Search results for "Islet"

Little Egret Egretta garzetta (Linnaeus, 1766) ( Pelecaniformes Ardeidae) and Eurasian crag martin Ptyonoprogne rupestris (Scopoli, 1769) (Passerifor…

2021

For the first time, the nesting of Eurasian crag martin Ptyonoprogne rupestris (Scopoli, 1769) (Passeriformes Hirundinidae) and Little egret Egretta garzetta (Linnaeus, 1766) (Pelecaniformes Ardeidae) in the Aegadian Islands (W-Sicily, Italy) is reported. Of particular interest is the nesting of the Little egret on the island of Maraone resulting in the first report for Sicily of a heronry on a marine island. Although this nesting environment has already been established in Sardinia, it should be emphasized that until now the establishment of a heronry has never been detected on an islet so far from the mainland.

Effect of tormentic acid on insulin secretion in isolated rat islets of langerhans

1989

Tonnentic acid was isolated as the hypoglycemic agent of Poterium ancistroides Desf. The present study reports effects of this compound on isolated islets of Langerhans. We demonstrate that tormentic acid in the presence of 1.66 mM glucose initiates insulin secretion by isolated rat islets of Langerhans in a dose-dependent fashion at concentrations ranging from 0.05 to 0.5 mM. However, the compound has no effect on the insulin-releasing capacity of 16.6 mM glucose. Similar results were obtained with the sulfonylurea glibenclamide (0.01 mM) used as a reference. These results suggest that the hypoglycemic effect of tormentic acid is due to a diect effect of the compound in vitro.

Compromised central tolerance of ICA69 induces multiple organ autoimmunity

2014

For reasons not fully understood, patients with an organ-specific autoimmune disease have increased risks of developing autoimmune responses against other organs/tissues. We identified ICA69, a known β-cell autoantigen in Type 1 diabetes, as a potential common target in multi-organ autoimmunity. NOD mice immunized with ICA69 polypeptides exhibited exacerbated inflammation not only in the islets, but also in the salivary glands. To further investigate ICA69 autoimmunity, two genetically modified mouse lines were generated to modulate thymic ICA69 expression: the heterozygous ICA69(del/wt) line and the thymic medullary epithelial cell-specific deletion Aire-ΔICA69 line. Suboptimal central neg…

In Vitro Cultured Islet‐Derived Progenitor Cells of Human Origin Express Human Albumin in Severe Combined Immunodeficiency Mouse Liver In Vivo

2004

Studies in rodents suggest the presence of a hepatopancreatic stem cell in adult pancreas that may give rise to liver cells in vivo. The aim of the present study was to determine the ability of human islet-derived cells to adopt a hepatic phenotype in vivo. Cultured human islet-derived progenitor cells that did not express albumin in vitro were stained with the red fluorescent dye PKH26 and injected into the liver of severe combined immunodeficiency mice. After 3 or 12 weeks, red fluorescent cells were detected in 11 of 15 livers and were mostly single cells that were well integrated into the liver tissue. Human albumin was found in 8 of 11 animals by immunohistochemistry, and human albumin…

Multilayer capsules: a promising microencapsulation system for transplantation of pancreatic islets

2001

In 1980, Lim and Sun introduced a microcapsule coated with an alginate/polylysine complex for encapsulation of pancreatic islets. Characteristic to this type of capsule is, that it consists of a plain membrane which is formed during a single procedural step. With such a simple process it is difficult to obtain instantly a membrane optimized with respect to all the properties requested for islet transplantation. To overcome these difficulties, it is recommended to build up the membrane in several consecutive steps, each optimized for a certain property. In this study, we have analysed such a multilayer microcapsule for the encapsulation of pancreatic islets. Therefore, empty and islet contai…

Vascular Endothelial Growth Factor-Releasing Microspheres Based on Poly(ε-Caprolactone-PEG-ε-Caprolactone)-b-Poly(L-Lactide) Multiblock Copolymers In…

2020

Pancreatic islet transplantation is a promising advanced therapy that has been used to treat patients suffering from diabetes type 1. Traditionally, pancreatic islets are infused via the portal vein, which is subsequently intended to engraft in the liver. Severe immunosuppressive treatments are necessary, however, to prevent rejection of the transplanted islets. Novel approaches therefore have focused on encapsulation of the islets in biomaterial implants which can protect the islets and offer an organ-like environment. Vascularization of the device’s surface is a prerequisite for the survival and proper func- tioning of transplanted pancreatic islets. We are pursuing a prevascularization s…

Dietary polyphenols as antidiabetic agents: Advances and opportunities

2020

Abstract Dietary polyphenols have been widely investigated as antidiabetic agents in cell, animals, human study, and clinical trial. The number of publication (Indexed by Web of Science) on “polyphenols and diabetes” significantly increased since 2010. This review highlights the advances and opportunities of dietary polyphenols as antidiabetic agents. Dietary polyphenols prevent and manage Type 2 diabetes mellitus via the insulin‐dependent approaches, for instance, protection of pancreatic islet β‐cell, reduction of β‐cell apoptosis, promotion of β‐cell proliferation, attenuation of oxidative stress, activation of insulin signaling, and stimulation of pancreas to secrete insulin, as well as…

Standardization of islet isolation outcome: a new automatic system to determine pancreatic islet viability

2009

The Role of the α Cell in the Pathogenesis of Diabetes: A World beyond the Mirror

2021

Type 2 Diabetes Mellitus (T2DM) is one of the most prevalent chronic metabolic disorders, and insulin has been placed at the epicentre of its pathophysiological basis. However, the involvement of impaired alpha (α) cell function has been recognized as playing an essential role in several diseases, since hyperglucagonemia has been evidenced in both Type 1 and T2DM. This phenomenon has been attributed to intra-islet defects, like modifications in pancreatic α cell mass or dysfunction in glucagon’s secretion. Emerging evidence has shown that chronic hyperglycaemia provokes changes in the Langerhans’ islets cytoarchitecture, including α cell hyperplasia, pancreatic beta (β) cell dedifferentiati…

Fibril formation and toxicity of the non-amyloidogenic rat amylin peptide.

2012

Full-length native rat amylin 1-37 has previously been widely shown to be unable to form fibrils and to lack the toxicity of the human amylin form leading to its use as a non-amyloidogenic control peptide. A recent study has suggested that rat amylin 1-37 forms amyloidogenic β-sheet structures in the presence of the human amylin form and suggested that this property could promote toxicity. Using TEM analysis we show here fibril formation by synthetic rat amylin 1-37 and 8-37 peptides when the lyophilized HPLC purified peptides are initially dissolved in 20 mM Tris-HCl. Dissolution of synthetic rat amylin 1-37 and 8-37 peptides in H(2)O or phosphate buffered saline failed to produce fibrils.…