Exploring determinants of antimicrobial prescribing behaviour using the Theoretical Domains Framework

BACKGROUND

Few theoretically-based, qualitative studies have explored determinants of antimicrobial prescribing behaviour in hospitals. Understanding these can promote successful development and implementation of behaviour change interventions (BCIs).

OBJECTIVE

(s): To use the Theoretical Domains Framework (TDF) to explore determinants of clinicians' antimicrobial prescribing behaviour, identifying barriers (i.e., impediments) and facilitators to appropriate antimicrobial practice.

METHODS

Semi-structured interviews with purposively-sampled doctors and pharmacists with a wide range of specialties and expertise in Hamad Medical Corporation hospitals in Qatar. Interviews based on previous quantitative research and the TDF were audio-recorded, transcribed and independently analysed by two researchers using the TDF as an initial coding framework.

RESULTS

Data saturation was achieved after interviewing eight doctors and eight pharmacists. Inter-related determinants of antimicrobial prescribing behaviour linked to ten TDF domains were identified as barriers and facilitators that may contribute to inappropriate or appropriate antimicrobial prescribing. The main barriers identified were around hospital guidelines and electronic system deficiencies (environmental context and resources); knowledge gaps relating to guidelines and appropriate prescribing (knowledge); restricted roles/responsibilities of microbiologists and pharmacists (professional role and identity); challenging antimicrobial prescribing decisions (memory, attention and decision processes); and professional hierarchies and poor multidisciplinary teamworking (social influences). Key facilitators included guidelines compliance (goals and intentions), and participants' beliefs about the consequences of appropriate or inappropriate prescribing. Further education and training, and some changes to guidelines including their accessibility were also considered essential.

CONCLUSIONS

Antimicrobial prescribing behaviour in hospitals is a complex process influenced by a broad range of determinants including specific barriers and facilitators. The in-depth understanding of this complexity provided by this work may support the development of an effective BCI to promote appropriate antimicrobial stewardship.

Implementation frameworks for polypharmacy management within healthcare organisations: a scoping review

BACKGROUND

Several guidelines support polypharmacy management in individual patients. More organisational-level focus is needed on the use of implementation frameworks.

AIM

To characterise the peer reviewed literature on implementation frameworks, focussing on barriers and facilitators to implementation at organisational level in the context of polypharmacy management.

METHOD

A scoping review protocol was devised, supporting retrieval of studies published in English, reporting from any sector of practice. Medline, International Pharmaceutical Abstracts, Cumulative Index of Nursing and Allied Health Literature and Business Source Complete were searched to January 2022 using Medical Subject Headings including: 'polypharmacy', 'deprescriptions', 'strategic planning' and 'organizational innovation'. A narrative approach to data synthesis was applied. Searching, data extraction and synthesis were undertaken independently by two reviewers.

RESULTS

After screening 797 records eight papers remained. Two were descriptive outlining details of specific initiatives, six used qualitative methods to explore determinants for implementation including barriers and enablers. Organisation level barriers included: poor organisational culture with a lack of sense of urgency and national plans, resource availability and communication issues including patient information and at transitions of care. Organisational facilitators included availability of government funding and regulatory environment promoting patient safety, a national emphasis on quality of care for older adults, co-ordinated national efforts and local evidence.

CONCLUSION

Limited literature focusses on the use of implementation frameworks at organisational levels. This review highlights the need for further work on implementation frameworks in this context to help achieve effective organisational change.

Designated prescribing practitioners: a theory-based cross-sectional study of stakeholders' views on implementation of a novel pharmacy regulator mandated preceptorship model

BACKGROUND

Scottish Government is increasing independent prescribers (IP) in community pharmacy (CP). A new preceptorship model using IPs as Designated Prescribing Practitioners (DPPs) has been introduced.

AIM

To investigate stakeholder views of implementation of a novel regulator mandated IP course preceptorship model.

METHOD

A theory-based online pre-piloted survey of stakeholders including e.g. directors of pharmacy, prescribing, education leads, policy & strategy leads and CPs. Questionnaire development used Consolidated Framework for Implementation Research (CFIR) and a DPP Competency Framework. Data were analysed descriptively and presented with mapping to CFIR constructs.

RESULTS

Of ninety-nine responses 82.5% (80/97) responded 'yes' to '..abilities in reporting concerns..' and 53.1% (51/96) indicating 'no' to '..anticipated issues with clinical and diagnostic skills'. CFIR related facilitators included agreement that; there was tension for change with 84 (85%) indicating '….urgent need to implement role …', that incentives are likely to help (6566%) and small pilots would help (8588%). Barriers were evident related to 'unsure' responses about sufficiency of; DPP capacity (39/97, 40.2%), time (48/96, 50%) and support and resources (4445%) to undertake the role. Concerns were expressed with 81 (83%) in agreement or unsure that leadership commitment may be lacking and 48 (48.9%) were 'unsure' about availability of good training for the DPP role.

CONCLUSION

There was DPP role positivity but expressed barriers and facilitators at policy, organisational and individual practitioner levels needing further consideration. Further research is warranted on uptake and embedding of the role.

Views and perceptions on the designated prescribing practitioner role, barriers, and facilitators for its implementation in community pharmacy: a theory-based quantitative study

Introduction

Scottish Government aims to increase numbers of pharmacist independent prescribers (IP) in community to improve healthcare access. This includes utilising qualified IPs as Designated Prescribing Practitioners (DPP) to increase capacity to supervise pharmacists on IP courses.

Aim

To investigate views and perceptions of practice-based stakeholders and identify potential influences on DPP implementation for Scottish community pharmacists (CP)

Methods

A theory-based cross-sectional online survey of stakeholders involved in DPP role implementation (e.g. Directors of Pharmacy, Prescribing Leads, IP qualified CPs) was employed. Participation invites were shared with Scottish health boards and CP organisations via email and social media. Snowball sampling was used so no key individual was omitted. The questionnaire was informed by Royal Pharmaceutical Society (RPS) DPP Framework (1) and Consolidated Framework for Implementation Research (2). It examined views and awareness of DPP role, implementation drivers, and obstacles. The tool was reviewed for credibility and dependability then piloted. Data were analysed descriptively.

Results

Ninety-nine responses were received (NB: Since this was a national survey of multiple stakeholders without a defined sample list, response rate was indeterminate). Two-fifths (n=39, 40.2%) were community pharmacists with majority qualified for more than 10 years (n=76, 76.8%). Only 18 had previous involvement with IP courses. The table shows awareness and views of the role based on RPS framework. Respondents had positive attitudes to DPP implementation with the majority supporting it (72, 73.5%) and believing that its advantages outweigh any disadvantages (74, 75.5%). Facilitators of successful implementation were having clearly defined leadership roles (89, 90.9%), piloting (85, 87.6%), and incentives (65, 88.8%). Drivers for uptake of role included improving patient care (94, 96%) and the profession (91, 92.8%), self-development (91, 92.8%), developing individual pharmacists (89, 90.8%), payment (77, 79.4%), and being recognised by peers/employers (73, 75.2%).

Conclusion

There was positivity regarding DPP role, its acceptability in, and advantages for CP. Resource-related concerns were expressed that need further consideration to ensure effective implementation. This is the first study internationally to explore views on DPP role. Given the Scottish focus, findings may lack generalisability. Future research should focus on theory-based evaluation of structures and processes of implementation.

References

(1) Royal Pharmaceutical Society. Designated Prescribing Practitioner Competency Framework [internet]. London: Royal Pharmaceutical Society; 2019 [Cited 28/09/2021]. Available from: https://www.rpharms.com/resources/frameworks/designated-prescribing-practitioner-competency-framework

(2) Damschroder LJ, Aron DC, Keith RE, Kirsh SR, Alexander JA, Lowery JC. Fostering implementation of health services research findings into practice: a consolidated framework for advancing implementation science. Implement Sci. 2009;4:50.

Development and implementation of strategic frameworks for polypharmacy management in healthcare organisations: a scoping review

Introduction

‘Polypharmacy management’ (PM) guidelines exist (1) but there are challenges to implementation and WHO recommends theory-based organisational change strategies to address this (2).

Aim

To identify current evidence base around the development and implementation of strategic frameworks for polypharmacy management in healthcare organisations.

Methods

The Arksey and O’Malley framework and the PRISMA Scoping Reviews extension were used. Databases (Medline, IPA, CINAHL and Business Source Complete) were searched to December 2020. After title and abstract screening full text articles were reviewed. Search, data extraction and eligibility criteria were defined (table). Included studies were charted to collate extracted information and a descriptive narrative approach to data synthesis was taken. All steps involved independent checks by two team members with disagreement mediation by a third.

Results

Initially 702 records were identified after removal of duplicates, 632 of these were excluded after screening leaving 70 papers. A further 63 of these 70 papers were excluded after full text review. The seven papers remaining met the eligibility criteria fully and showed: despite wide availability of polypharmacy guidelines in the West, particularly the UK and European Union, there is limited evidence on the strategic development and implementation of PM frameworks. The main characteristics of strategic approaches used included: Kotter’s eight step process for organisational change, theoretical domains framework to identify individual behavioural determinants, and a community-based medication management intervention. Reported barriers were: lack of data to create a sense of urgency, lack of a national plan for implementation, monitoring and evaluation, poor coordination of care, lack of time for staff, unclear allocation of tasks and responsibilities and lack of training. Organisational level facilitators included: government funding streams and strict regulatory environment, national emphasis on quality and presence of contextual evidence.

Conclusion

Despite PM guidance this review shows limited evidence on development of theory based strategic frameworks for organisational change. Evidence was from Western contexts only. A strength of this work is that it searched internationally but was limited by exclusion of grey literature. Further work is required on theory based strategic organisational change in PM particularly in contexts out with the Western world.

References

(1) Mair A, Fernandez-Llimos F, Alonso A, Harrison C, Hurding S, Kempen T, Kinnear M, Michael N, McIntosh J, Wilson M, the SIMPATHY Consortium. Polypharmacy Management by 2030: a patient safety challenge. 2nd edition. Coimbra: SIMPATHY Consortium; 2017.

(2) World Health Organization. Medication safety in polypharmacy: technical report. Geneva: World Health Organization; 2019.

Using the Theoretical Domains Framework to investigate clinicians’ behavioural determinants of antimicrobial prescribing in Qatar

Introduction

A recent systematic review by Talkhan et al demonstrated the need for theoretically based behaviour change interventions in this area. [1] For development of such complex interventions, emphasis should be placed on using theory to systematically identify behavioural determinants of antimicrobial prescribing.

Aim

To identify and quantify clinicians’ behavioural determinants of antimicrobial prescribing in Qatar.

Methods

This cross-sectional survey is part of a multi-phase explanatory, sequential mixed methods PhD project in Qatar. Questionnaires were distributed (online and paper based) to all doctors (~4,000) and pharmacists (~400) within Hamad Medical Corporation (HMC, the main healthcare provider). The questionnaire was developed with reference to the Determinants of Implementation Behaviour Questionnaire (a generic questionnaire derived from the 14 theoretical domains of the Theoretical Domains Framework, TDF). [2] Each item was presented as a 5-point Likert scale (scored 5=Strongly agree to 1=Strongly disagree). Personal and practice demographics were also collected for data contextualisation. The draft questionnaire was reviewed for face/content validity by an expert panel of six researchers in Qatar and the UK with experience in the use of the TDF, followed by ‘Think aloud’ testing and piloting. Analysis investigated the behavioural determinants and influential factors through descriptive, principal component analysis (PCA) and inferential analysis. Ethics approval was granted from a UK university and HMC.

Results

In total, 535 responses were received, 339 (63.4%) from doctors and 196 (36.6%) from pharmacists. Respondents were predominantly male, 346 (64.7%). Just over half (n=285, 53.3%) had ≤ 5 years’ experience as health professionals. PCA showed a three component (C) solution with components incorporating a number of questionnaire items labelled: ‘Guidelines compliance’ (C1 with 8 items), ‘Influences on prescribing’ (C2 with 7 items) and ‘Self-efficacy’ (C3 with 5 items) in prescribing/recommendation activity. A scale score for each respondent was calculated through summation of Likert scores for the relevant questionnaire items within each component. These scales had high internal reliability (Cronbach’s alpha all >0.7) showing consistency in response between component items indicating statistical appropriateness for developing scales. The median score (possible scale range, midpoint) for each scale was C1, 32 (8 to 40, 24), C2, 26 (7 to 35, 21) and C3, 20, (5 to 25, 15). By way of example Table 1 shows levels of agreement for items in C2. This shows lower levels of agreement than C1 scale with the median scale score (26) closer to the midpoint (21) indicating that respondents had less positive views. Inferential analysis using these scale scores and free text analysis is in progress.

Conclusion

A theoretical basis was used throughout providing insights to behavioural determinants for the development of a theory-based behaviour change intervention. Preliminary results suggest that social influences, staff development and quality monitoring may be useful targets for behaviour change interventions to improve antimicrobial prescribing practice. Limitations include potential social desirability bias and focus on one healthcare organisation/country in the Middle East which may limit generalisability of findings. More in-depth exploration is required to select and test appropriate linked theory-based behaviour change techniques.

References

1. Talkhan H, Stewart D, McIntosh T, Ziglam H Palli Valapila, A; Moza Sulaiman H, Diab M, Cunningham S. The use of theory in the development and evalu​ation of behaviour change interventions to improve antimicrobial prescribing: a systematic review. J Antimicrob Chemother. 2020;75(9):2394–2410, Available from https://doi.org/10.1093/jac/dkaa154 [Accessed 12 Oct 2020].

2. Huijg JM, Gebhardt WA, Dusseldorp E, Verheijden MW, van der Zouwe N, Middelkoop BJ, Crone MR. Measuring determinants of implementation behaviour: psychometric properties of a questionnaire based on the Theoretical Domains Framework. Implement. Sci. 2014;9(1):33.

Piloting the United Kingdom 'Prescribing Safety Assessment' with pharmacist prescribers in Scotland

BACKGROUND

Prescribing is a complex task requiring considerable knowledge and skills. The Prescribing Safety Assessment (PSA) was developed by the British Pharmacological Society and the United Kingdom (UK) Medical Schools Council. Between February and June 2014, over 7000 final year medical students undertook the PSA, with an overall pass rate of 94%. Independent prescribing for suitably trained pharmacists was introduced in the UK in 2006. To date there has been little focus on any objective measures of prescribing safety.

OBJECTIVE

To determine the PSA performance of a pilot group of pharmacist prescribers in Scotland relative to medical students and to test the feasibility and acceptability of running the PSA.

METHODS

A group of 59 pharmacist prescribers took part in ten events. The PSA consisted of 30 questions to be completed over 60 min. All questions had been used in the 2014 assessments for final year medical students. The PSA was undertaken online under invigilated conditions, mirroring the medical student assessment. One month later, participants were invited to complete an online evaluation questionnaire.

RESULTS

The mean overall PSA scores (±SD) were 87.5% ± 8.7 (range 52-98) compared to a 88.5% for medical students. Based on an Angoff passmark of 76.0%, 53 pharmacists (89.8%) passed compared to an overall pass rate in PSA 2014 of 94%. Pharmacists performed equivalently to medical students in all assessment areas, with a slightly lower performance in the prescribing, drug monitoring and data interpretation questions offset by better performance in prescription review and adverse drug reactions. Feedback was positive in relation to appropriateness, relevance and level of difficulty of the PSA although several commented that they were practicing in very specific clinical areas.

CONCLUSION

These pilot events have benchmarked the PSA performance of pharmacist prescribers with final year medical students, and feedback confirmed feasibility and acceptability.

Influences on prescribing decision-making among non-medical prescribers in the United Kingdom: systematic review

BACKGROUND

Suitably qualified non-medical healthcare professionals may now prescribe medicines. Prescribing decision-making can be complex and challenging; a number of influences have been identified among medical prescribers but little appears to be known about influences among non-medical prescribers (NMPs).

OBJECTIVE

To critically appraise, synthesize and present evidence on the influences on prescribing decision-making among supplementary and independent NMPs in the UK.

METHODS

The systematic review included all studies between 2003 and June 2013. Included studies researched the prescribing decision-making of supplementary and independent NMPs practising in the UK; all primary and secondary study designs were considered. Studies were assessed for quality and data extracted independently by two researchers, and findings synthesized using a narrative approach.

RESULTS

Following duplicates exclusion, 886 titles, 349 abstracts and 40 full studies were screened. Thirty-seven were excluded leaving three for quality assessment and data extraction. While all studies reported aspects of prescribing decision-making, this was not the primary research aim for any. Studies were carried out in primary care almost exclusively among nurse prescribers (n = 67). Complex influences were evident such as experience in the role, the use of evidence-based guidelines and peer support and encouragement from doctors; these helped participants to feel more knowledgeable and confident about their prescribing decisions. Opposing influences included prioritization of experience and concern about complications over evidence base, and peer conflict.

CONCLUSION

While there is a limited evidence base on NMPs' prescribing decision-making, it appears that this is complex with NMPs influenced by many and often opposing factors.

A qualitative study of UK pharmacy pre-registration graduates' views and reflections on pharmacist prescribing

Background

Pre-registration pharmacy graduates are a key group in relation to developing and implementing innovations in practice.

Objective

To explore the views and reflections on pharmacist prescribing of UK pre-registration pharmacy graduates.

Method

Semi-structured telephone interviews with a sample (n = 12) of pre-registration pharmacy graduates.

Key findings

Most reported a desire to train as prescribers, largely for reasons of professional development, but acknowledged the need first to develop as pharmacists. They perceived the lack of organisational strategy, pharmacist prescribers' self-confidence and additional workload to be barriers and were aware of the value of interprofessional relationships as potential facilitators to pharmacist prescribing.

Conclusion

While participants were supportive of pharmacist prescribing, they highlighted the need first to gain experience as pharmacists and were acutely aware of barriers to prescribing implementation.

A cross sectional survey of the views of newly registered pharmacists in Great Britain on their potential prescribing role: a cautious approach

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Pharmacists, along with certain other health professionals, may train and practice as supplementary or independent prescribers. The implementation and sustainability of pharmacist prescribing services throughout Britain will require a sizeable workforce. However, a survey of GB pharmacists highlighted that only a minority has taken any action to investigate prescribing training. Newly registered pharmacists may be keen to explore extended clinical roles and their engagement is likely to be key to the future success of this initiative.

WHAT THIS STUDY ADDS

Newly registered pharmacists are cautious in their approach to taking on prescribing training and roles. While almost all expressed interest in prescribing training, they acknowledged training needs in clinical examination, patient monitoring and medico-legal aspects of prescribing. Longitudinal research on a cohort of newly registered pharmacist prescribers is warranted, aiming to identify later prescribing training actions and subsequent impact on patient care. AIM To investigate newly registered pharmacists' awareness of pharmacist prescribing and views on potential future roles as prescribers.

METHODS

A mailed questionnaire was sent to all 1658 pharmacists joining the Pharmacist Register in 2009.

RESULTS

The response rate was 25.2% (n= 418). While most (86.4%) expressed interest in prescribing training, they acknowledged training needs in clinical examination, patient monitoring and medico-legal aspects of prescribing. Two thirds of respondents (66.3%) thought the current requirement of being registered as a pharmacist for 2 years prior to commencing prescribing training was appropriate.

CONCLUSION

Newly registered pharmacists are cautious in their approach to taking on prescribing training and roles.

Age-dependent synuclein pathology following traumatic brain injury in mice

Synucleins (Syn), a family of synaptic proteins, includes alpha-Syn, which plays a pivotal role in Parkinson's disease and related neurodegenerative diseases (synucleinopathies) by forming distinct brain pathologies (Lewy bodies and neurites). Since traumatic brain injury (TBI) is a poorly understood risk factor for Parkinson's disease, we examined the effects of TBI in the young and aged mouse brain on alpha-, beta-, and gamma-Syn. Immunohistochemical analysis showed that brains from sham-injured young and aged mice had normal alpha- and beta-Syn immunoreactivity (IR) in neuropil of cortex, striatum, and hippocampus with little or no gamma-Syn IR. At 1 week post TBI, the aged mouse brain showed a transient increase of alpha- and beta-Syn IR in the neuropil as well as an induction of gamma-Syn IR in subcortical axons. This was associated with strong labeling of striatal axon bundles by antibodies to altered or nitrated epitopes in alpha-Syn as well as by antibodies to inducible nitric oxide synthase. However, these TBI-induced changes disappeared by 16 weeks post TBI, and altered Syn IR was not seen in young mice subjected to TBI nor in alpha-Syn knockout mice while Western blots confirmed that TBI induced transient alterations of alpha-Syn in the mouse brains. This model of age-dependent TBI-induced transient alterations in alpha-Syn provides an opportunity to examine possible links between TBI and mechanisms of disease in synucleinopathies.

The sequence of the human genome

A 2.91-billion base pair (bp) consensus sequence of the euchromatic portion of the human genome was generated by the whole-genome shotgun sequencing method. The 14.8-billion bp DNA sequence was generated over 9 months from 27,271,853 high-quality sequence reads (5.11-fold coverage of the genome) from both ends of plasmid clones made from the DNA of five individuals. Two assembly strategies-a whole-genome assembly and a regional chromosome assembly-were used, each combining sequence data from Celera and the publicly funded genome effort. The public data were shredded into 550-bp segments to create a 2.9-fold coverage of those genome regions that had been sequenced, without including biases inherent in the cloning and assembly procedure used by the publicly funded group. This brought the effective coverage in the assemblies to eightfold, reducing the number and size of gaps in the final assembly over what would be obtained with 5.11-fold coverage. The two assembly strategies yielded very similar results that largely agree with independent mapping data. The assemblies effectively cover the euchromatic regions of the human chromosomes. More than 90% of the genome is in scaffold assemblies of 100,000 bp or more, and 25% of the genome is in scaffolds of 10 million bp or larger. Analysis of the genome sequence revealed 26,588 protein-encoding transcripts for which there was strong corroborating evidence and an additional approximately 12,000 computationally derived genes with mouse matches or other weak supporting evidence. Although gene-dense clusters are obvious, almost half the genes are dispersed in low G+C sequence separated by large tracts of apparently noncoding sequence. Only 1.1% of the genome is spanned by exons, whereas 24% is in introns, with 75% of the genome being intergenic DNA. Duplications of segmental blocks, ranging in size up to chromosomal lengths, are abundant throughout the genome and reveal a complex evolutionary history. Comparative genomic analysis indicates vertebrate expansions of genes associated with neuronal function, with tissue-specific developmental regulation, and with the hemostasis and immune systems. DNA sequence comparisons between the consensus sequence and publicly funded genome data provided locations of 2.1 million single-nucleotide polymorphisms (SNPs). A random pair of human haploid genomes differed at a rate of 1 bp per 1250 on average, but there was marked heterogeneity in the level of polymorphism across the genome. Less than 1% of all SNPs resulted in variation in proteins, but the task of determining which SNPs have functional consequences remains an open challenge.

Effect of chain length and unsaturation on elasticity of lipid bilayers

Micropipette pressurization of giant bilayer vesicles was used to measure both elastic bending k(c) and area stretch K(A) moduli of fluid-phase phosphatidylcholine (PC) membranes. Twelve diacyl PCs were chosen: eight with two 18 carbon chains and degrees of unsaturation from one double bond (C18:1/0, C18:0/1) to six double bonds per lipid (diC18:3), two with short saturated carbon chains (diC13:0, diC14:0), and two with long unsaturated carbon chains (diC20:4, diC22:1). Bending moduli were derived from measurements of apparent expansion in vesicle surface area under very low tensions (0.001-0.5 mN/m), which is dominated by smoothing of thermal bending undulations. Area stretch moduli were obtained from measurements of vesicle surface expansion under high tensions (>0.5 mN/m), which involve an increase in area per molecule and a small-but important-contribution from smoothing of residual thermal undulations. The direct stretch moduli varied little (< +/-10%) with either chain unsaturation or length about a mean of 243 mN/m. On the other hand, the bending moduli of saturated/monounsaturated chain PCs increased progressively with chain length from 0.56 x 10(-19) J for diC13:0 to 1.2 x 10(-19) J for diC22:1. However, quite unexpectedly for longer chains, the bending moduli dropped precipitously to approximately 0.4 x 10(-19) J when two or more cis double bonds were present in a chain (C18:0/2, diC18:2, diC18:3, diC20:4). Given nearly constant area stretch moduli, the variations in bending rigidity with chain length and polyunsaturation implied significant variations in thickness. To test this hypothesis, peak-to-peak headgroup thicknesses h(pp) of bilayers were obtained from x-ray diffraction of multibilayer arrays at controlled relative humidities. For saturated/monounsaturated chain bilayers, the distances h(pp) increased smoothly from diC13:0 to diC22:1 as expected. Moreover, the distances and elastic properties correlated well with a polymer brush model of the bilayer that specifies that the elastic ratio (k(c)/K(A))(1/2) = (h(pp) - h(o))/24, where h(o) approximately 1 nm accounts for separation of the headgroup peaks from the deformable hydrocarbon region. However, the elastic ratios and thicknesses for diC18:2, diC18:3, and diC20:4 fell into a distinct group below the correlation, which showed that poly-cis unsaturated chain bilayers are thinner and more flexible than saturated/monounsaturated chain bilayers.

Genetic approaches to neurotrauma research: opportunities and potential pitfalls of murine models

Genetic strategies provide new ways to define the molecular cascades that regulate the responses of the mammalian nervous system to injury. Genetic interventions also provide opportunities to manipulate and control key molecular steps in these cascades, so as to modify the outcome of CNS injury. Most current genetic strategies involve the use of mice, an animal that has not heretofore been used extensively for neurotrauma research. Therefore, one purpose of the present review is to consider how mice respond to neural trauma, focusing especially on recent information that reveals important differences between mice and rats, and between different inbred strains of mice. The second aim of this review is to provide a brief introduction to the opportunities, caveats, and potential pitfalls of studies that use genetically modified animals for neurotrauma research.

Magnetic resonance imaging analysis of lumbar disc changes below scoliosis fusions. A prospective study

STUDY DESIGN

The authors of this prospective study examined the preoperative and 3-year postoperative magnetic resonance images of 14 patients undergoing anterior and posterior fusion and/or posterior fusion only for scoliosis. All magnetic resonance images were ready by two independent neuroradiologists, who were blinded to the purposes of the study, for the presence of disc narrowing, signal decrease on T2, or herniated nucleus pulposus before and after surgery. Particular attention was paid to the disc changes at the level directly below the end vertebral level of the fusion and two levels below the fusion in the lumbosacral spine existing before surgical intervention.

OBJECTIVES

To evaluate the potential for disc degeneration distal to long scoliosis fusions with end fusion levels in the mid to lower lumbar spine.

SUMMARY OF BACKGROUND DATA

The determination of end levels of fusion for contructs presently used to manage adult scoliotic deformity has been evaluated in terms of correction of curvature and late decompensation in coronal and sagittal plane balance after fusion. However, the natural history of the caudal, free-motion segments in terms of degeneration and/or correlation with pain has not yet been addressed.

METHODS

Fourteen patients undergoing scoliosis fusion underwent magnetic resonance imaging before surgery and approximately 3 years after surgery. The scans were reviewed by two independent neuroradiologists who looked at three degenerative indices at the disc below the area of scoliosis fusion. The authors analyzed rates of change of the three degenerative indices in the pre- and postoperative magnetic resonance images and created associations between the observed changes on the magnetic resonance images and the clinical outcomes of pain, the presence or absence of solid fusion, and the need for repeat surgery.

RESULTS

Estimates of the rates of change of the three degenerative indices one or two levels below the fusion were as follow: the chance of disc narrowing, .2-34%; the chance of a decreasing signal on T2, 5-54%, with a 23% incidence among this group; and the chance of herniated nucleus pulposus, 0-34%. There was a significant correlation between the presence of back and/or leg pain and the signal decrease one level below the fusion (P = .04).

CONCLUSIONS

If these results are corroborated in a larger sample size, surgeons who manage deformity may have to consider altering fusion levels at the time of fusion based on magnetic resonance imaging predictors. The present data may help to inform patients about the risk of developing junctional degenerative changes and potential symptoms from these changes below scoliosis fusions.

Impact acceleration injury in the rat: evidence for focal axolemmal change and related neurofilament sidearm alteration

Recently we reported that traumatic brain injury evokes local changes in the axolemma's permeability, in concert with local cytoskeletal changes involving neurofilament (NF) compaction and sidearm loss, all of which contribute to the genesis of reactive axonal change. Since it was of concern that these events may be either injury model- or species-specific, we sought to address these phenomena in a different but well-characterized animal model and species. Further, to provide more compelling insight into the potential for NF compaction and sidearm alteration, we also employed antibodies specific for the NF rod domains, which are readily visualized only when the NF sidearms are disturbed. Rats were subjected to impact acceleration injury. To assess the potential for altered axolemmal permeability, 5 animals received intrathecal horseradish peroxidase (HRP), normally excluded by the intact axolemma. To assess the potential for NF sidearm alteration, another 14 animals were processed for the visualization of antibodies targeting the NF rod domain at 5 minutes (min) to 24 hours (h) postinjury. All animals were evaluated at the LM and EM levels. Those animals receiving intrathecal HRP showed immediate focal alterations in the axolemma's permeability to the normally excluded tracer. Over a 2 h period, these axons demonstrated NF compaction. Antibodies targeted to the rod domains revealed focal intra-axonal immunoreactivity in sites closely correlated with those showing altered axolemmal permeability. These same sites also demonstrated evidence of NF compaction and sidearm loss/perturbation. Collectively, these findings suggest that occurrence of altered axolemmal permeability and concomitant cytoskeletal change are features common to traumatic brain injury in various animal models and species. Further, these studies underscore the utility of antibodies targeting the rod domain for the early detection of traumatically induced reactive change.

Temporal and spatial characterization of neuronal injury following lateral fluid-percussion brain injury in the rat

The pattern of neuronal injury following lateral fluid-percussion (FP) brain injury in the rat was systematically characterized at sequential time points to identify selectively vulnerable regions and to determine the temporal contribution of primary and delayed neuropathological events. Male Sprague-Dawley rats (n = 28) were killed 10 min, 2 h, 12 h, 24 h, 4 days, and 7 days following a lateral FP brain injury of moderate severity (2.2 atm), or 24 h after a sham injury. Brain sections were stained and analyzed using Nissl, acid fuchsin, and silver staining methods to identify regions with injured neurons or with visible lesions. Extensive numbers of acid fuchsin or silver-stained neurons were observed as early as 10 min after the FP brain injury in regions extending from the caudate/putamen to the pons. The frequency of injured neurons was greatest in the ipsilateral cortex, hippocampus, and thalamus, and a visible loss of Nissl-stained neurons was observed in these regions beginning at 12 h after the FP brain injury. Acid fuchsin-stained neurons were restricted to the same brain regions for all of the survival periods and gradually decreased in numbers between 24 h and 7 days after injury. These findings suggest that lateral FP brain injury in the rat produces a combination of focal cortical contusion and diffuse subcortical neuronal injury, which is present within minutes of the impact, progresses to a loss of neurons by 12 h, and does not markedly expand into other brain regions with survival periods up to 7 days. Furthermore, the acute onset and rapid evolution of the neuronal injury process may have important implications when considering a window of opportunity for pharmacological intervention.

Health outcome assessment before and after adult deformity surgery. A prospective study

STUDY DESIGN

Fifty-five patients undergoing surgery for adult spinal deformity assessed their health status using a generic health outcome instrument before surgery and at an average of 2 years after surgery.

OBJECTIVE

To assess whether adult spinal deformity surgery is a useful intervention when patients evaluate their own perception of health. The Medical Outcomes Survey Short Form-36, a validated generic health outcome assessment form, was used to measure patient's health status.

SUMMARY OF BACKGROUND DATA

Surgery for adult scoliosis is technically demanding. No study that we are aware of uses a generic health outcome instrument in a prospective manner to compare patients' perception of their health after adult scoliosis surgery. The Medical Outcomes Survey Short Form-36 has been validated in multiple studies assessing other medical conditions and was found to be reliable, comprehensive, brief, and generic.

METHODS

Sixty-eight adult patients undergoing surgery for adult spinal deformity were prospectively enrolled. Fifty-five patients were available to complete the Medical Outcomes Surgery Short Form-36 after surgery. The scores of the health profile were compared before and after surgery. The results of patients younger than 40 years were compared with those of patients older than 40 years. The results of patients younger than 40 years were compared with those of patients older than 40 years. The results of patients fused to more caudal end vertebral levels ((L4, L5)5) were compared with those who were fused to more cranial end vertebral levels. The results of patients without complications after surgery were compared with those of patients with complications after surgery.

RESULTS

Average follow-up period was 22.5 months (minimum 12 months) in 82% of 68 patients. Statistically significant improvements were seen in postoperative scores for physical function, social function, bodily pain, and perceived health change. We found no significant differences in self-reported health function parameters related to age ( > 40 vs. < 40), end vertebral level of fusion, or presence of complications after surgery.

CONCLUSIONS

Applying a generic health outcome instrument to adult spinal deformity surgery shows that adult scoliosis surgery significantly improves patient self-reported health assessment and function. Beneficial results do not appear to deteriorate with age or more caudal end vertebral levels of fusion. Future studies combining disease-specific outcomes analysis and generic health surveys to assess end results of adult spinal deformity surgery will be useful.

Kynurenate is neuroprotective following experimental brain injury in the rat

Pharmacologic inhibition of excitatory amino acid neurotransmission improves physiologic, metabolic, and neurobehavioral outcome following experimental brain trauma. However, no studies to date have demonstrated pharmacologically-induced attenuation of histopathological changes associated with experimental brain injury models. The present study examined the effects of kynurenate, an NMDA and non-NMDA receptor antagonist, on neuronal survival in the hippocampus after lateral fluid-percussion brain injury in the rat. Animals (n = 10/treatment) randomly received an intravenous injection of either kynurenate (300 mg/kg) or buffer (equal volume) 15 min following fluid-percussion brain injury of moderate severity. Two weeks after injury, animals were sacrificed and neuronal cell loss in the hippocampus was examined with Nissl staining. Selective loss of neurons in the CA3 region of the hippocampus, which has previously been characterized in this model of brain injury, was found to be significantly attenuated following kynurenate treatment (P < 0.05). These data suggest that pharmacologic compounds which are known to have beneficial effects on neurobehavioral and physiological outcome following brain injury may also significantly attenuate post-traumatic neuronal cell loss. Our results also support other recent data that pharmacological intervention with an excitatory amino acid receptor antagonist may be of therapeutic value in the treatment of brain injury.

Early versus late replacement of autotransfused blood in elective spinal surgery. A prospective randomized study

The use of autologous blood is a well established and extremely popular technique to decrease the necessity for homologous transfusions and the attendant risks of hepatitis, HIV, and HTLV--I/II infections. The most beneficial timing for autologous reinfusion of predonated blood remains unknown. The present study was undertaken to determine the optimal timing of autologous blood reinfusion in elective spinal surgery. Fifty-seven patients were prospectively individually randomly allocated into early versus delayed reinfusion groups prior to undergoing elective spinal surgery by a single surgeon. Three surgical subgroups were entered into the study: anterior/posterior (A/P) spinal fusion patients, posterior thoracolumbar scoliosis fusion patients (PSF), and degenerative posterior lumbar fusion patients (LF). Randomization was successful in that three was no significant difference in male to female ratio, age, preoperative hemoglobin, or number of units predonated between the early and delayed reinfusion groups. Likewise, there was no significant difference in the details of the operative procedure when compared as a group for the early versus delayed reinfusion groups. A significant increase in the postoperative day #1, 2 and 3 hemoglobin was seen in the early reinfusion group, while there was no significant difference seen in the postoperative day #7 hemoglobin between the early versus delayed reinfusion group. There was no effect of surgical grouping on these significant comparisons. Earlier patient mobilization was also seen in the early reinfusion groups for the A/P and PSF groups. There was no difference in patients' subjective evaluation of satisfaction and discomfort between the early or delayed reinfusion groups as determined by blinded interview on days 1, 3, 5, and 7 postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Vasoactive neurochemicals identified in omentum: a preliminary report

There has been increasing interest in biologic, immunologic, and chemical activity originating from omental tissue. Since clinical improvement has been observed in some patients very shortly after surgically transposing their omentum to the spinal cord or brain, the question arose as to whether neurochemicals might be present in omental tissue; a possible explanation for some of these neurological changes. This paper reports the presence of vasoactive neurochemicals in canine omental tissue. It remains unclear, however, whether the omentum produces or simply concentrates these and other neurochemicals.

Elevation of circulating beta-endorphin levels with concomitant depression of immune parameters after traumatic injury

Immunosuppression is frequently observed after traumatic injury, and is associated with the subsequent development of sepsis. Although a number of factors such as age, nutritional status, and the degree of injury have been related to the severity of the immunosuppression that occurs, the physiologic alterations leading to immunosuppression are not well defined. We hypothesized that changes in the endogenous opiate peptides, such as beta-endorphin, might contribute to changes in the immune system following injury. Levels of circulating beta-endorphin, responsiveness to the mitogen PHA, and the frequency of circulating T11, T4, and T8 cells were measured in trauma patients hospitalized in a surgical intensive care unit. beta-endorphin levels were elevated during the first 4 days after trauma (134.1 +/- 22.5 vs. 49.3 +/- 4.3 pg/ml, mean +/- S.E., patient vs. control; p less than 0.001). During the same time period patient PHA response (10,852 +/- 3,775 vs. 28,147 +/- 12,078; p less than 0.05), and the per cent of T4 positive (31.2 +/- 2.6 vs. 47.0 +/- 1.4; p less than 0.001) cells were lower than controls. These parameters were not significantly different from control values when measured at later times. Thus we conclude there is a temporal association of depressed immune parameters and elevated beta-endorphin levels after traumatic injury.

Plasma beta-endorphin levels in primary aldosteronism

Excessive production of an as yet unidentified aldosterone-stimulating factor may cause idiopathic hyperaldosteronism (IHA). This putative factor may be related to proopiomelanocortin-derived peptides, some of which have aldosterone-stimulating properties. The present study evaluated plasma beta-endorphin, ACTH, cortisol, and aldosterone levels in patients with IHA (n = 10), aldosterone-producing adenomas (n = 4), essential hypertension (n = 11), and normal subjects (n = 10). Plasma and urinary hormone measurements were obtained at timed intervals during an isocaloric, fixed electrolyte intake (Na+, 128 meq/day; K+, 80 meq/day) in a metabolic unit. Plasma for beta-endorphin assay was preincubated with sepharose-bound anti-beta-lipotropin to remove beta-lipotropin that cross-reacted with the beta-endorphin RIA. Mean +/- SE plasma beta-endorphin levels at 0800 h were elevated in IHA patients (47 +/- 13 fmol/ml) compared to those in aldosterone-producing adenoma (25 +/- 9), essential hypertension (16 +/- 1), and normal control (20 +/- 2; P less than 0.05) subjects. Plasma ACTH, plasma cortisol, and urinary cortisol levels were not different in these four groups. These data support the hypothesis that excess production of either beta-endorphin or related proopiomelanocortin-derived peptides may function as aldosterone secretogogue(s) in IHA.

Elevated plasma levels of beta-endorphin in a group of women with polycystic ovarian disease

The relationship of endogenous opiates in patients with polycystic ovarian disease (PCOD) and their influence on body weight was studied. The study group consisted of 19 women with PCOD. They were amenorrheic, hirsute, and hyperandrogenic, and their average weight was 124% of the ideal body weight. They had luteinizing hormone/follicle-stimulating hormone ratios greater than or equal to 2. The control group consisted of ten women with regular ovulatory menses. Plasma beta-endorphin (beta-EP) was measured by using a very specific radioimmunoassay. beta-Lipotropin (beta-LPH) was entirely removed from the sample by preincubation of the plasma with rabbit anti-beta-LPH/Sepharose complex (Pharmacia, New Brunswick, NJ). The mean +/- standard deviation of the plasma beta-EP in the control group was 70.18 +/- 18.06 pg/ml, and the mean +/- standard deviation of beta-EP in the study group was 185.6 +/- 93.4 pg/ml, which was significantly higher than the control levels (P less than 0.001). A significant correlation was also found between plasma beta-EP level and the patient's weight in the PCOD group (r = 0.462, P = 0.025). The data from this study suggest that the elevated levels of endogenous opiates may be involved in the pathophysiology of PCOD and be related to inappropriate secretion of gonadotropins influencing body weight.

Temporal characteristics of cortisol metabolism in adrenalectomized primates

The rhythmicities observed in the plasmatic levels of cortisol are generally attributed to rhythms of production and release of the hormone. Since the plasmatic concentration of any given substance is a function of its production and its removal from the circulation, it is conceivable that the metabolism of cortisol also occurs in an oscillating fashion. To test this hypothesis Rhesus monkeys were submitted to bilateral adrenalectomy; cortisol was replaced at a constant infusion rate while blood was sampled at hourly intervals for the measurement of cortisol plasma levels. Rhythmic oscillations in the cortisol levels were observed. These rhythms exhibited two major components: a circadian and an ultradian component. The authors suggest that these rhythms be considered whenever normal or pathologic hormone rhythmicities are analyzed.