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  • 1
    ISSN: 1432-0843
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Hexadecylphosphocholine (HPC) and octadecylphosphocholine (OPC) show very potent antitumor activity against autochthonous methylnitrosourea-induced mammary carcinomas in rats. The longer-chain and unsaturated homologue erucylphosphocholine (EPC) forms lamellar structures rather than micelles, but nonetheless exhibits antineoplastic activity. Methylnitrosourea was used in the present study to induce autochthonous mammary carcinomas in virgin Sprague-Dawley rats. At 6 and 11 days following oral therapy, the biodistribution of HPC, OPC and EPC was analyzed in the serum, tumor, liver, kidney, lung, small intestine, brain and spleen of rats by high-performance thin-layer chromatography. In contrast to the almost identical tumor response noted, the distribution of the three homologues differed markedly. The serum levels of 50 nmol/ml obtained for OPC and EPC were much lower than the value of 120 nmol/ml measured for HPC. Nevertheless, the quite different serum levels resulted in similar tumor concentrations of about 200 nmol/g for all three of the compounds. Whereas HPC preferably accumulated in the kidney (1 μmol/g), OPC was found at increased concentrations (400 nmol/g) in the spleen, kidney and lung. In spite of the high daily dose of 120 μmol/kg EPC as compared with 51 μmol/kg HPC or OPC, EPC concentrations (100–200 nmol/g) were low in most tissues. High EPC concentrations were found in the small intestine (628 nmol/g). Values of 170 nmol/g were found for HPC and OPC in the brain, whereas the EPC concentration was 120 nmol/g. Obviously, structural modifications in the alkyl chain strongly influence the distribution pattern of alkylphosphocholines in animals. Since EPC yielded the highest tissue-to-serum concentration ratio in tumor tissue (5.1) and the lowest levels in other organs, we conclude that EPC is the most promising candidate for drug development in cancer therapy.
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  • 2
    ISSN: 1432-0843
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution of the alkylphosphocholine hexadecylphosphocholine (He-PC) and the (alkyl)lysophospholipid 1-0-octadecyl-2-0-methyl-rac-glycero-3-phosphocholine (ET18-OCH3) was analyzed in rats. The compounds were given orally at a daily dose of 75 μmol/kg body weight. After 6, 11, and 18 days, three rats in each treatment group were killed and the drug concentration in various tissues and fluids was determined. With the exception of the kidney (He-PC) and brain (He-PC and ET18-OCH3), steady-state levels of the drugs could be achieved in all organs investigated and in serum. Maximal concentrations of He-PC were found in the kidney, adrenal glands, and spleen, whereas the highest concentrations of ET18-OCH3 were detected in the adrenal glands, spleen, and small intestine. The concentrations of He-PC exceeded those of ET18-OCH3 in most tissues by a factor of about 2–25. Since samples of urine and feces did not contain detectable amounts of the compounds, the absorption of both lipid analogues was assumed to be complete. The total amount of He-PC recovered after 6, 11, and 18 days was 15%, 12%, and 6%, respectively, and that of ET18-OCH3 was 1.3%, 0.8%, and 0.3%, respectively. This indicates that the bioavailability of He-PC and ET18-OCH3 is not controlled by differences in the uptake of the two drugs, but by differences in their metabolism. The results could explain the differing efficacy of these two compounds in their antitumor action in animal models.
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  • 3
    ISSN: 1434-4475
    Keywords: Keywords. Phosphonolipids ; synthesis of; Alkylphosphocholines; Phospholipase D; Michaelis-Becker reaction.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Wir beschreiben eine in sehr guten Ausbeuten verlaufende Reaktionsfolge zur Überführung langkettiger Alkohole in 3-(Trimethylammonium)propanphosphonate. Die Produkte sind Phospholipase D-stabile isostere Phosphonoanaloga der entsprechenden Alkylphosphocholine. Schlüsselschritt ist die Veresterung von 3-Chlorpropanphosphonsäure mit den entsprechenden langkettigen Alkoholen unter Verwendung von DCC/DMAP. Entschützung und verschiedene Acylierungen von 2-Hydroxy- und 2-Amino-Gruppen nach Einführung der Kopfgruppe werden beschrieben.
    Notes: Summary.  We describe a high yield reaction sequence for the conversion of long chain alcohols into 3-(trimethylammonio)propylphosphonates. The products are phospholipase D stable isosteric phosphono analogs of the respective alkylphosphocholines. The key step is the esterification of 3-chloropropylphosphonic acid with the respective long chain alcohols using DCC/DMAP. Deprotection and various acylations of 2-hydroxy and 2-amino groups following the introduction of the headgroup are described.
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  • 4
    ISSN: 1432-1335
    Keywords: Antineoplastic phospholipids ; U937 cells ; cell differentiation ; histone H10
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The proliferation of the human promonocytic leukemia cell line U937 is inhibited by several ether lipids, ether lipid analogues and by phorbol esters. An early effect of this retardation of cell growth is the induction of a basic chromosomal protein, histone H10. Northern blot analysis of H10 mRNA levels reveals an increase of the mRNA concentration within a few hours after addition of hexadecylphosphocholine and 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine. This early effect on the synthesis of a subtype of H1 proteins precedes the expression of several parameters of the monocytic differentiation of U937 cells.
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  • 5
    ISSN: 1432-1335
    Keywords: Anticancer drug ; Drug development ; High dose chemotherapy ; Multidrug resistance Gene therapy ; Inhibition of angiogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract General principles for anticancer drug development include traditional drug-screening methods in biological test systems. Today, testing of a drug in a panel of selected human tumor xenografts in mice is assumed to have the best predictive value for clinical efficacy. Chemical modification of well-known antitumor drugs from compound groups such as purine analogs, vinca alkaloids, antifolates and platinum analogs are carried out to increase anticancer activity, to reduce toxic side-effects and to improve pharmacokinetic properties of the drugs. In the last decade the enormous development in molecular techniques has led to the discovery of key proteins that are intimately involved in the regulation of cancer growth control. Cell growth inhibitors could be developed by structure-based drug design, creating small organic molecules (“peptide mimetics”) to target crucial enzymes, oncogenes or oncogene products, tumor-suppressor genes and their products as well as growth factors and their corresponding receptors. Drugs representing new leading structures, like alkylphosphocholines, topoisomerase I inhibitors, taxoids and suramin, have already entered the clinic. Novel therapeutic approaches may provide substantial progress in cancer treatment in the very near future. Examples are the concept of high-dose chemotherapy with hematopoietic stem cell support, the various strategies of gene therapy, the modulation of multi-drug resistance of cancer cells, and strategies to inhibit tumor angiogenesis.
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  • 6
    ISSN: 1573-0646
    Keywords: aminoglutethimide ; blood brain barrier ; cerebrospinal fluid concentration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract The uptake of 14C-labeled aminoglutethimide into the brain was investigated in the rat after intracarotid injection according to the method of Oldendorf, as well as in cisternal cerebrospinal fluid obtained by suboccipital puncture after i.v. injection of the drug. The brain uptake index of aminoglutethimide after intracarotid injection was 30.7 + 2.4%. Cerebrospinal fluid/blood quotients after i.v. drug injection were 0.53 at 10 min and 0.26 at 60 min. The results of both methods clearly show that aminoglutethimide easily penetrates the blood brain barrier.
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  • 7
    ISSN: 0009-2940
    Keywords: 1,2-Oxazines, lithiated ; Deprotonation ; Alkylation ; Deuteration ; Regioselectivity ; Calculations, MNDO ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 5,6-Dihydro-5-methylene-4H-1,2-oxazine 1 is smoothly converted by n-butyllithium into 1-Li which reacts with electrophiles such as D2O, carbonyl compounds, dimethyl sulfide, or an azo diester to give the γ-adducts 4a-4f. On the other hand, alkylation of 1-Li occurs exclusively at C-4 of the heterocycle and provides the α-adducts 3g and 3h. These reactions require the activation of 1-Li by tetramethylethylenediamine. Treatment with allyl bromide and methyl acrylate affords mixtures of regioisomers 3 and 4. 1,2-Oxazine 5 with a conjugated C = C bond is less acidic than 1 but is also converted into 1-Li, whilst compound 6, lacking the 6-methoxy group, is not deprotonated under standard conditions. The dianion of 1,2-oxazine 7 is generated by employing an excess of n-butyllithium. This dianion displays a similar regiochemical behavior as 1-Li. Deuterium is exclusively incorporated into the γ-position to give product 8, while methylation occurs at C-4 to produce 9. 1,2-Oxazine 3g with an additional 4-methyl group can also be metalated and affords γ-adducts 10 and 11 upon reaction with D2O or acetone. Treatment with methyl iodide gives a 3:1 mixture of regioisomers 12 and 13. Deuteration of 1,2-oxazines 14 and 16 bearing a 3-CF3 or 3-CO2Et substituent requires more severe deprotonation conditions to provide the γ-adducts 15 and 17 in moderate yields. MNDO calculations of neutral 1,2-oxazines, the corresponding carbanions, and the lithium compounds allow an insight into the structure and charge distribution of these species, and also an estimation of the relative acidities. The regioselectivity of reactions of 1-Li is discussed on the basis of these semiempirical calculations and comparison with related ambident nucleophiles.
    Additional Material: 1 Ill.
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