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  • Artikel: DFG Deutsche Nationallizenzen  (6)
  • Organic osmolytes  (4)
  • Cell & Developmental Biology  (2)
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  • Artikel: DFG Deutsche Nationallizenzen  (6)
Materialart
Erscheinungszeitraum
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular medicine 68 (1990), S. 1091-1095 
    ISSN: 1432-1440
    Schlagwort(e): Organic osmolytes ; Rat kidney ; Diabetes insipidus ; Diabetes mellitus ; Hormone treatment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Four organic small molecules belonging to the chemical groups of trimethylamines (betaine and glycerophosphorylcholine) and polyols (sorbitol and inositol) have been shown to act as organic osmolytes in the kidney. When measured along the corticopapillary axis, each exhibits a specific distribution pattern, indicating a specific localization and function. Studying their behaviour under vasopressin treatment in diabetes insipidus rats and after insulin treatment in diabetes mellitus rats confirmed this conclusion: AVP led to a steady increase of sorbitol and glycerophosphorylcholine over 7 days with no effect on inositol levels. Insulin treatment of diabetic rats, on the other hand, decreased sorbitol with a concomitant increase in glycerophosphorylcholine, again without any effect on tubular inositol concentrations. From this and in vitro studies it can be concluded that both hormones act by indirect mechanisms which alter interstitial osmolality. This in turn leads to a change in tubular osmolyte synthesis, uptake and release rates. In addition, the concentrations of the respective precursors glucose and choline influence the formation rates of sorbitol and betaine.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular medicine 66 (1988), S. 843-848 
    ISSN: 1432-1440
    Schlagwort(e): Renal papillary cells ; Cell electrolytes ; Osmoadaptation ; Organic osmolytes ; Electron microprobe analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The cells of the renal papilla are subject to extreme variations in extracellular tonicity. To obtain more insight into the mechanisms whereby these cells adapt osmotically to these unique environmental conditions, elements were measured in individual cells of the rat renal papilla in antidiuresis and after prolonged furosemide administration. In antidiuresis cell sodium, chloride and potassium concentrations did not differ fundamentally from those observed in tubule cells exposed to isotonic surroundings such as in proximal tubule cells. The marked fall in extracellular electrolyte concentrations induced by furosemide was paralleled by a far less pronounced decline in intracellular sodium, chloride and potassium concentrations. These data indicate that papillary cells achieve osmoadaptation to widely differing extracellular tonicities mainly by varying the intracellular concentrations of osmotically active substances other than inorganic electrolytes. Since high concentrations of organic osmolytes (sorbitol, inositol, glycerophosphorylcholine and other trimethylamines) have been detected in the papilla and since the tissue contents of these compounds have been shown to vary in parallel with urine osmolality, it may be concluded that metabolically inert, organic osmolytes play a dominant role in the osmoregulation of renal papillary cells.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Pflügers Archiv 436 (1998), S. 814-827 
    ISSN: 1432-2013
    Schlagwort(e): Key words Antidiuresis ; Diuresis ; Heat shock proteins ; Ionic strength ; Organic osmolytes ; Osmotic stress ; Renal medulla
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Cells of the renal medulla, which are exposed under normal physiological conditions to widely fluctuating extracellular solute concentrations, respond to hypertonic stress by accumulating the organic osmolytes glycerophosphorylcholine (GPC), betaine, myo-inositol, sorbitol and free amino acids. Increased intracellular contents of these osmolytes are achieved by a combination of increased uptake (myo-inositol and betaine) and synthesis (sorbitol, possibly GPC), decreased degradation (GPC) and reduced osmolyte release. In the medulla of the concentrating kidney, accumulation of organic osmolytes, which do not perturb cell function even at high concentrations, allows the maintenance of ”normal” intracellular concentrations of inorganic electrolytes. Adaptation to decreasing extracellular solute concentrations, e.g. diuresis, is achieved primarily by activation of pathways allowing the efflux of organic osmolytes, and secondarily by inactivation of production (sorbitol) and uptake (betaine, myo-inositol) and stimulation of degradation (GPC). Apart from modulation of the osmolyte content, osmolality-dependent reorganization of the cytoskeleton and expression of specific stress proteins (heat shock proteins) may be further, as yet poorly characterized, components of the regulatory systems involved in the adaptation of medullary cells to osmotic stress.
    Materialart: Digitale Medien
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  • 4
    ISSN: 1432-2013
    Schlagwort(e): Key words MDCK cells ; Hypertonic stress ; NaCl ; Urea ; Organic osmolytes ; Heat shock proteins ; Cell viability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  In antidiuresis, the cells of the renal medulla are exposed to high extracellular concentrations of NaCl and urea. Since urea equilibrates with the intracellular compartment and is known to perturb intracellular macromolecules, high urea concentrations may well disturb the structure and function of cell proteins. Two types of organic substances are believed to counteract the adverse effects of high intracellular urea concentrations: specific organic osmolytes of the trimethylamine family [betaine and glycerophosphorylcholine (GPC)], which accumulate in renal medullary cells during prolonged periods of antidiuresis and cytoprotective heat shock proteins (HSPs), the tissue content of two of which (HSPs 27 and 72) is much higher in the inner medulla than in the iso-osmotic renal cortex. To evaluate the contribution of trimethylamines and HSPs to cytoprotection in the presence of high urea concentrations, the effect of HSP induction and osmolyte accumulation prior to exposure to high urea concentrations was examined in Madin-Darby canine kidney (MDCK) cells. Accumulation of organic osmolytes and synthesis of HSP27 and HSP72 was initiated by hypertonic stress (increasing the osmolality of the medium from 290 to 600 mosmol/kg H2O by NaCl addition). Control, non-conditioned cells remained in the isotonic medium for the same period. Upon subsequent exposure to an additional 600 mM urea in the medium for 24 h, 90% of the osmotically conditioned cells but only 15% of non-conditioned cells survived. The HSP72 and trimethylamine contents of the NaCl-conditioned MDCK cells, but not HSP27 content, correlated positively with cell survival. To separate the effects of organic osmolytes and HSP72, chronically NaCl-adapted MDCK cells were returned to isotonic medium for 1 or 2 days, so depleting them of trimethylamine osmolytes. HSP72, with its longer half life, remained elevated. Subsequent exposure of these cells to 600 mM urea in the medium resulted in about 80% survival. These results suggest that in MDCK cells and probably in the renal medulla, HSP72 and perhaps additional protective factors contribute substantially to the resistance against high urea concentrations.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 158 (1967), S. 111-113 
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: An investigation into the source of the cells present in the endometrial arteries of the pregnant Macaque is presented. By comparing the levels of sex chromatin found in these cells with those in fetal cytotrophoblast and in maternal endometrial stroma it was possible to determine that they are essentially of fetal origin.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Developmental Dynamics 204 (1995), S. 219-227 
    ISSN: 1058-8388
    Schlagwort(e): Cdx-2 ; Homeobox ; Placental patterning ; Gut ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Three mouse homologues of the Drosophila homeotic gene Caudal (Cad) have been described. They are currently designated Cdx-1, Cdx-2, and Cdx-4. Cdx-1 and 2 are both strongly expressed in the adult mid- and hindgut, while Cdx-1 and 4 have been shown to be activated in the embryonic primitive streak. Using a polyclonal antibody against a fusion protein containing the amino terminal 109 amino acids of murine Cdx-2, we here describe the topographical location of the gene product from early cleavage to 12.5 days of embryonic development. Cdx-2 expression begins at 3.5 days and is confined to the trophectoderm, being absent from the inner cell mass. Subsequently, staining is located in the extra-embryonic ectoderm adjacent to the epiblast, but sparing the more superficially placed polar, as well as the mural trophoblastic cells. Continuing expression in the fetal membranes involves the chorion, the allantoic bud, and, at even later stages, the spongiotrophoblast. From 8.5 days, Cdx-2 begins to be expressed in embryonic tissues, principally (unlike Cdx-1) in the posterior part of the gut from its earliest formation, as well as in the tail bud and in the caudal part of the neural tube. Cdx-2 is, therefore, transcribed well before any other membrane of the Cad homologue group and of the related Hox-C group; its expression in the extra-embryonic membranes and in the hindgut reflects the phylogenetic relationship between the cloaca and the chorio-allantois and suggests the possibility that homeobox genes may be involved in placental development and/or patterning. © 1995 wiley-Liss, Inc.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
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