Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “INTESTINAL MICROORGANISMS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources
PubMed2002

Adhesion of lactic acid bacteria to caco-2 cells and their effect on cytokine secretion.

Cytokines secreted by human enterocytes play a critical role in mucosal and systemic immunity. Intestinal microorganisms can influence this secretion. In the present study, 30 strains of lactic acid bacteria were characterized for their adhesion to Caco-2 cells and their potential to stimulate proinflammatory cytokine secretion by this cell line. The bacteria adhered in a strain-dependent manner to Caco-2 cells. Contact with lactobacilli did not result in the production of IL-6 or IL-8. A slight IL-6 and IL-8 production by a Caco-2 cell was detected after exposure to 8 of the tested Bifidobacterium strains. No correlation was found between adhesion and cytokine induction among the bacteria tested. This indicates that lactic acid bacteria, even those with strong adhesive properties, are not very likely to trigger an inflammatory response in human enterocytes.

Adult↗
PubMed1997

Binding of 3H-metronidazole in olfactory, respiratory and alimentary epithelia in rats.

Whole-body autoradiography of 3H-metronidazole in rats showed retention of bound metabolites in the epithelia lining the olfactory part of the nose, the tongue, the gingiva, the palate, the pharynx, the oesophagus and the forestomach. In vitro microautoradiography in O2- and N2-atmosphere with some of these tissues indicated reductive formation of bound metabolites in specific cells of the epithelia. Studies with subcellular fractions of the nasal olfactory mucosa showed formation of DNA- and protein-bound metronidazole metabolites. A lower bioactivating capacity was found in experiments with the liver. The bioactivation was dependent on N2-atmosphere, and presence of the P450-inhibitor metyrapone or GSH in the incubation media depressed the protein-binding of metronidazole both in the nasal olfactory mucosa and the liver. These data indicate that the bioactivation is partly P450-dependent and GSH may play an important role in scavaging the bioactivated drug. The epithelial cells with a capacity to bioactivate metronidazole may be potential targets for negative effects of the drug. Whole-body autoradiography also showed a strong binding of radioactivity in the contents of caecum and colon. This can be considered to be due to reductive bioactivation of metronidazole by the intestinal microorganisms and reflects the principal site of action of the drug.

Animals↗
PubMed1981

Microbial conversion of bilirubin to urobilins in vitro and in vivo.

No urobilins are formed from bilirubin in germ-free rats. To isolate and investigate the strains of intestinal microorganisms responsible for this transformation, a suitable test medium was adopted. The strength of the medium and a rather high initial pH were found to be of importance. In this medium, suspensions of rat faeces and a single strain, Cl. ramosum (G62), converted bilirubin to urobilins. Cultivations of Cl. ramosum (G62) together with E. coli significantly enhanced the conversion, whereas addition of 4 other bacterial strains was without the influence. The highest in vitro formation of the urobilins was about 10% of the bilirubin present. When the 6 strains investigated in vitro were established in EXG rats, the in vivo conversion of bilirubin to urobilins was found to be about 15%, compared to 70% in CONV rats.

Animals↗
PubMed1965

INTESTINAL BACTERIAL FLORA AND TRANSIT TIME OF THREE NEOTROPICAL BAT SPECIES.

Klite, P. D. (Middle America Research Unit, Balboa Heights, Canal Zone). Intestinal bacterial flora and transit time of three neotropical bat species. J. Bacteriol. 90:375-379. 1965.-Quantitative studies on the intestinal bacterial flora of three neotropical bat species revealed the following average bacterial populations: Molossus major, 10(4.8) bacteria per intestinal contents; Carollia perspicillata, 10(3.3); Chilonycteris rubiginosa, 10(3.9). In comparison, laboratory mice had an average of 10(9.7) bacteria per intestinal contents. Of 236 bacterial isolates obtained from 60 bats, bacteria of the Klebsiella-Aerobacter-Serratia group were found most frequently, followed by enterococci and Proteus spp. Bacteria of eight other groups were less frequently recovered. A large intestine, cecum, or appendix was absent in all three bat species, and the intestinal length was one-third to one-fifth of that in a mouse of comparable weight. The transit time through the short bat intestine was 15 min. The possible relationship of these unusual anatomical and physiological phenomena to the ability of Histoplasma capsulatum to survive in bat feces is discussed.

Anatomy, Comparative↗
PubMed1963

Bacteriological and histological studies of the small intestine of rats treated with mecamylamine.

Rats were injected intraperitoneally with mecamylamine (Inversine) in doses that were believed to have reduced peristaltic activity in the small intestine. Large numbers of Escherichia coli were present throughout the lumen of the small intestine of animals treated for two or three days and killed within three hours of the last dose of the drug. Histological changes in the small intestinal mucosa of these animals included an increase in the number of goblet cells and shortening and thickening of the villi. Bacteria invaded the intestinal wall of some of the animals. Animals killed 24 hours after the last dose of the drug showed no significant change from the normal controls. The findings support the hypothesis that bacteria are removed mechanically from the normal small intestine by peristalsis. Certain of the histological changes are similar to those seen in the small intestine in malabsorptive conditions in man and the relationship between hypomotility, the bacterial population, and malabsorption is discussed.

Animals↗
PubMed2006

Human milk oligosaccharides inhibit the adhesion to Caco-2 cells of diarrheal pathogens: Escherichia coli, Vibrio cholerae, and Salmonella fyris.

Breast-fed children, compared with the bottle-fed ones, have a lower incidence of acute gastroenteritis due to the presence of several antiinfective factors in human milk. The aim of this work is to study the ability of human milk oligosaccharides to prevent infections related to some common pathogenic bacteria. Oligosaccharides of human milk were fractionated by gel-filtration and characterized by thin-layer chromatography and high-performance anion exchange chromatography. Fractions obtained contained, respectively, 1) acidic oligosaccharides, 2) neutral high-molecular-weight oligosaccharides, and 3) neutral low-molecular-weight oligosaccharides. Experiments were carried out to study the ability of oligosaccharides in inhibiting the adhesion of three intestinal microorganisms (enteropathogenic Escherichia coli serotype O119, Vibrio cholerae, and Salmonella fyris) to differentiated Caco-2 cells. The study showed that the acidic fraction had an antiadhesive effect on the all three pathogenic strains studied (with different degrees of inhibition). The neutral high-molecular-weight fraction significantly inhibited the adhesion of E. coli O119 and V. cholerae, but not that of S. fyris; the neutral low-molecular-weight fraction was effective toward E. coli O119 and S. fyris but not V. cholerae. Our results demonstrate that human milk oligosaccharides inhibit the adhesion to epithelial cells not only of common pathogens like E. coli but also for the first time of other aggressive bacteria as V. cholerae and S. fyris. Consequently, oligosaccharides are one of the important defensive factors contained in human milk against acute diarrheal infections of breast-fed infants.

Animals↗
PubMed1991

Lipid metabolism in anaerobic ecosystems.

In anaerobic ecosystems, acyl lipids are initially hydrolyzed by microbial lipases with the release of free fatty acids. Glycerol, galactose, choline, and other non-fatty acid components released during hydrolysis are fermented to volatile fatty acids by the fermentative bacteria. Fatty acids are not degraded further in the rumen or other parts of the digestive tract but are subjected to extensive biohydrogenation especially in the rumen. However, in environments such as sediments and waste digestors, which have long retention times, both long and short chain fatty acids are beta-oxidized to acetate by a special group of bacteria, the H2-producing syntrophs. Long chain fatty acids can also be degraded by alpha-oxidation. Biotransformation of bile acids, cholesterol, and steroids by intestinal microorganisms is extensive. Many rumen bacteria have specific growth requirements for fatty acids such as n-valeric, iso-valeric, 2-methylbutyric, and iso-butyric acids. Some species have requirements for C13 to C18 straight-chain saturated or monoenoic fatty acids for growth.

Anaerobiosis↗
PubMed1999

Measurement of bile salt hydrolase activity from Lactobacillus acidophilus based on disappearance of conjugated bile salts.

Bile salt hydrolase activity of Lactobacillus acidophilus was measured based on the disappearance of sodium glycocholate and sodium taurocholate from the reaction mixture using HPLC. The amount of sodium glycocholate and sodium taurocholate that disappeared was proportional to the amount of sodium cholate that appeared in the mixture as detected by HPLC. Sodium glycocholate did not precipitate at the enzyme reaction conditions (37 degrees C and pH 5.4) for determining bile salt hydrolase activity. The bile salt hydrolase assay was insensitive to low oxidation-reduction potential when measuring bile salt hydrolase from L. acidophilus, an intestinal microorganism. However, EDTA and freezing temperatures were necessary to maintain stability of the partially purified enzyme during storage.

Amidohydrolases↗
PubMed2025

Effects of Sodium-Glucose Cotransporter-2 Inhibitors on Modulating Protein-Bound Uremic Toxins and Gut Microbiota in Predialysis CKD Patients: Matched Case-Control Study.

KEY POINTS: A reduction of indoxyl sulfate, p-cresyl sulfate, and several short-chain fatty acids was seen in sodium-glucose cotransporter-2 inhibitor-treated CKD patients. Variations in gut microbiota composition are correlated with levels of gut-derived uremic toxins in sodium-glucose cotransporter-2 inhibitor-treated CKD patients. BACKGROUND: The intricate interplay between CKD and intestinal microbiota has gained increasing attention, with gut dysbiosis being implicated in uremic toxin accumulation and CKD progression. Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are now transforming CKD management but pose uncertain effects on shaping gut microbiota. This study aimed to elucidate the effect of SGLT2i on perturbations of gut microbial composition and metabolic responses in patients with CKD. METHODS: Analysis of fecal microbiota and targeted profiling of serum short-chain fatty acids and gut-derived uremic toxins were conducted in a matched case-control study, including 60 patients with CKD (treated: n=30; untreated: n=30) and 30 non-CKD controls. RESULTS: Gut microbial composition differed significantly among the three study groups. Patients with CKD receiving SGLT2i exhibited distinctive taxonomic profiles, such as enrichment of Bacteroides stercoris and Bacteroides coprocola. Surveys of metabolomic profiles revealed a reduction of two uremic solutes, indoxyl sulfate and p-cresyl sulfate (pCS), and several short-chain fatty acids (formic, acetic, propionic, valeric, and 2-methylbutanoic acid) in SGLT2i-treated CKD patients. Co-occurrence analysis demonstrated a set of intestinal microbes that is positively or negatively correlated with the levels of pCS, and the abundance of these pCS-associated intestinal microorganisms was correlated with the levels of indoxyl sulfate and isovaleric acids in the same and opposite direction, respectively. Further functional prediction indicated attenuated pathways related to protein and carbohydrate metabolism. CONCLUSIONS: Treatment with SGLT2i in patients with CKD is associated with distinct gut microbial composition and metabolite profiles, suggesting potential modulation of gut dysbiosis and metabolic pathways. Further studies are warranted to elucidate the clinical implications of these findings in CKD management.

CKD↗
PubMed1999

[Parenteral and enteral nutrition in palliative medicine].

Artificial nutritional support does not alter the natural course in patients with malignant disease. The outcome of these patients is mainly determined by the type and stage of the underlying tumor. Progress of the underlying disease is often paralleled by malnutrition which in turn facilitates complications and may reduce survival and quality of life. Nutritional support can be applied to maintain body weight, immune function and quality of life. Enteral nutrition can be applied with a functioning gastrointestinal tract and has been proven to be superior compared to parenteral nutrition. Maintenance of intestinal mucosal function due to enteral substrate application prevents disruption of intestinal barrier function as well as the overgrowth of intestinal microorganisms. Using a step-by-step approach dietetic counselling in combination with augmented oral caloric intake should be the first measure. The next step to take is nutritional support by enteral tube feeding using formula diets. Parenteral feeding should only be used if other options to support caloric intake have failed.

Enteral Nutrition↗
PubMed1976

The immune response in cirrhotic rats. The induction of tolerance to orally administered protein antigens.

Hepatic cirrhosis reduced the susceptibility of rats to the induction of tolerance by the oral administration of a protein antigen. Rats with portacaval shunt were rendered tolerant as readily as normal rats. The orally induced state of partial tolerance was shown to be dependent on thymus-dependent lymphocytes: B lymphocytes reacted normally to challenge when injected with T lymphocytes from normal rats. Several factors may contribute to the reduced responsiveness of the cirrhotic rats to the tolerance regime. First, the cirrhotic liver was shown to have a reduced capacity to separate immunogen from tolerogen. Second, because of the reduced phagocytic capacity of the liver, increased quantities of lipopolysaccharide, derived from intestinal microorganisms, enter the blood stream. These substances and products of hepatocyte necrosis have adjuvant activity and may therefore contribute to the changed state of responsiveness of rats with cirrhosis.

Administration, Oral↗
PubMed2003

A study of Vitamin K status in children on prolonged antibiotic therapy.

Vitamin K deficiency is known to cause coagulopathy and bleeding in patients on prolonged antibiotic therapy. This study was conducted to evaluate the status of vitamin K deficiency in hospitalized children on prolonged antibiotic therapy and its role in reversing the coagulopathy. A prospective non-randomized study was conducted on children on antibiotic therapy at a tertiary care hospital. Children in the 1 month-1 year age group developed significant coagulopathy as compared to other age groups. Coagulation abnormalities were also seen to be more in children with greater grades of malnutrition, on a more prolonged course of antibiotics and in children who were critically ill in intensive care. Hypoprothrombinemia previously reported to be due to B-lactam antibiotics containing the N-Methyl Thio Tetrazole (NMTT) group also resulted from antibiotics without this side chain. Inhibition of intestinal microorganisms by antibiotics was thought to be a likely explanation of this phenomenon. We suggest Vitamin K prophylaxis in severely ill patients, on extended periods of antibiotics and inadequate diet to prevent morbidity and mortality.

Anti-Bacterial Agents↗
PubMedDate not supplied

[The intraluminal transport of vitamin B12].

Since the existence of vitamin B12 was suggested by Castle in the first few decades of this century, vitamin B12 has been the subject of many studies which have proved the high complexity of its assimilation by the organism. Over the last few years the marked progress in functional digestive exploration methods and the physical and the chemical characteristics of biological molecules have revived the established idea of the vitamin's intraluminal transit. Our recent studies have been concentrated on the bilio-duodenopancreatic stage of the vitamin B12 transport. In nature, vitamin B12 is only exceptionally met in its free form, it is always associated with a binder. Like a ball being passed from one player to another it moves between binders. Alimentary vitamin B12 released from its protein complexes by culinary preparation and gastric secretions, is combined with haptocorrin. In the duodenum the transfer of B12 on intrinsic factor is due to partial degradation of haptocorrin by pancreatic enzymes and intraluminal pH balance. Then combined with intrinsic factor the vitamin can be caught by the ileal receptor. The partial degradation haptocorrin joins vitamin B12 analogs from excreted bile or synthesized by the intestinal microorganisms.

Biological Transport↗