Homeostatic regulation of CD8+ T cells after antigen challenge in the absence of Fas (CD95)

The role of Fas in the homeostatic regulation of CD8⁺ T cells after antigen challenge was analyzed in the murine model of lymphocytic choriomeningitis virus (LCMV) infection. Mice homozygous for the lpr mutation and carrying T cell receptor (TCR) αβ transgenes specific for the LCMV glycoprotein peptide aa 33–41 in the context of H-2D^b were used. Five main results emerged: first, development of lymphadenopathy and of CD4⁻CD8⁻ double-negative B220⁺ T cells in lpr mice was not inhibited by the αβ TCR transgenes; second, tolerance induction and peripheral deletion of CD8⁺ T cells induced by LCMV glycoprotein peptide injection was independent of Fas expression; third, clonal down-regulation of Fas-deficient TCR-transgenic CD8⁺ T cells after acute LCM virus infection was identical to the decline of transgenic T cells expressing Fas; fourth, in vivo activated CD8⁺ effector T cells from TCR transgenic and TCR-lpr/lpr mice were equally susceptible to activation-induced cell death in vitro; and fifth, transgenic effector T cells from lpr/lpr mice were cleared in the declining phase of the immune response in vivo without giving rise to CD4⁻CD8⁻ double-negative T cells. Taken together, these data suggest that the homeostatic regulation of CD8⁺ T cells after antigen challenge in vivo is regulated by mechanisms that do not require Fas.     

Challenges and satisfaction in Cardiothoracic Surgery Residency Programmes: insights from a Europe-wide survey

Open in a separate window OBJECTIVESThe increasing complexity of surgical patients and working time constraints represent challenges for training. In this study, the European Association for Cardio-Thoracic Surgery Residents’ Committee aimed to evaluate satisfaction with current training programmes across Europe. METHODSWe conducted an online survey between October 2018 and April 2019, completed by a total of 219 participants from 24 countries.RESULTSThe average respondent was in the fourth or fifth year of training, mostly on a cardiac surgery pathway. Most trainees follow a 5–6-year programme, with a compulsory final certification exam, but no regular skills evaluation. Only a minority are expected to take the examination by the European Board of Cardiothoracic Surgery. Participants work on average 61.0 ± 13.1 h per week, including 27.1 ± 20.2 on-call. In total, only 19.7% confirmed the implementation of the European Working Time Directive, with 42.0% being unaware that European regulations existed. Having designated time for research was reported by 13.0%, despite 47.0% having a postgraduate degree. On average, respondents rated their satisfaction 7.9 out of 10, although 56.2% of participants were not satisfied with their training opportunities. We found an association between trainee satisfaction and regular skills evaluation, first operator experience and protected research time.CONCLUSIONSOn average, residents are satisfied with their training, despite significant disparities in the quality and structure of cardiothoracic surgery training across Europe. Areas for potential improvement include increasing structured feedback, research time integration and better working hours compliance. The development of European guidelines on training standards may support this.     

A mutation update on the LDS‐associated genes TGFB2/3 and SMAD2/3

The Loeys–Dietz syndrome (LDS) is a connective tissue disorder affecting the cardiovascular, skeletal, and ocular system. Most typically, LDS patients present with aortic aneurysms and arterial tortuosity, hypertelorism, and bifid/broad uvula or cleft palate. Initially, mutations in transforming growth factor‐β (TGF‐β) receptors (TGFBR1 and TGFBR2) were described to cause LDS, hereby leading to impaired TGF‐β signaling. More recently, TGF‐β ligands, TGFB2 and TGFB3, as well as intracellular downstream effectors of the TGF‐β pathway, SMAD2 and SMAD3, were shown to be involved in LDS. This emphasizes the role of disturbed TGF‐β signaling in LDS pathogenesis. Since most literature so far has focused on TGFBR1/2, we provide a comprehensive review on the known and some novel TGFB2/3 and SMAD2/3 mutations. For TGFB2 and SMAD3, the clinical manifestations, both of the patients previously described in the literature and our newly reported patients, are summarized in detail. This clearly indicates that LDS concerns a disorder with a broad phenotypical spectrum that is still emerging as more patients will be identified. All mutations described here are present in the corresponding Leiden Open Variant Database.     

Warming and Salt Intrusion Affect Microcystin Production in Tropical Bloom-Forming Microcystis

The Vietnamese Mekong Delta is predicted to be one of the regions most impacted by climate change, causing increased temperature and salinity in inland waters. We hypothesized that the increase in temperature and salinity may impact the microcystin (MC) production of two Microcystis strains isolated in this region from a freshwater pond (strain MBC) and a brackish water pond (strain MTV). The Microcystis strains were grown at low (27 °C), medium (31 °C), high (35 °C) and extremely high (37 °C) temperature in flat photobioreactors (Algaemist). At each temperature, when cultures reached a stable state, sea salt was added to increase salinity to 4‰, 8‰, 12‰ and 16‰. MC concentrations and cell quota were reduced at high and extremely high temperatures. Salinity, in general, had comparable effects on MC concentrations and quota. At a salinity of 4‰ and 8‰, concentrations of MC per mL of culture and MC cell quota (based on chlorophyll, dry-weight and particle counts) were higher than at 0.5‰, while at the highest salinities (12‰ and 16‰) these were strongly reduced. Strain MBC produced five MC variants of which MC-RR and MC-LR were most abundant, followed by MC-YR and relatively low amounts of demethylated variants dmMC-RR and dmMC-LR. In strain MTV, MC-RR was most abundant, with traces of MC-YR and dmMC-RR only in cultures grown at 16‰ salinity. Overall, higher temperature led to lower MC concentrations and cell quota, low salinity seemed to promote MC production and high salinity reduced MC production. Hence, increased temperature and higher salinity could lead to less toxic Microcystis, but since these conditions might favour Microcystis over other competitors, the overall biomass gain could offset a lower toxicity.     

New and emerging technologies for genetic toxicity testing

The International Life Sciences Institute (ILSI) Health and Environmental Sciences Institute (HESI) Project Committee on the Relevance and Follow‐up of Positive Results in In Vitro Genetic Toxicity (IVGT) Testing established an Emerging Technologies and New Strategies Workgroup to review the current State of the Art in genetic toxicology testing. The aim of the workgroup was to identify promising technologies that will improve genotoxicity testing and assessment of in vivo hazard and risk, and that have the potential to help meet the objectives of the IVGT. As part of this initiative, HESI convened a workshop in Washington, DC in May 2008 to discuss mature, maturing, and emerging technologies in genetic toxicology. This article collates the abstracts of the New and Emerging Technologies Workshop together with some additional technologies subsequently considered by the workgroup. Each abstract (available in the online version of the article) includes a section addressed specifically to the strengths, weaknesses, opportunities, and threats associated with the respective technology. Importantly, an overview of the technologies and an indication of how their use might be aligned with the objectives of IVGT are presented. In particular, consideration was given with regard to follow‐up testing of positive results in the standard IVGT tests (i.e., Salmonella Ames test, chromosome aberration assay, and mouse lymphoma assay) to add weight of evidence and/or provide mechanism of action for improved genetic toxicity risk assessments in humans. Environ. Mol. Mutagen., 2011. © 2010 Wiley‐Liss, Inc.     

Factors increasing the caries risk of second primary molars in 5‐year‐old Dutch children

International Journal of Paediatric Dentistry 2010; 20: 151–157 Background. Caries is still a prevalent condition in 5‐year‐old children. At present, knowledge regarding some aetiological factors, like deciduous molar hypomineralization (DMH), is limited. Aim. To investigate aetiological factors both directly and indirectly associated with caries in second primary molars. Design. Of 974 children invited to participate in the study, 386 children were examined clinically with visual detection of caries. Only carious lesions determined to have reached the dentine were recorded. Information about tooth brushing frequency, education level of the mother, and country of birth of mother and child, was collected by means of a multiple‐choice questionnaire. Parents of 452 children filled in the questionnaire. Complete clinical and questionnaire data were available for 242 children. Statistical analysis of the effect of the independent variables was undertaken using the Pearson’s chi‐squared test. Results. Deciduous molar hypomineralization (P = 0.02) and the country of birth of the mother (P < 0.001) were positively associated with caries prevalence. Conclusions. Deciduous molar hypomineralization and the country of birth of the mother play a role in the prevalence of dental caries. These aetiological factors associated with childhood dental caries need to be investigated further in longitudinal clinical trials.     

Developing a spatial-statistical model and map of historical malaria prevalence in Botswana using a staged variable selection procedure

Background  

Several malaria risk maps have been developed in recent years, many from the prevalence of infection data collated by the MARA (Mapping Malaria Risk in Africa) project, and using various environmental data sets as predictors. Variable selection is a major obstacle due to analytical problems caused by over-fitting, confounding and non-independence in the data. Testing and comparing every combination of explanatory variables in a Bayesian spatial framework remains unfeasible for most researchers. The aim of this study was to develop a malaria risk map using a systematic and practicable variable selection process for spatial analysis and mapping of historical malaria risk in Botswana.     

Expression of prestin-homologous solute carrier (SLC26) in auditory organs of nonmammalian vertebrates and insects

Prestin, the fifth member of the anion transporter family SLC26, is the outer hair cell molecular motor thought to be responsible for active mechanical amplification in the mammalian cochlea. Active amplification is present in a variety of other auditory systems, yet the prevailing view is that prestin is a motor molecule unique to mammalian ears. Here we identify prestin-related SLC26 proteins that are expressed in the auditory organs of nonmammalian vertebrates and insects. Sequence comparisons revealed the presence of SLC26 proteins in fish (Danio, GenBank accession no. AY278118, and Anguilla, GenBank accession no. BAC16761), mosquitoes (Anopheles, GenBank accession nos. EAA07232 and EAA07052), and flies (Drosophila, GenBank accession no. AAF49285). The fly and zebrafish homologues were cloned and, by using in situ hybridization, shown to be expressed in the auditory organs. In mosquitoes, in turn, the expression of prestin homologues was demonstrated for the auditory organ by using highly specific riboprobes against rat prestin. We conclude that prestin-related SLC26 proteins are widespread, possibly ancestral, constituents of auditory organs and are likely to serve salient roles in mammals and across taxa.