The transcription factors NF-kappab and AP-1 are differentially regulated in skeletal muscle during sepsis

Sepsis is associated with increased muscle proteolysis and upregulated transcription of several genes in the ubiquitin-proteasome proteolytic pathway. Glucocorticoids are the most important mediator of sepsis-induced muscle cachexia. Here, we examined the influence of sepsis in rats on the transcription factors NF-kappaB and AP-1 in skeletal muscle and the potential role of glucocorticoids in the regulation of these transcription factors. Sepsis was induced by cecal ligation and puncture (CLP). Control rats were sham-operated. NF-kappaB and AP-1 DNA binding activity was determined by electrophoretic mobility shift assay (EMSA) in extensor digitorum longus muscles at different time points up to 16 h after sham-operation or CLP. Sepsis resulted in an early (4 h) upregulation of NF-kappaB activity followed by inhibited NF-kappaB activity at 16 h. AP-1 binding activity was increased at all time points studied during the septic course. When rats were treated with the glucocorticoid receptor antagonist RU38486, NF-kappaB activity increased, whereas AP-1 activity was not influenced by RU38486. The results suggest that NF-kappaB and AP-1 are differentially regulated in skeletal muscle during sepsis and that glucocorticoids may regulate some but not all transcription factors in septic muscle.

Dantrolene reduces serum TNFalpha and corticosterone levels and muscle calcium, calpain gene expression, and protein breakdown in septic rats

The effects of dantrolene on serum TNFalpha and corticosterone levels and on muscle calcium, calpain gene expression, and protein breakdown were studied in rats with abdominal sepsis induced by cecal ligation and puncture. Treatment of rats with 10 mg/kg of dantrolene 2 h before and 8 h after induction of sepsis reduced serum TNFalpha and corticosterone, muscle calcium levels, mRNA levels for m- and mu-calpain, and the muscle specific calpain p94, as well as total and myofibrillar protein breakdown rates, determined as release of tyrosine and 3-methylhistidine, respectively, from incubated extensor digitorum longus muscles. The results support the concept that increased calcium concentrations may be an important mechanism of sepsis-induced muscle protein breakdown. The data also indicate that other mechanisms, in addition to reduced muscle calcium concentrations such as decreased levels of TNFalpha and glucocorticoids, may contribute to the anti-catabolic effects of dantrolene during sepsis. The observations are important from a clinical standpoint because they suggest that the catabolic response in skeletal muscle during sepsis may be prevented by treatment with a calcium antagonist.

Muscle cachexia: current concepts of intracellular mechanisms and molecular regulation

OBJECTIVE

To review present knowledge of intracellular mechanisms and molecular regulation of muscle cachexia.

SUMMARY BACKGROUND DATA

Muscle cachexia, mainly reflecting degradation of myofibrillar proteins, is an important clinical feature in patients with severe injury, sepsis, and cancer. The catabolic response in skeletal muscle may result in muscle wasting and weakness, delaying or preventing ambulation and rehabilitation in these patients and increasing the risk for pulmonary complications.

RESULTS

Muscle cachexia, induced by severe injury, sepsis, and cancer, is associated with increased gene expression and activity of the calcium/calpain- and ubiquitin/proteasome-proteolytic pathways. Calcium/calpain-regulated release of myofilaments from the sarcomere is an early, and perhaps rate-limiting, component of the catabolic response in muscle. Released myofilaments are ubiquitinated in the N-end rule pathway, regulated by the ubiquitin-conjugating enzyme E2(14k) and the ubiquitin ligase E3 alpha, and degraded by the 26S proteasome.

CONCLUSIONS

An understanding of the mechanisms regulating muscle protein breakdown is important for the development of therapeutic strategies aimed at treating or preventing muscle cachexia in patients with severe injury, sepsis, cancer, and perhaps other catabolic conditions as well.

Infusion pump performance with vertical displacement: effect of syringe pump and assembly type

OBJECTIVE

To evaluate the effect of different infusion pump models on continuity of drug delivery during vertical displacement of syringe pumps.

DESIGN

Zero-drug delivery time (ZDDT), retrograde aspiration volume, and infusion bolus were recorded using the same syringe in three different models of syringe pump after lowering and elevating the pump. Compliance of each infusion assembly was measured using the occlusion release technique at 38 mmHg.

RESULTS

Lowering the pump by 50 cm at an infusion rate of 1 ml/h resulted in ZDDT values ranging from 2.78 +/- 0.29 to 5.99 +/- 1.09 min. Elevating the syringe pump to its original position caused infusion boluses between 44.1 +/- 3.2 and 77.1 +/- 5.1 microl. The results demonstrated that there are large differences between syringe pump models (F = 66.8, df = 2/33, p < 0.0001) and between pumps of the same model (F = 21.3, df = 1/34, p < 0.0001). A similar pattern was found in retrograde aspiration volume and infusion bolus.

CONCLUSION

All tested pumps led to clinically relevant flow irregularities during vertical displacement of the syringe pump. Thus, vertical displacement of any syringe pump connected to an infusion line delivering highly potent drugs at low infusion rates should be avoided. The variability across syringe pumps indicates that syringe pump design remains an area of potential further improvement for reducing the risk of adverse patient events.

Phonon density of states of single-wall carbon nanotubes

The vibrational density of states of single-wall carbon nanotubes (SWNT) was obtained from inelastic neutron scattering data from 0 to 225 meV. The spectrum is similar to that of graphite above 40 meV, while intratube features are clearly observed at 22 and 36 meV. An unusual energy dependence below 10 meV is assigned to contributions from intertube modes in the 2D triangular lattice of SWNT bundles, and from intertube coupling to intratube excitations. Good agreement between experiment and a calculated density of states for the SWNT lattice is found over the entire energy range.

[Rational utilization of antibiotics in critically ill children]

BACKGROUND

The high risks associated with untreated infection in critically ill newborns or children lower the threshold for prescription of antibiotic treatment. Inappropriate use of antibiotic therapy promotes the emergence of resistant strains. This study had three aims: to identify sources of inappropriate antibiotic utilisation, to develop revised guidelines and to implement changes.

METHODS

An observational study was performed in a tertiary, multidisciplinary, neonatal and paediatric intensive care unit (PICU) of a university teaching hospital during a 7-month period (456 admissions). Guidelines addressing one of the identified sources of inappropriate utilisation (prophylaxis following surgery) were developed according to published evidence and implemented, and the effect on prescription patterns was assessed during a second observation period.

RESULTS

Patients received systemic antibiotics during 54.6% of all hospitalisation days. Antibiotics prescribed for suspected or proven infection were often continued 1-2 days beyond the intended duration. Prophylaxis accounted for 28% of all systemic antibiotics given, and postsurgical prophylaxis accounted for 14.6% of all exposure days. The literature search revealed little evidence to support this practice. After new guidelines were introduced with the aim of restricting surgical prophylaxis to a single dose prior to surgery, the rate of postsurgical prophylaxis dropped from 14.6 to 11.2% of all exposure days, accompanied by a significant decline in the overall exposure rate from 54.6 to 50.2% of all hospitalisation days.

CONCLUSION

Several sources of inappropriate antibiotic utilisation were identified. These include failure to discontinue treatment and prolonged prophylaxis after surgery. Implementation of new guidelines reduced antibiotic utilisation.

Pertussis toxin sensitization alters the pathogenesis of subsequent respiratory syncytial virus infection

Evidence suggests that both host and viral factors influence disease severity after infection with respiratory syncytial virus (RSV). To characterize the effects of pertussis toxin (PT) sensitization on subsequent RSV infection, BALB/c mice were treated with PT parenterally before RSV challenge. Priming with purified and detoxified PT before RSV challenge increased postchallenge weight loss and mortality. PT priming changed the kinetics, location, and composition of the cellular infiltrate in the lung but altered neither antibody responses nor virus titers. Passive transfer of PT-sensitized splenocytes produced similar responses. Priming with purified, but not genetically detoxified, PT propagated a modest type 2 cytokine response to RSV antigens. However, anti-interleukin-4 treatment before RSV challenge failed to abrogate the effects of PT priming. These data confirm that the preexisting immune environment can change virus-specific immunity and provide both a model for study of RSV disease and evidence that noninfectious immunomodulators may impact pathogen-specific immunity.

Quantized phonon spectrum of single-wall carbon nanotubes

The electronic spectra of carbon nanotubes and other nanoscale systems are quantized because of their small radii. Similar quantization in the phonon spectra has been difficult to observe because of the far smaller energy scale. We probed this regime by measuring the temperature-dependent specific heat of purified single-wall nanotubes. The data show direct evidence of one-dimensional quantized phonon subbands. Above 4 kelvin, they are in excellent agreement with model calculations of individual nanotubes and differ markedly from the specific heat of two-dimensional graphene or three-dimensional graphite. Detailed modeling yields an energy of 4.3 millielectron volts for the lowest quantized phonon subband and a tube-tube (or "lattice") Debye energy of 1.1 millielectron volts, implying a small intertube coupling in bundles.

Structure-activity studies including a Psi(CH(2)-NH) scan of peptide YY (PYY) active site, PYY(22-36), for interaction with rat intestinal PYY receptors: development of analogues with potent in vivo activity in the intestine

Peptide YY (PYY) is a gut hormone that inhibits secretion and promotes absorption and growth in the intestinal epithelium. We have performed structure-activity studies with the active site, N-alpha-Ac-PYY(22-36)-NH(2), for interaction with intestinal PYY receptors. Investigation of aromatic substitutions at position 27 resulted in analogues that exhibited potent in vitro antisecretory potencies with N-alpha-Ac-[Trp(27)]PYY(22-36)-NH(2) exhibiting even greater potency than intact PYY. In vivo studies in dogs revealed that this analogue also promoted intestinal absorption of water and electrolytes during continuous intravenous and intraluminal infusion. Investigations carried out to identify features that would enhance stability revealed that incorporation of Trp(30) increased affinity for PYY receptors. A "CH(2)-NH" scan revealed that incorporation of reduced bonds at position 28-29 or 35-36 imparted greater receptor affinity. In general, disubstituted analogues designed based on the results of single substitutions exhibited good receptor affinity with N-alpha-Ac-[Trp(27),CH(2)-NH(35-36)]PYY(22-36)-NH(2) having the greatest affinity (IC(50) = 0.28 nM). Conservative multiple substitutions with Nle-->Leu and Nva-->Val also imparted good affinity. An analogue designed to encompass most of the favored substitutions, N-alpha-Ac-[Nle(24,28),Trp(30),Nva(31), CH(2)-NH(35-36)]PYY(22-36)-NH(2), exhibited a proabsorptive effect in dogs comparable to, but longer lasting than, that of intact hormone. Selected analogues also exhibited good antisecretory potencies in rats with N-alpha-Ac-[Trp(30)]PYY(22-36)-NH(2) being even more potent than PYY. However, the potencies did not correlate well with the PYY receptor affinity or the proabsorptive potencies in dogs. These differences could be due to species effects and/or the involvement of multiple receptors and neuronal elements in controlling the in vivo activity of PYY compounds. PYY(22-36) analogues exhibited good affinity for neuronal Y2 receptors but poor affinity for Y1 receptors. Also, crucial analogues in this series hardly bound to Y4 and Y5 receptors. In summary, we have developed PYY(22-36) analogues which, via interacting with intestinal PYY receptors, promoted potent and long-lasting proabsorptive and antisecretory effects in in vivo models. These compounds or analogues based on them may have useful clinical application in treating malabsorptive disorders observed under a variety of conditions.

Diagnostic potential of neutrophil elastase inhibitor complex in the routine care of critically ill newborn infants

It has been suggested that determination of the neutrophil elastase alpha1-proteinase inhibitor complex (E-alpha1PI) improves the diagnosis of bacterial infection in newborns. We evaluated the use of E-alpha1PI measurements in 143 newborns, consecutively admitted to a tertiary intensive care unit, employing a new random access assay and a sampling procedure that minimises post-collection artefacts. The 95% range for noninfected newborns was 20-110 microg/l up to the 5th day of life and 20-85 microg/l thereafter. The sensitivity as to the diagnosis of culture-proven bloodstream infection was 80% for E-alpha1PI, 86% for the immature to total neutrophil ratio, 64% for C-reactive protein and 37% for the total white blood cell count. The corresponding specificity amounted to 97%, 85%, 85% and 86%, respectively. E-alpha1PI increases preceded elevations of C-reactive protein by 18 h. Like C-reactive protein, E-alpha1PI levels did not distinguish between bloodstream infection and non-bacterial inflammatory responses. Results of E-alpha1PI became available within 1 h of collection and usually 2-3 h before manual leucocyte counts.

CONCLUSION

Determination of neutrophil elastase alpha1-proteinase inhibitor levels yields diagnostic advantages comparable to those of manual differential counts but provide faster turnaround times.

Experience and endocrine stress responses in neonatal and pediatric critical care nurses and physicians

OBJECTIVE

Critical care is a working environment with frequent exposure to stressful events. High levels of psychological stress have been associated with increased prevalence of burnout. Psychological distress acts as a potent trigger of cortisol secretions. We attempted to objectify endocrine stress reactivity.

DESIGN

Observational cohort study during two 12-day periods in successive years.

SETTING

A tertiary multidisciplinary neonatal and pediatric intensive care unit (33 beds).

SUBJECTS

One hundred and twelve nurses and 27 physicians (94% accrual rate).

INTERVENTIONS AND MEASUREMENTS

Cortisol determined from salivary samples collected every 2 hrs and after stressful events. Participants recorded the subjective perception of stress with every sample. Endocrine reactions were defined as transient surges in cortisol of >50% and 2.5 nmol/L over the baseline.

MAIN RESULTS

During 7,145 working hours, we observed 474 (12.5%) endocrine reactions from 3,781 samples. The mean cortisol increase amounted to 10.6 nmol/L (219%). The mean occurrence rate of endocrine reactions per subject and sample was 0.159 (range, 0-0.43). Although the mean raw cortisol levels were lower in experienced team members (>3 yrs of intensive care vs. <3 yrs, 4.1 vs. 4.95 nmol/L, p < .001), professional experience failed to attenuate the frequency and magnitude of endocrine reactions, except for the subgroup of nurses and physicians with >8 yrs of intensive care experience. A high proportion (71.3%) of endocrine reactions occurred without conscious perception of stress. Unawareness of stress was higher in intensive care nurses (75.1%) than in intermediate care nurses (51.8%, p < .01).

CONCLUSIONS

Stress-related cortisol surges occur frequently in neonatal and pediatric critical care staff. Cortisol increases are independent of subjective stress perception. Professional experience does not abate the endocrine stress reactivity.

Activation of NF-kappaB varies in different regions of the gastrointestinal tract during endotoxemia

The transcription nuclear factor-kappaB (NF-kappaB) regulates a large number of genes involved in the inflammatory response to sepsis and endotoxemia. We recently found that NF-kappaB is activated in the jejunal mucosa during endotoxemia, but the response of NF-kappaB in other parts of the gastrointestinal tract is not known. We hypothesized that NF-kappaB is differentially activated in different regions of the gastrointestinal tract during endotoxemia. NF-kappaB DNA binding activity was determined by electrophoretic mobility shift assay in mucosa of the stomach, jejunum, ileum, and colon from endotoxemic and saline-injected mice. Cytoplasmic levels of the NF-kappaB inhibitory proteins IkappaB-alpha and IkappaB-beta were determined by Western blot analysis. Endotoxemia increased NF-kappaB activity in mucosa of stomach, jejunum, and ileum, with jejunum responding to smaller doses of endotoxin than the other parts of the gastrointestinal tract. NF-kappaB DNA binding activity was not induced in colonic mucosa, even following administration of high doses of endotoxin. IkappaB-alpha and IkappaB-beta levels decreased in jejunal mucosa of endotoxin injected mice, concomitant with activation of NF-kappaB. The results suggest that during endotoxemia, NF-kappaB is activated in mucosa of stomach and small intestine, but not in colon, and that the jejunum is particularly sensitive to endotoxin.

Induction of the stress response in vivo decreases nuclear factor-kappa B activity in jejunal mucosa of endotoxemic mice

BACKGROUND

Results of previous studies suggest that the stress response protects cells and tissues by regulating proinflammatory mediators. The transcription factor nuclear factor-kappa B (NF-kappa B), normally sequestered in the cytoplasm by its inhibitory protein, I kappa B, regulates many genes involved in inflammatory responses to critical illness. Endotoxemia is associated with increased NF-kappa B activity in intestinal mucosa, but the effect of the stress response on endotoxin-induced NF-kappa B activation in intestinal mucosa is not known.

HYPOTHESIS

Induction of the stress response inhibits NF-kappa B DNA binding activity in jejunal mucosa during endotoxemia.

METHODS

The stress response was induced in mice by hyperthermia (42 degrees C) or injection with sodium arsenite (10 mg/kg). After 2 to 5 hours, mice were injected with endotoxin (lipopolysaccharide, 12.5 mg/kg) or a corresponding volume of sterile saline. One hour later, jejunal mucosa was harvested for preparation of nuclear and cytoplasmic extracts.

RESULTS

Mucosal levels of heat shock protein-72 increased after hyperthermia or treatment with sodium arsenite, consistent with induction of the stress response. The increase in NF-kappa B DNA binding activity and decrease in I kappa B-alpha levels seen after endotoxin injection were inhibited by previous induction of the stress response.

CONCLUSION

The protective effects of the stress response in vivo might, at least in part, be due to inhibited NF-kappa B activation.

Use of antibiotics in pediatric intensive care and potential savings

OBJECTIVE

Minimizing unwarranted prescription of antibiotics remains an important objective. Because of the heterogeneity between units regarding patient mix and other characteristics, site-specific targets for reduction must be identified. Here we present a model to address the issue by means of an observational cohort study.

SETTING

A tertiary, multidisciplinary, neonatal, and pediatric intensive care unit of a university teaching hospital.

PATIENTS

All newborns and children present in the unit (n = 456) between September 1998 and March 1999. Reasons for admission included postoperative care after cardiac surgery, major neonatal or pediatric surgery, severe trauma, and medical conditions requiring critical care.

METHODS

Daily recording of antibiotics given and of indications for initiation. After discontinuation, each treatment episode was assessed as to the presence or absence of infection.

RESULTS

Of the 456 patients 258 (56.6%) received systemic antibiotics, amounting to 1815 exposure days (54.6%) during 3322 hospitalization days. Of these, 512 (28%) were prescribed as prophylaxis and 1303 for suspected infection. Treatment for suspected ventilator-associated pneumonia accounted for 616 (47%) of 1303 treatment days and suspected sepsis for 255 days (20%). Patients were classified as having no infection or viral infection during 552 (40%) treatment days. The average weekly exposure rate in the unit varied considerably during the 29-week study period (range: 40-77/100 hospitalization days). Patient characteristics did not explain this variation.

CONCLUSION

In this unit the largest reduction in antibiotic treatment would result from measures assisting suspected ventilator-associated pneumonia to be ruled out and from curtailing extended prophylaxis.

Delay of extubation in neonates and children after cardiac surgery: impact of ventilator-associated pneumonia

OBJECTIVE

This study was undertaken to determine the delay of extubation attributable to ventilator-associated pneumonia (VAP) in comparison to other complications and complexity of surgery after repair of congenital heart lesions in neonates and children.

METHODS

Cohort study in a pediatric intensive care unit of a tertiary referral center. All patients who had cardiac operations during a 22-month period and who survived surgery were eligible (n = 272, median age 1.3 years). Primary outcome was time to successful extubation. Primary variable of interest was VAP Surgical procedures were classified according to complexity. Cox proportional hazards models were calculated to adjust for confounding. Potential confounders comprised other known risk factors for delayed extubation.

RESULTS

Median time to extubation was 3 days. VAP occurred in 26 patients (9.6%). The rate of VAP was not associated with complexity of surgery (P = 0.22), or cardiopulmonary bypass (P = 0.23). The adjusted analysis revealed as further factors associated with delayed extubation: other respiratory complications (n = 28, chylothorax, airway stenosis, diaphragm paresis), prolonged inotropic support (n = 48, 17.6%), and the need for secondary surgery (n = 51, 18.8%; e.g., re-operation, secondary closure of thorax). Older age promoted early extubation. The median delay of extubation attributable to VAP was 3.7 days (hazards ratio HR = 0.29, 95% CI 0.18-0.49), exceeding the effect size of secondary surgery (HR = 0.48) and other respiratory complications (HR = 0.50).

CONCLUSION

VAP accounts for a major delay of extubation in pediatric cardiac surgery.

Objectifying psychomental stress in the workplace--an example

BACKGROUND

Psychomental stress is a major source of illness and reduced productivity. Data objectifying physiological stress responses are scarce. We studied salivary cortisol levels in a highly stressful environment, the pediatric critical care unit. The aim was to identify targets for organizational changes, to implement these changes and to assess their impact on cortisol levels.

DESIGN

Repeated measurements observational cohort study (before and after intervention).

SUBJECTS

84 nurses working in two independent teams (A and B) in a 19 bed pediatric intensive care unit. Between study periods team A experienced a major exchange of experienced staff while the turnover rate in team B remained average.

MEASUREMENTS AND INTERVENTIONS

Salivary cortisol samples were collected every 2 h and after stressful events. Nurses in study period I showed elevated cortisol levels at the beginning of the late shift, interpreted as an anticipatory stress reaction. To ease conditions during the early part of the late shift (conflicting tasks, noise and crowding), we postponed the afternoon ward round, limited non-urgent procedures and introduced a change in visiting hours. The early shift, which was not affected by the intervention, served as control.

MAIN RESULTS

Both crude and adjusted analysis revealed a decrease of cortisol levels at the beginning of the late shift in team B (p = 0.0009), but not in team A (p = 0.464). The control situation showed no difference between teams and study periods.

INTERPRETATION

We demonstrated reduced cortisol secretions in one team following organizational changes, which was probably overridden by the disruption of social coherence in the second team.

Institutional and individual learning curves for focused abdominal ultrasound for trauma: cumulative sum analysis

OBJECTIVE

To evaluate both institutional and individual learning curves with focused abdominal ultrasound for trauma (FAST) by analyzing the incidence of diagnostic inaccuracies as a function of examiner experience for a group of trauma surgeons performing the study in the setting of an urban level I trauma center.

SUMMARY BACKGROUND DATA

Trauma surgeons are routinely using FAST to evaluate patients with blunt trauma for hemoperitoneum. The volume of experience required for practicing trauma surgeons to be able to perform this examination with a reproducible level of accuracy has not been fully defined.

METHODS

The authors reviewed prospectively gathered data for all patients undergoing FAST for blunt trauma during a 30-month period. All FAST interpretations were validated by at least one of four methods: computed tomography, diagnostic peritoneal lavage, celiotomy, or serial clinical evaluations. Cumulative sum (CUSUM) analysis was used to describe the learning curves for each individual surgeon at target accuracy rates of 85%, 90%, and 95% and for the institution as a whole at target examination accuracy rates of 85%, 90%, 95%, and 98%.

RESULTS

Five trauma surgeons performed 546 FAST examinations during the study period. CUSUM analysis of the aggregate experience revealed that the examiners as a group exceeded 90% accuracy at the outset of clinical examination. The level of accuracy did not improve with either increased frequency of performance or total examination experience. The accuracy rates observed for each trauma surgeon ranged from 87% to 98%. The surgeon with the highest accuracy rate performed the fewest examinations. No practitioner demonstrated improved accuracy with increased experience.

CONCLUSIONS

Trauma surgeons who are newly trained in the use of FAST can achieve an overall accuracy rate of at least 90% from the outset of clinical experience with this modality. Interexaminer variations in accuracy rates, which are observed above this level of performance, are probably related more to issues surrounding patient selection and inherent limitations of the examination in certain populations than to practitioner errors in the performance or interpretation of the study.

Interleukin-1beta induces complement component C3 and IL-6 production at the basolateral and apical membranes in a human intestinal epithelial cell line

In previous studies, stimulation of cultured enterocytes with IL-1beta resulted in production of IL-6 and complement component C3. The cellular mechanisms of these responses in the enterocyte are not fully understood. We tested the hypothesis that IL-1beta-induced C3 and IL-6 production is differentially regulated at the apical and basolateral membranes of the enterocyte. Caco-2 cells (a transformed human colonic carcinoma cell line) were grown in a 2-chamber system to full differentiation. The cells were treated with IL-1beta either at the apical or basolateral membrane, and C3 and IL-6 mRNA levels and release of C3 and IL-6 into the apical and basal chambers were determined. The release of C3 was greatest into the basal chamber regardless of whether the cells were stimulated at the apical or basolateral membrane. In contrast, the production of IL-6 was greatest at the cell membrane that was stimulated with IL-1beta. Stimulation of the Caco-2 cells with IL-1beta resulted in increased mRNA levels for C3 and IL-6 with no major differences noted when the cells were treated at the apical or basolateral membrane. The results suggest that enterocyte production and release of at least some acute phase proteins and cytokines are differentially regulated at the apical and basolateral membrane of the enterocyte after stimulation with IL-1beta.