Library

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
    The intrinsic Cl–conductance of mouse kidney cortex brush-border membrane vesicles is not related to CFTR (1997)
    Springer
    Pflügers Archiv 434 (1997), S. 575-580 
    Details
    ISSN: 1432-2013
    Keywords: Key words Brush-border ; Membrane vesicle ; Cystic fibrosis transmembrane regulator (cftr) ; Alternate Cl ; conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstracts  Brush-border membrane vesicles (BBMV) were prepared from whole Balb/c mice kidneys by a Mg2+ precipitation technique. The presence of an intrinsic Cl–conductance co-expressed with Na+/glucose cotransport was inferred by the anion dependence of [14C]glucose uptake and overshoot with inward Na+-anion gradients. In Na+-equilibrated conditions, an inside-negative membrane potential difference (p.d.) produced by an inward Cl–gradient alone was capable of driving intravesicular [14C]glucose accumulation. The apparent anion conductance had a selectivity of Br– = I– = Cl– 〉  F–〉〉 gluconate, was inhibited by 0.5 mM 5-nitro-2- (3-phenylpropylamino)-benzoic acid (NPPB) but was unaffected by 0.5 mM 4,4′-diisothiocyanatostilbene 2,2′-disulphonate (DIDS). BBMV were isolated from mice in which the CFTR gene had been disrupted by a termination mutation (–/–) and compared with normal litter mates (+/+) and heterozygotes (–/+)[18]. [14C]Glucose uptake in NaCl media was significantly greater than glucose uptake in Na gluconate media for all three genotypes measured at 20 s: for homozygous –/– animals [14C]glucose uptake was increased by 2.80 ± 0.53 fold in Cl–media compared to gluconate media, n = 6; for wild-type +/+, by 2.16 ± 0.53 fold, n = 8; and for heterozygous +/– animals, by 2.17 ± 0.45 fold, n = 8. The observation of a Cl–-dependent component in BBMV isolated from homozygous –/– mutant animals shows that the chloride conductance in these vesicles cannot be due to cftr expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004240050438
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Characteristics of l-alanine transport in cardiac sarcolemmal vesicles and into isolated cardiac myocytes (1998)
    Springer
    Pflügers Archiv 436 (1998), S. 384-390 
    Details
    ISSN: 1432-2013
    Keywords: Key words l-Alanine ; l-Glutamate ; Transport ; Sarcolemma ; Myocardial protection ; Heart cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  During cardiac insults, heart cells synthesise and accumulate alanine as a part of the anaerobic energy production pathway. The transport of alanine presumably influences this pathway, making it important to characterise the l-alanine transporter in the heart. In this study, we have investigated the transport of l-alanine across the sarcolemma using a novel approach, namely utilisation of two preparations: cardiac sarcolemmal vesicles and cardiac myocytes. Both preparations were isolated from the heart of the same mammalian species. l-Alanine uptake in both preparations was sodium dependent. In the sarcolemmal vesicles, the sodium dependent component was electrogenic and saturated with an estimated Michaelis-Menten constant (K m) and maximal reaction velocity (V max) of 0.48±0.18 mM and 279.97±64.17 pmol/mg per min respectively at room temperature. In the isolated myocytes, l-alanine uptake was linear in sodium-containing media, with an estimated K m and V max of 9.65±0.76 mM and 169.81±13.22 pmol/µl per min respectively at 10°C for the sodium-dependent component. Inhibition of cotransport by a variety of substrates indicated that l-alanine uptake in the heart is mediated by an A- or ASC-like system. These characteristics of l-alanine transport suggest that under ischaemic conditions, l-alanine efflux will be activated, thus allowing for the continuous utilisation of other amino acids for energy production.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004240050647
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Co-expression of an anion conductance pathway with Na+-glucose cotransport in rat renal brush-border membrane vesicles (1993)
    Springer
    Pflügers Archiv 423 (1993), S. 406-410 
    Details
    ISSN: 1432-2013
    Keywords: Brush border ; Membrane vesicle ; Cl− conductance ; Cystic fibrosis transmembrane regulator ; Na-glucose cotransport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Brush-border membrane vesicles were prepared from superficial rat renal cortex by a Mg2+-precipitation technique. The initial (20 s) [14C]glucose uptake rate from solutions containing 100 mmol/l Na (salt) was found to be dependent upon the anion composition of the medium; in comparison to gluconate-containing medium (0.46±0.05 nmol/mg protein), Cl− accelerated the initial rate to 1.47±0.21 nmol/mg protein (n=4 preparations, ± SEM). This enhancement was reduced by 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB, 0.5 mmol/l), but was unaffected by 4,4′-diisothiocyanatostilbene 2,2′-disulphonate (DIDS, 0.5 mmol/l). When membrane vesicles were pre-equilibrated with 100 mmol/l K (salt) and 100 mmol/l mannitol and glucose uptake was measured from a solution containing 100 mmol/l Na gluconate and 100 mmol/l mannitol in the presence of 80 μmol/l valinomycin (to generate an outward K+ diffusion electrical p. d.), it was found that intravesicular KCl depressed the initial glucose uptake compared to K gluconate. NPPB (0.5 mmol/l) increased the initial glucose uptake with intravesicular KCl towards values seen in K gluconate vesicles. In conditions where the only driving force for glucose uptake was established by an inward anion gradient (Nao=Nai) it was found that inward Cl− gradients could drive uphill glucose transport and that this was sensitive to NPPB (0.5 mmol/l), but insensitive to DIDS. We conclude that a Cl− conductance co-exists with Na-cotransport in rat renal brush-border membrane vesicles prepared from superficial renal cortex and this may function to regulate the activity of electrogenic transport systems at this membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00374934
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The Rivermead Post Concussion Symptoms Questionnaire: a measure of symptoms commonly experienced after head injury and its reliability (1995)
    Springer
    Journal of neurology 242 (1995), S. 587-592 
    Details
    ISSN: 1432-1459
    Keywords: Head injury ; Post-concussion symptoms ; Rivermead Post Concussion Symptoms Questionnaire
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract After head injuries, particularly mild or moderate ones, a range of post-concussion symptoms (PCS) are often reported by patients. Such symptoms may significantly affect patients' psychosocial functioning. To date, no measure of the severity of PCS has been developed. This study presents the Rivermead Post Concussion Symptoms Questionnaire (RPQ) as such a measure, derived from published material, and investigates its reliability. The RPQ's reliability was investigated under two experimental conditions. Study 1 examined its test-retest reliability when used as a self-report questionnaire at 7–10 days after injury. Forty-one head-injured patients completed an RPQ at 7–10 days following their head injury and again approximately 24 h later. Study 2 examined the questionnaire's inter-rater reliability when used as a measure administered by two separate investigators. Forty-six head-injured patients had an RPQ administered by an investigator at 6 months after injury. A second investigator readministered the questionnaire approximately 7 days later. Spearman rank correlation coefficients were calculated for ratings on the total symptom scores, and for individual items. High reliability was found for the total PCS scores under both experimental conditions (R s = +0.91 in study 1 andR S = +0.87 in study 2). Good reliability was also found for individual PCS items generally, although with some variation between different symptoms. The results are discussed in relation to the major difficulties involved when looking for appropriate experimental criteria against which measures of PCS can be validated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00868811
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Total Synthesis of Oxazole- and Cyclopropane-Containing Epothilone A Analogues by the Olefin Metathesis Approach (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 1957-1970 
    Details
    ISSN: 0947-6539
    Keywords: epothilone ; oxazoles ; cyclopropanes ; metathesis ; total synthesis ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For structure-activity relationship studies, two series of epothilone A (1) analogues have been designed and synthesized, one containing an oxazole moiety instead of the thiazole heterocycle and the other containing a spirocyclopropane moiety in place of the gem-dimethyl group at position C-4 (4,4-ethano-epothilones). The olefin metathesis strategy in solution was utilized for the chemical synthesis of these compounds starting with key building blocks 7-9 for the oxazole series (compounds 2, 14-18, 21-26) and building blocks 8, 30, and 31 for the 4,4-ethano series (compounds 3,39-43, 46-51). The convergent strategy towards the designed epothilone A series involved a) an aldol condensation reaction, b) an esterification reaction, c) an olefin metathesis reaction catalyzed by [RuCl2(=CHPh)-(PCy3)2], and d) epoxidation of the macrocycle double bond.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970031211
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Total Synthesis of Oxazole- and Cyclopropane-Containing Epothilone B Analogues by the Macrolactonization Approach (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 1971-1986 
    Details
    ISSN: 0947-6539
    Keywords: epothilone ; oxazoles ; cyclopropanes ; total synthesis ; macrolactonizations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to probe structure-activity relationships in the epothilone area, two series of epothilone B analogues have been designed and synthesized. The first series containing an oxazole moiety in place of a thiazole on the side chain was constructed by utilizing key intermediates 7-9 or 10, 12, and 13 (Scheme 1), whereas the second series containing an ethano group instead of the gem-dimethyl group at position 4 was synthesized from fragments 42 and 43. A Yamaguchi-type macrolactonization reaction was used to construct the macrocycle from a secoacid, which was assembled, in both cases, by means of a) an aldol reaction, b) an Enders alkylation, and c) a Wittig-type reaction. This convergent strategy provided access to oxazole analogues 2,4,29-32 and 4,4-ethano derivatives 3,40,60-63 for biological studies.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970031212
    Library Location Call Number Volume/Issue/Year 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...