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Biomedical subjects

Keiichi Kamijo

Publications and source records attributed to Keiichi Kamijo.

5 recordsLinked to original sources
PubMed2005

Clinical evaluation of 3rd generation assay for thyrotropin receptor antibodies: the M22-biotin-based ELISA initiated by Smith.

Recently a new procedure for measuring serum TSH receptor (TSHR) autoantibody (TRAb) was reported by Smith et al. in which the autoantibodies inhibit binding of a human monoclonal thyroid stimulating antibody M22 (labeled with biotin) to TSHR-coated ELISA plate wells (pTRAb(3rd) assay). The aim of this study was to compare the performance of pTRAb(3rd) assay with pTRAb(2nd) assay based on inhibition of TSH-biotin binding to TSHR-coated ELISA plate wells. In addition, we evaluated the applicability of TRAb3rd assay to discriminate between untreated Graves' disease (GD) and painless thyroiditis (PT). Analysis of sera from 230 healthy controls indicated that only 1 (0.43%) gave inhibition of M22-binding values of greater than 15% (32.8% inhibition). To define the clinical cut-off point for a positive serum with autoantibodies to the TSHR, we performed receiver operating characteristic curve of the data from 244 untreated GD and three different control groups for pTRAb(3rd) assay. With a sensitivity of 99.6% at a cut-off of 14.5%, 22.0% and 22.0% inhibition of M22 binding, the specificity of healthy controls without PT, with PT and with PT excluding postpartum PT and PT during remission of GD was 99.6%, 96.6% and 97.5%, respectively. The pTRAb(3rd) assay was closely correlated to pTRAb(2nd) assay in the 244 untreated Graves' sera (r = 0.911). The pTRAb(3rd) assay detected 243 of 244 (99.6%) untreated GD, whereas 9.2% of PT and 6.7% of the subacute thyroiditis (SAT) were detectable. In contrast, pTRAb (2nd) assay detected 242 of 244 (99.2%) Graves' same sera, while 16.8 % from PT's same sera and 13.3% from SAT were detectable. In conclusion, pTRAb(3rd) assay has significantly (p = 0.0026) superior diagnostic accuracy for GD and PT, compared to that of pTRAb(2nd) assay.

Adolescent↗
PubMed2003

TSH-receptor antibody measurement in patients with various thyrotoxicosis and Hashimoto's thyroiditis: a comparison of two two-step assays, coated plate ELISA using porcine TSH-receptor and coated tube radioassay using human recombinant TSH-receptor.

The aim of this study was to compare two two-step assays, a new coated plate (CP) ELISA assay (TRAb ELISA) using purified porcine TSH-receptors (pTSH-R) and a coated tube assay (CT) using recombinant human TSH-receptors (hTSH-R) (DYNO(R) test TRAK human). The same serum samples were used for the determination by both assays in patients with 100 untreated Graves' disease (GD), 30 silent thyroiditis (ST), 10 subacute thyroiditis (SAT) and 87 Hashimoto's thyroiditis (HT). In sera from patients with untreated GD, pTBII and hTBII were positive in nearly all cases except the same one, whereas the thirty sera from the ST had positive values of pTBII in one case and of hTBII in 4 cases. In the one ST case of both pTBII and hTBII positive, hyperthyroidism developed following ST, although the remaining ST cases including the three hTBII-positive cases were not followed by hyperthyroidism after ST attack. A positive value of hTBII was observed in one of 10 patients with SAT, whereas none of them was pTBII positive. In the 87 patients with HT, positive values of pTBII were recognized in 9 patients, whereas hTBII is positive in 10 patients. Serum TSAb and TSBAb activities were analyzed in the hTBII positive 7 patients. As a result, TSAb was all positive except one and TSBAb positive in 4 cases. Since there is no significant difference in the sensitivity and specificity between the two assays in the differentiation of thyrotoxicosis as well as the frequency of finding positive values in patients with HT, it is reasonable to conclude that the clear advantage of sensitivity for clinical application in the new CP and CT assays may be derived from the coated plate or coated tube assay itself, which probably excludes the effect of anti-TSH antibodies and HAMA, and is unrelated to the use of human or porcine TSH-receptors.

Adult↗
PubMedDate not supplied

Sensitive thyroid-stimulating antibody assay with high concentrations of polyethylene glycol for the diagnosis of Graves' disease.

The aim of the present study was to determine the usefulness of a newly developed thyroid-stimulating antibody (TSAb) assay. We developed a highly sensitive TSAb (sTSAb) assay with 22.5% polyethylene glycol-precipitated crude IgG. The thyroid-stimulating hormone (TSH) receptor antibody (TRAb) causes Graves' disease and TRAb has been measured as TSH-binding inhibitor immunoglobulin (TBII) and thyroid-stimulating antibody (TSAb). The TSAb stimulates the thyroid glands and causes hyperthyroidism. In addition to investigating the usefulness of the newly developed sTSAb assay, we also investigated the frequencies of positive TRAb in thyrotoxic patients with subacute thyroiditis, painless thyroiditis or a solitary toxic nodule. We studied 700 untreated Graves' patients with hyperthyroidism and 923 normal controls. We also studied thyrotoxic patients with subacute thyroiditis, painless thyroiditis or a solitary toxic nodule. Conventional TSAb (cTSAb) and sTSAb were measured as TSAb, whereas porcine TBII (pTBII) and human recombinant TBII (hTBII) were measured as TBII. Levels of cTSAb and sTSAb were determined in 923 normal controls and 629 untreated Graves' patients and cTSAb and sTSAb were found to be normally distributed in normal controls, but not in untreated Graves' patients. Receiver operating characteristic (ROC) curve analysis demonstrated that cTSAb and sTSAb had high sensitivity and specificity for Graves' disease. Of the patients investigated, 96.5% of untreated Graves' patients were positive for sTSAb and/or pTBII. Some untreated Graves' patients who were negative for cTSAb were positive for sTSAb. Paired determinations of cTSAb and sTSAb were performed in 146 untreated Graves' patients. A positive correlation was found between cTSAb and sTSAb. Titres of sTSAb were higher than those of cTSAb and sTSAb had high sensitivity. Of the 35 untreated Graves' hyperthyroid patients who were negative for cTSAb, 18 (51%) were positive for sTSAb. Of the 36 untreated Graves' patients who were negative for hTBII, nine (25%) were positive for sTSAb. Some untreated Graves' patients who were negative for cTSAb were positive for sTSAb and some who were negative for hTBII and pTBII were positive for sTSAb. 5. Some thyrotoxic patients with subacute thyroiditis or painless thyroiditis were positive for TRAb. However, the frequency of TRAb-positive patients was low in this group. None of the patients with a solitary toxic nodule was positive for TRAb. In conclusion, sTSAb had higher sensitivity than cTSAb. Graves' patients who were cTSAb negative and hTBII negative could be sTSAb positive. The sTSAb indicates TSAb activity, but pTBII and hTBII do not necessarily do so. We recommended that the sTSAb is used in Graves' patients.

Adult↗