Liposome-mediated DNA immunisation via the subcutaneous route

Compared to naked DNA immunisation, entrapment of plasmid-based DNA vaccines into liposomes by the dehydration-rehydration method has shown to enhance both humoural and cell-mediated immune responses to encoded antigens administered by a variety of routes. In this paper, we have investigated the application of liposome-entrapped DNA and their cationic lipid composition on such potency after subcutaneous immunisation. Plasmid pI.18Sfi/NP containing the nucleoprotein (NP) gene of A/Sichuan/2/87 (H3N2) influenza virus in the pI.18 expression vector was incorporated by the dehydration-rehydration method into liposomes composed of 16 μmol egg phosphatidylcholine (PC), 8 μmoles dioleoyl phosphatidylethanolamine (DOPE) or cholesterol (Chol) and either the cationic lipid 1,2-diodeoyl-3-(trimethylammonium) propane (DOTAP) or cholesteryl 3-N-(dimethyl amino ethyl) carbamate (DC-Chol). This method, entailing mixing of small unilamellar vesicles (SUV) with DNA, followed by dehydration and rehydration, yielded incorporation values of 90-94% of the DNA used. Mixing or rehydration of preformed cationic liposomes with 100 μg plasmid DNA also led to similarly high complexation values (92-94%). In an attempt to establish differences in the nature of DNA association with these various liposome preparations their physico-chemical characteristics were investigated. Studies on vesicle size, zeta potential and gel electrophoresis in the presence of the anion sodium dodecyl sulphate (SDS) indicate that, under the conditions employed, formulation of liposomal DNA by the dehydration-rehydration generated submicron size liposomes incorporating most of the DNA in a manner that prevents DNA displacement through anion competition. The bilayer composition of these dehydration-rehydration vesicles (DRV(DNA)) can also further influence these physicochemical characteristics with the presence of DOPE within the liposome bilayer resulting in a reduced vesicle zeta potential. Subcutaneous liposome-mediated DNA immunisation employing two DRV(DNA) formulations as well as naked DNA revealed that humoural responses (immunoglobulin total IgG, and subclasses IgG1 and 1gG2a) engendered by the plasmid encoded NP were substantially higher after dosing twice, 28 days apart with 10 μg liposome-entrapped DNA compared to naked DNA. At all time points measured, mice immunised with naked DNA showed no greater immune response compared to the control, non-immunised group. In contrast, as early as day 49, responses were significantly higher in mice injected with DNA entrapped in DRV liposomes containing DOTAP compared to the control group and mice immunised with naked DNA. By day 56, all total IgG responses from mice immunised with both DRV formulations were significantly higher. Comparison between the DRV formulations revealed no significant difference in immune responses elicited except at day 114, where the humoural responses of the group injected with liposomal formulation containing DC-Chol dropped to significantly lower levels that those measured in mice which received the DOTAP formulation. Similar results were found when the IgG1 and IgG2a subclass responses were determined. These results suggest that, not only can DNA be effectively entrapped within liposomes using the DRV method but that such DRV liposomes containing DNA may be a useful system for subcutaneous delivery of DNA vaccines. © 2003 Taylor & Francis Ltd.

The two-dose measles, mumps, and rubella (MMR) immunisation schedule: factors affecting maternal intention to vaccinate

BACKGROUND: In the light of sub-optimal uptake of the measles, mumps, and rubella (MMR) vaccination, we investigated the factors that influence the intentions of mothers to vaccinate. METHOD: A cross-sectional survey of 300 mothers in Birmingham with children approaching a routine MMR vaccination was conducted using a postal questionnaire to measure: intention to vaccinate, psychological variables, knowledge of the vaccine, and socioeconomic status. The vaccination status of the children was obtained from South Birmingham Child Health Surveillance Unit. RESULTS: The response rate was 59%. Fewer mothers approaching the second MMR vaccination (Group 2) intended to take their children for this vaccination than Group 1 (mothers approaching the first MMR vaccination) (Mann-Whitney U = 2180, P < 0.0001). Group 2 expressed more negative beliefs about the outcome of having the MMR vaccine ('vaccine outcome beliefs') (Mann-Whitney U = 2155, P < 0.0001), were more likely to believe it was 'unsafe' (chi 2 = 9.114, P = 0.004) and that it rarely protected (chi 2 = 6.882, P = 0.014) than Group 1. The commonest side-effect cited was general malaise, but 29.8% cited autism. The most trusted source of information was the general practitioner but the most common source of information on side-effects was television (34.6%). Multiple linear regression revealed that, in Group 1, only 'vaccine outcome beliefs' significantly predicted intention (77.1% of the variance). In Group 2 'vaccine outcome beliefs', attitude to the MMR vaccine, and prior MMR status all predicted intention (93% of the variance). CONCLUSION: A major reason for the low uptake of the MMR vaccination is that it is not perceived to be important for children's health, particularly the second dose. Health education from GPs is likely to have a considerable impact.

A tree-based decision model to support prediction of the severity of asthma exacerbations in children

This paper describes the development of a tree-based decision model to predict the severity of pediatric asthma exacerbations in the emergency department (ED) at 2 h following triage. The model was constructed from retrospective patient data abstracted from the ED charts. The original data was preprocessed to eliminate questionable patient records and to normalize values of age-dependent clinical attributes. The model uses attributes routinely collected in the ED and provides predictions even for incomplete observations. Its performance was verified on independent validating data (split-sample validation) where it demonstrated AUC (area under ROC curve) of 0.83, sensitivity of 84%, specificity of 71% and the Brier score of 0.18. The model is intended to supplement an asthma clinical practice guideline, however, it can be also used as a stand-alone decision tool.

Intern pharmacists as change agents to improve the practice of nonprescription medication supply: provision of salbutamol to patients with asthma

BACKGROUND: Earlier work established an evidence practice gap during provision of nonprescription salbutamol (albuterol). Pharmacist interns are hypothesized to be in a position to improve professional practice in the community pharmacy setting. OBJECTIVE: To explore the potential of intern pharmacists to improve the professional practice of community pharmacy staff in the provision of nonprescription salbutamol. METHODS: Intern pharmacists (n = 157) delivered an asthma intervention in 136 pharmacies consisting of an educational activity to pharmacy staff and a health promotion campaign to consumers. Post-intervention, simulated patients presented to 100 intervention and 100 control community pharmacies with a request for salbutamol. The appropriate outcome was medical referral for poor asthma control and correction of poor inhaler technique. Incidence and quantity of patient assessment and counseling provided during the visit were also assessed. Logistic regression was used to determine the predictors of medical referral. RESULTS: A doubling in the rate of medical referral was seen in the intervention group (19% vs 40%; p = 0.001). Assessment of reliever use frequency was the main predictor of medical referral (OR = 22.7; 95% CI 9.06 to 56.9). Correction of poor inhaler technique did not improve; however, a reduction in salbutamol supplied without patient assessment (23% vs 8%; p = 0.009) or counseling (75% vs 48%; p < 0.001) was noted. CONCLUSIONS: A doubling in the rate of medical referral showed a clear improvement in professional practice during the provision of nonprescription salbutamol. The improved patient outcome in the intervention group was due to increased assessment of reliever use frequency. Identification of poor inhaler technique remained near zero in both groups, which suggests that intern pharmacists were able to improve the current practice of community pharmacies yet were unable to establish a new practice behavior. This study provides evidence that intern pharmacists can act as change agents to improve pharmacy practice.

Measuring the assessment and counselling provided with the supply of non-prescription asthma reliever medication: a simulated patient study

BACKGROUND: Over one quarter of asthma reliever medications are provided without prescription by community pharmacies in Australia. Evidence that community pharmacies provide these medications with sufficient patient assessment and medication counseling to ensure compliance with the government's Quality Use of Medicines principles is currently lacking. OBJECTIVE: To assess current practice when asthma reliever medication is provided in the community pharmacy setting and to identify factors that correlate with assessment of asthma control. METHODS: Researchers posing as patients visited a sample of Perth metropolitan community pharmacies in May 2007. During the visit, the simulated patient enacted a standardized scenario of someone with moderately controlled asthma who wished to purchase a salbutamol (albuterol) inhaler without prescription. Results of the encounter were recorded immediately after the visit. Regression analysis was performed, with medication use frequency (a marker of asthma control) as the dependent variable. RESULTS: One hundred sixty community pharmacies in the Perth metropolitan area were visited in May 2007. Pharmacists and/or pharmacy assistants provided some form of assessment in 84% of the visits. Counseling was provided to the simulated patients in 24% of the visits. Only 4 pharmacy staff members asked whether the simulated patient knew how to use the inhaler. Significant correlation was found between assessment and/or counseling of reliever use frequency and 3 independent variables: visit length (p < 0.001), number of assessment questions asked (p < 0.001), and the simulated patient who conducted the visit (p < 0.02). CONCLUSIONS: Both patient assessment and medication counseling were suboptimal compared with recommended practice when nonprescription asthma reliever medication was supplied in the community pharmacy setting. Pharmacy and pharmacist demographic variables do not appear to affect assessment of asthma control. This research indicates the need for substantial improvements in practice in order to provide reliever medication in line with Quality Use of Medication principles of ensuring safe and effective use of medication.

Asthma management : implementation of short-acting beta agonist guidelines in Western Australia:a unique collaboration

Background: The Respiratory Health Network in Western Australia developed the Asthma Model of Care in 2010 which incorporates best practice guidelines. At the same time short-acting beta agonist guidelines (SABA) were developed by stakeholder consensus at University of Western Australia (UWA) and incorporated the use of an Asthma Action Plan Card. Objective: To report on the implementation of a key component of the WA Asthma Model of Care, the SABA guidelines that incorporate the Asthma Action Plan card. Methods: Implementation strategies included lectures, direct pharmacy detailing, media releases, and information packs (postal and electronic). Groups targeted included pharmacists, consumers and medical practitioners. Results: State-based (n=18) and national (n=6) professional organisations were informed about the launch of the guidelines into practice in WA. In the four-month implementation period more than 47,000 Asthma Action Plan Cards were distributed, primarily to community pharmacies. More than 500 pharmacies were provided with information packs or individual detailing. More than 10,000 consumers were provided with information about the guidelines. Conclusions and implications: The collaboration of stakeholders in this project allowed for widespread access to various portals which, in turn, resulted in a multifaceted approach in disseminating information. Ongoing maintenance programs are required to sustain and build on the momentum of the implementation program and to ultimately address patient outcomes and practice change, which would be the longer-term goals of such a project. Future research will seek to ascertain the impact of the card on patient outcomes in WA.

A comparative study of cationic liposome and niosome-based adjuvant systems for protein subunit vaccines:characterisation, environmental scanning electron microscopy and immunisation studies in mice

Vesicular adjuvant systems composing dimethyldioctadecylammonium (DDA) can promote both cell-mediated and humoral immune responses to the tuberculosis vaccine fusion protein in mice. However, these DDA preparations were found to be physically unstable, forming aggregates under ambient storage conditions. Therefore there is a need to improve the stability of such systems without undermining their potent adjuvanticity. To this end, the effect of incorporating non-ionic surfactants, such as 1-monopalmitoyl glycerol (MP), in addition to cholesterol (Chol) and trehalose 6,6′-dibehenate (TDB), on the stability and efficacy of these vaccine delivery systems was investigated. Differential scanning calorimetry revealed a reduction in the phase transition temperature (T c) of DDA-based vesicles by ∼12°C when MP and cholesterol (1:1 molar ratio) were incorporated into the DDA system. Transmission electron microscopy (TEM) revealed the addition of MP to DDA vesicles resulted in the formation of multi-lamellar vesicles. Environmental scanning electron microscopy (ESEM) of MP-Chol-DDA-TDB (16:16:4:0.5 μmol) indicated that incorporation of antigen led to increased stability of the vesicles, perhaps as a result of the antigen embedding within the vesicle bilayers. At 4°C DDA liposomes showed significant vesicle aggregation after 28 days, although addition of MP-Chol or TDB was shown to inhibit this instability. Alternatively, at 25°C only the MP-based systems retained their original size. The presence of MP within the vesicle formulation was also shown to promote a sustained release of antigen in-vitro. The adjuvant activity of various systems was tested in mice against three subunit antigens, including mycobacterial fusion protein Ag85b-ESAT-6, and two malarial antigens (Merozoite surface protein 1, MSP1, and the glutamate rich protein, GLURP). The MP- and DDA-based systems induced antibody responses at comparable levels whereas the DDA-based systems induced more powerful cell-mediated immune responses. © 2006 The Authors.

Rapid testing for group B streptococcus during labour: a test accuracy study with evaluation of acceptability and cost-effectiveness

OBJECTIVE: To determine the accuracy, acceptability and cost-effectiveness of polymerase chain reaction (PCR) and optical immunoassay (OIA) rapid tests for maternal group B streptococcal (GBS) colonisation at labour. DESIGN: A test accuracy study was used to determine the accuracy of rapid tests for GBS colonisation of women in labour. Acceptability of testing to participants was evaluated through a questionnaire administered after delivery, and acceptability to staff through focus groups. A decision-analytic model was constructed to assess the cost-effectiveness of various screening strategies. SETTING: Two large obstetric units in the UK. PARTICIPANTS: Women booked for delivery at the participating units other than those electing for a Caesarean delivery. INTERVENTIONS: Vaginal and rectal swabs were obtained at the onset of labour and the results of vaginal and rectal PCR and OIA (index) tests were compared with the reference standard of enriched culture of combined vaginal and rectal swabs. MAIN OUTCOME MEASURES: The accuracy of the index tests, the relative accuracies of tests on vaginal and rectal swabs and whether test accuracy varied according to the presence or absence of maternal risk factors. RESULTS: PCR was significantly more accurate than OIA for the detection of maternal GBS colonisation. Combined vaginal or rectal swab index tests were more sensitive than either test considered individually [combined swab sensitivity for PCR 84% (95% CI 79-88%); vaginal swab 58% (52-64%); rectal swab 71% (66-76%)]. The highest sensitivity for PCR came at the cost of lower specificity [combined specificity 87% (95% CI 85-89%); vaginal swab 92% (90-94%); rectal swab 92% (90-93%)]. The sensitivity and specificity of rapid tests varied according to the presence or absence of maternal risk factors, but not consistently. PCR results were determinants of neonatal GBS colonisation, but maternal risk factors were not. Overall levels of acceptability for rapid testing amongst participants were high. Vaginal swabs were more acceptable than rectal swabs. South Asian women were least likely to have participated in the study and were less happy with the sampling procedure and with the prospect of rapid testing as part of routine care. Midwives were generally positive towards rapid testing but had concerns that it might lead to overtreatment and unnecessary interference in births. Modelling analysis revealed that the most cost-effective strategy was to provide routine intravenous antibiotic prophylaxis (IAP) to all women without screening. Removing this strategy, which is unlikely to be acceptable to most women and midwives, resulted in screening, based on a culture test at 35-37 weeks' gestation, with the provision of antibiotics to all women who screened positive being most cost-effective, assuming that all women in premature labour would receive IAP. The results were sensitive to very small increases in costs and changes in other assumptions. Screening using a rapid test was not cost-effective based on its current sensitivity, specificity and cost. CONCLUSIONS: Neither rapid test was sufficiently accurate to recommend it for routine use in clinical practice. IAP directed by screening with enriched culture at 35-37 weeks' gestation is likely to be the most acceptable cost-effective strategy, although it is premature to suggest the implementation of this strategy at present.

Intrapartum tests for group B streptococcus:accuracy and acceptability of screening

Objective: To assess the accuracy and acceptability of polymerase chain reaction (PCR) and optical immunoassay (OIA) tests for the detection of maternal group B streptococcus (GBS) colonisation during labour, comparing their performance with the current UK policy of risk factor-based screening. Design Diagnostic test accuracy study. Setting and population Fourteen hundred women in labour at two large UK maternity units provided vaginal and rectal swabs for testing. Methods The PCR and OIA index tests were compared with the reference standard of selective enriched culture, assessed blind to index tests. Factors influencing neonatal GBS colonisation were assessed using multiple logistic regression, adjusting for antibiotic use. The acceptability of testing to participants was evaluated through a structured questionnaire administered after delivery. Main outcome measures The sensitivity and specificity of PCR, OIA and risk factor-based screening. Results Maternal GBS colonisation was 21% (19-24%) by combined vaginal and rectal swab enriched culture. PCR test of either vaginal or rectal swabs was more sensitive (84% [79-88%] versus 72% [65-77%]) and specific (87% [85-89%] versus 57% [53-60%]) than OIA (P <0.001), and far more sensitive (84 versus 30% [25-35%]) and specific (87 versus 80% [77-82%]) than risk factor-based screening (P <0.001). Maternal antibiotics (odds ratio, 0.22 [0.07-0.62]; P = 0.004) and a positive PCR test (odds ratio, 29.4 [15.8-54.8]; P <0.001) were strongly related to neonatal GBS colonisation, whereas risk factors were not (odds ratio, 1.44 [0.80-2.62]; P = 0.2). Conclusion Intrapartum PCR screening is a more accurate predictor of maternal and neonatal GBS colonisation than is OIA or risk factor-based screening, and is acceptable to women. © RCOG 2010 BJOG An International Journal of Obstetrics and Gynaecology.

Patient education in the treatment of asthma:a controlled evaluation of providing information for "new" asthmatics

DUE TO COPYRIGHT RESTRICTIONS ONLY AVAILABLE FOR CONSULTATION AT ASTON UNIVERSITY LIBRARY AND INFORMATION SERVICES WITH PRIOR ARRANGEMENT

Can certain genotypes predispose to poor asthma control in children? A pharmacogenetic study of 9 candidate genes in children with difficult asthma

Objective - We tested the hypothesis that patients with difficult asthma have an increased frequency of certain genotypes that predispose them to asthma exacerbations and poor asthma control. Methods - A total of 180 Caucasian children with confirmed asthma diagnosis were selected from two phenotypic groups; difficult (n = 112) versus mild/moderate asthma (n = 68) groups. All patients were screened for 19 polymorphisms in 9 candidate genes to evaluate their association with difficult asthma. Key Results - The results indicated that LTA4H A-9188>G, TNFα G-308>A and IL-4Rα A1727>G polymorphisms were significantly associated with the development of difficult asthma in paediatric patients (p<0.001, p = 0.019 and p = 0.037, respectively). Haplotype analysis also revealed two haplotypes (ATA haplotype of IL-4Rα A1199>C, IL-4Rα T1570>C and IL-4Rα A1727>G and CA haplotype of TNFα C-863>A and TNFα G-308>A polymorphisms) which were significantly associated with difficult asthma in children (p = 0.04 and p = 0.018, respectively). Conclusions and Clinical Relevance - The study revealed multiple SNPs and haplotypes in LTA4H, TNFα and IL4-Rα genes which constitute risk factors for the development of difficult asthma in children. Of particular interest is the LTA4H A-9188>G polymorphism which has been reported, for the first time, to have strong association with severe asthma in children. Our results suggest that screening for patients with this genetic marker could help characterise the heterogeneity of responses to leukotriene-modifying medications and, hence, facilitate targeting these therapies to the subset of patients who are most likely to gain benefit.

Patient-reported outcome measures for asthma:a systematic review

BACKGROUND: Patient-reported outcome measures (PROMs) are measures of the outcome of treatment(s) reported directly by the patient or carer. There is increasing international policy interest in using these to assess the impact of clinical care. AIMS: To identify suitably validated PROMs for asthma and examine their potential for use in clinical settings. METHODS: We systematically searched MEDLINE, EMBASE and Web of Science databases from 1990 onwards to identify PROMs for asthma. These were critically appraised, then narratively synthesised. We also identified the generic PROMs commonly used alongside asthma-specific PROMs. RESULTS: We identifi ed 68 PROMs for asthma, 13 of which were selected through screening as being adequately developed to warrant full-quality appraisal: 8 for adults, 4 for children and 1 for a child's caregiver. The PROMs found to be sufficiently well validated to offer promise for use in clinical settings were the Asthma Quality of Life Questionnaire (AQLQ) and mini-AQLQ for adults, and Pediatric Asthma Quality of Life Questionnaire for children. Rhinasthma was considered promising in simultaneously assessing the impact of asthma and rhinitis in those with coexistent disease. We identified 28 generic PROMs commonly used in conjunction with asthma-specific instruments. CONCLUSIONS: We identified asthma PROMs that offer the greatest potential for use in clinical settings. Further work is needed to assess whether these are fit-for-purpose for use in clinical practice with individual patients. In particular, there is a need to ensure these are validated for use in clinical settings, acceptable to patients, caregivers and clinicians, and yield meaningful outcomes. © 2014 Primary Care Respiratory Society/Macmillan Publishers Limited.

Barriers and facilitators to asthma self-management in adolescents:a systematic review of qualitative and quantitative studies

BACKGROUND: Many adolescents have poor asthma control and impaired quality of life despite the availability of modern pharmacotherapy. Research suggests that poor adherence to treatment and limited engagement in self-management could be contributing factors. OBJECTIVE: To conduct a systematic review of the barriers and facilitators to self-management of asthma reported by adolescents using a narrative synthesis approach to integrate the findings. DESIGN: MEDLINE, EMBASE, CINAHL, and PsycINFO were searched for all types of study design. Full papers were retrieved for study abstracts that included data from participants aged 12-18 years referring to barriers or facilitators of asthma self-management behaviors. RESULTS: Sixteen studies (5 quantitative and 11 qualitative) underwent data extraction, quality appraisal, and thematic analysis. Six key themes were generated that encompassed barriers and/or facilitators to self-management of asthma in adolescents: Knowledge, Lifestyle, Beliefs and Attitudes, Relationships, Intrapersonal Characteristics, and Communication. CONCLUSIONS: There is a pressing need to prepare adolescents for self-management, using age-appropriate strategies that draw on the evidence we have synthesized. Current clinical practice should focus on ensuring adolescents have the correct knowledge, beliefs, and positive attitude to self-manage their illness. This needs to be delivered in a supportive environment that facilitates two-way communication, fosters adolescents' self-efficacy to manage their disease, and considers the wider social influences that impinge on self-management. Pediatr Pulmonol. 2016; 9999:XX-XX. © 2016 Wiley Periodicals, Inc.