38 resultados para logic of influence (action)


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Transplantation of pancreatic islets constitutes a promising alternative treatment for type 1 diabetes. However, it is limited by the shortage of organ donors. Previous results from our laboratory have demonstrated beneficial effects of recombinant human prolactin (rhPRL) treatment on beta cell cultures. We therefore investigated the role of rhPRL action in human beta cell survival, focusing on the molecular mechanisms involved in this process. Human pancreatic islets were isolated using an automated method. Islet cultures were pre-treated in the absence or presence of rhPRL and then subjected to serum starvation or cytokine treatment. Beta cells were labelled with Newport green and apoptosis was evaluated using flow cytometry analysis. Levels of BCL2 gene family members were studied by quantitative RT-PCR and western blot. Caspase-8, -9 and -3 activity, as well as nitric oxide production, were evaluated by fluorimetric assays. The proportion of apoptotic beta cells was significantly lowered in the presence of rhPRL under both cell death-induced conditions. We also demonstrated that cytoprotection may involve an increase of BCL2/BAX ratio, as well as inhibition of caspase-8, -9 and -3. Our study provides relevant evidence for a protective effect of lactogens on human beta cell apoptosis. The results also suggest that the improvement of cell survival may involve, at least in part, inhibition of cell death pathways controlled by the BCL2 gene family members. These findings are highly relevant for improvement of the islet isolation procedure and for clinical islet transplantation.

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It has been suggested that the temporal control of rhythmic unimianual movements is different between tasks requiring continuous (e.g., circle drawing) and discontinuous movements (e.g., finger tapping). Specifically, for continuous movements temporal regularities are ail emergent property, whereas for tasks that involve discontinuities timing is ail explicit part of the action goal. The present experiment further investigated the control of continuous and discontinuous movements by comparing the coordination dynamics and attentional demands of bimanual continuous circle drawing with bimanual intermittent circle drawing. The intermittent task required participants to insert a 400 ms pause between each cycle while circling. Using dual-task methodology, 15 right-handed participants performed the two circle drawing tasks, while vocally responding to randomly presented auditory probes. The circle drawing tasks were performed in symmetrical and asymmetrical coordination modes and at movement frequencies of 1 Hz and 1.7 Hz. Intermittent circle drawing exhibited superior spatial and temporal accuracy and stability than continuous circle drawing supporting the hypothesis that the two tasks have different underlying control processes. In terms of attentional cost, probe RT was significantly slower during the intermittent circle drawing task than the continuous circle drawing task across both coordination modes and movement frequencies. Of interest was the finding that in the intermittent circling task reaction time (RT) to probes presented during the pause between cycles did not differ from the RT to probes occurring during the circling movement. The differences in attentional demands between the intermittent and continuous circle drawing tasks may reflect the operation of explicit event timing and implicit emergent timing processes, respectively. (C) 2008 Elsevier B.V. All rights reserved.

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Nitric oxide (NO) plays a key role in body temperature (Tb) regulation of mammals, acting on the brain to stimulate heat loss. Regarding birds, the putative participation of NO in the maintenance of Tb in thermoneutrality or during heat stress and the site of its action (periphery or brain) is unknown. Thus, we tested if NO participates in the maintenance of chicks` Tb in those conditions. We investigated the effect of intramuscular (im; 25, 50, 100 mg/kg) or intracerebroventricular (icv; 22.5, 45, 90, 180 mu g/animal) injections of the non selective NO synthase inhibitor L-NAME on Tb of 5-day-old chicks at thermoneutral zone (TNZ; 31-32 degrees C) and under heat stress (37 degrees C for 5-6 h). We also verified plasma and diencephalic nitrite/nitrate levels in non-injected chicks under both conditions. At TNZ, 100 mg/kg (im) or 45,90,180 mu g (icv) of L-NAME decreased Tb. A significant correlation between Tb and diencephalic, but not plasma, nitrite/nitrate levels was observed. Heat stress-induced hyperthermia was inhibited by all tested doses of L-NAME (im and icv). Tb was correlated neither with plasma nor with diencephalic nitrite/nitrate levels during heat stress. These results indicate the involvement of brain NO in the maintenance of Tb of chicks, an opposite action of that observed in mammals, and may modulate hyperthermia. (C) 2009 Elsevier Inc. All rights reserved.

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This paper proposes a simple high-level programming language, endowed with resources that help encoding self-modifying programs. With this purpose, a conventional imperative language syntax (not explicitly stated in this paper) is incremented with special commands and statements forming an adaptive layer specially designed with focus on the dynamical changes to be applied to the code at run-time. The resulting language allows programmers to easily specify dynamic changes to their own program`s code. Such a language succeeds to allow programmers to effortless describe the dynamic logic of their adaptive applications. In this paper, we describe the most important aspects of the design and implementation of such a language. A small example is finally presented for illustration purposes.

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In the present study, an acidic PLA(2), designated BI-PLA(2), was isolated from Bothrops leucurus snake venom through two chromatographic steps: ion-exchange on CM-Sepharose and hydrophobic chromatography on Phenyl-Sepharose. Bl-PLA(2) was homogeneous on SDS-PAGE and when submitted to 2D electrophoresis the molecular mass was 15,000 Da and pl was 5.4. Its N-terminal sequence revealed a high homology with other Asp49 acidic PLA(2)s from snake venoms. Its specific activity was 159.9 U/mg and the indirect hemolytic activity was also higher than that of the crude venom. Bl-PLA(2) induced low myotoxic and edema activities as compared to those of the crude venom. Moreover, the enzyme was able to induce increments in IL-12p40, TNF-alpha, IL-1 beta and IL-6 levels and no variation of IL-8 and IL-10 in human PBMC stimulated in vitro, suggesting that Bl-PLA2 induces proinflammatory cytokine production by human mononuclear cells. Bothrops leucurus venom is still not extensively explored and knowledge of its components will contribute for a better understanding of its action mechanism. (C) 2011 Elsevier Inc. All rights reserved.

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This study aims to evaluate the feasibility of using simple techniques - pollen abortion rates, passive diffusive tubes (NO(2)) and trace element accumulation in tree barks - when determining the area of influence of pollution emissions produced in a traffic corridor. Measurements were performed at 0, 60 and 120 meters from a major road with high vehicular traffic, taking advantage of a sharp gradient that exists between the road and a cemetery. NO(2) values and trace elements measured at 0 meters were significantly higher than those measured at more distant points. Al, S. Cl, V. Fe, Cu, and Zn exhibited a higher concentration in tree barks at the vicinity of the traffic corridor. The same pattern was observed for the pollen abortion rates measured at the three different sites. Our data suggests that simple techniques may be applied either to validate dispersion land-based models in an urban settings or, alternatively, to provide better spatial resolution to air pollution exposure when high-resolution pollution monitoring data are not available. (C) 2011 Elsevier B.V. All rights reserved.

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Through the study of the action of the inquisition commissioners, this article seeks to reveal the relations between the Portuguese Inquisition and the ecclesiastical structure of the Minas Gerais State Captaincy in the colonial period. The focus of the analysis will be the making and the action of the network of Holy Inquisition commissioners in the gold Captaincy. What was the profile of these commissioners? How were they recruited from the local ecclesiastical hierarchy? What was the role assigned to them in the inquisitional action that took place in Minas Gerais? How did they act? What was the relationship between the introduction of the commissioners into the local ecclesiastical structures and the commissioners` inquisitorial activities?

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Sepsis remains a major cause of morbidity and mortality mainly because of sepsis-induced multiple organ dysfunction. In contrast to preclinical studies, most clinical trials of promising new treatment strategies for sepsis have failed to demonstrate efficacy. Although many reasons could account for this discrepancy, the misinterpretation of preclinical data obtained from experimental studies and especially the use of animal models that do not adequately mimic human sepsis may have been contributing factors. In this review, the potentials and limitations of various animal models of sepsis are discussed to clarify to which extent these findings are relevant to human sepsis. Such models include intravascular infusion of endotoxin or live bacteria, bacterial peritonitis, cecal ligation and perforation, soft tissue infection, pneumonia or meningitis models using different animal species including rats, mice, rabbits, dogs, pigs, sheep, and nonhuman primates. Despite several limitations, animal models remain essential in the development of all new therapies for sepsis and septic shock because they provide fundamental information about the pharmacokinetics, toxicity, and mechanism of drug action that cannot be replaced by other methods. New therapeutic agents should be studied in infection models, even after the initiation of the septic process. Furthermore, debility conditions need to be reproduced to avoid the exclusive use of healthy animals, which often do not represent the human septic patient.

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In this paper we present a new neuroeconomics model for decision-making applied to the Attention-Deficit/Hyperactivity Disorder (ADHD). The model is based on the hypothesis that decision-making is dependent on the evaluation of expected rewards and risks assessed simultaneously in two decision spaces: the personal (PDS) and the interpersonal emotional spaces (IDS). Motivation to act is triggered by necessities identified in PDS or IDS. The adequacy of an action in fulfilling a given necessity is assumed to be dependent on the expected reward and risk evaluated in the decision spaces. Conflict generated by expected reward and risk influences the easiness (cognitive effort) and the future perspective of the decision-making. Finally, the willingness (not) to act is proposed to be a function of the expected reward (or risk), adequacy, easiness and future perspective. The two most frequent clinical forms are ADHD hyperactive (AD/HDhyp) and ADHD inattentive (AD/HDdin). AD/HDhyp behavior is hypothesized to be a consequence of experiencing high rewarding expectancies for short periods of time, low risk evaluation, and short future perspective for decision-making. AD/HDin is hypothesized to be a consequence of experiencing high rewarding expectancies for long periods of time, low risk evaluation, and long future perspective for decision-making.

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Background: Homeopathy is based on the principle of similitude (similia similibus curentur) using medicines that cause effects similar to the symptoms of disease in order to stimulate the reaction of the organism. Such vital, homeostatic or paradoxical reaction of the organism is closely related to rebound effect of drugs. Method: Review of the literature concerning the rebound effects of drugs used to suppress gastric acidity, particularly proton pump inhibitors (PPIs). Results: The mechanism of action of these effects is discussed. Rebound in terms of clinical symptoms and physiological effects occur in about 40% of people taking PPIs, their timing depends on the half-life of the drug and the adaptation period of the physiological mechanisms involved. The wide use of PPIs may be linked to the rising incidence of carcinoid tumours. Conclusions: These findings support Hahnemann`s concept of secondary action of drugs. We are developing a homeopathic materia medica and repertory of modern drugs on the basis of reported rebound effects. Homeopathy (2011) 100, 148-156.

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The study aimed to elucidate electrophysiological and cortical mechanisms involved in anticipatory actions when healthy subjects had to catch balls in free drop; specifically through quantitative electroencephalography (qEEG) alpha absolute power changes. Our hypothesis is that during the preparation of motor action (i.e., 2 s before ball`s drop) occurred integration among left medial frontal, left primary somatomotor and left posterior parietal cortices, showing a differentiated activity involving expectation, planning and preparedness. This hypothesis supports a lateralization of motor function. Although we contend that in right-handers the left hemisphere takes on a dominant role for the regulation of motor behavior. The sample was composed of 23 healthy subjects (13 male and 10 female), right handed, with ages varying between 25 and 40 years old (32.5 +/- 7.5), absence of mental and physical illness, right handed, and do not make use of any psychoactive or psychotropic substance at the time of the study. The experiment consisted of a task of catching balls in free drop. The three-way ANOVA analysis demonstrated an interaction between moment and position in left medial frontal cortex (F3 electrode), somatomotor cortex (C3 electrode) and posterior parietal cortex (P3 electrode: p < 0.001). Summarizing, through experimental task employed, it was possible to observe integration among frontal, central and parietal regions. This integration appears to be more predominant in expectation, planning and motor preparation. In this way, it established an absolute predominance of this mechanism under the left hemisphere. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

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The essential oil of Eucalyptus tereticornis (EOET) has pharmacological activities but their effects on the gastrointestinal tract are yet unknown. It possesses alpha- and beta-pinene as minor constituents, isomers largely used as food or drink additives. In this work, we studied their actions on gut motility. After feeding with a liquid test meal, conscious rats received perorally EOET, alpha-, or beta-pinene, and the fractional dye retention was determined. EOET and its constituents decreased the gastric retention. In anesthetized rats, pinenes increased gastric tonus, while enhancing the meal progression in the small intestine of conscious rats. Both alpha- and beta-pinene contracted gastric strips in vitro but relaxed the duodenum. Conversely, EOET relaxed both the gastric and duodenal strips. In conclusion, EOET accelerates the gastric emptying of liquid, and part of its action is attributed to the contrasting effects induced by alpha- and beta-pinene on the gut.

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Objective: This study compared the clinical efficacy of 4% articaine (A200) and 0.5% bupivacaine (B200), both with 1: 200,000 epinephrine, for lower third molar removal. Study design: Fifty patients underwent removal of symmetrically positioned lower third molars, in 2 separate appointments, under local anesthesia either with A200 or B200, in a double-blind, randomized, and crossover manner. Time to onset, duration of postoperative analgesia, duration of anesthetic action on soft tissues, intraoperative bleeding, and hemodynamic parameters were evaluated. Results: A statistically significant difference between the time to onset of A200 (1.66 +/- 0.13 minutes) and B200 (2.51 +/- 0.21 minutes) was found (P < .05). There was no statistically significant difference in the duration of analgesia, whether the patient was subjected to osteotomy or not, regardless of the local anesthetic used (3 to 4 hours; P < .05). However, when patients received B200 they experienced a statistically significant longer period of anesthesia on the soft tissues as compared with when they had received A200 (around 5 hours and 4 hours, respectively, P < .05). The surgeon`s rating of intraoperative bleeding was considered very close to minimal for both anesthetics. In the surgeries with osteotomy, the comparison between A200 and B200 showed statistically significant differences in the diastolic (64 mm Hg and 68 mm Hg, respectively, P = .001) and mean arterial pressure (86 mm Hg and 89 mm Hg, respectively, P = .031) when data from all the surgical phases were pooled. Additionally, the mouth opening at the suture removal was statistically different for A200 and B200 solutions (91.90% +/- 3.00% and 88.57% +/- 2.38% of the preoperative measure, respectively) when surgeries required bone removal (P < .05). Conclusions: In comparison with 0.5% bupivacaine, 4% articaine (both with 1: 200,000 epinephrine) provided a shorter time to onset and comparable hemostasis and postoperative pain control with a shorter duration of soft tissue anesthesia in lower third molar removal.

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This paper presents an analysis of ground-based Aerosol Optical Depth (AOD) observations by the Aerosol Robotic Network (AERONET) in South America from 2001 to 2007 in comparison with the satellite AOD product of Moderate Resolution Imaging Spectroradiometer (MODIS), aboard TERRA and AQUA satellites. Data of 12 observation sites were used with primary interest in AERONET sites located in or downwind of areas with high biomass burning activity and with measurements available for the full time range. Fires cause the predominant carbonaceous aerosol emission signal during the dry season in South America and are therefore a special focus of this study. Interannual and seasonal behavior of the observed AOD at different sites were investigated, showing clear differences between purely fire and urban influenced sites. An intercomparison of AERONET and MODIS AOD annual correlations revealed that neither an interannual long-term trend may be observed nor that correlations differ significantly owing to different overpass times of TERRA and AQUA. Individual anisotropic representativity areas for each AERONET site were derived by correlating daily AOD of each site for all years with available individual MODIS AOD pixels gridded to 1 degrees x 1 degrees. Results showed that for many sites a good AOD correlation (R(2) > 0.5) persists for large, often strongly anisotropic, areas. The climatological areas of common regional aerosol regimes often extend over several hundreds of kilometers, sometimes far across national boundaries. As a practical application, these strongly inhomogeneous and anisotropic areas of influence are being implemented in the tropospheric aerosol data assimilation system of the Coupled Chemistry-Aerosol-Tracer Transport Model coupled to the Brazilian Regional Atmospheric Modeling System (CCATT-BRAMS) at the Brazilian National Institute for Space Research (INPE). This new information promises an improved exploitation of local site sampling and, thus, chemical weather forecast.

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The aim of this study was to evaluate the role of cyclooxygenase (COX) in venous vascular reactivity changes after an oral lipid overload (OLO). Venous endothelial function (dorsal hand vein technique) was evaluated in fasting, 30 minutes after COX inhibition (aspirin-fasting), 2 to 4 hours after an OLO (1000 kcal, 58% fat), and again after COX inhibition (aspirin-OLO, 600 mg/200 mL water) in 10 healthy adults (age, 28.1 +/- 1.3 years; body mass index, 22.3 +/- 0.6 kg/m(2)). Fasting, 2- to 4-hour post-OLO, and 60-minute postaspirin plasma glucose, insulin, and lipids were also evaluated. The OLO increased triglycerides and insulin, reduced low-density lipoprotein and high-density lipoprotein, but glycemia and total cholesterol remained unchanged. There were no metabolic differences between OLO and aspirin-OLO. In fasting, aspirin reduced acetylcholine-induced venodilation (107.0% +/- 14% versus 57.3% +/- 11%; P < 0.001). Vascular reactivity was blunted after the OLO (phenylephrine dose: 0.3 +/- 0.2 fasting versus 1.9 +/- 0.8 nmol/min after OLO; P < 0.001) and was partially corrected by aspirin (0.4 +/- 0.2; P < 0.001). Similar changes were observed in maximum venodilation after acetylcholine (107.0% +/- 14% fasting versus 60.4% +/- 9% after OLO, P < 0.001; aspirin-OLO: 95.9% +/- 6%; P < 0.001). The responses to sodium nitroprusside remained unchanged during the study. We conclude that the OLO reduction in the endothelium-dependent venoconstruction and venodilation is partially the result of the action of COX.