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
Filter
  • Membrane vesicle  (2)
  • oxazoles  (2)
  • Key words: Cerebral injury — Hypothermia — Cardiopulmonary bypass  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Experimental Evidence of Cerebral Injury from Profound Hypothermia During Cardiopulmonary Bypass (1998)
    Springer
    Pediatric cardiology 19 (1998), S. 398-403 
    Details
    ISSN: 1432-1971
    Keywords: Key words: Cerebral injury — Hypothermia — Cardiopulmonary bypass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Choreoathetosis, seizures, and impaired mental development continue to occur in children undergoing cardiopulmonary bypass (CPB) and profound hypothermia with or without circulatory arrest. Although there is some evidence that the hypothermia itself may be causing these neurologic problems, skepticism remains because of lack of evidence from experimental studies simulating the clinical setting. In this experimental study, we examined the effect of profound and moderate hypothermia on the brain while maintaining normal flow rates during CPB. Ten adult mongrel dogs equally divided into two groups were anesthetized and subjected to CPB and varying levels of hypothermia (group 1, ≤15°C; group 2, ≤32°C). Both groups were kept at the desired temperature for 1 hour prior to rewarming and discontinuation of CPB. The dogs were euthanized 4–6 weeks later and neuropathologic studies were performed. The mean CPB flow rates during cooling and at the desired rectal temperature were comparable in both groups: group 1, 108 ± 10 ml/kg/min versus 106 ± 7 ml/kg/min in group 2 (p= NS) and 95 ± 12 ml/kg/min in group 1 versus 101 ± 5 ml/kg/min in group 2 (p= NS). Because of the difference in temperature between the two groups, the mean cooling time (onset of CPB to desired rectal temperature) was longer in group 1 (70 ± 14 minutes) than in group 2 (28 ± 11 minutes, p= 0.007). Hence, the total mean CPB time was also longer in group 1 (198 ± 25 minutes) than in group 2 (143 ± 13 minutes, p= 0.002). The lowest mean blood and rectal temperature achieved in group 1 were 11 ± .9°C and 12 ± 1°C versus 29 ± .4°C (p 〈 0.001) and 30 ± .6°C (p= 0.001), respectively, in group 2 (p= 0.001). Neuronal loss and degeneration was noted in all dogs in group 1 ranging from 2 to 8 cells per 1000 cells counted compared to none in group 2 (p= 0.05). These lesions occurred in both the basal ganglia and the cortex, although they were more marked in the caudate when compared to the cortex and cerebellum. Both in the cortex and in the caudate, neuronal loss was more marked around the capillaries. We conclude that the use of profound hypothermia of ≤15°C and maintenance of normal flow rates during cooling at this temperature for 1 hour produces neuronal loss and degeneration in the brain. These lesions being more marked around capillaries points to the vulnerability of the neurons, probably because of their high lipid content to injury from the cold perfusate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002469900335
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    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
  • 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
    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
  • 5
    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...