Articles: sepsis.
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Critical care medicine · Mar 1994
Hematocrit modifies the circulatory control of systemic and myocardial oxygen utilization in septic sheep.
To describe the relationship between hematocrit and oxygen utilization before and after the onset of a hyperdynamic septic state. ⋯ The normal circulatory compensation to anemia in hyperdynamic sepsis includes increases in cardiac index and whole-body oxygen extraction, although greater reliance is likely placed on the use of systemic flow reserve to maintain tissue oxygen uptake in septic vs. healthy study conditions. Furthermore, increased reliance on myocardial oxygen extraction in sepsis suggests that the normal flow-reserve supporting myocardial oxygen availability may be limited in this syndrome.
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This study assessed the hepatic acute phase response and cellular Ca2+ regulation in septic animals and in hepatoma cell lines in vitro. Sepsis was induced in male Sprague-Dawley rats by implanting in their abdominal cavities fecal pellets impregnated with live Escherichia coli and Bacteroides fragilis. 8 h after implantations, rats were treated with diltiazem (1.2 mg/kg) or superoxide dismutase (SOD) (5 x 10(3) units/kg). After 24 h, plasma acute phase proteins (APP) were determined by immunoelectrophoresis, and hepatic APP-mRNAs by Northern blot hybridization. ⋯ Because diltiazem was previously shown to prevent sepsis-related disturbances in hepatic cellular Ca2+ regulation, its mediation of decrease in APP, systemic/metabolic response, and mortality may be effected through modifications in cellular Ca2+ regulation. The data from hepatoma cells show an attenuation of the AAP can result from direct effects of a calcium blocker. However, whether the blocker primarily modifies cellular Ca2+ regulation and secondarily effects APP gene expression, or directly effects gene expression remains unknown.
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The proteolytic enzyme elastase released by granulocytes (polymorphonuclear leukocytes [PMN]) in high concentrations during sepsis causes degradation of essential plasma proteins, endothelial damage, and tissue edema. This may result in organ dysfunction and organ failure during sepsis, since increased elastase plasma levels correlate with the mortality rate of patients with sepsis. In vitro studies demonstrated a regulatory role of inflammatory cytokines (tumor necrosis factor-alpha [TNF-alpha], interleukin 1 beta [IL-1 beta], IL-8]) upregulating protease release by PMN. In this light, the interactions between cytokine release by macrophages and altered elastase secretion during sepsis remain to be determined. ⋯ These data indicate an increased release of elastase by PMN despite a reduced secretion of PMN-activating cytokines. Although priming effects of TNF-alpha, IL-1 beta, and IL-8 on protease secretion in vivo cannot be excluded completely, other mediators or mechanisms may be involved in the upregulation of detrimental protease release during sepsis.