bluuebunny/crossref_metadata_2025 huggingface dataset:
Biological stereology: History, present state, future directions
Authors: Bolender Robert P.
Published: February 2005

The development of a quantitative structural platform for experimental biology—extending across a hierarchy of sizes ranging from molecules to organisms—has been punctuated by a series of major achievements over the last 30 years. Stereology, a form of quantitative morphology, has contributed handsomely to this success. A personal view is presented highlighting key events in the development of biological stereology. We also examine stereology with a view toward future developments in biology and speculate how stereology might contribute to the new biological infrastructure currently being built with computers. © 1992 Wiley‐Liss, Inc.
The influence of lens chromatic aberration on electron energy‐loss spectroscopy quantitative measurements
Authors: Yang Ying‐Ying , Egerton Raymond F.
Published: February 2005

An investigation has been made into the effect of chromatic aberrations of a pre‐spectrometer lens system on quantitative elemental analysis by electron energy loss spectroscopy (EELS). In transmission electron microscopy (TEM) diffraction mode, the measured effects are typically 150–330 times larger than if only objectiv‐lens chromatic aberration were important. We discuss several methods of avoiding errors arising from chromatic aberration, including selection of a suitable optical mode (dependent on the desired spatial resolution), adjustment of the TEM imaging system so as to focus the system for a chosen energy loss, and analysis of a large area of a uniform specimen. © 1992 Wiley‐Liss, Inc.
Role of the cytoskeleton during early development
Authors: Bement William M. , Ian Gallicano G. , Capco David G.
Published: February 2005

Oocytes, eggs, and embryos from a diverse array of species have evolved cytoskeletal specializations which allow them to meet the needs of early embryogenesis. While each species studied possesses one or more specializations which are unique, several cytoskeletal features are widely conserved across different animal phyla. These features include highly‐developed cortical cytoskeletal domains associated with developmental information, microtubule‐mediated pronuclear transport, and rapid intracellular signal‐regulated control of cytoskeletal organization. © 1992 Wiley‐Liss, Inc.
The aesthetasc concept: Structural variations of putative olfactory receptor cell complexes in crustacea
Authors: Hallberg Eric , Johansson Kjell U. I. , Elofsson Rolf
Published: February 2005

The structure of the aesthetascs has been investigated in the prawn Macrobrachium rosenbergii (larvae and juveniles), the opossum shrimp Neomysis integer, the euphausid Meganyctiphanes, and in the water‐fleas Daphnia magna and D. longispina. The aesthetascs, that are thought to represent olfactory receptors, exhibit a considerable structural variation, ranging from the well known aesthetascs of higher crustaceans (lobster, crab, crayfish) to the corresponding sensilla found in the water‐fleas and the males of opossum shrimps. The two following morphological characteristics of the aesthetascs are thought to indicate an olfactory function: the shape of the cuticular hair that is long and essentially hose‐shaped, and the thin, loosely arranged cuticle of at least the outer part of the cuticular hair. The presence of other structural elements such as sensory cells, cilia, and enveloping cells are vital for the olfactory function, but the development is variable, which makes their use in the morphological definition of aesthetascs problematic. © 1992 Wiley‐Liss, Inc.
Fine structure of a developing insect olfactory organ: Morphogenesis of the silkmoth antenna
Authors: Keil Thomas A.
Published: February 2005

The olfactory organ of the silkmoth Antheraea polyhemus is the feathered antenna which carries about 70,000 olfactory sensilla in the male. It develops within 3 weeks from a leaf‐shaped epidermal sac by means of segmental primary and secondary indentations which proceed from the periphery towards the centerline. During the first day post‐apolysis, the antennal epidermis differentiates into segmentally arranged, alternating sensillogenic and non‐sensillogenic regions. Within the first 2 days post‐apolysis, the anlagen of olfactory sensilla arise from electron‐dense mother cells in the sensillogenic epidermis. The axons of the developing sensilla begin to form the primary innervation pattern during the second day. The sensilla develop approximately within the first 10 days to their final shape, while the indentations are completed during the same period of time. The indentations are most probably driven by long basal extensions of epidermal cells, the epidermal feet. Primary indentations follow the course of segmentally arranged tracheal bundles and form the segments of the antenna. The secondary indentations follow the course of the primary segmental nerves which are reconstructed by this process. During the remaining time of development, the cuticle of the antenna and the sensory hairs is secreted by the epidermal and the hair‐forming cells. © 1992 Wiley‐Liss, Inc.
Growth of olfactory epithelial tissue in vitro: Lectin staining of axons
Authors: Farbman Albert I. , Buchholz Judith A.
Published: February 2005

In vitro methods have been used to study several aspects of development of olfactory epithelium. In this paper, the value of growing olfactory tissue in explant cultures is reviewed and some experiments are reported on the identification of lectin receptors on olfactory axons by the use of lectin‐gold complexes. Both concanavalin A‐gold (con A‐gold) and wheat germ agglutinin‐gold consistently decorated olfactory axons in explant cultures. Con A‐gold also bound to the tips of growth cone filopodia, suggesting the glycoconjugate molecules containing α‐methyl‐pyranoside are important in adherence of growth cones to their substrate. The wide range in density of lectin‐gold particles suggested that axons, and the sensory cells from which they arise, are not a uniform population, i.e., they have different molecular fingerprints. This was supported by the observation that soybean agglutinin‐gold stained some axons very well, but others remained unstained. Peanut agglutinin did not bind to any axons. © 1992 Wiley‐Liss, Inc.
Preparation of cross‐section specimens for transmission electron microscopy from α‐Al2O3/Ni solid state bonded bicrystal interfaces
Authors: Wan Chuangeng , Dupeux Michel
Published: February 2005

The technique which is described combines the advantages of the techniques formerly proposed in the literature in each stage of the preparation of transmission electron microscopy (TEM) specimens including a single metal‐ceramic interface. It allows easy handling of the thin foils in spite of their brittleness. Preferential thinning of the softer material in the two‐phase foil is prevented, and both sides of the interface are thinned down to comparable thicknesses. The nickel‐alumina bicrystal interface observed in TEM is neat and free from any reaction layer. This method is easily adaptable to other metal‐ceramic systems. © 1992 Wiley‐Liss, Inc.
Electron microscopy of Golgi‐impregnated interneurons: Notes on the intrinsic connectivity of the cerebral cortex
Authors: Fairén Alfonso , Smith‐Fernández Aníbal
Published: February 2005

The Golgi‐electron microscope technique has opened new avenues to explore the synaptic organization of the brain. In this article, we shall discuss basic methodological principles necessary to analyze axonal arborizations with this combined technique. To illustrate the applications of the method, we shall review the forms and distribution of the synapses in which the axonal arborizations of local cortical interneurons engage. © 1992 Wiley‐Liss, Inc.
Application of the Golgi/electron microscopy technique for cell identification in immunocytochemical, retrograde labeling, and developmental studies of hippocampal neurons
Authors: Frotscher M.
Published: February 2005

In this study the Golgi/electron microscopy (EM) technique has been used for an analysis of the fine structure, specific synaptic connections, and differentiation of neurons in the hippocampus and fascia dentata of rodents. In a first series of experiments the specific synaptic contacts formed between cholinergic terminals and identified hippocampal neurons were studied. By means of a variant of the section Golgi impregnation procedure, Vibratome sections immunostained for choline acetyltransferase, the acetylcholine‐synthesizing enzyme, were Golgi‐impregnated in order to identify the target neurons of cholinergic terminals in the hippocampus. It could be shown with this combined approach that cholinergic septohippocampal fibers form a variety of synapses with different target structures of the Golgi‐impregnated and gold‐toned hippocampal neurons. In this report cholinergic synapses on the heads of small spines, the necks of large complex spines, dendritic shafts, and cell bodies of identified dentate granule cells are described. The variety of cholinergic synapses suggests that cholinergic transmission in the fascia dentata is a complex event.

Next, the Golgi/EM technique was applied to Vibratome sections that contained retrogradely labeled neurons in the hilar region of the fascia dentata following horseradish peroxidase (HRP) injection into the contralateral hippocampus. With this combined approach some of the hilar cells projecting to the contralateral side were identified as mossy cells by the presence of retrogradely transported HRP in thin sections through these Golgi‐impregnated and gold‐toned neurons. Our findings suggest that the mossy cells are part of the commissural/associational system terminating in the inner molecular layer of the fascia dentata. They are mainly driven by hilar collaterals of granule cell axons that form giant synapses on their dendrites.

Finally, the Golgi/EM procedure was used to study the differentiation and developmental plasticity of hippocampal and dentate neurons in transplants and slice cultures of hippocampus. Under both experimental conditions, the differentiating neurons are deprived of their normal laminated afferent innervation but develop their major cell‐specific characteristics including a large number of postsynaptic structures (spines). As revealed in thin sections of gold‐toned identified cells, all these spines formed synapses with presynaptic boutons suggesting sprouting of the transplanted and cultured neurons, respectively.

Altogether, the present report demonstrates the usefulness of the Golgi/EM technique, particularly of the section impregnation procedure, for a variety of studies requiring the identification of individual neurons at the ultrastructural level. © 1992 Wiley‐Liss, Inc.
Quantitative aspects of synapses on Golgi‐impregnated neurons
Authors: Müller Linda J. , Cardozo Bob Nunes , Vrensen Gijs F. J. M.
Published: February 2005

With the classical Golgi techniques, numerous types of neurons can be distinguished in the cerebral cortex, each with a specific dendritic geometry and pattern of axonal ramifications. In the present review we describe two techniques which allow quantification of synapses on identified neurons: (1) Golgi‐rapid impregnation‐gold toning‐electron microscopy, and (2) Golgi‐Kopsch impregnation‐gold toning‐electron microscopy in combination with staining of the tissue with ethanolic phosphotungstic acid (E‐PTA). Both techniques were applied on neurons in the visual cortex of young and adult rabbits. By means of rotating and tilting specimens in the electron microscope, the nondistinctive ultrastructure of obliquely sectioned synapses can be circumvented, leading to precise estimates of asymmetrical vs. symmetrical synapses without complete reconstruction of the neuron. © 1992 Wiley‐Liss, Inc.
Simulation of dislocations imaged moiré fringe contrast
Authors: Angelo James E. , Gerberich W. W.
Published: February 2005

Transemission electron microscope (TEM) images of dislocations as produced via moiré fringe contrast are simulated using many‐beam diffraction theory. The effect of edge dislocations on both parallel and rotational moiré fringe patterns is considered. For the parallel moiré fringe pattern, images of dislocations both perpendicular to the film plane and those inclined to the film plane are produced. The effect of an inclined dislocation is shown to cause a distortion of the dislocation image. Finally, a comparison between predicted and experimentally observed images is made, with the results indicating that threating dislocations in the FeAl/GaAs system have line directions nearly perpendicular to the (001)FeAl/GaAs film plane. © 1993 Wiley‐Liss, Inc.
Cellular organization and growth‐related plasticity of the crayfish olfactory midbrain
Authors: Mellon Deforest , Alones Vinessa
Published: February 2005

Little knowledge is available concerning the detailed anatomy of the crusctacean central olfactory pathway. We are using radiolabeling, Golgi and biocytin/neurobiotin tracer methodologies, at the correlated light and electron microscopical levels, to study the olfactory midbrain of the freshwater crayfish. We have found that primary afferent fibers from the antennular olfactory receptor cells branch extensively throughout the length of the glomerular columns within the olfactory lobes in the midbrain. Globuli cells of the lateral cell clusters ramify as dendritic arborizations within both the olfactory and accessory lobes; their axons project out the olfactory‐globular tracts to the lateral protocerebrum, often branching to both sides. Developmental plasticity involving the connections made by afferent fibers within the olfactory lobes may permit detailed examination of organizational changes within the midbrain as the animal grows and adds new afferent input from the periphery. © 1993 Wiley‐Liss, Inc.
Electron microscopy of materials at the university of Birmingham
Authors: Jones I. P. , Loretto M. H. , Smallman R. E.
Published: February 2005

The School of Metallurgy and Materials has traditionally put transmission electron microscopy (TEM) in the forefront of its research interests and, through support from SERC and from the university, has always had the facility to carry out state of the art electron microscopy of materials. In this brief review some of the topics where TEM has played a central role in recent work in Birmingham will be described so that it will be seen just how central to the work in Birmingham TEM has been. © 1993 Wiley‐Liss, Inc.
Rapid fixation and embedding method for immunocytochemical studies of tomato spotted wilt tospovirus (TSWV) in plant and insect tissues
Authors: Westcot Daphne M. , Ullman Diane E. , Sherwood John L. , Cantone Frank A. , German Thomas L.
Published: February 2005

A new rapid fixation and embedding technique using microwave energy was evaluated for immunolabelling and examination of ultrastructure of plant and insect cells. Tissues in gluteraldehyde‐paraformaldehyde were fixed for fifteen seconds in a microwave at 100% power, and dehydrated. Microwave energy was then used to polymerize the London Resin White (LR White) acrylic resin during the embedding process. Embedded specimens were then thin sectioned (90 nm) and treated with anti‐tomato spotted wilt tospovirus (TSWV) antiserum followed by protein A‐gold label, or antisera against a TSWV encoded nonstructural protein followed by goat anti‐rabbit gold label. Using this technique, structural and nonstructural proteins of TSWV were readily detected and specifically labelled in cells of the insect vector, the western flower thrips, Frankliniella occidentalis (Pergande), and in infected cells of the plant species, Emilia sonchifolia L. © 1993 Wiley‐Liss, Inc.
Protocol of electron microscope in situ nucleic acid hybridization for the exclusive detection of double‐stranded DNA sequences in cells containing large amounts of homologous single‐stranded DNA and RNA sequences: Application to adenovirus type 5 infected Hela cells
Authors: Puvion‐Dutilleul Francine
Published: February 2005

In order to gain a further insight into the relationships of the complex process of replication of adenovirus genomes to the substructures which occur in the nuclei of adenovirus type 5 (Ad5) infected HeLa cells, we have visualized directly, at the electron microscopic level, viral double‐stranded DNA (dsDNA) in late infected nuclei by the use of a post‐embedding in situ hybridization technique with a biotinylated specific DNA probe. The procedure is based on the removal of single‐stranded (ss) nucleic acids by S1 nuclease. The highest levels of signal density for viral dsDNA were detected over the fibrils of the large, centrally located viral genome storage site and over the viral nucleoids of both clustered and isolated viruses. Lower but significant signals were observed over the fibrillo‐granular network of the peripheral replicative zones, where both transcription and replication of viral DNA occur. On the other hand, the labeling of the enclosed viral ssDNA accumulation sites, also involved in viral replication but not transcription, was negligible, which suggests that, in the latter, the newly synthesized viral dsDNA immediately extends into the adjacent peripheral replicative zone to be transcribed and/or replicated.
Immunohistochemical markers of uterine receptivity in the human endometrium
Authors: Ilesanmi Abiodun O. , Hawkins Denise A. , Lessey Bruce A.
Published: February 2005

The factors responsible for the initial interaction between maternal and fetal epithelium leading to the establishment of pregnancy remain poorly understood. Temporal and spatial expression of specific endometrial peptides in response to ovarian steroids is thought to contribute to the development of a period of uterine receptivity, whereby the endometrium becomes hospitable to the implanting blastocyst. The failure to establish receptivity may account for a significant percentage of the cases of infertility in the female, especially affecting women with luteal phase deficiency, leiomyomata uteri, endometriosis, habitual abortion, and unexplained infertility. In addition, despite increasing global experience with advanced reproductive technologies, the majority of In Vitro Fertilization (IVF) attempts remain unsuccessful, most likely on the basis of implantation failure. In this article, we review the concepts involved in the study of uterine receptivity in the human, highlight potential immunohistochemical (IHC) markers that have recently been discovered, and discuss how IHC assessment of the endometrium is a potentially valuable method for the evaluation of the receptive endometrial state. Using this approach we have examined several new potential markers of uterine receptivity. Endometrial progesterone receptors and one of the integrin cell adhesion molecules appear to undergo changes in expression around the time of implantation, and may be sensitive indicators of the receptive state. Further, these markers are delayed in women with infertility and luteal phase deficiency. These studies illustrate the utility of IHC diagnosis for the evaluation of endometrial function. © 1993 Wiley‐Liss, Inc.
Uterine cell death during implantation and early placentation
Authors: Welsh Alerick O.
Published: February 2005

During blastocyst implantation and placentation in common laboratory rodents, trophoblast cells come into increasingly more intimate associations with the endometrium and, eventually, are in contact with maternal blood. Uterine cell death is one mechanism for removing uterine tissues, primarily epithelial cells, and decidual cells that intervene between trophoblast cells and maternal blood. Mechanisms of cell death and the signals that initiate and regulate it are not well understood. According to current theories, cell death is either gene‐directed or the result of traumatic injury, and classification of cell death is based on ultrastructural and biochemical criteria that hypothetically reflect underlying molecular mechanisms. Although the term apoptosis is extensively used to describe all aspects of gene‐directed cell death and the term necrosis to describe traumatic death, ultrastructural studies indicate that there are morphological variations of the established criteria, and these could reflect variations of underlying mechanisms. Recent light and electron microscopic work has shown that timing and ultrastructure of uterine cell death at the gestation site varies with region suggesting that initiation and control of cell death is complicated and that more than one mechanism of cell death may be operative. Current information indicates that uterine cell death is most likely part of an intrinsic response of the endometrium to the conceptus, and other than acting as a stimulus to elicit the uterine response, the conceptus probably plays only a minor role in regulating the death of endometrial cells in these species. © 1993 Wiley‐Liss, Inc.
Software for counting cells and estimating structural volumes with the optical disector and fractionator
Authors: Bolender Robert P. , Charleston Jay S.
Published: February 2005

We describe MS‐DOS software for the optical volume fractionator (OVF), a stereological method combining the principles of the optical disector (Gundersen et al.: Acta Pathol. Microbiol. Immunol. Scand., 96:857–881, 1988) and fractionator (Gundersen: J. Microsc., 143:3–45, 1986). The OVF program estimates the volume of a fixed and embedded structure, the numerical density of cells, and the total number of cells in a structure. The hardware requirements include a PC computer (386 or 486 with VGA graphics) and a conventional light microscope fitted with a rotating stage, extension tube, and length gauge. The software includes an introduction, tutorial, simulator, laboratory toolkit, and report generator. The toolkit improves the efficiency of gathering stereological data with light microscopy and offers a convenient link between the data of light and electron microscopy. A novel algorithm, based on fractionator sampling, gives the volume of a fixed and embedded structure from the same set of sections used for cell counting. A laboratory example illustrates the operation of the software. © 1993 Wiley‐Liss, Inc.
Inner architecture of human and simian immunodeficiency viruses
Authors: Fukui Takeshi , Imura Shunro , Goto Toshiyuki , Nakai Masuyo
Published: February 2005

The cores of human and simian immunodeficiency viruses (HIV and SIV) were observed by negative staining after isolation of the core with Nonidet P40 and glutaraldehyde. Four kinds of cores were found: asymmetric and symmetric sectoral shapes, a bar shape, and a triangular shape. These results were confirmed by the examination of ultrathin sections of whole virions. In some virions, the connection between the core and the envelope was observed after freeze fracturing. Its structure was considered to be characteristic of an intermediate stage of viral maturation. The HIV‐1 core was reacted with anti‐HIV‐1 p24 mouse monoclonal antibody. © 1993 Wiley‐Liss, Inc.
Introduction to the ESEM instrument
Authors: Danilatos G. D.
Published: February 2005

An outline is presented of the first commercial environmental scanning electron microscope (ESEM). A concise description of this instrument and its operation, from a user's perspective, is given. More specifically, the description includes the electron optics, pressure stages and control, detection modes, resolution, and ancillary equipment. © 1993 Wiley‐Liss, Inc.
Environmental scanning electron microscope imaging examples related to particle analysis
Authors: Wight Scott A. , Zeissler Cynthia J.
Published: February 2005

This work provides examples of some of the imaging capabilities of environmental scanning electron microscopy applied to easily charged samples relevant to particle analysis. Environmental SEM (also referred to as high pressure or low vacuum SEM) can address uncoated samples that are known to be difficult to image. Most of these specimens are difficult to image by conventional SEM even when coated with a conductive layer. Another area where environmental SEM is particularly applicable is for specimens not compatible with high vacuum, such as volatile specimens. Samples from which images were obtained that otherwise may not have been possible by conventional methods included fly ash particles on an oiled plastic membrane impactor substrate, a one micrometer diameter fiber mounted on the end of a wire, uranium oxide particles embedded in oil‐bearing cellulose nitrate, teflon and polycarbonate filter materials with collected air particulate matter, polystryene latex spheres on cellulosic filter paper, polystyrene latex spheres “loosely” sitting on a glass slide, and subsurface tracks in an etched nuclear track‐etch detector. Surface charging problems experienced in high vacuum SEMs are virtually eliminated in the low vacuum SEM, extending imaging capabilities to samples previously difficult to use or incompatible with conventional methods. © 1993 Wiley‐Liss, Inc.
Advantages of environmental scanning electron microscopy in studies of microorganisms
Authors: Collins Scott P. , Pope Robert K. , Scheetz Raymond W. , Ray Richard I. , Wagner Patricia A. , Little Brenda J.
Published: February 2005

Microorganisms, including bacteria, fungi, protozoa, and microalgae, are composed predominantly of water which prohibits direct observation in a traditional scanning electron microscope (SEM). Preparation for SEM requires that microorganisms be fixed, frozen or dehydrated, and coated with a conductive film before observation in a high vacuum environment. Sample preparation may mechanically disturb delicate samples, compromise morphological information, and introduce other artifacts. The environmental scanning electron microscope (ESEM) provides a technology for imaging hydrated or dehydrated biological samples with minimal manipulation and without the need for conductive coatings.

Sporulating cultures of three fungi, Aspergillus sp., Cunninghamella sp., and Mucor sp., were imaged in the ESEM to assess usefulness of the instrument in the direct observation of delicate, uncoated, biological specimens. Asexual sporophores showed no evidence of conidial displacement or disruption of sporangia.

Uncoated algal cells of Euglena gracilis and Spirogyra sp. were examined using the backscatter electron detector (BSE) and the environmental secondary electron detector (ESD) of the ESEM. BSE images had more clearly defined intracellular structures, whereas ESD gave a clearer view of the surface. E. gracilis cells fixed with potassium permanganate, Spirogyra sp. stained with Lugol's solution, and Saprolegnia sp. fixed with osmium tetroxide were compared using BSE and ESD to demonstrate that cellular details could be enhanced by the introduction of heavy metals. The effect of cellular water on signal quality was evaluated by comparing hydrated to critical point dried specimens. © 1993 Wiley‐Liss, Inc.
Microanalytical studies of metal localization in biological tissues by environmental SEM
Authors: Egerton‐Warburton Louise M. , Griffin Brendon J. , Kuo John
Published: February 2005

The presence and distribution of Al and Mn in floral and seed tissues of eucalypts from Al‐contaminated soils was analyzed using energy‐dispersive X‐ray microanalysis (EDS) in an environmental scanning electron microscope (ESEM). EDS by ESEM determined the distribution of elements between tissue types was suitable for intact samples or those with lower available moisture or intact specimens. The analytical technique was not appropriate for highly vascular samples. Other factors influencing the detection of elements by ESEM‐EDS were electron scattering and the relative concentration and localization of elements within the tissues. EDS‐detectable levels were significantly correlated with tissue concentrations determined by atomic absorption spectrophotometry for Mn but not for Al. © 1993 Wiley‐Liss, Inc.
An introduction to process visualization capabilities and considerations in the environmental scanning electron microscope (ESEM)
Authors: Prack Edward R.
Published: February 2005

Process visualization can be a very powerful tool for understanding dynamic processes. Process visualization requires a non‐destructive technique that can be monitored in real time. In this paper various methods of non‐destructive inspection will be described and compared. The applicability of these non‐destructive inspection methods to process visualization will be compared and contrasted. Particular attention will be paid to a recent development in this area, the environmental scanning electron microscope (ESEM) which is inherently a non‐destructive inspection technique with the advantages of electron microscopy for superior magnification and depth of field capability. The ESEM offers a unique platform for process visualization studies. The majority of process visualization is currently done using optical microscopes with hot stages for observing morphological effects top down (optical microscopes) or from the side (contact angle). Major limitations of these optical methods include lack of magnification, poor depth of field, and clouding of optics.

Process visualization is best carried out utilizing a non‐destructive technique, such as the ESEM, since invasive sample preparation techniques such as conductive coatings alter the sample and make interpretation more difficult. Common process variables such as thermal profiling and the effect of ambient conditions have been examined using the ESEM. Other process variables that could be of interest in the future will be discussed. There are limitations in the ability of the ESEM to reproduce actual process conditions, such as pressure and mass flow rate trade‐offs. The ESEM can also be combined directly and indirectly with other analytical techniques to determine the composition of the sample and/or byproducts of a reaction that is being monitored.

This paper will serve as an overview and introduction for several papers which deal in depth with specific process visualization applications which utilize the ESEM. A series of illustrative examples of previous work will be referenced and briefly discussed. The examples will emphasize the importance of non‐destructive testing techniques in material science and semiconductor applications. The application window of the ESEM for process visualization will be explored, including trade‐offs in process conditions that can be examined. Observation of dynamic processes include examples such as corrosion studies of various materials such as stainless steel and thermal studies of industrially relevant processes such as ceramic processing, soldering, and sealing. Morphological and compositional process visualization applications will be presented. An example of morphological applications observed is solder reflow and intermetallic formation as a function of the materials used and the atmosphere during processing. Morphological coupled with compositional applications include monitoring outgassing products from solder paste and Ag/glass die attach material. © 1993 Wiley‐Liss, Inc.
Bibliography of environmental scanning electron microscopy
Authors: Danilatos G. D.
Published: February 2005

Two updated lists of publications on environmental scanning electron microscopy are compiled. One list contains mainly those papers dealing with the development and instrumentation, while the other deals mainly with the applications of the technique. A brief introductory summary of the field is presented. © 1993 Wiley‐Liss, Inc.
The innervation of salivary glands as revealed by morphological methods
Authors: Garrett John R. , Kidd Audrey
Published: February 2005

Salivary secretion is nerve mediated. The salivary glands are supplied by parasympathetic and sympathetic efferent nerves which travel to the glands by separate routes. Once in the glands the axons from each type of nerve intermingle and travel together in association with Schwann cells, forming Schwann‐axon bundles. Two types of neuro‐effector relationships exist with salivary parenchymal and myoepithelial cells: epilemmal (outside the parenchymal basement membrane) and hypolemmal (within the parenchymal basement membrane). Their relative frequencies with either type of nerve differ greatly between glands and species. Salivary blood vessels receive epilemmal innervations by both sympathetic and parasympathetic axons. The classical transmitters—acetylcholine in parasympathetic and noradrenaline in sympathetic axons—are stored in small vesicles. A variety of non‐conventional neuropeptide transmitters have also been found in salivary nerves by immunohistochemistry, and they occur in large dense‐cored vesicles. Prolonged high frequency stimulation has been found to cause depletion of large dense‐cored vesicles from glandular nerves. In recent years afferent nerves have started to be identified and are found in greatest numbers around the main salivary ducts, where they may form a hypolemmal association with the epithelial cells. Functional studies demonstrate complex interactions between parasympathetic and sympathetic nerves. Morphological assessments of changes in the parenchymal cells after nerve stimulations or denervations add greatly to our understanding of the nerve functions. At least four types of influence can be exerted on salivary parenchymal cells by the nerves: hydrokinetic (water mobilizing), proteokinetic (protein secreting), synthetic (inducing synthesis), and trophic (maintaining normal functional size and state). In respect to each role, wide glandular and species differences exist between the relative contributions made by each type of nerve. © 1993 Wiley‐Liss, Inc.
Evolutionary modifications of morphogenetic mechanisms and alternate life history strategies in ascidians
Authors: Bates William R.
Published: February 2005

Comparative embryological studies using anural and urodele ascidians provide an experimental system to study interactions between developmental and evolutionary mechanisms that produce alternate life history strategies. In this paper, cellular features of anural morphogenesis in Molgula pacifica are compared to morphogenesis in species that develop tailed (urodele) larvae and other anural molgulid species. The results of these studies are discussed with regard to possible mechanisms responsible for the evolution of anural morphogenesis and the ecological consequences of anural development. Early developmental processes including ooplasmic segregation, cleavage patterns, and the site and timing of gastrulation were similar in M. pacifica compared to urodele embryos and embryos produced by other anural species. The limited extent of invagination caused by large, yolky cells that restricted vegetal pole cell movements in M. pacifica gastrulae contrasted with the extensive movements of vegetal pole cells that accompanied invagination in M. provisionalis embryos and the embryos of four urodele species. The modified mode of gastrulation exhibited by M. pacifica embryos is likely due to the relatively high yolk content of their eggs.

The developmental fates of muscle and epidermal progenitor cells in M. pacifica embryos were altered compared to urodele embryos. Ultrastructural studies and acetylcholinesterase histochemistry experiments indicate that muscle progenitor cells have lost their potential to develop muscle cell features. This loss in myogenic potential suggests that muscle progenitor cells were re‐programmed to die. However, this possibility was not supported by the results of ultrastructural studies. A second possibility is discussed in that muscle progenitor cells may have been re‐specified to differentiate into adult cells after metamorphosis. Evidence is presented suggesting that the timing mechanism responsible for controlling the onset of metamorphosis, first evident by the outgrowth of epidermal ampullae, was modified in M. pacifica. This paper concludes with a discussion of how anural morphogenesis altered the ancestoral urodele life cycle and the possible ecological benefits of these evolutionary alterations. © 1993 Wiley‐Liss, Inc.
Ultrastructural features of alveolar epithelial cells in the late fetal pulmonary acinus: A comparison between normal and hypoplastic lungs using a rat model of pulmonary hypoplasia and congenital diaphragmatic hernia
Authors: Brandsma Annelies E. , Tibboel Dick , Vulto Irma M. , Egberts Johannes , Ten Have‐Opbroek Ank A. W.
Published: February 2005

The aim of this study was to describe and compare the ultrastructural features and functional maturity of alveolar epithelial cells in hypoplastic and normal fetal rat lungs. Pulmonary hypoplasia in association with congenital diaphragmatic hernia was induced in fetuses by administration of 2,4‐dichlorophenyl‐p‐nitrophenylether (Nitrofen) to pregnant Sprague Dawley rats (100 mg on day 10 of gestation). Lung tissue of Nitrofen‐exposed and control fetal rats aged 19–22 days (vaginal plug day 1, birth day 23) was embedded in Epon. Semithin (1 μm) toluidine blue‐stained sections were examined by light microscopy; ultrathin sections (∼80 nm) were studied via transmission electron microscopy. In bronchoalveolar lavage fluid from control and Nitrofenexposed fetuses (day 22), phospholipid fractions and surfactant protein A content were measured semiquantitatively. On day 19 both control and Nitrofen‐exposed lungs contained only cuboid alveolar epithelial cells; from day 20 there were cuboid, low cuboid, and thinner epithelial cells. The (low) cuboid cells contained large glycogen fields, some precursory stages of multilamellar bodies (MLBs), and just a few mature MLBs on day 19 and 20; smaller glycogen fields, more precursory stages, and more mature MLBs on day 21; and little or no glycogen but many precursory stages and mature MLBs on day 22. The thinner cells contained little or no glycogen and a few precursory stages of MLBs on days 20–22; very thin cells on day 22 contained neither glycogen nor any precursory stages of MLBs. MLBs and tubular myelin were seen in the lumens of future air spaces from day 20 onward. Nitrofen‐exposed lungs differed from control lungs in that inclusion bodies (IBs) were less numerous in (low) cuboid alveolar cells on days 19 and 20, and more glycogen was seen on day 22. In addition intra‐ and extracellular “MLBs” in exposed lungs more often had an unusual appearance, i.e., a confluent structure and higher electron density. However, despite morphologic differences, there was no clear difference in phospholipid composition and SP‐A content per mol phospholipid in bronchoalveolar lavage fluid. We conclude that morphologically hypoplastic lungs are less mature near term, without an apparent effect on surfactant composition. © 1993 Wiley‐Liss, Inc.
New aspects of microvascular corrosion casting: A scanning, transmission electron, and high‐resolution intravital video microscopic study
Authors: Aharinejad Seyedhossein , MacDonald Ian C. , Mackay E. Carole , Mason‐Savas April
Published: February 2005

We used intravital microscopy of small intestine and pancreas in order to show dynamic interactions between vascular wall and undiluted Mercox, because previous studies of ours have shown that Mercox diluted with monomeric methylmethacrylate penetrates cells in the vascular wall. Scanning and transmission electron microscopy were used to show three‐dimensional pathways and correlating tissue structures, which cannot be identified in vivo. The microvascular diameters were not altered when the vasculature was flushed with saline/dextran solution using perfusion pressures between 70 and 140 mm Hg, but, in circumscribed areas, contraction of vascular wall was observed immediately after Mercox injection. This phenomenon was carried out by endothelial cells; pericytes were never present at the site of constrictions. Extravasation, i.e., leakage of the resin into the surrounding tissue, occurred in circumscribed areas regardless of the applied perfusion pressure. The resin also filled routes, which were not perfused with blood before casting. Scanning microscopy of corresponding specimens showed flattened cast channels, with impressions of valves and endothelial cell nuclear imprints characteristic of lymphatics. These results show that undiluted Mercox is a stimulus for vascular cellular components and that it changes the vascular wall permeability, resulting in extravasation and filling of lymphatics. Transmission electron microscopy showed that large vessels were homogeneously filled with resin and that cellular structures were not infiltrated with Mercox. Cut sections of the gold‐coated surface of casts showed grooves up to 20 nm wide, suggestive of minimal deformation, while the abluminal surface of the metal film was almost smooth. Another proof of minimal deformation of undiluted Mercox casts is that the diameter of vessels was not altered during and after polymerization. Obtained casts are not fragile, as are casts of diluted Mercox, and phase separation does not occur, which would result in penetration of the cells in the vascular wall. For these reasons, the use of undiluted Mercox is recommended. Mixing 10 ml Mercox with 1 g catalyst resulted in complete polymerization within 5.5–7 min. This mixture can be used for casting biological specimens. © 1993 Wiley‐Liss, Inc.
Myoepithelium of salivary glands
Authors: Redman Robert S.
Published: February 2005

In salivary glands and other exocrine organs, there are starfish‐shaped cells that lie between the basal lamina and the acinar and ductal cells. These have structural features of both epithelium and smooth muscle cells, and so are called myoepithelial cells. Their functions include contraction when the gland is stimulated to secrete, compressing or reinforcing the underlying parenchymal cells, thus aiding in the expulsion of saliva and preventing damage to the other cells. They also may aid in the propagation of secretory and other stimuli. Their common developmental origin with the basal cells of the larger ducts is displayed in the mature glands by shared structural and immunohistochemical features, but most such basal cells do not have the distinguishing features of myoepithelial cells, such as myofibrils. Although myoepithelial cells can be identified by light microscopy through enzyme histochemistry and special stains and immunohistochemistry for their myofibrils, these techniques can be misleading in salivary gland neoplasms. Thus, the most reliable means of identifying neoplastic myoepithelial cells is with a combination of histochemistry and electron microscopy. The extent to which these cells are derived from undifferentiated stem cells in both normal and neoplastic growth is controversial. The presentation here of transmission electron microscopy (TEM) of well‐differentiated myoepithelial cells in mitotic division indicates that stem cells are not necessarily the only source of myoepithelial cells in the later stages of salivary gland development or in neoplasia. © 1994 Wiley‐Liss, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America.
Patterns of intercellular connectivity in the mammalian cumulus‐oocyte complex
Authors: Albertini David F. , Rider Virginia
Published: February 2005

Electron and fluorescence microscopic techniques have been used in a complementary fashion to study the patterns of follicle cell‐oocyte interactions within cumulus‐oocyte‐complexes of various mammals. The principal findings are: (1) two distinct types of transzonal processes exist that are distinguishable on the basis of cytoskeletal composition; (2) in some of the species examined (pig, goat, primate), corkscrew‐shaped processes rich in tubulin, traverse the zona pellucida and are invaginated into the oocyte cortex; (3) actin‐rich processes either ramify as a network at the outer surface of the zona pellucida or penetrate the zona and make contact with the oolemma in a species specific manner. These results are discussed with respect both to the need to employ complementary optical methods in assessing connectivity patterns within COC and to the possible role that extracellular matrix‐cell interactions play in the homeostatic control of oocyte growth and maturation. © 1994 Wiley‐Liss, Inc.
Variations in mitochondrial ultrastructure and dynamics observed by high resolution scanning electron microscopy (HRSEM)
Authors: Lea Peter J. , Temkin Robert J. , Freeman Karl B. , Mitchell Grant A. , Robinson Brain H.
Published: February 2005

Rat adrenal cortex was processed for high resolution scanning electron microscopy (HRSEM) to confirm tubular cristae, reported by transmission electron microscopy to be present in cortex mitochondria. Mitochondria in several other tissue and cell types were also observed and their ultrastructure confirmed by using three‐dimensional, stereo, high resolution scanning electron microscopy. The mitochondria in rat and human hepatocytes as well as human skin fibroblasts mitochondria proved to be long, up to 46 micrometers and branching, as compared to those in liver which were spherical in shape. Cold adapted brown fat cells were packed with mitochondria, these containing plate or shelf‐like cristae. Branched, rat striated muscle mitochondria were observed to curve around contractile protein filament bundles. The muscle mitochondrial cristae were found to be both tubular and plate‐like, within the same mitochondrion. The ratio of tubular cristae to plate‐like cristae varied considerably between muscle mitochondria. In order to use ultrastructural changes in mitochondria for differential diagnosis, and because 3D reconstruction of mitochondria based on transmission electron microscopy serial sections is severely limited in resolution, it is imperative to first develop a correct understanding of tissue specific, normal mitochondrial ultrastructure based on three‐dimensional, HRSEM methods. © 1994 Wiley‐Liss, Inc.
Electron microscopy of the F1F0 ATP synthase: From structure to function
Authors: Gogol Edward Peter
Published: February 2005

The 1F0 ATP synthase is the large multisubunit complex which uses the proton gradient of energetically active membranes to synthesize ATP. While biochemical and genetic approaches have characterized the composition of the enzyme and elucidated many details of its mechanism and assembly, electron microscopy has been the tool of primary importance in determining the arrangement of the many subunits which comprise the F1F0. The highly cooperative catalytic mechanism is tightly coupled to transmembrane proton translocation in a separate and rather distant sector of the complex. An understanding of this intricate process and its control requires an appreciation of subunit interactions, starting with their locations relative to one another. Electron microscopy has provided most of the available structural information on the F1F0, and recent applications of cryo‐electron microscopy have captured different functionally relevant configurations which may finally address longstanding questions about subunit rearrangement during the catalytic cycle. © 1994 Wiley‐Liss, Inc.