Mutations in the SLC26A4 (pendrin) gene in patients with sensorineural deafness and enlarged vestibular aqueduct

Pendred syndrome and the enlarged vestibular aqueduct (EVA) are considered phenotypic variations of the same entity due to mutations in the SLC26A4 (pendrin) gene. Pendred syndrome consists in sensorineural deafness, goiter and impaired thyroid hormone synthesis while in EVA thyroid function seems to be preserved. The aim of this study was to evaluate thyroid function and morphology and to look for mutations in the SLC26A4 gene in patients presented with EVA. Among 57 consecutive patients with sensorineural deafness 15 with EVA, as assessed by magnetic resonance imaging (MRI), were identified and studied. A complete evaluation of thyroid function including thyroid echography and perchlorate discharge test was carried out in all patients with EVA; all exons of the SLC26A4 gene were amplified from peripheral leukocytes and directly sequenced, using specific intronic primers. Out of 15 patients with EVA, goiter was present in 8 (53%), hypothyroidism in 7 (47%), increased serum thyroglobulin levels in 8 (53%) and a positive perchlorate discharge test in 10 (67%). Nine alleles of the SLC26A4 gene were mutated: 2 novel mutations (L465W and G497R) and 4 already known mutations (T410M, R409H, T505N and IVS1001+1G>A) were found. Four subjects were compound heterozygous and 1 heterozygous (G497R/wt). All patients harbouring mutations in the SLC26A4 gene had goiter and a positive perchlorate discharge test: 3 were slightly hypothyroid and 2 euthyroid. The remaining 10 patients had no mutations in the SLC26A4 gene: 4 of them were hypothyroid, 2 with goiter and positive perchlorate discharge test, 2 without goiter and with negative perchlorate discharge test. Two patients without mutations were euthyroid with positive perchlorate discharge test. Patients with mutations in the SLC26A4 gene had larger thyroid volume (p<0.002), higher serum thyroglobulin (Tg) levels (p<0.002) and greater radioiodine discharge after perchlorate (p=0.09) than patients without mutations. The results of the present study lend support to the concept that all patients with mutated SLC26A4 gene have abnormalities of thyroid function tests.

Improvement of growth hormone deficiency in patients with primary hyperparathyroidism after parathyroidectomy: results of a prospective study

GH secretion is impaired in most patients with primary hyperparathyroidism (PHP), although the secretion of the other anterior pituitary hormones is unaffected. However, whether restoration of euparathyroidism is associated with reversal of GH deficiency in PHP patients is not known. To address this issue, we studied 30 consecutive patients with PHP due to a single parathyroid adenoma before and after parathyroidectomy. GH secretion was evaluated by peak serum GH after the maximal GHRH + arginine (Arg) stimulation test. A group of 35 age- and sex-matched normal subjects served as controls. Serum IGF-I concentration was below the normal age- corrected values in six of 30 patients before surgery and in four of 30 patients after parathyroidectomy (P = not significant). Mean serum peak GH values after the GHRH + Arg test were 17.5 +/- 2.8 micro g/liter before surgery and 23.8 +/- 2.5 micro g /liter after surgery (P = 0.0008). The GH response to the GHRH + Arg test was reduced in 20 (67%) and normal in 10 (33%) of 30 PHP patients at baseline; after surgery, 22 of 30 (73%) PHP patients had a normal GH response to the GHRH + Arg test, and only eight (27%) had an impaired GH secretion (P < 0.02). In conclusion, this study confirms that GH secretion is impaired in PHP patients and indicates that it is reversed in many patients after parathyroidectomy. Accordingly, GH deficiency in PHP patients must be considered a functional phenomenon for which GH therapy is not recommended.

Molecular mechanisms for pituitary thyrotroph cell growth

Neuroendocrine, endocrine and autocrine/paracrine signals contribute to the regulation of basal thyrotroph growth. Thyrotropin-releasing hormone (TRH), somatostatin, thyroid hormone (TH), estrogens (Es) and epidermal growth factor, all may play a role both in normal and tumoral thyrotroph proliferation, acting via either plasma membrane receptors and non-genomic steps or nuclear receptors and gene transcription. Signaling features common to all these ligands are involvement of G protein-coupled receptors, mitogen-activated protein kinase cascade and nuclear polyphosphoinositide cycle. In addition, each growth information, independently from the eliciting factor, may be routed intracellularly following a branched pathway, that often links different transduction systems at common check-points, as the Shc-Grb2-SOS complex. Finally, some ligands (e.g. TRH, TH, Es) may display opposite effects on thyrotroph growth, depending on environmental conditions and state of cell differentiation. These ambiguities of response can be interpreted using a "fuzzy" logic-based model of intracellular signaling. Accordingly, check-points common to different transduction cascades may be envisaged as targets for antitumoral therapy selective to the neoplastic thyrotroph cell.

Impaired GH secretion to provocative stimuli in two families with hypocalciuric hypercalcaemia

OBJECTIVE

To determine whether hypercalcemia per se might be responsible for an impairment in GH secretion.

DESIGN

Prospective study.

PATIENTS

Six subjects of two unrelated families with familial hypocalciuric hypercalcaemia (FHH), an autosomal dominant disorder due to inactivating mutations in the calcium receptor gene, leading to an increase in serum calcium levels and inappropriately normal serum PTH concentrations. Forty normal subjects, matched for sex and age served as controls.

MEASUREMENTS

Serum GH concentrations were measured after GHRH-Arginine (GHRH-Arg) stimulation test; serum IGF-I, ACTH, cortisol, FT4, FT3, TSH, PRL, LH, FSH levels were measured under basal conditions.

RESULTS

All subjects (two male, four female, age range 24-74 years) had increased serum ionized calcium levels (range 1.36-1.56 mmol/l) and five of six patients had normal PTH levels (range for all patients was 14-68 ng/l). Basal serum GH concentrations ranged from 0.1 to 7.0 micro g/l. Mean serum GH secretory peak after GHRH-Arg stimulation test was reduced in five subjects (mean 9.3 +/- 3.6 microg/l, P < 0.006 vs. Controls, mean 67.0 +/- 44.0 microg/l, cut-off, 16.0 microg/l) and normal in one subject (38.7 microg/l). However, serum IGF-I levels were reduced only in two patients (29 and 57 microg/l) and normal in four subjects (range 127-208 microg/l). The basal secretion of the other anterior pituitary hormones was within their normal ranges.

CONCLUSIONS

The results of the present study support the concept that elevated serum calcium levels impair GH secretion. However, the clinical relevance of GH deficiency in FHH remains to be elucidated.

Colonic polyps of acromegalic patients are not associated with mutations of the peroxisome proliferator activated receptor gamma gene

Peroxisome proliferator activated receptor (PPAR)gamma plays a pivotal role in regulating adipocyte differentiation and metabolism, but also has an antiproliferative effect in several tissues, including colonic mucosa, where it is highly expressed. Loss-of-function mutations have been reported in about 10% of sporadic primary colon cancer. Acromegalic patients have an increased prevalence of colonic neoplasms and lower PPARgamma levels in the colonic mucosa. Thus, PPARgamma may act as a tumor suppressor gene, and its reduced expression or loss-of-function mutations may contribute to tumorigenesis. In this study the expression and mutations of the PPARgamma gene in the colonic polyps and mucosa outside polyps were investigated in 10 acromegalic and 17 non-acromegalic patients. PPARgamma expression was evaluated by RT-PCR. PPARgamma was expressed in each sample, but expression appeared to be lower in polyps than in mucosa outside polyps from either acromegalic or non-acromegalic patients. All exons of the PPARgamma gene were directly sequenced after PCR amplification: no mutations were found either in acromegalic or in non-acromegalic patients. In conclusion, the results of this preliminary study suggest that the lower expression of PPARgamma rather than somatic mutations of this gene is involved in colonic tumorigenesis.

Effects of a mixture of polychlorinated biphenyls (Aroclor 1254) on the transcriptional activity of thyroid hormone receptor

Polychlorinated biphenyls (PCBs) are environmental contaminants which may affect thyroid function. PCBs may reduce serum thyroid hormone (TH) concentrations by either displacing T4 from TH transport proteins or increasing its hepatic metabolism. The reduced serum T4 causes neurological and growth defects in animals exposed to PCBs during the perinatal period, which can partially be reverted by T4 administration. In addition to a hypothyroid-like syndrome, a direct action of PCBs on TH-sensitive genes has been postulated. In the present study the effects of Aroclor 1254 (ARO), a mixture of PCBs, on transcription of TH-dependent genes were investigated. A reporter plasmid containing the TH-responsive element (TRE) of malic enzyme (ME) gene was used in transient transfections to assess the responsiveness to ARO. ARO (10 microM) reduced the CAT activity by about 50% and competed with T3 to reduce the induction of transcription. Cotransfection of TH receptor (TR) and a wild type TRE was required to reveal ARO inhibitiry effect, which was abolished by a mock reaction not containing TR or by a mutated TRE. ARO reduced the 125I-T3 binding to TR by 30%, but did not affect the interaction of TR with a 32P-labeled TRE in gel shift assay. ARO is likely to produce a conformational change in in vitro translated TR, leading to its increased proteolysis by trypsin. These results demonstrate that ARO interacts with TR, thereby affecting the transcription of TH-sensitive genes, and provide a molecular basis to further explain the complex effects of PCBs on TH disruption.

TSH receptor and Gs(alpha) genetic analysis in children with Down's syndrome and subclinical hypothyroidism

The prevalence of thyroid diseases in children with Down's syndrome (DS) is about 3%. The most frequently observed condition is autoimmune subclinical hypothyroidism (SH). Autoimmune SH must be distinguished from defects in the biological activity of the TSH molecule or from the rare inherited condition of thyroid resistance to TSH. To investigate this last aspect we studied 12 patients with DS that had moderately elevated TSH with normal free thyroid hormones without signs of autoimmunity. For the genetic analysis the genomic DNA was extracted from peripheral lymphocytes. All the exons of the TSH receptor (TSHr) and Gs(alpha) genes were sequenced. The genetic analysis of the TSHr gene revealed the presence of four polymorphic variants. In two patients there was an allelic variant in the exon 1 (Pro52Thr--in one patient in the heterozygous state and in the other as a homozygous substitution). In one patient there was an allelic variant in the exon 1 (Asp36His) in the heterozygous state. In 11 patients there was a silent polymorphism in the exon 7 at nucleotide 561. All patients were homozygous for a silent polymorphism in the exon 9 at nucleotide 855. No inactivating mutations of TSHr or Gs(alpha) genes were identified in the 12 patients. In conclusion, our results seem to exclude the role of TSHr or Gs(alpha) gene mutations in the pathogenesis of the non-autoimmune SH observed in some children with DS.

Changes in the expression of the peroxisome proliferator-activated receptor gamma gene in the colonic polyps and colonic mucosa of acromegalic patients

Acromegalic patients have an increased prevalence of colonic neoplasms and lower peroxisome proliferator-activated receptor gamma (PPARgamma) levels, the latter acting as a tumor suppressor gene. In this study we evaluated the expression of PPARgamma in the biopsy samples of the polyps and outside polyps colonic mucosa from seven patients with active, untreated acromegaly, 11 with cured disease, and 15 controls. Serum GH and IGF-I levels were higher in patients with untreated acromegaly than in those with acromegaly in remission or controls (P = 0.003 and P = 0.002, respectively) The expression of PPARgamma mRNA (mean +/- SE) was 1) mucosa outside polyps, 24,188 +/- 3,254 transcripts in the controls, 22,432 +/- 2,006 transcripts in acromegaly in remission, and 1,952 +/- 342 transcripts in untreated acromegaly (P < 0.0001 vs. controls and acromegaly in remission); and 2) polyps mucosa, 1,554 +/- 236 transcripts in the controls, 1,112 +/- 143 in acromegaly in remission, and 1,570 +/- 251 in untreated acromegaly (P = NS among polyps groups and mucosa outside polyps of untreated acromegaly; P < 0.0001 vs. mucosa outside polyps of controls and acromegaly in remission). Eighty-five percent of the cells in the mucosa outside polyps from controls or acromegaly in remission were positive at immunohistochemistry, at variance with 45% of the cells from polyps mucosa from each group and from those of mucosa outside polyps of untreated acromegaly (P = 0.0002). In conclusion, patients with untreated acromegaly have reduced expression of PPARgamma in the mucosa outside polyps, which might be reversed by curing the disease; conversely, patients with acromegaly in remission have the same low levels of expression of PPARgamma in the polyps mucosa as untreated acromegaly or controls, supporting the concept that reduced expression of PPARgamma might be an early event in colonic tumorigenesis.

Zinc ions alter morphology and chitin deposition in an ericoid fungus

A sterile mycelium PS IV, an ascomycete capable of establishing ericoid mycorrhizas, was used to investigate how zinc ions affect the cellular mechanisms of fungal growth. A significant reduction of the fungal biomass was observed in the presence of millimolar zinc concentrations; this mirrored conspicuous changes in hyphal morphology which led to apical swellings and increased branching in the subapical parts. Specific probes for fluorescence and electron microscopy localised chitin, the main cell wall polysaccharide, on the inner part of the fungal wall and on septa in control specimens. In Zn-treated mycelium, hyphal walls were thicker and a more intense chitin labelling was detected on the transverse walls. A quantitative assay showed a significant increase in the amount of chitin in metal-treated hyphae.

The prevalence of elevated serum C-reactive protein levels in inflammatory and noninflammatory thyroid disease

C-reactive protein (CRP) levels have not been routinely used to diagnose thyroid disease, although many thyroid conditions involve inflammation. This study was intended to determine whether CRP levels could differentiate between inflammatory and noninflammatory thyroid conditions, especially between type II inflammatory amiodarone-induced thyrotoxicosis (AIT) and type I iodine-induced AIT. Serum high-sensitivity CRP levels were measured in 100 euthyroid controls (7 taking amiodarone) and 353 patients with one of the following thyroid conditions: AIT, subacute thyroiditis, toxic diffuse goiter, nodular goiter, Hashimoto's thyroiditis, shortterm hypothyroidism, or postpartum thyroiditis. No patients with nontoxic multinodular goiter (n = 34), toxic nodular goiter (n = 23), or toxic diffuse goiter, either untreated (n = 49) or euthyroid while taking methimazole (n = 33), had positive CRP levels (>10 mg/L). The occurrence of positive CRP levels among patients with Hashimoto's thyroiditis (n = 35), short-term hypothyroidism (n = 38), and postpartum thyroiditis (n = 70) did not differ significantly from controls. The occurrence of positive CRP values did not differ significantly between patients with type I and type II AIT and controls. Six of 7 patients (86%) with untreated subacute thyroiditis had positive CRP levels (p < 0.00001). These results indicate that there is only a limited role for measurement of CRP levels in the diagnosis of thyroid diseases other than subacute thyroiditis.

Thyroid color flow doppler sonography and radioiodine uptake in 55 consecutive patients with amiodarone-induced thyrotoxicosis

Amiodarone-induced thyrotoxicosis (AMT) is a life-threatening condition, the appropriate management of which is achieved by identifying its different subtypes. Type 1 AIT develops in patients with underlying thyroid abnormalities and is believed to be due to increased thyroid hormone synthesis and release; Type 2 AIT occurs in patients with a normal thyroid gland and is an amiodarone-induced destructive process of the thyroid. Management differs in the two forms of AIT, since Type 1 usually responds to combined thionamides and potassium perchlorate therapy, while Type 2 is generally responsive to glucocorticoids. Mixed forms, characterized by coexistence of excess thyroid hormone synthesis and destructive phenomena, may require a combination of the two therapeutic regimens. In this cross-sectional prospective study, 55 consecutive untreated patients, whose AIT was subtyped according to clinical and biochemical criteria, were evaluated to assess the specificity of color flow doppler sonography (CFDS) and thyroidal radioiodine uptake (RAIU) in the differential diagnosis of AIT. Sixteen patients (6 men, 10 women, age 66+/-13 yr), who had diffuse or nodular goiter with or without circulating thyroid autoantibodies, were classified as Type 1 AIT; 39 patients (27 men, 12 women, age 65+/-13 yr) with apparently normal thyroids were classified as Type 2 AIT. All Type 1 patients had normal or increased thyroidal vascularity on CFDS, while Type 2 AIT patients had absent vascularity (p<0.0001). Thirteen Type 1 AIT patients had inappropriately normal or elevated thyroidal 3-h and 24-h RAIU values (range 6-37% and 10-58%, respectively), in spite of elevated values of urinary iodine excretion; the remaining 3 patients (two with nodular goiter, one with a thyroid adenoma) had low 3-h and 24-h RAIU values (range 1.1-3.0% and 0.9-4.0%, respectively). The latter patients, who were unresponsive to the combination of methimazole and potassium perchlorate, became euthyroid after the addition of glucocorticoids. Thirty-eight Type 2 AIT patients had low 3-h and 24-h RAIU values (range 0.4-3.7% and 0.2-3.0%, respectively), but one had inappropriately normal 3-h and 24-h RAIU values (6% and 13%, respectively). In conclusion, CFDS can accurately distinguish between Type 1 and Type 2 AIT, and in general the CFDS pattern is concordant with the thyroid RAIU. However, in 4 out of 55 patients (7%) the thyroid RAIU was discrepant, probably reflecting the coexistence of Type 1 and Type 2 AIT. Thus, assessment of both CFDS and RAIU may provide a more accurate subtyping of AIT and help in selecting the appropriate therapy. Finally, in long standing iodine sufficient areas, such as the United States, where the thyroid RAIU is consistently low irrespective of the etiology of the AIT, CFDS offers a rapid and available method to differentiate between Type 1 and Type 2 AIT.

Role for inner ring deiodination preventing transcutaneous passage of thyroxine

Creams containing thyroid hormone are commonly employed for cosmetic purposes. To verify whether T(4) applied to the skin surface can enter the bloodstream either directly or as a metabolite, a cream containing L-T(4) [3,5,3',5'-tetraiodothyronine (T(4))] was self-applied by volunteers for 2 wk. No significant variations in urinary iodide, TSH, and serum (total and free) T(4) and T(3) concentrations were observed at any time relative to pretreatment values, whereas rT(3) concentrations increased significantly 6 and 12 h after cream application. The increased rT(3) concentration led us to investigate the presence of inner ring type III deiodinase (D3) activity in human skin. Using human surgical discard skin, we found that T(4) can be carried across human epidermis in a liposome cream. Substantial inner ring deiodination was suggested by the fact that only 10% of transferred thyroid hormone remained as T(4), and T(3) was not detected. We then measured D3 activity in a surgical skin specimen. The K(m) for T(3) was 1.74 nmol/liter, and the maximum velocity was 23.5 fmol/microg microsomal protein/h. In conclusion, our study indicates that normal human skin serves as a substantial, but incomplete, barrier to T(4) passage. D3 plays an important role in augmenting T(4) blockade by inactivating T(4) to rT(3).

Treatment of type II amiodarone-induced thyrotoxicosis by either iopanoic acid or glucocorticoids: a prospective, randomized study

Amiodarone-induced thyrotoxicosis (AIT) may occur either in the presence of underlying thyroid disease (type I AIT) or in apparently normal thyroid glands (type II AIT). Type II AIT, a destructive thyroiditis, often favorably responds to glucocorticoids. Iopanoic acid (IopAc) is an iodinated cholecystographic agent that inhibits deiodinase activity and reduces the conversion of T(4) toT(3). It has recently been reported that cholecystographic agents restore euthyroidism in patients with type II AIT. We describe the results of a prospective randomized study conducted in 12 patients with type II AIT treated with either iopanoic acid (group A, n = 6) or glucocorticoids (group B, n = 6). Serum free T(3) levels normalized rapidly in both groups after 7 d, from 0.75 +/- 0.20 ng/dl (11.5 +/- 3.1 pmol/liter) to 0.46 +/- 0.10 ng/d (7.1 +/- 1.7 pmol/liter), P < 0.01, and from 0.58 +/- 0.10 ng/dl (9.0 +/- 1.2 pmol/liter) to 0.34 +/- 0.03 ng/dl (5.2 +/- 0.5 pmol/liter), P < 0.003, in groups A and B, respectively (P = NS). Serum free T(4) levels reduced at 6 months in group B [from 2.70 +/- 0.32 ng/dl (35.1 +/- 4.1 pmol/liter) to 1.0 +/- 0.04 ng/dl (13.4 +/- 0.6 pmol/liter), P < 0.0001] but not in group A (from 2.90 +/- 0.6 ng/dl (38.0 +/- 7.5 pmol/liter) to 2.30 +/- 0.4 ng/dl (35.6 +/- 6.1 pmol/liter, P = 0.39; P = 0.005 group B vs. group A). All patients in both groups became euthyroid and had their amiodarone-induced destructive thyroiditis cured as defined by normalization of both serum free T(4) and free T(3) levels, during both drugs therapy. However, patients in group B were cured more rapidly than patients in group A (43 +/- 34 d vs. 221 +/- 111 d, respectively, P < 0.002). This study shows that, albeit both drugs are effective, glucocorticoids are probably the drug of choice for more rapidly curing type II AIT.

Three-hour spontaneous GH secretion profile is as reliable as oral glucose tolerance test for the diagnosis of acromegaly

The diagnosis of acromegaly, in an appropriate clinical context, usually relies on lack of GH suppression below 1 microg/l during OGTT coupled with elevated IGF-I levels. On the other hand, in normal subjects glucose-induced inhibition of GH secretory bursts without any further decrease of interpulse GH levels had already been shown. Based on the foregoing, we aimed to compare the diagnostic reliability of OGTT-induced GH nadir with that recorded during 3-h spontaneous GH secretion. In 59 acromegalic patients (17 male and 42 female, age, mean +/- SE 51.5 +/- 1.9, range 21-76 yr) and in 82 normal subjects (43 male and 39 female, age, mean +/- SE 35.7 +/- 1.5, range 15-72 yr) GH secretion was evaluated every 30 min from 0 to 180 min during slow saline infusion or OGTT (75 g at 0 min). A nadir GH concentration below 1 microg/l was recorded in all normal subjects either during OGTT or saline infusion if GH secretion was evaluated over 180 min. In contrast in acromegalic patients a nadir GH concentration below 1 microg/l never occurred in both conditions. This study shows that a 3-h spontaneous GH profile is as reliable as OGTT in the diagnosis of active acromegaly.

Microvascular density and vascular endothelial growth factor expression in normal pituitary tissue and pituitary adenomas

Microvessel density (MVD) represents a measure of angiogenesis and may be used as an indicator of neoplastic aggressiveness. Vascular endothelial growth factor (VEGF) plays a pivotal role as angiogenic promoter by stimulating endothelial cell proliferation and migration and enhancing vascular permeability. The aim of this study was to investigate MVD and VEGF expression in human pituitary adenomas and normal pituitary gland tissues by immunohistochemistry, and to correlate data with clinical characteristics. Fragments from 46 pituitary adenomas (18 non-functioning, 12 ACTH-secreting, 12 GH-secreting, 4 PRL-secreting) and 19 specimens of normal anterior pituitary gland obtained at surgery were evaluated. MVD in normal anterior pituitary was significantly higher than in tumors (69.2 +/- 28.5 vs 29.3 +/- 19.7; p < 0.0001). Within adenomas, no difference was found in MVD when different histotype, size, sex, age, rate of recurrence or medical pre-surgical treatment were considered. The degree of vascularity was somewhat related only to clinical invasiveness, as evaluated by pre-surgical MRI grading (grade 0 p < 0.05 vs grade 1 and vs grade 2). No statistically significant difference in VEGF expression was found between normal tissue and adenomas and among tumors of different histotype (p = 0.3978). Size, sex, age, rate of recurrence and medical pre-surgical treatment did not influence VEGF expression. No correlation was found between MVD and VEGF expression. In conclusion, MVD was reduced in pituitary adenomas with respect to normal gland. VEGF expression is however well preserved in adenomas and this might contribute to adequate tumoral vascular supply with complex mechanisms other than endothelial cells proliferation.

Preparation with iopanoic acid rapidly controls thyrotoxicosis in patients with amiodarone-induced thyrotoxicosis before thyroidectomy

BACKGROUND

Amiodarone-induced thyrotoxicosis (AIT) may develop either in apparently normal glands (type II AIT) or in the presence of thyroid abnormalities (type I AIT). Sometimes AIT is resistant to conventional treatment. Thyroidectomy was used in patients with AIT, but in patients who are thyrotoxic it may be hazardous. METHODS; Seven patients with AIT (6 type I and 1 type II, 5 men, 2 women, mean age 70 years [range, 60-82 years]) were prepared for total thyroidectomy with a short course of iopanoic acid (1 g/day orally for a mean of 13 days), an oral iodinated cholecystographic agent inhibiting 5'-deiodinase and causing a reduction in the peripheral conversion of thyroxine to triiodothyronine. Mean thyroid volume was 64 mL (range, 10-145 mL).

RESULTS

Mean serum-free triiodothyronine levels decreased from 20 +/- 16.7 pmol/L to 6 +/- 2 pmol/L (P =.0004), whereas serum-free thyroxine values remained unchanged. Euthyroidism was rapidly (7-20 days) restored, allowing an uncomplicated total thyroidectomy in all patients and the ability to continue amiodarone therapy in 6 patients. None had increased surgical bleeding, recurrent nerve palsy, or hypoparathyroidism. No cardiovascular complications occurred.

CONCLUSIONS

Iopanoic acid is an effective drug allowing rapid control of hyperthyroidism in AIT.

Treatment with lithium prevents serum thyroid hormone increase after thionamide withdrawal and radioiodine therapy in patients with Graves' disease

Serum thyroid hormone concentrations increase after radioiodine (RAI) therapy for Graves' disease. This phenomenon has been ascribed to either antithyroid drug withdrawal before RAI therapy or release of preformed thyroid hormones into the bloodstream from the RAI-damaged thyroid. Lithium blocks the release of iodine and thyroid hormones from the thyroid, thus enhancing the effectiveness of RAI therapy. Changes in serum-free thyroxine (FT4) and triiodothyronine (FT3) levels after methimazole (MMI) discontinuation and RAI therapy were evaluated in a prospective, randomized, control study of 36 patients with Graves' disease. After a 3- to 4-month course of MMI, patients were assigned to one of three groups: G1 (RAI alone); G2 (RAI plus lithium for 6 d starting on the day of RAI therapy); or G3 (RAI plus lithium for 19 d starting on the day of MMI withdrawal). G1-G2 patients had an increase in serum FT4 and FT3 levels from 13.5 +/- 6.5 to 19.8 +/- 9.2 pmol/liter and 5.0 +/- 2.0 to 8.0 +/- 4.8 pmol/liter, respectively (P < 0.0001), 2-5 d after MMI withdrawal, but G3 patients showed no changes. In the 30 d after RAI therapy, mean serum FT4 values increased in G1 patients (P = 0.02), peaking at 3-7 d (P < 0.05) but not in G2 and G3 patients. Serum FT3 levels decreased in G1, G2, and G3 (P = 0.03, P = 0.001, P = 0.02, respectively). Hyperthyroidism was cured in 8 of 12 G1 patients, 11 of 12 G2 patients, and 11 of 12 G3 patients (P = 0.31). Control of hyperthyroidism was prompter in G2 (P = 0.08) and G3 (P < 0.05) than in G1 patients. Patients in the three groups received a similar dose of RAI, but the committed radiation to the thyroid was higher in G3 (563 +/- 174 Gray) and G2 (588 +/- 347 Gray) than in G1 (429 +/- 204 Gray) (P < 0.03). In conclusion, the results of the present study demonstrate that: 1) MMI withdrawal is associated with a slight rise in serum thyroid hormone levels; 2) a further increase occurs after RAI therapy; 3) changes in serum thyroid hormone concentrations are prevented by lithium; and 4) the increased effectiveness of RAI therapy in lithium-treated patients is related to the increased RAI retention in the thyroid gland. Accordingly, a short course of lithium therapy can be considered a useful adjunct to RAI therapy to obtain a prompter control of thyrotoxicosis and avoid its transient exacerbation because of MMI withdrawal and RAI administration.

Prostate-specific antigen is increased in female patients with Cushing's disease

Prostate-specific antigen (PSA) is a serine protease with chymotripsine-like enzymatic activity, produced primarily by the prostate gland. It is widely used as a marker of androgen sensitive-prostate cancer. Likewise, women with androgen-dependent hirsutism have increased serum PSA levels. The aim of the present study was to investigate whether female patients with Cushing's disease had increased serum PSA concentrations. We studied 22 patients with active Cushing's disease. Twelve out of 22 patients were also evaluated after remission of the disease. Forty normal women with no signs of hirsutism served as controls. Mean serum PSA levels were higher in patients with active Cushing's disease than controls (p=0.005). Mean serum PSA levels decreased after remission of the disease (33.7+/-63.3 pg/ml vs 2.2+/-3.0 pg/ml, p<0.002, in active and cured patients, respectively). All patients with high serum PSA levels had a normalization of this parameter after the disease was cured. Serum T, DHEAS and delta4 concentrations decreased after the remission of Cushing's disease. A positive correlation was found between serum PSA and T values (r=0.6, p<0.05). In conclusion, elevated serum PSA values are markers of androgen activity in female with Cushing's disease and their normalization may represent an additional index of remission of the disease.

Submandibular salivary gland volume is increased in patients with acromegaly

OBJECTIVE

Acromegaly is characterized by an enlargement of various organs. The aim of the present study was to evaluate whether acromegalic patients have an increased volume of submandibular salivary glands.

DESIGN AND SUBJECTS

Prospective study on 40 consecutive acromegalic patients (18 male, 22 female; mean age +/- SD, 50 +/- 13 years, range 22-74 years) submitted to submandibular salivary gland ultrasound. Among acromegalic patients, 15 had active and untreated disease (Acro-U), 13 were under long-acting somatostatin analogue therapy (Acro-SA), 12 were in remission after surgery (Acro-R). Two hundred subjects (90 male, 110 female, mean age +/- SD, 50 +/- 11 years, range 23-74 years) matched for age, sex and body mass index served as controls.

MEASUREMENTS

Submandibular salivary gland volume was measured in all acromegalic patients and normal subjects by ultrasound and calculated by the ellipsoid model. Serum GH and IGF-I concentrations were measured in all subjects.

RESULTS

Acro-U patients had higher serum IGF-I levels (691 +/- 235 microg/l) than Acro-R (174 +/- 74 microg/l), Acro-SA (436 +/- 239 microg/l) or controls (151 +/- 66 microg/l) (P < 0.0001, P = 0.008, P < 0.0001, respectively). The mean submandibular salivary gland volume was higher in acromegalic patients than in controls: Acro-U 18.1 +/- 3.3 ml, Acro-SA 16.2 +/- 3.3 ml, Acro-R 15.7 +/- 3.0 ml and controls 8.2 +/- 2.4 ml (P < 0.0001). Differences among subgroups of Acro patients were not significant. Enlargement of the submandibular salivary glands was present in 35/40 (87.5%) acromegalic patients. A positive correlation between serum IGF-I (P < 0.0001), GH (P < 0.0001) and submandibular salivary gland volume was found.

CONCLUSIONS

Acromegalic patients have an increased volume of submandibular salivary glands, independently of the activity of disease.

Thyroid vascularity is increased in patients with active acromegaly

OBJECTIVE

To determine whether acromegalic patients have increased thyroidal vascularity and blood flow on colour flow Doppler sonography (CFDS).

DESIGN

Prospective study of consecutive patients.

PATIENTS

Twenty-four acromegalic patients (11 men, 13 women, age 49 +/- 9 years); 38 patients with nontoxic goitre (NTG; 12 men, 26 women, age 50 +/- 7 years); 36 normal subjects (controls; 16 men, 20 women, age 46 +/- 9 years). Among acromegalic patients, 10 had active, untreated disease (Acro-U), seven were in remission after surgery (Acro-R), seven had active disease under treatment with somatostatin analogues (SMSa) (Acro-SA) (Sandostatin LAR, 20 mg, every 28 days).

MEASUREMENTS

CFDS pattern and intrathyroidal peak systolic velocity (PSV) were determined by a colour Doppler system with a 7.5-MHz linear transducer. PSV measurements were made at the level of the intrathyroidal arteries (normal values 3.8 +/- 1.0 cm/s). Thyroid volume was calculated by the ellipsoidal model. Assays included measurements of serum GH, IGF-I, free T4, free T3, TSH, antithyroglobulin (anti-Tg) and antithyroperoxidase (anti-TPO) antibodies, TSH-receptor antibodies (TRAb).

RESULTS

Serum GH (+/- SD) and IGF-I (+/- SD) levels were: Acro-U: GH 26 +/- 31 microg/l, IGF-I 783 +/- 299 microg/l; Acro-SA: GH 15 +/- 25 microg/l, IGF-I 366 +/- 212 microg/l; Acro-R: GH 1.3 +/- 1.0 microg/l, IGF-I 241 +/- 99 microg/l. To convert values for serum GH to mU/l multiply by 2.6; to convert values for serum IGF-I to nmol/l multiply by 0.13075. All controls had CFDS pattern 0 (absent vascularity or minimal spots); among NTG patients, 36 had pattern 0 and two had pattern I (parenchymal blood flow with patchy uneven distribution). Five patients with acromegaly had pattern 0, 12 had pattern I and seven pattern II (mild increase of colour flow Doppler signal with patchy distribution). Among the five acromegalic patients with pattern 0, three were Acro-R and two were Acro-SA. Among patients with pattern I, six were Acro-U, two were Acro-SA and four were Acro-R. Among patients with pattern II, four were Acro-U and three Acro-SA; two patients of the latter group had elevated serum IGF-I under SMSa treatment. Intrathyroidal PSV was 3.8 +/- 1.0 cm/s in controls, 4.0 +/- 1.1 cm/s in NTG, 7.4 +/- 0.8 cm/s in Acro-U, 4.9 +/- 1.3 cm/s in Acro-SA treatment and 4.5 +/- 1.0 in Acro-R. (Acro-U vs. Acro-SA, P = 0.0003; vs. Acro-R, Controls, or NTG, P < 0.0001). PSV values in Acro-SA were higher than those observed in NTG or controls (P = 0.05, P = 0.01, respectively); PSV values in Acro-R did not differ from those in NTG or controls. Intrathyroidal PSV values were correlated with serum IGF-I (r = 0.73, P < 0.0001) and, although less strongly, GH levels (r = 0.54, P = 0.01). Goitre was present in 19 of 24 patients; diffuse in three and nodular in 16. Thyroid function was normal in all subgroups of acromegalic patients. Anti-Tg, anti-TPO antibodies and TRAb were negative in all subjects.

CONCLUSIONS

Patients with active acromegaly have increased intrathyroidal blood flow (colour flow Doppler sonography pattern II, increased peak systolic velocity values); this was not observed in the large majority of patients under treatment with somatostatin analogues and in any patient in remission. Accordingly, colour flow Doppler sonography and peak systolic velocity measurements may be considered an additional useful peripheral parameter for rapid assessment of the activity of acromegaly.

Peroxisome proliferator activated receptor gamma expression is reduced in the colonic mucosa of acromegalic patients

Acromegalic patients have an increased prevalence of colonic polyps, due to the elevated serum insulin like growth factor (IGF)-I levels. The mechanisms underlying this process are poorly understood. Peroxisome proliferator activated receptor (PPAR)gamma, a nuclear receptor that regulates adipocyte differentiation, is highly expressed in the human colonic mucosa, where it induces growth inhibition and cell differentiation. In the present study we evaluated the expression of PPARgamma in the bioptic samples of colonic mucosa from 22 patients with acromegaly (Acro) and 13 normal subjects (CONTROLS) matched for age and sex. Among Acro patients, 10 had active, untreated disease (AcroUntr), 6 were in remission after surgery (AcroRem), and 6 had active disease under treatment with somatostatin analogs (AcroSMSa). Serum GH and IGF-I (mean +/- SD) levels were as follows: AcroUntr: GH, 36 +/- 40 microg/l; IGF-I, 769 +/- 298 microg/l; AcroRem: GH, 1.0 +/- 1.3 microg/l; IGF-I, 248 +/- 96 microg/l; AcroSMSa: GH, 7.8 +/- 12 microg/l; IGF-I, 429 +/- 221 microg/l;

CONTROLS

GH, 0.8 +/- 0.7 microg/l; IGF-I, 203 +/- 67 microg/l. In the CONTROLS the level of expression of PPARgamma mRNA was 15230 +/- 891 transcripts. Patients with AcroUntr had 2750 +/- 688 transcripts of PPARgamma. (p < 0.0001) vs. CONTROLS); patients AcroSMSa had 4629 +/- 1286 transcripts of PPARgamma. (p = NS vs AcroUntr, p = 0.0002 vs. CONTROLS); patients with AcroRem had 8261 +/- 2481 transcripts of PPARgamma (p = 0.008 vs. AcroUntr, p = NS vs. AcroSMSa, p = 0.007 vs. CONTROLS). A significant inverse correlation was found between serum IGF-I concentrations and the level of expression of PPARgamma (r = 0.43, p = 0.03). In conclusion, patients with active Acro have a reduced expression of PPARgamma in the colonic mucosa, which appears be related to the increased serum IGF-I levels and might lead to an increased prevalence of colonic polyps.

GH secretion is impaired in patients with primary hyperparathyroidism

The activity of the GH/IGF-I axis as a function of parathyroid activity and calcium metabolism in humans has never been assessed. To address this issue, we studied 18 patients (5 men, 13 women; age range, 23-76 yr; mean, 61 yr) with primary hyperparathyroidism (PHP) due to solitary parathyroid adenoma. GH secretion was evaluated by serum IGF-I levels, spontaneous mean GH secretion over two morning hours, and GH response to arginine (ARG) alone or combined with GHRH. In five patients, serum GH concentrations were measured every 20 min for 24 h, and deconvolution analysis was performed. A group of 35 age- and sex-matched normal subjects served as controls. Mean serum IGF-I levels in PHP were lower than in normal controls, and in six PHP patients individual serum IGF-I levels were below the age-related normal range. The mean (+/-SE) peak GH response to ARG alone in PHP patients was significantly lower than in normal subjects (4.0 +/- 1.0 vs. 22.0 +/- 1.3 microg/liter; P < 0.001). Likewise, the mean (+/-SE) peak GH response to ARG plus GHRH was reduced in PHP patients (9.9 +/- 0.9 vs. 38.0 +/- 3.5 microg/liter; P < 0.001). The mean GH concentration over two morning hours in PHP was lower (0.20 +/- 0.05 vs. 1.34 +/- 0.31 microg/liter; P < 0.001). The mean GH concentration over 24 h in five PHP patients was lower than in six normal controls (0.3 +/- 0.1 vs. 0.7+/- 0.1 microg/liter; P < 0.05); the deconvolution analysis showed that 24-h GH production rate (3.0 +/- 1.7 vs. 28.2 +/- 4.7 microg/liter.d; P < 0.05) and mean secretory burst mass (1.2 +/- 0.7 vs. 10.5 +/- 2.6 microg/liter; P < 0.05), but not pulse frequency, were lower in PHP patients than in normal controls. GH half-life and approximate entropy values of 24-h GH profiles were similar in PHP patients and normal controls. No correlation was found between serum-ionized calcium or PTH levels and spontaneous or stimulated GH levels in PHP patients. In conclusion, this study demonstrates that PHP patients have a reduction in both spontaneous and stimulated GH secretion. Accordingly, PHP should be mentioned as a further example of a metabolic condition in which GH secretion in adults is reduced.