987 resultados para Stimulus


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The objective of this study was to evaluate and correlate quality of life (QoL), and stimulus perception of complete denture users, before and after the insertion of new prostheses. We selected 60 patients using bimaxillary complete conventional dentures who needed to replace their prostheses. During anamnesis, we collected demographic data and applied the Oral Health Impact Profile for Edentulous Patients (OHIP-EDENT) questionnaire and stimulus perception questionnaire (PERCEPTION). Before installation of new prostheses, the patients responded to OHIP-EDENT questionnaire, and on the day of installation, they responded to PERCEPTION questionnaire. At the patients 3-month follow-up, we re-administered the OHIP-EDENT and PERCEPTION questionnaires. The Wilcoxon and MacNemar tests were used to compare patient responses between the time points analysed. Most of the OHIP-EDENT items showed a highly significant impact of the new prostheses on oral health (P = 0.003). The PERCEPTION questionnaire data indicated that the patients experienced significant improvements (P < 0.05) in terms of their sensations with the new prostheses. Cross-lagged data analysis did not show any causality between the OHIP-EDENT and PERCEPTION questionnaires (ZPF test, P = 0.772). We concluded that the treatment was effective with respect to the patients QoL and their adaptation to the new prostheses.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study tested the adequacy of feeding as an unconditioned stimulus (US) to condition an endocrine response (plasma cortisol increase) in the cichlid fish Nile tilapia (Oreochromis niloticus). In a first study, conditioning was confirmed in grouped fish in the only experiment using single-held Nile tilapia. In this test a conditioned stimulus (CS - aeration off) was associated with a stressor (air emersion for 2 min - US). We then assessed whether several events of paired CS-US resulted in a conditioned endocrine response (CR), in this case an increase in plasma cortisol after presentation of the CS only. Before testing feeding as US, the postprandial or social holding condition for feeding effects on cortisol levels was tested. Nile tilapia showed increased cortisol after feeding associated to social context (grouped fish), but not to food only (single-held fish). In a third study, feeding was tested as US in an experiment similar to the first study but an increase in feeding-induced cortisol could not be conditioned. The absence of CR suggests that the stressor affects acquisition of this response, which may be a consequence of stimulus intensity or biological relevance. This study expands the recently reported Pavlovian conditioning paradigm for endocrine response in fish. (C) 2007 Elsevier B.V. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Includes bibliography

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Although glucocorticoids are widely used as antiinflammatory agents in clinical therapies, they may cause serious side effects that include insulin resistance and hyperinsulinemia. To study the potential functional adaptations of the islet of Langerhans to in vivo glucocorticoid treatment, adult Wistar rats received dexamethasone (DEX) for 5 consecutive days, whereas controls (CTL) received only saline. The analysis of insulin release in freshly isolated islets showed an enhanced secretion in response to glucose in DEX-treated rats. The study of Ca2 2+ signals by fluorescence microscopy also demonstrated a higher response to glucose in islets from DEX-treated animals. However, no differences in Ca2 2+signals were found between both groups with tolbutamide or KCl, indicating that the alterations were probably related to metabolism. Thus, mitochondrial function was explored by monitoring oxidation of nicotinamide dinucleotide phosphate autofluorescence and mitochondrial membrane potential. Both parameters revealed a higher response to glucose in islets from DEX-treated rats. The mRNA and protein content of glucose transporter-2, glucokinase, and pyruvate kinase was similar in both groups, indicating that changes in these proteins were probably not involved in the increased mitochondrial function. Additionally,weexplored the status of Ca2 2+-dependent signaling kinases. Unlike calmodulin kinase II, we found an augmented phosphorylation level of protein kinase Cα as well as an increased response of the phospholipase C/inositol 1,4,5-triphosphate pathway in DEX-treated rats. Finally, an increased number of docked secretory granules were observed in the β-cells of DEX animals using transmission electron microscopy. Thus, these results demonstrate that islets from glucocorticoid-treated rats develop several adaptations that lead to an enhanced stimulus-secretion coupling and secretory capacity. Copyright © 2010 by The Endocrine Society.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Includes bibliography

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Accumulating evidence demonstrates that chronic inflammation plays an important role in heart hypertrophy and cardiac diseases. However, the fine-tuning of cellular and molecular mechanisms that connect inflammatory process and cardiac diseases is still under investigation. Many reports have demonstrated that the overexpression of the cyclooxygenase-2 (COX-2), a key enzyme in the conversion of arachidonic acid to prostaglandins and other prostanoids, is correlated with inflammatory processes. Increased level of prostaglandin E2 was also found in animal model of left ventricle of hypertrophy. Based on previous observations that demonstrated a regulatory loop between COX-2 and the RNA-binding protein CUGBP2, we studied cellular and molecular mechanisms of a pro-inflammatory stimulus in a cardiac cell to verify if the above two molecules could be correlated with the inflammatory process in the heart. A cellular model of investigation was established and H9c2 was used.We also demonstrated a regulatory connection between COX-2 and CUGBP2 in the cardiac cells. Based on a set of different assays including gene silencing and fluorescence microscopy, we describe a novel function for the RNA-binding protein CUGBP2 in controlling the pro-inflammatory stimulus: subcellular trafficking of messenger molecules to specific cytoplasmic stress granules to maintain homeostasis. © 2013 International Federation for Cell Biology.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A "second generation" matching-to-sample procedure that minimizes past sources of artifacts involves (1) successive discrimination between sample stimuli, (2) stimulus displays ranging from four to 16 comparisons, (3) variable stimulus locations to avoid unwanted stimulus-location control, and (4) high accuracy levels (e.g., 90% correct on a 16-choice task in which chance accuracy is 6%). Examples of behavioral engineering with experienced capuchin monkeys included four-choice matching problems with video images of monkeys with substantially above-chance matching in a single session and 90% matching within six sessions. Exclusion performance was demonstrated by interspersing non-identical sample-comparison pairs within a baseline of a nine-comparison identity-matching-to-sample procedure with pictures as stimuli. The test for exclusion presented the newly "mapped" stimulus in a situation in which exclusion was not possible. Degradation of matching between physically non-identical forms occurred while baseline identity accuracy was sustained at high levels, thus confirming that Cebus cf. apella is capable of exclusion. Additionally, exclusion performance when baseline matching relations involved non-identical stimuli was shown.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Teaching the first instances of arbitrary matching-to-sample to nonhumans can prove difficult and time consuming. Stimulus control relations may develop that differ from those intended by the experimentereven when stimulus control shaping procedures are used. We present, in this study, efforts to identify sources of shaping program failure with a capuchin monkey. Procedures began with a baseline of identity matching. During subsequent shaping trials, compound comparison stimuli had two componentsone identical to and another different from the sample. The identical component was eliminated gradually by removing portions across trials (i.e., subtracting stimulus elements). The monkey performed accurately throughout shaping. At a late stage in the program, probe tests were conducted: (1) arbitrary matching trials that had all elements of the identical comparison removed and (2) other trials that included residual elements. During the test, the monkey performed at low levels on the former trials and higher levels on the latter. These results suggested that higher accuracy was due merely to continued control by the residual elements: the target arbitrary matching relations had not been learned. Thus, it appears that procedures that gradually transform identity matching baselines into arbitrary matching can fail by inadvertently shaping restricted control by residual elements. Subsequent probes at the end of the shaping series showed a successful transfer of stimulus control from identity to arbitrary matching after further programming steps apparently overcame the restricted stimulus control.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The relative lengths of the 2nd and 4th digits (2D:4D) is a negative biomarker for prenatal testosterone, and low 2D:4D may be associated with aggression. However, the evidence for a 2D:4D-aggression association is mixed. Here we test the hypothesis that 2D:4D is robustly linked to aggression in challenge situations in which testosterone is increased. Participants were exposed to an aggressive video and a control video. Aggression was measured after each video and salivary free testosterone levels before and after each video. Compared to the control video, the aggressive video was associated with raised aggression responses and a marginally significant increase in testosterone. Left 2D:4D was negatively correlated with aggression after the aggressive video and the strength of the correlation was higher in those participants who showed the greatest increases in testosterone. Left 2D:4D was also negatively correlated to the difference between aggression scores in the aggressive and control conditions. The control video did not influence testosterone concentrations and there were no associations between 2D:4D and aggression. We conclude that 2D:4D moderates the impact of an aggressive stimulus on aggression, such that an increase in testosterone resulting from a challenge is associated with a negative correlation between 2D:4D and aggression.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The aim of this study was to investigate the electroencephalographic (EEG) response of equidae to a castration stimulus. Study 1 included 11 mules (2 1/2-8 years; 230-315 kg) and 11 horses (1 1/2-3 1/2 years; 315-480 kg); study 2 included four ponies (15-17 months; 176-229 kg). They were castrated under halothane anesthesia after acepromazine premedication (IV [study 1] and intramuscular [study 2]) and thiopental anesthetic induction. Animals were castrated using a semiclosed technique (study 1) and a closed technique (study 2). Raw EEG data were analyzed and the EEG variables, median frequency (F50), total power (Ptot), and spectral edge frequency (F95), were derived using standard techniques at skin incision (skin) and emasculation (emasc) time points. Baseline values of F50, Ptot, and F95 for each animal were used to calculate percentage change from baseline at skin incision and emasculation. Differences were observed in Ptot and F50 data between hemispheres in horses but not mules (study 1) and in one pony (study 2). A response to castration (>10% change relative to baseline) was observed in eight horses (73% of animals) and four mules (36% of animals) for F50 and nine horses (82%) and four mules (36%) for Ptot. No changes in F95 data were observed in any animal in study 1. Responses to castration were observed in three ponies (75% of animals) for F50, one pony (25%) for F95, and all ponies for Ptot Alteration of acepromazine administration and castration technique produced a protocol that identified changes in EEG frequency and power in response to castration. (c) 2014 Elsevier Inc. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)