Fate of Pediatric Transport Medicine Abstracts 2011 to 2020: What Predicts Publication Success?

OBJECTIVE: Pediatric-neonatal transport research projects are presented at the American Academy of Pediatrics (AAP) Section on Transport Medicine (SOTM) scientific abstract program annually. Journal publication increases the impact of these projects. Our objectives were to determine the publication rate of transport abstracts and to identify factors predictive of publication success. METHODS: We reviewed all AAP SOTM abstracts accepted for presentation from 2011 to 2020 and assessed presentation format (oral/platform vs. poster), authors' professional degree (physician vs. nonphysician), and first author's trainee status. We searched PubMed, Ovid, and ResearchGate for publications by abstract title and authors and then compared published versus unpublished abstracts. Categorical variables were expressed as proportions and compared using the chi-square test or the Fisher exact test, whereas continuous variables were summarized using medians and interquartile ranges (IQRs) and compared using the Student t-test or the Kruskal-Wallis test as appropriate. A linear probability model was performed. RESULTS: Of 194 presented abstracts, 67 (34.5%) were published. The publication rate was significantly higher for oral/platform versus poster abstracts (P < .01), if the abstract was an oral/platform (probability increase by 19.5%, P < .01), and if the first author was a trainee (probability increase by 25.6%, p < 0.05). The constant was estimated as 24.9% probability of publication. Hence, if the first author was a physician, a trainee, and had an oral/platform presentation, there was an 85.8% chance of being published. The median (IQR) time to publication was 2 years (IQR: 2-4 years), with articles published the longest having the most citations. Articles were published in 27 different journals, with nearly half (33/67, 49.3%) being published in 3 journals. CONCLUSION: AAP SOTM abstracts have a 34.5% publication rate over the past 10 years, which is consistent with other medical specialties. Oral abstracts, physician first authors, and trainee first authors had a significantly higher success rate. Special emphasis should be placed nationally on supporting nonphysician transport professionals to publish their work.

Development of an Approach to Assessing Pediatric Fellows' Transport Medical Control Skills.

BACKGROUND AND OBJECTIVE: Pediatric interfacility transport teams facilitate access to subspecialty care, and physicians often guide management remotely as transport medical control (TMC). Pediatric subspecialty fellows frequently perform TMC duties, but tools assessing competency are lacking. Our objective was to develop content validity for the items required to assess pediatric subspecialty fellows' TMC skills. METHODS: We conducted a modified Delphi process among transport and fellow education experts in pediatric critical care medicine, pediatric emergency medicine, neonatal-perinatal medicine, and pediatric hospital medicine. The study team generated an initial list of items on the basis of a literature review and personal experience. A modified Delphi panel of transport experts was recruited to participate in 3 rounds of anonymous, online voting on the importance of the items using a 3-point Likert scale (marginal, important, essential). We defined consensus for inclusion as ≥80% agreement that an item was important/essential and consensus for exclusion as ≥80% agreement that an item was marginal. RESULTS: The study team of 20 faculty drafted an initial list of items. Ten additional experts in each subspecialty served on the modified Delphi panel. Thirty-six items met the criteria for inclusion, with widespread agreement across subspecialties. Only 1 item, "discussed bed availability," met the criteria for inclusion among some subspecialties but not others. The study team consolidated the final list into 26 items for ease of use. CONCLUSIONS: Through a consensus-based process among transport experts, we generated content validity for the items required to assess pediatric subspecialty fellows' TMC skills.

Pediatric Transport-Specific Illness Severity Scores Predict Clinical Deterioration of Transported Patients.

OBJECTIVE: The Transport Risk Assessment in Pediatrics (TRAP) and Transport Pediatric Early Warning Scores (T-PEWS) are transport-specific pediatric illness severity scores that are adjunct assessment tools for determining disposition of transported patients. We hypothesized that these scores would predict the risk of clinical deterioration in transported patients admitted to general pediatric wards. METHODS: Activation of a rapid response team (RRT) in the first 24 hours of admission was used as a marker of deterioration. All pediatric transports between March 2017 and February 2020 admitted via critical care transport were included. Transports to the emergency department (ED) were excluded. This retrospective chart review evaluated TRAP and T-PEWS scores at 3 points: (1) arrival of transport team at referring hospital, (2) admission to the children's hospital, and (3) RRT activation, if occurring within 24 hours of admission. RESULTS: There were 1137 team transports during this period. Three hundred ninety-nine patients transported to the ED were excluded, leaving 738 included patients; 405 (55%) admitted to the general wards and 333 (45%) admitted to the pediatric intensive care unit. Twenty-five patients admitted to the wards (6%) had an RRT activation within 24 hours of admission. Statistical analysis used 2-sample t tests. There was a statistically significant difference in scores for ward admissions between those who had RRT activation and those who did not. CONCLUSIONS: Both TRAP and T-PEWS can be used to predict the risk of clinical deterioration in transported patients admitted to general wards. These scores may assist in assessing which patients admitted to the wards need closer observation.

Core Components of a Pediatric Critical Care Transport Communication Curriculum: A Modified Delphi Approach.

OBJECTIVE: Interfacility transport of critically ill infants and children is an essential part of the care of children in the United States. However, there is tremendous variation in how transports are coordinated and performed. Pediatric critical care medicine (PCCM) fellows have differing experiences in their fellowships, and there is no standardized way of training medical command for the transport process. The aim of this study was to use a consensus-building process to establish core components of a PCCM transport curriculum focused on communication. METHODS: A national group of experts in transport medicine rated 51 total possible topics for their importance to include in a fellowship curriculum. Three rounds of surveys were completed. RESULTS: Fifty-two of 372 invitees (14%) participated in round 1. Consensus was reached to include 15 items in a PCCM curriculum. Twenty of 52 (38%) experts completed round 2, reaching consensus on 2 additional items. Seventeen of 20 (85%) experts completed round 3. No additional items reached consensus. CONCLUSION: Experts reached consensus on 17 core components to include in a PCCM fellowship transport communication curriculum. This curriculum could likely be adapted to train providers from different disciplines in the transport process.

Transport Medical Control Education for Pediatric Critical Care Fellows: A National Needs Assessment Study.

OBJECTIVES: Characterize transport medical control education in Pediatric Critical Care Medicine fellowship. DESIGN: Cross-sectional survey study. SETTING: Pediatric Critical Care Medicine fellowship programs in the United States. SUBJECTS: Pediatric Critical Care Medicine fellowship program directors. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We achieved a 74% (53/72) response rate. A majority of programs (85%) require fellows to serve as transport medical control, usually while carrying out other clinical responsibilities and sometimes without supervision. Fellows at most programs (80%) also accompany the transport team on patient retrievals. Most respondents (72%) reported formalized transport medical control teaching, primarily in a didactic format (76%). Few programs (25%) use a standardized assessment tool. Transport medical control was identified as requiring all six Accreditation Council for Graduate Medical Education competencies, with emphasis on professionalism and interpersonal and communication skills. CONCLUSIONS: Transport medical control responsibilities are common for Pediatric Critical Care Medicine fellows, but training is inconsistent, assessment is not standardized, and supervision may be lacking. Fellow performance in transport medical control may help inform assessment in multiple domains of competencies. Further study is needed to identify effective methods for transport medical control education.

Multicomponent Strategies to Prevent SARS-CoV-2 Transmission - Nine Overnight Youth Summer Camps, United States, June-August 2021.

Most U.S. overnight youth camps did not operate during the summer of 2020 because of the COVID-19 pandemic* (1). Several that did operate demonstrated that multiple prevention strategies, including pre- and postarrival testing for SARS-CoV-2, the virus that causes COVID-19, masking, and physical distancing helped prevent the introduction and spread of COVID-19; in contrast, camps that relaxed prevention strategies, such as requiring a single prearrival test without subsequent testing, experienced outbreaks (2-4). The availability of COVID-19 vaccines for persons aged ≥12 years enabled implementation of an additional prevention strategy that was not available in summer 2020. This study assessed the number of COVID-19 cases and potential secondary spread among 7,173 staff members and campers from 50 states, 13 countries, and U.S. military overseas bases at nine independently operated U.S. summer youth camps affiliated with the same organization. The camps implemented multiple prevention strategies including vaccination, testing, podding (cohorting), masking, physical distancing, and hand hygiene during June-August 2021. Vaccination coverage was 93% among eligible persons aged ≥12 years.† All staff members (1,955) and campers (5,218) received site-specific, protocol-defined screening testing, which included prearrival testing and screening tests during the camp session (38,059 tests). Screening testing identified six confirmed COVID-19 cases (one in a staff member and five in campers) by reverse transcription-polymerase chain reaction (RT-PCR) testing (screening test positivity rate = 0.02%). Three additional cases (in two staff members and one camper) were identified based on symptoms and were confirmed by RT-PCR testing. Testing for SARS-CoV-2, isolation, and quarantine in a population with high vaccination coverage resulted in no known secondary transmission of SARS-CoV-2 identified during camp. Implementation of multicomponent strategies is critical for prevention of COVID-19 outbreaks in congregate settings, including overnight youth camps.

New-onset Adrenal Insufficiency Presenting with Adrenal Shock in a Pediatric Patient.

This case report describes new-onset adrenal insufficiency and adrenal shock in an 11-year-old male complaining of two weeks of malaise and weight loss. He was lethargic and pale in appearance. Work-up revealed hypoglycemia and hyponatremia without evidence for an infectious process. He was transported via a pediatric critical care transport team to a regional pediatric intensive care unit (PICU). He required intravenous fluids and vasopressors prior to arrival in the PICU. He had generalized weakness, and hyperpigmentation of his face and extremities. Adrenal insufficiency was suspected, and glucocorticoid administration led to improvement. Cortisol level was undetectable. At time of discharge, he was prescribed daily glucocorticoid and mineralocorticoid replacement, along with a stress dose glucocorticoid plan.

The State of Neonatal and Pediatric Interfacility Transport During the Coronavirus Disease 2019 Pandemic.

OBJECTIVE: The coronavirus disease 2019 (COVID-19) pandemic has altered the provision of health care, including interfacility transport of critically ill neonatal and pediatrics patients. Transport medicine faces unique challenges in the care of persons infected with the severe acute respiratory syndrome coronavirus 2. In particular, the multitude of providers, confined spaces for prolonged time periods, varying modes (ground, rotor wing, and fixed wing) of transport, and the need for frequent aerosol-generating procedures place transport personnel at high risk. This study describes the clinical practices, personal protective equipment, and potential exposure risks of a large cohort of neonatal and pediatric interfacility transport teams. METHODS: Data for this study came from a survey distributed to members of the American Academy of Pediatrics Section on Transport Medicine. RESULTS: Fifty-four teams responded, and 47 reported transporting COVID-19-positive patients. Among the 47 teams, 25% indicated having at least 1 team member convert to COVID-19 positive. A small percentage of teams (40% ground, 40% fixed wing, and 18% rotor wing) reported allowing parental accompaniment during transport. There was no difference in teams with a positive team member among those that do (26%) and do not (25%) allow parents. There was a higher percentage of teams with a positive team member among teams that intubate (32% vs. 0%) and place laryngeal mask airways (34% vs. 0%) during transport. CONCLUSION: Our study shows that exceptional care during interfacility transport, including a family-centered approach, can continue during the COVID-19 pandemic. Teams must take steps to protect themselves, as well as the patients and families they serve, in order to mitigate the transmission of the SARS-CoV-2 virus.

Acute Myocardial Dysfunction and Hypereosinophilic Infiltrative Myocarditis Secondary to New-Onset Pediatric Acute Lymphoblastic Leukemia.

Myocardial infiltration by eosinophils leads to myocardial inflammation and fibrosis, resulting in restrictive hemodynamics. We describe an uncommon presentation of eosinophilic predominant acute lymphoblastic leukemia that manifested with hypereosinophilic infiltrative myocarditis. (Level of Difficulty: Advanced.).

Decreasing Usage of Lights and Sirens in an Urban Environment: A Quality Improvement Project.

INTRODUCTION: The risk of lights and sirens use in emergency medical services has been well documented. Our critical care transport team performs over 1,800 interfacility nonemergency medical services transports annually into a dense urban environment. Historically, we have utilized lights and sirens to navigate traffic patterns. The use exceeded industry standards. This quality improvement project was undertaken to decrease the use of lights and sirens. METHODS/RESULTS: The baseline use of lights and sirens in 2011 was 76% en route and 73% on return to the facility. We revised the internal policy guiding the appropriate usage of lights and sirens. In 2012, without an improvement in usage, a use justification process was implemented. By 2013, the use of lights and sirens was still high en route, but had decreased to 53% on the return trip. In 2014, we added accountability measures requiring justification, with a subsequent drop in 2015 to 14% en route and 13% on return. In the following 3 years, the transport teams have sustained lights and sirens use to 20% or below. CONCLUSIONS: This quality improvement initiative impacted team behavior and decreased the use of lights and sirens over 5 years, with sustained improvement at or below 20%. This improvement was accomplished through ongoing evaluation, education, data gathering, and open communication. There was no negative impact on patient outcomes during this time. Lights and sirens continue to be used when indicated.

Verbal Communication During Airway Management and Emergent Endotracheal Intubation: Observations of Team Behavior Among Multi-institutional Pediatric Intensive Care Unit In Situ Simulations.

OBJECTIVE: To assess health-care teams' verbal communication, an observable teamwork behavior, during simulations involving pediatric emergency airway management and intubation. METHODS: We conducted video-recorded, risk-informed in situ simulations at 5 hospitals with pediatric intensive care units in the Chicago, Illinois, area. Clinicians participated in their clinical roles (eg, attending physician, bedside nurse) and had access to hospital operational systems (eg, electronic health record, medical imaging, laboratory services). Video-recordings were transcribed; 3 pediatric critical care physicians analyzed the transcripts to assess preintubation communication: (a) the declaration of an airway emergency, (b) intubation medication request(s), and (c) preintubation medication administration. RESULTS: Ten pediatric intensive care unit simulations were analyzed. Statements to notify the care team of an airway emergency varied widely. In 3 simulations, a dosage for every medication was verbalized in the physician's initial medication request; however, in 4 simulations, a nurse was the first to verbalize the medication dosage(s) before administration. In 6 of the simulations where preintubation medications were administered, multiple requests for medications were verbalized. A clinician verbally confirmed that each medication was administered in only 2 of the simulations. CONCLUSIONS: No uniform statement was identified to declare an airway emergency among the care teams. Preintubation medication dosages were not consistently included in intubation medication orders, and frequently, there were multiple requests to obtain medications. Using standardized language to declare an airway emergency and verbally communicating medication requests and dosages and confirming administration may improve the quality of care in this critical event.

American College of Critical Care Medicine Clinical Practice Parameters for Hemodynamic Support of Pediatric and Neonatal Septic Shock.

OBJECTIVES: The American College of Critical Care Medicine provided 2002 and 2007 guidelines for hemodynamic support of newborn and pediatric septic shock. Provide the 2014 update of the 2007 American College of Critical Care Medicine "Clinical Guidelines for Hemodynamic Support of Neonates and Children with Septic Shock." DESIGN: Society of Critical Care Medicine members were identified from general solicitation at Society of Critical Care Medicine Educational and Scientific Symposia (2006-2014). The PubMed/Medline/Embase literature (2006-14) was searched by the Society of Critical Care Medicine librarian using the keywords: sepsis, septicemia, septic shock, endotoxemia, persistent pulmonary hypertension, nitric oxide, extracorporeal membrane oxygenation, and American College of Critical Care Medicine guidelines in the newborn and pediatric age groups. MEASUREMENTS AND MAIN RESULTS: The 2002 and 2007 guidelines were widely disseminated, translated into Spanish and Portuguese, and incorporated into Society of Critical Care Medicine and American Heart Association/Pediatric Advanced Life Support sanctioned recommendations. The review of new literature highlights two tertiary pediatric centers that implemented quality improvement initiatives to improve early septic shock recognition and first-hour compliance to these guidelines. Improved compliance reduced hospital mortality from 4% to 2%. Analysis of Global Sepsis Initiative data in resource rich developed and developing nations further showed improved hospital mortality with compliance to first-hour and stabilization guideline recommendations. CONCLUSIONS: The major new recommendation in the 2014 update is consideration of institution-specific use of 1) a "recognition bundle" containing a trigger tool for rapid identification of patients with septic shock, 2) a "resuscitation and stabilization bundle" to help adherence to best practice principles, and 3) a "performance bundle" to identify and overcome perceived barriers to the pursuit of best practice principles.

Education of pediatric subspecialty fellows in transport medicine: a national survey.

BACKGROUND: The transport of critically ill patients to children's hospitals is essential to current practice. The AAP Section on Transport Medicine has raised concerns about future leadership in the field as trainees receive less exposure to transport medicine. This study identifies the priorities of pediatric subspecialty fellows, fellowship directors and nursing directors in transport medicine education. METHODS: Internet based surveys were distributed to fellows, fellowship directors and nursing directors of transport teams affiliated with ACGME-approved fellowships in Neonatal-Perinatal Medicine (NPM), Pediatric Critical Care Medicine (PCCM), and Pediatric Emergency Medicine (PEM). Data collection occurred November 2013 to March 2014. RESULTS: Four hundred and sixty-six responses were collected (357 fellows, 82 directors, 27 nursing directors): Six curricular elements were ranked by respondents: Transport Physiology (TP), Medical Control (MC), Vehicle Safety (VS), Medicolegal Issues (ML), Medical Protocols (MP) and State and Federal Regulations (SFR). Fellows and fellowship directors were not significantly different: TP (p = 0.63), VS (p = 0.45), SFR (p = 0.58), ML (p = 0.07), MP (p = 0.98), and MC (p = 0.36). Comparison of subspecialties found significant differences: PEM considered TP less important than NPM and PCCM (p < 0.001, p < 0.001), VS less important than NPM (p = 0.001). PEM viewed SFR and MC more important than PCCM (p = 0.006, p = 0.002); ML more important than PCCM and NPM (p = 0.001, p < 0.001). PCCM ranked MC more important than NPM (p = 0.004). Nursing directors considered TP less important than NPM and PCCM (p < 0.001, p = 0.002). CONCLUSIONS: When ranking curricular elements in transport medicine, fellows and fellowship directors do not differ, but comparison of subspecialties notes significant differences. A fellow curriculum in transport medicine will utilize these results.

Development of an Evacuation Tool to Facilitate Disaster Preparedness: Use in a Planned Evacuation to Support a Hospital Move.

OBJECTIVES: Our institution relocated to a new facility 3.5 miles from our original location in Chicago on June 9, 2012. We describe the tools we developed to prepare, execute, and manage our evacuation and relocation. METHODS: Tools developed for the planned evacuation included the following: level of acuity and team composition classification, patient departure checklist, evacuation handoff tool, and a patient tracking system within the electronic health record. Incident Command structure was utilized. RESULTS: Monthly census tracking exercises were held beginning 12 months before the evacuation. Simulation drills began 6 months before the evacuation. The entire evacuation took less than 14 hours and there were no safety issues. A total of 127 patients were transported to the new facility: 45 patients were moved via the Neonatal/Pediatric Critical Care Transport Team, and the rest were moved with various team configurations. CONCLUSION: Documents developed for a planned evacuation can be used for any planned or unplanned evacuation. We believe the tools we used to prepare, execute, and manage our evacuation and relocation would assist any health care facility to be better prepared to safely and efficiently evacuate patients in the event of a disaster, or to create surge capacity, and relocate them to another facility. (Disaster Med Public Health Preparedness. 2017;11:479-486).

Performance of capnometry in non-intubated infants in the pediatric intensive care unit.

BACKGROUND: Assessing the ventilatory status of non-intubated infants in the Pediatric Intensive Care Unit (PICU) is a constant challenge. Methods to evaluate ventilation include arterial blood gas analysis (ABG), which is invasive and intermittent, and transcutaneous carbon dioxide monitoring (PtcCO2), which, while non-invasive, is also intermittent. A method that is non-invasive and continuous would be of great benefit in this population. We hypothesized that non-invasive capnometry via sidestream monitoring of exhaled carbon dioxide (CO2) would provide an acceptable measurement of ventilatory status when compared to ABG or PtcCO2. METHODS: Preliminary prospective study of infants less than one year of age admitted to the PICU in a large urban teaching hospital. Infants not intubated and not requiring non-invasive ventilation were eligible. A sidestream CO2 reading was obtained in a convenience sample of 39 patients. A simultaneous ABG was collected in those with an arterial catheter, and a PtcCO2 was obtained in those without. RESULTS: Correlation of sidestream CO2 with ABG was excellent (r(2) = 0.907). Sidestream correlated less well with PtcCO2 (r(2) = 0.649). Results were not significantly altered when weight and respiratory rate were added as independent variables. Bland-Altman analysis revealed a bias of -2.7 with a precision of ±6.5 when comparing sidestream CO2 to ABG, and a bias of -1.7 with a precision of ±9.9 when comparing sidestream CO2 to PtcCO2. CONCLUSIONS: Performance of sidestream monitoring of exhaled CO2 is acceptable clinical trending to assess the effectiveness of ventilation in non-intubated infants in the PICU.

Lysozyme-modified probiotic components protect rats against polymicrobial sepsis: role of macrophages and cathelicidin-related innate immunity.

Severe sepsis is associated with dysfunction of the macrophage/monocyte, an important cellular effector of the innate immune system. Previous investigations suggested that probiotic components effectively enhance effector cell functions of the immune system in vivo. In this study, we produced bacteria-free, lysozyme-modified probiotic components (LzMPC) by treating the probiotic bacteria, Lactobacillus sp., with lysozyme. We showed that oral delivery of LzMPC effectively protected rats against lethality from polymicrobial sepsis induced by cecal ligation and puncture. We found that orally administrated LzMPC was engulfed by cells such as macrophages in the liver after crossing the intestinal barrier. Moreover, LzMPC-induced protection was associated with an increase in bacterial clearance in the liver. In vitro, LzMPC up-regulated the expression of cathelicidin-related antimicrobial peptide (CRAMP) in macrophages and enhanced bactericidal activity of these cells. Furthermore, we demonstrated that surgical stress or cecal ligation and puncture caused a decrease in CRAMP expression in the liver, whereas enteral administration of LzMPC restored CRAMP gene expression in these animals. Using a neutralizing Ab, we showed that protection against sepsis by LzMPC treatment required endogenous CRAMP. In addition, macrophages from LzMPC-treated rats had an enhanced capacity of cytokine production in response to LPS or LzMPC stimulation. Together, our data suggest that the protective effect of LzMPC in sepsis is related to an enhanced cathelicidin-related innate immunity in macrophages. Therefore, LzMPC, a novel probiotic product, is a potent immunomodulator for macrophages and may be beneficial for the treatment of sepsis.

Tetrahydrobiopterin prevents platelet-activating factor-induced intestinal hypoperfusion and necrosis: Role of neuronal nitric oxide synthase.

OBJECTIVE: We reported previously that neuronal nitric oxide synthase (nNOS) is the predominant NOS in rat small intestine and is down-regulated by platelet-activating factor (PAF). The severity of the bowel injury induced by PAF is inversely related to its suppressing effect on nNOS. Here, we investigated whether intestinal perfusion is regulated by nNOS and whether tetrahydrobiopterin, a co-factor and stabilizer of nNOS, reverses PAF-induced intestinal hypoperfusion and injury. SETTING: Animal laboratory. DESIGN: We first examined nNOS regulation of splanchnic blood flow by measuring the perfusion of the heart, lung, ileum, and kidney in rats after a nNOS inhibitor. We then examined the protective effect of tetrahydrobiopterin on PAF-induced bowel injury, mesenteric hypoperfusion, and systemic inflammation. SUBJECTS: Adult male Sprague-Dawley rats. INTERVENTION: In part 1 of the experiment, rats were given 7-nitroindazole (a specific nNOS inhibitor, 50 mg.kg.day). In part 2 of the experiment, rats were treated with tetrahydrobiopterin (20 mg/kg) 5 mins before and 30 mins after PAF challenge (2.2 microg/kg, intravenously) MEASUREMENTS: Perfusion of the heart, lung, ileum, and kidney was measured at 1 and 4 days after 7-nitroindazole, using fluorescent microspheres. Intestinal injury and inflammation (myeloperoxidase content), blood perfusion, calcium dependent-NOS activity, and systemic inflammation (hypotension and hematocrit increase) were assessed 1 hr after PAF with and without tetrahydrobiopterin treatment. RESULTS: In part 1 of the experiment, 7-nitroindazole induced a long-lasting reduction of blood perfusion and inducible NOS expression selectively in the ileum but not in nonsplanchnic organs such as heart, lungs, and kidneys. In part 2, tetrahydrobiopterin protected against PAF-induced intestinal necrosis, hypoperfusion, neutrophil influx, and NOS suppression. It also reversed hypotension and hemoconcentration. Sepiapterin (2 mg/kg, stable tetrahydrobiopterin precursor) also attenuated PAF-induced intestinal injury. CONCLUSIONS: We conclude that nNOS selectively regulates intestinal perfusion. Tetrahydrobiopterin prevents PAF-induced intestinal injury, probably by stabilizing nNOS and maintaining intestinal perfusion.

Endotoxin, but not platelet-activating factor, activates nuclear factor-kappaB and increases IkappaBalpha and IkappaBbeta turnover in enterocytes.

Bacterial endotoxin (lipopolysaccharide; LPS) and platelet-activating factor (PAF) are important triggers of bowel inflammation and injury. We have previously shown that LPS activates the transcription factor nuclear factor (NF)-kappaB in the intestine, which up-regulates many pro-inflammatory genes. This effect partly depends on neutrophils and endogenous PAF. However, whether LPS and PAF directly activate NF-kappaB in enterocytes remains controversial. In this study, we first investigated the effect of LPS and PAF on NF-kappaB activation in IEC-6 (a non-transformed rat small intestinal crypt cell line) cells, by electrophoresis mobility shift assay and supershift, and found that LPS, but not PAF, activates NF-kappaB mostly as p50-p65 heterodimers. The effect was slower than tumour necrosis factor (TNF). Both LPS and TNF induce the expression of the NF-kappaB-dependent gene inducible nitric oxide synthase (iNOS), which occurs subsequent to NF-kappaB activation. We then examined the effect of LPS and TNF on the inhibitory molecules IkappaBalpha and IkappaBbeta. We found that TNF causes rapid degradation of IkappaBalpha and IkappaBbeta. In contrast, LPS did not change the levels of IkappaBalpha and IkappaBbeta up to 4 hr (by Western blot). However, in the presence of cycloheximide, there was a slow reduction of IkappaBalpha and IkappaBbeta, which disappeared almost completely at 4 hr. These observations suggest that LPS causes slow degradation and synthesis of IkappaBalpha and IkappaBbeta and therefore activates NF-kappaBeta via at least two mechanisms: initially, through an IkappaB-independent mechanism, and later, via an increased turnover of the inhibitor IkappaB. NF-kappaBeta activation precedes the gene expression of iNOS (assayed by reverse transcription-polymerase chain reaction), suggesting that LPS up-regulates iNOS via this transcription factor.