Yet Another Doctor Blog On The Internet

Bromocriptine and puerperal seizures.


Peroxisome proliferator activated receptors (PPARs) are a class of nuclear receptors involved in lipid and glucidic metabolism, immune regulation, and cell differentiation. Many of their biological activities have been studied by using selective synthetic activators (mainly fibrates and thiazolidinediones) which have been already employed in therapeutic protocols. Both kinds of drugs, however, showed pharmacotoxicological profiles, which cannot be ascribed by any means to receptor activation. To better understand these non-receptorial or extrareceptorial aspects, the effect of different PPAR-ligands on the metabolic status of human HL-60 cell line has been investigated. At this regard, NMR analysis of cell culture supernatants was accomplished in order to monitor modifications at the level of cell metabolism. Cell growth and chemiluminescence assays were employed to verify cell differentiation. Results showed that all the considered PPAR-ligands, although with different potencies and independently from their PPAR binding specificity, induced a significant derangement of the mitochondrial respiratory chain consisting in a strong inhibition of NADH-cytochrome c reductase activity. This derangement has been shown to be strictly correlated to the adaptive metabolic modifications, as evidenced by the increased formation of lactate and acetate, due to the stimulation of anaerobic glycolysis and fatty acid beta-oxidation. It is worthy noting that the mitochondrial dysfunction appeared also linked to the capacity of any given PPAR-ligand to induce cell differentiation. These data could afford an explanation of biochemical and toxicological aspects related to the therapeutic use of synthetic PPAR-ligands and suggest a revision of PPAR pathophysiologic mechanisms.

In this case of a possible drug-drug interaction between IFN alfa 11 MU TIW and gemfibrozil 600 mg BID in a patient undergoing treatment for IFN-induced hypertriglyceridemia, the Naranjo Adverse Drug Reactions (ADR) Probability Scale score was 7 (ie, ADR possibly related to treatment).

Pravastatin is an HMG-CoA reductase inhibitor which reduces plasma cholesterol levels by inhibiting de novo cholesterol synthesis and increasing the receptor-mediated catabolism of low density lipoprotein (LDL). Several large multicentre placebo-controlled trials have shown that pravastatin reduces total and LDL-cholesterol levels in a dose-proportional manner in patients with familial or nonfamilial hypercholesterolaemia. Reductions in LDL-cholesterol levels reported in the largest study were 18% (10 mg/day), 23% (20 mg/day) and 31% (40 mg/day) after 12 weeks. Once-daily administration appears to be as effective as two daily doses. Pravastatin consistently increases HDL-cholesterol levels and decreases levels of total triglycerides but these changes are not dose dependent. At the study dosages used, the antihypercholesterolaemic effects of pravastatin were superior to those of bezafibrate and clinofibrate, and were similar to those of simvastatin, lovastatin, gemfibrozil and cholestyramine although in some studies a trend towards a superior effect with pravastatin was seen. Pravastatin did not reduce HDL-cholesterol like probucol, or increase triglyceride levels like cholestyramine. Combined treatment with pravastatin and cholestyramine or colestipol enhances the cholesterol-lowering effects of either drug administered alone and offsets the increase in total triglyceride levels seen with cholestyramine or colestipol therapy. Pravastatin is well tolerated during treatment of up to 24 months but longer term tolerability has not yet been established. The effect of provastatin on cardiovascular events related to elevated plasma cholesterol levels is under investation in several large scale regression and primary and secondary prevention trials.(ABSTRACT TRUNCATED AT 250 WORDS)

It was suggested that postprandial lipoproteins (PPLp) may play an important role in atherogenesis. To examine this hypothesis, we studied PPLp metabolism in normolipidemic individuals and hyperlipoproteinemic (HLP) patients on various diets, physical activity programs and hypolipidemic drugs as well as in patients with coronary artery disease (CAD). We used the vitamin A-fat loading test, which labels intestinally derived lipoproteins with retinyl palmitate. Type IV HLP patients demonstrated a severe defect in chylomicron clearance. Type III HLP patients showed severely disordered clearance of chylomicron remnants. Compared to the saturated fatty acid enriched diet, the omega 6 polyunsaturated acid enriched diet reduced chylomicrons and their remnant levels by 56% and 38%, respectively. The diet enriched in omega 3 polyunsaturated acid decreased chylomicrons and their remnant levels by 67% and 53%, respectively. Physical conditioning reduced chylomicron levels by 37%. Gemfibrozil decreased chylomicron levels in type IV HLP patients. Cholestyramine increased chylomicron levels by 88%. Bezafibrate reduced chylomicrons and their remnants levels and increased fasting HDL-C in patients with isolated low HDL-C levels. Continuous prolonged intravenous heparin administration inhibited chylomicron clearance. Normolipidemic patients with CAD had significantly higher plasma levels of chylomicron remnants than matched controls with normal coronary arteries. The studies reported here demonstrate that both chylomicrons and their remnants are present in the plasma of normolipidemic people and more so for hyper- or dyslipidemic patients for a prolonged period of time after fat ingestion. The duration and magnitude of this postprandial lipemia can be regulated or altered by such interventions as diet, physical activity, and drugs. Our case control studies strongly support the hypothesis that PPLp may play a crucial part in atherogenesis, and therefore justify measuring their levels in high risk patients. We believe that in selected patient groups the use of one or more of the interventions mentioned here is warranted.