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The technique of thoracoscopy has been performed on 49 occasions in 45 patients for the diagnosis or staging of intrathoracic tumors. The patients ranged from 8 months to 68 years old. Eight procedures were performed for pleural disease, 16 for mediastinal masses, 22 for parenchymal lesions, and 3 for intrathoracic staging. Seventeen patients had had previous invasive procedures performed without a pathological diagnosis being established. In 28 thoracoscopy procedures, a positive diagnosis for malignancy was obtained; in 6 instances, areas of unsuspected tumor involvement were identified. A correct diagnosis was obtained by thoracoscopy in 45 procedures for a 92% overall accuracy rate. There was no clinically significant morbidity in this series and no procedure-related mortality. Thoracoscopy, performed under stellate ganglion block and regional anesthesia, has proved to be a very attractive method of diagnosing intrathoracic neoplasia with very low morbidity.

Alimentary tract duplications are rare anomalies that present with a wide spectrum of clinical manifestations. Mass lesions or obstructive symptoms predominate in infancy, while pain and hemorrhagic complications often herald their recognition in childhood. Spontaneous perforation, a rarely encountered complication, accounted for the acute exacerbation of previously chronic abdominal pain in a three-year-old girl. This case emphasizes the potential for these benign lesions to present with progressive abdominal symptoms and ultimately pressure-induced ischemic perforation.

Obstructive jaundice in infancy and childhood can arise from a variety of causes. Recognition of the importance of persistent jaundice beyond 2 weeks of age in the infant or elevation of the conjugated bilirubin more than 2 mg/dl will allow the timely evaluation of neonates with possible biliary atresia prior to the development of irreversible hepatic damage. Episodes of intermittent jaundice or persistent conjugated hyperbilirubinemia should be investigated at any age to exclude obstructive lesions of the extrahepatic biliary tract. In all cases, a rapid but carefully coordinated evaluation can be undertaken by a pediatric gastroenterology and surgical team, allowing optimum economy of effort and preservation of hepatic function. In nearly all cases with obstructive lesions of the extrahepatic biliary tree, satisfactory hepatic function can be preserved through appropriate surgical intervention. Results with biliary atresia continue to improve but are dependent on early diagnosis and treatment. In cases in which hepatic function deteriorates and hepatic failure becomes inevitable, orthotopic hepatic transplantation can be lifesaving and should be undertaken prior to the onset of irreversible hepatic decompensation. Although the terminology may be somewhat confusing and its etiology uncertain, the entity of choledochal cysts, taken within the context of its modern classification, accurately describes a group of cystic anomalies of the extrahepatic (and intrahepatic) biliary tree, which have many common features. The vast majority can be expeditiously dealt with by surgical excision and hepaticoenteral reconstruction. Two particular associations with choledochal cysts are important to note. When it occurs with infancy, choledochal cysts can be difficult to diagnose, but very important to define and treat expeditiously in order to prevent serious impairment of hepatic function. In all patients, but particularly in adults, the risk of associated carcinoma necessitates extremely careful definition of the biliary tree and urges one to advocate complete excision of the cyst at initial operation.

Peptic stricture of the esophagus and achalasia both cause dysphagia. They are not always readily distinguished by history. The usual workup with upper gastrointestinal x ray and endoscopy may also fail to differentiate the two disorders. Two cases are presented wherein antireflux procedures were mistakenly performed when achalasia was present rather than peptic stricture. Dysphagia was unrelieved and extensive further procedures were required. In a third patient referred for a peptic stricture, manometry revealed the correct diagnosis and heller myotomy provided relief. It is recommended that manometry be performed as a part of the preoperative workup in patients in whom there is any element of dysphagia.

Transport of taurocholate into the hepatocyte against unfavorable chemical and electrical gradients occurs via a sodium-dependent, carrier-mediated transport system. Although this cotransporter has been characterized in the rodent, it has not been demonstrated in man. Therefore, we utilized human liver, obtained via multiorgan donation but not used for transplantation, to prepare basolateral (sinusoidal) liver plasma membrane vesicles by a Percoll gradient method. Na+,K+-ATPase, a marker enzyme for the basolateral domain, was enriched 28.9-fold in the final membrane fraction compared with homogenate, whereas the bile canalicular membrane enzymes Mg++-ATPase and alkaline phosphatase were enriched only 3.4- and 6.4-fold, respectively. Marker enzyme activities for endoplasmic reticulum, lysosomes and mitochondria were not enriched compared with homogenate. Integrity of the membrane vesicles was confirmed by the demonstration of Na+-dependent concentrative uptake of the amino acid L-alanine (estimated intravesicular volume of 0.59 microliter per mg protein). An inwardly directed 100 mM Na+ gradient stimulated the initial rate of 2.5 microM taurocholate uptake and energized a transient 2-fold accumulation of the bile acid above equilibrium ("overshoot"). In contrast, uptake was slower and no overshoot occurred with a K+ gradient. A negative intravesicular potential, created by altering accompanying anions or by valinomycin-induced K+ diffusion potentials, did not enhance taurocholate uptake, suggesting an electroneutral cotransport mechanism. Chloride as the accompanying anion stimulated the initial rate of uptake compared with anions of lesser or greater lipid permeability. Na+-dependent taurocholate (4 microM) uptake was significantly inhibited by 250 microM cholate, taurocholate, glycocholate, taurochenodeoxycholate and bromsulfophthalein.(ABSTRACT TRUNCATED AT 250 WORDS)

Continuous hemofiltration (CH) for the treatment of hypervolemia and electrolyte abnormalities in critically ill patients with acute renal failure has been shown to be an effective mode of therapy. This technique offers several advantages over peritoneal dialysis or hemodialysis: it is technically less complex, provides efficient ultrafiltration, and produces fewer hemodynamic disturbances. Recently, continuous hemodiafiltration (CHD) using a flow of dialysate fluid into the ultrafiltration chamber has been reported to augment urea clearance. The purpose of this study was to determine the blood flow and dialysate flow characteristics for optimal clearance of urea and creatinine using this technique. Six mongrel dogs (mean weight, 8.0 +/- 1.1 kg) underwent bilateral nephrectomy to induce anuric renal failure. Postoperatively, the animals were fluid resuscitated and fed ad libitum. Twenty-four hours following nephrectomy, venovenous hemofiltration was instituted. Blood flow was regulated via a roller pump, while dialysate flow was regulated using an infusion controller. An Amicon-30S hemofilter was used in the circuit. Blood flow rates of 5, 10, 15, 20, 25, and 30 mL/kg/min were used. Hemodiafiltration using Dianeal 1.5% solution was used in each animal. Net fluid losses via ultrafiltration were replaced using lactated Ringer's solution. Three of six animals survived for the complete five-hour hemofiltration period. No marked disturbances in electrolyte serum concentrations, including hyperkalemia, were observed. BUN concentrations were reduced by 35% and creatinine by 26%. Variation of the dialysate flow rate did not influence clearance of either urea or creatinine. Instead, clearance appeared to be flow dependent, and it was markedly increased at flow rates greater than 15 mL/kg/min.(ABSTRACT TRUNCATED AT 250 WORDS)