The pH dependence of the hemolytic potency of bile salts

Ilani, Asher; Granoth, Ruth

doi:10.1016/0005-2736(90)90085-3

Cited by 26 publications

(15 citation statements)

References 17 publications

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“…Variations of environment pH involves all the main structural and functional RBCs links and may result in oxidative damage of cell membrane leading to hemolysis. The principal functions of RBCs are recognised to be the transport of oxygen and CO 2 , as well as the binding of acids and alkali, formed in tissues by metabolism, and their acidification can result in an elevation of potential endogenous cytotoxic metabolites [30]. Acidosis leads also to a release of metals with variable valency from metalloproteins, which participate in Fenton and Haber-Weiss reactions, stimulating OH˙ and oxidant formation [31] that can result in oxidative damage to cell membranes and hemolysis [32].…”

Section: Discussionmentioning

confidence: 99%

Study of Incubation Conditions for Erythrocytes Osmotic Fragility Testing in Dromedary Camel (Camelus dromedarius)

Islah¹,

Bargaa²,

Youssef³

et al. 2016

International Journal of Research in Environmental Science

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Section: Discussionmentioning

confidence: 99%

Study of Incubation Conditions for Erythrocytes Osmotic Fragility Testing in Dromedary Camel (Camelus dromedarius)

Islah¹,

Bargaa²,

Youssef³

et al. 2016

International Journal of Research in Environmental Science

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“…Toxicity and haemolytic effects remained high in the solution supplemented with 5 mmol l −1 DCA (Table 6). Although ionization of DCA causes a reduction of the HI‐index from 1·46 to 0·72, the hydrophobicity remains high and the membrane damaging effect is still responsible for the significant die‐off at a concentration of 5 mmol l −1 DCA (Ilani & Granoth 1990).…”

Section: Discussionmentioning

confidence: 99%

Bile salt deconjugation by Lactobacillus plantarum 80 and its implication for bacterial toxicity

Boever

Verstraete

1999

J Appl Microbiol

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. 1999. The effects of bile salts on the survival of lactobacilli were investigated using glycocholic acid, cholic acid and deoxycholic acid as model compounds and the bile salt hydrolase active Lactobacillus plantarum 80 (BSH + ) and its BSH negative mutant. The detrimental effects of cholic acid, i.e. growth inhibition and cytotoxicity at a concentration of 1 and 5 mmol l , respectively, were considered to be due to the hydrophobic protonated form of the molecule, which brings about membrane damage. The conversion of glycocholic acid to cholic acid by the BSH active L. plantarum 80 caused a growth inhibition which was comparable with the inhibition observed in the broth supplemented with 1 mmol l −1 cholic acid. Deoxycholic acid caused toxicity through membrane damage when the compound was in solution. Its toxicity disappeared in the culture broth as the molecule precipitated. In case of cholic acid, the toxicity could be removed by buffering the solution at pH 7·0. It was calculated that at this pH most of the cholic acid molecules were ionized. The results led to the formulation of an extended hypothesis about the ecological significance of bile salt transformations. Primary deconjugation is carried out to counteract intracellular acidification. Yet, the deconjugated molecule can be harmful at moderately acidic pH-values. In this case, the BSH + strains could effectively profit from their activity in case they are associated with 7a-dehydroxylating bacteria which dehydroxylate the deconjugated bile salts. The dehydroxylated molecule has a low solubility and precipitates at moderately acidic pH.

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“…The calculated median concentrations of protonated DCA did indeed show higher concentrations after a right hemicolectomy. In particular, the undissociated secondary bile acids are thought to cause cellular damage [23] and to stimulate the development of carcinomas. Therefore, one would expect the intraluminal contents of the remaining colon after right hemicolectomy to be more cytotoxic than after left hemicolectomy.…”

Section: Discussionmentioning

confidence: 99%

Effects of hemicolectomy on bile acid metabolism in relation to colon carcinogenesis in man

Gorkom

Cats

Meer

et al. 1997

Eur J Clin Investigation

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Bile acids are probably important in colon carcinogenesis. Regional differences in bile acid metabolism within the colon were studied to illuminate the preferential distal occurrence of colon cancer in Western countries. Faeces (24 h) were collected for bile acid measurement from 25 patients with hemicolectomy (nine left and 16 right) and 17 adenoma patients with an intact colon (control subjects). Duodenal bile and cytolytic and alkaline phosphatase activity of faecal water were also studied. The median percentage of deoxycholic acid (DCA) was lower in the hemicolectomy groups [left 48% (range 38-57%), right 45% (2-62%) vs. control subjects 59% (38-70%), P < 0.05]. In duodenal bile, the proportion of DCA in left [4% (1-25%)] was lower than in the patients with right hemicolectomy [19% (0-69%)] and control subjects [24% (7-50%)] P < 0.05. Faecal concentration of protonated DCA was higher in those with right hemicolectomy (0.101 mumol g-1) than in those with left hemicolectomy (0.048 mol g-1), which coincided with a higher cytolytic [right 49% (3-93%), left 2% (1-37%)] and alkaline phosphatase activity [right 6.7 U mL-1 (1.2-40.1 U mL-1), left (2.0 U mL-1 (1-25.7 U mL-1), both P < 0.02]. These findings suggest differences in bile acid metabolism between the proximal and distal colon that may contribute to the disparity in cancer risk.

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The pH dependence of the hemolytic potency of bile salts

Cited by 26 publications

References 17 publications

Study of Incubation Conditions for Erythrocytes Osmotic Fragility Testing in Dromedary Camel (Camelus dromedarius)

Study of Incubation Conditions for Erythrocytes Osmotic Fragility Testing in Dromedary Camel (Camelus dromedarius)

Bile salt deconjugation by Lactobacillus plantarum 80 and its implication for bacterial toxicity

Effects of hemicolectomy on bile acid metabolism in relation to colon carcinogenesis in man

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