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R Wouters

Publications and source records attributed to R Wouters.

12 recordsLinked to original sources
PubMed2001

Combined use of Lactobacillus reuteri and soygerm powder as food supplement.

AIMS: The survival of Lactobacillus reuteri when challenged with glycodeoxycholic acid (GDCA), deoxycholic acid (DCA) and soygerm powder was investigated. Moreover, the impact of Lact. reuteri on the bioavailability of isoflavones present in soygerm powder was examined. METHODS AND RESULTS: The strain experienced a die-off when adding 2 or 3 mmol l-1 bile salts, with more pronounced effects in the case of DCA. By means of a haemolysis test it was shown that toxicity could be due to membrane damage. When 4 g l-1 soygerm powder was added, the Lactobacillus strain survived the bile salt burden better (P < or = 0.05) and the membrane damage in the haemolysis test decreased (P < or = 0.05). The Lact. strain cleaved beta-glycosidic isoflavones during fermentation of milk supplemented with soygerm powder. CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: The interactions between the Lactobacillus strain and soygerm powder suggest that combining both in fermented milk can exhibit advantageous probiotic effects. The relevance of the combination of the strain and the soygerm powder should be studied under more relevant physiological conditions.

Animals↗
PubMed2001

Probiotic removal of herbicides with endocrine disrupting potential from aqueous matrices.

Water dosed with 50 mg/L of 2,4-D and atrazine was treated to remove the herbicides which both are reported to have endocrine disrupting potential. Both chemicals could be removed effectively with activated carbon. Yet, traces of endocrine disrupter remained in the water and are able to enter the food chain. The further biological elimination of these compounds was investigated. Milk alone did not decrease the amount of chemicals present in the aqueous supernatant. Yet, the probiotic products Bifidus yoghurt (GB), Actimel (Danone) and Yakult (Yakult Honsha) appeared to bind a substantial amount of the endocrine disrupting chemicals to the particulate fraction and thus render them potentially less bio-available in the aqueous phase.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2000

Protective effect of the bile salt hydrolase-active Lactobacillus reuteri against bile salt cytotoxicity.

Bacterial bile salt hydrolysis is considered a risk factor for the development of colon cancer because of the risk of forming harmful secondary bile salts after an initial deconjugation step. In this study, the influence of enhanced bacterial bile salt transformation by the bile salt hydrolase-active Lactobacillus reuteri was studied in batch culture using the microbial suspension of the Simulator of the Human Intestinal Microbial Ecosystem; (SHIME), which was supplemented with oxgall at 5 g/l or 30 g/l. Changes in the fermentative capacity of the microbial ecosystem and the (geno)toxic properties of the SHIME supernatants were investigated. Increasing concentrations of oxgall inhibited the fermentation. Transient cell toxicity was observed for samples supplemented with 5 g oxgall/l, while samples with 30 g oxgall/l exhibited toxicity. The results of the haemolysis test suggest that the detrimental effects were probably due to the membrane-damaging effects of bile salts. In all cases, the adverse effects could be counteracted by the addition of 7.5 +/- 0.5 log10 CFU L. reuteri/ml. Plausible mechanisms for the protective properties of L. reuteri could involve a precipitation of the deconjugated bile salts and a physical binding of bile salts by the bacterium, thereby making the harmful bile salts less bioavailable.

Amidohydrolases↗
PubMed2000

Influence of a synbiotic mixture consisting of Lactobacillus acidophilus 74-2 and a fructooligosaccharide preparation on the microbial ecology sustained in a simulation of the human intestinal microbial ecosystem (SHIME reactor).

Lactobacillus acidophilus 74-2, which is used in probiotic products, was administered, with fructo-oligosaccharide in a milk-based product, to the second vessel (duodenum/jejunum) of the SHIME reactor, an in vitro simulation of the human intestinal microbial ecology. The main focus of this study was to monitor the changes of the population density of selected bacterial species in the intestine and the changes of metabolic activities during the supplementation of L. acidophilus and fructooligosaccharide in the SHIME reactor. Interestingly, the addition of L. acidophilus 74-2 with fructooligosaccharide gave rise to an increase of bifidobacteria. Moreover, major positive changes occurred in the production of volatile fatty acids: a strong upward trend was observed especially in the case of butyric acid and propionic acid. Furthermore a noticeable increase of beta-galactosidase activity was monitored, while the activity of beta-glucuronidase, generally considered undesirable, declined.

Animals↗
PubMed1998

Agonistic properties of alniditan, sumatriptan and dihydroergotamine on human 5-HT1B and 5-HT1D receptors expressed in various mammalian cell lines.

1. Alniditan, a novel migraine abortive agent, is a potent 5-HT1B/5-HT1D receptor agonist of nM affinity. We compared the agonistic properties of alniditan, sumatriptan and dihydroergotamine on the cloned human 5-HT1B receptor expressed at 200 fmol mg(-1) protein (Bmax) in non-induced L929sA cells, at 740 fmol mg(-1) protein in HEK 293 and at 2300 fmol mg(-1) protein in mIFNbeta-induced L929sA cells, and on the human cloned 5-HT1D receptor expressed in C6 glioma cells (Bmax 780 fmol mg(-1) protein). 2. Sodium butyrate treatment increased the expression level of human (h)5-HT1B receptors in HEK 293 cells and h5-HT1D receptors in C6 glioma cells approximately 3 fold, the binding affinities of [3H]-5-HT and [3H]-alniditan were unaffected. 3. Agonistic properties were evaluated based on inhibition of cyclic AMP accumulation in the cells after stimulation of adenylyl cyclase by forskolin or isoproterenol. Alniditan, sumatriptan and dihydroergotamine were full agonists at the hS-HT1B receptor (IC50 values were 1.7, 20 and 2 nM, respectively in HEK 293 cells) and hS-HT1D receptors (IC50 values of 1.3, 2.6 and 2.2 nM, respectively). At the h5-HT1B receptor the agonist potency of the compounds slightly increased with higher receptor density. The opposite was seen for antagonists (ocaperidone, risperidone and ritanserin). 4. This comparative study demonstrated that alniditan was 10 times more potent than sumatriptan at the h5-HT1B receptor, and twice as potent at the h5-HT1D receptor. Dihydroergotamine was more potent an agonist at the h5-HT1B receptor when expressed at high and low level in L929sA cells (but not in HEK 293 cells), and was less potent at the hS-HT1D receptor.

Adenylyl Cyclases↗
PubMed1996

Alniditan, a new 5-hydroxytryptamine1D agonist and migraine-abortive agent: ligand-binding properties of human 5-hydroxytryptamine1D alpha, human 5-hydroxytryptamine1D beta, and calf 5-hydroxytryptamine1D receptors investigated with [3H]5-hydroxytryptamine and [3H]alniditan.

Alniditan is a new migraine-abortive agent. It is a benzopyran derivative and therefore structurally unrelated to sumatriptan and other indole-derivatives and to ergoline derivatives. The action of sumatriptan is thought to be mediated by 5-hydroxytryptamine (5-HT)1D-type receptors. We investigated the receptor-binding profile in vitro of alniditan compared with sumatriptan and dihydroergotamine for 28 neurotransmitter receptor subtypes, several receptors for peptides and lipid-derived factors, ion channel-binding sites, and monoamine transporters. Alniditan revealed nanomolar affinity for calf substantia nigra 5-HT1D and for cloned h5-HT1D alpha, h5-HT1D beta and h5-HT1A receptors (Ki = 0.8, 0.4, 1.1, and 3.8 nM, respectively). Alniditan was more potent than sumatriptan at 5-HT1D-type and 5-HT1A receptors. Alniditan showed moderate-to-low or no affinity for other investigated receptors; sumatriptan showed additional binding to 5-HT1F receptors. Dihydroergotamine had a much broader profile with high affinity for several 5-HT, adrenergic and dopaminergic receptors. In signal transduction assays using cells expressing recombinant h5-HT1D alpha, h5-HT1D beta, or h5-HT1A receptors, alniditan (like 5-HT) was a full agonist for inhibition of stimulated adenylyl cyclase (IC50 = 1.1, 1.3, and 74 nM, respectively, for alniditan). Therefore, in functional assays, the potency of alniditan was much higher at 5-HT1D receptors than at 5-HT1A receptors. We further compared the properties of [3H]alniditan, as a new radioligand for 5-HT1D-type receptors, with those of [3H]5-HT in membrane preparations of calf substantia nigra, C6 glioma cells expressing h5-HT1D alpha, and L929 cells expressing h5-HT1D beta receptors. [3H]Alniditan revealed very rapid association and dissociation binding kinetics and showed slightly higher affinity (Kd = 1-2 nM) than [3H]5-HT. We investigated 25 compounds for inhibition of [3H]alniditan and [3H]5-HT binding in the three membrane preparations; Ki values of the radioligands were largely similar, although some subtle differences appeared. Most compounds did not differentiate between 5-HT1D alpha and 5-HT1D beta receptors, except methysergide, ritanserin, ocaperidone, risperidone, and ketanserin, which showed 10-60-fold higher affinity for the 5-HT1D alpha receptor. The Ki values of the compounds obtained with 5-HT1D receptors in calf substantia nigra indicated that these receptors are of the 5-HT1D beta-type. We demonstrated that alniditan is a potent agonist at h5-HT1D alpha and h5-HT1D beta receptors; its properties probably underlie its cranial vasoconstrictive and antimigraine properties.

Animals↗
PubMed1994

Sternitis and mediastinitis after coronary artery bypass grafting. Analysis of risk factors.

As part of a quality control program, we analyzed possible risk factors in the development of sternitis and mediastinitis after coronary artery bypass grafting. From 1 January 1990 through 31 December 1991, 1,368 consecutive coronary artery bypass grafting procedures were performed at our institution, either alone or in combination with other procedures. Twenty-three patients (1.7%) developed sternitis and/or mediastinitis; 7 (30.4%) of these patients died in an early postoperative phase. Univariate analysis revealed the following statistically significant (p < or = 0.05) risk factors: perfusion time, length of stay in operating room of longer than 5 hours 30 minutes, presence at the operation of a certain surgical resident, revision for bleeding, and postoperative mechanical ventilation lasting longer than 72 hours. After multivariate analysis, statistically significant independent risk factors were: diabetes mellitus, recent cigarette-smoking, reoperation, presence of a certain surgical resident at the operation, revision for bleeding, and length of mechanical ventilation of longer than 72 hours. The use of both internal thoracic arteries was not, in this study, shown to be an independent risk factor. We conclude that although the technique of using both internal thoracic arteries for myocardial revascularization carries no extra risk by itself in the development of sternitis or mediastinitis, associated factors such as prolonged stay in the operating room and reoperation could be responsible for a higher frequency of sternitis-mediastinitis in patients who have undergone this procedure. Therefore, it is advisable to use this technique selectively in high-risk patients. Close surveillance and reporting of wound infections is mandatory to detect risk factor related to the surgical staff (such as Staphylococcus aureus dissemination).

Aged↗
PubMed1984

On the maturation order of AML cells: a distinction on the basis of self-renewal properties and immunologic phenotypes.

To investigate the heterogeneous cellular structure of human acute myeloid leukemia (AML), subpopulations of cells were distinguished by two combined criteria: proliferation and differentiation. Purified blast cells were fractionated from blood or bone marrow of patients with newly diagnosed AML and colonies and clusters grown in phytohemagglutinin (PHA)-leukocyte feeder cultures. Large colonies, small colonies, macroclusters, and microclusters were recloned separately to assess the replicative capacities as a function of clone size. Large colonies showed higher proliferative capacities than did small ones, etc. Anti-Ia and an antigranulocyte (B4.3) monoclonal antibody (MoAb) were then employed to evaluate the stage of differentiation of AML cells in two patients before and following colony culture. Alterations of the immunologic phenotypes appeared during colony formation. This suggested differentiation of cells to more mature B4.3 granulocyte antigen-positive stages. MoAb-dependent cell lysis with the two antibodies was subsequently performed to assess the phenotypes of the precursors of the colonies and clusters. Leukemic colony-forming cells were Ia-positive and B4.3-negative and different from cluster-forming cells, which were largely Ia-negative and B4.3-negative. These data suggest that the cell organization of AML fits a maturation scheme containing immature cells with relatively high proliferative capacities, intermediate cells with low proliferative capacities, and end cells that are nonreplicative, and each with specific phenotypes.

Adult↗
PubMedDate not supplied

Lyme disease in Belgium.

A sero-epidemiological clinical and risk-group study was performed in Belgian Military men with a home-made Elisa kit, with the N34 Bb strain kindly provided by Prof. Ackermann Cologne. In the sero-epidemiological group the seroprevalence (age 18-28 years) was 3.2% In the clinical group the results were correlating to the serological and clinical data. In the risk group 44% were IgG positive. In conclusion the exposure of a standard Belgian young male population is low. (Overall IgG seropositivity 3.2%) (Total N = 1,916).

Adolescent↗