Kady, M M; Brimer, L; Furu, P
The molluscicidal principles of Ethulia conyzoides were identified as ethuliacoumarin A (1) and isoethuliacoumarin A (2). Ethuliacoumarin A possessed an LC90 between 19 and 23.5 ppm depending on the age of the snail against Biomphalaria glabrata, and between 12 and 15 ppm against Bulinus truncatu...
Garland, L G; Johansen, Torben
/l) and dicumarol (10 micronmol/l) did not reduce the adenosine 5'-triphosphate (ATP) content of mast cells in glucose-free medium. Higher concentrations of dicumarol (56-100 micronmol/l) markedly reduced the cellular ATP content. This reduction was reversed by glucose. 3 Papaverine was a more potent inhibitor...... of histamine release from mast cells incubated in glucose-free solution than in complete Tyrode solution (dose-ratio = 20). Like antimycin A (L MICRONMOL/L), PAPAVERINE (3 MICRONMOL/L) CAUSED A DEPLETION OF MAST CELL ATP that was greater in the absence (85%) than in the presence (25%) of extracellular glucose....... 4 These results suggest that dicumarol, like doxantrazole and theophylline, inhibits histamine release without affecting mast cell energy metabolism. In contrast, papaverine probably inhibits release by depleting ATP that is required for exocytosis. 5 Inhibition of histamine release by dibutyryl...
Lemley, C O; Wilson, M E
Progesterone is required for maintenance of pregnancy, and peripheral concentrations of progesterone are affected by both production and inactivation. Hepatic cytochrome P450 (EC 220.127.116.11) and aldo-keto reductase (EC 18.104.22.168-151) enzymes play a pivotal role in the first step of steroid inactivation, which involves the addition of hydroxyl groups to various sites of the cyclopentanoperhydrophenanthrene nucleus. The current objective was to discern the proportional involvement of hepatic progesterone inactivating enzymes on progesterone decay using specific enzyme inhibitors. Ticlopidine, diltiazem, curcumin, dicumarol, and naproxen were used because of their selective inhibition of cytochrome P450s, aldo-keto reductases, and glucuronosyltransferases. Liver biopsies were collected from 6 lactating Holstein dairy cows, and cells were dissociated using a nonperfusion technique. Confluent wells were preincubated for 4 h with enzyme inhibitor and then challenged with progesterone for 1 h. Cell viability was unaffected by inhibitor treatment and averaged 84±1%. In control wells, 50% of the progesterone had been inactivated after a 1-h challenge with 5 ng/mL of progesterone. Preincubation with curcumin, ticlopidine, or naproxen caused the greatest reduction in progesterone inactivation compared with controls and averaged 77, 39, or 37%, respectively. Hydroxylation of 4-nitrophenol to 4-nitrocatechol in intact cells was inhibited by approximately 65% after treatment with curcumin or ticlopidine. Glucuronidation of phenol red or 4-nitrocatechol in intact cells was inhibited by treatment with curcumin, dicumarol, or naproxen. In cytoplasmic preparations, aldo-keto reductase 1C activity was inhibited by curcumin, dicumarol, or naproxen treatment. Microsomal cytochrome P450 2C activity was inhibited by treatment with curcumin or ticlopidine, whereas cytochrome P450 3A activity was inhibited by treatment with curcumin or diltiazem. The contribution of cytochrome P450 2C and
Gómez-Outes, Antonio; Suárez-Gea, Ma Luisa; Calvo-Rojas, Gonzalo; Lecumberri, Ramón; Rocha, Eduardo; Pozo-Hernández, Carmen; Terleira-Fernández, Ana Isabel; Vargas-Castrillón, Emilio
The history of the traditional anticoagulants is marked by both perseverance and serendipity. The anticoagulant effect of heparin was discovered by McLean in 1915, while he was searching for a procoagulant in dog liver. Link identified dicumarol from spoiled sweet clover hay in 1939 as the causal agent of the sweet clover disease, a hemorrhagic disorder in cattle. Hirudin extracts from the medicinal leech were first used for parenteral anticoagulation in the clinic in 1909, but their use was limited due to adverse effects and difficulties in achieving highly purified extracts. Heparins and coumarins (i.e.: warfarin, phenprocoumon, acenocoumarol) have been the mainstay of anticoagulant therapy for more than 60 years. Over the past decades, the drug discovery paradigm has shifted toward rational design following a target-based approach, in which specific proteins, or "targets", are chosen on current understandings of pathophysiology, small molecules that inhibit the target's activity may be identified by high-throughput screening and, in selected cases, these new molecules can be developed further as drugs. Despite the application of rational design, serendipity has still played a significant role in some of the new discoveries. This review will focus on the discovery of the main anticoagulant drugs in current clinical use, like unfractionated heparin, low-molecular-weight heparins, fondaparinux, coumarins (i.e.: warfarin, acenocoumarol, phenprocoumon), parenteral direct thrombin inhibitors (DTIs) (i.e.: argatroban, recombinant hirudins, bivalirudin), oral DTIs (i.e.: dabigatran) and oral direct factor Xa inhibitors (i.e.: rivaroxaban, apixaban).
Hong, Yi-Guo; Guo, Jun; Sun, Guo-Ping
Previous studies have demonstrated that Shewanella decolorationis S12 can grow on the azo compound amaranth as the sole electron acceptor. Thus, to explore the mechanism of energy generation in this metabolism, membranous vesicles (MVs) were prepared and the mechanism of energy generation investigated. The membrane, which was fragmentized during preparation, automatically formed vesicles ranging from 37.5-112.5 nm in diameter under electron micrograph observation. Energy was conserved when coupling the azoreduction by the MVs of an azo compound or Fe(III) as the sole electron acceptor with H2, formate, or lactate as the electron donor. The amaranth reduction by the vesicles was found to be inhibited by specific respiratory inhibitors, including Cu(2+) ions, dicumarol, stigmatellin, and metyrapone, indicating that the azoreduction was indeed a respiration reaction. This finding was further confirmed by the fact that the ATP synthesis was repressed by the ATPase inhibitor N,N'-dicyclohexylcarbodiimide (DCCD). Therefore, this study offers solid evidence of a mechanism of microbial dissimilatory azoreduction on a subcell level.
Louise De Almeida
Full Text Available Cytochrome P450 monooxygenase 1A (CYP1A is induced by several planar toxic compounds, for example, polychlorinated biphenyls (PCBs and the induction of this protein is often measured in terms of CYP1A-mediated 7-ethoxyresorufin-O-deethylase (EROD activity. This study was aimed at developing this assay in the Cape hake species Merluccius capensis and Merluccius paradoxus (considered one stock. Microsomal fractions were obtained from frozen fish liver samples by differential centrifugation. Fluorimetric and spectrophotometric analysis of the EROD assay resulted in the spectrophotometric (at 572 nm detection method being selected, as this method resulted in a lower degree of variability and demonstrated higher reproducibility. The activity in the EROD assay was enhanced in the presence of NADPH, and the addition of dicumarol (phase II enzyme inhibitor to the reaction mixtures prevented the underestimation of this assay by the inhibition of DT-diaphorase. In summary, an EROD assay was established for use in Cape hake species.
Lindhagen, J; Haglund, M; Haglund, U; Holm, J; Scherstén, T
Twentyeight patients with ileofemoral venous thrombosis were treated surgically. Five of the patients had moderate degree of venous congestion, 18 patients had phlegmasia alba dolens and five patients had phlegmasia coerulea dolens. The mean age was 54 years, range 15-80 years, and 15 were men and 13 were women. In all cases the thrombosis was verified by phlebography. Thrombectomy was performed with a Fogarty venous thrombectomy catheter. Peroperative phlebography was used in most cases to guarantee complete extraction of thrombotic material. No operative pulmonary embolism or mortality was encountered. Postoperative continuous heparin infusion in the thrombectomized segment was used for the first week followed by dicumarol treatment. The patients were followed from 6 months to 4 years postoperatively. In two patients thrombectomy was not possible to perform. One of these patients developed a pronounced postthrombotic syndrome, the other developed venous congestion of more moderate degree. Excellent long-term time results were obtained in 82% of the patients and satisfactory in 14%. Thrombectomy is an efficient treatment of ileofemoral venous thrombosis.
Michael R. Roner
Full Text Available Organotin polyethers are easily synthesized employing interfacial polymerization systems involving the reaction of hydroxyl-containing Lewis bases and organotin halides. A wide variety of organotin-containing polymeric products have been synthesized including those derived from natural and synthetic polymers such as lignin, xylan, cellulose, dextran, and poly(vinyl alcohol. Others have been synthesized employing known drug diols such as dicumarol, DES, and dienestrol and a wide variety of synthetic diols. Included in these materials are the first water soluble organotin polymers. The organotin polyethers exhibit a wide range of biological activities. Some selectively inhibit a number of unwanted bacteria, including Staph. MRSA, and unwanted yeasts such as Candida albicans. Some also inhibit a variety of viruses including those responsible for herpes infections and smallpox. Others show good inhibition of a wide variety of cancer cell lines including cell lines associated with ovarian, colon, lung, prostrate, pancreatic and breast cancer. The synthesis, structural characterization, and biological characterization of these materials is described in this review.
Audi, Said H; Merker, Marilyn P; Krenz, Gary S; Ahuja, Taniya; Roerig, David L; Bongard, Robert D
The objective was to evaluate the pulmonary disposition of the ubiquinone homolog coenzyme Q(1) (CoQ(1)) on passage through lungs of normoxic (exposed to room air) and hyperoxic (exposed to 85% O(2) for 48 h) rats. CoQ(1) or its hydroquinone (CoQ(1)H(2)) was infused into the arterial inflow of isolated, perfused lungs, and the venous efflux rates of CoQ(1)H(2) and CoQ(1) were measured. CoQ(1)H(2) appeared in the venous effluent when CoQ(1) was infused, and CoQ(1) appeared when CoQ(1)H(2) was infused. In normoxic lungs, CoQ(1)H(2) efflux rates when CoQ(1) was infused decreased by 58 and 33% in the presence of rotenone (mitochondrial complex I inhibitor) and dicumarol [NAD(P)H-quinone oxidoreductase 1 (NQO1) inhibitor], respectively. Inhibitor studies also revealed that lung CoQ(1)H(2) oxidation was via mitochondrial complex III. In hyperoxic lungs, CoQ(1)H(2) efflux rates when CoQ(1) was infused decreased by 23% compared with normoxic lungs. Based on inhibitor effects and a kinetic model, the effect of hyperoxia could be attributed predominantly to 47% decrease in the capacity of complex I-mediated CoQ(1) reduction, with no change in the other redox processes. Complex I activity in lung homogenates was also lower for hyperoxic than for normoxic lungs. These studies reveal that lung complexes I and III and NQO1 play a dominant role in determining the vascular concentration and redox status of CoQ(1) during passage through the pulmonary circulation, and that exposure to hyperoxia decreases the overall capacity of the lung to reduce CoQ(1) to CoQ(1)H(2) due to a depression in complex I activity.
Hao, Fu-rong; Yan, Min-fen; Hu, Zhuo-han; Jin, Yi-zun
To provide the profiles of metabolism of mitomycin C (MMC) by human liver microsomes in vitro, MMC was incubated with human liver microsomes, then the supernatant component was isolated and detected by HPLC. Types of metabolic enzymes were estimated by the effect of NADPH or dicumarol (DIC) on metabolism of MMC. Standard, reaction, background control (microsomes was inactivated), negative control (no NADPH), and inhibitor group (adding DIC) were assigned, the results were analyzed by Graphpad Prism 4. 0 software. Reaction group compared with background control and negative control groups, 3 NADPH-dependent absorption peaks were additionally isolated by HPLC after MMC were incubated with human liver microsomes. Their retention times were 10. 0, 14. 0, 14. 8 min ( named as Ml, M2, M3) , respectively. Their formation was kept as Sigmoidal dose-response and their Km were 0. 52 (95% CI, 0. 40 - 0.67) mmol x L(-1), 0. 81 (95% CI, 0. 59 - 1. 10) mmol x L(-1), 0. 54 (95% CI, 0. 41 -0. 71) mmol x L(-1) , respectively. The data indicated that the three absorption peaks isolated by HPLC were metabolites of MMC. DIC can inhibit formation of M2, it' s dose-effect fitted to Sigmoidal curve and it' s IC50 was 59. 68 (95% CI, 40. 66 - 87. 61) micromol x L(-1) , which indicated DT-diaphorase could take part in the formation of M2. MMC can be metabolized by human liver microsomes in vitro, and at least three metabolites of MMC could be isolated by HPLC in the experiment, further study showed DT-diaphorase participated in the formation of M2.
Ma, Q; Wang, R; Yang, C S; Lu, A Y
A full-length cDNA clone, pKK-DTD4, complementary to rat liver cytosolic DT-diaphorase [NAD(P)H:quinone oxidoreductase (EC 22.214.171.124)] mRNA was expressed in Escherichia coli. The pKK-DTD4 cDNA was obtained by extending the 5'-end sequence of a rat liver DT-diaphorase cDNA clone, pDTD55, to include an ATG initiation codon and the NH2-terminal codons using polymerase chain reaction (PCR). Restriction sites for EcoRI and HindIII were incorporated at the 5'- and 3'-ends of the cDNA, respectively, by the PCR reaction. The resulting full-length cDNA was inserted into an expression vector, pKK2.7, at the EcoRI and HindIII restriction sites. E. coli strain AB1899 was transformed with the constructed expression plasmid, and DT-diaphorase was expressed under the control of the tac promotor. The expressed DT-diaphorase exhibited high activity of menadione reduction and was inhibited by dicumarol at a concentration of 10(-5)M. After purification by Cibacron Blue affinity chromatography, the expressed enzyme migrated as a single band on 12.5% sodium dodecyl sulfate-polyacrylamide gel with a molecular weight equivalent to that of the purified rat liver cytosolic DT-diaphorase. The purified expressed protein was recognized by polyclonal antibodies against rat liver DT-diaphorase on immunoblot analysis. It utilized either NADPH or NADH as electron donor at equal efficiency and displayed high activities in reduction of menadione, 1,4-benzoquinone, and 2,6-dichlorophenolindophenol which are typical substrates for DT-diaphorase. The expressed DT-diaphorase exhibited a typical flavoprotein spectrum with absorption peaks at 380 and 452 nm. Flavin content determination showed that it contained 2 mol of FAD per mole of the enzyme. Edman protein sequencing of the first 20 amino acid residues at the NH2 terminus of the expressed protein indicated that the expressed DT-diaphorase is not blocked at the NH2 terminus and has an alanine as the first amino acid. The remaining 19 amino acid
Ochmański, W; Barabasz, W
In buildings we can observe many different strains of bacteria, over 400 species of mould fungi, many strains of fungus causing the rotting of wood and wood like materials, many species of algae, aphids, and other types of growths and seed plants and also over 30 types of mites especially those seen in house dust. Buildings, especially their interiors have a very specific microclimate. Within it areas of so called ecological lows are formed in which conditions for settlement, growth and reproduction of these organisms take place. A building, which is a hazard to the health of its residents, is called a "sick building" from the term "sick building syndrome". The incidence and development of some types of mould fungus is associated with the production of very toxic metabolites which are called secondary metabolites i.e. mycotoxins. Long term human, especially in relation to children, contact with the species producing the most potent mycotoxins like aflatoxin--Apergillus flavus, ochratoxins--Aspergillus ochraceus, rubratoxins--Penicillium rubrum or strachybotrytoxins--Strachybotrys chartarum may even be the cause of death. Mould fungus or just mould is a saprophytic fungus derived from many different systemic groups (Mucor, Aspergillus, Penicillium, Fusarinum). Fungi can produce lethal mycotoxins such as: alternariol, aflatoxins, gliotoxins, ochratoxins, nivalenol, cytinine, dicumarol, rugulosine, trichoviridine and about 200 more which considering their mutagenicity are potentially dangerous to humans, animals, flora and microorganisms. Research which was begun by Prof. Julian Aleksandrowicz and Prof. Bolesław Smyk in 1970 and 1971 showed that the so called "leukaemia houses" of leukaemia victims had an abundance of toxinogenic fungus in them, particularly the most potent fungus which turned out to be Aspergillus flavus. Toxinogenic funguses are abundant in many living spaces and cellars in older and also in new housing. Mycotoxins have been shown to be very toxic