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The influence of the major histocompatibility complex (H-2) on experimental diabetes in mice

Mice with different histocompatibility loci on an identical background genome (congenic resistant lines of mice) were used to study the possible influence of the histocompatibility complex on experimental diabetes. The major histocompatibility complex (H-2) was not found to influence the diabetogenic effect of encephalomyocarditis (EMC) virus. In contrast the glucose intolerance following heterolo

5′-AMP hydrolysis by suspensions and homogenates of pancreatic islet cells from normal and cortisone-treated rats

Suspensions of endocrine pancreas cells were prepared by shaking collagenase-isolated rat islets of Langerhans in calcium-free buffer. When incubated with 1.0 mM substrate at pH 7.4, the cells split, Pi from 5′-AMP at a rate of 87 nmol/h per μg DNA, and from β-glycerophosphate at a rate of 25 nmol/h per μg DNA Km for 5′ AMP was about 54 μM. Adenosine or theophylline inhibited the 5′-AMP hydrolysis

Detection and possible functional influence of antibodies directed againt the pancreatic islet cell surface.

Antibodies directed towards determinants on the surface of rat islet cells can be detected qualitatively by the indirect immunofluorescence or quantitatively by a specific radioassay for IgG. Antibodies are found in insulin-dependent diabetics or in rabbits immunized with islet cells. Such antibodies may affect the B-cell function as indicated by the inhibition of incorporation of radioactive leuc

Islet-Cell-Surface Antibodies in Juvenile Diabetes Mellitus

Using an indirect immunofluorescence test on suspensions of viable, insulin-producing islet cells from rats, we found that 32 per cent (28/88) of insulin-treated patients with juvenile diabetes have isletcell-surface antibodies in their circulation. These antibodies also occurred in four of nine children with glucose intolerance, in one of 24 healthy children and in nondiabetic children with thyro

Possible toxic effects of normal and diabetic patient serum on pancreatic B-cells

Serum from normal blood-donors and juvenile diabetic patients inhibited Rb+ accumulation and stimulated release of 51Cr and insulin in suspensions of dispersed pancreatic islet cells prepared from ob/ob mouse islets, which are rich in B-cells. The effects indicate the presence of a B-cytotoxic factor in human serum. Serum from mouse and fetal calf also inhibited the islet cell accumulation of Rb+.

Scanning electron microscopy of surface changes on dispersed pancreatic β-cells following stimulation of insulin release

The surface structure of isolated viable β-cells was studied by scanning electron microscopy. Suspensions of islet cells were prepared from the β-cell-rich islets of the ob/ob mouse. Cells incubated with and without D-glucose were fixed while in suspensions, filtered onto Nucleopore filters and prepared for scanning electron microscopy by the critical point drying procedure. After incubation in gl

Potassium ion-activated hydrolysis of p-nitrophenyl phosphate in pancreatic islet-cell membranes

Hydrolysis of p nitrophenyl phosphate was measured in a fraction enriched in plasma membranes from pancreatic islets of non inbred ob/ob mice. Hydrolysis was stimulated by K+ (10mM) in the pH range 5-10; a small peak of K+ induced activation was observed between pH 7.5 and 8. Both the K+ induced activation and the hydrolysis in the absence of K+ were Mg2+ dependent; maximum activation was obtained

Alloxan cytotoxicity in vitro : Inhibition of rubidium ion pumping in pancreatic β cells

Exposing micro-dissected pancreatic islets of non-inbred ob/ob mice to 2-5 mM-alloxan for 10 min decreased the ability of the islets to accumulate Rb+. Rb+ accumulation in pieces of exocrine pancreas was unaffected by alloxan. When islets were treated with alloxan in the presence of 2-20 mM-D-glucose, the Rb+-accumulating ability was protected in a dose-dependent manner. The protective action of D

Tracing charge transfer in argon dimers by XUV-pump IR-probe experiments at FLASH

Charge transfer (CT) at avoided crossings of excited ionized states of argon dimers is observed using a two-color pump-probe experiment at the free-electron laser in Hamburg (FLASH). The process is initiated by the absorption of three 27-eV-photons from the pump pulse, which leads to the population of Ar2+*-Ar states. Due to nonadiabatic coupling between these one-site doubly ionized states and tw

Alloxan cytotoxicity in vitro : Microscope photometric analyses of trypan blue uptake by pancreatic islet cells in suspension

Suspensions of islet cells were prepared by shaking pancreatic islets from non inbred ob/ob mice in a Ca 2+ free buffer. The cells were incubated with or without 20 mM alloxan, and subsequently with Trypan Blue. The uptake of Trypan Blue by cell nuclei was analysed by microscope photometry and by counting the frequency of cells appearing stained on visual inspection. Cells classified as stained o

The pancreatic β cell recognition of insulin secretagogues. XII. Insulin release in response to halogenated hexosamines

The effects of N iodoacetyl 2 amino 2 deoxy (D) glucose and various N bromoacetylglycosylamines on the release of insulin from microdissected pancreatic islets of non inbred ob/ob mice were studied. N Bromoacetyl β (D) glucosylamine (10 m(M)) initiated insulin release in the absence of (D) glucose and, at concentrations of 2.5-10 m(M), but not 20 m(M), potentiated insulin release in response to 10

Preparation and characterization of plasma membrane-enriched fractions from rat pancreatic islets

Methods have been developed for the isolation on a semi-micro scale of a plasma membrane-enriched fraction from rat islets of Langerhans. An important feature of these experiments is the use of 125I-labeled wheat germ agglutinin as a specific probe for plasma membrane-containing fractions. The partly purified plasma membrane fraction had a density in sucrose of about 1.10 and was enriched in the a