Ontogeny of nyctohemeral variations of thyrotropin-releasing hormone in rat hypothalamus.

The ontogeny of nyctohemeral variations of hypothalamic TRH content was determined in male rats from 7-45 days after birth, exposed to a daily 12-h light, 12-h dark cycle (0600-1800 h light; 1800-0600 h dark) or maintained in complete darkness until 45 days. TRH was extracted from whole hypothalami with 90% methanol and assayed by specific RIA. Hypothalamic TRH extracted from rats at different ages showed immunological, chromatographic, and biological properties identical to those of synthetic TRH. No significant variations in hypothalamic TRH content during the day were observed in 7-, 10-, and 17-day-old rats; a significant change, with a maximal value at 1800 h, was observed in 23-day-old rats, while an adult pattern with a maximal value at 1200 h and a minimal value at 2400 h was found in rats of 31 days of age and became more evident in 45-day-old rats. In animals maintained in complete darkness for 45 days after birth, no significant changes in hypothalamic TRH content at 1200 and 2400 h were observed. These findings indicate that environmental cyclic light-dark exposure is required for the development of diurnal changes in hypothalamic TRH content. Furthermore, any study involving hypothalamic TRH determination should take into account the age of animals and the diurnal variations of TRH.

Solubilization of human thyroid microsomal antigen.

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.

Dissociation of responsiveness to thyrotropin-releasing hormone and thyroid suppressibility following antithyroid drug therapy of hyperthyroidism.

Responsiveness to synthetic thyrotropin-releasing hormone (TRH), thyroid suppressibility by triiodothyronine (T3) and the outcome of hyperthyroidism following prolonged therapy with thionamides were studied in a group of 35 patients with toxic diffuse goiter. TRH and T3 suppression tests were performed 10 days to 24 months (mean 4 months) after withdrawal of antithyroid drugs. Nineteen patients were euthyroid and had a normal thyrotropin (TSH) response to TRH, while 4 were recovering from mild hypothyroidism due to overtreatment and had an exaggerated response. No response was observed in 12 patients with recurrent hyperthyroidism. Positive T3 suppression tests were found only in 10 of the 30 cases examined. Peak and net 2 h secretion responses of TSH to TRH exhibited a significant inverse correlation with the levels of serum thyroxine and serum triiodothyronine, but were unrelated to the degree of thyroid suppressibility. Relapse or recurrence of thyrotoxicosis occurred in at least 9 of the 23 patients having no evidence of hyperthyroidism at the time of TRH test. Each of them was found to be responsive to TRH, while the T3 suppression test was negative in 8 and had to be discontinued in one because of thyrotoxic symptoms. The present data indicate that during the early period after completion of a prolonged course of antithyroid drug therapy responsiveness to TRH in toxic diffuse goiter is: a) correlated with circulating thyroid hormones, b) unrelated to the degree of thyroid suppressibility by T3 and c) of little value in predicting the long-term results of treatment.

Orbital cobalt irradiation combined with systemic corticosteroids for Graves' ophthalmopathy: comparison with systemic corticosteroids alone.

The effects of different methods of treatment of Graves' ophthalmopathy were evaluated in a series of 48 patients. Thirty-six patients were given combined treatment with orbital cobalt irradiation and systemic 6 alpha-methylprednisolone (methylprednisolone). Included in this group were 12 of 24 consecutive patients who were randomly assigned to either combined therapy or systemic methylprednisolone alone. The degree of ocular involvement and responses to treatment were evaluated by numerical scoring (ophthalmopathy index) and clinical assessment. Of the 36 patients treated by combined therapy, 12 (33%) showed excellent responses, 14 (39%) showed good responses, 9 (25%) showed slight responses, and 1 (3%) had no response. Treatment was more effective for soft tissue involvement, newly developed ophthalmoplegia, and optic neuropathy, while proptosis and longstanding ophthalmoplegia were less responsive. There was an inverse relationship between the duration of ophthalmopathy and the efficacy of treatment, more favorable results being observed when symptoms had been present for less than 2 yr. Treatment with systemic methylprednisolone alone was also effective, but, in general, responses were less satisfactory; 4 of the 12 patients of this group (33%) had good responses, 6 (50%) had slight responses, and 2 (17%) had no response. The results obtained in the 24 patients randomly assigned to combined therapy or steroid treatment alone were compared by evaluating changes in the ophthalmopathy index. Mean initial ophthalmopathy indices (6.4 vs. 6.2, respectively) showed no significant differences between the 2 groups, whereas the mean decrease in the group receiving combined therapy (4.8) was significantly greater (P less than 0.05) than that in the other group (3.2). In conclusion, the present study indicates that both orbital cobalt irradiation combined with systemic methylprednisolone treatment and systemic methylprednisolone therapy alone are valuable methods of treatment for Graves' ophthalmopathy, but the combined therapy proved to be more effective.

Percutaneous aspiration and ethanol sclerotherapy for thyroid cysts.

Benign thyroid cysts often recur after aspiration; the effectiveness of tetracycline instillation in the case of recurrence has been questioned. We, therefore, tested the efficacy of percutaneous ethanol injection in 20 patients with "pure" cyst relapsing after aspiration. After evacuation, 95% ethanol was instilled under sonographic guidance and re-aspirated 5 min later. The procedure was performed twice for larger cysts. Follow-up studies were carried out after 1, 3, 6, and 12 months. In case of recurrence at 1 month, patients (n = 5) were submitted to a second session. A slight burning sensation was the only adverse effect. No recurrences were observed at 3 and 6 month follow-up; only one patient with recurrence after 1 month had relapsed at 12 months. A significant shrinkage (P < 0.0001 vs. pretreatment) was observed in all other cases at 12 months; cysts were not detectable in seven patients (35%). No significant variations in thyroid hormone levels were detected during treatment or follow-up. Serum thyroglobulin levels markedly increased 3 h after ethanol injection. One month after treatment, thyroglobulin returned to pretreatment levels, thus excluding progressive thyroid damage. Percutaneous ethanol injection may prove a safe and effective tool for the therapy of thyroid cysts.

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.

Twenty-four hour radioactive iodine uptake in 35 patients with amiodarone associated thyrotoxicosis.

Amiodarone associated thyrotoxicosis (AAT) occurs in approximately 10% of patients treated with this iodine rich drug in areas of mild iodine deficiency. The thyroid radioactive iodine uptake (RAIU) is usually undetectable or very low in iodine-induced thyrotoxicosis. In the present study, 35 patients with AAT were evaluated. Twelve patients had no thyroid abnormalities by physical exam and all had 24-hr RAIU less than or equal to 4%. In contrast, nine of 11 patients with AAT and diffuse goiters and eight of 12 patients with AAT and nodular goiters had RAIU values greater than 8%. In patients with AAT and goiter it appears possible that the thyroid fails to adapt normally to the excess iodide load, resulting in an inappropriately high RAIU in the presence of excess plasma iodine.

Serum myoglobin in primary hypothyroidism and effect of L-thyroxine therapy.

Serum myoglobin (Mb) concentrations have been measured by radioimmunoassay in normal subjects, in hypothyroid patients examined 20 days after withdrawal of thyroid hormone therapy ("short-term" hypothyroidism), and in untreated hypothyroids ("long-term" hypothyroidism). In "short-term" hypothyroids, serum Mb levels were significantly higher (p less than 0.01) than those observed in normal controls, although only a minority or patients showed elevated Mb levels. In "long-term" hypothyroids, serum Mb concentrations were significantly higher than that found in normal controls (p less than 0.0001) and in "short-term" hypothyroids (p less than 0.001). In "long-term" hypothyroidism a significant inverse correlation was found between serum thyroid hormones and Mb, whereas no similar correlation was observed in "short-term" hypothyroidism. The administration of progressively increasing doses of L-T4 untreated hypothyroids was followed by normalization of serum Mb, but serum TSH levels still remained elevated. These data indicate that the duration and the severity of hypothyroidism are important factors in the rise of serum Mb, and that the normalization of serum Mb is faster than that of serum TSH and requires less L-T4 than that needed for normal TSH secretion.

Prospective, randomized, double-blind study about effectiveness of levothyroxine suppressive therapy in prevention of recurrence after operation: result at the third year of follow-up.

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.

Somatostatin effect in postprandial hypoglycemia.

The effect of the administration of oral glucose with or without a simultaneous intravenous somatostatin infusion on blood glucose, immunoreactive insulin, C-peptide, and glucagon levels in seven patients with idiopathic postprandial hypoglycemia was studied. Oral glucose alone induced an excessive insulin response and hypoglycemia, whereas a slight suppression in glucagon levels without any increase at the hypoglycemic nadir was observed. The simultaneous administration of somatostatin significantly reduced the insulin response and induced a slower rise of blood glucose; no hypoglycemia developed. Only minor variations in glucagon were observed with respect to the basal test. A rebound in insulin, C-peptide, and glucagon levels was observed at the end of the somatostatin infusion. These data show that somatostatin can suppress glucose-induced hypoglycemia in these subjects, thus suggesting that its long-acting analogues might be worth a therapeutic trial in severe idiopathic postprandial hypoglycemia.

Completion total thyroidectomy in children with thyroid cancer secondary to the Chernobyl accident.

OBJECTIVE: To evaluate the usefulness of submitting children with thyroid cancer secondary to nuclear accidents to a completion total thyroidectomy. DESIGN: A case series consisting of patients living and operated on in Belarus whose parents had asked for a clinical evaluation in a western European center. SETTING: A tertiary care referral center. PATIENTS: The conditions of 47 children from Gomel, Belarus, with differentiated thyroid carcinoma following the nuclear accident at Chernobyl, Ukraine, were evaluated at the University of Pisa, Pisa, Italy. In approximately half of the cases, the treatment in Belarus consisted of a hemithyroidectomy. After a complete evaluation, the decision was made to reoperate on 19 of them by performing a completion total thyroidectomy. The preoperative evaluation revealed that 5 (26%) of the 19 patients who had undergone a hemithyroidectomy had unilateral recurrent nerve palsy and that 2 (10.5%) had hypoparathyroidism. INTERVENTIONS: Neck ultrasonography was used for the preoperative localization of thyroid residuals, thyroid nodules, suspicious lymph nodes, and a guided fine-needle aspiration biopsy specimen. The circulating thyroglobulin measurement was obtained before reoperation. An iodine 131 whole-body scan (WBS) was performed and circulating thyroglobulin levels were obtained after completion of the thyroidectomy during withdrawal of levothyroxine sodium therapy. MAIN OUTCOME MEASURE: The number of patients with a recurrence of thyroid cancer and lung or lymph node metastases after the completion total thyroidectomy. RESULTS: The results of the histologic examination were positive for papillary thyroid cancer in 6 (28.6%) of 21 patients, 3 with residual cancer in the remaining thyroid lobe and 3 with metastatic lymph node disease. A posttherapy WBS demonstrated lung metastases in 5 (28%) of 18 patients and lymph node metastases in 6 (33%) of 18 patients; the results of a posttherapy WBS were negative for metastases in 7 (39%) of 18 patients. Hypoparathyroidism developed in 4 (21%) of 19 patients who underwent a completion total thyroidectomy; unilateral laryngeal nerve palsy developed in 1 (5.2%) of these 19 patients. Among 22 children who previously underwent total thyroidectomy in Belarus, a diagnostic WBS showed lung metastases in 10 (45%) of the children and lymph node metastases alone in 3 (14%) of the children; the results of a diagnostic WBS were negative for metastases in 9 (41%) of the children. Statistical analysis showed a nonsignificant (P>.05) difference in the prevalence of lung and lymph node metastases in patients who previously underwent total thyroidectomy compared with patients who underwent completion total thyroidectomy. CONCLUSION: Completion total thyroidectomy allowed for the diagnosis and treatment of recurrent thyroid cancer and lung or lymph node metastases in 61% (11/18) of the patients in whom residual differentiated thyroid carcinoma was not previously recognized.

Treatment of the carcinoid syndrome with somatostatin, salmon calcitonin, or octreotide.

Three patients with the carcinoid syndrome received intravenous somatostatin (3.5 micrograms/min) for one day; intravenous salmon calcitonin (8 IU/hr) for one day; subcutaneous salmon calcitonin (100 IU three times daily) for ten days; and subcutaneous octreotide (150 micrograms three times daily) for ten days. Octreotide (SMS-201.995) is a stable analogue of somatostatin. There was a five-day washout period between each treatment. During each of these treatments, reductions in the numbers of daily flushes and bowel movements, stool weight, and urinary 5-hydroxyindoleacetic acid (5-HIAA) levels were observed. Relief of cramping abdominal pains was also reported. Patients 1 and 3 chose to continue receiving the subcutaneous calcitonin and patient 2 chose the octreotide. Patient 1 (aged 67 years) reported relief of symptoms for five months until she developed an intestinal obstruction as a result of tumor infiltration. Patient 3 (aged 67 years) has received the calcitonin for about 16 months with relief of symptoms and reduced urinary 5-HIAA levels. Patient 2 (aged 57 years) has continued octreotide treatment for one year and reports relief of symptoms.

Intravenous immunoglobulin versus corticosteroid in treatment of Graves' ophthalmopathy.

We compared the effectiveness of systemic corticosteroids with the use of high-dose intravenous immunoglobulin (IVIG) in the treatment of Graves' ophthalmopathy. This was performed as a prospective, nonrandomized study including a blinded ophthalmological and orbital computed tomographic (CT) evaluation. The two groups of patients were not significantly different in relation to sex composition, age distribution, duration of Graves' disease, and ophthalmopathy and previous hyperthyroidism. All patients were followed up by endocrinologic evaluation and blinded ophthalmological (before therapy = B, at the end of therapy = E, and 6 months after the end = 6M) and orbital CT (B and E) evaluations. Twenty-seven patients treated with IVIG were followed up after the end of treatment for an average of 21 months (range 12 to 48 months). Soft tissue involvement (NOSPECS) improved or disappeared in 32 of 35 (90%) patients treated with IVIG and in 25 of 27 (92.5%) patients treated with corticosteroids. Diplopia improved or disappeared in 22 of 29 (75%) patients treated with IVIG and in 16 of 20 (80%) patients treated with corticosteroids. The results observed by clinical evaluation were confirmed with orbital CT score in 30 IVIG patients and in the corticosteroid-treated patients; a significant reduction of extraocular muscle thickness was observed after treatment in both groups. Proptosis improved or disappeared in 20 of 31 (65%) patients treated with IVIG and in 15 of 24 (62%) patients treated with corticosteroids. Mean values of proptosis evaluated by Hertel's exophthalmometer showed a slight reduction both in IVIG as well as in corticosteroid-treated patients. It is interesting to observe that in 28 IVIG-treated patients in whom it was possible to evaluate soft tissue involvement, proptosis and diplopia in the period between the fifth and sixth month from the start of therapy, the most important part of the amelioration (if responders) was already obtained at that time. Responder patients were defined in relation to the decrease in the highest NOSPECS class or grade. Among IVIG-treated patients 26 of 34 (76%) responded; while in the corticosteroid group 18 of 27 (66%) responded to treatment. The prevalences of patients who responded to the treatments were not significantly different in the two groups (Chi-square). The initial values of the subjective eye score were similar in the two groups, and a significant reduction was observed in both. Major side effects requiring discontinuation of the corticosteroid therapy were observed in two patients with hemorrhagic gastritis and in one patient with manic-depressive psychosis. Among 15 patients submitted to the evaluation of bone mineral content before and after corti-costeroid therapy, 4 presented signs of osteoporosis and 3 a reduction of bone mineral content. Moderate and minor side effects were more frequently noted in steroid-treated patients than in the IVIG group. These data suggest that IVIG is safe and effective in reducing the eye changes in patients with Graves' ophthalmopathy.

Pretibial myxedema and high-dose intravenous immunoglobulin treatment.

Seven patients affected by Graves' ophthalmopathy and pretibial myxedema (four patients with nodular form, two with diffuse, and one with elephanthiasic form) have been treated with high-dose intravenous immunoglobulins. We have observed (a) clinical improvement of pretibial myxedema and Graves' ophthalmopathy in all patients, (b) a reduction of pretibial skin thickness, by ultrasonography evaluation, in four patients, (c) a reduction of mucopolysaccharide skin content in three patients, (d) disappearance of lymphocytic skin infiltration and IgG deposition in two patients, and (e) a parallel reduction of the titer of circulating autoantibodies as antithyroglobulin, antimicrosomal, anti-TSH receptor, and of non-organ-specific antibodies as antinuclear, anti-smooth muscle cells, and anti-mitochondrial. In comparison two patients with Graves' ophthalmopathy and pretibial myxedema treated with systemic corticosteroids did not present any improvement of the cutaneous ailment. Therefore, this study suggests that intravenous immunoglobulins are effective in the treatment of pretibial myxedema and may have an immunomodulant action in patients with Graves' disease and related disorders.

Clinical picture of endemic cretinism in central Apennines (Montefeltro).

Endemic cretinism is still present in an endemic goiter area of the central Apennines (Montefeltro) (goiter prevalence 55%; mean urinary iodine level 39 micrograms/g creatinine). Clinical and biochemical features of patients with myxedematous, neurologic, and mixed cretinism were studied. Also, in this area, as in most other, neurologic cretinism is more prevalent than myxedematous and mixed forms. The hormonal profiles of the three types of cretinism were clearly different. Nevertheless, all myxedematous cretins had some neurologic disorders (hyperreflexia, increased muscle tone, disorder of gait, Babinski sign, hypoacusia) that were similar to those present in neurologic cretins. These findings suggest that neurologic damage is very similar in all forms of endemic cretinism, reflecting a diffuse insult to the developing fetal nervous system. Furthermore, these data support the hypothesis that the primary pathophysiologic event in the different types of endemic cretinism is represented by maternal and fetal hypothyroidism, while differences may be explained by the extent and duration of postnatal hypothyroidism. All the cretins were over 35 of age, suggesting a severe iodine deficiency in the past decades, and a progressive improvement of nutritional status resulted in "silent iodine prophylaxis." However, recent studies have revealed the persistence of a moderate iodine deficiency, a high prevalence of neurologic hypoacusia, and reduction of mental performance in normal schoolchildren of this area. These findings constitute strong evidence in favor of adequate iodine prophylaxis.

Role of neck ultrasonography in the follow-up of patients operated on for thyroid cancer.

The aim of the study was to evaluate the role of neck ultrasonography in follow-up of patients with differentiated thyroid cancer. Sixty-three patients had total thyroidectomy and 131I ablation for differentiated thyroid cancer and had a negative whole body scan during follow-up. They were admitted for a high resolution neck ultrasound examination. Sixteen of 63 patients presented images suspicious for lymph node metastasis and/or for local recurrences (4 cases). Fine needle aspiration confirmed the suspicion of malignancy in 12 patients: only lymph node metastasis in 8 cases, local recurrence and lymph node metastasis in 3 cases, and in one case only local recurrence. Fine needle aspiration was suspicious for lymphadenitis in 4 cases. Thyroglobulin levels were very high in all patients with local recurrence and/or lymph node metastasis but undetectable in 2 cases presenting node metastasis and in 4 cases with lymphadenitis. All but one patient were admitted for surgery and the cytological diagnosis was confirmed. Early identification of a pathologic mass in the neck is a desirable goal; high resolution echography can play an important role in the follow-up of these patients and can detect local recurrences even when there is a negative whole body scan or undetectable thyroglobulin level.

Effect of 2-deoxy-D-glucose on hypothalamic-pituitary-thyroid axis in rats.

The intraperitoneal administration to rats of 500 mg/kg body weight of 2-deoxy-D-glucose, an analog of glucose which produces intracellular glucopenia with rise in extracellular fluid glucose concentration, is followed by a significant though transient reduction of hypothalamic TRH content, observed at 15 and 25 minutes after drug administration. A subsequent increase in serum thyrotropin followed by that of triiodothyronine concentration was also observed. These findings indicate that the neuroglucopenia induced by 2-deoxy-D-glucose may play a role in the regulating the hypothalamic-pituitary-thyroid axis.

IgG, IgA and C3 deposits in the extra-thyroidal manifestations of autoimmune Graves' disease: their in vitro solubilization by intravenous immunoglobulin.

OBJECTIVE: To study the involvement of antibodies in the extrathyroidal manifestations of autoimmune Graves' disease, we determined the presence of IgG, IgA and IgM antibodies and C3c in connective tissue samples from patients with Graves' disease and pretibial myxedema (PTM) or thyroid associated ophthalmopathy (TAO). METHODS: Connective orbital tissue samples were obtained from 12 patients undergoing orbital decompression for TAO, and skin samples from lesions on the pretibial area were obtained in 7 patients with PTM. Sections from each tissue sample were stained with fluorescin-isothiocianate conjugated anti-human IgG, IgA, IgM and C3c and were examined by a fluorescence optical instrument. Other serial sections from each sample were incubated with human IgG solutions (concentration 6 mg/ml or 20 mg/ml), human albumin (40 mg/ml), PBS, myoglobin (40 mg/ml), or IgA (20 mg/ml), and were then processed by a standard direct immunofluorescence staining procedure. RESULTS: Among the samples from TAO patients 8/12 (67%) were positive for IgG deposition, 4/9 (44%) were positive for IgA, 1/9 (11%) was positive for IgM and 4/9 (44%) were positive for C3c deposition. Orbital connective samples from 3 non-TAO patients were all negative. Among samples from PTM patients 4/7 (57%) were positive for IgG deposition, 3/ 4 (75%) were positive for IgA, 0/4 was positive for IgM and 3/7 (43%) were positive for C3c deposition. Skin samples from 5 control patients undergoing skin biopsy for non-autoimmune diseases were all negative. Incubation with human IgG (20 mg/ml) resulted in the complete disappearance of IgG and C3c deposition in all positive patients. No significant variation in IgG fluorescent staining after incubation with either 6 mg/ml of IgG solution, human albumin, PBS, myoglobin or IgA was observed. CONCLUSION: The results of our study suggest that different classes of antibodies, mainly IgG and IgA, may be implicated in the disease process in autoimmune TAO and PTM. Activation of the complement cascade, via the classic or the alternative pathway, could take place in about 40% of these patients. IVIG in vitro may solubilize, by a specific mechanism, IgG and complement immune complex deposition in the extrathyroidal manifestations of autoimmune Grave's disease.

Lack of nocturnal serum thyrotropin (TSH) surge in patients with chronic renal failure undergoing regular maintenance hemofiltration: a case of central hypothyroidism.

Thyrotropin (TSH) secretion was evaluated in a group of patients with chronic renal failure (CRF) undergoing regular maintenance hemofiltration and in normal controls. The study group included 68 patients (39 males and 29 females, age range 39-73 years, mean: 53 years). In all patients blood was drawn at 08:30-09:00 h; in 20 patients the nocturnal (24:00-02:00 h) serum TSH peak was also evaluated; 12 patients underwent stimulation test with synthetic TSH-releasing hormone (TRH). TSH was measured by an ultrasensitive immunoradiometric assay. CRF patients showed a significant decrease in serum total and free thyroxine and triiodothyronine concentrations, which in a substantial proportion of subjects were below the lower normal limit. Serum reverse triiodothyronine and thyroxine-binding globulin values did not differ in the two groups. Despite this trend of thyroid hormones to decrease, no patient had supranormal TSH values as in primary hypothyroidism. While the mean morning TSH concentrations of CRF patients did not differ from those of controls, the mean nocturnal values were significantly reduced in CRF (1.0 +/- 0.2 vs 3.2 +/- 0.4 mU/l, p less than 0.0005) and the nocturnal serum TSH surge was not observed in 18 of the 20 patients (90%) in whom it was evaluated. The mean serum TSH peak value after TSH-releasing hormone (TRH) administration was also reduced in CRF patients, and the TSH response to TRH was blunted in 3 out of 12 patients (25%). The results of this study demonstrate a major impairment of TSH secretion in CRF, which baseline TSH measurements in the morning and the evaluation of the TSH response to TRH may not reveal.(ABSTRACT TRUNCATED AT 250 WORDS)

[Preclinical hypothyroidism: early involvement of memory function, behavioral responsiveness and myocardial contractility]. / Ipotiroidismo preclinico: precoce interessamento delle funzioni mnestiche, della reattività comportamentale e della contrattilità cardiaca.

Subclinical hypothyroidism in characterized by elevated TSH levels in the face of normal thyroid hormone concentrations. The purpose of this study was to evaluate whether these subjects show alterations of neuropsychological and behavioural features and of myocardial contractility as patients with overt hypothyroidism do. We evaluated in 14 subjects the hormonal profile (total and free T3 and T4, TSH), memory ability (Wechsler Memory Scale), behavioural reactivity (Crown & Crisp Experimental Index) and the pre-ejection period (isometric systole). We found an evident impairment of some cognitive functions correlated to memory and a behavioural alteration, perhaps secondary to the disease state, and moreover an early defect of myocardial contractility, represented by prolonged pre-ejection period. These results suggest that these patients should be treated with adequate doses of L-Thyroxine, like in overt hypothyroidism.