Toxin jararhagin in low doses induces interstitial edema and increases the metabolic rate and red blood cells in mice

Jararhagin is a metalloproteinase from Bothrops jararaca responsible for hemorrhage, inflammation, necrosis and edema. Effects of low doses of the toxin were analyzed on the energy metabolism of mice as well as its physiological implications. Measures of O-2 consumption (VO2) were quantified after 4 and 24 h of the jarathagin administration during four weeks. Hematocrit and histology of the lungs were also analyzed after the end of the treatment. Results showed that animals that received subcutaneous doses of jararhagin had significant increase in VO2 from second (120 ng) and third weeks (60 ng) after 4 and 24 h, comparing to control, as well as in the number of erythrocytes after four weeks. Histology of the lungs showed interstitial edema within the alveolar septum. Results suggest that the jararhagin toxin caused an increase in VO2 and edema of intra-alveolar septum. The increase of the erythrocytes could be a physiological response to adjust the higher necessity of oxygen, due to diffusional abnormalities caused by the edema. Thus, low doses of jararhagin promote endothelial edema which lead to changes in several physiological conditions. (c) 2006 Elsevier Ltd. All rights reserved.

Effects of season, temperature, and body mass on the standard metabolic rate of tegu lizards (Tupinambis merianae)

This study examined how the standard metabolic rate of tegu lizards, a species that undergoes large ontogenetic changes in body weight with associated changes in life-history traits, is affected by changes in body mass, body temperature, season, and life-history traits. We measured rates of oxygen consumption ((V) over dot o(2)) in 90 individuals ranging in body mass from 10.4. g to 3.75 kg at three experimental temperatures ( 17 degrees, 25 degrees, and 30 degrees C) over the four seasons. We found that standard metabolic rate scaled to the power of 0.84 of body mass at all experimental temperatures in all seasons and that thermal sensitivity of metabolism was relatively low (Q(10) approximate to 2.0-2.5) over the range from 17 degrees to 30 degrees C regardless of body size or season. Metabolic rates did vary seasonally, being higher in spring and summer than in autumn and winter at the same temperatures, and this was true regardless of animal size. Finally, in this study, the changes in life-history traits that occurred ontogenetically were not accompanied by significant changes in metabolic rate.

Studies on the respiration rate of free and immobilized cells of Cephalosporium acremonium in cephalosporin C production

Bioprocesses using filamentous fungi immobilized in inert supports present many advantages when compared to conventional free cell processes. However, assessment of the real advantages of the unconventional process demands a rigorous study of the limitations to diffusional mass transfer of the reagents, especially concerning oxygen. In this work, a comparative study was carried out on the cephalosporin C production process in defined medium containing glucose and sucrose as main carbon and energy sources, by free and immobilized cells of Cephalosporium acremonium ATCC 48272 in calcium alginate gel beads containing alumina. The effective diffusivity of oxygen through the gel beads and the effectiveness factors related to the respiration rate of the microorganism were determined experimentally. By applying Monod kinetics, the respiration kinetics parameters were experimentally determined in independent experiments in a complete production medium. The effectiveness factor experimental values presented good agreement with the theoretical values of the approximated zero-order effectiveness factor, considering the dead core model. Furthermore, experimental results obtained with immobilized cells in a 1.7-L tower bioreactor were compared with those obtained in 5-L conventional fermenter with free cells. It could be concluded that it is possible to attain rather high production rates working with relatively large diameter gel beads (ca. 2.5 mm) and sucrose consumption-based productivity was remarkably higher with immobilized cells, i.e., 0.33 gCPC/kg sucrose/h against 0.24 gCPC/kg sucrose/h in the aerated stirred tank bioreactor process. (C) 1999 John Wiley & Sons, Inc.

Effects of Cold Water Immersion and Active Recovery on Post-Exercise Heart Rate Variability

The aim of the present study was to investigate the potential benefits of cold water immersion (CWI) and active recovery (AR) on blood lactate concentration ([Lac]) and heart rate variability (HRV) indices following high-intensity exercise. 20 male subjects were recruited. on the first visit, an incremental test was performed to determine maximal oxygen consumption and the associated speed (MAS). The remaining 3 visits for the performance of constant velocity exhaustive tests at MAS and different recovery methods (6 min) were separated by 7-day intervals [randomized: CWI, AR or passive recovery (PR)]. The CWI and AR lowered [Lac] (p < 0.05) at 11, 13 and 15 min after exercise cessation in comparison to PR. There was a 'time' and 'recovery mode' interaction for 2 HRV indices: standard deviation of normal R-R intervals (SDNN) (partial eta squared = 0.114) and natural log of low-frequency power density (lnLF) (partial eta squared = 0.090). CWI presented significantly higher SDNN compared to PR at 15 min of recovery (p < 0.05). In addition, greater SDNN values were found in CWI vs. AR during the application of recovery interventions, and at 30 and 75 min post-exercise (p < 0.05 for all differences). The lnLF during the recovery interventions and at 75 min post-exercise was greater using CWI compared with AR (p < 0.05). For square root of the mean of the sum of the squares of differences between adjacent R-R intervals (RMSSD) and natural log of high-frequency power density (lnHF), a moderate effect size was found between CWI and PR during the recovery interventions and at 15 min post-exercise. Our findings show that AR and CWI offer benefits regarding the removal of [Lac] following high-intensity exercise. While limited, CWI results in some improvement in post-exercise cardiac autonomic regulation compared to AR and PR. Further, AR is not recommended if the aim is to accelerate the parasympathetic reactivation.

Weekend ethanol consumption and high-sucrose diet: resveratrol effects on energy expenditure, substrate oxidation, lipid profile, oxidative stress and hepatic energy metabolism

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

Energy Expenditure and Oxygen Consumption as Novel Biomarkers of Obesity-induced Cardiac Disease in Rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Oxygen consumption of the amphibious snail Pomacea lineata; Influence of weight, sex and environments

1. 1. Under normoxic conditions at 25°C Pomacea lineata, free to move into or out of water, showed an increase in O2 consumption with increase in body size (dry wt), the slope of the log-log plot of these two parameters being b = 0.76. 2. 2. The metabolic rate decreased with weight. 3. 3. Males and females in a sexually receptive state did not exhibit significantly different QO2 values. 4. 4. The metabolic rates of animals when under water using ctenidium did not differ significantly from when out of water using the lung. © 1981.

Permanent Magnet Hall Thruster for satellite orbit raising with low power energy consumption

Electric propulsion is now a succeful method for primary propulsion of deep space long duration missions and for geosyncronous satellite attitude control. Closed Drift Thruster, so called Hall Thruster or SPT (Stationary Plasma Thruster), was primarily conceived in USSR (the ancient Soviet Union) and, since then, it has been developed by space agencies, space research institutes and industries in several countries such as France, USA, Israel, Russian Federation and Brazil. In this work we present the main features of the Permanent Magnet Hall Thruster (PMHT) developed at the Plasma Laboratory of the University of Brasilia. The idea of using an array of permanent magnets, instead of an electromagnet, to produce a radial magnetic field inside the plasma channel of the thruster is very significant. It allows the development of a Hall Thruster with power consumption low enough to be used in small and medium size satellites. Description of a new vacuum chamber used to test the second prototype of the PMHT (PHALL II) will be given. PHALL II has an aluminum plasma chamber and is smaller with 15 cm diameter and will contain rare earth magnets. We will show plasma density and temperature space profiles inside and outside the thruster channel. Ion temperature measurements based on Doppler broadening of spectral lines and ion energy measurements are also shown. Based on the measured plasma parameters we constructed an aptitude figure of the PMHT. It contains the specific impulse, total thrust, propellant flow rate and power consumption necessary for orbit raising of satellites. Based on previous studies of geosyncronous satellite orbit positioning we perform numerical simulations of satellite orbit raising from an altitude of 700 km to 36000 km using a PMHT operating in the 100 mN - 500 mN thrust range. In order to perform these calculations integration techniques were used. The main simulation paraters were orbit raising time, fuel mass, total satellite mass, thrust and exaust velocity. We conclude comparing our results with results obtainned with known space missions performed with Hall Thrusters. © 2008 by the American Institute of Aeronautics and Astronautics, Inc.

The effect of eccentric strength training on heart rate and on its variability during isometric exercise in healthy older men

The purpose of this study was to investigate if chronic eccentric strength training (ST) affects heart rate (HR) and heart rate variability (HRV) during sub-maximal isometric voluntary contractions (SIVC). The training group (TG) (9 men, 62 ± 2) was submitted to ST (12 weeks, 2 days/week, 2 - 4 sets of 8-12 repetitions at 75-80% peak torque (PT). The control group (CG) (8 men, 64 ± 4) did not perform ST. The HR and the HRV (RMSSD index) were evaluated during SIVC of the knee extension (15, 30 and 40% of PT). ST increased the eccentric torque only in TG, but did not change the isometric PT and the duration of SIVC. During SIVC, the HR response pattern and the RMSSD index were similar for both groups in pre- and post-training evaluations. Although ST increased the eccentric torque in the TG, it did not generate changes in HR or HRV. © Springer-Verlag 2008.

Electrogravimetric Analysis by Quartz-Crystal Microbalance on the Consumption of the Neurotransmitter Acetylcholine by Acetylcholinesterase

Electrogravimetric analysis was performed on the consumption of the neurotransmitter Acetylcholine (ACh) by Acetylcholinesterase (AChE) in situ and in real time. Michaelis-Menten assumption was achieved by using an enzyme micro-reactor in which the total enzyme was anchored in a quartz crystal microbalance chip (QCM-chip) with a strategically engineered self-assembled monolayer (SAM) of alkanethiols, which can prevent diffusion-controlled or spatially restricted kinetics. The real-time frequency changes indicated the rate of the products formation from enzymatic reaction. The QCM-chip was tested showing that it could demonstrate AChE inhibition by physostigmine. © 2013 Copyright Taylor and Francis Group, LLC.

Resting heart rate: Its correlations and potential for screening metabolic dysfunctions in adolescents

Background: In pediatric populations, the use of resting heart rate as a health index remains unclear, mainly in epidemiological settings. The aims of this study were to analyze the impact of resting heart rate on screening dyslipidemia and high blood glucose and also to identify its significance in pediatric populations.Methods: The sample was composed of 971 randomly selected adolescents aged 11 to 17 years (410 boys and 561 girls). Resting heart rate was measured with oscillometric devices using two types of cuffs according to the arm circumference. Biochemical parameters triglycerides, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and glucose were measured. Body fatness, sleep, smoking, alcohol consumption and cardiorespiratory fitness were analyzed.Results: Resting heart rate was positively related to higher sleep quality (β = 0.005, p = 0.039) and negatively related to cardiorespiratory fitness (β = -0.207, p = 0.001). The receiver operating characteristic curve indicated significant potential for resting heart rate in the screening of adolescents at increased values of fasting glucose (area under curve = 0.611 ± 0.039 [0.534 - 0.688]) and triglycerides (area under curve = 0.618 ± 0.044 [0.531 - 0.705]).Conclusion: High resting heart rate constitutes a significant and independent risk related to dyslipidemia and high blood glucose in pediatric populations. Sleep and cardiorespiratory fitness are two important determinants of the resting heart rate. © 2013 Fernandes et al.; licensee BioMed Central Ltd.

Time-course of neuroendocrine changes and its correlation with hypertension induced by ethanol consumption

Ethanol (ETOH) consumption has been associated with endocrine and autonomic changes, including the development of hypertension. However, the sequence of pathophysiological events underlying the emergence of this effect is poorly understood. Aims: This study aimed to establish a time-course correlation between neuroendocrine and cardiovascular changes contributing to the development of hypertension following ETOH consumption. Methods: Male adult Wistar rats were subjected to the intake of increasing ETOH concentrations in their drinking water (first week: 5%, second week: 10%, third and fourth weeks: 20% v/v). Results: ETOH consumption decreased plasma and urinary volumes, as well as body weight and fluid intake. Furthermore, plasma osmolality, plasma sodium and urinary osmolality were elevated in the ETOH-treated rats. ETOH intake also induced a progressive increase in the mean arterial pressure (MAP), without affecting heart rate. Initially, this increasein MAP was correlated with increased plasma concentrations of adrenaline and noradrenaline. After the second week of ETOH treatment, plasma catecholamines returned to basal levels, and incremental increases were observed in plasma concentrations of vasopressin (AVP) and angiotensin II (ANG II). Conversely, plasma oxytocin, atrial natriuretic peptide, prolactin and the hypothalamus-pituitary-adrenal axis components were not significantly altered by ETOH. Conclusions: Taken together, these results suggest that increased sympathetic activity may contribute to the early increase in MAP observed inETOHtreated rats. However, the maintenance of this effect may be predominantly regulated by the long-term increase in the secretion of other circulating factors, such as AVP and ANG II, the secretion of both hormones being stimulated by the ETOH-induced dehydration. © The Author 2013. Medical Council on Alcohol and Oxford University Press. All rights reserved.

Effects of constant rate infusion of anesthetic or analgesic drugs on general anesthesia with isoflurane: A retrospective study in 200 dogs

Constant rate infusion (CRI) shows several advantages in balanced anesthesia, such as reduction of requirement for inhaled anesthetics and control of pain. The most commonly used drugs in these protocols are local anesthetics, dissociative, and opioids, which may be administered alone or in combinations. We evaluated the records of 200 dogs that underwent various surgical procedures with anesthetic or analgesic CRI in the perioperative period during 2011 and 2012 at the Veterinary Hospital of Franca University (Unifran), and identified possible complications during the transoperative period. Records evaluated included clinical state, laboratory tests, drugs used in premedication and induction, and CRI protocol. Acepromazine and morphine were the main drugs used in premedication. Propofol was used to induce anesthesia alone or in combination with other agents. We evaluated records of the 25 different CRI protocols. Fentanyl was the main drug employed in CRI, either alone or in combination. There were 128 episodes of anesthetic complications during CRI;the most common were hypotension, hypertension, and tachycardia, which occurred in 43 (32%), 35 (26.3%), and 19 (14.2%) dogs, respectively. Cardiac arrhythmia was reported in only 4 dogs. Signs of respiratory depression were present in dogs treated with 6 different CRI protocols. The consumption of isoflurane (vol %) reduced between 15.7% and 21.05% after 30minutes of the CRI in the fentanyl and fentanyl-lidocaine-ketamine CRI groups (p<0.05). In conclusion, CRI is a valid component of balanced anesthesia in dogs, safe, and has a low incidence of adverse effects. However, future studies are warranted to describe the results of the clinical use of CRI to better characterize and refine this technique.

Steelhead trout Oncorhynchus mykiss metabolic rate is affected by dietary Aloe vera inclusion but not by mounting an immune response against formalin-killed Aeromonas salmonicida

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The benefits of soft sensor and multi-rate control for the implementation of wireless networked control systems

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