The use of laparoscopic liver biopsies in pediatric patients with hepatic dysfunction following allogeneic hematopoietic stem cell transplantation.

Hepatic dysfunction following hematopoietic stem cell transplantation (HSCT) is common, but making the correct diagnosis can be challenging. Liver biopsies can serve as an important diagnostic tool when the etiology cannot be clearly determined by laboratory data, physical examination, and imaging studies. We reviewed 12 consecutive pediatric patients (seven males, five females, age 9-23 years) who received allogeneic HSCT and underwent a laparoscopic-guided liver biopsy for hepatic dysfunction of unknown etiology from 1998 to 2005. Biopsies were performed using a single-port technique with a 16 or 18 gauge, spring-loaded biopsy gun. The time from HSCT to biopsy ranged from 31 days to 821 days (median 92 days). No intra- or postoperative complications were observed. The initial clinical diagnosis was confirmed in seven patients, whereas the initial working diagnosis was inaccurate in the remaining five patients. Our results suggest that laparoscopic-guided liver biopsy is an informative and safe procedure in pediatric HSCT recipients; this approach helped delineate the true cause of hepatic dysfunction and changed our therapeutic approach in approximately 40% of the patients reviewed. While the safety record at our institution appears promising, a larger multi-institutional study would be necessary to more accurately describe the overall efficacy of this procedure in pediatric HSCT patients.

Altered development of intestinal intraepithelial lymphocytes in P-glycoprotein-deficient mice.

Intraepithelial lymphocytes (IEL) that reside in the intestinal epithelium are known to exhibit phenotypic and functional characteristics that are distinct from other T cells. We have recently shown that peripheral T cells exclusively express an isoform of P-glycoprotein (P-gp) encoded by the mdr1a gene, but do not require mdr1a expression for normal proliferative, cytokine, or cytotoxic responses. In the present study, we have used mdr1-type knockout (KO) mice to demonstrate that IEL also utilize mdr1a, but only preferentially, in that the mdr1b isoform can be expressed in the absence of mdr1a expression. We also report that a high level of P-gp activity appears to be necessary for the normal development of certain IEL subpopulations. In specific, while the total number of IEL was relatively unaffected by the absence of mdr1a expression, the proportions of CD8 alpha beta and TCR alpha beta+ IEL increased significantly in mdr1a and mdr1a/b KO mice at the expense of CD8 alpha alpha and TCR gamma delta+ IEL, respectively. Moreover, these subset alterations also appeared to have functional consequences, in that proliferative, IL-2, and IFN-gamma responses of IEL from KO mice were distinct from those of normal IEL. In summary, our data suggest that mdr1a expression is required for the development of certain IEL subpopulations, most notably TCR gamma delta+ cells, and thereby indirectly influences the balance of T cell subsets in the intestinal epithelium.

Inhibitory activity of intestinal intraepithelial lymphocytes.

BACKGROUND: Intestinal intraepithelial lymphocytes (iIEL) are the first line of lymphoid cells exposed to orally absorbed foreign antigen. Because of this unique position, we hypothesized that the iIEL down-regulates the immune response to foreign antigen to prevent broad sensitization. METHODS: One-way mixed lymphocyte cultures (MLCs) were performed with Brown Norway (BN) as the responder and irradiated Lewis rats as the stimulator. BN iIEL or control cells (irradiated BN spleen-thymus cells) were added to the MLCs to assess their inhibitory function. RESULTS: When iIEL cells comprised 0.63% of well volumes, a significant (p < 0.05) decline in MLC proliferation was seen. To determine whether this inhibitory action was mediated by a soluble factor, supernatant from iIEL cultured with irradiated Lewis spleen-thymus cells was added to MLCs and was compared with the addition of culture medium as the control group. The iIEL group proliferated significantly less (p < 0.05) than the control group. To further define the mechanism of action, iIEL-conditioned supernatant was treated with neutralizing antibody to transforming growth factor-beta (25 micrograms/ml) or control immunoglobulin. Treated supernatant was then added to an MLC, resulting in a partial loss of inhibitory action. CONCLUSIONS: The iIEL appears to significantly suppress a response to allogeneic stimuli via a mechanism mediated by the action of one or more soluble factors. Transforming growth factor-beta may well be one of the mediators of this inhibitory action.

Intestinal intraepithelial lymphocytes influence the production of somatostatin.

BACKGROUND: We have previously demonstrated that intestinal intraepithelial lymphocytes (iIELs) inhibit lymphocyte proliferation. Because somatostatin also prevents lymphocyte proliferation, we hypothesized that iIELs may influence production of somatostatin. METHODS: Isolates of intestinal epithelium that were obtained from Brown Norway (BN) rats and contained an iIEL-enriched population (defined as CD45+) were incubated with irradiated Lewis splenocytes for allogeneic stimulation. BN rat splenocytes incubated with irradiated Lewis splenocytes served as a control. Supernatants were harvested after 4 days and assayed for somatostatin by using a radioimmunoassay. RESULTS: The somatostatin level in the intestinal epithelium-conditioned supernatant was significantly higher than that of the control group (176 +/- 60 versus 10 +/- 2 fmol/ml; p < 0.05). Removal of the CD45+ cell subset resulted in a fifteenfold reduction in somatostatin levels. The CD45+ cell lysates had significantly higher levels of somatostatin than did CD45+ depleted cells (1304 +/- 531 versus 128 +/- 41 fmol/ml; p < 0.05). CONCLUSIONS: The isolates of intestinal epithelium produced significant amounts of somatostatin. Removal of the CD45+ cells caused a significant loss of somatostatin production. Intracellular levels of somatostatin appeared to be highest in the CD45+ subpopulation. These data suggest that iIELs (that is, CD45+ cells) may have a significant influence on the production of somatostatin and may be a source of somatostatin production. Production of somatostatin by iIELs may help modulate immune responses in gut-associated lymphoid tissue.

Effect of very delayed repair of congenital diaphragmatic hernia on survival and extracorporeal life support use.

BACKGROUND: Since November 1992, operative repair in neonates with congenital diaphragmatic hernia (CDH) at this institution was delayed until respiratory insufficiency had resolved. METHODS: A retrospective analysis was performed (n = 33) comparing delayed repair with our previously reported institutional experience with immediate repair from January 1988 to October 1992 (n = 66). Infants with severe genetic defects or moribund conditions or who were premature were not considered candidates for repair or extracorporeal life support (ECLS), but they were included in the survival analysis. Survival was defined as hospital discharge. Data were compared with an independent t test or Pearson chi-squared test. RESULTS: Mean age at repair was 8.9 +/- 4.5 days (range, 3 to 20 days). Eleven infants in the study group were placed on ECLS (33% versus 68% in the comparison group; p = 0.001). Six of these infants survived (55% versus 58% in the comparison group; p = 0.846). Of these survivors, one patient was repaired while on ECLS, and the remainder underwent repair after decannulation from ECLS. All 20 of the remaining candidates for repair survived without need for ECLS. Overall survival was 79% versus 56% in the comparison group (p = 0.027). CONCLUSIONS: Our current data suggest that very delayed repair of newborns with CDHs is associated with an increase in the overall survival and a decrease in the use of ECLS when compared with previous experience at this institution.

Effects of caerulein on rat small and large intestinal fluid transport in vivo.

We have examined the effect of caerulein on intestinal fluid transport in vivo. Rat jejunal, ileal, and colonic segments were perfused with a physiologic buffer for a 60-min control period, followed by a 60-min period after caerulein, prostaglandin E2 (PGE2), or saline (0.9%, w/v) were given by intramuscular (i.m) injection. At a dose of 5 micrograms/kg caerulein had no effect on ileal fluid transport. Lower doses of caerulein (300 ng and 1 microgram/kg) also had no effect. PGE2 significantly (P less than 0.05) inhibited net ileal absorption by 94 +/- 24% from pre-dose levels. Caerulein (300 ng/kg) had no effect (P greater than 0.05) on jejunal or colonic fluid transport. Intestinal fluid accumulation assessed by the 'enteropooling' assay did not increase after 30 ng or 1 microgram/kg of caerulein, whereas in animals given PGE2 of (5 mg/kg) the fluid accumulation more than doubled (P less than 0.001): control 1.59 +/- 0.15 ml; cerulein (1 microgram/kg) 1.36 +/- 0.20 ml; and PGE2 4.7 +/- 0.50 ml. Serum levels of caerulein (after a 1 microgram/kg dose), measured by radioimmunoassay, were elevated up to 30 min after i.m. injection. The data indicate that caerulein has no direct effect on rat small or large intestinal fluid transport.

Recent advances in the management of Hirschsprung's disease.

BACKGROUND: Major advances have occurred in the management of Hirschsprung's disease since Swenson described his definitive operation in 1948. These advances have occurred in the following areas: genetics, neurophysiology, definitive management in the newborn, total colonic aganglionosis (TCA), Hirschsprung's-associated enterocolitis (HAEC), intestinal neuronal dysplasia (IND), and laparoscopic and perineal approaches for definitive pull-through and redo pull-through operations. METHODS: This paper will focus on the definitive management of the newborn, TCA, and HAEC, areas in which we have had considerable experience at our institution. RESULTS: We have treated almost 90 newborns with the definitive pull-through with minimum morbidity. We have managed 25 patients with TCA, of whom 5 had total intestinal involvement and died. The remaining 20 have undergone a total colectomy and endorectal pull-through (ERPT), with zero mortality and a very acceptable stooling pattern and continence rate. Our experience with more than 350 patients with Hirschsprung's disease over the past 25 years has demonstrated an incidence of HAEC of between 20% and 30%. During this period, we have performed 19 redo pull-through operations, the majority of which were ERPTs, with results comparable with those seen with a primary pull-through operation. CONCLUSIONS: The major advances that have occurred in the management of Hirschsprung's disease include the definitive management of the newborn, our understanding of Hirschsprung's-associated enterocolitis and the treatment of this entity, and the recent successful management of the very complex form of this disease, total colonic aganglionosis.

Simplified insertion of a transpyloric feeding tube.

Placement of a transpyloric feeding tube is a common procedure done through a previous gastrostomy site. Conventional fluoroscopic and endoscopic methods can be tedious because of the difficulty in cannulating the pylorus. Described here is a simplified method to place a transpyloric feeding tube under fluoroscopy.

Management of Hirschsprung's disease in children with trisomy 21.

Thirteen infants and children with trisomy 21 have been treated for Hirschsprung's disease since 1975. Clinical presentation of Hirschsprung's disease included constipation (five); neonatal intestinal obstruction (four); enterocolitis (three); and meconium plug syndrome (one). Additional associated congenital anomalies occurred in 10 patients, of which complex cardiac disease accounted for 25% of the defects. Seven children underwent definitive operation: Duhamel pull-through (four); Soave pull-through (two); and anal myectomy (one). Satisfactory continence occurred in all but one child. Enterocolitis developed in seven patients (54%): two at diagnosis of Hirschsprung's disease; three after colostomy; and two after pull-through. Five children died (38%): one from enterocolitis, two from cardiorespiratory failure after recovery from enterocolitis, and two from end-stage cardiac disease. Children with trisomy 21 can safely undergo definitive operation for Hirschsprung's disease but are at high risk for developing enterocolitis and complications of associated cardiac disease.

Monitoring of intestinal transplant rejection.

Our results show that maltase, sucrase, and lactase activity are present at a normal level in nonrejecting small bowel transplants after an initial postoperative decline. This confirms that the disaccharide absorbing capacity of these grafts is intact. In allogeneic bowel, however, the levels of maltase and sucrase decline as histologic rejection occurs. These results suggest that serial maltase, sucrase, and possibly lactase levels in allogeneic intestinal transplants may serve as a useful adjunct in the monitoring of small bowel transplant rejection.

Parenteral nutrition-associated cholestasis.

Cholestasis is a major complication that occurs frequently in patients with the short bowel syndrome and accounts for the majority of morbidity and mortality in this group of patients. The exact cause of this condition is not known and the etiology is likely multifactorial. Many new mechanistic insights into this disease are discussed and have paved the way for future investigation. For now, prompt recognition, early initiation of enteral feeding, prevention of overfeeding with parenteral nutrition, and agents that induce bile flow may be useful to prevent this catastrophic morbidity.

Enterocolitis.

Enterocolitis continues to be the major cause of morbidity and mortality in patients with Hirschsprung's disease. The exact etiology of Hirschsprung's-associated enterocolitis is not known. This review focuses on the clinical aspects, etiology, and therapy of Hirschsprung's-associated enterocolitis.

Use of cholecystokinin to prevent the development of parenteral nutrition-associated cholestasis.

BACKGROUND: Neonates are at high risk for the development of parenteral nutrition-associated cholestasis when receiving a prolonged course of total parenteral nutrition (TPN). Although this cholestasis is of unknown etiology, it may result from a lack of gastrointestinal hormone formation, including cholecystokinin, which normally occurs after enteral feedings. METHODS: Two groups of neonates were studied. The treatment group consisted of 21 consecutive, prospectively enlisted neonates receiving TPN for > 14 days. The nontreatment group consisted of 21 infants from the 2 years preceding the study who were matched to the treatment group by gestational age, diagnosis, and duration of TPN. The major outcome determinant was direct bilirubin. Cholestasis was defined as a direct bilirubin > 2.0 mg/dL and was considered severe if the direct bilirubin was > 5.0 mg/dL after other causes were ruled out. RESULTS: The mean direct bilirubin levels in the nontreated group progressively rose over time, whereas the mean direct bilirubin the treated group remained level. The incidence of infants with a direct bilirubin > 2.0 mg/dL was 24% and 43% in the CCK+ and CCK- groups, respectively, and was not significant (p = .14). The percentage of infants with a direct bilirubin > 5.0 mg/dL was 9.5% and 38% in the treatment and nontreatment groups, respectively, and was significant, p = .015. CONCLUSIONS: Levels of direct bilirubin were lower in the treated compared with the nontreated group. These findings suggest that cholecystokinin prophylaxis in high-risk neonates may help prevent the development of parenteral nutrition-associated cholestasis.

Recurrence after laparoscopic and open Nissen fundoplication: a comparison of the mechanisms of failure.

BACKGROUND: Laparoscopic Nissen fundoplication as treatment for gastroesophageal reflux disease (GERD) in adults has a reported recurrence rate of 2-17%. We investigated the rates and mechanisms of failure after laparoscopic Nissen fundoplication in children. METHODS: All patients who underwent a laparoscopic Nissen fundoplication for GERD and who subsequently required a redo Nissen were reviewed (n = 15). The control group consisted of the most recent 15 patients who developed recurrent GER after an open Nissen, fundoplication. RESULTS: Between 1994 and 2000, laparoscopic Nissen fundoplication was performed in 179 patients. Fifteen patients (8.7%) underwent revision. The mechanisms of failure were herniation in four patients, wrap dehiscence in four, a too-short wrap in three, a loosened wrap in two, and other reasons in two. The reoperation was performed laparoscopically in five patients (33%). The failure mechanisms were different in the open patients: eight were due to slipped wraps; three to dehiscences; and two to herniations. CONCLUSION: The failure rate after laparoscopic Nissen is acceptably low. A redo laparoscopic Nissen can be performed safely after an initial laparoscopic approach.

Intravascular calcium deposits in a critically ill patient. Light- and electron-microscopic findings.

We describe a case of a 2-year-old girl with an unusual finding of amorphous hematoxyphilic substance in the pulmonary and myocardial vascular lumina. The patient had a prolonged history of intestinal obstruction necessitating extended periods of total parenteral nutrition. The patient terminally had hypercalcemia with levels reaching 4.63 mmol/L. The intravascular substance stains strongly positive for calcium, and weakly positive for fibrin. Electron microscopy shows that the substance has a distinctive configuration suggestive of calcium hydroxyapatite crystals.

Laparoscopic diagnosis and excision of Meckel's diverticulum.

Meckel's diverticulum is one of the primary concerns in the differential diagnosis of the pediatric patient with massive, acute gastrointestinal bleeding, intussusception, or abdominal pain of uncertain cause. The hospital course of two children with Meckel's diverticulum, successfully treated by laparoscopic excision, is presented, along with details of the operative procedure. Both patients recovered from the procedure without incident and were discharged at 24 and 48 hours after surgery. The authors believe a laparoscopic approach is safe and effective in the diagnosis and treatment of Meckel's diverticulum.

Split notochord syndrome with prolapsed congenital colostomy.

A case of split notochord syndrome associated with a prolapsed colostomylike dorsal enteric opening, a foreshortened colon, imperforate anus, and meningocele is presented. The surgical management of this disorder is discussed and available literature is reviewed. The patient was successfully treated with a combined, single-stage surgical correction.

Lingual thyroglossal duct cyst: a unique surgical approach.

Thyroglossal duct cyst (TGDC) is one of the more common causes of a pediatric neck mass. Lingual TGDC, which is located at the base of the tongue, is an unusual variant. Because of the oral pharyngeal location, lingual TGDC may cause dysphagia and respiratory distress. Previous investigators have advocated the use of a formal Sistrunk procedure for lingual TGDC. Herein the authors describe three children with a lingual TGDC in whom marsupialization of the cyst was performed, without excision. The follow-up period ranges from 2 to 5 years, and there has been no recurrence. Because of the low morbidity and high success rate associated with this approach, the authors recommend it for the treatment of lingual TGDC.

The pathophysiology of Hirschsprung's-associated enterocolitis: importance of histologic correlates.

To more clearly define the pathophysiology of Hirschsprung's-associated enterocolitis (HAEC), this study comprehensively evaluates the gastrointestinal tissue of a group of infants with clinical HAEC. A pathologic grading system that demonstrates a progressive sequence of histologic changes specific for HAEC is established. The grading system correlates closely with clinical enterocolitis and may prove to be a useful method for early detection of infants at risk for the development of clinical HAEC. A significant alteration of intestinal mucins with an increase in neutral mucins and a decrease in acidic-sulfomucins was identified in HAEC tissue specimens. Enterocyte-adherent organisms were present in 39% of HAEC tissue specimens. The pathogenesis of HAEC may result from an alteration in intestinal mucins that may allow for the subsequent adherence of enteropathogenic organisms to enterocytes. The enterocyte-adherent organisms have the potential to induce an enterocolitic process and may contribute to both the intestinal and systemic manifestations of HAEC.

Resolution of an infected intracardiac thrombus.

A 12-month-old patient had complete resolution of a central venous, catheter-related, infected intracardiac thrombus after 6 weeks of antibiotics, aspirin, and dipyridamole. Serial echocardiography documented the progressive decrease in thrombus size. Selected infants and children may safely undergo nonoperative management of infected intracardiac thrombi.