RESUMEN
In patients with Cushing's disease (CD), basal inferior petrosal sinus arginine vasopressin (AVP) concentrations are greater than peripheral levels and are further increased by the administration of CRH. AVP has an interpetrosal sinus gradient similar to that for ACTH, leading to the hypotheses that petrosal sinus AVP might either be derived from the corticotroph adenoma or be important for adenoma formation. To determine whether petrosal sinus AVP is truly increased in patients with CD, we compared inferior petrosal sinus and peripheral venous AVP and ACTH levels in 23 patients with CD and 9 healthy volunteers before and after iv ovine CRH. In both groups, AVP and ACTH showed interpetrosal lateralization, such that greater levels of both hormones were found at each time point in a single dominant petrosal sinus. When both hormones exhibited lateralization (an intersinus gradient > 1.5), ACTH and AVP always lateralized together. In patients with CD, the ACTH interpetrosal sinus lateralization correctly identified the side of the pituitary containing the tumor in 75% of evaluable patients, whereas the AVP interpetrosal sinus lateralization identified 63% (P = NS). Ovine CRH stimulated AVP in both the dominant and nondominant petrosal sinuses in patients with CD. Although basal AVP in the dominant petrosal sinus was not significantly different in patients with CD and normal volunteers (144 +/- 85 vs. 13.0 +/- 4.3 pmol/L; P = 0.058), dominant petrosal sinus AVP was significantly elevated in patients with CD compared to normal volunteers at 3 min (269 +/- 122 vs. 45.1 +/- 30.0 pmol/L; P < 0.05) and 5 min (315 +/- 120 vs 40.2 +/- 23.6 pmol/L; P < 0.05) after ovine CRH administration. Peripheral venous AVP levels were similar in all groups. We conclude that lateralization of AVP secretion occurs in both patients with CD and normal volunteers, but there is greater CRH-stimulated AVP secretion in the inferior petrosal sinuses of patients with CD.
Asunto(s)
Arginina Vasopresina/sangre , Síndrome de Cushing/sangre , Muestreo de Seno Petroso , Hormona Adrenocorticotrópica/sangre , Adulto , Anciano , Animales , Hormona Liberadora de Corticotropina , Femenino , Humanos , Masculino , Persona de Mediana Edad , Concentración Osmolar , Valores de Referencia , Ovinos , Distribución TisularRESUMEN
Sudden infant death syndrome is the term applied to the sudden death of an infant or young child that is unexpected by history and for which a thorough postmortem examination fails to demonstrate an adequate cause of death. It is widely believed that sudden infant death syndrome is not an expression of a single cause and effect, but rather a multifactorial phenomenon. This paper gives an overview of recent developments in sudden infant death syndrome research presenting the various hypotheses regarding sudden infant death. Functional disturbances in the brainstem and cervical spinal cord areas related to the neurophysiology of respiration may contribute to the clinical findings associated with sudden infant death syndrome. Parturitional factors, which include maternal (labor and delivery) and extrinsic factors (obstetrical procedures) have received attention. Work has also been done on the development of those neuroanatomical structures associated with respiration. It is postulated that human development progresses through stages with a critical period at 2-4 months. Immaturity of the brainstem and cervical cord is characterized, histologically, by the presence of reticular dendritic spines on the neurons as well as a proliferation of astrocytes and glial cells. Any process, whether genetic, biochemical, biomechanical or traumatic, that alters normal development of the respiratory control centers related to spinal constriction and compression following birth trauma may be contributory to sudden infant death syndrome.
Asunto(s)
Quiropráctica , Muerte Súbita del Lactante/etiología , Humanos , LactanteRESUMEN
A patient with recent inferior myocardial infarction with right ventricular involvement developed severe hypoxemia unresponsive to 100% oxygen. Contrast two-dimensional echocardiography revealed right to left shunting through an aneurysmal fossa ovalis with a patent foramen ovale. This was confirmed by cardiac catheterization. Surgical closure of the defect was probably life-saving. This case report illustrates that right to left shunting through a foramen ovale should be considered in the differential diagnosis of hypoxemia in patients presenting with inferior myocardial infarction.
Asunto(s)
Defectos del Tabique Interatrial/complicaciones , Hipoxia/etiología , Infarto del Miocardio/complicaciones , Anciano , Cateterismo Cardíaco , Femenino , Defectos del Tabique Interatrial/fisiopatología , Defectos del Tabique Interatrial/cirugía , Ventrículos Cardíacos/fisiopatología , Humanos , Hipoxia/fisiopatología , Hipoxia/cirugía , Infarto del Miocardio/fisiopatologíaRESUMEN
Cavitary pulmonary disease secondary to coccidioidomycosis occurs in endemic areas of the southwestern United States. Significant hemoptysis requiring pulmonary resection may develop in patients with cavitary lesions. In rare instances hemoptysis may be due to the development of a fungus ball within the cavity, and such mycetomas may contain spherule and mycelial forms of Coccidioides immitis. A patient with a documented coccidioidal cavity who had hemoptysis is described in this report. Chest radiograph revealed a fungus ball within a left lower lobe cavity. The patient underwent left lower lobectomy and recovered without complications. Examination of the resected left lower lobe disclosed a cavity containing a fungus ball comprised of mycelial and spherule forms of Coccidioides immitis. A review of the literature found three reports of biphasic growth of this condition within a coccidioidomycosis cavity and two additional cases of radiographically diagnosed coccidioidal mycetoma. Discussion of the potentially contagious nature, the medical and surgical management, and the prognosis of coccidioidal mycetoma form the basis of this report.