‐out, shear lamellae, section curling, and anodic dissolution) but did not impede TEM analysis significantly. A potentially important effect observed was that of a texture development upon sectioning of the Co and Pd samples. It is thought that this unusual phenomenon results from the extremely fine scale of the microstructure and the purity of the Co and Pd samples, and may be enhanced by frictional heating effects and the state of the knife edge. © 1995 Government of Canada.

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Electrochemical and microstructural study of oxide films formed electrochemically at microcrystalline al‐fe‐v‐si alloys
Authors: Thomas S. C. , Birss V. I. , Steele D. , Tessier D.
Published: February 2005

A recent advance in metallurgical technology has been the application of rapid solidification techniques to Al alloy production. FVS0812 is the designation given to a microcrystalline Al‐based alloy consisting of 8 wt% Fe, 1 wt% V and 2 wt% Si. It is a two‐phase alloy, consisting of ca. 27 vol percent of approximately spherical Fe‐V‐Si‐rich dispersoids in an essentially pure Al matrix. The high strength, low density properties of this advanced material, and other related alloys, have not yet been realized, however, due, in part, to the inability of the alloy to form a thick, adherent, abrasion‐resistant outer surface oxide film, a feature readily achieved at conventional Al alloys by normal anodizing methods. The present research has involved an electro‐chemical study of oxide film growth at the 812 alloy, with the specific goals being to seek an understanding of the origin of the oxide film growth problem and ultimately to propose alternative approaches to the formation of a thick, stable oxide film at this material. The techniques used in this research have included electrochemical methodologies such as cyclic voltammetry and electrochemical impedance spectroscopy. Crucial information has been obtained through transmission electron microscopy (TEM) of ultramicrotomed specimens. Experiments were carried out initially in neutral borate solutions to characterize the compact barrier oxide film formed in this environment and expected to be present beneath the porous oxide film formed in the normal sulfuric acid anodizing medium. In borate solutions, the electrochemical results implied oxide film thicknesses which were less than seen subsequently by TEM work, suggesting either that the barrier film at the 812 alloy can be penetrated by solution in very fine pores (not resolvable by conventional TEM) at its outer surface or that dispersoids trapped in the oxide film cause differential oxide film thicknesses to develop across the alloy surface. In sulfuric acid solutions, dissolution of Fe and V occurs from the 812 alloy during anodization. Both impedance and TEM studies reveal the absence of a barrier film at the 812 alloy surface. Also, the thick oxide overlayer has a tortuous and more open pore structure than formed at Al and the oxide film is also substantially thinner than it should be. It is suggested that the absence of a barrier oxide film indicates that the sulfuric acid anodizing medium is too aggressive for oxide film formation at the 812 alloy, resulting in excessive dissolution and poor oxide film qualities. © 1995 Wiley‐Liss, Inc.
Gap junctions in blood forming tissues
Authors: Rosendaal Martin
Published: February 2005

More than ten research groups have now reported the presence of gap junctions in blood‐forming tissue or cultured cells. It is time to accept that these cell‐coupling structures are present in this tissue. To find out what they are doing here we need to develop appropriate experimental techniques. This review covers the particular problems of investigating direct cell‐cell communication by gap or other junction in undisturbed haemopoietic tissue. It then describes and assesses the published reports of haemopoietic gap junctions. Recently, in the author's laboratory, three means of increasing the number of gap junctions 50‐ to 100‐fold in mouse marrow have been described, as well as techniques for doing so in culture. There is a complete report of this work here. At present it is quite unclear what function gap junctions serve in blood‐formation, perhaps it is some consolation that 30 years after their ultramicroscopic discovery it is also true for all other unexcitable tissues. Possibly the ability to up‐regulate their expression in haemopoietic tissue will help us find out what their role is in blood formation. © 1995 Wiley‐Liss, Inc.
Gap junctions revealed by freeze‐fracture electron microscopy
Authors: Shivers Richard R. , McVicar Lorne K.
Published: February 2005

Gap junctions provide the basis for the formation of elaborate networks of communication between cells in animal tissues. Electron microscopic examination of thin sections of plastic embedded gap junctions has provided valuable information on the anatomy and function of these remarkable structures. Freeze‐fracture electron microscopy, however, has made available unique vistas of gap junction‐bearing intramembrane surface–surface previously inaccessible to the researcher's eyes. Data on population density, distribution, size, geometry of intramembrane particle packing, and structural responses of gap junction components to experimental manipulation are simply and easily obtained with freeze fracture. Recent developments of sophisticated protocols of immunocytochemistry as applied to freeze‐fracture replicas further serve to reinforce the notion that freeze‐fracture is a powerful tool for study of gap junctions. Molecular techniques of gap junction gene transfection promise to add a truly unique dimension to investigations of the broad spectrum of functional roles of gap junctions. © 1995 Wiley‐Liss, Inc.
Electron microscopic image analysis of cardiac gap junction membrane crystals
Authors: Yeager Mark
Published: February 2005

Cardiac gap junctions play an important functional role in the myocardium by electrically coupling adjacent cells, thereby providing a low resistance pathway for cell‐to‐cell propagation of the action potential. Two‐dimensional crystallization of biochemically isolated rat ventricular gap junctions has been accomplished by an in situ method in which membrane suspensions are sequentially dialyzed against low concentrations of deoxycholate and dodecyl‐β‐D‐maltoside. Lipids are partially extracted without solubilizing the protein, and the increased protein concentration facilitates two‐dimensional crystallization in the native membrane environment. The two‐dimensional crystals have a nominal resolution of 16 Å and display plane group symmetry p6 with a = b = 85 Å and γ = 120°. Projection density maps show that the connexons in cardiac gap junctions are formed by a hexameric cluste rof α1 connexin subunits. Protease cleavage of α1 connexin from 43 to 30 kDa releases ∼13kDa from the carboxy‐tail, and the projection density maps are not significantly altered. Uranyl acetate stain penetrates the ion channel, whereas phospho‐tungstic acid is preferentially deposited over the lipid regions. This differential staining can be used to selectively probe the central channel of the connexon and the interface between the connexon and the lipid. The hexameric design of α1 connexons appears to be a recurring quaternary motif for the multigene family of gap junction proteins. © 1995 Wiley‐Liss, Inc.
Hormonal control of the biosynthesis of hamster oviductin
Authors: Malette Brigitte , Filion Benoit , St‐Jacques Sylvie , Kan Frederick W. K. , Bleau Gilles
Published: February 2005

In several mammalian species, the epithelial secretory cells of the oviduct synthesize and secrete specific glycoproteins that become associated with the zona pellucida of the ovulated oocyte. These glycoproteins are collectively designated as oviductins. A monoclonal antibody directed against hamster oviductin was used to study the ontogeny of this glycoprotein. Indirect immunofluorescence experiments performed on sections of hamster oviduct revealed that the glycoprotein begins to be secreted in 10‐day‐old females and that all of the oviductal secretory cells showed fluorescent staining by day 14. The intensity of the immunofluorescence reaction reached a maximum in the 28‐day‐old females. The oviducts of the 7‐day‐old hamster incorporated [35S]methionine in vitro into several proteins; however, the production and secretion of detectable amounts of radiolabeled oviductin only began at 14 days of age and reached a maximum at day 28 of age. It appears that the ontogeny of oviductin parallels the hormone dependent changes leading to sexual maturation and that its maximum secretion is already established at the time of the first ovulatory cycle. These results are substantiated by the fact that the production of oviductin is induced in estradiol‐treated, but not progesterone or non‐treated prepubertal animals, as determined by indirect immunofluorescence experiments. © 1995 Wiley‐Liss, Inc.
Isolation, cell culture, and characterization of oviduct epithelial cells of the cow
Authors: Joshi Madhusudan S.
Published: February 2005

This report describes an easy method of isolation and cell culture of the epithelial cells of cow oviduct. Incubation of cow oviduct with 0.1 mg/ml collagenase in the lumen for 90 minutes helped to dislodge large numbers of ciliated and secretory epithelial cells. The isolated cells, when seeded on plastic, proliferated very quickly and became confluent in 8–10 days in 35 mm Petri dishes. The isolated ciliated cells which attached to the plastic dish lost their cilia after 4–5 days in culture. The cultured epithelial cells were keretin positive. The isolated bovine oviduct epithelial cells, when cultured on plastic precoated with 10 mg/ml matrigel, organized themselves into hollow tubes or spheres with microvilli directed towards the lumen. The epithelial cells seeded on 2 mg/ml matrigel became subconfluent in 15–20 days after seeding. The histoarchitecture of the secretory cells growing in vitro on matrigel resembled that of intact oviduct secretory epithelial cells. Occasional ciliated cells containing large number of mitochondria were observed in the monolayer cultured on 2 mg/ml matrigel substratum but possessed few cilia. The oviduct epithelial cells cultured on 2 mg/ml matrigel incorporated 35S‐methionine linearily into protein up to 8 hours in the presence of estradiol or progesterone. The fluorograph of the newly synthesized proteins indicated the presence of an additional 60 kd protein in the cell extract of epithelial cells incubated with estradiol. © 1995 Wiley‐Liss, Inc.
Morphological study of changes in the baboon oviductal epithelium during the menstrual cycle
Authors: Louise Odor D. , Augustine James R.
Published: February 2005

Oviductal epithelium of the baboon, Papio cynocephalus, was studied utilizing light, scanning, and transmission electron microscopy. Results of counts made of nonciliated, ciliated, and ciliogenic cells were analyzed statistically. The percentages of nonciliated cells of the fimbria and ampulla during the early proliferative and late secretory stages of the menstrual cycle were significantly greater than those during the mid‐proliferative and late proliferative‐early secretory stages, due to deciliation. This paper emphasizes previously unreported apical surface morphology as viewed by scanning and transmission electron microscopy. The microvillar pattern of the fimbrial secretory cells differs from that of the ampullar and isthmic cells in that the microvilli originate from thick apical protrusions and vary greatly in length and number as related to the cycle. A ridge demarcating the apical intercellular junction is composed of rows of microvilli during the early proliferative and late secretory stages. During the early proliferative and late secretory stages an increased degree of invagination of the basal and lateral plasma membranes occurs as the height and width of the cells decreases. The general numbers and distribution of the organelles of the various types of oviductal cells agree with that described for the ampulla and isthmus by Verhage et al. [(1990) Am. J. Anat., 187:81–90]; however, fimbrial epithelium was not included in that study. Other cyclic ultrastructural changes not examined previously include variation in the number of lipid droplets and their location, and in the number and relationships of glycogen particles to other structures. © 1995 Wiley‐Liss, Inc.
A human oviduct‐specific glycoprotein: Synthesis, secretion, and localization during the menstrual cycle
Authors: O'day‐Bowman Mary B. , Mavrogianis Patricia A. , Fazleabas Asgerally T. , Verhage Harold G.
Published: February 2005

The major objective of this study was to examine the hormonal regulation of a human oviduct‐specific glycoprotein (huOGP) throughout the menstrual cycle and in all regions of the human oviduct. Regulation of synthesis and secretion was examined at both the protein (Western immunoblots and immunocytochemistry) and mRNA (Northern and slot blots) levels and correlated with changes in the morphological features of the oviductal epithelial cells throughout the cycle. Immunoblot analysis of oviductal fluid and explant culture media from all regions of the oviduct demonstrated that huOGP is primarily found during the follicular stage of the cycle and is not present in serum, follicular fluid, or uterine endometrium. Moreover, two‐dimensional (2‐D) immunoblots showed that all major isoelectric variants of huOGP observed on 2‐D fluorographs are immunologically related. Light microscopic immunocytochemistry localized huOGP to oviductal secretory cells in both ampulla and isthmic regions, with the most intense immunoperoxidase staining seen in midcycle samples. Using an indirect immunogold technique at the electron microscopic level, huOGP was specifically localized to secretory granules of the ampullary and isthmic nonciliated epithelial cells. The ultrastructural characteristics of these secretory cells during the mid to late follicular phase of the cycle suggested elevated protein synthetic activity. In addition, mRNA expression for huOGP was elevated in all regions of the oviduct in midcycle specimens. Collectively, these data indicate that huOGP is a major tissue‐specific, stage‐specific secretory product of the human oviduct during the periovulatory stage of the cycle and support the hypothesis that huOGP synthesis and secretion may be regulated by fluctuations in the levels of estrogen and progesterone. © 1995 Wiley‐Liss, Inc.