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Pancreatic beta-cell function evaluated by intravenous glucose and glucagon stimulation. A comparison between insulin and c-peptide to measure insulin secretion

Insulin and C-peptide responses to 0.5 g kg-1 intravenous glucose and 1.0 mg glucagon were studied in 34 healthy subjects (age 19-78 years, mean 45). Fasting blood glucose (r=0.59; p<0.001) and glycosylated haemoglobin (r=0.61; p<0.001) increased with age, but not the initial C-peptide and insulin responses to the glucose infusion. However, the C-peptide response at 70 min (r=0.36; p<0.05), 80 min

Serum exchange and use of dilutions have improved precision of measurement of islet cell antibodies

In an attempt to improve the diagnostic value of measuring antibodies to islet cell cytoplasmic antigen, coded sera were distributed to 38 laboratories and results were returned for analysis. Comparison between laboratories revealed that results for some individual sera differed by up nine doubling dilutions and even within laboratories duplicate samples could differ by six doubling dilutions. By

[24] Preparation of Stable Radioiodinated Polypeptide Hormones and Proteins Using Polyacrylamide Gel Electrophoresis

This chapter discusses the preparation of stable radioiodinated polypeptide hormones and proteins using polyacrylamide gel electrophoresis. Radioactively labeled polypeptide hormones and proteins are widely used as tracers in radioimmunoassays and receptor studies. The peptide or protein is most easily labeled using iodination with 125I or 131I. The radioactive iodine is substituted in the tyrosin

Plasmapheresis in the initial treatment of insulin-dependent diabetes mellitus in children

Several factors indicate that autoimmune mechanisms may play a part in the aetiology of insulin-dependent diabetes mellitus. At the onset of the disease in 10 children (aged 11-16 years) plasmapheresis was performed four times over one to two weeks. Seventeen age-matched children with the same clinical features served as controls. The C-peptide concentrations at onset were the same in the two grou

Expression of major histocompatibility antigens on pancreatic islet cells

Insulin-independent diabetes mellitus is often accompanied by manifestations of autoimmunity and is frequently associated with certain HLA haplotypes, predominantly DR3 and DR4. Because the major histocompatibility antigens are important determinants of the immune response in various tissues, we have investigated their expression on the pancreatic islet cells. Human, mouse, or rat islets of Langer

Stable lodinated polypeptide hormones prepared by polyacrylamide gel electrophoresis

Iodination of several insulin and proinsulin preparations, human growth hormone and bovine pancreatic polypeptide was performed using H2O2 and lactoperoxidase or chloramine T. The iodination mixtures were fractionated by polyacrylamide gel electrophoresis at pH 9.15 in long gel rods followed by simple elution of the iodinated products from thin gel slices. With this method 125I tracers with long s

Trypan Blue as a marker of plasma membrane permeability in alloxan-treated mouse islet cells

Suspensions of pancreatic islet cells from noninbred ob/ob-mice were incubated with Trypan Blue. Microscope photometry showed that apparently viable cells excluded the dye completely, whereas the nuclei of nonviable cells accumulated Trypan Blue by a saturable process. The nucleus-to-medium dye gradient was more then 30∶1 in media containing 0.1% or less Trypan Blue. The apparent affinity constant

Effects of dextran-linked chloromercuribenzoic acid on insulin release from microdissected pancreatic islets

Insulin release in response to dextran-linked p-chloromercuribenzoic acid was studied in microdissected pancreatic islets of non-inbred ob/ob-mice. No contamination of the dextran-linked mercurial with free chloromercuribenzoic acid was detected before or after the incubation with islets. In comparison with free mercurial, of the same thiol-blocking activity, the dextran-linked compound had a weak

On the possible role of thiol groups in the insulin-releasing action of mercurials, organic disulfides, alkylating agents, and sulfonylureas

The thiol activity of pancreatic islets was spectrophotometrically assayed as the formation of 6-mercaptonicotinic acid from the organic disulfide, 6, 6’-dithiodinicotinic acid. Islets containing more than 90% β-cells were microdissected from non-inbred oblob-mice. Comparisons of intact with homogenized islets indicated that the organic disulfide penetrates relatively slowly into the β-cells. When

Effects of insulin secretagogues on phospholipid metabolism in pancreatic β-cells

The effect of insulin secretagogues on the incorporation of [32P]ortho-phosphate into phospholipids was studied in microdissected islets from obese-hyperglycemic mice. Increased 32P-labelling was observed after incubation for 60 min with 10 mM l-leucine, 10 mM l-arginine or 20 mM d-glucose. Most of the label occurred in the phosphatidyl inositol fraction. The effect of l-leucine was additive to th

Specificity of cyclic AMP potentiation of glucose-stimulated insulin release

The insulin-releasing activities of cyclic and non-cyclic nucleotides were studied with isolated pancreatic islets from obese-hyperglycemic mice. Substitution of cylidine, inosine, guanosine, or uridine for the adenosine moeity of cyclic 3ʹ,5ʹ-adenosine monophosphate was associated with a total loss of insulin-releasing ability. The 5ʹ-nucleotide triphosphate derivatives of these nucleotides were

Effects of neutral and dibasic amino acids on the in vitro release of insulin

The insulin-releasing ability of some neutral and di-basic amino acids was studied in an in vitro system using micro-dissected pancreatic islets with a high proportion of insulin-producing β-cells. The neutral amino acids l-alanine and α-aminoisobutyric acid had no substantial effects on basal and glucose-stimulated insulin release. In contrast, 5–20 mm of the dibasic amino acid l-arginine gradual

Specificity of leucine stimulation of insulin release

The ability of leucine to stimulate insulin release was studied in an in vitro system, using microdissected pancreatic islets with a high proportion of the insulin-producing β-cells. When tested in a glucose-free medium, l-leucine stimulated insulin release over a wide concentration range with maximum effect at about 20 mm. The stimulation of insulin release was additive to that elicited by 10 mm

Orthostatic hypotension and cardiovascular risk

Orthostatic hypotension (OH) is a cardinal sign of cardiovascular (CV) autonomic dysfunction as a result of autonomic nervous system failure to control the postural hemodynamic homeostasis. The proportion of individuals with OH increases with aging and chronic conditions, such as neurodegenerative diseases, hypertension, heart failure, diabetes, renal dysfunction, autoimmune diseases, and cancer.

Third-trimester prediction of successful vaginal birth after one cesarean delivery—A Swedish model

Introduction: The objective was to create a clinically useful prediction model for vaginal birth in trial of labor after one cesarean section, appropriate for a third trimester consultation. Material and methods: Women with one cesarean section and at least one following delivery (N = 38 686) in the Swedish Medical Birth Register, 1998-2013, were studied. The women were randomly divided into one d

Geosmin Attracts Aedes aegypti Mosquitoes to Oviposition Sites

Geosmin is one of the most recognizable and common microbial smells on the planet. Some insects, like mosquitoes, require microbial-rich environments for their progeny, whereas for other insects such microbes may prove dangerous. In the vinegar fly Drosophila melanogaster, geosmin is decoded in a remarkably precise fashion and induces aversion, presumably signaling the presence of harmful microbes

Inguinal Vascular Surgical Wound Protection by Incisional Negative Pressure Wound Therapy : A Randomized Controlled Trial-INVIPS Trial

OBJECTIVE: A randomized controlled trial (RCT) was undertaken to determine the effect of negative pressure wound therapy (NPWT) on closed incisions after inguinal vascular surgery regarding surgical site infections (SSIs) and other wound complications. BACKGROUND: SSIs are a major concern in open vascular procedures involving the inguinal region. Prophylactic NPWT on closed incisions has shown pro