bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acetonitrile as a substitute for ethanol/propylene oxide in tissue processing for transmission electron microscopy: Comparison of fine structure and lipid solubility in mouse liver, kidney, and intestine
Authors: Edwards Harold H. , Yeh Yu‐Yan , Tarnowski Betty I. , Schonbaum Gregory R. 
Published: February 2005

AbstractTissue processing for transmission electron microscopy (TEM) is commonly accomplished using ethanol (EtOH) as a dehydrating solvent and propylene oxide (PO) as a transition fluid. Both solvents have some undesirable properties: EtOH solubilizes lipids; PO is highly flammable, volatile, toxic, and potentially carcinogenic. Their replacement by a compound devoid of these characteristics is therefore desirable. Acetonitrile (AN) appears to be such a solvent. It is freely miscible with water, alcohols, acetone, and epoxy resins; it does not interfere with epoxy polymerization; and the resulting cured resins have excellent cutting quality and beam stability. AN is also an excellent dehydrating agent whose use does not necessitate modification of current techniques. Most importantly, the low solubility of phospholipids (PL) in AN limits the loss of membrane lipids and, hence, leads to a better preservation of tissue features.
Observation by transmission electron microscopy of etch figures obtained on an organic molecular crystal
Authors: Mercier Michel , Raimi Mohamed Karim , Bonpunt Louis 
Published: February 2005

AbstractIt is interesting to apply the method of etch figures to the study of organic molecular crystal defects, by observing the etch pits as soon as they are produced. We have set up a method to determine the geometrical forms of such small etch pits, observed on pre‐shadowed replicas of naphthalene crystal surfaces. The described experimental procedure was designed to avoid artefacts due to vacuum sublimation and moisture traces on the replicated surface. Stereoscopic observation makes interpretation possible. The 3‐D morphology and size of etch figures smaller than 1 μm can be determined.
Pinealocyte synaptic ribbons and neuroendocrine function
Authors: McNulty John A. , Fox Linda M. 
Published: February 2005

AbstractA comparative study of pinealocyte synaptic ribbons (SR) revealed two predominant populations exhibiting either a rod/ribbon shape (SRr) or a spherical/punctate shape (SRsp). Species‐specific differences were found in the abundance of SR, the ratio of SRr/SRsp, and the occurrence of SR in ribbon fields. The close topographical relationship of SR to the plasma membrane and the numerical changes that occurred with changes in metabolism of the pinealocytes suggest that SR have important vesicle‐mediated interactions with the cell membrane. Experiments designed to clarify the relationship between SR and pineal neuroendocrine function revealed a positive correlation between SR numbers and indole intermediates during pineal development in the rat, and increased SR frequency after denervation of the rat pineal gland or administration of the β‐adrenergic agonist, isoproterenol. These data are consistent with the hypothesis that SR function is linked to receptor mechanisms regulating indoleamine production in the pineal gland. © 1992 Wiley‐Liss, Inc.
Third ventricular pineal gland grafts in the gerbil: An electron microscopical and immunohistochemical investigation
Authors: Welsh Marcia G. , Li Kang 
Published: February 2005

AbstractThe superficial pineal gland was grafted into the third ventricle of adult mongolian gerbils. Donor pineal glands from both neonatal and 3–4 week old gerbils were able to survive for at least 6 months. The pinealocytes of the grafted superficial pineal glands maintained the morphology and the S‐antigen immunoreactivity of the in situ pineal complex. Synaptic ribbons and spherules were present but rare. Unlike the in situ pinealocytes, glycogen accumulations were common in the graft pinealocytes. Site specific modulation of structure was indicated as the ventricular surface of the grafts became covered with cerebrospinal fluid (CSF)‐contacting pinealocytes typical of those seen in the deep pineal. The CSF‐contacting pinealocytes of the graft had numerous processes that extended along the ventricular surface of the graft. The blood vessels of the grafts had non‐fenestrated endothelium and wide perivascular areas typical of those seen in the in situ pineal complex. Tyrosine hydroxylase‐immunopositive nerve fibers were present in the grafted tissue indicating reinnervation of the graft. The source of the fibers was not determined. The nerve fibers were present both within the perivascular area and within the parenchyma where they were associated with pinealocytes. The results demonstrate that the cerebral ventricles are an ideal location for the survival of superficial pineal gland grafts. It is suggested that pineal grafts may be a means to further study pineal development and innervation. © 1992 Wiley‐Liss, Inc.
Quantitative perimeter and area measurements of digital images
Authors: Barba Joseph , Chan Kin S. , Gil Joan 
Published: February 2005

AbstractQuantitative estimations of perimeter and area from digitized video images, and the application of these features in morphometry, are discussed. Estimations from manual tracings via interactive peripherals and from chain codes are addressed. Topics discussed are calibration, determination of vertical and horizontal pixel resolution, effects of tracing jitter, and for chain codes, the spatial quantization scheme representation of the digital contour. Finally, new perimeter estimators for 4‐connected and 8‐connected chain codes for non‐unity pixel aspect ratio are presented with simulation results.
Quantitative morphology for biologists and computer scientists: I. Computer‐aided tutorial for biological stereology (version 1.0)
Authors: Bolender Robert P. 
Published: February 2005

AbstractThis paper describes a computer‐aided tutorial for biological stereology. Stereology, a type of quantitative morphology, includes a collection of statistical methods that quantify the structural compartments that can be viewed in sections with light and electron microscopy. These methods provide volume, surface, length, shape, and number data, and help define the quantitative relationships among the structural compartments of biological hierarchies. Hierarchies, which connect structural data ranging in size from molecules to organs, serve as a central core to which the data of biological databases can be linked. The tutorial focuses on two objectives. It provides the user primarily interested in using quantitative morphology databases with background information, and offers a set of state‐of‐the‐art tools to researchers wishing to use these methods in the laboratory. The main topics of the tutorial include: introduction to quantitative morphology, symbols/terms, data types, sampling, hierarchies, data interpretation, and utilities. The tutorial runs under the MS‐DOS operating system and requires at least an IBM PC AT (or compatible), a color monitor (EGA, VGA), 540 KB of RAM, and 3 MB of hard disk space. © 1992 Wiley‐Liss, Inc.
Deployment of extracellular matrix proteins in sea urchin embryogenesis
Authors: Alliegro Mark C. , Black Steven D. , McClay David R. 
Published: February 2005

AbstractThe apical extracellular matrix of the sea urchin embryo, known as the hyaline layer (HL), is a multi‐laminate organelle composed of at least 10 polypeptides. Although integrated into one ECM, HL proteins exhibit individual temporal and spatial dynamics throughout development. These molecules are stockpiled in the oocyte during vitellogenesis in at least four distinct vesicle populations. They are released onto the cell surface at fertilization in a specific order, and interact differentially with embryonic cells as development proceeds. Many experiments have suggested that the HL is vital for embryogenesis, but relatively little is known about the functions and interactions of its constituent molecules. The purpose of the present review has been to gather information on the basic characteristics of the known HL proteins together with data on their expression in the embryo, and where possible, their biological activities. Compiled, these observations may provide some insight into the workings of a uniquely embryonic organelle. © 1992 Wiley‐Liss, Inc.
Cell lineage in molluscan development
Authors: Dohmen R. M. 
Published: February 2005

AbstractCell lineage specification in molluscs is brought about by two mechanisms: the segregation of morphogenetic plasms and inductive cell interactions. The evidence for the existence of morphogenetic plasms is largely circumstantial, but in one species, Bithynia, such a plasm has been identified in the polar lobe that forms at first cleavage. Inductive cell interactions are thought to be a prerequisite for the development of a large number of tissues and organs. The most extensively studied example is the specification of the mesodermal stem cell in Lymnaea and Patella, which occurs between 5th and 6th cleavage through an interaction between one macromere and a large number of micromeres.Both segregation and induction are tuned to the animal‐vegetal polarity of the egg, at least during early development. This polarity probably arises during oogenesis and is manifest in regional differentiations of the surface architecture of the egg, in the distribution of inner membrane particles in the plasma membrane, in membrane fluidity characteristics, in ionic conductance properties of the plasma membrane, etc. All these phenomena have in common that they represent properties of the egg surface, suggesting that the polarity of the egg is somehow imprinted into the plasma membrane and the cortex of the egg during oogenesis. © 1992 Wiley‐Liss, Inc.
Role of ultrastructural studies in the analysis of cell lineage in the mammalian pre‐implantation embryo
Authors: Cruz P. Y. 
Published: February 2005

AbstractUltrastructural studies have contributed significantly to our understanding of cell lineage differentiation in the mammalian pre‐implantation embryo. Such studies have documented, and continue to document, morphological, biochemical, and physiological characteristics of the cell lineages established during the pre‐implantation period in eutherian embryos, principally that of the mouse. This review evaluates these contributions and identifies areas of study in which ultrastructural analysis is most likely to have an important role in the future. © 1992 Wiley‐Liss, Inc.
Chemical extraction of the cytosol using osmium tetroxide for high resolution scanning electron microscopy
Authors: Lea P. J. , Hollenberg M. J. , Temkin R. J. , Khan P. A. 
Published: February 2005

AbstractDetailed examination of subcellular structures in three dimensions (3D) by high resolution scanning electron microscopy (HRSEM) is now possible due to improvements in the design of the scanning electron microscope and the introduction of methods of specimen preparation using chemical removal of the cytosol and cytoskeleton by dilute osmium tetroxide. Cells which have been fixed, frozen, cleaved, thawed, and subjected to cytosol extraction display intact intracellular structures in 3D including nuclear chromatin, endoplasmic reticulum, mitochondria, and the Golgi complex at a resolution close to that of conventional biological transmission electron microscopy (TEM). Small changes in the 3D structure of subcellular components can be conveniently examined in this way in development, in a variety of physiological processes and in disease. Broad areas of the specimen can be quickly surveyed by HRSEM since sectioning is not required and specimens of comparatively large size (up to 5 mm3) can be placed in the microscope. Extraction of the cytosol with dilute osmium tetroxide (OsO4) exposes subcellular structures in relief, permitting their examination in 3D from several aspects. However, the OsO4 extraction technique is limited, since significant intracellular structures, such as the cytoskeleton, vesicles, and antibody binding sites can be removed or inactivated during the cytosol removal steps. © 1992 Wiley‐Liss, Inc.
Determination of conditions for optimum resolution of a high angle thin window energy dispersive spectrometer
Authors: Blackford Mark G. , Smith Katherine L. 
Published: February 2005

AbstractThe energy resolution of an energy dispersive spectrometer (EDS) equipped with an ultrathin window (UTW) and mounted at a high take‐off angle (72°) on a transmission electron microscope has been studied under a variety of operating conditions. The spectrometer resolution is close to that specified by the manufacturer, up to count rates of 400 cps. Above 400 cps the resolution deteriorates rapidly, and the MCA dead time and zero width increase. Above 10 ke V, the height of the background is much greater than expected for bremsstrahlung and shows the shape which has previously been attributed to backscattered electron flux into the detector. It is postulated that the deterioration in resolution with count rate is caused by backscattered electrons reaching the detector through the UTW. © 1992 Wiley‐Liss, Inc.
Preparation of aqueous standards for low temperature x‐ray microanalysis
Authors: Reid A. P. , Potts W. T. W. , Oates K. , Mulvaney R. , Wolff E. W. 
Published: February 2005

AbstractA technique, using Nuclepore polycarbonate membrane filters as a containing medium for very small volumes of ionic standard solutions, to produce homogeneous ice standards is described. The standards are suitable for use in a scanning electron microscope. The relationship between elemental X‐ray counts and ionic concentration is found to be linear. The method is rapid and simple. Minimum detectable concentrations are given. © 1992 Wiley‐Liss, Inc.
Ultrastructural studies on membrane, cytoskeletal, mucous, and protective compartments in olfaction
Authors: Ph. M. Menco Bert 
Published: February 2005

AbstractThere is a great variety in the morphological appearance of olfactory structures across the metazoan animal kingdom. Despite this variety the receptive structures themselves have a strikingly similar architecture, namely some type of elongated cellular extension that is spanned by a membrane and surrounded by mucus. These cellular extensions can either be modified primary or secondary cilia, or microvilli. There are more similarities between membranes of these extensions than between the cytoskeletal elements immediately underneath the membranes. One might infer that the cytoskeletal elements of the cellular extensions merely serve as a scaffold for the membranes, whereas the similarity in membrane ultrastructure provides morphological evidence supporting the concept that these membranes are responsible for the initial olfactory transduction process. The transduced message is transported to the brain, where it is decoded to initiate the cascade of events resulting in the organisms' appropriate behavioral response to the initial odorous stimulus. The varying appearance of olfactory structures across the animal kingdom is probably produced by evolutionary pressure to adapt the olfactory system to the animal's environment. This review deals with the ultrastructural aspects of these facets of olfaction. © 1992 Wiley‐Liss, Inc.
Peripheral sensilla of some lower invertebrates: The platyhelminthes and nematoda
Authors: Wright Kenneth A. 
Published: February 2005

AbstractThe flatworms (Platyhelminthes) and the round worms (Nematoda) are phylexhibiting strikingly different levels of cellular organization. In both, sensilla are composed of the endings of sensory dendrites intercalated into their epidermis.In flatworms, sensilla that penetrate the syncytial epidermis bear sensory processes derived from cilia. In free‐living species, the sensory processes more closely resemble motile cilia, while in parasites, greater deviations occur from the classical cilium pattern. Estimates of the function of the various sensilla have been largely arbitrary, and remain based on ultrastructural features.Sensilla in round worms lie below or within a heavy secreted cuticle. Two glia‐like cell types occur. The socket cell mediates contact with cuticle and is responsible for cuticular modifications essential for operation of the sensillum. The sheath cell forms a receptor cavity around the sensory processes and regulates its environment. Sensory processes vary greatly from the classical cilium pattern. Absence of a basal body, but preservation of a ciliary necklace, suggests that the latter has a primary importance in sensory transduction. Estimates of function are based largely on ultrastructural features and analogies to arthropod sensilla. Genetic studies with the free‐living nematode Caenorhabditis are beginning to demonstrate details of function and development.Speculations on the roles of basal bodies, rootlets, and vesicles and on the significance of recessed sensilla are given. © 1992 Wiley‐Liss, Inc.
Preparation of TEM foils from Nb‐10 a/ Si
Authors: Cockeram Brian , Omlor Ralph E. , Srinivasan Raghavan , Weiss Isaac , Jackson Allen G. 
Published: February 2005

AbstractDuctile phase toughened composites contain phases with significantly different physical properties. Consequently, these phases thin at different rates depending on the sample preparation procedure. A new TEM foil preparation method for the ductile phase toughened Nb‐10 a/o Si material has been developed. The method involves chemical thinning in a 70% nitric acid/ 30% hydrofluoric acid solution followed by electropolishing in a 12.5% sulfuric acid/87.5% methanol electrolyte at −40°C. This procedure for making TEM foils results in large thin areas with the minimum of artifacts. Mechanical grinding of a sample followed by either ion milling, dimpling, or electropolishing produced foils with large electron transparent areas, but with uncharacteristic features of the original Nb‐10 a/o Si alloy microstructure. These artifacts were identified as dislocations, surface mottling, and antiphase domains. © 1992 Wiley‐Liss, Inc.
In situ freeze‐fracture of monolayer cell cultures grown on a permeable support
Authors: Todd John H. , Sens Donald A. , Sens Mary Ann , Hazen‐Martin Debra 
Published: February 2005

AbstractThe growth of cultured epithelial cells on permeable supports allows increased cell differentiation and the assessment of a variety of transcellular and paracellular transport processes. The need to assess the corresponding ultrastructural characteristics of these cells underidentical conditions prompted this laboratory to develop a reliable method for producing freezefracture replicas of these cultures. Sections of filter inserts with the cell‐side facing up are placed between layers of polyvinyl alcohol with a strip of mylar positioned on the upper layer of polyvinyl alcohol. Following freezing, the monolayer is fractured by lifting the mylar strip from the assembly. The result is a consistent fracture of the apical membrane sufficient for analysis of tight junction sealing strands, microvilli distribution, and intramembranous particle (IMP) distribution between apical and lateral membrane domains. This method utilizes standard equipment and readily available materials and, most importantly, allows the freeze‐fracture and replication of an undisturbed cell monolayer. © 1992 Wiley‐Liss, Inc.
Experimental morphology of insect olfaction: Tracer studies, x‐ray microanalysis, autoradiography, and immunocytochemistry with silkmoth antennae
Authors: Steinbrecht Rudolf Alexander 
Published: February 2005

AbstractThe general morphology and methodological peculiarities of insect sensilla are briefly reviewed. The stimulus conducting pore‐tubule systems of pheromone‐sensitive sensilla of the silkmoths Bombyx mori and Antheraea polyphemus are described. Lipophilic tracers readily enter the hair lumen, while hydrophilic tracers do so only after prolonged extraction with lipid solvents and/or pronase. X‐ray microanalysis demonstrates a high potassium content of the sensillum lymph; calcium was only found in the haemolymph above detection limit. Auxiliary cells rapidly take up radioactive leucine administered via the haemolymph. Antibodies against pheromone‐binding protein of Antheraea polyphemus label the sensillum lymph of sensilla trichodea, but not of sensilla basiconica in A. polyphemus as well as in B. mori. The cytoplasm of auxiliary cells of the sensilla trichodea is also labelled. The results are discussed in context with present hypotheses on the role of sensillum lymph in stimulus transport and inactivation. © 1992 Wiley‐Liss, Inc.
Limitations of monastral blue as a vascular label: Rapid rate of clearance is age‐dependent, and interactions with anesthetics depress arterial blood pressure in rats
Authors: Drake Wendy T. , Creighan Michael , Sims David E. 
Published: February 2005

AbstractMonastral blue (MB) has been described as an inexpensive, nontoxic vascular label. Discrepancies as to its rate of removal from circulation and physiological side effects prompted this study in which retention time of MB in the vascular system and effects of MB upon arterial blood pressure with different anesthetics (halothane, isoflurane, and pentobarbital) were measured in rats. Arterial pressure was monitored during intravenous infusion of MB with or without Evans blue, an albumin label. Localized areas of leakage were created by injecting 30 μL of 10−4 M histamine into abdominal dermis at −2, 0, 5, 7, 10, and 15 minutes from infusion of MB. Mean arterial pressure decreased by 25–30% after MB infusion when halothane or isoflurane was used, but not with pentobarbital. Sites which leaked at 10 and 15 minutes did not usefully label with MB, although Evans blue‐labelled albumin appeared in the interstitium. Younger, lighter rats (125–200 vs. 200–250 gm) retained MB longer in circulation, and had a shorter duration of MB‐induced hypotension. Spectrophotometric analysis of rat serum showed rapid elimination of MB from the vascular system, with a half‐life of 3.5 ± 1.9 minutes. While MB remains a useful vascular label, its rapid removal from the circulation and its hypotensive effect must be recognized. © 1992 Wiley‐Liss, Inc.
Accurate d‐spacings from zero‐order laue zone patterns
Authors: Le Page Y. 
Published: February 2005

AbstractExperimental d‐spacing values are criteria towards the identification of crystallites by electron diffraction. Conclusive identifications often rely on accurate d‐spacings. It is shown here that accurate orthogonal components (in mm) for the primitive unit vectors of a zero‐level diffraction pattern can be obtained through least‐squares processing of (x,y) coordinates for all spots on the film. Valid vectors hom the origin spot to any spot in the plane of the film are integer linear combinations of the two selected unit vectors. Accurate lengths and standard deviations for such vectors therefore can be calculated from the least‐squares results. Corresponding d‐spacings can then be calculated from the vector lengths on the film and the camera constant. In order to obtain d‐spacing values that are not only precise, but also accurate, an accurate value of the camera constant should be used. This requires calibration of the experimental setup with reference materials in the same experimental conditions, with careful control of the sample height. For the same quality of measurements, the improvement in the accuracy of the d‐spacings obtained with the proposed method is approximately proportional to the square root of the number of measurements taken. Practically, typical improvement in accuracy is about threefold, and accuracies of a fraction of a percent in d‐spacings are achievable in this way. The above approach has been programmed as an option in the NRCBED program. © 1992 Wiley‐Liss, Inc.