Coordinate expression of beta-galactoside alpha 2,6-sialyltransferase mRNA and enzyme activity in suckling rat jejunum cultured in different media: transcriptional induction by dexamethasone.

In attempting to elucidate the molecular basis of the expression of alpha 2,6-sialyltransferase (alpha 2,6-ST) in jejunal explants of 7-day-old rats during cultivation, the total jejunal RNA was analysed by hybridization using a cDNA clone encoding rat liver alpha 2,6-ST. Under cultivation in both serum-free and serum-containing media jejunal alpha 2,6-ST mRNA closely paralleled the bound (100,000 g pellet) as well as the soluble (100,000 g supernatant) alpha 2,6-ST activity, the correlation coefficients being 0.976 and 0.

Adrenergic control of induction of type II iodothyronine 5'-deiodinase activity in cultured mouse brown adipocytes.

Iodothyronine 5'-deiodinase (5'D) of mouse brown adipocytes differentiated in cell culture was characterized in detail with respect to the adrenergic control of its biosynthesis. The stimulation of 5'D required mRNA and protein synthesis and was dependent on the stage of differentiation of the cells. The maximum induction was observed around confluence (7-day-old cells), in pre- and post-confluent cells the 5'D activity was significantly less induced.

Accumulation of boron-10 (10B) in cell cultures exposed to mercaptododecaborate (Na2H(11)10B12SH) used for the neutron capture therapy of brain tumors.

Toxicity of mercaptoundecahydro-closo-dodecaborate (MHB, Na2H(11)10B12SH) and accumulation of MHB-derived 10B were studied in E7 neuroblastoma, C6 glioma, HeLa cells and embryonic lung LEP 19 fibroblasts in culture in exponential and stationary phases of growth (2- and 7-day-old cultures, respectively). The pilot study of acute toxicity, performed on C6 glioma cells, showed good tolerance of the drug up to 1000 micrograms/ml (4.8 x 10(-3) M), when cell growth slowed and a small part of the population was lethally damaged (8.