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Biomedical subjects

C Andrieux

Publications and source records attributed to C Andrieux.

At least 19 recordsLinked to original sources
PubMed2004

Prospective, randomized, parallel-group trial to evaluate the effects of lactulose and polyethylene glycol-4000 on colonic flora in chronic idiopathic constipation.

BACKGROUND: Although lactulose and polyethylene glycol are osmotic laxatives widely used in the treatment of chronic constipation, no study has been conducted to compare their actions on the colonic bacterial ecosystem, which has an important influence on host health. AIM: To assess the effects of lactulose and polyethylene glycol on the composition and metabolic indices of the faecal flora in patients with chronic idiopathic constipation. METHODS: Sixty-five patients with chronic idiopathic constipation were included in this controlled, multi-centre, randomized, parallel-group study. Participants received lactulose (Duphalac) or polyethylene glycol-4000 (Forlax) powders for the first week at a fixed dosage at night (20 g/day); in the second week, patients were given the option to vary the dose according to efficacy and tolerance (10-30 g/day); for the last 2 weeks, treatment was administered at a fixed dosage based on the results of the second week (10-30 g/day). Stools were recovered for bacteriological analysis at days -1, 21 and 28. RESULTS: Clinical efficacy and tolerance were similar with both treatments. In the lactulose group, an increase in faecal bifidobacteria counts (P = 0.04) and beta-galactosidase activity (P < 0.001) was observed from day -1 to day 28, whereas, in the polyethylene glycol group, there was a decrease in total short-chain fatty acids (P = 0.02), butyrate (P = 0.04), acetate (P = 0.02) and faecal bacterial mass (P = 0.001). No differences were observed in stools with regard to the following parameters: counts of Lactobacillus, clostridial spores, Bacteroides and enterobacteria, pH, biliary acids and neutral sterol concentrations. CONCLUSIONS: Both lactulose and polyethylene glycol are efficacious and well tolerated. However, although lactulose can be considered as a pre-biotic in constipated patients, polyethylene glycol produces signs of decreased colonic fermentation in the stool.

Bile Acids and Salts↗
PubMed2002

Metabolic characteristics of the faecal microflora in humans from three age groups.

BACKGROUND: Little is known about the influence of the ageing process on the bacterial metabolism. The aim of this work was to study the inter-individual variation and the influence of age on metabolic characteristics of the faecal microflora from persons of three age groups. METHODS: Nine enzyme activities and 11 metabolites were analysed in faecal samples of 21 elderly persons (69-89 years of age), 15 adults (30-46 years of age) and 14 children (3-15 years of age). RESULTS: They provide a pattern of the faecal microflora metabolism in a French population aged between 3 and 89 years. They showed large inter-individual differences in the three groups. Although the enzyme activities were not significantly different between groups, glycolytic activities appeared less variable in adults than in elderly persons and children. The major metabolites (acetate, propionate, butyrate and L-lactate) resulting from carbohydrate fermentation were similar in the three groups. Samples from elderly persons were characterized by higher D/L lactate ratio and higher concentrations of metabolites resulting from protein fermentation (ammonia, valerate, iso-butyrate and iso-valerate). CONCLUSION: The data showed significant differences between elderly persons and younger adults and children, but the major metabolic characteristics of the faecal microflora were not greatly altered by the ageing process.

Adolescent↗
PubMed2001

Differential influence of butyrate concentration on proximal and distal colonic mucosa in rats born germ-free and associated with a strain of Clostridium paraputrificum.

In vivo influence of butyrate in colonic mucosa was studied using a model of gnotobiotic rats monoassociated with a Clostridium paraputrificum. Rats were fed a diet containing increasing amounts of non-digestible carbohydrates, the fermentation of which led to modulated amounts of butyrate in the large intestine. In the proximal colon, the increase in the butyrate concentration alters crypt depth and the number of mucus-containing cells; the increase in butyrate was highly correlated with the number of neutral-mucin-containing cells. Conversely, in the distal colon, no relation was found between the increase in butyrate concentration and crypt depth or number of mucin-containing cells. In both the proximal and distal colon, the mitotic index remained unchanged. In conclusion, in vivo production of physiological quantities of butyrate had a trophic effect on proximal colonic mucosa, but did not influence the distal epithelium.

Animals↗
PubMed2001

Food supplementation with milk fermented by Lactobacillus casei DN-114 001 protects suckling rats from rotavirus-associated diarrhea.

Group A rotavirus is the leading cause of diarrhea among children aged 3-36 mo worldwide. Introducing fermented milk products into the infant diet has been proposed for the prevention or treatment of rotavirus diarrhea. The preventive effect of milk fermented by the Lactobacillus casei strain DN-114 001 was studied in a model of germfree suckling rats supplemented daily from d 2 of life and infected with SA11 rotavirus at d 5 (RF group). One group was supplemented with nonfermented milk (RM) and two uninfected groups (CM and CF) received either nonfermented or fermented milk. Frequency and severity of diarrhea were observed. Rats were killed at various times from 0 to 120 h postinfection (p.i.). Bacteria were measured in the intestine, and rotavirus antigens were detected by ELISA in fecal samples and in different parts of the intestine. Histologic observations were made, including vacuolation, morphology of intestinal villi and number of mucin cells. RM rats had diarrhea for 6 d; compared with the CM group, they had alterations of the intestinal mucosa characterized by cellular vacuolation 48 and 72 h p.i. and a lower number of sulfated mucin cells 72 and 96 h p.i. (P: < 0.05). Early supplementation with fermented milk significantly decreased the clinical signs of diarrhea from 24 to 144 h p.i. (P: < 0.05) and prevented rotavirus infection in all sections of the intestine. Histologic lesions of the small intestine were greatly reduced (P: < 0.05) and the number of mucin cells remained unchanged. The data are discussed with respect to the possibility of reducing rotavirus diarrhea in young children by consumption of fermented milk.

Animals↗
PubMed2001

Colonic delivery of sodium butyrate via oral route: acrylic coating design of pellets and in vivo evaluation in rats.

Few pharmaceutical studies, with the exception of those on rectal solutions, are described on short chain fatty acid (SCFA) formulations-especially for sodium butyrate, which is a colonocyte preferential substrate. Highly dosed butyrate pellets (90%) were prepared and their coating was designed for colonic delivery. In vivo determination (pH and transit time of pellets in rats) allowed to respectively choose the grade and thickness (resistance of 6 h) of the pH-dependent coating (Eudragi L+S, 1:1). The coated pellets were administered to naturally butyrate-deprived rats. The rats' colonic mucosa had the particularity to weakly express mitochondrial HMG-CoA synthase, an enzyme that responds to luminal butyrate. The results did not show early absorption of butyrate, but a probable cecal loss in the rat cecum as cecal residence time of the pellets was important and as pH was propitious for the coating hydrolysis. It seemed that butyrate, given daily for 7 days without the other main SCFA. was unable to induce the enzyme and/or that the dose (0.32 mmol/day) was insufficient.

Administration, Oral↗
PubMed1999

Gastrointestinal transit of pellets in rats: effect of size and density.

Gastrointestinal distribution kinetics of a large amount (0.5-1 g) of three types of non-disintegrating pellets which had the same size (S1, 710-1000 micrometers) but different densities (D1, 0.9 and D2, 1.5 g cm-3), or which had the same density (D1) but different diameters (S1 and S2, 1250-1600 micrometers) were examined in fed rats. The percentage of pellets remaining in the stomach, small gut, caecum and colon was measured at suitable intervals. Whatever the size of the pellets, the heavier the density, the longer the gastric emptying (2.1 h for D2-S1 instead of 1.3 h for D1-S1 and 0.7 h for D1-S2). The small gut transit time was not influenced by density but was slightly prolonged by size: 3.3 h for D1-S2 instead of 2.6 h for D1-S1 and D2-S1. Conversely, the gastrocolonic transit time was widely influenced by density (13.5 h for D2-S1) and somewhat by size (8.2 h for D1-S2 and 4.5 h for D1-S1). This delays were proportional to caecal residence time in the large, sacculated and derivated caecum of rats. In order to use the rat as an experimental model for pharmaceutical pellets, those results should have implication for the design of dosage forms, particularly those for controlled or timed release or those for targeted release at specific positions in the gastrointestinal tract.

Animals↗
PubMed1999

Variation of mucin distribution in the rat intestine, caecum and colon: effect of the bacterial flora.

The influence of the intestinal microflora on mucin types was studied in the small intestine, caecum and colon of conventional (CV) rats as compared to germ-free (GF) rats. A colorimetric method was used on purified water-soluble mucin extracted from mucosal scrapings and contents. Variations occurred between the three anatomical sites both in the mucosas and intestinal contents of GF rats. In CV rats, the presence of the bacterial flora led to different effects depending on the intestinal site: in the small intestinal mucosa, neutral and sulphomucins values were higher whereas sialomucin was much lower. Conversely, sialomucin was higher in the caecal and colonic mucosas and contents whereas sulphated mucins were decreased significantly in caecal contents and caecal and colonic mucosas. These variations in the contents may reflect the bacterial mucolytic activity and the effect of bacterial metabolites on the mucosa.

Animal Feed↗
PubMed1998

Release of the soluble co-receptor (protein Fv) of secretory immunoglobulins after colonization of axenic rats by the human gut microflora.

The presence of protein Fv (pFv), a soluble co-receptor of human gut antibodies, was investigated in heteroxenic rats as a function of the presence of the human digestive microflora. This endogenous molecule was not detected in the stools of axenic rats but was found in those of heteroxenic animals. The release was delayed for 1 week after colonization and found to be independent from the kinetics of bacteria-induced short-chain fatty acids issued from the catabolism of carbohydrates and of proteins. The similar bacterial composition of pFv-positive and of pFv-negative stools, and the lack of induction by different dominant bacterial genera, suggest that non-dominant species must be involved. These results indicate that human colonic flora is a major inducer of pFv and thus participates in increasing the efficiency of the intestinal immunity by this additional mechanism known to maintain and augment the polymeric status of secretory immunoglobulin (Ig)A.

Animals↗
PubMed1998

Milk fermented with yogurt cultures and Lactobacillus casei compared with yogurt and gelled milk: influence on intestinal microflora in healthy infants.

Ingestion of fermented dairy products induces changes in the equilibrium and metabolism of the intestinal microflora and may thus exert a healthful influence on the host. We compared the effects of consumption of a traditional yogurt, a milk fermented with yogurt cultures and Lactobacillus casei (YC), and a nonfermented gelled milk on the fecal microflora of healthy infants. Thirty-nine infants aged 10-18 mo were randomly assigned to one of three groups in which they received 125 g/d of one of the three products for 1 mo. The following indexes were not modified during the supplementation period or for 1 wk after the end of supplementation: total number of anaerobes, bifidobacteria, bacteroides, and enterobacteria; pH; water content; concentrations of acetate, butyrate, propionate, and lactate; and bacterial enzyme activity of beta-galactosidase and alpha-glucosidase. In contrast, in the yogurt group the number of enterococci in fecal samples increased (P < 0.05), whereas the percentage of branched-chain and long-chain fatty acids, which are markers of proteolytic fermentation, decreased (P < 0.05). In the YC group, the percentage of children with > 6 log10 colony-forming units lactobacilli/g feces increased (P < 0.05), whereas the potentially harmful enzyme activity of beta-glucuronidase and beta-glucosidase decreased (P < 0.05). These decreases were particularly marked in those infants in the YC group in whom activity of the enzymes was initially unusually high.

Animals↗
PubMed1998

Physiological effects of a pea protein isolate in gnotobiotic rats: comparison with a soybean isolate and meat.

Pea proteins have been considered for the introduction into the human diet only recently. This protein source was tested on nutritional and digestive parameters in heteroxenic male Fischer rats inoculated with a human faecal microflora from a methane producer. Compared to soybean proteins, pea proteins have similar effects on the rat's endogenous and bacterial digestive patterns. Compared to the pea proteins, a diet containing a standard meat meal enhanced the pH and the production of ammonia, while a lyophilized beef meat enhanced that of urea. The diet containing the standard meat decreases short-chain fatty acids and modifies the ratio of caecal short-chain fatty acids. Both animal diets decreased the specific activities of pancreatic proteases such as chymotrypsin (EC 3.4.21.1), trypsin (EC 3.4.21.4), and carboxypeptidase A (EC 3.4.17.1) when compared to the diet containing the pea isolate. In conclusion, the whole composition of the diet, more than the origin of the dietary protein, influences the rat's digestive pattern.

Animal Nutritional Physiological Phenomena↗
PubMed1997

Compared effects of three oligosaccharides on metabolism of intestinal microflora in rats inoculated with a human faecal flora.

Using germ-free rats inoculated with a human faecal flora (gnotobiotic rats), the effects of three oligosaccharides (beta-fructo-oligosaccharides (FOS), beta-galacto-oligosaccharides (TOS) and alpha-gluco-oligosaccharides (GOS)) on intestinal bacterial metabolism were compared. The animals were fed on either a control diet or diets containing 40 g/kg of GOS, FOS or TOS. FOS and TOS were the preferred growth substrates for Bifidobacteria which increased in number by 2 log values in faeces of rats when compared with rats fed on GOS or control diets. Ingestion of TOS specifically induced hydrolysis of the substrate, and did not modify the activity of any other enzymes measured in the caecum. GOS led to a non-specific enzymic induction of beta-galactosidase (EC 3.2.1.23), beta-glucosidase (EC 3.2.1.21) and alpha-glucosidase (EC 3.2.1.20) activities whereas beta-glucuronidase (EC 3.2.1.31) was lowered. Compared with the control group, FOS and TOS diets led to a significant increase in H2 and CH4 excretion; the GOS diet increased only CH4. Analysis of caecal contents revealed a decrease in pH for all diets compared with controls. Total short-chain fatty acid (SCFA) concentration increased significantly in all groups, but the SCFA profile differed between treatment groups. It was concluded that the three oligosaccharides studied had different effects which may be linked to their chemical structure. Some of these effects may be beneficial to human health.

Animals↗
PubMed1997

The association of yogurt starters with Lactobacillus casei DN 114.001 in fermented milk alters the composition and metabolism of intestinal microflora in germ-free rats and in human flora-associated rats.

The aim of this study was to compare the effects of milk and of various fermented milks on the composition and metabolic activities of the intestinal microflora. Groups of eight rats were fed for 6 wk a diet containing 30% nonfermented milk (M), yogurt (Y), milk fermented with Lactobacillus casei (LcFM) or milk fermented with the association of L. casei DN 114.001 and yogurt starters (LcYFM). In the first study, the survival of the lactic acid bacteria from the fermented milks was assessed by bacterial enumeration in feces of germ-free rats (GF rats) fed milk or fermented milks. The metabolic activities of the lactic acid bacteria were studied in these rats by the measurement of glycolytic activities and products of bacterial fermentation, i.e., acetate and lactate (isoforms L and D). In a second study, the effects of fermented milks on the composition and metabolism [gas, glycolytic activities, short-chain fatty acids (SCFA), alcohol and ammonia] of human flora were studied using human flora-associated rats (HF rats). In GF rats, the survival of L. casei in the feces did not differ between those fed the LcFM and LcYFM diets. L. bulgaricus was detected in the feces of the rats fed Y, whereas Streptoccus thermophilus was found in the feces of the LcYFM group. In HF rats, fecal concentration of Bifidobacteria was greater in the LcFM group than in the others. beta-Glucuronidase (EC 3.2.1.31) activity was lower in rats fed LcFM and Y than in those fed M and LcYFM, whereas beta-galactosidase (3.2.1.23), alpha-glucosidase (EC 3.2.1 20) and beta-glucosidase (EC 3.2.1.21) activities were higher in the LcYFM group compared with the others. Methane excretion was higher in rats fed Y than in other groups. Cecal SCFA concentrations did not differ in LcFM, Y and M groups, but total SCFA, acetate, propionate and butyrate were significantly greater in the LcYFM group. These results suggest that milk fermented with the combination of L. casei and yogurt starters leads to specific effects that are different from the simple addition of the effects found with yogurt and milk fermented with L. casei. These specific effects are potentially beneficial to human health.

Acetates↗
PubMed1997

Pattern of metabolism and composition of the fecal microflora in infants 10 to 18 months old from day care centers.

BACKGROUND: From 5 months of age, infants are progressively introduced to a variety of foods which influence the equilibrium of the intestinal microflora. METHODS: Thirty-five children age 10-18 months from 8 day care centers in France were studied. Fecal specimens were examined for their biochemical and microbiological criteria. RESULTS: Bifidobacteria and Bacteroides belong to the predominant populations (9.7 and 8.6 log 10 cfu/g, respectively). The mean level of enterobacteria and enterococci were 8.0 and 7.8 log 10 cfu/g, respectively. Only 10% of the infants presented a lactobacilli amount above 6 log 10 cfu/g. Most feces had similar pH values (mean 6.4), percentage of water (mean 76.4%), and short chain fatty acid, ammonia and lactic acid concentrations (means 77, 6.7 and 2.3 mumol/g, respectively). beta-galactosidase had the highest activity (106 IU/g of protein) and nitroreductase, the lowest (0.1 IU/g of protein). alpha-glucosidase and nitrate reductase showed intermediate values of 17 and 4 IU/g of protein, respectively. With the exception of 4 infants, beta-glucosidase and beta-glucuronidase values were low (4 and 2 IU/g of protein). Age and day care center were not significant factors for most parameters studied, except that rotavirus was related to day care center, with detection in 5 infants from the same center. CONCLUSIONS: Many biochemical parameters were comparable to those found in adults, with the exception of ammonia concentration and beta-galactosidase activity. The fecal bacterial profile was different than in adults, with more Bifidobacteria than Bacteroides and higher levels of facultative anaerobes. One infant suffering from gastroenteritis had distinctive biochemical and bacterial parameters.

Ammonia↗
PubMed1996

Intestinal mucin distribution in the germ-free rat and in the heteroxenic rat harbouring a human bacterial flora: effect of inulin in the diet.

A colorimetric method was used on water-soluble mucin extracted from mucosal scrapings and contents of the caecum and the colon of five germ-free (GF) rats and five heteroxenic (HE) rats harbouring a human flora (GF rats associated with a human flora). These rats were fed on a diet containing either 100 g sucrose/kg or 100 g inulin/kg. Histological stains, periodic acid-Schiff, alcian blue pH 2.5 and alcian blue pH 0.5 were used to discriminate between neutral, acidic and acidic sulphated mucins respectively. Spectrocolorimetric assays led to a calculated absorbance value for 1 mg of the initial mucin extract. Each mucin type was compared between treatments. The caecal contents of GF rats contained more acidic mucin than sulphomucin, which was present in the same proportion as neutral mucin. Their colonic contents contained more acidic mucins than sulphomucin, which in turn was more abundant than neutral mucin. Their caecal mucosa mucin distribution differed from that of the contents: very little acidic mucin was present and neutral and sulphomucin proportions were of the same order of magnitude. Inulin increased the amount of neutral mucin in the caecal contents and of sulphated mucins in the colonic contents and increased the amounts of neutral and acidic mucins in the caecal mucosa. Mucin distribution in the HE rats was very different from that in the GF rats: the caecal contents contained a high proportion of acidic mucins and very little sulphomucin. The same distribution of mucins was observed in the colonic contents. The caecal mucosa contained less acidic mucin and more sulphomucin than the caecal contents. Inulin decreased acidic mucins and increased sulphated mucins in the caecal contents and increased neutral and sulphated mucins in the colonic contents. Inulin increased sulphomucin in the caecal mucosa and decreased acidic mucin in the caecal and colonic mucosas. The very low amount of mucin that was recovered in the colonic mucosa suggests that, in the presence of the bacterial flora and associated with inulin in the diet, mucin was extensively released from the mucosa to the colonic lumen. This might be related to the bacterial metabolites produced.

Animals↗
PubMed1996

Effect of two levels of transgalactosylated oligosaccharide intake in rats associated with human faecal microflora on bacterial glycolytic activity, end-products of fermentation and bacterial steroid transformation.

The effects of two levels of transgalactosylated oligosaccharide (TOS) intake on bacterial glycolytic activity, end products of fermentation and bacterial steroid transformation were studied in rats associated with a human faecal flora. Rats were fed a human-type diet containing 0, 5 or 10% TOS. Caecal pH decrease correlated with the amount of TOS in the diet. Intake of the TOS diet induced a decrease in blood cholesterol and a strong increase in beta-galactosidase activity in the hindgut. TOS fermentation led to production of hydrogen and short chain fatty acids, whereas ammonia and branched-chain fatty acids were decreased. A diet containing 10% TOS increased caecal lactic acid concentrations and reduced beta-glucuronidase activities and steroid transformation.

Animals↗
PubMed1996

Effects of Bifidobacterium sp fermented milk ingested with or without inulin on colonic bifidobacteria and enzymatic activities in healthy humans.

OBJECTIVE: To assess in healthy humans the effects of prolonged ingestion of Bifidobacterium sp fermented milk (BFM) with or without inulin on fecal bifidobacteria and some bacterial enzymatic activities. DESIGN: Twelve volunteers randomly divided into two groups were studied for three consecutive periods. During the ingestion period, they received BFM in association with ether 18g/d inulin or placebo in three oral doses for 12 days. Stools were regularly collected for bacteriological analysis. SETTING: Clinical Nutrition Unit, Hopital Saint-Lazare, Paris. RESULTS: The administration of BFM with placebo led to an increase in total bifidobacteria (indigenous and exogenous) (P < 0.01) and exogenous bifidobacteria (P < 0.01) and a decrease in beta-glucuronidase activity (P < 0.01). Simultaneous administration of BFM and inulin led to an increase in total bifidobacteria (P < 0.01) and exogenous bifidobacteria (P < 0.01), but had no effect on beta-glucuronidase activity. No differences were found for fecal concentrations reached by exogenous and indigenous bifidobacteria between the two groups. Administrated alone or with inulin, BFM did not change fecal total anaerobe counts, pH, nitrate reductase, nitroreductase and azoreductase activities. CONCLUSIONS: Administration of BFM substantially increases the proportion of bifidobacteria in the colonic flora, but the concurrent administration of inulin does not enhance this effect.

Adult↗
PubMed1995

Comparative study of the fermentative characteristics of inulin and different types of fibre in rats inoculated with a human whole faecal flora.

It is known that the physico-chemical characteristics of fibre modify their fermentation characteristics in the colon. Previously we showed the varying effects of inulin and different types of fibre on the hepatic and intestinal xenobiotic-metabolizing enzymes (XME) in initially germ-free rats inoculated with a human, methanogenic, whole-faecal flora (Roland et al. 1994). The aim of the present work was to assess whether or not these effects could be related to differences in production of fermentation metabolites (gases excreted in vivo and caecal metabolites) due to the different compositions of fibre. The different types of fibres were analysed with regard to their solubility and their composition of neutral monomers and uronic acids. Inulin was totally soluble, carrot (Daucus carota), cocoa (Theobroma cacao) and wheat bran were partially soluble; pea (Pisum sativum) and oat were nearly totally insoluble. Uronic acids were found mostly in carrot and cocoa fibre. Glucose was present as the main neutral monomer in each fibre type. Xylose was found also in wheat bran, pea and oat fibres, and arabinose was found in wheat bran. Inulin consumption led to high levels of H2 production but no CH4 production, to a 4-fold greater caecal concentration of butyrate than with the other fibres and to a decrease in caecal pH. Conversely, rats fed on carrot or cocoa fibre produced a large amount of CH4 but no H2 and generated a different profile of short-chain fatty acids (SCFA). The lowest amounts of gases and SCFA were found in rats fed on wheat bran, pea and oat fibre. We observed a relationship between the caecal concentration of SCFA and the activity of hepatic glutathione-S-transferase (EC 2.5.1.18) but no direct link was shown between the other XME and the fermentation profile.

Animals↗