Heterocyclic derivatives based on N6-substituted adenine of, e. In some embodiments, an electrical stimulator may be used to stimulate a patient’s heart to reduce ventricle filling volume or even blood pressure. , alkyl radicals having 1 to 4 carbons, and alkylcarbonyl radicals having 1 to 4 carbons; and about 50 to about 95 wt % of solvent comprising about 10 to about 90 wt % of a lower aliphatic alcohol and about 10 to about 90 wt % of water. The seal carrier has an axial inflow bore connected to a fluid high-pressure source and at least one transverse bore branching off from the axial inflow bore. A first end of the shroud compresses a packing seal to form a liquid impermeable seal with each passageway and with the outer surface of the electrical cable.