Paediatric meningitis in the conjugate vaccine era and a novel clinical decision model to predict bacterial aetiology.

OBJECTIVES: The aims of this study were to assess aetiology and clinical characteristics in childhood meningitis, and develop clinical decision rules to distinguish bacterial meningitis from other similar clinical syndromes. METHODS: Children aged <16 years hospitalised with suspected meningitis/encephalitis were included, and prospectively recruited at 31 UK hospitals. Meningitis was defined as identification of bacteria/viruses from cerebrospinal fluid (CSF) and/or a raised CSF white blood cell count. New clinical decision rules were developed to distinguish bacterial from viral meningitis and those of alternative aetiology. RESULTS: The cohort included 3002 children (median age 2·4 months); 1101/3002 (36·7%) had meningitis, including 180 bacterial, 423 viral and 280 with no pathogen identified. Enterovirus was the most common pathogen in those aged <6 months and 10-16 years, with Neisseria meningitidis and/or Streptococcus pneumoniae commonest at age 6 months to 9 years. The Bacterial Meningitis Score had a negative predictive value of 95·3%. We developed two clinical decision rules, that could be used either before (sensitivity 82%, specificity 71%) or after lumbar puncture (sensitivity 84%, specificity 93%), to determine risk of bacterial meningitis. CONCLUSIONS: Bacterial meningitis comprised 6% of children with suspected meningitis/encephalitis. Our clinical decision rules provide potential novel approaches to assist with identifying children with bacterial meningitis. FUNDING: This study was funded by the Meningitis Research Foundation, Pfizer and the NIHR Programme Grants for Applied Research.

The role of hypnotherapy in evidence-based clinical practice.

The purpose of this review was to discuss the place of hypnotherapy in a modern medical world dominated by so-called evidence-based clinical practice. Hypnosis is an easily learned technique that is a valuable adjuvant to many medical, dental and psychological interventions.

Increased expression of GDF-15 may mediate ICU-acquired weakness by down-regulating muscle microRNAs.

RATIONALE: The molecular mechanisms underlying the muscle atrophy of intensive care unit-acquired weakness (ICUAW) are poorly understood. We hypothesised that increased circulating and muscle growth and differentiation factor-15 (GDF-15) causes atrophy in ICUAW by changing expression of key microRNAs. OBJECTIVES: To investigate GDF-15 and microRNA expression in patients with ICUAW and to elucidate possible mechanisms by which they cause muscle atrophy in vivo and in vitro. METHODS: In an observational study, 20 patients with ICUAW and seven elective surgical patients (controls) underwent rectus femoris muscle biopsy and blood sampling. mRNA and microRNA expression of target genes were examined in muscle specimens and GDF-15 protein concentration quantified in plasma. The effects of GDF-15 on C2C12 myotubes in vitro were examined. MEASUREMENTS AND MAIN RESULTS: Compared with controls, GDF-15 protein was elevated in plasma (median 7239 vs 2454 pg/mL, p=0.001) and GDF-15 mRNA in the muscle (median twofold increase p=0.006) of patients with ICUAW. The expression of microRNAs involved in muscle homeostasis was significantly lower in the muscle of patients with ICUAW. GDF-15 treatment of C2C12 myotubes significantly elevated expression of muscle atrophy-related genes and down-regulated the expression of muscle microRNAs. miR-181a suppressed transforming growth factor-ß (TGF-ß) responses in C2C12 cells, suggesting increased sensitivity to TGF-ß in ICUAW muscle. Consistent with this suggestion, nuclear phospho-small mothers against decapentaplegic (SMAD) 2/3 was increased in ICUAW muscle. CONCLUSIONS: GDF-15 may increase sensitivity to TGF-ß signalling by suppressing the expression of muscle microRNAs, thereby promoting muscle atrophy in ICUAW. This study identifies both GDF-15 and associated microRNA as potential therapeutic targets.

Post-acute serum eosinophil and neutrophil-associated cytokine/chemokine profile can distinguish between patients with neuromyelitis optica and multiple sclerosis; and identifies potential pathophysiological mechanisms - a pilot study.

Neuromelitis optica (NMO) is an inflammatory, demyelinating disease of the central nervous system. It is distinguished from multiple sclerosis (MS) by clinical and radiological features and the presence of aquaporin 4 antibodies in approximately 70%. Despite the discovery of these antibodies and the evidence of neutrophils and eosinophils in the CNS parenchyma, the immunopathogenesis of NMO remains poorly understood. Previous studies attempting to assess the role cytokines and chemokines in NMO have primarily been conducted in acute cerebrospinal fluid from East Asian cohorts, have assessed small numbers of mediators in isolation and have not accounted for important confounding factors including antibody status and disease severity. Therefore we conducted a study of a more extensive range of cytokines and associated mediators in post-acute serum from a UK cohort using unsupervised and multivariate analytical techniques to assess the relative concentration of mediators in concert. Our study of 29 patients (aquaporin 4 antibody positive NMO n=19, MS n=10), matched where possible, including for disease severity, has identified and confirmed some key cytokine/chemokine markers in NMO distinct from MS. Our findings shed further light on the importance of specific inflammatory mediators with predominant function in the differentiation, chemotaxis and activity of neutrophils and eosinophils, particularly CCL4, CCL11, granulocyte-colony stimulating factor and myeloperoxidase, and these may represent potential immunomodulatory targets.

Encephalitis caused by flaviviruses.

The genus Flavivirus, family Flaviviridae, contains some of the most important arboviral pathogens of man. The genus includes several aetiological agents of encephalitis, the most significant being Japanese encephalitis virus, West Nile virus and tick-borne encephalitis virus. In each case, the majority of exposed individuals will not develop disease, but a minority will develop a severe illness with a significant chance of permanent neurological damage or death. The factors that determine this are numerous, involving complex interactions between virus and host and are still being actively uncovered. In many cases it appears that the immune response, while crucial to containing the virus and limiting spread to the brain, is also responsible for causing neurological damage. Innate responses can limit viral replication but may also be responsible for generating pathological levels of inflammation. Neutralizing antibody responses are protective but take time to develop. The role of T cells is less clear, and may be either protective or pathogenic. This review summarizes recent developments in the understanding of the pathogenesis of encephalitis caused by flaviviruses.

Pro-oxidant iron in exhaled breath condensate: a potential excretory mechanism.

AIMS: Pro-oxidant iron provides a potential measure of iron-catalysed oxidative stress in biological fluids. This study aimed, to investigate if the Bleomycin technique for measurement of pro-oxidant iron in biological fluids could be utilised for determinations in exhaled breath condensate (EBC). Secondly, to measure levels of pro-oxidant iron in EBC from asthmatics after exposure to polluting city environments. METHODS: Retrospective analysis of samples of EBC and bronchoalveolar lavage fluid (BALF). Pro-oxidant iron levels were determined by the Bleomycin method. Transferrin levels were determined by radial diffusion immunoassay and lactoferrin by ELISA. SUBJECTS: Patients undergoing surgery necessitating cardiopulmonary bypass, normal healthy controls, "healthy" smokers, and asthmatics (mild and moderate). RESULTS: Pro-oxidant iron was significantly decreased (p<0.05) post cardiac surgery in both EBC and BALF. In smokers levels of pro-oxidant iron in EBC were significantly (p<0.05) increased verses healthy controls. In asthmatics with more severe disease, there were significant increases in EBC pro-oxidant iron content post exposure to city environments (p<0.001), with levels most elevated after exposure to the most polluted setting. CONCLUSION: Similar patterns in the levels of pro-oxidant iron detectable in EBC and paired BALF from patients undergoing cardiopulmonary bypass (pre and post surgery) suggest a potential for EBC determinations. Significantly elevated levels in EBC from smokers relative to control subjects provide further support for this technique. In asthma disease severity and environmental exposure influenced levels of pro-oxidant iron measured in EBC indicating a potential for enhanced iron-catalysed oxidative stress.

Selection of direct transesterification as the preferred method for assay of fatty acid content of microalgae.

Assays for total lipid content in microalgae are usually based on the Folch or the Bligh and Dyer methods of solvent extraction followed by quantification either gravimetrically or by chromatography. Direct transesterification (DT) is a method of converting saponifiable lipids in situ directly to fatty acid methyl esters which can be quantified by gas chromatography (GC). This eliminates the extraction step and results in a rapid, one-step procedure applicable to small samples. This study compared the effectiveness of DT in quantifying the total fatty acid content in three species of microalgae to extraction using the Folch, the Bligh and Dyer and the Smedes and Askland methods, followed by transesterification and GC. The use of two catalysts in sequence, as well as the effect of reaction water content on the efficiency of DT were investigated. The Folch method was the most effective of the extraction methods tested, but comparison with DT illustrated that all extraction methods were incomplete. Higher levels of fatty acid in the cells were obtained with DT in comparison with the extraction-transesterification methods. A combination of acidic and basic transesterification catalysts was more effective than each individually when the sample contained water. The two-catalyst reaction was insensitive to water up to 10% of total reaction volume. DT proved a convenient and more accurate method than the extraction techniques for quantifying total fatty acid content in microalgae.

Extracorporeal carbon dioxide removal to "protect" the lung.

The case histories are presented of three adults who had severe hypercapnic acidosis despite mechanical ventilation with what were considered to be injurious tidal volumes and airway pressures. The use of a percutaneously inserted arteriovenous extracorporeal carbon dioxide removal (AV-ECCO(2)R) device facilitated a dramatic reduction in the amount of ventilatory support required, achieving a "lung-protective" level. Two patients survived to hospital discharge. One patient died after it became apparent that her late-stage interstitial lung disease was unresponsive to immunosuppression. AV-ECCO(2)R may be a useful strategy in facilitating lung-protective ventilation.

PMX464, a thiol-reactive quinol and putative thioredoxin inhibitor, inhibits NF-kappaB-dependent proinflammatory activation of alveolar epithelial cells.

BACKGROUND AND PURPOSE: Subtle changes in the intracellular reduction-oxidation (redox) state can modulate nuclear factor-kappaB (NF-kappaB) activity. Thioredoxin-1 (Trx) is a small, ubiquitous, redox-active thiol (-SH) protein that, with thioredoxin reductase-1 (TrxR), modifies the redox status of NF-kappaB pathway components. PMX464 is a novel thiol-reactive quinol thought to inhibit the Trx/TrxR system. The aim of this work was to investigate whether PMX464 inhibited NF-kappaB-mediated proinflammatory activation of human type II alveolar epithelial cells (A549). EXPERIMENTAL APPROACH: Intercellular adhesion molecule-1 (ICAM-1), granulocyte-macrophage colony-stimulating factor (GM-CSF) and CXCL8, NF-kappaB DNA binding, nuclear translocation of NF-kappaB p65 subunit, IkappaBalpha degradation, IkappaB phosphorylation and IkappaB kinase (IKK) activity were assessed in A549 cells stimulated with IL-1beta with or without PMX464 pretreatment. Effects of PMX464 on ICAM-1 expression in human lung microvascular endothelial cells (HLMVEC) were also investigated. For comparison, selected measurements (ICAM-1 and IkappaB-alpha phospho-IkappaB-alpha) were made on A549 cells after RNA interference-mediated silencing (siRNA) of Trx. KEY RESULTS: PMX464 reduced ICAM-1, GM-CSF and CXCL8 expression in IL-1beta-stimulated A549 cells and ICAM-1 in HLMVEC. PMX464 inhibited IL-1beta-induced NF-kappaB DNA binding, nuclear translocation of NF-kappaB p65 subunit and factors involved in NF-kappaB activation; specifically, IkappaBalpha degradation, IkappaB phosphorylation and IkappaB kinase (IKK) activity in A549. By contrast, Trx siRNA did not alter ICAM-1 expression or IkappaBalpha degradation/phosphorylation in IL-1beta-stimulated A549 cells. CONCLUSION AND IMPLICATIONS: PMX464 inhibits a proinflammatory response in A549 cells targeting the NFkappaB pathway above IKK. The lack of effect with Trx siRNA suggests that PMX464 acts on thiol proteins, in addition to Trx, to elicit anti-inflammatory responses in lung epithelial cells.

Variation in the ICAM1 gene is not associated with severe malaria phenotypes.

Evidence from autopsy and in vitro binding studies suggests that adhesion of erythrocytes infected with Plasmodium falciparum to the human host intercellular adhesion molecule (ICAM)-1 receptor is important in the pathogenesis of severe malaria. Previous association studies between polymorphisms in the ICAM1 gene and susceptibility to severe malarial phenotypes have been inconclusive and often contradictory. We performed genetic association studies with 15 single nucleotide polymorphisms (SNPs) around the ICAM1 locus. All SNPs were screened in a family study of 1071 trios from The Gambia, Malawi and Kenya. Two key non-synonymous SNPs with previously reported associations, rs5491 (K56M or 'ICAM-1(Kilifi)') and rs5498 (K469E), were tested in an additional 708 Gambian trios and a case-control study of 4058 individuals. None of the polymorphisms were associated with severe malaria phenotypes. Pooled results across our studies for ICAM-1(Kilifi) were, in severe malaria, odds ratio (OR) 1.02, 95% confidence interval (CI) 0.96-1.09, P=0.54, and cerebral malaria OR 1.07, CI 0.97-1.17, P=0.17. We assess the available epidemiological, population genetic and functional evidence that links ICAM-1(Kilifi) to severe malaria susceptibility.

B-type natriuretic peptide in reversible myocardial ischaemia.

BACKGROUND: Coronary heart disease is associated with increased B-type natriuretic peptides (BNPs), and, although controversial, may cause exaggerated exercise-induced BNP secretion. We investigated BNP in relation to reversible myocardial ischaemia. MATERIALS AND METHODS: Serum N-terminal proBNP (NT-proBNP) was measured before and after an exercise electrocardiogram test (ETT) in 14 patients with and 45 patients without exercise-induced myocardial ischaemia. Statistical analysis was carried out on logarithmically transformed data. Results, however, are pre-transformed data. RESULTS: NT-proBNP increased with exercise both in ETT-positive patients (mean (SD) 71.4 (41.2) v 76.8 (44.0) ng/l; p<0.001) and ETT-negative patients (54.0 (61.2) v 60.1 (69.0) ng/l; p<0.001). Pre-exercise and post-exercise NT-proBNP were higher (p<0.05) in ETT-positive than in ETT-negative patients. Incremental NT-proBNP was similar in ETT-positive (4.7 (4.2) ng/l) and ETT-negative (6.2 (8.6) ng/l) patients. CONCLUSION: Serum NT-proBNP concentrations are higher in patients with exercise-induced myocardial ischaemia than in those without. Exercise-induced electrocardiographic myocardial ischaemia, however, is not associated with exaggerated BNP secretion.

Ultrasound guided deep cervical plexus block.

We describe a new technique for achieving a deep cervical plexus block using a portable vascular access ultrasound scanner (Site-Rite II, Bard Access Systems, Pittsburgh, PA).

Repopulation of human pulmonary epithelium by bone marrow cells: a potential means to promote repair.

After lung injury and damage to the alveolar epithelium, the underlying basement membranes become exposed. Proliferation of type II pneumocytes and their differentiation to the type I phenotype have been considered to be the mechanism by which repopulation of the alveolar epithelium occurs. A growing body of evidence has shown that tissues can be repaired by cells acquired via the circulation. For the lung, bone marrow stem cells have been shown in mice to regenerate epithelium as well as give rise to the expected mesodermal derivatives. We hypothesized that extrapulmonary cells, including those from the bone marrow, can contribute to the reepithelialization of human alveoli. To investigate this, we examined samples of peripheral lung from patients who had undergone cross-gender transplantation of lung or bone marrow. Thus, archival blocks of peripheral lung were analyzed from male patients (surgical samples, n = 8) who had received a lung transplant from a female donor and female patients (postmortem samples, n = 3) who had male bone marrow transplants. In both cases, male cells were identified in the female lungs by Y chromosome in situ hybridization. Male cells could be identified in the alveolar epithelium where, in the better preserved, transplanted lungs, it was possible to show that some had differentiated to type II pneumocytes. In addition, Y chromosomes were found to be widespread in cells of mesenchymal lineage, including macrophages and endothelial cells. Concomitant visualization of Y and X chromosomes, using fluorescence immunolabeling, yielded no evidence of cellular fusion, although the poor quality of the autopsy samples studied meant that the possibility could not be excluded. These observations suggest that, as occurs in rodents, the epithelium of the adult human lung has the capacity to renew itself, using cells recruited from extrapulmonary sources, including the bone marrow. This finding could provide new therapeutic opportunities for a range of pulmonary diseases by providing means to repair the lung and a novel route for gene therapy.

Adult spontaneous hypoglycaemia.

Spontaneous hypoglycaemia is not a diagnosis, but a manifestation of a disease process. It is important to recognize spontaneous hypoglycaemia, as treatment may be preventative or curative. It is equally important to avoid mislabelling healthy individuals as having hypoglycaemia as this may have a negative impact on the quality of life and use of scarce health-care resources.