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Biomedical subjects

B Y Cho

Publications and source records attributed to B Y Cho.

68 records · Page 4Linked to original sources
PubMed1989

Pathogenetic role of thyrotropin receptor antibody in the development of hyperthyroidism following primary hypothyroidism.

The authors measured thyrotropin binding inhibitory immunoglobulin (TBII), thyroid stimulating antibody (TSAb), and thyroid stimulation blocking antibody (TSBAb) sequentially in patients who developed hyperthyroidism following primary hypothyroidism, and compared changes in these various functional parameters of thyrotropin receptor antibody (TRAb) with clinical manifestations, in order to investigate the role of TRAb in the development of hyperthyroidism following primary hypothyroidism. In a patient with goitrous chronic thyroiditis, TBII, TSAb and TSBAb were not detected at the initial hypothyroid phase. But with appearance of TBII and TSAb, the patient developed hyperthyroidism. In a patient with primary nongoitrous myxedema, initially high TBII and TSBAb were detected without TSAb activity. His TSBAb disappeared and TSAb appeared with development of goiter growth and hyperthyroidism. These two mechanisms, that is, appearance of previously absent TSAb and conversion of TSBAb to TSAb, might play a causative role in the development of hyperthyroidism following primary hypothyroidism. These phenomena might be evidence that Graves' disease, chronic thyroiditis, and primary nongoitrous myxedema are on a continuing spectrum of a common syndrome sharing similar pathophysiology, at least with respect to TRAb.

Adult↗
PubMed1989

Changes in the properties of the thyrotropin receptor antibody in patients with Graves' disease after radioiodine treatment.

We investigated the effect of a single dose of 131I upon thyrotropin receptor antibodies (TRAb) in 21 patients with Graves' disease. The thyrotropin receptor antibodies were assessed by parallel measurements of thyrotropin binding inhibitor immunoglobulin (TBII), thyroid stimulating antibody (TSAb), and thyroid stimulation blocking antibody (TSBAb) in serum by radioreceptor assay, stimulation of adenylate cyclase and inhibition of TSH-stimulated adenylate cyclase activation in FRTL-5 cells, respectively. Prior to radioiodine treatment TBII was detected in all 21 patients and TSAB in 19 patients. After radioiodine treatment TBII activities did not change during 12 months observation period, but in eight patients TSAb activities gradually decreased and were undetectable at the end of a 12 month observation period. Persistence of TSAb was not associated with clinical outcome. Eight patients developed hypothyroidism within 1 year after radioiodine treatment. Three of the hypothyroid patients developed TSBAb, and the appearance of TSBAb coincided with the development of hypothyroidism. These results suggest that TSBAb might develop after radioiodine treatment in a minority of patients with Graves' disease, and that the appearance of TSBAb, in addition to radiation induced thyroid destruction, might be involved in the development of hypothyroidism following radioiodine treatment.

Adolescent↗
PubMed1989

Anti-bovine TSH antibodies in patients with Graves' disease and primary myxedema.

Three patients with Graves' disease and one patients with primary myxedema had serum TSH-binding immunoglobulins of high affinity detected by the TSH binding inhibition immunoglobulin (TBII) assay. These IgGs bound 61%, 33%, 60% and 53% of radiolabeled TSH, respectively, higher than the maximal specific binding (25%) in the TBII assay. Such binding was detected even in the absence of TSH receptor with only small differences in the precipitable radioactivity (61%, 28%, 61%, 54%, respectively, in comparison with the assay non-specific binding 11.3%). The 125I-bTSH binding of IgGs was competitively inhibited by the addition of bTSH, but not inhibited by hTSH. Moreover IgG binding to bTSH was not inhibited by the addition of serial dilutions of TBII positive pooled Graves' IgG (0.1-10 mg/ml) from different untreated patients. The titers of these TSH binding antibodies were not changed during the treatment of Graves' disease. Following guinea pig fat cell membrane receptor purification, the IgG of one patient with Graves' disease revealed TBII activity of 43.7% inhibition of 125I-bTSH binding to the TSH receptor without binding activity of 125I-bTSH in the absence of the TSH receptor. These studies suggest that anti-TSH antibodies and TSH receptor antibodies are present independent of one another in sera of some patients with autoimmune thyroid diseases and anti-TSH antibodies result in false TBII assay results.

Adult↗
PubMed1988

Transient neonatal hypothyroidism due to transplacental transfer of maternal immunoglobulins that inhibit TSH binding, TSH-induced cAMP increase and cell growth.

Transient neonatal hypothyroidism due to transplacental transfer of maternal blocking type TSH receptor antibodies (TRAb) was found in a baby born to a 27-yr-old mother, who had been receiving thyroxine medication for primary myxedema. Maternal IgG inhibited radiolabelled TSH binding to its receptor (TBII), TSH-stimulated thyroid adenylate cyclase (AC) activation (TSII) and TSH-stimulated 3H-thymidine uptake (TGII) in cultured rat thyroid cells (FRTL-5). At birth, the baby's IgG showed similar activities to maternal IgG but all these activities decreased gradually, and disappeared from her serum within 12 weeks of age. In the baby, initially nonvisualized thyroid was clearly visualized on 99 m-Tc thyroid scintigraphy when all these blocking activities disappeared, TSII and TGII being decreased more slowly than TBII, and the baby remained euthyroid after discontinuation of thyroxine. This study suggests that such IgGs induced hypothyroidism and thyroid atrophy in the mother and were responsible for transient neonatal hypothyroidism in the baby.

Adult↗
PubMed1988

Computerized quality control of radioimmunoassay in Korea.

Automated data processing and quality control of radioimmunoassays offer not only increased speed but also a more thorough and statistically rigorous analysis of results. An external quality assessment scheme for serum thyroxine, triiodothyronine and thyroid stimulating hormone (TSH) assays was performed in five nuclear medicine laboratories in Korea to compare with the assay performances of the World Health Organization Radioimmunoassay Program. The required radioimmunoassay kits were supplied through the International Atomic Energy Agency (IAEA). We have determined the weighted root mean squared error, and variance ratio as the indices of standard curve and also the average batch coefficient of variation (ABCV) as the parameters of response error relationship curve and precision profile. There was a good fit for the triiodothyronine assay, but 3 of 5 laboratories showed possible bad fit in the T4 and TSH assay systems. The ABCV was less than 5 percent for the T3 and T4 assay system, however for the TSH system, only 1 laboratory showed the ABCV value of less than 5 percent. We have also calculated the within batch variation (drift) and between laboratory variations.

Electronic Data Processing↗
PubMed1987

HLA and Graves' disease in Koreans.

The HLA-A, B, C and DR antigen distribution in 128 Korean patients with Graves' disease was compared with that in 220 controls. The frequency of HLA-B13, DR5 and DRw8 (relative risk 3.8, 4.4, and 2.3, respectively) was significantly increased in patients with Graves' disease. There was no significant correlation between the presence of these HLA antigens and the clinical features.

Female↗
PubMedDate not supplied

Immunodetection approaches and high-performance immunoaffinity chromatography for an analogue of bovine growth hormone releasing factor at trace levels.

An indirect detection method using high-performance immunoaffinity chromatography (HPIAC) was used to measure low levels of an analogue of bovine Growth Hormone Releasing Factor (bGHRF). An antibody (Ab) labelled with alkaline phosphate (ALP) was incubated with the bGHRF analogue to perform a complex between the antigen (Ag) and the antibody-enzyme (Ab-En) conjugate. The complex was then injected onto a cartridge containing an immobilized Ag affinity support. Species which were not recognized by the affinity cartridge, i.e. eluted, were then directly combined, via a connecting tee, with a buffer containing a substrate. Incubation proceeded on-line, inside a knitted reactor coil, under conditions of constant flow. The subsequent generation of a fluorescently active substrate product was detected by conventional means. The assay described has a linear response region from 1.0 to 25 ng of the bGHRF analogue and a limit of detection of 0.60 ng (1.7 x 10(2) femtomole, 30 p.p.b.). This approach was compared against a method in the antigen/Ab-En complex was injected onto a immobilized Ab affinity cartridge to form an antibody-antigen conjugate sandwich and subsequent stop-flow incubation with substrate.

Animals↗
PubMedDate not supplied

Spontaneous hypoglycemia and insulin autoantibodies in a patient with Graves' disease.

A 31-year-old woman with Graves' disease developed fasting hypoglycemia after treatment for 3 weeks with methimazole. Although the patient had not received exogenous insulin, high titers of insulin autoantibodies were found in serum and large amounts of total and free insulin (1550 and 82 microU/ml, respectively) and C-peptide reactivity (CPR, 22 ng/ml) were detected in serum. After glucose loading, blood glucose and total insulin levels increased abnormally. The immunoglobulin class of the autoantibodies was IgG and the light chains were of the kappa type. The titers of insulin autoantibodies, elevated serum total and free insulin, and CPR levels decreased gradually, but insulin autoantibodies and elevated insulin levels were still present in the serum 8 months after the episode of hypoglycemia. These findings suggest that the patient's fasting hypoglycemia was due to excess free insulin released from antibody-bound insulin, and that methimazole might play a role in the initiation of production of insulin autoantibodies.

Adult↗