bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of cell death and cell proliferation in embryonic stages, normal adult, and aging prostates in human and animals
Authors: Sensibar Julia A. 
Published: February 2005

AbstractHomeostasis in the prostate is recognized to be maintained by a complex interplay between the opposing actions of cell proliferation and Cell death. Growth regulatory factors that promote or inhibit cell proliferation and promote cellular death have been identified in the prostate. The integration of these forces involves cellular cooperation between the prostatic stroma and epithelium. Hormone‐regulated production of growth regulatory factors by one cell type may determine growth stimulation, inhibition, or cell death in a reciprocal cell partner. Imbalance between net cell proliferation and net cell death rates may result in abnormal growth leading to BPH. Additional study of the growth regulatory factors associated with distal vs. proximal epithelial cells and stroma and comparison of growth factor expression by the neonatal, postnatal growing, adult quiescent, and aging prostates will likely provide further insight into the regulation of prostate cell division and death. © 1995 Wiley‐Liss, Inc.
Muscle‐specific gene expression during myogensis in the mouse
Authors: Ontell Marcia , Ontell Martin P. , Buckingham Margaret 
Published: February 2005

AbstractOver the past decade, significant advances in molecular biological techniques have substantially increased our understanding of in vivo myogenesis, supplementing the information that previously had been obtained from classical embryological and morphological studies of muscle development. In this review, we have attempted to correlate morphogenetic events in developing murine muscle with the expression of genes encoding the MyoD family of myogenic regulatory factors and the contractile proteins. Differences in the pattern of expression of these genes in murine myotomal and limb muscle are discussed in the context of muscle cell lineage and environmetal factors. The differences in gene expression in these two types of muscle suggest that no single coordinated pattern of gene activation is required during the initial formation of the muscles of the mouse. © 1995 Wiley‐Liss, Inc.
Expression of myosin heavy chain isoforms and myogenesis of intrafusal fibres in rat muscle spindles
Authors: Soukup Tomáš , Pedrosa‐Domellöf Fatima , Thornell Lars‐Eric 
Published: February 2005

AbstractThis review concerns the pattern of expression and regulation of myosin heavy chain (MHC) isoforms in intrafusal fibres of rat muscle spindles detected by immunocytochemistry. The three types of intrafusal fibres—nuclear bag1, nuclear bag2, and nuclear chain fibres—are unique in co‐expressing several MHCs including special isoforms such as slow tonic and α cardiac‐like MHC and isoforms typical of muscle development, such as embryonic and neonatal MHC. The distinct intrafusal fibre types appear sequentially during rat hind limb development, the nuclear bag2 precursors being first identifiable at 17–18 days in utero as the only primary myotubes expressing slow tonic MHC. Sensory innervation is required for the expression of “spindle‐specific” MHC isoforms. Motor innervation contributes to the diversity in distribution of the different MHCs along the length of the nuclear bag fibres. It is suggested that unique populations of myoblasts are destined to become intrafusal fibres during development in the rat hind limb muscles and that the regional heterogeneity in MHC expression is related both to sensory and motor innervation and to the properties of the myoblast lineages. These distinct features make intrafusal fibres an attractive in situ model for investigating myogenesis, myofibrillogenesis, and the mechanisms regulating MHC expression. © 1995 Wiley‐Liss, Inc.
Postembedding colloidal‐gold immunocytochemistry of noncollagenous extracellular matrix proteins in mineralized tissues
Authors: McKee M. D. , Nanci A. 
Published: February 2005

AbstractImmunocytochemistry is a powerful tool for investigating protein secretion, extracellular matrix assembly, and cell‐matrix and matrix‐matrix/mineral relationships. When applied to the tissues of bones (bone and calcified cartilage) and teeth (dentin, cementum, and enamel), where calcium phosphate–containing extracellular matrices are the predominant structural component related to their weight‐bearing and masticatory roles, respectively, data from immunocytochemical studies have been prominent in advancing our understanding of mineralized tissue modeling and remodeling. The present review on the application of postembedding, colloidal‐gold immunocytochemistry to mineralized tissues focuses on the advantages of this approach and relates them to conceptual, theoretical, and experimental data currently available discussing matrix‐mineral interactions and extracellular matrix formation and turnover in these tissues. More specifically, data are summarized regarding the distribution and role of noncollagenous proteins in different mineralized tissues, particularly in the context of how they interface with mineral, and how this relationship might be affected by the various tissue‐processing steps and immunocytochemical strategies commonly implemented to examine the distribution and function of tissue proteins. Furthermore, a technical discussion is presented that outlines several different possibilities for epitope exposure in mineralized tissues during preparation of thin sections for transmission electron microscopy. Cell biological concepts of protein secretion by cells of the mineralized tissues, and subsequent extracellular matrix assembly and organization, are illustrated by examples of high‐resolution, colloidal‐gold immunolabeling for osteopontin, bone sialoprotein, and osteocalcin in the collagen‐based mineralized tissues and for enamel protein (amelogenin) in enamel. © 1995 Wiley‐Liss, Inc.
Immunocytochemistry of the muscle cell cytoskeleton
Authors: Stromer Marvin H. 
Published: February 2005

AbstractThe muscle cell cytoskeleton is defined for this review as any structure or protein primarily involved in linking or connecting protein filaments to each other or to anchoring sites. In striated muscle, the M line connects thick filaments at their centers to adjacent thick filaments. Titin forms elastic filaments that extend from the M line to the Z line and may contribute to the resting tension properties of striated muscle. Nebulin forms inextensible filaments in skeletal muscle that are closely associated with thin filaments and that may provide a length template for thin filaments. Z lines anchor thin filaments from adjacent sarcomeres via the actin‐binding function of α‐actinin. Other proteins located at the Z line include Cap Z, Z‐nin, Z protein, and zeugmatin. Intermediate filaments connect myofibrils to each other at the level of the Z line and to the sarcolemma at the Z‐ and possibly the M‐line levels. Immunolocalization has identified the adhesion plaque proteins spectrin, vinculin, dystrophin, ankyrin, and talin at subsarcolemmal sites where they may be involved with filament attachment. Smooth muscle cell cytoskeletons are believed to include membrane associated dense bodies (MADBs), intermediate filaments, cytoplasmic dense bodies (CDBs), and perhaps a subset of actin filaments. MADBs contain a menu of attachment plaque proteins and anchor both thin filaments and intermediate filaments to the sarcolemma. CDBs are intracellular analogs of striated muscle Z lines and anchor thin filaments and intermediate filaments. © 1995 Wiley‐Liss, Inc.
Uranium‐contaminated soils: Ultramicrotomy and electron beam analysis
Authors: Buck Edgar C. , Dietz Nancy L. , Bates John K. 
Published: February 2005

AbstractUranium‐contaminated soils from the U.S. Department of Energy (DOE) Fernald Site, Ohio, have been examined by a combination of backscattered electron imaging (BSE) and analytical electron microscopy with electron diffraction (AEM). The inhomogeneous distribution of particulate uranium phases in the soil required the development of a method for using ultramicrotomy to prepare transmission electron microscopy (TEM) thin sections from the SEM mounts. A water‐miscible resin was selected that allowed comparison between SEM and TEM images, permitting representative sampling of the soil. Uranium was found in iron oxides, silicates (soddyite), phosphates (autunites), and uraninite (UO2+x). No uranium was detected in association with phyllosilicates in the soil. © 1995 Wiley‐Liss, Inc.
Em‐tomography of section collapse, a non‐linear phenomenon
Authors: van Marle J. , Dietrich A. , Jonges K. , Jonges R. , de Moor E. , Vink A. , Boon P. , van Veen H. 
Published: February 2005

AbstractUsing back projection for reconstruction and tilt series of Epon or Lowicryl embedded and sectioned material, we demonstrated: (1) a reduction in thickness of 50% for Epon and 80% for Lowicryl sections, and (2) a non‐uniform density distribution along the electron‐optical axis in sections. The highest density was found at the vacuum exposed side of the section. The formvar side of the section showed a similar increase in density, but not to the same extent. Minimalization of electron exposure, even without pre‐exposure, did not affect the reconstructed thickness, nor did it affect the non‐uniform density distribution. However, parallax measurements showed that at 150K, collapse of Epon sections does not take place. For EM‐tomography of plastic embedded material our findings imply that at the top and bottom portion of the sections the dimensions of the reconstructed structures are distorted, but that in the middle portion the dimensions are reliably retained. © 1995 Wiley‐Liss, Inc.
Comparative methodological investigations on the cytochemical localization of calcium in brain and inner ear of cichlid fish
Authors: Vöhringer Petra , Nindl Gabi , Aich Brigitta , Körtje Karl‐Heinz , Rahmann Hinrich 
Published: February 2005

AbstractFour different methods for calcium precipitation are compared in the optic tectum and the inner ear of the cichlid fish, Oreochromis mossambicus. Several parameters are investigated concerning their influences on the reaction product. Three procedures (bichromate, fluoride, and oxalate‐pyroantimonate) produce fine‐grained deposits, often flocculent in the latter method. The fourth method (potassium‐pyroantimonate) generates predominantly coarse‐grained reaction product. The calcium content of the deposits is always proven with energy‐filtering transmission electron microscopy (EFTEM). In both tissues fine‐grained reaction product is found in endoplasmic reticulum and synaptic vesicles, and in addition in some mitochondria and at the cytoskeleton. The coarse‐grained deposits of the potassium‐pyroantimonate method have a more unspecific distribution. This is the only method which produces extracellular deposits in the inner ear, whereas in the optic tectum extracellular precipitates are always present except with the oxalate‐pyroantimonate procedure. Two factors have an influence on the reaction product: the duration of fixation and the type of resin. The prolongation of the fixation time up to 24 hours leads to an increase of the reaction product, which also becomes coarse‐grained. These observations are corroborated by quantification with image analysis. Furthermore the use of an epoxy resin compared to acrylic resins decreases the amount of reaction product produced. We show that the application of several methods is meaningful in order to understand the calcium properties of the investigated tissue, but it is necessary to optimize a certain method for a given tissue. © 1995 Wiley‐Liss, Inc.
Ocular lens gap junctions: Protein expression, assembly, and structure‐function analysis
Authors: Kistler Joerg , Evans Clive , Donaldson Paul , Bullivant Stanley , Bond Jacqui , Eastwood Sharon , Roos Marc , Dong Yimin , Gruijters Terry , Engel Andreas 
Published: February 2005

AbstractRecent advances in understanding lens fiber gap junction formation are reviewed. These include studies of junctional protein expression in the embryonic lens, and of age related changes affecting gap junction structure and composition in the adult lens. An in vitro assembly system based on detergent solubilized pore complexes and endogenous lipids has been developed to provide information on the molecular interactions involved in gap junction formation and to provide material for structure analysis. Important information on the electrical properties of lens gap junction channels is obtained using electrophysiological techniques including planar lipid bilayer analysis and patch clamping. © 1995 Wiley‐Liss, Inc.
Structural and molecular determinants of intercellular coupling in cardiac myocytes
Authors: Lee Kanter H. , Beyer Eric C. , Saffitz Jeffrey E. 
Published: February 2005

AbstractElectrical activation of the heart requires intercellular transfer of current through gap junctions connecting individual cardiac myocytes. Using a combination of light and electron microscopic techniques and molecular approaches, we have characterized the number, size, and spatial distribution of intercellular connections at gap junctions in cardiac myocytes and have also cloned, sequenced, and elucidated the subcellular distribution of three physiologically distinct gap junction channel proteins. In this review, we present evidence to suggest that the spatial distribution of myocyte interconnections and the molecular composition of gap junction channels may confer distinct conduction properties on specific tissues of the mammalian heart such as atrial and ventricular myocardium, and the nodes and bundles of the cardiac conduction system. © 1995 Wiley‐Liss, Inc.
Role of gap junctions in the development of the preimplantation mouse embryo
Authors: Becker David L. , Davies Catherine S. 
Published: February 2005

AbstractWe have taken several approaches to study the role of gap junctional communication during preimplantation mouse development. Firstly, the normal expression pattern of gap junctions has been characterized using immunostaining in conjunction with laser scanning confocal microscopy. Changes in junctional distribution have been correlated with developmental events. We have gone on to study development and junctional organization in mice which naturally exhibit reduced cell to cell communication (DDK syndrome), and in normal mice in which gap junction permeability has been artificially manipulated. Furthermore, anti‐peptide antibodies hae been tested for their ability to block gap junction communication and for the effects of such a block on subsequent development. Collectively, the results demonstrate that gap junctional communication plays an important role in the maintenance of compaction and the differentiation of an organized epithelium within an embryo, features which are vital for preimplantation development to progress successfully. © 1995 Wiley‐Liss, Inc.
Quantitative junctional permeability measurements using the confocal microscope
Authors: Miller Lan 
Published: February 2005

AbstractThis paper describes the use of a photobleach method and confocal microscopy to compare the cell‐to‐cell transfer rate of 5,6 carboxyfluorescein in dissociated embryonic chick lens cells with those in the anterior epithelium of the whole embryonic chick lens. The average cell‐to‐cell transfer rates obtained were 7.9 × 10−3 sec−1 in the dissociated cells and 2.6 × 10−3 sec−1 in the anterior epithelium in an intact lens. © 1995 Wiley‐Liss, Inc.
Lectin binding and identification of sialic acid acceptor sugars in rabbit oviduct under hormone administration
Authors: Menghi Giovanna , Scocco Paola , Materazzi Giovanni 
Published: February 2005

AbstractLocalization of individual glycosidic residues and sialic acid acceptor sugars was investigated by conjugated lectins in the rabbit oviduct under physiological hormonal conditions and human chorionic gonadotropin (HCG) administration. Ampulla and isthmus were found to exhibit lectin binding profiles typical of each hormonal stage. Two different sialylated glycomolecules were identified within the epithelial lining; in particular, sialoglycoconjugates characterized by the terminal sequence sialic acid‐galactose were visualized in the secretory cells and the sialic acid‐N‐acetylgalactosamine terminal disaccharides were localized on both ciliated and secretory cells of the entire oviduct. Surface and cytoplasmic sialoglycoconjugates were also found to exhibit a differential behaviour inside the two oviduct tracts examined. Present findings further supported the idea that in ampulla and isthmus, the greatest modifications consequent to hormone treatment take place at different times. © 1995 Wiley‐Liss, Inc.
Morphology and physiological significance of parathyroid glands in reptilia
Authors: Srivastav Ajai Kumar , Sasayama Yuichi , Suzuki Nobuo 
Published: February 2005

AbstractAdult reptiles possess one or two pairs of parathyroid glands that have been shown in many species to derive from the third and fourth pharyngeal pouches, respectively. Up to five pairs may develop during early embryonic life. Excess glands may involute during late embryogenesis. The location of the parathyroid glands differs in the various species. As a general rule, they lie just anterior to the heart, the anterior pair (parathyroid III) being associated with the carotid artery, the posterior pair (parathyroid IV) with the aortic arch. In snakes, however, the anterior pair (parathyroid III) is associated with the carotid artery near the angle of the jaw. As shown by light microscopy and, to a lesser extent, by electron microscopy, the parathyroid parenchyma comprises secretory cells which may form dark and light variants, occasional oxyphil cells, and stellate cells. They are arrangend in cords separated by connective tissue containing a capillary network. Parathyroid secretory cells often form follicles which might be the result of degeneration. Degeneration may occur as a form of involution during winter in species undergoing seasonal changes. The product of parathyroid cells, the parathyroid hormone, is responsible for the maintenance of blood calcium concentration. The sites of action—bones, kidneys, intestine, endolymphatics, and dermal skeleton—are not well understood or not investigated. In some turtles, parathyroid hormone is not the (main) factor for the regulation of calcium homeostasis. © 1995 Wiley‐Liss, Inc.
Blood vascular bed and pericapillary space in rat parathyroid glands
Authors: Murakami Takuro , Tanaka Toshihisa , Taguchi Takehito , Ohtsuka Aiji , Kikuta Akio 
Published: February 2005

AbstractThe blood vascular bed and pericapillary space of the rat parathyroid gland were studied by scanning electron microscopy of vascular casts, freeze‐cracked tissue blocks, and NaOH‐treated tissue specimens. The findings were supplemented by transmission light and electron microscopy of sectioned tissue samples. The rat parathyroid gland contained a rich network of freely anastomosing capillaries. These capillaries were surrounded by marked pericapillary spaces that were demarcated by basal lamina of both capillaries and parenchymal cells. The pericapillary spaces contained many collagen fibrils and frequently issued some projections running deep into the sheets of parathyroid cells. The latter projections may be useful to supply the parenchymal cells located far from the capillaries. The collagen fibrils may regulate the flow of tissue fluid in the pericapillary space and convey parathyroid hormone, which is released at the apicolateral domain, into the capillaries. © 1995 Wiley‐Liss, Inc.
The biological significance of storage granules in rat parathyroid cells
Authors: Setoguti T. , Inoue Y. , Wild P. 
Published: February 2005

AbstractBoth prosecretory and storage granules are concomitantly formed at the trans Golgi network including the innermost Golgi cisterna. Prosecretory granules develop into small secretory granules that release their contents by exocytosis finely regulated by a complex mechanism for maintaining calcium homeostasis. In the rat parathyroid cells, storage granules are large secretory granules storing parathyroid hormone for an emergency supply. The hormone is rapidly discharged by exocytosis when serum calcium concentration is decreased. The granules are constantly produced even under conditions of low serum calcium concentration in the regions of 8 mg/dl. The granule content is constantly hydrolyzed when not discharged, leading to a decreased core and finally to the formation of vacuolar bodies. The fate of the vacuolar bodies is unknown. Hypercalcemic conditions accelerate hydrolysis. The threshold value of calcium concentration required for the release of storage granule contents is between 8.0 and 7.5 mg/dl and that of calcium concentration for accelerating degradation of storage granules is about 11.5 mg/dl. Sympathetic stimulation causes storage granules to be discharged regardless of hypercalcemia or hypocalcemia. Parasympathetic stimulation accelerates hydrolysis. The degradation of storage granules seems to be closely associated with an intracellular regulatory mechanism for parathyroid hormone secretion. © 1995 Wiley‐Liss, Inc.
Murine model of genetic demyelinating disease: The twitcher mouse
Authors: Suzuki Kinuko , Taniike Masako 
Published: February 2005

AbstractTwitcher mouse is an authentic murine model of human genetic demyelinating disease, globoid cell leukodystrophy (GLD), or Krabbe disease. Since its discovery at the Jackson Laboratory (Bar Harbor, ME) this model has been used extensively for the morphological, biochemical‐enzymatic studies to clarify pathogenesis and also for therapeutic manipulation of genetic demyelinating disease in humans. As a result of these studies, now we know that (1) GLD is caused by a deficiency of lysosomal enzyme galactosylceramidase, and a toxic metabolite, psychosine, accumulates in the tissue, including the nervous system, damaging myelin forming cells and resulting in secondary demyelination; (2) morphological features of demyelination and associated cellular reactions in demyelination in this mutant are similar to those seen in autoimmune or toxic demyelination; and (3) with enzyme supplementation provided by bone marrow transplantation, remyelination occurs to some extent in demyelinated fibers in both central and peripheral nervous systems of twitcher mouse. © 1995 Wiley‐Liss, Inc.
Comparison of different drying procedures for scanning electron microscopy using human leukocytes
Authors: Ting‐Beall H. Ping , Zhelev Doncho V. , Hochmuth Robert M. 
Published: February 2005

AbstractUsing human leukocytes as test specimens, three different drying procedures for scanning electron microscopy: critical‐point drying (CPD), Peldri II, and tetramethylsilane (TMS), were compared. All three procedures produced identical surface morphology preservation. An equal amount of volume shrinkage was observed regardless of the dehydrants and drying techniques employed. Considering the simplicity, convenience, and time saved, air‐drying with TMS is by far the best choice for preparing animal cells for scanning electron microscopy. © 1995 Wiley‐Liss, Inc.