Biomedical subjects

W Leonhardt

Publications and source records attributed to W Leonhardt.

93 records · Page 6Linked to original sources

PubMedDate not supplied

Elimination of lipofundin S during the intravenous fat tolerance test in patients with low, medium, and high fasting triglyceride concentrations.

The intravenous fat tolerance test with Lipofundin S (0.5 ml of 20% emulsion/kg body weight) was performed in 22 male nondiabetic patients. According to their fasting triglycerides (TG), the patients were arranged into three groups: low (less than 2.8 mmol/liter), medium (2.8-5.7 mmol/liter), and high (greater than 5.7 mmol/liter) concentrations. Fractional elimination rates of injected Lipofundin S decreased from 11.08 in low TG to 4.57%/min in high TG; they were positively correlated with fasting levels of high-density lipoprotein cholesterol but negatively with those of TG. The same pattern of correlations was observed with fractional catabolic rates of endogenous TG as measured after injection of tritium-labeled glycerol. The intravenous Lipofundin S load effected transient TG and free fatty acid elevations which were delayed in high TG. The elimination mechanisms of injected Lipofundin S and of endogenous TG are compared.

Adult↗

PubMedDate not supplied

Elimination kinetics of Lipofundin MCT: bolus injection and infusion compared.

Fifteen healthy young probands (nine males, six females) underwent an intravenous fat tolerance test (IVFTT) and, on the following day, a fat infusion lasting 6 hr. The emulsion tested was Lipofundin MCT 10%. One half of its triglyceride mass contains medium chain fatty acids. The IVFTT was started by injection of 0.1 g lipid per kg body weight into the fasting proband. Lipid elimination was estimated by measurement of light-scattering intensity of serum samples collected during a 60-min period. Individual fraction elimination rate constants covered a considerable range (K2 = 8.84 +/- 3.45%/min). The infusion test was performed at a rate of 0.1 g lipid per kg body weight and hr and lasted 6 hr. Serum triglyceride concentrations were determined enzymatically. They increased from 0.941 +/- 0.285 mmol/liter at the fasting state to a plateau level of 1.753 +/- 0.306 mmol/liter during infusion, and returned to initial levels 1 to 2 hr after the infusion was terminated. Individual triglyceride increments during infusion were significantly correlated with half-life periods of lipid elimination during IVFTT (r = 0.792, p less than 0.001). This relationship was derived using a model of the stationary state during infusion. We conclude that elimination kinetics of exogenous fat given either as bolus or infusion are ruled by the same fractional elimination rate constant K2. The IVFTT provides an estimate of the stationary triglyceride increment during a lipid infusion lasting several hr.

Adult↗

PubMedDate not supplied

Elimination and metabolism of a fat emulsion containing medium chain triglycerides (lipofundin MCT 10%).

Medium chain triglycerides (MCT) are supposed to be advantageous on account of rapid energy supply in parental nutrition. However, data on the elimination rate of MCT-containing emulsions during an intravenous fat-tolerance test (IVFTT) are scarce. We performed this test (0.1 g lipid/kg body weight) in 18 young healthy volunteers (nine females and nine males) using Lipofundin MCT 10% (50% MCT; egg phospholipids as emulsifier). Our results indicate that both elimination and metabolization of the emulsion are fast: a prompt decrease of light-scattering index and of triglyceride concentrations in serum, an immediate appearance of post-load fatty acids and of beta-hydroxybutyrate were observed. This was in good agreement with the findings obtained during 6-hr infusions in the same probands. Fractional elimination rates k2 obtained from light-scattering indices are 7.29 +/- 2.73%/min in males and 11.59 +/- 3.38%/min in females, indicating a higher removal capacity in women. In the same subjects, the corresponding k2 values for Lipofundin S 10% (containing only long chain triglycerides) were higher, reflecting an elimination rate that is faster due to the use of soya bean phospholipids as emulsifier. In comparison, k2 values based on the course of the triglyceride concentrations are generally lower.

3-Hydroxybutyric Acid↗