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Biomedical subjects

L Nieman

Publications and source records attributed to L Nieman.

29 records · Page 2Linked to original sources
PubMed1990

Management of the ectopic ACTH syndrome due to thoracic carcinoids.

The association of a bronchial or thymic carcinoid as a source for the ectopic production of adrenocorticotropic hormone (ACTH) has been reported since 1957, with approximately 72 cases in the literature. These patients are characterized by young age, long duration of Cushing's syndrome because of the inability to find the ectopic source, and a high incidence of hypophysectomy or adrenalectomy without curing the disease. A substantial number of patients, upon discovery of the thoracic ectopic source, are also found to have malignant carcinoid tumors with lymph node metastases. Fifteen patients have been explored for a presumed intrathoracic source of ACTH at our institution since 1983 and 14 carcinoids (13 bronchial, one thymic) have been resected. Seventy-one percent (10/14) of the patients appear cured with normal plasma ACTH levels 5 to 57 months after resection, despite a 50% incidence of positive lymph node disease. Management of these patients demands an aggressive evaluation to prevent unnecessary adrenalectomy or hypophysectomy and to allow earlier resections before these potentially curable malignancies metastasize. When the tumor is discovered, thorough exploration and complete lymph node mapping with resection must be performed.

ACTH Syndrome, Ectopic↗
PubMed1990

Pituitary microadenomas: a PET study.

Twenty cases of surgically verified pituitary microadenoma (17 with Cushing disease and three with acromegaly) were studied with positron emission tomography (PET) with use of fluorine-18-2-fluorodeoxyglucose (FDG). The diagnostic results were compared with those of other modalities, namely, computed tomography (CT), magnetic resonance (MR) imaging, and, in the cases of Cushing disease, simultaneous bilateral inferior petrosal sinus sampling (SIPS). The PET results showed 12 positive readings and one questionable reading, compared with seven positive readings and one questionable reading for CT (18 cases studied) and 13 positive and two questionable MR imaging readings. PET complemented MR imaging, in the sense that five of the positive PET readings were negative or questionable at MR imaging. PET studies of 20 healthy control subjects showed no false-positive cases, whereas other studies of healthy subjects with contrast material-enhanced CT and MR imaging have yielded, respectively, 20% and 15% positive readings, with findings suggestive of silent or occult adenomas.

Adenoma↗
PubMed1989

RU-486 inhibits rat gonadal steroidogenesis.

RU-486 is a synthetic steroid analogue that can inhibit adrenal steroid synthesis in the rat and rhesus monkey. We measured the activities of five testicular and two ovarian microsomal steroidogenic enzymes to assess the potential effect of RU-486 on rat gonadal steroidogenesis. Hypophysectomized, gonadotropin-replaced rats received RU-486 or a vehicle solution twice daily for seven days. The animals were sacrificed and their gonads were resected, weighed, and microsomal enzyme activities were measured according to RU-486 treatment. Testicular 17-hydroxylase and aromatase activity decreased in RU-486 treated animals whereas 17,20-desmolase, 3 beta-hydroxysteroid dehydrogenase and 17-ketosteroid reductase activities were unaffected. Ovarian 17-hydroxylase but not 3 beta-hydroxysteroid dehydrogenase activity was decreased in the animals receiving the drug. We conclude that RU-486 inhibits both testicular and ovarian steroidogenesis in the rat.

17-Hydroxysteroid Dehydrogenases↗
PubMed1989

Ectopic adrenocorticotropic hormone syndrome: localization studies in 28 patients.

A variety of imaging procedures were performed in 28 patients with ectopic adrenocorticotropic hormone (ACTH) syndrome in an attempt to localize the ACTH-producing tumor. Diagnosis was made on the basis of removal of an ACTH-producing tumor or biopsy of metastases in the 19 patients with a proved source and the absence of ACTH gradients in bilateral samples of the inferior petrosal sinuses in the nine patients in whom an ACTH-secreting tumor had not been localized. Eleven bronchial carcinoids, two thymic carcinoids, three pheochromocytomas, and three islet-cell tumors constituted the proved sources. The condition has been cured in eight patients, six are alive with residual tumor, and five have died. Of the nine patients with undetected sites of ACTH production, one has died of pneumocystis pneumonia and eight are being treated medically or with bilateral adrenalectomy. Computed tomography (CT) of the chest and abdomen was the most helpful study in the detection of these tumors. Selective arteriography (bronchial and visceral), systemic and portal venous sampling, and iodine-131 meta-iodobenzylguanidine scintigraphy failed to demonstrate tumors when findings at CT were negative. Bronchial carcinoids constituted most of the ACTH-secreting tumors in this study (58%) and in a review of four large series (47%). To assure early detection of these potentially malignant tumors, pulmonary CT should be performed every 6 months, even after hypercortisolism has been medically or surgically controlled.

ACTH Syndrome, Ectopic↗
PubMed1989

Cushing syndrome due to primary pigmented nodular adrenocortical disease: findings at CT and MR imaging.

Primary pigmented nodular adrenocortical disease (PPNAD) is a rare cause of Cushing syndrome in infants, children, and young adults. It is characterized by non-adrenocorticotropic hormone-dependent hypersecretion of cortisol by multiple, pigmented nodules of hyperplastic adrenocortical cells. With a single exception, adrenal glands have been described as normal with computed tomography (CT) in all previous series. Eight patients had Cushing syndrome due to surgically proved PPNAD. Four of the eight patients had stigmas of Carney complex (lentigines, calcified Sertoli cell tumors of the testes, and cardiac and soft-tissue myxomas). CT and/or magnetic resonance (MR) imaging demonstrated unilateral or bilateral nodularity in five of six patients examined. Macronodules (greater than 10 mm) were seen in the two oldest patients. As the clinical presentation of Cushing syndrome in this group of patients may be atypical (severe osteoporosis or short stature), the detection of multiple, small adrenocortical nodules with CT or MR imaging supports, or may even suggest, the diagnosis of PPNAD.

Adolescent↗
PubMed1989

Failure of bronchial lavage to detect elevated levels of adrenocorticotropin (ACTH) in patients with ACTH-producing bronchial carcinoids.

Saline lavage of the major bronchial segments was performed in five patients immediately preceding lobectomy to remove an ACTH-producing bronchial carcinoid. Lavage fluid from each bronchus was concentrated, and ACTH determinations were performed. Elevated concentrations of ACTH were not demonstrated in the aspirate from the bronchus containing the known tumor. Two additional patients with ectopic ACTH syndrome from an unknown primary source also underwent selective segmental bronchial lavage for ACTH determination. Neither patient demonstrated ACTH gradients in the lavage specimens. One was found to have an ACTH-producing bronchial carcinoid 18 months after negative lavage. Selective segmental bronchoscopic lavage with measurement of ACTH levels on the aspirate is not an effective technique for detecting ACTH-producing bronchial carcinoid tumor.

Adrenocorticotropic Hormone↗
PubMed1989

Primary pigmented nodular adrenocortical disease. A light and electron microscopic study of eight cases.

Primary pigmented nodular adrenocortical disease (PPNAD) is a rare cause of Cushing's syndrome, which is adrenocorticotropic hormone-independent and involves both adrenal glands. The characteristic pathological features include multiple pigmented cortical nodules and atrophy of the internodular cortex. The adrenal size ranges from small to normal or slightly enlarged. Review of the gross, light microscopic, and ultrastructural features of eight cases seen at the National Institutes of Health revealed several very unusual findings. We observed the following in our patients: macronodules up to 3.0 cm; microscopic foci of necrosis; mitoses; cortical hyperplasia rather than internodular atrophy; focal confluence of nodules giving a diffuse pattern of cortical involvement, and a focal trabecular growth pattern. The nodules were composed primarily of eosinophilic, lipid-poor cells similar to those of the zona reticularis. However, lipid-rich cells similar to those of the zona fasciculata were also demonstrated in the nodules by both light and electron microscopy. This suggests that the adrenal cortical nodules of PPNAD may be derived from not only the zona reticularis, but also the zona fasciculata.

Adolescent↗
PubMed1988

Macronodular adrenal hyperplasia in Cushing disease.

Computed tomographic (CT) scans of the adrenal glands were obtained in nine patients with Cushing disease as a result of an adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma and macronodular hyperplasia of the adrenal glands. The findings were compared retrospectively with those in six patients with Cushing syndrome as a result of an autonomous adrenal adenoma and 16 with Cushing syndrome as a result of ectopic ACTH production. Seven of nine patients with macronodular adrenal hyperplasia had hyperplastic adrenal glands in addition to single or multiple focal adrenal nodules. The six patients with hypercortisolism caused by an autonomous adrenal adenoma showed atrophic (four patients) or normal (two patients) ipsilateral and contralateral adrenal glands. Fourteen of 16 patients with the ectopic ACTH syndrome had hyperplasia of the adrenal glands without nodularity, and only two had focal nodules.

ACTH Syndrome, Ectopic↗
PubMed1988

The antiglucocorticoid and antiprogestin steroid RU 486 suppresses the adrenocorticotropin response to ovine corticotropin releasing hormone in man.

The glucocorticoid and progesterone antagonist RU 486 normalizes the clinical and biochemical features of hypercortisolism in patients with nonpituitary Cushing's syndrome, presumably by antagonizing the action(s) of cortisol. Since RU 486 has progesterone agonist activity in addition to its progesterone antagonist action, the possibility that it might have some glucocorticoid agonist action did not seem unreasonable. To test this hypothesis we examined the effects of RU 486 on pituitary ACTH secretion in 10 patients with primary adrenal insufficiency in whom glucocorticoid replacement was withheld for 36 h. Each patient received, in randomized sequence 3-7 days apart, an oral dose of placebo, RU 486 (20 mg/kg), cortisol (0.1 mg/kg), or a combination of RU 486 and cortisol at 1800 h. Two hours later, an iv bolus dose of ovine CRH (1 microgram/kg) was administered, and plasma ACTH levels were measured serially for 3 h. RU 486 suppressed ovine CRH-stimulated ACTH secretion, albeit less than cortisol. Its glucocorticoid agonist effect was calculated to be approximately 1/250th that of cortisol on a weight basis. Additionally, RU 486 partially antagonized cortisol-induced suppression of ACTH secretion. These findings suggest that RU 486 is a partial glucocorticoid agonist and offer some insight as to its action in patients with Cushing's syndrome. Whether this degree of glucocorticoid agonist activity is adequate to support life, however, is not known.

Addison Disease↗
PubMed1986

Rebound thymic hyperplasia after treatment of Cushing's syndrome.

Rebound thymic hyperplasia has been described in children and young adults after recovery from stress. Similar thymic enlargement has been observed in patients after remission of Cushing's syndrome. In one patient successfully treated for ectopic adrenocorticotropic hormone (ACTH) syndrome by resection of a bronchial carcinoid with a hilar metastasis, the postoperative enlarging mediastinal mass suggested recurrent tumor. In another patient treated for an undetected ectopic ACTH source by a cortisol antagonist, the enlarging thymus could be confused with a thymic carcinoid. The typical thymic appearance on CT and the chronologic relation to declining cortisol levels should prevent such diagnostic errors.

ACTH Syndrome, Ectopic↗