Biomarkers for personalised prevention of chronic diseases: a common protocol for three rapid scoping reviews.

INTRODUCTION: Personalised prevention aims to delay or avoid disease occurrence, progression, and recurrence of disease through the adoption of targeted interventions that consider the individual biological, including genetic data, environmental and behavioural characteristics, as well as the socio-cultural context. This protocol summarises the main features of a rapid scoping review to show the research landscape on biomarkers or a combination of biomarkers that may help to better identify subgroups of individuals with different risks of developing specific diseases in which specific preventive strategies could have an impact on clinical outcomes. This review is part of the "Personalised Prevention Roadmap for the future HEalThcare" (PROPHET) project, which seeks to highlight the gaps in current personalised preventive approaches, in order to develop a Strategic Research and Innovation Agenda for the European Union. OBJECTIVE: To systematically map and review the evidence of biomarkers that are available or under development in cancer, cardiovascular and neurodegenerative diseases that are or can be used for personalised prevention in the general population, in clinical or public health settings. METHODS: Three rapid scoping reviews are being conducted in parallel (February-June 2023), based on a common framework with some adjustments to suit each specific condition (cancer, cardiovascular or neurodegenerative diseases). Medline and Embase will be searched to identify publications between 2020 and 2023. To shorten the time frames, 10% of the papers will undergo screening by two reviewers and only English-language papers will be considered. The following information will be extracted by two reviewers from all the publications selected for inclusion: source type, citation details, country, inclusion/exclusion criteria (population, concept, context, type of evidence source), study methods, and key findings relevant to the review question/s. The selection criteria and the extraction sheet will be pre-tested. Relevant biomarkers for risk prediction and stratification will be recorded. Results will be presented graphically using an evidence map. INCLUSION CRITERIA: Population: general adult populations or adults from specific pre-defined high-risk subgroups; concept: all studies focusing on molecular, cellular, physiological, or imaging biomarkers used for individualised primary or secondary prevention of the diseases of interest; context: clinical or public health settings. SYSTEMATIC REVIEW REGISTRATION: https://doi.org/10.17605/OSF.IO/7JRWD (OSF registration DOI).

Implementation of an integrated community approach in deprived neighbourhoods: a theory-based process evaluation using the Consolidated Framework for Implementation Research (CFIR).

BACKGROUND: We investigated the implementation process of an Integrated Community Approach (ICA) applied in four low socio-economic status neighbourhoods in Maastricht, the Netherlands. The ICA is a Population Health Management initiative and aims to improve population health, quality of care, professional's satisfaction and decrease costs of care. This study addresses the facilitators and barriers for implementing the ICA from a stakeholder perspective, including steering group members, professionals and citizens. METHODS: We conducted a mixed-methods study using a triangulation of methods to investigate the implementation from 1 December 2016 to 31 December 2020. The Consolidated Framework for Implementation Research guided data collection and data-analysis for evaluating the implementation process. In total, 77 interviews, 97 observations, seven focus groups, 65 collected documents and two surveys with open-ended questions were conducted. RESULTS: Facilitators for implementation were the use of citizen science to bring residents' needs into sharp focus, the integration of the ideology of Positive Health into the working routines of the professionals and leadership at the steering group level to overcome barriers in the ICA. The existing accounting and financial infrastructure obstructed combining budgets at neighbourhood level. CONCLUSIONS: Engaging citizens and professionals at an early stage is an important facilitator for implementation. The use of a shared vision on health also worked as a facilitator since it created a shared language among professionals, which is important in Population Health Management initiatives where multiple professionals are expected to collaborate. TRIAL REGISTRATION: NTR 6543; registration date, 25 July 2017.

Collaborative governance at the start of an integrated community approach: a case study.

BACKGROUND: We studied collaborative governance at the start of an integrated community approach aiming to improve population health, quality of care, controlling health care costs and improving professional work satisfaction. Our objective was to investigate which characteristics of collaborative governance facilitate or hamper collaboration in the starting phase. This question is of growing importance for policymakers and health initiatives, since on a global scale there is a shift towards 'population health management' where collaboration between stakeholders is a necessity. In addition, it is crucial to investigate collaborative governance from the beginning, since it offers opportunities for sustainability of collaboration later on in the process. METHODS: We performed a qualitative case study in four deprived neighbourhoods in the city of Maastricht, the Netherlands. An integrated community approach was implemented, involving various stakeholders from the public and private health sectors and provincial and local authorities. Data was collected from December 2016 to December 2018, with a triangulation of methods (50 observations, 24 interviews and 50 document reviews). The Integrative Framework for Collaborative Governance guided data collection and analysis. RESULTS: We focused on the dynamics within the collaborative governance regime, consisting of principled engagement, shared motivation and capacity for joint action. We found that shared goalsetting, transparency, being physically present, informal meetings, trust and leadership are key aspects at the start of collaborative governance. An extensive accountability structure can both hamper (time-consuming which hinders innovation) and facilitate (keep everybody on board) collaboration. The characteristics we found are of significance for policy, practice and research. Policymakers and practitioners can use our lessons learned for implementing similar (population health) initiatives. This case study contributes to the already existing literature on collaborative governance adding to the knowledge gap on the governance of population health approaches. TRIAL REGISTRATION: NTR6543 , registration date; 25 July 2017.

Citizen science in the community: Gaining insight in community and participant health in four deprived neighbourhoods in the Netherlands.

The aim of this study was to examine if citizen science contributes to gaining insight into community health and to the health of the citizen scientists themselves. Therefore, thirteen citizens in four deprived neighbourhoods were trained as citizen scientists to conduct research in their own communities. Results showed that the citizen scientists identified forty (health related) themes in their communities. The citizen scientists reported an increase in their overall self-perceived health which, however, was not significantly demonstrated in the prequestionnaire and postquestionnaire.

Nurse-led stroke aftercare addressing long-term psychosocial outcome: a comparison to care-as-usual.

PURPOSE: To examine whether nurse-led stroke aftercare is beneficial for long-term psychosocial outcome of community-dwelling persons with stroke. MATERIALS AND METHODS: Comparative effectiveness research design in which a prospective stroke aftercare cohort (n = 87) was compared to care-as-usual (n = 363) at six- and 12-months post stroke. Changes over time in cognitive and emotional problems experienced in daily life, fatigue and stroke impact on daily life were examined for stroke aftercare only. Multilevel modelling was used to compare stroke aftercare to care-as-usual concerning anxiety and depression symptoms, social participation and quality of life, over time. RESULTS: Sample characteristics did not differ between cohorts except for stroke type and on average, more severe stroke in the stroke aftercare cohort (p < 0.05). Following stroke aftercare, anxiety and emotional problems decreased significantly (p < 0.05), whereas care-as-usual remained stable over time in terms of anxiety. No significant changes over time were observed on the other outcome domains. CONCLUSIONS: Nurse-led stroke aftercare showed to be beneficial for emotional well-being in comparison to care-as-usual. Providing psychoeducation and emotional support seem effective elements but adding other therapeutic elements such as self-management strategies might increase the effectiveness of nurse-led stroke aftercare.Implications for rehabilitationRoutine stroke follow-up care should pay attention to psychosocial and emotional outcome in a systematic manner, in addition to secondary prevention.Healthcare professionals such as (specialized) nurses are needed to appropriately address the hidden cognitive and emotional consequences of stroke.Providing psychoeducation and emotional support in stroke aftercare diminish insecurities and worries in community-dwelling persons with stroke, leading to better outcomes.

A patient decision aid for breast cancer patients deciding on their radiation treatment, no change in decisional conflict but better informed choices.

BACKGROUND AND PURPOSE: In selected breast cancer patients, radiation treatment (RT) lowers the recurrence risk, with minor or no improvement of survival. In these patients, the choice to undergo RT is considered a preference-sensitive decision. To facilitate shared decision-making (SDM) for this choice, a patient decision aid was made. We aimed to evaluate the effect of the PtDA on decisional conflict. MATERIAL AND METHODS: We performed a multi-center pre- and post-intervention study (BRASA-trial). The first 214 patients made a choice without support of the PtDA; the subsequent 189 patients received a link to the PtDA. The primary endpoint was decisional conflict; secondary endpoints were perceived SDM and knowledge on treatment options. Patients filled out questionnaires immediately after, and three months after their decision. Data were analyzed with multi-level regression analysis. RESULTS: After correcting for the difference in age and educational level, the mean (±SD) decisional conflict for the intervention group (27.3 ± 11.4) was similar to the control group (26.8 ± 11.4; difference = 0.86, 95 %CI 1.67,3.36) three months after their decision. This also applied to perceived SDM. Patients exposed to the PtDA pursued additional treatment less often (45% vs 56%, odds ratio 0.59, 95 %CI 0.37,0.95) and scored significantly higher on the knowledge test (7.4 ± 2.5 vs 6.1 ± 2.7, corrected difference = 1.0, 95 %CI 0.50,1.49). There was no significant increase in consultation time. CONCLUSIONS: Handing out the PtDA was not associated with improved scores in decisional conflict or perceived SDM, but it was associated with a choice for less additional treatment and better knowledge about the treatment options.

Implementing a patient decision aid, a process evaluation of a large-scale pre- and post-implementation trial.

PURPOSE: Patient decision aids (PtDAs) have been reported to have a positive influence on patients making a health care decision in trials. Nevertheless, post-trial implementation is poor. The aim of this study is to explore patient, clinician, and organizational success factors for implementing a PtDA designed for breast cancer patients, facing a decision on their radiation treatment. METHODS: We performed a process evaluation within a multi-center pre- and post-implementation trial. The PtDA was incorporated as much as possible in the logistics of 13 participating centers. Tracking data were collected on PtDA use. Process characteristics were recorded by both clinicians and patients. A logistic regression method was applied to investigate which process characteristics were significantly related to the probability that patients logged in to the PtDA. RESULTS: 189 patients received the PtDA of whom140 (77%) used the PtDA. If patients received the link via the surgery department they were more likely to use the PtDA (OR 9.77 (1.28-74.51)), compared to patients that received the link via the radiation oncology department. If the report of the multidisciplinary team stated that radiation treatment "had to be discussed with the patient", patients were more likely to use the PtDA (OR 2.29 (1.12-4.71)). Educational level was not related to the probability of PtDA use. CONCLUSIONS: We accomplished a high level of PtDA use. Patients were more likely to use the PtDA if they received the link via the surgery department and if "to be discussed with the patient" was written in the multidisciplinary team report.

Risk communication in a patient decision aid for radiotherapy in breast cancer: How to deal with uncertainty?

BACKGROUND AND AIM: Patient decision aids for oncological treatment options, provide information on the effect on recurrence rates and/or survival benefit, and on side-effects and/or burden of different treatment options. However, often uncertainty exists around the probability estimates for recurrence/survival and side-effects which is too relevant to be ignored. Evidence is lacking on the best way to communicate these uncertainties. The aim of this study is to develop a method to incorporate uncertainties in a patient decision aid for breast cancer patients to support their decision on radiotherapy. METHODS: Firstly, qualitative interviews were held with patients and health care professionals. Secondly, in the development phase, thinking aloud sessions were organized with four patients and 12 health care professionals, individual and group-wise. RESULTS: Consensus was reached on a pictograph illustrating the whole range of uncertainty for local recurrence risks, in combination with textual explanation that a more exact personalized risk would be given by their own physician. The pictograph consisted of 100 female icons in a 10 x 10 array. Icons with a stepwise gradient color indicated the uncertainty margin. The prevalence and severity of possible side-effects were explained using verbal labels. CONCLUSIONS: We developed a novel way of visualizing uncertainties in recurrence rates in a patient decision aid. The effect of this way of communicating risk uncertainty is currently being tested in the BRASA study (NCT03375801).

Positive Health beyond boundaries in community care: design of a prospective study on the effects and implementation of an integrated community approach.

BACKGROUND: High healthcare expenditures due to population ageing and chronic complex health complaints are a challenge on a global scale. To improve the quality of healthcare, population health, and professionals' work satisfaction and to reduce healthcare costs (Quadruple Aim), the Dutch Ministry of Health, Welfare and Sport designated nine pioneer site regions across the Netherlands. One of these pioneer sites is the integrated community approach (ICA) known as 'Blue Care'. This article describes the design of a prospective study investigating the effects of Blue Care ICA on Quadruple Aim outcomes and a process evaluation focussing on its implementation in deprived neighbourhoods. METHODS: A mixed-methods approach, combining both quantitative and qualitative research methods, is applied to yield an enriched understanding of the various processes that will take place in the neighbourhoods. A prospective, quasi-experimental study is conducted within a natural experiment. Blue Care ICA is being implemented between 2017 and 2020 and research activities are taking place parallel to the implementation process. Effects of Blue Care ICA are measured at T0 (baseline), T1 (after 1 year), T2 (after 2 years) and at T3 (after 3 years) using a questionnaire. The primary outcome measure is health-related quality of life (SF-12v2), secondary outcomes are health status (EQ-5D-5 L), resilience (RS-Scale), Positive Health (Spiderweb diagram) and quality of care (grade 0-10). As part of the process evaluation, the Consolidated Framework for Implementation Research guided the formulation of process evaluation questions. Participant observations, interviews and focus groups with all stakeholders active in the Blue Care ICA will be conducted during the whole implementation period (2017-2020). DISCUSSION: The evaluation takes into account the interconnections between content, application, context and outcomes to understand how the Blue Care ICA unfolds over time in a complex, dynamic setting. Results of the effect and process evaluation will become available in 2020. TRIAL REGISTRATION: NTR 6543 , registration date; 25 July 2017.

Ten-year results of the PORTEC-2 trial for high-intermediate risk endometrial carcinoma: improving patient selection for adjuvant therapy.

BACKGROUND: PORTEC-2 was a randomised trial for women with high-intermediate risk (HIR) endometrial cancer, comparing pelvic external beam radiotherapy (EBRT) with vaginal brachytherapy (VBT). We evaluated long-term outcomes combined with the results of pathology review and molecular analysis. METHODS: 427 women with HIR endometrial cancer were randomised between 2002-2006 to VBT or EBRT. Primary endpoint was vaginal recurrence (VR). Pathology review was done in 97.4%, combined with molecular analysis. RESULTS: Median follow-up was 116 months; 10-year VR was 3.4% versus 2.4% for VBT vs. EBRT (p = 0.55). Ten-year pelvic recurrence (PR) was more frequent in the VBT group (6.3% vs. 0.9%, p = 0.004), mostly combined with distant metastases (DM). Ten-year isolated PR was 2.5% vs. 0.5%, p = 0.10, and DM 10.4 vs. 8.9% (p = 0.45). Overall survival for VBT vs. EBRT was 69.5% vs. 67.6% at 10 years (p = 0.72). L1CAM and p53-mutant expression and substantial lymph-vascular space invasion were risk factors for PR and DM. EBRT reduced PR in cases with these risk factors. CONCLUSION: Long-term results of the PORTEC-2 trial confirm VBT as standard adjuvant treatment for HIR endometrial cancer. Molecular risk assessment has the potential to guide adjuvant therapy. EBRT provided better pelvic control in patients with unfavourable risk factors.

[Substitution of care: what do we know, what should we know, and what should we do?] / Substitutie van zorg.

In order to contain rising healthcare expenditure, the Dutch minister of Health, Welfare, and Sport has agreed with various stakeholders to shift care as much as possible from the expensive specialised care sector to the cheaper primary care sector. Such a shift is only desirable if it constitutes a permanent shift to the primary care sector thereby reducing costs while simultaneously increasing quality of care and the health of the population. In order to prove the success of substitution initiatives, their effects must be compared with the national trend at population level. Longitudinal research is necessary as substitution constitutes a transitional process that requires continuous monitoring and interaction between patients, healthcare providers, insurers, and scientists.

Cost Effectiveness of Using Array-CGH for Diagnosing Learning Disability.

OBJECTIVE: To undertake a cost-effectiveness analysis of using microarray comparative genomic hybridisation (array-CGH) as a first-line test versus as a second-line test for the diagnosis of causal chromosomal abnormalities in patients referred to a NHS clinical genetics service in the U.K. with idiopathic learning disability, developmental delay and/or congenital anomalies. METHODS: A cost-effectiveness study was conducted. The perspective is that of a U.K. NHS clinical genetics service provider (with respect to both costs and outcomes). A cohort of patients (n = 1590) referred for array-CGH testing of undiagnosed learning disability and developmental delay by a single NHS regional clinical genetics service (South East Thames Regional Genetics Service), were split into a before-and-after design where 742 patients had array-CGH as a second-line test (before group-comparator intervention) and 848 patients had array-CGH as a first-line test (after group-evaluated intervention). The mean costs were calculated from the clinical genetics testing pathway constructed for each patient including the costs of genetic testing undertaken and clinical appointments scheduled. The outcome was the number of diagnoses each intervention produced so that a mean cost-per-diagnosis could be calculated. The cost effectiveness of the two interventions was calculated as an incremental cost-effectiveness ratio to produce an incremental cost-per-diagnosis (in 2013 GBP). Sensitivity analyses were conducted by altering both costs and effects to check the validity of the outcome. RESULTS: The incremental mean cost of testing patients using the first-line testing strategy was -GBP241.56 (95% CIs -GBP256.93 to -GBP226.19) and the incremental mean gain in the percentage diagnoses was 0.39% (95% CIs -2.73 to 3.51%), which equates to an additional 1 diagnosis per 256 patients tested. This cost-effectiveness study comparing these two strategies estimates that array-CGH first-line testing dominates second-line testing because it was both less costly and as effective. The sensitivity analyses conducted (adjusting both costs and effects) supported the dominance of the first-line testing strategy (i.e. lower cost and as effective). CONCLUSIONS: The first-line testing strategy was estimated to dominate the second-line testing strategy because it was both less costly and as effective. These findings are relevant to the wider UK NHS clinical genetics service, with two key strengths of this study being the appropriateness of the comparator interventions and the direct applicability of the patient cohort within this study and the wider UK patient population.

Vaccination of poultry workers: delivery and uptake of seasonal influenza immunization.

Avian influenza is a highly infectious disease in poultry and although the risk of human infection is low, concerns exist that it could evolve into a new human strain of pandemic potential if reassortment with a human influenza virus occurs. In January 2007, the UK government introduced a programme to vaccinate poultry workers to reduce the potential of such an event. This study evaluates the delivery, uptake and costs of the programme in three counties of England. A questionnaire survey was completed by consultants in public health in all the Primary Care Trusts in Norfolk, Suffolk and Cambridgeshire in May 2007. The delivery of the programme varied between Primary Care Trusts, including being delivered in some cases by clinics in primary care, by general practitioners and occupational health services in others. The uptake of vaccination was low ranging from 7% to 29% at a cost of £29 to £132 per person vaccinated. Vaccination of poultry workers as a public health measure to prevent an influenza pandemic is likely to be ineffective with the level of coverage found in this evaluation in our region.

Vaginal brachytherapy versus pelvic external beam radiotherapy for patients with endometrial cancer of high-intermediate risk (PORTEC-2): an open-label, non-inferiority, randomised trial.

BACKGROUND: After surgery for intermediate-risk endometrial carcinoma, the vagina is the most frequent site of recurrence. This study established whether vaginal brachytherapy (VBT) is as effective as pelvic external beam radiotherapy (EBRT) in prevention of vaginal recurrence, with fewer adverse effects and improved quality of life. METHODS: In this open-label, non-inferiority, randomised trial undertaken in 19 Dutch radiation oncology centres, 427 patients with stage I or IIA endometrial carcinoma with features of high-intermediate risk were randomly assigned by a computer-generated, biased coin minimisation procedure to pelvic EBRT (46 Gy in 23 fractions; n=214) or VBT (21 Gy high-dose rate in three fractions, or 30 Gy low-dose rate; n=213). All investigators were masked to the assignment of treatment group. The primary endpoint was vaginal recurrence. The predefined non-inferiority margin was an absolute difference of 6% in vaginal recurrence. Analysis was by intention to treat, with competing risk methods. The study is registered, number ISRCTN16228756. FINDINGS: At median follow-up of 45 months (range 18-78), three vaginal recurrences had been diagnosed after VBT and four after EBRT. Estimated 5-year rates of vaginal recurrence were 1.8% (95% CI 0.6-5.9) for VBT and 1.6% (0.5-4.9) for EBRT (hazard ratio [HR] 0.78, 95% CI 0.17-3.49; p=0.74). 5-year rates of locoregional relapse (vaginal or pelvic recurrence, or both) were 5.1% (2.8-9.6) for VBT and 2.1% (0.8-5.8) for EBRT (HR 2.08, 0.71-6.09; p=0.17). 1.5% (0.5-4.5) versus 0.5% (0.1-3.4) of patients presented with isolated pelvic recurrence (HR 3.10, 0.32-29.9; p=0.30), and rates of distant metastases were similar (8.3% [5.1-13.4] vs 5.7% [3.3-9.9]; HR 1.32, 0.63-2.74; p=0.46). We recorded no differences in overall (84.8% [95% CI 79.3-90.3] vs 79.6% [71.2-88.0]; HR 1.17, 0.69-1.98; p=0.57) or disease-free survival (82.7% [76.9-88.6] vs 78.1% [69.7-86.5]; HR 1.09, 0.66-1.78; p=0.74). Rates of acute grade 1-2 gastrointestinal toxicity were significantly lower in the VBT group than in the EBRT group at completion of radiotherapy (12.6% [27/215] vs 53.8% [112/208]). INTERPRETATION: VBT is effective in ensuring vaginal control, with fewer gastrointestinal toxic effects than with EBRT. VBT should be the adjuvant treatment of choice for patients with endometrial carcinoma of high-intermediate risk. FUNDING: Dutch Cancer Society.

Substitution of specialized rheumatology nurses for rheumatologists in the diagnostic process of fibromyalgia: a randomized controlled trial.

OBJECTIVE: To evaluate the substitution of specialized rheumatology nurses for rheumatologists in diagnosing fibromyalgia (FM). METHODS: Referred patients with FM symptoms (n = 193) were randomized to a study group diagnosed by a specialized rheumatology nurse (SRN group, n = 97) or to a control group diagnosed by a rheumatologist (RMT group, n = 96). SRN patients were seen within 3 weeks by a nurse who took structured history and initiated routine laboratory tests. During a 5-minute supervision session, the rheumatologist was informed by the nurse about medical history, performed a brief physical examination, and confirmed or rejected the nurse's diagnosis. RMT patients were seen by a rheumatologist after a regular waiting period of 3 months. Outcome measures were initial agreement between the nurse and rheumatologist in the SRN group, final diagnosis after 12-24 months of followup, patient satisfaction, and diagnostic costs. RESULTS: The mean waiting time after randomization was 2.8 and 12.1 weeks in the SRN and RMT groups, respectively. Eight RMT patients cancelled their appointments because of the waiting time. Excellent agreement (kappa = 0.91) between rheumatologists and nurses was found. After 12-24 months of followup, none of the initial diagnoses were recalled in either group. SRN patients were significantly more satisfied than RMT patients. Mean diagnostic costs were lower in the SRN group (euro219) than in the RMT group (euro281) (95% uncertainty interval euro-103, euro-20). CONCLUSION: Substituting specialized nurses for rheumatologists in the diagnostic process of FM is a trustworthy and successful approach that saves waiting time, provides greater patient satisfaction, and is cost-effective.

Envelope protein requirements for the assembly of infectious virions of porcine reproductive and respiratory syndrome virus.

Virions of porcine reproductive and respiratory syndrome virus (PRRSV) contain six membrane proteins: the major proteins GP5 and M and the minor proteins GP2a, E, GP3, and GP4. Here, we studied the envelope protein requirements for PRRSV particle formation and infectivity using full-length cDNA clones in which the genes encoding the membrane proteins were disrupted by site-directed mutagenesis. By transfection of RNAs transcribed from these cDNAs into BHK-21 cells and analysis of the culture medium using ultracentrifugation, radioimmunoprecipitation, and real-time reverse transcription-PCR, we observed that the production of viral particles is dependent on both major envelope proteins; no particles were released when either the GP5 or the M protein was absent. In contrast, particle production was not dependent on the minor envelope proteins. Remarkably, in the absence of any one of the latter proteins, the incorporation of all other minor envelope proteins was affected, indicating that these proteins interact with each other and are assembled into virions as a multimeric complex. Independent evidence for such complexes was obtained by coexpression of the minor envelope proteins in BHK-21 cells using a Semliki Forest virus expression system. By analyzing the maturation of their N-linked oligosaccharides, we found that the glycoproteins were each retained in the endoplasmic reticulum unless expressed together, in which case they were collectively transported through the Golgi complex to the plasma membrane and were even detected in the extracellular medium. As the PRRSV particles lacking the minor envelope proteins are not infectious, we hypothesize that the virion surface structures formed by these proteins function in viral entry by mediating receptor binding and/or virus-cell fusion.

Significance of the oligosaccharides of the porcine reproductive and respiratory syndrome virus glycoproteins GP2a and GP5 for infectious virus production.

The arterivirus porcine reproductive and respiratory syndrome virus (PRRSV) contains four glycoproteins, GP(2a), GP(3), GP(4) and GP(5), the functions of which are still largely unresolved. In this study, the significance of the N-glycosylation of the GP(2a) and GP(5) proteins of PRRSV strain LV was investigated. Both glycoproteins contain two predicted N-glycosylation sites that are highly conserved between North American-type and European-type PRRSV. Using site-directed mutagenesis, single and double mutant full-length PRRSV cDNA clones were generated. After analysing the expression of the mutant proteins and the actual use of the four putative glycosylation sites in the wild-type proteins, the production of mutant virus particles and their infectivities were investigated. The results showed that the N-linked glycans normally present on the GP(2a) protein are not essential for particle formation, as is the oligosaccharide attached to N53 of the GP(5) protein. In contrast, the oligosaccharide linked to N46 of the GP(5) protein is strongly required for virus particle production. The specific infectivities of the mutant viruses were investigated by comparing their infectivity-per-particle ratios with that of wild-type virus. The results showed that the lack of either one or both of the N-linked oligosaccharides on GP(2a) or of the oligosaccharide attached to N53 of GP(5) did not significantly affect the infectivities of the viruses. In contrast, the two recombinant viruses lacking the oligosaccharide bound to N46 exhibited a significantly reduced specific infectivity compared with the wild-type virus. The implications of the differential requirements of the modifications of GP(2a) and GP(5) for PRRSV assembly and infectivity are discussed.

Primary open angle glaucoma. The need for a consensus case definition.

Primary open angle glaucoma is an important cause of visual impairment and blindness in the United Kingdom. This paper gives a brief overview of the condition and its management. It presents evidence of the continued absence of a consensus case definition for this condition. This has resulted in considerable uncertainty about what is diagnosed and treated as primary open angle glaucoma. The important negative effects of this situation are outlined. These include the impact on the person wrongly diagnosed with the condition, the uncertainties both for commissioning and provision of clinical healthcare services, and the lack of a firm basis for research into the condition. It is argued that there is an urgent need to resolve this problem to improve the health of the population.

Safety and protective efficacy of porcine reproductive and respiratory syndrome recombinant virus vaccines in young pigs.

Three porcine reproductive and respiratory syndrome virus (PRRSV) recombinants, generated by mutagenesis of an infectious cDNA clone of the Lelystad virus (LV) isolate, were tested for their safety and protective efficacy as potential PRRSV vaccines in pigs. Recombinant vABV688 contains two amino acid substitutions in the minor structural protein GP(2) resulting in improved growth on cell line CL2621; in recombinant vABV707 the region encoding the ectodomain of the major unglycosylated membrane protein M has been replaced by that of the murine lactate dehydrogenase-elevating arterivirus; recombinant vABV746 lacks the six C-terminal amino acids of the nucleocapsid protein N. First, we determined the safety of these recombinant viruses by monitoring the stability of the introduced mutations in 8-week-old pigs. We showed that the introduced genomic mutations were maintained throughout the viraemic period. Second, the protective efficacy of immunization with the recombinant viruses against challenge with a homologous and a heterologous PRRSV strain was determined in two pigs and compared with the efficacy of vABV437, a virus derived from the parental LV cDNA. The viraemia in pigs immunized with the recombinant viruses was reduced compared to pigs immunized with vABV437. In addition, the length of viraemia was reduced in the sentinel pigs that were introduced into the groups immunized with vABV746, vABV688, and vABV707, however, all of the sentinel pigs became infected. Pigs immunized with vABV707 and vABV437 were protected against challenge with homologous virus LV-Ter Huurne and transmission of the latter virus. None of the immunized pigs were protected against heterologous challenge with the virulent US isolate SDSU#73, but the vABV707- and vABV746-immunized pigs were protected against transmission of this virus from challenged pigs. In conclusion, the obtained viral recombinants are interesting candidates to be further explored for their use as vaccines against PRRSV.