RESUMO
OBJECTIVE: To assess the utility of the desmopressin (DDAVP) test in the diagnosis and follow-up of a cyclical Cushing's disease (CCS) case. MATERIAL AND METHODS: Laboratory tests included morning and midnight serum cortisol levels, 24h urine free cortisol excretion, midnight salivary cortisol levels, serum cortisol levels after low (1 mg) and high (8 mg) dexamethasone, plasma ACTH and serum cortisol levels after DDAVP. Magnetic resonance imaging (MRI) was used to assess the presence of a pituitary adenoma. The resected tumor specimen was studied by histological, immunohistochemical and cell biology techniques. RESULTS: A patient was referred to our unit with a diagnosis of Cushing's syndrome (CS) for further evaluation and treatment. However, no biochemical evidence of hypercortisolism was observed in the follow-up evaluations. Furthermore, the typical features of CS fluctuated throughout this period. A consistent positive response to the DDAVP stimulation test was observed during the diagnostic work-up, even when overt clinical features of CS were not apparent, raising suspicion for CCS. After two years of follow-up a definitive diagnosis of hypercortisolism was established. An MRI scan revealed a pituitary adenoma, as the source of ACTH production. After transphenoidal surgery, clinical signs of CS resolved and the response to DDAVP became negative. DDAVP induced a significant increase in ACTH levels in cultured pituitary adenoma cells, consistent with the in vivo DDAVP test results. CONCLUSIONS: Our case illustrates the utility of the DDAVP test in the evaluation of patients with suspected CCS. The DDAVP test could facilitate the management of CCS by shortening the time of diagnosis.
Assuntos
Adenoma Hipofisário Secretor de ACT/complicações , Desamino Arginina Vasopressina , Periodicidade , Hipersecreção Hipofisária de ACTH/diagnóstico , Neoplasias Hipofisárias/complicações , Adenoma Hipofisário Secretor de ACT/diagnóstico , Adenoma Hipofisário Secretor de ACT/genética , Adenoma Hipofisário Secretor de ACT/cirurgia , Hormônio Adrenocorticotrópico/metabolismo , Adulto , Ritmo Circadiano , Desamino Arginina Vasopressina/farmacologia , Feminino , Humanos , Hidrocortisona/análise , Hidrocortisona/metabolismo , Hipofisectomia , Imageamento por Ressonância Magnética , Fenótipo , Hipersecreção Hipofisária de ACTH/sangue , Hipersecreção Hipofisária de ACTH/etiologia , Hipersecreção Hipofisária de ACTH/urina , Neoplasias Hipofisárias/diagnóstico , Neoplasias Hipofisárias/genética , Neoplasias Hipofisárias/cirurgia , RNA Mensageiro/genética , RNA Mensageiro/isolamento & purificação , RNA Neoplásico/genética , RNA Neoplásico/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células Tumorais CultivadasRESUMO
Se amplificó al azar el ADN de 10 individuos de 5 poblaciones de Rivulus colectados en la región occidental de Cuba. De la amplificación, empleando 5 cebadores, no resultó ningún marcador monomórfico, lo que evidenció una alta variabilidad genética entre los peces de las 5 poblaciones. Según la distancia genética entre los individuos, se forman 4 grupos, para cada uno de los cuales aparecen marcadores genéticos de RAPD (ADN polimórfico amplificado al azar) que son específicos, porque no se evidencian en el resto de los individuos. Estos resultados apoyan la utilización del RAPD como una herramienta eficiente para la caracterización genética de peces cubanos del género Rivulus.
DNA from 10 individuals from 5 populations of Rivulus collected in the western region of Cuba was amplified at random. No monomorphic marker resulted from the amplification by using 5 primers, which showed the high genetic variability existing among the fishes of the 5 populations. According to the genetic distance among the individuals, they were divided into 4 groups, for which there are specific genetic markers of RAPD, since they are not observed in the rest of the subjects. These results support the use of RAPD as an efficient tool for the genetic characterization of Cuban fishes of the Rivulus genus.