Evaluation of inflammatory response induced by different types of daily contact lenses

Dissertação de mestrado em Genética Molecular

Relative information entropy in cosmology: The problem of information entanglement

The necessary information to distinguish a local inhomogeneous mass density field from its spatial average on a compact domain of the universe can be measured by relative information entropy. The Kullback-Leibler (KL) formula arises very naturally in this context, however, it provides a very complicated way to compute the mutual information between spatially separated but causally connected regions of the universe in a realistic, inhomogeneous model. To circumvent this issue, by considering a parametric extension of the KL measure, we develop a simple model to describe the mutual information which is entangled via the gravitational field equations. We show that the Tsallis relative entropy can be a good approximation in the case of small inhomogeneities, and for measuring the independent relative information inside the domain, we propose the R\'enyi relative entropy formula.

Toxicity induced by a metal mixture (Cd, Pb and Zn) in the yeast Pichia kudriavzevii: The role of oxidative stress

The present work aims to contribute for the elucidation of the role of oxidative stress in the toxicity associated with the exposure of Pichia kudriavzevii to multi-metals (Cd, Pb and Zn). Cells of the non-conventional yeast P. kudriavzevii exposed for 6 h to the action of multi-metals accumulated intracellular reactive oxygen species (ROS), evaluated through the oxidation of the probe 2,7-dichlorodihydrofluorescein diacetate. A progressive loss of membrane integrity (monitored using propidium iodide) was observed in multi-metal-treated cells. The triggering of intracellular ROS accumulation preceded the loss of membrane integrity. These results suggest that the disruption of membrane integrity can be attributed to the oxidative stress. The exposure of yeast cells to single metal showed that, under the concentrations tested, Pb was the metal responsible for the induction of the oxidative stress. Yeast cells coexposed to an antioxidant (ascorbic acid) and multi-metals did not accumulate intracellular ROS, but loss proliferation capacity. Together, the data obtained indicated that intracellular ROS accumulation contributed to metal toxicity, namely for the disruption of membrane integrity of the yeast P. kudriavzevii. It was proposed that Pb toxicity (the metal responsible for the toxic symptoms under the conditions tested) result from the combination of an ionic mechanism and the intracellular ROS accumulation.

Vascular disease modeling using induced pluripotent stem cells: Focus in Hutchinson-Gilford Progeria Syndrome

Transparency document related to this article can be found online at http://dx.doi.org/10.1016/j.bbrc.2015.10.014

Influence of angiotensin II receptor subtypes of the paraventricular nucleus on the physiological responses induced by angiotensin II injection into the medial septal area

OBJECTIVE: We determined the effects of losartan and PD 123319 (antagonists of the AT1 and AT2 angiotensin receptors, respectively), and [Sar¹, Ala8] ANG II (a relatively peptide antagonist of angiotensin receptors) injected into the paraventricular nucleus (PVN) on water and 3% NaCl intake, and the diuretic, natriuretic, and pressor effects induced by administration of angiotensin II (ANG II) into the medial septal area (MSA) of conscious rats. METHODS: Holtzman rats were used . Animals were anesthetized with tribromoethanol (20 mg) per 100 grams of body weight, ip. A stainless steel guide cannula was implanted into the MSA and PVN. All drugs were injected in 0.5-mul volumes for 10-15 seconds. Seven days after brain surgery, water and 3% NaCl intake, urine and sodium excretion, and arterial blood pressure were measured. RESULTS: Losartan (40 nmol) and [Sar¹, Ala8] ANG II (40 nmol) completely eliminated whereas PD 123319 (40 nmol) partially blocked the increase in water and sodium intake and the increase in arterial blood pressure induced by ANG II (10 nmol) injected into the MSA. The PVN administration of PD 123319 and [Sar¹, Ala8] ANG II blocked whereas losartan attenuated the diuresis and natriuresis induced by MSA administration of ANG II. CONCLUSION: MSA involvement with PVN on water and sodium homeostasis and arterial pressure modulation utilizing ANGII receptors is suggested.

Mecanismos neurobiologicos involucrados en la sensibilizacion emocional inducida por abstinencia a drogas de abuso y estrés. Neurobiological mechanisms involved in emotional sensitization induced by withdrawal from drugs of abuse and stress.

El objetivo principal de este proyecto es estudiar los mecanismos neurobiológicos involucrados en el proceso de sensibilización emocional inducido por la abstinencia a drogas de abuso o por la exposición a un estímulo estresante de caracteristicas incontrolables. El modelo animal de sensibilización a utilizar en este proyecto es la facilitación en la formación de memoria de miedo producida por dichos tratamientos. Nuestra hipótesis sugiere que este proceso es el resultado de un mecanismo desinhibitorio de las interneuronas GABAérgicas del complejo basolateral de la amigdala. Por lo tanto se proponen los siguientes experimentos: 1) El estudio del curso temporal del efecto facilitador sobre la formación de una nueva memoria de miedo luego de la abstinencia a drogas o la exposición a un estímulo estresante (inmovilización). 2) La evaluación de la liberación"in vivo" de dopamina del complejo basolateral de la amigdala durante la adquisición y la expresión de la memoria de miedo en animales previamente expuestos a la abstinencia o al estres. 3) El estudio de la infusión local de antagonistas de receptores dopaminérgicos en el complejo basolateral de la amígdala (BLA) o en el nucleo central de la amígdala (CeA) antes del estrés sobre la adquisición y la expresión de una memoria de miedo. 4) La determinación de la actividad de ERK 1/2 y CREB en el complejo basolateral de la amigdala o en el nucleo central de la amígdala durante la adquisición y la expresión de una memoria de miedo en animales abstinentes o estresados. 5)El estudio de la infusión local de inhibidores de la MEK 1/2 en el complejo basolateral de la amigdala o en el nucleo central de la amígdala antes del estrés sobre la adquisición y la expresión de una memoria de miedo. La facilitación para generar memorias de miedo podría ser un componente crítico del síndrome de abstinencia al etanol responsable de las altas tasas de recurrencia asociadas con el alcoholismo. Por lo tanto se investigará el efecto de la evocación de la memoria de miedo sobre la autoadministración de etanol utilizando un paradigma de libre elección entre agua y soluciones de concentración creciente de etanol en animales en abstinencia al etanol. Con el objeto de investigar si las propiedades reforzantes del etanol están involucradas en el potencial aumento de la ingesta de etanol inducido por la evocación de una memoria de miedo, se evaluará el efecto reforzante de etanol utilizando el paradigma de preferencia por un contexto asociado al etanol.

contribution of horizontal. intracortical connections to learning-induced gamma oscillations

Magdeburg, Univ., Fak. für Naturwiss., Diss., 2011

Instability of excitation waves induced by electrical fields

Pyrogallol, uncatalyzed bromate oscillator, electric field, pulse wave, Belousov-Zhabotinsky reaction, reversal