Search results for "Islet"
showing 8 items of 98 documents
Transient chylomicronemia preceding the onset of insulin-dependent diabetes in a young girl with no humoral markers of islet autoimmunity
2004
OBJECTIVE: We investigated the possible causes of diabetes in a young child who presented with hyperglycemia associated with severe hypertriglyceridemia (>166 mmol/l), hypercholesterolemia (>38 mmol/l) and fasting chilomicrons. RESULTS: The patient did not have any of the HLA and autoantibody markers typically associated with type 1 diabetes. A glucose clamp failed to demonstrate insulin resistance (peripheral glucose utilization rate (M)=4.3 mg/kg per min) and there was no family history of type 2 diabetes or maturity onset diabetes in youth. Both fasting and stimulated C-peptide levels, including those in response to i.v. glucagon, were below the limit of detection. This is consiste…
Islet beta-cell apoptosis triggered in vivo by interleukin-1beta is not related to the inducible nitric oxide synthase pathway: evidence for mitochon…
2003
IL-1beta is recognized as an effector cytokine contributing to islet beta-cell destruction during diabetes. We have previously shown in vitro that IL-1beta induces nitric oxide (NO) and beta-cell damage. Here, we show that IL-1beta administration in vivo to Wistar rats transiently increases manganese superoxide dismutase activity, whereas inducible NO synthase is not detected, and the levels of nitrate+nitrate do not change. Moreover, a significant decrease of mitochondrial aconitase, leading to a rise of hydroperoxides, and islet beta-cell apoptosis, involving caspase-3 and -8, is observed. Analysis of adhesion molecules in beta-cells showed that intercellular adhesion molecule-1 is highly…
Glucose homeostasis is impaired in mice deficient for the neuropeptide 26RFa (QRFP)
2019
AbstractIntroduction26RFa (QRFP) is a biologically active peptide that has been found to control feeding behaviour by stimulating food intake, and to regulate glucose homeostasis by acting as an incretin. The aim of the present study was thus to investigate the impact of 26RFa gene knockout on the regulation of energy and glucose metabolism.Research design and methods26RFa mutant mice were generated by homologous recombination, in which the entire coding region of prepro-26RFa was replaced by the iCre sequence. Energy and glucose metabolism was evaluated through measurement of complementary parameters. Morphological and physiological alterations of the pancreatic islets were also investigat…
In Vivo Molecular Imaging of Somatostatin Receptors in Pancreatic Islet Cells and Neuroendocrine Tumors by Miniaturized Confocal Laser-Scanning Fluor…
2010
The aim of the study was to evaluate real time in vivo molecular imaging of somatostatin receptors (sstrs) using a handheld miniaturized confocal laser scan microscope (CLM) in conjunction with fluorescein-labeled octreotate (OcF) in healthy mice and murine models of neuroendocrine tumors. For CLM a small rigid probe (diameter 7 mm) with an integrated single line laser (488 nm) was used (optical slice thickness 7 μm; lateral resolution 0.7 μm). OcF was synthesized via Fmoc solid-phase peptide synthesis and purified by HPLC showing high-affinity binding to the sstr2 (IC50 6.2 nmol). For in vitro evaluation, rat and human pancreatic cancer cells were used and characterized with respect to its…
Synthesis and in vitro evaluation of (S)-2-([11C]methoxy)-4-[3-methyl-1-(2-piperidine-1-yl-phenyl)-butyl-carbamoyl]-benzoic acid ([11C]methoxy-repagl…
2004
The 11 C-labeled sulfonylurea receptor 1 (SUR1) ligand (S)-2-(( 11 C)methoxy)-4-(3-methyl-1-(2-piperidine-1-yl-phenyl)- butyl-carbamoyl)-benzoic acid (( 11 C)methoxy-repaglinide) was synthesized in an overall radiochemical yield of 35% after 55 min with a radiochemical purity higher than 99%. This compound is considered for the noninvasive investigation of the SUR1 receptor status of pancreatic b-cells by positron emission tomography (PET) in the context of type 1 and type 2 diabetes. The specific activity was 40-70 GBq/lmol. In vitro testing of the nonradioactive methoxy-repaglinide was performed to characterize the affinity for binding to the human SUR1 isoform. Methoxy-repaglinide induce…
VIPoma and PPoma
2015
Gastrinomas are rare tumors of the neuroendocrine system, occurring within the pancreas and duodenum. The annual incidence is estimated at 0.5 per million of the population [1]. Overproduction of gastrin by these tumors produces a sustained increase in gastric acid secretion, leading to clinical manifestations of complicated peptic ulcer disease known as the Zollinger-Ellison syndrome (ZES) [2]. Although most gastrinomas grow slowly, over 60 % are malignant and 25 % show rapid aggressive behavior [3-5]. Most commonly gastrinomas metastasize to regional lymph nodes and the liver, and it is this malignant potential which has become increasingly important since the introduction of effective me…
Localization of small islet-cell tumors. Preoperative and intraoperative ultrasound, computed tomography, arteriography, digital subtraction angiogra…
1985
A total of 42 islet-cell tumors were examined between 1972 and 1984. Problems of localization were only encountered in 31 tumors less than 2 cm in diameter. Of 31 small tumors, 27 were correctly localized using a combined diagnostic approach: ultrasound was successful in 12/20 tumors, CT in 9/21, angiography in 20/31, intraarterial digital subtraction angiography in 1/2, and pancreatic venous sampling in 13/16. The smallest tumor found by ultrasound and CT was 7 mm in diameter. Intraoperative ultrasound demonstrated all 9 insulinomas examined. Currently, the most useful techniques for localizing small islet-cell tumors are ultrasound, CT, and angiography. CT is particularly useful for tumor…
Increased dosage of Ink4/Arf protects against glucose intolerance and insulin resistance associated with aging
2013
Recent genome-wide association studies have linked type-2 diabetes mellitus to a genomic region in chromosome 9p21 near the Ink4/Arf locus, which encodes tumor suppressors that are up-regulated in a variety of mammalian organs during aging. However, it is unclear whether the susceptibility to type-2 diabetes is associated with altered expression of the Ink4/Arf locus. In the present study, we investigated the role of Ink4/Arf in age-dependent alterations of insulin and glucose homeostasis using Super-Ink4/Arf mice which bear an extra copy of the entire Ink4/Arf locus. We find that, in contrast to age-matched wild-type controls, Super-Ink4/Arf mice do not develop glucose intolerance with agi…