Autoantibodies against 21-hydroxylase (P450c21) are common in idiopathic autoimmune Addison’s disease. In the present work, we have developed a sensitive radiobinding assay using in vitro translated recombinant human 35S-P450c21. Levels of P450c21 antibodies (P450c21-Ab) were expressed as a relative index (P450c21 index) using a P450c21-Ab positive Addisonian serum and two antibody-negative health

The effects of plasmapheresis on islet autoantibody levels, C-peptide (β-cell function), and hemoglobin-A1c (HbA1c, metabolic control) were tested in a prospective blinded study of 18 newly diagnosed insulin-dependent diabetes mellitus (IDDM) patients randomly assigned to receive plasmapheresis (P), carried out as double filtration, or sham (S) treatment at diagnosis and 3 months thereafter. At di

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

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

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

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

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

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

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

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

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

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

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

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

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 (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.