Inhibition of LtxA Toxicity by Blocking Cholesterol Binding with Peptides

The leukotoxin (LtxA) produced by Aggregatibacter actinomycetemcomitans kills host immune cells, allowing the bacterium to establish an ecological niche in the upper aerodigestive tract of its human host. The interaction of LtxA with human immune cells is both complex and multifaceted, involving membrane lipids as well as cell-surface proteins. In the initial encounter with the host cell, LtxA associates with lymphocyte function-associated antigen-1, a cell surface adhesion glycoprotein. However, we have also demonstrated that the toxin associates strongly with the plasma membrane lipids, specifically cholesterol. This association with cholesterol is regulated by a cholesterol recognition amino acid consensus (CRAC) motif, with a sequence of 334LEEYSKR340, in the N-terminal region of the toxin. Here, we have demonstrated that removal of cholesterol from the plasma membrane or mutation of the LtxA CRAC motif inhibits the activity of the toxin in THP-1 cells. To inhibit LtxA activity, we designed a short peptide corresponding to the CRAC336 motif of LtxA (CRAC336WT). This peptide binds to cholesterol and thereby inhibits the toxicity of LtxA in THP-1 cells. Previously, we showed that this peptide inhibits LtxA toxicity against Jn.9 (Jurkat) cells, indicating that peptides derived from the cholesterol-binding site of LtxA may have a potential clinical applicability in controllinginfections of repeats-in-toxin-producing organisms. © 2016 John Wiley & Sons A/S

Survival and quality of life benefit after endoscopic management of malignant central airway obstruction

Although interventional management of malignant central airway obstruction (mCAO) is well established, its impact on survival and quality of life (QoL) has not been extensively studied.We prospectively assessed survival, QoL and dyspnea (using validated EORTC questionnaire) in patients with mCAO 1 day before interventional bronchoscopy, 1 week after and every following month, in comparison to patients who declined this approach. Material/Patients/Methods: 36 patients underwent extensive interventional bronchoscopic management as indicated, whereas 12 declined. All patients received full chemotherapy and radiotherapy as indicated. Patients of the 2 groups were matched for age, comorbidities, type of malignancy and level of obstruction. Follow up time was 8.0±8.7 (range 1-38) months.Mean survival for intervention and control group was 10±9 and 4±3 months respectively (p=0.04). QoL improved significantly in intervention group patients up to the 6(th) month (p<0.05) not deteriorating for those surviving up to 12 months. Dyspnea decreased in patients of the intervention group 1 month post procedure remaining reduced for survivors over the 12th month. Patients of the control group had worse QoL and dyspnea in all time points.Interventional management of patients with mCAO, may achieve prolonged survival with sustained significant improvement of QoL and dyspnea

Inhibition of LtxA Toxicity by Blocking Cholesterol Binding With Peptides

The leukotoxin (LtxA) produced by Aggregatibacter actinomycetemcomitans kills host immune cells, allowing the bacterium to establish an ecological niche in the upper aerodigestive tract of its human host. The interaction of LtxA with human immune cells is both complex and multifaceted, involving membrane lipids as well as cell-surface proteins. In the initial encounter with the host cell, LtxA associates with lymphocyte function-associated antigen-1 (LFA-1), a cell surface adhesion glycoprotein. However, we have also demonstrated that the toxin associates strongly with the plasma membrane lipids, specifically cholesterol. This association with cholesterol is regulated by a cholesterol recognition amino acid consensus (CRAC) motif, with a sequence of 334LEEYSKR340, in the N-terminal region of the toxin. Here, we have demonstrated that removal of cholesterol from the plasma membrane or mutation of the LtxA CRAC motif inhibits the activity of the toxin in THP-1 cells. To inhibit LtxA activity, we designed a short peptide corresponding to the CRAC336 motif of LtxA (CRAC336WT). This peptide binds to cholesterol and thereby inhibits the toxicity of LtxA in THP-1 cells. Previously, we showed that this peptide inhibits LtxA toxicity against Jn.9 (Jurkat) cells, indicating that peptides derived from the cholesterol-binding site of LtxA may have a potential clinical applicability in controlling infections of RTX-producing organisms

DEVELOPING A METHODOLOGICAL FRAMEWORK FOR THE PARTICIPATORY MEASUREMENT OF SUSTAINABILITY

The measurement of sustainability can provide significant information in order to plan and implement environmental policies. Several methods have been proposed in the literature in order to select the appropriate indicators along with a variety of techniques for their measurement. These methods are often divided in two main categories: a) a top-down approach where the selection of sustainability indicators is often based on the decision of scientists and policy-makers and b) a bottom-up approach where local stakeholders influence the selection and the measurement of indicators. In this paper we propose a methodological framework which allows the selection of sustainability indicators based on scientific research but at the same time allows citizens to influence both the selection of indicators and their measurement. The benefits of the specific methodological framework are two: a) to incorporate in different stages of the measurement the opinions of local stakeholders, b) to assist in policy decision-making through the assessment of the current situation of sustainability

New material of Laophis crotaloides, an enigmatic giant snake from Greece, with an overview of the largest fossil European vipers

Laophis crotaloides was described by Richard Owen as a new and very large fossil viperid snake species from Greece. The type material is apparently lost and the taxon was mostly neglected for more than a century. We here describe a new partial viperid vertebra, collected from the same locality and of equivalent size to the type material. This vertebra indicates that at least one of the three morphological characters that could be used to diagnose L. crotaloides is probably an artifact of the lithographer who prepared the illustration supporting the original description. A revised diagnosis of L. crotaloides is provided on the basis of the new specimen. Despite the fragmentary nature of the new vertebra, it confirms the validity of L. crotaloides, although its exact relationships within Viperidae remain unknown. The new find supports the presence of a large viperid snake in the early Pliocene of northern Greece, adding further data to the diversity of giant vipers from Europe

Raltitrexed (Tomudex) administration in patients with relapsed metastatic colorectal cancer after weekly irinotecan/5-Fluorouracil/Leucovorin chemotherapy

PURPOSE: The present study aimed at evaluating the efficacy of Raltitrexed, a specific thymidilate synthase inhibitor, in patients with advanced colorectal cancer (ACC) in relapse (>8 weeks) after a prior response or disease stabilization to first-line chemotherapy combination with lrinotecan+5-Fluorouracil (5-FU)+Leucovorin (LV). METHODS: Twenty-five patients with metastatic ACC entered; 17 males/8 females, median age 61 (range: 47–70), median Karnovsky PS: 80 (70–90), and sites of metastases; liver: 21, lung: 4, lymph nodes: 7, peritoneal: 5 and a life expectancy of at least 3 months, were entered in the present pilot study. All patients had progressed after prior chemotherapy with lrinotecan+5-FU+LV. Raltitrexed was administered at a dose of 3 mg/m(2) i.v. every 21 days. RESULTS: Three patients (12%) achieved a partial response (PR), 8 (32%) had stable disease (SD), and the remaining 14 (56%) developed progressive disease (PD). Median time-to-progression (TTP) was 5.5 months (range, 2–8.5), and median overall survival (OS) 8 months (range, 4.0–12.5). Toxicity was generally mild; it consisted mainly of myelosuppression; neutropenia grade 1–2: 52%-grade 3: 28%, and anemia grade 1–2 only: 36%. Mild mucositis grade 1–2 occured in 13.5% of patients and was the principal non-hematologic toxicity. CONCLUSION: Response to treatment with Raltitrexed is limited in patients with ACC failing after an initial response or non-progression to the weekly lrinotecan+5-FU+LV combination. However, it appears that a limited number of patients with PR/SD may derive clinical benefit, but final proof would require a randomized study

Kretzoiarctos gen. nov., the Oldest Member of the Giant Panda Clade

The phylogenetic position of the giant panda, Ailuropoda melanoleuca (Carnivora: Ursidae: Ailuropodinae), has been one of the most hotly debated topics by mammalian biologists and paleontologists during the last century. Based on molecular data, it is currently recognized as a true ursid, sister-taxon of the remaining extant bears, from which it would have diverged by the Early Miocene. However, from a paleobiogeographic and chronological perspective, the origin of the giant panda lineage has remained elusive due to the scarcity of the available Miocene fossil record. Until recently, the genus Ailurarctos from the Late Miocene of China (ca. 8–7 mya) was recognized as the oldest undoubted member of the Ailuropodinae, suggesting that the panda lineage might have originated from an Ursavus ancestor. The role of the purported ailuropodine Agriarctos, from the Miocene of Europe, in the origins of this clade has been generally dismissed due to the paucity of the available material. Here, we describe a new ailuropodine genus, Kretzoiarctos gen. nov., based on remains from two Middle Miocene (ca. 12–11 Ma) Spanish localities. A cladistic analysis of fossil and extant members of the Ursoidea confirms the inclusion of the new genus into the Ailuropodinae. Moreover, Kretzoiarctos precedes in time the previously-known, Late Miocene members of the giant panda clade from Eurasia (Agriarctos and Ailurarctos). The former can be therefore considered the oldest recorded member of the giant panda lineage, which has significant implications for understanding the origins of this clade from a paleobiogeographic viewpoint

First description of a fossil chamaeleonid from Greece and its relevance for the European biogeographic history of the group

The fossil record of Chamaeleonidae is very scarce and any new specimen is therefore considered important for our understanding of the evolutionary and biogeographic history of the group. New specimens from the early Miocene of Aliveri (Evia Island), Greece constitute the only fossils of these lizards from southeastern Europe. Skull roofing material is tentatively attributed to the Czech species Chamaeleo cf. andrusovi, revealing a range extension for this taxon, whereas tooth-bearing elements are described as indeterminate chamaeleonids. The Aliveri fossils rank well among the oldest known reptiles from Greece, provide evidence for the dispersal routes of chameleons out of Africa towards the European continent and, additionally, imply strong affinities with coeval chamaeleonids from Central Europe

A Genome-Wide Homozygosity Association Study Identifies Runs of Homozygosity Associated with Rheumatoid Arthritis in the Human Major Histocompatibility Complex

Rheumatoid arthritis (RA) is a chronic inflammatory disorder with a polygenic mode of inheritance. This study examined the hypothesis that runs of homozygosity (ROHs) play a recessive-acting role in the underlying RA genetic mechanism and identified RA-associated ROHs. Ours is the first genome-wide homozygosity association study for RA and characterized the ROH patterns associated with RA in the genomes of 2,000 RA patients and 3,000 normal controls of the Wellcome Trust Case Control Consortium. Genome scans consistently pinpointed two regions within the human major histocompatibility complex region containing RA-associated ROHs. The first region is from 32,451,664 bp to 32,846,093 bp (−log10(p)>22.6591). RA-susceptibility genes, such as HLA-DRB1, are contained in this region. The second region ranges from 32,933,485 bp to 33,585,118 bp (−log10(p)>8.3644) and contains other HLA-DPA1 and HLA-DPB1 genes. These two regions are physically close but are located in different blocks of linkage disequilibrium, and ∼40% of the RA patients' genomes carry these ROHs in the two regions. By analyzing homozygote intensities, an ROH that is anchored by the single nucleotide polymorphism rs2027852 and flanked by HLA-DRB6 and HLA-DRB1 was found associated with increased risk for RA. The presence of this risky ROH provides a 62% accuracy to predict RA disease status. An independent genomic dataset from 868 RA patients and 1,194 control subjects of the North American Rheumatoid Arthritis Consortium successfully validated the results obtained using the Wellcome Trust Case Control Consortium data. In conclusion, this genome-wide homozygosity association study provides an alternative to allelic association mapping for the identification of recessive variants responsible for RA. The identified RA-associated ROHs uncover recessive components and missing heritability associated with RA and other autoimmune diseases

Bone histology provides insights into the life history mechanisms underlying dwarfing in hipparionins

Size shifts may be a by-product of alterations in life history traits driven by natural selection. Although this approach has been proposed for islands, it has not yet been explored in continental faunas. The trends towards size decrease experienced by some hipparionins constitute a good case study for the application of a life history framework to understand the size shifts on the continent. Here, we analysed bone microstructure to reconstruct the growth of some different-sized hipparionins from Greece and Spain. The two dwarfed lineages studied show different growth strategies. The Greek hipparions ceased growth early at a small size thus advancing maturity, whilst the slower-growing Spanish hipparion matured later at a small size. Based on predictive life history models, we suggest that high adult mortality was the likely selective force behind early maturity and associated size decrease in the Greek lineage. Conversely, we infer that resource limitation accompanied by high juvenile mortality triggered decrease in growth rate and a relative late maturity in the Spanish lineage. Our results provide evidence that different selective pressures can precipitate different changes in life history that lead to similar size shifts