957 resultados para cardiac autonomic control
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Background: The Lateral Septal Area (LSA) is involved with autonomic and behavior responses associated to stress. In rats, acute restraint (RS) is an unavoidable stress situation that causes autonomic (body temperature, mean arterial pressure (MAP) and heart rate (HR) increases) and behavioral (increased anxiety-like behavior) changes in rats. The LSA is one of several brain regions that have been involved in stress responses. The aim of the present study was to investigate if the neurotransmission blockade in the LSA would interfere in the autonomic and behavioral changes induced by RS. Methodology/Principal Findings: Male Wistar rats with bilateral cannulae aimed at the LSA, an intra-abdominal datalogger (for recording internal body temperature), and an implanted catheter into the femoral artery (for recording and cardiovascular parameters) were used. They received bilateral microinjections of the non-selective synapse blocker cobalt chloride (CoCl(2), 1 mM/ 100 nL) or vehicle 10 min before RS session. The tail temperature was measured by an infrared thermal imager during the session. Twenty-four h after the RS session the rats were tested in the elevated plus maze (EPM). Conclusions/Significance: Inhibition of LSA neurotransmission reduced the MAP and HR increases observed during RS. However, no changes were observed in the decrease in skin temperature and increase in internal body temperature observed during this period. Also, LSA inhibition did not change the anxiogenic effect induced by RS observed 24 h later in the EPM. The present results suggest that LSA neurotransmission is involved in the cardiovascular but not the temperature and behavioral changes induced by restraint stress.
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Background: The bed nucleus of stria terminalis (BNST) is a limbic forebrain structure involved in hypothalamo-pituitary-adrenal axis regulation and stress adaptation. Inappropriate adaptation to stress is thought to compromise the organism's coping mechanisms, which have been implicated in the neurobiology of depression. However, the studies aimed at investigating BNST involvement in depression pathophysiology have yielded contradictory results. Therefore, the objective of the present study was to investigate the effects of temporary acute inactivation of synaptic transmission in the BNST by local microinjection of cobalt chloride (CoCl(2)) in rats subjected to the forced swimming test (FST). Methods: Rats implanted with cannulae aimed at the BNST were submitted to 15 min of forced swimming (pretest). Twenty- four hours later immobility time was registered in a new 5 min forced swimming session (test). Independent groups of rats received bilateral microinjections of CoCl(2) (1 mM/100 nL) before or immediately after pretest or before the test session. Additional groups received the same treatment and were submitted to the open field test to control for unspecific effects on locomotor behavior. Results: CoCl(2) injection into the BNST before either the pretest or test sessions reduced immobility in the FST, suggesting an antidepressant-like effect. No significant effect of CoCl(2) was observed when it was injected into the BNST immediately after pretest. In addition, no effect of BNST inactivation was observed in the open field test. Conclusion: These results suggest that acute reversible inactivation of synaptic transmission in the BNST facilitates adaptation to stress and induces antidepressant-like effects.
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Left ventricular hypertrophy (LVH) is a complication that may result from chronic hypertension. While nitric oxide (NO) deficiency has been associated with LVH, inconsistent results have been reported with regards to the association of endothelial NO synthase (eNOS) polymorphisms and LVH in hypertensive patients. This study aims to assess whether eNOS haplotypes are associated with LVH in hypertensive patients. This study included 101 healthy controls and 173 hypertensive patients submitted to echocardiography examination. Genotypes for three eNOS polymorphisms were determined: a single-nucleotide polymorphism in the promoter region (T-786C) and in exon 7 (Glu298Asp), and variable number of tandem repeats in intron 4. We found no significant association between eNOS genotypes and hypertension or with LVH (all p>0.05). However, while we found two eNOS haplotypes associated with variable risk of hypertension (all p<0.05), we found no significant associations between eNOS haplotypes and LVH (all p>0.05), even after adjustment in multiple linear regression analysis. These findings suggest that eNOS haplotypes that have been associated with variable susceptibility to hypertension were not associated with LVH in hypertensive patients. Further studies are necessary to examine whether other genes downstream may interact with eNOS polymorphisms and predispose to LVH in hypertensive patients.
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Background: Chronic pelvic pain (CPP) is a lower abdominal pain lasting at least 6 months, occurring continuously or intermittently and not associated exclusively with menstruation or intercourse. Although the musculoskeletal system has been found to be involved in CPP, few studies have assessed the contribution of posture in women with CPP. We aimed to determine if the frequency of postural changes was higher in women with CPP than healthy subjects. Methods: A case-control study included 108 women with CPP of more than 6 months' duration (CPP group) who consecutively attended at the Hospital of the University of Sao Paulo and 48 healthy female volunteers (control group). Postural assessment was noninvasive and performed in the standing position, with the reference points of Kendall used as normal parameters. Factors associated with CPP were assessed by logistic regression analysis. Results: Logistic regression showed that the independent factors associated with CPP were postural changes in the cervical spine (OR 4.1; 95% CI 1.6-10.7; p < 0.01) and scapulae (OR 2.9; 95% CI 1.1-7.6; p < 0.05). Conclusion: Musculoskeletal changes were associated with CPP in 34% of women. These findings suggest that a more detailed assessment of women with CPP is necessary for better diagnosis and for more effective treatment.
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Background: Detailed analysis of the dynamic interactions among biological, environmental, social, and economic factors that favour the spread of certain diseases is extremely useful for designing effective control strategies. Diseases like tuberculosis that kills somebody every 15 seconds in the world, require methods that take into account the disease dynamics to design truly efficient control and surveillance strategies. The usual and well established statistical approaches provide insights into the cause-effect relationships that favour disease transmission but they only estimate risk areas, spatial or temporal trends. Here we introduce a novel approach that allows figuring out the dynamical behaviour of the disease spreading. This information can subsequently be used to validate mathematical models of the dissemination process from which the underlying mechanisms that are responsible for this spreading could be inferred. Methodology/Principal Findings: The method presented here is based on the analysis of the spread of tuberculosis in a Brazilian endemic city during five consecutive years. The detailed analysis of the spatio-temporal correlation of the yearly geo-referenced data, using different characteristic times of the disease evolution, allowed us to trace the temporal path of the aetiological agent, to locate the sources of infection, and to characterize the dynamics of disease spreading. Consequently, the method also allowed for the identification of socio-economic factors that influence the process. Conclusions/Significance: The information obtained can contribute to more effective budget allocation, drug distribution and recruitment of human skilled resources, as well as guiding the design of vaccination programs. We propose that this novel strategy can also be applied to the evaluation of other diseases as well as other social processes.
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The most relevant clinical trials, assessing the role of glycemic control in reducing cardiovascular risk, are examined. The UKPDS was the first to address this issue. More recent trials (ACCORD, ADVANCE and VADT) are controversial and evidences did not support that strict glycemic control (reflected by normal glycated hemoglobin) exclusively is sufficient to reduce cardiovascular risk in complicated individuals with long-term type 2 diabetes mellitus. Some possible reasons for controversies are included.
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Pathogenicity of strains of the entomopathogenic fungus Beauveria bassiana and endophytic strains of Beauveria sp against the bovine tick Rhipicephalus (Boophilus) microplus was tested in laboratory bioassays and under field conditions. Suspensions containing 10(5), 10(7) and 10(9) conidia/mL were prepared of each fungal strain for laboratory bioassays. The ticks were maintained at 28 degrees C, 90 +/- 5% relative humidity, and the following variables were evaluated: initial female weight, egg weight, hatching percentage, reproductive efficiency, and percentage control. For tests under field conditions, a Beauveria suspension containing 10(6) conidia/mL was sprayed on tick-infested cows. After 72 h, the ticks were collected to estimate mortality under field conditions. Laboratory bioassays showed a mortality of 20 to 50% of the ticks seven days after inoculation with 10(7) Beauveria conidia/mL. Under field conditions 10(6) Beauveria conidia/mL induced 18-32% mortality. All Beauveria strains were effective in biological control of R. (Boophilus) microplus under laboratory and field test conditions. This is the first demonstration that endophytic fungi can be used for biological control of the cattle tick; this could help reduce environmental contamination by diminishing the need for chemical acaricides. Two endophytic strains were isolated from maize leaves and characterized by molecular sequencing of 5.8S rDNA ITS1 and ITS2 and morphological analyses of conidia. We found that these two endophytic Beauveria isolates, designated B95 and B157, are close to Beauveria amorpha.
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Marine turtles are increasingly being threatened worldwide by anthropogenic activities. Better understanding of their life cycle, behavior and population structure is imperative for the design of adequate conservation strategies. The mtDNA control region is a fast-evolving matrilineal marker that has been employed in the study of marine turtle populations. We developed and tested a simple molecular tracing system for Caretta caretta mtDNA haplotypes by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). Using this technique, we were able to distinguish the SSCP patterns of 18 individuals of the haplotypes CC-A4, CC-A24 and CCxLO, which are commonly found in turtles sampled on the Brazilian coast. When we analyzed 15 turtles with previously unknown sequences, we detected two other haplotypes, in addition to the other four. Based on DNA sequencing, they were identified as the CC-A17 and CC-A1 haplotypes. Further analyses were made with the sea turtles, Chelonia mydas (N = 8), Lepidochelys olivacea (N = 3) and Eretmochelys imbricata (N = 1), demonstrating that the PCR-SSCP technique is able to distinguish intra-and interspecific variation in the family Cheloniidae. We found that this technique can be useful for identifying sea turtle mtDNA haplotypes, reducing the need for sequencing.
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Background: Production of reactive oxygen species (ROS) due to chronic exposure to glucose has been associated with impaired beta cell function and diabetes. However, physiologically, beta cells are well equipped to deal with episodic glucose loads, to which they respond with a fine tuned glucose-stimulated insulin secretion (GSIS). In the present study, a systematic investigation in rat pancreatic islets about the changes in the redox environment induced by acute exposure to glucose was carried out. Methodology/Principal Findings: Short term incubations were performed in isolated rat pancreatic islets. Glucose dose- and time-dependently reduced the intracellular ROS content in pancreatic islets as assayed by fluorescence in a confocal microscope. This decrease was due to activation of pentose-phosphate pathway (PPP). Inhibition of PPP blunted the redox control as well as GSIS in a dose-dependent manner. The addition of low doses of ROS scavengers at high glucose concentration acutely improved beta cell function. The ROS scavenger N-acetyl-L-cysteine increased the intracellular calcium response to glucose that was associated with a small decrease in ROS content. Additionally, the presence of the hydrogen peroxide-specific scavenger catalase, in its membrane-permeable form, nearly doubled glucose metabolism. Interestingly, though an increase in GSIS was also observed, this did not match the effect on glucose metabolism. Conclusions: The control of ROS content via PPP activation by glucose importantly contributes to the mechanisms that couple the glucose stimulus to insulin secretion. Moreover, we identified intracellular hydrogen peroxide as an inhibitor of glucose metabolism intrinsic to rat pancreatic islets. These findings suggest that the intracellular adjustment of the redox environment by glucose plays an important role in the mechanism of GSIS.
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We present a derivation of the Redfield formalism for treating the dissipative dynamics of a time-dependent quantum system coupled to a classical environment. We compare such a formalism with the master equation approach where the environments are treated quantum mechanically. Focusing on a time-dependent spin-1/2 system we demonstrate the equivalence between both approaches by showing that they lead to the same Bloch equations and, as a consequence, to the same characteristic times T(1) and T(2) (associated with the longitudinal and transverse relaxations, respectively). These characteristic times are shown to be related to the operator-sum representation and the equivalent phenomenological-operator approach. Finally, we present a protocol to circumvent the decoherence processes due to the loss of energy (and thus, associated with T(1)). To this end, we simply associate the time dependence of the quantum system to an easily achieved modulated frequency. A possible implementation of the protocol is also proposed in the context of nuclear magnetic resonance.
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The persistent current in two vertically coupled quantum rings containing few electrons is studied. We find that the Coulomb interaction between the rings in the absence of tunneling affects the persistent current in each ring and the ground-state configurations. Quantum tunneling between the rings alters significantly the ground state and the persistent current in the system.
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Background: Worldwide distribution of surgical interventions is unequal. Developed countries account for the majority of surgeries and information about non-cardiac operations in developing countries is scarce. The purpose of our study was to describe the epidemiological data of non-cardiac surgeries performed in Brazil in the last years. Methods and Findings: This is a retrospective cohort study that investigated the time window from 1995 to 2007. We collected information from DATASUS, a national public health system database. The following variables were studied: number of surgeries, in-hospital expenses, blood transfusion related costs, length of stay and case fatality rates. The results were presented as sum, average and percentage. The trend analysis was performed by linear regression model. There were 32,659,513 non-cardiac surgeries performed in Brazil in thirteen years. An increment of 20.42% was observed in the number of surgeries in this period and nowadays nearly 3 million operations are performed annually. The cost of these procedures has increased tremendously in the last years. The increment of surgical cost was almost 200%. The total expenses related to surgical hospitalizations were more than $10 billion in all these years. The yearly cost of surgical procedures to public health system was more than $1.27 billion for all surgical hospitalizations, and in average, U$445.24 per surgical procedure. The total cost of blood transfusion was near $98 million in all years and annually approximately $10 million were spent in perioperative transfusion. The surgical mortality had an increment of 31.11% in the period. Actually, in 2007, the surgical mortality in Brazil was 1.77%. All the variables had a significant increment along the studied period: r square (r(2)) = 0.447 for the number of surgeries (P = 0.012), r(2) = 0.439 for in-hospital expenses (P = 0.014) and r(2) = 0.907 for surgical mortality (P = 0.0055). Conclusion: The volume of surgical procedures has increased substantially in Brazil through the past years. The expenditure related to these procedures and its mortality has also increased as the number of operations. Better planning of public health resource and strategies of investment are needed to supply the crescent demand of surgery in Brazil.
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This work presents a novel way to introduce gold nanoparticles (Au NPs) in a multilayer polymer produced by the layer-by-layer (LbL) assembling technique. The technique chosen shows that, depending on the pH used, different morphological structures can be obtained from monolayer or bilayer Au NPs. The MEIS and RBS techniques allowed for the modelling of the interface polymer-NPs, as well as the understanding of the interaction of LbL system, when adjusting the pH in weak polyelectrolytes. The process reveals that the optical properties of multilayer systems could be fine-tuned by controlling the addition of metallic nanoparticles, which could also modify specific polarization responses.
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Cardiovascular responses elicited by the stimulation of kinin B2 receptors in the IV cerebral ventricle paratrigeminal nucleus or in the thoracic spinal cord are similar to those observed during an exercise bout Considering that the kalikrein-kinin system (KKS) could act on the cardiovascular modulation during behavioral responses as physical exercise or stress this study evaluated the central B2 receptor densities of Wistar (W) and spontani ously hypertensive rats (SHR) after chronic moderate exercise Animals we re exercise-trained for ten weeks on a treadmill Afterwards systolic blood pressure decreased in both trained strains Animals were killed and the medulla and spinal cord extracted for B2 receptor autoradiography Trained animals were compared to their sedentary controls Sedentary groups showed specific binding sites for Hoe-140 (fmol/mg of tissue) in laminas 1 and 2 of the spinal cord nucleus of the solitary tract (NTS) area postrema (AP) spinal trigeminal tract (sp5) and paratrigeminal nucleus (Pa5) In trained W a significant increase (p<0 05) in specific binding was observed in the Pa5 (31 3%) and NTS (28 2%) Trained SHR showed a significant decrease in n ceptor density in lamina 2 (21 9%) of the thoracic spinal cord and an increase in specific binding in Pa5 (36 1%) We suggest that in the medulla chronic exercise could hyper stimulate the KKS enhancing their efficiency through the increase of B2 receptor density involving this receptor in central cardiovascular control during exercise or stress In the lamina 2 B2 receptor might be involved in the exercise-induced hypotension (C) 2010 Elsevier BV All rights reserved
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Thyroid hormone receptor beta (TR beta also listed as THRB oil the MGI Database)-selective agonists activate brown adipose tissue (BAT) thermogenesis, while only minimally affecting cardiac activity or lean body mass. Here, we tested the hypothesis that daily administration of the TR beta agonist GC-24 prevents the metabolic alterations associated with a hypercaloric diet. Rats were placed on a high-fat diet and after a month exhibited increased body weight (BW) and adiposity, fasting hyperglycemia and glucose intolerance, increased plasma levels of triglycerides, cholesterol, nonesterified Fatty acids and interleukin-6. While GC-24 administration to these animals did not affect food ingestion or modified the progression of BW gain, it did increase energy, g the increase in adiposity Without expenditure, eliminating causing cardiac hypertrophy Fasting hyperglycemia remained unchanged, but treatment with GC-24 improved glucose I tolerance by increasing insulin Sensitivity and also normalized plasma triglyceride levels. plasma cholesterol levels were only Partially normalized and liver cholesterol content remained high in the GC-24-treated animals. Gene expression in liver, skeletal muscle, and white adipose tissue was only minimally affected by treatment with GC-24, with the main target being BAT In conclusion, during high-fat feeding treatment with the TR beta-selective agonist, GC-24 only partially improves metabolic control probably as a result Of accelerating the resting metabolic rate. Journal of Endocrinology (2009) 203, 291-299