A major avenue of our research has been to develop molecular probes (cDNAs) for studying the pathogenesis of liver disease (i.e., applied molecular pathophysiology). During the last 2-3 yr, we have developed and used molecular hybridization to study regulation of albumin synthesis in normal, protein-calorie deprived, uremic, and cirrhotic rat liver. Our current work is directed toward cloning the albumin gene to permit further analysis of albumin transcriptional and posttranscriptional control. Molecular hybridization, DNA cloning, related techniques can be utilized to study the function of virtually any gene. Incorporation of such advances in basic research into meaningful studies of liver disease is an exciting challenge to modern academic hepatology.

We report a case of an anticoagulated patient presenting with a massive upper gastrointestinal hemorrhage, abdominal pain, and a palpable abdominal mass, demonstrated to be an intramural hematoma of the jejunum. Approximately two-thirds of intramural hematomas of the small intestine are preceded by abdominal trauma with the remainder associated with pancreatic disease, alcoholism, unknown causes, or clotting defects. Spontaneous occurrence of intramural hemorrhage is uncommon. Of the varied clinical presentations, gastrointestinal bleeding, previously thought unusual, is seen in 30% of cases, although major hemorrhage is rare. Conversely, reports of intramural hematoma of the small intestine as a case of major gastrointestinal bleeding has not been recognized. A review of the literature follows, and the authors stress that abdominal trauma should raise the possibility of an intramural hematoma of the small bowel.

The intestinal epithelium is intimately associated with immunoglobulins. This association may begin in neonatal life with the ingestion of large quantities of immunoglobulins in breast fluids. These ingested immunoglobulins probably have a local protective action in the intestinal lumen. In some mammalian species a large portion of the maternal immunoglobulins is translocated intact across the intestinal epithelium into the circulation, providing additional immunological protection. In rodents, the transepithelial translocation of IgG from breast fluids is initiated and critically dependent upon receptors on enterocyte surface membranes for the Fc region of IgG. Close epithelial-immunoglobulin relationships continue throughout life with the transfer of various classes of immunoglobulins across the epithelium into the intestinal fluids. In man and other mammalian species, IgA and IgM are selectively transported through enterocytes, principally in the crypts of intestinal glands. This transfer may involve binding of polymeric forms of these immunoglobulins to receptors on the abluminal surfaces of the enterocytes. The secretory component, a glycoprotein synthesized by enterocytes, may be such a receptor. IgE and IgG enter the gut lumen by mechanisms that are not defined but seem to be distinct from those involved in the translocation of IgA and IgM. Secreted antibodies in intestinal fluids and mucus bathe the luminal surfaces of intestinal epithelial cells but appear not to be firmly bound to their apical plasma membranes or glycocalyces. The intimate association of immunoglobulins with intestinal epithelial cells illustrates the close relationships that exist between the gut and lymphoid cells and their products. These relationships suggest the possibility that the gut epithelium is affected by a large variety of immunological reactions in health and disease; these possibilities, which have been explored only minimally, warrant much attention in the future. Studies on the binding, uptake, and intracellular transport of immunoglobulins by enterocytes could contribute much to the understanding of receptors for immunoglobulins on many other types of cells, such as lymphocytes, macrophages, mast cells, and the lining cells of placental or yolk sac membranes.

An unusual case of biliary obstruction caused by a benign villous adenoma of the ampulla of Vater is reported and the literature reviewed. Of the reported cases, 75% have jaundice or symptoms of cholecystitis. Rarely, gastrointestinal bleeding or pancreatic duct obstruction is a presenting symptom. The tumors are frequently small and can be overlooked. Operative treatment varies from excision of the tumor to pancreatoduodenal resection depending on histological evaluation, intraoperative findings, and the surgeon's philosophy.

This review deals with the types of gastrointestinal polyposis in which genetic factors play an essential part, namely, the hamartomatous lesions of Peutz-Jeghers syndrome and multiple juvenile polyposis and the neoplastic tumors of familial polyposis coli and multiple adenomas. The mode of inheritance, associated lesions, malignancy potential, and possible interrelationships between the various types of polyposis are discussed. The knowledge that the lesions are inherited should enable other family members to be investigated and treated at an early stage, a matter of considerable importance in the prevention of cancer when there is an associated risk of gastrointestinal carcinoma.

A case of carcinoma arising in a congenitally dilated biliary tract is reported. Forty-seven cases in which congenital dilatation of the biliary tract was associated with carcinoma were found in the world literature and analyzed. The association of carcinoma with congenital biliary ductal dilatation was found to be higher than previously recognized. Carcinoma may arise in any cystic portion, extrahepatic or intrahepatic. If technically safe and feasible, primary excision of the choledochal cyst is advisable, to prevent the risk of later malignant change in the unexcised cyst.