Human Pancreas Tissue Research Articles

Immunoperoxidase detection of pancreatic oncofetal antigen in human tissues

Normal human adult tissues (from the pancreas, stomach, small intestine, colon and rectum), human fetal pancreas and various human tumor tissues were investigated for the expression of pancreatic oncofetal antigen (POA) by the peroxidase-antiperoxidase complex method. The antibody used in this study was raised by immunization of rabbit with POA purified from ascites of a patient with pancreatic cancer; it was the same as in our previous report on enzyme immunoassay for serum POA. POA was localized in the ductal cells of human fetal pancreas and ductal cell type pancreatic cancer tissue. It was hardly seen in acinar cells of human fetal or adult pancreas, or in acinar cell type pancreatic cancer tissue. Several cancer tissues other than the pancreas revealed positive POA-staining but less frequently. POA was also detected in small amounts in the small duct of normal adult pancreas. In other normal human tissues, POA was recognized in deep crypts of the small intestine and colon. These results indicate that POA is present abundantly in immature ductal cells of the pancreas such as in fetal pancreas and pancreatic cancer, and that high serum levels of POA seen in patients with pancreatic cancer and other malignant tumors may originate from these malignant tissues.

Ultrastructural Changes of the Human Pancreas in Acute Shock

Human pancreas tissue was studied electron microscopically during various stages of shock. The subcellular changes of exocrine pancreas affect in particular endoplasmic reticulum (ER), mitochondria, cytoplasm, and nuclei. Alterations correlate with duration and severity of shock, causing cell death in prolonged or severe manifestations of shock. This is obviously due to release of enzymes from zymogen granules; the ensuing damage cannot be distinguished from autodigestive pancreatitis. Lesions of exocrine pancreas cells are of multifactorial origin, arising from general shock-induced hypoxia, but also from local ischemia due to disturbed microcirculation provoking intravasal coagulation. Beyond these main causes, intracellular disorders of metabolism, obstruction of lymph drainage, and nervous factors may be of influence. As the cases surveyed in this paper had no fatal outcome - except for one patient - the changes described can be defined as non-lethal or as reversible.

Immunocytochemical Distribution of Trypsinogen and Pancreatic Secretory Trypsin Inhibitor in Normal and Neoplastic Tissues in Man

Immunoreactive trypsinogen and pancreatic secretory trypsin inhibitor (PSTI) were demonstrated in pancreas by means of an immunoperoxidase technique. They had the same distribution in acinar cells of 'normal' human exocrine pancreas tissues. Ductal adenocarcinoma tissue and pancreatic undifferentiated carcinoma contained neither antigen. Scattered 'normal'-looking cells in the border area between normal and neoplastic tissue of both types of tumor stained positively for trypsinogen and for PSTI.

Expression of HLA-DR antigens in human fetal pancreas tissue.

The expression of HLA-DR antigens in human fetal pancreas tissue was studied using four independently derived monoclonal antibodies recognizing nonpolymorphic HLA-DR antigens. Immunoperoxidase staining of frozen sections revealed numerous DR-antigen-positive cells. Two major cell types could be distinguished. Large, strongly DR-positive cells with dendritic morphology were distributed throughout the dendritic morphology were distributed throughout the pancreatic parenchyma and interstitial connective tissue. Dual staining of DR antigens and insulin using a two-color immunoperoxidase technique clearly showed that some of these DR-positive dendritic cells were located within and in close association with insulin-producing islets. Also observed as a regular feature of fetal pancreas tissue sections were large clusters of DR-positive cells with lymphoid morphology. Positive staining of many cells within these clusters with monoclonal antibodies against T-cell marker (Leu-1) and T-cell subset markers (Leu-2 and -3) supported their classification as lymphoid cells. In contrast, no positive staining with anti-T-cell antibodies was observed outside of lymphoid cell clusters, confirming the distinction between these cells and the DR-positive cells distributed throughout the pancreas. The presence of other DR-bearing cell types in fetal pancreas could not be excluded, but most endothelial cells appeared to be DR-negative. The demonstration of numerous DR-bearing cells associated with fetal pancreas tissue may require that we alter our views on DR-antigen ontogeny and develop new strategies for fetal pancreas transplantation.

Human carboxypeptidase B. II. Purification of the enzyme from pancreatic tissue and comparison with the enzymes present in pancreatic secretion

Carboxypeptidase B (peptidyl- l-lysine(- l-arginine) hydrolase, EC 3.4.12.3) has been isolated and purified to apparent homogeneity from activated extracts of human pancreas tissue. The purified enzyme has been shown to be a single polypeptide of 34 000 daltons. In this respect the enzyme from pancreatic tissue, designated native human carboxypeptidase B, differs from the two forms present in human pancreatic juice (fractions I and II), both of which are composed of two polypeptides of approximately 24 000 and 9000 daltons. In addition, the three forms of human carboxypeptidase B differ in electrophoretic mobility in polyacrylamide gel electrophoresis and in chromatographic behavior on DEAE-cellulose. Two immunological methods, micro-complement fixation and radioimmunoassay, have shown a high degree of structural similarity between the three forms of human carboxypeptidase B. Micro-complement fixation experiments indicate that the amino acid sequences of the three enzymes differ by less than one percent. In vitro digestion studies have indicated that trypsin alone is sufficient to convert native carboxypeptidase B to carboxypeptidase B II. However, no combination of trypsin, chymotrypsin, and/or elastase was capable of converting native carboxypeptidase B to carboxypeptidase B I in vitro.