Comparison of liquid phase radiobinding assay and solid phase ELISA for the measurement of insulin antibodies and insulin autoantibodies in serum

Sera containing insulin antibodies from 20 insulin-treated diabetic patients, sera containing insulin autoantibodies from 20 insulin-naive non-diabetic patients, and from 10 normal controls, were tested at 1:20 dilution in three different radioimmunoassays (RIA) and an enzyme linked immunosorbent assay (ELISA), using a highly purified human insulin ligand. The RIA using insulin radiolabelled at multiple sites detected insulin antibodies in 17/20 and insulin autoantibodies in 13/20 sera. The same RIA using A-14-monoiodinated insulin was sensitive to antibodies and autoantibodies in all the sera. The same RIA using sera after insulin extraction detected only 13/20 diabetic sera and 9/20 autoimmune sera as positive, owing to a substantial rise in non-specific binding of the control sera. ELISA was sensitive to insulin antibodies and autoantibodies in every case. When binding curves for ELISA and the most sensitive RIA were compared using serial dilutions of four insulin antibody containing sera and four insulin autoantibody containing sera, antibody titres varied from 1.1 to 3.8 times higher in ELISA, and autoantibody titres from 10.6 to 28.6 times higher in ELISA. These studies indicate that ELISA is more sensitive than RIA to insulin antibodies, and in particular to insulin autoantibodies.     

Autoradiographic localization of peripheral benzodiazepine, dihydroalprenolol and arginine vasopressin binding sites in the pituitaries of control, stalk transected and Brattleboro rats

The autoradiographic distribution of [3H]arginine vasopressin, [3H]spiperone, [3H]GABA, [3H]dihydroalprenolol and the peripheral-type benzodiazepine ligand [3H]Ro5-4864 were examined in the rat pituitary before and after pituitary stalk transection. Stalk transection produced dramatic changes in the cellular architecture of the pars nervosa. Glial fibrillary acidic protein, an astrocyte marker reported in pituicytes, increased after stalk transection, whereas neurofilament, a marker for neuronal innervation, was lost. These structural changes demonstrated a successful stalk transection, permitting interpretation of changes in the densities of several [3H]-ligands over the three lobes. [3H]Ro5-4864 binding was markedly increased, suggesting that this site was located on the pituicytes. Conversely [3H]spiperone and [3H]arginine vasopressin binding density over the pars nervosa decreased. In the mutant diabetes insipidus rat (Brattleboro), which lacks pituitary vasopressin, [3H]arginine vasopressin binding was undetectable in the pars nervosa. [3H]dihydroalprenolol and [3H]GABA binding sites were unchanged by the lesion. These results are discussed in terms of the occurrence of functional acceptors on pituicytes and their possible role in neurohydrophyseal secretions.     

A study of adaptive responses in cell signaling in migraine and cluster headache: correlations between headache type and changes in gene expression

The project was an investigation into whether changes in the expression of G-proteins underlie altered cell signaling in migraine and cluster headache. The basis for this assumption is that altered physiological responses are seen in migraineurs and that differences in cell signaling are detected biochemically in various cell types isolated from peripheral blood. Levels of three G-protein mRNAs—Gsα, Giα, and Gqα were quantified in lymphocytes from clinically well-defined migraine and cluster headache patients and correlated with headache type and influence of drug treatment. Giα mRNA was reduced by 50% in all migraine patients compared with control subjects; similarly in patients with or without aura, in patients with a migraine headache at the time of sampling, and patients in a quiescent state. No reduction in the levels of Gsα or Gqα mRNA were seen in migraine patients. A smaller reduction was seen in cluster headache patients, most marked in those without medication. Levels of Gsα. mRNA were significantly reduced in cluster headache patients compared with migraine patients. The marked down-regulation of Giα mRNA in migraine, whether quiescent or acute, indicates either an adaptive response to headache in this group of patients or that low levels of Giα mRNA make individuals more susceptible to migraine.     

The effect of hypotonicity, glutamine, and glycine on red cell preservation

BACKGROUND : Red cells (RBCs) stored in hypo-os-molar additive solutions with the same concentrations of adenine, dextrose, mannitol, and sodium chloride and varied amounts of ammonium, phosphate, glycerol, and glutamine were better preserved than RBCs in the standard additive solution (Adsol). Cell swelling occurred in all the experimental additives. This observation prompted the evaluation of glutamine and glycine alone, as well as a combination of glutamine and glycine, all of which have been described as producing swelling of rat liver cells. STUDY DESIGN AND METHODS : Aliquots of RBCs were stored at 4°C in Adsol or experimental additive solutions (EASs) all containing adenine, 2 mM; dextrose, 110 mM; mannitol, 55 mM; and sodium chloride, 50 mM. EAS 42 had, in addition, glutamine, 10 mM; glycine 5 mM; and phosphate, 20 mM. EAS 43 had glutamine, 10 mM; glycine, 10 mM; and phosphate 20 mM. EAS 44 had glutamine, 10 mM; EAS 45 had glutamine, 10 mM, and phosphate, 20 mM; and EAS 46 had only glycine, 10 mM. At intervals, measurements were made of mean corpuscular volume, mean corpuscular hemoglobin concentration, morphology, ATP, hemolysis, supernatant potassium, ammonia, pH, and microvesicles shed. RESULTS : The initial mean corpuscular volumes were larger in all EASs than in Adsol, but the greatest difference was between EASs 44 and 46 (108 fL) and Adsol (86 fL) (p<0.001). The morphology scores were significantly better in all the EASs (p<0.04). The ATPs were significantly greater in all the EASs (p<0.001), and highest in those with phosphate. Potassium leakage and hemolysis were less in the EASs (p<0.001). The ammonia levels were higher in all the EASs than in Adsol, with the exception of EAS 46. During storage, the extracorpuscular and intracorpuscular pH levels were essentially identical. The shedding of microvesicles was greatly reduced in all the EASs. CONCLUSION : Cell swelling induced in RBCs after collection appears to improve preservation. Ammonia and phosphate enhance RBC ATP maintenance. Glycine decreases the formation of ammonia by RBCs stored in a hypotonic medium.     

Potential risks and benefits of HIV treatment simplification: a simulation model of a proposed clinical trial.

BACKGROUND: In recent studies, subjects who had achieved suppression of the human immunodeficiency virus (HIV) RNA level while receiving an initial 3-drug antiretroviral regimen successfully maintained suppression while receiving treatment with a "boosted" protease inhibitor (PI) alone. We projected the long-term outcomes of this treatment simplification strategy to inform the design of a proposed multicenter, randomized clinical trial. METHODS: We used published studies to estimate the efficacy, adverse effects, and cost of a sequence of HIV drug regimens for the simplification strategy, compared with those outcomes for the current standard-of-care (SOC) strategy. Using a published simulation model of HIV disease, we projected life expectancy, discounted quality-adjusted life expectancy (QALE), and discounted lifetime medical costs for each strategy. RESULTS: Subjects who have not developed PI-resistant HIV infection at the time of failure of the simplification regimen have a greater life expectancy (27.9 vs. 27.1 years) and QALE (14.9 vs. 14.7 years), compared with SOC subjects, because they receive an additional line of therapy without negative consequences for future treatment options. The QALE for the simplification strategy remains higher than that for the SOC, unless a large proportion of patients experiencing virologic failure while receiving the simplification regimen develop PI resistance. Depending on the probability of simplification regimen failure, the advantage is maintained even if HIV develops PI resistance in 42%-70% of subjects. Projected lifetime costs are $26,500-$72,400 per person lower for the simplification strategy than for the SOC strategy. CONCLUSIONS: An HIV treatment simplification strategy involving use of a boosted PI alone may lead to longer survival overall at lower cost, compared with the SOC combination therapy, because the simplification strategy potentially adds an additional line of therapy. The risk of emergence of PI resistance during treatment with a simplified regimen is a critical determinant of the viability of this strategy.