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Signal transduction through the surface molecule CD40 is critical for cellular activation in immunoinflammatory states such as sepsis. The mechanisms regulating this pathway are not completely understood. Because CD40 displays potentially regulatory cysteine residues and CD40 is probably exposed to NO in the inflammatory milieu, we hypothesized that S-nitrosylation, the interaction of NO with cysteines residues, acts as a post-translational modification on CD40, coregulating the signaling activity and, therefore, the level of cellular activation. As assessed by the biotin switch and the reduction/chemiluminescence S-nitrosylation detection techniques, CD40 was found to be S-nitrosylated endogenously and upon exposure to NO donors in both human and murine macrophages. S-nitrosylation of CD40 was associated with milder activation by its ligand (CD40L), leading to reduced in vitro cytokine (IL-1beta, IL-12, and TNF-alpha) production, which was reversed in the presence of inhibitors of NO synthesis. S-nitrosylated CD40 was found in resting RAW 246.7 macrophages and BALB/c mice peritoneal macrophages, turning into the denitrosylated state upon in vitro or systemic exposure, respectively, to LPS. Moreover, monocytes from patients with sepsis displayed denitrosylated CD40 in contrast to the CD40 S-nitrosylation measured in healthy individuals. Finally, in an attempt to explain how S-nitrosylation regulates CD40 activation, we demonstrate that NO affects the redistribution of CD40 on the cell surface, which is a requirement for optimal signal transduction. Our results support a novel post-translational regulatory mechanism in which the CD40 signal may be, at least in part, dependent on cellular activation-induced receptor denitrosylation.

Objectives: Acute pancreatitis (AP) protease release induces lung parenchymal destruction via matrix metalloproteinases (MMPs), a neutrophil (polymorphonuclear leukocyte)-dependent process. Recent studies in hemorrhagic shock revealed that hypertonic saline (HTS) has an anti-inflammatory effect and can inhibit a variety of neutrophil functions. The aim of this study was to determine whether HTS and its actions in the pathway of neutrophil migration, MMPs, and heat shock proteins (HSPs) are effective in protecting the lung from injury associated with AP. Methods: We determined neutrophil infiltration and expressions of MMPs and HSPs in the lung tissue after AP induced by retrograde infusion of 2.5% of sodium taurocholate. Results: Animals submitted to AP that received HTS compared with those who received normal saline presented with increased HSP70 and HSP90 expressions and reduced myeloperoxidase levels and MMP-9 expression and activity. Conclusions: Our data raised the hypothesis that a sequence of HTS lung protection events increases HSP70 and HSP90, inhibiting infiltration of neutrophils and their protease actions in the lung.

Hypertonic saline solution (HS solution, NaCl 7.5%) has shown to restore hemodynamic parameters in hemorrhagic shock and to decrease the inflammation triggered by ischemia-reperfusion injury (I-R). Therefore, our objective was to investigate the effects of HS solution on the mechanisms involved in I-R, in an experimental model of controlled hemorrhagic shock. Wistar rats (280-350 g) were submitted to controlled bleeding, keeping the mean arterial pressure around 40 mmHg, for 1 h. After that, rats were randomized and treated with HS solution (4 mL/kg) or normal saline (34 mL/kg). There were no differences in hemodynamic parameters between both groups for at least 2 h after shock. No difference either was observed in reactive oxygen species generation (measured indirectly by malondialdehyde concentration) or cytokines (interleukins 6 and 10) production (measured by enzyme-linked immunosorbent assay). Quantitative analysis of lung tissue showed a smaller neutrophil infiltration in animals that received HS solution. Moreover, the animals in the HS group showed an increased expression of heat shock protein 70. Therefore, we concluded that treatment of hemorrhagic shock with HS solution can decrease pulmonary inflammation and increase cellular protection by up-regulating heat shock protein 70 expression.

A matched case-control study was carried out at a Brazilian academic medical emergency department to identify the occurrence of adverse events (AEs) in patients with community- acquired pneumonia (CAP) and disclose their association with in- hospital death. The cases comprised 101 consecutive deaths and the controls 101 discharged patients admitted for CAP from March 1996 to September 1999. Adverse events were classified according to severity, potential causes, the occurrence of nosocomial in- fections, and the related professional category. A total of 603 AEs were identified, predominating among the deceased patients: 456 events (75.6%) in 85 cases and 147 (24.4%) in 55 controls. Severe AEs also predominated among the cases. Procedures and nursing activities were the main AE-related potential causes. The oc- currence of at least 1 AE was associated with a higher risk of death (3.25-fold). This association was stronger when either severe AEs (8.37-fold) or medical AEs (4.23-fold) were analyzed. (Infect Dis Clin Pract 2006;14:350- 359)

Severe acute pancreatitis (AP) is characterized by hemodynamic alterations and a systemic inflammatory response, leading to a high mortality rate. Treatment of hemorrhagic shock with hypertonic saline solutions significantly reduces mortality through an improvement in the hemodynamic conditions and possibly by an anti-inflammatory effect. Therefore, hypertonic solutions could be effective in AP.Wistar rats were divided in 4 groups: group C, control, without AP; group NT, AP, without treatment; group NS, treatment with normal saline solution (NaCl 0.9%) 1 hour after AP; group HTS, treatment with hypertonic saline solution (NaCl 7.5%) 1 hour after AP. AP was induced by injection of 2.5% sodium taurocholate into the pancreatic duct. Mean arterial blood pressure (MAP) and heart rate were recorded at 0 and 2, 4, 24, and 48 hours after AP. After induction of AP, animals were killed at 2, 12, 24, and 48 hours for serum amylase, interleukin (IL)-6, and IL-10 analysis, pancreatic tissue culture and histologic analysis, oxidation and phosphorylation of liver mitochondria, pulmonary myeloperoxidase activity (MPO), and mortality study.In animals of groups NS and NT, a significant decrease of MAP was observed 48 hours after AP (NS: 91 +/- 3 mm Hg; NT: 89 +/- 3 mm Hg) compared with baseline (C: 105 +/- 2 mm Hg) and to HTS group (HTS: 102 +/- 2 mm Hg; P0.05). In animals of group NT, NS, and HTS, serum IL-6 and IL-10 levels were significantly higher at 2 hours after AP compared with the control group. However, IL-6 levels at 12 hours after AP and IL-10 levels at 2 and 12 hours after AP were significant lower in group HTS compared with NS and NT groups (P0.05). In group HTS, a decrease of pulmonary MPO activity and of pancreatic infection was observed 24 hours after AP compared with NT and NS groups (P0.05). A significant reduction on pancreatic acinar necrosis and mitochondrial dysfunction was observed after 48 hours of AP in animals of group HTS compared with groups NT and NS (P0.05). A significant reduction on mortality was observed in HTS (0/14) compared with NS (6/17; 35%) and NT (7/20; 35%).The administration of hypertonic saline solution in experimental AP attenuated hemodynamic alterations, decreased inflammatory cytokines, diminished systemic lesions and pancreatic acinar necrosis, prevented pancreatic infection, and reduced the mortality rate.

Hypertonic saline, or saline-dextran resuscitation is normally achieved with an Na+ load of 4.8 to 7.2 mEq/kg given in a small volume (typically 4 to 6 ml/kg NaCl 7.5%). Na+ can also be administered saturated in a smaller volume, e.g., 1 to 1.5 ml/kg NaCl 25%, with similar results. Such reduction in administered volume would be an asset in prehospital trauma management. In the present experiments, severely bled (45 ml/kg) dogs were treated with one of three NaCl/dextran-70 solutions: S1, 25% NaCl + 24% dextran (1.5 ml/kg); S2, 15% NaCl + 14.4% dextran (2.5 ml/kg); S3, 7.5% NaCl + 6% dextran (5 ml/kg). S1, S2, and S3 were pump-infused in 10 min into a peripheral vein; S1 and S2 were also given into the right atrium. S1, S2, or S3 produced a number of similar responses irrespective of the route of administration; arterial pressure, cardiac index, and base excess reverted to near control levels, plasma Na+ was raised to 155-158 mEq/L, and 5-day survival was high and comparable. Plasma volume, and total and mean red cell volumes were similarly affected in all groups; however, peripheral injections of S1 and S2 induced severe hemolysis (plasma Hgb: 53 +/- 6 and 34 +/- 4 mg/dl, respectively), while right atrial S1 and S2 caused mild hemolysis (22 +/- 3 and 14 +/- 3 mg/dl, respectively). In contrast, S3 never induced hemolysis.(ABSTRACT TRUNCATED AT 250 WORDS)