Development of the What Matters 2 Adults (WM2A) wellbeing measure for Aboriginal and Torres Strait Islander adults

PURPOSE

As wellbeing is culturally bound, wellbeing measures for Aboriginal and Torres Strait Islander peoples must be culturally relevant and grounded in Aboriginal and Torres Strait Islander values and preferences. We describe the development of a nationally-relevant and culturally grounded wellbeing measure for Aboriginal and Torres Strait Islander adults: the What Matters to Adults (WM2A) measure.

METHODS

We used a mixed methods approach to measure development, combining Indigenist methodologies and psychometric methods. Candidate items were derived through a large national qualitative study. Think-aloud interviews (n = 17) were conducted to assess comprehension, acceptability, and wording of candidate items. Two national surveys collected data on the item pool (n = 312, n = 354). Items were analysed using exploratory factor analysis (EFA), and item response theory (IRT) to test dimensionality, local dependence and item fit. A Collaborative Yarning approach ensured Aboriginal and Torres Strait Islander voices were privileged throughout.

RESULTS

Fifty candidate items were developed, refined, and tested. Using EFA, an eight factor model was developed. All items met pre-specified thresholds for maximum endorsement frequencies, and floor and ceiling effects; no item redundancy was identified. Ten items did not meet thresholds for aggregate adjacent endorsement frequencies. During Collaborative Yarning, six items were removed based on low factor loadings (<0.4) and twelve due to conceptual overlap, high correlations with other items, endorsement frequencies, and/or low IRT item level information. Several items were retained for content validity. The final measure includes 32 items across 10 domains (Balance & control; Hope & resilience; Caring for others; Culture & Country; Spirit & identity; Feeling valued; Connection with others; Access; Racism & worries; Pride & strength).

CONCLUSIONS

The unique combination of Indigenist and psychometric methodologies to develop WM2A ensures a culturally and psychometrically robust measure, relevant across a range of settings and applications.

Chorioamnionitis disrupts erythropoietin and melatonin homeostasis through the placental-fetal-brain axis during critical developmental periods

Introduction: Novel therapeutics are emerging to mitigate damage from perinatal brain injury (PBI). Few newborns with PBI suffer from a singular etiology. Most experience cumulative insults from prenatal inflammation, genetic and epigenetic vulnerability, toxins (opioids, other drug exposures, environmental exposure), hypoxia-ischemia, and postnatal stressors such as sepsis and seizures. Accordingly, tailoring of emerging therapeutic regimens with endogenous repair or neuro-immunomodulatory agents for individuals requires a more precise understanding of ligand, receptor-, and non-receptor-mediated regulation of essential developmental hormones. Given the recent clinical focus on neurorepair for PBI, we hypothesized that there would be injury-induced changes in erythropoietin (EPO), erythropoietin receptor (EPOR), melatonin receptor (MLTR), NAD-dependent deacetylase sirtuin-1 (SIRT1) signaling, and hypoxia inducible factors (HIF1α, HIF2α). Specifically, we predicted that EPO, EPOR, MLTR1, SIRT1, HIF1α and HIF2α alterations after chorioamnionitis (CHORIO) would reflect relative changes observed in human preterm infants. Similarly, we expected unique developmental regulation after injury that would reveal potential clues to mechanisms and timing of inflammatory and oxidative injury after CHORIO that could inform future therapeutic development to treat PBI. Methods: To induce CHORIO, a laparotomy was performed on embryonic day 18 (E18) in rats with transient uterine artery occlusion plus intra-amniotic injection of lipopolysaccharide (LPS). Placentae and fetal brains were collected at 24 h. Brains were also collected on postnatal day 2 (P2), P7, and P21. EPO, EPOR, MLTR1, SIRT1, HIF1α and HIF2α levels were quantified using a clinical electrochemiluminescent biomarker platform, qPCR, and/or RNAscope. MLT levels were quantified with liquid chromatography mass spectrometry. Results: Examination of EPO, EPOR, and MLTR1 at 24 h showed that while placental levels of EPO and MLTR1 mRNA were decreased acutely after CHORIO, cerebral levels of EPO, EPOR and MLTR1 mRNA were increased compared to control. Notably, CHORIO brains at P2 were SIRT1 mRNA deficient with increased HIF1α and HIF2α despite normalized levels of EPO, EPOR and MLTR1, and in the presence of elevated serum EPO levels. Uniquely, brain levels of EPO, EPOR and MLTR1 shifted at P7 and P21, with prominent CHORIO-induced changes in mRNA expression. Reductions at P21 were concomitant with increased serum EPO levels in CHORIO rats compared to controls and variable MLT levels. Discussion: These data reveal that commensurate with robust inflammation through the maternal placental-fetal axis, CHORIO impacts EPO, MLT, SIRT1, and HIF signal transduction defined by dynamic changes in EPO, EPOR, MLTR1, SIRT1, HIF1α and HIF2α mRNA, and EPO protein. Notably, ligand-receptor mismatch, tissue compartment differential regulation, and non-receptor-mediated signaling highlight the importance, complexity and nuance of neural and immune cell development and provide essential clues to mechanisms of injury in PBI. As the placenta, immune cells, and neural cells share many common, developmentally regulated signal transduction pathways, further studies are needed to clarify the perinatal dynamics of EPO and MLT signaling and to capitalize on therapies that target endogenous neurorepair mechanisms.

Left Ventricular Pseudoaneurysm in Lemierre’s Syndrome: a case report

Background

Lemierre’s Syndrome is an infectious phenomenon characterised by oropharyngeal infection with bacteraemia, thrombophlebitis and distant septic emboli. Septic emboli are a recognised cause of a type 2 myocardial infarction, with a left ventricular pseudoaneurysm being a rare but important complication of this.

Case Summary

A 19-year-old male presented with acute confusion, fevers and a cough. Blood cultures were positive for Fusobacterium necrophorum and initial imaging showed a cavitating pneumonia. Further evaluation revealed septic emboli in the distal digits and brain. The patient initially responded to antibiotic therapy but developed chest pain and a raised troponin. An ECG showed inferolateral ST elevation. A transthoracic echocardiogram (TTE) showed hypokinesia of the mid to apical lateral wall and a computed tomography (CT) scan showed a pericardial effusion with a possible purulent effusion or abscess. The patient underwent surgical drainage of a sterile effusion. A post-operative TTE and CT demonstrated a left ventricular pseudoaneurysm which was surgically repaired. Venous thrombus was encountered intraoperatively confirming a diagnosis of Lemierre’s Syndrome. The patient completed antibiotics and had a good postoperative recovery.

Discussion

This is the first case described of left ventricular pseudoaneurysm as a complication of Lemierre’s Syndrome. It highlights not only the importance of serial, multimodality imaging in both the diagnostic workup and identification of complications, but also the importance of the multidisciplinary team in the management of patients with complex and rare presentations.

Quantitative evaluation of coronary artery occlusion by 3D coronary volume reconstruction in a large animal model of acute myocardial infarction

Background

Large animal models of acute myocardial infarction (MI) offer an important platform to test novel therapies. Consistency of infarct size between animals is critical to ensure an accurate assessment of therapies against control. However, anatomical variation challenges the ability to achieve a consistent infarct size and care must be taken to respect the principles of the 3Rs through minimisation of interventional fatalities.

Purpose

To standardise the approach of a closed chest model of balloon occlusion-facilitated MI. Novel 3-dimensional quantitative coronary angiography (3DQCA) software has been used retrospectively to identify a correlation between coronary volume occlusion and the extension of the myocardial scar.

Methods

Twenty-four Yorkshire pigs (mean weight 63.1±3 kg) underwent a closed chest MI model via percutaneous occlusion of the mid portion of the left anterior descending artery (LAD) for 60 minutes. The evaluation of the myocardial damage was obtained via cardiac magnetic resonance imaging (CMR) between 24 and 48 hours after the MI model (Acute) and at 4–5 weeks after MI (Chronic). Troponin I was also measured at multiple timepoints. 3DQCA reconstruction (QAngio XA 3D, Medis medical imaging systems NL) was generated from 2 angiographic projections with segmental analysis of all 3 major epicardial vessels including lumen volume, reference diameters, and segment length. The occlusive volume and vessel length was identified through co-registration of balloon position.

Results

At the short term timepoint, a significant correlation was found between the LAD volume occluded and the scar size as percentage of the LV mass (Spearman correlation 0.72, p value &lt;0.01, Fig. 1). Using Youden index analysis we identified a cut-off point of 32.8% of the LAD volume to determine a scar volume &gt;20% (Fig. 2). At chronic phase the correlation between these two variables was not significant, although there was a trend towards significance (p value = 0.06, Cor = 0.54). No significant correlation was found with serum Troponin I.

Conclusions

There is a significant correlation between the LAD volume occluded and the overall scar size in the acute phase and at least 32.8% of the LAD volume should be occluded to determine a scar volume &gt;20% of the entire LV. This indicates that a prospective measure of occluded LAD volume might minimise the intra-experimental variability in studies aiming to reduce infarct size and acute myocardial injury.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): This research work was supported by grants awarded to Professor Ascione: the British Heart Foundation (BHF) (BHF IG/14/2/30991, BHF RM/13/2/30158), and the Medical Research Council (MRC) (MRC MR/L012723/1).

An exploration of the sociodemographic and health conditions associated with self-rated wellbeing for Aboriginal and Torres Strait Islander adults

Objective

To identify sociodemographic factors and health conditions associated with self-rated wellbeing for Aboriginal and Torres Strait Islander adults. Participants were recruited via investigator networks and an online panel provider with an established nationwide panel of Aboriginal and Torres Strait Islander adults. Those interested were invited to complete a survey that included an assessment of wellbeing using a visual analogue scale. Data was collected from October–November 2019 and August–September 2020. Exploratory analyses were conducted to ascertain factors associated with self-rated wellbeing for Aboriginal and Torres Strait Islander adults.

Results

Having more than enough money to last until next pay day, full-time employment, completion of grade 12, having a partner, and living with others were significantly associated with higher wellbeing among Aboriginal and Torres Strait Islander adults. A self-reported history of depression, anxiety, other mental health conditions, heart disease, or disability were associated with lower self-rated wellbeing scores. Our findings indicate a need for further investigation among these socioeconomic and patient groups to identify how to improve and support the wellbeing of Aboriginal and Torres Strait Islander adults.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05794-3.

Quantitative evaluation and comparison of coronary artery characteristics by 3D coronary volume reconstruction

Non-atherosclerotic abnormalities of vessel calibre, aneurysm and ectasia, are challenging to quantify and are often overlooked in qualitative reporting. Utilising a novel 3-dimensional (3D) quantitative coronary angiography (QCA) application, we have evaluated the characteristics of normal, diabetic and aneurysmal or ectatic coronary arteries. We selected 131 individuals under 50 years-of-age, who had undergone coronary angiography for suspected myocardial ischaemia between 1st January 2011 and 31st December 2015, at the Bristol Heart Institute, Bristol, UK. This included 42 patients with angiographically normal coronary arteries, 36 diabetic patients with unobstructed coronaries, and 53 patients with abnormal coronary dilatation (aneurysm and ectasia). A total of 1105 coronary segments were analysed using QAngio XA 3D (Research Edition, Medis medical imaging systems, Leiden, The Netherlands). The combined volume of the major coronary arteries was significantly different between each group (1240 ± 476 mm³ diabetic group, 1646 ± 391 mm³ normal group, and 2072 ± 687 mm³ abnormal group). Moreover, the combined coronary artery volumes correlated with patient body surface area (r = 0.483, p < 0.01). Inter-observer variability was assessed and intraclass correlation coefficient of the total coronary artery volume demonstrated a low variability of 3D QCA (r = 0.996, p < 0.001). Dedicated 3D QCA facilitates reproducible coronary artery volume estimation and allows discrimination of normal and diseased vessels.

How relevant is the ISCHEMIA trial to a rapid access chest pain clinic cohort of patients?

Background

The ISCHEMIA trial demonstrated that optimal medical therapy (OMT) is not inferior to an early interventional approach for stable angina. This could significantly impact on clinical practice. This study aimed to check the relevance of the ISCHEMIA trial in a real-world population of patients referred to a tertiary centre with recent onset chest pain (CP).

Methods

In this registry study, electronic notes of all patients assessed in a Rapid Access Chest Pain Clinic (RACPC) within a 12-month period (2018–19) were reviewed. Patients were selected if they met key ISCHEMIA trial inclusion criteria.

Results

2416 patients were assessed, 378 (15.6%) presented with typical anginal CP, 1357 (56.2%) had atypical CP and 681 (28.2%) had non anginal CP.

Of the typical CP group, 158 patients were excluded (91 known CAD, 62 ACS, 2 eGFR &lt;30mL/min, 3 severe LVSD). This resulted in 220 patients, representing 58.2% of the typical chest pain population and 9.1% of all patients seen in RACPC. These patients had a median age of 60 years, 96 (44%) female, 119 (54.1%) had high cholesterol, 44 (20%) had diabetes, 115 (52.3%) had hypertension, 104 (47.3%) had a family history of ischaemic heart disease, and 32 (14.5%) were current smokers.

Of these 220 patients, 48 (21.8%) had a CT coronary angiogram (CTCA) requested as their first line investigation (42 completed) with 1 (2.4%) patients result suggestive of significant left main stem (LMS) disease. 15 (6.8%) patients had stress echocardiography requested as their first line investigation (13 completed), 4 (31%) were positive for inducible ischaemia. 3 (1.4%) patients had stress CMR requested as their first line investigation (2 completed), both were negative. 143 (65%) patients had an invasive coronary angiogram (ICA) requested as their first line investigation (112 completed). 8 patients had severe LMS disease and were referred for surgical opinion. A further 11 patients were referred for surgical opinion due to multivessel disease or aberrant coronary anatomy. In total 24 (21.4%) patients were treated with PCI following ICA as their first line investigation.

All patients were started on medical therapy for presumed CAD with up-titration while awaiting investigations. The median wait time for a CTCA was 55 days compared to 165.5 days for ICA.

Two patients (0.9%) from the cohort of 220 patients died during the follow up period, compared to 2.5% of patients admitted from RACPC with an ACS diagnosis.

Conclusion

Patients present with undifferentiated chest pain, consequently the outcomes of the ISCHEMIA trial must be considered cautiously. Within our cohort of 2416 patients, only 9% of patients met key inclusion criteria of the trial. Ultimately, only 19.5% patients with typical chest pain were revascularised, unlike 80% of patients in the invasive arm of ISCHEMIA. It is unclear how the results of the ISCHEMIA trial will impact on UK practice, but it is clear that OMT plays a central role.

Funding Acknowledgement

Type of funding source: None

An exploration of healthcare providers' experiences and perspectives of Traditional and complementary medicine usage and disclosure by Indigenous cancer patients

Background

Traditional and complementary medicines (T&CM) are any form of medicine, practice, treatment, product, technology, knowledge system or ceremony outside of conventional medical practice that aims to prevent and/or treat illness and/or promote well-being. Alongside conventional cancer treatments, T&CM usage is increasing; with 19% of indigenous Australians with cancer reporting using T&CM. There is limited evidence surrounding T&CM use and disclosure by indigenous patients. Our aim was to explore healthcare providers’ views about usage, disclosure/non-disclosure of T&CM by Indigenous cancer patients.

Methods

Semi-structured, in-depth interviews with 18 healthcare providers, including three indigenous providers, at a large urban hospital providing care to Indigenous cancer patients were conducted to explore providers’ experiences and attitudes towards T&CM use by Indigenous cancer patients. An interpretive phenomenological approach was used to thematically analyse the data.

Results

Analysis revealed six themes: concern about risk; no ‘real’ benefits; perception of T&CM and conventional medicine as antithetical; barriers to disclosure; ‘patients’ choice’ a double-edged sword; and providers’ lack of knowledge about T&CM. Healthcare providers perceived discord between T&CM and conventional medicine. Most lacked knowledge of T&CM, and had concerns around negative-interactions with conventional treatments. They considered T&CM outside their role, citing this as reasoning for their lack of knowledge. Indigenous healthcare providers had greater understanding and openness towards T&CM.

Conclusions

Given the potential usage of T&CM by Indigenous cancer patients, providers need a more comprehensive understanding of T&CM in order to inform discussion and facilitate effective disclosure on this topic. If indigenous Australians with cancer feel that cancer care providers are unreceptive to discussing T&CM, patient care risks being compromised; particularly given the potential for negative interactions between T&CM and conventional cancer treatments. Fostering health care interactions where indigenous patients feel comfortable to discuss T&CM usage should be a priority for all cancer care services.

Exploring traditional and complementary medicine use by Indigenous Australian women undergoing gynaecological cancer investigations

BACKGROUND

Indigenous Australian women experience worse gynaecological cancer outcomes than non-Indigenous women. While traditional and complementary medicine (T&CM) is increasingly used by cancer patients alongside conventional treatments, little is known about T&CM use by Indigenous women. This study aimed to explore the beliefs, attitudes and experiences related to T&CM use and disclosure among Indigenous women undergoing gynaecological cancer investigations.

METHODS

A mixed-methods design explored T&CM use among Indigenous women who presented for gynaecological cancer investigation at an urban Queensland hospital (September 2016 and January 2018).

RESULTS

Fourteen women participated. The reported use (86%) and perceived value of T&CM was high among the participants, however, women reported major challenges in communicating with healthcare providers about T&CM, commonly associated with trust and rapport.

CONCLUSIONS

These findings highlight the need for strategies to facilitate culturally-appropriate doctor-patient communication around T&CM to foster trust and transparency in gynaecological cancer care for Indigenous women.

Single-molecule probing of amyloid nano-ensembles using the polymer nanoarray approach

Soluble amyloid-beta (Aβ) oligomers are the prime causative agents of cognitive deficits during early stages of Alzheimer's disease (AD). The transient nature of the oligomers makes them difficult to characterize by traditional techniques, suggesting that advanced approaches are necessary. Previously developed fluorescence-based tethered approach for probing intermolecular interactions (TAPIN) and AFM-based single-molecule force spectroscopy are capable of probing dimers of Aβ peptides. In this paper, a novel polymer nanoarray approach to probe trimers and tetramers formed by the Aβ(14-23) segment of Aβ protein at the single-molecule level is applied. By using this approach combined with TAPIN and AFM force spectroscopy, the impact of pH on the assembly of these oligomers was characterized. Experimental results reveal that pH affects the oligomer assembly process. At neutral pH, trimers and tetramers assemble into structures with a similar stability, while at acidic conditions (pH 3.7), the oligomers adopt a set of structures with different lifetimes and strengths. Models for the assembly of Aβ(14-23) trimers and tetramers based on the results obtained is proposed.

[Live Animals and Staged Nature : Drawing and Photography in German Popular Zoology between 1860 and 1910]

It is the central thesis of this paper that the "biological perspective" (Lynn Nyhart) typical for Germany, with its interest in living animals, not only influenced natural history practices in many ways during the second half of the 19th century, rather also shaped the illustrations of popular zoology publications, as for example those in Brehms Thierleben. The illustrators of this period preferred to use live animals as models, which they studied in zoos. These animals were often depicted in their "natural" habitats. Since the illustrators knew only very little about these habitats, they had to be imagined. Another fashionable genre within popular zoology was the portrayal of animals fighting, which attracted attention because of their drama. The first wildlife photographers oriented themselves on the zoological illustrations and, with the aid of manipulation, staging and retouching, gave their photographs the impression of natural surroundings and drama. Yet both the illustrators and the photographers emphasized their truth to nature and - based on this - the scientific value of their pictures. In so doing, they developed a "biological" kind of wildlife photography, which, after the turn of the 19th century, allowed dedicated amateurs to create a popular zoological oeuvre that was well received by broad audiences.

A flexible nanoarray approach for the assembly and probing of molecular complexes

Immobilization is a key step involved in probing molecular interactions using single-molecule force spectroscopy methods, including atomic force microscopy (AFM). To our knowledge, we describe a novel approach termed flexible nanoarray (FNA) in which the interaction between the two internally immobilized amyloid β peptides is measured by pulling of the tether. The FNA tether was synthesized with nonnucleotide phosphoramidite monomers using the DNA synthesis chemistry. The two anchoring points for immobilization of the peptides inside the tether were incorporated at defined distances between them and from the ends of the polymer. Decamers of amyloid β peptide capable of dimer formation were selected as a test system. The formation of the peptide dimers was verified by AFM force spectroscopy by pulling the tether at the ends. In these experiments, the thiolated end of the FNA tether was covalently immobilized on the AFM substrate functionalized with maleimide. The other end of the FNA tether was functionalized with biotin to form a noncovalent link with the streptavidin functionalized AFM tip during the approach stage. The dimers' rupture fingerprint was unambiguously identified on the force curves by its position and the force value. The FNA design allowed reversible experiments in which the monomers were allowed to associate after the rupture of the dimers by performing the approach stage before the rupture of the biotin-streptavidin link. This suggests that the FNA technique is capable of analyzing multiple intermolecular interactions in the same molecular complex. The computational analysis showed that the tethered peptides assemble into the same dimer structure as that formed by nontethered peptides, suggesting that the FNA tether has the necessary flexibility to enable assembly of the dimer even during the course of the force spectroscopy experiment.

A Metal-free Click Chemistry Approach for the Assembly and Probing of Biomolecules

Probing of biomolecular complexes by single-molecule force spectroscopy (SMFS) methods including AFM requires proper and suitable coupling methods for immobilization of biomolecules onto the AFM tip and the surface. The use of flexible tethers for the coupling process has dual advantages. First, they allow the specific immobilization of interacting molecules, and second, their flexibility facilitates the proper orientation of the interacting partners. Recently, we developed an approach termed Flexible Nano Array (FNA) in which interacting partners are located on the same polymeric FNA molecule separated by a flexible segment with a defined length. In this paper, we modified the FNA tether approach by incorporating click chemistry with non-metal modification. FNA was synthesized using DNA synthesis chemistry, in which phosphoramidite (PA) spacers containing six ethylene glycol units were used instead of nucleoside triphosphates. During the synthesis, two T modifiers conjugated to two dibenzocyclooctyl (DBCO) residues were incorporated at selected positions within the FNA. The DBCO functionality allows for coupling azide labeled biomolecules via click chemistry. Amyloid peptide Aβ(14-23) terminated with azide was incorporated into the FNA and the reaction was controlled with mass-spectrometry. Assembly of tethered Aβ(14-23) peptides into dimers was characterized by AFM force spectroscopy experiments in which the AFM tip functionalized with FNA terminated with biotin probed a streptavidin-coated mica surface. The formation of the peptide dimer was verified with force spectroscopy that showed the appearance of a specific fingerprint for dimer dissociation followed by a rupture event for the biotin-streptavidin link. The developed approach is capable of multiple probing events to allow the collection of a large set of data for a quantitative analysis of the force spectroscopy events.

Assessment of three approaches for regulatory decision making on pesticides with endocrine disrupting properties

Recent EU legislation has introduced endocrine disrupting properties as a hazard-based "cut-off" criterion for the approval of active substances as pesticides and biocides. Currently, no specific science-based approach for the assessment of substances with endocrine disrupting properties has been agreed upon, although this new legislation provides interim criteria based on classification and labelling. Different proposals for decision making on potential endocrine disrupting properties in human health risk assessment have been developed by the German Federal Institute for Risk Assessment (BfR) and other regulatory bodies. All these frameworks, although differing with regard to hazard characterisation, include a toxicological assessment of adversity of the effects, the evaluation of underlying modes/mechanisms of action in animals and considerations concerning the relevance of effects to humans. Three options for regulatory decision making were tested upon 39 pesticides for their applicability and to analyze their potential impact on the regulatory status of active substances that are currently approved for use in Europe: Option 1, based purely on hazard identification (adversity, mode of action, and the plausibility that both are related); Option 2, based on hazard identification and additional elements of hazard characterisation (severity and potency); Option 3, based on the interim criteria laid down in the recent EU pesticides legislation. Additionally, the data analysed in this study were used to address the questions, which parts of the endocrine system were affected, which studies were the most sensitive and whether no observed adverse effect levels were observed for substance with ED properties. The results of this exercise represent preliminary categorisations and must not be used as a basis for definitive regulatory decisions. They demonstrate that a combination of criteria for hazard identification with additional criteria of hazard characterisation allows prioritising and differentiating between substances with regard to their regulatory concern. It is proposed to integrate these elements into a decision matrix to be used within a weight of evidence approach for the toxicological categorisation of relevant endocrine disruptors and to consider all parts of the endocrine system for regulatory decision making on endocrine disruption.

Changes in the structural and material properties of the tibia in patients with spinal cord injury

STUDY DESIGN

A cross-sectional study.

OBJECTIVES

To measure the change of structural and material properties at different sites of the tibia in spinal cord-injured patients using peripheral quantitative computerised tomography (pQCT).

SETTING

Orthopaedic research centre (UK).

METHODS

Thirty-one subjects were measured--eight with acute spinal cord injury (SCI), nine with chronic SCI and fourteen able-bodied controls. pQCT scans were performed at 2% (proximal), 34% (diaphyseal) and 96% (distal) along the tibia from the tibial plateau. Structural measures of bone were calculated, and volumetric bone mineral density (vBMD) was also measured at all three levels. Muscle cross-sectional area was measured at the diaphyseal level.

RESULTS

Structurally, there were changes in the cortical bone; in the diaphysis, the shape of the cross-section changed to offer less resistance to AP bending, and the cross-sectional area of the cortical shell decreased both proximally and distally. There were corresponding changes in vBMD in the anterior aspect of the cortical diaphysis, as well as proximal and distal trabecular bone. Changes in muscle occurred more rapidly than changes in bone.

CONCLUSION

There were clear changes of both structure and material at all three levels of the tibia in chronic SCI patients. These changes were consistent with specific adaptations to reduced local mechanical loading conditions. To assess fracture risk in SCI and also to monitor the effect of therapeutic interventions, the structure of the bone should be considered in addition to trabecular bone mineral density.

Action of 5 Hz repetitive transcranial magnetic stimulation on sensory, motor and autonomic function in human spinal cord injury

OBJECTIVE

To assess the effectiveness of physiological outcome measures in detecting functional change in the degree of impairment of spinal cord injury (SCI) following repetitive transcranial magnetic stimulation (rTMS) of the sensorimotor cortex.

METHODS

Subjects with complete or incomplete cervical (or T1) SCI received real and sham rTMS in a randomised placebo-controlled single-blinded cross-over trial. rTMS at sub-threshold intensity for upper-limb muscles was applied (5 Hz, 900 stimuli) on 5 consecutive days. Assessments made before and for 2 weeks after treatment comprised the ASIA (American Spinal Injuries Association) impairment scale (AIS), the Action Research Arm Test (ARAT), a peg-board test, electrical perceptual test (EPT), motor evoked potentials, cortical silent period, cardiovascular and sympathetic skin responses.

RESULTS

There were no significant differences in AIS outcomes between real and sham rTMS. The ARAT was increased at 1h after real rTMS compared to baseline. Active motor threshold for the most caudally innervated hand muscle was increased at 72 and 120 h compared to baseline. Persistent reductions in EPT to rTMS occurred in two individuals.

CONCLUSIONS

Changes in cortical motor threshold measures may accompany functional gains to rTMS in SCI subjects.

SIGNIFICANCE

Electrophysiological measures may provide a useful adjunct to ASIA impairment scales.

Early treatment with zoledronic acid prevents bone loss at the hip following acute spinal cord injury

Osteoporosis after spinal cord injury is common. Reductions in bone density are rapid and fracture rates are higher after injury. Early treatment with 4 mg zoledronic acid significantly reduced bone loss at the hip compared to untreated individuals in the first year. Treatment appeared safe and well tolerated.

INTRODUCTION

Bone mineral density (BMD) is lost rapidly following spinal cord injury (SCI), predominantly in the lower limbs. Bone turnover markers suggest an early increase in resorption.

METHODS

A randomised, open-label study of 14 patients with acute SCI randomised to receive 4 mg IV zoledronic acid or standard treatment. BMD was measured by dual-X-ray absorptiometry at the lumbar spine and hip (femoral neck, total and trochanter) at baseline, 3, 6 and 12 months. Bone turnover markers (serum C-terminal telopeptide and Procollagen I N-terminal peptide and urinary N-terminal telopeptide/Cr ratio) were also measured.

RESULTS

After 12 months, there was a significant difference in BMD between the groups at the total hip (12.4%, p = 0.005), trochanter (13.4%, p = 0.028) and lumbar spine (2.7%, p = 0.033). However, the difference between groups at the femoral neck was not significant (4.8%, p = 0.741). In the treated group, bone resorption was reduced and remained reduced up to 12 months. Other than flu-like symptoms immediately after the infusion, no adverse events were observed.

CONCLUSION

IV zoledronic acid is an effective and well-tolerated treatment to prevent bone mineral density loss at the total hip and trochanter for up to 12 months following SCI.

Persistence of rabbit haemorrhagic disease virus genome in vaccinated rabbits after experimental infection

Rabbit haemorrhagic disease (RHD) is usually a fatal disease in rabbits which has spread rapidly across the continents. While previous studies suggested persistence in rabbits to be an important factor in the epidemiology, the relevance of field virus infection of immune rabbits has not been investigated in experimentally infected animals before. This report describes for the first time the persistence of rabbit haemorrhagic disease virus (RHDV) genome for at least 15 weeks in rabbits immunized with an inactivated vaccine as well as a subunit vaccine and subsequently challenged with virulent RHDV. The viral RNA loads were determined by real-time reverse transcription-polymerase chain reaction. No conspicuous association of the detectable amount of RHDV RNA with the type of vaccine, the time after infection and--with one exception--the level of RHDV-specific antibodies in the immunized animals was observed. The results presented in this study are an urgent evidence for the existence of carrier animals as an important factor in the epidemiology of RHD.

Solvation effect of bacteriochlorophyll excitons in light-harvesting complex LH2

We have characterized the influence of the protein environment on the spectral properties of the bacteriochlorophyll (Bchl) molecules of the peripheral light-harvesting (or LH2) complex from Rhodobacter sphaeroides. The spectral density functions of the pigments responsible for the 800 and 850 nm electronic transitions were determined from the temperature dependence of the Bchl absorption spectra in different environments (detergent micelles and native membranes). The spectral density function is virtually independent of the hydrophobic support that the protein experiences. The reorganization energy for the B850 Bchls is 220 cm(-1), which is almost twice that of the B800 Bchls, and its Huang-Rhys factor reaches 8.4. Around the transition point temperature, and at higher temperatures, both the static spectral inhomogeneity and the resonance interactions become temperature-dependent. The inhomogeneous distribution function of the transitions exhibits less temperature dependence when LH2 is embedded in membranes, suggesting that the lipid phase protects the protein. However, the temperature dependence of the fluorescence spectra of LH2 cannot be fitted using the same parameters determined from the analysis of the absorption spectra. Correct fitting requires the lowest exciton states to be additionally shifted to the red, suggesting the reorganization of the exciton spectrum.

Persistence of viral RNA in rabbits which overcome an experimental RHDV infection detected by a highly sensitive multiplex real-time RT-PCR

An internally controlled multiplex real-time RT-PCR using TaqMan probes and external standards for absolute RNA quantification was developed as a new diagnostic tool for the detection of rabbit haemorrhagic disease virus (RHDV). The test revealed a specificity of 100%, an analytical sensitivity of 10 copies/well and a linearity over a range from 10(1) to 10(10) copies. The viral loads in organs, leukocytes, sera and excretions of seropositive, convalescent rabbits which were overcoming an experimental infection with RHDV were determined using the validated assay. As a result, viral RNA was demonstrated and quantified for at least 15 weeks. Thus, a persistence of viral RNA after experimental infection of rabbits could be shown for the first time. In contrast, neither antigen nor infectious virus could be detected by antigen-ELISA, immunohistochemistry or experimental transmission. Therefore, further experiments are necessary to prove that the persistence of RNA is linked with the persistence of infectious virus particles.

Temperature broadening of LH2 absorption in glycerol solution

In order to determine the relationship between the pigment-protein and the pigment-pigment interactions, the measurements of absorption spectra of the peripheral light-harvesting complex LH2 from the purple bacteria Rhodobacter sphaeroides solvated in glycerol/buffer solution were carried out in a wide temperature range, from 4 to 250 K. The SDFs used for simulating the temperature dependence of B800 and B850 bands were determined in a parametric form. To fit experimental spectra the overall exciton-phonon coupling had to be assumed to be weak for B850 (lambda/2V approximately 0.3, where lambda is the reorganization energy and V is the nearest-neighbor dipole-dipole coupling for bacteriochlorophylls). At physiological temperatures the intermediate nuclear bath dynamics compares with the magnitude of energy gap fluctuations. Slower dynamics with kappa approximately 0.39, where kappa is the ratio of the nuclear relaxation rate and the line width parameter, determines the spectral shape of B850 whilst faster modulations characterize B800 (kappa approximately 2.39). The static disorder for the B800 band is relatively high with the characteristic value of the inhomogeneous bandwidth Gamma(inh) approximately 120 cm-1, while for the B850 band this value is almost equal to the dipole-dipole coupling strength (Gamma(inh) approximately 360 cm-1). It has been found that the LH2 absorption spectrum is likely to be influenced by the temperature dependence of the dielectric constant of the solution in the high temperature range, when the glycerol/buffer solution is in the liquid state.

KP-1212/1461, a nucleoside designed for the treatment of HIV by viral mutagenesis

We report the activities of a novel nucleoside analog against HIV. This nucleoside (KP-1212) is not a chain terminator but exerts its antiviral effects via mutagenesis of the viral genome. Serial passaging of HIV in the presence of KP-1212 causes an increase in the mutation rate of the virus leading to viral ablation. HIV strains resistant to KP-1212 have not yet been isolated. Quite to the contrary, virus treated with KP-1212 exhibited an increased sensitivity not only to KP-1212 but also to another nucleoside reverse transcriptase inhibitor (NRTI), zidovudine. HIV strains resistant to other NRTIs (e.g. zidovudine, lamivudine, stavudine, abacavir, etc.) exhibited no cross-resistance towards KP-1212. Multiple assays confirmed that KP-1212 has a favorable (low) genotoxicity profile when compared to some approved antiviral nucleosides. In addition, KP-1212 is not toxic to mitochondria nor does it exhibit any inhibitory effects on mitochondrial DNA synthesis.

Post stroke depression

Depression following stroke is common. Although it is highlighted as an issue in stroke guidelines, guidance on diagnosis or management is not given. This paper presents the original research from a literature review of Medline and the Cochrane Database on stroke and depression, and discusses some of the clinical implications of the findings.

Effect of high pressure on the photochemical reaction center from Rhodobacter sphaeroides R26.1

High-pressure studies on the photochemical reaction center from the photosynthetic bacterium Rhodobacter sphaeroides, strain R26.1, shows that, up to 0.6 GPa, this carotenoid-less membrane protein does not loose its three-dimensional structure at room temperature. However, as evidenced by Fourier-transform preresonance Raman and electronic absorption spectra, between the atmospheric pressure and 0.2 GPa, the structure of the bacterial reaction center experiences a number of local reorganizations in the binding site of the primary electron donor. Above that value, the apparent compressibility of this membrane protein is inhomogeneous, being most noticeable in proximity to the bacteriopheophytin molecules. In this elevated pressure range, no more structural reorganization of the primary electron donor binding site can be observed. However, its electronic structure becomes dramatically perturbed, and the oscillator strength of its Q(y) electronic transition drops by nearly one order of magnitude. This effect is likely due to very small, pressure-induced changes in its dimeric structure.

Probing the binding sites of exchanged chlorophyll a in LH2 by Raman and site-selection fluorescence spectroscopies

In this work we have selectively released the 800 nm absorbing bacteriochlorophyll a molecules of the LH2 protein from the photosynthetic bacterium Rhodopseudomonas acidophila, strain 10050, and replaced them with chlorophyll a (Chla). A combination of low-temperature electronic absorption, resonance Raman and site-selection fluorescence spectroscopies revealed that the Chla pigments are indeed bound in the B800 binding site; this is the first work that formally proves that such non-native chlorins can be inserted correctly into LH2.

Certain species of the Proteobacteria possess unusual bacteriochlorophyll a environments in their light-harvesting proteins

In this work, we have examined, using Fourier-transform Raman (FT-R) spectroscopy, the bacteriochlorophyll a (BChl a) binding sites in light-harvesting (LH) antennae from different species of the Proteobacteria that exhibit unusal absorption properties. While the LH1 complexes from Erythromicrobium (E.) ramosum (RC-B871) and Rhodospirillum centenum (B875) present classic FT-R spectra in the carbonyl high-frequency region, we show that in the blue-shifted LH1 complex, absorbing at 856 nm, from Roseococcus thiosulfatophilus, as well as in the B798-832 LH2 from E. ramosum, or in the B830 complex from the obligate phototrophic bacterium Chromatium purpuratum, some H-bonds between the acetyl carbonyl of the BChl a and the surrounding protein are missing. The molecular mechanisms responsible for the unusual absorption of these complexes are thus similar to those responsible for tuning of the absorption of the LH2 complexes between 850 and 820 nm. Furthermore, our results suggest that the binding pocket of the monomeric BChl in the LH2 from E. ramosum is different from that of Rps. acidphila or Rb. sphaeroides. The FT-R spectra of Chromatium purpuratum indicate that, in contrast with every LH2 complex previously studied by FT-R spectroscopy, no free-from-interaction keto groupings exist in this complex.

Conformation of bacteriochlorophyll molecules in photosynthetic proteins from purple bacteria

Fourier transform near-infrared resonance Raman spectroscopy can be used to obtain information on the bacteriochlorophyll a (BChl a) molecules responsible for the redmost absorption band in photosynthetic complexes from purple bacteria. This technique is able to distinguish distortions of the bacteriochlorin macrocycle as small as 0.02 A, and a systematic analysis of those vibrational modes sensitive to BChl a macrocycle conformational changes was recently published [Näveke et al. (1997) J. Raman Spectrosc. 28, 599-604]. The conformation of the two BChl a molecules constituting the primary electron donor in bacterial reaction centers, and of the 850 and 880 nm-absorbing BChl a molecules in the light-harvesting LH2 and LH1 proteins, has been investigated using this technique. From this study it can be concluded that both BChl a molecules of the primary electron donor in the photochemical reaction center are in a conformation close to the relaxed conformation observed for pentacoordinate BChl a in diethyl ether. In contrast, the BChl a molecules responsible for the long-wavelength absorption transition in both LH1 and LH2 antenna complexes are considerably distorted, and furthermore there are noticeable differences between the conformations of the BChl molecules bound to the alpha- and beta-apoproteins. The molecular conformations of the pigments are very similar in all the antenna complexes investigated.

Bacteriochlorin-protein interactions in native B800-B850, B800 deficient and B800-Bchla(p)-reconstituted complexes from Rhodopseudomonas acidophila, strain 10050

Recently, a method which allows the selective release and removal of the 800 nm absorbing bacteriochlorophyll a (B800) molecules from the LH2 complex of Rhodopseudomonas acidophila strain 10050 has been described [Fraser, N.J. (1999) Ph.D. Thesis, University of Glasgow, UK]. This procedure also allows the reconstitution of empty binding sites with the native pigment Bchla(p), esterified with phytol. We have investigated the bacteriochlorophylla-protein interactions in native, B800 deficient (or B850) and in B8110-bacteriochlorophylla(p)-reconstituted LH2 complexes by resonance Raman spectroscopy. We present the first direct structural evidence which shows that the reconstituted pigments are correctly bound within their binding pockets.

Characterization of the different peripheral light-harvesting complexes from high- and low-light grown cells from Rhodopseudomonas palustris

In this paper we demonstrate that the spectroscopically different peripheral light-harvesting complexes from Rhodopseudomonas palustris, strain 2.6.1, isolated from high- and low-light grown cells have widely differing bacteriochlorophyll a (BChl a) resonance Raman spectra in the high-frequency carbonyl region (1550-1750 cm-1). Complexes synthesized in low-light grown cells exhibit Raman spectra characteristic of B800-850 and B800-820 complexes, depending on the excitation conditions. The in vivo strategy for low-light adaptation in this bacterium is thus somewhat different from that generally encountered in the Rhodospirillaceae. In these bacteria, as typified by Rps. acidophila and Rps. cryptolactis, low-light conditions induce the synthesis of B800-820 only complexes in which the hydrogen bonds between the acetyl carbonyl and the B850 binding pocket are broken, inducing changes in the absorption properties of the monomeric bacteriochlorophylls. In the case of Rps. palustris, additional spectral effects occur due to the coupling of the electronic levels of the differently interacting dimers. The extensive use of differential alpha/beta-polypeptide expression [Tadros et al. (1993) Eur. J. Biochem. 217, 867-875] thus allows Rps. palustris to alter its BChl a binding site environments causing the observed spread of BChl a Qy transitions, ranging from 801 to 856 nm.

The effect of pressure on the bacteriochlorophyll a binding sites of the core antenna complex from Rhodospirillum rubrum

In this paper we examine the effect of pressure on the absorption spectrum and binding site of the core antenna complex from the photosynthetic bacterium Rhodospirillum rubrum. Absorption spectra and Raman spectra in preresonance with the Qy transition of the bacteriochlorophyll a were studied at pressures up to 625 MPa. In agreement with previous work we observe a pressure-induced red shift and broadening of the absorption spectrum. We show that at these pressures the pigments within the protein matrix at room temperature experience little if any distortion, and the hydrogen-bonding network involving the C2 and C9 carbonyl groups of the pigment molecules are undisturbed. Having shown the lack of sensitivity to pressure of the binding site interactions, which are known to modulate the absorption spectrum, we feel that it is relatively safe to attribute the pressure-induced red shift broadly to solvatochromic effects and, in particular, to the modulation of the pigment-pigment interactions by the pressure. This paper represents the first vibrational study of photosynthetic complexes at high pressure and the first application of FT Raman spectroscopy to biological molecules at high pressure.

Highly efficient and versatile synthesis of libraries of constrained beta-strand mimetics

The general approach of using a bicyclic template to produce inhibitors of the protease superfamily of enzymes has been investigated. The Diels Alder cycloaddition reaction on solid support has been found to be highly efficient for the synthesis of libraries of compounds that mimic the beta-strand secondary structure of proteins. Several potent and selective inhibitors of proteases have been discovered.

Synthesis and reactivity of aryl nitrogen mustard-oligodeoxyribonucleotide conjugates

A versatile method is described for preparing aryl nitrogen mustard-oligodeoxyribonucleotide (mustard-ODN) conjugates under anhydrous conditions. The chemistry uses DMSO soluble triethylammonium or tributylammonium salts of the ODNs. A G/A motif triplex forming ODN was chosen for study since it had been shown earlier to bind with high affinity and specificity to a duplex DNA target. A 5'-hexylamine derivative of this ODN was reacted with three different 2,3,5,6-tetrafluorophenyl ester derivatives of aryl nitrogen mustards which were designed to have different alkylation rates. An HPLC assay was used to determine reaction rates of these mustard-ODNs under various conditions. The reactivity of the mustard groups depended on chloride concentration and the presence of nucleophiles. Conjugation of mustards to G/A-containing ODNs decreased their aqueous stability. Hydrolysis and alkylation rates of these agents were consistent with reaction via an aziridinium intermediate. Rates of sequence specific alkylation within a triplex were determined by denaturing gel electrophoresis and shown to depend on inherent reactivity of the mustard group. The improved synthesis and chemical characterization of mustard-ODNs should facilitate their use as sequence specific alkylating agents and as probes for nucleic acid structure.

Influence of the protein binding site on the absorption properties of the monomeric bacteriochlorophyll in Rhodobacter sphaeroides LH2 complex

Resonance Raman spectroscopy was performed on peripheral light-harvesting proteins from Rhodobacter sphaeroides in which the residue betaArg-10 has been modified by site-selected mutagenesis. We show that this residue is indeed involved (as proposed by X-ray crystallographic studies on the LH2 complex from Rhodopseudomonas acidophila), in an H-bond with the acetyl carbonyl of the 800 nm-absorbing BChl in these proteins (B800), and that the presence of such an H-bond induces a ca. 10 nm red shift of the lowest energy transition (Qy) of this molecule. Moreover, other parameters involved in the fine tuning of the absorption of the B800 molecules may be determined from our experiments, and we propose that the local electromagnetic properties of the B800 binding site may induce an additional 10 nm red shift of this transition. These results constitute the first experimental evidence for the parameters able to modify in vivo the absorption of "monomeric" BChl molecules, i.e. BChl not involved in strong excitonic interactions, and will be of great help for understanding the absorption properties of such pigments in other light-harvesting systems.

Decreased sensitivity of human platelets to PGI2 during long-term intraarterial prostacyclin infusion in patients with peripheral vascular disease--a rebound phenomenon?

During successful treatment of peripheral vascular disease with synthetic prostacyclin no alteration in platelet function was reported (1). In 8 patients infused with synthetic prostacyclin continuously for 7 days intraarterially, the platelet function was monitored. Special attention was drawn to the platelet sensitivity in vitro for PGI2, which is discussed as an important factor maintaining the hemostatic balance. In all the patients with peripheral vascular disease between 24 and 48 hours after the beginning of the infusion a sudden decrease in platelet sensitivity accompanied by an increase in platelet count could be seen. These dramatic alterations representing probably a rebound phenomenon occurring during long-term PGI2-treatment might be an explanation for a non-beneficial effect of the treatment and in some cases a limiting factor for the continuation of the infusion itself. It is not clear, if this rebound phenomenon is due to a stimulation of an endogenous inhibitor, lowering the synthesis of a naturally occurring substance acting against this inhibitor or tachyphylaxia.