962 resultados para Pressure effects


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Sildenafil attenuates acute pulmonary embolism-induced pulmonary hypertension. However, the hemodynamic effects of sildenafil in combination with other vasodilators during acute pulmonary embolism have not been examined yet. In the present study, we examined the hemodynamic effects of combined sildenafil (0.25 mg/kg, i.v.) and L-arginine (100, 200, 500, and 1000 mg/kg/h, i.v.) in an anesthetized dog model of acute pulmonary embolism. Plasma nitrite/nitrate (NOx) and cGMP concentrations were determined using an ozone-based chemiluminescence assay and a commercial enzyme immunoassay, respectively. We found that L-arginine alone did not attenuate acute pulmonary embolism-induced pulmonary hypertension. However, significant decreases in mean pulmonary artery pressure were observed 30, 45, 60, and 75 min after the administration of sildenafil alone or after the combined administration of sildenafil and L-arginine (all P<0.05). No significant differences among groups were observed in the respiratory parameters. While L-arginine significantly increased NOx concentrations, cGMP concentrations increased only when sildenafil was administered (all P<0.05). These results suggest that while sildenafil attenuates acute pulmonary embolism-induced pulmonary hypertension, L-arginine does not enhance the beneficial hemodynamic effects of sildenafil. In addition, these findings suggest that stimulation of NO synthesis with L-arginine during acute pulmonary embolism does not produce beneficial effects. (c) 2005 Elsevier B.V. All rights reserved.

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Maternal undernutrition affects the foetal development, promoting renal alterations and adult hypertension. The present study investigates, in adult male rats, the effect of food restriction in utero on arterial blood pressure changes (AP), and its possible association with the number of nephrons, renal function and angiotensin II (AT1R/AT2R), glucocorticoid (GR) and mineralocorticoid (MCR) receptors expression. The daily food supply to pregnant rats was measured and one group (n=5) received normal quantity of food (NF) while the other group received 50% of that (FR50) (n=5). The AP was measured weekly. At 16 weeks of life, fractionator’s method was used to estimate glomeruli number in histological slices. The renal function was estimate by creatinine and lithium clearances. Blood and urine samples were collected to biochemical determination of creatinine, sodium, potassium and lithium. At 90th and 23rd days of life, kidneys were also processed to AT1R, AT2R, GR and MCR immunolocalization and for western blotting analysis. FR50 offspring shows a significant reduction in BW (FR50: 5.67 ± 0.16 vs. 6.84 ± 0.13g in NF, P<0.001) and increased AP from 6th to 12nd week (6thwk FR50: 149.1 ± 3.4 vs. 125.1 ± 3.2mmHg in NF, P<0.001and, 12ndwk FR50: 164.4 ± 4.9 vs. 144.0 ± 3.3 mmHg in NF, P=0.02). Expression of AT1R and AT2R were significantly decreased in FR50 (AT1, 59080 ± 2709 vs. 77000 ± 3591 in NF, P=0.05; AT2, 27500 ± 95.50 vs. 67870 ± 1509 in NF, P=0.001) while the expression of GR increased in FR50 (36090 ± 781.5 vs. 4446 ± 364.5 in NF, P=0.0007). The expression of MCR did not change significantly. We also verified a pronounced decrease in fractional urinary sodium excretion in FR50 offspring (0.03 ± 0.02 vs. 0.06 ± 0.04 in NF, p=0.03). This occurred despite unchanged creatinine clearance. The study led us to suggest that fetal undernutrition, with increased fetal exposure... (Complete abstract click electronic access below)

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Coordenadoria de Aperfeiçoamento em Pesquisa (CAPES)

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This study evaluated the influence of fluoride mouth rinses and repolishing on the superficial morphology and color stability of nanofilled resin. About 150 specimens were prepared and polished using aluminum oxide discs for 15 s with a pressure of 2 kg. The experimental groups were divided according to the immersion medium (artificial saliva, 0.5% sodium fluoride, Fluordent Reach, Oral B, Fluorgard) and repolishing procedure (without and with). The specimens were continuously immersed for 1 week. Thereafter, half of each sample was repolished. A color reading was performed after 24 h of immersion in the artificial saliva baseline, after continuous immersion, and after repolishing. The superficial morphology was examined using scanning electron microscopy (SEM) in a qualitative way. Color change (∆E) data were submitted to a mixed analysis of variance using a Shapiro-Wilk test (p>0.05 for the different immersion media) and Sidak's test (p<0.05 for the differences between groups). In the interaction between the repolishing and the immersion media, Fluorgard showed a statistical difference between the ∆E values with and without repolishing (p<0.0001). On the SEM observations, both Fluordent Reach and Fluorgard caused degradation of the superficial resinous matrix of the composite after continuous immersion. This matrix was removed after repolishing.

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Adolescence has been proposed as an ontogenic period of vulnerability to stress. Nevertheless, the impact of stressful events during adolescence in cardiovascular activity is poorly understood. Therefore, the purpose of this study was to investigate the immediate and long-lasting effects of exposure to stressful events during adolescence in cardiovascular function of rats. To this end, we compared the impact of 10-days exposure to two chronic stress protocols: the repeated restraint stress (RRS, homotypic) and chronic variable stress (CVS, heterotypic). Independent groups of animals were tested 24 h (immediate) or three weeks (long-lasting) following completion of stress period. Exposure to CVS, but not RRS, during adolescence increased basal HR values without affecting arterial pressure, which was followed by augmented power of oscillatory component at low frequency (sympathetic-related) of the pulse interval (PI). RRS enhanced variance of the PI with an increase in the power of both low and high (parasympathetic-related) frequency components. RRS also increased the baroreflex gain. Neither RRS nor CVS affected systolic arterial pressure variability. The RRS-evoked changes in PI variability were long-lasting and persisted into adulthood while all alterations evoked by the CVS were reversed in adulthood. These findings indicate a stress type-specific influence in immediate and long-term effects of stress during adolescence in cardiovascular function. While immediate changes in cardiovascular function were mainly observed following CVS, long-lasting autonomic consequences in adulthood were observed only in animals exposed to RRS during adolescence.

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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BACKGROUND: Hypertension is the most prevalent comorbidity after heart transplantation (HT). Exercise training (ET) is widely recommended as a key non-pharmacologic intervention for the prevention and management of hypertension, but its effects on ambulatory blood pressure (ABP) and some mechanisms involved in the pathophysiology of hypertension have not been studied in this population. The primary purpose of this study was to investigate the effects of ET on ABP and arterial stiffness of HT recipients.METHODS: 40 HT patients, randomized to ET (n = 31) or a control group (n = 9) underwent a maximal graded exercise test, 24-hour ABP monitoring, and carotid-femoral pulse wave velocity (PWV) assessment before the intervention and at a 12-week follow-up assessment. The ET program was performed thrice-weekly and consisted primarily of endurance exercise (40 minutes) at similar to 70% of maximum oxygen uptake (Vo(2MAX))RESULTS: The ET group had reduced 24-hour (4.0 +/- 1.4 mm Hg, p < 0.01) and daytime (4.8 +/- 1.6 mm Hg, p < 0.01) systolic ABP, and 24-hour (7.0 +/- 1.4 mm Hg, p < 0.001) daytime (7.5 +/- 1.6 mm Hg, p < 0.001) and nighttime (5.9 +/- 1.5 mm Hg, p < 0.001) diastolic ABP after the intervention. The ET group also had improved Vo(2MAX) (9.7% +/- 2.6%, p < 0.001) after the intervention. However, PWV did not change after ET. No variable was changed in the control group after the intervention.CONCLUSIONS: The 12-week ET program was effective for reducing ABP but not PWV in heart transplant recipients. This result suggesfs that endurance ET may be a tool to counteract hypertension in this high-risk population. (C) 2015 International Society for Heart and Lung Transplantation. All rights reserved.

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

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