Effect of dietary fat on fat absorption and concomitant plasma and tissue fat composition in a rat model of short bowel syndrome.

The aim of this study was to investigate the effect of dietary fat on the time course of changes in fat absorption and tissue and plasma lipid composition in a rat model of short bowel syndrome (SBS). Male Sprague-Dawley rats underwent either a bowel transection with re-anastomosis (Sham rats) or 75% small bowel resection (SBS rats). Animals were randomly assigned to one of three groups: Sham rats fed normal chow (Sham-NC), SBS rats fed normal chow (SBS-NC), or SBS rats fed a high-fat diet (SBS-HFD). Rats were sacrificed on day 3 or 14. Body weight, food intake, food clearance (dry fecal mass), and fat clearance (total fecal fat) were measured twice a week. Fat and energy intakes were calculated according to the amount of ingested food. Food and fat absorbability were calculated as intake minus clearance and were expressed as percent of intake. Serum cholesterol, triglyceride, and albumin were measured. Total lipid composition of the liver, epididymal adipose tissue, and the small intestine was determined. Statistical analysis was performed by a Student's test, with p values <0.05 considered significant. Both food and fat absorbability diminished after bowel resection in rats fed NC. This was accompanied by a decrease in body weight gain, plasma triglyceride and protein levels, and total lipid content of the liver at day 3 and of a decrease in adipose tissue at day 14 following operation. SBS-HFD rats experienced a significant increase (p<0.05) in food absorbability after 7 days and fat absorbability after 3 days compared with Sham-NC and SBS-NC rats (p<0.05), as well as increases in serum cholesterol, triglycerides, and glucose compared with SBS-NC rats. On day 14, plasma lipid levels in SBS-HFD rats were not different from SBS-NC or control rats; however, albumin levels were higher. A high-fat diet increased total fat content of the liver early after operation. In conclusion, in a rat model of SBS, an early high-fat diet increased the absorptive capacity of the intestinal remnant as seen by increased food and fat absorbability. These findings suggest a benefit of a high-fat diet on intestinal adaptation in general and on lipid absorption in particular.

The effect of hypoxia on permeability and bacterial translocation in Caco-2 adult and I-407 fetal enterocyte cell culture models.

Hypoxia has been implicated in the breakdown of the intestinal epithelial barrier in animals, leading to bacterial translocation (BT); however, the mechanism of this hypoxic insult is unknown. To determine the effects of hypoxic injury in vitro on epithelial membrane integrity, transepithelial electrical resistance (TEER), mannitol permeability (Ma-Pm), and BT were measured in both an adult (Caco-2) and fetal (I-407) intestinal epithelial cell culture model. Caco-2 adult and I-407 fetal epithelial cell monolayers were treated with or without bacteria (1 x 10(7) Escherichia coli. C-25), and then incubated under either normoxic (5% CO(2) in room air) or hypoxic (5% CO(2) and 95% N(2)) conditions at 37 degrees C for 6 h. Hypoxia caused a 10% increase in Ma-Pm in the I-407 fetal cell model independent of the bacterial challenge. In contrast, a bacterial challenge in the Caco-2 adult model caused a 485% increase in Ma-Pm independent of hypoxia. Neither hypoxia, nor C-25 bacteria, for 6 h caused BT in either cell culture model. In the adult cell culture model, bacteria appear to mediate changes in epithelial barrier function, with hypoxia having no effect. On the other hand, hypoxia is the major factor in the loss of epithelial barrier function in fetal epithelium, but has no effect on adult epithelium. The data suggest that the breakdown of barrier function caused by a hypoxic insult is the primary stimulus for subsequent BT in neonates.

Interleukin-6 changes tight junction permeability and intracellular phospholipid content in a human enterocyte cell culture model.

Proinflammatory cytokines and secretory phospholipase A(2) (sPLA(2)) are elevated in patients with inflammatory bowel disease (IBD). We previously reported that the proinflammatory cytokine IL-6 increased the expression of sPLA(2) (a hydrolyzer of phosphatidylcholine) and decreased membrane integrity in an intestinal epithelial cell culture model. To determine the physiological effects of the IL-6 mediated increase in sPLA(2) on decreased epithelial layer integrity, we investigated alterations of intracellular/secretory phospholipid (PL) composition in a cell culture model. In addition, since other PLs may also mediate epithelial membrane activity, we investigated the effect of IL-6 on PL activity in a Caco-2 enterocyte culture model. Caco-2 cells were incubated for 72 h with IL-6 or media alone (control). Both media and cell lysate were analyzed for PL composition using thin-layer chromatography. The PL composition in the media did not show any differences between the two groups ( p>0.1). Total intracellular PL contents were also unchanged; however, IL-6 led to significant changes in PL composition including an increase in phosphatidylethanolamine (PE) and sphingomyelin (SM) and a decrease in phosphatidylcholine (PC) and lysophosphatidylcholine (LPC) ( p<0.05). Both PE and SM are known as inflammatory signaling factors involved in human IBD. Our study suggests that the decreased membrane integrity seen with IL-6 application may occur via intracellular PL alterations, rather than through the direct effects of sPLA(2).

Probiotics up-regulate MUC-2 mucin gene expression in a Caco-2 cell-culture model.

Enteral probiotics such as Lactobacillus casei GG (LGG) have been used in the treatment of a variety of intestinal disorders in infants and children, including diarrhea, malabsorption, and Clostridium difficile colitis. Previous studies have identified the gene locus for mucin (MUC-2) and its expression in Caco-2 cells. Others have demonstrated that mucin, located on the surface of the intestinal epithelium, inhibits bacterial translocation (BT). We previously demonstrated that both mucin and the probiotic bacterium LGG have an inhibitory effect on BT in both an in-vitro Caco-2 cell model and a neonatal rabbit model. We hypothesized that the decline in BT by LGG is mediated by up-regulation of epithelial MUC-2. Human enterocyte Caco-2 cells were grown to confluence and incubated at 37 degrees C with either medium (control group) or 10(4) or 10(8) LGG for 180 min. Non-adherent LGG was washed away. Caco-2 cells were then lysed, purified, and quantified for MUC-2 protein and mRNA. The addition of LGG to the enterocyte monolayer surface resulted in significantly ( P < 0.05) increased MUC-2 expression compared to the untreated monolayers. Protein densities for MUC-2 significantly ( P < 0.05) increased with LGG. Density (expressed as ratio to control group) was 8.6 +/- 1.3 in the low-dose group (10(4) LGG) and 15.6 +/- 2.3 in the high-dose group (10(8) LGG). LGG may thus bind to specific receptor sites on the enterocyte and stimulate the up-regulation of MUC-2, resulting in increased inhibition of BT.

Effect of low fat diet on lipid absorption and fatty-acid transport following bowel resection.

Low-fat diets (LFD) are used extensively in many different clinical conditions. However, the effect of this diet on lipid absorption and cellular long-chain fatty-acid (LCFA) transport is unknown. Fatty-acid translocase (FAT), the rat homologue of human CD36, is one of several LCFA plasma-membrane transport proteins that may play an important role in intestinal lipid uptake. The purpose of this study was to investigate the effects of a LFD on intestinal expression of FAT/CD36, enterocyte fatty-acid transport, and in-vivo lipid absorption in rats following bowel resection. Adult male Sprague-Dawley rats were divided into five experimental groups: normal rats fed normal chow(NR-NC) (10 kcal% fat), normal rats fed a LFD (NR-LFD) (3 kcal% fat), sham rats fed normal chow (Sham-NC), short-bowel syndrome rats fed normal chow (SBS-NC), and SBS rats fed a LFD (SBS-LFD). SBS rats underwent 75% small-bowel resection, while sham animals underwent bowel transection and reanastomosis. Food intake, fecal mass, and fecal fat were measured over the last 3 days before death on day 14. Final body weight, plasma lipids and protein, and tissue total lipids in liver, adipose tissue, and intestine were determined at death. Total RNA from the mucosa of the duodenum, jejunum, and ileum was extracted for Northern blot analysis to determine fatty-acid translocase (FAT)/CD36 mRNA levels. An established cellular LCFA transport assay was used to determine isolated enterocyte [3H]-oleate uptake. Students t-test was used to determine statistical significance (P < 0.05). NR-LFD rats demonstrated a small increase in overall food absorption and no change in fat absorption compared to NR-NC animals. A significant decrease in FAT/CD36 mRNA levels was seen in the duodenum and jejunum in NF-LFD rats (vs NR-NC) and was accompanied by reduced LCFA transport by isolated enterocytes from the jejunum and ileum. SBS-LFD rats demonstrated decreased FAT/CD36 mRNA levels in all three segments and a concomitant decrease in LCFA uptake enterocytes compared to the SBS-NC group. In addition, SBS-LFD rats showed significantly lower final body weight and plasma lipids compared to SBS-NC animals.

Effect of probiotics on enterocyte bacterial translocation in vitro.

Enteral probiotics such as Lactobacillus casei GG (LGG) have been used in the treatment of a variety of intestinal disorders in infants and children, including diarrhea, malabsorption, and Clostridium difficile colitis. We have previously demonstrated that the probiotic bacterium LGG has an inhibitory effect on bacterial translocation (BT) in a neonatal rabbit model. However, this in-vivo model is limited for investigating the cellular and molecular mechanisms responsible for probiotic inhibition of BT. The purpose of this study was to determine the efficacy of LGG in reducing the rate of Escherichia coli C25 (E. coli C25) translocation using an in-vitro enterocyte cell-culture model. Human colonic carcinoma (Caco-2) enterocytes were seeded in porous filters in the apical chamber of a two-chamber cell-culture system and grown for 14 days to confluence. The monolayers were incubated at 37 degrees C with LGG for 180 min. Non-adherent LGG was washed away prior to a 120-min incubation period with 10(5) CFU E. coli C25. E. coli that had translocated across the enterocyte monolayer were quantified by growing basal-chamber media samples on gram-negative bacteria-specific MacConkey's agar. In order to determine monolayer integrity, transepithelial electrical resistance (TEER) was measured across Caco-2 cells treated with LGG and E. coli. Statistical analysis was by ANOVA with P < 0.05 considered significant. LGG inhibited E. coli translocation at all LGG concentrations tested. The TEER ratio was not significantly altered by addition of LGG or E. coli (0.9 +/- 0.03 vs 0.8 +/- 0.05). These results demonstrate that the probiotic bacterium LGG inhibits BT of E. coli C25 in a dose-dependent manner in an in-vitro cell-culture model. This model should be valuable in investigating the cellular and molecular mechanisms involved in the inhibition of pathological enteral bacteria by probiotic agents.

The effect of phospholipids and fatty acids on tight-junction permeability and bacterial translocation.

The activity of phospholipase A2 (PLA2) is elevated in the intestinal epithelia of patients with inflammatory bowel disease (IBD). We recently reported that PLA2 mediates hydrolysis of phosphatidylcholine (PC) to lysophosphatidylcholine (L-PC) when both are applied to the apical surface of cultured EC monolayers, resulting in increased bacterial translocation (BT) and decreased transepithelial electrical resistance (TEER). Free fatty acids (FFA) are the other products of this reaction, however, their effect on Caco-2 cell permeability has not been reported. In addition to PC, other luminal phospholipids are present at the surface of the enterocyte. PLA2 may also mediate the hydrolysis of luminal phospholipids other than PC. The aim of this study was to examine the effects of phospholipids other than PC and common FFA on intestinal epithelial permeability and BT. Human Caco-2 enterocytes were grown to confluence on porous filters in the apical chamber of a two-chamber cell-culture system. Monolayer integrity and tight-junction permeability were measured as TEER. First, common FFA released by PC hydrolysis were determined using thin-layer chromatography (TLC). In separate experiments, monolayers were treated with phosphatidylethanolamine (PE), lysophosphatidylethanolamine (L-PE), or palmitoleic acid, oleic acids, linoleic acids, and arachidonic acid solubilized in solution with PC. The magnitude of BT was determined 2 h after treatment by adding Escherichia coli C25 to the apical chamber followed by quantitatively culturing basal-chamber samples. Statistical analysis was by the Kurosaki-Wallis test. TLC of PC samples incubated with PLA2 on the apical surface of Caco-2 monolayers demonstrated the production of palmitoleic acid, oleic acids, linoleic acids, and arachidonic acid. L-PE significantly decreased TEER compared to controls, but to a lesser degree than L-PC alone. L-PE had no effects on BT. Palmitoleic acid and oleic acid likewise significantly decreased TEER compared to controls, however, less than L-PC. All FFA tested had no effect on BT. Phospholipids applied to the apical surface of enterocytes, such as those found in vivo in mucus, can be hydrolyzed by the enzyme PLA2 resulting in lysophospholipid and FFA species that can alter enterocyte monolayer permeability. However, FFA and L-PL, other than L-PC, appear to have no effect to stimulate BT. This observation may have clinical implications in the pathogenesis and treatment strategies for IBD patients in whom enterocyte PLA2 activity has been shown to be elevated.

Effect of secretory immunoglobulin A on bacterial translocation in an enterocyte-lymphocyte co-culture model.

Intestinal secretory immunoglobulin A (sIgA) plays an important role in gut mucosal immunity in vivo; however, in-vitro enterocyte models for studying the mechanisms of these effects are lacking. This study utilizes a cell-culture model to investigate the effect of sIgA on bacterial translocation (BT) across human enterocytes co-cultured with human lymphoid cells (Raji cells). This model is intended to mimic in-vivo enterocyte/lymphocyte interactions found in intestinal follicle-associated epithelia. Human Caco-2 enterocytes were grown to confluence on porous filters in the apical chamber of a two-chamber cell-culture system. After differentiation, human B lymphoid cells (Raji cells) were added to the basolateral surface of Caco-2 monolayers for 3 days' co-culture, followed by washing away of unincorporated Raji cells. Transepithelial electrical resistance (TEER) was used to measure tight-junction permeability. Monolayers were treated with or without sIgA, IgG (negative control), or mannose (positive control). BT across the cell monolayer was determined 1.5 h after addition of Escherichia coli. Statistical analysis was by the Kruskal-Wallis test, P below 0.05 considered significant. In co-culture monolayers treated with sIgA, IgG, or mannose, there was no significant effect on TEER; however, the magnitude of BT across cells treated with sIgA (1.3 +/- 0.4 log10CFU/ml) and mannose (1.6 +/- 1.1 log10CFU/ml) was significantly decreased compared to PBS (3.9 +/- 0.4 log10CFU/ml) and IgG (2.9 +/- 0.6 log10CFU/ml) controls (P < 0.05). sIgA BT inhibition was dose-dependent. BT inhibition by sIgA and mannose was additive (0.5 +/- 1 log10CFU/ml). Inhibition of BT was negated when sIgA and mannose were removed by washing prior to E. Coli addition (3.6 +/- 0.5 log10CFU/ml), suggesting that both inhibitors act through bacterial binding.

Car surfing: an underreported mechanism of serious injury in children and adolescents.

BACKGROUND: Car surfing, in which participants stand on top of a moving vehicle as though it were a surfboard, has been reported as a cause of traumatic injury in only 5 cases in the literature. Over the last 8 years, however, the authors have treated 26 children, primarily adolescents, for injuries resulting from car surfing. This report describes the injuries and outcomes of this potentially underreported mechanism of injury. METHODS: Medical records of 26 patients treated for car surfing injuries between 1991 and 1999 were reviewed. Demographics, hospital course, and type and severity of injuries were analyzed. RESULTS: Eighteen boys (69%) and 8 girls (31%) with an average age of 15.7+/-3.4 years (range, 6 to 22) have presented with injuries related to car surfing. All patients had fallen from the hood, roof, or trunk of a moving motor vehicle, the majority falling from the hood (n = 13; 50%). Injury severity was evaluated using the Injury Severity Scores (ISS; 12.4+/-6.5), Revised Trauma Score (RTS; 7.5+/- 1.1) and Glasgow Coma Score (GCS; 13.5+/-3.2). Injury severity was equivalent between boys and girls (P>.05). Central nervous system injuries predominated, with closed head injuries occurring in 22 (85%) and loss of consciousness in 10 (39%). Skull fractures occurred in 11 (42%) and intracranial bleeding in 9 (35%). Long-term cognitive rehabilitation was necessary in 22 (85%) patients. Three patients (12%) had spinal column fractures, with 2 (8%) suffering permanent paralysis. Two extremity (8%) and 3 (11.7%) pelvic fractures occurred. Most patients (73%) suffered significant skin and soft tissue injuries. Two patients (8%) presented with solid visceral injuries, and 1 child died. CONCLUSIONS: Car surfing is an extremely high-risk behavior in children and adolescents that leads to significant morbidity, long-term disability, and is potentially fatal. The incidence of car surfing may be greater than has been reported previously; therefore, prevention programs aimed at discouraging this high-risk behavior in children and adolescents should be considered.

Evaluation of probiotic treatment in a neonatal animal model.

The clinical use of probiotic agents such as enteral Lactobacillus to enhance intestinal defense against potential luminal pathogens has been tested in vivo; however, an understanding of the mechanisms responsible for the observed protection is lacking. The purpose of this study was to evaluate the effects of Lactobacillus on bacterial translocation (BT) in a neonatal animal model. Newborn New Zealand white rabbit pups were enterally fed a 10% Formulac solution inoculated with or without a 10(8) suspension of ampicillin-resistant Escherichia coli K1 (E. coli K1A) and/or Lactobacillus casei GG (Lacto GG). Pups received either no bacteria (n = 10), Lacto GG (n = 8), E. coli K1A (n = 26), or a combination of Lacto GG and E. coli K1A (n = 33). On day 3, representative tissue specimens from the mesenteric lymph nodes (MLN), spleen (SPL), and liver (LIV) were aseptically harvested in addition to a small-bowel (SB) sample that was rinsed to remove luminal contents. The specimens were then cultured in organism-specific media. Statistical analysis was by one-way ANOVA with P values less than 0.05 considered significant. Neonatal rabbits receiving Lacto GG-supplemented formula exhibited a 25% decrease (P < 0.05) in small-bowel colonization by E. coli K1A. In addition, Lacto GG decreased the frequency of extraintestinal BT by 46% (P < 0.05), 61% (P < 0.05), and 23%, respectively, in the MLN, SPL, and LIV. We have shown that enterally-administered Lacto GG decreases the frequency of E. coli K1A translocation in a neonatal rabbit model. These results may have significant implications for the treatment of BT and sepsis in the human neonate and provide a model for further studies.

The effect of phospholipase A2 on bacterial translocation in a cell culture model.

The activity of phospholipase (PL)A2 is elevated in the intestinal epithelia of patients with inflammatory bowel disease (IBD). Recently, we reported that lysophosphatidylcholine (L-PC), the PLA2 hydrolysis product of phosphatidylcholine (PC), stimulates bacterial translocation (BT) in an enterocyte cell-culture model. These two observations stimulated us to examine the effects of extracellular PLA2 on intestinal epithelial permeability. Human Caco-2 enterocytes were grown to confluence on porous filters in the apical chamber of a two-chamber cell-culture system. Monolayer integrity and tight-junction permeability were measured by dextran blue (DB) permeability and transepithelial electric resistance (TEER). Monolayers were treated with PC, L-PC, or PLA2 with and without PC. The magnitude of BT was determined 2 h after treatment by adding Escherichia coli to the apical chamber followed by quantitatively culturing basal chamber samples. Thin-layer chromatography (TLC) was utilized to verify PLA2 hydrolysis of PC to L-PC. Statistical analysis was performed by one-way analysis of variance. The magnitude of BT across monolayers pretreated with PLA2 + PC significantly increased compared to either PC or PLA2 (6.83 +/- 0.069, 2.41 +/- 0.46, and 3.06 +/- 1.14 log10 colony forming units/ml, respectively, P < 0.05). Absence of DB-permeability in any group confirmed monolayer integrity. TLC of PL samples harvested from the apical monolayer surface confirmed PC hydrolysis. PLA2 mediates hydrolysis of PC to L-PC when both are applied to the apical surface of cultured enterocyte monolayers, resulting in increased BT and increased TEER with no damage to monolayer integrity. These observations may have implications in the pathogenesis and treatment strategies for IBD.

Historical changes in the postoperative treatment of appendicitis in children: impact on medical outcome.

BACKGROUND/PURPOSE: The introduction of managed care in the 1980s caused increased pressure to reduce costs for hospitalized patients. The authors hypothesized that these market forces have resulted in a decreased hospital stay and utilization of sophisticated diagnostic testing in children treated for appendicitis. If true, the impact of this paradigm shift on patient outcome is unknown. METHODS: Hospital records for 913 pediatric patients treated for appendicitis from 1974 to 1998 were reviewed retrospectively. Patients were stratified into those with perforated appendicitis (PA) and nonperforated appendicitis (NPA). Demographics, perioperative hospital course, diagnostic testing, complications, and long-term outcomes were analyzed after stratification into time intervals. RESULTS: Over time, children with NPA were treated with shorter antibiotic courses (P<.05) and were placed on a regular diet earlier (P<.05). These changes in treatment resulted in an earlier discharge (P<.05). The amount of time to become afebrile with a normal white blood cell count (WBC) did not change over time. Children with PA exhibited similar results with shorter antibiotic courses (P<.05), earlier dietary intake (P<.05) and earlier hospital discharge (P<.05) over time. In all children with appendicitis there was no significant difference in the rate of wound infections, abscesses requiring drains, readmission, or reoperations overtime. The utilization of abdominal radiographs (83%) and ultrasonography (USN; 40%) was high and remained unchanged over time. Utilization of computed tomography (CT scan) was low (4.3%) in the early decades and was not used as a preoperative test from 1991 to 1994. Given the high diagnostic accuracy of a pediatric surgeon for this disease, Bayesian analysis indicates that USN utilization rates should be 15%. CONCLUSIONS: The market pressures of managed care have resulted in a new treatment paradigm with an earlier discharge of all children with appendicitis. There has been no concomitant increase in the complication rate in either group as a result of this paradigm shift. Bayesian analysis indicates that USN and abdominal radiographs are overutilized in our institution.

Confirmation of translocated gastrointestinal bacteria in a neonatal model.

PURPOSE: The hypothesis that enteric bacteria translocate from the gastrointestinal (GI) tract to extraintestinal sites has been extensively studied. However, definitive evidence that spontaneous bacterial translocation and dissemination from the GI tract to extraintestinal sites occur in a neonatal model has been lacking. The aim of this study was to confirm this phenomenon by tracking enterally administered, plasmid-labeled bacteria to extraintestinal sites. MATERIALS AND METHODS: Escherichia coli 07:K1 (E. coli K1) with and without a nontransferable, ampicillin resistance plasmid (pGEM-7) were used in this study. Newborn New Zealand white rabbit pups were separated into three treatment groups: transformed E. coli K1 (E. coli K1 + pGEM-7, n = 20), nontransformed E. coli K1 (n = 12), and control pups (no bacteria, n = 7). Pups were enterally fed 10% Formulac solution supplemented with a suspension of bacteria respective to their group. After the pups fed twice daily for 2 days, representative tissue specimens from the small bowel (SB), mesenteric lymph nodes (MLNs), spleen (SPL), and liver (LIV) were aseptically harvested and tested for culture growth in ampicillin-supplemented medium. RESULTS: Positive growths of plasmid-induced ampicillin-resistant bacteria were detected in tissue specimens harvested from rabbits fed transformed E. coli K1, but were not detected in the other groups. CONCLUSION: This experiment demonstrated conclusively that transformed E. coli K1 fed to healthy rabbit pups spontaneously translocated from the intestinal lumen and subsequently disseminated to the mesenteric lymph nodes, spleen, and liver.

The effect of phospholipids and mucin on bacterial internalization in an enterocyte-cell culture model.

A primary component of the intestinal mucous layer that functions as a barrier to luminal bacteria is mucin, a high-molecular-weight glucoprotein. In addition, the mucous layer also contains other important elements such as phospholipids (PLs), which may effect bacterial translocation (BTL). It has been reported that mucin inhibits Escherichia coli translocation; however, the effect of PLs on intestinal permeability is still controversial. We have recently reported that the concentration of mucous PLs is higher in neonatal as compared to adult rabbits. The functional significance of these biochemical differences on BTL remains to be determined. The aim of this study was to evaluate the effect of PL and mucin composition on BTL in a human enterocyte-cell culture model. Human enterocyte Caco-2 cells were seeded in 24-well tissue-culture plates and grown for 14 days to confluence. The monolayers were pretreated with phosphate buffered saline as control, 10 mg/ml or 20 mg/ml mucin, 0. 5 mM or 1.0 mM PL mixture based on neonatal (NPL) and adult (APL) composition, and 10 mg/ml mucin with 0.5 mM either APL or NPL mixtures 30 min before a 120-min incubation period at 37 degrees C with 10(8) colony forming units (CFU) of E. coli C25. Non-internalized bacteria were killed by the addition of gentamicin. Internalized bacteria were quantified by counting CFU from enterocyte-cell lysates grown on MacConkey's agar. Mucin inhibited bacterial internalization, while both compositions of PLs promoted it. Mucin added to the PL solution also diminished the stimulatory effect of PLs on bacterial internalization. These results indicate that the increased concentration of PLs found in the intestinal mucous layer of neonates, and/or the alteration in the balance between PLs and mucin, may play a role in the increased BTL seen in neonates.

The effect of mucin on bacterial translocation in I-407 fetal and Caco-2 adult enterocyte cultured cell lines.

Although the intestinal mucosa forms a crucial barrier between the host and the environment, bacterial translocation (BT) occurs frequently in neonates and may be a source of sepsis. The intestinal mucous gel layer is thought to be a vital component of the gut barrier and is composed, in part, of a family of glycoproteins known as mucins. Our aim was to study the effects of mucin on BT in an enterocyte cell-culture model using a fetal (I-407) and an adult (Caco-2) intestinal cell line. I-407 and Caco-2 cells were grown to confluence on porous filters in a two-chamber Transwell system. The integrity of the monolayers was confirmed by transepithelial electrical resistance (TEER) and permeability using the macromolecule dextran blue. Cells were treated with mucin (40 mg/ml) prior to inoculation of 1 x 10(6) Escherichia coli C25. The magnitude of BT was determined quantitatively by culturing the samples from the basal chamber of the wells and was expressed as log 10 [Colony Forming Units (CFU)/ml]. Statistical analysis was performed by the Mann-Whitney U test with statistical significance at P < 0.05. Mucin inhibited BT across both fetal and adult cultured enterocyte monolayers; however, the inhibitory effect was less on the fetal cells compared to the adult cells. Dextran-blue studies showed that monolayers were intact throughout the experiments. Despite 98% inhibition of BT, mucin had a statistically significant effect on post-bacterial inoculation TEER in Caco-2 cells and no effect in I-407 cells. The ability of mucin, a mucous-barrier glycoprotein, to inhibit BT across immature intestinal enterocytes, as in the neonate, may be diminished compared to mature adult enterocytes.

Firearm ownership in households with children.

BACKGROUND/PURPOSE: Increased morbidity and mortality rates in children injured by firearms has been well documented during this past decade. The aim of this study was to determine the socioeconomic factors affecting firearm ownership in families with children living in suburban/rural versus inner-city environments, and to identify predictors of firearm ownership in these families. METHODS: Parents of children less than 19 years old seen in a suburban (n = 751) or inner-city hospital (n = 406) anonymously completed a questionnaire regarding firearm ownership. RESULTS: Firearm ownership was 54% in rural locations, versus 18% among inner-city residents (P< .05). Firearm ownership in white households was 45% versus 20% in African-American households (P< .05). Mean number of all types of firearms in white households was 3.38 versus 1.78 in black households (P< .001). Firearm ownership was 19% in the less than $20,000 income bracket, significantly lower than households with greater incomes, and was significantly lower in households in which parents had the least education (19.7%) versus those with college degrees (38.5%; P< .05). Firearm owners of rifles and shotguns significantly more often cited hunting, collection, and target shooting as reasons for owning firearms, in contrast to revolver owners who cited protection and collection as reasons for firearm ownership (P < .05). CONCLUSIONS: Firearm ownership is higher in rural, caucasian versus inner-city African-American residents and is significantly less in households with lower income and educational levels. Significant predictors for firearm ownership were number of parents in households, educational level of parents, and population of residence.

The effect of epidermal growth factor on bacterial translocation in newborn rabbits.

PURPOSE: Epidermal growth factor (EGF), which is present in breast milk, has both trophic and maturational effects on intestinal mucosa. The aim of this study is to determine the effect of EGF on spontaneous intestinal bacterial translocation (BT) in formula-fed newborn rabbits, who have a high incidence of BT compared with breast-fed newborn rabbits. METHODS: Sixty-one rabbit pups were divided into three groups: EGF(-), n=24, EGF(+), n=22, and breast-fed animals, n=15. Both the EGF(-) and EGF(+) groups were gavage fed a standard artificial formula three times daily. EGF was administered subcutaneously three times daily (1.5 microg/g body weight per day) in the EGF(+) group. The breast-fed group was fed by their mothers ad libitum. At 7 days of age, all rabbits were killed, and the mesenteric lymph nodes (MLN), liver, and spleen were cultured qualitatively for bacterial growth, while the cecum and ileum were quantitatively cultured. To determine the effect of EGF on mucus-producing cells, goblet cell numbers in the small intestine were quantified histologically. RESULTS: There was no BT to MLN, spleen, or liver in the breast-fed group. The incidence of BT to MLN and spleen was significantly lower in the EGF(+) compared with EGF(-) group; (EGF[+]: MLN, 45%; spleen, 32%; Liver, 27%; EGF[-]: MLN, 79%; Spleen 67%; Liver 29%; in EGF[+] MLN and Spleen P<.05 vEGF[-]). There was no significant difference in cecal and ileal bacterial colonization between the EGF(+) and EGF(-) groups. The number of goblet cells in the small intestine was significantly lower in the EGF(-) group compared with the EGF(+) group as follows: EGF(+), 14+/-3; EGF(-), 9+/-3; breast-fed, 11+/-5 goblet cells per 100 epithelial cell nuclei; P=.013. CONCLUSIONS: (1) EGF caused a significant decrease in spontaneous bacterial translocation in formula-fed newborn rabbits and was associated with an increase in the goblet cell number of the small intestine. (2) These changes occurred in spite of the fact that no changes in small bowel bacterial colonization were observed. (3) These results suggest, but do not prove, that EGF may provide protection for neonates from gut origin infection by improving the mucosal barrier function through increased goblet cell production, thus decreasing the incidence of spontaneous bacterial translocation in the newborn.

Changes, with age, in the phospholipid content of the intestinal mucus layer of the newborn rabbit.

BACKGROUND/PURPOSE: The high incidence of bacterial translocation in newborns is thought to be caused, in part, by the immaturity of the intestinal mucosal barrier. Recently, intestinal mucus phospholipids (PL) have been reported to be important factors in the function of this mucosal barrier. The aim of this study was to quantify changes, with age, in the intestinal mucus PL of the newborn rabbit. METHODS: Mucus was gently scraped from the small intestinal mucosal surface of rabbits of different ages (0, 7, 14, and 28 days old and adult; n = 6 for all groups). PL was extracted from the mucus and was separated by two-dimensional thin-layer chromatography. The isolated phospholipid spots were quantified for their phosphorus content. RESULTS: Total PL content of the mucus decreased significantly with age (day 0, 21+/-2; day 7, 16+/-4; day 14, 9+/-3; day 28, 2+/-1; adult, 1+/-1 micromol/g wet mucus; P = .0001). Phosphatidylcholine and phosphatidylethanolamine levels in the adult rabbits were significantly lower in comparison with the 0-, 7-, and 14-day-old pups (P < .05). In contrast, lysophosphatidylcholine and lysophosphatidylethanolamine were significantly higher in the 28-day-old and adult rabbits in comparison with the 0-, 7-, and 14-day-old pups (P < .05). Phosphatidylinositol + phosphatidylserine levels in 7-day-old rabbits was significantly higher compared with adult rabbits. There was no significant difference in the composition of sphingomyeline between groups. CONCLUSION: Significant changes in the content and composition of the intestinal mucus phospholipids were observed during the first month of life in rabbits.

Efficacy of the straight endorectal pull-through in the management of familial adenomatous polyposis--a 16-year experience.

From 1979 to 1995, 27 patients who had familial adenomatous polyposis (FAP) were treated at the authors' institution. Most patients (n = 23) presented as a result of a previous family history of FAP. Eighteen patients presented with symptomatic colonic disease that included bloody stools (n = 14), diarrhea (n = 10), and abdominal pain (n = 6). Treatment consisted of a total colectomy, rectal mucosectomy, and straight endorectal pull-through (ERPT) in 26 of 27 patients. One patient preferred to undergo an ileoanal J pouch reconstruction. A temporary diverting loop ileostomy was performed in 25 patients and closed at an average of 100 days after the ERPT. Follow-up has been achieved in 100% of the patients and ranges from 6 to 182 months with an average of 48 months. Postoperative complications included partial bowel obstruction (two patients, one requiring enterolysis); and mild pouchitis (one patient). Two of the 27 patients required proctectomy and permanent ileostomy procedures, one for rectal cancer that was present microscopically in the initial rectal specimen from the ERPT and the other because of recurrent anastomotic complications. No patient required revision of the straight pull-through to a pouch or takedown of the pull-through as a result of persistent diarrhea or dissatisfaction. All of the patients are continent, and 80% deny any soiling during bouts of gastroenteritis. The mean number of bowel movements reported was 10 per day at the first postoperative clinic visit with a gradual decreased to six per day after 2 years. Initial use of bulking (62%) and antimotility agents (88%) decreased significantly over the course of follow-up to 29% and 67%, respectively at the most recent follow-up (average, 48 months) of each patient. Pelvic sepsis, which occurs in 8% of most series of patients who have pouches, did not occur in any of our patients. Pouchitis, a common complication with pouches (23%), occurred in only one of the patients and was mild and easily treated medically. This series demonstrates that total colectomy with rectal mucosectomy and straight ERPT eliminates the risk of colorectal cancer and achieves continence with a low complication rate and excellent functional results and patient satisfaction.

Complications after gastric transposition in children.

BACKGROUND AND OBJECTIVE: Esophagogastrostomy with gastric transposition, a procedure for replacement of the esophagus in cases of esophageal atresia, is increasing in popularity among pediatric surgeons. This study was undertaken to document the differences between postoperative complications in children and those reported in adults. PATIENTS AND METHODS: The authors reviewed the medical records and radiologic images for details of complications in 6 children (5 boys and 1 girl) who underwent esophagogastrostomy with gastric transposition for esophageal atresia. Follow-up ranged from 18 months to 12 years. The observations were compared with complications in adults, as reported in the literature. RESULTS: The complications of gastric transposition were classified as early (up to 1 month after surgery) of late (more than 1 month after surgery). They included anastomotic leak (in 1 patient), hernia (in 1) and recurrent structure (in 3). In 1 patient mediastinal abscess developed secondary to esophageal perforation, which occurred during a dilation procedure for stricture. CONCLUSIONS: Postoperative complications of gastric transposition occur less commonly in children than in adults. Benign stricture, which may occur both early and late, is the most common problem.