102 resultados para blood response


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

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

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Turtles are among the most endangered vertebrate groups, and the main threats to populations are environmental pollution and habitat degradation. The species Phrynops geoffroanus, popularly known as “Geoffroy’s side-necked turtle”, has proliferated in polluted environments, where adverse conditions could influence their living habits and physiological condition. Studies that monitor the effects of environmental pollution are key to understanding the species’ biology and designing effective conservation strategies. Thus, the analysis of hematological and biochemical parameters has been shown to be important in assessing the health of wild animals and risks for the animal and ecosystem. This study aimed to assess the environmental influence on the physiology of a P. geoffroanus population through the evaluation of antioxidant status and responses to environmental stressors, compared to specimens from a place under controlled conditions. Blood samples of 60 specimens were collected, 30 from the Felicidade Stream, polluted environment, within the city of São José do Rio Preto, and 30 from the “Reginaldo Uvo Leone” breeding farm, Tabapuã, SP, a place under controlled conditions, whose samples constituted the control group. They were evaluated by hemogram and by determining thiobarbituric acid reactive species (TBARS), Trolox-equivalent antioxidant capacity (TEAC) and the activities of the antioxidant enzymes catalase and glucose-6-phosphate dehydrogenase (G6PDH). There was a wide variation in hematological parameters of P. geoffroanus from the urban environment. The red blood cell count and hemoglobin values were significantly less than those observed in animals from the breeding farm (P = 0.0004; P = 0.0371, respectively). There was a significant increase in the number of thrombocytes (P < 0.0001) and leukocytes (P < 0.0001) in the animals from Felicidade Stream. The stress indices were similar between the two groups (P = 0.4077). TBARS levels showed the cytotoxic potential of compounds in the urban environment, whose animals had elevated levels of lipid peroxidation (P < 0.0001), despite showing a response to environmental damages with increase in antioxidant capacity, as demonstrated by the TEAC assay (P = 0.0207). The lower catalase enzyme activity noted in individuals from the urban environment (P = 0.000184) could be due to the presence of inhibitory compounds. On the other hand, G6PDH activity was higher (P = 0.002962), where this enzyme acts in the generation of NADPH, which is used in several detoxification pathways. We conclude that environmental contamination can increase oxidative damages and generate physiological changes in this species. These data are very useful for the conservation of P. geoffroanus and turtles in general, and confirm that these techniques are effective in monitoring natural regions and that P. geoffroanus can serve as an environmental contamination bioindicator.

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The use of an amperometric biosensor for the salicylate determination in blood serum is described. The biosensor is based on salicylate hydroxylase (EC 1.14.13.1) electropolymerized onto a glassy carbon-working electrode with polypyrrole and glutaraldehyde, to improve the biosensor lifetime. The hexacyanoferrate (II) was also incorporated to work as a redox mediator to minimize possible interferences. The salicylate is enzymatically converted to catechol, which is monitored amperometrically by its electrooxidation at +0.170 V versus SCE (saturated calomel electrode). Salicylate determination was carried out maintaining the ratio between β-NADH and salicylate at 4:1 (30°C). The amperometric response of the biosensor was linearly proportional to the salicylate concentration between 2.3 x 10-6 and 1.4 x 10-5 mol l- 1, in 0.1 mol l-1 phosphate buffer (pH 7.8), containing 0.1 mol l-1 KCl and 5.0 x 10-4 mol l-1 Na2H2EDTA, as supporting electrolyte. The recovery studies, in the presence of several interfering compounds, showed recoveries between 96.4 and 104.8%. The useful lifetime of the biosensor in the concentration range evaluated was at least 40 days, in continuous use. Blood serum samples analyzed by this biosensor showed a good correlation compared to the spectrophotometric method (Trinder) used as reference, presenting relative deviations lower than 7.0%. (C) 2000 Elsevier Science B.V.

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In the present experiments, we investigated a possible involvement of noradrenergic receptors of the lateral hypothalamus (LH) in the water intake and pressor response induced by cholinergic stimulation of the medial septal area (MSA) in rats. The cholinergic agonist carbachol (2 nmol) injected into the MSA induced water intake and pressor response. The injection of an α2-adrenergic agonist, clonidine (20 and 40 nmol), but not of an α1-adrenergic agonist, phenylephrine (80 and 160 nmol), into the LH inhibits the water intake induced by carbachol injected into the MSA. The injection of clonidine or phenylephrine into the LH produced no change in the MAP increase induced by carbachol injected into the MSA. The present results suggest that adrenergic pathways involving the LH are important for the water intake, but not for the pressor response, induced by cholinergic activation of the MSA. © 1994.

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

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Background: Studies have investigated the influence of neuromuscular electrostimulation on the exercise/muscle capacity of patients with heart failure (HF), but the hemodynamic overload has never been investigated. The aim of our study was to evaluate the heart rate (HR), systolic and diastolic blood pressures in one session of strength exercises with and without neuromuscular electrostimulation (quadriceps) in HF patients and in healthy subjects. Methods: Ten (50% male) HF patients and healthy subjects performed three sets of eight repetitions with and without neuromuscular electrostimulation randomly, with one week between sessions. Throughout, electromyography was performed to guarantee the electrostimulation was effective. The hemodynamic variables were measured at rest, again immediately after the end of each set of exercises, and during the recovery period. Results: Systolic and diastolic blood pressures did not change during each set of exercises among either the HF patients or the controls. Without electrostimulation: among the controls, the HR corresponding to the first (85 ± 13 bpm, p = 0.002), second (84 ± 10 bpm, p < 0.001), third (89 ± 17, p < 0.001) sets and recuperation (83 ± 16 bpm, p = 0.012) were different compared to the resting HR (77 bpm). Moreover, the recuperation was different to the third set (0.018). Among HF patients, the HR corresponding to the first (84 ± 9 bpm, p = 0.041) and third (84 ± 10 bpm, p = 0.036) sets were different compared to the resting HR (80 ± 7 bpm), but this increase of 4 bpm is clinically irrelevant to HF. With electrostimulation: among the controls, the HR corresponding to the third set (84 ± 9 bpm) was different compared to the resting HR (80 ± 7 bmp, p = 0.016). Among HF patients, there were no statistical differences between the sets. The procedure was well tolerated and no subjects reported muscle pain after 24 hours. Conclusions: One session of strength exercises with and without neuromuscular electrostimulation does not promote a hemodynamic overload in HF patients. (Cardiol J 2011; 18, 1: 39-46)

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The concentrations of acute phase proteins are correlated with the severity of the surgical trauma, being elevated when severe tissue injury is produced. The aim of this study was to evaluate the leukogram and the acute phase proteins concentrations in healthy female dogs submitted to minimally invasive ovariohysterectomy, with the use of nylon cable ties (G1), and conventional (laparotomy) ovariohysterectomy, with the use of nylon suture (G2), as methods to ligate the ovarian pedicles and uterine body, respectively. Blood samples from 30 adult healthy female dogs (15 for each group) were obtained before surgery, and at 24 and 48 h and 7 days after surgery. Serum protein fractions were determined by means of sodium dodecyl sulfate polyacrylamide gel electrophoresis. Neutrophilia was observed 24 h after both surgical procedures but did not differ (P ≥ 0.05) between the groups. In G1, the estimated concentration of ceruloplasmin increased (P ≤ 0.05) 48 h after the surgical procedure. The estimated ceruloplasmin concentration was significantly higher in G1 (P ≤ 0.05) when compared to G2 48 h postoperatively, and the estimated haptoglobin concentration was also significantly greater in G1 (P ≤ 0.05) than in G2 from 24 h to 7 days after surgery. Through the ceruloplasmin and haptoglobin estimated concentrations, we conclude that the minimally invasive ovariohysterectomy caused a more intense inflammatory response, which was not reflected in the white blood cell count.

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Vitamin A (vitA) is an essential nutrient that acts as an endocrine regulator of several metabolic pathways, modulating normal growth and health status of animals. Although the importance of vitA for normal haematology and immune response is well documented for higher vertebrates, there is limited information on the physiological effects of vitA on fish. Therefore, we designed a 130-day feeding trial to evaluate the effect of vitA supplementation on growth, haematology, immune function and resistance to experimental infection with Aeromonas hydrophila and cold-induced stress. A group of 320 Nile tilapia fingerlings 7.49 ± 0.19 g weight (mean ± SD) were randomly stocked into 40 250 L-aquaria and fed practical diets containing graded levels of vitA (0, 0.06, 0.12, 0.24, 0.48, 0.96, 1.92, 3.84 mg retinol (ROH) kg−1 diet. Growth, haematology, plasma protein profile and immune response were significantly affected by vitA supplementation; however, no clear protective effect of vitA supplementation on disease and cold stress resistance were observed in this study. Clinical signs of vitA deficiency were: resting and abnormal swimming behaviour, exophthalmia, haemorrhages at the base of fins and on skin, serous fluids in abdominal cavity, neutropenia, reduction in red blood cell count, haematocrit and haemoglobin evolving to high mortality rates in a short period of time. A dietary level of vitA around 1.2 mg ROH kg−1 may be required to prevent gross deficiency signs and promote proper growth and health status of Nile tilapia. VitA does not seem to have a pronounced effect on leucocyte differentiation, but clearly plays an important role on maintaining normal erythropoiesis.

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The objective of this study was to evaluate the effect of one or two doses of the anti-rabies vaccination on the serum concentration of cortisol and the humoral immune response in cattle as well as the correlation between serum cortisol concentrations and the titers of rabies-neutralizing antibodies. Nelore cattle were randomly assigned to one of three groups, which were vaccinated with one dose of rabies vaccine (group GVSR, N = 15), two doses of rabies vaccine (group GVR, N = 15) or were not vaccinated (group Gc, N = 15). A commercial liquid inactivated rabies vaccine was used. The stressors imposed on the cattle were vaccination, corral handling and the presence of people. Blood samples were collected on days 0, 30 and 60 post-vaccination. Serum cortisol concentrations were determined using a solid-phase radioimmunoassay, and rabies antibody titers were determined using a serum neutralization test with BHK21 cells (RFFIT). Both serum cortisol concentrations and antibody titers increased after the second (booster) vaccination (P < 0.05). In all the groups, the serum cortisol concentrations increased after the cattle were handled in the corral (P < 0.05). No correlation was observed between the serum cortisol concentrations and the antibody titers with any treatment or on any observation day. In conclusion, booster vaccination is indispensable for primovaccinated cattle in achieving high and protective levels of rabies antibodies. Although booster vaccination and frequent cattle handling in corrals are stressors, the response is not strong enough to cause immunosuppression in cattle.