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  • Springer  (53)
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  • 1
    Electronic Resource
    Electronic Resource
    HCO3 − Transport in a Mathematical Model of the Pancreatic Ductal Epithelium (2000)
    Springer
    The journal of membrane biology 176 (2000), S. 77-100 
    Details
    ISSN: 1432-1424
    Keywords: Key words: Pancreatic duct cells — Mathematical model — HCO−3 secretion — Cl− secretion — Cystic fibrosis transmembrane conductance regulator
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract. We have used computer modeling to investigate how pancreatic duct cells can secrete a fluid containing near isotonic (∼140 mm) NaHCO3. Experimental data suggest that NaHCO3 secretion occurs in three steps: (i) accumulation of HCO− 3 across the basolateral membrane of the duct cell by Na(HCO3) n cotransporters, Na+/H+ exchangers and proton pumps; (ii) secretion of HCO− 3 across the luminal membrane on Cl−/HCO− 3 antiporters operating in parallel with Cl− channels; and (iii) diffusion of Na+ through the paracellular pathway. Programming the currently available experimental data into our computer model shows that this mechanism for HCO− 3 secretion is deficient in one important respect. While it can produce a relatively large volume of a HCO− 3-rich fluid, it can only raise the luminal HCO− 3 concentration up to about 70 mm. To achieve secretion of 140 mm NaHCO3 by the model it is necessary to: (i) reduce the conductive Cl− permeability and increase the conductive HCO− 3 permeability of the luminal membrane of the duct cell, and (ii) reduce the activity of the luminal Cl−/HCO− 3 antiporters. Under these conditions most of the HCO− 3 is secreted via a conductive pathway. Based on our data, we propose that HCO− 3 secretion occurs mainly by the antiporter in duct segments near the acini (luminal HCO− 3 concentration up to ∼70 mm), but mainly via channels further down the ductal tree (raising luminal HCO− 3 to ∼140 mm).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00232001077
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  • 2
    Electronic Resource
    Electronic Resource
    Transient Swelling of Salivary Acinus Induced by Acetylcholine Stimulation: Water Secretion Pathway in Rat Submandibular Gland (1998)
    Springer
    The journal of membrane biology 161 (1998), S. 287-296 
    Details
    ISSN: 1432-1424
    Keywords: Key words: Paracellular pathway — Osmotic flow — Salivary secretion — Submandibular gland — Cell volume
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract. The volume changes of isolated acini and acinar cells from rat submandibular glands were measured from digitized images recorded upon stimulation of acetylcholine (ACh) or reduction of the perfusate osmolarity and water secretion pathway in salivary gland was studied. When acinus is exposed to a hyposmotic solution, water flows into the acinar cells and into the lumen via acinar epithelia. If the water enters the lumen chiefly via the cells, the swelling of the lumen would follow the same time course as the cell swelling or slower. The results show that reduction of the perfusate osmolarity evoked a transient increase followed by a gradual increase in the volume of unstimulated acinus, while it evoked only a gradual increase in the volumes of unstimulated acinar cells. Thus, the time course of the acinar swelling is faster than that of the acinar cell swelling. Reduction of the perfusate osmolarity also evoked a transient swelling in ACh stimulated acini. When acinus is stimulated by ACh, water also flows into the lumen via acinar epithelia according to the osmotic gradient which was generated by the active electrolyte transport of acinar cells. If the water enters the lumen chiefly from the cells, there would be no overall change in acinar volume. The results show that stimulation of ACh (5 μm) evoked a transient increase followed by a gradual decrease in the volume of the acinus, while it evoked only a decrease in the volume of acinar cells. Video-enhanced optical microscopy exhibited that ACh stimulation caused transient swelling of the luminal space, prior to causing the volume of acinar cells to decrease and the transient swelling of the lumen followed the same time course as that of acinus. Thus, the transient acinar swelling is explained by the transient swelling of luminar volume. These results suggest that water is probably drawn into the lumen from interstitial space directly in the salivary acinus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002329900335
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  • 3
    Electronic Resource
    Electronic Resource
    A Mathematical Model of the Pancreatic Ductal Epithelium (1996)
    Springer
    The journal of membrane biology 154 (1996), S. 53-67 
    Details
    ISSN: 1432-1424
    Keywords: Key words: Pancreatic duct — Mathematical model — HCO−3 secretion — Intracellular pH regulation — Cystic fibrosis transmembrane conductance regulator
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract. A mathematical model of the HCO− 3-secreting pancreatic ductal epithelium was developed using network thermodynamics. With a minimal set of assumptions, the model accurately reproduced the experimentally measured membrane potentials, voltage divider ratio, transepithelial resistance and short-circuit current of nonstimulated ducts that were microperfused and bathed with a CO2/HCO− 3-free, HEPES-buffered solution, and also the intracellular pH of duct cells bathed in a CO2/HCO− 3-buffered solution. The model also accurately simulated: (i) the effect of step changes in basolateral K+ concentration, and the effect of K+ channel blockers on basolateral membrane potential; (ii) the intracellular acidification caused by a Na+-free extracellular solution and the effect of amiloride on this acidification; and (iii) the intracellular alkalinization caused by a Cl−-free extracellular solution and the effect of DIDS on this alkalinization. In addition, the model predicted that the luminal Cl− conductance plays a key role in controlling both the HCO− 3 secretory rate and intracellular pH during HCO− 3 secretion. We believe that the model will be helpful in the analysis of experimental data and improve our understanding of HCO− 3-transporting mechanisms in pancreatic duct cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002329900132
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  • 4
    Electronic Resource
    Electronic Resource
    Removal of famotidine by haemodialysis in elderly anuric patients (1990)
    Springer
    European journal of clinical pharmacology 38 (1990), S. 313-314 
    Details
    ISSN: 1432-1041
    Keywords: famotidine ; anuric patients ; haemodialysis ; H2-receptor antagonist ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of haemodialysis on the pharmacokinetics of oral famotidine has been studied in five elderly anuric patients. Famotidine 20 mg was administered in a cross-over design to patients on and not on haemodialysis. The elimination rate constant of haemodialysis (k) was 4.6-fold larger than the systemic elimination rate constant (ke). Although the mean maximum serum concentration of famotidine during haemodialysis (141.5 ng·ml−1) was not significantly lower than that without haemodialysis (195.6 ng·ml−1), the AUC up to 5 h during haemodialysis was significantly decreased to 58.1% of the value without it. The data suggest that famotidine is dialysable by haemodialysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315039
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  • 5
    Electronic Resource
    Electronic Resource
    Muscle cramps and elevated serum creatine phosphokinase levels induced by β-adrenoceptor blockers (1995)
    Springer
    European journal of clinical pharmacology 48 (1995), S. 29-34 
    Details
    ISSN: 1432-1041
    Keywords: β-Adrenoceptor blocker ; intrinsic sympathomimetic action ; muscle cramps ; CPK ; CPK-MB ; propanolol ; carteolol ; metoprolol ; arotinolol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract We have assessed the propensity of β-adrenoceptor blockers to cause muscle cramps and to raise the serum creatine phosphokinase (CPK) level in 78 patients with essential hypertension. After a control period, a β-adrenoceptor blocker without intrinsic sympathomimetic activity (ISA; propranolol, metoprolol or arotinolol) was administered for three months. Thereafter, the patients were randomised to receive a β-adrenoceptor blocker with ISA (pindolol or carteolol) for three months or a β-adrenoceptor blocker without ISA for a further three months. This pattern was continued until all β-adrenoceptor blockers had been given. At the end of each period, CPK and CPK-MB levels were measured. Of the 78 subjects, muscle cramps occurred in 27 during treatment with pindolol and 32 during treatment with carteolol. No complaints were made by subjects treated with propranolol and arotinolol, but muscle cramps were reported in 2 treated with metoprolol. While muscle cramps were caused both by pindolol and carteolol in 16 subjects, they were caused by either of these drugs in the remainder of the subjects. Muscle cramp occurred mainly in the calves when the patients were in bed at night. Serum CPK and CPK-MB levels increased significantly during treatment with pindolol (control period vs pindolol, CPK=96 vs 133 IU · ml−1, CPK-MB=14 vs 18 IU · ml−1) or carteolol (CPK=117 IU · ml−1, CPK-MB=18 IU · ml−1) while the levels during treatment with propranolol, arotinolol and metoprolol did not change from those in the control period. The change in serum CPK during treatment with carteolol or pindolol was significantly correlated with the control serum CPK level. No correlation was observed between muscle cramps and serum CPK level. There were individual differences in the severity of muscle cramps, with some subjects complaining frequently of severe muscle cramps. Because muscle cramps are frequently experienced at night, they disturb sleep and lower the quality of life in patients. This problem should be considered during treatment with β-adrenoceptor blockers with ISA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00202168
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  • 6
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of famotidine in elderly patients with and without renal insufficiency and in healthy young volunteers (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 517-520 
    Details
    ISSN: 1432-1041
    Keywords: famotidine ; H2-receptor antagonist ; renal insufficiency ; old age pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of the H2-receptor antagonist famotidine, after oral administration of a 20 mg tablet, has been studied in 10 elderly patients with normal renal function (CLCR≧59 ml·min−1, Mean=80 ml·min−1), 5 elderly patients with renal insufficiency (CLCR≦38 ml·min−1, Mean=15 ml·min−1), and 6 healthy young volunteers. Elimination half-life in the elderly patients with renal insufficiency was significantly prolonged compared to the elderly patients with normal renal function and the young volunteers. The correlation coefficient between creatinine clearance and the elimination rate constant of famotidine was 0.672. Mean urinary recovery of unchanged drug up to 24 h in the young volunteers was 44%. The mean renal clearance of famotidine in the young volunteers (270 ml·min−1) was substantially greater than the creatinine clearance, 128 ml·min−1, which suggests the possibility of tubular secretion of famotidine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558079
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  • 7
    Electronic Resource
    Electronic Resource
    Epidermal growth factor stimulates proliferation of rat hepatoma cells producing α-fetoprotein (1979)
    Springer
    Cellular and molecular life sciences 35 (1979), S. 1660-1661 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Epidermal growth factor stimulated both [3H]thymidine uptake and proliferation of rat AH66 hepatoma cells. However, the increase in cell number was not accompanied by a proportional increase in the levels of α-fetoprotein of the culture media. The effects of EGF on the cell proliferation were antagonized by N6, O2′-dibutyryl cAMP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01953254
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  • 8
    Electronic Resource
    Electronic Resource
    Reduction to one half in dietary intake of cadmium and lead among Japanese populations (1994)
    Springer
    Bulletin of environmental contamination and toxicology 52 (1994), S. 196-202 
    Details
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00198488
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  • 9
    Electronic Resource
    Electronic Resource
    Localization of blood coagulation factors and fibrinolysis factors within lymphoid germinal centers in human lymph nodes (1991)
    Springer
    Histochemistry and cell biology 96 (1991), S. 123-127 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The presence of nineteen blood coagulation factors and fibrinolysis factors was immunohistochemically evaluated in human lymph node germinal centers (GCs). Twelve of these factors were detected within lymphoid GCs. The predominant pattern was dendritic with occasional crescent-shaped, ring-shaped or ‘moth-eaten’ appearance. Immunostains of factor VIII-related antigen, factor I, protein C, tetranectin, antithrombin III, type 2-plasminogen activator inhibitor, and α2-plasmin inhibitor were almost entirely absent from GCs, although they reacted in vascular wall and lumen, respectively. The immunostaining to high molecular weight kininogen, kallikrein, factors XII, X, V, II, XIIIa, XIIIs, plasminogen, tissue-plasminogen activator, and type 1-plasminogen activator inhibitor more frequently revealed a positive dendritic pattern. Immuno-electron microscopy demonstrated factor X and factor XIIIa attached to the cell surfaces of lymphocytes, macrophages, and follicular dendritic cells (FDCs); and in the intercellular space within GCs, especially attached to the labyrinthine-like structure of FDCs. No reaction products were observed in the perinuclear cisternae and rough endoplasmic reticulum in either lymphocytes or FDCs. Our data demonstrate that human lymphoid GCs really contain some of the proteins related to the blood coagulation and fibrinolysis cascades.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315982
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  • 10
    Electronic Resource
    Electronic Resource
    Synthese von alternierenden Copolymalonamiden durch Ringöffnungs-Polyaddition von Bismalonimid mit Diaminen (1974)
    Springer
    Colloid & polymer science 252 (1974), S. 181-181 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01555656
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