Kazuo Kaise

Thyroid peroxidase activity in euthyroid and mild hypothyroid patients with Hashimoto's thyroiditis

Thyroid peroxidase (TPO) activity was measured spectrophotometrically according to Hosoyas guaiacol method. The mean TPO activity in ten patients with Hashimotos thyroiditis was 19.8 +/- 7.6 (mean +/- SE) in an arbitrary unit, which was not significantly different from the normal value in seven normal thyroid tissues (33.7 +/- 5.4). The ten patients were divided into two groups, euthyroid and mild hypothyroid, on the basis of their basal serum TSH. In the euthyroid group, TPO activity (8.17 +/- 1.3) was significantly less than the normal tissue (p less than 0.01). In the hypothyroid group, TPO activity (27.64 +/- 13.8) was almost similar to the normal tissue. A positive correlation was obtained between TPO activity and serum TSH in ten patients with Hashimotos thyroiditis (r = 0.85, p less than 0.01). It was concluded that TPO activity is significantly decreased in Hashimotos thyroiditis even when the thyroid function was still within normal range, but the activity might be restored to normal in hypothyroid patients by the stimulation of elevated TSH.

The relationship between serum IAP and peripheral K cells in patients with subacute thyroiditis

In a previous study, we showed that the percentage of peripheral K cells of patients with subacute thyroiditis (SAT), determined by a plaque-forming cell technique, was significantly lower than that of normal controls, and that ther sera from SAT significantly inhibited the activity of K cells in normal lymphocytes, suggesting that in the sera of SAT there is some factor which inhibits K cell activity. In this study, we investigated the relationship between K cells and the serum immunosuppressive acidic protein (IAP), the sex difference in percentage of K cells, and the absolute count of K cells in patients with SAT. In normal controls, there was a sex difference in the percentage of K cells in total lymphocytes; the percentage was significantly lower in women (mean +/- S.D., 5.0 +/- 2.0%; n = 12; p less than 0.01) than in men (8.4 +/- 2.9%; n = 20). However, there was no sex difference in the absolute count of peripheral K cells. In the acute phase of SAT, the percentages of K cells wee 2.4 +/- 1.8%; 2.4 +/- 1.9% and 2.7 +/- 1.0% in 19 patients, 16 females and 3 males, respectively, which were significantly lower than 6.8 +/- 3.0%, 5.0 +/- 2.0% and 8.4 +/- 2.9% in 25 controls, 12 females and 13 males, respectively. The absolute counts of K cells in the acute phase of SAT were 56 +/- 45/mm3 and 58 +/- 48/mm3 in 13 patients including 11 females, respectively, which were significantly lower than 165 +/- 63/mm3 and 153 +/- 73/mm3 in 12 patients including 5 female controls, respectively. It was observed that serum IAP values in SAT were correlated negatively with the percentage of K cells and positively with the inhibition rate of SAT sera on K cells from normal subjects. Moreover, purified IAP showed a dose-related inhibition on the K cells from the control subjects. These results suggest that IAP in the sera of SAT seems to be one of the factors which inhibits the activity of K cells.

[Free thyroxine estimation for screening of hyper- and hypothyroidism in an adult population].

Serum free thyroxine (FT4) was determined in 1,114 adults (male 239, female 875) in a periodic health evaluation in 1980 to detect unsuspected thyroid dysfunction, especially hyper- and hypothyroidism. The participants were dwelling in two towns of Miyagi prefecture. Beside FT4, serum T4 and T3 were also determined by radioimmunoassay. If thyroid dysfunction was suspected, further detailed examinations such as TRH-test (500 micrograms i.v.), radioimmunologic determinations of serum TSH and TBG, resin-sponge T3-uptake, 24-hr thyroid radioiodine 131I-uptake, radioiodine thyroid scan and anti-thyroid antibodies were performed. There were 3 patients with hyperthyroidism (0.27%), 4 with hypothyroidism (0.36%), 3 taking thyroid medication (2; Hashimotos disease, 1; goiter), 3 on estrogen administration, 4 with Hashimotos disease and 1 with goiter. Excluding these 18 patients, FT4, T4 and T3 values in 1,096 euthyroid subjects, 236 males and 860 females, were 1.1 +/- 0.3 (mean +/- S.D.), 1.1 +/- 0.3 and 1.0 +/- 0.3 ng/100 ml, 8.9 +/- 1.5, 8.8 +/- 1.6 and 9.0 +/- 1.5 micrograms/100 ml, and 122 +/- 33, 125 +/- 26 and 122 +/- 35 ng/100 ml, respectively. Serum FT4, T4 and T3 showed the distribution of logarithmic normal probability. The 95% normal range for free T4 was 0.60 to 1.80 ng/100 ml, total T4 6.0 to 11.8 micrograms/100 ml, and T3 84 to 176 ng/100 ml, respectively. Out of 1,114 subjects examined, the cases to be reexamined for the higher serum concentration than normal were 26 in FT4, 35 in T4 and 27 in T3, respectively. And the cases for lower values were 28 in FT4, 31 in T4 and 24 in T3, respectively. Serum FT4 values in the subjects during the administration of estrogens were within the normal range. FT4 and T4 were low in four patients with hypothyroidism, but two of them showed normal T3 values. Determinations of serum FT4, total T4 and total T3 were all useful for the screening of hyperthyroidism. But serum FT4 was the most reliable of the three. Determination of either serum FT4 or total T4 was suitable for the screening of hypothyroidism, but serum total T3 measurement did not cover all patients with hypothyroidism.