The Experts below are selected from a list of 24030 Experts worldwide ranked by ideXlab platform

Kaiming Chan - One of the best experts on this subject based on the ideXlab platform.

  • local administration of trolox a vitamin e analog reduced tendon adhesion in a Chicken Model of flexor digitorum profundus tendon injury
    Journal of orthopaedic translation, 2017
    Co-Authors: Yukwa Lee, Kaiming Chan, Tsuiyu Mok, Leungkim Hung
    Abstract:

    Summary Background Hand flexor tendon injuries are compromised with tendon adhesion. Tendon adhesion forms between flexor tendon and tendon sheath, reduces the range of motion of fingers, and affects their function. Oxidative stress is increased in flexor tendon after injury and might play a role in tendon adhesion formation. Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), a water-soluble analog of vitamin E, is antioxidative. Trolox reduced oxidative stress and the expression of fibrotic cytokines in the bile gut ligation animal Model. Vitamin C and Trolox are strong antioxidants, but they might also have prooxidant properties. The prooxidant properties of vitamin C and Trolox are different. In this study, our aim was to determine the effect of Trolox in reducing tendon adhesion formation. Methods Flexor digitorum profundus tendon injury was induced in 54 Kai-Mei Chicken according to a well-established protocol. After wound closure, an injection of 50 μL saline, 10mM Trolox, or 100mM Trolox was administered into the wound area. At 2 weeks or 6 weeks after the surgery, Chicken feet were harvested for gliding test, high-resolution ultrasound measurement on a fibrotic area, and histology. Results At Week 2 after the surgery, Trolox has no effect on the flexion angle and gliding resistance, whereas a significant improvement was observed in the flexion angle and gliding resistance in the Trolox-treated groups at Week 6. However, no dose response was observed. In the ultrasound measurement, there was no significant difference in the fibrotic mass in the Trolox-treated group as compared to the saline group at Week 2. At Week 6, fibrotic mass was significantly reduced in both Trolox-treated groups. From the histological examination, the Trolox-treated groups presented a higher cellularity at Week 2 as compared to the saline group, and reduced fibrosis and adhesion at Week 6. Conclusion Our results suggest that local administration of Trolox can reduce tendon adhesion, and a higher dose of Trolox did not have negative effects. Clinical Significance Trolox solution might be feasible to reduce tendon adhesion via intraoperative injection at the wound area during tendon repair.

  • local vitamin c injection reduced tendon adhesion in a Chicken Model of flexor digitorum profundus tendon injury
    Journal of Bone and Joint Surgery American Volume, 2013
    Co-Authors: Leungkim Hung, Yukwa Lee, Tsuiyu Mok, Kaiming Chan
    Abstract:

    Background: Adhesion formation is a complication of hand flexor tendon repair. Normal gliding function of flexor tendons can be impaired by an excessive fibrotic response, which may be caused by intraoperative and postoperative hemorrhage. As tissue damage and hemorrhage can disturb redox regulation, thereby favoring fibrotic responses, the purpose of this study was to investigate if antioxidants can reduce tendon adhesion by antagonizing oxidative stress. Methods: Flexor digitorum profundus tendon injury was induced in fifty-seven Chickens. In twelve Chickens, oxidative stress preinjury, immediately after injury, and two and six weeks postinjury (n = 3 at each time period) was estimated by measuring tissue levels of the reduced form of glutathione (GSH) and oxidized glutathione (glutathione disulfide [GSSG]) in the proximal interphalangeal joint. In the remaining Chickens, 50 μL of saline solution or vitamin-C solution (5 or 50 mg/mL) was injected into the wound immediately after closure of the tendon sheath. Samples were harvested at two weeks (n = 6 in each group) or six weeks (n = 6 in each group) postinjury for a gliding test, ultrasound imaging, and histological examination. Three Chickens from each group were killed at two weeks postinjury for GSH and GSSG measurements to evaluate the treatment effects on postoperative oxidative stress. Results: The GSH level was significantly decreased at two and six weeks postinjury, and the GSSG level was significantly increased at six weeks postinjury. Both 5 and 50-mg/mL vitamin C led to higher tissue levels of GSH at two weeks postinjury, as compared with that in the saline solution group, but no significant change in the GSSG level was detected. Chickens with vitamin-C supplementation showed no significant improvement in gliding resistance and no significant reduction of the fibrotic size at two weeks postinjury, but they did show significant improvement in gliding resistance at six weeks postinjury and the 5-mg/mL vitamin-C group showed a significant reduction of the fibrotic size at six weeks. Histological examination showed less peritendinous adhesion in the vitamin-C groups. Conclusions: Our results suggest that local injection of vitamin-C solution can reduce the extent of adhesion of healing tendons, probably by redox modulation, in a Chicken Model. Clinical Relevance: It may be feasible to apply vitamin-C solution intraoperatively at the time of tendon repair to reduce restrictive tendon adhesion, but additional studies are needed to optimize the dose required.

Ramesh Ramachandran - One of the best experts on this subject based on the ideXlab platform.

  • expression of adiponectin and its receptors is altered in epithelial ovarian tumors and ascites derived ovarian cancer cell lines
    International Journal of Gynecological Cancer, 2015
    Co-Authors: Anupama Tiwari, Jill A. Hadley, Olga M Ocongrove, James R Giles, Patricia A Johnson, Ramesh Ramachandran
    Abstract:

    Objectives Recent evidence suggests that higher body mass index is associated with a modest increase in ovarian cancer risk. Reduced serum levels of adiponectin are correlated with obesity and increased cancer risk. The objectives of the present study are to determine if expressions of adiponectin and its receptors, AdipoR1 and AdipoR2, are altered in epithelial ovarian tumors and ascites-derived ovarian cancer cell lines and to determine if plasma adiponectin levels are altered in the Chicken Model of ovarian cancer. Methods Adiponectin, AdipoR1, and AdipoR2 mRNA concentrations in ovaries and Chicken ovarian cancer (COVCAR) cell lines were determined by quantitative real-time polymerase chain reaction analysis. Existence of adiponectin isoforms in the ovaries and COVCAR cells was identified by nondenaturing gel electrophoresis. Adiponectin, AdipoR1, and AdipoR2 protein amounts were determined by Western blot analysis. Plasma total adiponectin levels were determined by an enzyme immunoassay. Results Adiponectin, AdipoR1, and AdipoR2 mRNA concentrations were significantly lower in cancerous ovaries and COVCAR cell lines compared with normal ovaries and normal ovarian surface epithelial (NOSE) cells, respectively. Adiponectin in ovary and COVCAR cell lines appeared as a heavy-molecular-weight isoform that is greater than 720-kd mass. In addition, a lower-molecular-weight adiponectin isoform was found in COVCAR cells but not in NOSE cells. Adiponectin and AdipoR1 protein concentrations were not different in COVCAR cell lines compared with NOSE cells. However, AdipoR2 protein concentrations were significantly higher in cancerous ovaries but lower in COVCAR cell lines compared with normal ovaries and NOSE cells, respectively. Plasma adiponectin concentrations were not different in Chickens that had ovarian carcinoma compared with control animals. Conclusions Expression of adiponectin in ovarian tumors and in metastatic ovarian tumor cells is likely to affect cellular metabolism and proliferation through activating AdipoR1 and/or AdipoR2. Plasma adiponectin levels may not be predictive of advanced stages of ovarian tumor in the Chicken Model.

  • Aquaporin 5 expression is altered in ovarian tumors and ascites-derived ovarian tumor cells in the Chicken Model of ovarian tumor.
    Journal of ovarian research, 2014
    Co-Authors: Anupama Tiwari, Jill A. Hadley, Ramesh Ramachandran
    Abstract:

    Background Aquaporin 5 (AQP5), a member of the aquaporin family of transmembrane channel proteins, is involved in water transport and cellular proliferation in various tumors. The objective of this study was to determine cellular localization of aquaporin 5 (AQP5) in the ovarian tumors of Chicken, a preclinical Model for human ovarian tumor and to determine if AQP5 mRNA and protein expression levels in cancerous Chicken ovaries and in ascites-derived Chicken ovarian cancer (COVCAR) cell lines are different from normal ovaries and normal ovarian surface epithelial (NOSE) cells, respectively.

Leungkim Hung - One of the best experts on this subject based on the ideXlab platform.

  • local administration of trolox a vitamin e analog reduced tendon adhesion in a Chicken Model of flexor digitorum profundus tendon injury
    Journal of orthopaedic translation, 2017
    Co-Authors: Yukwa Lee, Kaiming Chan, Tsuiyu Mok, Leungkim Hung
    Abstract:

    Summary Background Hand flexor tendon injuries are compromised with tendon adhesion. Tendon adhesion forms between flexor tendon and tendon sheath, reduces the range of motion of fingers, and affects their function. Oxidative stress is increased in flexor tendon after injury and might play a role in tendon adhesion formation. Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), a water-soluble analog of vitamin E, is antioxidative. Trolox reduced oxidative stress and the expression of fibrotic cytokines in the bile gut ligation animal Model. Vitamin C and Trolox are strong antioxidants, but they might also have prooxidant properties. The prooxidant properties of vitamin C and Trolox are different. In this study, our aim was to determine the effect of Trolox in reducing tendon adhesion formation. Methods Flexor digitorum profundus tendon injury was induced in 54 Kai-Mei Chicken according to a well-established protocol. After wound closure, an injection of 50 μL saline, 10mM Trolox, or 100mM Trolox was administered into the wound area. At 2 weeks or 6 weeks after the surgery, Chicken feet were harvested for gliding test, high-resolution ultrasound measurement on a fibrotic area, and histology. Results At Week 2 after the surgery, Trolox has no effect on the flexion angle and gliding resistance, whereas a significant improvement was observed in the flexion angle and gliding resistance in the Trolox-treated groups at Week 6. However, no dose response was observed. In the ultrasound measurement, there was no significant difference in the fibrotic mass in the Trolox-treated group as compared to the saline group at Week 2. At Week 6, fibrotic mass was significantly reduced in both Trolox-treated groups. From the histological examination, the Trolox-treated groups presented a higher cellularity at Week 2 as compared to the saline group, and reduced fibrosis and adhesion at Week 6. Conclusion Our results suggest that local administration of Trolox can reduce tendon adhesion, and a higher dose of Trolox did not have negative effects. Clinical Significance Trolox solution might be feasible to reduce tendon adhesion via intraoperative injection at the wound area during tendon repair.

  • local vitamin c injection reduced tendon adhesion in a Chicken Model of flexor digitorum profundus tendon injury
    Journal of Bone and Joint Surgery American Volume, 2013
    Co-Authors: Leungkim Hung, Yukwa Lee, Tsuiyu Mok, Kaiming Chan
    Abstract:

    Background: Adhesion formation is a complication of hand flexor tendon repair. Normal gliding function of flexor tendons can be impaired by an excessive fibrotic response, which may be caused by intraoperative and postoperative hemorrhage. As tissue damage and hemorrhage can disturb redox regulation, thereby favoring fibrotic responses, the purpose of this study was to investigate if antioxidants can reduce tendon adhesion by antagonizing oxidative stress. Methods: Flexor digitorum profundus tendon injury was induced in fifty-seven Chickens. In twelve Chickens, oxidative stress preinjury, immediately after injury, and two and six weeks postinjury (n = 3 at each time period) was estimated by measuring tissue levels of the reduced form of glutathione (GSH) and oxidized glutathione (glutathione disulfide [GSSG]) in the proximal interphalangeal joint. In the remaining Chickens, 50 μL of saline solution or vitamin-C solution (5 or 50 mg/mL) was injected into the wound immediately after closure of the tendon sheath. Samples were harvested at two weeks (n = 6 in each group) or six weeks (n = 6 in each group) postinjury for a gliding test, ultrasound imaging, and histological examination. Three Chickens from each group were killed at two weeks postinjury for GSH and GSSG measurements to evaluate the treatment effects on postoperative oxidative stress. Results: The GSH level was significantly decreased at two and six weeks postinjury, and the GSSG level was significantly increased at six weeks postinjury. Both 5 and 50-mg/mL vitamin C led to higher tissue levels of GSH at two weeks postinjury, as compared with that in the saline solution group, but no significant change in the GSSG level was detected. Chickens with vitamin-C supplementation showed no significant improvement in gliding resistance and no significant reduction of the fibrotic size at two weeks postinjury, but they did show significant improvement in gliding resistance at six weeks postinjury and the 5-mg/mL vitamin-C group showed a significant reduction of the fibrotic size at six weeks. Histological examination showed less peritendinous adhesion in the vitamin-C groups. Conclusions: Our results suggest that local injection of vitamin-C solution can reduce the extent of adhesion of healing tendons, probably by redox modulation, in a Chicken Model. Clinical Relevance: It may be feasible to apply vitamin-C solution intraoperatively at the time of tendon repair to reduce restrictive tendon adhesion, but additional studies are needed to optimize the dose required.

Otero Carrera Jennifer - One of the best experts on this subject based on the ideXlab platform.

  • Biodistribución de bacteriófagos en mamíferos tras terapia fágica oral y emergencia de resistencia bacteriana a los fagos /
    2020
    Co-Authors: Otero Carrera Jennifer, Universitat Autònoma De Barcelona. Departament De Genètica I De Microbi
    Abstract:

    Departament responsable de la tesi: Departament de Genètica i de Microbiologia.La aplicación terapéutica de bacteriófagos líticos como alternativa a los antimicrobianos tradicionales ha resurgido en los últimos años. Sin embargo, existen algunos aspectos asociados a la terapia fágica que necesitan estudiarse con más profundidad para permitir su definitiva implementación. El presente trabajo se centra en el estudio de dos aspectos de especial relevancia: i) la emergencia de la resistencia a los bacteriófagos en diferentes condiciones de aplicación y ii) la biodistribución y transcitosis de bacteriófagos encapsulados en liposomas tras su administración por vía oral en un Modelo murino. Para el estudio de la emergencia de la resistencia bacteriana a bacteriófagos se utilizó el Modelo de Salmonella/cóctel de bacteriófagos integrado por UAB_Phi20, UAB_Phi78 y UAB_Phi87, cuyos receptores se localizaban en el LPS. Se evidenció que la emergencia de resistencia difería en función del ámbito de aplicación. Así, el 92 % de los aislados de cultivos in vitro de S. Typhimurium infectados con el cóctel de bacteriófagos fueron resistentes a los 3 fagos, siendo la causa probable de la resistencia la pérdida de la proteína RfaJ, implicada en la síntesis del LPS. Análogamente, en lonchas de jamón cocido contaminadas con S. Typhimurium y tratadas con el cóctel fágico, el 1,4 % de los aislados fueron resistentes a los tres fagos, mostrando también una mutación en el gen rfaJ; mientras que el 1,8 % sólo presentó resistencia a los fagos UAB_Phi20 y UAB_Phi78, debido a cambios en el gen rfc, el cual codifica la polimerasa del antígeno O. Finalmente, en los estudios de terapia fágica en el Modelo de pollo de engorde, no se encontró ningún clon resistente al fago UAB_Phi78 aislado de animales contaminados con S. Typhimurium y tratados con el cóctel. Sin embargo, el 8,5 % de los aislados del grupo control fueron resistentes a los tres fagos, no habiéndose podido determinar la causa de dicha resistencia. Por otro lado, el 1,3 % y el 3,3 % de los clones de los animales del grupo control y tratamiento, respectivamente, mostraron resistencia al bacteriófago UAB_Phi78, el cual ejerció un efecto bactericida, pero no bacteriolítico y sin producción de progenie fágica y resistencia asociada a UAB_Phi87. Aunque la causa de dicha resistencia no se ha podido identificar, todo sugiere la implicación de un mecanismo basado en una infección abortiva. En conclusión, este estudio revela que tanto la frecuencia de la emergencia de resistencia como los mecanismos causantes de la misma son diferentes in vitro, en alimentos e in vivo. Además, demuestra la necesidad de abordar los estudios de resistencia de un modo más amplio y de utilizar cócteles que contengan bacteriófagos que reconozcan diferentes receptores para disminuir el desarrollo de resistencias. En el estudio de biodistribución, se administró oralmente el fago UAB_Phi20 encapsulado en liposomas y marcado con el fluorocromo VTS-750 a ratones y visualizándolos mediante el sistema IVIS Spectrum. Esta metodología combinada con métodos de cultivo ex vivo, demostró que la encapsulación daba lugar a un aumento significativo de fagos encapsulados en el estómago 6 h después de su administración. Igualmente, los bacteriófagos encapsulados en liposomas también se encontraron en el bazo, hígado y músculo. Por otro lado, la aplicación de CLSM en cultivos in vitro de células intestinales humanas (Caco-2/HT29/Raji-B) reveló que los liposomas se adhieren a las membranas de dichas células pudiendo permanecer en su interior. En cambio, los bacteriófagos no encapsulados son capaces de translocar la barrera intestinal. Así, la prolongada persistencia de los fagos encapsulados en el estómago y su adherencia a la membrana intestinal podría explicar la mayor eficacia en el tiempo de la terapia fágica oral empleando bacteriófagos encapsulados en liposomas.Interest in the therapeutic application of virulent bacteriophages as an alternative to traditional antimicrobials has re-emerged in recent years. However, more detailed studies of several aspects associated with phage therapy are needed to allow its definitive implementation. The aim of the research presented in this dissertation was to study i) the emergence of resistance to bacteriophages under different conditions of their application and ii) the biodistribution and transcytosis of liposome-encapsulated bacteriophages after oral administration in a murine Model. The study of bacteriophage resistance made use of the Model Salmonella/bacteriophage cocktail composed of the phages UAB_Phi20, UAB_Phi78, and UAB_Phi87, whose receptors involving the LPS. The results showed that the emergence of resistance differed depending on the scope of the application. Thus, 92 % of the isolates recovered from in vitro cultures of S. Typhimurium infected with the bacteriophage cocktail were resistant to the three bacteriophages. This form of resistance was probably due to the loss of the RfaJ protein, involved in the synthesis of Salmonella LPS. Similarly, in slices of cooked ham contaminated with S. Typhimurium and treated with the phage cocktail, 1.4 % of the clones were resistant to the three bacteriophages, also showing mutations in the rfaJ gene; meanwhile, only 1.8 % of the clones were resistant to UAB_Phi20 and UAB_Phi78 due to changes in the rfc gene, encoding the O-antigen polymerase. Finally, in studies of phage therapy in a broiler Chicken Model, no resistance to UAB_Phi78 was found in isolates from animals contaminated with S. Typhimurium and treated with the phage cocktail. However, 8.5 % of the isolates in the control group were resistant to the three phages, not having been determined the mechanisms of this resistance. In addition, 1.3 % and 3.3 % of the clones in the animals of the control and treated group, respectively, were resistant to bacteriophage UAB_Phi78, which exerted a bactericidal but not a bacteriolytic effect and did not result in the production of phage progeny, and additionally showed resistance to UAB_Phi87. The cause of this resistance was also unclear but the evidence suggested a mechanism based on an abortive infection. In conclusion, this study showed that both the frequency of the emergence of resistance and the mechanisms involved differ in vitro, in food, and in vivo. It, therefore, demonstrates the need for a broader approach to resistance studies and the use of cocktails containing bacteriophages that by recognizing different host receptors reduce the development of resistance. The biodistribution studies were performed by orally administering to mice the liposome-encapsulated phage UAB_Phi20 labeled with VTS-750 fluorochrome and then visualizing the phages by the IVIS Spectrum methodology. Using this method together with ex vivo cultures, we were able to show that encapsulation resulted in a significant accumulation of encapsulated phages in the mouse stomach, even 6 h after phage administration. Similarly, liposome-encapsulated phages were found in spleen, liver, and muscle. By contrast, in CLSM study of in vitro cultures of human intestinal cells (Caco-2/HT29/Raji-B), liposomes were seen adhered to the cell membrane or embedded in this. However, non-encapsulated bacteriophages were able to translocate across the intestinal barrier. Taken together, these results could explain the greater efficacy over time of oral phage therapy using liposome-encapsulated bacteriophages

  • Biodistribución de bacteriófagos en mamíferos tras terapia fágica oral y emergencia de resistencia bacteriana a los fagos
    'Universitat Autonoma de Barcelona', 2019
    Co-Authors: Otero Carrera Jennifer
    Abstract:

    La aplicación terapéutica de bacteriófagos líticos como alternativa a los antimicrobianos tradicionales ha resurgido en los últimos años. Sin embargo, existen algunos aspectos asociados a la terapia fágica que necesitan estudiarse con más profundidad para permitir su definitiva implementación. El presente trabajo se centra en el estudio de dos aspectos de especial relevancia: i) la emergencia de la resistencia a los bacteriófagos en diferentes condiciones de aplicación y ii) la biodistribución y transcitosis de bacteriófagos encapsulados en liposomas tras su administración por vía oral en un Modelo murino. Para el estudio de la emergencia de la resistencia bacteriana a bacteriófagos se utilizó el Modelo de Salmonella/cóctel de bacteriófagos integrado por UAB_Phi20, UAB_Phi78 y UAB_Phi87, cuyos receptores se localizaban en el LPS. Se evidenció que la emergencia de resistencia difería en función del ámbito de aplicación. Así, el 92 % de los aislados de cultivos in vitro de S. Typhimurium infectados con el cóctel de bacteriófagos fueron resistentes a los 3 fagos, siendo la causa probable de la resistencia la pérdida de la proteína RfaJ, implicada en la síntesis del LPS. Análogamente, en lonchas de jamón cocido contaminadas con S. Typhimurium y tratadas con el cóctel fágico, el 1,4 % de los aislados fueron resistentes a los tres fagos, mostrando también una mutación en el gen rfaJ; mientras que el 1,8 % sólo presentó resistencia a los fagos UAB_Phi20 y UAB_Phi78, debido a cambios en el gen rfc, el cual codifica la polimerasa del antígeno O. Finalmente, en los estudios de terapia fágica en el Modelo de pollo de engorde, no se encontró ningún clon resistente al fago UAB_Phi78 aislado de animales contaminados con S. Typhimurium y tratados con el cóctel. Sin embargo, el 8,5 % de los aislados del grupo control fueron resistentes a los tres fagos, no habiéndose podido determinar la causa de dicha resistencia. Por otro lado, el 1,3 % y el 3,3 % de los clones de los animales del grupo control y tratamiento, respectivamente, mostraron resistencia al bacteriófago UAB_Phi78, el cual ejerció un efecto bactericida, pero no bacteriolítico y sin producción de progenie fágica y resistencia asociada a UAB_Phi87. Aunque la causa de dicha resistencia no se ha podido identificar, todo sugiere la implicación de un mecanismo basado en una infección abortiva. En conclusión, este estudio revela que tanto la frecuencia de la emergencia de resistencia como los mecanismos causantes de la misma son diferentes in vitro, en alimentos e in vivo. Además, demuestra la necesidad de abordar los estudios de resistencia de un modo más amplio y de utilizar cócteles que contengan bacteriófagos que reconozcan diferentes receptores para disminuir el desarrollo de resistencias. En el estudio de biodistribución, se administró oralmente el fago UAB_Phi20 encapsulado en liposomas y marcado con el fluorocromo VTS-750 a ratones y visualizándolos mediante el sistema IVIS Spectrum. Esta metodología combinada con métodos de cultivo ex vivo, demostró que la encapsulación daba lugar a un aumento significativo de fagos encapsulados en el estómago 6 h después de su administración. Igualmente, los bacteriófagos encapsulados en liposomas también se encontraron en el bazo, hígado y músculo. Por otro lado, la aplicación de CLSM en cultivos in vitro de células intestinales humanas (Caco-2/HT29/Raji-B) reveló que los liposomas se adhieren a las membranas de dichas células pudiendo permanecer en su interior. En cambio, los bacteriófagos no encapsulados son capaces de translocar la barrera intestinal. Así, la prolongada persistencia de los fagos encapsulados en el estómago y su adherencia a la membrana intestinal podría explicar la mayor eficacia en el tiempo de la terapia fágica oral empleando bacteriófagos encapsulados en liposomas.Interest in the therapeutic application of virulent bacteriophages as an alternative to traditional antimicrobials has re-emerged in recent years. However, more detailed studies of several aspects associated with phage therapy are needed to allow its definitive implementation. The aim of the research presented in this dissertation was to study i) the emergence of resistance to bacteriophages under different conditions of their application and ii) the biodistribution and transcytosis of liposome-encapsulated bacteriophages after oral administration in a murine Model. The study of bacteriophage resistance made use of the Model Salmonella/bacteriophage cocktail composed of the phages UAB_Phi20, UAB_Phi78, and UAB_Phi87, whose receptors involving the LPS. The results showed that the emergence of resistance differed depending on the scope of the application. Thus, 92 % of the isolates recovered from in vitro cultures of S. Typhimurium infected with the bacteriophage cocktail were resistant to the three bacteriophages. This form of resistance was probably due to the loss of the RfaJ protein, involved in the synthesis of Salmonella LPS. Similarly, in slices of cooked ham contaminated with S. Typhimurium and treated with the phage cocktail, 1.4 % of the clones were resistant to the three bacteriophages, also showing mutations in the rfaJ gene; meanwhile, only 1.8 % of the clones were resistant to UAB_Phi20 and UAB_Phi78 due to changes in the rfc gene, encoding the O-antigen polymerase. Finally, in studies of phage therapy in a broiler Chicken Model, no resistance to UAB_Phi78 was found in isolates from animals contaminated with S. Typhimurium and treated with the phage cocktail. However, 8.5 % of the isolates in the control group were resistant to the three phages, not having been determined the mechanisms of this resistance. In addition, 1.3 % and 3.3 % of the clones in the animals of the control and treated group, respectively, were resistant to bacteriophage UAB_Phi78, which exerted a bactericidal but not a bacteriolytic effect and did not result in the production of phage progeny, and additionally showed resistance to UAB_Phi87. The cause of this resistance was also unclear but the evidence suggested a mechanism based on an abortive infection. In conclusion, this study showed that both the frequency of the emergence of resistance and the mechanisms involved differ in vitro, in food, and in vivo. It, therefore, demonstrates the need for a broader approach to resistance studies and the use of cocktails containing bacteriophages that by recognizing different host receptors reduce the development of resistance. The biodistribution studies were performed by orally administering to mice the liposome-encapsulated phage UAB_Phi20 labeled with VTS-750 fluorochrome and then visualizing the phages by the IVIS Spectrum methodology. Using this method together with ex vivo cultures, we were able to show that encapsulation resulted in a significant accumulation of encapsulated phages in the mouse stomach, even 6 h after phage administration. Similarly, liposome-encapsulated phages were found in spleen, liver, and muscle. By contrast, in CLSM study of in vitro cultures of human intestinal cells (Caco-2/HT29/Raji-B), liposomes were seen adhered to the cell membrane or embedded in this. However, non-encapsulated bacteriophages were able to translocate across the intestinal barrier. Taken together, these results could explain the greater efficacy over time of oral phage therapy using liposome-encapsulated bacteriophages

Anupama Tiwari - One of the best experts on this subject based on the ideXlab platform.

  • expression of adiponectin and its receptors is altered in epithelial ovarian tumors and ascites derived ovarian cancer cell lines
    International Journal of Gynecological Cancer, 2015
    Co-Authors: Anupama Tiwari, Jill A. Hadley, Olga M Ocongrove, James R Giles, Patricia A Johnson, Ramesh Ramachandran
    Abstract:

    Objectives Recent evidence suggests that higher body mass index is associated with a modest increase in ovarian cancer risk. Reduced serum levels of adiponectin are correlated with obesity and increased cancer risk. The objectives of the present study are to determine if expressions of adiponectin and its receptors, AdipoR1 and AdipoR2, are altered in epithelial ovarian tumors and ascites-derived ovarian cancer cell lines and to determine if plasma adiponectin levels are altered in the Chicken Model of ovarian cancer. Methods Adiponectin, AdipoR1, and AdipoR2 mRNA concentrations in ovaries and Chicken ovarian cancer (COVCAR) cell lines were determined by quantitative real-time polymerase chain reaction analysis. Existence of adiponectin isoforms in the ovaries and COVCAR cells was identified by nondenaturing gel electrophoresis. Adiponectin, AdipoR1, and AdipoR2 protein amounts were determined by Western blot analysis. Plasma total adiponectin levels were determined by an enzyme immunoassay. Results Adiponectin, AdipoR1, and AdipoR2 mRNA concentrations were significantly lower in cancerous ovaries and COVCAR cell lines compared with normal ovaries and normal ovarian surface epithelial (NOSE) cells, respectively. Adiponectin in ovary and COVCAR cell lines appeared as a heavy-molecular-weight isoform that is greater than 720-kd mass. In addition, a lower-molecular-weight adiponectin isoform was found in COVCAR cells but not in NOSE cells. Adiponectin and AdipoR1 protein concentrations were not different in COVCAR cell lines compared with NOSE cells. However, AdipoR2 protein concentrations were significantly higher in cancerous ovaries but lower in COVCAR cell lines compared with normal ovaries and NOSE cells, respectively. Plasma adiponectin concentrations were not different in Chickens that had ovarian carcinoma compared with control animals. Conclusions Expression of adiponectin in ovarian tumors and in metastatic ovarian tumor cells is likely to affect cellular metabolism and proliferation through activating AdipoR1 and/or AdipoR2. Plasma adiponectin levels may not be predictive of advanced stages of ovarian tumor in the Chicken Model.

  • Aquaporin 5 expression is altered in ovarian tumors and ascites-derived ovarian tumor cells in the Chicken Model of ovarian tumor.
    Journal of ovarian research, 2014
    Co-Authors: Anupama Tiwari, Jill A. Hadley, Ramesh Ramachandran
    Abstract:

    Background Aquaporin 5 (AQP5), a member of the aquaporin family of transmembrane channel proteins, is involved in water transport and cellular proliferation in various tumors. The objective of this study was to determine cellular localization of aquaporin 5 (AQP5) in the ovarian tumors of Chicken, a preclinical Model for human ovarian tumor and to determine if AQP5 mRNA and protein expression levels in cancerous Chicken ovaries and in ascites-derived Chicken ovarian cancer (COVCAR) cell lines are different from normal ovaries and normal ovarian surface epithelial (NOSE) cells, respectively.