590 What Is the Most Appropriate Gastric Residual Volume to Identify Delayed Gastric Emptying in Critically Ill Patients?

test. The Kaplan-Meier method was used to estimate survival, and the log rank test used to assess the association of survival with serology status. A hazard ratio (HR) and 95% confidence interval (CI) was estimated using Cox Proportional Hazards regression to quantify survival in seropositives relative to seronegatives. Vital status was assessed using the National Death Index database with the assumption that any subject not indicated as deceased prior to 12/ 31/1996 was still alive up until then. A p-value <0.05 was considered significant. Results: A total of 19,766 blood samples were tested. Of 8,912 military recruits, 14 (0.2%) were positive for tissue transglutaminase and endomysial antibodies. By contrast, the rate was 1.0% and 0.9% among the 5,414 young and 5,440 older adults from the prospective [presentday] cohorts, respectively. The rate of positive CD-associated serology from 1948 to 1954 among a sample of military recruits was significantly lower than that among present-day young and older adult cohorts (p≤0.001 for both). All seropositive military recruits, among persons whose ethnicity was known, were white; no case had a diagnosis code (“clinical diagnosis”) of CD. Three seronegative subjects received a diagnosis of CD during followup. The 40-year mortality rate among the military recruit cohort was 16.8% for seronegatives, 7.1% for indeterminates (equivocal serology) and 50.0% for seropositives (HR=3.8, 95% CI: [2.0 to 7.3], p<0.001). Among the causes of death in seropositives were a cancer of the esophagus, a lymphoma, and a cancer of the larynx. Conclusions: There has been a dramatic increase in the prevalence of CD in the US population over the last 50-years. Cases with undiagnosed serologically-detected CD had nearly a 4-fold increased risk of death than those seronegative subjects, suggesting that undiagnosed CD is not benign.

591

BACKGROUND/AIM: Adult studies suggest that choline deficiency during parenteral nutrition (PN) may play a role in PN-associated liver disease. Intravenous lipid emulsions have significant quantities of phosphatidylcholine (PtdCho) but virtually no free choline (FCho). FCho is derived from the sequential breakdown of PtdCho to glycerophosphocholine (GPCho) then to phosphocholine (PCho) and finally FCho. There is no data about the concentration of whole blood FCho and choline metabolites in infants on chronic PN. We sought to examine the status of whole blood FCho and choline metabolites in infants on chronic PN therapy. METHODS: NICU infants on PN therapy were compared with agematched breastfed (BF)controls. The infants on PN received ≥50% of calorie intake from PN and intravenous lipids 3 g/kg/day for a minimum duration of 4-weeks. Percent total calories from PN (%PN) and whole blood concentrations of FCho (nmol/ml), PtdCho (nmol/ml), GPCho (nmol/ml) and PCho (nmol/ml) were measured in all subjects. Group comparisons were performed using paired T-tests and Pearson correlation with significance at p < 0.05. RESULTS: Twenty-eight (14 PN; 14 BF) infants were enrolled. The postnatal age of infants in both groups were (mean±SD) 7.3±4.5 (PN) vs. 7.4±3.6 (BF) weeks were similar. The %PN calorie intake was 78±19%. There were no group differences in whole blood concentrations of FCho and GPCho: 39.9±15.4 vs. 37.9±13.2 nmol/ml and; 16.4±14.5 vs. 18.8±17.5, p = NS respectively. PtdCho was increased in PN vs. BF infants: 1760±452 vs. 1470±221 nmol/ml, p = 0.02. Subjects receiving %PN >90% (n = 7) had reduced concentrations of PCho compared to infants receiving %PN <90% (n = 7) and BF (n = 14): 5.7±4.1 vs. 24.4±13.7 nmol/ml, p <0.01 and; 5.7±4.1 vs. 21.9±14.8 nmol/ml p <0.001 respectively. The concentration of PCho was directly correlated with its precursor GPCho in BF infants (r = 0.69, p <0.05) but not among the infants on PN, r = 0.2, p = NS. CONCLUSION: Chronic PN therapy was associated with increased concentrations of PtdCho, probably related to intravenous lipid therapy. Our finding of normal GPCho but decreased PCho during chronic PN therapy is evidence for impaired de novo FCho synthesis during PN therapy in infants. Furthermore, whole blood FCho was not helpful for assessing choline status. This observation suggests possibility of a block in transport of red blood cell FCho to plasma.

589 Relationship Between Galectin-10 Expression and Severity of Celiac Disease Abolished in the Presence of Gamma/Delta+T Cell Clonal Expansion Renato Cannizzaro, Valli De Re, Laura Caggiari, Maria Paola Simula, Michele Spina, Vincenzo Canzonieri Celiac disease (CD) patients are prone to develop T-cell lymphoma throughout a progressive accumulation of aberrant, clonal gamma/delta+ T-cells. It is supposed that high production of pro-inflammatory cytokines, and chronic antigenic stimulation, due to gluten ingestion, plays a key role in inducing inflammation, resistance to apoptosis and the emergence of these T-clones. Regulatory T-cells (Treg) maintain immunological self-tolerance by active suppression of auto aggressive T-cells. Among them, Tr1 subset plays a role in the suppression of naïve and memory T-cells through IL-10 production. The role of Tr1 in human diseases is not well understood, even because there are no specific markers able to identify these cells, however recently, Galectin-10 has been proposed as a marker for functional Tr1. To better understand pathogenetic mechanisms associated with CD and clonal T-cell proliferations we investigated galectin-10 expression from gut epithelium by 2D-DIGE approaches. Patients were selected and grouped for histological inflammatory degree and for gamma/ delta+T pattern defined by gamma-TCR genescan analysis. Groups consisted of 7 individuals with Marsh-0 (4/7 oligoclonal), 3 with a Marsh-1 or -2 (3/3 polyclonal) and 5 with Marsh3 (2/5 clonal gamma/delta+T). Control consisted of 4 individuals with excluded CD. We found, a parallel increase in galectin-10 levels and Marsh index in individuals with polyclonal gamma/delta+T cells (p=0.0092), while reduced levels were evidenced from patients with clonal gamma/delta+T cells and Marsh-3 (p=0.017). Data demonstrates up-production of galectin-10 in relation with inflammatory degree. From the critical role of Tr1 in immune regulation, we assume that galectin-10 up-expression is induce to an attempt to extinguish inflammation. By converse, down-regulation of galectin-10, found in the samples with clonal gamma/delta+T and Marsh-3, suggests a reduction in Tr1 function allowing to clonal proliferation. If these overexpanded clones are those more susceptible to a malignant progression reserve further exploration.

592 Enteral and Parenteral Nutrition Modulates Intestinal Permeability and Systemic Inflammation Claudia Guzy, Daniela Paclik, Axel U. Dignass, Bertram Wiedenmann, Andreas Sturm BACKGROUND: Nutritional support is required in many severely sick patients to prevent weight loss and catabolism. In this study we investigated the effect of enteral (EN) and parenteral (PN) nutrition on crucial functions of intestinal epithelial and T cells. METHODS: Intestinal monolayer integrity and tight-junction permeability were measured as transepithelial electrical resistance (TER) with a confluent Caco-2 monolayer cultured with or without 1% EN or PN, or a 1% amino acid mixture (AM) as control. To determine migration of epithelial cells into a wound, a well established wound healing model with IEC-6 cells was used. Flow cytometric analysis was used to determine apoptosis (annexin-V), cell activation (CD25), cytokine secretion (CBA), and proliferation (PI) of the intestinal epithelial cell line Caco-2 and of isolated and stimulated peripheral blood (PBMC) and lamina propria mononuclear cells (LPMC) cultured with or without 1 and 5% EN, AM or PN. RESULTS: When EN, AM or PN was added to confluent Caco-2 cells, the TER increased significantly within 24h compared to Caco-2 cells cultured without nutrition. Investigation of IEC-6 cell migration over a wounded edge revealed a significant enhanced cell migration by EN, AM and PN. DNA staining of epithelial cells showed no changes in cell cycle progression in the presence of EN, AM or PN. Direct contact of PN to epithelial cells significantly increased the number of apoptotic cells, whereas the addition of EN or AM did not induce or reduce apoptosis. With regard to T cells, activation of PBMC was significantly inhibited by EN and AM, but not PN. In contrast, in LPMC, EN and PN, but not AM, inhibited CD25 expression. Evaluating the effect of nutrition on T cell apoptosis, EN, but not PN or AM increased PBMC cell death, whereas in LPMC the tested substances did not change apoptosis. In addition, EN, but not PN, increased IL-6 and IL-1β secretion of PBMC, whereas in LPMC, EN and PN, reduced TNF-a and IL-10 secretion of LPMC. AM did not influenced cytokine secretion at all. CONCLUSION: EN and PN have a distinct capacity to affect epithelial and T cell function. We show that not only EN, but also PN stabilized the epithelial barrier and promoted wound healing In Vitro. With regard to T cells, PBMC activation was only inhibited by EN, which vice versa increased pro-inflammatory cytokine secretion. In mucosal T cells, both PN and EN reduced LPMC activation (an affect probably wanted in IBD) and reduced pro-inflammatory cytokine secretion. Our study provides evidence, that EN and PN are both capable to modulate intestinal barrier and T cell function and thus are capable to protect the host.

590 What Is the Most Appropriate Gastric Residual Volume to Identify Delayed Gastric Emptying in Critically Ill Patients? Nam Q. Nguyen, Katrina Ching, Robert J. Fraser, Ross N. Butler, Richard H. Holloway In critical illness, whilst feed intolerance (indirect marker of slow gastric emptying (GE)) has been defined by GRVs between 150ml and 250ml, recent reports suggest this volume should be increased to 450 ml to prevent unnecessary cessation of feeding. There are limited data on the relationship between GRV and the rate of GE in critically ill patients. Aim. To assess the relationship between GRVs and GE in critical illness. Methods. Concurrent assessments of 6-hrly GRV and GE (13C-octanoic breath test) were performed in 60 critically ill patients (29M; 58±2 yrs; APACHE II score: 22.6±1.2). The gastric emptying coefficient (GEC, normal=3.2-3.8) was calculated using standard techniques. The volumes of feed delivered, and 6-hrly gastric aspirates were recorded for 72 hours before and after GE measurement. Results. GE was delayed in 38 (63%) patients. There was a positive correlation between the GEC and (i) maximal 6-hourly GRVs (r=0.55, P=0.001), and (ii) total GRVs over 24 hours prior to BT (r=0.44, P<0.001). In patients with delayed GE, the 6-hrly GRV (159±24 vs. 78±21 ml, P=0.02) and the proportion of patients with a GRV≥250ml (24/38 vs. 4/22, P=0.001) were significantly greater than in those with normal GE. Although no patient with normal GE had GRV≥450ml, 29/38 of patients with delayed GE had GRV<450 ml. There is a trade-off between sensitivity and specificity of GRV in predicting slow GE as the cut-off volume increased (figure). On receiver operating characteristic (ROC) analysis, a GRV of 250ml had the highest area under the curve (0.88) with 73% sensitivity and 71% specificity as marker of delayed GE compared to 21% and 93%, respectively, for a GRV of 450ml. Conclusion. In critical illness, there is a moderate relationship between GRV and breath test measurement of GE. Although the ROC of a GRV of 250ml suggest this is preferable to 450ml as a marker of slow GE, its relationship to pulmonary aspiration warrant further study.

593 Antibiotic Prophylaxis Significantly Reduces Infection Rates At Paediatric Percutaneous Endoscopic Gastrostomy (PEG) Tube Insertion: Results of An RCT Michelle L. Wilson, Catherine E. Paxton, David Hoole, Fraser D. Munro, Peter M. Gillett, David C. Wilson Background and aim: Infection is a common complication and cause of morbidity of gastrostomy tube insertion. Although meta-analysis has shown the value of antibiotic prophylaxis for adults having PEG tube insertion, there have been no controlled trials in children. We aimed to establish evdence by performing an RCT of antibiotic usage on peristomal infection rates at paediatric PEG tube insertion. Methods: A double blind, randomised placebocontrolled trial of a single intravenous injection of Ceftriaxone or of 0.9 % saline at paediatric

A-81

AGA Abstracts

AGA Abstracts

Whole Blood Free Choline and Choline Metabolites in Infants On Chronic Parenteral Nutrition Therapy Timothy Sentongo, Praveen Kumar, Betsy Hjelmgren, Lisa Keys, Kishore Iyer, Alan L. Buchman