Search results for "Islet"
showing 10 items of 98 documents
Recovery of endogenous beta cell function in non-human primates following chemical diabetes induction and islet transplantation
2009
Objectives: To describe the ability of non-human primate endocrine pancreata to re-establish endogenous insulin production after chemical beta cell destruction. Research Design and Methods: Eleven monkeys (macaca fascicularis) were rendered diabetic with streptozotocin. Eight diabetic monkeys received intraportal porcine islet transplantation. Results: Two monkeys transplanted after 75 days of insulin dependent diabetes, showed recovery of endogenous C-peptide production a few weeks after transplantation, concomitant with graft failure. Histological analysis of the pancreas of these monkeys showed insulin-positive cells, single or in small aggregates scattered in the pancreas and adjacent t…
Gene therapy for type 1 diabetes: is it ready for the clinic?
1999
This review, in addition to updating the growing list of type 1 diabetes- relevant gene therapies, offers an outline of short-term objectives that can readily be met to move, at least, adenoviral and adeno-associated viral-based protocols into the clinic, first as a means of facilitating islet allografts as well as platforms with which to introduce immunoregulatory transgenes. A wide array of genes have been tested to restore insulin production, to drive the differentiation of insulin-producing progenitors, and to confer immunosuppression in an antigen- and tissue-restricted manner.
Synthesis and evaluation of (S)-2-(2-[18F]fluoroethoxy)-4-([3-methyl-1-(2-piperidin-1-yl-phenyl)-butyl-carbamoyl]-methyl)-benzoic acid ([18F]repaglin…
2004
18F-labeled non-sulfonylurea hypoglycemic agent (S)-2-(2-[(18)F]fluoroethoxy)-4-((3-methyl-1-(2-piperidin-1-yl-phenyl)-butylcarbamoyl)-methyl)-benzoic acid ([(18)F]repaglinide), a derivative of the sulfonylurea-receptor (SUR) ligand repaglinide, was synthesized as a potential tracer for the non-invasive investigation of the sulfonylurea 1 receptor status of pancreatic beta-cells by positron emission tomography (PET) in the context of type 1 and type 2 diabetes. [(18)F]Repaglinide could be obtained in an overall radiochemical yield (RCY) of 20% after 135 min with a radiochemical purity higher than 98% applying the secondary labeling precursor 2-[(18)F]fluoroethyltosylate. Specific activity w…
SNAP-25a and -25b isoforms are both expressed in insulin-secreting cells and can function in insulin secretion
1999
The tSNARE (the target-membrane soluble NSF-attachment protein receptor, where NSF is N-ethylmaleimide-sensitive fusion protein) synaptosomal-associated protein of 25 kDa (SNAP-25) is expressed in pancreatic B-cells and its cleavage by botulinum neurotoxin E (BoNT/E) abolishes stimulated secretion of insulin. In the nervous system, two SNAP-25 isoforms (a and b) have been described that are produced by alternative splicing. Here it is shown, using reverse transcriptase PCR, that messages for both SNAP-25 isoforms are expressed in primary pancreatic B and non-B cells as well as in insulin-secreting cell lines. After transfection, both isoforms can be detected at the plasma membrane as well a…
Nitric oxide synthase isozymes antibodies
1995
Three isozymes of nitric oxide synthase (NOS) have been identified, cDNAs isolated and sequenced, and antibodies produced against each isozyme. Isozyme I (found primarily in central and peripheral neuronal cells), II (in cytokine-induced cells), and III (in endothelial cells) show less than 58% identity in the deduced amino acid sequences from humans. Many investigators have produced isozyme-specific antibodies and used these antibodies to locate these proteins in various cells and tissues. NOS-I is constitutively expressed, and the enzymatic activity is regulated by Ca2+ and calmodulin. The anti-NOS-I antibodies have allowed investigators to characterize non-adrenergic non-cholinergic neur…
Exenatide prevents statin-related LDL receptor increase and improves insulin secretion in pancreatic beta cells (1.1E7) in a protein kinase A-depende…
2022
Statins are primary drugs in the treatment of hyperlipidemias. This group of drugs is known for its beneficial pleiotropic effects (e.g., reduction of inflammatory state). However, a growing body of evidence suggests its diabetogenic properties. The culpable mechanism is not completely understood and might be related to the damage to pancreatic beta cells. Therefore, we conceived an in vitro study to explore the impact of atorvastatin on pancreatic islet beta cells line (1.1.E7). We evaluated the influence on viability, insulin, lowdensity lipoprotein (LDL) receptor, and proprotein convertase subtilisin/kexin type 9 (PCSK9) expression. A significant drop in mRNA for proinsulin and insulin e…
Cytokine regulatory effects on α-1 proteinase inhibitor expression in NOD mouse islet endothelial cells
2002
Human microvascular islet endothelial cells (IEC) exhibit specific morphological and functional characteristics that differ from endothelia derived from other organs. One of these characteristics is the expression of alpha-1 proteinase inhibitor (Api). In this study, we observed its expression in nonobese diabetic (NOD) mouse IEC, in relation to the occurrence of type 1 diabetes and in response to cytokines, namely IL-1 beta and IL-10. In addition, IL-10-deficient NOD mice as well as IL-10 transgenic NODs were studied. Results have demonstrated that Api expression is: (i) highly specific for IEC in NOD mouse islets, as for humans; (ii) linked to the occurrence of early type 1 diabetes, and …
Synthesis and evaluation of a glibenclamide glucose-conjugate: a potential new lead compound for substituted glibenclamide derivatives as islet imagi…
2007
The search for novel SUR1-ligands originates from the idea to influence the in vivo behaviour by adding new structural moieties to the glibenclamide structure while preserving its binding affinity. Important application of novel conjugates might be their use as radioactively labelled tracer probes in the non-invasive investigation of the islet mass. It is known that the imaging quality of a tracer could be improved by increasing its hydrophilicity, which leads to a reduced plasma protein binding and diminished the unspecific uptake by various organs. In this study the glucose molecule was chosen as a substitute of glibenclamide to enhance hydrophilicity. As expected glucose conjugation lead…
Studies of malformation syndromes of man XIB: the cerebro-hepato-renal syndrome of zellweger: Comparative pathology
1976
A study of 11 autopsied cases of the cerebro-hepato-renal syndrome of Zellweger (ZS) is reported. All cases had severe, persistent congenital hypotonia, hepatic lobular disarray, renal cortical cysts and pulmonary hypoplasia. Many had cardiovascular malformations, hepatomegaly, cerebral cortical gyral maldevelopment and pancreatic islet hyperplasia. Additional, less frequent findings are delineated. Results of iron content studies of hepatic and renal tissues are related to age of survival and possible development of fibrosis.
Image segmentation to evaluate islets of langherans
2008
This contribution deals with an unsupervised system to process digital photomicrographs in order to locate and analyze islets of Langherans in human pancreases. The experiment has been conducted on real data and, though we are still going to complete the evaluation of the whole method, we expect to define a set of proper features (e.g. area, perimeter, fractal dimension, shape complexity, texture and entropy) useful for a fast and reliable counting of healthy cells. In particular, this research aims to measure the advisability of a possible implantation in patients affected by type I diabetes mellitus