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Biomedical subjects

C Marcocci

Publications and source records attributed to C Marcocci.

At least 109 records · Page 6Linked to original sources
PubMed1987

Role of the adenylate cyclase-cAMP system on TSH-stimulated thyroid cell growth.

TSH is a trophic factor for cultured rat thyroid cells (FRTL-5). In the present study we have investigated the mechanism by which TSH promotes cell growth and evaluated the possible role of the adenylate cyclase (AC)-cAMP system in this process. The mitogenic activity of several agents was evaluated by measuring their effect on cell number or 3H-thymidine incorporation into DNA. Forskolin and cholera toxin, two potent and specific activators of the AC, induced a dose dependent increase of 3H-thymidine incorporation. The maximal stimulation, observed at concentrations of 10 microM and 10 ng/ml, respectively, was beta 80% of that obtained with optimal concentrations of TSH. A similar effect was obtained with a Graves' IgG preparation (0.2 mg/ml) able to stimulate the thyroid AC or with 3-isobutyl-1-methyl-xanthine (IBMX, 0.5 mM), a phosphodiesterase inhibitor. 8-bromo cAMP (0.5 mM), a cAMP analog, also stimulated 3H-thymidine incorporation, and its potency was approximately 60% of that of TSH. Similar results were obtained when the mitogenic activity of these compounds was evaluated by cell number. Norepinephrine (NE, 10 microM), although devoid of AC stimulatory activity in these cells, also stimulated 3H-thymidine incorporation, but its potency was only 20-30% of that of TSH. Indomethacin (100 microM), an inhibitor of phospholipid and arachidonic acid metabolism, was able to inhibit the stimulatory effect of NE (84%), and to a lesser extent of TSH (63%) and cholera toxin, had minor effect on forskolin (24%), IBMX (16%) and Graves' IgG (8%), and no effect on 8-bromo cAMP.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗
PubMed1986

L-thyroxine therapy induces a fall of thyroid microsomal and thyroglobulin antibodies in idiopathic myxedema and in hypothyroid, but not in euthyroid Hashimoto's thyroiditis.

Thyroid microsomal (MAb) and thyroglobulin (TgAb) antibodies were sequentially measured by sensitive and quantitative radioassays in 17 patients with goitrous Hashimoto's thyroiditis (9 hypothyroid, 8 euthyroid) and in 19 patients with idiopathic myxedema before and at various time intervals up to 24-48 months after the institution of L-thyroxine therapy. Thyroid antibodies were also determined in 5 euthyroid subjects with Hashimoto's thyroiditis maintained without treatment for a similar period. During L-thyroxine administration a reduction of MAb with respect to the pretreatment level was found in 6 of the 9 (67%) hypothyroid patients with Hashimoto's thyroiditis and in 16 of the 19 (84%) patients with idiopathic myxedema. The decrease of MAb was highly significant in both groups (p less than 0.001 and p less than 0.0001, respectively). A fall of TgAb occurred in 2 of the 3 patients (75%) with hypothyroid Hashimoto's thyroiditis and in 9 of the 10 (90%, p less than 0.001) patients with idiopathic myxedema having abnormally elevated pretreatment TgAB levels. No consistent pattern of MAb and TgAb changes was observed in the euthyroid subjects with Hashimoto's thyroiditis, whether treated or untreated. In the hypothyroid patients with Hashimoto's thyroiditis a significant association was found between the decrease of MAb and the reduction of goiter size (p less than 0.05) occurring during L-thyroxine administration. Moreover, the decrease of MAb and TgAb in idiopathic myxedema was greater (p less than 0.05) in the patients with normalized serum TSH (less than or equal to 4 microU/ml) than in those showing only a partial reduction of serum TSH (greater than 4 microU/ml) under L-thyroxine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Monoclonal antibody studies defining the origin and properties of autoantibodies in Graves' disease.

The present report summarizes experiments with monoclonal antibodies to the TSH receptor. The data provide further insight into the TSH receptor structure and into the basis of autoimmune antibodies implicated in the pathogenesis of Graves' disease. They resolve many clinical questions and provide new approaches to enhance our understanding of autoimmune disease. In one new approach, it has been noted that the 11E8 TBIAb can precipitate the phosphorylated beta subunit of the insulin and IGF1 receptor. This cross-reactivity or recognition of determinants adjacent to the TSH receptor may not be random. Insulin, IGF1, alpha 1 adrenergic, and TSH receptors have been linked to a synergistic cascade response system of the thyroid involving growth, thyroglobulin biosynthesis, iodination of thyroglobulin, and thyroid hormone formation. Future studies with the monoclonals may help unravel this cascade system and its regulatory relationships, along with the relationships between autoimmune thyroid disease and autoimmune diseases of other organs.

Antibodies, Anti-Idiotypic↗
PubMed1985

Association of the changes in cytosolic Ca2+ and iodide efflux induced by thyrotropin and by the stimulation of alpha 1-adrenergic receptors in cultured rat thyroid cells.

Thyrotropin causes a time- and concentration-dependent increase in cytosolic Ca2+ in FRTL-5 rat thyroid cells as measured by Quin2 fluorescence; the half-maximal response occurs in response to 1 X 10(-7) M thyrotropin. The effect of added thyrotropin is the same whether cells have been previously and chronically exposed to thyrotropin or whether they have been thyrotropin "starved" for several days. The thyrotropin effect on cytosolic Ca2+ has no relationship to intracellular cAMP levels with respect to dose and time course. Norepinephrine (1 X 10(-7) M) also causes increases in cytosolic Ca2+ in FRTL-5 thyroid cells. With the use of a variety of adrenergic inhibitors, norepinephrine was found to exert its effect via an alpha 1-adrenergic receptor. The exposure of FRTL-5 cells to physiological thyrotropin concentrations enhances the effect on cytosolic Ca2+ level induced by norepinephrine in vitro; the shape of the dose-response curve indicates a cooperative effect of the thyrotropin and norepinephrine. The increase in cytosolic Ca2+ seems to be derived from an intracellular pool rather than from the extracellular space. It is not prevented by nifedipine, a blocker of Ca2+ channels; it is present in cells exposed to ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid; and it is not associated with increased Ca2+ uptake into the cell. the thyrotropin- and norepinephrine-induced increase in cytosolic Ca2+ parallels the efflux of iodide and the organification of thyroglobulin in a dose-dependent manner.

Adrenergic alpha-Antagonists↗
PubMed1984

Cutaneous metastasis of a radiation-associated thyroid medullary carcinoma.

The rare event of a single cutaneous metastasis occurred in a 37-year-old white man two years after a subtotal thyroidectomy for sporadic medullary carcinoma is reported. The endocrine nature of the tumor is revealed by the ultrastructural study, and the type of secretion by the biochemical assay of calcitonin (CT) in the serum and in the tumor tissue extract and by the PAP (peroxidase-anti-peroxidase) technique with anti-CT antibodies on paraffin sections. The cytological and histological findings are described. Some peculiar ultrastructural aspects are presented in details. The fact that the patient received a course of Rx therapy (3,000 rads) on the neck for cervical syringomyelia at the age of 20 years is stressed.

Adult↗
PubMed1984

Effect of actinomycin D on iodide transport in FRTL-5 thyroid cells.

TSH-induced I- uptake in FRTL-5 thyroid cells requires new protein synthesis. During the induction of I- uptake, which takes nearly 60 h to reach its maximum, two waves of protein synthesis can be identified: one during the first 8 h and another after 24-30 h, each involving different proteins. Cycloheximide (CH) added during the first 10 h of a 48-h incubation with TSH completely inhibits the induction of I- uptake; 58% inhibition is observed with CH added at 24 h; no inhibition is observed when CH is added 36 h after TSH. Like CH, actinomycin D (ActD), added at the beginning of the 48-h period, inhibits TSH induction of I- uptake; partial inhibition (83%, 72%, and 28%) is observed when ActD is added at 1, 5, and 10 h, respectively. Treatment with ActD at 24 h (ActD-treated cells), however, paradoxically increases I- uptake (1.8- to 3.5-fold over the control value). The characteristics of I- uptake in ActD-treated cells are the same as those in untreated cells; both are Na+ dependent and can be inhibited in a comparable manner by anions. Kinetic measurements of I- transport indicate that ActD increases the rate of I- influx (2-fold or greater increase in maximum velocity without a significant change in Km), with only minor changes in I- release. Enhanced I- uptake in ActD-treated cells is inhibited by the simultaneous (24-h) administration of CH, indicating that protein synthesis is required for the late ActD effect. Despite an overall 2-fold decrease in protein synthesis in cells treated with ActD at 24 h, the synthesis of individual proteins maximally induced by TSH during the first 8 h is increased, whereas that of some proteins maximally synthesized after 24-30 h is markedly reduced. The present data indicate that TSH-induced I- uptake in FRTL-5 cells involves a regulatory action of TSH that operates at the mRNA level.

Animals↗
PubMed1984

Measurement of 1,25-dihydroxyvitamin D3 receptors in breast cancer and their relationship to biochemical and clinical indices.

Both normal and malignant breast tissue contain the specific receptor for 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3). A recent study has shown its presence in 80% of surgically removed breast tumors, although only at low levels. We have measured the 1,25-(OH)2D3 receptor in breast tumors from 68 patients and have found it at similar frequency (75%) but at much higher concentrations (range, less than 1 to 30 fmol/mg protein). This receptor has the same characteristics as that measured in classic 1,25-(OH)2D3 target tissues and was distinguished by sucrose gradient centrifugation from plasma contaminants. Complete case histories and follow-up were available on 56 of these patients, and 1,25-(OH)2D3 receptor status (less than 8 or greater than or equal to 8 fmol/mg protein) was not related to the level of estrogen receptors, menopausal status, T-stage or histology of tumors, or presence of 99mTc phosphate hot spots on bone scans. The lack of relationship between the level of 1,25-(OH)2D3 receptors and other prognostic indicators suggests its potential as a new independent variable for assessing breast cancer patients. However, at this stage, 1,25-(OH)2D3 receptor status did not result in any significant difference in probability of survival or metastasis-free survival. Assessment of the importance of this variable for treatment or outcome must await an increased number of patients and a longer time since surgery.

Breast Neoplasms↗
PubMed1983

Graves' IgG stimulation of iodide uptake in FRTL-5 rat thyroid cells: a clinical assay complementing FRTL-5 assays measuring adenylate cyclase and growth-stimulating antibodies in autoimmune thyroid disease.

With optimal conditions and cells maintained in the absence of thyrotropin (TSH) for 7-10 days, IgG preparations from approximately 90% of patients with active Graves' disease can exhibit statistically significant stimulation of cAMP levels in rat FRTL-5 thyroid cells as compared to normal controls. FRTL-5 cells maintained in the absence of TSH for 7-10 days lose their ability to take up iodide. Iodide uptake returns upon readdition of TSH over a 60-hour period via a cAMP-mediated process; thus TSH can be replaced by dibutyryl cAMP or other agents which increase cAMP levels, for example, thyroid-stimulating autoantibodies (TSAbs) from Graves' sera. TSAb stimulation of iodide uptake requires the continued presence of TSAb over at least the first 24 hours of a 48-hour reversal period; TSH, in contrast, can be withdrawn after 5 hours and will still achieve maximal effects at 36-48 hours. Iodide uptake, measured as a 30-minute pulse at 48 hours, appears, however, to be faster with TSAb than TSH. With optimized conditions (cells depleted of TSH greater than 7-10 days; 3-isobytyl-1-methyl xanthine, 0.005 mM; TSAb addition for the entire 48-hour assay period; and a 30-minute pulse of 10 microM 125I-sodium iodide at 37 C), TSAb stimulation is concentration-dependent with a half-maximal activity at approximately 10-fold lower concentrations than in the cAMP stimulation assay. In a series of 24 patients with Graves' disease, IgGs with positive values in the cAMP assay were positive in the iodide uptake assay.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗
PubMed1983

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.

Adolescent↗
PubMed1982

Studies on thyroid cell surface antigens using cultured human thyroid cells.

Human thyroid cells in primary culture were used for studies of thyroid cell surface antibodies in patients with thyroid autoimmune disorders. Radioiodinated IgG preparations containing thyroid microsomal antibody (TMAb), thyroid stimulating antibody (TSAb) and/or thyroglobulin antibody (TgAb) were tested for binding to thyroid cells. Binding was observed with radioiodinated IgG from patients with Graves' disease, Hashimoto's thyroiditis and idiopathic myxoedema containing TMAb, irrespective of the presence of TSAb and TgAb, while negative results were obtained with normal IgG. A dose-dependent inhibition of binding to thyroid cells was produced by the addition of the corresponding unlabelled IgG preparations. Evidence for tissue specificity was provided by the absence of binding to human skin fibroblasts used as controls. Preabsorption with human thyroid microsomes completely abolished the binding to thyroid cells of a radioiodinated TMAb positive IgG preparation, while only incomplete removal of the reactivity to thyroid microsomes was produced by preabsorption with thyroid cells. These data suggest that some but not all microsomal antigenic determinants are expressed on the thyroid cell surface. Binding to thyroid cells was also observed with purified TgAb, indicating that thyroglobulin antigenic determinants are present on the surface of thyroid cells. No evidence of binding was obtained with a TSAb positive Graves' IgG preparation with undetectable TMAb and TgAb. Unlabelled IgG preparations containing TMAb from patients with either Hashimoto's thyroiditis or idiopathic myxoedema were shown to inhibit the binding to thyroid cells of radioiodinated TMAb positive Graves' IgG and vice versa. These data indicate that antibodies present in these thyroid autoimmune disorders share common thyroid cell surface antigens. However, the binding of radioiodinated IgG from a patient with idiopathic myxoedema was only partially inhibited by Graves' or Hashimoto's IgG, suggesting that some of the thyroid cell surface antibodies of idiopathic myxoedema may not be detectable in other thyroid autoimmune disorders.

Antibodies↗
PubMed1979

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.

Antigens↗
PubMed1978

Comparison of radioassay and haemagglutination methods for anti-thyroid microsomal antibodies.

Parallel measurements of circulating anti-thyroid microsomal (anti-M) antibodies by radioassay and haemagglutination were performed on subjects with or without thyroid disorders. Three-quarters (75.4%) of control subjects had undetectable antibody levels (less than 10 u/ml) by radioassay and only 3.1% had concentrations of greater than or equal to 75 u/ml. Abnormally elevated levels (greater than or equal to 75 u/ml) were found in most of the patients with Hashimoto's thyroiditis (94.1%) or idiopathic myxoedema (86.7%), in the majority (75.0%) of those with Graves' disease and only in a minority of those with other thyroid disorders. The percentage of positive sera by haemagglutination was very similar in all groups to that of abnormal values observed in the radioassay. Direct comparison of parallel tests on a total of 631 sera revealed a highly significant correlation (r = 0.91, P less than 0.001) between the two methods, but elevated antibody titres by haemagglutination were found in some sera with negative radioassays. All these sera were from a single patient with thyroid carcinoma associated with Hashimoto's thyroiditis and had elevated levels of anti-thyroglobulin (anti-Tg) antibodies. Evidence that such discrepancies were due to anti-Tg antibodies reacting with microsomal-bound Tg was provided by the demonstration that the haemagglutination produced by these sera could be completely inhibited by the addition of Tg. A similar inhibition was observed with two rabbit antisera to human Tg, but not with sera from patients with thyroid autoimmune disorders containing high levels of anti-microsomal anti-bodies.

Adenoma↗
PubMedDate not supplied

Calcium-sensing receptor gene polymorphisms in primary hyperparathyroidism.

The calcium-sensing receptor (CaR) polymorphism A986S has been found to be associated with higher serum calcium levels in normal subjects, suggesting that this amino acid change might decrease the inhibitory activity of the mutated receptor, render the parathyroid cells more prone to proliferate, and eventually increase the risk of developing primary hyperparathyroidism (PHPT). The aim of the present study was to investigate the frequency of this and other 2 known CaR polymorphisms (R990G and Q1011 E) in patients with PHPT and their effect on its phenotype. We studied 103 Italian patients with PHPT and 148 healthy Italian subjects and we compared the results in 50 pairs matched for sex, age and geographic provenience. A fragment of exon 7 of the CaR gene, containing the 3 polymorphic loci of interest (A986S, R990G, and Q1011E), was amplified by PCR and sequenced. Serum calcium and PTH levels, BMD and other biochemical and clinical parameters were evaluated. The frequency distribution of the A9865, R990G, and Q1011 E polymorphisms in the 103 PHPT patients was 39.8%, 5.8%, and 2.0%, respectively. There was no difference in the frequency of the 3 CaR polymorphisms in the 50 matched pairs of patients and controls. We found no significant difference in several clinical and biochemical parameters between PHPT patients carrying or not the 986S allele. Finally, no relationship was observed between the 986S genotype and total and ionized serum calcium in control subjects. The A986S CaR polymorphism is the most common in Italian PHPT patients and the allotype AS does not appear to play a relevant role in the pathogenesis of PHPT and its severity. The A986S polymorphism does not correlate with serum calcium levels in normal Italian subjects.

Adult↗