Patricio Torres

Chapter 1 Natural compounds as antioxidant and molting inhibitors can play a role as a model for search of new botanical pesticides

Publisher Summary There is a widespread effort to find new pesticides, and it is currently focused on natural compounds, such as flavonoids, coumarins, terpenoids, and phenolics from diverse botanical families from arid and semi-arid lands of Mexico and Americas. Additional experimental work has been carried out with natural products that are potential models for defensive substances against insect and fungal predators and as enzyme inhibitors, such as tyrosinase or acetylcholinesterase (AChE). The increasing interest in the possible application of secondary metabolites for pest management has directed the investigation toward the search for new sources of biologically active natural products with new mode, sites, and mechanisms of action. These characteristics may enhance their value as commercial pesticides. This chapter presents a review of extracts and bioactive compounds isolated by one study group from selected endemic botanical species and their antioxidant and biological activities. The chapter describes antifeedant activities shown by assayed compounds—that is, insecticidal or insect growth regulatory (IGR) activities and their activities on some enzymes.

Experimental flail chest : Ventilatory function with fixation of flail segment in internal and external position

UNLABELLED The effect on ventilatory function of fixation of a flail segment in internal (FIP) and external (FEP) position and oxygen administration was studied in an experimental flail chest with pleural indemnity. Variations of tidal volume (TV), respiratory rate (RR), minute volume (MV), and arterial blood gases are reported. These parameters were measured in nine dogs in control and flail conditions (FC). The effect of FIP, FEP, and oxygen administration were studied. RESULTS Significant differences were found: TV decreased from control values to FC and from FC to FIP, but increased from FC to FEP. RR values increased from control to FC and from FC to FIP, but decreased from FC to FEP. MV values decreased from FC to FEP. TV, RR, and MV were not changed under oxygen administration. Hypoxemia or hypercapnia were not observed. It was concluded that FIP is deleterious for respiratory mechanics, whereas FEP improves ventilatory parameters.

COMPETITIVE EFFECTS OF THE ALIEN INVASIVE CENTAUREA SOLSTITIALISL. ON TWO CHILEAN BACCHARIS SPECIES AT DIFFERENT LIFE-CYCLE STAGES

Varios estudios han revelado una variedad de mecanismos de invasion en las plantas aloctonas. Sin embargo, aun se conoce poco sobre como tales mecanismos y sus efectos asociados cambian a traves de diferentes estados del ciclo vida. En este estudio evaluamos, bajo condiciones controladas, el resultado de las interacciones competitivas entre la especie invasora Centaurea solstitialis L. (Asteraceae) y dos especies pioneras nativas del matorral chileno; Baccharis linearis (Ruiz et Pav.) Pers. y B. paniculata DC (Asteraceae). Estas interacciones fueron evaluadas combinando diferentes estados del ciclo de vida: semilla-semilla, planta-semilla y planta-planta. La germinacion de C. solstitialis fue explosiva, siendo mucho mas rapida que la de las especies nativas. La presencia de C. solstitialis (plantas o semillas) no disminuyo la germinacion de las especies nativas de Baccharis. Sin embargo, la presencia de plantas establecidas de C. solstitialis disminuyo significativamente la biomasa de las plantas de Baccharis. Entonces, el efecto de C. solstitialis sobre las especies de Baccharis vario en funcion del estado del ciclo de vida en el cual las interacciones ocurrieron. En el matorral chileno, la emergencia temprana y explosiva de C. solstitialis podria ser un importante mecanismo de invasion, ya que aquellas plantas prontamente establecidas podrian desplazar competitivamente a las plantulas de Baccharis que emergen mas tarde. La enorme abundancia de C. solstitialis en algunas zonas de matorral sugiere que el establecimiento de plantulas de estas dos especies pioneras podria estar siendo limitado.

Causes of increasing pericardial pressure in experimental cardiac tamponade induced by ventricular perforation.

It has been shown that the intravenous infusion of saline solution in a dog with stabilized cardiac tamponade produced an increase in pericardial pressure. To demonstrate that this pressure increase is the result of bleeding into the pericardial sac, an experimental study was conducted, consisting of the injection of red cells marked with 51Cr during the intravenous infusion of saline solution in dogs with and without progressive tamponade. The results showed that in the dogs without progressive tamponade, both the pericardial pressure and the red cell count in the pericardial cavity remained stable during the infusion of saline solution, whereas in dogs with progressive tamponade, the numbers of marked cells and the pericardial pressure increased significantly, following a similar pattern.

Wavelet and Fourier analysis of ventricular and main arteries pulsations in anesthetized dogs

The purpose of this study was to characterize time-frequency behavior using the Continuous Wavelet Transform (CWT) and Fast Fourier Transform (FFT) to analyze ventricular and arterial pressure signals from anesthetized mongrel dogs. Both ventricular and arterial pressure pulsations were recorded using catheter-tip manometers and the CWT was applied to these signals to obtain module coefficients, associated contours, and the 3-D representation of these modules. FFT was applied to obtain the Fourier spectrum. The mathematical analysis of the cardiovascular pressure pulsations permitted the identification of the evolution of the frequency components for the aortic and pulmonary valve functions as well as the intra-ventricular and respiratory influences on the cardiovascular dynamics. The CWT is a very sensitive and reliable procedure for determining the three-dimensional (time-frequency-amplitude) of the oscillatory phenomena during each cardiac cycle, providing more, although complementary, information than the spectral analysis obtained with the FFT. Thanks to the FFT, exact values in Hz could be found for the different events produced in each cycle, and thus the information provided by CWT could be related to the information provided by FFT. The combination of both mathematical methodologies permitted identification of each component of the analyzed signals. The 3D representation allowed an easy comparison of the relative importance of the complex magnitudes in frequency for the different components of the pulsatile waves.

Time-frequency analysis of arterial pressure oscillations in anesthetized dogs : Effects of standardized hemorrhages

The purpose of this preliminary study was to investigate the advantages of the time-frequency analysis through the Continuous Wavelet Transform (CWT) compared to classical Fourier analysis using the Fast Fourier Transform (FFT) in arterial pressure signals from anesthetized mongrel dogs before and during standardized hemorrhages. Systemic arterial pressure pulsations were recorded using catheter-tip manometers. CWT and FFT were applied to arterial pressure pulsations to obtain module coefficients of this transformation and its associated contours during the evolution of progressive hemorrhages, in amounts of 15, 34, and 66% of the estimated total blood volume. This mathematical analysis enabled us to identify the evolution of the frequency components of aortic valve functions, heart dynamics, respiratory influences, and vasomotor activities. Furthermore, we isolated the modulating signal of amplitude modulation phenomenon present in the arterial pressure records, as described in previous papers, being the heart rate carrier frequency. The CWT is a very sensitive and reliable procedure to analyze (time-frequency) the oscillatory phenomena in two dimensions, and to provide more information than the FFT. This new analytical procedure may provide new insights in the study of shock pathophysiology.

Comparando fuerza tensil en incisiones cerradas con Nylon 5-0 y 2-octylcianoacrilato

Resumen es: Objetivo: Comparar la fuerza tensil de heridas cerradas mediante una sutura monofilamento no reabsorbible (nylon 5-0) y un polimero adhesivo (2-octylcian...