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Biomedical subjects

F Monzani

Publications and source records attributed to F Monzani.

51 records · Page 3Linked to original sources
PubMed1990

Effect of fenfluramine on prolactin and thyroid-stimulating-hormone response to thyrotropin-releasing-hormone in obese and normal women.

In order to demonstrate the suggested failure of the serotoninergic system in human obesity and to evaluate the role of central serotoninergic activity in prolactin (PRL) and thyroid stimulating hormone (TSH) release in this condition, 13 euthyroid obese and 9 healthy women of normal weight were studied. A TRH test (200 micrograms i.v.) was performed before and after administration of fenfluramine (FF) 60 mg b.d. for 14 days. In the controls, FF did not modify the expected significant increase in PRL induced by TRH. In obese patients, however, the PRL levels was significantly increased after TRH, but the increase was less than in the controls. After FF, the PRL response to TRH was larger than in the pretreatment phase, with values similar to those observed in normal subjects. In neither group FF did change the TSH-stimulating effect of TRH, but the hormonal response in obese patients was greater than in the controls. The restoration of the responsiveness of PRL to TRH after central serotoninergic stimulation confirms the hypothesis that a failure of the serotoninergic system may occur in human obesity. Since FF does not interfere with the secretory pattern of basal and stimulated TSH in normal or obese subjects, the serotoninergic system does not seem to play a major role in the control of TSH secretion.

Adult↗
PubMed1990

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)

Adult↗
PubMed1985

Reciprocal changes of serum thyroglobulin and TSH in residents of a moderate endemic goitre area.

Subjects living in iodine deficient areas were reported to have elevated serum thyroglobulin (Tg) concentrations. This finding was interpreted as related to thyroid stimulation. Discrepant results, however, were found when serum Tg concentrations were correlated either with serum TSH or with goitre size. In this study we investigated the relationships between goitre size, serum Tg and serum TSH in 488 unselected adult subjects living in an endemic area of North-Western Tuscany (Garfagnana district). The control group comprised 352 subjects residing in a non-endemic area. In the endemic area a high prevalence of goitre was found (80.1%), thyroid enlargement being slight to moderate in the majority of cases and very large only in six subjects. Serum Tg concentrations increased and serum TSH levels decreased with the size of goitre. Statistical analysis by the chi-square cross correlation test showed that the converse changes of serum Tg and serum TSH in relation to goitre size were highly significant. These findings indicate that the increase of serum Tg occurring in endemic goitrous subjects may be related to factors other than TSH stimulation. Functional autonomy of the thyroid may account for the finding of low serum TSH and elevated serum Tg values in patients with large goitres. The present data do not exclude the possibility that the release of Tg is influenced by TSH stimulation, but indicate that other factors may be responsible for the increased levels of Tg found in endemic goitre.

Adult↗
PubMed1983

TSH-displacing activity versus TSH-binding inhibiting activity of immunoglobulins from patients with Graves' disease.

Inhibition of binding of TSH to thyroid plasma membranes by immunoglobulins G (IgG) from patients with Graves' disease has been interpreted as evidence of an interaction with the TSH receptor, but other explanations may account for this phenomenon. Displacement of receptor-bound TSH might be a more direct index of such an interaction. The aim of the present study was to assess TSH-displacing activity (TDA) of Graves' IgG by a newly developed assay and compare TDA to TSH-binding inhibiting activity (TBIA) and thyroid-stimulating antibody (TSAb) activity. TDA was assessed by preincubating 125I-TSH with thyroid plasma membranes and by measuring residual bound 125I-TSH after addition of IgG. TBIA was evaluated by determining binding of 125I-TSH to thyroid plasma membranes preincubated with IgG. Results were expressed as % TSH-displacing or binding inhibition activities of test IgG with respect to normal control IgG. The percent of TDA positive Graves' IgG preparations (72.7%) was greater than that of TBIA positive (48.5%). There was no correlation between TDA and TBIA results, since 11 Graves' IgG preparations were TDA positive but TBIA negative, and 6 were TDA negative but TBIA positive. Hashimoto's or idiopathic myxedema IgG preparations were positive in 2/7 in the TDA and in 1/7 in the TBIA assays, respectively. Neither TDA nor TBIA correlated with TSAb determined by cAMP accumulation in thyroid plasma membrane. The TDA assay developed in this study appeared to be more sensitive than the more widely used TBIA assay.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies↗
PubMed1982

Thyroid-stimulating immunoglobulins.

The presence of thyroid-stimulating immunoglobulins in patients with Graves' disease is well established. Considerable evidence has accumulated that these immunoglobulins are antibodies to a thyroid plasma membrane antigen whose precise nature remains to be identified. The question whether the antigen is related to the TSH receptor is still debated. The causative role of thyroid-stimulating immunoglobulins in the hyperthyroidism of Graves' disease is widely recognized. The use of human specific stimulation assays has circumvented the objection of the relatively low frequency of long-acting-thyroid-stimulator-(LATS)-positive patients. Individual variations in the thyroid response may account for the lack of correlation between the levels of thyroid-stimulating immunoglobulins and most parameters of thyroid function. In this respect, the interference of nonstimulatory thyroid antibodies and of other autoimmune mechanisms may be of importance. An important clinical implication of thyroid-stimulating immunoglobulin determinations is their value in predicting the relapse of hyperthyroidism in treated patients. This clinical application has been so far limited by the technical difficulties of the assays. This emphasizes the need for a simple and reliable test, which can be used for routine measurements of thyroid-stimulating immunoglobulins.

Graves Disease↗
PubMed1982

[Thyroid-stimulating immunoglobulins. The related antigens].

The presence of thyroid stimulating antibodies (TSAb) in patients with Graves' disease is well established. Considerable evidence has accumulated that these are antibodies to thyroid plasma membrane components related to the TSH receptor. The question of whether thyroid stimulation is mediated by a direct interaction with the TSH binding site is still debated. Recent data obtained by the use of monoclonal antibodies to the TSH receptor are consistent with the view that Graves' immunoglobulins comprise antibodies to at least two different components of the TSH receptor complex, one of which is more strictly related to the binding of TSH and the other to the transmission of the hormonal effect. The causative role of TSAb in the hyperthyroidism of Graves' disease is widely recognized. The use of human specific stimulation assays has circumvented the objection of the relatively low frequency of LATS-positive patients. Individual variations in the thyroid response may account for the lack of correlation between levels of thyroid stimulating immunoglobulins and most parameters of thyroid function. In this respect, the interference of non-stimulatory thyroid antibody and of other autoimmune mechanisms may be of importance. An important clinical implication of TSAb and TSH-binding inhibiting antibody determinations is their prognostic value in predicting the relapse of hyperthyroidism in treated patients. This clinical application has been so far limited by the technical difficulty of the assays. This emphasizes the need for a simple and reliable test, which can be used for routine measurements of TSAb.

Antibodies, Monoclonal↗
PubMed1981

Comparison between thyroid stimulating and tsh-binding inhibiting immunoglobulins of Graves' disease.

In the sera of patients with Graves' disease abnormal thyroid 'stimulating' immunoglobulins have been demonstrated by in vivo and in vitro assay systems. Conflicting results have been reported when thyroid stimulating and thyrotrophin (TSH)-binding inhibiting activities have been compared. The present study was performed in forty-nine hyperthyroid Graves' patients to ascertain the relationships among TsH-binding inhibiting immunoglobulins (TBII), measured by a radio-receptor assay, thyroid stimulating antibody(TSAb), assayed by stimulation of adenylate cyclase-cAMP system in human thyroid plasma membranes, and LATS, measured by McKenzie's mouse bioassay.TBII was detected in twenty-one of forty-nine (42.9%), TSAb in thirty-five of forty-nine (71.4%) and LATS in nineteen of forty-nine (38.8%).TBII was also present in four of sixteen (25%) patients with other thyroid autoimmune disorders. When the results obtained with the different techniques were compared, correlation was found between LATS response and TSAb activity ( =0.53, P less than 0.001), while there was no correlation between TSAb and TBII activities and between LATS response and TBII activity. These data conform that TSAb is specific and sensitive marker of Graves' disease and suggest that TBII activity is not necessarily synonymous with thyroid stimulation, and could reflect a different phenomenon concomitantly produced.

Animals↗
PubMedDate not supplied

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).

Adolescent↗
PubMedDate not supplied

Percutaneous ethanol injection treatment of autonomously functioning single thyroid nodules: optimization of treatment and short term outcome.

Twenty-five patients with solitary autonomous thyroid nodules (15 nontoxic, 10 toxic) received percutaneous ethanol injection treatment (PEIT) under sonographic guidance in 4-7 sessions (1-2 weekly). To test different doses, smaller nodules (volume less than 15 mL) were given 0.75-2.8 mL ethanol/mL nodular tissue while larger nodules received 0.5-1 mL/mL. Except for 1 patient who developed hyperpyrexia, no relevant adverse effects were observed. A slight, asymptomatic increase in serum thyroid hormone levels was observed in both groups during the treatment. Three months after treatment, a biochemical and clinical remission of hyperthyroidism was observed in 8 of 10 patients with toxic nodules. A significant increase of TSH level was seen in both groups (p less than 0.01). Significant shrinkage of volume (p less than 0.001) as well as structural alterations of nodules were consistently recorded at sonography. A linear relationship (r = 0.98; p less than 0.0001) between pretreatment volume and volume reduction was found both for large and small nodules, thus suggesting that even limited ethanol doses may be therapeutically effective. A recovery of extranodular parenchyma activity at scintiscan occurred in 16 (64%) of 25 patients. These data confirm that PEIT is effective in obtaining functional ablation and in inducing remission of hyperthyroidism. Adverse effects are infrequent. In spite of the small patient sample, a 0.5-1 mL ethanol dose per each mL of tissue appears as effective as larger doses and seems appropriate for treatment.

Drug Evaluation↗
PubMedDate not supplied

[Preclinical hypothyroidism: early involvement of memory function, behavioral responsiveness and myocardial contractility].

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.

Adult↗
PubMedDate not supplied

Familial occurrence of hypothyroidism and cerebellar ataxia.

Several cases of association between cerebellar ataxia and hypothyroidism have been reported, in which cerebellar symptoms regressed after euthyroid state was obtained, suggesting an etiologic relationship between hypothyroidism and ataxia. We present a further case of hypothyroidism and ataxia, with a peculiar positive family history for both thyroid and cerebellar disorders. Long-term replacement therapy with L-thyroxine determined the regression of hypothyroidism; however, no improvement in cerebellar symptoms was observed. The lack of response of the neurologic symptoms to L-thyroxine treatment suggests the absence of an etiological relationship between thyroid disease and cerebellar disease in this case.

Adult↗
PubMedDate not supplied

[Postoperative organotherapy for multinodular goiter].

Post-operative therapy with L-Tiroxine can have a suppressive or substitutional aim. After a total thyroidectomy the patients need a substitutional therapy, while after subtotal thyroidectomy the aim of the therapy is to suppress the TSH secretion. In the second case we want either to avoid the recurrence, either to give the hormones that residual gland cannot produce. The drug of choice is L-Tiroxine for both suppressive o substitutional therapy: There is a difference in dosage, that must be greater in first case. While there are some doubts in the literature on the success of the suppressive therapy, we believe that there is enough evidence of his utility.

Goiter, Nodular↗