David W. Johnson

Bio: David W. Johnson is an academic researcher from University of Queensland. The author has contributed to research in topics: Peritoneal dialysis & Kidney disease. The author has an hindex of 160, co-authored 2714 publications receiving 140778 citations. Previous affiliations of David W. Johnson include Minnesota Department of Transportation & Open University.

Rapid viral diagnosis for acute febrile respiratory illness in children in the Emergency Department

Abstract: Background Pediatric acute respiratory infections (ARIs) represent a significant burden on pediatric Emergency Departments (EDs) and families. Most of these illnesses are due to viruses. However, investigations (radiography, blood, and urine testing) to rule out bacterial infections and antibiotics are often ordered because of diagnostic uncertainties. This results in prolonged ED visits and unnecessary antibiotic use. The risk of concurrent bacterial infection has been reported to be negligible in children over three months of age with a confirmed viral infection. Rapid viral testing in the ED may alleviate the need for precautionary testing and antibiotic use. Objectives To determine if the use of a rapid viral detection test for children with an acute respiratory infection (ARI) in Emergency Departments (EDs) changes patient management and resource use in the ED, compared to not using a rapid viral detection test. We hypothesized that rapid viral testing reduces antibiotic use in the ED as well as reduces the rate of ancillary testing and length of ED visits. Search methods We searched CENTRAL (2014, Issue 6), MEDLINE (1950 to July week 1, 2014), MEDLINE In-Process & Other Non-Indexed Citations (15 July 2014), EMBASE.com (1988 to July 2014), HealthStar (1966 to 2009), BIOSIS Previews (1969 to July 2014), CAB Abstracts (1973 to July 2014), CBCA Reference (1970 to 2007) and ProQuest Dissertations and Theses (1861 to 2009). Selection criteria Randomized controlled trials (RCTs) of rapid viral testing for children with ARIs in the ED. Data collection and analysis Two review authors used the inclusion criteria to select trials, evaluate their quality, and extract data. We obtained missing data from trial authors. We expressed differences in rate of investigations and antibiotic use as risk ratios (RRs), and expressed difference in ED length of visits as mean differences (MDs), with 95% confidence intervals (CIs). Main results No new trials were identified in this 2014 update. We included four trials (three RCTs and one quazi-RCT), with 759 children in the rapid viral testing group and 829 in the control group. Three out of the four studies were comparable in terms of young age of participants, with one study increasing the age of inclusion up to five years of age. All studies included either fever or respiratory symptoms as inclusion criteria (two required both, one required fever or respiratory symptoms, and one required only fever). All studies were comparable in terms of exclusion criteria, intervention, and outcome data. In terms of risk of bias, one study failed to utilize a random sequence generator, one study did not comment on completeness of outcome data, and only one of four studies included allocation concealment as part of the study design. None of the studies definitively blinded participants. Rapid viral testing resulted in a trend toward decreased antibiotic use in the ED, but this was not statistically significant. We found lower rates of chest radiography (RR 0.77, 95% CI 0.65 to 0.91) in the rapid viral testing group, but no effect on length of ED visits, or blood or urine testing in the ED. No study made mention of any adverse effects related to viral testing. Authors' conclusions There is insufficient evidence to support routine rapid viral testing to reduce antibiotic use in pediatric EDs. Rapid viral testing may or may not reduce rates of antibiotic use, and other investigations (urine and blood testing); these studies do not provide enough power to resolve this question. However, rapid viral testing does reduce the rate of chest X-rays in the ED. An adequately powered trial with antibiotic use as an outcome is needed.

Systematic review: the burden of disruptive gastro-oesophageal reflux disease on health-related quality of life

Abstract: Summary Background About one-third of patients with gastro-oesophageal reflux disease (GERD) have frequent and/or severe reflux symptoms (‘disruptive GERD’). The relative burden of disruptive GERD on health-related quality of life (HRQL) has not been systematically investigated. Aim To assess the burden of disruptive vs. nondisruptive GERD on HRQL. Methods Systematic searches were conducted in PubMed and Embase. To be included, studies had to have used validated questionnaires to assess HRQL. Results Nineteen studies were included. Data on the comparative burden of frequent (ranging from daily to ≥weekly) and severe reflux symptoms were provided in eight and 13 studies respectively; six reported on the additional burden of nocturnal symptoms. Compared with individuals with nondisruptive GERD, those with disruptive GERD had 2.4-times and 1.5-times higher mean rates of absenteeism and presenteeism respectively (five studies), 1.5-times lower sleep quality scores (three studies), 1.1-times lower mean summary scores for physical and mental health (five studies) and 1.3-times lower mean scores for psychological and general well-being (four studies). Increasing symptom frequency and severity both increased the burden of disease to a similar extent. The presence of nocturnal symptoms in addition to daytime symptoms led to worsening of physical health, but their effect on mental health and work productivity was less clear. Conclusions Disruptive GERD is associated with a high burden of disease compared with occasional or mild reflux symptoms. Disease management needs to vary across the GERD spectrum and should be tailored to patients' requirements for optimal therapeutic outcomes.

Metabolic syndrome in severe chronic kidney disease: Prevalence, predictors, prognostic significance and effects of risk factor modification

Abstract: Background: Metabolic syndrome (MS) is a significant risk factor for cardiovascular disease, mortality and chronic kidney disease (CKD) in the general population. However, the prevalence, predictors, prognostic value and treatment of MS in the CKD population have not been rigorously studied.

Occupational exposure to aerosolized brevetoxins during Florida red tide events: effects on a healthy worker population

Abstract: Karenia brevis (formerly Gymnodinium breve) is a marine dinoflagellate responsible for red tides that form in the Gulf of Mexico. K. brevis produces brevetoxins, the potent toxins that cause neurotoxic shellfish poisoning. There is also limited information describing human health effects from environmental exposures to brevetoxins. Our objective was to examine the impact of inhaling aerosolized brevetoxins during red tide events on self-reported symptoms and pulmonary function. We recruited a group of 28 healthy lifeguards who are occupationally exposed to red tide toxins during their daily work-related activities. They performed spirometry tests and reported symptoms before and after their 8-hr shifts during a time when there was no red tide (unexposed period) and again when there was a red tide (exposed period). We also examined how mild exercise affected the reported symptoms and spirometry tests during unexposed and exposed periods with a subgroup of the same lifeguards. Environmental sampling (K. brevis cell concentrations in seawater and brevetoxin concentrations in seawater and air) was used to confirm unexposed/exposed status. Compared with unexposed periods, the group of lifeguards reported more upper respiratory symptoms during the exposed periods. We did not observe any impact of exposure to aerosolized brevetoxins, with or without mild exercise, on pulmonary function.

Initial sequencing and analysis of the human genome.

Abstract: The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

The social identity theory of intergroup behavior

Abstract: This chapter presents an outline of a theory of intergroup conflict and some preliminary data relating to the theory. Much of the work on the social psychology of intergroup relations has focused on patterns of individual prejudices and discrimination and on the motivational sequences of interpersonal interaction. The intensity of explicit intergroup conflicts of interests is closely related in human cultures to the degree of opprobrium attached to the notion of "renegade" or "traitor." The basic and highly reliable finding is that the trivial, ad hoc intergroup categorization leads to in-group favoritism and discrimination against the out-group. Many orthodox definitions of "social groups" are unduly restrictive when applied to the context of intergroup relations. The equation of social competition and intergroup conflict rests on the assumptions concerning an "ideal type" of social stratification in which the salient dimensions of intergroup differentiation are those involving scarce resources.