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Perturbation of hydroxyl radical accumulation by subinhibitory concentrations of 2,2'-bipyridyl plus thiourea protects Escherichia coli from being killed by 3 lethal antimicrobial classes. Here, we show that 2,2'-bipyridyl plus thiourea delays and/or reduces antimicrobial killing of Staphylococcus aureus by daptomycin, moxifloxacin, and oxacillin. While the protective effect of 2,2'-bipyridyl plus thiourea varied among strains and compounds, the data support the hypothesis that hydroxyl radical enhances antimicrobial lethality.

Background and Purpose: Intracerebroventricularly injected tachykinin NK(3) receptor (R) antagonists normalize mean arterial blood pressure (MAP) in spontaneously hypertensive rats (SHR). This study was pursued to define the role played by NK(3)R located on dopamine neurones of the ventral tegmental area (VTA) in the regulation of MAP in SHR., Experimental Approach: SHR (16 weeks) were implanted permanently with i.c.v. and/or VTA guide cannulae. Experiments were conducted 24 h after catheterization of the abdominal aorta to measure MAP and heart rate (HR) in freely behaving rats. Cardiovascular responses to i.c.v. or VTA-injected NK(3)R agonist (senktide) and antagonists (SB222200 and R-820) were measured before and after systemic administration of selective antagonists for D(1)R (SCH23390), D(2)R (raclopride) or non-selective D(2)R (haloperidol), and after destruction of the VTA with ibotenic acid., Key Results: I.c.v. or VTA-injected SB222200 and R-820 (500 pmol) evoked anti-hypertension, which was blocked by raclopride. Senktide (10, 25, 65 and 100 pmol) elicited greater increases of MAP and HR when injected in the VTA, and the cardiovascular response was blocked by R-820, SCH23390 and haloperidol. VTA-injected SB222200 prevented the pressor response to i.c.v. senktide, and vice versa, i.c.v. senktide prevented the anti-hypertension to VTA SB222200. Destruction of the VTA prevented the pressor response to i.c.v. senktide and the anti-hypertension to i.c.v. R-820., Conclusions and Implications: The NK(3)R in the VTA is implicated in the maintenance of hypertension by increasing midbrain dopaminergic transmission in SHR. Hence, this receptor may represent a therapeutic target in the treatment of hypertension., (© 2010 The Authors. British Journal of Pharmacology © 2010 The British Pharmacological Society.)

Several health benefits, including protection from tumors at various anatomic sites, such as the lungs, stomach, and prostate gland, have been attributed to tomatoes and tomato-based products. Among tomato carotenoids, lycopene is the most active antioxidant, although it has many other biological effects, but data on its antimutagenic effects are scarce and often discrepant. The aim of our work was to determine the protective effects of lycopene, with regard to mutagenicity, via two indirect mutagens/carcinogens-2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and aflatoxin B₁ (AFB₁) and the direct mutagen/carcinogen N-nitroso-N-methylurea (MNU)--using the Ames and micronucleus tests. The significant, dose-dependent, antimutagenic effects of two concentrations of lycopene (30 μg and 300 μg per plate) were demonstrated at various concentrations of both AFB₁ and IQ in two strains of Salmonella typhimurium (TA98 and TA100). The protective effects of lycopene relative to MNU were lower in comparison to its protective effects relative to AFB₁ and IQ. Mice treated for 3 days with different doses of lycopene (either 25 or 50 mg/kg of body weight) prior to administration of individual mutagens resulted in a significant reduction of micronuclei numbers in the micronucleus test. Tomato purée (tested using the Ames test and AFB(1)) revealed a much stronger, dose-dependent, antimutagenic effect compared with corresponding doses of pure lycopene. Results indicate that lycopene has antimutagenic effects, although the effects are lower than that of tomato purée, which contains a complex mixture of bioactive phytochemicals. The antimutagenic effect is connected with the chemoprotective role of lycopene, tomatoes, and tomato products in the prevention of carcinogenesis.

Background: The long duration of the current tuberculosis (TB) treatment is demanding and warrants the development of new drugs. Moxifloxacin shows promising results and may be combined with rifampicin to shorten the duration of TB treatment. Rifampicin induces the phase II metabolic enzymes that are involved in the biotransformation of moxifloxacin. Therefore, the interaction between rifampicin and moxifloxacin should be investigated., Patients and Methods: Nineteen Indonesian patients with pulmonary TB who were in the last month of their TB treatment completed a 1-arm, 2-period, fixed-order pharmacokinetic study. In phase 1 of the study, they received 400 mg of moxifloxacin every day for 5 days in addition to 450 mg of rifampicin and 600 mg of isoniazid 3 times per week. In phase 2 of the study, after a 1-month washout period, patients received moxifloxacin for another 5 days (without rifampicin and isoniazid). A 24-h pharmacokinetic curve for moxifloxacin was recorded on the last day of both study periods, and its pharmacokinetic parameters were evaluated for an interaction with rifampicin, using a bioequivalence approach., Results: Coadministration of moxifloxacin with rifampicin and isoniazid resulted in an almost uniform decrease in moxifloxacin exposure (in 18 of 19 patients). The geometric means for the ratio of phase 1 area under the curve to phase 2 area under the curve and for the ratio of phase 1 peak plasma concentration to phase 2 peak plasma concentration were 0.69 (90% confidence interval, 0.65-0.74) and 0.68 (90% confidence interval, 0.64-0.73), respectively. The median time to reach peak plasma concentration for moxifloxacin was prolonged from 1 h to 2.5 h when combined with rifampicin and isoniazid (P=.003)., Conclusions: Coadministration of moxifloxacin with intermittently administered rifampicin and isoniazid results in reduced moxifloxacin plasma concentrations, which is most likely the result of induced glucuronidation or sulphation by rifampicin. Further studies are warranted to evaluate the impact of the interaction on the outcome of TB treatment.

A role of ATP in nonadrenergic, noncholinergic (NANC) relaxations was examined in the Wistar rat jejunum. Electrical field stimulation (EFS) induced NANC relaxation of longitudinal muscle of the jejunal segments in a frequency-dependent manner. A purinoceptor antagonist, adenosine 3'-phosphate 5'-phosphosulfate (A3P5PS, 100 muM) inhibited the relaxation: relaxations induced by EFS at lower or higher frequencies were either completely or partially inhibited, respectively. After the jejunal segments had been desensitized to ATP, the relaxations were decreased to the same extent as those inhibited by A3P5PS. An inhibitor of small conductance Ca(2+)-activated K(+) channels (SK channels), apamin (100 nM), completely inhibited EFS-induced relaxations. Treatment of the segments with an inhibitor of sarcoplasmic reticulum Ca(2+)-ATPase, thapsigargin (1 muM), significantly inhibited the relaxations. The exogenous ATP-induced relaxation of longitudinal muscle occurred with a concomitant decrease in intracellular Ca(2+) levels. Apamin and thapsigargin abolished these ATP-induced responses. A3P5PS significantly inhibited the inhibitory junction potentials which were induced in the longitudinal muscle cells. In addition, apamin significantly inhibited the hyperpolarization that was induced by exogenous ATP in the cells. These findings in the Wistar rat jejunum suggest that ATP participates in the NANC relaxation via activation of SK channels induced by Ca(2+) ions that are released from the thapsigargin-sensitive store site.

Aim: To investigate the possibility whether THPB-18 (l-12-shloroscoulerine) possesses the D1 agonist-D2 antagonist action on meso-accumbens-mPFC DA system., Methods: Single unit spontaneous firing activity was recorded in the nucleus accumbens (NAc) neurons of naive and unilateral-6-hydroxydopamine (6-OHDA)-lesioned Sprague-Dawley rats. The effects of drugs applied intravenously or iontophoretically were determined by the change of firing rates., Results: Under normal conditions, the systemic administration of THPB-18 produced a decrease-increase biphasic firing pattern in the NAc neurons during cumulative doses. High dose of THPB-18 was capable of reversing the inhibition induced by both D2 agonist LY171555 and D1/D2 agonist APO on NAc firing activity. Spiperone pretreatment could not block the high dose of THPB-18-induced firing rate increase, which was reversed by the D1 selective antagonist SCH23390. The tested NAc neurons were effectively inhibited by iontophoretically applied THPB-18 in 90 % of 6-OHDA-lesioned rats, while THPB-18 caused variable effects on the firing of NAc neurons in the neurons of unlesioned rats. The inhibitory effect of THPB-18 was blocked by iontophoretic application of SCH23390, but not D2 antagonist spiperone., Conclusion: Similar to L-stepholidine, THPB-18 also possesses the D1 agonistic-D2 antagonistic dual action on the VTA-NAc DA system.

Background: The effect of pitavastatin on the mRNA levels of apolipoprotein (apo) A-I, peroxisome proliferator-activated receptor alpha (PPARalpha), cholesterol 7alpha-hydroxylase (CYP7A1), and farnesoid X receptor (FXR) in HepG2 cells was examined to establish whether pitavastatin affects bile acid synthesis and if so, to determine a possible molecular mechanism., Methods and Results: HepG2 cells were cultured in serum-free Dulbecco's modified Eagle medium for 18 h before drug treatment. Total RNA was extracted at set times and mRNA levels were quantified by reverse transcription-real time polymerase chain reaction. Pitavastatin at 0.1, 1, 5, and 10 micromol/L increased the mRNA levels of apo A-I, PPARalpha, CYP7A1, and FXR in a dose-dependent manner. The mRNA levels of apo A-I, PPAR alpha, CYP7A1, and FXR similarly increased with increasing doses of pitavastatin. Coincubation of mevalonate (4 mmol/L) with pitavastatin (5 micromol/L) reversed the inductive effects of pitavastatin on the mRNA levels of these genes, indicating that the inductive effects of pitavastatin were related to its inhibition of HMG-CoA reductase., Conclusions: Pitavastatin increased the mRNA levels of CYP7A1 in HepG2 cells, suggesting that increased conversion of cholesterol to bile acids may be the mechanism for its potent low-density lipoprotein cholesterol-lowering effects.

The effects of the flavonoids quercetin, apigenin and chrysin (10 microM) on the genetic toxicity of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and benzo[a]pyrene (BaP) was investigated at sub-cytotoxic concentrations in Chinese hamster V79 cells expressing human or rat cytochromes P450. In V79 r1A2-NH and V79 h1A1-MZ cells, none of the flavonoids increased DNA strand breaks (SB) (measured by the Comet assay) or produced detectable DNA adducts (measured by 32P-post-labelling). Neither IQ nor BaP produced DNA damage in the absence of expressed CYP1A2 or CYP1A1, respectively. DNA damage measured as SB and DNA adducts was detectable in V79 r1A2-NH cells expressing rat CYP1A2 when treated with IQ (2.5-50 microM) and this was inhibited by quercetin. Likewise, DNA damage (SB and DNA adducts) was elevated in V79 h1A1-MZ cells expressing human CYP1A1 when treated with BaP (0.1-0.5 microM) and this was inhibited by chrysin and apigenin, but not by quercetin. The specificity of CYP1A1 inhibition by chrysin and apigenin and CYP1A2 inhibition by quercetin was confirmed by ethylresorufin O-deethylase assay.

1. It has been suggested that osteopontin promotes the development of atherosclerosis, especially under diabetic conditions. 2. In the present study, we found that NK-104, a new potent synthetic inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, reduced osteopontin expression both at protein and mRNA levels in cultured rat aortic smooth muscle cells. 3. The inhibitory effect of NK-104 was almost completely reversed by mevalonate, suggesting that mevalonate or its metabolites play important roles in the regulation of osteopontin expression. 4. Furthermore, oral administration of NK-104 (3 mg kg(-1) day(-1) for 7 days) effectively suppressed abnormally upregulated expression of osteopontin mRNA in the aorta and kidney of streptozotocin-induced diabetic rats. 5. These data support a notion that NK-104 is a suitable drug for the treatment of diabetic patients with hypercholesterolaemia.

Multiple drug resistance (MDR) mechanisms are known to limit the effectiveness of some cancer chemotherapies, probably through enhancing P-glycoprotein-mediated drug efflux from mammalian cells. Similar mechanisms appear to act in other organisms, including bacteria, and may affect not only the toxicity but also the mutagenicity of certain chemicals. At least in some experimental situations, MDR can be overcome through concomitant treatment of the cells with various types of inhibitors. Two MDR inhibitors, verapamil, a calcium channel blocker, and trifluoperazine, a calmodulin inhibitor, were assayed for their ability to modulate the potency of nine mutagens with varying mechanisms of action in various Salmonella typhimurium his- strains. Neither verapamil nor trifluoperazine affected the direct mutagenicity of sodium dichromate and 2-methoxy-6-chloro-9[3-(2-chloroethyl)amino-propyl-amino] dihydrochloride (ICR 191) or the S9-mediated mutagenicity of benzo[a]pyrene and 2-amino-3,4-dimethyl-amidazo[4,5-f]quinoline (MeIQ). Both modulators enhanced the direct mutagenicity of doxorubicin. Moreover, trifluoperazine sharply increased the S9-mediated mutagenicity of cyclophosphamide and 2-aminofluorene, while it consistently decreased the mutagenicity of 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2). The contrasting effect towards the aromatic amine 2-aminofluorene and the heterocyclic amine Trp-P-2, representative of important chemical families responsible for the bacterial mutagenicity of cigarette smoke, may explain the observed lack of influence of trifluoperazine on the mutagenicity of a cigarette smoke condensate. These observations extend the known range of chemical types whose mutagenicity can be modulated by inhibitors of MDR and suggest that there may be value in adding MDR inhibitors, especially trifluoperazine, to optimize the detection of mutagenicity by certain types of chemicals in the Salmonella/mammalian microsome mutagenicity test.

Male F344 rats were exposed for 8 weeks to extracts of green tea (2% w/v) or black tea (1% w/v), or to 0.1% dietary indole-3-carbinol (I3C). In weeks 3 and 4 of the study, rats were given 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) every other day by oral gavage (50 mg/kg body wt) in order to induce aberrant crypt foci (ACF) in the colon. Compared with controls given IQ alone, all three inhibitors reduced the number of total aberrant crypts per colon, and green tea and I3C inhibited significantly the mean number of ACF (P < 0.05). Rats pre-treated with green tea, black tea, or I3C and given a single p.o. injection of 50 mg IQ/kg body wt 24-48 h before sacrifice had reduced levels of IQ-DNA adducts in the liver, and excreted lower amounts of IQ and other promutagens in the urine and feces. Inhibitors also reduced the excretion of IQ-sulfamate in the urine, but increased the relative amounts of IQ-5-O-sulfate and IQ-5-O-glucuronide. Western blotting together with assays for 7-ethoxyresorufin O-deethylase and methoxyresorufin O-demethylase established that I3C preferentially induced cytochrome P4501A1 over 1A2, consistent with the altered profile of urinary metabolites. However, both teas caused slight induction of cytochrome P4501A2 versus 1A1, which would be predicted to enhance the activation of IQ. Thus, green tea and black tea are likely to protect against IQ-DNA adducts and ACF by mechanisms other than induction of cytochromes P450, such as inhibition of enzymes which activate IQ or the scavenging of reactive intermediates.

The antimutagenic potencies of the juices of 28 fruits and 34 vegetables commonly consumed in Germany were investigated with respect to the mutagenic activities induced by 2-amino-3-methyl[4,5-f]-quinoline (IQ), and in part by 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) or 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) in Salmonella typhimurium TA98 and TA100. With IQ, weak to strong antimutagenic activities were found in 68% of the fruits and 73% of the vegetables that were tested. In fruits, strong antimutagenic activities were detected in bananas, blackberries, blueberries, sweet and sour cherries, blackcurrants and redcurrants, pineapple and watermelon. Moderate antimutagenic activities were detected in greengage, kiwi, mangos, honeydew melons and plums. Weak antimutagenic activities were detected in apple, apricot, mirabelle, pears, peaches and strawberries, whereas white and red grapes and raspberries were inactive, and gooseberries and citrus fruits in general possessed marginal or no antimutagenic activities. In vegetables, strong to moderate antimutagenic activities were found for all cruciferous vegetables, except Chinese cabbage, which had only weak antimutagenic activity. Other vegetables with strong antimutagenic activities were beets, chives, horseradish, onions, rhubarb and spinach. Moderate antimutagenic activities were found with green beans and tomatoes, weak activities in eggplant, garden cress, many lettuces, leeks, mangold, cucumber, pumpkin, radish and summer squash. Asparagus, carrots, fennel leaves, parsley, green peppers and radishes were inactive. When fruit and vegetable juices were heated, a considerable reduction of antimutagenic potencies was seen with apple, apricot, kiwi, pineapple, beets, cabbage (Chinese, Savoy, red and white), cauliflower, leafy lettuce, cucumber, onions, radish and rhubarb. Antimutagenic factors in blackberries, blueberries, sweet and sour cherries, honeydew melons, mirabelle, plums, strawberries, Brussels sprouts, chicory greens, eggplant, garden cress, mangold, pumpkin, lamb's lettuce and spinach were, however, remarkably heat stable. Antimutagenic potencies in bananas, blackcurrants and redcurrants, greengages, gooseberries, mangos, watermelon, green beans, kohlrabi, horseradish, tomatoes and chives were partially reduced. Antimutagenic activities in the juices of eight apple cultivars were moderate in two, weak in four, and marginal or absent in two. No major differences, however, were detected in five batches of oranges and three batches each of grapefruits, asparagus, green beans, broccoli, cauliflower, spinach and tomatoes. No (or only minor) differences were seen between IQ, MeIQ and MeIQx and tester strains TA98 and TA100. Pineapple and celeriac juices inhibited the enzymatic system responsible for the activation of IQ, but had no desmutagenic activity. Peroxidase activity found to be present in broccoli, cauliflower, green beans and tomatoes may contribute to antimutagenic activities in these vegetables.

EMD 53998 (a thiadiazinone) is a novel inotropic substance that increases the Ca2+ sensitivity of the myofilaments in skinned cardiac fibers and has been found to have similar effects in intact cardiac muscle. However, the compound also possesses the ability to inhibit phosphodiesterase III, indicating that its actions in intact cardiac muscle are likely to be complex. The present study was carried out to investigate the possibility that the optical isomers of EMD 53998--(+)EMD 57033 and (-)EMD 57439--which have recently been shown to possess a separation of sensitization and phosphodiesterase inhibition in subcellular preparations, might also demonstrate this separation of activities in intact cardiac muscle. The experiments were performed on isolated ferret papillary muscles, which were contracting isometrically. In some preparations, the photoprotein aequorin was injected into superficial cells to measure intracellular Ca2+ as well as force. (+)EMD 57033 caused a substantial positive inotropic effect that was associated with prolongation of the twitch, reduction in the amplitude of the Ca2+ transient, and abbreviation of the Ca2+ transient. This is the profile expected of a Ca(2+)-sensitizing compound. Conversely, (-)EMD 57439 caused a less marked positive inotropic effect that was associated with an abbreviation of the twitch, an increase in the amplitude of the Ca2+ transient, and an abbreviation of the Ca2+ transient. This is the profile expected of an agent producing its inotropic effect by increasing cAMP (e.g., phosphodiesterase inhibition). The results indicate that the optical isomers of EMD 53998 possess a remarkable separation of Ca(2+)-sensitizing and phosphodiesterase-inhibiting activities in intact cardiac muscle. These actions were additive and could account for the effects observed with EMD 53998. (+)EMD 57033 appears to be the first inotropic agent that acts predominantly by increasing myofilament calcium sensitivity.

The ability of the plant phenol ellagic acid to inhibit the mutagenicity of the food mutagen IQ was evaluated using Salmonella typhimurium strain TA98 in the Ames mutagenicity test. Ellagic acid caused a concentration-dependent decrease in the S-9- and microsome-mediated mutagenicity of IQ. The plant phenol did not interact directly with the IQ-derived mutagenic species and did not modify the cytosol-mediated activation of the promutagen. At the concentrations used in the mutagenicity studies, ellagic acid failed to inhibit microsomal mixed-function oxidase activity, including that mediated by the P450I family responsible for the bioactivation of IQ, despite being an essentially planar molecule as indicated by computer-graphic analysis. The inhibitory effect of ellagic acid was independent of its ability to chelate Mg2+. However, pre-incubation of ellagic acid with the bacteria, followed by removal of the plant phenol, did not completely prevent the inhibitory effect of the phenol on the mutagenicity of IQ. Intraperitoneal administration of ellagic acid to rats caused a decrease in total cytochrome P-450 levels and related activities as well as in cytosolic glutathione S-transferase activity. Finally, the possibility that the reported anticarcinogenic action of ellagic acid reflects nothing more than non-selective destruction of hepatic cytochromes P-450, and thus reduced chemical activation, is considered.

Grilled ground beef contains a number of carcinogens, including aminoimidazoazaarenes, such as 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), as well as anticarcinogenic substances, such as heat-generated derivatives of linoleic acid (CLA). In the present study, CLA was administered by gavage every other day to young adult CDF1 mice for a period of 45 days (50 microliters/48 hr for days 1-24 and 100 microliters/48 hr for days 25-45), using trioctanoin as a control. On day 46 all animals received a single oral dose (50 mg/kg) of IQ and tissues were collected 24 hr later. Tissue DNA was purified and analysed for IQ-DNA adducts by 32P-postlabelling assays. Compared with controls, CLA treatment caused a 43.1 and 31.8% inhibition of adduct formation in the livers of male and female mice, respectively. In the lung and large intestine CLA had a 74.2 and 39.4% inhibitory effect, respectively, in the female only, whereas there was no effect in the stomach or small intestine of either sex. In the kidneys of females, CLA treatment inhibited IQ-DNA adduct formation almost completely (95.2%), whereas in the kidneys of males CLA had no effect. It is concluded that CLA inhibits IQ-DNA adduct formation in certain IQ target organs (liver and lung) and non-target organs (large intestine, kidney), but is inactive in other target organs (stomach) and non-target organs (small intestine) of the CDF1 mouse.

The herbs Rheum palmatum B and Polygonum cuspidatum S are frequently used as laxatives and anticancer drugs in Chinese medicine. The antimutagenic activity of these herbs as well as their active component emodin was examined in Salmonella typhimurium TA98. The crude extracts and emodin induced a dose-dependent decrease in the mutagenicity of benzo[a]pyrene (B[a]P), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2). Furthermore, emodin reduced the mutagenicity of IQ by direct inhibition of the hepatic microsomal activation and not by interaction with proximate metabolites of IQ and/or by modification of DNA repair processes in the bacterial cell.

1. (-)-Isoprenaline, salbutamol, orciprenaline and quinterenol injected intravenously decreased the tension and degree of fusion of incomplete tetanic contractions of the soleus muscle of the anaesthetized cat.2. Under the most sensitive conditions, the smallest effective dose of (-)-isoprenaline was of the order of 0.01 mug/kg intravenously. Salbutamol was usually 6-10 times, orciprenaline 20-30 times and quinterenol about 35 times less potent than isoprenaline. The effects of salbutamol were about 1.6 times, of orciprenaline about 1.8 times and of quinterenol more than 20 times as long lasting as those of (-)-isoprenaline.3. The effects of the sympathomimetic amines were blocked by propranolol, H56/28, H35/25 and butoxamine but not by ICI 50172. The combined results with agonists and antagonists indicate that the receptors involved can be classified as of the beta(2) type.4. The effect of the amines on the cat soleus muscle appears to be analogous to that causing enhancement of physiological tremor in man, which suggests that skeletal muscle tremor may be an occasional unwanted side effect of the use of these bronchodilators.