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  • 1975-1979  (3,871)
  • 1890-1899  (195)
  • Cell & Developmental Biology  (2,913)
  • Electron microscopy  (597)
  • Ultrastructure  (563)
Source
Material
Years
Year
Keywords
  • 101
    Electronic Resource
    Electronic Resource
    Ultrastructural study of medullomyoblastoma (1979)
    Springer
    Acta neuropathologica 48 (1979), S. 211-214 
    Details
    ISSN: 1432-0533
    Keywords: Medullomyoblastoma ; Desmoplastic medulloblastoma ; Teratoid ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of cerebellar medullomyoblastoma in a young boy was investigated by electron microscopy. The neuroectodermal component shows the characteristics of a desmoplastic medulloblastoma. The mesodermal component consists of more or less differentiated cross-striated muscle cells. Undifferentiated muscle cells are very similar to proliferated endothelial cells of blood vessels within the muscular component, so that an origin of this component from pluripotential endothelial cells of the vessel wall is suggested. This tumor is considered a malignant teratoid because of the derivation from two blastodermic layers and because of the midline localization in children suggesting a malformative origin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00690521
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  • 102
    Electronic Resource
    Electronic Resource
    Intrahypothalamic connections: An electron microscopic study in the rat (1979)
    Springer
    Experimental brain research 34 (1979), S. 201-215 
    Details
    ISSN: 1432-1106
    Keywords: Intrahypothalamic connections ; Deafferentation ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Terminal degeneration within the hypothalamus was studied by electron microscopy 1 or 2 days (1) after carefully placed microlesions in the arcuate, anterior periventricular, ventromedial, premammillary and posterior hypothalamic nuclei and (2) after microlesions placed in the hypothalamus deafferented 3 weeks earlier. In the median eminence terminal degeneration was found after each of these lesions. Projections from the ventromedial nucleus reach the arcuate, suprachiasmatic, and anterior periventricular nuclei. Projections from the arcuate nucleus terminate in the medial preoptic, anterior periventricular, and ventromedial nuclei. After lesioning the premammillary nuclei degeneration was found in the supraoptic, arcuate, anterior hypothalamic and ventromedial nuclei.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235668
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  • 103
    Electronic Resource
    Electronic Resource
    The fine structure of neurones and cellular relationships in the abducens nucleus in the cat (1979)
    Springer
    Experimental brain research 35 (1979), S. 249-267 
    Details
    ISSN: 1432-1106
    Keywords: Abducens nucleus (cat) ; Peroxidase ; Neurones ; Synapses ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Light and electron microscope studies of the abducens nucleus in the cat have disclosed two populations of neurones: large neurones 25 to 75 μm in diameter and small neurones 10 to 25 μm in diameter. Characteristic of the large neurones are a highly developed granular endoplasmic reticulum and a large number of axo-somatic synapses. The small neurones have a poorly developed granular endoplasmic reticulum and comparative by few axo-somatic synapses. Injection of horseradish peroxidase (HRP) into the ipsilateral lateral rectus muscle has been used to identify abducens motoneurones which represent 65% of the total number of cells in the abducens nucleus and form part of the large cell population. The remaining unlabelled large neurones (30% of the large cell population) probably represent motoneurones of the retractor bulbi muscles, abducens motoneurones which have failed to transport the HRP, and possibly internuclear neurones. The small neurones (5% of the total cell population) were never labelled by HRP. Axo-somatic and axo-dendritic synapses are numerous. Many of the synaptic terminals form contacts with two or more different postsynaptic elements. Axo-axonic synapses and synapses on the initial segments of large neurones are also present. Nodal synapses and branching of myelinated axons are common findings. Finally, extended areas of close apposition between dendritic membranes are frequently observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236614
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  • 104
    Electronic Resource
    Electronic Resource
    Identification and distribution of the spinal and hypophyseal projection neurons in the paraventricular nucleus of the rat. A light and electron microscopic study with the horseradish peroxidase method (1979)
    Springer
    Experimental brain research 35 (1979), S. 315-331 
    Details
    ISSN: 1432-1106
    Keywords: Hypothalamic paraventricular nucleus ; Spinal projection neuron ; Hypophyseal projection neuron ; Horseradish peroxidase ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution of labeled neurons in the paraventricular nucleus of the hypothalamus (PVN) was studied following injections of horseradish peroxidase (HRP) into the spinal cord (C8 to T1) or the hypophysis in the rat. Injections were also made in the spinal cord in another group of animals, which were subjected to water deprivation for a period of 3 days, and the PVN of these animals was examined with the electron microscope. Spinal projection neurons (paraventriculospinal tract, PVST, neurons) formed two groups; the dorsal and the ventral groups. They were located within the parvocellular part of the PVN and fused into one at the caudal level. The neurons of the dorsal group were well assembled whereas those of the ventral group were intermingled with paraventriculohypophyseal tract (PVHT) neurons, which were concentrated in the magnocellular part. Electron microscopic observations revealed that HRP-labeled neurons after spinal injections did not contain neurosecretory granules and that they were not affected by water deprivation. On the other hand, neurons containing a number of neurosecretory granules displayed a significant degree of dilatation of the endoplasmic reticulum as the result of water deprivation. These neurons contained no HRP granules. The present findings suggest that the PVST neurons are distinct from the PVHT neurons and that the neuronal groups of both systems form different cell columns within the nucleus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236618
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  • 105
    Electronic Resource
    Electronic Resource
    Ultrastructural data, with special reference to bouton/glial relationships, from the hypoglossal nucleus after a second axotomy of the hypoglossal nerve (1979)
    Springer
    Experimental brain research 36 (1979), S. 107-118 
    Details
    ISSN: 1432-1106
    Keywords: Rat ; Hypoglossal nucleus ; Ultrastructure ; Second axotomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The left hypoglossal nerve of adult male albino rats was prevented from regenerating to the tongue after a distal axotomy by implanting the proximal stump into normally innervated left sternomastoid muscle. Eighty-four days after implantation, the hypoglossal nerve was transected again and its regeneration to the tongue unimpeded. From 8 to 70 days after this second axotomy the left hypoglossal nuclei were processed for quantitative ultrastructural analysis. The first aim of this study was to compare regeneration success in the hypoglossal nucleus after second axotomy with that accompanying outgrowth of the hypoglossal nerve into denervated sternomastoid muscle. During quantitative analysis a second aim developed, of elucidating bouton/glial relationships. The second axotomy induced loss and return of subsurface cisterns, dispersal and reassembly of Nissl substance, increase and decrease of microglial numbers, slight further loss and partial return of boutons with clear spherical vesicles and symmetrical synapses, slight increase and decrease of boutons with clear flat vesicles and symmetrical synapses, regrowth of retracted dendrites and restoration of their synapses, and gradual diminution of numbers of electron-dense neurones and dendrites. Astrocytes remained hypertrophied throughout. When compared with events in the hypoglossal nucleus accompanying innervation of denervated sternomastoid muscle by the hypoglossal nerve, the results suggest (1) that regeneration of the hypoglossal nerve to its own tongue muscle instead of to a foreign muscle caused no acceleration of recovery in the hypoglossal nucleus, and (2) that the microglial response is dependent on nerve integrity and not on bouton behaviour.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238471
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  • 106
    Electronic Resource
    Electronic Resource
    The trabecular meshwork of a non-glaucomatous eye with the exfoliation syndrome (1979)
    Springer
    Virchows Archiv 384 (1979), S. 347-355 
    Details
    ISSN: 1432-2307
    Keywords: Exfoliation syndrome ; Non-glaucomatous eye ; Trabecular meshwork ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The trabecular meshwork of a non-glaucomatous eye with the exfoliation syndrome was investigated. The exfoliation material was found mainly in massive deposits in the subendothelial region of the outer and inner wall of Schlemm's canal, in the cribriform area and the uveal meshwork. The other alterations of the trabeculum corneosclerale corresponded to the age of the patient. The concept that the accumulation of exfoliation material is an important pathogenetic factor in the development of glaucoma was not confirmed by this study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00428235
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  • 107
    Electronic Resource
    Electronic Resource
    Light and electron microscopic findings in five cases of cryoglobulinemic glomerulonephritis (1979)
    Springer
    Virchows Archiv 384 (1979), S. 29-44 
    Details
    ISSN: 1432-2307
    Keywords: Glomerulonephritis ; Cryoglobulinemia ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Renal tissue from five patients with cryoglobulinemia was studied by light and electron microscopy and immunofluorescence. None of the histologic features observed at the light microscopic level seems to be specific for cryoglobulinemia. Electron microscopic investigations have shown very large electron dense deposits in almost every examined lobule in all cases. The deposits displayed two main patterns; a homogeneous texture in two cases and tubular or annular structures in three cases. The patients with typically structured deposits had IgG-IgM cryoglobulinemia (2 cases) or monoclonal IgM cryoglobulinemia (1 case). The presence of IgM in cryoglobulinemia may be the cause of the peculiar structure of the deposits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00427149
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  • 108
    Electronic Resource
    Electronic Resource
    Adrenal adenomata causing primary aldosteronism (1979)
    Springer
    Virchows Archiv 384 (1979), S. 93-102 
    Details
    ISSN: 1432-2307
    Keywords: Primary aldosteronism ; Adrenal adenomata ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Adenomata taken from 25 patients with primary aldosteronism were observed by electron microscopy. The cells in the adenoma had a well developed agranular endoplasmic reticulum but granular endoplasmic reticulum was not prominent. Most of the mitochondria resembled those in the cells of the zona glomerulosa, suggesting that the adenomata which caused primary aldosteronism are derived from this zone. Spironolactone bodies were found in the cells of the adenoma from a patient who received spironolactone. Their appearance was identical to that descrived in previous reports.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00427154
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  • 109
    Electronic Resource
    Electronic Resource
    Adrenergic innervation of the eighth nerve and vestibular end organs in man (1979)
    Springer
    European archives of oto-rhino-laryngology and head & neck 224 (1979), S. 17-23 
    Details
    ISSN: 1434-4726
    Keywords: Eighth nerve ; Inner ear ; Human ; Fluorescence microscopy ; Electron microscopy ; Menière ; Neurilemoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fluorescence microscopy was used to examine the adrenergic, bloodvessel-independent innervation of the 8th nerve and inner ear specimens in patients with otoneurological diseases. Specifically fluorescent adrenergic axons were scantily seen among the myelinated nerve fibers in the 8th nerve and in the subepithelial regions of the end organs but not in the endolymphatic sac.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00455219
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  • 110
    Electronic Resource
    Electronic Resource
    Functions of different receptor systems in the reptilian labyrinth (1979)
    Springer
    European archives of oto-rhino-laryngology and head & neck 224 (1979), S. 31-35 
    Details
    ISSN: 1434-4726
    Keywords: Intracellular potentials ; Ultrastructure ; Hair cells ; Labyrinth receptors ; Reptilia (Crocodilia, Gekkonidae)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Different biopotentials, following a mechanical stimulus, were recorded from single hair cells of the reptilian labyrinth, with electronoptically circumscript localizations: 1. From the apical cell pole, the receptor potential, intracellular or from the ciliary surface, within the physiological range proportional to stimulus amplitude, frequency or phase, without delay, and with no real threshold of mechanosensitivity, as measured by ciliary displacement amplitude or velocity. 2. From the synaptic zone, in the basal region of the hair cell, or from contacting nerve endings, the synaptic potentials, local excitatory or inhibitory processes, respectively, with measurable latencies and with non-linear distortion. 3. From the (dendritic) endings of the first afferent neuron (or neurons), spike-shaped action potentials, synchronized by the (excitatory) synaptic potentials. Characteristic curves were plotted as a quantitative representation of the mechano-electric input-output relations of the different types of hair cells. For proceeding morphological and physiological system analysis, the comparison of the different submammalian inner-ear receptor systems gives us some new possibilities of a closer correlation between ultrastructure and function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00455221
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  • 111
    Electronic Resource
    Electronic Resource
    The effects of anaerobiosis and metabolic inhibitors on mitochondrial ultrastructure inAmoeba proteus (1979)
    Springer
    Protoplasma 99 (1979), S. 275-288 
    Details
    ISSN: 1615-6102
    Keywords: Amoeba proteus ; Anaerobiosis ; Metabolic inhibitors ; Mitochondria ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Anaerobiosis or exposure to the metabolic inhibitors potassium cyanide and Antimycin A produced changes in the form of living amoebae. These were accompanied by mitochondrial changes in fixed cells. Increasing the anaerobic period increased the percentage of mitochondria affected and resulted in a gradual reduction and eventual loss of the condensed Type I mitochondria ofAmoeba proteus. The rounder Type II mitochondria were not lost but underwent varying degrees of disruption, vesiculation of the cristae being evident after 5 hours exposures and matrical inclusions after 18 hours exposures. Similar cristal vesiculation was seen after 30 minutes treatments with potassium cyanide. Providing treatments were terminated before cell viability was lost, all mitochondrial abnormalities were reversible on return to normal culturing conditions. The longer the period of anaerobiosis the longer was the recovery time required for the return of normal mitochondrial structure and the re-equilibration of control Type I to Type II mitochondrial frequencies. The relationship between mitochondrial conformation and functional integrity is discussed in the light of these findings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01275801
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  • 112
    Electronic Resource
    Electronic Resource
    Ultrastructural morphometry of blastogenesis I: Transformation of small lymphocytes stimulated in vivo with dinitrochlorobenzene (1979)
    Springer
    Cell & tissue research 200 (1979), S. 495-509 
    Details
    ISSN: 1432-0878
    Keywords: T-lymphocytes ; Blast cells ; Lymph node ; Electron microscopy ; Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Changes in the volumes and surfaces of subcellular compartments of unstimulated small lymphocytes and immunoblasts in mouse axillary lymph nodes have been established using stereological techniques. Blast transformation was induced in vivo with dinitrochlorobenzene (DNCB). Cell samples were obtained by random sampling regimes applied at light and electron microscopic levels. From electron micrographs the volume densities of euchromatin, heterochromatin, nucleoli, mitochondria, Golgi apparatus and rough endoplasmic reticulum were determined. Cell surface/volume ratios were also computed. By estimating mean nuclear volumes using light microscopy, it was possible to calculate absolute compartmental volumes and to evaluate the plasma membrane surface areas of average cells. Transformation in this model was characterized by a considerable cellular hypertrophy and a substantial increase in plasmalemma surface. Hypertrophy was the consequence of increases in the volumes of all measured intracellular compartments, notably euchromatin and “residual cytoplasm” (including ground cytoplasm and free ribosomes). These changes are discussed in the context of the altered metabolic status of cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234859
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  • 113
    Electronic Resource
    Electronic Resource
    A new morphological aspect of the brush cells of the mouse gallbladder epithelium (1979)
    Springer
    Cell & tissue research 201 (1979), S. 37-44 
    Details
    ISSN: 1432-0878
    Keywords: Brush cell ; Receptor ; Lateral microvilli ; Gallbladder ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The brush cells of the gallbladder epithelium of the mouse have microvilli not only at their luminal border but also on their lateral surface, from the level of the nucleus to the junctional complex. The lateral microvilli radiate from the brush cell in all directions, contain a core of filaments, and penetrate up to 3 μm into the adjacent cells. The microvilli in these locations display small desmosomes at their base.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238045
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  • 114
    Electronic Resource
    Electronic Resource
    Activation of human T-lymphocytes (1979)
    Springer
    Cell & tissue research 201 (1979), S. 101-127 
    Details
    ISSN: 1432-0878
    Keywords: T-lymphocytes ; Cell activation ; Stereology ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Stereological data of phytohaemagglutinin (PHA)-activated human T-lymphocytes were recorded at intervals (12 to 72 h) together with biochemical (isotope-uptake, lymphotoxin-release) and morphological measurements. About 98 % of the cells were activated 12 h after PHA-stimulation. The activation phase lasted less than 48 h, i.e., cells entering the activation phase within 12 h were at their activation maximum by 48 h. The activated cell increased in size. The nuclear/cytoplasmic-ratio decreased. Most of the cytoplasmic organelles developed in phase with the increase of cytoplasmic volume. After 48 h, mitotic figures were frequently seen. Due to the increasing number of secondary, activated daughter cells, parameters of most cytoplasmic components declined between 48 and 72 h. Structural changes in the nucleus preceded the 3H-leucine uptake, which had not reached its maximum after 72 h of incubation. The 3H-leucine uptake started as early as 12 h after culture initiation, and its increase was proportional to the increasing polyribosome density. No maximum uptake was reached up to 72 h, but the development of structural components related to this uptake was at its maximum at the end of the activation phase (48 h). The formation of bound ribosomes occurred subsequent to the enlargement of the surface of the rough endoplasmic reticulum. Initial polysome formation occurred at the expense of existing free ribosomes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238051
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  • 115
    Electronic Resource
    Electronic Resource
    Maturation of secretory granules in the endosalpinx one to four days post coitum in sheep (1979)
    Springer
    Cell & tissue research 201 (1979), S. 145-158 
    Details
    ISSN: 1432-0878
    Keywords: Ultrastructure ; Secretory granules ; Endosalpinx ; Sheep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of granules in the secretory cells of the endosalpinx of 20 Merino ewes was examined on days 1, 2, 3, and 4 post coitum. Based on the different frequency of granules of different size and structure on days one to four post coitum, one can assume that the ovoid, membrane bounded secretory granules mature in five successive stages. In stage I small, electron-lucent vesicles with a finely granulated and filamentous content become apparent, initially in the neighbourhood of the Golgi complex. In stage II the granules become larger and progressively more eletron-dense by an increase of the granulated material. In stage III, the primarily granulated content forms membranes, that lie in characteristic stacks at different angles to one another, separated by electron-dense areas. This structure fragments when the granule comes to lie beneath the surface of the cell (stage IV) and opens into the lumen of the oviduct, where its content is discharged in membrane fragments or vesicles (stage V). This discharge is mainly observed shortly before the egg is transported into the uterus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238054
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  • 116
    Electronic Resource
    Electronic Resource
    Ultrastructural responses of pancreatic β cells to metabolic alkalosis (1979)
    Springer
    Cell & tissue research 201 (1979), S. 159-163 
    Details
    ISSN: 1432-0878
    Keywords: Insulin secretion ; Acid-base changes ; Electron microscopy ; Pancreas perfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural changes in pancreatic β cells were studied following glucose-induced insulin secretion in vitro, at two different extracellular pH (7.4 and 7.8). The pancreata perfused at pH 7.4 exhibited a biphasic insulin response to glucose challenge together with signs of increased emiocytotic activity and numerous microtubules in the β cells. Conversely, the pancreata perfused at pH 7.8 showed a significant decrease in insulin secretion, and their β cells revealed scarce emiocytotic images and a marked increase of intracellular granulolysis. These results represent the ultrastructural correlate of the reduced insulin secretion produced by metabolic alkalosis in the perfused rat pancreas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238055
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  • 117
    Electronic Resource
    Electronic Resource
    Fine structure of the rabbit adrenal cortex and the effects of short-term ACTH administration (1979)
    Springer
    Cell & tissue research 201 (1979), S. 165-179 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Steroid release ; Rabbit ; Electron microscopy ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the rabbit adrenal cortex was investigated. The parenchymal cells display the ultrastructural features of steroid-producing cells, and also contain numerous electron-dense bodies frequently located near intercellular canaliculi, which open into the subendothelial space. Short-term ACTH-administration induced a noticeable decrease in the volume of the lipid compartment in the cells of all three cortical zones and a significant increase in the volume of dense bodies in the cells of zona fasciculata and zona reticularis. The hypothesis that these dense bodies are secretory granules is discussed in the light of biochemical evidence showing that ACTH increases the concentration of both corticosterone and cortisol in the decapsulated-enucleated adrenal homogenate and does not affect the activity of two lysosome-marker enzymes (i.e., acid phosphatase and β-glucuronidase).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235055
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  • 118
    Electronic Resource
    Electronic Resource
    Ultrastructural heterogeneity of the mesocoxal muscles of Periplaneta americana (1979)
    Springer
    Cell & tissue research 201 (1979), S. 305-314 
    Details
    ISSN: 1432-0878
    Keywords: Cockroach ; Muscle heterogeneity ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural studies have been performed upon the posterior coxal depressor muscle (136) and a coxal branch of the main depressor group (135d′) from the mesocoxa of the cockroach, Periplaneta americana. The quantitative stereometric analyses performed have shown the latter muscle to consist of a dorsal band of fibers having 25.5% mitochondria and 13.6% sarcoplasmic reticulum (SR) and T-tubules (TTS), and a ventral group of fibers with only 4.4% mitochondria and 26.6% SR/TTS. The volume fractions characteristic of the ventral fibers of muscle 135 d′ are also typical of muscle 136.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235066
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  • 119
    Electronic Resource
    Electronic Resource
    A dense-cored filamentous body in Leydig cells of the golden hamster (1979)
    Springer
    Cell & tissue research 201 (1979), S. 369-376 
    Details
    ISSN: 1432-0878
    Keywords: Leydig cells ; Filaments ; Golden hamster ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A unique cytoplasmic structure has been observed in Leydig cells of the golden hamster. It consists of a laminar core made up of electron dense material surrounded by a filamentous matrix of lower density, and is tentatively called a dense-cored filamentous body (DCFB). DCFBs vary in overall size and in configuration of the centrally disposed dense lamina. They are typically located in the vicinity of the centrosome and the Golgi complex. The body has no limiting membrane, and may be in contact with virtually every type of organelle. The DCFB is well developed in active Leydig cells, whereas it is small in the quiescent stage of the secretory cell. It is likely that the DCFB is a constant organelle in the hamster Leydig cell and may be involved in the physiological function of the Leydig cell, which remains to be specified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236997
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  • 120
    Electronic Resource
    Electronic Resource
    An ultrastructural study of macrophage-mediated resorption of calcified tissue (1979)
    Springer
    Cell & tissue research 202 (1979), S. 125-132 
    Details
    ISSN: 1432-0878
    Keywords: Macrophage ; Osteoclast ; Bone resorption ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural observations on macrophage-mediated resorption of calcified tissue of killed fetal long bones are described and correlated with increased 45Ca release into the medium. Macrophages disrupt calcified tissue extracellularly and appear to engulf large fragments of mineralized matrix. Ruffled borders, which are common features of osteoclasts at sites of resorption of bone, do not develop in macrophages. However, clear zones are seen in macrophages as well as osteoclasts. These findings provide additional evidence for non-osteoclast-mediated resorption of calcified tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239225
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  • 121
    Electronic Resource
    Electronic Resource
    Oogenesis in Campodea sp. (Diplura) (1979)
    Springer
    Cell & tissue research 202 (1979), S. 133-143 
    Details
    ISSN: 1432-0878
    Keywords: Oogenesis ; Yolk formation ; Nurse cells ; Ultrastructure ; Diplura
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The egg chamber of Campodea consists of a group of nurse cells and an oocyte, and is surrounded by a simple, markedly flattened follicular epithelium. Three types of yolk occur in the oocytes: type I appears within elements of the rough endoplasmic reticulum; type II is produced by specific complexes of endoplasmic reticulum and dictyosomes; type III is incorporated by micropinocytosis. Histochemical tests show that mature yolk spheres contain proteins and polysaccharides. The main function of the nurse cells is to synthesize RNA, but they also produce small amounts of type I yolk. Phylogenetic conclusions are drawn from this and other studies of oogenesis in apterygote insects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239226
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  • 122
    Electronic Resource
    Electronic Resource
    Ultrastructural studies on oogenesis in Symphyla (1979)
    Springer
    Cell & tissue research 202 (1979), S. 145-153 
    Details
    ISSN: 1432-0878
    Keywords: Oogenesis ; Yolk formation ; Ultrastructure ; Symphyla
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The paired ovaries of Symphyla are sac-shaped. Their interior is filled with synchronously developing oocytes surrounded by a simple follicular epithelium. Previtellogenic oocytes have spherical or oval nuclei, the latter containing a large number of small nucleoli. Part of the nuclear surface is covered by a thick “coat” made up of a granular substance of medium electron density. The “coat” is penetrated by cisternae of the smooth endoplasmic reticulum. Micropinocytosis is the principal source of yolk in Symphyla; a small amount of yolk material arises within the mitochondrial cristae. Vitellogenic oocytes are characterized by a highly active rough endoplasmic reticulum synthesizing a material, probably lipoprotein in nature, which is incorporated into lipid droplets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239227
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    The mineralization processes in Teleost fish scales (1979)
    Springer
    Cell & tissue research 202 (1979), S. 203-212 
    Details
    ISSN: 1432-0878
    Keywords: Mineralization processes ; Scales ; Teleost fish ; Matrix vesicles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In Teleost fish scales, growth and mineralization are continuous. Different mineralization processes can be distinguished. The external layer of the scale is the first to be mineralized and may be classified as the initial calcifying structure of the scale. The initial calcification loci are matrix vesicles of cellular origin always observed during the formation of this layer. This mineralization process takes place progressively, closely following the elaboration of the organic matrix in the scale periphery. The outer limiting and internal layers of the scale are developed after the external layer has been formed. A mineral substance is deposited without the mediation of matrix vesicles, but in contact with the previously mineralized external layer. This type of mineralization is called subsequential. However, the mineralization of the outer limiting layer closely follows the secretion of a collagen-free organic matrix and is thus different from the mineralization of the internal layer in which the calcification front remains remote from the collagen matrix surface and corresponds to a delayed mineralization process. The isolated calcifications (Mandl's corpuscles) which develop in the unmineralized laminae of the internal layer are mineralized in the absence of matrix vesicles and without making contact with a pre-existing calcified tissue, probably by a heterogeneous nucleation of the collagen fibrils.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232235
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    Fine structure of the rhombencephalic tela of the bullfrog, Rana catesbeiana (1979)
    Springer
    Cell & tissue research 202 (1979), S. 479-491 
    Details
    ISSN: 1432-0878
    Keywords: Ependyma ; Ultrastructure ; Posterior tela choroidea ; Rhombencephalon ; Rana catesbeiana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The posterior rhombencephalic tela choroidea of the bullfrog was examined by electron microscopy. This membrane, the pia-ependymal roof of the caudal hindbrain, contains a large central region characterized by cuboidal ependymal cells which surround sizable microscopic apertures — the interependymal pores. Ultrastructurally ependymal cells of this area are characterized by infrequent apical microvilli and cilia. They contain irregularly shaped nuclei and few cytoplasmic organelles that are largely apical in position. The most striking feature is an abundance of cytoplasmic filaments forming an extensive cytoskeleton. Laterally these cells are joined by numerous elaborate desmosomes. The majority of the ependymal cells have a basal lamina consisting of single, double, or triple laminae lying parallel to the basal plasma membrane. Several unusual specializations are seen at the margins of the interependymal pores. The ependymal cells have lateral cytoplasmic processes that form the actual border of each pore. These processes originate from the apical surface of the cell and partially enclose an elaborate network of basal lamina associated with the interependymal pores. These findings demonstrate microscopic apertures in the roof of the fourth ventricle in the bullfrog that are associated with an unusual form of supportive ependyma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220439
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    Ultrastructural changes in neurohaemal tissue of the stick insect, Carausius morosus, induced by the ionophores Br-X-537 A and A-23187 (1979)
    Springer
    Cell & tissue research 197 (1979), S. 227-234 
    Details
    ISSN: 1432-0878
    Keywords: Neurosecretory granules (Insects) ; Ionophores ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The antibiotic ionophores Br-X-537A and A-23187 alter the ultrastructure of neurohaemal tissue on the transverse nerve of the stick insect, Carausius morosus. Br-X-537A induces dramatic changes in the ultrastructural appearance of all three types of neurosecretory fibres present in the neurohaemal tissue. The neurosecretory granules become more electron-lucent and the mitochondria become more electron-opaque. The bounding membrane of the granules is frequently ruptured. A-23187, on the other hand, has no effect on two of the three types of fibres, but does produce an increase in the number of exocytotic profiles in the third. The two ionophores therefore have different effects on the same tissue. The results are discussed in the light of previous work with the use of these ionophores.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233916
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  • 126
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    Electron microscopic study of the termination of the centrifugal fibers in the goldfish olfactory bulb (1979)
    Springer
    Cell & tissue research 197 (1979), S. 257-262 
    Details
    ISSN: 1432-0878
    Keywords: Centrifugal fibers ; Olfactory bulb ; Goldfish ; Degenerating synapses ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The terminals of centrifugal fibers to the olfactory bulbs of goldfish were studied by electron microscopy after transection of the medial, lateral or entire olfactory tract. The centrifugal fibers originate in the telencephalic hemisphere, pass through both the medial and the lateral olfactory tract, and form synaptic contacts with dendrites in the granule cell layer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233918
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    In vitro differentiation of hypothalamic magnocellular neurons of guinea pigs (1979)
    Springer
    Cell & tissue research 203 (1979), S. 393-401 
    Details
    ISSN: 1432-0878
    Keywords: Guinea pig ; Hypothalamus ; Differentiation ; Organ culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of neurophysin-oxytocin and neurophysinvasopressin containing neurons of the guinea pig was studied in vitro. Supraoptic (SO) and paraventricular (PV) nuclei were explanted from guinea pig foetuses at the 40th day of gestation and cultured in Maximov slides for nearly fifty days. The cultures were observed daily under a phase-contrast microscope. Explants were fixed every five days for observation with the electron microscope. At the time of explantation, magnocellular neurons were still immature. They acquired the morphologic characteristics of mature neurons, with axosomatic synapses, after about 10 days in vitro. After 15–20 days in vitro, they contained in addition neurosecretory granules (NSG), first in the Golgi region, then also dispersed in the cytoplasm. In the oldest culture (45–50 days), signs of granulolysis were regularly found. It appears that magnocellular neurosecretory neurons are able to differentiate in vitro from a primitive state in the absence of specific stimulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233269
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    Ultrastructural development of the neurohemal organ joined to the ecdysial gland after imaginal moulting in the male isopod Sphaeroma serratum fab. (Crustacea Flabellifera) (1979)
    Springer
    Cell & tissue research 203 (1979), S. 403-414 
    Details
    ISSN: 1432-0878
    Keywords: Neurohemal organ ; Neurosecretion ; Moulting gland ; Ultrastructure ; Crustaceans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Chez Sphaeroma serratum, la mue de puberté est suivie d'une dégénérescence de l'organe Y (glands de mue). Le plexus nerveux céphalique latéral, organe neurohémal accolé à cette glande a été l'objet de la présente étude ultrastructurale. Cet organe représente un centre de stockage de neurosécrétions qui proviennent d'une part, de deux cellules autochtones (cellules plexales) situées au sein même de ce plexus, d'autre part, de cellules neurosécrétrices situées dans le “ganglion mandibulaire” (cellules de type A). Chez les individus pubères, les cellules plexales et les cellules A du ganglion sous-oesophagien synthétisent des granules de neurosécrétion dont la taille est respectivement 1550±50Å et 1570±40Å. Il a été reconnu au sein du plexus 5 catégories de terminaisons dont les granules proviendraient pour deux d'entre elles des cellules plexales et des cellules A du “ganglion mandibulaire”. Chez les animaux pubères on observe un arrêt de la synthèse des granules de neurosécrétion au sein des cellules plexales et des cellules A du “ganglion mandibulaire”. Simultanément on enregistre dans le plexus la raréfaction puis la disparition des divers types de granules. Ce processus atteint en premier les terminaisons correspondant aux cellules plexales et aux cellules A du “ganglion mandibulaire”. La dégénérescence de la glande de mue chez les mâles pourrait être en relation avec l'arrêt de synthèse de ces cellules.
    Notes: Summary The present ultrastructural study deals with the lateral cephalic nerve plexus of Sphaeroma serratum, a neurohemal organ joined to the Y organ (ecdysial gland). This plexus acts as a storage centre for neurosecretory products from two sources: the two autochtonous cells (plexus cells) within the plexus itself, and the neurosecretory cells in various parts of the central nervous system, particulary the “mandibular ganglion” (A-cells). In prepuberal animals, plexus cells and subesophageal A-cells produce neurosecretory granules of two types measuring 1550±50Å and 1570±40Å respectively. Five categories of axon terminals were distinguished in the plexus. The granules found in two of these terminal types are believed to come from the plexus cells and from the “mandibular ganglion” A-cells. Cessation of production of neurosecretory granules in these A cells and plexus cells was observed in puberal animals, in the plexus with concomitant depletion and disappearance of different granule categories. The first axon terminals affected by this process are the two categories containing granules originating in the plexus and “mandibular ganglion” A-cells. Degeneration of the ecdysial gland in male Sphaeroma serratum might be connected with the cessation of granule formation in these two types of cell.
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    URL: http://dx.doi.org/10.1007/BF00233270
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    Ultrastructure of the antennal sensilla of aphids (1979)
    Springer
    Cell & tissue research 203 (1979), S. 427-442 
    Details
    ISSN: 1432-0878
    Keywords: Aphids ; Sensilla ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An electron microscopical study was made of the coeloconic and placoid sensilla on the antennae of the aphids Aphis pomi, Macrosiphum euphorbiae, Nasonovia ribis-nigri, and Pemphigus bursarius. Scanning electron microscopy revealed some variation in morphology which may be functionally important but is more likely to reflect the evolution of these species. The placoid sensilla were shown by transmission electron microscopy to have the same basic structural pattern. Each group of two or three neurons is surrounded by two ensheathing cells. The ciliary regions of the dendrites pass through a vacuole into a cavity between an outer and an inner cuticle where they may be connected to the dendritic branches although such connections were not seen. Small pores (8 nm diameter) partially penetrate the cuticle implying that these sensilla have an olfactory function. They are suggested to be important in host selection by alate aphids. The coeloconic sensilla are poreless pegs with nonsensory cuticular projections at their tips. The distal portions of their dendrites contain densely packed microtubules and the cellular arrangement of the sensilla is similar to that of the placoid sensilla. It is suggested that they may function as thermoreceptors.
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    URL: http://dx.doi.org/10.1007/BF00233272
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    The osteoclast-endothelium interface during bone resorption in the femurs of young rabbits (1979)
    Springer
    Cell & tissue research 203 (1979), S. 487-492 
    Details
    ISSN: 1432-0878
    Keywords: Osteoclasts ; Endothelium ; Bone resorption ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphological relationship between the osteoclasts at the endosteal surface of two-week-old rabbit femurs and the endothelium of vascular channels of the bone marrow was examined. Light microscopy revealed that 85% of the osteoclasts make direct contact with the endothelial cells. The ultrastructure of this osteoclast-endothelium interface shows that the osteoclast has specialized processes which reach out towards the endothelial cells coming into close proximity with them. On rare occasions, specialized junctions between these processes and the endothelial cells are noted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233276
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    Ultrastructural evidence for disuse atrophy in insect skeletal muscle (1979)
    Springer
    Cell & tissue research 203 (1979), S. 503-506 
    Details
    ISSN: 1432-0878
    Keywords: Muscle ; Disuse atrophy ; Insects ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The changes which occur in the ultrastructure of the mesothoracic retractor unguis muscle of the cockroach Periplaneta americana as a result of disuse are described. Breakdown of myofibrils, sarcoplasmic reticulum, and mitochondria are all marked, this degeneration only being apparent 9 weeks after the operation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233279
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    A new and unusual type of transport vesicle (1979)
    Springer
    Cell & tissue research 203 (1979), S. 499-502 
    Details
    ISSN: 1432-0878
    Keywords: Special vesicles ; Membrane transport ; Gastropoda ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The adventitial cells surrounding the spermatheca of the reproductive system of Sonorella santaritana (Mollusca: Gastropoda) appear to have an unusual system of vesicles. Electron micrographs of the membranes forming these vesicles show that they have multiple openings to the cell's exterior and that each opening has a “pore complex”. In addition, secondary vesicles appear to be generated by the primary vesicles. Evidence is presented suggesting that these vesicles represent a previously unreported membrane transport system.
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    URL: http://dx.doi.org/10.1007/BF00233278
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    Electron microscopic immunocytochemical demonstration of separate vasotocinergic and mesotocinergic nerve fibres in the median eminence of the frog hypophysis (1979)
    Springer
    Cell & tissue research 204 (1979), S. 29-36 
    Details
    ISSN: 1432-0878
    Keywords: Median eminence ; Hypophysis ; Rana temporaria ; Vasotocinergic fibres ; Mesotocinergic fibres ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary With the use of the unlabelled antibody peroxidase-antiperoxidase complex (PAP) technique at the electron microscopic level, it was shown that both the internal and the external regions of the median eminence of the frog contain separate vasotocinergic and mesotocinergic nerve fibres. This observation confirms the results of previous immunocytochemical studies at the light microscopic level. The mean size of the neurohypophysial hormone-containing granules in the external region of the median eminence is significantly smaller than that of the neurohypophysial hormone-containing granules in the internal region of the median eminence. No significant difference could be found between the mean granule size of the vasotocinergic and mesotocinergic fibres of either the internal or the external region of the frog median eminence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235162
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    The pineal gland of the gerbil, Meriones unguiculatus (1979)
    Springer
    Cell & tissue research 204 (1979), S. 95-109 
    Details
    ISSN: 1432-0878
    Keywords: Pineal gland ; Gerbil ; Pinealocytes ; Morphometric analysis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By means of morphometric analytical procedures, a diurnal rhythm in the cellular volume of gerbil pinealocytes was determined. This rhythm has been attributed primarily to a change in the cytoplasmic volume of the pinealocytes which is low during the daylight hours and increases to reach a peak during the middle of the dark period. At the ultrastructural level, six cytoplasmic components of the pinealocytes were found to exhibit a rhythm: free cytoplasm, smooth endoplasmic reticulum (SER), rough endoplasmic reticulum (RER) and ribosomes, secretory vesicles, microtubules, and mitochondria. The presumptive secretory vesicles and the microtubules reached a peak in volume one hour before lights-off. It is suggested that lights-on and lights-off both signal a decrease in size and/or number of the secretory vesicles. The SER and RER/ribosomes reached their peak volume one hour after lights-off which is interpreted as indicating a peak in indoleamine synthesis and protein synthesis, respectively. The volume of free cytoplasm exhibits two peaks; one occurs one hour before lights-off while the second peak occurs in the middle of the dark phase. It is suggested that, although part of the secretory product of the pinealocyte may be present in dense-cored vesicles, other locations could include the free cytoplasm and clear secretory vesicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235167
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    Synaptic connections of the Nervus connectivus in the frontal ganglion of Periplaneta americana L. (Insecta) (1979)
    Springer
    Cell & tissue research 204 (1979), S. 155-159 
    Details
    ISSN: 1432-0878
    Keywords: Nervus connectivus ; Periplaneta ; Synaptic contacts ; Iontophoresis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The course of the Nervus connectivus (N.c.), its branches, and synaptic connections within the frontal ganglion (FG) were investigated electron microscopically after cobalt iontophoresis of the N.c. The subsequent treatment of ultrathin sections with Timm's method was found to be very suitable for identifying the smallest branches. In the neuropil, fibers of the N.c. form Gray-I-type synapses, but also dyads are abundant, whereby the N.c. fibers occur exclusively in postsynaptic position with neurosecretory fibers. The possible role of these relationships is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235172
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    Neurite complexes with Merkel cells in larval tentacles of Xenopus laevis (1979)
    Springer
    Cell & tissue research 204 (1979), S. 233-241 
    Details
    ISSN: 1432-0878
    Keywords: Merkel cell ; Sensory receptors ; Epidermis ; Frog tadpoles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopy of larval tentacles of Xenopus laevis tadpoles revealed that they are richly innervated structures containing a high concentration of neurite complexes with epidermal Merkel cells. Myelinated sensory nerve fibres supplying each tentacle are abundant. Prior to penetrating the epidermis, they gradually shed their myelin sheaths and Schwann-cell coverings, and subsequently end as naked axon terminals within the epidermis. Many of these intra-epidermal neurites terminate in intimate synaptic contact with granulated Merkel cells. Groups of dense-cored vesicles characterize the Merkel cell, while clusters of clear synaptic vesicles occupy the adjacent sensory nerve terminals. At sites of synaptic contact, the two cells often exhibit an increased thickening of their apposing membranes. Such Merkel cell — sensory neurite complexes occur as isolated units and are profusely scattered throughout the extent of each tentacle. Their ultrastructure is, in most respects, similar to that described previously in specialized regions of other vertebrate and amphibian species. It is suggested that they represent the morphological basis for tactile sensitivity and impart a mechanoreceptive function to the larval tentacle prior to metamorphosis. The larval tentacle in this anuran species may represent a new and convenient research model for future developmental and experimental studies of trophic interactions between sensory nerve fibres and Merkel cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234635
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    The hypothalamo-hypophysial system of the lamprey, Lampetra fluviatilis L. (1979)
    Springer
    Cell & tissue research 204 (1979), S. 319-331 
    Details
    ISSN: 1432-0878
    Keywords: Median eminence ; Lamprey ; Regulation of pars distalis ; Fluorescence microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The proximal neurosecretory contact region (PNCR) of the lamprey, a homologue of the median eminence of tetrapods, was studied by light, fluorescence and electron microscopy. Paraldehyde fuchsin-positive neurosecretory fibers are seen mainly in the central part of the rostral subdivision of the PNCR. The Falck-Hillarp technique reveals a weak, mainly diffuse yellow-green fluorescence in the PNCR. The ultrastructure of the tanycyte layer of the PNCR is very similar to that in the neurohypophysis of the same species, although the funnel-shaped protrusions of the third ventricle in the rostral part of the PNCR are more frequent than in the neurohypophysis. Peptidergic A1 and A2 neurosecretory fibers are characterized by neurosecretory granules of 120– 200 nm and 100–150 nm in diameter, respectively. Monoaminergic B type fibers contain granules 80–100 nm in diameter. Neurosecretory terminals and the vascular endfeet of tanycytes make contact with the basement membrane of the avascular connective tissue layer separating the PNCR from the hypophysial pars distalis. It is suggested that both peptide and monoamine neurohormones diffuse through the thick connective tissue septa into the underlying blood vessels which supply the pars distalis and thus affect the function of its glandular cells.
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    URL: http://dx.doi.org/10.1007/BF00234643
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    Ultrastructure of pinealocytes of the cotton rat, Sigmodon hispidus (1979)
    Springer
    Cell & tissue research 204 (1979), S. 407-416 
    Details
    ISSN: 1432-0878
    Keywords: Pineal gland ; Ultrastructure ; Cotton rat (Sigmodon hispidus)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Fine structural features of pinealocytes of cotton rats (Sigmodon hispidus) were examined. Golgi complexes, mitochondria, endoplasmic reticulum and polysomes are usual organelles seen in the perikaryonal cytoplasm of pinealocytes. Many non-granulated vesicles (40 to 80 nm in diameter) and a few granulated vesicles (about 100 nm in diameter) are associated with the Golgi cisternae. Occasionally, the cisternae contain granular materials. The perikaryonal cytoplasm of pinealocytes is characterized by the presence of inclusion bodies. These bodies are usually round in shape, not bounded by a limiting membrane and composed of fine granular or filamentous materials of high electron-opacity, which are similar in appearance to the substance seen in the nucleolonema. Pinealocyte processes, filled with abundant non-granulated vesicles and some granulated vesicles, are mainly found within the parenchyma and occasionally in perivascular spaces.
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    URL: http://dx.doi.org/10.1007/BF00233652
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    Ultrastructure of the swim bladder of the goldfish, Carassius auratus (1979)
    Springer
    Cell & tissue research 198 (1979), S. 105-117 
    Details
    ISSN: 1432-0878
    Keywords: Swim bladder ; Physostome ; Cyprinid ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The swim bladder of the cyprinid Carassius auratus (goldfish) is a two-chambered organ connected to the esophagus by a pneumatic duct. The anterior chamber is lined by a single type of squamous epithelial cell. Two types of epithelial cells are present in the posterior chamber. Flattened cells with differences in the electron density of the cytoplasm line most of the chamber. Darker cells generally contain large amounts of glycogen. Cuboidal epithelial cells also occur in the posterior chamber. A glandular layer external to the muscularis in the posterior chamber is composed of large cells containing little glycogen, an extensive Golgi apparatus, and numerous mitochondria with single large granules. Capillaries and nerves are present in large numbers in this layer. Blood vessels form micro-retia mirabilia in the submuscular layer external to the glandular layer. Vessels are of two distinct types with wide lumina and flattened endothelium characterizing the venous vessels. Arterial vessels have smaller lumina, thick endothelial cells with prominent pinocytotic vesicles, and surrounding pericytes. Collagen is present in three forms in this swim bladder — large tactoids in the tunica externa of the anterior chamber, smaller tactoids in the lamina propria of the posterior chamber, and small fibrils in all other areas.
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    URL: http://dx.doi.org/10.1007/BF00234838
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    Morphological characteristics of the spermatogonial stem cells in man (1979)
    Springer
    Cell & tissue research 198 (1979), S. 191-199 
    Details
    ISSN: 1432-0878
    Keywords: Spermatogonia ; Man ; Stem cells ; Morphology ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present investigation is concerned with establishing morphological criteria of spermatogonial stem cells in man. Testicular biopsies from patients having undergone semicastration for malignant tumors and radioand chemotherapy for one year following the operation were studied light and electron microscopically. Those spermatogonial types that survived the treatment were regarded as stem cells in view of the fact that the stem cells, in contrast to the more differentiated spermatogonia, are radiation resistant and less sensitive to various noxious agents. In 7 out of 28 cases examined, a small number of spermatogonia was found adjacent to the basement membrane. The majority of these cells show the characteristic features of pale type A spermatogonia, while a few cells may represent variants of this cell type. The dark type A spermatogonia are almost completely eliminated from the seminiferous tubules. A concept is proposed that the stem cells of the human testis may be derived from the pale type A spermatogonia or the variants of this cell type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232003
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    Control of the pars intermedia of the lizard, Anolis carolinensis (1979)
    Springer
    Cell & tissue research 198 (1979), S. 411-426 
    Details
    ISSN: 1432-0878
    Keywords: Intermediate lobe ; Hypophysis ; Ultrastructure ; Colour change ; Control mechanisms ; Anolis carolinensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the intermediate lobe of the hypophysis was studied in Anolis carolinensis with the use of a threefold aldehyde fixative. Lizards with a brown skin were selected. The possibility of two types of secretory cells is discussed; neither cell type is innervated. Type I cells are rarely found and contain dense granules approximately 0.3 μm in diameter; Type II cells vary widely in secretory activity. Most of the Type II cells contain a large number of dense secretory granules (up to about 1.3 μm in diameter) almost filling the cytoplasm. Rough endoplasmic reticulum (RER), Golgi apparatus and mitochondria are poorly developed. Only some of these cells show signs suggesting a high secretory activity, namely a well developed RER, Golgi apparatus and numerous mitochondria. In these cells the RER sometimes forms large intracisternal droplets (up to 7 μm in diameter). Two of the animals exhibited a more uniform, high secretory activity. Large (about 2 μm in diameter), pale vacuoles, probably of extracellular character, were found mostly in the vicinity of the perivascular septum. Their role in the release of MSH is discussed. The present data, which are discussed with reference to earlier findings (Forbes, 1972), form the morphological basis for an experimental study on regulation of MSH release (Larsson et al., 1979).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234186
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  • 142
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    Formation of sarcomeres in the embryonic heart of the lobster (1979)
    Springer
    Cell & tissue research 198 (1979), S. 477-486 
    Details
    ISSN: 1432-0878
    Keywords: Embryonic heart ; Myogenesis ; Sarcomere ; Crustacea (Homarus americanus) ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cardiomyoblasts in the myocardium of embryonic lobsters at 3–4 weeks and 6 months of development were examined with the transmission electron microscope in order to describe the events in the formation of sarcomeres in a neurogenic cardiac system. Thick and thin myofilaments appear first in the cell periphery near the sarcolemma. They align in parallel in a sequential fashion to form consecutive sarcomeric units. Well-defined A and I bands appear before any semblance of a Z line is present. The initial sarcomere is anchored to the sarcolemma by the insertion of thin myofilaments into a region of electron dense material associated intimately with the sarcolemma. Myofibrils grow outward in several planes away from the electron-dense regions of membrane that serve as focal points for myofibril formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234192
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  • 143
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    Quantitative comparison of low- and high-output neuromuscular synapses from a motoneuron of the lobster (Homarus americanus) (1979)
    Springer
    Cell & tissue research 198 (1979), S. 455-463 
    Details
    ISSN: 1432-0878
    Keywords: Neuromuscular synapses ; Presynaptic density ; Ultrastructure ; Serial sections ; Crustaceans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Representative examples of lowand high-output neuromuscular synapses between motoneuron and distal accessory flexor muscle of the lobster were selected on the basis of their mean quantal content, and subsequently analysed by serial section electron microscopy. The high-output terminal has twice as many synapses as the low-output terminal. However, since the mean surface area of synapses is significantly smaller in the high-output terminal than in the low-output one, the total synaptic surface area between the two types of terminals is similar. Also, though the high-output terminal possesses a greater number of presynaptic dense bodies than its low-output counterpart, the mean number per synapse is similar for the two terminals. The terminals, however, differ significantly in the size of their dense bodies. Thus both the mean and total surface area of these bodies is greater in the high-output terminal than in the low-output one. Moreover, the mean ratio of dense body area to synaptic area is significantly greater for the high-output terminal than for its low-output counterpart. This difference in dense body area parallels the difference in quantal content of synaptic transmission between the lowand high-output terminals and supports the hypothesis that presynaptic densities represent the ultrastructural correlates of transmitter mobilization and/or release.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234190
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  • 144
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    The effect of L-DOPA on the ultrastructure of the adenohypophysis of the Chinese quail, Excalfactoria chinensis (1979)
    Springer
    Cell & tissue research 198 (1979), S. 521-526 
    Details
    ISSN: 1432-0878
    Keywords: Adenohypophysis ; Electron microscopy ; L-DOPA ; Lysosomes ; Chinese quail, Excalfactoria chinensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intraperitoneally injected L-DOPA was found to stimulate strongly the lysosomal system of all of the cell types of the adenohypophysis. We suggest that this amine may play a role in the regulation of the secretory activity of the gland by mediating the lysosomal activity, this role being of variable importance according to the fluctuations in hormonal activity. Ultrastructural changes occur in some cell types following injection of L-DOPA. The question as to whether these changes are induced directly by L-DOPA or via the monoaminergic system of the hypothalamus and its hypophysiotropic hormones is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234195
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  • 145
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    Control of the pars intermedia of the lizard, Anolis carolinensis (1979)
    Springer
    Cell & tissue research 199 (1979), S. 1-23 
    Details
    ISSN: 1432-0878
    Keywords: Neuro-intermediate lobe ; Hypophysis ; Disconnection ; Ultrastructure ; Colour change ; Control mechanisms ; Anolis carolinensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Morphological changes in the disconnected neuro-intermediate lobe were studied in the lizard, Anolis carolinensis from the 2nd to the 14th post-operative day using a threefold aldehyde fixative (Rodríguez, 1969). Two phases of colour change capacity were exhibited: Phase I started immediately after the transection, lasted for 6 days (mean) and was characterised by an excessive MSH release (brown skin). This phase proceeded gradually into Phase II, designated by an interruption of the MSH release (green skin). The degenerative processes and final elimination of neurons in the disconnected neural lobe propagate in a rostro-caudal direction from the transected area. The aminergic fibres (Type II) disappear within 2 days postoperatively, whereas the degeneration continues for more than 10 days in the peptidergic fibres (Type III, IV and V). The glia cells (ependyma and pituicytes) serve as very active macrophages, engulfing fragments of axons already affected by autolysis and transferring them into glial lysosomes. No apparent morphological changes occur in the shift from Phase I to II. The great majority of the secretory cells of the intermediate lobe are not affected by degenerative processes and appear to be markedly activated by the stalk transection. They exhibit numerous mitochondria, well-developed Golgi complexes forming numerous Golgi vesicles and extensive parallel cisternae of the rough endoplasmic reticulum, sometimes forming large intracisternal droplets (7 μm in diameter). Numerous pale vacuoles are seen, especially toward the intact capillaries, suggesting their coupling to the MSH release by extension of the active membrane area toward the perivascular septum. The number of these vacuoles is very markedly reduced in Phase II (no release), whereas the formation of new granules seems to proceed in early stages. The interruption of the MSH release implies a successive refilling of gradually growing secretory granules and a concomitant reduction in the development of the synthetic apparatus. Mechanisms probably involved in the control of the synthesis and release of MSH are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237724
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  • 146
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    Ultrastructural studies on erythropoiesis in the avian thymus (1979)
    Springer
    Cell & tissue research 199 (1979), S. 37-61 
    Details
    ISSN: 1432-0878
    Keywords: Avian thymus ; Ultrastructure ; Erythropoiesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Thymus lobes from three species of birds, Quelea quelea, Passer domesticus and Sturnus vulgaris, have been examined ultrastructurally. The component cell types are compared with their counterparts in mammalian thymus glands, and found to be similar. Greater differences exist between small, intermediate and enlarged lobes of one species than exist between species. Developing erythroid cells are present in most enlarging and some enlarged glands. They appear to be developing at the expense of lymphoid cells in some birds. The origin of these cells is discussed. Cells that are possible candidates for the production of some thymic hormones are also described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237726
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  • 147
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    An ultrastructural and cytochemical study of the interaction between latex particles and the haemocytes of the wax moth Galleria mellonella in vitro (1979)
    Springer
    Cell & tissue research 199 (1979), S. 127-137 
    Details
    ISSN: 1432-0878
    Keywords: Haemocytes ; Phagocytosis ; Lysosomes ; Acid phosphatase ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The plasmatocytes are the major phagocytic blood-cell type in the haemolymph of the wax-moth, Galleria mellonella. In the present study, these cells were allowed to attach to tissue culture dishes for 1 h, rinsed and then incubated with latex beads for up to 72 h. These cells were then fixed for routine transmission electron microscopy and acid phosphatase cytochemistry. Intracellular latex particles were found in tight, ill-defined phagosomes, which were often clearly associated with the Golgi complexes of the plasmatocytes. Fusion of both primary lysosomes and multivesicular bodies with the phagosomes occasionally occurred and this resulted in the accumulation of an acid phosphatase positive reaction product around the test particles. Subsequent experiments showed that this acid phosphatase activity was mainly associated with the primary lysosomes. The results of the lysosome/latex interactions are compared with those obtained from similar studies on the digestive mechanisms in other phagocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237732
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  • 148
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    Reformation of gap and tight junctions in regenerating liver after cholestasis (1979)
    Springer
    Cell & tissue research 199 (1979), S. 257-270 
    Details
    ISSN: 1432-0878
    Keywords: Liver ; Bile duct ligation ; Tight junctions ; Gap junctions ; Ultrastructure ; Freeze-fracturing ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Morphometric analysis of the alterations in interhepatocyte junctions induced by bile duct ligation revealed that after 48 h, during which time the serum bilirubin increased 6 to 8 fold, the membrane area occupied by gap junctions on the apico-lateral and medio-lateral sides decreased from 3.6% in controls to 0.02% in the ligated group. The strands of the zonulae occludentes were reduced in number and showed increased discontinuities. Within 45 min of recanalization of the common bile duct, clusters of particles appeared within and adjacent to the tight junctional areas or in the lateral hepatocyte membrane. Subsequently, the particle aggregations localized in the apico-lateral membrane areas increased in number and size becoming finally indistinguishable from those of controls within 96 h after the onset of recanalization. The zonulae occludentes also rearranged and reestablished their original structure during this period. The serum bilirubin fell to normal within 24 h of recanalization. It is concluded that metabolic and ultrastructural restitution associated with the recanalization of the ligated bile duct have no strict temporal correlation to one another. These studies provide further evidence that alterations in gap and tight junctions induced by pathological processes, e.g. during bile duct ligation, are completely reversible when regeneration occurs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236137
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  • 149
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    Marginal bundles of axoplasmic microtubules at nodes of Ranvier within muscle (1979)
    Springer
    Cell & tissue research 199 (1979), S. 281-288 
    Details
    ISSN: 1432-0878
    Keywords: Annular microtubules ; Nodes of Ranvier ; Nerve ; Axon ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using a special albumin technique, nodes of Ranvier have been examined within frog skeletal muscle, sciatic nerve and rat and frog cerebrum. Initial segments have been examined in cerebrum of frog and rat. Microtubules usually run longitudinally through these regions, but within the bare area of the intramuscular node of Ranvier, annular or helical bundles of microtubules run in a marginal band at right angles to the more centrally placed longitudinal microtubules. These nodal bare areas show a pronounced convexity and it is suggested that the annular microtubules serve to maintain this convexity during muscle contraction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236139
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  • 150
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    T-tubes in cultured mammalian myocardial cells (1979)
    Springer
    Cell & tissue research 203 (1979), S. 173-180 
    Details
    ISSN: 1432-0878
    Keywords: Tissue culture ; Cardiac myocyte ; Heart ; T-tubes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary T-tubes are among the last structural elements of the mammalian myocyte to develop in vivo. We were able to identify T-tubes in early cultures of neonatal rat myocytes. Ventricles were excised from 3- to 4-day-old neonatal rats, incubated overnight in cold trypsin, and treated with sequential changes of collagenase-hyaluronidase. Fractions of cells isolated in this manner were pooled and cultured in plastic petri dishes. In cells prepared for transmission electron microscopy, T-tubes were observed at the cell periphery of cultured myocytes, but were more difficult to identify as the cultures aged and became overgrown by fibroblasts. T-tubes were identified by virtue of their continuity with the sarcolemma, their relatively large diameter, and their regular entry at the level of the Z line. Even at optimal culture ages, T-tubes were not present in every myocyte. At the times T-tubes could be located, myocytes were beating and had begun to establish intercalated discs and gap junctions. The de novo formation of T-tubes in cultured myocytes of neonatal rat heart reflects a duplication of in vivo differentiation by the cultured myocyte. The appropriateness of cultured myocytes in the study of the development and physiology of the heart is emphasized by the in vitro formation of T-tubes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237231
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  • 151
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    Granule secretion by the luteal cell of the sheep: The fate of the granule membrane (1979)
    Springer
    Cell & tissue research 197 (1979), S. 413-419 
    Details
    ISSN: 1432-0878
    Keywords: Luteal cells ; Secretory granules ; Sheep ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the corpus luteum of the sheep has been examined at the mid-stage of the estrous cycle when progesterone secretion is active. Secretory granules are associated with the secretion of this hormone, and the evidence indicates that the granule membrane becomes incorporated into the plasma membrane during exocytosis. Further evidence of this process has been obtained from studies on the uptake of horseradish peroxidase by the luteal cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233566
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  • 152
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    The differentiation of monocytes into macrophages, epithelioid cells, and multinucleated giant cells in subcutaneous granulomas (1979)
    Springer
    Cell & tissue research 197 (1979), S. 355-378 
    Details
    ISSN: 1432-0878
    Keywords: Monocytes ; Macrophages ; Epithelioid cells ; Multinucleated giant cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphological changes occurring in monocytes during their differentiation into macrophages, epithelioid cells, Langhans-type giant cells, and foreign-body-type giant cells were investigated in foreign-body granulomas induced by subcutaneous implantation of pieces of Melinex plastic. Analysis based on Adams's (1974) criteria for discrimination between the several types of cell of the monocyte line, showed that each type has a characteristic type of granule. Primary and secondary granules, numerous in the Golgi area of monocytes were generally found close to the cell membrane and decreased in number in maturing macrophages. This was accompanied by an increase in the number of microtubules. Mature macrophages show numerous characteristic macrophage granules, which are round (average diameter: 280 nm) and have a halo between the limiting membrane and granular matrix. Mature epithelioid cells have characteristic epithelioid cell granules, and multinucleated giant cells a heterogeneous population of granules. Fusing macrophages generally have their Golgi areas facing each other, and also show a reduced thickness of the cell coat. The morphology of the multinucleated giant cell is closely related to the number of nuclei present. In Langhans-type giant cells, which generally have two to ten nuclei, a giant centrosphere with numerous aggregated centrioles is found. In transition forms between Langhans-type and foreign-body-type giant cells, which generally contain 10–30 nuclei, the centrioles show less aggregation. In the foreign-body-type giant cells, which generally have more than 30 nuclei, centrioles are virtually absent and never aggregated. These differences between the Langhans-type giant cells, the foreign-body-type giant cells, and the transition forms, support our previous finding that Langhans-type giant cells are the precursors of foreign-body-type giant cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233563
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  • 153
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    The androgenic effect on the fine structure of the harderian gland in the male hamster (1979)
    Springer
    Cell & tissue research 198 (1979), S. 119-127 
    Details
    ISSN: 1432-0878
    Keywords: Male hamster ; Harderian gland ; Castration ; Sexual dimorphism ; Porphyrin ; Testosterone ; Tubular clusters ; Membranous structures ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A sexual dimorphism of the hamster Harderian gland at the ultrastructural level has been reported. The effect of testosterone on the fine structure of the gland from castrated male golden hamsters is reported here. Harderian glands from the following three groups of animals were examined at regular intervals up to 60 days after castration: (1) castrated; (2) castratedsham-injected, receiving 0.1 ml sesame oil per day; (3) castrated-testosterone injected, receiving 2mg testosterone propionate in 0.1 ml sesame oil per day. In groups 1 and 2, clusters of cylindrical tubules, typical of the male gland, decreased in number and disappeared almost completely 2 weeks after castration. Membranous structures, typical of the female gland, prevailed in these two groups throughout the remaining period of experiment. On the other hand, these changes were prevented in the group of castrated animals maintained on testosterone propionate. It is concluded that castration modified the ultrastructure of the male hamster Harderian gland toward the female type and that daily administration of testosterone propionate prevented this change.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234839
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  • 154
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    Vacuolated neurons in the hypogastric ganglion of the rat (1979)
    Springer
    Cell & tissue research 199 (1979), S. 373-386 
    Details
    ISSN: 1432-0878
    Keywords: Hypogastric ganglion (rat) ; Vacuolated neurons ; Catecholamine fluorophore ; Ultrastructure ; Testosterone ; Castration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The vacuolated neurons (VN) of the main hypogastric ganglion of the male rat were studied using the formaldehyde-induced fluorescence (FIF) method for the histochemical demonstration of catecholamines. Microspectrofluorimetry was performed to identify the fluorophores and to quantify the FIF. The thiocholine method (Koelle-Gomori) was used to demonstrate acetylcholinesterase activity. The fine structure of the VN was studied using glutaraldehyde/OsO4 fixation. (1) In the untreated adult male rat VN represent only a small population of the total number of hypogastric neurons (0.8–1.2%). The vacuoles are similar to those of the VN from the corresponding female ganglion. (2) The VN are considered to be adrenergic due to the nature of their fluorophore, indicating a primary catecholamine. (3) The first VN appear in the hypogastric ganglia at the age of 7 weeks. After testosterone administration to young rats, VN are found at the age of 4 weeks. (4) The basic fine structure of the VN is similar to that of other ordinary neurons of the hypogastric ganglia. (5) The content of the vacuoles could not be identified. (6) Indications of degeneration were not observed in the VN. (7) The VN are interpreted as being a functional stage of the “short” adrenergic neurons, which are under the control of steroid hormones. (8) Fifteen months after castration, no VN could be found in the hypogastric ganglia, while their number was normal in the corresponding control animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236076
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    The filum terminale of the frog spinal cord (1979)
    Springer
    Cell & tissue research 199 (1979), S. 519-528 
    Details
    ISSN: 1432-0878
    Keywords: Filum terminale ; Spinal cord ; Glial cells ; Ultrastructure ; Frog (Rana pipiens)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The filum terminale, or terminal portion of the spinal cord, was studied in normal adult frogs (Rana pipiens) by means of light and electron microscopy. Astroglial cells are the predominant elements in this region. The rostral portion of the filum terminale consists mainly of (1) a peripheral dense ring of myelinated and some unmyelinated nerve fibers, and processes of astrocytes terminating at the subpial space; (2) an intermediate zone, in which astrocytes are the main cellular elements in addition to a few degenerated neurons; and (3) a central region where the central canal is lined by dark and light ependymal cells. In the caudal portion of the filum terminale, the amount of neuropil is greatly reduced. This region is formed mainly by astrocytic glial cells and very few neuronal elements. The central canal in the caudal portion is located ventrally and contains a lining consisting almost exclusively of dark ependymal cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236087
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  • 156
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    Cytological changes in the pars distalis of the female rat hypophysis grafted under the kidney capsule (1979)
    Springer
    Cell & tissue research 199 (1979), S. 539-543 
    Details
    ISSN: 1432-0878
    Keywords: Pars distalis ; Graft ; Ultrastructure ; Prolactin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intact female rats received transplants of two hypophysial partes distales under the kidney capsule. The plasma levels of prolactin were determined, and the ultrastructure of the grafted gland was studied 15, 45 and 90 days after the operation. Although prolactin levels in the three experimental groups were significantly higher than those in control rats, a decrease in prolactin level was detected in the 45-day samples. Parallel ultrastructural changes suggest that between the 45th and 90th postoperative day a process is initiated leading to hyperplasia and hypertrophy of prolactotrophs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236089
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  • 157
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    Studies on fish scale formation and resorption. I. Fine structure and calcification of the scales in Fundulus heteroclitus (Atheriniformes: Cyprinodontidae)Contribution No. 220, Belle W. Baruch Institute of Marine Biology and Coastal Research, University of South Carolina, Columbia, South Carolina 29208. (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 49-65 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fine structure of the scales of Fundulus heteroclitus was examined by scanning and transmission electron microscopy. The concentric ridges of the scale surface were characterized by the presence of minute, highly calcified, denticles or tooth-like processes. Needle-shaped crystals of hydrox-yapatite were precipitated not only in the osseous layer but in the intimate lamellae of the fibrillary plate except in portions just below the grooves. The calcification of the osseous layer was observed to proceed by filling the matrix with patches of crystals. The fibrillary plate appeared to calcify by invasion of crystals from the upper calcified zone into spaces between collagen fibers.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/jmor.1051590105
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    Ultrastructural features of the retina and optic nerve of Strombus luhuanus, a marine gastropod (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 89-115 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The retina and optic nerve of Strombus luhuanus were examined by transmission electron microscopy in order to provide an ultrastructural basis for their electrophysiological responses, described elsewhere. The retina exhibits a distinct rhabdomeric layer and layers of cell nuclei and neuropile. These layers are comprised predominantly of three cell types that can be readily distinguished on the basis of their shape, their nuclei and cytoplasmic inclusions such as vesicles and filaments. One type of cell, apparently a photoreceptor that depolarizes in response to photic stimulation, possesses a long distal segment with microvilli; such distal segments comprise the bulk of the rhabdomeric layer. A second cell type, which appears to be supportive in function, contains a bundle of tightly packed tonofilaments that extend across the retina from the capsule to the vitreous body; this cell is quite narrow except in the region near the rhabdomeric layer, where it is expanded and wraps around the other cell types. A third type of cell possesses many short microvilli that project from its apical end into the rhabdomeric layer; it may be a second type of photoreceptor or another type of neuron. The retina also contains bundles of cilia that appear to project from a possible fourth type of cell. The layer of neuropile contains numerous processes that exhibit a variety of vesicle types and structures generally associated with synapses; these appear to play a role in mediating inhibitory and excitatory interactions between the retinal neurons. The optic nerve exhibits two populations of fiber distinguishable on the basis of mean diameter. Fibers in these two populations apparently yield “on” and “off” discharges in response to photic stimulation of the eye.
    Additional Material: 29 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051590108
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    Mandibular function in Galago crassicaudatus and Macaca fascicularis: An in vivo approach to Stress Analysis of the mandibleThis investigation was supported by the following: NIH Research Career Development Award (DE 00027), NIH Research Grant (DE 4531) and a NSF Research Grant (BNS 76-11924). (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 253-296 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Single-element and/or rosette strain gages were bonded to mandibular cortical bone in Galago crassicaudatus and Macaca fascicularis. Five galago and eleven macaque bone strain experiments were performed and analyzed. In vivo bone strain was recorded from the lateral surface of the mandibular corpus below the postcanine tooth row during transducer biting and during mastication and ingestion of food objects.In macaques and galagos, the mandibular corpus on the balancing side is primarily bent in the sagittal plane during mastication and is both twisted about its long axis and bent in the sagittal plane during transducer biting. On the working side, it is primarily twisted about its long axis and directly sheared perpendicular to its long axis, and portions of it are bent in the sagittal plane during mastication and molar transducer biting. In macaques, the mandibular corpus on each side is primarily bent in the sagittal plane and twisted during incisal transducer biting and ingestion of food objects, and it is transversely bent and slightly twisted during jaw opening. Since galagos usually refused to bite the transducer or food objects with their incisors, an adequate characterization of mandibular stress patterns during these behaviors was not possible. In galagos the mandibular corpus experiences very little transverse bending stress during jaw opening, perhaps in part due to its unfused mandibular symphysis.Marked differences in the patterns of mandibular bone strain were present between galagos and macaques during the masticatory power stroke and during transducer biting. Galagos consistently had much more strain on the working side of the mandibular corpus than on the balancing side. These experiments support the hypothesis that galagos, in contrast to macaques, employ a larger amount of working-side muscle force relative to the balancing-side muscle force during unilateral biting and mastication, and that the fused mandibular symphysis is an adaption to use a maximal amount of balancing-side muscle force during unilateral biting and mastication.These experiments also demonstrate the effects that rosette position, bite force magnitudes, and types of food eaten have on recorded mandibular strain patterns.
    Additional Material: 27 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051590208
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    Ultrastructure of the accessory glands of the Mediterranean flour mothAnagasta kuehniella (Zeller) (Lepidoptera: Pyralidae).Supported in part by U.S. Energy Research and Development Administration Contract P7603214. (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 355-391 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Five regions are recognized in the accessory glands of the Mediterranean flour moth, Anagasta kuehniella (Zeller), on the basis of cellular morphology and aggregates of secretory material in the lumen. Some variation is found in each of the posterior four regions, especially the third one. In the most anterior region (region 1) the epithelium is composed of a single type of cell, while in each of the other regions there are two classes of cells. The cells of region 1 and one class in each of the other four regions are fairly typical exocrine cells with extensive rough endoplasmic reticula. Secretion is primarily via Golgi-derived vesicles. Apocrine secretion in the form of sloughing off of the apical cytoplasm probably also occurs in all regions but is most prominent in the posterior two regions. One class of cells is very similar in morphology in each of the posterior four regions though their secretory products form characteristic aggregates in the lumen. The second class of cells (foliate cells) occurring in the posterior four segments is most notably characterized by elongate apical projections that extend out into the lumen. The apical projections contain large quantities of glycogen, some microtubules, and, in some cases, many minute mitochondria. The membrane content of the projections is also very high. In the anterior regions, the membranes are mostly fused in pairs and typically form multilayered whorls. Fusion and whorl formation decrease in the posterior regions. The cytoplasm of the foliate cells has a high organelle content including many lysosomes and mitochondria. The latter exhibit considerable polymorphism, with particular forms occurring in the different regions of the glands. The apical projections of the foliate cells are detached during copulation, presumably as the result of nervous stimulation, and become a part of the ejaculate. Replenishment of all secretory material, including the apical projections, occurs after copulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051590306
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  • 161
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    Partial regeneration of the above-elbow amputated rat forelimb. II. Electrical and mechanical facilitationSupported by the Veterans Administration Medical Research Program Project Number 7004-04 and a Medical Investigatorship Award to P.P. (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 439-451 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This investigation was undertaken to examine the observations of Becker ('72) pertaining to the electrical facilitation of partial limb regenerative responses by means of Ag-Pt wire couples applied to the limb stumps of young, forelimb-amputated white rats. Additionally, in order to examine the possible role of mechanical effects of such device implantations, we have employed uncoupled devices delivering no current or potential difference. In the present experiments, in response to coupled device implantation, cartilage and bone were actively formed in the vicinity of the Pt electrode tip. These tissues contributed to the lengthwise extension of the limb and to the partial restoration of the distal humeral extremity. In limbs bearing the uncoupled electrical devices, qualitatively similar responses were noted, but osteogenesis was diminished in extent compared to that seen in limbs bearing the active or coupled devices. It is therefore necessary to consider the role of mechanical factors in the elicitation of the observed regenerative responses. Myogenesis was enhanced in electrically stimulated limbs, but not in those rats bearing uncoupled devices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051590309
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  • 162
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    Avian scale development. VI. Ultrastructure of the keratinizing cells of reticulate scales (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 111-121 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Reticulate scales develop as radial symmetrical anlagen, in contrast to scuttate scales which appear initially as “epidermal placodes.” Unlike scuttate scales whose outer and inner epidermal surfaces elaborate β-and α-type keratins, respectively, reticulate scales elaborate only one type of epidermal surface which has been reported to give an α-type, X-ray diffraction pattern. We find that, histologically and ultrastructurally, this surface differs from either epidermal surface of scuttate scales. The keratinizing cells become filled with long interweaving bundles of α-filaments which aggregate into rather homogeneous α-fibrils. Keratohyalin granules, which have been shown to be associated with other keratinizing regions in the bird, do not form during the keratinization of reticulate scale epidermis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051610107
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  • 163
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    Ultrastructure of the parathyroid gland of the japanese lizard in the spring and summer season (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 145-155 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of the parathyroid glands of adult Japanese lizards (Takydromus tachydromoides) in the spring and summer season was examined. The parenchyma of the gland consists of chief cells arranged in cords or solid masses. Many chief cells contain numerous free ribosomes and mitochondria, well-developed Golgi complexes, a few lysosome-like bodies, some multivesicular bodies and relatively numerous lipid droplets. The endoplasmic reticulum is mainly smooth-surfaced. Cisternae of the rough endoplasmic reticulum are distributed randomly in the cytoplasm. Small coated vesicles of 700-800 Å in diameter are found occasionally in the cytoplasm, especially in the Golgi region. The chief cells contain occasional secretory granules of 150-300 nm in diameter that are distributed randomly in the cytoplasm and lie close to the plasma membrane. Electron dense material similar to the contents of the secretory granules is observed in the enlarged intercellular space. These findings suggest that the secretory granules may be discharged into the intercellular space by an eruptocrine type of secretion. Coated vesicles (invaginations) connected to the plasma membrane and smooth vesicles arranged in a row near the plasma membrane are observed. It is suggested that such coated vesicles may take up extracellular proteins. The accumulation of microfilaments is sometimes recognized. Morphological evidence of synthetic and secretory activities in the chief cells suggests active parathyroid function in the Japanese lizard during the spring and summer season.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051610203
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  • 164
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    Intrinsic organization of snake dorsomedial cortex: An electron microscopic and golgi study (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 185-210 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cellular populations present in dorsomedial cortex in the snakes Constrictor constrictor, Natrix sipendon and Thamnophis sirtalis are described at the light microscopic level using Nissl and Golgi preparations as well as at the ultrastructural level. This area plays a central role in cortical organization in snakes by participating in major commissural and association projections.Systematic analyses of Golgi preparations indicate that five populations of neurons are present in dorsomedial area and have a preferential laminar distribution. Layer 1 stellate cells have somata positioned in the center of the outermost cortical layer, layer 1. Their dendrites are confined to this layer. Double pyramidal cells have their somata loosely packed in layer 2. Their dendrites bear a moderate population of spines, ascending through layer 1 to the pial surface and descending partially through layer 3. Some double pyramidal cells have somata displaced downwards into the upper third of layer 3. These neurons closely resemble the layer 2 double pryamidal cells. Layer 3 stellate cells have somata positioned in the middle third of layer 3. Their dendrites extend in all directions throughout layer 3 and through layer 2 into layer 1. Finally, horizontal cells have their somata positioned deep in layer 3, near the ventricle, and dendrites aligned concentric with the ventricle.Comparison of the organization of the known afferents to dorsomedial area with the distribution of the five cell types suggests that the laminations of both afferent fibers and dorsomedial neurons places specific neuronal populations in synaptic contact with specific sets of afferents.
    Additional Material: 21 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051610207
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  • 165
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    The extensor assembly in two species of opossum, Philander opossum and Didelphis marsupialis (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 337-345 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In considering primate and hominoid phylogeny, the fundamental position assigned to opossums is explained partially by the characteristic morphology of their hands and feet. One of the main functional features of the human hand is the ability to make a stabilized arch of the finger. Because the extensor assembly plays a key role in establishing an arched finger, the extensor systems of the digits of both the hands and feet were studied in two species of opossum, Philander opossum and Didelphis marsupialis.In the foot, two extensor tendons join in each toe to form one tendinous plate, which inserts onto the base of the second phalanx. Lumbricals join this plate along the tibial side, and interosseus insertions are found, although a true interosseus wing is lacking. At the proximal interphalangeal level, a terminal tendon takes its origin from this tendinous plate. This terminal tendon is oval in cross-section and contains elastic structures. Oblique bands arise from this terminal tendon and run proximally along the proximal interphalangeal joint inserting onto the base of the first phalanx. There are elastic structures in the flexor tendon on the dorsal side near its site of insertion.In the hand, the main extensor tendons are arranged differently and the interossei contribute substantially to the extensor assembly. Otherwise, the extensor assembly of the hands and feet are quite similar. The function of the so-called paratendinous intravaginal flexors is discussed as are evolutionary aspects of the extensor assembly.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051610307
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  • 166
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    Masthead (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051620201
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  • 167
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    Comprehensive schemata on the histology of the liver with consequences in terminology (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 211-219 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: New schemata of the liver are presented to discuss the combination of the three kinds of liver lobules known until today in a chalk-talk-manner. Terminology is also discussed. Further investigations are needed involving the construction and the vascular pattern of compound lobules of the three individial lobules of the liver in different species.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051620204
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  • 168
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    A comparative study of the differentiation and involution of the mullerian duct and wolffian duct in the male and female fetal mouse (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 175-209 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The present investigation has examined the ultrastructural differentiation of the genital ducts of both sexes of fetal mice. The emphasis of observations was placed on the phenomenon of morphogenetic cytolysis, particularly during the critical periods of Wolffian duct stabilization and Mullerian duct involution.Both developing and regressing genital ducts evidence extensive cytolysis. Autophagy appears to be the mechanism of morphogenetic change in the developing male Wolffian duct. Autophagy, heterophagy, and degeneration in situ are all prominent cytolytic activities in female Wolffian duct involution. The developing female Mullerian duct undergoes extensive morphogenetic remodeling by the mechanisms of autophagy, heterophagy, and degeneration in situ. In the male Mullerian duct, autophagy, heterophagy, and degeneration in situ are also prominent. In addition, whole degenerated epithelial cells are extruded from the duct early in regression which may be related to the transformation of periductal mesenchymal cells into an “epithelioid cell cuff” which does not form around the regressing Wolffian duct. The formation of this mesenchymal condensation surrounding the duct is also accompanied by the protrusion of Mullerian epithelial cell cytoplasm into the mesenchymal cells. These observations may evidence a complex epithelial-mesenchymal interaction occurring during male Mullerian duct involution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051620203
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  • 169
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    Editorial (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 311-311 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051620302
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  • 170
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    Structure and carbohydrate histochemistry of the intestine in ten teleostean species (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 343-359 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphology and carbohydrate histochemistry of ten teleostean intestines are compared. Although there is an absence of regional differentiation seen in higher vertebrates, specializations in some species occur in the form of intestinal swellings, pyloric ceca and recta, the latter separated by a valve. The intestinal lumen is lined by a simple columnar epithelium interspersed with goblet cells; multicellular intestinal glands are absent. Thick basement membranes seen in centrarchids and Perca flavescens closely resemble the stratum compactum found in the lamina propria of esocids. Granular cells, which vary in number from species to species, are often seen in the mucosa and submucosa but less frequently in the muscularis. In species with intestino-rectal valves, a rectum is easily defined by the abrupt appearance of lower mucosal folds, more goblet cells and a thicker muscularis. In the remaining species the above features appear gradually in the distal intestine. Goblet cells show species variations in localization of epithelial mucosubstances, which in broad terms are recognized as sulfomucins, sialomucins and neutral mucosubstances. In both proximal and distal intestines the majority of goblet cells contain sialomucin although small amounts of sulfomucin are also often present. In species without intestino-rectal valves, no changes in carbohydrates occur between proximal and distal intestines. The possible significance of the heterogeneous character of digestive tract mucosubstances is discussed.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/jmor.1051620305
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  • 171
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    The morphology of the sex pheromone gland in Drosophila grimshawi (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 177-183 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphology of a sex pheromone-producing gland found in the abdomen of Drosophila grimshawi males was studied by light and electron microscopy. This gland, consisting of two intra-anal lobes, contains cells that resemble those of other insect pheromone glands. However, in contrast to many other insect pheromone glands that release pheromone through the cuticle, cells of the intra-anal lobes secrete into a canaliculi-duct system that empties into the anal region. The liquid secretory product flows along the surface of the intra-anal lobes and is brushed onto the substrate by fingerlike projections on the lobes' surfaces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051610206
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  • 172
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    Ultrastructure of the sacculus and lagena in a moray eel (Gymnothorax sp.) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 241-256 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of the sacculus and lagena of a moray eel, Gymnothorax sp., was investigated using scanning and transmission electron microscopy. Particular emphasis was placed on the orientation of the sensory hair cells and on the ultrastructure of the sensory cells. The ciliary bundles on the sensory hair cells are of several types, each having a different size relationship between the kinocilium and stereocilia. The cell bodies of the sensory cells are similar to the mammalian type II sensory cell. There were no apparent differences in the cell bodies between sensory cells with different ciliary bundles.Hair cell orientation patterns on the saccular and lagenar maculae differ from patterns found in other fishes. The posterior side of the saccular macula in Gymnothorax has cells oriented dorsally and ventrally, as is typical in other non-ostariophysan species. The anterior end of the saccular macula has alternating groups of anteriorly and posteriorly oriented cells, a situation that differs from the more typical pattern in which anteriorly oriented cells are found on the ventral side of the macula while posteriorly oriented cells cover the dorsal side of the macula. The orientation of cells on the lagena includes ventral cells that are located above a group of dorsally oriented cells. In many other non-ostariophysans, ventrally oriented cells are generally posterior to the dorsally oriented cells.
    Additional Material: 16 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051610302
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  • 173
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    Masthead (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051620101
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  • 174
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    The blood supply of muscle spindles in some mammals and the pigeon (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 323-335 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The blood supply of muscle spindles was studied in serial cross sections in macaque, cat, rabbit, guinea pig, mouse and pigeon muscles which had been incubated in a medium containing 3,3′ diaminobenzidine. Lumina of blood vessels were recognized by the reaction product that was localized within erythrocytes. The outer capsule was well vascularized, but few or no capillaries were seen in the periaxial space. The inner spindle capsule, which closely invests the axial bundle, was rarely contacted by periaxial capillaries at the equator and juxtequator. Capillaries occurred more frequently adjacent to intrafusal fibers at the polar region and beyond the end of the outer capsule. Shorter diffusion distances and, usually, higher capillary densities were found at the polar region than at the spindle midsection. This suggests that transcapillary exchange at the polar segment is nearer to conditions prevalent in extrafusal muscle than elsewhere in the spindle, provided the inner and outer capsules are not less permeable at the poles than at the midsection. Differences in blood supply among mammalian species appear to be related to receptor size.
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  • 175
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    Origin and fate of germ cells in male and female embryos of Haplothrips verbasci (Osborn) (Insecta, Thysanoptera, Phlaeothripidae) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 323-343 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Comparison of germ cells in male and female embryos of the arrhenotokous thrips, Haplothrips verbasci, yields the following observations: A mean of 11 cleavage energids enter the posterior pole plasm of the egg after the sixth cleavage division and apparently become pole cells when they take up polar granules in their cytoplasm. The cells proliferate asynchronously prior to and during anatrepsis to yield a mean of 36 germ cells in male embryos and 31 in females. Visible sexual differentiation of germ cells begins during germ band elongation and is completed shortly after the appearance of appendages. Female germ cells are larger than those of the males and may contain two nucleoli. The germ cells separate into two groups just before katatrepsis and mesodermal cells collect about these to form the primary epithelial sheaths of the gonads and the primordia of the gonoducts shortly after revolution is completed. Each gonad contains a mean of 13 germ cells in male embryos and 7 in females - a number that persists until mitosis resumes after hatching. During ketatrepsis, a mean of 11 germ cells in male embryos and 2.6 in females fail to be enclosed within the gonads, become dispersed in the yolk and perhaps transform into vitellophages.Germ cell development in H. verbasci embryos resembles similar events taking place in psocid embryos, providing additional evidence for a close phylogenetic relationship between Thysanoptera and Psocoptera.
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    Presence and development of a sensory formation in the eyestalk of the crayfish, Astacus leptodactylus (Nordmann, 1842), during its embryonic, larval and adult lifeThis study was partially sponsored by C.N.R.S. (France) under grànt A.T.P. International 1976-2602. (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 39-51 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A sensory papilla is described in the eyestalk of the crayfish Astacus leptodactylus during the last embryonic stages and during larval stages by light microscopy. This region was also investigated with the scanning electron microscopy, which showed sensory hairs in the postmolt adult; they disappear during intermolt and premolt. Simultaneous cyclic changes in hair papillae are observed in the hypodermis. The possibility of a chemoreceptive function is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051610104
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  • 177
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    Membrane production and yolk degradation in the early fly embryo (Calliphora erythrocephala meig.): An ultrastructural analysis (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 53-77 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Formation of nuclear envelopes during the last cleavage mitosis and the formation of the cell membranes during the cellularization of the blastoderm have been studied ultrastructurally in the blowfly egg. Dense bodies arising from yolk granules by budding could contain membrane material destined to be incorporated into the new membranes of the blastoderm. The presence of transitional structures indicates that these bodies can be converted into dark multivesicular bodies. Large amounts of endoplasmic reticulum are found around the mitotic nuclei. Clusters or branched chains of vesicles associated with this are interpreted as evidence for the formation of endoplasmic reticulum by the breakdown of dark multivesicular bodies. Nuclear envelopes of mitotic daughter nuclei probably originate from endoplasmic reticulum. The egg contains both intranuclear and extranuclear annulate lamellae.The main events of cytokinesis are furrow initiation and cell membrane growth during the slow first phase, but probably only cytokinetic movement during the rapid second phase. On the assumption that cell membrane growth occurs by incorporation of complete membrane pieces, the addition of coated vesicles and/or light multivesicular bodies is definitely most probable. Some intermediate profiles indicate that light and dark multivesicular bodies are related. The membrane needed for second phase cytokinesis could well be provided by the unfolding of surface microvilli and protuberances of the furrow canal.
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    URL: http://dx.doi.org/10.1002/jmor.1051610105
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  • 178
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    Countercurrent blood vessel arrangement in beaver (Castor canadensis) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 169-175 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The vascular anatomy of five beavers (Castor canadensis) was studied by dissection and injection of arteries and veins with vinyl acetate. There is extensive countercurrent arrangement of arteries and veins distal to and including the common iliac artery and veins. Two types of countercurrent vessels occur (1) a venae comitantes type in which two or three veins surround a central artery, and (2) a modified rete type. The retia are located proximal to the large flat tail and the webbed hind feet. Two bypass veins are described for the feet and tail and the significance of these structures in temperature regulation is stressed.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051610205
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    Masthead (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051610301
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  • 180
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    Ultrastructure of the type “B” cells in the rectal pad epithelium of Locusta migratoria (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 221-232 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The electron microscopical structure of the type “B” cells in the rectal pad epithelium of Locusta is described. The type “B” cells occur singly in the distal region of the rectal pad epithelium. They are characteristically goblet shaped and join with contiguous type “A” or rectal pad cells, near the apical surface by means of a restricted region of septate desmosomes. Type “B” cells possess a microvillate apical membrane, with the villi arranged as a rosette overlying the apical inaginations of adjacent type “A” cells.Large numbers of microtubules and vacuoles of various sizes containing an assortment of inclusions are present in the apical region of the type “B” cells. Many of the microtubules insert distally on hemidesmosomes located in the apical plasma membrane. Rough endoplasmic reticulum and mitochondria are also present but neither are abundant. The possible significance of these findings is discussed.
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    URL: http://dx.doi.org/10.1002/jmor.1051590205
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  • 181
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    The development of amphids and amphidial glands in adult Syngamus trachea (Nematoda: Syngamidae) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 299-321 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Nematode amphids are a pair of lateral cephalic sense organs, each comprising a group of sensory endings terminating in a cuticle-lined pit. In Syngamus trachea, a parasite of birds, each amphid is surrounded by two non-nervous supporting elements, a large gland cell basally and a smaller supporting cell anteriorly. The amphidial glands display high levels of secretory activity from five to six days postinfection. Secretory material is discharged through the lumen of the sense organ onto host tissue. The ultrastructure of amphids and amphidial glands has been investigated in newly moulted, immature and mature adults to trace the development of glandular activity and its effect on amphid-amphidial gland relationships. In newly moulted adults, the glands have very low levels of secretory activity and appear to act only as supporting cells to the amphids. As secretory activity increases, the gland cell membrane surrounding the sensory endings is elaborated into a reticulum which probably forms the secretory surface. In mature adults the amphid pit is swollen and filled with secretion; the sensory endings are relegated to the periphery of the lumen. It is suggested that amphidial glands develop from typical supporting cells, but acquire a new role possibly associated with parasite attachment.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051600304
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  • 182
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    Histochemical and ultrastructural features of the aorta of the slug (Limax maximus) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 1-21 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: As a part of a continuing study of unusual molluscan tissues, the “chondroid” tissue (Hyman, '67) associated with the anterior and posterior aortae of the slug (Limax maximus) was examined by light and electron microscopy. Unlike the odontophoral tissue of this species (Curtis and Cowden, '77), the “chondroid” tissue comprising the adventitial layer of the aorta consists of large, glycogen-filled cells with characteristic arrays of pores in their plasma membranes resembling those of the “globular” cells (Rogers, '69; Fernandez, '71); “fibrocytes” (Nicaise et al., '66; Baleydier et al., '69; Nicaise, '73); “Blasenzellen” or “Leydig” cells (Wondrak, '69; Stang-Voss, '70; Buchholz et al., '71; Stang-Voss and Staubesand, '71; Wolburg-Buchholz, '72); or “pore” cells (Sminia, '72; Beltz, '77) of other mollusks. The anterior and posterior aortae are very similar in organization, except that the anterior aorta is larger in diameter; its wall is thinner; and it lacks calcification. Both the anterior and posterior aortae possess a loosely organized (incomplete) endothelial layer surrounded by two layers of innervated smooth muscle. The smooth muscle cells possess fibrous surface specializations resembling hemidesmosomes as well as large numbers of tubular or rounded vesicles in association with their plasma membranes. Blood cells (amoebocytes) containing large glycogen deposits and distinctive membrane-enclosed cytoplasmic inclusions can be found occasionally in the walls of the vessels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051610102
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  • 183
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    The hind limb musculature of the brown kiwi, Apteryx australis mantelli (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 33-73 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The most complete account of the hind leg muscles of the kiwi was published a century ago by Sir Richard Owen, in his seventy-fifth year. This extensively-cited work has several omissions and errors, and while certain of these were corrected by subsequent authors, sufficient uncertainty remains to warrant a reinvestigation. In the present study a detailed description of the hind leg musculature is given, based upon dissections of two frozen specimens. An indication of the possible function of each muscle is given by assessing its size, action, and fiber-arrangement, together with tentative data on the relative abundance of twitch and tonus fibers.The correlation between surface features of bones and muscle attachments is investigated with a view to interpreting palaeontological material. Although the limb and pelvic bones are marked by numerous features which suggest muscle attachments, relatively few can be positively identified with specific muscles. Only 23% of the muscle origins and insertions can be identified, and, with three possible exceptions, no indication of relative size is given by the scars. The possibility of being able to reconstruct the musculature of the kiwi from its skeletal anatomy, much less that of its extinct relatives, is remote.
    Additional Material: 26 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051600105
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  • 184
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    A model to explain the posterior limit of the bite point in reptiles (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 165-168 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A biomechanical model of the jaw mechanism in some reptiles is presented. Symmetrical muscle activity that produces equal forces on both sides of the head is assumed. The model predicts the position of the most posterior bite point and offers a functional explanation for this prediction. Turtles are used to illustrate the idea.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051600204
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  • 185
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    Masthead (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051600201
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  • 186
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    Organization of nucleus rotundus, a tectofugal thalamic nucleus in turtles. I. Nissl and Golgi analyses (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 121-141 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study consists of a detailed cytoarchitectonic and Golgi analysis of a major tectofugal thalamic nucleus in the red-eared turtle, Pseudemys scripta elegans. Neurons in nucleus rotundus have a unimodal soma size distribution and a common dendritic branching pattern. They have long dendrites which undergo sparse, dichotomous branchings and contribute to dendritic fields that cover a third to half the dimensions of the nucleus. Spicules, 1-2 μ long, and complex appendages, 5-20 μ long, are found with low density on many dendrites in Golgi-Kopsch material. A few cells have beaded dendritic processes. Three cytoarchitectural regions can be differentiated in nucleus rotundus: a shell, a cell-poor region and a core. The shell is a monolayer of somata forming the peripheral boundary of most of the nucleus. The cell-poor region forms a thin zone concentric with and internal to the shell. Shell cells send some of their dendrites concentrically within this zone and others radially into the core region. Core neurons are dispersed within the neuropil of the nucleus and usually have spherical dendritic fields. However, peripheral core neurons have asymmetrical fields, so their dendrites do not extend beyond the shell. Caudomedial and central subregions of the core can be defined on the basis of neuronal density and cytology. Somata in the caudomedial area of the core are densely packed and have slightly darker staining cytoplasm than those in the central subregion. However, their dendrites are similar to those of the central core neurons. There is extensive dendritic overlap between the two subregions.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051600202
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  • 187
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    Masthead (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051610101
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  • 188
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    Glycogen metabolism in the prelaid chick embryo (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 23-38 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Glycogen metabolism has been studied during the development of the early chick embryo, at the cytochemical and ultrastructural levels. Two waves of glycogen synthesis and breakdown have been found. In the first, free clusters of glycogen particles are synthesized at late oogenesis. These clusters are found later in invaginations of the membrane of vesicles containing a floc-cular material (FLOV). The glycogen clusters are degraded there during ovulation and the first hours in the oviduct. The second wave of glycogen synthesis begins before cleavage, reaching a maximum at mid-uterine age. This second wave occurs in another type of vesicle (GLYV), which eventually disintegrates releasing free clusters of glycogen granules. This glycogen is degraded in membranous structures containing a floccular material, as in the first wave of degradation. The degradation ends at the late uterine stages, and at the same time numerous ribosomes are formed. This period corresponds to area pellucida formation, which probably depends on the energy liberated during the second wave of glycogen degradation.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051610103
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  • 189
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    Studies on the tardigrades. IV. Fine structure of the hindgut of Milnesium tardigradum doyère (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 79-109 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The hindgut of the semi-terrestrial tardigrade, Milnesium tardigradum was examined with light and electron microscopy. The hindgut consists of a cloaca and an anterior hindgut. It is delineated anteriorly by the pylorus into which four Malpighian tubules empty and posteriorly, by a broad cloacal slit. A single oviduct enters the hindgut at the junction between the cloaca and the anterior hindgut. Two pairs of muscles insert on the cloaca and anterior hindgut respectively. Electron microscopic observations demonstrate that the anterior hindgut is a specialized transporting epithelium. The luminal surface is covered by a thin layer of cuticle which penetrates into channel-like invaginations. Numerous mitochondria are concentrated apically. The basal and lateral surfaces are also folded. The cells are joined apically by deep tight junctions and a simple basal lamina lines the entire hindgut. The cloaca which receives the contents of the gut and Malpighian tubules as well as gametes of the reproductive tract is a transitional organ that exhibits several characteristics of the hypodermis and anterior hindgut. The cuticle of the cloaca changes sequentially from the complex structure of the integument to a simple layer of the anterior hindgut. The function of the hindgut is discussed with emphasis on the possible response of the anterior hindgut to a hypoosmotic habitat, evaporative water loss during the induction of anhydrobiosis and low oxygen tension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051610106
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  • 190
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    The fine structure of blood follicles in the earthworm genera Amynthas and Lumbricus (Annelida: Oligochaeta) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 123-143 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Blood follicles of the earthworm Amynthas are hemoglobin-containing, sac-like dilatations of blood vessels which connect to the general circulation. Grape-like clusters of follicles are found posterior to the pharynx, among tufts of micronephridia, and single follicles are located among cells of the pharyngeal gland. In Lumbricus, follicles take the form of simple swellings and irregular-shaped diverticula of nephridial capillaries.The fundamental structure of the wall of follicles and of vessels in both genera is the same and consists of two layers: an extracellular vascular lamina and an outer (coelomic) covering of smooth muscle-like myoperithelial cells. Hemocytes may be free and circulating or they may facultatively attach to the vascular lamina as littoral cells, constituting an incomplete endothelium-like surface. Hemocytes that appear to be in the process of attaching or detaching are rounded, while adherent cells are flattened and elongate. Free and littoral hemocytes actively endocytose packets of circulating extracellular hemoglobin.Hemocytes within follicles possess radiating cell processes which also endocytose hemoglobin. Although these cells were presumed to secrete hemoglobin, staining with 3,3′-diaminobenzidine confirms the presence of hemoglobin only within pinosomes and not within protein-synthesizing or packaging organelles. The presence of hemosiderin-like bodies suggests that follicular hemocytes catabolize hemoglobin.Blood follicles apparently provide a means of significantly increasing cell-surface area for hemoglobin processing, without substantially increasing the volume and pumping load of the circulatory system.
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    URL: http://dx.doi.org/10.1002/jmor.1051610202
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  • 191
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    Masthead (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051610201
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  • 192
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    The mouthparts of female Corethrella brakeleyi and C. wirthi (Diptera: Chaoboridae) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 157-167 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mouthparts of female Corethrella brakeleyi and C. wirthi were studied using light and electron microscopy. Mandibles, hypopharynx and labium are highly sclerotized and are modified for obtaining blood meals. All structures were larger in C. brakeleyi than in C. wirthi except mandibular and hypopharyngeal teeth; these were smaller and more numerous in C. brakeleyi. The labium of both species terminates in peg-like structures which are similar to those reported from several genera of mosquitoes. Sensillae on the second segment of the maxillary palps appear to be identical to those described in both biting and nonbiting male and female blackflies.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/jmor.1051610204
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  • 193
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    The structure of the canary's incubation patch (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 425-451 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The gross morphology, histology and ultrastructure of the canary's incubation patch and the ventral apterium from which it arises are described. The apterium is vascularized by pectoral, external mammary, incubation, and prepubic arteries. It is innervated by cutaneous branches of spinal nerves. It has a surface area of 6 cm2.Its epidermis is a stratified squamous epithelium with basal, intermediate, transitional and cornified layers. Cells in the stratum germinativum contain a normal array of organelles, but are characterized by tonofilaments, desmosomes and interdigitating surfaces. Cellular organelles disappear in the stratum transitivum and are replaced by large vacuoles and keratohyalin bands. Nonmyelinated nerve fibers are abundant in the stratum germinativum.The dermis consists of (1) an avascular layer of dense collagen subjacent to the epidermis and containing many nonmyelinated nerves, and (2) an underlying layer of areolar connective tissue containing blood vessels, lamellar corpuscles and nerves. A layer of coarse elastic fibers, reinforced by collagen and smooth muscle, separates the dermis from subcutaneous tissue.In contrast to the ventral apterium, the incubation patch is featherless and visibly hypervascular and edematous. Its epidermis is both hypertrophic and hyperplastic. Large spaces separate cells in the stratum germinativum. The visible hypervascularity is due to hyperemia and increased number and size of blood vessels in the dermis. Visible edema is due to the accumulation of fluid interstitially. Although no histological differences exist among various regions of the ventral apterium, such differences are present in the incubation patch.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051620309
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  • 194
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    Cell death and optic fiber penetration in the optic stalk of the chick (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 67-75 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The role of dying cells in the optic stalk in relation to retinal fiber migration was investigated in the chick embryo. Cell death was analysed at various stages of development by counting pycnotic nuclei and also by the Gomori acid phosphatase reaction, while nerve fibers were visualised by the Bodian method. A wave of cell death, beginning in the neural retina at stage 18 and advancing with time through the stalk towards the diencephalon, occurred simultaneously or slightly prior to differentiation and migration of ganglion cell axons. Cell death stopped and gliogenesis occurred in the stalk after penetration by retinal fibers. Cell death occurred in the stalk even when fiber penetration was prevented by optic cup ablation. In this case, necrosis ensued until almost complete degeneration of the stalk, usually within three days after the operation, and gliogenesis did not occur. As the stalk degenerated, its cells became heavily pigmented. These observations suggest that the onset of cell death in the optic stalk is determined prior to and independently of retinal fiber penetration. On the other hand, cessation of cell death and subsequent gliogenesis occur only in the presence of ingrowing optic fibers.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051620105
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  • 195
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    Ultrastructure of an exocrine dermal gland in the gills of the grass shrimp, Palaemonetes pugio: Occurrence of transitory ciliary axonemes associated with the sloughing and reformation of the ductule (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 281-307 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Exocrine dermal glands, comparable to the class 3 glandular units of insects, are found in the gills of the grass shrimp, Palaemonetes pugio. The dermal glands are composed of three cells: secretory cell, hillock cell and canal cell. Originating as a complex invagination of the apical cytoplasm of the granular secretory cell, a duct ascends through the hillock and canal cells to the cuticular surface. The duct is divisible into four regions: the secretory apparatus in the granular secretory cell, the locular complex, the hillock region within the hillock cell and the canal within the canal cell. A tubular ductule is contained within the latter two regions. As the ductule ascends to the cuticular surface, its constitution gradually changes from one of a fibrous material to one which possesses layers of epicuticle. During the proecdysial period, the ductule is extruded into the ecdysial space and this is followed by the secretion of a new ductule. Temporary ciliary structures, located near the secretory apparatus of the secretory cell, are associated with the extrusion and reformation of the ductule. Characterized only by a basal body and rootlets throughout most of the intermolt cycle, the ciliary organelles give rise to temporary axonemic processes which ascend through the ductule toward the ecdysial space at the onset of proecdysis. Subsequently, the old ductule is sloughed off and a new ductule is reformed around the ciliary axonemes. Following this reformation, the ciliary axonemes degenerate. The function of cytoplasmic processes, derived from the apical cytoplasm of the secretory cell, is also discussed.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051610304
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  • 196
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    Ordered membrane particles in rhabdomeric microvilli of the housefly (Musca domestica L.) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 161 (1979), S. 309-321 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Rhabdomeric microvilli of the housefly were freeze-fractured (FF) and thin sectioned (TS) for ultrastructural examination. Ordered files of closely packed membrane particles (82 Å wide, 250 Å long) were seen (FF) on the microvillar membrane (usually E face). The long axis of each particle was canted about 45° to that of the microvillus. Occasionally particles in this array appeared on the P face. It is hypothesized that ordered particles may represent either a photopigment precursor stock, a second photolabile pigment, or the newly discovered sensitizing, UV-absorbing, photostable visual pigment. In the underlying membrane leaflet (P face) were found spherical (85 Å diameter) unoriented particles in a concentration of about 6,000/μm2. The size, shape and density of these structures are compatible with those of rhodopsin particles. These particles also covered the basal area of each microvillus. The findings from TS material were difficult to correlate with those from FF replicas. At high magnification the former showed that the plasma membrane of the transected microvillus is composed of spherical, hollow subunits (averaging 43 Å diameter), sometimes fused to form double, 86 Å units. These substructures were closely packed and continuous around the microvillus. This beaded plasma membrane, in rare cases, was doubled around the microvillus. In other instances the plasma membranes were continuous between neighboring microvilli. The physiological implications of these ultrastructural features are discussed.
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    URL: http://dx.doi.org/10.1002/jmor.1051610305
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  • 197
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    Interactions between Tectal Radial Cells in the Red-Eared Turtle, Pseudemys scripta elegans: An Analysis of Tectal Modules (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 17-36 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The optic tectum is a major subdivision of the visual system in reptiles. Previous studies have characterized the laminar pattern, the neuronal populations, and the afferent and efferent connections of the optic tectum in a variety of reptiles. However, little is known about the interactions that occur between neurons within the tectum. This study describes two kinds of interactions that occur between one major class of neurons, the radial cells, in the optic tectum of Pseudemys using Nissl, Golgi and electron microscopic preparations.Radial cells have somata which bear long, radially oriented apical dendrites from their upper poles and short, basal dendrites from their lower poles. They are divided into two populations on the basis of the distribution of their somata in the tectum. Deep radial cells have somata densely packed in the stratum griseum periventriculare. Their plasma membranes form casual appositions. Middle radial cells have somata scattered throughout the stratum griseum centrale and stratum fibrosum et griseum superficiale and do not contact each other. The apical dendrites of both populations of radial cells participate in vertically oriented, dendritic bundles. The plasma membranes of the dendrites in these bundles form casual appositions in the deeper tectal layers and chemical, dendrodenritic synapses within the stratum fibrosum et griseum superficiale. The synapses have clear, round synaptic vesicles and slightly asymmetric membrane densities. Thus, radial cells interact via both casual appositions and chemical synapses.These interactions suggest that radial cells may form a basic framework in the tectum. Because both populations of radial cells extend into the stratum fibrosum et griseum superficiale and stratum opticum, they may receive input from some of the same tectal afferent systems. Because the deep radial cells alone have somata and dendrites in the deep tectal layers, they may receive additional inputs that the middle radial cells do not. Neurons in the two populations interact via chemical dendrodendritic synapses, thereby forming vertically oriented modules in the tectum.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051620103
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    The telotrophic-meroistic ovary of megaloptera. I. The ontogenetic development (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 37-65 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Sialis flavilatera L. (Sialidae, Megaloptera) has telotrophic-meroistic ovarioles. The germ cells of the tropharium are organized into two distinct tissues, the central syncytium and the germ cell tapetum. The central syncytium consists of nurse cell nuclei embedded in a common cytoplasm which is rich in ribosomes and mitochondria. Cell membranes are totally absent. The germ cell tapetum surrounds the syncytium and consists of a monolayer of cells, each of which is connected with the central syncytium by an intercellular bridge. The oocytes differentiate from basal tapetum cells by previtellogenic growth. Their nutritive cords remain connected to the central syncytium by the intercellular bridge.Ovariole development starts soon after hatching with the immigration of germ cells into the ovariole-anlagen and is finished during pupal stages 23 months later. In apical regions of each tropharium, mitoses occur throughout larval life. The descendants enter the prophase of meiosis which lasts until pre-vitellogenesis; thus, a differential gradient of position and time is established. About 12 months after hatching, the central syncytium arises at the base of the tropharium from a membrane labyrinth in which intercellular bridges are entangled. Evidence is presented that endopolyploidization does not occur during germ cell differentiation.Finally, the results are compared with those found in Hemiptera and polyphage Coleoptera. The great diversities are interpreted as an indication for a polyphyletic origin of the telotrophic ovary.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051620104
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    Sense organs on the antennal flagellum of the mimosa webworm, Homadaula anisocentra (Lepidoptera, Glyphipterygidae) (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 163-173 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Five different types of sense organs were found on the antennal flagellum of Homadaula anisocentra. These were (1) tactile hairs; (2) thick-walled chemoreceptors; (3) thin-walled chemoreceptors of several kinds; (4) styloconic chemoreceptors and (5) small chemoreceptor pegs in shallow depressions. No coeloconic sense organs were seen.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051620202
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  • 200
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    Growth and differentiation of secondary malpighian tubules in the cockroach, Periplaneta americanaThis work was submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biology at Northwestern University and was supported in part by the National Institutes of Health under Research Grants AM 14993, AM 14993, AM 19189, and FR 7028 to James L. Oschman and Betty J. Wall.An abstract of this work was published in J. Cell. Biol., 75: 32a, 1977. (1979)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 162 (1979), S. 389-411 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Four differentiated Malpighian tubules (primary tubules) extend from the junction of the midgut and hindgut in newly hatched Periplaneta americana. Secondary tubules begin to develop near the base of the primary tubules before hatching and successive nymphal molts. The newly initiated tubules undergo cell division and extensive elongation through the middle of the following intermolt period. During this time, the cells of the distal, middle, and lower middle tubule regions are surrounded by a cellular sheath, have few cytoplasmic processes extending along their basal surfaces, have a small or nonexistent lumen, and contain extremely dilated cisternae of endoplasmic reticulum. The cellular sheath differentiates into the muscle which coils around the mature tubule. Tubules which begin development toward the end of one intermolt period begin to undergo cytodifferentiation toward the end of the next intermolt period. By the middle of an additional intermolt period, the basal infoldings and microvilli of cells in the distal, middle, and lower middle regions have the conformations typical for those regions in differentiated tubules; granular concretions and stellate cells are present within the middle region of the tubule.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051620307
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