Search tips
Search criteria

Results 1-9 (9)

Clipboard (0)

Select a Filter Below

Year of Publication
Document Types
1.  Optimal Evidence in Difficult Settings: Improving Health Interventions and Decision Making in Disasters 
PLoS Medicine  2014;11(4):e1001632.
Martin Gerdin and colleagues argue that disaster health interventions and decision-making can benefit from an evidence-based approach
Please see later in the article for the Editors' Summary
PMCID: PMC3995669  PMID: 24755530
2.  A new zebrafish model produced by TILLING of SOD1-related amyotrophic lateral sclerosis replicates key features of the disease and represents a tool for in vivo therapeutic screening 
Disease Models & Mechanisms  2013;7(1):73-81.
Mutations in the superoxide dismutase gene (SOD1) are one cause of familial amyotrophic lateral sclerosis [ALS; also known as motor neuron disease (MND)] in humans. ALS is a relentlessly progressive neurodegenerative disease and, to date, there are no neuroprotective therapies with significant impact on the disease course. Current transgenic murine models of the disease, which overexpress mutant SOD1, have so far been ineffective in the identification of new therapies beneficial in the human disease. Because the human and the zebrafish (Danio rerio) SOD1 protein share 76% identity, TILLING (‘targeting induced local lesions in genomes’) was carried out in collaboration with the Sanger Institute in order to identify mutations in the zebrafish sod1 gene. A T70I mutant zebrafish line was characterised using oxidative stress assays, neuromuscular junction (NMJ) analysis and motor function studies. The T70I sod1 zebrafish model offers the advantage over current murine models of expressing the mutant Sod1 protein at a physiological level, as occurs in humans with ALS. The T70I sod1 zebrafish demonstrates key features of ALS: an early NMJ phenotype, susceptibility to oxidative stress and an adult-onset motor neuron disease phenotype. We have demonstrated that the susceptibility of T70I sod1 embryos to oxidative stress can be used in a drug screening assay, to identify compounds that merit further investigation as potential therapies for ALS.
PMCID: PMC3882050  PMID: 24092880
MND; ALS; SOD1; Zebrafish
3.  Augmented Dried versus Cryopreserved Amniotic Membrane as an Ocular Surface Dressing 
PLoS ONE  2013;8(10):e78441.
Dried amniotic membrane (AM) can be a useful therapeutic adjunct in ophthalmic surgery and possesses logistical advantages over cryopreserved AM. Differences in preservation techniques can significantly influence the biochemical composition and physical properties of AM, potentially affecting clinical efficacy. This study was established to investigate the biochemical and structural effects of drying AM in the absence and presence of saccharide lyoprotectants and its biocompatibility compared to cryopreserved material.
AM was cryopreserved or dried with and without pre-treatment with trehalose or raffinose and the antioxidant epigallocatechin (EGCG). Structural and visual comparisons were assessed using electron microscopy. Localisation, expression and release of AM biological factors were determined using immunoassays and immunofluorescence. The biocompatibility of the AM preparations co-cultured with corneal epithelial cell (CEC) or keratocyte monolayers were assessed using cell proliferation, cytotoxicity, apoptosis and migration assays.
Drying devitalised AM epithelium, but less than cryopreservation and cellular damage was reduced in dried AM pre-treated with trehalose or raffinose. Dried AM alone, and with trehalose or raffinose showed greater factor retention efficiencies and bioavailability compared to cryopreserved AM and demonstrated a more sustained biochemical factor time release in vitro. Cellular health assays showed that dried AM with trehalose or raffinose are compatible and superior substrates compared to cryopreserved AM for primary CEC expansion, with increased proliferation and reduced LDH and caspase-3 levels. This concept was supported by improved wound healing in an immortalised human CEC line (hiCEC) co-cultured with dried and trehalose or raffinose membranes, compared to cryopreserved and fresh AM.
Our modified preservation process and our resultant optimised dried AM has enhanced structural properties and biochemical stability and is a superior substrate to conventional cryopreserved AM. In addition this product is stable and easily transportable allowing it to be globally wide reaching for use in clinical and military sectors.
PMCID: PMC3813584  PMID: 24205233
4.  Opportunities for Improving Cancer Prevention at Federally Qualified Health Centers 
Journal of Cancer Education  2013;29(1):30-37.
As the Affordable Care Act unfolds, federally qualified health centers (FQHCs) will likely experience an influx of newly insured, low-income patients at disparate risk for cancer. Cancer-focused organizations are seeking to collaborate with FQHCs and the Primary Care Associations (PCAs) that serve them, to prevent cancer and reduce disparities. To guide this collaboration, we conducted 21 interviews with representatives from PCAs and FQHCs across four western states. We asked about: FQHC priorities, barriers and facilitators to cancer prevention, the PCA–FQHC relationship, and collaboration opportunities for external organizations. FQHC priorities include medical home transformation, electronic health records, and clinical care; prevention efforts must integrate with these. Barriers to cancer prevention include competing priorities, inadequate patient insurance, and lack of reimbursement, while facilitators are the presence of patient navigators and cancer-related performance measures. Collaboration opportunities for external organizations include dissemination of culturally appropriate educational materials and support for patient navigators.
PMCID: PMC3920058  PMID: 23996232
Cancer Prevention; Federally Qualified Health Center; Community Health Center; Primary Care Association
5.  The role of evidence, context, and facilitation in an implementation trial: implications for the development of the PARIHS framework 
The case has been made for more and better theory-informed process evaluations within trials in an effort to facilitate insightful understandings of how interventions work. In this paper, we provide an explanation of implementation processes from one of the first national implementation research randomized controlled trials with embedded process evaluation conducted within acute care, and a proposed extension to the Promoting Action on Research Implementation in Health Services (PARIHS) framework.
The PARIHS framework was prospectively applied to guide decisions about intervention design, data collection, and analysis processes in a trial focussed on reducing peri-operative fasting times. In order to capture a holistic picture of implementation processes, the same data were collected across 19 participating hospitals irrespective of allocation to intervention. This paper reports on findings from data collected from a purposive sample of 151 staff and patients pre- and post-intervention. Data were analysed using content analysis within, and then across data sets.
A robust and uncontested evidence base was a necessary, but not sufficient condition for practice change, in that individual staff and patient responses such as caution influenced decision making. The implementation context was challenging, in which individuals and teams were bounded by professional issues, communication challenges, power and a lack of clarity for the authority and responsibility for practice change. Progress was made in sites where processes were aligned with existing initiatives. Additionally, facilitators reported engaging in many intervention implementation activities, some of which result in practice changes, but not significant improvements to outcomes.
This study provided an opportunity for reflection on the comprehensiveness of the PARIHS framework. Consistent with the underlying tenant of PARIHS, a multi-faceted and dynamic story of implementation was evident. However, the prominent role that individuals played as part of the interaction between evidence and context is not currently explicit within the framework. We propose that successful implementation of evidence into practice is a planned facilitated process involving an interplay between individuals, evidence, and context to promote evidence-informed practice. This proposal will enhance the potential of the PARIHS framework for explanation, and ensure theoretical development both informs and responds to the evidence base for implementation.
Trial registration
ISRCTN18046709 - Peri-operative Implementation Study Evaluation (PoISE).
PMCID: PMC3636004  PMID: 23497438
6.  A pragmatic cluster randomised trial evaluating three implementation interventions 
Implementation research is concerned with bridging the gap between evidence and practice through the study of methods to promote the uptake of research into routine practice. Good quality evidence has been summarised into guideline recommendations to show that peri-operative fasting times could be considerably shorter than patients currently experience. The objective of this trial was to evaluate the effectiveness of three strategies for the implementation of recommendations about peri-operative fasting.
A pragmatic cluster randomised trial underpinned by the PARIHS framework was conducted during 2006 to 2009 with a national sample of UK hospitals using time series with mixed methods process evaluation and cost analysis. Hospitals were randomised to one of three interventions: standard dissemination (SD) of a guideline package, SD plus a web-based resource championed by an opinion leader, and SD plus plan-do-study-act (PDSA). The primary outcome was duration of fluid fast prior to induction of anaesthesia. Secondary outcomes included duration of food fast, patients’ experiences, and stakeholders’ experiences of implementation, including influences. ANOVA was used to test differences over time and interventions.
Nineteen acute NHS hospitals participated. Across timepoints, 3,505 duration of fasting observations were recorded. No significant effect of the interventions was observed for either fluid or food fasting times. The effect size was 0.33 for the web-based intervention compared to SD alone for the change in fluid fasting and was 0.12 for PDSA compared to SD alone. The process evaluation showed different types of impact, including changes to practices, policies, and attitudes. A rich picture of the implementation challenges emerged, including inter-professional tensions and a lack of clarity for decision-making authority and responsibility.
This was a large, complex study and one of the first national randomised controlled trials conducted within acute care in implementation research. The evidence base for fasting practice was accepted by those participating in this study and the messages from it simple; however, implementation and practical challenges influenced the interventions’ impact. A set of conditions for implementation emerges from the findings of this study, which are presented as theoretically transferable propositions that have international relevance.
Trial registration
ISRCTN18046709 - Peri-operative Implementation Study Evaluation (POISE).
PMCID: PMC3457838  PMID: 22935241
7.  Dogs are more permissive than cats or guinea pigs to experimental infection with a human isolate of Bartonella rochalimae  
Veterinary Research  2009;40(4):27.
Bartonella rochalimae was first isolated from the blood of a human who traveled to Peru and was exposed to multiple insect bites. Foxes and dogs are likely natural reservoirs for this bacterium. We report the results of experimental inoculation of two dogs, five cats and six guinea pigs with the only human isolate of this new Bartonella species. Both dogs became bacteremic for 5–7 weeks, with a peak of 103–104 colony forming units (CFU)/mL blood. Three cats had low bacteremia levels (< 200 CFU/mL) of 6–8 weeks’ duration. One cat that remained seronegative had two bacterial colonies isolated at a single culture time point. A fifth cat never became bacteremic, but seroconverted. None of the guinea pigs became bacteremic, but five seroconverted. These results suggest that dogs could be a reservoir of this strain of B. rochalimae, in contrast to cats and guinea pigs.
PMCID: PMC2695131  PMID: 19272295
Bartonella rochalimae; dogs; cats; guinea pigs; zoonosis
8.  Serum epidermal growth factor receptor and HER2 expression in primary and metastatic breast cancer patients 
Breast tissue expression of the ERBB proto-oncogene family has been extensively studied. It was recently shown that expression of epidermal growth factor receptor (EGFR; c-erbB-1) and epidermal growth factor receptor (HER)2 (c-erbB-2) can be detected in the serum of breast cancer patients. The clinical relevance of this has not been fully established.
EGFR and HER2 immunoassays were conducted in blood from 57 patients in whom paired serum samples were available (from the times of primary and metastatic diagnoses), from 96 primary breast cancer patients and from 49 normal individuals. Of the 57 patients with paired serum samples, paired tissue samples for HER2 expression were available for eight.
Serum levels of EGFR serum levels were significantly higher in normal individuals (median 75.3 ng/ml, range 43.2 to 114.2 ng/ml) than in patients with primary breast cancer (median 59.3 ng/ml, range 21.3 to 94.1 ng/ml; P < 0.001). In the paired serum samples, EGFR levels decreased significantly between the time of primary diagnosis (median 56.3 ng/ml, range 29.1 to 142.7 ng/ml) and metastatic diagnosis (median 30.9 ng/ml, range 10.9 to 106.4 ng/ml; P < 0.001). In six (11%) a change occurred from over-expression (>78 ng/ml) to normal expression. In contrast, no significant difference was seen in HER2 serum levels in normal individuals (median 12.2 ng/ml, range 7.8 to 20.9 ng/ml) and primary breast cancer patients (median 12.5 ng/ml, range 6.9 to 122.2 ng/ml; P = 0.511). However, in the paired serum samples, HER2 levels increased significantly between the time of primary (median 12.2 ng/ml, range 5.7 to 85.0 ng/ml) and metastasis (median 17.7 ng/ml, range 6.3 to 3,337.4 ng/ml; P < 0.001). HER2 over-expression (>15 ng/ml) was observed in 16 out of 57 patients (28%) at primary breast cancer diagnosis and in 31 out of 57 (54%) at metastasis. In 18 patients (32%) HER2 expression changed from normal to over-expression.
Decisions regarding the use of targeted therapies in the metastatic setting are often based on the oncogene expression of the primary tumour. Our results suggest that serum oncogene assessments may be complementary to this and could potentially widen the indications for these beneficial therapies.
PMCID: PMC2246171  PMID: 17976236
9.  TigarB causes mitochondrial dysfunction and neuronal loss in PINK1 deficiency 
Annals of Neurology  2014;74(6):837-847.
Loss of function mutations in PINK1 typically lead to early onset Parkinson disease (PD). Zebrafish (Danio rerio) are emerging as a powerful new vertebrate model to study neurodegenerative diseases. We used a pink1 mutant (pink−/−) zebrafish line with a premature stop mutation (Y431*) in the PINK1 kinase domain to identify molecular mechanisms leading to mitochondrial dysfunction and loss of dopaminergic neurons in PINK1 deficiency.
The effect of PINK1 deficiency on the number of dopaminergic neurons, mitochondrial function, and morphology was assessed in both zebrafish embryos and adults. Genome‐wide gene expression studies were undertaken to identify novel pathogenic mechanisms. Functional experiments were carried out to further investigate the effect of PINK1 deficiency on early neurodevelopmental mechanisms and microglial activation.
PINK1 deficiency results in loss of dopaminergic neurons as well as early impairment of mitochondrial function and morphology in Danio rerio. Expression of TigarB, the zebrafish orthologue of the human, TP53‐induced glycolysis and apoptosis regulator TIGAR, was markedly increased in pink−/− larvae. Antisense‐mediated inactivation of TigarB gave rise to complete normalization of mitochondrial function, with resulting rescue of dopaminergic neurons in pink−/− larvae. There was also marked microglial activation in pink−/− larvae, but depletion of microglia failed to rescue the dopaminergic neuron loss, arguing against microglial activation being a key factor in the pathogenesis.
Pink1−/− zebrafish are the first vertebrate model of PINK1 deficiency with loss of dopaminergic neurons. Our study also identifies TIGAR as a promising novel target for disease‐modifying therapy in PINK1‐related PD. Ann Neurol 2013;74:837–847
PMCID: PMC4154126  PMID: 24027110

Results 1-9 (9)