Efficacy of mycophenolate mofetil in patients with diffuse proliferative lupus nephritis

Background: The combination of cyclophosphamide and prednisolone is effective for the treatment of severe lupus nephritis but has serious adverse effects. Whether mycophenolate mofetil can be substituted for cyclophosphamide is not known. Methods: In 42 patients with diffuse proliferative lupus nephritis we compared the efficacy and side effects of a regimen of prednisolone and mycophenolate mofetil given for 12 months with those of a regimen of prednisolone and cyclophosphamide given for 6 months, followed by prednisolone and azathioprine for 6 months. Complete remission was defined as a value for urinary protein excretion that was less than 0.3 g per 24 hours, with normal urinary sediment, a normal serum albumin concentration, and values for serum creatinine and creatinine clearance that were no more than 15 percent above the base-line values. Partial remission was defined as a value for urinary protein excretion that was between 0.3 and 2.9 g per 24 hours, with a serum albumin concentration of at least 3.0 g per deciliter. Results: Eighty-one percent of the 21 patients treated with mycophenolate mofetil and prednisolone (group 1) had a complete remission, and 14 percent had a partial remission, as compared with 76 percent and 14 percent, respectively, of the 21 patients treated with cyclophosphamide and prednisolone followed by azathioprine and prednisolone (group 2). The improvements in the degree of protelnuria and the serum albumin and creatinine concentrations were similar in the two groups. One patient in each group discontinued treatment because of side effects. Infections were noted in 19 percent of the patients in group 1 and in 33 percent of those in group 2 (P=0.29). Other adverse effects occurred only in group 2; they included amenorrhea (in 23 percent of the patients), hair loss (19 percent), leukopenia (10 percent), and death (10 percent). The rates of relapse were 15 percent and 11 percent, respectively. Conclusions: For the treatment of diffuse proliferative lupus nephritis, the combination of mycophenolate mofetil and prednisolone is as effective as a regimen of cyclophosphamide and prednisolone followed by azathioprine and prednisolone. (C) 2000, Massachusetts Medical Society.published_or_final_versio

Promotion of collaboration between medical and dental professionals

Includes bibliographical references (p. 25-26).published_or_final_versio

Trait-based community and invasion ecology of terrestrial arthropods

The search for general rules that predict the form, function and fate of biodiversity is an enduring goal in Ecology. Traits which impact the interactions and fitness of organisms have emerged as useful common currency with which to formulate general and predictive rules about ecological processes. A trait-based framework of community assembly will help to elucidate how ubiquitous processes such as interspecific competition shape and maintain biodiversity, and to predict the impacts of environmental change such as invasions by non-native species. Advances in both areas are needed to explain and address recent widespread changes in the diversity of terrestrial arthropods, organisms representing a massive and functionally significant portion of life on Earth. In this thesis I first review the burgeoning field of terrestrial arthropod trait-based ecology (Chapter 2). Studying ant assemblages in subtropical Asia, I then use trait-based approaches to investigate the mechanistic causes and functional consequences of assembly processes such as interspecific competition, within the context of invasions by non-native species. I find that invasion leads to a functional homogenization across the landscape which, notably, is unmet by comparable changes in taxonomic diversity (Chapter 3). To investigate underlying processes, I test whether differences in ant species’ morphological traits predict their fine-scale spatial associations in ways consistent with theories on interspecific competition (Chapter 4). At the assemblage level, I then show that two opposing mechanisms of competitive exclusion act varyingly on separate morphological, physiological and behavioural traits, causing the invasion to drive contrasting patterns in functional structure (Chapter 5). Addressing a key limitation of trait-based research, I also demonstrate empirically that decisions to exclude intraspecific trait variability from functional diversity assessments can distort the patterns observed, even overturning the conclusions drawn (Chapter 6). My work strengthens the foundations for a predictive trait-based ecology of animals in general. It makes specific empirical and methodological contributions to the use of traits for understanding community assembly and the competitive mechanisms determining the impacts of invasions on functional diversity. Building on the work described in this thesis, studies investigating how individual and multidimensional traits determine niche and competitive differences between species will further steer Ecology towards general rules for a predictive understanding of biodiversity and associated ecosystem functions.</p

Including intraspecific trait variability to avoid distortion of functional diversity and ecological inference: Lessons from natural assemblages

Functional diversity assessments are crucial and increasingly used for understanding ecological processes and managing ecosystems. The functional diversity of a community is assessed by sampling traits at one or more scales (individuals, populations and species) and calculating a summary index of the variation in trait values. However, it remains unclear how the scales at which traits are sampled and the indices used to estimate functional diversity may alter the patterns observed and inferences about ecological processes. For 40 plant and 61 ant communities, we assess functional diversity using six methods—spanning various mean‐based and probabilistic methods—that reflect common scenarios where different levels of detail are available in trait data. We test whether including trait variability at different scales (from individuals to species) alters functional diversity values calculated using the volume‐based and dissimilarity‐based indices, Functional Richness (FRic) and Rao, respectively. We further test whether such effects alter functional diversity patterns observed across communities and their relationships with environmental drivers such as abiotic gradients and occurrences of invasive species. Intraspecific trait variability strongly determined FRic and Rao. Methods using only species' mean trait values to calculate FRic (convex hulls) and Rao (Gower‐based dissimilarity) distorted the patterns observed when intraspecific trait variability was considered. These distortions generated Type I and Type II errors for the effects of environmental factors structuring the plant and ant communities. A high sensitivity of FRic to individuals with extreme trait values was revealed in comparisons of different probabilistic methods including among‐individual and among‐population trait variability in functional diversity. In contrast, values of and ecological patterns in Rao were consistent among methods including different scales of intraspecific trait variability. Our results show empirically that decisions about where traits are sampled and how trait variability is included in functional diversity can drastically change the patterns observed and conclusions about ecological processes. We recommend sampling the traits of multiple individuals per species and capturing their intraspecific trait variability using probabilistic methods. We discuss how intraspecific trait variability can be reasonably estimated and included in functional diversity in the common circumstance where only limited trait data are available

Aenictus seletarius, a New Species of Hypogaeic Army Ant from Singapore, with an Updated Key to the Aenictus minutulus Species Group (Hymenoptera: Formicidae: Dorylinae) from Southeast Asia

A new species of the army ant genus Aenictus (Hymenoptera: Formicidae: Dorylinae) is described. Aenictus seletarius sp. nov., belonging to the Aenictus minutulus species group, was discovered from a single subterranean pitfall trap in Singapore. Like A. subterraneus and A. changmaianus in this species group, A. seletarius displays substantial variation in body size within the worker caste. An updated key to the Aenictus minutulus species group from Southeast Asia is presented

The cryptic impacts of invasion: functional homogenization of tropical ant communities by invasive fire ants

The diversity and distribution of traits in an ecological community shapes its responses to change and the ecosystem processes it modulates. This ‘functional diversity’, however, is not necessarily a direct outcome of taxonomic diversity. Invasions by exotic insects occur in ecosystems worldwide, but there is limited understanding of how they impact functional diversity. We present the first comprehensive trait‐based investigation of the impacts of an ant invasion, and the first incorporating intraspecific polymorphisms in species‐level functional diversity. The fire ant Solenopsis invicta is an invasive species with a global distribution. Focusing on invaded and uninvaded plots in tropical grasslands of Hong Kong, we investigated how the presence of S. invicta affects the diversity and distribution of ant species and traits within and across communities, the functional identities of communities, and functionally unique species. Using trait probability density functions, we built trait spaces for 29 different species, and scaled up these components to calculate functional diversity at community and landscape levels. We found that invasion had limited effects on species and functional richness but pronounced effects on functional composition. Specifically, invaded communities had fewer functionally‐unique individuals, and were characterized by species with narrower heads and bodies and shorter mandibles. Moreover, invaded communities showed substantially higher levels of functional redundancy (+56%) due to a clustering of trait values. Consequently, across the landscape, invaded communities displayed 23% less functional turnover than uninvaded communities despite showing comparable levels of taxonomic turnover – a result confirming theoretical predictions of the effects of high local functional redundancy. In sum, the presence of S. invicta alters the functional properties of multiple local communities selectively, resulting in functional homogenization across the landscape. The disparities between taxonomic and functional impacts of invasion highlight the need to consider how trait diversity across ecological scales shapes biodiversity and its responses to change

Trait-mediated competition drives an ant invasion and alters functional diversity

The assumption that differences in species’ traits reflect their different niches has long influenced how ecologists infer processes from assemblage patterns. For instance, many assess the importance of environmental filtering versus classical limiting-similarity competition in driving biological invasions by examining whether invaders’ traits are similar or dissimilar to those of residents, respectively. However, mounting evidence suggests that hierarchical differences between species’ trait values can distinguish their competitive abilities (e.g., for the same resource) instead of their niches. Whether such trait-mediated hierarchical competition explains invasions and structures assemblages is less explored. We integrate morphological, dietary, physiological and behavioural trait analyses to test whether environmental filtering, limiting-similarity competition, or hierarchical competition explain invasions by fire ants on ant assemblages. We detect both competition mechanisms; invasion success is not only explained by limiting similarity in body size and thermal tolerance (presumably allowing the invader to exploit different niches from residents), but also by the invader’s superior position in trait hierarchies reflecting competition for common trophic resources. We find that the two mechanisms generate complex assemblage-level functional diversity patterns – overdispersion in some traits, clustering in others – suggesting their effects are likely missed by analyses restricted to a few traits and composite trait diversity measures

A study of the clinical and biochemical profile of peritoneal dialysis fluid low in glucose degradation products

OBJECTIVE: Although peritoneal dialysis (PD) is a widely accepted form of renal replacement therapy, concerns remain regarding the bioincompatible nature of standard PD fluid (PDF). Short-term studies of new biocompatible PDFs low in glucose degradation products (GDPs) reveal divergent results with respect to peritoneal integrity. METHODS: We studied 125 patients on maintenance PD who were assigned, by simple randomization, to receive either conventional or low-GDP PDF at PD initiation. Parameters of dialysis adequacy and peritoneal transport of small solutes were determined at initiation and after a period of maintenance PD at the time when serum and overnight effluent dialysate were simultaneously collected and assayed for various cytokines, chemokines, adipokines, and cardiac biomarkers. All patients were further followed prospectively for an average of 15 months from the day of serum and effluent collection to determine patient survival and cardiovascular events. RESULTS: Patients treated with conventional or low-GDP PDF were matched for sex, age, duration of dialysis, dialysis adequacy, and incidence of cardiovascular disease or diabetes. After an average of 2.3 years of PD treatment, the weekly total and peritoneal creatinine clearance, and the total and peritoneal Kt/V were comparable in the groups. However, urine output was higher in patients using low-GDP PDF despite there having been no difference between the groups at PD initiation. Patients using low-GDP PDF also experienced a slower rate of decline of residual glomerular filtration and urine output than did patients on conventional PDF. Compared with serum concentrations, effluent concentrations of tumor necrosis factor alpha, hepatocyte growth factor, macrophage migration inhibitory factor, interleukins 8 and 6, C-reactive protein, and leptin were found to be higher in both groups of patients after long-term PD, suggesting that the peritoneal cavity was the major source of those mediators. Compared with patients on low-GDP PDF, patients on conventional fluid showed elevated leptin and reduced adiponectin levels in serum and effluent. The effluent concentration of interleukin 8 was significantly lower in patients using low-GDP PDF. The survival rate and incidence of cardiovascular complications did not differ between these groups after maintenance PD for an average of 3.6 years. CONCLUSIONS: It appears that low-GDP PDF results in an improvement of local peritoneal homeostasis through a reduction of chronic inflammatory status in the peritoneum.link_to_OA_fulltex