Macitentan significantly reduced morbidity and mortality among patients with pulmonary arterial hypertension in this event-driven study. (Funded by Actelion Pharmaceuticals; SERAPHIN ClinicalTrials.gov number, NCT00660179.).

BACKGROUND: In a phase 2 trial, selexipag, an oral selective IP prostacyclin-receptor agonist, was shown to be beneficial in the treatment of pulmonary arterial hypertension. METHODS: In this event-driven, phase 3, randomized, double-blind, placebo-controlled trial, we randomly assigned 1156 patients with pulmonary arterial hypertension to receive placebo or selexipag in individualized doses (maximum dose, 1600 μg twice daily). Patients were eligible for enrollment if they were not receiving treatment for pulmonary arterial hypertension or if they were receiving a stable dose of an endothelin-receptor antagonist, a phosphodiesterase type 5 inhibitor, or both. The primary end point was a composite of death from any cause or a complication related to pulmonary arterial hypertension up to the end of the treatment period (defined for each patient as 7 days after the date of the last intake of selexipag or placebo). RESULTS: A primary end-point event occurred in 397 patients--41.6% of those in the placebo group and 27.0% of those in the selexipag group (hazard ratio in the selexipag group as compared with the placebo group, 0.60; 99% confidence interval, 0.46 to 0.78; P<0.001). Disease progression and hospitalization accounted for 81.9% of the events. The effect of selexipag with respect to the primary end point was similar in the subgroup of patients who were not receiving treatment for the disease at baseline and in the subgroup of patients who were already receiving treatment at baseline (including those who were receiving a combination of two therapies). By the end of the study, 105 patients in the placebo group and 100 patients in the selexipag group had died from any cause. Overall, 7.1% of patients in the placebo group and 14.3% of patients in the selexipag group discontinued their assigned regimen prematurely because of adverse events. The most common adverse events in the selexipag group were consistent with the known side effects of prostacyclin, including headache, diarrhea, nausea, and jaw pain. CONCLUSIONS: Among patients with pulmonary arterial hypertension, the risk of the primary composite end point of death or a complication related to pulmonary arterial hypertension was significantly lower with selexipag than with placebo. There was no significant difference in mortality between the two study groups. (Funded by Actelion Pharmaceuticals; GRIPHON ClinicalTrials.gov number, NCT01106014.).

Laila Hübbert vid avdelningen för kardiovaskulär medicin samt Kardiologiska kliniken US, tillhör "GRIPHON Investigators".

The effect of ultrasound (US) (26.4 kHz, 26 W/cm2) on the activation process of a mixture of chymotrypsinogen and trypsinogen was studied. US led to a significant decrease in proteolytic activity, as well as inhibition of the activation process in general. It was shown that inhibition of proteinase activity under US influence was a consequence of inhibition of chymotrypsinogen-chymotrypsin transformation and the complete proteolytic trypsin degradation in the proenzymes mixture.

Kinetics of inactivation of horseradish peroxidase (HP) induced by low-frequency ultrasonic (US) treatment (27 kHz) with the specific power of 60 W/cm2 were studied in phosphate (pH 7.4) and acetate (pH 5.2) buffers within the temperature range of 36.0 to 50.0 degrees C and characterized by effective first-order rate constants of US inactivation k(in)(us) in min(-1). Values of k(in)(us) depend on the specific ultrasonic power within the range of 20-60 W/cm2, on the concentration of HP, and on pH and temperature of the solutions. The activation energy of US inactivation of HP is 9.4 kcal/mole. Scavengers of HO* radicals, mannitol and dimethylformamide, significantly inhibit the US inactivation of HP at 36.0 degrees C, whereas micromolar concentrations of polydisulfide of gallic acid (poly(DSG)) and of poly(2-aminodisulfide-4-nitrophenol) (poly(ADSNP)) virtually completely suppress the US inactivation of peroxidase at the ultrasonic power of 60 W/cm2 on the sonication of the enzyme solutions for more than 1 h at pH 5.2. Various complexes of poly(DSG) with human serum albumin effectively protect HP against the US inactivation in phosphate buffer (pH 7.4). The findings unambiguously confirm a free radical mechanism of the US inactivation of HP in aqueous solutions. Polydisulfides of substituted phenols are very effective protectors of peroxidase against inactivation caused by US cavitation.

BackgroundPharmacological thrombolysis with streptokinase, urokinase or tissue activator of plasminogen (t-PA), and mechanical interventions are frequently used in the treatment of both arterial and venous thrombotic diseases. It has been previously reported that application of ultrasound as an adjunct to thrombolytic therapy offers unique potential to improve effectiveness. However, little is known about effects of the ultrasound on proteins of blood coagulation and fibrinolysis. Here, we investigated the effects of the ultrasound on fibrinogen on processes of coagulation and fibrinogenolysis in an in vitro system.ResultsOur study demonstrated that low frequency high intensity pulse ultrasound (25.1 kHz, 48.4 W/cm2, duty 50%) induced denaturation of plasminogen and t-PA and fibrinogen aggregates formation in vitro. The aggregates were characterized by the loss of clotting ability and a greater rate of plasminolysis than native fibrinogen. We investigated the effect of the ultrasound on individual proteins. In case of plasminogen and t-PA, ultrasound led to a decrease of the fibrinogenolysis rate, while it increased the fibrinogenolysis rate in case of fibrinogen. It has been shown that upon ultrasound treatment of mixture fibrinogen or fibrin with plasminogen, t-PA, or both, the rate of proteolytic digestion of fibrin(ogen) increases too. It has been shown that summary effect on the fibrin(ogen) proteolytic degradation under the conditions for combined ultrasound treatment is determined exclusively by effect on fibrin(ogen).ConclusionsThe data presented here suggest that among proteins of fibrinolytic systems, the fibrinogen is one of the most sensitive proteins to the action of ultrasound. It has been shown in vitro that ultrasound induced fibrinogen aggregates formation, characterized by the loss of clotting ability and a greater rate of plasminolysis than native fibrinogen in different model systems and under different mode of ultrasound treatment. Under ultrasound treatment of plasminogen and/or t-PA in the presence of fibrin(ogen) the stabilizing effect fibrin(ogen) on given proteins was shown. On the other hand, an increase in the rate of fibrin(ogen) lysis was observed due to both the change in the substrate structure and promoting of the protein-protein complexes formation.