Tc-99m dimercaptosuccinic acid(DMSA) renal scintigraphy in patients with acute pyelonephritis.

OBJECTIVES: Recently, several authors reported that Tc-99m DMSA renal scan frequently showed cortical defects of the involved kidneys even in the patients with acute pyelonephritis who did not show abnormal findings in the ultrasonography and intravenous pyelography (IVP). METHODS: In order to evaluate the utilities of Tc-99m DMSA renal scan and the clinical meaning of cortical defects in the Tc-99m DMSA renal scan of the patients with acute pyelonephritis, ninety two patients with acute pyelonephritis, from March 1991 to February 1994 in Chungnam National University Hospital(CNUH), were included in this study. Patients were subdivided as Group A:Patients showing normal Tc-99m DMSA renal scan (n = 42) and Group B:Patients with definite cortical defects on the Tc-99m DMSA renal scan (n = 50). We compared clinical characteristics such as age and sex, recurrency, duration of fever, bacterial culture study, incidence of renal insufficiency and the results of renal ultrasonography and intravenous pyelography between the two groups. RESULTS: Fifty four percents of 92 patients with acute pyelonephritis showed a significantly longer febrile period after admission, higher positive rates on the urine and blood culture studies and higher incidence of renal insufficiency than those of the Group A patients. Sixty nine percents of Group B patients showed normal results in ultrasonography or IVP study. CONCLUSIONS: Tc-99m DMSA renal scan was a more sensitive imaging test than ultrasonography in kidneys and IVP to detect pyelonephritis lesions and may be useful to predict the patient group with a severe disease course. These patients may need more careful management and further studies to evaluate the possibility of complications.

Negative correlation between the conversion of thyrotropin receptor-bound blocking type thyrotropin receptor antibody to the stimulating type by anti-human IgG antibodies and the biological activity of blocking type thyrotropin receptor antibody.

It has been reported that receptor-bound blocking type TSH receptor antibody (TRAb) can be converted to the stimulating type by anti-human IgG antibodies. To evaluate the relationship between the conversion of receptor-bound blocking type TRAb to the stimulating type and the biological activity of blocking type TRAb, we compared converting activities of blocking type TRAb from 10 patients with primary nongoitrous hypothyroidism with both the doses of blocking type TRAb which show 50% inhibition of 125I-bTSH binding to the TSH receptor and those which show 50% inhibition of TSH-stimulated cAMP production in cultured rat thyroid cells (FRTL-5). The additions of anti-human IgG antibody to FRTL-5 cell-bound blocking IgGs resulted in the increase in cAMP production in a dose-dependent manner and the converting activities (percent increase of cAMP production) also depended on the doses of blocking IgGs. The converting activities were significantly correlated with the doses of blocking IgGs which showed 50% inhibition of 125I-bTSH binding to the TSH receptor (r = 0.71, p = 0.011). And these converting activities were also significantly correlated with the doses of blocking IgGs which showed 50% inhibition of TSH-stimulated cAMP increase (r = 0.81, p = 0.002), and were negatively correlated with thyroid stimulation blocking antibody activities (r = 0.58, p = 0.02). We have demonstrated that all cell-bound blocking type TRAb were converted to the stimulating type by anti-human IgG antibody and the degree of conversion was negatively correlated with the biological activity of blocking type TRAb.(ABSTRACT TRUNCATED AT 250 WORDS)

The IgG subclass distribution of TSH receptor blocking antibodies in primary hypothyroidism.

OBJECTIVE: TSH receptor stimulating antibodies are restricted to the IgG1 subclass suggesting an oligoclonal origin. We wished to determine whether thyroid stimulation blocking antibodies, which also bind to the TSH receptor but may cause hypothyroidism, are similarly IgG subclass restricted. DESIGN: Sera containing TSH receptor blocking antibody activity were separated into IgG subclasses by negative depletion of all other subclasses on affinity columns of subclass-specific monoclonal antibodies or protein A as appropriate. PATIENTS: Eleven patients from two centres were studied. All had autoimmune hypothyroidism and TSH receptor blocking antibodies but no thyroid stimulating antibodies. MEASUREMENTS: TSH receptor blocking antibody activity was measured by assessing inhibition of TSH-stimulated cAMP production by human thyroid cells (five Israeli samples) or by the FRTL-5 rat thyroid cell line (six Korean samples). RESULTS: IgG1 was the most important subclass containing TSH receptor blocking antibody activity but complete restriction to this subclass was never seen. Clearly detectable activity was found in the IgG2 subclass in eight patients, in the IgG3 subclass in three patients, and in the IgG4 subclass in six patients. The percentage recovery of activity in the sum of the separated fractions generally corresponded to the activity in whole immunoglobulin, being 117 +/- 66% in the nine patients in whom this could be assessed, although in one of these, the activities in the sum of the fractions was much higher (284%). CONCLUSIONS: Unlike thyroid stimulating antibodies, thyroid stimulation blocking antibodies are not subclass restricted and are therefore likely to have a polyclonal origin. The IgG subclass distribution of these blocking antibodies resembles that of thyroglobulin and thyroid peroxidase antibodies.

Evaluation of serum basal thyrotrophin levels and thyrotrophin receptor antibody activities as prognostic markers for discontinuation of antithyroid drug treatment in patients with Graves' disease.

OBJECTIVE: We evaluated whether antithyroid drug treatment could be terminated more appropriately when both the serum basal thyrotrophin (TSH) level and TSH receptor antibody activity have become normal. DESIGN: This was a prospective randomized study of patients with Graves' disease followed for a mean of 28 months after the withdrawal of antithyroid drug treatment. PATIENTS AND INTERVENTIONS: A total of 174 patients with hyperthyroid Graves' disease were entered consecutively into this study, 11 of whom were subsequently excluded. One hundred and sixty-three patients were divided randomly into two groups having different criteria for the discontinuation of the antithyroid drug. Group 1 consisted of 79 patients whose antithyroid drug treatment was discontinued if both their serum TSH level and thyrotrophin binding inhibitor immunoglobulin (TBII) activity normalized. Group 2 consisted of 84 patients who were treated for 24 months irrespective of their serum TSH level and TBII activity. All patients were treated initially with 400 mg/day of propylthiouracil followed by decreasing doses that maintained a euthyroid state. MEASUREMENTS: Serum basal TSH levels and TBII activities were measured using a radioimmunometric assay and a radioreceptor assay, respectively, every 2 months during the antithyroid drug treatment. RESULTS: The remission rate of Group 1 (51.9%) was not significantly different from that (63.1%) of Group 2. The mean duration of treatment in Group 1 was 10.2 +/- 4.5 months (range 5-24, median 10). Median duration of treatment in Group 1 was 14 months shorter than in Group 2. In Group 1, the relapse rate was independent of the duration of the treatment. Further, the mean duration of treatment in the relapsed patients was not significantly different from that for patients who went into remission (9.9 +/- 3.8 vs 10.7 +/- 5.7 months; P greater than 0.1). In Group 2, the relapse rate was dependent on the time when both the serum TSH level and TBII activity were normalized (chi 2 = 27.0, d.f. = 4; P less than 0.001). When both the serum TSH level and TBII activity were normalized, the relapse rate of Group 2 was not significantly different from that of Group I for treatment periods of 6-12 months (25 vs 24.2%, P greater than 0.1), 12-18 months (33.3 vs 40%, P greater than 0.1), and 18-24 months (46.2 vs 50%, P greater than 0.1). However, the relapse rate of Group 2 was significantly lower than that of Group 1 when there was only a 6-month treatment period (5.6 vs 42.9%, P less than 0.05). Of the clinical and laboratory parameters measured, male sex, change of goitre size during treatment, and TSH levels and TBII values at the end of treatment, were of prognostic significance in predicting a relapse. CONCLUSION: The present study suggests that antithyroid drugs treatment can be terminated more appropriately when both the serum TSH level and TBII activity are made normal, thus avoiding prolonged and unnecessary drug treatment.