The influence of sustained release theophylline therapy on free fatty acids in serum.

The serum concentrations of theophylline, total free fatty acids (FFA) and subgroups were studied in ten healthy volunteers treated with sustained release theophylline twice daily during 9 days. Analyses were performed before and on day 1, 4 and 9 of treatment. Mean theophylline serum levels within the therapeutic range were obtained during the study, ranging from 62 +/- 7 to 82 +/- 10 mumol/l. The mean serum concentrations of total FFA and subgroups increased significantly during treatment, showing the highest levels on day 4. Comparing fasting total FFA concentrations, an increase of 123% and 48% from pretreatment levels were found on day 4 and 9, respectively. The subgroups were influenced to a different degree by theophylline intake. Arachidonic acid (20:4) was not increased, while among the others, saturated FFA increased less than the unsaturated.

Toxicity of plasma from hemodialysis patients treated with heparin or prostacyclin.

Hemodialysis was performed in 6 uremic patients with either a bolus dose of 5 000 IU heparin or prostacyclin at a constant infusion rate of 5 ng/kg/min. Clinical data, plasma triglycerides (TG), free fatty acids (FFA), platelet aggregation, white blood cell count and plasma toxicity were measured prior to and during both procedures. No serious side-effects were recorded. Heparin induced a fall in plasma TG, a rise in FFA and increased plasma toxicity. Prostacyclin infusion had no effect on these parameters. During both tests a marked drop in white blood cell count was found 15 min after the start of hemodialysis. During heparin dialysis no clotting was observed in the extracorporeal circuit. During prostacyclin dialysis clotting was observed at the venous line in three cases.

Hemodialysis and cell toxicity in vitro related to plasma triglycerides, post-heparin lipolytic activity and free fatty acids.

Plasma triglyceride (TG) concentrations, post-heparin lipolytic activities and the free fatty acid (FFA) pattern of uremic and normal plasma were compared and correlated to plasma toxicity as measured by the effect on human mononuclear phagocytes cultured in vitro. Plasma TG concentration and FFA: albumin molar ratios were significantly higher in uremic plasma, and a correlation was found between TG concentrations prior to heparinization and post-heparin FFA concentrations. Uremic plasma toxicity was significantly correlated to increased post-heparin FFA: albumin molar ratio. The post-heparin lipoprotein lipase activity in uremic plasma collected 120 min after heparinization was higher than in normal plasma. Qualitative and quantitative experiments in vitro showed increased plasma toxicity with increasing FFA: albumin molar ratios. The proportion of unsaturated FFA in uremic post-heparin plasma increased compared to saturated FFA during incubation for 96 hours. Altered lipid metabolism after systemic heparinization thus seems to be important for the cell toxicity of uremic plasma in vitro.

The effect of systemic heparinization on plasma lipoproteins and toxicity in patients on hemodialysis and continuous ambulatory peritoneal dialysis.

The lipid patterns of plasma from 6 patients on hemodialysis (HD) and 6 patients on continuous ambulatory peritoneal dialysis (CAPD) were compared and correlated to plasma toxicity as measured by the survival of human macrophages cultured in vitro. The median values for plasma triglycerides (TG), cholesterol, low density lipoprotein (LDL) cholesterol, apolipoprotein B and lipolytic activities (lipoprotein lipase and hepatic lipase) were insignificantly higher in CAPD plasma than in HD plasma. The median high density lipoprotein (HDL) cholesterol/LDL cholesterol ratio was significantly higher in HD plasma than in CAPD plasma. In both groups systemic heparinization was followed by a significant increase in free fatty acids and in plasma toxicity. The difference in plasma toxicity was insignificant. In the whole group of patients (n = 12) toxicity in post-heparin plasma was correlated to pre-heparin very low density lipoprotein (VLDL) TG, but not to LDL TG. Separately post-heparin toxicity in CAPD plasma was correlated to pre-heparin total TG, VLDL TG and post-heparin LDL TG.