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Gastrointestinal Environment (gastrointestinal + environment)
Selected AbstractsExported proteins in probiotic bacteria: adhesion to intestinal surfaces, host immunomodulation and molecular cross-talking with the hostFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 1 2008Borja Sánchez Abstract The group of exported proteins of a bacterium are those proteins that are sorted from the cytoplasm to the bacterial surface or to the surroundings of the microorganism. In probiotic bacteria, these proteins are of special relevance because they might determine important traits such as adhesion to intestinal surfaces and molecular cross-talking with the host. Current knowledge about the presence and biological relevance of exported proteins produced by the main genera of probiotic bacteria in the gastrointestinal environment is reviewed in this minireview. As will be seen, some of these proteins are involved in host adhesion or are able to modify certain signalization pathways within host cells, whereas others are important for the physiology of probiotic bacteria in the gastrointestinal tract. [source] VIRULENCE RESPONSE OF A SALMONELLA TYPHIMURIUM HILA:LACZY FUSION STRAIN TO SPENT MEDIA FROM PURE CULTURES OF SELECTED BACTERIA AND POULTRY CECAL MIXED CULTUREJOURNAL OF FOOD SAFETY, Issue 3 2002J.D. NUTT ABSTRACT Virulence gene expression in Salmonella is triggered by a variety of environmental factors including changes in the gastrointestinal environment of birds during different dietary regimes. The objective of this study was to determine if growth of specific microorganisms alters the environmental conditions sufficiently to signal Salmonella Typhimurium virulence response. Spent media was obtained from a Salmonella Typhimurium hilA:lacZY fusion strain, a poultry Salmonella Typhimurium strain, Eschcrichia coli K12, and Lactobacillus caseii Spent media samples were collected after 2, 4, 8 and 24 h of growth in brain heart infusion broth (BHI) and M9 media, ,-galactosidase assays were performed on the samples to determine virulence expression. Virulence response to Salmonella, spent media was 2-fold greater than Lactobacillus spent media at 4, 8 and 24 h growth (P < 0.05). Virulence expression almost doubled when exposed to Salmonella Typhimurium (NONA) spent media compared to mixed culture spent media at 4 h, and Salmonella Typhimurium (NONA) was significantly higher than mixed culture spent media at 24 h (P < 0.05). Based on these results, it appears that growth of similar bacterial species may alter the composition of rich media sufficiently to influence virulence. [source] Design and In vitro evaluation of a film-controlled dosage form self-converted from monolithic tablet in gastrointestinal environmentJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2010Tingting Zhang Abstract The purpose of this study is to design an easily manufactured sustained drug delivery system, which can be converted to a film coated system during the dissolution process and then control the drug release according to near zero-order kinetics. Two kinds of pH-sensitive and oppositely charged hydrophilic polymers, chitosan and alginate, were physically mixed as the matrix. Slightly water-soluble drugs such as theophylline, aspirin, and acetaminophen were utilized as model drugs. In vitro drug release and swelling tests were undertaken in simulated gastrointestinal environments. The formation and properties of the film formed during the dissolution process were identified using different techniques. It was demonstrated that formation of the film was based on the interaction of the polymers on tablet surface with the change of system pH. In 0,4,h drug release depended on the intrinsic properties of the polymers, however, characteristics of the film played a leading role in controlling drug release after 4,h. By studying the ratio of relaxation over Fickian diffusion and relationship between tablets swelling and drug release, it was revealed that the film probably modified drug release behavior by limiting polymer erosion. The in vivo behavior of this hydrophilic matrix system will be investigated. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:4678,4690, 2010 [source] Effect of tannic acid on in vitro enzymatic hydrolysis of some protein sourcesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2003Tomás F Martínez Abstract The pH-stat system has been used to assess the effect of tannic acid (TA) on solubility and in vitro enzyme hydrolysis of different proteins. Added TA (from 10 to 50 g kg,1) decreased the extent of hydrolysis of bovine serum albumin. Enzymic hydrolysis of casein, pea meal, soybean meal, and haemoglobin (HB) was increased, as measured by total amino acids released and by the degree of hydrolysis. SDS-PAGE confirmed the results of the in vitro enzymatic hydrolysis. These findings suggest that, under in vitro conditions, when simulating the gastrointestinal environment of domestic mammals, the negative effects of TA described from in vivo experiments are not necessarily due to reduced hydrolysis of proteins. Copyright © 2003 Society of Chemical Industry [source] Design and In vitro evaluation of a film-controlled dosage form self-converted from monolithic tablet in gastrointestinal environmentJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2010Tingting Zhang Abstract The purpose of this study is to design an easily manufactured sustained drug delivery system, which can be converted to a film coated system during the dissolution process and then control the drug release according to near zero-order kinetics. Two kinds of pH-sensitive and oppositely charged hydrophilic polymers, chitosan and alginate, were physically mixed as the matrix. Slightly water-soluble drugs such as theophylline, aspirin, and acetaminophen were utilized as model drugs. In vitro drug release and swelling tests were undertaken in simulated gastrointestinal environments. The formation and properties of the film formed during the dissolution process were identified using different techniques. It was demonstrated that formation of the film was based on the interaction of the polymers on tablet surface with the change of system pH. In 0,4,h drug release depended on the intrinsic properties of the polymers, however, characteristics of the film played a leading role in controlling drug release after 4,h. By studying the ratio of relaxation over Fickian diffusion and relationship between tablets swelling and drug release, it was revealed that the film probably modified drug release behavior by limiting polymer erosion. The in vivo behavior of this hydrophilic matrix system will be investigated. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:4678,4690, 2010 [source] | ||||||||||