A role for solvents in the toxicity of agricultural organophosphorus pesticides

Organophosphorus (OP) insecticide self-poisoning is responsible for about one-quarter of global suicides. Treatment focuses on the fact that OP compounds inhibit acetylcholinesterase (AChE); however, AChE-reactivating drugs do not benefit poisoned humans. We therefore studied the role of solvent coformulants in OP toxicity in a novel minipig model of agricultural OP poisoning. Gottingen minipigs were orally poisoned with clinically relevant doses of agricultural emulsifiable concentrate (EC) dimethoate, dimethoate active ingredient (AI) alone, or solvents. Cardiorespiratory physiology and neuromuscular (NMJ) function, blood AChE activity, and arterial lactate concentration were monitored for 12h to assess poisoning severity. Poisoning with agricultural dimethoate EC40, but not saline, caused respiratory arrest within 30 min, severe distributive shock and NMJ dysfunction, that was similar to human poisoning. Mean arterial lactate rose to 15.6 [SD 2.8] mM in poisoned pigs compared to 1.4 [0.4] in controls. Moderate toxicity resulted from poisoning with dimethoate AI alone, or the major solvent cyclohexanone. Combining dimethoate with cyclohexanone reproduced severe poisoning characteristic of agricultural dimethoate EC poisoning. A formulation without cyclohexanone showed less mammalian toxicity. These results indicate that solvents play a crucial role in dimethoate toxicity. Regulatory assessment of pesticide toxicity should include solvents as well as the AIs which currently dominate the assessment. Reformulation of OP insecticides to ensure that the agricultural product has lower mammalian toxicity could result in fewer deaths after suicidal ingestion and rapidly reduce global suicide rates.

Memantine for dementia in adults older than 40 years with Down's syndrome (MEADOWS): a randomised, double-blind, placebo-controlled trial

BACKGROUND

Prevalence of Alzheimer's disease in people with Down's syndrome is very high, and many such individuals who are older than 40 years have pathological changes characteristic of Alzheimer's disease. Evidence to support treatment with Alzheimer's drugs is inadequate, although memantine is beneficial in transgenic mice. We aimed to assess safety and efficacy of memantine on cognition and function in individuals with Down's syndrome.

METHODS

In our prospective randomised double-blind trial, we enrolled adults (>40 years) with karyotypic or clinically diagnosed Down's syndrome, with and without dementia, at four learning disability centres in the UK and Norway. We randomly allocated participants (1:1) to receive memantine or placebo for 52 weeks by use of a computer-generated sequence and a minimisation algorithm to ensure balanced allocation for five prognostic factors (sex, dementia, age group, total Down's syndrome attention, memory, and executive function scales [DAMES] score, and centre). The primary outcome was change in cognition and function, measured with DAMES scores and the adaptive behaviour scale (ABS) parts I and II. We analysed differences in DAMES and ABS scores between groups with analyses of covariance or quantile regression in all patients who completed the 52 week assessment and had available follow-up data. This study is registered, number ISRCTN47562898.

FINDINGS

We randomly allocated 88 patients to receive memantine (72 [82%] had DAMES data and 75 [85%] had ABS data at 52 weeks) and 85 to receive placebo (74 [87%] and 73 [86%]). Both groups declined in cognition and function but rates did not differ between groups for any outcomes. After adjustment for baseline score, there were non-significant differences between groups of -4·1 (95% CI -13·1 to 4·8) in DAMES scores, -8·5 (-20·1 to 3·1) in ABS I scores, and 2·0 (-7·2 to 11·3) in ABS II scores, all in favour of controls. 10 (11%) of 88 participants in the memantine group and six (7%) of 85 controls had serious adverse events (p=0·33). Five participants in the memantine group and four controls died from serious adverse events (p=0·77).

INTERPRETATION

There is a striking absence of evidence about pharmacological treatment of cognitive impairment and dementia in people older than 40 years with Down's syndrome. Despite promising indications, memantine is not an effective treatment. Therapies that are effective for Alzheimer's disease are not necessarily effective in this group of patients.

FUNDING

Lundbeck.

Immunogenicity and tolerability of recombinant serogroup B meningococcal vaccine administered with or without routine infant vaccinations according to different immunization schedules: a randomized controlled trial

CONTEXT

In the absence of an effective vaccine, serogroup B Neisseria meningitidis (MenB) remains a major cause of invasive disease in early childhood in developed countries.

OBJECTIVE

To determine the immunogenicity and reactogenicity of a multicomponent MenB vaccine (4CMenB) and routine infant vaccines when given either concomitantly or separately.

DESIGN, SETTING, AND PARTICIPANTS

Phase 2b, multicenter, open-label, parallel-group, randomized controlled study of 1885 infants enrolled at age 2 months from August 2008 to July 2010 in Europe.

INTERVENTION

Participants were randomized 2:2:1:1 to receive (1) 4CMenB at 2, 4, and 6 months with routine vaccines (7-valent pneumococcal and combined diphtheria, tetanus, acellular pertussis, inactivated polio, hepatitis B, Haemophilus influenzae type b vaccines); (2) 4CMenB at 2, 4, and 6 months and routine vaccines at 3, 5, and 7 months; (3) 4CMenB with routine vaccines at 2, 3, and 4 months; or (4) routine vaccines alone at 2, 3, and 4 months.

MAIN OUTCOME MEASURES

Percentage of participants with human complement serum bactericidal activity (hSBA) titer of 1:5 or greater against 3 MenB strains specific for vaccine antigens (NZ98/254, 44/76-SL, and 5/99).

RESULTS

After three 4CMenB vaccinations, 99% or more of infants developed hSBA titers of 1:5 or greater against strains 44/76-SL and 5/99. For NZ98/254, this proportion was 79% (95% CI, 75.2%-82.4%) for vaccination at 2, 4, and 6 months with routine vaccines, 86.1% (95% CI, 82.9%-89.0%) for vaccination at 2, 4, and 6 months without routine vaccines, and 81.7% (95% CI, 76.6%-86.2%) for vaccination at 2, 3, and 4 months with routine vaccines. Responses to routine vaccines given with 4CMenB were noninferior to routine vaccines alone for all antigens, except for the responses to pertactin and serotype 6B pneumococcal polysaccharide. Fever was seen following 26% (158/602) to 41% (247/607) of 4CMenB doses when administered alone, compared with 23% (69/304) to 36% (109/306) after routine vaccines given alone and 51% (306/605) to 61% (380/624) after 4CMenB and routine vaccines administered together.

CONCLUSION

A 4CMenB vaccine is immunogenic against reference strains when administered with routine vaccines at 2, 4, and 6 or at 2, 3, and 4 months of age, producing minimal interference with the response to routine infant vaccinations.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00721396.

The dependence of extracted current on discharge gas pressure in neutral beam ion sources on HL-2A tokamak

The discharge gas pressure is a key factor to influence the extracted current of ion source. In this paper, the dependence of extracted current on discharge gas pressure was investigated in detail at different arc discharge currents. The discharge gas pressure with a very broad range (0.1 Pa-2.7 Pa) was scanned for the first time. It is turned out that, with the increasing of discharge gas pressure, the extracted current increases and the arc voltage decreases at different arc currents; however, when the discharge gas pressure exceeds a certain value, the extracted current decreases. For the same discharge gas pressure, the higher the arc current, the higher the arc voltage and the extracted current are. The arc efficiency was also calculated, and its dependence on gas pressure was almost the same with the dependence of extracted current on gas pressure, but at the same discharge gas pressure, the lower the arc current, the higher the arc efficiency is and the lower the extracted current is.

Reporting of participant flow diagrams in published reports of randomized trials

Background

Reporting of the flow of participants through each stage of a randomized trial is essential to assess the generalisability and validity of its results. We assessed the type and completeness of information reported in CONSORT (Consolidated Standards of Reporting Trials) flow diagrams published in current reports of randomized trials.

Methods

A cross sectional review of all primary reports of randomized trials which included a CONSORT flow diagram indexed in PubMed core clinical journals (2009). We assessed the proportion of parallel group trial publications reporting specific items recommended by CONSORT for inclusion in a flow diagram.

Results

Of 469 primary reports of randomized trials, 263 (56%) included a CONSORT flow diagram of which 89% (237/263) were published in a CONSORT endorsing journal. Reports published in CONSORT endorsing journals were more likely to include a flow diagram (62%; 237/380 versus 29%; 26/89). Ninety percent (236/263) of reports which included a flow diagram had a parallel group design, of which 49% (116/236) evaluated drug interventions, 58% (137/236) were multicentre, and 79% (187/236) compared two study groups, with a median sample size of 213 participants. Eighty-one percent (191/236) reported the overall number of participants assessed for eligibility, 71% (168/236) the number excluded prior to randomization and 98% (231/236) the overall number randomized. Reasons for exclusion prior to randomization were more poorly reported. Ninety-four percent (223/236) reported the number of participants allocated to each arm of the trial. However, only 40% (95/236) reported the number who actually received the allocated intervention, 67% (158/236) the number lost to follow up in each arm of the trial, 61% (145/236) whether participants discontinued the intervention during the trial and 54% (128/236) the number included in the main analysis.

Conclusions

Over half of published reports of randomized trials included a diagram showing the flow of participants through the trial. However, information was often missing from published flow diagrams, even in articles published in CONSORT endorsing journals. If important information is not reported it can be difficult and sometimes impossible to know if the conclusions of that trial are justified by the data presented.

Developing risk prediction models for type 2 diabetes: a systematic review of methodology and reporting

BACKGROUND

The World Health Organisation estimates that by 2030 there will be approximately 350 million people with type 2 diabetes. Associated with renal complications, heart disease, stroke and peripheral vascular disease, early identification of patients with undiagnosed type 2 diabetes or those at an increased risk of developing type 2 diabetes is an important challenge. We sought to systematically review and critically assess the conduct and reporting of methods used to develop risk prediction models for predicting the risk of having undiagnosed (prevalent) or future risk of developing (incident) type 2 diabetes in adults.

METHODS

We conducted a systematic search of PubMed and EMBASE databases to identify studies published before May 2011 that describe the development of models combining two or more variables to predict the risk of prevalent or incident type 2 diabetes. We extracted key information that describes aspects of developing a prediction model including study design, sample size and number of events, outcome definition, risk predictor selection and coding, missing data, model-building strategies and aspects of performance.

RESULTS

Thirty-nine studies comprising 43 risk prediction models were included. Seventeen studies (44%) reported the development of models to predict incident type 2 diabetes, whilst 15 studies (38%) described the derivation of models to predict prevalent type 2 diabetes. In nine studies (23%), the number of events per variable was less than ten, whilst in fourteen studies there was insufficient information reported for this measure to be calculated. The number of candidate risk predictors ranged from four to sixty-four, and in seven studies it was unclear how many risk predictors were considered. A method, not recommended to select risk predictors for inclusion in the multivariate model, using statistical significance from univariate screening was carried out in eight studies (21%), whilst the selection procedure was unclear in ten studies (26%). Twenty-one risk prediction models (49%) were developed by categorising all continuous risk predictors. The treatment and handling of missing data were not reported in 16 studies (41%).

CONCLUSIONS

We found widespread use of poor methods that could jeopardise model development, including univariate pre-screening of variables, categorisation of continuous risk predictors and poor handling of missing data. The use of poor methods affects the reliability of the prediction model and ultimately compromises the accuracy of the probability estimates of having undiagnosed type 2 diabetes or the predicted risk of developing type 2 diabetes. In addition, many studies were characterised by a generally poor level of reporting, with many key details to objectively judge the usefulness of the models often omitted.

Randomized trial to compare bilateral vs. single internal mammary coronary artery bypass grafting: 1-year results of the Arterial Revascularisation Trial (ART)

AIMS

Observational data suggest that the use of bilateral internal mammary arteries (BIMA) during coronary artery bypass graft surgery provides superior revascularization to a single internal mammary artery (SIMA), but concerns about safety have prevented the widespread use of BIMA. The Arterial Revascularisation Trial (ART) is a randomized trial of BIMA vs. SIMA, with a primary outcome of survival at 10 years. This paper reports mortality, morbidity, and resource use data at 1 year.

METHODS AND RESULTS

Coronary artery bypass graft patients were enrolled in 28 hospitals in seven countries. Three thousand one hundred and two patients were randomly assigned to SIMA (n = 1554) or BIMA (n = 1548). The mean number of grafts was 3 for both groups. Forty per cent of the SIMA procedures and 42% of the BIMA were performed off-pump. Mortality at 30 days was 18 of 1548 (1.2%) for SIMA and 19 of 1537 (1.2%) for BIMA, and at 1 year was 36 of 1540 (2.3%) and 38 of 1529 (2.5%), respectively. The rates of stroke, myocardial infarction, and repeat revascularization were all ≤2% at 1 year and similar between the two groups. Sternal wound reconstruction was required in 0.6 and 1.9% of the SIMA and BIMA groups, respectively.

CONCLUSION

Data from ART demonstrate similar clinical outcomes for SIMA and BIMA at 1 year but BIMA grafts are associated with a small absolute increase (1.3%) in the need for sternal wound reconstruction. The results suggest that the use of BIMA grafts is feasible on a routine basis. The 10-year results of the ART will confirm whether BIMA grafting results in lower mortality and the need for repeat intervention.

TRIAL REGISTRATION

Controlled-trials.com (ISRCTN46552265).

Reporting on covariate adjustment in randomised controlled trials before and after revision of the 2001 CONSORT statement: a literature review

OBJECTIVES

To evaluate the use and reporting of adjusted analysis in randomised controlled trials (RCTs) and compare the quality of reporting before and after the revision of the CONSORT Statement in 2001.

DESIGN

Comparison of two cross sectional samples of published articles.

DATA SOURCES

Journal articles indexed on PubMed in December 2000 and December 2006.

STUDY SELECTION

Parallel group RCTs with a full publication carried out in humans and published in English

MAIN OUTCOME MEASURES

Proportion of articles reported adjusted analysis; use of adjusted analysis; the reason for adjustment; the method of adjustment and the reporting of adjusted analysis results in the main text and abstract.

RESULTS

In both cohorts, 25% of studies reported adjusted analysis (84/355 in 2000 vs 113/422 in 2006). Compared with articles reporting only unadjusted analyses, articles that reported adjusted analyses were more likely to specify primary outcomes, involve multiple centers, perform stratified randomization, be published in general medical journals, and recruit larger sample sizes. In both years a minority of articles explained why and how covariates were selected for adjustment (20% to 30%). Almost all articles specified the statistical methods used for adjustment (99% in 2000 vs 100% in 2006) but only 5% and 10%, respectively, reported both adjusted and unadjusted results as recommended in the CONSORT guidelines.

CONCLUSION

There was no evidence of change in the reporting of adjusted analysis results five years after the revision of the CONSORT Statement and only a few articles adhered fully to the CONSORT recommendations.

Note: A sampling method for quantum random bit generation

In this note, we present a new sampling method for quantum random bit generation. The new method requires only one single-photon detector and does not measure the time slots of emitted photons. A binary random bit sequence obtained is independent on the time slot of the pulses and the precision of the measurement instrument. The effect of the exclusive-or operation for eliminating the bias in the raw sequences is also discussed.

The quality of reports of randomised trials in 2000 and 2006: comparative study of articles indexed in PubMed

OBJECTIVES

To examine the reporting characteristics and methodological details of randomised trials indexed in PubMed in 2000 and 2006 and assess whether the quality of reporting has improved after publication of the Consolidated Standards of Reporting Trials (CONSORT) Statement in 2001.

DESIGN

Comparison of two cross sectional investigations. Study sample All primary reports of randomised trials indexed in PubMed in December 2000 (n=519) and December 2006 (n=616), including parallel group, crossover, cluster, factorial, and split body study designs.

MAIN OUTCOME MEASURES

The proportion of general and methodological items reported, stratified by year and study design. Risk ratios with 95% confidence intervals were calculated to represent changes in reporting between 2000 and 2006.

RESULTS

The majority of trials were two arm (379/519 (73%) in 2000 v 468/616 (76%) in 2006) parallel group studies (383/519 (74%) v 477/616 (78%)) published in specialty journals (482/519 (93%) v 555/616 (90%)). In both 2000 and 2006, a median of 80 participants were recruited per trial for parallel group trials. The proportion of articles that reported drug trials decreased between 2000 and 2006 (from 393/519 (76%) to 356/616 (58%)), whereas the proportion of surgery trials increased (51/519 (10%) v 128/616 (21%)). There was an increase between 2000 and 2006 in the proportion of trial reports that included details of the primary outcome (risk ratio (RR) 1.18, 95% CI 1.04 to 1.33), sample size calculation (RR 1.66, 95% CI 1.40 to 1.95), and the methods of random sequence generation (RR 1.62, 95% CI 1.32 to 1.97) and allocation concealment (RR 1.40, 95% CI 1.11 to 1.76). There was no difference in the proportion of trials that provided specific details on who was blinded (RR 0.91, 95% CI 0.75 to 1.10).

CONCLUSIONS

Reporting of several important aspects of trial methods improved between 2000 and 2006; however, the quality of reporting remains well below an acceptable level. Without complete and transparent reporting of how a trial was designed and conducted, it is difficult for readers to assess its conduct and validity.

Plasma and memory B-cell kinetics in infants following a primary schedule of CRM 197-conjugated serogroup C meningococcal polysaccharide vaccine

The induction of persistent protective levels of pathogen-specific antibody is an important goal of immunization against childhood infections. However, antibody persistence is poor after immunization in infancy versus later in life. Serogroup C meningococci (MenC) are an important cause of bacteraemia and meningitis in children. The use of protein-polysaccharide conjugate vaccines against MenC has been associated with a significant decline in the incidence of invasive disease. However, vaccine effectiveness is negligible by more than 1 year after a three-dose priming series in infancy and corresponds to a rapid decline in antibody following an initial immune response. The cellular mechanisms underlying the generation of persistent antibody in this age group are unclear. An essential prelude to larger studies of peripheral blood B cells is an understanding of B-cell kinetics following immunization. We measured MenC- and diphtheria-specific plasma and memory B-cell kinetics in infants receiving a CRM(197) (cross-reactive material; mutant diphtheria toxoid)-conjugated MenC vaccine at 2, 3 and 4 months of age. Plasma cell responses were more delayed after the first dose when compared with the rapid appearance of plasma cells after the third dose. Memory B cells were detectable at all time-points following the third dose as opposed to the low frequency seen following a first dose. This study provides data on B-cell kinetics following a primary schedule of immunization in young infants upon which to base further studies of the underlying cellular mechanism of humoral immunity.

A randomized trial of on-pump beating heart and conventional cardioplegic arrest in coronary artery bypass surgery patients with impaired left ventricular function using cardiac magnetic resonance imaging and biochemical markers

BACKGROUND

Beating heart coronary artery bypass grafting (CABG) improves early postoperative cardiac function in patients with normal ventricular function, but its effect in patients with impaired function is uncertain. We compared a novel hybrid technique of on-pump beating heart CABG (ONBEAT) with conventional on-pump CABG (ONSTOP) in patients with impaired ventricular function.

METHODS AND RESULTS

In a single-center randomized trial, 50 patients with impaired ventricular function were randomly assigned to ONBEAT or ONSTOP. Patients underwent cardiac magnetic resonance imaging for function and delayed hyperenhancement early and later after surgery. Serial assessment of biochemical markers was also undertaken. Preoperative characteristics were well matched; cardiac index was 2.85+/-0.53 (ONBEAT) and 2.62+/-0.59 L x min(-1) x m(-2) (ONSTOP). Early after surgery, there was a trend toward a greater reduction in end-systolic volume index in ONSTOP patients versus ONBEAT (-9+/-8 versus -4+/-11 mL x m(-2); P=0.06). The changes were sustained and significant at 6 months (-14+/-18 versus -2+/-19 mL x m(-2); P=0.04). Furthermore, the incidence of new hyperenhancement at 6 days was higher in ONBEAT patients (P=0.05), with 6 of 17 (35%) sustaining 8.2+/-5.2 g of new hyperenhancement each versus 2 of 23 (9%) in the ONSTOP group, each with 9.8+/-9.0 g (P=0.86). Finally, median area under the curve for troponin was higher in ONBEAT at 461 (interquartile range, 226 to 1141) microg/L versus 160 (interquartile range, 98 to 357) microg/L for ONSTOP (P=0.002).

CONCLUSIONS

The incidence of new irreversible myocardial injury was significantly higher in ONBEAT than in ONSTOP patients. Furthermore, at 6 months, only ONSTOP patients demonstrated an improvement in ventricular geometry. The most likely mechanism is inadequate coronary perfusion to distal myocardial territories in patients with severe proximal coronary disease.

Seroprotection against serogroup C meningococcal disease in adolescents in the United Kingdom: observational study

OBJECTIVE

To determine the persistence of bactericidal antibody titres following immunisation with serogroup C meningococcal glycoconjugate vaccine at age 6-15 years in order to examine changes in persistence of antibodies with age.

DESIGN

Observational study.

SETTING

Secondary and tertiary educational institutions in the United Kingdom.

PARTICIPANTS

Healthy adolescents aged 11-20 years previously immunised between 6 and 15 years of age with one of the three serogroup C meningococcal vaccines.

INTERVENTION

Serum obtained by venepuncture.

MAIN OUTCOME MEASURES

Percentage of participants with (rabbit complement) serum bactericidal antibody titres of at least 1:8; geometric mean titres of serogroup C meningococcal serum bactericidal antibody.

RESULTS

Five years after immunisation, 84.1% (95% confidence interval 81.6% to 86.3%) of 987 participants had a bactericidal antibody titre of at least 1:8. Geometric mean titres of bactericidal antibody were significantly lower in 11-13 year olds (147, 95% confidence interval 115 to 188) than in 14-16 year olds (300, 237 to 380) and 17-20 year olds (360, 252 to 515) (P<0.0001 for both comparisons). Within these age bands, no significant difference in geometric mean titres of bactericidal antibody between recipients of the different serogroup C meningococcal vaccines was seen. More than 70% of participants had received a vaccine from one manufacturer; in this cohort, geometric mean titres were higher in those immunised at aged 10 years or above than in those immunised before the age of 10.

CONCLUSIONS

Higher concentrations of bactericidal antibody are seen five years after immunisation with serogroup C meningococcal vaccine at age 10 years or above than in younger age groups, possibly owing to immunological maturation. This provides support for adolescent immunisation programmes to generate sustained protection against serogroup C meningococcal disease not only for the vaccine recipients but also, through the maintenance of herd immunity, for younger children.

A simplified 4-site economical intradermal post-exposure rabies vaccine regimen: a randomised controlled comparison with standard methods

BACKGROUND

The need for economical rabies post-exposure prophylaxis (PEP) is increasing in developing countries. Implementation of the two currently approved economical intradermal (ID) vaccine regimens is restricted due to confusion over different vaccines, regimens and dosages, lack of confidence in intradermal technique, and pharmaceutical regulations. We therefore compared a simplified 4-site economical PEP regimen with standard methods.

METHODS

Two hundred and fifty-four volunteers were randomly allocated to a single blind controlled trial. Each received purified vero cell rabies vaccine by one of four PEP regimens: the currently accepted 2-site ID; the 8-site regimen using 0.05 ml per ID site; a new 4-site ID regimen (on day 0, approximately 0.1 ml at 4 ID sites, using the whole 0.5 ml ampoule of vaccine; on day 7, 0.1 ml ID at 2 sites and at one site on days 28 and 90); or the standard 5-dose intramuscular regimen. All ID regimens required the same total amount of vaccine, 60% less than the intramuscular method. Neutralising antibody responses were measured five times over a year in 229 people, for whom complete data were available.

FINDINGS

All ID regimens showed similar immunogenicity. The intramuscular regimen gave the lowest geometric mean antibody titres. Using the rapid fluorescent focus inhibition test, some sera had unexpectedly high antibody levels that were not attributable to previous vaccination. The results were confirmed using the fluorescent antibody virus neutralisation method.

CONCLUSIONS

This 4-site PEP regimen proved as immunogenic as current regimens, and has the advantages of requiring fewer clinic visits, being more practicable, and having a wider margin of safety, especially in inexperienced hands, than the 2-site regimen. It is more convenient than the 8-site method, and can be used economically with vaccines formulated in 1.0 or 0.5 ml ampoules. The 4-site regimen now meets all requirements of immunogenicity for PEP and can be introduced without further studies.

TRIAL REGISTRATION

Controlled-Trials.com ISRCTN 30087513.

The magnitude of the antibody and memory B cell responses during priming with a protein-polysaccharide conjugate vaccine in human infants is associated with the persistence of antibody and the intensity of booster response

Rapid waning of anti-polysaccharide bactericidal Ab and vaccine effectiveness is observed following infant immunization with the serogroup C meningococcal (MenC) glycoconjugate vaccine. This is despite the demonstrable presence of immunological memory. Persistence of functional Ab, therefore, appears to be the key determinant of MenC conjugate vaccine effectiveness. Ab persistence is thought to depend in the short term on the survival of plasma cells generated during priming and in the longer term on the production of new Ab secreting cells from memory B cells. In this study, we found a strong association between the level of MenC-specific Ab and the frequency of memory B cells measured at 5 mo of age (1 mo after 3-dose primary immunization with MenC conjugate vaccine), and the persistence of functional Ab at one year of age. These findings suggest that these two parameters are good markers of B cell responses to priming and can be used as predictors of long term humoral immunity induced by glycoconjugate vaccines received in early infancy.

A randomised, blinded, placebo-controlled trial in dementia patients continuing or stopping neuroleptics (the DART-AD trial)

BACKGROUND

There have been increasing concerns regarding the safety and efficacy of neuroleptics in people with dementia, but there are very few long-term trials to inform clinical practice. The aim of this study was to determine the impact of long-term treatment with neuroleptic agents upon global cognitive decline and neuropsychiatric symptoms in patients with Alzheimer disease.

METHODS AND FINDINGS

DESIGN

Randomised, blinded, placebo-controlled parallel two-group treatment discontinuation trial.

SETTING

Oxfordshire, Newcastle and Gateshead, London and Edinburgh, United Kingdom.

PARTICIPANTS

Patients currently prescribed the neuroleptics thioridazine, chlorpromazine, haloperidol trifluoperazine or risperidone for behavioural or psychiatric disturbance in dementia for at least 3 mo.

INTERVENTIONS

Continue neuroleptic treatment for 12 mo or switch to an identical placebo.

OUTCOME MEASURES

Primary outcome was total Severe Impairment Battery (SIB) score. Neuropsychiatric symptoms were evaluated with the Neuropsychiatric Inventory (NPI).

RESULTS

165 patients were randomised (83 to continue treatment and 82 to placebo, i.e., discontinue treatment), of whom 128 (78%) commenced treatment (64 continue/64 placebo). Of those, 26 were lost to follow-up (13 per arm), resulting in 51 patients per arm analysed for the primary outcome. There was no significant difference between the continue treatment and placebo groups in the estimated mean change in SIB scores between baseline and 6 mo; estimated mean difference in deterioration (favouring placebo) -0.4 (95% confidence interval [CI] -6.4 to 5.5), adjusted for baseline value (p = 0.9). For neuropsychiatric symptoms, there was no significant difference between the continue treatment and placebo groups (n = 56 and 53, respectively) in the estimated mean change in NPI scores between baseline and 6 mo; estimated mean difference in deterioration (favouring continue treatment) -2.4 (95% CI -8.2 to 3.5), adjusted for baseline value (p = 0.4). Both results became more pronounced at 12 mo. There was some evidence to suggest that those patients with initial NPI >/= 15 benefited on neuropsychiatric symptoms from continuing treatment.

CONCLUSIONS

For most patients with AD, withdrawal of neuroleptics had no overall detrimental effect on functional and cognitive status. Neuroleptics may have some value in the maintenance treatment of more severe neuropsychiatric symptoms, but this benefit must be weighed against the side effects of therapy.

TRIAL REGISTRATION

Cochrane Central Registry of Controlled Trials/National Research Register (#ISRCTN33368770).

Haemophilus influenzae type b vaccine failure in children is associated with inadequate production of high-quality antibody

BACKGROUND

Despite the excellent immunogenicity of Haemophilus influenzae type b (Hib) conjugate vaccines, breakthrough cases of Hib disease still affect a small proportion of vaccinated children in the United Kingdom. We performed a retrospective study to compare the avidity of antibody directed against the Hib polysaccharide capsule (PRP) in children who experienced Hib vaccine failure in the United Kingdom among 3 historical cohorts and with age-matched healthy control subjects.

METHODS

Serum samples from vaccinated children with invasive Hib disease were collected beginning in 1992 as part of enhanced surveillance for Hib disease following vaccine introduction. A total of 251 children who experienced Hib vaccine failure were identified from 3 historical cohorts (1992-1995, 1996-1999, and 2000-2003). The anti-PRP antibody concentration and avidity from healthy age-matched control subjects was obtained for the 3 contemporary time points (1995, 1999, and 2002). Serum anti-PRP antibody concentration was measured in each of the samples using a standard Hib ELISA, and antibody avidity was determined using thiocyanate elution.

RESULTS

Within the first 60 days after disease onset, there was no change in the anti-PRP antibody avidity, and there was no statistically significant difference in the geometric mean Hib antibody avidity over the 3 study periods. However, the children who experienced Hib vaccine failure had significantly lower Hib antibody avidity than did healthy control subjects, despite a marked antibody response following infection.

CONCLUSIONS

Children who experience Hib disease despite vaccination appear to have a defect in immunological priming, leading to a qualitative difference in Hib-specific memory B cells. Low anti-PRP antibody avidity decreases the functional activity of anti-PRP antibody in the sera of these children experiencing vaccine failure, leading to disease susceptibility.

Immunogenicity of a tetravalent meningococcal glycoconjugate vaccine in infants: a randomized controlled trial

CONTEXT

Immunization with a meningococcal tetravalent (serogroup ACWY) glycoconjugate vaccine is recommended for all US adolescents. However, the currently licensed vaccine is poorly immunogenic in infancy, when the highest rates of disease are observed.

OBJECTIVE

To determine the immunogenicity of a novel tetravalent CRM(197)-conjugated meningococcal vaccine (MenACWY) in infants.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, open-label, controlled study of 225 UK and 196 Canadian 2-month-olds from August 2004 to September 2006.

INTERVENTION

UK infants received a primary course of MenACWY (at 2, 3, and 4 months or 2 and 4 months) or Neisseria meningitidis serogroup C monovalent meningococcal glycoconjugate vaccine (MenC) (at 2 and 4 months). All received MenACWY at 12 months. Canadian infants received MenACWY at 2, 4, and 6 months or 2 and 4 months; at 12 months they received MenACWY, a plain tetravalent polysaccharide vaccine, or no vaccine.

MAIN OUTCOME MEASURE

Percentage of infants with a human complement serum bactericidal activity (hSBA) titer >or=1:4 after a primary course of MenACWY and after a 12-month booster. Safety and reactogenicity of MenACWY were also assessed.

RESULTS

According to the prespecified per-protocol analysis, the percentages (95% CIs) of MenACWY 2-, 3-, and 4-month recipients with hSBA titers >or=1:4 after primary immunization were serogroup A, 93% (84%-98%); C, 96% (89%-99%); W-135, 97% (90%-100%); and Y, 94% (86%-98%). With a post hoc intention-to-treat analysis with imputed values for missing data, these values were unchanged for serogroups C and Y; for serogroup A, values were 92% (84%-97%), and for W-135, 97% (91%-99%). For the per-protocol analysis of MenACWY 2-, 4-, and 6-month recipients, the percentages (95% CIs) of responders were A, 81% (71%-89%); C, 98% (92%-100%); W-135, 99% (93%-100%); and Y, 98% (92%-100%). With the imputed value analysis, these values were A, 83% (74%-89%); C, 98% (93%-99%); W-135, 99% (94%-100%); and Y, 98% (92%-99%). At least 84% of MenACWY 2- and 4-month recipients achieved hSBA titers >or=1:4 for serogroups C, W-135, and Y after primary immunization, as did at least 60% for serogroup A (per-protocol and imputation analysis). At least 95% of primary and booster MenACWY recipients achieved hSBA titers >or=1:4 for serogroups C, W-135, and Y at 13 months, as did at least 84% for serogroup A (per-protocol and imputation analysis). During the primary immunization course, postimmunization pain on leg movement was observed in 2% of UK MenACWY 2- and 4-month recipients and 4% of MenC 2- and 4-month recipients; a temperature of 38 degrees C or greater was observed in 4% and 2% in these groups, respectively.

CONCLUSION

MenACWY is well tolerated and immunogenic in infancy. Trial Registration clinicaltrials.gov Identifier: NCT00262002.

Evaluation of the Ages and Stages Questionnaires in identifying children with neurosensory disability in the Magpie Trial follow-up study

AIM

To evaluate performance of the Ages and Stages Questionnaires (full ASQ), and a shortened version (short ASQ), in detecting children with severe neurosensory disability in the Magpie Trial follow-up study.

METHODS

All children, born to women in the Magpie Trial and selected for follow-up, with a completed full 30 items and/or short 9-items ASQ were included in this analysis. Sensitivity and specificity, corrected for verification bias, were computed to assess detection ability.

RESULTS

Of the 2046 children who completed a full ASQ, 406 (19.8%) failed the assessment, 54 of whom had confirmed neurosensory disability. Adjusted sensitivity and specificity (95% confidence intervals) were 87.4% (62.9-96.6%), and 82.3% (80.5-83.9%), respectively. Two of the five domains in the full ASQ (Fine Motor and Problem Solving) contributed little to detection ability. Sensitivity and specificity for the short ASQ were 69.2% and 95.7%, respectively.

CONCLUSIONS

Sensitivity of the full ASQ for severe neurosensory disability is generally good, and does not appear to be much reduced by restricting questions to three out of the five domains. The short ASQ reported here reduced performance, although this might be improved by a different choice of questions or scoring system.

Uptake and acceptability of influenza vaccination in day nursery children

Preschoolers play an important role in the transmission of influenza, and suffer significant morbidity. Paediatric vaccination could prevent serious outcomes and offer broader societal benefits. This study explored parental views on influenza and paediatric vaccination and determined the uptake of a nursery-based vaccination programme for infants aged 6-23 months. Children were offered two doses of inactivated vaccine in 2004/05, and a single dose at the start of the 2005/06 season. An uptake rate of 11% (60/535) was achieved with 83% (50/60) of participants completing the programme. Semi-structured interviews were conducted with 10 parents. Thematic analysis of the data informed the development of a questionnaire. This was distributed to 650 parents, with children aged 6-30 months attending one of the 18 supporting nurseries. A response rate of 13% (83/650) was achieved. The low uptake rate achieved in the programme and findings from the interviews/questionnaire suggest parents were not convinced about the seriousness of paediatric influenza. Indeed, over two-thirds (55/81) questioned the necessity for an annual vaccination. Parents found it difficult to differentiate influenza from other respiratory illnesses, and expressed concerns about the need for annual injections and vaccine safety. Paediatric vaccination to increase herd immunity was held in balance with the notion that children should only be vaccinated if they are the main beneficiaries. Parental education on the burden of childhood influenza, on the direct benefits of influenza vaccination, and on indirect benefits to society is a necessity for a successful paediatric vaccination programme.

A systematic comparison of software dedicated to meta-analysis of causal studies

Background

Our objective was to systematically assess the differences in features, results, and usability of currently available meta-analysis programs.

Methods

Systematic review of software. We did an extensive search on the internet (Google, Yahoo, Altavista, and MSN) for specialized meta-analysis software. We included six programs in our review: Comprehensive Meta-analysis (CMA), MetAnalysis, MetaWin, MIX, RevMan, and WEasyMA. Two investigators compared the features of the software and their results. Thirty independent researchers evaluated the programs on their usability while analyzing one data set.

Results

The programs differed substantially in features, ease-of-use, and price. Although most results from the programs were identical, we did find some minor numerical inconsistencies. CMA and MIX scored highest on usability and these programs also have the most complete set of analytical features.

Conclusion

In consideration of differences in numerical results, we believe the user community would benefit from openly available and systematically updated information about the procedures and results of each program's validation. The most suitable program for a meta-analysis will depend on the user's needs and preferences and this report provides an overview that should be helpful in making a substantiated choice.

Assessing disease burden of respiratory disorders in Hong Kong children with hospital discharge data and linked laboratory data

OBJECTIVES

To describe the pattern of respiratory disorders in the Hong Kong paediatric population admitted to government hospitals, and to assess the reliability of the diagnoses by linkage with laboratory data.

METHODS

Discharge diagnoses for all admissions are recorded in a central computerised database, the Clinical Management System. These data were analysed for the inclusive period July 1997 to June 1999. Virology laboratory results from a single hospital were linked to the Clinical Management System diagnostic codes to examine discrepancies in coding specific viral aetiologies.

RESULTS

A primary diagnosis of a respiratory disorder was noted in 37.5% (upper respiratory 30.1%, tonsillitis/pharyngitis 10.5%, croup/laryngitis 2.3%, acute otitis media 2.7%, bronchitis/chest infection 2.6%, bronchiolitis 10.2%, pneumonia 20.9%, influenza 4%, asthma and allergic rhinitis 16.5%), and a primary or secondary diagnosis in 42.5% of children younger than 15 years. The incidence rates of respiratory illness coded as bronchiolitis and influenza were respectively estimated to be 887-979 and 222-381 per 100,000 children under 5 years and 3551-3949 and 415-528 per 100,000 children under the age of 1 year. The percentage of respiratory-associated admissions varied significantly by hospital and detailed analysis of data at one hospital highlighted important discrepancies between discharge diagnosis and laboratory results.

CONCLUSIONS

These passive surveillance data provide general estimates of the disease burden for respiratory disorders in Hong Kong children. Active surveillance studies are required to provide more accurate estimates of the disease burden. Consideration should be given to enhance the Clinical Management System by routinely linking all laboratory data with discharge diagnosis information, by establishing sentinel surveillance hospitals and by assessing new strategies to standardise coding.

Development and validation of MIX: comprehensive free software for meta-analysis of causal research data

BACKGROUND

Meta-analysis has become a well-known method for synthesis of quantitative data from previously conducted research in applied health sciences. So far, meta-analysis has been particularly useful in evaluating and comparing therapies and in assessing causes of disease. Consequently, the number of software packages that can perform meta-analysis has increased over the years. Unfortunately, it can take a substantial amount of time to get acquainted with some of these programs and most contain little or no interactive educational material. We set out to create and validate an easy-to-use and comprehensive meta-analysis package that would be simple enough programming-wise to remain available as a free download. We specifically aimed at students and researchers who are new to meta-analysis, with important parts of the development oriented towards creating internal interactive tutoring tools and designing features that would facilitate usage of the software as a companion to existing books on meta-analysis.

RESULTS

We took an unconventional approach and created a program that uses Excel as a calculation and programming platform. The main programming language was Visual Basic, as implemented in Visual Basic 6 and Visual Basic for Applications in Excel 2000 and higher. The development took approximately two years and resulted in the 'MIX' program, which can be downloaded from the program's website free of charge. Next, we set out to validate the MIX output with two major software packages as reference standards, namely STATA (metan, metabias, and metatrim) and Comprehensive Meta-Analysis Version 2. Eight meta-analyses that had been published in major journals were used as data sources. All numerical and graphical results from analyses with MIX were identical to their counterparts in STATA and CMA. The MIX program distinguishes itself from most other programs by the extensive graphical output, the click-and-go (Excel) interface, and the educational features.

CONCLUSION

The MIX program is a valid tool for performing meta-analysis and may be particularly useful in educational environments. It can be downloaded free of charge via http://www.mix-for-meta-analysis.info or http://sourceforge.net/projects/meta-analysis.