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At least 361 records · Page 20Linked to original sources
PubMed2005

Enzymatic properties of a member (AKR1C19) of the aldo-keto reductase family.

A member (AKR1C19) of the aldo-keto reductase (AKR) superfamily, found by mouse genomic analysis, was shown to be highly expressed in the liver and gastrointestinal tract, but its function remains unknown. In this study, the recombinant AKR1C19 was expressed and purified to homogeneity. The enzyme was a 36-kDa monomer, and reduced alpha-dicarbonyl compounds such as camphorquinone and isatin using both NADH and NADPH as the coenzymes. Although apparent kinetic constants for the two coenzymes were similar, the NADPH-linked activity was potently inhibited by submillimolar concentrations of NAD+, but the inhibition of the NADH-linked activity was not significant, suggesting that the enzyme exhibits the NADH-linked reductase activity in vivo. AKR1C19 slowly oxidized 3-hydroxyhexobarbital, S-indan-1-ol and cis-benzene dihydrodiol, but was inactive towards steroids, prostaglandins, monosaccharides, and other xenobiotic alcohols. In addition, the enzyme was inhibited only by dicumarol, lithocholic acid and genistein of various compounds tested. Thus, AKR1C19 possesses properties distinct from other members of the AKR superfamily, and may function as a reductase for endogenous isatin and xenobiotic alpha-dicarbonyl compounds in the liver and gastrointestinal tract.

Alcohol Oxidoreductases↗
PubMed2006

The dopamine D3 receptor is part of a homeostatic pathway regulating ethanol consumption.

We recently identified a homeostatic pathway that inhibits ethanol intake. This protective pathway consists of the scaffolding protein RACK1 and brain-derived neurotrophic factor (BDNF). RACK1 translocates to the nucleus after exposure of neurons to ethanol and increases expression of BDNF (McGough et al., 2004). We also found that increasing the levels of BDNF via systemic administration of RACK1 expressed as a Tat-fusion protein (Tat-RACK1) reduces ethanol consumption, whereas reduction of BDNF levels augments this behavior (McGough et al., 2004). Based on these results, we hypothesized that activation of the BDNF receptor TrkB is necessary for the effects of BDNF on ethanol intake and that gene products downstream of BDNF negatively regulate ethanol consumption. Here, we show that inhibition of the BDNF receptor TrkB increases voluntary ethanol consumption in wild-type mice but not in mice lacking one copy of the BDNF gene (BDNF(+/-)). We also find that increases in the levels of BDNF, mediated by ethanol or RACK1, lead to increased dorsal striatal levels of the dopamine D3 receptor (D3R), a gene downstream of BDNF, via activation of the TrkB receptor. Finally, we show that the Tat-RACK1-mediated reduction of ethanol consumption is attenuated by coinjection with either the Trk inhibitor K252a or the dopamine D3R-prefering antagonist U-99194A [5, 6-dimethoxy-2-(di-n-propylamino)indan], suggesting that activation of the BDNF pathway via RACK1 leads to increased expression of the dopamine D3R, which in turn mediates the attenuation of ethanol consumption.

Alcohol Drinking↗
PubMed2005

The genetic basis of resistance to anticoagulants in rodents.

Anticoagulant compounds, i.e., derivatives of either 4-hydroxycoumarin (e.g., warfarin, bromadiolone) or indane-1,3-dione (e.g., diphacinone, chlorophacinone), have been in worldwide use as rodenticides for >50 years. These compounds inhibit blood coagulation by repression of the vitamin K reductase reaction (VKOR). Anticoagulant-resistant rodent populations have been reported from many countries and pose a considerable problem for pest control. Resistance is transmitted as an autosomal dominant trait although, until recently, the basic genetic mutation was unknown. Here, we report on the identification of eight different mutations in the VKORC1 gene in resistant laboratory strains of brown rats and house mice and in wild-caught brown rats from various locations in Europe with five of these mutations affecting only two amino acids (Tyr139Cys, Tyr139Ser, Tyr139Phe and Leu128Gln, Leu128Ser). By recombinant expression of VKORC1 constructs in HEK293 cells we demonstrate that mutations at Tyr139 confer resistance to warfarin at variable degrees while the other mutations, in addition, dramatically reduce VKOR activity. Our data strongly argue for at least seven independent mutation events in brown rats and two in mice. They suggest that mutations in VKORC1 are the genetic basis of anticoagulant resistance in wild populations of rodents, although the mutations alone do not explain all aspects of resistance that have been reported. We hypothesize that these mutations, apart from generating structural changes in the VKORC1 protein, may induce compensatory mechanisms to maintain blood clotting. Our findings provide the basis for a DNA-based field monitoring of anticoagulant resistance in rodents.

Amino Acid Motifs↗
PubMed2004

occupational exposure to aromatic hydrocarbons at a coke plant: Part II. Exposure assessment of volatile organic compounds.

The objective of the study is to assess the external and internal exposures to aromatic hydrocarbons in the tar and oil naphthalene distillation processes at a coke plant. 69 workers engaged as operators in tar and oil naphthalene distillation processes and 25 non-exposed subjects were examined. Personal analyses of the benzene, toluene, xylene isomers, ethylbenzene, naphthalene, indan, indene and acenaphthene in the breathing zone air allowed us to determine the time weighted average exposure levels to the aromatic hydrocarbons listed above. The internal exposure was investigated by measurement of the urinary excretion of naphthols, 2-methylphenol and dimethylphenol isomers by means of gas chromatography with a flame ionization detection (GC/FID). Urine metabolites were extracted after enzymatic hydrolysis by solid-phase extraction with styrene-divinylbenzene resin. The time-weighted average concentrations of the hydrocarbons detected in the breathing zone air shows that the exposure levels of the workers are relatively low in comparison to the exposure limits. Statistically significant differences between average concentrations of aromatic hydrocarbons (benzene, toluene, xylene isomers) determined at the workplaces in the tar distillation department have been found. Concentrations of the naphthalene and acenaphthene detected in workers from the oil distillation department are higher that those from the tar distillation department. Concentrations of naphthols, 2-methoxyphenol and dimethylphenol isomers in the urine of occupationally exposed workers were significantly higher than those of non-exposed subjects. Concentrations of the 2-methoxyphenol and dimethylphenol isomers in urine were significantly higher for the tar distillation workers, whereas concentrations of naphthols were higher for the oil naphthalene distillation workers. Operators at the tar and naphthalene oil distillation processes are simultaneously exposed to a mixture of different hydrocarbons, mainly benzene and naphthalene homologues.

Acenaphthenes↗
PubMed2001

Molecular mimetics of Neisseria meningitidis serogroup B polysaccharide.

Strains of Neisseria meningitidis serogroup B (NmB) are an important cause of meningitis and sepsis. Efforts to develop a NmB vaccine have been hampered by poor immunogenicity of the polysaccharide capsule, which cross-reacts with host polysialic acid, and the danger of eliciting autoantibodies. To investigate the potential of molecular mimetics to circumvent these problems, we prepared murine monoclonal antibodies (mAbs) against the N-propionyl derivative (N-Pr) of NmB polysaccharide. Several mAbs were found that reacted with capsular polysaccharide epitopes, which were distinct from host polysialic acid. These mAbs also passively conferred protection against experimental bacteremia. We used these mAbs to screen novel independently folding peptide phage display libraries, and pools of combinatorial small molecules, each consisting of approximately 30 to approximately 700 small molecules of diverse composition. To date, several mimetic candidates have been identified. One is a peptide selected from a library of independently folding alphabeta peptides, and others are peptoid dimers or trimers selected from the small molecule pools. The peptoids contain an indan-type of ring system, and some of them also contain a large hydrophobic group such as oleyl amine or dehydroabietyl amine, and a positively charged group at the amino-terminus. Both the alphabeta peptide from the phage library, and the peptoids from the small molecule pools, inhibit binding of the mAbs to N-Pr NmB polysaccharide. Future studies will focus on the structure/activity relationship of these mimetics, and the development of immunogens that may be capable of eliciting anticapsular antibody without autoantibody activity.

Amino Acid Sequence↗
PubMed1999

Pharmacokinetics and safety of Z-321, a novel specific orally active prolyl endopeptidase inhibitor, in healthy male volunteers.

This study investigates the pharmacokinetics and safety profile of Z-321, (4R)-3-(indan-2-ylacetyl)-4-(1-pyrrolidinyl-carbonyl)-1,3-thiazoli dine, a novel specific orally active prolyl endopeptidase (PEP) inhibitor. Following a preliminary safety evaluation wherein 2 subjects received 3.75 and 15 mg doses and 2 other subjects received 7.5 and 30 mg doses, 16 subjects were assigned to two groups of 8 subjects each. In each group, 6 subjects were to receive active treatment, and 1 or 2 subjects were to receive placebo treatment. One group received 60 mg under fasted and fed conditions. A separate group of 8 subjects received 60 mg of Z-321 or a placebo in a bid regimen for 6 days and the morning dose on day 7. The concentrations of Z-321 and its main metabolites--R- and S-sulfoxide; RR-, SS-, and RS-indanol; and indanolsulfoxides in plasma and urine--were determined by the HPLC method. In the multiple-dose study, the cholinesterase activity was gradually increased and reached above the normal range on day 8 in 3 of 6 subjects given Z-321 and gradually returned to the normal range after completion of dosing. The elevation of plasma cholinesterase activity was considered to be an action of Z-321, but this remains to be verified. In a single-dose study at a dose of 30 mg, headache and vomiting were observed in 1 of 6 subjects. In the multiple-dose study, slight skin itching and eczema in 3 and 2 of 6 subjects, respectively, and headache in 2 of 6 subjects were observed, but all symptoms were not severe. There were no other abnormal findings in objective signs and laboratory findings, including blood pressure, heart rate, electrocardiogram, body temperature, hematology, blood chemistry, and urinalysis. The Cmax of Z-321 at 30, 60, and 120 mg in the fasting state were 63.7 +/- 23.9, 102.0 +/- 43.1, and 543.3 +/- 437.0 ng/ml (mean +/- SD), respectively, at 0.9 hours after administration, and the t1/2 was about 1.8 hours. There were no dramatic changes in the pharmacokinetics of Z-321 in the presence of food. In the multiple-dose study, there was no drug accumulation trend in plasma. These results indicate that Z-321 has acceptable pharmacodynamic and pharmacokinetics profiles for clinical use without any serious adverse events, as verified in healthy young male volunteers.

Adult↗
PubMed1999

Hexasupersilyloctaindane (tBu(3)Si)(6)In(8)- A Compound with a Novel In(8) Cluster Framework.

A doubly capped In(6) octahedron characterizes the structure of the dark green octaindane (tBu(3)Si)(6)In(8) (see picture), which is obtained from (C(5)Me(5))In and tBu(3)SiNa in pentane at -78 degrees C. In1/In1' are the capping atoms, and In2/In2' form the apexes of the stretched In(6) octahedron. Thus, in agreement with the results of ab initio calculations, the compound can be classified as a hypoprecloso-indane.

Journal Article↗
PubMed2000

[Liquid-solid adsorption separation and gas chromatography/mass spectrometry analysis of recycle alkanes in the production of alkyl benzenes].

A method for qualitative and quantitative analysis of recycle alkanes in the production of alkyl benzenes is proposed in this paper. The mixture was separated into saturated hydrocarbons (alkanes and cyclanes) and aromatics by means of adsorption chromatography with silica gel of 100 mesh-200 mesh as stationary phase and n-pentane and dichloromethane as eluents. Results were obtained by analysing these two fractions separately. A total of 21 different kinds of n-, iso-, cyclo and a few light aromatic hydrocarbons were identified in the saturated hydrocarbons which were 97.3% of the mixture, while the rest 2.4% aromatic hydrocarbons included 15 different kinds of indanes, naphthanes and diphenylanes, the majority of which were products of dehydrogenation and alkylation, and the minor part was from original alkanes. By-products can be truely revealed by the qualitative analysis, which can be used to improve the process conditions. Analysis showed that after adsorption separation by silica gel, the low-content aromatic hydrocarbons was concentrated, and thus the analysis accuracy and sensitivity were improved. Preseparation avoided the problems which would appear if the samples were directly analysed by gas chromatography or gas chromatography/mass spectrometry.

English Abstract↗
PubMed1976

Antiinflammatory activity of two phenylindandione derivatives.

2-5-Dibromo-2-(beta-naphtyl)indan-1,3-dione (43/63) and 4-bromo-2-phenylindan-1,3-dione (43/13) are two interesting members of a series of "indandione" derivatives which possess an antiinflammatory activity (in the following tests: carrageenin induced rat hind paw edema, cotton pellets granuloma and chronic adjuvant arthritis). The two drugs are devoided of anticoagulant activity and their antiinflammatory effect is not adrenalmediated.

Animals↗
PubMedDate not supplied

Development of rational in vitro models for drug resistance in breast cancer and modulation of MDR by selected compounds.

BACKGROUND: [corrected] The effectiveness of chemotherapy is limited by the emergence of multidrug resistance (MDR). MDR is caused by the activity of various ATP binding cassette (ABC) transporters that pump anticancer drugs out of the cells in an ATP-dependent manner. Additionally some other cellular mechanisms of MDR have been reported. The purpose of this study was to investigate mechanisms of MDR in drug resistant MCF-7 cell lines and to modulate P-glycoprotein (P-gp) and MRP1-based MDR. MATERIALS AND METHODS: Paclitaxel (MCF-7/Pac), docetaxel (MCF-7/Doc), doxorubicin (MCF-7/Dox) and vincristine (MCF-7/Vinc) resistant sublines were developed from the parent MCF-7 cell line (MCF-7/S) by stepwise selection in dose increments over two years. Flow cytometry, MTT cytotoxicity assay, RT-PCR, caspase-3 activity assay and checkerboard combination assay were performed to investigate the degree of resistance developed in sublines and to reverse drug resistance phenotype. RESULTS: The flow cytometry histograms of drug accumulation assays demonstrated that the drug-resistant cell lines are P-gp and MRPI positive. RT-PCR results showed that the resistant sublines express both MDR1 and MRP1 genes. Resistance indices of each subline to each anticancer drug were determined using the MTT cytotoxicity assay and it was found that all the sublines were resistant to their respective agents. Caspase-3 activities of the cell lines were also determined. Caspase-3 activity is an important indicator of apoptosis in the cell. The reversal of MDR was attempted by two cinnamylidene ketone and two organosilicon compounds. The results indicated that these compounds modulated P-gp effectively, but they were not very effective at reversing MRP1 activity in the MCF-7 sublines. Four selective anticancer drugs (paclitaxel, docetaxel, doxorubicin and vincristine) and four synthetic MDR modulators [2-(2-methoxycinnamylidene) indan-1-one (cinnamylidene-1), 2-(2- methoxycinnamylidene)-3, 4-dihydro-2H-naphthelen-1-one) (cinnamylidene-2), ALIS 409 and ALIS 421] were applied to the sublines in combination. The fractional inhibitory indices illustrated that combined applications of cinnamylidene ketones and organosilicon compounds with paclitaxel, docetaxel or vincristine exerted significant antiproliferative effects on the resistant sublines. CONCLUSION: This report demonstrates the development of rational models for drug resistance MCF-7 cell lines and reversal of acquired drug resistance.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1991

Structural function of residue-209 in coumarin 7-hydroxylase (P450coh). Enzyme-kinetic studies and site-directed mutagenesis.

Residue-209 plays a critical role in determining the substrate and product specificity of cytochrome P450coh. In order to investigate further the structural function of residue-209 in coumarin 7-hydroxylase reaction, we measured the enzyme-kinetic properties of wild-type P450coh and its mutants in which residue-209 was substituted with various amino acids. In general, the Km and Vmax values for coumarin increased as the size of residue-209 became smaller and Vmax values decreased. The size of residue-209, therefore, was a principle factor determining Km, Kd, and Vmax values of P450coh. Although the polarity and charge also increased the Km value consistently, they altered Vmax and Kd values in an irregular manner. The substitution of serine for residue-209 increased the Vmax, while the substitution of lysine decreased it. Coumarin 7-hydroxylase activity was inhibited weakly by indan, but competitively and strongly by 2-coumaranone. Moreover, Ki values for the inhibitor were similar to Km values of the corresponding, mutated P450s. The results indicate, therefore, that residue-209 is localized in a proposed substrate-binding sequence 1 which binds to the 2-keto group of coumarin and directs its 7-position toward the sixth ligand of heme. Consequently, the identity of residue-209 determines not only the binding of coumarin in P450coh, but also the other reaction step(s) of coumarin 7-hydroxylation.

Amino Acids↗
PubMed1990

The metabolic functions and mechanism of action of vitamin K.

Vitamin K functions in animal cells as the cofactor of the enzyme vitamin K-dependent carboxylase which catalyzes the post-translational formation of gamma-carboxyglutamyl (Gla) residues in specific vitamin K-dependent proteins. These proteins include four blood coagulation factors (prothrombin and Factors VII, IX and X), other plasma proteins (protein C, protein S and protein Z), two proteins from bone (osteocalcin or bone Gla-protein and matrix Gla-protein), and other proteins from lung, kidney, spleen, testis, placenta and other tissues. In the proteins involved in blood coagulation the Gla residues are mandatory for the activation of the inactive proenzymes; this process occurs on phospholipid surfaces to which the proenzymes are bound via Gla residues and calcium ions. The energy needed in the carboxylation reaction is obtained from the oxidation of vitamin K hydroquinone to 2,3-epoxide of the vitamin. Specific enzymes, vitamin K epoxide reductase and vitamin K quinone reductases, catalyze consecutive reactions in which the vitamin K hydroquinone is regenerated, thus allowing continued use of the vitamin K molecule for the carboxylations. The oral anticoagulants, derivatives of 4-hydroxycoumarin and indan-1,3-dione, used as therapeutic agents in thromboembolic disease, are antagonists to vitamin K preventing the catalytic use of vitamin K in the carboxylations by irreversibly inhibiting vitamin K epoxide reductase.

Animals↗
PubMedDate not supplied

[Complications of anticoagulant treatment. Report of 98 accidents and incidents (author's transl)].

According to an estimation on 1 587 patients under anticoagulant treatment, 84 of them have caught a therapeutic accident so a frequency of 5,3 per cent. It concerns 98 therapeutic accidents : 89 haemorrhagic spontaneous accidents (11 digestive haemorrhages, 5 cerebro-vascular accidents, 54 hematomas with 18 retro-peritoneals and 11 in musculis rectis abdominis, 9 hematuries, 2 serous haemorrhages, 8 various haemorrhages) ; 8 "induced" haemorrhages, in which 5 after arterial catheterism, and an accident allergic to the phenyl-indane-dione. Nine deceases were revealed : in which 5 are directly attributed to the hemorrhagic accident (3 cerebro-vascular accidents and 2 serous haemorrhages).

Aged↗
PubMed1989

Antiresorptive dose-response relationships across three generations of bisphosphonates.

The first generation of bisphosphonates was discovered in the late 1960s and is characterized by short alkyl or halide side-chains. Well known representatives of this class are 1-hydroxyethane-1,1-bisphosphonate (etidronate) and dichloromethane bisphosphonate (clodronate). The antiresorptive activity of these and other analogues was measured in an assay in which a drug was administered for 7 days to growing rats, followed by a morphological assessment of bone volume. In this model, the first generation analogues have antiresorptive activity at dose levels from 0.1 to 10 mg P/kg. Some first generation analogues are now used to treat metabolic bone disease but, when given orally, their efficacy in aggressive resorptive disease may be limited because of low potency. A second generation of bisphosphonates, characterized by an amino terminal group and a higher antiresorptive potency, includes 3-amino-1-hydroxypropane-1,1-bisphosphonate (pamidronate) and 4-amino-1-hydroxybutane-1,1-bisphosphonate. Their antiresorptive activity in growing rats ranges from 0.01 to 1 mg P/kg. In the 1980s a third generation of bisphosphonates, characterized by a cyclic chain, was synthesized. It includes series of pyridinyl ethane bisphosphonates, pyridinyl aminomethane bisphosphonates, indan bisphosphonates, cyclopentane bisphosphonates, piperidyl ethane bisphosphonates, pyridinyl and piperidyl hydroxyethane bisphosphonates, piperidinylidene aminomethane bisphosphonates, and pyridinyl oxa- and thiomethane bisphosphonates. Several of these show antiresorptive activity in growing rats as low as 0.001 mg P/kg. Many of the first-, second- and third-generation bisphosphonates have been tested in a model of retinoid-induced bone resorption, and in this model the rank ordering of potency is similar, though somewhat larger doses of bisphosphonate are required to block the resorption induced by the retinoid.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Structure activity relationships of resorcinol substituted ring systems.

Dopamine receptor agonist activity was evaluated using resorcinol derivatives of the following ring systems: dopamine, aminotetralin, indan, benzocycloheptane, octahydrobenzo(f)quinoline and octahydrobenzo[g]quinoline. The compounds were evaluated for biological activity using in vitro binding assays, anesthetized cat blood pressure and heart rate, cat cardioaccelerator nerve preparation and rotations of rats with unilateral denervation of the caudate nucleus. Resorcinol substitutions were chosen because one hydroxyl group corresponded to the alpha-conformer of dopamine and the second hydroxyl group corresponded to the beta-conformer of dopamine. Dopamine receptor activity was found primarily with derivatives of aminotetralin and octahydrobenzo[f]quinoline while the other ring systems yielded compounds which were quite inactive. The active resorcinol derivatives were found in the same ring systems where catechol substitution was active in ring positions corresponding to either the alpha- or beta-conformer of dopamine. Likewise in those ring systems where catechol substitution corresponding to the beta-conformer of dopamine were quite inactive, resorcinol substitution in these series was not favorable for activity. The ring systems requirements for alpha- and beta-adrenoceptor agonist activity did not follow the same structural pattern as found for dopamine receptor agonist activity.

Animals↗
PubMed1984

Molecular structures of metabolites and analogues of diethylstilbestrol and their relationship to receptor binding and biological activity.

A series of indanyl derivatives of diethylstilbestrol (DES) have recently been identified as inv vivo metabolites of DES. These compounds are of interest because they possess effective uterine estrogen receptor-binding affinity but poor biological activity. The X-ray crystal structures of three of these derivatives were determined and their conformations were compared with those of estradiol and DES. The more active derivatives, indenestrol A (I) and indenestrol B (II) have nearly identical conformations, in which the overall molecule is highly planar, the phenyl ring is twisted out of the plane of the indene rings by approximately 30 degrees, and the distance between the hydroxyl groups is 11.6 A. In the least active derivative, idanestrol (III), the methyl, ethyl, and phenyl substituents were found to be in the same side of the indane ring so that the molecule is constrained to an L-shape. The crystallographically observed conformations of I, II, III, DES, and estradiol, their competative binding affinities, and their in vivo biological activities are consistent with the proposal that the steroid A-ring plays a dominant role in initiating receptor binding while the D-ring orientation relative to the A-ring has a more decisive influence upon activity. The reduction in estrogen receptor-binding affinity and associated reduced activity of III is almost certainly due to its L-shape conformation. The extended conformation of I and II in which both phenolic rings are exposed permitting ready access to both surfaces of either ring probably accounts for the ability of these derivatives to compete so successfully with estradiol for estrogen receptor binding. There are eight different ways in which the molecules of the racemic mixtures of I and II could initiate receptor binding. The reduced biological activity of I and II is probably due to the fact that not all eight binding orientations are compatible with eliciting estrogenic response. Comparison of the observed conformations of I, II, DES, and estradiol suggests that it is the alpha-ring of I and II that minics the steroid A-ring in receptor binding, and that two of the four possible alpha-ring/A-ring matches are most conducive to eliciting hormone activity.

Animals↗
PubMed1982

Reagents for the chemical development of latent fingerprints: synthesis and properties of some ninhydrin analogues.

In an attempt to design new reagents for the chemical development of latent fingerprints, a number of ninhydrin analogues were synthesized and their reactions with latent fingerprints on paper were studied. The ring-fused and substituted ninhydrins developed latent fingerprints with a sensitivity similar to that of ninhydrin. The most promising of the group was 2,2-dihydroxybenz[f]indane-1,3-dione, which developed latent fingerprints as dark green images with excellent resolution.

Color↗