Shock : molecular, cellular, and systemic pathobiological aspects and therapeutic approaches : the official journal the Shock Society, the European Shock Society, the Brazilian Shock Society, the International Federation of Shock Societies
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Comparative Study
Superoxide radical scavenging prevents cellular calcium dysregulation during intraabdominal sepsis.
The role of superoxide in sepsis-altered hepatocyte Ca2+i regulation was studied by examining the effect of treatment of septic rats with superoxide dismutase-polyethylene glycol (SOD-PEG) on hepatocyte Ca2+ influx and efflux, and cytosolic [Ca2+]. Rats were implanted with sterile or bacteria-laden (Escherichia coli and Bacteroides fragilis) fecal pellets into the abdominal cavity. Eight hours after the implantation, rats were treated with SOD-PEG or its vehicle PEG. ⋯ When challenged with vasopressin, the hepatocytes from septic rats, administered with PEG alone, did not elevate their [Ca2+]i as was characteristic of the hepatocytes from the nonseptic rats. The treatment of septic rats with SOD-PEG was effective in restoring Ca2+ influx, cellular exchangeable Ca2+, [Ca2+]i, and the [Ca2+]i response to vasopressin to levels found in the control and sterile groups. These findings support the concept that the generation of the superoxide free radical leads to Ca2+i-related derangements and related cell/organ dysfunction in sepsis.
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Small-volume resuscitation using hypertonic saline (7.5%) is effective for various types of shock. Recently, hypertonic saline has been proposed for fluid management in patients with impaired cardiovascular function. Whether hypertonic saline is safe in the compromised heart during coronary occlusion is not known. ⋯ Our data demonstrates variant effects of hypertonic saline on either normal or ischemic myocardium. Whereas contractile function and blood flow in the normal myocardium were improved after hypertonic saline infusion, further decreases in blood flow and contractile function in region distal to coronary occlusion could lead to worsening of ischemic injury. These data suggest that hypertonic saline may be deleterious in hearts with impaired contractile function caused by ischemia.
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Review Comparative Study
Beneficial versus detrimental effects of nitric oxide synthase inhibitors in circulatory shock: lessons learned from experimental and clinical studies.
Septic shock is a physiological derangement of the cardiovascular system characterized by pathological vasodilation. Recent studies have established a role for nitric oxide, previously known as endothelium-derived relaxing factor, in the vascular dysfunction of sepsis. ⋯ We provide here an overview of the preclinical studies of NOS inhibitors and an update of the clinical studies. The low toxicity and marked antihypotensive activity of NOS inhibitors in humans highlight some of the drawbacks of certain animal models and provide important insights into the experimental study of septic shock.
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Editorial Comment Review
Ca2+, a regulator of the inflammatory response--the good, the bad, and the possibilities.