Anesthesiology
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Mechanisms of sevoflurane-induced myocardial preconditioning in isolated human right atria in vitro.
The authors examined the role of adenosine triphosphate-sensitive potassium channels and adenosine A(1) receptors in sevoflurane-induced preconditioning on isolated human myocardium. ⋯ In vitro, sevoflurane preconditions human myocardium against hypoxia through activation of adenosine triphosphate-sensitive potassium channels and stimulation of adenosine A(1) receptors.
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The safety of chronically administered intrathecal morphine has been questioned. Therefore, the authors examined the behavioral and neurologic effects and neurotoxicity of continuous intrathecal morphine administration in sheep. ⋯ The toxicity of intrathecal morphine seems to be dependent on the amount of morphine infused, although the effects of dose versus concentration cannot be clearly distinguished in this study. Intrathecal morphine doses of 12- 18 mg/day produced inflammatory masses extending from the catheter tip down the length of the catheter within the subarachnoid space. Doses of 6-9 mg/day produced mild-to-moderate inflammation 5 cm cranial to the catheter tip. A dose of 3 mg/day produced no neurotoxicity and spinal histopathologic changes that were equivalent to those observed in the saline-treated animals.
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Comparative Study
Protection with antibody to tumor necrosis factor differs with similarly lethal Escherichia coli versus Staphylococcus aureus pneumonia in rats.
Differing factors may alter the effects of antibody to tumor necrosis factor (TNF) in infection and sepsis. The authors tested whether bacteria type or treatment route alters antibody to TNF in a rat model of bacterial pneumonia. ⋯ Antibody to TNF improved host defense and survival rates with both lethal E. coli and S. aureus pneumonia, but protection was greater with E. coli, where TNF concentrations were higher than with S. aureus. The efficacy of antiinflammatory agents in sepsis may be altered by bacteria type.
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It has been suggested that the dose of intravenous morphine used during postoperative titration is not modified by aging. The authors therefore studied morphine requirements in patients undergoing total hip replacement. ⋯ The dose of intravenous morphine during titration is not modified in elderly patients, in contrast to the dose administered subcutaneously over a prolonged period.
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Despite the extensive use of intrathecal morphine infusion for pain, no systematic safety studies exist on its effects in high concentrations. The authors assessed the effects of morphine and clonidine given 28 days intrathecally in dogs. ⋯ The authors found that high intrathecal morphine concentrations lead to aseptic intrathecal inflammatory masses. The lack of effect of clonidine and the possible suppressive effects of clonidine on the local reaction suggest the utility of such coadministration.