Monoclonal antibodies to the rabbit liver growth hormone receptor: production and characterization

Monoclonal antibodies to the GH receptor (GHR) have been produced by the application of hybridoma technology to splenic lymphocytes from BALB/C mice immunized with a human (hGH) affinity purified preparation of rabbit liver GHR. Primary screening of 384 wells yielded 4 antibodies able to immunoprecipitate [125I]iodo-hGH complexes with purified GHR and one able to inhibit binding of [125I]iodoovine GH ([125I]iodo-oGH) to rabbit liver microsomes. These cells were cloned and grown as ascitic tumors with loss of 1 of the 4 precipitators. Ascitic fluids contained monoclonal antibodies of high titer (inhibitor and 2 precipitators, 1:2.0 x 105; one precipitator, 1:2.0 x 104) and high affinity (precipitators, 2.5–6.0 x 109M–1; inhibitor, high affinity component, 6.4 x 1010 M–1), which were isotyped as IgGlK and IgG2aK (1 precipitator). These antibodies did not cross-react with rabbit insulin or PRL receptors in the appropriate receptor assays and did not possess antihormone activity. Binding of [125I]iodo-MAb7, the inhibitory antibody, was totally blocked by the addition of excess unlabeled oGH or hGH, although these hormones had no effect on binding of the 125I-labeled precipitators. Scatchard analysis of [125I]iodo-oGH binding in the presence of MAb7 showed decreased binding by loss of sites rather than affinity. Antibody dilution curves and Scat-chard plots for MAb7 binding provided evidence for two types of GHR in the rabbit liver, in accord with previously published data based on hormone binding studies. All precipitating antibodies gave an enhancement of [125I] iodo-oGH binding with purified receptor (up to 360% of polyethylene glycol-precipitated control), but only minimal enhancement with solubilized microsomal membranes. This enhancement was shown to be due to an increase in receptor number rather than affinity. After examining a number of hypotheses, we concluded that the enhancement was an artifact resulting from a nonpolyethylene glycol-precipitable species of GHR which could be totally precipitated by the monoclonal antibodies. We have produced and characterized four monoclonal antibodies to the GHR which will be of value in characterizing the structure and function of this recepto

Manipulation of mental models of anatomy in interventional radiology and its consequences for design of human–computer interaction

Interventional radiology procedures require extensive cognitive processing from the physician. A set of these cognitive functions are aimed to be replaced by technology in order to reduce the cognitive load. However, limited knowledge is available regarding mental processes in interventional radiology. This research focuses on identifying mental model–related processes, in particular during percutaneous procedures, useful to improve image guidance during interventions. Ethnographic studies and a prototype-based study were conducted in order to perform a task analysis and to identify working strategies and cognitive processes. Data were compared to theories from visual imagery. The results indicate a high level of complexity of mental model construction and manipulation, in particular when mentally comparing mental model knowledge with radiology images on screen (e.g., to steer a needle correctly). Regarding current interface support, most difficult is the interpretation and selection of oblique views. New interface principles are needed to bring cognitive demands within reasonable human range, and also accompanying cognitive work strategies should be developed.Design EngineeringIndustrial Design Engineerin