Search results for "fibra"
showing 10 items of 172 documents
Long cavity ring fiber mode-locked laser with decreased net value of nonlinear polarization rotation
2019
We investigate a new configuration of a mode-locked fiber laser by using a nonlinear polarization rotation-based design to generate soliton pulses with low repetition rate. Unlike with previously reported configurations, we introduce a Faraday mirror after the first half of the cavity length to counteract the nonlinear polarization rotation effects. The total cavity length is 437 m including a 400-m long twisted SMF-28 fiber. The fiber was twisted to cancel the linear birefringence and to ensure that the polarization ellipticity is not altered as the pulse travels along the fiber. The strict control of polarization yields a stable relation between the polarization state of the pulses propag…
Differences in cell proliferation in rodent and human hepatic derived cell lines exposed to ciprofibrate.
2005
International audience; Humans appear to be refractory to some effects of peroxisome proliferators including alterations in cell proliferation, whereas rodents are susceptible. In this study, differences between the human and rat response to peroxisome proliferators were evaluated using rat and human tumour liver cell lines. Rat 7777 cells were more responsive than human HepG2 cells to ciprofibrate as they exhibited a higher decrease in cell number than HepG2, and underwent apoptosis. Results from these studies reveal a surprising response in tumour cell lines as the typical in vivo response of increased cell proliferation and reduced apoptosis was not observed in rat tumour cell lines at c…
NPC1L1 and ABCG5/8 induction explain synergistic fecal cholesterol excretion in ob/ob mice co-treated with PPAR-α and LXR agonists
2020
Reverse cholesterol transport (RCT) and transintestinal cholesterol efflux (TICE) are two important pathways for body cholesterol elimination. We studied these pathways in an animal model of diabetes and obesity (ob/ob) where HDL function is compromised as a result of hyperglycemia, low-grade inflammation and oxidative stress. Co-treatment of ob/ob mice with PPAR-α (fenofibrate) and LXR (T0901317) agonists increased fecal cholesterol by 12-fold; PPAR-α and LXR agonists individually showed 2.6- and 4.0-fold fecal cholesterol excretion, respectively. We investigated the mechanism of synergistic efficacy of PPAR-α and LXR agonists in fecal cholesterol excretion. LXR agonist and the combination…
Elongation and desaturation of arachidonic and eicosapentaenoic acids in rat liver. Effect of clofibrate feeding
1991
The fatty acid elongation-desaturation ability of 5,8,11,14-eicosatetraenoic (20:4(n-6)) and 5,8,11,14,17-eicosapentaenoic (20:5(n-3)) acids was determined in both liver microsomal and light mitochondrial (rich in peroxisomes) fractions of untreated and clofibrate treated rats. The elongation and the subsequent desaturation steps were performed in the corresponding favorable media. 20:5(n-3) elongation was about 2-times more extensive than that of 20:4(n-6). Clofibrate feeding for 10 days resulted in a marked decrease in the elongation rate with the two substrates, while the delta 4 desaturation rate was increased. There were small differences in the elongation rate between the microsomal a…
Induction of the peroxisome proliferator activated receptor by fenofibrate in rat liver
1992
AbstractThe process of peroxisome proliferation in rodent liver by hypolipidemic compounds and related substances has recently been shown to be receptor-madiated. In the present study, we have examined the effect of oral administration of the strong peroxisome proliferator fenofibrate on the hepatic expression level of the peroxisome proliferator activated receptor (PPAR) in rats. Immunoblots of rat liver cytosols and nuclear extracs using antibodies raised against recombinant PPAR/β-galactosidase fusion proteins revealed a pronounced increase in the amount of PPAR protein in response to fenofibrate treatment. This induction could also be confirmed at the level or RNA by Northern blotting. …
Induction of cytochrome P450 isoenzymes in cultured precision-cut rat and human liver slices
1996
1. The effect of some xenobiotics on levels of selected cytochrome P450 (CYP) isoenzymes determined by Western immunoblotting and associated enzyme activities has been studied in 72-h cultured rat and human precision-cut liver slices. 2. In cultured rat liver slices, 0.5 mM sodium phenobarbitone (PB), 25 microM beta-naphthoflavone (BNF), and 20 micrograms/ml Aroclor 1254 (ARO) induced mixed-function oxidase enzyme activities. Western immunoblotting of liver slice microsomes was performed with antibodies to rat CYP1A2, 2B1/2 and 3A. Compared with 72-h control (dimethyl sulphoxide only treated) rat liver slice microsomes, PB induced CYP2B1/2 and 3A, BNF induced CYP1A2, and ARO induced CYP1A2,…
Fasted-state simulated intestinal fluid "FaSSIF-C", a cholesterol containing intestinal model medium for in vitro drug delivery development.
2015
A set of biorelevant media "fasted-state simulated intestinal fluid with cholesterol (FaSSIF-C)" for the in vitro study of intestinal drug dissolution in the duodenum was developed. These contain cholesterol at the same levels as in human bile: the cholesterol content of FaSSIF-7C is equivalent to healthy female, FaSSIF-10C to healthy male persons, and FaSSIF-13C to several disease cases that lead to gallstones. The fluids were studied in three aspects: biocompatibility, intestinal nanostructure, and solubilizing power of hydrophobic drugs of the BCS class II. The biocompatibility study showed no toxic effects in a Caco-2 cell system. The drug-solubilizing capacity toward Fenofibrate, Danaz…
Time-dependence and differential induction of rat and guinea pig peroxisomal beta-oxidation, palmitoyl-CoA hydrolase, cytosolic and microsomal epoxid…
1988
Fischer-344 rats and Hartley guinea pigs received a diet containing 0.01% (w/w), 0.05% (w/w), or 0.25% (w/w) of the hypolipidemic drug fenofibrate. Rats were treated for 4, 7, 14, or 21 days, and a clear dose-dependent and weak time-dependent increase in liver/body weight ratio was observed. The specific activity of peroxisomal beta-oxidation increased linearly with time at all concentrations used. A dose-dependent increase in cEH was observed, but the activity remained constant after treatment for 7 days. Enhancement of palmitoyl-CoA hydrolase was dose-dependent, but was similar at all 4 time points investigated. In contrast to the other enzyme activities, mEH was not or only minimally (le…
Effects of peroxisome proliferator-activated receptor alpha activation on pathways contributing to cholesterol homeostasis in rat hepatocytes
2004
International audience; Peroxisome proliferator-activated receptor alpha (PPARa) activation by fibrates controls expression of several genes involved in hepatic cholesterol metabolism. Other genes could be indirectly controlled in response to changes in cellular cholesterol availability. To further understand how fibrates may affect cholesterol synthesis, we investigated in parallel the changes in the metabolic pathways contributing to cholesterol homeostasis in liver. Ciprofibrate increased HMG-CoA reductase and FPP synthase mRNA levels in rat hepatocytes, together with cholesterogenesis from [14C] acetate and [3H] mevalonate. The up-regulation observed in fenofibrate- and WY-14,643-treate…
IVIVC in oral absorption for fenofibrate immediate release tablets using a dissolution/permeation system.
2009
ABSTRACT: The usefulness of a dissolution/permeation (D/P) system to predict the in vivo performance of solid dosage forms containing the poorly soluble drug, fenofibrate, was studied. Biorelevant dissolution media simulating the fasted and fed state conditions of the human gastrointestinal tract were used in order to simulate the effect of food on the absorption of fenofibrate. Moreover, the results obtained from the D/P system were correlated with pharmacokinetic parameters obtained following in vivo studies in rats. The in vitro parameter (amount permeated in the D/P system) reflected well the in vivo performance in rats in terms of AUC and C max of fenofibric acid. This study thus demon…