We have investigated the membrane-binding properties of fetal liver cells (FLC) and developed an ... more We have investigated the membrane-binding properties of fetal liver cells (FLC) and developed an assay to quantitate circulating immune complexes (CIC) based on complement (C) receptor binding on FLC. Both binding and blocking studies identified FLC membrane receptors for IgG-Fc, C, and antifetal antibodies (FL-Ab), but not IgG F(ab)′2. Fc binding of IgG or aggregated human IgG (AHG) was relatively weak, with an association constant of 1.5×107 l/mol. In contrast, there was a six- to seven-fold increase in binding of AHG by C receptors, with an association constant of 108 l/mol. A simple and sensitive procedure for detecting CIC in the sera of patients with various disease states has been developed by the use of C receptors on FLC. Reference to an AHG standard curve permits quantitation of CIC in micrograms of AHG equivalent per milliliter of serum. Clinical evaluation in patients with active collagen vascular disease and in cancer patients confirmed the reliability, specificity of binding, and sensitivity of the FLC method. Although there was overall agreement with the Raji cell method for CIC detection, FLC-RIA quantiation of CIC was found to be more sensitive than the Raji cell assay. Other discrepancies could be explained by differing sensitivity to CIC size.
Since serum N-acetylneuraminic acid (NANA) can serve as a relatively sensitive monitor of tumor b... more Since serum N-acetylneuraminic acid (NANA) can serve as a relatively sensitive monitor of tumor burden, we wished to examine the relationship of NANA to other suggested prognostic factors for malignant melanoma. Eligible patients included 151 patients with stage-l disease and 10 with stage-ll regional lymphatic extension. A proportional hazards model was used to examine nine factors, of which five were not significant predictors of recurrence: age, sex, primary site, tumor diameter, and stage. Significant predictors included: measured depth p=7×10−7; anatomic depth (Clark level), p=7×10−4; NANA, p=0.003; and growth pattern (superficial spreading vs nodular), p=0.01. However, on multivariate analysis only two predictors were independent; measured depth and NANA. The latter could not be explained by non-specific factors. The data were examined to define optimal test values for assignment of risk. According to this model, patients with lesions >l.75 mm and NANA <2μmol/ml have a more than 12-fold greater risk of recurrence by 2 years than those with lesions ⩽1.75 mm and NANA ⩽2 μmol/ml.
We have investigated the membrane-binding properties of fetal liver cells (FLC) and developed an ... more We have investigated the membrane-binding properties of fetal liver cells (FLC) and developed an assay to quantitate circulating immune complexes (CIC) based on complement (C) receptor binding on FLC. Both binding and blocking studies identified FLC membrane receptors for IgG-Fc, C, and antifetal antibodies (FL-Ab), but not IgG F(ab)′2. Fc binding of IgG or aggregated human IgG (AHG) was relatively weak, with an association constant of 1.5×107 l/mol. In contrast, there was a six- to seven-fold increase in binding of AHG by C receptors, with an association constant of 108 l/mol. A simple and sensitive procedure for detecting CIC in the sera of patients with various disease states has been developed by the use of C receptors on FLC. Reference to an AHG standard curve permits quantitation of CIC in micrograms of AHG equivalent per milliliter of serum. Clinical evaluation in patients with active collagen vascular disease and in cancer patients confirmed the reliability, specificity of binding, and sensitivity of the FLC method. Although there was overall agreement with the Raji cell method for CIC detection, FLC-RIA quantiation of CIC was found to be more sensitive than the Raji cell assay. Other discrepancies could be explained by differing sensitivity to CIC size.
Since serum N-acetylneuraminic acid (NANA) can serve as a relatively sensitive monitor of tumor b... more Since serum N-acetylneuraminic acid (NANA) can serve as a relatively sensitive monitor of tumor burden, we wished to examine the relationship of NANA to other suggested prognostic factors for malignant melanoma. Eligible patients included 151 patients with stage-l disease and 10 with stage-ll regional lymphatic extension. A proportional hazards model was used to examine nine factors, of which five were not significant predictors of recurrence: age, sex, primary site, tumor diameter, and stage. Significant predictors included: measured depth p=7×10−7; anatomic depth (Clark level), p=7×10−4; NANA, p=0.003; and growth pattern (superficial spreading vs nodular), p=0.01. However, on multivariate analysis only two predictors were independent; measured depth and NANA. The latter could not be explained by non-specific factors. The data were examined to define optimal test values for assignment of risk. According to this model, patients with lesions >l.75 mm and NANA <2μmol/ml have a more than 12-fold greater risk of recurrence by 2 years than those with lesions ⩽1.75 mm and NANA ⩽2 μmol/ml.
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