bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphological types of neurons located at taste‐responsive sites in the solitary nucleus of the hamster
Authors: Whitehead Mark C. , McPheeters Martha , Savoy Larry D. , Frank Marion E. 
Published: February 2005

AbstractHRP histochemistry and microelectrode mapping were combined to study the sizes, shapes, and orientations of neuronal cell bodies and dendrites located at sites of taste‐elicited single unit activity in the nucleus of the solitary tract (NST). Cells responding to sapid stimulation of the anterior tongue were extracellularly recorded using micropipettes containing HRP. Iontophoretic injection of the marker at the recording sites resulted in small (50–200 μm diameter) opaque zones bordered by a small number (2–15) of neurons with Golgi‐like filling of their cell bodies, dendrites, and to some extent, their axons. The cell bodies were near (50–250 μm) the injection sites into which they sent labelled dendrites. Two broad categories of neurons were typically filled. Elongate cells had oval‐ to spindle‐shaped cell bodies oriented mediolaterally. Two primary dendrites extended 100–300 μm from the cell body, one medially and one laterally, and branched within a cylindrical dendritic field oriented mediolaterally. A minority of the HRP‐filled elongate cells had unusually long rostrally or caudally directed dendritic branches. Stellate cells had oval, round, triangular, or polygonal cell bodies and 3–5 primary dendrites coursing 200–300 μm in all directions and branching as unoriented, spheroidal fields. A minority of stellate cells had relatively unbranched wavy dendrites, resembling tentacles, while others had unusually small cell bodies (10–15 μm diameter), small dendrites, and locally arborizing axons. Of 151 labelled cells, all but 12 were remarkably confined to the rostral NST. Nearly 90% were concentrated in the rostral central cytoarchitectonic subdivision, where stellate cells predominated, or in the rostral lateral subdivision, where elongate cells predominated. These morphological types of neurons, filled at neurophysiological recording sites, are compared with cell types identified in previous light and electron microscopic studies of the cytoarchitecture, connections, and synaptic organization of the gustatory NST. © 1993 Wiley‐Liss, Inc.
Interaction of lung surfactant protein a with alveolar macrophages
Authors: Ohmer‐Schröck Daniela , Schlatterer Christina , Plattner Helmut , Schlepper‐Schäfer Jutta 
Published: February 2005

AbstractWe analyzed the binding mechanism of human recombinant lung surfactant protein A (SP‐A) to rat alveolar macrophages using anti‐SP‐A antiserum and protein A coated onto gold particles. Results were compared with our recent data on binding and uptake of SP‐A‐coated colloidal gold particles. The rationale for the current approach was to avoid any possible steric effects on SP‐A binding to the cell surface. Binding of unlabeled SP‐A depends on the presence of calcium ions in the medium and involves a mannose‐specific mechanism. Binding is partly inhibited by the collagenase‐resistent fragment of SP‐A, representing mainly the globular part of SP‐A. Taken together, these facts indicate binding of SP‐A via the carbohydrate binding site on the globular region of SP‐A. On the other hand, a partial inhibition of SP‐A binding by fragments of C1q (representing the collagenous region of C1q) indicates a second binding site for SP‐A by the collagen‐like portion to the C1q receptor of macrophages. We conclude that two different mechanisms are probably involved in SP‐A binding to alveolar macrophages. Specificity of the binding was shown with fluorescein‐labeled SP‐A. Binding was inhibited by an excess of unlabeled SP‐A. Binding and uptake of SP‐A are seen only with alveolar macrophages and not with other macrophage populations isolated from rat, such as liver macrophages (Kupffer cells), resident peritoneal macrophages, and peritoneal macrophages activated by Corynebacterium parvum. Therefore, binding sites for SP‐A occur exclusively on alveolar macrophages. In addition, the intracellular Ca2+ concentration of the lung macrophages was determined by using the fluorescent dye fura‐2/AM. Intracellular [Ca2+] increased immediately after addition of SP‐A. This indicates immediate activation of macrophages by SP‐A. © 1993 Wiley‐Liss, Inc.
A novel cell culture technique for electron microscopy
Authors: Wang Fen , Ledford Lindsay B. , Head Jonathan F. , Elliott Robert L. 
Published: February 2005

AbstractA simplified technique for the monolayer growth of cultured cells and their in situ embedment on the inner surface of the pyramidal portion of the Beem capsule for electron microscopy has been developed. The results demonstrated that the cell monolayers grew well on the surface of the Beem capsule and could be embedded in situ. Electron micrographs showed cells in their natural state of contact with one another. The plasma membrane and intracellular organelles were well preserved. This method minimizes many difficult steps and eliminates the disruption of cells by scraping, pelleting, or enzymatic reaction to remove them. © 1993 Wiley‐Liss, Inc.
Morphological effects of diabetes on the granular ducts and acini of the rat submandibular gland
Authors: Anderson Leigh C. , Suleiman Ahmed H. , Garrett John R. 
Published: February 2005

AbstractEffects of experimental diabetes on rat submandibular glands have been documented, but earlier reports suggested that diabetes caused an extensive cellular degeneration and a replacement of the parenchymal cells by fibrous connective tissue. Such observations, however, are difficult to reconcile with the relatively normal physiological responsiveness of the gland (Anderson and Suleiman, 1989). This study, therefore, reexamined the histological, histochemical and ultrastructural effects of streptozotocin‐induced diabetes on rat submandibular glands. The tissues were examined at 3 weeks, and 3 and 6 months after the induction of diabetes, and compared with glands from age‐matched controls by both light and electron microscopy. Light microscopically, the proportional volumes of the acini and granular ducts remained constant in control rats at about 48% and 38% respectively. In diabetic animals the volume density of the acini increased progressively to 62%, whereas that of the granular ducts decreased to 20%. The diameter and number of granular ducts were reduced in diabetic animals, but acinar cell profile area was only affected 6 months after the induction of diabetes. Ultrastructurally, there was an accumulation of lipid in the acinar cells and, with increasing duration of diabetes, the number of autophagic structures in both the acini and the granular ducts increased. Although there was evidence of some cellular degeneration it was never excessive. Morphometry showed that the volume density of secretory granules within the acinar cells was unaffected, but there was a significant reduction in the volume density of secretory granules within the granular ducts. Thus, in the rat submandibular gland the greatest effect of streptozotocin‐induced diabetes was to cause hypotrophic changes in the cells of the granular ducts. The relative contributions of a direct effect of insulin insufficiency and the hypogonadal effects of diabetes, however, are not known. © 1994 Wiley‐Liss, Inc.
Regulation of ovarian follicular development: A review of microscopic studies
Authors: Roy Shyamal K. 
Published: February 2005

AbstractFollicular development in the mammalian ovary is a complex process regulated by an orchestrated action of the pituitary gonadotropins, e.g., follicle stimulating hormone (FSH) and luteinizing hormone (LH), and local ovarian factors, such as peptide growth factors and steroids. The mechanism of endocrine/paracrine/autocrine regulation of folliculogenesis (i.e., cell proliferation and functions) has been addressed largely by biochemical means. However, the availability of immunological and molecular tools now enables us to undertake critical microscopic studies revealing the ovarian cell‐type specific synthesis and/or accumulation of many of these local peptide modulators, their roles in the proliferation and differentiation of follicular cells, and their regulation by gonadotropins and local factors. The objective of this review is to provide a comprehensive yet complete picture of the endocrine/autocrine regulation of mammalian folliculogenesis as revealed by microscopic studies. Efforts have been made to include adequate research information relevant to update our understanding of the process of follicular development; however, to maintain the brevity, many equally important studies could not be included. This review confirms that FSH and LH are still the primary stimuli for follicular development. However, it is clear that the actions of these hormones at the cell level involve a host of peptide factors which are produced locally by different follicular cell types and which are powerful modulators of gonadotropin actions. The temporal and spatial expression of the genes of these modulators, the synthesis of active factors, their interactions, and the dynamics of their receptors on the follicular cell surface may be the ultimate determinants of cellular events which are crucial to coordinated growth and differentiation of follicular cells leading to folliculogenesis and ovulation. © 1994 Wiley‐Liss, Inc.
Cytogenetic, cellular, and developmental consequences of cryopreservation of immature and mature mouse and human oocytes
Authors: Van Blerkom Jonathan , Davis Patrick W. 
Published: February 2005

AbstractThis study examined the effects of cryopreservation on cellular organization, chromosomal complement, and developmental potential of immature and mature mouse and human oocytes. Chromosomal analyses were performed by DNA fluorescence microscopy and karyotyping on the same metaphase II‐stage oocytes before and after freezing. Cellular analyses involved electron microscopy, time‐lapse video recording, and fluorescent‐probe microscopy of cortical granules. The findings demonstrate that while profound cytoplasmic, nuclear, and nucleolar alterations occur in the immature oocyte during cryopreservation, an apparently normal nucleus and cytoplasm is re‐established progressively after thawing and culture. The resulting oocytes mature at high frequency and for the mouse, are fertilizable and capable of normal preimplantation of embryogenesis. Cryopreservation of mature mouse and human oocytes is not accompanied by a significant increase in the frequency of aneuploidy. However, cryopreserved human oocytes, while fertilizable, arrest development during the early cleavage stages and display aberrant patterns of cytokinesis. The possible etiologies of developmental failure in the human embryo that may be related to oocyte cryopreservation, as well as the potential benefits of cryopreservation of the immature oocyte, are discussed with respect to clinical and commercial applications. © 1994 Wiley‐Liss, Inc.
Mitochondrial matrix granules: Their behavior during changing metabolic situations and their relationship to contact sites between inner and outer mitochondrial membranes
Authors: Jacob Wim A. , Bakker Annette , Hertsens Robert C. , Biermans Walter 
Published: February 2005

AbstractSince their discovery in the early fifties mitochondrial granules have been the subject of many researches. Some twenty years ago two hypotheses on their function were introduced. Peachey thought that the granules were a sink of cations and that they would eventually regulate the concentrations of these ions. Alternatively, Barnard thought that the granules were precursors of the mitochondrial inner membrane. There are only a few data on organic constituents of the granules. Phospholipids (e.g., cardiolipin) glycoprotein or lipids, calcium precipitable lipoprotein, cytochrome c oxidase seem to be present in the granules. There has been much debate on whether calcium is present or not. Reports are mostly based on X‐ray microanalysis, the result of which depends on preparation techniques.In heart muscle in stimulating situations the NMG (native matrix granules) move towards the inner membrane and are incorporated in it. They appear to create contact sites between inner and outer mitochondrial membranes in which enzymes can function efficiently.It is hypothetized that the system, NMG‐contact sites, forms the structural basis of a regulatory mechanism, by which cells can cope with a high and sudden energy demand. © 1994 Wiley‐Liss, Inc.
Normal and abnormal development of the blood‐brain barrier
Authors: Farrell Catherine L. , Risau Werner 
Published: February 2005

AbstractThe blood‐brain barrier is responsible for the maintenance of the neuronal microenvironment. This is accomplished by isolation of the brain from the blood by the tight junctions that join endothelial cells in cerebral microvessels, and by selective transport and metabolism of substances from blood or brain by the endothelial cells. This review describes the growth and maturation of the brain vasculature, and the development of the special properties of the endothelia at the blood‐brain interface. Evidence suggests that the development of the unique properties of the brain microvasculature is a consequence of tissue‐specific interactions between endothelial cells of extraneural origin and developing brain cells. The cellular and molecular mechanisms that control these processes are as yet unknown but this review will include experimental studies which have used in vivo and in vitro systems to investigate what factors may be involved, and some pathological conditions in which abnormal barrier development is thought to be an important aspect of the disease process. © 1994 Wiley‐Liss, Inc.
Use of fluorescent europium chelates as labels in microscopy allows glutaraldehyde fixation and permanent mounting and leads to reduced autofluorescence and good long‐term stability
Authors: Sevéus Lahja , Väisälä Mikko , Hemmilä Ilkka , Kojola Hannu , Roomans Godfried M. , Soini Erkki 
Published: February 2005

AbstractIn the present study europium chelates were introduced as alternative fluorescent labels for microscopy and their effect on enhanced autofluorescence caused by the glutaraldehyde fixative was investigated. Glutaraldehyde fixation was used to stabilize the cells for a permanent mount after the immunocytochemical reaction. The europium signal in time‐resolved fluorescence microscopy was shown to be free of autofluorescence when strong cross‐linking fixation with glutaraldehyde was used and the signal‐to‐background ratio obtained was 2,400 or better. It was also shown that the europium signal was stable in daylight and at room temperature. Fluorescent europium chelate used in this experiment provides excellent contrast and long‐term stability for the samples with glutaraldehyde fixation and permanent mounting. © 1994 Wiley‐Liss, Inc.
Comparative study of freeze‐substitution techniques for x‐ray microanalysis of biological tissue
Authors: Påsgård Eva , Lindh Ulf , Roomans Godfried M. 
Published: February 2005

AbstractA comparative study of some aspects of freeze‐substitution as a preparative method for X‐ray microanalysis of diffusible ions in biological specimens was carried out. Four substitution fluids were compared with each other and with cryosections. As criteria, elemental ratios as determined by X‐ray microanalysis of thin sections of mouse pancreas were used. Freeze‐substitution for 3 weeks in diethy ether or for 2 days in tetrahydrofurane gave results comparable to those obtained in cryosections. Slow warming to room temperature after freeze‐substitution in tetrahydrofurane gave slightly better results than fast warming. Freeze‐substitution in acetone resulted in noticeable loss and redistribution of ions and freeze‐substitution in methanol gave very poor results. © 1994 Wiley‐Liss, Inc.
Cytoskeleton of cartilage cells
Authors: Benjamin M. , Archer C. W. , Ralphs J. R. 
Published: February 2005

AbstractThe cytoskeleton of chondrocytes consists of microfilaments made of actin, microtubules made of tubulin, and intermediate filaments made of a variety of subunits. Actin filaments are not prominent in vivo but may form in vitro. In culture, changes in filament polymerisation are important in determining cell shape, initiating chondrogenesis, and maintaining the chondrogenic phenotype. Microtubules, besides their role in cell division, organise the distribution of organelles and are involved in secretory transport mechanisms in collagen and proteoglycan synthesis. A variety of intermediate filaments may be present, frequently forming large whorled aggregates. The filaments include vimentin, cytokeratins, and glial fibrillary acidic protein. These may occur at different depths in articular cartilage. Vimentin accumulates during development of some fibrocartilages with increased mechanical loading. Together with other elements of the cytoskeleton, intermediate filaments could form part of a mechanotransduction system by which cells respond to external forces and sense changes in their external environment. © 1994 Wiley‐Liss, Inc.
Automated image analyzing system for the quantitative study of living cells in culture
Authors: van Opstal W. Y. Xu‐ , Ranger C. , Lejeune O. , Forgez P. , Boudin H. , Bisconte J. C. , Rostene W. 
Published: February 2005

AbstractA fully automated image analyzing system was developed for the quantitative study of cells in culture. It was able to count cells, to classify cells according to their morphological characteristics and to follow cell culture development. A specific procedure was designed to process Hoffman modulation contrast images. It detects local gray level differences while using conditional dilation techniques. We were able to successfully detect aggregated unstained cells, presently a technical limit in image segmentation. Living cells can be studied in a noninvasive and nondestructive way with this system. An improved automatic focusing algorithm was developed which ensured an accurate prediction of the optimal focus position. A strictly defined sampling procedure was applied to estimate unbiasedly cell density and obtain precisely cell contours. The evaluation of the system was carried out on Chinese hamster ovary (CHO‐NTR) cell cultures treated with a newly developed neurotensin agonist JMV449. Chinese hamster ovary cell division was found to be retarded 20 hours after the JMV449 treatment, while the morphology of CHO‐NTR cells has already undergone significant changes 12 hours after the treatment. This image analyzing system provides the possibility to follow cell culture development (e.g., cell density evolution, cell morphological changes) under various experimental conditions. © 1994 Wiley‐Liss, Inc.
Analysis of the mechanism for acetylcholine release at the synapse formed between rat sympathetic neurons in culture
Authors: Mochida Sumiko , Nonomura Yoshiaki , Kobayashi Haruo 
Published: February 2005

AbstractSuperior cervical ganglion neurons (SCGNs) were isolated from 7‐day‐old rat SCG and cultured in MEM containing horse serum, fetal calf serum, and nerve growth factor. In this culture condition, it is well known that the SCGNs form cholinergic synapse. In 3–4 weeks cultured neurons, immunofluorescent staining for synaptophysin, a small synaptic vesicle associated protein, showed the presence of synaptophysin as small dots on the surface of the soma. Postsynaptic potentials could be recorded in 50–80% of the neurons responding to evoked action potentials elicited in neighboring neurons. Because of its relatively large cell size and the short distance to the terminal, this synapse is a useful model for studying the mechanisms of acetylcholine (ACh) release by introducing substances such as antibodies or selective inhibitors into the presynaptic neuron by means of the whole‐cell clamp technique.In this model synapse we tested the possible role of myosin in ACh release. The distribution of myosin was studied by the immunofluorescent staining technique. Myosin was recognized by the anti‐myosin II IgG at the same synaptic terminals that showed the presence of synaptophysin with its antibody. The functional blockade of myosin by the antibody itself, and that of myosin light chain kinase (MLCK) by a pseudosubstrate inhibitor of MLCK, SM‐1, or by a selective inhibitor of MLCK, wortmannin, induced depression of synaptic transmission in a dose‐dependent manner. These indicate that phosphorylation of myosin by MLCK may be necessary for ACh release mechanisms. © 1994 Wiley‐Liss, Inc.
Classification of the enteric nerve cells of the porcine small intestine into two subpopulations using enzyme histochemical techniques
Authors: De Ridder E. , Weyns A. 
Published: February 2005

AbstractUsing acetylcholinesterase (AChE), nicotinamide adenine dinucleotide diaphorase (NADHd), and nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) enzyme histochemical techniques, the ganglionated plexuses of the porcine enteric nervous system were investigated in small intestine whole‐mount preparations. Both AchE and NADHd techniques revealed a majority of the neurons in the ganglia of all three major plexuses. The AchE technique also demonstrated clearly the axodendritic networks of the plexus myentericus. Intraganglionic blank areas revealed the localization of negative cell groups. A very high correlation was found between the activity of both enzymes in one neuron, although this correlation was certainly not linear. Many neurons exhibited a stronger signal for one enzyme. A very small part of the positive nerve cells showed intense staining for both AchE and NADHd. The NADPHd technique demonstrated that the NADPHd‐positive neurons fill the negative intraganglionic spaces in the ganglia. Double staining with the two other enzymes showed virtually no colocalization of NADPHd with either NADHd or AchE in the porcine jejunal enteric ganglia. Little negative intraganglionic spaces were seldom found, leaving room for perhaps still more negative enteric neurons. Based upon these results we suggest that the enteric neurons of the porcine small intestine can be subdivided into AchE‐NADHd and NADPHd subpopulations. Since the latter colocalizes with the neuronal NO synthase enzyme, we further suggest a subdivision of the enteric nerve cells into AchE‐NADHd and NOS‐NADHd neurons. © 1994 Wiley‐Liss, Inc.