33 research outputs found

    Preparation of Colon-Targeted Acetylharpagide Tablets and its Release Properties in vivo and in vitro

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    Ethno Pharmacological Relevance: Acetylharpagide is a monomeric compound extracted from Ajuga decumbens, widely used for remedying infectious and inflammatory diseases in Southern China.Aim of the Study: The present study designed and investigated the formulation of colon-targeted acetylharpagide tablets according to the dual controlled release mechanisms of time-delay and pH-sensitivity.Materials and Methods: The core tablets of acetylharpagide were coated with the material used in time-delay systems such as ethyl cellulose and suitable channeling agent, followed by pH-dependent polymers, polyacrylic resin II and III in a combination of 1:4. Furthermore, the release and absorption performance of colon-targets tables were evaluated in vitro and in vivo. In the in vitro tests, the optimized formulation was not released in simulated gastric fluid in 2 h; the release was <5% at pH 6.8 simulated intestinal fluids for 4 h; the drug was completely released within 5 h at pH 7.6 simulated colon fluid. In the in vivo tests, pharmacokinetic characteristics of the colon-targeted tablets were investigated in dogs.Results: The results indicated that the acetylharpagide tablets with the technology of colon-targeting caused delayed Tmax, prolonged absorption time, lower Cmax, and AUCINF_obs. Meanwhile, the apparent volume of distribution (Vz_F_bs) of the colon-target tablets was higher than the reference.Conclusions: These results suggested that colon-targeted acetylharpagide tablets deliver the drug to the colon. The in vitro performance of colon-targeted acetylharpagide tablet was appropriately correlated with its performance in vivo

    FAK Mediates a Compensatory Survival Signal Parallel to PI3K-AKT in PTEN-Null T-ALL Cells

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    SummaryMutations and inactivation of phosphatase and tensin homolog deleted from chromosome 10 (PTEN) are observed in 15%–25% of cases of human T cell acute lymphoblastic leukemia (T-ALL). Pten deletion induces myeloproliferative disorders (MPDs), acute myeloid leukemia (AML), and/or T-ALL in mice. Previous studies attributed Pten-loss-related hematopoietic defects and leukemogenesis to excessive activation of phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR signaling. Although inhibition of this signal dramatically suppresses the growth of PTEN-null T-ALL cells in vitro, treatment with inhibitors of this pathway does not cause a complete remission in vivo. Here, we report that focal adhesion kinase (Fak), a protein substrate of Pten, also contributes to T-ALL development in Pten-null mice. Inactivation of the FAK signaling pathway by either genetic or pharmacologic methods significantly sensitizes both murine and human PTEN-null T-ALL cells to PI3K/AKT/mTOR inhibition when cultured in vitro on feeder layer cells or a matrix and in vivo

    Cathelicidin-BF, a Snake Cathelicidin-Derived Antimicrobial Peptide, Could Be an Excellent Therapeutic Agent for Acne Vulgaris

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    Cathelicidins are a family of antimicrobial peptides acting as multifunctional effector molecules in innate immunity. Cathelicidin-BF has been purified from the snake venoms of Bungarus fasciatus and it is the first identified cathelicidin antimicrobial peptide in reptiles. In this study, cathelicidin-BF was found exerting strong antibacterial activities against Propionibacterium acnes. Its minimal inhibitory concentration against two strains of P. acnes was 4.7 µg/ml. Cathelicidin-BF also effectively killed other microorganisms including Staphylococcus epidermidis, which was possible pathogen for acne vulgaris. Cathelicidin-BF significantly inhibited pro-inflammatory factors secretion in human monocytic cells and P. acnes-induced O2.− production of human HaCaT keratinocyte cells. Observed by scanning electron microscopy, the surfaces of the treated pathogens underwent obvious morphological changes compared with the untreated controls, suggesting that this antimicrobial peptide exerts its action by disrupting membranes of microorganisms. The efficacy of cathelicidin-BF gel topical administering was evaluated in experimental mice skin colonization model. In vivo anti-inflammatory effects of cathelicidin-BF were confirmed by relieving P. acnes-induced mice ear swelling and granulomatous inflammation. The anti-inflammatory effects combined with potent antimicrobial activities and O2.− production inhibition activities of cathelicidin-BF indicate its potential as a novel therapeutic option for acne vulgaris

    N-Terminus-Mediated Degradation of ACS7 Is Negatively Regulated by Senescence Signaling to Allow Optimal Ethylene Production during Leaf Development in Arabidopsis

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    Senescence is the final phase of leaf development, characterized by key processes by which resources trapped in deteriorating leaves are degraded and recycled to sustain the growth of newly formed organs. As the gaseous hormone ethylene exerts a profound effect on the progression of leaf senescence, both the optimal timing and amount of its biosynthesis are essential for controlled leaf development. The rate-limiting enzyme that controls ethylene synthesis in higher plants is ACC synthase (ACS). In this study, we evaluated the production of ethylene and revealed an up-regulation of ACS7 during leaf senescence in Arabidopsis. We further showed that the promoter activity of ACS7 was maintained at a relatively high level throughout the whole rosette development process. However, the accumulation level of ACS7 protein was extremely low in the light-grown young seedlings, and it was gradually restored as plants aging. We previously demonstrated that degradation of ACS7 is regulated by its first 14 N-terminal residues, here we compared the phenotypes of transgenic Arabidopsis overexpressing a truncated ACS7 lacking the 14 residues with transgenic plants overexpressing the full-length protein. Results showed that seedlings overexpressing the truncated ACS7 exhibited a senescence phenotype much earlier than their counterparts overexpressing the full-length gene. Fusion of the 14 residues to SSPP, a PP2C-type senescence-suppressed protein phosphatase, effectively rescued the SSPP-induced suppression of rosette growth and development but had no effect on the delayed senescence. This observation further supported that N-terminus-mediated degradation of ACS7 is negatively regulated by leaf senescence signaling. All results of this study therefore suggest that ACS7 is one of the major contributors to the synthesis of ‘senescence ethylene’. And more importantly, the N-terminal 14 residue-mediated degradation of this protein is highly regulated by senescence signaling to enable plants to produce the appropriate levels of ethylene required

    Effects of 0.2% cathelicidin-BF and clindamycin gel on <i>P. acnes</i>-induced inflammation and <i>P. acnes</i> growth <i>in vivo</i>.

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    <p>Left ears of mice were intradermally injected with <i>P. acnes</i> (1×10<sup>7</sup> CFU per 20 µl in PBS) to induce inflammation. Right ears of the same mice were injected with 20 µl of 0.9% salt water (vehicle). Subsequently, 0.2% cathelicidin-BF gel, 0.2% clindamycin gel or vehicle was applied on the ear skin surface of mice. (<b>A</b>) The increase in ear thickness was measured using a micro caliper before and 24 hours after the bacterial injection. (<b>B</b>) 24 hours after P. acnes injection, CFUs of P. acnes in the ear were enumerated as described in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0022120#s4" target="_blank">Materials and methods</a>” section. Data represent mean ± SE of five individual experiments. Cath: cathelicidin-BF; CL: clindamycin. The values for cathelicidin-BF and clindamycin were significant different from the value for the vehicle (*<i>P</i><0.05 and **<i>p</i><0.01).</p

    Effects of cathelicidin-BF and clindamycin on cytokine production by <i>P. acnes</i>-stimulated monocytic cells.

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    <p>Human monocytic THP-1 cells (1×10<sup>6</sup> cells/ml) were incubated with heat-killed (incubated at 80°C for 30 min to kill the bacteria) <i>P. acnes</i> (wet weight 100 µg/ml) alone or in combination with different concentrations (0.01, 0.05, and 0.1 mg/ml) of tested sample for 18 h. These represent mean values of three independent experiments. The values for cathelicidin-BF and clindamycin were significant different from the value for the HPC group (*<i>P</i><0.05 and **<i>p</i><0.01). NC: Negative control; HPC: heat-killed <i>P. acnes</i>; CA: cathelicidin-BF; CL: clindamycin.</p
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