Faculty Bibliography

Hirschsprung-associated enterocolitis (HAEC) is a common and sometimes life-threatening complication of Hirschsprung disease (HD). Presenting either before or after definitive surgery for HD, HAEC may manifest clinically as abdominal distension and explosive diarrhea, along with emesis, fever, lethargy, and even shock. The pathogenesis of HAEC, the subject of ongoing research, likely involves a complex interplay between a dysfunctional enteric nervous system, abnormal mucin production, insufficient immunoglobulin secretion, and unbalanced intestinal microflora. Early recognition of HAEC and preventative practices, such as rectal washouts following a pull-through, can lead to improved outcomes. Treatment strategies for acute HAEC include timely resuscitation, colonic decompression, and antibiotics. Recurrent or persistent HAEC requires evaluation for mechanical obstruction or residual aganglionosis, and may require surgical treatment with posterior myotomy/myectomy or redo pull-through. This chapter describes the incidence, pathogenesis, treatment, and preventative strategies in management of HAEC.

Recurrent tracheoesophageal fistula (TEF) is difficult to diagnose and even more difficult to repair. The key to the diagnosis is an adequate contrast study and bronchoscopy. The key to the repair is complete separation of the esophagus from the trachea, with the placement of viable tissue between the two suture lines. I have presented a personal experience with 38 consecutive repairs of recurrent TEFs. The original series of 26 patients had three recurrences, all of which were re-repaired successfully. My more recent experience with the last 12 patients, who were far more complex, was also successful in ultimately repairing the recurrent TEFs.

PURPOSE: The primary toxic effects of methotrexate (MTX) are myelosuppression and/or intestinal mucositis. The objective of the present study is to investigate the effect of MTX on germ cell apoptosis and spermatogenesis in a rat. METHODS: Male Sprague-Dawley rats were divided into three experimental groups: control rats treated with vehicle; MTX-2 rats treated with one dose (20 mug/kg) of MTX given IP and killed on the second day; and MTX rats treated with IP MTX (20 mug/kg) and killed on day 4. Johnsen's criteria and the number of germinal cell layers in the testes were used to categorize the spermatogenesis. TUNEL assay was used to determine germ cell apoptosis. Western blotting was used to determine Bax and Bcl-2 protein levels. Statistical analysis was performed using the non-parametric Kruskal-Wallis ANOVA test, with p less than 0.05 considered statistically significant. RESULTS: On day 2, MTX-treated animals demonstrated minimal changes in the histological parameters of spermatogenesis, but germ cell apoptosis increased significantly (threefold increase, p = 0.002) compared to control rats. On day 4, MTX-treated rats demonstrated a trend toward a decrease in germ cell apoptosis, compared to day 2, and showed histological signs of impaired spermatogenesis (decreased number of germ cell layers and Johnsen's criteria). A significant increase in cell apoptosis in MTX-treated rats was correlated with higher Bax/Bcl-2 protein levels. CONCLUSIONS: MTX induced germ cell apoptosis and impaired spermatogenesis in rat testes.

Growing evidence suggests that n-3 PUFA and their specific lipid mediators can reduce the activity of inflammatory processes. In the present study, we evaluated the effects of oral n-3 PUFA supplementation on intestinal structural changes, enterocyte proliferation and apoptosis during methotrexate (MTX)-induced intestinal damage in the rat. A total of thirty-two male rats were divided into four experimental groups: control (CONTR) rats; CONTR-n-3 PUFA rats treated with oral administration of n-3 PUFA at a dose of 300 mug/kg once per d 72 h before and 72 h following vehicle injection; MTX rats treated with a single dose of MTX; MTX-n-3 PUFA rats treated with oral n-3 PUFA following the injection of MTX. Intestinal mucosal damage, mucosal structural changes, enterocyte proliferation and enterocyte apoptosis determined 72 h following MTX injection. Real-time PCR was used to determine B-cell lymphoma 2 (Bcl2)-associated X protein (Bax) and Bcl2 mRNA expression. Western blotting was used to determine phosphorylated extracellular signal-related kinase, beta-catenin, Bax and Bcl2 protein levels. MTX-n-3 PUFA rats demonstrated a greater jejunal and ileal bowel weight, greater ileal mucosal weight, greater ileal mucosal DNA and protein levels, greater villus height in the jejunum and ileum and crypt depth in the ileum, compared with MTX animals. A significant decrease in enterocyte apoptosis in the ileum of MTX-n-3 PUFA rats (v. MTX) was accompanied by decreased Bax mRNA and protein expression and increased Bcl2 mRNA levels. Thus, the treatment with oral n-3 PUFA prevented mucosal injury and improved intestinal recovery following MTX-injury in rats.

PURPOSE: While the endocrine action of the active metabolite 1,25-dihydroxyvitamin D (VtD) has been well characterized in relation to the maintenance of plasma calcium and phosphate homeostasis through regulation of intestinal absorption, recent research has focused on its autocrine and/or paracrine activities. Such activities have been best characterized in intestine, where VtD regulates cell differentiation and maturation. The purpose of this study was to evaluate the effect of VtD on enterocyte turnover in a rat model of short bowel syndrome (SBS). METHODS: Male rats were divided into four groups: sham rats underwent bowel transection, sham-VtD rats underwent bowel transection and were treated oral VtD, SBS rats underwent a 75 % bowel resection, and SBS-VtD rats underwent bowel resection and were treated with VtD. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined at sacrifice. Illumina's digital gene expression (DGE) analysis was used to determine VtD pathway-related gene expression profiling. VtD receptor (VDR) and its promoter, Bax and Bcl-2 mRNA expression were determined using real-time PCR. Western blotting was used to determine p-ERK, Bax and beta-catenin protein levels. RESULTS: From the total of 20,000 probes, 11 genes related to VtD signaling were investigated. Of these genes, five were found to be up-regulated in SBS versus sham animals with a relative change in gene expression level of 20 %, five remained unchanged, and one was down-regulated. VtD treatment in sham and SBS rats resulted in significant up-regulation of the VDR gene and its promoter's expression. SBS-VtD rats demonstrated a significant increase in all intestinal mucosal parameters compared to SBS animals. A significant increase in cell proliferation in SBS-VtD rats was accompanied by increased beta-catenin protein levels. A significant decrease in cell apoptosis in this group was correlated with lower Bax/Bcl-2 mRNA and protein levels. CONCLUSION: In a rat model of SBS, dietary supplementation with VtD stimulates enterocyte turnover, which correlates with up-regulated VtD receptor expression in the remaining small intestine.

OBJECTIVES: In the present study, we evaluated the effect of transforming growth factor-beta 2 (TGF-beta2)-enriched diet on enterocyte turnover and correlated it with TGF-beta2 receptor expression along the villus-crypt axis in a rat model of short bowel syndrome (SBS). METHODS: CaCo-2 cells were incubated with increasing concentrations of TGF-beta2. Alamar Blue reduction test was used for investigation of cell viability and evaluation of cell apoptosis was assessed by flow cytometry. Male rats were divided into 4 groups: Sham rats underwent bowel transection, Sham TGF-beta rats were treated with diet enriched with TGF-beta2, SBS rats underwent a 75% bowel resection, and SBS TGF-beta rats were fed a diet enriched with TGF-beta2 after bowel resection. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined at sacrifice. TGF-beta2r expression in villus tips, lateral villi and crypts was assessed by immunohistochemistry. The effect of TGF-beta2 on enterocyte turnover for each compartment was evaluated in correlation with TGF-beta2r expression. RESULTS: Incubation of CaCo-2 cells with TGF-beta2 resulted in a significant decrease in cell viability and increased cell apoptosis. TGF-beta2r expression in crypts increased in SBS rats (vs sham) and was accompanied by decreased cell proliferation and increased cell apoptosis following TGF-beta2 administration. A significant decrease in TGF-beta2r expression at villous tips in SBS rats was accompanied by a decreased cell apoptosis in this compartment following exposure to TGF-beta2-enriched diet. CONCLUSIONS: In a rat model of SBS, the inhibiting effect of TGF-beta2 on enterocyte turnover correlates with TGF-beta2 receptor expression along the villus-crypt axis.

Despite most children undergoing a successful pull through for Hirschsprung disease, a small portion of children are left with persistent stooling issues. Most of these stooling issues can be addressed by nonoperative approaches. However, in a small group of remaining children, a reoperation may be necessary. Most children who may need a redo pull-through procedure may have a persistent area of aganglionosis, unremitting enterocolitis, or a torsion or stricture of the pull-through segment. Each of these influences the approach the surgeon must take to correct the presenting problem. The chapter details the diagnostic approach as well as the operative techniques, which best deal with each of these complications.

Numerous cytokines have been shown to affect epithelial cell differentiation and proliferation through epithelial-mesenchymal interaction. Growing evidence suggests that platelet-derived growth factor (PDGF) signaling is an important mediator of these interactions. The purpose of this study was to evaluate the effect of PDGF-alpha on enterocyte turnover in a rat model of short bowel syndrome (SBS). Male rats were divided into four groups: Sham rats underwent bowel transection, Sham-PDGF-alpha rats underwent bowel transection and were treated with PDGF-alpha, SBS rats underwent a 75% bowel resection, and SBS-PDGF-alpha rats underwent bowel resection and were treated with PDGF-alpha. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined at euthanasia. Illumina's Digital Gene Expression analysis was used to determine PDGF-related gene expression profiling. PDGF-alpha and PDGF-alpha receptor (PDGFR-alpha) expression was determined by real-time PCR. Western blotting was used to determine p-ERK, Akt1/2/3, bax, and bcl-2 protein levels. SBS rats demonstrated a significant increase in PDGF-alpha and PDGFR-alpha expression in jejunum and ileum compared with sham animals. SBS-PDGF-alpha rats demonstrated a significant increase in bowel and mucosal weight, villus height, and crypt depth in jejunum and ileum compared with SBS animals. PDGF-alpha receptor expression in crypts increased in SBS rats (vs. sham) and was accompanied by an increased cell proliferation following PDGF-alpha administration. A significant decrease in cell apoptosis in this group was correlated with lower bax protein levels. In conclusion, in a rat model of SBS, PDGF-alpha stimulates enterocyte turnover, which is correlated with upregulated PDGF-alpha receptor expression in the remaining small intestine.

PURPOSE: To discuss developments in paediatric anaesthesia and explore the factors which have contributed to improved anaesthetic-related patient outcomes. METHODS: Narrative review of findings in the literature retrieved from MEDLINE/Pubmed and manual search. RESULTS: Adverse perioperative outcomes related to anaesthesia have been extensively debated over the past few decades, with studies implicating factors such as major human error and equipment failure. Case series and event registries have enlightened physicians on sources of error and patient risk factors such as extremes of age, comorbidity and emergent circumstances. Anaesthetic-related deaths in children fell from 6.4 per 10,000 anaesthetics in the early 1950s to as low as 0.1 per 10,000 anaesthetics by the end of the century. Advances in anaesthetic agents, techniques, monitoring technologies and training programmes in paediatric anaesthesia play a vital role in driving this downward trend. CONCLUSION: Despite substantial progress, there is still much room for improvement in areas such as adverse-event reporting, anaesthetic-related risk and late neurocognitive outcomes. Systematic reviews comparing paediatric patient outcomes after neuroaxial block versus general anaesthesia are currently unavailable. The future of paediatric anaesthesia will most likely be influenced by much-needed large prospective studies, which can provide further insight into patient safety and service delivery.

PURPOSE: Citation analysis within specific journals and subject areas has become a popular method to assess the impact of a journal, article or author. To date, only a few evaluations of citation reports have been published in the field of pediatric surgery. Twenty-six years after its inception, Pediatric Surgery International (PSI) is a firmly established journal in pediatric surgery. The aim of this study was to identify, analyze and categorize the characteristics of the 100 most-cited articles published in PSI since its founding in 1986. METHODS: The Web of Knowledge(SM), hosted by the Institute for Scientific Information, was searched with the all-database function for the 100 most-cited articles in PSI published from 1986 to the present. Each article was reviewed and the following parameters were recorded: number of citations, type of article, topic, year of publication, country of origin, institution and authorship. RESULTS: Between 1986 and 2012, 4,907 articles were published in PSI and 3,608 (73.53 %) of these were cited at least once. The 100 most-cited articles received a total of 3,309 citations with a mean of 33.09 (range 24-81). These articles were published between 1987 and 2007, with 73 articles published after 1997. Leading countries were USA (n = 15), Australia (n = 12), UK (n = 9) and Ireland (n = 9). Articles were categorized as followed: 92 original articles, 5 reviews and 3 case reports. 84 articles derived from clinical research and 16 derived from basic science. The most prolific authors were from 7 different institutions and published 37 articles, which received 1,213 (36.66 %) citations. CONCLUSION: The 100 most-cited articles published in PSI were predominately original articles from English-speaking countries dealing with clinical topics. This analysis may be of value to the editorial board and authors by providing some insights into what types of manuscripts appear to be of interest to the reading audience of PSI.