Gastrointestinal intraluminal pH in normal subjects and those with colorectal adenoma or carcinoma.

Pye, Geoffrey W.; Evans, D. F.; Ledingham, S; Hardcastle, J. D.

doi:10.1136/gut.31.12.1355

Cited by 57 publications

(30 citation statements)

References 14 publications

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“…The median pH value was 6.2. This is in agreement with median fasting duodenal pH values reported in the literature, which vary from 5.95 to 6.72 (10Y13, 15,50,51). pH of duodenal aspirates drifted to higher values, increasing by up to 6% within 20 min at room temperature.…”

Section: Fasted Duodenumsupporting

confidence: 93%

Characterization of the Human Upper Gastrointestinal Contents Under Conditions Simulating Bioavailability/Bioequivalence Studies

et al. 2006

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Section: Fasted Duodenumsupporting

confidence: 93%

Characterization of the Human Upper Gastrointestinal Contents Under Conditions Simulating Bioavailability/Bioequivalence Studies

et al. 2006

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“…8 The reduction in pH associated with the production of SCFAs has been proposed as a protective factor5 as a higher faecal pH has been noted in high risk populations.20 Some studies have shown high faecal pH in persons with colonic cancer,2' although others have failed to confirm these findings. 22 We detected no differences in faecal pH in our three subject groups suggesting that neither the FAP gene nor the presence of polyps influences faecal pH.…”

Section: Discussionmentioning

confidence: 52%

Colonic fermentation of complex carbohydrates in patients with familial adenomatous polyposis.

Bradburn

Mathers

Gunn

et al. 1993

Gut

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Decreased production of butyric acid by colonic carbohydrate fermentation may predispose to colonic carcinogenesis, with the implicit assumption that the decrease in faecal butyrate found predates the development ofthe tumour. The influence of the genetic predisposition to colonic tumours and the presence of colonic polyps on in vitro fermentation of carbohydrates was examined. Stool samples from 11 normal controls and 20 patients with familial adenomatous polyposis (FAP) were incubated anaerobically with a range of carbohydrates. Fermentation patterns were similar for glucose and raffinose. These sugars produced different short chain fatty acid (SCFA) patterns from the two polysaccharides, starch and arabinogalactan, which differed one from the other. The FAP gene carriers with polyps produced less butyrate than normal controls (p<0005) and gene carriers without polyps (p<0 05). There were corresponding decreases in the molar ratios of butyrate. Gene carriers without polyps produced less absolute amounts of acetate than normal controls (p<0.05) and slightly less total SCFAs (p<0 05) but were otherwise not significantly different. The decreased production of butyrate noted by other workers may be secondary to the tumours rather than a contributory cause.

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“…The normal pH in the vagina is pH 4, but after the deposition of semen, it may reach pH 8. The normal rectal pH range in adult males is between pH 6 and 7 but has been shown to be as high as pH 8 (14,21,25,31). Ideally, a topical microbicide must thus retain its activity over a broad range of pH values.…”

Section: Discussionmentioning

confidence: 99%

In Vitro Microbicidal Activities of Cecropin Peptides D2A21 and D4E1 and Gel Formulations Containing 0.1 to 2% D2A21 against Chlamydia trachomatis

Ballweber¹,

Jaynes²,

Stamm

et al. 2002

Antimicrob Agents Chemother

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Topically applied microbicides that eradicate pathogens at the time of initial exposure represent a powerful strategy for the prevention of sexually transmitted infections. To aid in the further development of an effective topical microbicide, we assessed the minimum cidal concentration (MCC) of two cecropin peptides, D2A21 and D4E1, and gel formulations containing 0.1 to 2% D2A21 against Chlamydia trachomatis in vitro. The MCC of peptide D2A21was 5 M (18.32 g/ml), and that of peptide D4E1 was 7.5 M (21.69 g/ml). The MCC of gel formulations containing 2% D2A21 was 0.2 mM (0.7 mg/ml), and that of gel formulations containing 0.5% D2A21 was 0.2 mM (0.7 mg/ml). There was no significant variation in the results when two different C. trachomatis strains were tested, and the addition of 10% human blood did not significantly alter the MCCs. pH values above and below 7 reduced the activity of the D2A21 peptide alone, but the MCC of the 2% D2A21 gel formulation was only slightly altered at the various pHs tested. Ultrastructural studies indicated that C. trachomatis membranes were disrupted after D2A21 exposure, resulting in leakage of the cytoplasmic contents. These in vitro results suggest that these cecropin peptides may be an effective topical microbicide against C. trachomatis and support the need for further evaluation.

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Gastrointestinal intraluminal pH in normal subjects and those with colorectal adenoma or carcinoma.

Cited by 57 publications

References 14 publications

Characterization of the Human Upper Gastrointestinal Contents Under Conditions Simulating Bioavailability/Bioequivalence Studies

Characterization of the Human Upper Gastrointestinal Contents Under Conditions Simulating Bioavailability/Bioequivalence Studies

Colonic fermentation of complex carbohydrates in patients with familial adenomatous polyposis.

In Vitro Microbicidal Activities of Cecropin Peptides D2A21 and D4E1 and Gel Formulations Containing 0.1 to 2% D2A21 against Chlamydia trachomatis

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