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1

Alteration of sulfate and hydrogen metabolism in the human colon by changing intestinal transit rate.  

UK PubMed Central (United Kingdom)

OBJECTIVES: Changes in intestinal transit rate are also implicated in the etiology of many colonic diseases and strongly influence many metabolic processes in the colon. We set out to investigate whether intestinal transit time could influence the activity of the hydrogen-consuming bacterial flora and sulfate metabolism. METHODS: Normal volunteers underwent four interventions while taking a low-sulfate diet: placebo, sulfate supplements, or sulfate supplements with either senna or loperamide. Stools were cultured and analyzed for sulfate, sulfide, methionine, sulfate reduction rates, methionine reduction rates, acetic acid production rates, methane production rates, short-chain fatty acids, and bile acids. Urine was analyzed for sulfate. RESULTS: The addition of sulfate alone increased fecal and urinary excretion of sulfate, fecal sulfide, sulfate reduction rates, and acetic acid production rates; it reduced fecal methanogenic bacterial concentrations. Faster intestinal transit increased fecal sulfate, sulfide, bile acids, the reduction rates of sulfate, and methionine and the production rates of acetic acid. Reduction in fecal methanogens and methane production was seen. The reverse effects were seen with loperamide. CONCLUSIONS: Both sulfate supplements and changes in intestinal transit rate markedly alter the activity of the colonic bacterial flora with respect to sulfate metabolism and hydrogen disposal. Dietary influences on intestinal transit and sulfate consumption may influence disease processes. While a variety of processes govern sulfate metabolism and hydrogen disposal, our knowledge is far from complete. How far the observed changes in sulfate metabolism seen in certain diseases are relevant to the pathogenesis of the disease or secondary to the disease itself is unclear.

Lewis S; Cochrane S

2007-03-01

2

Relationship between postprandial motor activity in the human small intestine and the gastrointestinal transit of food  

Energy Technology Data Exchange (ETDEWEB)

Profiles for gastric emptying and colonic filling were determined in 20 normal volunteers by means of a gamma camera and dedicated minicomputer after ingestion of a radiolabeled solid meal. These were compared with intraluminal pressure activity, recorded simultaneously from three sites (each separated by 50 cm) in the small intestine by infusion manometry. Recordings were continued for at least 8 h or until all the radioactivity appeared in the colon. Colonic filling was approximately linear, occurring at an average rate of 16% of the meal residues per hour. There were significant inverse correlations (p less than 0.01) between the pressure activity in the proximal jejunum during the first 3 h after ingestion and the times taken for 50% and 80% of the meal residues to enter the colon, and direct correlations between total small intestinal pressure activity and the half-time for gastric emptying. Phase III of the interdigestive migrating motor complex appeared between 3 and 9 h after ingestion (when between 15% and 80% of the meal remained in the small intestine), but did not necessarily migrate to the next recording site until much later. The time of appearance of phase III in the proximal jejunum was directly correlated with the half-time for gastric emptying (p less than 0.05) and with the intraluminal pressure activity recorded at that site during the first 3 h after food ingestion (p less than 0.01). The time at which 80% of the meal residues had entered the colon was significantly shorter in 6 subjects, in whom a postprandial activity front appeared to migrate throughout the small bowel, compared with 13 subjects, in whom this did not occur (5.0 +/- 0.5 h vs. 7.0 +/- 0.4 h, p less than 0.01). These studies have shown that gastrointestinal transit of a solid meal is related to both fed and fasted intraluminal pressure activity in the small intestine.

Read, N.W.; Al-Janabi, M.N.; Edwards, C.A.; Barber, D.C.

1984-04-01

3

Intestinal microbiota and human diseases  

Directory of Open Access Journals (Sweden)

Full Text Available The majority of human intestinal microbiota are harmless or even beneficial by performing functions essential for our survival. Changes in the microbial species that reside in our intestines have been associated with a long list of illness. The review provided an overview of the association between the microbiota and the occurrence of human diseases, and to stimulate future researches regarding infectious diseases and their consequences.

Zi-kai WANG; Yun-sheng YANG

2012-01-01

4

Human intestinal spirochetosis – a review  

Directory of Open Access Journals (Sweden)

Full Text Available Human intestinal spirochetosis (IS) is a condition defined histologically by the presence of spirochetal microorganisms attached to the apical cell membrane of the colorectal epithelium. Intestinal spirochetes comprise a heterogeneous group of bacteria. In humans, Brachyspira aalborgi and Brachyspira pilosicoli predominate. Prevalence rates of IS are low where living standards are high, in contrast to poorly developed areas where IS is common. Homosexuals and HIV-infected individuals are at high risk of being colonized. Clinical significance in individual cases has remained unclear up to now. A review of the literature assumes that invasion of spirochetes beyond the surface epithelium may be associated with gastrointestinal symptoms which respond to antibiotic treatment (metronidazole), whereas individuals lacking this feature may be mostly asymptomatic. Of unknown reason, homosexual and HIV-positive men as well as children are more likely to be symptomatic irrespective of invasion. Rare cases of spirochetemia and multiple organ failure have been reported in critically ill patients with IS.

Tsinganou, Efstathia; Gebbers, Jan-Olaf

2010-01-01

5

Radioimmunoassay of human intestinal alkaline phosphatase  

International Nuclear Information System (INIS)

A new method of radioimmunoassay using the double antibody method for human intestinal alkaline phosphatase (ALP) was first elaborated. The following results were obtained: 1) In this system, the optimal antibody concentration is 10,000 times the dilution of the original anti-serum, and the optimal assay range is 0.5 to 25 ng. Enzymatic activity of 1 ng intestinal ALP is 4.1 King-Armstrong units. 2) In this system, the sera including intestinal ALP are divided to two groups. One group shows a dose response curve similar to that of purified intestinal ALP, and the other shows a lesser one. This reason is not clear. Hepatic ALP, osseous ALP and placental ALP in the sera show no response in this system. 3) In this system, the B/T value of 50 ?g of purified human placental ALP is almost equal to 1 ng of purified human intestinal ALP. Similarly, the B/T value of 50 ?g of purified human intestinal ALP is equal to almost 5 ng of purified human placental ALP. This shows that cross-reaction exists between intestinal and placental ALPs at high concentrations. (J.P.N.)

1976-01-01

6

Effects of methotrexate on intestinal transit in rats  

International Nuclear Information System (INIS)

A study was designed to determine the effects of methotrexate (MTX) on rat intestinal transit. Adult male rats were implanted with indwelling cannulas in the proximal duodenum 5 to 7 days prior to experimentation. After recovery from surgery, groups of animals were treated with either saline (1.0 ml/kg/day) or MTX at 0.5, 1.25, 3.125, or 7.8 mg/kg/day (ip) for 3 consecutive days (Days 1-3). On each of the next 5 consecutive days (Days 4-8) weight and intestinal transit determinations were made in animals from each test group following a 24-hr fast. Intestinal transit was determined by measuring the progression of an intraduodenally administered bolus of radioactive chromium (Na251CrO4, 0.5 mu Ci) through the small intestine. When compared with saline-treated controls, intestinal transit was significantly (p less than 0.05) increased on 1 or more of the 5 test days in animals treated with doses of MTX greater than 0.5 mg/kg/day. When compared with animals treated with saline, animals treated with MTX lost a greater percentage of their initial body weight after the fast period. Plasma concentrations of MTX, determined at various time intervals after 3.125 mg/kg given daily for 1 to 3 consecutive days, peaked at 15 and 30 min after each injection and diminished to undetectable levels after 4 hr. The results indicate that 3 days of parenteral therapy with MTX significantly increases rat intestinal transit. The intestinal effects appear to be transient and are proportional to the total dose of drug administered over the 3-day period. The intestinal effects of MTX occur from 1 to several days after peak plasma concentrations of drug and are associated with a reduced ability to sustain body weight after a 24-hr fast

1985-01-01

7

Effects of methotrexate on intestinal transit in rats  

Energy Technology Data Exchange (ETDEWEB)

A study was designed to determine the effects of methotrexate (MTX) on rat intestinal transit. Adult male rats were implanted with indwelling cannulas in the proximal duodenum 5 to 7 days prior to experimentation. After recovery from surgery, groups of animals were treated with either saline (1.0 ml/kg/day) or MTX at 0.5, 1.25, 3.125, or 7.8 mg/kg/day (ip) for 3 consecutive days (Days 1-3). On each of the next 5 consecutive days (Days 4-8) weight and intestinal transit determinations were made in animals from each test group following a 24-hr fast. Intestinal transit was determined by measuring the progression of an intraduodenally administered bolus of radioactive chromium (Na/sub 2//sup 51/CrO/sub 4/, 0.5 mu Ci) through the small intestine. When compared with saline-treated controls, intestinal transit was significantly (p less than 0.05) increased on 1 or more of the 5 test days in animals treated with doses of MTX greater than 0.5 mg/kg/day. When compared with animals treated with saline, animals treated with MTX lost a greater percentage of their initial body weight after the fast period. Plasma concentrations of MTX, determined at various time intervals after 3.125 mg/kg given daily for 1 to 3 consecutive days, peaked at 15 and 30 min after each injection and diminished to undetectable levels after 4 hr. The results indicate that 3 days of parenteral therapy with MTX significantly increases rat intestinal transit. The intestinal effects appear to be transient and are proportional to the total dose of drug administered over the 3-day period. The intestinal effects of MTX occur from 1 to several days after peak plasma concentrations of drug and are associated with a reduced ability to sustain body weight after a 24-hr fast.

Curd, C.D.; Manno, J.E.; Stewart, J.J.

1985-10-01

8

A comparative evaluation of intestinal transit time of two dosage forms of Haritaki [Terminalia chebula Retz].  

Science.gov (United States)

Haritaki is praised as the best salutary drug which can be used in almost all ages of human life and is reputed for its Anulomana property. In Ayurveda, it has been mentioned that fruits of Haritaki when used in different forms give different type of actions. As the prime therapeutic utility of Haritaki is Anulomana, in the present study, two dosage forms of Haritaki fruits namely Churna and Vati were evaluated for intestinal transit time to evaluate its effect in two different dosage forms. Mature fruits were collected, authenticated, and processed as per classics to get Churna and Vati. Test drugs were administered in the dose of 550 mg/kg and evaluation on intestinal transit time was carried out by adopting kaolin expulsion test in mice. The results show that both the dosage forms of Haritaki significantly shortened intestinal transit time and between them Churna form is found to be better. PMID:23723658

Jirankalgikar, Yogesh M; Ashok, B K; Dwivedi, Rambabu R

2012-07-01

9

A comparative evaluation of intestinal transit time of two dosage forms of Haritaki [Terminalia chebula Retz].  

UK PubMed Central (United Kingdom)

Haritaki is praised as the best salutary drug which can be used in almost all ages of human life and is reputed for its Anulomana property. In Ayurveda, it has been mentioned that fruits of Haritaki when used in different forms give different type of actions. As the prime therapeutic utility of Haritaki is Anulomana, in the present study, two dosage forms of Haritaki fruits namely Churna and Vati were evaluated for intestinal transit time to evaluate its effect in two different dosage forms. Mature fruits were collected, authenticated, and processed as per classics to get Churna and Vati. Test drugs were administered in the dose of 550 mg/kg and evaluation on intestinal transit time was carried out by adopting kaolin expulsion test in mice. The results show that both the dosage forms of Haritaki significantly shortened intestinal transit time and between them Churna form is found to be better.

Jirankalgikar YM; Ashok BK; Dwivedi RR

2012-07-01

10

Human intestinal capillariasis in Thailand  

Directory of Open Access Journals (Sweden)

Full Text Available Intestinal capillariasis caused by Capillaria philippinensis appeared first in the Philippines and subsequently in Thailand, Japan, Iran, Egypt and Taiwan; major outbreaks have occurred in the Philippines and Thailand. This article reviews the epidemiology, history and sources of C. philippinensis infection in Thailand. The annual epidemiological surveillance reports indicated that 82 accumulated cases of intestinal capillariasis were found in Thailand from 1994-2006. That made Thailand a Capillaria-prevalent area. Sisaket, in northeast Thailand, was the first province which has reported intestinal capillariasis. Moreover, Buri Ram presented a high prevalence of intestinal capillariasis, totaling 24 cases from 1994-2006. About half of all cases have consumed raw or undercooked fish. However, even if the numbers of the intestinal capillariasis cases in Thailand is reduced, C. philippinensis infection cases are still reported. The improvement of personal hygiene, specifically avoiding consumption of undercooked fish and promoting a health education campaign are required. These strategies may minimize or eliminate C. philippinensis infection in Thailand.

Prasert Saichua, Choosak Nithikathkul, Natthawut Kaewpitoon

2008-01-01

11

Gastric transit and small intestinal transit time and motility assessed by a magnet tracking system  

DEFF Research Database (Denmark)

ABSTRACT: BACKGROUND: Tracking an ingested magnet by the Magnet Tracking System MTS-1 (Motilis, Lausanne, Switzerland) is an easy and minimally-invasive method to assess gastrointestinal transit. The aim was to test the validity of MTS-1 for assessment of gastric transit time and small intestinal transit time, and to illustrate transit patterns detected by the system. Methods: A small magnet was ingested and tracked by an external matrix of 16 magnetic field sensors (4x4) giving a position defined by 5 coordinates (position: x, y, z, and angle: theta, phi). Eight healthy subjects were each investigated three times: (1) with a small magnet mounted on a capsule endoscope (PillCam); (2) with the magnet alone and the small intestine in the fasting state; and (3) with the magnet alone and the small intestine in the postprandial state. Results: Experiment (1) showed good agreement and no systematic differences between MTS-1 and capsule endoscopy when assessing gastric transit (median difference 1 min; range: 0-6 min) and small intestinal transit time (median difference 0.5 min; range: 0-52 min). Comparing experiments (1) and (2) there were no systematic differences in gastric transit or small intestinal transit when using the magnet-PillCam unit and the much smaller magnetic pill. In experiments (2) and (3), short bursts of very fast movements lasting less than 5% of the time accounted for more than half the distance covered during the first two hours in the small intestine, irrespective of whether the small intestine was in the fasting or postprandial state. The mean contraction frequency in the small intestine was significantly lower in the fasting state than in the postprandial state (9.90 min-1 vs. 10.53 min-1) (p=0.03). Conclusion: MTS-1 is reliable for determination of gastric transit and small intestinal transit time. It is possible to distinguish between the mean contraction frequency of small intestine in the fasting state and in the postprandial state.

Worsoe, Jonas; Fynne, Lotte

2011-01-01

12

Faecalibacterium prausnitzii and human intestinal health.  

UK PubMed Central (United Kingdom)

Faecalibacterium prausnitzii is the most abundant bacterium in the human intestinal microbiota of healthy adults, representing more than 5% of the total bacterial population. Over the past five years, an increasing number of studies have clearly described the importance of this highly metabolically active commensal bacterium as a component of the healthy human microbiota. Changes in the abundance of F. prausnitzii have been linked to dysbiosis in several human disorders. Administration of F. prausnitzii strain A2-165 and its culture supernatant have been shown to protect against 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis in mice. Here, we discuss the role of F. prausnitzii in balancing immunity in the intestine and the mechanisms involved.

Miquel S; Martín R; Rossi O; Bermúdez-Humarán L; Chatel J; Sokol H; Thomas M; Wells J; Langella P

2013-06-01

13

Cholesterol esterase activity of human intestinal mucosa  

Energy Technology Data Exchange (ETDEWEB)

It has been suggested that cholesterol absorption in humans is dependent on bile acid pool composition and that expansion of the cholic acid pool size is followed by an increase of the absorption values. Similar observations were reported in rats. In the present study, therefore, the authors investigated some general properties of human intestinal cholesterol esterase, with particular emphasis on the effect of bile acids on this enzymatic activity. Twenty-nine segments of small intestine were taken during operations; the enzymatic activity was studied by using mucosal homogenate as a source of enzyme and oleic acid, cholesterol, and UC-labeled cholesterol as substrates. The time-activity relationship was linear within the first two hours; optimal pH for esterification ranged between 5 and 6.2. There was little difference between the esterifying activity of the jejunal and ileal mucosa. Esterification of cholesterol was observed with all the investigated fatty acids but was maximal with oleic acid. Bile acids did not affect cholesterol esterase activity when present in the incubation mixture at 0.1 and 1.0 mM; the enzymatic activity, however, was significantly inhibited when bile acids were added at 20 mM. In conclusion, this study has shown that the human intestinal mucosa possesses a cholesterol esterase activity; at variance with the rat, however, the human enzyme does not seem to be stimulated by trihydroxy bile acids.

Ponz de Leon, M.; Carubbi, F.; Di Donato, P.; Carulli, N.

1985-11-01

14

Human intestinal spirochetosis--a review.  

Science.gov (United States)

Human intestinal spirochetosis (IS) is a condition defined histologically by the presence of spirochetal microorganisms attached to the apical cell membrane of the colorectal epithelium. Intestinal spirochetes comprise a heterogeneous group of bacteria. In humans, Brachyspira aalborgi and Brachyspira pilosicoli predominate. Prevalence rates of IS are low where living standards are high, in contrast to poorly developed areas where IS is common. Homosexuals and HIV-infected individuals are at high risk of being colonized. Clinical significance in individual cases has remained unclear up to now. A review of the literature assumes that invasion of spirochetes beyond the surface epithelium may be associated with gastrointestinal symptoms which respond to antibiotic treatment (metronidazole), whereas individuals lacking this feature may be mostly asymptomatic. Of unknown reason, homosexual and HIV-positive men as well as children are more likely to be symptomatic irrespective of invasion. Rare cases of spirochetemia and multiple organ failure have been reported in critically ill patients with IS. PMID:20200654

Tsinganou, Efstathia; Gebbers, Jan-Olaf

2010-01-07

15

Human intestinal spirochetosis--a review.  

UK PubMed Central (United Kingdom)

Human intestinal spirochetosis (IS) is a condition defined histologically by the presence of spirochetal microorganisms attached to the apical cell membrane of the colorectal epithelium. Intestinal spirochetes comprise a heterogeneous group of bacteria. In humans, Brachyspira aalborgi and Brachyspira pilosicoli predominate. Prevalence rates of IS are low where living standards are high, in contrast to poorly developed areas where IS is common. Homosexuals and HIV-infected individuals are at high risk of being colonized. Clinical significance in individual cases has remained unclear up to now. A review of the literature assumes that invasion of spirochetes beyond the surface epithelium may be associated with gastrointestinal symptoms which respond to antibiotic treatment (metronidazole), whereas individuals lacking this feature may be mostly asymptomatic. Of unknown reason, homosexual and HIV-positive men as well as children are more likely to be symptomatic irrespective of invasion. Rare cases of spirochetemia and multiple organ failure have been reported in critically ill patients with IS.

Tsinganou E; Gebbers JO

2010-01-01

16

Intestinal transit and systemic metabolism of apple polyphenols.  

UK PubMed Central (United Kingdom)

BACKGROUND: Apples are the most widely consumed fruits in Germany and various other countries. Positive health effects of apple-derived polyphenols in vivo depend on their absorption, metabolism, distribution, and elimination from the body after consumption. Data on the metabolism of these polyphenols in humans are scarce. In order to study the intestinal transit and metabolism of apple polyphenols in humans, a variety of experiments were carried out. METHODS: Polyphenols were incubated with saliva (for 5 min), simulated gastric or duodenal juice (4 or 10 h, respectively), or rat hepatocytes (4 h) under aerobic conditions, and with ileostomy fluid under aerobic conditions for 10 h. The polyphenol profile in human serum (8 h later) and renal elimination in urine (24 h later) were also investigated after consumption of 1 L apple juice. Polyphenols and their metabolites were identified and quantified by high-performance liquid chromatography with diode array detection (HPLC-DAD), HPLC-electrospray ionization-tandem mass spectrometry (ESI-MS/MS), and gas chromatography (GC)-MS. RESULTS: In the presence of native saliva or ileostomy fluid, ?-glycosides of phloretin and quercetin were hydrolyzed, to varying degrees depending on the sugar moiety, and to much lesser degrees in the presence of antibiotics. In the gastric milieu, almost complete degradation of procyanidin B(2) to (-)-epicatechin was observed. In the presence of artificial duodenal juice flavan-3-ol epimerization occurred. Quercetin was completely converted to phloroglucinol, 3,4-dihydroxybenzoic acid, and 2,4,6-trihydroxybenzoic acid. Formation of isomeric products of hydroxycinnamic acid esters and their corresponding methyl esters was also observed, and similar results were obtained after incubation with rat hepatocytes. Products of phase II metabolism, two phloretin O-glucuronides and eight (methyl) quercetin O-glucuronides, were identified in the hepatocyte samples. Following enzymatic hydrolysis, 5-caffeoylquinic acid, 4-p-coumaroylquinic acid, caffeic acid, (-)-epicatechin, phloretin, and quercetin were recovered in both serum and urine (5.3% and 3.5% of the amounts consumed, respectively). In addition, 19.5% of the polyphenols consumed were identified in the urine in the form of hydroxylated phenolic and hippuric acids. CONCLUSION: The findings relating to the absorption, metabolism, and systemic availability of polyphenols in vivo should contribute to our understanding of their biological effects, and the characterization of newly formed metabolites should facilitate further studies.

Kahle K; Kempf M; Schreier P; Scheppach W; Schrenk D; Kautenburger T; Hecker D; Huemmer W; Ackermann M; Richling E

2011-10-01

17

[The intestinal microbiota and human disease].  

Science.gov (United States)

Advances in sequencing technology and the development of metagenomics have opened up new ways to investigate the microorganisms inhabiting the human gut. The intestinal microbiota confer protection against pathogens, contribute to the maturation of the immune system, and regulate host metabolism. The composition of gut microbiota in early life is influenced by mode of birth, diet, and antibiotics. Decreased biodiversity and alterations in the composition of the intestinal microbiota have been observed in many diseases including obesity, neonatal necrotizing enterocolitis, inflammatory bowel disease, and recurrent Clostridium difficile infection. Therapeutic options for the diseases linked to imbalance in the microbiota include modifying the gut microbiota through diet, probiotics, and fecal transplants. (Korean J Gastroenterol 2013;62:85-91). PMID:23981941

Ko, Jae Sung

2013-08-25

18

[The intestinal microbiota and human disease].  

UK PubMed Central (United Kingdom)

Advances in sequencing technology and the development of metagenomics have opened up new ways to investigate the microorganisms inhabiting the human gut. The intestinal microbiota confer protection against pathogens, contribute to the maturation of the immune system, and regulate host metabolism. The composition of gut microbiota in early life is influenced by mode of birth, diet, and antibiotics. Decreased biodiversity and alterations in the composition of the intestinal microbiota have been observed in many diseases including obesity, neonatal necrotizing enterocolitis, inflammatory bowel disease, and recurrent Clostridium difficile infection. Therapeutic options for the diseases linked to imbalance in the microbiota include modifying the gut microbiota through diet, probiotics, and fecal transplants. (Korean J Gastroenterol 2013;62:85-91).

Ko JS

2013-08-01

19

Alternative functional in vitro models of human intestinal epithelia.  

Science.gov (United States)

Physiologically relevant sources of absorptive intestinal epithelial cells are crucial for human drug transport studies. Human adenocarcinoma-derived intestinal cell lines, such as Caco-2, offer conveniences of easy culture maintenance and scalability, but do not fully recapitulate in vivo intestinal phenotypes. Additional sources of renewable physiologically relevant human intestinal cells would provide a much needed tool for drug discovery and intestinal physiology. We compared two alternative sources of human intestinal cells, commercially available primary human intestinal epithelial cells (hInEpCs) and induced pluripotent stem cell (iPSC)-derived intestinal cells to Caco-2, for use in in vitro transwell monolayer intestinal transport assays. To achieve this for iPSC-derived cells, intestinal organogenesis was adapted to transwell differentiation. Intestinal cells were assessed by marker expression through immunocytochemical and mRNA expression analyses, monolayer integrity through Transepithelial Electrical Resistance (TEER) measurements and molecule permeability, and functionality by taking advantage the well-characterized intestinal transport mechanisms. In most cases, marker expression for primary hInEpCs and iPSC-derived cells appeared to be as good as or better than Caco-2. Furthermore, transwell monolayers exhibited high TEER with low permeability. Primary hInEpCs showed molecule efflux indicative of P-glycoprotein (Pgp) transport. Primary hInEpCs and iPSC-derived cells also showed neonatal Fc receptor-dependent binding of immunoglobulin G variants. Primary hInEpCs and iPSC-derived intestinal cells exhibit expected marker expression and demonstrate basic functional monolayer formation, similar to or better than Caco-2. These cells could offer an alternative source of human intestinal cells for understanding normal intestinal epithelial physiology and drug transport. PMID:23847534

Kauffman, Amanda L; Gyurdieva, Alexandra V; Mabus, John R; Ferguson, Chrissa; Yan, Zhengyin; Hornby, Pamela J

2013-07-08

20

Alternative functional in vitro models of human intestinal epithelia.  

UK PubMed Central (United Kingdom)

Physiologically relevant sources of absorptive intestinal epithelial cells are crucial for human drug transport studies. Human adenocarcinoma-derived intestinal cell lines, such as Caco-2, offer conveniences of easy culture maintenance and scalability, but do not fully recapitulate in vivo intestinal phenotypes. Additional sources of renewable physiologically relevant human intestinal cells would provide a much needed tool for drug discovery and intestinal physiology. We compared two alternative sources of human intestinal cells, commercially available primary human intestinal epithelial cells (hInEpCs) and induced pluripotent stem cell (iPSC)-derived intestinal cells to Caco-2, for use in in vitro transwell monolayer intestinal transport assays. To achieve this for iPSC-derived cells, intestinal organogenesis was adapted to transwell differentiation. Intestinal cells were assessed by marker expression through immunocytochemical and mRNA expression analyses, monolayer integrity through Transepithelial Electrical Resistance (TEER) measurements and molecule permeability, and functionality by taking advantage the well-characterized intestinal transport mechanisms. In most cases, marker expression for primary hInEpCs and iPSC-derived cells appeared to be as good as or better than Caco-2. Furthermore, transwell monolayers exhibited high TEER with low permeability. Primary hInEpCs showed molecule efflux indicative of P-glycoprotein (Pgp) transport. Primary hInEpCs and iPSC-derived cells also showed neonatal Fc receptor-dependent binding of immunoglobulin G variants. Primary hInEpCs and iPSC-derived intestinal cells exhibit expected marker expression and demonstrate basic functional monolayer formation, similar to or better than Caco-2. These cells could offer an alternative source of human intestinal cells for understanding normal intestinal epithelial physiology and drug transport.

Kauffman AL; Gyurdieva AV; Mabus JR; Ferguson C; Yan Z; Hornby PJ

2013-01-01

 
 
 
 
21

Effect of telavancin on human intestinal microflora.  

UK PubMed Central (United Kingdom)

Telavancin is a new lipoglycopeptide antibiotic for the treatment of Gram-positive infections. It has a dual mechanism of action by inhibiting bacterial cell wall synthesis and disrupting the bacterial plasma membrane. The purpose of the present study was to investigate the effect of administration of telavancin on the human intestinal microflora. Thirteen healthy subjects (six males and seven females; age range 18-40 years) received 10mg/kg body weight telavancin by intravenous infusion over a 60-min period once every 24h for 7 days. Plasma and urine were collected on Days 5, 6 and 7 for pharmacokinetic analysis of telavancin. Faecal samples were collected on Days -1 (pre-dose), 2, 5, 7, 9, 14 and 21. Faecal specimens were cultured on non-selective and selective media. Different colony types were counted, isolated in pure culture and identified to genus level. No measurable concentrations of telavancin were found in faeces. No significant effects on the number of Enterobacteriaceae, enterococci, Candida albicans, bifidobacteria, lactobacilli, clostridia and Bacteroides spp. were observed during the study period. No Clostridium difficile strains or toxins were found. No new colonising aerobic and anaerobic Gram-positive bacteria with telavancin minimum inhibitory concentrations of ? 2 mg/L were found. Based on the microbiological data, telavancin has no significant ecological impact on the human intestinal microflora.

Rashid MU; Weintraub A; Nord CE

2011-12-01

22

Effect of telavancin on human intestinal microflora.  

Science.gov (United States)

Telavancin is a new lipoglycopeptide antibiotic for the treatment of Gram-positive infections. It has a dual mechanism of action by inhibiting bacterial cell wall synthesis and disrupting the bacterial plasma membrane. The purpose of the present study was to investigate the effect of administration of telavancin on the human intestinal microflora. Thirteen healthy subjects (six males and seven females; age range 18-40 years) received 10mg/kg body weight telavancin by intravenous infusion over a 60-min period once every 24h for 7 days. Plasma and urine were collected on Days 5, 6 and 7 for pharmacokinetic analysis of telavancin. Faecal samples were collected on Days -1 (pre-dose), 2, 5, 7, 9, 14 and 21. Faecal specimens were cultured on non-selective and selective media. Different colony types were counted, isolated in pure culture and identified to genus level. No measurable concentrations of telavancin were found in faeces. No significant effects on the number of Enterobacteriaceae, enterococci, Candida albicans, bifidobacteria, lactobacilli, clostridia and Bacteroides spp. were observed during the study period. No Clostridium difficile strains or toxins were found. No new colonising aerobic and anaerobic Gram-positive bacteria with telavancin minimum inhibitory concentrations of ? 2 mg/L were found. Based on the microbiological data, telavancin has no significant ecological impact on the human intestinal microflora. PMID:21982049

Rashid, Mamun-Ur; Weintraub, Andrej; Nord, Carl Erik

2011-10-06

23

Human milk oligosaccharides: the novel modulator of intestinal microbiota  

Directory of Open Access Journals (Sweden)

Full Text Available Human milk, which nourishes the early infants, is a source ofbioactive components for the infant growth, development andcommensal formulation as well. Human milk oligosaccharide is agroup of complex and diverse glycans that is apparently notabsorbed in human gastrointestinal tract. Although mostmammalian milk contains oligosaccharides, oligosaccharides inhuman milk exhibit unique features in terms of their types,amounts, sizes, and functionalities. In addition to the preventionof infectious bacteria and the development of early immunesystem, human milk oligosaccharides are able to facilitate thehealthy intestinal microbiota. Bifidobacterial intestinal microbiotaappears to be established by the unilateral interaction betweenmilk oligosaccharides, human intestinal activity and commensals.Digestibility, membrane transportation and catabolic activity bybacteria and intestinal epithelial cells, all of which are linked tothe structural of human milk oligosaccharides, are crucial indetermining intestinal microbiota.

Kyunghun Jeong1, Vi Nguyen2 & Jaehan Kim1,*

2012-01-01

24

Acquired macrolide resistance in the human intestinal strain Lactobacillus rhamnosus E41 associated with a transition mutation in 23S rRNA genes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Final full-text version of the paper available at: http://dx.doi.org/10.1016/j.ijantimicag.2007.06.002. , Restriction fragment length polymorphism and DNA sequencing of polymerase chain reaction (PCR) products showed that a Lactobacillus rhamnosus strain of human origin resistant to macrolides, from wh...

Flórez García, Ana Belén; Ladero Losada, Victor Manuel; Álvarez Martín, Pablo; Ammor, Mohammed Salim; Álvarez González, Miguel Ángel

25

Generating human intestinal tissue from pluripotent stem cells in vitro.  

UK PubMed Central (United Kingdom)

Here we describe a protocol for generating 3D human intestinal tissues (called organoids) in vitro from human pluripotent stem cells (hPSCs). To generate intestinal organoids, pluripotent stem cells are first differentiated into FOXA2(+)SOX17(+) endoderm by treating the cells with activin A for 3 d. After endoderm induction, the pluripotent stem cells are patterned into CDX2(+) mid- and hindgut tissue using FGF4 and WNT3a. During this patterning step, 3D mid- or hindgut spheroids bud from the monolayer epithelium attached to the tissue culture dish. The 3D spheroids are further cultured in Matrigel along with prointestinal growth factors, and they proliferate and expand over 1-3 months to give rise to intestinal tissue, complete with intestinal mesenchyme and epithelium comprising all of the major intestinal cell types. To date, this is the only method for efficiently directing the differentiation of hPSCs into 3D human intestinal tissue in vitro.

McCracken KW; Howell JC; Wells JM; Spence JR

2011-12-01

26

Combinatorial QSAR modeling of human intestinal absorption.  

UK PubMed Central (United Kingdom)

Intestinal drug absorption in humans is a central topic in drug discovery. In this study, we use a broad selection of machine learning and statistical methods for the classification and numerical prediction of this key end point. Our data set is based on a selection of 458 small druglike compounds with FDA approval. Using easily available tools, we calculated one- to three-dimensional physicochemical descriptors and used various methods of feature selection (best-first backward selection, correlation analysis, and decision tree analysis). We then used decision tree induction (DTI), fragment-based lazy-learning (LAZAR), support vector machine classification, multilayer perceptrons, random forests, k-nearest neighbor and Naïve Bayes analysis to model absorption ratios and binary classification (well-absorbed and poorly absorbed compounds). Best performance for classification was seen with DTI using the chi-squared analysis interaction detector (CHAID) algorithm, yielding corrected classification rate of 88% (Matthews correlation coefficient of 75%). In numeric predictions, the multilayer perceptron performed best, achieving a root mean squared error of 25.823 and a coefficient of determination of 0.6. In line with current understanding is the importance of descriptors such as lipophilic partition coefficients (log P) and hydrogen bonding. However, we are able to highlight the utility of gravitational indices and moments of inertia, reflecting the role of structural symmetry in oral absorption. Our models are based on a diverse data set of marketed drugs representing a broad chemical space. These models therefore contribute substantially to the molecular understanding of human intestinal drug absorption and qualify for a generalized use in drug discovery and lead optimization.

Suenderhauf C; Hammann F; Maunz A; Helma C; Huwyler J

2011-02-01

27

Combinatorial QSAR modeling of human intestinal absorption.  

Science.gov (United States)

Intestinal drug absorption in humans is a central topic in drug discovery. In this study, we use a broad selection of machine learning and statistical methods for the classification and numerical prediction of this key end point. Our data set is based on a selection of 458 small druglike compounds with FDA approval. Using easily available tools, we calculated one- to three-dimensional physicochemical descriptors and used various methods of feature selection (best-first backward selection, correlation analysis, and decision tree analysis). We then used decision tree induction (DTI), fragment-based lazy-learning (LAZAR), support vector machine classification, multilayer perceptrons, random forests, k-nearest neighbor and Naïve Bayes analysis to model absorption ratios and binary classification (well-absorbed and poorly absorbed compounds). Best performance for classification was seen with DTI using the chi-squared analysis interaction detector (CHAID) algorithm, yielding corrected classification rate of 88% (Matthews correlation coefficient of 75%). In numeric predictions, the multilayer perceptron performed best, achieving a root mean squared error of 25.823 and a coefficient of determination of 0.6. In line with current understanding is the importance of descriptors such as lipophilic partition coefficients (log P) and hydrogen bonding. However, we are able to highlight the utility of gravitational indices and moments of inertia, reflecting the role of structural symmetry in oral absorption. Our models are based on a diverse data set of marketed drugs representing a broad chemical space. These models therefore contribute substantially to the molecular understanding of human intestinal drug absorption and qualify for a generalized use in drug discovery and lead optimization. PMID:21142073

Suenderhauf, Claudia; Hammann, Felix; Maunz, Andreas; Helma, Christoph; Huwyler, Jörg

2010-12-29

28

Cholinergic mediation of small intestinal transit in the rat  

International Nuclear Information System (INIS)

It has been reported that small intestinal transit (SIT) in the rat is not cholinergically mediated. The geometric mean of a marker may be a more powerful method for SIT studies. Therefore, it was their goal to evaluate the effect of muscarinic blockade in normal and prostaglandin E2 (PGE2)-enhanced SIT using this method. Male, food-fasted rats (190 to 240 g) were first dosed subcutaneously with atropine. 30 min after the atropine the rats received an oral dose of PGE2 at 5.0 mg/kg. 5 min after PGE2, a 51Cr-labeled marker was dosed intraduodenally, and a 25 min transit period followed. The results are: (1) 5.0 mg/kg of PGE2 significantly stimulates the geometric mean of the marker in agreement with previous findings and (2) atropine is inhibitory at doses as low as 0.20 mg/kg for basal SIT and 0.10 mg/kg for PGE2-stimulated SIT. This indicates (1) the rat has cholinergically mediated SIT, and (2) cholinergic activation may be important for PGE2 effects on SIT in the rat

1986-03-05

29

A Revised Model for Dosimetry in the Human Small Intestine  

International Nuclear Information System (INIS)

A new model for an adult human gastrointestinal tract (GIT) has been developed for use in internal dose estimations to the wall of the GIT and to the other organs and tissues of the body from radionuclides deposited in the lumenal contents of the five sections of the GIT. These sections were the esophasgus, stomach, small intestine, upper large intestine, and the lower large intestine. The wall of each section was separated from its lumenal contents

2005-01-01

30

Human placental alkaline phosphatase in liver and intestine  

Energy Technology Data Exchange (ETDEWEB)

Three distinct forms of human alkaline phosphatase, presumably isozymes, are known, each apparently associated with a specific tissue. These are placental, intestinal, and liver (kidney and bone). The authors have used a specific immunoassay and HPLC to show that placental alkaline phosphatase is also present in extracts of liver and intestine in appreciable amounts.

Garattini, E.; Margolis, J.; Heimer, E.; Felix, A.; Udenfriend, S.

1985-09-01

31

Drug Transport and Metabolism in Rat and Human Intestine  

Digital Repository Infrastructure Vision for European Research (DRIVER)

One of the aims of this thesis was to investigate the involvement of efflux proteins, such as the P-glycoprotein (Pgp), in the drug transport in different regions of the rat and the human intestine. The intestinal extrusion of intracellularly formed CYP3A4 metabolites, including whether this extr...

Berggren, Sofia

32

Effect of diet fiber and intestinal bacteria on human body  

UK PubMed Central (United Kingdom)

Relation of intergrowth and prey of good bacteria and maleficent bacteria in human body have and effect for body health. Maleficent bacteria can cause mass toxin,when maleficent bacteria of intestinal ecosystem take absoluteness vantage,can cause grave disease for body organ. Fod fiber may accelerate increase of good bacteia,and withholdmaleficent bacteria. Text by studying inner factor intestinal bacteria and external factor food fiber in metabolism of human body,it is discussed and analyzed the interactive relationship of interinhibitive amount of food fiber and the species and number of intestinal bacteria,and epounds importance of both for human body in metabolism.

Xing Shuwen; Jiao Dezhi

2003-01-01

33

Adhesion of enteropathogenic Escherichia coli to human intestinal enterocytes and cultured human intestinal mucosa.  

UK PubMed Central (United Kingdom)

The adhesion of classic enteropathogenic Escherichia coli (EPEC) strains of human origin to isolated human small intestinal enterocytes and cultured small intestinal mucosa was investigated. An adhesion assay with isolated human enterocytes prepared from duodenal biopsy samples was developed and tested with EPEC strains known to cause diarrhea in healthy adult volunteers. In the assay a mean of 53 and 55% of enterocytes had brush border-adherent E. coli E2348 (O127;H6) and E851 (O142:H6), respectively, whereas the value for a nonpathogenic control strain and a plasmid-cured derivative of strain E2348 was 0%. A collection of 17 EPEC strains was also tested for the ability to colonize cultured human duodenal mucosa. Extensive colonization occurred with 13 strains, including serogroups O55, O86, O111, O114, O119, O127, O128, and O142; and in each case electron microscopic examination of colonized mucosa revealed the characteristic histopathological lesion reported by others in natural and experimental EPEC infections. EPEC strains were seen to adhere intimately to the enterocyte surface, causing localized destruction of microvilli. The plasmid-cured derivative of strain E2348, which colonized cultured mucosa much less efficiently than the parent strain, nevertheless produced an identical lesion, indicating that plasmid-encoded factors are not essential for adhesion and the brush border-damaging property of EPEC.

Knutton S; Lloyd DR; McNeish AS

1987-01-01

34

Water and sodium absorption in the human intestine.  

UK PubMed Central (United Kingdom)

1. Studies are reported of total intestinal perfusion in man in which data relating to the absorptive capacity for water and sodium, flow rate transit time and intestinal volume have been obtained.2. A 'bolus' of radiosodium added to the steady-state perfusion has allowed measurement of bidirectional fluxes of sodium ion across the mucosa to be determined.3. The values obtained agree closely with those that can be predicted from small segmental studies reported in the literature.4. Increasing absorption capacity with increasing flow rate does not seem to reflect a true increase in absorption per unit of intestine but rather a progression to more nearly continuous flow conditions.

Love AH; Mitchell TG; Phillips RA

1968-03-01

35

Prostacyclin inhibits gastric emptying and small-intestinal transit in rats and dogs  

International Nuclear Information System (INIS)

Prostacyclin (PGI2) antagonizes 16,16-dimethyl prostaglandin E2-induced diarrhea in rats, presumably by inhibiting the fluid accumulation of ''enteropooling'' in the small intestine. The effect of PGI2 on gastric emptying, small intestinal transit, and colonic transit was examined in rats and dogs to determine if interference with propulsion might also contribute to the antidiarrheal properties of this compound. Rats implanted with chronic duodenal cannulas were given subcutaneous PGI2 (0.1-1000 microgram/kg) followed 10 min later by intragastric 2Cr and a visually detectable duodenal transit marker. Forty-five minutes later, the animals were killed. Subcutaneous PGI2 inhibited gastric emptying maximally at 10 micrograms/kg. Small-intestinal transit was significantly decreased at 50 micrograms/kg and almost completely suppressed at 1.0 mg/kg. Subcutaneous naloxone (0.5 mg/kg) given 10 min before and 20 min after subcutaneous PGI2 administration did not block PGI2's effects. Intravenous or oral PGI2, had none of these effects. Small intestinal transit was only decreased by PGI2 infusion, suggesting that this parameter was more sensitive to a sustained blood level than gastric emptying. Hourly injections of subcutaneous PGI2 (0.5 mg/kg) had no effect on rat colonic transit measured over a 3-h period after deposition of the transit marker through a colonic cannula in a manner similar to that described for small-intestinal transit above. Small-intestinal transit was also measured in dogs given a barium suspension through a chronic duodenal cannula. In vehicle-treated dogs, barium reached the cecal area in an average of 2.8 h after instillation. In PGI2-treated dogs, barium never reached the cecum in the 5-h examination period. Thus, PGI2 inhibits gastric emptying in rat and small-intestinal transit in rat and dog but has no effect on rat colonic transit

1984-01-01

36

Human intestinal spirochaetosis in northern Japan.  

UK PubMed Central (United Kingdom)

A histological diagnosis of human intestinal spirochaetosis (HIS) was made in 114 patients during the period 1994-2007. All patients lived in three prefectures in the northern part of Honshu, Japan. Most patients were elderly and male. Twenty-nine patients complained of abdominal pain, bloody stools, diarrhoea or bowel symptoms, but most patients showed no direct symptoms of bowel disease, and occult faecal blood detected at medical check-up was the main reason for colonoscopic examination. There were no homosexual patients and no immunosuppressed patients. HIS was evenly distributed throughout the whole colorectum. PCR analysis of Brachyspira aalborgi and Brachyspira pilosicoli revealed that more patients were infected with B. aalborgi. Follow-up PCR studies confirmed that infestation with B. aalborgi could be repeatedly detected over a 6 year period. This study, involving over 100 patients, identified the characteristic features of HIS in northern Japan. The results suggest that these spirochaetes may be harmless commensals that cause no obvious pathological alterations in infected individuals.

Sato H; Nakamura S; Habano W; Wakabayashi G; Adachi Y

2010-07-01

37

Human intestinal spirochaetosis in northern Japan.  

Science.gov (United States)

A histological diagnosis of human intestinal spirochaetosis (HIS) was made in 114 patients during the period 1994-2007. All patients lived in three prefectures in the northern part of Honshu, Japan. Most patients were elderly and male. Twenty-nine patients complained of abdominal pain, bloody stools, diarrhoea or bowel symptoms, but most patients showed no direct symptoms of bowel disease, and occult faecal blood detected at medical check-up was the main reason for colonoscopic examination. There were no homosexual patients and no immunosuppressed patients. HIS was evenly distributed throughout the whole colorectum. PCR analysis of Brachyspira aalborgi and Brachyspira pilosicoli revealed that more patients were infected with B. aalborgi. Follow-up PCR studies confirmed that infestation with B. aalborgi could be repeatedly detected over a 6 year period. This study, involving over 100 patients, identified the characteristic features of HIS in northern Japan. The results suggest that these spirochaetes may be harmless commensals that cause no obvious pathological alterations in infected individuals. PMID:20378723

Sato, Hajime; Nakamura, Shin-ichi; Habano, Wataru; Wakabayashi, Go; Adachi, Yoshikazu

2010-04-08

38

Two submucosal nerve plexus in human intestines.  

UK PubMed Central (United Kingdom)

We examined the architecture of human submucosal nerve networks of gut segments derived from 12 individuals (each six from small and large intestines). Twelve undivided submucosal wholemounts were prepared and immunohistochemically stained for peripherin (nerve elements) and for alpha-smooth muscle actin (remnants of attached muscle bundles). We found two ganglionic nerve networks. The plexus submucosus externus was generally monolayered and located under the outermost surface of the submucosal wholemounts. Its nerve fibre strands frequently joined each other in acute or obtuse angles, the meshes of the network were relatively wide and frequently polyangular shaped. The plexus submucosus internus was generally multi-(mostly two- or three-)layered and occupied at least the inner half of the thickness of the wholemount, sometimes extending abluminally beyond the great submucosal vessels. Its meshes were irregular. The shapes of ganglia of the two plexus were generally different, those of the internal plexus were frequently grape-like whereas the neurons of external ganglia were mostly embedded in the contoures of the joining nerve fibres. Both plexus were intensely connected via coiled interconnecting strands, either with or without intercalated ganglia. For use of eponyms for two different submucosal plexus, the names of Meissner (inner) and Schabadasch (outer) are historically justified.

Brehmer A; Rupprecht H; Neuhuber W

2010-02-01

39

Human intestinal microbiota and type 1 diabetes.  

Science.gov (United States)

The role of intestinal microbiota in immune-mediated diseases, such as type 1 diabetes, has deservedly received a lot of attention. Evidently, changes in the intestinal microbiota are associated with type 1 diabetes as demonstrated by recent studies. Children with beta-cell autoimmunity have shown low abundance of butyrate-producing bacteria and increase in the abundance of members of the Bacteroidetes phylum in fecal microbiota. These alterations could explain increased gut permeability, subclinical small intestinal inflammation, and dysregulation of oral tolerance in type 1 diabetes. However, these studies do not provide evidence of the causative role of the gut microbiota in the development of beta-cell autoimmunity, yet. In animal models, the composition of gut microbiota modulates the function of both innate and adaptive immunity, and intestinal bacteria are regulators of autoimmune diabetes. Thus, prevention of type 1 diabetes could, in the future, be based on the interventions targeted to the gut microbiota. PMID:23934614

Vaarala, Outi

2013-10-01

40

Human intestinal microbiota and type 1 diabetes.  

UK PubMed Central (United Kingdom)

The role of intestinal microbiota in immune-mediated diseases, such as type 1 diabetes, has deservedly received a lot of attention. Evidently, changes in the intestinal microbiota are associated with type 1 diabetes as demonstrated by recent studies. Children with beta-cell autoimmunity have shown low abundance of butyrate-producing bacteria and increase in the abundance of members of the Bacteroidetes phylum in fecal microbiota. These alterations could explain increased gut permeability, subclinical small intestinal inflammation, and dysregulation of oral tolerance in type 1 diabetes. However, these studies do not provide evidence of the causative role of the gut microbiota in the development of beta-cell autoimmunity, yet. In animal models, the composition of gut microbiota modulates the function of both innate and adaptive immunity, and intestinal bacteria are regulators of autoimmune diabetes. Thus, prevention of type 1 diabetes could, in the future, be based on the interventions targeted to the gut microbiota.

Vaarala O

2013-10-01

 
 
 
 
41

Blimp1 regulates the transition of neonatal to adult intestinal epithelium.  

Science.gov (United States)

In many mammalian species, the intestinal epithelium undergoes major changes that allow a dietary transition from mother's milk to the adult diet at the end of the suckling period. These complex developmental changes are the result of a genetic programme intrinsic to the gut tube, but its regulators have not been identified. Here we show that transcriptional repressor B lymphocyte-induced maturation protein 1 (Blimp1) is highly expressed in the developing and postnatal intestinal epithelium until the suckling to weaning transition. Intestine-specific deletion of Blimp1 results in growth retardation and excessive neonatal mortality. Mutant mice lack all of the typical epithelial features of the suckling period and are born with features of an adult-like intestine. We conclude that the suckling to weaning transition is regulated by a single transcriptional repressor that delays epithelial maturation. PMID:21878906

Muncan, Vanesa; Heijmans, Jarom; Krasinski, Stephen D; Büller, Nikè V; Wildenberg, Manon E; Meisner, Sander; Radonjic, Marijana; Stapleton, Kelly A; Lamers, Wout H; Biemond, Izak; van den Bergh Weerman, Marius A; O'Carroll, Dónal; Hardwick, James C; Hommes, Daniel W; van den Brink, Gijs R

2011-08-30

42

Blimp1 regulates the transition of neonatal to adult intestinal epithelium.  

UK PubMed Central (United Kingdom)

In many mammalian species, the intestinal epithelium undergoes major changes that allow a dietary transition from mother's milk to the adult diet at the end of the suckling period. These complex developmental changes are the result of a genetic programme intrinsic to the gut tube, but its regulators have not been identified. Here we show that transcriptional repressor B lymphocyte-induced maturation protein 1 (Blimp1) is highly expressed in the developing and postnatal intestinal epithelium until the suckling to weaning transition. Intestine-specific deletion of Blimp1 results in growth retardation and excessive neonatal mortality. Mutant mice lack all of the typical epithelial features of the suckling period and are born with features of an adult-like intestine. We conclude that the suckling to weaning transition is regulated by a single transcriptional repressor that delays epithelial maturation.

Muncan V; Heijmans J; Krasinski SD; Büller NV; Wildenberg ME; Meisner S; Radonjic M; Stapleton KA; Lamers WH; Biemond I; van den Bergh Weerman MA; O'Carroll D; Hardwick JC; Hommes DW; van den Brink GR

2011-01-01

43

Fusion between hematopoietic and epithelial cells in adult human intestine.  

UK PubMed Central (United Kingdom)

Following transplantation of hematopoietic lineage cells, genetic markers unique to the transplanted cells have been detected in non-hematopoietic recipient cells of human liver, vascular endothelium, intestinal epithelium and brain. The underlying mechanisms by which this occurs are unclear. Evidence from mice suggests it is due in part to fusion between cells of hematopoietic and non-hematopoietic origins; however, direct evidence for this in humans is scant. Here, by quantitative and statistical analysis of X- and Y-chromosome numbers in epithelial and non-epithelial intestinal cells from gender-mismatched hematopoietic cell transplant patients, we provide evidence that transplanted cells of the hematopoietic lineage incorporate into human intestinal epithelium through cell fusion. This is the first definitive identification of cell fusion between hematopoietic cells and any epithelial cell type in humans, and provides the basis for further understanding the physiological and potential pathological consequences of cell fusion in humans.

Silk AD; Gast CE; Davies PS; Fakhari FD; Vanderbeek GE; Mori M; Wong MH

2013-01-01

44

Distribution of vasoactive intestinal polypeptide and substance P receptors in human colon and small intestine  

International Nuclear Information System (INIS)

Vasoactive intestinal polypeptide (VIP) and substance P are found in neurons in the lamina propria and submucosa and muscularis propria of human small intestine and colon. VIP receptors coupled to adenylate cyclase are present on epithelial, smooth muscle, and mononuclear cells. This study analyzes the distribution of [125I]VIP binding and [125I]substance P in human colon and small intestine using autoradiographic techniques. [125I]VIP binding was present in high density in the mucosal layer of colon and small intestine. [125I]VIP binding was not significantly greater than nonspecific binding in smooth muscle layers or the lymphoid follicles. In contrast, [125I]substance P binding was present in high density over the colonic muscle but was not present over the mucosal layer. In human colon cancer, [125I]VIP grain density over the malignant tissue was only slightly higher than background. These autoradiographic studies of [125I]VIP binding indicate that the highest density of VIP receptors was found in the small intestine and superficial colonic mucosa, whereas the density of substance P receptors was highest over the smooth muscle layers. These findings suggest a mismatch between immunochemical content of the peptide and autoradiographic density of the receptor

1989-01-01

45

Distribution of vasoactive intestinal polypeptide and substance P receptors in human colon and small intestine  

Energy Technology Data Exchange (ETDEWEB)

Vasoactive intestinal polypeptide (VIP) and substance P are found in neurons in the lamina propria and submucosa and muscularis propria of human small intestine and colon. VIP receptors coupled to adenylate cyclase are present on epithelial, smooth muscle, and mononuclear cells. This study analyzes the distribution of (/sup 125/I)VIP binding and (/sup 125/I)substance P in human colon and small intestine using autoradiographic techniques. (/sup 125/I)VIP binding was present in high density in the mucosal layer of colon and small intestine. (/sup 125/I)VIP binding was not significantly greater than nonspecific binding in smooth muscle layers or the lymphoid follicles. In contrast, (/sup 125/I)substance P binding was present in high density over the colonic muscle but was not present over the mucosal layer. In human colon cancer, (/sup 125/I)VIP grain density over the malignant tissue was only slightly higher than background. These autoradiographic studies of (/sup 125/I)VIP binding indicate that the highest density of VIP receptors was found in the small intestine and superficial colonic mucosa, whereas the density of substance P receptors was highest over the smooth muscle layers. These findings suggest a mismatch between immunochemical content of the peptide and autoradiographic density of the receptor.

Korman, L.Y.; Sayadi, H.; Bass, B.; Moody, T.W.; Harmon, J.W.

1989-07-01

46

Tocotrienols have potent antifibrogenic effects in human intestinal fibroblasts.  

UK PubMed Central (United Kingdom)

BACKGROUND: Excessive fibroblast expansion and extracellular matrix (ECM) deposition are key events for the development of bowel stenosis in Crohn's disease (CD) patients. Tocotrienols are vitamin E compounds with proven in vitro antifibrogenic effects on rat pancreatic fibroblasts. We aimed at investigating the effects of tocotrienols on human intestinal fibroblast (HIF) proliferation, apoptosis, autophagy, and synthesis of ECM. METHODS: HIF isolated from CD, ulcerative colitis (UC), and normal intestine were treated with tocotrienol-rich fraction (TRF) from palm oil. HIF proliferation was quantified by (3) H-thymidine incorporation, apoptosis was studied by DNA fragmentation, propidium iodide staining, caspase activation, and poly(ADP-ribose) polymerase cleavage, autophagy was analyzed by quantification of LC3 protein and identification of autophagic vesicles by immunofluorescence and production of ECM components was measured by Western blot. RESULTS: TRF significantly reduced HIF proliferation and prevented basic fibroblast growth factor-induced proliferation in CD and UC, but not control HIF. TRF enhanced HIF death by promoting apoptosis and autophagy. HIF apoptosis, but not autophagy, was prevented by the pan-caspase inhibitor zVAD-fmk, whereas both types of cell death were prevented when the mitochondrial permeability transition pore was blocked by cyclosporin A, demonstrating a key role of the mitochondria in these processes. TRF diminished procollagen type I and laminin ?-1 production by HIF. CONCLUSIONS: Tocotrienols exert multiple effects on HIF, reducing cell proliferation, enhancing programmed cell death through apoptosis and autophagy, and decreasing ECM production. Considering their in vitro antifibrogenic properties, tocotrienols could be useful to treat or prevent bowel fibrosis in CD patients.

Luna J; Masamunt MC; Rickmann M; Mora R; España C; Delgado S; Llach J; Vaquero E; Sans M

2011-03-01

47

Generating human intestinal tissue from pluripotent stem cells in vitro.  

Science.gov (United States)

Here we describe a protocol for generating 3D human intestinal tissues (called organoids) in vitro from human pluripotent stem cells (hPSCs). To generate intestinal organoids, pluripotent stem cells are first differentiated into FOXA2(+)SOX17(+) endoderm by treating the cells with activin A for 3 d. After endoderm induction, the pluripotent stem cells are patterned into CDX2(+) mid- and hindgut tissue using FGF4 and WNT3a. During this patterning step, 3D mid- or hindgut spheroids bud from the monolayer epithelium attached to the tissue culture dish. The 3D spheroids are further cultured in Matrigel along with prointestinal growth factors, and they proliferate and expand over 1-3 months to give rise to intestinal tissue, complete with intestinal mesenchyme and epithelium comprising all of the major intestinal cell types. To date, this is the only method for efficiently directing the differentiation of hPSCs into 3D human intestinal tissue in vitro. PMID:22082986

McCracken, Kyle W; Howell, Jonathan C; Wells, James M; Spence, Jason R

2011-11-10

48

Effect of dextromethorphan and levomethorphan on gastric emptying and intestinal transit in the rat.  

UK PubMed Central (United Kingdom)

Dextromethorphan and levomethorphan were evaluated using 51Cr as a marker for their effects on gastric emptying and intestinal transit in the rat. Levomethorphan at 10 mg/kg i.p. and 10 and 50 mg/kg p.o. significantly (P less than or equal to .05) inhibited gastric emptying; dextromethorphan did not inhibit gastric emptying at p.o. doses up to 100 mg/kg or i.p. doses up to 10 mg/kg. Naloxone (1 mg/kg i.p.) significantly antagonized the effect of p.o. levomethorphan (50 mg/kg). Levomethorphan (10 and 50 mg/kg p.o. and 1 and 10 mg/kg i.p.) significantly inhibited intestinal transit. Dextromethorphan significantly inhibited intestinal transit after p.o. (10, 50, 100, 200 mg/kg) and i.p. (50 mg/kg) administration. As in the case of gastric emptying, naloxone inhibited the effect of levomethorphan but did not alter the effect of dextromethorphan. Naloxone itself (1 mg/kg i.p.) did not affect gastric emptying or intestinal transit. The results suggest that levomethorphan exerts inhibitory effects on intestinal transit and gastric emptying that are probably mediated partly through an opiate mechanism whereas the effects of dextromethorphan may be mediated through a nonopiate mechanism of action.

Gaginella TS; Bertko RJ; Kachur JF

1987-02-01

49

Imprint cytology detects floating Brachyspira in human intestinal spirochetosis.  

UK PubMed Central (United Kingdom)

Human intestinal spirochetosis is a colorectal infectious disease caused by 2 Brachyspira species. Its diagnosis is established by histology, culture, and polymerase chain reaction, but the value of cytologic examination in routine practice remains unclear. In this study, imprint cytology of biopsy specimens was examined for cytologic features specific to human intestinal spirochetosis. Specimens were obtained from 65 colorectal regions (1-3 regions from each case) in 25 ultrastructurally and/or genetically confirmed human intestinal spirochetosis cases (20 with Brachyspira aalborgi, 3 with B pilosicoli, 2 with both genotypes). In cytologic specimens, spirochetes tended to be floating freely within the mucus and intestinal fluid, whereas the "fringe formation" of spirochetes typically observed in histologic specimens was indistinct in cytologic specimens. Spirochetes were identified in 58 regions (89.2%) and 23 cases (92.0%) by cytology, against in 50 regions (76.9%) and 22 cases (88.0%) by histology (no significant differences). In 6 of 8 regions exhibiting positive cytology and negative histology, B pilosicoli was present within the mucus. Hence, B pilosicoli may tend to float in the mucus. In conclusion, cytologic examination would be useful for the routine identification of human intestinal spirochetosis, especially if B pilosicoli is involved. Further, we suggest the existence of differences in biological behavior between these spirochetes.

Ogata S; Higashiyama M; Adachi Y; Ohara I; Nishiyama J; Okusa Y; Takeo H; Sato K; Nakanishi K; Kawai T

2010-02-01

50

Imprint cytology detects floating Brachyspira in human intestinal spirochetosis.  

Science.gov (United States)

Human intestinal spirochetosis is a colorectal infectious disease caused by 2 Brachyspira species. Its diagnosis is established by histology, culture, and polymerase chain reaction, but the value of cytologic examination in routine practice remains unclear. In this study, imprint cytology of biopsy specimens was examined for cytologic features specific to human intestinal spirochetosis. Specimens were obtained from 65 colorectal regions (1-3 regions from each case) in 25 ultrastructurally and/or genetically confirmed human intestinal spirochetosis cases (20 with Brachyspira aalborgi, 3 with B pilosicoli, 2 with both genotypes). In cytologic specimens, spirochetes tended to be floating freely within the mucus and intestinal fluid, whereas the "fringe formation" of spirochetes typically observed in histologic specimens was indistinct in cytologic specimens. Spirochetes were identified in 58 regions (89.2%) and 23 cases (92.0%) by cytology, against in 50 regions (76.9%) and 22 cases (88.0%) by histology (no significant differences). In 6 of 8 regions exhibiting positive cytology and negative histology, B pilosicoli was present within the mucus. Hence, B pilosicoli may tend to float in the mucus. In conclusion, cytologic examination would be useful for the routine identification of human intestinal spirochetosis, especially if B pilosicoli is involved. Further, we suggest the existence of differences in biological behavior between these spirochetes. PMID:19836054

Ogata, Sho; Higashiyama, Masaaki; Adachi, Yoshikazu; Ohara, Ichiyo; Nishiyama, Junichiro; Okusa, Yasushi; Takeo, Hiroaki; Sato, Kimiya; Nakanishi, Kuniaki; Kawai, Toshiaki

2010-02-01

51

Human and rat intestinal plasma membrane calcium pump isoforms.  

UK PubMed Central (United Kingdom)

The intestinal basolateral membrane Ca(2+)-transporting adenosinetriphosphatase is the energy-dependent step in the absorption of dietary Ca2+ by the vitamin D-dependent transcellular pathway. Multiple plasma membrane Ca(2+)-pump isoforms are produced from four genes (PMCA1 to 4) and alternative mRNA splicing. We have studied which isoforms are detectable in adult human and rat gastrointestinal tissues by polymerase chain reaction (PCR) amplification, sequencing, and blotting. PMCA1 was the predominant gene product amplified from human small intestinal mucosa, although a minor additional variant lacking the exon at splice site B was detected, which resembled that described for PMCA4. Of the variants described at site C, only the shortest transcript of PMCA1 was amplified; both previously described forms of PMCA4 were found, particularly in colon where PMCA4 predominated. From rat intestinal cDNA, mixed primer PCR amplified PMCA1 and a novel sequence, the rat PMCA4 homologue, which was expressed in many tissues including small intestinal muscle and colon. However, PMCA1 was overwhelmingly predominant in the mucosa of the small intestine, being most abundant in duodenum. These results suggest the involvement of the Ca(2+)-pump isoform PMCA1b in intestinal Ca2+ absorption.

Howard A; Legon S; Walters JR

1993-11-01

52

Effect of heat stress on intestinal barrier function of human intestinal epithelial Caco-2 cells  

Directory of Open Access Journals (Sweden)

Full Text Available Objective?To investigate the heat stress-induced dysfunction of intestinal barrier including intestinal tight junction and apoptosis of epithelial cells. Methods?Human intestinal epithelial Caco-2 cell monolayers, serving as the intestinal barrier model, were exposed to different temperature (37-43?) for designated time. Transepithelial electrical resistance (TEER) and horseradish peroxidase (HRP) flux permeability were measured to evaluate barrier integrity. Level of tight junction (TJ) protein occludin was analyzed by Western blotting. Cell apoptosis rate was determined using Annexin V-FITC/PI kit by flow cytometry. Results?Compared with the 37? group, TEER lowered and the permeability for HRP increased significantly after heat exposure (P<0.01) in 39?, 41? and 43? groups. The expression of occludin increased when the temperature was elevated from 37? to 41?, and it reached the maximal level at 41?. However, its expression gradually decreased with passage of time at 43?. Cell apoptosis was enhanced with elevation of the temperature (P?0.05 or P?0.01). Conclusion?Heat stress can induce damage to tight junction and enhance apoptosis of epithelial cells, thus causing dysfunction of intestinal epithelial barrier.

Gui-zhen XIAO; Fang-fang YUAN; Zheng-tao GU; Zhi-feng LIU; Ya-li ZHANG; Lei SU

2013-01-01

53

Intestinal-fatty acid binding protein and lipid transport in human intestinal epithelial cells  

International Nuclear Information System (INIS)

Intestinal-fatty acid binding protein (I-FABP) is a 14-15 kDa cytoplasmic molecule highly expressed in the enterocyte. Although different functions have been proposed for various FABP family members, the specific function of I-FABP in human intestine remains unclear. Here, we studied the role of I-FABP in molecularly modified normal human intestinal epithelial cells (HIEC-6). cDNA transfection resulted in 90-fold I-FABP overexpression compared to cells treated with empty pQCXIP vector. The high-resolution immunogold technique revealed labeling mainly in the cytosol and confirmed the marked phenotype abundance of I-FABP in cDNA transfected cells. I-FABP overexpression was not associated with alterations in cell proliferation and viability. Studies using these transfected cells cultured with [14C]oleic acid did not reveal higher efficiency in de novo synthesis or secretion of triglycerides, phospholipids, and cholesteryl esters compared to cells treated with empty pQCXIP vector only. Similarly, the incubation with [35S]methionine did not disclose a superiority in the biogenesis of apolipoproteins (apo) A-I, A-IV, B-48, and B-100. Finally, cells transfected with I-FABP did not exhibit an increased production of chylomicrons, VLDL, LDL, and HDL. Our observations establish that I-FABP overexpression in normal HIEC-6 is not related to cell proliferation, lipid esterification, apo synthesis, and lipoprotein assembly, and, therefore, exclude its role in intestinal fat transport.

2006-01-06

54

Human intestinal spirochetosis - a review Intestinale Spirochätose des Menschen - ein Review  

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Human intestinal spirochetosis (IS) is a condition defined histologically by the presence of spirochetal microorganisms attached to the apical cell membrane of the colorectal epithelium. Intestinal spirochetes comprise a heterogeneous group of bacteria. In humans, Brachyspira aalborgi and Brachyspi...

Tsinganou, E; Gebbers, JO

55

Quantitation of small intestinal permeability during normal human drug absorption.  

UK PubMed Central (United Kingdom)

BACKGROUND: Understanding the quantitative relationship between a drug's physical chemical properties and its rate of intestinal absorption (QSAR) is critical for selecting candidate drugs. Because of limited experimental human small intestinal permeability data, approximate surrogates such as the fraction absorbed or Caco-2 permeability are used, both of which have limitations. METHODS: Given the blood concentration following an oral and intravenous dose, the time course of intestinal absorption in humans was determined by deconvolution and related to the intestinal permeability by the use of a new 3 parameter model function ("Averaged Model" (AM)). The theoretical validity of this AM model was evaluated by comparing it to the standard diffusion-convection model (DC). This analysis was applied to 90 drugs using previously published data. Only drugs that were administered in oral solution form to fasting subjects were considered so that the rate of gastric emptying was approximately known. All the calculations are carried out using the freely available routine PKQuest Java (http://www.pkquest.com) which has an easy to use, simple interface. RESULTS: Theoretically, the AM permeability provides an accurate estimate of the intestinal DC permeability for solutes whose absorption ranges from 1% to 99%. The experimental human AM permeabilities determined by deconvolution are similar to those determined by direct human jejunal perfusion. The small intestinal pH varies with position and the results are interpreted in terms of the pH dependent octanol partition. The permeability versus partition relations are presented separately for the uncharged, basic, acidic and charged solutes. The small uncharged solutes caffeine, acetaminophen and antipyrine have very high permeabilities (about 20 x 10-4?cm/sec) corresponding to an unstirred layer of only 45??m. The weak acid aspirin also has a large AM permeability despite its low octanol partition at pH?7.4, suggesting that it is nearly completely absorbed in the first part of the intestine where the pH is about 5.4. CONCLUSIONS: The AM deconvolution method provides an accurate estimate of the human intestinal permeability. The results for these 90 drugs should provide a useful benchmark for evaluating QSAR models.

Levitt DG

2013-01-01

56

Quantitation of small intestinal permeability during normal human drug absorption  

Science.gov (United States)

Background Understanding the quantitative relationship between a drug’s physical chemical properties and its rate of intestinal absorption (QSAR) is critical for selecting candidate drugs. Because of limited experimental human small intestinal permeability data, approximate surrogates such as the fraction absorbed or Caco-2 permeability are used, both of which have limitations. Methods Given the blood concentration following an oral and intravenous dose, the time course of intestinal absorption in humans was determined by deconvolution and related to the intestinal permeability by the use of a new 3 parameter model function (“Averaged Model” (AM)). The theoretical validity of this AM model was evaluated by comparing it to the standard diffusion-convection model (DC). This analysis was applied to 90 drugs using previously published data. Only drugs that were administered in oral solution form to fasting subjects were considered so that the rate of gastric emptying was approximately known. All the calculations are carried out using the freely available routine PKQuest Java (http://www.pkquest.com) which has an easy to use, simple interface. Results Theoretically, the AM permeability provides an accurate estimate of the intestinal DC permeability for solutes whose absorption ranges from 1% to 99%. The experimental human AM permeabilities determined by deconvolution are similar to those determined by direct human jejunal perfusion. The small intestinal pH varies with position and the results are interpreted in terms of the pH dependent octanol partition. The permeability versus partition relations are presented separately for the uncharged, basic, acidic and charged solutes. The small uncharged solutes caffeine, acetaminophen and antipyrine have very high permeabilities (about 20 x 10-4?cm/sec) corresponding to an unstirred layer of only 45??m. The weak acid aspirin also has a large AM permeability despite its low octanol partition at pH?7.4, suggesting that it is nearly completely absorbed in the first part of the intestine where the pH is about 5.4. Conclusions The AM deconvolution method provides an accurate estimate of the human intestinal permeability. The results for these 90 drugs should provide a useful benchmark for evaluating QSAR models.

2013-01-01

57

Adherence targets of Vibrio parahaemolyticus in human small intestines.  

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Formalin-fixed human small intestinal mucosa with mucus coating, villi, and lymphoid follicle epithelium at the mucosal surface was used to test the adherence sites of clinically isolated (Kanagawa phenomenon-positive) strains of Vibrio parahaemolyticus. V. parahaemolyticus strains grown on CFA agar...

Yamamoto, T; Yokota, T

58

Unregulated smooth-muscle myosin in human intestinal neoplasia  

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A recent study described a recessive ATPase activating germ-line mutation in smooth-muscle myosin (smmhc/myh11) underlying the zebrafish meltdown (mlt) phenotype. The mlt zebrafish develops intestinal abnormalities reminiscent of human Peutz–Jeghers syndrome (PJS) and juvenile polyposis (JP). To exa...

Alhopuro, Pia; Phichith, Denis; Tuupanen, Sari; Sammalkorpi, Heli; Nybondas, Miranda; Saharinen, Juha; Robinson, James P.

59

Decompensated Cirrhotics Have Slower Intestinal Transit Times as Compared With Compensated Cirrhotics and Healthy Controls.  

Science.gov (United States)

BACKGROUND:: Altered small intestinal motility in cirrhotics may play a major role in the development of bacterial translocation (BT) by leading to small intestinal bacterial overgrowth. BT has been implicated in the development of several complications including spontaneous bacterial peritonitis, esophageal variceal hemorrhage, and hepatorenal syndrome. Prior studies using antroduodenal manometry to evaluate intestinal motility have shown discrepancies regarding the relationship between dysmotility and the severity of cirrhosis. OBJECTIVES:: (1) To characterize the frequency of small bowel motility disturbances in cirrhotic patients using a wireless motility capsule (SmartPill); (2) To assess the relationship of intestinal dysmotility with liver disease severity and cirrhosis complications; and (3) To compare intestinal transit times and motility indices among cirrhotics and healthy controls. METHODS:: We conducted a prospective study of 20 patients with cirrhosis (10 compensated, 10 decompensated) who were recruited from Yale New Haven Hospital and Hepatology clinics (February 2011 to July 2011). All patients underwent and completed SmartPill studies. Intestinal transit times were calculated, analyzed, and compared among compensated versus decompensated cirrhotics versus historical, healthy controls. Intestinal transit delays/motility indices were correlated with disease severity and complications. RESULTS:: Decompensated cirrhotics had significantly longer small bowel transit times (SBTT) as compared with compensated cirrhotics (6.17 vs. 3.56 h, P=0.036). There was a significant correlation (r=0.77, P=0.0003) between SBTT and cirrhosis severity as assessed by Child-Pugh score. There were no statistical differences noted between the groups for gastric or colonic transit times, although there was a trend toward prolonged transit throughout the gut in decompensated. Cirrhotics with spontaneous bacterial peritonitis and ascites also had significantly longer SBTT as compared with those without. CONCLUSIONS:: This study demonstrates that decompensated cirrhotics have slower intestinal transit times as compared with compensated cirrhotics and healthy controls. Additional prospective studies are needed to further characterize dysmotility in cirrhotics and its relationship to complications related to BT. This would aid in the identification of patients at risk for developing severe complications and who may benefit from prophylactic prokinetic and/or antimicrobial therapy. PMID:23632359

Chander Roland, Bani; Garcia-Tsao, Guadalupe; Ciarleglio, Maria M; Deng, Yanhong; Sheth, Anish

2013-05-30

60

Decompensated Cirrhotics Have Slower Intestinal Transit Times as Compared With Compensated Cirrhotics and Healthy Controls.  

UK PubMed Central (United Kingdom)

BACKGROUND:: Altered small intestinal motility in cirrhotics may play a major role in the development of bacterial translocation (BT) by leading to small intestinal bacterial overgrowth. BT has been implicated in the development of several complications including spontaneous bacterial peritonitis, esophageal variceal hemorrhage, and hepatorenal syndrome. Prior studies using antroduodenal manometry to evaluate intestinal motility have shown discrepancies regarding the relationship between dysmotility and the severity of cirrhosis. OBJECTIVES:: (1) To characterize the frequency of small bowel motility disturbances in cirrhotic patients using a wireless motility capsule (SmartPill); (2) To assess the relationship of intestinal dysmotility with liver disease severity and cirrhosis complications; and (3) To compare intestinal transit times and motility indices among cirrhotics and healthy controls. METHODS:: We conducted a prospective study of 20 patients with cirrhosis (10 compensated, 10 decompensated) who were recruited from Yale New Haven Hospital and Hepatology clinics (February 2011 to July 2011). All patients underwent and completed SmartPill studies. Intestinal transit times were calculated, analyzed, and compared among compensated versus decompensated cirrhotics versus historical, healthy controls. Intestinal transit delays/motility indices were correlated with disease severity and complications. RESULTS:: Decompensated cirrhotics had significantly longer small bowel transit times (SBTT) as compared with compensated cirrhotics (6.17 vs. 3.56 h, P=0.036). There was a significant correlation (r=0.77, P=0.0003) between SBTT and cirrhosis severity as assessed by Child-Pugh score. There were no statistical differences noted between the groups for gastric or colonic transit times, although there was a trend toward prolonged transit throughout the gut in decompensated. Cirrhotics with spontaneous bacterial peritonitis and ascites also had significantly longer SBTT as compared with those without. CONCLUSIONS:: This study demonstrates that decompensated cirrhotics have slower intestinal transit times as compared with compensated cirrhotics and healthy controls. Additional prospective studies are needed to further characterize dysmotility in cirrhotics and its relationship to complications related to BT. This would aid in the identification of patients at risk for developing severe complications and who may benefit from prophylactic prokinetic and/or antimicrobial therapy.

Roland BC; Garcia-Tsao G; Ciarleglio MM; Deng Y; Sheth A

2013-04-01

 
 
 
 
61

Molecular Epidemiology of Human Intestinal Amoebas in Iran  

Directory of Open Access Journals (Sweden)

Full Text Available Many microscopic-based epidemiological surveys on the prevalence of human intestinal pathogenic and non-pathogenic protozoa including intestinal amoeba performed in Iran show a high prevalence of human intestinal amoeba in different parts of Iran. Such epidemiological studies on amoebiasis are confusing, mainly due to recently appreciated distinction between the Entamoeba histolytica, E. dispar and E. moshkovskii. Differential diagnosis can be done by some methods such as PCR-based methods, monoclonal antibodies and the analysis of isoenzyme typing, however the molecular study of these protozoa in Iran is low. Based on molecular studies, it seems that E. dispar is predominant species especially in the central and northern areas of Iran and amoebiasis due to E. histolytica is a rare infection in the country. It is suggested that infection with E. moshkovskii may be common among Iranians. Considering the importance of molecular epidemiology of amoeba in Iran and also the current data, the present study reviews the data currently available on the molecular distribution of intestinal human amoeba in Iran.

H Hooshyar; P Rostamkhani; M Rezaian

2012-01-01

62

Ricin crosses polarized human intestinal cells and intestines of ricin-gavaged mice without evident damage and then disseminates to mouse kidneys.  

UK PubMed Central (United Kingdom)

Ricin is a potent toxin found in the beans of Ricinus communis and is often lethal for animals and humans when aerosolized or injected and causes significant morbidity and occasional death when ingested. Ricin has been proposed as a bioweapon because of its lethal properties, environmental stability, and accessibility. In oral intoxication, the process by which the toxin transits across intestinal mucosa is not completely understood. To address this question, we assessed the impact of ricin on the gastrointestinal tract and organs of mice after dissemination of toxin from the gut. We first showed that ricin adhered in a specific pattern to human small bowel intestinal sections, the site within the mouse gut in which a variable degree of damage has been reported by others. We then monitored the movement of ricin across polarized human HCT-8 intestinal monolayers grown in transwell inserts and in HCT-8 cell organoids. We observed that, in both systems, ricin trafficked through the cells without apparent damage until 24 hours post intoxication. We delivered a lethal dose of purified fluorescently-labeled ricin to mice by oral gavage and followed transit of the toxin from the gastrointestinal tracts to the internal organs by in vivo imaging of whole animals over time and ex vivo imaging of organs at various time points. In addition, we harvested organs from unlabeled ricin-gavaged mice and assessed them for the presence of ricin and for histological damage. Finally, we compared serum chemistry values from buffer-treated versus ricin-intoxicated animals. We conclude that ricin transverses human intestinal cells and mouse intestinal cells in situ prior to any indication of enterocyte damage and that ricin rapidly reaches the kidneys of intoxicated mice. We also propose that mice intoxicated orally with ricin likely die from distributive shock.

Flora AD; Teel LD; Smith MA; Sinclair JF; Melton-Celsa AR; O'Brien AD

2013-01-01

63

Ricin crosses polarized human intestinal cells and intestines of ricin-gavaged mice without evident damage and then disseminates to mouse kidneys.  

Science.gov (United States)

Ricin is a potent toxin found in the beans of Ricinus communis and is often lethal for animals and humans when aerosolized or injected and causes significant morbidity and occasional death when ingested. Ricin has been proposed as a bioweapon because of its lethal properties, environmental stability, and accessibility. In oral intoxication, the process by which the toxin transits across intestinal mucosa is not completely understood. To address this question, we assessed the impact of ricin on the gastrointestinal tract and organs of mice after dissemination of toxin from the gut. We first showed that ricin adhered in a specific pattern to human small bowel intestinal sections, the site within the mouse gut in which a variable degree of damage has been reported by others. We then monitored the movement of ricin across polarized human HCT-8 intestinal monolayers grown in transwell inserts and in HCT-8 cell organoids. We observed that, in both systems, ricin trafficked through the cells without apparent damage until 24 hours post intoxication. We delivered a lethal dose of purified fluorescently-labeled ricin to mice by oral gavage and followed transit of the toxin from the gastrointestinal tracts to the internal organs by in vivo imaging of whole animals over time and ex vivo imaging of organs at various time points. In addition, we harvested organs from unlabeled ricin-gavaged mice and assessed them for the presence of ricin and for histological damage. Finally, we compared serum chemistry values from buffer-treated versus ricin-intoxicated animals. We conclude that ricin transverses human intestinal cells and mouse intestinal cells in situ prior to any indication of enterocyte damage and that ricin rapidly reaches the kidneys of intoxicated mice. We also propose that mice intoxicated orally with ricin likely die from distributive shock. PMID:23874986

Flora, Alyssa D; Teel, Louise D; Smith, Mark A; Sinclair, James F; Melton-Celsa, Angela R; O'Brien, Alison D

2013-07-17

64

Blimp1 regulates the transition of neonatal to adult intestinal epithelium  

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In many mammalian species, the intestinal epithelium undergoes major changes that allow a dietary transition from mother's milk to the adult diet at the end of the suckling period. These complex developmental changes are the result of a genetic programme intrinsic to the gut tube, but its regulators...

Muncan, Vanesa; Heijmans, Jarom; Krasinski, Stephen D.; Büller, Nikè V.; Wildenberg, Manon E.; Meisner, Sander

65

Small intestinal transit in patients with liver cirrhosis and portal hypertension : a descriptive study  

DEFF Research Database (Denmark)

Gastrointestinal dysmotility may be involved in the development of bacterial translocation and infection in patients with liver cirrhosis. The aim of the present study was to describe gastric, small intestinal and colorectal motility and transit in patients with liver cirrhosis and portal hypertension using a magnet-based Motility Tracking System (MTS-1) and standard radiopaque markers.

Karlsen, Stine; Fynne, Lotte

2012-01-01

66

Solubility Profiling of HIV Protease Inhibitors in Human Intestinal Fluids.  

UK PubMed Central (United Kingdom)

The present study pursued to profile the intestinal solubility of nine HIV protease inhibitors (PIs) in fasted- and fed-state human intestinal fluids (FaHIF, FeHIF) aspirated from four volunteers. In addition, the ability of fasted- and fed-state simulated intestinal fluids (FaSSIF, FeSSIF) to predict the intestinal solubility was evaluated. All PIs were poorly soluble in FaHIF (from 7??M for ritonavir to 327??M for darunavir) and FeHIF (from 15??M for atazanavir to 409?M for darunavir). For four of nine PIs, food intake significantly enhanced the solubilizing capacity of intestinal fluids (up to 18.4-fold increase for ritonavir). The intersubject variability (average coefficient of variance CVfed = 60.6%, CVfasted = 40.4%) was higher as compared with the intrasubject variability (CVfed = 41.3%, CVfasted = 20.5%). PI solubilities correlated reasonably well between FaSSIF and FaHIF (R = 0.817), but not between FeSSIF and FeHIF (R = 0.617). To conclude, postprandial conditions increased the inter- and intrasubject variability of the PIs. The inability of FeSSIF to accurately predict the FeHIF solubility emphasizes the need for a multivariate approach to determine solubility profiles, taking into account solid-state characteristics, pH, mixed bile acid/phospholipid micelles, and digestive products. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:3800-3807, 2013.

Wuyts B; Brouwers J; Mols R; Tack J; Annaert P; Augustijns P

2013-10-01

67

Solubility Profiling of HIV Protease Inhibitors in Human Intestinal Fluids.  

Science.gov (United States)

The present study pursued to profile the intestinal solubility of nine HIV protease inhibitors (PIs) in fasted- and fed-state human intestinal fluids (FaHIF, FeHIF) aspirated from four volunteers. In addition, the ability of fasted- and fed-state simulated intestinal fluids (FaSSIF, FeSSIF) to predict the intestinal solubility was evaluated. All PIs were poorly soluble in FaHIF (from 7??M for ritonavir to 327??M for darunavir) and FeHIF (from 15??M for atazanavir to 409?M for darunavir). For four of nine PIs, food intake significantly enhanced the solubilizing capacity of intestinal fluids (up to 18.4-fold increase for ritonavir). The intersubject variability (average coefficient of variance CVfed = 60.6%, CVfasted = 40.4%) was higher as compared with the intrasubject variability (CVfed = 41.3%, CVfasted = 20.5%). PI solubilities correlated reasonably well between FaSSIF and FaHIF (R = 0.817), but not between FeSSIF and FeHIF (R = 0.617). To conclude, postprandial conditions increased the inter- and intrasubject variability of the PIs. The inability of FeSSIF to accurately predict the FeHIF solubility emphasizes the need for a multivariate approach to determine solubility profiles, taking into account solid-state characteristics, pH, mixed bile acid/phospholipid micelles, and digestive products. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:3800-3807, 2013. PMID:23939880

Wuyts, Benjamin; Brouwers, Joachim; Mols, Raf; Tack, Jan; Annaert, Pieter; Augustijns, Patrick

2013-08-12

68

[Algorithm for the coproscopic diagnosis of human intestinal parasites].  

UK PubMed Central (United Kingdom)

The purpose of the study was to elaborate a detection algorithm for human intestinal helminth eggs. There is a broad spectrum ofcoproscopic methods recommended for the detection of Opisthorchis eggs in man and animals; these include Fulleborn's method, formalin-ether method, Goryachev's, Katoh's, Kalantaryan's, Shcherbovich's, and Kotelnikov-Varenichev methods. Combined coproscopic methods are significantly more effective in detecting the causative agents of enteric parasitoses than is Katoh's method. Among the considered coproscopic techniques for the diagnosis of human ascariasis, it is most rational to use a combined method for fecal examination, the basis for which is a multicomponent flotation system (such as the author's one). The Kotelnikov-Varenichev method is optimal for diagnosing opisthorchiasis. It is optimal to use 2-3 methods of different groups simultaneously for the screening diagnosis of intestinal parasitoses.

Dolbin DA; Tiurin IuA; Kha?rullin RM

2012-04-01

69

Human intestinal spirochetosis accompanied by human immunodeficiency virus infection: a case report.  

Science.gov (United States)

We present a middle-aged, heterosexual Japanese man with mixed infections including human intestinal spirochetosis, which led us to the detection of human immunodeficiency virus (HIV) infection. The patient had syphilis without related physical or neurological findings. An examination for the serum antibody for HIV performed 9 years previously was negative. In a complete medical checkup at the present time, human intestinal spirochetosis and unspecified entamebic cysts were suggested by histological examination of colonic biopsy material and parasitic examination of the intestinal fluid, respectively. Moreover, a serological test for the antibody for HIV was positive. In specimens obtained by colonoscopy, Brachyspira aalborgi was diagnosed by ultrastructural study and the polymerase chain reaction method for bacterial 16S ribosomal deoxyribonucleic acid. Although HIV infection remains at low prevalence in Japan, we recommend examination for HIV infection in patients with human intestinal spirochetosis, especially when other co-infections are apparent. PMID:19727207

Higashiyama, Masaaki; Ogata, Sho; Adachi, Yoshikazu; Nishiyama, Junichiro; Ohara, Ichiyo; Okamura, Meri; Matsuzaki, Koji; Okusa, Yasushi; Sato, Kimiya; Hokari, Ryota; Miura, Soichiro

2009-08-01

70

Human intestinal spirochetosis accompanied by human immunodeficiency virus infection:a case report  

Directory of Open Access Journals (Sweden)

Full Text Available We present a middle-aged, heterosexual Japanese man with mixed infections including human intestinal spirochetosis, which led us to the detection of human immunodeficiency virus (HIV) infection. The patient had syphilis without related physical or neurological findings. An examination for the serum antibody for HIV performed 9 years previously was negative. In a complete medical checkup at the present time, human intestinal spirochetosis and unspecified entamebic cysts were suggested by histological examination of colonic biopsy material and parasitic examination of the intestinal fluid, respectively. Moreover, a serological test for the antibody for HIV was positive. In specimens obtained by colonoscopy, Brachyspira aalborgi was diagnosed by ultrastructural study and the polymerase chain reaction method for bacterial 16S ribosomal deoxyribonucleic acid. Although HIV infection remains at low prevalence in Japan, we recommend examination for HIV infection in patients with human intestinal spirochetosis, especially when other co-infections are apparent.

Higashiyama,Masaaki; Ogata,Sho; Adachi,Yoshikazu; Nishiyama,Junichiro; Ohara,Ichiyo; Okamura,Meri; Matsuzaki,Koji; Okusa,Yasushi; Sato,Kimiya; Hokari,Ryota; Miura,Soichiro

2009-01-01

71

Human intestinal macrophages display profound inflammatory anergy despite avid phagocytic and bacteriocidal activity  

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Intestinal macrophages, which are thought to orchestrate mucosal inflammatory responses, have received little investigative attention compared with macrophages from other tissues. Here we show that human intestinal macrophages do not express innate response receptors, including the receptors for LPS...

Smythies, Lesley E.; Sellers, Marty; Clements, Ronald H.; Mosteller-Barnum, Meg; Meng, Gang; Benjamin, William H.

72

Scintigraphic evaluation of small intestinal transit in the streptozotocin induced diabetic rats.  

UK PubMed Central (United Kingdom)

Aim: Small intestine (SI) transit in the streptozotocin (STZ) induced diabetic rats were examined by using 99mTc-mebrofenin scintigraphy.Materials and methods: Wistar albino rats (mean body weight: 220±12 g) were studied for both control (n=10) and diabetes mellitus (DM) (n=10) groups. Diabetes was induced by a single intraperitoneal injection of streptozotocin (50 mg kg(-1) body weight. SI transit time was assessed by measuring arrival times of 99mTc-mebrofenin from duodenum to caecum.Results: The mean transit time of 99mTc- mebrofenin was 67.8±11 min in control group. The mean transit time of SI was prolonged in STZ induced diabetic animals with (111.9±12.5, p=0.01). There was significant correlation between small intestinal transit time and blood glucose level (r: 0.73, p=0.01).Conclusion: We observed that SI transit was prolonged in diabetic animals using 99mTc- mebrofenin, and additionally this technique is a readily available method for the detection of transit abnormalities in animal experiment.

Durmus-Altun G; Vatansever U; Arzu Vardar S; Altaner S; Dirlik B

2011-07-01

73

Scintigraphic evaluation of small intestinal transit in the streptozotocin induced diabetic rats.  

Science.gov (United States)

Aim: Small intestine (SI) transit in the streptozotocin (STZ) induced diabetic rats were examined by using 99mTc-mebrofenin scintigraphy.Materials and methods: Wistar albino rats (mean body weight: 220±12 g) were studied for both control (n=10) and diabetes mellitus (DM) (n=10) groups. Diabetes was induced by a single intraperitoneal injection of streptozotocin (50 mg kg(-1) body weight. SI transit time was assessed by measuring arrival times of 99mTc-mebrofenin from duodenum to caecum.Results: The mean transit time of 99mTc- mebrofenin was 67.8±11 min in control group. The mean transit time of SI was prolonged in STZ induced diabetic animals with (111.9±12.5, p=0.01). There was significant correlation between small intestinal transit time and blood glucose level (r: 0.73, p=0.01).Conclusion: We observed that SI transit was prolonged in diabetic animals using 99mTc- mebrofenin, and additionally this technique is a readily available method for the detection of transit abnormalities in animal experiment. PMID:22435026

Durmus-Altun, G; Vatansever, U; Arzu Vardar, S; Altaner, S; Dirlik, B

2011-07-01

74

Gastric emptying, small intestinal transit and fecal output in dystrophic (mdx) mice.  

UK PubMed Central (United Kingdom)

Duchenne muscular dystrophy (DMD), which results from deficiency in dystrophin, a sarcolemma protein of skeletal, cardiac and smooth muscle, is characterized by progressive striated muscle degeneration, but various gastrointestinal clinical manifestations have been observed. The aim was to evaluate the possible impact of the dystrophin loss on the gastrointestinal propulsion in mdx mice (animal model for DMD). The gastric emptying of a carboxymethyl cellulose/phenol red dye non-nutrient meal was not significantly different at 20 min from gavaging between wild-type and mdx mice. The intestinal transit and the fecal output were significantly decreased in mdx versus normal animals, although the length of the intestine was similar in both animals. The present results provide evidence for motor intestinal alterations in mdx mice in in vivo conditions.

Mulè F; Amato A; Serio R

2010-01-01

75

Halophilic archaea in the human intestinal mucosa.  

UK PubMed Central (United Kingdom)

The human gastrointestinal tract microbiota, despite its key roles in health and disease, remains a diverse, variable and poorly understood entity. Current surveys reveal a multitude of undefined bacterial taxa and a low diversity of methanogenic archaea. In an analysis of the microbiota in colonic mucosal biopsies from patients with inflammatory bowel disease we found 16S rDNA sequences representing a phylogenetically rich diversity of halophilic archaea from the Halobacteriaceae (haloarchaea), including novel phylotypes. As the human colon is not considered a salty environment and haloarchaea are described as extreme halophiles, we evaluated and further discarded the possibility that these sequences originated from pre-colonoscopy saline lavage solutions. Furthermore, aerobic enrichment cultures prepared from a patient biopsy at low salinity (2.5% NaCl) yielded haloarchaeal sequence types. Microscopic observation after fluorescence in situ hybridization provided evidence of the presence of viable archaeal cells in these cultures. These results prove the survival of haloarchaea in the digestive system and suggest that they may be members of the mucosal microbiota, even if present in low numbers in comparison with methanogenic archaea. Investigation of a potential physiological basis of this association may lead to new insights into gastrointestinal health and disease.

Oxley AP; Lanfranconi MP; Würdemann D; Ott S; Schreiber S; McGenity TJ; Timmis KN; Nogales B

2010-09-01

76

Rates of intestinal absorption of molybdenum in humans  

Energy Technology Data Exchange (ETDEWEB)

The intestinal absorption of molybdenum in healthy human volunteers has been measured by simultaneous oral and intravenous administration of the stable isotopes {sup 95}Mo and {sup 96}Mo, and the results were analysed using the convolution integral technique. The results showed that molybdenum ingested in liquid form was rapidly and totally absorbed into the circulation under ordinary intake regimes. The rates and extent of absorption were lower for composite meals, and also for increasing levels of administration. This information can be helpful in the application of the new ICRP model of the human alimentary tract.

Giussani, Augusto [Dipartimento di Fisica, Universita degli Studi di Milano, and INFN, Sezione di Milano, via Celoria 16, 20133 Milan (Italy)]. E-mail: augusto.giussani@gsf.de; Arogunjo, Adeseye M. [Department of Physics, Federal University of Technology, P.M.B. 704, Akure, Ondo State (Nigeria); Claire Cantone, Marie [Dipartimento di Fisica, Universita degli Studi di Milano, and INFN, Sezione di Milano, via Celoria 16, 20133 Milan (Italy); Tavola, Federico [Dipartimento di Fisica, Universita degli Studi di Milano, and INFN, Sezione di Milano, via Celoria 16, 20133 Milan (Italy); Veronese, Ivan [Dipartimento di Fisica, Universita degli Studi di Milano, and INFN, Sezione di Milano, via Celoria 16, 20133 Milan (Italy)

2006-06-15

77

Rates of intestinal absorption of molybdenum in humans  

International Nuclear Information System (INIS)

The intestinal absorption of molybdenum in healthy human volunteers has been measured by simultaneous oral and intravenous administration of the stable isotopes 95Mo and 96Mo, and the results were analysed using the convolution integral technique. The results showed that molybdenum ingested in liquid form was rapidly and totally absorbed into the circulation under ordinary intake regimes. The rates and extent of absorption were lower for composite meals, and also for increasing levels of administration. This information can be helpful in the application of the new ICRP model of the human alimentary tract.

2006-01-01

78

IL-2 receptor ?-chain molecule is critical for intestinal T-cell reconstitution in humanized mice  

Science.gov (United States)

Intestinal immune cells are important in host defense, yet the determinants for human lymphoid homeostasis in the intestines are poorly understood. In contrast, lymphoid homeostasis has been studied extensively in mice, where the requirement for a functional common ?-chain molecule has been established. We hypothesized that humanized mice could offer insights into human intestinal lymphoid homeostasis if generated in a strain with an intact mouse common ?-chain molecule. To address this hypothesis, we used three mouse strains (non-obese diabetic (NOD)/severe-combined immunodeficient (SCID) (N/S); NOD/SCID ?-chain?/? (NSG); and Rag2?/? ?-chain?/? (DKO)) and two humanization techniques (bone marrow liver thymus (BLT) and human CD34+ cell bone marrow transplant of newborn mice (hu)) to generate four common types of humanized mice: N/S-BLT, NSG-BLT, NSG-hu, and DKO-hu mice. The highest levels of intestinal human T cells throughout the small and large intestines were observed in N/S-BLT mice, which have an intact common ?-chain molecule. Furthermore, the small intestine lamina propria T-cell populations of N/S-BLT mice exhibit a human intestine-specific surface phenotype. Thus, the extensive intestinal immune reconstitution of N/S-BLT mice was both quantitatively and qualitatively better when compared with the other models tested such that N/S-BLT mice are well suited for the analysis of human intestinal lymphocyte trafficking and human-specific diseases affecting the intestines.

Denton, PW; Nochi, T; Lim, A; Krisko, JF; Martinez-Torres, F; Choudhary, SK; Wahl, A; Olesen, R; Zou, W; Di Santo, JP; Margolis, DM; Garcia, JV

2013-01-01

79

An iterative workflow for mining the human intestinal metaproteome  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Peptide spectrum matching (PSM) is the standard method in shotgun proteomics data analysis. It relies on the availability of an accurate and complete sample proteome that is used to make interpretation of the spectra feasible. Although this procedure has proven to be effective in many proteomics studies, the approach has limitations when applied on complex samples of microbial communities, such as those found in the human intestinal tract. Metagenome studies have indicated that the human intestinal microbiome contains over 100 times more genes than the human genome and it has been estimated that this ecosystem contains over 5000 bacterial species. The genomes of the vast majority of these species have not yet been sequenced and hence their proteomes remain unknown. To enable data analysis of shotgun proteomics data using PSM, and circumvent the lack of a defined matched metaproteome, an iterative workflow was developed that is based on a synthetic metaproteome and the developing metagenomic databases that are both representative for but not necessarily originating from the sample of interest. Results Two human fecal samples for which metagenomic data had been collected, were analyzed for their metaproteome using liquid chromatography-mass spectrometry and used to benchmark the developed iterative workflow to other methods. The results show that the developed method is able to detect over 3,000 peptides per fecal sample from the spectral data by circumventing the lack of a defined proteome without naive translation of matched metagenomes and cross-species peptide identification. Conclusions The developed iterative workflow achieved an approximate two-fold increase in the amount of identified spectra at a false discovery rate of 1% and can be applied in metaproteomic studies of the human intestinal tract or other complex ecosystems.

Rooijers Koos; Kolmeder Carolin; Juste Catherine; Doré Joël; de Been Mark; Boeren Sjef; Galan Pilar; Beauvallet Christian; de Vos Willem M; Schaap Peter J

2011-01-01

80

An iterative workflow for mining the human intestinal metaproteome  

Science.gov (United States)

Background Peptide spectrum matching (PSM) is the standard method in shotgun proteomics data analysis. It relies on the availability of an accurate and complete sample proteome that is used to make interpretation of the spectra feasible. Although this procedure has proven to be effective in many proteomics studies, the approach has limitations when applied on complex samples of microbial communities, such as those found in the human intestinal tract. Metagenome studies have indicated that the human intestinal microbiome contains over 100 times more genes than the human genome and it has been estimated that this ecosystem contains over 5000 bacterial species. The genomes of the vast majority of these species have not yet been sequenced and hence their proteomes remain unknown. To enable data analysis of shotgun proteomics data using PSM, and circumvent the lack of a defined matched metaproteome, an iterative workflow was developed that is based on a synthetic metaproteome and the developing metagenomic databases that are both representative for but not necessarily originating from the sample of interest. Results Two human fecal samples for which metagenomic data had been collected, were analyzed for their metaproteome using liquid chromatography-mass spectrometry and used to benchmark the developed iterative workflow to other methods. The results show that the developed method is able to detect over 3,000 peptides per fecal sample from the spectral data by circumventing the lack of a defined proteome without naive translation of matched metagenomes and cross-species peptide identification. Conclusions The developed iterative workflow achieved an approximate two-fold increase in the amount of identified spectra at a false discovery rate of 1% and can be applied in metaproteomic studies of the human intestinal tract or other complex ecosystems.

2011-01-01

 
 
 
 
81

Isolation of catechin-converting human intestinal bacteria.  

UK PubMed Central (United Kingdom)

AIMS: To isolate and characterize bacteria from the human intestine that are involved in the conversion of catechins, a class of bioactive polyphenols abundant in the human diet. METHODS AND RESULTS: Two bacterial strains, rK3 and aK2, were isolated from an epicatechin-converting human faecal suspension. The isolates catalysed individual steps in the degradation of ?-epicatechin and ?-catechin. Based on their phenotypic characteristics and 16S rRNA gene sequences, the isolates were identified as Eggerthella lenta and Flavonifractor plautii (formerly Clostridium orbiscindens). Eggerthella lenta rK3 reductively cleaved the heterocyclic C-ring of both ?-epicatechin and ?-catechin giving rise to 1-(3,4-dihydroxyphenyl)-3-(2,4,6-trihydroxyphenyl)propan-2-ol. The conversion of catechin proceeded five times faster than that of epicatechin. Higher (epi)catechin concentrations led to an accelerated formation of the ring fission product without affecting the growth of Eg. lenta rK3. Flavonifractor plautii aK2 further converted 1-(3,4-dihydroxyphenyl)-3-(2,4,6-trihydroxyphenyl)propan-2-ol to 5-(3,4-dihydroxyphenyl)-?-valerolactone and 4-hydroxy-5-(3,4-dihydroxyphenyl)valeric acid. Flavonifractor plautii DSM 6740 catalysed the identical reaction indicating it is not strain specific. CONCLUSIONS: The conversion of dietary catechins by the isolated Eg. lenta and F. plautii strains in the human intestine may affect their bioavailability. SIGNIFICANCE AND IMPACT OF THE STUDY: The majority of catechin metabolites are generated by the intestinal microbiota. The identification of catechin-converting gut bacteria therefore contributes to the elucidation of the bioactivation and the health effects of catechins.

Kutschera M; Engst W; Blaut M; Braune A

2011-07-01

82

Functional Metagenomic Investigations of the Human Intestinal Microbiota  

Science.gov (United States)

The human intestinal microbiota encode multiple critical functions impacting human health, including metabolism of dietary substrate, prevention of pathogen invasion, immune system modulation, and provision of a reservoir of antibiotic resistance genes accessible to pathogens. The complexity of this microbial community, its recalcitrance to standard cultivation, and the immense diversity of its encoded genes has necessitated the development of novel molecular, microbiological, and genomic tools. Functional metagenomics is one such culture-independent technique, used for decades to study environmental microorganisms, but relatively recently applied to the study of the human commensal microbiota. Metagenomic functional screens characterize the functional capacity of a microbial community, independent of identity to known genes, by subjecting the metagenome to functional assays in a genetically tractable host. Here we highlight recent work applying this technique to study the functional diversity of the intestinal microbiota, and discuss how an approach combining high-throughput sequencing, cultivation, and metagenomic functional screens can improve our understanding of interactions between this complex community and its human host.

Moore, Aimee M.; Munck, Christian; Sommer, Morten O. A.; Dantas, Gautam

2011-01-01

83

Human milk hyaluronan enhances innate defense of the intestinal epithelium.  

UK PubMed Central (United Kingdom)

Breast-feeding is associated with enhanced protection from gastrointestinal disease in infants, mediated in part by an array of bioactive glycan components in milk that act through molecular mechanisms to inhibit enteric pathogen infection. Human milk contains hyaluronan (HA), a glycosaminoglycan polymer found in virtually all mammalian tissues. We have shown that synthetic HA of a specific size range promotes expression of antimicrobial peptides in intestinal epithelium. We hypothesize that hyaluronan from human milk also enhances innate antimicrobial defense. Here we define the concentration of HA in human milk during the first 6 months postpartum. Importantly, HA isolated from milk has a biological function. Treatment of HT-29 colonic epithelial cells with human milk HA at physiologic concentrations results in time- and dose-dependent induction of the antimicrobial peptide human ?-defensin 2 and is abrogated by digestion of milk HA with a specific hyaluronidase. Milk HA induction of human ?-defensin 2 expression is also reduced in the presence of a CD44-blocking antibody and is associated with a specific increase in ERK1/2 phosphorylation, suggesting a role for the HA receptor CD44. Furthermore, oral administration of human milk-derived HA to adult, wild-type mice results in induction of the murine H? D2 ortholog in intestinal mucosa and is dependent upon both TLR4 and CD44 in vivo. Finally, treatment of cultured colonic epithelial cells with human milk HA enhances resistance to infection by the enteric pathogen Salmonella typhimurium. Together, our observations suggest that maternally provided HA stimulates protective antimicrobial defense in the newborn.

Hill DR; Rho HK; Kessler SP; Amin R; Homer CR; McDonald C; Cowman MK; de la Motte CA

2013-10-01

84

Cell dedifferentiation and epithelial to mesenchymal transitions during intestinal regeneration in H. glaberrima  

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Full Text Available Abstract Background Determining the type and source of cells involved in regenerative processes has been one of the most important goals of researchers in the field of regeneration biology. We have previously used several cellular markers to characterize the cells involved in the regeneration of the intestine in the sea cucumber Holothuria glaberrima. Results We have now obtained a monoclonal antibody that labels the mesothelium; the outer layer of the gut wall composed of peritoneocytes and myocytes. Using this antibody we studied the role of this tissue layer in the early stages of intestinal regeneration. We have now shown that the mesothelial cells of the mesentery, specifically the muscle component, undergo dedifferentiation from very early on in the regeneration process. Cell proliferation, on the other hand, increases much later, and mainly takes place in the mesothelium or coelomic epithelium of the regenerating intestinal rudiment. Moreover, we have found that the formation of the intestinal rudiment involves a novel regenerative mechanism where epithelial cells ingress into the connective tissue and acquire mesenchymal phenotypes. Conclusions Our results strongly suggest that the dedifferentiating mesothelium provides the initial source of cells for the formation of the intestinal rudiment. At later stages, cell proliferation supplies additional cells necessary for the increase in size of the regenerate. Our data also shows that the mechanism of epithelial to mesenchymal transition provides many of the connective tissue cells found in the regenerating intestine. These results present some new and important information as to the cellular basis of organ regeneration and in particular to the process of regeneration of visceral organs.

García-Arrarás José E; Valentín-Tirado Griselle; Flores Jaime E; Rosa Rey J; Rivera-Cruz Angélica; San Miguel-Ruiz José E; Tossas Karen

2011-01-01

85

Glutathione transport system in human small intestine epithelial cells.  

Science.gov (United States)

The present study characterizes for the first time a GSH specific transporter in a human intestinal epithelial cell line (I407). GSH metabolism is very important for the antioxidant and detoxifying action of intestine and for the maintenance of the luminal thiol-disulfide ratio involved in regulation mechanisms of the protein activity of epithelial cells. GSH level decreases have been related to physio-pathological alterations either of intestine or other organs. GSH specific transport systems have been identified in membranes of various cell types of rat, mice and rabbit. The presence of a Na+-independent transport system of GSH is confirmed by the similar behaviour of GSH uptake time-courses when Na+ in extracellular uptake medium was replaced with choline+ or K+ as well as by kinetic saturation and by the trans-stimulation effect on GSH uptake in GSH preloaded cells. Moreover, this transporter is activated when cations are present in extracellular medium and it is affected by membrane potential changes with an increase in GSH uptake values when membrane depolarization occurs. The present results also show a remarkable affinity and specificity of this transporter for GSH; in fact, Km value is very low (90 +/- 20 microM) and only compounds strictly related to GSH structure, such as GSH S-conjugates and GSH-ethyl ester, inhibit GSH uptake in 1407 cells. Finally, a possible hormonal control and modulation by the thiol-disulfide status of GSH transporter activity is suggested. PMID:9408181

Iantomasi, T; Favilli, F; Marraccini, P; Magaldi, T; Bruni, P; Vincenzini, M T

1997-12-01

86

Human intestinal fatty acid binding protein: report of an assay with studies in normal volunteers and intestinal ischemia.  

UK PubMed Central (United Kingdom)

BACKGROUND: Human intestinal fatty acid binding protein (hIFABP) is a cytoplasmic protein of mature small intestinal epithelium. Work with the rat demonstrated that serum levels of IFABP correlated with early phases of intestinal mucosal injury. The aim of this study was to develop an assay for hIFABP and assess its usefulness as a marker for intestinal mucosal injury in human beings. METHODS: Recombinant hIFABP (r-hIFABP) was used to produce rabbit anti-hIFABP. Specificity and avidity of binding were tested with immunoprecipitation and Scatchard analysis. r-hIFABP was labeled with 125I, and a competitive assay was developed. Urine and serum from normal volunteers and from patients with necrotizing enterocolitis (NEC), acute thromboembolic related intestinal ischemia, and systemic inflammatory response syndrome were tested for hIFABP. RESULTS: Molecular weight was 10(-12) kd, limit of detection was 1.87 ng/ml, and no cross-reactivity occurred when tested against rat IFABP or human heart FABP. Mean levels of hIFABP (ng/ml) were controls (serum less than 1.87, urine less than 1.87), NEC (serum 14.7 ng/ml), intestinal ischemia (serum 50 ng/ml, urine 52.3 ng/ml), systemic inflammatory response syndrome (serum 5.3 ng/ml, urine 13.2 ng/ml). CONCLUSIONS: This assay is quantitative for hIFABP in serum and urine. Results from both normal persons and those with various causes of intestinal ischemia parallel our previous findings in the rat. Preliminary findings suggest that hIFABP may serve as a diagnostic marker for early intestinal mucosal compromise and, in addition, that it should prove useful as a tool in developing rationale therapeutic regimens to treat these complex clinical problems.

Lieberman JM; Sacchettini J; Marks C; Marks WH

1997-03-01

87

[Primary small intestinal lymphoma: epidemiological, histological and therapeutic transition in Tunisia].  

UK PubMed Central (United Kingdom)

INTRODUCTION: Primary small intestinal lymphoma (PSIL) is the second Non-Hodgkin lymphoma (NHL) of the digestive tract (after gastric NHL). PURPOSE: To evaluate during the past 28 years the epidemiological, anatomoclinical and therapeutic changes of PSIL in Tunisia through an acquired experience of more than a quarter of a century. METHODS: Our retrospective study included patients with histologically confirmed small intestinal lymphoma from 1981 to 2008 in Tunisia at Salah Azaiz Institute. The cohort of 210 patients was divided into two groups: A group from 1981 to 1992 (152 patients) and B group from 1993 to 2008 (58 patients). We analysed the epidemiological, anatomoclinical, histological, and therapeutic characteristics. RESULTS: We observed a significant decrease in the annual incidence of PSIL but also a significant transition of diffuse immunoproliferative small intestinal disease (IPSID) also known as "Mediterranean" PSIL, which were progressively replaced by "Western" lymphomas. Laparotomy with or without a debulking surgery, largely performed in group A, has disappeared at the cost of a primary chemotherapy (p < 0.001). Five-year actuarial global and relapse free survivals were respectively 60.5 and 57.3%. CONCLUSION: PSIL in Tunisia were subjected to a triple transition: epidemiological, histological and therapeutic.

Belaid I; Mezlini A; Rais H; Jaafoura MH; Boussen H; Rifi H; Ayadi M; Chraiet N; Daoud N; El Benna H; Ayed FB

2012-04-01

88

The scintigraphic determination of small intestinal transit time in patients with irritable bowel syndrome  

International Nuclear Information System (INIS)

Diffuse disturbance in gastrointestinal motility may be present in patients with irritable bowel syndrome (IBS). To further investigate small intestinal motility in IBS patients small intestinal transit time (SITT) was determined and related to the symptom status. 11 female patients with IBS (mean age 29 years) were divided into those whose predominate symptom was diarrhea (N=6), and those with only constipation (N=5). All subjects ingested an isosmotic solution of lactulose (10 gm in 150cc of water) labeled with 99m-Tc-DTPA (Sn). The patient was studied supine under a 25 inch gamma camera with data collected at 1 frame per minute for 180 minutes or until activity appeared in the ascending colon. Regions of interest were selected over the cecum and ascending colon. The time of first appearance of radioactivity in the region of the cecum was taken as the small intestinal transit time. SITT in the 5 normal females was 98.7 +- 13 min (mean +- SEM). SITT in the IBS patients with diarrhea, 67.3 +- 7 min was significantly faster (p

1984-01-01

89

Chinese human smuggling in transit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Kleinschalige mensensmokkelaars beheersen de gehele smokkelroute van China naar de eindbestemming, grootschalige smokkelaars beheersen paradoxaal genoeg slechts een gedeelte van het traject. Dat is een van de conclusies uit de dissertatie “Chinese Smuggling in Transit” van Melvin Soudijn. Het beschr...

Soudijn, Melvin Roan Jasper

90

Effects of casoxin 4 on morphine inhibition of small animal intestinal contractility and gut transit in the mouse  

Directory of Open Access Journals (Sweden)

Full Text Available Glen S Patten1,2, Richard J Head1, Mahinda Y Abeywardena1,21CSIRO Preventative Health National Research Flagship, Adelaide, Australia; 2CSIRO Food and Nutritional Sciences, Adelaide, AustraliaBackground and aims: Chronic opioid analgesia has the debilitating side-effect of constipation in human patients. The major aims of this study were to: 1) characterize the opioid-specific antagonism of morphine-induced inhibition of electrically driven contraction of the small intestine of mice, rats, and guinea pigs; and 2) test if the oral delivery of small milk-derived opioid antagonist peptides could block morphine-induced inhibition of intestinal transit in mice.Methods: Mouse, rat, and guinea pig intact ileal sections were electrically stimulated to contract and inhibited with morphine in vitro. Morphine inhibition was then blocked by opioid subtype antagonists in the mouse and guinea pig. Using a polymeric dye, Poly R-478, the opioid antagonists casoxin 4 and lactoferroxin A were tested orally for blocking activity of morphine inhibition of gut transit in vivo by single or double gavage techniques.Results: The guinea pig tissue was more sensitive to morphine inhibition compared with the mouse or the rat (IC50 [half maximal inhibitory concentration] values as nmol/L ± SEM were 34 ± 3, 230 ± 13, and 310 ± 14 respectively) (P < 0.01). The inhibitory influence of opioid agonists (IC50) in electrically driven ileal mouse preparations were DADLE ([D-Ala2, D-Leu5]-enkephalin) ? met-enkephalin ? dynorphin A ? DAMGO ([D-Ala2, N-Me-Phe4, Gly-ol5]-enkephalin) > morphine > morphiceptin as nmol/L 13.9, 17.3, 19.5, 23.3, 230, and 403 respectively. The mouse demonstrated predominantly ?- and ?-opioid receptor activity with a smaller µ-opioid receptor component. Both mouse and guinea pig tissue were sensitive to casoxin 4 antagonism of morphine inhibition of contraction. In contrast to naloxone, relatively high oral doses of the µ-opioid receptor antagonists, casoxin 4 and lactoferroxin A, applied before and after morphine injection were unable to antagonize morphine inhibition of gut transit.Conclusions: Casoxin 4 reverses morphine-induced inhibition of contraction in mice and guinea pigs in vitro but fails to influence morphine inhibition of mouse small intestinal transit by the oral route.Keywords: lactoferroxin A, µ-opioid receptor antagonist, opioid agonists

Glen S Patten; Richard J Head; Mahinda Y Abeywardena

2011-01-01

91

Ischemic postconditioning attenuate reperfusion injury of small intestine: impact of mitochondrial permeability transition.  

UK PubMed Central (United Kingdom)

BACKGROUND: Ischemic postconditioning (IPoC) modulates the reperfusion maneuver to mitigate ischemia-reperfusion (I/R) injury. This study aims to investigate the effects and protective mechanism of IPoC on intestinal I/R injury. METHODS: Intestinal I/R was induced by occluding the superior mesenteric artery for 30 min followed by reperfusion for 60 min on male Wistar rats. IPoC was elicited by three cycles of 30-sec reperfusion and reocclusion of superior mesenteric artery at the initiation of reperfusion. Carboxyatractyloside (CATR), a mitochondrial permeability transition pore (mPTP) opener, and N-methyl-4-isoleucine cyclosporine (NIM811), an mPTP inhibitor, were administered separately in selected groups. The serum and intestinal sections were collected for analysis. RESULTS: IPoC and the administration of NIM811 significantly diminished the expression of intestinal-type fatty acid-binding protein and lactate dehydrogenase (3427±236.8 U/L for I/R, 1190.5±36.7 U/L for IPoC, 1399.3±295.6 U/L for I/R+NIM811, and 2002±370.9 IU/L for IPoC+CATR) in portal blood, the release of cytosolic cytochrome c, and the cleaved caspase 9 expression in intestinal mucosa after intestinal I/R injury (P<0.05). Histopathologically, IPoC and NIM811 mitigated mucosal damage after I/R as well (Chiu's score, 3.8±0.4 for I/R, 0.2±0.2 for IPoC, 0.4±0.2 for I/R+NIM811, and 4.2±0.2 for IPoC+CATR; apoptotic index, 59.5%±4.6% for I/R, 15.7%±15.7% for I/R+IPoC, 3.5%±3.5% for I/R+NIM811, and 67.1%±9.3% in IPoC+CATR). CATR negated the protection conferred by IPoC. CONCLUSIONS: IPoC and NIM811 attenuate intestinal I/R injury. The addition of CATR negated the effects of IPoC, indicating that the protective mechanism of IPoC was associated with the modulation of mPTP opening.

Cheng CH; Lin HC; Lai IR; Lai HS

2013-02-01

92

Sildenafil delays the intestinal transit of a liquid meal in awake rats  

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Full Text Available Sildenafil slows down the gastric emptying of a liquid test meal in awake rats and inhibits the contractility of intestinal tissue strips. We studied the acute effects of sildenafil on in vivo intestinal transit in rats. Fasted, male albino rats (180-220 g, N = 44) were treated (0.2 mL, iv) with sildenafil (4 mg/kg) or vehicle (0.01 N HCl). Ten minutes later they were fed a liquid test meal (99m technetium-labeled saline) injected directly into the duodenum. Twenty, 30 or 40 min after feeding, the rats were killed and transit throughout the gastrointestinal tract was evaluated by progression of the radiotracer using the geometric center method. The effect of sildenafil on mean arterial pressure (MAP) was monitored in a separate group of rats (N = 14). Data (medians within interquartile ranges) were compared by the Mann-Whitney U-test. The location of the geometric center was significantly more distal in vehicle-treated than in sildenafil-treated rats at 20, 30, and 40 min after test meal instillation (3.3 (3.0-3.6) vs 2.9 (2.7-3.1); 3.8 (3.4-4.0) vs 2.9 (2.5-3.1), and 4.3 (3.9-4.5) vs 3.4 (3.2-3.7), respectively; P < 0.05). MAP was unchanged in vehicle-treated rats but decreased by 25% (P < 0.05) within 10 min after sildenafil injection. In conclusion, besides transiently decreasing MAP, sildenafil delays the intestinal transit of a liquid test meal in awake rats.

J.R.V Graça; G.M Macedo; R.C Palheta Jr; F. de A.A Gondim; R.O Nogueira; J.M Correia; F.H Rola; R.B Oliveira; M.A.N Souza; A.A Santos

2008-01-01

93

Tracking the cell hierarchy in the human intestine using biochemical signatures derived by mid-infrared microspectroscopy.  

Science.gov (United States)

Markers of gastrointestinal (GI) stem cells remain elusive. We employed synchrotron Fourier-transform infrared (FTIR) microspectroscopy to derive mid-infrared (IR) spectra along the length of human GI crypts. Tissue sections (10-?m thick) were floated onto BaF2 windows and image maps were acquired of small intestine and large bowel crypts in transmission mode with an aperture of ?10 ?m×10 ?m. Counting upwards in a step-size (?10 ?m) fashion from the crypt base, IR spectra were extracted from the image maps and each spectrum corresponding to a particular location was identified. Spectra were analyzed using principal component analysis plus linear discriminant analysis. Compared to putative crypt base columnar/Paneth cells, those assigned as label-retaining cells were chemically more similar to putative large bowel stem cells and, the small intestine transit-amplifying cells were closest to large bowel transit-amplifying cells; interestingly, the base of small intestine crypts was the most chemically-distinct. This study suggests that in the complex cell lineage of human GI crypts, chemical similarities as revealed by FTIR microspectroscopy between regions putatively assigned as stem cell, transit-amplifying and terminally-differentiated facilitates identification of cell function. PMID:19393589

Walsh, Michael J; Hammiche, Azzedine; Fellous, Tariq G; Nicholson, James M; Cotte, Marine; Susini, Jean; Fullwood, Nigel J; Martin-Hirsch, Pierre L; Alison, Malcolm R; Martin, Francis L

2009-02-21

94

Tracking the cell hierarchy in the human intestine using biochemical signatures derived by mid-infrared microspectroscopy.  

UK PubMed Central (United Kingdom)

Markers of gastrointestinal (GI) stem cells remain elusive. We employed synchrotron Fourier-transform infrared (FTIR) microspectroscopy to derive mid-infrared (IR) spectra along the length of human GI crypts. Tissue sections (10-?m thick) were floated onto BaF2 windows and image maps were acquired of small intestine and large bowel crypts in transmission mode with an aperture of ?10 ?m×10 ?m. Counting upwards in a step-size (?10 ?m) fashion from the crypt base, IR spectra were extracted from the image maps and each spectrum corresponding to a particular location was identified. Spectra were analyzed using principal component analysis plus linear discriminant analysis. Compared to putative crypt base columnar/Paneth cells, those assigned as label-retaining cells were chemically more similar to putative large bowel stem cells and, the small intestine transit-amplifying cells were closest to large bowel transit-amplifying cells; interestingly, the base of small intestine crypts was the most chemically-distinct. This study suggests that in the complex cell lineage of human GI crypts, chemical similarities as revealed by FTIR microspectroscopy between regions putatively assigned as stem cell, transit-amplifying and terminally-differentiated facilitates identification of cell function.

Walsh MJ; Hammiche A; Fellous TG; Nicholson JM; Cotte M; Susini J; Fullwood NJ; Martin-Hirsch PL; Alison MR; Martin FL

2009-07-01

95

Chicory inulin does not increase stool weight or speed up intestinal transit time in healthy male subjects.  

UK PubMed Central (United Kingdom)

Inulin is a non-digestible oligosaccharide classified as a prebiotic, a substrate that promotes the growth of certain beneficial microorganisms in the gut. We examined the effect of a 20 g day(-1) supplement of chicory inulin on stool weight, intestinal transit time, stool frequency and consistency, selected intestinal microorganisms and enzymes, fecal pH, short chain fatty acids and ammonia produced as by-products of bacterial fermentation. Twelve healthy male volunteers consumed a well-defined, controlled diet with and without a 20 g day(-1) supplement of chicory inulin (degree of polymerization (DP) ranging for 2-60), with each treatment lasting for 3 weeks in a randomized, double-blind crossover trial. Inulin was consumed in a low fat ice cream. No differences were found in flavor or appeal between the control and inulin-containing ice creams. Inulin consumption resulted in a significant increase in total anaerobes and Lactobacillus species and a significant decrease in ammonia levels and ?-glucuronidase activity. Flatulence increased significantly with the inulin treatment. No other significant differences were found in bowel function with the addition of inulin to the diet. Thus, inulin is easily incorporated into a food product and has no negative effects on food acceptability. Twenty grams of inulin was well tolerated, but had minimal effects on measures of laxation in healthy, human subjects.

Slavin J; Feirtag J

2011-01-01

96

Culture of human intestinal epithelial cell using the dissociating enzyme thermolysin and endothelin-3  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Epithelium, a highly dynamic system, plays a key role in the homeostasis of the intestine. However, thus far a human intestinal epithelial cell line has not been established in many countries. Fetal tissue was selected to generate viable cell cultures for its sterile condition, effective generation, and differentiated character. The purpose of the present study was to culture human intestinal epithelial cells by a relatively simple method. Thermolysin was added to improve (more) the yield of epithelial cells, while endothelin-3 was added to stimulate their growth. By adding endothelin-3, the achievement ratio (viable cell cultures/total cultures) was enhanced to 60% of a total of 10 cultures (initiated from 8 distinct fetal small intestines), allowing the generation of viable epithelial cell cultures. Western blot, real-time PCR and immunofluorescent staining showed that cytokeratins 8, 18 and mouse intestinal mucosa-1/39 had high expression levels in human intestinal epithelial cells. Differentiated markers such as sucrase-isomaltase, aminopeptidase N and dipeptidylpeptidase IV also showed high expression levels in human intestinal epithelial cells. Differentiated human intestinal epithelial cells, with the expression of surface markers (cytokeratins 8, 18 and mouse intestinal mucosa-1/39) and secretion of cytokines (sucrase-isomaltase, aminopeptidase N and dipeptidylpeptidase IV), may be cultured by the thermolysin and endothelin-3 method and maintained for at least 20 passages. This is relatively simple, requiring no sophisticated techniques or instruments, and may have a number of varied applications.

Liu, Z.; Zhang, P.; Zhou, Y.; Qin, H.; Shen, T.

2010-05-01

97

Culture of human intestinal epithelial cell using the dissociating enzyme thermolysin and endothelin-3  

Directory of Open Access Journals (Sweden)

Full Text Available Epithelium, a highly dynamic system, plays a key role in the homeostasis of the intestine. However, thus far a human intestinal epithelial cell line has not been established in many countries. Fetal tissue was selected to generate viable cell cultures for its sterile condition, effective generation, and differentiated character. The purpose of the present study was to culture human intestinal epithelial cells by a relatively simple method. Thermolysin was added to improve the yield of epithelial cells, while endothelin-3 was added to stimulate their growth. By adding endothelin-3, the achievement ratio (viable cell cultures/total cultures) was enhanced to 60% of a total of 10 cultures (initiated from 8 distinct fetal small intestines), allowing the generation of viable epithelial cell cultures. Western blot, real-time PCR and immunofluorescent staining showed that cytokeratins 8, 18 and mouse intestinal mucosa-1/39 had high expression levels in human intestinal epithelial cells. Differentiated markers such as sucrase-isomaltase, aminopeptidase N and dipeptidylpeptidase IV also showed high expression levels in human intestinal epithelial cells. Differentiated human intestinal epithelial cells, with the expression of surface markers (cytokeratins 8, 18 and mouse intestinal mucosa-1/39) and secretion of cytokines (sucrase-isomaltase, aminopeptidase N and dipeptidylpeptidase IV), may be cultured by the thermolysin and endothelin-3 method and maintained for at least 20 passages. This is relatively simple, requiring no sophisticated techniques or instruments, and may have a number of varied applications.

Z. Liu; P. Zhang; Y. Zhou; H. Qin; T. Shen

2010-01-01

98

Effects of liquid versus solid diet on colonic transit in humans. Evaluation by standard colonic transit scintigraphy  

International Nuclear Information System (INIS)

The effects of liquid versus solid diet on human colonic transit were investigated, and transit following cecal instillation of tracer was compared with transit following instillation in the proximal jejunum. In a randomized cross-over, single-blind fashion, 6 normal volunteers ingesting either normal solid foods or a liquid diet were studied using colonic transit scintigraphy. 111In-DTPA was instilled either into the cecum via a long intestinal tube or into the proximal jejunum via a feeding tube. Compared with the liquid diet, the solid diet slowed transit in the cecum and ascending colon (p less than 0.025) and delayed progression of the geometric center (p less than 0.05) during the first 4 h of the study. Transit from 18 to 48 h was similar on the 2 diets. On the solid diet, transit was similar whether 111In-DTPA was instilled into the proximal jejunum or into the cecum. Transit from the terminal ileum to the cecum was assessed in an additional 5 volunteers following jejunal instillation of 99mTc-DTPA. Cecal filling was rapid (T1/2 = 0.49 h) and complete in all subjects before the onset of cecal emptying. These results suggest that colonic transit is slower on a solid than a liquid diet and that jejunal instillation of radiopharmaceuticals should be suitable for colonic transit studies in most subjects.

1990-01-01

99

Adhesion and absorption of Tc-99 labelled tracers for estimating the intestinal transit  

International Nuclear Information System (INIS)

Liquid, semisolid and solid markers are used to calculate esophageal transit, gastric emptying or intestinal transit. The purpose of this study was to prove in vivo stability and wall absorption. 41 Wistar rats were fed with sup(99m)Tc-DTPA (n=11), sup(99m)Tc-labeled chicken liver (n=11), sup(99m)Tc-Chelex (n=11) or sup(99m)Tc-pertechnetate (n=8). One to three hours later the animals were killed, the gut was dissected and rinsed with water. The water for rinsing, the activity of the intestinal wall and other organs were measured in a whole body counter. The calculated fractions (%) of intraluminal (1), wall-absorbed (W) and extraintestianl (E) activity in relation to total counts were: DPTA: (1) 89 +- 3.2, (W) 8 +- 2.1, (E) 2.3 +- 1.6. CHELEX: (1) 98.8 +- 0.6, (W) 0.9 +-0.4, (E) 0.3 +- 0.4. CHICKEN LIVER: (1) 96.9 +- 1.3, (W) 2.3 +- 1.1, (E) 0.8 +- 0.8. PERTECHNETATE: (1) 36.4 +- 12, (W) 9.5 +- 2.7, (E) 54.2 +- 13. The differences were significant between all groups (p

1986-01-01

100

Sildenafil delays the intestinal transit of a liquid meal in awake rats  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Sildenafil slows down the gastric emptying of a liquid test meal in awake rats and inhibits the contractility of intestinal tissue strips. We studied the acute effects of sildenafil on in vivo intestinal transit in rats. Fasted, male albino rats (180-220 g, N = 44) were treated (0.2 mL, iv) with sildenafil (4 mg/kg) or vehicle (0.01 N HCl). Ten minutes later they were fed a liquid test meal (99m technetium-labeled saline) injected directly into the duodenum. Twenty, 30 or (more) 40 min after feeding, the rats were killed and transit throughout the gastrointestinal tract was evaluated by progression of the radiotracer using the geometric center method. The effect of sildenafil on mean arterial pressure (MAP) was monitored in a separate group of rats (N = 14). Data (medians within interquartile ranges) were compared by the Mann-Whitney U-test. The location of the geometric center was significantly more distal in vehicle-treated than in sildenafil-treated rats at 20, 30, and 40 min after test meal instillation (3.3 (3.0-3.6) vs 2.9 (2.7-3.1); 3.8 (3.4-4.0) vs 2.9 (2.5-3.1), and 4.3 (3.9-4.5) vs 3.4 (3.2-3.7), respectively; P

Graça, J.R.V; Macedo, G.M; Palheta Jr, R.C; Gondim, F. de A.A; Nogueira, R.O; Correia, J.M; Rola, F.H; Oliveira, R.B; Souza, M.A.N; Santos, A.A

2008-01-01

 
 
 
 
101

The scintigraphic determination of small intestinal transit time in patients with irritable bowel syndrome  

Energy Technology Data Exchange (ETDEWEB)

Diffuse disturbance in gastrointestinal motility may be present in patients with irritable bowel syndrome (IBS). To further investigate small intestinal motility in IBS patients small intestinal transit time (SITT) was determined and related to the symptom status. 11 female patients with IBS (mean age 29 years) were divided into those whose predominate symptom was diarrhea (N=6), and those with only constipation (N=5). All subjects ingested an isosmotic solution of lactulose (10 gm in 150cc of water) labeled with 99m-Tc-DTPA (Sn). The patient was studied supine under a 25 inch gamma camera with data collected at 1 frame per minute for 180 minutes or until activity appeared in the ascending colon. Regions of interest were selected over the cecum and ascending colon. The time of first appearance of radioactivity in the region of the cecum was taken as the small intestinal transit time. SITT in the 5 normal females was 98.7 +- 13 min (mean +- SEM). SITT in the IBS patients with diarrhea, 67.3 +- 7 min was significantly faster (p< 0.08). SITT in the constipated IBS patients, 126 +- 12 min, was slower than normals and significantly different from diarrhea patients (p< 0.001). These studies show that IBS patients with diarrhea have significantly faster SITT than normals while constipated IBS patients have significantly slower SITT than the diarrhea subgroup. Further, this study emphasizes the need to study the various symptomatic subgroups of IBs patients independently and indicates a possible role for abnormal SITT in the pathogenesis of IBS.

Marano, A.R.; Caride, V.J.; Shah, R.V.; Prokop, E.K.; Troncale, F.J.; McCallum, R.W.

1984-01-01

102

Quantitative prediction of intestinal metabolism in humans from a simplified intestinal availability model and empirical scaling factor.  

Science.gov (United States)

This study aimed to establish a practical and convenient method of predicting intestinal availability (F(g)) in humans for highly permeable compounds at the drug discovery stage, with a focus on CYP3A4-mediated metabolism. We constructed a "simplified F(g) model," described using only metabolic parameters, assuming that passive diffusion is dominant when permeability is high and that the effect of transporters in epithelial cells is negligible. Five substrates for CYP3A4 (alprazolam, amlodipine, clonazepam, midazolam, and nifedipine) and four for both CYP3A4 and P-glycoprotein (P-gp) (nicardipine, quinidine, tacrolimus, and verapamil) were used as model compounds. Observed fraction of drug absorbed (F(a)F(g)) values for these compounds were calculated from in vivo pharmacokinetic (PK) parameters, whereas in vitro intestinal intrinsic clearance (CL(int,intestine)) was determined using human intestinal microsomes. The CL(int,intestine) for the model compounds corrected with that of midazolam was defined as CL(m,index) and incorporated into a simplified F(g) model with empirical scaling factor. Regardless of whether the compound was a P-gp substrate, the F(a)F(g) could be reasonably fitted by the simplified F(g) model, and the value of the empirical scaling factor was well estimated. These results suggest that the effects of P-gp on F(a) and F(g) are substantially minor, at least in the case of highly permeable compounds. Furthermore, liver intrinsic clearance (CL(int,liver)) can be used as a surrogate index of intestinal metabolism based on the relationship between CL(int,liver) and CL(m,index). F(g) can be easily predicted using a simplified F(g) model with the empirical scaling factor, enabling more confident selection of drug candidates with desirable PK profiles in humans. PMID:20354105

Kadono, Keitaro; Akabane, Takafumi; Tabata, Kenji; Gato, Katsuhiko; Terashita, Shigeyuki; Teramura, Toshio

2010-03-30

103

Human primary intestinal epithelial cells as an improved in vitro model for Cryptosporidium parvum infection.  

UK PubMed Central (United Kingdom)

The study of human intestinal pathogens has been limited by the lack of methods for the long-term culture of primary human intestinal epithelial cells (PECs). The development of infection models with PECs would allow a better understanding of host-parasite interactions. The objective of this study was to develop a novel method for prolonged in vitro cultivation of PECs that can be used to study Cryptosporidium infection. We isolated intact crypts from human intestines removed during weight loss surgery. The fragments of intestinal layers were cultivated with culture medium supplemented with growth factors and antiapoptotic molecules. After 7 days, the PECs formed self-regenerating cell clusters, forming villi that resemble intestinal epithelium. The PECs proliferated and remained viable for at least 60 days. The cells expressed markers for intestinal stem cells, epithelial cells, and mature enterocytes. The PECs were infected with Cryptosporidium. In contrast to older models in which parasite numbers decay, the burden of parasites increased for >120 h. In summary, we describe here a novel method for the cultivation of self-regenerating human epithelial cells from small intestinal crypts, which contain both intestinal stem cells and mature villus cells. We present data that suggest these cells support Cryptosporidium better than existing cell lines. PECs should provide an improved tool for studying host-parasite interactions involving Cryptosporidium and other intestinal pathogens.

Castellanos-Gonzalez A; Cabada MM; Nichols J; Gomez G; White AC Jr

2013-06-01

104

Cdx2 modulates proliferation in normal human intestinal epithelial crypt cells  

International Nuclear Information System (INIS)

The homeobox gene Cdx2 is involved in the regulation of the expression of intestine specific markers such as sucrase-isomaltase and lactase-phlorizin hydrolase. Previous studies performed with immortalized or transformed intestinal cell lines have provided evidence that Cdx2 can promote morphological and functional differentiation in these experimental models. However, no data exist concerning the implication of this factor in normal human intestinal cell physiology. In the present work, we have investigated the role of Cdx2 in normal human intestinal epithelial crypt (HIEC) cells that lack this transcription factor. The establishment of HIEC cells expressing Cdx2 in an inducible manner shows that forced expression of Cdx2 significantly alters the proliferation of intestinal crypt cells and stimulates dipeptidylpeptidase IV expression but is not sufficient to trigger intestinal terminal differentiation. These observations suggest that Cdx2 requires additional factors to activate the enterocyte differentiation program in normal undifferentiated cells.

2006-03-31

105

EFFECTS OF AQUEOUS EXTRACTS OF HIBISCUS SABDARIFFA CALYCES AND OCIMUM GRATISSIMUM LEAVES ON INTESTINAL TRANSIT IN RATS  

Directory of Open Access Journals (Sweden)

Full Text Available The effects of aqueous extracts of the leaves of Ocimum gratissimum and calyces of Hibiscus sabdariffa on intestinal transit were determined in experimental rats The leaves of Ocimum gratissimum were oven dried and then pulverized. The dried calyces of Hibiscus sabdariffa were also pulverized. 10% extracts of both powders were made and administered orally to rats at varying doses. Test rats were given the 10% extracts of Ocimum gratissimum and Hibiscus sabdariffa at 0.5/100g, 1ml/100g, 2ml/100g body weight. Control rats received saline instead of extracts. After 30 minutes, each animal was then given 1.5 ml of a dye solution orally. 1 hour after administering the dye each rat was sacrificed and the intestine carefully dissected out. The length of the intestine and the transit point of the orally administered dye were then measured. The transit point was calculated as a percentage of the total length of the intestine. The extracts of both Ocimum gratissimum and Hibiscus sabdariffa caused a reduction in the transit points of the dye. The extract of Hibiscus sabdariffa was more effective. The reduction in transit point, and hence the increase in transit time by both extracts indicates that the plants could be useful at appropriate doses in the control of diarrhea. Hibiscus sabdariffa would be more effective in this regard.

OWULADE M. O

2004-01-01

106

Linaclotide, through activation of guanylate cyclase C, acts locally in the gastrointestinal tract to elicit enhanced intestinal secretion and transit.  

UK PubMed Central (United Kingdom)

Linaclotide is a first-in-class, orally administered 14-amino acid peptide that is in development for the treatment of irritable bowel syndrome with constipation and chronic constipation. We have characterized the solution structure of linaclotide, the in vitro binding and agonist activity to guanylate cyclase C receptors, the stability of linaclotide under conditions mimicking the gastric environment, oral bioavailability, and the pharmacodynamic effects in rat models of gastrointestinal transit and intestinal secretion. Nuclear magnetic resonance spectroscopy analysis determined that the molecular structure of linaclotide is stabilized by three intramolecular disulfide bridges. Linaclotide exhibited high affinity and pH-independent binding (K(i): 1.23-1.64 nM) to guanylate cyclase C receptors on human colon carcinoma T84 cells and concomitantly, linaclotide binding resulted in a significant, concentration-dependent accumulation of intracellular cyclic guanosine-3', 5'-monophosphate (cGMP) (EC??:99 nM). Linaclotide was stable after 3 h incubation in simulated gastric fluid (pH 1) and similarly, was completely resistant to hydrolysis by pepsin. Pharmacokinetic analysis of linaclotide showed very low oral bioavailability (0.1%). Orally administered linaclotide elicited a significant, dose-dependent increase in gastrointestinal transit rates in rats at doses of ?5 ?g/kg. Exposure of surgically ligated small intestinal loops to linaclotide induced a significant increase in fluid secretion, accompanied by a significant increase in intraluminal cGMP levels. These results suggest that the guanylate cyclase C agonist linaclotide elicits potent pharmacological responses locally in the gastrointestinal tract, and that orally administered guanylate cyclase C agonists may be capable of improving bowel habits in patients suffering from irritable bowel syndrome with constipation and chronic constipation.

Busby RW; Bryant AP; Bartolini WP; Cordero EA; Hannig G; Kessler MM; Mahajan-Miklos S; Pierce CM; Solinga RM; Sun LJ; Tobin JV; Kurtz CB; Currie MG

2010-12-01

107

Linaclotide, through activation of guanylate cyclase C, acts locally in the gastrointestinal tract to elicit enhanced intestinal secretion and transit.  

Science.gov (United States)

Linaclotide is a first-in-class, orally administered 14-amino acid peptide that is in development for the treatment of irritable bowel syndrome with constipation and chronic constipation. We have characterized the solution structure of linaclotide, the in vitro binding and agonist activity to guanylate cyclase C receptors, the stability of linaclotide under conditions mimicking the gastric environment, oral bioavailability, and the pharmacodynamic effects in rat models of gastrointestinal transit and intestinal secretion. Nuclear magnetic resonance spectroscopy analysis determined that the molecular structure of linaclotide is stabilized by three intramolecular disulfide bridges. Linaclotide exhibited high affinity and pH-independent binding (K(i): 1.23-1.64 nM) to guanylate cyclase C receptors on human colon carcinoma T84 cells and concomitantly, linaclotide binding resulted in a significant, concentration-dependent accumulation of intracellular cyclic guanosine-3', 5'-monophosphate (cGMP) (EC??:99 nM). Linaclotide was stable after 3 h incubation in simulated gastric fluid (pH 1) and similarly, was completely resistant to hydrolysis by pepsin. Pharmacokinetic analysis of linaclotide showed very low oral bioavailability (0.1%). Orally administered linaclotide elicited a significant, dose-dependent increase in gastrointestinal transit rates in rats at doses of ?5 ?g/kg. Exposure of surgically ligated small intestinal loops to linaclotide induced a significant increase in fluid secretion, accompanied by a significant increase in intraluminal cGMP levels. These results suggest that the guanylate cyclase C agonist linaclotide elicits potent pharmacological responses locally in the gastrointestinal tract, and that orally administered guanylate cyclase C agonists may be capable of improving bowel habits in patients suffering from irritable bowel syndrome with constipation and chronic constipation. PMID:20863829

Busby, Robert W; Bryant, Alexander P; Bartolini, Wilmin P; Cordero, Etchell A; Hannig, Gerhard; Kessler, Marco M; Mahajan-Miklos, Shalina; Pierce, Christine M; Solinga, Robert M; Sun, Li Jing; Tobin, Jenny V; Kurtz, Caroline B; Currie, Mark G

2010-09-20

108

Age-related human small intestine methylation: evidence for stem cell niches  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The small intestine is constructed of many crypts and villi, and mouse studies suggest that each crypt contains multiple stem cells. Very little is known about human small intestines because mouse fate mapping strategies are impractical in humans. However, it is theoretically possible that stem cell histories are inherently written within their genomes. Genomes appear to record histories (as exemplified by use of molecular clocks), and therefore it may be possible to reconstruct somatic cell dynamics from somatic cell errors. Recent human colon studies suggest that random somatic epigenetic errors record stem cell histories (ancestry and total numbers of divisions). Potentially age-related methylation also occurs in human small intestines, which would allow characterization of their stem cells and comparisons with the colon. Methods Methylation patterns in individual crypts from 13 small intestines (17 to 78 years old) were measured by bisulfite sequencing. The methylation patterns were analyzed by a quantitative model to distinguish between immortal or niche stem cell lineages. Results Age-related methylation was observed in the human small intestines. Crypt methylation patterns were more consistent with stem cell niches than immortal stem cell lineages. Human large and small intestine crypt niches appeared to have similar stem cell dynamics, but relatively less methylation accumulated with age in the small intestines. There were no apparent stem cell differences between the duodenum and ileum, and stem cell survival did not appear to decline with aging. Conclusion Crypt niches containing multiple stem cells appear to maintain human small intestines. Crypt niches appear similar in the colon and small intestine, and the small intestinal stem cell mitotic rate is the same as or perhaps slower than that of the colon. Although further studies are needed, age-related methylation appears to record somatic cell histories, and a somatic epigenetic molecular clock strategy may potentially be applied to other human tissues to reconstruct otherwise occult stem cell histories.

Kim Jung; Siegmund Kimberly D; Tavaré Simon; Shibata Darryl

2005-01-01

109

Directed differentiation of human pluripotent stem cells into intestinal tissue in vitro.  

Science.gov (United States)

Studies in embryonic development have guided successful efforts to direct the differentiation of human embryonic and induced pluripotent stem cells (PSCs) into specific organ cell types in vitro. For example, human PSCs have been differentiated into monolayer cultures of liver hepatocytes and pancreatic endocrine cells that have therapeutic efficacy in animal models of liver disease and diabetes, respectively. However, the generation of complex three-dimensional organ tissues in vitro remains a major challenge for translational studies. Here we establish a robust and efficient process to direct the differentiation of human PSCs into intestinal tissue in vitro using a temporal series of growth factor manipulations to mimic embryonic intestinal development. This involved activin-induced definitive endoderm formation, FGF/Wnt-induced posterior endoderm pattering, hindgut specification and morphogenesis, and a pro-intestinal culture system to promote intestinal growth, morphogenesis and cytodifferentiation. The resulting three-dimensional intestinal 'organoids' consisted of a polarized, columnar epithelium that was patterned into villus-like structures and crypt-like proliferative zones that expressed intestinal stem cell markers. The epithelium contained functional enterocytes, as well as goblet, Paneth and enteroendocrine cells. Using this culture system as a model to study human intestinal development, we identified that the combined activity of WNT3A and FGF4 is required for hindgut specification whereas FGF4 alone is sufficient to promote hindgut morphogenesis. Our data indicate that human intestinal stem cells form de novo during development. We also determined that NEUROG3, a pro-endocrine transcription factor that is mutated in enteric anendocrinosis, is both necessary and sufficient for human enteroendocrine cell development in vitro. PSC-derived human intestinal tissue should allow for unprecedented studies of human intestinal development and disease. PMID:21151107

Spence, Jason R; Mayhew, Christopher N; Rankin, Scott A; Kuhar, Matthew F; Vallance, Jefferson E; Tolle, Kathryn; Hoskins, Elizabeth E; Kalinichenko, Vladimir V; Wells, Susanne I; Zorn, Aaron M; Shroyer, Noah F; Wells, James M

2010-12-12

110

Directed differentiation of human pluripotent stem cells into intestinal tissue in vitro.  

UK PubMed Central (United Kingdom)

Studies in embryonic development have guided successful efforts to direct the differentiation of human embryonic and induced pluripotent stem cells (PSCs) into specific organ cell types in vitro. For example, human PSCs have been differentiated into monolayer cultures of liver hepatocytes and pancreatic endocrine cells that have therapeutic efficacy in animal models of liver disease and diabetes, respectively. However, the generation of complex three-dimensional organ tissues in vitro remains a major challenge for translational studies. Here we establish a robust and efficient process to direct the differentiation of human PSCs into intestinal tissue in vitro using a temporal series of growth factor manipulations to mimic embryonic intestinal development. This involved activin-induced definitive endoderm formation, FGF/Wnt-induced posterior endoderm pattering, hindgut specification and morphogenesis, and a pro-intestinal culture system to promote intestinal growth, morphogenesis and cytodifferentiation. The resulting three-dimensional intestinal 'organoids' consisted of a polarized, columnar epithelium that was patterned into villus-like structures and crypt-like proliferative zones that expressed intestinal stem cell markers. The epithelium contained functional enterocytes, as well as goblet, Paneth and enteroendocrine cells. Using this culture system as a model to study human intestinal development, we identified that the combined activity of WNT3A and FGF4 is required for hindgut specification whereas FGF4 alone is sufficient to promote hindgut morphogenesis. Our data indicate that human intestinal stem cells form de novo during development. We also determined that NEUROG3, a pro-endocrine transcription factor that is mutated in enteric anendocrinosis, is both necessary and sufficient for human enteroendocrine cell development in vitro. PSC-derived human intestinal tissue should allow for unprecedented studies of human intestinal development and disease.

Spence JR; Mayhew CN; Rankin SA; Kuhar MF; Vallance JE; Tolle K; Hoskins EE; Kalinichenko VV; Wells SI; Zorn AM; Shroyer NF; Wells JM

2011-02-01

111

Structural and inhibition studies of human intestinal glucosidases.  

UK PubMed Central (United Kingdom)

Human maltase-glucoamylase (MGAM) and sucrase-isomaltase (SI) are the small-intestinal glucosidases responsible for catalyzing the last glucose-releasing step in starch digestion. MGAM and SI are each composed of duplicated catalytic domains, N- and C-terminal, which display complementary substrate specificities for the mixture of short linear and branch oligosaccharide substrates that typically make up terminal starch digestion products. As MGAM and SI are involved in post-prandial glucose production, regulating their activities with ?-glucosidase inhibitors is an attractive approach to controlling blood glucose levels for the prevention and treatment of Type 2 diabetes. To better understand the complementary activities and mechanism of inhibition of these intestinal glucosidases, this thesis aims to characterize the individual N- and C-terminal MGAM and SI domains using a combination of X-ray crystallographic structural studies, enzyme kinetics, and inhibitor studies. First, the structure of the N-terminal domain of MGAM (ntMGAM) was determined in its apo form and in complex with the inhibitor acarbose. In addition to sequence alignments and kinetics studies, the structures provide insight into the preference of the N-terminal MGAM domain for short linear substrates and the C-terminal domain for longer substrates. Second, the structure of ntMGAM was determined in complex with various ?-glucosidase inhibitors, including those currently on the market (acarbose and miglitol), a new class of inhibitors from natural extracts of Salacia reticulata (salacinol, kotalanol and de-O-sulfonated kotalanol) and chemically synthesized derivatives of salacinol. These studies reveal the features of the Salacia reticulata inhibitors that are essential for inhibitory activity and highlight their potential as future drug candidates. Third, the crystal structure of the N-terminal domain of SI (ntSI) was determined in apo-form and in complex with kotalanol. Structural comparison of ntSI and ntMGAM reveal key differences in active site architectures, which are proposed to confer differential substrate specificity.

Sim L

112

Effect of Ceftaroline on Normal Human Intestinal Microflora?  

Science.gov (United States)

Ceftaroline is a new broad-spectrum cephalosporin being developed for the treatment of serious bacterial infections, including those caused by aerobic Gram-positive and Gram-negative bacteria. The purpose of the present study was to investigate the effect of administration of ceftaroline on the intestinal flora of healthy subjects. Twelve healthy subjects (6 males and 6 females), 20 to 41 years of age, received ceftaroline (600 mg) by intravenous infusion every 12 h (q12h) for 7 days. Plasma and feces were collected for determination of ceftaroline concentration and analysis of fecal flora. Fecal specimens were cultured on nonselective and selective media. Different colony types were counted, isolated in pure culture, and identified to the genus level. All new strains of colonizing bacteria were tested for susceptibility to ceftaroline. The concentrations of ceftaroline in plasma were as follows: on day 2, 17.5 to 34.8 mg/liter; on day 5, 19.7 to 33.2 mg/liter; and on day 7, 18.0 to 29.8 mg/liter. No ceftaroline concentrations were found on day ?1, 9, 14, or 21. No measurable concentrations in feces were found on day ?1, 2, 5, 7, 9, 14, or 21. There was a minor impact on the numbers of Escherichia coli strains, while the numbers of enterococci and Candida albicans strains were not affected. There were moderate decreases in the numbers of bifidobacteria and lactobacilli during the first 7 days, while the numbers of clostridia increased during the same period. No impact on the numbers of Bacteroides bacteria was noticed. No new colonizing aerobic or anaerobic bacteria resistant to ceftaroline (MIC ? 4 mg/liter) were found. Ceftaroline had no significant ecological impact on the human intestinal microflora.

Panagiotidis, Georgios; Backstrom, Tobias; Asker-Hagelberg, Charlotte; Jandourek, Alena; Weintraub, Andrej; Nord, Carl Erik

2010-01-01

113

Cloning and expression of the human vasoactive intestinal peptide receptor  

Energy Technology Data Exchange (ETDEWEB)

Vasoactive intestinal peptide (VIP) is a neuroendocrine mediator found in the central and peripheral nervous systems. Distinct subsets of neural, respiratory, gastrointestinal, and immune cells bear specific high-affinity receptors for VIP, which are associated with a guanine nucleotide-binding (G) protein capable of activatingadenylate cyclase. A cDNA clone (GPRN1) encoding the human VIP receptor was identified in librares prepared from the Nalm 6 line of leukemic pre-B lymphoblasts and the HT-29 line of colon carcinoma cells. The deduced 362-amino acid polypeptide sequence encoded by GPRN1 shares a seven-transmembrane-segment hydropathicity profile with other G protein-coupled receptors. Northern blot analyses identified a 2.7-kilobase transcript of the VIP receptor in Nalm 6 and HT-29 cells as well as in tissues from rat brain, colon, heart, lung, kidney, spleen, and small intestine. COS-6 cells transfected with GPRN1 bound {sup 125}I-labeled VIP specifically with a dissociation constant (K{sub d}) of 2.5 nM. VIP--and less effectively secretin, peptide histidine isoleucine (PHI), and glucagon competitively displaced bound {sup 125}I-VIP from transfected COS-6 cells, with potencies in the order VIP > secretin = PHI >> glucagon. VIP stimulated adenylate cyclase activity in stably transfected Chinese hanster ovary K1 cells, indicing a 3-fold increase in the intracellular level of cAMP. The VIP receptor cloned exhibits {le}24% homology with other receptors in the same superfamily and thus represents a subset of G protein-coupled receptors for peptide ligands.

Sreedharan, S.P.; Robichon, A.; Peterson, K.E.; Goetzl, E.J. (Univ. of California Medical Center, San Francisco (United States))

1991-06-01

114

Degradation of neohesperidin dihydrochalcone by human intestinal bacteria.  

Science.gov (United States)

The degradation of neohesperidin dihydrochalcone by human intestinal microbiota was studied in vitro. Human fecal slurries converted neohesperidin dihydrochalcone anoxically to 3-(3-hydroxy-4-methoxyphenyl)propionic acid or 3-(3,4-dihydroxyphenyl)propionic acid. Two transient intermediates were identified as hesperetin dihydrochalcone 4'-beta-d-glucoside and hesperetin dihydrochalcone. These metabolites suggest that neohesperidin dihydrochalcone is first deglycosylated to hesperetin dihydrochalcone 4'-beta-d-glucoside and subsequently to the aglycon hesperetin dihydrochalcone. The latter is hydrolyzed to the corresponding 3-(3-hydroxy-4-methoxyphenyl)propionic acid and probably phloroglucinol. Eubacterium ramulus and Clostridium orbiscindens were not capable of converting neohesperidin dihydrochalcone. However, hesperetin dihydrochalcone 4'-beta-d-glucoside was converted by E. ramulus to hesperetin dihydrochalcone and further to 3-(3-hydroxy-4-methoxyphenyl)propionic acid, but not by C. orbiscindens. In contrast, hesperetin dihydrochalcone was cleaved to 3-(3-hydroxy-4-methoxyphenyl)propionic acid by both species. The latter reaction was shown to be catalyzed by the phloretin hydrolase from E. ramulus. PMID:15740074

Braune, Annett; Engst, Wolfram; Blaut, Michael

2005-03-01

115

Degradation of neohesperidin dihydrochalcone by human intestinal bacteria.  

UK PubMed Central (United Kingdom)

The degradation of neohesperidin dihydrochalcone by human intestinal microbiota was studied in vitro. Human fecal slurries converted neohesperidin dihydrochalcone anoxically to 3-(3-hydroxy-4-methoxyphenyl)propionic acid or 3-(3,4-dihydroxyphenyl)propionic acid. Two transient intermediates were identified as hesperetin dihydrochalcone 4'-beta-d-glucoside and hesperetin dihydrochalcone. These metabolites suggest that neohesperidin dihydrochalcone is first deglycosylated to hesperetin dihydrochalcone 4'-beta-d-glucoside and subsequently to the aglycon hesperetin dihydrochalcone. The latter is hydrolyzed to the corresponding 3-(3-hydroxy-4-methoxyphenyl)propionic acid and probably phloroglucinol. Eubacterium ramulus and Clostridium orbiscindens were not capable of converting neohesperidin dihydrochalcone. However, hesperetin dihydrochalcone 4'-beta-d-glucoside was converted by E. ramulus to hesperetin dihydrochalcone and further to 3-(3-hydroxy-4-methoxyphenyl)propionic acid, but not by C. orbiscindens. In contrast, hesperetin dihydrochalcone was cleaved to 3-(3-hydroxy-4-methoxyphenyl)propionic acid by both species. The latter reaction was shown to be catalyzed by the phloretin hydrolase from E. ramulus.

Braune A; Engst W; Blaut M

2005-03-01

116

Vasoactive intestinal polypeptide (VIP) innervation of the human eyelid glands.  

Science.gov (United States)

This study was conducted to obtain morphological proof of innervating nerve fibres in the glands of the human eyelid (accessory lacrimal glands of Wolfring, meibomian glands, goblet cells, glands of Zeis, glands of Moll, sweat glands, glands of lanugo hair follicles) and identification of the secretomotorically active neuropeptide vasoactive intestinal polypeptide (VIP) as a common transmitter. Epoxy-embedded ultrathin sections of tissue samples from human eyelids were studied using electron microscopy. Paraffin sections fixed in Bouin-Hollande solution were immunostained with rabbit antiserum against VIP. With the electron microscope we were able to identify nerves in the glandular stroma of all the glands examined with the exception of goblet cells. Intraepithelial single axons were only seen in the parenchyma of Wolfring glands. The morphological findings corresponded with the immunological finding of VIP-positive, nerve-like structures in the same locations, with the exception of lanugo hair follicle glands, and goblet cells. Our findings indicate that the glands of the eyelids and main lacrimal gland represent a functional unit with VIP as a possible common stimulating factor. PMID:10375432

Seifert, P; Spitznas, M

1999-06-01

117

In vitro behavior of human intestinal mucosa. The influence of acetyl choline on ion transport.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The possibility that the autonomic nervous system may influence the function of intestinal mucosa was investigated by assessing the effect of acetyl choline on ion transport in human intestine. Isolated pieces of stripped ileal mucosa were mounted in Perspex flux-chambers and bathed in isotonic gluc...

Isaacs, P E; Corbett, C L; Riley, A K; Hawker, P C; Turnberg, L A

118

Complex interactions among diet, gastrointestinal transit, and gut microbiota in humanized mice.  

UK PubMed Central (United Kingdom)

BACKGROUND & AIMS: Diet has major effects on the intestinal microbiota, but the exact mechanisms that alter complex microbial communities have been difficult to elucidate. In addition to the direct influence that diet exerts on microbes, changes in microbiota composition and function can alter host functions such as gastrointestinal (GI) transit time, which in turn can further affect the microbiota. METHODS: We investigated the relationships among diet, GI motility, and the intestinal microbiota using mice that are germ-free (GF) or humanized (ex-GF mice colonized with human fecal microbiota). RESULTS: Analysis of gut motility revealed that humanized mice fed a standard polysaccharide-rich diet had faster GI transit and increased colonic contractility compared with GF mice. Humanized mice with faster transit due to administration of polyethylene glycol or a nonfermentable cellulose-based diet had similar changes in gut microbiota composition, indicating that diet can modify GI transit, which then affects the composition of the microbial community. However, altered transit in mice fed a diet of fermentable fructooligosaccharide indicates that diet can change gut microbial function, which can affect GI transit. CONCLUSIONS: Based on studies in humanized mice, diet can affect GI transit through microbiota-dependent or microbiota-independent pathways, depending on the type of dietary change. The effect of the microbiota on transit largely depends on the amount and type (fermentable vs nonfermentable) of polysaccharides present in the diet. These results have implications for disorders that affect GI transit and gut microbial communities, including irritable bowel syndrome and inflammatory bowel disease.

Kashyap PC; Marcobal A; Ursell LK; Larauche M; Duboc H; Earle KA; Sonnenburg ED; Ferreyra JA; Higginbottom SK; Million M; Tache Y; Pasricha PJ; Knight R; Farrugia G; Sonnenburg JL

2013-05-01

119

Human Rights and Transitional Societies: Contemporary Challenges  

DEFF Research Database (Denmark)

This paper will assess how alternative approaches to transitional justice have the potential for overcoming tensions in between human rights standards. A rule in international law prescribing that states have a duty to prosecute gross human rights violations has emerged. Accordingly, transitional societies are said to have an obligation to apply criminal justice in dealing with such past violations. In Rwanda, the transitional government decided to prosecute the perpetrators of the 1994 genocide. As a result of widespread participation in the genocide and a devastated legal sector, difficulties in respecting the rights of the accused arose. A group of paralegals known as the "Corps of Judicial Defenders" was thus relied upon as to provide legal assistance for genocide suspects, but also for civil parties. This paper describes the work of these paralegals relating to the transitional trials, and, more generally, asserts how Judicial Defenders may have contributed to justice in other ways in post conflict Rwanda. The author argues that an efficient transitional justice policy must take sufficiently into account the context of the society in question, and aim at establishing linkages between justice in transitions and justice in the long-term.

Hansen, Thomas Obel

2008-01-01

120

Comparison of selective M3 and nonselective muscarinic receptor antagonists on gastrointestinal transit and bowel habits in humans.  

Science.gov (United States)

Although in vitro studies show that muscarinic M(3) receptors primarily mediate the effects of acetylcholine on gastrointestinal contractility, the muscarinic receptor subtypes regulating gastrointestinal motor activity and transit in humans in vivo are unclear. We hypothesized that muscarinic M(3)-specific but not nonspecific receptor antagonists would delay gastrointestinal and colonic transit in humans. In this parallel-group study, gastric emptying, small intestinal transit, and colonic transit were assessed by scintigraphy on days 4-6 in 72 healthy subjects (49 women) who received placebo (n = 16), the M(3) antagonist darifenacin ER [7.5 mg (n = 20) or 15 mg daily (n = 17)], or the nonspecific antagonist tolterodine [4 mg daily (n = 19)] for 6 days. Bowel habits were recorded by daily diaries. Both doses of darifenacin substantially delayed [P Darifenacin (15 mg) also delayed (P Darifenacin did not affect gastric emptying and tolterodine did not affect bowel habits or gastrointestinal transit. With muscarinic antagonists used at clinically approved doses, these findings demonstrate that muscarinic M(3) receptors regulate small intestinal and colonic transit in humans; colonic effects are more pronounced in the right than left colon. At doses that affect small and large intestinal transit, M(3) antagonists do not affect gastric emptying in humans. The efficacy of darifenacin in diarrhea-predominant irritable bowel syndrome should be evaluated. PMID:20395537

Bharucha, Adil E; Ravi, Karthik; Zinsmeister, Alan R

2010-04-15

 
 
 
 
121

Scintigraphic determination of the effect of metoclopramide and morphine on small intestinal transit time  

Energy Technology Data Exchange (ETDEWEB)

To determine if a scintigraphic method could detect pharmacologic changes in small intestinal transit time (SITT), 10 male volunteers were studied at baseline and after intravenously administered metoclopramide (10 mg) and morphine (8 mg). Five of these volunteers were studied with the hydrogen breath test method for comparison. For each of the scintigraphic studies, the volunteers were positioned supine under a large-field-of-view gamma camera after ingesting an isosmotic lactulose solution containing 99mtechnetium-diethylenetriaminepentaacetic acid (DTPA). Data were collected and stored in a computer. Both gastric emptying and SITT were determined. SITT was 81 +/- 11 min (mean +/- S.E.M.; N = 10) during baseline studies, was decreased significantly to 50 +/- 6 min (N = 10; P less than 0.01) after metoclopramide, and was increased significantly to 161 +/- 15 min (N = 8; P less than 0.01) after morphine. Baseline mean values were 86.3 +/- 15 min (N = 15) for the hydrogen breath tests, 47 +/- 8 min (N = 5) for metoclopramide, and 183 +/- 16 min (N = 5) for morphine. For gastric emptying, there was no significant difference in percentage emptying at 1 hr for baseline and metochopramide (82 +/- 5% vs. 88 +/- 4%). Morphine prolonged gastric emptying at 1 hr to 63 +/- 8%. We conclude that the scintigraphic method for measuring SITT permits accurate investigation of the pharmacologic effects on intestinal motility and, in addition, may be a useful research and clinical method for SITT determination.

Prokop, E.K.; Caride, V.J.; Winchenbach, K.; Troncale, F.J.; McCallum, R.W.

1988-01-01

122

Scintigraphic determination of the effect of metoclopramide and morphine on small intestinal transit time  

International Nuclear Information System (INIS)

To determine if a scintigraphic method could detect pharmacologic changes in small intestinal transit time (SITT), 10 male volunteers were studied at baseline and after intravenously administered metoclopramide (10 mg) and morphine (8 mg). Five of these volunteers were studied with the hydrogen breath test method for comparison. For each of the scintigraphic studies, the volunteers were positioned supine under a large-field-of-view gamma camera after ingesting an isosmotic lactulose solution containing 99mtechnetium-diethylenetriaminepentaacetic acid (DTPA). Data were collected and stored in a computer. Both gastric emptying and SITT were determined. SITT was 81 +/- 11 min (mean +/- S.E.M.; N = 10) during baseline studies, was decreased significantly to 50 +/- 6 min (N = 10; P less than 0.01) after metoclopramide, and was increased significantly to 161 +/- 15 min (N = 8; P less than 0.01) after morphine. Baseline mean values were 86.3 +/- 15 min (N = 15) for the hydrogen breath tests, 47 +/- 8 min (N = 5) for metoclopramide, and 183 +/- 16 min (N = 5) for morphine. For gastric emptying, there was no significant difference in percentage emptying at 1 hr for baseline and metochopramide (82 +/- 5% vs. 88 +/- 4%). Morphine prolonged gastric emptying at 1 hr to 63 +/- 8%. We conclude that the scintigraphic method for measuring SITT permits accurate investigation of the pharmacologic effects on intestinal motility and, in addition, may be a useful research and clinical method for SITT determination

1988-01-01

123

Mucosal lesions in the human small intestine in shock.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Characteristic mucosal lesions in resected small intestinal segments from seven patients are reported. Preoperatively, four patients were in shock and general hypotension while the three remaining cases showed signs of local intestinal hypotension. The microscopic appearance of the mucosal lesions w...

Haglund, U; Hultén, L; Ahren, C; Lundgren, O

124

The influence of intestinal dysbiosis on human's health  

Directory of Open Access Journals (Sweden)

Full Text Available Is it possible that a healthy diet could increase our body's resilience? Is it possible that the correct diet would allow us to avoid allergy or inflammatory bowel disease? It seems that undervalued microbiota colonizing our intestines have an essential influence on our health. Factors such as diet and stress, modulate the composition of intestinal flora and its metabolic activity to affect a number of physiological processes of our body. Some components of diet, especially the use of food preservatives and the oversupply of protein may induce carcinogenesis. Stress induces significant changes in the composition of intestinal flora and encourages the development of opportunistic species of bacteria. Currently intestinal dysbiosis is thought to be predisposing factor responsible for the development of civilization diseases such as obesity, cardiovascular diseases, allergies, and inflammatory bowel disease. So, do you care for your(s) intestinal bacteria? What do you choose to feed them?

Beata Magdalena Sobieszcza?ska

2008-01-01

125

5-Hydroxytryptamine and human small intestinal motility: effect of inhibiting 5-hydroxytryptamine reuptake.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Parenteral 5-hydroxytryptamine stimulates small intestinal motility, but the effect of continuous stimulation with 5-hydroxytryptamine on the human migrating motor complex is unknown. Using a selective 5-hydroxytryptamine reuptake inhibitor, paroxetine, this study investigated the effect of indirect...

Gorard, D A; Libby, G W; Farthing, M J

126

Conditions affecting cell surface properties of human intestinal bifidobacteria.  

Science.gov (United States)

The cell surface properties of human intestinal bifidobacteria have been characterized for 30 strains isolated from a fecal sample. Strain identification to the species level was obtained by restriction analysis of the amplified 16S rRNA gene and confirmed by DNA/DNA reassociation experiments. The isolates were grouped in four genetically homogeneous clusters whose members belonged to Bifidobacterium bifidum, Bifidobacterium adolescentis, Bifidobacterium longum and Bifidobacterium pseudocatenulatum species. Cell surface properties of Bifidobacterium strains were evaluated by determining the level of hydrophobicity, adhesion to hydrocarbons and contact angle measurements, and their autoaggregation ability. The results showed high and homogeneous level of hydrophobicity in all tested strains when contact angle measurements values were considered. On the contrary, autoaggregation assays and bacterial adhesion to hydrocarbons detected interesting differences in cell surface properties among the tested Bifidobacterium strains. The highest levels of autoaggregation, detected in B. bifidum and B. adolescentis strains, were strictly dependent on the pH of the medium. Moreover, protease treatment experiments suggested that proteins had a key role in the autoaggregating ability of B. bifidum and B. adolescentis strains. PMID:16284927

Canzi, Enrica; Guglielmetti, Simone; Mora, Diego; Tamagnini, Isabella; Parini, Carlo

127

Conditions affecting cell surface properties of human intestinal bifidobacteria.  

UK PubMed Central (United Kingdom)

The cell surface properties of human intestinal bifidobacteria have been characterized for 30 strains isolated from a fecal sample. Strain identification to the species level was obtained by restriction analysis of the amplified 16S rRNA gene and confirmed by DNA/DNA reassociation experiments. The isolates were grouped in four genetically homogeneous clusters whose members belonged to Bifidobacterium bifidum, Bifidobacterium adolescentis, Bifidobacterium longum and Bifidobacterium pseudocatenulatum species. Cell surface properties of Bifidobacterium strains were evaluated by determining the level of hydrophobicity, adhesion to hydrocarbons and contact angle measurements, and their autoaggregation ability. The results showed high and homogeneous level of hydrophobicity in all tested strains when contact angle measurements values were considered. On the contrary, autoaggregation assays and bacterial adhesion to hydrocarbons detected interesting differences in cell surface properties among the tested Bifidobacterium strains. The highest levels of autoaggregation, detected in B. bifidum and B. adolescentis strains, were strictly dependent on the pH of the medium. Moreover, protease treatment experiments suggested that proteins had a key role in the autoaggregating ability of B. bifidum and B. adolescentis strains.

Canzi E; Guglielmetti S; Mora D; Tamagnini I; Parini C

2005-10-01

128

Gut-on-a-Chip microenvironment induces human intestinal cells to undergo villus differentiation.  

Science.gov (United States)

Existing in vitro models of human intestinal function commonly rely on use of established epithelial cell lines, such as Caco-2 cells, which form polarized epithelial monolayers but fail to mimic more complex intestinal functions that are required for drug development and disease research. We show here that a microfluidic 'Gut-on-a-Chip' technology that exposes cultured cells to physiological peristalsis-like motions and liquid flow can be used to induce human Caco-2 cells to spontaneously undergo robust morphogenesis of three-dimensional (3D) intestinal villi. The cells of that line these villus structures are linked by tight junctions, and covered by brush borders and mucus. They also reconstitute basal proliferative crypts that populate the villi along the crypt-villus axis, and form four different types of differentiated epithelial cells (absorptive, mucus-secretory, enteroendocrine, and Paneth) that take characteristic positions similar to those observed in living human small intestine. Formation of these intestinal villi also results in exposure of increased intestinal surface area that mimics the absorptive efficiency of human intestine, as well enhanced cytochrome P450 3A4 isoform-based drug metabolizing activity compared to conventional Caco-2 cell monolayers cultured in a static Transwell system. The ability of the human Gut-on-a-Chip to recapitulate the 3D structures, differentiated cell types, and multiple physiological functions of normal human intestinal villi may provide a powerful alternative in vitro model for studies on intestinal physiology and digestive diseases, as well as drug development. PMID:23817533

Kim, Hyun Jung; Ingber, Donald E

2013-08-19

129

The Mucin degrader Akkermansia muciniphila is an abundant resident of the human intestinal tract.  

UK PubMed Central (United Kingdom)

A 16S rRNA-targeted probe, MUC-1437, was designed and validated in order to determine the presence and numbers of cells of Akkermansia muciniphila, a mucin degrader, in the human intestinal tract. As determined by fluorescent in situ hybridization, A. muciniphila accounted more than 1% of the total fecal cells and was shown to be a common bacterial component of the human intestinal tract.

Derrien M; Collado MC; Ben-Amor K; Salminen S; de Vos WM

2008-03-01

130

The Mucin degrader Akkermansia muciniphila is an abundant resident of the human intestinal tract.  

Science.gov (United States)

A 16S rRNA-targeted probe, MUC-1437, was designed and validated in order to determine the presence and numbers of cells of Akkermansia muciniphila, a mucin degrader, in the human intestinal tract. As determined by fluorescent in situ hybridization, A. muciniphila accounted more than 1% of the total fecal cells and was shown to be a common bacterial component of the human intestinal tract. PMID:18083887

Derrien, Muriel; Collado, M Carmen; Ben-Amor, Kaouther; Salminen, Seppo; de Vos, Willem M

2007-12-14

131

Characterization of intracellular pteroylpolyglutamate hydrolase (PPH) from human intestinal mucosa  

Energy Technology Data Exchange (ETDEWEB)

There are two forms of pteroylpolyglutamate hydrolase (PPH) in the human intestinal mucosa, one in the brush border membrane and the other intracellular; brush border PPH is an exopeptidase with optimal activity at pH 6.5 and a requirement for zinc. The presence study characterized human intracellular PPH and compared its properties to those of brush border PPH. Intracellular PPH was purified 30-fold. The enzyme had a MW of 75,000 by gel filtration, was optimally active at pH 4.5, and had an isoelectric point at pH 8.0. In contrast to brush border PPH, intracellular PPH was unstable at increasing temperatures, was unaffected by dialysis against chelating agents and showed no requirement for Zn/sup 2 +/. Using PteGlu/sub 2/(/sup 14/C)Glu as substrate, they demonstrated a K/sub m/ of 1.2 ..mu..M and increasing affinity for folates with longer glutamate chains. Intracellular PPH required the complete folic acid (PteGlu) moiety and a ..gamma..-glutamyl linkage for activity. Using ion exchange chromatography and an HPLC method to determine the hydrolytic products of the reaction, they found intracellular PPH could cleave both internal and terminal ..gamma..-glutamyl linkages, with PteGlu as an end product. After subcellular fractionation of the mucosa, PPH was found in the lysosomes. In summary, the distinct characteristics of brush border and intracellular PPH suggest that the two hydrolases serve different roles in folate metabolism.

Wang, T.T.Y.; Chandler, C.J.; Halsted, C.H.

1986-03-01

132

Biovolatilization of metal(loid)s by intestinal microorganisms in the simulator of the human intestinal microbial ecosystem.  

Science.gov (United States)

Methylation and hydrogenation of metal(loid)s by microorganisms are widespread and well-known processes in the environment by which mobility and in most cases toxicity are significantly enhanced in comparison to inorganic species. The human gut contains highly diverse and active microbiocenosis, yet little is known about the occurrence and importance of microbial metal(loid) methylation and hydrogenation. In this study, an in vitro gastrointestinal model, the Simulator of the Human Intestinal Microbial Ecosystem (SHIME),was used for investigating volatilization of metal(loid)s by intestinal microbiota. Suspensions from different compartments of the SHIME system analogous to different parts of the human intestinal tract were incubated with different concentrations of inorganic Ge, As, Se, Sn, Sb, Te, Hg, Pb, and Bi and analyzed by gas chromatography and inductively coupled plasma mass spectrometry (GC-ICP-MS). Significant volatilization was found for Se, As, and Te (maximal hourly production rates relative to the amount spiked; 0.6, 2, and 9 ng/mg/h, respectively). In addition, volatile species of Sb and Bi were detected. The occurrence of AsH3 and (CH3)2Te was toxicologically important. Furthermore, mixed Se/S and mixed As/S metabolites were detected in significant amounts in the gas phase of the incubation experiments of which two metabolites, (CH3)2AsSSCH3 and CH3As(SCH3)2, are described for the first time in environmental matrices. The toxicology of these species is unknown. These data show that the intestinal microbiota may increase the mobility of metal(loid)s, suggesting a significant modulation of their toxicity. Our research warrants further studies to investigate the extent of this process as well as the availability of metal(loid)s from different sources for microbial transformations. PMID:19708349

Diaz-Bone, Roland A; van de Wiele, Tom R

2009-07-15

133

Biovolatilization of metal(loid)s by intestinal microorganisms in the simulator of the human intestinal microbial ecosystem.  

UK PubMed Central (United Kingdom)

Methylation and hydrogenation of metal(loid)s by microorganisms are widespread and well-known processes in the environment by which mobility and in most cases toxicity are significantly enhanced in comparison to inorganic species. The human gut contains highly diverse and active microbiocenosis, yet little is known about the occurrence and importance of microbial metal(loid) methylation and hydrogenation. In this study, an in vitro gastrointestinal model, the Simulator of the Human Intestinal Microbial Ecosystem (SHIME),was used for investigating volatilization of metal(loid)s by intestinal microbiota. Suspensions from different compartments of the SHIME system analogous to different parts of the human intestinal tract were incubated with different concentrations of inorganic Ge, As, Se, Sn, Sb, Te, Hg, Pb, and Bi and analyzed by gas chromatography and inductively coupled plasma mass spectrometry (GC-ICP-MS). Significant volatilization was found for Se, As, and Te (maximal hourly production rates relative to the amount spiked; 0.6, 2, and 9 ng/mg/h, respectively). In addition, volatile species of Sb and Bi were detected. The occurrence of AsH3 and (CH3)2Te was toxicologically important. Furthermore, mixed Se/S and mixed As/S metabolites were detected in significant amounts in the gas phase of the incubation experiments of which two metabolites, (CH3)2AsSSCH3 and CH3As(SCH3)2, are described for the first time in environmental matrices. The toxicology of these species is unknown. These data show that the intestinal microbiota may increase the mobility of metal(loid)s, suggesting a significant modulation of their toxicity. Our research warrants further studies to investigate the extent of this process as well as the availability of metal(loid)s from different sources for microbial transformations.

Diaz-Bone RA; van de Wiele TR

2009-07-01

134

Espiroquetosis intestinal humana: serie clínica y revisión de la literatura/ Human intestinal spirochetosis: clinical series and literature review  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Introducción: La espiroquetosis intestinal humana (EIH) se define como la colonización del intestino grueso por espiroquetas. Se asocia a diarrea crónica. Su incidencia y prevalencia van desde 0,4 a 12% Objetivo: Determinar la prevalencia de EIH en el Hospital Del Salvador, de Santiago, Chile, entre los años 2003 y 2008, en pacientes con antecedentes clínicos de diarrea crónica y colonoscopia sin hallazgos patológicos, separados en dos grupos: pacientes con y sin a (more) ntecedentes de infección por VIH. Material y Método: Evaluación morfológica retrospectiva de las biopsias endoscópicas de intestino grueso de los grupos seleccionados. Resultados: Se revisaron 115 biopsias, 98 correspondieron a pacientes sin infección por VIH y 17 a pacientes seropositivos para VIH. Se detectaron dos casos de espiroquetosis intestinal, ambos en pacientes sin infección por VIH, con una prevalencia de 1,7 %. Comentario: La prevalencia de EIH es similar a la publicada en países occidentales. Se requieren estudios poblacionales para determinar el real impacto epidemiológico en nuestro medio. Abstract in english Introduction: Human intestinal spirochetosis (HIE) is defined as colonization by spirochetes of the large intestine. Is associated with chronic diarrhea. The incidence and prevalence ranges from 0.4% to 12%. Objective: To determine the prevalence of HIE in the Salvador's Hospital, between 2003 and 2008 in patients with a history of chronic diarrhea and without abnormalities in colonoscopy, in 2 separate groups: patients with and without a history of HIV infection. Materia (more) l and Methods: Retrospective morphology evaluation of the large bowel endoscopic biopsies to the selected groups. Results: We reviewed 115 biopsies, 98 were from HIV-negative and 17 HIV from positive patients. Two cases of intestinal spirochetosis were detected, both HIV negative, with a prevalence of 1.7%. Comment: The prevalence of HIE is similar to that reported in Western countries. Population studies are needed to determine the real epidemiological impact in our environment.

Lozano, Carlo; Arellano, Leonardo; Yaquich, Pamela

2012-08-01

135

Magnetoenterography (MENG): noninvasive measurement of bioelectric activity in human small intestine.  

UK PubMed Central (United Kingdom)

The basic electrical rhythm (BER) of the gastrointestinal tract creates minute magnetic fields that have been measured in animals using a Superconducting QUantum Interference Device (SQUID) gradiometer. The aim of this study was to measure noninvasively the biomagnetic fields of human stomach and small intestine. Twenty-one human volunteers were studied using a 37-channel SQUID gradiometer positioned over the epigastrium and umbilicus. In one volunteer additional biomagnetic recordings were performed in order to map the spatial variation of the biomagnetic fields. Cyclical waveforms consistent with gastric BER [3.0+/-0.5 cycles per minute (cpm)] and small intestine BER (10.26+/-1.74 cpm) were seen in the epigastrium and umbilicus, respectively. The mapping study identified the expected frequency gradient (12.0 cpm in duodenum, 11.3 cpm in jejunum, to 9.7 cpm in ileum) within the small intestine. Noninvasive recordings of human gastric and small intestinal BER can be obtained using a SQUID gradiometer.

Richards WO; Bradshaw LA; Staton DJ; Garrard CL; Liu F; Buchanan S; Wikswo JP Jr

1996-12-01

136

Laminin Receptor 37/67LR Regulates Adhesion and Proliferation of Normal Human Intestinal Epithelial Cells.  

Science.gov (United States)

Interactions between the cell basal membrane domain and the basement membrane are involved in several cell functions including proliferation, migration and differentiation. Intestinal epithelial cells can interact with laminin, a major intestinal basement membrane glycoprotein, via several cell-surface laminin-binding proteins including integrin and non-integrin receptors. The 37/67kDa laminin receptor (37/67LR) is one of these but its role in normal epithelial cells is still unknown. The aim of this study was to characterise the expression pattern and determine the main function of 37/67LR in the normal human small intestinal epithelium. Immunolocalization studies revealed that 37/67LR was predominantly present in the undifferentiated/proliferative region of the human intestinal crypt in both the immature and adult intestine. Using a human intestinal epithelial crypt (HIEC) cell line as experimental model, we determined that 37/67LR was expressed in proliferative cells in both the cytoplasmic and membrane compartments. Small-interfering RNA-mediated reduction of 37/67LR expression led to HIEC cell-cycle reduction and loss of the ability to adhere to laminin-related peptides under conditions not altering ribosomal function. Taken together, these findings indicate that 37/67LR regulates proliferation and adhesion in normal intestinal epithelial cells independently of its known association with ribosomal function. PMID:23991217

Khalfaoui, Taoufik; Groulx, Jean-François; Sabra, Georges; Guezguez, Amel; Basora, Nuria; Vermette, Patrick; Beaulieu, Jean-François

2013-08-22

137

Laminin Receptor 37/67LR Regulates Adhesion and Proliferation of Normal Human Intestinal Epithelial Cells.  

UK PubMed Central (United Kingdom)

Interactions between the cell basal membrane domain and the basement membrane are involved in several cell functions including proliferation, migration and differentiation. Intestinal epithelial cells can interact with laminin, a major intestinal basement membrane glycoprotein, via several cell-surface laminin-binding proteins including integrin and non-integrin receptors. The 37/67kDa laminin receptor (37/67LR) is one of these but its role in normal epithelial cells is still unknown. The aim of this study was to characterise the expression pattern and determine the main function of 37/67LR in the normal human small intestinal epithelium. Immunolocalization studies revealed that 37/67LR was predominantly present in the undifferentiated/proliferative region of the human intestinal crypt in both the immature and adult intestine. Using a human intestinal epithelial crypt (HIEC) cell line as experimental model, we determined that 37/67LR was expressed in proliferative cells in both the cytoplasmic and membrane compartments. Small-interfering RNA-mediated reduction of 37/67LR expression led to HIEC cell-cycle reduction and loss of the ability to adhere to laminin-related peptides under conditions not altering ribosomal function. Taken together, these findings indicate that 37/67LR regulates proliferation and adhesion in normal intestinal epithelial cells independently of its known association with ribosomal function.

Khalfaoui T; Groulx JF; Sabra G; Guezguez A; Basora N; Vermette P; Beaulieu JF

2013-01-01

138

The effect of Saccharomyces boulardii on Candida albicans-infected human intestinal cell lines Caco-2 and Intestin 407.  

UK PubMed Central (United Kingdom)

Saccharomyces boulardii is a probiotic strain that confers many benefits to human enterocolopathies and is used against a number of enteric pathogens. Candida albicans is an opportunistic pathogen that causes intestinal infections in immunocompromised patients, and after translocation into the bloodstream, is responsible for serious systemic candidiasis. In this study, we investigated the influence of S. boulardii cells and its culture extract on C. albicans adhesion to Caco-2 and Intestin 407 cell lines. We also tested the proinflammatory IL-1beta, IL-6 and IL-8 cytokine expression by C. albicans-infected Caco-2 cells, using real-time RT-PCR. We found that both S. boulardii and its extract significantly inhibited C. albicans adhesion to epithelial cell lines. The IL-8 gene expression by C. albicans-infected Caco-2 cells was suppressed by the addition of S. boulardii extract. Our results indicate that S. boulardii affects C. albicans adhesion and reduces cytokine-mediated inflammatory host response.

Murzyn A; Krasowska A; Augustyniak D; Majkowska-Skrobek G; ?ukaszewicz M; Dziadkowiec D

2010-09-01

139

Splitting the scotoperiod: effects on feeding behaviour, intestinal fill and digestive transit time in broiler chickens  

DEFF Research Database (Denmark)

1. The aim of this study was to evaluate how splitting the dark period (scotoperiod) affects feeding behaviour and associated intestinal measures in broilers. 2. Ross 308 broilers were reared to 37 d in groups given either a daily 8-h continuous scotoperiod (DARK 8) or an intermittent light schedule with two equally spaced 4-h scotoperiods (DARK 4þ4), which yielded the same total duration of darkness per 24 h. 3. Feeding behaviour was recorded weekly from 24-h video recordings of 24 groups each of 64 birds. Empty intestinal weights as well as their contents were measured weekly at 4 time points (n¼192). Digestive transit time was estimated on d 29 using a chromic oxide marker; production variables and the extent of foot pad dermatitis were also recorded. 4. In the 3 h prior to a scotoperiod, feeding activity increased in chickens from DARK 8 but not DARK 4þ4. This increase was reflected in a higher relative content of the crop in DARK 8 at this time. 5. Immediately following the scotoperiod, feeding activity peaked and, although the chickens in DARK 4þ4 expressed more feeding behaviour in the first 20 min after the scotoperiod, the chickens in DARK 8 had overall higher feeding activity across the day. However, DARK 4þ4 had a higher feed intake and weight gain. The occurrence and severity of foot pad dermatitis was similar between treatments. 6. In conclusion, broilers modify their feeding behaviour according to the prevailing light schedule. Eight consecutive hours of darkness reduced growth, but did not affect overall feed conversion efficiency, and did not appear to exacerbate hunger or foot pad dermatitis to any great extent.

Duve, Linda Rosager; Steenfeldt, Sanna

2011-01-01

140

Cell wall fragments from major residents of the human intestinal flora induce chronic arthritis in rats.  

UK PubMed Central (United Kingdom)

To investigate the involvement of human intestinal flora in joint inflammation, cell wall fragments of 9 anaerobic gram positive bacteria of the human fecal flora were prepared and tested for arthropathic properties in the rat. A single intraperitoneal injection of cell wall fragments from Eubacterium aerofaciens or Bifidobacterium species induced persistent chronic arthritis, in contrast to those from Eubacterium rectale, Clostridium species and Lactobacillus leichmanii. The results show that cell wall fragments of major residents from the human fecal flora can induce chronic arthritis in the rat and support the hypothesis that normal human intestinal flora plays a role in the induction of arthritis in man.

Severijnen AJ; van Kleef R; Hazenberg MP; van de Merwe JP

1989-08-01

 
 
 
 
141

Interindividual variability of carboxymethylenebutenolidase homolog, a novel olmesartan medoxomil hydrolase, in the human liver and intestine.  

UK PubMed Central (United Kingdom)

Olmesartan medoxomil (OM) is a prodrug-type angiotensin II type 1 receptor antagonist. OM is rapidly converted into its active metabolite olmesartan by multiple hydrolases in humans, and we recently identified carboxymethylenebutenolidase homolog (CMBL) as one of the OM bioactivating hydrolases. In the present study, we further investigated the interindividual variability of mRNA and protein expression of CMBL and OM-hydrolase activity using 40 individual human liver and 30 intestinal specimens. In the intestinal samples, OM-hydrolase activity strongly correlated with the CMBL protein expression, clearly indicating that CMBL is a major contributor to the prodrug bioactivation in human intestine. The protein and activity were highly distributed in the proximal region (duodenum and jejunum) and decreased to the distal region of the intestine. Although there was high interindividual variability (16-fold) in both the protein and activity in the intestinal segments from the duodenum to colon, the interindividual variability in the duodenum and jejunum was relatively small (3.0- and 2.4-fold, respectively). In the liver samples, the interindividual variability in the protein and activity was 4.1- and 6.8-fold, respectively. No sex differences in the protein and activity were shown in the human liver or intestine. A genetically engineered Y155C mutant of CMBL, which was caused by a single nucleotide polymorphism rs35489000, showed significantly lower OM-hydrolase activity than the wild-type protein although no minor allele was genotyped in the 40 individual liver specimens.

Ishizuka T; Rozehnal V; Fischer T; Kato A; Endo S; Yoshigae Y; Kurihara A; Izumi T

2013-05-01

142

Interindividual variability of carboxymethylenebutenolidase homolog, a novel olmesartan medoxomil hydrolase, in the human liver and intestine.  

Science.gov (United States)

Olmesartan medoxomil (OM) is a prodrug-type angiotensin II type 1 receptor antagonist. OM is rapidly converted into its active metabolite olmesartan by multiple hydrolases in humans, and we recently identified carboxymethylenebutenolidase homolog (CMBL) as one of the OM bioactivating hydrolases. In the present study, we further investigated the interindividual variability of mRNA and protein expression of CMBL and OM-hydrolase activity using 40 individual human liver and 30 intestinal specimens. In the intestinal samples, OM-hydrolase activity strongly correlated with the CMBL protein expression, clearly indicating that CMBL is a major contributor to the prodrug bioactivation in human intestine. The protein and activity were highly distributed in the proximal region (duodenum and jejunum) and decreased to the distal region of the intestine. Although there was high interindividual variability (16-fold) in both the protein and activity in the intestinal segments from the duodenum to colon, the interindividual variability in the duodenum and jejunum was relatively small (3.0- and 2.4-fold, respectively). In the liver samples, the interindividual variability in the protein and activity was 4.1- and 6.8-fold, respectively. No sex differences in the protein and activity were shown in the human liver or intestine. A genetically engineered Y155C mutant of CMBL, which was caused by a single nucleotide polymorphism rs35489000, showed significantly lower OM-hydrolase activity than the wild-type protein although no minor allele was genotyped in the 40 individual liver specimens. PMID:23471504

Ishizuka, Tomoko; Rozehnal, Veronika; Fischer, Thomas; Kato, Ayako; Endo, Seiko; Yoshigae, Yasushi; Kurihara, Atsushi; Izumi, Takashi

2013-03-07

143

Deoxycholic acid formation in gnotobiotic mice associated with human intestinal bacteria.  

Science.gov (United States)

In humans and animals, intestinal flora is indispensable for bile acid transformation. The goal of our study was to establish gnotobiotic mice with intestinal bacteria of human origin in order to examine the role of intestinal bacteria in the transformation of bile acids in vivo using the technique of gnotobiology. Eight strains of bile acid-deconjugating bacteria were isolated from ex-germ-free mice inoculated with a human fecal dilution of 10(-6), and five strains of 7alpha-dehydroxylating bacteria were isolated from the intestine of limited human flora mice inoculated only with clostridia. The results of biochemical tests and 16S rDNA sequence analysis showed that seven out of eight bile acid-deconjugating strains belong to a bacteroides cluster (Bacteroides vulgatus, B. distasonis, and B. uniformis), and one strain had high similarity with Bilophila wadsworthia. All five strains that converted cholic acid to deoxycholic acid had greatest similarity with Clostridium hylemonae. A combination of 10 isolated strains converted taurocholic acid into deoxycholic acid both in vitro and in the mouse intestine. These results indicate that the predominant bacteria, mainly Bacteroides, in human feces comprise one of the main bacterial groups for the deconjugation of bile acids, and clostridia may play an important role in 7aplha-dehydroxylation of free-form primary bile acids in the intestine although these strains are not predominant. The gnotobiotic mouse with bacteria of human origin could be a useful model in studies of bile acid metabolism by human intestinal bacteria in vivo. PMID:17152920

Narushima, Seiko; Itoha, Kikuji; Miyamoto, Yukiko; Park, Sang-Hee; Nagata, Keiko; Kuruma, Kazuo; Uchida, Kiyohisa

2006-09-01

144

The human small intestinal microbiota is driven by rapid uptake and conversion of simple carbohydrates  

DEFF Research Database (Denmark)

The human gastrointestinal tract (GI tract) harbors a complex community of microbes. The microbiota composition varies between different locations in the GI tract, but most studies focus on the fecal microbiota, and that inhabiting the colonic mucosa. Consequently, little is known about the microbiota at other parts of the GI tract, which is especially true for the small intestine because of its limited accessibility. Here we deduce an ecological model of the microbiota composition and function in the small intestine, using complementing culture-independent approaches. Phylogenetic microarray analyses demonstrated that microbiota compositions that are typically found in effluent samples from ileostomists (subjects without a colon) can also be encountered in the small intestine of healthy individuals. Phylogenetic mapping of small intestinal metagenome of three different ileostomy effluent samples from a single individual indicated that Streptococcus sp., Escherichia coli, Clostridium sp. and high G+C organisms are most abundant in the small intestine. The compositions of these populations fluctuated in time and correlated to the short-chain fatty acids profiles that were determined in parallel. Comparative functional analysis with fecal metagenomes identified functions that are overrepresented in the small intestine, including simple carbohydrate transport phosphotransferase systems (PTS), central metabolism and biotin production. Moreover, metatranscriptome analysis supported high level in-situ expression of PTS and carbohydrate metabolic genes, especially those belonging to Streptococcus sp. Overall, our findings suggest that rapid uptake and fermentation of available carbohydrates contribute to maintaining the microbiota in the human small intestine.

Zoetendal, Erwin G; Raes, Jeroen

2012-01-01

145

The human small intestinal microbiota is driven by rapid uptake and conversion of simple carbohydrates.  

UK PubMed Central (United Kingdom)

The human gastrointestinal tract (GI tract) harbors a complex community of microbes. The microbiota composition varies between different locations in the GI tract, but most studies focus on the fecal microbiota, and that inhabiting the colonic mucosa. Consequently, little is known about the microbiota at other parts of the GI tract, which is especially true for the small intestine because of its limited accessibility. Here we deduce an ecological model of the microbiota composition and function in the small intestine, using complementing culture-independent approaches. Phylogenetic microarray analyses demonstrated that microbiota compositions that are typically found in effluent samples from ileostomists (subjects without a colon) can also be encountered in the small intestine of healthy individuals. Phylogenetic mapping of small intestinal metagenome of three different ileostomy effluent samples from a single individual indicated that Streptococcus sp., Escherichia coli, Clostridium sp. and high G+C organisms are most abundant in the small intestine. The compositions of these populations fluctuated in time and correlated to the short-chain fatty acids profiles that were determined in parallel. Comparative functional analysis with fecal metagenomes identified functions that are overrepresented in the small intestine, including simple carbohydrate transport phosphotransferase systems (PTS), central metabolism and biotin production. Moreover, metatranscriptome analysis supported high level in-situ expression of PTS and carbohydrate metabolic genes, especially those belonging to Streptococcus sp. Overall, our findings suggest that rapid uptake and fermentation of available carbohydrates contribute to maintaining the microbiota in the human small intestine.

Zoetendal EG; Raes J; van den Bogert B; Arumugam M; Booijink CC; Troost FJ; Bork P; Wels M; de Vos WM; Kleerebezem M

2012-07-01

146

Animal and human models for studying effects of drugs on intestinal fluid transport in vivo.  

Science.gov (United States)

The understanding of the physiology and pathophysiology of intestinal fluid transport has been derived from animal and human models of normal and perturbed intestines. This understanding helped in designing drugs and changing the composition of oral rehydration solutions in a targeted manner to affect intestinal fluid absorption/secretion that was tested both in vitro and in vivo before embarking on clinical trials. In this review, in vivo techniques used to study water transport in both animal and human models are described. In particular, steady state intestinal perfusion techniques, closed segment techniques, fistulous animal models, balance study models, enteropooling models, and isotope tracer models are reviewed. Advantages and drawbacks of each technique and examples where drug effects have been studied in a particular model are provided. PMID:15233962

Mourad, Fadi H

147

Nucleotide and amino acid sequences of human intestinal alkaline phosphatase: close homology to placental alkaline phosphatase  

International Nuclear Information System (INIS)

[en] A cDNA clone for human adult intestinal alkaline phosphatase (ALP) [orthophosphoric-monoester phosphohydrolase (alkaline optimum); EC 3.1.3.1] was isolated from a ?gt11 expression library. The cDNA insert of this clone is 2513 base pairs in length and contains an open reading frame that encodes a 528-amino acid polypeptide. This deduced polypeptide contains the first 40 amino acids of human intestinal ALP, as determined by direct protein sequencing. Intestinal ALP shows 86.5% amino acid identity to placental (type 1) ALP and 56.6% amino acid identity to liver/bone/kidney ALP. In the 3'-untranslated regions, intestinal and placental ALP cDNAs are 73.5% identical (excluding gaps). The evolution of this multigene enzyme family is discussed

1987-01-01

148

Association between the ABO blood group and the human intestinal microbiota composition.  

UK PubMed Central (United Kingdom)

BACKGROUND: The mucus layer covering the human intestinal epithelium forms a dynamic surface for host-microbial interactions. In addition to the environmental factors affecting the intestinal equilibrium, such as diet, it is well established that the microbiota composition is individually driven, but the host factors determining the composition have remained unresolved. RESULTS: In this study, we show that ABO blood group is involved in differences in relative proportion and overall profiles of intestinal microbiota. Specifically, the microbiota from the individuals harbouring the B antigen (secretor B and AB) differed from the non-B antigen groups and also showed higher diversity of the Eubacterium rectale-Clostridium coccoides (EREC) and Clostridium leptum (CLEPT) -groups in comparison with other blood groups. CONCLUSIONS: Our novel finding indicates that the ABO blood group is one of the genetically determined host factors modulating the composition of the human intestinal microbiota, thus enabling new applications in the field of personalized nutrition and medicine.

Mäkivuokko H; Lahtinen SJ; Wacklin P; Tuovinen E; Tenkanen H; Nikkilä J; Björklund M; Aranko K; Ouwehand AC; Mättö J

2012-01-01

149

Association between the ABO blood group and the human intestinal microbiota composition  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The mucus layer covering the human intestinal epithelium forms a dynamic surface for host-microbial interactions. In addition to the environmental factors affecting the intestinal equilibrium, such as diet, it is well established that the microbiota composition is individually driven, but the host factors determining the composition have remained unresolved. Results In this study, we show that ABO blood group is involved in differences in relative proportion and overall profiles of intestinal microbiota. Specifically, the microbiota from the individuals harbouring the B antigen (secretor B and AB) differed from the non-B antigen groups and also showed higher diversity of the Eubacterium rectale-Clostridium coccoides (EREC) and Clostridium leptum (CLEPT) -groups in comparison with other blood groups. Conclusions Our novel finding indicates that the ABO blood group is one of the genetically determined host factors modulating the composition of the human intestinal microbiota, thus enabling new applications in the field of personalized nutrition and medicine.

Mäkivuokko Harri; Lahtinen Sampo J; Wacklin Pirjo; Tuovinen Elina; Tenkanen Heli; Nikkilä Janne; Björklund Marika; Aranko Kari; Ouwehand Arthur C; Mättö Jaana

2012-01-01

150

Nucleotide and amino acid sequences of human intestinal alkaline phosphatase: close homology to placental alkaline phosphatase  

Energy Technology Data Exchange (ETDEWEB)

A cDNA clone for human adult intestinal alkaline phosphatase (ALP) (orthophosphoric-monoester phosphohydrolase (alkaline optimum); EC 3.1.3.1) was isolated from a lambdagt11 expression library. The cDNA insert of this clone is 2513 base pairs in length and contains an open reading frame that encodes a 528-amino acid polypeptide. This deduced polypeptide contains the first 40 amino acids of human intestinal ALP, as determined by direct protein sequencing. Intestinal ALP shows 86.5% amino acid identity to placental (type 1) ALP and 56.6% amino acid identity to liver/bone/kidney ALP. In the 3'-untranslated regions, intestinal and placental ALP cDNAs are 73.5% identical (excluding gaps). The evolution of this multigene enzyme family is discussed.

Henthorn, P.S.; Raducha, M.; Edwards, Y.H.; Weiss, M.J.; Slaughter, C.; Lafferty, M.A.; Harris, H.

1987-03-01

151

Isolation and identification of intestinal CYP3A inhibitors from cranberry (Vaccinium macrocarpon) using human intestinal microsomes.  

UK PubMed Central (United Kingdom)

Cranberry juice is used routinely, especially among women and the elderly, to prevent and treat urinary tract infections. These individuals are likely to be taking medications concomitantly with cranberry juice, leading to concern about potential drug-dietary substance interactions, particularly in the intestine, which, along with the liver, is rich in expression of the prominent drug metabolizing enzyme, cytochrome P450 3A (CYP3A). Using a systematic in vitro-in vivo approach, a cranberry juice product was identified recently that elicited a pharmacokinetic interaction with the CYP3A probe substrate midazolam in 16 healthy volunteers. Relative to water, cranberry juice inhibited intestinal first-pass midazolam metabolism. In vitro studies were initiated to identify potential enteric CYP3A inhibitors from cranberry via a bioactivity-directed fractionation approach involving dried whole cranberry [Vaccinium macrocarpon Ait. (Ericaceae)], midazolam, and human intestinal microsomes (HIM). Three triterpenes (maslinic acid, corosolic acid, and ursolic acid) were isolated. The inhibitory potency (IC(50)) of maslinic acid, corosolic acid, and ursolic acid was 7.4, 8.8, and < 10 µM, respectively, using HIM as the enzyme source and 2.8, 4.3, and < 10 µM, respectively, using recombinant CYP3A4 as the enzyme source. These in vitro inhibitory potencies, which are within the range of those reported for two CYP3A inhibitory components in grapefruit juice, suggest that these triterpenes may have contributed to the midazolam-cranberry juice interaction observed in the clinical study.

Kim E; Sy-Cordero A; Graf TN; Brantley SJ; Paine MF; Oberlies NH

2011-02-01

152

Intestinal absorption, metabolism, and excretion of (-)-epicatechin in healthy humans assessed by using an intestinal perfusion technique.  

UK PubMed Central (United Kingdom)

BACKGROUND: (-)-Epicatechin is a dietary flavonoid present in many foods that affects vascular function, but its action is limited by incomplete absorption, conjugation, and metabolism. Factors that influence this activity may attributed to instability in the gastrointestinal lumen, low permeability across the intestinal wall, or active efflux from enterocytes and extensive conjugation. OBJECTIVE: With the use of a multilumen perfusion catheter, we investigated the jejunal absorption, systemic availability, metabolism, and intestinal, biliary, and urinary excretion of (-)-epicatechin in humans. DESIGN: In a single-center, randomized, open, controlled study in 8 healthy volunteers, 50 mg purified (-)-epicatechin was perfused into an isolated jejunal segment together with antipyrine as a marker for absorption. (-)-Epicatechin and conjugates were measured in intestinal perfusates, bile, plasma, and urine. RESULTS: Forty-six percent of the dose was recovered in the perfusate either as unchanged (-)-epicatechin (22 mg) or conjugates (0.8 mg); with stability taken into account, this result indicates that ?46% of the dose had apparently been absorbed. The conjugates were predominantly sulfates, which indicated conjugation by sulfotransferases followed by efflux from the enterocytes. In contrast, epicatechin glucuronides were dominant in plasma, bile, and urine. CONCLUSIONS: Almost one-half of the (-)-epicatechin is apparently absorbed in the jejunum but with substantial interindividual differences in the extent of absorption. The data suggest that the nature and substitution position of (-)-epicatechin conjugation are major determinants of the metabolic fate in the body, influencing whether the compound is effluxed into the lumen or absorbed into the blood and subsequently excreted.

Actis-Goretta L; Lévèques A; Rein M; Teml A; Schäfer C; Hofmann U; Li H; Schwab M; Eichelbaum M; Williamson G

2013-07-01

153

Bovine lactoferrin induces interleukin-11 production in a hepatitis mouse model and human intestinal myofibroblasts.  

UK PubMed Central (United Kingdom)

PURPOSE: Orally administered bovine lactoferrin (bLF) exerts an anti-inflammatory effect on hepatitis and colitis animal models. To investigate the mechanism underlying the action of bLF, we explored the expression of inflammation-related factors in the intestine of a hepatitis mouse model after the oral administration of bLF and in several human intestinal cell lines treated with bLF. METHODS: The effects of bLF on the expression of interleukin-11 (IL-11) and bone morphogenetic protein 2 (BMP2) in the intestinal mucosa of a hepatitis mouse model as well as in cell cultures of human intestinal epithelial cells, myofibroblasts, and monocytes were examined using the real-time reverse transcription polymerase chain reaction. Epithelial cells and myofibroblasts were also cocultured using transwells. bLF transport, and IL-11 and BMP2 induction, as well as the interactions between the two cell types, were then analyzed after bLF treatment. RESULTS: In vivo, oral bLF administration increased the production of IL-11 and BMP2 in intestinal specimens. In vitro, bLF only stimulated the production of IL-11 in human intestinal myofibroblasts; i.e., it had no effect on BMP2 production in any cell type. In the transwell cocultures, bLF passed through the epithelium and directly stimulated IL-11 production in the myofibroblasts on the basolateral side. The IL-11 produced in the myofibroblasts subsequently acted protectively on the epithelial cells of the coculture. CONCLUSIONS: bLF upregulated the activity of anti-inflammatory factors, such as IL-11, in the intestine of a hepatitis mouse model and human intestinal myofibroblasts.

Kuhara T; Yamauchi K; Iwatsuki K

2012-04-01

154

Epithelial-mesenchymal transition phenotype is associated with patient survival in small intestinal adenocarcinoma.  

UK PubMed Central (United Kingdom)

AIMS: We investigated the clinical significance of epithelial-mesenchymal transition (EMT) phenotype in 184 small intestinal adenocarcinomas (SIACs) based on the expression pattern of EMT-related proteins in cancer cells. METHODS: Immunohistochemistry for epithelial (E-cadherin) and mesenchymal (vimentin and fibronectin) markers were performed and cases of SIAC were classified into four subtypes of EMT: complete type (E-cadherin-, vimentin+ and/or fibronectin+), wild type (E-cadherin+, vimentin-, fibronectin-), incomplete 1 type (hybrid type; E-cadherin+, vimentin+ and/or fibronectin+), and incomplete 2 type (null type; E-cadherin-, vimentin-, fibronectin-). RESULTS: We identified 19 (10.3%) cases of complete EMT type, 86 (46.7%) cases of wild type and 79 (43%) cases of incomplete EMT type [hybrid type, 22 (12%) cases; null type, 57 (31%) cases]. Complete EMT phenotype showed a significant association with undifferentiated histology (p?

Kim A; Bae YK; Gu MJ; Kim JY; Jang KY; Bae HI; Lee HJ; Hong SM

2013-10-01

155

Monitoring and survival of Lactobacillus gasseri SBT2055 in the human intestinal tract.  

UK PubMed Central (United Kingdom)

The monitoring and survival of Lactobacillus gasseri SBT2055 in the human intestinal tract was investigated with seven healthy subjects having a low number of fecal lactobacilli. An increase of fecal lactobacilli (10(3.2-5.2) CFU/g feces) was recognized after ingestion of yogurt with SBT2055 by the subjects. A high positive rate of L. gasseri in fecal lactobacilli detected from the subjects (over 70% at 2nd weeks of feeding) was also observed during the ingestion period using the species-specific PCR system. These findings indicate that the SBT2055 strain in yogurt survived in the human intestinal tract and was recovered from human feces.

Takahashi H; Fujita T; Suzuki Y; Benno Y

2006-01-01

156

Composition for reducing secondary effects of adult gastroenteritis, comprising intestinal antiseptic or transit modifier, plus glucose and sucrose at ratio giving specific osmolality for optimum rehydration effect  

UK PubMed Central (United Kingdom)

In a treatment and rehydration composition (A) for reducing the secondary effects of gastroenteritis in adults, comprising an intestinal antiseptic (e.g. nifuroxazide) or an intestinal transit modifier (e.g. loperamide or a clay), glucose and sucrose, the ratio of glucose to sucrose is such that the osmolality is 260-290 (especially 280) mOsm.

AUZERIE JACK

157

High taxonomic level fingerprint of the human intestinal microbiota by Ligase Detection Reaction - Universal Array approach  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Affecting the core functional microbiome, peculiar high level taxonomic unbalances of the human intestinal microbiota have been recently associated with specific diseases, such as obesity, inflammatory bowel diseases, and intestinal inflammation. Results In order to specifically monitor microbiota unbalances that impact human physiology, here we develop and validate an original DNA-microarray (HTF-Microbi.Array) for the high taxonomic level fingerprint of the human intestinal microbiota. Based on the Ligase Detection Reaction-Universal Array (LDR-UA) approach, the HTF-Microbi.Array enables specific detection and approximate relative quantification of 16S rRNAs from 30 phylogenetically related groups of the human intestinal microbiota. The HTF-Microbi.Array was used in a pilot study of the faecal microbiota of eight young adults. Cluster analysis revealed the good reproducibility of the high level taxonomic microbiota fingerprint obtained for each of the subject. Conclusion The HTF-Microbi.Array is a fast and sensitive tool for the high taxonomic level fingerprint of the human intestinal microbiota in terms of presence/absence of the principal groups. Moreover, analysis of the relative fluorescence intensity for each probe pair of our LDR-UA platform can provide estimation of the relative abundance of the microbial target groups within each samples. Focusing the phylogenetic resolution at division, order and cluster levels, the HTF-Microbi.Array is blind with respect to the inter-individual variability at the species level.

Candela Marco; Consolandi Clarissa; Severgnini Marco; Biagi Elena; Castiglioni Bianca; Vitali Beatrice; De Bellis Gianluca; Brigidi Patrizia

2010-01-01

158

In vitro immunoglobulin synthesis by human intestinal lamina propria lymphocytes.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The concentration of IgG and IgA was measured in the supernatants of peripheral blood mononuclear cells and of cells harvested from the intestinal lamina propria, which were cultured in vitro in the presence or absence of mitogens. The lamina propria mononuclear cells were harvested by collagenase d...

Drew, P A; La Brooy, J T; Shearman, D J

159

A morphological analysis of the transition between the embryonic primitive intestine and yolk sac in bovine embryos and fetuses.  

Science.gov (United States)

The yolk sac (YS) is the main source of embryonic nutrition during the period when the placenta has not yet formed. It is also responsible for hematopoiesis because the blood cells develop from it as part of the primitive embryonic circulation. The objective of this study was to characterize the transitional area between the YS and primitive gut using the techniques of light microscopy, transmission electron microscopy, and immunohistochemistry to detect populations of pluripotent cells by labeling with Oct4 antibody. In all investigated embryos, serial sections were made to permit the identification of this small, restricted area. We identified the YS connection with the primitive intestine and found that it is composed of many blood islands, which correspond to the vessels covered by vitelline and mesenchymal cells. We identified large numbers of hemangioblasts inside the vessels. The mesenchymal layer was thin and composed of elongated cells, and the vitelline endodermal membrane was composed of large, mono- or binucleated cells. The epithelium of the primitive intestine comprised stratified columnar cells and undifferentiated mesenchymal cells. The transitional area between the YS and the primitive intestine was very thin and composed of cells with irregular shapes, which formed a delicate lumen containing hemangioblasts. In the mesenchyme of the transitional area, there were a considerable number of small vessels containing hemangioblasts. Using Oct4 as a primary antibody, we identified positive cells in the metanephros, primordial gonad, and hepatic parenchyma as well as in YS cells, suggesting that these regions contain populations of pluripotent cells. PMID:23650099

Mançanares, Celina A F; Leiser, Rudolf; Favaron, Phelipe O; Carvalho, Ana F; Oliveira, Vanessa C De; Santos, José M Dos; Ambrósio, Carlos E; Miglino, Maria A

2013-05-07

160

A morphological analysis of the transition between the embryonic primitive intestine and yolk sac in bovine embryos and fetuses.  

UK PubMed Central (United Kingdom)

The yolk sac (YS) is the main source of embryonic nutrition during the period when the placenta has not yet formed. It is also responsible for hematopoiesis because the blood cells develop from it as part of the primitive embryonic circulation. The objective of this study was to characterize the transitional area between the YS and primitive gut using the techniques of light microscopy, transmission electron microscopy, and immunohistochemistry to detect populations of pluripotent cells by labeling with Oct4 antibody. In all investigated embryos, serial sections were made to permit the identification of this small, restricted area. We identified the YS connection with the primitive intestine and found that it is composed of many blood islands, which correspond to the vessels covered by vitelline and mesenchymal cells. We identified large numbers of hemangioblasts inside the vessels. The mesenchymal layer was thin and composed of elongated cells, and the vitelline endodermal membrane was composed of large, mono- or binucleated cells. The epithelium of the primitive intestine comprised stratified columnar cells and undifferentiated mesenchymal cells. The transitional area between the YS and the primitive intestine was very thin and composed of cells with irregular shapes, which formed a delicate lumen containing hemangioblasts. In the mesenchyme of the transitional area, there were a considerable number of small vessels containing hemangioblasts. Using Oct4 as a primary antibody, we identified positive cells in the metanephros, primordial gonad, and hepatic parenchyma as well as in YS cells, suggesting that these regions contain populations of pluripotent cells.

Mançanares CA; Leiser R; Favaron PO; Carvalho AF; Oliveira VC; Santos JM; Ambrósio CE; Miglino MA

2013-07-01

 
 
 
 
161

Characterization of Monocarboxylate Transporter 6: Expression in Human Intestine and Transport of the Antidiabetic Drug Nateglinide.  

UK PubMed Central (United Kingdom)

Monocarboxylate transporter 6, encoded by SLC16A5, is a member of the monocarboxylate transporter (MCT) family. Nateglinide, an oral hypoglycemic agent, quickly reaches the maximal serum concentration after its pre-meal administration. Although the functional existence of uptake systems for nateglinide in intestine has been demonstrated, these transport systems have not yet been identified at the molecular level. The aim of this study was to demonstrate the localization of MCT6 in the human small intestine, and characterize the transport properties of nateglinide via MCT6. Immunohistochemical analysis of human small intestine revealed that anti-MCT6 antiserum stained the luminal side of the epithelial cells. When expressed in Xenopus laevis oocytes, MCT6-mediated uptake of [(14)C]nateglinide was sensitive to extracellular pH- and membrane potential. Furthermore, the Kt value of nateglinide (45.9 ?M) for MCT6 was lower than those previously reported in Caco-2 cell and rat intestinal brush-border membrane vesicles. In addition, probenecid, fluorescein, valproic acid, and salicylic acid, which are inhibitors of nateglinide uptake in Caco-2 cells and rat intestine, did not inhibit the uptake of nateglinide via MCT6. These results suggest that MCT6 may play a role in the intestinal absorption of nateglinide, although other transporters are also likely involved.

Kohyama N; Shiokawa H; Ohbayashi M; Kobayashi Y; Yamamoto T

2013-08-01

162

Fecal transplant: a safe and sustainable clinical therapy for restoring intestinal microbial balance in human disease?  

UK PubMed Central (United Kingdom)

Recent studies have suggested an association between intestinal microbiota composition and human disease, however causality remains to be proven. With hindsight, the application of fecal transplantation (FMT) does indeed suggest a causal relation between interfering with gut microbiota composition and a resultant cure of several disease states. In this review, we aim to show the available evidence regarding the involvement of intestinal microbiota and human (autoimmune) disease. Moreover, we refer to (mostly case report) studies showing beneficial or adverse effects of fecal transplantation on clinical outcomes in some of these disease states. If these findings can be substantiated in larger randomized controlled double blind trials also implementing gut microbiota composition before and after intervention, fecal transplantation might provide us with novel insights into causally related intestinal microbiota, that might be serve as future diagnostic and treatment targets in human disease.

Vrieze A; de Groot PF; Kootte RS; Knaapen M; van Nood E; Nieuwdorp M

2013-02-01

163

Contribution of the intestinal microbiota to human health: from birth to 100 years of age.  

UK PubMed Central (United Kingdom)

Our intestinal tract is colonized since birth by multiple microbial species that show a characteristic succession in time. Notably the establishment of the microbiota in early life is important as it appears to impact later health. While apparently stable in healthy adults, the intestinal microbiota is changing significantly during aging. After 100 years of symbiosis marked changes have been observed that may relate to an increased level of intestinal inflammation. There is considerable interest in the microbiota in health and disease as it may provide functional biomarkers, the possibility to differentiate subjects, and avenues for interventions. This chapter reviews the present state of the art on the research to investigate the contribution of the intestinal microbiota to human health. Specific attention will be given to the healthy microbiota and aberrations due to disturbances such as celiac disease, irritable bowel syndrome, inflammatory bowel disease, obesity and diabetes, and non-alcoholic fatty liver disease.

Cheng J; Palva AM; de Vos WM; Satokari R

2013-01-01

164

Comprehensive postmortem analyses of intestinal microbiota changes and bacterial translocation in human flora associated mice.  

UK PubMed Central (United Kingdom)

BACKGROUND: Postmortem microbiological examinations are performed in forensic and medical pathology for defining uncertain causes of deaths and for screening of deceased tissue donors. Interpretation of bacteriological data, however, is hampered by false-positive results due to agonal spread of microorganisms, postmortem bacterial translocation, and environmental contamination. METHODOLOGY/PRINCIPAL FINDINGS: We performed a kinetic survey of naturally occurring postmortem gut flora changes in the small and large intestines of conventional and gnotobiotic mice associated with a human microbiota (hfa) applying cultural and molecular methods. Sacrificed mice were kept under ambient conditions for up to 72 hours postmortem. Intestinal microbiota changes were most pronounced in the ileal lumen where enterobacteria and enterococci increased by 3-5 orders of magnitude in conventional and hfa mice. Interestingly, comparable intestinal overgrowth was shown in acute and chronic intestinal inflammation in mice and men. In hfa mice, ileal overgrowth with enterococci and enterobacteria started 3 and 24 hours postmortem, respectively. Strikingly, intestinal bacteria translocated to extra-intestinal compartments such as mesenteric lymphnodes, spleen, liver, kidney, and cardiac blood as early as 5 min after death. Furthermore, intestinal tissue destruction was characterized by increased numbers of apoptotic cells and neutrophils within 3 hours postmortem, whereas counts of proliferative cells as well as T- and B-lymphocytes and regulatory T-cells decreased between 3 and 12 hours postmortem. CONCLUSIONS/SIGNIFICANCE: We conclude that kinetics of ileal overgrowth with enterobacteria and enterococci in hfa mice can be used as an indicator for compromized intestinal functionality and for more precisely defining the time point of death under defined ambient conditions. The rapid translocation of intestinal bacteria starting within a few minutes after death will help to distinguish between relevant bacteria and secondary contaminants thus providing important informations for routine applications and future studies in applied microbiology, forensic pathology, and criminal medicine.

Heimesaat MM; Boelke S; Fischer A; Haag LM; Loddenkemper C; Kühl AA; Göbel UB; Bereswill S

2012-01-01

165

Genetic diversity of bile salt hydrolases among human intestinal bifidobacteria.  

Science.gov (United States)

This study analyzes the application of degenerative primers for the screening of bile salt hydrolase-encoding genes (bsh) in various intestinal bifidobacteria. In the first stage, the design and evaluation of the universal PCR primers for amplifying the partial coding sequence of bile salt hydrolase in bifidobacteria were performed. The amplified bsh gene fragments were sequenced and the obtained sequences were compared to the bsh genes present in GenBank. The determined results showed the utility of the designed PCR primers for the amplification of partial gene encoding bile salt hydrolase in different intestinal bifidobacteria. Moreover, sequence analysis revealed that bile salt hydrolase-encoding genes may be used as valuable molecular markers for phylogenetic studies and identification of even closely related members of the genus Bifidobacterium. PMID:23591474

Jarocki, Piotr; Targo?ski, Zdzis?aw

2013-04-17

166

Fermentation in the human large intestine: its physiologic consequences and the potential contribution of prebiotics.  

Science.gov (United States)

The human large intestine harbors a complex microbiota containing many hundreds of different bacterial species. Although structure/function relationships between different components of the microbiota are unclear, this complex multicellular entity plays an important role in maintaining homeostasis in the body. Many of the physiologic properties of the microbiota can be attributed to fermentation and the production of short-chain fatty acids (SCFAs), particularly acetate, propionate, and butyrate. In healthy people, fermentation processes are largely controlled by the amounts and different types of substrate, particularly complex carbohydrates that are accessible to bacteria in the colonic ecosystem. However, other factors impact on bacterial metabolism in the large gut, including large bowel transit time, the availability of inorganic terminal electron acceptors, such as nitrate and sulfate, and gut pH. They all affect the types and levels of SCFA that can be formed by the microbiota. This is important because to a large extent, acetate, propionate, and butyrate have varying physiologic effects in different body tissues. Prebiotics such as galactooligosaccharides together with inulins and their fructooligosaccharide derivatives have been shown to modify the species composition of the colonic microbiota, and in various degrees, to manifest several health-promoting properties related to enhanced mineral absorption, laxation, potential anticancer properties, lipid metabolism, and anti-inflammatory and other immune effects, including atopic disease. Many of these phenomena can be linked to their digestion and SCFA production by bacteria in the large gut. PMID:21992950

Macfarlane, George T; Macfarlane, Sandra

2011-11-01

167

Fermentation in the human large intestine: its physiologic consequences and the potential contribution of prebiotics.  

UK PubMed Central (United Kingdom)

The human large intestine harbors a complex microbiota containing many hundreds of different bacterial species. Although structure/function relationships between different components of the microbiota are unclear, this complex multicellular entity plays an important role in maintaining homeostasis in the body. Many of the physiologic properties of the microbiota can be attributed to fermentation and the production of short-chain fatty acids (SCFAs), particularly acetate, propionate, and butyrate. In healthy people, fermentation processes are largely controlled by the amounts and different types of substrate, particularly complex carbohydrates that are accessible to bacteria in the colonic ecosystem. However, other factors impact on bacterial metabolism in the large gut, including large bowel transit time, the availability of inorganic terminal electron acceptors, such as nitrate and sulfate, and gut pH. They all affect the types and levels of SCFA that can be formed by the microbiota. This is important because to a large extent, acetate, propionate, and butyrate have varying physiologic effects in different body tissues. Prebiotics such as galactooligosaccharides together with inulins and their fructooligosaccharide derivatives have been shown to modify the species composition of the colonic microbiota, and in various degrees, to manifest several health-promoting properties related to enhanced mineral absorption, laxation, potential anticancer properties, lipid metabolism, and anti-inflammatory and other immune effects, including atopic disease. Many of these phenomena can be linked to their digestion and SCFA production by bacteria in the large gut.

Macfarlane GT; Macfarlane S

2011-11-01

168

Scintigraphic determination of small intestinal transit time of water in man  

Energy Technology Data Exchange (ETDEWEB)

A method utilizing a lactulose solution to measure small intestinal transit time (SITT) has been previously reported. Lactulose is a non-absorbable sugar and is known to increase SITT. In order to determine the extent to which lactulose accelerates SITT, a group of 4 normal male volunteers were studied after the ingestion of 150cc of water to which 100 uCi of 111-In was added. To provide adequate caloric intake, as occurs physiologically, the water was drunk while ingesting a solid meal. The subject was then placed supine under a 15 inch gamma camera. Data were collected and stored in a computer at one frame every 3 minute for 240 minutes. If activity was not present in the cecal region by this time, the subject was allowed to move about for 15 minutes and then repositioned under the gamma camera. Data were first viewed in a movie format. Regions of interest were selected over the cecum and ascending colon. The time of first appearance of radioactivity in the region of the cecum was taken as the SITT. Each subject was studied on three separate occasions. The mean (+- SEM) SITT for each of the separate studies was 248 +- 58 min., 240 +- 47 min. and 232 +- 54 min. respectively (pless than or equal toNS). Two previously studied groups of normal volunteers had a mean SITT of approximately 80 minutes. Water appears to have a significantly slower SITT when ingested with a solid meal when compared to lactulose. Clinically, the potential to use water as a test for SITT would not seem to be as attractive or practical as using lactulose as the test substance.

Prokop, E.K.; Caride, V.J.; Marano, A.R.; McCallum, R.

1984-01-01

169

Robust antiviral responses to enterovirus 71 infection in human intestinal epithelial cells.  

Science.gov (United States)

Enterovirus 71 (EV71) is a single-stranded RNA virus that belongs to Picornaviridae family. It causes the hand-foot-and-mouth disease and fatal neurological diseases in young children and infants. The mechanism of EV71 pathogenesis remains obscure. The intestinal tract is the initial site of EV71 replication, but no or only mild gastrointestinal symptoms are observed clinically, suggesting that host immune responses of the intestinal epithelium to EV71 may be unique, which, however, remains rarely investigated. In this study, we showed that human intestinal epithelial cells HT-29 were susceptible to EV71, and the infected cells exhibited cytopathic effects (CPEs) and were prone to apoptosis. TLR-7 and TLR-8 were induced significantly post infection and may be pivotal in the induction of IFN-? and host innate immune responses against EV71. Among proinflammatory responses in EV71-infected intestinal epithelial cells, IL-6, CCL5, and IP10 were up-regulated and may play a key role in intestinal pathogenicity. We examined extrinsic and intrinsic apoptotic pathways and found that both were activated in EV71 infection. The mitochondria-mediated intrinsic pathway may also be activated through Bid cleaved by active caspase-8. Robust induction of IFN-? in human intestinal epithelial cells contradicts the finding that IFN induction was suppressed in other types of the cells, suggesting that mild gastrointestinal symptoms may be the result of sufficient local antiviral inductions. Our study has demonstrated a unique way of antiviral responses in human gut different from other tissue cells in response to EV71, which may account for mild symptoms in intestinal tract. This finding will broaden our understanding of host defense mechanism and the pathogenesis of EV71 infection. PMID:23685430

Chi, Chuanzhen; Sun, Qiyu; Wang, Shuai; Zhang, Zerui; Li, Xue; Cardona, Carol J; Jin, Yu; Xing, Zheng

2013-05-16

170

Robust antiviral responses to enterovirus 71 infection in human intestinal epithelial cells.  

UK PubMed Central (United Kingdom)

Enterovirus 71 (EV71) is a single-stranded RNA virus that belongs to Picornaviridae family. It causes the hand-foot-and-mouth disease and fatal neurological diseases in young children and infants. The mechanism of EV71 pathogenesis remains obscure. The intestinal tract is the initial site of EV71 replication, but no or only mild gastrointestinal symptoms are observed clinically, suggesting that host immune responses of the intestinal epithelium to EV71 may be unique, which, however, remains rarely investigated. In this study, we showed that human intestinal epithelial cells HT-29 were susceptible to EV71, and the infected cells exhibited cytopathic effects (CPEs) and were prone to apoptosis. TLR-7 and TLR-8 were induced significantly post infection and may be pivotal in the induction of IFN-? and host innate immune responses against EV71. Among proinflammatory responses in EV71-infected intestinal epithelial cells, IL-6, CCL5, and IP10 were up-regulated and may play a key role in intestinal pathogenicity. We examined extrinsic and intrinsic apoptotic pathways and found that both were activated in EV71 infection. The mitochondria-mediated intrinsic pathway may also be activated through Bid cleaved by active caspase-8. Robust induction of IFN-? in human intestinal epithelial cells contradicts the finding that IFN induction was suppressed in other types of the cells, suggesting that mild gastrointestinal symptoms may be the result of sufficient local antiviral inductions. Our study has demonstrated a unique way of antiviral responses in human gut different from other tissue cells in response to EV71, which may account for mild symptoms in intestinal tract. This finding will broaden our understanding of host defense mechanism and the pathogenesis of EV71 infection.

Chi C; Sun Q; Wang S; Zhang Z; Li X; Cardona CJ; Jin Y; Xing Z

2013-09-01

171

The effect of Saccharomyces boulardii on Candida albicans-infected human intestinal cell lines Caco-2 and Intestin 407.  

Science.gov (United States)

Saccharomyces boulardii is a probiotic strain that confers many benefits to human enterocolopathies and is used against a number of enteric pathogens. Candida albicans is an opportunistic pathogen that causes intestinal infections in immunocompromised patients, and after translocation into the bloodstream, is responsible for serious systemic candidiasis. In this study, we investigated the influence of S. boulardii cells and its culture extract on C. albicans adhesion to Caco-2 and Intestin 407 cell lines. We also tested the proinflammatory IL-1beta, IL-6 and IL-8 cytokine expression by C. albicans-infected Caco-2 cells, using real-time RT-PCR. We found that both S. boulardii and its extract significantly inhibited C. albicans adhesion to epithelial cell lines. The IL-8 gene expression by C. albicans-infected Caco-2 cells was suppressed by the addition of S. boulardii extract. Our results indicate that S. boulardii affects C. albicans adhesion and reduces cytokine-mediated inflammatory host response. PMID:20629753

Murzyn, Anna; Krasowska, Anna; Augustyniak, Daria; Majkowska-Skrobek, Grazyna; ?ukaszewicz, Marcin; Dziadkowiec, Dorota

2010-06-16

172

A review of drug solubility in human intestinal fluids: Implications for the prediction of oral absorption.  

UK PubMed Central (United Kingdom)

The purpose of this paper is to collate all recently published solubility data of orally administered drugs in human intestinal fluids (HIF) that were aspirated from the upper small intestine (duodenum and jejunum). The data set comprises in total 102 solubility values in fasted state HIF and 37 solubility values in fed state HIF, covering 59 different drugs. Despite differences in the protocol for HIF sampling and subsequent handling, this summary of HIF solubilities provides a critical reference data set to judge the value of simulated media for intestinal solubility estimation. In this regard, the review includes correlations between the reported solubilizing capacity of HIF and fasted or fed state simulated intestinal fluid (FaSSIF/FeSSIF). Correlating with HIF solubilities enables the optimal use of solubility measurements in simulated biorelevant media to obtain accurate estimates of intestinal solubility during drug development. Considering the fraction of poorly soluble new molecular entities in contemporary drug discovery, adequate prediction of intestinal solubility is critical for efficient lead optimization, early candidate profiling, and further development.

Augustijns P; Wuyts B; Hens B; Annaert P; Butler J; Brouwers J

2013-08-01

173

High-throughput analysis of the impact of antibiotics on the human intestinal microbiota composition.  

UK PubMed Central (United Kingdom)

Antibiotic treatments can lead to a disruption of the human microbiota. In this in-vitro study, the impact of antibiotics on adult intestinal microbiota was monitored in a new high-throughput approach: a fermentation screening-platform was coupled with a phylogenetic microarray analysis (Intestinal-chip). Fecal inoculum from healthy adults was exposed in a fermentation screening-platform to seven widely-used antibiotics during 24h in-vitro fermentation and the microbiota composition was subsequently determined with the Intestinal-chip. Phylogenetic microarray analysis was first verified to be reliable with respect to variations in the total number of bacteria and presence of dead (or inactive) cells. Intestinal-chip analysis was then used to identify and compare shifts in the intestinal microbial composition after exposure to low and high dose (1?gml(-1) and 10?gml(-1)) antibiotics. Observed shifts on family, genus and species level were both antibiotic and dose dependent. Stronger changes in microbiota composition were observed with higher doses. Shifts mainly concerned the bacterial groups Bacteroides, Bifidobacterium, Clostridium, Enterobacteriaceae, and Lactobacillus. Within bacterial groups, specific antibiotics were shown to differentially impact related species. The combination of the in-vitro fermentation screening platform with the phylogenetic microarray read-outs has shown to be reliable to simultaneously analyze the effects of several antibiotics on intestinal microbiota.

Ladirat SE; Schols HA; Nauta A; Schoterman MH; Keijser BJ; Montijn RC; Gruppen H; Schuren FH

2013-03-01

174

The effect of tacrolimus (FK506) on intestinal barrier function and cellular energy production in humans.  

UK PubMed Central (United Kingdom)

BACKGROUND & AIMS: The maintenance of the intestinal mucosal barrier may be energy dependent. Tacrolimus is a potent immunosuppressive drug that decreases mitochondrial adenosine triphosphate production and increases intestinal permeability in animals. METHODS: Twelve liver graft recipients receiving tacrolimus, 9 healthy volunteers, and 5 liver graft recipients not receiving immunosuppression underwent a combined absorption-permeability-mitochondrial function test using 5 g lactulose, 1 g L-rhamnose, 0.5 g D-xylose, 0.2 g 3-O-methyl-D-glucose, 1 mg/kg 2-keto[1-13C]isocaproic acid ([13C]KICA), and 20 mg/kg L-leucine. The respiratory quotient and resting energy expenditure were measured by indirect calorimetry. Tacrolimus pharmacokinetic profiles and levels of endotoxin and IgM and IgG endotoxin core antibodies were determined. RESULTS: Tacrolimus inhibited the decarboxylation of [13C]KICA, the resting energy expenditure, and the respiratory quotient in an exposure-dependent manner, suggesting an inhibition of mitochondrial respiration. Tacrolimus inhibited intestinal absorptive capacity in an exposure-dependent manner. Tacrolimus-treated patients had an increased intestinal permeability and significantly higher endotoxin levels compared with healthy volunteers. CONCLUSIONS: Tacrolimus inhibits cellular energy production in humans at clinically relevant doses. This is associated with an increased intestinal permeability, endotoxemia, and an impaired intestinal absorptive capacity.

Gabe SM; Bjarnason I; Tolou-Ghamari Z; Tredger JM; Johnson PG; Barclay GR; Williams R; Silk DB

1998-07-01

175

[Establishment of nude mice liver metastatic model of human primary malignant melanoma of the small intestine].  

UK PubMed Central (United Kingdom)

OBJECTIVE: To provide ideal animal models for exploring pathogenesis and experimental therapy of primary malignant melanoma of the small intestine. METHODS: The histologically intact primary and liver metastatic fragments derived from surgical specimens of one patient with metastatic malignant melanoma of the small intestine were orthotopically implanted in the small intestinal mucous layer of nude mice. The take rate, invasion and liver metastasis were observed. Morphology (light microscopy, electron microscopy), immunophenotype analysis, flow cytometry and karyotype analysis were applied for the original human tumors and the transplanted tumors. RESULTS: The primary and liver metastatic fragments of malignant melanoma of the small intestine were successfully implanted in nude mice. After continuous passages in nude mice,an orthotopic model of human primary malignant melanoma of the small intestine(from the primary focus)in nude mice (termed HSIM-0501) and a liver metastatic model of human primary malignant melanoma of the small intestine (from the liver metastatic focus) in nude mice (termed HSIM-0502) were established. Histological examination of transplanted tumors revealed high-grade melanoma. S-100 protein and HMB45 were positive. Massive melanin granules and melanin complex were seen in cytoplasm of tumor cells.Chromosomal modal number was between 55 and 59. DNA index (DI) was 1.49-1.61, representing heteroploid. HSIM-0501 and HSIM-0502 were maintained for 25 and 27 passages in nude mice respectively. Three hundred and seventeen nude mice were used for transplantation. Both the take rate after transplantation and resuscitation rate of liquid nitrogen cryopreservation were 100%. HSIM-0501 exhibited 46.2% liver metastasis and 36.7% lymph node metastases. In HSIM-0502, both liver and lymph node metastases were 100%.The transplanted tumors autonomically and invasively grew in the small intestines of nude mice and hematogenous metastasis, lymph node metastasis and celiac planting metastasis occurred. CONCLUSION: Two nude mice liver metastatic models of human primary malignant melanoma of the small intestine are successfully established, which provide ideal animal models for the research of pathogenesis,metastasis biology and anti-metastatic experimental therapy of primary malignant melanoma of the small intestine.

Tuo S; Zhang N; Liu QZ

2008-07-01

176

Vitamin B12 absorption following human intestinal bypass surgery.  

UK PubMed Central (United Kingdom)

Adaptation of vitamin B12 absorption by small intestine has been suggested by experimental and clinical studies. Five partial ileal bypass patients and ten jejunoileal bypass patients were studied for adaptation of B12 absorption following surgery. Adaptation of vitamin B12 absorption could not be demonstrated in either group. Few of the patients on an individual basis demonstrated adaptation. Parenteral B12 should be given to all patients who undergo bypass surgery unless evidence of persistent normal B12 absorption has been obtained.

Coyle JJ; Varco RL; Buchwald H

1977-12-01

177

Intestinal pH and gastrointestinal transit profiles in cystic fibrosis patients measured by wireless motility capsule.  

UK PubMed Central (United Kingdom)

BACKGROUND AND AIMS: The effect of the cystic fibrosis transmembrane conductance regulator protein (CFTR) defect in pancreatic insufficient (PI) patients with cystic fibrosis (CF) on the gastrointestinal pH profile is poorly defined. Adequate and efficient neutralization of the gastric acidity in the duodenum is important for nutrient absorption and timely release of pancreatic enzyme replacement therapy (PERT). We utilized a wireless motility capsule (WMC) to study intestinal pH profile and gastrointestinal transit profile in CF subjects. METHODS: WMC studies were done on ten adult CF patients with PI while off acid suppression medication and ten age, gender and BMI matched healthy controls. Mean pH over 1 min increments and area under the pH curve over 5 min increments was calculated for the first hour post gastric emptying. Paired t-test was used to compare means of the pH recordings, transit profiles and analysis of time interval required to reach and maintain pH >5.5 and 6.0. RESULTS: A statistically significant difference was observed between mean pH values during the first 23 min of small bowel transit (p < 0.05). In CF subjects, there was a significant delay in time interval required to reach and sustain pH 5.5 and pH 6.0 (p < 0.001), which is required for PERT dissolution. Only small bowel transit in CF subjects was noted to be significantly delayed (p = 0.004) without a compensatory increase in whole gut transit time. CONCLUSIONS: We have demonstrated a significant delay in the small intestinal transit and a deficient buffering capacity required to neutralize gastric acid in the proximal small bowel of patients with CF.

Gelfond D; Ma C; Semler J; Borowitz D

2013-08-01

178

Activation of AMPK Inhibits Cholera Toxin Stimulated Chloride Secretion in Human and Murine Intestine  

Science.gov (United States)

Increased intestinal chloride secretion through chloride channels, such as the cystic fibrosis transmembrane conductance regulator (CFTR), is one of the major molecular mechanisms underlying enterotoxigenic diarrhea. It has been demonstrated in the past that the intracellular energy sensing kinase, the AMP-activated protein kinase (AMPK), can inhibit CFTR opening. We hypothesized that pharmacological activation of AMPK can abrogate the increased chloride flux through CFTR occurring during cholera toxin (CTX) mediated diarrhea. Chloride efflux was measured in isolated rat colonic crypts using real-time fluorescence imaging. AICAR and metformin were used to activate AMPK in the presence of the secretagogues CTX or forskolin (FSK). In order to substantiate our findings on the whole tissue level, short-circuit current (SCC) was monitored in human and murine colonic mucosa using Ussing chambers. Furthermore, fluid accumulation was measured in excised intestinal loops. CTX and forskolin (FSK) significantly increased chloride efflux in isolated colonic crypts. The increase in chloride efflux could be offset by using the AMPK activators AICAR and metformin. In human and mouse mucosal sheets, CTX and FSK increased SCC. AICAR and metformin inhibited the secretagogue induced rise in SCC, thereby confirming the findings made in isolated crypts. Moreover, AICAR decreased CTX stimulated fluid accumulation in excised intestinal segments. The present study suggests that pharmacological activation of AMPK effectively reduces CTX mediated increases in intestinal chloride secretion, which is a key factor for intestinal water accumulation. AMPK activators may therefore represent a supplemental treatment strategy for acute diarrheal illness.

Hoekstra, Nadia; Collins, Danielle; Collaco, Anne; Baird, Alan W.; Winter, Desmond C.; Ameen, Nadia; Geibel, John P.; Kopic, Sascha

2013-01-01

179

Activation of AMPK inhibits cholera toxin stimulated chloride secretion in human and murine intestine.  

UK PubMed Central (United Kingdom)

Increased intestinal chloride secretion through chloride channels, such as the cystic fibrosis transmembrane conductance regulator (CFTR), is one of the major molecular mechanisms underlying enterotoxigenic diarrhea. It has been demonstrated in the past that the intracellular energy sensing kinase, the AMP-activated protein kinase (AMPK), can inhibit CFTR opening. We hypothesized that pharmacological activation of AMPK can abrogate the increased chloride flux through CFTR occurring during cholera toxin (CTX) mediated diarrhea. Chloride efflux was measured in isolated rat colonic crypts using real-time fluorescence imaging. AICAR and metformin were used to activate AMPK in the presence of the secretagogues CTX or forskolin (FSK). In order to substantiate our findings on the whole tissue level, short-circuit current (SCC) was monitored in human and murine colonic mucosa using Ussing chambers. Furthermore, fluid accumulation was measured in excised intestinal loops. CTX and forskolin (FSK) significantly increased chloride efflux in isolated colonic crypts. The increase in chloride efflux could be offset by using the AMPK activators AICAR and metformin. In human and mouse mucosal sheets, CTX and FSK increased SCC. AICAR and metformin inhibited the secretagogue induced rise in SCC, thereby confirming the findings made in isolated crypts. Moreover, AICAR decreased CTX stimulated fluid accumulation in excised intestinal segments. The present study suggests that pharmacological activation of AMPK effectively reduces CTX mediated increases in intestinal chloride secretion, which is a key factor for intestinal water accumulation. AMPK activators may therefore represent a supplemental treatment strategy for acute diarrheal illness.

Rogers AC; Huetter L; Hoekstra N; Collins D; Collaco A; Baird AW; Winter DC; Ameen N; Geibel JP; Kopic S

2013-01-01

180

Activation of AMPK inhibits cholera toxin stimulated chloride secretion in human and murine intestine.  

Science.gov (United States)

Increased intestinal chloride secretion through chloride channels, such as the cystic fibrosis transmembrane conductance regulator (CFTR), is one of the major molecular mechanisms underlying enterotoxigenic diarrhea. It has been demonstrated in the past that the intracellular energy sensing kinase, the AMP-activated protein kinase (AMPK), can inhibit CFTR opening. We hypothesized that pharmacological activation of AMPK can abrogate the increased chloride flux through CFTR occurring during cholera toxin (CTX) mediated diarrhea. Chloride efflux was measured in isolated rat colonic crypts using real-time fluorescence imaging. AICAR and metformin were used to activate AMPK in the presence of the secretagogues CTX or forskolin (FSK). In order to substantiate our findings on the whole tissue level, short-circuit current (SCC) was monitored in human and murine colonic mucosa using Ussing chambers. Furthermore, fluid accumulation was measured in excised intestinal loops. CTX and forskolin (FSK) significantly increased chloride efflux in isolated colonic crypts. The increase in chloride efflux could be offset by using the AMPK activators AICAR and metformin. In human and mouse mucosal sheets, CTX and FSK increased SCC. AICAR and metformin inhibited the secretagogue induced rise in SCC, thereby confirming the findings made in isolated crypts. Moreover, AICAR decreased CTX stimulated fluid accumulation in excised intestinal segments. The present study suggests that pharmacological activation of AMPK effectively reduces CTX mediated increases in intestinal chloride secretion, which is a key factor for intestinal water accumulation. AMPK activators may therefore represent a supplemental treatment strategy for acute diarrheal illness. PMID:23935921

Rogers, Ailín C; Huetter, Lisa; Hoekstra, Nadia; Collins, Danielle; Collaco, Anne; Baird, Alan W; Winter, Desmond C; Ameen, Nadia; Geibel, John P; Kopic, Sascha

2013-07-30

 
 
 
 
181

In vitro intestinal and hepatic metabolism of Di(2-ethylhexyl) phthalate (DEHP) in human and rat.  

Science.gov (United States)

Species and organ differences in the intrinsic clearance and the enzymes involved in the metabolism of DEHP were examined in subcellular fractions of the intestine and liver as well as by recombinant cytochrome P450 (CYP) isoforms of human and rat. Estimated clearance (CLint) of DEHP via esterase-mediated pathway in human intestine was 2.4-fold greater than that in human liver while its value in rat intestine was 1.7-fold less than that in rat liver. Ranks of CLint for CYP-mediated oxidation/dealkylation of MEHP were human liver>rat liver>human intestine>rat intestine. Estimates of CLint for the production of mono(2-ethyl-5-hydroxyhexyl) phthalate and mono(2-ethyl-5-oxohexyl) phthalate by human CYP2C9 1 were 4.2- and 2.6-fold greater than those by rat CYP2C6, respectively. Total CLint via hCYP2C9 3-mediated oxidation was 1.9- and 2.6-fold less than those by hCYP2C9 2 and 2C9 1, respectively. Estimated CLint for phthalic acid production by hCYP3A4 was 24.5 ?L nmol CYP(-1)min(-1) while it was continuously produced by rCYP2C6 and 3A2 via passive mechanism. These species/organ differences in major metabolic pathway and CYP isoforms should be considered for appraisal of the potential adverse health effects of DEHP. PMID:23545481

Choi, Kyoungju; Joo, Hyun; Campbell, Jerry L; Andersen, Melvin E; Clewell, Harvey J

2013-03-29

182

In vitro intestinal and hepatic metabolism of Di(2-ethylhexyl) phthalate (DEHP) in human and rat.  

UK PubMed Central (United Kingdom)

Species and organ differences in the intrinsic clearance and the enzymes involved in the metabolism of DEHP were examined in subcellular fractions of the intestine and liver as well as by recombinant cytochrome P450 (CYP) isoforms of human and rat. Estimated clearance (CLint) of DEHP via esterase-mediated pathway in human intestine was 2.4-fold greater than that in human liver while its value in rat intestine was 1.7-fold less than that in rat liver. Ranks of CLint for CYP-mediated oxidation/dealkylation of MEHP were human liver>rat liver>human intestine>rat intestine. Estimates of CLint for the production of mono(2-ethyl-5-hydroxyhexyl) phthalate and mono(2-ethyl-5-oxohexyl) phthalate by human CYP2C9 1 were 4.2- and 2.6-fold greater than those by rat CYP2C6, respectively. Total CLint via hCYP2C9 3-mediated oxidation was 1.9- and 2.6-fold less than those by hCYP2C9 2 and 2C9 1, respectively. Estimated CLint for phthalic acid production by hCYP3A4 was 24.5 ?L nmol CYP(-1)min(-1) while it was continuously produced by rCYP2C6 and 3A2 via passive mechanism. These species/organ differences in major metabolic pathway and CYP isoforms should be considered for appraisal of the potential adverse health effects of DEHP.

Choi K; Joo H; Campbell JL Jr; Andersen ME; Clewell HJ 3rd

2013-08-01

183

Extrathymic T cell differentiation in the human intestine early in life.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

It is clear from experimental studies in mice that T cell maturation can occur outside the thymus, especially in the intestine. There is little sound evidence so far that extrathymic T cell maturation occurs to any significant extent in human gut, and, postnatally, there is abundant evidence that th...

Howie, D; Spencer, J; DeLord, D; Pitzalis, C; Wathen, NC; Dogan, A; Akbar, A; MacDonald, TT

184

Influence of Exposure Time on Gene Expression by Human Intestinal Epithelial Cells Exposed to Lactobacillus acidophilus  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Analysis of global temporal gene expression by human intestinal cells when exposed to Lactobacillus acidophilus revealed induction of immune-related pathways and NF-?B target genes after a 1-h exposure, compared to a 4- or 8-h exposure. Additionally, an L. acidophilus derivative expressing covalentl...

O'Flaherty, Sarah; Klaenhammer, Todd R.

185

Consensus hologram QSAR modeling for the prediction of human intestinal absorption.  

UK PubMed Central (United Kingdom)

Consistent in silico models for ADME properties are useful tools in early drug discovery. Here, we report the hologram QSAR modeling of human intestinal absorption using a dataset of 638 compounds with experimental data associated. The final validated models are consistent and robust for the consensus prediction of this important pharmacokinetic property and are suitable for virtual screening applications.

Moda TL; Andricopulo AD

2012-04-01

186

The Mucin Degrader Akkermansia muciniphila Is an Abundant Resident of the Human Intestinal Tract? †  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A 16S rRNA-targeted probe, MUC-1437, was designed and validated in order to determine the presence and numbers of cells of Akkermansia muciniphila, a mucin degrader, in the human intestinal tract. As determined by fluorescent in situ hybridization, A. muciniphila accounted more than 1% of the total ...

Derrien, Muriel; Collado, M. Carmen; Ben-Amor, Kaouther; Salminen, Seppo; de Vos, Willem M.

187

Akkermansia muciniphila gen. nov., sp. nov., a human intestinal mucin-degrading bacterium  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The diversity of mucin-degrading bacteria in the human intestine was investigated by combining culture and 16S rRNA-dependent approaches. A dominant bacterium, strain MucT, was isolated by dilution to extinction of faeces in anaerobic medium containing gastric mucin as the sole carbon and nitrogen s...

Derrien, M.M.N.; Vaughan, E.E.; Plugge, C.M.; Vos, W.M., de

188

The mucin degrader Akkermansia muciniphila is an abundant resident of the human intestinal tract  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A 16S rRNA-targeted probe, MUC-1437, was designed and validated in order to determine the presence and numbers of cells of Akkermansia muciniphila, a mucin degrader, in the human intestinal tract. As determined by fluorescent in situ hybridization, A. muciniphila accounted more than 1% of the total ...

Derrien, M.M.N.; Collado, M.C.; Ben-Amor, K.; Salminen, S.; Vos, W.M., de

189

Ultrasound elasticity imaging for detecting intestinal fibrosis and inflammation in rats and humans with Crohn's disease.  

UK PubMed Central (United Kingdom)

BACKGROUND: Intestinal fibrosis causes many complications of Crohn's disease (CD). Available biomarkers and imaging modalities lack sufficient accuracy to distinguish intestinal inflammation from fibrosis. Transcutaneous ultrasound elasticity imaging (UEI) is a promising, noninvasive approach for measuring tissue mechanical properties. We hypothesized that UEI could differentiate inflammatory from fibrotic bowel wall changes in both animal models of colitis and humans with CD. METHODS: Female Lewis rats underwent weekly trinitrobenzene sulfonic acid enemas yielding models of acute inflammatory colitis (n = 5) and chronic intestinal fibrosis (n = 6). UEI scanning used a novel speckle-tracking algorithm to estimate tissue strain. Resected bowel segments were evaluated for evidence of inflammation and fibrosis. Seven consecutive patients with stenotic CD were studied with UEI and their resected stenotic and normal bowel segments were evaluated by ex vivo elastometry and histopathology. RESULTS: Transcutaneous UEI normalized strain was able to differentiate acutely inflamed (-2.07) versus chronic fibrotic (-1.10) colon in rat models of inflammatory bowel disease (IBD; P = .037). Transcutaneous UEI normalized strain also differentiated stenotic (-0.87) versus adjacent normal small bowel (-1.99) in human CD (P = .0008), and this measurement also correlated well with ex vivo elastometry (r = -0.81). CONCLUSIONS: UEI can differentiate inflammatory from fibrotic intestine in rat models of IBD and can differentiate between fibrotic and unaffected intestine in a pilot study in humans with CD. UEI represents a novel technology with potential to become a new objective measure of progression of intestinal fibrosis. Prospective clinical studies in CD are needed.

Stidham RW; Xu J; Johnson LA; Kim K; Moons DS; McKenna BJ; Rubin JM; Higgins PD

2011-09-01

190

Intestinal transport of manganese from human milk, bovine milk and infant formula in rats  

Energy Technology Data Exchange (ETDEWEB)

The transport of manganese from extrinsically labeled human milk, bovine milk and infant formula was studied by the everted intestinal sac method. Tissue/mucosal flux data indicated that transport of manganese into the intestinal tissue was significantly greater with bovine milk and formula than from human milk. Similarly, the total flux of manganese from the mucosal to serosal surface was less when human milk was used. Smaller molecular weight manganese binding ligands isolated from the milk samples enhanced the mucosal to tissue movement of manganese as contrasted to the higher molecular weight manganese binding ligands. Most significantly the data suggest that the transport and uptake of manganese is less in the presence of human milk and its isolated manganese fractions than it is in bovine milk or infant formula. 15 references, 3 tables.

Chan, W.Y.; Bates, J.M. Jr.; Rennert, O.M.; Mahmood, A.; Torres-Pinedo, R.

1984-12-10

191

Fast pouch emptying, delayed small intestinal transit, and exaggerated gut hormone responses after Roux-en-Y gastric bypass.  

UK PubMed Central (United Kingdom)

BACKGROUND: Roux-en-Y gastric bypass (RYGB) causes extensive changes in gastrointestinal anatomy and leads to reduced appetite and large weight loss, which partly is due to an exaggerated release of anorexigenic gut hormones. METHODS: To examine whether the altered passage of foods through the gastrointestinal tract after RYGB could be responsible for the changes in gut hormone release, we studied gastrointestinal motility with a scintigraphic technique as well as the secretion of the gut hormones glucagon-like peptide (GLP)-1 and peptide YY3-36 (PYY3-36 ) in 17 patients>1 year after RYGB and in nine healthy control subjects. KEY RESULTS: At meal completion, a smaller fraction of liquid and solid radiolabeled marker was retained in the pouch of RYGB patients than in the stomach of control subjects (P = 0.002 and P < 0.001, respectively). Accordingly, pouch emptying in patients was faster than gastric emptying in control subjects (P < 0.001 and P = 0.004, respectively liquid and solid markers). For the solid marker, small intestinal transit was slower in patients than control subjects (P = 0.034). Colonic transit rate did not differ between the groups. GLP-1 and PYY3-36 secretion was increased in patients compared to control subjects and fast pouch emptying of the liquid marker was associated with high gut hormone secretion. CONCLUSIONS & INFERENCES: After RYGB, the bulk of foods pass without hindrance into the small intestine, while the small intestinal transit is prolonged. The rapid exposure of the gut epithelium contributes to the exaggerated release of GLP-1 and PYY3-36 after RYGB.

Dirksen C; Damgaard M; Bojsen-Møller KN; Jørgensen NB; Kielgast U; Jacobsen SH; Naver LS; Worm D; Holst JJ; Madsbad S; Hansen DL; Madsen JL

2013-04-01

192

Exploring the diversity of the bifidobacterial population in the human intestinal tract.  

UK PubMed Central (United Kingdom)

Although the health-promoting roles of bifidobacteria are widely accepted, the diversity of bifidobacteria among the human intestinal microbiota is still poorly understood. We performed a census of bifidobacterial populations from human intestinal mucosal and fecal samples by plating them on selective medium, coupled with molecular analysis of selected rRNA gene sequences (16S rRNA gene and internally transcribed spacer [ITS] 16S-23S spacer sequences) of isolated colonies. A total of 900 isolates were collected, of which 704 were shown to belong to bifidobacteria. Analyses showed that the culturable bifidobacterial population from intestinal and fecal samples include six main phylogenetic taxa, i.e., Bifidobacterium longum, Bifidobacterium pseudocatenulatum, Bifidobacterium adolescentis, Bifidobacterium pseudolongum, Bifidobacterium breve, and Bifidobacterium bifidum, and two species mostly detected in fecal samples, i.e., Bifidobacterium dentium and Bifidobacterium animalis subp. lactis. Analysis of bifidobacterial distribution based on age of the subject revealed that certain identified bifidobacterial species were exclusively present in the adult human gut microbiota whereas others were found to be widely distributed. We encountered significant intersubject variability and composition differences between fecal and mucosa-adherent bifidobacterial communities. In contrast, a modest diversification of bifidobacterial populations was noticed between different intestinal regions within the same individual (intrasubject variability). Notably, a small number of bifidobacterial isolates were shown to display a wide ecological distribution, thus suggesting that they possess a broad colonization capacity.

Turroni F; Foroni E; Pizzetti P; Giubellini V; Ribbera A; Merusi P; Cagnasso P; Bizzarri B; de'Angelis GL; Shanahan F; van Sinderen D; Ventura M

2009-03-01

193

Interaction of Campylobacter spp. and human probiotics in chicken intestinal mucus.  

Science.gov (United States)

Campylobacter is the most common cause of bacterial food-borne diarrhoeal disease throughout the world. The principal risk of human contamination is handling and consumption of contaminated poultry meat. To colonize poultry, Campylobacter adheres to and persists in the mucus layer that covers the intestinal epithelium. Inhibiting adhesion to the mucus could prevent colonization of the intestine. The aim of this study was to investigate in vitro the protective effect of defined commercial human probiotic strains on the adhesion of Campylobacter spp. to chicken intestinal mucus, in a search for alternatives to antibiotics to control this food-borne pathogen. The probiotic strains Lactobacillus rhamnosus GG and Propionibacterium freudenreichii ssp. shermanii JS and a starter culture strain Lactococcus lactis ssp. lactis adhered well to chicken intestinal mucus and were able to reduce the binding of Campylobacter spp. when the mucus was colonized with the probiotic strain before contacting the pathogen. Human-intended probiotics could be useful as prophylactics in poultry feeding for controlling Campylobacter spp. colonization. PMID:22672405

Ganan, M; Martinez-Rodriguez, A J; Carrascosa, A V; Vesterlund, S; Salminen, S; Satokari, R

2012-06-06

194

Interaction of Campylobacter spp. and human probiotics in chicken intestinal mucus.  

UK PubMed Central (United Kingdom)

Campylobacter is the most common cause of bacterial food-borne diarrhoeal disease throughout the world. The principal risk of human contamination is handling and consumption of contaminated poultry meat. To colonize poultry, Campylobacter adheres to and persists in the mucus layer that covers the intestinal epithelium. Inhibiting adhesion to the mucus could prevent colonization of the intestine. The aim of this study was to investigate in vitro the protective effect of defined commercial human probiotic strains on the adhesion of Campylobacter spp. to chicken intestinal mucus, in a search for alternatives to antibiotics to control this food-borne pathogen. The probiotic strains Lactobacillus rhamnosus GG and Propionibacterium freudenreichii ssp. shermanii JS and a starter culture strain Lactococcus lactis ssp. lactis adhered well to chicken intestinal mucus and were able to reduce the binding of Campylobacter spp. when the mucus was colonized with the probiotic strain before contacting the pathogen. Human-intended probiotics could be useful as prophylactics in poultry feeding for controlling Campylobacter spp. colonization.

Ganan M; Martinez-Rodriguez AJ; Carrascosa AV; Vesterlund S; Salminen S; Satokari R

2013-03-01

195

Unique insights into the intestinal absorption, transit, and subsequent biodistribution of polymer-derived microspheres.  

Science.gov (United States)

Polymeric microspheres (MSs) have received attention for their potential to improve the delivery of drugs with poor oral bioavailability. Although MSs can be absorbed into the absorptive epithelium of the small intestine, little is known about the physiologic mechanisms that are responsible for their cellular trafficking. In these experiments, nonbiodegradable polystyrene MSs (diameter range: 500 nm to 5 µm) were delivered locally to the jejunum or ileum or by oral administration to young male rats. Following administration, MSs were taken up rapidly (?5 min) by the small intestine and were detected by transmission electron microscopy and confocal laser scanning microscopy. Gel permeation chromatography confirmed that polymer was present in all tissue samples, including the brain. These results confirm that MSs (diameter range: 500 nm to 5 µm) were absorbed by the small intestine and distributed throughout the rat. After delivering MSs to the jejunum or ileum, high concentrations of polystyrene were detected in the liver, kidneys, and lungs. The pharmacologic inhibitors chlorpromazine, phorbol 12-myristate 13-acetate, and cytochalasin D caused a reduction in the total number of MSs absorbed in the jejunum and ileum, demonstrating that nonphagocytic processes (including endocytosis) direct the uptake of MSs in the small intestine. These results challenge the convention that phagocytic cells such as the microfold cells solely facilitate MS absorption in the small intestine. PMID:23922388

Reineke, Joshua J; Cho, Daniel Y; Dingle, Yu-Ting; Morello, A Peter; Jacob, Jules; Thanos, Christopher G; Mathiowitz, Edith

2013-08-06

196

Unique insights into the intestinal absorption, transit, and subsequent biodistribution of polymer-derived microspheres.  

UK PubMed Central (United Kingdom)

Polymeric microspheres (MSs) have received attention for their potential to improve the delivery of drugs with poor oral bioavailability. Although MSs can be absorbed into the absorptive epithelium of the small intestine, little is known about the physiologic mechanisms that are responsible for their cellular trafficking. In these experiments, nonbiodegradable polystyrene MSs (diameter range: 500 nm to 5 µm) were delivered locally to the jejunum or ileum or by oral administration to young male rats. Following administration, MSs were taken up rapidly (?5 min) by the small intestine and were detected by transmission electron microscopy and confocal laser scanning microscopy. Gel permeation chromatography confirmed that polymer was present in all tissue samples, including the brain. These results confirm that MSs (diameter range: 500 nm to 5 µm) were absorbed by the small intestine and distributed throughout the rat. After delivering MSs to the jejunum or ileum, high concentrations of polystyrene were detected in the liver, kidneys, and lungs. The pharmacologic inhibitors chlorpromazine, phorbol 12-myristate 13-acetate, and cytochalasin D caused a reduction in the total number of MSs absorbed in the jejunum and ileum, demonstrating that nonphagocytic processes (including endocytosis) direct the uptake of MSs in the small intestine. These results challenge the convention that phagocytic cells such as the microfold cells solely facilitate MS absorption in the small intestine.

Reineke JJ; Cho DY; Dingle YT; Morello AP 3rd; Jacob J; Thanos CG; Mathiowitz E

2013-08-01

197

Beneficial effect of recombinant human growth hormone on the intestinal mucosa barrier of septic rats  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The objective of the present study was to investigate the effects of recombinant human growth hormone (rhGH) on the intestinal mucosa barrier of septic rats and explore its possible mechanism. Female Sprague-Dawley rats were randomized into three groups: control, Escherichia coli-induced sepsis (S) and treatment (T) groups. Groups S and T were subdivided into subgroups 1d and 3d, respectively. Expression of liver insulin-like growth factor-1 (IGF-1) mRNA, Bcl-2 and Bax pr (more) otein levels and the intestinal Bax/Bcl-2 ratio, and plasma GH and IGF-1 levels were determined. Histological examination of the intestine was performed and bacterial translocation was determined. rhGH significantly attenuated intestinal mucosal injuries and bacterial translocation in septic rats, markedly decreased Bax protein levels, inhibited the decrease of Bcl-2 protein expression and maintained the Bax/Bcl-2 ratio in the intestine. rhGH given after sepsis significantly improved levels of plasma GH (T1d: 1.28 ± 0.24; T3d: 2.14 ± 0.48 µg/L vs S1d: 0.74 ± 0.12; S3d: 0.60 ± 0.18 µg/L; P

Yi, C.; Cao, Y.; Wang, S.R.; Xu, Y.Z.; Huang, H.; Cui, Y.X.; Huang, Y.

2007-01-01

198

Comparative quantification of human intestinal bacteria based on cPCR and LDR/LCR  

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Full Text Available AIM: To establish a multiple detection method based on comparative polymerase chain reaction (cPCR) and ligase detection reaction (LDR)/ligase chain reaction (LCR) to quantify the intestinal bacterial components. METHODS: Comparative quantification of 16S rDNAs from different intestinal bacterial components was used to quantify multiple intestinal bacteria. The 16S rDNAs of different bacteria were amplified simultaneously by cPCR. The LDR/LCR was examined to actualize the genotyping and quantification. Two beneficial (Bifidobacterium, Lactobacillus) and three conditionally pathogenic bacteria (Enterococcus, Enterobacterium and Eubacterium) were used in this detection. With cloned standard bacterial 16S rDNAs, standard curves were prepared to validate the quantitative relations between the ratio of original concentrations of two templates and the ratio of the fluorescence signals of their final ligation products. The internal controls were added to monitor the whole detection flow. The quantity ratio between two bacteria was tested. RESULTS: cPCR and LDR revealed obvious linear correlations with standard DNAs, but cPCR and LCR did not. In the sample test, the distributions of the quantity ratio between each two bacterial species were obtained. There were significant differences among these distributions in the total samples. But these distributions of quantity ratio of each two bacteria remained stable among groups divided by age or sex. CONCLUSION: The detection method in this study can be used to conduct multiple intestinal bacteria genotyping and quantification, and to monitor the human intestinal health status as well.

Zhou-Rui Tang; Kai Li; Yu-Xun Zhou; Zhen-Xian Xiao; Jun-Hua Xiao; Rui Huang; Guo-Hao Gu

2012-01-01

199

Cytokine response of human mononuclear cells induced by intestinal Clostridium species.  

UK PubMed Central (United Kingdom)

Altered composition of intestinal microbiota has been associated with various immunological disorders such as inflammatory bowel disease. Although Clostridium species are major inhabitants of the intestinal tract, their interaction with the host immunological system is yet poorly characterized. In this study, cytokine responses of human monocytic cell line THP-1 and peripheral blood mononuclear cells (PBMC) to six type strains representing common intestinal clostridial species were determined. The strains induced diverse cytokine responses in both THP-1 cells and PBMC. Clostridium perfringens was the most potent inducer of both tumour necrosis factor alpha (TNF-alpha) and interleukin-10 (IL-10), as compared to Clostridium histolyticum, Clostridium clostridioforme, Clostridium leptum, Clostridium sporosphaeroides and Blautia coccoides. Interleukin-8 (IL-8) production in PBMC was most efficiently stimulated by C. sporosphaeroides. The same PBMC preparations that responded strongly to Escherichia coli lipopolysaccharide (LPS) also responded strongly to bacterial stimulation. This indicates that the level of responsiveness is an individual feature of mononuclear cell preparations, and that the overall cytokine response is composed by a combination of host factors and microbial structures affecting them. This work supports the idea that the composition of the intestinal clostridial population influences immune responses and is likely to play an important role in intestinal homeostasis.

Tuovinen E; Keto J; Nikkilä J; Mättö J; Lähteenmäki K

2013-02-01

200

Frog intestinal sac as an in vitro method for the assessment of intestinal permeability in humans: Application to carrier transported drugs.  

Science.gov (United States)

The aim of this study was to investigate the presence of pharmaceutically relevant drug transporters in frog intestine which has been proposed as model for intestinal permeability screening assays of passively absorbed drugs in humans [Trapani, G., Franco, M., Trapani, A., Lopedota, A., Latrofa, A., Gallucci, E., Micelli, S., Liso, G., 2004. Frog intestinal sac: a new in vitro method for the assessment of intestinal permeability. J. Pharm. Sci. 93, 2909-2919]. The expression of transporters in frog intestine was supported by the following observations: (i) the involvement of purine nucleobase transport system was deduced by inhibition of acyclovir transport in the presence of adenine; (ii) baclofen or l-dopa transport was inhibited by the digitalis steroid ouabain and it may be related to the Na(+) electrochemical potential difference, presumably involving amino acid transporters; (iii) the presence of proton-dependent peptide transporters was argued evaluating the effect of the pH change (from pH 5.9 to pH 7.4) on the transport of glutathione; (iv) the possible expression in the frog intestine of an efflux system distinct from P-glycoprotein (Pgp) in the benzylpenicillin transport was deduced using a glucose enriched frog Ringer with or without the known Pgp inhibitor verapamil; (v) the contribution of Pgp-mediated efflux system in determining the frog intestinal absorption of drugs was supported by the specific inhibition of cimetidine or nadolol transport in the presence of verapamil. These results indicate that pharmaceutically relevant drug transporters should be also expressed in frog intestine. In this work, an attempt was also made to compare the measured P(app) values in the frog intestinal model for the aforementioned series of actively/effluxed transported drugs in humans to the corresponding literature values for the fraction absorbed. The P(app) values used in these comparisons were obtained at high concentrations of drugs at which probably saturation of the carrier occurs. Interestingly, it was found that drugs that are completely absorbed had P(app) values >3 x 10(-6)cm/s, while drugs absorbed <90% had P(app) values lower than 1 x 10(-6)cm/s. In these cases, indeed, a borderline region characterized by the apparent permeability coefficient P(app) value between 1 x 10(-6) and 3 x 10(-6)cm/s should be considered for which the prediction of the absorbed fraction after oral administration in humans become more uncertain by the frog intestinal sac system. PMID:18055143

Franco, Massimo; Lopedota, Angela; Trapani, Adriana; Cutrignelli, Annalisa; Meleleo, Daniela; Micelli, Silvia; Trapani, Giuseppe

2007-12-11

 
 
 
 
201

Diversity of Halophilic Archaea in Fermented Foods and Human Intestines and Their Application.  

UK PubMed Central (United Kingdom)

Archaea are prokaryotic organisms distict from bacteria in the structural and molecular biological sense, and these microorganisms are known to mostly thrive at extreme environments. In particular, most studies on halophilic archaea have been focused on environmental and ecological researches. However, new species of halophilic archaea are being isolated and identified from high salt-fermented foods consumed by human, and it has been found that various types of halophilic archaea exist in food products by culture-independent molecular biological methods. In addition, even if the numbers are not quite high, DNAs of various halophilic archaea are being detected in human intestines and much interest is given to their possible roles. This review aims to summarize the types and characteristics of halophilic archaea reported to be present in foods and human intestines and also discuss their application as well.

Lee HS

2013-09-01

202

The effect of probiotic bacteria on the adhesion of pathogens to human intestinal mucus.  

UK PubMed Central (United Kingdom)

Human intestinal glycoproteins extracted from faeces were used as a model for intestinal mucus to investigate adhesion of pathogenic Escherichia coli and Salmonella strains, and the effect of probiotics on this adhesion. S-fimbriated E. coli expressed relatively high adhesion in the mucus model, but the other tested pathogens adhered less effectively. Probiotic strains Lactobacillus GG and L. rhamnosus LC-705 as well as a L. rhamnosus isolated from human faeces were able to slightly reduce S-fimbria-mediated adhesion. Adhesion of S. typhimurium was significantly inhibited by probiotic L. johnsonii LJ1 and L. casei Shirota. Lactobacillus GG and L. rhamnosus (human isolate) increased the adhesion of S. typhimurium suggesting that the pathogen interacts with the probiotic.

Tuomola EM; Ouwehand AC; Salminen SJ

1999-11-01

203

Monitoring and survival of Lactobacillus gasseri SBT2055 in the human intestinal tract.  

Science.gov (United States)

The monitoring and survival of Lactobacillus gasseri SBT2055 in the human intestinal tract was investigated with seven healthy subjects having a low number of fecal lactobacilli. An increase of fecal lactobacilli (10(3.2-5.2) CFU/g feces) was recognized after ingestion of yogurt with SBT2055 by the subjects. A high positive rate of L. gasseri in fecal lactobacilli detected from the subjects (over 70% at 2nd weeks of feeding) was also observed during the ingestion period using the species-specific PCR system. These findings indicate that the SBT2055 strain in yogurt survived in the human intestinal tract and was recovered from human feces. PMID:17116981

Takahashi, Hidetoshi; Fujita, Takashi; Suzuki, Yutaka; Benno, Yoshimi

2006-01-01

204

A wireless capsule robot with spiral legs for human intestine.  

UK PubMed Central (United Kingdom)

BACKGROUND: As an attractive alternative to traditional diagnostic techniques, wireless capsule endoscopy (WCE) can be considered a disruptive technology. METHODS: This paper presents a wirelessly powered micro-robot based on the Archimedes spiral with high integration of an active locomotion module. RESULTS: A WCE prototype was fabricated and tested. Including the video camera and end cap, the outer dimensions of the capsule were diameter (?) 16 mm, length 45 mm. Experiments demonstrated that the anchoring force can overcome 2.6 N wrap force on each leg. The anchoring force was improved to 1.486 with textured legs. A series of ex vivo experiments evaluated capsule performance and ability to traverse the intestine at an average speed of 2.3 cm/min. The wireless power transmission utilized a cylinder ferrite-core in the receiving coil-set, which significantly improved the coupling efficiency (to 12%) in the direction close (and parallel) to the transmitting coil. CONCLUSIONS: Although improvements of the wireless power transmission should target increased stability, this WCE device is both safe and practical for endoscopy. Copyright © 2013 John Wiley & Sons, Ltd.

Chen W; Yan G; Wang Z; Jiang P; Liu H

2013-07-01

205

Comparison of selective M3 and nonselective muscarinic receptor antagonists on gastrointestinal transit and bowel habits in humans.  

UK PubMed Central (United Kingdom)

Although in vitro studies show that muscarinic M(3) receptors primarily mediate the effects of acetylcholine on gastrointestinal contractility, the muscarinic receptor subtypes regulating gastrointestinal motor activity and transit in humans in vivo are unclear. We hypothesized that muscarinic M(3)-specific but not nonspecific receptor antagonists would delay gastrointestinal and colonic transit in humans. In this parallel-group study, gastric emptying, small intestinal transit, and colonic transit were assessed by scintigraphy on days 4-6 in 72 healthy subjects (49 women) who received placebo (n = 16), the M(3) antagonist darifenacin ER [7.5 mg (n = 20) or 15 mg daily (n = 17)], or the nonspecific antagonist tolterodine [4 mg daily (n = 19)] for 6 days. Bowel habits were recorded by daily diaries. Both doses of darifenacin substantially delayed [P < 0.01 vs. placebo (for both doses), P < 0.01 vs. tolterodine (for 15 mg)] small intestinal transit, i.e., colonic filling at 6 h (placebo [59.6 +/- 6.4%, mean +/- SE], 7.5 mg ER [34.4 +/- 6.1%], 15 mg ER [20.4 +/- 6.3%)]. Darifenacin (15 mg) also delayed (P < 0.01 vs. placebo and tolterodine) half-time for ascending colonic emptying [placebo (12.0 +/- 1.5 h), 7.5 mg (18.6 +/- 1.9 h), 15 mg (22.9 +/- 2.6 h)] and colonic transit (geometric center) at 24 [placebo (2.8 +/- 0.2), 7.5 mg (2.4 +/- 0.2), 15 mg (1.9 +/- 0.2)] but not 48 h. Darifenacin did not affect gastric emptying and tolterodine did not affect bowel habits or gastrointestinal transit. With muscarinic antagonists used at clinically approved doses, these findings demonstrate that muscarinic M(3) receptors regulate small intestinal and colonic transit in humans; colonic effects are more pronounced in the right than left colon. At doses that affect small and large intestinal transit, M(3) antagonists do not affect gastric emptying in humans. The efficacy of darifenacin in diarrhea-predominant irritable bowel syndrome should be evaluated.

Bharucha AE; Ravi K; Zinsmeister AR

2010-07-01

206

Heterogeneity of HLA-DR-positive histiocytes in human intestinal lamina propria: a combined histochemical and immunohistological analysis.  

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HLA-DR-positive histiocytes in the lamina propria of the human intestine have been characterised using combined histochemical and immunohistological techniques. In the small intestine, 80-90% of the HLA-DR+ histiocytes had irregular surfaces with stellate processes, and exhibited strong membrane ade...

Selby, WS; Poulter, LW; Hobbs, S; Jewell, DP; Janossy, G

207

Expression and significance of C-fos and proliferating cell nuclear antigen in the small intestinal tissue of human fetus  

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Full Text Available Objective To explore the expression rule of proliferating cell nuclear antigen(PCNA),C-fos proteins and apoptosis genes in the small intestinal tissue of human fetus.Methods At the second-to fourth-month of gestation,the expressions of cell proliferation and apoptosis were observed in 16 specimens of human fetal small intestinal tissue by using the immunohistochemical methods and terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling(TUNEL).Results At the second to fourth month of gestation,all the PCNA and C-fos proteins were positively expressed in the small intestinal tissues and cells of human fetus.With the increase in gestational period,the positive cell number and average intensity(AI) of PCNA protein increased gradually(P < 0.01).The positive cell number of C-fos protein increased first,and then decreased,while the AI of C-fos protein stably increased in the small intestinal tissues and cells of human fetus(P < 0.01).At the second to fourth month of gestation,TUNEL positive cells were seen to distribute in each layer of the small intestinal tissues of human fetus.With the increase of age,all the positive cell number and AI of TUNEL positive cells showed a tendency of decrease following increase in the small intestine of human fetus(P < 0.01).Conclusions PCNA,C-fos and apoptosis gene participate in adjusting the growth and development of the cells and tissues in the small intestine of human fetus.In the third month of gestation,especially,proliferation and apoptosis are significantly increased in the small intestinal tissue of human fetus,which may be the key period of intestinal tissue development.

Xue-hong LIU; Yong ZHANG

2011-01-01

208

Similarity of hydrolyzing activity of human and rat small intestinal disaccharidases  

Directory of Open Access Journals (Sweden)

Full Text Available Tsuneyuki Oku¹, Kenichi Tanabe¹, Shigeharu Ogawa², Naoki Sadamori¹, Sadako Nakamura¹¹Graduate School of Human Health Science, University of Nagasaki, Siebold, Nagayo, Japan; ²Juzenkai Hospital, Kagomachi, Nagasaki, JapanBackground: The purpose of this study was to clarify whether it is possible to extrapolate results from studies of the hydrolyzing activity of disaccharidases from rats to humans.Materials and methods: We measured disaccharidase activity in humans and rats using identical preparation and assay methods, and investigated the similarity in hydrolyzing activity. Small intestinal samples without malignancy were donated by five patients who had undergone bladder tumor surgery, and homogenates were prepared to measure disaccharidase activity. Adult rat homogenates were prepared using small intestine.Results: Maltase activity was the highest among the five disaccharidases, followed by sucrase and then palatinase in humans and rats. Trehalase activity was slightly lower than that of palatinase in humans and was similar to that of sucrase in rats. Lactase activity was the lowest in humans, but was similar to that of palatinase in rats. Thus, the hydrolyzing activity of five disaccharidases was generally similar in humans and rats. The relative activity of sucrose and palatinase versus maltase was generally similar between humans and rats. The ratio of rat to human hydrolyzing activity of maltase, sucrase, and palatinase was 1.9–3.1, but this was not a significant difference. Leaf extract from Morus alba strongly inhibited the activity of maltase, sucrase, and palatinase, but not trehalase and lactase, and the degree of inhibition was similar in humans and rats. L-arabinose mildly inhibited sucrase activity, but hardly inhibited the activity of maltase, palatinase, trehalase and lactase in humans and rats. The digestibility of 1-kestose, galactosylsucrose, and panose by small intestinal enzymes was very similar between humans and rats.Conclusion: These results demonstrate that the digestibility of newly developed saccharide materials evaluated by rat small intestinal enzymes can substitute for evaluation using human enzymes.Keywords: disaccharidase, maltase, sucrase, trehalase, palatinase, digestibility

Oku T; Tanabe K; Ogawa S; Sadamori N; Nakamura S

2011-01-01

209

Purification and fermentation in vitro of sesaminol triglucoside from sesame cake by human intestinal microbiota.  

Science.gov (United States)

Sesaminol triglucoside (STG), the most abundant lignan glycoside existing in sesame cake/meal, has exhibited various biological activities. However, little information about its in vitro fermentation with intestinal microbiota is available. Therefore, the effect of STG from sesame cake on the fermentation of human fecal microbiota was evaluated. First, high-purity STG was successfully prepared from defatted sesame cake by extraction with 80% ethanol and simple purification procedures of polyamide column chromatography and Toyopearl HW-40S column chromatography. Then the influence of STG on intestinal microbiota was conducted by monitoring bacterial populations and analyzing the concentrations of short-chain fatty acids (SCFA). We found that STG could significantly induce an increase in numbers of Lactobacillus - Enterococcus group and Bifidobacterium in fermentation in vitro with human fecal microbiota, while it did not stimulate the bacterial growth of Eubacterium rectale - Clostridium coccoides group, Clostridium histolyticum group, and Bacteroides - Prevotella group. Furthermore, it was found that concentrations of formic, acetic, propionic, and butyric acids in STG culture increased significantly during the fermentation, and its total SCFA concentration was relatively higher than those of the control and glucose cultures at 6 and 12 h fermentation. Our findings provided further evidence for the importance of human intestinal bacteria in the bioactivity of STG and its metabolites in the maintenance of human health. PMID:23387872

Zhu, Xiuling; Zhang, Xin; Sun, Yongkang; Su, Di; Sun, Yi; Hu, Bing; Zeng, Xiaoxiong

2013-02-18

210

Purification and fermentation in vitro of sesaminol triglucoside from sesame cake by human intestinal microbiota.  

UK PubMed Central (United Kingdom)

Sesaminol triglucoside (STG), the most abundant lignan glycoside existing in sesame cake/meal, has exhibited various biological activities. However, little information about its in vitro fermentation with intestinal microbiota is available. Therefore, the effect of STG from sesame cake on the fermentation of human fecal microbiota was evaluated. First, high-purity STG was successfully prepared from defatted sesame cake by extraction with 80% ethanol and simple purification procedures of polyamide column chromatography and Toyopearl HW-40S column chromatography. Then the influence of STG on intestinal microbiota was conducted by monitoring bacterial populations and analyzing the concentrations of short-chain fatty acids (SCFA). We found that STG could significantly induce an increase in numbers of Lactobacillus - Enterococcus group and Bifidobacterium in fermentation in vitro with human fecal microbiota, while it did not stimulate the bacterial growth of Eubacterium rectale - Clostridium coccoides group, Clostridium histolyticum group, and Bacteroides - Prevotella group. Furthermore, it was found that concentrations of formic, acetic, propionic, and butyric acids in STG culture increased significantly during the fermentation, and its total SCFA concentration was relatively higher than those of the control and glucose cultures at 6 and 12 h fermentation. Our findings provided further evidence for the importance of human intestinal bacteria in the bioactivity of STG and its metabolites in the maintenance of human health.

Zhu X; Zhang X; Sun Y; Su D; Sun Y; Hu B; Zeng X

2013-02-01

211

The roles of dopamine receptor and adrenoreceptor on the inhibition of gastric emptying and intestinal transit by amphetamine in male rats.  

UK PubMed Central (United Kingdom)

Amphetamine, a central nervous stimulant, acts on the central nervous system (CNS) by increasing levels of norepinephrine, serotonin and dopamine (DA) in the brain. It stimulates the colonic motility and gastrointestinal (GI) function via the brain-gut connections as well as diminishes appetite to control bodyweight, but the mechanism between amphetamine and GI motility was unclear. We investigated the role of DA receptor and adrenoreceptor in the inhibitory effects of amphetamine on GI motility in male rats. After fasting overnight, the male rats received an intraperitoneal (i.p.) injection of amphetamine (3 mg/ml/kg) 15 min after i.p. injection of different antagonists for dopamine receptors and adrenoreceptors. Gastric emptying and intestinal transit were assessed 15 min after intragastric instillation of a test meal containing radioactive Na??¹CrO? and 10% charcoal. Haloperidol, a DA receptor antagonist, acting exactly as the selective D? receptor antagonist, eticlopride, completely prevented amphetamineinduced inhibition of gastric emptying and intestinal transit in male rats. The selective D? receptor antagonist, SCH 23390, significantly attenuated the amphetamine-induced inhibition of gastric emptying and intestinal transit in male rats. Both selective and nonselective ? adrenoreceptor antagonist, phentolamine, prazosin and yohimbine, did not reverse the inhibitory effects of amphetamine on gastric emptying and intestinal transit. Propanolol, a ? adrenoreceptor antagonist, partially attenuated the amphetamine-induced inhibition of gastric emptying but did not significantly attenuate intestinal transit. These results suggest that amphetamine-induced inhibition of gastric emptying and intestinal transit is mediated by an action on dopaminergic mechanism and adrenoreceptor with little involvement. These findings may clarify the influence of central nervous stimulant on GI tract and may provide the appropriate medication in CNS.

Huang WJ; Chien EJ

2012-08-01

212

C-ring cleavage of flavonoids by human intestinal bacteria.  

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Four hitherto undescribed Clostridium strains capable of cleaving the C ring of quercetin, kaempferol, and naringenin at C-3-C-4 were isolated from the fecal flora of humans. None of the strains cleaved catechin. C-ring fission occurred when the substrate was either in solution or in suspension. Mix...

Winter, J; Moore, L H; Dowell, V R; Bokkenheuser, V D

213

Comparison of rat and human intestinal perfusion models for assessing efficacy of oral rehydration solutions.  

UK PubMed Central (United Kingdom)

The optimal composition for oral rehydration solutions remains controversial. Animal models have been used to assess the efficacy of new formulations but the relevance of these studies to the handling of oral rehydration solutions in human intestine during diarrhoeal disease states remains uncertain. Using steady state perfusion techniques we have compared water and solute transport from a variety of oral rehydration solutions in both the entire rat small intestine and in the human jejunum. Overall the pattern of water, sodium and glucose absorption was similar from the three oral rehydration solutions tested, indicating close parallelism between the two models despite the species and methodological differences. Although the relationship between the findings of these studies to the handling of oral rehydration solution in diarrhoeal disease states remains uncertain, we believe they do support the view that animal models may have a part to play in the preliminary screening of oral rehydration solutions before clinical trial.

Hunt JB; Elliott EJ; Farthing MJ

1991-02-01

214

Induction of human defensins by intestinal Caco-2 cells after interactions with opportunistic Candida species.  

UK PubMed Central (United Kingdom)

In this study we investigated the effects of Candida albicans, C. krusei, C. tropicalis and C. parapsilosis on human beta-defensin 2 (HBD-2) production in Caco-2 intestinal cell line, and the production of alpha-defensins (human neutrophil peptides, HNP1-3) in peripheral blood. Opportunistic pathogen yeasts can modulate the host immune function by inducing defensins, the natural antimicrobial peptides. Here we show that Candida spp. stimulated HBD-2 expression in and release from Caco-2 cells, with C. albicans inducing the highest levels of HBD-2. Similarly, HNP1-3 secretion was significantly increased in whole blood after exposure to Candida yeast cells, with C. albicans producing the greatest effect. Our investigations underscore the important role of beta and alpha defensins produced by intestinal epithelial cells locally and neutrophils systemically in the antifungal defense against Candida.

Gácser A; Tiszlavicz Z; Németh T; Seprényi G; Mándi Y

2013-10-01

215

Response of human intestinal lamina propria T lymphocytes tointerleukin 12: additive effects of interleukin 15 and 7  

Digital Repository Infrastructure Vision for European Research (DRIVER)

the mucosal response during intestinal inflammation but its role is not fully understood. The response of human lamina propria T lymphocytes (T-LPL) to IL-12 in terms of interferon ? (IFN-?) release and proliferation was investigated, exploring wheth...

Monteleone, G; Parrello, T; Luzza, F; Pallone, F

216

Autoradiographic quantification of vasoactive intestinal peptide binding sites in sections from human blood mononuclear cell pellets  

Energy Technology Data Exchange (ETDEWEB)

Quantitative autoradiographic methods were utilized to characterize specific, high-affinity vasoactive intestinal peptide binding sites (Kd = 310 +/- 60 pmol/L; Bmax = 93 +/- 11 fmol/mg protein) in frozen sections obtained from a mononuclear cell pellet derived from 20 ml of human blood. The method is at least one order of magnitude more sensitive than conventional membrane binding techniques, and it has the potential for wide applications in studies of neuropeptide, biogenic amine, and drug binding in clinical samples.

Gutkind, J.S.; Kurihara, M.; Castren, E.; Saavedra, J.M.

1988-09-01

217

Rapid and accurate diagnosis of human intestinal spirochetosis by fluorescence in situ hybridization.  

UK PubMed Central (United Kingdom)

Human intestinal spirochetosis (HIS) is associated with overgrowth of the large intestine by spirochetes of the genus Brachyspira. The microbiological diagnosis of HIS is hampered by the fastidious nature and slow growth of Brachyspira spp. In clinical practice, HIS is diagnosed histopathologically, and a significant portion of cases may be missed. Fluorescence in situ hybridization (FISH) is a molecular method that allows the visualization and identification of single bacteria within tissue sections. In this study, we analyzed intestinal biopsy samples from five patients with possible HIS. All specimens yielded positive results by histopathological techniques. PCR amplification and sequencing of the 16S rRNA gene were performed. Sequences of two isolates clustered in the group of Brachyspira aalborgi, whereas in three cases, the sequences were highly similar to that of Brachyspira pilosicoli. Three phylotypes showed mismatches at distinct nucleotide positions with Brachyspira sp. sequences published previously. In addition, culture for Brachyspira was successful in three cases. On the basis of these data, we designed and evaluated a Brachyspira genus-specific 16S rRNA-directed FISH probe that detects all of the Brachyspira spp. published to date. FISH of biopsy samples resulted in strong, unequivocal signals of brush-like formations at the crypt surfaces. This technique allowed simultaneous visualization of single spirochetes and their identification as Brachyspira spp. In conclusion, FISH provides a fast and accurate technique for the visualization and identification of intestinal spirochetes in tissue sections. It therefore represents a valuable tool for routine diagnosis of HIS.

Schmiedel D; Epple HJ; Loddenkemper C; Ignatius R; Wagner J; Hammer B; Petrich A; Stein H; Göbel UB; Schneider T; Moter A

2009-05-01

218

Anaerobic metabolism of 1-amino-2-naphthol-based azo dyes (Sudan dyes) by human intestinal microflora.  

UK PubMed Central (United Kingdom)

The rates of metabolism of Sudan I and II and Para Red by human intestinal microflora were high compared to those of Sudan III and IV under anaerobic conditions. Metabolites of the dyes were identified as aniline, 2,4-dimethylaniline, o-toluidine, and 4-nitroaniline through high-performance liquid chromatography and liquid chromatography electrospray ionization tandem mass spectrometry analyses. These data indicate that human intestinal bacteria are able to reduce Sudan dyes to form potentially carcinogenic aromatic amines.

Xu H; Heinze TM; Chen S; Cerniglia CE; Chen H

2007-12-01

219

Species differences in hepatic and intestinal metabolic activities for 43 human cytochrome P450 substrates between humans and rats or dogs.  

UK PubMed Central (United Kingdom)

Abstract 1. ??Prediction of human pharmacokinetics might be made more precise by using species with similar metabolic activities to humans. We had previously reported the species differences in intestinal and hepatic metabolic activities of 43 cytochrome P450 (CYP) substrates between cynomolgus monkeys and humans. However, the species differences between humans and rats or dogs had not yet been determined using comparable data sets with sufficient number of compounds. 2. ??Here, we investigated metabolic stabilities in intestinal and liver microsomes obtained from rats, dogs and humans using 43 substrates of human CYP1A2, CYP2J2, CYP2C, CYP2D6 and CYP3A. 3. ??Hepatic intrinsic clearance (CLint) values for most compounds in dogs were comparable to those in humans (within 10-fold), whereas in rats, those for the human CYP2D6 substrates were much higher and showed low correlation with humans. In dog intestine, as with human intestine, CLint values for almost all human CYP1A2, CYP2C, CYP2D6 substrates were not determined because they were very low. Intestinal CLint values for human CYP3A substrates in rats and dogs appeared to be lower for most of the compounds and showed moderate correlation with those in humans. 4. ??In conclusion, dogs showed the most similar metabolic activity to humans.

Nishimuta H; Nakagawa T; Nomura N; Yabuki M

2013-04-01

220

Species differences in hepatic and intestinal metabolic activities for 43 human cytochrome P450 substrates between humans and rats or dogs.  

Science.gov (United States)

Abstract 1. ??Prediction of human pharmacokinetics might be made more precise by using species with similar metabolic activities to humans. We had previously reported the species differences in intestinal and hepatic metabolic activities of 43 cytochrome P450 (CYP) substrates between cynomolgus monkeys and humans. However, the species differences between humans and rats or dogs had not yet been determined using comparable data sets with sufficient number of compounds. 2. ??Here, we investigated metabolic stabilities in intestinal and liver microsomes obtained from rats, dogs and humans using 43 substrates of human CYP1A2, CYP2J2, CYP2C, CYP2D6 and CYP3A. 3. ??Hepatic intrinsic clearance (CLint) values for most compounds in dogs were comparable to those in humans (within 10-fold), whereas in rats, those for the human CYP2D6 substrates were much higher and showed low correlation with humans. In dog intestine, as with human intestine, CLint values for almost all human CYP1A2, CYP2C, CYP2D6 substrates were not determined because they were very low. Intestinal CLint values for human CYP3A substrates in rats and dogs appeared to be lower for most of the compounds and showed moderate correlation with those in humans. 4. ??In conclusion, dogs showed the most similar metabolic activity to humans. PMID:23593983

Nishimuta, Haruka; Nakagawa, Tetsuya; Nomura, Naruaki; Yabuki, Masashi

2013-04-17

 
 
 
 
221

Activation of the Epithelial-to-Mesenchymal Transition Factor Snail Mediates Acetaldehyde-Induced Intestinal Epithelial Barrier Disruption.  

UK PubMed Central (United Kingdom)

BACKGROUND: Acetaldehyde (AcH) is mutagenic and can reach high concentrations in colonic lumen after ethanol consumption and is associated with intestinal barrier dysfunction and an increased risk of progressive cancers, including colorectal carcinoma. Snail, the transcription factor of epithelial-mesenchymal transition, is known to down-regulate expression of tight junction (TJ) and adherens junction (AJ) proteins, resulting in loss of epithelial integrity, cancer progression, and metastases. As AcH is mutagenic, the role of Snail in the AcH-induced disruption of intestinal epithelial TJs deserves further investigation. Our aim was to investigate the role of oxidative stress and Snail activation in AcH-induced barrier disruption in Caco-2 monolayers. METHODS: The monolayers were exposed from the apical side to AcH ± L-cysteine. Reactive oxygen species (ROS) generation and Snail activation were assessed by ELISA and immunofluorescence. Paracellular permeability, localization, and expression of ZO-1, occludin, E-cadherin, and ?-catenin were examined using transepithelial electrical resistance (TEER), fluorescein isothiocyanate-labeled dextran 4 kDa (FITC-D4), immunofluorescence, and ELISA, respectively. Involvement of Snail was further addressed by inhibiting Snail using small interfering RNA (siRNA). RESULTS: Exposure to 25 ?M AcH increased ROS generation and ROS-dependently induced Snail phosphorylation. In addition, AcH increased paracellular permeability (decrease in TEER and increase in FITC-D4 permeation) in association with redistribution and decrease of TJ and AJ protein levels, which could be attenuated by L-cysteine. Knockdown of Snail by siRNA attenuated the AcH-induced redistribution and decrease in the TJ and AJ proteins, in association with improvement of the barrier function. CONCLUSIONS: Our data demonstrate that oxidative stress-mediated Snail phosphorylation is likely a novel mechanism contributing to the deleterious effects of AcH on the TJ and AJ, and intestinal barrier function.

Elamin E; Masclee A; Troost F; Dekker J; Jonkers D

2013-08-01

222

Utilização do método videolaparoscopico na reconstituição do trânsito intestinal após a operação de Hartmann The use of videolaparoscopic approach in the intestinal transit restoration after Hartmann's procedure  

Directory of Open Access Journals (Sweden)

Full Text Available O objetivo é apresentar a padronização da técnica operatória e os resultados obtidos com a utilização do acesso videolaparoscópico na reconstituição do trânsito intestinal em pacientes previamente submetidos à operação de Hartmann por causas diversas. Foram analisados prospectivamente 32 pacientes, no período de dezembro de 1991 a junho de 1997, com distribuição semelhante com relação ao sexo e com idade média de 42,4 anos. Todos os pacientes foram submetidos ao mesmo preparo pré-operatório e à mesma técnica cirúrgica. Ocorreram três (9,3%) complicações transoperatórias. Uma (3,1 %) anastomose mecânica incompleta, necessitando de endossutura manual, uma (3,1 %) laceração do reto com o grampeador mecânico e uma (3,1 %) lesão da artéria epigástrica direita. Ocorreram ainda três (9,3%) conversões, sendo uma (3,1 %) devido à laceração do reto com o grampeador mecânico, outra (3.1 %) pela invasão tumoral na pelve e outra (3,1 %) pela presença de excessivas aderências intraperitoneais. O tempo operatório variou de 30 a 240 minutos, na média de 126,2 minutos (2,1 horas). A evolução clínica pós-operatória foi satisfatória. Nove (31,0%) pacientes não referiram dor, enquanto 13 (44,8%) a referiram em pequena intensidade, e apenas sete (24,0%) queixaram-se de dor com maior intensidade. A dieta líquida via oral foi instituída no período médio de 1,6 dias, e a primeira evacuação ocorreu na média de 3,2 dias de pós-operatório. O período médio de hospitalização foi de 4,7 dias. Ocorreram complicações pós-operatórias em oito (27,5%) pacientes. Duas (6,8%) infecções da ferida do estoma, dois pacientes (6,8%) com dor no ombro direito, uma (3,4%) deiscência de anastomose, um (3,4%) caso de peritonite por provável contaminação do material cirúrgico, uma coleção líquida pélvica e uma hérnia incisional. Em conclusão, a reconstituição do trânsito intestinal por videolaparoscopia apresentou-se segura e eficaz, podendo constituir-se no método cirúrgico de escolha, pois foi utilizada com sucesso em 90,6% dos pacientes.We present the operative technique and the results of the laparoscopic approach for Hartmann's colostomy reversal. Thirty two patients were prospectively analysed from december 1991 to june 1997. They presented a similar incidence regarding sex distribution, and a median age of 42.4 years old. Ali patients underwent the same preoperative preparation and operative technique. Three (9.3%) intraoperative complications were observed: an uncompleted anastomosis (3.1%), requiring an endosuture, a rectal perforation by the mechanical stapler and a right epigastric artery lesion. There were convertion to open surgery in three (9.3%) patients: one (3.1%) due to rectal perforation by the mechanical staple1; one (3.1%) for tumoral pelvic invasion and another because of excessive intra-peritoneal adhesions. Operative time varied from 30 to 240 minutes, with a mean time of 126;2 minutes. Nine (31.0%) patients didn't present pain, while 13 (44.8%) referred minimal pain and seven (24.0%) complained severe pain. Oral liquid diet intake occurred within a mean time of 1.6 days and the first evacuation observed after a mean 3.2 postoperative days. Mean hospitalization time was 4.7 days. Postoperative complications occurred in eight (27.5%) patients. Two (6.8%) stoma wound infections, right shoulder pain in two (6.8%) patients, one (3.4%) anastomotic dehiscence, one peritonitis probably due to contaminationfrom surgical instruments, a liquid pelvic coliection and an incisional haernia. 1n conclusion, videolaparoscopic restoration of the intestinal transit demonstrated to be safe and effective. It could be the method of choice because of its success in 90.6 per cent of the patients.

Francisco Sérgio P. Regadas; Sthela M. Murad Regadas; Lusmar Veras Rodrigues

2000-01-01

223

Correlation between oral drug absorption in humans and apparent drug permeability coefficients in human intestinal epithelial (Caco-2) cells  

Energy Technology Data Exchange (ETDEWEB)

Monolayers of a well differentiated human intestinal epithelial cell line, Caco-2, were used as a model to study passive drug absorption across the intestinal epithelium. Absorption rate constants (expressed as apparent permeability coefficients) were determined for 20 drugs and peptides with different structural properties. The permeability coefficients ranged from approximately 5 x 10{sup {minus} 8} to 5 x 10{sup {minus} 5} cm/s. A good correlation was obtained between data on oral absorption in humans and the results in the Caco-2 model. Drugs that are completely absorbed in humans had permeability coefficients greater than 1 x 10{sup {minus} 6} cm/s. Drugs that are absorbed to greater than 1% but less than 100% had permeability coefficients of 0.1-1.0 x 10{sup {minus} 6} cm/s while drugs and peptides that are absorbed to less than 1% had permeability coefficients of less than or equal to 1 x 10{sup {minus} 7} cm/s. The results indicate that Caco-2 monolayers can be used as a model for studies on intestinal drug absorption.

Artursson, P.; Karlsson, J. (Uppsala Univ., (Sweden))

1991-03-29

224

Vasoactive intestinal polypeptide regulates barrier function via mast cells in human intestinal follicle-associated epithelium and during stress in rats.  

UK PubMed Central (United Kingdom)

BACKGROUND: Vasoactive intestinal polypeptide (VIP) has been implicated as a regulator of intestinal barrier function and inflammation. Our aim was to elucidate the role of VIP in follicle-associated epithelium (FAE) and villus epithelium (VE) permeability following stress in rats and on human intestinal barrier function. METHODS: Rats were injected intraperitoneally (i.p.) with VIP receptor-antagonists (anti-VPACs), a mast cell stabilizer, doxantrazole (DOX), or NaCl, and submitted to acute water avoidance stress. Ileal segments were mounted in Ussing chambers to assess (51) chromium-edta ((51) Cr-edta) and Escherichia (E.) coli (strain K-12) permeability. Rat ileal and human ileal and colonic segments were exposed to VIP ± anti-VPACs or DOX. An in vitro co-culture model of human FAE was used to study epithelial-VIP effects. VIP/VPACs distribution was assessed by microscopy. KEY RESULTS: Stress increased (51) Cr-edta and E. coli permeability in VE and FAE. The increases were abolished by i.p. injection of DOX or anti-VPACs. Ileal VIP-exposure ex vivo increased bacterial passage and this was reduced by DOX. In human FAE ex vivo, VIP treatment doubled bacterial uptake, which was normalized by DOX or anti-VPACs. No barrier effects were observed in human colonic tissue. VPACs were found in rat and human ileal follicles, with partial mast cell co-localization. The co-culture model confirmed VIP-mast cell-epithelial interactions in the regulation of barrier function. CONCLUSIONS & INFERENCES: Stress affects the FAE barrier by mechanisms involving VIP and VPACs on mucosal mast cells. We suggest a regulatory role for VIP in the control of ileal permeability that may be relevant to bacterial-epithelial interactions in stress-related intestinal disorders.

Keita AV; Carlsson AH; Cigéhn M; Ericson AC; McKay DM; Söderholm JD

2013-06-01

225

Identification of isoquercitrin metabolites produced by human intestinal bacteria using UPLC-Q-TOF/MS.  

UK PubMed Central (United Kingdom)

In this paper, ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) and the MetaboLynx™ software combined with mass defect filtering were applied to identity the metabolites of isoquercitrin using an intestinal mixture of bacteria and 96 isolated strains from human feces. The human incubated samples collected for 72 h in the anaerobic incubator and extracted with ethyl acetate were analyzed by UPLC-Q-TOF/MS within 10 min. The parent compound and five metabolites were identified by eight isolated strains, including Bacillus sp. 17, Veillonella sp. 23 and 32 and Bacteroides sp. 40, 41, 56, 75 and 88 in vitro. The results indicate that quercetin, acetylated isoquercitrin, dehydroxylated isoquercitrin, hydroxylated quercetin and hydroxymethylated quercetin are the major metabolites of isoquercitrin. Furthermore, a possible metabolic pathway for the biotransformation of isoquercitrin was established in intestinal flora. This study will be helpful for understanding the metabolic route of isoquercitrin and the role of different intestinal bacteria in the metabolism of natural compounds.

Lu L; Qian D; Yang J; Jiang S; Guo J; Shang EX; Duan JA

2013-04-01

226

Intimin-mediated tissue specificity in enteropathogenic Escherichia coli interaction with human intestinal organ cultures.  

Science.gov (United States)

The hallmark of enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) adhesion to cultured human host cells is intimate attachment and the formation of attaching and effacing (A/E) lesions. Recently, EHEC O157:H7 was shown to induce A/E lesions on human intestinal explants. Unlike EPEC, which colonized the small intestine, EHEC adhesion was restricted to follicle-associated epithelium (FAE) of ileal Peyer's patches. This study tested the hypothesis that the bacterial adhesin intimin contributes to tissue specificity. Complementing the eae gene mutation in CVD206 (derived from EPEC strain E2348/69) with EPEC eaealpha (encoding intimin-alpha) restored the ability to colonize small intestinal mucosa like the parent strain. In contrast, complementing with EHEC eaegamma (encoding intimin-gamma) resulted in the strain adhering and inducing A/E lesion on Peyer's patches, similar to EHEC. An intimin-gamma-positive O55:H7 EPEC also targeted FAE. Thus, intimin contributes to the tissue specificity of A/E lesion-forming microbial pathogens. PMID:10762584

Phillips, A D; Frankel, G

2000-04-13

227

Intimin-mediated tissue specificity in enteropathogenic Escherichia coli interaction with human intestinal organ cultures.  

UK PubMed Central (United Kingdom)

The hallmark of enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) adhesion to cultured human host cells is intimate attachment and the formation of attaching and effacing (A/E) lesions. Recently, EHEC O157:H7 was shown to induce A/E lesions on human intestinal explants. Unlike EPEC, which colonized the small intestine, EHEC adhesion was restricted to follicle-associated epithelium (FAE) of ileal Peyer's patches. This study tested the hypothesis that the bacterial adhesin intimin contributes to tissue specificity. Complementing the eae gene mutation in CVD206 (derived from EPEC strain E2348/69) with EPEC eaealpha (encoding intimin-alpha) restored the ability to colonize small intestinal mucosa like the parent strain. In contrast, complementing with EHEC eaegamma (encoding intimin-gamma) resulted in the strain adhering and inducing A/E lesion on Peyer's patches, similar to EHEC. An intimin-gamma-positive O55:H7 EPEC also targeted FAE. Thus, intimin contributes to the tissue specificity of A/E lesion-forming microbial pathogens.

Phillips AD; Frankel G

2000-04-01

228

Otilonium bromide inhibits calcium entry through L-type calcium channels in human intestinal smooth muscle.  

Science.gov (United States)

Otilonium bromide (OB) is used as an intestinal antispasmodic. The mechanism of action of OB is not completely understood. As Ca(2+) entry into intestinal smooth muscle is required to trigger contractile activity, our hypothesis was that OB blocked Ca(2+) entry through L-type Ca(2+) channels. Our aim was to determine the effects of OB on Ca(2+), Na(+) and K(+) ion channels in human jejunal circular smooth muscle cells and on L-type Ca(2+) channels expressed heterologously in HEK293 cells. Whole cell currents were recorded using standard patch clamp techniques. Otilonium bromide (0.09-9 micromol L(-1)) was used as this reproduced clinical intracellular concentrations. In human circular smooth muscle cells, OB inhibited L-type Ca(2+) current by 25% at 0.9 micromol L(-1) and 90% at 9 micromol L(-1). Otilonium bromide had no effect on Na(+) or K(+) currents. In HEK293 cells, 1 micromol L(-1) OB significantly inhibited the expressed L-type Ca(2+) channels. Truncation of the alpha(1C) subunit C and N termini did not block the inhibitory effects of OB. Otilonium bromide inhibited Ca(2+) entry through L-type Ca(2+) at concentrations similar to intestinal tissue levels. This effect may underlie the observed muscle relaxant effects of the drug. PMID:15086870

Strege, P R; Evangelista, S; Lyford, G L; Sarr, M G; Farrugia, G

2004-04-01

229

Otilonium bromide inhibits calcium entry through L-type calcium channels in human intestinal smooth muscle.  

UK PubMed Central (United Kingdom)

Otilonium bromide (OB) is used as an intestinal antispasmodic. The mechanism of action of OB is not completely understood. As Ca(2+) entry into intestinal smooth muscle is required to trigger contractile activity, our hypothesis was that OB blocked Ca(2+) entry through L-type Ca(2+) channels. Our aim was to determine the effects of OB on Ca(2+), Na(+) and K(+) ion channels in human jejunal circular smooth muscle cells and on L-type Ca(2+) channels expressed heterologously in HEK293 cells. Whole cell currents were recorded using standard patch clamp techniques. Otilonium bromide (0.09-9 micromol L(-1)) was used as this reproduced clinical intracellular concentrations. In human circular smooth muscle cells, OB inhibited L-type Ca(2+) current by 25% at 0.9 micromol L(-1) and 90% at 9 micromol L(-1). Otilonium bromide had no effect on Na(+) or K(+) currents. In HEK293 cells, 1 micromol L(-1) OB significantly inhibited the expressed L-type Ca(2+) channels. Truncation of the alpha(1C) subunit C and N termini did not block the inhibitory effects of OB. Otilonium bromide inhibited Ca(2+) entry through L-type Ca(2+) at concentrations similar to intestinal tissue levels. This effect may underlie the observed muscle relaxant effects of the drug.

Strege PR; Evangelista S; Lyford GL; Sarr MG; Farrugia G

2004-04-01

230

Interaction of macrolide antibiotics with intestinally expressed human and rat organic anion-transporting polypeptides.  

UK PubMed Central (United Kingdom)

The macrolide antibiotics azithromycin and clarithromycin are large molecular weight compounds that exhibit moderate to excellent oral bioavailability in preclinical species and humans. Previous concomitant dosing studies in rats using rifamycin SV, a general organic anion-transporting polypeptide (OATP) inhibitor, suggested that the high oral absorption of azithromycin and clarithromycin may be caused by facilitative uptake by intestinal Oatps. In this study, we used OATP/Oatp-expressing cells to investigate the interaction of macrolides with rat Oatp1a5, human OATP1A2, and human/rat OATP2B1/Oatp2b1. These experiments showed that azithromycin and clarithromycin were potent inhibitors of rat Oatp1a5-mediated taurocholate uptake with apparent inhibitor constant (K(i)) values of 3.3 and 2.4 microM, respectively. The macrolides functioned as noncompetitive inhibitors but were not transport substrates for rat Oatp1a5, as assessed by direct uptake measurements of radiolabeled azithromycin and clarithromycin. cis-Inhibition and direct uptake studies further showed that azithromycin and clarithromycin were only very weak inhibitors and not substrates for human OATP1A2 and human/rat OATP2B1/Oatp2b1. In summary, these results indicate that the macrolides azithromycin and clarithromycin potently inhibit rat Oatp1a5 but do not significantly interact with OATP1A2 and OATP2B1/Oatp2b1. These intestinally expressed OATP/Oatp(s) are not responsible for the postulated facilitative uptake of azithromycin and clarithromycin, and alternative facilitative pathways must exist for their intestinal absorption.

Lan T; Rao A; Haywood J; Davis CB; Han C; Garver E; Dawson PA

2009-12-01

231

Studies on the determination of extracellular galactosyltransferase in human intestinal tissue  

International Nuclear Information System (INIS)

The determination of extracellular galactosyl transferase (EC 2.4.1.38) activity in human intestinal tissue by assessment of the incorporation of label after incubation with UDP[3H]galactose was evaluated. Intestinal biopsy specimens were incubated with membrane-permeable L-[1-14C]fucose and non-permeable UDP-D-[6-3H]galactose (UDP[3H]Gal). Comparison of the amounts of 3H- and 14C-label incorporated into subcellular fractions showed uptake and incorporation of galactose formed by the hydrolysis of UDP[3H]Gal by brush-border enzymes. The results indicate that incorporation of galactose after incubation of the tissue with UDP[3H]Gal is not exclusively attributable to extracellular galactosyl transferase. (Auth.)

1981-01-22

232

Differential effects of flavonoids on barrier integrity in human intestinal Caco-2 cells.  

UK PubMed Central (United Kingdom)

Flavonoids, present in fruits, vegetables, and teas, provide beneficial effects for our health. We investigated the effect of a number of flavonoids on tight junction (TJ) barrier integrity in human intestinal Caco-2 cells. Transepithelial electrical resistance (TER; a TJ integrity marker) across cell monolayers was measured in cells incubated with flavonoids for 24 h. Chrysin decreased the TER, indicating a decrease in TJ integrity. Daidzein, hesperetin, naringenin, and morin increased the TER, indicating increased TJ integrity. Luteolin and genistein increased or normalized the TER after a transient decrease. Immunoblot analysis revealed that these changes in TER were caused by modification of the cytoskeletal association and expression of TJ proteins, zonula occludens (ZO)-1, ZO-2, occludin, junctional adhesion molecule-1, and/or claudins. Our results suggest that various flavonoids participate in the regulation of intestinal TJ barrier integrity and that this regulation may partially contribute to the flavonoid-mediated biological effects on our health.

Noda S; Tanabe S; Suzuki T

2012-05-01

233

Differential effects of flavonoids on barrier integrity in human intestinal Caco-2 cells.  

Science.gov (United States)

Flavonoids, present in fruits, vegetables, and teas, provide beneficial effects for our health. We investigated the effect of a number of flavonoids on tight junction (TJ) barrier integrity in human intestinal Caco-2 cells. Transepithelial electrical resistance (TER; a TJ integrity marker) across cell monolayers was measured in cells incubated with flavonoids for 24 h. Chrysin decreased the TER, indicating a decrease in TJ integrity. Daidzein, hesperetin, naringenin, and morin increased the TER, indicating increased TJ integrity. Luteolin and genistein increased or normalized the TER after a transient decrease. Immunoblot analysis revealed that these changes in TER were caused by modification of the cytoskeletal association and expression of TJ proteins, zonula occludens (ZO)-1, ZO-2, occludin, junctional adhesion molecule-1, and/or claudins. Our results suggest that various flavonoids participate in the regulation of intestinal TJ barrier integrity and that this regulation may partially contribute to the flavonoid-mediated biological effects on our health. PMID:22506771

Noda, Sakino; Tanabe, Soichi; Suzuki, Takuya

2012-04-24

234

Transitional B cell subsets in human bone marrow.  

UK PubMed Central (United Kingdom)

B cells originate from precursors in the bone marrow, and the first cells which migrate to the peripheral blood have been classified as 'transitional B cells'. Transitional B cells have been characterized in human blood with stage 1 (T1) and stage 2 (T2) subsets being proposed. In the present study, 27 normal human bone marrow samples were analysed for transitional B cell markers by eight-colour flow cytometry. T1 transitional B cells (CD45(+)CD19(+)CD10(+)IgM(+)IgD(lo)) and T2 transitional B cells (CD45(+)CD19(+)CD10(+)IgM(+)IgD(+)) were identified in normal bone marrow samples at a mean frequency of 3·2 and 3·1% of total B lineage cells, respectively. A majority of the bone marrow transitional B cells were CD24(hi)CD38(hi) , the phenotype of blood transitional B cells. Consistent with recent peripheral blood data, T2 B cells had a significantly higher CD21 expression compared with T1 B cells (72·4 versus 40·9%) in the bone marrow. These data raise the possibility that transitional B cells are capable of differentiating from T1 to T2 B cells within the bone marrow. Furthermore, transitional cells at either stages 1 or 2 might be capable of migrating out of the bone marrow.

Agrawal S; Smith SA; Tangye SG; Sewell WA

2013-10-01

235

Transitional B cell subsets in human bone marrow.  

Science.gov (United States)

B cells originate from precursors in the bone marrow, and the first cells which migrate to the peripheral blood have been classified as 'transitional B cells'. Transitional B cells have been characterized in human blood with stage 1 (T1) and stage 2 (T2) subsets being proposed. In the present study, 27 normal human bone marrow samples were analysed for transitional B cell markers by eight-colour flow cytometry. T1 transitional B cells (CD45(+) CD19(+) CD10(+) IgM(+) IgD(lo) ) and T2 transitional B cells (CD45(+) CD19(+) CD10(+) IgM(+) IgD(+) ) were identified in normal bone marrow samples at a mean frequency of 3·2 and 3·1% of total B lineage cells, respectively. A majority of the bone marrow transitional B cells were CD24(hi) CD38(hi) , the phenotype of blood transitional B cells. Consistent with recent peripheral blood data, T2 B cells had a significantly higher CD21 expression compared with T1 B cells (72·4 versus 40·9%) in the bone marrow. These data raise the possibility that transitional B cells are capable of differentiating from T1 to T2 B cells within the bone marrow. Furthermore, transitional cells at either stages 1 or 2 might be capable of migrating out of the bone marrow. PMID:23731328

Agrawal, S; Smith, S A B C; Tangye, S G; Sewell, W A

2013-10-01

236

Human intestinal acyl-CoA synthetase 5 is sensitive to the inhibitor triacsin C  

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Full Text Available AIM: To investigate whether human acyl-CoA synthetase 5 (ACSL5) is sensitive to the ACSL inhibitor triacsin C. METHODS: The ACSL isoforms ACSL1 and ACSL5 from rat as well as human ACSL5 were cloned and recombinantly expressed as 6xHis-tagged enzymes. Ni2+-affinity purified recombinant enzymes were assayed at pH 7.5 or pH 9.5 in the presence or absence of triacsin C. In addition, ACSL5 transfected CaCo2 cells and intestinal human mucosa were monitored. ACSL5 expression in cellular systems was verified using Western blot and immunofluorescence. The ACSL assay mix included TrisHCl (pH 7.4), ATP, CoA, EDTA, DTT, MgCl2, [9,10-3H] palmitic acid, and triton X-100. The 200 ?L reaction was initiated with the addition of solubilized, purified recombinant proteins or cellular lysates. Reactions were terminated after 10, 30 or 60 min of incubation with Doles medium. RESULTS: Expression of soluble recombinant ACSL proteins was found after incubation with isopropyl beta-D-1-thiogalactopyranoside and after ultracentrifugation these were further purified to near homogeneity with Ni2+-affinity chromatography. Triacsin C selectively and strongly inhibited recombinant human ACSL5 protein at pH 7.5 and pH 9.5, as well as recombinant rat ACSL1 (sensitive control), but not recombinant rat ACSL5 (insensitive control). The IC50 for human ACSL5 was about 10 ?mol/L. The inhibitory triacsin C effect was similar for different incubation times (10, 30 and 60 min) and was not modified by the N- or C-terminal location of the 6xHis-tag. In order to evaluate ACSL5 sensitivity to triacsin C in a cellular environment, stable human ACSL5 CaCo2 transfectants and mechanically dissected normal human intestinal mucosa with high physiological expression of ACSL5 were analyzed. In both models, ACSL5 peak activity was found at pH 7.5 and pH 9.5, corresponding to the properties of recombinant human ACSL5 protein. In the presence of triacsin C (25 ?mol/L), total ACSL activity was dramatically diminished in human ACSL5 transfectants as well as in ACSL5-rich human intestinal mucosa. CONCLUSION: The data strongly indicate that human ACSL5 is sensitive to triacsin C and does not compensate for other triacsin C-sensitive ACSL isoforms.

Elke Kaemmerer; Anne Peuscher; Andrea Reinartz; Christian Liedtke; Ralf Weiskirchen; Jürgen Kopitz; Nikolaus Gassler

2011-01-01

237

The mechanisms of sodium absorption in the human small intestine.  

UK PubMed Central (United Kingdom)

The present studies were designed to characterize sodium transport in the jejunum and ileum of humans with respect to the effects of water flow, sodium concentration, addition of glucose and galactose, and variations in aniomic composition of luminal fluid. In the ileum, sodium absorption occurred against very steep electrochemical gradients (110 mEq/liter, 5-15 mv), was unaffected by the rate or direction of water flow, and was not stimulated by addition of glucose, galactose, or bicarbonate. These findings led to the conclusion that there is an efficiently active sodium transport across a membrane that is relatively impermeable to sodium. In contrast, jejunal sodium (chloride) absorption can take place against only the modest concentration gradient of 13 mEq/liter, was dramatically influenced by water movement, and was stimulated by addition of glucose, galactose, and bicarbonate. The stimulatory effect of glucose and galactose was evident even when net water movement was inhibited to zero by mannitol. These observations led to the conclusion that a small fraction of jejunal sodium absorption was mediated by active transport coupled either to active absorption of bicarbonate or active secretion of hydrogen ions. The major part of sodium absorption, i.e. sodium chloride absorption, appeared to be mediated by a process of bulk flow of solution along osmotic pressure gradients. The stimulatory effect of glucose and galactose, even at zero water flow, was explained by a model in which the active transport of monosaccharide generates a local osmotic force for the absorption of solution (NaCl and water) from the jejunal lumen, which, in the presence of mannitol, is counterbalanced by a reverse flow of pure solvent (H(2)O) through a parallel set of channels which are impermeable to sodium. Support for the model was obtained by the demonstration that glucose and bicarbonate stimulated the absorption of the nonactively transported solute urea even when net water flow was maintained at zero by addition of mannitol to luminal contents.

Fordtran JS; Rector FC Jr; Carter NW

1968-04-01

238

Tea Catechin Auto-oxidation Dimers are Accumulated and Retained by Caco-2 Human Intestinal Cells  

Science.gov (United States)

Despite the presence of bioactive catechin B-ring auto-oxidation dimers in tea, little is known regarding their absorption in humans. Our hypothesis for this research is that catechin auto-oxidation dimers are present in teas and are absorbable by human intestinal epithelial cells. Dimers [theasinensins (THSNs) and P-2 analogs) were quantified in commercial teas by HPLC-MS. (?)-Epigallocatechin (EGC) and (?)-epigallocatechin gallate (EGCG) homodimers were present at 10–43 and 0–62 µmol/g leaf, respectively. EGC-EGCG heterodimers were present at 0–79 µmol/g. The potential intestinal absorption of these dimers was assessed using Caco-2 intestinal cells. Catechin monomers and dimers were detected in cells exposed to media containing monomers and preformed dimers. Accumulation of dimers was significantly greater than monomers from test media. Three h accumulation of EGC and EGCG was 0.19– 0.55% and 1.24–1.35% respectively. Comparatively, 3h accumulation of the EGC P-2 analog, and THSNs C/E was 0.89 ± 0.28% and 1.53 ± 0.36%. Accumulation of P-2, and THSNs A/D was 6.93 ± 2.1%, and 10.1 ± 3.6%. EGCG-EGC heterodimer P-2 analog, and THSN B 3h accumulation was 4.87 ± 2.2%, and 4.65 ± 2.8% respectively. One h retention of P-2, and THSNs A/D was 171 ± 22%, and 29.6 ± 9.3% of accumulated amount suggesting intracellular oxidative conversion of THSNs to P-2. These data suggest that catechin dimers present in the gut lumen may be readily absorbed by intestinal epithelium.

Neilson, Andrew P.; Song, Brian J.; Sapper, Teryn N.; Bomser, Joshua A.; Ferruzzi, Mario G.

2010-01-01

239

Tea catechin auto-oxidation dimers are accumulated and retained by Caco-2 human intestinal cells.  

UK PubMed Central (United Kingdom)

Despite the presence of bioactive catechin B-ring auto-oxidation dimers in tea, little is known regarding their absorption in humans. Our hypothesis for this research is that catechin auto-oxidation dimers are present in teas and are absorbable by human intestinal epithelial cells. Dimers (theasinensins [THSNs] and P-2 analogs) were quantified in commercial teas by high-performance liquid chromatography-mass spectrometry. (-)-Epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG) homodimers were present at 10 to 43 and 0 to 62 mumol/g leaf, respectively. The EGC-EGCG heterodimers were present at 0 to 79 mumol/g. The potential intestinal absorption of these dimers was assessed using Caco-2 intestinal cells. Catechin monomers and dimers were detected in cells exposed to media containing monomers and preformed dimers. Accumulation of dimers was significantly greater than monomers from test media. Three-hour accumulation of EGC and EGCG was 0.19% to 0.55% and 1.24% to 1.35%, respectively. Comparatively, 3-hour accumulation of the EGC P-2 analog and THSNs C/E was 0.89% +/- 0.28% and 1.53% +/- 0.36%, respectively. Accumulation of P-2 and THSNs A/D was 6.93% +/- 2.1% and 10.1% +/- 3.6%, respectively. The EGCG-EGC heterodimer P-2 analog and THSN B 3-hour accumulation was 4.87% +/- 2.2% and 4.65% +/- 2.8%, respectively. One-hour retention of P-2 and THSNs A/D was 171% +/- 22% and 29.6% +/- 9.3% of accumulated amount, respectively, suggesting intracellular oxidative conversion of THSNs to P-2. These data suggest that catechin dimers present in the gut lumen may be readily absorbed by intestinal epithelium.

Neilson AP; Song BJ; Sapper TN; Bomser JA; Ferruzzi MG

2010-05-01

240

Transitional Human Rights Hope For Egypt and the Region  

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Full Text Available Though the Egyptian civilization is approximately 7,000 years old, it may still be considered a young nation in terms of human rights appreciation. It is a country beginning a drastic transition, and among the elements of Egyptian life starting to change is a new found hope for an enshrinement of basic human rights that have previously never been made available for the majority of the Egyptian population. It is my contention that the Egyptian people’s reaction to the consistent and flagrant human rights abuses of the Mubarak regime was the catalyst that started the revolution of 2011. I will further discuss the transitional nature of the human rights awakening in Egypt by comparing their current metamorphosis to that of the somewhat recently transitioned nations of the Czech Republic, South Africa and Tunisia.Human rights violations are oftentimes unusually severe in countries going through a time of political, economic and social transition. Improving human rights standards and practices in transitional societies should be considered important for the good of the entire region and my paper attempts to direct the discussion of how a transitional human rights regime can become positively entrenched in the psyche of the newly awakened nation and region. Egypt now stands at a precipice where it must decide for itself if it wants to become a modern nation where rights for all are protected or if it will fall in line with the often abysmal human rights expectations of other nations in the region. With the disappointing experiences of the Mubarak regime still alive in the minds of the Egyptian people, my paper argues that we can remain cautiously optimistic that in the future, human rights will be more greatly respected than in the past. I argue that with the proper attention and support from the international community the growing pains of a free Egypt will be minimal while the rewards can be colossal.

Scott James Meyer

2011-01-01

 
 
 
 
241

Transition as a Concept of European Human Rights Law  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The social, economic and political transition in Central and Eastern European States marked the past two decades of European human rights law. It accounted for a specific circumstance in which the protection of Convention rights had to be ensured. The law of the European Convention on Human Rights r...

Varju Márton (1977-) (jogász)

242

Human gut-on-a-chip inhabited by microbial flora that experiences intestinal peristalsis-like motions and flow.  

Science.gov (United States)

Development of an in vitro living cell-based model of the intestine that mimics the mechanical, structural, absorptive, transport and pathophysiological properties of the human gut along with its crucial microbial symbionts could accelerate pharmaceutical development, and potentially replace animal testing. Here, we describe a biomimetic 'human gut-on-a-chip' microdevice composed of two microfluidic channels separated by a porous flexible membrane coated with extracellular matrix (ECM) and lined by human intestinal epithelial (Caco-2) cells that mimics the complex structure and physiology of living intestine. The gut microenvironment is recreated by flowing fluid at a low rate (30 ?L h(-1)) producing low shear stress (0.02 dyne cm(-2)) over the microchannels, and by exerting cyclic strain (10%; 0.15 Hz) that mimics physiological peristaltic motions. Under these conditions, a columnar epithelium develops that polarizes rapidly, spontaneously grows into folds that recapitulate the structure of intestinal villi, and forms a high integrity barrier to small molecules that better mimics whole intestine than cells in cultured in static Transwell models. In addition, a normal intestinal microbe (Lactobacillus rhamnosus GG) can be successfully co-cultured for extended periods (>1 week) on the luminal surface of the cultured epithelium without compromising epithelial cell viability, and this actually improves barrier function as previously observed in humans. Thus, this gut-on-a-chip recapitulates multiple dynamic physical and functional features of human intestine that are critical for its function within a controlled microfluidic environment that is amenable for transport, absorption, and toxicity studies, and hence it should have great value for drug testing as well as development of novel intestinal disease models. PMID:22434367

Kim, Hyun Jung; Huh, Dongeun; Hamilton, Geraldine; Ingber, Donald E

2012-03-20

243

Human intestinal parasites in non-biting synanthropic flies in Ogun State, Nigeria.  

Science.gov (United States)

Filth-feeding and breeding, non-biting synanthropic flies have been incriminated in the dissemination of human enteropathogens in the environment. This study determined the species of non-biting synanthropic flies associated with four filthy sites in Ilishan, Ogun State, southwest Nigeria, and assessed their potentials for mechanical transmission of human intestinal parasites. 7190 flies identified as Musca domestica (33.94%), Chrysomya megacephala (26.01%), Musca sorbens (23.23%), Lucilia cuprina (8.76%), Calliphora vicina (4.59%), Sarcophaga sp. (2.78%) and Fannia scalaris (0.70%) were examined for human intestinal parasites by the formol-ether concentration and modified Ziehl-Neelsen techniques. Eggs of the following parasites: Ascaris lumbricoides (34.08%), Trichuris trichiura (25.87%), hookworms (20.45%), Taenia sp. (2.36%), Hymenolepis nana (1.11%), Enterobius vermicularis (0.56%), Strongyloides stercoralis (larvae; 3.89%) and cysts of Entamoeba histolytica/dispar (27.26%), Entamoeba coli (22.67%), Giardia lamblia (3.34%) and Cryptosporidium sp. (1.81%) were isolated from the body surfaces and or gut contents of 75.24% of 719 pooled fly batches. The helminths A. lumbricoides and T. trichiura and the protozoans, E. histolytica/dispar and E. coli were the dominant parasites detected, both on body surfaces and in the gut contents of flies. C. megacephala was the highest carrier of parasites (diversity and number). More parasites were isolated from the gut than from body surfaces (P < 0.05). Flies from soiled ground often carried more parasites than those from abattoir, garbage or open-air market. Synanthropic fly species identified in this study can be of potential epidemiological importance as mechanical transmitters of human intestinal parasites acquired naturally from filth and carried on their body surfaces and or in the gut, because of their vagility and feeding mechanisms. PMID:23290716

Adenusi, Adedotun Adesegun; Adewoga, Thomas O Sunday

2013-01-03

244

Human intestinal parasites in non-biting synanthropic flies in Ogun State, Nigeria.  

UK PubMed Central (United Kingdom)

Filth-feeding and breeding, non-biting synanthropic flies have been incriminated in the dissemination of human enteropathogens in the environment. This study determined the species of non-biting synanthropic flies associated with four filthy sites in Ilishan, Ogun State, southwest Nigeria, and assessed their potentials for mechanical transmission of human intestinal parasites. 7190 flies identified as Musca domestica (33.94%), Chrysomya megacephala (26.01%), Musca sorbens (23.23%), Lucilia cuprina (8.76%), Calliphora vicina (4.59%), Sarcophaga sp. (2.78%) and Fannia scalaris (0.70%) were examined for human intestinal parasites by the formol-ether concentration and modified Ziehl-Neelsen techniques. Eggs of the following parasites: Ascaris lumbricoides (34.08%), Trichuris trichiura (25.87%), hookworms (20.45%), Taenia sp. (2.36%), Hymenolepis nana (1.11%), Enterobius vermicularis (0.56%), Strongyloides stercoralis (larvae; 3.89%) and cysts of Entamoeba histolytica/dispar (27.26%), Entamoeba coli (22.67%), Giardia lamblia (3.34%) and Cryptosporidium sp. (1.81%) were isolated from the body surfaces and or gut contents of 75.24% of 719 pooled fly batches. The helminths A. lumbricoides and T. trichiura and the protozoans, E. histolytica/dispar and E. coli were the dominant parasites detected, both on body surfaces and in the gut contents of flies. C. megacephala was the highest carrier of parasites (diversity and number). More parasites were isolated from the gut than from body surfaces (P < 0.05). Flies from soiled ground often carried more parasites than those from abattoir, garbage or open-air market. Synanthropic fly species identified in this study can be of potential epidemiological importance as mechanical transmitters of human intestinal parasites acquired naturally from filth and carried on their body surfaces and or in the gut, because of their vagility and feeding mechanisms.

Adenusi AA; Adewoga TO

2013-05-01

245

Developmental changes in vasoactive intestinal polypeptide immunoreactivity in the human paravertebral ganglia.  

UK PubMed Central (United Kingdom)

Vasoactive intestinal polypeptide (VIP) belongs to the glucagon-secretin family of polypeptides and possesses numerous functions. Its existence in the mammalian central and peripheral nervous system has been widely documented. However, there are no reports on the developmental aspects of VIP-like immunoreactivity (VIP-IR) in the human postganglionic sympathetic neurons. In this study the availability and distribution of vasoactive intestinal polypeptide has been localized in human stellate ganglia neurons and nerve fibers from neonates, children and adults using the immunohistochemical method. In neonatal ganglia VIP-immunoreactive postganglionic neurons were revealed in a marked population compared to others age-groups. These nerve cells are both small and large in size and are distributed in small clusters or singly in the area of ganglia sections. In children, VIP-IR in ganglionic neurons decreases. In adult stellate ganglia, VIP-immunoreactive postganglionic neurons rarely occur. In ganglia of an individual human only varicosities of VIP-positive nerve fibers were observed. These results provide the age-dependent reduction of VIP-like immunoreactivity in human stellate ganglia neurons and suggest the different role of this peptide in the function of sympathetic ganglia neurons with age.

Roudenok V; Kühnel W; Rogov Y; Nerovnja A

1999-12-01

246

Sulphomucin-secreting intestinal metaplasia in the human gastric mucosa. An association with intestinal-type gastric carcinoma.  

UK PubMed Central (United Kingdom)

Sixty-three gastrectomy specimens (21 with early intestinal type carcinoma, 21 with early diffuse carcinoma, and 21 with benign nonneoplastic lesions) were examined histochemically to determine the distribution of intestinal metaplasia (IM), particularly the sulphomucin-secreting type (Type IIB IM). The frequency and distribution of Type IIB IM were similar, irrespective of the disease, when age of the patient was matched and if the extension of the IM was similar. Type IIB IM was usually observed in the mucosa along the lesser curvature of the lower portion of the stomach, particularly in elderly patients and was mainly located in the deeper foveolae and intermingled with or transient to those in other types of IM. These findings suggest that a casual relationship between Type IIB IM and intestinal type carcinoma is dubious.

Matsukuma A; Mori M; Enjoji M

1990-08-01

247

Sulphomucin-secreting intestinal metaplasia in the human gastric mucosa. An association with intestinal-type gastric carcinoma.  

Science.gov (United States)

Sixty-three gastrectomy specimens (21 with early intestinal type carcinoma, 21 with early diffuse carcinoma, and 21 with benign nonneoplastic lesions) were examined histochemically to determine the distribution of intestinal metaplasia (IM), particularly the sulphomucin-secreting type (Type IIB IM). The frequency and distribution of Type IIB IM were similar, irrespective of the disease, when age of the patient was matched and if the extension of the IM was similar. Type IIB IM was usually observed in the mucosa along the lesser curvature of the lower portion of the stomach, particularly in elderly patients and was mainly located in the deeper foveolae and intermingled with or transient to those in other types of IM. These findings suggest that a casual relationship between Type IIB IM and intestinal type carcinoma is dubious. PMID:2386900

Matsukuma, A; Mori, M; Enjoji, M

1990-08-15

248

Beneficial effect of recombinant human growth hormone on the intestinal mucosa barrier of septic rats  

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Full Text Available The objective of the present study was to investigate the effects of recombinant human growth hormone (rhGH) on the intestinal mucosa barrier of septic rats and explore its possible mechanism. Female Sprague-Dawley rats were randomized into three groups: control, Escherichia coli-induced sepsis (S) and treatment (T) groups. Groups S and T were subdivided into subgroups 1d and 3d, respectively. Expression of liver insulin-like growth factor-1 (IGF-1) mRNA, Bcl-2 and Bax protein levels and the intestinal Bax/Bcl-2 ratio, and plasma GH and IGF-1 levels were determined. Histological examination of the intestine was performed and bacterial translocation was determined. rhGH significantly attenuated intestinal mucosal injuries and bacterial translocation in septic rats, markedly decreased Bax protein levels, inhibited the decrease of Bcl-2 protein expression and maintained the Bax/Bcl-2 ratio in the intestine. rhGH given after sepsis significantly improved levels of plasma GH (T1d: 1.28 ± 0.24; T3d: 2.14 ± 0.48 µg/L vs S1d: 0.74 ± 0.12; S3d: 0.60 ± 0.18 µg/L; P < 0.05) and IGF-1 (T1d: 168.94 ± 65.67; T3d: 201.56 ± 64.98 µg/L vs S1d: 116.72 ± 13.96; S3d: 107.50 ± 23.53 µg/L; P < 0.05) and expression of liver IGF-1 mRNA (T1d: 0.98 ± 0.20; T3d: 1.76 ± 0.17 vs S1d: 0.38 ± 0.09; S3d: 0.46 ± 0.10; P < 0.05). These findings indicate that treatment with rhGH had beneficial effects on the maintenance of the integrity of the intestinal mucosa barrier in septic rats.

C. Yi; Y. Cao; S.R. Wang; Y.Z. Xu; H. Huang; Y.X. Cui; Y. Huang

2007-01-01

249

Intestinal mucin inhibits adhesion of human enteropathogenic Escherichia coli to HEp-2 cells.  

UK PubMed Central (United Kingdom)

Mucins are complex glycoproteins that cover the intestinal mucosal surface and are thought to provide protection against enteropathogenic infections by preventing bacterial adherence and subsequent colonization, invasion and toxin delivery. The aims of this study was to evaluate the capacity of intestinal mucin to inhibit epithelial cell adhesion by human enteropathogenic Escherichia colI (EPEC). EPEC strain E2348/69 (serotype O127:H6), known to produce a 94-kd epithelia cell-adhesion-mediating outer membrane protein called intimin and known to contain an EPEC adherence factor (EAF) plasmid, and three of its mutants were studied. Crude mucus was obtained from rabbit small-ubtestinal mucosal scrapings. Purified mucins were isolated by serial cesium chloride density gradient ultracentrifugation. Bacterial adhesion to HEp-2 epithelial cell monolayers in the presence of purified intestinal mucins was quantified by recovery of live viable bacteria as colony-forming units. EPEC strain E2348/69 adhesion was inhibited in a concentration-dependent manner by increasing amounts of mucin (adhesion suppressed to <1% by 150 microgram mucin). The relative magnitudes of inhibition of adhesion of E2348/69 and its mutants [JPN15 (EAF plasmid negative), JPN15.96(pMAR7) (intimin negative), and JPN15.96 (intimin negative, EAF plasmid negative)] were similar in the presence of equal amounts of mucin. The presence of the intimin protein and EAF plasmid are not necessary to the proficiency of mucin to inhibit HEp-2 epithelial cell adhesion.

Smith CJ; Kaper JB; Mack DR

1995-10-01

250

Regulation of interleukin-8 secretion in human intestinal epithelial Caco-2 cells by alpha-humulene.  

UK PubMed Central (United Kingdom)

It is well known that various cytokines such as interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha are expressed and secreted from intestinal epithelial cells and that these cytokines affect the immune cells beneath the intestinal epithelial monolayers. As the secretion of these cytokines is likely to be regulated by food-derived substances, we focused on those food substances which regulate the secretion of IL-8 in human intestinal epithelial Caco-2 cells. 72 food samples extracted with 40% ethanol were tested, and the extracts of peppermint and dokudami significantly increased the IL-8 secretion. Among the compounds known to be contained in peppermint and dokudami, alpha-humulene substantially increased the IL-8 secretion.alpha-Humulene had no significant effect on the secretion of such other soluble factors as TNF-alpha, IL-1beta, IL-6, or NGF, suggesting that the effect of alpha-humulene was specific for IL-8 secretion. The expression level of IL-8 mRNA was significantly increased by treating with alpha-humulene. These results suggest that the secretion of IL-8 by alpha-humulene is regulated at the transcriptional level.

Satsu H; Matsuda T; Toshimitsu T; Mori A; Mae T; Tsukagawa M; Kitahara M; Shimizu M

2004-01-01

251

Metabolism of the benzidine-based azo dye Direct Black 38 by human intestinal microbiota  

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Benzidine-based azo dyes are proven mutagens and have been linked to bladder cancer. Previous studies have indicated that their initial reduction is the result of the azo reductase activity of the intestinal microbiota. Metabolism of the benzidine-based dye Direct Black 38 was examined by using a semicontinuous culture system that simulates the lumen of the human large intestine. The system was inoculated with freshly voided feces, and an active flora was maintained as evidenced by volatile fatty acid and gas production. Within 7 days after exposure to the dye, the following metabolites were isolated and identified by gas chromatography - mass spectrometry: benzidine, 4-aminobiphenyl, monoacetylbenzidine, and acetylaminobiphenyl. Benzidine reached its peak level after 24 h, accounting for 39.1% of the added dye. Its level began to decline, and by day 7 the predominant metabolite was acetylaminobiphenyl, which accounted for 51.1% of the parent compound. Formation of the deaminated and N-acetylated analogs of benzidine, which have enhanced mutagenicity and lipophilicity, previously has not been attributed to the intestinal microbiota.

Manning, B.W.; Cerniglia, C.E.; Federle, T.W.

1985-07-01

252

[Evaluation of intestinal pathogenicity of Yersinia spp. strains isolated from human feces  

UK PubMed Central (United Kingdom)

BACKGROUND: Yersinia enterocolitica is a human pathogen which an acts on the intestine by basically enteroinvasive mechanism. Its virulence has been related with the presence of a plasmid of 40-50 MD which codes a series of properties. There are strains of Y. enterocolitica and of other species assimilated to the Y. enterocolitica group which lack the virulence plasmid. In these cases there is a problem in evaluating the pathogenic ability on the intestine of these bacterias when isolated in faeces. METHODS: A study of 30 Yersinia spp. strains including growth in a magnesium oxalate medium, Reg-Congo and agar (CR-MOX), sculine hydrolisis (Sc), pyrazinamidase activity (Pyz) and salicine fermentation (Sal) was performed. In addition, the presence of virulence plasmid (VP) was determined. RESULTS: Twenty-two strains identified as Y. enterocolitica presented the virulence pattern (CR-MOX+, Pyz-, Sal/Sc-) and 21 were VP+. Seven strains isolated were CR-MOX-, Pyz+, Sal/Sc+ and VP- being typed as Y. fredericksenii (6) and Y. kristensenii (1). The remaining strain was CR-MOX- and VP- but Pyz, Sal/Sc were also negative, being identified as Y. enterocolitica. CONCLUSIONS: By the tests referred the authors were able to identify and evaluate the pathogenicity of Yersinia spp. isolated in faeces. These techniques may be used in the microbiology laboratory as a method which aids to evaluate the diagnosis of intestinal infections caused by Yersinia spp.

Carranza R; Torres MJ; Seman M; Pascual A

1993-06-01

253

Extracellular nucleotides inhibit oxalate transport by human intestinal Caco-2-BBe cells through PKC-? activation.  

UK PubMed Central (United Kingdom)

Nephrolithiasis remains a major health problem in Western countries. Seventy to 80% of kidney stones are composed of calcium oxalate, and small changes in urinary oxalate affect risk of kidney stone formation. Intestinal oxalate secretion mediated by the anion exchanger SLC26A6 plays an essential role in preventing hyperoxaluria and calcium oxalate nephrolithiasis, indicating that understanding the mechanisms regulating intestinal oxalate transport is critical for management of hyperoxaluria. Purinergic signaling modulates several intestinal processes through pathways including PKC activation, which we previously found to inhibit Slc26a6 activity in mouse duodenal tissue. We therefore examined whether purinergic stimulation with ATP and UTP affects oxalate transport by human intestinal Caco-2-BBe (C2) cells. We measured [¹?C]oxalate uptake in the presence of an outward Cl? gradient as an assay of Cl?/oxalate exchange activity, ?50% of which is mediated by SLC26A6. We found that ATP and UTP significantly inhibited oxalate transport by C2 cells, an effect blocked by the PKC inhibitor Gö-6983. Utilizing pharmacological agonists and antagonists, as well as PKC-? knockdown studies, we observed that ATP inhibits oxalate transport through the P2Y? receptor, PLC, and PKC-?. Biotinylation studies showed that ATP inhibits oxalate transport by lowering SLC26A6 surface expression. These findings are of potential relevance to pathophysiology of inflammatory bowel disease-associated hyperoxaluria, where supraphysiological levels of ATP/UTP are expected and overexpression of the P2Y? receptor has been reported. We conclude that ATP and UTP inhibit oxalate transport by lowering SLC26A6 surface expression in C2 cells through signaling pathways including the P2Y? purinergic receptor, PLC, and PKC-?.

Amin R; Sharma S; Ratakonda S; Hassan HA

2013-07-01

254

Extracellular nucleotides inhibit oxalate transport by human intestinal Caco-2-BBe cells through PKC-? activation.  

Science.gov (United States)

Nephrolithiasis remains a major health problem in Western countries. Seventy to 80% of kidney stones are composed of calcium oxalate, and small changes in urinary oxalate affect risk of kidney stone formation. Intestinal oxalate secretion mediated by the anion exchanger SLC26A6 plays an essential role in preventing hyperoxaluria and calcium oxalate nephrolithiasis, indicating that understanding the mechanisms regulating intestinal oxalate transport is critical for management of hyperoxaluria. Purinergic signaling modulates several intestinal processes through pathways including PKC activation, which we previously found to inhibit Slc26a6 activity in mouse duodenal tissue. We therefore examined whether purinergic stimulation with ATP and UTP affects oxalate transport by human intestinal Caco-2-BBe (C2) cells. We measured [¹?C]oxalate uptake in the presence of an outward Cl? gradient as an assay of Cl?/oxalate exchange activity, ?50% of which is mediated by SLC26A6. We found that ATP and UTP significantly inhibited oxalate transport by C2 cells, an effect blocked by the PKC inhibitor Gö-6983. Utilizing pharmacological agonists and antagonists, as well as PKC-? knockdown studies, we observed that ATP inhibits oxalate transport through the P2Y? receptor, PLC, and PKC-?. Biotinylation studies showed that ATP inhibits oxalate transport by lowering SLC26A6 surface expression. These findings are of potential relevance to pathophysiology of inflammatory bowel disease-associated hyperoxaluria, where supraphysiological levels of ATP/UTP are expected and overexpression of the P2Y? receptor has been reported. We conclude that ATP and UTP inhibit oxalate transport by lowering SLC26A6 surface expression in C2 cells through signaling pathways including the P2Y? purinergic receptor, PLC, and PKC-?. PMID:23596171

Amin, Ruhul; Sharma, Sapna; Ratakonda, Sireesha; Hassan, Hatim A

2013-04-17

255

Recellularization of acellular human small intestine using bone marrow stem cells.  

UK PubMed Central (United Kingdom)

We aimed to produce an acellular human tissue scaffold with a view to test the possibility of recellularization with bone marrow stem cells to produce a tissue-engineered small intestine (TESI). Human small-bowel specimens (n = 5) were obtained from cadaveric organ donors and treated sequentially with 6% dimethyl sulfoxide in hypotonic buffer, 1% Triton X-100, and DNase. Each small intestine (SI) piece (6 cm) was recellularized with EPCAM+ and CD133+ allogeneic bone marrow stem cells. Histological and molecular analysis demonstrated that after decellularization, all cellular components and nuclear material were removed. Our analysis also showed that the decellularized human SI tissue retained its histoarchitecture with intact villi and major structural proteins. Protein films of common extracellular matrix constituents (collagen I, laminin, and fibronectin) were found in abundance. Furthermore, several residual angiogenic factors were found in the decellularized SI. Following recellularization, we found viable mucin-positive goblet cells, CK18+ epithelial cells in villi adjacent to a muscularis mucosa with ?-actin+ smooth muscle cells, and a high repopulation of blood vessels with CD31+ endothelial cells. Our results show that in the future, such a TESI would be ideal for clinical purposes, because it can be derived from the recipient's own immunocompatible bone marrow cells, thus avoiding the use of immunosuppression.

Patil PB; Chougule PB; Kumar VK; Almström S; Bäckdahl H; Banerjee D; Herlenius G; Olausson M; Sumitran-Holgersson S

2013-04-01

256

Recellularization of acellular human small intestine using bone marrow stem cells.  

Science.gov (United States)

We aimed to produce an acellular human tissue scaffold with a view to test the possibility of recellularization with bone marrow stem cells to produce a tissue-engineered small intestine (TESI). Human small-bowel specimens (n = 5) were obtained from cadaveric organ donors and treated sequentially with 6% dimethyl sulfoxide in hypotonic buffer, 1% Triton X-100, and DNase. Each small intestine (SI) piece (6 cm) was recellularized with EPCAM+ and CD133+ allogeneic bone marrow stem cells. Histological and molecular analysis demonstrated that after decellularization, all cellular components and nuclear material were removed. Our analysis also showed that the decellularized human SI tissue retained its histoarchitecture with intact villi and major structural proteins. Protein films of common extracellular matrix constituents (collagen I, laminin, and fibronectin) were found in abundance. Furthermore, several residual angiogenic factors were found in the decellularized SI. Following recellularization, we found viable mucin-positive goblet cells, CK18+ epithelial cells in villi adjacent to a muscularis mucosa with ?-actin+ smooth muscle cells, and a high repopulation of blood vessels with CD31+ endothelial cells. Our results show that in the future, such a TESI would be ideal for clinical purposes, because it can be derived from the recipient's own immunocompatible bone marrow cells, thus avoiding the use of immunosuppression. PMID:23486834

Patil, Pradeep B; Chougule, Priti B; Kumar, Vijay K; Almström, Stefan; Bäckdahl, Henrik; Banerjee, Debashish; Herlenius, Gustaf; Olausson, Michael; Sumitran-Holgersson, Suchitra

2013-03-13

257

Smoking Cessation Induces Profound Changes in the Composition of the Intestinal Microbiota in Humans  

Science.gov (United States)

Background The human intestinal microbiota is a crucial factor in the pathogenesis of various diseases, such as metabolic syndrome or inflammatory bowel disease (IBD). Yet, knowledge about the role of environmental factors such as smoking (which is known to influence theses aforementioned disease states) on the complex microbial composition is sparse. We aimed to investigate the role of smoking cessation on intestinal microbial composition in 10 healthy smoking subjects undergoing controlled smoking cessation. Methods During the observational period of 9 weeks repetitive stool samples were collected. Based on abundance of 16S rRNA genes bacterial composition was analysed and compared to 10 control subjects (5 continuing smokers and 5 non-smokers) by means of Terminal Restriction Fragment Length Polymorphism analysis and high-throughput sequencing. Results Profound shifts in the microbial composition after smoking cessation were observed with an increase of Firmicutes and Actinobacteria and a lower proportion of Bacteroidetes and Proteobacteria on the phylum level. In addition, after smoking cessation there was an increase in microbial diversity. Conclusions These results indicate that smoking is an environmental factor modulating the composition of human gut microbiota. The observed changes after smoking cessation revealed to be similar to the previously reported differences in obese compared to lean humans and mice respectively, suggesting a potential pathogenetic link between weight gain and smoking cessation. In addition they give rise to a potential association of smoking status and the course of IBD.

Biedermann, Luc; Zeitz, Jonas; Mwinyi, Jessica; Sutter-Minder, Eveline; Rehman, Ateequr; Ott, Stephan J.; Steurer-Stey, Claudia; Frei, Anja; Frei, Pascal; Scharl, Michael; Loessner, Martin J.; Vavricka, Stephan R.; Fried, Michael; Schreiber, Stefan; Schuppler, Markus; Rogler, Gerhard

2013-01-01

258

Smoking cessation induces profound changes in the composition of the intestinal microbiota in humans.  

UK PubMed Central (United Kingdom)

BACKGROUND: The human intestinal microbiota is a crucial factor in the pathogenesis of various diseases, such as metabolic syndrome or inflammatory bowel disease (IBD). Yet, knowledge about the role of environmental factors such as smoking (which is known to influence theses aforementioned disease states) on the complex microbial composition is sparse. We aimed to investigate the role of smoking cessation on intestinal microbial composition in 10 healthy smoking subjects undergoing controlled smoking cessation. METHODS: During the observational period of 9 weeks repetitive stool samples were collected. Based on abundance of 16S rRNA genes bacterial composition was analysed and compared to 10 control subjects (5 continuing smokers and 5 non-smokers) by means of Terminal Restriction Fragment Length Polymorphism analysis and high-throughput sequencing. RESULTS: Profound shifts in the microbial composition after smoking cessation were observed with an increase of Firmicutes and Actinobacteria and a lower proportion of Bacteroidetes and Proteobacteria on the phylum level. In addition, after smoking cessation there was an increase in microbial diversity. CONCLUSIONS: These results indicate that smoking is an environmental factor modulating the composition of human gut microbiota. The observed changes after smoking cessation revealed to be similar to the previously reported differences in obese compared to lean humans and mice respectively, suggesting a potential pathogenetic link between weight gain and smoking cessation. In addition they give rise to a potential association of smoking status and the course of IBD.

Biedermann L; Zeitz J; Mwinyi J; Sutter-Minder E; Rehman A; Ott SJ; Steurer-Stey C; Frei A; Frei P; Scharl M; Loessner MJ; Vavricka SR; Fried M; Schreiber S; Schuppler M; Rogler G

2013-01-01

259

Transepithelial transport of ambroxol hydrochloride across human intestinal Caco-2 cell monolayers.  

Science.gov (United States)

This study aimed i) to characterize the transepithelial transport of the mucolytic agent ambroxol hydrochloride across the intestinal barrier, ii) to classify the ambroxol according to Biopharmaceutics Classification System (BCS) and iii) to predict ambroxol absorption in humans. Transport of ambroxol (100, 300 and 1000 micromol/l) was studied in a human colon carcinoma cell line Caco-2 in apical to basolateral and basolateral to apical direction, under iso-pH 7.4 and pH-gradient (6 vs. 7.4) conditions. The relative contribution of the paracellular route was estimated using Ca2+-free transport medium. Ambroxol samples from receiver compartments were analysed by HPLC with UV detection (242 nm). Results showed that ambroxol transport is linear with time, pH-dependent and direction-independent, displays non-saturable (first-order) kinetics. Thus, the transport seems to be transcellular mediated by passive diffusion. Estimated high solubility and high permeability (P(app) = 45 x 10(-6) cm/s) of ambroxol rank it among well absorbed compounds and class I of BCS. It can be expected that the oral dose fraction of ambroxol absorbed in human intestine is high. PMID:20037197

Stetinová, Vera; Smetanová, Libuse; Kholová, Dagmar; Svoboda, Zbynek; Kvetina, Jaroslav

2009-09-01

260

Transepithelial transport of ambroxol hydrochloride across human intestinal Caco-2 cell monolayers.  

UK PubMed Central (United Kingdom)

This study aimed i) to characterize the transepithelial transport of the mucolytic agent ambroxol hydrochloride across the intestinal barrier, ii) to classify the ambroxol according to Biopharmaceutics Classification System (BCS) and iii) to predict ambroxol absorption in humans. Transport of ambroxol (100, 300 and 1000 micromol/l) was studied in a human colon carcinoma cell line Caco-2 in apical to basolateral and basolateral to apical direction, under iso-pH 7.4 and pH-gradient (6 vs. 7.4) conditions. The relative contribution of the paracellular route was estimated using Ca2+-free transport medium. Ambroxol samples from receiver compartments were analysed by HPLC with UV detection (242 nm). Results showed that ambroxol transport is linear with time, pH-dependent and direction-independent, displays non-saturable (first-order) kinetics. Thus, the transport seems to be transcellular mediated by passive diffusion. Estimated high solubility and high permeability (P(app) = 45 x 10(-6) cm/s) of ambroxol rank it among well absorbed compounds and class I of BCS. It can be expected that the oral dose fraction of ambroxol absorbed in human intestine is high.

Stetinová V; Smetanová L; Kholová D; Svoboda Z; Kvetina J

2009-09-01

 
 
 
 
261

miR-200b inhibits TGF-?1-induced epithelial-mesenchymal transition and promotes growth of intestinal epithelial cells.  

UK PubMed Central (United Kingdom)

Inflammatory bowel disease (IBD), which consists of Crohn's disease (CD) and ulcerative colitis (UC), is a chronic, inflammatory disorder of the gastro-intestinal tract with unknown etiology. Current evidence suggests that intestinal epithelial cells (IECs) is prominently linked to the pathogenesis of IBD. Therefore, maintaining the intact of epithelium has potential roles in improving pathophysiology and clinical outcomes of IBD. MicroRNAs (miRNAs) act as post-transcriptional gene regulators and regulate many biological processes, including embryonal development, cell differentiation, apoptosis and proliferation. In this study, we found that miR-200b decreased significantly in inflamed mucosa of IBD, especially for UC, when compared with their adjacent normal tissue. Simultaneously, we also found that the genes of E-cadherin and cyclin D1 were reduced significantly and correlated positively to the miR-200b. In addition, the upregulation of transforming growth factor-beta 1 (TGF-?1) was inversely correlated to the miR-200b in IBD. To investigate the possible roles of miR-200b in IECs maintaining, we used TGF-?1 to induce epithelial-mesenchymal transition (EMT) in IEC-6 initially. After sustained over-expressing miR-200b in IEC-6, the EMT was inhibited significantly that was characterized by downregulation of vimentin and upregulation of E-cadherin. Furthermore, we found that miR-200b enhanced E-cadherin expression through targeting of ZEB1, which encode transcriptional repressors of E-cadherin. SMAD2 was found to act as a target of miR-200b with direct evidence that miR-200b binding to the 3' UTR of SAMD2 and the ability of miR-200b to repress SMAD2 protein expression. With SMAD2 depletion, the expression of vimentin decreased correspondingly, which suggested miR-200b might reduce vimentin through regulating the SMAD2. With endogenous over-expression of miR-200b, the proliferation of IEC-6 cells increased significantly by increasing S-phase entry and promoting expression of the protein cyclin D1. Summarily, our study suggested a potential role for mir-200b in maintaining intact of intestinal epithelium through inhibiting EMT and promoting proliferation of IECs.

Chen Y; Xiao Y; Ge W; Zhou K; Wen J; Yan W; Wang Y; Wang B; Qu C; Wu J; Xu L; Cai W

2013-01-01

262

The human TLR4 variant D299G mediates inflammation-associated cancer progression in the intestinal epithelium.  

UK PubMed Central (United Kingdom)

Homeostatic TLR4 signaling protects the intestinal epithelium in health. Evidence suggests that perturbed TLR4 signaling is linked to carcinogenesis. We have recently demonstrated that the common human TLR4 variant D299G exerts pro-inflammatory effects and drives malignant tumor progression in human colon cancer.

Cario E

2013-07-01

263

Utilização do método videolaparoscopico na reconstituição do trânsito intestinal após a operação de Hartmann/ The use of videolaparoscopic approach in the intestinal transit restoration after Hartmann's procedure  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O objetivo é apresentar a padronização da técnica operatória e os resultados obtidos com a utilização do acesso videolaparoscópico na reconstituição do trânsito intestinal em pacientes previamente submetidos à operação de Hartmann por causas diversas. Foram analisados prospectivamente 32 pacientes, no período de dezembro de 1991 a junho de 1997, com distribuição semelhante com relação ao sexo e com idade média de 42,4 anos. Todos os pacientes foram sub (more) metidos ao mesmo preparo pré-operatório e à mesma técnica cirúrgica. Ocorreram três (9,3%) complicações transoperatórias. Uma (3,1 %) anastomose mecânica incompleta, necessitando de endossutura manual, uma (3,1 %) laceração do reto com o grampeador mecânico e uma (3,1 %) lesão da artéria epigástrica direita. Ocorreram ainda três (9,3%) conversões, sendo uma (3,1 %) devido à laceração do reto com o grampeador mecânico, outra (3.1 %) pela invasão tumoral na pelve e outra (3,1 %) pela presença de excessivas aderências intraperitoneais. O tempo operatório variou de 30 a 240 minutos, na média de 126,2 minutos (2,1 horas). A evolução clínica pós-operatória foi satisfatória. Nove (31,0%) pacientes não referiram dor, enquanto 13 (44,8%) a referiram em pequena intensidade, e apenas sete (24,0%) queixaram-se de dor com maior intensidade. A dieta líquida via oral foi instituída no período médio de 1,6 dias, e a primeira evacuação ocorreu na média de 3,2 dias de pós-operatório. O período médio de hospitalização foi de 4,7 dias. Ocorreram complicações pós-operatórias em oito (27,5%) pacientes. Duas (6,8%) infecções da ferida do estoma, dois pacientes (6,8%) com dor no ombro direito, uma (3,4%) deiscência de anastomose, um (3,4%) caso de peritonite por provável contaminação do material cirúrgico, uma coleção líquida pélvica e uma hérnia incisional. Em conclusão, a reconstituição do trânsito intestinal por videolaparoscopia apresentou-se segura e eficaz, podendo constituir-se no método cirúrgico de escolha, pois foi utilizada com sucesso em 90,6% dos pacientes. Abstract in english We present the operative technique and the results of the laparoscopic approach for Hartmann's colostomy reversal. Thirty two patients were prospectively analysed from december 1991 to june 1997. They presented a similar incidence regarding sex distribution, and a median age of 42.4 years old. Ali patients underwent the same preoperative preparation and operative technique. Three (9.3%) intraoperative complications were observed: an uncompleted anastomosis (3.1%), requiri (more) ng an endosuture, a rectal perforation by the mechanical stapler and a right epigastric artery lesion. There were convertion to open surgery in three (9.3%) patients: one (3.1%) due to rectal perforation by the mechanical staple1; one (3.1%) for tumoral pelvic invasion and another because of excessive intra-peritoneal adhesions. Operative time varied from 30 to 240 minutes, with a mean time of 126;2 minutes. Nine (31.0%) patients didn't present pain, while 13 (44.8%) referred minimal pain and seven (24.0%) complained severe pain. Oral liquid diet intake occurred within a mean time of 1.6 days and the first evacuation observed after a mean 3.2 postoperative days. Mean hospitalization time was 4.7 days. Postoperative complications occurred in eight (27.5%) patients. Two (6.8%) stoma wound infections, right shoulder pain in two (6.8%) patients, one (3.4%) anastomotic dehiscence, one peritonitis probably due to contaminationfrom surgical instruments, a liquid pelvic coliection and an incisional haernia. 1n conclusion, videolaparoscopic restoration of the intestinal transit demonstrated to be safe and effective. It could be the method of choice because of its success in 90.6 per cent of the patients.

Regadas, Francisco Sérgio P.; Regadas, Sthela M. Murad; Rodrigues, Lusmar Veras

2000-02-01

264

Failure of d-psicose absorbed in the small intestine to metabolize into energy and its low large intestinal fermentability in humans.  

Science.gov (United States)

Experiments with rats have produced data on the metabolism and energy value of d-psicose; however, no such data have been obtained in humans. The authors assessed the availability of d-psicose absorbed in the small intestine by measuring carbohydrate energy expenditure (CEE) by indirect calorimetry. They measured the urinary excretion rate by quantifying d-psicose in urine for 48 hours. To examine d-psicose fermentation in the large intestine, the authors measured breath hydrogen gas and fermentability using 35 strains of intestinal bacteria. Six healthy subjects participated in the CEE test, and 14 participated in breath hydrogen gas and urine tests. d-Psicose fermentation subsequent to an 8-week adaptation period was also assessed by measuring hydrogen gas in 8 subjects. d-Psicose absorbed in the small intestine was not metabolized into energy, unlike glucose, because CEE did not increase within 3 hours of d-psicose ingestion (0.35 g/kg body weight [BW]). The accumulated d-psicose urinary excretion rates were around 70% for 0.34, 0.17, and 0.08 g/kg BW of ingested d-psicose. Low d-psicose fermentability was observed in intestinal bacteria and breath hydrogen gas tests, in which fructooligosaccharide (0.34, 0.17, and 0.08 g/kg BW) was used as a positive control because its available energy is known to be 8.4 kJ/g. Based on the results of the plot of breath hydrogen concentration vs calories ingested, the energy value of d-psicose was expected to be less than 1.6 kJ/g. Incremental d-psicose fermentability subsequent to an adaptation period was not observed. PMID:19765780

Iida, Tetsuo; Hayashi, Noriko; Yamada, Takako; Yoshikawa, Yuko; Miyazato, Shoko; Kishimoto, Yuka; Okuma, Kazuhiro; Tokuda, Masaaki; Izumori, Ken

2009-09-17

265

Failure of d-psicose absorbed in the small intestine to metabolize into energy and its low large intestinal fermentability in humans.  

UK PubMed Central (United Kingdom)

Experiments with rats have produced data on the metabolism and energy value of d-psicose; however, no such data have been obtained in humans. The authors assessed the availability of d-psicose absorbed in the small intestine by measuring carbohydrate energy expenditure (CEE) by indirect calorimetry. They measured the urinary excretion rate by quantifying d-psicose in urine for 48 hours. To examine d-psicose fermentation in the large intestine, the authors measured breath hydrogen gas and fermentability using 35 strains of intestinal bacteria. Six healthy subjects participated in the CEE test, and 14 participated in breath hydrogen gas and urine tests. d-Psicose fermentation subsequent to an 8-week adaptation period was also assessed by measuring hydrogen gas in 8 subjects. d-Psicose absorbed in the small intestine was not metabolized into energy, unlike glucose, because CEE did not increase within 3 hours of d-psicose ingestion (0.35 g/kg body weight [BW]). The accumulated d-psicose urinary excretion rates were around 70% for 0.34, 0.17, and 0.08 g/kg BW of ingested d-psicose. Low d-psicose fermentability was observed in intestinal bacteria and breath hydrogen gas tests, in which fructooligosaccharide (0.34, 0.17, and 0.08 g/kg BW) was used as a positive control because its available energy is known to be 8.4 kJ/g. Based on the results of the plot of breath hydrogen concentration vs calories ingested, the energy value of d-psicose was expected to be less than 1.6 kJ/g. Incremental d-psicose fermentability subsequent to an adaptation period was not observed.

Iida T; Hayashi N; Yamada T; Yoshikawa Y; Miyazato S; Kishimoto Y; Okuma K; Tokuda M; Izumori K

2010-02-01

266

The intestine plays a substantial role in human vitamin B6 metabolism: a Caco-2 cell model.  

UK PubMed Central (United Kingdom)

BACKGROUND: Vitamin B6 is present in various forms (vitamers) in the diet that need to be metabolized to pyridoxal phosphate (PLP), the active cofactor form of vitamin B6. In literature, the liver has been reported to be the major site for this conversion, whereas the exact role of the intestine remains to be elucidated. OBJECTIVE: To gain insight into the role of the intestine in human vitamin B6 metabolism. MATERIALS AND METHODS: Expression of the enzymes pyridoxal kinase (PK), pyridox(am)ine phosphate oxidase (PNPO) and PLP-phosphatase was determined in Caco-2 cells and in lysates of human intestine. Vitamin B6 uptake, conversion and excretion were studied in polarized Caco-2 cell monolayers. B6 vitamer concentrations (pyridoxine (PN), pyridoxal (PL), PLP, pyridoxamine (PM), pyridoxamine phosphate (PMP)) and pyridoxic acid (PA) were quantified by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) using stable isotope-labeled internal standards. RESULTS: The enzymatic system involved in vitamin B6 metabolism (PK, PNPO and PLP-phosphatase) is fully expressed in Caco-2 cells as well as in human intestine. We show uptake of PN, PM and PL by Caco-2 cells, conversion of PN and PM into PL and excretion of all three unphosphorylated B6 vitamers. CONCLUSION: We demonstrate, in a Caco-2 cell model, that the intestine plays a substantial role in human vitamin B6 metabolism.

Albersen M; Bosma M; Knoers NV; de Ruiter BH; Diekman EF; de Ruijter J; Visser WF; de Koning TJ; Verhoeven-Duif NM

2013-01-01

267

The Intestine Plays a Substantial Role in Human Vitamin B6 Metabolism: A Caco-2 Cell Model  

Science.gov (United States)

Background Vitamin B6 is present in various forms (vitamers) in the diet that need to be metabolized to pyridoxal phosphate (PLP), the active cofactor form of vitamin B6. In literature, the liver has been reported to be the major site for this conversion, whereas the exact role of the intestine remains to be elucidated. Objective To gain insight into the role of the intestine in human vitamin B6 metabolism. Materials and Methods Expression of the enzymes pyridoxal kinase (PK), pyridox(am)ine phosphate oxidase (PNPO) and PLP-phosphatase was determined in Caco-2 cells and in lysates of human intestine. Vitamin B6 uptake, conversion and excretion were studied in polarized Caco-2 cell monolayers. B6 vitamer concentrations (pyridoxine (PN), pyridoxal (PL), PLP, pyridoxamine (PM), pyridoxamine phosphate (PMP)) and pyridoxic acid (PA) were quantified by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) using stable isotope-labeled internal standards. Results The enzymatic system involved in vitamin B6 metabolism (PK, PNPO and PLP-phosphatase) is fully expressed in Caco-2 cells as well as in human intestine. We show uptake of PN, PM and PL by Caco-2 cells, conversion of PN and PM into PL and excretion of all three unphosphorylated B6 vitamers. Conclusion We demonstrate, in a Caco-2 cell model, that the intestine plays a substantial role in human vitamin B6 metabolism.

Albersen, Monique; Bosma, Marjolein; Knoers, Nine V. V. A. M.; de Ruiter, Berna H. B.; Diekman, Eugene F.; de Ruijter, Jessica; Visser, Wouter F.; de Koning, Tom J.; Verhoeven-Duif, Nanda M.

2013-01-01

268

Effects of oral casokefamide on plasma levels, tolerance, and intestinal transit in man.  

Science.gov (United States)

Food-derived opioid peptides such as beta-casomorphins are of interest for treatment of chronic diarrhea. The beta-casomorphin analog casokefamide was administered orally at doses of 5.5, 8.0, and 16.0 mg to 10 healthy male volunteers, respectively. Dose-dependent increases of plasma levels with a maximum of 350 fmol/l were determined. No side-effects due to casokefamide has been observed. In comparison to placebo, casokefamide showed a trend toward prolongation of oro-caecal transit time. Orally applied casokefamide is well tolerated and may represent a useful tool for treatment of diarrhea in the future. PMID:10793229

Schulte-Frohlinde, E; Reindl, W; Bierling, D; Lersch, C; Brantl, V; Teschemacher, H; Schusdziarra, V

2000-03-01

269

Perfil epidemiológico e morbimortalidade dos pacientes submetidos à reconstrução de trânsito intestinal: experiência de um centro secundário do nordeste Brasileiro Epidemiologic profile and morbimortality of patients undergoing to intestinal transit reconstruction: experience of a secundary health service in Brazil northeast  

Directory of Open Access Journals (Sweden)

Full Text Available Racional- A reconstrução do trânsito intestinal não está isenta de riscos cirúrgicos e apresenta taxas consideráveis de complicações pós-operatórias, sendo que a infecção continua a ser um dos maiores desafios existentes neste procedimento. Métodos- Foram analisados retrospectivamente 86 prontuários de pacientes com colostomia ou ileostomia, através de fatores que tivessem impacto sobre a morbimortalidade após a reconstrução de trânsito intestinal, de janeiro de 2003 a abril de 2009. Resultados- Houve 20 mulheres e 60 homens, com idade média de 43 anos. A colostomia em alça (n: 34) e o trauma abdominal indicando colostomia ou ileostomia foram as condições mais frequentes. O intervalo médio entre a confecção do estoma e a reconstrução de trânsito intestinal foi 15,7 meses. O índice de morbidade foi 56,8%, sendo a infecção incisional a complicação mais comum (27.47%). A permanência hospitalar média foi 7,6 dias. Houve regressão linear positiva entre permanência hospitalar pós-operatória e a idade do paciente. Demonstrou-se associação estatisticamente significativa entre o prolongamento da permanência hospitalar e a ocorrência de complicações (pBackground - The reconstruction of the intestinal tract is not surgical complications risk-free and is associated to postoperative complications high rates; furthermore, infection remains the hardest challenge in this procedure. Methods - Retrospectively, eighty-six patients with intestinal stomas were analyzed through factors that impact on the morbimortality afterwards intestinal transit reconstruction, since January 2003 to April 2009. Results - Loop colostomy (n=34) and abdominal trauma implicating 38.2% of indications to colostomy or ileostomy were the most frequent conditions. The mean interval between stoma confection and intestinal transit reconstruction was 15.7 months. The morbidity frequency was 56.8% and incisional infection was its commonest complication (27.47%). The mean inpatient length of stay was 7.6 days. There was positive linear regression between post-operative inpatient length of stay and inpatient's age. Inpatient length of stay prolongation is associated to occurrence of complications (p<0,001). Conclusion - Post-operative complications and age are associated to inpatient length of stay prolongation.

Jeany Borges e Silva; Djalma Ribeiro Costa; Francisco Julimar Correia de Menezes; José Marconi Tavares; Adryano Gonçalves Marques; Rodrigo Dornfeld Escalante

2010-01-01

270

Perfil epidemiológico e morbimortalidade dos pacientes submetidos à reconstrução de trânsito intestinal: experiência de um centro secundário do nordeste Brasileiro/ Epidemiologic profile and morbimortality of patients undergoing to intestinal transit reconstruction: experience of a secundary health service in Brazil northeast  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Racional- A reconstrução do trânsito intestinal não está isenta de riscos cirúrgicos e apresenta taxas consideráveis de complicações pós-operatórias, sendo que a infecção continua a ser um dos maiores desafios existentes neste procedimento. Métodos- Foram analisados retrospectivamente 86 prontuários de pacientes com colostomia ou ileostomia, através de fatores que tivessem impacto sobre a morbimortalidade após a reconstrução de trânsito intestinal, de (more) janeiro de 2003 a abril de 2009. Resultados- Houve 20 mulheres e 60 homens, com idade média de 43 anos. A colostomia em alça (n: 34) e o trauma abdominal indicando colostomia ou ileostomia foram as condições mais frequentes. O intervalo médio entre a confecção do estoma e a reconstrução de trânsito intestinal foi 15,7 meses. O índice de morbidade foi 56,8%, sendo a infecção incisional a complicação mais comum (27.47%). A permanência hospitalar média foi 7,6 dias. Houve regressão linear positiva entre permanência hospitalar pós-operatória e a idade do paciente. Demonstrou-se associação estatisticamente significativa entre o prolongamento da permanência hospitalar e a ocorrência de complicações (p Abstract in english Background - The reconstruction of the intestinal tract is not surgical complications risk-free and is associated to postoperative complications high rates; furthermore, infection remains the hardest challenge in this procedure. Methods - Retrospectively, eighty-six patients with intestinal stomas were analyzed through factors that impact on the morbimortality afterwards intestinal transit reconstruction, since January 2003 to April 2009. Results - Loop colostomy (n=34) a (more) nd abdominal trauma implicating 38.2% of indications to colostomy or ileostomy were the most frequent conditions. The mean interval between stoma confection and intestinal transit reconstruction was 15.7 months. The morbidity frequency was 56.8% and incisional infection was its commonest complication (27.47%). The mean inpatient length of stay was 7.6 days. There was positive linear regression between post-operative inpatient length of stay and inpatient's age. Inpatient length of stay prolongation is associated to occurrence of complications (p

Silva, Jeany Borges e; Costa, Djalma Ribeiro; Menezes, Francisco Julimar Correia de; Tavares, José Marconi; Marques, Adryano Gonçalves; Escalante, Rodrigo Dornfeld

2010-09-01

271

Randomized double-blind crossover study to determine the effects of erythromycin on small intestinal nutrient absorption and transit in the critically ill.  

UK PubMed Central (United Kingdom)

BACKGROUND: The gastrokinetic drug erythromycin is commonly administered to critically ill patients during intragastric feeding to augment small intestinal nutrient delivery. However, erythromycin has been reported to increase the prevalence of diarrhea, which may reflect reduced absorption and/or accelerated small intestinal transit. OBJECTIVE: The objective was to evaluate the effects of intravenous erythromycin on small intestinal nutrient absorption and transit in the critically ill. DESIGN: On consecutive days, erythromycin (200 mg in 20 mL 0.9% saline) or placebo (20 mL 0.9% saline) were infused intravenously between -20 and 0 min in a randomized, blinded, crossover fashion. Between 0 and 30 min, a liquid nutrient containing 3-O-methylglucose (3-OMG), [13C]triolein, and [(99m)Tc]sulfur colloid was administered directly into the small intestine at 2 kcal/min. Serum 3-OMG concentrations and exhaled (13)CO2 (indices of glucose and lipid absorption, respectively) were measured. Cecal arrival of the infused nutrient was determined by scintigraphy. Data are medians (ranges) and were analyzed by using Wilcoxon's signed-rank test. RESULTS: Thirty-two mechanically ventilated patients were studied. Erythromycin increased small intestinal glucose absorption [3-OMG AUC360: 105.2 (28.9-157.0) for erythromycin compared with 91.8 (51.4-147.9) mmol/L · min for placebo; P = 0.029] but tended to reduce lipid absorption [cumulative percentage dose (13)CO2 recovered: 10.4 (0-90.6) compared with 22.6 (0-100) %; P = 0.06]. A trend to slower transit was observed after erythromycin [300 (39-360) compared with 228 (33-360) min; P = 0.07]. CONCLUSIONS: Acute administration of erythromycin increases small intestinal glucose absorption in the critically ill, but there was a tendency for the drug to reduce small intestinal lipid absorption and slow transit. These observations have implications for the use of erythromycin as a gastrokinetic drug in the critically ill. This trial was registered in the Australian New Zealand Clinical Trials Registry as ACTRN 12610000615088.

Deane AM; Wong GL; Horowitz M; Zaknic AV; Summers MJ; Di Bartolomeo AE; Sim JA; Maddox AF; Bellon MS; Rayner CK; Chapman MJ; Fraser RJ

2012-06-01

272

TNF? regulates sugar transporters in the human intestinal epithelial cell line Caco-2.  

UK PubMed Central (United Kingdom)

PURPOSE: During intestinal inflammation TNF? levels are increased and as a consequence malabsorption of nutrients may occur. We have previously demonstrated that TNF? inhibits galactose, fructose and leucine intestinal absorption in animal models. In continuation with our work, the purpose of the present study was to investigate in the human intestinal epithelial cell line Caco-2, the effect of TNF? on sugar transport and to identify the intracellular mechanisms involved. METHODS: Caco-2 cells were grown on culture plates and pre-incubated during different periods with various TNF? concentrations before measuring the apical uptake of galactose, ?-methyl-glucoside (MG) or fructose for 15min. To elucidate the signaling pathway implicated, cells were pre-incubated for 30min with the PKA inhibitor H-89 or the PKC inhibitor chelerythrine, before measuring the sugar uptake. The expression in the apical membrane of the transporters implicated in the sugars uptake process (SGLT1 and GLUT5) was determined by Western blot. RESULTS: TNF? inhibited 0.1mM MG uptake after pre-incubation of the cells for 6-48h with the cytokine and in the absence of cytokine pre-incubation. In contrast, 5mM fructose uptake was stimulated by TNF? only after long pre-incubation times (24 and 48h). These effects were mediated by the binding of the cytokine to its specific receptor TNFR1, present in the apical membrane of the Caco-2 cells. Analysis of the expression of the MG and fructose transporters at the brush border membrane of the cells, after 24h pre-incubation with the cytokine, revealed decrease on the amount of SGLT1 and increase on the amount of GLUT5 proteins. Short-term inhibition of MG transport by TNF? was not modified by H-89 but was blocked by chelerythrine. CONCLUSIONS: SGLT1 and GLUT5 expression in the plasma membrane is regulated by TNF? in the human epithelial cell line Caco-2 cells, leading to alteration on sugars transport, suggesting that TNF? could be considered as a physiological local regulator of nutrients absorption in response to an intestinal inflammatory status.

Barrenetxe J; Sánchez O; Barber A; Gascón S; Rodríguez-Yoldi MJ; Lostao MP

2013-10-01

273

Evaluation by computerized morphometry of histopathological alterations of the colon wall in segments with and without intestinal transit in rats Avaliação por morfometria computadorizada das alterações histopatológicas da parede cólica em segmentos com e sem trânsito intestinal em ratos  

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Full Text Available PURPOSE: To evaluate histopathological alterations of the colon wall in segments with and without intestinal transit, by computer-assisted imaging, and to correlate these with the length of time diversion. METHODS: Thirty male Wistar rats were subjected to intestinal transit diversion by a proximal colostomy and distal mucosa fistula. The animals were divided into three experimental groups according to how long after the initial surgical procedure they were sacrificed: six, twelve and eighteen weeks. Colon segments with and without transit were subjected to histopathological study. The variables colon crypt length, mucosal ulceration, muscle layer thickness of the muscularis mucosa, submucosa and muscularis propria, vascular congestion, number of caliciform cells, inflammatory grade and degree of inflammation, comparing the two colon segments in the different experimental groups were studied. Intestinal crypt length, muscle layer thickness of the mucosa, submucosa and muscularis propria and caliciform cells were measured by computer-assisted imaging method. Mean equality, variance analysis and correlation tests were used in the statistical analysis, and the significance level was set at 5%. RESULTS: Comparison between segments with and without transit showed that the latter presented reduced length of colon crypts and increased muscle layer thickness of the muscularis mucosa, submucosa and muscularis propria. There were greater quantities of ulceration of the mucosal and greater degree of inflammation with increasing time without transit. Mucosal ulceration, submucosal vascular congestion, increased thickness of the submucosal and muscularis propria layers, presence of caliciform cells, inflammatory infiltrate and inflammatory grade correlated significantly with the length of time without transit. CONCLUSIONS: Histological alterations occurred in all layers of the colon wall, in the segments without intestinal transit. Ulcerations in the intestinal mucosa, increased number of caliciform cells, greater vascular congestion of the submucosal layer and inflammatory reaction were related to increasing length of time without transit.OBJETIVO: Avaliar por método de imagem assistida por computador as alterações histopatológicas da parede cólica em segmentos providos e desprovidos de trânsito intestinal e relacioná-las ao tempo de exclusão. MÉTODOS: Trinta ratos Wistar machos foram submetidos à derivação do trânsito no cólon esquerdo por meio de colostomia proximal e fístula mucosa distal. Os animais foram divididos em três grupos experimentais segundo o sacrifício ter sido realizado seis, doze e dezoito semanas após o procedimento cirúrgico inicial. Segmentos dos cólons providos e desprovidos de trânsito foram submetidos a estudo histopatológico. Foram analisadas as variáveis: comprimento das criptas cólicas, ulceração na mucosa, espessura das camadas muscular da mucosa, submucosa e muscular própria, congestão vascular, número de células caliciformes e graduação inflamatória comparando os dois segmentos cólicos nos diferentes grupos experimentais. As variáveis, comprimento das criptas intestinais, espessura das camadas muscular da mucosa, submucosa e muscular própria foram mensuradas por método de imagem assistida por computador. Na análise estatística foram utilizados testes de igualdade de médias e medianas, análise de variância e correlação estabelecendo-se nível de significância de cinco por cento. RESULTADOS: A exclusão de trânsito mostrou-se associada à redução do comprimento das criptas cólicas, aumento da espessura das camadas muscular da mucosa, submucosa e muscular própria. Verificou-se maior quantidade de ulcerações na mucosa e maior grau de inflamação com o progredir do tempo de exclusão. Houve correlação significante entre as ulcerações da mucosa, congestão vascular da submucosa, aumento da espessura das camadas submucosa e muscular própria, presença de células caliciformes, infiltrado inflamatório, graduação inflamatória e o t

Marcos Vieira de Sousa; Denise Gonçalves Priolli; Adriana Valim Portes; Izilda Aparecida Cardinalli; José Aires Pereira; Carlos Augusto Real Martinez

2008-01-01

274

Dysfunctions at human intestinal barrier by water-borne protozoan parasites: lessons from cultured human fully differentiated colon cancer cell lines.  

UK PubMed Central (United Kingdom)

Some water-borne protozoan parasites induce diseases through their membrane-associated functional structures and virulence factors that hijack the host cellular molecules and signalling pathways leading to structural and functional lesions in the intestinal barrier. In this Microreview we analyse the insights on the mechanisms of pathogenesis of Entamoeba intestinalis, Giardia and Cryptosporidium observed in the human colon carcinoma fully differentiated colon cancer cell lines, cell subpopulations and clones expressing the structural and functional characteristics of highly specialized fully differentiated epithelial cells lining the intestinal epithelium and mimicking structurally and functionally an intestinal barrier.

Liévin-Le Moal V

2013-06-01

275

Dysfunctions at human intestinal barrier by water-borne protozoan parasites: lessons from cultured human fully differentiated colon cancer cell lines.  

Science.gov (United States)

Some water-borne protozoan parasites induce diseases through their membrane-associated functional structures and virulence factors that hijack the host cellular molecules and signalling pathways leading to structural and functional lesions in the intestinal barrier. In this Microreview we analyse the insights on the mechanisms of pathogenesis of Entamoeba intestinalis, Giardia and Cryptosporidium observed in the human colon carcinoma fully differentiated colon cancer cell lines, cell subpopulations and clones expressing the structural and functional characteristics of highly specialized fully differentiated epithelial cells lining the intestinal epithelium and mimicking structurally and functionally an intestinal barrier. PMID:23437821

Liévin-Le Moal, Vanessa

2013-03-14

276

Mapping of liver-enriched transcription factors in the human intestine.  

UK PubMed Central (United Kingdom)

AIM: To investigate the gene expression pattern of hepatocyte nuclear factor 6 (HNF6) and other liver-enriched transcription factors in various segments of the human intestine to better understand the differentiation of the gut epithelium. METHODS: Samples of healthy duodenum and jejunum were obtained from patients with pancreatic cancer whereas ileum and colon was obtained from patients undergoing right or left hemicolectomy or (recto)sigmoid or rectal resection. All surgical specimens were subjected to histopathology. Excised tissue was shock-frozen and analyzed for gene expression of liver-enriched transcription factors by semiquantitative reverse transcription polymerase chain and compared to the human colon carcinoma cell line Caco-2. Protein expression of major liver-enriched transcription factors was determined by Western blotting while the DNA binding of HNF6 was investigated by electromobility shift assays. RESULTS: The gene expression patterning of liver-enriched transcription factors differed in the various segments of the human intestine with HNF6 gene expression being most abundant in the duodenum (P < 0.05) whereas expression of the zinc finger protein GATA4 and of the HNF6 target gene ALDH3A1 was most abundant in the jejunum (P < 0.05). Likewise, expression of FOXA2 and the splice variants 2 and 4 of HNF4alpha were most abundantly expressed in the jejunum (P < 0.05). Essentially, expression of transcription factors declined from the duodenum towards the colon with the most abundant expression in the jejunum and less in the ileum. The expression of HNF6 and of genes targeted by this factor, i.e. neurogenin 3 (NGN3) was most abundant in the jejunum followed by the ileum and the colon while DNA binding activity of HNF4alpha and of NGN3 was confirmed by electromobility shift assays to an optimized probe. Furthermore, Western blotting provided evidence of the expression of several liver-enriched transcription factors in cultures of colon epithelial cells, albeit at different levels. CONCLUSION: We describe significant local and segmental differences in the expression of liver-enriched transcription factors in the human intestine which impact epithelial cell biology of the gut.

Lehner F; Kulik U; Klempnauer J; Borlak J

2010-08-01

277

Mapping of liver-enriched transcription factors in the human intestine  

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Full Text Available AIM: To investigate the gene expression pattern of hepatocyte nuclear factor 6 (HNF6) and other liver-enriched transcription factors in various segments of the human intestine to better understand the differentiation of the gut epithelium.METHODS: Samples of healthy duodenum and jejunum were obtained from patients with pancreatic cancer whereas ileum and colon was obtained from patients undergoing right or left hemicolectomy or (recto)sigmoid or rectal resection. All surgical specimens were subjected to histopathology. Excised tissue was shock-frozen and analyzed for gene expression of liver-enriched transcription factors by semiquantitative reverse transcription polymerase chain and compared to the human colon carcinoma cell line Caco-2. Protein expression of major liver-enriched transcription factors was determined by Western blotting while the DNA binding of HNF6 was investigated by electromobility shift assays.RESULTS: The gene expression patterning of liver-enriched transcription factors differed in the various segments of the human intestine with HNF6 gene expression being most abundant in the duodenum (P < 0.05) whereas expression of the zinc finger protein GATA4 and of the HNF6 target gene ALDH3A1 was most abundant in the jejunum (P < 0.05). Likewise, expression of FOXA2 and the splice variants 2 and 4 of HNF4? were most abundantly expressed in the jejunum (P < 0.05). Essentially, expression of transcription factors declined from the duodenum towards the colon with the most abundant expression in the jejunum and less in the ileum. The expression of HNF6 and of genes targeted by this factor, i.e. neurogenin 3 (NGN3) was most abundant in the jejunum followed by the ileum and the colon while DNA binding activity of HNF4? and of NGN3 was confirmed by electromobility shift assays to an optimized probe. Furthermore, Western blotting provided evidence of the expression of several liver-enriched transcription factors in cultures of colon epithelial cells, albeit at different levels.CONCLUSION: We describe significant local and segmental differences in the expression of liver-enriched transcription factors in the human intestine which impact epithelial cell biology of the gut.

Frank Lehner, Ulf Kulik, Juergen Klempnauer,Juergen Borlak

2010-01-01

278

Diet shapes the ability of human intestinal microbiota to degrade phytate--in vitro studies.  

UK PubMed Central (United Kingdom)

AIMS: Investigation of intestinal bacterial groups involved in phytate degradation and the impact of diets with different phytate contents on phytase activity. METHODS AND RESULTS: Faecal samples of adults on conventional (n = 8) or vegetarian (n = 8) diets and breastfed infants (n = 6) were used as an inoculum for modified media supplemented with phytate. Populations of Gram-positive anaerobes (GPA), lactic acid bacteria (LAB), Proteobacteria-Bacteroides (P-B), coliforms and anaerobes were studied. The PCR-DGGE analysis revealed a random distribution of DGGE profiles in the dendrograms of GPA, P-B and coliforms, and a partially diet-specific distribution in the DGGE dendrograms of LAB and anaerobes. The degradation of phytic acid (PA) was determined with HPLC method in supernatants of the cultures. Regardless of the diet, the Gram-positive anaerobes and LAB displayed the lowest ability to degrade phytate, whereas the coliforms and P-B cultures produced higher amounts of intermediate myo-inositol phosphates. Bacterial populations grown in a nonselective medium were the most effective ones in phytate degradation. It was the vegetarians' microbiota that particularly degraded up to 100% phytate to myo-inositol phosphate products lower than InsP3. CONCLUSIONS: A diet rich in phytate increases the potential of intestinal microbiota to degrade phytate. The co-operation of aerobic and anaerobic bacteria is essential for the complete phytate degradation. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides insights on the effect of diet on specific metabolic activity of human intestinal microbiota.

Markiewicz LH; Honke J; Haros M; ?wi?tecka D; Wróblewska B

2013-07-01

279

Quantitative evaluation of neurons in the mucosal plexus of adult human intestines.  

Science.gov (United States)

The consequence of presence versus absence of mucosal neurons is not consistently assessed. Here, we addressed two questions. First, based on resected gut specimens of 65 patients/body donors suffering from different diseases, counts of mucosal neurons per mm(2) were analysed with respect to age, gender and region. Second, we evaluated resected megacolonic specimens of four patients suffering from chronic Chagas' disease. Mucosal wholemounts were triple-stained for calretinin (CALR), peripherin (PER) and human neuronal protein Hu C/D (HU). Counts revealed no clear correlation between the presence of mucosal neurons and age, gender or region. Mucosal neurons were present in 30 of 36 specimens derived from males (83%) and in 20 of 29 from females (69%). The numbers per mm(2) increased from duodenum to ileum (1.7-10.8) and from ascending to sigmoid colon (3.2-9.9). Out of 149 small intestinal mucosal neurons, 47% were co-reactive for CALR, PER and HU (large intestine: 76% of 300 neurons) and 48% for PER and HU only (large intestine: 23%). In 12 megacolonic specimens (each 3 from 4 patients), all 23 mucosal neurons found (1.9 per mm(2)) displayed co-reactivity for CALR, PER and HU. We suggest that the presence or the absence of mucosal neurons is variable, ongoing studies will address our assumption that they correspond in their morphochemical characteristics to submucosal neurons. Furthermore, both the architecture and neuron number of the megacolonic mucosal plexus displayed no dramatic changes indicating that mucosal nerves might be less involved in chagasic/megacolonic neurodegeneration as known from the myenteric plexus. PMID:21461752

Kramer, Kerstin; da Silveira, Alexandre B M; Jabari, Samir; Kressel, Michael; Raab, Marion; Brehmer, Axel

2011-04-02

280

Quantitative evaluation of neurons in the mucosal plexus of adult human intestines.  

UK PubMed Central (United Kingdom)

The consequence of presence versus absence of mucosal neurons is not consistently assessed. Here, we addressed two questions. First, based on resected gut specimens of 65 patients/body donors suffering from different diseases, counts of mucosal neurons per mm(2) were analysed with respect to age, gender and region. Second, we evaluated resected megacolonic specimens of four patients suffering from chronic Chagas' disease. Mucosal wholemounts were triple-stained for calretinin (CALR), peripherin (PER) and human neuronal protein Hu C/D (HU). Counts revealed no clear correlation between the presence of mucosal neurons and age, gender or region. Mucosal neurons were present in 30 of 36 specimens derived from males (83%) and in 20 of 29 from females (69%). The numbers per mm(2) increased from duodenum to ileum (1.7-10.8) and from ascending to sigmoid colon (3.2-9.9). Out of 149 small intestinal mucosal neurons, 47% were co-reactive for CALR, PER and HU (large intestine: 76% of 300 neurons) and 48% for PER and HU only (large intestine: 23%). In 12 megacolonic specimens (each 3 from 4 patients), all 23 mucosal neurons found (1.9 per mm(2)) displayed co-reactivity for CALR, PER and HU. We suggest that the presence or the absence of mucosal neurons is variable, ongoing studies will address our assumption that they correspond in their morphochemical characteristics to submucosal neurons. Furthermore, both the architecture and neuron number of the megacolonic mucosal plexus displayed no dramatic changes indicating that mucosal nerves might be less involved in chagasic/megacolonic neurodegeneration as known from the myenteric plexus.

Kramer K; da Silveira AB; Jabari S; Kressel M; Raab M; Brehmer A

2011-07-01

 
 
 
 
281

Mechanism of riboflavine uptake by Caco-2 human intestinal epithelial cells.  

Science.gov (United States)

The cellular and molecular regulation of intestinal absorption of the water-soluble vitamin riboflavine (RF) is poorly understood. The availability of a suitable in vitro cultured system that possesses the transport characteristics of the native intestinal absorptive cells would provide a powerful means to address this issue. In this study, we examined RF uptake by the human-derived cultured Caco-2 intestinal epithelial cells. RF uptake was Na+ and pH independent and occurred without metabolic alterations of the transported RF. Initial rate of RF uptake was temperature dependent and saturable as a function of concentration at 37 degrees C but not at 4 degrees C (apparent Michaelis constant = 0.30 +/- 0.03 microM, maximal velocity = 209.90 +/- 24.40 pmol.mg protein-1.3 min-1). Unlabeled RF, lumiflavine, 8-amino-riboflavine, isoriboflavine, and lumichrome in the incubation solution caused significant inhibition of RF uptake. RF uptake was also energy dependent and was sensitive to the inhibitory effect of sulfhydryl group reagents. The membrane transport inhibitor amiloride, but not 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, 4-acetamide-4'-isothiocyanostilbene-2,2'-disulfonic acid, furosemide, or probenecid, inhibited RF uptake in a competitive (inhibitory constant = 0.48 mM) and reversible manner. Growing Caco-2 monolayers in a RF-deficient and oversupplemented media caused significant up- and downregulation of RF uptake, respectively. These results demonstrate the existence of a carrier-mediated system for RF uptake by Caco-2 cells and provide new information regarding amiloride sensitivity, involvement of sulfhydryl groups, and up- and downregulation by the substrate level and clarify the controversy regarding the role of Na+ in the uptake process.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8304455

Said, H M; Ma, T Y

1994-01-01

282

Mechanism of riboflavine uptake by Caco-2 human intestinal epithelial cells.  

UK PubMed Central (United Kingdom)

The cellular and molecular regulation of intestinal absorption of the water-soluble vitamin riboflavine (RF) is poorly understood. The availability of a suitable in vitro cultured system that possesses the transport characteristics of the native intestinal absorptive cells would provide a powerful means to address this issue. In this study, we examined RF uptake by the human-derived cultured Caco-2 intestinal epithelial cells. RF uptake was Na+ and pH independent and occurred without metabolic alterations of the transported RF. Initial rate of RF uptake was temperature dependent and saturable as a function of concentration at 37 degrees C but not at 4 degrees C (apparent Michaelis constant = 0.30 +/- 0.03 microM, maximal velocity = 209.90 +/- 24.40 pmol.mg protein-1.3 min-1). Unlabeled RF, lumiflavine, 8-amino-riboflavine, isoriboflavine, and lumichrome in the incubation solution caused significant inhibition of RF uptake. RF uptake was also energy dependent and was sensitive to the inhibitory effect of sulfhydryl group reagents. The membrane transport inhibitor amiloride, but not 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, 4-acetamide-4'-isothiocyanostilbene-2,2'-disulfonic acid, furosemide, or probenecid, inhibited RF uptake in a competitive (inhibitory constant = 0.48 mM) and reversible manner. Growing Caco-2 monolayers in a RF-deficient and oversupplemented media caused significant up- and downregulation of RF uptake, respectively. These results demonstrate the existence of a carrier-mediated system for RF uptake by Caco-2 cells and provide new information regarding amiloride sensitivity, involvement of sulfhydryl groups, and up- and downregulation by the substrate level and clarify the controversy regarding the role of Na+ in the uptake process.(ABSTRACT TRUNCATED AT 250 WORDS)

Said HM; Ma TY

1994-01-01

283

Intestinal microbiology in early life: specific prebiotics can have similar functionalities as human-milk oligosaccharides.  

Science.gov (United States)

Human milk is generally accepted as the best nutrition for newborns and has been shown to support the optimal growth and development of infants. On the basis of scientific insights from human-milk research, a specific mixture of nondigestible oligosaccharides has been developed, with the aim to improve the intestinal microbiota in early life. The mixture has been extensively studied and has been shown to be safe and to have potential health benefits that are similar to those of human milk. The specific mixture of short-chain galacto-oligosaccharides and long-chain fructo-oligosaccharides has been found to affect the development of early microbiota and to increase the Bifidobacterium amounts as observed in human-milk-fed infants. The resulting gut ecophysiology is characterized by high concentrations of lactate, a slightly acidic pH, and specific short-chain fatty acid profiles, which are high in acetate and low in butyrate and propionate. Here, we have summarized the main findings of dietary interventions with these specific oligosaccharides on the gut microbiota in early life. The gut ecophysiology in early life may have consequences for the metabolic, immunologic, and even neurologic development of the child because reports increasingly substantiate the important function of gut microbes in human health. This review highlights major findings in the field of early gut colonization and the potential impact of early nutrition in healthy growth and development. PMID:23824728

Oozeer, Raish; van Limpt, Kees; Ludwig, Thomas; Ben Amor, Kaouther; Martin, Rocio; Wind, Richèle D; Boehm, Günther; Knol, Jan

2013-07-03

284

Intestinal microbiology in early life: specific prebiotics can have similar functionalities as human-milk oligosaccharides.  

UK PubMed Central (United Kingdom)

Human milk is generally accepted as the best nutrition for newborns and has been shown to support the optimal growth and development of infants. On the basis of scientific insights from human-milk research, a specific mixture of nondigestible oligosaccharides has been developed, with the aim to improve the intestinal microbiota in early life. The mixture has been extensively studied and has been shown to be safe and to have potential health benefits that are similar to those of human milk. The specific mixture of short-chain galacto-oligosaccharides and long-chain fructo-oligosaccharides has been found to affect the development of early microbiota and to increase the Bifidobacterium amounts as observed in human-milk-fed infants. The resulting gut ecophysiology is characterized by high concentrations of lactate, a slightly acidic pH, and specific short-chain fatty acid profiles, which are high in acetate and low in butyrate and propionate. Here, we have summarized the main findings of dietary interventions with these specific oligosaccharides on the gut microbiota in early life. The gut ecophysiology in early life may have consequences for the metabolic, immunologic, and even neurologic development of the child because reports increasingly substantiate the important function of gut microbes in human health. This review highlights major findings in the field of early gut colonization and the potential impact of early nutrition in healthy growth and development.

Oozeer R; van Limpt K; Ludwig T; Ben Amor K; Martin R; Wind RD; Boehm G; Knol J

2013-08-01

285

Somatostatin, substance P and calcitonin gene-related peptide-positive intramural nerve structures of the human large intestine affected by carcinoma.  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this study was to investigate the arrangement and chemical coding of enteric nerve structures in the human large intestine affected by cancer. Tissue samples comprising all layers of the intestinal wall were collected during surgery form both morphologically unchanged and pathologically altered segments of the intestine (n=15), and fixed by immersion in buffered paraformaldehyde solution. The cryostat sections were processed for double-labelling immunofluorescence to study the distribution of the intramural nerve structures (visualized with antibodies against protein gene-product 9.5) and their chemical coding using antibodies against somatostatin (SOM), substance P (SP) and calcitonin gene-related peptide (CGRP). The microscopic observations revealed distinct morphological differences in the enteric nerve system structure between the region adjacent to the cancer invaded area and the intact part of the intestine. In general, infiltration of the cancer tissue resulted in the gradual (depending on the grade of invasion) first decomposition and reduction to final partial or complete destruction and absence of the neuronal elements. A comparative analysis of immunohistochemically labeled sections (from the unchanged and pathologically altered areas) revealed a statistically significant decrease in the number of CGRP-positive neurons and nerve fibres in both submucous and myenteric plexuses in the transitional zone between morphologically unchanged and cancer-invaded areas. In this zone, a decrease was also observed in the density of SP-positive nerve fibres in all intramural plexuses. Conversely, the investigations demonstrated statistically insignificant differences in number of SP- and SOM-positive neurons and a similar density of SOM-positive nerve fibres in the plexuses of the intact and pathologically changed areas. The differentiation between the potential adaptive changes in ENS or destruction of its elements by cancer invasion should be a subject of further investigations.

Janusz Godlewski; Jerzy Kaleczyc

2010-01-01

286

ERK-associated changes in E2F4 phosphorylation, localization and transcriptional activity during mitogenic stimulation in human intestinal epithelial crypt cells.  

UK PubMed Central (United Kingdom)

BACKGROUND: The transcription factor E2F4 controls proliferation of normal and cancerous intestinal epithelial cells. E2F4 localization in normal human intestinal epithelial cells (HIEC) is cell cycle-dependent, being cytoplasmic in quiescent differentiated cells but nuclear in proliferative cells. However, the intracellular signaling mechanisms regulating such E2F4 localization remain unknown. RESULTS: Treatment of quiescent HIEC with serum induced ERK1/2 activation, E2F4 phosphorylation, E2F4 nuclear translocation and G1/S phase transition while inhibition of MEK/ERK signaling by U0126 prevented these events. Stimulation of HIEC with epidermal growth factor (EGF) also led to the activation of ERK1/2 but, in contrast to serum or lysophosphatidic acid (LPA), EGF failed to induce E2F4 phosphorylation, E2F4 nuclear translocation and G1/S phase transition. Furthermore, Akt and GSK3? phosphorylation levels were markedly enhanced in serum- or LPA-stimulated HIEC but not by EGF. Importantly, E2F4 phosphorylation, E2F4 nuclear translocation and G1/S phase transition were all observed in response to EGF when GSK3 activity was concomitantly inhibited by SB216763. Finally, E2F4 was found to be overexpressed, phosphorylated and nuclear localized in epithelial cells from human colorectal adenomas exhibiting mutations in APC and KRAS or BRAF genes, known to deregulate GSK3/?-catenin and MEK/ERK signaling, respectively. CONCLUSIONS: The present results indicate that MEK/ERK activation and GSK3 inhibition are both required for E2F4 phosphorylation as well as its nuclear translocation and S phase entry in HIEC. This finding suggests that dysregulated E2F4 nuclear localization may be an instigating event leading to hyperproliferation and hence, of tumor initiation and promotion in the colon and rectum.

Paquin MC; Cagnol S; Carrier JC; Leblanc C; Rivard N

2013-01-01

287

Vitamin A metabolism in the human intestinal Caco-2 cell line  

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The human intestinal Caco-2 cell line, described as enterocyte-like in a number of studies, was examined for its ability to carry out the metabolism of vitamin A normally required in the absorptive process. Caco-2 cells contained cellular retinol-binding protein II, a protein which is abundant in human villus-associated enterocytes and may play an important role in the absorption of vitamin A. Microsomal preparations from Caco-2 cells contained retinal reductase, acyl-CoA-retinol acyltransferase (ARAT), and lecithin-retinol acyltransferase (LRAT) activites, which have previously been proposed to be involved in the metabolism of dietary vitamin A in the enterocyte. When intact Caco-2 cells were provided with {beta}-carotene, retinyl acetate, or retinyl acetate, or retinol, synthesis of retinyl palmitoleate, oleate, palmitate, and small amounts of stearate resulted. However, exogenous retinyl palmitate or stearate was not used by Caco-2 cells as a source of retinol for ester synthesis. While there was a disproportionate synthesis of monoenoic fatty acid esters of retinol in Caco-2 cells compared to the retinyl esters typically found in human chylomicrons or the esters normally synthesized in rat intestine, the pattern was consistent with the substantial amount of unsaturated fatty acids, particularly 18:1 and 16:1, found in the sn-1 position of Caco-2 microsomal phosphatidylcholine, the fatty acyl donor for LRAT. Both ARAT and LRAT have been proposed to be responsible for retinyl ester synthesis in the enterocyte. These data suggest the LRAT may be the physiologically important enzyme for the esterification of retinol in Caco-2 cells.

Quick, T.C.; Ong, D.E. (Vanderbilt Univ. School of Medicine, Nashville, TN (USA))

1990-12-01

288

hTERT and TP53 deregulation in intestinal-type gastric carcinogenesis in non-human primates.  

UK PubMed Central (United Kingdom)

Despite the high incidence, the molecular events involved in intestinal-type gastric carcinogenesis remains unclear. We previously established an intestinal-type gastric carcinogenesis model in Cebus apella, a New World monkey. In the present study, we evaluated hTERT and TP53 mRNA expression, as well as their protein immunoreactivity, in normal mucosa, non-atrophic gastritis, atrophic gastritis, intestinal metaplasia, and intestinal-type gastric cancer samples of non-human primates treated with N-methyl-nitrosourea. In addition, we evaluated the number of TP53 copies in these samples. Although hTERT immunoreactivity was only detected in gastric cancer, a continuous increase of hTERT mRNA expression was observed from non-atrophic gastritis to gastric tumors. No sample presented p53 immunoreactivity. However, we also observed a continuous decrease of TP53 mRNA expression during the sequential steps of gastric carcinogenesis. Moreover, loss of TP53 copies was observed in intestinal metaplasia and gastric cancer samples. Our study highlights that hTERT and TP53 have a key role in intestinal-type gastric cancer initiation.

Leal MF; Calcagno DQ; Khayat AS; Silva TC; Muniz JA; Assumpção PP; de Arruda Cardoso Smith M; Burbano RR

2013-08-01

289

Sympathetic nervous control of intramural blood flow in the feline and human intestines.  

UK PubMed Central (United Kingdom)

Intramural blood flow and flow distribution in the feline and human intestines were investigated by means of a recently developed inert gas elimination technique during electrical stimulation of the regional sympathetic nerve fibers. The results obtained in man and cat showed qualitative and quantitative similarities. Thus, observations made on man strongly suggested that the intestine exhibited an autoregulatory escape from the vasoconstrictor fiber influence in the same manner as was seen in the cat. During the steady state phase of vasoconstriction induced by nervous stimulation at 8 Hz, blood flow in the mucosa-submucosa and in the muscularis was decreased to the same extent as was total blood flow in the cat, implying that flow distribution to these two major portions of the bowel remained unaltered. In man, the vasoconstriction was somewhat more pronounced in the muscularis than in the mucosa-submucosa. Hence, in man a comparatively larger fraction of total blood flow was diverted to the mucosa-submucosa during nervous vasoconstriction.

Hultén L; Lindhagen J; Lundgren O

1977-01-01

290

Inhibition of Toxoplasma gondii replication in IFN-gamma-activated human intestinal epithelial cells.  

UK PubMed Central (United Kingdom)

Toxoplasma gondii is an obligate intracellular parasite which is responsible for severe disease after congenital infection and in immunocompromised patients, for which there is no effective therapy. In acquired toxoplasmosis, T. gondii first invade enterocytes and are disseminated throughout the body. Treatment of the adherent human intestinal cell line CaCO2 with recombinant human IFN-gamma inhibited the replication of T. gondii. Growth of the parasite was measured in vitro by [3H]-uracil incorporation assays 18 h after infection. This assay showed that when cells were pretreated with IFN-gamma concentrations ranging from 2.5 to 5000 U/ml, a high degree of inhibition of T. gondii replication could be observed, with the effect being dose dependent. This could be of relevance as a first line of defence against human Toxoplasma infection. Inhibition is due to a different mechanism from that existing in mouse macrophages and human fibroblasts: L-arginine-dependent production of reactive nitrogen intermediates, reactive oxygen intermediates synthesis or production of indoleamine 2.3 dioxygenase were not responsible for inhibition of T. gondii proliferation.

Dimier IH; Bout DT

1997-10-01

291

Inhibition of Toxoplasma gondii replication in IFN-gamma-activated human intestinal epithelial cells.  

Science.gov (United States)

Toxoplasma gondii is an obligate intracellular parasite which is responsible for severe disease after congenital infection and in immunocompromised patients, for which there is no effective therapy. In acquired toxoplasmosis, T. gondii first invade enterocytes and are disseminated throughout the body. Treatment of the adherent human intestinal cell line CaCO2 with recombinant human IFN-gamma inhibited the replication of T. gondii. Growth of the parasite was measured in vitro by [3H]-uracil incorporation assays 18 h after infection. This assay showed that when cells were pretreated with IFN-gamma concentrations ranging from 2.5 to 5000 U/ml, a high degree of inhibition of T. gondii replication could be observed, with the effect being dose dependent. This could be of relevance as a first line of defence against human Toxoplasma infection. Inhibition is due to a different mechanism from that existing in mouse macrophages and human fibroblasts: L-arginine-dependent production of reactive nitrogen intermediates, reactive oxygen intermediates synthesis or production of indoleamine 2.3 dioxygenase were not responsible for inhibition of T. gondii proliferation. PMID:9429902

Dimier, I H; Bout, D T

1997-10-01

292

Tspan-1 interacts with the thiamine transporter-1 in human intestinal epithelial cells and modulates its stability  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The human thiamine transporter-1 (hTHTR-1) contributes to intestinal thiamine uptake, and its function is regulated at both the transcriptional and posttranscriptional levels. Nothing, however, is known about the protein(s) that may interact with hTHTR-1 and affects its cell biology and physiology. ...

Nabokina, Svetlana M.; Senthilkumar, Sundar Rajan; Said, Hamid M.

293

Primary culture of human keratinocytes planted on pig’s intestine  

Directory of Open Access Journals (Sweden)

Full Text Available Tissue engineering, in the fields of skin regeneration,seeks to overcome the limitationsassociated with the use of immediate auto-grafts,since choosing the donor region of the patientconstitutes a risk for the patient himself and isinsufficient if the injury that has to be repairedis very large. The use of the pig’s small intestinesubmucosa (SIS) has being proved as a fillingbiomaterial to treat injuries, because of its specialcomposition, it lowers pain and inflammationsince its first application and it favours earlymobility to the wounded area. The present studydeveloped a protocol for the primary cultureof human keratinocytes from infant foreskins,and used small intestinal submucosa (SIS) likeculture substrate. Cellular adherence potentialand proliferation capability of the keratinocytesover this substrate was evaluated.

Ángela Ximena Amórtegui; Sandra Rocío Ramírez

2008-01-01

294

Butyrate stimulates IL-32? expression in human intestinal epithelial cell lines  

Science.gov (United States)

AIM: To investigate the effects of butyrate on interleukin (IL)-32? expression in epithelial cell lines. METHODS: The human intestinal epithelial cell lines HT-29, SW480, and T84 were used. Intracellular IL-32? was determined by Western blotting analyses. IL-32? mRNA expression was analyzed by real-time polymerase chain reaction. RESULTS: Acetate and propionate had no effects on IL-32? mRNA expression. Butyrate significantly enhanced IL-32? expression in all cell lines. Butyrate also up-regulated IL-1?-induced IL-32? mRNA expression. Butyrate did not modulate the activation of phosphatidylinositol 3-kinase (PI3K), a mediator of IL-32? expression. Like butyrate, trichostatin A, a histone deacetylase inhibitor, also enhanced IL-1?-induced IL-32? mRNA expression. CONCLUSION: Butyrate stimulated IL-32? expression in epithelial cell lines. An epigenetic mechanism, such as histone hyperacetylation, might be involved in the action of butyrate on IL-32? expression.

Kobori, Ayako; Bamba, Shigeki; Imaeda, Hirotsugu; Ban, Hiromitsu; Tsujikawa, Tomoyuki; Saito, Yasuharu; Fujiyama, Yoshihide; Andoh, Akira

2010-01-01

295

Specific binding of lactoferrin to Escherichia coli isolated from human intestinal infections  

International Nuclear Information System (INIS)

The degrees of human lactoferrin (HLf) and bovine lactoferrin (BLf) binding in 169 Escherichia coli strains isolated from human intestinal infections, and in an additional 68 strains isolated from healthy individuals, were examined in a 125I-labelled protein binding assay. The binding was expressed as a percentage calculated from the total labelled ligand added to bacteria. The HLf and BLf binding to E. coli was in the range 3.7 to 73.4% and 4.8 to 61.6%, respectively. Enterotoxigenic strains demonstrated a significantly higher HLf binding (median = 19%) than enteropathogenic, enteroinvasive, enterohaemorrhagic strains or normal intestinal E. coli isolates (medians 6 to 9). Enteropathogenic strains belonging to serotypes O44 and O127 demonstrated significantly higher HLf binding compared to O26, O55, O111, O119 and O126. No significant differences in the degree of HLf or BLf binding were found between aerobactin-producing and non-producing strains. The interaction was further characterized in a high Lf-binging EPEC strain, E34663 (serotype O127). The binding was stable in the pH range 4.0 to 7.5, did not dissociate in the presence of 2M NaCl or 2M urea, and reached saturation within two h. Unlabelled HLf and BLf displaced the 125I-HLf binding to E34663 in a dose-dependent manner. Apo- and iron-saturated forms of Lf demonstrated similar binding to E34663. Among various unlabelled subephithelial matrix proteins and carbohydrates tested (in 104-fold excess) only fibronectin and fibrinogen caused a moderate inhibition of 125I-HLf binding. According to Scatchard plot analysis, 5,400 HLf-binding sites/cell, with an affinity constant (Ka) of 1.4 x 10-7 M, were estimated in strain E34663. These data establish the presence of a specific Lf-binding mechanism in E. coli. (au).

1991-01-01

296

Role of ascorbic acid in procollagen expression and secretion by human intestinal smooth muscle cells.  

Science.gov (United States)

The role of ascorbate in the production and secretion of procollagen by human intestinal smooth muscle cells and the conditions in culture for optimal ascorbate bioefficacy were studied. Procollagen synthesis and secretion were determined by the incubation of cells with L-[5-3H]proline, and the quantitation of radiolabelled procollagen bands in the cell layer and the culture medium by polyacrylamide slab gel electrophoresis and densitometry. When cells were cultured without ascorbate in the culture medium, procollagen secretion into the medium was 75% less than in cells receiving fresh ascorbate daily. In the cell layer, in contrast, procollagen accumulation was fourfold greater in the scorbutic cells than in the ascorbate-replete cells. These findings contrasted with those in a control line of scorbutic human dermal fibroblasts in which a 95% decrease in procollagen secretion was not associated with any procollagen accumulation in the cells. In the intestinal smooth muscle cells, the absence of ascorbate resulted in a 25 and 50% decrease in steady-state levels of procollagen I and III mRNA, respectively, compared to a 40 and 75% decrease in fibroblasts. Heat inactivation of the serum in the culture medium augmented the promotion of procollagen secretion by ascorbate two- to fourfold. L-ascorbate phosphate did not increase the activity of L-ascorbate when replaced in medium either daily or every 4 days, and its efficacy was not augmented by serum heat inactivation. The changing of culture medium induced collagen secretion in the absence of ascorbate, but this process was markedly enhanced by ascorbate and induced a transient decrease in the steady-state levels of both procollagen and nonprocollagen mRNAs. The predominant action of L-ascorbate on HISM cells in vitro is to promote procollagen secretion and not procollagen synthesis. L-ascorbate-phosphate is not an adequate substitute for L-ascorbate in this cell line. PMID:7822432

Graham, M F; Willey, A; Adams, J; Yager, D; Diegelmann, R F

1995-02-01

297

Role of hydrogen peroxide in ACh-induced dilation of human submucosal intestinal microvessels.  

Science.gov (United States)

The endothelium plays an important role in maintaining vascular homeostasis by synthesizing and releasing several mediators of vasodilation, which include prostacyclin (PGI(2)), nitric oxide, and endothelium-derived hyperpolarizing factor (EDHF). We have recently defined the role of nitric oxide and PGI(2) in the dilation of submucosal intestinal arterioles from patients with normal bowel function. However, significant endothelium-dependent dilator capacity to ACh remained after inhibiting both these mediators. The current study was designed to examine the potential role of EDHF in human intestinal submucosal arterioles. ACh elicited endothelium-dependent relaxation in the presence of inhibitors of nitric oxide synthase and cyclooxygenase (23 +/- 10%, n = 6). This ACh-induced relaxation was inhibited and converted to constriction by catalase (-53 +/- 10%, n = 6) or KCl (-30 +/- 3%, n = 7), whereas 17-octadecynoic acid and 6-(2-propargylloxyphenyl) hexanoic acid, two inhibitors of cytochrome P450 monooxygenase, had no significant effect (3 +/- 1% and 20 +/- 8%, n = 5, respectively). Exogenous H(2)O(2) elicited dose-dependent relaxation of intact microvessels (52 +/- 10%, n = 7) but caused frank vasoconstriction in arterioles denuded of endothelium (-73 +/- 8%, n = 7). ACh markedly increased the dichlorofluorescein fluorescence in intact arterioles in the presence of nitric oxide synthase and cyclooxygenase inhibitors compared with control and compared with catalase-treated microvessels (363.6 +/- 49, 218.8 +/- 10.6, 221.9 +/- 27.9, respectively, P < 0.05 ANOVA, n = 5 arbitrary units). No changes in the dichlorofluorescein fluorescence were recorded in vessels treated with ACh alone. These results indicate that endothelial production of H(2)O(2) occurs in response to ACh in human gut mucosal arterioles but that H(2)O(2) is not an EDHF in this tissue. Rather, we speculate that it stimulates the release of a chemically distinct EDHF. PMID:15345486

Hatoum, Ossama A; Binion, David G; Miura, Hiroto; Telford, Gordon; Otterson, Mary F; Gutterman, David D

2004-09-02

298

Transport of Aflatoxin M(1) in Human Intestinal Caco-2/TC7 Cells.  

UK PubMed Central (United Kingdom)

Aflatoxin M(1) (AFM(1)) is a hydroxylated metabolite of aflatoxin B(1) (AFB(1)). After it is formed, it is secreted in the milk of mammals. Despite the potential risk of human exposure to AFM(1), data reported in literature on the metabolism, toxicity, and bioavailability of this molecule are limited and out of date. The aim of the present research was to study the absorption profile of AFM(1) and possible damage to tight junctions (TJ) of the intestinal Caco-2/TC7 clone grown on microporous filter supports. These inserts allowed for the separation of the apical and basolateral compartments which correspond to the in vivo lumen and the interstitial space/vascular systems of intestinal mucosa respectively. In this study, the Caco-2/TC7 cells were treated with different AFM(1) concentrations (10-10,000?ng/kg) for short (40?min) and long periods of time (48?h). The AFM(1) influx/efflux transport and effects on TJ were evaluated by measuring trans-epithelial electrical resistance and observing TJ protein (Zonula occludens-1 and occludin) localization. The results showed that: (i) when introduced to the apical and basolateral compartments, AFM(1) was poorly absorbed by the Caco-2/TC7 cells but its transport across the cell monolayer occurred very quickly (P(app) value of 105.10?±?7.98?cm/s?×?10(-6)). (ii) The integrity of TJ was not permanently compromised after exposure to the mycotoxin. Viability impairment or barrier damage did not occur either. The present results contribute to the evaluation of human risk exposure to AFM(1), although the AFM(1) transport mechanism need to be clarified.

Caloni F; Cortinovis C; Pizzo F; De Angelis I

2012-01-01

299

Use of stable isotopes to measure the metabolic activity of the human intestinal microbiota.  

UK PubMed Central (United Kingdom)

The human intestinal microbiota is a complex biological system comprising a vast repertoire of microbes with considerable metabolic activity relevant to both bacterial growth and host health. Greater strides have been made in the analysis of microbial diversity than in the measurement of functional activity, particularly in vivo. Stable isotope probing offers a new approach by coupling measurements of metabolic activity with microbial identification. Using a low-enrichment labeling strategy in vitro, this study has identified metabolically active bacterial groups via magnetic-bead capture methodology and stable isotope ratio analysis. Using five probes (EUB338, Bac303, Bif164, EREC482, and Clep866), changes in the activities of key intestinal microbial groups were successfully measured by exploiting tracers of de novo RNA synthesis. Perturbation of the nutrient source with oligofructose generated changes in the activity of bifidobacteria as expected, but also in the Bacteroides-Prevotella group, the Eubacterium rectale-Clostridium coccoides group, and the Clostridium leptum subgroup. Changes in activity were also observed in response to the medium type. This study suggests that changes in the functional activity of the gut microbiota can be assessed using tracers of de novo nucleic acid synthesis combined with measurement of low isotopic enrichment in 16S rRNA. Such tracers potentially limit substrate bias because they are universally available to bacteria. This low-enrichment labeling approach does not depend on the commercial availability of specific labeled substrates and can be easily translated to in vivo probing experiments of the functional activity of the microbiota in the human gut.

Reichardt N; Barclay AR; Weaver LT; Morrison DJ

2011-11-01

300

Leptin regulates sugar and amino acids transport in the human intestinal cell line Caco-2.  

UK PubMed Central (United Kingdom)

AIM: Studies in rodents have shown that leptin controls sugars and glutamine entry in the enterocytes by regulating membrane transporters. Here, we have examined the effect of leptin on sugar and amino acids absorption in the human model of intestinal cells Caco-2 and investigated the transporters involved. METHODS: Substrate uptake experiments were performed in Caco-2 cells, grown on plates, in the presence and the absence of leptin, and the expression of the different transporters in brush border membrane vesicles was analysed by Western blot. RESULTS: Leptin inhibited 0.1 mm ?-methyl-D-glucoside uptake after 5 or 30 min treatment and decreased SGLT1 protein abundance in the apical membrane. Uptake of 20 ?m glutamine and 0.1 mm phenylalanine was also inhibited by leptin, indicating sensitivity to the hormone of the Na(+) -dependent neutral amino acid transporters ASCT2 and B(0) AT1. This inhibition was accompanied by a reduction in the transporters expression at the brush border membrane. Leptin also inhibited 1 mm proline and ?-alanine uptake in Na(+) medium at pH 6, conditions for optimal activity of the H(+) -dependent neutral amino acid transporter PAT1. In this case, abundance of PAT1 in the brush border membrane after leptin treatment was not modified. Interestingly, leptin inhibitory effect on ?-alanine uptake was reversed by the PKA inhibitor H-89 suggesting involvement of PKA pathway in leptin's regulation of PAT1 activity. CONCLUSION: These data show in human intestinal cells that leptin can rapidly control the activity of physiologically relevant transporters for rich-energy molecules, that is, D-glucose (SGLT1) and amino acids (ASCT2, B(0) AT1 and PAT1).

Fanjul C; Barrenetxe J; Iñigo C; Sakar Y; Ducroc R; Barber A; Lostao MP

2012-05-01

 
 
 
 
301

Cholinergic interactions between donepezil and prucalopride in human colon: potential to treat severe intestinal dysmotility.  

UK PubMed Central (United Kingdom)

BACKGROUND AND PURPOSE: Cholinesterase inhibitors such as neostigmine are used for acute colonic pseudo-obstruction, but cardio-bronchial side-effects limit use. To minimise side-effects, lower doses could be combined with a 5-HT4 receptor agonist, which also facilitates intestinal cholinergic activity. However, safety concerns, especially in the elderly, require drugs with good selectivity of action. These include the acetylcholinesterase inhibitor donepezil (used for Alzheimer's disease, with reduced cardio-bronchial liability) and prucalopride, the first selective, clinically-available 5-HT4 receptor agonist. This study examined their individual and potential synergistic activities in human colon. EXPERIMENTAL APPROACH: Neuronally-mediated muscle contractions and relaxations of human colon were evoked by electrical field stimulation (EFS) and defined phenotypically as cholinergic, nitrergic or tachykinergic using pharmacological tools; the effects of drugs were determined as changes in 'area under the curve'. KEY RESULTS: Prucalopride increased cholinergically-mediated contractions (EC50 855 nM; 33% maximum increase), consistent with its ability to stimulate intestinal motility; donepezil (477%) and neostigmine (2326%) had greater efficacy. Concentrations of donepezil (30-100 nM) found in venous plasma after therapeutic doses had minimal ability to enhance cholinergic activity. However, donepezil (30 nM) together with prucalopride (3, 10 ?M) markedly increased EFS-evoked contractions compared to prucalopride alone (P=0.04). For example, the increases observed with donepezil and prucalopride 10 ?M together or alone were, respectively, 105 ± 35%, 4 ± 6% and 35 ± 21% (n=3-7, each concentration). CONCLUSIONS AND IMPLICATIONS: Potential synergy between prucalopride and donepezil activity calls for exploration of this combination as a safer, more effective treatment of colonic pseudo-obstruction.

Broad J; Kung VW; Boundouki G; Aziz Q; De Maeyer JH; Knowles CH; Sanger GJ

2013-09-01

302

Effect of hyoscine butylbromide (Buscopan®) on cholinergic pathways in the human intestine.  

UK PubMed Central (United Kingdom)

BACKGROUND: Hyoscine butylbromide (HBB, Buscopan(®) ) is clinically used to treat intestinal cramps and visceral pain. Various studies, mainly on animal tissues, suggested that its antimuscarinic action is responsible for its spasmolytic effect. However, functional in vitro studies with human tissue have not been performed so far. METHODS: We wanted to provide a comprehensive study on the mode of action of HBB in human intestinal samples and investigated HBB (1 nmol L(-1) -10 ?mol L(-1)) effects on muscle activity with isometric force transducers and calcium imaging, on epithelial secretion with Ussing chamber technique and on enteric neurons using fast neuroimaging. KEY RESULTS: Hyoscine butylbromide concentration dependently reduced muscle contractions, calcium mobilization, and epithelial secretion induced by the muscarinic agonist bethanechol with IC50 values of 429, 121, and 224 nmol L(-1), respectively. Forskolin-induced secretion was not altered by HBB. Cholinergic muscarinic muscle and epithelial responses evoked by electrical nerve stimulation were inhibited by 1-10 ?mol L(-1) HBB. Moreover, HBB significantly reduced the bethanechol-induced action potential discharge in enteric neurons. Interestingly, we observed that high concentrations of HBB (10 ?mol L(-1)) moderately decreased nicotinic receptor-mediated secretion, motility, and nerve activity. CONCLUSIONS & INFERENCES: The results demonstrated the strong antimuscarinic action of HBB whereas the nicotinic antagonism at higher concentrations plays at most a moderate modulatory role. The muscle relaxing effect of HBB and its inhibition of muscarinic nerve activation likely explain its clinical use as an antispasmodic drug. Our results further highlight a so far unknown antisecretory action of HBB which warrants further clinical studies on its use in secretory disorders.

Krueger D; Michel K; Allam S; Weiser T; Demir IE; Ceyhan GO; Zeller F; Schemann M

2013-08-01

303

The Influence of Different Apple Based Supplements on the Intestinal Microbiota of Humans.  

DEFF Research Database (Denmark)

Background and objective: The present project is part of the large ISAFRUIT project, where one of the objectives is to identify effects of apple and apple product on parameters related to gut health. In a previous rat study we observed changes in the intestinal microbiota of rats fed whole apples, pomace or apple pectin ([1], and we were interested in finding out if the same effect can be observed in humans. Method: The study was conducted as a randomized, controlled 5 x 28 days cross-over study with 24 healthy persons of both genders. The persons were following a pectin- and polyphenol free restriction diet during the control period, and in the four other periods it was supplied with four different apple based supplements. Between the diets there was a 2-week wash-out period still on the restriction diet. The four apple based supplements were: 1) whole apples, 2) clear apple juice (pectin-free), 3) cloudy juice (apple juice with pulp), and 4) pomace (press cake from the cloudy juice production process). Fecal samples were taken before and after each diet period. After DNA extraction, Denaturing Gradient Gel Electrophoresis (DGGE) with universal primers and specific primers for bifidobacteria and Clostridium cluster XIVa was performed. Bands differing between the periods were sequenced, and qPCR was performed to verify the changes observed by DGGE. Results: Changes in the microbiota was observed by DGGE in persons consuming whole apples and pomace. In contrast, the two juice supplements did not show any effect on the microbiota by DGGE. Conclusion: Consumption of whole apples or pomace is able to modify the intestinal microbiota of humans.

Bergström, Anders; Wilcks, Andrea

2010-01-01

304

Predicting the impact of diet and enzymopathies on human small intestinal epithelial cells.  

Science.gov (United States)

Small intestinal epithelial cells (sIECs) have a significant share in whole body metabolism as they perform enzymatic digestion and absorption of nutrients. Furthermore, the diet plays a key role in a number of complex diseases including obesity and diabetes. The impact of diet and altered genetic backgrounds on human metabolism may be studied by using computational modeling. A metabolic reconstruction of human sIECs was manually assembled using the literature. The resulting sIEC model was subjected to two different diets to obtain condition-specific metabolic models. Fifty defined metabolic tasks evaluated the functionalities of these models, along with the respective secretion profiles, which distinguished between impacts of different dietary regimes. Under the average American diet, the sIEC model resulted in higher secretion flux for metabolites implicated in metabolic syndrome. In addition, enzymopathies were analyzed in the context of the sIEC metabolism. Computed results were compared with reported gastrointestinal (GI) pathologies and biochemical defects as well as with biomarker patterns used in their diagnosis. Based on our simulations, we propose that (i) sIEC metabolism is perturbed by numerous enzymopathies, which can be used to study cellular adaptive mechanisms specific for such disorders, and in the identification of novel co-morbidities, (ii) porphyrias are associated with both heme synthesis and degradation and (iii) disturbed intestinal gamma-aminobutyric acid synthesis may be linked to neurological manifestations of various enzymopathies. Taken together, the sIEC model represents a comprehensive, biochemically accurate platform for studying the function of sIEC and their role in whole body metabolism. PMID:23492669

Sahoo, Swagatika; Thiele, Ines

2013-03-13

305

Predicting the impact of diet and enzymopathies on human small intestinal epithelial cells.  

UK PubMed Central (United Kingdom)

Small intestinal epithelial cells (sIECs) have a significant share in whole body metabolism as they perform enzymatic digestion and absorption of nutrients. Furthermore, the diet plays a key role in a number of complex diseases including obesity and diabetes. The impact of diet and altered genetic backgrounds on human metabolism may be studied by using computational modeling. A metabolic reconstruction of human sIECs was manually assembled using the literature. The resulting sIEC model was subjected to two different diets to obtain condition-specific metabolic models. Fifty defined metabolic tasks evaluated the functionalities of these models, along with the respective secretion profiles, which distinguished between impacts of different dietary regimes. Under the average American diet, the sIEC model resulted in higher secretion flux for metabolites implicated in metabolic syndrome. In addition, enzymopathies were analyzed in the context of the sIEC metabolism. Computed results were compared with reported gastrointestinal (GI) pathologies and biochemical defects as well as with biomarker patterns used in their diagnosis. Based on our simulations, we propose that (i) sIEC metabolism is perturbed by numerous enzymopathies, which can be used to study cellular adaptive mechanisms specific for such disorders, and in the identification of novel co-morbidities, (ii) porphyrias are associated with both heme synthesis and degradation and (iii) disturbed intestinal gamma-aminobutyric acid synthesis may be linked to neurological manifestations of various enzymopathies. Taken together, the sIEC model represents a comprehensive, biochemically accurate platform for studying the function of sIEC and their role in whole body metabolism.

Sahoo S; Thiele I

2013-07-01

306

In vitro behavior of human intestinal mucosa. The influence of acetyl choline on ion transport.  

UK PubMed Central (United Kingdom)

The possibility that the autonomic nervous system may influence the function of intestinal mucosa was investigated by assessing the effect of acetyl choline on ion transport in human intestine. Isolated pieces of stripped ileal mucosa were mounted in Perspex flux-chambers and bathed in isotonic glucose Ringer's solution. Acetyl choline caused a rise in mean potential difference (8.8-12.3 mV, P less than 0.002) and short circuit current (287.7-417.2 muA-cm-2, P less than 0.01) (n = 12), observable at a concentration of 0.01 mM and maximal at 0.1 mM. This effect was enhanced by neostigmine and blocked by atropine. Isotopic flux determinations revealed a change from a small mean net Cl absorption (58) to a net Cl secretion (-4.3mueq-cm-2-h-1P less than 0.001) due predominantly to an increase in the serosal to mucosal unidirectional flux of Cl (10.63-14.35 mueq-cm-2-h-1P less than 0.05) and a smaller reduction in the mucosal to serosal flux (11.22 to 10.02 mueq-cm-2-h-1P less than 0.05). Unidirectional and net Na transport was unaffected. A similar electrical and ion transport response was observed in a single study of two pieces of jejunal mucosa. In the absence of glucose net chloride secretion was produced and again an insignificant effect on net sodium transport was noted. Acetyl choline did not provoke a sustained effect on mucosal cyclic adenine nucleotide levels although a short-lived cyclic adenine nucleotide response was seen in some tissues 20-30 s after drug addition. These studies demonstrate that acetyl choline does influence human intestinal ion transport by stimulating chloride secretion and suggest a possible mechanism by which the parasympathetic nervous system could be concerned in the control of ion transport.

Isaacs PE; Corbett CL; Riley AK; Hawker PC; Turnberg LA

1976-09-01

307

EGF signaling activates proliferation and blocks apoptosis of mouse and human intestinal stem/progenitor cells in long-term monolayer cell culture.  

UK PubMed Central (United Kingdom)

The homeostatic renewal of the intestinal epithelium depends on regulation of proliferation and differentiation of stem/progenitor cells residing in a specific site, called the 'stem cell niche.' Thus, the reconstitution of the microenvironment of the stem cell niche may allow us to maintain intestinal stem/progenitor cells in culture for a longer period. Although epidermal growth factor (EGF) is conventionally used as a supplement of intestinal epithelial cell culture, little has been known regarding a role of EGF signaling in a stem/progenitor cell population. In this study, we attempted to clarify the role of EGF signaling in intestinal stem/progenitor cells, and to establish a culture system in which these cells could be maintained with normal differentiation potential. We first examined the expression pattern of EGF and its receptor, EGFR, and inhibited EGF signaling in mouse intestines. Next, we cultured intestinal cells isolated from mouse and human intestines in the presence of EGF and analyzed the function of EGF signaling in cultured cells. In both embryonic and adult mouse intestines, EGFR and EGF were expressed in immature epithelial cells and adjacent fibroblasts, respectively, and EGF signaling was essential to activate proliferation and inhibit apoptosis of intestinal stem/progenitor cells. Activation of EGF signaling also stimulated proliferation and suppressed apoptosis, both of which are necessary to maintain mouse and human intestinal epithelial cells in culture. Moreover, in these cultured epithelial cells, putative intestinal stem/progenitor cells persisted longer, and gave rise to different types of differentiated intestinal epithelial cells. We conclude that EGF signaling is indispensable for activation of proliferation and inhibition of unexpected cell death, not only in the intestinal stem cell niche, but also in culture of primitive intestinal epithelial cells.

Suzuki A; Sekiya S; Gunshima E; Fujii S; Taniguchi H

2010-10-01

308

Fructose transporter in human spermatozoa and small intestine is GLUT5.  

UK PubMed Central (United Kingdom)

We recently reported that the glucose transporter isoform, GLUT5, is expressed on the brush border membrane of human small intestinal enterocytes (Davidson, N. O., Hausman, A. M. L., Ifkovits, C. A., Buse, J. B., Gould, G. W., Burant, C. F., and Bell, G. I. (1992) Am. J. Physiol. 262, C795-C800). To define its role in sugar transport, human GLUT5 was expressed in Xenopus oocytes and its substrate specificity and kinetic properties determined. GLUT5 exhibits selectivity for fructose transport, as determined by inhibition studies, with a Km of 6 mM. In addition, fructose transport by GLUT5 is not inhibited by cytochalasin B, a competitive inhibitor of facilitative glucose transporters. RNA and protein blotting studies showed the presence of high levels of GLUT5 mRNA and protein in human testis and spermatozoa, and immunocytochemical studies localize GLUT5 to the plasma membrane of mature spermatids and spermatozoa. The biochemical properties and tissue distribution of GLUT5 are consistent with a physiological role for this protein as a fructose transporter.

Burant CF; Takeda J; Brot-Laroche E; Bell GI; Davidson NO

1992-07-01

309

Fructose transporter in human spermatozoa and small intestine is GLUT5.  

Science.gov (United States)

We recently reported that the glucose transporter isoform, GLUT5, is expressed on the brush border membrane of human small intestinal enterocytes (Davidson, N. O., Hausman, A. M. L., Ifkovits, C. A., Buse, J. B., Gould, G. W., Burant, C. F., and Bell, G. I. (1992) Am. J. Physiol. 262, C795-C800). To define its role in sugar transport, human GLUT5 was expressed in Xenopus oocytes and its substrate specificity and kinetic properties determined. GLUT5 exhibits selectivity for fructose transport, as determined by inhibition studies, with a Km of 6 mM. In addition, fructose transport by GLUT5 is not inhibited by cytochalasin B, a competitive inhibitor of facilitative glucose transporters. RNA and protein blotting studies showed the presence of high levels of GLUT5 mRNA and protein in human testis and spermatozoa, and immunocytochemical studies localize GLUT5 to the plasma membrane of mature spermatids and spermatozoa. The biochemical properties and tissue distribution of GLUT5 are consistent with a physiological role for this protein as a fructose transporter. PMID:1634504

Burant, C F; Takeda, J; Brot-Laroche, E; Bell, G I; Davidson, N O

1992-07-25

310

Differential Modulation of Human Intestinal Bifidobacterium Populations after Consumption of a Wild Blueberry ( Vaccinium angustifolium ) Drink.  

Science.gov (United States)

Bifidobacteria are gaining increasing interest as health-promoting bacteria. Nonetheless, the genus comprises several species, which can exert different effects on human host. Previous studies showed that wild blueberry drink consumption could selectively increase intestinal bifidobacteria, suggesting an important role for the polyphenols and fiber present in wild blueberries. This study evaluated the modulation of the most common and abundant bifidobacterial taxonomic groups inhabiting the human gut in the same fecal samples. The analyses carried out showed that B. adolescentis , B. breve , B. catenulatum / pseudocatelulatum , and B. longum subsp. longum were always present in the group of subjects enrolled, whereas B. bifidum and B. longum subsp. infantis were not. Furthermore, it was found that the most predominant bifidobacterial species were B. longum subsp. longum and B. adolescentis. The results obtained revealed a high interindividual variability; however, a significant increase of B. longum subsp. infantis cell concentration was observed in the feces of volunteers after the wild blueberry drink treatment. This bifidobacterial group was shown to possess immunomodulatory abilities and to relieve symptoms and promote the regression of several gastrointestinal disorders. Thus, an increased cell concentration of B. longum subsp. infantis in the human gut could be considered of potential health benefit. In conclusion, wild blueberry consumption resulted in a specific bifidogenic effect that could positively affect certain populations of bifidobacteria with demonstrated health-promoting properties. PMID:23883473

Guglielmetti, Simone; Fracassetti, Daniela; Taverniti, Valentina; Del Bo', Cristian; Vendrame, Stefano; Klimis-Zacas, Dorothy; Arioli, Stefania; Riso, Patrizia; Porrini, Marisa

2013-08-19

311

Differential Modulation of Human Intestinal Bifidobacterium Populations after Consumption of a Wild Blueberry ( Vaccinium angustifolium ) Drink.  

UK PubMed Central (United Kingdom)

Bifidobacteria are gaining increasing interest as health-promoting bacteria. Nonetheless, the genus comprises several species, which can exert different effects on human host. Previous studies showed that wild blueberry drink consumption could selectively increase intestinal bifidobacteria, suggesting an important role for the polyphenols and fiber present in wild blueberries. This study evaluated the modulation of the most common and abundant bifidobacterial taxonomic groups inhabiting the human gut in the same fecal samples. The analyses carried out showed that B. adolescentis , B. breve , B. catenulatum / pseudocatelulatum , and B. longum subsp. longum were always present in the group of subjects enrolled, whereas B. bifidum and B. longum subsp. infantis were not. Furthermore, it was found that the most predominant bifidobacterial species were B. longum subsp. longum and B. adolescentis. The results obtained revealed a high interindividual variability; however, a significant increase of B. longum subsp. infantis cell concentration was observed in the feces of volunteers after the wild blueberry drink treatment. This bifidobacterial group was shown to possess immunomodulatory abilities and to relieve symptoms and promote the regression of several gastrointestinal disorders. Thus, an increased cell concentration of B. longum subsp. infantis in the human gut could be considered of potential health benefit. In conclusion, wild blueberry consumption resulted in a specific bifidogenic effect that could positively affect certain populations of bifidobacteria with demonstrated health-promoting properties.

Guglielmetti S; Fracassetti D; Taverniti V; Del Bo' C; Vendrame S; Klimis-Zacas D; Arioli S; Riso P; Porrini M

2013-08-01

312

Role of commercial probiotic strains against human pathogen adhesion to intestinal mucus.  

UK PubMed Central (United Kingdom)

AIMS: The aims of this study present were to assess and to evaluate in vitro the abilities of commercial probiotic strains derived from fermented milk products and related sources currently marketed in European countries, to inhibit, compete and displace the adhesion of selected potential pathogens to immobilized human mucus. METHODS AND RESULTS: The adhesion was assessed by measuring the radioactivity of bacteria adhered to the human mucus. We tested 12 probiotic strains against eight selected pathogens. All strains tested were able to adhere to mucus. All probiotic strains tested were able to inhibit and displace (P<0.05) the adhesion of Bacteroides, Clostridium, Staphylococcus and Enterobacter. In addition, the abilities to inhibit and to displace adhered pathogens depended on both the probiotic and the pathogen strains tested suggesting that several complementary mechanisms are implied in the processes. CONCLUSIONS: Our results indicate the need for a case-by-case assessment in order to select strains with the ability to inhibit or displace a specific pathogen. Probiotics could be useful to correct deviations observed in intestinal microbiota associated with specific diseases and also, to prevent pathogen infections. SIGNIFICANCE AND IMPACT OF THE STUDY: The competitive exclusion properties of probiotics as well as their ability to displace and inhibit pathogens are the most importance for therapeutic manipulation of the enteric microbiota. The application of such strategies could contribute to expand the beneficial properties on human health against pathogen infection.

Collado MC; Meriluoto J; Salminen S

2007-10-01

313

Transition state analysis of thymidine hydrolysis by human thymidine phosphorylase.  

UK PubMed Central (United Kingdom)

Human thymidine phosphorylase (hTP) is responsible for thymidine (dT) homeostasis, and its action promotes angiogenesis. In the absence of phosphate, hTP catalyzes a slow hydrolytic depyrimidination of dT yielding thymine and 2-deoxyribose (dRib). Its transition state was characterized using multiple kinetic isotope effect (KIE) measurements. Isotopically enriched thymidines were synthesized enzymatically from glucose or (deoxy)ribose, and intrinsic KIEs were used to interpret the transition state structure. KIEs from [1'-(14)C]-, [1-(15)N]-, [1'-(3)H]-, [2'R-(3)H]-, [2'S-(3)H]-, [4'-(3)H]-, and [5'-(3)H]dTs provided values of 1.033 ± 0.002, 1.004 ± 0.002, 1.325 ± 0.003, 1.101 ± 0.004, 1.087 ± 0.005, 1.040 ± 0.003, and 1.033 ± 0.003, respectively. Transition state analysis revealed a stepwise mechanism with a 2-deoxyribocation formed early and a higher energetic barrier for nucleophilic attack of a water molecule on the high energy intermediate. An equilibrium exists between the deoxyribocation and reactants prior to the irreversible nucleophilic attack by water. The results establish activation of the thymine leaving group without requirement for phosphate. A transition state constrained to match the intrinsic KIEs was found using density functional theory. An active site histidine (His116) is implicated as the catalytic base for activation of the water nucleophile at the rate-limiting transition state. The distance between the water nucleophile and the anomeric carbon (r(C-O)) is predicted to be 2.3 A at the transition state. The transition state model predicts that deoxyribose adopts a mild 3'-endo conformation during nucleophilic capture. These results differ from the concerted bimolecular mechanism reported for the arsenolytic reaction (Birck, M. R.; Schramm, V. L. J. Am. Chem. Soc. 2004, 126, 2447-2453).

Schwartz PA; Vetticatt MJ; Schramm VL

2010-09-01

314

Transition state analysis of thymidine hydrolysis by human thymidine phosphorylase.  

Science.gov (United States)

Human thymidine phosphorylase (hTP) is responsible for thymidine (dT) homeostasis, and its action promotes angiogenesis. In the absence of phosphate, hTP catalyzes a slow hydrolytic depyrimidination of dT yielding thymine and 2-deoxyribose (dRib). Its transition state was characterized using multiple kinetic isotope effect (KIE) measurements. Isotopically enriched thymidines were synthesized enzymatically from glucose or (deoxy)ribose, and intrinsic KIEs were used to interpret the transition state structure. KIEs from [1'-(14)C]-, [1-(15)N]-, [1'-(3)H]-, [2'R-(3)H]-, [2'S-(3)H]-, [4'-(3)H]-, and [5'-(3)H]dTs provided values of 1.033 ± 0.002, 1.004 ± 0.002, 1.325 ± 0.003, 1.101 ± 0.004, 1.087 ± 0.005, 1.040 ± 0.003, and 1.033 ± 0.003, respectively. Transition state analysis revealed a stepwise mechanism with a 2-deoxyribocation formed early and a higher energetic barrier for nucleophilic attack of a water molecule on the high energy intermediate. An equilibrium exists between the deoxyribocation and reactants prior to the irreversible nucleophilic attack by water. The results establish activation of the thymine leaving group without requirement for phosphate. A transition state constrained to match the intrinsic KIEs was found using density functional theory. An active site histidine (His116) is implicated as the catalytic base for activation of the water nucleophile at the rate-limiting transition state. The distance between the water nucleophile and the anomeric carbon (r(C-O)) is predicted to be 2.3 A at the transition state. The transition state model predicts that deoxyribose adopts a mild 3'-endo conformation during nucleophilic capture. These results differ from the concerted bimolecular mechanism reported for the arsenolytic reaction (Birck, M. R.; Schramm, V. L. J. Am. Chem. Soc. 2004, 126, 2447-2453). PMID:20804144

Schwartz, Phillip A; Vetticatt, Mathew J; Schramm, Vern L

2010-09-29

315

A comparative analysis of the intestinal metagenomes present in guinea pigs (Cavia porcellus) and humans (Homo sapiens).  

UK PubMed Central (United Kingdom)

BACKGROUND: Guinea pig (Cavia porcellus) is an important model for human intestinal research. We have characterized the faecal microbiota of 60 guinea pigs using Illumina shotgun metagenomics, and used this data to compile a gene catalogue of its prevalent microbiota. Subsequently, we compared the guinea pig microbiome to existing human gut metagenome data from the MetaHIT project. RESULTS: We found that the bacterial richness obtained for human samples was lower than for guinea pig samples. The intestinal microbiotas of both species were dominated by the two phyla Bacteroidetes and Firmicutes, but at genus level, the majority of identified genera (320 of 376) were differently abundant in the two hosts. For example, the guinea pig contained considerably more of the mucin-degrading Akkermansia, as well as of the methanogenic archaea Methanobrevibacter than found in humans. Most microbiome functional categories were less abundant in guinea pigs than in humans. Exceptions included functional categories possibly reflecting dehydration/rehydration stress in the guinea pig intestine. Finally, we showed that microbiological databases have serious anthropocentric biases, which impacts model organism research. CONCLUSIONS: The results lay the foundation for future gastrointestinal research applying guinea pigs as models for humans.

Hildebrand F; Ebersbach T; Nielsen HB; Li X; Sonne SB; Bertalan M; Dimitrov P; Madsen L; Qin J; Wang J; Raes J; Kristiansen K; Licht TR

2012-01-01

316

Biotransformation of 1-nitropyrene to 1-aminopyrene and N-formyl-1-aminopyrene by the human intestinal microbiota  

Energy Technology Data Exchange (ETDEWEB)

The nitropolycyclic aromatic hydrocarbon 1-nitropyrene (1-NP) is an environmental pollutant, a potent bacterial and mammalian mutagen, and a carcinogen. The metabolism of 1-NP by the human intestinal microbiota was studied using a semicontinuous culture system that simulates the colonic lumen. (/sup 3/H)-1-Nitropyrene was metabolized by the intestinal microbiota to 1-aminopyrene (1-AP) and N-formyl-1-aminopyrene (FAP) as determined by high-performance liquid chromatography (HPLC) and mass spectrometry. Twenty-four hours after the addition of (/sup 3/H)-1-NP, the formylated compound and 1-AP accounted for 20 and 80% of the total metabolism respectively. This percentage increased to 66% for FAP after 24 h following 10 d of chronic exposure to unlabeled 1-NP, suggesting metabolic adaptation to 1-NP by the microbiota. Both 1-AP and FAP have been shown to be nonmutagenic towards Salmonella typhimurium TA98, which indicates that the intestinal microflora may potentially detoxify 1-NP.

Manning, B.W.; Cerniglia, C.E.; Federle, T.W.

1986-01-01

317

Biotransformation of 1-nitropyrene to 1-aminopyrene and N-formyl-1-aminopyrene by the human intestinal microbiota  

International Nuclear Information System (INIS)

[en] The nitropolycyclic aromatic hydrocarbon 1-nitropyrene (1-NP) is an environmental pollutant, a potent bacterial and mammalian mutagen, and a carcinogen. The metabolism of 1-NP by the human intestinal microbiota was studied using a semicontinuous culture system that simulates the colonic lumen. [3H]-1-Nitropyrene was metabolized by the intestinal microbiota to 1-aminopyrene (1-AP) and N-formyl-1-aminopyrene (FAP) as determined by high-performance liquid chromatography (HPLC) and mass spectrometry. Twenty-four hours after the addition of [3H]-1-NP, the formylated compound and 1-AP accounted for 20 and 80% of the total metabolism respectively. This percentage increased to 66% for FAP after 24 h following 10 d of chronic exposure to unlabeled 1-NP, suggesting metabolic adaptation to 1-NP by the microbiota. Both 1-AP and FAP have been shown to be nonmutagenic towards Salmonella typhimurium TA98, which indicates that the intestinal microflora may potentially detoxify 1-NP

1986-01-01

318

Solution structure of human intestinal fatty acid binding protein: Implications for ligand entry and exit  

International Nuclear Information System (INIS)

[en] The human intestinal fatty acid binding protein (I-FABP) is a small (131 amino acids) protein which binds dietary long-chain fatty acids in the cytosol of enterocytes. Recently, an alanine to threonine substitution at position 54 in I-FABP has been identified which affects fatty acid binding and transport, and is associated with the development of insulin resistance in several populations including Mexican-Americans and Pima Indians. To investigate the molecular basis of the binding properties of I-FABP, the 3D solution structure of the more common form of human I-FABP (Ala54) was studied by multidimensional NMR spectroscopy.Recombinant I-FABP was expressed from E. coli in the presence and absence of 15N-enriched media. The sequential assignments for non-delipidated I-FABP were completed by using 2D homonuclear spectra (COSY, TOCSY and NOESY) and 3D heteronuclear spectra(NOESY-HMQC and TOCSY-HMQC). The tertiary structure of human I-FABP was calculated by using the distance geometry program DIANA based on 2519 distance constraints obtained from the NMR data. Subsequent energy minimization was carried out by using the program SYBYL in the presence of distance constraints. The conformation of human I-FABP consists of 10 antiparallel ?-strands which form two nearly orthogonal ?-sheets of five strands each, and two short ?-helices that connect the ?-strands A and B. The interior of the protein consists of a water-filled cavity between the two ?-sheets. The NMR solution structure of human I-FABP is similar to the crystal structure of rat I-FABP.The NMR results show significant conformational variability of certain backbone segments around the postulated portal region for the entry and exit of fatty acid ligand

1997-01-01

319

Solution structure of human intestinal fatty acid binding protein: Implications for ligand entry and exit  

Energy Technology Data Exchange (ETDEWEB)

The human intestinal fatty acid binding protein (I-FABP) is a small (131 amino acids) protein which binds dietary long-chain fatty acids in the cytosol of enterocytes. Recently, an alanine to threonine substitution at position 54 in I-FABP has been identified which affects fatty acid binding and transport, and is associated with the development of insulin resistance in several populations including Mexican-Americans and Pima Indians. To investigate the molecular basis of the binding properties of I-FABP, the 3D solution structure of the more common form of human I-FABP (Ala54) was studied by multidimensional NMR spectroscopy.Recombinant I-FABP was expressed from E. coli in the presence and absence of 15N-enriched media. The sequential assignments for non-delipidated I-FABP were completed by using 2D homonuclear spectra (COSY, TOCSY and NOESY) and 3D heteronuclear spectra(NOESY-HMQC and TOCSY-HMQC). The tertiary structure of human I-FABP was calculated by using the distance geometry program DIANA based on 2519 distance constraints obtained from the NMR data. Subsequent energy minimization was carried out by using the program SYBYL in the presence of distance constraints. The conformation of human I-FABP consists of 10 antiparallel {beta}-strands which form two nearly orthogonal {beta}-sheets of five strands each, and two short {alpha}-helices that connect the {beta}-strands A and B. The interior of the protein consists of a water-filled cavity between the two {beta}-sheets. The NMR solution structure of human I-FABP is similar to the crystal structure of rat I-FABP.The NMR results show significant conformational variability of certain backbone segments around the postulated portal region for the entry and exit of fatty acid ligand.

Zhang Fengli [Boston University School of Medicine, Department of Biophysics (United States); Luecke, Christian [Johann Wolfgang Goethe-Universitaet (Germany); Baier, Leslie J. [NIDDK, NIH, Phoenix Epidemiology and Clinical Research Branch (United States); Sacchettini, James C. [Texas A and M University, Department of Biochemistry and Biophysics (United States); Hamilton, James A. [Boston University School of Medicine, Department of Biophysics (United States)

1997-04-15

320

Interleukin-13 and transforming growth factor ? synergise in the pathogenesis of human intestinal fistulae.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Epithelial to mesenchymal transition (EMT) seems to play an important role in the pathogenesis of fistulae, a common clinical complication of Crohn's disease (CD). TGF? and interleukin-13 (IL-13) have been correlated with the onset of EMT-associated organ fibrosis and high levels of TGF? have been shown in transitional cells (TCs) lining CD fistula tracts. This study investigated whether IL-13 could be involved in the pathogenesis of CD-associated fistulae. DESIGN: Protein or mRNA levels in HT29 intestinal epithelial cells (IECs) or colonic lamina propria fibroblasts (CLPFs) were studied by western blotting or real-time PCR. CLPFs were isolated from non-inflammatory disease controls or patients with CD with or without fistulae and IL-13 levels were analysed in surgically removed fistula specimens by immunohistochemistry. RESULTS: TGF? induced IL-13 secretion in CLPFs from patients with fistulising CD. In fistula specimens high levels of IL-13 were detected in TCs covering fistula tracts. In HT29 IEC monolayers, IL-13 induced SLUG and ?6-integrin mRNA, which are associated with cell invasion. HT29 spheroids completely disintegrated when treated with TGF? for 7 days, whereas IL-13-treated spheroids did not show morphological changes. Here, TGF? induced mRNA expression of SNAIL1 and IL-13, whereas IL-13 elevated SLUG and ?6-integrin mRNA. An anti-IL-13 antibody was able to prevent IL-13-induced SLUG expression in HT29 IECs. CONCLUSIONS: TGF? induces IL-13 expression and an EMT-like phenotype of IECs, while IL-13 promotes the expression of genes associated with cell invasion. These findings suggest that TGF? and IL-13 play a synergistic role in the pathogenesis of fistulae and inhibition of IL-13 might represent a novel therapeutic approach for fistula treatment.

Scharl M; Frei S; Pesch T; Kellermeier S; Arikkat J; Frei P; Fried M; Weber A; Jehle E; Rühl A; Rogler G

2013-01-01

 
 
 
 
321

Effect of absorbable and nonabsorbable sugars on intestinal calcium absorption in humans  

International Nuclear Information System (INIS)

The effects of glucose, galactose, and lactitol on intestinal calcium absorption and gastric emptying were studied in 9, 8, and 20 healthy subjects, respectively. Calcium absorption was measured by using a double-isotope technique and the kinetic parameters were obtained by a deconvolution method. The gastric emptying rate was determined with /sup 99m/Tc-diethylenetriaminepentaacetic acid and was expressed as the half-time of the emptying curve. Each subject was studied under two conditions: (a) with calcium alone and (b) with calcium plus sugar. Glucose and galactose increased the calcium mean transit time and improved the total fractional calcium absorption by 30% (p less than 0.02). Lactitol decreased the mean rate of absorption (p less than 0.001) and reduced the total fractional calcium absorption by 15% (p less than 0.001). The gastric emptying rate did not appear to influence directly the kinetic parameters of calcium absorption. These results show that both glucose and galactose exert the same stimulatory effect as lactose on calcium absorption in subjects with normal lactase whereas lactitol mimics the effects of lactose in lactase-deficient patients. Thus the absorbability of sugars determines their effect on calcium absorption

1989-01-01

322

Characterization of cadmium uptake in human intestinal crypt cells HIEC in relation to inorganic metal speciation  

International Nuclear Information System (INIS)

Cadmium (Cd) uptake was studied under inorganic exposure conditions in normal human intestinal crypt cells HIEC. The uptake time course of 0.3?M Cd in a serum-free chloride medium was analyzed according to a first order equation with rapid initial (U0) and maximal (Umax) accumulation values of 14.1+/-1.4pmol/mgprotein and 41.4+/-2.0pmol/mgprotein, respectively. The presence of a 300-fold excess of unlabeled Cd dramatically decreased tracer uptake, showing the involvement of specific mechanism(s) of transport. Our speciation studies revealed the preferential uptake of the free ion Cd2+, but also suggested that CdCln2-n species may contribute to Cd accumulation. Specific mechanisms of transport of very high and similar affinity (Km?5?M) have been characterized under both chloride and nitrate exposure conditions, but a two-fold higher capacity (Vmax) was estimated in the nitrate medium used to increase [Cd2+] over chlorocomplex formation. A clear inhibition of 109Cd uptake was observed at external acidic pH under both exposure media. An La-inhibitible 46% increase in 109Cd uptake was obtained in nominally Ca-free nitrate medium, whereas Zn provided additional inhibition. These results show different kinetic parameters for Cd uptake as a function of inorganic metal speciation. Cd2+ uptake would not involve the H+-coupled symport NRAMP2 but would be related instead to the Ca and/or Zn pathways. Because proliferative crypt cells play a critical role in the renewal process of the entire intestinal epithelium, studies on the impact of Cd on HIEC cell functions clearly deserve further investigation.

2006-02-15

323

Epidemiology of human fascioliasis and intestinal parasitosis among schoolchildren in Lake Tana Basin, northwest Ethiopia.  

UK PubMed Central (United Kingdom)

BACKGROUND: Parasitic diseases are the second most frequent cause of outpatient morbidity in Ethiopia. METHODS: A cross-sectional study was conducted in Lake Tana Basin, northwest Ethiopia, from November 2007 to February 2008, to assess the magnitude and associated risk factors for parasitic diseases, including human fascioliasis. We examined 520 stool samples from randomly selected schoolchildren in six schools by microscopy. Rapid sedimentation and Kato-Katz techniques were used to detect and count Fasciola and Schistosoma eggs. The formol-ether concentration method was used for the identification of other helminth eggs, larvae and cysts of protozoan parasites. RESULTS: The overall prevalence of intestinal parasitic infections was 71.3% (95% CI 67.3-75.1%). Hookworm was the predominant intestinal parasite (23.5%, 95% CI 19.8-27.1%), followed by Ascaris lumbricoides (18.5%, 95% CI 15.2-21.9%) and Schistosoma mansoni (16.7%, 95% CI 13.5-19.9%). One hundred and sixty-three (31.4%) children had multiple parasitic infections. The most relevant finding was a prevalence of Fasciola spp. of 3.3% in an area where only sporadic cases have been reported previously. The risk of Fasciola spp. infection was significantly associated with raw vegetable consumption, use of unsafe drinking water sources, irrigation practices and sheep and/or cattle ownership. Irrigation practices, male gender, raw vegetable consumption and use of unsafe drinking water sources were risk factors for S. mansoni infection. CONCLUSIONS: A high prevalence of parasitic infections among children in the region was found, including a relatively high prevalence of Fasciola spp. infection. Epidemiological studies on the magnitude of parasitic infections in different regions will enable high-risk communities to be identified and allow for planning of appropriate interventions.

Fentie T; Erqou S; Gedefaw M; Desta A

2013-08-01

324

E Durans Strain M4-5 Isolated From Human Colonic Flora Attenuates Intestinal Inflammation  

DEFF Research Database (Denmark)

PURPOSE: The aim of this study was to evaluate in vitro and in vivo effects of a unique high-butyrate-producing bacterial strain from human colonic flora, Enterococcus durans, in prevention and treatment of intestinal inflammation. METHODS: A compartmentalized Caco-2/leukocyte coculture model was used to examine the in vitro effects of E durans and its metabolite butyrate on basal and Escherichia coli–stimulated secretion of proinflammatory immune factors (IL-8, IL-6, and TNF-?) and the anti-inflammatory cytokine IL-10. A murine model of dextran sodium sulfate-induced colitis was used to examine in vivo effects of prevention and therapy with E durans on clinical, biochemical, and histologic parameters of inflammation. RESULTS: In the coculture model, treatment with E durans and with butyrate reduced basal as well as E coli stimulated secretion of IL-8, IL-6, and TNF-? and increased secretion of IL-10. In the in vivo murine model, preventive administration of E durans significantly ameliorated clinical disease activity index (weight loss, fecal bleeding, and stool consistency), reduced myeloperoxidase concentration in colon tissue extracts, improved histologic scores of colonic inflammation, and inhibited colonic transcription of proinflammatory immune factors. The effect of therapeutic treatment alone on these parameters was more moderate but still significant. CONCLUSIONS: We conclude that E durans strain M4 to 5 and its metabolic product butyrate induce significant anti-inflammatory effects, mediated by regulation of pro- and anti-inflammatory immune factors as well as preservation of intestine epithelial integrity, suggesting that this novel anti-inflammatory bacterium may be preferentially a useful prophylactic treatment to avoid inflammatory bowel disease.

Avram-Hananel, L.; Stock, J.

2010-01-01

325

Artículos originales Cultivo primario de queratinocitos humanos sembrados en submucosa intestinal porcina/ Primary culture of human keratinocytes planted on pig?s intestine Submucosa  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish En el campo de la regeneración de piel, la ingeniería de tejidos busca superar las limitaciones asociadas con el uso de autoinjertos inmediatos, dado que la elección de una región donante en el paciente, constituye un riesgo para el mismo, además de ser insuficiente cuando la lesión es extensa. Se ha comprobado que el empleo de la submucosa del intestino delgado de cerdo (SIS) (por la sigla en inglés small intestinal submucosa), por su especial composición, como b (more) iomaterial de relleno para tratar lesiones, disminuye el dolor y la inflamación desde su primera aplicación y favorece la movilidad temprana de la región lesionada. Con el fin de determinar la utilidad de SIS, como sustituto epidérmico, en el presente estudio se desarrolló un protocolo para el cultivo primario de queratinocitos humanos, provenientes de prepucios infantiles, sobre una matriz de SIS como soporte. Se evaluó el potencial de adherencia y la capacidad de proliferación de queratinocitos sobre este sustrato. Abstract in english Tissue engineering, in the fields of skin regeneration, seeks to overcome the limitations associated with the use of immediate auto-grafts, since choosing the donor region of the patient constitutes a risk for the patient himself and is insufficient if the injury that has to be repaired is very large. The use of the pig?s small intestine submucosa (SIS) has being proved as a filling biomaterial to treat injuries, because of its special composition, it lowers pain and inf (more) lammation since its first application and it favours early mobility to the wounded area. The present study developed a protocol for the primary culture of human keratinocytes from infant foreskins, and used small intestinal submucosa (SIS) like culture substrate. Cellular adherence potential and proliferation capability of the keratinocytes over this substrate was evaluated.

Amórtegui, Ángela Ximena; Ramírez, Sandra Rocío

2008-12-01

326

Role of metabolism by the human intestinal microflora in arbutin-induced cytotoxicity in HepG2 cell cultures.  

UK PubMed Central (United Kingdom)

A possible role for metabolism by the human intestinal microflora in arbutin-induced cytotoxicity was investigated using human hepatoma HepG2 cells. When the cytotoxic effects of arbutin and hydroquinone (HQ), a deglycosylated metabolite of arbutin, were compared, HQ was more toxic than arbutin. Incubation of arbutin with a human fecal preparation could produce HQ. Following incubation of arbutin with a human fecal preparation for metabolic activation, the reaction mixture was filter-sterilized to test its toxic effects on HepG2 cells. The mixture induced cytotoxicity in HepG2 cells in a concentration-dependent manner. In addition, the mixture considerably inhibited expression of Bcl-2 together with an increase in Bax expression. Likewise, activation stimulated cleavage of caspase-3 and production of reactive oxygen species in HepG2 cell cultures. Furthermore, induction of apoptosis by the intestinal microflora reaction mixture was confirmed by the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick-end labeling assay. Taken together, these findings suggest that the human intestinal microflora is capable of metabolizing arbutin to HQ, which can induce apoptosis in mammalian cells.

Khanal T; Kim HG; Hwang YP; Kong MJ; Kang MJ; Yeo HK; Kim DH; Jeong TC; Jeong HG

2011-09-01

327

Role of metabolism by the human intestinal microflora in arbutin-induced cytotoxicity in HepG2 cell cultures.  

Science.gov (United States)

A possible role for metabolism by the human intestinal microflora in arbutin-induced cytotoxicity was investigated using human hepatoma HepG2 cells. When the cytotoxic effects of arbutin and hydroquinone (HQ), a deglycosylated metabolite of arbutin, were compared, HQ was more toxic than arbutin. Incubation of arbutin with a human fecal preparation could produce HQ. Following incubation of arbutin with a human fecal preparation for metabolic activation, the reaction mixture was filter-sterilized to test its toxic effects on HepG2 cells. The mixture induced cytotoxicity in HepG2 cells in a concentration-dependent manner. In addition, the mixture considerably inhibited expression of Bcl-2 together with an increase in Bax expression. Likewise, activation stimulated cleavage of caspase-3 and production of reactive oxygen species in HepG2 cell cultures. Furthermore, induction of apoptosis by the intestinal microflora reaction mixture was confirmed by the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick-end labeling assay. Taken together, these findings suggest that the human intestinal microflora is capable of metabolizing arbutin to HQ, which can induce apoptosis in mammalian cells. PMID:21889493

Khanal, Tilak; Kim, Hyung Gyun; Hwang, Yong Pil; Kong, Min Jeong; Kang, Mi Jeong; Yeo, Hee Kyung; Kim, Dong Hyun; Jeong, Tae Cheon; Jeong, Hye Gwang

2011-08-26

328

Glycyrrhizin stimulates growth of Eubacterium sp. strain GLH, a human intestinal anaerobe.  

UK PubMed Central (United Kingdom)

Eubacterium sp. strain GLH was isolated from human feces and produced two kinds of beta-D-glucuronidase (EC 3.2.1.31), one new enzyme specific for glycyrrhizin (GL) and the other for phenyl beta-D-glucuronides. GL or p-nitrophenyl-mono-beta-D-glucuronide (pNPG) stimulated the production of GL or pNPG beta-glucuronidases and the growth of strain GLH in a basal medium lacking carbohydrate. D-Glucuronic acid also stimulated the growth of the bacterium, but glycyrrhetic acid did not. The increase of GL beta-glucuronidase paralleled the growth of the Eubacterium strain in pure culture. These results suggest that glucuronides such as GL and pNPG stimulate the growth of the Eubacterium strain in a nutrient-poor medium by providing D-glucuronic acid through the activity of beta-glucuronidases. The increase in GL beta-glucuronidase activity in the presence of GL was observed during the cultivation of human intestinal flora in a general anaerobic medium. During mixed cultivation of the Eubacterium strain with Streptococcus faecalis, which does not produce GL beta-glucuronidase, GL beta-glucuronidase was also increased by GL or pNPG, but not by glycyrrhetic acid and p-nitrophenol. It is suggested that GL stimulates the growth of strain GLH even in the mixed culture.

Akao T; Akao T; Kobashi K

1988-08-01

329

Bacterial induction of inducible nitric oxide synthase in cultured human intestinal epithelial cells.  

UK PubMed Central (United Kingdom)

BACKGROUND & AIMS: Enterocytes play a major role in the mucosa as a source of proinflammatory cytokines and cytotoxins. We tested the hypothesis that bacteria induce expression of the inducible nitric oxide synthase (iNOS) in cultured human enterocytes. METHODS: DLD-1 and Caco-2BBe cell monolayers exposed to Salmonella dublin were analyzed for iNOS up-regulation and nitric oxide production (NOx) in the presence of various proinflammatory cytokines. RESULTS: S. dublin augmented NOx in interferon gamma (IFN-gamma)-primed cells but had no independent effect on iNOS expression. S. dublin-induced NOx was not mediated by endotoxin and was augmented by an enteroinvasive phenotype. In DLD-1 cells, S. dublin-mediated NOx was blocked by inhibitors of nuclear factor kappa B (NF-kappa B) and tyrosine kinase activation and was steroid resistant. Cis-acting elements in the human iNOS promoter responsive to endotoxin and S. dublin stimulation of IFN-gamma-treated DLD-1 cells were identified between 10.9 and 8.7 kilobases upstream of the transcription initiation site. CONCLUSIONS: S. dublin alters the regulation of iNOS messenger RNA in IFN-gamma-treated intestinal epithelial cells via a steroid-resistant pathway involving NF-kappa B and tyrosine kinase activity. Because bacterial interaction with cytokine-primed epithelial cells induces the synthesis of NO, an endogenous antimicrobial agent, these findings may have implications for the regulation of mucosal immunity.

Salzman AL; Eaves-Pyles T; Linn SC; Denenberg AG; Szabó C

1998-01-01

330

Study of the adhesion of Bifidobacterium bifidum MIMBb75 to human intestinal cell lines.  

Science.gov (United States)

The aim of this study was to investigate the adhesive phenotype of the human intestinal isolate Bifidobacterium bifidum MIMBb75 to human colon carcinoma cell lines. We have previously shown that the adhesion of this strain to Caco-2 cells is mediated by an abundant surface lipoprotein named BopA. In this study, we found that this strain adheres to Caco-2 and HT-29 cells, and that its adhesion strongly depends on the environmental conditions, including the presence of sugars and bile salts and the pH. Considerably more adhesion to a Caco-2 monolayer occurred in the presence of fucose and mannose and less when MIMBb75 grew in Oxgall bile salts compared to standard environmental conditions. In particular, growth in Oxgall bile salts reduced the adhesion ability of MIMBb75 and modified the SDS-PAGE profile of the cell wall associated proteins of the strain. The pH markedly affected both adhesion to Caco-2 and bacterial autoaggregation. Finally, experiments with sodium metaperiodate suggested that not only proteinaceous determinants are involved in the adhesion process of B. bifidum. In conclusion, it seems that the colonization strategy of this bacterium can be influenced by factors varying along the gastrointestinal tract, such as the presence of specific sugars and bile salts and the pH, possibly limiting the adhesion of B. bifidum to only restricted distal sites of the gut. PMID:19452211

Guglielmetti, Simone; Tamagnini, Isabella; Minuzzo, Mario; Arioli, Stefania; Parini, Carlo; Comelli, Elena; Mora, Diego

2009-05-19

331

Study of the adhesion of Bifidobacterium bifidum MIMBb75 to human intestinal cell lines.  

UK PubMed Central (United Kingdom)

The aim of this study was to investigate the adhesive phenotype of the human intestinal isolate Bifidobacterium bifidum MIMBb75 to human colon carcinoma cell lines. We have previously shown that the adhesion of this strain to Caco-2 cells is mediated by an abundant surface lipoprotein named BopA. In this study, we found that this strain adheres to Caco-2 and HT-29 cells, and that its adhesion strongly depends on the environmental conditions, including the presence of sugars and bile salts and the pH. Considerably more adhesion to a Caco-2 monolayer occurred in the presence of fucose and mannose and less when MIMBb75 grew in Oxgall bile salts compared to standard environmental conditions. In particular, growth in Oxgall bile salts reduced the adhesion ability of MIMBb75 and modified the SDS-PAGE profile of the cell wall associated proteins of the strain. The pH markedly affected both adhesion to Caco-2 and bacterial autoaggregation. Finally, experiments with sodium metaperiodate suggested that not only proteinaceous determinants are involved in the adhesion process of B. bifidum. In conclusion, it seems that the colonization strategy of this bacterium can be influenced by factors varying along the gastrointestinal tract, such as the presence of specific sugars and bile salts and the pH, possibly limiting the adhesion of B. bifidum to only restricted distal sites of the gut.

Guglielmetti S; Tamagnini I; Minuzzo M; Arioli S; Parini C; Comelli E; Mora D

2009-08-01

332

Digoxin inhibition of relaxation induced by prostacyclin and vasoactive intestinal polypeptide in small human placental arteries  

DEFF Research Database (Denmark)

Small chorionic plate arteries were obtained from human placentae following normal vaginal delivery. Tubal vascular preparations were dissected, mounted in organ baths, and their isometric tension was recorded. Digoxin (10(-6) M) caused a rise in basic tension, reaching a maximum of 17 per cent of contractions induced by potassium (124 mM) depolarization. Pretreatment with digoxin did not significantly influence the concentration-dependent contractile responses to 5-hydroxytryptamine and prostaglandin F2 alpha (PGF2 alpha). In preparations contracted with PGF2 alpha, cumulative addition of prostacyclin (PGI2) and vasoactive intestinal polypeptide (VIP) produced concentration dependent relaxations. Digoxin (10(-8) to 10(-6) M) inhibited and finally abolished these relaxant effects of PGI2 and VIP in a concentration-dependent fashion. Pretreatment by digoxin (10(-8) to 10(-6) M) diminished the relaxant effect of sodium nitroprusside, but the effect was less pronounced than that on PGI2- and VIP-induced relaxation. As PGI2 and VIP may be of importance for the maintenance of a low resistance of the fetal placental vascular bed, the finding that digoxin decreases the vasodilating effects of these agents might imply effects on placental resistance of cardiac glycosides when used in late human pregnancy.

Maigaard, S; Forman, Axel

1985-01-01

333

Effect of the artificial sweetener, sucralose, on small intestinal glucose absorption in healthy human subjects.  

UK PubMed Central (United Kingdom)

It has been reported that the artificial sweetener, sucralose, stimulates glucose absorption in rodents by enhancing apical availability of the transporter GLUT2. We evaluated whether exposure of the proximal small intestine to sucralose affects glucose absorption and/or the glycaemic response to an intraduodenal (ID) glucose infusion in healthy human subjects. Ten healthy subjects were studied on two separate occasions in a single-blind, randomised order. Each subject received an ID infusion of sucralose (4 mM in 0.9% saline) or control (0.9% saline) at 4 ml/min for 150 min (T = - 30 to 120 min). After 30 min (T = 0), glucose (25 %) and its non-metabolised analogue, 3-O-methylglucose (3-OMG; 2.5 %), were co-infused intraduodenally (T = 0-120 min; 4.2 kJ/min (1 kcal/min)). Blood was sampled at frequent intervals. Blood glucose, plasma glucagon-like peptide-1 (GLP-1) and serum 3-OMG concentrations increased during ID glucose/3-OMG infusion (P < 0.005 for each). However, there were no differences in blood glucose, plasma GLP-1 or serum 3-OMG concentrations between sucralose and control infusions. In conclusion, sucralose does not appear to modify the rate of glucose absorption or the glycaemic or incretin response to ID glucose infusion when given acutely in healthy human subjects.

Ma J; Chang J; Checklin HL; Young RL; Jones KL; Horowitz M; Rayner CK

2010-09-01

334

Challenges of Culturing Human Norovirus in Three-Dimensional Organoid Intestinal Cell Culture Models  

Science.gov (United States)

Human noroviruses are the most common cause of acute gastroenteritis worldwide. Recently, cell culture systems have been described using either human embryonic intestinal epithelial cells (Int-407) or human epithelial colorectal adenocarcinoma cells (Caco-2) growing on collagen-I porous micro carrier beads in a rotating bioreactor under conditions of physiological fluid shear. Here, we describe the efforts from two independent laboratories to implement this three dimensional (3D) cell culture system for the replication of norovirus. Int-407 and Caco-2 were grown in a rotating bioreactor for up to 28 days. Prior to infection, cells were screened for the presence of microvilli by electron microscopy and stained for junction proteins (zonula occludens-1, claudin-1, and ?-catenin). Differentiated 3D cells were transferred to 24-well plates and infected with bacteria-free filtrates of various norovirus genotypes (GI.1, GI.3, GI.8, GII.2, GII.4, GII.7, and GII.8). At 12 h, 24 h, and 48 h post inoculation, viral RNA from both cells and supernatants were collected and analyzed for norovirus RNA by real-time reverse transcription PCR. Despite observations of high expression of junction proteins and microvilli development in stained thin sections, our data suggest no significant increase in viral titer based on norovirus RNA copy number during the first 48 h after inoculation for the different samples and virus culture conditions tested. Our combined efforts demonstrate that 3D cell culture models using Int-407 or Caco-2 cells do not support norovirus replication and highlight the complexity and difficulty of developing a reproducible in vitro cell culture system for human norovirus.

Papafragkou, Efstathia; Hewitt, Joanne; Park, Geun Woo; Greening, Gail; Vinje, Jan

2013-01-01

335

Challenges of culturing human norovirus in three-dimensional organoid intestinal cell culture models.  

UK PubMed Central (United Kingdom)

Human noroviruses are the most common cause of acute gastroenteritis worldwide. Recently, cell culture systems have been described using either human embryonic intestinal epithelial cells (Int-407) or human epithelial colorectal adenocarcinoma cells (Caco-2) growing on collagen-I porous micro carrier beads in a rotating bioreactor under conditions of physiological fluid shear. Here, we describe the efforts from two independent laboratories to implement this three dimensional (3D) cell culture system for the replication of norovirus. Int-407 and Caco-2 were grown in a rotating bioreactor for up to 28 days. Prior to infection, cells were screened for the presence of microvilli by electron microscopy and stained for junction proteins (zonula occludens-1, claudin-1, and ?-catenin). Differentiated 3D cells were transferred to 24-well plates and infected with bacteria-free filtrates of various norovirus genotypes (GI.1, GI.3, GI.8, GII.2, GII.4, GII.7, and GII.8). At 12 h, 24 h, and 48 h post inoculation, viral RNA from both cells and supernatants were collected and analyzed for norovirus RNA by real-time reverse transcription PCR. Despite observations of high expression of junction proteins and microvilli development in stained thin sections, our data suggest no significant increase in viral titer based on norovirus RNA copy number during the first 48 h after inoculation for the different samples and virus culture conditions tested. Our combined efforts demonstrate that 3D cell culture models using Int-407 or Caco-2 cells do not support norovirus replication and highlight the complexity and difficulty of developing a reproducible in vitro cell culture system for human norovirus.

Papafragkou E; Hewitt J; Park GW; Greening G; Vinjé J

2013-01-01

336

Challenges of culturing human norovirus in three-dimensional organoid intestinal cell culture models.  

Science.gov (United States)

Human noroviruses are the most common cause of acute gastroenteritis worldwide. Recently, cell culture systems have been described using either human embryonic intestinal epithelial cells (Int-407) or human epithelial colorectal adenocarcinoma cells (Caco-2) growing on collagen-I porous micro carrier beads in a rotating bioreactor under conditions of physiological fluid shear. Here, we describe the efforts from two independent laboratories to implement this three dimensional (3D) cell culture system for the replication of norovirus. Int-407 and Caco-2 were grown in a rotating bioreactor for up to 28 days. Prior to infection, cells were screened for the presence of microvilli by electron microscopy and stained for junction proteins (zonula occludens-1, claudin-1, and ?-catenin). Differentiated 3D cells were transferred to 24-well plates and infected with bacteria-free filtrates of various norovirus genotypes (GI.1, GI.3, GI.8, GII.2, GII.4, GII.7, and GII.8). At 12 h, 24 h, and 48 h post inoculation, viral RNA from both cells and supernatants were collected and analyzed for norovirus RNA by real-time reverse transcription PCR. Despite observations of high expression of junction proteins and microvilli development in stained thin sections, our data suggest no significant increase in viral titer based on norovirus RNA copy number during the first 48 h after inoculation for the different samples and virus culture conditions tested. Our combined efforts demonstrate that 3D cell culture models using Int-407 or Caco-2 cells do not support norovirus replication and highlight the complexity and difficulty of developing a reproducible in vitro cell culture system for human norovirus. PMID:23755105

Papafragkou, Efstathia; Hewitt, Joanne; Park, Geun Woo; Greening, Gail; Vinjé, Jan

2013-06-03

337

Microlipid-induced oxidative stress in human breastmilk: in vitro effects on intestinal epithelial cells.  

UK PubMed Central (United Kingdom)

OBJECTIVES: To (1) determine whether medium chain fatty acids (Microlipid) added to human breastmilk generates reactive oxygen species (ROS), and (2) measure the physiological effect(s) of Microlipid) (ML)-supplemented human breastmilk in an enterocyte cell culture bioassay. METHODS: ML was added to milk according to manufacturer's recommendations and total hydroperoxides measured at intervals with the FOX 2 and TBARS assays. Physiological effects of supplementation were measured using a human enterocyte cell line (Caco-2BBE) and/or a primary human fetal intestinal cell culture (FHS-74 Int). Endpoints included: intracellular oxidative stress, transepithelial electrical resistance (TEER), apoptosis, and interleukin (IL)-6 production. RESULTS: Immediately postsupplementation, ML did not significantly increase ROS, as determined by both the FOX 2 and TBARS assays. Further, storage of milk + ML at 4 degrees C prevented significant increases in total hydroperoxides. However, by 4 hours postsupplementation at room temperature, both assays revealed significantly higher hydroperoxide and lipid peroxide levels. ML-supplemented milk stored at room temperature for 4 hours had the following effects in cell culture bioassays: elevated oxidative stress, increased rates of apoptosis, decreased transmembrane electrical resistance (TEER) values and, in both cell culture assays, significantly increased secretion of IL-6. CONCLUSIONS: Based on our measurements of extracellular and intracellular ROS, milk supplemented with fresh ML does not induce significant oxidative stress. However, when stored for 4 hours at room temperature, ML induces significant levels of oxidative stress. Decreases in TEER and increases in apoptosis and IL-6 secretion are consistent with ML-induced oxidative stress. It therefore is likely that in clinical situations, if ML-supplemented milk is not administered quickly, the newborn may be placed at greater risk of oxidative stress.

Diehl-Jones WL; Askin DF; Friel JK

2007-12-01

338

Correlation between human papillomavirus infection and bladder transitional cell carcinoma  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background To determine the association of human papillomavirus infection (HPV) and transitional cell carcinoma (TCC). Methods Using polymerase chain reaction, fifty-nine bladder tissue specimens of patients with transitional cell carcinoma of bladder compared with 20 bladder samples of cases with non-neoplastic disorders. Results Male to female ratio was similar in the two groups (50/9 vs. 16/4, P = 0.62). Mean age was 67 ± 10.8 years and 52 ± 20.3 years in the case and control groups, respectively (P = 0.6). Of the 59 tissue specimens with diagnosis of transitional cell carcinoma, HPV DNA was detected in 21 (35.6%) samples, while it was present in only one sample (5%) in the control group (P = 0.008). HPV18 was the most common type of virus with the incidence rate of 17/21(81%). Conclusion HPV might play a causative role in transitional cell carcinoma of bladder in our geographic area.

Barghi MR; Hajimohammadmehdiarbab A; Moghaddam SMM Hosseini; Kazemi B

2005-01-01

339

Assessment of the mode of action underlying development of rodent small intestinal tumors following oral exposure to hexavalent chromium and relevance to humans.  

Science.gov (United States)

Abstract Chronic exposure to high concentrations of hexavalent chromium (Cr(VI)) in drinking water causes intestinal adenomas and carcinomas in mice, but not in rats. Cr(VI) causes damage to intestinal villi and crypt hyperplasia in mice after only one week of exposure. After two years of exposure, intestinal damage and crypt hyperplasia are evident in mice (but not rats), as are intestinal tumors. Although Cr(VI) has genotoxic properties, these findings suggest that intestinal tumors in mice arise as a result of chronic mucosal injury. To better understand the mode of action (MOA) of Cr(VI) in the intestine, a 90-day drinking water study was conducted to collect histological, biochemical, toxicogenomic and pharmacokinetic data in intestinal tissues. Using MOA analyses and human relevance frameworks proposed by national and international regulatory agencies, the weight of evidence supports a cytotoxic MOA with the following key events: (a) absorption of Cr(VI) from the intestinal lumen, (b) toxicity to intestinal villi, (c) crypt regenerative hyperplasia and (d) clonal expansion of mutations within the crypt stem cells, resulting in late onset tumorigenesis. This article summarizes the data supporting each key event in the MOA, as well as data that argue against a mutagenic MOA for Cr(VI)-induced intestinal tumors. PMID:23445218

Thompson, Chad M; Proctor, Deborah M; Suh, Mina; Haws, Laurie C; Kirman, Christopher R; Harris, Mark A

2013-03-01

340

Assessment of the mode of action underlying development of rodent small intestinal tumors following oral exposure to hexavalent chromium and relevance to humans.  

UK PubMed Central (United Kingdom)

Abstract Chronic exposure to high concentrations of hexavalent chromium (Cr(VI)) in drinking water causes intestinal adenomas and carcinomas in mice, but not in rats. Cr(VI) causes damage to intestinal villi and crypt hyperplasia in mice after only one week of exposure. After two years of exposure, intestinal damage and crypt hyperplasia are evident in mice (but not rats), as are intestinal tumors. Although Cr(VI) has genotoxic properties, these findings suggest that intestinal tumors in mice arise as a result of chronic mucosal injury. To better understand the mode of action (MOA) of Cr(VI) in the intestine, a 90-day drinking water study was conducted to collect histological, biochemical, toxicogenomic and pharmacokinetic data in intestinal tissues. Using MOA analyses and human relevance frameworks proposed by national and international regulatory agencies, the weight of evidence supports a cytotoxic MOA with the following key events: (a) absorption of Cr(VI) from the intestinal lumen, (b) toxicity to intestinal villi, (c) crypt regenerative hyperplasia and (d) clonal expansion of mutations within the crypt stem cells, resulting in late onset tumorigenesis. This article summarizes the data supporting each key event in the MOA, as well as data that argue against a mutagenic MOA for Cr(VI)-induced intestinal tumors.

Thompson CM; Proctor DM; Suh M; Haws LC; Kirman CR; Harris MA

2013-03-01

 
 
 
 
341

Selective antimicrobial modulation of the intestinal tract by norfloxacin in human volunteers and in gnotobiotic mice associated with a human fecal flora.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Intestinal endogenous members of the family Enterobacteriaceae were eliminated in 12 human volunteers treated with 400 or 800 mg of oral norfloxacin per day for 5 days. No clones resistant to quinolone derivatives were isolated. Counts of aerotolerant streptococci were affected to various degrees, d...

Pecquet, S; Andremont, A; Tancrède, C

342

Human factors issues for resolving adverse effects of human work underload and workload transitions in complex human-machine systems  

Energy Technology Data Exchange (ETDEWEB)

A workshop was conducted whose specific purpose was to build on earlier work of the United States National Research Council, United States Federal government agencies, and the larger human factors community to: (1) clarify human factors issues pertaining to degraded performance in advanced human-machine systems (e.g., nuclear production, transportation, aerospace) due to human work underload and workload transition, and (2) develop strategies for resolving these issues. Recent history demonstrates that: (1) humans often react adversely to their diminishing roles in advanced human-machine systems, and therefore (2) new allocation models and strategies are required if humans are to be willing and able to assume diminishing and shifting roles assigned to them in these systems, and are to accept new technologies making up these systems. Problems associated with theses diminishing and shifting human roles are characterized as work underload and workload transitions. The workshop affirmed that: (1) work underload and workload transition are issues that will have to be addressed by designers of advanced human-machine systems, especially those relying on automation, if cost, performance, safety, and operator acceptability are to be optimized, (2) human machine allocation models, standards, and guidelines which go beyond simple capability approaches will be needed to preclude or seriously diminish the work underload and workload transition problems, and (3) the 16 workload definition, measurement, situational awareness, and trust issues identified during the workshop, need resolution if these models, standards, and guidelines are to be achieved.

Ryan, T.G.

1995-10-01

343

Specific binding of lactoferrin to Escherichia coli isolated from human intestinal infections  

Energy Technology Data Exchange (ETDEWEB)

The degrees of human lactoferrin (HLf) and bovine lactoferrin (BLf) binding in 169 Escherichia coli strains isolated from human intestinal infections, and in an additional 68 strains isolated from healthy individuals, were examined in a {sup 125}I-labelled protein binding assay. The binding was expressed as a percentage calculated from the total labelled ligand added to bacteria. The HLf and BLf binding to E. coli was in the range 3.7 to 73.4% and 4.8 to 61.6%, respectively. Enterotoxigenic strains demonstrated a significantly higher HLf binding (median = 19%) than enteropathogenic, enteroinvasive, enterohaemorrhagic strains or normal intestinal E. coli isolates (medians 6 to 9). Enteropathogenic strains belonging to serotypes O44 and O127 demonstrated significantly higher HLf binding compared to O26, O55, O111, O119 and O126. No significant differences in the degree of HLf or BLf binding were found between aerobactin-producing and non-producing strains. The interaction was further characterized in a high Lf-binging EPEC strain, E34663 (serotype O127). The binding was stable in the pH range 4.0 to 7.5, did not dissociate in the presence of 2M NaCl or 2M urea, and reached saturation within two h. Unlabelled HLf and BLf displaced the {sup 125}I-HLf binding to E34663 in a dose-dependent manner. Apo- and iron-saturated forms of Lf demonstrated similar binding to E34663. Among various unlabelled subephithelial matrix proteins and carbohydrates tested (in 10{sup 4}-fold excess) only fibronectin and fibrinogen caused a moderate inhibition of {sup 125}I-HLf binding. According to Scatchard plot analysis, 5,400 HLf-binding sites/cell, with an affinity constant (K{sub a}) of 1.4 x 10{sup -7} M, were estimated in strain E34663. These data establish the presence of a specific Lf-binding mechanism in E. coli. (au).

Naidu, S.S.; Erdei, J.; Forsgren, A.; Naidu, A.S. (Departments of Medical Microbiology, Malmoe General Hospital (Sweden)); Czirok, E.; Gado, I. (National Institute of Hygiene, Budapest (Hungary)); Kalfas, S. (School of Dentistry, University of Lund, Malmoe (Sweden)); Thoren, A. (Infectious Diseases, Malmoe General Hospital (Sweden))

1991-01-01