A. M. de Oliveira

The balloon catheter induces an increase in contralateral carotid artery reactivity to angiotensin II and phenylephrine

The effects of balloon injury on the reactivity of ipsilateral and contralateral carotid arteries were compared to those observed in arteries from intact animals (control arteries). Carotid arteries were obtained from Wistar rats 2, 4, 7, 15, 30 or 45 days after injury and mounted in an isolated organ bath. Reactivity to angiotensin II (Ang II), phenylephrine (Phe) and bradykinin (BK) was studied. Curves were constructed in the absence or presence of endothelium or after incubation with 10 μM indomethacin, 500 μM valeryl salicylate or 0.1 μM celecoxib. Phe, Ang II and BK maximum effects (Emax) were decreased in ipsilateral arteries when compared to control arteries. No differences were observed among pD2 or Hill coefficient. Emax to Phe (4 and 7 days) and to Ang II (15 and 30 days) increased in the contralateral artery. In addition, Phe or Ang II reactivity was not significantly different in aorta rings from control or carotid‐injured animals. The increased responsiveness of contralateral artery was not due to changes in carotid blood flow or resting membrane potential. The endothelium‐dependent inhibitory component is not present in the contraction of contralateral arteries and it is not related to superoxide anion production. Indomethacin decreased contralateral artery responsiveness to Phe and Ang II. Valeryl salicylate reduced the Ang II response in contralateral and control arteries. Celecoxib decreased the Phe Emax of contralateral artery. In conclusion, decreased endothelium‐derived factors and increased prostanoids appear to be responsible for the increased reactivity of contralateral arteries after injury.

Gender‐specific vascular effects elicited by chronic ethanol consumption in rats: a role for inducible nitric oxide synthase

Epidemiological data suggest that the risk of ethanol‐associated cardiovascular disease is greater in men than in women. This study investigates the mechanisms underlying gender‐specific vascular effects elicited by chronic ethanol consumption in rats.

Increased endothelin-1 reactivity and endothelial dysfunction in carotid arteries from rats with hyperhomocysteinemia

Background and purpose:  There are interactions between endothelin‐1 (ET‐1) and endothelial vascular injury in hyperhomocysteinemia (HHcy), but the underlying mechanisms are poorly understood. Here we evaluated the effects of HHcy on the endothelin system in rat carotid arteries.

Chronic ethanol intake modulates vascular levels of endothelin-1 receptor and enhances the pressor response to endothelin-1 in anaesthetized rats

The contribution of endothelin‐1 (ET‐1) to vascular hyper‐reactivity associated with chronic ethanol intake, a major risk factor in several cardiovascular diseases, remains to be investigated.

Balloon catheter injury abolishes phenylephrine-induced relaxation in the rat contralateral carotid

The consequences of compensatory responses to balloon catheter injury in rat carotid artery, on phenylephrine‐induced relaxation and contraction in the contralateral carotid artery were studied.

Vascular non‐endothelial nitric oxide induced by swimming exercise stress in rats

1. Herein, we report the effects of acute or chronic forced swimming on vascular responsiveness to angiotensin (Ang) II.

Mixed H2/H∞ control of hidden Markov jump systems

Summary In this work, we study the mixed H2/H∞ control for Markov jump linear systems with hidden Markov parameters. The hidden Markov process is denoted by (θ(k),θ^(k)), where the nonobservable component θ(k) represents the mode of operation of the system, whereas θ^(k) represents the observable component provided by a detector. The goal is to obtain design techniques for mixed H2/H∞ control problems, with the controllers depending only on the estimate θ^(k), for problems formulated in 3 different forms: (i) minimizing an upper bound on the H2 norm subject to a given restriction on the H∞ norm; (ii) minimizing an upper bound on the H∞ norm, while limiting the H2 norm; and (iii) minimizing a weighted combination of upper bounds of both the H2 and H∞ norms. We propose also new conditions for synthesizing robust controllers under parametric uncertainty in the detector probabilities and in the transition probabilities. The so-called cluster case for the mixed H2/H∞ control problem is also analyzed under the detector approach. The results are illustrated by means of 2 numerical examples.

ℋ ∞ -filtering design for discrete-time Markov Jump Systems with hidden parameters

In this paper we tackle the ℋ_∞ filtering problem for a discrete-time Markov Jump Linear System (MJLS) with hidden parameters. We consider a hidden Markov model (θ(k); θ̂(k)) in which θ(k) is not accessible and corresponds to the mode of operation of the system, while θ̂(k) is a signal coming from a detector. The signal θ̂(k) acts as an estimation of θk) and is the observable part of the hidden Markov model available to the filter. This approach generalizes several cases found in literature like the complete observation case, the mode independent case and the Markov models in fault-tolerant control. In this context, a new filter structure depending only on θ̂(k) is proposed and the problem of obtaining an upper bound of the ℋ_∞ norm of the estimation error is studied. Sufficient conditions in terms of linear matrix inequalities (LMI) are given. The results are illustrated by a numerical example.

Mixed 2/∞ filtering for Markov jump linear systems

ABSTRACT We study in this work the mixed -filtering problem for Markov jump linear systems in a partial observation context. Rather than the Markov chain , we consider that only an estimation coming from a detector is available to the filter. We present a sufficient condition for the synthesis of a filter depending only on such that the estimation errors for the and filtering problems are bounded by given scalars. The robust mixed filtering considering that the transition and detection probabilities are uncertain, as well as the complete observation, cluster and mode-independent cases, are also studied. The results are given in terms of linear matrix inequalities and are illustrated by a numerical example.

MORPHOLOGIC STUDY OF THE MASSETER MUSCLE OF GERBIL (Meriones unguiculatus)

El dano de los musculos masticadores relacionados con desordenes craneomandibulares son aspectos comunes en la clinica. Es importante contar con datos morfologicos de estos musculos en el sistema estomatognatico. El proposito de este trabajo es mostrar la morfologia del musculo masetero del gerbil Meriones unguiculatus, desde el nivel macroscopico hasta el de microscopia electronica. En la observacion macroscopica fueron utilizados 5 animales que fueron perfundidos con solucion de formalina al 10%. Las disecciones fueron fotografiadas. Posteriormente, los musculos fueron removidos e sumergidos en la solucion de formalina, por unos pocos dias. Las muestras fueron procesadas a traves de tecnicas histologicas convencionales y sumergidas en parafina. Cortes seriados de 6 µm fueron tenidos con H. E. analizados y fotografiados con un fotomicroscopio JENAMED. Nuestros resultados mostraron que el musculo masetero presentaba 5 fasciculos, los cuales se mezclaban en la porcion media, y algunos husos estaban fusionados con la capsula externa de ellos mismos, pareciendo husos gigantes