Double-blind comparison of absorbable colloidal bismuth subcitrate and nonabsorbable bismuth subnitrate in the eradication of Helicobacter pylori and the relief of nonulcer dyspepsia

Background. Bismuth is widely used for the eradication of H. pylori , especially in developing countries, although there are concerns over its neurotoxicity. Whether bismuth has to be absorbed in humans to act against H. pylori is not known. In this study, we compared "absorbable" (colloidal bismuth subcitrate) and "nonabsorbable" (bismuth subnitrate) bismuth as part of triple therapy in the eradication of H. pylori.
Materials and Methods. A double-blind, randomized, placebo-controlled trial was carried out with 120 H. pylori –positive patients with nonulcer dyspepsia. Group CBS + Ab (n = 35) received colloidal bismuth subcitrate (one tablet qds), amoxicillin (500 mg qds), and metronidazole (400 mg tds). Group BSN + Ab (n = 35) received bismuth subnitrate (two tablets tds) and the same antibiotics. Group Ab (n = 35) received placebo bismuth (two tablets tds) and the antibiotics. Group BSN (n = 15) received bismuth subnitrate (two tablets tds) and placebo antibiotics. Bismuth was taken for 4 weeks and the antibiotics for the first 2 weeks. H. pylori eradication, side effects, compliance, pre- and post-treatment symptom scores, and bismuth absorption were assessed.
Results. H. pylori eradication was 69%, 83%, 31%, and 0% in CBS + Ab, BSN + Ab, Ab, and BSN, respectively. Side effects, compliance, and symptom relief were similar in all groups, but blood bismuth levels were significantly greater in CBS + Ab than the other three groups.
Conclusion. The efficacy of bismuth-based therapies as part of triple therapy in the eradication of H. pylori is unrelated to absorption. Hence, the use of effective but poorly absorbed bismuth preparations should be encouraged for bismuth-based eradication therapies.     

In vitro evaluation of Bacopa monniera on anti-Helicobacter pylori activity and accumulation of prostaglandins.

Bacopa monniera is an Indian tratidional medicine widely used to improve intellectual functions. Earlier, we had reported the prophylactic and curative effects of standardized extract of Bacopa monniera (BME) in various gastric ulcer models. The effect was due to augmentation of the defensive mucosal factors like increase in mucin secretion, life span of mucosal cells and gastric antioxidant effect rather than on the offensive acid-pepsin secretion. The present study includes evaluation of standardized BME (bacoside A content--35.5 +/- 0.9) on other contributing factors towards ulcerogenesis. BME in the dose of 1000 microg/ml showed anti-Helicobacter pylori activity in vitrol and in the dose of 10 microg/ml increased in vitro of prostanoids (PGE and PGI2) in human colonic mucosal incubates. It may be concluded that these factors may contribute to antiulcerogenic activity of BME.     

Synthesis and in vitro selective anti-Helicobacter pylori activity of pyrazoline derivatives

In order to develop new anti-Helicobacter pylori agents, a series of N1-substituted 3,5-diphenyl pyrazolines P1-P13 was prepared and evaluated for their antibacterial activity. All synthesized compounds showed little or no activity against different species of Gram-positive and Gram-negative bacteria of clinical relevance and against various strains of pathogenic fungi. The same derivatives exhibited a significant degree of activity against a range of H. pylori strains, including those resistant to the reference compound metronidazole. Among the prepared compounds those with an N1-acetyl group and a 4-methoxy substituent in the 5-phenyl ring showed the best activity against H. pylori metronidazole resistant strains in the 1-4 microg/mL MIC range.     

Synthesis and anti-Helicobacter pylori activity of FR182024, a new cephem derivative

The synthesis and anti-Helicobacter pylori activity of a novel cephem derivative FR182024 (1) are described. FR182024 having a (5-methyl-1,3,4-thiadiazol-2-yl)-thio moiety at the 3-position and a phenylacetamido at the 7-position was found to have extremely potent in vitro anti-H.pylori activity, superior therapeutic efficacy to AMPC and CAM, and low potential for causing diarrhea.     

In vitro embryotoxicity of a series of para-substituted phenols: structure, activity, and correlation with in vivo data.

The embryotoxicity of phenol and twelve para-substituted congeners on mid-gestation rat embryos was evaluated in vitro. Through application of correlative procedures and stepwise regression, equations describing the relationship between physical-chemical properties and various measures of activity were developed. Embryotoxicity was quantified by the log of the reciprocal of the potency estimates for reduction in selected growth parameters and induction of four morphological defects. In general, co-cultured hepatocytes ameliorated embryotoxicity; only phenol-induced embryotoxicity was enhanced by the presence of hepatocytes. In the absence of hepatocytes, measures of growth retardation were positively correlated with molar refractivity of the phenols. With hepatocytes, lipophilicity became important for describing the potential to induce growth deficits. The structural defects had varying correlation patterns in both culture systems. Potencies of these congeners in vitro were also compared to maternal and developmental potencies observed in vivo (Kavlock, Teratology, 41:43-59, '90). Two of the congeners were very toxic in both systems. For the remaining congeners, one maternal toxicity measure was found to be positively correlated with embryotoxicity for growth and development in vitro without hepatocytes. With hepatocytes, a broad spectrum of correlations, both positive and negative, were observed between in vivo developmental toxicity endpoints and in vitro embryotoxicity. Data from preliminary dosimetry studies suggest that phenol congeners may accumulate in embryos exposed in vitro more readily than with in vivo exposure. Potency calculations based on dosimetry information may demonstrate better correlations between data and allow additional relationships between chemical structure and activity to be developed.     

Pharmacology, in vitro activity, and in vivo efficacy of new antifungal agents

Invasive fungal infections remain significant clinical challenges and are associated with high morbidity and mortality in immunocompromised patients. Despite the availability of new antifungal agents, response rates against many of these infections remain suboptimal. In addition, many of the clinically available agents have limited oral bioavailability, are associated with adverse effects due to similarities between fungal and mammalian cells, or have significant drug-drug interactions. For these reasons, there is great interest in developing new antifungal drugs, including those with novel mechanisms of action. This article reviews the pharmacology, in vitro activity, and in vivo effectiveness of new antifungal agents, including members of new classes with novel mechanisms of action and at various stages of preclinical and clinical development. These agents include the triazole isavuconazole, the echinocandin aminocandin, the histone deacetylase inhibitor MGCD290, and the sordarin derivative FR290581.     

In vitro stability and in vivo anti-inflammatory efficacy of synthetic jasmonates

A chlorinated methyl jasmonate analog (J7) was elaborated as an in vitro anti-inflammatory lead. However, its in vitro efficacy profile was not reproduced in a subsequent in vivo evaluation, presumably due to its rapid enzymatic hydrolysis in a biological system. In an attempt to improve the metabolic stability of the lead J7 by replacement of its labile methyl ester with reasonable ester groups, several analogs resistant to enzymatic hydrolysis were synthesized. In vivo evaluation of the stability-improved analogs showed that these compounds displayed higher efficacy than the lead J7, suggesting that these new jasmonate analogs may serve as potential anti-inflammatory leads.     

In vitro and in vivo antimycobacterial activity of antiinflammatory drug, diclofenac sodium

The non-steroidal antiinflammatory drug diclofenac sodium exhibited remarkable inhibitory action against both drug sensitive and drug resistant clinical isolates of Mycobacterium tuberculosis, as well as other mycobacteria. This agent was tested in vitro against 45 different strains of mycobacteria, most of which were inhibited by the drug at 10-25 microg/ml concentration. When tested in vivo, diclofenac, injected at 10 mg/kg body weight of a Swiss strain of white mice, could significantly protect them when challenged with a 50 median lethal dose of M. tuberculosis H37 Rv102. According to Chi-square test, the in vivo data were highly significant (P<0.01).     

In vitro and in vivo osteogenic activity of licochalcone A

We investigated the in vitro and in vivo osteogenic activity of licochalcone A. At low concentrations, licochalcone A stimulated the differentiation of mouse pre-osteoblastic MC3T3-E1 subclone 4 (MC4) cells and enhanced the bone morphogenetic protein (BMP)-2-induced stimulation of mouse bi-potential mesenchymal precursor C2C12 cells to commit to the osteoblast differentiation pathway. This osteogenic activity of licochalcone A was accompanied by the activation of extracellular-signal regulated kinase (ERK). The involvement of ERK was confirmed in a pharmacologic inhibition study. Additionally, noggin (a BMP antagonist) inhibited the osteogenic activity of licochalcone A in C2C12 cells. Licochalcone A also enhanced the BMP-2-stimulated expression of various BMP mRNAs. This suggested that the osteogenic action of licochalcone A in C2C12 cells could be dependent on BMP signaling and/or expression. We then tested the in vivo osteogenic activity of licochalcone A in two independent animal models. Licochalcone A accelerated the rate of skeletal development in zebrafish and enhanced woven bone formation over the periosteum of mouse calvarial bones. In summary, licochalcone A induced osteoblast differentiation with ERK activation in both MC4 and C2C12 cells and it exhibited in vivo osteogenic activity in zebrafish skeletal development and mouse calvarial bone formation. The dual action of licochalcone A in stimulating bone formation and inhibiting bone resorption, as described in a previous study, might be beneficial in treating bone-related disorders.     

In vitro oxidative activity of cupric complexes of kanamycin A in comparison to in vivo bactericidal efficacy

The interactions of copper(II) complexes of kanamycin A with oxidation-susceptible biomolecules: 2'-deoxyguanosine, plasmid DNA and yeast tRNA(Phe) were studied in both the presence and absence of hydrogen peroxide. The mixture of complex with H(2)O(2) was found to be an efficient oxidant, converting dG to its 8-oxo derivative, generating strand breaks in plasmid DNA and multiple cleavages in tRNA(Phe). Some of these reactions may play a role in toxic effects of aminoglycoside antibiotics. These complexes were screened for their antibacterial activity. The microbiological studies undertaken to compare the bactericidal action of kanamycin A alone and complexed with copper(II) ions in both neutral and oxidative environment revealed that the enhancement of bactericidal action by Cu(II) was not statistically significant.     

In vitro and in vivo inhibition of Helicobacter pylori by Lactobacillus casei strain Shirota

We studied the potential inhibitory effect of Lactobacillus casei strain Shirota (from the fermented milk product Yakult [Yakult Ltd., Tokyo, Japan]) on Helicobacter pylori by using (i) in vitro inhibition assays with H. pylori SS1 (Sydney strain 1) and nine H. pylori clinical isolates and (ii) the in vivo H. pylori SS1 mouse model of infection over a period of 9 months. In vitro activity against H. pylori SS1 and all of the clinical isolates was observed in the presence of viable L. casei strain Shirota cells but not in the cell-free culture supernatant, although there was profound inhibition of urease activity. In vivo experiments were performed by oral administration of L. casei strain Shirota in the water supply over a period of 9 months to 6-week-old C57BL/6 mice previously infected with H. pylori SS1 (study group; n = 25). Appropriate control groups of H. pylori-infected but untreated animals (n = 25) and uninfected animals given L. casei strain Shirota (n = 25) also were included in the study. H. pylori colonization and development of gastritis were assessed at 1, 2, 3, 6, and 9 months postinfection. A significant reduction in the levels of H. pylori colonization was observed in the antrum and body mucosa in vivo in the lactobacillus-treated study group, as assessed by viable cultures, compared to the levels in the H. pylori-infected control group. This reduction was accompanied by a significant decline in the associated chronic and active gastric mucosal inflammation observed at each time point throughout the observation period. A trend toward a decrease in the anti-H. pylori immunoglobulin G response was measured in the serum of the animals treated with lactobacillus, although this decrease was not significant.     

Design, synthesis, and anti-Helicobacter pylori activity of erythromycin A (E)-9-oxime ether derivatives

The synthesis and anti-Helicobacter pylori (H. pylori) activity evaluation of a new series of erythromycin A (E)-9-oxime ether derivatives are described. These compounds exhibited comparable in vitro anti-H. pylori activity and improved acid stability compared to the reference compound clarithromycin.     

In vitro and in vivo anti-Leishmania activity of polysubstituted synthetic chalcones

The in vitro screening of 43 polysubstituted chalcones against Leishmania amazonensis axenic amastigotes, led to the evaluation of 9 of them in a macrophage-infected model with the two other most infectious Leishmania species prevalent in Peru (L. braziliensis and L. peruviana). The five most active and selective chalcones were studied in vivo, resulting on the identification of two chalcones with high reduction parasite burden percentages.     

Biotinated bone morphogenetic protein-2: In vivo and in vitro activity.

Recombinant human bone morphogenetic protein-2 (rhBMP-2) was biotinated, and the bioactivity of biotinated protein was assessed in vitro (alkaline phosphate induction in limb bud cells) and in vivo (osteoinduction in the rat ectopic assay). Amino-biotinated rhBMP-2 exhibited an increase in bioactivity whereas carboxy-biotinated rhBMP-2 did not exhibit any changes in bioactivity in vitro. Avidin inhibited the bioactivity of amino-biotinated but not carboxyl-biotinated rhBMP-2. Both amino- and carboxy-modified rhBMP-2 induced bone at an equivalent level to that of unmodified rhBMP-2 in vivo. The presence of avidin did not affect the osteoinductive activity of both types of biotinated rhBMP-2. The overall results indicated that binding to a large protein, avidin, might affect rhBMP-2 activity in vitro depending on the binding site; however, in vivo activity was unaffected by the avidin binding.     

In vitro and in vivo ACTH-releasing activity of ovine CRF,sauvagine and urotensin I

The ability of three homologous peptides, ovine corticotropin-releasing factor (CRF), sauvagine and urotensin I, to release ACTH was examined in vitro and in vivo. All three peptides exhibit statistically equivalent potencies to stimulate ACTH secretion both by cultured pituitary cells and in pharmacology blocked rats. These results suggest that all three peptides evolved from a common mammalian precursor that possessed high hypophysiotropic potency.     

Synthesis,selective anti-Helicobacter pylori activity,and cytotoxicity of novel N-substituted-2-oxo-2H-1-benzopyran-3-carboxamides

N-substituted-3-carboxamido-coumarin derivatives were prepared and evaluated for selective antibacterial activity against 20 isolates of Helicobacter pylori clinical strains, including five metronidazole resistant ones. Some of them possessed the best activity against H. pylori metronidazole resistant strains with MIC values lower than the drug reference (metronidazole). Furthermore, anti-inflammatory activity through the inhibition of the IL-8 production was investigated.     

In vitro stability and ex vivo absorption of thymol monoglucosides in the porcine gut

Thymol α-D-glucopyranoside (TαG) and thymol β-D-glucopyranoside (TβG) are believed to have different kinetic behaviours in the porcine gut than its parent aglycon thymol. However, recently, it was shown that concentrations of both glucosides decreased rapidly in the stomach and proximal small intestine following oral supplementation to piglets as did thymol. Yet, the stability of thymol glucosides in gut contents and their absorption route remains obscure. Therefore, a series of in vitro incubations were performed, simulating the impact of pH, digestive enzymes, bacterial activity and mucosal extracts on stability of these glucosides. Their absorption mechanisms were investigated using the Ussing chamber model in the presence or the absence of inhibitors of sodium-dependent glucose linked transporter 1 and lactase phlorizin hydrolase. Both glucosides remained intact at physiological pH levels in the presence of digestive enzymes. Recoveries from TαG and TβG were below 90% when incubated with small intestinal homogenates from the distal jejunum or from all sampled sites, respectively. However, no aglycon could be detected in these samples. Bacterial inoculum of the small intestine, on the other hand, hydrolysed TβG quickly with up to 44% of free aglycon appearing. TαG proved more resistant to porcine gastro-intestinal bacterial glucosidases with only trace amounts (<1%) of free thymol at the end of the incubations. Electrophysiological measurements in Ussing chambers did not suggest active transport of the glucosides. Mucosal TαG and TβG concentrations were unchanged between start and end of the absorption measurements. Additionally, no TαG and only a very limited amount of TβG were retrieved from the serosal side. Tissue associated concentrations, although marginal (<1% of luminal concentration), were mainly as intact glucoside or as aglycon for TαG and TβG, respectively. Addition of both inhibitors significantly increased the amount of intact glucosides retrieved from the mucosal tissues as compared to controls. In conclusion, bacterial hydrolysis was identified as the most important source of TβG loss, whereas TαG seemed less prone to degradation or absorption in these in vitro and ex vivo models.