Página 1 dos resultados de 113 itens digitais encontrados em 0.141 segundos

‣ Intestinal mucosa-associated microflora in ulcerative colitis patients before and after restorative proctocolectomy with an ileoanal pouch

ALMEIDA, Maristela G.; KISS, Desiderio R.; ZILBERSTEIN, Bruno; QUINTANILHA, Alina G.; TEIXEIRA, Magaly G.; HABR-GAMA, Angelita
Fonte: LIPPINCOTT WILLIAMS & WILKINS Publicador: LIPPINCOTT WILLIAMS & WILKINS
Tipo: Artigo de Revista Científica
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PURPOSE: This study was designed to identify the mucosa-associated microflora in patients with severe ulcerative colitis before and after restorative proctocolectomy with ileoanal pouch construction in comparison with historic controls. METHODS: Ten patients with a diagnosis of ulcerative colitis were evaluated. Mucus was collected during colonoscopy from all segments of the colon and terminal ileum before surgery, and from the ileal pouch two and eight months after ileostomy closure. The prevalence and mean concentration of the mucosa-associated microflora were compared over time and with historic controls. RESULTS: Veillonella sp was the most prevalent bacterium in patients and controls. Klebsiella sp was significantly more prevalent in the ileum of controls, was not found in patients with ulcerative colitis, and after proctocolectomy returned to values found in controls. Some bacteria such as Enterobacter sp, Staphylococcus sp (coag-), Bacteroides sp (npg), Lactobacillus sp, and Veillonella sp had higher mean concentrations in the ileal pouch of patients after surgery than in controls. CONCLUSION: No bacterium was identified that could be exclusively responsible for the maintenance of the inflammatory process. The mucosa-associated microflora of patients with ulcerative colitis underwent significant changes after proctocolectomy with ileal pouch construction and returned to almost normal values for some bacteria.

‣ Decreased expression of mannose-specific adhesins by Escherichia coli in the colonic microflora of immunoglobulin A-deficient individuals.

Friman, V; Adlerberth, I; Connell, H; Svanborg, C; Hanson, L A; Wold, A E
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1996 Português
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Most Escherichia coli isolates can express type 1 fimbriae with mannose-specific adhesins. These adhesins bind to the oligosaccharide chains of secretory immunoglobulin A (IgA). Thus, in addition to specific antibody activity, secretory IgA possesses a broad reactivity with bacteria expressing type 1 fimbriae. The absence of secretory IgA in colonic secretions, as seen in IgA deficiency, might therefore alter the ability of type 1-fimbriated E. coli to colonize the large intestines of these individuals. In the present study, 10 E. coli isolates from each of 17 IgA-deficient and 17 age-matched control individuals were assessed for the carriage of the fim gene cluster by DNA-DNA hybridization and for the expression of type 1 fimbriae by hemagglutination of guinea pig erythrocytes. The contribution of type 1-fimbria-mediated adherence to HT-29 colonic cells was also analyzed. The proportion of fim+ E. coli isolates was lower in IgA-deficient than in control individuals (74 versus 94%, P < 0.05), as was the proportion of isolates expressing type 1 fimbriae in vitro (69% versus 85%, P < 0.05). The median mannose-sensitive adherence to HT-29 cells was lower for isolates from IgA-deficient individuals than from the controls (9 versus 26 bacteria per cell...

‣ Comparative effects of enoxacin and norfloxacin on human colonic microflora.

Edlund, C; Lidbeck, A; Kager, L; Nord, C E
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1987 Português
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Ten healthy volunteers received 400 mg of enoxacin and another ten healthy volunteers received 200 mg of norfloxacin orally twice a day for 7 days. Fecal specimens were collected before, during, and after drug administration to study the impact of enoxacin and norfloxacin on the normal colonic microflora. On day 7, the mean concentrations of enoxacin and norfloxacin were 350 and 950 mg/kg of feces, respectively. Enoxacin and norfloxacin affected the colonic microflora in similar ways. The number of strains of the family Enterobacteriaceae was markedly suppressed during drug administration, whereas the gram-positive and anaerobic microfloras were not significantly altered. Two weeks after withdrawal of the drugs, the colonic microflora had returned to normal.

‣ Role of competition for nutrients in suppression of Clostridium difficile by the colonic microflora.

Wilson, K H; Perini, F
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1988 Português
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The cecal flora of mice is able to eliminate Clostridium difficile from the mouse cecum even when C. difficile is the first organism established. We used a continuous-flow (CF) culture model of the cecal flora to investigate the possibility that competition for nutrients is one mechanism for this antagonism. The medium for the CF cultures consisted of homogenates of fecal pellets from germfree mice. Carbohydrate analysis showed that mouse flora depleted 74 to 99.8% of the various carbohydrates from this environment-simulating medium. When inoculated into filtrates made from CF cultures of mouse flora, C. difficile multiplied slower than the dilution rate of the CF cultures unless glucose, N-acetylglucosamine, or N-acetylneuraminic acid was added. C. difficile did not synthesize hydrolytic enzymes able to cleave these monosaccharides from oligosaccharide side chains. As found previously, veal infusion broth did not support the growth of a microflora that could be transferred to gnotobiotic mice and fully suppress C. difficile. When mucin or monosaccharides found in mucin were added to veal infusion broth, the flora functioned normally in this regard. These data suggest that as yet unidentified organisms compete more efficiently than C. difficile for monomeric glucose...

‣ Suppression of colonic microflora by cefoperazone and evaluation of the drug as potential prophylaxis in bowel surgery.

Silva, M; Cornick, N A; Gorbach, S L
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1989 Português
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We evaluated the activity of cefoperazone (CPZ) on the intestinal flora in terms of its use as a single prophylactic drug in colon surgery. Twenty-four healthy male volunteers between the ages of 20 and 40 were assigned to receive either CPZ, oral neomycin-erythromycin, or no antibiotics. A mechanical bowel preparation, Golytely, was also given to each of the subjects. With intravenous CPZ, antibiotic levels in the stool ranged from less than 2 to 649 micrograms/ml and the total fecal bacterial counts dropped 3 to 4 log10 CFU/g. Higher levels of CPZ were detected in the stools when an oral dose was added, 1,446 to 5,445 micrograms/ml, and the bacterial counts were reduced maximally 4 to 6 log10 CFU/g. The combination of the oral and intravenous doses produced suppression of the microflora and high levels in blood, all with a single antibiotic.

‣ Comparison of the fecal microflora of Seventh-Day Adventists with individuals consuming a general diet. Implications concerning colonic carcinoma.

Goldberg, M J; Smith, J W; Nichols, R L
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1977 Português
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Qualitative and quantitative fecal microflora was studied in a double blind fashion in 28 subjects. Fourteen were Seventh-Day Adventists, who were strict vegetarians, while the remaining 14 subjects were individuals consuming a general western diet. No statistically significant differences were identified in the fecal microflora of the two groups. The bacteriologic analysis included total aerobes and total anaerobes as well as each of the major fecal aerobes and anaerobes. This study seems to indicate that the dietary intake of animal fat and protein does not significantly alter the fecal microflora, a possibility which has previously been suggested as being part of the explanation for the higher incidence of colonic carcinoma in those who consume meat compared with vegetarians. It does not, however, invalidate the concept that dietary animal fat does increase bile acid degradation within the gastrointestinal tract, a factor which has been related to colon cancer. Future studies should be directed at identifying the factors that may be present in the gastrointestinal tracts of vegetarians which modify the ability of their colonic microflora to degrade bile acids, an essential step in the production of intraluminal carcinogens or co-carcinogens.

‣ Impairment of the Intestinal Barrier by Ethanol Involves Enteric Microflora and Mast Cell Activation in Rodents

Ferrier, Laurent; Bérard, Florian; Debrauwer, Laurent; Chabo, Chantal; Langella, Philippe; Buéno, Lionel; Fioramonti, Jean
Fonte: American Society for Investigative Pathology Publicador: American Society for Investigative Pathology
Tipo: Artigo de Revista Científica
Publicado em /04/2006 Português
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Alcohol hepatic toxicity in heavy drinkers is associated with high endotoxin blood levels and increased intestinal permeability. Because endotoxins can cross damaged mucosa, we investigated the mechanisms through which ethanol impairs the colonic epithelium of rats submitted to acute alcohol intake. Colonic permeability to 51Cr-ethylenediamintetraacetic acid was increased 24 hours after 3.0 g/kg ethanol intake (3.2 ± 0.2% versus 2.2 ± 0.2%) and was associated with significant endotoxemia. Antibiotics and doxantrazole (a mast cell membrane stabilizer) significantly inhibited the effect of ethanol. Two hours after intake, plasma concentrations of ethanol were twofold higher in antibiotic-treated rats than in controls (155.8 ± 9.3 mg/dl versus 75.7 ± 7.6 mg/dl, P < 0.001). Lumenal concentrations of acetaldehyde were markedly increased after ethanol intake (132.6 ± 31.6 μmol/L versus 20.8 ± 1.4 μmol/L, P < 0.05) and antibiotics diminished this increase (86.2 ± 10.9 μmol/L). In colonic samples mounted in Ussing chambers, acetaldehyde but not ethanol increased dextran flux across the mucosa by 54%. Doxantrazole inhibited the effect of acetaldehyde. This study demonstrates that an acute and moderate ethanol intake alters the epithelial barrier through ethanol oxidation into acetaldehyde by the colonic microflora and downstream mast cell activation. Such alterations that remain for longer periods could result in excessive endotoxin passage...

‣ Bifidobacterium strains from resident infant human gastrointestinal microflora exert antimicrobial activity

Lievin, V; Peiffer, I; Hudault, S; Rochat, F; Brassart, D; Neeser, J; Servin, A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/2000 Português
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BACKGROUND AND AIMS—The gastrointestinal microflora exerts a barrier effect against enteropathogens. The aim of this study was to examine if bifidobacteria, a major species of the human colonic microflora, participates in the barrier effect by developing antimicrobial activity against enterovirulent bacteria.
METHODS—Antibacterial activity was examined in vitro against a wide range of Gram negative and Gram positive pathogens. Inhibition of Salmonella typhimurium SL1334 cell association and cell invasion was investigated in vitro using Caco-2 cells. Colonisation of the gastrointestinal tract in vivo by bifidobacteria was examined in axenic C3/He/Oujco mice. Antimicrobial activity was examined in vivo in axenic C3/He/Oujco mice infected by the lethal S typhimurium C5 strain.
RESULTS—Fourteen human bifidobacterium strains isolated from infant stools were examined for antimicrobial activity. Two strains (CA1 and F9) expressed antagonistic activity against pathogens in vitro, inhibited cell entry, and killed intracellular S typhimurium SL1344 in Caco-2 cells. An antibacterial component(s) produced by CA1 and F9 was found to be a lipophilic molecule(s) with a molecular weight of less than 3500. In the axenic C3/He/Oujco mice...

‣ Effects of treatment with antimicrobial agents on the human colonic microflora

Rafii, Fatemeh; Sutherland, John B; Cerniglia, Carl E
Fonte: Dove Medical Press Publicador: Dove Medical Press
Tipo: Artigo de Revista Científica
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Antimicrobial agents are the most valuable means available for treating bacterial infections. However, the administration of therapeutic doses of antimicrobial agents to patients is a leading cause of disturbance of the normal gastrointestinal microflora. This disturbance results in diminishing the natural defense mechanisms provided by the colonic microbial ecosystem, making the host vulnerable to infection by commensal microorganisms or nosocomial pathogens. In this minireview, the impacts of antimicrobials, individually and in combinations, on the human colonic microflora are discussed.

‣ The Effects of Maturation on the Colonic Microflora in Infancy and Childhood

Enck, P.; Zimmermann, K.; Rusch, K.; Schwiertz, A.; Klosterhalfen, S.; Frick, J. S.
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
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The composition of colonic mircoflora and its changes with maturation have rarely been investigated in large samples. Methods. We used conventional microbiological testing to analyse the colonic flora (Kyberstatus, Institut forMicroecology, Herborn, Germany) of stool samples from 12 484 children with different intestinal and nonintestinal diagnoses. Stool samples were analysed for total colony forming units (CFU) (per g stool) and the abundance of Bifidobacteria, Bacteroides sp., Escherichia coli, Enterococcus sp., and Lactobacillus sp. with respect to age, gender. A subset of 1089 infants was analysed for monthly changes within the first year of life. Results. Total CFU and individual microbial species were highest during the first year of life, decreased within the first 2 years, and then stabilized for the remaining childhood. In infants, the total CFU rose until month 5, declined with weaning, and peaked at 9–10 months. Significant effects of age, but not of gender, were found in Bacteroides sp. and Lactobacilli. However Bacterioids sp. and Lactobacilli increased with age, while Enterococci and E. coli decreased, and Bifidobacteria remained stable. Conclusion. Colonic microflora show both a bacteria-specific and general pattern of maturation which is most profound within the first year.

‣ P fimbriae, capsule and aerobactin characterize colonic resident Escherichia coli.

Nowrouzian, F.; Adlerberth, I.; Wold, A. E.
Fonte: Cambridge University Press Publicador: Cambridge University Press
Tipo: Artigo de Revista Científica
Publicado em /02/2001 Português
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Resident and transient Escherichia coli strains from the colonic microflora of 13 Swedish schoolgirls were analysed for carriage of genes encoding a range of adhesins (P, type 1 and S fimbriae, Dr haemagglutinin and three varieties of the P fimbrial papG adhesin) and other virulence traits (K1 and K5 capsule, haemolysin and aerobactin) using multiplex PCR. Forty-four percent of the resident clones carried genes for P fimbriae, K1 or K5 capsule, and aerobactin, compared with only 3% of transient clones (P < 0.0001). The P-fimbriated clones most often had the class II variety of the P-fimbrial adhesin gene papG and this adhesin was significantly associated with persistence of a strain. S fimbriae and type 1 fimbriae were equally common in resident and transient strains. The results indicate that not only P fimbriae, but also, certain capsules and the ability to produce the siderophore aerobactin might contribute to persistence of E. coli in the large intestine.

‣ The Interaction of Large Bowel Microflora with the Colonic Mucus Barrier

Pearson, Jeffrey P.; Brownlee, Iain A.
Fonte: SAGE-Hindawi Access to Research Publicador: SAGE-Hindawi Access to Research
Tipo: Artigo de Revista Científica
Publicado em 03/10/2010 Português
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The colonic mucus barrier is the first line of defence that the underlying mucosa has against the wide range of potentially damaging agents of microbial, endogenous, and dietary origin that occur within the colonic lumen. The functional component of mucus is the secreted, polymeric glycoprotein mucin. The mucus barrier can either act as an energy source or a support medium for growth to the intestinal microflora. The mucus barrier appears to effectively partition the vast number of microbial cells from the underlying epithelium. The normal functionality and biochemistry of this mucus barrier appears to be lost in diseases of the colorectal mucosa. Germ-free animal studies have highlighted the necessity of the presence of the colonic microflora to drive the maturation of the colonic mucosa and normal mucus production. A number of by-products of the microflora have been suggested to be key luminal drivers of colonic mucus secretion.

‣ Urolithins, Ellagic Acid-Derived Metabolites Produced by Human Colonic Microflora, Exhibit Estrogenic and Antiestrogenic Activities

Larrosa, Mar; González-Sarrías, Antonio; García-Conesa, María Teresa; Tomás Barberán, Francisco; Espín de Gea, Juan Carlos
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artículo Formato: 259768 bytes; application/pdf
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10 pages, 8 figures, 1 table.; Urolithins A and B (hydroxy-6H-dibenzo[b,d]pyran-6-one derivatives) are colonic microflora metabolites recently proposed as biomarkers of human exposure to dietary ellagic acid derivatives. Molecular models suggest that urolithins could display estrogenic and/or antiestrogenic activity. To this purpose, both urolithins and other known phytoestrogens (genistein, daidzein, resveratrol, and enterolactone) were assayed to evaluate the capacity to induce cell proliferation on the estrogen-sensitive human breast cancer MCF-7 cells as well as the ability to bind to α- and β-estrogen receptors. Both urolithins A and B showed estrogenic activity in a dose-dependent manner even at high concentrations (40 μM), without antiproliferative or toxic effects, whereas the other phytoestrogens inhibited cell proliferation at high concentrations. Overall, urolithins showed weaker estrogenic activity than the other phytoestrogens. However, both urolithins displayed slightly higher antiestrogenic activity (antagonized the growth promotion effect of 17-β-estradiol in a dose-dependent manner) than the other phytoestrogens. The IC50 values for the ERα and ERβ binding assays were 0.4 and 0.75 μM for urolithin A; 20 and 11 μM for urolithin B; 3 and 0.02 for genistein; and 2.3 and 1 for daidzein...

‣ Identification of Urolithin A as a Metabolite Produced by Human Colon Microflora from Ellagic Acid and Related Compounds

Cerdá, Begoña; Periago, Paula María; Espín de Gea, Juan Carlos; Tomás Barberán, Francisco
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artículo Formato: 259768 bytes; application/pdf
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6 pages, 3 tables, 4 figures.; Dietary ellagic acid and related polyphenols are metabolized in humans to dibenzopyran-6-one derivatives, and the microbial origin of these metabolites has been suggested. However, this has not been demonstrated so far. Fecal samples donated by six volunteers were incubated under anaerobic conditions, and aliquots were used to evaluate the fecal metabolism of ellagic acid, the ellagitannin punicalagin, and an ellagitannin rich extract from walnuts. The isoflavone daidzein was also incubated with the same fecal samples to follow the production of the microbial metabolites previously reported (dihydrogenistein, O-demethylangolensin, and equol) as a positive control of the system and to evaluate similarities between isoflavone and ellagic acid fecal flora metabolism. After fermentation the metabolite “urolithin A” (3,8-dihydroxy-6H-dibenzo[b,d]pyran-6-one) was produced from ellagic acid, punicalagin, and the ellagitannin extract in all the fecal cultures from different volunteers, but with very different production rates and concentrations. This large variability in the concentration of metabolite and kinetics of metabolite production is consistent with the large variability found in the excretion of these metabolites in urine in vivo after human consumption of ellagitannins...

‣ Metabolism of antioxidant and chemopreventive ellagitannins from strawberries, raspberries, walnuts, and oak-aged wine in humans: identification of biomarkers and individual variability

Cerdá, Begoña; Tomás Barberán, Francisco; Espín de Gea, Juan Carlos
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artículo Formato: 21391 bytes; application/pdf
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9 pages, 5 figures, 2 tables.-- PMID: 15656654 [PubMed].-- Available online Dec 29, 2004.; Ellagitannins (ETs) are dietary polyphenols, containing ellagic acid (EA) subunits, with antioxidant and cancer chemopreventive activities that might contribute to health benefits in humans. However, little is known about their metabolic fate. We investigate here the metabolism of different dietary ETs and EA derivatives in humans. Forty healthy volunteers were distributed in four groups. Each group consumed, in a single dose, a different ET-containing foodstuff, i.e., strawberries (250 g), red raspberries (225 g), walnuts (35 g), and oak-aged red wine (300 mL). After the intake, five urine fractions (F) were collected at 8 (F1), 16 (F2), 32 (F3), 40 (F4), and 56 (F5) h. Neither ETs nor EA were detected in urine after LC-MS/MS analysis. However, the microbial metabolite 3,8-dihydroxy-6H-dibenzo[b,d]pyran-6-one (urolithin B) conjugated with glucuronic acid was detected along the fractions F3-F5 in all of the subjects, independently of the consumed foodstuff. The mean percentage of metabolite excretion ranged from 2.8 (strawberries) to 16.6% (walnuts) regarding the ingested ETs. Considerable interindividual differences were noted, identifying "high and low metabolite excreters" in each group...

‣ The potent in vitro antioxidant ellagitannins from pomegranate juice are metabolised into bioavailable but poor antioxidant hydroxy–6H–dibenzopyran–6– one derivatives by the colonic microflora of healthy humans

Cerdá, Begoña; Espín de Gea, Juan Carlos; Parra, S.; Martínez, P.; Tomás Barberán, Francisco
Fonte: Springer Publicador: Springer
Tipo: Artículo Formato: 259768 bytes; application/pdf
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16 pages, 3 tables, 7 figures.-- Online version published Jan 2004.; [Background]: The antiatherogenic activity of pomegranate juice has been attributed to its antioxidant polyphenols. The most potent in vitro antioxidant polyphenol from this juice is the ellagitannin punicalagin. However, the bioavailability of ellagitannins, including punicalagin, has not been previously described in humans.; [Aim of the study]: The present work aims to evaluate, in healthy humans, the bioavailability and metabolism of pomegranate juice ellagitannins, to assess their effect on several blood parameters (including cardiovascular risk disease markers) and to compare the antioxidant activity of punicalagin with that of the in vivo generated metabolites.; [Design]: Six healthy subjects (four men and two women) consumed 1 L of pomegranate juice daily (5.58 g/L polyphenols, including 4.37 g/L punicalagin isomers) for 5 days. The polyphenols and the in vivo generated metabolites were measured by HPLC–DAD–MS–MS. Fourteen haematological and twenty serobiochemical parameters including LDL, HDL and VLDL as well as cholesterol and triglycerides in each lipoprotein were evaluated. In vitro antioxidant activity of plasma (ABTS and FRAP assays) and urine (ABTS and DPPH) were determined.; [Results]: Neither punicalagin nor ellagic acid present in the juice were detected in both plasma and urine. Three microbial ellagitannin-derived metabolites were detected: 3...

‣ Pomegranate juice supplementation in chronic obstructive pulmonary disease: a 5-week randomized, double-blind, placebo-controlled trial

Cerdá, Begoña; Soto, C.; Albaladejo, M. D.; Martínez, P.; Sánchez-Gascón, F.; Tomás Barberán, Francisco; Espín de Gea, Juan Carlos
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artículo Formato: 259768 bytes; application/pdf
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9 pages, 3 tables, 1 figure.-- Published online 9 November 2005.; [Objective]: The aim of the present study is to investigate the effect of antioxidant polyphenol-rich pomegranate juice (PJ) supplementation for 5 weeks on patients with stable chronic obstructive pulmonary disease (COPD), since the oxidative stress plays a major role in the evolution and pathophysiology of COPD.; [Design]: A randomized, double-blind, placebo-controlled trial was conducted.; [Subjects]: A total of 30 patients with stable COPD were randomly distributed in two groups (15 patients each).; [Interventions]: Both groups consumed either 400 ml PJ daily or matched placebo (synthetic orange-flavoured drink) for 5 weeks. Trolox Equivalent Antioxidant Capacity (TEAC) of PJ, blood parameters (14 haematological and 18 serobiochemical), respiratory function variables, bioavailability of PJ polyphenols (plasma and urine) and urinary isoprostane (8-iso-PGF2) were evaluated.; [Results]: The daily dose of PJ (containing 2.66 g polyphenols) provided 4 mmol/l TEAC. None of the polyphenols present in PJ were detected in plasma or in urine of volunteers. The most abundant PJ polyphenols, ellagitannins, were metabolized by the colonic microflora of COPD patients to yield two major metabolites in both plasma and urine (dibenzopyranone derivatives) with no TEAC. No differences were found (P>0.05) between PJ and placebo groups for any of the parameters evaluated (serobiochemical and haematological)...

‣ Colonic drug delivery. I- The colon as a site for drug delivery; Liberação específica de fármacos para administração no cólon por via oral. I - O cólon como local de liberação de fármacos

Freire, Ana Cristina; Podczeck, Fridrun; Sousa, João; Veiga, Francisco
Fonte: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Artigo Avaliado pelos Pares Formato: application/pdf
Publicado em 01/09/2006 Português
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Drug delivery to the colon has become attractive to researchers interested in the treatment of local diseases and for its potential for the delivery of proteins and therapeutic peptides. The treatment of colonic disorders like the inflammatory bowel disease can be improved by the use of systems capable of delivering the appropriate pharmacological agent selectively in the active site of inflammation, because it reduces the oral dose and its systemic side effects. The activity of the peptidases in the colon is very low, which makes possible to such labile molecules like proteins and peptides to be orally administered, without compromising their bioavailability. In the development of these systems it is fundamental to fully understand the colon as a site for drug delivery and, in particular, aspects like transit time, pH and enzyme activity of the colon, which are the basic mechanisms used to trigger release of a drug in the colon. Another important aspect is the absorptive capacity of the colon. In this context, the long residence time and the presence of some biological and chemical barriers might, respectively, enhance or limit drug absorption. The impact of the active inflammatory bowel disease on the efficacy of the systems used for targeting drugs to the colon might have been underestimated...

‣ Colonic drug delivery. II- Types of delivery systems; Liberação específica de fármacos no cólon por via oral. II - Tipos de sistemas utilizados

Freire, Ana Cristina; Podczeck, Fridrun; Sousa, João; Veiga, Francisco
Fonte: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Artigo Avaliado pelos Pares Formato: application/pdf
Publicado em 01/09/2006 Português
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Two basic approaches may be taken in delivering drugs to the colon: time-delayed release or colonic targeting. The former involves sustained release dosage forms, which are designed to prolong drug dissolution and hence absorption, until it reaches the colon. This strategy shows lack of specificity when compared with others that take advantage of unique characteristics present in the colon. Direct targeting involves the exploitation of environmental properties of the colon, like pH of the colon, enzymatic activity or intraluminal pressure. In general, the ideal colonic drug delivery may be accomplished by using pellets, which are known to have more predictable gastric emptying and great colonic residence times, and coated dosage forms with a simple design since they are easy to manufacture. Theoretically, the enzyme dependent systems, and, specially, those based in the use of polysaccharides, are more specific and non-toxic. Nevertheless, any of the others approaches might be suitable to obtain a colonic delivery system with the appropriate characteristics. Some commercially time-dependent and pH-dependent systems have shown important benefits in the treatment of inflammatory bowel disease, despite their less specificity. The investigations in this field should be conducted to identify the appropriate approach...

‣ Treatment of irritable bowel syndrome with probiotics: An etiopathogenic approach at last?

Bixquert Jiménez,M.
Fonte: Revista Española de Enfermedades Digestivas Publicador: Revista Española de Enfermedades Digestivas
Tipo: info:eu-repo/semantics/article; journal article; info:eu-repo/semantics/publishedVersion Formato: text/html; application/pdf
Publicado em 01/08/2009 Português
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Irritable bowel syndrome (IBS) is the most common functional digestive disorder, and may affect 11-20% of the adult population in industrialized countries. In accordance with Rome III criteria (2006) IBS involves abdominal pain and bowel habit disturbance, which are not explained by structural or biochemical abnormalities. Several hypotheses attempt to account for the pathophysiology of IBS, but the etiology still remains uncertain or obscure, perhaps multifactorial. Abnormalities in colonic microflora have recently been suggested in such patients, as has abnormal small-intestine bacterial overgrowth (SIBO), or in particular a significant reduction in the amount of intraluminal Bifidobacteria or Lactobacilli, with consequences like the production of colonic gas, and motility or sensitivity disturbances of the intestinal tract. The disorder is difficult to treat, and the wide spectrum of non-drug and drug treatments shows our ignorance about the cause of the condition. Newer drugs, both pro- and anti-serotonin, have failed to show long-term efficacy or have been withdrawn due to concerns about harmful effects. Recent research has provided increasing support for the idea that disturbances of intestinal microbiota occur in patients with IBS...