PubMed Health⌕ Search

Biomedical subjects

C Wolfrum

Publications and source records attributed to C Wolfrum.

17 recordsLinked to original sources
PubMed2005

Oligonucleotides as coding molecules in an anti-counterfeiting system.

Due to the growing numbers of counterfeited products on the world market, there is a huge demand for new and forgery-proof marking systems. We developed a unique system using "molecular beacons" with well adapted thermodynamic parameters. This marking system consists of the three components: DNA tag (a label or directly printing), detection pen (contains the "molecular beacon " solution), and DNA-scanner (reads the specific signal triggered by the detection pen even at daylight). The vast coding capacity of DNA combined with the highly specific signal offers a degree of security that is unmatched by conventional identification technologies.

Biosensing Techniques↗
PubMed2001

Fatty acids and hypolipidemic drugs regulate peroxisome proliferator-activated receptors alpha - and gamma-mediated gene expression via liver fatty acid binding protein: a signaling path to the nucleus.

Peroxisome proliferator-activated receptor alpha (PPARalpha) is a key regulator of lipid homeostasis in hepatocytes and target for fatty acids and hypolipidemic drugs. How these signaling molecules reach the nuclear receptor is not known; however, similarities in ligand specificity suggest the liver fatty acid binding protein (L-FABP) as a possible candidate. In localization studies using laser-scanning microscopy, we show that L-FABP and PPARalpha colocalize in the nucleus of mouse primary hepatocytes. Furthermore, we demonstrate by pull-down assay and immunocoprecipitation that L-FABP interacts directly with PPARalpha. In a cell biological approach with the aid of a mammalian two-hybrid system, we provide evidence that L-FABP interacts with PPARalpha and PPARgamma but not with PPARbeta and retinoid X receptor-alpha by protein-protein contacts. In addition, we demonstrate that the observed interaction of both proteins is independent of ligand binding. Final and quantitative proof for L-FABP mediation was obtained in transactivation assays upon incubation of transiently and stably transfected HepG2 cells with saturated, monounsaturated, and polyunsaturated fatty acids as well as with hypolipidemic drugs. With all ligands applied, we observed strict correlation of PPARalpha and PPARgamma transactivation with intracellular concentrations of L-FABP. This correlation constitutes a nucleus-directed signaling by fatty acids and hypolipidemic drugs where L-FABP acts as a cytosolic gateway for these PPARalpha and PPARgamma agonists. Thus, L-FABP and the respective PPARs could serve as targets for nutrients and drugs to affect expression of PPAR-sensitive genes.

Animals↗
PubMed2000

Binding of fatty acids and peroxisome proliferators to orthologous fatty acid binding proteins from human, murine, and bovine liver.

Liver-type fatty acid binding protein (L-FABP) has been proposed to be involved in the transport of fatty acids and peroxisome proliferators from the cytosol into the nucleus for interaction with the peroxisome proliferator-activated receptors (PPARs). On the basis of this premise, we investigated by isothermal titration calorimetry the binding of myristic, stearic, oleic, and docosahexaenoic acids to three orthologous L-FABPs and compared these results to those obtained for several xenobiotics [Wy14,643, bezafibrate, 5,8,11,14-eicosatetraynoic acid (ETYA), and BRL48,482] known for their peroxisome proliferating activity in rodents. Recombinant human, murine, and bovine L-FABPs were analyzed and the thermodynamic data were obtained. Our studies showed that fatty acids bound with a stoichiometry of 2:1, fatty acid to protein, with dissociation constants for the first binding site in the nanomolar range. With dissociation constants above 1 microM the drug peroxisome proliferators showed weaker binding, with the exception of arachidonate analogue ETYA, which bound with a similar affinity as the natural fatty acid. Some of the thermodynamic data obtained for fatty acid binding could be explained by differences in protein structure. Moreover, our results revealed that binding affinities were not determined by ligand solubility in the aqueous phase.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed2000

Effect of sex and bezafibrate on incorporation of blood borne palmitate into lipids of rat liver nuclei.

The aim of the present study was to investigate whether lipid metabolism in the nuclei is affected by changes in the metabolism of free fatty acids in the liver. The experiments were carried out on 3 groups of rats: 1 - control-male, 2 - female, and 3 - male, treated with bezafibrate (a peroxisome proliferator). The rats received 14C-palmitic acid intravenously. Thirty min later liver samples and blood from the abdominal aorta were taken. The liver nuclei were isolated in sucrose gradient. Lipids were extracted from the nuclei and the liver homogenate and subsequently separated into the following fractions: phospholipids, mono, di- and triacylglycerols, free fatty acids, cholesterol and cholesterol esters. The radioactivity of each fraction was counted. Furthermore, the content of free fatty acids and the fatty acid binding proteins was measured. It was found that radioactivity was present in each lipid fraction obtained from the liver homogenate and from the nuclei. In the female group, the total radioactivity of lipids in the liver homogenate was lower, whereas in the nuclei it was higher in comparison to the male group. The reduction in the radioactivity in the liver was mostly accounted for by decreased radioactivity in the fraction oftriacylglycerols and phospholipids. In the nuclei, the radioactivity of the fraction of phospholipids, free fatty acids and diacylglycerols was elevated. Bezafibrate did not affect the total radioactivity of lipids in the liver and reduced it in the nuclei. In the liver, the drug increased radioactivity mostly in the fraction of phospholipids and reduced it mainly in the fraction of triacylglycerols. In the nuclei, the radioactivity of each lipid fraction examined was reduced. The content of the fraction of free fatty acids in the liver and in the nuclei in the female and in the bezafibrate-treated groups did not differ from the respective value in the control group. The content of fatty acid binding proteins in the nuclei of the female and bezafibrate-treated groups increased in parallel to the elevation in their content in the cytosol. It is concluded that the female sex hormones and bezafibrate influence the transport of selected lipids into the nuclei. The effects seem to be a consequence of the action of these factors directly on the nucleus.

Active Transport, Cell Nucleus↗
PubMed1999

Variation of liver-type fatty acid binding protein content in the human hepatoma cell line HepG2 by peroxisome proliferators and antisense RNA affects the rate of fatty acid uptake.

The liver-type fatty acid binding protein (L-FABP), a member of a family of mostly cytosolic 14-15 kDa proteins known to bind fatty acids in vitro and in vivo, is discussed to play a role in fatty acid uptake. Cells of the hepatoma HepG2 cell line endogenously express this protein to approximately 0.2% of cytosolic proteins and served as a model to study the effect of L-FABP on fatty acid uptake, by manipulating L-FABP expression in two approaches. First, L-FABP content was more than doubled upon treating the cells with the potent peroxisome proliferators bezafibrate and Wy14,643 and incubation of these cells with [1-14C]oleic acid led to an increase in fatty acid uptake rate from 0.55 to 0.74 and 0.98 nmol/min per mg protein, respectively. In the second approach L-FABP expression was reduced by stable transfection with antisense L-FABP mRNA yielding seven clones with L-FABP contents ranging from 0.03% to 0.14% of cytosolic proteins. This reduction to one sixth of normal L-FABP content reduced the rate of [1-14C]oleic acid uptake from 0.55 to 0. 19 nmol/min per mg protein, i.e., by 66%. The analysis of peroxisome proliferator-treated cells and L-FABP mRNA antisense clones revealed a direct correlation between L-FABP content and fatty acid uptake.

Bezafibrate↗
PubMed1999

Phytanic acid activates the peroxisome proliferator-activated receptor alpha (PPARalpha) in sterol carrier protein 2-/ sterol carrier protein x-deficient mice.

We showed recently that a targeted null mutation in the murine sterol carrier protein 2-/sterol carrier protein x-gene (Scp2) leads to defective peroxisomal catabolism of 3,7,11, 15-tetramethylhexadecanoic acid (phytanic acid), peroxisome proliferation, hypolipidemia, and enhanced hepatic expression of several genes that have been demonstrated to be transcriptionally regulated by the peroxisome proliferator-activated receptor alpha (PPARalpha). As a broad range of fatty acids activates PPARalpha in vitro, we examined whether the latter effects could be because of phytanic acid-induced activation of this transcription factor. Dietary phytol supplementation was used to modulate the concentration of phytanic acid in C57Bl/6 and Scp2 (-/-) mice. We found that the serum concentrations of phytanic acid correlated well with the expression of genes encoding peroxisomal beta-oxidation enzymes and liver fatty acid-binding protein, which have all been demonstrated to contain functionally active peroxisome proliferator response elements in their promoter regions. In accordance with these findings, a stimulating effect on acyl-CoA oxidase gene expression was also observed after incubation of the rat hepatoma cell line MH1C1 with phytanic acid. Moreover, reporter gene studies revealed that phytanic acid induces the expression of a peroxisome proliferator response element-driven chloramphenicol transferase reporter gene comparable with strong peroxisome proliferators. In addition, the ability of phytanic acid to act as an inductor of PPARalpha-dependent gene expression corresponded with high affinity binding of this dietary branched chain fatty acid to recombinant PPARalpha. We conclude that phytanic acid can be considered as a bona fide physiological ligand of murine PPARalpha.

Acyl-CoA Oxidase↗
PubMed1999

Phytanic acid is ligand and transcriptional activator of murine liver fatty acid binding protein.

Branched-chain phytanic acid is metabolized in liver peroxisomes. Sterol carrier protein 2/sterol carrier protein x (SCP2/SCPx) knockout mice, which develop a phenotype with a deficiency in phytanic acid degradation, accumulate dramatically high concentrations of this fatty acid in serum (Seedorf at al. 1998. Genes Dev. 12: 1189-1201) and liver. Concomitantly, a 6.9-fold induction of liver fatty acid binding protein (L-FABP) expression is observed in comparison to wild-type animals fed standard chow, possibly mediated by the peroxisome proliferator-activated receptor alpha (PPARalpha). Cytosolic transport of phytanic acid to either peroxisomal membranes or to the nucleus for activation of PPARalpha may be mediated by L-FABP, which gives rise to the question whether phytanic acid is a transactivator of this protein. Here we show first that phytanic acid binds to recombinant L-FABP with high affinity. Then the increase of the in vivo phytanic acid concentration by phytol feeding to mice results in a 4-fold induction of L-FABP expression in liver, which is in the order of that attained with bezafibrate, a known peroxisome proliferator. Finally to test in vitro whether this induction is conferred by phytanic acid, we cotransfected HepG2 cells with an expression plasmid for murine PPARalpha and a CAT-reporter gene with 176 bp of the murine L-FABP promoter, containing the peroxisome proliferator responsive element (PPRE). After incubation with phytanic acid, we observed a 3.2-fold induction of CAT expression. These findings, both in vivo and in vitro, demonstrate that phytanic acid is a transcriptional activator of L-FABP expression and that this effect is mediated via PPARalpha.

Animals↗
PubMed1992

Controlled comparison of RO 11-1163 (moclobemide) and placebo in the treatment of depression.

Moclobemide was compared to placebo in two parallel groups of depressed patients, in a multicenter randomized, double-blind study of six weeks treatment duration. Forty seven patients participated in the study: 23 received moclobemide (flexible dose 300-600 mg/day) and 24 placebo. They were evaluated weekly for efficacy and tolerability. Moclobemide was more efficacious than placebo as judged by analysis on the total score on the Hamilton depression scale (p < 0.05) and by the overall assessment of efficacy (p < 0.01). Moclobemide was also more effective than placebo in the subgroup with neurotic depression (p < 0.05). In addition, the number of patients prematurely terminating treatment for inefficacy, was higher in the placebo than in the moclobemide group (12 versus 2, p < 0.01). The number and the severity of side-effects tended to be slightly greater in the moclobemide than in the placebo group, but this did not reach a level of significance. Cardiovascular tolerability was good in both treatment groups. No hypertensive crisis was reported. Hematology, clinical chemistry and urine analysis were not affected by the treatment in any clinically significant fashion.

Adult↗
PubMed1990

Moclobemide versus placebo in the treatment of depression: a multicentre study in Belgium.

Moclobemide was compared with placebo for antidepressant activity, tolerance and safety in 2 parallel groups of 23 and 24 depressed patients. At the end of treatment (4 weeks or longer), 9 patients on moclobemide (41%) showed an improvement greater than or equal to 50% on the Hamilton Rating Scale for Depression, compared with only 4 (17%) of those on placebo. The overall assessment of efficacy was significantly better for moclobemide (good or very good results in 50% of patients) than for placebo (80% poor results). Moclobemide was well or very well tolerated by 85% of patients and placebo by 100%. Moclobemide was thus shown to be clearly more effective than placebo and only slightly less well tolerated.

Antidepressive Agents↗
PubMed1990

Moclobemide versus clomipramine in the treatment of depression: a double-blind multicentre study in Belgium.

Moclobemide and clomipramine were compared for efficacy, tolerance and safety in 63 mixed endogenous and nonendogenous depressed patients. Treatment was given for at least 4 weeks in a double-blind, randomized, parallel-group design. The mean Hamilton Rating Scale for Depression score decreased gradually during treatment with no differences between groups. Two patients on clomipramine and none on moclobemide were withdrawn for lack of efficacy, and poor tolerance caused 3 patients on moclobemide and 7 on clomipramine to stop treatment prematurely. Patients with endogenous depression responded better to clomipramine, whereas nonendogenous disorders did better on moclobemide. Adverse events were more frequent in the clomipramine group and more of these were severe or very severe than for moclobemide. Thus, although no significant difference in efficacy was seen, moclobemide appeared to be tolerated better than clomipramine. The numbers were small, however, and many patients received concomitant medication, and the results are therefore difficult to interpret.

Antidepressive Agents↗
PubMed1990

Moclobemide versus amitriptyline in the treatment of depression: two small double-blind multicentre studies in Belgium.

Moclobemide was compared with amitriptyline for antidepressant efficacy, safety and tolerance. Two studies were conducted, both over at least 4 weeks; in the first, 8 patients were given moclobemide in doses ranging from 300 to 328 mg, and 9 patients amitriptyline in doses of 75 to 96 mg; in the second, the numbers were 13 on moclobemide and 14 on amitriptyline, and the mean doses were 294-408 mg and 95-129 mg respectively. Both studies showed the 2 treatments to be equally effective, and there were no significant differences at any point. Moclobemide appeared slightly more effective and slightly better tolerated than amitriptyline, but the numbers were too small for any valid conclusion.

Adult↗
PubMed1985

Comparing the effects of pimozide and placebo in a single case experiment.

A single case experiment as suggested by Edgington (1980) was carried out to answer the difficult question whether the continuation of treatment with neuroleptics was appropriate for a patient who still suffered from paranoia after inpatient treatment and continuous two-year administration of neuroleptics thereafter. A 24-weeks' experiment was arranged with the patient which was carried out under double-blind conditions. The experiment was planned in a way that it could be analysed with the help of a randomisation test. Physician's and patient's global ratings concerning the patient's condition and drug side effects were assessed weekly. In addition, psychopathological symptoms were measured by the Simpson-scale. Every week, the patient described her emotional state with the help of the Adjective Check List by Janke. Following the results of the experiment, medication was discontinued. This resulted in a distinct reduction of her complaints during a follow-up period of now 2 years. Although conducting single case experiments seems to be desirable for adequate problems, there are only few possibilities for practical application because of difficulties with planning and execution.

Female↗
PubMed1984

Single case experiments in psychopharmacological trials.

Single case experiments have been used to make pharmacotherapeutic decision making more objective. 4 single case experiments are presented. In the case of 3 patients the question was whether flunitrazepam (Rohypnol) should be administered. In the 4th patient the issue was whether self-administration of Limbitrol (amitriptyline + chlordiazepoxide) should be terminated. Planning and analysis of these experiments was carried out by the randomization test.

Adult↗
PubMed1979

[Configural frequency analysis. X. Therapy outcome assessment using prediction configural frequency analysis].

Starting from falsely equal and falsely unequal rates of successive psychotherapies, the prediction configural frequency analysis is introduced for evaluating psychotherapeutic effects by stratifying patients. As stratificator variables, intelligence quotients and sex of patients are used paradigmatically to predict strata-specific therapeutic effects and to compare different therapies conclusively even if patients cannot be assigned randomly to therapies. Prediction types of success are defined by those stratification patterns which favour therapeutic success.

Behavior Therapy↗