51 research outputs found
Renin-angiotensin system unresponsiveness in pheochromocytoma
No full textRenin-angiotensin system unresponsiveness in phaeochromocytoma.
Coruzzi P, Musiari L, Biggi A, Mossini GL, Novarini A.
SourceInstitute of Semeiotica Medica, University of Parma, Italy.
Abstract
Water immersion to the neck is able to provoke a profound suppression of the renin-angiotensin system in several clinical conditions associated with hyper-reninaemia. Both hyper-reninaemia and secondary aldosteronism have sometimes been described in phaeochromocytoma. We report on two patients, with surgically proven phaeochromocytoma, in whom water immersion, performed before surgery, failed to induce any significant change in plasma renin activity
Renin aldosterone system suppression during water immersion in renovascular hypertension
No full textRenin-aldosterone system suppression during water immersion in renovascular hypertension.
Coruzzi P, Biggi A, Musiari L, Ravanetti C, Novarini A.
Abstract
We studied renin-aldosterone system behaviour in five renovascular hypertensive patients during central hypervolaemia by water immersion to the neck. Water immersion significantly suppressed the high peripheral renin levels of the patients despite an autonomic renin secretion from the stenotic kidney, a significant reduction of mean blood pressure and an increase in distal tubule sodium concentration. The effect of immersion on plasma aldosterone appeared to be primarily mediated via suppression of plasma renin activity (PRA). Our data suggest that: (a) the renin secretion is mainly modulated by cardiopulmonary receptors activity; (b) the neurogenic reflex control of plasma renin activity is very effective in renovascular hypertension
Low-pressure receptor activity and exaggerated natriuresis in essential hypertension
No full textLow-pressure receptor activity and exaggerated natriuresis in essential hypertension.
Coruzzi P, Novarini A, Biggi A, Lazzeroni E, Musiari L, Ravanetti C, Tagliavini S, Borghetti A.
Abstract
Urinary sodium excretion, central hemodynamics, and mean arterial pressure (MAP) were studied in 7 normal subjects and 19 hypertensive patients during both central hypervolemia by water immersion to the neck (NI) and extracellular volume expansion by i.v. saline infusion. During 2-hour NI, 12 out of the 19 hypertensives exhibited a significant fall in MAP (p less than 0.001). Exaggerated natriuresis did not occur in these patients (ns). In the remaining 7 hypertensive patients in whom, during NI, MAP was unchanged, exaggerated natriuresis was found (p less than 0.001). During saline infusion, MAP was either unchanged or increased and exaggerated natriuresis was found in all hypertensive patients (p less than 0.001) previously submitted to NI. Our findings suggest that a high MAP is a major determinant of exaggerated natriuresis in arterial hypertension
Dopamine blockade and natriuresis during water immersion in normal man
No full textDopamine blockade and natriuresis during water immersion in normal man.
Coruzzi P, Biggi A, Musiari L, Ravanetti C, Vescovi PP, Novarini A.
Abstract
Natriuresis was studied during water immersion in eight normal subjects either in the absence or in the presence of dopamine blockade by domperidone. Creatinine clearance showed no significant changes; urine flow remained significantly above control values during water immersion, implying persistent suppression of antidiuretic hormone. The marked natriuresis seen during water immersion alone was significantly blunted (P less than 0.05) but not abolished during water immersion plus domperidone. Suppression of the renin-aldosterone system by water immersion alone was not significantly different from that obtained during water immersion plus dopamine blockade. On the contrary, plasma prolactin levels, previously suppressed during water immersion alone, were significantly stimulated during water immersion plus domperidone, thus indirectly suggesting a role of dopamine in mediating the blunted natriuresis seen during water immersion
Circulating opioid peptides during water immersion in normal man
No full textCirculating opioid peptides during water immersion in normal man.
Coruzzi P, Ravanetti C, Musiari L, Biggi A, Vescovi PP, Novarini A.
SourceIstituto di Semeiotica Medica, University of Parma, Italy.
Abstract
1. This study was designed to evaluate variations in plasma beta-endorphin, methionine-enkephalin, adrenocorticotropic hormone and serum prolactin in healthy volunteers during head-out water immersion. 2. Water immersion induced an increase in methionine-enkephalin plasma levels, which was associated with a significant fall in mean arterial pressure and heart rate. 3. Conversely, a suppression of plasma beta-endorphin, adrenocorticotropic hormone and serum prolactin was detected during water immersion. 4. We suggest that a dopaminergic inhibitory control mechanism may be involved in regulating circulating levels of beta-endorphin, adrenocorticotropic hormone and prolactin in normal subjects undergoing extracellular fluid volume expansion produced by water immersion
A new diagnostic test for primary aldosteronism
No full textA new diagnostic test for primary aldosteronism.
Coruzzi P, Musiari L, Biggi A, Carra N, Panzali AF, Novarini A.
SourceIstituto di Semeiotica Medica, Università di Parma, Italy.
Abstract
Isotonic-isooncotic central volume expansion by head-out water immersion was induced in six aldosterone-producing adenoma subjects and in six patients with idiopathic hyperaldosteronism. Plasma renin activity and plasma aldosterone levels did not significantly change during water immersion while serum cortisol was significantly suppressed (P less than .001) and the aldosterone-cortisol ratio increased (P less than .02) in aldosterone-producing adenoma patients. Water immersion also revealed the failure of plasma aldosterone levels to decrease below 10 ng/dL in these subjects, thus confirming previous results obtained during isotonic saline infusion. Otherwise, plasma renin activity and plasma aldosterone were significantly reduced (P less than .05 and P less than .01 respectively) by water immersion and plasma aldosterone invariably fell below 10 ng/dL in patients with idiopathic aldosteronism. In view of the diagnostic reliability of such a suppression test we conclude that water immersion is suitable for discriminating between the two forms of primary aldosteronism. We therefore suggest its use for assessing renin-aldosterone responsiveness in primary aldosteronism
Calcium and sodium handling during volume expansion in essential hypertension
No full textCalcium and sodium handling during volume expansion in essential hypertension.
Coruzzi P, Biggi A, Musiari L, Ceriati R, Mossini GL, Guerra A, Novarini A.
SourceInstitute of Semeiotica Medica, University of Parma, Italy.
Abstract
To evaluate the actual role of extracellular fluid volume (ECFV) expansion per se in modulating the rate of urinary calcium excretion, a thermoneutral water immersion (WI) study was conducted in 10 normal subjects and 30 patients with essential hypertension. Central hypervolemia by 2 hours of WI caused a significant diuretic and natriuretic response (P < .005) in normal subjects; no significant changes were detected in urinary calcium and magnesium excretion. WI provoked either an appropriate or exaggerated natriuresis (P < .001) in 21 hypertensive patients; these subjects also exhibited a highly positive correlation between urinary sodium and calcium excretion during WI (P < .001). In the remaining nine hypertensive patients, WI produced a significant diuretic response, but a barely discernible (P = NS) natriuresis (inappropriate response). These subjects also exhibited a significant reduction of urinary calcium (P < .001) and magnesium (P < .01) excretion. The data indicate that (1) volume expansion per se may have a role in regulating calcium excretion in hypertensive subjects; (2) a calcium leak may be attributable to a close relationship between urinary sodium and calcium metabolism, and causally related to a disturbance of sodium and volume homeostasis in hypertension
Disparate renal responses to Arginine.HCl in patients with Type 1 Diabetes or Essential Hypertension: role of tubuloglomerular feedback
No full textAbstract
Ten control (C), 10 essential hypertensive (HT) and 9 type 1 diabetic (OM) subjects underwent renal hemodynamic studies of 3-hours infusion of 0.012 mmol.kg.min-1 L-arginine (ARG) buffered with equimolecular HCl.
Mean Arterial Pressure, identical at baseline (8) in C and OM and -, 35% higher in HT (0.001), declined at the 3rd hour by 3.2% (0.001) in HT only. Glomerular Filtration Rate (GFR), identical at B in C and HT and 34% higher in DM (O.001), did not change in C and declined by 5.7 and 4.6% (0.001) in OM and HT. Renal blood flow, higher at B by 11% (0.02)
in DM and lower by 9% (ns) in HT, rose by 23% in C (0.001) and to a significantly lesser extent (0.001 vs C) in both HT (+13%) and OM (+J 1%). Sodium excretion, identical in C, HT and OM at B, rose equally in C and HT (+95% and +103%, respectively) and much more in OM (+213%, 0.'001 vs both C and HT). Absolute Proximal Reabsorption (APR, GFR-clearance of exogenous lithium). slightly elevated at B in HT (13%, 0.05 vs C) and: much higher in DM (44%, 0.001), fell equally in C and HT (-15 and -19%, respectively) and much more in DM (-25%, '0.001 vs both C and HT). Renal hemodynamic response to. ARG.HCl is blunled similarly in HT and DM, with less vasodilation and decreased GFR, but tubular response is similar to C in HT and much more pronounced in DM. During ARG.HCI renal hemodynamic changes have been shown to be largely, modulated by an activation of tubuloglomerular feedbac (TGF) depending, on the natriuretic _ properties of buffering anion HCI (Biggi A et at, J Hypertens, 2007).
Thus, the blunted vasodilatation in HT indicates an altered renal hemo-dynamic response to a normally activated TGF, while in DM, who show high GFR and APR with a deactivated TGF at S, an increased inhibition in tubular reabsorption during ARG.HCI. leading to both an exaggerated distal solute delivery and an abnormally activated TGF, seems to be responsible of the blunted renal vasodilation
EXPERIMENTAL VALIDATION OF MINIATURIZED SPECIMEN DEVELOPED TO PERFORM UNIAXIAL TENSILE TEST ON HIGH-PERFORMANCE MATERIALS
No full textAssociation between salt sensitivity and insulin concentrations in patients with hypertension
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