Bactericidal urea crown ethers target phosphatidylethanolamine membrane lipids.

An increasing number of people are infected with antibiotic-resistant bacteria each year, sometimes with fatal consequences. In this manuscript, we report a novel urea-functionalized crown ether that can bind to the bacterial lipid phosphatidylethanolamine (PE), facilitate PE flip-flop and displays antibacterial activity against the Gram-positive bacterium Bacillus cereus with a minimum inhibitory concentration comparable to that of the known PE-targeting lantibiotic duramycin.

Do Voluntary Lab-Based Active Learning Sessions Impact Medical Student Knowledge Retention?

BACKGROUND: Despite recent evidence demonstrating the benefits of case-based and active learning strategies in medical education, many medical schools have reduced or entirely eliminated teaching laboratories in medical microbiology courses. The objective of our investigation was to analyze the impact of a voluntary hands-on microbiology laboratory session on students' knowledge retention and ability to apply the underlying principles to exam questions in our Introduction to Infectious Diseases (IID) course. METHODS: We compared the performance of students participating in the wet labs with those who did not, analyzing scores on exam questions directly related to the concepts presented in the laboratory session and their overall scores on the IID module exam. The voluntary nature of our microbiology lab session provided a unique opportunity to assess its impact on knowledge retention independent of other factors, such as lecture and exam content, etc. Data were collected for 7 academic years and analyzed in aggregate. RESULTS: Students who attended voluntary lab sessions scored higher on exam questions related to lab exercises than students who did not attend (Mann-Whitney, p = 0.0074). These results support the benefit of reexamining material originally presented during classroom sessions in an active, collaborative learning environment. Course evaluation responses indicted that students valued the opportunity to visually reinforce concepts they had previously read in a textbook or heard in lectures. CONCLUSIONS: At a time when many medical schools are reducing or eliminating hands-on lab sessions in microbiology and other basic sciences, our results highlight the benefits of this teaching strategy. The laboratory session provided an opportunity for students to revisit concepts initially presented in the traditional classroom setting and to actively engage in applying these concepts to case-based scenarios. The improved educational outcomes will benefit students in future standardized exams as well as in their professional practice.

Nanoemulsions Enhance in vitro Transpapillary Diffusion of Model Fluorescent Dye Nile Red.

While the feasibility of transpapillary drug delivery has previously been established, localized transport via the mammary ducts may be improved with tailored drug delivery formulations. The objective of this study was to investigate the impact of nanoemulsion encapsulation on transpapillary delivery in vitro. Nanoemulsion formulations composed of isopropyl myristate and Tween 80 encapsulating a fluorescent dye were applied topically on porcine nipples using a Franz diffusion cell. A combination of dye extraction and fluorescence image analysis was used to quantify the total amount of dye retained within the nipple and to characterize the penetration routes. After diffusion for 6 hours, the amount of dye deposited in the nipple was proportional to the formulation's water concentration. The 90% water formulation deposited significantly more dye via both the stratum corneum and mammary ducts, while the 80% and 70% water formulations moderately increased ductal penetration, but minimally altered stratum corneum penetration as compared to the control solution. Similar trends were found after diffusion for 48 hours; however, the overall impact was diminished, likely due to the nanoemulsion's topical instability. This study indicates that drug delivery vehicles, nanoemulsions specifically, enhance delivery of encapsulated molecules via the stratum corneum and mammary ducts in a formulation-dependent basis.

Liposomes Enhance Dye Localization within the Mammary Ducts of Porcine Nipples.

Transductal and transepidermal diffusion are two distinct penetration routes of molecules administered via the nipple. To improve the therapeutic potential of this drug administration technique, drug penetration into the mammary ducts should be maximized, which may be accomplished through design optimization of drug delivery vehicles. In this study, we evaluated liposomes, ranging in size from 100 to 3000 nm, to improve ductal penetration of model fluorescent dyes using fluorescence microscopy and image analysis. Liposomes encapsulating a model fluorescent lipophilic dye, nile red, or hydrophilic dye, sulforhodamine B, were applied topically on porcine nipples for 6 h in vitro. Liposome encapsulation of sulforhodamine B significantly reduced the total amount of dye penetrating the nipple, while penetration of liposome-encapsulated nile red varied depending on vesicle size, as compared to their solution controls. However, the fluorescence intensity localized at the ductal epithelium was higher at extended nipple depths in tissues treated with liposomes versus dye solutions, suggesting a higher concentration of dye penetrating the nipple via the ducts. In contrast, the fluorescence intensity measured at the stratum corneum was reduced (sulforhodamine B) or unchanged (nile red) in nipples treated with liposomes versus dye solutions, suggesting a decrease or no change in dye penetration of the nipple via the stratum corneum. Furthermore, the limited penetration distance into the connective tissue beyond the ductal epithelium for both liposome-encapsulated nile red and sulforhodamine B suggests that liposomes remain intact over the 6 h duration of this study when penetrating through the ducts and enhance retention within the ductal lumen. However, the varied penetration profiles into the connective tissue beyond the stratum corneum between liposome-encapsulated nile red and sulforhodamine B suggests that the liposomes destabilize when penetrating the outer tissues layers of the nipple. Overall, liposomes, regardless of size, improved penetration into and retention within the mammary ducts, while limiting penetration into the stratum corneum, indicating their capacity to target the mammary ductal network.

Evaluation of Amphiphilic Star/Linear-Dendritic Polymer Reverse Micelles for Transdermal Drug Delivery: Directing Carrier Properties by Tailoring Core versus Peripheral Branching.

The reverse micelle self-assembly of lipophile-functionalized poly(ethylene glycol) (PEG) dendrimer hybrids is probed for applications in carrier-mediated transdermal drug delivery. Under investigation are topologically diverse amphiphiles featuring controlled branching motifs at either the polymer core (one-, two-, and four-arm PEG) and the polar/nonpolar interface (peripheral dendritic generations 0-2). Thus, a systematic investigation of the effect of branching location (core vs peripheral) on carrier properties is described. Dye-encapsulation experiments verify these materials are capable of forming well-defined aggregates and solubilizing polar compounds. Further quantification of reverse micelle critical micelle concentration and dye loading capacity for the branched amphiphile library was obtained through spectroscopy characterization. Both core and peripheral branching are shown to significantly influence dynamic encapsulation behavior, with evidence of location-based contributions extending beyond multiplicity of branching alone. Finally, the in vitro transdermal diffusion of the reverse micelle carriers was investigated through Franz diffusion cell experiments using physiologically relevant juvenile porcine dermis. The permeation results, combined with previously reported aggregate size trends, show the complex relationship between polymer branching and transdermal transport, with the lowest core- and highest peripherally-branched amphiphilic analogs exhibiting optimal transdermal permeation characteristics for this set of branched carriers.

Determination of permeation pathways of hydrophilic or hydrophobic dyes through the mammary papilla.

The transport pathways and permeation kinetics of lipophilic and hydrophilic fluorescent dyes through porcine mammary papillae were visualized and quantified. Porcine mammary papillae, removed from full-thickness abdominal tissue, were positioned in a Franz diffusion cell for passive diffusion studies. Solutions containing the fluorescent dyes were applied topically for time periods ranging from 30 min to 48 h. Dye concentrations in tissue and Franz diffusion compartments were analyzed using fluorescence microscopy and fluorimetry. Fluorescence micrographs elucidated two permeation pathways, transepidermal and transductal. Hydrophilic sulforhodamine B predominantly penetrated via the transepidermal route, while lipophilic nile red diffused mainly by the transductal route. An almost 4-fold higher amount of sulforhodamine B was retained within the nipple over time compared to nile red, despite both dyes permeating through the tissue at similar rates. Diffusion through the porcine nipple was 500-fold higher than through adjacent skin for both dyes, likely attributable to the two mammary ducts which provide an entry point and transport route through the tissue. These results, generated from both qualitative and quantitative evidence at a micro and macro scale, demonstrate that the mammary ducts provide a direct pathway that contributes significantly to passive transport through the nipple, particularly for lipophilic molecules.

Neighbourhood demolition, relocation and health. A qualitative longitudinal study of housing-led urban regeneration in Glasgow, UK.

We conducted a qualitative longitudinal study to explore how adult residents of disadvantaged urban neighbourhoods (Glasgow, UK) experienced neighbourhood demolition and relocation. Data from 23 households was collected in 2011 and 2012. Some participants described moves to new or improved homes in different neighbourhoods as beneficial to their and their families' wellbeing. Others suggested that longstanding illnesses and problems with the new home and/or neighbourhood led to more negative experiences. Individual-level contextual differences, home and neighbourhood-level factors and variations in intervention implementation influence the experiences of residents involved in relocation programmes.

The novel adjuvant dmLT promotes dose sparing, mucosal immunity and longevity of antibody responses to the inactivated polio vaccine in a murine model.

One option for achieving global polio eradication is to replace the oral poliovirus vaccine (OPV), which has the risk of reversion to wild-type virulence, with the inactivated poliovirus vaccine (IPV) vaccine. Adjuvants and alternate routes of immunization are promising options that may reduce antigen dose in IPV vaccinations, potentially allowing dose sparing and cost savings. Use of adjuvants and alternate routes of immunization could also help promote mucosal immunity, potentially mimicking the protection against intestinal virus shedding seen with OPV. In the current study, we examined the impact of combining the novel adjuvant dmLT with trivalent IPV for dose sparing, induction of mucosal immunity and increasing longevity of anti-poliovirus (PV) responses in a mouse model following either intradermal (ID) or intramuscular (IM) delivery. We found that non-adjuvanted ID delivery was not superior to IM delivery for fractional dose sparing, but was associated with development of mucosal immunity. Vaccination with IPV+dmLT promoted serum anti-PV neutralizing antibodies with fractional IPV doses by either IM or ID delivery, achieving at least five-fold dose sparing above non-adjuvanted fractional doses. These responses were most noticeable with the PV1 component of the trivalent vaccine. dmLT also promoted germinal center formation and longevity of serum anti-PV neutralizing titers. Lastly, dmLT enhanced mucosal immunity, as defined by fecal and intestinal anti-PV IgA secretion, when included in IPV immunization by ID or IM delivery. These studies demonstrate that dmLT is an effective adjuvant for either IM or ID delivery of IPV. Inclusion of dmLT in IPV immunizations allows antigen dose sparing and enhances mucosal immunity and longevity of anti-PV responses.

The role of the mentor in evaluating learning.

This paper aims to give an overview of the role of the mentor within the sphere of the evaluation of learning, with particular emphasis on the intermediate interview and student reflection on their learning experience as formal tools for evaluation. Although the terms 'evaluation' and 'assessment' are often used in similar contexts, it is important to distinguish between the two concepts. The importance of evaluation of learning cannot be over emphasised as it is an important part of ensuring that students develop as expected (Nursing and Midwifery Council (NMC) 2008). Therefore, failure to evaluate learning can have a negative impact on the student and their learning throughout their programme of study.

The A subunit of Escherichia coli heat-labile enterotoxin functions as a mucosal adjuvant and promotes IgG2a, IgA, and Th17 responses to vaccine antigens.

Enterotoxigenic Escherichia coli (ETEC) produces both heat-labile (LT) and heat-stable (ST) enterotoxins and is a major cause of diarrhea in infants in developing countries and in travelers to those regions. In addition to inducing fluid secretion, LT is a powerful mucosal adjuvant capable of promoting immune responses to coadministered antigens. In this study, we examined purified A subunit to further understand the toxicity and adjuvanticity of LT. Purified A subunit was enzymatically active but sensitive to proteolytic degradation and unable to bind gangliosides, and even in the presence of admixed B subunit, it displayed low cyclic AMP (cAMP) induction and no enterotoxicity. Thus, the AB5 structure plays a key role in protecting the A subunit from proteolytic degradation and in delivering the enzymatic signals required for secretion. In contrast, the A subunit alone was capable of activating dendritic cells and enhanced immune responses to multiple antigens following intranasal immunization; therefore, unlike toxicity, LT adjuvanticity is not dependent on the AB5 holotoxin structure or the presence of the B subunit. However, immune responses were maximal when signals were received from both subunits either in an AB5 structure or with A and B admixed. Furthermore, the quality of the immune response (i.e., IgG1/IgG2 balance and mucosal IgA and IL-17 secretion) was determined by the presence of an A subunit, revealing for the first time induction of Th17 responses with the A subunit alone. These results have important implications for understanding ETEC pathogenesis, unraveling immunologic responses induced by LT-based adjuvants, and developing new mucosal vaccines.

In vitro degradation and release characteristics of spin coated thin films of PLGA with a "breath figure" morphology.

Poly (lactic-co-glycolic acid) (PLGA) coatings on implant materials are widely used in controlled drug delivery applications. Typically, such coatings are made with non-porous films. Here, we have synthesized a thin PLGA film coating with a highly ordered microporous structure using a simple and inexpensive water templating "breath figure" technique. A single stage process combining spin coating and breath figure process was used to obtain drug incorporated porous thin films. The films were characterized by scanning electron microscope (SEM) to observe the surface and bulk features of porosity and also, degradation pattern of the films. Moreover, the effect of addition of small amount of poly (ethylene glycol) (PEG) into PLGA was characterized. SEM analysis revealed an ordered array of ~2 µm sized pores on the surface with the average film thickness measured to be 20 µm. The incorporation of hydrophilic poly (ethylene glycol) (PEG) enhances pore structure uniformity and facilitates ingress of water into the structure. A five week in vitro degradation study showed a gradual deterioration of the breath figure pores. During the course of degradation, the surface pore structure deteriorates to initially flatten the surface. This is followed by the formation of new pinprick pores that eventually grow into a macroporous film prior to film breakup. Salicylic acid (highly water soluble) and Ibuprofen (sparingly water soluble) were chosen as model drug compounds to characterize release rates, which are higher in films of the breath figure morphology rather than in non-porous films. The results are of significance in the design of biodegradable films used as coatings to modulate delivery.

CPD for mentors: creating a portfolio.

It is a mandatory requirement for mentors to support and assess all pre-registration students in their practice areas. The role is time consuming and challenging, but can also be extremely rewarding. This article examines the roles and responsibilities of mentors and discusses the importance of continuing professional development for mentors. It also looks at how mentors can demonstrate they meet the standards required by the Nursing and Midwifery Council (2008b).

Improved dermal delivery of FITC-BSA using a combination of passive and active methods.

This work presents results on the in vitro penetration of a model macromolecule [fluorescein isothiocyanate-labeled bovine serum albumin (FITC-BSA)] through porcine skin, mediated with a microneedle skinroller (200-µm-length needle) and different novel formulations. After perforating the porcine skin with a microneedle skinroller, the efficiency of delivering FITC-BSA via different novel formulations was evaluated and compared. Formulations, including l-α-phosphatidylcholine (PC) liposomes, double emulsions, and double-encapsulation formulations were used. High-resolution cryo-scanning electron microscopy was used to visualize surface morphology and cross-section of perforated porcine skin. By the use of confocal microscopy, the penetration pathway and penetration depth of FITC-BSA through the perforated porcine skin under different formulations were analyzed. FITC-BSA was extracted from stratum corneum and viable skin, and analyzed by fluorimetry, indicating that there is no significant difference in the amount of FITC-BSA delivered to viable skin by PC-liposome suspension (12.90 ± 1.25 µg/cm(2)) versus double-encapsulation formulations (10.47 ± 0.80 µg/cm(2)); however, both formulations showed a significant increase as compared with an aqueous solution of FITC-BSA. In this work, double-encapsulation formulations were used in dermal delivery for the first time and combined with microneedle skinroller treatment, the results showed a high efficiency in delivering macromolecules.

Defending the mucosa: adjuvant and carrier formulations for mucosal immunity.

A majority of infectious microorganisms either colonize or cross mucosal surfaces to enter the host. A major goal in vaccine design is to induce a protective, lasting immune response against potential pathogens at mucosal surfaces. In addition, mucosal vaccines can offer needle-free delivery, thereby improving accessibility, safety, and cost-effectiveness. Challenges to successful mucosal vaccination include poor induction of mucosal immunity, limited understanding of protective mechanisms and crosstalk between mucosal compartments, and the availability of safe, effective mucosal adjuvants and delivery systems. This review focuses on some key advances in the field of mucosal vaccinology within the past 2-3 years, including reports on promising new formulations and investigations into the mechanisms of established mucosal adjuvants and/or particulate carrier systems.

Synthesis of amphiphilic star block copolymers and their evaluation as transdermal carriers.

Amphiphilic star polymers offer substantial promise for a range of drug delivery applications owing to their ability to encapsulate guest molecules. One appealing but underexplored application is transdermal drug delivery using star block copolymer reverse micelles as an alternative to the more common oral and intravenous routes. We prepared 6- and 12-arm amphiphilic star copolymers via atom transfer radical polymerization (ATRP) of sequential blocks of polar oligo (ethylene glycol)methacrylate and nonpolar lauryl methacrylate from brominated dendritic macroinitiators based on 2,2-bis(hydroxymethyl) propionic acid. These star block copolymers demonstrate the ability to encapsulate polar dyes such as rhodamine B and FITC-BSA in nonpolar media via UV/vis spectroscopic studies and exhibit substantially improved encapsulation efficiencies, relative to self-assembled "1-arm" linear block copolymer analogs. Furthermore, their transdermal carrier capabilities were demonstrated in multiple dye diffusion studies using porcine skin, verifying penetration of the carriers into the stratum corneum.

Characterization of a mutant Escherichia coli heat-labile toxin, LT(R192G/L211A), as a safe and effective oral adjuvant.

Despite the fact that the adjuvant properties of the heat-labile enterotoxins of Escherichia coli (LT) and Vibrio cholerae (CT) have been known for more than 20 years, there are no available oral vaccines containing these molecules as adjuvants, primarily because they are both very potent enterotoxins. A number of attempts with various degrees of success have been made to reduce or eliminate the enterotoxicity of LT and CT so they can safely be used as oral adjuvants or immunogens. In this report we characterize the structural, enzymatic, enterotoxic, and adjuvant properties of a novel mutant of LT, designated LT(R192G/L211A), or dmLT. dmLT was not sensitive to trypsin activation, had reduced enzymatic activity for induction of cyclic AMP in Caco-2 cells, and exhibited no enterotoxicity in the patent mouse assay. Importantly, dmLT retained the ability to function as an oral adjuvant for a coadministered antigen (tetanus toxoid) and to elicit anti-LT antibodies. In vitro and in vivo data suggest that the reduced enterotoxicity of this molecule compared to native LT or the single mutant, LT(R192G), is a consequence of increased sensitivity to proteolysis and rapid intracellular degradation in mammalian cells. In conclusion, dmLT is a safe and powerful detoxified enterotoxin with the potential to function as a mucosal adjuvant for coadministered antigens and to elicit anti-LT antibodies without undesirable side effects.

Oil-frozen W1/O/W2 double emulsions for dermal biomacromolecular delivery containing ethanol as chemical penetration enhancer.

Oil-frozen water-in-oil-in-water (W1/O/W2) double emulsions (DE) containing ethanol up to 40% (w/v) in the external aqueous W2 phase exhibited external coalescence upon thawing of the oil phase, releasing up to 85% of the encapsulated protein of the internal aqueous phase. These emulsions were studied in vitro as potential dermal macromolecular delivery formulations, achieving fluorescein isothiocyanate-labeled bovine serum albumin (FITC-BSA) penetration of up to 86 µm into porcine skin, reaching the viable epidermis where the immunocompetent Langerhans cells are located. Enzyme-linked immunosorbent assay was performed to observe the effect of the emulsification process and ethanol content on the ability of BSA to form antigen-antibody complexes; results indicated that ethanol content and the emulsification process did not diminish the BSA-antibody complex formation when compared with a BSA standard aqueous solution. Therefore, it is shown that oil-frozen W1/O/W2 DE, with penetration-enhancing ethanol in the W2 phase, can potentially be used for cutaneous vaccine delivery formulations.

Protocol for a mixed methods study investigating the impact of investment in housing, regeneration and neighbourhood renewal on the health and wellbeing of residents: the GoWell programme.

BACKGROUND: There is little robust evidence to test the policy assumption that housing-led area regeneration strategies will contribute to health improvement and reduce social inequalities in health. The GoWell Programme has been designed to measure effects on health and wellbeing of multi-faceted regeneration interventions on residents of disadvantaged neighbourhoods in the city of Glasgow, Scotland. METHODS/DESIGN: This mixed methods study focused (initially) on 14 disadvantaged neighbourhoods experiencing regeneration. These were grouped by intervention into 5 categories for comparison. GoWell includes a pre-intervention householder survey (n = 6008) and three follow-up repeat-cross sectional surveys held at two or three year intervals (the main focus of this protocol) conducted alongside a nested longitudinal study of residents from 6 of those areas. Self-reported responses from face-to-face questionnaires are analysed along with various routinely produced ecological data and documentary sources to build a picture of the changes taking place, their cost and impacts on residents and communities. Qualitative methods include interviews and focus groups of residents, housing managers and other stakeholders exploring issues such as the neighbourhood context, potential pathways from regeneration to health, community engagement and empowerment. DISCUSSION: Urban regeneration programmes are 'natural experiments.' They are complex interventions that may impact upon social determinants of population health and wellbeing. Measuring the effects of such interventions is notoriously challenging. GoWell compares the health and wellbeing effects of different approaches to regeneration, generates theory on pathways from regeneration to health and explores the attitudes and responses of residents and other stakeholders to neighbourhood change.