Studies of dehydroepiandrosterone (DHEA) with the human estrogen receptor in yeast.

Dehydroepiandrosterone (DHEA) is a C19 adrenal steroid synthesized in the human adrenal cortex and serving as a biosynthetic precursor to testosterone and 17beta-estradiol. Despite the fact that it is one of the most abundant steroid hormones in circulation, the physiological role of DHEA in humans remains unclear. The action of DHEA itself, such as its interactions with receptors and nuclear transcription factors, is not well understood, and a specific DHEA receptor has yet to be identified. Although the activity of DHEA can be due to its metabolism into androgens and estrogens, DHEA has been shown to interact with the androgen receptor and the estrogen receptor (ER) in vitro. We demonstrate in this study that DHEA (3beta-Hydroxy-5alpha-androstan-17-one) inhibits 17beta-estradiol (E2) binding to its receptor in vivo in yeast. DHEA stimulates human ER dimerization in yeast, as determined by ER fusion protein interactions, GAL4 reconstitution and subsequent measurement of increased beta-galactosidase activity. DHEA causes an increase in estrogen response element-dependent beta-galactosidase activity, demonstrating that the ER dimer induced by DHEA is transcriptionally active, but at a concentration of DHEA about 1000 times greater than E2. Inclusion of the nuclear receptor co-activator RIP140 in the yeast enhances ER transactivation by DHEA or E2 in a ligand-dependent manner; moreover, only in the presence of RIP140 is DHEA able to stimulate beta-galactosidase activity to levels similar to those achieved by E2. Ligand-receptor interaction for other C19-steroids was also examined. While 5-androstene-3beta, 17beta-diol (ADIOL) displayed estrogenic activity in this system, 4-androstene-17-dione (androstenedione) and 4-androstene-17beta-ol,3-one (testosterone) did not. We have investigated whether DHEA can interact with the human ER in vivo. Our findings demonstrate a mechanism by which DHEA interacts directly with estrogen signaling systems; however, because DHEA is several orders of magnitude less potent than E2 in this system, we conclude that it essentially is not an estrogen agonist.

Utility of transvenous liver biopsies and wedged hepatic venous pressure measurements in sixty marrow transplant recipients.

Sixty marrow transplant recipients with liver dysfunction underwent transvenous liver biopsy and measurement of the hepatic venous pressure gradient. Biopsies were done on 29 patients using a Cook needle inserted through the jugular vein, on 30 patients through the femoral vein with a Mansfield biopsy forceps, and on 1 patient using both instruments. The average number of evaluable portal spaces was 4.0 for aggregated Cook needle specimens and 5.2 for Mansfield forceps specimens. The average number of central venules was 2.6 for Cook needle specimens and 3.5 for Mansfield specimens. Tissue obtained with the Mansfield forceps had crush artifact, especially along the edges, making assessment of bile ducts more difficult than in Cook needle specimens. Liver histology aided management in 53/60 patients by confirming the clinical diagnosis in 24 (40%) and by providing additional diagnoses in 29 (48%). Hepatic venous pressure gradient > 10 mmHg correlated with a histologic diagnosis of veno-occlusive disease (P = 0.001); this gradient value provided 91% specificity and 86% positive predictive value. Eleven patients had bleeding complications, 9 after Cook needle biopsy and 2 after Mansfield forceps biopsy. There were 3 procedure-related deaths, 2 from intraperitoneal bleeding after Cook needle biopsy and 1 from femoral vein bleeding after Mansfield biopsy. We conclude that transvenous liver biopsy and pressure measurements provide useful diagnostic information in marrow transplant patients with liver disease. In our hands, the Mansfield forceps was associated with a lower risk of intra-abdominal bleeding and capsular perforation of the liver while providing adequate histology for diagnosis. Hepatic venous pressure gradients > 10 mmHg were highly specific for a diagnosis of veno-occlusive disease in this patient population.

Coagulopathy associated with hematin treatment for acute intermittent porphyria.

Hematin has been shown to be effective therapy for acute intermittent porphyria. Few complications have been found. We cared for a patient who developed a markedly prolonged prothrombin time, partial thromboplastin time, thrombocytopenia, mild hypofibrinogenemia, mild elevation of fibrin split products, and a 10% fall in hematocrit while receiving hematin. No other cause for the coagulopathy could be found. The abnormal coagulation variables returned to normal when hematin was discontinued. Patients receiving hematin for acute intermittent porphyria should be closely observed for signs of coagulopathy.