Multiple solutions for a class of Dirichlet double eigenvalue quasilinear elliptic systems involving the (p1,…, pn)-Laplacian operator.

Existence results of three weak solutions for a Dirichlet double eigenvalue quasilinear elliptic system involving the (p1,…, pn)-Laplacian operator, under suitable assumptions, are established. Our main tool is based on a recent three-critical-point theorem obtained by Ricceri. We also give some examples to illustrate the obtained results.

Contribution of apolipoprotein(a) size, pentanucleotide TTTTA repeat and C/T(+93) polymorphisms of the apo(a) gene to regulation of lipoprotein(a) plasma levels in a population of young European Caucasians.

Several studies indicate that the inter-individual variation in plasma concentrations of lipoprotein(a) (Lp(a)) is mainly under genetic control. To define the effect of three DNA polymorphisms on apolipoprotein(a) (apo(a)) expression, we have determined plasma Lp(a) concentrations, apo(a) isoform size, KpnI allele size, the TTTTA pentanucleotide repeat number in the 5' control region of the apo(a) gene and the +93 C/T polymorphism in a European Caucasian population. The simultaneous determination of the kringle 4 (K4) number by genotyping and by phenotyping revealed that the size distribution of non-expressed apo(a) alleles was markedly skewed towards alleles with greater than 25 K4 repeats.

Effects of fish oil fatty acids on plasma lipids and lipoproteins and oxidant-antioxidant imbalance in healthy subjects.

The purpose of this study was to investigate the effect of eicosapentaenoic and docosahexaenoic acids on plasma lipids and lipoproteins, lipid peroxidation and antioxidant status in healthy humans. A total of 19 healthy volunteers consumed 6 g/day Maxepa fish oil for 3 weeks (1.8 g n-3 fatty acids/day).

[Focalized matrix proteolysis and inflammation].

The zinc metalloproteinases (MMPs or matrixins) are capable of damaging most of the constituents of the extra-cellular matrix and the basement membrane. The matrix proteolysis is the result of an imbalance both in the turnover of these constituants and in the ratio of the tissue inhibitors of metalloproteinases (TIMPs) versus metalloproteinases. After a brief description of the nature and structure of MMPs and TIMPs, this article reports on recent progress concerning the intra and extra-cellular activation mechanisms of proenzymes (proMMPs) which bring into play a series of proteolytic activations involving different proteinase families.

Evaluation of the genotyping and phenotyping approaches in the investigation of apolipoprotein (a) size polymorphism.

Apoprotein (a) size polymorphism was evaluated at the genotypic and phenotypic level in 110 individuals. Both methods were well correlated with respect to size (r = 0.971), providing that the protein size was expressed as a number of kringle 4 repeats.

Altered antioxidant status and increased lipid peroxidation in children with cystic fibrosis.

Cystic fibrosis often combines an infectious pathology with a syndrome of malabsorption, both potentially capable of favoring the deleterious effects of reactive oxygen species. This study was a simultaneous evaluation of the main antioxidant systems dependent on micronutrients and of lipid peroxidation products in 27 children with cystic fibrosis and 17 healthy children. Plasma of cystic fibrosis patients showed very low concentrations of beta-carotene (0.

Zinc deficiency does not enhance LDL uptake by P 388 D1 macrophages in vitro.

The aim of the study was to investigate the effect of zinc depletion on the susceptibility of Wistar rat low-density lipoproteins (LDL) to peroxidation and their uptake by macrophages, before and after in vitro oxidation. The rats were fed for 7 wk a Zn-adequate diet (100 ppm) ad libitum (AL), a Zn-deficient diet (0.2 ppm) ad libitum (ZD), or a Zn-adequate diet according to the pair-feeding method (PF).

Malondialdehyde kit evaluated for determining plasma and lipoprotein fractions that react with thiobarbituric acid.

The determination of thiobarbituric acid reactants (TBARs) is a widely used method for investigating overall lipid peroxidation. An assay kit that could be used with plasma and lipid fractions would facilitate standardization of the method. The results reported here indicate that the malondialdehyde (MDA) kit manufactured by Sobioda (Grenoble, France) complies with criteria of good analytical practices.

[Contribution of molecular biology to the diagnosis of familial hypercholesterolemias in children].

The detection of children at high risk in families with a genetic form of hypercholesterolemia is important for acceptance of prevention under medical control. However, usual lipidic parameters are difficult to interpret during infancy. So we studied by a molecular biology approach 11 families presenting with syndrome of pure hypercholesterolemia where a defect of the LDL receptor (LDL-R) gene was suspected (Familial Hypercholesterolemia: FH IIa).

Effect of an acute zinc depletion on rat lipoprotein distribution and peroxidation.

The aim of this study was to determine the extent to which zinc depletion leads to lipoprotein modifications by measuring both lipoprotein-fraction distribution and peroxidation in zinc-depleted rats. The animals were divided into three groups and fed for 8 wk a zinc-adequate diet (100 ppm) ad libitum (AL), a zinc-deficient diet (0.2 ppm) ad libitum (ZD), or a zinc-adequate diet according to the pair feeding method (PF).

Rapid polyphosphoinositide decrease is an early event in the steroidogenic response of bovine adrenocortical fasciculata cells to angiotensin II.

Addition of angiotensin II (0.3 microM) to bovine adrenal fasciculata cell suspensions prelabeled with [32P] induced a rapid (15 seconds) and marked decrease of the radioactivity from phosphatidylinositol 4,5-biphosphate (62%) and phosphatidylinositol 4-monophosphate (35%). This effect was concentration-dependent and specifically inhibited in the presence of (Sar1-Ala8)-angiotensin II; it was also completely prevented in the absence of extracellular calcium.

Steroidogenic effect of exogenous phospholipase C on bovine adrenal fasciculata cells.

Phospholipase C (Bacillus cereus) added to the incubation medium stimulated the steroidogenic activity of bovine adrenal zona fasciculata cell suspensions to a level similar to that induced by optimal concentration of ACTH. This effect was not related to an increase of cyclic AMP; it was calcium-dependent and was also induced by an other bacterial phospholipase C (from Clostridium perfringens) whereas phospholipases A2 and D were ineffective. Phospholipid metabolism was examined in these cells after radiolabeling with [14C]-glycerol or [32P]orthophosphate.

Stimulation of phosphatidylinositol turnover by acetylcholine, angiotensin II and ACTH in bovine adrenal fasciculata cells.

The effect of acetylcholine, angiotensin II and adrenocorticotropin (ACTH) on phosphatidylinositol (PI) metabolism was examined using bovine adrenocortical fasciculata cell suspensions. The three agents, which acutely stimulate glucocorticoid production by these cells, were all able to increase [32P]Pi incorporation into cellular PI. However, whereas the relative steroidogenic potency (at maximally active concentrations) was ACTH greater than or equal to angiotensin II greater than acetylcholine, the effect on PI labeling was in the order angiotensin II greater than acetylcholine greater than ACTH.

Cholinergic muscarinic stimulation of steroidogenesis in bovine adrenal cortex fasciculata cell suspensions.

Acetylcholine was found to acutely stimulate cortisol production by bovine fasciculata adrenocortical cell suspensions. This effect was maximal at 10(-4) M acetylcholine concentration, resulted in a 5-fold increase in cortisol production over the control after 1 h incubation, and represented about one fifth of the ACTH maximal stimulation under the same conditions. Acetylcholine-stimulated steroidogenesis was concentration-dependent (10(-8)-10(-5) M), proportional to the cell number (5 X 10(5)-1 X 10(6)) and reached a plateau after 30 min incubation.

Sterospecific tissue uptake and nuclear accumulation of testosterone in the development of the mouse erythropoietic spleen.

A double isotope ratio technique was used to estimate the specific binding of testosterone (T), as opposed to its biologically nonactive stereoisomer, epitestosterone (Epi T). The mouse erythropoietic spleen formed in response to a phenylhydrazine-induced hemolytic anemia was used as the target organ. Spleen minces from preanemic mice, as well as those in the early and late phases of erythropoietic spleen development, were incubated with 10(-9) M of 14C-T and 3H-EpiT, and the selective uptake of T was calculated from the 14C/3H ratio measured in the media before and after incubation, as well as in the subcellular fractions of the minces.

Androgen receptor in human skin fibroblasts. Characterization of a specific 17beta-hydroxy-5alpha-androstan-3-one-protein complex in cell sonicates and nuclei.

Cultured human skin fibroblasts were shown to contain an androgen binding activity (receptor) which was heat-labile and destroyed by trypsin. Specific binding was seen after incubations of these cells with 1,2-3-H-testosterone, 1,2-3-H17beta-hydroxy-5alpha-androstan-3-one (dihydrotestosterone, DHT) and 1,2-3-H-5alpha-androstane-3alpha, 17beta-diol. This receptor had a high affinity (Kd=0,2-1.