Islet cells

Hepoxylins are metabolites of arachidonic acid which arise from 12-HPETE in tissues such as pancreatic islet cells (where they stimulate glucose-dependent insulin release) and brain (where they appear to have a neuromodulatory role). The structure of the hepoxylins was confirmed by synthesis which also has provided this scarce material for biological investigation. 

OTRs are mainly expressed in myoepithelial cells of the galactiferus channels and the myometrium. The OTRs in vascular endothelial cells, renal epithelial cells (macula densa, proximal tubule) and cardiomyocytes induce the production of NO (vasodilation), natriuresis and release of ANP, respectively. The endometrium, ovary, amnion, testis, epididymis, prostate and thymus also express the OTR supporting a paracrine role of this peptide. Osteoblasts, osteoclasts, pancreatic islets cells, adipocytes, and several types of cancer cells also express OTRs. More over, expression of the OTR... 

In addition to the direct effects of hyperglycemia in enhancing the uptake of glucose into the liver, the hormone insulin plays a central role in regulating blood glucose. It is produced by the B cells of the islets of Langerhans in the pancreas in response to hyperglycemia. The B islet cells are freely permeable to glu-... 

Another condition involving ceruloplasmin is aceru-loplasminemia. in this genetic disorder, levels of ceruloplasmin are very low and consequently its ferroxidase activity is markedly deficient. This leads to failure of release of iron from cells, and iron accumulates in certain brain cells, hepatocytes, and pancreatic islet cells. Affected individuals show severe neurologic signs and have diabetes mellitus. Use of a chelating agent or administration of plasma or ceruloplasmin concentrate may be beneficial. 

Lamina II is also known as the substantia gelatinosa (SG) and can be divided into two layers, the outer layer (IIo) and the inner layer (Ili). This layer is densely packed with small neurons and lacks myelinated axons. Neurons with cell bodies in Hi receive inputs from low-threshold mechanoreceptive primary afferents, while those in IIo respond to inputs from high-threshold and thermoreceptive afferents. The intrinsic cells which comprise the SG are predominantly stalk and islet cells. Stalk cells are found located in lamina IIo, particularly on the border of lamina I, and most of their axons have ramifications in lamina I although some also project to deeper layers. These cells are thought to predominantly relay excitatory transmission. Islet cells, on the other hand, are located in Hi and have been demonstrated to contain the inhibitory neurotransmitters, y-aminobutyric acid (GABA), glycine and enkephalins in their dendrites. Hence these cells have been proposed to be inhibitory interneurons. 

Free Radicals and Islet Cells in Diabetes 187 Damage in Diabetes Involving ... 

CF-related diabetes shares characteristics of both type 1 and type 2 diabetes mellitus but is categorized separately. The primary cause of CFRD is insulin deficiency resulting from both reduced functional pancreatic islet cells and increased islet amyloid deposition. Insulin secretion is delayed in response to glucose challenge, and absolute insulin secretion over time is reduced. Some insulin resistance may also be present in CFRD however, sensitivity may be increased in CF patients without diabetes.8... 

Transplant of a pancreas may involve either the entire organ or a pancreas segment. Currently, whole-organ transplant is the most common procedure, with a portion of the duodenum often transplanted along with the pancreas. Living donors are often the source of segmental transplants. In recent years, isolation and transplantation of beta islet cells alone have been completed, although at the time of this publication this procedure is still considered experimental. 

Petrik J, Pell JM, Arany E et al 1999 Overexpression of insulin-like growth factor-II in transgenic mice is associated with pancreatic islet cell hyperplasia. Endocrinology 140 2353-2363... 

Fig. 8 Immobilization of urokinase on the surfaces of islet cells, (a) Surface modification (/) chemical structure of ssDNA-PEG-lipid, and (2) ssDNA-PEG-lipid anchoring to the cell membrane. (b) Introduction of a complementary ssDNA onto urokinase, which was first modified with a madeimide group by a cross-linker, EMCS. (c) Urokinase-immobilization through DNA...

Moberg L, Johansson H, Lukinius A et al (2002) Production of tissue factor by pancreatic islet cells as a trigger of detrimental thrombotic reactions in clinical islet transplantation. Lancet 360 2039-2045... 

Altman JJ, Legrelle M, Penformis A, Mallegol S, Fakir M, Chapa O, Capron F (1992) In Ricordi C (ed) Pancreatic islet cell transplantation. RG Landes, Austin, TX, p 215... 

Diabetes Death of pancreatic islet cells induces insulin resistance... 

Systemic effects of nickel exposure include hyperglycemia, increased levels of plasma glucagon, damage to the pancreatic islet cells, decreased body weight, reduced food and water intake, and hypothermia (NAS 1975 USEPA 1980 USPHS 1993). Acute administration of nickel salts caused prompt hyperglucagonemia and subsequent hyperinsulinemia in rats, rabbits, and guinea pigs (WHO... 

Three examples will show how freezing processes can be studied quantitatively and documented using this microscope system. Figure 1.39 shows the change in volume of an isolated islet cell of a mouse as a function of temperature. The different permeability of cell membranes for HzO and CPAs are important for freezing of cell, as Fig. 1.40 shows. 

Fig. 1.39. Volume change as a function of temperature of an isolated islet cell of a mouse (Fig. 4 from LI.28]).

To date, cellular and gene therapy products submitted to FDA have included clinical studies indicated for bone marrow marking, cancer, cystic fibrosis, AIDS, and inborn errors of metabolism and infectious diseases. Of the current active INDs approximately 78% have been sponsored by individual investigators or academic institutions and 22% have also been industry sponsored. In addition to the variety of clinical indications the cell types have also been varied. Examples include tumor infiltrating lymphocytes (TIL) and lymphocyte activated killer (LAK) cells, selected cells from bone marrow and peripheral blood lymphocytes, for example, stem cells, myoblasts, tumor cells and encapsulated cells (e.g., islet cells and adrenal chromaffin cells). 

Manipulation. Autologous, allogenic, or xenogenic cells which have been expanded propagated manipulated or had their biological characteristics altered ex vivo (e.g., TIL or LAK cells islet cells housed in a membrane). 

Pancreatic islet-cell neoplasia in rats Harderian-gland neoplasia in mice... 

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