Maintenance of cell proliferation and steroidogenesis in cultured human fetal adrenal cells chronically exposed to adrenocorticotropic hormone: rationalization of in vitro and in vivo findings

Previous studies indicated that acute exposure of adrenal cells to adrenocorticotropic hormone (ACTH) markedly stimulates steroidogenic capacity in vitro but also inhibits cell proliferation. However, in vivo, ACTH is known to stimulate adrenal cell growth. To address this discrepancy, we determined the effect of long-term (9-11 days) continuous or intermittent exposure to ACTH on human fetal adrenal cell proliferation and steroidogenesis. Adrenal glands from fetuses 18-22 wk gestation were studied. Fetal zone cells were plated either on plastic or on an extracellular matrix (ECM) in the presence and absence of basic fibroblast growth factor (bFGF) (0.5 ng/ml) and 1 or 10 nM ACTH. As determined by cell counting, bFGF stimulated cell proliferation during 9 days in culture. In the presence of bFGF, the average doubling time decreased from 44 to 30 h on plastic and from 37 to 26 h on ECM. Under these conditions, ACTH did not inhibit cell proliferation. Proliferation of fetal adrenal corticosteroid-producing cells in the ACTH-treated cultures also was assessed by histochemical staining for 3 beta-hydroxysteroid dehydrogenase (3 beta HSD). The number of positive cells increased more than 4-fold between Days 5 and 9 in culture. Continuous treatment with 1 nM ACTH increased dehydroepiandrosterone sulfate (DHAS) production 5- to 10-fold during the first 5 days in culture. Thereafter, the stimulated hormone production decreased over time, although there was still a difference of almost 100-fold between the control and ACTH-treated cultures at the end of 9 days.(ABSTRACT TRUNCATED AT 250 WORDS)     

Asymmetric reduction of ketones with resting cells of Sulfolobus solfataricus

The method of resting cells has been of interest in the development of biocatalysts applied to organic reactions.This article deals with the use of resting cells of a thermophilic archaebacterium Sulfolobus solfataricus, in the asymmetric reduction of acyclic, cyclic, and aromatic ketones. The system allows the continuous regeneration of endogenous coenzyme with the coupled substrate approach. The results indicate that the direction of hydride attack was equatorial on the re face of the carbonyl group of substrates producing (S)-alcohols with a good optical yield. A convenient system for the reuse of resting cells has been set out to synthesize (S)-alcohols on a preparative scale.     

Comparison of two methods for measuring human serum immunoglobulins (laser-nephelometry and radial immunodiffusion)

The AA. have tested 50 serum samples for immunoglobulins (IgG, IgA, IgM) with two different methods: laser-nephelometry (LN) and radial immunodiffusion (RID). Mean values of IgG and IgA are almost the same in the two tested methods and there is a good correlation between LN and RID (IgG: r = 0,98; IgA: = 0,96). Also IgM have showed a good correlation (r = 0,987) but mean values obtained with LN are just a few lower than those obtained with RID. Regression lines, calculated for all the Ig, confirm these conclusions. The AA. conclude affirming that the obtained difference for IgM is due to the different standards used for LN and RID determinations.     

Structural regularities in tetraether lipids of Caldariella and their biosynthetic and phyletic implications

Individual di(biphytanyl) diglycerol tetraether lipids from thermoacidophile archaebacteria of the Caldariella series, with differently cyclized biphytanyl components, are separated and shown to have structures 8–12, with the glycerol and biphytanyl components demonstrably both antiparallel and with partial assignments of stereochemistry. Tetraethers with alternative arrangements of the components are absent. The structures allow previous observations on these and related lipids to be rationalized both biosynthetically and phyletically.     

NADH-coupled spectrophotometric assay of tyrosine aminotransferase

A rapid spectrophotometric method for estimation of tyrosine aminotransferase activity (TAT) is described, based on a coupled reaction with NADH-dependent aromatic ketoacid reductase. 3-iodo-L-tyrosine, upon TAT action, is transformed into 3-iodo-4-hydroxyphenylpyruvate which quickly reacts with NADH in the presence of aromatic ketoacid reductase; oxidation rates at 340 nm are linear with protein concentration over the whole range of purification steps of TAT. This new method, for its sensitivity, easy performance and possibility of a continuous monitoring of TAT reaction, may be considered comparable to the more diffuse spectrophotometric standard method, and also as an alternative, advantageous procedure in some instances. The method for purification of the coupled aromatic ketoacid reductase is also described.     

Uptake and Elimination of Poliovirus by West Coast Oysters

Accumulation of poliovirus Lsc-2ab by West Coast oysters was determined by using a stationary seawater system, and depuration was determined by using both stationary and free-flow systems. Results indicate that these shellfish have the same pattern of accumulation and localization of viruses as do East Coast species. However, uptake appeared to occur more rapidly than described for East Coast shellfish. There appeared to be a gradual diffusion of virus from the digestive area into the body. Depuration was found to occur more rapidly and completely under free-flow conditions than in a stationary system.