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Biomedical subjects

C Ricordi

Publications and source records attributed to C Ricordi.

At least 307 records · Page 17Linked to original sources
PubMed1986

A method for the mass isolation of islets from the adult pig pancreas.

A method for mass isolation of islets from the pig pancreas is described. The procedure involves the use of an enzymatic and mechanical pancreatic digestion procedure followed by filtration and separation of the islets on Ficoll gradients. A remarkably high yield of purified islets has been obtained from the pig pancreas with this procedure. The islets are morphologically intact and respond to acute stimulation with glucose in vitro.

Animals↗
PubMedDate not supplied

Islet isolation assessment in man and large animals.

Recent progress in islet isolation from the pancreas of large mammals including man, accentuated the need for the development of precise and reproducible techniques to assess islet yield. In this report both quantitative and qualitative criteria for islet isolation assessment were discussed, the main topics being the determination of number, volume, purity, morphologic integrity and in vitro and in vivo function tests of the final islet preparations. It has been recommended that dithizone should be used as a specific stain for immediate detection of islet tissue making it possible to estimate both the total number of islets (dividing them into classes of 50 mu diameter range increments) and the purity of the final preparation. Appropriate morphological assessment should include confirmation of islet identification, assessment of the morphological integrity and of the purity of the islet preparation. The use of fluorometric inclusion and exclusion dyes together have been suggested as a viability assay to simultaneously quantitate the proportion of cells that are intact or damaged. Perifusion of islets with glucose provides a dynamic profile of glucose-mediated insulin release and of the ability of the cells to down regulate insulin secretion after the glycemic challenge is interrupted. Although perifusion data provides a useful guide to islet viability the quantity and kinetics of insulin release do not necessarily predict islet performance after implantation. Therefore, the ultimate test of islet viability is their function after transplantation into a diabetic recipient. For this reason, in vivo models of transplantation of an aliquot of the final islet preparation into diabetic nude (athymic) rodents have been suggested. We hope that these general guidelines will be of assistance to standardize the assessment of islet isolations, making it possible to better interpret and compare procedures from different centers.

Animals↗
PubMedDate not supplied

Characterization of the chlorpropamide-alcohol-flush in patients with type 1 and type 2 diabetes.

The aim of the present paper was to evaluate the prevalence of the chlorpropamide-alcohol-flush (CPAF) in patients with type 2 and with type 1 diabetes. Ninety-seven patients with type 2 diabetes and 33 with type 1 diabetes drank 40 ml vermouth 12 h after placebo and again 12 h after 1 tablet of chlorpropamide (250 mg) or 12 h after the last of repeated administrations of chlorpropamide (250 mg b.i.d. for 2 days). Skin temperature was recorded in all patients by a thermocouple probe connected to the left cheek. In 47 patients serum concentrations of chlorpropamide and of its metabolite CBSU were also determined. The prevalence of CPAF was similar in type 1 and type 2 diabetes, was greater in women than in men, and was significantly greater after repeated administrations than after one single administration of chlorpropamide. The increase of skin temperature during a 30-min period was significantly higher in patients with CPAF than in patients without CPAF. Serum concentrations of chlorpropamide and of its metabolite CBSU were more elevated after 4 than after 1 tablet of chlorpropamide, but were not significantly different in patients with and without CPAF. These data indicate that both genetic factors and the amount of chlorpropamide used affect the appearance of CPAF. To assess the possible role of serotonin and of dopamine in the CPAF, some patients with CPAF were tested again after treatment with metergoline, an antiserotonin agent, or with bromocriptine, a dopamine-agonist. Neither drug influenced the CPAF, indicating that the two neurotransmitters are not involved in the CPAF.

Bromocriptine↗
PubMedDate not supplied

Rapid development of extensive macrovascular calcifications in a type I diabetic patient.

This is a case report of a 35-year-old woman with a 15-year history of type I diabetes mellitus, who developed extensive macrovascular calcifications of the abdominal aorta and all its tributaries within 7 months of developing renal insufficiency. The patient was maintained on hemodialysis and peritoneal dialysis for a total of 3 months, then underwent combined cadaveric renal and pancreatic islet transplantation. Although some vascular calcifications are known to occur in elderly patients and in patients with long-standing uremia, it was the rapidity and extent of development of these lesions in this young woman that is astonishing.

Adult↗
PubMedDate not supplied

Protection of islets in culture by delivery of oxygen binding neuroglobin via protein transduction.

Islet transplantation has become an accepted method to treat type 1 diabetes. To succeed and achieve normal levels of glucose in transplant recipients, the quality of the transplanted islets is of the utmost importance. Lack of oxygen during organ procurement, islet isolation, and subsequent culture triggers apoptosis or necrosis and loss of islet function, causing the yield and quality to diminish. A promising candidate for cytoprotection against oxygen deprivation is neuroglobin (Ngb). Ngb is a recently described member of globin family and is expressed in neurons, retina, and pancreatic islets. To overexpress this protein in the islets and study its ability to protect them, we utilized protein transduction. Protein transduction is achieved by fusing Ngb to the TAT/PTD transduction domain, a peptide originated from the HIV transcriptional transactivator protein. Our study proved that TAT-Ngb is an efficient fusion protein capable of protecting the human islets in culture from loss of cell mass and function, thus increasing the quality of transplantable islets. If the islets could be cultured for a longer period of time without suffering harmful effects, it would be possible to precondition the recipient and there would be more time to assess their quality and function before transplantation.

Automation↗