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To the Editor: In the review “Effect of Allopurinol on Blood Pressure: A Systematic Review and Meta-Analysis,” the authors conclude that allopurinol and other xanthine oxidase inhibitors may be used as adjunctive antihypertensive agent. This meta-analysis was performed that included heterogeneous studies as well as trials with poor methodological quality, eg, Siu and colleagues (2006) (an open, nonplacebo-controlled trial including individuals with and without hypertension in which allopurinol decreased only systolic blood BP); Kanbay and colleagues (2007) (open, nonrandomized, nonplacebo-controlled study enrolling normotensive and hypertensive individuals); and Kanbay and colleagues (2011) (an open, nonplacebo-controlled trial including adults with normal blood pressure. Positive results of allopurinol were seen in decreasing systolic but not diastolic BP). Inclusion of these studies may have strengthened the BP-lowering effect of allopurinol. Furthermore, one can reasonably assume that several studies enrolling normotensive individuals are inadequate to support the conclusion that allopurinol may be used to treat hypertension. In the systematic review “Pharmacotherapy for Hyperuricemia in Hypertensive Patients” (Cochrane Database of Systematic Reviews), which has more rigorous entry criteria, the authors found that, to date, there is only one study designed to answer whether allopurinol treatment has a positive effect in reducing BP in hypertensive individuals. Feig and colleagues conducted a double-blind, placebo-controlled, crossover trial that randomized 30 adolescents (11–17 years), newly diagnosed with stage I primary hypertension and with serum uric acid >6 mg/dL, to receive allopurinol 200 mg twice daily for 4 weeks and placebo for 4 weeks with a 2-week washout period between treatments. Although it was a well-conducted study, it had a few limitations, as follows: small sample size; exclusion of more severe hypertensive individuals; short duration of treatment, not sufficient to detect adverse events associated with allopurinol or to evaluate whether the effect on BP is sustained after long-term therapy; and the reserved external validity, extending only to adolescents with mild new diagnosis of hypertension. Another concern is how clinicians might interpret the conclusion of this review. Treatment with allopurinol is not free of risks and interactions. Although rare, serious side effects can be associated with allopurinol therapy, such as fatal Stevens-Johnson syndrome and chronic interstitial nephritis. Therefore, increased incidence of side effects can be observed with the increased prescription of allopurinol. Thus, in light of current evidence, recommendation (or encouraging use) of allopurinol or other hypouricemic agent as initial or adjuvant treatment of hypertension is premature and more “RCTs” are needed.

Leptospirosis is an acute septicemic illness that affects humans in all parts of the world. Approximately 10% of patients with leptospirosis develop severe disease, the Weil syndrome, with jaundice, acute kidney injury (AKI), and pulmonary hemorrhage. Leptospirosis-induced AKI is typically nonoliguric with a high frequency of hypokalemia. Experimental and clinical studies demonstrated that tubular function alterations precede a drop in the glomerular filtration rate and are mainly in the proximal tubule. Studies in humans and animals have demonstrated a decrease in the expression of proximal sodium (NHE3) and water tubular transporter, aquaporin 1 (AQP1) together with higher renal expression of the Na-K-2Cl cotransporter NKCC2. In an experimental model, at the initial phase of the disease, the expression of AQP2, the water transport of the collecting duct, is decreased, which explains the higher incidence of nonoliguric AKI. During the recovery phase of AKI, AQP2 expression increased in human and animals as a compensatory mechanism. Alveolar hemorrhage, pulmonary edema, acute respiratory distress syndrome, or a combination of these features may accompany AKI and is associated with high mortality. Studies with hamsters demonstrated that in leptospirosis a noncardiogenic pulmonary edema occurs consequently to a decrease in the clearance of alveolar fluid, due to a decrease in sodium transporter in the luminal membrane (ENaC) and an increase in the NKCC1 basolateral membrane transporter. Antibiotic treatment is efficient in the early and late/severe phases and revert all kidney transporters. Early and daily hemodialysis, low daily net fluid intake, and lung-protective strategies are recommended for critically ill patients with leptospirosis.

Hypokalemia in leptospirosis acute renal failure (ARF) was studied in nine patients with severe leptospirosis ARF and five patients with moderate leptospirosis ARF and compared with five patients with severe acute tubular necrosis (ATN) and eight healthy individuals. Urinary volumes of both the severe and moderate leptospirosis groups were higher than those of the severe ATN group. Leptospirosis groups had serum potassium levels lower than those found in the healthy and severe ATN groups. Serum sodium levels were lower in the severe leptospirosis group than in the moderate leptospirosis, the severe ATN, and the healthy groups. There was a positive correlation between the fractional excretion of sodium and potassium in the severe leptospirosis group as well as between serum creatinine and potassium levels in the pooled leptospirosis groups. Urinary pH in the severe and moderate leptospirosis groups was lower than in the severe ATN group. Aldosterone levels were higher in the severe leptospirosis group than in the healthy individuals. Cortisol levels were higher in the leptospirosis groups than in the healthy subjects. These results strongly suggest that hypokalemia in leptospirosis ARF is due to renal potassium wasting potentialized by aldosterone and cortisol, requiring that special attention is given to potassium replacement as well as to volume repletion in the treatment of leptospirosis ARF.

Nephropathic cystinosis is an autosomal recessive systemic severe disease characterized by intralysosomal cystine storage. Cysteamine is an essential component of treatment. There is solid evidence that cystine accumulation itself is not responsible for all abnormalities in cystinosis; there is also a deficiency of glutathione in the cytosol. Patients with cystinosis can be more susceptible to oxidative stress. The patient cohort comprised 23 cystinosis patients (16 males) aged

Background/Aims: Kidney abnormalities are one of the main chronic complications of sickle cell disease (SCD). The aim of this study is to investigate the occurrence of renal tubular abnormalities among patients with SCD. Methods: This is a prospective study with 26 SCD adult patients in Brazil. Urinary acidification and concentration tests were performed using calcium chloride (CaCl2), after a 12h period of water and food deprivation. Fractional excretion of sodium (FENa), transtubular potassium gradient (TTKG) and solute free water reabsorption (TcH2O) were calculated. The SCD group was compared to a group of 15 healthy volunteers (control group). Results: Patient`s average age and gender were similar to controls. Urinary acidification deficit was found in 10 SCD patients (38.4%), who presented urinary pH >5.3 after CaCl2 test. Urinary osmolality was significantly lower in SCD patients (355±60 vs. 818±202mOsm/kg, p=0.0001, after 12h period water deprivation). Urinary concentration deficit was found in all SCD patients (100%). FENa was higher among SCD patients (0.75±0.3 vs. 0.55±0.2%, p=0.02). The TTKG was higher in SCD patients (5.5±2.5 vs. 3.0±1.5, p=0.001), and TcH2O was lower (0.22±0.3 vs. 1.1±0.3L/day, p=0.0001). Conclusions: SCD is associated with important kidney dysfunction. The main abnormalities found were urinary concentrating and incomplete distal acidification defect. There was also an increase in the potassium transport and decrease in water reabsorption, evidencing the occurrence of distal tubular dysfunction.

Background: Leptospirosis is a re-emerging zoonosis with protean clinical manifestations. Recently, the importance of pulmonary hemorrhage as a lethal complication of this disease has been recognized. In the present study, five human necropsies of leptospirosis (Weil‘s syndrome) with extensive pulmonary manifestations were analysed, and the antibodies expressed in blood vessels and cells involved in ion and water transport were used, seeking to better understand the pathophysiology of the lung injury associated with this disease. Principal Findings: Prominent vascular damage was present in the lung microcirculation, with decreased CD34 and preserved aquaporin 1 expression. At the periphery and even inside the extensive areas of edema and intraalveolar hemorrhage, enlarged, apparently hypertrophic type I pneumocytes (PI) were detected and interpreted as a non-specific attempt of clearence of the intraalveolar fluid, in which ionic transport, particularly of sodium, plays a predominant role, as suggested by the apparently increased ENaC and aquaporin 5 expression. Connexin 43 was present in most pneumocytes, and in the cytoplasm of the more preserved endothelial cells. The number of type II pneumocytes (PII) was slightly decreased when compared to normal lungs and those of patients with septicemia from other causes, a fact that may contribute to the progressively low PI count, resulting in deficient restoration after damage to the alveolar epithelial integrity and, consequently, a poor outcome of the pulmonary edema and hemorrhage. Conclusions: Pathogenesis of lung injury in human leptospirosis was discussed, and the possibility of primary noninflammatory vascular damage was considered, so far of undefinite etiopathogenesis, as the initial pathological manifestation of the disease.

Toxocariasis is usually manifested as visceral larva migrans. Nervous system involvement is a rare complication. In this report, we describe one case of meningoencephalitis due to Toxocara canis and review the literature. We report a previously healthy two-year-old boy who was admitted after 24 hours of severe neurologic symptoms with marked eosinophilic pleocytosis in the cerebrospinal fluid and a single subcortical lesion detected by cerebral magnetic resonance imaging. Both serum and spinal fluid tested positive for T. canis. Initial treatment with thiabendazole was ineffective. After marked improvement in clinical and laboratory results were achieved using albendazole and corticosteroids, the child was discharged.

Background Renal evaluation studies are rare in American Cutaneous Leishmaniasis (ACL). The aim of this study is to investigate whether specific treatment reverts ACL-associated renal dysfunction. Methods A prospective study was conducted with 37 patients with ACL. Urinary concentrating and acidification ability was assessed before and after treatment with pentavalent antimonial. Results The patients mean age was 35.6 ± 12 years and 19 were male. Before treatment, urinary concentrating defect (U/Posm Conclusion As previously described, urinary concentrating and acidification defects were found in an important number of patients with ACL. Present results demonstrate that only some patients recover urinary acidification capacity, while no one returned to normal urinary concentration capacity.

Although leptospirosis may be fatal in childhood, the experience of many clinicians working in disease-endemic areas is that classic Weil's disease and death are less common among pediatric patients. The aim of the study was to ascertain disease spectrum and outcome differences in severe pediatric and adult leptospirosis in a large at-risk population. Epidemiologic, clinical, and laboratory data were obtained on hospitalized cases from Sao Paulo during 2004–2006. A total of 42 case-patients < 18 years of age and 328 case-patients ≥ 18 years of age were tested during the study. Compared with children, adults had higher rates of jaundice (P = 0.01), elevated serum bilirubin levels (P < 0.01), oliguria (P = 0.02), and elevated creatinine levels (P = 0.01) but not for thrombocytopenia or pulmonary involvement. The overall case-fatality rate was 27% (adult) versus 5% (pediatric) (P < 0.01). Severe pediatric leptospirosis may be less likely to show all classic features of Weil's disease and may be less fatal than in adults.

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Laboratorios de Investigacao Medica (LIMs, Medical Investigation Laboratories) of the Faculdade de Medicina da Universidade de São Paulo (FMUSP, University of São Paulo School of Medicine) Hospital das Clinicas Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Background: Despite advances in supportive care, sepsis-related mortality remains high, especially in patients with acute kidney injury (AKI). Erythropoietin can protect organs against ischemia and sepsis. This effect has been linked to activation of intracellular survival pathways, although the mechanism remains unclear. Continuous erythropoietin receptor activator (CERA) is an erythropoietin with a unique pharmacologic profile and long half-life. We hypothesized that pretreatment with CERA would be renoprotective in the cecal ligation and puncture (CLP) model of sepsis-induced AKI.Methods: Rats were randomized into three groups: control; CLP; and CLP+CERA (5 mu g/kg body weight, i.p. administered 24 h before CLP). At 24 hours after CLP, we measured creatinine clearance, biochemical variables, and hemodynamic parameters. in kidney tissue, we performed immunoblotting-to quantify expression of the Na-K-2Cl cotransporter (NKCC2), aquaporin 2 (AQP2), Toll-like receptor 4 (TLR4), erythropoietin receptor (EpoR), and nuclear factor kappa B (NF-kappa B)-and immunohistochemical staining for CD68 (macrophage infiltration). Plasma interleukin (IL)-2, IL-1 beta, IL-6, IL-10, interferon gamma, and tumor necrosis factor alpha were measured by multiplex detection.Results: Pretreatment with CERA preserved creatinine clearance and tubular function, as well as the expression of NKCC2 and AQP2. in addition, CERA maintained plasma lactate at normal levels, as well as preserving plasma levels of transaminases and lactate dehydrogenase. Renal expression of TLR4 and NF-kappa B was lower in CLP+CERA rats than in CLP rats (p

The aim of this study was to evaluate the effect of Gd-chelate on renal function, iron parameters and oxidative stress in rats with CRF and a possible protective effect of the antioxidant N-Acetylcysteine (NAC). Male Wistar rats were submitted to 5/6 nephrectomy (Nx) to induced CRF. An ionic - cyclic Gd (Gadoterate Meglumine) was administrated (1.5 mM/KgBW, intravenously) 21 days after Nx. Clearance studies were performed in 4 groups of anesthetized animals 48 hours following Gd- chelate administration: 1− Nx (n = 7); 2− Nx+NAC (n = 6); 3− Nx+Gd (n = 7); 4−Nx+NAC+Gd (4.8 g/L in drinking water), initiated 2 days before Gd-chelate administration and maintained during 4 days (n = 6). This group was compared with a control. We measured glomerular filtration rate, GFR (inulin clearance, ml/min/kg BW), proteinuria (mg/24 hs), serum iron (µg/dL); serum ferritin (ng/mL); transferrin saturation (%), TIBC (µg/dL) and TBARS (nmles/ml). Normal rats treated with the same dose of Gd-chelate presented similar GFR and proteinuria when compared with normal controls, indicating that at this dose Gd-chelate is not nephrotoxic to normal rats. Gd-chelate administration to Nx-rats results in a decrease of GFR and increased proteinuria associated with a decrease in TIBC, elevation of ferritin serum levels, transferrin oversaturation and plasmatic TBARS compared with Nx-rats. The prophylactic treatment with NAC reversed the decrease in GFR and the increase in proteinuria and all alterations in iron parameters and TBARS induced by Gd-chelate. NAC administration to Nx rat did not modify the inulin clearance and iron kinetics, indicating that the ameliorating effect of NAC was specific to Gd-chelate. These results suggest that NAC can prevent Gd-chelate nephrotoxicity in patients with chronic renal failure.

This study was designed to measure H-K-ATPase and Na-K-ATPase activities in rat inner medullary collecting duct (IMCD) cells during potassium depletion and loading. Both enzyme activities were similarly distributed from the proximal to the distal portion of this nephron segment. One week K depletion did not stimulate H-K-ATPase activity but reduced Na-K-ATPase activity. Within 2 weeks after the onset of potassium depletion, the rats developed metabolic alkalosis, and H-K-ATPase activity was suppressed while Na-K-ATPase activity had returned to control values. H-K-ATPase activity was suppressed following potassium loading whereas Na-K-ATPase activity was unchanged. The results are consistent with the presence of H-K-ATPase in IMCD and indicate that H-K-ATPase and Na-K-ATPase activities are modulated by potassium intake.

Lithium (Li)-treated patients often develop urinary concentrating defect and polyuria, a condition known as nephrogenic diabetes insipidus (NDI). In a rat model of Li-induced NDI, we studied the effect that sildenafil (Sil), a phosphodiesterase 5 (PDE5) inhibitor, has on renal expression of aquaporin-2 (AQP2), urea transporter UT-A1, Na+/H+exchanger 3 (NHE3), Na+-K+-2Cl−cotransporter (NKCC2), epithelial Na channel (ENaC; α-, β-, and γ-subunits), endothelial nitric oxide synthase (eNOS), and inducible nitric oxide synthase. We also evaluated cGMP levels in medullary collecting duct cells in suspension. For 4 wk, Wistar rats received Li (40 mmol/kg food) or no treatment (control), some receiving, in weeks 2–4, Sil (200 mg/kg food) or Li and Sil (Li+Sil). In Li+Sil rats, urine output and free water clearance were markedly lower, whereas urinary osmolality was higher, than in Li rats. The cGMP levels in the suspensions of medullary collecting duct cells were markedly higher in the Li+Sil and Sil groups than in the control and Li groups. Semiquantitative immunoblotting revealed the following: in Li+Sil rats, AQP2 expression was partially normalized, whereas that of UT-A1, γ-ENaC, and eNOS was completely normalized; and expression of NKCC2 and NHE3 was significantly higher in Li rats than in controls. Inulin clearance was normal in all groups. Mean arterial pressure and plasma arginine vasopressin did not differ among the groups. Sil completely reversed the Li-induced increase in renal vascular resistance. We conclude that, in experimental Li-induced NDI, Sil reduces polyuria, increases urinary osmolality, and decreases free water clearance via upregulation of renal AQP2 and UT-A1.

Objective To assess the effects of atorvastatin (ATORV) on renal function after bilateral ureteral obstruction (BUO), measuring inulin clearance and its effect on renal hemodynamic, filtration, and inflammatory response, as well as the expression of Aquaporin-2 (AQP2) in response to BUO and after the release of BUO. Methods Adult Munich-Wistar male rats were subjected to BUO for 24 hours and monitored during the following 48 hours. Rats were divided into 5 groups: sham operated (n = 6); sham + ATORV (n = 6); BUO (n = 6); BUO + ATORV (10 mg/kg in drinking water started 2 days before BUO [n = 5]; and BUO + ATORV (10 mg/kg in drinking water started on the day of the release of BUO [n = 5]). We measured blood pressure (BP, mm Hg); inulin clearance (glomerular filtration rate [GFR]; mL/min/100 g); and renal blood flow (RBF, mL/min, by transient-time flowmeter). Inflammatory response was evaluated by histologic analysis of the interstitial area. AQP2 expression was evaluated by electrophoresis and immunoblotting. Results Renal function was preserved by ATORV treatment, even if initiated on the day of obstruction release, as expressed by GFR, measured by inulin clearance. Relative interstitial area was decreased in both BUO + ATORV groups. Urine osmolality was improved in the ATORV-treated groups. AQP2 protein expression decreased in BUO animals and was reverted by ATORV treatment. Conclusion ATORV administration significantly prevented and restored impairment in GFR and renal vascular resistance. Furthermore, ATORV also improved urinary concentration by reversing the BUO-induced downregulation of AQP2. These findings have significant clinical implication in treating obstructive nephropathy.

The aim of this study was to evaluate the effects of N-acetylcysteine (NAC) on renal function, as well as on sodium and water transporters, in the kidneys of aged rats. Normal, 8-month-old male Wistar rats were treated (n = 6) or not (n = 6) with NAC (600 mg/L in drinking water) and followed for 16 months. At the end of the follow-up period, we determined inulin clearance, serum thiobarbituric acid reactive substances (TBARS), serum cholesterol, and urinary phosphate excretion. In addition, we performed immunohistochemical staining for p53 and for ED-1-positive cells (macrophages/monocytes), together with Western blotting of kidney tissue for NKCC2, aquaporin 2 (AQP2), urea transporter A1 (UT-A1) and Klotho protein. At baseline, the two groups were similar in terms of creatinine clearance, proteinuria, cholesterol, and TBARS. At the end of the follow-up period, NAC-treated rats presented greater inulin clearance and reduced proteinuria, as well as lower serum cholesterol, serum TBARS, and urinary phosphate excretion, in comparison with untreated rats. In addition, NAC-treated rats showed upregulated expression of NKCC2, AQP2, and UT-A1; elevated Klotho protein expression, low p53 expression, and few ED-1 positive cells. In conclusion, we attribute these beneficial effects of NAC (the significant improvements in inulin clearance and in the expression of NKCC2, AQP2, and UT-A1) to its ability to decrease oxidative stress, inhibit p53 expression, minimize kidney inflammation, and stimulate Klotho expression.

Background Acute kidney injury (AKI) following prolonged laparoscopy is a documented phenomenon. Carbon dioxide pneumoperitoneum induces oxidative stress. Previous experimental studies have shown that the antioxidant, N-acetylcysteine, protects the rat from AKI following ischemia-reperfusion. The aim of this study was to evaluate the effects of N-acetylcysteine (NAC) on rat renal function after prolonged pneumoperitoneum. Methods Normal rats treated or not with NAC were submitted to abdominal CO2 insufflation of 10 mmHg, at short and long periods of time of 1 and 3 h, respectively, and evaluated at 24, 72 h, and 1 wk after deinsufflation. Glomerular filtration rate (GFR) was measured by inulin clearance and oxidative stress was evaluated by serum thiobarbituric acid reactive substances (TBARS) Results No significant alterations in GFR were observed in normal animals submitted to the pneumoperitoneum of 1 h and evaluated after 24 h desufflation. With 3 h of pneumoperitoneum, a significant and progressive decrease in GFR occurred 24 and 72 h after desufflation with an increase in serum TBARS. GFR returned to normal levels a week later. In the NAC-treated rats, a complete protection against GFR drops was observed 24 and 72 h following 3 h of pneumoperitoneum associated with a decrease in TBARS. Conclusion These results suggest that NAC protects against acute kidney injury following prolonged pneumoperitoneum. These findings have significant clinical implications.

We investigated the effects of the antioxidant N-acetylcysteine (NAC) on early outcomes of deceased donor renal transplantation. Between April 2005 and June 2008, adult primary graft recipients of deceased renal donors were assigned to treatment (n = 38) or control (n = 36) groups and evaluated for 90 days and one year after renal transplantation. The treatment group received NAC orally (600 mg twice daily) from day 0 to 7 postoperatively. Renal function was determined by serum creatinine, MDRD and Cockcroft-Gault estimated GFR (eGFR), delayed graft function (DGF) and dialysis free Kaplan-Meier estimate curve. Serum levels of thiobarbituric acid reactive substances (TBARS), were employed as markers of oxidative stress. The NAC group displayed a lower mean serum creatinine during the first 90 days (P = .026) and at 1 year after transplantation (P = .005). Furthermore, the NAC group showed a higher mean eGFR throughout the first 90 days and at 1 year. DGF was lower among the NAC group (P = .017) and these recipients required fewer days of dialysis (P = .012). Oxidative stress was significantly attenuated with NAC (P < .001). Our results suggested that NAC enhanced early outcomes of deceased donor renal transplantation by attenuating oxidative stress.

Background/Aims: Hypomagnesemia may induce hypercholesterolemia, but the contrary has not been described yet. Thus, magnesium homeostasis was evaluated in rats fed a cholesterol-enriched diet for 8 days. This study has a relevant clinical application if hypomagnesemia, due to hypercholesterolemia, is confirmed in patients with long-term hypercholesterolemia. Methods: Both hypercholesterolemic (HC) and normocholesterolemic rats (NC) were divided into sets of experiments to measure hemodynamic parameters, physiological data, maximum capacity to dilute urine (CH2O), variations (Δ) in [Ca2+]i and the expression of transporter proteins. Results: HC developed hypomagnesemia and showed high magnesuria in the absence of hemodynamic abnormalities. However, the urinary sodium excretion and CH2O in HC was similar to NC. On the other hand, the responses to angiotensin II by measuring Δ [Ca2+]i were higher in the thick ascending limb of Henle’s loop (TAL) of HC than NC. Moreover, high expression of the cotransporter NKCC2 was found in renal outer medulla fractions of HC. Taken together, the hypothesis of impairment in TAL was excluded. Actually, the expression of the epithelial Mg2+ channel in renal cortical membrane fractions was reduced in HC. Conclusion: Impairment in distal convoluted tubule induced by hypercholesterolemia explains high magnesuria and hypomagnesemia observed in HC.

It currently is unknown whether creatine supplementation is safe for people with or at risk of kidney disease. We report on the short-term effects of creatine supplementation on kidney function in a young man with a single kidney and mildly decreased glomerular filtration rate (GFR). A 20-year-old man who had undergone unilateral nephrectomy and presented with mildly decreased GFR without kidney damage underwent a trial with 35 days of creatine supplementation (20 g/d for 5 days followed by 5 g/d for the next 30 days) and had his kidney function monitored. After the intervention, 51 Cr-EDTA clearance (pre, 81.6 mL/min/1.73 m 2 ; post, 82.0 mL/min/1.73 m 2 ), proteinuria (protein excretion: pre, 130 mg/d; post, 120 mg/d), and electrolyte levels were unchanged. Albuminuria, serum urea level, and estimated creatinine clearance were decreased (pre, 4.6 mg/d; post, 2.9 mg/d; pre, 37 mg/d; post, 28 mg/dL; and pre, 88 mL/min/1.73 m 2 ; post, 71 mL/min/1.73 m 2 , respectively), whereas serum creatinine level was slightly increased (pre, 1.03 mg/dL; post, 1.27 mg/dL), falsely suggesting kidney function impairment. This prospective report suggests that short-term creatine supplementation may not affect kidney function in an individual with a single kidney, mild decreased GFR, and ingesting a high-protein diet (ie, 2.8 g/kg/d). This finding has great relevance considering that creatine-induced kidney disease has been a growing concern, even for healthy people.

Acute renal failure following hemorrhagic shock was studied in awake rats. The animals were bled to maintain the mean arterial blood pressure between 40 and 60 mm Hg during 180 min. After this period, the blood was reinfused and the rats were studied 24 h later. Hemorrhagic shock caused a less intensive renal injury than 60-min bilateral renal artery clamping. Renal function in the latter model was worse (p less than 0.05) as shown by serum creatinine (SCr) (0.75 +/- 0.10 vs 1.2 +/- 0.2 mg/dL), blood urea nitrogen (BUN) (26.0 +/- 2.8 vs 53.0 +/- 8.5 mg/dL), fractional excretion of sodium (FENa, %) (0.3 +/- 0.1 vs 1.8 +/- 1.0) and potassium (FEK, %) (41.4 +/- 5.7 vs 76.3 +/- 14.2) and urine/plasma creatine (U/PCr (86.4 +/- 15.7 vs 38.8 +/- 15.5). The rats which received verapamil (10 micrograms/kg/min) prior and during the HS did not show increase in SCr (0.5 +/- 0.06 vs 0.75 +/- 0.1 mg/dL, p less than 0.05). This effect was also observed in the rats which received intravenous allopurinol (40 mg/kg) before HS, SCr did not increase (0.5 +/- 0.04 vs 0.75 +/- 0.1 mg/dL, p = 0.05), suggesting a protective effect of those substances in HS.(ABSTRACT TRUNCATED AT 250 WORDS)

OBJECTIVE: To identify prediction factors for the development of leptospirosis-associated pulmonary hemorrhage syndrome (LPHS). METHODS: We conducted a prospective cohort study. The study comprised of 203 patients, aged > or =14 years, admitted with complications of the severe form of leptospirosis at the Emilio Ribas Institute of Infectology (Sao Paulo, Brazil) between 1998 and 2004. Laboratory and demographic data were obtained and the severity of illness score and involvement of the lungs and others organs were determined. Logistic regression was performed to identify independent predictors of LPHS. A prospective validation cohort of 97 subjects with severe form of leptospirosis admitted at the same hospital between 2004 and 2006 was used to independently evaluate the predictive value of the model. RESULTS: The overall mortality rate was 7.9%. Multivariate logistic regression revealed that five factors were independently associated with the development of LPHS: serum potassium (mmol/L) (OR = 2.6; 95% CI = 1.1-5.9); serum creatinine (micromol/L) (OR = 1.2; 95% CI = 1.1-1.4); respiratory rate (breaths/min) (OR = 1.1; 95% CI = 1.1-1.2); presenting shock (OR = 69.9; 95% CI = 20.1-236.4), and Glasgow Coma Scale Score (GCS) < 15 (OR = 7.7; 95% CI = 1.3-23.0). We used these findings to calculate the risk of LPHS by the use of a spreadsheet. In the validation cohort, the equation classified correctly 92% of patients (Kappa statistic = 0.80). CONCLUSIONS: We developed and validated a multivariate model for predicting LPHS. This tool should prove useful in identifying LPHS patients, allowing earlier management and thereby reducing mortality.

Tubulointerstitial nephritis is a common clinicopathological finding in leptospirosis. Clinically, nonoliguric acute kidney injury (AKI), hypokalemia, sodium, and magnesium wasting frequently occur in leptospirosis. The exact mechanisms of renal involvement remain largely unclear. Immunohistochemistry to detect expression of the endogenous sodium/hydrogen exchanger isoform 3 (NHE 3), aquaporin 1 and 2, alpha-Na(+)K(+)ATPase, and sodium-potassium-chloride cotransporter in its NKCC2 isoform was performed on kidneys removed during autopsy of human leptospirosis cases and kidneys removed during autopsy of human non-leptospirosis cases with and without evidence of acute tubular necrosis (ATN). A decrease in NHE 3, aquaporin 1, and alpha-Na(+)K(+)ATPase expression occurred in proximal convoluted tubule cells. Expression of aquaporin 1 was preserved along the descending thin limb of the loop of Henle in the outer medulla. alpha-Na(+)K(+)ATpase expression was essentially preserved in the distal tubules, i.e., the thick ascending limb of the loop of Henle, macula densa, and distal convoluted tubule. Aquaporin 2 expression in the collecting tubules was enhanced compared to those of non-leptospirotic kidneys. NKCC2 cotransport isoform was expressed in the thick ascending limb of the loop of Henle and was essentially preserved in leptospirotic kidneys. Primary injury of the proximal convoluted tubules is regarded as the hallmark of the kidney in leptospirosis. Sodium and water transport are particularly affected with increased distal potassium excretion, hypokalemia, and polyuria. Enhanced expression of aquaporin 2 in medullary collecting tubules is probably an attempt to retain water during the nonoliguric phase of renal failure.

The objective of the present study was to determine the prevalence of electrolyte disturbances in AIDS patients developing acute kidney injury in the hospital setting, as well as to determine whether such disturbances constitute a risk factor for nephrotoxic and ischemic injury. A prospective, observational cohort study was carried out. Hospitalized AIDS patients were evaluated for age; gender; coinfection with hepatitis; diabetes mellitus; hypertension; time since HIV seroconversion; CD4 count; HIV viral load; proteinuria; serum levels of creatinine, urea, sodium, potassium and magnesium; antiretroviral use; nephrotoxic drug use; sepsis; intensive care unit (ICU) admission, and the need for dialysis. Each of these characteristics was correlated with the development of acute kidney injury, with recovery of renal function and with survival. Fifty-four patients developed acute kidney injury: 72% were males, 59% had been HIV-infected for5 years, 72% had CD4 counts200 cells/mm(3), 87% developed electrolyte disturbances, 33% recovered renal function, and 56% survived. ICU admission, dialysis, sepsis and hypomagnesemia were all significantly associated with nonrecovery of renal function and with mortality. Nonrecovery of renal function was significantly associated with hypomagnesemia, as was mortality in the multivariate analysis. The risks for nonrecovery of renal function and for death were 6.94 and 6.92 times greater, respectively, for patients with hypomagnesemia. In hospitalized AIDS patients, hypomagnesemia is a risk factor for nonrecovery of renal function and for in-hospital mortality. To determine whether hypomagnesemia is a determinant or simply a marker of critical illness, further studies involving magnesium supplementation in AIDS patients are warranted.

Sirolimus, an antiproliferative immunosuppressant, induces hypomagnesemia and hypokalemia. Rosiglitazone activates renal sodium- and water-reabsorptive pathways. We evaluated whether sirolimus induces renal wasting of magnesium and potassium, attempting to identify the tubule segments in which this occurs. We tested the hypothesis that reduced expression of the cotransporter NKCC2 forms the molecular basis of this effect and evaluated the possible association between increased urinary excretion of magnesium and renal expression of the epithelial Mg2+channel TRPM6. We then analyzed whether rosiglitazone attenuates these sirolimus-induced tubular effects. Wistar rats were treated for 14 days with sirolimus (3 mg/kg body wt in drinking water), with or without rosiglitazone (92 mg/kg body wt in food). Protein abundance of NKCC2, aquaporin-2 (AQP2), and TRPM6 was assessed using immunoblotting. Sirolimus-treated animals presented no change in glomerular filtration rate, although there were marked decreases in plasma potassium and magnesium. Sirolimus treatment reduced expression of NKCC2, and this was accompanied by greater urinary excretion of sodium, potassium, and magnesium. In sirolimus-treated animals, AQP2 expression was reduced. Expression of TRPM6 was increased, which might represent a direct stimulatory effect of sirolimus or a compensatory response. The finding that rosiglitazone prevented or attenuated all sirolimus-induced renal tubular defects has potential clinical implications.

The present study was carried out to examine the effect of chronic dietary protein restriction on renal water handling in the rat. During hypotonic saline infusion, the malnourished rats showed a lower free-water clearance, corrected by inulin clearance (7.2 ± 0.4%), than normal rats (13.6 ± 2.5%, p H2o) corrected by inulin clearance was lower in malnourished rats (6.62 ± 0.64%) than in control animals (9.25 ± 0.62, p H2o was referred to the osmolar clearance, malnourished animals showed lower values than normal. These results suggest a defect in NaCl transport in the thick ascending limb of Henle. In vitro measurements of diffusional water permeability (PDW) in the inner medullary collecting duct (IMCD) obtained from malnourished rats showed an increase from 40.0 ± 5.4 × 10-5 cm/s to 71.3 ± 5.4 × 10-5 cm/s by adding maximum effective concentration (50 μU/ml) of arginine vasopressin (VP) to the bath. These values were not different from the PDW observed in the IMCD of normal rats. In another series of microperfusion experiments, the hydraulic conductivity in IMCD of malnourished rats measured also in the presence of maximum effective concentration of VP was 29.7 ± 3.4 × 10-6 cm/atm/s, a mean value not significantly different from that observed in the IMCD of normal rats (35.2 ± 4.3 × 10-6 cm/atm/s). However, the Lp stimulated by submaximum effective doses of VP (1 and 10 μU/ml) was significantly lower in the IMCD of malnourished than normal rats. These findings indicate that the concentration defect observed in malnourished rats was due to a defect in NaCl transport in the thick ascending limb of Henle, and a partial resistance of IMCD to VP-stimulated water permeability.

Forty-two consecutive patients with leptospirosis and acute lung injury who were mechanically ventilated were analyzed in a prospective cohort study. Nineteen patients (45%) survived, and 23 (55%) died. Multivariate analysis revealed that 3 variables were independently associated with mortality: hemodynamic disturbance (odds ratio [OR], 6.0; 95% confidence interval [CI], 0.9‐38.8; ), serum creatinine level 1265.2 mmol/L (OR, 10.6; 95% CI, 0.9‐123.7; P= .047 ), and serum potassium level 14.0 mmol/L (OR, 19.9; 95% CI, 1.2‐342.8; ). P= .026 P= .009 These observations can be used to identify factors associated with mortality early in the course of severe respiratory failure in leptospirosis. Leptospirosis is a zoonosis that causes a wide spectrum of clinical manifestations in humans [1‐3]. Deaths are usually associated with severe jaundice, oliguric renal failure, and hemorrhage manifestations [4‐7]. A recent study described an outbreak of leptospirosis with cases of pulmonary hemorrhage in Central America [3]. The objective of this study was to identify factors associated with mortality in patients with acute lung injury due to leptospirosis.

Leptospirosis is recognized as a globally re-emerging zoonosis. Interstitial nephritis is the principal feature of the disease. Leptospirosis-induced acute kidney injury typically is nonoliguric and includes hypokalemia. Tubular function alterations precede a decrease in the glomerular filtration rate, which could explain the high frequency of hypokalemia. Studies in human beings and animals have shown increased urinary fractional excretion of potassium and sodium, as well as an increased potassium/sodium ratio, suggesting increased distal potassium secretion caused by increased distal sodium delivery consequent to functional impairment of proximal sodium reabsorption. Confirming these findings, Western blot studies have shown lower renal expression of the sodium/hydrogen exchanger isoform 3 and of aquaporin 2, together with higher renal expression of the Na-K-2Cl cotransporter NKCC2, in infected animals. The severe form (Weil's disease) manifests as diffuse alveolar hemorrhage, pulmonary edema, acute respiratory distress syndrome, or a combination of these features, accompanied by acute kidney injury and can be highly lethal. Antibiotic treatment is efficient in the early and late/severe phases. For critically ill leptospirosis patients, the following are recommended: daily hemodialysis, low daily net fluid intake (because of the risk for pulmonary hemorrhage), and lung-protective strategies (low tidal volumes and high positive end-expiratory pressures after recruitment maneuvers).

Background. Obstructive nephropathy decreases renal blood flow (RBF) and glomerular filtration rate (GFR), causing tubular abnormalities, such as urinary concentrating defect, as well as increasing oxidative stress. This study aimed to evaluate the effects of N-acetylcysteine (NAC) on renal function, as well as on the protein expression of aquaporin 2 (AQP2) and endothelial nitric oxide synthase (eNOS), after the relief of bilateral ureteral obstruction (BUO). Methods. Adult male Wistar rats were divided into four groups: sham (sham operated); sham operated + 440 mg/kg body weight (BW) of NAC daily in drinking water, started 2 days before and maintained until 48 h after the surgery; BUO (24-h BUO only); BUO + NAC-pre (24-h BUO plus 440 mg/kg BW of NAC daily in drinking water started 2 days before BUO); and BUO + NAC-post (24-h BUO plus 440 mg/kg BW of NAC daily in drinking water started on the day of BUO relief). Experiments were conducted 48 h after BUO relief. Results. Serum levels of thiobarbituric reactive substances, which are markers of lipid peroxidation, were significantly lower in NAC-treated rats than in the BUO group rats. The administration of NAC provided significant protection against post-BUO GFR drops and reductions in RBF. Renal cortices and BUO rats presented decreased eNOS protein expression of eNOS in the renal cortex of BUO group rats, whereas it was partially recovered in BUO + NAC-pre group rats. Urine osmolality was significantly lower in BUO rats than in sham group rats or NAC-treated rats, the last also presenting less interstitial fibrosis. Post-BUO downregulation of AQP2 protein expression was averted in the BUO + NAC-pre group rats. Conclusions. This study demonstrates that NAC administration ameliorates the renal function impairment observed 48 h after the relief of 24-h BUO. Oxidative stress is important for the suppression of GFR, RBF, tissue AQP2 and eNOS in the polyuric phase after the release of BUO.

Severe leptospirosis with pulmonary hemorrhage is emerging globally. Measures to control leptospirosis through sanitation depend on accurate case finding and reporting. Rapid death certificate reporting, plus necropsy of persons who died of leptospirosis, facilitates public health intervention and could provide an important tool in assessing the global burden of leptospirosis.

Tubular dysfunction is a hallmark of severe leptospirosis. Antimicrobial therapy is thought to interfere on renal involvement. We evaluated the expression of a proximal tubule type-3 Na + /H + exchanger (NHE3) and a thick ascending limb Na + -K + -2Cl - co-transporter (NKCC2) in controls and treated hamsters. Animals infected by a serovar Copenhageni isolate, were treated or not with ampicillin (AMP) and/or N-acetylcysteine (NAC). Leptospiral antigen(s) and expression of renal transporters were evaluated by immunohistochemistry, and serum thiobarbituric acid (TBARS) was quantified. Infected hamsters had high amounts of detectable leptospiral antigen(s) in target tissues while renal expression of NHE3 and NKCC2 decreased. Ampicillin treatment was associated with minimal or no detection of leptospiral antigens, normal expression of NHE3 and NKCC2 transporters, and reduced levels of TBARS. NAC effect was restricted to lowering TBARS. Early and late AMP treatment rescued tubular defects in severe leptospirosis disease, and there was no evidence of benefit from antioxidant therapy.

A previously healthy seven-year-old boy was admitted to the intensive care unit because of toxaemia associated with varicella. He rapidly developed shock and multisystem organ failure associated with the appearance of a deep-seated soft tissue infection and, despite aggressive treatment, died on hospital day 4. An M-non-typable, spe A and spe B positive Group A Streptococcus was cultured from a deep soft tissue aspirate. The criteria for defining Streptococcal toxic shock-like syndrome were fulfilled. The authors discuss the clinical and pathophysiological aspects of this disease as well as some unusual clinical findings related to this case.

Creatine (CR) supplementation is commonly used by athletes. However, its effects on renal function remain controversial. The aim of this study was to evaluate the effects of creatine supplementation on renal function in healthy sedentary males (18-35 years old) submitted to exercise training. A randomized, double-blind, placebo-controlled trial was performed. Subjects (n = 18) were randomly allocated to receive treatment with either creatine (CR) ( approximately 10 g day(-1) over 3 months) or placebo (PL) (dextrose). All subjects undertook moderate intensity aerobic training, in three 40-min sessions per week, during 3 months. Serum creatinine, serum and urinary sodium and potassium were determined at baseline and at the end of the study. Cystatin C was assessed prior to training (PRE), after 4 (POST 4) and 12 weeks (POST 12). Cystatin C levels (mg L(-1)) (PRE CR: 0.82 +/- 0.09; PL: 0.88 +/- 0.07 vs. POST 12 CR: 0.71 +/- 0.06; PL: 0.75 +/- 0.09, P = 0.0001) were decreased over time, suggesting an increase in glomerular filtration rate. Serum creatinine decreased with training in PL but was unchanged with training in CR. No significant differences were observed within or between groups in other parameters investigated. The decrease in cystatin C indicates that high-dose creatine supplementation over 3 months does not provoke any renal dysfunction in healthy males undergoing aerobic training. In addition, the results suggest that moderate aerobic training per se may improve renal function.

In patients with meningococcal infection, devastating presentations, such as purpura fulminans, which can progress to extensive tissue necrosis of the limbs and digits, have a significant social impact. The case presented herein illustrates such a phenomenon in a patient who developed bilateral necrosis of the lower extremities as a result of infection with Neisseria meningitis. We emphasize that severe myalgia was the first clinical manifestation of meningococcal purpura fulminans in our case. However, myalgia has typically been overlooked and undervalued as an early clinical feature of meningococcal sepsis. Early recognition and prompt initial antibiotic therapy continue to be the cornerstones of the successful management of this dramatic disease, reducing morbidity and mortality.

A number of studies conducted in humans and in animals have observed that events occurring early in life are associated with the development of diseases in adulthood. Salt overload and restriction during pregnancy and lactation are responsible for functional (hemodynamic and hormonal) and structural alterations in adult offspring. Our group observed that lower birth weight and insulin resistance in adulthood is associated with salt restriction during pregnancy. On the other hand, perinatal salt overload is associated with higher blood pressure and higher renal angiotensin II content in adult offspring. Therefore, we hypothesised that renin–angiotensin system (RAS) function is altered by changes in sodium intake during pregnancy. Such changes may influence fetoplacental blood flow and thereby fetal nutrient supply, with effects on growth in utero and, consequently, on birth weight. Female Wistar rats were fed low-salt (LS), normal-salt (NS), or high-salt (HS) diet, starting before conception and continuing until day 19 of pregnancy. Blood pressure, heart rate, fetuses and dams' body weight, placentae weight and litter size were measured on day 19 of pregnancy. Cardiac output, uterine and placental blood flow were also determined on day 19. Expressions of renin–angiotensin system components and of the TNF-alpha gene were evaluated in the placentae. Plasma renin activity (PRA) and plasma and tissue angiotensin-converting enzyme (ACE) activity, as well as plasma and placental levels of angiotensins I, II, and 1–7 were measured. Body weight and kidney mass were greater in HS than in NS and LS dams. Food intake did not differ among the maternal groups. Placental weight was lower in LS dams than in NS and HS dams. Fetal weight was lower in the LS group than in the NS and HS groups. The PRA was greater in LS dams than in NS and HS dams, although ACE activity (serum, cardiac, renal, and placental) was unaffected by the level of sodium intake. Placental levels of angiotensins I and II were lower in the HS group than in the NS and LS groups. Placental angiotensin receptor type 1 (AT1) gene expression and levels of thiobarbituric acid reactive substances (TBARS) were higher in HS dams, as were uterine blood flow and cardiac output. The degree of salt intake did not influence plasma sodium, potassium or creatinine. Although fractional sodium excretion was higher in HS dams than in NS and LS dams, fractional potassium excretion was unchanged. In conclusion, findings from this study indicate that the reduction in fetal weight in response to salt restriction during pregnancy does not involve alterations in uterine-placental perfusion or the RAS. Moreover, no change in fetal weight is observed in response to salt overload during pregnancy. However, salt overload did lead to an increase in placental weight and uterine blood flow associated with alterations in maternal plasma and placental RAS. Therefore, these findings indicate that changes in salt intake during pregnancy lead to alterations in uterine-placental perfusion and fetal growth.

Background: Leptospirosis is a public health problem, the severe form of which (Weil9s disease) includes acute respiratory distress syndrome, typically accompanied by acute kidney injury (AKI), and is associated with high mortality rates. Recent evidence suggests that dialysis dosage affects outcomes in critically ill patients with sepsis-induced AKI. However, this population varies widely in terms of age, gender, and concomitant conditions, making it difficult to determine the appropriate timing (door-to-dialysis time) and dialysis dosage. Design, setting, participants, and measurements: It is logical to assume that increasing the dialysis dosage would minimize uremic complications and improve outcomes in such patients. Patients with Weil9s disease constitute a homogeneous population and are typically free of comorbidities, therefore presenting an ideal model in which to test this assumption. Results: The effects of dialysis dosage were evaluated in this population, with the use of either classic or slow low-efficiency hemodialysis, and two periods/treatment plans were compared: 2002 to 2003/delayed, alternate-day dialysis (DAdD group; n = 15) and 2004 to 2005/prompt and daily dialysis (PaDD group; n = 18). Age, gender, AKI severity, APACHE score, serum urea, and time to recovery of renal function were assessed. All patients received vasoactive drugs (because of hemodynamic instability) and were on mechanical ventilation (because of acute respiratory distress syndrome). Mean serum urea during the dialysis period was significantly lower in the PaDD group than in the DAdD group. Of the PaDD group patients, three (16.7%) died, compared with 10 (66.7%) of the DAdD group patients. Conclusions: On the basis of this result, it is believed that alternate-day hemodialysis is no longer appropriate for critically ill patients with Weil9s disease.

Acute disseminated encephalomyelitis is a rare central nervous system demyelinating disease that occurs most frequently in children. It usually runs a monophasic course, beginning with fever, headache, and meningeal signs and rapidly progressing to coma when appropriate diagnosis and treatment are not provided. We report a case of a 14-year-old patient to alert emergency physicians to consider acute disseminated encephalomyelitis when presented with any child with encephalitic signs with nonspecific cerebrospinal fluid findings, failure to detect any causative agent, and only mild alterations on computerized tomography scan. The role of magnetic resonance imaging for the diagnosis is emphasized.

Leptospirosis is a public health problem worldwide. Severe leptospirosis manifests as pulmonary edema leading to acute respiratory distress syndrome and polyuric acute renal failure (ARF). The etiology of leptospirosis-induced pulmonary edema is unclear. Lung edema clearance is largely affected by active sodium transport out of the alveoli rather than by reversal of the Starling forces. The objective of this study was to profile leptospirosis-induced ARF and pulmonary edema. We inoculated hamsters with leptospires and collected 24-h urine samples on postinoculation day 4. On day 5, the animals were killed, whole blood was collected, and the kidneys and lungs were removed. Immunoblotting was used to determine expression and abundance of water and sodium transporters. Leptospirosis-induced ARF resulted in natriuresis, lower creatinine clearance, and impaired urinary concentrating ability. Renal expression of the sodium/hydrogen exchanger isoform 3 and of aquaporin 2 was lower in infected animals, whereas that of the Na-K-2Cl cotransporter NKCC2 was higher. Leptospirosis-induced lesions, predominantly in the proximal tubule, were responsible for the polyuria and natriuresis observed. The polyuria might also be attributed to reduced aquaporin 2 expression and the attendant urinary concentrating defect. In the lungs, expression of the epithelial sodium channel was lower, and NKCC1 expression was upregulated. We found that leptospirosis profoundly influences the sodium transport capacity of alveolar epithelial cells and that impaired pulmonary fluid handling can impair pulmonary function, increasing the chance of lung injury. Greater knowledge regarding sodium transporter dysregulation in the lungs and kidneys can provide new perspectives on leptospirosis treatment.

We here report the case of a previously healthy 20-y-old male with disseminated meningococcal disease and purulent pericarditis. Polymerase chain reaction was used to identify Neisseria meningitidis serogroup C as the causative agent in the pericardial fluid.

Background Metabolic acidosis is highly prevalent in critically ill patients with acute renal failure. Little is known about the mechanisms by which renal replacement therapy intervenes in such cases. The objective of this study is to analyze the role of hemodialysis in acidosis correction in intensive care unit patients, with an emphasis on chloride levels in plasma and dialysate. Methods We studied 19 intermittent hemodialysis procedures in 17 acidotic patients. The patients were grouped by procedure type (conventional or sustained low-efficiency dialysis) and by predialysis plasma chloride level (higher or lower than the dialysate chloride concentration). Immediately before and after each procedure, blood samples were collected for biochemical analysis. The Stewart method was used to calculate the strong ion difference and strong ion gap. Results The patients presented acidosis related to hyperchloremia, hyperphosphatemia, and high unmeasured anions. Hypoalbuminemia had an alkalinizing effect. Hemodialysis corrected acidosis mainly by reducing phosphate and unmeasured anions. In the group as a whole, chloride levels did not change after dialysis. However, when analyzed according to predialysis plasma chloride, the high-chloride group presented a reduction in plasma chloride, resulting in better base excess improvement (Δ standard base excess) than in the low-chloride group. Among the determinants of acid-base status, the only factors correlating with Δ SBE were Δ strong ion gap and Δ chloride. Conclusion The serum chloride/dialysate chloride relationship during hemodialysis has an important impact on acidosis control.

Background/Aims: Patients severely dehydrated from diarrhea are at risk of developing hyperkalemia consequent to fluid therapy treatment. In parallel with the regulation of external potassium balance by the kidney and gastrointestinal tract, plasma potassium is rapidly regulated by redistribution of potassium between the extracellular and intracellular compartments. Erythrocytes contain ATPases that play a role in this potassium movement. In this study, erythrocyte ATPase effectiveness was evaluated in infants dehydrated from diarrhea and compared to that of healthy infants. Methods: Blood samples were collected from dehydrated and healthy infants. The activity of Na+,K+-ATPase and of an ouabain-insensitive K+-ATPase were assessed. Serum electrolytes and blood pH were also determined. Results: No hyperkalemia was found, even in dehydrated infants presenting with severe hyperchloremic metabolic acidosis. In the erythrocytes of dehydrated infants, Na+,K+-ATPase activity was increased correlating positively with the amount of sodium administered. High K+-ATPase activity in the erythrocytes correlated with low plasma potassium. The K+-ATPase activity correlated positively with the amount of potassium administered to dehydrated infants. Conclusion: These findings suggest that the erythrocytes Na+,K+-ATPase and K+-ATPase both protect against plasma potassium abnormalities in dehydrated infants. In such infants, the risk of hyperkalemia is probably low.

Background and Aims: Primary biliary cirrhosis (PBC) might be complicated by osteoporosis, whose etiology remains unknown but seems to be multifactorial. Prevalence rates of 30% to 60% for distal renal tubular acidosis (DRTA) have been reported in PBC patients, generally as incomplete DRTA. Although it is undisputed that a reduced bone mineral density (BMD) is the expected outcome among patients who have been suffering from longstanding chronic metabolic acidosis, it is unclear if incomplete DRTA is also associated with metabolic bone disease in PBC patients. The present study was undertaken to compare the BMD of PBC patients with and without DRTA. Methods: The BMD of 23 PBC patients (11 with DRTA and 12 without), all with normal clearance of creatinine, was assessed by dual energy radiograph absorptiometry. The diagnosis of DRTA was made if the urine pH was above 5.4 in all samples after the oral acid overload, showing tubular inability to acidify urine in the presence of test-induced systemic metabolic acidosis. Results: Densitometric signs of osteoporosis were found in 82% of DRTA cases and in 83% of patients without DRTA (difference not significant). There were no significant differences in BMD measurement, T and Z scores of patients with and without DRTA. Conclusions: The present study could not support a correlation between the presence of DRTA and the bone loss observed in PBC patients.

Indinavir (IDV) is a protease inhibitor widely used in AIDS treatment. A sustained elevation of creatinine was identified in IDV-treated patients. We have previously demonstrated that IDV causes renal vasoconstriction in rats. The objective of this study was to investigate the mechanism of IDV-induced vasoconstriction and the effect that the vasodilator agents L-arginine (LA), nifedipine (NF), as well as magnesium supplementation (Mg), have on IDV-induced nephrotoxicity. Male Wistar rats were kept on fast overnight and given free access to water. IDV (80 mg/kg BW) and NF (3 mg/kg BW) were given by gavage for 15 days. LA (1.5%) and MgCl2 x 6H2O (1%) were added to drinking water. Six groups were studied: Control (n=6): normal rats treated with vehicle, a 0.05 M citric acid solution; IDV (n=7): IDV-treated rats; IDV+LA (n=6): IDV- and LA-treated rats; IDV+NF (n=7): IDV- and NF-treated rats; IDV+Mg (n=7): IDV- and MgCl2-treated rats; IDV+Mg+L-NAME (n=9): IDV- and MgCl2-treated rats, supplemented with L-NAME (2.5 mg/l in drinking water). Clearance studies and evaluations of urinary nitrite (NO2) excretion were performed on day 16. No changes in blood pressure were observed. NO2 excretion decreased in IDV-treated rats. LA and NF protected against IDV effects, improving GFR (IDV+LA, 1.95 +/- 0.10; IDV+NF, 1.94 +/- 0.07 vs IDV, 1.15 +/- 0.07 ml/min, P0.001) and RBF (IDV+LA, 7.83 +/- 0.09; IDV+NF, 7.63 +/- 0.14 vs IDV, 6.17 +/- 0.25 ml/min, P0.001). These results suggest that IDV-induced vasoconstriction is mediated by NO and Ca2+ channels. Magnesium also ameliorated GFR and RBF in IDV-treated rats (GFR IDV+Mg, 1.77 +/- 0.08 ml/min, P0.001; RBF IDV+Mg, 7.35 +/- 0.158 ml/min, P0.001). Magnesium protection is not NO-mediated since it was not blocked by L-NAME. In conclusion, LA, NF and Mg protect against IDV-induced nephrotoxicity in rats. This study may have potential clinical implications for prevention of IDV-induced nephrotoxicity.