Experience with tacrolimus in children with steroid-resistant nephrotic syndrome

Children with steroid-resistant nephrotic syndrome (SRNS) are at risk of developing renal failure. We report here the results of a single-center retrospective observational study of the remission rate in pediatric patients with SNRS receiving tacrolimus. Serial renal biopsies from children on tacrolimus therapy were evaluated for tubulointerstitial fibrosis and transforming growth factor-β immunostaining. Of the 16 children with SRNS, 15 went into complete remission after a median of 120 days of therapy. Nine children were able to stop steroids, while the others were on tapering doses. Forty-seven percent had relapses, most of which were steroid-responsive. Serial renal biopsies were obtained from seven children after a median treatment duration of 24 months; two of these children had increased tubulointerstitial fibrosis and four showed increased transforming growth factor-β tissue staining. Children with worsening histological findings were younger. There was no significant association between tacrolimus exposure and biopsy changes, although the average trough level was higher in those children with worsening histological findings. In conclusion, tacrolimus may be a safe and effective alternative agent for inducing remission in children with SRNS. However, caution needs to be taken when prescribing this agent due to its narrow therapeutic index. Serial renal biopsies are necessary to check for subclinical nephrotoxicity, especially in younger children and those with higher trough levels

Nature’s nations: the shared conservation history of Canada and the USA

Historians often study the history of conservation within the confines of national borders, concentrating on the bureaucratic and political manifestations of policy within individual governments. Even studies of the popular expression of conservationist ideas are generally limited to the national or sub-national (province, state, etc.) scale. This paper suggests that conservationist discourse, policy and practice in Canada and the USA were the products of a significant cross-border movement of ideas and initiatives derived from common European sources. In addition, the historical development of common approaches to conservation in North America suggests, contrary to common assumptions, that Canada did not always lag behind the USA in terms of policy innovation. The basic tenets of conservation (i.e. state control over resource, class-based disdain for subsistence hunters and utilitarian approaches to resource management) have instead developed at similar time periods and along parallel ideological paths in Canada and the USA

Effects of Atmospheric Change and Agriculture on the Biogeochemistry and Microbial Ecology of Prairie Wetlands

Relatively little is known about the factors which regulate in water biogeochemical processes and food chains in prairie wetlands. Climatic warming, increased UV-radiation and agricultural activities will have interacting effects on these wetlands. We examined the effects of these processes on prairie wetland functioning and productivity with particular emphasis on production and cycling of organic carbon, especially dissolved organic carbon (DOC). Autotrophic and heterotrophic production are temperature dependent and temperature increases or decreases could affect production under more extreme climate change scenarios. DOC concentrations could decrease with increasing bacterial production and photolysis, leading to increases in UV-radiation penetration. This is pertinent to prairie wetlands because of their general shallowness. Considering the potential consequences of climatic warming, increased UV-radiation and agricultural activity on biogeochemistry and food chains, it is imperative that we obtain an understanding of the major rate processes in prairie wetlands and how these may be affected by external processes

De novo hemolytic uremic syndrome postrenal transplant after cytomegalovirus infection

After renal transplantation, hemolytic uremic syndrome (HUS) may occur as recurrent disease or de novo. Here, we describe the de novo occurrence of HUS immediately after the onset of primary cytomegalovirus (CMV) disease in two renal allograft recipients. Patient no. 1 had primary CMV disease with biopsy-proven CMV esophagitis 2 months after transplantation. Patient no. 2 experienced primary CMV disease with fever and leukopenia 8 years after transplantation. Both patients were treated with intravenous ganciclovir. Both patients developed HUS with biopsy-proven thrombotic microangiopathy in the renal allograft only a few days (3 to 5 days) after the onset of CMV disease. The short interval between the onset of CMV disease and HUS, as well as the parallel course of CMV viremia and HUS in both patients, indicate there may be a pathophysiological link between both diseases. However, because antiviral therapy with ganciclovir was started before the onset of HUS in both patients, we cannot definitely rule out that HUS was triggered by ganciclovir

Sub-inhibitory concentrations of different pharmaceutical products affect the meta-transcriptome of river biofilm communities cultivated in rotating annular reactors

Surface waters worldwide are contaminated by pharmaceutical products that are released into the environment from wastewater treatment plants. Here, we hypothesize that pharmaceutical products have effects on organisms as well as genes related to nutrient cycling in complex microbial communities. To test this hypothesis, biofilms were grown in reactors and subjected low concentrations of three antibiotics [erythromycin, ER, sulfamethoxazole, SL and sulfamethazine, SN) and a lipid regulator (gemfibrozil, GM). Total community RNA was extracted and sequenced together with PCR amplicons of the 16S rRNA gene using 454 pyrosequencing. Exposure to pharmaceutical products resulted in very little change in bacterial community composition at the phylum level based on 16S rRNA gene amplicons, even though some genera were significantly affected. In contrast, large shifts were observed in the active community composition based on taxonomic affiliations of mRNA sequences. Consequently, expression of gene categories related to N, P and C cycling were strongly affected by the presence of pharmaceutical products, with each treatment having specific effects. These results indicate that low pharmaceutical product concentrations rapidly provoke a variety of functional shifts in river bacterial communities. In the longer term these shifts in gene expression and microbial activity could lead to a disruption of important ecosystem processes like nutrient cycling.Peer reviewed: YesNRC publication: Ye

Metatranscriptomic Analysis of the Response of River Biofilms to Pharmaceutical Products, Using Anonymous DNA Microarrays ▿ †

Pharmaceutical products are released at low concentrations into aquatic environments following domestic wastewater treatment. Such low concentrations have been shown to induce transcriptional responses in microorganisms, which could have consequences on aquatic ecosystem dynamics. In order to test if these transcriptional responses could also be observed in complex river microbial communities, biofilm reactors were inoculated with water from two rivers of differing trophic statuses and subsequently treated with environmentally relevant doses (ng/liter to μg/liter range) of four pharmaceuticals (erythromycin [ER], gemfibrozil [GM], sulfamethazine [SN], and sulfamethoxazole [SL]). To monitor functional gene expression, we constructed a 9,600-feature anonymous DNA microarray platform onto which cDNA from the biofilms was hybridized. Pharmaceutical treatments induced both positive and negative transcriptional responses from biofilm microorganisms. For instance, ER induced the transcription of several stress, transcription, and replication genes, while GM, a lipid regulator, induced transcriptional responses from several genes involved in lipid metabolism. SN caused shifts in genes involved in energy production and conversion, and SL induced responses from a range of cell membrane and outer envelope genes, which in turn could affect biofilm formation. The results presented here demonstrate for the first time that low concentrations of small molecules can induce transcriptional changes in a complex microbial community. The relevance of these results also demonstrates the usefulness of anonymous DNA microarrays for large-scale metatranscriptomic studies of communities from differing aquatic ecosystems

Next-generation sequencing of microbial communities in the athabasca river and its tributaries in relation to oil sands mining activities

The Athabasca oil sands deposit is the largest reservoir of crude bitumen in the world. Recently, the soaring demand for oil and the availability of modern bitumen extraction technology have heightened exploitation of this reservoir and the potential unintended consequences of pollution in the Athabasca River. The main objective of the present study was to evaluate the potential impacts of oil sands mining on neighboring aquatic microbial community structure. Microbial communities were sampled from sediments in the Athabasca River and its tributaries as well as in oil sands tailings ponds. Bacterial and archaeal 16S rRNA genes were amplified and sequenced using next-generation sequencing technology (454 and Ion Torrent). Sediments were also analyzed for a variety of chemical and physical characteristics. Microbial communities in the fine tailings of the tailings ponds were strikingly distinct from those in the Athabasca River and tributary sediments. Microbial communities in sediments taken close to tailings ponds were more similar to those in the fine tailings of the tailings ponds than to the ones from sediments further away. Additionally, bacterial diversity was significantly lower in tailings pond sediments. Several taxonomic groups of Bacteria and Archaea showed significant correlations with the concentrations of different contaminants, highlighting their potential as bioindicators. We also extensively validated Ion Torrent sequencing in the context of environmental studies by comparing Ion Torrent and 454 data sets and by analyzing control samples. \ua9 2012, American Society for Microbiology.Peer reviewed: YesNRC publication: Ye