Adenylate cyclase activity in cultured epithelial cells.

The cyclic AMP metabolism of cultured epithelial cells was investigated. Epinephrine or 1-methyl,3-isobutylxanthine (MIX) alone had no effect on cyclic AMP levels in intact cells, whereas the combination of the two agents yielded a 6- to 10-fold increase in cyclic AMP levels. Both basal and stimulated cyclic AMP levels decreased with increasing cell density. Cell-free adenylate cyclase preparations were stimulated markedly by epinephrine or isoproterenol in the absence of MIX. Since the epithelial cells were found to have a relatively small amount of cyclic nucleotide phosphodiesterase (PDE) activity, the requirement for MIX to visualize intact cell responsiveness to epinephrine could be explained only partially by its PDE inhibitory properties.

Mechanical circulatory assistance with intra-aortic balloon counterpulsation for major abdominal surgery.

Intra-aortic balloon counterpulsation (IABC) provides effective mechanical circulatory assistance (MCA) in many patients with cardiac disease characterized by low cardiac output and/or myocardial ischemia. The intra-aortic balloon pump (IABP) has been used almost exclusively in the care of patients with cardiac disease as their primary medical disorder. This report presents use of the IABP in three cases where cardiac disease was present, but abdominal pathology necessitating urgent surgical intervention was the primary medical concern. Experience with these three cases suggest that operative and early postoperative use of IABC in patients with documented heart disease undergoing major non-cardiac surgical procedures may reduce the high incidence of cardiac complications.

The role of adenosine 3':5'-cyclic monophosphate in the division of WI 38 cells. The cellular response to prostaglandin E1 and the effects of an cyclic adenosine 3':5'-cyclic monophosphate analogue and prostaglandin E1 on cell division.

Inhibition of growth and DNA synthesis was observed in WI 38 cells incubated with 8-methylthioadenosine 3':5'-cyclic monophosphate or prostaglandin E(1). The effect of both compounds on cell growth was reversible. On removal of these compounds from culture media the cells initiated DNA synthesis and divided. In addition, prostaglandin E(1) stimulated cyclic AMP formation in these cells to over 40 times the normal basal value. The increase in cyclic AMP concentration in WI 38 cells after addition of prostaglandin E(1) showed a marked variation. Cells that had recently been treated with trypsin and plated at a lower cell density exhibited a smaller response to addition of prostaglandin E(1) than cells that had divided and reached confluence.