Long-term pretreatment with desethylamiodarone (DEA) or amiodarone (AMIO) protects against coronary artery occlusion induced ventricular arrhythmias in conscious rats.

The aim of this investigation was to compare the effectiveness of long-term pretreatment with amiodarone (AMIO) and its active metabolite desethylamiodarone (DEA) on arrhythmias induced by acute myocardial infarction in rats. Acute myocardial infarction was induced in conscious, male, Sprague-Dawley rats by pulling a previously inserted loose silk loop around the left main coronary artery. Long-term oral pretreatment with AMIO (30 or 100 mg·(kg body mass)(-1)·day(-1), loading dose 100 or 300 mg·kg(-1) for 3 days) or DEA (15 or 50 mg·kg(-1)·day(-1), loading dose 100 or 300 mg·kg(-1) for 3 days), was applied for 1 month before the coronary artery occlusion. Chronic oral treatment with DEA (50 mg·kg(-1)·day(-1)) resulted in a similar myocardial DEA concentration as chronic AMIO treatment (100 mg·kg(-1)·day(-1)) in rats (7.4 ± 0.7 µg·g(-1) and 8.9 ± 2.2 µg·g(-1)). Both pretreatments in the larger doses significantly improved the survival rate during the acute phase of experimental myocardial infarction (82% and 64% by AMIO and DEA, respectively, vs. 31% in controls). Our results demonstrate that chronic oral treatment with DEA resulted in similar cardiac tissue levels to that of chronic AMIO treatment, and offered an equivalent degree of antiarrhythmic effect against acute coronary artery ligation induced ventricular arrhythmias in conscious rats.

ATP-sensitive potassium channels modulate in vitro tocolytic effects of ß2-adrenergic receptor agonists on uterine muscle rings in rats in early but not in late pregnancy.

AIM: To investigate whether ATP-sensitive potassium (K(ATP)) channels modulate the tocolytic effect of ß2-adrenergic receptor (ß2-AR) agonists (ritodrine and salmeterol) in early-pregnant (day 6) and late-pregnant (day 22) rat uterus in vitro, in order to examine the relation between the K(ATP) channel sulphonylurea-binding regulatory subunit (SUR) expression and pharmacological reactivity of ß2-AR agonists. METHODS: The tocolytic effects of ritodrine and salmeterol (10(-10)-10(-5) M) on spontaneous rhythmic contractions were investigated cumulatively, alone, or in the presence of the K(ATP) channel blocker glibenclamide (10(-6) M) and the K(ATP) channel opener pinacidil (10(-9)-10(-7) M) after 5-min preincubation. RESULTS: ß2-AR agonist induced myometrial relaxation was inhibited by glibenclamide and enhanced by pinacidil on day 6, when SUR1 expression levels were high. Neither glibenclamide nor pinacidil mediated tocolytic effect was measured on day 22. CONCLUSION: Low expression of the K(ATP) channels at the end of gestation may facilitate enhanced excitability and contractility in the rat myometrium. The combination of a betamimetic and a K(ATP) channel opener will therefore not be of therapeutic relevance in the treatment of preterm delivery.

[Khat (Catha edulis): is it "coffee" or "cocaine"?]. / Khat (Catha edulis): "kávé" vagy "kokain"?

Regular consumption of khat's (Catha edulis) fresh leaves seriously affects the health, the social and economic life of the subject. Therefore, it is hazardous both to the individual and to the community. According to the latest reports, consumption of chat may exert some unknown and unreported gastrointestinal and hepatic effects. On the basis of studies performed by the authors, it seems that khat (cathinone) has no gastric or duodenal ulcerogenic effect. However, it does cause a significant enlargement of the hepatic mitochondria. In addition, a concern arose recently that the profit of illegal traffic of the plant may reach some illegal (terrorist) organisations. Therefore it seems that the so-called "khat-problem" needs further and more effective control.

[Ontogeny of sulphonylurea-binding regulatory subunits of K(ATP) channels in the pregnant rat myometrium]. / A K(ATP) csatorna szulfonilurea alegységeinek ontogenezise a terhes patkány miometriumban.

K(ATP) channels are composed of sulphonylurea receptors (SURs) and potassium inward rectifiers (Kir(6.x)) that assemble to form a large octameric channel. This study was designed to examine the expression and role of sulphonylurea-binding regulatory subunits 1 [SUR1 (ABCC8)] and 2 [SUR2 (ABCC9)] of the K(ATP) channels in the pregnant rat myometrium with particular regard to the contractility. RT-PCR and Western blot analysis were performed to detect the presence of SUR1 and SUR2. The SUR1 levels were markedly increased in the early stages of pregnancy. The highest level was detected on day 6 of pregnancy, while in the late stages the levels of SUR1 were significantly decreased. The SUR2 level remained unchanged throughout pregnancy. The SUR-non-selective diazoxide and the SUR2-selective pinacidil inhibited oxytocin-induced contractions. Glibenclamide, a K(ATP) channel blocker, antagonized both pinacidil and diazoxide-induced relaxations. It was established that SURs are responsible for pharmacological reactivity of K(ATP) channel openers. We conclude that, both SURs are involved in the K(ATP) channel in the pregnant rat myometrium. It may further be concluded that "pinacidil-like" K(ATP) channel openers may be of therapeutic relevance as tocolytic agents in the future.

[Investigation of uterus-relaxing effects of nifedipine in the presence of terbutaline and K(+)-channel blockers]. / Nifedipin miometrium relaxáló hatásának vizsgálata terbutalin és K(+)-csatorna gátlók jelenlétében in vitro.

UNLABELLED: Tocolysis is one of the greatest challenges in obstetrical practice. It is known that the calcium channel antagonists abolish the intracellular calcium ion transients and myometrial contraction. However there is a growing interest in experimental studies to use different tocolytic combination. The aims of the study were to investigate the effects of nifedipine on potassium chloride (KCl)-evoked rat uterine contractions on the last day of pregnancy (22) in vitro, and the alterations in the effects of nifedipine on combination with BK(Ca-channel blockers paxillin and tetraethyl ammonium chloride in late pregnancy in vitro. An other aim was to investigate the modification of the effect of nifedipine by terbutaline on the contraction of isolated rat and human myometrium. For human myometrial rings rhythmic contractions were evoked with oxytocin in an isolated organ bath. KCl-stimulated uterine contractions were inhibited concentration-dependently by nifedipine. In the presence of the potassium channel blockers, the action of nifedipine was not modified. Synergism was observed in the uterus-relaxing effect of nifedipine and terbutaline, though the extent of potentiation depended on the sequence of the administration of the two compounds. When terbutaline was added first in a single dose, the maximal inhibitory effect of nifedipine was lower. This decrease in the inhibition was suspended by a Ca(2+)-poor buffer, indicating the role of Ca2+ channel activating effect of terbutaline. However, in the isolated organ bath studies the BK(Ca) channel had no effect on the uterus relaxing effect of nifedipine in spite of literature. CONCLUSION: It is concluded that the combination of nifedipine and beta2-agonists should be considered for clinical use. However, the administration of terbutaline can not precede the administration of nifedipine.

[The effect of the ARC 239 on the myometrial and cervical action in the rat, in vitro]. / Az ARC 239 hatása a miometrium és a cervix muködésére patkányban, in vitro.

The premature labour is one of the major challenges in the clinical practice. Finding new agents and mechanisms in the control of uterine activity is the main objective of the last decade's experiments. One of the new targets is the alpha2-adrenoceptors (alpha2-AR). The purpose of this study was to determine the effect of the alpha2B/C-adrenoceptor blocker ARC 239 on the myometrial contractions and the cervical resistance on pregnant rats, in vitro. We identified the alpha2-adrenoceptor subtypes proteins both in the myometrial and the cervical samples. In isolated organ studies, the ARC 239 exerted a strong inhibitory effect on noradrenaline-stimulated contractions. The effect of ARC 239 on labour-induced myometrial samples was also convincing. In the stretching test, the cervical resistance was increased and decreased in by ARC 239 on pregnancy days 18 and 20, respectively. ARC 239 did not have effect on the 22-day pregnant cervical samples. These results were supported by the cAMP studies. We can conclude that, the alpha2B-adrenoceptors predominate and mediate contraction, while the alpha2A- and alpha2C-ARs decrease the contractile response to noradrenaline in 22-days-pregnant animals. In the pregnant cervix the alpha2-adrenoceptors can couple to both G(i)- and G()-proteins in the 18- and 20-day-pregnant samples, respectively, resulting in increase or decrease in the cervical resistance. Based on these facts we suggest that ARC 239 may open new perspective in the influence of premature labour.

An intraperitoneally administered pentapeptide protects against Abeta (1-42) induced neuronal excitation in vivo.

The underlying cause of Alzheimer's disease (AD) is thought to be the accumulation and aggregation of a misfolded protein, amyloid-beta (Abeta). A promising strategy against AD is the application of protective, peptide-based neuroprotective agents that selectively bind to Abeta. We recently described a pentapeptide, LPYFDa, which recognizes Abeta (1-42) and protects neurons against the toxic effects of aggregated Abeta (1-42) both in vitro and in vivo. Our previous work indicated that the in vivo ejection of fibrillar Abeta (1-42) into the hippocampal CA1 region resulted in a massive increase in the NMDA-evoked neuronal firing rate. Our current aim was to study whether intraperitoneally administered LPYFDa is capable of protecting against the synaptotoxic action of fibrillar Abeta (1-42) administered by iontophoresis. Our investigations of the in vivo biodistribution of tritium-labelled LPYFDa and single-unit electrophysiology revealed that LPYFDa readily crosses the blood-brain barrier, and protects the synapses against the excitatory action of fibrillar Abeta (1-42) in a relatively wide temporal window in rat. This pentapeptide may serve as a lead compound for the design of novel drug candidates for the prevention of AD.

[Thermoanalytical investigation of rat myometrium during gestation]. / Patkány myometrium termoanalitikai vizsgálata terhesség alatt.

The aim of our present study was the investigation of rat myometrium by means of differential scanning calorimetry as a function of gestational age. Some additional groups of animals were exposed to adjuvant arthritis as a model for generalized inflammation. In order to find a connection between calorimetrically determined parameters and motor activity isolated organ experiments were performed and spontaneous as well as KCl-stimulated contractility were recorded. Uterine rings from the 5th day of early pregnancy (days 3-6) exhibited a maximum motor activity. A close correlation was revealed between calorimetric enthalpy (deltaH value) and basal and stimulated contractility. The generalized inflammation increased the maximal contractions at all tested stages (non pregnant, days 14 and 21). As gestation progressed deltaH value increased in control rats but not in animals exposed to inflammation. Our results indicate that calorimetric technique is suitable for functional investigation of pregnancy-induced or disease-related changes of myometrial samples.

[Formulation of an oral solid dosage form containing human interferon-alpha]. / Humán interferon-alpha orális szilárd gyógyszerformába történo feldolgozása.

The main objective of this study was to process the human alpha-interferon for the solid dosage form. The first step was the preparation of the intermediate product for the tablet making. Fluid bed apparatus with top spray method was applied for the layering of powdered cellulose with human alpha-interferon solutions. The intermediate product was compressed into tablet and an enteric solvent coating of the tablets was made in a fluid bed apparatus with Wurster method. The physical parameters were detected. These fitted the Ph. Eur. and the mechanical properties of the tablets were appropriate for coating in fluid bed apparatus. The tablets agree with the requirements of Ph. Eur. and the active agent was not dissolved in gastric juice. An animal test was also performed. The human alpha-interferon in the blood of the animals was detected with ELISA method. The human alpha-interferon specific kit was used. The active ingredient dissolved from the tablets was absorbed from the ileum. The solid dosage form containing human alpha-interferon was prepared; this can make oral application of human alpha-interferon possible.

Fermented wheat germ extract (avemar) inhibits adjuvant arthritis.

Anti-inflammatory efficacy of the fermented wheat germ extract (FWGE, Avemar) in the rat adjuvant arthritis (AA) model was examined. To Wistar rats with AA, different doses of FWGE and anti-inflammatory drugs (indomethacin, dexamethasone) as monotherapies were administered and FWGE and either diclofenac or dexamethasone were also given in combination. Besides plethysmographies of the paws, histological investigations of synovial tissues were also performed along with detection of CD4+ and CD8+ T lymphocytes. Gene expressions of COX-1 and 2 were determined by real-time polymerase chain reaction (PCR). FWGE monotherapy significantly inhibited the development of the secondary (immune-mediated) response in AA, and dexamethasone and indomethacin exerted inhibitory effects in a degree comparable to that of FWGE. Histological analysis of the affected joints confirmed the results. FWGE inhibited COX-1 and -2, while indomethacin enhanced COX-2 gene expressions. FWGE had an additive interaction with diclofenac. It is concluded that FWGE has significant anti-inflammatory efficacy confirmed by plethysmography, histology, and real-time PCR.

Analysis of the role of central and peripheral alpha2-adrenoceptor subtypes in gastric mucosal defense in the rat.

The present study confirmed our previous assumption on the crucial role of central alpha2B-like adrenoceptor subtype in gastric mucosal defense. It was found that beside clonidine, rilmenidine, an alpha2/imidazoline receptor agonist and ST-91, an alpha2B-adrenoceptor preferring agonist inhibited the mucosal lesions induced by ethanol given intracerebroventricularly (i.c.v.). The ED50 values for clonidine, rilmenidine and ST-91 are 0.2, 0.01 and 16 nmol/rat i.c.v., respectively. The effect was reversed by the intracerebroventricularly injected alpha2B/2C-adrenoceptor antagonists prazosin and ARC-239, indicating the potential involvement of central alpha2B/2C-adrenoceptor subtype in the protective action. The gastroprotective effect of adrenoceptor stimulants was reversed by bilateral cervical vagotomy, suggesting that vagal nerve is likely to convey the central action to the periphery. In gastric mucosa both nitric oxide and prostaglandins may mediate the centrally-induced effect, since both indomethacin and N(G)-nitro-L-arginine reversed the protective effect of alpha2-adrenergic stimulants. Though expression of mRNA of alpha2B-, as well as alpha2A- and alpha2C-adrenoceptor subtypes was demonstrated in gastric mucosa of the rat, the hydrophilic ST-91, given peripherally (orally, subcutaneously), failed to exert mucosal protection, in contrast with clonidine and rilmenidine which were also effective. Consequently, while peripheral alpha2B-adrenoceptors are not likely to be involved in gastric mucosal protection, activation of central alpha2B-like adrenoceptor subtype may initiate a chain of events, which result in a vagal dependent gastroprotective action.

3D QSAR models for alpha2a-adrenoceptor agonists.

Three-dimensional structure-activity relationship studies of alpha2a-adrenoceptor agonists were carried out by Distance Comparison (DISCOthech) and Comparative Molecular Field Analysis (CoMFA) methods to define the pharmacophore and a quantitative model, respectively, of this class of compounds. The statistical validation of the CoMFA model indicates its high predictive performance for binding affinities of new alpha2a-adrenoceptor agonists.

Diterpenoids and flavonoids from the fruits of Vitex agnus-castus and antioxidant activity of the fruit extracts and their constituents.

From the n-hexane fraction of the fruits of Vitex agnus-castus, two labdane-type diterpenes, vitetrifolin B and C, were isolated by means of multiple chromatographic separations, together with the previously identified rotundifuran, vitexilactone and the sesquiterpene spathulenol. From the EtOAc fraction, eupatorin was identified for the first time, besides the known casticin, penduletin, vitexin and orientin. The n-hexane, EtOAc and MeOH-H(2)O fractions of the MeOH extract of Agni-casti fructus were subjected to in vitro antioxidant assays. The EtOAc extract displayed a significant concentration-dependent effect when tested by 1,1-diphenyl-2-picrylhydrasyl (DPPH) free radical assay (IC(50) = 68 microg/mL) and against the autooxidation of a standard rat brain homogenate (IC(50) = 14 microg/mL). The MeOH-H(2)O fraction was less active with 3643 microg/mL (DPPH test) and IC(50) = 125 microg/mL (rat brain homogenate), while the n-hexane phase proved to be inactive. The main flavonoid constituents of the EtOAc extract, casticin, vitexin and orientin were assayed for antioxidant activity and found that only casticin possesses a marked lipid peroxidation inhibitory effect (IC(50) = 0.049 mm) compared with that of the positive control ascorbic acid (IC(50) = 0.703 mm).

Phenanthrenes and a dihydrophenanthrene from Tamus communis and their cytotoxic activity.

From the petroleum ether extract of the rhizomes of Tamus communis, the 7-hydroxy-2,3,4,8-tetramethoxyphenanthrene (1) was isolated, together with the known 2,3,4-trimethoxy-7,8-methylenedioxyphenanthrene (2), 3-hydroxy-2,4,-dimethoxy-7,8-methylenedioxyphenanthrene (3), 2-hydroxy-3,5,7-trimethoxyphenanthrene (4) and 2-hydroxy-3,5,7-trimethoxy-9,10-dihydrophenanthrene (5), through cytotoxic assay guidance. The structures were determined by means of HREIMS, (1)H NMR, JMOD and NOESY experiments. The cytotoxic effects of the isolated compounds were tested on cervix adenocarcinoma (HeLa) cells, with the MTT assay. The results demonstrated that, with the exception of 2, all these compounds displayed pronounced cytotoxic activity; especially 1 and 3 exhibited significant cell growth inhibitory effects, with IC(50)=8.52+/-0.70 and 3.64+/-0.12 microM, respectively.

[In vitro methods suitable for the prediction of drug and ABC transporter, especially ABCG2 interactions]. / ABC transzporterek-különös tekintettel az ABCG2-re--és gyógyszerjelölt molekulák kölcsönhatásának predikciójára alkalmas in vitro módszerek.

ABCG2, a transporter of the ATP-binding cassette family, is known to play a prominent role in the absorption, distribution, metabolism, and excretion of xenobiotics. Drug-transporter interactions are commonly screened by in vitro systems using transfected insect and/or human cell lines.

Cytotoxic phenanthrenes from the rhizomes of Tamus communis.

From the fresh rhizomes of Tamus communis five phenanthrenes (1 - 5) were isolated under the guidance of cytotoxic assays in HeLa cells. The compounds were obtained from the highly active CHCl (3) fraction of the MeOH extract by using multistep chromatographic purifications, including VLC, preparative TLC, HPLC and gel filtration. The compounds were identified by means of EI-mass, UV and NMR spectroscopy as 7-hydroxy-2,3,4-trimethoxyphenanthrene (1), 2,7-dihydroxy-3,4-dimethoxyphenanthrene (nudol) (2), 2,7-dihydroxy-3,4,8-trimethoxyphenanthrene (3), 3,7-dihydroxy-2,4,8-trimethoxyphenanthrene (confusarin) (4), and 3,7-dihydroxy-2,4-dimethoxyphenanthrene (5). Compound 1 is a new natural product, and 2 - 4 were isolated for the first time from T. communis. In the cytotoxic assays, compounds 1 - 3 and 5 significantly inhibited the growth of HeLa cells (IC (50) = 0.97 - 20.18 microM). Compound 3, with an IC (50) value of 0.97 microM, is of special interest because of its high activity.

The role of androgen receptors in the dynamic process of prostate cancer: their analytical determination in biopsy material.

Under normal conditions, androgen receptors function via ligand binding and other coactivators in prostate cancer cells. The effects of the currently applied therapy are achieved through inhibition of the formation of the testosterone-receptor complex. With the advance of research at a cellular level, it is now known that tumorigenesis is much more complicated, and that tumour cell growth regulated by androgens is a complex process. The aim of our work was to utilize literature data in a search for a correlation between the number of androgen receptors and the clinical course of the disease. Transperineal ultrasound-guided biopsies were performed on 82 (otherwise unselected) patients with suspected prostate cancer, and the numbers of androgen receptors in the tissue samples were determined by a receptor-analytical method. Prostate cancer was confirmed in 43 cases. Rebiopsy was scheduled for 1 year later. We were able to carry out repeated biopsies in 18 cases, and to determine the number of receptors by the earlier method. The patients were followed clinically, and the efficacy of their medication was measured via improvement in their general condition and study of the prostate-specific antigen level. The investigation demonstrated that determination of the number of receptors itself is not of prognostic value, but it does provide information to supplement the other parameters relating to the state.

Diterpenes from the aerial parts of Salvia candelabrum and their protective effects against lipid peroxidation.

A methanolic extract of the aerial parts of Salvia candelabrum was subjected to multiple chromatographic separation under the guidance of anti-lipid peroxidation assay. From the most active fractions seven abietane and seco-abietane diterpenes were isolated by preparative TLC purification. Besides candesalvoquinone, candelabroquinone, 12- O-methylcandesalvone B, candesalvone B methyl ester and candelabrone (all reported earlier), the known candesalvone B and the new candesalvolactone were identified. The structures were established by means of mass spectroscopy and advanced 2D NMR methods. All the identified compounds were evaluated for antioxidant activity in enzyme-dependent (IC (50) values 3.49 - 10.42 microM) and enzyme-independent (IC (50) values 1.40 - 13.40 microM) systems of lipid peroxidation. All compounds displayed marked concentration-dependent effects in both tests as compared with those of authentic ascorbic, rosmarinic and caffeic acids. The differences in antioxidant capacities observed in the enzyme-independent system allowed conclusions concerning structure-activity relationships.