Plasma lipid profiles discriminate bacterial from viral infection in febrile children

Fever is the most common reason that children present to Emergency Departments. Clinical signs and symptoms suggestive of bacterial infection are often non-specific, and there is no definitive test for the accurate diagnosis of infection. The 'omics' approaches to identifying biomarkers from the host-response to bacterial infection are promising. In this study, lipidomic analysis was carried out with plasma samples obtained from febrile children with confirmed bacterial infection (n = 20) and confirmed viral infection (n = 20). We show for the first time that bacterial and viral infection produces distinct profile in the host lipidome. Some species of glycerophosphoinositol, sphingomyelin, lysophosphatidylcholine and cholesterol sulfate were higher in the confirmed virus infected group, while some species of fatty acids, glycerophosphocholine, glycerophosphoserine, lactosylceramide and bilirubin were lower in the confirmed virus infected group when compared with confirmed bacterial infected group. A combination of three lipids achieved an area under the receiver operating characteristic (ROC) curve of 0.911 (95% CI 0.81 to 0.98). This pilot study demonstrates the potential of metabolic biomarkers to assist clinicians in distinguishing bacterial from viral infection in febrile children, to facilitate effective clinical management and to the limit inappropriate use of antibiotics

Silicon nanowires, carbon nanotubes, and magnetic nanocrystals: synthesis, properties, and applications

textCentral to the practical use of nanoscale materials is the controlled growth in technologically meaningful quantities. Many of the proposed applications of the nanomaterials potentially require inexpensive production of the building blocks. Solution-based synthetic approach offers controllability, high throughput, and scalability, which make the process attractive for the potential scale-up. Growth kinetics could be readily influenced by chemical interactions between the precursor and the solvent. In order to fully utilize its benefits, it is therefore pivotal to understand the decomposition chemistry of the precursors used in the reactions. Supercritical fluids were used as solvent in which high temperature reactions could take place. Silicon nanowires with diameters of 20~30 nm was synthesized in supercritical fluids with metal nanocrystals as seeds for the nanowire growth. To unravel the effect of silicon precursors, several silicon precursors were reacted and the resulting products were investigated. The scalability of the system is discussed based on the experimental data. The nanowires were characterized with various characterization tools, including high-resolution transmission electron microscopy and electron energy loss spectroscopy. The crystallographic signatures were analyzed through the transmission electron microscopic study, and fundamental electrical and optical properties were probed by electron energy loss spectroscopy. Carbon nanotubes were prepared by reacting carbon-containing chemicals in supercritical fluids with organometallic compounds that form metal seed particles in-situ. A batch reaction, in which the temperature control was relatively poor, yielded a mixture of multiwall nanotubes and amorphous carbon nanofilaments with a low selectivity of nanotubes in the product. When reaction parameters were translated into a continuous flow-through reaction, nanotube selectivity as well as the throughput of the total product significantly improved. Magnetic properties of various metal nanocrystals were also studied. Colloidal synthesis enables the growth of FePt and MnPt3 nanocrystals with size uniformity. The as-synthesized nanocrystals, however, had compositionally disordered soft-magnetic phases. To obtain hard magnetic layered phase, the nanocrystals must be annealed at high temperatures, which led to sintering of the inorganic cores. To prevent sintering, the nanocrystals were encapsulated with silica layer prior to annealing. Interparticle magnetic interactions were also explored using particles with varying silica thickness.Chemical Engineerin

Why do endocrine profiles in elite athletes differ between sports?

Background: Endocrine profiles have been measured on blood samples obtained immediately post-competition from 693 elite athletes from 15 Olympic Sports competing at National or International level; four were subsequently excluded leaving 689 for the current analysis. Methods: Body composition was measured by bioimpedance in a sub-set of 234 (146 men and 88 women) and from these data a regression model was constructed that enabled ‘estimated’ lean body mass and fat mass to be calculated on all athletes. One way ANOVA was used to assess the differences in body composition and endocrine profiles between the sports and binary logistical regression to ascertain the characteristic of a given sport compared to the others.Results: The results confirmed many suppositions such as basketball players being tall, weightlifters short and cross-country skiers light. The hormone profiles were more surprising with remarkably low testosterone and free T3 (tri-iodothyronine) in male powerlifters and high oestradiol, SHBG (sex hormone binding globulin) and prolactin in male track and field athletes. Low testosterone concentrations were seen 25.4% of male elite competitors in 12 of the 15 sports and high testosterone concentrations in 4.8% of female elite athletes in 3 of the 8 sports tested. Interpretation of the results is more difficult; some of the differences between sports are at least partially due to differences in age of the athletes but the apparent differences between sports remain significant after adjusting for age. The prevalence of ‘hyperandrogenism’ (as defined by the IAAF (International Association of Athletics Federations) and IOC (International Olympic Committee)) amongst this cohort of 231 elite female athletes was the highest so far recorded and the very high prevalence of ‘hypoandrogenism’ in elite male athletes a new finding. Conclusions: It is unclear whether the differences in hormone profiles between sports is a reason why they become elite athletes in that sport or is a consequence of the arduous processes involved. For components of body composition we know that most have a major genetic component and this may well be true for endocrine profiles.<br/

A correction to the age-adjustment of the GH-2000 score used in the detection of growth hormone misuse

Objective: The GH-2000 score has been developed as a powerful and unique technique to detect growth hormone misuse by sportsmen and women. The score depends upon the measurement of two growth hormone (GH) sensitive markers, insulin-like growth factor-I (IGF-I) and the amino-terminal pro-peptide of type III collagen (P-III-NP). It has been previously suggested that the score shows a positive age effect in male athletes, which could potentially place older male athletes at a disadvantage. The purpose of this note is to investigate the performance of a previously suggested correction term in two new and larger data sets. Results: The GH-2000 score was calculated for 7307 samples obtained from 15 accredited WADA laboratories in 2017 and 3916 samples measured at Drug Control Centre, King's College London, UK between 2013 and 2017. The GH-2000 scores were investigated for positive age effects using standard regression modelling. As previously, all analyses confirmed a positive age effect. Applying the earlier suggested correction term of 0.032 x age showed a significant over-correction leading to a negative association of the GH-2000 score with age. We now suggest a smaller age correction of 0.020 x age which corresponds to the smallest effect found in the earlier studies

The development of decision limits for the implementation of the GH-2000 detection methodology using current commercial insulin-like growth factor-I and amino-terminal pro-peptide of type III collagen assays

Background: The GH-2000 project developed a method for detecting GH misuse based on the measurement ofinsulin-like growth factor-I (IGF-I) and the amino-terminal pro-peptide of type III collagen (P-III-NP). The objectiveof this study was to develop decision limits for the GH-2000 score to detect GH misuse in elite athletesusing two currently available commercial assays for each analyte.Study design: Subjects: 404 male (mean age 23.9 yrs, range 12–37 yrs) and 94 female elite athletes (mean age24.5 yrs, range 18–34 yrs) participated. Blood samples were collected according to World Anti-Doping Agency(WADA) guidelines at various sporting events including 238 samples collected as part of the UK Anti-Doping Testing Programme.Laboratory analysis: IGF-I was measured by Siemens Immulite IGF-I assay and Immunotech A15729 IGF-IIRMA. P-III-NP was measured by RIA-gnost P-III-P and the UniQ™ PIIINP RIA.Statistical analysis: The GH-2000 score decision limits were developed through the analysis of the elite athletesamples.Results: For males and females separately, the distributions of GH-2000 scores were consistent with Normaldistributions. Using a specificity of 99.99% new decision limits were determined which included an allowancefor uncertainty associated with calculations based on a finite sample size. One outlier was identified with resultsincompatible with normal physiology and tested positive with the current isoform GH test.Conclusions: We have developed decision limits using currently available commercial assays to measure IGF-Iand P-III-NP in elite athletes. This should allow the introduction of a test for GH misuse based on the measurement of these GH sensitive biomarkers