A game of russian roulette for a generalist dinoflagellate parasitoid: Host susceptibility is the key to success

© 2016 Alacid, Park, Turon, Petrou and Garcés. Marine microbial interactions involving eukaryotes and their parasites play an important role in shaping the structure of phytoplankton communities. These interactions may alter population densities of the main host, which in turn may have consequences for the other concurrent species. The effect generalist parasitoids exert on a community is strongly dependent on the degree of host specificity. Parvilucifera sinerae is a generalist parasitoid able to infect a wide range of dinoflagellates, including toxic-bloom-forming species. A density-dependent chemical cue has been identified as the trigger for the activation of the infective stage. Together these traits make Parvilucifera-dinoflagellate hosts a good model to investigate the degree of specificity of a generalist parasitoid, and the potential effects that it could have at the community level. Here, we present for the first time, the strategy by which a generalist dinoflagellate parasitoid seeks out its host and determine whether it exhibits host preferences, highlighting key factors in determining infection. Our results demonstrate that in its infective stage, P. sinerae is able to sense potential hosts, but does not actively select among them. Instead, the parasitoids contact the host at random, governed by the encounter probability rate and once encountered, the chance to penetrate inside the host cell and develop the infection strongly depends on the degree of host susceptibility. As such, their strategy for persistence is more of a game of Russian roulette, where the chance of survival is dependent on the susceptibility of the host. Our study identifies P. sinerae as a potential key player in community ecology, where in mixed dinoflagellate communities consisting of hosts that are highly susceptible to infection, parasitoid preferences may mediate coexistence between host species, reducing the dominance of the superior competitor. Alternatively, it may increase competition, leading to species exclusion. If, however, highly susceptible hosts are absent from the community, the parasitoid population could suffer a dilution effect maintaining a lower parasitoid density. Therefore, both host community structure and host susceptibility will determine infectivity in the field

An empirical evaluation of the SF-12, SF-6D, EQ-5D and Michigan Hand Outcome Questionnaire in patients with rheumatoid arthritis of the hand

Background The aim of this study was to assess the psychometric properties, namely acceptability, validity, reliability, interpretability and responsiveness of the EuroQol EQ-5D (EQ-5D visual analogue (VAS) and EQ-5D (utility)), Short Form 12 Dimensions (SF-12), SF-6D and Michigan Hand Outcome Questionnaire (MHQ) in patients with rheumatoid arthritis (RA) of the hand. Methods The empirical investigation was based upon data from a randomised controlled trial of 488 adults with rheumatoid arthritis who had pain and dysfunction of the hands and/or wrists. Participants completed the EQ-5D, SF-12 and MHQ at baseline and at 4 and 12 months follow up. Acceptability was measured using completion rates over time; construct validity using the “known groups” approach, based on pain troublesomeness; convergent validity using spearman’s rho correlation (ρ); reliability using internal consistency (Cronbach’s alpha); interpretability using minimal important differences (MID); and responsiveness using effect sizes and standardised response means (SRM) stratified by level of self-rated improvement in hand and wrist function or level of self-rated benefit and satisfaction from trial treatments. Results At baseline, the study population had a mean age of 62.4 years, a mean MHQ score of 52.1 and included 76% women. The EQ-5D (utility) had the highest completion rates across time points. All instruments discriminated between pre-specified groups based on pain troublesomeness. Convergent validity analysis indicated that the MHQ score correlated strongly with the EQ-5D (ρ = 0.65) and SF-6D (ρ = 0.63) utility scores. The MHQ was most responsive at detecting change in indicators of RA pain severity between baseline and 4 months, whilst minimal important differences varied considerably across PROMs. Conclusions The instruments evaluated in this study displayed varying psychometric properties in the context of RA of the hand. The selection of a preferred instrument in evaluative studies should ultimately depend on the relative importance placed on individual psychometric properties and the importance placed on generation of health utilities for economic evaluation purposes

Can mapping algorithms based on raw scores overestimate QALYs gained by treatment? A comparison of mappings between the Roland–Morris Disability Questionnaire and the EQ-5D-3L based on raw and Differenced Score Data

Introduction Mapping algorithms are increasingly being used to predict health-utility values based on responses or scores from non-preference-based measures, thereby informing economic evaluations. Objectives We explored whether predictions in the EuroQol 5-dimension 3-level instrument (EQ-5D-3L) health-utility gains from mapping algorithms might differ if estimated using differenced versus raw scores, using the Roland–Morris Disability Questionnaire (RMQ), a widely used health status measure for low back pain, as an example. Methods We estimated algorithms mapping within-person changes in RMQ scores to changes in EQ-5D-3L health utilities using data from two clinical trials with repeated observations. We also used logistic regression models to estimate response mapping algorithms from these data to predict within-person changes in responses to each EQ-5D-3L dimension from changes in RMQ scores. Predicted health-utility gains from these mappings were compared with predictions based on raw RMQ data. Results Using differenced scores reduced the predicted health-utility gain from a unit decrease in RMQ score from 0.037 (standard error [SE] 0.001) to 0.020 (SE 0.002). Analysis of response mapping data suggests that the use of differenced data reduces the predicted impact of reducing RMQ scores across EQ-5D-3L dimensions and that patients can experience health-utility gains on the EQ-5D-3L ‘usual activity’ dimension independent from improvements captured by the RMQ. Conclusion Mappings based on raw RMQ data overestimate the EQ-5D-3L health utility gains from interventions that reduce RMQ scores. Where possible, mapping algorithms should reflect within-person changes in health outcome and be estimated from datasets containing repeated observations if they are to be used to estimate incremental health-utility gains

Uptake of Dimethylsulfoniopropionate (DMSP) by Natural Microbial Communities of the Great Barrier Reef (GBR), Australia.

Dimethylsulfoniopropionate (DMSP) is a key organic sulfur compound that is produced by many phytoplankton and macrophytes and is ubiquitous in marine environments. Following its release into the water column, DMSP is primarily metabolised by heterotrophic bacterioplankton, but recent evidence indicates that non-DMSP producing phytoplankton can also assimilate DMSP from the surrounding environment. In this study, we examined the uptake of DMSP by communities of bacteria and phytoplankton within the waters of the Great Barrier Reef (GBR), Australia. We incubated natural GBR seawater with DMSP and quantified the uptake of DMSP by different fractions of the microbial community (>8 µm, 3-8 µm, 8 µm) forming the dominant sink, increasing in particulate DMSP by 44-115% upon DMSP enrichment. Longer-term incubations showed however, that DMSP retention was short lived (<24 h) and microbial responses to DMSP enrichment differed depending on the community carbon and sulfur demand. The response of the microbial communities from inside the reef indicated a preference towards cleaving DMSP into the climatically active aerosol dimethyl sulfide (DMS), whereas communities from the outer reef were sulfur and carbon limited, resulting in more DMSP being utilised by the cells. Our results show that DMSP uptake is shared across members of the microbial community, highlighting larger phytoplankton taxa as potentially relevant DMSP reservoirs and provide new information on sulfur cycling as a function of community metabolism in deeper, oligotrophic GBR waters

Serous cystadenocarcinoma of the pancreas: report of a case and management reflections

<p>Abstract</p> <p>Background</p> <p>Serous adenomas represent 1-2% of pancreatic neoplasms and typically are asymptomatic not requiring any treatment and simple observation is the option of choice. Although, they carry a realistic risk of malignancy despite the general view that they never become malignant. We report a case, which, according to our best knowledge is the 27th case reported in the literature.</p> <p>Methods</p> <p>We reviewed the literature by performing a search in Pub Med and Medline.</p> <p>Results</p> <p>A 86-year old patient known to have a serous cystadenoma of the pancreas treated conservatively through a close clinical and radiological follow up which was unattended for 4 years ending up to our emergency department suffering an acute abdomen. Exploratory laparotomy revealed a perforated prepyloric ulcer which was treated accordingly. Patient died some weeks later due to severe medical co morbidities.</p> <p>Conclusion</p> <p>Serous cystic neoplasms of the pancreas carry a realistic risk of malignancy despite the general view that they never become malignant. In our opinion the treatment strategy of serous cystic neoplasms of the pancreas should be aggressive even in cases of remote metastases since prognosis of the disease is satisfactory</p

Toward a joint catalogue of recent seismicity in western Greece: preliminary results

Οι κατάλογοι με δεδομένα πρώτων αφίξεων των σεισμικών κυμάτων που συντάσσονται από τα τρία μόνιμα σεισμολογικά δίκτυα της Ελλάδας ενοποιήθηκαν και υπέστησαν κοινή επεξεργασία προκειμένου να επαναπροσδιοριστούν οι θέσεις των σεισμικών επικέντρου στη Δυτική Ελλάδα. Τα αποτελέσματα της κοινής επεξεργασίας, που παρουσιάζονται στην παρούσα εργασία, αφορούν στην εξαετία 2000 - 2005 και τη γεωγραφική περιοχή μεταξύ 35-42°Β και 19-22°Α. Μετά τη διαδικασία της ενοποίησης των φάσεων των διάφορων κέντρων, ο αριθμός των σεισμικών γεγονότων στον κατάλογο που προέκυψε αυξήθηκε κατά 3000 περίπου σε σχέση με τους προϋπάρχοντες, επιμέρους καταλόγους. Τα επίκεντρα των σεισμών του ενιαίου καταλόγου επαναπροσδιορίστηκαν με τη χρήση του αλγόριθμου Hypoinverse και διάφορους συνδυασμούς μονοδιάστατων μοντέλων ταχυτήτων που έχουν προταθεί για τον ελλαδικό χώρο και συντελεστές βαρύτητας για τα δεδομένα των φάσεων. Από τους διάφορους συνδυασμούς που δοκιμάστηκαν προέκυψε ότι η βαρύτητα που δίνεται στις φάσεις των S κυμάτων επηρεάζει δραστικότερα τα αποτελέσματα του επανα-προσδιορισμού των επικέντρων. Οι μικρότερες τιμές σφαλμάτων στους χρόνους γένεσης των σεισμών και τη χωροθέτηση των επικέντρων τους κατά την οριζόντια και την κατακόρυφη διεύθυνση προκύπτουν όταν οι φάσεις των S κυμάτων δε χρησιμοποιηθούν. Τα επανα προσδιορισμένα επίκεντρα εμφανίζουν περισσότερο διακριτές συγκεντρώσεις και διαγράφουν με μεγαλύτερη σαφήνεια τις τεκτονικές δομές της περιοχής μελέτης.Routine catalogue phase data of three Greek permanent seismic networks are merged and jointly used to relocate earthquakes in western Greece. Processed data refer to the time period from 2000 to 2005 and to the geographical area between 35- 42°N and 19-22Έ. After the merging procedure, the number of events in the joint catalogue is increased by more than 3000 compared to the individual pre-existing catalogues. Earthquakes are relocated using the Hypoinverse algorithm and several different combinations of ID velocity models and phase weighting schemes. Among these two tested factors, S-phase weights are found to affect the relocation results more drastically. In fact, minimum mean rms, erh and erz values (0.28 sees, 3.6 km and 5.8 km, respectively) are found when S-phases are neglected. Relocated epicenters appear more clustered and illuminate well-known, as well as obscure, seismotectonic structures of the are

Preferences for prenatal diagnosis of sickle-cell disorder: A discrete choice experiment comparing potential service users and health-care providers

BACKGROUND: Non-invasive prenatal diagnosis (NIPD) for sickle-cell disorder (SCD) is moving closer to implementation and studies considering stakeholder preferences are required to underpin strategies for offering NIPD in clinical practice. OBJECTIVE: Determine service user and provider preferences for key attributes of prenatal diagnostic tests for SCD and examine views on NIPD. METHOD: A questionnaire that includes a discrete choice experiment was used to determine the preferences of service users and providers for prenatal tests that varied across three attributes: accuracy, time of test and risk of miscarriage. RESULTS: Adults who were carriers of SCD or affected with the condition (N=67) were recruited from haemoglobinopathy clinics at two maternity units. Health professionals, predominately midwives, who offer antenatal care (N=62) were recruited from one maternity unit. No miscarriage risk was a key driver of decision making for both service users and providers. Service providers placed greater emphasis on accuracy than service users. Current uptake of invasive tests was 63%, whilst predicted uptake of NIPD was 93.8%. Many service users (55.4%) and providers (52.5%) think pressure to have prenatal testing will increase when NIPD for SCD becomes available. CONCLUSIONS: There are clear differences between service users and health professionals' preferences for prenatal tests for sickle-cell disorder. The safety of NIPD is welcomed by parents and uptake is likely to be high. To promote informed choice, pretest counselling should be balanced and not exclusively focused on test safety. Counselling strategies that are sensitive to feelings of pressure to test will be essential