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Biomedical subjects

C Stover

Publications and source records attributed to C Stover.

23 records · Page 2Linked to original sources
PubMed1991

Relationship of eye muscle antibodies with HLA phenotypes and thyroid-stimulating immunoglobulins in endocrine orbitopathy.

The relationship between endocrine orbitopathy and Graves' hyperthyroidism is still not clarified. The purpose of this study was to elucidate the incidence of eye muscle antibodies and the relationship with HLA phenotypes and thyroid antibodies in 65 patients with endocrine orbitopathy classes 1-5. Both bovine and abdominal muscles were used as antigens in ELISA systems in which IgG and IgM antibodies were assayed. Before starting the immunosuppressant therapy, 46/65 patients (71%) showed a positive result for eye muscle antibodies. Those patients with an active disease had such antibodies more frequently. Where the ophthalmopathy was of recent onset IgM antibodies were found, whereas patients with chronic disease were mostly IgG-Ab positive. No association was found either with HLA phenotypes (B8, DR3) or with antibodies directed against thyroglobulin, thyroid microsomes, and the TSH receptor measured as thyroid-stimulating immunoglobulins. Furthermore, there was no correlation between ophthalmopathy class and optic muscle antibody-binding activity. There was no relation between the degree of exophthalmos and eye muscle, thyroid-stimulating, antithyroglobulin, or antithyroid microsomal antibodies. These results suggest that, although very closely related, endocrine orbitopathy and Graves' hyperthyroidism are separate, organ-specific autoimmune diseases.

Adolescent↗
PubMed1988

Expression and characterization of a functional human insulin-like growth factor I receptor.

Stable transfectants of Chinese hamster ovary (CHO) cells were developed that expressed the protein encoded by a human insulin-like growth factor I (IGF-I) receptor cDNA. The transfected cells expressed approximately 25,000 high affinity receptors for IGF-I (apparent Kd of 1.5 X 10(-9) M), whereas the parental CHO cells expressed only 5,000 receptors per cell (apparent Kd of 1.3 X 10(-9) M). A monoclonal antibody specific for the human IGF-I receptor inhibited IGF-I binding to the expressed receptor and immunoprecipitated polypeptides of apparent Mr values approximately 135,000 and 95,000 from metabolically labeled lysates of the transfected cells but not control cells. The expressed receptor was also capable of binding IGF-II with high affinity (Kd approximately 3 nM) and weakly recognized insulin (with about 1% the potency of IGF-I). The human IGF-I receptor expressed in these cells was capable of IGF-I-stimulated autophosphorylation and phosphorylation of endogenous substrates in the intact cell. This receptor also mediated IGF-I-stimulated glucose uptake, glycogen synthesis, and DNA synthesis. The extent of these responses was comparable to the stimulation by insulin of the same biological responses in CHO cells expressing the human insulin receptor. These results indicate that the isolated cDNA encodes a functional IGF-I receptor and that there are no inherent differences in the abilities of the insulin and IGF-I receptors to mediate rapid and long term biological responses when expressed in the same cell type. The high affinity of this receptor for IGF-II also suggests that it may be important in mediating biological responses to IGF-II as well as IGF-I.

Animals↗
PubMed1987

Interactions of the receptor for insulin-like growth factor II with mannose-6-phosphate and antibodies to the mannose-6-phosphate receptor.

Recently, the sequence of the human receptor for insulin-like growth factor II (IGF-II) was found to be 80% identical [Morgan et al., (1987) Nature 329, 301-307] to the sequence of a partial clone of the bovine cation-independent mannose-6-phosphate receptor [Lobel et al., (1987) Proc. Natl. Acad. Sci. USA 84, 2233-2237]. In the present study, the purified receptor for insulin-like growth factor II (IGF-II) was found to react with two different polyclonal antibodies to the purified mannose-6-phosphate receptor. Moreover, mannose-6-phosphate was found to stimulate the binding of labeled IGF-II to the IGF-II receptor by two-fold. This effect had the same specificity and affinity as the reported binding of mannose-6-phosphate to its receptor; mannose-1-phosphate and mannose had no effect on the binding of labeled IGF-II to its receptor, and the half-maximally effective concentration of mannose-6-phosphate was 0.3 mM. Also, mannose-6-phosphate did not affect labeled IGF-II binding to the insulin receptor. These results support the hypothesis that a single protein of Mr-250,000 binds both IGF-II and mannose-6-phosphate. Furthermore, they indicate that mannose-6-phosphate can modulate the interaction of IGF-II to its receptor.

Carrier Proteins↗