Pandemic lockdowns: who feels coerced and why? - a study on perceived coercion, perceived pressures and procedural justice during the UK COVID-19 lockdowns

BACKGROUND

This study examined perceptions of coercion, pressures and procedural injustice and how such perceptions influenced psychological well-being in those who experienced a UK COVID-19 lockdown, with a view to preparing for the possibility of future lockdowns.

METHODS

40 individuals categorised as perceiving the lockdown(s) as either highly or lowly coercive took part in one of six asynchronous virtual focus groups (AVFGs).

RESULTS

Using thematic analysis, the following key themes were identified in participants' discussions: (1) Choice, control and freedom; (2) threats; (3) fairness; (4) circumstantial factors; and (5) psychological factors.

CONCLUSIONS

As the first qualitative study to investigate the psychological construct of perceived coercion in relation to COVID-19 lockdowns, its findings suggest that the extent to which individuals perceived pandemic-related lockdowns as coercive may have been linked to their acceptance of restrictions. Preparing for future pandemics should include consideration of perceptions of coercion and efforts to combat this, particularly in relation to differences in equity, in addition to clarity of public health messaging and public engagement.

SARS-CoV and SARS-CoV-2 display limited neuronal infection and lack the ability to transmit within synaptically connected axons in stem cell-derived human neurons

Sarbecoviruses such as SARS and SARS-CoV-2 have been responsible for two major outbreaks in humans, the latter resulting in a global pandemic. While sarbecoviruses primarily cause an acute respiratory infection, they have been shown to infect the nervous system. However, mechanisms of sarbecovirus neuroinvasion and neuropathogenesis remain unclear. In this study, we examined the infectivity and trans-synaptic transmission potential of the sarbecoviruses SARS and SARS-CoV-2 in human stem cell-derived neural model systems. We demonstrated limited ability of sarbecoviruses to infect and replicate in human stem cell-derived neurons. Furthermore, we demonstrated an inability of sarbecoviruses to transmit between synaptically connected human stem cell-derived neurons. Finally, we determined an absence of SARS-CoV-2 infection in olfactory neurons in experimentally infected ferrets. Collectively, this study indicates that sarbecoviruses exhibit low potential to infect human stem cell-derived neurons, lack an ability to infect ferret olfactory neurons, and lack an inbuilt molecular mechanism to utilise retrograde axonal trafficking and trans-synaptic transmission to spread within the human nervous system.

Recently Emerged Novel Henipa-like Viruses: Shining a Spotlight on the Shrew

Henipaviruses are zoonotic viruses, including some highly pathogenic and capable of serious disease and high fatality rates in both animals and humans. Hendra virus and Nipah virus are the most notable henipaviruses, resulting in significant outbreaks across South Asia, South-East Asia, and Australia. Pteropid fruit bats have been identified as key zoonotic reservoirs; however, the increased discovery of henipaviruses outside the geographic distribution of Pteropid fruit bats and the detection of novel henipa-like viruses in other species such as the shrew, rat, and opossum suggest that Pteropid bats are not the sole reservoir for henipaviruses. In this review, we provide an update on henipavirus spillover events and describe the recent detection of novel unclassified henipaviruses, with a strong focus on the shrew and its emerging role as a key host of henipaviruses.

Henipavirus-induced neuropathogenesis in mice

Hendra virus (HeV) and Nipah virus (NiV) are henipaviruses that can cause fatal encephalitis in humans. Many animal models have been used to study henipavirus pathogenesis. In the mouse, HeV infection has previously shown that intranasal challenge can lead to neurological infection, however mice similarly challenged with NiV show no evidence of virus infecting the brain. We generated recombinant HeV (rHeV) and NiV (rNiV) where selected proteins were switched to examine their role in neuroinvasion in the mouse. These viruses displayed similar growth kinetics when compared to wildtype in vitro. In the mouse, infection outcomes with recombinant virus did not differ to infection outcomes of wildtype viruses. Virus was detected in the brain of 5/30 rHeV-challenged mice, but not rNiV-challenged mice. To confirm the permissiveness of mouse neurons to these viruses, primary mouse neurons were successfully infected in vitro, suggesting that other pathobiological factors contribute to the differences in disease outcomes in mice.

Evaluation of henipavirus chemical inactivation methods for the safe removal of samples from the high-containment PC4 laboratory

Henipaviruses, Hendra (HeV) and Nipah (NiV), are highly pathogenic zoonotic agents that pose a serious health risk to human life, and as such are restricted to physical containment 4 (PC4) laboratories. For further analysis of virus-infected biological specimens, it is necessary to ensure absolute inactivation of any infectious virus present before removal from the PC4 laboratory. To evaluate the inactivation of HeV and NiV within infected samples, two chemical inactivation methods were assessed. Henipavirus-infected cell monolayers treated with 4 % paraformaldehyde (PFA) showed the complete inactivation of infectious virus, with an inactivation period of 15 min resulting in more than 8-log decrease in infectious titre. NiV-infected tissue samples treated with 10 % neutral-buffered formalin (NBF) showed a complete reduction of infectious virus in 7/8 ferret organs incubated for 24 h, with the remaining tissue demonstrating complete virus inactivation after 48 h. The chemical inactivation methods described herein evaluated two simple methods of henipavirus inactivation, resulting in the complete inactivation of infectious virus - an essential requirement for the safe removal and handling of biological samples from the PC4 laboratory.

Factor VIII Procoagulant Protein Interacts with Phospholipid Vesicles Via its 80 kDa Light Chain

In a previous report, we detailed the fractionation of polyclonal human anti-Factor VIII :C into a component directed exclusively against the phospholipid-binding site on Factor VIII (PL-site antibody) and another directed at other sites (non-PL-site antibody). The location on the F.VIII molecule of its PL-binding site has now been studied by two different methods using this fractionated 125I-labelled anti-F.VIII: C Fab’.

The first method was modified from that of Weinstein et al. (Proc Natl Acad Sci USA 1981; 78: 5137-41), involving electrophoresis of F.VIII peptide-125I-Fab‘ A/F.VIII immunocomplexes in SDS-polyacrylamide gels. PL-site antibody reacted with F.VIII peptides of apparent Mr approximately 80 kDa and sometimes 160 kDa in plasma and concentrate, but not with larger peptides. Non-PL-site antibody, however, reacted with a range of peptides of apparent Mr 90 kDa to 280 kDa. In addition, when purified F.VIII containing heavy and light chains (HC + LC), and isolated LC peptides were analysed, PL-site antibody bound to LC peptides whereas non-PL-site antibody did not.

The second method used the antibody pools in immunoradiometric assays (IRMA’s) of purified F.VIII peptides. Both labels measured similar amounts of F.VIII: Ag in a sample of purified F.VIII containing both HC and LC; on assaying an HC preparation, however, PL-site label measured only 2% of F.VIII: Ag found by non-PL-site label, indicating that PL-binding sites are absent in HC preparations.

These results indicate that F.VIII binds to PL via its 80 kDa light chain.

Diagnostic accuracy of reflectance confocal microscopy using VivaScope for detecting and monitoring skin lesions: a systematic review

BACKGROUND

Skin cancer is one of the most common cancers in the UK. Patients with suspicious skin lesions are assessed clinically with/without dermoscopy, and lesions still considered suspicious are then surgically removed or have the diagnosis confirmed by a punch biopsy.

AIM

To evaluate the diagnostic accuracy of the in vivo VivaScope^© reflective confocal microscopy (RCM) system, a noninvasive technology designed to provide a more accurate presurgical diagnosis, leading to fewer biopsies of benign lesions, or to provide greater accuracy for lesion margins.

METHODS

MEDLINE, EMBASE and the Cochrane Library were searched to identify studies evaluating dermoscopy plus RCM, or RCM alone, with histopathology as the reference test. Clinical experts were also contacted for information on unpublished studies.

RESULTS

Eleven studies met the inclusion criteria but were too heterogeneous to be combined by meta-analysis. Results indicated that VivaScope subsequent to dermoscopy may improve diagnostic accuracy of malignant melanomas compared with dermoscopy. For margin delineation, the data suggest that mapping using VivaScope 1500 for lentigo maligna (LM) and LM melanoma may improve accuracy in terms of complete excision of lesions compared with dermoscopically determined margins. For basal cell carcinoma, the limited data show high diagnostic accuracy with both VivaScope 1500 and VivaScope 3000. Evidence on the effectiveness of VivaScope in diagnosing cutaneous squamous cell carcinomas was very limited.

CONCLUSION

The use of VivaScope 1500 following dermoscopy may improve patient care and management of suspicious skin lesions, although the generalizability of these results to the UK population remains unclear.

Extreme ultraviolet imaging of three-dimensional magnetic reconnection in a solar eruption

Magnetic reconnection, a change of magnetic field connectivity, is a fundamental physical process in which magnetic energy is released explosively, and it is responsible for various eruptive phenomena in the universe. However, this process is difficult to observe directly. Here, the magnetic topology associated with a solar reconnection event is studied in three dimensions using the combined perspectives of two spacecraft. The sequence of extreme ultraviolet images clearly shows that two groups of oppositely directed and non-coplanar magnetic loops gradually approach each other, forming a separator or quasi-separator and then reconnecting. The plasma near the reconnection site is subsequently heated from ∼1 to ≥5 MK. Shortly afterwards, warm flare loops (∼3 MK) appear underneath the hot plasma. Other observational signatures of reconnection, including plasma inflows and downflows, are unambiguously revealed and quantitatively measured. These observations provide direct evidence of magnetic reconnection in a three-dimensional configuration and reveal its origin.

Magnetic reconnection is a fundamental energy release process taking place in various astrophysical environments, but it is difficult to observe it directly. Here, the authors provide evidence of three-dimensional magnetic reconnection in a solar eruption using combined perspectives of two spacecraft.

Is magnetic topology important for heating the solar atmosphere?

Magnetic fields permeate the entire solar atmosphere weaving an extremely complex pattern on both local and global scales. In order to understand the nature of this tangled web of magnetic fields, its magnetic skeleton, which forms the boundaries between topologically distinct flux domains, may be determined. The magnetic skeleton consists of null points, separatrix surfaces, spines and separators. The skeleton is often used to clearly visualize key elements of the magnetic configuration, but parts of the skeleton are also locations where currents and waves may collect and dissipate. In this review, the nature of the magnetic skeleton on both global and local scales, over solar cycle time scales, is explained. The behaviour of wave pulses in the vicinity of both nulls and separators is discussed and so too is the formation of current layers and reconnection at the same features. Each of these processes leads to heating of the solar atmosphere, but collectively do they provide enough heat, spread over a wide enough area, to explain the energy losses throughout the solar atmosphere? Here, we consider this question for the three different solar regions: active regions, open-field regions and the quiet Sun. We find that the heating of active regions and open-field regions is highly unlikely to be due to reconnection or wave dissipation at topological features, but it is possible that these may play a role in the heating of the quiet Sun. In active regions, the absence of a complex topology may play an important role in allowing large energies to build up and then, subsequently, be explosively released in the form of a solar flare. Additionally, knowledge of the intricate boundaries of open-field regions (which the magnetic skeleton provides) could be very important in determining the main acceleration mechanism(s) of the solar wind.

Lithium or an atypical antipsychotic drug in the management of treatment-resistant depression: a systematic review and economic evaluation

BACKGROUND

Patients with treatment-resistant depression (TRD) are those with major depressive disorder that has not responded adequately to treatment. The causes of depression are not fully understood, although there is evidence to suggest that depression is a complex interaction among biological, genetic, psychosocial and environmental factors. Strategies available for the treatment of patients with TRD include pharmacological, non-pharmacological, and psychological and psychosocial interventions. Pharmacological treatment options include switching to a different antidepressant, the addition of another antidepressant of a different class, or use of an augmenting agent, such as anticonvulsants, lithium or atypical antipsychotics (AAPs). However, there is limited evidence available on the effectiveness of these strategies in the treatment of TRD.

OBJECTIVES

To estimate the clinical effectiveness and cost-effectiveness of augmentation of selective serotonin reuptake inhibitor (SSRI) antidepressant therapy with either lithium or an AAP drug in the management of people with treatment-resistant unipolar depression, defined as failure to respond to two or more antidepressant drugs in their current episode of depression.

DATA SOURCES

Databases searched were Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, MEDLINE, PsycINFO and NHS Economic Evaluation Database (NHS EED). All databases were searched from inception to August 2011. Additional data were obtained from manufacturers.

REVIEW METHODS

Systematic reviews of studies evaluating clinical effectiveness, economic analyses and quality of life (QoL) were executed. Quality assessment according to predefined criteria was undertaken independently by two reviewers. Pairwise meta-analyses and mixed-treatment comparisons (MTCs) using both fixed- and random-effects models were undertaken based on intention-to-treat analyses. A probabilistic de novo mathematical model was developed to synthesise the available data on costs and clinical outcomes from the UK NHS perspective over a 1-year time horizon (8 weeks of acute treatment captured by a decision tree and 10 months of maintenance treatment captured by a Markov model).

RESULTS

Twelve randomised controlled trials (RCTs) were identified in the review of clinical effectiveness literature; 10 considered SSRI  +  AAP compared with SSRI  +  placebo/no treatment, one considered SSRI  +  AAP compared with SSRI  +  lithium and one considered SSRI  +  lithium compared with SSRI  +  placebo. The RCTs included in the primary analyses used fluoxetine as the background SSRI and olanzapine as the AAP. Results of the MTC showed a non-significant trend in favour of lithium augmentation for response [lithium a priori odds ratio (OR) 1.29; 95% credible interval (CrI) 0.11 to 5.32; lithium post hoc OR 4.15; 95% CrI 0.25 to 20.34 (the trial informing the comparison with lithium reported response using two different definitions)], mean change in Montgomery-Åsberg Depression Rating Scale score from baseline (mean difference -  1.47, 95% CrI -  9.10 to 6.41) and all-cause withdrawals (OR 0.74, 95% CrI 0.10 to 2.66). Four economic evaluations (none directly addressing the review question) and 17 studies that reported on QoL were identified and summarised in narrative reviews. The results of the de novo modelling indicate that augmentation of SSRI with lithium dominates augmentation of an SSRI with AAP (i.e. it resulted in cost savings of £905 per person per year and generated more health benefits, estimated to be 0.03 quality-adjusted life-years). However, sensitivity analyses showed that the model was highly sensitive to changes in acute treatment efficacy (response and remission) or discontinuation. The model was not sensitive to changes in other parameters.

LIMITATIONS

In patients with TRD, there is a lack of direct evidence comparing the clinical effectiveness of augmenting an SSRI with an AAP compared with augmenting with lithium. RCTs were identified which facilitated comparison of adding AAP with adding lithium via a MTC. However, variations in the definitions of response implemented in the RCTs, together with differences in patient baseline characteristics across RCTs, introduce bias into the analysis. The direction and extent of the bias is uncertain.

CONCLUSIONS

Augmentation of SSRIs with lithium or AAP is likely to be beneficial in people with TRD. Clinical evaluation based on the limited evidence identified in this research indicates no statistically significant difference between the two augmentation strategies. Cost-effectiveness analyses suggest that augmentation with lithium is less expensive and more effective than augmentation with AAP. However, the uncertainty in the clinical estimates of discontinuation and treatment response is reflected in the model results. A RCT comparing the two augmentation strategies, reporting relevant outcomes, including QoL, is needed.

STUDY REGISTRATION

PROSPERO CRD42011001464.

Automated structure refinement for a protein heterodimer complex using limited EPR spectroscopic data and a rigid-body docking algorithm: a three-dimensional model for an ankyrin-CDB3 complex

We report here specialized functions incorporated recently in the rigid-body docking software toolkit TagDock to utilize electron paramagnetic resonance derived (EPR-derived) interresidue distance measurements and spin-label accessibility data. The TagDock package extensions include a custom methanethiosulfonate spin label rotamer library to enable explicit, all-atom spin-label side-chain modeling and scripts to evaluate spin-label surface accessibility. These software enhancements enable us to better utilize the biophysical data routinely available from various spin-labeling experiments. To illustrate the power and utility of these tools, we report the refinement of an ankyrin:CDB3 complex model that exhibits much improved agreement with the EPR distance measurements, compared to model structures published previously.

Effects of activated carbon on reductive dechlorination of PCBs by organohalide respiring bacteria indigenous to sediments

Polychlorinated biphenyls (PCBs) have accumulated in aquatic sediments due to their inherent chemical stability and their presence poses a risk due to their potential toxicity in humans and animals. Granular activated carbon (GAC) has been applied to PCB contaminated sediment sites to reduce the aqueous concentration by sequestration thus reducing the PCB exposure and toxicity to both benthic and aquatic organisms. However, it is not known how the reduction of PCB bioavailability by adsorption to GAC affects bacterial transformation of PCBs by indigenous organohalide respiring bacteria. In this study, the impact of GAC on anaerobic dechlorination by putative organohalide respiring bacteria indigenous to sediment from Baltimore Harbor was examined. It was shown that the average Cl/biphenyl after dehalogenation of Aroclor 1260 was similar between treatments with and without GAC amendment. However, GAC caused a substantial shift in the congener distribution whereby a smaller fraction of highly chlorinated congeners was more extensively dechlorinated to mono- through tri-chlorinated congeners compared to the formation of tri- through penta-chlorinated congeners in unamended sediment. The results combined with comparative sequence analysis of 16S rRNA gene sequences suggest that GAC caused a community shift to putative organohalide respiring phylotypes that coincided with more extensive dechlorination of ortho and unflanked chlorines. This shift in activity by GAC shown here for the first time has the potential to promote greater degradation in situ by promoting accumulation of less chlorinated congeners that are generally more susceptible to complete mineralization by aerobic PCB degrading bacteria.

Effect of age, weight, and sire on embryo and fetal survival in sheep

The goal was to estimate the heritabilities and genetic variances for embryo and fetal survival (ES) in sheep along with the effect of premating ewe weight, age, and bilateral or unilateral ovulation on ES. The data consisted of 11,369 records on ovulation rate and litter size. Statistical models for ES included year and ovulation rate as fixed effects, premating ewe weight, and age as covariates, and sire of embryo, maternal grandsire (MGS), and permanent maternal environmental effects of the ewe as random effects. The variance components were estimated using REML. In ewes that survived to yr 6, the mean litter size was 1.87, 2.05, 2.01, 2.07, and 1.91 ± 0.04 in ewes of age 2, 3, 4, 5, and 6 yr, respectively. Litter size was less in ewes of age 2 and 6 yr compared to ewes of age 3, 4, and 5 yr (P < 0.01). Ovulation rate was lower at age 2 yr and increased from age 2 to 6 yr (P < 0.05). Two-year-old ewes had lower ES than 3-yr-old ewes (P < 0.01) and the probability of ES decreased after age 3 yr (P < 0.01). Thus, ES contributes significantly to lower fertility in 2-yr-old ewes. In ewes with high ovulation rates (i.e., 5 corpora lutea, CL), more balanced ovulations (i.e., 2 or 3 CL on each ovary) tended (P = 0.06) to be associated with increased ES. A quadratic relationship was observed between ewe weight and litter size (P < 0.01) and a positive linear relationship between premating ewe weight and ovulation rate (P < 0.01). A quadratic effect of ewe weight on ES was observed, with decreased ES for low and high ewe weights (P < 0.01). The optimal ewe weight for ES increased with ovulation rate, which is consistent with the requirement of greater body reserves for maintaining a larger number of fetuses during gestation. A quadratic relationship between ewe weight and the probability that a ewe is able to maintain a pregnancy was also observed (P < 0.05). Pregnancy loss is due to failure of the embryo or fetus or failure of the dam to maintain the pregnancy. The sire of the embryo only influences the embryo, whereas the MGS influences both the ewe and the embryo. The heritability for the direct additive effect on ES in ewes that lambed was 0.0081 ± 0.0139, and the heritability for the maternal additive effect was 0.0447 ± 0.0242. The permanent maternal environmental variance component was significant and explained 8.5% of the phenotypic variance. Thus, genetically, the dam's ability to maintain a pregnancy has 5.5 times the effect on pregnancy loss than the embryo's ability to survive, and this, in turn, was only half the size of the permanent environmental effect. Therefore, selection among dams based on the mean embryonic survival of their embryos will provide an effective way to improve embryonic survival.

TagDock: an efficient rigid body docking algorithm for oligomeric protein complex model construction and experiment planning

We report here new computational tools and strategies to efficiently generate three-dimensional models for oligomeric biomolecular complexes in cases where there is limited experimental restraint data to guide the docking calculations. Our computational tools are designed to rapidly and exhaustively enumerate all geometrically possible docking poses for an oligomeric complex, rather than generate detailed, atomic-resolution models. Experimental data, such as interatomic distance measurements, are then used to select and refine docking poses that are consistent with the experimental restraints. Our computational toolkit is designed for use with sparse data sets to generate intermediate-resolution docking models, and utilizes distance difference matrix analysis to identify further restraint measurements that will provide maximum additional structural refinement. Thus, these tools can be used to help plan optimal residue positions for probe incorporation in labor-intensive biophysical experiments such as chemical cross-linking, electron paramagnetic resonance, or Förster resonance energy transfer spectroscopy studies. We present benchmark results for docking the collection of all 176 heterodimer protein complexes from the ZDOCK database, as well as a protein homodimer with recently collected experimental distance restraints, to illustrate the toolkit's capabilities and performance, and to demonstrate how distance difference matrix analysis can automatically identify and prioritize additional restraint measurements that allow us to rapidly optimize docking poses.

Budesonide/formoterol vs. salmeterol/fluticasone in COPD: a systematic review and adjusted indirect comparison of pneumonia in randomised controlled trials

AIMS

This analysis was designed to provide a comparison between budesonide/formoterol and salmeterol/fluticasone for the relative incidence of pneumonia adverse events, pneumonia serious adverse events and pneumonia-related mortality in patients being treated for chronic obstructive pulmonary disease.

METHODS

An initial literature search revealed no suitable head-to-head trials between budesonide/formoterol and salmeterol/fluticasone and therefore a systematic review was conducted to find randomised controlled trials providing data for input into an adjusted indirect comparison of the two combination treatments using placebo as a common comparator. The Bucher adjusted indirect comparison method was used to calculate odds ratios and 95% confidence intervals.

RESULTS

Eight salmeterol/fluticasone trials and four budesonide/formoterol trials were identified as being relevant for the analyses. The proportion of patients experiencing a pneumonia adverse event was significantly lower with budesonide/formoterol than salmeterol/fluticasone (odds ratio, 0.47; 95% confidence interval, 0.28-0.80). The proportion of patients experiencing a pneumonia serious adverse event was also significantly lower with budesonide/formoterol than salmeterol/fluticasone (odds ratio, 0.41; 95% confidence interval, 0.19-0.86). However, there were too few events to draw any firm conclusions on pneumonia-related mortality.

CONCLUSIONS

The results of the indirect comparison support the hypothesis that budesonide/formoterol is associated with fewer pneumonia events than salmeterol/fluticasone in chronic obstructive pulmonary disease. The limitations of the analysis are that the results from a single study, TORCH, have a large bearing on the overall findings of the analysis, and that there is heterogeneity in the length and the dosing of the included studies, although it does not appear that heterogeneity affected the reported results. Another important limitation is the lack of predefined diagnostic standards for pneumonia in these studies.

A linkage map of sheep chromosome X (OARX) aligned to human chromosome X (HSAX)

We have constructed a genetic linkage map of the sheep X chromosome (OARX) containing 22 new gene loci from across the human X chromosome (HSAX). The female OARX linkage map has a total length of 152.6 cM with average gene spacing of 5.5 cM. Comparison with HSAX confirms one previously reported major breakpoint and inversion, and other minor rearrangements between OARX and HSAX. Comparison of the linkage map with sheep sequence data OAR 1.0 reveals a different arrangement of markers on the q arm, which may more accurately reflect the genuine arrangement of this region.

Determination of structural models of the complex between the cytoplasmic domain of erythrocyte band 3 and ankyrin-R repeats 13-24

The adaptor protein ankyrin-R interacts via its membrane binding domain with the cytoplasmic domain of the anion exchange protein (AE1) and via its spectrin binding domain with the spectrin-based membrane skeleton in human erythrocytes. This set of interactions provides a bridge between the lipid bilayer and the membrane skeleton, thereby stabilizing the membrane. Crystal structures for the dimeric cytoplasmic domain of AE1 (cdb3) and for a 12-ankyrin repeat segment (repeats 13-24) from the membrane binding domain of ankyrin-R (AnkD34) have been reported. However, structural data on how these proteins assemble to form a stable complex have not been reported. In the current studies, site-directed spin labeling, in combination with electron paramagnetic resonance (EPR) and double electron-electron resonance, has been utilized to map the binding interfaces of the two proteins in the complex and to obtain inter-protein distance constraints. These data have been utilized to construct a family of structural models that are consistent with the full range of experimental data. These models indicate that an extensive area on the peripheral domain of cdb3 binds to ankyrin repeats 18-20 on the top loop surface of AnkD34 primarily through hydrophobic interactions. This is a previously uncharacterized surface for binding of cdb3 to AnkD34. Because a second dimer of cdb3 is known to bind to ankyrin repeats 7-12 of the membrane binding domain of ankyrin-R, the current models have significant implications regarding the structural nature of a tetrameric form of AE1 that is hypothesized to be involved in binding to full-length ankyrin-R in the erythrocyte membrane.

Impact of distal mutation on hydrogen transfer interface and substrate conformation in soybean lipoxygenase

The impact of distal mutation on the hydrogen transfer interface properties and on the substrate mobility, conformation, and orientation in soybean lipoxygenase-1 (SLO) is examined. SLO catalyzes a hydrogen abstraction reaction that occurs by a proton-coupled electron transfer mechanism. Mutation of isoleucine 553 to less bulky residues has been found experimentally to increase the magnitude and temperature dependence of the kinetic isotope effect for this reaction. This residue borders the linoleic acid substrate but is approximately 15 A from the active site iron. In the present study, we model these experimental data with a vibronically nonadiabatic theory and perform all-atom molecular dynamics simulations on the complete solvated wild-type and mutant enzymes. Our calculations indicate that the proton transfer equilibrium distance increases and the associated frequency decreases as residue 553 becomes less bulky. The molecular dynamics simulations illustrate that this mutation impacts the mobility, geometrical conformation, and orientation of the linoleic acid within the active site. In turn, these effects alter the proton donor-acceptor equilibrium distance and frequency, leading to the experimentally observed changes in the magnitude and temperature dependence of the kinetic isotope effect. This study provides insight into how the effects of distal mutations may be transmitted in enzymes to ultimately impact the catalytic rates.

Budesonide/formoterol for maintenance and reliever therapy of asthma: a meta analysis of randomised controlled trials

OBJECTIVES

To compare the effectiveness of budesonide/formoterol (Symbicort) for Maintenance and Reliever Therapy (Symbicort SMART) Turbuhaler with twice daily inhaled corticosteroid (ICS) treatment, alone or in combination with a long-acting beta(2)-agonist (LABA).

METHODS

Meta analysis of randomised controlled trials (RCTs) using a fixed effects model. RCTs were included if the comparator with budesonide/formoterol for maintenance and relief had the equivalent, or up to fourfold higher, maintenance dose of ICS. The primary outcome was the incidence of severe exacerbation (oral glucocorticosteroid treatment for > or = 3 days, emergency visit and/or hospitalisation).

RESULTS

Of the seven RCTs available six met the inclusion criteria. Risk of severe exacerbations was significantly reduced: 41% vs. higher-dose budesonide alone [relative risk (RR) 0.59, 95% confidence interval (95% CI): 0.51-0.68, p < 0.00001]; 43% vs. equivalent dose budesonide/formoterol as maintenance twice daily (RR 0.57, 95% CI: 0.49-0.66, p < 0.00001); 24% vs. higher-dose salmeterol/fluticasone twice daily (RR 0.76, 95% CI: 0.64-0.90, p = 0.002); and 26% vs. higher-dose budesonide/formoterol twice daily (RR 0.74, 95% CI: 0.58-0.96, p = 0.02). Significant heterogeneity was not detected in the primary analyses (p > 0.1). Secondary analyses also demonstrated that budesonide/formoterol for maintenance and relief reduced the most severe exacerbations, resulting in less hospitalisations/accident and emergency visits than higher-dose budesonide, equivalent dose budesonide/formoterol and higher-dose salmeterol/fluticasone twice daily.

CONCLUSION

Budesonide/formoterol for maintenance and relief is significantly more effective at reducing severe exacerbations than higher-dose ICS alone, or in combination with a LABA. This has important implications for treating uncontrolled patients at steps 2 and 3 of the joint BTS/SIGN guidelines.

Driving force dependence of rates for nonadiabatic proton and proton-coupled electron transfer: conditions for inverted region behavior

The driving force dependence of the rate constants for nonadiabatic electron transfer (ET), proton transfer (PT), and proton-coupled electron transfer (PCET) reactions is examined. Inverted region behavior, where the rate constant decreases as the reaction becomes more exoergic (i.e., as DeltaG(0) becomes more negative), has been observed experimentally for ET and PT. This behavior was predicted theoretically for ET but is not well understood for PT and PCET. The objective of this Letter is to predict the experimental conditions that could lead to observation of inverted region behavior for PT and PCET. The driving force dependence of the rate constant is qualitatively different for PT and PCET than for ET because of the high proton vibrational frequency and substantial shift between the reactant and product proton vibrational wave functions. As a result, inverted region behavior is predicted to be experimentally inaccessible for PT and PCET if only the driving force is varied. This behavior may be observed for PT over a limited range of rates and driving forces if the solvent reorganization energy is low enough to cause observable oscillations. Moreover, this behavior may be observed for PT or PCET if the proton donor-acceptor distance increases as DeltaG(0) becomes more negative. Thus, a plausible explanation for experimentally observed inverted region behavior for PT or PCET is that varying the driving force also impacts other properties of the system, such as the proton donor-acceptor distance.

Systematic review: standard- and double-dose proton pump inhibitors for the healing of severe erosive oesophagitis -- a mixed treatment comparison of randomized controlled trials

BACKGROUND

No randomized controlled trial (RCT) has compared all European-licensed standard- and double-dose PPIs for the healing of severe erosive oesophagitis.

AIM

To compare the effectiveness of licensed doses of PPIs for healing severe erosive oesophagitis (i.e. esomeprazole 40 mg, lansoprazole 30 mg, omeprazole 20 mg and 40 mg, pantoprazole 40 mg and rabeprazole 20 mg).

METHODS

Systematic review of CENTRAL, EMBASE and MEDLINE for RCTs in patients with erosive oesophagitis (completed October 2008). Endoscopically verified healing rates at 4 and 8 weeks were extracted and re-calculated if not analysed by intention-to-treat. A mixed treatment comparison was used to combine direct treatment comparisons with indirect trial evidence while maintaining randomization. Odds ratios (OR) are reported compared to omeprazole 20 mg.

RESULTS

A total of 3021 papers were identified in the literature search; 12 were of sufficient quality to be included in the analysis. Insufficient data were available to included rabeprazole. Esomeprazole 40 mg was found to provide significantly higher healing rates at 4 weeks [OR 1.84, 95% Credible Interval (95% CrI): 1.50 to 2.22] and 8 weeks (OR 1.91, 95% CrI: 1.13 to 2.88). No other PPI investigated had significantly higher healing rates than omeprazole 20 mg.

CONCLUSION

Esomeprazole 40 mg consistently demonstrates higher healing rates compared with licensed standard- and double-dose PPIs.

Indirect comparisons of treatments based on systematic reviews of randomised controlled trials

BACKGROUND

Randomised controlled trials are the most effective way to differentiate between the effects of competing interventions. However, head-to-head studies are unlikely to have been conducted for all competing interventions.

AIM

Evaluation of different methodologies used to indirectly compare interventions based on meta analyses of randomised controlled trials.

METHODS

Systematic review of Cochrane Database of Systematic Reviews, Cochrane Methodology Register, EMBASE and MEDLINE for reports including meta analyses that contained an indirect comparison. Searching was completed in July 2007. No restriction was placed on language or year of publication.

RESULTS

Sixty-two papers identified contained indirect comparisons of treatments. Five different methodologies were employed: comparing point estimates (1/62); comparing 95% confidence intervals (26/62); performing statistical tests on summary estimates (8/62); indirect comparison using a single common comparator (20/62); and mixed treatment comparison (MTC) (7/62). The only methodologies that provide an estimate of the difference between the interventions under consideration and a measure of the uncertainty around that estimate are indirect comparison using a single common comparator and MTC. The MTC might have advantages over other approaches because it is not reliant on a single common comparator and can incorporate the results of direct and indirect comparisons into the analysis. Indirect comparisons require an underlying assumption of consistency of evidence. Utilising any of the methodologies when this assumption is not true can produce misleading results.

CONCLUSIONS

Use of either indirect comparison using a common comparator or MTC provides estimates for use in decision making, with the preferred methodology being dependent on the available data.

Is exocrine pancreatic insufficiency in adult coeliac disease a cause of persisting symptoms?

BACKGROUND

Patients with coeliac disease may have diarrhoea despite being on a gluten-free diet.

AIM

To assess whether exocrine pancreatic insufficiency causes persisting symptoms compared with controls, we determined whether pancreatic enzyme supplementation provided symptomatic benefit in coeliac patients with chronic diarrhoea.

METHODS

Patients (n = 259) were subdivided into four groups: (a) new coeliac disease (n = 57), (b) coeliac disease patients on a gluten-free diet without gastrointestinal symptoms (n = 86), (c) coeliac disease patients on a gluten-free diet with chronic diarrhoea (n = 66) and (d) patients with chronic diarrhoea without coeliac disease (n = 50). Stool frequency and weight, before and after treatment with pancreatic enzyme supplementation were recorded.

RESULTS

The prevalence of a low faecal elastase-1 within the groups was: group (A) six of 57 (11%), group (B) five of 86 (6%), group (C) 20 of 66 (30%) and group (D) two of 50 (4%). Low faecal elastase-1 was more frequent in coeliac disease patients with chronic diarrhoea vs. other subgroups of coeliac disease (P < or = 0.0001) and controls (P < or = 0.0003). In 18 of 20 stool frequency reduced following pancreatic enzyme supplementation from four per day to one (P < or = 0.001). No weight increase (P = 0.3) was observed.

CONCLUSIONS

Low faecal elastase is common in patients with coeliac disease and chronic diarrhoea, suggesting exocrine pancreatic insufficiency. In this group of patients, pancreatic enzyme supplementation may provide symptomatic benefit.

Systematic review: proton pump inhibitors (PPIs) for the healing of reflux oesophagitis - a comparison of esomeprazole with other PPIs

BACKGROUND

No randomized controlled trial has compared all the licensed standard dose proton pump inhibitors in the healing of reflux oesophagitis.

AIM

To compare the effectiveness of esomeprazole with licensed standard dose proton pump inhibitors for healing of reflux oesophagitis (i.e. lansoprazole 30 mg, omeprazole 20 mg, pantoprazole 40 mg and rabeprazole 20 mg).

METHODS

Systematic review of CENTRAL, BIOSIS, EMBASE and MEDLINE for randomized controlled trials in patients with reflux oesophagitis. Searching was completed in February 2005. Data on endoscopic healing rates at 4 and 8 weeks were extracted and re-analysed if not analysed by intention-to-treat. Meta-analysis was conducted using a fixed effects model.

RESULTS

Of 133 papers identified in the literature search, six were of sufficient quality to be included in the analysis. No studies were identified comparing rabeprazole with esomeprazole. A meta-analysis of healing rates of esomeprazole 40 mg compared with standard dose proton pump inhibitors gave the following results: at 4 weeks [relative risk (RR) 0.92; 95% CI: 0.90, 0.94; P < 0.00001], and 8 weeks (RR 0.95; 95% CI: 0.94, 0.97; P < 0.00001). Publication bias did not have a significant impact on the results. The results were robust to changes in the inclusion/exclusion criteria and using a random effects model.

CONCLUSION

Esomeprazole consistently demonstrates higher healing rates when compared with standard dose proton pump inhibitors.

The effects of early syphilis on CD4 counts and HIV-1 RNA viral loads in blood and semen

OBJECTIVE

To examine the effect of early syphilis on blood and semen plasma HIV-1 viral loads and CD4 counts.

METHODS

In a retrospective case-control study, blood plasma HIV-1 viral loads and CD4 counts in cases during early syphilis (n = 63, 27 receiving antiretroviral therapy) were compared to those before and after syphilis and with controls with non-systemic acute sexually transmitted infections (STI) (n = 104, 39 receiving antiretroviral therapy). In a prospective substudy in those not receiving antiretroviral therapy, semen plasma viral loads during early syphilis (n = 13) were compared with those 1 month, 3 months, and 6 months after treatment for syphilis and with controls with no STIs (n = 20).

RESULTS

Retrospective study: CD4 counts were similar in cases (median 410, n = 139 counts) during early syphilis compared to before (485, n = 80) and after (475, n = 88). In a secondary analysis, a drop in CD4 count (21%) among those with early latent syphilis was observed compared with controls. Blood plasma viral loads did not change significantly overall or in those with primary, secondary, or early latent syphilis. Effects were similar on or off antiretroviral therapy. Prospective study: blood and semen viral loads were slightly higher in cases compared with controls but treatment of early syphilis did not reduce either.

CONCLUSIONS

We detected no association between early syphilis and changes in blood or semen viral load or CD4 count. Increased HIV-1 infectivity associated with early syphilis is unlikely to be associated with increased levels of HIV-1 RNA in blood or semen.

Lay public's understanding of equipoise and randomisation in randomised controlled trials

OBJECTIVES

To research the lay public's understanding of equipoise and randomisation in randomised controlled trials (RCTs) and to look at why information on this may not be not taken in or remembered, as well as the effects of providing information designed to overcome barriers.

DESIGN

Investigations were informed by an update of systematic review on patients' understanding of consent information in clinical trials, and by relevant theory and evidence from experimental psychology. Nine investigations were conducted with nine participants.

SETTING

Access (return to education), leisure and vocational courses at Further Education Colleges in the Midlands, UK.

PARTICIPANTS

Healthy adults with a wide range of educational backgrounds and ages.

INVESTIGATIONS

Participants read hypothetical scenarios and wrote brief answers to subsequent questions. Sub-samples of participants were interviewed individually to elaborate on their written answers. Participants' background assumptions concerning equipoise and randomisation were examined and ways of helping participants recognise the scientific benefits of randomisation were explored.

MAIN OUTCOME MEASURES

Judgments on allocation methods; treatment preferences; the acceptability of random allocation; whether or not individual doctors could be completely unsure about the best treatment; whether or not doctors should reveal treatment preferences under conditions of collective equipoise; and how sure experts would be about the best treatment following random allocation vs doctor/patient choice. Assessments of understanding hypothetical trial information.

RESULTS

Recent literature continues to report trial participants' failure to understand or remember information about randomisation and equipoise, despite the provision of clear and readable trial information leaflets. In current best practice, written trial information describes what will happen without offering accessible explanations. As a consequence, patients may create their own incorrect interpretations and consent or refusal may be inadequately informed. In six investigations, most participants identified which methods of allocation were random, but judged the random allocation methods to be unacceptable in a trial context; the mere description of a treatment as new was insufficient to engender a preference for it over a standard treatment; around half of the participants denied that a doctor could be completely unsure about the best treatment. A majority of participants judged it unacceptable for a doctor to suggest letting chance decide when uncertain of the best treatment, and, in the absence of a justification for random allocation, participants did not recognise scientific benefits of random allocation over normal treatment allocation methods. The pattern of results across three intervention studies suggests that merely supplementing written trial information with an explanation is unlikely to be helpful. However, when people manage to focus on the trial's aim of increasing knowledge (as opposed to making treatment decisions about individuals), and process an explanation actively, they may be helped to understand the scientific reasons for random allocation.

CONCLUSIONS

This research was not carried out in real healthcare settings. However, participants who could correctly identify random allocation methods, yet judged random allocation unacceptable, doubted the possibility of individual equipoise and saw no scientific benefits of random allocation over doctor/patient choice, are unlikely to draw upon contrasting views if invited to enter a real clinical trial. This suggests that many potential trial participants may have difficulty understanding and remembering trial information that conforms to current best practice in its descriptions of randomisation and equipoise. Given the extent of the disparity between the assumptions underlying trial design and the assumptions held by the lay public, the solution is unlikely to be simple. Nevertheless, the results suggest that including an accessible explanation of the scientific benefits of randomisation may be beneficial provided potential participants are also enabled to reflect on the trial's aim of advancing knowledge, and to think actively about the information presented. Further areas for consideration include: the identification of effective combinations of written and oral information; helping participants to reflect on the aim of advancing knowledge; and an evidence-based approach to leaflet construction.

The effect of temperature on food poisoning: a time-series analysis of salmonellosis in ten European countries

We investigated the relationship between environmental temperature and reported Salmonella infections in 10 European populations. Poisson regression adapted for time-series data was used to estimate the percentage change in the number of cases associated with a 1 degree C increase in average temperature above an identified threshold value. We found, on average, a linear association between temperature and the number of reported cases of salmonellosis above a threshold of 6 degrees C. The relationships were very similar in The Netherlands, England and Wales, Switzerland, Spain and the Czech Republic. The greatest effect was apparent for temperature 1 week before the onset of illness. The strongest associations were observed in adults in the 15-64 years age group and infection with Salmonella Enteritidis (a serotype of Salmonella). Our findings indicate that higher temperatures around the time of consumption are important and reinforce the need for further education on food-handling behaviour.

Antibody responses to HPV6b E polyproteins and production of monoclonal antibodies

A range of fusion constructs (expressed in Escherichia coli) were produced that contained two or more HPV6b E proteins, producing a single continuous amino acid sequence corresponding to the sequences of the individual E proteins. The constructs also included a C-terminal hexahistidine tag fused in-frame to aid purification. The fusion proteins (polyproteins) were semipurified by Ni(++) metal affinity chromatography under denaturing conditions. Immunization of BALB/c mice with these polyproteins resulted in the production of specific E protein antibodies. The draining lymph nodes from these mice were used to produce monoclonal antibodies (MAbs). The specificity of the polyclonal and MAbs was confirmed by immunoblotting and by screening for reaction with a series of synthetic peptides of E proteins. HPV E polyproteins were found to be immunogenic and immunization with the polyproteins resulted in specific antibody responses to the component E proteins.

Structural basis for the spotted appearance of amphibian neuromuscular junctions stained for synaptic vesicles

We have compared the distribution of vesicles in amphibian motor nerve terminals determined by electron microscopy and by functional labeling with the styryl dye, FM2-10. Our aim was to resolve apparent discrepancies in the literature on the distribution of vesicles determined by the two procedures. Electron photomicrographs of non-serial cross sections of terminal branches were analyzed by stereological procedures to obtain indices of the terminal and vesicle areas. Terminal cross sectional area varied 3-fold on average along terminal branches and was largest particularly when active zone was present in the section. The vesicle area index (a measure of vesicle abundance) was highly correlated with the terminal area index, suggesting that the average density of vesicles is constant throughout the branches. When the data were separated according to whether active zone was present or not in a section, we found a small (26%) but significant increase in the average density of vesicles in active zone compared with non-active zone regions in the terminal. The distribution of spots along terminal branches following vesicle staining with FM2-10, as well as with antibodies to vesicle proteins, suggested that vesicles were distributed in highly concentrated clusters. However, the degree of variation between spot and inter-spot staining intensities found with the FM-dye was similar in magnitude to that for terminal cross sectional area determined from the electron microscopy. We conclude that the spotty pattern of stained vesicles seen with the optical microscope results primarily from vesicle accumulations associated with terminal varicosities.

Systematic review of proton pump inhibitors for the acute treatment of reflux oesophagitis

BACKGROUND

Esomeprazole is a new proton pump inhibitor, which has been compared to omeprazole for the treatment of reflux oesophagitis in clinical trials.

AIM

To compare the effectiveness of esomeprazole with the recommended dose of proton pump inhibitors in the healing of reflux oesophagitis, using omeprazole as a common comparator.

METHODS

Systematic review of randomized controlled trials. Extraction and re-analysis of data to provide 'intention-to-treat' results. Meta-analysis using a Fixed Effects model.

RESULTS

A meta-analysis of healing rates of esomeprazole 40 mg compared to omeprazole 20 mg gave the following results: at 4 weeks (relative risk 1.14; 95% CI: 1.10, 1.18) and 8 weeks (RR 1.08; 95%CI: 1.05, 1.10). Other proton pump inhibitors compared to omeprazole 20 mg are as follows: lansoprazole 30 mg at 4 weeks (RR 1.02; 95%CI: 0.97, 1.08) and 8 weeks (RR 1.01; 95%CI: 0.97, 1.06); pantoprazole 40 mg at 4 weeks (RR 0.99; 95%CI: 0.91, 1.07) and 8 weeks (RR 0.98; 95%CI: 0.93, 1.04); rabeprazole 20 mg at 4 weeks (RR 1.00; 95%CI: 0.87, 1.14) and 8 weeks (RR 0.98; 95%CI: 0.91, 1.05).

CONCLUSIONS

Esomeprazole has demonstrated higher healing rates than omeprazole at 4 and 8 weeks. Other proton pump inhibitors (lansoprazole, pantoprazole and rabeprazole) have not shown higher healing rates when compared with omeprazole.

IL-1 genotype and adult periodontitis among young New Zealanders

Several recent studies have investigated the association between interleukin-1 genotype and periodontitis in clinical samples, where generalizability is an issue. The aim of this study was to investigate the association between adult periodontitis and IL-1 genotype in a population-based sample of 26-year-olds. Based on probing depth (PD) measurements, participants were divided into three disease groups: "Severe" (1+ teeth with 5+mm PD; N = 25), "Moderate" (2+ teeth with 4+mm PD; N = 36), and "Controls" (the remainder; N = 800). The "periodontitis-associated genotype" (PAG; Kornman et al., 1997) was present in 20.0% of the "Severe" group and in 34.8% of "Controls", whereas the IL-1A(+4845) [1,1]/IL-1B(+3953) [2,2] genotype was present in 12.0% and 0.9%, respectively. After controlling for sex, smoking status, and plaque levels, we found that those with IL-1B(+3953) [1,1]/IL-1A(+4845) [2,2] had 12.3 times the odds of being in the "Severe" group. Analysis of these data suggests that the IL-1A(+4845) [1,1]/IL-1B(+3953) [2,2] genotype is associated with periodontal disease in this young population. Future periodontal data collections as this cohort ages are required to confirm the predictive value of that genotype.

Clinical trials. A place for randomization in the interval between the end of recruitment and availability of results

There is a time delay between the final recruitment of patients to a randomized controlled trial and the publication of results. The practical options available to decision makers during this gap can be listed according to whether all treatments are already widely available or whether at least one has been restricted to the trial. When the treatments are already in widespread use, the options are simply either to stop randomizing or to continue. When one trial treatment is restricted, there are further options: a) withdraw the restricted treatment altogether, pending the final analysis; b) continue to offer randomization, with a view to providing further data should these be needed; or c) make the intervention widely available to patients who would have previously been eligible for the trial. In this paper, we discuss the relative advantages and disadvantages of each option and discuss their attendant ethical implications. In particular, we suggest that continuing randomization is an option worthy of serious consideration. Randomizing patients acts as a "hedge" against the need for more data, given that sample size calculation is an inexact science. However, patients must be made aware of the basis on which randomization is offered.

Are randomized clinical trials good for us (in the short term)? Evidence for a "trial effect"

OBJECTIVE

To assess whether there is evidence that randomized controlled trials are systematically beneficial, or harmful, for patients. In other words, is there a "trial effect"? If so, to examine whether the evidence sheds light on the likely sources of the difference in outcomes.

METHODS

Systematic review of the literature.

RESULTS

We set out in some detail potential sources of a "trial effect" and potential biases. We found only 14 research articles (covering more than 21 trials) with relevant primary data. We extracted, with difficulty, quantitative data-sets from the articles, and classified these according to likely source of any apparent trial effect. The categories used were: differences in prognosis; superior treatment in the trial; and "protocol/Hawthorne effect" (benefit from improved routine care within a trial).

ANALYSIS

The evidence available is limited in breadth (coming largely from cancer trials) and quality, as well as quantity. There is weak evidence to suggest that clinical trials have a positive effect on the outcome of participants. This does not appear to depend strongly on the trial demonstrating that an experimental treatment is superior. However, benefit to participants is less evident where scope for a "protocol/Hawthorne effect" was apparently limited (because there was no effective routine treatment or because the comparison group also received protocol care). A form of bias, arising if clinicians who tend to recruit to trials also tend to be better clinicians, could also explain these results.

CONCLUSION

While the evidence is not conclusive, it is more likely that clinical trials have a positive rather than a negative effect on the outcome of patients. In the limited data available, the effect seems to be larger in trials where an effective treatment already exists and is included in the trial protocol.

RECOMMENDATION

That carefully researched treatment protocols, and monitoring of outcomes, be used for all patients, not just those in trials.

Can unequal be more fair? A response to Andrew Avins

In this paper, we respond to Andrew Avins's recent review of methods whose use he advocates in clinical trials, to make them more ethical. He recommends in particular, "unbalanced randomisation". However, we argue that, before such a recommendation can be made, it is important to establish why unequal randomisation might offer ethical advantages over equal randomisation, other things being equal. It is important to make a pragmatic distinction between trials of treatments that are already routinely available and trials of restricted treatments. We conclude that unequal randomisation could, indeed, be an ethical compromise between protecting the interests of participants and those of society.

Measurement of gastric residual volume: state of the science

This literature review substantiates that there is confusion regarding what constitutes excessive gastric residual volume in adult tube-fed patients. Only one research study regarding gastric residuals was located; it indicated that 200 ml for a nasogastric tube and 100 ml for a gastrostomy tube should cause concern. The implications of these findings for adult-health nurses are discussed.

Efficient induction of cell death by adenoviruses requires binding of E1B55k and p53

The use of an Elb55k-deficient adenovirus, ONYX-015, to selectively target tumor cells containing a mutated p53 gene has produced promising results. However, recent reports have questioned the selectivity of this virus, showing that ONYX-015 can replicate in cells containing a wild-type p53 and that p53 may actually be required for cell death. To address these apparent contradictions in the literature, we infected a number of mutant and wild-type p53-containing cell lines with ONYX-015 and wild-type adenovirus and observed their death profiles up to 10 days postinfection. We demonstrate that two distinct cell death phenotypes exist, one of which is rapid and dependent on the presence of p53 and one of which is p53 independent. Using adenoviruses expressing E1b55k proteins deficient in their ability to bind p53, we show that formation of a complex between p53 and the adenoviral Elb55k protein is necessary for the activation of the rapid cell death pathway. In the absence of p53 or the absence of complex formation between p53 and Elb55k, cell death is delayed considerably. These data suggest three things: that the selectivity of killing appears to be dependent on the presence of the E1b55k/p53 complex; that viruses lacking Elb55k (such as ONYX-015) kill cells in a delayed manner independent of p53; and that binding of E1b55k to p53 does not merely serve to inactivate p53, but rather is required for the induction of rapid cell death. The components of this complex that lead to rapid cell death remain to be determined.

Informed consent for clinical trials: in search of the "best" method

OBJECTIVE

To review the literature on comparisons between different methods of obtaining informed consent for clinical trials.

DESIGN

Eight hundred and twelve articles were traced, in the process of conducting a systematic review of the ethics of clinical trials, by searching a number of sources: bibliographic databases (Medline, Psychlit and BIDS science and social science indices), hand searches, personal contacts, an original collection and a systematic follow-up of reference lists. Fourteen research reports were found which provided comparative data on different methods of obtaining informed consent. Eleven of these used a randomised design. Studies were classified according to three outcome measures (anxiety, consent rate and understanding).

RESULTS

The results of the various studies suggest that giving people more information and more time to reflect tends to be associated with a lower consent rate. There seems to be an optimal level of information about side-effects such that patients are not overburdened by detail, while grasping the most important risks. More information in general is associated with greater awareness of the research nature of the trial, voluntariness of participation, right to withdraw and (available) alternative treatments. This result does not, however, extend to explanations of the concept of randomisation on which the literature is contradictory--sometimes more information is associated with increased understanding of the concept and sometimes it is not. Although divulging less information seems to be associated with less anxiety, there is evidence of an interaction with knowledge--high levels of knowledge are significantly associated with less anxiety, irrespective of consent method. The more that patients know before they are invited to participate in a trial, the better equipped they are to cope with the informed consent procedure.

CONCLUSION

There is some evidence to suggest that there is an optimal amount of information which enhances patient understanding and which might, in turn, reduce anxiety. However. the studies were not altogether conclusive. More work needs to be carried out, especially on public understanding of science and on how different ways of explaining scientific concepts affect that understanding.