γ134.5-deleted HSV-1-expressing human cytomegalovirus IRS1 gene kills human glioblastoma cells as efficiently as wild-type HSV-1 in normoxia or hypoxia.

Pathophysiological hypoxia, which fosters the glioma stem-like cell (GSC) phenotype, is present in high-grade gliomas and has been linked to tumor development, invasiveness and resistance to chemotherapy and radiation. Oncolytic virotherapy with engineered herpes simplex virus-1 (HSV-1) is a promising therapy for glioblastoma; however, the efficacy of γ(1)34.5-deleted HSVs, which have been used in clinical trials, was diminished in hypoxia. We investigated the ability of a chimeric human cytolomegalovirus (HCMV)/HSV-1 virus, which expresses the human CMV protein kinase R evasion gene IRS1 and is in preparation for clinical trials, to infect and kill adult and pediatric patient-derived glioblastoma xenografts in hypoxia and normoxia. Infectivity, cytotoxicity and viral recovery were significantly greater with the chimeric virus compared with the γ(1)34.5-deleted virus, regardless of oxygen tension. The chimeric virus infected and killed CD133+ GSCs similarly to wild-type HSV-1. Increased activation of mitogen-activated protein kinase p38 and its substrate heat-shock protein 27 (Hsp27) was seen after viral infection in normoxia compared with hypoxia. Hsp27 knockdown or p38 inhibition reduced virus recovery, indicating that the p38 pathway has a role in the reduced efficacy of the γ(1)34.5-deleted virus in hypoxia. Taken together, these findings demonstrate that chimeric HCMV/HSV-1 efficiently targets both CD133+ GSCs and glioma cells in hypoxia.

Animal models for intestinal tissue engineering.

Although total parenteral nutrition prevents patients with short bowel syndrome from dying of starvation, having short bowel remains a severely debilitating condition. The best current treatment for inadequate absorptive surface area is through intestinal transplantation. However, this therapy is associated with significant morbidity and patients suffer from consequences of long-term immunosuppression. Additionally, the numbers of organs are limited. A new frontier in medicine is the field of tissue engineering. We will review the progress of intestinal bioengineering with a focus on the use of animal models. Investigators initially used autologous tissue as a patch to study intestinal regeneration. Subsequent studies focused on the use of absorbable biomaterials as a patch for tissue ingrowth. The most novel methodology consists of seeding a resorbable scaffold and implanting this construct to observe the regeneration of neointestine. Successful creation of esophagus, stomach, small bowel and colon has been demonstrated. Although these studies are preliminary, the results suggest that tissue-engineered intestine will become a real therapeutic option in the not too distant future for patients with inadequate intestinal tissue.

VEGF is upregulated in a neuroblastoma and hepatocyte coculture model.

BACKGROUND: We hypothesize that angiogenic factors are altered by the interaction between neuroblastoma cells and host tissues. MATERIALS AND METHODS: Human Chang hepatocytes and human neuroblastoma cells are cultured separately and in a noncontact, coculture system. Immunostaining for VEGF is performed on the cells. ELISA is used to detect vascular endothelial growth factor (VEGF), basic fibroblast growth factor, and interleukin-8 in the conditioned media. Human umbilical vein endothelial cells (HUVEC) are cultured with standard medium (control) and hepatocyte, neuroblastoma, and coculture conditioned media. After 48 and 72 h, cells are counted to determine proliferation. Finally, VEGF-blocking antibody is added to the HUVEC cultures with the conditioned media. RESULTS: VEGF is markedly elevated in the coculture medium compared to the media from hepatocytes or neuroblastoma grown alone [412.2 +/- 52 vs 235 +/- 35 or 74.5 +/- 28.5 (pg/10(6) cells), P < 0.05]. Other growth factors are almost undetectable in any of the media. Immunostaining for VEGF in the cocultured hepatocytes is decreased by almost 50%, but VEGF immunostaining is increased fourfold in the cocultured neuroblastoma cells. A significant increase in cell proliferation is seen at both 48 and 72 h when HUVEC are cultured with the coculture media. Cell proliferation is blocked with the addition of anti-VEGF antibody. CONCLUSION: The interaction of neuroblastoma with hepatocytes results in an increased production of VEGF. It stimulates endothelial cell proliferation and may enhance the tumor's metastatic potential in an autocrine fashion.

Free fluid on abdominal computed tomography scan after blunt trauma does not mandate exploratory laparotomy in children.

BACKGROUND/PURPOSE: The isolated finding of free intraperitoneal fluid on abdominal computed tomography (CT) scan after blunt trauma in adults is considered an indication for laparotomy by many trauma surgeons. The authors wished to determine if these guidelines are applicable to children. METHODS: A retrospective chart review was conducted. The authors included all children (< or =12 years of age) sustaining blunt abdominal trauma who were admitted to our institution between January 1, 1994 and November 1, 1998. RESULTS: There were 814 children admitted, and 437 had abdominal CT scans. Thirty-four studies showed free fluid associated with solid organ injuries, spine or pelvic fractures, or pneumoperitoneum, and were excluded. Thirty-two children had free fluid without associated injuries and formed the basis for the study. Five of these children underwent laparotomy based on the CT finding alone. The remaining 27 were observed with serial abdominal examinations and did not require surgical intervention. Only 1 of the 5 children who underwent surgery for the finding of isolated free fluid had a therapeutic laparotomy. In comparison, during the same period, 38 children underwent laparotomy after blunt injury based only on physical examination findings with a therapeutic laparotomy rate of 68%. The therapeutic laparotomy rate was significantly higher when the procedure was based solely on clinical examination as compared with the isolated finding or free fluid on the abdominal CT (26 of 38 v 1 of 5, P < .05). CONCLUSION: In contrast to adults, finding isolated free fluid on abdominal CT scans in children after blunt trauma does not dictate immediate surgical exploration.

Neuroblastoma and hepatocyte coculture conditioned media alter apoptosis.

BACKGROUND: Neuroblastoma is a childhood tumor that often displays unusual biological behavior. The tumor may present with widespread metastases that are unresponsive to aggressive treatment. At other times, both the metastases and the primary tumor may spontaneously regress without treatment. Apoptosis, or programmed cell death, is thought to play a role in the dichotomous behavior of neuroblastoma. We hypothesize that neuroblastoma cells will interact with host tissues to release mediators that affect apoptosis. MATERIALS AND METHODS: Human neuroblastoma cells and human Chang hepatocytes are grown in a noncontact, coculture system. After incubation for 4 days, the medium from the coculture system is collected. Neuroblastoma cells and Chang hepatocytes are then plated separately with the conditioned medium and their own standard growth medium as controls. After 4 days, these cells are harvested and cytospins made for immunostaining. Tumor necrosis factor alpha (TNF-alpha), Fas ligand, and Bcl-2, are measured with immunohistochemistry. Apoptosis is detected with the TUNEL method. Immunostaining data are interpreted with computer image analysis and reported as stain index. TUNEL data are reported as percentage apoptotic cells. All data are reported as means +/- SEM. Statistical analysis is performed and P < 0.05 considered significant. RESULTS: Chang hepatocytes grown in the coculture conditioned media have an increase in TNF-alpha and Fas ligand. The neuroblastoma cells have a significant decrease in Fas ligand. There is a significant increase in the number of apoptotic hepatocytes when they are cultured in the conditioned media. In contrast, the neuroblastoma cells grown in the coculture conditioned media show no increase in apoptosis. Finally, Bcl-2 is significantly increased in the neuroblastoma cells cultured in the conditioned media. CONCLUSIONS: Neuroblastoma cells grown in coculture conditioned media show increased expression of Bcl-2 and decreased Fas ligand levels. These changes should diminish apoptosis activity in the tumor cells. In contrast, the conditioned media induce elevated levels of proapoptotic mediators in the Chang hepatocytes. A tumor's ability to successfully metastasize may be dependent on mediators generated in the tumor-host interaction, and may not be just an independent characteristic of the tumor itself.

Fas-mediated induction of hepatocyte apoptosis in a neuroblastoma and hepatocyte coculture model.

BACKGROUND: We have previously demonstrated an increase in hepatocyte apoptosis when they are cocultured with neuroblastoma cells. Death receptors in the tumor necrosis factor (TNF) family such as TNFR1 and Fas have been identified as regulators of apoptosis and may be responsible for the altered regulation of apoptosis seen in our coculture model. To evaluate the effects of released factors and remove the potential alterations induced by direct contact, a noncontact coculture system was used to study the interaction between hepatocytes and neuroblastoma cells. METHODS: Human Chang hepatocytes (HC) were plated onto Falcon cell culture inserts with 0.45-micrometer pores in the permeable membrane. Human neuroblastoma cells (NB-IMR-32) were seeded into wells of the Falcon companion plate. After 24 h, inserts containing HC were placed into wells containing NB cells and incubated for 4 days. This provided a coculture environment without actual cellular contact. Immunohistochemical staining for TNFalpha, Fas, and Fas ligand (Fas-L) was performed. Apoptosis was detected via the TUNEL method. Images were analyzed with ImagePro-Plus. Statistical analyses were done with significance determined at P < 0.05. RESULTS: Chang hepatocytes demonstrated a significant increase in the levels of TNF, Fas, and Fas-L when cocultured with neuroblastoma cells (P < 0.005). In addition, the cocultured hepatocytes had a 20-fold increase in the apoptotic rate (P < 0.001). Neuroblastoma cells had no demonstrable level of Fas or TNF when grown alone and in cocultures. Neuroblastoma cells that were grown alone had an elevated level of Fas-L, but this level diminished by 44% when cocultured with hepatocytes (P < 0.001). CONCLUSION: An upregulated TNF/Fas receptor-ligand system may be responsible for increased apoptosis in hepatocytes when cocultured with neuroblastoma. This upregulation may be due to release of neuroblastoma-derived Fas ligand into the media. Tumors may alter the regulation of apoptosis in surrounding tissues via the death receptors.

Gastrointestinal perforation after pediatric orthotopic liver transplantation.

PURPOSE: The aim of this review was to determine the incidence of gastrointestinal perforation after pediatric liver transplantation and to identify risk factors and clinical indicators that may lead to an earlier diagnosis. METHODS: A retrospective chart review of all children who presented with gastrointestinal perforation after liver transplantation at our institution between January 1, 1987 and August 1, 1996 was performed. RESULTS: One hundred fifty-seven orthotopic liver transplants were performed in 128 children. Fifty-eight reexplorations, excluding those for retransplantation, were performed in 38 children. Ten perforations occurred in six children (incidence, 6.4%). Two children required multiple reexplorations because of several episodes of perforation. The sites of perforation were duodenum (n=1), jejunum (n=8), and ileum (n=1). A single-layer closure was used to repair five perforations, two-layer closures in four, and resection with primary anastomosis in another. The type of repair did not affect the occurrence of subsequent perforations. All the children were less than 18 months old. Four children had undergone prior laparotomy. All children had choledochoenteric anastomoses, but only one had a perforation associated with it. One child sustained bowel injury during the dissection for the liver transplant, but none of the perforations occurred at this site. Bowel function had returned before perforation in five children. Five children were receiving systemic antibiotics at the time of their perforation, and none had been dosed with pulse steroids for rejection. All of the children had significant changes in their temperature. Acute leukopenia developed in one child. A leukocytosis developed in the rest of the children. Abdominal radiographs demonstrated pneumoperitoneum in only one child. All children had positive culture findings from their abdominal drains. Cytomegalovirus developed in one child. Although the diagnosis of gastrointestinal perforation after pediatric liver transplant remains difficult, positive drain culture findings and significant alterations in temperature and leukocyte counts suggest its presence. Pneumoperitoneum is rarely present. CONCLUSION: A high index of suspicion and timely laparotomy, especially in children less than 2 years of age, may be the only way to rapidly diagnose and treat this potentially devastating complication of liver transplant.

Gastrointestinal surgery in cystic fibrosis.

This review is an attempt to summarize relevant gastrointestinal surgical issues in the patient with cystic fibrosis. Many of the surgical treatments are standard and have remained unchanged for several years and are only briefly discussed. A few areas with new developments are meconium ileus and the implications of prenatal diagnosis of meconium peritonitis. In addition, new findings with hepatobiliary disease and gastroesophageal reflux disease associated with cystic fibrosis patients may change the manner in which these entities are approached because these patients are now living longer. Finally, we review the recent findings associated with fibrosing colonopathy.

In utero lung growth of fetal sheep with diaphragmatic hernia and tracheal stenosis.

The observation that tracheal ligation produces pulmonary hyperplasia even in animals with surgically induced diaphragmatic hernia (DH) has led to rapid application of the technique to human fetuses with DH. The aim of this study was to determine how rapidly fetal lung volume increases after creation of a high-grade tracheal stenosis in fetal sheep with surgically created DH. Twenty-three fetal sheep were prepared with a left thoracotomy at 90 days' gestational. Six had creation of a DH with tracheal stenosis (DHTS) over an 18-gauge cannula, which was then removed. Ten had DH alone, and seven control animals (CT) had a thoracotomy without DH. Thirty days later, vascular and tracheal loop catheters were inserted in all animals and tunneled out the ewes' flank. Between 125 and 140 days' gestation, lung volumes and lung liquid production were measured in awake, unanesthetized animals using a standard double-marker dilution technique. Average lung volumes (in milliliters) were 150.9 +/- 13.9 for CT, 29.3 +/- 4.4 for DH, and 414.5 +/- 88 for DHTS (p < 0.01). Mean lung liquid production varied from 6.00 +/- 2.23 mL/h in DH animals before 130 days to 16.69 +/- 8.29 mL/h in DHTS animals after 135 days' gestation. DH animals had lower lung liquid production (8.51 +/- 1.4 mL/h) than CT (12.4 +/- 0.8 mL/h) or DHTS animals (12.4 +/- 2.2 mL/h)(P < .01). The rate constant gamma (h-1) for lung liquid production was significantly higher in DH animals than in either CT or DHTS animals (P < .01). Tracheal stenosis in this model causes rapid lung growth before 130 days' gestation. The authors speculate that short periods of incomplete stenosis might reverse the pulmonary hypoplasia associated with DH. To achieve this goal, the timing and duration of treatment and the optimal degree of stenosis must be defined.

Hepatic tumor necrosis factor-alpha production and distant organ dysfunction in a murine model of obstructive jaundice.

BACKGROUND: Multisystem organ dysfunction frequently occurs following obstructive jaundice, but its etiology remains unclear. This study was undertaken to evaluate the role for endogenous tumor necrosis factor-alpha (TNF-alpha) production in the renal and pulmonary injury that accompanies obstructive jaundice. METHODS: Two hundred and twenty C57BL/6 mice underwent ligation and division of the common bile duct or a sham celiotomy. The animals were randomized to receive either placebo or 1 mg/kg BW (low dose) or 15 mg/kg BW (high dose) of a novel TNF-alpha inhibitor comprised of two extracellular domains of the p55 TNF receptor linked together with polyethylene glycol. Serum bilirubin, creatinine, and urea nitrogen were determined. TNF-alpha bioactivity in plasma and organs was determined using the WEHI 164 clone 13 cytotoxicity assay. The TNF-alpha messenger RNA was detected by reverse transcriptase-polymerase chain reaction. Neutrophil infiltration into the lungs and kidney were quantitated by the myeloperoxidase assay. RESULTS: Common bile duct ligation and division resulted in rapid and sustained increases in serum bilirubin, creatinine, and urea nitrogen, peaking 2 to 5 days later. Hepatic TNF-alpha production was detected in the liver within 8 hours following obstructive jaundice, but TNF-alpha production could not be detected in the kidney or lung at any time point. Increased neutrophil infiltration occurred in the lung following obstructive jaundice peaking 5 days after obstructive jaundice. This neutrophil infiltration into the lungs could be partially inhibited (62%, P < 0.05) by administration of the novel TNF inhibitor. In contrast, neither renal nor hepatic dysfunction were affected by TNF-alpha blockade. CONCLUSIONS: Hepatic TNF-alpha production is an integral component of the response to obstructive jaundice. A TNF-alpha-mediated inflammatory response occurs in the lungs as a result of obstructive jaundice; however, renal and hepatic dysfunction do not appear to be TNF-alpha dependent since they cannot be affected by TNF-alpha blockade.

PEG-BP-30 monotherapy attenuates the cytokine-mediated inflammatory cascade in baboon Escherichia coli septic shock.

Septic shock following gram-negative infection is a leading cause of mortality in critically ill patients, accounting for nearly 200,000 deaths a year. The exaggerated production of tumor necrosis factor-alpha (TNF alpha) is known to contribute to hemodynamic collapse and the hematological dyscrasia associated with gram-negative sepsis. Although previous studies have shown TNF alpha antibodies and TNF immunoadhesins to be effective in experimental gram-negative sepsis, we postulated that administration of a novel construct of two modified soluble p55 receptors linked to polyethylene glycol (PEG-BP-30) would also attenuate the hemodynamic and hematologic alterations to lethal Escherichia coli septic shock in non-human primates. Nine adult female and male baboons (Papio anubis), weighing 10-17 kg, were anesthetized and invasively monitored. The nine animals were randomized to receive either 0.2 mg/kg body wt PEG-BP-30 (n = 3), 5.0 mg/kg body wt PEG-BP-30 (n = 3), or placebo (n = 3). One hour after pretreatment, animals were infused with 5-10 x 10(10) CFU/kg of live E. coli iv and vital signs were recorded for the next 8 hr. Arterial blood was drawn for baseline parameters and throughout the study to obtain total and differential white blood cell and platelet counts and cytokine levels (TNF alpha, IL-1 beta, IL-6, IL-8). E. coli bacteremic baboons receiving only placebo demonstrated a significant fall in mean blood pressure and leukopenia. Two of the three animals expired. In contrast, five of the six baboons receiving the PEG-BP-30 survived and these animals exhibited markedly attenuated declines in blood pressure and leukocyte numbers.(ABSTRACT TRUNCATED AT 250 WORDS)