Involvement of LTB4 in zymosan-induced joint nociception in mice: participation of neutrophils and PGE2

Leukotriene B4 (LTB4) mediates different inflammatory events such as neutrophil migration and pain. The present study addressed the mechanisms of LTB4-mediated joint inflammation-induced hypernociception. It was observed that zymosan-induced articular hypernociception and neutrophil migration were reduced dose-dependently by the pretreatment with MK886 (1-9 mg/kg; LT synthesis inhibitor) as well as in 5-lypoxygenase-deficient mice (5LO(-/-)) or by the selective antagonist of the LTB(4) receptor (CP105696; 3 mg/kg). Histological analysis showed reduced zymosan-induced articular inflammatory damage in 5LO(-/-) mice. The hypernociceptive role of LTB4 was confirmed further by the demonstration that joint injection of LTB4 induces a dose (8.3, 25, and 75 ng)-dependent articular hypernociception. Furthermore, zymosan induced an increase in joint LTB4 production. Investigating the mechanism underlying LTB4 mediation of zymosan-induced hypernociception, LTB4-induced hypernociception was reduced by indomethacin (5 mg/kg), MK886 (3 mg/kg), celecoxib (10 mg/kg), antineutrophil antibody (100 mug, two doses), and fucoidan (20 mg/kg) treatments as well as in 5LO(-/-) mice. The production of LTB4 induced by zymosan in the joint was reduced by the pretreatment with fucoidan or antineutrophil antibody as well as the production of PGE2 induced by LTB4. Therefore, besides reinforcing the role of endogenous LTB4 as an important mediator of inflamed joint hypernociception, these results also suggested that the mechanism of LTB4-induced articular hypernociception depends on prostanoid and neutrophil recruitment. Furthermore, the results also demonstrated clearly that LTB4-induced hypernociception depends on the additional release of endogenous LTs. Concluding, targeting LTB4 synthesis/action might constitute useful therapeutic approaches to inhibit articular inflammatory hypernociception.

Simultaneous determination of fixed dose combination of nebivolol and valsartan in human plasma by liquid chromatographic-tandem mass spectrometry and its application to pharmacokinetic study

A rapid, sensitive and accurate liquid chromatographic-tandem mass spectrometry method is described for the simultaneous determination of nebivolol and valsartan in human plasma. Nebivolol and valsartan were extracted from plasma using acetonitrile and separated on a C18 column. The mobile phase consisting of a mixture of acetonitrile and 0.05 mM formic acid (50:50 v/v, pH 3.5) was delivered at a flow rate of 0.25 ml/min. Atmospheric pressure ionization (API) source was operated in both positive and negative ion mode for nebivolol and valsartan, respectively. Selected reaction monitoring mode (SRM) using the transitions of m/z 406.1-->m/z 150.9; m/z 434.2-->m/z 179.0 and m/z 409.4-->m/z 228.1 were used to quantify nebivolol, valsartan and internal standard (IS), respectively. The linearity was obtained over the concentration range of 0.01-50.0 ng/ml and 1.0-2000.0 ng/ml and the lower limits of quantitation were 0.01 ng/ml and 1.0 ng/ml for nebivolol and valsartan, respectively. This method was successfully applied to the pharmacokinetic study of fixed dose combination (FDC) of nebivolol and valsartan formulation product after an oral administration to healthy human subjects.

Modeling and Simulation to Support Dose Selection and Clinical Development of SC-75416, a Selective COX-2 Inhibitor for the Treatment of Acute and Chronic Pain

Pharmacokinetic/pharmacodynamic (PK/PD) models were developed and clinical trial simulations were conducted to recommend a study design to test the hypothesis that a dose of SC-75416, a selective cyclooxygenase-2 inhibitor, can be identified that achieves superior pain relief (PR) compared to 400 mg ibuprofen in a post-oral surgery pain model. PK/PD models were developed for SC-75416, rofecoxib, valdecoxib, and ibuprofen relating plasma concentrations to PR scores using a nonlinear logistic-normal model. Clinical trial simulations conducted using these models suggested that 360 mg SC-75416 could achieve superior PR compared to 400 mg ibuprofen. A placebo- and positive-controlled parallel-group post-oral surgery pain study was conducted evaluating placebo, 60, 180, and 360 mg SC-75416 oral solution, and 400 mg ibuprofen. The study results confirmed the hypothesis that 360 mg SC-75416 achieved superior PR relative to 400 mg ibuprofen (DeltaTOTPAR6=3.3, P<0.05) and demonstrated the predictive performance of the PK/PD models.

A Randomized, Double-Blind, Placebo-Controlled Parallel-Group Study to Assess the Efficacy and Safety of Nebivolol, a Novel β-Blocker, in Patients With Mild to Moderate Hypertension

This double-blind, multicenter, randomized placebo-controlled study evaluated the antihypertensive efficacy and safety of nebivolol, a selective beta1-adrenoreceptor blocker with vasodilating effects, in patients with mild to moderate hypertension (sitting diastolic blood pressure [SiDBP] > or =95 mm Hg and < or =109 mm Hg). A total of 909 patients were randomized to receive placebo or nebivolol 1.25, 2.5, 5, 10, 20, or 40 mg once daily for up to 84 days. The primary end point was the change in trough SiDBP from baseline to study end. Nebivolol significantly reduced trough SiDBP (8.0-11.2 mm Hg compared with 2.9 mm Hg with placebo; P<.001) and trough sitting systolic blood pressure (a 4.4-9.5-mm Hg decrease compared with a 2.2-mm Hg increase [corrected] with placebo; P< or =.002). The overall adverse event experience was similar in the nebivolol (46.1%) and placebo (40.7%) groups (P=.273). Once-daily nebivolol is an effective antihypertensive in mild to moderate hypertensive patients.

A highly sensitive canine telemetry model for detection of QT interval prolongation: Studies with moxifloxacin, haloperidol and MK-499

INTRODUCTION

Preclinical evaluation of delayed ventricular repolarization manifests electrocardiographically as QT interval prolongation and is routinely used as an indicator of potential risk for pro-arrhythmia (potential to cause Torsades de Pointes) of novel human pharmaceuticals. In accordance with ICH S7A and S7B guidelines we evaluated the sensitivity and validity of the beagle dog telemetry (Integrated Telemetry Services (ITS)) model as a preclinical predictor of QT interval prolongation in humans.

METHODS

Cardiovascular monitoring was conducted for 2 h pre-dose and 24 h post-dosing with moxifloxacin (MOX), haloperidol (HAL), and MK-499, with a toxicokinetic (TK) evaluation in a separate group of dogs. In both cardiovascular and TK studies, MOX (0, 10, 30 and 100 mg/kg), HAL (0, 0.3, 1, 3 mg/kg) and MK-499 (0, 0.03, 0.3 and 3 mg/kg) were administered orally by gavage in 0.5% methylcellulose. Each dog received all 4 doses using a dose-escalation paradigm. Inherent variability of the model was assessed with administration of vehicle (0.5% methylcellulose) alone for 4 days.

RESULTS

Significant increases in QT(c) were evident with 10, 30 and 100 mg/kg of MOX (C(max)< or =40 microM), 0.3, 1 and 3 mg/kg of HAL (C(max)< or =0.36 microM) and 0.3 and 3 mg/kg of MK-499 (C(max)< or =825 nM) with peak increases of 45 (20%), 31 (13%), and 45 (19%) ms, respectively (p< or =0.05).

DISCUSSION

In conclusion, we have demonstrated that the ITS-telemetry beagle dog exhibits low inherent intra-animal variability and high sensitivity to detect small but significant increases in QT/QT(c) interval ( approximately 3-6%) with MOX, HAL and MK-499 in the same range of therapeutic plasma concentrations attained in humans. Therefore, this dog telemetry model should be considered an important preclinical predictor of QT prolongation of novel human pharmaceuticals.

Tolerability and dose-related effects of nebivolol in elderly patients with heart failure: data from the Study of the Effects of Nebivolol Intervention on Outcomes and Rehospitalisation in Seniors with Heart Failure (SENIORS) trial

BACKGROUND

The SENIORS trial showed that nebivolol reduced the risk of death or cardiovascular (CV) hospitalization in elderly patients with heart failure (HF). We aimed to assess tolerability and dose-related effects of the beta-blocker nebivolol in elderly patients from the SENIORS trial.

METHODS

Patients assigned to nebivolol (n = 1031) were classified into 4 groups, according to the dose achieved at the end of titration phase (maintenance dose): 0 mg (n = 74), low dose (1.25 or 2.5 mg, n = 142), medium dose (5 mg, n = 127), and target dose (10 mg, n = 688) and compared with those allocated to placebo (n = 1030). Age, sex and ejection fraction were similar between the groups, but prior myocardial infarction, coronary revascularization, and serum creatinine levels were lower in patients who achieved higher maintenance doses of nebivolol.

RESULTS

After adjustment, all-cause mortality or CV hospitalization was significantly reduced in the 10 mg dose group compared with placebo (hazard ratio [HR] 0.75, 95% CI 0.63-0.90) which was similar to the medium dose group (HR 0.73, 95% CI 0.52-1.02). The low dose group had an apparently lower benefit (HR 0.88, 95% CI 0.64-1.20), whereas patients unable to tolerate any dose of nebivolol had an increased risk of death or CV hospitalization (HR 1.95, 95% CI 1.38-2.75).

CONCLUSIONS

The benefits of nebivolol in elderly patients with HF appear to be related to the maintenance dose achieved. Patients unable to tolerate any dose have the worst prognosis.

Methamphetamine-induced locomotor activity and behavioral sensitization: are dopamine d3 receptors involved?

Drug sensitization is a behavioral phenomenon that occurs following repeated administration of methamphetamine (METH) and similar CNS stimulants. The mechanism of drug sensitization is unknown, but is believed to be due to downregulation of dopamine D3 receptors. It is hypothesized that repeated administration of dopamine D3 agonists results in downregulation of D3 receptors in methamphetamine-induced (METH-IND) sensitization. Furthermore, repeated administration of dopamine D3 antagonists and METH cause upregulation of D3 receptors and block METH-IND sensitization. The objective of this study was to determine the role of D3 receptors in METH-IND sensitization. To test these hypotheses, male mice received chronic injections (i.p.) of 2 mg/kg of the dopamine D3 agonist, PD128907 plus 0.5 mg/kg of METH or 8 mg/kg of D3 antagonist, U99194A and 0.5 mg\kg of METH daily for 7-days. Drugs were withdrawn on day 8, and METH-IND sensitization was determined on day 18. Locomotor activity was measured for 75 minutes immediately after METH administration in an activity monitor. Acute administration of PD128907 decreased METH-IND locomotion, p < 0. 01, and acute U99194A increased it. However, chronic administration of these drugs did not alter the locomotor effects of METH (p > 0.05). These findings support in-part the hypothesis that dopamine D3 receptors are downregulated in METH-IND sensitization.

Transport of decursin and decursinol angelate across Caco-2 and MDR-MDCK cell monolayers: in vitro models for intestinal and blood-brain barrier permeability

Decursin (DE) and decursinol angelate (DA) were isolated from the roots of Angelica gigas (Apiaceae) and purified by HPLC. DE and DA have been reported to exhibit significant neuropharmacological activities, but their intestinal transport and permeability in terms of CNS penetration across the blood-brain barrier (BBB) are unknown. This study was undertaken to evaluate the IN VITRO intestinal and BBB transport of DE and DA using Caco-2 and MDR-MDCK cell monolayer models, respectively. The bidirectional transport of DE and DA across Caco-2 and MDR-MDCK monolayers was examined for 2 hours. Integrity of the monolayer was determined by TEER value and by monitoring the transport of Lucifer yellow (Ly) across the monolayers. Quantitation of DE and DA was performed by HPLC. DE and DA exhibited bidirectional transport with a Papp value in the range of 9.0-12.0x10(-6) cm/sec and 7.2-11.7x10(-6) cm/sec in Caco-2 and MDR-MDCK monolayers, respectively. The TEER values were in the range of 410-440 and 1170-1230 ohm cm2 for Caco-2 and MDR-MDCK monolayers, respectively. Ly measurement, the fluorescent marker of passive paracellular diffusion, resulted in Papp values of 2.5-5.0x10(-6) in Caco-2 and 6.0-8.0x10(-6) cm/sec in MDR-MDCK monolayers, confirming that the monolayer integrity was intact at the end of the experiment. Caco-2:human colonic adenocarcinoma DA:decursinol angelate DE:decursin Ly:Lucifer yellow MDCK:Madin-Darby canine kidney MDR:multidrug resistant Papp:apparent permeability TEER:transepithelial electrical resistance.

Comparative effects of conventional B-blockers and nebivolol on psychomotor performances in healthy volunteers: a preliminary report

The present study was under taken to assess the comparative effects of nebivolol with propranolol and atenolol on psychomotor performances. Thirty healthy volunteers were randomized into three groups with n=10 in each group. Each subject received single dose of one of the three medications (nebivolol 5 mg, atenolol 50 mg and propranolol 40 mg) in morning (9:00 AM). Just before administering the drug, the pre-drug scores were taken, followed by post drug score obtained for consecutive six hours. Psychomotor assessment was carried out by three tests Simple Reaction Timer (SRT), Critical Flicker Fusion Frequent Threshold (CFFT) and Digit Cancellation Test (DCT). The results of present study indicate that single doses of atenolol and propranolol produced significant impairment of psychomotor performance. Nebivolol also impaired psychomotor performance tests in the similar fashion to atenolol and propranolol. Hence, the findings of the present study correlate with the lipophilic nature of the nebivolol.

Quantitation of Armillarisin A in human plasma by liquid chromatography–electrospray tandem mass spectrometry

A rapid and sensitive LC-MS/MS method for quantifying Armillarisin A in human plasma after a single oral dose (40 mg) has been developed and validated. Sample preparation used liquid-liquid extraction with a mixture of diethyl ether-dichloromethane (60:40, v/v) in an acidic environment. The retention times of Armillarisin A and the internal standard, probenecid, were 1.63 and 1.78 min, respectively. The calibration curve was linear over the range 0.15-50 ng/mL with a limit of quantitation of 0.15 ng/mL. The coefficient of variation as a measure of intra- and inter-day precision was <9.3% and the accuracy was in the range 92.5-108.0%. The Armillarisin A concentration-time profile in human plasma was determined after an oral dose of a 40 mg tablet.

Preparation and evaluation of pranoprofen gel for percutaneous administration

The percutaneous delivery of nonsteroidal anti-inflammatory drug (NSAID) has the advantages of avoiding the hepatic first pass effect and delivering the drug to the inflammation site at a sustained, concentrated level over an extended period of time. Hydroxypropyl methylcellulose (HPMC) and poloxamer 407 were used in an attempt to develop new topical formulations of pranoprofen. The effects of the drug concentration (0.04, 0.08, 0.12, 0.16, and 0.20%) on the rate of drug release from HPMC-poloxamer 407 gels were examined using a synthetic cellulose membrane at 37+/-0.5 degrees C. The rate of drug permeation increased significantly with increasing drug concentration in the gels until the concentration reached 0.16%, and increased slightly thereafter. The effects of temperature on the rate of drug release from the 0.16% pranoprofen gels were evaluated at 32, 37, and 42 degrees C. The rate of drug release from the 0.16% pranoprofen gels increased with increasing temperature with activation energy (Ea) of 8.88 kcal/mol. Various penetration enhancers, such as nonionic surfactants and fatty acids, were incorporated in the gel formulation in an attempt to increase the level of drug permeation. Among the enhancers used, octanoic acid had the strongest enhancing effects with an enhancement factor of 3.09. The anti-inflammatory effect of the pranoprofen gel was evaluated using a rat paw-edema model. The 0.16% pranoprofen gel containing octanoic acid as an enhancer reduced the edema size by approximately 73% compared with that of the control group. These results highlight the feasibility of a topical gel formulation of pranoprofen containing an enhancer.

Nebivolol: a novel beta-blocker with nitric oxide-induced vasodilatation

Nebivolol is a novel beta₁-blocker with a greater degree of selectivity for beta₁-adrenergic receptors than other agents in this class and a nitric oxide (NO)-potentiating, vasodilatory effect that is unique among beta-blockers currently available to clinicians (nebivolol is approved in Europe and is currently under review in the US). A NO-potentiating agent such as nebivolol may have an important role in hypertensive populations with reduced endothelial function such as diabetics, African-Americans and those with vascular disease. Nebivolol is a racemic mixture with beta-blocker activity residing in the d-isomer; in contrast, l-nebivolol is far more potent in facilitating NO release. Nebivolol is unique among beta-blockers in that, at doses <10 mg, it does not inhibit the increase in heart rate normally seen with exercise. The efficacy of nebivolol has been tested successfully in clinical trials against other agents including other beta-blockers, angiotensin-converting enzyme-inhibitors and calcium channel antagonists in patients with hypertension, angina, and congestive heart failure. The tolerability of nebivolol has been shown to be superior to that of atenolol and metoprolol. In controlled clinical trials, nebivolol has a side effect profile that is similar to placebo, in particular as it relates to fatigue and sexual dysfunction. This article will review published clinical data regarding this cardioselective beta-blocker.

Single and multiple ascending dose studies of a novel tissue-selective oestrogen receptor modulator, CHF 4227, in healthy postmenopausal women

AIMS

We evaluated the tolerability, adverse events profile, pharmacokinetics, and pharmacodynamics of CHF 4227, a new selective oestrogen receptor modulator (SERM), in healthy postmenopausal women.

METHODS

Two phase I studies were conducted according to a double-bind, placebo-controlled design. Subjects were randomized to receive six single (5-400 mg) or five multiple oral doses of CHF 4227 for 28 days (5-100 mg).

RESULTS

No vaginal bleeding and no changes in either endometrial thickness or the placenta protein 14 marker were found after 4 weeks of treatment. The compound did not induce negative effects on the fibrinolytic system. After 28 days of treatment, CHF 4227 decreased both total and LDL cholesterol concentrations (maximum decreases from baseline of 17.4% (95% CI 7.0, 27.7) and 27.6% (95% CI 9.0, 46.3), respectively). Decreases in both serum and urinary type-I C-terminal collagen telopeptide were also observed producing maximum changes of 40.6% (95% CI 29.5, 51.7), and 41.7% (95% CI 20.3, 56.8), respectively. CHF4227 (5 and 10 mg) induced near maximal oestrogen-like effects on bone markers and serum lipids without causing hot flushes. The pharmacokinetics of CHF 4227 were characterized by a slow absorption, a long elimination half-life (31-42 h after single administration) and dose linearity with respect to C(max) and AUC up to 100 mg.

CONCLUSIONS

CHF 4227 is a well-tolerated SERM when administered once daily for 28 days. It is potentially active on bone resorption and serum lipids, without affecting the endometrium and without worsening hot flushes. CHF 4227 is a promising agent for the treatment of several conditions in postmenopausal women.

NIP-141, a multiple ion channel blocker, terminates aconitine-induced atrial fibrillation and prevents the rapid pacing-induced atrial effective refractory period shortening in dogs

AIMS

NIP-141 is a novel multiple ion channel blocker with atrial selective effects. In this study, we examined the effects of NIP-141 on aconitine-induced atrial fibrillation (AF) and rapid atrial pacing-induced atrial effective refractory period (ERP) shortening in dogs.

METHODS AND RESULTS

Aconitine AF was induced by the application of aconitine on the right appendage. NIP-141 (10 mg/kg) converted AF to sinus rhythm in 5 of 6 dogs. The Na(+) channel blockers disopyramide (1 mg/kg) and phenytoin (10 mg/kg) also terminated AF, but the I(Kr) blocker (d-sotalol; 4 mg/kg) and a Ca(2+) channel blocker (verapamil; 0.3 mg/kg) did not terminate AF in this model. To clarify the mechanism of AF termination, we examined the effects on ERP and conduction time, but NIP-141 (10 mg/kg) had no significant effects. In a short-term rapid atrial pacing model, NIP-141 (2.5 mg/kg/10 min, followed by 0.033 mg/kg/min) prevented atrial ERP shortening. We also found NIP-141 bound to Na(+) channel site 2 receptor and L-type Ca(2+) channel, but not to Na(+) channel site 1 receptor using radioligands binding assay.

CONCLUSION

NIP-141 terminated AF in aconitine-induced AF and prevented the atrial remodelling by short-term rapid pacing in dogs, possibly via the blocking of Na(+) and Ca(2+) channels.

Synergistic inhibition of breast cancer cell lines with a dual inhibitor of EGFR-HER-2/neu and a Bcl-2 inhibitor

The epidermal growth factor receptor (EGFR) (ErbB1) and HER-2/neu (ErbB2) are members of the ErbB family of receptor tyrosine kinases. These receptors are overexpressed in a variety of human tumors and overexpression generally correlates with poor prognosis and decreased survival. Lapatinib, a reversible inhibitor of both EGFR and HER-2/neu, has shown some success in achieving clinical responses in heavily pretreated advanced cancer patients. GW2974 is a reversible dual inhibitor similar to lapatinib, but GW2974 was not progressed to clinical trials due to pharmacokinetic issues. Bcl-2, an anti-apoptotic protein, is also overexpressed in a number of human tumors. Bcl-2 inhibitors induce apoptosis and sensitize cancer cells to other therapies. The purpose of this study was to assess the effects of combining ErbB and Bcl-2 inhibitors on the growth of human breast cancer cell lines. EGFR/HER-2/neu tyrosine kinase inhibitors (lapatinib and GW2974) were combined with Bcl-2 inhibitors (HA14-1 or GX15-070) and the anti-proliferative effects were determined by the MTT tetrazolium dye assay. Combinations were tested in MCF-7 human breast cancer cells, a HER-2/neu transfected MCF-7 cell line (MCF/18), and a tamoxifen-resistant MCF-7 cell line (MTR-3). A synergistic inhibitory effect was observed with the combination of inhibitors of EGFR-HER-2/neu (lapatinib or GW2974) and Bcl-2 (GX15-070 or HA14-1) on the growth of the MCF-7, MCF/18, and MTR-3 human breast cancer cell lines. This study suggests that simultaneously blocking the ErbB family of receptor tyrosine kinases and Bcl-2 family of proteins may be a benefit to breast cancer patients.

Acute hemodynamic effects of moderate doses of nebivolol versus metoprolol in patients with systolic heart failure

OBJECTIVES

To determine the acute hemodynamic effect of moderate doses of nebivolol (vasodilating beta1-selective blocker) vs. metoprolol tartrate (non-vasodilating beta1-selective blocker) in systolic heart failure (SHF).

MATERIAL AND METHODS

20 stable patients with SHF (left ventricular (LV) ejection fraction < or = 35%) underwent right heart catheterization. Once a reproducible baseline was obtained, patients were randomized to 5 mg nebivolol PO (n = 10) or metoprolol tartrate 50 mg PO (n = 10). Hemodynamic studies were repeated hourly for the first 4 hours and at 6 hours.

RESULTS

Both agents caused bradycardia. Nebivolol caused additionally a decrease in systemic vascular resistance (SVR) and no significant change in pulmonary capillary wedge pressure (PCWP), and cardiac output (CO). In contrast, metoprolol caused a deterioration of LV systolic function characterized by a decrease in cardiac output, and an increase in SVR and PCWP.

CONCLUSIONS

Treatment initiation with moderate doses of nebivolol is not associated with the adverse hemodynamic effects of metoprolol in patients with SHF. These findings suggest that a long up-titration period may not be necessary with nebivolol.

Tiliroside and gnaphaliin inhibit human low density lipoprotein oxidation

Two flavonoids, gnaphaliin and tiliroside, isolated from Helichrysum italicum, were studied in vitro for their capacity to inhibit Cu(2+)-induced human low density lipoprotein (LDL) and diluted plasma oxidation. LDL oxidation was monitored by conjugated diene, thiobarbituric acid-reactive substances (TBARS) formation and electrophoretic mobility on agarose gel. Gnaphaliin and tiliroside increased the lag-phase for diene conjugate production in a dose-dependent manner. The reduction of TBARS production confirmed the antioxidant activity of gnaphaliin and tiliroside with 50% inhibitory concentration (IC(50)) values of 8.0+/-3.9 microM and 7.0+/-2.6 microM respectively. Furthermore, the flavonoids negated the Cu(2+)-induced increase in electrophoretic mobility of LDL. Antioxidant activity of gnaphaliin and tiliroside was significantly different when diluted plasma was oxidised by adding 1 mM CuSO(4). Although both flavonoids again reduced the TBARS production, tiliroside showed higher activity than gnaphaliin (IC(50)=10.6+/-2.5 microM vs. IC(50)>50 microM). In conclusion, tiliroside and gnaphaliin are antioxidants against in vitro Cu(2+)-induced LDL oxidation in the same order of magnitude compared to that of the reference drug, probucol.

[Effect of sapropel mud on the parameters of oxidative stress and antioxidative defense in acute carbofos poisoning]

Sapropel was tested for its effect on the permeability of erythrocytic membranes and on the erythrocytic and serum levels of ceruloplasmin, malonic dialdehyde, and dienic conjugates in rats after acute poisoning by carbofos, a malathion insecticide. The increased processes of free radical oxidation during carbofos poisoning were suggested by the higher rates of chemiluminescence of erythrocytes and peripheral blood serum. No significant changes in the parameters of blood oxidative stress in the carbofos-poisoned animals during therapeutic-and-prophylactic use of sapropel indicate that the latter has antioxidative properties. Application of sapropel to normal animals exerted no effect of the studied parameters of oxidative stress. In acute carbofos poisoining, oral sapropel produced a pronounced antioxidative effect, which opens up new vistas for its practical application.

[Correction of primary hemostasis in patients suffering from arterial hypertension with metabolic syndrome]

The purpose of the study was to compare the effectiveness of normodipin and nebivolol for correction of platelet dysfunction in patients with metabolic syndrome. Normodipin was administered to 25 patients during three months in a dose of 10 mg a day. Nebivolol was administered to 21 patients in a dose of 5 mg a day. The dynamics of anthropometric indices, lipid blood spectrum, lipid peroxidation in the plasma and platelets, the antioxidant protection of the liquid part of blood and platelets, and aggregative platelet activity were evaluated. The results were processed using Student's criteria and system multi-factor analysis. The use of normodipin effected peroxidation syndrome more positively, and optimized platelet function to a greater extent that nebivolol. Long-term administration of normodipin is able to stabilize the achieved effect. To lower body weight in patients with arterial hypertension with metabolic syndrome normodipin application should be combined with non-drug treatment.

Comparing Beta-Blocking Effects of Bisoprolol, Carvedilol and Nebivolol

OBJECTIVE

Bisoprolol, carvedilol and nebivolol have been shown to be effective in the treatment of heart failure. However, the beta-blocking effects of these drugs have never been compared directly.

METHODS

Therefore, we performed a randomized, double-blind, placebo-controlled, cross-over trial in 16 healthy males. Subjects received 10 mg bisoprolol, 50 mg carvedilol, 10 mg nebivolol and placebo on the first morning followed by 5 mg bisoprolol once daily, 25 mg carvedilol twice daily, 5 mg nebivolol once daily and placebo for 1 week. Heart rate and blood pressure were measured at rest and exercise 3 and 24 h following intake of the first dose, and immediately before and 3 hours following intake of the last dose of each drug. In addition, effects of the drugs on nocturnal melatonin release were determined, and quality of life (QOL) was evaluated.

RESULTS

Heart rate at exercise was decreased at 3 h following intake of the first single dose of each drug by bisoprolol (-24%), carvedilol (-17%) and nebivolol (-15%), and at 24 h following intake of the respective last dose of each drug following 1 week of chronic administration by bisoprolol (-14%), carvedilol (12 h; -15%) and nebivolol (-13%) (p < 0.05 in all cases). Thus, trough-to-peak-ratios at long-term were as follows: Bisoprolol, 58%; carvedilol (12 h), 85%; nebivolol, 91%. Nocturnal melatonin release was decreased by bisoprolol (-44%, p < 0.05) whereas nebivolol and carvedilol had no effect. QOL with carvedilol was slightly but significantly lower than with the other drugs, whereas bisoprolol and nebivolol did not alter QOL.

CONCLUSIONS

These data show that peak beta-blocking effects of bisoprolol appear stronger than those of nebivolol and carvedilol. On the other hand, nebivolol exerts the highest trough-to-peak-ratio. However, beta-blocking effects of all the three drugs are similar at trough. Only bisoprolol but neither nebivolol nor carvedilol decreased nocturnal melatonin release, a feature which might cause sleep disturbances. Finally, only carvedilol slightly decreased QOL, whereas nebivolol and bisoprolol did not affect QOL. We conclude that different beta-blockers may exert clinically relevant different effects.

Anti-tumor effects of dehydroaltenusin, a specific inhibitor of mammalian DNA polymerase alpha

In the screening of selective inhibitors of eukaryotic DNA polymerases (pols), dehydroaltenusin was found to be an inhibitor of pol alpha from a fungus (Alternaria tennuis). We succeeded in chemically synthesizing dehydroaltenusin, and the compound inhibited only mammalian pol alpha with IC50 value of 0.5 microM, and did not influence the activities of other replicative pols such as pols delta and epsilon, but also showed no effect on pol alpha activity from another vertebrate, fish, or from a plant species. Dehydroaltenusin also had no influence on the other pols and DNA metabolic enzymes tested. The compound also inhibited the proliferation of human cancer cells with LD50 values of 38.0-44.4 microM. In an in vivo anti-tumor assay on nude mice bearing solid tumors of HeLa cells, dehydroaltenusin was shown to be a promising suppressor of solid tumors. Histopathological examination revealed that increased tumor necrosis and decreased mitotic index were apparently detected by the compound in vivo. Therefore, dehydroaltenusin could be of interest as not only a mammalian pol alpha-specific inhibitor, but also as a candidate drug for anti-cancer treatment.

Nebivolol improves coronary flow reserve in patients with idiopathic dilated cardiomyopathy

BACKGROUND

Impaired coronary flow reserve (CFR) is a significant predictor of poor prognosis in patients with idiopathic dilated cardiomyopathy (IDC). Nebivolol reduces mortality and morbidity in patients with heart failure and left ventricular dysfunction, including cases caused by IDC.

OBJECTIVE

To assess the effects of nebivolol on CFR in patients with IDC.

METHODS

CFR was measured in 21 clinically stable patients with IDC (mean (SD) ejection fraction 35.7 (6.2)) at baseline and after 1 month of treatment with nebivolol once daily. A control group of apparently healthy subjects who were matched for age and sex was used for comparison. Resting and hyperaemic coronary flows were measured using transthoracic second-harmonic Doppler echocardiography. None of the subjects had any systemic disease.

RESULTS

After 1 month of treatment, heart rate was reduced significantly (p<0.001). The blood pressure was decreased significantly (p<0.001). The left ventricular end-diastolic diameter and stroke volume were not changed significantly, but end-systolic diameter was decreased significantly (p<0.05). Resting rate-pressure product was lower after treatment with nebivolol, but dipyridamole-induced change was not influenced by the treatment. Nebivolol treatment reduced significantly coronary velocities at rest (p<0.02) and also caused a significant increase in coronary velocities after dipyridamole (p<0.02), leading to a greater CFR (2.02 (0.35) vs 2.61 (0.43), p<0.001). Nebivolol induced an absolute increase of 6% in the CFR in 17 of 21 patients (80.9%).

CONCLUSIONS

In patients with IDC, 1 month of treatment with nebivolol induces a marked increase in CFR.

Enhanced transdermal delivery of pranoprofen from the bioadhesive gels

Percutaneous delivery of NSAIDs has advantages of avoiding hepatic first pass effect and delivering the drug for extended period of time at a sustained, concentrated level at the inflammation site that mainly acts at the joint and the related regions. To develop the new topical formulations of pranoprofen that have suitable bioadhesion, the gel was formulated using hydroxypropyl methylcellulose (HPMC) and poloxamer 407. The effects of temperature on drug release was performed at 32 degrees C, 37 degrees C and 42 degrees C according to drug concentration of 0.04%, 0.08%, 0.12%, 0.16%, and 0.2% (w/w) using synthetic cellulose membrane at 37+/-0.5 degrees C. The increase of temperature showed the increased drug release. The activation energy (Ea), which were calculated from the slope of lop P versus 1000/T plots was 11.22 kcal/ mol for 0.04%, 10.79 kcal/mol for 0.08%, 10.41 kcal/mol for 0.12% and 8.88 kcal/mol for 0.16% loading dose from the pranoprofen gel. To increase the drug permeation, some kinds of penetration enhancers such as the ethylene glycols, the propylene glycols, the glycerides, the non-ionic surfactants and the fatty acids were incorporated in the gel formulation. Among the various enhancers used, propylene glycol mono laurate showed the highest enhancing effects with the enhancement factor of 2.74. The results of this study suggest that development of topical gel formulation of pranoprofen containing an enhancer is feasible.

Pharmacological activation of mGlu4 metabotropic glutamate receptors inhibits the growth of medulloblastomas

Moving from the evidence that activation of type 4 metabotropic glutamate (mGlu4) receptors inhibits proliferation and promotes differentiation of cerebellar granule cell neuroprogenitors, we examined the expression and function of mGlu4 receptors in medulloblastoma cells. mGlu4 receptors were expressed in 46 of 60 human medulloblastoma samples. Expression varied in relation to the histotype (nodular desmoplastic>classic>>large-cell anaplastic) and was inversely related to tumor severity, spreading, and recurrence. mGlu4 receptors were also found in D283med, D341med, and DAOY medulloblastoma cell lines, where receptor activation with the selective enhancer PHCCC inhibited adenylyl cyclase and the phosphatidylinositol-3-kinase pathway without affecting the mitogen-activated protein kinase, Sonic Hedgehog, and Wnt pathways. Interestingly, mGlu4 receptor activation reduced DNA synthesis and cell proliferation in all three cell lines. This effect was abrogated by the phosphatidylinositol-3-kinase inhibitor LY294002 [2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one]. In in vivo experiments, repeated subcutaneous injections of N-phenyl-7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxamide (PHCCC) reduced the growth of D283med and DAOY cell xenografts in nude mice. More remarkably, subcutaneous or intracranial injections of PHCCC during the first week of life prevented the development of medulloblastomas in mice lacking one Patched-1 allele and x-irradiated 1 d after birth. These data suggest that mGlu4 receptor enhancers are promising drugs for the treatment of medulloblastomas.