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Background: Levothyroxine has often been given to patients operated on for nodular goiter to prevent recurrence. The rationale is that suppression of thyroid-stimulating hormone (TSH), considered to be the main growth factor in this disease, can be obtained by administration of levothyroxine., Methods: Sixty patients undergoing operation for nontoxic nodular goiter were randomized in two groups: (1) thirty-two were administered levothyroxine at substitutive dosage (100 micrograms) or placebo and (2) twenty-eight were given levothyroxine at suppressive dosage (2.2 to 3 micrograms/kg/day). Levels of thyroid hormones and TSH were evaluated every 6 months. Recurrences detected by echography were then considered., Results: After a 3-year follow-up we observed 25 of 32 recurrences in group 1 and 6 of 28 in group 2 (p < 0.005). Subjects with endemic goiter problems responded better to therapy. Patients with a multinodular goiter responded better than patients with a uninodular goiter. No difference was found regarding the type of surgical treatment (subtotal thyroidectomy vs lobectomy)., Conclusions: The results confirmed suppressive therapy as actually being effective in preventing recurrences at least in iodine-deficient regions like Italy. Thus for these patients it may be suggested as a prophylactic treatment after operation.

The effects of lithium carbonate on thyroid was evaluated in 40 consecutive psychiatric patients on long-term treatment with this drug. Five patients had clinical and/or biochemical hypothyroidism. Twenty four (60%) subjects showed goiter of different size, including very large glands. A very high prevalence of goiter (87%) was observed in the 15 patients coming from a moderate endemic area. A lower incidence of goiter (44%) was found in subjects coming from non endemic areas. Goiter was associated with significantly elevated serum thyroglobulin concentration similar to that reported in endemic or sporadic nontoxic goiter. None of 25 psychiatric patients not receiving lithium therapy was hypothyroid and only three (12.5%) of them showed a small size goiter. These data indicate a very high prevalence of thyroid enlargement in patients on lithium therapy and suggest the opportunity to institute a prophylactic thyroid hormone treatment at least in subjects coming from endemic areas.

The ability of detergents (Triton X-100 and deoxycholate), high ionic strength solution (3 M KC1), and proteolytic enzymes (papain and trypsin) to solubilize human thyroid microsomal antigen was studied. Antigenic activity released from thyroid microsomal preparation into the incubation mixture was separated by centrifugation at 143,000 x g for 90 min and measured using 125I-labeled human immunoglobulin G (IgG) with elevated antimicrosomal (anti-M) and undetectable anti-thyroglobulin antibodies (anti-M IgG). All solubilized materials were shown to bind [125I]anti-M IgG and to inhibit its binding to untreated thyroid microsomes. These effects were specific and dose related. Measurements of specific activity and total amount of solubilized antigen by an absorption technique showed that Triton X-100 was the most effective agent, followed by deoxycholate, papain, trypsin, and 3 M KC1 in decreasing order. Affinity chromatography with the deoxycholate-solubilized material coupled to Sepharose 4B resulted in a 15.6-fold purification of [125I]anti-M antibodies. The present results indicate that thyroid microsomal antigen may be solubilized by several agents and this can provide the basis for its identification and purification.