Glutamine administration improves the prognosis of critically ill patients presumably by maintaining the physiologic intestinal barrier and by reducing the frequency of infections.

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The reduction of circulating neutrophil migration to infection sites is associated with a poor outcome of severe sepsis. ␣-1-Acid glycoprotein (AGP) was isolated from the sera of severely septic patients by HPLC and acrylamide gel electrophoresis and identified by mass spectrometry. Both the isolated protein and commercial AGP inhibited carrageenin-induced neutrophil migration into the rat peritoneal cavity when administered i.v. at a dose of 4.0 g per rat (95 pmol per rat). Analysis by intravital microscopy demonstrated that both proteins inhibited the rolling and adhesion of leukocytes in the mesenteric microcirculation. The inhibitory activity was blocked by 50 mg/kg aminoguanidine, s.c., and was not demonstrable in inducible nitric oxide synthase (iNOS) knockout mice. Incubation of AGP with neutrophils from healthy subjects induced the production of NO and inhibited the neutrophil chemotaxis by an iNOS/NO/cyclic guanosine 3,5-monophosphatedependent pathway. In addition, AGP induced the L-selectin shedding by neutrophils. The administration of AGP to rats with mild cecal ligation puncture sepsis inhibited neutrophil migration and reduced 7-day survival from Ϸ80% to 20%. These data demonstrate that AGP, an acute-phase protein, inhibits neutrophil migration by an NO-dependent process and suggest that AGP also participates in human sepsis.

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The transition from marine/brackish waters to freshwater habitats constitutes a severe osmotic and ionic challenge, and successful invasion has demanded the selection of morphological, physiological, biochemical and behavioral adaptations. We evaluated short-term (1 to 12 h exposure) and long-term (5 d acclimation), anisosmotic extracellular (osmolality, [Na + , Cl -]) and long-term isosmotic intracellular osmoregulatory capability in Palaemon northropi, a neotropical intertidal shrimp. P. northropi survives well and osmo-and ionoregulates strongly during short-and long-term exposure to 5-45 ‰ salinity, consistent with its rocky tide pool habitat subject to cyclic salinity fluctuations. Muscle total free amino acid (FAA) concentrations decreased by 63% in shrimp acclimated to 5 ‰ salinity, revealing a role in hypoosmotic cell volume regulation; this decrease is mainly a consequence of diminished glycine, arginine and proline. Total FAA contributed 31% to muscle intracellular osmolality at 20 ‰, an isosmotic salinity, and decreased to 13% after acclimation to 5 ‰. Gill and nerve tissue FAA concentrations remained unaltered. These tissue-specific responses reflect efficient anisosmotic and anisoionic extracellular regulatory mechanisms, and reveal the dependence of muscle tissue on intracellular osmotic effectors. FAA concentration is higher in P. northropi than in diadromous and hololimnetic palaemonids, confirming muscle FAA concentration as a good parameter to evaluate the degree of adaptation to dilute media. The osmoregulatory capability of P. northropi may reflect the potential physiological capacity of ancestral marine palaemonids to penetrate into dilute media, and reveals the importance of evaluating osmoregulatory processes in endeavors to comprehend the invasion of dilute media by ancestral marine crustaceans.