ATP from glycolysis is required for normal sodium homeostasis in resting fast-twitch rodent skeletal muscle.

Myocellular sodium homeostasis is commonly disrupted during critical illness for unknown reasons. Recent data suggest that changes in intracellular sodium content and the amount of ATP provided by glycolysis are closely related. The role of glycolysis and oxidative phosphorylation in providing fuel to the Na(+)-K(+) pump was investigated in resting rat extensor digitorum longus muscles incubated at 30 degrees C for 1 h. Oxidative inhibition with carbonyl cyanide m-chlorophenylhydrazone, known as CCCP (0.2 microM), or by hypooxygenation did not alter myocellular sodium or potassium content ([Na(+)](i), [K(+)](i), respectively), whereas treatment with iodoacetic acid (0.3 mM), which effectively blocked glycolysis, dramatically increased [Na(+)](i) and the [Na(+)](i)/[K(+)](i) ratio. Experiments using ouabain and measurements of myocellular high-energy phosphates indicate that Na(+)-K(+)-ATPase activity is only impaired when glycolysis is inhibited. The data suggest that normal glycolysis is required to regulate intracellular sodium in fast-twitch skeletal muscles, because it is the predominant source of the fuel for the Na(+)-K(+)-ATPase.

Effect of growth hormone on intestinal Na+/glucose cotransporter activity.

BACKGROUND: Growth hormone (GH) has been used alone or as part of a defined regimen in the treatment of patients with short bowel syndrome; however its mode of action remains unclear. Growth hormone has been shown to increase amino acid, water, and electrolyte absorption from the small intestine. The acute effect of growth hormone on intestinal sugar transport has not been described previously. METHODS: Mucosal preparations of rat jejunum were mounted in the Ussing chamber. Growth hormone (2 x 10(-6) M or 8 x 10(-6) M) or vehicle was added to the serosal chamber 1, 3, or 5 hours later. Twenty or 40 minutes after growth hormone addition, 30 mmol/L 3-O-methylglucose was added to both chambers, and the change in short-circuit current (deltaIsc) was recorded. In separate experiments, tissues were pretreated with phloridzin, an inhibitor of Na+/glucose cotransport, before the addition of 3-O-methylglucose. In the final set of experiments, kinetic studies were performed. RESULTS: GH did not induce any alterations in baseline electrical parameters. Only tissues left in the chambers for 5 hours, but not 1 or 3 hours, before GH treatment displayed a greater 3-O-methylglucose-induced deltaIsc than controls (p < .05). The increase in Isc induced by 3-O-methylglucose was 100% phloridzin-inhibitable. Kinetic analysis showed that growth hormone administration is associated with an increase in Na+/glucose cotransporter maximal velocity (Vmax) but no significant change in carrier affinity for substrate (Km). CONCLUSIONS: Growth hormone increases intestinal sugar transport, but only in tissue that has not been exposed to endogenous GH for over 3 hours.

In vitro complement activation favoring soluble C5b-9 complex formation alters myocellular sodium homeostasis.

BACKGROUND: Deranged Na(+) homeostasis in skeletal muscle is closely associated with excessive complement activation that is encountered during sepsis. Recent evidence suggests that soluble C5b-9 complexes (SC5b-9), which are readily detected in plasma during sepsis and have long been considered irrelevant nonmembrane binding end products of complement activation, may have numerous biologic effects. The purpose of this study, therefore, was to determine the effects of SC5b-9 on myocellular ion homeostasis and its mechanism(s) of action. METHODS: Hindlimb fast-twitch extensor digitorum longus (EDL) was freshly isolated from rats weighing 50 to 70 g and then incubated at 30 degrees C for 60 minutes in normal Krebs-Henseleit buffer (KHB, pH 7.4) containing 10% zymosan-activated rat serum (10 mg/mL at 37 degrees C for 60 minutes) as a source of SC5b-9. Zymosan particles were removed by centrifugation after activation to exclude any noncomplement direct effects. Heat-inactivated rat serum (56 degrees C for 30 minutes) was used as control. EDL muscle was also incubated with pertussis toxin (1 microg/mL), in Ca(2+)-free KHB, with thapsigargin (0.3 or 3 micromol/L), or with ouabain (0.01, 0.1 or 1 micromol/L) before and/or during incubation with 10% zymosan-activated or heat-inactivated rat serum. Intracellular Na(+) and K(+) contents ([Na(+)](i) or [K(+)](i)) of EDL muscle were determined by using flame photometry after washing in ice-cold Na(+)-free Tris-sucrose buffer. SC5b-9 in zymosan-activated human serum was determined by SC5b-9 enzyme-linked immunoassay. RESULTS: SC5b-9 in zymosan-activated human serum significantly increased by 400% as compared with nonactivated, normal human serum. Zymosan-activated rat serum markedly increased [Na+]i without affecting [K(+)](i) in fast-twitch EDL muscle, which was completely inhibited by pertussis toxin, removal of extracellular Ca(2+) or depletion of intracellular Ca(2+) with thapsigargin. The addition of ouabain (at micromolar concentrations) increased myocellular [Na(+)](i) and decreased myocellular [K(+)](i) in both the zymosan-activated and the heat-inactivated rat serum groups. The effects of ouabain on myocellular [Na(+)](i) and [K(+)](i) were equivalent in these 2 groups. Zymosan-activated and heat-inactivated rat serum had similar effects on myocellular [K(+)](i) in the presence or absence of pertussis toxin, removal of extracellular Ca(2+) or depletion of intracellular Ca(2+). CONCLUSIONS: Zymosan-activated rat serum (presumed SC5b-9 enriched) selectively alters Na(+) homeostasis in isolated fast-twitch skeletal muscle. The mechanisms for such effects may be linked to G-proteins, Ca(2+) flux and Na(+),K(+)-adenosine triphosphatase pump binding site blockade.

Sepsis increases the plasma membrane content of alpha1 and alpha2 isoforms of Na+-K+ adenosine triphosphatase in rat skeletal muscle.

HYPOTHESIS: Increased Na(+)-K(+) adenosine triphosphatase (ATPase) activity in skeletal muscle during sepsis is caused by transient increases in enzyme content within the plasma membrane. DESIGN: Randomized controlled study. SETTING: University laboratory. INTERVENTION: Eighty-eight adult male Wistar rats were randomly assigned to undergo cecal ligation and puncture (CLP) or sham operation. MAIN OUTCOME MEASURES: Gastrocnemius muscles were harvested 6, 12, 24, and 48 hours after operation and Na(+)-K(+) ATPase activities were measured spectrofluorimetrically. Messenger RNA (mRNA) levels for the alpha1 and alpha2 isoforms of Na(+)-K(+) ATPase were determined by Northern blot analysis. Crude membranes, internal membranes, and purified plasma membranes were isolated from gastrocnemius muscles and protein levels of alpha1 and alpha2 isoforms were determined by Western blot analysis. RESULTS: Na(+)-K(+) ATPase activity in the CLP group was significantly higher compared with the sham group 24 hours after operation (P<.05). However, there were no differences between the sham and CLP groups 6, 12, or 48 hours after operation. No significant differences between the CLP and sham groups were noted in mRNA levels for Na(+)-K(+) ATPase alpha1 and alpha2 isoforms. Western blot analysis revealed that the plasma membrane (but not internal membrane or crude membrane) content of alpha2 and alpha1 isoforms from the CLP group was significantly increased compared with the sham group 24 hours after operation (P<.05). CONCLUSIONS: Na(+)-K(+) ATPase activity increases 24 hours after CLP in gastrocnemius muscle and then declines. This increase is caused by increased Na(+)-K(+) ATPase protein levels in the plasma membrane.

Feeding critically ill patients: current concepts.

Provision of nutritional support to critically ill patients can be challenging. Critical care nurses must be aware of which patients require specific nutritional support, when to initiate nutritional support, and by which route to provide nutritional support. Consultation with a dietitian or nutritional support service can help facilitate this process. The key points in addressing these questions are (1) the nutritional status of the patient or the length of time he or she has been without significant nutrient intake, (2) whether the patient has a hypermetabolic condition that warrants the early use of nutritional support, and (3) the function of the patient's gastrointestinal tract. What to feed depends on the physiological state of the patient. Adjusting the nutrient composition of the feeding solution may prevent metabolic complications and may improve the overall outcome for the patient.

Sublytic complement attack increases intracellular sodium in rat skeletal muscle.

BACKGROUND: Although excessive complement activation and deranged sodium homeostasis in skeletal muscle are characteristic in sepsis, their relationship has not been examined. This study was designed to determine if sublytic complement activation can directly mediate changes in myocellular sodium content. MATERIALS AND METHODS: Fast-twitch extensor digitorum longus muscles were freshly isolated from infant rats. Unsensitized muscles were incubated at 30 degrees C for 60 min in the media containing 10% human or rat serum under conditions of no complement activation, activation by zymosan, inactivation by heat, C7 or C9 deficiency, selective inhibition of complement pathway, and inhibition of Na(+)-K(+) ATPase by ouabain. Intracellular sodium ([Na(+)](i)) and potassium ([K(+)](i)) contents of the muscles, myocellular ATP, and LDH release from the muscles were then determined. RESULTS: Normal human serum significantly increased [Na(+)](i) and the [Na(+)](i)/[K(+)](i) ratio in the muscles as well as zymosan-activated serum. Heat inactivation, C7 deficiency, and inhibition of the alternative pathway completely abolished the cationic changes. Average LDH release was identical in all groups and less than 6%. Complement activation did not impair ouabain-sensitive Na(+)-K(+) ATPase activity in the muscles or alter myocellular ATP. Thus, the observed alterations are not likely due to dysfunction of Na(+)-K(+) pump or depletion of myocellular energy. Instead, alterations in [Na(+)](i) were dependent upon the amount of C9 added to C9-deficient serum, which suggests that the alterations are likely dependent on transmembrane pores created by membrane attack complexes (MAC). CONCLUSIONS: Sublytic amounts of MAC formed as a result of complement activation can directly alter [Na(+)](i) in ex vivo skeletal muscle.

Glucagon-like peptide 2: a new treatment for chemotherapy-induced enteritis.

BACKGROUND: Glucagon-like peptide 2 (GLP-2) is a recently identified intestinal epithelium-specific growth factor that has been shown to reduce the severity of inflammatory disorders of the intestine in rodent models. We hypothesized that GLP-2 administration would be beneficial in chemotherapy-induced enteritis either by preventing injury or by promoting recovery. MATERIAL AND METHODS: Rats received no drug (control), chemotherapy alone [5-fluorouracil (5-FU), 190 mg/kg, ip] (Chemo), 5-FU followed by 3 days of GLP-2 analog (ALX-0600, 0.1 microg, sc twice daily) (CH-G), or GLP-2 analog for 6 days prior to 5-FU and for 3 days afterward (G-CH-G). Animals were pair fed. Rats received 5-bromo-2-deoxyuridine (Br-dU, 50 mg/kg, 2.5 h prior to sacrifice on Day 3 postchemotherapy) for immunohistochemical assessment of cellular proliferation. RESULTS: Chemotherapy induced significant reductions in body weight, villus height, and crypt depth compared with controls. Intestinal wet weight, villus height, and crypt depth were significantly higher for the CH-G group compared with the Chemo group. The CH-G group also showed a significant improvement in villus height compared with the G-CH-G group. Crypt depth, but not jejunal wet weight or villus height, was significantly improved in the G-CH-G group compared with the Chemo group. The percentage of Br-dU-labeled cells in the intestinal crypts did not differ among the groups. CONCLUSIONS: These results suggest, for the first time, that GLP-2 treatment initiated after chemotherapy administration enhances intestinal recovery. In contrast, GLP-2 treatment initiated prior to chemotherapy administration to prevent injury has less beneficial effect. GLP-2 administration may be beneficial to patients suffering from chemotherapy-induced enteritis.

Signaling mechanisms of glucagon-like peptide 2-induced intestinal epithelial cell proliferation.

BACKGROUND: Glucagon-like peptide 2 (GLP-2) stimulates intestinal epithelial growth with high potency and specificity. However, the intracellular signaling pathways responsible for the growth-stimulatory action of GLP-2 are not clearly understood. Here we report possible signaling pathways mediating GLP-2's proliferative actions in the human intestinal epithelial cell line Caco-2. MATERIALS AND METHODS: Caco-2 cells were subcultured under serum-deprived conditions in the presence or absence of GLP-2 (10 microM) and varying concentrations of inhibitors of three candidate kinases: genistein, a global tyrosine kinase inhibitor; LY294002, a phosphatidylinositide (PI) 3-kinase inhibitor; and PD 098059, a mitogen-activated/extracellular signal-regulated kinase (MEK) inhibitor. Proliferation was assessed using [(3)H]thymidine incorporation. Relative abundance of the phosphorylated forms of two specific mitogen-activated protein kinases (MAPKs), ERK1 and ERK2, was assessed by Western blotting. RESULTS: GLP-2-treated cells demonstrated a greater than 10-fold increase in proliferation. This response was inhibited by genistein, LY294002, and PD 098059 in a dose-dependent fashion. A significantly greater abundance of the phosphorylated forms of both ERK-1 and ERK-2 was present in cells within 5 min of treatment with GLP-2. CONCLUSIONS: GLP-2 stimulates the proliferation of Caco-2 cells in vitro. This increase in Caco-2 proliferation in response to GLP-2 may be due, at least in part, to the involvement of both the PI 3-kinase and the MAPK pathways.

Metabolic assessment.

Although no techniques are currently available that meet the needs of nutrition-support professionals, the future is promising. This article reviews various methods and techniques used to assess the metabolic and nutritional status of surgical patients. Technologic advances in bioengineering, molecular biology, and physiology are providing exciting new tools that may eventually replace or supplement traditional static indices of metabolic assessment. At the very least, an increased understanding of the cellular abnormalities associated with various diseases will likely change our view of illness and our approaches to nutritional and metabolic intervention.

Hindlimb ischemia-reperfusion increases complement deposition and glycolysis.

BACKGROUND: Hindlimb ischemia-reperfusion (HIR) impairs cellular energy metabolism and causes local muscle injury possibly through free radical or complement-mediated mechanisms. MATERIALS AND METHODS: To determine the relationship among myocellular energetics, histopathological injury, and mediator activity, male Wistar rats underwent 4 h of Sham (n = 8), Unilateral (n = 8), or Bilateral (n = 8) hindlimb ischemia followed by 4 h of reperfusion. All rats underwent 31P magnetic resonance spectroscopy of their right gastrocnemius muscle to determine various high-energy phosphate ratios including ATP to Pi (ATP/Pi, a measure of energy status) and phosphocreatine to Pi (PCr/Pi, a measure of thermodynamic capacity). Gastrocnemius muscles were then harvested to determine muscle damage and complement membrane attack complex (MAC) deposition by immunohistochemical staining [grade 0 (none) to 3 (very severe)] and to measure glutathione (GSH), DNA, and enzyme activities: beta-hydroxyacyl-CoA dehydrogenase, phosphofructokinase, and citrate synthetase. RESULTS: HIR was associated with significant declines in ATP/Pi and PCr/Pi (P < 0.001). Progressively more severe HIR (Sham, Unilateral, Bilateral) was associated with greater MAC deposition (0. 0 +/- 0.0, 1.0 +/- 0.3, 1.5 +/- 0.4, P = 0.06, mean +/- SEM) and histological damage (0.0 +/- 0.0, 0.9 +/- 0.3, 1.3 +/- 0.4, P < 0. 05). GSH levels, beta-hydroxyacyl-CoA dehydrogenase, and citrate synthetase activities were not affected by HIR, but phosphofructokinase activity increased (24.09 +/- 2.42, 35.16 +/- 5. 26, 59.29 +/- 9.82 mmol/mg of DNA/min, P < 0.05). Although GSH levels were not significantly altered, complement deposition was closely associated with skeletal muscle injury and compensatory changes in glycolysis. Alterations in myocellular bioenergetics after HIR closely paralleled complement deposition rather than GSH depletion. CONCLUSIONS: Therapeutic strategies aimed at controlling complement activity and assessment techniques based on bioenergetics may allow more precise determinations of the effects of HIR injury.

Metabolic and monetary costs of avoidable parenteral nutrition use.

BACKGROUND: We prospectively collected data on in patients receiving parenteral nutrition to determine the magnitude of potentially preventable metabolic and monetary costs associated with parenteral nutrition. METHODS: Parenteral nutrition was prescribed by the treating physicians with optional consultation from a multidisciplinary metabolic support service. Days on parenteral nutrition, appropriateness of parenteral nutrition, metabolic complications, and avoidable parenteral nutrition charges were determined. Parenteral nutrition use was considered "indicated" or "not indicated" based on the American Society for Parenteral and Enteral Nutrition guidelines and "preventable" if the gastrointestinal tract was functional but not accessed when possible. RESULTS: Of the 209 parenteral nutrition starts, 62% were indicated, 23% were preventable, and 15% were not indicated. Parenteral nutrition starts were deemed indicated in 82% of instances in which a metabolic support service consult was obtained, compared with 56% in which a consultation was not obtained (p = .004). Hyperglycemia was the most common metabolic complication, with an overall incidence of 20%. Metabolic complications occurred less frequently in patients who received a metabolic support service consultation compared with patients who did not (34% vs 66% of parenteral nutrition days, respectively; p = .004). Parenteral nutrition use of < or =5 days duration was significantly less frequent among patients who received metabolic support service consultation (16% vs 35%; p = .002). Parenteral nutrition that was not indicated or preventable resulted in excess annualized patient charges of more than one half million dollars not accounting for charges related to treatment of potentially avoidable parenteral nutrition complications. CONCLUSIONS: This study illustrates that not-indicated and preventable parenteral nutrition initiation, short-term parenteral nutrition use, and metabolic complications are less likely when patients receive consultation by a multidisciplinary team with expertise in nutrition and metabolic support. Furthermore, the avoidance of inappropriate parenteral nutrition use translates into substantial cost savings.

Skeletal muscle phosphocreatine depletion depresses myocellular energy status during sepsis.

OBJECTIVE: To determine the effects of phosphocreatine (PCr) depletion on myocellular energetics. DESIGN: Randomized controlled study. SETTING: University laboratory. MATERIALS: Thirty-eight adult male Wistar rats (110-121 g). METHODS: The poorly metabolized creatine analogue beta-guanidinopropionic acid, (beta-GPA, 2% of a gel diet) was fed to the rats for 14 days to replace (75%) endogenous PCr stores before cecal ligation and puncture (CLP). Rats were randomized to receive sham operation and gel diet (sham-gel group [n=10]), sham operation and beta-GPA diet (sham-beta-GPA group [n=9]), CLP and gel diet (CLP-gel group [n=10]), and CLP and beta-GPA diet (CLP-beta-GPA group [n=9]). On day 14, all animals underwent operation. Twenty-four hours later, in vivo phosphorus 31-labeled magnetic resonance spectroscopy (31P-MRS) of the gastrocnemius muscle was performed. Muscle samples were collected to determine enzyme activities of beta-hydroxyacyl-CoA dehydrogenase, phosphofructokinase, citrate synthase, and the metabolites adenosine triphosphate (ATP), PCr, inorganic phosphate, and creatine. Free adenosine diphosphate levels, the phosphorylation potential, and free energy change of ATP hydrolysis were then calculated. RESULTS: All animals undergoing CLP but no controls had positive results of blood cultures. Although sham-beta-GPA animals had altered bioenergetics, CLP-beta-GPA rats experienced a greater deterioration of energy state compared with CLP-gel controls. Glycolytic and oxidative enzyme activities were not significantly different between groups and therefore could not explain the observed differences. CONCLUSIONS: There is an overall decrease in energy availability during sepsis, which is worsened by PCr depletion. These changes support the contention that PCr plays an important role as an ATP buffer during systemic infection.

Superiority of blood over saline resuscitation from hemorrhagic shock: a 31P magnetic resonance spectroscopy study.

OBJECTIVE: To study the relation between blood and saline administration, postresuscitation hematocrit (Hct) level, and metabolic recovery after hemorrhagic shock. SUMMARY BACKGROUND DATA: It is generally believed that crystalloid can be substituted, in whole or in part, for blood during resuscitation of hemorrhagic shock. This is based on the belief that Hct can be safely reduced but should not fall below a critical level. METHODS: Male rats weighing 200 g were subjected to an isobaric hemorrhagic shock at a mean arterial pressure of 30 mmHg for 14 minutes, after which they were randomized to one of three resuscitation regimens. Control group (n = 36) were resuscitated by return of all shed blood. Mid-Hct (n = 39) and low-Hct (n = 60) groups were depleted of one third and one half of their circulating blood volumes, respectively, and were resuscitated with three times that volume of normal saline. Skeletal muscle intracellular energetics and pH were measured serially using 31P magnetic resonance spectroscopy at baseline, during shock, and after resuscitation. Arterial blood was sampled at the same time points. The number of surviving animals in each group at 24 hours was recorded. RESULTS: After resuscitation, surviving rats in the low-Hct group demonstrated a greater consumption of high-energy phosphocreatine stores than did the other groups (control = 0.479 +/- 0.003, mid-Hct = 0.465 +/- 0.004, low-Hct = 0.457 +/- 0.007, mean +/- standard error of the mean; p < 0.01 low-Hct vs. other groups by analysis of variance). The rats that received saline resuscitation developed a relative intracellular acidosis (control = 7.29 +/- 0.02, mid-Hct = 7.25 +/- 0.02, low-Hct = 7.23 +/- 0.02; p < 0.05 controls vs. other groups by analysis of variance). At 24 hours, the death rates were significantly different among the groups: control = 1 of 36 rats (2.8%), mid-Hct = 6 of 39 (15.4%), and low-Hct = 14 of 60 (23.3%) (p < 0.05 by chi square analysis). CONCLUSION: The oxygen-carrying capacity of resuscitation fluid has an important impact on intracellular metabolism and outcome.

Starvation enhances hepatic free radical release following endotoxemia.

Although it is well known that malnourished patients who become septic have an increased risk of organ failure and death compared to normally nourished individuals, the pathological processe(s) underlying this observation are unknown. To evaluate one possible explanation for this finding, we tested the hypothesis that malnutrition depresses hepatic antioxidant stores and accelerates hepatic release of oxygen free radicals in an animal model of sepsis. Male rats were either fasted (n = 14) or fed (n = 14) for 3 days prior to receiving lipopolysaccharide (LPS, 17 mg/kg intraperitoneally). Animals were weighed daily and then sacrificed 6 and 24 hr after LPS administration to determine hepatic superoxide anion (an oxygen free radical) release and liver glutathione (GSH, an antioxidant) content. Fasted rats were severely malnourished as indicated by a 23% decrease in body weight compared to fed rats, which gained 11% (P < 0.05). Liver GSH was depressed by 30% (P < 0.05) and 20% (P = 0.066) in the fasted compared to fed animals 6 and 24 hr after LPS administration. In addition, hepatic superoxide anion release was 210 and 75% higher in the fasted animals 6 and 24 hr after LPS injection (P < 0.05 at both time points). Liver superoxide anion release and GSH content were negatively correlated (P < 0.001, R = - 0.73) indicating that superoxide anion release increased as GSH content fell. Malnutrition leads to depletion of liver antioxidant stores with accelerated release of hepatic oxygen free radicals. Oxidant-mediated organ damage may be one cause of increased morbidity and mortality in malnourished, systemically infected patients.

Glucocorticoid receptor antagonism by mifepristone alters phosphocreatine breakdown during sepsis.

OBJECTIVE: To determine the role of glucocorticoids in the regulation of myocellular energetics induced by sepsis by means of the glucocorticoid receptor antagonist mifepristone (RU 38486). DESIGN: Randomized controlled study. SETTING: University laboratories. PARTICIPANTS: Thirty-two adult male Wistar rats. METHODS: Animals were randomly assigned to 1 of 4 groups. In 2 groups, mifepristone (10 mg/kg) was administered by gavage feeding 2 hours before cecal ligation and single 18-gauge needle puncture or sham operation. The other 2 groups of animals received placebo gavage feedings 2 hours before their surgical procedures. Twenty-four hours after operation, high-energy phosphate ratios, intracellular pH, the forward rate constant for the creatine kinase reaction, and phosphocreatine breakdown rates were measured in the gastrocnemius muscle by in vivo phosphorus 31 magnetic resonance spectroscopy. Tissue and blood samples were collected to measure creatine and adenosine 5'-triphosphate concentrations, Na(+)-K+ adenosine triphosphatase activity, and circulating corticosterone levels. RESULTS: Circulating corticosterone levels were twice as high in septic animals as in sham-operation control rats (P < .01). Phosphocreatine breakdown rates and Na(+)-K+ adenosine triphosphatase activity were significantly higher (40% and 75%, respectively; P < .01) in placebo-treated septic rats than in sham-operation control rats. However, phosphocreatine breakdown rates and Na(+)-K+ adenosine triphosphatase activity in mifepristone-treated septic animals were not significantly elevated above control levels. CONCLUSION: Pretreatment with mifepristone reduces the demand for adenosine triphosphate production from phosphocreatine breakdown and downregulates Na(+)-K+ adenosine triphosphatase activity during sepsis.

Use of bioelectrical impedance analysis measurements in the clinical management of critical illness.

I review the utility of bioelectrical impedance analysis (BIA) for assessing changes in body composition and content and distribution of body water in critically ill patients. Published studies suggest that resistance measurements provide a reasonable estimate of total body water but that the precision of the measurements is poor. Presently, BIA does not appear to be a useful clinical technique for measuring changes in body composition. Despite the limitations of current technology, the utility and efficacy of BIA merit evaluation in large, longitudinal studies if our understanding of the meaning of changes in the electrical properties of the body is to improve.