No abstract

We have tested for antibodies against human and pig eye muscle membrane antigens in the serum of patients with Graves' ophthalmopathy using an enzyme-linked immunosorbent assay (ELISA). Several different membrane preparations were used as source of putative antigen including a 100 000 \m=x\g pellet, a pellet depleted of the 100 000 \ m=x\g (microsome) fraction, and solubilized membranes. With eye muscle membrane pellets there were no significant differences for either serum or immunoglobulins between patients with ophthalmopathy, those with autoimmune thyroid disorders without eye disease, and normal subjects for either human or pig membranes, although tests were positive determined from the upper limit of normal in a few patients with or without eye disease. This was the case regardless of the enzyme-antibody conjugate used, the membrane protein concentration or serum or immunoglobulin dilution. Pre-absorption of tissue fractions, serum, or immunoglobulins, with red blood cells or liver powder, eye muscle membranes or skeletal muscle membranes did not significantly reduce background binding which was often very high, or enhance the difference between patients with ophthalmopathy and normal subjects. It was found that non-specific binding to the plastic surface of the microplates and/or tissue proteins, the presence, in human tissues, of blood-derived immunoglobulins which gave strong reactions in the ELISA, and variable fixation of membrane pellets to the plates were factors which made ELISA unsatisfactory when crude membrane pellets were used as antigen. When eye muscle membranes solubilized with standard agents including SDS, Triton X-100 and deoxycholine were tested, again no differences were demonstrated between patients with Graves' ophthalmopathy and normal subjects. However, when membranes were solubilized with the zwitterionic agent 'CHAPSO' approximately 20% of patients with Graves'

Chronic kidney disease is frequently associated with protein-energy wasting related to chronic inflammation and a resistance to anabolic hormones such as insulin and growth hormone (GH). In this study, we determined whether a new GH-releasing hormone super-agonist (AKL-0707) improved the anabolism and nutritional status of nondialyzed patients with stage 4-5 chronic kidney disease randomized to twice daily injections of the super-agonist or placebo. After 28 days, this treatment significantly increased 24-h GH secretion by almost 400%, without altering the frequency or rhythmicity of secretory bursts or fractional pulsatile GH release, and doubled the serum insulin-like growth factor-1 level. There was a significant change in the Subjective Global Assessment from 'mildly to moderately malnourished' to 'well-nourished' in 6 of 9 patients receiving AKL-0707 but in none of 10 placebo-treated patients. By dual-energy X-ray absorptiometry, both the mean fat-free mass and the body mineral content increased, but fat mass decreased, all significantly. In the AKL-0707-treated group, both serum urea and normalized protein equivalent of nitrogen appearance significantly decreased with no change in dietary protein intake, indicating a protein anabolic effect of treatment. Thus, our study shows that stimulation of endogenous GH secretion by AKL-0707 overcomes uremic catabolism of patients with advanced chronic kidney disease.

No abstract

One possible mechanism for Graves' ophthalmopathy is that the progressive orbital inflammation is initiated by formation of thyroglobulin (Tg)-anti-Tg immune complexes at sites of Tg binding to extraocular muscle membranes. In this study monoclonal antibodies (MCAB) against human Tg were used as probes (1) to identify Tg in eye muscle membranes prepared from normal subjects and (2) to measure binding of human Tg and Tg-anti-Tg immune complexes to eye muscle membranes. Reactivity of anti-Tg MCAB with Tg, thyroid, and eye muscle membranes was determined by binding of [125I]anti-Tg monoclonal antibody, an enzyme-linked immunosorbent assay (ELISA), and the indirect immunofluorescence technique. Seven membrane fractions, prepared by differential sucrose gradient centrifugation, were used. Whereas [125I]anti-Tg MCAB bound to all thyroid membrane fractions tested, no [125I]anti-Tg bound to eye muscle membranes. Similarly, reactivity of anti-Tg MCAB with eye muscle membranes was not demonstrated in ELISA or immunofluorescence tests. Although Tg-anti-Tg immune complexes bound to thyroid membranes, such complexes did not bind to eye muscle membranes. Significant binding of [125I]human Tg to eye muscle or thyroid membranes was not demonstrated for any membrane preparation. On the other hand moderate, but significant, binding to skeletal muscle was shown. Similar results were found using an ELISA. Binding of [125I]anti-Tg-Tg complexes of [125I]Tg to thyroid and eye muscle membranes was not affected by the presence of normal human serum, phosphate ions, pH, or incubation temperature, conditions claimed by others to be critical for Tg and Tg-anti-Tg immune complex binding. Since Tg is not present in normal human eye muscle a major role of Tg, or Tg-anti-Tg immune complexes, in the pathogenesis of Graves' ophthalmopathy appears to have been excluded by these findings.