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  • Electronic Resource  (4)
  • 1990-1994  (4)
  • 1955-1959
  • 1992  (4)
  • Life and Medical Sciences  (2)
  • Scaphognathite  (2)
  • supercritical fluid chromatography
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  • Electronic Resource  (4)
Years
  • 1990-1994  (4)
  • 1955-1959
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  • 1
    Electronic Resource
    Electronic Resource
    Carapace movements aid air breathing in the semaphore crab, Heloecius cordiformis (Decapoda: Brachyura: Ocypodidae) (1992)
    Springer
    Journal of comparative physiology 162 (1992), S. 375-382 
    Details
    ISSN: 1432-136X
    Keywords: Air breathing ; Lung ventilation ; Scaphognathite ; Water circulation ; Carapace movements ; Crab, Heloecius
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary While on land and recirculating branchial water the Australian semaphore crab Heloecius cordiformis (Decapoda: Ocypodidae), a semi-terrestrial airbreathing mangrove crab, sequentially depresses and elevates its carapace in a regular pump-like manner. The functional role of these carapace movements in aerial oxygen consumption is investigated. Carapace immobilisation (reversible and non-injurious) did not appear to affect branchial water circulation. In “dry” crabs (branchial water removed) carapace immobilisation had no effect on the rate of oxygen consumption (VO2), heart rate or whole-body lactate (WBL) levels. In “wet” crabs (with branchial water) carapace immobilisation caused VO2 to drop by 38% from 81 to 46 μl O2 · g-1 · h-1, heart rate to decline by 32%, from 2.5 to 1.7 Hz, and WBL levels to increase over 2.5-fold, from 0.27 to 0.67 mg · g-1, after 3 h of carapace immobilisation. The (VO2) of carapace-immobilised crabs with branchial water was similar to lung-occluded crabs with branchial water. Severe hypoxia induced physiological responses similar to those of carapace-immobilised crabs with branchial water. After 3 h of severe hypoxia, heart rate had declined by 80%, from 2.2 to 0.43 Hz, and the incidence of carapace pumping slowed by 85%, from 2.4 to 0.37 cycles · min-1. It is concluded that in the absence of carapace movements branchial water in some way inteferes with lung ventilation. Under normal circumstances water circulation and lung ventilation are mutually exclusive processes (due to their singular dependence on the scaphognathites), yet in Heloecius these processes must be carried out simultaneously. Carapace movements may alleviate this conflict.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00260766
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Carapace movements associated with ventilation and irrigation of the branchial chambers in the semaphore crab, Heloecius cordiformis (Decapoda: Brachyura: Ocypodidae) (1992)
    Springer
    Journal of comparative physiology 162 (1992), S. 365-374 
    Details
    ISSN: 1432-136X
    Keywords: Carapace movements ; Lung ventilation ; Scaphognathite ; Water circulation ; Crab, Heloecius
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Carapace movements in crabs are briefly reviewed. While on land and recirculating branchial water, the Australian semaphore crab Heloecius cordiformis (Decapoda: Ocypodidae), a semi-terrestrial air-breathing mangrove crab, sequentially depresses and elevates its carapace relative to its thorax (0.5–1 mm excursion) in a regular pump-like manner. In quiescent crabs each carapace-pumping cycle lasts about 4 s; carapace depression takes 3 s and elevation 1 s. Carapace movements are brought about by pressures generated within the branchial chambers by the scaphognathites, probably in combination with carapace muscles. Carapace movements are associated with bilaterally synchronised scaphognathite activity. Unilateral scaphognathite activity was not observed. During normal forward recirculation of branchial water the scaphognathites beat at about 1.5 Hz (slow-forward pumping) and the lungs (epibranchial chambers) are not ventilated. In Heloecius, the lungs are not physically separated from the gills below by an anatomical barrier. Lung ventilation is accomplished during the following sequence of events: the carapace is lowered and the scaphognathites pump in a fast-forward mode at about 2.8 Hz. This activity preferentially pumps air out of the lungs and generates suction within the branchial chambers (4–10 cm H2O below ambient) which draws water from external body surfaces into the hypobranchial space below and around the gills. At the end of the carapace's downward travel the scaphognathites switch from fast-forward to fastreverse beating at about 4 Hz. This pumps air into the lungs and the carapace elevates. As a result, during carapace elevation the water which had previously been drawn into the branchial chambers by fast-forward pumping activity is released and flows out between the legs and into the abdominosternal cavity. When the carapace reaches its original resting or “up” position the scaphognathites switch from fast-reverse to slowforward beating to re-establish water recirculation through the branchial chambers. This cycle is subsequently repeated. In stationary crabs, there are 2 carapace-pumping cycles per minute, increasing to 14 per minute in active crabs (walking). When water is absent, the lungs are preferentially ventilated by slow-reverse scaphognathite pumping activity. Carapace movements do not occur in the absence of branchial water. Carapace pumping is thought to provide a mechanism which permits the scaphognathites to ventilate the lungs in the presence of recirculating branchial water, without this water interfering with lung ventilation or being lost to the environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00260765
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    A multiplanar anatomic study of the cervical proximal nerve roots and spinal nerves (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Clinical Anatomy 5 (1992), S. 433-440 
    Details
    ISSN: 0897-3806
    Keywords: anatomy ; spine ; sheath ; Life and Medical Sciences ; Miscellaneous Medical
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: An anatomic study focused on the proximal cervical spinal nerves has not been reported. Therefore, we dissected the cervical spinal nerves of three cadavers and examined stained sections in parasagittal and axial planes through the proximal cervical spinal nerves and root sheaths. These studies documented distinct segments of the spinal nerve which had not been completely described in the previous anatomic studies. The sheath originates from the dural sac as a common sleeve, divides into two sleeves, one containing the ventral root and one the dorsal root, and then distal to the dorsal root ganglion fuses again into one sleeve. A space, the interradicular cleft, separates the dorsal and ventral portions of the sleeve. The proximal segment of the spinal nerve proper distal to the dorsal root ganglion is composed of multiple small fascicles surrounded by a dense epineurium. The presence of an interradicular cleft in the cervical nerve root sheath and of fascicles in the cervical spinal nerve has significance for imaging of the cervical spinal nerves and for the pathogenesis of symptoms in cases of partial compression. © 1992 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ca.980050603
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Dihydropyridine calcium antagonist modulates cholesterol metabolism and eicosanoid biosynthesis in vascular cells (1992)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 48 (1992), S. 393-400 
    Details
    ISSN: 0730-2312
    Keywords: calcium channel blocker ; atherosclerosis ; LDL ; LDL-receptor ; vascular smooth muscle ; PGI2 ; cyclic AMP ; cyclooxygenase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Recent clinical studies have shown that calcium channel blockers can retard and possibly reduce the angiographic progression of coronary artery disease. Calcium channel blockers also inhibit dietary-induced atherosclerosis in animal models of this disease. In this study, we delineate potential cellular and molecular mechanisms by which nicardipine, a dihydropyridine calcium antagonist, may alter lipoprotein and cholesterol trafficking, affect the regulatory signal transduction pathways involved in accelerating cholesteryl ester (CE) catabolism in vascular smooth muscle cells, and modulate cell-cell interactions of vascular and inflammatory cells. We demonstrate in arterial smooth muscle cells that nicardipine increases (1) LDL binding, uptake, and degradation, (2) RNA transcript levels for the LDL receptor, (3) CE catabolic activity, (4) PGI2 release, and (5) RNA transcript levels for cyclooxygenase. Furthermore, nicardipine blocked cytokine-induced monocyte adhesion to endothelial cells and smooth muscle cells. Taken together, these findings support the hypothesis that nicardipine may function as an anti-atherosclerotic agent by promoting CE catabolism and cholesterol clearance and by reducing monocyte adhesion to the activated endothelium.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240480408
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    Paper (German National Licenses)
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