205 research outputs found

    Expulsion of Symbiotic Algae during Feeding by the Green Hydra – a Mechanism for Regulating Symbiont Density?

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    Background: Algal-cnidarian symbiosis is one of the main factors contributing to the success of cnidarians, and is crucial for the maintenance of coral reefs. While loss of the symbionts (such as in coral bleaching) may cause the death of the cnidarian host, over-proliferation of the algae may also harm the host. Thus, there is a need for the host to regulate the population density of its symbionts. In the green hydra, Chlorohydra viridissima, the density of symbiotic algae may be controlled through host modulation of the algal cell cycle. Alternatively, Chlorohydra may actively expel their endosymbionts, although this phenomenon has only been observed under experimentally contrived stress conditions. Principal Findings: We show, using light and electron microscopy, that Chlorohydra actively expel endosymbiotic algal cells during predatory feeding on Artemia. This expulsion occurs as part of the apocrine mode of secretion from the endodermal digestive cells, but may also occur via an independent exocytotic mechanism. Significance: Our results demonstrate, for the first time, active expulsion of endosymbiotic algae from cnidarians under natural conditions. We suggest this phenomenon may represent a mechanism whereby cnidarians can expel excess symbiotic algae when an alternative form of nutrition is available in the form of prey

    Beta 2 antagonism in acute respiratory failure

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    Post hoc analyses from the B-type natriuretic peptide for Acute Shortness of Breath Evaluation (BASEL)-II-ICU study suggest an association between beta-blocker usage at admission and improved mortality in patients treated in the intensive care unit for acute respiratory failure. Although this evidence is encouraging, there is a need for a phase 2 proof-of-concept randomized controlled trial of beta-blocker therapy in patients admitted with acute respiratory failure

    Consent: an event or a memory in lumbar spinal surgery? A multi-centre, multi-specialty prospective study of documentation and patient recall of consent content.

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    STUDY DESIGN: Prospective, multi-centre, multi-specialty medical notes review and patient interview. PURPOSE: The consenting process is an important communication tool which also carries medico-legal implications. While written consent is a pre-requisite before spinal surgery in the UK, the standard and effectiveness of the process have not been assessed previously. This study assesses standard of written consent for elective lumbar decompressive surgery for degenerative disc disease across different regions and specialties in the UK; level of patient recall of the consent content; and identifies factors which affect patient recall. METHODS: Consent forms of 153 in-patients from 4 centres a, b, c, d were reviewed. Written documentation of intended benefits, alternative treatments and operative risks was assessed. Of them, 108 patients were interviewed within 24 h before or after surgeries to assess recall. RESULTS: The written documentation rates of the operative risks showed significant inter-centre variations in haemorrhage and sphincter disturbance (P = 0.000), but not for others. Analysis of pooled data showed variations in written documentation of risks (P 14 days compared to <2 days before their surgeries had higher recall for paralysis (65.2 vs 43.7%) and recurrence (17.4 vs 2.8%). Patient recall was independent of consenter grade. CONCLUSION: Overall, the standard of written consent for elective lumbar spinal decompressive surgery was sub-optimal, which was partly reflected in the poor patient recall. While consenter seniority did not affect patient recall, younger age and longer consent-to-surgery time improved it

    Comparison of Mental Toughness and Power Test Performances in High-Level Kickboxers by Competitive Success

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    Background Kickboxing is a high-intensity intermittent striking combat sport, which is characterized by complex skills and tactical key actions with short duration. Objectives The present study compared and verified the relationship between mental toughness (MT), countermovement jump (CMJ) and medicine ball throw (MBT) power tests by outcomes of high-level kickboxers during National Championship. Materials and Methods Thirty two high-level male kickboxers (winner = 16 and loser = 16: 21.2 ± 3.1 years, 1.73 ± 0.07 m, and 70.2 ± 9.4 kg) were analyzed using the CMJ, MBT tests and sports mental toughness questionnaire (SMTQ; based in confidence, constancy and control subscales), before the fights of the 2015 national championship (16 bouts). In statistical analysis, Mann-Withney test and a multiple linear regression were used to compare groups and to observe relationships, respectively, P ≀ 0.05. Results The present results showed significant differences between losers vs. winners, respectively, of total MT (7(7;8) vs. 11(10.2;11), confidence (3(3;3) vs. 4(4;4)), constancy (2(2;2) vs. 3(3;3)), control (2(2;3) vs. 4(4;4)) subscales and MBT (4.1(4;4.3) vs. 4.6(4.4;4.8)). The multiple linear regression showed a strong associations between MT results and outcome (r = 0.89), MBT (r = 0.84) and CMJ (r = 0.73). Conclusions The findings suggest that MT will be more predictive of performance in those sports and in the outcome of competition.Ministry of Higher Teaching and Scientific Research, Tunisi

    Augmented Lung Inflammation Protects against Influenza A Pneumonia

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    Influenza pneumonia causes high mortality every year, and pandemic episodes kill millions of people. Influenza-related mortality has been variously ascribed to an ineffective host response that fails to limit viral replication, an excessive host inflammatory response that results in lung injury and impairment of gas exchange, or to bacterial superinfection. We sought to determine whether lung inflammation promoted or impaired host survival in influenza pneumonia.To distinguish among these possible causes of influenza-related death, we induced robust lung inflammation by exposing mice to an aerosolized bacterial lysate prior to challenge with live virus. The treatment induced expression of the inflammatory cytokines IL-6 and TNF in bronchoalveolar lavage fluid 8- and 40-fold greater, respectively, than that caused by lethal influenza infection. Yet, this augmented inflammation was associated with striking resistance to host mortality (0% vs 90% survival, p = 0.0001) and reduced viral titers (p = 0.004). Bacterial superinfection of virus infected lungs was not observed. When mice were repeatedly exposed to the bacterial lysate, as would be clinically desirable during an influenza epidemic, there was no tachyphylaxis of the induced viral resistance. When the bacterial lysate was administered after the viral challenge, there was still some mortality benefit, and when ribavirin was added to the aerosolized bacterial lysate, host survival was synergistically improved (0% vs 93.3% survival, p<0.0001).Together, these data indicate that innate immune resistance to influenza can be effectively stimulated, and suggest that ineffective rather than excessive inflammation is the major cause of mortality in influenza pneumonia

    Identidad Ă©tnica y redes personales entre jĂłvenes de Sarajevo

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    After fieldwork conducted among young people in Sarajevo, we found a relation between the discourses sustained by them and the ethnic categories they use to classify people and to identify themselves. Also we have found that people self-affiliated as "Bosnians" play an important role in the network of multiethnic relationships, in which strong ties, surprisingly, are still very important. Finally we found a relationship between the composition of personal networks and the ethnic discourses that are maintained.DespuĂ©s de un trabajo de campo realizado con un grupo de jĂłvenes en Sarajevo, hemos constatado la existencia de una relaciĂłn entre los discursos que sostienen y las categorĂ­as Ă©tnicas que utilizan tanto para clasificar a los demĂĄs como para auto-identificarse. Asimismo hemos encontrado que los jĂłvenes que se autodenominan "Bosnios" juegan un rol importante en la red de relaciones multiĂ©tnicas, en la que los lazos fuertes, sorprendentemente, son muy importantes. Finalmente hemos hallado una relaciĂłn entre la composiciĂłn de las redes personales y los discursos Ă©tnicos que se sostienen. Vivimos, o creemos vivir, en mĂșltiples "comunidades", imaginadas o no. Al mismo tiempo, el individuo y no el lugar, la familia o el grupo, se sitĂșa en el centro de la vida social y de las comunicaciones (Cf. Wellman, 2001). En este contexto, inducido por el avance del capitalismo flexible (Castells, 1996), pensamos que para entender adecuadamente la identidad o identidades postuladas por los individuos es necesario estudiar las redes personales y su dinĂĄmica. Desde esta perspectiva no podemos hablar de "etnias" o "multietnicidad" sin mĂĄs precisiones, pues son conceptos basados en una concepciĂłn esencialista y estĂĄtica de la identidad individual. El concepto de "sociedad multiĂ©tnica" es utilizado de una manera engañosamente progresista y objetiva, pues lo que en realidad legitima es la existencia de diferencias esenciales entre personas, alejando en lugar de acercar. Sin embargo, somos plenamente conscientes que los discursos esencialistas de la identidad Ă©tnica son omnipresentes, con enormes efectos polĂ­ticos e individuales. Que planteemos que la concepciĂłn esencialista de la identidad sea inapropiada desde un punto de vista acadĂ©mico, no significa que Ă©sta no se utilice polĂ­ticamente y por lo tanto tenga consecuencias formidables en las relaciones sociales. Precisamente el estudio de las redes personales nos permite situarnos en una perspectiva que no utiliza con pretensiones analĂ­ticas conceptos "folk", como son los de "etnia", "pueblo" o "naciĂłn", sino que los sitĂșa en el terreno de los discursos sustentados por los actores (y los estados y medios de comunicaciĂłn) y nos permite contextualizarlos mediante conceptos etic, es decir, impuestos por los investigadores. SĂłlo asĂ­ podemos superar las tautologĂ­as que abundan en los discursos Ă©tnicos
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