ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Differential binding of thyroxine and triiodothyronine to acidic isoforms of thyroid hormone binding globulin in human serum (1988)
    s.l. : American Chemical Society
    Biochemistry 27 (1988), S. 3624-3628 
    Details
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/bi00410a015
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Theoretical consideration of drug distribution kinetics in a noneliminating organ: Comparison between a “homogeneous (well-stirred)” model and “nonhomogeneous (tube)” model (1985)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 13 (1985), S. 265-287 
    Details
    ISSN: 1573-8744
    Keywords: drug distribution kinetics ; noneliminating organ ; homogeneous model ; well-stirred model ; nonhomogeneous model ; tube model ; tissue-to-plasma partition coefficient ; tissue-to-blood partition coefficient ; physiological pharmacokinetics ; redistribution clearance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Drug distribution kinetics in a noneliminating organ or tissue has been mathematically examined. The homogeneous (well-stirred) model regards the noneliminating organ or tissue as a homogeneous compartment in which the drug is equilibrated with that in the blood leaving the organ or tissue. The nonhomogeneous (tube) model views the noneliminating organ or tissue as comprising a number of parallel cylindrical tubes containing binding sites distributed homogeneously along these tubes. These two models are examined, considering the pseudo-distribution equilibrium phase after bolus injection and a linear binding condition. Although both models predict a similar tissue distribution under a variety of conditions, significant differences exist in the predictions of various pharmacokinetic parameters as a function of the drug distribution, such as blood flow, organ volume, slope of the terminal phase, and the tissue-to-blood partition coefficients. The predictability and limitations of these two models are explored. Distribution characteristics of the two models are also examined for adriamycin, actinomycin D, tetrachlorobiphenyl, hexachlorobiphenyl, digoxin, and ethoxybenzamide; no difference is observed. It is concluded that the assumption of a homogeneous (well-stirred) compartment is suitable for describing the drug distribution kinetics of these drugs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01065656
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    In Vivo and in Vitro Blood–Brain Barrier Transport of 3-Hydroxy-3-Methylglutaryl Coenzyme A (HMG-CoA) Reductase Inhibitors (1994)
    Springer
    Pharmaceutical research 11 (1994), S. 305-311 
    Details
    ISSN: 1573-904X
    Keywords: pravastatin ; lovastatin ; simvastatin ; 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor ; blood–brain barrier (BBB) transport ; brain perfusion ; cultured brain capillary endothelial cell ; central nervous system (CNS) side effect ; lipophilicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Among the HMG-CoA reductase inhibitors, lovastatin and simvastatin have central nervous system (CNS) side effects, such as sleep disturbance, whereas pravastatin does not. This difference in CNS side effects may be due to a difference in blood–brain barrier (BBB) permeability among these inhibitors. To test this hypothesis, we compared the BBB transport ability of HMG-CoA reductase inhibitors by using an in vivo brain perfusion technique in rats and an in vitro culture system of bovine brain capillary endothelial cells. The in vivo BBB permeability coefficients of the lipophilic inhibitors, [14C]lovastatin and [14C]simvastatin, were high. In contrast, that of the hydrophilic inhibitor, [14C]pravastatin, was low and not significantly different from that of [14C]sucrose, an extracellular space marker. Similarly, the in vitro BBB permeability coefficients of [14C]lovastatin and [1C]simvastatin were high, while that of [14C]-pravastatin was low. The in vivo and in vitro transcellular permeabilities obtained for HMG-CoA reductase inhibitors were comparable. This study shows that the BBB permeability correlates with the CNS side effects of the HMG-CoA reductase inhibitors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018975928974
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Transcellular Transport of Benzole Acid Across Caco-2 Cells by a pH-Dependent and Carrier-Mediated Transport Mechanism (1994)
    Springer
    Pharmaceutical research 11 (1994), S. 30-37 
    Details
    ISSN: 1573-904X
    Keywords: benzoic acid ; Caco-2 cell ; Monocarboxylic acid ; pH-dependent carrier-mediated transport ; pH-partition theory ; proton-coupled transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The pH-dependent transcellular transport of [14 C]benzoic acid across a Caco-2 cell monolayer is shown to be mediated by a monocarboxylic acid-specific carrier-mediated transport system, localized on the apical membrane. Evidence for the carrier-mediated transport of benzoic acid includes (a) the significant temperature and concentration dependence, (b) the metabolic energy dependence, (c) the inhibition by unlabeled benzoic acid and other monocarboxylic acids, (d) countertransport effects on the uptake of [14C]benzoic acid, and (e) effects of a proteinase (papain) and amino acid-modifying reagents. Furthermore, since carbonylcyanide p-trifluoromethoxyphenylhydrazone and nigericin significantly inhibited the transport of [14C] benzoic acid, the direct driving force for benzoic acid transport is suggested to be the inwardly directed proton gradient. From these results, together with previous observations using intestinal brush border membrane vesicles, the pH dependence of the transcellular transport of certain organic weak acids across Caco-2 cells is considered to result mainly from a proton gradient-dependent, carrier-mediated transport mechanism, rather than passive diffusion according to the pH-partition theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018933324914
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Characterization of the Transport Properties of a Quinolone Antibiotic, Fleroxacin, in Rat Choroid Plexus (1996)
    Springer
    Pharmaceutical research 13 (1996), S. 523-527 
    Details
    ISSN: 1573-904X
    Keywords: quinolone antibiotics ; cerebrospinal fluid ; blood-CSF barrier ; choroid plexus ; anion transport system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. It is reported that the cerebrospinal fluid (CSF) to plasma unbound concentration ratio of fleroxacin at steady-state is approximately 0.5 in experimental animals. These results can be accounted for by assuming the presence of an active transport system for the efflux of this compound across the choroid plexus. In the present study, the transport system for fleroxacin was characterized in isolated rat choroid plexus. Methods. Choroid plexus was isolated from the lateral ventricles of rats. The accumulation of [14C] fleroxacin or [3H] benzylpenicillin by the choroid plexus was examined by the centrifugal filtration method. Results. The accumulation of [14C] fleroxacin by the rat isolated choroid plexus was significantly inhibited by metabolic inhibitors (rotenone, 30 µM and carbonyl cyanide p-trifluorometh oxyphenylhydrazone (FCCP), 100 µM) and sulfhydryl reagent (p-chloromer-curibenzenesulfonic acid (PCMBS), 100 µM). This accumulation was composed of a saturable component (Vmax = 240 pmol·min−1·µl tissue−1, Km = 664 µM) and non-saturable one (P = 0.424 min−1·µl tissue−1). Accumulation of fleroxacin was competitively inhibited by benzylpenicillin and probenecid with Ki values of 29 µM and 51 µM, respectively. These values are comparable with the Km of benzylpenicillin transport and the Ki of probenecid for the benzylpenicillin transport at the choroid plexus, respectively. Furthermore, fleroxacin inhibited competitively the accumulation of [3H] benzylpenicillin with a Ki of 384 µM, a value comparable with the Km of [14C] fleroxacin transport. Conclusions. Fleroxacin and benzylpenicillin showed mutual competitive inhibition, suggesting that both are transported via a common transport system in the choroid plexus and are pumped out from CSF into the circulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016081618149
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Contribution of Parenchymal and Non-Parenchymal Liver Cells to the Clearance of Hepatocyte Growth Factor From the Circulation in Rats (1995)
    Springer
    Pharmaceutical research 12 (1995), S. 1737-1740 
    Details
    ISSN: 1573-904X
    Keywords: hepatocyte growth factor ; receptor-mediated endocytosis ; pharmacokinetics ; liver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. The distribution of 125I-hepatocyte growth factor (HGF) to either liver parenchymal cells (PC) or non-parenchymal cells (NPC) was investigated in rats. Methods. After injection of a trace amount of 125I-HGF, the distribution of radioactivity determined by microautoradiography closely resembled that of 125I-epidermal growth factor which distributes mainly to PC. Results. The uptake clearance of 125I-HGF estimated by determining the radioactivity of isolated liver cells was three times higher for PC than for NPC. This suggests that HGF distributes mainly to PC at relatively low doses. On the other hand, the uptake clearance by PC fell on coadministering an excess (80 µg/kg) of unlabeled HGF, while no change was observed for NPC, indicating that a saturable process for the hepatic handling of HGF exists only in PC where the HGF receptor is expressed. Conclusions. At such a dose the uptake clearance was comparable for both PC and NPC showing that HGF distributes to both cell types although NPC have few HGF receptors. Since the distribution to NPC was relatively non-specific and heparin-sensitive, it may be that heparin-like substances, which are believed to exist on PC and/ or the extracellular matrix, also exist on NPC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016273907749
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Kinetics of Quinolone Antibiotics in Rats: Efflux from Cerebrospinal Fluid to the Circulation (1996)
    Springer
    Pharmaceutical research 13 (1996), S. 1065-1068 
    Details
    ISSN: 1573-904X
    Keywords: quinolone antibiotics ; cerebrospinal fluid ; blood-CSF barrier ; choroid plexus ; blood-brain barrier
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. An active transport system, which pumps quinolone antimicrobial agents (quinolones) from cerebrospinal fluid (CSF) to systemic blood, exists at the choroid plexus, an epithelial tissue that forms the blood-CSF barrier (BCSFB). The present study was carried out to clarify the contribution of this transport system to the disposition of quinolones in the central nervous system. Methods. Six quinolones were administered intracerebroventricularly to rats and their elimination from the CSF was examined. The inhibitory effect of probenecid and quinolones on the efflux of fleroxacin from the CSF was also examined. Probenecid or two types of quinolone (AM-1155, pefloxacin) were co-administered intracerebroventricularly with fleroxacin. Results. The elimination clearance from the CSF for norfloxacin, AM-1155, fleroxacin, ofloxacin, sparfloxacin and pefloxacin was 14, 22, 21, 20, 47 and 35 µl/min/rat, respectively. An approximately 3.5-fold difference was thus observed between norfloxacin and sparfloxacin. These values were 4- to 14-fold larger than the [l4C]mannitol clearance. Furthermore, the elimination clearance of quinolones from the CSF was 7- to 60-fold larger than the active efflux clearance at the BCSFB estimated from our previous in vitro data. Co-administration of AM-1155, pefloxacin and probenecid did not inhibit the elimination of fleroxacin from the CSF. Conclusions. The active transport system at the BCSFB plays only a small part in the elimination of quinolones from the CSF. Passive diffusion via the BCSFB and diffusion across the ependymal surface into brain extracellular fluid, followed by efflux across the blood-brain barrier, may be the predominant pathway for quinolone elimination from the CSF.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016014909431
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Carrier-Mediated Transport of H1-Antagonist at the Blood–Brain Barrier: Mepyramine Uptake into Bovine Brain Capillary Endothelial Cells in Primary Monolayer Cultures (1994)
    Springer
    Pharmaceutical research 11 (1994), S. 975-978 
    Details
    ISSN: 1573-904X
    Keywords: mepyramine ; H1-antagonist ; blood-brain barrier transport ; carrier-mediated transport ; primary cultured brain capillary endothelial cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The transport mechanism of the H1antagonist mepyramine at the blood-brain barrier (BBB) was studied by using primary cultured monolayers of bovine brain capillary endothelial cells (BCEC). The initial uptake of [3H]mepyramine into the BCEC showed strong temperature and concentration dependency, indicating that it involves both saturable and nonsaturable processes. Transport at the luminal membrane may be the rate-limiting process in the transcellular transport, since the values of the uptake coefficient of [3H]mepyramine at the luminal membrane (609 µl/mg protein/min) and the transcellular permeability coefficient (488 µl/mg protein/min) are very similar. The initial uptake of [3H]mepyramine was not affected by metabolic inhibitors, but was stimulated by preloading with the drug. Mepyramine appears to be transported into the BCEC by a carrier-mediated transport system which does not require metabolic energy, probably via a facilitated diffusion mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018923017954
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Effect of Receptor Up-Regulation on Insulin Pharmacokinetics in Streptozotocin-Treated Diabetic Rats (1991)
    Springer
    Pharmaceutical research 8 (1991), S. 563-569 
    Details
    ISSN: 1573-904X
    Keywords: diabetic rats ; streptozotocin ; insulin pharmacokinetics ; hepatic clearance ; insulin receptor ; up-regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The present study investigated the mechanism by which the disposition of insulin is altered in streptozotocin (STZ)-treated diabetic rats as compared with 48-hr-fasted normal (control) rats. It was shown by an indocyanine green infusion method that the hepatic plasma flow rate (Q H) in diabetic rats (1.64 ml/min/g liver) is significantly higher than that in control rats (0.982 ml/min/g liver). The portal injection technique revealed that the unidirectional clearance (CLon), which represents the binding of A14-125 I-insulin to surface receptors in the liver, is significantly elevated in diabetic rats, suggesting an increase in the surface receptor number R T), i.e., up-regulation in the liver. In both control and diabetic rats, the total-body clearance (CLtot) and steady-state volume of distribution (Vd ss) of labeled insulin decreased significantly with a simultaneous injection of unlabeled insulin (8 U/kg), confirming that the disposition of insulin is affected largely by specific, saturable receptor-mediated processes. The CLtot and Vd ss increased significantly in diabetic rats, while nonspecific portions of these parameters were not changed. From the increases in CLtot (80%) and Q H (67%) in diabetic rats, a pharmacokinetic analysis has revealed a 40% increase in the hepatic intrinsic clearance (CLint sp) of A14-125 I-insulin via a specific mechanism in diabetic rats. In conclusion, we have provided in vivo evidence for a small increase in CLint sp of insulin in STZ-diabetic rats compared with control rats, which may be caused by an increase in the surface receptor number in the livers of diabetic rats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1015888203572
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    In Vivo Transport of a Dynorphin-like Analgesic Peptide, E-2078, Through the Blood–Brain Barrier: An Application of Brain Microdialysis (1991)
    Springer
    Pharmaceutical research 8 (1991), S. 815-820 
    Details
    ISSN: 1573-904X
    Keywords: brain microdialysis ; dynorphin-like analgesic peptide ; basic peptide ; blood–brain barrier (BBB) transport ; brain perfusion ; brain interstitial fluid ; blood–cerebrospinal fluid (BCSF) barrier ; absorptive-mediated endocytosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In vivo transport through the blood–brain barrier (BBB) has been demonstrated for a dynorphin-like analgesic peptide, CH3-[125I]Tyr-Gly-Gly-Phe-Leu-Arg-CH3Arg-D-Leu-NHC2H5 ([125I]E-2078). A remarkable time-dependent increase in the distribution volume of [125I]E-2078 in the brain parenchyma separated from blood vessels and capillaries was observed during a brain perfusion. The distribution volume of [125I]E-2078 in the brain parenchyma after 20 min of perfusion was 2.18 ± 0.09 µl/g brain (mean ± SE) and was significantly greater than the distribution volume of [3H]inulin (0.994 ± 0.138 (µl/g brain), providing in vivo evidence for the penetration of [125I]E-2078 into the brain parenchyma. Brain microdialysis was carried out to collect directly the brain interstitial fluid (ISF) during the brain perfusion of [125I]E-2078. No metabolite of [125I]E-2078 in the brain ISF was found by high-performance liquid chromatographic analysis of the brain dialysate. The concentrations of [125I]E-2078 and [14C]sucrose in the brain ISF were estimated based on an in vitro evaluation of dialysis clearance. The concentration ratio of [125I]E-2078 between the brain ISF and the brain perfusate was determined to be 2.92 × 10−l ± 0.50 × 10−l and was approximately 100 times higher than that of [14C]sucrose (2.71 × 10−3 ± 1.43 × 10−3), demonstrating transport of [125I]E-2078 through the BBB in vivo. On the other hand, no remarkable difference in the cerebrospinal fluid (CSF)-to-perfusate concentration ratios of [125I]E-2078 and [14C]sucrose was observed, indicating little contribution of the blood–CSF barrier (BCSF barrier) transport to the penetration of [125I]E-2078 into the brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1015882924470
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...