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V Pereira

Publications and source records attributed to V Pereira.

At least 19 recordsLinked to original sources
PubMed2006

Role of the central opioid system in the inhibition of water and salt intake induced by central administration of IL-1beta in rats.

In the present study we investigated, the effect of third ventricle injections of IL-1beta on water and salt intake in fluid-deprived and sodium-depleted rats. Central administration of IL-1beta significantly reduced water and salt intake in fluid-deprived animals and decreased salt intake in sodium-depleted rats. The antidipsogenic and antinatriorexic effects elicited by the central administration of IL-1beta were suppressed by pretreatment with central injections of the non-selective opioid antagonist naloxone (10 mug) in the two different experimental protocols used here (water deprivation and sodium depletion). In addition, central administration of IL-1beta failed to modify the intake of a 0.1% saccharin solution when the animals were submitted to a "dessert test" or to induce any significant locomotor deficit in the open-field test. The present results suggest that the activation of the central interleukinergic component by IL-1beta impairs the increase in water and salt intake induced by water deprivation and the enhancement in sodium appetite that follows sodium depletion. The data also support the conclusion that the antidipsogenic and antinatriorexic effects resulting from the activation of the central interleukinergic component rely on an opioid-dependent, naloxone-blockable system.

Animals↗
PubMed2006

Inhibition of water intake by the central administration of IL-1beta in rats: role of the central opioid system.

In the present study we investigated, the effect of third ventricle injections of IL-1beta on water intake, in rats, induced by three different physiological stimuli: dehydration induced by water deprivation, hypernatremia associated with hyperosmolarity induced by intragastric salt load, and hypovolemia produced by subcutaneous polytethyleneglycol administration. Central administration of IL-1beta at the doses of 4 and 8 ng reduced water intake in all three conditions studied. Third ventricle injections of IL-1beta (8 ng) were unable to diminish water intake in the groups of rats pretreated with central injections of the non-selective opioid antagonist naloxone (10 microg) in the three different conditions studied. Furthermore, the central administration of IL-1beta was neither able to modify the intake of a 0.1% saccharin solution when the animals were submitted to a "dessert test" nor to induce any significant locomotor deficit in the open-field test. These results suggest that the central activation of interleukin-1 receptors by IL-1beta is able to impair the thirst-inducing mechanisms triggered by the physiological stimuli represented by dehydration, hyperosmolarity and hypovolemia. These results lead us to conclude that the antidipsogenic effects observed following central administration of IL-1beta require the functional integrity of the brain opiatergic system.

Animals↗
PubMed2006

Influence of grain processing on acid-base balance in feedlot steers.

Grain processing (e.g. grinding, steaming, pelleting, flaking) has been reported to modify the incidence of ruminal disturbances in feedlot cattle. This study investigated the effects of two grain processing methods widely used in Spanish feedlots (grinding and pelleting) on animal performance, blood acid-base balance, blood electrolyte levels and serum lactate in a 140-day feedlot experiment with double-muscled Belgian Blue steers. The main aim of the study was to evaluate the way in which these two feeds modify blood acid-base balance, which is closely associated with ruminal pH. In light of our results we conclude that the animals that received the pelleted feed showed a more stable acid-base balance over time than those fed a ground feed. Nevertheless, higher levels of L-lactate and lower base excess (BE) and HCO(3)(-) values for cattle fed pelleted grain reflect a greater risk of grain-acid overload.

Acid-Base Equilibrium↗
PubMed2005

Plasma malonaldehyde (MDA) and total antioxidant status (TAS) during lactation in dairy cows.

Metabolic profiles are widely used to monitor health, reproductive status and nutritional status. In the last few years, the evaluation of oxidative stress has contributed increasingly to our knowledge of the fundamental mechanisms involved in metabolic disorders, especially important in dairy cows, in which lactation imposes great physiological demands on the body's homeostatic mechanisms. The aim of the present study was to evaluate oxidative status in healthy cows during lactation (from lactation onset to peak lactation) using two parameters: (i) plasma levels of malondialdehyde (MDA) and (ii) total antioxidant status (TAS). Our results confirm that nutrition can influence the characteristic metabolic changes occurring between lactation onset and peak lactation. In addition, the combination of MDA and TAS can provide complementary information about the metabolic status of the cow. Thus, the proper metabolic adaptation to the onset of lactation, showed by metabolic profiles, contrasts with the high levels of free radicals which cause lipid peroxidation and high MDA values (68.99+/-33.64 microm/L) which is maintained only for a short period of time. In this moment, the antioxidant system can cope efficiently with lipoperoxide production. The most remarkable fact was the great inter-individual variations observed in MDA that might be studied in further investigations. When the animal reaches peak lactation, metabolic status is stabilized, and this is reflected by antioxidant status with mean values of 28.87+/-5.33 microm/L for MDA and 0.154+/-0.002 mmol/L for TAS values.

Animals↗
PubMed2005

Oxidative status during late pregnancy and early lactation in dairy cows.

In the last few years, the detection of free radical damage and the body's defences against it have become increasingly important in clinical medicine as a complementary tool in the evaluation of metabolic status. The aim of this study was to evaluate, under field conditions, the anti-oxidant status of healthy cows during late pregnancy and lactation onset using two parameters: (1) plasma levels of malondialdehyde (MDA), a degradation product of lipid peroxidation, and (2) total antioxidant status (TAS). Results were compared with those obtained in another group of cows with lesser metabolic demands. We also investigated possible relationships between antioxidant status markers and other relevant blood parameters. Our results confirmed the characteristic metabolic changes associated with late pregnancy and early lactation. MDA and TAS provided an accurate reflection of the internal physiological status of the animal. The data indicated increased lipid peroxidation around parturition, but with wide individual variations that may be attributable not only to the physiological stage but also to unknown factors that will have to be further considered in future studies.

Animals↗
PubMed2000

A gene associated with filamentous growth in Ophiostoma novo-ulmi has RNA-binding motifs and is similar to a yeast gene involved in mRNA splicing.

The COL1 gene was isolated from Ophiostoma novo-ulmi using the techniques of insertional mutagenesis and plasmid rescue. Sequence analyses suggest that the COL1 gene encodes a unique protein of 826 amino acids with consensus-type RNA-binding domains, most similar to a putative protein from Schizosaccharomyces pombe which resembles the C-terminus of the Saccharomyces cerevisiae U4/U6 splicing factor PRP24. Disruption of the COL1 gene produced the yeast-like col1 mutant. The inability of the mutant to synthesize the COL1 gene product was confirmed by transcript analysis. Transformation of the col1 mutant with the COL1 gene restored the wild phenotype and production of the 4.0-kb mRNA. The results from this study demonstrate that the COL1 RNA-binding protein is associated with filamentous growth in O. novo-ulmi.

Amino Acid Sequence↗
PubMed1996

Evaluation of some biomonitoring markers in occupationally exposed populations to acrylonitrile.

In the present work we studied acrylonitrile (AN) occupationally exposed populations and respective control individuals working in a Portuguese plant producing acrylic textile fibers. Three subgroups of individuals were considered: controls (C), workers of the continuous polymerization (CP) area, and workers of equipment maintenance (MM). Besides aiming to contribute to a better understanding of the hazardous exposure of man to AN, the study aimed to help validate and optimize the use of a combination of methods applied to human populations exposed to genotoxic compounds. Three main compartments related to the dose or effect of the hazardous compound were evaluated using various assessment methods: 1) internal dose (genotoxicity in urine, indicators of oxidative stress, induction of cytochromes P450); 2) biological effective dose (hemoglobin adducts); and 3) early biological effects (chromosomal aberrations, sister chromatid exchanges). Although concern with exposure to AN has long been the subject of numerous studies, they have been carried out essentially in animals and using in vitro systems. The significant differences (P < 0.01) found in the chromosomal aberrations of MM are in agreement with the highly significant levels of hemoglobin adducts described in another study performed in the same population. Hemoglobin adducts were also sensitive in detecting a hazardous exposure in the case of CP. The results obtained for the lipid peroxidation indicator used seem to confirm the AN capability of inducing lipid peroxidation in vivo. From the results available it seems that chromosomal aberrations as well as hemoglobin adducts are accurate and sensitive biomonitoring markers for AN exposure.

Acrylonitrile↗
PubMed1977

The fate of intratracheal 14C-guanidinated pancreatic elastase in hamster lung.

Native pancreatic elastase and guanidinated elastase have similar in vitro and in vivo properties and produce emphysema of similar severity in hamsters. 14C-guanidinated pancreatic elastase (16,000 cpm/0.2 mg) was instilled into the trachea of anesthetized hamsters. Within 24 hours the radiolabel found in the lungs rapidly decreases to 12% of the original 16,000 cpm and to 1% after 96 hours. Most of the radiolabel and elastase activity found in the lungs can be removed by bronchopulmonary lavage up to 48 hours after installation. Although seemingly very small, there is a significant amount of radiolabel (1-2%) which cannot be removed from the lungs by extensive bronchopulmonary lavage.

Animals↗
PubMedDate not supplied

[Bezoar of stones].

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Bezoars↗