Glycosaminoglycans and Sialylated Glycans Sequentially Facilitate Merkel Cell Polyomavirus Infectious Entry

Merkel cell polyomavirus (MCV or MCPyV) appears to be a causal factor in the development of Merkel cell carcinoma, a rare but highly lethal form of skin cancer. Although recent reports indicate that MCV virions are commonly shed from apparently healthy human skin, the precise cellular tropism of the virus in healthy subjects remains unclear. To begin to explore this question, we set out to identify the cellular receptors or co-receptors required for the infectious entry of MCV. Although several previously studied polyomavirus species have been shown to bind to cell surface sialic acid residues associated with glycolipids or glycoproteins, we found that sialylated glycans are not required for initial attachment of MCV virions to cultured human cell lines. Instead, glycosaminoglycans (GAGs), such as heparan sulfate (HS) and chondroitin sulfate (CS), serve as initial attachment receptors during the MCV infectious entry process. Using cell lines deficient in GAG biosynthesis, we found that N-sulfated and/or 6-O-sulfated forms of HS mediate infectious entry of MCV reporter vectors, while CS appears to be dispensable. Intriguingly, although cell lines deficient in sialylated glycans readily bind MCV capsids, the cells are highly resistant to MCV reporter vector-mediated gene transduction. This suggests that sialylated glycans play a post-attachment role in the infectious entry process. Results observed using MCV reporter vectors were confirmed using a novel system for infectious propagation of native MCV virions. Taken together, the findings suggest a model in which MCV infectious entry occurs via initial cell binding mediated primarily by HS, followed by secondary interactions with a sialylated entry co-factor. The study should facilitate the development of inhibitors of MCV infection and help shed light on the infectious entry pathways and cellular tropism of the virus

Chromosome evolution in Cophomantini (Amphibia, Anura, Hylinae)

The hylid tribe Cophomantini is a diverse clade of Neotropical treefrogs composed of the genera Aplastodiscus, Boana, Bokermannohyla, Hyloscirtus, and Myersiohyla. The phylogenetic relationships of Cophomantini have been comprehensively reviewed in the literature, providing a suitable framework for the study of chromosome evolution. Employing different banding techniques, we studied the chromosomes of 25 species of Boana and 3 of Hyloscirtus; thus providing, for the first time, data for Hyloscirtus and for 15 species of Boana. Most species showed karyotypes with 2n = 2x = 24 chromosomes; some species of the B. albopunctata group have 2n = 2x = 22, and H. alytolylax has 2n = 2x = 20. Karyotypes are all bi-armed in most species presented, with the exception of H. larinopygion (FN = 46) and H. alytolylax (FN = 38), with karyotypes that have a single pair of small telocentric chromosomes. In most species of Boana, NORs are observed in a single pair of chromosomes, mostly in the small chromosomes, although in some species of the B. albopunctata, B. pulchella, and B. semilineata groups, this marker occurs on the larger pairs 8, 1, and 7, respectively. In Hyloscirtus, NOR position differs in the three studied species: H. alytolylax (4p), H. palmeri (4q), and H. larinopygion (1p). Heterochromatin is a variable marker that could provide valuable evidence, but it would be necesserary to understand the molecular composition of the C-bands that are observed in different species in order to test its putative homology. In H. alytolylax, a centromeric DAPI+ band was observed on one homologue of chromosome pair 2. The band was present in males but absent in females, providing evidence for an XX/XY sex determining system in this species. We review and discuss the importance of the different chromosome markers (NOR position, C-bands, and DAPI/CMA3 patterns) for their impact on the taxonomy and karyotype evolution in Cophomantini

Depenalization, diversion and decriminalization: A realist review and programme theory of alternatives to criminalization for simple drug possession

Alternatives to criminalization for the simple possession of illicit drugs are increasingly of interest to policy makers. But there is no existing theoretically based, empirically tested framework that can inform development and evaluation. This article presents a realist programme theory of such alternatives. It bases this on a realist review, which followed the Realist and Meta-narrative Evidence Syntheses: Evolving Standards (RAMESES). It describes the systematic process of searching the literature in English on nine relevant countries (Australia, Czech Republic, Denmark, Germany, Jamaica, Netherland, Portugal, the UK, the USA) for information on alternative measures in three categories: depenalization; diversion; and decriminalization. It shows how these measures – in theory and in practice – combine with pre-existing social conditions and institutional contexts to trigger mechanisms across three causal pathways (normative; criminal justice; and health and social services). It shows how some posited causal processes are more empirically supported than others. Alternative measures can reduce harms imposed by criminal justice processes without increasing drug use or related health and crime harms, but this depends on specific combinations of contexts, mechanisms and outcomes

Legume allergy: clinical threshold doses in legume-allergic individuals

Background Soybean and peanut, members of the Legume family, are recognized as common allergenic foods by the FAO Codex Alimentarius. EU directive 2003/89/EC and US Food Allergen Labeling and Consumer Protection Act prescribe labelling of food products for these two major allergenic foods. EU directive 2007/68/EC requires labelling for lupin, another member of the Legume family. The reported prevalence and severity of allergic reactions to soybeans is lower than peanut and most other major allergenic foods. For lupin only limited clinical data are available. Our previous work with peanut has used clinical results from double-blind, placebo-controlled food challenges (DBPCFC) to estimate a population threshold. Further exploration of soy and lupin thresholds would benefit all stakeholders. Methods Publications were screened for DBPCFCs providing lowest observed adverse effect level (LOAEL) and/or no observed adverse effect level (NOAEL) for soy- or lupin-allergic individuals. Unpublished data were retrieved from diagnostic DBPCFCs from the UMCU outpatient population. LOAELs were based upon elicitation of objective symptoms. All doses were converted to mg protein to standardize challenge materials across studies. Individual thresholds were analyzed using Interval-Censoring Survival Analysis and fitted to parametric models (Log-Normal, Log-Logistic, and Weibul) using LIFEREG procedure (SAS v9.2). The eliciting dose predicted to provoke reactions in a proportion of the allergic population(EDp) was estimated and compared to the known peanut-allergic population. Results Public literature revealed clinical thresholds of 43 soy-allergic individuals in 4 studies and 9 lupin-allergic individuals in 3 studies. An additional 15 unpublished lupin DBPCFC were retrieved. Comparison of the ED doses indicate that soy and lupin are less potent allergenic foods than peanut. Using the Log-Normal distributions, the ED05 for peanut is 1.3 mg peanut protein while the ED05 for lupin is 19.1 mg lupin protein and soybean is 24.5 mg soy protein. However, the lowest eliciting dose observed for each group of allergic individuals is 36 mg lupin protein and 88 mg soy protein, considerably higher than the predicted ED05. Conclusion The eliciting dose for allergic reactions of three members of the Legume family showed a different potency for peanut, lupin, and soybean. Additional clinical data from soy and/or lupin challenges would be valuable to increase the statistical confidence in the population threshold estimates

Threshold Dose Distribution in Walnut Allergy

BACKGROUND: In food allergy, eliciting doses (EDs) of foods on a population level can improve risk management and labeling strategies for the food industry and regulatory authorities. Previously, data available for walnut were unsuitable to determine EDs. OBJECTIVE: The objective of this study was to determine EDs for walnut allergic adults and to compare with previously established threshold data for peanut and tree nuts. METHODS: Prospectively, adult subjects with a suspected walnut allergy underwent a low-dose double-blind, placebo-controlled food challenge. Individual no observed and lowest observed adverse effect levels were determined and log-normal, log-logistic, and Weibull models were fit to the data. Estimated ED values were calculated for the ED5, ED10, and ED50, the dose respectively predicted to provoke an allergic reaction in 5%, 10%, and 50% of the walnut allergic population. RESULTS: Fifty-seven subjects were challenged and 33 subjects were confirmed to be walnut allergic. Objective symptoms occurred in 20 of the positive challenges (61%). The cumulative EDs in the distribution models ranged from 3.1 to 4.1 mg for the ED05, from 10.6 to 14.6 mg walnut protein for the ED10, and from 590 to 625 mg of walnut protein for the ED50. CONCLUSIONS: Our data indicate that population EDs for walnut are slightly higher compared with those for peanut and hazelnut allergy. Currently available data indicate that the ED values for hazelnut could be used as a conservative temporary placeholder when implementing risk management strategies for other tree nuts where little or no food challenge data are available

Threshold Dose Distribution in Walnut Allergy

BACKGROUND: In food allergy, eliciting doses (EDs) of foods on a population level can improve risk management and labeling strategies for the food industry and regulatory authorities. Previously, data available for walnut were unsuitable to determine EDs. OBJECTIVE: The objective of this study was to determine EDs for walnut allergic adults and to compare with previously established threshold data for peanut and tree nuts. METHODS: Prospectively, adult subjects with a suspected walnut allergy underwent a low-dose double-blind, placebo-controlled food challenge. Individual no observed and lowest observed adverse effect levels were determined and log-normal, log-logistic, and Weibull models were fit to the data. Estimated ED values were calculated for the ED5, ED10, and ED50, the dose respectively predicted to provoke an allergic reaction in 5%, 10%, and 50% of the walnut allergic population. RESULTS: Fifty-seven subjects were challenged and 33 subjects were confirmed to be walnut allergic. Objective symptoms occurred in 20 of the positive challenges (61%). The cumulative EDs in the distribution models ranged from 3.1 to 4.1 mg for the ED05, from 10.6 to 14.6 mg walnut protein for the ED10, and from 590 to 625 mg of walnut protein for the ED50. CONCLUSIONS: Our data indicate that population EDs for walnut are slightly higher compared with those for peanut and hazelnut allergy. Currently available data indicate that the ED values for hazelnut could be used as a conservative temporary placeholder when implementing risk management strategies for other tree nuts where little or no food challenge data are available

Prevention of work-related airway allergies; summary of the advice from the Health Council of the Netherlands

The Health Council of the Netherlands published a report in which the best procedure and method for recommending health-based occupational exposure limits (OELs) for inhaled allergens were identified by evaluating the scientific state of the art. Many respiratory disorders in the workplace arise from inhalation of substances which can cause allergy. To protect workers against respiratory allergy, various preventive measures are taken, one of them being reduction of exposure by setting legally binding standards. These are based on health-based OELs that specify a level of exposure to an airborne substance, a threshold level, below which it may reasonably be expected that there is no risk of adverse health effects. The Council is of the opinion that an OEL should prevent against allergic sensitization, as sensitization plays a crucial biological role and is a prerequisite for the development of allergy. Furthermore, the Council considers it most likely that the exposure level below which no allergic sensitization develops for most allergens is so low, that OELs are difficult to set with the current knowledge and technical feasibilities. An alternative approach is to accept exposure, which carries a small predefined risk in developing allergic sensitization. In addition, it is worth considering periodic screening of exposed workers on allergic sensitization, because timely intervention can prevent worse. The feasibility of periodic screening and what else is needed to comply with the most important criteria, should however be judged case-by-case