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  • Ultrastructure  (354)
  • Immunocytochemistry  (151)
  • Angiosperms  (135)
  • Seismology
  • Springer  (654)
  • Division of Earthsciences, Seismological Laboratory, California Institute of Technology
  • Dover Publ.
  • 2010-2014  (1)
  • 2000-2004  (25)
  • 1980-1984  (628)
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  • 1
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    Springer
    Publication Date: 2017-04-04
    Description: n/a
    Description: Published
    Description: 125-127
    Description: 3.3. Geodinamica e struttura dell'interno della Terra
    Description: restricted
    Keywords: Core-mantle boundary topography ; Seismology ; 04. Solid Earth::04.01. Earth Interior::04.01.03. Mantle and Core dynamics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 2
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    In:  Professional Paper, Early Warning Systems for Natural Disaster Reduction, Berlin, Springer, vol. 1, no. 16, pp. 479-480, (ISBN 1-86239-165-3, vi + 330 pp.)
    Publication Date: 2003
    Keywords: Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Earthquake ; China ; Project report/description ; Seismology ; Kueppers ; Kuppers
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  • 3
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    In:  Early Warning Systems for Natural Disaster Reduction, Berlin, Springer, vol. 37, no. 16, pp. 487-494, (ISBN 0080419208)
    Publication Date: 2003
    Keywords: Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Project report/description ; Seismology ; Seismicity ; Kueppers ; Kuppers
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  • 4
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    In:  Bull., Open-File Rept., Early Warning Systems for Natural Disaster Reduction, Berlin, Springer, vol. 22, no. 16, pp. 453-460, (ISBN 0080419208)
    Publication Date: 2003
    Keywords: Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Japan ; Seismology ; Seismicity ; Tsunami(s) ; Kueppers ; Kuppers
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  • 5
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    In:  Berlin Heidelberg, Springer, vol. 98, no. ALEX(01)-FR-77-01, AFTAC Contract F08606-76-C-0025, pp. 95-104, (ISBN: 1-4020-1592-5)
    Publication Date: 2003
    Keywords: digital signal analysis (also DSP) ; DSP ; Seismology ; Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; earthquake ; warning ; Seismic networks ; Data analysis / ~ processing ; Location ; Detectors ; Time series analysis ; Seismology
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  • 6
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    In:  Professional Paper, Methods and Applications of Signal Processing in Seismic Network Operations, Berlin Heidelberg, Springer, vol. 98, no. 16, pp. 131-148, (ISBN 0080419208)
    Publication Date: 2003
    Keywords: digital signal analysis (also DSP) ; DSP ; Seismology ; Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; earthquake ; warning ; Seismic networks ; Data analysis / ~ processing ; Location ; Detectors ; Time series analysis ; Seismology ; Boedvarsson ; Bodvarsson
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  • 7
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    In:  Professional Paper, Early Warning Systems for Natural Disaster Reduction, Berlin, Springer, vol. 1002, no. 231, pp. 441-446, (ISBN 1-4020-1729-4)
    Publication Date: 2003
    Keywords: Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Seismology ; Seismic networks ; Real time earthquake monitoring ; Kueppers ; Kuppers
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  • 8
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    In:  Bull., Polar Proj. OP-O3A4, Early Warning Systems for Natural Disaster Reduction, Berlin, Springer, vol. 24, no. 4, pp. 425-431, (ISBN 0080419208)
    Publication Date: 2003
    Keywords: Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Earthquake precursor: prediction research ; Seismology ; Mexico ; Kueppers ; Kuppers
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  • 9
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    In:  Bull., Open-File Rept., Methods and Applications of Signal Processing in Seismic Network Operations, Berlin Heidelberg, Springer, vol. 98, no. 16, pp. 149-172, (ISBN 1-86239-165-3, vi + 330 pp.)
    Publication Date: 2003
    Keywords: digital signal analysis (also DSP) ; DSP ; Seismology ; Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Seismic networks ; Data analysis / ~ processing ; Location ; Detectors ; Time series analysis ; Seismology
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  • 10
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    In:  Bull., Open-File Rept., Early Warning Systems for Natural Disaster Reduction, Berlin, Springer, vol. 9, no. 16, pp. 228, (ISBN 1-86239-165-3, vi + 330 pp.)
    Publication Date: 2003
    Keywords: Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Earthquake precursor: prediction research ; Seismicity ; warning ; time ; Seismology ; micro-zonation ; Seismic networks ; Project report/description ; Rapid damage assessment ; Earthquake hazard ; Earthquake risk ; monitoring ; Kueppers ; Kuppers ; Stefansson ; SIL
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  • 11
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    In:  Professional Paper, Open-File Rept., Early Warning Systems for Natural Disaster Reduction, Berlin, Springer, vol. 14B, no. 16, pp. 465-469, (ISBN 1-86239-165-3, vi + 330 pp.)
    Publication Date: 2003
    Keywords: Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Seismology ; Seismicity ; Kueppers ; Kuppers
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  • 12
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    In:  Professional Paper, Open-File Rept., Early Warning Systems for Natural Disaster Reduction, Berlin, Springer, vol. 1, no. 16, pp. 471-477, (ISBN 0080419208)
    Publication Date: 2003
    Keywords: Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Romania ; Seismology ; Seismicity ; Earthquake engineering, engineering seismology ; Karlsruhe ; Kueppers ; Kuppers ; SFB ; 461
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  • 13
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    In:  Professional Paper, Open-File Rept., Early Warning Systems for Natural Disaster Reduction, Berlin, Springer, vol. 1, no. 2, pp. 462-464, (ISBN 0080419208)
    Publication Date: 2003
    Keywords: Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Real time earthquake monitoring ; Seismicity ; Seismology ; China ; Kueppers ; Kuppers
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  • 14
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    In:  Professional Paper, Open-File Rept., Early Warning Systems for Natural Disaster Reduction, Berlin, Springer, vol. Memoir 157, no. 1, pp. 433-440, (ISBN 0080419208)
    Publication Date: 2003
    Keywords: Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Earthquake precursor: prediction research ; Turkey ; Seismicity ; warning ; time ; Seismology ; micro-zonation ; Seismic networks ; Project report/description ; Rapid damage assessment ; Earthquake hazard ; Earthquake risk ; monitoring ; Isikara ; Yalcin ; Kueppers ; Kuppers ; Erguenay ; Ergunay
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  • 15
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    In:  Professional Paper, Open-File Rept., Early Warning Systems for Natural Disaster Reduction, Berlin, Springer, vol. Memoir 157, no. 1, pp. 527-532, (ISBN 0080419208)
    Publication Date: 2003
    Keywords: Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Earthquake precursor: prediction research ; Indonesia ; Java ; Seismicity ; warning ; time ; Seismology ; Seismic networks ; Project report/description ; Earthquake hazard ; Earthquake risk ; monitoring ; Kueppers ; Kuppers ; Luehr ; Luhr
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  • 16
    Electronic Resource
    Electronic Resource
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    Journal of comparative physiology 186 (2000), S. 347-357 
    ISSN: 1432-1351
    Keywords: Key words Crustacean ; Sensorimotor ; Ultrastructure ; Multilamellar sheath ; Myelinated axons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Speed of nerve impulse conduction is greatly increased by myelin, a multi-layered membranous sheath surrounding axons. Myelinated axons are ubiquitous among the vertebrates, but relatively rare among invertebrates. Electron microscopy of calanoid copepods using rapid cryofixation techniques revealed the widespread presence of myelinated axons. Myelin sheaths of up to 60 layers were found around both sensory and motor axons of the first antenna and interneurons of the ventral nerve cord. Except at nodes, individual lamellae appeared to be continuous and circular, without seams, as opposed to the spiral structure of vertebrate and annelid myelin. The highly organized myelin was characterized by the complete exclusion of cytoplasm from the intracellular spaces of the cell generating it. In regions of compaction, extracytoplasmic space was also eliminated. Focal or fenestration nodes, rather than circumferential ones, were locally common. Myelin lamellae terminated in stepwise fashion at these nodes, appearing to fuse with the axolemma or adjacent myelin lamellae. As with vertebrate myelin, copepod sheaths are designed to minimize both resistive and capacitive current flow through the internodal membrane, greatly speeding nerve impulse conduction. Copepod myelin differs from that of any other group described, while sharing features of every group.
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  • 17
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    Mycorrhiza 10 (2000), S. 15-21 
    ISSN: 1432-1890
    Keywords: Anthoceros punctatus ; Arbuscular mycorrhiza ; Bryophytes ; Glomus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Glomus claroideum (Schenck & Smith emend. Walker & Vestberg) were investigated for ability to form arbuscular mycorrhiza-like symbioses with the hornwort Anthoceros punctatus (L.). Spores were transferred to a cellulose acetate filter on water agar and a small portion of an Anthoceros thallus was placed directly upon the spores. Light-microscope observations 20 days after inoculation revealed branched hyphae growing within the thallus. After 45 days, arbuscules and vesicles were studied by light- and electron-microscopy. After 60 days in water agar culture, the colonised Anthoceros thalli were transferred to a low-nutrient medium agar. Hyphae spread in the agar and newly formed spores were observed 5 weeks after the transfer. After 4 months, about 1000 spores were formed in each Petri dish. This is the first report of an experimentally established arbuscular mycorrhiza-like symbiosis between an identified fungus belonging to the Glomales and a bryophyte.
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  • 18
    ISSN: 1615-6102
    Keywords: Arabinogalactan proteins ; Fiber ; Linum usitatissimum ; Immunocytochemistry ; Polysaccharide ; Secondary wall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The deposition and formation of a thick secondary wall is a major event in the differentiation of flax (Linum usitatissimum) fibers. This wall is cellulose-rich; but it also contains significant amounts of other matrix polymers which are noncellulosic such as pectins. We have used immunocytochemical techniques with antibodies specific for various epitopes associated with either pectins or arabinogalactan proteins (AGPs) to investigate the distribution of these polymers within the walls of differentiating young fibers of 1- and 2-week-old plants. Our results show that different epitopes exhibit distinct distribution patterns within fiber walls. Unesterified pectins recognized by polygalacturonic acid-rhamnogalacturonan I (PGA/RG-I) antibodies and rhamnogalacturonan II recognized by anti-RG-II-borate complex antibodies are localized all over the secondary wall of fibers. PGA/RG-I epitopes, but not RG-II epitopes, are also present in the middle lamellae and cell junctions. In marked contrast, β-(1→4) galactans recognized by the LM5 monoclonal antibody and AGP epitopes recognized by anti-β-(1→6) galactan and LM2 antibodies are primarily located in the half of the secondary wall nearest the plasma membrane. LM2 epitopes, present in 1-week-old fibers, are undetectable later in development, suggesting a regulation of the expression of certain AGP epitopes. In addition, localization of cellulose with the cellobiohydrolase I-gold probe reveals distinct subdomains within the secondary walls of young fibers. These findings indicate that, in addition to cellulose, early-developing flax fibers synthesize and secrete different pectin and AGP molecules.
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  • 19
    ISSN: 1615-6102
    Keywords: Arabidopsis thaliana ; Cryopreservation ; Dehydration ; Thermal analysis ; Sucrose ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Arabidopsis thaliana suspension cells were preserved in liquid nitrogen for over three years, using embedding of cells in calcium-alginate prior to subculture in sucrose-enriched medium, air-drying, and direct quenching in liquid nitrogen. Survival of cells reached 34%, yielding regrowth at the surface of all cryopreserved beads in less than 7 days. Following pretreatment and dehydration, the water content dropped from 2300% to 34% with respect to dry weight. Differential scanning calorimetry showed that glass transition occurred on cooling, followed by a slight crystallization event on rewarming. The survival of cells was independent of the cooling rate. The tolerance of the acute dehydration step increased progressively with sucrose pretreatment duration, indicating the requirement for adaptative cellular alterations. Ultrastructural studies revealed several changes in cells after sucrose pretreatment prolonged from 1 to 7 days: reversal of the initially plasmolyzed state, microvacuolation, numerous autophagic structures, scarcity of ribosomes, increase in number and size of starch grains. No cell division seemed to occur during this period. After air-drying and after a freeze-thaw cycle, followed by 24 h rehydration, regenerating cells had recovered a high level of ultrastructural organization and contained numerous polysomes suggesting an intense metabolic activity. Trehalose, a cryoprotective disaccharide not considered to be a metabolic substrate, yielded only 70% regrowth after freezing. Biochemical analysis showed that soluble sugars accumulated during the pretreatment, essentially sucrose or trehalose; the monosaccharide content also increased. In the light of these results, the action of sucrose in inducing freezing tolerance is discussed.
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  • 20
    ISSN: 1615-6102
    Keywords: Beta vulgaris ; Cyst nematodes ; Histology ; Resistance mechanism ; Syncytium ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Using susceptible and resistant sugar beet lines, comparative analyses of root histology and ultrastructure were made during invasion by nematodes and the induction and formation of specific feeding structures (syncytia).The resistant line carried the resistance geneHs1pro−1.Nematodes were able to invade and induce functional syncytia in roots of resistant and susceptible lines. However, syncytia in resistant roots were smaller and less hypertrophied. The vacuolar system of syncytia in susceptible plants contained many small vacuoles. In resistant plants vacuoles were larger but less numerous. Smooth endoplasmic reticulum prevailed in syncytial protoplasts of susceptible plants, whereas almost only rough endoplasmic reticulum occurred in syncytia in resistant plants. The most conspicuous and hitherto undescribed trait of syncytia in resistant roots was the initial appearance of loose, and later compact, aggregations of the endomembrane system which composed most of the endoplasmicreticulum system of syncytia at later stages. Syncytia in resistant plants usually degraded before the nematodes reached their adult stage. The appearance of membrane aggregations and the other resistance-specific features are discussed in relation to their possible effects on syncytium function and role in nematode resistance.
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  • 21
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    Protoplasma 211 (2000), S. 94-102 
    ISSN: 1615-6102
    Keywords: Androgenesis ; Embryogenesis ; Microspore culture ; Pollen ; Ultrastructure ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have made a detailed cytological examination of the development of wheat embryoids, monitoring their initial divisions from two to ten cells by both light and electron microscopy. According to our observations the first embryogenic division is symmetrical. After the androgenesis induction treatment, there is a decrease in ribosome population with cells that have inactive nucleoli made up almost exclusively of a dense fibrillar component. This population is restored after initial embryogenic divisions. During the initial divisions the embryogenic pollen grains do not appear to change in size and the pollen wall remains intact. The exine undergoes no modification but the intine thickens, and we have observed that the thickness of the intine can be used as a cytological marker of androgenesis. The walls separating the cells obtained after embryogenic division contained numerous plasmodesmata. The beginnings of embryo polarization and cell differentiation could be made out in the very early pollen embryoids.
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  • 22
    ISSN: 1615-6110
    Keywords: Angiosperms ; Campanulaceae ; Wahlenbergia ; Breeding system ; pollination ; pollen collecting hairs ; autogamy ; self-compatibility ; nectar ; island biology ; Juan Fernández Islands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The reproductive biology ofW. berteroi, W. fernandeziana, and a putative hybrid betweenW. fernandeziana andW. grahamiae, endemic to Robinson Crusoe Island (Juan Fernández archipelago, Chile) was studied. Flowers are hermaphroditic, protandrous, offer nectar, and exhibit secondary pollen presentation involving pollen collecting hairs on the style. These features imply allogamy and biotic pollination. However, male and female phases overlap and no effective pollinators were observed. Experimental data indicate these taxa are self-compatible and facultatively autogamous, a conclusion also suggested by the pollen/ovule ratios. Selfing is accomplished when the stigmatic lobes reflex and touch the style, except forW. berteroi where they do not reflex completely. Autogamy is accomplished in the latter when pollen grains deposited on the inner surface of the corolla throat by the “pollen brush” are gathered by stigmatic lobes when shaken by wind. The degree of autogamy, and perhaps self-compatibility, seems to be inconstant, as implied by the variable natural seed set (overall range 21–188 seeds per fruit). A mixed mating system — primarily outcrossing/entomophilous, but also autogamous — must have been present in the continental ancestors of these taxa. Autogamy promoting self-fertilization is important now — on an island with scarce pollinators — and in the past — when the first founders arrived.
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  • 23
    ISSN: 1615-6102
    Keywords: Glutathione ; Root ; Chromosomal aberration ; Ultrastructure ; Picea abies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Young spruce seedlings (Picea abies [L.] Karst.) grown in hydroponic culture were exposed to three different concentrations (50,100, and 500 μM) of reduced glutathione for 24 h. These physiologically relevant concentrations of glutathione had a multiple effect on the investigated tissue. Feeding of glutathione to roots increased the concentrations of thiols (glutathione, cysteine, and γ-glutamyl-cysteine) in roots, decreased the rate of cell divisions, induced mitotic abnormalities, and affected the cell ultrastructure. Electron micrographs showed effects such as advanced vacuolation, dilated rough-endoplasmic-reticulum cisternae, and separations of the plasma membrane from the cell wall.
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  • 24
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    Plant systematics and evolution 222 (2000), S. 1-17 
    ISSN: 1615-6110
    Keywords: Angiosperms ; pollen ; pollen wall ; pollination ; exine ; intine ; aperture ; ornamentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Qualities of the stratified pollen walls were evaluated for their possible role in pollination (pollination modes, and pollen tube formation). The importance of studying pollen grains in their respective natural state is noted. Examples of pollen morphological features specific to pollination vectors are rare and difficult to demonstrate. However, some complex, but significant correlations are reported.
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  • 25
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    Plant systematics and evolution 222 (2000), S. 281-292 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Echium ; Esterhazya ; pollination ecology ; anthers ; pollen ; secondary pollen presentation ; sporopollenin ; viscin threads
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This paper reviews the origin, nature, systematic distribution, and the respective function of the highly variable and diverse thread-forming structures in angiosperm anthers (including somewhat similar, rare features in ferns and gymnosperms). On one hand, such threads may function as pollen-connecting vectors in forming pollen dispersal units, as sporopollenin threads (viscin threads), e.g. in Onagraceae, or sporopollenin-less threads in surprisingly many other angiosperm families. On the other hand, as is known from theImpatiens — “pollen basket”, threads or ropes may be involved in pollen presentation. In addition, for the first time two new examples of “pollen baskets” in Boraginaceae and Scrophulariaceae are reported. InEchium the basket is formed by cellular elements from the modified septal regions, whereas inEsterhazya a similar effect is achieved in an analogous manner by trichomes of the epidermal layer of the thecal wall. There is obviously a different function of these seemingly very similar baskets: inEchium the feature acts preferably as a pollen presentation agent, whereas inEsterhazya the primary function is to prevent all the pollen from being dispersed too soon.
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  • 26
    ISSN: 0219-1032
    Keywords: Calcium-binding Protein ; Immunocytochemistry ; Localization ; Visual Cortex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The distribution and morphology of neurons containing three calcium-binding proteins, calbindin D28K, calretinin, and parvalbumin in the adult rabbit visual cortex were studied. The calcium-binding proteins were identified using antibody immunocytochemistry. Calbindin D28K-immunoreactive (IR) neurons were located throughout the cortical layers with the highest density in layer V. However, calbindin D28K-IR neurons were rarely encountered in layer I. Calretinin-IR neurons were mainly located in layers II and III. Considerably lower densities of calretinin-IR neurons were observed in the other layers. Parvalbumin-IR neurons were predominantly located in layers III, IV, V, and VI. In layers I and II, parvalbumin-IR neurons were only rarely seen. The majority of the calbindin D28K-IR neurons were stellate, round or oval cells with multipolar dendrites. The majority of calretinin-IR neurons were vertical fusiform cells with long processes traveling perpendicularly to the pial surface. The morphology of the majority of parvalbumin-IR neurons was similar to that of calbindin D28K: stellate, round or oval with multipolar dendrites. These results indicate that these three different calcium-binding proteins are contained in specific layers and cells in the rabbit visual cortex.
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  • 27
    ISSN: 1432-041X
    Keywords: Major haemolymph proteins ; Development ; Cuticle ; Immunocytochemistry ; Ceratitis capitata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The developmental profile of the major haemolymph proteins (ceratitins) inCeratitis capitata was studied. Ceratitin concentration in the haemolymph decreases dramatically during the last days of pupal life, while the amounts of ceratitins in whole organism extracts remain unchanged. By electrophoretic, immunological and immunofluorescence techniques it was revealed that ceratitins are reabsorbed by the fat body and a fraction of them is deposited in the cuticle. The possible role of ceratitins is discussed.
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  • 28
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    Calcified tissue international 36 (1984), S. 550-555 
    ISSN: 1432-0827
    Keywords: Enamel crystals ; Length ; Shape ; Apatite ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary An original method for fractionating and preparing isolated crystals of homogeneous size was developed. It was demonstrated that enamel apatite crystals are at least 100 µm long. The flexibility of the very long crystallites was demonstrated. Crystal curvatures, accounting for the irregular course of the prisms through the enamel thickness, were visualized and measured. It was shown that in the deep forming enamel layer, lateral branches may grow out of the crystals and crystal fusing often occurs, inducing the crystallites to assume pyramidal shapes with their wide bases pointing toward the dentino-enamel junction and one or two tops toward Tomes' processes. During the maturation process, the two tops of the still immature crystals also fuse so that the mature crystals acquire a rodlike aspect, with parallel faces and steplike graduations along thec axis, allowing a close contact between the crystals. These results support the hypothesis that the crystallites would be continuous from the dentino-enamel junction to the surface.
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  • 29
    ISSN: 1432-2048
    Keywords: Immunocytochemistry ; Lectin (localization) ; Phaseolus (lectin) ; Phytohemagglutinin ; Seed (lectin)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have examined the properties and subcellular localization of phytohemagglutinin (PHA), the major lectin of the common bean (Phaseolus vulgaris.), in the axis cells of nearly mature and imbibed mature seeds. On a protein basis the axis contained about 15% as much PHA as the cotyledons. Localization of PHA was done with an indirect immunolabeling method (rabbit antibodies against PHA, followed by colloidal gold particles coated with goat antibodies against rabbit immunoglobulins) on ultra-thin cryosections which were embedded in plastic on the grids after the immunolabeling procedure. The embedding greatly improved the visualization of the subcellular structures. The small (4 nm) collodial gold particles, localized with the electron microscope, were found exclusively over small vacuoles or protein bodies in all the cell types examined (cortical parenchyma cells, vascular-bundle cells, epidermal cells). The matrix of these vacuoles-protein bodies appears considerably less dense than that of the protein bodies in the cotyledons, but the results confirm that in all parts of the embryo PHA is localized in similar structures.
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  • 30
    ISSN: 1432-072X
    Keywords: Methanogenium tatii ; Ultrastructure ; Physiology ; Glycoproteins ; DNA-DNA Homology ; Taxonomy ; Archaebacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new coccoid methanogen, Methanogenium tatii, was isolated and characterized. The mesophilic isolate can grow on and produce methane from H2:CO2 and formate. For growth acetate is strictly required. The cell shape, the G+C content of 54 mol% and DNA-DNA homology data suggest it to be a Methanogenium species.
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  • 31
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    Archives of microbiology 138 (1984), S. 229-232 
    ISSN: 1432-072X
    Keywords: Actinomycetes ; Streptomyces torulosus ; Morphology ; Ultrastructure ; Verrucate spores ; Knobby ornamentation ; Sheath
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The type strain of Streptomyces torulosus Lyons and Pridham (1971) was studied by scanning- and transmission electron microscope. Spore chains were formed in spirals by aerial mycelium. The spores were connected by nozzles in which small channels could be observed. The knobby ornamentations of the spores arised on a thin fibrous sheath, enveloping the spore chains. These irregular blunt projections, called knobs, had varying diameters of 100 to 250 nm. The base of the knob, consisting of globose to flattened electron dense material, was sitting directly on the sheath. It was covered by several small vesicles of the same material. Each hollow vesicle beared a thin bowlshaped shell of electron transparent material. In general, the cupular bowls and their supporting vesicles became easily depressed on their base, but not detached from the surface of the spores. This type of knobby spore ornamentation was suggested to be designated as a verrucate spore type.
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  • 32
    ISSN: 1432-072X
    Keywords: Nitrobacter hamburgensis ; Nitrite oxidoreductase ; Nitrate reductase ; Molybdenum iron-sulfur protein ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrite oxidoreductase, the essential enzyme complex of nitrite oxidizing membranes, was isolated from cells of the nitrifying bacterium Nitrobacter hamburgensis. The enzyme system was solubilized and purified in the presence of 0.25% sodium deoxycholate. Nitrite oxidoreductase oxidized nitrite to nitrate in the presence of ferricyanide. The pH optimum was 8.0, and the apparent K m value for nitrite amounted to 3.6 mM. With reduced methyl-and benzylviologen nitrite oxidoreductase exhibited nitrate reductase activity with an apparent K m value of 0.9 mM for nitrate. NADH was also a suitable electron donor for nitrate reduction. The pH optimum was 7.0. Treatment with SDS resulted in the dissociation into 3 subunits of 116,000, 65,000 and 32,000. The enzyme complex contained iron, molydbenum, sulfur and copper. A c-type cytochrome was present. Isolated nitrite oxidoreductase is a particle of 95±30 Å in diameter.
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  • 33
    ISSN: 1432-234X
    Keywords: Ultrastructure ; Gills ; Epithelial cells ; Polychaeta
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    Topics: Biology
    Notes: Summary The ultrastructure of gill epidermal cells of Diopatra neapolitana and their relationship with blood spaces are described. The existence of a basal infolding complex, related to the blood spaces, is also reported. A possible involvement of these cells in osmoregulation and ion interchange, apart from their well-known role in respiration, is suggested.
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  • 34
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    Theoretical and applied genetics 68 (1984), S. 305-309 
    ISSN: 1432-2242
    Keywords: Impatiens ; Microspore mitosis ; Plastid distribution ; Ultrastructure
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    Topics: Biology
    Notes: Summary This paper describes the unequal distribution of plastids in the developing microspores of Impatiens walleriana and Impatiens glandulifera which leads to the exclusion of plastids from the generative cell. During the development from young microspore to the onset of mitosis a change in the organization of the cytoplasm and distribution of organelles is gradually established. This includes the formation of vacuoles at the poles of the elongate-shaped microspores, the movement of the nucleus to a position near the microspore wall in the central part of the cell, and the accumulation of the plastids to a position near the wall at the opposite side of the cell. In Impatiens walleriana, the accumulated plastids are separated from each other by ER cisterns, and some mitochondria are also accumulated. In both Impatiens species, the portion of the microspore in which the generative cell will be formed is completely devoid of plastids at the time mitosis starts.
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  • 35
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    Cell & tissue research 235 (1984), S. 309-318 
    ISSN: 1432-0878
    Keywords: Ascidian ; Gut ; Cell involution ; Ultrastructure ; Phagocytes
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    Topics: Biology , Medicine
    Notes: Summary Degenerative changes in the digestive tract of zooids of Botryllus schlosseri were studied by light and electron microscopy. Three main processes occurred in the tissues: contraction, involution and phagocytosis. The contraction of epidermis and peribranchial epithelium in which cytoplasmic microfilaments probably participate, seemed to have a special role in compressing the underlying organs. During contraction most of the body cavities collapsed, the branchial walls disintegrated and the fragments were rapidly taken up by large phagocytes. The gut epithelium retained its apparent continuity longer, though isolated phagocytes infiltrated it to eliminate single cells. Cell degeneration came about chiefly either through swelling and lysis of cells or through loss of water and condensation of cytoplasm and nucleus. The fate of all regressed tissues was to be engulfed and digested by wandering phagocytes. However, it was also observed that numerous cells of different epithelia could act as fixed phagocytes by engulfing cell debris and entire cells into heterophagic vacuoles.
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  • 36
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    Cell & tissue research 235 (1984), S. 347-356 
    ISSN: 1432-0878
    Keywords: Blastocyst ; Ultrastructure ; Pig
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    Topics: Biology , Medicine
    Notes: Summary Between days 8 and 11 of pregnancy spherical blastocysts from 0.3 to 10 mm in diameter were flushed from the uterine horns of Dutch Landrace pigs. A description of their ultrastructure is given, and the uptake of horseradish peroxidase and ferritin is demonstrated. The ultrastructure of the trophoblast was similar at all ages studied. The trophoblast which has many apical microvilli is able to take up and digest the macromolecules which were offered in the in vitro incubation medium. The hypoblast consists of flattened cells. In blastocysts 2 mm and larger, compact cells bearing microvilli are found below the embryoblast. Cell organelles indicating protein synthesis are found within hypoblast cells of such blastocysts. In the embryoblast, local concentrations of cell organelles are visible, indicating that differentiation has started. After the disappearance of Rauber's layer, which takes place when the blastocyst reaches a diameter of about 2 mm, superficial embryoblast cells develop short microvilli. The cells do not absorb ferritin or peroxidase but are dependent on the trophoblast for their food requirements. All cell layers in the blastocyst contain mitochondria that have characteristics of those found in steroidproducing cells. The significance of the uptake and digestion of macromolecules by trophoblast cells, the synthesis of protein by hypoblast cells and the possible synthesis of steroids is discussed with respect to the relationship between the cell layers of the blastocyst and in the context of conceptomaternal relationships.
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  • 37
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    Cell & tissue research 236 (1984), S. 365-372 
    ISSN: 1432-0878
    Keywords: Skeletal muscles ; Myofibrils ; Ultrastructure ; Exertion ; Man
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    Topics: Biology , Medicine
    Notes: Summary The fine structure of muscle fibres from m. vastus lateralis of nine healthy males (mean age 26 years) was investigated. Four individuals constituted non-exercised controls while five subjects participated in a two-months eccentric muscular training program. Specimens from the controls showed a well-preserved, regular myofibrillar band pattern while changes in the myofibrillar architecture were constantly found in specimens taken after the training program. These changes consisted of Z-band alterations, Z-bands being out of register, extra sarcomeres, Z-band extensions and bisected Z-bands. Between the separated Z-band halves, thin and thick myofilaments as well as abundant glycogen particles and/or ribosomes, were observed. Type-2 (fast-twitch) fibres were predominantly affected. Contrary to the controls the trained individuals constantly showed a greater variation in sarcomere lengths in Type-2 fibres than in Type-1 fibres. It is concluded that muscular work of high tension can induce fine-structural alterations. When repeated over a long period of time, extreme tension demands seem to initiate reorganization in the muscle fibres, predominantly in the, ultrastructurally defined, Type-2 fibres. This adaptation probably results in a better stretchability of the muscle fibres, reduces the risk for mechanical damage and brings about an optimal overlap between actin and myosin filaments.
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  • 38
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    Cell & tissue research 236 (1984), S. 393-397 
    ISSN: 1432-0878
    Keywords: Smooth muscle ; Salamander, Amphiuma ; Ultrastructure ; Stereology ; Volume: surface area ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An ultrastructural and stereological examination was performed on stomach smooth muscle of the salamander Amphiuma. This tissue has very large cells, ranging up to 12×1500 μm when relaxed. The extracellular space is 31% of the tissue volume, and the tissue contains 84.6% water. These values are similar to those of other amphibian and mammalian gastrointestinal smooth muscle. The cells possess the usual smooth muscle organelles. Thick, thin and intermediate filaments are present, along with membrane-associated and cytoplasmic dense regions. There is a well-developed sarcoplasmic reticulum and many microtubules. Caveolae are found in rows along the cellular surface; the caveolae increase the cellular surface area by about 70%. The ratio mean volume: surface area of the cells is 1.26 μm. This tissue appears to be typical of gastrointestinal smooth muscle, with the exception of the very large size of the cells.
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  • 39
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    Cell & tissue research 236 (1984), S. 619-628 
    ISSN: 1432-0878
    Keywords: Gastrotricha, freshwater ; Sperm, reduced ; Ultrastructure ; Spermatogenesis ; Temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Spermatogenesis and spermiogenesis in Lepidodermella squammata are confined to the postparthenogenic phase of the life cycle and coincide with developmental changes in the bilateral female gonads. Male stages are bilateral but asynchronous, in the lateral abdomen anterior to the female gonads. Maximum observed sperm production is two packets per side, or 64 sperm. Sperm formation occurs more rapidly at 27° C than at 20° C (p〈0.001), requiring as little as 1 day. Two spermatogonial mitotic divisions produce a clone of four primary spermatocytes connected by bridges (stage 1). Centrioles are absent. Development occurs within a cyst. Meiotic divisions produce 16 spermatids (stage 2), each containing a dense, elongate, tapered nucleus. Cytoplasmic membranes enclose one end of the nuclear rod, excluding all other organelles. Completion of this process results in stage 3, a packet of 16 sperm associated with one dense sphere, a modified ‘residual body’ containing cytoplasmic debris. The residual body then disappears, leaving the sperm packet of stage 4. Each mature sperm is a dense nuclear rod with surrounding membranes, lacking acrosome, mitochondrion, centrioles, and flagellum. Function of sperm has not been demonstrated. The spermatozoa are of a reduced type not previously described.
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  • 40
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    Cell & tissue research 236 (1984), S. 629-636 
    ISSN: 1432-0878
    Keywords: Oocytes, primary ; Gastrotricha, freshwater ; Ultrastructure ; Synaptonemal complex ; X-body
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    Topics: Biology , Medicine
    Notes: Summary Six small cells are present in each of the bilateral gonads of parthenogenically reproductive Lepidodermella squammata. Early in the extended postparthenogenic phase of the life history, these cells undergo limited proliferation followed by differentiation. Primary oocytes of three types are present 0.3 days after deposition of the final parthenogenic egg: small oocytes with presynaptic nuclei; intermediate oocytes with nuclei containing synaptonemal complexes; and larger oocytes with a germinal vesicle. Oocytes persist without further development at least until day four of the postparthenogenic phase. Older isolated animals may contain and even deposit an enlarged egg, but successful progeny does not result. Oocytes are located at the anterior pole of each of the bilateral gonads, adjacent to developing male tissues producing sperm. More posterior cells in the gonad are initially undifferentated in the postparthenogenic phase. Dorsal and central cells first show specialization for secretory activity, and by day four contain peripheral layers of RER and central accumulations of polymorphic secretion droplets. The posterior and ventral cells produce secretion droplets that aggregate into an enlarging bilobed structure called the X-body. Two or three cells in each gonad contribute secretions to the X-body, which is intracellular in a secondary syncytium formed by the contributing cells. Functions for the postparthenogenic gametes and for the X-body are not yet demonstrated.
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  • 41
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    Cell & tissue research 236 (1984), S. 693-697 
    ISSN: 1432-0878
    Keywords: Intermediate filaments ; Microtubules ; Caveolae ; Bullfrog ; Arachnoid mater ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the bullfrog, the meninges surrounding the central nervous system include an arachnoid mater that contains layers of cells with abundant intermediate filaments (IFs) having unique organizational characteristics. This membrane contains an inner lamina of cells that resemble fibroblasts and an outer lamina of flattened cells that are almost filled with IFs. The IFs of the outer arachnoid are arranged in compact, arching bundles that lie parallel to the outer surface of the central nervous system. Thus, sections cut tangentially to the membrane reveal bending of filament bundles, whereas transverse sections do not. In some cells bordering the subdural space, bundles of filaments are organized into highly-ordered spiral arrays. Attachments to the numerous desmosomes and, apparently, to the nuclear envelope suggest anchoring of cytoplasmic structures by the IF system. Microtubules occur primarily near the plasma membrane and the nucleus. Numerous caveolae also are associated with the plasma membrane. The unusual abundance, organization, and cytoplasmic relations of IFs in the bullfrog arachnoid suggest that this membrane may serve as an important model for study of fundamental cytoskeletal relations and function.
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  • 42
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    Cell & tissue research 237 (1984), S. 195-202 
    ISSN: 1432-0878
    Keywords: Pituitary ; Prolactin cells ; Estrogen ; Heterogeneity ; Immunocytochemistry
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    Topics: Biology , Medicine
    Notes: Summary This study was conducted to determine the functional and/or developmental relationships among three heterogeneous types of prolactin cells (I, II and III) in rats. Rats were injected subcutaneously daily with estradiol or testosterone propionate on days 10–20 after birth. Estradiol increased the proportion of cell types II and III, increased serum PRL levels 12-fold in males and 15-fold in females, and increased pituitary levels of prolactin 12-fold in males and 5-fold in females. Testosterone mainly increased the proportion of the Type-II cells, decreased serum levels of prolactin in males only, and did not change pituitary levels of prolactin. In a second experiment, treatment of rats with nafoxidine for five days after E2 treatment (days 10–20 after birth) increased the proportion of Type-I cells and decreased the proportion of Type-III cells and decreased serum and pituitary levels of prolactin by 50% in females and by 15 and 45% in males. In a third experiment utilizing adult male rats, estradiol and testosterone were found to modulate the relative ratios of the different types of PRL cells as they did in immature animals. The data taken as a whole suggest the possibility of an estrogen-stimulated conversion of one cell type to another, which may be a reflection of prolactin secretory activity.
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  • 43
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    Cell & tissue research 237 (1984), S. 245-252 
    ISSN: 1432-0878
    Keywords: Pineal organ ; Interstitial cells ; Astrocytes ; Immunocytochemistry ; Rat ; Mouse
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    Topics: Biology , Medicine
    Notes: Summary Antigenic markers characteristic of astrocytes and their differentiative states (i.e., glial fibrillary acidic protein (GFAP), vimentin, and M1 and C1 antigens) were investigated in the pineal gland of mouse and rat using double immunolabeling techniques. In both species the socalled interstitial cells as characterized by TEM were shown to be astrocytes, since they expressed vimentin, but neither fibronectin (a marker for fibroblasts and endothelial cells) nor the neuron-specific L1 antigen or tetanus toxin receptors. Subpopulations of vimentin-positive pineal astrocytes were also GFAP- and C1- antigen-positive. M1- antigenpositive cells were not detected. It is concluded that a considerable proportion of interstitial cells in the pineal gland of rat and mouse are immature astrocytes which, in contrast to other parts of the central nervous system, persist into adulthood.
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  • 44
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    Cell & tissue research 237 (1984), S. 277-284 
    ISSN: 1432-0878
    Keywords: Swimbladder ; Teleost ; Cholinergic nerves ; Adrenergic nerves ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The general structure, ultrastructure and innervation of the swimbladder of the smooth toadfish, Tetractenos glaber, were examined with light-microscopic, fluorescence-histochemical, and transmission electron-microscopic techniques. The structure of the swimbladder is similar to that of other euphysoclists. Fluorescence histochemistry showed adrenergic fibres in both the secretory and resorptive areas of the swimbladder. Transmission electron microscopy revealed two morphologically distinct axon profiles type-I profiles containing many small, flattened vesicles; type-II profiles containing both large, granular vesicles and rounded, small clear vesicles in varying proportions. The gas-gland cells and surrounding muscularis mucosae are innervated by both type-I and type-II fibres. Type-I fibres also innervate pre-rete arteries. The rete- and gas-gland capillaries do not appear to be innervated. Arteries running to the resorptive area are innervated by type-I fibres. Both type-I and type-II profiles make contact with the muscularis mucosae in the resorptive area. Only type-I fibres innervate the radial dilator muscle in the oval sphincter region, whereas only type II fibres innervate the circular muscle of the oval sphincter. Type-I fibres took up α-methyl-noradrenaline, and could not be found after pre-treatment with 6-hydroxydopamine. They are, therefore, assumed to be adrenergic. Type-II fibres were tentatively identified, by exclusion, as cholinergic.
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  • 45
    ISSN: 1432-0878
    Keywords: Subcommissural organ ; Reissner's fiber ; Ependyma ; Secretory process ; Comparative analysis ; Immunocytochemistry ; Vertebrates
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    Topics: Biology , Medicine
    Notes: Summary The subcommissural organs (SCO) of 76 specimens belonging to 25 vertebrate species (amphibians, reptiles, birds, mammals) were studied by use of the immunoperoxidase procedure. The primary antiserum was obtained by immunizing rabbits with bovine Reissner's fiber (RF) extracted in a medium containing EDTA, DTT and urea. Antiserum against an aqueous extract of RF was also produced. The presence of immunoreactive material in cell processes and endings was regarded as an indication of a possible route of passage. Special attention was paid to the relative development of the ventricular, leptomeningeal and vascular pathways established by immunoreactive structures. The SCO of submammalian species is characterized by (i) a conspicuous leptomeningeal connection established by ependymal cells, (ii) scarce or missing hypendymal cells, and (iii) a population of ependymal cells establishing close spatial contacts with blood vessels. The SCO of most mammalian species displays the following features: (i) ependymal cells lacking immunoreactive long basal processes, (ii) hypendymal secretory cells occurring either in a scattered arrangement or forming clusters, (iii) an occasional leptomeningeal connection provided by hypendymal cells, and (iv) in certain species numerous contacts of secretory cells with blood vessels. In the hedgehog immunoreactive material was missing in the ependymal formation of the SCO, but present in hypendymal cells and in the choroid plexuses. The SCO of several species of New-and Old-World monkeys displayed immunoreactive material, whereas that of anthropoid apes (chimpanzee, orangutan) and man was completely negative with the antisera used.
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  • 46
    ISSN: 1432-0878
    Keywords: Subcommissural organ ; Ependyma ; Comparative aspects ; Immunocytochemistry ; Secretory process ; Blood vessels
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    Notes: Summary In 76 specimens (amphibians, reptilians, mammals) belonging to 25 different vertebrate species, the region of the subcommissural organ (SCO) was investigated with the use of a primary antiserum raised against an extract of bovine Reissner's fiber+the immunoperoxidase procedure according to Sternberger et al. (1970). In the SCO of a toad (Bufo arenarum) and several species of reptiles (lacertilians, ophidians, crocodilians), the ependymal cells were the only type of secretory cell displaying vascular contacts, whereas in mammals ependymal and hypendymal cells established intimate spatial contacts with blood vessels. In Bufo arenarum, but especially in the reptilian species examined, the ependymo-vascular relationship was exerted by a population of ependymal cells having a rather constant location within the SCO and projecting to capillaries that showed a remarkably constant pattern of anatomical distribution. In the SCO of mammals the modality and degree of the structural relationships between secretory cells and blood vessels varied greatly from species to species. In the SCO of the armadillo and dog the secretory tissue was organized as a thick, highly vascularized layer with most of the cells oriented toward the capillaries. A rather opposite situation was found in the SCO of New-and Old-World monkeys, where vascular contacts were restricted to a few ependymal cells.
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  • 47
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    Cell & tissue research 237 (1984), S. 521-524 
    ISSN: 1432-0878
    Keywords: α-Melanocyte-stimulating hormone ; α-MSH-like peptide ; Immunocytochemistry ; Hypothalamus ; Lizard (Lacerta muralis)
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    Topics: Biology , Medicine
    Notes: Summary The distribution of α-melanocyte-stimulating hormone (α-MSH) was studied in the brain of the lizard Lacerta muralis by means of immunocytochemical staining methods. α-MSH-like containing cells were found in the ventro-lateral preoptic area and the paraventricular and supraoptic nuclei. Some scattered cells staining for α-MSH were also detected in the mesencephalo-diencephalic boundary region, while numerous α-MSH-like nerve fibres were localized in the medial eminence. No reaction was observed after the use of antiserum preabsorbed with synthetic antigen. These findings suggest that an α-MSH-like peptidergic system could possibly be involved in the hypothalamo-hypophysial regulation and/or play a role as neurotransmitter in this animal.
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  • 48
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    Cell & tissue research 237 (1984), S. 537-547 
    ISSN: 1432-0878
    Keywords: Scale ; Regeneration ; Ultrastructure ; Cichlid ; Hemichromis bimaculatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Scale regeneration has been studied in Hemichromis bimaculatus. The removed scale, which serves as a control, is covered by its surrounding scleroblasts as can be seen with scanning electron microscopy. Subsequently, during regeneration, a population of scleroblasts arises in the empty dermal pocket as shown with transmission electron microscopy. At first, an elongated papilla of regeneration forms, probably from the differentiation of dermal fibroblasts. A scale anlage composed of the osseous layer appears in the middle of the papilla, which becomes a regenerating bag. All the surrounding large scleroblasts are involved in scale formation, although later three populations of scleroblasts specialize according to their location around the scale. Superficial scleroblasts flatten when the final thickness of the osseous layer of the scale is attained; the deep scleroblasts are responsible for the formation of the basal plate whereas marginal scleroblasts increase the diameter of the osseous layer of the scale. During scale regeneration, scleroblasts are more numerous and larger than during scale ontogenesis. In particular, deep scleroblasts form a columnar epithelium when the basal plate is laid down, a feature which is not found during scale ontogenesis. Moreover, the regenerated basal plate exhibits an orthogonal “plywood” arrangement that is never seen in the embryonic scale where the “plywood” is of the intermediate type.
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  • 49
    ISSN: 1432-0878
    Keywords: Epididymis (marsupials) ; Ultrastructure ; Sperm maturation
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    Notes: Summary The ductus epididymidis of the tammar is lined by an epithelium composed of principal, mitochondria-rich, apical and basal cells, and intraepithelial leucocytes. The epithelium is structurally differentiated into 6 zones referred to as the initial segment, middle segment (3 subdivisions) and terminal segment (2 subdivisions). The occurrence of the initial, middle and terminal segments corresponds quite closely to the anatomical differentiation of the epididymis into a head, body and tail. The initial segment epithelium in the tammar is lower and has shorter and more slender stereocilia than in other mammals which have been described. Otherwise, the structure of the epithelium has similar characteristics in the tammar to that described in other mammals. Spermatozoa begin to develop the capacity for motility within the initial segment, but only show structural signs of maturation in the middle segment. The sperm head rotates through 90 degrees in the proximal subdivision of the middle segment. The cytoplasmic droplet is detached and spermatozoa develop the capacity for motility in the middle subdivision of the middle segment. The cytoplasmic droplets are phagocytosed by the epididymal epithelium of the middle segment. Sperm storage appears to be the main function of the terminal segment.
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  • 50
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    Cell & tissue research 238 (1984), S. 203-205 
    ISSN: 1432-0878
    Keywords: Neuropeptide Y ; Hypothalamus, human ; Immunocytochemistry ; Pituitary stalk
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    Topics: Biology , Medicine
    Notes: Summary In order to study the distribution of neuropeptide Y-like immunoreactivity in the human hypothalamus, an immunocytochemical localization of this peptide was performed. Using antibodies developed against synthetic porcine neuropeptide Y (NPY), we have been able to localize immunoreactivity in neuronal cell bodies located exclusively in the infundibular nucleus. Immunostained fibers were found in several regions in the hypothalamus with a high concentration in the periventricular areas. Fibers were also found in the neurovascular zone of the median eminence, the pituitary stalk and the posterior pituitary. These results suggest that immunoreactive material related to porcine NPY is present in the human hypothalamus, with a distribution similar to that observed in the rat.
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  • 51
    ISSN: 1432-0878
    Keywords: Peptidergic neurotransmission ; Lymnaea stagnalis ; Immunocytochemistry ; Ultrastructure
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    Notes: Summary Three neuronal systems of the pond snail Lymnaea stagnalis were immunocytochemically investigated at the ultrastructural level with the unlabeled peroxidase-antiperoxidase technique. Preliminary electrophysiological and cell-filling investigations have shown that a cluster of neurons which reacts positively with an antiserum against the molluscan cardio-active peptide FMRFamide, sends axons to the penis retractor muscle. In this muscle anti-FMRF-amide (aFM) positive axons form neuro-muscular synapses with (smooth) muscle fibers. The morphological observations suggest the aFM immunoreactive system to be involved in peptidergic neurotransmission. In the right parietal ganglion a large neuron (LYAC) is penetrated by aFM positive axons which form synapse-like structures (SLS) with the LYAC. The assumption that the SLS represent the morphological basis for peptidergic transmission is sustained by the observation that iontophoretical application of synthetic FMRFamide depolarizes the LYAC. The axons of a group of pedal anti-vasopressin (aVP) positive cells run in close vicinity to the cerebral ovulation (neuro-)-hormone producing cell system (CDC system) Synapses or SLS between the two systems were not observed. The fact that (bath) application of arg-vasopressin induces bursting in the CDC, may indicate that the vasopressin-like substance of the aVP cells is released non-synaptically.
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  • 52
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    Keywords: Photoperiods ; Pituitary gland, pars tuberalis ; Ultrastructure ; Phodopus sungorus
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    Notes: Summary Conspicuous cytological differences are found between specific secretory cells of the hypophysial pars tuberalis of Djungarian hamsters exposed to long and short photoperiods. The cells differ with respect to the shapes of perikarya and nuclei and show diverse amounts of secretory granules, lysosome-like bodies and glycogen.
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  • 53
    ISSN: 1432-0878
    Keywords: Pituitary gland, pars anterior (distalis) ; Gonadotrops ; Thyrotrops ; Ultrastructure ; Immunolabeling ; Teleosts
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    Notes: Summary Pituitaries of the African catfish (Clarias lazera) were studied with immunocytochemical methods, at the light-microscopic and ultrastructural levels, for the characterization and localization of gonadotropic and thyrotropic cells. Two immunostaining procedures with the use of different markers were carried out: (i) with peroxidase-antiperoxidase, (ii) with protein A-gold. In routinely stained sections for light microscopy two types of basophils were identified in the proximal pars distalis: (1) large, round, purple cells, and (2) small, angular, light-blue cells. Both types were immunolabeled with antibodies against Clarias α,β-gonadotropin (GTH) and salmon G100-GTH. Only the large basophils were immunolabeled with anti-carp β-GTH, whereas the small basophils were the only cells immunolabeled with anti-human thyrotropin beta subunit (anti-h TSH-β). It was concluded that the large basophils represent the gonadotrops and the small basophils the thyrotrops. At the ultrastructural level the immunostaining of the GTH-cells was confined to three types of inclusions: (i) secretory vesicles, (ii) globules, and (iii) electron-dense, membrane-bound irregular masses. Especially the protein A- gold method, in combination with the use of a highly diluted homologous antiserum, resulted in a distinct localization of GTH. The presence of two types of nerve fibres, synaptically contacting the gonadotrops, is discussed with regard to the presence of a peptidergic (stimulatory) and an aminergic (inhibitory) control of GTH-secretion.
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  • 54
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    Cell & tissue research 238 (1984), S. 497-502 
    ISSN: 1432-0878
    Keywords: D2 glycoprotein ; Adrenal gland ; Immunocytochemistry ; Ultrastructure ; Cell adhesion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural localization of the glycoprotein D2 in rat adrenal gland was investigated using immunohistochemical methods, and D2 localization in cultures of adult bovine chromaffin cells was studied by immunofluorescence. D2 was found to be situated on nerve fibers passing through the adrenal cortex and in the medulla zone, and also on the surface of all chromaffin cells. In addition, it was strongly expressed on the surface of glial (Schwann) cells. Cortical cells were unreactive to the antiserum. In cultures, all adrenalin and noradrenalin [dopamine-β-hydroxylase (DBH)-positive] cells were surface labelled for D2. A less frequent second cell type was recognized in vitro which was DBH negative but D2 positive. Such cells were presumed to be Schwann cells. These data are discussed in terms of the developmental origin of the cells and with regard to the putative functional rôle of D2 in cell adhesion phenomena.
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  • 55
    ISSN: 1432-0878
    Keywords: Lymphocytes ; Phytohemagglutinin stimulation ; Nucleolar organizer region ; Three-dimensional reconstruction ; Ultrastructure ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary The ultrastructural changes in the spatial organization of nucleolar DNA in lymphocytes during phytohemagglutinin (PHA) stimulation was studied in guinea pigs by means of oxidized diaminobenzidine (DAB) at low pH as a differentially contrasting stain for nucleic acids and by the use of reconstruction of serial sections. The extended DNA filaments situated inside the fibrillar area originate from a large aggregation of heterochromatin, which is closely associated with the nucleolus, and from the perinucleolar shell of condensed chromatin. It is suggested that these two distinct regions of chromatin might be associated with different functions.
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  • 56
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    Cell & tissue research 235 (1984), S. 177-186 
    ISSN: 1432-0878
    Keywords: Retinal pigment epithelium ; Myeloid bodies ; Diurnal variation ; Morphometrics ; Ultrastructure ; Lipid metabolism ; Endoplasmic reticulum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Myeloid bodies (MBs) occur in the newt (Notophthalmus viridescens) retinal pigment epithelium (RPE) and are similar to areas of specialized endoplasmic reticulum found in a variety of other cell types. The function of these structures is unknown, although a role in lipid metabolism has been strongly suggested. Random samples from conventionally-fixed and sectioned newt RPE, obtained over a 24-hr cycle (LD 12∶12), were examined by electron microscopy. Myeloid bodies appear as stacks of flattened endoplasmic reticulum-associated saccules which increase in length and number as the RPE accumulates shed outer segment material, prior to increase in the amount of stored lipid. Associations of MBs with the nuclear envelope can be related to this increased length. Myeloid bodies decrease numerically in the cell as phagosomes are removed from the cytoplasm, but a decrease in mean sectional MB area, seen in the light phase, is counteracted in darkness where individual MBs are larger than those found in the light. The total sectional area of MBs within a cell and their mean length varied depending on the lighting condition; differences were also found between eyes after extended periods of continuous light and dark. Ribosomes were found in association with the surfaces of both flattened and circular MBs, but they were consistently more densely associated with the shorter concave surfaces of curved regions. A new hypothesis for MB function is presented, which is concerned with their role in isolating toxic lipids such as retinoids, which are accumulated during phagocytosis of shed outer segment tips, and which are capable of disrupting membrane-bound systems necessary for their eventual metabolism and safe storage.
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  • 57
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    Cell & tissue research 235 (1984), S. 211-214 
    ISSN: 1432-0878
    Keywords: Adenohypophysis ; Pars distalis ; Immunocytochemistry ; Amphibia ; Gymnophiona
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The indirect immunofluorescence method was used to identify and locate LTH-, STH-, LH-, TSH-, ACTH- and MSH-immunoreactive cells in the pituitary of Typhlonectes compressicaudus (Gymnophiona). The present study defines the histological and histochemical staining properties of each cell type identified.
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  • 58
    ISSN: 1432-0878
    Keywords: Caldesmon ; Actin ; Immunocytochemistry ; Small intestine ; Smooth muscle ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of caldesmon (a calmodulin-binding, F-actin-interacting protein) (Sobue et al. 1982) and of actin was studied in the rat's small intestine by means of light-microscopic immunocytochemistry. Positive immunostaining for caldesmon was seen in smooth muscle cells of the intestinal wall, and of blood vessels, and in the apical portion of the absorptive epithelial cells. The immunoreactivity in goblet cells was difficult to recognize. The positive reaction to immunostaining for actin showed almost the same pattern as that for caldesmon. These results suggest that this calmodulin-binding protein may play an important role in the control of actin-myosin interaction in smooth muscle cells and in non-muscle cells.
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  • 59
    ISSN: 1432-0878
    Keywords: FMRFamide ; Bovine pancreatic polypeptide ; Immunocytochemistry ; Peptidergic neurons ; Leptinotarsa decemlineata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Particular neurons in the nervous system of the Colorado potato beetle, Leptinotarsa decemlineata, are recognized by antisera against bovine pancreatic polypeptide and FMRFamide. Both antisera react with the same neurons. Solid phase absorptions showed that antiserum against bovine pancreatic polypeptide cross-reacts with FMRFamide, whereas antiserum against FMRFamide cross-reacts with bovine pancreatic polypeptide. Some of the immunoreactive neurons have axons branching extensively within the neuropile, which suggests that the peptide is used as transmitter. In the corpus cardiacum, a neurohaemal organ in insects, numerous immunoreactive axon terminals are present. Here, the peptide material is presumably released as a hormone.
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  • 60
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    Cell & tissue research 235 (1984), S. 691-693 
    ISSN: 1432-0878
    Keywords: Plasma cells ; Ultrastructure ; Immunology ; Myxinoids
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    Topics: Biology , Medicine
    Notes: Summary Hagfishes, the most primitive vertebrates, are of special interest for the evolution of immune responses. Eptatretus stoutii, the Pacific hagfish, is able to mount cellular and humoral immune responses but all attempts to demonstrate in them the presence of plasma cells have failed. In the present study we demonstrate for the first time plasma cells identifiable by ultrastructural criteria in the pronephros, a primitive lymphohaemopoietic organ, of Myxine glutinosa, the Atlantic hagfish.
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  • 61
    ISSN: 1432-0878
    Keywords: Granular endoplasmic reticulum ; Ultrastructure ; Pinealocyte ; Mole
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    Notes: Summary Ten or more straight tubules, each of which consists of a double unit membrane of granular endoplasmic reticulum with a cylindrical profile, are joined side by side in a raft-like configuration in the cytoplasm of the pinealocytes of Japanese moles. They measure about 60 nm and 100 nm in their inner and outer diameters, respectively, and are often partially connected to unspecialized granular endoplasmic reticulum. Cisterns held between the inner and outer unit membranes with cylindrical profiles vary from 15 nm to 30 nm in width. Ensheathed portions of the cytoplasm are contiguous with cytoplasm outside the tubular units. The inner unit membranes of the tubules bear fewer ribosomal particles than the outer ones.
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  • 62
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    Cell & tissue research 236 (1984), S. 431-438 
    ISSN: 1432-0878
    Keywords: Satellite cells ; Satellite fibres ; Tail muscle ; Urodela ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The incidence and ultrastructure of satellite cells in the tail muscles of urodelan larvae were examined during development during which the number of satellite cells is gradually reduced. They are found more frequently in red than in the white fibres in all four stages examined (stage 53, 64, 66+ and juvenile). As development proceeds, intercellular space between satellite cell and muscle fibre is in general gradually extended and is mostly filled with basal lamina. Small muscle cells, satellite fibres, which are situated under the basal lamina of the parent fibre, are morphologically similar to satellite cells but contain a small amount of myofibrils. Three types of satellite fibres are distinguishable on the basis of differences in K2-EDTA-treated ATPase activity, width of Z line, and parent fibre type. Neuromuscular junctions are visible in satellite fibres.
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  • 63
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    Cell & tissue research 236 (1984), S. 465-470 
    ISSN: 1432-0878
    Keywords: Tendon ; Collagen fibrils ; Morphometry ; Ultrastructure ; Loading ; Mouse
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    Topics: Biology , Medicine
    Notes: Summary This study was designed to gain more detailed morphological information on skeletal tendons in the course of adaptation to physical loading. The effect on collagen fibrils was investigated in 6-week-old mice by means of electron microscopy. Physical loading was performed on a treadmill 5 days a week for 1, 3, 5, 7 and 10 weeks. Morphometric analysis of collagen fibrils revealed the mean diameter, the diameter distribution, the number and the cross-sectional area. The principal observations included: 1. After one week of physical loading an increase in mean fibril diameter (30%, p≦0.01), in number (15%, p≦ 0.05), and in cross-sectional area (15%, p≦0.05), as well as a change in mean fibril diameter distribution. 2. From the third to the seventh week a fall under the level of the controls in mean diameter (26%, p≦0.01), in number (26%, p≦0.01), and a reduced cross-sectional area (17%, p≦0.01), accompanied by signs of splitting of individual collagen fibrils. 3. In the long-term study an increase in fibril number (29%, p≦0.01), a fall in mean diameter from 189 nm in the controls to 179 nm (p≦0.05) but no statistically significant change in the relative cross-sectional area (32%) per unit in comparison to unloaded tendons. The possible physiological implications of the findings are discussed in the light of several regulatory mechanisms known to appear during the course of physical loading in connective tissues.
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  • 64
    ISSN: 1432-0878
    Keywords: Corticotropin-releasing factor ; Immunocytochemistry ; Hypothalamus ; Domestic fowl
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    Topics: Biology , Medicine
    Notes: Summary The corticotropin-releasing factor (CRF)-containing neurons were investigated in the brain of the domestic fowl by means of the peroxidase-antiperoxidase technique at the light-microscopic level. The detection of CRF-immunoreactivity was facilitated by silver intensification. CRF-containing perikarya were found in the paraventricular, preoptic and mammillary nuclei of the hypothalamus and in some extrahypothalamic areas (nuclei dorsomedialis and dorsolateralis thalami, nucleus accumbens septi, lobus parolfactorius, periaqueductal gray of the mesencephalon, nucleus oculomotorius ventralis). Immunoreactive nerve fibers and terminals were demonstrated in the external zone of the median eminence and the organum vasculosum of the lamina terminalis. These results indicate that an immunologically demonstrable CRF-neurosecretory system also exists in the avian central nervous system.
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  • 65
    ISSN: 1432-0878
    Keywords: Steroids ; Vitellogenesis ; Metabolism ; Ultrastructure ; Teleosts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Estradiol injections increase serum level of calcium, amino acid, glucose, protein, ammonia and creatinine in immature Epinephelus akaara, and also increase levels of total lipid, cholesterol, phospholipid and esterified fatty acids. Hepatic protein, glycogen and lipid concentrations also rise after estradiol treatment, and some hepatic enzymes participating in the metabolism of nitrogen, lipid and carbohydrate, show increased activity. Serum vitellogenin levels are increased. Testosterone treatment increases serum protein, total lipid, cholesterol, amino acid and ammonia levels, and also hepatic glycogen content, but in contrast to estradiol treatment, testosterone does not change serum vitellogenin, glucose, calcium, phospholipid, esterified fatty acid and creatinine levels, nor the hepatic lipid and protein content. A small number of hepatic enzymes shows an increased activity. Vitellogenic fish show biochemical changes similar to that of estradiol-treated fish, but are different from those of immature fish. Estradiol treatment induces ultrastructural changes in the hepatocytes of immature fish that are similar to those found in vitellogenic fish. These include a proliferation of rough endoplasmic reticulum and Golgi apparatus, and an increase in glycogen and lipid, all indicative of enhanced metabolic activity.
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  • 66
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    Cell & tissue research 236 (1984), S. 677-683 
    ISSN: 1432-0878
    Keywords: Interneuron ; Synaptology ; Ultrastructure ; Horseradish peroxidase ; Helix pomatia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology, axonal arborization and ultrastructure of synaptic connections of the V21 giant neuron in the visceral ganglion of the snail Helix pomatia has been investigated following intracellular labelling with horseradish peroxidase. The V21 neuron establishes several afferent and efferent axo-axonic connections, mainly along the first half of the primary axon. Collaterals of 200–300 μm length originate from the primary axon, which shows further arborization, and both afferent and efferent synaptic contacts are formed on these fine axon profiles. Afferent and efferent contacts of the cell occur within very short distances of a few micrometers. On the basis of ultrastructure and vesicle and granule content, several afferent terminals can be distinguished on V21 labelled axon profiles. The majority of these afferent terminals resembles peptidergic-(neurosecretory)-like terminals. This finding supports the possible transmitter role of neuropeptides in the central nervous system of gastropods. Our results are consistent with and provide morphological evidence for recent electrophysiological observations suggesting that, in addition to integrating input, the V21 neuron functions as an interneuron in Helix central nervous system.
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  • 67
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    Cell & tissue research 237 (1984), S. 357-362 
    ISSN: 1432-0878
    Keywords: Leydig-Sertoli cell interaction ; FSH stimulation ; Ultrastructure ; Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Interactions between Leydig and Sertoli cells, as well as a stimulatory effect of FSH on Leydig cell activity, have been reported in many studies. In order to investigate these interactions, the ultrastructure of immature pig Leydig cells under different culture conditions has been studied. When cultured alone in a chemically defined medium, there is a marked regression of the Leydig cell smooth endoplasmic reticulum and a swelling of the mitochondria. Addition of FSH or hCG does not prevent these phenomena. Co-culturing of Leydig cells with Sertoli cells from the same animal maintains the smooth endoplasmic reticulum at the level seen in vivo and in freshly isolated Leydig cells. The addition of FSH to the co-culture stimulates its development and increases Leydig cell activity, as assessed by an increase in hCG binding sites and an increased steroidogenic response to hCG. These results suggest that Sertoli cells exert a trophic effect on Leydig cells, and that the stimulatory effect of FSH on Leydig cell function is mediated via the Sertoli cells. These results reinforce the concept of a local regulatory control of Leydig cell steroidogenesis.
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  • 68
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    Keywords: Thyroid ; Immunocytochemistry ; Caldesmon ; Actin ; Endocytosis ; Rat
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary The distribution of caldesmon (a calmodulin-binding, F-actin interacting protein; Sobue et al. 1982) and actin was studied in the rat thyroid gland by means of light-microscopic immunocytochemistry, and the fine-structural distribution of actin filaments was examined by use of heavy meromyosin (HMM). Caldesmon and actin were demonstrated in the apical cytoplasm of almost all the follicle epithelial cells in normal as well as TSH-treated animals. Immunoreactivities for both caldesmon and actin showed almost the same pattern in localization. The smooth muscle cells of the blood vessels were also positive for caldesmon and actin. By electron microscopy, numerous actin filaments decorated by HMM and running perpendicularly or randomly to the apical surface were recognized in the apical cytoplasm of the follicle epithelial cell. These results suggest that caldesmon and actin, in conjugation with calmodulin, play a role in the regulation of cellular activity such as exocytosis and endocytosis in the apical portion of the follicle epithelial cell.
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  • 69
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    Cell & tissue research 238 (1984), S. 221-230 
    ISSN: 1432-0878
    Keywords: Fiber type ; Ultrastructure ; Stereology ; Stimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary When fast-twitch skeletal muscles of the adult rabbit are subjected to continuous low-frequency activity by electrical stimulation of the corresponding motor nerves, the fibers undergo an ultrastructural transformation, so that after 6 weeks they have acquired an appearance typical of slow-twitch fibers. In the present study, stimulation was discontinued at this stage in order to follow the reverse transformation, in which the fibers recovered their original morphological characteristics under conditions of normal endogenous activity. Stereological techniques were used to assess the time course of this process over a period of 20 weeks in terms of fiber cross-sectional area, extent of T-system, thickness of the Z-band, and volume fraction of mitochondria in the fiber core. Fibers of transformed muscles were smaller than those of control muscles, but the differences were no longer evident after 9 weeks of recovery. After 2 weeks the T-system was still of limited extent, as is characteristic of slow-twitch fibers; it increased toward the amount typical of fast-twitch fibers between 2 and 4 weeks, and had reached its full extent by 12 weeks. The wide Z-bands characteristic of slow-twitch fibers were retained for 4 weeks, but the thickness had begun to decrease by 8 weeks and recovery was complete by 12 weeks. The mitochondrial volume did not increase during recovery, in contrast to the large increases which had been observed to take place between 2 and 6 weeks during the fast-to-slow transformation. Overall, the recovery of fast-twitch ultrastructural characteristics was complete, but followed a more extended time course, and involved less myofibrillar disruption at an intermediate stage, than the original fast-to-slow transformation.
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  • 70
    ISSN: 1432-0878
    Keywords: Ultrastructure ; Autoradiography ; Oocytes ; Nucleolus-like bodies ; Teleost
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary Cytoplasmic granulo-fibrillar masses, usually termed nucleolus-like bodies (NLB) or nuages, have been described in several different cell types. They are sometimes associated with a mitochondrial arrangement, this association often being marked during certain phases of the oocyte cycle. In Xiphophorus helleri, NLB consist of fibrillar and granular material that gradually becomes more granular during meiotic prophase I, and is associated with mitochondrial arrangements during diplotene and dictyate of meiosis. Autoradiographic studies of uridine incorporation into the nucleolus and subsequently into NLB suggest that the latter represent a reserve of ribonucleoproteins that is later used in ribosomal maturation during vitellogenesis.
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  • 71
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    Cell & tissue research 238 (1984), S. 271-288 
    ISSN: 1432-0878
    Keywords: Compound eye ; Ultrastructure ; Grass shrimp, Palaemonetes pugio ; Light adaptation ; Dark adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cone cells and corneagenous cells possess extensive networks of smooth tubular endoplasmic reticulum that may be involved in optical reflectance and light-adaptational responses, respectively. The extracellular basal lamina of the basement membrane is confluent with glial cell capillary walls and may prove to be a viaduct for the transmission of hemolymph-borne substances to the retina or of retinal degradation products to the hemolymph. In addition to dense pigment granules, the distal pigment cells are shown for the first time to contain migratory reflecting platelets that are usually polymorphic in light-adapted eyes but are rectangular in dark-adapted eyes. In the latter these plates become aligned against the crystalline cones and presumably contribute to the reflection superposition optics of the grass shrimp. Dark-adapted retinular cells possess well-developed perirhabdomal cisternae, oblong or ovoid mitochondria, generally vesicular rough endoplasmic reticulum, and occasional, spherical, calcium-like intrarhabdomal inclusions. Light-adapted retinular cells possess poorly developed perirhabdomal cisternae, lamelliform rough endoplasmic reticulum, and condensed mitochondria frequently associated with lipid droplets and pigment granules. The cytoplasmic boundaries of the reflecting pigment cells expand into the extracellular spaces between individual ommatidial retinular cells during dark adaptation and recede to the interommatidial extracellular spaces during light adaptation. Cytoplasmic microfilament bundles found only at the bases of partially light-adapted rhabdomeric microvilli may be involved in microvillar shortening.
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  • 72
    ISSN: 1432-0878
    Keywords: Urotensin ; Caudal neurosecretory system ; Immunocytochemistry
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    Notes: Summary The localization of urotensin I has been investigated in the caudal neurosecretory system of the white sucker (Catostomus commersoni). The peptide is present in all the cells of the system both large and small, in the large axons passing to the urophysis, and in fine beaded fibres not only within the urophysis but also in a fine plexus lateral to the large cells in the spinal cord proper. The possibility that the caudal neurosecretory system is not a functionally uniform system but rather a collection of dissimilar cells of different synaptic inputs with a common entity, urotensin I, is discussed. Moreover, the feasibility of a urotensin I feedback loop is described.
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  • 73
    ISSN: 1432-0878
    Keywords: Pituitary rat ; LH cells ; FSH cells ; ACTH cells ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary By means of immunocytochemistry, the development of ACTH-, LH- and FSH cells was examined in the anterior pituitary of 5-day-old neonatal, 15-day-old immature and adult rats. ACTH-positive cells are angular and the periphery of these cells is strongly reactive with anti-ACTH serum. In contrast, LH- and FSH-immunopositive cells are ovoid elements, ranging in cell size and intensity of staining. Angular cells, in which only the cell periphery reacted with anti-LHβ serum, were observed in neonatal and immature rats; however, these cells were not stained with either anti-FSHβ serum or anti-ACTH serum. Observation of serial semithin sections revealed that ACTH-immunopositive cells do not react with either anti-LHβ or anti-FSHβ serum. Finally, it was observed that ACTH cells and LH cells are both functionally differentiated already in 5-day-old neonatal rats.
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  • 74
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    Cell & tissue research 235 (1984), S. 77-83 
    ISSN: 1432-0878
    Keywords: Pituitary (rat) ; LH cells ; FSH cells ; Rapid freeze-substitution ; Immunocytochemistry ; Ferritin antibody
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rapid freeze-substitution fixation was employed in immunocytochemical studies on the localization of LH and FSH in the typical gonadotrophs of the anterior pituitary in the untreated male rat; a modification of a recently described ferritin antibody method (Inoue et al. 1982) was used in these studies. It was shown that rapid freeze-substitution fixation provides good preservation not only of the ultrastructure but also of the antigenicity. Both LH and FSH were clearly demonstrated in the same gonadotrophic cells, but the subcellular localization of these gonadotrophins differed: (i) LH was mainly located in small secretory granules, 250–300 nm in diameter; (ii) FSH was mainly present in large secretory granules, up to 500 nm in diameter. In the pituitary gland of the adult male rat, all gonadotrophs that react to antibodies against gonadotrophins are characterized by small and large secretory granules. Other types of cells of the anterior pituitary containing either small secretory granules or resembling corticotrophs with secretory granules assembled at cell periphery did not react to either anti-LH beta or anti-FSH beta serum. For light microscopy, the peroxidase antibody method was used. All of the gonadotrophin-positive cells contain both LH and FSH. None of the pituitary cells reacted to antibody against only one gonadotrophin. However, some cells are “LH-rich” while other cells are “FSH-rich”.
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  • 75
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    Cell & tissue research 235 (1984), S. 159-169 
    ISSN: 1432-0878
    Keywords: Anterior pituitary ; Gonadotropic cells ; Immunocytochemistry ; Testosterone binding ; Cryo-ultramicrotomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Several attempts have been made to localize steroids by means of immunocytological techniques. However, these methods were found inadequate for detecting steroids bound to their receptors. To localize endogenous testosterone (T) in its target cells at the ultrastructural level, an immunocytological technique was performed on ultrathin sections obtained by cryo-ultramicrotomy. T was detected in the pituitary glands obtained from intact male or female rats and castrated rats, but not in castrated + adrenalectomized rats. Animals were also injected either with testosterone, with other steroids (estradiol, progesterone, corticosterone) or with an androgen antagonist (cyproterone acetate). In addition, some ultrathin sections were preincubated either with phosphate buffers of various pH, corticosterone, cyproterone acetate solution, or with T solution. The content of T in the pituitary before and after fixation was measured by radioimmunoassay; it decreased after fixation. T immunoreactivity was localized in the gonadotropic cells only, both in the male and female rats. At the subcellular level, the immunoreactivity was detected in the cytoplasmic matrix and in the nucleus. Immunoreactive T disappeared 1) in rats after castration+adrenalectomy; by means of radioimmunoassay no T was measured in these pituitary glands; 2) in rats injected with 25 (μg/rat of cyproterone acetate; 3) after preincubation of pituitary sections on a drop of cyproterone acetate (1 × 10-6 M). The immunocytological reaction was not modified when the rats were injected with estradiol, progesterone or corticosterone (1 mg/rat), or after preincubation of the sections with corticosterone (1 × 10-3 M), or a buffer solution at pH 7.6. Lower or higher pH values led to a strong decrease in the immunoreactivity. After injection of T (15 μg/rat) the immunocytological reaction was more abundant in the nucleus and less in the cytoplasm. The immunoreactivity was again observed when the sections were preincubated with cyproterone acetate solution and then with T solution. These data suggest that T can be detected by means of immunocytochemistry. It is probably bound to a specific binding site.
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  • 76
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Supraoptic nucleus (SON) ; Oxytocin neurones ; Neuronal appositions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pre-embedding immunocytochemistry was performed on vibratome sections of the hypothalamus of lactating rats using antiserum directed against oxytocin. Electron microscopy revealed that numerous immunopositive somata and dendrites in the supraoptic nucleus were in direct apposition, without glial interposition; a number of them were also bridged by “double” synapses. The observations support the contention that the ultrastructural reorganisation of the nucleus apparent at lactation affects the magnocellular neurones secreting oxytocin.
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  • 77
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    Cell & tissue research 235 (1984), S. 295-301 
    ISSN: 1432-0878
    Keywords: Tfm/Y mouse ; Submandibular gland ; Sexual ; dimorphism ; Androgens ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the submandibular gland of the mouse with testicular feminization (Tfm/Y) was studied by light and electron microscopy. The architecture of the Tfm/Y gland proved to be rather similar to that of the normal female mouse in both tubular ratio and structure. Granular convoluted tubular cells in Tfm/Y mice characteristically had fewer secretory granules and increased cytoplasmic vacuoles than normal littermates, suggesting an altered synthesis of secretory granules in this cell type of the Tfm/Y mouse. Moreover, there were differences in the ultrastructure of submandibular glands between Tfm/Y and normal female mice. In the gland of the Tfm/Y mouse, basal striations of the striated secretory tubular cells were not so developed and granular intercalated duct cells were less than those of normal females. These findings support the evidence that the secretory tubule of the mouse submandibular gland responds to androgens, resulting in accentuated development in the male, while also suggesting the possibility that the mouse submandibular gland is regulated by other factors which lead to the prominent sexual dimorphism observed in this gland.
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    Cell & tissue research 235 (1984), S. 427-432 
    ISSN: 1432-0878
    Keywords: DPP IV ; Salivary glands ; Ultrastructural localization ; Immunocytochemistry ; PAP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural localization of dipeptidyl peptidase IV (DPP IV) (EC 3.4.14.5) in rat submandibular and parotid glands was studied immunocytochemically by the peroxidase-antiperoxidase (PAP) method, using a monospecific antiserum against rat kidney DPP IV. There were no differences in the immunocytochemical localization of DPP IV between submandibular and parotid glands. In these glands, DPP IV was primarily found to be associated with the luminal and intercellular canalicular plasma membranes of acinar cells and with the luminal plasma membranes of intercalated and striated duct cells. Occasionally, immunoreaction of DPP IV was detected in cytoplasmic vesicles (vacuoles), lysosomes, and multivesicular bodies in some acinar cells as well as in ductal epithelial cells. Furthermore, the reaction product was also found within the lumina of peri-acinar and peri-ductal capillaries and in the cytoplasm of some fibroblasts in the interstitial connective tissue. These data suggest that DPP IV in the submandibular and parotid glands may play some role in the secretion or reabsorption processes of secretory proteins and peptides in these glands.
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  • 79
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    Cell & tissue research 235 (1984), S. 463-466 
    ISSN: 1432-0878
    Keywords: Endocytosis ; Kidney (rat) ; Proximal tubule ; Apical vacuoles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Following perfusion fixation of the rat kidney with glutaraldehyde the proximal tubule cells display small apical vacuoles, large apical vacuoles, and apical vacuoles in which a part of the limiting membrane is invaginated into the vacuole. These invaginated apical vacuoles occur more frequently in proximal convoluted tubules than in proximal straight tubules. One tubular cell may contain apical vacuoles of different sizes and stages of invagination, ranging from larger vacuoles with a wide lumen and a small area of invaginated membrane to smaller elements with no apparent lumen and a large area of invaginated membrane. Invaginated apical vacuoles lie either singly in the cytoplasm or close to the membranes of other apical vacuoles, but never in contact with the cell membrane or the membranes of lysosomes, endoplasmic reticulum, Golgi apparatus, mitochondria and peroxisomes. These findings suggest that the invaginated apical vacuoles are not fixation artifacts, but rather develop in living state in cells of the proximal tubule from spherical endocytotic elements.
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  • 80
    ISSN: 1432-0878
    Keywords: S-100 protein ; Thymus ; Interdigitating cells ; Immunocytochemistry ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present study deals with the localization and ultrastructure of S-100-immunoreactive cells in the human thymus. These immunoreactive cells are distributed mainly in the medulla with some scattered elements in the cortex. Electron-microscopic observation revealed that the cells are characterized by an irregularly shaped nucleus, tubulovesicular structures in the cytoplasm and characteristic interdigitations of the plasma membrane. The cells often embrace lymphocytes with their branched processes. On the basis of these morphological features, the immunostained elements were identified as interdigitating cells (IDCs). The immunocytochemistry for S-100 visualizes the precise distribution and extension of the IDCs under the light microscope and indicates that the IDCs form no structural networks such as those established by the thymic epithelial cells. Since the IDCs in human lymph nodes have also been reported to contain S-100-like immunoreactivity, S-100 protein can be regarded as a useful marker for identifying the IDCs in the human thymus and other lymphoid organs.
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  • 81
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    Keywords: Immunocytochemistry ; FMRF-amide ; Neurotransmitter ; Palaemon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By use of a specific antiserum against the molluscan cardio-excitatory tetrapeptide FMRF-amide in combination with the PAP-method it was possible to obtain positive immunocytochemical reactions in several neurosecretory regions of the eyestalk of the prawn Palaemon serratus. FMRF-amide-like material was found in perikarya and nerve fibers of the medulla terminalis and in neurons in the lamina ganglionaris. The immunoreactivity observed in the glandular tissue located at the basal insertion of the eyestalk muscles must be ascribed to a non-specific reaction. The identification of immunopositive nerve fibers, ending on a nerve bundle in the medulla terminalis, and the fact that immunoreactive material was absent in the neurohemal sinus gland seem to indicate a neurotransmitter/neuromodulator function.
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  • 82
    ISSN: 1432-0878
    Keywords: Fetal porcine pituitary ; ACTH, MSH, β-LPH, α- and β-endorphin, GH, PRL ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The aim of the present study on the fetal porcine pituitary was (1) to detect by means of the immunoperoxidase technique the earliest stages of cells producing polypeptide hormones: β-MSH, ACTH, β-LPH, α- and β-endorphin, growth hormone (GH) and prolactin (PRL), (2) to study the development of the synthesis and the storage of these hormones during fetal life, and (3) to detect whether several hormones can be located in one and the same cell. The corticotropic cells were revealed as the earliest functional elements of the fetal anterior pituitary. Our results indicate clearly that ACTH, β-MSH, β-LPH, α- and β-endorphin appear at 34 days in the same regular, round or ovoid cells; no differences in the time of their appearance could be observed. The ACTH-cells, irregular or angular in shape and endowed with cytoplasmic processes such as described in the adult pituitary, were not seen until day 50. The first GH-cells were detected between 40 to 45 days of fetal life. From day 45 to 90, the GH-cells greatly increased in number and in staining intensity of their progressively extending cytoplasmic area, but they displayed the same regular and round shape. The PRL-cells were the last cell type to appear in the fetal pituitary. The first PRL-cells, small in size and round or ovoid in shape with a high nucleus/cytoplasm ratio, were detected at day 70. At day 80, the PRL-cells increased in size and staining intensity. They displayed an irregular elongated or stellated shape and cytoplasmic processes resembling those characteristic of the adult pituitary. These data suggest that in the fetal porcine pituitary: (1) ACTH, β-LPH and related peptides are synthesized and stored in the same cells, and (2) PRL and GH appear in individual cellular elements.
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  • 83
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    Cell & tissue research 236 (1984), S. 339-343 
    ISSN: 1432-0878
    Keywords: Moulting ; Mechanosensory hair ; Chordotonal organ ; Ultrastructure ; Crustacea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of hair mechanoreceptors in crayfish during moulting was investigated with special attention to the interface apparatus between cuticular hairs and sensory cells: the chorda. The chordae are lost with old exuviae at every moulting. They are drawn out from a moulting canal at the tip of the new hair. The chordae are regenerated from a material secreted by sheath cells after moulting. Therefore, the chorda is an inward projection of the cuticular exoskeleton, and it has direct contact with the sensory element, the scolopidium. The scolopidium has been found in both hair mechanoreceptors and subcuticular chordotonal organs in crustaceans, and is thought to be a primitive type of mechano-sensory transducing element. The present observation gives additional evidence for the homology of two sensory elements in arthropods, i.e., the cuticular hair sensilla and subcuticular chordotonal organs.
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  • 84
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    Cell & tissue research 236 (1984), S. 87-97 
    ISSN: 1432-0878
    Keywords: Iodination ; Membrane shedding ; Peroxidase ; Thyroid follicle cell ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Clusters of luminal dense bodies, limited by a triple-layered membrane, were found in all follicle lumina in thyroid glands of mice. After thyroxine treatment the number of luminal dense bodies increased, especially in the periphery of the lumen, where the intraluminal bodies often displayed a striking resemblance to microvilli. In hyperplastic goiters, obtained by feeding mice with propylthiouracil, luminal dense bodies were replaced by intraluminal vesicles. During goiter involution the vesicles were gradually replaced by luminal dense bodies; the presence of intermediate forms suggests that vesicles and dense bodies are basically the same formations. Luminal dense bodies were observed in colloid droplets indicating their removal by endocytosis. As demonstrated by electron-microscopic cytochemistry, luminal dense bodies contain a membranebound peroxidase, and electron-microscopic autoradiography after administration of 125I indicate that they possess an iodinating capacity. Our observations on mouse thyroid glands suggest that the luminal dense bodies, which appear as vesicles in hyperplastic glands, are formed by shedding of the apical plasma membrane of the follicle cell. The shedding process might be of importance for the turnover of plasma-membrane material.
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  • 85
    ISSN: 1432-0878
    Keywords: Anterior pituitary, porcine ; Gonadotropic hormones (FSH, LH) ; Immunocytochemistry ; Cellular compartments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pre- and post-embedding immunocytochemical methods based on the use of specific antibodies against β-subunits of porcine LH and FSH were applied to determine the changes occurring in the anterior pituitary of the pig after gonadectomy. The results showed that (1) the total number of immunoreactive gonadotropes increased from 21–25% in control animals to 24–37% in castrated animals; (2) all gonadotropes contained both LH and FSH; (3) several types of immunoreactive LH/FSH cells were revealed; and (4) the two immunocytochemical methods used with dispersed cells localized the hormones in the same subcellular sites. However, the staining intensity in the different locations varied depending on the method applied. With the post-embedding method, a dense reaction product was found in the secretory granules but the cisternae of RER and the Golgi saccules were always slightly reactive. After the pre-embedding method, the staining intensity in the RER-cisternae and in the Golgi saccules was greatly increased. Thus, the two methodological approaches used in this study have permitted to visualize immunocytochemically the gonadotropic hormones not only at the sites of their storage but also along the intracellular pathway of the secretory material, i.e., at the site of its synthesis and during its passage via the Golgi zone.
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  • 86
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    Cell & tissue research 236 (1984), S. 171-180 
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Ultrastructure ; Supraoptic nucleus ; Neuropil ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The neuropil located ventral to the SON was investigated by the use of immunoperoxidase staining for neurophysins, oxytocin and vasopressin, and electron miroscopy. The study was performed in six groups of rats: 1) control; 2) infusion of isotonic saline into the CSF; 3) infusion of hypertonic saline into the CSF; 4) drinking hypertonic saline for 4 days; 5) same as group 4 but injection of colchicine into the CSF on second day of dehydration; 6) salt loading for 3 months. In the control rats the ventral neuropil contained a few immunoreactive processes, the general morphology of which was completely different from that of the neurosecretory axons emerging from the SON at its dorsal aspect. In rats of groups 3 to 6 the ventral processes (VP) became loaded with neurosecretory granules, whereas the perikarya and axons were depleted. Based on their general morphology and reactivity pattern it is suggested that the VP are dendrites. Most of these “dendrites” were embedded in a glial cushion formed by the processes of a particular type of marginal glia. Some of these “dendrites” enveloped an arteriole penetrating the optic tract. All VP were rich in synaptic contacts. The possibility that the VP of neurosecretory cells may be functionally related to the subarachnoid CSF and the arteriolar blood flow is discussed.
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  • 87
    ISSN: 1432-0878
    Keywords: Peripolar cells ; Juxtaglomerular apparatus ; Newborn sheep ; Dexamethasone ; Ultrastructure ; Cytoplasmic granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the renal juxtaglomerular region of newborn sheep, it was found that glomerular peripolar cells and their granules were very much larger than those found in fetal lambs or adult sheep. Similar peripolar cell hypertrophy was triggered in fetal lambs treated in utero with intraperitoneal injections of dexamethasone. Ultrastructurally, granules of peripolar cells from newborn lambs resembled closely the enlarged zymogen granules described in the pancreas of newborn rats. Such peripolar cell hypertrophy may reflect a functional adaptation of the kidney to immediate postnatal life.
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  • 88
    ISSN: 1432-0878
    Keywords: Development ; Enterocytes ; Fish ; Mitosis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The processes of proliferation, cell division and differentiation of intestinal epithelial cells have been studied during development of the fish, Barbus conchonius. On the 3rd day, nearly all cells of the presumptive gut proliferate. Once the intestinal epithelium begins to differentiate, a decreasing percentage of proliferative cells can be found. On the 7th day, when intestinal folds start to develop, the proliferative cells become restricted to the future basal parts of the folds. Ultrastructural examination of 3H-thymidine-labeled cells and mitotic cells of 6-day-old larvae shows that functional enterocytes are proliferative. The same feature is suggested for older fish. Proliferating undifferentiated “dark” cells, characterized by many free ribosomes and a few organelles, are also present in the intestinal epithelium of larval fish; they are considered to be stem cells, mainly for goblet cells. Proliferating goblet cells and enteroendocrine cells were not observed. The latter cell type is scarce and has a long turnover time. A common feature of all these dividing cells is the presence of isolated spherical to cylindrical lamellar structures which may have lost contact with the cell membrane during prophase; they probably regain this contact by fusion with the cell membrane at the end of mitosis.
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  • 89
    ISSN: 1432-0878
    Keywords: ACTH cells ; Immunocytochemistry ; Morphometry ; Spontaneous hypertension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary ACTH-immunoreactive cells in the anterior pituitary of 4-week-old spontaneously hypertensive rats (SHR) were studied with immunocytochemical and morphometric techniques. The results were compared with data from age-matched normotensive Wistar-Kyoto rats (WKY). No significant differences were found in volume density and average size of ACTH-immunoreactive cells between these two strains. However, SHR showed a significantly larger anterior lobe (2 P 〈 0.01) than WKY, indicating that the total number of ACTH-immunoreactive cells in the anterior pituitary is greater in SHR than in WKY. These data are in agreement with radioimmunological determinations showing a significantly elevated content (2 P 〈 0.01) but only a moderately higher concentration (0.05 〈 2 P 〈 0.10) of ACTH in the anterior pituitary of SHR as compared to WKY. The present results suggest an enhanced availability of ACTH in the anterior pituitary of 4-week-old SHR, a fact which could explain the markedly enhanced stress-induced release of ACTH previously found in these animals. This study further supports the hypothesis that, among other factors, an instability of the hypothalamo-pituitary-adrenal axis may contribute to the development of genetically programmed hypertension.
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  • 90
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    Cell & tissue research 236 (1984), S. 517-525 
    ISSN: 1432-0878
    Keywords: Bone marrow ; Actin ; Cell motility ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Blood cells proliferate extravascularly in the bone marrow and enter the circulation by migrating through endothelial cells of venous blood sinuses. This migration, or diapedesis, was suspected to involve actin. To test for the presence and distribution of actin, sections of rat bone marrow were examined by indirect immunocytochemistry. Affinity purified rabbit antichicken gizzard actin antibody, and goat-antirabbit IgG-FITC, or goat antirabbit IgG colloidal gold probes were used. The migrating cell contacts the endothelial cell and forms a podosome (a cortical bleb). Immunocytochemistry shows this region to contain actin. As diapedesis proceeds the podosome deforms, then breaches the endothelial cell. At this time the anterior portion of the leukocyte shows heavy labeling for actin. When the migratory cell traverses approximately half of its length through the endothelial cell, actin appears prominent in the caudal region of the cell. The immunocytochemical data suggest that actin is nonrandomly distributed in leukocytes undergoing diapedesis and may be a component of the force-generating mechanism responsible for this transcellular migratory event.
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  • 91
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    Cell & tissue research 237 (1984), S. 123-129 
    ISSN: 1432-0878
    Keywords: Pancreas, exocrine (rat) ; Ultrastructure ; Morphometry ; Development, ontogenetic ; Zymogen granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pancreatic acinar cells of rats obtained at 1,2, 3, 5, 7 and 14 days of age were examined using fine structural and morphometric techniques. From 5 days of age onwards, the acinar cells were analysed twice per day, at 20.00 h and 08.00 h. The present study demonstrates changes in the average volume of the cell, nucleus and cytoplasm, and volume densities of various cytoplasmic organelles during the first two weeks after birth. During early postnatal life, the volume density of rER increases, whereas that of zymogen granules decreases. From 5 days of age onwards, the volume densities of these two organelles differ significantly at 20.00 h and 08.00 h. During the first 2–3 days after birth, inclusion body-like structures appear in the cytoplasm of acinar cells; they contain aggregated zymogen granules and, sometimes, amorphous structures or cytoplasmic organelles. These structures also occur in interstitial cells and cells located in the intercalated region between acinar and ductal epithelial cells. Serum level of α-amylase activity is high at birth, compared with other stages during the first three weeks. Degenerating acinar cells and cell debris can be seen in the acinar and ductal lumina during these stages, a feature suggesting holocrine secretion. Cellular polarity appears to be incomplete during the first two or three days after birth.
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  • 92
    ISSN: 1432-0878
    Keywords: Pituitary gland ; Goat ; Folliculo-stellate cell ; GH cell ; S-100 protein ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Goat pituitary glands were immunohistochemically studied with antisera for bovine S-100 protein, rat LHβ, FSH, TSHβ, prolactin, ovine GH, and porcine ACTH1–39 by use of the superimposition technique on adjacent sections. Folliculo-stellate (F-S) cells were divided into two categories on the basis of ultrastructural properties: One consisted of a mass of agranular cells in which the pseudolumina were equipped with microvilli and cilia. Elongate gap junctions were often observed among these cells. The other was a group of granulated cells with or without pseudolumina. In this group the gap junctions were shown to be disintegrated. The dense granules 150–250 nm in diameter began to accumulate in the cells. However, neither type of these F-S cells was immunostained for S-100 protein. On the other hand, numerous polygonal, elongate, irregular or stellate cells containing S-100 protein were distributed throughout the gland. Most of them were immunohistochemically identical with the GH cells laden with the secretory granules 250–450 nm in diameter, but some of them were identical to TSH and prolactin cells which immunostained faintly for S-100 protein. This appears to be the first demonstration of GH cells intensely immunostained for S-100 protein.
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  • 93
    ISSN: 1432-0878
    Keywords: Hagfish ; Brain ; Pituitary ; FMRF-amide ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Paraffin sections of brain and pituitary of the hagfish Eptatretus burgeri were immunostained with an antiserum to FMRF-amide. Immunoreactivity was visible in a large number of neurons in the posterior part of the ventromedial hypothalamus and in long neuronal processes extending cranially from the hypothalamus to the olfactory system and caudally to the medulla oblongata. FMRF-amide-like immunoreactivity was also found in cells of the adenohypophysis. These observations suggest that the hagfish possesses a brain FMRF-amide-like transmitter system and pituitary cells containing FMRF-amide-like material. Antisera to ACTH, α-MSH and pancreatic polypeptide gave no immunoreaction in hagfish brain or pituitary.
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  • 94
    ISSN: 1432-0878
    Keywords: Crustacean hyperglycemic hormone ; Astacus leptodactylus ; Immunocytochemistry ; Quantitative electron microscopy ; Secretory cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunocytochemical staining demonstrates striking differences in staining intensity among individual crustacean hyperglycemic hormone (CHH)-producing cells in the eyestalk of the crayfish Astacus leptodactylus. Based on these differences we arbitrarily subdivided the CHH-cells into three categories representing increasing immunoreactivity respectively: + cells, + + cells, and + + + cells. Electron microscopic investigations reveal that these differences in immunostaining are correlated with differences in the numerical density of the neurosecretory granules in the cytoplasm and that these may reflect differences in activity among the CHH-cells. Morphometric analyses at the light- and electron-microscopic levels indicate that the three distinguished categories of immunopositive cells represent different stages in the CHH-synthesizing process of the cells. The results of the present study demonstrate the application of the PAP-technique at the light-microscopic level as a method to obtain information pertaining to the dynamics of secretory activity of the CHH-cells.
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  • 95
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    Cell & tissue research 237 (1984), S. 321-327 
    ISSN: 1432-0878
    Keywords: Neuropeptide Y ; Immunocytochemistry ; Respiratory tract ; Ear, middle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Nerve fibres displaying neuropeptide-Y (NPY) immunoreactivity are abundantly distributed in the respiratory tract of cats, guinea-pigs, rats and mice. Fine beaded NPY fibres were seen in whole-mount spreads of the middle-ear mucosa. In the nasal mucosa and in the wall of the Eustachian tube NPY fibres were numerous around arteries and arterioles but sparse in the vicinity of veins; single fibres were found close to the acini of seromucous glands. In the tracheobronchial wall NPY fibres occurred in the proximity of blood vessels, in the subepithelial layer and in the smooth muscle. Surgical and chemical (6-hydroxydopamine treatment) sympathectomy resulted in disappearance of adrenergic and NPY-containing nerve fibres in the nasal mucosa. Sequential staining with antibodies against dopamine-β-hydroxylase (DBH) and NPY revealed that DBH and NPY occur in the same perivascular nerve fibres in the nasal mucosa. The distribution of NPY fibres in the respiratory tract suggests multiple functions of NPY, such as regulation of local blood flow, glandular secretion and smooth muscle activity.
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  • 96
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    Cell & tissue research 238 (1984), S. 1-12 
    ISSN: 1432-0878
    Keywords: Lung ; Amphibia ; Ultrastructure ; Smooth muscle ; Extracellular matrix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The lung of the giant salamander, Amphiuma tridactylum, is divided into respiratory alveoli by muscular septa that increase the surface area of the lung as well as provide a mechanism for its almost complete collapse during exhalation. The epithelium of the internal surface is of two types: respiratory, composed of a single layer of pneumocytes overlying anastomosing capillaries, and non-respiratory, composed of ciliated cells and mucus-secreting goblet cells. Non-respiratory epithelium covers the apical edges of the septa, whereas the respiratory epithelium lines the alveoli. The smooth muscle of the septa and walls of the lung was studied in preparations of uninflated and acetylcholine-contracted lung. The muscle cells are ultrastructurally similar to other types of smooth muscle but are surrounded by extraordinary amounts of extracellular matrix, containing collagen and elastic fibers and numerous fine fibrils of unknown composition. Smooth muscle in isolated lung strips contracted in a dose-dependent manner when treated with acetylcholine or methacholine; contraction was blocked by atropine. Responses of lung strips to adrenergic agents were limited; only high doses of adrenalin caused slight relaxation of previously contracted muscle. These observations support the hypothesis that contraction of pulmonary smooth muscle is responsible for the ventilatory efficiency of the lung.
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  • 97
    ISSN: 1432-0878
    Keywords: Subcommissural organ ; Secretory granules ; Secretory process ; Ultrastructure ; Natrix maura (Reptilia, Ophidia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Two different types of ependymal cells were found in the subcommissural organ (SCO) of Natrix maura. Most secretory cells showed morphological features resembling the general structure and ultrastructure of cells in the SCO of other vertebrates. This report describes a second population of cells lining a portion of the dorsal groove of the SCO. These cells were not selectively stained by chromalum-hematoxylin and, under the electron microscope, they were characterized by scarce surface differentiations, sparse apical cytoplasm and short basal processes. Flat, parallel cisternae of the rough endoplasmic reticulum produced vesicles that appeared to be transported to the well-developed Golgi apparatus. Dense secretory granules about 200 nm in diameter were found in the Golgi region. Similar granules were seen in the vicinity of the apical plasma membrane; some of them opened toward the ventricle. All these characteristics clearly differentiate this cell group from the other secretory cells lining the SCO laterally and ventrally.
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  • 98
    ISSN: 1432-0878
    Keywords: Teeth (Macropodinae) ; Enamel (opaque, translucent) ; Ultrastructure ; Enamel hardness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Teeth of three macropod species, M. giganteus, W. bicolor and P. concinna, have been studied using the techniques of light microscopy, scanning- and transmission-electron microscopy and hardness measurement. Light microscope observations showed that the teeth of these species had a translucent enamel region close to the dentine and an outer opaque enamel region at the tooth's surface. These regions were not related to the presence or absence of tubules which are a characteristic feature of marsupial enamel. Hardness tests showed that the opaque enamel was softer than the translucent enamel. Scanning electron microscope observations revealed that there was no correlation between any particular prism packing or orientation and the opaque and translucent enamel regions. Transmission electron microscope observations showed that the translucent enamel region consisted of well defined prisms and well packed, lath-like crystals, whereas the opaque enamel was disrupted by voids (which ranged in size from enlarged micropores to about 2 μm in diameter in extreme cases) between crystals and some randomly oriented, loosely packed crystals. This disruption within the opaque enamel region was more common at prism boundaries but pockets of disrupted enamel were also found within prisms and interprismatic regions. The opacity of the enamel was caused by scattering of light from the voids. The ultrastructure of the opaque enamel region indicated that this region was hypomineralized; hardness tests and polarized light microscope observations were consistent with these results.
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  • 99
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Biogenic amines ; Vasotocin ; Lymnaea stagnalis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Consecutive sections of certain neurons in the central ganglia of the pond snail Lymnaea stagnalis appear to be immunoreactive to anti-dopamine and anti-serotonin. The Cerebral Giant Neurons stain in addition with antivasotocin. The observations indicate the presence of two biogenic amines within the same neuron and in addition their co-existence with a biologically active peptide.
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  • 100
    ISSN: 1432-0878
    Keywords: Retinal photoreceptors ; Opsin ; Optic nerve ; Immunocytochemistry ; Cyclostome, Myxine glutinosa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Opsin-immunoreactive sites in the eye and optic nerve of the hagfish, Myxine glutinosa, were studied by use of light-microscopic pre- and postembedding peroxidase-antiperoxidase or avidin-biotin-peroxidase techniques, and the immuno-electron-microscopic protein A-gold method. At the light-microscopic level, a strong opsin immuno-reaction was obtained on the outer segments of the photoreceptor cells with sheep and rat antibodies against bovine (rhod)opsin. These outer segments were located in the marginal photoreceptor space and in follicles of the retina, as well as in the tubular lumen of the optic nerve. Ultrastructurally, two classes of outer segments can be distinguished; most of them exhibited a strong antiopsin reaction, while certain elements lacked immunoreactivity with the antisera employed. The protein A-gold particles marked opsin-immunoreactive sites on the photoreceptor membranes. The presence of opsin-immunoreactive material in the retina and optic nerve of the hagfish strengthens the view that this primitive eye lacking a cornea, lens and vitreous body is engaged in light perception. The morphological similarity between the eye and pineal tissue is discussed in connection with the absence of a pineal organ in this species.
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