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.

Systematic Study of New Rare Earth Element−Iron−Antimony Skutterudites Synthesized Using Multilayer Precursors

Abstract: We have synthesized a series of stable and metastable rare earth element−iron antimonides, controlling both composition and structure using multilayer reactants. The stable rare earth iron element antimonides have the filled skutterudite structure (LaFe4P12) with a stoichiometry of 1 for the rare earth element. The metastable rare earth element−iron antimonides could be prepared with the entire sequence of rare earth elements. The lattice parameters of these metastable compounds were always larger than those of the corresponding more stable analog, and the occupancy of the rare earth element cation was found to be less than 1. Reitveld analysis of Lu1-xFe4Sb12 suggests that the late rare earth element compounds have a new distorted filled skutterudite structure. Structural trends are discussed in terms of their potential use as thermoelectric materials.

Effect of previously failed kidney transplantation on peritoneal dialysis outcomes in the Australian and New Zealand patient populations

Abstract: Background. There is limited information about the outcomes of patients commencing peritoneal dialysis (PD) after failed kidney transplantation. The aim of the present study was to compare patient survival, death-censored technique survival and peritonitis-free survival between patients initiating PD after failed renal allografts and those after failed native kidneys. Methods. The study included all patients from the ANZDATA Registry who started PD between April 1, 1991 and March 31, 2004. Times to death, deathcensored technique failure and first peritonitis episode were examined by multivariate Cox proportional hazards models. For all outcomes, conditional risk set models were utilized for the multiple failure data, and analyses were stratified by failure order. Standard errors were calculated by using robust variance estimation for the cluster-correlated data. Results. In total, 13 947 episodes of PD were recorded in 23 579 person-years. Of these, 309 PD episodes were started after allograft failure. Compared with PD patients who had never undergone kidney transplantation, those with failed renal allografts were more likely to be younger, Caucasian, New Zealand residents and life-long non-smokers with lower body mass index (BMI), poorer initial renal function and a longer period from commencement of the first renal replacement therapy to PD. On multivariate analysis, PD patients with failed kidney transplants had comparable patient mortality [weighted hazards ratio (HR) 1.09, 95% confidence interval (CI) 0.81–1.45, P ¼ 0.582], death-censored technique failure (adjusted HR 0.91, 95% CI 0.75–1.10, P ¼ 0.315) and peritonitis-free survival (adjusted HR 0.92, 95% CI 0.72–1.16, P ¼ 0.444) with those PD patients who had failed native kidneys. Similar findings were observed in a subset of patients (n ¼ 5496) for whom peritoneal transport status was known and included in the models as a covariate. Conclusion. Patients commencing PD after renal allograft failure experienced outcomes comparable with those with failed native kidneys. PD appears to be a viable option for patients with failed kidney allografts.

Do aluminium-based phosphate binders continue to have a role in contemporary nephrology practice?

Abstract: Aluminium-containing phosphate binders have long been used for treatment of hyperphosphatemia in dialysis patients. Their safety became controversial in the early 1980's after reports of aluminium related neurological and bone disease began to appear. Available historical evidence however, suggests that neurological toxicity may have primarily been caused by excessive exposure to aluminium in dialysis fluid, rather than aluminium-containing oral phosphate binders. Limited evidence suggests that aluminium bone disease may also be on the decline in the era of aluminium removal from dialysis fluid, even with continued use of aluminium binders. The K/DOQI and KDIGO guidelines both suggest avoiding aluminium-containing binders. These guidelines will tend to promote the use of the newer, more expensive binders (lanthanum, sevelamer), which have limited evidence for benefit and, like aluminium, limited long-term safety data. Treating hyperphosphatemia in dialysis patients continues to represent a major challenge, and there is a large body of evidence linking serum phosphate concentrations with mortality. Most nephrologists agree that phosphate binders have the potential to meaningfully reduce mortality in dialysis patients. Aluminium is one of the cheapest, most effective and well tolerated of the class, however there are no prospective or randomised trials examining the efficacy and safety of aluminium as a binder. Aluminium continues to be used as a binder in Australia as well as some other countries, despite concern about the potential for toxicity. There are some data from selected case series that aluminium bone disease may be declining in the era of reduced aluminium content in dialysis fluid, due to rigorous water testing. This paper seeks to revisit the contemporary evidence for the safety record of aluminium-containing binders in dialysis patients. It puts their use into the context of the newer, more expensive binders and increasing concerns about the risks of calcium binders, which continue to be widely used. The paper seeks to answer whether the continued use of aluminium is justifiable in the absence of prospective data establishing its safety, and we call for prospective trials to be conducted comparing the available binders both in terms of efficacy and safety.

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.