Bibliothek

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
  • 1
    Digitale Medien
    Digitale Medien
    EXOCYTOSIS OF LUNG SURFACTANT: From the Secretory Vesicle to the Air-Liquid Interface (2005)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Physiology 67 (2005), S. 595-621 
    Details
    ISSN: 0066-4278
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Medizin , Biologie
    Notizen: Exocytosis is fundamental in biology and requires an orchestra of proteins and other constituents to fuse a vesicle with the plasma membrane. Although the molecular fusion machinery appears to be well conserved in evolution, the process itself varies considerably with regard to the diversity of physico-chemical and structural factors that govern the delay between stimulus and fusion, the expansion of the fusion pore, the release of vesicle content, and, finally, its extracellular dispersion. Exocytosis of surfactant is unique in many of these aspects. This review deals with the secretory pathway of pulmonary surfactant from the type II cell to the air-liquid interface, with focus on the distinct mechanisms and regulation of lamellar body (LB) fusion and release. We also discuss the fate of secreted material until it is rearranged into units that finally function to reduce the surface tension in the lung.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.physiol.67.040403.102553
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    Fused cells of frog proximal tubule: I. Basic membrane properties (1987)
    Springer
    The journal of membrane biology 100 (1987), S. 43-51 
    Details
    ISSN: 1432-1424
    Schlagwort(e): frog kidney ; proximal tubule ; HCO 3 − transport ; K+ conductance ; Cl− conductance ; fusion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Summary Proximal tubular cells of the frog (Rana esculenta) kidney were fused within an isolated tubule portion to giant cells according to the polyethylene-glycol fusion method. Cell membrane potentials (V m ) were measured while cells were superfused with varioús experimental solutions. Rapid concentration stepchanges of different ions allowed to calculate the respective transference numbers (t ion). In some experiments the specific cell membrane resistances (R m ) were evaluated by measuringV m induced by short current pulses injected into the cell with a second electrode. The experiments reveal: i) Fused cells of the proximal tubule exhibit aV m of −49.5±1.6 mV (n=65). ii) Addition of glucose to the perfusate yields a transient depolarization, consistent with a rheogenic Na/glucose cotransport system. iii) In absence of organic substrates the whole cell membrane conductance is made up of K+ and HCO3, iv) There is a positive relationship betweenV m andtK+ and a negative relationship betweenV m andtHCO 3 − . v) HCO 3 − -inducedV m changes are attenuated or abolished when Na+ is replaced with choline+, consistent with a rheogenic Na+/HCO 3 − cotransport system. vi) Replacement of Na+ by choline+ depolarizesV m and increasesR m by about 50%; addition of 3 mmol/liter Ba2+ to the Na+-free perfusate increasesR m by about 58% compared to the initial control value. vii) There is no measurable cell membrane Cl− conductance. We conclude that fused cells of proximal tubule exert both luminal and peritubular membrane properties. In absence of organic substrates the cell membrane potential is determined by the HCO 3 − and K+ transport systems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02209139
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 3
    Digitale Medien
    Digitale Medien
    Chloride transport in the diluting segment of the K+ adapted frog kidney: Effect of amiloride and acidosis (1986)
    Springer
    Pflügers Archiv 407 (1986), S. S60 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Amiloride ; Cl− transport ; Diluting segment ; K+ conductance ; Adaptation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The hypothesis was tested whether amiloride and/or an acute acid load influence Cl− transport in the diluting segment of the isolated-perfused kidney of the K+ adapted frog (rana pipiens). Transepithelial resistance (luminal cable analysis) and Cl− net flux (Cl− sensitive microelectrodes) were evaluated at various concentrations of amiloride, at highpCO2 or low HCO 3 − in the kidney perfusate. Amiloride or an acute acid load increase transepithelial resistance. The resistance-change at given concentrations of amiloride is markedly enhanced under static head conditions, i. e. at low luminal NaCl concentrations. Amiloride or acidosis (highpCO2) reduce Cl− net reabsorption; combination of both potentiates this inhibitory effect. We conclude: an acute acid load acidifies the cell cytosol. This effect is aggravated dramatically after amiloride-induced inhibition of the luminal Na+/H+ exchanger. The luminal pH-sensitive K+ conductance decreases. This results in a depolarization of the cell membranes. Consequently, the peritubular electrochemical driving force for the exit step of Cl− (from cell to blood) dissipates. Therefore, Cl− net reabsorption is blunted.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00584931
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 4
    Digitale Medien
    Digitale Medien
    Activation of luminal Na+/H+ exchange in distal nephron of frog kidney (1987)
    Springer
    Pflügers Archiv 408 (1987), S. 609-614 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Aldosterone ; Spironolactone ; H+ transport ; Frog kidney ; Distal tubule
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Increased chronic intake of K+ induced H+ and K+ secretion in amphibian distal tubule, paralleled by an elevation of plasma aldosterone. The present experiments test whether the mineralocorticoid hormone is responsible for the alteration of ion transport. The blood capillaries of the isolated kidneys of NaCl-adapted (i.e. aldosterone-suppressed)Rana pipiens were perfused with HEPES-buffered amphibian Ringer solution (pH 7.8). Limiting intraluminal pH (pH1u) was measured continuously with pH-sensitive microelectrodes while aldosterone (3·10−7 to 3·10−6 mol/l) was applied in the peritubular perfusate. Concomitant with a decrease of the lumen-positive transepithelial potential (V te) from 8.5±1.1 mV to 4.0±0.6 mV pH1u dropped from 7.73±0.02 to a new steady-state value of 7.17±0.05 within 60 to 180 min of aldosterone administration. Significant luminal acidification occurred already 20 min after application of aldosterone. Luminal addition of 10−3 mol/l amiloride reversed luminal acidification to a pH1u of 7.68±0.04; at the same timeV te recovered partially. Pretreatment of the distal tubules with spironolactone prevented the aldosterone-induced acidification of the tubule fluid. We conclude that in early distal tubule of the amphibian kidney aldosterone — after interaction with cytoplasmic receptors — activates the luminal, amiloride-inhibitable Na+/H+ exchanger. This mechanism could explain enhanced H+ secretion found in the K+ adapted animal.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00581163
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 5
    facet.materialart.
    Unbekannt
    The Feasibility of Hyperbolical Doubt (1969)
    Minneapolis : Periodicals Archive Online (PAO)
    Philosophical Studies. 20:5 (1969:Oct.) 
    Details
    ISSN: 0031-8116
    Thema: Philosophie
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:6193-1969-020-05-000002
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 6
    facet.materialart.
    Unbekannt
    PARESIS AND THE ALLEGED ASYMMETRY BETWEEN EXPLANATION AND PREDICTION (1966)
    Oxford : Periodicals Archive Online (PAO)
    The British journal for the philosophy of science. 17 (1966:May-1967:Feb.) 313 
    Details
    ISSN: 0007-0882
    Thema: Allgemeine Naturwissenschaft , Philosophie
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:4064-1966-017-00-000013
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 7
    Digitale Medien
    Digitale Medien
    Ca2+ transport in diluting segment of frog kidney (1987)
    Springer
    Pflügers Archiv 410 (1987), S. 63-68 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Ca2+ Transport ; Diluting segment ; Furosemide ; Frog kidney ; Ca2+ sensitive microelectrodes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In the isolated-perfused frog (Rana pipiens) kidney the question of whether transepithelial transport of Ca2+ is a passive voltage driven process or involves active mechanisms was investigated. With conventional and ion-sensitive microelectrodes transepithelial electrical and electrochemical potential differences were measured. Luminal activities and transepithelial net fluxes of Ca2+ and Cl− were evaluated. Different transepithelial electrical voltages in a wide range (+20 to−4 mV) were generated by “chemical voltage clamping” and the dependence of Ca2+ net fluxes on these voltages investigated. The hormonal control of both Cl− and Ca2+ transport was studied by evaluating the effect of the cell-permeable cAMP analogue, db-cAMP and of the adenylate cyclase stimulator, forskolin. The experiments reveal that: (a) Ca2+ is reabsorbed along the diluting segment of frog kidney. (b) Ca2+ reabsorption is inhibited by furosemide because of the elimination of the transepithelial voltage. (c) There is a direct relationship between transepithelial voltage and Ca2+ reabsorption. (d) Neither Cl− nor Ca2+ reabsorption are affected by db-cAMP or forskolin. We conclude that Ca2+ reabsorption is passive, driven by the lumen-positive transepithelial voltage. It most likely occurs via the paracellular shunt pathway.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00581897
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 8
    Digitale Medien
    Digitale Medien
    The feasibility of hyperbolical doubt (1969)
    Springer
    Philosophical studies 20 (1969), S. 70-73 
    Details
    ISSN: 1573-0883
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Philosophie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02316967
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...