Non-Invasive Imaging of Acute Renal Allograft Rejection in Rats Using Small Animal 18F-FDG-PET

BACKGROUND: At present, renal grafts are the most common solid organ transplants world-wide. Given the importance of renal transplantation and the limitation of available donor kidneys, detailed analysis of factors that affect transplant survival are important. Despite the introduction of new and effective immunosuppressive drugs, acute cellular graft rejection (AR) is still a major risk for graft survival. Nowadays, AR can only be definitively by renal biopsy. However, biopsies carry a risk of renal transplant injury and loss. Most important, they can not be performed in patients taking anticoagulant drugs. METHODOLOGY/PRINCIPAL FINDINGS: We present a non-invasive, entirely image-based method to assess AR in an allogeneic rat renal transplantation model using small animal positron emission tomography (PET) and (18)F-fluorodeoxyglucose (FDG). 3 h after i.v. injection of 30 MBq FDG into adult uni-nephrectomized, allogeneically transplanted rats, tissue radioactivity of renal parenchyma was assessed in vivo by a small animal PET-scanner (post operative day (POD) 1,2,4, and 7) and post mortem dissection. The mean radioactivity (cps/mm(3) tissue) as well as the percent injected dose (%ID) was compared between graft and native reference kidney. Results were confirmed by histological and autoradiographic analysis. Healthy rats, rats with acute CSA nephrotoxicity, with acute tubular necrosis, and syngeneically transplanted rats served as controls. FDG-uptake was significantly elevated only in allogeneic grafts from POD 1 on when compared to the native kidney (%ID graft POD 1: 0.54+/-0.06; POD 2: 0.58+/-0.12; POD 4: 0.81+/-0.06; POD 7: 0.77+/-0.1; CTR: 0.22+/-0.01, n = 3-28). Renal FDG-uptake in vivo correlated with the results obtained by micro-autoradiography and the degree of inflammatory infiltrates observed in histology. CONCLUSIONS/SIGNIFICANCE: We propose that graft FDG-PET imaging is a new option to non-invasively, specifically, early detect, and follow-up acute renal rejection. This method is potentially useful to improve post-transplant rejection monitoring

Consensus on guidelines for stereotactic neurosurgery for psychiatric disorders

For patients with psychiatric illnesses remaining refractory to 'standard' therapies, neurosurgical procedures may be considered. Guidelines for safe and ethical conduct of such procedures have previously and independently been proposed by various local and regional expert groups

Classification and nomenclature of all human homeobox genes

<p>Abstract</p> <p>Background</p> <p>The homeobox genes are a large and diverse group of genes, many of which play important roles in the embryonic development of animals. Increasingly, homeobox genes are being compared between genomes in an attempt to understand the evolution of animal development. Despite their importance, the full diversity of human homeobox genes has not previously been described.</p> <p>Results</p> <p>We have identified all homeobox genes and pseudogenes in the euchromatic regions of the human genome, finding many unannotated, incorrectly annotated, unnamed, misnamed or misclassified genes and pseudogenes. We describe 300 human homeobox loci, which we divide into 235 probable functional genes and 65 probable pseudogenes. These totals include 3 genes with partial homeoboxes and 13 pseudogenes that lack homeoboxes but are clearly derived from homeobox genes. These figures exclude the repetitive <it>DUX1 </it>to <it>DUX5 </it>homeobox sequences of which we identified 35 probable pseudogenes, with many more expected in heterochromatic regions. Nomenclature is established for approximately 40 formerly unnamed loci, reflecting their evolutionary relationships to other loci in human and other species, and nomenclature revisions are proposed for around 30 other loci. We use a classification that recognizes 11 homeobox gene 'classes' subdivided into 102 homeobox gene 'families'.</p> <p>Conclusion</p> <p>We have conducted a comprehensive survey of homeobox genes and pseudogenes in the human genome, described many new loci, and revised the classification and nomenclature of homeobox genes. The classification scheme may be widely applicable to homeobox genes in other animal genomes and will facilitate comparative genomics of this important gene superclass.</p

A genome-wide genetic map of NB-LRR disease resistance loci in potato

Like all plants, potato has evolved a surveillance system consisting of a large array of genes encoding for immune receptors that confer resistance to pathogens and pests. The majority of these so-called resistance or R proteins belong to the super-family that harbour a nucleotide binding and a leucine-rich-repeat domain (NB-LRR). Here, sequence information of the conserved NB domain was used to investigate the genome-wide genetic distribution of the NB-LRR resistance gene loci in potato. We analysed the sequences of 288 unique BAC clones selected using filter hybridisation screening of a BAC library of the diploid potato clone RH89-039-16 (S. tuberosum ssp. tuberosum) and a physical map of this BAC library. This resulted in the identification of 738 partial and full-length NB-LRR sequences. Based on homology of these sequences with known resistance genes, 280 and 448 sequences were classified as TIR-NB-LRR (TNL) and CC-NB-LRR (CNL) sequences, respectively. Genetic mapping revealed the presence of 15 TNL and 32 CNL loci. Thirty-six are novel, while three TNL loci and eight CNL loci are syntenic with previously identified functional resistance genes. The genetic map was complemented with 68 universal CAPS markers and 82 disease resistance trait loci described in literature, providing an excellent template for genetic studies and applied research in potato

A ruthenium(ii) bis(phosphinophosphinine) complex as a precatalyst for transfer-hydrogenation and hydrogen-borrowing reactions

The 2-phosphinophosphinine 2-PPh2-3-Me-6-SiMe3-PC5H2 (2) has been prepared and was shown to act as a κ2-chelating ligand in cis-[RuCl2(2)2] (4). Complex 4 was a competent precatalyst for the room temperature transfer hydrogenation of acetophenone (0.1 mol% 4 and 0.5 mol% KOtBu) and the conversion of methanol/ethanol mixtures to the advanced biofuel isobutanol in 50% yield and 96% selectivity

Functional analysis of tomato genes expressed during the Cf-4/Avr4-induced hypersensitive response

Plant diseases caused by pathogenic micro-organisms can result in severe crop losses and are a threat for global food and feed production and quality. Resistance breeding based on the introduction of a single dominant resistance gene is often not durable, as under selection pressure pathogens are able to overcome resistance by circumventing recognition by the host. After perception of a pathogen by a plant many different defense signaling pathways are activated, which are likely more difficult to avoid by the pathogen than the initial recognition event. Furthermore, these downstream responses are probably conserved among different plant species and are effective against different pathogens. The goal of the present study is to employ the tomato- Cladosporium fulvum interaction as a model to identify genes involved in defense signaling pathways. Identification of these genes increases our understanding of cellular responses of plants resistant to pathogens. This knowledge should eventually be exploited to develop durable resistant plants, either by marker-assisted breeding or by transgenesis.C. fulvumis a foliar, biotrophic fungal pathogen which causes leaf mold disease of tomato. In resistant tomato plants, within one to two days post penetration a microscopic H ypersensitive R esponse (HR) is observed preventing further growth of the biotrophic fungus. Tomato is the only host for C. fulvum and recognition of specific avirulence (Avr) factors encoded by Avr genes of the fungus is mediated by matching resistance proteins encoded by Cf genes of the plant, following the gene-for-gene model. Besides this host-specific and gene-for-gene-based resistance, mechanisms providing passive- and active- non-host resistance and some of the downstream defense responses are presented in a short overview (chapter 1).To identify genes required for Cf/Avr- induced defense pathways, we used a system that allows synchronized induction of defense responses by one Cf/Avr gene pair without the interference of additional fungal genes or proteins, referred to as the "dying seedling system". Therefore, a near-isogenic tomato line carrying Cf-4 was crossed to tomato transgenic for the Avr4 gene (and lacking functional Cf genes), resulting in offspring carrying the Cf-4/Avr4 gene pair. When such plants are grown at 33ºC the HR is suppressed. Subsequent shifting these plants to room temperature results in a synchronized HR. RNA was isolated from Cf-4 controls and Cf-4/Avr4 seedlings at 0, 30, 60 and 90 minutes after the temperature shift and subsequently cDNA-AFLP analysis was performed. This resulted in 442 differentially expressed cDNA-AFLP fragments corresponding to genes putatively involved in plant defense, designated A vr4- R esponsive T omato ( ART ) genes. To determine the requirement of the corresponding genes for plant defense V irus- I nduced G ene S ilencing (VIGS), a technique that allows generating fast transient individual "knock-downs" of relatively large sets of genes, was used. We first generated knock-downs for a set of 192 selected ART fragments in Nicotiana benthamiana transgenic for Cf-4 . VIGS of ART genes encoding a heat shock protein 90, a nuclear GTPase, an L19 ribosomal protein and, most interestingly, an NB-LRR protein clearly affected both Cf-4/Avr4- and Inf1- induced HR. The latter is an elicitor of Phytophthora infestans on its non-host N. benthamiana . Since VIGS using the ART fragment encoding the NB-LRR protein affected both the Cf-4/Avr4 and Inf1- induced HR in N. benthamiana, the protein was designated NRC1 ( N B-LRR R equired for HR-associated C ell death 1) (chapter 2) .Chapter 3describes the high-throughput functional analysis using VIGS in tomato to score for genes required for resistance to C. fulvum. VIGS was optimized in tomato using a fragment of the phytoene desaturase ( PDS ) gene. Successful silencing of PDS is visible as white tissue, thus providing a visual marker for silencing. Subsequently, VIGS of the resistance gene Cf-4 and a gene required for Cf-2- mediated resistance, Rcr3 was performed and in addition, a method to sensitively detect growth of C. fulvum in tomato leaves was optimized . Finally, we performed VIGS using the 192 selected ART fragments followed by inoculation with the fungus. VIGS using four of the selected 192 ART fragments, encoding a histon H3 protein, a ribosomal protein L1, an unknown protein and the NB-LRR protein, resulted in decreased resistance of tomato to C. fulvum.The research described in chapter 4 is focused on the NRC1 gene , which is the first NB-LRR encoding gene required for Cf- mediated defense. Although NRC1 proved to be required for multiple HR pathways, silencing of the gene only affected resistance to C. fulvum . Transient expression of a constitutively active mutant of NRC1 resulted in an elicitor-independent HR. Epistasis experiments revealed that the NRC1-induced HR is dependent on MEK2, SGT1 and RAR1, but independent of NDR1. It is hypothesized that NRC1, required for multiple defense pathways and exerting its activity downstream of EDS1 and upstream of MEK2, is a key regulator of defense.In chapter 5 different mechanisms generating resistance to pathogens, that operate in plants and in mammals, are discussed. Knowledge of defense pathways and the identification of the genes involved might reveal components required for resistance to many different pathogens