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Biomedical subjects

E Eich

Publications and source records attributed to E Eich.

At least 19 recordsLinked to original sources
PubMed1992

O-acylated lysergol and dihydrolysergol-I derivatives as competitive antagonists of 5-HT at 5-HT2 receptors of rat tail artery. Allosteric modulation instead of pseudoirreversible inhibition.

Twelve ergolines (O-acylated lysergol and dihydrolysergol-I derivatives) were synthesized to study their antagonism of 5-HT responses in comparison with methylsergide and LY 53857 [6-methyl-1-(1-methylethyl)-8 beta-ergoline carboxylic acid 2-hydroxy-1-methylpropyl-ester hydrogen maleate] in cylindrical segments of the isolated rat tail artery. With regard to (9.10-didehydro-6-methyl-8 beta-ergoline)methyl R,S-2-methylbutyrate, the most potent new ergoline derivative, we examined the phenomenon of insurmountable antagonism to 5-HT by methylsergide. O-Acylated lysergol and dihydrolysergol-I derivatives competitively antagonized 5-HT-induced contractions with calculated pA2 values of 7.30 +/- 0.42 for the weakest and 8.42 +/- 0.35 for the most potent ergoline derivative in this series. N1-isopropyl substitution did not generally enhance 5-HT2 receptor affinities but lowered affinities for alpha 1 adrenoceptors in rat aorta. Methysergide and LY 53857 were insurmountable antagonists of 5-HT in rat tail artery. Preincubation with (9.10-didehydro-6-methyl-8 beta-ergoline)methyl R,S-2-methylbutyrate (1 mumol/l) partially prevented the depression of 5-HT-induced contractions caused by methysergide (1-10 nmol/l). Methysergide (100 nmol/l) abolished the protective effect of (9.10-didehydro-6-methyl-8 beta-ergoline)methyl R,S-2-methylbutyrate. (9.10-Didehydro-6-methyl-8 beta-ergoline)methyl R,S-2-methylbutyrate (1 mumol/l), concomitantly incubated with methysergide (30 nmol/l), partially restored the maximum response to 5-HT that had been depressed by methysergide (30 nmol/l). Partial restoration could not be mimicked by washout of methysergide.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Clavine alkaloids and derivatives as mutagens detected in the Ames test.

Eight cytostatic clavines were investigated for mutagenicity in Salmonella typhimurium (reversion of the his-strains TA98, TA100, TA102 and TA1537), directly and in the presence of a mammalian xenobiotic metabolizing system, S9 (NADPH-fortified postmitochondrial fraction of liver homogenate from Aroclor 1254-treated rats). Four compounds (festuclavine, 17-bromofestuclavine, 1-allylelymoclavine and 1-methyllysergol methyl ether) were direct mutagens, whose activity was enhanced in the presence of S9. The other compounds (1-cyclopentylfestuclavine, 13-bromo-1-cyclopropylmethylfestuclavine, 6-cyano-1-propyl-6-norfestuclavine and 6-allyl-1-propyl-6-norfestuclavine) showed mutagenic effects only in the presence of S9, as previously observed with other clavines (agroclavine and its 1-propyl and 1-pentyl derivatives). Thus, all investigated clavines may be metabolized to mutagenic products by mammalian enzymes. Bacteriotoxic activities did not correlate with mutagenic activities. The bacteriotoxicity of several clavines was reduced in the presence of S9. The results are discussed with regard to the potential therapeutic use of clavine alkaloids as antimicrobial and antineoplastic agents.

Animals↗
PubMed1990

Inhibitory effects of novel festuclavine derivatives on nucleoside uptake and incorporation into DNA and RNA in human lymphoid leukemia Molt 4B cells.

Effects of festuclavine derivatives on nucleoside uptake by human lymphoid leukemia Molt 4B cells and on incorporation into TCA-insoluble materials in the cells were examined. The uptake and incorporation of uridine or thymidine were suppressed by festuclavine (EN01), 13-bromo-1-cyclopropylmethyl-festuclavine (EN02), 1-(4-chloro-benzenesulfonyl)festuclavine (EN03) and 1-cyclopentyl festuclavine (EN04) at 10-50 microM. Among these compounds, EN02 was most effective and at 50 microM it completely suppressed cellular uptake of the nucleosides and their incorporation into TCA-insoluble materials inhibiting the cellular proliferation. EN03 and EN04 moderately inhibited the transport and incorporation of the nucleosides in dose-dependent manners, while the mother compound EN01 had the least inhibitory effect. These findings indicated that alkylation at the indole nitrogen in combination with bromination at C-13 of the festuclavine molecule strengthened its inhibitory action on nucleoside uptake to a remarkable extent. The inhibition curves of nucleoside incorporation into TCA-insoluble materials showed quite similar dose-dependence to those of the inhibition curves for cellular nucleoside transport. These results suggest that the inhibitions of DNA and RNA syntheses by the festuclavine derivatives are due to the depressed transport of nucleosides into the leukemia cells.

Antibiotics, Antineoplastic↗
PubMed1990

Affect, pain, and autobiographical memory.

Twenty-five young female undergraduates were tested on two occasions: once when they were experiencing menstrual pain of at least moderate severity and once when they were pain free. On each occasion, Ss rated their current levels of pain and affect and retrieved real-life events from their personal past. At the end of the second occasion, Ss were reminded of all of the events they had retrieved on either occasion, and then rated the pleasantness of these events at the time of their original occurrence. Results revealed that the impact of pain on autobiographical memory was wholly mediated by its influence on mood. That is, pain impeded access to memories of pleasant personal experiences, whereas it promoted the retrieval of unpleasant events only if pain was accompanied by an increase in unpleasant affect. Discussion centers on the clinical and cognitive implications of the present results, and on prospects for future research.

Adaptation, Psychological↗
PubMed1987

Mutagenicity experiments on agroclavines, new natural antineoplastic compounds.

Agroclavine, an alkaloid produced by some species of fungi and dicotyledon plants, and its 1-alkylated derivatives are potentially useful as antineoplastic drugs, since they exert potent and selective cytostatic effects. In the present study, we have investigated agroclavine and its 1-propyl and 1-pentyl derivatives for mutagenicity. The genetic end point studied was the reversion of strains of Salmonella typhimurium (TA 100, TA 98, TA 1537) and Escherichia coli (WP2 uvrA), auxotrophic for histidine and tryptophan, respectively. The compounds were tested directly and in the presence of a mammalian xenobiotic-metabolizing system. In the direct test, agroclavine and the two alkylated derivatives examined exhibited substantial bacteriotoxicity but no mutagenicity. Addition of NADPH-fortified postmitochondrial supernatant fraction of rat liver homogenate led to a clear-cut decrease in bacteriotoxicity and to the formation of mutagenic products. Each compound was effective in all three strains of S. typhimurium used. In E. coli only spurious effects were seen. 1-Pentylagroclavine, the most hydrophobic compound in the series, was the strongest mutagen. Agroclavine, the least hydrophobic compound, was the weakest. The mutagenic potencies and efficacies of all these test compounds were much weaker than those of the positive controls, which were known mutagens and carcinogens. Moreover, the differential effect of metabolism by liver enzymes demonstrates that the toxicity and mutagenicity of agroclavine and its derivatives are caused by different chemical species. Hence, it may be possible to develop derivatives that are cytotoxic but not mutagenic.

Animals↗
PubMed1987

Cytosolic calcium and the action of vasopressin in toad urinary bladder.

The effects of experimental procedures believed to increase cytosolic calcium on basal and vasopressin-stimulated osmotic water flow and transepithelial sodium transport were examined in the toad urinary bladder. Exposure of isolated toad bladders to quinidine, calcium ionophores (A23187, X537A), or low-sodium or potassium-free serosal solutions resulted in a dose-dependent decrease in the hydrosmotic response to vasopressin or exogenous adenosine 3',5'-cyclic monophosphate (cAMP). The degree of inhibition of cAMP-induced water flow induced by low-sodium or potassium-free serosal bathing media varied, and in a similar manner, with the serosal calcium concentration. The effects of quinidine sulfate (2 X 10-4 M), X537A (2 X 10(-5) M), and low serosal sodium (20 mM), but not that of A23187 (10(-5) M), were readily reversible. Exposure to quinidine (4 X 10(-4) M), A23187 (10(-5) M), X537A (5 X 10(-6) M), or low serosal sodium (2 mM) also inhibited the basal short-circuit current (SCC). Vasopressin, 4-20 mU/ml, completely overcame the inhibition of the SCC induced by quinidine, A23187, or low serosal sodium, but a submaximal dose of hormone (4 mU/ml) failed to fully reverse the inhibitory effect of X537A, 5 X 10(-6) M. These results are consistent with the view that 1) a Na-Ca exchange process operates across the basolateral surface of the granular epithelial cells of the toad urinary bladder in vivo, and 2) the level of free calcium in the granular cell cytosol plays a modulatory role in the control of apical membrane water and sodium permeability by vasopressin, and in the regulation of the basal rate of transepithelial sodium transport.

Animals↗
PubMed1986

Effects of kinins on the isolated perfused rat kidney and evidence for the presence of renal B1 receptors.

The kinins, particularly lysyl-bradykinin (LBK), have a bimodal effect on the vasculature of isolated rat kidney. The vasorelaxant but not the vasoconstrictor effect of LBK seems to be mediated by prostaglandins. The vasoconstrictor action of LBK can be blocked by (L-Leu)8-des-Arg9-BK indicating that the rat kidney vasculature has B1 kinin-receptor which mediates the effects of kinins and/or their C-terminal metabolites.

Animals↗
PubMed1986

Biphasic and differential effects of the cytostatic agents avarone and avarol on DNA metabolism of human and murine T and B lymphocytes.

The two novel antimitotic and potent antileukemic agents avarone and avarol were determined to inhibit the [3H]-dThd incorporation rates of both murine spleen and human peripheral blood lymphocytes within the concentration range of 2-6 microM. The mitogens concanavalin A (ConA; for T lymphocytes), lipopolysaccharide (LPS; for murine B lymphocytes) and pokeweed mitogen (PWM; for human T and B lymphocytes) were used to stimulate DNA synthesis in the lymphocyte fractions. The ED50 concentrations, causing a 50% reduction of [3H]-dThd incorporation, were significantly lower in the experiments with avarone than in those with avarol. Moreover it was established that the DNA synthesis of ConA-activated lymphocytes was more sensitively inhibited by the compounds than that of LPS or PWM-activated cells, or non-activated cells. In addition it was elucidated that at low concentrations (1-2 microM) avarone and avarol caused a stimulation of dThd incorporation only in LPS or PWM-activated lymphocytes. Based on these results it is assumed that both antileukemic agents also affect differentially the different hematologic neoplasms.

Animals↗
PubMed1986

Clavines as antitumor agents, 3: Cytostatic activity and structure/activity relationships of 1-alkyl agroclavines and 6-alkyl 6-noragroclavines.

The cytostatic potential of twenty antibiotic agroclavines has been examined in the L5178y mouse lymphoma cell system. Twelve of these compounds are described for the first time. It is shown that the substituent at N-1 of agroclavine is very important whereas the substituent at N-6 is of less influence if it is not hydrogen. Incorporation studies in the presence of 1-propylagroclavine suggest that DNA synthesis in the lymphoma cells is inhibited. The effect on the corresponding [3H]thymidine incorporation in murine spleen lymphocytes is comparably low. Neither a significant change of mRNA efflux nor of DNA polymerase alpha and beta activities was caused. The mechanism of action seems to be a fundamentally new one for ergoline compounds as interactions with alpha-adrenoceptors, dopamine and 5-hydroxytryptamine receptors are not involved.

Animals↗
PubMed1985

Avarol, a cytostatically active compound from the marine sponge Dysidea avara.

A main metabolic product of the sponge Dysidea avara was isolated and purified and subsequently identified as avarol by applying a series of analytical techniques, e.g. [13C]NMR, [1H]NMR and i.r. spectroscopy. This sesquiterpenoid hydroquinone was found to possess strong cytostatic activity. Using the L5178y mouse lymphoma cell system in vitro (roller tube assays) avarol reduced cell growth to 50% at a concentration of 0.9 microM. Avarol treated cells did not show "unbalanced growth". Avarol interfered with mitotic processes, preventing telophase formation. Incorporation studies with precursors for DNA, RNA, protein and glycoprotein syntheses revealed increased incorporation rates in response to avarol treatment. From these results and further autoradiographical experiments it is suggested that inhibition of cell growth is due to changes of the intracellular pools and/or alterations of the permeability properties of the cell membrane for the precursors. Avarol diacetate caused the same cytostatic effect as avarol.

Animals↗
PubMed1985

Anion transport inhibitors: effects on water and sodium transport in the toad urinary bladder.

Acidification of the medium bathing the serosal surface of the toad urinary bladder results in impairment of the water permeability response to vasopressin. The magnitude of the hydrosmotic response to a maximal concentration of either vasopressin or the cyclic nucleotide analogue 8-(p-chlorophenylthio)-cyclic 3',5'-adenosine monophosphate (C1PhS-cAMP) was progressively reduced when serosal bath pH was decreased from 8.5 to 6.5. The disulfonic stilbenes SITS and DIDS and the diuretic furosemide, agents known to interfere with anion transport and with the regulation of intracellular pH in other tissues, inhibited the water flow response to vasopressin and C1PhS-cAMP in a pH-dependent manner when added to the serosal bathing medium. Inhibition of the hydrosmotic response to 10(-5) M C1PhS-cAMP was estimated to be half-maximal at 1.5 X 10(-4) M SITS, 2 X 10(-5) M DIDS, and 1 X 10(-5) M furosemide. The degree of inhibition induced by the anion transport inhibitors varied inversely with the concentration of exogenous cyclic nucleotide. SITS, DIDS, and furosemide had no effect on either basal or vasopressin-stimulated short-circuit current at serosal pH 8.5; all three agents inhibited basal short-circuit current at pH 7.1 but had no effect on the natriferic response to vasopressin. These results are consistent with the view that changes in intracellular hydrogen ion and/or anion concentration can selectively inhibit the increase in water permeability elicited by vasopressin at a step(s) distal to the generation of cAMP.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1985

Potent antileukemic activity of the novel cytostatic agent avarone and its analogues in vitro and in vivo.

Avarone and avarol are novel cytostatic agents which have potent antileukemic activity both in vitro and in vivo (mice). Cell culture experiments revealed that the cytostatic activity of these two compounds on L5178Y mouse lymphoma cells was 13- to 14-fold higher than that determined for HeLa cells and 40- to 43-fold higher than that for human melanoma cells. Nontumor cells (human fibroblasts and human gingival cells) were highly resistant against the two compounds. The inhibitory potency of avarone on L5178Y cells (50% inhibitory concentration, 0.62 microM) was significantly higher than the avarol activity (50% inhibitory concentration, 0.93 microM). Modification of the molecule at the quinone ring or the double bond in the terpenoid skeleton resulted in a significant loss of activity. In vivo studies with L5178Y cells in the ascites of mice confirmed the strong antileukemic effect determined in vitro. At doses of 10 mg/kg given i.p. once daily for 5 days to mice bearing approximately 10(8) leukemia cells, avarone was found to be curative in about 70% of the mice (20% for avarol). The optimal daily i.p. dose of avarone increased life span over controls by 146% when treatment was begun 1 day after tumor implantation and by 87% when treatment was delayed until day 8. Avarol, although active, was less effective. Based on the determined log10 kill values, avarone can be classified as a highly active and avarol as a markedly active cytostatic agent. The efficacy of the two compounds is also emphasized by the therapeutic index of 11.7 for avarone and of 4.5 for avarol. The two agents were determined not to be either direct mutagens or premutagens in the Ames test.

Animals↗
PubMed1985

Antimicrobial activity of clavines.

The antimicrobial activity of two clavine-type ergot alkaloids (agroclavine, festuclavine), and 16 derivatives against four human pathogenic bacteria and Candida albicans was determined. It is shown that all ergolines tested with one exception exhibit antibacterial properties against one to four bacteria species. The most active compounds are 6-allyl-6-norfestuclavine (minimal inhibitory concentration (MIC) 30 micrograms/ml against Staphylococcus aureus), 1-propyl-6-norfestuclavine (MIC 60 micrograms/ml against Escherichia coli), 6-cyano-6-norfestuclavine (MIC 250 micrograms/ml against Pseudomonas aeruginosa), and 1-methyl-agroclavine (MIC 200 micrograms/ml against Proteus vulgaris). 1-Allyl-6-norfestuclavine and 1-propyl-6-norfestuclavine showed a broad action spectrum: the growth of all four bacteria species and of Candida albicans was inhibited. The most effective antifungal compounds are 1-propyl-6-norfestuclavine and 6-cyano-6-norfestuclavine (MIC 250 micrograms/ml). Three alkaloids of different structure (codeine, emetine, quinine) are inactive up to 500 micrograms/ml against the bacteria species and C. albicans. The acute toxicity (mouse) is remarkably diminished by the modifications of the natural clavines.

Animals↗
PubMed1985

Anesthesia, amnesia, and the memory/awareness distinction.

Several studies have shown that surgical patients cannot consciously recall or recognize events to which they had been exposed during general anesthesia. Might evidence of memory for intraoperative events be revealed through the performance of a postoperative test that does not require remembering to be deliberate or intentional? Results of the present study, involving the recognition and spelling of semantically biased homophones, suggest a negative answer to this question and imply that intraoperative events cannot be remembered postoperatively, either with or without awareness.

Adult↗
PubMed1984

Clavines. New antibiotics with cytostatic activity.

The cytostatic potentials of ten ergolines were determined in the L5178y mouse lymphoma cell system; six of them belong to the clavines (agroclavine, 1-propyl-agroclavine, 1-propyl-festuclavine, 1-allyl-festuclavine, 6-cyano-6-nor-festuclavine and 1-hydroxymethyl-festuclavine) and four to the lysergic acid derivatives (methylergometrine, lysergic acid amide, isolysergic acid amide and lysergic acid diethylamide). It is shown that agroclavine (ED50: 3.9 microM), 1-propyl-agroclavine (3.5 microM), 1-propylfestuclavine (4.3 microM) and 1-allyl-festuclavine (4.3 microM) are potent cytostatic agents. Up to 2 X ED50 concentration the inhibitory effect was completely reversible. Incorporation studies suggested that the compounds inhibit DNA synthesis; this assumption was also supported by the findings which revealed that after incubation with these clavines, the cells showed slight 'unbalanced growth'. 6-Cyano-6-nor-festuclavine was less inhibitory (ED50 11.8 microM). 1-Hydroxymethyl-festuclavine and all lysergic acid derivatives tested were without any detectable activity.

Animals↗