Loxosceles venom-induced cytokine activation, hemolysis, and acute kidney injury.

Herein, we describe a confirmed case of Loxosceles spider bite that illustrates the critical complications seen in loxoscelism, including skin necrosis, rhabdomyolysis, hemolysis, coagulopathy, acute kidney failure, and electrolyte disorders. Upon initial assessment, laboratory studies revealed the following: the white blood cell count was 29,400 WBCs/mm(3), hemoglobin was 9.2g/dL, and the platelet count was 218,000 cells/mm(3). Coagulation studies revealed the following: international normalized ratio, 1.83; activated partial-thromboplastin time, 62 s; D-dimer, 600 ng/mL (normal range <500 ng/mL); free protein S, 37% (normal range=64-114%); protein C, negative; and antithrombin III, negative. Various serum levels were abnormal: urea, 110 mg/dL; creatinine, 3.1mg/dL; indirect bilirubin, 3.8 mg/dL; creatine kinase, 1631 U/L; lactate dehydrogenase, 6591 U/L; potassium 6.2 mmol/L. Urine tests were positive for hemoglobin and bilirubin. In addition, concentrations of interleukin-6 and tumor necrosis factor-alpha were notably elevated in the serum. In conclusion, physicians must be alert to the possibility of loxoscelism when a patient presents with the clinical and laboratory findings described above, especially if the patient resides in an endemic area. Advances in our understanding of multiple pathways and mediators that orchestrate the response to Loxosceles venom might reveal new possibilities for the management of loxoscelism.

Vitamin D intoxication: a cause of hypocalcaemia and acute renal failure in a HIV patient.

Hypercalcaemia in patients with HIV infection is usually associated with specific conditions such as lymphoma and granulomatous diseases. We described a case of severe hypercalcaemia consequent to vitamin D intoxication and secondary renal failure in a HIV patient under tenofovir using. Serum creatinine and calcium returned to near normal levels after vitamin D discontinuation, saline and furosemide administration. Some aspects of the drug-induced nephropathy are discussed.

Urinary NO3 excretion and renal failure in indinavir-treated patients.

Treatment with indinavir (IDV), a protease inhibitor, is frequently associated with renal abnormalities. We determined the incidence of renal failure (creatinine clearance <80 mL min-1 1.73 (m(2))-1) in HIV patients treated with highly active antiretroviral therapy, including IDV, and investigated the possible mechanisms and risk factors of IDV nephrotoxicity. Thirty-six patients receiving IDV were followed for 3 years. All were assessed for age, body weight, duration of infection, duration of IDV treatment, sulfur-derivative use, total cholesterol, triglycerides, magnesium, sodium, potassium, creatinine, and urinalysis. We also determined renal function in terms of creatinine clearance, urine osmolality and fractional excretion of sodium, potassium, and water. Urinary nitrate (NO3) excretion was measured in 18 IDV-treated patients and compared with that of 8 patients treated with efavirenz, a drug without renal side effects. Sterile leukocyturia occurred in 80.5% of the IDV-treated patients. Creatinine clearance <80 mL min-1 1.73 (m(2))-1 was observed in 22 patients (61%) and was associated with low body weight and the use of sulfur-derivatives. These patients also had lower osmolality, lower urine volume and a higher fractional excretion of water compared to the normal renal function group. Urinary NO3 excretion was significantly lower in IDV-treated patients (809 +/- 181 microM NO3-/mg creatinine) than in efavirenz-treated patients (2247 +/- 648 microM NO3-/mg creatinine, P < 0.01). The lower NO3 excretion suggests that IDV decreases nitric oxide production.

Protective effect of L-arginine on hypercholesterolemia-enhanced renal ischemic injury.

The effects of hypercholesterolemia on ischemic renal failure were evaluated in rats subjected to 60 min of left renal artery clamping and contralateral nephrectomy. One group of rats (HC) was kept on a cholesterol-supplemented diet for 3 weeks before renal injury and compared to a group fed a regular diet (ND). Two days after renal ischemia, inulin clearance (C(in), ml/min per 100 g BW) was lower in HC-rats (0.033 +/- 0.011) than in ND-rats (0.227 +/- 0.037; P < 0.01). indicating that hypercholesterolemia potentiated renal ischemic injury. Twenty-one days after renal ischemia the C(in) of HC-rats did not differ from ND-rats, suggesting that hypercholesterolemia did not limit late recovery. Since nitric oxide production is impaired in HC, L-arginine (50 mg/kg BW i.v.) was administered immediately after ischemia. Two days after ischemia, L-arg did not protect ND-rats from ischemia, while the C(in) and renal blood flow were higher in L-arg-treated HC rats than in untreated HC rats (C(in) = 0.125 +/- 0.013 rats vs. 0.033 +/- 0.011; P < 0.001) (RBF = 3.96 +/- 0.64 vs. 2.40 +/- 0.20 ml/min per 100 g BW; P < 0.05), indicating that L-arg protects HC rats from renal ischemia. The administration of D-arginine to ND rats induced a significant decrease of the C(in) and a significant increase of FE H2O, FE Na and FE K compared to the L-arginine and not treated groups. Cultures of inner medullary collecting duct cells from ND rats were resistant to 24-h hypoxia. In contrast, IMCD cell cultures from HC rats showed higher LDH release after 24-h hypoxia than normoxic cells (69.2 +/- 3.4 vs. 30.9 +/- 3.6%, P < 0.001); 1 mM L-arg added to the medium attenuated LDH release (44.3 +/- 2.4%, P < 0.01). These data demonstrate that HC predisposes renal tubular cells to hypoxic injury and L-arg protects cells of HC.

L-Arginine and allopurinol protect against cyclosporine nephrotoxicity.

The role of nitric oxide (NO) and oxygen free radicals in cyclosporine (CsA) nephrotoxicity was investigated using L-arginine, an NO substrate, and allopurinol, a xanthine oxidase inhibitor (involved in the formation of oxygen radicals) in an experimental model with Wistar rats. CsA, administered at 15 mg/kg/body weight (BW) subcutaneously for 10 days, caused a decrease in glomerular filtration rate, with inulin clearance of 0.33+/-0.04 vs. 1.11+/-0.06 ml/min/100 g BW (P<0.01 vs. control). L-Arginine, 1.5% in drinking water 5 days before and during CsA administration, partially protected the animals against this fall in glomerular filtration rate, with inulin clearance of 0.68+/-0.03 ml/min/100 g BW (P<0.01 vs. CsA). Allopurinol, at 10 mg/kg/BW by gavage, also had a protective action, with inulin clearance of 0.54+/-0.04 ml/min/100 g (P<0.01 vs. CsA). CsA caused an elevation in NO production, as assessed by urinary excretion of its metabolites, nitrite and nitrate (NO2 and NO3; 0.836+/-0.358 vs. 0.107+/-0.019 nmol/microg creatinine). NO production was as much as threefold higher in the L-arginine group (1.853+/-0.206 nmol/g creatinine). This CsA effect is probably related to its vasoconstrictive stimulus. Supplementation with L-arginine, which provides more substrate for NO formation, may enhance vasodilatation and consequently reduce the impairment of renal function. The protection provided by allopurinol may be related to the reduced formation of oxygen radicals, preventing the deleterious effects of lipid peroxidation.

Peculiar electrolytic and hormonal abnormalities in acute renal failure due to 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.

Cellular immune response analysis of patients with leptospirosis.

Peripheral blood mononuclear cells (PBMC) from acute leptospirosis patients with and without acute renal failure were studied in order to investigate the status of cellular immunity in this disease. We analyzed the lymphocyte subsets of leptospirosis patients by immunofluorescence and their responsiveness to the mitogens phytohemagglutinin (PHA) and pokeweed mitogen (PWM). Additionally, we investigated the effect of the patients' sera on normal PBMC proliferative response. We observed a decrease in the CD3+ and CD4+ cell subsets in patients with and without acute renal failure, or in percentage values alone in those who had recovered from renal failure. An increase in the number of B lymphocytes was observed in all patients, compared with controls. This increase in B lymphocytes was seen even in patients who had recovered from renal failure, when the number of CD3+ and CD4+ lymphocytes had already returned to normal levels. The low PHA response observed only with lymphocytes from patients with acute renal failure suggests a suppressive effect. The proliferative response to PWM was comparable to controls, even in the patients with acute renal failure. This latter result and the expansion of the B cell number could be related to leptospiral-derived factor(s). We also showed that sera from patients with and without acute renal failure exerted some inhibitory activity on normal PBMC responses to PHA and PWM. Although the redistribution of lymphocyte subsets and the serum suppressor activity were related to acute renal failure and leptospiral factor(s), we suggest that the cellular immune system was not irreversibly affected, which is compatible with the good prognosis seen in the patients studied.

Outcome of leptospirosis in children.

We conducted a retrospective analysis of 43 consecutive children (35 boys and 8 girls), 4-14 years of age and living in an urban area, who were hospitalized at the Instituto de Infectologia Emilio Ribas (Sao Paulo, Brazil) from January 1989 to December 1995 with an acute illness subsequently diagnosed as leptospirosis. Epidemiologic data indicated contact with contaminated water in most cases (88%). The patient sera reacted most strongly with Leptospira interrogans serovars copenhageni (45%) and icterohaemorrhagiae (32.7%). Jaundice was present in 70% of the patients, elevated transaminase levels in 56%, renal failure in 79%, meningitis in 23%, thrombocytopenia in 65%, and hemorrhagic manifestations in 11.6%. Three children had pulmonary hemorrhage with respiratory failure and one death occurred as a consequence of respiratory failure. We also observed that antimicrobial therapy reduced the extent of renal failure and thrombocytopenia. These data indicate that antibiotics benefit children with late, severe leptospirosis and that severe disease also occurs in children and should be considered in the differential diagnosis.

The role of potassium in the regulation of adenosine production by ATP-diphosphohydrolase on the endothelial cell membrane.

Endothelial cells have ectonucleotidases that catabolize extracellular nucleotides and are sensitive to the presence of cations. Our aim was to determine whether the metabolism of extracellular nucleotides is influenced by exposure of endothelial cells to high potassium relevant to human pathophysiology. Human umbilical vein endothelial cells were incubated with 25 mM potassium and without potassium. The metabolism of radioactive substrates was measured and activities were 7.0+/-1.3 and 12.2+/-1.4 microM P/h/mg of protein with and without potassium. Also incubation with membrane pellet from endothelial cells was used, this assay showed 15.5+/-1.9 and 20.9+/-0.7 microM P/ h/mg of protein with and without potassium, respectively. HPLC analysis of supernatant showed that AMP production was lower in the presence of 25 mM potassium. Analysis of different potassium levels showed that a progressive reduction occurred above 10 mM potassium. We conclude those potassium levels above 10 mM, which can be found in ischemia, inhibit the catabolism of extracellular adenine nucleotides by the ectonucleotidases of endothelial cells and may thus modify the pathophysiology of ischemia-reperfusion injury.

Effects of hypokalemia and hypomagnesemia on zidovudine (AZT) and didanosine (ddI) nephrotoxicity in rats.

BACKGROUND: Zidovudine (AZT) and didanosine (ddI) are antiretroviral drugs widely used in AIDS patients. Hypokalemia and hypomagnesemia are frequently encountered in AIDS patients using AZT and/or ddI. OBJECTIVE: To verify the effects of AZT and ddI on rat renal function submitted to normal diet, low potassium diet and magnesium-free diet. METHODS: Glomerular filtration rate and renal hemodynamic were measured in Wistar rats submitted to a normal or a potassium-depleted diet. The animals were given AZT, ddI for 15 days. Six groups of rats were studied: normal diet, normal diet + AZT, normal diet + ddI, low K diet, low K diet + AZT and low K diet + ddI. Three additional groups of rats submitted to magnesium depletion for 15 days were also studied: magnesium-free diet, magnesium-free diet + AZT and magnesium-free diet + ddI. RESULTS: AZT and didanosine did not modify renal function of rats on a normal diet. However, in hypokalemic rats, both drugs produced a decrease in glomerular filtration rate and in renal blood flow consequent to renal vasoconstriction and associated with alterations in tubular function (characterized by an increased fractional excretion of sodium). Hypomagnesemia induced a decrease in glomerular filtration rate and in renal blood flow only in AZT-treated rats. CONCLUSION: Our data suggest that hypokalemia predisposes to AZT and ddI nephrotoxicity, while hypomagnesemia predisposes only to AZT nephrotoxicity. Thus, chronic AZT and ddI administration may produce acute renal failure in AIDS patients with hypokalemia and/or hypomagnesemia. Serum K and Mg levels should be carefully monitored in these patients.

Effect of cyclooxygenase inhibitors on gentamicin-induced nephrotoxicity in rats.

The frequent use of nonsteroidal anti-inflammatory drugs (NSAID) in combination with gentamicin poses the additional risk of nephrotoxic renal failure. Cyclooxygenase-1 (COX-1) is the main enzyme responsible for the synthesis of renal vasodilator prostaglandins, while COX-2 participates predominantly in the inflammatory process. Both are inhibited by non-selective NSAID such as indomethacin. Selective COX-2 inhibitors such as rofecoxib seem to have fewer renal side effects than non-selective inhibitors. The objective of the present study was to determine whether the combined use of rofecoxib and gentamicin can prevent the increased renal injury caused by gentamicin and indomethacin. Male Wistar rats (250-300 g) were treated with gentamicin (100 mg/kg body weight, ip, N = 7), indomethacin (5 mg/kg, orally, N = 7), rofecoxib (1.4 mg/kg, orally, N = 7), gentamicin + rofecoxib (100 and 1.4 mg/kg, respectively) or gentamicin + indomethacin (100 and 5 mg/kg, respectively, N = 8) for 5 days. Creatinine clearance and alpha-glutathione-S-transferase concentrations were used as markers of renal injury. Animals were anesthetized with ether and sacrificed for blood collection. The use of gentamicin plus indomethacin led to worsened renal function (0.199 +/- 0.019 ml/min), as opposed to the absence of a nephrotoxic effect of rofecoxib when gentamicin plus rofexicob was used (0.242 +/- 0.011 ml/min). These results indicate that COX-2-selective inhibitors can be used as an alternative treatment to conventional NSAID, especially in situations in which risk factors for nephrotoxicity are present.

[Inhibitory effect of serum from rats with acute and chronic renal insufficiency on phagocytic activity in vitro]. / Efeito inibidor do soro de ratos com insuficiência renal aguda e crônica sobre a atividade fagocitária "in vitro".

The effect of serum obtained from rats with acute and chronic renal failure on phagocytosis was evaluated in macrophages cultured "in vitro". The erythrophagocytosis of these cells was lower after incubation with serum from rats with acute and chronic renal failure when compared to normal plasma. This inhibitory process persisted when the serum was previously filtered through a Millipore filter PM-30, but it was abolished when the serum was filtered through a Millipore filter PM-10. These data suggest that uremic plasma displays a inhibitory factor of phagocytic cells of a molecular weight between 10.000 and 30.000 daltons.

Fatal group A Streptococcal toxic shock-like syndrome in a child with varicella: report of the first well documented case with detection of the genetic sequences that code for exotoxins spe A and B, in São Paulo, Brazil.

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.

[Meningoencephalitis in the acute phase of measles. Report of 6 cases]. / Meningoencefalite na fase aguda do sarampo: relato de seis casos.

We present the clinical and laboratory manifestations of encephalitis following measles in six patients which were diagnosed during the epidemics that occurred in the city of São Paulo, Brazil, in 1997. We performed retrospective case analysis of the six patients diagnosed as having encephalitis due to measles. Encephalitis was diagnosed based on clinical grounds and on the cerebrospinal fluid (CSF) alterations. All the cases were serologically confirmed. Of 467 patients with measles who presented themselves for medical care at the Instituto de Infectologia Emílio Ribas six were diagnosed with encephalitis. Patient's age was 2 months to 28 years old. The most frequent symptoms were drowsiness and nuchal rigidity. CSF showed an increased of white cell count in all cases. Four patients were admitted to the intensive care unit. Two of them required mechanical ventilation. In only two patients did the computerized tomography show abnormalities. All showed good recovery without sequelae.

Protective effect of N-acetylcysteine on early outcomes of deceased renal transplantation.

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.

Hypomagnesemia is a risk factor for nonrecovery of renal function and mortality in AIDS patients with acute kidney injury.

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 for >5 years, 72% had CD4 counts <200 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.

Glomerular filtration is reduced by high tidal volume ventilation in an in vivo healthy rat model.

Mechanical ventilation has been associated with organ failure in patients with acute respiratory distress syndrome. The present study examines the effects of tidal volume (V(T)) on renal function using two V T values (8 and 27 mL/kg) in anesthetized, paralyzed and mechanically ventilated male Wistar rats. Animals were randomized into two groups of 6 rats each: V (T)8 (V(T), 8 mL/kg; 61.50 +/- 0.92 breaths/min; positive end-expiratory pressure, 3.0 cmH(2)O; peak airway pressure (PAW), 11.8 +/- 2.0 cmH(2)O), and V T27 (V(T), 27 mL/kg; 33.60 +/- 1.56 breaths/min; positive end-expiratory pressure, none, and PAW, 22.7 +/- 4.0 cmH(2)O). Throughout the experiment, mean PAW remained comparable between the two groups (6.33 +/- 0.21 vs 6.50 +/- 0.22 cmH(2)O). For rats in the V(T)27 group, inulin clearance (mL.min(-1).body weight(-1)) decreased acutely after 60 min of mechanical ventilation and even more significantly after 90 min, compared with baseline values (0.60 +/- 0.05 and 0.45 +/- 0.05 vs 0.95 +/- 0.07; P < 0.001), although there were no differences between groups in mean arterial pressure or gasometric variables. In the V(T)8 group, inulin clearance at 120 min of mechanical ventilation remained unchanged in relation to baseline values (0.72 +/- 0.03 vs 0.80 +/- 0.05). The V(T)8 and V(T)27 groups did not differ in terms of serum thiobarbituric acid reactive substances (3.97 +/- 0.27 vs 4.02 +/- 0.45 nmol/mL) or endothelial nitric oxide synthase expression (94.25 +/- 2.75 vs 96.25 +/- 2.39%). Our results show that glomerular filtration is acutely affected by high tidal volume ventilation but do not provide information about the mechanism.