Paradoxical GH increase after oral glucose load in subjects with and without acromegaly.

OBJECTIVE: A paradoxical GH rise after the glucose load (GH-Par) is described in about one-third of acromegalic patients. Here, we evaluated the GH profile in subjects with and without acromegaly aiming to refine the definition of GH-Par. DESIGN: Observational case-control study. METHODS: Our cohort consisted of 60 acromegalic patients, and two groups of subjects presenting suppressed GH (< 0.4 µg/L) and high (non-acro↑IGF-1, n = 116) or normal IGF-1 levels (non-acro, n = 55). The distribution of GH peaks ≥ 120% from baseline, insulin, and glucose levels were evaluated over a 180-min time interval after glucose intake. RESULTS: A similar proportion of subjects in all three groups shows a GH ratio of ≥ 120% starting from 120 min. Re-considering the definition of paradoxical increase of GH within 90 min, we observed that the prevalence of GH peaks ≥ 120% was higher in acromegaly than in non-acro↑IGF-1 and non-acro (respectively 42%, 16%, and 7%, both p < 0.001). In patients without GH-Par, a late GH rebound was observed in the second part of the curve. Higher glucose peak (p = 0.038), slower decline after load, 20% higher glucose exposure (p = 0.015), and a higher prevalence of diabetes (p = 0.003) characterized acromegalic patients with GH-Par (with respect to those without). CONCLUSIONS: GH-Par response may be defined as a 20% increase in the first 90 min after glucose challenge. GH-Par, common in acromegaly and associated with an increased prevalence of glucose metabolism abnormalities, is found also in a subset of non-acromegalic subjects with high IGF-1 levels, suggesting its possible involvement in the early phase of the disease.

The GIP/GIPR axis is functionally linked to GH-secretion increase in a significant proportion of gsp- somatotropinomas.

OBJECTIVE: Glucose-dependent insulinotropic polypeptide receptor (GIPR) overexpression has been recently described in a proportion of gsp- somatotropinomas and suggested to be associated with the paradoxical increase of GH (GH-PI) during an oral glucose load. DESIGN AND METHODS: This study was aimed at linking the GIP/GIPR pathway to GH secretion in 25 somatotropinomas-derived primary cultures and correlating molecular with clinical features in acromegalic patients. Given the impairment of the GIP/GIPR axis in acromegaly, an additional aim was to assess the effect of GH/IGF-1 stimulation on GIP expression in the enteroendocrine cell line STC-1. RESULTS: Nearly 80% of GIPR-expressing somatotropinomas, all of them negative for gsp mutations, show increased GH secretion upon GIP stimulation, higher sensitivity to Forskolin but not to somatostatin analogs. Besides increased frequency of GH-PI, GIPR overexpression does not appear to affect acromegalic patients' clinical features. In STC-1 cells transfected with GIP promoter-driven luciferase vector, IGF-1 but not GH induced dose-dependent increase in luciferase activity. CONCLUSIONS: We demonstrate that GIPR mediates the GH-PI in a significant proportion of gsp- acromegalic patients. In these cases, the stimulatory effect of IGF-1 on GIP promoter support the hypothesis of a functional GH/IGF-1/GIP axis. Further studies based on larger cohorts and the development of a stable transgenic model with inducible GIPR overexpression targeted to pituitary somatotroph lineage will be mandatory to establish the real role of GIPR in the pathogenesis of somatotropinomas.

A multicenter experience on the prevalence of ARMC5 mutations in patients with primary bilateral macronodular adrenal hyperplasia: from genetic characterization to clinical phenotype.

ARMC5 mutations have recently been identified as a common genetic cause of primary bilateral macronodular adrenal hyperplasia (PBMAH). We aimed to assess the prevalence of ARMC5 germline mutations and correlate genotype with phenotype in a large cohort of PBMAH patients. A multicenter study was performed, collecting patients from different endocrinology units in Italy. Seventy-one PBMAH patients were screened for small mutations and large rearrangements in the ARMC5 gene: 53 were cortisol-secreting (two with a family history of adrenal hyperplasia) and 18 were non-secreting cases of PBMAH. Non-mutated and mutated patients' clinical phenotypes were compared and related to the type of mutation. A likely causative germline ARMC5 mutation was only identified in cortisol-secreting PBMAH patients (one with a family history of adrenal hyperplasia and ten apparently sporadic cases). Screening in eight first-degree relatives of three index cases revealed four carriers of an ARMC5 mutation. Evidence of a second hit at somatic level was identified in five nodules. Mutated patients had higher cortisol levels (p = 0.062), and more severe hypertension and diabetes (p < 0.05). Adrenal glands were significantly larger, with a multinodular phenotype, in the mutant group (p < 0.01). No correlation emerged between type of mutation and clinical parameters. ARMC5 mutations are frequent in cortisol-secreting PBMAH and seem to be associated with a particular pattern of the adrenal masses. Their identification may have implications for the clinical care of PBMAH cases and their relatives.

Acromegaly Is More Severe in Patients With AHR or AIP Gene Variants Living in Highly Polluted Areas.

CONTEXT: An increased prevalence of acromegaly was found some years ago in a highly polluted area in North-Eastern Sicily, where high concentration of nonmethane hydrocarbons, volatile organic compounds, and cadmium was found. Aryl hydrocarbon receptor (AHR) pathway has a key role in detoxification of these compounds and in tumorigenesis. OBJECTIVE: We correlated the occurrence of AHR and/or AHR-interacting protein (AIP) gene variants with acromegaly severity according to pollution exposition. DESIGN, SETTING, and PATIENTS: This was an observational, perspective study conducted over 7 years in four Italian referral centers for pituitary diseases in which 210 patients with acromegaly were enrolled between 2008 and 2015. INTERVENTION: Genetic screening of patients for AHR and AIP variants. MAIN OUTCOME MEASURES: Clinical, biochemical, and radiological data of patients with and without AIP and/or AHR gene variants, living in polluted (high-risk for health, [HR]) or nonpolluted (NP) areas of five Italian regions were evaluated and compared. RESULTS: Among the 23 patients from HR areas, nine showed AHR or AIP variants. Mean IGF-I levels and pituitary tumor diameter were significantly higher in these nine patients (HR/VAR+) than in the other 14 (HR/VAR−) and in the 187 from NP areas (44 NP/VAR+). Somatostatin analogs significantly decreased mean GH and IGF-I levels in patients from NP areas and in HR/VAR− (GH P < .05; IGF-I times the upper limit of normal P < .01) but not in HR/VAR+ group. CONCLUSIONS: Genetic variants potentially inducing functional abnormalities of the aryl hydrocarbon receptor (AHR) pathway are associated with a more severe acromegaly, increased pituitary tumor size, and somatostatin analog resistance in patients living in HR areas.

Analysis of GPR101 and AIP genes mutations in acromegaly: a multicentric study.

This multicentric study aimed to investigate the prevalence of the G protein-coupled receptor 101 (GPR101) p.E308D variant and aryl hydrocarbon receptor interacting protein (AIP) gene mutations in a representative cohort of Italian patients with acromegaly. 215 patients with GH-secreting pituitary adenomas, referred to 4 Italian referral centres for pituitary diseases, have been included. Three cases of gigantism were present. Five cases were classified as FIPA. All the patients have been screened for germline AIP gene mutations and GPR101 gene p.E308D variant. Heterozygous AIP gene variants have been found in 7 patients (3.2 %). Five patients carried an AIP mutation (2.3 %; 4 females): 3 patients harboured the p.R3O4Q mutation, one had the p.R304* mutation and the last one the IVS3+1G>A mutation. The prevalence of AIP mutations was 3.3 % and 2.8 % when considering only the patients diagnosed when they were <30 or <40-year old, respectively. Furthermore, 2.0 % of the patients with a pituitary macroadenoma and 4.2 % of patients resistant to somatostatin analogues treatment were found to harbour an AIP gene mutation. None of the patients was found to carry the GPR101 p.E308D variant. The prevalence of AIP gene mutations among our sporadic and familial acromegaly cases was similar to that one reported in previous studies, but lower when considering only the cases diagnosed before 40 years of age. The GPR101 p.E308D change is unlikely to have a role in somatotroph adenomas tumorigenesis, since none of our sporadic or familial patients tested positive for this variant.

An analysis of different therapeutic options in patients with Cushing's syndrome due to bilateral macronodular adrenal hyperplasia: a single-centre experience.

CONTEXT: Bilateral macronodular adrenal hyperplasia (BMAH) is a rare form of Cushing's syndrome (CS). A variety of in vivo tests to identify aberrant receptor expression have been proposed to guide medical treatment. Unilateral adrenalectomy (UA) may be effective in selected patients, but little is known about recurrence during follow-up. OBJECTIVE: To describe a series of patients with BMAH and CS treated by different approaches, with a particular focus on the benefit of UA. DESIGN AND PATIENTS: We retrospectively assessed 16 patients with BMAH and CS (11 females, five males), analysing the in vivo cortisol response to different provocative tests. Twelve of the 16 patients underwent UA and were monitored over the long term. RESULTS: Based on in vivo test results, octreotide LAR or propranolol was administered in one case of food-dependent CS and two patients with a positive postural test. A significant improvement in biochemical values was seen in all patients but with limited clinical response. UA was performed in 12 patients, producing long-term remission in three (106 ± 28 months; range: 80-135), recurrence in eight (after 54 ± 56 months; range 12-180) and persistence in one other. Four patients subsequently underwent contralateral adrenalectomy for overt CS, one received ketoconazole, and four other patients remain under observation for subclinical CS. CONCLUSIONS: Medical treatment based on cortisol response to provocative tests had a limited role in our patients, whereas UA was useful in some of them. Although recurrence is likely, the timing of onset is variable and close follow-up is mandatory to identify it.

Venous thromboembolism in patients with Cushing's syndrome: need of a careful investigation of the prothrombotic risk profile.

A high incidence of venous thromboembolic (VTE) complications has been reported in Cushing's syndrome (CS), mostly post-operatively and attributable to hypercoagulability. The prevalence of symptomatic VTE was investigated retrospectively in 58 consecutive CS patients in relation to acquired and genetic thrombotic risk factors. Eight CS patients (14 %) developed VTE (group A), 3 of them related and 5 unrelated to surgery. These patients had higher urinary free cortisol (p = 0.01) and VWF levels (p = 0.02) than the 50 patients without VTE (group B), as well an increase in the hemostatically more efficient, high-molecular-weight VWF multimers (p = 0.002). Factor V Leiden and the prothrombin gene 20210A variants (the most common inherited thrombophilic defects) were more represented in group A than in group B, as was the genotype GCAG/GCAG of the VWF gene promoter, known to hyperinduce VWF upregulation under cortisol excess. All but one of the patients with VTE unrelated to surgery had at least four acquired and at least one inherited risk factor. Severe hypercortisolism and VWF levels with increased haemostatic activity are strongly associated with VTE in CS. VTE episodes unrelated to surgery are attributable to the synergistic action of acquired and inherited thrombotic risk factors. Based on these observations, we believe that severely affected CS patients should be screened for coagulation disorders and receive antithrombotic prophylaxis whenever they have concomitant prothrombotic risk factors.

The glucose-dependent insulinotropic polypeptide receptor is overexpressed amongst GNAS1 mutation-negative somatotropinomas and drives growth hormone (GH)-promoter activity in GH3 cells.

Somatic mutations in the GNAS1 gene, encoding the α-subunit of the heterotrimeric stimulatory G protein (Gαs), occur in approximately 40% of growth hormone (GH)-secreting pituitary tumours. By altering the adenylate cyclase-cAMP-protein kinase A pathway, they unequivocally give somatotroph cells a growth advantage. Hence, the pathogenesis of somatotropinomas could be linked to anomalies in receptors coupled to the cAMP second-messenger cascade. Among them, the glucose-dependent insulinotropic polypeptide receptor (GIPR) is already known to play a primary role in the impaired cAMP-dependent cortisol secretion in patients affected by food-dependent Cushing's syndrome. In the present study, 43 somatotropinomas and 12 normal pituitary glands were investigated for GIPR expression by quantitative reverse transcriptase-polymerase chain reaction, western blotting and immunohistochemistry. Tumoural specimens were also evaluated for GNAS1 mutational status. The effect of GIPR overexpression on cAMP levels and GH transcription was evaluated in an in vitro model of somatotropinomas, the GH-secreting pituitary cell line GH3. GIPR was expressed at higher levels compared to normal pituitaries in 13 GNAS1 mutation-negative somatotropinomas. GIP stimulated adenylyl cyclase and GH-promoter activity in GIPR-transfected GH3 cells, confirming a correct coupling of GIPR to Gαs. In a proportion of acromegalic patients, GIPR overexpression appeared to be associated with a paradoxical increase in GH after an oral glucose tolerance test. Whether GIPR overexpression in acromegalic patients may be associated with this paradoxical response or more generally involved in the pathogenesis of acromegaly, as suggested by the mutually exclusive high GIPR levels and GNAS1 mutations, remains an open question.

Adrenal lesions in acromegaly: do metabolic aspects and aryl hydrocarbon receptor interacting protein gene have a role? Evaluation at baseline and after long-term follow-up.

BACKGROUND: Adrenal lesions are discovered in acromegaly more frequently than in general population, without relationship with primary disease. Some patients, carriers of aryl hydrocarbon receptor interacting protein (AIP) gene mutations, developed an adrenal neoplasm. AIM: To evaluate the role of metabolic and genetic aspects and the follow-up of adrenal nodules in acromegaly. MATERIAL AND METHODS: We studied 69 acromegalic patients (30 male and 39 female, 56 ± 15 yr) who had been referred to the Endocrinology Unit of Padua. In all patients we determined body mass index (BMI) and waist-to-hip ratio (WHR); we performed an oral glucose tolerance test (OGTT) whenever possible. If adrenal computed tomography revealed a lesion, the patient underwent an endocrine and genetic study. RESULTS: Adrenal lesions were identified in 14 patients and were not related to gender, duration of disease, GH or IGF-I concentrations, basal and after-OGTT glucose and insulin levels, log(HOMA-IR) and Quantitative Insulin Sensitivity Check Index (QUICKI) values, whereas BMI and WHR were higher in patients with adrenal lesions. Baseline endocrine and radiological study revealed benign lesions; during mean 4-yr follow-up none of the patients showed hormone excess, even though some lesions increased in size. We did not find any mutation in AIP gene, except heterozygous silent alteration (T48T). CONCLUSIONS: The frequency of non-functioning adrenal lesions in acromegaly is not associated with the considered aspects, except BMI and WHR. The prolonged follow-up showed that these lesions have a tendency to increase in size independently of the control of acromegaly, so a morphological follow- up is recommended.

Adrenal nodules in patients with Cushing's disease: prevalence, clinical significance and follow-up.

UNLABELLED: Adrenal glands in Cushing's disease (CD) range from normal to showing diffuse enlargement in most cases. The finding of nodular lesions has been reported, but information about prevalence and evolution is described in few reports. AIM: To investigate the prevalence of nodular adrenal glands in patients with CD and assess its evolution after disease remission. SUBJECTS AND METHODS: We assessed 41 CD patients' abdominal computed tomography (CT) scans obtained during the active phase of the disease and evaluated the dynamics of ACTH and cortisol secretion. CT was repeated after disease remission in patients with adrenal nodules. RESULTS: Fifteen of 41 patients had nodular and the remaining 26 had normal or enlarged adrenal glands. Patients with nodules were older (45.1 ± 8.8 vs 36.9 ± 12.7 yr; p=0.03) and had longer-standing disease (57.3 ± 56.9 vs 32.9 ± 29.1 months; p=0.05) than patients with normal/enlarged adrenal glands. ACTH (45.4 ± 21.3 vs 70.5 ± 39.1 pg/ml; p=0.04) and urinary free cortisol levels (606.1 ± 512.3 vs 301.0 ± 224.7 µg/day, p=0.01) were significantly lower in patients with adrenal nodules while there were no differences between the groups in terms of dynamic tests results. Post-operative follow-up showed regression or shrinkage of the nodules in 8 out of 10 patients in disease remission. CONCLUSIONS: We found that adrenal nodular glands are a frequent finding in CD in particular in older patients and in those with a longerstanding disease. Nevertheless, a high percentage of nodules regression or shrinking was evidenced in our series after disease remission.

Prevalence of AIP mutations in a large series of sporadic Italian acromegalic patients and evaluation of CDKN1B status in acromegalic patients with multiple endocrine neoplasia.

BACKGROUND: Germline mutations in the aryl hydrocarbon receptor-interacting protein (AIP) gene and the p27(KIP1) encoding gene CDKN1B have been associated with two well-defined hereditary conditions, familial isolated pituitary adenoma (FIPA) and multiple endocrine neoplasia type 4 (MEN4). Somatotropinomas are present in most AIP mutated FIPA kindreds, as well as in two-thirds of MEN4 patients who carry pituitary tumors. METHODS: Germline DNA samples of 131 Italian sporadic acromegalic patients including 38 individuals with multiple tumors, and of six FIPA families (four homogeneous for prolactinomas and two heterogeneous with prolactin/nonfunctioning pituitary adenomas) were collected in a multicentric collaborative study. The prevalence of AIP and CDKN1B gene point mutations and copy number variations were evaluated. RESULTS: Two novel (IVS3+1G>A and c.871G>A) and one previously described (c.911G>A) AIP mutations were detected in four apparently sporadic cases (3.1%) with relatively high age at diagnosis (49+/-18, range 30-67). No mutations/rearrangements were detected in FIPA families. The highly conserved c.871G>A substitution was detected in a patient who also carried a MEN1 mutation suggesting that she is a double heterozygote. The possible pathogenic effect on AIP splicing of the silent substitution c.144G>A found in another patient was ruled out using a minigene-based approach. CDKN1B mutations/rearrangements were neither identified in patients with multiple neoplasia nor in FIPA families. CONCLUSION: AIP is mutated in about 3% of apparently sporadic acromegalic patients. The relatively high age at diagnosis, as well as its sporadic presentation, suggests that these patients are carriers of mutations with reduced pathogenicity. p27(KIP1) is unlikely to represent the common unifying nonendocrine etiology for acromegaly and cancer.

The R304X mutation of the aryl hydrocarbon receptor interacting protein gene in familial isolated pituitary adenomas: Mutational hot-spot or founder effect?

BACKGROUND: Mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene have been described in about 15% of kindreds with familial isolated pituitary adenomas and in a minority of early onset sporadic pituitary adenomas (PA). Among the AIP mutations reported so far, the R304X (AIPR304X) represents, together with the "Finnish mutation" Q14X, the most common one. METHODS: Three AIPR304X Italian families, including a newly reported kindred, have been genotyped for 12 genetic markers surrounding the AIP gene in order to look for a potential founder effect in Italy. Disease penetrance and genotype-phenotype correlations were also addressed. RESULTS: Analysis of chromosome 11' genetic markers revealed a common haplotype in 2 AIPR304X kindreds originating from central Italy. Overall, 17 mutations carriers were identified, including 7 patients and 10 unaffected subjects, respectively, arguing in this case for a disease penetrance of 41%. Mean age at diagnosis was 19.1±6.7 yr old, with females tending to be older than males. Though most PA were somatotropinomas (6/7), a great variability in disease severity was observed, even between subjects sharing the same at-risk haplotype. CONCLUSION: These data provide strong evidence for a new founder effect of the AIPR304X mutation in central Italy and the observed variations in disease severity point out the role of additional genetic or environmental factors in such kindreds.

Food-dependent Cushing's syndrome: from molecular characterization to therapeutical results.

OBJECTIVE: Cortisol secretion in ACTH-independent macronodular adrenal hyperplasia (AIMAH) may be regulated by the aberrant expression of several G-protein-coupled receptors. Bilateral adrenalectomy is the treatment of choice in most cases. We searched for aberrant receptor expression in a patient with AIMAH and evaluated the response to medical and surgical treatment. PATIENT: A 35-year-old woman with amenorrhea, hirsutism, and hypertension presented ACTH-independent cortisol secretion with high androgen levels. Abdominal computed tomography showed bilateral adrenal macronodules (4.5 cm right and 1.0 cm left). Scintigraphy with I(131)-norcholesterol showed bilateral uptake, prevalent on the right side. Several in vivo stimulation tests were assessed before and after treatment and in vitro studies were performed after unilateral adrenalectomy. RESULTS: Plasma cortisol increased after a standard meal test (60%) and oral glucose loading (147%), and the response was blunted by pretreatment with 100 microg s.c. octreotide. The therapy with long-acting release octreotide (octreotide-LAR) showed an improvement in urinary free cortisol (UFC) levels. Unilateral adrenalectomy was performed and histopathology revealed macronodular AIMAH. Cortisol and androgens increased after perifusion of tumoral tissue with glucose-dependent insulinotropic polypeptide (GIP), and GIP and LH-receptor overexpression was found in both the adrenal nodules and the adjacent cortex. After surgery, UFC and androgen levels normalized followed by clinical improvement. CONCLUSIONS: GIP and LH-receptor expression may coexist in AIMAH, influencing the functional and morphological phenotype. Aberrant hormone receptor expression enables specific pharmacological treatment, but long-term studies are needed to evaluate its real efficacy. Unilateral adrenalectomy may be a safe initial option, particularly for asymmetric bilateral adrenal enlargements.

Peroxisome proliferator-activated receptor gamma in the human pituitary gland: expression and splicing pattern in adenomas versus normal pituitary.

Pituitary adenomas are slow-growing tumours arising within the pituitary gland. If secreting, they give rise to well-known syndromes such as Cushing's disease or acromegaly; when hormonally inactive, they come to clinical attention often with local mass effects or pituitary deficiency. Peroxisome proliferator-activated receptor gamma (PPARgamma), a nuclear hormone receptor with a key role in fat and glucose metabolism, but also involved in several neoplasia, has recently been detected in pituitary adenomas. In the present study, we evaluated the occurrence and splicing profile of PPARgamma in 43 cases of pituitary adenoma of different subtypes and compared it to 12 normal pituitary glands. By real-time polymerase chain reaction, PPARgamma was expressed as much in adrenocorticotrophic hormone (ACTH)-secreting and ACTH-silent adenomas as in controls, with a moderate underexpression in somatotrophinomas and prolactinomas and overexpression in 54% of nonfunctioning pituitary adenomas (NFPA). There was no apparent qualitative change in the splicing profile of pathological pituitary glands, nor was the presence of specific isoforms with dominant negative effects against PPARgamma detected. Western blotting revealed similar expression levels in the different subgroups of pituitary adenomas and normal glands. Immunohistochemistry confirmed PPARgamma expression in approximately one-half of analysed samples. The intra- and intergroup differences observed in pituitary adenomas may represent new elements in the process of understanding the different clinical responses of Cushing's and Nelson patients to PPARgamma-ligand treatment. Moreover, the higher level of PPARgamma expression detected in the NFPA subgroup may suggest its possible role as a molecular target in these pituitary adenomas, paving the way for investigations on the effectiveness of treatment with thiazolidinediones in such patients.

The usefulness of combined biochemical tests in the diagnosis of Cushing's disease with negative pituitary magnetic resonance imaging.

OBJECTIVE: The etiological diagnosis of ACTH-dependent Cushing's syndrome is often a problem. In fact, no endocrine or radiological examination can conclusively distinguish the ectopic from the pituitary source of disease. The aim of our study was to evaluate the role of stimulation and suppression endocrine tests in the diagnostic and therapeutic approach of patients with Cushing's disease (CD) and negative pituitary magnetic resonance imaging (MRI), considering their post-surgical outcome in comparison with patients with CD and positive MRI. PATIENTS AND METHODS: We retrospectively analyzed 31 patients (25 women and 6 men, median age 40 +/- 15 years) with a confirmed diagnosis of CD who underwent transsphenoidal pituitary surgery by the same neurosurgeon between 2001 and 2005. Preoperative endocrine assessment included corticotropin-releasing hormone (CRH), desmopressin (dDAVP), and overnight 8 mg dexamethasone suppression tests (8-DST) in all patients. Fifteen patients had a normal pituitary MRI and sixteen had a clearly evident pituitary microadenoma. Bilateral inferior petrosal sinus sampling (BIPSS) was performed in patients with discordant biochemical results or with signs and symptoms highly suggestive of an ectopic source of ACTH. Post-surgical median follow-up was 38.4 +/- 22.0 months. RESULTS: Among patients with negative MRI, 60% had concordant positive endocrine tests and underwent neurosurgery without other examinations. BIPSS was performed in three other patients prompted by discordant endocrine tests (negative dDAVP) and in two patients with clinical suspicion of ectopic disease. Among patients with positive MRI, 87% underwent neurosurgery without BIPSS that was performed in two patients because of negative concomitant response to dDAVP and CRH tests. A pituitary adenoma, confirmed by pathological examination, was found in 40 and 81% of patients with negative and positive MRI respectively (P<0.05), corticotroph hyperplasia resulted more frequent in the group with negative MRI. Remission rate was not different between patients with negative and positive MRI (73 and 75% respectively; P=0.61) and between patients with negative MRI who did not undergo BIPSS and patients with positive MRI (P=0.56). The recurrence rate was also similar between groups (P=0.64), but higher, although not statistically different (P=0.07) in patients with corticotroph hyperplasia at histology. CONCLUSIONS: An accurate evaluation of presurgical endocrine tests results enabled us to reduce the number of BIPSS in patients with a negative MRI without any fallout on their post-surgical outcome. In the hands of an expert pituitary surgeon, the outcome after surgeryand the subsequent recurrence rate are much the same in patients with negative or positive MRI.

Characterization of C14orf4, a novel intronless human gene containing a polyglutamine repeat, mapped to the ARVD1 critical region.

Within the ARVD1 (arrhythmogenic right ventricular dysplasia/cardiomyopathy, type 1) critical region, mapped to 14q24.3, we detected an intronless gene of 4859 bp, predominantly expressed in the heart tissue. This gene encodes a 796-amino-acid, proline-rich protein showing polyglutamine and polyalanine tracks with variable length at the N-terminus and a C3HC4 RING finger domain at the C-terminus. CREB and AP-2 binding sites are present in the promoter region. The 5' flanking region contains neither a TATA box nor a CAAT box, but it is high in GC content and includes several Sp1 binding sites. Protein similarity searches revealed a significant match between the C-terminus and a human hypothetical protein, whose gene is located on the chromosome 19 long arm. The predicted protein shows PEST sequences, suggesting its rapid degradation. The novel intronless gene, provisionally named C14orf4 and probably encoding a nuclear protein, was excluded from being the ARVD1 gene.

Prognostic usefulness of dobutamine-induced ST-segment elevation and T-wave normalization after uncomplicated acute myocardial infarction.

We followed 229 consecutive patients exhibiting negative T waves on infarct-related electrocardiographic leads; these patients underwent dobutamine stress echocardiography within 10 days after a first uncomplicated acute myocardial infarction. T-wave normalization, but not ST-segment elevation, recognized patients at higher risk of cardiac events and optimized the prognostic accuracy of both myocardial viability and ischemia, to which it was correlated and became an independent predictor in cases of subdiagnostic stress echocardiography.

Dobutamine-induced T wave positivization after uncomplicated myocardial infarction: a marker of myocardial viability and higher cardiac risk.

BACKGROUND: There is evidence that after uncomplicated acute myocardial infarction, T wave positivization during stress testing may unveil myocardial viability. We evaluated in a prospective study the clinical value of T wave positivization during dobutamine stress echocardiography in patients with recent, first uncomplicated acute myocardial infarction. METHODS: Two hundred twenty-nine patients, who underwent dobutamine stress echocardiography within 10 days of uncomplicated acute myocardial infarction, were selected for exhibiting negative T waves in the infarct area. A mean follow-up of 2.1 +/- 1 years (up to 6 years) was obtained. RESULTS: T wave positivization appeared during dobutamine test in 76 (33%) patients. The agreement of T wave positivization for myocardial viability was 65% (95% confidence interval 59-71). Compared to myocardial viability during dobutamine stress echocardiography, the combination with T wave positivization was more sensitive (55 vs 24%, 95% confidence interval 46-64 vs 17-33) for predicting cardiac events, albeit less specific. Kaplan-Meier survival curves showed 47 (62%) cardiac events in patients with T wave positivization and 70 (46%) cardiac events in the remaining patients (p < 0.05). Soft (n = 91) prevailed over hard (n = 26) cardiac events. CONCLUSIONS: T wave positivization during dobutamine stress echocardiography after uncomplicated acute myocardial infarction identifies patients at higher cardiac risk, and is more sensitive, albeit less specific, for cardiac events than viability alone. T wave positivization is helpful in the case of inconclusive stress echocardiography. The pathophysiology of T wave positivization and its relative value among other variables warrant further analysis.

Early assessment of viable myocardium after acute myocardial infarction by low-dose echo-dobutamine.

BACKGROUND: The aim of the study was to evaluate the usefulness of low-dose dobutamine echocardiographic testing performed within 48 hours from anterior AMI in order to identify the extent of viable myocardium and predict its functional outcome. The early echo-dobutamine test was also compared with a predischarge test in order to evaluate the effects of different timing on the accuracy of the test. METHODS: Nineteen consecutive patients, aged 54 +/- 11 years, with a first anterior AMI entered the study. All patients underwent a low-dose dobutamine echocardiographic test within 48 hours from hospital admission and at predischarge. In all the patients, a rest follow-up echocardiogram was performed three months after hospital discharge. Eleven patients underwent a revascularization procedure (7 underwent PTCA and 4 CABG). RESULTS: Of the 159 dyssynergic segments, 26% improved spontaneously at predischarge and 51% improved at the three-month follow-up. Of the 145 predischarge dyssynergic segments, 38% improved at three months. Considering the results on a segmental basis, early low-dose dobutamine echocardiography showed a sensitivity of 52%, a specificity of 87%, a positive predictive value of 81%, a negative predictive value of 64% and a diagnostic accuracy of 69% for wall-motion improvement at three months. The predischarge test showed very similar values. A slight enhancement of the sensitivity of both tests was observed considering the akinetic segments only. Finally, considering the amount of segmental reversible dysfunction inside the infarct area in the single patients, early low-dose dobutamine echocardiography showed a sensitivity of 86% and a specificity of 80%. CONCLUSIONS: Our results indicate that: 1) recovery of regional wall motion after AMI is slow and progressive, with substantial improvement ensuing within the first days after infarction; 2) considering results on a segmental basis, low-dose dobutamine echocardiography performed within 48 hours of AMI shows a high specificity but a low sensitivity for late recovery of regional function, although it gave information similar to what was obtained performing the test at predischarge; 3) the efficiency of test can be improved by considering the amount of reversible segmental dysfunction inside the infarct area in the single patients.

Multicenter trial on prognostic value of inducible ischemia, assessed by dobutamine stress echocardiography and exercise electrocardiography test, in patients with uncomplicated myocardial infarction, treated with thrombolytic therapy.

BACKGROUND: Thrombolysis has reduced early and longterm mortality by about 20%; sometimes, however, there is a re-occlusion of the infarct related artery or an unsuccessful thrombolysis. In these situations, there is a possible increase in detrimental events in the follow-up. OBJECTIVES: The aim of the study was to compare the prognostic value of dobutamine echocardiography (DET) and ECG exercise test (EET) in pts submitted to thrombolysis. METHODS: One hundred and fifty-one pts, with acute uncomplicated myocardial infarction, were enrolled. The pts were able to perform EET and had a sufficient echocardiographic window; 58 had anterior myocardial infarction (38%), 79 had inferior (52%), 2 had lateral (1%), 12 had non-Q (8%). EET was performed with an initial load of 25 Watt, and thereafter, 25 W every two minutes. DET was performed with step-wise infusion every three minutes (5, 10, 20, 30 and 40 mcg/kg/min.). If the target heart rate was not reached, a further dose of 40 mcg/kg/min. together with atropine 0.25-1 mg was administered, in the absence of signs and symptoms of ischemia. RESULTS: During a mean (+/- SD) follow-up period of 8 +/- 4.5 months (range 1-23), 16 spontaneous events happened (4 deaths, 5 non-fatal re-infarctions, 7 unstable angina). One-hundred and three EET (68%) were negative for ongoing ischaemia, while 48 were positive, 79 DET (52%) were negative for ongoing ischaemia and 72 were positive (48%). Statistical results: DET and EET had a sensitivity of 41% and 54%, a specificity of 57% and 74%, a positive predictive value of 7% and 14%, a negative predictive value of 91% and 95%, an accuracy of 56% and 73%. Kaplan-Maier survival curves demonstrated that patients with Peak Wall motion > 1.8 and EET score > 3, had the higher risk of spontaneous events. CONCLUSION: A few spontaneous events happened in the follow-up. These data demonstrate that patients treated with thrombolysis are not at high risk of spontaneous events. DET and EET, therefore, have had a high negative predictive value. For this reason, we can conclude that pts with negative tests can be considered at low risk and do not need any further investigations.