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Ronald R Dubreuil - One of the best experts on this subject based on the ideXlab platform.

  • copper cells and Stomach Acid Secretion in the drosophila midgut
    The International Journal of Biochemistry & Cell Biology, 2004
    Co-Authors: Ronald R Dubreuil
    Abstract:

    Abstract Copper cells in the Drosophila larval midgut were originally named for their ability to accumulate dietary copper. Recent studies have uncovered a number of intriguing similarities between copper cells and the Acid-producing gastric parietal cells of the mammalian Stomach. In addition to their shared roles in Stomach Acidification, they share a peculiar invaginated morphology in which the apical cell surface is buried deep within the cytoplasm. These shared properties of morphology and function portend the identification of shared molecular mechanisms that account for their specialized roles in digestive physiology. Cell facts: • Approximately 100 copper cells in larval middle midgut. • Orange fluorescence after copper feeding. • Specification during development is controlled by the labial gene. • Apical surface is arranged as a flask-shaped invagination. • Responsible for Stomach Acidification.

  • differential effects of a labial mutation on the development structure and function of Stomach Acid secreting cells in drosophila melanogaster larvae and adults
    Cell and Tissue Research, 2001
    Co-Authors: Ronald R Dubreuil, Tatyana A Grushko, Otto Baumann
    Abstract:

    The differentiation of copper cells, which secrete Stomach Acid in Drosophila larvae, has been shown previously to be sensitive to the labial k3 mutation. Here we found that Stomach Acid Secretion in adults was insensitive to lab k3 . The basis for this stage-specific effect was elucidated by characterizing the development, structure, and function of the adult midgut. First, we demonstrated by copper-dependent fluorescence and morphology that copper cells were present in the adult Stomach. Fine-structure analysis of adult copper cells led to the identification of a previously unrecognized plasma membrane domain: apicolateral contacts between copper cells and their neighbors consisted of smooth septate junctions that were enriched in αβ-spectrin and ankyrin. Second, we demonstrated that adult copper cells were present in lab k3 /lab vd1 (conditional/null) adults. The labial protein was expressed in adult lab k3 /lab vd1 copper cells, but not in larvae. Thus the lab k3 mutation had a stage-specific effect on midgut labial expression, but did not appear to affect protein function. Surprisingly, Stomach Acidification was dispensable during larval development, since lab k3 /lab vd1 mutant larvae that lacked midgut Acidification developed into fertile adults.

  • Drosophila β Spectrin Functions Independently of α Spectrin to Polarize the Na,k Atpase in Epithelial Cells
    Journal of Cell Biology, 2000
    Co-Authors: Ronald R Dubreuil, Ping Wang, Steve Dahl, Lawrence S.b. Goldstein
    Abstract:

    Spectrin has been proposed to function as a sorting machine that concentrates interacting proteins such as the Na,K ATPase within specialized plasma membrane domains of polarized cells. However, little direct evidence to support this model has been obtained. Here we used a genetic approach to directly test the requirement for the β subunit of the αβ spectrin molecule in morphogenesis and function of epithelial cells in Drosophila. β Spectrin mutations were lethal during late embryonic/early larval development and they produced subtle defects in midgut morphology and Stomach Acid Secretion. The polarized distributions of αβH spectrin and ankyrin were not significantly altered in β spectrin mutants, indicating that the two isoforms of Drosophila spectrin assemble independently of one another, and that ankyrin is upstream of αβ spectrin in the spectrin assembly pathway. In contrast, β spectrin mutations had a striking effect on the basolateral accumulation of the Na,K ATPase. The results establish a role for β spectrin in determining the subcellular distribution of the Na,K ATPase and, unexpectedly, this role is independent of α spectrin.

Fakhreddin Jamali - One of the best experts on this subject based on the ideXlab platform.

  • Comparative efficacy of esomeprazole and omeprazole: Racemate to single enantiomer switch
    DARU, 2015
    Co-Authors: Waheed Asghar, Elliot Pittman, Fakhreddin Jamali
    Abstract:

    Background Both omeprazole and its S enantiomer (esomeprazole) have been available and used to treat symptoms of gastroesophageal reflux disease (GERD) and conditions associated with excessive Stomach Acid Secretion for more than a decade. Controversy exists over improved efficacy of S enantiomer (esomeprazole) over parent racemate (omeprazole). However, a comparison of the clinical outcomes of these products may reveal the rationale for switching from the racemate to single enantiomer. Since enantiomers of omeprazole are equipotent, we compared the outcomes of equal doses of each product to see if both actually differ in their efficacy’s or the reported superiority of S enantiomer is just a dose effect.

  • Comparative efficacy of esomeprazole and omeprazole: Racemate to single enantiomer switch
    DARU Journal of Pharmaceutical Sciences, 2015
    Co-Authors: Waheed Asghar, Elliot Pittman, Fakhreddin Jamali
    Abstract:

    Background Both omeprazole and its S enantiomer (esomeprazole) have been available and used to treat  symptoms of gastroesophageal reflux disease (GERD) and conditions associated with excessive Stomach Acid Secretion for more than a decade. Controversy exists over improved efficacy of S enantiomer (esomeprazole) over parent racemate (omeprazole). However, a comparison of the clinical outcomes of these products may reveal the rationale for switching from the racemate to single enantiomer. Since enantiomers of omeprazole are equipotent, we compared the outcomes of equal doses of each product to see if both actually differ in their efficacy’s or the reported superiority of S enantiomer is just a dose effect. Methods A web search was carried out for randomized controlled trials with head-to-head comparisons of omeprazole and S-omeprazole. The data were abstracted and after calculating theodd ratios (OR) for the outcomes reported in each study, the combined overall odd ratios (OR’) were estimated. The random effect inverse variance method with omeprazole as the reference (OR” = 1) was used. Results Out of 1171 studies, 14 were deemed eligible. There was no significant difference in the therapeutic success between omeprazole and S-omeprazole as a part of triple therapy for the treatment of H. pylori in both intention-to-treat (OR’, 1.06; CI, 0.83, 1.36; p =  0.63) as well as per-protocol analysis (OR’, 1.07; CI, 0.84, 1.36; p =  0.57). For the treatment of gastro-oesophageal reflux disease, S-omeprazole was significantly but marginally superior to the racemate (OR’, 1.18; CI, 1.01, 1.38; p =  0.04). The two products were equipotent in all metrics used to assess intragastric pH except for the % patients maintaining a 24 h gastric pH above 4 (1.57; CI, 1.04, 2.381; p =  0.03). Conclusion The therapeutic benefit of chiral switch of omeprazole is questionable considering the substantially greater economic burden involved.

Waheed Asghar - One of the best experts on this subject based on the ideXlab platform.

  • Comparative efficacy of esomeprazole and omeprazole: Racemate to single enantiomer switch
    DARU, 2015
    Co-Authors: Waheed Asghar, Elliot Pittman, Fakhreddin Jamali
    Abstract:

    Background Both omeprazole and its S enantiomer (esomeprazole) have been available and used to treat symptoms of gastroesophageal reflux disease (GERD) and conditions associated with excessive Stomach Acid Secretion for more than a decade. Controversy exists over improved efficacy of S enantiomer (esomeprazole) over parent racemate (omeprazole). However, a comparison of the clinical outcomes of these products may reveal the rationale for switching from the racemate to single enantiomer. Since enantiomers of omeprazole are equipotent, we compared the outcomes of equal doses of each product to see if both actually differ in their efficacy’s or the reported superiority of S enantiomer is just a dose effect.

  • Comparative efficacy of esomeprazole and omeprazole: Racemate to single enantiomer switch
    DARU Journal of Pharmaceutical Sciences, 2015
    Co-Authors: Waheed Asghar, Elliot Pittman, Fakhreddin Jamali
    Abstract:

    Background Both omeprazole and its S enantiomer (esomeprazole) have been available and used to treat  symptoms of gastroesophageal reflux disease (GERD) and conditions associated with excessive Stomach Acid Secretion for more than a decade. Controversy exists over improved efficacy of S enantiomer (esomeprazole) over parent racemate (omeprazole). However, a comparison of the clinical outcomes of these products may reveal the rationale for switching from the racemate to single enantiomer. Since enantiomers of omeprazole are equipotent, we compared the outcomes of equal doses of each product to see if both actually differ in their efficacy’s or the reported superiority of S enantiomer is just a dose effect. Methods A web search was carried out for randomized controlled trials with head-to-head comparisons of omeprazole and S-omeprazole. The data were abstracted and after calculating theodd ratios (OR) for the outcomes reported in each study, the combined overall odd ratios (OR’) were estimated. The random effect inverse variance method with omeprazole as the reference (OR” = 1) was used. Results Out of 1171 studies, 14 were deemed eligible. There was no significant difference in the therapeutic success between omeprazole and S-omeprazole as a part of triple therapy for the treatment of H. pylori in both intention-to-treat (OR’, 1.06; CI, 0.83, 1.36; p =  0.63) as well as per-protocol analysis (OR’, 1.07; CI, 0.84, 1.36; p =  0.57). For the treatment of gastro-oesophageal reflux disease, S-omeprazole was significantly but marginally superior to the racemate (OR’, 1.18; CI, 1.01, 1.38; p =  0.04). The two products were equipotent in all metrics used to assess intragastric pH except for the % patients maintaining a 24 h gastric pH above 4 (1.57; CI, 1.04, 2.381; p =  0.03). Conclusion The therapeutic benefit of chiral switch of omeprazole is questionable considering the substantially greater economic burden involved.

Otto Baumann - One of the best experts on this subject based on the ideXlab platform.

  • differential effects of a labial mutation on the development structure and function of Stomach Acid secreting cells in drosophila melanogaster larvae and adults
    Cell and Tissue Research, 2001
    Co-Authors: Ronald R Dubreuil, Tatyana A Grushko, Otto Baumann
    Abstract:

    The differentiation of copper cells, which secrete Stomach Acid in Drosophila larvae, has been shown previously to be sensitive to the labial k3 mutation. Here we found that Stomach Acid Secretion in adults was insensitive to lab k3 . The basis for this stage-specific effect was elucidated by characterizing the development, structure, and function of the adult midgut. First, we demonstrated by copper-dependent fluorescence and morphology that copper cells were present in the adult Stomach. Fine-structure analysis of adult copper cells led to the identification of a previously unrecognized plasma membrane domain: apicolateral contacts between copper cells and their neighbors consisted of smooth septate junctions that were enriched in αβ-spectrin and ankyrin. Second, we demonstrated that adult copper cells were present in lab k3 /lab vd1 (conditional/null) adults. The labial protein was expressed in adult lab k3 /lab vd1 copper cells, but not in larvae. Thus the lab k3 mutation had a stage-specific effect on midgut labial expression, but did not appear to affect protein function. Surprisingly, Stomach Acidification was dispensable during larval development, since lab k3 /lab vd1 mutant larvae that lacked midgut Acidification developed into fertile adults.

Veronika Somoza - One of the best experts on this subject based on the ideXlab platform.

  • measurement of the intracellular ph in human Stomach cells a novel approach to evaluate the gastric Acid secretory potential of coffee beverages
    Journal of Agricultural and Food Chemistry, 2010
    Co-Authors: Carola Weiss, Malte Rubach, Roman Lang, Elisabeth Seebach, Simone Blumberg, Oliver Frank, Thomas Hofmann, Veronika Somoza
    Abstract:

    As the consumption of coffee beverages sometimes is reported to cause gastric irritation, for which an increased Stomach Acid Secretion is one of the promoting factors, different processing technologies such as steam-treatment have been developed to reduce putative Stomach irritating compounds. There is evidence-based data neither on the effect of detailed processing variations nor on individual coffee components affecting the proton secretory activity (PSA). This work aimed at developing a screening model suitable for investigating the effects of commercial coffee beverages and components thereof on human parietal cells. Human gastric cancer cells (HGT-1) were treated with reconstituted freeze-dried coffee beverages prepared from customary coffee products such as regular coffee (RC, n = 4), mild bean coffee (MBC, n = 5), Stomach friendly coffee (SFC, n = 4), and SFC decaffeinated (SFCD, n = 3). PSA was analyzed by flow cytometry using the pH-sensitive dye SNARF-AM. Treatment of the cells with MBC did not...