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Background: Evaluation of the influence of hormonal and reproductive factors and the role of cigarette smoking in the onset of thyroid carcinoma., Methods: Comparison between a group of 78 female patients all living in the district of Lazio, operated for thyroid follicular or papillary carcinoma at the Third Clinical Surgery Dept., Policlinico Umberto I, Rome (Italy) from 1990 to 1997, and a group of 150 women free from neoplastic and/or hormonal pathology, recruited by the compilation of a questionnaire., Results: Cigarette smoking can be associated with risk reduction of developing thyroid neoplasia. On the contrary, no risk variation has been associated with the number of normal pregnancies, with pregnancy interruption both spontaneous and voluntary and with anthropometric characteristics of the analysed individuals. The first pregnancy at very young age and the use of contraceptives seem to determine a risk increase of thyroid cancer, at the limit of statistical significance., Conclusions: The antiestrogenic action of cigarette smoking exerts a protective action for thyroid carcinomas. Spontaneous or volontary interruption of pregnancy did not show a significant effect as risk factor.

Thyroglobulins (Tgs) have been obtained from macro-microfollicular goiter, toxic adenomas, papillary carcinomas and metastatic lympho-node and chromatographed by gel filtration. The 19S Tgs so obtained have been characterized by isoelectric focusing (IEF) and immunoblotting. IEF showed microheterogeneity pattern of Tgs from normal tissue, macro-microfollicular goiter and toxic adenomas to be within pH range from 4.2 to 4.5, while that from papillary carcinomas and metastatic lympho-node showed a wider microheterogeneity. Passive blotting of focused Tgs and immunoreaction with rabbit anti-Tg peroxidase conjugated antibody have been carried out and a positive reaction for all examined samples have been evidenced. Also two bands, focused at more cathodic pH value (pH 4.7), observed in IEF patterns of Tgs from carcinomas and metastatic lympho-node, gave a positive reaction with anti-Tg conjugated antibody. These differences observed in IEF and immunoblotting patterns of Tgs from papillary carcinomas and metastatic lympho-node are discussed in this report.

Following the introduction of echography it has became evident that a large proportion of nodules (15-37%) in euthyroid nodular goiter is entirely or partially cystic (20% in the A. experience). It is thought that cystic areas are subsequent to hemorrhagic necrosis occurring during goitrogenesis and therefore the term "pseudocysts" seems to be preferred. The article summarizes some hypothetical mechanisms of pseudocyst formation. In pseudocysts of recent onset a direct or indirect viral or bacterial etiology is suggested; in longstanding pseudocysts a deficient angiogenesis or immunotoxic mechanisms are proposed.

Prevalence of euthyroid nodular goiter varies widely according to the endemia of the region studied. The goiter hyperplasia under goitrogenic stimuli progresses in the formation of nodules. Presently the pathophysiology of the thyroid nodules' formation in euthyroid nodular goiter is unknown. The A. reviews the two current hypothesis on the clonal origin of thyroid nodules. According to one hypothesis the nodule issues as the result of a coordinated replication of a cluster of follicles with an increased growth potential. According to the second hypothesis the formation of new follicles during goitrogenesis is due to a sprouting of one or a few cells from the follicles shell; nodules formation is the result of post-necrotic fibrosis and uneven growth.

A Sepharose-coupled 19S human thyroglobulin has been used as an immunoadsorbent to isolate anti-thyroglobulin autoantibodies and to evaluate the antigen-antibody interactions. With the system proposed a high yield of active antibody molecules was obtained. It is possible to evaluate both the soluble and precipitating 'immunological interactions', thus avoiding the use of the double antibody technique.

Prevalence rates of serum thyroid antibodies in a Somalian population have been compared with those of an Italian population. Thyroid antibodies have been evaluated by passive haemagglutination (microsomal antigen) and by 125I-thyroglobulin binding. In the Italian survey 13% of all subjects were positive for thyroid antibodies. A significantly lower prevalence of thyroid antibody positive subjects was found in the Somalian group (2,07%, P less than 0.001). It is suggested that the observed difference between Somalian and Italian populations could reflect nutritional or genetic causes which influence the antithyroid autoimmune response.

Purified human thyroglobulin (Tg) was enzymatically digested with trypsin. After completion of digestion, the tryptic digest was fractionated by gel filtration on a Biogel A 1.5 m column. Further separation and isolation of the major peak C was carried out on a Sephadex G-75 column. Nine fractions were separated and antigenic properties evaluated by a specific and sensitive radioimmunoassay using a rabbit antiserum to 19S Tg and three different antisera from patients with autoimmune thyroid diseases. The Tg fragments react with both hetero- and auto-antisera. The highest antigenic activity was found on larger fragments, but a fairly good activity was also observed on fragments (C6, C7) with lower molecular weight. Antigenic determinants of Tg differ in individual sera suggesting that different sets of determinants elicit the autoimmune process.