Study on the Preparation of Lansoprazole Enteric-coated Pellets Orally Disintegrating Tablets / 中国药师

Objective:To prepare lansoprazole enteric-coated pellets and compress them into orally disintegrating tablets , and e-valuate the acid resistance in the acid stage and the in vitro dissolution in the buffer stage .Methods:Lansoprazole enteric-coated pel-lets were prepared by fluid bed coating technology , and the effects of the ratio of methacrylic acid copolymer dispersion to ethyl acrylate–methyl methacrylate copolymer dispersion , the concentration of triethyl citrate and the main pressure on the acid resistance in the acid stage and the in vitro dissolution in the buffer stage were evaluated .The similarity of the self-prepared orally disintegrating tablets and the reference preparation was evaluated by using f 2 similarity factor method .Results:The average particle size of microcrystalline cellulose core was 150-180 μm, the ratio of methacrylic acid copolymer dispersion to ethyl acrylate –methyl methacrylate copolymer dispersion was adjusted to 8:2, the enteric-coated weight was 30％, 20％triethyl citrate was used and the main pressure was controlled within the range of 10-16 kN.Lansoprazole enteric-coated pellets had sufficiently flexibility and stability against the compression force . The enteric coating did not break , showing good acid resistance .The dissolution similarity factor of the self-prepared orally disintegra-ting tablets and the reference preparation was greater than 50.Conclusion: Lansoprazole enteric-coated pellets orally disintegrating tablets have good acid resistance and high similarity for the in vitro dissolution, which can be further amplified .

Action mechanisms of acid-resistant Streptococcus sanguis against Streptococcus mutans / 医学研究生学报

Objective Streptococcus sanguis is a possible candidate bacterium for the caries replacement therapy, which has no advantages in the acidic environment.The aim of the study was to construct acid-resistant strains of Streptococcus sanguis, determine its acid tolerance, and explore the mechanism of its antagonism against Sterptococcus mutans.Methods By gradually reducing the pH value of the medium, we constructed acid-resistant strains of Streptococcus sanguis, observed their growth and measured their acid tolerance according to their survival rate against lethal pH.We evaluated the competitive relationship between Streptococcus sanguis and Streptococcus mutans by plate experiment and detected the changes of related acid resistance genes by real-time quantitative PCR.Results The growth of Streptococcus sanguis and its acid-resistant strains were limited by the pH value, and that of Streptococcus sanguis was better in either acidic or normal environment.The lethal pH value of Streptococcus sanguis was 3.6, that of its acid-resistant strains was 2.3, and the survival rate of the acid-resistant strains was 66.59% in the pH 3.6 environment.In comparison, the lethal pH value of Streptococcus mutans was 2.5, that of its acid-resistant strains was 2.1, and the survival rate of the acid-resistant strains was 2.55% in the pH 2.5 environment.In the presence of chloramphenicol, the acid-resistant strains could not survive in the original lethal pH.In the sub-lethal pH environment, the expressions of the acid resistance-related genes Groel and Dnak in the acid-resistant strains were significantly up-regulated as compared with those in the original Streptococcus sanguis (P<0.05).Conclusion Streptococcus sanguis has an acid adaptability and can enhance acid resistance in the sub-lethal pH environment.Acid-resistant Streptococcus sanguis in the replacement therapy may provide some new ideas for the treatment of dental caries.

Some pathogenic characters of paratyphoid Salmonella enterica strains isolated from poultry

OBJECTIVE@#To investigate some pathogenic characters of Salmonella enterica strains isolated from poultry.@*METHODS@#Twenty-three genetically distinct Salmonella enterica strains, of different serovars and pulsotype, were examined for virulence traits. Resistance to gastric acid environment was estimated by measuring the percentage of survived bacterial cells after exposure for 2 h to a synthetic gastric juice. Strains were analyzed with PCR for the presence of the following virulence genes: mgtC and rhuM located on SPI-3, sopB and pipB located on SPI-5, Salmonella virulence plasmid (spv) R (spvR), spvB and spvC located on Salmonella plasmid virulence and sodCI, sopE, and gipA located on prophage. Finally, resistance to 21 antibiotics was tested with Kirby-Bauer method.@*RESULTS@#A percentage of 82.60% of strains were resistant to gastric environment after induction and 60.87% of the strains exhibited constitutive resistance too. Nineteen different virulence profiles were detected. The phage related genes sodCI and sopE and the plasmid mediated operon spvR, spvB and spvC (spvRBC) were detected in 82.60%, 47.82% and 52.17% of strains, respectively. Typhimurium and Enteritidis strains showed the highest number of virulence genes. Twenty-one different antibiotic resistance profiles were obtained and two isolates (Typhimurium and Enteritidis) resulted sensible to all the tested molecules. The ampicillin, streptomycin, sulfonamide and tetracycline resistance profile was detected in seven isolates (30.43%).@*CONCLUSION@#Our results show that paratyphoid Salmonella strains with several characters of pathogenicity, that may be cause of severe pathology in animals and humans, are circulating among poultry.

The effect of Er, Cr∶YSGG laser irradiation on the acquired acid resistance of enamel and dentin in vitro / 实用口腔医学杂志

Objective:To investigate the acid resistance of tooth hard tissues irradiated by different power outputs of Er,Cr∶YSGG laser.Methods:Samples in laser groups were irradiated using Er,Cr∶ YSGG laser with the power outputs of 2.5,3.5 and 5 W for enamel and 2 W,3 W and 4 W for dentin,respectively.The calcium and phosphate ion dissolved was measured after decalcification in lactate buffer solution for 24 h.The atomic percentage of calcium and phosphate on the surface of samples was examined by X-ray energy dispersive spectroscopy and the morphological changes were investigated by SEM.Results:In all laser groups of enamel samples except 2.5 W group calcium and phosphate ion dissolved less than in control group and block group (P＜0.05).There's no statistic difference between different power groups.Compared with control group and block group,Ca/P ratio increased(P＜0.05).There's no statistic difference of the atomic percentage of Ca and P on the surface of dentin samples between each 2 groups.SEM observation showed that the surface of the laser irradiated samples was rouph,the space among enamel fibers was increased,the dentin around dentinal tuble orifice was protruded and looked like collar flange.Conclusion:Er,Cr∶YSGG laser irradiation with a range of power is effective in increasing acquired acid resistance of dental hard tissue.There was no relationship between laser power outputs and acid resistance.

Some pathogenic characters of paratyphoid Salmonella enterica strains isolated from poultry

Objective To investigate some pathogenic characters of Salmonella enterica strains isolated from poultry. Methods Twenty-three genetically distinct Salmonella enterica strains, of different serovars and pulsotype, were examined for virulence traits. Resistance to gastric acid environment was estimated by measuring the percentage of survived bacterial cells after exposure for 2 h to a synthetic gastric juice. Strains were analyzed with PCR for the presence of the following virulence genes: mgtC and rhuM located on SPI-3, sopB and pipB located on SPI-5, Salmonella virulence plasmid (spv) R (spvR), spvB and spvC located on Salmonella plasmid virulence and sodCI, sopE, and gipA located on prophage. Finally, resistance to 21 antibiotics was tested with Kirby–Bauer method. Results A percentage of 82.60% of strains were resistant to gastric environment after induction and 60.87% of the strains exhibited constitutive resistance too. Nineteen different virulence profiles were detected. The phage related genes sodCI and sopE and the plasmid mediated operon spvR, spvB and spvC (spvRBC) were detected in 82.60%, 47.82% and 52.17% of strains, respectively. Typhimurium and Enteritidis strains showed the highest number of virulence genes. Twenty-one different antibiotic resistance profiles were obtained and two isolates (Typhimurium and Enteritidis) resulted sensible to all the tested molecules. The ampicillin, streptomycin, sulfonamide and tetracycline resistance profile was detected in seven isolates (30.43%). Conclusion Our results show that paratyphoid Salmonella strains with several characters of pathogenicity, that may be cause of severe pathology in animals and humans, are circulating among poultry.

Acid and low temperature treatments on Salmonella Enteritidis inoculated in pork and its subsequent survival in simulated gastric fluid / Ácido e baixas temperaturas sobre Salmonella Enteritidis inoculada em carne suína e sua sobrevivência subsequente ao fluido gástrico simulado

ABSTRACT: The objective of this study was to evaluate the acid resistance of Salmonella enterica serovar Enteritidis (S. Enteritidis) in stored pork and in simulated gastric fluid (SGF). A culture of S. Enteritidis was subjected to acid treatment prior to inoculation into pork, stored under refrigeration at frozen temperatures and exposed to SGF. The S. Enteritidis CCS3 and ATCC 13076 strains previously subjected to acid treatment (at pH 4.0-5.0) were inoculated in pork and stored at 4°C and -18°C. Storage at 4ºC did not affect the populations of both S. Enteritidis strains. After 84 days at -18°C, the mean population of both CCS3 and ATCC strains were reduced by 0.8 and 1.5 log cycles, respectively. Prior acid treatment did not enhance the survival of both strains at low temperatures. After acid treatment and low temperature storage, S. Enteritidis ATCC 13076 lost culturability after being exposed to SGF for 10 minutes. In contrast, S. Enteritidis CCS3 was tolerant until three hours of SGF exposure. S. Enteritidis CCS3 submitted to pH 4.0 was more tolerant to SGF exposure than when submitted to pH 4.5, 5.0 and without acid treatment. Therefore, this study indicates that exposure to an acidic and cold environment during processing enhanced the ability of S. Enteritidis to survive in the gastric environment of the human stomach, possibly increasing the risk of a Salmonella infection after consumption of pork.

RESUMO: O objetivo deste estudo foi avaliar a resistência ao ácido de Salmonella enterica serovar Enteritidis (S. Enteritidis) previamente submetidas a tratamento ácido e inoculadas em carne suína armazenada em temperaturas de refrigeração e congelamento ao fluido gástrico simulado (FGS). As linhagens de S. Enteritidis CCS3 and ATCC 13076 previamente submetidas a tratamento ácido variando de pH 4.0 a 5.0 foram inoculadas em carne de porco e armazenadas a 4 e −18°C. A estocagem por sete dias a 4°C não afetou as populações das duas linhagens de S. Enteritidis. Após 84 dias a -18°C, as reduções médias das populações das linhagens foram de 0,8 e 1,5 ciclos logarítmicos, respectivamente. O tratamento ácido prévio não aumentou a sobrevivência das duas culturas sob baixas temperaturas. Após tratamento ácido e estocagem em temperaturas baixas, S. Enteritidis ATCC 13076 perdeu a culturabilidade após 10 minutos de desafio ao FGS. Contrariamente, S. Enteritidis CCS3 mostrou-se tolerante à exposição por três horas ao FGS. S. Enteritidis CCS3 submetidas a tratamento ácido prévio em pH 4,0 mostraram-se mais tolerantes à exposição por 180 minutos ao FGS que células submetidas aos tratamentos ácidos em pH 4,5 e 5,0 e células sem tratamento. Portanto, este estudo indica que S. Enteritidis submetida a um ambiente ácido e frio durante o processamento pode melhorar a sua capacidade de sobreviver à barreira gástrica em humanos, possivelmente, aumentando o risco de surto por Salmonella após consumo de carne de porco.

Differential expressions of surface-associated proteins of streptococcus mutans strains isolated from clinical samples under acid condition / 天津医药

Objective To investigate the changes in the surface-associated protein expression of streptococcus rnutans (Sm) isolated from clinical samples at pH7.0 and pH5.0. Methods The proteins were extracted from cells at pH7.0 and pH5.0 by Homer method. The proteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional gel electrophoresis followed by image analysis. Proteins were identified by matrix-assisted la?ser desorption ionization time of flight mass spectrometry and computer-assisted protein sequence analysis. Results Image analysis revealed that four high expression levels of protein loci and two specific protein loci were existed in two strains at pH7.0. Two high expression levels of protein loci and two specific protein loci were existed in two strains at pH 5.0. Three high expression levels of protein loci and six specific protein loci were existed in Sm593 at pH5.0. Two-component system histidine kinases Lyts and glyceraldehyde-3-phosphate dehydrogenase were highly modulated, and NADH oxidase were modulated specifically. Conclusion The two clinical isolations in acid have high expression of some special proteins, which are presumed to be the resemblance of acid reaction.The difference of protein expression of two clinical isolations in acid may represent their distinct acid resistance.

The effects of fluoride toothpaste and fluoride varnish on enamel remineralization and acid resistance:An in vitro study / 实用口腔医学杂志

Objective:To investigate the ability of fluoride toothpaste and fluoride varnish on enamel remineralization and acid resist-ance.Methods:Enamel specimens were prepared from bovine incisors,and were randomly divided into 4 groups(n=3)after acid-etching by 37%phosphoric acid.Specimens in group A(control)was processed daily with normal saline;those in group B and C were treated once with Duraphat varnish and Fluor Protector varnish respectively;in group D was daily processed with fluoride toothpaste. All specimens were incubated in artificial saliva for 2 weeks.Then all specimens received acid-etching again.Micro-hardness test, SEM observation and image analysis were performed before and after each step.Results:After 2 weeks of processing,no remineraliza-tion was found in group A.Varnish layers were observed on the surface of specimens in group B and C.In group D remineralization was detected on the enamel surface.After re-etching,micro-hardness decreased in group A and D.Fluoride varnish layers in group B and C showed strong resistance to acid-etching.After re-etching,area of micro-holes in group A and D increased(P<0.05 ),but that in group D was smaller than in the control(P<0.05).No micro-hole was observed in group B and group C.Conclusion:Protec-tive layer formed on the enamel surface by fluoride varnish is resistant to acid-etching and promotes enamel remineralization.Fluoride toothpaste application can promote enamel remineralization,but with less resistance to acid.

Helicobacter pylori Urease Activity is Influenced by Ferric Uptake Regulator

PURPOSE: The role of the Ferric Uptake Regulator (FUR) in the acid resistance of Helicobacter pylori (H. pylori) has been thought to be independent of urease. However, we demonstrated in this study that Fur influences urease activity. MATERIALS AND METHODS: A fur knockout mutant of H. pylori was constructed by replacing the Fur gene with a kanamycin resistant marker gene. The wild-type H. pylori and fur mutant were compared for survival. The integrity of the inner membrane of the bacteria was evaluated by confocal microscopy using membrane-permeant and -impermeant fluorescent DNA probes. Urease activity of intact H. pylori was measured between pH 3 and 8. Real time PCR of both strains was performed for urease genes including ureI, ureE, ureF, ureG, and ureH. RESULTS: The fur deletion affected the survival of H. pylori at pH 4. The urease activity curve of the intact fur mutant showed the same shape as the wild-type but was 3-fold lower than the wild-type at a pH of less than 5. Real time PCR revealed that the expression of all genes was consistently down-regulated in the fur mutant. CONCLUSION: The results of this study showed that fur appears to be involved in acid resistant H. pylori urease activity.

Effects of LuxS gene deletion on the acid resistance ability of Streptococcus mutans / 实用口腔医学杂志

Objective: To study the difference between the acid resistance of Streptococcus mulans Ingbritt C international standard strain and the acid resistance of LuxS mutant strain. Methods: Solutions of Streptococcus mulans standard strain and LuxS mutant strain with same density were prepared and cultured at pH 3. 5 to 7. 0 BH1 liquid for same period. Terminal growth situation was compared. After being acidized in pH 5.5 BHI liquid, the two strains were cultured at pH 3.0 BHI liquid. The acid tolerance responses of the two strains were compared. Results; (DAt pH 6.0 to 7. 0, the difference of growth between Streptococcus mulans standard strain and LuxS mutant strain was not significant at the same pH value, and the differences of bacterial growth situation under three different pH values were not significant. (1)At pH 4.5 to 5.5, the difference of growth between the two strains was significant. (2)At pH 3.0,the survival rate of LuxS mutant strain(0.006 5% )was significantly lower than the standard strain (0.078% ). (3)At pH 5.5, the survival rate of LuxS mutant strain(0.747% ) was lower than the standard strain(8.65% )by about 10 times after the pre-acidification. Conclusion; (4)At sub-lethal pH value, there is significant difference of aciduricity between Streptococcus mu-tans standard strain and LuxS mutant strain. The acid resistance of standard strain is stronger than that of LuxS mutant strain. The two strains both display the capability of acid tolerance responses. LuxS mutant strain is more sensitive to acid inactivation, but the capability of acid tolerance responses still exists.

Gene gyrA Mutation in Nalidixic acid-resistant Salmonella paratyphi A / 中华医院感染学杂志

OBJECTIVE To explore the gene gyrA mutation in nalidixic acid-resistant Salmonella paratyphi A(SPA) in Shaoxing area.METHODS Fifty-two strains of SPA gene were assessed by amplification and purification and the PCR products were detected by two directional sequencing methods.The sequences of DNA gyrase A were compared and analyzed with the OMIGA2.0 software,and the gene gyrA mutation was identified.RESULTS The mutation in nalidixic acid-resistant SPA was discovered in No.83 or No.87 animo acid site of gyrA quinolones resistant determinate region(QRDR),and the mutation of 51 strains occurred in No.83 site,1 strain occurred in No.87 site.The simultaneous mutation of two sites was not discovered,No mutations were found in other sites of gyrA QRDR.CONCLUSIONS No.83 site mutations of gene gyrA has a direct relation to nalidixic acid-resistant SPA.No.87 site mutation of gene gyrA might also cause nalidixic acid-resistantce.The nalidixic acid-resistant SPA is mainly mutated in No.83 site by TCC→TTC(Ser→Phe) in Shaoxing area.

Molecular Epidemiology of Nalidixic Acid Resistance in Shigella sonnei Isolates

Twenty-six nalidixic acid-resistant Shigella sonnei strains isolated from 1982 to 2001 and 56 nalidixic acid-resistant mutants induced by quinolone drugs from susceptible wild strains were analyzed by sequencing the gyrA gene. All the 22 nalidixic acid-resistant isolates from 1998 to 2001 showed identical amino acid substitution of Ser to Leu (TCG --> TTG) at codon 83 while 7 different mutation types were detected in artificially induced nalidixic acid-resistant mutants. Asp87 (GGC) type was observed most commonly among mutants induced by nalidixic acid while Ser83 (TTG) type was common among mutants induced by ciprofloxacin or norfloxacin. All the isolates collected between 1998 and 2001 showed identical or nearly identical pulsed-field gel electrophoresis pattern. These results suggest that the explosive increase of S. sonnei infection after 1998 was mainly due to the spread of restricted number of clones resistant to nalidixic acid.

The effects of Er,Cr:YSGG laser combined with NaF treatment on the acid resistance of human dental hard tissue / 实用口腔医学杂志

Objective:To evaluate the effects of Er,Cr:YSGG laser combined with NaF treatment on the acid resistance of human dental hard tissue.Methods:The enamel or dentin samples were randomly divided into four groups and prepared by different methods as follows: ①without treatment(control group),②laser irradiation(Laser group),③ treated with 20 g/L NaF solution(NaF group),④laser irradiation+ NaF solution treatment(Laser and NaF group).The samples of each group were respectively demineralized in 0.1 mol/L of lactic acid for 24 h and the calcium ion in the demineralization solution in each group was measured by atomic absorption spectrophotometry.The fluoride on the surface of the samples was examined by SED-X and the ultrastructure was investigated by SEM.Results:The concentrations of Ca~(2+) dissolved from the enamel or dentin samples in NaF,laser and NaF and laser groups were significantly lower than that in the control group(P(0.05)).Only in the NaF group,the F peak appeared.SEM observation showed the lased surface showed various patterns of microirregulation with a scaly appearance,the openings of dentinal tubules were visible,but no melting or carbonization;there were lot of particles attached to the surface of NaF treated samples;the ultrastructure of the NaF and laser-treated sample surfaces was similar to that of the laser treated.Conclusion:The combined use of laser and NaF dose not have synergetic effects on acid resistance of human dental hard tissue.

The effect of Nd:YAG laser irradiation combined with acidulated phosphate fluorid treatment on the acid resistance of human enamel / 实用口腔医学杂志

Objective: To study the effect of pulsed Nd:YAG laser irradiation combined with acidulated phosphate fluorid (APF) on the acid resistance of human dental enamel. Methods: Enamel samples were prepared from 192 caries-free extracted teeth. The smooth surface and pits and fissures were treated with 12 3 g/L APF for 4 minutes after 100,150 or 200 mJ pulsed Nd:YAG laser irradiation. Then the teeth were put into 12.3 g/L of artificial caries inducing solution (acid solution) for 1,5,10 or 24 h respectively. The control teeth were treated with APF only. The amount of calcium dissolved in the solution was determined with an atomic absorption spectrophotometer and the depth of artificial caries was measured with polarized microscope. Results: The amount of calcium dissolved in the acid solution was significantly less in the groups with laser treatment than that in those without laser treatment (P

The effect of initiator on pulsed Nd:YAG laser in the acid resistance of human teeth in vitro / 实用口腔医学杂志

Objective:To investigate the effect of initiator on pulsed Nd:YAG laser in the acid resistance of human teeth in vitro. Methods:A total of 25 enamel-samples and 25 dentine-samples were divided into laser plus initiator (a layer of Beijing black ink) group and laser only group.Each of the two groups was divided into five subgroups.The samples in the 5 subgroups were irritated by Na:YAG laser with an energy(J/cm2) of 0,20,30,40 and 50 respectively. Then all samples were immersed in 0.1 mol/L lactic acid demineralization solutions(pH 4.5) for 48 h at 37 ℃. The concentration of Ca 2+ (?10 -6 g) dissolved in the solution was measured by the calcium selective electrode. Results:Laser of 20-50 J/cm2 decreased the Ca 2+ concerntration in demineralization solution(P0.05).The initiator plus laser of 30-40 J/cm2 decreased the Ca 2+ release of dentine samples than laser only group (P

The effect of laser irradiaton on the acid resistance of smooth surface of human enamel / 实用口腔医学杂志

0.05 ) respectively. Before and after irradiation in the group of 100 mJ, the ratio of G 2+ /P 2+ was 1.667?0.128 and 2.135?0.156( P 0.05 ). Conclusion: The normal pulsed Nd:YAG laser irradiation alone can not increase acid residence of the enamel.

An experimental study of the effect of pulsed Nd∶YAG laser plus NaF solution on the acid resistance of human dental enamel and dentin in vitro / 第三军医大学学报

Objective To investigate the effects of pulsed Nd∶YAG laser combined with NaF solution on acid resistance of human dental enamel and dentin in vitro Methods A total of 20 enamel samples and 20 dentin samples were treated with both laser plus NaF, laser only, NaF only, or no treatment(control) Then all samples were immersed in lactic acid demineralization solution(pH 4 5) for 48 h at 37 ℃ The concentration of Ca 2+ (?10 -6 g) dissolved in the solution was measured by atomic absorption spectrophotometry Results In both enamel and dentin samples, the lowest mean Ca 2+ concentration was recorded in laser plus NaF treated group (62 055?5 879,137 474?4 444)?10 -6 g The control samples showed the highest mean of Ca 2+ concentration (143 760?5 443 and 182 726?16 115)?10 -6 g The mean Ca 2+ concentration in laser plus NaF - or NaF - or laser treated group decreased significantly as compared with that in the control( P