Lack of thyroid hormone receptor alpha1 is associated with selective alterations in behavior and hippocampal circuits.

Brain development and function are dependent on thyroid hormone (T3), which acts through nuclear hormone receptors. T3 receptors (TRs) are transcription factors that activate or suppress target gene expression in a hormone-dependent or -independent fashion. Two distinct genes, TRalpha and TRbeta, encode several receptor isoforms with specific functions defined in many tissues but not in the brain. Mutations in the TRbeta gene cause the syndrome of peripheral resistance to thyroid hormone; however, no alterations of the TRalpha gene have been described in humans. Here we demonstrate that mice lacking the TRalpha1 isoform display behavioral abnormalities of hippocampal origin, as shown by the open field and fear conditioning tests. In the open field test mutant mice revealed less exploratory behavior than wild-type mice. In the contextual fear conditioning test mutant mice showed a significantly higher freezing response than wild-type controls when tested 1 week after training. These findings correlated with fewer GABAergic terminals on the CA1 pyramidal neurons in the mutant mice. Our results indicate that TRalpha1 is involved in the regulation of hippocampal structure and function, and raise the possibility that deletions or mutations of this receptor isoform may lead to behavioral changes or even psychiatric syndromes in humans.

The diagnostic value of Tc-99m human polyclonal immunoglobulin imaging compared to Tc-99m HMPAO labeled leukocytes in inflammatory bowel disease.

The aim of this study was to establish the usefulness of Tc-99m human polyclonal immunoglobulin (HIG) imaging in a group of patients who were suspected of having inflammatory bowel disease (IBD). The authors performed 30 scans (15 with Tc-99m HMPAO leukocytes and 15 with Tc-99m HIG) on 15 patients with IBD. Ten patients had Crohn's disease and five had ulcerative colitis. The sensitivity of Tc-99m HIG scintigraphy for detecting IBD was 33%, while the sensitivity of Tc-99m HMPAO leukocyte imaging was 100%. The Tc-99m HMPAO leukocyte imaging also detected a larger number of affected segments and provided better image quality of the extent of disease than Tc-99m HIG. On the basis of these results, the authors believe that Tc-99m HIG imaging is not a useful technique in the evaluation of patients with IBD, in the identification of location, or the extension or degree of disease activity.

Efficacy of D-dimer and total fibrin degradation products evaluation in suspected pulmonary embolism.

Three different assays for fibrin/fibrinogen degradation products (FDP) were evaluated in patients with suspected pulmonary embolism (PE) as rapid screening tests with the aim of evaluating whether they could be used either as a substitute of ventilation/perfusion lung scanning or to supplement scintigraphy in patients in whom the scan was inconclusive (low or intermediate probability). D-Dimer by enzyme-linked immunosorbent assay (ELISA) and latex and total FDP by ELISA were measured prospectively in 85 consecutive patients with suspected PE. With a cutoff of 500 ng/ml, D-dimer by ELISA presented a 96% sensitivity and a 42% specificity, with positive and negative predictive values of 49 and 96%, respectively. D-Dimer by latex, also with a cutoff of 500 ng/ml showed a 93% sensitivity and 29% specificity, with positive and negative predictive values of 43 and 89%. For total FDP, with a cutoff of 900 ng/ml, the sensitivity and specificity were 96 and 26% respectively, with positive and negative predictive values of 42 and 93%. A normal assay may have reduced the necessity of a ventilation/perfusion only in 28% patients with D-dimer ELISA, 21% with D-dimer latex and 17% with total FDP ELISA and with a possible error of 4, 11 and 7%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

A case of complete Carney's syndrome.

The triad of gastric leiomyoblastoma, paraganglioma, and pulmonary chondroma was first described by Carney in 1977. The authors report a case of a patient with gastric leiomyosarcoma, multiple pulmonary chondromata, and paraganglioma. This represents a complete form of Carney's triad. The paraganglioma was identified with I-123 MIBG.

[Gammagraphic diagnosis of a non-hyperactive suprarenal adenoma]. / Diagnóstico gammagráfico de un adenoma suprarrenal no hiperfuncionante.

It is described the case of a patient with Ovarian Cystadenoma in whom a 3.5 cm nodular lesion was accidentally detected in her left suprarenal gland. She had no signs of hypercortisolism or any other suprarenal pathology and was symptomless. Determinations in the urine of 24 hours of Cortisol, Adrenaline and Noradrenaline, 17-ketosteroids and Tetrahydroaldosterone were normal. Daily rhythm and plasmatic determinations of ACTH, cortisol and 11-deoxycortisol were normal. The Dexamethasone suppression test was also normal. In the suprarenal gammagraphy it appeared an intense captation by left suprarenal without visualization of right gland. A left suprarenalectomy was performed and the anatomopathological analysis showed a clear cell corticoadrenal adenoma. Therefore the only data of the function of suprarenal adenoma was the one coming from gammagraphy. We thought that the adenoma was responsible of practically all the corticoadrenal function without reaching pathological levels, meeting the criteria of "pre-Cushing" syndrome or subclinical Cushing, due to the fact that the contralateral gland was not seen in the gammagraphy. Therefore in the characterization of certain tumors which appear clinically and biochemically as non functional, the suprarenal gammagraphy could be a technique of great usefulness for the diagnosis.