Investigations into the potential anticancer activity of Maximin H5

Here we report the first major example of anionic amphibian host defence peptides (HDPs) with anticancer activity. Maximin H5 is a C-terminally amidated, anionic host defence peptide (MH5N) from toads of the Bombina genus, which was shown to possess activity against the glioma cell line, T98G (EC50 = 125 μM). The peptide adopted high levels of α-helical structure (57.3%) in the presence of model cancer membranes (DMPC:DMPS in a molar ratio of 10:1). MH5N also showed a strong ability to penetrate these model membranes (Π = 10.5 mN m-1), which correlated with levels of DMPS (R2 > 0.98). Taken with the high ability of the peptide to lyse these membranes (65.7%), it is proposed that maximin H5 kills cancer cells via membranolytic mechanisms that are promoted by anionic lipid. It was also found that C-terminally deaminated maximin H5 (MH5C) exhibited lower levels of α-helical structure in the presence of cancer membrane mimics (44.8%) along with a reduced ability to penetrate these membranes (Π = 8.1 mN m-1) and induce their lysis (56.6%). These data suggested that the two terminal amide groups of native maximin H5 are required for its optimal membranolytic and anticancer activity

The effect of amidation on the behaviour of antimicrobial peptides

Aurein 2.6-COOH and aurein 3.1-COOH were studied along with their naturally occurring C-terminally amidated analogues. Circular dichroism (CD) and molecular dynamic (MD) simulations were used to study the effects of amidation on the interaction of antimicrobial peptides (AMPs) with lipid bilayers. CD measurements and MD analysis suggested that both peptide analogues were predominantly random coil and adopted low levels of α-helical structure in solution (<30 %) and in the presence of a lipid bilayer the peptides formed a stable α-helical structure. In general, amidated analogues have a greater propensity than the non-amidated peptides to form a α-helical structure. MD simulations predicted that aurein 2.6-COOH and aurein 3.1-CHOOH destabilised lipid bilayers from 1,2-dimyristoyl-sn-glycero-3-phosphocholine and 1,2-dimyristoyl-sn-glycero-3-phosphoserine via angled bilayer penetration. They also showed that aurein 2.6-CONH2 and aurein 3.1-CONH2 formed a helix horizontal to the plane of an asymmetric interfac

An atlas of anionic antimicrobial peptides from amphibians

Anionic antimicrobial peptides (AAMPs) with net charges ranging from -1 to -8 have been identified in frogs, toads, newts and salamanders across Africa, South America and China. Most of these peptides show antibacterial activity and a number of them are multifunctional, variously showing antifungal activity, anticancer action, neuropeptide function and the ability to potentiate conventional antibiotics. Antimicrobial mechanisms proposed for these AAMPs, include toroidal pore formation and the Shai-Huang-Matsazuki model of membrane interaction along with pH dependent amyloidogenesis and membranolysis via tilted peptide formation. The potential for therapeutic and biotechnical application of these AAMPs has been demonstrated, including the development of amyloid-based nanomaterials and antiviral agents. It is concluded that amphibian AAMPs represent an untapped potential source of biologically active agents and merit far greater research interest

Bovine Serum Albumin Adsorbed PGA-co-PDL Nanocarriers for Vaccine Delivery via Dry Powder Inhalation

PURPOSE: Dry powder vaccine delivery via the pulmonary route has gained significant attention as an alternate route to parenteral delivery. In this study, we investigated bovine serum albumin (BSA) adsorbed poly(glycerol adipate-co-ω-pentadecalactone), PGA-co-PDL polymeric nanoparticles (NPs) within L-leucine (L-leu) microcarriers for dry powder inhalation. METHODS: NPs were prepared by oil-in-water single emulsion-solvent evaporation and particle size optimised using Taguchi’s design of experiment. BSA was adsorbed onto NPs at different ratios at room temperature. The NPs were spray-dried in aqueous suspension of L-leu (1:1.5) using a Büchi-290 mini-spray dryer. The resultant nanocomposite microparticles (NCMPs) were characterised for toxicity (MTT assay), aerosolization (Next Generation Impactor), in vitro release study and BSA was characterized using SDS-PAGE and CD respectively. RESULTSL NPs of size 128.50 ± 6.57 nm, PDI 0.07 ± 0.03 suitable for targeting lung dendritic cells were produced. BSA adsorption for 1 h resulted in 10.23 ± 1.87 μg of protein per mg of NPs. Spray-drying with L-leu resulted in NCMPs with 42.35 ± 3.17% yield. In vitro release study at 37°C showed an initial burst release of 30.15 ± 2.33% with 95.15 ± 1.08% over 48 h. Aerosolization studies indicated fine particle fraction (FPF%) dae < 4.46 μm as 76.95 ± 5.61% and mass median aerodynamic diameter (MMAD) of 1.21 ± 0.67 μm. The cell viability was 87.01 ± 14.11% (A549 cell line) and 106.04 ± 21.14% (16HBE14o- cell line) with L-leu based NCMPs at 1.25 mg/ml concentration after 24 h treatment. The SDS-PAGE and CD confirmed the primary and secondary structure of the released BSA. CONCLUSIONS: The results suggest that PGA-co-PDL/L-leu NCMPs may be a promising carrier for pulmonary vaccine delivery due to excellent BSA adsorption and aerosolization behaviour

Bovine serum albumin adsorbed PGA-CO-PDL nanocarriers for vaccine delivery via dry powder inhalation

Purpose: Dry powder vaccine delivery via the pulmonary route has gained significant attention as an alternate route to parenteral delivery. In this study, we investigated bovine serum albumin (BSA) adsorbed poly(glycerol adipate-co-ω-pentadecalactone), PGA-co-PDL polymeric nanoparticles (NPs) within L-leucine (L-leu) microcarriers for dry powder inhalation. Methods: NPs were prepared by oil-in-water single emulsion-solvent evaporation and particle size optimised using Taguchi's design of experiment. BSA was adsorbed onto NPs at different ratios at room temperature. The NPs were spray-dried in aqueous suspension of L-leu (1:1.5) using a Büchi-290 mini-spray dryer. The resultant nanocomposite microparticles (NCMPs) were characterised for toxicity (MTT assay), aerosolization (Next Generation Impactor), in vitro release study and BSA was characterized using SDS-PAGE and CD respectively. Results: NPs of size 128.50∈±∈6.57 nm, PDI 0.07∈±∈0.03 suitable for targeting lung dendritic cells were produced. BSA adsorption for 1 h resulted in 10.23∈±∈1.87 μg of protein per mg of NPs. Spray-drying with L-leu resulted in NCMPs with 42.35∈±∈3.17% yield. In vitro release study at 37°C showed an initial burst release of 30.15∈±∈2.33% with 95.15∈±∈1.08% over 48 h. Aerosolization studies indicated fine particle fraction (FPF%) dae∈<∈4.46 μm as 76.95∈±∈5.61% and mass median aerodynamic diameter (MMAD) of 1.21∈±∈0.67 μm. The cell viability was 87.01∈±∈14.11% (A549 cell line) and 106.04∈±∈21.14% (16HBE14o- cell line) with L-leu based NCMPs at 1.25 mg/ml concentration after 24 h treatment. The SDS-PAGE and CD confirmed the primary and secondary structure of the released BSA. Conclusions: The results suggest that PGA-co-PDL/L-leu NCMPs may be a promising carrier for pulmonary vaccine delivery due to excellent BSA adsorption and aerosolization behaviour

Dry powder pulmonary delivery of cationic PGA-co-PDL nanoparticles with surface adsorbed model protein.

Pulmonary delivery of macromolecules has been the focus of attention as an alternate route of delivery with benefits such as; large surface area, thin alveolar epithelium, rapid absorption and extensive vasculature. In this study, a model protein, bovine serum albumin (BSA) was adsorbed onto cationic PGA-co-PDL polymeric nanoparticles (NPs) prepared by a single emulsion solvent evaporation method using a cationic surfactant didodecyldimethylammonium bromide (DMAB) at 2% w/w (particle size: 128.64±06.01nm and zeta-potential: +42.32±02.70mV). The optimum cationic NPs were then surface adsorbed with BSA, NP:BSA (100:4) ratio yielded 10.01±1.19μg of BSA per mg of NPs. The BSA adsorbed NPs (5mg/ml) were then spray-dried in an aqueous suspension of L-leucine (7.5mg/ml, corresponding to a ratio of 1:1.5/NP:l-leu) using a Büchi-290 mini-spray dryer to produce nanocomposite microparticles (NCMPs) containing cationic NPs. The aerosol properties showed a fine particle fraction (FPF, dae<4.46μm) of 70.67±4.07% and mass median aerodynamic diameter (MMAD) of 2.80±0.21μm suggesting a deposition in the respiratory bronchiolar region of the lungs.The cell viability was 75.76±03.55% (A549 cell line) at 156.25μg/ml concentration after 24h exposure. SDS-PAGE and circular dichroism (CD) confirmed that the primary and secondary structure of the released BSA was maintained. Moreover, the released BSA showed 78.76±1.54% relative esterolytic activity compared to standard BSA

Linearized esculentin-2EM shows pH dependent antibacterial activity with an alkaline optimum

Here the hypothesis that linearized esculentin 2EM (E2EM-lin) from Glandirana emeljanovi possesses pH dependent activity is investigated. The peptide showed weak activity against Gram-negative bacteria (MLCs ≥ 75.0 μM) but potent efficacy towards Gram-positive bacteria (MLCs ≤ 6.25 μM). E2EM-lin adopted an α-helical structure in the presence of bacterial membranes that increased as pH was increased from 6 to 8 (↑ 15.5 to 26.9 %), while similar increases in pH enhanced the ability of the peptide to penetrate (↑ 2.3 to 5.1 mN m-1) and lyse (↑ 15.1 to 32.5%) these membranes. Theoretical analysis predicted that this membranolytic mechanism involved a tilted segment, that increased along the α-helical long axis of E2EM-lin (1-23) in the N → C direction, with - increasing overall from circa - 0.8 to - 0.3. In combination, these data showed that E2EM-lin killed bacteria via novel mechanisms that were enhanced by alkaline conditions and involved the formation of tilted and membranolytic, α-helical structure. The preference of E2EM-lin for Gram-positive bacteria over Gram-negative organisms was primarily driven by the superior ability of phosphatidylglycerol to induce α-helical structure in the peptide as compared to phosphatidylethanolamine. These data were used to generate a novel pore-forming model for the membranolytic activity of E2EM-lin, which would appear to be the first, major reported instance of pH dependent AMPs with alkaline optima using tilted structure to drive a pore-forming process. It is proposed that E2EM-lin has the potential for development to serve purposes ranging from therapeutic usage, such as chronic wound disinfection, to food preservation by killing food spoilage organisms

The influence of institutional factors on corporate narratives: a thematic content analysis of Guinness

This paper provides a thematic content analysis of the Chairman’s Statement of Arthur Guinness & Son Ltd over time. The analysis traces the evolution of the content over four distinct periods using a coding scheme developed from extant research. The objective is to study whether the corporate narratives change in line with the institutional factors over time. To interpret the results, we draw on an institutional theory-based lens to offer potential explanations of some of the change and stability noted. Institutions can constrain behaviour, but they can also support and empower agents to bring about change. The results of the longitudinal content analysis reveals some variations over time, but in general the content is relatively stable. This may be explained by the organisation itself being an institution that is sufficiently institutionalised so that corporate reporting remained relatively stable. This suggests Guinness may be an example of a strong institution over time. "The final, definitive version of this paper has been published in Accounting History, 2020, 25(3), 425-447, published by SAGE Publishing. Available online: https://doi.org/10.1177/1032373219881811. DOI: 10.1177/1032373219881811. Please cite the published version.

Safety of bazedoxifene in a randomized, double-blind, placebo- and active-controlled phase 3 study of postmenopausal women with osteoporosis

Background. We report the safety findings from a 3-year phase 3 study (NCT00205777) of bazedoxifene, a novel selective estrogen receptor modulator under development for the prevention and treatment of postmenopausal osteoporosis. Methods. Healthy postmenopausal osteoporotic women (N = 7,492; mean age, 66.4 years) were randomized to daily doses of bazedoxifene 20 or 40 mg, raloxifene 60 mg, or placebo for 3 years. Safety and tolerability were assessed by adverse event (AE) reporting and routine physical, gynecologic, and breast examination. Results. Overall, the incidence of AEs, serious AEs, and discontinuations due to AEs in the bazedoxifene groups was not different from that seen in the placebo group. The incidence of hot flushes and leg cramps was higher with bazedoxifene or raloxifene compared with placebo. The rates of cardiac disorders and cerebrovascular events were low and evenly distributed among groups. Venous thromboembolic events, primarily deep vein thromboses, were more frequently reported in the active treatment groups compared with the placebo group; rates were similar with bazedoxifene and raloxifene. Bazedoxifene showed a neutral effect on the breast and an excellent endometrial safety profile. The incidence of fibrocystic breast disease was lower with bazedoxifene 20 and 40 mg versus raloxifene or placebo. Reductions in total and low-density lipoprotein levels and increases in high-density lipoprotein levels were seen with bazedoxifene versus placebo; similar results were seen with raloxifene. Triglyceride levels were similar among groups. Conclusion. Bazedoxifene showed a favorable safety and tolerability profile in women with postmenopausal osteoporosis. © 2010 Christiansen et al; licensee BioMed Central Ltd.link_to_subscribed_fulltex