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Introducción: los ácidos biliares no solo tienen como actividad biológica regular la absorción de vitaminas liposolubles, colesterol y lípidos, sino actúan también como moléculas de señalización, moduladores de la proliferación celular intestinal, de la expresión de genes y del metabolismo energético según estudios in vitro e in vivo; en condiciones fisiológicas mantienen su homeostasis, que al ser interrumpida promueve suacción toxicológica. Objetivo: describir la actualidad de los nuevos conocimientos sobre la actividad biológica y toxicológica de los ácidos biliares en el aparato digestivo, dirigido a cirujanos generales, gastroenterólogos, clínicos y fisiólogos que les permitan contextualizar el proceso inflamación-carcinogénesis relacionado con los efectos toxicológicos de los ácidos biliares. Método: se realizó una revisión sistemática de la actividad biológica y toxicológica de los ácidos biliares para los cirujanos generales, gastroenterólogos, clínicos y fisiólogos, como herramienta útil en la compresión fisiopatológico del metabolismo de los ácidos biliares. Conclusión: los ácidos biliares desempeñan una función clave como moléculas de señalización en la modulación de la proliferación de células epiteliales, la expresión de genes y el metabolismo energético, que cuando se interrumpe su homeostasis se promueve la acción tóxica de estos, lo que se traduce en el proceso inflamación-carcinogénesis digestiva(AU)

Introduction: bile acids not only have as a regular biological activity the absorption of fat-soluble vitamins, cholesterol and lipids, but also act as signaling molecules, modulators of intestinal cell proliferation, gene expression and energy metabolism according to in vitro studies and in vivo; under physiological conditions they maintain their homeostasis, which when interrupted promotes their toxicological action. Objective: to describe the news of the new knowledge about the biological and toxicological activity of bile acids in the digestive system, aimed at general surgeons, gastroenterologists, clinicians and physiologists that allow them to contextualize the inflammation-carcinogenesis process related to the toxicological effects of bile acids. Method: A systematic review of the biological and toxicological activity of bile acids was performed for general surgeons, gastroenterologists, clinicians and physiologists, as a useful tool in the pathophysiological compression of bile acid metabolism. Conclusion: bile acids play a key role as signaling molecules in the modulation of epithelial cell proliferation, gene expression and energy metabolism, which when their homeostasis is interrupted, their toxic action is promoted, which translates in the inflammation-digestive carcinogenesis process(AU)

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Background: Multiple resistances to antibiotics are an emergent problem worldwide. Scientists intensively search for new substances with the antimicrobial potential or the mode to restore the activity of old-generation antibiotics. Ampicillin is the antibiotic with the expanded range of antimicrobial activity, but its use has decreased due to the poor absorption and highly developed resistance. In vivo studies showed that ampicillin has better absorption and bioavailability if combined with bile acid salts. The aim of this study was to examine antimicrobial effects of ampicillin alone and its combination with semisynthetic monoketocholic acid salt (MKH) in vitro.Materials, Methods & Results: In this study, commercial preparation of ampicillin and sodium salt of 3,7-dihydroxy-12- oxo-5-cholanate were used. Their effects were evaluated on Escherichia coli (E. coli), Enterococcus faecalis (E. faecalis) and Enterococcusfaecium (E. faecium), obtained from urine specimens of dogs with clinically manifested cystitis. The first two investigated strains were ampicillin-sensitive, while E. faecium was resistant to ampicillin. Modified macrodilution method according to Clinical and Laboratory Standards Institute Guidelines (M7-A8) was performed. Bacterial suspension equivalent to 0.5 McFarland was prepared in saline, compared to the standard (Biomerieux) ad oculi. The density was [...](AU)

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Background: Multiple resistances to antibiotics are an emergent problem worldwide. Scientists intensively search for new substances with the antimicrobial potential or the mode to restore the activity of old-generation antibiotics. Ampicillin is the antibiotic with the expanded range of antimicrobial activity, but its use has decreased due to the poor absorption and highly developed resistance. In vivo studies showed that ampicillin has better absorption and bioavailability if combined with bile acid salts. The aim of this study was to examine antimicrobial effects of ampicillin alone and its combination with semisynthetic monoketocholic acid salt (MKH) in vitro.Materials, Methods & Results: In this study, commercial preparation of ampicillin and sodium salt of 3,7-dihydroxy-12- oxo-5-cholanate were used. Their effects were evaluated on Escherichia coli (E. coli), Enterococcus faecalis (E. faecalis) and Enterococcusfaecium (E. faecium), obtained from urine specimens of dogs with clinically manifested cystitis. The first two investigated strains were ampicillin-sensitive, while E. faecium was resistant to ampicillin. Modified macrodilution method according to Clinical and Laboratory Standards Institute Guidelines (M7-A8) was performed. Bacterial suspension equivalent to 0.5 McFarland was prepared in saline, compared to the standard (Biomerieux) ad oculi. The density was [...]

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Background: Metabolic capacity of gut microflora is huge and this “microb” organ can be considered as second biggestmetabolic organ in body. The potential for an antibiotic to influence gut microflora is related to its spectrum of activity,pharmacokinetics, dosage and length of administration. In terms of pharmacokinetics, the rate of intestinal absorption playsa fundamental role. Apart from basic physiological functions, bile acids and their analogues are recognized as transportpromoters for other substances, in potentiating their action. The aim of this study was to demonstrate potential protectiveeffect of monoketocholic bile acid on rat intestinal microflora from oral ampicillin.Materials, Methods & Results: Eighteen Wistar rats were divided into three groups (n = 6). The experimental protocol wasapproved by Ethics Committee on Animal Use of the University Novi Sad. All animals received 10 mL/kg of body weightof drugs solutions per os by oral intubations. The animals have been treated twice daily for three days, with saline, ampicillin 500 mg/kg and ampicillin 500 mg/kg + monoketocholic bile acid (MKH) 4 mg/kg. The fecal pellets were collectedtwice, before and after the treatment was completed. Within 2 h of collection, samples of whole pellets were processedmicrobiologically. Weighed portions of feces were suspended 1:10 in sterile 0.9% NaCl and further diluted with samesolutions up to 1: 1013. The number of colony forming units (CFU) was determined by direct counting. Only the platescontaining 30 to 300 CFU were considered as valid. The ampicillin treated group, showed significant reduction...(AU)

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Background: Metabolic capacity of gut microflora is huge and this “microb” organ can be considered as second biggestmetabolic organ in body. The potential for an antibiotic to influence gut microflora is related to its spectrum of activity,pharmacokinetics, dosage and length of administration. In terms of pharmacokinetics, the rate of intestinal absorption playsa fundamental role. Apart from basic physiological functions, bile acids and their analogues are recognized as transportpromoters for other substances, in potentiating their action. The aim of this study was to demonstrate potential protectiveeffect of monoketocholic bile acid on rat intestinal microflora from oral ampicillin.Materials, Methods & Results: Eighteen Wistar rats were divided into three groups (n = 6). The experimental protocol wasapproved by Ethics Committee on Animal Use of the University Novi Sad. All animals received 10 mL/kg of body weightof drugs solutions per os by oral intubations. The animals have been treated twice daily for three days, with saline, ampicillin 500 mg/kg and ampicillin 500 mg/kg + monoketocholic bile acid (MKH) 4 mg/kg. The fecal pellets were collectedtwice, before and after the treatment was completed. Within 2 h of collection, samples of whole pellets were processedmicrobiologically. Weighed portions of feces were suspended 1:10 in sterile 0.9% NaCl and further diluted with samesolutions up to 1: 1013. The number of colony forming units (CFU) was determined by direct counting. Only the platescontaining 30 to 300 CFU were considered as valid. The ampicillin treated group, showed significant reduction...

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Hamsters were fed for 4 weeks on four different diets: control (C) (balanced diet containing 20 % corn oil as the lipid source), hypercholesterolemic (H) (identical to C but containing 12 % coconut oil, 8 % corn oil and 0.1 % cholesterol as the lipid source), amaranth oil (A) (identical to H without corn oil but with amaranth oil), and squalene (S) (identical to H but admixed with squalene in the ratio found in amaranth oil). There were no significant differences in lipid profile, and in the cholesterol excreted in the animals' feces from amaranth oil (A) and squalene (S) groups. Fecal excretion of bile acids was greater in the amaranth oil (A) and squalene groups (S) as compared to the other groups. The scores of steatosis and parenchymal inflammation observed in the amaranth oil (A) and squalene groups (S) were superior to the ones observed in the other groups. Our findings demonstrated that amaranth oil, and its component squalene, increased the excretion of bile acids but did not have a hypocholesterolemic effect in hamsters fed on a diet containing high amounts of saturated fat and cholesterol.

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The simple and low cost ß-cyclodextrin (ß-CD)-phenolphthalein (PHP) inclusion complex was used for both the study of physical-chemical parameters and validation of analytical procedures for deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA) determinations in different formulations. The usefulness of this inclusion complex is proposed either in the form of kit reagent and as an original optical sensor for DCA and UDCA. The results showed that temperature had a negative effect on the equilibrium constant resulting in high negative values of enthalpy and positive values of entropy. The half-life values for DCA and UDCA measurements were 68.71 and 294.71 days, respectively. The method was validated showing limits of detection and quantification of 4.92×10(-5) mol L(-1) and 1.64×10(-4) mol L(-1) for DCA, 1.14×10(-5) mol L(-1) and 3.79×10(-5) mol L(-1) for UDCA, respectively. The developed optical sensor also showed response linearity, ease of implementation and potential application in fast screening tasks even out of the laboratory.

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A considerable amount of attention has been focused on the use of lactobacilli as probiotics. The use of microorganisms as probiotics must meet certain criteria, among these; the resistance to low pH and bile salts is of great importance. Different procedures have been designed to evaluate tolerance to gastrointestinal transit. Since resistance to low pH and bile salts is critical in the evaluation of probiotic strains, the aim of this study was to compare resistance to bile salts for 20 strains of porcine Lactobacillus reuteri that had been isolated from healthy pigs, using two different procedures based on exposure to low pH. Statistical analysis revealed no difference in resistance of the strains to bile salts whether pH was low or not. The use of low pH prior to exposure to bile salts therefore more closely represents physiological conditions that should be used for the evaluation of potential porcine probiotic lactobacilli. Further studies using digestive enzymes are required to evaluate resistance to gastrointestinal transit, since it is an important factor in the evaluation of strains with potential probiotic activity.

Existe un interés creciente en el uso de lactobacilos como probióticos. El uso de microorganismos como probióticos, requiere que éstos cubran ciertos requisitos, dentro de los cuales la resistencia a pH ácido y a sales biliares, se consideran de suma importancia. Actualmente existen distintos procedimientos que permiten evaluar la tolerancia al tránsito gastrointestinal. Debido a que la resistencia a pH ácido y a sales biliares es una condición crítica dentro de la evaluación de cepas probióticas, la finalidad del presente trabajo consistió en comparar la resistencia a sales biliares de 20 cepas de Lactobacillus reuteri aisladas de cerdos sanos, mediante dos procedimientos diferentes basados en la exposición a pH ácido. El análisis estadístico no mostró diferencias en la resistencia de las cepas a sales biliares cuando se realizó una exposición previa a pH ácido. Así, la exposición a pH ácido previo a la incubación con sales biliares, asemeja más a las condiciones fisiológicas que el microorganismo encontrará de manera natural y es una buena alternativa en la evaluación probiótica de lactobacilos de origen porcino. Se requieren estudios que incluyan enzimas digestivas, con el fin de evaluar la resistencia al tránsito gastrointestinal, dado que es uno de los factores más importantes en la evaluación de cepas con potencial actividad probiótica.

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