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  • Ouabain  (3)
  • meniscusreconstruction  (2)
  • 1
    ISSN: 1432-2013
    Schlagwort(e): Goldfish intestine ; Ouabain ; Transepithelial potential difference ; Transepithelial resistance ; Na+, K+, Cl− ; Cellular volume ; Sugars
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract 1. In goldfish intestine (perfused unstripped segments and mucosal strips) the serosal addition of ouabain (10\t-4 M) resulted in a vanishment of the transepithelial potential difference and in a continuous increase in transepithelial resistance. 2. Incubation of mucosal strips with ouabain resulted in an increase in sodium content which was greater than the decrease in potassium content. The resulting increase in cation content was accompanied by an increase in chloride content and an increase in water content. 3. Histological examination showed that exposure to ouabain resulted in a swelling of the epithelial layer as compared to the control situation. 4. The ouabain induced resistance increase is greater in the presence of glucose, 3-OMG or fructose than in the presence of mannitol. Phlorizin (10\t-4 M) inhibits the extra resistance increase induced by mucosal glucose but is without effect on the fructose induced extra resistance increase. The initial velocity and the magnitude of the glucose induced extra resistance increase depends on the glucose concentration. 5. The results suggest that in goldfish intestine ouabain induces cellular swelling with a concomitant collapse of the lateral intercellular spaces, which is the cause of the increased transepithelial resistance. The additional changes in resistance induced by sugars suggest that the cell membrane is more permeable to glucose, 3-OMG and fructose than to mannitol. The resulting changes in osmotically active material within the epithelial cell influence the cross-sectional area and consequently the conductivity of the paracellular shunt pathway. The hypothesis that these sugars do not induce a resistance change in the absence of ouabain is discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Pflügers Archiv 392 (1981), S. 57-66 
    ISSN: 1432-2013
    Schlagwort(e): Goldfish intestinal mucosa ; Ouabain ; Cell volume regulation ; Anaerobic conditions ; Low chloride conditions ; Osmolarity and ion content
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract 1. Ion and water content of goldfish intestinal mucosa, stripped free from muscular layers were measured under various incubation conditions. 2. Ouabain induces an increase in cation content that is electrically compensated for by chloride. The increase in solute content is accompanied by an increase in water content. 3. When extracellular chloride is partially replaced by sulphate, ouabain does induce cell shrinkage. 4. Anoxia induces a rapid increase in cell volume that is restored by oxygenation of the incubation solution. Ouabain prevents the restoration of volume. 5. It is concluded that the classical ouabain-sensitive Na/K pump participates in the maintenance of cellular volume. We suggest that the constancy in volume after ouabain poisoning as is reported for many tissues might be due to a low chloride conductance of its membranes. 6. Anisotonic media (range: 0.6–1.2 isotonicity), made by variation in mannitol concentration, induced changes in cell water content that deviates from the simplified van 't Hoff equation by about 10%. No change in water content after the initial increase was found. 7. We conclude that goldfish enterocytes do not possess a mechanism for rapid volume readjustment.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Pflügers Archiv 392 (1981), S. 67-71 
    ISSN: 1432-2013
    Schlagwort(e): Goldfish intestinal mucosa ; Ouabain ; Transepithelial resistance ; Cell volume ; Hypotonicity ; Anaerobic conditions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract 1. The ouabain-induced increase in transmural resistance of goldfish intestinal mucosa stripped free from underlying muscular layers is analysed by comparing the resistance increase in normal and in low chloride saline, the resistance increase induced by anaerobic conditions and the resistance increase provoked by hypotonicity. 2. It is concluded that the collapse of the lateral intercellular space is the prime reason for the resistance increase and that the lateral intercellular space is maintained dilated by a ouabain-sensitive solute transport mechanism. 3. This mechanism can be either a rheogenic or a neutral Na/K-pump. In the latter case additional conditions have to be specified concerning values for ion concentrations in the lateral intercellular space and in the unstirred layer adjacent to the luminal membrane. 4. There are no indications for a chloride dependent mechanism involved in the maintenance of the width of the lateral intercellular spaces in the goldfish intestinal mucosa.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 1435-1536
    Schlagwort(e): Porousmaterials ; foams ; biodegradablepolyurethanes ; meniscusreconstruction ; freeze-drying ; saltleaching
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract Porous biodegradable poly(urethanes) for reconstructing menisci have been prepared using two different combinations of techniques: freeze-drying/salt-leaching and in-situ polymerization/salt-leaching. Using these methods, homogenous porous materials with a controllable and reproducible morphology can be prepared. The materials were made of three different poly(urethanes): a methylenediphenyldiisocyanate-based polyurethane, a lysine diisocyanate-based poly(urethane), and a poly(ɛ-caprolactone)-based poly(urethane). The compressive stress-strain behavior of the Estane foams was determined. Foams made by the freeze-drying/salt-leaching technique implanted in dogs showed healing and good ingrowth of fibrocartilaginous tissue.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    ISSN: 1435-1536
    Schlagwort(e): Porousmaterials ; biodegradablefoams ; meniscusreconstruction ; macroporesize ; interconnectedpores ; porevolume
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract Several series of porous, biodegradable PU/PLLA foams were used for meniscus reconstruction in dogs. PLLA-fiber reinforced PU/PLLA composites, PU/PLLA, and PU foams were implanted in severe meniscus lesions. The healing process was initiated as a result of blood vessels′ and other cells′ ingrowth into these porous materials. To accomplish good ingrowth of fibrocartilaginous tissue, the materials should have interconnected macropores of 200–300μn with a high total pore volume. PLLA fibers were used to reinforce the materials, but seem to retard the degradation process and the ingrowth of fibrocartilaginous tissue.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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