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.

Combined and alternating paracetamol and ibuprofen therapy for febrile children

Abstract: Background Health professionals frequently recommend fever treatment regimens for children that either combine paracetamol and ibuprofen or alternate them. However, there is uncertainty about whether these regimens are better than the use of single agents, and about the adverse effect profile of combination regimens. Objectives To assess the effects and side effects of combining paracetamol and ibuprofen, or alternating them on consecutive treatments, compared with monotherapy for treating fever in children. Search methods In September 2013, we searched Cochrane Infectious Diseases Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; LILACS; and International Pharmaceutical Abstracts (2009-2011). Selection criteria We included randomized controlled trials comparing alternating or combined paracetamol and ibuprofen regimens with monotherapy in children with fever. Data collection and analysis One review author and two assistants independently screened the searches and applied inclusion criteria. Two authors assessed risk of bias and graded the evidence independently. We conducted separate analyses for different comparison groups (combined therapy versus monotherapy, alternating therapy versus monotherapy, combined therapy versus alternating therapy). Main results Six studies, enrolling 915 participants, are included. Compared to giving a single antipyretic alone, giving combined paracetamol and ibuprofen to febrile children can result in a lower mean temperature at one hour after treatment (MD -0.27 °Celsius, 95% CI -0.45 to -0.08, two trials, 163 participants, moderate quality evidence). If no further antipyretics are given, combined treatment probably also results in a lower mean temperature at four hours (MD -0.70 °Celsius, 95% CI -1.05 to -0.35, two trials, 196 participants, moderate quality evidence), and in fewer children remaining or becoming febrile for at least four hours after treatment (RR 0.08, 95% CI 0.02 to 0.42, two trials, 196 participants, moderate quality evidence). Only one trial assessed a measure of child discomfort (fever associated symptoms at 24 hours and 48 hours), but did not find a significant difference in this measure between the treatment regimens (one trial, 156 participants, evidence quality not graded). In practice, caregivers are often advised to initially give a single agent (paracetamol or ibuprofen), and then give a further dose of the alternative if the child's fever fails to resolve or recurs. Giving alternating treatment in this way may result in a lower mean temperature at one hour after the second dose (MD -0.60 °Celsius, 95% CI -0.94 to -0.26, two trials, 78 participants, low quality evidence), and may also result in fewer children remaining or becoming febrile for up to three hours after it is given (RR 0.25, 95% CI 0.11 to 0.55, two trials, 109 participants, low quality evidence). One trial assessed child discomfort (mean pain scores at 24, 48 and 72 hours), finding that these mean scores were lower, with alternating therapy, despite fewer doses of antipyretic being given overall (one trial, 480 participants, low quality evidence) Only one small trial compared alternating therapy with combined therapy. No statistically significant differences were seen in mean temperature, or the number of febrile children at one, four or six hours (one trial, 40 participants, very low quality evidence). There were no serious adverse events in the trials that were directly attributed to the medications used. Authors' conclusions There is some evidence that both alternating and combined antipyretic therapy may be more effective at reducing temperatures than monotherapy alone. However, the evidence for improvements in measures of child discomfort remains inconclusive. There is insufficient evidence to know which of combined or alternating therapy might be more beneficial.Future research needs to measure child discomfort using standardized tools, and assess the safety of combined and alternating antipyretic therapy.

Hearing Function and Chronic Renal Failure

Abstract: In order to evaluate the degree and type of hearing loss in patients with chronic renal failure, 61 patients undergoing chronic hemodialysis were examined. Hearing threshold levels, adjusted for age and sex, demonstrated a significant high frequency deficit, which in some patients was noted early in the course of hemodialysis. Fluctuations in hearing were noted over single dialysis events but were transient and apparently independent of corresponding changes in Na, K, Ca, BUN, creatinine, glucose, mean blood pressure, and weight. Preliminary attempts to evaluate hyperlipidemia as a possible cause of hearing loss did not reveal any hearing deficit or gain as related to triglyceride or cholesterol levels. The data suggested other possible causes of observed auditory loss.

The impact of extended-hours home hemodialysis and buttonhole cannulation technique on hospitalization rates for septic events related to dialysis access

Abstract: Few studies adequately document adverse events in patients receiving long, slow, and overnight hemodialysis (NHD). Concerns about high rates of dialysis access complications have been raised. This is an observational cohort study comparing hospital admission rates for vascular access complications between alternate nightly NHD (n=63) and conventional hemodialysis (n=172) patients established on chronic hemodialysis for at least 3 months. Overall, hospital admission rates and hospital admission rates for cardiac and all infective events are also reported. The NHD cohort was younger and less likely to be female, diabetic, or have ischemic heart disease than the conventional hemodialysis cohort. When NHD and buttonhole cannulation technique were used simultaneously, there was a demonstrated increased risk of septic dialysis access events: incidence rate ratio 3.0 (95% confidence interval 1.04-8.66) (P=0.04). The majority of blood culture isolates in NHD patients were gram-positive organisms, particularly Staphylococcus aureus. Alternate nightly NHD did not significantly change total hospital admissions or hospital admissions for indications other than dialysis access complications, compared with conventional hemodialysis. Our data suggest that buttonhole cannulation technique should be used with caution in patients performing extended-hours hemodialysis as this combination appears to increase the risk of septic access complications. Randomized-controlled trials are needed to confirm these findings.

Study of the interaction of nitric oxide with Cu(100) and Cu(111) surfaces using low energy electron diffraction and electron spectroscopy

Abstract: The adsorption of nitric oxide on Cu(100) and Cu(111) surfaces has been studied by combining X-ray and u.v. photoelectron spectroscopy with low energy electron diffraction. At 80 K two molecular states, characterised by N(1s) values of 399.5 and 401 eV, have been assigned to “bent” and “linear” configurations, respectively. The bent form dissociates slowly at 80 K while the linear species desorbs above ≈ 170 K. Assignments of the “bent” and “linear” forms were facilitated by recourse to the known sterochemistry of metal nitrosyl complexes where a correlation between formal charge on the ligand and sterochemistry has been established. Furthermore the results are compared with the adsorption of NO on both clean nickel and nickel whose surface reactivity has been controlled by pre-exposure to oxygen.The N-adatoms arising from dissociation at 80 K are mobile and highly reactive forming N2O which remains on the surface at this temperature. There is no evidence for dinitrogen desorption. The N2O was characterised by both its X-ray and u.v. photoelectron spectra. Cu(100) and Cu(111) behave similarly, Cu(111) being less active than Cu(100) in dissociation. At 80 K with Cu(100) there is evidence from LEED for the formation of an ordered (√2 ×√2)R45° structure superimposed on an increase in the background intensity of the scattered electrons. On warming the adlayer to 290 K well ordered (√2 ×√2)R45°–O structures are present. No ordered structures were observed with Cu(111) at either 80 or 290 K and this is compatible with previous studies of chemisorbed oxygen on Cu(111). At 290 K NO chemisorbed dissociatively on Cu(100) and Cu(111) both fragments being retained at the surface. With Cu(100) the symmetry of the adlayer conformed to a (√2 ×√2)R45° structure.From a curve fitting analysis of the O(1s) data for the adlayer formed on Cu(100) concentrations of the individual surface species O(a), NO(a) and N2O(a) present at 80 K and on thermal activation to 110, 133 and 290 K were calculated.

Relationships Among Cooperative Learning Experiences, Social Interdependence, Children's Aggression, Victimization, and Prosocial Behaviors

Abstract: This study examined the relationships among cooperative experiences, social interdependence predispositions, harm-intended aggression, victimization, and prosocial behaviors with 217 elementary school children from 3rd to 5th grade. Path analysis using LISREL indicates that cooperative experiences predicted cooperative predispositions, the absence of individualistic predispositions, and prosocial behaviors. Cooperative predisposition predicted prosocial behaviors and the absence of harm-intended aggression. Competitive predisposition predicted harm-intended aggression. These findings validate social interdependence theory and partially support theories related to social dominance. Providing frequent cooperative learning experiences may be an important tool to increase students' cooperativeness and thereby reduce the frequency of harm-intended aggression, increase the frequency of prosocial behaviors, and reduce students' individualistic predispositions.

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.