bluuebunny/crossref_metadata_2025_split huggingface dataset:
The ultrastructure of mammalian pinealocytes: A systematic investigation
Authors: Bhatnagar Kunwar P. 
Published: February 2005

AbstractPinealocytes are not only the principal cellular components of the pineal gland, but they are also the principal synthetic machinery of this enigmatical gland with highly diverse and often questionable empyreal roles assigned to it. Ultrastructural descriptions of pinealocytes belonging to some 70 species of mammals (a mere 2% or less of the over 4,200 mammalian species) have been summarized from the available literature with new observations on 12 species of chiropterans. Space limitation precluded any treatment of the supporting glia, neural elements, and the perivascular spaces. A detailed table lists nearly all mammalian species whose pineal ultrastructure has been investigated. Blanks in this table point to the necessity of studies on those particular groups. A tabular listing of unusual structures reported within the pinealocyte cytoplasm points out the impending experimental work on these species. Such studies using the latest techniques might provide clearer insights into the functional role of the pineal gland as an important and integral component of the neuroendocrine axis. Whereas sufficient structural information now exists on cytoplasmic organelles such as synaptic ribbons and spherules, annulate lamellae, subsurface cisterns, and the several types of synaptic arrangements seen in relation to the pinealocyte soma and its processes, the functional role of these structures in pineal synthetic processes remains to be elucidated.
Morphofunctional aspects of the mammalian pineal gland
Authors: Karasek Michal , Reiter Russel J. 
Published: February 2005

AbstractThe primary aim of this review is to present the current state of knowledge of the ultrastructure of the mammalian pineal gland, with emphasis on its functional aspects. Basic ultrastructural features of the mammalian pinealocytes are presented with special attention paid to ultrastructural aspects of pineal secretion.
The embryonic pineal body as a multipotent organ
Authors: Watanabe Kenji , Araki Masasuke , Iwasaki Hiromichi 
Published: February 2005

AbstractThe repertoire of differentiating potency of mammalian and avian pineal cells has been examined utilizing cell culture technique. Skeletal muscle fibers are differentiated from pineal cells of the rat under the usual culture condition and from those of quail under hypertonic conditions. Myogenesis of pineal cells may be explained from the ontogeny of the pineal body. Anlagen of a pineal body are situated in bilateral cephalic neural folds, which also supply multipotent neural crest cells. In some conditions, almost all quail pineal cells are able to differentiate into pigmented epithelial cells and/or lens cells. Opsin containing cells found in culture of rat pineal cells may be in a similar category reflecting the “third eye”: the phylogenetic ancestor of the pineal body of avian and mammalian species. Neuron‐like cells have also been reported and neuronal morphology has been intensified under the effect of testicular hyaluronidase. The cytodifferentiation described above is suggested to be different expressions of a single type of progenitor cells in the pineal body. In relation to multipotentiality of pineal cells, the original differentiating state of pineal cells is interesting; it has been found that tyrosinase is expressed from the beginning of pineal formation and that its expression is stage‐specific (during embryonic period) and site‐specific (predominance in the dorsal half of the pineal body and in the apical cytoplasm of the pineal cell). In the 8 day quail embryo used for culture studies, three differentiating states as to tyrosinase are noticed. However, the distinction may be apparent, as even the cells negative in tyrosinase in this stage are still ready to express tyrosinase in the suitable culture condition. Pineal cells are flexible and surprisingly susceptible to environmental factors and useful for the study of cell differentiation in general. © 1992 Wiley‐Liss, Inc.
The microcomputer and image analysis in diagnostic pathology
Authors: Jarvis L. R. 
Published: February 2005

AbstractThis paper presents a snapshot view of the influence and direction of microcomputer technology for image analysis techniques in diagnostic pathology.Microcomputers have had considerable impact in bringing image analysis to wider application. Semi‐automated tracing techniques are a simple means of providing objective data and assist in a wide range of diagnostic problems. From the common theme of reducing subjectivity in diagnostic assessment, an extensive body of research has accrued. Some studies have addressed the need for quality control for reliable, routine application.Video digitizer cards bring digital image analysis within the reach of laboratory budgets, providing powerful tools for investigation of a wide range of cellular and tissue features. The use of staining procedures compatible with quantitative evaluation has become equally important. As well as assisting scene segmentation, cytochemical and immunochemical staining techniques relate the data to biological processes.With the present state of the art, practical use of microcomputer based image analysis is impaired by limitations of information extraction and specimen throughput. Recent advances in colour video imaging provide an extra dimension in the analysis of multi‐spectral stains. Improvements will also be felt with predictable increase in speed of microprocessors, and with single chip devices which deliver video rate processing. If the full potential of this hardware is realized, high‐speed, routine analysis becomes feasible. In addition, a microcomputer imaging system can play host to companion functions, such as image archiving and transmission.With this outlook, the use of microcomputers for image analysis in diagnostic pathology is certain to increase. However, it is the software in both design and concept which ultimately governs the performance which can be achieved. Progress may be made by structured software techniques, by application of mathematical principles, or by use of expert systems for data or image interpretation. © 1992 Wiley‐Liss, Inc.
Preservation and visualization of the sea urchin embryo blastocoelic extracellular matrix
Authors: Cherr Gary N. , Baldwin John D. , Summers Robert G. , Morrill John B. 
Published: February 2005

AbstractSeveral methods were utilized to visualize the structure and orientation of the blastocoelic extracellular matrix (ECM) in Strongylocentrotus purpuratus embryos at the mesenchyme blastula stage. Rapid freezing in liquid propane cooled to LN2 temperatures followed by freeze substitution was used to preserve the ECM without shrinkage due to dehydration. Scanning, transmission, and light microscopy were employed to elucidate the ECMs' structure. The blastocoelic ECM consisted of parallel fibrillar sheets that were interconnected by finer filaments and oriented along the animal‐vegetal axis. The ECM completely filled the blastocoelic cavity as viewed by scanning electron microscopy. The basal lamina could be distinguished from the blastocoelic ECM as a thin coat on the plasma membrane of epithelial cells; the ECM was in contact with this coat. In contrast, the blastocoelic ECM attached directly to the plasma membrane of primary mesenchyme cells (PMC) which did not possess a basal lamina. The blastocoelic ECM was isolated as an intact “bag” and probed in a hydrated state with Con A and alcian blue. Confocal microscopy confirmed that the entire blastocoel was filled with a fibrillar ECM. These approaches offer advantages for future studies of the ECMs of sea urchin embryos and their roles in gastrulation. © 1992 Wiley‐Liss, Inc.
Ultrastructural imaging of freeze‐fractured plant cells in the scanning electron microscope
Authors: Barnes Susan H. 
Published: February 2005

AbstractThe application of the freeze‐fracture and cytoplasmic maceration technique in ultrastructural studies of plant cells is described. A major advantage of the technique is, that by extracting mobile cytoplasmic components from the freeze‐fractured cells, surface relief is introduced and three‐dimensional information is obtainable. The details of specimen preparation are described and the results obtained are reviewed. The use of chitosan embedding for very small or fragile specimens is described. © 1992 Wiley‐Liss, Inc.
Freeze‐substitution of chemically stabilized samples for biological field emission scanning electron microscopy
Authors: Peters Klaus‐Ruediger , Pohl Roderike 
Published: February 2005

AbstractThe high resolution imaging capabilities of modern field emission scanning electron microscopes require adequately improved tissue preparation procedures to prevent the collapse of macromolecular structures and the extraction of molecules. A routine cryo‐stabilization technique is described which utilizes chemical crosslinking and cryo‐dehydration for mechanical and chemical stabilization of protein and lipid structures and increase of electrical conductivity of the sample. Thiocarbohydrazide (TCH) serves as a general mordant for osmium tetroxide crosslinking. However, extensive washing after all impregnation steps is necessary to dissolve unspecific osmium black precipitations at the sample surface. Collagen I aggregates showed increased stability against collapse after TCH osmification alone, whereas pulmonary surfactant liposomes require additional freeze‐substitution in methanol and Freon 113 for stabilization during critical point drying. Environmental scanning electron microscopy (at water vapor pressures of 5–10 torr within the specimen chamber) was used to control, in the wet phase, the stabilization procedure at the level of chemical crosslinkage. It could be confirmed that tannic acid, often used to stabilize lipids, eads to artificial rearrangement of bilayered liposomes into compact presumable multilayered bodies, whereas the TCH osmification preserved liposome structures and their aggregates. The increase of electrical conductivity of sliced tissue was demonstrated on kidney. Support technologies for the cryo‐stabilization procedures are described in detail, as well as simple routines for first stabilization trials with new samples. On pulmonary tissue, the excellent preservation of alveolar shape and fine structures of intermediate forms of surfactant are described. © 1992 Wiley‐Liss, Inc.
Suspected chemoreceptors in coelenterates and ctenophores
Authors: Kass‐Simon G. , Hufnagel L. A. 
Published: February 2005

AbstractChemoreceptors in coelenterates and ctenophores have not been identified with certainty. Among prospective chemoreceptive cells are the sensory nerve cells, the cnidocyst bearing cnidocytes, and the epitheliomuscular cells that are likely to be involved in feeding or aggression. Both behaviors are mediated by coordinated chemical and mechanical reception. This is reflected in the close apposition of putative chemo‐ and mechanoreceptors. Among the structures that have been designated as likely chemo‐ and/or mechanoreceptors are stereocilia, kinocilia, and/or microvilli which are universally present on all the putative chemoreceptor complexes, while gland cells and mucous secretions are prevalent. Evidence that the actin‐containing stereocilia are chemically modulated mechanoreceptors is presented for several forms. © 1992 Wiley‐Liss, Inc.
Fine structure of olfactory sensilla in myriapods and arachnids
Authors: Tichy Harald , Barth Friedrich G. 
Published: February 2005

AbstractStructural features of various types of olfactory sensilla are reviewed. (1). Sensilla basiconica which differ in form and size are found on the antennae of centipedes and millipedes. Their walls show longitudinal slits or grooves that either open into the sensillum lumen or do not penetrate the cuticle. In other such sensilla the outer surface is pierced by pores and the inner surface grooved and pocketed. These sensilla are innervated by one to six sensory cells. Their unbranched outer dendritic segments extend to the tip of the sensillum. The sensory cells are surrounded by two or three sheath cells which terminate at the sensillum base or form a continuous tube around the entire length of the outer dendritic segments. (2) Temporal organs of centipides are located between the insertion of the antenna and the ocelli. These sensilla consist of a shallow cuticular ring with a central sensory plate made up by a layer of unperforated cuticle or a capsule with a mushroom‐shaped structure inside formed by fibrous‐looking cuticle. A dozen sensory cells with unbranched outer dendritic segments innervate each sensillum. They extend toward the sensory cuticle and pass just below it. Numerous sheath cell processes run parallel to the outer dendritic segments up to the sensory cuticle. (3) Thread‐like flagella of Pauropoda are found on the antennae. They possess a flexible unperforated cuticular wall. These sensilla contain nine sensory cells surrounded by several sheath cells which form a continuous cytoplasmic tube around the outer dendritic segments. (4) Single‐walled sensilla with numerous plugged pores penetrating the cuticular wall occur on the tarsus of the first leg in ticks. Each sensillum is innervated by 4–15 sensory cells. Three sheath cells terminate in the base of the sensillum. (5) Double‐walled sensilla with spoke canals are found on the first tarsus of ticks. Their shaft is longitudinally grooved. Pore canals lead inward from the bottom of the grooves and open into vase‐shaped chambers. From its base these canals extend into the lumen of the sensillum which contains unbranched outer dendritic segments of 1–2 sensory cells. (6) Single‐walled sensilla with pore openings occur on the distal tarsal segments of the first leg of whip spiders. These sensilla are innervated by 40–45 sensory cells. Their unbranched outer dendritic segments fill the shaft lumen and extend partly into the wall pores. Microvillus‐shaped sheath cell processes line the inner surface of the cuticular wall. (7) Tarsal organs are located dorsally on the tarsus of all legs and pedipalps of spiders. These sensory organs consist of a cuticular capsule with a dome‐shaped projection inside. It is situated on the proximal sidewall of the capsule and possesses 7 pore canals that enclose the dendritic tips of 2–3 sensory cells, giving a total of 20 sensory cells. Each group of dendrites terminating in an individual pore canal is encased by 2 sheath cells. © 1992 Wiley‐Liss, Inc.
Hapten‐tagged plasma proteins as immunocytochemical probes for the study of vascular permeability
Authors: Ghitescu Lucian , Bendayan Moïse 
Published: February 2005

AbstractBovine serum albumin and transferrin were covalently coupled with fluorescein isothiocyanate and digoxigenin, respectively, and intravenously co‐injected in equal amounts in mouse. The derivation of the two proteins induces minor alterations of their physicochemical properties as well as of their physiological functions. The two tracers were revealed within vascular and extravascular compartments of diaphragm by quantitative postembedding immunocytochemistry, using antibodies against each of the haptens in conjunction with the protein AG‐gold complexes. The influence of different fixatives and embedding protocols on the immunodetectability of the hapten‐tagged proteins was assessed. Both resist reasonably well to osmication and embedding in Epon. None of the haptens reacted with the heterologous antibody. At 30 minutes after injection, the tracers were detected in blood plasma, interstitium, and endothelial plasmalemmal vesicles. The presence of both proteins within the interendothelial clefts was inconspicuous. The ratios between the labeling densities found over endothelium, interstitial space, and vascular lumen were similar for both tracers. This suggests that the endothelium of mouse diaphragm capillaries might exhibit comparable permeabilities towards serum albumin and transferrin which are similar in size and charge. The study shows that hapten‐tagged polypeptides are close to the corresponding native macromolecules, and represent interesting tools for the morphological study of dynamic processes such as transcytosis. © 1992 Wiley‐Liss, Inc.
Phylogeny of the vomeronasal system and of receptor cell types in the olfactory and vomeronasal epithelia of vertebrates
Authors: Eisthen Heather L. 
Published: February 2005

AbstractIn this paper, the evolutionary origin of the vomeronasal system as a discrete sensory system separate from olfaction is examined. The presence of a discrete vomeronasal system appears to be a derived character in tetrapods, and its presence in larval amphibians indicates that the system did not arise as a terrestrial adaptation. The vomeronasal system has been lost independently in several taxa, including crocodilians, some bats, cetaceans, and some primates. The presence of microvillar receptor cells in the vomeronasal epithelium appears to be the ancestral condition for tetrapods, and alternative hypotheses concerning the ancestral condition for receptor cell types in the vertebrate olfactory epithelium are discussed. Finally, the possibility that the vomeronasal system is present in some fishes in a form that has not been recognized is discussed in relation to the phylogenetic distribution of receptor cell types in vertebrates. © 1992 Wiley‐Liss, Inc.
Ciliated and microvillar receptor cells degenerate and then differentiate in the olfactory epithelium of rainbow trout following olfactory nerve section
Authors: Zielinski Barbara S. , Hara Toshiaki J. 
Published: February 2005

AbstractWe used scanning (SEM) and transmission (TEM) electron microscopy to examine ultrastructural changes in the olfactory epithelium (OE) of rainbow trout following unilateral olfactory nerve section. Both ciliated receptor cells (CRC) and microvillar receptor cells (MRC) degenerated and subsequently differentiated from unidentified precursor cells. The following changes took place in fish that were held at 10°C at the stated period following olfactory nerve section: on day 7, MRC and CRC contained intracellular vacuoles; on day 12, the olfactory knobs appeared disrupted; by day 26, olfactory receptor cells were absent from the OE; on day 42, there were receptor cell bodies and a few CRC with short cilia at the apical surface; and opn day 55, a small number of both CRC and MRC had differentiated. By day 76, both CRC and MRC repopulated the OE. Degenerative changes in the cytoplasm of the sustentacular cells (SC) and ciliated nonsensory cells (CNC) were observed in the first 26 days following olfactory nerve section, but these cells remained intact throughout the experiment. The degeneration and subsequent differentiation of CRC and MRC supports and extends previous observations that both cells types are olfactory receptor neurons with axons that extend along the olfactory nerve to the olfactory bulb. © 1992 Wiley‐Liss, Inc.
Morphology of olfactory epithelium in humans and other vertebrates
Authors: Morrison Edward E. , Costanzo Richard M. 
Published: February 2005

AbstractHuman olfactory epithelium is similar in organization and cell morphology to that of most vertebrate species. The epithelium has a pseudostratified columnar organization and consists of olfactory neurons, supporting and basal cells. Near the mucosal surface there are also microvillar cells. These cells have neuron‐like features and may be chemoreceptors. Human olfactory epithelium is not a uniform sensory sheet. Patches of non‐sensory tissue often appear in what was thought to be a purely olfactory region. The significance of these patches has not been determined, but they could reflect exposure to environment agents or changes that occur during the normal aging process.In order to better understand the human olfactory system, further knowledge of the normal structure is necessary. This review addresses the morphology of the human olfactory epithelium and the remarkable plasticity of the vertebrate olfactory system. © 1992 Wiley‐Liss, Inc.
Fine structure of the vomeronasal and septal olfactory epithelia and of glandular structures
Authors: Adams Donald R. 
Published: February 2005

AbstractThe vomeronasal and septal olfactory organs are two neurosensory structures in the mammalian nasal septum which are poorly understood relative to the main olfactory system. The vomeronasal organ is a paired, blind‐ending tubular structure that opens rostrally into the nasal cavity in some species and into the incisive ducts in others. When present in mammals, the septal olfactory organ is an island of olfactory mucosa positioned such that it is in the primary air pathway in the caudal portion of the nasal cavity. Mammalian nasal glands, with a diverse histochemical and ultrastructural morphology, secrete a variety of substances onto the mucosal surface. One of these substances, odorant binding protein, localized in bovine nasal glands and lateral nasal glands of rodents may be important in the capture and conveyance of odorant molecules to olfactory receptors. The objectives of this paper are to present original data while reviewing the literature on the ultrastructure of vomeronasal and septal olfactory neuroepithelia, and of vomeronasal, bovine nasal, and lateral nasal glands. Nasal tissues from pigs, calves, and hamsters were prepared for electron microscopy. Neurosensory epithelia of the porcine vomeronasal organ and the hamster septal olfactory organ are similar to that described for the vomeronasal and septal olfactory organs of other mammals. Bovine nasal and rodent lateral nasal glands consist of subregions which differ morphologically; the most abundant acinar cell type in the bovine nasal gland contains lightly electron dense secretory granules while that of the rodent lateral nasal gland contains both small electron dense and large, electron lucent granules. The porcine vomeronasal gland contains numerous small, dense granules of a diverse morphology. © 1992 Wiley‐Liss, Inc.
Fine structural aspects of secretion and extrinsic innervation in the olfactory mucosa
Authors: Getchell Marilyn L. , Getchell Thomas V. 
Published: February 2005

AbstractThe mucus at the surface of the olfactory mucosa constitutes the milieu in which perireceptor events associated with olfactory transduction occur. In this review, the ultrastructure of olfactory mucus and of the secretory cells that synthesize and secrete olfactory mucus in the vertebrate olfactory mucosa is described. Bowman's glands are present in the olfactory mucosa of all vertebrates except fish. They consist of acini, which may contain mucous or serous cells or both, and ducts that traverse the olfactory epithelium to deliver secretions to the epithelial surface. Sustentacular cells are present in the olfactory epithelium of all vertebrates. In fish, amphibia, reptiles, and birds, they are secretory; in mammals, they generally are considered to be “nonsecretory,” although they may participate in the regulation of the mucous composition through micropinocytotic secretion and uptake. Goblet cells occur in the olfactory epithelium of fish and secrete a mucous product.Secretion from Bowman's glands and vasomotor activity in the olfactory mucosa are regulated by neural elements extrinsic to the primary olfactory neurons. Nerve fibers described in early anatomical studies and characterized by immunohistochemical studies contain a variety of neuroactive peptides and have several targets within the olfactory mucosa. Ultrastructural studies of nerve terminals in the olfactory mucosa have demonstrated the presence of adrenergic, cholinergic and peptidergic input to glands, blood vessels, and melanocytes in the lamina propria and of peptidergic terminals in the olfactory epithelium. The neural origins of the extrinsic nerve fibers and terminals are the trigeminal, terminal, and autonomic systems. © 1992 Wiley‐Liss, Inc.