Spindles and active vortices in a model of confined filament-motor mixtures

Background

Although biological membranes are organized as lipid bilayers, they contain a substantial fraction of lipids that have a strong tendency to adopt a nonlamellar, most often inverted hexagonal (H_II) phase. The polymorphic phase behavior of such nonbilayer lipids has been studied previously with a variety of methods in the fully hydrated state or at different degrees of dehydration. Here, we present a study of the thermotropic phase behavior of the nonbilayer lipids egg phosphatidylethanolamine (EPE) and monogalactosyldiacylglycerol (MGDG) with a focus on interactions between the lipid molecules in the interfacial and headgroup regions.

Results

Liposomes were investigated in the dry state by Fourier-transform Infrared (FTIR) spectroscopy and Differential Scanning Calorimetry (DSC). Dry EPE showed a gel to liquid-crystalline phase transition below 0°C and a liquid-crystalline to H_II transition at 100°C. MGDG, on the other hand, was in the liquid-crystalline phase down to -30°C and showed a nonbilayer transition at about 85°C. Mixtures (1:1 by mass) with two different phosphatidylcholines (PC) formed bilayers with no evidence for nonbilayer transitions up to 120°C. FTIR spectroscopy revealed complex interactions between the nonbilayer lipids and PC. Strong H-bonding interactions occurred between the sugar headgroup of MGDG and the phosphate, carbonyl and choline groups of PC. Similarly, the ethanolamine moiety of EPE was H-bonded to the carbonyl and choline groups of PC and probably interacted through charge pairing with the phosphate group.

Conclusions

This study provides a comprehensive characterization of dry membranes containing the two most important nonbilayer lipids (PE and MGDG) in living cells. These data will be of particular relevance for the analysis of interactions between membranes and low molecular weight solutes or soluble proteins that are presumably involved in cellular protection during anhydrobiosis.     

Endothelial L-selectin ligand expression in nasal polyps

Background:  L-selectins on leukocytes and their counter-receptors on endothelial cells have been shown to be involved in leukocyte recruitment in chronic rhinosinusitis without nasal polyps (NP).
Objectives:  The purpose of this study was to evaluate the expression level of functionally active endothelial L-selectin ligands in NP obtained from patients with NP of different etiology [simple NP, antro-choanal polyps (ACP) and cystic fibrosis (CF) NP] and inferior turbinate specimens of healthy controls and to compare these levels to the presence of various leukocyte subsets.
Methods:  Nasal polyp specimens and healthy nasal mucosa specimens were obtained from patients undergoing surgery and were immunohistochemically stained with monoclonal antibodies detecting CD34, sialyl Lewis x (sLe^x) of sulfated extended core 1 lactosamines and various leukocyte subsets.
Results:  All NP are characterized by a decrease in the number of CD34+ vessels. The number of eosinophils and the percentage of vessels expressing endothelial sulfated sLe^x epitopes is upregulated in all groups of simple NP. Tissue eosinophilia is increased in those patients with increased disease severity (acetyl salicylic acid intolerance), but the percentage of endothelial sulfated sLe^x epitopes is not. Results on CF NP are similar to those observed for simple NP. Antro-choanal polyps, on the contrary, are characterized by low numbers of tissue eosinophils and relatively few vessels expressing endothelial sulfated sLe^x epitopes.
Conclusions:  Our results suggest that functionally active L-selectin ligands might play a role in guiding leukocyte traffic into NP in patients with simple NP and CF NP but not ACP.     

Recommendations for assessing patient-reported outcomes and health-related quality of life in patients with urticaria: a GA(2) LEN taskforce position paper

The aim of this Global Allergy and Asthma European Network (GA(2)LEN) consensus report is to provide recommendations and suggestions for assessing patient-reported outcomes (PROs) including health-related quality of life in patients with urticaria. We recommend that PROs should be used both in clinical trials and routine practice for the evaluation of urticaria patients. We suggest that PROs should be considered as the primary outcome of future clinical trials. Two validated and disease-specific instruments for assessing PROs are available, the urticaria activity score (for symptoms) and the chronic urticaria questionnaire on quality of life CU-Q(2)oL. This latter tool, CU-Q(2)oL, is available in many languages and should be preferred, where available, over more generic instruments for assessing urticaria-specific effects on quality of life. CU-Q(2)oL is only suited for the investigation of patients with chronic spontaneous urticaria. Similar instruments for other forms of urticaria have yet to be developed and validated. Also, tools for assessing other chronic spontaneous urticaria PROs besides quality of life and symptoms are needed.     

Viruses and bacteria in acute asthma exacerbations--a GA² LEN-DARE systematic review

A major part of the burden of asthma is caused by acute exacerbations. Exacerbations have been strongly and consistently associated with respiratory infections. Respiratory viruses and bacteria are therefore possible treatment targets. To have a reasonable estimate of the burden of disease induced by such infectious agents on asthmatic patients, it is necessary to understand their nature and be able to identify them in clinical samples by employing accurate and sensitive methodologies. This systematic review summarizes current knowledge and developments in infection epidemiology of acute asthma in children and adults, describing the known impact for each individual agent and highlighting knowledge gaps. Among infectious agents, human rhinoviruses are the most prevalent in regard to asthma exacerbations. The newly identified type-C rhinoviruses may prove to be particularly relevant. Respiratory syncytial virus and metapneumovirus are important in infants, while influenza viruses seem to induce severe exacerbations mostly in adults. Other agents are relatively less or not clearly associated. Mycoplasma and Chlamydophila pneumoniae seem to be involved more with asthma persistence rather than with disease exacerbations. Recent data suggest that common bacteria may also be involved, but this should be confirmed. Although current information is considerable, improvements in detection methodologies, as well as the wide variation in respect to location, time and populations, underline the need for additional studies that should also take into account interacting factors.     

Double-strand breaks may initiate the inversion mutation causing the Hunter syndrome

We have previously shown that patients with the Hunter syndrome frequently have suffered from a recombination event between the IDS gene and its putative pseudogene, IDS-2, resulting in an inversion of the intervening DNA. The inversion, which might be the consequence of an intrachromosomal mispairing, is caused by homologous recombination between sequences located in intron 7 of the IDS gene and sequences located distal of exon 3 in IDS-2. In order to gain insight into the mechanisms causing the inversion, we have isolated both inversion junctions in six unrelated patients. DNA sequence analysis of the junctions showed that all recombinations have taken place within a 1 kb region where the sequence identity is >98%. An interesting finding was the identification of regions with alternating IDS gene and IDS-2 sequences present at one inversion junction, suggesting that the recombination event has been initiated by a double-strand break in intron 7 of the IDS gene. The results from this study suggest that homologous recombination in man could be explained by mechanisms similar to those described for Saccharomyces cerevisiae. The results also have practical implications for diagnosis of patients with the Hunter syndrome.      

Nasal epithelial cells express IL-10 at levels that negatively correlate with clinical symptoms in patients with house dust mite allergy

BACKGROUND: Despite constant exposure to micro-organisms and other immunogenic environmental factors, relatively very few immunological responses are initiated in the nasal mucosa. Although several mechanisms could play a role in maintaining this immune suppressive milieu, none of them have been validated. Previous data from our group suggested that locally produced interleukin (IL)-10 could be involved in maintaining local homeostasis. METHODS: To investigate the role of epithelial IL-10 expression in the manifestation of allergic symptoms, we used immunohistochemistry to study the expression of IL-10 in the nasal epithelium of healthy individuals and house dust mite allergic patients. In the allergic patients, we determined potential correlations of epithelial expression with allergic symptoms, both at baseline and after allergen provocation. RESULTS: IL-10 is expressed in the basal and differentiated epithelial cells of both healthy individuals and allergic rhinitis patients. In the allergic individuals, there is a strong negative correlation at baseline between the epithelial expression level of IL-10 and rhinorrhoea and sneezing, but not between that expression level and nasal blockage or peak nasal inspiratory flow (PNIF). This correlation disappears with steroid treatment or after allergen provocation, although the expression at baseline seems to predict PNIF scores after provocation. CONCLUSIONS: Our data not only reveals IL-10 expression by human nasal epithelial cells, but also suggests that nasal epithelial IL-10 regulates allergic symptoms. Targeting the regulation mechanisms affecting IL-10 or targeting the regulation mechanism affected by IL-10 could constitute new options for the treatment of allergic disease.     

Biomarkers for diagnosis and prediction of therapy responses in allergic diseases and asthma

Modern health care requires a proactive and individualized response to diseases, combining precision diagnosis and personalized treatment. Accordingly, the approach to patients with allergic diseases encompasses novel developments in the area of personalized medicine, disease phenotyping and endotyping, and the development and application of reliable biomarkers. A detailed clinical history and physical examination followed by the detection of IgE immunoreactivity against specific allergens still represents the state of the art. However, nowadays, further emphasis focuses on the optimization of diagnostic and therapeutic standards and a large number of studies have been investigating the biomarkers of allergic diseases, including asthma, atopic dermatitis, allergic rhinitis, food allergy, urticaria and anaphylaxis. Various biomarkers have been developed by omics technologies, some of which lead to a better classification of distinct phenotypes or endotypes. The introduction of biologicals to clinical practice increases the need for biomarkers for patient selection, prediction of outcomes and monitoring, to allow for an adequate choice of the duration of these costly and long-lasting therapies. Escalating healthcare costs together with questions about the efficacy of the current management of allergic diseases require further development of a biomarker-driven approach. Here, we review biomarkers in diagnosis and treatment of asthma, atopic dermatitis, allergic rhinitis, viral infections, chronic rhinosinusitis, food allergy, drug hypersensitivity and allergen immunotherapy with a special emphasis on specific IgE, the microbiome and the epithelial barrier. In addition, EAACI guidelines on biologicals are discussed within the perspective of biomarkers.