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Biomedical subjects

H Hatabu

Publications and source records attributed to H Hatabu.

At least 91 records · Page 5Linked to original sources
PubMed1989

Stimulation of cyclic AMP production in FRTL-5 thyroid cells by crude immunoglobulin fractions of serum from pregnant women.

In an assay for thyroid-stimulating antibodies, in which FRTL-5 thyroid cells were incubated with crude immunoglobulin (Ig) fractions precipitated from serum with 15% polyethylene glycol, significant increase in cAMP production was elicited by the samples from 25 (35.7%) out of 70 pregnant women. The highest value was 529.5%. There was a close correlation between thyroid stimulating activities and serum hCG concentrations (r = 0.708, P less than 0.001). When 125I-hCG was added to serum from pregnant women, about 20% of the radioactivity was incorporated into the Ig fractions. hCG preparations within a range of concentrations of 30-300 IU/m elicited 2.3-16.5 times increase in cAMP in a dose-dependent manner. Nine pregnant women with serum TSH concentrations less than the lower limit of the normal range (less than 0.25 mU/l) displayed significantly higher values for both thyroid stimulating activities and serum hCG concentrations (P less than 0.001, respectively) compared with those who had normal TSH levels in serum. These data suggest that hCG or its variant may stimulate the thyroid sufficiently to suppress secretion of TSH from the pituitary in some pregnant women.

Adult↗
PubMed1989

Pulmonary vasculature: high-resolution MR imaging. Work in progress.

High-resolution magnetic resonance (MR) imaging of the lung has the potential to depict not only small pulmonary vascular structures but also pulmonary blood flow. Five healthy volunteers were examined to assess the effects of (a) the use of two 5-inch surface coils located on the anterior and posterior chest walls, with a 24-cm field of view and a matrix of 256 X 256; (b) spin-echo acquisition with electrocardiographic (ECG) gating during systole or diastole; and (c) gradient recalled acquisition in a steady state (GRASS) with breath holding. These techniques yielded images showing small peripheral pulmonary vascular structures. Most subsegmental vessels and sixth- and seventh-order branches could be traced, especially near the coils. GRASS images obtained with dual surface coils and breath holding depicted fifth- and sixth-order branches. Preliminary results indicated that small pulmonary vessels can be imaged with MR with a combination of high-resolution techniques and ECG gating in diastole. The sensitivity and reproducibility of these techniques in demonstrating pulmonary vasculature warrant further investigation.

Adult↗
PubMed1989

Role of thyrotropin receptor antibodies in the development of hyperthyroidism: follow-up studies on nine patients with Graves' disease.

TSH binding inhibitor immunoglobulin (TBII) and thyroid-stimulating antibody (TSAb) activities were measured serially for 4-32 months in nine patients before and during development of hyperthyroidism due to Graves' disease. Initially, all were euthyroid, seven had thyroid enlargement, one had proptosis, and seven had high serum titers of antithyroid microsomal antibodies. The occurrence of hyperthyroidism was preceded by detection of both TBII and TSAb in four patients and detection of TSAb alone in four patients. One patient had neither TBII nor TSAb when euthyroid. The mean initial TBII and TSAb activities were 10.2 +/- 15.2% (+/- SD) and 2677 +/- 4620%, respectively, when these patients were euthyroid. When they became hyperthyroid, both TBII and TSAb activities increased in all patients. At that time, TBII was detected in all but one (eight of nine subjects; 88.9%), with a mean activity of 58.8 +/- 23.4% (+/- SD), and TSAb was detected in all nine patients, with a mean value of 4508 +/- 4429%. These findings not only indicate the crucial role of TSH receptor antibodies in the development of hyperthyroidism due to Graves' disease, but also suggest that a certain period of subclinical Graves' disease exists before the onset of overt hyperthyroidism in most patients, in the sense that they have TSH receptor antibodies, especially TSAb, in their serum even though they are euthyroid.

Adult↗
PubMed1989

Mechanisms of increased sensitivity for detection of thyroid stimulating antibodies by use of hypotonic medium.

We have attempted to clarify the mechanism whereby the sensitivity to detect thyroid stimulating antibodies by use of cultured thyroid cells is enhanced when sodium chloride is removed from isotonic medium. Preexposure of cultured porcine thyroid cells to 10(-4) mol/l cycloheximide increased the subsequent cAMP response to TSab stimulation in isotonic NaCl medium, but not in hypotonic NaCl-free medium. Crude membrane fractions from porcine thyroid tissues were incubated with 6 Graves' IgGs in NaCl or NaCl-free medium at 37 degrees C for 1 h, centrifuged, washed, added [125I]TSH, and incubated for another hour. The result of the 'residual TBII assay' indicated that all 6 IgGs exhibited greater inhibition of [125I]TSH binding to the membranes when pre-incubated under hypotonic than isotonic conditions. When cultured porcine thyroid cells were incubated with 7 TSab samples in NaCl or NaCl-free medium depleted with 3-isobutyl-1-methylxanthine at 37 degrees C for 1 h, washed, added the NaCl-free medium containing 3-isobutyl-1-methylxanthine, and incubated for another 2 h, the use of NaCl-free medium during the pre-incubation resulted in greater increase in cAMP elicited by all 7 samples. In summary, 1) an inhibitory mechanism upon adenylate cyclase seems to be involved under isotonic conditions and may require new protein synthesis; 2) the binding of TSH receptor antibodies to the TSH receptor increases when NaCl is removed from isotonic medium, and 3) these factors are considered responsible for the enhanced sensitivity under hypotonic conditions.

Animals↗
PubMed1988

Studies on thyrotrophin receptor antibodies in patients with euthyroid Graves' disease.

Thyroid stimulating antibodies (TSAb) and TSH-binding inhibitor immunoglobulins (TBII) were assessed in 30 patients with euthyroid Graves' disease. TSAb were detected in 24 cases (80.0%), the incidence being not significantly different from that in hyperthyroid Graves' disease (29/30, 97.6%). On the other hand, the incidence of TBII in patients with euthyroid Graves' disease (12/30, 40.0%) was significantly lower than that in patients with hyperthyroid Graves' disease (30/30, 100.0%). The mean TSAb and TBII activities in the euthyroid patients were significantly lower than in the hyperthyroid patients (P less than 0.005 and P less than 0.001, respectively). Both TBII and, more closely, TSAb activities correlated with T3-nonsuppressibility and inhibition of serum TSH response to TRH stimulation. The findings supported the stimulation in vivo of the thyroid by these antibodies. Both antithyroglobulin and antimicrosomal antibody titres in euthyroid Graves' disease were significantly lower than in hyperthyroid Graves' disease (P less than 0.05, P less than 0.01, respectively). Goitre size was significantly smaller (P less than 0.001), and 99mTc thyroid uptake was significantly lower (P less than 0.001) in the euthyroid than in the hyperthyroid group. Thus, the reduced mass of thyroid tissues responding to the stimulators was considered to be one of the factors responsible for the euthyroidism despite the presence of TSAb. The high incidence of TSAb and relatively low incidence of TBII in euthyroid Graves' disease indicate that the presence of TSAb does not necessarily lead to hyperthyroidism and that the development of overt thyrotoxicosis may require augmentation of both TSAb and TBII.

Adolescent↗
PubMed1988

Inhibition of thyrotropin-stimulated iodide uptake in FRTL-5 thyroid cells by crude immunoglobulin fractions from patients with goitrous and atrophic autoimmune thyroiditis.

We studied the effects of crude immunoglobulin (Ig) fractions of serum from patients with goitrous and atrophic autoimmune thyroiditis on TSH-, thyroid-stimulating immunoglobulin (TSI)-, forskolin-, and dibutyryl cAMP-stimulated 125I uptake by FRTL-5 thyroid cells. TSH-stimulated 125I uptake was inhibited by the Ig fractions from 15 patients with atrophic thyroiditis who had serum TSH binding inhibitor Igs (TBII), 10 (62.5%) of 16 TBII-negative patients with atrophic thyroiditis, 7 (43.8%) of 16 hypothyroid patients with goitrous thyroiditis who had no TBII activity, and only 2 (15.4%) of 13 euthyroid patients with goitrous thyroiditis who were negative for TBII. The mean inhibition of TSH-stimulated 125I uptake produced by the crude Igs from the former 3 groups of hypothyroid patients was statistically significant (P less than 0.001, P less than 0.001, and P less than 0.01, respectively) and correlated closely with the ability of the Ig fractions to inhibit TSI-stimulated 125I uptake (r = 0.882) and TSH-stimulated cAMP accumulation (r = 0.929). The inhibition of TSH- or TSI-stimulated 125I uptake by Ig samples containing TBII correlated significantly with the TBII activities. On the other hand, in the presence of Igs from TBII-negative hypothyroid patients, the inhibition of TSH-stimulated 125I uptake correlated significantly with that of forskolin-stimulated 125I uptake (r = 0.685). Although 6 (12.8%) of 47 Ig samples from hypothyroid patients inhibited dibutyryl cAMP-stimulated 125I uptake, the activities were marginal. These findings suggest that at least 2 types of antibodies are involved in the inhibition of TSH- or TSI-stimulated 125I uptake: 1 being a competitive inhibitor of TSH binding to its receptors, and another exerting influence on a step subsequent to TSH or TSI binding, presumably through adenylate cyclase inhibition.

Bucladesine↗
PubMed1988

Evaluation of TSH-receptor antibodies as prognostic markers after cessation of antithyroid drug treatment in patients with Graves' disease.

Clinical usefulness of thyroid-stimulating antibodies (TSab) and TSH-binding inhibitor immunoglobulins (TBII) for predicting the prognosis in patients with Graves' disease after cessation of antithyroid drug treatment was evaluated, and compared with that of T3 suppression test and goitre size. Among 46 patients who had been euthyroid on a maintenance dose of antithyroid drugs for at least one year and had discontinued taking medicine, 16 relapsed within one year (group 1), 7 relapsed later than 1 year (group 2), and 23 patients remained in remission for more than 1 year (group 3). Incidence of TSab, TBII, T3 nonsuppressibility and large goitre (transverse diameter longer than means of the values for the 46 patients: greater than or equal to 4.36 cm in females; greater than or equal to 4.74 cm in males) determined at the time of discontinuation of treatment was 87.5% (14/16), 56.3% (9/16), 78.6% (11/14) and 81.3% (13/16) in group 1; 66.7% (4/6), 28.6% (2/7), 50.0% (3/6), and 57.1% (4/7) in group 2, and 56.5% (13/23), 24.1% (5/23), 35.7% (8/23), and 26.1% (6/23) in group 3, respectively. All relapsed patients showed remarkable increases in both TSab and TBII activities at the time of relapse. High incidence of TSab in patients remaining in remission suggests that a reduced functional reserve of the thyroid, probably owing to destructive changes and/or shrinkage of the gland, may cause impaired responses to TSab and is involved in the cause of remission. Development of blocking type of TBII was not considered to be a cause of remission. Remission was predictable in all patients with any two of the indices such as negative TSab, positive T3 suppressibility, and small goitre.

Adolescent↗
PubMed1988

Comparison of thyroid stimulating activities measured by cyclic AMP production, those by radioiodine uptake in FRTL-5 cells and TSH-binding inhibitory activities in patients with hyperthyroid and euthyroid Graves' diseases.

By using an assay measuring cAMP production in FRTL-5 thyroid cells, thyroid stimulating antibodies (TSab) were detected in all of 15 patients with euthyroid Graves' disease (EG) and of 26 patients with hyperthyroid Graves' disease (HG). There was no significant difference between TSab activities in EG and in HG. In an effort to elucidate why EG patients remain euthyroid in spite of having TSab, we investigated the effect of the patient's crude immunoglobulin fractions on 125I uptake in FRTL-5 thyroid cells, one of the indices of stimulation subsequent to cAMP production. The 125I uptake stimulating (IUS) activity was positive in 46.7% (7/15) of EG patients and 88.5% (23/26) of HG patients, being significantly lower in the former than in the latter (P less than 0.02). Although the IUS activities significantly correlated with TSab activities in 41 patients with EG and HG (r = 0.784, P less than 0.001), the ratio of IUS to TSab in EG tended to be lower than that in HG. TSH-binding inhibitor immunoglobulins (TBII) activities in EG patients were negative or weakly positive, being significantly lower than those in HG patients (P less than 0.001). Thus, the ratios of TBII to both TSab and IUS activities were significantly higher in HG than in EG (P less than 0.01, P less than 0.001, respectively). The in vitro IUS activities also correlated with TBII activities (r = 0.441, P less than 0.001) and in vivo 99mTc thyroid uptake (r = 0.401, P less than 0.001) in both EG and HG patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Sensitive, practical bioassay of thyrotropin, with use of FRTL-5 thyroid cells and magnetizable solid-phase-bound antibodies.

We have developed a new method for assessing the bioactivity of thyrotropin (TSH) in human serum by measuring cAMP production in FRTL-5 thyroid cells as an index of stimulation. To eliminate serum inhibitors of the cAMP response to TSH, we purified samples by mixing them with anti-TSH antibodies coupled to magnetizable particles. This method of immunoaffinity purification was simple and suitable for the measurement of a large number of samples. The detection limit of the bioassay was 3.13 milli-int. units of human TSH per liter. Intra-assay and interassay coefficients of variation ranged from 5.4 to 8.6% and from 12.6 to 21.5%, respectively. The concentrations of bioassayable TSH closely correlated with those of immunoassayable TSH, both in the immunoaffinity-purified samples (r = 0.946, P less than 0.001) and in the serum samples (r = 0.945, P less than 0.001) from 14 euthyroid subjects and 53 hypothyroid patients with Hashimoto's thyroiditis. The bioactivity-to-immunoactivity ratio was almost constant (0.84 +/- 0.30; mean +/- SD) over the range of concentrations of immunoassayable TSH in serum, 6.3 to 177 milli-int. units/L. We also demonstrate that the technique is applicable to measurements of bioactivities of circulating forms of immunoreactive TSH in different pathophysiological conditions.

Animals↗
PubMed1987

[Radiation therapy of metastatic sites in hepatoma].

Ten patients with hepatoma who had received radiotherapy for their metastatic sites have been reviewed. In 13 lesions of bone metastasis in 7 patients complete pain relief from 5 lesions (38%) was achieved, while partial relief (54%) was obtained in other lesions. Of 3 patients with a brain metastasis, one attained complete symptomatic improvement with a 65% tumor reduction, and one of the remaining two gained a symptomatic palliation. In a patient with two pulmonary metastases, intraarterial chemotherapy showed a more remarkable effect when treatment was combined with radiotherapy than intraarterial chemotherapy alone. It may be concluded that radiation therapy is effected modality for palliating metastatic lesions of hepatoma.

Aged↗