Thermoregulatory responses of Alpine goats during thermal stress

Eight non-lactating Alpine goats, averaging 57kg, were paired according to weight and assigned randomly to 2 groups of 4 animals, control (CG) and treatment (TG) with feed and water ad libitum. An adjustment period of 7 days with all animals at thermoneutral conditions was followed by a 28-day period when TG was exposed to air temperatures averaging 35.0 degrees C, from 0800 to 1700h, including simulated solar radiation, and thermoneutral conditions from 2700 to 0800h. CG remained under thermoneutral conditions. Respiratory frequency was greater, tidal volume lower, and respiratory minute volume greater for TG than CG (176 vs 30 breaths/min, P<.001, 105 vs 293ml, P<.01; 18.4 vs 9.21, P<.05). Respiratory evaporation and sweating rate as well as rectal and skin temperatures were greater for TG than CG (14.59 vs 6.32 kcal h(-1), P<.01; 43.97 vs.00 g m(-2) h(-1), P<.001; 40.0 vs 38.9 degrees C, P<.001; 39.3 vs 35.8 degrees C, P<.01). There was no difference between groups for hematocrit and feed intake, but water consumption was greater for stressed goats than control ones (28.3 vs 29.7%; 1.44 vs 1.49 kg/day; 3.07 vs 1.26 I/day, P<.05), Final body weights of both groups were similar to initial ones. It was concluded that non-lactating goats tolerated well a 35 degrees C day temperature which is 5 degrees C above the upper critical temperature, with a black-globe temperature of 39.1 degrees C and a Botsball temperature of 28.3 degrees C, though a certain degree of hyperthermia may occur, as long as thermoneutral conditions have prevailed during the night.

Water regulation of actinomycin-D binding to DNA: the interplay among drug affinity, DNA long-range conformation, and hydration

Actiaomycin-D (actD) binds to natural DNA at two different classes of binding sites, weak and strong. The affinity for these sites is highly dependent on DNA se(sequence and solution conditions, and the interaction appears to be purely entropic driven Although the entropic character of this reaction has been attributed to the release of water molecules upon drug to DNA complex formation, the mechanism by which hydration regulates actD binding and discrimination between different classes of binding sites on natural DNA is still unknown. In this work, we investigate the role of hydration on this reaction using the osmotic stress method. We skew that the decrease of solution water activity, due to the addition of sucrose, glycerol ethylene glycol, and betaine, favors drug binding to the strong binding sites on DNA by increasing both the apparent binding affinity Delta G, and the number of DNA base pairs apparently occupied by the bound drug n(bp/actD). These binding parameters vary linearly with the logarithm of the molar fraction of water in solution log(X-w), which indicates the contribution of water binding to the energetic of the reaction. It is demonstrated that the hydration change measured upon binding increases proportionally to the apparent size of the binding site n(bp/uctD). This indicates that n(bp/actD) measured from the Scatchard plod is a measure of the size of the DNA molecule changing conformation due to ligand binding. We also find that the contribution of DNA deformation, gauged by n(bp/act) to the total free energy of binding Delta G, is given by Delta G = Delta G(local) + n(bp/actD) x delta G(DNA), where Delta G(local), = -8020 +/- 51 cal/mol of actD bound and delta G(DNa) = -24.1 +/- 1.7cal/mol of base pair at 25 degrees C. We interpret Delta G(local), as the energetic contribution due to the direct interactions of actD with the actual tetranucleotide binding site, and it n(bp/actB) X delta G(DNA) as that due to change inconformation, induced by binding, of it n(bp/actD) DNA base pairs flanking the local site. This interpretation is supported by the agreement found between the value of delta G(DNA) and the torsional free energy change measured independently. We conclude suggesting an allosteric model for ligand binding to DNA, such that the increase in binding affinity is achieved by increasing the relaxation of the unfavorable free energy of binding storage at the local site through a larger number of DNA base pairs. The new aspect on this model is that the size of the complex is not fixed but determined by solutions conditions, such as water activity, which modulate the energetic barrier to change helix conformation. These results may suggest that long-range allosteric transitions of duplex DNA are involved in the inhibition of RNA synthesis by actD, and more generally, in the regulation of transcription. (C) 2000 John Wiley & Sons, Inc.

Calorimetry, Morphometry, Oxidative Stress, and Cardiac Metabolic Response to Growth Hormone Treatment in Obese and Aged Rats

This study investigated the effects of growth hormone therapy on energy expenditure, lipid profile, oxidative stress and cardiac energy metabolism in aging and obesity conditions. Life expectancy is increasing in world population and with it, the incidence of public health problems such as obesity and cardiac alterations. Because growth hormone (GH) concentration is referred to be decreased in aging conditions, a question must be addressed: what is the effect of GH on aging related adverse changes? To investigate the effects of GH on cardiac energy metabolism and its association with calorimetric parameters, lipid profile and oxidative stress in aged and obese rats, initially 32 male Wistar rats were divided into 2 groups (n = 16), C: given standard-chow and water; H: given hypercaloric-chow and receiving 30 % sucrose in its drinking water. After 45 days, both C and H groups were divided into 2 subgroups (n = 8), C + PL: standard-chow, water, and receiving saline subcutaneously; C + GH: standard-chow, water, and receiving 2 mg/kg/day rhGH subcutaneously; H + PL: hypercaloric-chow, 30 % sucrose, receiving saline subcutaneously; H + GH: hypercaloric-chow, 30 % sucrose, receiving rhGH subcutaneously. After 30 days, C + GH and H + PL rats had higher body mass index, Lee-index, body fat content, percent-adiposity, serum triacylglycerol, cardiac lipid-hydroperoxide, and triacylglycerol than C + PL. Energy-expenditure (RMR)/body weight, oxygen consumption and fat-oxidation were higher in H + GH than in H + PL. LDL-cholesterol was highest in H + GH rats, whereas cardiac pyruvate-dehydrogenase and phosphofrutokinase were higher in H + GH and H + PL rats than in C + PL. In conclusion, the present study brought new insights on aging and obesity, demonstrating for the first time that GH therapy was harmful in aged and obesity conditions, impairing calorimetric parameters and lipid profile. GH was disadvantageous in control old rats, having undesirable effects on triacylglycerol accumulation and cardiac oxidative stress.

Use of levoglucosan, potassium, and water-soluble organic carbon to characterize the origins of biomass-burning aerosols

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

Rheological Analysis of Water Clay Compositions in Order to Investigate Mudflows Developing in Canals

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

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)

The primary sources of carbon loss during the crop-establishment period in a subtropical Oxisol under contrasting tillage systems

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

An animal model for the study of Chamomilla in stress and depression: pilot study

The behavioral and hematological effects of treatment with Chamomilla 6cH in mice subjected to experimental stress are described. Swiss mice were randomly divided into pairs, one animal was inoculated with Ehrlich's tumor, the other was treated daily with Chamomilla 6cH or control or received no treatment. After 7 days, the animals were observed in an open-field arena and blood samples taken. Mice who cohabitated with a sick cage-mate showed a decrease in their general activity, but those treated with Chamomilla 6cH were less severely affected (p = 0.0426). No hematologicall changes were observed.In a second experiment, the forced swimming test was applied to mice pre-treated with Chamomilla 6cH, controls were: water, 10% ethanol or amitriptyline. Only the amitriptyline and ethanol treated groups showed significant excitatory behavior (p = 0.0020), Chamomilla 6cH treated animals' scores intermediate between water control and ethanol or amitriptyline. A decrease in the leukocyte count was observed in the amitriptyline and Chamomilla 6cH treated groups (p = 0.039). These data suggest that treatment with Chamomilla 6cH is related to the recovery of basal behavioral conditions in mice subjected to stressful conditions.

Resveratrol toxicity: Effects on risk factors for atherosclerosis and hepatic oxidative stress in standard and high-fat diets

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Conjugated linoleic acid and cardiac health: Oxidative stress and energetic metabolism in standard and sucrose-rich diets

Studies on conjugated linoleic acid ingestion and its effect on cardiac tissue are necessary for the safe utilization of this compound as supplement for weight loss. Male Wistar 24-rats were divided into four groups (n = 6):(C)given standard chow, water and 0.5 ml saline, twice a week by gavage; (C-CLA)receiving standard chow, water and 0.5 ml of conjugated linoleic acid, twice a week, by gavage; (S)given standard chow, saline by gavage, and 30% sucrose in its drinking water; (S-CLA)receiving standard chow, 30% sucrose in its drinking water and conjugated linoleic acid. After 42 days of treatment S rats had obesity with increased abdominal-circumference, dyslipidemia, oxidative stress and myocardial lower citrate synthase(CS) and higher lactate dehydrogenase(LDH) activities than C. Conjugated linoleic acid had no effects on morphometric parameters in C-CLA, as compared to C, but normalized morphometric parameters comparing S-CLA with S. There was a negative correlation between abdominal adiposity and resting metabolic rate. Conjugated linoleic acid effect, enhancing fasting-VO2/surface area, postprandial-carbohydrate oxidation and serum lipid hydroperoxide resembled to that of the S group. Conjugated linoleic acid induced cardiac oxidative stress in both fed conditions, and triacylglycerol accumulation in S-CLA rats. Conjugated linoleic acid depressed myocardial LDH comparing C-CLA with C, and beta-hydroxyacyl-coenzyme-A dehydrogenase/CS ratio, comparing S-CLA with S. In conclusion, dietary conjugated linoleic acid supplementation for weight loss can have long-term effects on cardiac health. Conjugated linoleic acid, isomers c9, t11 and t10, c12 presented undesirable pro-oxidant effect and induced metabolic changes in cardiac tissue. Nevertheless, despite its effect on abdominal adiposity in sucrose-rich diet condition, conjugated linoleic acid may be disadvantageous because it can lead to oxidative stress and dyslipidemic profile. (c) 2007 Elsevier B.V All rights reserved.

Uniaxial stress relaxation measurement in fluoroindate glasses

Glasses of composition 40InF3-20SrF2-16BaF2-20ZnF 2-2GdF3-2NaF (mol%) have been prepared under controlled atmosphere. The time response of the stresses under the application of a constant strain was determined by microellipsometer technique, performed in ambient atmosphere at T < Tg = 294°C. The glasses show a Newtonian behavior at small stress level. During the relaxation process, very small grooves perpendicular to the applied strain appeared on the glass surface and affected its behavior after a time. The formation of these grooves is associated with the ambient atmosphere. Measurements in dry atmosphere showed that humidity was an important parameter in the relaxation process.

Water sorption, solubility, and bond strength of two autopolymerizing acrylic resins and one heat-polymerizing acrylic resin.

STATEMENT OF PROBLEM: Because water sorption of autopolymerizing acrylic reline resins is accompanied by volumetric change, it is a physical property of importance. As residual monomer leaches into the oral fluids and causes tissue irritation, low solubility of these resins is desired. Another requirement is a satisfactory bond between the autopolymerizing acrylic resins and the denture base acrylic resin. PURPOSE: This study compared the water sorption, solubility, and the transverse bond strength of 2 autopolymerizing acrylic resins (Duraliner II and Kooliner) and 1 heat-polymerizing acrylic resin (Lucitone 550). MATERIAL AND METHODS: The water sorption and solubility test was performed as per International Standards Organization Specification No. 1567 for denture base polymers. Bond strengths between the autopolymerizing acrylic resins and the heat-polymerizing acrylic resin were determine with a 3-point loading test made on specimens immersed in distilled water at 37 degrees C for 50 hours and for 30 days. Visual inspection determined whether failures were adhesive or cohesive. RESULTS: Duraliner II acrylic resin showed significantly lower water sorption than Kooliner and Lucitone 550 acrylic resins. No difference was noted in the solubility of all materials. Kooliner acrylic resin demonstrated significantly lower transverse bond strength to denture base acrylic resin and failed adhesively. The failures seen with Duraliner II acrylic resin were primarily cohesive in nature. CONCLUSIONS: Autopolymerizing acrylic reline resins met water sorption and solubility requirements. However, Kooliner acrylic resin demonstrated significantly lower bond strength to denture base acrylic resin.

Chronic mild prenatal stress exacerbates the allergen-induced airway inflammation in rats

The effects of chronic mild prenatal stress on leukocyte infiltration into the airways was investigated in rat offspring. The chronic prenatal stress consisted of transitory and variable changes in the rat's living conditions. Offspring at adult age were actively sensitized (day 0) and intratracheally challenged (day 14) with ovalbumin. Bronchoalveolar lavage was performed in the offspring at 48 h after intratracheal challenge with ovalbumin. A significant increase in total leukocyte infiltration was observed in the non-stressed offspring group and this was associated with a marked recruitment of eosinophils without a significant effect on the influx of neutrophils and mononuclear cells. In the prenatal stressed offspring, the counts of both total leukocyte and eosinophils, as well as mononuclear cells, was increased by 50% compared to the non-stressed offspring. We provide here the first experimental evidence that chronic mild unpredictable prenatal stress produces a marked increase in the allergen-induced airway inflammation in the rat offspring.

Effect of fish density during transportation on stress and mortality of juvenile Tambaqui Colossoma macropomum

The increased demand for juvenile tambaqui Colossoma macropomum for grow-out ponds and stocking programs in the Amazon state of Brazil has increased the transportation of this species. This study was designed to determine the optimum density of juvenile tambaqui during transportation in closed containers. Fish (51.9 ± 3.3 g and 14.9 ± 0.4 cm) were packed in sealed plastic bags and transported for 10 h at four densities: 78, 156, 234, and 312 kg/m3. After transportation, fish from each density were kept in separate 500-L tanks for 96 h. Mortality, 96-h cumulative mortality, water quality, and blood parameters (hematocrit, plasma cortisol, and glucose) were monitored. Fish mortality after transportation was significantly lower at densities of 78 and 156 kg/m3 than at 234 and 312 kg/m3. Cumulative mortality was significantly lower at a density of 78 kg/m3. Dissolved oxygen after 10 h of transportation remained high at a density of 78 kg/m3, but reached critically low values at all other densities. Ammonia concentration was highest at the lowest density and was lower at higher densities. Carbon dioxide concentration was lowest at the density of 78 kg/m3 but higher in the other treatments. Plasma glucose and cortisol increased significantly immediately after transportation at densities of 156, 234, and 312 kg/m3, returning to control values by 24 h. The best density for juvenile tambaqui during a 10-h transportation haul in a closed container was 78 kg/m3. At this density there was no fish mortality, water quality was kept within acceptable values, and fish were not stressed.

Physiological responses associated with capture and crowding stress in matrinxã Brycon cephalus (Gunther, 1869)

The dynamics of plasma cortisol, blood glucose, plasma chloride and liver glycogen were investigated in matrinxã (Brycon cephalus) submitted to capture and various periods of crowding. A total of 400 fish (700 ± 22 g weight) were distributed in four ponds divided into four 50-m2 squares (25 fish/square, 350 gL-1), where they were acclimated for 30 days. On the sampling day, after 24 h without food, all fish from three squares were transferred to the fourth square. Six fish were sampled before the procedure (control group, zero time) and 1, 3, 6 and 24 h after the capture and crowding. Each sampling was performed in a different pond to prevent additional stress. Fish were anaesthetized and blood and liver collected for biochemical analysis. Water temperature, pH, dissolved oxygen, alkalinity, ammonia and nitrite levels were within acceptable levels for matrinxã rearing. Slight but not significant increases were verified in plasma cortisol and blood glucose levels, as were decreases in plasma chloride and liver glycogen levels. The results suggest that matrinxã is highly tolerant to the procedures of capture and short-term crowding.