The vicious circle and infection intensity: The case of Trypanosoma microti in field vole populations

Objective: In natural populations, infection and condition may act synergistically to trigger a vicious circle: poor condition predisposes to host infections, which further reduce condition, and so on. If this vicious circle originates from a reduced resistance to infection, it will not only result in greater proneness to becoming infected of those that are in poorer condition, but it may also cause infections of higher intensity. Here, we investigate the temporal relationship between host condition and intensity of infection by a specific pathogen using as a system the dynamics of the protozoan Trypanosoma microti in field vole (Microtus agrestis) populations. Methods and results: With two years of longitudinal data from three monthly-sampled populations, we evaluated if individuals acquiring a high intensity of infection previously had lower haematological indicators of condition (red blood cells [RBCs] and lymphocyte counts) than those that acquired lower infection intensities. Also, the association of these indicators with past and present trypanosome blood levels was investigated. The individuals that developed high levels of parasitaemia were those that previously had low lymphocyte counts. Greater intensity of infection corresponded with lower RBCs only in low to moderate weight females, and no effect of intensity of infection on lymphocyte counts was observed. However, delayed effects of high trypanosome intensity were seen on both RBCs and lymphocytes. Conclusions: The vicious circle may also result in high infection intensity: individuals in poor condition are not only more likely to become infected by one pathogen; they may also be the most important source of infection for that and for other pathogens, and thus key protagonists for parasite dynamics.Fil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Telfer, Sandra. University of Liverpool; Reino UnidoFil: Gebert, Stephanie. University of Liverpool; Reino UnidoFil: Lukomski, Lukasz. University of Liverpool; Reino UnidoFil: Bennett, Malcolm. University of Liverpool; Reino UnidoFil: Begon, Michael. University of Liverpool; Reino Unid

Poor condition and infection: a vicious circle in natural populations

Pathogens may be important for host population dynamics, as they can be a proximate cause of morbidity and mortality. Infection dynamics, in turn, may be dependent on the underlying condition of hosts. There is a clear potential for synergy between infection and condition: poor condition predisposes to host infections, which further reduce condition and so on. To provide empirical data that support this notion, we measured haematological indicators of infection (neutrophils and monocytes) and condition (red blood cells (RBCs) and lymphocytes) in field voles from three populations sampled monthly for 2 years. Mixed-effect models were developed to evaluate two hypotheses, (i) that individuals with low lymphocyte and/or RBC levels are more prone to show elevated haematological indicators of infection when re-sampled four weeks later, and (ii) that a decline in indicators of condition is likely to follow the development of monocytosis or neutrophilia. We found that individuals with low RBC and lymphocyte counts had increased probabilities of developing monocytosis and higher increments in neutrophils, and that high indices of infection (neutrophilia and monocytosis) were generally followed by a declining tendency in the indicators of condition (RBCs and lymphocytes). The vicious circle that these results describe suggests that while pathogens overall may be more important in wildlife dynamics than has previously been appreciated, specific pathogens are likely to play their part as elements of an interactive web rather than independent entities

Erfahrungsbericht eines Blended-learning-Kurses zur Programmiergrundausbildung: Objektorientierte Entwicklung von Web-Anwendungen mit Smalltalkt/Seaside

Im Wintersemester 2011/2012 wurde erstmals das Modul 'Programmierung 1' im Bachelor-Studiengang 'Wirtschaftsinformatik' der NORDAKADEMIE nach einem im Rahmen des Projekts 'Westpol' entwickelten Konzepts unterrichtet. Die Wurzeln dieses Konzepts und die Rahmenbedingungen der Kursdurchführung werden in diesem Arbeitspapier erläutert. Ebenfalls wird über die dabei gemachten Erfahrungen berichtet, die auf wöchentlich festgehaltenen Feedbacks der Studierenden basieren. Dazu wurde von den Autoren die Vielzahl der Feedbacks gesichtet und versucht, nach verschiedenen Kriterien zu gruppieren, um damit eine ausreichende Grundlage für eine spätere Überarbeitung des Kurses zu erhalten

Serviços de terapia antineoplásica: segurança dos trabalhadores e risco químico

Updated study with the purpose of making a survey of the necessary actions for a safe practice in Antineoplastic Therapy Services (ATS), in the perspective of protecting worker’s health in relation to chemical occupational risk present in the work environment, while maneuvering Antineoplastic Chemotherapy (AQ). Safety practices were categorized in relative to professionals; handling of AQ; individual and collective; use of materials; transport of AQ; application of AQ; discard of toxic waste; environmental dumping and personal contamination and patient handling, based on benchmarks of National Institute of Cancer (NICA), and of BONASSA and SANTANA, and of Collegiate Directory Resolution (CDR) 220. The theoretical framework on the subject provides subsidies to safety actions and practices, pointing to ideal and legal work conditions and instrumenting the ATS workers for the conscious and risk-free labor exerciseEste trabajo propone un estudio de actualización con la finalidad de hacer una encuesta sobre acciones necesarias para una práctica segura en los Servicios de Terapia Antineoplásica (STA), ambicionando una perspectiva de protección de la salud del trabajador en relación al riesgo ocupacional químico, que se encuentra en el ambiente de trabajo, cuando este manosea Quimioterapia Antineoplásica (QA). Las prácticas de seguridad fueron distribuidas en categorías según quienes las utilizan; manipulación de QA; individual y colectiva; uso de materiales; transporte de QA; administración de QA; desechar residuos tóxicos; derramamiento ambiental, contaminación personal, manoseo de pacientes, según los referenciales del Instituto Nacional de Cáncer (INCA), BONASSA y SANTANA y de Resolución de la Directoria Colegiada (RDC) 220. La teoria sobre el tema permite obtener subsidios para acciones y prácticas seguras; apuntar condiciones ideales/legales de trabajo e instrumentalizar trabajadores de los STA para un ejercicio laboral consciente y libre de riesgos. Estudo de atualização com o propósito de fazer um levantamento das ações necessárias para uma prática segura nos Serviços de Terapia Antineoplásica (STA), na perspectiva de proteção da saúde do trabalhador em relação ao risco ocupacional químico presente no ambiente de trabalho, ao manusear Quimioterapia Antineoplásica (QA). As práticas de segurança foram categorizadas em relativa aos profissionais; manipulação da QA; individual e coletiva; uso de materiais; transporte da QA; administração de QA; descarte de resíduos tóxicos; derramamento ambiental e contaminação pessoal e manuseio de pacientes, com base nos referenciais do Instituto Nacional do Câncer (INCA), de BONASSA e SANTANA e da Resolução da Diretoria Colegiada (RDC) 220. A sustentação teórica acerca da temática fornece subsídios às ações e práticas seguras ao apontar condições ideais e legais de trabalho e instrumentalizar os trabalhadores dos STA para o exercício laboral consciente e livre de riscos

SARS-CoV-2 T Cell Response in Severe and Fatal COVID-19 in Primary Antibody Deficiency Patients Without Specific Humoral Immunity

Morbidity and mortality of COVID-19 is increased in patients with inborn errors of immunity (IEI). Age and comorbidities and also impaired type I interferon immunity were identified as relevant risk factors. In patients with primary antibody deficiency (PAD) and lack of specific humoral immune response to SARS-CoV-2, clinical disease outcome is very heterogeneous. Despite extensive clinical reports, underlying immunological mechanisms are poorly characterized and levels of T cellular and innate immunity in severe cases remain to be determined. In the present study, we report clinical and immunological findings of 5 PAD patients with severe and fatal COVID-19 and undetectable specific humoral immune response to SARS-CoV-2. Reactive T cells to SARS-CoV-2 spike (S) and nucleocapsid (NCAP) peptide pools were analyzed comparatively by flow cytometry in PAD patients, convalescents and naive healthy individuals. All examined PAD patients developed a robust T cell response. The presence of polyfunctional cytokine producing activated CD4(+) T cells indicates a memory-like phenotype. An analysis of innate immune response revealed elevated CD169 (SIGLEC1) expression on monocytes, a surrogate marker for type I interferon response, and presence of type I interferon autoantibodies was excluded. SARS-CoV-2 RNA was detectable in peripheral blood in three severe COVID-19 patients with PAD. Viral clearance in blood was observed after treatment with COVID-19 convalescent plasma/monoclonal antibody administration. However, prolonged mucosal viral shedding was observed in all patients (median 67 days) with maximum duration of 127 days. PAD patients without specific humoral SARS-CoV-2 immunity may suffer from severe or fatal COVID-19 despite robust T cell and normal innate immune response. Intensified monitoring for long persistence of SARS-CoV-2 viral shedding and (prophylactic) convalescent plasma/specific IgG as beneficial treatment option in severe cases with RNAemia should be considered in seronegative PAD patients

Inflammaging is driven by upregulation of innate immune receptors and systemic interferon signaling and is ameliorated by dietary restriction

Aging is characterized by a chronic low-grade inflammation known as inflammaging in multiple tissues, representing a risk factor for age-related diseases. Dietary restriction (DR) is the best-known non-invasive method to ameliorate aging in many organisms. However, the molecular mechanism and the signaling pathways that drive inflammaging across different tissues and how they are modulated by DR are not yet understood. Here we identify a multi-tissue gene network regulating inflammaging. This network is characterized by chromatin opening and upregulation in the transcription of innate immune system receptors and by activation of interferon signaling through interferon regulatory factors, inflammatory cytokines, and Stat1-mediated transcription. DR ameliorates aging-induced alterations of chromatin accessibility and RNA transcription of the inflammaging gene network while failing to rescue those alterations on the rest of the genome. Our results present a comprehensive understanding of the molecular network regulating inflammation in aging and DR and provide anti-inflammaging therapeutic targets

Many-particle effects in optical transitions from zero-mode Landau levels in HgTe quantum wells

International audienceWe report on the far-infrared magnetospectroscopy of HgTe quantum wells with inverted band ordering at different electron concentrations. We particularly focus on optical transitions from zero-mode Landau levels, which split from the edges of electron-like and hole-like bands. We observe a pronounced dependence of the transition energies on the electron concentration varied by persistent photoconductivity effect. This is striking evidence that in addition to the already well-documented crystalline and interface asymmetries, electron-electron interactions also have a significant impact on the usual behavior of the optical transitions from zero mode Landau levels

Quantum Hall states in inverted HgTe quantum wells probed by transconductance fluctuations

We investigated quantum Hall states in an inverted HgTe quantum well (QW) close to the critical thickness using transconductance fluctuation (TF) measurements. In the conduction band, several integer quantum Hall states were observed, corresponding to filling factors ν=1,2,3,4. For magnetic fields above 2 T, quantum Hall states ν=0 were observed in the normal gap. These observations agreed well with the previous studies of quantum Hall states on GaAs QWs and graphene. Interestingly, TFs corresponding to anomalous positive filling factor ν were clearly observed in the valence band. We attribute the emergence of those TFs to the localization and charging of the heavy holes located in the side maxima of the valence band

Terahertz cyclotron emission of two-dimensional Dirac fermions

Abstract Since the emergence of graphene, we have seen several proposals for the realization of Landau lasers tunable over the terahertz frequency range. The hope was that the non-equidistance of the Landau levels from Dirac fermions would suppress the harmful non-radiative Auger recombination. Unfortunately, even with this non-equidistance an unfavorable non-radiative process persists in Landau-quantized graphene, and so far no cyclotron emission from Dirac fermions has been reported. One way to eliminate this last non-radiative process is to sufficiently modify the dispersion of the Landau levels by opening a small gap in the linear band structure. A proven example of such gapped graphene-like materials are HgTe quantum wells close to the topological phase transition. In this work, we experimentally demonstrate Landau emission from Dirac fermions in such HgTe quantum wells, where the emission is tunable by both the magnetic field and the carrier concentration. Consequently, these results represent an advance in the realization of terahertz Landau lasers tunable by magnetic field and gate-voltage