Collective and individual burial practices. Changing patterns at the beginning of the third millennium BC: The megalithic grave of Altendorf

The re-analyses of the Altendorf gallery grave reveal three different phases of inhumation burial practices: collective burials of a whole community (3250–3100 BC), a hiatus in burial practice (3100–2600 BC), and fewer but continuous single inhumations (2600–1450 BC). These changes can be associated with the abandonment of collective social practices all over Central Europe at the end of the fourth millennium BC, and the establishment of new ideologies and the re-use of older monuments by 2600 BC. In Altendorf, this last phase extends to the next pan-European change in burial practices, and reveals an enduring relationship with a local burial monument

Regulation of natriuretic peptide (urodilatin) release in a human kidney cell line

Regulation of natriuretic peptide (urodilatin) release in a human kidney cell line.BackgroundTo identify the molecular mechanisms underlying the release of a renal natriuretic peptide (NP) we selected a human kidney cell line (HEK 293) that displays several characteristics of distal tubular cells.MethodsCells were exposed to different extracellular and intracellular stimuli, and the effect on NP release was measured with a specific urodilatin radioimmunoassay, as well as with an atrial NP (ANP) radioimmunoassay.ResultsIn the absence of stimuli, HEK 293 cells showed a basal release of urodilatin immunoreactivity and ANP immunoreactivity. Raising the osmolality of the secretion medium with sodium chloride and various other osmolytes rapidly increased cellular NP secretion. Elevation of intracellular cAMP levels by forskolin plus 3-isobutyl-1-methylxanthine and administration of phorbol-12-myristate-13-acetate together with the calcium-ionophore A23187 also resulted in respective increases in the amount of secreted peptide. HEK 293 cells exhibit the endogenous expression of both particulate and soluble guanylyl cyclases. In the presence of 8-Br-cGMP, cell cultures showed the enhanced secretion of an ANP immunoreactive peptide only, indicating that guanylyl cyclase activation provoked the secretion of ANP immunoreactivity but not of urodilatin immunoreactivity.ConclusionsThe human embryonic kidney cell line HEK 293 represents a renal cellular model system in which we have identified a rapid and regulated release of NPs in response to the osmotic effect of increased extracellular sodium chloride and various intracellular stimuli