Effects of dobutamine and enoximone on transmitral and pulmonary venous flow characteristics in patients with left ventricular dysfunction after coronary artery bypass grafting.

OBJECTIVES: To assess the effects of dobutamine and enoximone on transmitral (TMF) and pulmonary venous flow (PVF) characteristics. DESIGN: Prospective and randomized. SETTING: A university hospital intensive care unit. PARTICIPANTS: Thirty patients with moderate left ventricular dysfunction after coronary artery bypass grafting (CABG). INTERVENTIONS: Patients received either dobutamine, 10 micrograms/kg/min, or enoximone, 20 micrograms/kg/min, for the treatment of a low cardiac index (CI) (< 2.2 L/min/m2). MEASUREMENTS AND MAIN RESULTS: Both drugs significantly (p < 0.05) increased CI from 1.91 +/- 0.17 (dobutamine) and 1.97 +/- 0.17 (enoximone) at baseline to 2.86 +/- 0.70 and 2.84 +/- 0.39 L/min/m2, respectively. Compared with the enoximone (enox)-treated group, the administration of dobutamine (dob) resulted in significantly (p < 0.05) greater increases in mean arterial pressure (dob: 18 +/- 9% v enox: -2 +/- 7%), heart rate (dob: 24 +/- 13% v enox: 3 +/- 5%) and pulmonary artery pressure (dob: 5 +/- 10% v enox: -4 +/- 9%). In contrast, the increase in stroke volume index was significantly less in the dobutamine-treated group (dob: 22 +/- 27% v enox: 41 +/- 21%). The TMF indices, peak E, and peak A wave increased significantly (p < 0.05) after both dobutamine (baseline: 37.3 +/- 6.7 and 41.1 +/- 9.3; max dose: 42.4 +/- 4.3 and 49.0 +/- 10.2 cm/s) and enoximone (baseline: 36.2 +/- 7.5 and 44.2 +/- 10.9; max dose: 40.5 +/- 5.0 and 49.4 +/- 12.1 cm/s) without significantly altering the E/A ratio. Only dobutamine significantly (p < 0.05) decreased isovolumic relaxation time from 109 +/- 24 to 94 +/- 21 ms. There was no significant change in isovolumic relaxation time between the dobutamine (-12% +/- 17%)- and the enoximone (-4% +/- 21%)- treated group. PVF recordings demonstrated a significant increase in time velocity integrals of the S wave with both dobutamine (12.2 +/- 3.1 v 13.7 +/- 3.2 cm) and enoximone (11.0 +/- 3.0 v 12.2 +/- 3.2 cm). No changes in the systolic fraction of the PVF were noted. CONCLUSIONS: There were no major differences in parameters reflecting diastolic function between the dobutamine- and the enoximone-treated groups.

Experimental glomerulonephritis in the rat induced by antibodies directed against tubular antigens. IV. Investigations into the pathogenesis of the model.

Heterologous immune complex glomerulonephritis can be induced in various strains of rats by one injection of heterologous antibody directed against antigens present in the brush border of the proximal. Although it is generally believed that an immune complex glomerulonephritis is caused by the deposition of soluble immune complexes from the circulation in the glomerular basement membrane, there are reasons for doubting whether this mechanism is also operating in the type of experimental glomerulonephritis presented here. In a study using injections of extra antibody and extra antigen to influence the formation and deposition of immune complexes, it is demonstrated that this type of glomerulonephritis is induced in a state of antibody excess. The theory that only immune complexes formed in antigen excess can deposit in the glomerular basement membrane, warrants the assumption that in our model a different pathogenetic mechanism is operating. The hypothesis is put forward that in the heterologous immune complex glomerulonephritis free antibody crosses the glomerular basement membrane to combine with the antigen. This antigen either crosses the glomerular basement membrane separately or is already present as an integral part of this structure.