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Fractional Sodium Excretion (fractional + sodium_excretion)
Selected AbstractsIntrauterine growth restriction reduces nephron number and renal excretory function in newborn piglets,ACTA PHYSIOLOGICA, Issue 2 2002R. Bauer ABSTRACT To examine the effects of intrauterine growth restriction on nephron number, renal circulation, and renal excretory functions in newborns, studies were conducted on 1-day-old anaesthetized piglets, divided into normal weight (n = 6) and intrauterine growth restricted (n = 6) piglets. Renal blood flow was measured by coloured microspheres, glomerular filtration rate was measured by inulin clearance, and osmotic clearance and fractional sodium excretion were calculated. In addition, an estimation of the nephron number was performed by counting representative glomerular numbers in microscopic sections. Newborn intrauterine growth restricted piglets exhibited a reduced glomerular filtration rate and osmotic clearance (P < 0.05), whereas renal blood flow and the filtration fraction as well as fractional sodium excretion were similar in normal weight and intrauterine growth restricted piglets. The nephron number was markedly reduced in intrauterine growth restricted piglets even if the nephron number was related to body weight (P < 0.01). There was a positive correlation between nephron number and glomerular filtration rate (r = 0.69, P < 0.05). Reduced glomerular filtration rate of newborn intrauterine growth restricted piglets is associated with a reduced nephron number. Thus, at birth, compensatory response of renal function due to nephron deficit does not exist in intrauterine growth restricted piglets. [source] Long-term evolution of the acute tubular necrosis (ATN) induced by glycerol: role of myofibroblasts and macrophagesINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 4 2002Telma J. Soares Summary. Late structural changes such as interstitial fibrosis in the renal cortex and tubular atrophy have been detected after severe acute tubular necrosis (ATN). The aim of this study was to investigate the expression of fibronectin, ,-smooth muscle actin and macrophages during the evolution of the ATN induced by glycerol and their relationship with the late structural changes observed in the kidneys of these animals. Forty-nine male Wistar rats were injected with a 50% glycerol solution, 8 mL/kg (4 mL/kg applied i.m. to each hind leg) and 14 with 0.15 m NaCl solution. Before glycerol injection on day 1, water was removed for 17 h. Blood and urine samples were collected 1 day after the injection to quantify sodium and creatinine. The animals were killed 5, 30 and 60 days after the injections and the kidneys removed for histological and immunohistochemical studies. The results of the histological and immunohistochemical studies were scored according to the extent of lesion or staining in the cortical tubulointerstitium, respectively. The percentage of tubulointerstitial lesions was determined by morphometry. Glycerol-injected rats presented a transitory increase in plasma creatinine levels and in fractional sodium excretion. The immunohistochemical studies showed increased fibronectin, ,-smooth muscle actin (,-SM-actin), TGF-, and ED-1 (macrophages) staining in the renal cortex from rats killed 5, 30 and 60 days after glycerol injection (P < 0.05) compared to control. The animals killed on day 30 and 60 also presented chronic lesions (fibrosis, tubular dilatation and atrophy) in the renal cortex, despite the recovery of renal function. Macrophages, TGF-, and myofibroblasts may have contributed to the development of renal fibrosis in these rats. [source] Different protective actions of losartan and tempol on the renal inflammatory response to acute sodium overloadJOURNAL OF CELLULAR PHYSIOLOGY, Issue 1 2010María I. Rosón The aim of this work was to study the role of local intrarenal angiotensin II (Ang II) and the oxidative stress in the up-regulation of pro-inflammatory cytokines expression observed in rats submitted to an acute sodium overload. Sprague,Dawley rats were infused for 2,h with isotonic saline solution (Control group) and with hypertonic saline solution alone (Na group), plus the AT1 receptor antagonist losartan (10,mg,kg,1 in bolus) (Na,Los group), or plus the superoxide dismutase mimetic tempol (0.5,mg,min,1,kg,1) (Na,Temp group). Mean arterial pressure, glomerular filtration rate, and fractional sodium excretion (FENa) were measured. Ang II, NF-,B, hypoxia inducible factor-1, (HIF-1,), transforming growth factor ,1 (TGF-,1), smooth muscle actin (,-SMA), endothelial nitric oxide synthase (eNOS), and RANTES renal expression was evaluated by immunohistochemistry. Ang II, NF-,B, and TGF-,1 and RANTES early inflammatory markers were overexpressed in Na group, accompanied by enhanced HIF-1, immunostaining, lower eNOS expression, and unmodified ,-SMA. Losartan and tempol increased FENa in sodium overload group. Although losartan reduced Ang II and NF-,B staining and increased eNOS expression, it did not restore HIF-1, expression and did not prevent inflammation. Conversely, tempol increased eNOS and natriuresis, restored HIF-1, expression, and prevented inflammation. Early inflammatory markers observed in rats with acute sodium overload is associated with the imbalance between HIF-1, and eNOS expression. While both losartan and tempol increased natriuresis and eNOS expression, only tempol was effective in restoring HIF-1, expression and down-regulating TGF-,1 and RANTES expression. The protective role of tempol, but not of losartan, in the inflammatory response may be associated with its greater antioxidant effects. J. Cell. Physiol. 224:41,48, 2010 © 2010 Wiley-Liss, Inc. [source] Biological Activity of Endogenous Atrial Natriuretic Peptide During Cardiopulmonary BypassARTIFICIAL ORGANS, Issue 10 2000Nobuhiko Hayashida Abstract: To evaluate the effect of cardiopulmonary bypass (CPB) on atrial natriuretic peptide (ANP) biological activity in patients undergoing cardiac operations, we conducted a prospective study. Ten patients undergoing mitral valve surgery were enrolled. Plasma levels of ANP and cyclic guanosine monophosphate (cGMP), hemodynamic variables, and renal function parameters were assessed perioperatively. The molar ratio of cGMP to ANP (as a marker for ANP biological activity) decreased significantly (p < 0.05) during CPB despite similar plasma ANP levels. The ratio correlated inversely with the duration of CPB (r = ,0.85, p = 0.002). The ratio also correlated with fractional sodium excretion (r = 0.65, p = 0.04) and correlated inversely with pulmonary vascular resistance (r = ,0.79, p = 0.009) and atrial filling pressure (r = ,0.84, p = 0.003) postoperatively. CPB decreased the molar ratio of cGMP to ANP, which may represent ANP biological activity, such as vasodilation and natriuresis. The phenomenon may contribute to water,sodium retention and pulmonary hypertension after cardiac surgery. [source] | |||||||||||||