Anti-gastric parietal cell antibodies for autoimmune gastritis screening in juvenile autoimmune thyroid disease

OBJECTIVE

Patients with autoimmune thyroid disease (ATD) have a higher prevalence of autoimmune gastritis (AIG) compared with the general population. The association between ATD and AIG is poorly characterized in the pediatric age. We reviewed the prevalence of anti-gastric parietal cell antibodies (PCA) in young patients with ATD to evaluate its usefulness as a marker for AIG screening.

METHODS

We evaluated 220 children and adolescents (11.28 ± 6.37 years) with ATD (186 with autoimmune thyroiditis (AT) and 34 with Graves' disease (GD). At ATD diagnosis and annually thereafter, blood counts and PCA levels were measured. In patients positive for PCA, plasma gastrin, chromogranin A, vitamin B₁₂, iron and ferritin levels and H. pylori antigen were measured. PCA-positive patients > 18 years were invited to undergo a gastroscopic exam.

RESULTS

PCA positivity was detected in ten (4.5%) subjects (5F/5M; 12.6 ± 3.4 years). The prevalence of PCA positivity was not significantly different in the comparison of GD and AT patients (p = 0.9). PCA positivity was detected after 2.7 ± 2.7 years of follow-up in AT and 4.4 ± 4.0 years in GD (p = 0.4). Autoantibody positivity was more prevalent in female patients, in both AT and GD (p = 0.02 and p = 0.03, respectively). At detection of PCA positivity, five out of ten PCA-positive patients had iron deficiency, four vitamin B₁₂ deficiency, two anemia, three hypergastrinemia and two elevated chromogranin values. Two patients had H. pylori infection. Gastroscopy was performed in the five ATD patients and in all patients, AIG was confirmed.

CONCLUSION

In the juvenile population, ATD and AIG may also be associated. PCA screening is useful to detect subjects at risk for this condition. Due to the longer life expectancy of the pediatric population and considering the relatively high risk of malignant transformation, early surveillance monitoring is mandatory for children and adolescents with ATD.

Tall cell and diffuse sclerosing variants of papillary thyroid cancer: outcome and predicting value of risk stratification methods

PURPOSE

Tall cell (TCV) and diffuse sclerosing (DSV) variants are aggressive variants of papillary thyroid cancer (PTC). We compared the risk of recurrent/persistent disease in patients with TCV, DSV and classical PTC (cPTC) and evaluated the prognostic accuracy of initial vs. ongoing risk stratification.

METHODS

A consecutive series of DSV (n = 54), TCV (n = 72) and cPTC (n = 184) patients was retrospectively analyzed. TCV and DSV patients were first risk stratified for recurrent/persistent disease without considering the histotype as a risk factor and subsequently, 6-24 months after initial treatment, re-classified on the basis of the response to therapy (ongoing risk stratification).

RESULTS

Extrathyroidal extension was more frequent in DSV than in TCV and cPTC patients (p < 0.05); moreover, only DSV tumors had a higher rate of recurrent/persistent disease when compared to cPTC treated with the same protocol (total thyroidectomy followed by ¹³¹I treatment) (p < 0.01). After initial treatment, 54.2% of TCV and 20.4% of DSV patients were classified at low risk, while at ongoing risk stratification, the excellent response (low risk) was higher for both TCV (77.8%) and DSV (50.0%) patients relative to initial stratification (both p < 0.01). Using ongoing risk classification, positive predictive value (PPV) for persistent/recurrent disease was higher relative to initial risk stratification for both TCV (PPV = 93.8 vs. 39.4%) and DSV (PPV = 63.0 vs. 34.9%), p < 0.05 for both.

CONCLUSIONS

In our series DSV, but not TCV patients, had poorer outcome than cPTC treated with the same protocol. Moreover, the ongoing risk stratification predicted outcome better than the initial classification in both TCV and DSV patients.

Comparison of conventional L-thyroxine withdrawal and moderate hypothyroidism in preparation for whole-body 131-I scan and thyroglobulin testing

PURPOSE

After thyroidectomy for thyroid cancer, patients often withdraw L-T4 for diagnostic or therapeutic purposes, showing signs and symptoms of hypothyroidism. A slighter hypothyroidism (reducing L-T4 to one-half) has been proposed to limit these inconveniences. We evaluated half-dose L-T4 protocol, in comparison to conventional L-T4 withdrawal, in terms of effectiveness and improvement of clinical and biochemical disorders.

METHODS

We randomized 55 thyroid cancer patients into two groups: 29 patients underwent 5 weeks of half-dose of previous L-T4 treatment (HD group); 26 patients replaced L-T4 with L-T3 for 3 weeks followed by 2 weeks of withdrawal (TW group). Clinical features (Zulewsky clinical score) and biochemical parameters (lipids, liver, and muscle enzymes) were evaluated in all patients at baseline and after 5 weeks.

RESULTS

Total cholesterol, creatine kinase, lactate dehydrogenase, aspartate aminotransferase, and alanine aminotransferase increased at 5 weeks in both groups, but significantly more in TW, but no difference was found by clinical score. Patients who achieved the thyroid-stimulating hormone (TSH) target value (25 µU/ml) were 92.3% in TW group and 48.3% in HD group (p < 0.001). In the HD group, only basal TSH statistically correlated with the achievement of the TSH target. Receiver operating characteristic curves indicated that a basal TSH ≥0.52 μU/ml is required to reach an adequate TSH level.

CONCLUSIONS

Half-dose L-T4 protocol, compared to conventional L-T4 withdrawal, is associated with less biochemical disorders but no significant clinical advantage. Therefore, the half-dose protocol reaches an adequate TSH target in 48.3% of patients and is not effective unless basal serum TSH is ≥0.52 μU/ml.

Pregnancy outcome in women treated with methimazole or propylthiouracil during pregnancy

PURPOSE

Control of thyroid function in hyperthyroid women during pregnancy is based on antithyroid drugs (ATD) [propylthiouracil (PTU) and methimazole (MMI)]. While a teratogenic effect has been suggested for MMI and, more recently, for PTU, a clear demonstration is still lacking. Aim of this study was to assess the safety of ATD during pregnancy.

METHODS

A total of 379 pregnancies were retrospectively recruited in eight Italian Departments of Endocrinology and divided in five groups: (1) MMI-treated and euthyroid throughout pregnancy (n = 89); (2) MMI-treated and hyperthyroid on at least two occasions (n = 35); (3) PTU-treated women and euthyroid throughout pregnancy (n = 32); (4) PTU-treated women and hyperthyroid on at least two occasions (n = 20); and (5) non-ATD-treated (n = 203). Data on maternal thyroid function, miscarriages, type of delivery, neonatal weight, length and TSH, perinatal complications and congenital malformation were analyzed.

RESULTS

The gestational age at delivery, the rate of vaginal delivery, neonatal weight, length and neonatal TSH did not significantly differ among groups. In all groups, the rates of spontaneous miscarriage and of major congenital malformations were not higher than in the general population. No newborns were born with a phenotype similar to those described in the "MMI embryopathy".

CONCLUSIONS

While a clear demonstration of a teratogenic effect of MMI is currently lacking, it seems reasonable to follow the current guidelines and advice for PTU treatment in hyperthyroid women during the first trimester of pregnancy. Further, large and prospective worldwide studies will be needed to fully clarify the issue of ATD safety during pregnancy.

The tall cell variant of papillary thyroid carcinoma: clinical and pathological features and outcomes

BACKGROUND

The tall cell variant (TCV) is a relatively rare variant of papillary thyroid cancer. Since a controversy exists whether or not the TCV has a worse outcome, the aim of our study was to retrospectively compare the clinicopathological features and outcomes in a group of TCV patients and a larger group of patients with classical papillary thyroid carcinoma (cPTC).

SUBJECTS AND METHODS

Data from 30 TCV and 293 cPTC patients were analyzed. Among the 293 cPTC, we also selected a "high-risk" cPTC group (no.=103) that was treated with the same protocol used for the TCV patients. All data were managed by Cox analysis.

RESULTS

Compared to all cPTC patients, TCV subjects displayed only a significantly higher rate of extrathyroid extension. At multivariate analysis, TCV was not an independent variable for the prediction of a high risk of persistent/recurrent disease. At the last follow-up observation, there was no difference in the disease status between the TCV and all cPTC patients. Moreover, "high-risk" cPTC patients had a significant increase in persistent/recurrent disease.

CONCLUSIONS

In our study, although the TCV histotype is associated with a higher prevalence of extrathyroid extension, it is characterized by an outcome that is not significantly different from that of all cPTC patients and is more favorable than that of "high-risk" cPTC patients. Only those TCV patients classified as "high risk" based on specific pathological and clinical features, according to current guidelines, should be treated aggressively, such as with a total thyroidectomy, neck lymph node dissection or ablative radioiodine treatment.

Effects of prophylaxis with iodised salt in an area of endemic goitre in north-eastern Sicily

In developed countries, the use of iodised salt represents the best prophylaxis of endemic goitre in areas exposed to iodine deficiency. In the present study we re-evaluated goitre prevalence and iodine intake 10 years after the introduction of iodised salt in an area of goitre endemia in north-eastern Sicily (Italy), and we compared these results with those obtained in previous surveys. Three centres with known moderate goitre endemia (Bronte, Nicosia, and Gagliano) and three other smaller ones with severe goitre endemia (Sperlinga, Villadoro, and Maniace) were studied. We surveyed 697 schoolchildren. Goitre prevalence was assessed by thyroid palpation and by a thyroid ultrasound scan. Iodine urinary excretion was also measured. Iodised salt consumption was 44% of total salt consumption. Goitre prevalence assessed by thyroid palpation was significantly decreased in all towns studied compared to previous surveys. However, the persistence of a mild goitre endemia was observed in some small rural centres (5.8% in Sperlinga/Villadoro, and 11.4% in Maniace). Goitre prevalence evaluated by thyroid ultrasound scan was greater than 5% in all centres of the endemic area and was always greater than that assessed by thyroid palpation. Iodine urinary excretion was above 100 microg/l in all localities studied. In conclusion, our studies indicate a progressive reduction in goitre prevalence over a period of about 30 years in schoolchildren in a well-characterised endemic area in northeastern Sicily. The decrease in goitre prevalence was associated with a significant increase in urinary iodine excretion. However, it may be speculated that iodine deficiency is the pre-eminent, but not the exclusive cause of goitre endemia in this area.

Radiometabolic treatment of hyperthyroidism with a calculated dose of 131-iodine: results of one-year follow-up

Oral administration of radioactive iodine (131I) is a well-known and effective procedure for the treatment of hyperthyroidism. However, the optimal dose is still a matter of debate, as is the frequency of recurrence and hypothyroidism. The aim of our study was to evaluate the 1-yr outcome of a calculated dose of 131I activity in the treatment of hyperthyroidism, following the guidelines published jointly by the Italian Society of Endocrinology and the Italian Society of Nuclear Medicine.We studied 84 patients affected with hyperthyroidism (55 with Graves' disease and 29 with toxic adenoma), who were treated with a dose of 131I activity obtained by using the formula from the guidelines. In all patients serum free T4, free T3, and TSH were measured before, and 2, 6, and 12 months after radiometabolic therapy. A thyroid scan and thyroid uptake with 131I were also performed before treatment, and a thyroid ultrasound scan was obtained before and 1 yr after treatment. One year after treatment, 22 out of 55 patients with Graves' diseases (40.0%) had persistence/ recurrence of hyperthyroidism, whereas only 1 patient of the 29 with toxic adenoma (3.4%) was still in a hyperthyroid state. The frequency of hypothyroidism in patients responsive to therapy was higher in subjects with Graves' disease (45.5%), than in those with toxic adenoma (17.3%, p=0.02). Overall size reduction of the target lesion was 56.2+/-23.1%. In conclusion, the dose calculation suggested by the guidelines represents an effective method for treating thyroid toxic adenoma. In subjects with Graves' disease, we propose using a pre-determined 131I activity, which is higher than that derived from the guidelines. Such an approach would reduce the incidence of recurrent/persistent hyperthyroidism. On the other hand, an increase in post-131I hypothyroidism should not be regarded as a negative effect in these patients, since hypothyroidism is easily corrected, and the risk of worsening ophthalmopathy is reduced.

Acute changes in clinical parameters and thyroid function peripheral markers following L-T4 withdrawal in patients totally thyroidectomized for thyroid cancer

After total thyroidectomy, differentiated thyroid cancer (DTC) patients have to undergo L-T4 withdrawal for measuring serum thyroglobulin and 131I whole-body scan (131I WBS) to evaluate residual/recurrent malignant disease. The aim of the present work was to study in these patients the effects of acute thyroid hormone deficiency on various target organs and tissues. Clinical parameters and thyroid function peripheral markers were evaluated in 20 DTC patients, both before and after L-T4 withdrawal. A 24-h urine collection, a fasting blood sample for laboratory examinations, a clinical score for hypothyroidism and cardiovascular, neurological and neuropsychological evaluations were carried out. After L-T4 withdrawal, the clinical score significantly increased, as well as total cholesterol, triglycerides, creatine kinase, lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase, whereas SHBG, osteocalcin and urine hydroxyproline levels significantly decreased. The acute thyroid hormone deficiency caused a systolic dysfunction of the left ventricle associated with an increase in systemic vascular resistance without cardiac contractility alterations. A significant increase in the left ventricular mass and thickness was also observed. Carpal tunnel syndrome appeared in 30% of patients and a significant reduction in the immediate auditive memorization and in attentive performance was also detected. These observations indicate that acute hypothyroidism causes significant clinical alterations of peripheral tissue function. In the follow-up of DTC patients, therefore, L-T4 withdrawal procedure should be restricted to cases where the cost/benefit ratio is favorable. Alternative procedures, such as the use of recombinant human TSH, should be used whenever possible.

[Iodine deficiency and iodine prophylaxis experience in Sicily]

Twenty years ago we described an area of goiter endemia in North-Eastern Sicily. In this area endemic goiter was associated to a variable degree of iodine deficiency and, in some places, also to an increased thiocyanate urine excretion. Our studies have demonstrated a strict relationship between iodine deficiency and congenital hypothyroidism (both permanent and transient), an increased prevalence of autonomously functioning thyroid nodules and an increased prevalence of thyroid cancer (follicular and anaplastic histotypes). A number of cases of endemic cretinism have also been described. An active iodine prophylaxis program has been carried in the town of Troina in the years 1979-87, by iodinating the municipal water supply. This intervention caused the disappearance of goiter in schoolchildren in only five years. In the last 20 years the prevalence of goiter has decreased in all endemic areas probably because of the "silent prophylaxis", due to improved socio-economic conditions and industrial food consumption. Today the persistence of endemic goiter confirms the inadequacy of the silent iodine prophylaxis and the need to immediately introduce an active iodine prophylaxis in Sicily.

Appearance of anti TSH-receptor antibodies and clinical Graves' disease after radioiodine therapy for hyperfunctioning thyroid adenoma

Radioiodine treatment use is frequent in patients with benign hyperfunctioning thyroid diseases and the side-effects are rare. In this paper we described the appearance of TSH-receptor antibodies and the concomitant development of persistent hyperthyroidism in a patient with hyperfunctioning thyroid adenoma after 131I treatment. A 70-year-old man presented a hyperfunctioning thyroid adenoma with suppressed uptake in the adjacent normal gland. Antibodies against the thyroglobulin (TgAb), thyroid peroxidase (TPOAb) and TSH-receptor (TRAb) were absent. One year after remission by radioiodine therapy the patient developed severe and persistent hyperthyroidism associated with diffuse 131I uptake in the gland. TgAb and TPOAb remained absent, but TRAb were present. Although spontaneous development of Graves' disease cannot be excluded, the time sequence and the negative familial and personal history for autoimmune diseases suggest a possible connection between the two phenomena. The release of TSH-receptor antigen from follicular cells damaged by 131I may have triggered the autoimmune response turning a toxic nodular goiter patient into a Graves' disease patient.

False positive 131I total body scan due to bilateral polycystic renal disease

A radioiodine accumulation at Total Body Scan (TBS) in patient who has been thyroidectomized for a differentiated thyroid cancer is usually a reliable indicator of recurrent or metastatic functioning thyroid tissue. Radioiodine uptake may be usually observed at TBS in areas such as the intestinal tract, liver, salivary glands, bladder, and also in case of blood vessel ectasia. This report describes a patient with a bilaterally significant 131I uptake in upper abdomen. By ultrasound and radionuclide imaging the 131I uptake was proven to be due to radioiodine accumulation caused by bilateral polycystic renal disease.

Longitudinal study on goiter prevalence and goitrogen factors in northeastern Sicily

A longitudinal study was carried out in an area of endemic goiter of north-eastern Sicily. Three different surveys (in 1977, 1983 and 1994) evaluated the epidemiological prevalence of goiter in schoolchildren of the endemic area (towns of Bronte, Troina and Maniaci) in comparison to an iodine sufficient control area (Catania). Biochemical studies were also performed on urinary iodine and thiocyanate (SCN) excretion and 131I thyroid uptake. In the town of Troina an experimental program of active iodine prophylaxis was carried out from 1979 to 1987 by iodinating the municipal water supply. The aim of this study was to evaluate the effect of an active iodine prophylaxis program in comparison to the "silent iodoprophylaxis" due to improved economic conditions and widespread introduction of industrially produced food. In the 1977-94 period a significant decrease of goiter prevalence in schoolchildren was observed in all areas where no active iodoprophylaxis had been introduced. An abnormal prevalence of goiter, however, was still present in Bronte (12.1%) and Maniaci (25.9%) schoolchildren in respect to Catania (0.7%). In Troina, goiter prevalence decreased from 52.2 to 6.1% after only five years of active iodine prophylaxis (1983). It increased to 8.4% seven years after the program was discontinued (1994). In all areas studied average urinary iodine excretion increased by 70-100 micrograms/day except in the more rural area at Maniaci. During the same period urinary SCN values decreased by 30-40% and were lower in Troina (non volcanic soil) than in other towns studied. The balance between iodine and SCN intake appears a relevant factor in the etiology of endemic goiter in these areas and the iodine/SCN ratio inversely correlated with goiter prevalence. The persistence of endemic goiter in spite of the important changes in life style and socio-economic conditions if compared to the dramatic amelioration obtained by an active iodine prophylaxis program, confirms the inadequacy of the silent iodine prophylaxis, and further supports the need of an immediate introduction of active iodine prophylaxis in the areas of endemic goiter in Sicily.

Three new mutations of thyroid hormone receptor-beta associated with resistance to thyroid hormone

Three novel point mutations at nucleotides 1249, 1282, and 1614 (exons 9 and 10) of the human thyroid hormone receptor-beta gene were observed in six individuals affected by the syndrome of resistance to thyroid hormone. All three mutations occurred in a heterozygous pattern and caused the following changes in the mature form of the receptor protein: Asp322 to Asn, Glu333 to Gln, and Lys443 to Asn, respectively. The first and third point mutations arose in two unrelated families from eastern Sicily, whereas the second concerned an individual from southern Calabria, apparently presenting a sporadic form of the resistance syndrome. The clinical and biochemical features of resistance to thyroid hormone, both before and after the administration of thyroid hormones, highlight the striking intrafamilial heterogeneity in the phenotypical presentation of the syndrome.

[Physiopathology of the autonomous thyroid nodule]

"Autonomous" thyroid nodule is a localized nodular lesion of the thyroid gland characterized by growth, iodine uptake and function, all independent from TSH control. These nodules represent a heterogeneous anatomic and clinical entity. The clinical diagnosis is based upon a negative suppression of nodule iodine uptake and scan imaging by T3 administration. The nodule function is determined by high serum thyroid hormone levels and/or low TSH (measured by ultrasensitive assay). Etiology and pathogenesis of these nodules is not yet completely clarified. Both genetic and environmental factors determine nodule growth and function: thyroid cells, in fact, are genetically heterogeneous and may have intrinsic (congenital) characteristics that may promote the growth of cellular clones having mitotic and functional activity that is partially independent of TSH. In these particular cell clones, environmental factors like iodine deficiency or other goitrogens may favour the growth of autonomous nodules and also, by activating their function, may induce toxicity. The autonomous thyroid nodules need to be treated only when they become toxic: in this case both surgical excision or radioiodine may be used.

False positive 131I total body scan due to an ectasia of the common carotidis

A cervical accumulation of radioiodine at Total Body Scan (TBS) in a patient who had been thyroidectomized for a follicular thyroid carcinoma led to unnecessary radioiodine treatment. Thyroglobulin measurements indicated constantly low levels. Following ultrasound scanning of the neck, echo-doppler examination of the cervical vessels and angiography with 99Tc, this area of increased activity at TBS imaging was shown to be due to an ectasia of the right common carotidis causing blood stasis and reverse flow.

Cancer risk in patients with cold thyroid nodules: relevance of iodine intake, sex, age, and multinodularity

PURPOSE

We evaluated the frequency of thyroid cancer in patients with cold thyroid nodules in relation to iodine intake, sex, age, and multinodularity in a consecutive series of patients with nodular thyroid diseases.

PATIENTS

In the period from 1980 to 1990, 5,637 patients were studied: 4,176 patients were from an iodine-sufficient area (ISA) and 1,461 from an adjacent iodine-deficient area (IDA). Surgery was performed in 792 patients on the basis of a suspicious or malignant finding at fine-needle aspiration biopsy.

RESULTS

The overall thyroid cancer frequency was 4.6% (259 patients had cancer). Iodine intake affected the cancer rate in patients with cold nodules. The frequency of cancer in patients with cold thyroid nodules was 5.3% in the ISA and 2.7% in the IDA. This difference, however, was significant only in females. Sex had a major influence on the malignant rate of cold nodules; although female patients were more frequently observed (n = 5,028) than male patients (n = 609), the frequency of cancer was significantly lower in female patients with cold nodules (4.2%) than in males (8.2%). Age was an important factor in both sexes. The proportion of nodules that were malignant was smallest in patients of the 4th decade and was greatest in patients younger than 30 years or older than 60 years. Multivariate analysis showed that sex and age interact in determining the cancer risk in patients with thyroid nodules. Finally, the frequency of thyroid cancer in patients with a solitary nodule was not different from the frequency in patients with multiple nodules.

CONCLUSION

Our study indicates that thyroid cancer risk in a patient with a nodular goiter varies markedly according to iodine intake, sex, and age but not in relation to multinodularity, as assessed by clinical examination. The knowledge of these epidemiologic aspects of thyroid cancer may increase the accuracy of the preoperative selection of patients with cold nodules of the thyroid.

Ultrasound scanning assessment of L-thyroxine treatment effectiveness in a group of children with diffuse goiter

Ultrasound scanning is an accurate and objective method to assess thyroid volume; therefore it is useful to evaluate the effectiveness of L-thyroxine treatment in reducing goiter size, especially in children where clinical evaluation is inaccurate. In this prospectic study we evaluated the effectiveness of one-year L-thyroxine treatment in a group of children with nontoxic diffuse goiter coming from an area with low iodine intake. We examined 11 children (7 females, 4 males), age range 9-14 years. At clinical examination, 6 patients had a goiter classified Ia (according to WHO criteria), 4 had a class Ib and only 1 had a class II goiter. In order to achieve an accurate goiter evaluation, the thyroid volume was determined by ultrasonic scanning with a 5 MHz linear probe before and after treatment. Patients were given a dose of L-thyroxine (1.5-2.0 micrograms/kg/die) in order to significantly reduce serum TSH levels (from 1.8 +/- 0.6 to 0.8 +/- 0.5 mU/l, mean +/- SD). Patients were reexamined at 12 months of therapy and again at 10 months after therapy withdrawal. A significant reduction of the goiter volume (greater than 20%) was obtained in 6/11 (54%) patients, although serum TSH levels were fully suppressed only in one. The mean goiter size reduction in "responders" was -31.2 +/- 9.3% (m +/- SE). After therapy withdrawal goiter size increased in the majority of cases (in 4/11, greater than 20%). Our study demonstrates that L-thyroxine treatment is effective in reducing goiter size in the majority of children with a diffuse goiter.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytogenetic analysis in congenital hypothyroidism

In order to evaluate the possible role of genetic factors in the pathogenesis of congenital hypothyroidism (CH), we investigated the occurrence of chromosome aberrations in a consecutive series of 47 patients with CH and 208 matched healthy controls. No abnormal karyotype was found in CH patients. In 5 CH patients and in 3 healthy controls a number of heterochromatin variants was detected. Although chromosomal variants are devoid of phenotypic effects, the frequency of these variants was higher in CH patients than in the control group (10.6% vs 1.4%, p less than 0.005). These findings suggest that the association of congenital hypothyroidism with chromosomal variants may reflect more than chance concurrence.

Epidemiology and clinical characteristics of endemic cretinism in Sicily

In this study we report the prevalence of endemic cretinism in the general population of two iodine deficient areas in Northeastern Sicily that were described more than 10 yr ago. In addition, the individual characteristics of endemic cretins are considered in order to define the typical expressions of this major iodine deficiency disorder in Sicily. Forty-three mental defectives were identified: 22 were living in an area with three bordering and closely connected municipalities within the province of Messina and with a population of 17,485 inhabitants (prevalence = 0.13%). Three out of the 22 were school-age children. The other community, in the province of Catania, was constituted by a unique and mostly agricultural hamlet, and showed a prevalence of cretinism that was 0.68% (21/3,100). Among the 43 mental defectives, 16 (37%) presented prominent neuromotor and neurosensorial disorders, including deafmutism and were euthyroid, thus conforming to the neurological type of cretinism; 13 (30%) were hypothyroid and exhibited stunted growth without significant neuromotor and neurosensorial impairment (myxedematous cretins). In the remaining 14 individuals (33%) neurological disorders were associated with stunted growth and clinical or biochemical hypothyroidism. These data indicate that also in Sicily endemic cretinism is a continuum of a variety of forms: among these the pure neurological and pure myxedematous forms represent the two extremes. Our observations also indicate that endemic cretinism still represents a major public health problem in Sicily. The finding of 3 endemic cretins younger than 13 yr suggests the persistence of this disorder even in the presence of improved economic, social and nutritional conditions.

Electrochemical behavior of some commercial dental amalgams in artificial saliva

Cathodic, linear anodic, and anodic polarization studies conducted on three commercial dental amalgams, Caulk Fine Cut Alloy, Spheralloy, and Dispersalloy, showed that all amalgams were in a passive state at the corrosion potential in synthetic saliva solution. The corrosion currents at the corrosion potential were therefore small for all the amalgams, in the range 0.08 to 0.30 muA/cm2. However, the Caulk Fine Cut Alloy and Spheralloy amalgams exhibited a breakdown of passivity and high anodic currents at potentials only approximately equal to 100 mV more noble than the corrosion potential whereas Dispersalloy amalgams maintained passivity at potentials up to 700 mV more noble than the corrosion potential. The breakdown of passivity in Caulk Alloy and Spheralloy amalgams is attributed to the presence of the gamma2 phase (Sn7-8Hg) whereas the passive behavior of Dispersalloy amalgam is attributed to the absence of the phase. It is concluded that none of the amalgams will exhibit severe general corrosion in use, but that both Caulk Alloy and Spheralloy amalgams will exhibit pitting corrosion whereas this type of corrosion should be minimal in Dispersalloy amalgams.