[THE IMPORTANCE OF ANTICOAGULANT THERAPY IN PATIENTS WITH ARTIAL FIBRILLATION IN STROKE PREVENTION--SUMMARY OF INTERNATIONAL DATA AND NOVEL THERAPEUTIC MODALITIES]. / A PITVARFIBRILLÁLÓ BETEGEK ANTIKOAGULÁNS KEZELÉSÉNEK JELENTOSÉGE A STROKE MEGELOZÉSÉBEN--A NEMZETKÖZI ADATOK ÉS AZ ÚJABB TERÁPIÁS LEHETOSÉGEK ÁTTEKINTÉSE.

The most common cardiogenic cause of ischaemic stroke is atrial fibrillation which increases the probability of stroke five-fold and doubles case fatality. Based on international data the incidence of atrial fibrillation is approx. 2% however this rapidly increases with age. The necessity of using oral anticoagulants in the prevention of non-valvular atrial fibrillation related stroke is decided based on estimated stroke risk. The CHADS2 and the more predictive CHA2DS2-VASc scales are used for this purpose while the bleeding risk of patients treated with anticoagulant may be estimated by the HAS-BLED scoring scale. For decades oral anticoagulation meant using vitamin-K antagonists. Based on international data we can see that rate of anticoagulation is unacceptably low, furthermore most of the anticoagulated patients aren't within the therapeutic range of INR (INR: 2-3). A lot of disadvantages of vitamin-K antagonists are known (e.g. food-drug interaction, need for regular coagulation monitoring, increased risk of bleeding), therefore compounds with new therapeutic target have been developed. The novel oral anticoagulants (NOAC) can be divided in two major subgroups: direct thrombin inhibitors (dabigatran etexilate) and Xa-factor inhibitors (rivaroxaban, apixaban, edoxaban). These products are administered in fix doses, they less frequently interact with other medications or food, and regular coagulation monitoring is not needed when using these drugs. Moreover several studies have shown that they are at least as effective in the prevention of ischaemic stroke than the vitamin-K antagonists, with no more haemorrhagic complications.

Protective effect of Cassia fistula fruit extract on bromobenzene-induced nephrotoxicity in mice.

The efficacy of a crude hydro-alcoholic extract of Cassia fistula (golden shower tree) fruit to protect the kidney against bromobenzene-induced toxicity was studied. Negative control mice received normal saline; positive control mice were given 460 mg/kg of bromobenzene; Cassia fistula treated mice received 200, 400, 600 and 800 mg/kg of Cassia fistula fruit extract followed by 460 mg/kg bromobenzene (daily by oral gavage for 10 days). On the 11th day, the mice were sacrificed, blood samples were obtained to assess blood urea nitrogen (BUN) and creatinine levels, and kidneys were removed for histological examination. We found that bromobenzene induced significant nephrotoxicity reflected by an increase in levels of BUN and creatinine that was dose dependently prevented by the Cassia fistula fruit extract. The nephroprotective effect of the Cassia fistula fruit extract was confirmed by the histological examination of the kidneys. To the best of our knowledge, this is the first study to demonstrate the protective effect of Cassia fistula in nephrotoxicity.

Resveratrol: a multifunctional cytoprotective molecule.

Several recent studies have shown the protective effects of resveratrol in various experimental conditions and pathological animal models. Clinical studies also indicate the beneficial effects of resveratrol in different human diseases. Resveratrol produces a cascade against of events from the initial death-provoking signal, DNA fragmentation, and cell death. Researchers recognized the beneficial effect of resveratrol, as an important component, of the overall injury that occurs in various disorders such as oxidative stress, myocardial injury, anticancer activity, antidiabetic activity, and antihypercholesterolemic effects. Many mechanisms have been proposed for the initiation of protective effects of resveratrol in various pathological events, and considerable evidence exists to indicate that many mediators are involved in the resveratrol-induced protection. The present review focuses on the history, and the beneficial effects and mechanisms of resveratrol in oxidative stress, myocardial injury, anticancer-, antidiabetic- and antihypercholesterolemic activities, and discusses those therapeutic tools, which warrant becoming clinically important.

Modulation of adenosine-induced responses in the guinea-pig trachea during long-term caffeine treatment: possible role of epithelium.

The responses to adenosine were studied on isolated, methacholine-precontracted tracheal strips of guinea pigs in the course of long-term caffeine or solvent treatment. Guinea pigs were fed caffeine for 10 weeks (average serum caffeine concentration: 39.1 +/- 3.9 microM). In epithelium-intact tracheal preparations (EITPs), sensititization to adenosine-induced relaxation (AIR) developed. It attained a maximum in week 1 of caffeine treatment, and then its level diminished and disappeared completely by weeks 4 - 6. In epithelium-denuded tracheal preparations (EDTPs), an increase in the sensitivity to adenosine was observed from week 1 to week 10 (a 4 - 6-fold reduction in EC50). Use of a coaxial bioassay system confirmed the role of epithelium in this process. The enhancement of the AIR of the EITPs was not modified by inhibitors of cyclooxygenase and lipoxygenase. Following depletion of the neuropeptides by acute capsaicin pretreatment, the AIR of the EITPs was strongly enhanced after caffeine treatment for 6 weeks. In chronically caffeine-treated EITPs, the inhibition of neutral endopeptidase led to dramatic reduction of the AIR. On the basis of the results by inhibiting nitric oxide synthase, it can be supposed that nitric oxide released from EITPs of long-lasting caffeine-treated animals operated as a constrictor agent. Our results show that chronic caffeine treatment gives rise to an initial sensitization to adenosine of the EITPs, this being followed by the development of a specific adaptive process in the epithelial cells, which counterbalances the increased tracheal sensitivity to adenosine.

Pre-clinical methods for the determination of insulin sensitivity.

We compared the hyperinsulinaemic euglycaemic glucose clamping (HEGC) procedure and the rapid insulin sensitivity test (RIST) to characterize insulin sensitivity in anaesthetized rats. The changes in insulin sensitivity were then supplemented with the direct measurement of insulin-stimulated glucose uptake using tissue accumulation of radioactive 2-deoxyglucose in skeletal muscle samples obtained from animals undergone either procedure. Studies of the recently described endogenous insulin sensitizer mechanism termed hepatic insulin sensitizing (HISS) mechanism, by the two methods yielded data for evaluation. The HISS mechanism is defined as an increase in tissue insulin sensitivity in response to post-prandial hepatic release of an undefined substance through a nitrergic pathway. For the HEGC method, insulin was infused to attain a stable plasma insulin immunoreactivity of 100 microU/ml determined by radioimmunoassay, whereas with the RIST method the HISS mechanism was activated by a 50 mg/kg i.v. insulin bolus. Euglycaemia was kept constant by means of glucose infusion. With the HEGC and the RIST methods, insulin sensitivity was defined as the average rate of glucose infusion and the amount of glucose/kg body weight/40 min (RIST index) infused to maintain euglycaemia and preinvestigation blood glucose level, respectively. During HEGC 16+/-4.2 mg/kg/min glucose was able to maintain euglycaemia, which decreased to 8+/-2.9 (p<0.05) after administration of 10 mg/kg NG-nitro-L-arginine methyl ester (L-NAME) (i.p.), a NO synthase inhibitor. Conversely, the RIST index decreased by 55+/-6.9% (p<0.05) after L-NAME. Similarly, 2-deoxyglucose uptake by the gastrocnemius muscle was decreased by 49.9+/-5.8 (p<0.05) and 52.3+/-7.4% (p<0.05) with the HEGC and the RIST methods, respectively. The results show that both the HEGC and the RIST methods supplemented with tissue radioactive 2-deoxyglucose uptake determinations are appropriate methods to characterize the alteration of insulin sensitivity in context of the HISS mechanism.