Pseudomonas aeruginosa virulence expression is directly activated by morphine and is capable of causing lethal gut-derived sepsis in mice during chronic morphine administration.

OBJECTIVE: This study was designed to examine the effect of morphine administration on the intestinal mucus barrier and determine its direct effect on the virulence and lethality of Pseudomonas aeruginosa, one of the most frequent pathogens to colonize the gut of critically ill patients. BACKGROUND DATA: Surgical injury is associated with significant exposure of host tissues to morphine from both endogenous release and its use as a potent analgesic agent. Morphine use in surgical patients exposed to extreme physiologic stress is well established to result in increased infection risk. Although morphine is a known immunosuppressant, whether it directly induces virulence expression and lethality in microbes that colonize the human gut remains unknown. METHODS: Mice were implanted with a slow release morphine or placebo pellet with and without intestinal inoculation of P. aeruginosa created by direct cecal injection. Mucus production and epithelial integrity was assessed in cecal tissue via Alcian blue staining and histologic analysis. In vivo and in vitro P. aeruginosa virulence expression was examined using reporter strains tagged to the epithelial barrier disrupting protein PA-I lectin. P. aeruginosa chemotaxis toward morphine was also assayed in vitro. Finally, the direct effect of morphine to induce PA-I lectin expression was determined in the absence and presence of methylnaltrexone, a µ opioid receptor antagonist. RESULTS: Mice intestinally inoculated with P. aeruginosa and implanted with a morphine pellet demonstrated significant suppression of intestinal mucus, disrupted intestinal epithelium, and enhanced mortality; whereas exposure of mice to either systemic morphine or intestinal P. aeruginosa alone enhanced intestinal mucus without mortality, suggesting a shift in P. aeruginosa during morphine exposure to a mucus suppressing, barrier disrupting, and lethal phenotype. Direct exposure of P. aeruginosa to morphine in vitro confirmed that morphine can transform P. aeruginosa to a more virulent phenotype that is attenuated in part by methylnaltrexone. CONCLUSIONS: Morphine administration shifts intestinal P. aeruginosa to express a virulent phenotype and may play a role in its ability to causes lethal gut-derived sepsis in a susceptible host.

Red death in Caenorhabditis elegans caused by Pseudomonas aeruginosa PAO1.

During host injury, Pseudomonas aeruginosa can be cued to express a lethal phenotype within the intestinal tract reservoir-a hostile, nutrient scarce environment depleted of inorganic phosphate. Here we determined if phosphate depletion activates a lethal phenotype in P. aeruginosa during intestinal colonization. To test this, we allowed Caenorhabditis elegans to feed on lawns of P. aeruginosa PAO1 grown on high and low phosphate media. Phosphate depletion caused PAO1 to kill 60% of nematodes whereas no worms died on high phosphate media. Unexpectedly, intense redness was observed in digestive tubes of worms before death. Using a combination of transcriptome analyses, mutants, and reporter constructs, we identified 3 global virulence systems that were involved in the "red death" response of P. aeruginosa during phosphate depletion; they included phosphate signaling (PhoB), the MvfR-PQS pathway of quorum sensing, and the pyoverdin iron acquisition system. Activation of all 3 systems was required to form a red colored PQS+Fe(3+) complex which conferred a lethal phenotype in this model. When pyoverdin production was inhibited in P. aeruginosa by providing excess iron, red death was attenuated in C. elegans and mortality was decreased in mice intestinally inoculated with P. aeruginosa. Introduction of the red colored PQS+Fe(3+) complex into the digestive tube of C. elegans or mouse intestine caused mortality associated with epithelial disruption and apoptosis. In summary, red death in C. elegans reveals a triangulated response between PhoB, MvfR-PQS, and pyoverdin in response to phosphate depletion that activates a lethal phenotype in P. aeruginosa.

The human microbiome and surgical disease.

OBJECTIVE: The purpose of this review article is to summarize what is currently known about microbes associated with the human body and to provide examples of how this knowledge impacts the care of surgical patients. BACKGROUND: Pioneering research over the past decade has demonstrated that human beings live in close, constant contact with dynamic communities of microbial organisms. This new reality has wide-ranging implications for the care of surgical patients. METHODS AND RESULTS: Recent advances in the culture-independent study of the human microbiome are reviewed. To illustrate the translational relevance of these studies to surgical disease, we discuss in detail what is known about the role of microbes in the pathogenesis of obesity, gastrointestinal malignancies, Crohn disease, and perioperative complications including surgical site infections and sepsis. The topics of mechanical bowel preparation and perioperative antibiotics are also discussed. CONCLUSIONS: Heightened understanding of the microbiome in coming years will likely offer opportunities to refine the prevention and treatment of a wide variety of surgical conditions.

Prevention of siderophore- mediated gut-derived sepsis due to P. aeruginosa can be achieved without iron provision by maintaining local phosphate abundance: role of pH.

BACKGROUND: During extreme physiological stress, the intestinal tract can be transformed into a harsh environment characterized by regio- spatial alterations in oxygen, pH, and phosphate concentration. When the human intestine is exposed to extreme medical interventions, the normal flora becomes replaced by pathogenic species whose virulence can be triggered by various physico-chemical cues leading to lethal sepsis. We previously demonstrated that phosphate depletion develops in the mouse intestine following surgical injury and triggers intestinal P. aeruginosa to express a lethal phenotype that can be prevented by oral phosphate ([Pi]) supplementation. RESULTS: In this study we examined the role of pH in the protective effect of [Pi] supplementation as it has been shown to be increased in the distal gut following surgical injury. Surgically injured mice drinking 25 mM [Pi] at pH 7.5 and intestinally inoculated with P. aeruginosa had increased mortality compared to mice drinking 25 mM [Pi] at pH 6.0 (p < 0.05). This finding was confirmed in C. elegans. Transcriptional analysis of P. aeruginosa demonstrated enhanced expression of various genes involved in media alkalization at pH 6.0 and a global increase in the expression of all iron-related genes at pH 7.5. Maintaining the pH at 6.0 via phosphate supplementation led to significant attenuation of iron-related genes as demonstrated by microarray and confirmed by QRT-PCR analyses. CONCLUSION: Taken together, these data demonstrate that increase in pH in distal intestine of physiologically stressed host colonized by P. aeruginosa can lead to the expression of siderophore-related virulence in bacteria that can be prevented without providing iron by maintaining local phosphate abundance at pH 6.0. This finding is particularly important as provision of exogenous iron has been shown to have untoward effects when administered to critically ill and septic patients. Given that phosphate, pH, and iron are near universal cues that dictate the virulence status of a broad range of microorganisms relevant to serious gut origin infection and sepsis in critically ill patients, the maintenance of phosphate and pH at appropriate physiologic levels to prevent virulence activation in a site specific manner can be considered as a novel anti-infective therapy in at risk patients.

Handlebar injuries in children: should we raise the bar of suspicion?

Injury prevention strategies for child bicyclists have focused on helmet use to prevent head trauma. Handlebars are another source of injury. A retrospective review from 2005 identified 385 admissions to a Level 1 pediatric trauma center of which 23 (5.9%) were pedal cyclists. Four cases (<1.0%) of handlebar injuries were identified. Three children (two bicyclists, one riding a scooter) sustained handlebar impact to the neck. All children with neck injuries had subcutaneous emphysema. Two of the children had pneumomediastinum, which after work-up was managed nonoperatively. One child had a tracheal injury requiring operative intervention. Another child was struck in the upper abdomen resulting in a traumatic abdominal wall hernia requiring emergent exploration and hernia repair. Discordance exists between the apparently minor circumstances of handlebar trauma and the severity of injury sustained by bicyclists. Recognizing the mechanism of handlebar-related injuries and maintaining a high index of suspicion for visceral injuries aids in the diagnosis. The incidence of these injuries is underestimated due to insufficient documentation of the circumstances of injury events and a lack of applicable E-codes specific for handlebar injury.

Improved infant swallowing after gastroesophageal reflux disease treatment: a function of improved laryngeal sensation?

OBJECTIVE: The objective of this study was to describe improvements in pediatric swallowing after gastroesophageal reflux treatment. STUDY DESIGN: The authors conducted a retrospective database and chart review at two tertiary care children's hospitals. PARTICIPANTS: Patients (21 males, 7 females) ranged in age from 1 to 32 months. All patients had clinical evidence of gastroesophageal reflux disease (GERD) as well as evidence of dysphagia with aspiration (laryngeal vestibule and/or trachea) or hypopharyngeal pooling on flexible endoscopic evaluation of swallowing and sensation testing (FEESST) or videofluoroscopic swallow study (VSS). INTERVENTION: Each child underwent either medical or surgical intervention for control of their GERD. OUTCOME MEASURES: Outcome measures were change in laryngopharyngeal sensation and swallowing function with repeat swallow evaluation after GERD treatment. RESULTS: A significant improvement in both swallow function and sensory testing was demonstrated after GERD treatment. CONCLUSIONS: GERD may result in decreased laryngopharyngeal sensitivity, which may contribute to pediatric swallowing dysfunction. Control of GERD may improve swallow function. These findings have important clinical implications that need further study.

Sequential linear stapling technique for perineal resection of intractable pediatric rectal prolapse.

Rectal prolapse (RP), although most frequently encountered in the frail elderly, may also occur in children. This condition is most troublesome in the premature infant with significant associated comorbidities. Pediatric RP most often can be managed conservatively with expectant and/or judicious use of laxative-based bowel regimens. In rare instances of intractable RP, surgical intervention ranging from simple (sclerotherapy, Thiersch wire) to complex (perineal or transabdominal bowel resection) becomes necessary. We describe a modification of the Altemeier technique using a novel sequential linear stapling technique to treat intractable RP in a 5.0-kg infant with severe coexisting life-threatening comorbidities. The child had resumption of bowel movements on postoperative Day 1 and has had no recurrences. Sequential linear stapling technique for perineal resection of intractable pediatric RP appears to be a safe and potentially attractive alternative.

Ready for the frontline: is early thoracoscopic decortication the new standard of care for advanced pneumonia with empyema?

Video-assisted thoracoscopic decortication (VATD) has been established as an effective and potentially less morbid alternative to open thoracotomy for the management of empyema. However, the timing and role of VATD for advanced pneumonia with empyema is still controversial. In assessing surgical outcome, the authors reviewed their VATD experience in children with empyema or empyema with necrotizing pneumonia. The charts of 42 children who underwent VATD at our institution between July 2001 and July 2005 were retrospectively reviewed for surgical outcome. For purposes of analysis, patients were cohorted into four classes with increasing severity of pneumonia: 1 (-) intraoperative pleural fluid cultures, (-) necrotizing pneumonia, 18 (43%); 2 (+) pleural fluid cultures, (-) necrotizing pneumonia, 10 (24%); 3 (-) pleural fluid cultures, (+) necrotizing pneumonia, 6 (14%); 4 (+) pleural fluid cultures, (+) necrotizing pneumonia, 8 (19%). A P value of < 0.05 via Student's t test or Fischer's exact analysis was considered an indicator of significant difference in the comparison of group outcomes. VATD was successfully completed in all 42 patients with no mortality and without significant morbidity (82% had less than 20 cc blood loss). There was found to be no significant difference (p = NS) in time to surgical discharge (removal of chest tube) among all groups. Hospital length of stay postsurgery was found to be significantly increased between 1 and 4 (6 days vs 9 days; P = 0.038). 14/14 (100%) of children with necrotizing pneumonia were found to have evidence of lung parenchymal preservation with improved aeration on follow-up CT scan and/or chest x-rays. The authors conclude that early VATD in children with advanced pneumonia with empyema is indicated to avoid unnecessarily lengthy hospitalization and prolonged intravenous antibiotic therapy. Furthermore, early VATD can be safely performed in various stages of advanced pneumonia with empyema, promoting lung salvage, and accelerating clinical recovery.

Orbitofacial masses in children: an endoscopic approach.

OBJECTIVE: To describe an endoscopic approach for pediatric orbitofacial masses. DESIGN: A retrospective medical chart review. SETTING: Tertiary-care children's hospital. PARTICIPANTS: Patients (4 boys, 7 girls) ranged in age from 6 months to 11 years. All children underwent endoscopic excision of an orbitofacial mass. INTERVENTION: A single port approach was used in all but the initial case. The scalp incision was placed approximately 2.0 cm behind the frontal hairline. A subgaleal dissection was performed to minimize risk of nerve injury. Under endoscopic visualization, the mass was resected. MAIN OUTCOME MEASURES: Ability to successfully excise the mass endoscopically, and the incidence of complication. RESULTS: All lesions were successfully resected endoscopically. The surgical time varied from 30 to 105 minutes (mean, 50.5 minutes). Pathologic examination revealed 10 dermoid cysts and 1 neurofibroma. Two children had transient frontalis branch palsies that resolved spontaneously. There was 1 unilateral frontal hypoesthesia in the patient with the neurofibroma (an expected result). There were no other complications. CONCLUSIONS: An endoscopic approach to pediatric orbitofacial tumors is safe and effective. Although the risk of nerve injury may be higher, a thorough knowledge of frontotemporal anatomy and careful dissection will minimize this risk. The distinct advantage of an endoscopic approach is the absence of any facial scar in these young patients.

Bile decompression in children with histopathological evidence of pre-existing liver cirrhosis.

Although it is agreed upon by most that adequate and timely bile decompression can preserve or even improve existing liver function much debate centers on whether pre-existing liver cirrhosis can also be reversed. To help answer this question we analyzed data on 47 children with choledochal cyst disease (CD) who underwent simultaneous liver biopsy during bile decompression surgery. We collected data on two groups of children with CD spanning two different time periods: January 1985 through November 1994 (Group A) and June 1995 through November 1999 (Group B). In Group A 37 children (16 boys and 21 girls ages 5 days to 10 years) underwent simultaneous liver biopsy during elective definitive surgery for CD. In Group B ten children (five boys and five girls age one month to 7 years) underwent liver biopsy twice: first during initial cyst decompression for acute obstruction and second during elective definitive surgery after resolution of acute disease. Degree of liver cirrhosis was based on a modified World Health Organization classification system (0-IV). In Group A 15/37 (40.5%) had significant liver cirrhosis at time of biopsy (III or IV) with altered liver function in all cases; eight of nine had normal liver function on follow-up, six were lost to follow-up. In Group B seven of ten (70%) had less liver cirrhosis on pathology at second operation with three unchanged; nine of ten (90%) regained normal liver function. We conclude that bile duct obstruction is the main cause of liver cirrhosis in children with CD. Adequate and timely bile decompression can restore normal liver function and even reverse severe cirrhosis.

Hepatectomy in children under total hepatic occlusion.

Major ablative hepatic resection is often indicated in children with solid liver tumors, and reduction of operative blood transfusion is a primary goal. Total hepatic occlusion (THO) is an effective method that is well established in adults, yet its role in children is less well described. We describe our preliminary experience with THO in children assessing surgical outcome. The charts of seven children (ages 5 months to 7 years, weight 6-30 kg) who underwent THO during hepatectomy (four right and three left lobectomies) for liver tumors (hepatoblastoma in three, metastatic Wilm's tumor in two, mesenchymal hamartoma in one, and angiosarcoma in one) between January 1997 and June 2002 were reviewed. THO was established in all cases by clamping the supra- and infrahepatic inferior vena cava and the porta hepatis. Surgical parameters assessed included: 1) warm ischemia time, 2) operative blood transfusion, 3) operative complications, and 4) tumor resection margins. THO was successful in six of the seven cases (85.7%). In one case systemic hypotension unresponsive to fluid resuscitation developed at the outset with THO requiring conversion to pedicle clamping to perform the hepatectomy. Mean warm ischemia time during THO was 26 minutes (range 18-45 minutes). Mean estimated blood loss was 221 cm3 (range 50-800 cm3). Operative blood transfusion was required in one of six patients (15 cm3/kg). Excluding the "failed" THO case (intraoperative hypotension) there were no significant intraoperative or postoperative complications. All seven children had curative resections as indicated by "tumor-free" microscopic margins. We conclude that total hepatic occlusion can be performed safely and successfully for pediatric liver tumors. Operative blood transfusion appears to be minimized.

Primary insertion of a silastic spring-loaded silo for gastroschisis.

Gastroschisis is traditionally managed by emergency primary closure, with a temporary silo reserved for large defects unable to be closed primarily. We recently have begun primary Silastic (Dow Coming, Midland, MI) spring-loaded silo (SLS) closure followed by elective closure and report our preliminary experience. A total of 15 infants (weight range, 2.1-13.5 kg) at 2 different institutions were treated by SC by 3 different surgeons between 1998 and 2002. A 3-, 4-, or 5-cm (ring diameter) silo was used depending on size of abdominal wall defect. Elective closure was performed in the operating room or at the bedside. Surgical parameters assessed included success of SLS, peak inspiratory pressures (PIPs) pre- and post-SLS closure, total time of staged closure with SLS, time to full feedings, and intra- and postoperative complications. Fifteen of 15 infants were successfully treated by SLS closure followed by elective closure. Two of 15 (13.3%) experienced temporary dislodgement of the silo prior to permanent closure. In both cases, the silo was safely reinserted at the bedside. Comparison of PIP values measured at various stages of SLS closure revealed no significant difference (P > 0.05). Mean times to final fascial closure (3.7 days) and full enteral feedings (22 days) were similar to historical controls obtained from the surgical literature. In 1 case where there was associated intestinal atresia, SLS closure was effective in permitting concomitant elective closure and re-establishment of bowel continuity. All children are alive and well at the time of this report. SLS closure permits safe, gentle, and gradual reduction of the exposed viscera leading to successful permanent abdominal wall closure. Respiratory embarrassment and hemodynamic instability associated with emergent (primary) closure of large abdominal wall defects can thus be avoided.

Thoracoscopic thymectomy in children with myasthenia gravis.

Although conservative medical management is the mainstay in the treatment of myasthenia gravis (MG), severest forms of the disease often require surgical thymectomy. Thoracoscopic thymectomy (TT) represents a minimally invasive alternative to traditional thymectomy via sternotomy. We present our preliminary experience with TT as definitive treatment for severe forms of MG. The charts of 5 children (4 girls and 1 boy; age range, 11-17 years) who underwent TT for MG were retrospectively reviewed. TT was typically performed via left thoracoscopy using 4- or 5-mm ports with 1 of the ports enlarged at the end of the procedure for specimen retrieval. Thymic veins were identified and ligated with surgical clips in all cases. Surgical parameters assessed were the following: operating time, intra- and postoperative complications, length of postoperative stay, and resolution of symptoms. Follow-up ranged from 6 months to 2 years. All 5 TTs were successfully completed. In 1 case, right-sided thoracoscopy was added to ensure complete gland excision. Surgical pathology in all cases demonstrated complete excision. Mean operating time was 121 minutes (range 88 minutes to 188 minutes). There were no intra- or postoperative complications. Length of postoperative stay averaged 1.6 days (range, 1 to 3 days). Four of 5 (80%) had clear resolution of symptoms with 1 showing minimal resolution at 6 months. Thoracoscopic thymectomy is a safe and potentially attractive alternative to traditional thymectomy via median sternotomy in severe forms of myasthenia gravis. Complete thymectomy, the goal of traditional surgical treatment for myasthenia gravis, can effectively by achieved via this minimally invasive technique.

Minimally invasive surgery for pediatric solid neoplasms.

The role of minimally invasive surgery (MIS) in children with solid neoplasms is slowly evolving. MIS appears to be an ideal way to obtain diagnostic information (i.e., tissue biopsy) in children with solid neoplasms, but its role as an ablative/curative technique is controversial. We examined the safety, reliability, and outcome of decisions made on the basis of MIS performed in children with solid neoplasms. A total of 28 children (19 boys and nine girls; age range, 14 months to 17 years) with solid neoplasms underwent 29 MIS procedures between July 1, 2000 and June 30, 2002. Complications, biopsy results, and outcomes were reviewed. Successful ablation via MIS was defined as clear microscopic margins on permanent pathology and no evidence of remnant disease on follow-up diagnostic radiological examination. There were 20 thoracoscopic and nine laparoscopic procedures. Laparoscopy included purely diagnostic without tissue biopsy or simply determination of resectability (two), incisional biopsy (two), and excisional biopsy (five; two adrenalectomy and three oophorectomy). Thoracoscopy included 15 lung biopsies and five biopsies of mediastinal masses. Diagnostic accuracy was 100 per cent in all cases. MIS as an ablative technique was successful in 10 of 10 cases. No children were found retrospectively to have been inadequately treated via MIS. We conclude that MIS can be used safely and successfully to diagnose children with suspicious solid neoplasms. Furthermore MIS may have a role as an ablative/curative technique in carefully selected circumstances.

Median arcuate ligament syndrome in the pediatric population.

OBJECTIVES: Median arcuate ligament syndrome (MALS) is a vascular compression syndrome with symptoms that overlap chronic functional abdominal pain (CFAP). We report our experience treating MALS in a pediatric cohort previously diagnosed with CFAP. PATIENTS AND METHODS: We prospectively evaluated 46 pediatric (<21years of age) patients diagnosed with MALS at a tertiary care referral center from 2008 to 2012. All patients had previously been diagnosed with CFAP. Patients were evaluated for celiac artery compression by duplex ultrasound and diagnosis was confirmed by computed tomography. Quality of life (QOL) was determined by pre- and postsurgical administration of PedsQL™ questionnaire. The patients underwent laparoscopic release of the median arcuate ligament overlying the celiac artery which included surgical neurolysis. We examined the hemodynamic changes in parameters of the celiac artery and perioperative QOL outcomes to determine correlation. RESULTS: All patients had studies suggestive of MALS on duplex and computed tomography; 91% (n=42) positive for MALS were females. All patients underwent a technically satisfactory laparoscopic surgical release resulting in a significant improvement in blood flow through the celiac artery. There were no deaths and a total of 9 complications, 8 requiring a secondary procedure; 33 patients were administered QOL surveys. 18 patients completed the survey with 15 (83%) patients reporting overall improvement in the QOL. Overall, 31/46 patients (67%) reported improvement of symptoms since the time of surgery. CONCLUSIONS: MALS was found to be more common in pediatric females than males. Laparoscopic release of the celiac artery can be performed safely in the pediatric population. Surgical release of the artery and resultant neurolysis resulted in significant improvement in the blood flow, symptoms, and overall QOL in this cohort. The overall improvement in QOL outcome measures after surgery leads us to conclude that MALS might be earlier diagnosed and possibly treated in patients with CFAP. We recommend a multidisciplinary team approach to care for these complex patients.

Pseudomonas aeruginosa overrides the virulence inducing effect of opioids when it senses an abundance of phosphate.

The gut during critical illness represents a complex ecology dominated by the presence of healthcare associated pathogens, nutrient scarce conditions, and compensatory host stress signals. We have previously identified key environmental cues, opioids and phosphate depletion that independently activate the virulence of Pseudomonas aeruginosa. Opioids induce quinolone signal production (PQS), whereas phosphate depletion leads to a triangulated response between MvfR-PQS, pyoverdin, and phosphosensory/phosphoregulatory systems (PstS-PhoB). Yet how P. aeruginosa manages its response to opioids during nutrient scarce conditions when growth is limited and a quorum is unlikely to be achieved is important in the context of pathogenesis in gut during stress. To mimic this environment, we created nutrient poor conditions and exposed P. aeruginosa PAO1 to the specific k-opioid receptor agonist U-50,488. Bacterial cells exposed to the k-opioid expressed a striking increase in virulence- and multi-drug resistance-related genes that correlated to a lethal phenotype in C. elegans killing assays. Under these conditions, HHQ, a precursor of PQS, rather than PQS itself, became the main inducer for pqsABCDE operon expression. P. aeruginosa virulence expression in response to k-opioids required PqsE since ΔPqsE was attenuated in its ability to activate virulence- and efflux pumps-related genes. Extracellular inorganic phosphate completely changed the transcriptional response of PAO1 to the k- opioid preventing pqsABCDE expression, the activation of multiple virulence- and efflux pumps-related genes, and the ability of P. aeruginosa to kill C. elegans. These results indicate that when P. aeruginosa senses resource abundance in the form of phosphate, it overrides its response to compensatory host signals such as opioids to express a virulent and lethal phenotype. These studies confirm a central role for phosphate in P. aeruginosa virulence that might be exploited to design novel anti- virulence strategies.

Spleno-adrenal shunt: a novel alternative for portosystemic decompression in children with portal vein cavernous transformation.

PURPOSE: Children with portal vein cavernous transformation (PVCT) can develop life-threatening variceal hemorrhage from progressive portal hypertension. While spleno-renal shunt ± splenectomy is the most common portosystemic decompression surgery performed in children, we have adopted a modified spleno-adrenal (SA) shunt for complicated PVCT. We describe our 10 year experience focusing on technique evolution and treatment efficacy. METHODS: Between 2001 and 2011, 15 children (9 girls and 6 boys, ages 3-11 years, median: 6 years) with PVCT, portal hypertension, and hypersplenism were treated with SA shunt with splenectomy in Shanghai Children's Medical Center. All children in the study had endoscopy proven active esophageal variceal bleeding requiring multiple transfusions (mean: 4.2 units) with failed sclerotherapy (mean: 2.6 times). Greater omental vein pressure (GVP) approximating portal venous pressure was measured pre- and post-SA shunt. Pre- and post-operative ammonia levels were obtained. Follow-up ranged from 6 months to 10 years (mean: 4.2 ± 2 years). RESULTS: Intra-operative adrenal vein diameter and length ranged from 0.7 to 1.8 cm and 2 to 3 cm, respectively. Intra-operative GVPs pre-and post-SA shunt were (30 ± 11) and (22 ± 7) mmHg, respectively (p<0.01). On follow-up, there have been no recurrences of GI bleeding. Liver function tests remained normal in all children with the exception of elevated post-operative mean blood ammonia levels [Pre (18 ± 7) mmol/L, post (60 ± 17) mmol/L (p<0.05)] in all children. Ammonia levels normalized in all cases on outpatient follow-up. There have been no cases of hepatic encephalopathy, and all have normal age appropriate neurodevelopment (Bayley's assessment). Barium swallow and/or upper endoscopy showed interval resolution of esophageal varices in all children, and vascular ultrasound showed patent shunt anastomosis without stricture in 14 (93%). CONCLUSIONS: The left adrenal vein is a viable conduit for effective selective portosystemic decompression. Similar to the more traditional spleno-renal shunt, SA appears also to have the advantage of preventing hepatic encephalopathy preserving neurodevelopment, although the rise in post-operative ammonia levels was unexpected. Longer follow-up is needed to look for late signs of encephalopathy assessing neurodevelopment long term.

Redefining the role of intestinal microbes in the pathogenesis of necrotizing enterocolitis.

Neonatal necrotizing enterocolitis (NEC) remains an important cause of morbidity and mortality among very low birth weight infants. It has long been suspected that intestinal microbes contribute to the pathogenesis of NEC, but the details of this relationship remain poorly understood. Recent advances in molecular biology and enteric microbiology have improved our ability to characterize intestinal microbes from infants with NEC and from healthy unaffected newborns. The lack of diversity within the neonatal intestine makes it possible to study gut microbial communities at a high level of resolution not currently possible in corresponding studies of the adult intestinal tract. Here, we summarize clinical and laboratory evidence that supports the hypothesis that NEC is a microbe-mediated disorder. In addition, we detail recent technologic advances that may be harnessed to perform high-throughput, comprehensive studies of the gut microbes of very low birth weight infants. Methods for characterizing microbial genotype are discussed, as are methods of identifying patterns of gene expression, protein expression, and metabolite production. Application of these technologies to biological samples from affected and unaffected newborns may lead to advances in the care of infants who are at risk for the unabated problem of NEC.

Gut microbial gene expression in mother-fed and formula-fed piglets.

BACKGROUND: Effects of diet on the structure and function of gut microbial communities in newborn infants are poorly understood. High-resolution molecular studies are needed to definitively ascertain whether gut microbial communities are distinct in milk-fed and formula-fed infants. METHODOLOGY/PRINCIPAL FINDINGS: Pyrosequencing-based whole transcriptome shotgun sequencing (RNA-seq) was used to evaluate community wide gut microbial gene expression in 21 day old neonatal piglets fed either with sow's milk (mother fed, MF; n = 4) or with artificial formula (formula fed, FF; n = 4). Microbial DNA and RNA were harvested from cecal contents for each animal. cDNA libraries and 16S rDNA amplicons were sequenced on the Roche 454 GS-FLX Titanium system. Communities were similar at the level of phylum but were dissimilar at the level of genus; Prevotella was the dominant genus within MF samples and Bacteroides was most abundant within FF samples. Screened cDNA sequences were assigned functional annotations by the MG-RAST annotation pipeline and based upon best-BLASTX-hits to the NCBI COG database. Patterns of gene expression were very similar in MF and FF animals. All samples were enriched with transcripts encoding enzymes for carbohydrate and protein metabolism, as well as proteins involved in stress response, binding to host epithelium, and lipopolysaccharide metabolism. Carbohydrate utilization transcripts were generally similar in both groups. The abundance of enzymes involved in several pathways related to amino acid metabolism (e.g., arginine metabolism) and oxidative stress response differed in MF and FF animals. CONCLUSIONS/SIGNIFICANCE: Abundant transcripts identified in this study likely contribute to a core microbial metatranscriptome in the distal intestine. Although microbial community gene expression was generally similar in the cecal contents of MF and FF neonatal piglets, several differentially abundant gene clusters were identified. Further investigations of gut microbial gene expression will contribute to a better understanding of normal and abnormal enteric microbiology in animals and humans.