Presence of endothelin-1 in the normal and pathological human thyroid.

An immunohistochemical study with two rabbit polyclonal antibodies I-AR76 and CA-08-351 against Endothelin-1 (ET-1) was performed in 133 human thyroid specimens: 5 normal thyroids, 30 multinodular goiters (15 toxic and 15 nontoxic), 20 Graves' diseases, 5 Hashimoto's thyroiditis, 26 adenomas (6 Hürthle cell, 16 toxic and 4 nontoxic), 30 classic papillary carcinomas, 3 minimally invasive follicular carcinomas, 1 widely invasive follicular carcinoma, 3 undifferentiated carcinomas and 10 medullary carcinoma. All normal thyroids, non toxic multinodular goiters and non toxic adenomas, 4 (66%) Hürthle cell adenomas, 3 (15%) Graves' diseases, 1 (33%) case of minimally invasive follicular carcinoma showed rare follicular cells with weak cytoplasmic immunoreactivity. Many immunoreactive follicular cells, with or without oxyphilic changes, were observed in all specimens of Hashimoto's disease, while the lymphocytic infiltrate was always negative. Twenty-seven (90%) classic papillary carcinomas were positive. Immunoreactivity was intracytoplasmic, weak in 14 cases and intense in 13. The cells of toxic adenoma and toxic multinodular goiter were negative, whereas the acellular stroma was intensely positive in both cases. Medullary and undifferentiated carcinomas were negative. These results show ET-1 immunoreactivity in normal and pathological human thyroids. In particular, the high content of this peptide in the thyroid papillary carcinoma suggests that ET-1, whose mitogenic role has recently been emphasized, could be involved in the growth of this tumor.

Cold thyroid nodules: a new application of percutaneous ethanol injection treatment.

Sonographically guided percutaneous ethanol injection (PEI) has been recently used with excellent results in the treatment of toxic and pretoxic thyroid adenoma. The aim of the present study was to assess the efficacy of PEI also in the treatment of "cold" thyroid nodules. Twenty patients, each with a single thyroid nodule, underwent PEI. In all cases the nodules were found to be cold by thyroid scintiscan. A total of 16.1 mL +/- 3.1 mL of ethanol was injected once a week. No adverse effects were observed during therapy. A striking nodular shrinkage was obtained in all cases, ranging from 72.8% to 97.6% (mean 84.5%, p < 0.001 vs pretreatment volume). These preliminary results suggest that PEI is an effective and safe therapy that may be useful in the treatment of thyroid nodules as an alternative to other therapies (surgery, L-thyroxine).

[Echo-guided percutaneous alcohol injections of cold non-neoplastic thyroid nodules. Preliminary experience]. / Alcolizzazione percutanea ecoguidata dei noduli tiroidei freddi non neoplastici. Esperienza preliminare.

Percutaneous ethanol injection (PEI) has been recently used with excellent results to treat toxic and pretoxic thyroid adenomas. We investigated PEI efficacy also in the treatment of "cold" thyroid nodules in 31 patients with nodular goiter. All nodules were proved to be cold on thyroid scintigraphy. There was no clinical or cytologic suspicion of cancer. Informed consent to the experimental study was always obtained. Each patient received 24 +/- 4.1 ml of ethanol, injected once or twice a week. No significant side-effects were observed during treatment. All nodules shrank 66-97.6% (mean: 85.5%, p < 0.001 vs pretreatment volume). US-guided cytologic sampling was repeated at 3 months' follow-up. PEI was precautionally repeated in 4 patients exhibiting sparse follicular cells. Further data about this group are not available yet. These preliminary results prove PEI to be an effective and safe technique to treat thyroid nodules and to make a valuable alternative to surgery and L-thyroxine.

Amiodarone iodine-induced hypothyroidism: risk factors and follow-up in 28 cases.

Amiodarone, an iodine-rich drug widely used for the treatment of cardiac tachyarrhythmias, may induce either hyperthyroidism or hypothyroidism. Of 467 patients chronically treated with this drug referred to our institution, amiodarone iodine-induced hypothyroidism (AIIH) developed in 28 patients (6%). AIIH patients were subdivided into two groups according to the presence (group A) or absence (group B) of underlying thyroid abnormalities. Thyroid autoantibodies were present in 10 of 19 patients from group A and 0 of 9 patients from group B. The thyroid 24-h radioiodine uptake (RAIU) was evaluated in 15 patients: low values (less than 4%) were found in three patients and detectable values (7-50%) were observed in 12. Perchlorate discharge tests were positive in all four patients tested. Follow-up data were available in 20 patients (16 in group A and four in group B). Hypothyroidism was transient in 12 (60%) and persistent for several months after amiodarone withdrawal in eight (40%). While all patients in group B had transient hypothyroidism, 50% of patients with underlying thyroid abnormalities (group A) had persistent hypothyroidism. Thyroid autoantibodies were found in seven of eight patients with persistent hypothyroidism and in only three of 12 patients with transient hypothyroidism. Conversely, seven of 10 patients with positive thyroid autoantibodies had persistent hypothyroidism and 9 of 10 patients with undetectable thyroid autoantibodies had transient hypothyroidism. These data indicate that: (i) AIIH may develop in patients with or without underlying thyroid abnormalities; (ii) RAIU is inappropriately elevated in many patients with AIIH; (iii) intrathyroidal iodine is not organified; (iv) serum thyroid autoantibodies represent a risk factor for the development of AIIH; (v) AIIH spontaneously remits after amiodarone withdrawal in patients without thyroid abnormalities, but may persist in patients with concomitant thyroid disorders, especially those with circulating thyroid autoantibodies.

Short term administration of potassium perchlorate restores euthyroidism in amiodarone iodine-induced hypothyroidism.

We studied the effect of potassium perchlorate (KClO4) in patients with hypothyroidism due to amiodarone. The short term administration of KClO4 to six such patients led to prompt restoration of euthyroidism, while the three untreated patients remained hypothyroid for 2-6 months. Since KClO4 inhibits thyroid iodide transport, thereby blocking further entrance of iodide into the thyroid and decreasing intrathyroidal iodide content, amiodarone-associated hypothyroidism is probably secondary to the inhibitory effect of excess intrathyroidal iodine on thyroid hormone synthesis.

Treatment of amiodarone associated thyrotoxicosis by simultaneous administration of potassium perchlorate and methimazole.

Amiodarone iodine induced thyrotoxicosis occurs frequently in patients residing in areas of mild iodine deficiency and in patients with preexisting goiter. Drug therapy of the hyperthyroidism is often unsuccessful. Twenty-three patients with amiodarone induced thyrotoxicosis were either not treated, treated with 40 mg methimazole daily or with methimazole and 1 gm potassium perchlorate daily for up to 40 days and then with methimazole alone. Thyrotoxicosis was more likely to spontaneously remit in patients without goiter. Therapy with methimazole alone was unsuccessful in inducing euthyroidism in 5 patients with goiter. However, combined therapy with methimazole and potassium perchlorate rapidly alleviated hyperthyroidism in almost all patients with goiter. This drug combination is successful because perchlorate inhibits the active transport of iodine into the thyroid and methimazole blocks the intrathyroidal synthesis of thyroid hormones.

Is humoral thyroid autoimmunity relevant in amiodarone iodine-induced thyrotoxicosis (AIIT)?

Amiodarone, an iodine containing drug, may induce thyrotoxicosis by an uncertain mechanism. In this study the role of thyroid autoimmunity was evaluated in 28 consecutive patients referred to us because they had become hyperthyroid during long-term amiodarone administration. Titres of thyroglobulin and thyroid microsomal antibodies, TSH binding-inhibitory and thyroid stimulating antibodies were evaluated. Underlying thyroid disorders were demonstrated in 20 patients (9 of them had toxic diffuse goitre, seven toxic multinodular goitre and four toxic adenoma), while eight patients did not show any apparent thyroid gland abnormality. Circulating thyroid autoantibodies could be found in all amiodarone iodine-induced hyperthyroid patients with toxic diffuse goitre and in one with toxic multinodular goitre, whilst they were absent in the other patients. These studies suggest that thyroid autoimmunity has little if any role in the development of thyrotoxicosis in amiodarone treated patients without underlying thyroid disorders. Furthermore, in amiodarone-iodine-induced thyrotoxicosis associated with various thyroid diseases, the humoral markers of thyroid autoimmunity show an incidence similar to that observed in spontaneous hyperthyroidism.

Environmental iodine intake and thyroid dysfunction during chronic amiodarone therapy.

Amiodarone, an iodine-containing drug used frequently in the treatment of cardiac arrhythmias and angina pectoris, has many effects on thyroid hormone metabolism, including decreasing the production of triiodothyronine (T3) and decreasing the clearance of thyroxine and reverse T3. These effects result in elevated serum thyroxine and reverse T3 concentrations and decreased serum T3 concentrations. In addition, iodine-induced hyperthyroidism or hypothyroidism may occur in patients chronically treated with amiodarone. This study is a retrospective analysis of the incidence of thyroid dysfunction in Lucca and Pisa, West Tuscany, Italy, and in Worcester, Massachusetts. Hyperthyroidism was a more frequent (9.6%) complication of amiodarone therapy in West Tuscany, where iodine intake is moderately low; hypothyroidism was more frequent (22%) in Worcester, where iodine intake is sufficient. In patients receiving chronic amiodarone therapy, clinically suspected hyperthyroidism is best confirmed by showing elevations in serum T3 or free T3 concentrations; hypothyroidism is best diagnosed by showing an elevated serum thyrotrophin concentration. Thyroid function should be carefully monitored in patients receiving amiodarone chronically, especially if they have goiter or Hashimoto's thyroiditis.