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N Diaconescu

Publications and source records attributed to N Diaconescu.

At least 19 recordsLinked to original sources
PubMed1996

Cholesterol-lowering effect of soyabean lecithin in normolipidaemic rats by stimulation of biliary lipid secretion.

The purpose of the present study was to assess the role of the liver in the plasma-cholesterol-lowering effect of soyabean lecithin. Normolipidaemic rats were fed on lecithin-enriched or control diets with the same amount of protein. The lecithin diets contained 200 g/kg high-fat commercial semi-purified soyabean lecithin (230 g/kg total lipids as soyabean phosphatidylcholine) or 200 g/kg high-fat purified soyabean lecithin (930 g/kg total lipids as soyabean phosphatidylcholine). The control diets were a lowfat diet (40 g fat/kg) and a high-fat triacylglycerol-rich diet (200 g fat/kg). The high-fat diets were isoenergetic. The cholesterol-lowering effect of the lecithin-enriched diets was associated with significantly lower levels of plasma total- and HDL-cholesterol and significantly higher levels of bile phosphatidylcholine (PC), bile salts and cholesterol. These findings suggest that the liver plays a major role in the reduction of plasma cholesterol, the increased biliary lipid being provided by both HDL and the hepatic microsomal pools of PC and cholesterol.

Animals↗
PubMed1996

Differences in hypolipidaemic effects of two statins on Hep G2 cells or human hepatocytes in primary culture.

1. The objective of this study was to compare in cultured human hepatocytes or Hep G2 cells, changes in the fate of unesterified low density lipoprotein (LDL)-cholesterol induced by crilvastatin, a new cholesterol lowering drug and a reference statin, simvastatin. 2. The experiments were carried out for 20 h, each well contained 4.2 x 10(5)/cm2 Hep G2 cells or 0.5 x 10(5)/Cm2 human hepatocytes, 130 microM ursodeoxycholate, 0.68 microCi or 1.59 microCi unesterified human [14C]-LDL-cholesterol, crilvastatin or simvastatin at 0 or 50 microM (both cell types) or 300 microM (Hep-G2 cells). Incubation with the two drugs resulted in increased amounts of unesterified [14C]-LDL-cholesterol taken by the two cell types, compared to control. 3. Crilvastatin 50 microM led to significantly higher quantities of [14C]-glyco-tauro-conjugated bile salts, compared to simvastatin. Statins reduced the apo B100 level secreted by the two cell types (simvastatin) or human hepatocytes (crilvastatin). Crilvastatin enhanced both the level of apo A1 secreted by the Hep G2 cells and the level of APF, a high density lipoprotein (HDL) and biliary apoprotein. 4. Crilvastatin not only acts by stimulating LDL-cholesterol uptake by hepatocytes, but also by enhancing the catabolism of LDL-cholesterol in bile salts and probably by stimulating HDL and/or bile component secretion. Such a mechanism was not previously described for HMG CoA reductase inhibitors. Our results on APF show that this apoprotein could be considered also as an indicator of changes in bile and/or HDL compartments. 5. The human hepatocyte model appeared to be a suitable and relevant model in the pharmacological-metabolic experiments carried out in this study. It led to more consistent data than those obtained with Hep G2 cells.

Adult↗
PubMed1995

Effect of crilvastatin, a new cholesterol lowering agent, on unesterified LDL-cholesterol metabolism into bile salts by rat isolated hepatocytes.

1. The aim of these experiments was to determine the effect of crilvastatin, a new cholesterol lowering agent, on the metabolism of unesterified low density lipoprotein (LDL)-cholesterol by rat freshly isolated hepatocytes. This preclinical model was developed as an alternative to in vivo experiments, to mimic the metabolic effects of a molecule on its target cells and to define optimal conditions for future experimentation on human hepatocytes. 2. Cells were obtained from normolipidaemic or hypercholesterolaemic rats, hypercholesterolaemia was nutritionally induced. Incubations were performed in a medium containing 600 microM taurocholate and 50 microM or 300 microM crilvastatin. 3. This molecule was shown in vitro to be carried by physiological transporters, i.e., albumin-bile salt micellar associations and LDL. Crilvastatin induced a significance increase in the synthesis and secretion by hepatocytes of bile salts resulting from the metabolism of unesterified LDL-cholesterol in both normolipidaemic and hypercholesterolaemic rats. Stimulation involved non-conjugated as well as tauro- and glyco-conjugated bile salts. These findings corroborate preliminary studies showing in vivo that crilvastatin enhances the secretion of bile acids by stimulating the uptake and incorporation of LDL-cholesterol by the liver.

Animals↗
PubMed1975

Contribution to the clinical anatomy of the vertebral column. Considerations on the stability and the instability at the height of the "vertebral units".

Based on the findings with human cadaver material and the literature data, the concept of "vertebral unit" is discussed as a basic morphofunctional and pathogenic unit of the vertebral column. The vertebral structures collaborating to the stabilization of the vertebral units are described and a review is made of the possibilities of installation of a vertebral instability. An attempt is made to define the vertebral stability and instability.

Biomechanical Phenomena↗
PubMedDate not supplied

Some peculiarities of osteomedullary interrelations at the level of the lateral wall of the maxillary sinus.

Several structural aspects in the lateral wall of the maxillary sinus are shown, revealing the existence of some peculiarities of the osteomedullary relationships at this level, as for instance: a) a great density of vascular canals, b) a marked collagen density and a high degree of polymerization of the ground substance pleading for a great stability of the osseous structure, and c) a relative cellular scarcity inside the marrow-like spaces as an expression of a reduced reactive ability of bone marrow. It is considered that these peculiarities are not merely determined by specific functional needs of the bone as a tissue, but mainly by subordination of the latter to the requirements of the higher-ordered structural and functional levels served by a certain osseous zone.

Animals↗
PubMedDate not supplied

Biomechanical interpretations of some bony structures in the skull.

For the causal understanding of some evolutive morphological particularities at the level of the lateral wall of orbits (in mammals and in man), the authors have resorted to biomechanical interpretations of bony structures at the cranium level. To this effect some stress factors as well as the modeling effect on the local bone morphogenesis have been analysed.

Animals↗