Blood Volume Expansion
Mostrando 25-36 de 66 artigos, teses e dissertações.
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25. Studies on the mechanism of natriuresis accompanying increased renal blood flow and its role in the renal response to extracellular volume expansion.
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26. Splenic control of intravascular volume in the rat.
1. We tested the hypothesis that hypervolaemia causes an increase in intrasplenic filtration of cell-free fluid out of the vasculature. To this end we developed a preparation in the anaesthetized rat whereby the splenic vein could be non-occlusively cannulated. 2. Haematocrit and plasma protein concentrations were measured in the splenic afferent and efferen
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27. The heart communicates with the kidney exclusively through the guanylyl cyclase-A receptor: acute handling of sodium and water in response to volume expansion.
Disruption of guanylyl cyclase-A (GC-A) results in mice displaying an elevated blood pressure, which is not altered by high or low dietary salt. However, atrial natriuretic peptide (ANP), a proposed ligand for GC-A, has been suggested as critical for the maintenance of normal blood pressure during high salt intake. In this report, we show that infusion of AN
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28. Discharge properties of cardiac and renal sympathetic nerves and their impaired responses to changes in blood volume in heart failure
Sympathetic nerve activity (SNA) consists of discharges that vary in amplitude and frequency, reflecting the level of recruitment of nerve fibers and the rhythmic generation and entrainment of activity by the central nervous system. It is unknown whether selective changes in these amplitude and frequency components account for organ-specific changes in SNA i
American Physiological Society.
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29. Augmentation of the natriuretic activity of exogenous and endogenous atriopeptin in rats by inhibition of guanosine 3',5'-cyclic monophosphate degradation.
To investigate the relationship between AP, cyclic GMP, and sodium excretion, we studied the effect of a cyclic GMP phosphodiesterase inhibitor (M + B22948) on the natriuretic response to (a) an infusion of AP (103-126) and (b) acute volume expansion in rats. The phosphodiesterase inhibitor markedly potentiated the effect of low-dose AP infusions on urinary
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30. Failure to demonstrate a humoral mechanism in the antinatriuresis of acute caval constriction
Previous studies reported from this laboratory provided support for the hypothesis that the natriuresis of volume expansion is mediated in part by a humoral mechanism. In the present study we examined whether suppression of this factor participates in the antinatriuresis of acute constriction of the thoracic inferior vena cava. An isolated kidney was perfuse
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31. The influence of spleen size on the distribution of red cells and plasma
The red cell mass, splenic red cell pool, and plasma volume have been measured in a series of 64 patients with splenomegaly due to haematological disorders. In 45 patients the total blood volume was increased, this being due to expansion of the plasma volume which was closely correlated with spleen size. There was no significant relationship between the red
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32. The renin-angiotensin-aldosterone system in congestive failure in conscious dogs.
The role of the renin-angiotensin-aldosterone system in the development of congestive failure has been assessed in the conscious dog by use of the nonapeptide converting enzyme inhibitor. Constriction of the pulmonary artery or thoracic inferior vena cava was maintained for 2 wk while daily measurements were made of plasma renin activity, plasma aldosterone,
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33. A Humoral Component of the Natriuretic Mechanism in Sustained Blood Volume Expansion
A natriuretic and diuretic response to whole blood infusion in the rat, exaggerated and sustained by intravenous reinfusion of excreted urine, was shown to be associated with increased glomerular filtration and reduced tubular reabsorption. Cross-circulation of animals so responding (donor rats) with isovolemic recipients led to a modest natriuretic and diur
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34. Oxytocin mediates atrial natriuretic peptide release and natriuresis after volume expansion in the rat.
Our previous studies have shown that stimulation of the anterior ventral third ventricular region increases atrial natriuretic peptide (ANP) release, whereas lesions of this structure, the median eminence, or removal of the neural lobe of the pituitary block ANP release induced by blood volume expansion (BVE). These results indicate that participation of the
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35. Role of volume in the regulation of vasopressin secretion during pregnancy in the rat.
We previously observed that osmoregulation and the osmotic threshold for antidiuretic hormone secretion were altered during pregnancy in Sprague-Dawley rats and the present study evaluated the influence of volume on arginine vasopressin (AVP) release during gestation in this species. Basal plasma osmolality (Posm) and intravascular volume were 297 +/- 3 mosm
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36. Effect of Volume Expansion on Hemodynamics of the Hypoperfused Rat Kidney
The hemodynamics of the rat kidney were studied during reduction of renal arterial pressure to 35-40 mm Hg (H), and after volume expansion at that pressure with 0.9% NaCl (IS), 1.7% NaCl (HS), 5% mannitol in 0.9% NaCl (MS), 5% mannitol in water (MW), or 50 mM mannitol + 125 mM NaCl. During H, left renal blood flow (RBF) was 0.8±0.1 ml/min. Expansion with IS