• Patients with pancreatic neoplasms that have the histologic characteristics of a pancreatic endocrine tumor but no associated elevation in plasma hormone levels (excluding the pancreatic polypeptide level) and those without a recognizable clinical syndrome are considered to have nonfunctional pancreatic endocrine tumors. (medscape.com)
  • Pancreatic polypeptide (PP) is a product that appears to be a marker for pancreatic endocrine tumors, but it is not a mediator of any specific PP-related clinical syndrome. (medscape.com)
  • [ 11 ] Other nonfunctional pancreatic endocrine tumors likely secrete unknown products that are of little or no clinical significance. (medscape.com)
  • [ 13 ] APUD cells were once believed to originate from the embryologic neural crest, but current evidence suggests that these cells-and thus endocrine tumors of the pancreas and other endocrine tumors of the upper gastrointestinal tract (eg, carcinoid tumors)-actually develop from the embryologic endoderm. (medscape.com)
  • Although the term islet cell tumor is often used to identify neoplasms of the endocrine pancreas, this is a misnomer because many pancreatic neuroendocrine tumors do not develop directly from islet cells. (medscape.com)
  • [ 15 ] Instead, the tumors arise from APUD stem cells, which are pluripotential neuroendocrine cells located within the ductular epithelium of the exocrine pancreas and elsewhere in the distal foregut. (medscape.com)
  • Functional pancreatic endocrine neoplasms cause physiologic derangements related to the normal action of the hormonal product that the tumors overproduce. (medscape.com)
  • They may manifest as sporadic tumors or as part of certain syndromes, including multiple endocrine neoplasia type 1 (MEN 1) and von Hippel-Lindau (VHL) disease. (medscape.com)
  • Although nonfunctional islet cell tumors are not uncommon at autopsy, most islet cell tumors with clinical manifestations are functional. (medscape.com)
  • Pancreatic islet cell tumors may secrete 2 or more polypeptide hormones. (medscape.com)
  • Islet cell tumors in this group are often multiple and malignant. (medscape.com)
  • This article reviews the role of imaging in the management of islet cell tumors. (medscape.com)
  • No universally agreed-upon algorithm exists in the radiologic investigation of pancratic neuroendocrine (islet cell) tumors of the pancreas. (medscape.com)
  • Evidence has shown that endoscopic ultrasonography (EUS) can be used to accurately diagnose and localize primary endocrine tumors of the pancreas, especially insulinomas and gastrinomas. (medscape.com)
  • The current neuroendocrine classification of cells and tumors uses immunohistochemical (IHC), ultrastructural, and molecular biologic features to define members of the DNS ( 6 , 7 and 8 ). (basicmedicalkey.com)
  • Carcinoid tumors arise from neuroendocrine cells, which are widespread in the human body, especially in the organs derived from the primitive intestine. (medscape.com)
  • [ 4 ] but Oberndorfer called a group of small, benign-appearing tumors karzinoide tumoren (carcinoid) for the first time in 1907. (medscape.com)
  • In 1914, Gosset and Masson demonstrated that carcinoid tumors might arise from enterochromaffin cells (Kulchitsky cell) within glands of Lieberkühn using silver impregnation techniques. (medscape.com)
  • In 1928, Masson established characterization of carcinoids as argentaffin cell tumors. (medscape.com)
  • In 1980, the World Health Organization (WHO) applied the term carcinoid to all tumors of the diffuse endocrine system (synonymous with amine precursor uptake and decarboxylation [APUD] and neuroendocrine cell system). (medscape.com)
  • however, tumors can originate from any cell of the amine precursor uptake and decarboxylation system and, therefore, produce several intestinal hormones. (medscape.com)
  • Carcinoid tumors and related syndromes may be a part of multiple endocrine neoplasia . (medscape.com)
  • The cells in pancreatic endocrine neoplasms are termed amine precursor uptake and decarboxylation (APUD) cells because they have a high amine content, are capable of amine precursor uptake, and contain an amino acid decarboxylase. (medscape.com)
  • Islet cells commonly are referred to as APUD cells, a name derived from their high amine content and capacity for amine precursor uptake with decarboxylation. (medscape.com)
  • The detailed study of neuroendocrine cells by Pearse ( 3 , 4 ) led to the development of the concept of amine precursor uptake and decarboxylation (APUD). (basicmedicalkey.com)
  • The first report of a hormone-producing pancreatic tumor syndrome was published in 1927, when Wilder et al described insulinoma syndrome in a patient with a metastatic islet cell tumor who had hyperinsulinism and hypoglycemia. (medscape.com)
  • [ 2 ] Subsequently, four other classic pancreatic endocrine tumor syndromes have been described. (medscape.com)
  • Clinical features of the syndrome depend on tumor cell type. (medscape.com)
  • APUD cells (DNES cells) constitute a group of apparently unrelated endocrine cells, which were named by the scientist A.G.E. Pearse, who developed the APUD concept in the 1960s based on calcitonin-secreting parafollicular C cells of dog thyroid. (wikipedia.org)
  • [ 12 ] Pearse first used the term APUD in 1968 to unify a group of functionally and structurally similar neuroendocrine cells that are present throughout the body. (medscape.com)
  • Although the APUD concept provided a unifying theory for explaining some endocrine diseases and ectopic hormone productions, the hypothesis that the cells were all of neural crest origin, as postulated by Pearse, was later disproved by the experiments of LeDouarin ( 5 ) and others. (basicmedicalkey.com)
  • Several other rare clinical syndromes have been proposed as possible functional endocrine syndromes associated with pancreatic neoplasms. (medscape.com)
  • Neoplasms of the endocrine pancreas can be divided into functional and nonfunctional varieties. (medscape.com)
  • Furthermore, the sudden increase in gastric acid secretion following a meal can causes a physiological phenomenon called the alkaline tide , which is due to the production and export of bicarbonate from parietal cells. (wikidoc.org)
  • In pancreatic islets, GLUT2 allows a rapid equilibration of glucose between the extracellular space and the interior of the cells and it may play a crucial role in the glucose signaling mechanism leading to insulin secretion (43). (justia.com)
  • Most pancreatic endocrine neoplasms discovered clinically are functional-that is, they secrete one or more hormonal products into the blood, which leads to a recognizable clinical syndrome. (medscape.com)
  • Parietal cells (also called oxyntic cells ) are the stomach epithelium cells which secrete gastric acid and intrinsic factor . (wikidoc.org)
  • The cells and neoplasms of the neuroendocrine and paracrine systems make up the DNS. (basicmedicalkey.com)
  • The principal cells and neoplasms that form the DNS are listed in Table 11.1 . (basicmedicalkey.com)
  • Pancreatic islet cells are part of the diffuse neuroendocrine system of the gut and pancreatic endocrine system. (medscape.com)
  • insulin-secreting cells, the basolateral membrane of intestinal and kidney absorptive cells, in hepatocytes and in a subset of neurons (21,31,44). (justia.com)
  • Hydrogen ions are pumped out of the cell into the canaliculi in exchange for potassium ions, via the H + /K + ATPase . (wikidoc.org)
  • These cells share the common function of secreting a low molecular weight polypeptide hormone. (wikipedia.org)
  • On the other hand, insulinoma cells that had lost their normal glucose responsiveness have low GLUT2 content, but some glucose sensitivity may be recovered after reintroducing GLUT2 expression through stable transfection of these cells (10,16). (justia.com)
  • The steroid-producing endocrine cells of the adrenal cortex, ovary, and testis, as well as the thyroid hormone-producing follicular cells in the thyroid gland, do not form part of the DNS. (basicmedicalkey.com)
  • Paracrine regulation refers to the production of amines and hormones by cells that exert a local effect on the target cells by diffusion through the extracellular space. (basicmedicalkey.com)
  • The production of somatostatin by the pancreatic islets, which regulates insulin and glucagon production in neighboring islet cells, is an example of paracrine regulation. (basicmedicalkey.com)
  • The use of radiolabeled octreotide to target radiation treatment toward a VIPoma is based on the affinity of octreotide for the somatostatin receptors on the VIPoma cells. (medscape.com)
  • A fragment of the murine GLUT2 promoter has been cloned and shown to be glucose-responsive when transfected into differentiated insulin-producing cells or into hepatocytes (35,36,52). (justia.com)
  • These cells share the ability to produce many biologically active amines, peptides, and other substances. (basicmedicalkey.com)
  • Adenohypophysis Neurons of Hypothalamus Chief Cells of Parathyroid Adrenal Medullary Cells Glomus cells in Carotid Body Melanocytes of Skin Cells of Pineal Gland Renin producing cells in the kidney Apudoma Enteroendocrine cell Neuroendocrine cell List of human cell types derived from the germ layers Boyd, C. A. R. (March 2001). (wikipedia.org)
  • This increases intracellular cyclic AMP , which leads to activation of protein kinase A. Protein kinase A phosphorylates proteins involved in the transport of H + /K + ATPase from the cytoplasm to the cell membrane . (wikidoc.org)
  • The DNS consists of a wide variety of cells that are present in the central and peripheral nervous system and in many classic endocrine organs ( Table 11.1 ). (basicmedicalkey.com)
  • These are a group of conditions with onset in the developmental period. (edu.au)
  • High risk of acute pulmonary toxicity with both myeloablative and non-myeloablative total body irradiation-based conditioning for allogeneic stem cell transplantation. (dukecancerinstitute.org)
  • Nodules are composed of irregularly large cells and sparse colloid. (teknon.es)
  • Parietal cells produce gastric acid ( hydrochloric acid ) in response to histamine (via H 2 receptors ), acetylcholine (M 3 receptors) and gastrin (CCK2 receptors). (wikidoc.org)
  • Parietal cells also produce intrinsic factor . (wikidoc.org)
  • The damaged parietal cells are unable to produce the required amount of gastric acid. (wikidoc.org)
  • Parietal cells contain an extensive secretory network (called canaliculi) from which the HCl is secreted by active transport into the stomach. (wikidoc.org)
  • In these cells, GLUT2 catalyzes the transepithelial transport of glucose. (justia.com)