953 resultados para Control-Lyapunov Functions


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Central chemoreception, the detection of CO(2)/H(+) within the brain and the resultant effect on ventilation, was initially localized at two areas on the ventrolateral medulla, one rostral (rVLM-Mitchell`s) the other caudal (cVLM-Loeschcke`s), by surface application of acidic solutions in anesthetized animals. Focal dialysis of a high CO(2)/H(+) artificial cerebrospinal fluid (aCSF) that produced a milder local pH change in unanesthetized rats (like that with a similar to 6.6 mm Hg increase in arterial P(CO2)) delineated putative chemoreceptor regions for the rVLM at the retrotrapezoid nucleus and the rostral medullary raphe that function predominantly in wakefulness and sleep, respectively. Here we ask if chemoreception in the cVLM can be detected by mild focal stimulation and if it functions in a state dependent manner. At responsive sites just beneath Loeschcke`s area, ventilation was increased by, on average, 17% (P < 0.01) only in wakefulness. These data support our hypothesis that central chemoreception is a distributed property with some sites functioning in a state dependent manner. (C) 2010 Elsevier B.V. All rights reserved.

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The D-mannose binding lectin ArtinM from Artocarpus integrifolia, previously known as KM+ and artocarpin. is considered a stimulant of Th1-type immunity, which is able to confer resistance to some intracellular pathogens. In addition, ArtinM induces neutrophil migration by haptotaxis through simultaneous interactions of its carbohydrate recognition domains (CRDs) with glycans expressed on the extracellular matrix and the neutrophil surface. In the present study, we have expanded the characterization of ArtinM as a neutrophil activator. Exposure of neutrophils to ArtinM for 15 min resulted in tyrosine phosphorylation of intracellular proteins, a process that was selectively inhibited by D-mannose or mannotriose. Shortly after stimulation, neutrophils secreted high levels of LTB(4) and underwent shedding of L-selectin from their surface. Exposure to ArtinM enhanced neutrophil functions, such as respiratory burst and zymozan and Listeria monocytogenes phagocytosis. In addition, ArtinM-stimulated neutrophils displayed increased CXCL-8 secretion and TLR2 gene transcription. These results demonstrate that ArtinM is able to induce potent neutrophil activation, a feature that should be strongly considered in the assessment of the lectin capacity to confer resistance against infections. (C) 2009 Elsevier B.V. All rights reserved.

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Objective: To investigate the effect of aerobic physical training on cardiovascular autonomic control in ovariectomized rats using different approaches. Design: Female Wistar rats were divided into four groups: sedentary sham rats (group SSR), trained sham rats (group TSR), sedentary ovariectomized rats (group SOR), and trained ovariectomized rats (group TOR). Animals from the trained groups were submitted to a physical training protocol (swimming) for 12 weeks. Results: Pharmacological evaluation showed that animals from group TSR had an increase in their cardiac vagal tonus compared with the animals from groups SSR and SOR. The analysis of heart rate variability (HRV) showed that groups TSR and SOR had fewer low-frequency oscillations (0.20-0.75 Hz) compared with groups SSR and TOR. When groups TSR and SOR were compared, the former was found to have fewer oscillations. With regard to high-frequency oscillations (0.75-2.5 Hz), group SSR had a reduction compared with the other groups, whereas group TSR had the greatest oscillation compared with groups SOR and TOR, with all values expressed in normalized units. Analysis of HRV was performed after pharmacological blockade, and low-frequency oscillations were found to be predominantly sympathetic in sedentary animals, whereas there was no predominance in trained animals. Conclusion: Ovariectomy did not change the tonic autonomic control of the heart and, in addition, reduced the participation of sympathetic component in cardiac modulation. Physical training, on the other hand, increased the participation of parasympathetic modulation on the HRV, including ovariectomized rats.

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We have investigated the ovariectomy effects on the cardiovascular autonomic adaptations induced by aerobic physical training and the role played by nitric oxide (NO). Female Wistar rats (n =70) were divided into five groups: Sedentary Sham (SS): Trained Sham (TS); Trained Hypertensive Sham treated with N(C)-nitro-L-arginine methyl ester (L-NAME) (THS): Trained Ovariectomized (TO); and Trained Hypertensive Ovariectomized treated with L-NAME (THO). Trained groups were submitted to a physical training during 10 weeks. The cardiovascular autonomic control was investigated in all groups using different approaches: 1) pharmacological evaluation of autonomic tonus with methylatropine and propranolol; 2) analysis of heart rate (HR) and systolic arterial pressure (AP) variability; 3) spontaneous baroreflex sensitivity (BRS) evaluation. Hypertension was observed in THS and THO groups. Pharmacological analysis showed that TS group had increased predominance of autonomic vagal tonus compared to SS group. HR and intrinsic HR were found to be reduced in all trained animals. TS group, compared to other groups, showed a reduction in LF oscillations (LF=0.2-0.75 Hz) of pulse interval in both absolute and normalized units as well as an increase in HF oscillations (HF=0.75-2.50 Hz) in normalized unit. FIRS analysis showed that alpha-index was different between all groups. TS group presented the greatest value, followed by the TO, SS. THO and THS groups. Ovariectomy has negative effects on cardiac autonomic modulation in trained rats, which is characterized by an increase in the sympathetic autonomic modulation. These negative effects suggest NO deficiency. In contrast, the ovariectomy seems to have no effect on AP variability. (C) 2008 Elsevier B.V. All rights reserved.

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Following the discovery of the melatonin by Lerner et al. (1958), new research and perspectives were developed in order to improve the knowledge regarding the pineal gland. This hormone is not only related to the circadian control but also influences other behavioral functions such as the reproductive cycle and thermoregulation. In this study the morphology of the pineal gland (epiphysis cerebri) from 20 dogs were analyzed by means of macroscopic and microscopic evaluation. The shape of the gland ranged from conic to ""tongue-like shape"" (in relation to human tongue). The gland color ranged from beige to gray-brownish and it had a gelatinous consistency. The width and length of the glands ranged from 1.38 to 2.39 mm and 1.53 to 2.96 mm, respectively. Capsule, septa, pinealocytes, glial cells and pigment granules were microscopically found in all glands. No calcareous concretions were observed.

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Neonatal calf diarrhea is a multi-etiology syndrome of cattle and direct detection of the two major agents of the syndrome, group A rotavirus and Bovine coronavirus (BCoV) is hampered by their fastidious growth in cell culture. This study aimed at developing a multiplex semi-nested RT-PCR for simultaneous detection of BCoV (N gene) and group A rotavirus (VP1 gene) with the addition of an internal control (mRNA ND5). The assay was tested in 75 bovine feces samples tested previously for rotavirus using PAGE and for BCoV using nested RT-PCR targeted to RdRp gene. Agreement with reference tests was optimal for BCoV (kappa = 0.833) and substantial for rotavirus detection (kappa = 0.648). the internal control, ND5 mRNA, was detected successfully in all reactions. Results demonstrated that this multiplex semi-nested RT-PCR was effective in the detection of BCoV and rotavirus, with high sensitivity and specificity for simultaneous detection of both viruses at a lower cost, providing an important tool for studies on the etiology of diarrhea in cattle. (C) 2010 Elsevier B.V. All rights reserved.

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The population dynamics of stray dogs is simulated to assess the effects of sterilization and euthanasia. From simulations representing less than 5 years, sterilization is less efficient than euthanasia to reduce the stray dog population, considering similar rates, but the total number of sterilized dogs is less than the total number of euthanized dogs per km(2) per year. Over 20 years, both strategies have similar efficiency. Beyond a certain rate of dog abandonment, both strategies are inefficient.

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The Rhipicephalus (Boophilus) microplus BM86 and BM95 glycoproteins are homologous proteins that protect cattle against tick infestations. In this study, we demonstrated that the recombinant chimeric protein comprising tick BM95 immunogenic peptides fused to the A. marginale MSP1a N-terminal region for presentation on the Escherichia coli membrane was protective against R. microplus infestations in rabbits. This system provides a novel and simple approach for the production of tick protective antigens by surface display of antigenic protein chimera on live E. coli and suggests the possibility of using recombinant bacterial membrane fractions for vaccination against cattle tick infestations. (C) 2009 Elsevier Ltd. All rights reserved.

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P>Aim The aim of this study was to investigate the possible associations between isolated growth hormone deficiency (IGHD) and periodontal attachment loss (PAL) in adults affected by congenital IGHD. Materials and methods Forty-five previously identified IGHD subjects were eligible for this study. The final study sample comprised 32 cases (gender:20M/12F; age:44.8 +/- 17.5) matched for age, gender, diabetes, smoking status and income to 32 controls (non-IGHD subjects). Participants were submitted to a full-mouth clinical examination of six sites per tooth and were interviewed using a structured, written questionnaire. Periodontitis was defined as proximal PAL >= 5 mm affecting >= 30% of teeth. Results No significant differences were observed in the percentage of sites with visible plaque between IGHD and non-IGHD subjects (59.4% versus 46.9%, p=0.32). IGHD subjects had significant less supragingival calculus (31.3% versus 59.4%, p=0.02) and more bleeding on probing (71.9% versus 18.8%, p < 0.01) than controls. PAL >= 5 mm was significantly more prevalent (100% versus 71.9%, p < 0.01) and affected more teeth (30.5% versus 6.7%, p < 0.01) in cases than in controls. After adjusting for supragingival calculus, IGHD cases had a higher likelihood of having periodontitis than controls (OR=17.4-17.8, 95% CI=2.3-134.9, p=0.004-0.005). Conclusion Congenital IGHD subjects have a greater chance of having PAL.