Morphological and functional changes in neonatally X-irradiated thyroid gland in rats.

Exposure to ionized radiation in childhood has been recognized as a risk factor for the development of thyroid cancer and possibly for other thyroid disorders. However, the effects of neonatal radiation exposure on thyroid morphology and functions have never been explored despite its potential importance. One-week-old male Wistar rats were subjected to cervical X-irradiation at 6 and 12 Gy. Animals were examined at the ages of 2, 8 and 18 weeks old. For comparison, 8-week-old rats were cervically X-irradiated at the same doses. Thyroid histology was examined by computer-assisted microscopy to measure areas of colloid and epithelium of thyroid follicles as well as epithelial heights. In rats that received cervical X-irradiation at 1 week old, the colloid size of thyroid follicles decreased at the age of 8 weeks old in a radiation-dose dependent manner. This morphological change was persistently found at 18 weeks old. There were no significant differences in serum total T3 or T4 levels among the groups. Serum TSH levels increased significantly in 8-week-old rats neonatally X-irradiated. Thyroglobulin (Tg) mRNA and protein expressions were significantly decreased in the neonatally-irradiated group while thyroid peroxidase mRNA express increased at 18 weeks old. None of these changes were observed in the rats X-irradiated at 8 weeks old. In conclusion, our results clearly demonstrated that neonatal rat thyroid was sensitive to ionized radiation, developing specific morphological changes characterized by smaller thyroid follicles along with changes in serum TSH levels and Tg expressions in the thyroid tissue.

Electron capture dissociation of divalent metal-adducted sulfated N-glycans released from bovine thyroid stimulating hormone.

Sulfated N-glycans released from bovine thyroid stimulating hormone (bTSH) were ionized with the divalent metal cations Ca(2+), Mg(2+), and Co by electrospray ionization (ESI). These metal-adducted species were subjected to infrared multiphoton dissociation (IRMPD) and electron capture dissociation (ECD) and the corresponding fragmentation patterns were compared. IRMPD generated extensive glycosidic and cross-ring cleavages, but most product ions suffered from sulfonate loss. Internal fragments were also observed, which complicated the spectra. ECD provided complementary structural information compared with IRMPD, and all observed product ions retained the sulfonate group, allowing sulfonate localization. To our knowledge, this work represents the first application of ECD towards metal-adducted sulfated N-glycans released from a glycoprotein. Due to the ability of IRMPD and ECD to provide complementary structural information, the combination of the two strategies is a promising and valuable tool for glycan structural characterization. The influence of different metal ions was also examined. Calcium adducts appeared to be the most promising species because of high sensitivity and ability to provide extensive structural information.

Hypothyroidism among former workers of a nuclear weapons facility.

BACKGROUND: Ionizing radiation alters thyroid function, and workers at a nuclear weapons facility may be exposed to above environmental levels of radiation. METHODS: Hypothyroid status was determined for 622 former workers of a nuclear weapons facility located in Texas, using a combination of measured thyroid stimulating hormone (TSH) levels and thyroid medication history, as part of an on-going health surveillance program. We classified 916 unique job titles into 35 job categories. RESULTS: According to the most stringent TSH definition used in this study (0.3-3.0 IU/ml), 174 (28.0%) former workers were considered to be hypothyroid; of these 66 (41.8%) were females and 108 (23.3%) were males. In logistic regression analysis adjusted for age, gender, and smoking status, only having worked as a material handler (n = 18) exhibited an elevated risk of developing hypothyroidism compared to other jobs (OR 3.88, 95% CI 1.43-11.07). This is one of the jobs with suspected exposure to radiation. No excess risk of hypothyroidism was observed for any of the other job categories. CONCLUSIONS: There is suggestive evidence that only material handlers at this nuclear weapons facility may have elevated risk of hypothyroidism; further evaluation of thyroid health in this population is warranted.

Radioactive iodine therapy in Graves' hyperthyroidism: a prospective study from a tertiary referral centre in north India.

BACKGROUND: Radioactive iodine has gained widespread acceptance as the first-line therapy for Graves' hyperthyroidism and is the preferred treatment option in most situations. OBJECTIVE: A prospective study was conducted to look at the therapeutic practice of use of radioactive iodine in the treatment of Graves' hyperthyroidism, to determine whether the expected or desired therapeutic outcome is achieved. SETTINGS: A tertiary referral centre in north India, Delhi that caters to patients with thyroid disorders. METHODS: One hundred and seventy four consecutive subjects with Graves' hyperthyroidism, who were given radioactive iodine were followed up. RESULTS: There were 59 (33.9%) males and 115 (66.1%) females. The mean age was 41.8 +/- 9 years. The dose of radioactive iodine ranged from 2 mCi to 15 mCi and the mean dose administered was 5.2 +/- 1.9 mCi. After one year following radioactive iodine therapy, 29 (16.7%) subjects were euthyroid, 51 (29.3%) were hypothyroid and the remaining 94 (54%) had persisting hyperthyroidism. Those subjects with persisting hyperthyroidism at one year after radioactive iodine had received a significantly lower dose compared to the groups who had achieved cure (either euthyroidism or hypothyroidism). CONCLUSION: The study shows that the current practice of empirical low dose radioactive iodine therapy to avoid hypothyroidism results in majority of patients having persisting hyperthyroidism. There is a need to take a new look at the current practice to increase the cure rate.

Effects of 900 MHz electromagnetic field on TSH and thyroid hormones in rats.

In this study, the effects of exposure to a 900 megahertz (MHz) electromagnetic field (EMF) on serum thyroid stimulating hormone (TSH) and triiodothronine-thyroxin (T3-T4) hormones levels of adult male Sprague-Dawley rats were studied. Thirty rats were used in three independent groups, 10 of which were control (without stress and EMF), 10 of which were exposed to 900 MHz EMF and 10 of which were sham-exposed. The exposures were performed 30 min/day, for 5 days/week for 4 weeks to 900 MHz EMF. Sham-exposed animals were kept under the same environmental conditions as the study groups except with no EMF exposure. The concentration of TSH and T3-T4 hormones in the rat serum was measured by using an immunoradiometric assay (IRMA) method for TSH and a radio-immunoassay (RIA) method for T3 and T4 hormones. TSH values and T3-T4 at the 900 MHz EMF group were significantly lower than the sham-exposed group (p<0.01). There were no statistically significant differences in serum TSH values and T3-T4 hormone concentrations between the control and the sham-exposed group (p>0.05). These results indicate that 900 MHz EMF emitted by cellular telephones decrease serum TSH and T3-T4 levels.

[Contemporary role of scintigraphy in diagnosis, and evaluation of radioiodine therapy for treatment of thyroid diseases]. / Wspólczesna rola badan scyntygraficznych w diagnostyce i ocenie skutecznosci radioizotopowego leczenia chorób tarczycy.

The paper presents a short historical outline and contemporary use of scintigraphic studies of thyroid gland. Appropriate recommendations and correct interpretations of the results of routine thyroid scans and the usefulness of other scintigraphic studies with 111In-octreoscan, 99mTc-MIBI, 99mTc-DMSA, 18FDG and radiolabeled monoclonal anti-carcinoembryonic antigen antibodies were discussed in the light of the present thyroid diagnostic studies. Particular attention was paid to the dependence of the scintigraphic thyroid images upon the thyroid-stimulating hormone (TSH) level in the patient's serum. The chosen examples of scintigraphic studies show the advantages of scintigraphic evaluation of efficacy of radioiodine therapy. The most often mistakes of the scintigraphy interpretations were showed.

[The early and late reactions of the thyroid-gonadal link in rats of different age groups to the action of ionizing radiation]. / Rannie i otdalennye reaktsii tireoid-gonadnogo zvena krys raznykh vozrastnykh grupp na vozdeistvie ioniziruiushchego izlucheniia.

Pubertal and prepubertal rats were exposed to single (at doses of 0.1, 1, 10 Gy) or fractionated (at total doses of 1 and 10 Gy) X-ray irradiation. It has been shown that the irradiation is accompanied by the one-way phasic changes of thyroid and genital glands independently of the animals' puberty. Remote oppression of activity of the studied glands is the distinctive feature of these changes.

[The structural-functional status of the thyroid in patients with nodular goiter evacuated from the 30-kilometer zone of the Chernobyl Atomic Electric Power Station]. / Strukturno-funktsional'nyi stan shchytovydnoï zalozy khvorykh na vuzlovyi zob, evakuiovanykh iz 30-kilometrovoï zony ChAES.

An analysis was performed of results of ultrasonic and hormonal investigations in 239 patients with nodular goiter revealed in a screening-type clinical and laboratory examination of the 3371 persons evacuated from the 30-km zone of ChNPP, at their ages randing between 18 to 68 years. In 84.20% of patients in the group who took part in the elimination of effects of the Chernobyl accident (PEEA)--"PEEA + the evacuated"--the diameter of the nodules did not exceed 1 cm, in 6.1% it ranged from 1 to 2 cm, and in 13.41% it exceeded 2 cm. Distribution of nodules in the group "the evacuated" did not differ much from that in the above group. In 20% of patients with nodular goiter, there were functional disturbances concurrent with the autoimmune processes. No effects were detected of small doses of extra irradiation on the pattern of structural-and-functional indices in patients with nodular goiter evacuated from the 30-km zone of ChNPP who took part in EEA.

[Hypophyseal-thyroid system function in patients with nonspecific lung diseases who participated in the cleanup of the aftermath of the accident at the Chernobyl Atomic Electric Power Station]. / Sostoianie gipofizarno-tireoidnoi sistemy u bol'nykh nespsetsificheskimi zabolevaniiami legkikh, uchastvovavshikh v likvidatsii posledstvii avarii na ChAES.

A comparative evaluation was done of the condition of the hypophyseal-thyroid axis in those patients with unspecific pulmonary diseases having taken part in the elimination of the aftermath of the ChNPP accident in 1986-1988, as well as patients with no particular prior history and essentially healthy subjects. With the thyroxin content tending downwards, the main differences manifested themselves at the level of hypophyseal control. Provision of the organism with more active forms of hormones was found to be maintained in all the cases at the physiological level.

[Growth of children treated for leukemia or malignant lymphoma. Influence of cranial radiotherapy]. / Croissance des enfants traités pour leucémie ou lymphome malin. Influence de la radiothérapie crânienne.

We studied the height growth of 96 children presenting with acute leukemia or non Hodgkin lymphoma, together with an investigation of GH and TSH in 41 of them. There were 2 groups: group I consisting of 19 patients without brain irradiation and group II consisting of 77 patients with prophylactic brain irradiation. Initial average height was identical in both groups. Growth rate was significantly decreased in group II but not in group I (p less than 0.01). There is a correlation between the decrease of growth rate and the decrease of GH to arginine stimulation test (p less than 0.03). A lack of response to GRF-44 was noted in 4 of 11 investigated patients. TSH and prolactin secretions were unchanged.

Effect of gamma irradiation on biological activity of thyrotropin.

The biological activity of thyrotropin (TSH) was tested after sterilization by 0.5 and 12.5 Mrad of gamma irradiation. It was found that the biological activity (McKenzie's assay) of TSH irradiated in dry state was not affected during the first month after sterilization by doses of 0.5 and 2.5 Mrad. However, substantial decrease of TSH biological activity was observed 3--5 months after the irradiation, the lower activity being after the former dose. The irradiation of TSH by 12.5 Mrad in dry state and by 0.5 and 2.5 Mrad in solution resulted in a decrease of biological activity already during first month. The structural changes in the molecule of TSH were apparently not very extensive, since a decrease of disulfide bonds from 0.96 to 0.77 M per 1M of TSH was found immediately after the irradiation, while UV absorbancy and electrophoretic mobility on polyacrylamide gel electrophoresis were unaffected. These changes were followed by the decrease of TSH stability during storage in dry state. It is hypothesized that TSH molecule may be affected in beta subunit or in its connection with alpha.