Use of Chinese hamster ovary cell lines transfected with cloned human thyrotropin receptor for the measurement of thyroid-stimulating antibodies: Advantages and difficulties
Laboratoire de Génétique Moléculaire et Hormonologie, CHU de Pontchaillou, rue H. Le Guilloux, 35043, Rennes, France.Clinica Chimica Acta (Impact Factor: 2.82). 01/2000; 291(1):67-81. DOI: 10.1016/S0009-8981(99)00198-9
We compared the activities of thyroid-stimulating antibodies (TSAb) as measured with two cell lines (JP26 and JP26/26) transfected with cloned human thyrotropin (TSH) receptor and the values for TSAb measured on human thyrocytes cultures. Sera were obtained from patients with Graves' disease, before, during and after therapy with carbimazole (1-methyl-2-thio-3-carbethoxyimidazole). The activities of TSAb performed with the three assays correlated significantly. The TSAb technique using JP26/26 cells was as sensitive as the method performed on human thyrocyte cultures since positive TSAb values were found in 45 out of 47 (95.7%) newly diagnosed patients, in 100% of patients who relapsed after drug withdrawal and in none in remission. When the JP26 cell line was used, sensitivity decreased as the detection rate was only 53.2 and 55.5% before treatment and in case of relapse, respectively. The TSH receptors analysis showed a receptor density two times higher for JP26/26 than for JP26. JP26/26 cells provide similar diagnostic information on human thyrocytes in patients with Graves' disease. Moreover with these cells, the procedure for cell culture is less cumbersome and precision is better. However, rigorous culture conditions are required to maintain TSH receptor expression in transfected cells.
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ABSTRACT: An adaptive comb filtering method, which was initially investigated by Frazier et al.  for the enhancement of degraded speech due to additive noise, is applied for estimating vocal noise generated at the glottis due to pathological changes of the vocal folds. In applying the method, special emphasis is placed on the accurate determination of pitch period durations. The amount of estimated vocal noise is quantified by a novel acoustic measure, normalized noise energy(NNE). Experiments with vowel samples spoken by 64 normal control subjects and 50 patients with glottic cancer have shown that the NNE is useful for the distinction between normal and pathological voice status.
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ABSTRACT: First, to evaluate the performance level of a new TSH binding inhibitory antibody assay using human recombinant TSH receptors (h-TBII) in comparison with a thyroid stimulating antibody (TSAb) bioassay performed before, at the end of treatment (18 months) and after antithyroid drug withdrawal in Graves' disease patients; second, to assess the accuracy with which h-TBII levels could predict relapse and remission. Retrospective study on serum samples of Graves' disease patients treated by antithyroid drugs for 18 months. Serum samples from 140 patients (27 men and 113 women; median age 42 years) with recent onset hyperthyroidism due to Graves' disease were retrospectively tested for h-TBII at diagnosis, at 18 months and for 76 of them 6, 12, 24 and 36 months after drug withdrawal or at relapse. TSAb were also evaluated at each time. Thyroid blocking antibodies (TBAb) were measured in sera positive for h-TBII and negative for TSAb. h-TBII levels were measured with a radioreceptor assay using the human recombinant TSH receptor (DYNOtest TRAK human from B.R.A.H.M.S. Diagnostica, Berlin, Germany). TSAb and TBAb levels were assayed in thyrocyte cultures. At diagnosis, high levels of h-TBII were found in 138 of 140 patients with Graves' disease (98.6%). High TSAb values were also detected in the same 138 patients. The h-TBII and TSAb values were significantly correlated (r = 0.582, p < 0.0001). At 18 months, h-TBII were found in 48 of the 140 patients (34%) and TSAb in 43 patients (31%). The h-TBII and TSAb values were significantly correlated (r = 0.618, p < 0.0001) and fell significantly between diagnosis and 18 months (Z = - 9.84, p < 0.0001 and Z = - 9.19, p < 0.0001). TBAb were found in two of the 11 sera positive for h-TBII and negative for TSAb. At diagnosis, the median levels of h-TBII and TSAb were not significantly different between the patients who relapsed within the 3 years after the withdrawal of treatment (n = 60) and those who did not (n = 80) (Z = - 1.1, ns; Z = - 0.216, ns). At 18 months, the prevalences of h-TBII and TSAb were significantly increased in patients who relapsed compared to those who remained in remission at 3 years (60% vs. 15%, chi2 = 30.8, p < 0.0001 and 55% vs. 13%, chi2 = 29.1, p < 0.0001, respectively). h-TBII and TSAb median levels were also significantly increased in patients who relapsed compared to the others (Z = - 4,8, p < 0.0001; Z = - 3,01, P < 0.005). Among the 60 patients who relapsed, 36 (60%) displayed h-TBII and 33 (55%) TSAb at 18 months. The majority of patients who relapsed during the 2 years following the end of treatment, in contrast to those who relapsed later, were positive for h-TBII (67% vs. 27%, chi2 = 6.01, p = 0.035). Seventeen of the 18 tested patients who relapsed were negative for h-TBII at 18 months, were then positive for h-TBII at the time of relapse, whereas 15 of them were still negative, 6-12 months before the relapse. Among the 80 patients who remained in remission at 3 years, only 10 (13%) displayed TSAb and 12 (15%) h-TBII at 18 months. In 10 of these 12 patients who were further evaluated for h-TBII positivity, h-TBII fell to control levels during the 3 years following the end of treatment. The new h-TBII assay is a simple and rapid method with a performance level similar to that of TSAb determination. Its sensitivity is close to 100% at diagnosis. In the whole group, TBII level analysis is relevant as a predictor for short time relapse. However, some of the patients are "misclassified", due to the inter-individual variability in the time course of h-TBII activity. Our results confirm that, in addition to h-TBII, even when measured with a highly sensitive test, the concomitant analysis of other clinical and/or biological parameters is necessary to improve the prediction of treatment outcome.
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ABSTRACT: Subclinical hypothyroidism occurs in a number of children with Down's syndrome (DS). The reason for the mildly elevated plasma thyrotropin (TSH) concentrations is not known. The present study investigated whether decreased TSH bioactivity plays a role in this phenomenon. A retrospective study of plasma specimens from DS children with mildly elevated plasma TSH concentrations and thyroid hormone levels within the reference range, using a TSH receptor-adenylate cyclase mediated bioassay. Strain JP26 Chinese hamster ovary (CHO) cells, stable transfected with the human TSH receptor, were incubated with unfractionated plasma (1/10 diluted in hypotonic incubation medium) of 10 DS children with subclinical hypothyroidism and nine euthyroid children with insulin-dependent diabetes mellitus as controls. cAMP released in the incubation medium was measured by RIA. Mock-transfected CHO cells were used to correct for non-specific CHO response. WHO Second International Reference Preparation of human TSH was dissolved and diluted in pooled normal human plasma and simultaneously bioassayed to match patient and control results. Plasma TSH levels were slightly increased in DS (mean +/- S.D., 6.5+/-1.3 mU/l, reference range 0.4-4.0 mU/l). Plasma TSH levels for controls (1.3+/-0.4 mU/l) were within the reference range. Plasma thyroid hormone levels in patients and controls were normal, plasma TSH binding inhibitory immunoglobulin and thyroid peroxidase antibodies were negative. cAMP levels (corrected for non-specific CHO response) in DS patients (18.4+/-3.9 pmol/well) and in controls (14.3+/-1.3 pmol/well) did not significantly differ from cAMP levels generated by patient-TSH equivalent TSH standards (16.3+/-0.9 pmol/well). The present results demonstrate normal TSH bioactivity in plasma of DS children, indicating that subclinical hypothyroidism in these patients is of primary (thyroidal) origin.
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