--Disease Characteristics-- Severely premature neonates (less than 1000 g at birth and estimated gestational age of no greater than 28 weeks) that require greater than 50% of caloric requirements by parenteral means within 7 days of birth OR Neonates with one or more of the following surgical conditions: Necrotizing enterocolitis Gastroschisis Severe jejunal-ileal atresia within 7 days of diagnosis --Prior/Concurrent Therapy-- Biologic therapy: Not specified Chemotherapy: Not specified Endocrine therapy: Not specified Radiotherapy: Not specified Surgery: See Disease Characteristics No other cardiovascular (thoracotomy) or major gastrointestinal surgery (laparotomy) during the newborn period Other: No prior or concurrent ursodeoxycholic acid No concurrent use of extracorporeal life support --Patient Characteristics-- Performance status: Not specified Hematopoietic: Not specified Hepatic: Conjugated bilirubin no greater than 1.0 mg/dL No primary or secondary liver disease No hepatic insufficiency as documented by either a biopsy with cirrhosis or elevated prothrombin time without evidence of systemic coagulopathy and no administration of an anticoagulant Renal: No renal failure as indicated by a progressive increase in creatinine levels Other: No hemodynamic instability No documented communicable infection (including infectious hepatitis or HIV) No metabolic pathway defect that is associated with liver dysfunction in the neonatal period including hereditary fructose intolerance, galactosemia due to transferase deficiency, and neonatal tyrosinemia