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.

Standardised outcomes in nephrology – Haemodialysis (SONG-HD): study protocol for establishing a core outcome set in haemodialysis

Abstract: Chronic kidney disease is a significant contributor to mortality and morbidity worldwide, and the number of people who require dialysis or transplantation continues to increase. People on dialysis are 15 times more likely to die than the general population. Dialysis is also costly, intrusive, and time-consuming and imposes an enormous burden on patients and their families. This escalating problem has spurred a proliferation of trials in dialysis, yet health and quality of life remain poor. The reasons for this are complex and varied but are attributable in part to problems in the design and reporting of studies, particularly outcome selection. Problems related to outcomes include use of unvalidated surrogates, outcomes of little or no relevance to patients, highly variable outcome selection limiting comparability across studies, and bias in reporting outcomes. The aim of the Standardised Outcomes in Nephrology-Haemodialysis (SONG-HD) study is to establish a core outcome set for haemodialysis trials, to improve the quality of reporting, and the relevance of trials conducted in people on haemodialysis. SONG-HD is a five-phase project that includes the following: a systematic review to identify outcomes that have been reported in haemodialysis systematic reviews and trials; nominal group technique with patients and caregivers to identify, rank, and describe reasons for their choices; qualitative stakeholder interviews with patients, caregivers, clinicians, researchers, and policy makers to elicit individual values and perspectives on outcomes for haemodialysis trials; a three-round Delphi survey with stakeholder groups to distil and generate a prioritised list of core outcomes; and a consensus workshop to establish a core outcome set for haemodialysis trials. Establishing a core outcome set to be consistently measured and reported in haemodialysis trials will improve the integrity, transparency, usability, and contribution of research relevant to patients requiring haemodialysis; ensure that outcomes of relevance to all stakeholders are consistently reported across trials; and mitigate against outcome reporting bias. Ultimately, patients will be more protected from potential harm, patients and clinicians will be better able to make informed decisions about treatment, and researchers and policy makers will be more able to maximise the value of research to the public

Logging and soil nutrients independently explain plant trait expression in tropical forests

Abstract: Plant functional traits regulate ecosystem functions but little is known about how co-occurring gradients of land use and edaphic conditions influence their expression. We test how gradients of logging disturbance and soil properties relate to community-weighted mean traits in logged and old-growth tropical forests in Borneo. We studied 32 physical, chemical and physiological traits from 284 tree species in eight 1 ha plots and measured long-term soil nutrient supplies and plant-available nutrients. Logged plots had greater values for traits that drive carbon capture and growth, whilst old-growth forests had greater values for structural and persistence traits. Although disturbance was the primary driver of trait expression, soil nutrients explained a statistically independent axis of variation linked to leaf size and nutrient concentration. Soil characteristics influenced trait expression via nutrient availability, nutrient pools, and pH. Our finding, that traits have dissimilar responses to land use and soil resource availability, provides robust evidence for the need to consider the abiotic context of logging when predicting plant functional diversity across human-modified tropical forests. The detection of two independent axes was facilitated by the measurement of many more functional traits than have been examined in previous studies.

Compared with Younger Peritoneal Dialysis Patients, Elderly Patients Have Similar Peritonitis-Free Survival and Lower Risk of Technique Failure, But Higher Risk of Peritonitis-Related Mortality

Abstract: ♦ Background: The number of elderly patients with endstage kidney disease (ESKD) is increasing worldwide, but the proportion of elderly patients commencing peritoneal dialysis (PD) is falling. The reluctance of elderly ESKD patients to consider PD may be related to a perception that PD is associated with greater rates of complications. In the present study, we compared outcomes between younger and older PD patients. ♦ Methods: Using Australia and New Zealand Dialysis Registry data, all adult ESKD patients commencing PD between 1991 and 2007 were categorized into under 50, 50 – 64.9, and 65 years of age or older groups. Time to first peritonitis, death-censored technique failure, and peritonitis-associated and all-cause mortality were evaluated by multivariate Cox proportional hazards model analysis. ♦ Results: Of the 12 932 PD patients included in the study, 3370 (26%) were under 50 years of age, 4386 (34%) were 50 – 64.9 years of age, and 5176 (40%) were 65 years of age or older. Compared with younger patients (<50 years), elderly patients (≥65 years) had a similar peritonitis-free survival and a lower risk of death-censored technique failure [hazard ratio (HR): 0.85; 95% confidence interval (CI): 0.79 to 0.93], but they had higher peritonitis-related (HR: 2.31; 95% CI: 1.68 to 3.18) and all-cause mortality (HR: 2.90; 95% CI: 2.60 to 3.23). ♦ Conclusions: Not unexpectedly, elderly patients have higher peritonitis-related and all-cause mortality, which is likely a consequence of a greater prevalence of comorbid disease. However, compared with younger patients, elderly patients have superior technique survival and similar peritonitis-free survival, suggesting that PD is a viable renal replacement therapy in this group of patients.

Reoperation for intracranial hypertension in TWIST1-confirmed Saethre-Chotzen syndrome: a 15-year review.

Abstract: BACKGROUND: Saethre-Chotzen syndrome is a syndromic craniosynostosis defined by a genetic mutation affecting the TWIST1 gene on chromosome 7p21. It is typically associated with unicoronal or bicoronal synostosis, eyelid ptosis, dysmorphic external ears, and other variable facial and limb abnormalities. Surgical management of the craniosynostosis addresses the calvarial deformity and may relieve or reduce the risk of intracranial hypertension. The aim of this study was to assess surgical intervention, with particular consideration of the reoperation rate for intracranial hypertension, in Saethre-Chotzen syndrome patients. METHODS: A retrospective case note analysis was performed on all patients with a confirmed TWIST1 gene abnormality who attended the Oxford Craniofacial Unit over a 15-year period. Each patient's mutation and clinical features were recorded. Surgical intervention and sequelae were examined in greater detail. RESULTS: Thirty-four patients with genetically confirmed Saethre-Chotzen syndrome were identified. All had craniosynostosis (bicoronal, 76 percent; unicoronal, 18 percent; bicoronal and sagittal, 6 percent), and the majority had eyelid ptosis, low frontal hairline, and external ear anomalies. Thirty-one patients had received surgical intervention. Nine of 26 patients (35 percent) with at least 12 months of follow-up after primary intervention and eight of 19 patients (42 percent) with at least 5 years of follow-up developed intracranial hypertension necessitating secondary calvarial surgery. CONCLUSIONS: Despite standard surgical intervention, patients with Saethre-Chotzen syndrome have a high rate (35 to 42 percent) of recurrent intracranial hypertension necessitating further surgical expansion. All patients with either bicoronal synostosis or unicoronal synostosis with syndromic features should be screened for TWIST1 mutations, as this confers a greater risk than nonsyndromic synostosis of the same sutures. Regular follow-up throughout the childhood years is essential.

Influence strategy, perspective-taking, and relationships between high- and low-power individuals in cooperative and competitive contexts.

Abstract: Summary Sixty-four undergraduates negotiated an exchange of resources in dyads. They had either high or low power relative to the other and negotiated within a cooperative or a competitive context. The results indicate that within a competitive context unequal-power relationships resulted in the higher-power person's use of coercion and the low-power person's attempts to negotiate. Both high- and low-power Ss perceived their relationship to be dominated by egocentric focus on one's own goals and attempts to control the other to meet one's needs. Within a cooperative context, however, both high- and low-power Ss were highly inducible to each other's influences, needed resources were provided to each other, high trust and liking occurred between Ss, and Ss were more accurate in understanding each other's perspectives. Unequal power seems to have undermined negotiations within a competitive context while not detracting from effective working relationships within a cooperative context.

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.