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  • Cell & Developmental Biology  (2)
  • Heart rate  (2)
  • Life and Medical Sciences  (2)
  • 1
    Electronic Resource
    Electronic Resource
    A Golgi study of the opossum ventral basal complex (1983)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 177 (1983), S. 277-299 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphology of neurons in the ventral basal complex (VBC) of the adult opossum (Didelphis virginiana) is described from thick coronal brain sections, using Golgi-, horseradish peroxidase (HRP)-, and Nissl-staining methods. Soma cross-sectional area, dendritic field shape, and the number of appendages (spines) in a defined major branch zone (MBZ) are quantified and statistically analyzed. Results indicate that neurons in opossum VBC have relatively large cell bodies, dendrites which branch in a tufted pattern, and numerous dendritic appendages. These neurons are designated as relay cells because of (1) their tufted dendritic branch patterns, considered characteristic of thalamic relay cells (Ramon-Moliner, '62), and (2) the similarity of their soma sizes with HRP-labeled somata after somatosensory cortical injections. Neurons with traditionally described interneuron morphology do not appear to be present in the VBC of this animal, and, in this respect, the neuronal morphology of opossum VBC is similar to that in rat (McAllister and Wells, '81).Based on statistical analysis of the structural features observed, the presumed relay cells in opossum VBC do not show significant differences in morphology, and consequently are not subdivided into classes. Opossum VBC neurons are recognized as forming a single category in which broad and continuous variations in morphology are indicated. Recognition of a singular class of relay cell is consistent with descriptions for rat and cat VBC (Scheibel and Scheibel, '66), but at variance with a previous report for the primate Galago VBC (Pearson and Haines, '80) subdividing thalamic relay cells into Types I, II, and intermediate categories.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051770306
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Ontogeny of heart rate in embryonic and nestling crows (Corvus corone and Corvus macrorhynchos) (1999)
    Springer
    Journal of comparative physiology 169 (1999), S. 256-262 
    Details
    ISSN: 1432-136X
    Keywords: Key wordsCorvus corone ; Corvus macrorhynchos ; Embryo ; Chick ; Heart rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The developmental patterns of mean heart rate (MHR) and instantaneous heart rate (IHR) were investigated in embryos and chicks of altricial Corvuscorone and Corvus macrorhynchos. The MHR of embryos increased linearly with time from 250 beats · min−1 at mid-incubation to 290 beats · min−1 in hatchlings. MHR during the pipping period was maximal, but only marginally higher than in hatchlings. MHR was stable at about 290–300 beats · min−1 during the 1st week after hatching. Spontaneous heart rate (HR) decelerations and accelerations were found in embryos and chicks, disturbing the baseline HR with increasing frequency during development. However, the IHR accelerations developed later and were less frequent than in precocial species. IHR and body temperature decreased during mild cold exposure (23–25 °C) and IHR accelerations were reduced in nestlings during the 1st week. We suggest that the development of parasympathetic control of HR in crows occurs at 60% of incubation, similar to precocial embryos, but sympathetic control may be delayed and suppressed in contrast to precocial embryos.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003600050219
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  • 3
    Electronic Resource
    Electronic Resource
    Development and regulation of heart rate in embryos and hatchlings of gulls (Larus schistisagus and Larus crassirostris) in relation to growth (2000)
    Springer
    Journal of comparative physiology 170 (2000), S. 429-438 
    Details
    ISSN: 1432-136X
    Keywords: Key words Avian ; Larus ; Growth ; Heart rate ; O2 pulse ; AbbreviationsACG acoustocardiogram ; ECG electrocardiogram ; HR heart rate ; MHR mean heart rate ; Q10 temperature coefficient ; Ta ambient temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We compared the developmental patterns of mean heart rate in Larus crassirostris and L. schistisagus embryos and chicks with other avian species of different hatchling developmental modes. We proposed that, since mean heart rate is inversely related to fresh egg mass in all birds, larger species reached a higher fraction of their hatchling mean heart rate by the end of the early phase of incubation and that heart rate contributions to supplying the increasing metabolic demands during mid and late incubation phases were less important than in smaller avian species. Mean heart rate was essentially independent of age throughout the mid-incubation phase (33% of normalised incubation until pipping), but increased with time during early (L. schistisagus only investigated) and late-incubation phases in both species. The O2 pulse of L. schistisagus embryos and chicks increased linearly with yolk-free body mass (log-log) after the early-phase of incubation until shortly before pipping, but was independent of body mass in the periods before and after. We conclude that a high heart rate in this first period is probably more important for increasing the circulation of nutrients to the embryo at a stage when extra-embryonic circulation to the yolk sac is limited by the size of the growing area vaculosa. Furthermore, large increases in mean heart rate during the late-incubation phase are probably important for increasing the cardiac output to hatching levels with onset of endothermy. However, mean heart rate is stable over the mid-incubation while O2 pulse increases, suggesting that increases in stroke volume and other circulatory adjustments may be entirely responsible for the largest increases in O2 transport during incubation of large avian species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003600000120
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  • 4
    Electronic Resource
    Electronic Resource
    Permeability of human venous endothelial cell monolayers perfused in microcarrier cultures: Effects of flow rate, thrombin, and cytochalasin D (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 149 (1991), S. 88-99 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have applied a multiple isotope dilution technique to examine junctional permeability of human umbilical vein endothelial cells (HUVEC) in vitro. Primary cultures were grown to confluence on porous Cytodex-3 microcarrier beads, packed into 0.3 ml columns (3 × 106 cells) and perfused at varying flow rates (0.3-1.2 ml/min) with HEPES-buffered Tyrodes solution containing unlabeled cyanocobalamin, insulin, and albumin. Columns were challenged periodically with mixtures of radioactive tracers of different molecular size. Permeability to 22Na+, [57Co]cyanocobalamin (1.3 kD), [125l]insulin (6 kD) or [125l]albumin (66 kD) was assessed relative to [131l]lgG (160 kD, impermeant reference tracer) by comparing column elution profiles. Although the single passage extraction of [125l]albumin by beads alone approximated 40%, the presence of confluent HUVEC rendered these beads effectively impermeable to albumin. High junctional extractions were measured for cyanocobalamin (0.79 ± 0.02, n = 28) and insulin (0.51 ± 0.05, n = 14) in cultures perfused at 0.3-0.4 ml/min, and tracer extraction decreased as perfusion rates increased. Permeability coefficients for cyanocobalamin (9.66 × 10-5 cm/s) and insulin (4.18 × 10-5 cm/s) increased significantly during perfusion with thrombin (10 U/ml) or cytochalasin D (1 μg/ml), whereas permeability to albumin (0.39 × 10-5 cm/s) remained unchanges. Morphological studies, using the glycocalyx stain ruthenium red, revealed that thrombin or cytochalasin D increased the penetration of the stain into junctions between endothelial cells.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041490112
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