In vitro activity of essential oils of free and nanostructured Melaleuca alternifolia and of terpinen-4-ol on eggs and larvae of Haemonchus contortus.

Haemonchus contortus is one of the major gastrointestinal nematodes responsible for significant economic and production losses of sheep. Diseases caused by this species lack effective anthelmintic products, and the search for new compounds to replace synthetic anthelmintics has been extensive. The present investigation assesses the in vitro activity of the essential oil of melaleuca (Melaleuca alternifolia), both free (TTO) and nanostructured (nanoTTO), and terpinen-4-ol (terp-4-ol) on eggs and larvae of H. contortus. Tests of egg hatching (EHT) and inhibition of larval migration (LMIT) were used to assess the in vitro efficacy of TTO, nanoTTO and terp-4-ol. Using EHT, at a concentration of 3.5 mg/ml, 100% inhibition occurred using TTO and terp-4-ol, with LC50 values of 0.43 and 0.63 mg/ml, and LC90 values of 1.75 mg/ml and 3.12 mg/ml, respectively. NanoTTO had lower activity, with 82.6% inhibition at the same concentration. Using LMIT, TTO and nanoTTO had a similar activity with 88.0% and 84.8% inhibition, respectively, at a concentration of 56 mg/ml. Terp-4-ol had a greater effect on larvae, with 85.7% inhibition at a concentration of 56 mg/ml and 82.4% at 3.5 mg/ml, demonstrating high activity at the lowest concentration tested. Therefore, the results indicate that all substances tested showed ovicidal and larvicidal activity against H. contortus. TTO, terp-4-ol and, mainly, nanoTTO may be targeted in in vivo studies, besides being a promising line of research into the control and treatment of veterinary important helminths.

Radionuclide assessment of cardiac performance in cystic fibrosis. Reproducibility and effect of theophylline on cardiac function.

A study was designed to evaluate the reproducibility of right and left ventricular ejection fraction measurements (RVEF, LVEF) by equilibrium radionuclide angiography in cystic fibrosis (CF) and to determine the effect of the acute administration of aminophylline on RVEF and LVEF in this disease. Both RVEF and LVEF were measured at rest and during incremental supine bicycle exercise by equilibrium radionuclide angiography in 18 patients with CF. In 9 of these patients, radionuclide studies were repeated after an infusion of aminophylline (9 mg/kg), whereas the remaining patients had radionuclide studies repeated after a placebo infusion. No significant increase in mean RVEF or LVEF values either at rest or at peak exercise was seen after aminophylline infusion. In the patients who underwent sequential radionuclide studies without intervening active drug intervention, the mean (+/- standard deviation) variability in RVEF and LVEF measurements between the 2 studies was 2.6 +/- 2% and 3.6 +/- 2.9%, respectively. We conclude that (1) equilibrium radionuclide angiography is a reasonably reproducible technique for serial assessment of biventricular function at rest and during exercise in CF, and that (2) the acute administration of aminophylline does not augment cardiac function either at rest or during exercise in this disease.