The etiology and pathogenesis of bile duct obstruction in children with biliary atresia are largely unknown. We have previously reported that, despite phenotypic heterogeneity, genomic signatures of livers from patients display a proinflammatory phenotype. Here, we address the hypothesis that production of IFN-γ is a key pathogenic mechanism of disease using a mouse model of rotavirus-induced biliary atresia. We found that rotavirus infection of neonatal mice has a unique tropism to bile duct cells, and it triggers a hepatobiliary inflammation by IFN-γ-producing CD4 + and CD8 + lymphocytes. The inflammation is tissue specific, resulting in progressive jaundice, growth failure, and greater than 90% mortality due to obstruction of extrahepatic bile ducts. In this model, the genetic loss of IFN-γ did not alter the onset of jaundice, but it remarkably suppressed the tissue-specific targeting of T lymphocytes and completely prevented the inflammatory and fibrosing obstruction of extrahepatic bile ducts. As a consequence, jaundice resolved, and long-term survival improved to greater than 80%. Notably, administration of recombinant IFN-γ led to recurrence of bile duct obstruction following rotavirus infection of IFN-γ-deficient mice. Thus, IFN-γ-driven obstruction of bile ducts is a key pathogenic mechanism of disease and may constitute a therapeutic target to block disease progression in patients with biliary atresia.

We tested the role of different intracellular proteolytic pathways in sepsis-induced muscle proteolysis. Sepsis was induced in rats by cecal ligation and puncture; controls were sham operated. Total and myofibrillar proteolysis was determined in incubated extensor digitorum longus muscles as release of tyrosine and 3-methylhistidine, respectively. Lysosomal proteolysis was assessed by using the lysosomotropic agents NH4Cl, chloroquine, leupeptin, and methylamine. Ca2"-dependent proteolysis was determined in the absence or presence of Ca2" or by blocking the Ca2+-dependent proteases calpain I and II. Energy-dependent proteolysis was determined in muscles depleted of ATP by 2-deoxyglucose and 2.4-dinitrophenol. Muscle ubiquitin mRNA and the concentrations of free and conjugated ubiquitin were determined by Northern and Western blots, respectively, to assess the role of the ATP-ubiquitin-dependent proteolytic pathway. Total and myofibrillar protein breakdown was increased during sepsis by 50 and 440%, respectively. Lysosomal and Ca2"-dependent proteolysis was similar in control and septic rats. In contrast, energy-dependent total and myofibrillar protein breakdown was increased by 172% and more than fourfold, respectively, in septic muscle. Ubiquitin mRNA was increased severalfold in septic muscle. The results suggest that the increase in muscle proteolysis during sepsis is due to an increase in nonlysosomal energy-dependent protein breakdown, which may involve the ubiquitin system. (J. Clin. Invest. 1994. 94:2255-2264

Recent studies suggest that sepsis-induced increase in muscle proteolysis mainly reflects energy-ubiquitin-dependent protein breakdown. We tested the hypothesis that glucocorticoids activate the energy-ubiquitin-dependent proteolytic pathway in skeletal muscle during sepsis. Rats underwent induction of sepsis by cecal ligation and puncture or were sham-operated and muscle protein breakdown rates were measured 16 h later. The glucocorticoid receptor antagonist RU 38486 or vehicle was administered to groups of septic and sham-operated rats. In other experiments, dexamethasone (2.5 or 10 mg/kg) was injected subcutaneously in normal rats. Total and myofibrillar proteolysis was determined in incubated extensor digitorum longus muscles as release of tyrosine and 3-methylhistidine, respectively. Energydependent proteolysis was determined in incubated muscles depleted of energy with 2-deoxyglucose and 2,4-dinitrophenol. Levels of muscle ubiquitin mRNA and free and conjugated ubiquitin were determined by Northern and Western blot, respectively. RU 38486 inhibited the sepsis-induced increase in total and myofibrillar energy-dependent protein breakdown rates and blunted the increase in ubiquitin mRNA levels and free ubiquitin. Some, but not all, sepsisinduced changes in ubiquitin protein conjugates were inhibited by RU 38486. Injection of dexamethasone in normal rats increased energy-dependent proteolysis and ubiquitin mRNA levels. The results suggest that glucocorticoids regulate the energy-ubiquitin-dependent proteolytic pathway in skeletal muscle during sepsis.

Imaging is crucial in the assessment of children with a primary hepatic malignancy. Since its inception in 1992, the PRETEXT (PRE-Treatment EXTent of tumor) system has become the primary method of risk stratification for hepatoblastoma and pediatric hepatocellular carcinoma in numerous cooperative group trials across the world. The PRETEXT system is made of two components: the PRETEXT group and the annotation factors. The PRETEXT group describes the extent of tumor within the liver while the annotation factors help to describe associated features such as vascular involvement (either portal vein or hepatic vein/inferior vena cava), extrahepatic disease, multifocality, tumor rupture and metastatic disease (to both the lungs and lymph nodes). This manuscript is written by members of the Children's Oncology Group (COG) in North America, the International Childhood Liver Tumors Strategy Group (SIOPEL) in Europe, and the Japanese Study Group for Pediatric Liver Tumor (JPLT; now part of the Japan Children's Cancer Group) and represents an international consensus update to the 2005 PRETEXT definitions. These definitions will be used in the forthcoming Trial to Pediatric Hepatic International Tumor Trial (PHITT).

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Objective The goals of this study were to describe the clinical and anatomic features of infants undergoing Kasai portoenterostomy (KPE) for biliary atresia (BA), and to examine associations between these parameters and outcomes. Methods Infants enrolled in the prospective Childhood Liver Disease Research and Education Network, who underwent KPE were studied. Patients enrolled in a blinded, interventional trial were excluded from survival analysis. Primary end-points were successful surgical drainage (total bilirubin less than 2 mg/dL within the first three months), transplant-free survival (Kaplan-Meier), and time to transplant/death (Cox regression). Results KPE was performed in 244 infants (54% female; mean age 65± 29 days). Transplant-free survival was 53.7% and 46.7% at 1 and 2 years post-KPE. The risk of transplant/death was significantly lower in the 45.6% of patients who achieved successful bile drainage within 3 months post-KPE (HR 0.08, p<0.001). The risk of transplant/death was increased in patients with porta hepatis atresia (Ohi Type II and III vs. Type I; HR 2.03, p=0.030), non-patent common bile duct (Ohi Subtype b, c, and d vs. a; HR 4.31, p=0.022), BA splenic malformation syndrome (HR 1.92, p=0.025), ascites > 20 ml (HR=1.90, p=0.0230), nodular liver appearance compared to firm (HR=1.61, p=0.008), and age at KPE ≥ 75 days (HR 1.73, p<0.002). Outcome was not associated with gestational age, gender, race, ethnicity, or extent of porta hepatis dissection. Conclusion Anatomic pattern of BA, BASM, presence of ascites and nodular liver appearance at KPE, and early postoperative jaundice clearance are significant predictors of transplant-free survival.

Previous studies provided evidence that sepsis-induced muscle proteolysis in experimental animals is caused by increased ubiquitin-proteasome-dependent protein breakdown. It is not known if a similar mechanism accounts for muscle proteolysis in patients with sepsis. We determined mRNA levels for ubiquitin and the 20 S proteasome subunit HC3 by Northern blot analysis in muscle tissue from septic ( n ϭ 7) and non-septic ( n ϭ 11) patients. Plasma and muscle amino acid concentrations and concentrations in urine of 3-methylhistidine (3-MH), creatinine, and cortisol were measured at the time of surgery to assess the catabolic state of the patients. A three-to fourfold increase in mRNA levels for ubiquitin and HC3 was noted in muscle tissue from the septic patients concomitant with increased muscle levels of phenylalanine and 3-MH and reduced levels of glutamine. Total plasma amino acids were decreased by ‫ف‬ 30% in the septic patients. The 3-MH/creatinine ratio in urine was almost doubled in septic patients. The cortisol levels in urine were higher in septic than in control patients but this difference did not reach statistical significance. The results suggest that sepsis is associated with increased mRNAs of the ubiquitin-proteasome pathway in human skeletal muscle. ( J. Clin. Invest. 1997. 99:163-168.)

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